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diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..6833f05 --- /dev/null +++ b/.gitattributes @@ -0,0 +1,3 @@ +* text=auto +*.txt text +*.md text diff --git a/874-h.zip b/874-h.zip Binary files differnew file mode 100644 index 0000000..a805c0e --- /dev/null +++ b/874-h.zip diff --git a/874-h/874-h.htm b/874-h/874-h.htm new file mode 100644 index 0000000..45c303d --- /dev/null +++ b/874-h/874-h.htm @@ -0,0 +1,14411 @@ +<?xml version="1.0" encoding="us-ascii"?> + +<!DOCTYPE html + PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd" > + +<html xmlns="http://www.w3.org/1999/xhtml" lang="en"> + <head> + <title> + A History of Aeronautics, by E. Charles Vivian + </title> + <style type="text/css" xml:space="preserve"> + + body { margin:5%; background:#faebd0; text-align:justify} + P { text-indent: 1em; margin-top: .25em; margin-bottom: .25em; } + H1,H2,H3,H4,H5,H6 { text-align: center; margin-left: 15%; margin-right: 15%; } + hr { width: 50%; text-align: center;} + .foot { margin-left: 20%; margin-right: 20%; text-align: justify; text-indent: -3em; font-size: 90%; } + blockquote {font-size: 97%; font-style: italic; margin-left: 10%; margin-right: 10%;} + .mynote {background-color: #DDE; color: #000; padding: .5em; margin-left: 10%; margin-right: 10%; font-family: sans-serif; font-size: 95%;} + .toc { margin-left: 10%; margin-bottom: .75em;} + .toc2 { margin-left: 20%;} + div.fig { display:block; margin:0 auto; text-align:center; } + div.middle { margin-left: 20%; margin-right: 20%; text-align: justify; } + .figleft {float: left; margin-left: 0%; margin-right: 1%;} + .figright {float: right; margin-right: 0%; margin-left: 1%;} + .pagenum {display:inline; font-size: 70%; font-style:normal; + margin: 0; padding: 0; position: absolute; right: 1%; + text-align: right;} + pre { font-style: italic; font-size: 90%; margin-left: 10%;} + +</style> + </head> + <body> +<pre xml:space="preserve"> + +The Project Gutenberg EBook of A History of Aeronautics, by E. Charles Vivian + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: A History of Aeronautics + +Author: E. Charles Vivian + +Release Date: July 26, 2008 [EBook #874] +Last Updated: February 7, 2013 + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK A HISTORY OF AERONAUTICS *** + + + + +Produced by Dianne Bean, and David Widger + + + + + +</pre> + <p> + <br /><br /> + </p> + <h1> + A HISTORY OF AERONAUTICS + </h1> + <p> + <br /> + </p> + <h2> + by E. Charles Vivian + </h2> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> <a name="link2H_FORE" id="link2H_FORE"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + FOREWORD + </h2> + <p> + Although successful heavier-than-air flight is less than two decades old, + and successful dirigible propulsion antedates it by a very short period, + the mass of experiment and accomplishment renders any one-volume history + of the subject a matter of selection. In addition to the restrictions + imposed by space limits, the material for compilation is fragmentary, and, + in many cases, scattered through periodical and other publications. + Hitherto, there has been no attempt at furnishing a detailed account of + how the aeroplane and the dirigible of to-day came to being, but each + author who has treated the subject has devoted his attention to some + special phase or section. The principal exception to this rule—Hildebrandt—wrote + in 1906, and a good many of his statements are inaccurate, especially with + regard to heavier-than-air experiment. + </p> + <p> + Such statements as are made in this work are, where possible, given with + acknowledgment to the authorities on which they rest. Further + acknowledgment is due to Lieut.-Col. Lockwood Marsh, not only for the + section on aeroplane development which he has contributed to the work, but + also for his kindly assistance and advice in connection with the section + on aerostation. The author's thanks are also due to the Royal Aeronautical + Society for free access to its valuable library of aeronautical + literature, and to Mr A. Vincent Clarke for permission to make use of his + notes on the development of the aero engine. + </p> + <p> + In this work is no claim to originality—it has been a matter mainly + of compilation, and some stories, notably those of the Wright Brothers and + of Santos Dumont, are better told in the words of the men themselves than + any third party could tell them. The author claims, however, that this is + the first attempt at recording the facts of development and stating, as + fully as is possible in the compass of a single volume, how flight and + aerostation have evolved. The time for a critical history of the subject + is not yet. + </p> + <p> + In the matter of illustrations, it has been found very difficult to secure + suitable material. Even the official series of photographs of aeroplanes + in the war period is curiously incomplete' and the methods of censorship + during that period prevented any complete series being privately + collected. Omissions in this respect will probably be remedied in future + editions of the work, as fresh material is constantly being located. + </p> + <p> + E.C.V. October, 1920. + </p> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> + </p> + <blockquote> + <p class="toc"> + <big><b>CONTENTS</b></big> + </p> + <p> + <br /> + </p> + <p class="toc"> + <a href="#link2H_FORE"> FOREWORD </a> + </p> + <p> + <br /> + </p> + <p class="toc"> + <a href="#link2H_PART"> <b>PART I. THE EVOLUTION OF THE AEROPLANE</b> + </a> + </p> + <p class="toc"> + <a href="#link2H_4_0003"> I. THE PERIOD OF LEGEND </a> + </p> + <p class="toc"> + <a href="#link2H_4_0004"> II. EARLY EXPERIMENTS </a> + </p> + <p class="toc"> + <a href="#link2H_4_0005"> III. SIR GEORGE CAYLEY—THOMAS WALKER + </a> + </p> + <p class="toc"> + <a href="#link2H_4_0006"> IV. THE MIDDLE NINETEENTH CENTURY </a> + </p> + <p class="toc"> + <a href="#link2H_4_0007"> V. WENHAM, LE BRIS, AND SOME OTHERS </a> + </p> + <p class="toc"> + <a href="#link2H_4_0008"> VI. THE AGE OF THE GIANTS </a> + </p> + <p class="toc"> + <a href="#link2H_4_0009"> VII. LILIENTHAL AND PILCHER </a> + </p> + <p class="toc"> + <a href="#link2H_4_0010"> VIII. AMERICAN GLIDING EXPERIMENTS </a> + </p> + <p class="toc"> + <a href="#link2H_4_0011"> IX. NOT PROVEN </a> + </p> + <p class="toc"> + <a href="#link2H_4_0012"> X. SAMUEL PIERPOINT LANGLEY </a> + </p> + <p class="toc"> + <a href="#link2H_4_0013"> XI. THE WRIGHT BROTHERS </a> + </p> + <p class="toc"> + <a href="#link2H_4_0014"> XII. THE FIRST YEARS OF CONQUEST </a> + </p> + <p class="toc"> + <a href="#link2H_4_0015"> XIII. FIRST FLIERS IN ENGLAND </a> + </p> + <p class="toc"> + <a href="#link2H_4_0016"> XIV. RHEIMS, AND AFTER </a> + </p> + <p class="toc"> + <a href="#link2H_4_0017"> XV. THE CHANNEL CROSSING </a> + </p> + <p class="toc"> + <a href="#link2H_4_0018"> XVI. LONDON TO MANCHESTER </a> + </p> + <p class="toc"> + <a href="#link2H_4_0019"> XVII. A SUMMARY, TO 1911 </a> + </p> + <p class="toc"> + <a href="#link2H_4_0020"> XVIII. A SUMMARY, TO 1914 </a> + </p> + <p class="toc"> + <a href="#link2H_4_0021"> XIX. THE WAR PERIOD—I </a> + </p> + <p class="toc"> + <a href="#link2H_4_0022"> XX. THE WAR PERIOD—II </a> + </p> + <p class="toc"> + <a href="#link2H_4_0023"> XXI. RECONSTRUCTION </a> + </p> + <p class="toc"> + <a href="#link2H_4_0024"> XXII. 1919-20 </a> + </p> + <p> + <br /> + </p> + <p class="toc"> + <a href="#link2H_PART2"> <b>PART II. 1903-1920: PROGRESS IN DESIGN</b> + </a> + </p> + <p class="toc"> + <a href="#link2H_4_0026"> I. THE BEGINNINGS </a> + </p> + <p class="toc"> + <a href="#link2H_4_0027"> II. MULTIPLICITY OF IDEAS </a> + </p> + <p class="toc"> + <a href="#link2H_4_0028"> III. PROGRESS ON STANDARDISED LINES </a> + </p> + <p class="toc"> + <a href="#link2H_4_0029"> IV. THE WAR PERIOD </a> + </p> + <p> + <br /> + </p> + <p class="toc"> + <a href="#link2H_PART3"> <b>PART III. AEROSTATICS</b> </a> + </p> + <p class="toc"> + <a href="#link2H_4_0031"> I. BEGINNINGS </a> + </p> + <p class="toc"> + <a href="#link2H_4_0032"> II. THE FIRST DIRIGIBLES </a> + </p> + <p class="toc"> + <a href="#link2H_4_0033"> III. SANTOS-DUMONT </a> + </p> + <p class="toc"> + <a href="#link2H_4_0034"> IV. THE MILITARY DIRIGIBLE </a> + </p> + <p class="toc"> + <a href="#link2H_4_0035"> V. BRITISH AIRSHIP DESIGN </a> + </p> + <p class="toc"> + <a href="#link2H_4_0036"> VI. THE AIRSHIP COMMERCIALLY </a> + </p> + <p class="toc"> + <a href="#link2H_4_0037"> VII. KITE BALLOONS </a> + </p> + <p> + <br /> + </p> + <p class="toc"> + <a href="#link2H_PART4"> <b>PART IV. ENGINE DEVELOPMENT</b> </a> + </p> + <p class="toc"> + <a href="#link2H_4_0039"> I. THE VERTICAL TYPE </a> + </p> + <p class="toc"> + <a href="#link2H_4_0040"> II. THE VEE TYPE </a> + </p> + <p class="toc"> + <a href="#link2H_4_0041"> III. THE RADIAL TYPE </a> + </p> + <p class="toc"> + <a href="#link2H_4_0042"> IV. THE ROTARY TYPE </a> + </p> + <p class="toc"> + <a href="#link2H_4_0043"> V. THE HORIZONTALLY-OPPOSED ENGINE </a> + </p> + <p class="toc"> + <a href="#link2H_4_0044"> VI. THE TWO-STROKE CYCLE ENGINE </a> + </p> + <p class="toc"> + <a href="#link2H_4_0045"> VII. ENGINES OF THE WAR PERIOD </a> + </p> + <p> + <br /> + </p> + <p class="toc"> + <a href="#link2H_APPEa"> APPENDIX A </a> + </p> + <p class="toc"> + <a href="#link2H_APPEb"> APPENDIX B </a> + </p> + <p class="toc"> + <a href="#link2H_APPEc"> APPENDIX C </a> + </p> + </blockquote> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> <a name="link2H_PART" id="link2H_PART"> + <!-- H2 anchor --> </a> + </p> + <h2> + PART I. THE EVOLUTION OF THE AEROPLANE + </h2> + <p> + <a name="link2H_4_0003" id="link2H_4_0003"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + I. THE PERIOD OF LEGEND + </h2> + <p> + The blending of fact and fancy which men call legend reached its fullest + and richest expression in the golden age of Greece, and thus it is to + Greek mythology that one must turn for the best form of any legend which + foreshadows history. Yet the prevalence of legends regarding flight, + existing in the records of practically every race, shows that this form of + transit was a dream of many peoples—man always wanted to fly, and + imagined means of flight. + </p> + <p> + In this age of steel, a very great part of the inventive genius of man has + gone into devices intended to facilitate transport, both of men and goods, + and the growth of civilisation is in reality the facilitation of transit, + improvement of the means of communication. He was a genius who first + hoisted a sail on a boat and saved the labour of rowing; equally, he who + first harnessed ox or dog or horse to a wheeled vehicle was a genius—and + these looked up, as men have looked up from the earliest days of all, + seeing that the birds had solved the problem of transit far more + completely than themselves. So it must have appeared, and there is no age + in history in which some dreamers have not dreamed of the conquest of the + air; if the caveman had left records, these would without doubt have + showed that he, too, dreamed this dream. His main aim, probably, was + self-preservation; when the dinosaur looked round the corner, the + prehistoric bird got out of the way in his usual manner, and prehistoric + man, such of him as succeeded in getting out of the way after his fashion—naturally + envied the bird, and concluded that as lord of creation in a doubtful sort + of way he ought to have equal facilities. He may have tried, like Simon + the Magician, and other early experimenters, to improvise those + facilities; assuming that he did, there is the groundwork of much of the + older legend with regard to men who flew, since, when history began, + legends would be fashioned out of attempts and even the desire to fly, + these being compounded of some small ingredient of truth and much + exaggeration and addition. + </p> + <p> + In a study of the first beginnings of the art, it is worth while to + mention even the earliest of the legends and traditions, for they show the + trend of men's minds and the constancy of this dream that has become + reality in the twentieth century. In one of the oldest records of the + world, the Indian classic Mahabarata, it is stated that 'Krishna's enemies + sought the aid of the demons, who built an aerial chariot with sides of + iron and clad with wings. The chariot was driven through the sky till it + stood over Dwarakha, where Krishna's followers dwelt, and from there it + hurled down upon the city missiles that destroyed everything on which they + fell.' Here is pure fable, not legend, but still a curious forecast of + twentieth century bombs from a rigid dirigible. It is to be noted in this + case, as in many, that the power to fly was an attribute of evil, not of + good—it was the demons who built the chariot, even as at + Friedrichshavn. Mediaeval legend in nearly every case, attributes flight + to the aid of evil powers, and incites well-disposed people to stick to + the solid earth—though, curiously enough, the pioneers of medieval + times were very largely of priestly type, as witness the monk of + Malmesbury. + </p> + <p> + The legends of the dawn of history, however, distribute the power of + flight with less of prejudice. Egyptian sculpture gives the figure of + winged men; the British Museum has made the winged Assyrian bulls familiar + to many, and both the cuneiform records of Assyria and the hieroglyphs of + Egypt record flights that in reality were never made. The desire fathered + the story then, and until Clement Ader either hopped with his Avion, as is + persisted by his critics, or flew, as is claimed by his friends. + </p> + <p> + While the origin of many legends is questionable, that of others is easy + enough to trace, though not to prove. Among the credulous the significance + of the name of a people of Asia Minor, the Capnobates, 'those who travel + by smoke,' gave rise to the assertion that Montgolfier was not first in + the field—or rather in the air—since surely this people must + have been responsible for the first hot-air balloons. Far less + questionable is the legend of Icarus, for here it is possible to trace a + foundation of fact in the story. Such a tribe as Daedalus governed could + have had hardly any knowledge of the rudiments of science, and even their + ruler, seeing how easy it is for birds to sustain themselves in the air, + might be excused for believing that he, if he fashioned wings for himself, + could use them. In that belief, let it be assumed, Daedalus made his + wings; the boy, Icarus, learning that his father had determined on an + attempt at flight secured the wings and fastened them to his own + shoulders. A cliff seemed the likeliest place for a 'take-off,' and Icarus + leaped from the cliff edge only to find that the possession of wings was + not enough to assure flight to a human being. The sea that to this day + bears his name witnesses that he made the attempt and perished by it. + </p> + <p> + In this is assumed the bald story, from which might grow the legend of a + wise king who ruled a peaceful people—'judged, sitting in the sun,' + as Browning has it, and fashioned for himself wings with which he flew + over the sea and where he would, until the prince, Icarus, desired to + emulate him. Icarus, fastening the wings to his shoulders with wax, was so + imprudent as to fly too near the sun, when the wax melted and he fell, to + lie mourned of water-nymphs on the shores of waters thenceforth Icarian. + Between what we have assumed to be the base of fact, and the legend which + has been invested with such poetic grace in Greek story, there is no more + than a century or so of re-telling might give to any event among a people + so simple and yet so given to imagery. + </p> + <p> + We may set aside as pure fable the stories of the winged horse of Perseus, + and the flights of Hermes as messenger of the gods. With them may be + placed the story of Empedocles, who failed to take Etna seriously enough, + and found himself caught by an eruption while within the crater, so that, + flying to safety in some hurry, he left behind but one sandal to attest + that he had sought refuge in space—in all probability, if he escaped + at all, he flew, but not in the sense that the aeronaut understands it. + But, bearing in mind the many men who tried to fly in historic times, the + legend of Icarus and Daedalus, in spite of the impossible form in which it + is presented, may rank with the story of the Saracen of Constantinople, or + with that of Simon the Magician. A simple folk would naturally idealise + the man and magnify his exploit, as they magnified the deeds of some + strong man to make the legends of Hercules, and there, full-grown from a + mere legend, is the first record of a pioneer of flying. Such a theory is + not nearly so fantastic as that which makes the Capnobates, on the + strength of their name, the inventors of hot-air balloons. However it may + be, both in story and in picture, Icarus and his less conspicuous father + have inspired the Caucasian mind, and the world is the richer for them. + </p> + <p> + Of the unsupported myths—unsupported, that is, by even a shadow of + probability—there is no end. Although Latin legend approaches nearer + to fact than the Greek in some cases, in others it shows a disregard for + possibilities which renders it of far less account. Thus Diodorus of + Sicily relates that one Abaris travelled round the world on an arrow of + gold, and Cassiodorus and Glycas and their like told of mechanical birds + that flew and sang and even laid eggs. More credible is the story of Aulus + Gellius, who in his Attic Nights tells how Archytas, four centuries prior + to the opening of the Christian era, made a wooden pigeon that actually + flew by means of a mechanism of balancing weights and the breath of a + mysterious spirit hidden within it. There may yet arise one credulous + enough to state that the mysterious spirit was precursor of the internal + combustion engine, but, however that may be, the pigeon of Archytas almost + certainly existed, and perhaps it actually glided or flew for short + distances—or else Aulus Gellius was an utter liar, like Cassiodorus + and his fellows. In far later times a certain John Muller, better known as + Regiomontanus, is stated to have made an artificial eagle which + accompanied Charles V. on his entry to and exit from Nuremberg, flying + above the royal procession. But, since Muller died in 1436 and Charles was + born in 1500, Muller may be ruled out from among the pioneers of + mechanical flight, and it may be concluded that the historian of this + event got slightly mixed in his dates. + </p> + <p> + Thus far, we have but indicated how one may draw from the richest stores + from which the Aryan mind draws inspiration, the Greek and Latin + mythologies and poetic adaptations of history. The existing legends of + flight, however, are not thus to be localised, for with two possible + exceptions they belong to all the world and to every civilisation, however + primitive. The two exceptions are the Aztec and the Chinese; regarding the + first of these, the Spanish conquistadores destroyed such civilisation as + existed in Tenochtitlan so thoroughly that, if legend of flight was among + the Aztec records, it went with the rest; as to the Chinese, it is more + than passing strange that they, who claim to have known and done + everything while the first of history was shaping, even to antedating the + discovery of gunpowder that was not made by Roger Bacon, have not yet set + up a claim to successful handling of a monoplane some four thousand years + ago, or at least to the patrol of the Gulf of Korea and the Mongolian + frontier by a forerunner of the 'blimp.' + </p> + <p> + The Inca civilisation of Peru yields up a myth akin to that of Icarus, + which tells how the chieftain Ayar Utso grew wings and visited the sun—it + was from the sun, too, that the founders of the Peruvian Inca dynasty, + Manco Capac and his wife Mama Huella Capac, flew to earth near Lake + Titicaca, to make the only successful experiment in pure tyranny that the + world has ever witnessed. Teutonic legend gives forth Wieland the Smith, + who made himself a dress with wings and, clad in it, rose and descended + against the wind and in spite of it. Indian mythology, in addition to the + story of the demons and their rigid dirigible, already quoted, gives the + story of Hanouam, who fitted himself with wings by means of which he + sailed in the air and, according to his desire, landed in the sacred + Lauka. Bladud, the ninth king of Britain, is said to have crowned his + feats of wizardry by making himself wings and attempting to fly—but + the effort cost him a broken neck. Bladud may have been as mythic as + Uther, and again he may have been a very early pioneer. The Finnish epic, + 'Kalevala,' tells how Ilmarinen the Smith 'forged an eagle of fire,' with + 'boat's walls between the wings,' after which he 'sat down on the bird's + back and bones,' and flew. + </p> + <p> + Pure myths, these, telling how the desire to fly was characteristic of + every age and every people, and how, from time to time, there arose an + experimenter bolder than his fellows, who made some attempt to translate + desire into achievement. And the spirit that animated these pioneers, in a + time when things new were accounted things accursed, for the most part, + has found expression in this present century in the utter daring and + disregard of both danger and pain that stamps the flying man, a type of + humanity differing in spirit from his earthbound fellows as fully as the + soldier differs from the priest. + </p> + <p> + Throughout mediaeval times, records attest that here and there some man + believed in and attempted flight, and at the same time it is clear that + such were regarded as in league with the powers of evil. There is the + half-legend, half-history of Simon the Magician, who, in the third year of + the reign of Nero announced that he would raise himself in the air, in + order to assert his superiority over St Paul. The legend states that by + the aid of certain demons whom he had prevailed on to assist him, he + actually lifted himself in the air—but St Paul prayed him down + again. He slipped through the claws of the demons and fell headlong on the + Forum at Rome, breaking his neck. The 'demons' may have been some + primitive form of hot-air balloon, or a glider with which the magician + attempted to rise into the wind; more probably, however, Simon threatened + to ascend and made the attempt with apparatus as unsuitable as Bladud's + wings, paying the inevitable penalty. Another version of the story gives + St Peter instead of St Paul as the one whose prayers foiled Simon—apart + from the identity of the apostle, the two accounts are similar, and both + define the attitude of the age toward investigation and experiment in + things untried. + </p> + <p> + Another and later circumstantial story, with similar evidence of some fact + behind it, is that of the Saracen of Constantinople, who, in the reign of + the Emperor Comnenus—some little time before Norman William made + Saxon Harold swear away his crown on the bones of the saints at Rouen—attempted + to fly round the hippodrome at Constantinople, having Comnenus among the + great throng who gathered to witness the feat. The Saracen chose for his + starting-point a tower in the midst of the hippodrome, and on the top of + the tower he stood, clad in a long white robe which was stiffened with + rods so as to spread and catch the breeze, waiting for a favourable wind + to strike on him. The wind was so long in coming that the spectators grew + impatient. 'Fly, O Saracen!' they called to him. 'Do not keep us waiting + so long while you try the wind!' Comnenus, who had present with him the + Sultan of the Turks, gave it as his opinion that the experiment was both + dangerous and vain, and, possibly in an attempt to controvert such + statement, the Saracen leaned into the wind and 'rose like a bird 'at the + outset. But the record of Cousin, who tells the story in his Histoire de + Constantinople, states that 'the weight of his body having more power to + drag him down than his artificial wings had to sustain him, he broke his + bones, and his evil plight was such that he did not long survive.' + </p> + <p> + Obviously, the Saracen was anticipating Lilienthal and his gliders by some + centuries; like Simon, a genuine experimenter—both legends bear the + impress of fact supporting them. Contemporary with him, and belonging to + the history rather than the legends of flight, was Oliver, the monk of + Malmesbury, who in the year 1065 made himself wings after the pattern of + those supposed to have been used by Daedalus, attaching them to his hands + and feet and attempting to fly with them. Twysden, in his Historiae + Anglicanae Scriptores X, sets forth the story of Oliver, who chose a high + tower as his starting-point, and launched himself in the air. As a matter + of course, he fell, permanently injuring himself, and died some time + later. + </p> + <p> + After these, a gap of centuries, filled in by impossible stories of + magical flight by witches, wizards, and the like—imagination was + fertile in the dark ages, but the ban of the church was on all attempt at + scientific development, especially in such a matter as the conquest of the + air. Yet there were observers of nature who argued that since birds could + raise themselves by flapping their wings, man had only to make suitable + wings, flap them, and he too would fly. As early as the thirteenth century + Roger Bacon, the scientific friar of unbounded inquisitiveness and not a + little real genius, announced that there could be made 'some flying + instrument, so that a man sitting in the middle and turning some mechanism + may put in motion some artificial wings which may beat the air like a bird + flying.' But being a cautious man, with a natural dislike for being burnt + at the stake as a necromancer through having put forward such a dangerous + theory, Roger added, 'not that I ever knew a man who had such an + instrument, but I am particularly acquainted with the man who contrived + one.' This might have been a lame defence if Roger had been brought to + trial as addicted to black arts; he seems to have trusted to the + inadmissibility of hearsay evidence. + </p> + <p> + Some four centuries later there was published a book entitled Perugia + Augusta, written by one C. Crispolti of Perugia—the date of the work + in question is 1648. In it is recorded that 'one day, towards the close of + the fifteenth century, whilst many of the principal gentry had come to + Perugia to honour the wedding of Giovanni Paolo Baglioni, and some lancers + were riding down the street by his palace, Giovanni Baptisti Danti + unexpectedly and by means of a contrivance of wings that he had + constructed proportionate to the size of his body took off from the top of + a tower near by, and with a horrible hissing sound flew successfully + across the great Piazza, which was densely crowded. But (oh, horror of an + unexpected accident!) he had scarcely flown three hundred paces on his way + to a certain point when the mainstay of the left wing gave way, and, being + unable to support himself with the right alone, he fell on a roof and was + injured in consequence. Those who saw not only this flight, but also the + wonderful construction of the framework of the wings, said—and + tradition bears them out—that he several times flew over the waters + of Lake Thrasimene to learn how he might gradually come to earth. But, + notwithstanding his great genius, he never succeeded.' + </p> + <p> + This reads circumstantially enough, but it may be borne in mind that the + date of writing is more than half a century later than the time of the + alleged achievement—the story had had time to round itself out. + Danti, however, is mentioned by a number of writers, one of whom states + that the failure of his experiment was due to the prayers of some + individual of a conservative turn of mind, who prayed so vigorously that + Danti fell appropriately enough on a church and injured himself to such an + extent as to put an end to his flying career. That Danti experimented, + there is little doubt, in view of the volume of evidence on the point, but + the darkness of the Middle Ages hides the real truth as to the results of + his experiments. If he had actually flown over Thrasimene, as alleged, + then in all probability both Napoleon and Wellington would have had air + scouts at Waterloo. + </p> + <p> + Danti's story may be taken as fact or left as fable, and with it the + period of legend or vague statement may be said to end—the rest is + history, both of genuine experimenters and of charlatans. Such instances + of legend as are given here are not a tithe of the whole, but there is + sufficient in the actual history of flight to bar out more than this brief + mention of the legends, which, on the whole, go farther to prove man's + desire to fly than his study and endeavour to solve the problems of the + air. + </p> + <p> + <a name="link2H_4_0004" id="link2H_4_0004"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + II. EARLY EXPERIMENTS + </h2> + <p> + So far, the stories of the development of flight are either legendary or + of more or less doubtful authenticity, even including that of Danti, who, + although a man of remarkable attainments in more directions than that of + attempted flight, suffers—so far as reputation is concerned—from + the inexactitudes of his chroniclers; he may have soared over Thrasimene, + as stated, or a mere hop with an ineffectual glider may have grown with + the years to a legend of gliding flight. So far, too, there is no evidence + of the study that the conquest of the air demanded; such men as made + experiments either launched themselves in the air from some height with + made-up wings or other apparatus, and paid the penalty, or else + constructed some form of machine which would not leave the earth, and then + gave up. Each man followed his own way, and there was no attempt—without + the printing press and the dissemination of knowledge there was little + possibility of attempt—on the part of any one to benefit by the + failures of others. + </p> + <p> + Legend and doubtful history carries up to the fifteenth century, and then + came Leonardo da Vinci, first student of flight whose work endures to the + present day. The world knows da Vinci as artist; his age knew him as + architect, engineer, artist, and scientist in an age when science was a + single study, comprising all knowledge from mathematics to medicine. He + was, of course, in league with the devil, for in no other way could his + range of knowledge and observation be explained by his contemporaries; he + left a Treatise on the Flight of Birds in which are statements and + deductions that had to be rediscovered when the Treatise had been + forgotten—da Vinci anticipated modern knowledge as Plato anticipated + modern thought, and blazed the first broad trail toward flight. + </p> + <p> + One Cuperus, who wrote a Treatise on the Excellence of Man, asserted that + da Vinci translated his theories into practice, and actually flew, but the + statement is unsupported. That he made models, especially on the + helicopter principle, is past question; these were made of paper and wire, + and actuated by springs of steel wire, which caused them to lift + themselves in the air. It is, however, in the theories which he put + forward that da Vinci's investigations are of greatest interest; these + prove him a patient as well as a keen student of the principles of flight, + and show that his manifold activities did not prevent him from devoting + some lengthy periods to observations of bird flight. + </p> + <p> + 'A bird,' he says in his Treatise, 'is an instrument working according to + mathematical law, which instrument it is within the capacity of man to + reproduce with all its movements, but not with a corresponding degree of + strength, though it is deficient only in power of maintaining equilibrium. + We may say, therefore, that such an instrument constructed by man is + lacking in nothing except the life of the bird, and this life must needs + be supplied from that of man. The life which resides in the bird's members + will, without doubt, better conform to their needs than will that of a man + which is separated from them, and especially in the almost imperceptible + movements which produce equilibrium. But since we see that the bird is + equipped for many apparent varieties of movement, we are able from this + experience to deduce that the most rudimentary of these movements will be + capable of being comprehended by man's understanding, and that he will to + a great extent be able to provide against the destruction of that + instrument of which he himself has become the living principle and the + propeller.' + </p> + <p> + In this is the definite belief of da Vinci that man is capable of flight, + together with a far more definite statement of the principles by which + flight is to be achieved than any which had preceded it—and for that + matter, than many that have succeeded it. Two further extracts from his + work will show the exactness of his observations:— + </p> + <p> + 'When a bird which is in equilibrium throws the centre of resistance of + the wings behind the centre of gravity, then such a bird will descend with + its head downward. This bird which finds itself in equilibrium shall have + the centre of resistance of the wings more forward than the bird's centre + of gravity; then such a bird will fall with its tail turned toward the + earth.' + </p> + <p> + And again: 'A man, when flying, shall be free from the waist up, that he + may be able to keep himself in equilibrium as he does in a boat, so that + the centre of his gravity and of the instrument may set itself in + equilibrium and change when necessity requires it to the changing of the + centre of its resistance.' + </p> + <p> + Here, in this last quotation, are the first beginnings of the inherent + stability which proved so great an advance in design, in this twentieth + century. But the extracts given do not begin to exhaust the range of da + Vinci's observations and deductions. With regard to bird flight, he + observed that so long as a bird keeps its wings outspread it cannot fall + directly to earth, but must glide down at an angle to alight—a small + thing, now that the principle of the plane in opposition to the air is + generally grasped, but da Vinci had to find it out. From observation he + gathered how a bird checks its own speed by opposing tail and wing surface + to the direction of flight, and thus alights at the proper 'landing + speed.' He proved the existence of upward air currents by noting how a + bird takes off from level earth with wings outstretched and motionless, + and, in order to get an efficient substitute for the natural wing, he + recommended that there be used something similar to the membrane of the + wing of a bat—from this to the doped fabric of an aeroplane wing is + but a small step, for both are equally impervious to air. Again, da Vinci + recommended that experiments in flight be conducted at a good height from + the ground, since, if equilibrium be lost through any cause, the height + gives time to regain it. This recommendation, by the way, received ample + support in the training areas of war pilots. + </p> + <p> + Man's muscles, said da Vinci, are fully sufficient to enable him to fly, + for the larger birds, he noted, employ but a small part of their strength + in keeping themselves afloat in the air—by this theory he attempted + to encourage experiment, just as, when his time came, Borelli reached the + opposite conclusion and discouraged it. That Borelli was right—so + far—and da Vinci wrong, detracts not at all from the repute of the + earlier investigator, who had but the resources of his age to support + investigations conducted in the spirit of ages after. + </p> + <p> + His chief practical contributions to the science of flight—apart + from numerous drawings which have still a value—are the helicopter + or lifting screw, and the parachute. The former, as already noted, he made + and proved effective in model form, and the principle which he + demonstrated is that of the helicopter of to-day, on which sundry + experimenters work spasmodically, in spite of the success of the plane + with its driving propeller. As to the parachute, the idea was doubtless + inspired by observation of the effect a bird produced by pressure of its + wings against the direction of flight. + </p> + <p> + Da Vinci's conclusions, and his experiments, were forgotten easily by most + of his contemporaries; his Treatise lay forgotten for nearly four + centuries, overshadowed, mayhap, by his other work. There was, however, a + certain Paolo Guidotti of Lucca, who lived in the latter half of the + sixteenth century, and who attempted to carry da Vinci's theories—one + of them, at least, into practice. For this Guidotti, who was by profession + an artist and by inclination an investigator, made for himself wings, of + which the framework was of whalebone; these he covered with feathers, and + with them made a number of gliding flights, attaining considerable + proficiency. He is said in the end to have made a flight of about four + hundred yards, but this attempt at solving the problem ended on a house + roof, where Guidotti broke his thigh bone. After that, apparently, he gave + up the idea of flight, and went back to painting. + </p> + <p> + One other a Venetian architect named Veranzio, studied da Vinci's theory + of the parachute, and found it correct, if contemporary records and even + pictorial presentment are correct. Da Vinci showed his conception of a + parachute as a sort of inverted square bag; Veranzio modified this to a + 'sort of square sail extended by four rods of equal size and having four + cords attached at the corners,' by means of which 'a man could without + danger throw himself from the top of a tower or any high place. For though + at the moment there may be no wind, yet the effort of his falling will + carry up the wind, which the sail will hold, by which means he does not + fall suddenly but descends little by little. The size of the sail should + be measured to the man.' By this last, evidently, Veranzio intended to + convey that the sheet must be of such content as would enclose sufficient + air to support the weight of the parachutist. + </p> + <p> + Veranzio made his experiments about 1617-1618, but, naturally, they + carried him no farther than the mere descent to earth, and since a descent + is merely a descent, it is to be conjectured that he soon got tired of + dropping from high roofs, and took to designing architecture instead of + putting it to such a use. With the end of his experiments the work of da + Vinci in relation to flying became neglected for nearly four centuries. + </p> + <p> + Apart from these two experimenters, there is little to record in the + matter either of experiment or study until the seventeenth century. + Francis Bacon, it is true, wrote about flying in his Sylva Sylvarum, and + mentioned the subject in the New Atlantis, but, except for the insight + that he showed even in superficial mention of any specific subject, he + does not appear to have made attempt at serious investigation. 'Spreading + of Feathers, thin and close and in great breadth will likewise bear up a + great Weight,' says Francis, 'being even laid without Tilting upon the + sides.' But a lesser genius could have told as much, even in that age, and + though the great Sir Francis is sometimes adduced as one of the early + students of the problems of flight, his writings will not sustain the + reputation. + </p> + <p> + The seventeenth century, however, gives us three names, those of Borelli, + Lana, and Robert Hooke, all of which take definite place in the history of + flight. Borelli ranks as one of the great figures in the study of + aeronautical problems, in spite of erroneous deductions through which he + arrived at a purely negative conclusion with regard to the possibility of + human flight. + </p> + <p> + Borelli was a versatile genius. Born in 1608, he was practically + contemporary with Francesco Lana, and there is evidence that he either + knew or was in correspondence with many prominent members of the Royal + Society of Great Britain, more especially with John Collins, Dr Wallis, + and Henry Oldenburgh, the then Secretary of the Society. He was author of + a long list of scientific essays, two of which only are responsible for + his fame, viz., Theorice Medicaearum Planetarum, published in Florence, + and the better known posthumous De Motu Animalium. The first of these two + is an astronomical study in which Borelli gives evidence of an instinctive + knowledge of gravitation, though no definite expression is given of this. + The second work, De Motu Animalium, deals with the mechanical action of + the limbs of birds and animals and with a theory of the action of the + internal organs. A section of the first part of this work, called De + Volatu, is a study of bird flight; it is quite independent of Da Vinci's + earlier work, which had been forgotten and remained unnoticed until near + on the beginning of practical flight. + </p> + <p> + Marey, in his work, La Machine Animale, credits Borelli with the first + correct idea of the mechanism of flight. He says: 'Therefore we must be + allowed to render to the genius of Borelli the justice which is due to + him, and only claim for ourselves the merit of having furnished the + experimental demonstration of a truth already suspected.' In fact, all + subsequent studies on this subject concur in making Borelli the first + investigator who illustrated the purely mechanical theory of the action of + a bird's wings. + </p> + <p> + Borelli's study is divided into a series of propositions in which he + traces the principles of flight, and the mechanical actions of the wings + of birds. The most interesting of these are the propositions in which he + sets forth the method in which birds move their wings during flight and + the manner in which the air offers resistance to the stroke of the wing. + With regard to the first of these two points he says: 'When birds in + repose rest on the earth their wings are folded up close against their + flanks, but when wishing to start on their flight they first bend their + legs and leap into the air. Whereupon the joints of their wings are + straightened out to form a straight line at right angles to the lateral + surface of the breast, so that the two wings, outstretched, are placed, as + it were, like the arms of a cross to the body of the bird. Next, since the + wings with their feathers attached form almost a plane surface, they are + raised slightly above the horizontal, and with a most quick impulse beat + down in a direction almost perpendicular to the wing-plane, upon the + underlying air; and to so intense a beat the air, notwithstanding it to be + fluid, offers resistance, partly by reason of its natural inertia, which + seeks to retain it at rest, and partly because the particles of the air, + compressed by the swiftness of the stroke, resist this compression by + their elasticity, just like the hard ground. Hence the whole mass of the + bird rebounds, making a fresh leap through the air; whence it follows that + flight is simply a motion composed of successive leaps accomplished + through the air. And I remark that a wing can easily beat the air in a + direction almost perpendicular to its plane surface, although only a + single one of the corners of the humerus bone is attached to the scapula, + the whole extent of its base remaining free and loose, while the greater + transverse feathers are joined to the lateral skin of the thorax. + Nevertheless the wing can easily revolve about its base like unto a fan. + Nor are there lacking tendon ligaments which restrain the feathers and + prevent them from opening farther, in the same fashion that sheets hold in + the sails of ships. No less admirable is nature's cunning in unfolding and + folding the wings upwards, for she folds them not laterally, but by moving + upwards edgewise the osseous parts wherein the roots of the feathers are + inserted; for thus, without encountering the air's resistance the upward + motion of the wing surface is made as with a sword, hence they can be + uplifted with but small force. But thereafter when the wings are twisted + by being drawn transversely and by the resistance of the air, they are + flattened as has been declared and will be made manifest hereafter.' + </p> + <p> + Then with reference to the resistance to the air of the wings he explains: + 'The air when struck offers resistance by its elastic virtue through which + the particles of the air compressed by the wing-beat strive to expand + again. Through these two causes of resistance the downward beat of the + wing is not only opposed, but even caused to recoil with a reflex + movement; and these two causes of resistance ever increase the more the + down stroke of the wing is maintained and accelerated. On the other hand, + the impulse of the wing is continuously diminished and weakened by the + growing resistance. Hereby the force of the wing and the resistance become + balanced; so that, manifestly, the air is beaten by the wing with the same + force as the resistance to the stroke.' + </p> + <p> + He concerns himself also with the most difficult problem that confronts + the flying man of to-day, namely, landing effectively, and his remarks on + this subject would be instructive even to an air pilot of these days: 'Now + the ways and means by which the speed is slackened at the end of a flight + are these. The bird spreads its wings and tail so that their concave + surfaces are perpendicular to the direction of motion; in this way, the + spreading feathers, like a ship's sail, strike against the still air, + check the speed, and so that most of the impetus may be stopped, the wings + are flapped quickly and strongly forward, inducing a contrary motion, so + that the bird absolutely or very nearly stops.' + </p> + <p> + At the end of his study Borelli came to a conclusion which militated + greatly against experiment with any heavier-than-air apparatus, until well + on into the nineteenth century, for having gone thoroughly into the + subject of bird flight he states distinctly in his last proposition on the + subject that 'It is impossible that men should be able to fly craftily by + their own strength.' This statement, of course, remains true up to the + present day for no man has yet devised the means by which he can raise + himself in the air and maintain himself there by mere muscular effort. + </p> + <p> + From the time of Borelli up to the development of the steam engine it may + be said that flight by means of any heavier-than-air apparatus was + generally regarded as impossible, and apart from certain deductions which + a little experiment would have shown to be doomed to failure, this method + of flight was not followed up. It is not to be wondered at, when Borelli's + exaggerated estimate of the strength expended by birds in proportion to + their weight is borne in mind; he alleged that the motive force in birds' + wings is 10,000 times greater than the resistance of their weight, and + with regard to human flight he remarks:— + </p> + <p> + 'When, therefore, it is asked whether men may be able to fly by their own + strength, it must be seen whether the motive power of the pectoral muscles + (the strength of which is indicated and measured by their size) is + proportionately great, as it is evident that it must exceed the resistance + of the weight of the whole human body 10,000 times, together with the + weight of enormous wings which should be attached to the arms. And it is + clear that the motive power of the pectoral muscles in men is much less + than is necessary for flight, for in birds the bulk and weight of the + muscles for flapping the wings are not less than a sixth part of the + entire weight of the body. Therefore, it would be necessary that the + pectoral muscles of a man should weigh more than a sixth part of the + entire weight of his body; so also the arms, by flapping with the wings + attached, should be able to exert a power 10,000 times greater than the + weight of the human body itself. But they are far below such excess, for + the aforesaid pectoral muscles do not equal a hundredth part of the entire + weight of a man. Wherefore either the strength of the muscles ought to be + increased or the weight of the human body must be decreased, so that the + same proportion obtains in it as exists in birds. Hence it is deducted + that the Icarian invention is entirely mythical because impossible, for it + is not possible either to increase a man's pectoral muscles or to diminish + the weight of the human body; and whatever apparatus is used, although it + is possible to increase the momentum, the velocity or the power employed + can never equal the resistance; and therefore wing flapping by the + contraction of muscles cannot give out enough power to carry up the heavy + body of a man.' + </p> + <p> + It may be said that practically all the conclusions which Borelli reached + in his study were negative. Although contemporary with Lana, he perceived + the one factor which rendered Lana's project for flight by means of vacuum + globes an impossibility—he saw that no globe could be constructed + sufficiently light for flight, and at the same time sufficiently strong to + withstand the pressure of the outside atmosphere. He does not appear to + have made any experiments in flying on his own account, having, as he + asserts most definitely, no faith in any invention designed to lift man + from the surface of the earth. But his work, from which only the foregoing + short quotations can be given, is, nevertheless, of indisputable value, + for he settled the mechanics of bird flight, and paved the way for those + later investigators who had, first, the steam engine, and later the + internal combustion engine—two factors in mechanical flight which + would have seemed as impossible to Borelli as would wireless telegraphy to + a student of Napoleonic times. On such foundations as his age afforded + Borelli built solidly and well, so that he ranks as one of the greatest—if + not actually the greatest—of the investigators into this subject + before the age of steam. + </p> + <p> + The conclusion, that 'the motive force in birds' wings is apparently ten + thousand times greater than the resistance of their weight,' is erroneous, + of course, but study of the translation from which the foregoing excerpt + is taken will show that the error detracts very little from the value of + the work itself. Borelli sets out very definitely the mechanism of flight, + in such fashion that he who runs may read. His reference to 'the use of a + large vessel,' etc., concerns the suggestion made by Francesco Lana, who + antedated Borelli's publication of De Motu Animalium by some ten years + with his suggestion for an 'aerial ship,' as he called it. Lana's mind + shows, as regards flight, a more imaginative twist; Borelli dived down + into first causes, and reached mathematical conclusions; Lana conceived a + theory and upheld it—theoretically, since the manner of his life + precluded experiment. + </p> + <p> + Francesco Lana, son of a noble family, was born in 1631; in 1647 he was + received as a novice into the Society of Jesus at Rome, and remained a + pious member of the Jesuit society until the end of his life. He was + greatly handicapped in his scientific investigations by the vows of + poverty which the rules of the Order imposed on him. He was more scientist + than priest all his life; for two years he held the post of Professor of + Mathematics at Ferrara, and up to the time of his death, in 1687, he spent + by far the greater part of his time in scientific research, He had the + dubious advantage of living in an age when one man could cover the whole + range of science, and this he seems to have done very thoroughly. There + survives an immense work of his entitled, Magisterium Naturae et Artis, + which embraces the whole field of scientific knowledge as that was + developed in the period in which Lana lived. In an earlier work of his, + published in Brescia in 1670, appears his famous treatise on the aerial + ship, a problem which Lana worked out with thoroughness. He was unable to + make practical experiments, and thus failed to perceive the one + insuperable drawback to his project—of which more anon. + </p> + <p> + Only extracts from the translation of Lana's work can be given here, but + sufficient can be given to show fully the means by which he designed to + achieve the conquest of the air. He begins by mention of the celebrated + pigeon of Archytas the Philosopher, and advances one or two theories with + regard to the way in which this mechanical bird was constructed, and then + he recites, apparently with full belief in it, the fable of Regiomontanus + and the eagle that he is said to have constructed to accompany Charles V. + on his entry into Nuremberg. In fact, Lana starts his work with a study of + the pioneers of mechanical flying up to his own time, and then outlines + his own devices for the construction of mechanical birds before proceeding + to detail the construction of the aerial ship. Concerning primary + experiments for this he says:— + </p> + <p> + 'I will, first of all, presuppose that air has weight owing to the vapours + and halations which ascend from the earth and seas to a height of many + miles and surround the whole of our terraqueous globe; and this fact will + not be denied by philosophers, even by those who may have but a + superficial knowledge, because it can be proven by exhausting, if not all, + at any rate the greater part of, the air contained in a glass vessel, + which, if weighed before and after the air has been exhausted, will be + found materially reduced in weight. Then I found out how much the air + weighed in itself in the following manner. I procured a large vessel of + glass, whose neck could be closed or opened by means of a tap, and holding + it open I warmed it over a fire, so that the air inside it becoming + rarified, the major part was forced out; then quickly shutting the tap to + prevent the re-entry I weighed it; which done, I plunged its neck in + water, resting the whole of the vessel on the surface of the water, then + on opening the tap the water rose in the vessel and filled the greater + part of it. I lifted the neck out of the water, released the water + contained in the vessel, and measured and weighed its quantity and + density, by which I inferred that a certain quantity of air had come out + of the vessel equal in bulk to the quantity of water which had entered to + refill the portion abandoned by the air. I again weighed the vessel, after + I had first of all well dried it free of all moisture, and found it + weighed one ounce more whilst it was full of air than when it was + exhausted of the greater part, so that what it weighed more was a quantity + of air equal in volume to the water which took its place. The water + weighed 640 ounces, so I concluded that the weight of air compared with + that of water was 1 to 640—that is to say, as the water which filled + the vessel weighed 640 ounces, so the air which filled the same vessel + weighed one ounce.' + </p> + <p> + Having thus detailed the method of exhausting air from a vessel, Lana goes + on to assume that any large vessel can be entirely exhausted of nearly all + the air contained therein. Then he takes Euclid's proposition to the + effect that the superficial area of globes increases in the proportion of + the square of the diameter, whilst the volume increases in the proportion + of the cube of the same diameter, and he considers that if one only + constructs the globe of thin metal, of sufficient size, and exhausts the + air in the manner that he suggests, such a globe will be so far lighter + than the surrounding atmosphere that it will not only rise, but will be + capable of lifting weights. Here is Lana's own way of putting it:— + </p> + <p> + 'But so that it may be enabled to raise heavier weights and to lift men in + the air, let us take double the quantity of copper, 1,232 square feet, + equal to 308 lbs. of copper; with this double quantity of copper we could + construct a vessel of not only double the capacity, but of four times the + capacity of the first, for the reason shown by my fourth supposition. + Consequently the air contained in such a vessel will be 718 lbs. 4 2/3 + ounces, so that if the air be drawn out of the vessel it will be 410 lbs. + 4 2/3 ounces lighter than the same volume of air, and, consequently, will + be enabled to lift three men, or at least two, should they weigh more than + eight pesi each. It is thus manifest that the larger the ball or vessel is + made, the thicker and more solid can the sheets of copper be made, + because, although the weight will increase, the capacity of the vessel + will increase to a greater extent and with it the weight of the air + therein, so that it will always be capable to lift a heavier weight. From + this it can be easily seen how it is possible to construct a machine + which, fashioned like unto a ship, will float on the air.' + </p> + <p> + With four globes of these dimensions Lana proposed to make an aerial ship + of the fashion shown in his quaint illustration. He is careful to point + out a method by which the supporting globes for the aerial ship may be + entirely emptied of air; (this is to be done by connecting to each globe a + tube of copper which is 'at least a length of 47 modern Roman palm).' A + small tap is to close this tube at the end nearest the globe, and then + vessel and tube are to be filled with water, after which the tube is to be + immersed in water and the tap opened, allowing the water to run out of the + vessel, while no air enters. The tap is then closed before the lower end + of the tube is removed from the water, leaving no air at all in the globe + or sphere. Propulsion of this airship was to be accomplished by means of + sails, and also by oars. + </p> + <p> + Lana antedated the modern propeller, and realised that the air would offer + enough resistance to oars or paddle to impart motion to any vessel + floating in it and propelled by these means, although he did not realise + the amount of pressure on the air which would be necessary to accomplish + propulsion. As a matter of fact, he foresaw and provided against + practically all the difficulties that would be encountered in the working, + as well as the making, of the aerial ship, finally coming up against what + his religious training made an insuperable objection. This, again, is best + told in his own words:— + </p> + <p> + 'Other difficulties I do not foresee that could prevail against this + invention, save one only, which to me seems the greatest of them all, and + that is that God would surely never allow such a machine to be successful, + since it would create many disturbances in the civil and political + governments of mankind.' + </p> + <p> + He ends by saying that no city would be proof against surprise, while the + aerial ship could set fire to vessels at sea, and destroy houses, + fortresses, and cities by fire balls and bombs. In fact, at the end of his + treatise on the subject, he furnishes a pretty complete resume of the + activities of German Zeppelins. + </p> + <p> + As already noted, Lana himself, owing to his vows of poverty, was unable + to do more than put his suggestions on paper, which he did with a + thoroughness that has procured him a place among the really great pioneers + of flying. + </p> + <p> + It was nearly 200 years before any attempt was made to realise his + project; then, in 1843, M. Marey Monge set out to make the globes and the + ship as Lana detailed them. Monge's experiments cost him the sum of 25,000 + francs 75 centimes, which he expended purely from love of scientific + investigation. He chose to make his globes of brass, about.004 in + thickness, and weighing 1.465 lbs. to the square yard. Having made his + sphere of this metal, he lined it with two thicknesses of tissue paper, + varnished it with oil, and set to work to empty it of air. This, however, + he never achieved, for such metal is incapable of sustaining the pressure + of the outside air, as Lana, had he had the means to carry out + experiments, would have ascertained. M. Monge's sphere could never be + emptied of air sufficiently to rise from the earth; it ended in the + melting-pot, ignominiously enough, and all that Monge got from his + experiment was the value of the scrap metal and the satisfaction of + knowing that Lana's theory could never be translated into practice. + </p> + <p> + Robert Hooke is less conspicuous than either Borelli or Lana; his work, + which came into the middle of the seventeenth century, consisted of + various experiments with regard to flight, from which emerged 'a Module, + which by the help of Springs and Wings, raised and sustained itself in the + air.' This must be reckoned as the first model flying machine which + actually flew, except for da Vinci's helicopters; Hooke's model appears to + have been of the flapping-wing type—he attempted to copy the motion + of birds, but found from study and experiment that human muscles were not + sufficient to the task of lifting the human body. For that reason, he + says, 'I applied my mind to contrive a way to make artificial muscles,' + but in this he was, as he expresses it, 'frustrated of my expectations.' + Hooke's claim to fame rests mainly on his successful model; the rest of + his work is of too scrappy a nature to rank as a serious contribution to + the study of flight. + </p> + <p> + Contemporary with Hooke was one Allard, who, in France, undertook to + emulate the Saracen of Constantinople to a certain extent. Allard was a + tight-rope dancer who either did or was said to have done short gliding + flights—the matter is open to question—and finally stated that + he would, at St Germains, fly from the terrace in the king's presence. He + made the attempt, but merely fell, as did the Saracen some centuries + before, causing himself serious injury. Allard cannot be regarded as a + contributor to the development of aeronautics in any way, and is only + mentioned as typical of the way in which, up to the time of the Wright + brothers, flying was regarded. Even unto this day there are many who still + believe that, with a pair of wings, man ought to be able to fly, and that + the mathematical data necessary to effective construction simply do not + exist. This attitude was reasonable enough in an unlearned age, and Allard + was one—a little more conspicuous than the majority—among many + who made experiment in ignorance, with more or less danger to themselves + and without practical result of any kind. + </p> + <p> + The seventeenth century was not to end, however, without practical + experiment of a noteworthy kind in gliding flight. Among the recruits to + the ranks of pioneers was a certain Besnier, a locksmith of Sable, who + somewhere between 1675 and 1680 constructed a glider of which a crude + picture has come down to modern times. The apparatus, as will be seen, + consisted of two rods with hinged flaps, and the original designer of the + picture seems to have had but a small space in which to draw, since + obviously the flaps must have been much larger than those shown. Besnier + placed the rods on his shoulders, and worked the flaps by cords attached + to his hands and feet—the flaps opened as they fell, and closed as + they rose, so the device as a whole must be regarded as a sort of flapping + glider. Having by experiment proved his apparatus successful, Besnier + promptly sold it to a travelling showman of the period, and forthwith set + about constructing a second set, with which he made gliding flights of + considerable height and distance. Like Lilienthal, Besnier projected + himself into space from some height, and then, according to the + contemporary records, he was able to cross a river of considerable size + before coming to earth. It does not appear that he had any imitators, or + that any advantage whatever was taken of his experiments; the age was one + in which he would be regarded rather as a freak exhibitor than as a + serious student, and possibly, considering his origin and the sale of his + first apparatus to such a client, he regarded the matter himself as more + in the nature of an amusement than as a discovery. + </p> + <p> + Borelli, coming at the end of the century, proved to his own satisfaction + and that of his fellows that flapping wing flight was an impossibility; + the capabilities of the plane were as yet undreamed, and the prime mover + that should make the plane available for flight was deep in the womb of + time. Da Vinci's work was forgotten—flight was an impossibility, or + at best such a useless show as Besnier was able to give. + </p> + <p> + The eighteenth century was almost barren of experiment. Emanuel + Swedenborg, having invented a new religion, set about inventing a flying + machine, and succeeded theoretically, publishing the result of his + investigations as follows:— + </p> + <p> + 'Let a car or boat or some like object be made of light material such as + cork or bark, with a room within it for the operator. Secondly, in front + as well as behind, or all round, set a widely-stretched sail parallel to + the machine forming within a hollow or bend which could be reefed like the + sails of a ship. Thirdly, place wings on the sides, to be worked up and + down by a spiral spring, these wings also to be hollow below in order to + increase the force and velocity, take in the air, and make the resistance + as great as may be required. These, too, should be of light material and + of sufficient size; they should be in the shape of birds' wings, or the + sails of a windmill, or some such shape, and should be tilted obliquely + upwards, and made so as to collapse on the upward stroke and expand on the + downward. Fourth, place a balance or beam below, hanging down + perpendicularly for some distance with a small weight attached to its end, + pendent exactly in line with the centre of gravity; the longer this beam + is, the lighter must it be, for it must have the same proportion as the + well-known vectis or steel-yard. This would serve to restore the balance + of the machine if it should lean over to any of the four sides. Fifthly, + the wings would perhaps have greater force, so as to increase the + resistance and make the flight easier, if a hood or shield were placed + over them, as is the case with certain insects. Sixthly, when the sails + are expanded so as to occupy a great surface and much air, with a balance + keeping them horizontal, only a small force would be needed to move the + machine back and forth in a circle, and up and down. And, after it has + gained momentum to move slowly upwards, a slight movement and an even + bearing would keep it balanced in the air and would determine its + direction at will.' + </p> + <p> + The only point in this worthy of any note is the first device for + maintaining stability automatically—Swedenborg certainly scored a + point there. For the rest, his theory was but theory, incapable of being + put to practice—he does not appear to have made any attempt at + advance beyond the mere suggestion. + </p> + <p> + Some ten years before his time the state of knowledge with regard to + flying in Europe was demonstrated by an order granted by the King of + Portugal to Friar Lourenzo de Guzman, who claimed to have invented a + flying machine capable of actual flight. The order stated that 'In order + to encourage the suppliant to apply himself with zeal toward the + improvement of the new machine, which is capable of producing the effects + mentioned by him, I grant unto him the first vacant place in my College of + Barcelos or Santarem, and the first professorship of mathematics in my + University of Coimbra, with the annual pension of 600,000 reis during his + life.—Lisbon, 17th of March, 1709.' + </p> + <p> + What happened to Guzman when the non-existence of the machine was + discovered is one of the things that is well outside the province of + aeronautics. He was charlatan pure and simple, as far as actual flight was + concerned, though he had some ideas respecting the design of hot-air + balloons, according to Tissandier. (La Navigation Aerienne.) His flying + machine was to contain, among other devices, bellows to produce artificial + wind when the real article failed, and also magnets in globes to draw the + vessel in an upward direction and maintain its buoyancy. Some draughtsman, + apparently gifted with as vivid imagination as Guzman himself, has given + to the world an illustration of the hypothetical vessel; it bears some + resemblance to Lana's aerial ship, from which fact one draws obvious + conclusions. + </p> + <p> + A rather amusing claim to solving the problem of flight was made in the + middle of the eighteenth century by one Grimaldi, a 'famous and unique + Engineer' who, as a matter of actual fact, spent twenty years in + missionary work in India, and employed the spare time that missionary work + left him in bringing his invention to a workable state. The invention is + described as a 'box which with the aid of clockwork rises in the air, and + goes with such lightness and strong rapidity that it succeeds in flying a + journey of seven leagues in an hour. It is made in the fashion of a bird; + the wings from end to end are 25 feet in extent. The body is composed of + cork, artistically joined together and well fastened with metal wire, + covered with parchment and feathers. The wings are made of catgut and + whalebone, and covered also with the same parchment and feathers, and each + wing is folded in three seams. In the body of the machine are contained + thirty wheels of unique work, with two brass globes and little chains + which alternately wind up a counterpoise; with the aid of six brass vases, + full of a certain quantity of quicksilver, which run in some pulleys, the + machine is kept by the artist in due equilibrium and balance. By means, + then, of the friction between a steel wheel adequately tempered and a very + heavy and surprising piece of lodestone, the whole is kept in a regulated + forward movement, given, however, a right state of the winds, since the + machine cannot fly so much in totally calm weather as in stormy. This + prodigious machine is directed and guided by a tail seven palmi long, + which is attached to the knees and ankles of the inventor by leather + straps; by stretching out his legs, either to the right or to the left, he + moves the machine in whichever direction he pleases.... The machine's + flight lasts only three hours, after which the wings gradually close + themselves, when the inventor, perceiving this, goes down gently, so as to + get on his own feet, and then winds up the clockwork and gets himself + ready again upon the wings for the continuation of a new flight. He + himself told us that if by chance one of the wheels came off or if one of + the wings broke, it is certain he would inevitably fall rapidly to the + ground, and, therefore, he does not rise more than the height of a tree or + two, as also he only once put himself in the risk of crossing the sea, and + that was from Calais to Dover, and the same morning he arrived in London.' + </p> + <p> + And yet there are still quite a number of people who persist in stating + that Bleriot was the first man to fly across the Channel! + </p> + <p> + A study of the development of the helicopter principle was published in + France in 1868, when the great French engineer Paucton produced his + Theorie de la Vis d'Archimede. For some inexplicable reason, Paucton was + not satisfied with the term 'helicopter,' but preferred to call it a + 'pterophore,' a name which, so far as can be ascertained, has not been + adopted by any other writer or investigator. Paucton stated that, since a + man is capable of sufficient force to overcome the weight of his own body, + it is only necessary to give him a machine which acts on the air 'with all + the force of which it is capable and at its utmost speed,' and he will + then be able to lift himself in the air, just as by the exertion of all + his strength he is able to lift himself in water. 'It would seem,' says + Paucton, 'that in the pterophore, attached vertically to a carriage, the + whole built lightly and carefully assembled, he has found something that + will give him this result in all perfection. In construction, one would be + careful that the machine produced the least friction possible, and + naturally it ought to produce little, as it would not be at all + complicated. The new Daedalus, sitting comfortably in his carriage, would + by means of a crank give to the pterophore a suitable circular (or + revolving) speed. This single pterophore would lift him vertically, but in + order to move horizontally he should be supplied with a tail in the shape + of another pterophore. When he wished to stop for a little time, valves + fixed firmly across the end of the space between the blades would + automatically close the openings through which the air flows, and change + the pterophore into an unbroken surface which would resist the flow of air + and retard the fall of the machine to a considerable degree.' + </p> + <p> + The doctrine thus set forth might appear plausible, but it is based on the + common misconception that all the force which might be put into the + helicopter or 'pterophore' would be utilised for lifting or propelling the + vehicle through the air, just as a propeller uses all its power to drive a + ship through water. But, in applying such a propelling force to the air, + most of the force is utilised in maintaining aerodynamic support—as + a matter of fact, more force is needed to maintain this support than the + muscle of man could possibly furnish to a lifting screw, and even if the + helicopter were applied to a full-sized, engine-driven air vehicle, the + rate of ascent would depend on the amount of surplus power that could be + carried. For example, an upward lift of 1,000 pounds from a propeller 15 + feet in diameter would demand an expenditure of 50 horse-power under the + best possible conditions, and in order to lift this load vertically + through such atmospheric pressure as exists at sea-level or thereabouts, + an additional 20 horsepower would be required to attain a rate of 11 feet + per second—50 horse-power must be continually provided for the mere + support of the load, and the additional 20 horse-power must be continually + provided in order to lift it. Although, in model form, there is nothing + quite so strikingly successful as the helicopter in the range of flying + machines, yet the essential weight increases so disproportionately to the + effective area that it is necessary to go but very little beyond model + dimensions for the helicopter to become quite ineffective. + </p> + <p> + That is not to say that the lifting screw must be totally ruled out so far + as the construction of aircraft is concerned. Much is still empirical, so + far as this branch of aeronautics is concerned, and consideration of the + structural features of a propeller goes to show that the relations of + essential weight and effective area do not altogether apply in practice as + they stand in theory. Paucton's dream, in some modified form, may yet + become reality—it is only so short a time ago as 1896 that Lord + Kelvin stated he had not the smallest molecule of faith in aerial + navigation, and since the whole history of flight consists in proving the + impossible possible, the helicopter may yet challenge the propelled plane + surface for aerial supremacy. + </p> + <p> + It does not appear that Paucton went beyond theory, nor is there in his + theory any advance toward practical flight—da Vinci could have told + him as much as he knew. He was followed by Meerwein, who invented an + apparatus apparently something between a flapping wing machine and a + glider, consisting of two wings, which were to be operated by means of a + rod; the venturesome one who would fly by means of this apparatus had to + lie in a horizontal position beneath the wings to work the rod. Meerwein + deserves a place of mention, however, by reason of his investigations into + the amount of surface necessary to support a given weight. Taking that + weight at 200 pounds—which would allow for the weight of a man and a + very light apparatus—he estimated that 126 square feet would be + necessary for support. His pamphlet, published at Basle in 1784, shows him + to have been a painstaking student of the potentialities of flight. + </p> + <p> + Jean-Pierre Blanchard, later to acquire fame in connection with balloon + flight, conceived and described a curious vehicle, of which he even + announced trials as impending. His trials were postponed time after time, + and it appears that he became convinced in the end of the futility of his + device, being assisted to such a conclusion by Lalande, the astronomer, + who repeated Borelli's statement that it was impossible for man ever to + fly by his own strength. This was in the closing days of the French + monarchy, and the ascent of the Montgolfiers' first hot-air balloon in + 1783—which shall be told more fully in its place—put an end to + all French experiments with heavier-than-air apparatus, though in England + the genius of Cayley was about to bud, and even in France there were those + who understood that ballooning was not true flight. + </p> + <p> + <a name="link2H_4_0005" id="link2H_4_0005"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + III. SIR GEORGE CAYLEY—THOMAS WALKER + </h2> + <p> + On the fifth of June, 1783, the Montgolfiers' hot-air balloon rose at + Versailles, and in its rising divided the study of the conquest of the air + into two definite parts, the one being concerned with the propulsion of + gas lifted, lighter-than-air vehicles, and the other being crystallised in + one sentence by Sir George Cayley: 'The whole problem,' he stated, 'is + confined within these limits, viz.: to make a surface support a given + weight by the application of power to the resistance of the air.' For + about ten years the balloon held the field entirely, being regarded as the + only solution of the problem of flight that man could ever compass. So + definite for a time was this view on the eastern side of the Channel that + for some years practically all the progress that was made in the + development of power-driven planes was made in Britain. + </p> + <p> + In 1800 a certain Dr Thomas Young demonstrated that certain curved + surfaces suspended by a thread moved into and not away from a horizontal + current of air, but the demonstration, which approaches perilously near to + perpetual motion if the current be truly horizontal, has never been + successfully repeated, so that there is more than a suspicion that Young's + air-current was NOT horizontal. Others had made and were making + experiments on the resistance offered to the air by flat surfaces, when + Cayley came to study and record, earning such a place among the pioneers + as to win the title of 'father of British aeronautics.' + </p> + <p> + Cayley was a man in advance of his time, in many ways. Of independent + means, he made the grand tour which was considered necessary to the + education of every young man of position, and during this excursion he was + more engaged in studies of a semi-scientific character than in the + pursuits that normally filled such a period. His various writings prove + that throughout his life aeronautics was the foremost subject in his mind; + the Mechanic's Magazine, Nicholson's Journal, the Philosophical Magazine, + and other periodicals of like nature bear witness to Cayley's continued + research into the subject of flight. He approached the subject after the + manner of the trained scientist, analysing the mechanical properties of + air under chemical and physical action. Then he set to work to ascertain + the power necessary for aerial flight, and was one of the first to + enunciate the fallacy of the hopes of successful flight by means of the + steam engine of those days, owing to the fact that it was impossible to + obtain a given power with a given weight. + </p> + <p> + Yet his conclusions on this point were not altogether negative, for as + early as 1810 he stated that he could construct a balloon which could + travel with passengers at 20 miles an hour—he was one of the first + to consider the possibilities of applying power to a balloon. Nearly + thirty years later—in 1837—he made the first attempt at + establishing an aeronautical society, but at that time the power-driven + plane was regarded by the great majority as an absurd dream of more or + less mad inventors, while ballooning ranked on about the same level as + tight-rope walking, being considered an adjunct to fairs and fetes, more a + pastime than a study. + </p> + <p> + Up to the time of his death, in 1857, Cayley maintained his study of + aeronautical matters, and there is no doubt whatever that his work went + far in assisting the solution of the problem of air conquest. His + principal published work, a monograph entitled Aerial Navigation, has been + republished in the admirable series of 'Aeronautical Classics' issued by + the Royal Aeronautical Society. He began this work by pointing out the + impossibility of flying by means of attached wings, an impossibility due + to the fact that, while the pectoral muscles of a bird account for more + than two-thirds of its whole muscular strength, in a man the muscles + available for flying, no matter what mechanism might be used, would not + exceed one-tenth of his total strength. + </p> + <p> + Cayley did not actually deny the possibility of a man flying by muscular + effort, however, but stated that 'the flight of a strong man by great + muscular exertion, though a curious and interesting circumstance, inasmuch + as it will probably be the means of ascertaining finis power and supplying + the basis whereon to improve it, would be of little use.' + </p> + <p> + From this he goes on to the possibility of using a Boulton and Watt steam + engine to develop the power necessary for flight, and in this he saw a + possibility of practical result. It is worthy of note that in this + connection he made mention of the forerunner of the modern internal + combustion engine; 'The French,' he said, 'have lately shown the great + power produced by igniting inflammable powders in closed vessels, and + several years ago an engine was made to work in this country in a similar + manner by inflammation of spirit of tar.' In a subsequent paragraph of his + monograph he anticipates almost exactly the construction of the Lenoir gas + engine, which came into being more than fifty-five years after his + monograph was published. + </p> + <p> + Certain experiments detailed in his work were made to ascertain the size + of the surface necessary for the support of any given weight. He accepted + a truism of to-day in pointing out that in any matters connected with + aerial investigation, theory and practice are as widely apart as the + poles. Inclined at first to favour the helicopter principle, he finally + rejected this in favour of the plane, with which he made numerous + experiments. During these, he ascertained the peculiar advantages of + curved surfaces, and saw the necessity of providing both vertical and + horizontal rudders in order to admit of side steering as well as the + control of ascent and descent, and for preserving equilibrium. He may be + said to have anticipated the work of Lilienthal and Pilcher, since he + constructed and experimented with a fixed surface glider. 'It was + beautiful,' he wrote concerning this, 'to see this noble white bird + sailing majestically from the top of a hill to any given point of the + plain below it with perfect steadiness and safety, according to the set of + its rudder, merely by its own weight, descending at an angle of about + eight degrees with the horizon.' + </p> + <p> + It is said that he once persuaded his gardener to trust himself in this + glider for a flight, but if Cayley himself ventured a flight in it he has + left no record of the fact. The following extract from his work, Aerial + Navigation, affords an instance of the thoroughness of his investigations, + and the concluding paragraph also shows his faith in the ultimate triumph + of mankind in the matter of aerial flight:— + </p> + <p> + 'The act of flying requires less exertion than from the appearance is + supposed. Not having sufficient data to ascertain the exact degree of + propelling power exerted by birds in the act of flying, it is uncertain + what degree of energy may be required in this respect for vessels of + aerial navigation; yet when we consider the many hundreds of miles of + continued flight exerted by birds of passage, the idea of its being only a + small effort is greatly corroborated. To apply the power of the first + mover to the greatest advantage in producing this effect is a very + material point. The mode universally adopted by Nature is the oblique waft + of the wing. We have only to choose between the direct beat overtaking the + velocity of the current, like the oar of a boat, or one applied like the + wing, in some assigned degree of obliquity to it. Suppose 35 feet per + second to be the velocity of an aerial vehicle, the oar must be moved with + this speed previous to its being able to receive any resistance; then if + it be only required to obtain a pressure of one-tenth of a lb. upon each + square foot it must exceed the velocity of the current 7.3 feet per + second. Hence its whole velocity must be 42.5 feet per second. Should the + same surface be wafted downward like a wing with the hinder edge inclined + upward in an angle of about 50 deg. 40 feet to the current it will + overtake it at a velocity of 3.5 feet per second; and as a slight unknown + angle of resistance generates a lb. pressure per square foot at this + velocity, probably a waft of a little more than 4 feet per second would + produce this effect, one-tenth part of which would be the propelling + power. The advantage of this mode of application compared with the former + is rather more than ten to one. + </p> + <p> + 'In continuing the general principles of aerial navigation, for the + practice of the art, many mechanical difficulties present themselves which + require a considerable course of skilfully applied experiments before they + can be overcome; but, to a certain extent, the air has already been made + navigable, and no one who has seen the steadiness with which weights to + the amount of ten stone (including four stone, the weight of the machine) + hover in the air can doubt of the ultimate accomplishment of this object.' + </p> + <p> + This extract from his work gives but a faint idea of the amount of + research for which Cayley was responsible. He had the humility of the true + investigator in scientific problems, and so far as can be seen was never + guilty of the great fault of so many investigators in this subject—that + of making claims which he could not support. He was content to do, and + pass after having recorded his part, and although nearly half a century + had to pass between the time of his death and the first actual flight by + means of power-driven planes, yet he may be said to have contributed very + largely to the solution of the problem, and his name will always rank high + in the roll of the pioneers of flight. + </p> + <p> + Practically contemporary with Cayley was Thomas Walker, concerning whom + little is known save that he was a portrait painter of Hull, where was + published his pamphlet on The Art of Flying in 1810, a second and + amplified edition being produced, also in Hull, in 1831. The pamphlet, + which has been reproduced in extenso in the Aeronautical Classics series + published by the Royal Aeronautical Society, displays a curious mixture of + the true scientific spirit and colossal conceit. Walker appears to have + been a man inclined to jump to conclusions, which carried him up to the + edge of discovery and left him vacillating there. + </p> + <p> + The study of the two editions of his pamphlet side by side shows that + their author made considerable advances in the practicability of his + designs in the 21 intervening years, though the drawings which accompany + the text in both editions fail to show anything really capable of flight. + The great point about Walker's work as a whole is its suggestiveness; he + did not hesitate to state that the 'art' of flying is as truly mechanical + as that of rowing a boat, and he had some conception of the necessary + mechanism, together with an absolute conviction that he knew all there was + to be known. 'Encouraged by the public,' he says, 'I would not abandon my + purpose of making still further exertions to advance and complete an art, + the discovery of the TRUE PRINCIPLES (the italics are Walker's own) of + which, I trust, I can with certainty affirm to be my own.' + </p> + <p> + The pamphlet begins with Walker's admiration of the mechanism of flight as + displayed by birds. 'It is now almost twenty years,' he says, 'since I was + first led to think, by the study of birds and their means of flying, that + if an artificial machine were formed with wings in exact imitation of the + mechanism of one of those beautiful living machines, and applied in the + very same way upon the air, there could be no doubt of its being made to + fly, for it is an axiom in philosophy that the same cause will ever + produce the same effect.' With this he confesses his inability to produce + the said effect through lack of funds, though he clothes this delicately + in the phrase 'professional avocations and other circumstances.' Owing to + this inability he published his designs that others might take advantage + of them, prefacing his own researches with a list of the very early + pioneers, and giving special mention to Friar Bacon, Bishop Wilkins, and + the Portuguese friar, De Guzman. But, although he seems to suggest that + others should avail themselves of his theoretical knowledge, there is a + curious incompleteness about the designs accompanying his work, and about + the work itself, which seems to suggest that he had more knowledge to + impart than he chose to make public—or else that he came very near + to complete solution of the problem of flight, and stayed on the threshold + without knowing it. + </p> + <p> + After a dissertation upon the history and strength of the condor, and on + the differences between the weights of birds, he says: 'The following + observations upon the wonderful difference in the weight of some birds, + with their apparent means of supporting it in their flight, may tend to + remove some prejudices against my plan from the minds of some of my + readers. The weight of the humming-bird is one drachm, that of the condor + not less than four stone. Now, if we reduce four stone into drachms we + shall find the condor is 14,336 times as heavy as the humming-bird. What + an amazing disproportion of weight! Yet by the same mechanical use of its + wings the condor can overcome the specific gravity of its body with as + much ease as the little humming-bird. But this is not all. We are informed + that this enormous bird possesses a power in its wings, so far exceeding + what is necessary for its own conveyance through the air, that it can take + up and fly away with a whole sheer in its talons, with as much ease as an + eagle would carry off, in the same manner, a hare or a rabbit. This we may + readily give credit to, from the known fact of our little kestrel and the + sparrow-hawk frequently flying off with a partridge, which is nearly three + times the weight of these rapacious little birds.' + </p> + <p> + After a few more observations he arrives at the following conclusion: 'By + attending to the progressive increase in the weight of birds, from the + delicate little humming-bird up to the huge condor, we clearly discover + that the addition of a few ounces, pounds, or stones, is no obstacle to + the art of flying; the specific weight of birds avails nothing, for by + their possessing wings large enough, and sufficient power to work them, + they can accomplish the means of flying equally well upon all the various + scales and dimensions which we see in nature. Such being a fact, in the + name of reason and philosophy why shall not man, with a pair of artificial + wings, large enough, and with sufficient power to strike them upon the + air, be able to produce the same effect?' + </p> + <p> + Walker asserted definitely and with good ground that muscular effort + applied without mechanism is insufficient for human flight, but he states + that if an aeronautical boat were constructed so that a man could sit in + it in the same manner as when rowing, such a man would be able to bring + into play his whole bodily strength for the purpose of flight, and at the + same time would be able to get an additional advantage by exerting his + strength upon a lever. At first he concluded there must be expansion of + wings large enough to resist in a sufficient degree the specific gravity + of whatever is attached to them, but in the second edition of his work he + altered this to 'expansion of flat passive surfaces large enough to reduce + the force of gravity so as to float the machine upon the air with the man + in it.' The second requisite is strength enough to strike the wings with + sufficient force to complete the buoyancy and give a projectile motion to + the machine. Given these two requisites, Walker states definitely that + flying must be accomplished simply by muscular exertion. 'If we are secure + of these two requisites, and I am very confident we are, we may calculate + upon the success of flight with as much certainty as upon our walking.' + </p> + <p> + Walker appears to have gained some confidence from the experiments of a + certain M. Degen, a watchmaker of Vienna, who, according to the Monthly + Magazine of September, 1809, invented a machine by means of which a person + might raise himself into the air. The said machine, according to the + magazine, was formed of two parachutes which might be folded up or + extended at pleasure, while the person who worked them was placed in the + centre. This account, however, was rather misleading, for the magazine + carefully avoided mention of a balloon to which the inventor fixed his + wings or parachutes. Walker, knowing nothing of the balloon, concluded + that Degen actually raised himself in the air, though he is doubtful of + the assertion that Degen managed to fly in various directions, especially + against the wind. + </p> + <p> + Walker, after considering Degen and all his works, proceeds to detail his + own directions for the construction of a flying machine, these being as + follows: 'Make a car of as light material as possible, but with sufficient + strength to support a man in it; provide a pair of wings about four feet + each in length; let them be horizontally expanded and fastened upon the + top edge of each side of the car, with two joints each, so as to admit of + a vertical motion to the wings, which motion may be effected by a man + sitting and working an upright lever in the middle of the car. Extend in + the front of the car a flat surface of silk, which must be stretched out + and kept fixed in a passive state; there must be the same fixed behind the + car; these two surfaces must be perfectly equal in length and breadth and + large enough to cover a sufficient quantity of air to support the whole + weight as nearly in equilibrium as possible, thus we shall have a great + sustaining power in those passive surfaces and the active wings will + propel the car forward.' + </p> + <p> + A description of how to launch this car is subsequently given: 'It becomes + necessary,' says the theorist, 'that I should give directions how it may + be launched upon the air, which may be done by various means; perhaps the + following method may be found to answer as well as any: Fix a poll upright + in the earth, about twenty feet in height, with two open collars to admit + another poll to slide upwards through them; let there be a sliding + platform made fast upon the top of the sliding poll; place the car with a + man in it upon the platform, then raise the platform to the height of + about thirty feet by means of the sliding poll, let the sliding poll and + platform suddenly fall down, the car will then be left upon the air, and + by its pressing the air a projectile force will instantly propel the car + forward; the man in the car must then strike the active wings briskly upon + the air, which will so increase the projectile force as to become superior + to the force of gravitation, and if he inclines his weight a little + backward, the projectile impulse will drive the car forward in an + ascending direction. When the car is brought to a sufficient altitude to + clear the tops of hills, trees, buildings, etc., the man, by sitting a + little forward on his seat, will then bring the wings upon a horizontal + plane, and by continuing the action of the wings he will be impelled + forward in that direction. To descend, he must desist from striking the + wings, and hold them on a level with their joints; the car will then + gradually come down, and when it is within five or six feet of the ground + the man must instantly strike the wings downwards, and sit as far back as + he can; he will by this means check the projectile force, and cause the + car to alight very gently with a retrograde motion. The car, when up in + the air, may be made to turn to the right or to the left by forcing out + one of the fins, having one about eighteen inches long placed vertically + on each side of the car for that purpose, or perhaps merely by the man + inclining the weight of his body to one side.' + </p> + <p> + Having stated how the thing is to be done, Walker is careful to explain + that when it is done there will be in it some practical use, notably in + respect of the conveyance of mails and newspapers, or the saving of life + at sea, or for exploration, etc. It might even reduce the number of horses + kept by man for his use, by means of which a large amount of land might be + set free for the growth of food for human consumption. + </p> + <p> + At the end of his work Walker admits the idea of steam power for driving a + flying machine in place of simple human exertion, but he, like Cayley, saw + a drawback to this in the weight of the necessary engine. On the whole, he + concluded, navigation of the air by means of engine power would be mostly + confined to the construction of navigable balloons. + </p> + <p> + As already noted, Walker's work is not over practical, and the foregoing + extract includes the most practical part of it; the rest is a series of + dissertations on bird flight, in which, evidently, the portrait painter's + observations were far less thorough than those of da Vinci or Borelli. + Taken on the whole, Walker was a man with a hobby; he devoted to it much + time and thought, but it remained a hobby, nevertheless. His observations + have proved useful enough to give him a place among the early students of + flight, but a great drawback to his work is the lack of practical + experiment, by means of which alone real advance could be made; for, as + Cayley admitted, theory and practice are very widely separated in the + study of aviation, and the whole history of flight is a matter of + unexpected results arising from scarcely foreseen causes, together with + experiment as patient as daring. + </p> + <p> + <a name="link2H_4_0006" id="link2H_4_0006"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + IV. THE MIDDLE NINETEENTH CENTURY + </h2> + <p> + Both Cayley and Walker were theorists, though Cayley supported his + theoretical work with enough of practice to show that he studied along + right lines; a little after his time there came practical men who brought + to being the first machine which actually flew by the application of + power. Before their time, however, mention must be made of the work of + George Pocock of Bristol, who, somewhere about 1840 invented what was + described as a 'kite carriage,' a vehicle which carried a number of + persons, and obtained its motive power from a large kite. It is on record + that, in the year 1846 one of these carriages conveyed sixteen people from + Bristol to London. Another device of Pocock's was what he called a + 'buoyant sail,' which was in effect a man-lifting kite, and by means of + which a passenger was actually raised 100 yards from the ground, while the + inventor's son scaled a cliff 200 feet in height by means of one of these, + 'buoyant sails.' This constitutes the first definitely recorded experiment + in the use of man-lifting kites. A History of the Charvolant or + Kite-carriage, published in London in 1851, states that 'an experiment of + a bold and very novel character was made upon an extensive down, where a + large wagon with a considerable load was drawn along, whilst this huge + machine at the same time carried an observer aloft in the air, realising + almost the romance of flying.' + </p> + <p> + Experimenting, two years after the appearance of the 'kite-carriage,' on + the helicopter principle, W. H. Phillips constructed a model machine which + weighed two pounds; this was fitted with revolving fans, driven by the + combustion of charcoal, nitre, and gypsum, producing steam which, + discharging into the air, caused the fans to revolve. The inventor stated + that 'all being arranged, the steam was up in a few seconds, when the + whole apparatus spun around like any top, and mounted into the air faster + than a bird; to what height it ascended I had no means of ascertaining; + the distance travelled was across two fields, where, after a long search, + I found the machine minus the wings, which had been torn off in contact + with the ground.' This could hardly be described as successful flight, but + it was an advance in the construction of machines on the helicopter + principle, and it was the first steam-driven model of the type which + actually flew. The invention, however, was not followed up. + </p> + <p> + After Phillips, we come to the great figures of the middle nineteenth + century, W. S. Henson and John Stringfellow. Cayley had shown, in 1809, + how success might be attained by developing the idea of the plane surface + so driven as to take advantage of the resistance offered by the air, and + Henson, who as early as 1840 was experimenting with model gliders and + light steam engines, evolved and patented an idea for something very + nearly resembling the monoplane of the early twentieth century. His + patent, No. 9478, of the year 1842 explains the principle of the machine + as follows:— + </p> + <p> + In order that the description hereafter given be rendered clear, I will + first shortly explain the principle on which the machine is constructed. + If any light and flat or nearly flat article be projected or thrown + edgewise in a slightly inclined position, the same will rise on the air + till the force exerted is expended, when the article so thrown or + projected will descend; and it will readily be conceived that, if the + article so projected or thrown possessed in itself a continuous power or + force equal to that used in throwing or projecting it, the article would + continue to ascend so long as the forward part of the surface was upwards + in respect to the hinder part, and that such article, when the power was + stopped, or when the inclination was reversed, would descend by gravity + aided by the force of the power contained in the article, if the power be + continued, thus imitating the flight of a bird. + </p> + <p> + Now, the first part of my invention consists of an apparatus so + constructed as to offer a very extended surface or plane of a light yet + strong construction, which will have the same relation to the general + machine which the extended wings of a bird have to the body when a bird is + skimming in the air; but in place of the movement or power for onward + progress being obtained by movement of the extended surface or plane, as + is the case with the wings of birds, I apply suitable paddle-wheels or + other proper mechanical propellers worked by a steam or other sufficiently + light engine, and thus obtain the requisite power for onward movement to + the plane or extended surface; and in order to give control as to the + upward and downward direction of such a machine I apply a tail to the + extended surface which is capable of being inclined or raised, so that + when the power is acting to propel the machine, by inclining the tail + upwards, the resistance offered by the air will cause the machine to rise + on the air; and, on the contrary, when the inclination of the tail is + reversed, the machine will immediately be propelled downwards, and pass + through a plane more or less inclined to the horizon as the inclination of + the tail is greater or less; and in order to guide the machine as to the + lateral direction which it shall take, I apply a vertical rudder or second + tail, and, according as the same is inclined in one direction or the + other, so will be the direction of the machine.' + </p> + <p> + The machine in question was very large, and differed very little from the + modern monoplane; the materials were to be spars of bamboo and hollow + wood, with diagonal wire bracing. The surface of the planes was to amount + to 4,500 square feet, and the tail, triangular in form (here modern + practice diverges) was to be 1,500 square feet. The inventor estimated + that there would be a sustaining power of half a pound per square foot, + and the driving power was to be supplied by a steam engine of 25 to 30 + horse-power, driving two six-bladed propellers. Henson was largely + dependent on Stringfellow for many details of his design, more especially + with regard to the construction of the engine. + </p> + <p> + The publication of the patent attracted a great amount of public + attention, and the illustrations in contemporary journals, representing + the machine flying over the pyramids and the Channel, anticipated fact by + sixty years and more; the scientific world was divided, as it was up to + the actual accomplishment of flight, as to the value of the invention. + </p> + <p> + Strongfellow and Henson became associated after the conception of their + design, with an attorney named Colombine, and a Mr Marriott, and between + the four of them a project grew for putting the whole thing on a + commercial basis—Henson and Stringfellow were to supply the idea; + Marriott, knowing a member of Parliament, would be useful in getting a + company incorporated, and Colombine would look after the purely legal side + of the business. Thus an application was made by Mr Roebuck, Marriott's + M.P., for an act of incorporation for 'The Aerial Steam Transit Company,' + Roebuck moving to bring in the bill on the 24th of March, 1843. The + prospectus, calling for funds for the development of the invention, makes + interesting reading at this stage of aeronautical development; it was as + follows: + </p> +<pre xml:space="preserve"> + PROPOSAL. +</pre> + <p> + For subscriptions of sums of L100, in furtherance of an Extraordinary + Invention not at present safe to be developed by securing the necessary + Patents, for which three times the sum advanced, namely, L300, is + conditionally guaranteed for each subscription on February 1, 1844, in + case of the anticipations being realised, with the option of the + subscribers being shareholders for the large amount if so desired, but not + otherwise. + </p> + <p> + ————-An Invention has recently been discovered, + which if ultimately successful will be without parallel even in the age + which introduced to the world the wonderful effects of gas and of steam. + </p> + <p> + The discovery is of that peculiar nature, so simple in principle yet so + perfect in all the ingredients required for complete and permanent + success, that to promulgate it at present would wholly defeat its + development by the immense competition which would ensue, and the views of + the originator be entirely frustrated. + </p> + <p> + This work, the result of years of labour and study, presents a wonderful + instance of the adaptation of laws long since proved to the scientific + world combined with established principles so judiciously and carefully + arranged, as to produce a discovery perfect in all its parts and alike in + harmony with the laws of Nature and of science. + </p> + <p> + The Invention has been subjected to several tests and examinations and the + results are most satisfactory so much so that nothing but the completion + of the undertaking is required to determine its practical operation, which + being once established its utility is undoubted, as it would be a + necessary possession of every empire, and it were hardly too much to say, + of every individual of competent means in the civilised world. + </p> + <p> + Its qualities and capabilities are so vast that it were impossible and, + even if possible, unsafe to develop them further, but some idea may be + formed from the fact that as a preliminary measure patents in Great + Britain Ireland, Scotland, the Colonies, France, Belgium, and the United + States, and every other country where protection to the first discoveries + of an Invention is granted, will of necessity be immediately obtained, and + by the time these are perfected, which it is estimated will be in the + month of February, the Invention will be fit for Public Trial, but until + the Patents are sealed any further disclosure would be most dangerous to + the principle on which it is based. + </p> + <p> + Under these circumstances, it is proposed to raise an immediate sum of + L2,000 in furtherance of the Projector's views, and as some protection to + the parties who may embark in the matter, that this is not a visionary + plan for objects imperfectly considered, Mr Colombine, to whom the secret + has been confided, has allowed his name to be used on the occasion, and + who will if referred to corroborate this statement, and convince any + inquirer of the reasonable prospects of large pecuniary results following + the development of the Invention. + </p> + <p> + It is, therefore, intended to raise the sum of L2,000 in twenty sums of + L100 each (of which any subscriber may take one or more not exceeding five + in number to be held by any individual) the amount of which is to be paid + into the hands of Mr Colombine as General Manager of the concern to be by + him appropriated in procuring the several Patents and providing the + expenses incidental to the works in progress. For each of which sums of + L100 it is intended and agreed that twelve months after the 1st February + next, the several parties subscribing shall receive as an equivalent for + the risk to be run the sum of L300 for each of the sums of L100 now + subscribed, provided when the time arrives the Patents shall be found to + answer the purposes intended. + </p> + <p> + As full and complete success is alone looked to, no moderate or imperfect + benefit is to be anticipated, but the work, if it once passes the + necessary ordeal, to which inventions of every kind must be first subject, + will then be regarded by every one as the most astonishing discovery of + modern times; no half success can follow, and therefore the full nature of + the risk is immediately ascertained. + </p> + <p> + The intention is to work and prove the Patent by collective instead of + individual aid as less hazardous at first end more advantageous in the + result for the Inventor, as well as others, by having the interest of + several engaged in aiding one common object—the development of a + Great Plan. The failure is not feared, yet as perfect success might, by + possibility, not ensue, it is necessary to provide for that result, and + the parties concerned make it a condition that no return of the subscribed + money shall be required, if the Patents shall by any unforeseen + circumstances not be capable of being worked at all; against which, the + first application of the money subscribed, that of securing the Patents, + affords a reasonable security, as no one without solid grounds would think + of such an expenditure. + </p> + <p> + It is perfectly needless to state that no risk or responsibility of any + kind can arise beyond the payment of the sum to be subscribed under any + circumstances whatever. + </p> + <p> + As soon as the Patents shall be perfected and proved it is contemplated, + so far as may be found practicable, to further the great object in view a + Company shall be formed but respecting which it is unnecessary to state + further details, than that a preference will be given to all those persons + who now subscribe, and to whom shares shall be appropriated according to + the larger amount (being three times the sum to be paid by each person) + contemplated to be returned as soon as the success of the Invention shall + have been established, at their option, or the money paid, whereby the + Subscriber will have the means of either withdrawing with a large + pecuniary benefit, or by continuing his interest in the concern lay the + foundation for participating in the immense benefit which must follow the + success of the plan. + </p> + <p> + It is not pretended to conceal that the project is a speculation—all + parties believe that perfect success, and thence incalculable advantage of + every kind, will follow to every individual joining in this great + undertaking; but the Gentlemen engaged in it wish that no concealment of + the consequences, perfect success, or possible failure, should in the + slightest degree be inferred. They believe this will prove the germ of a + mighty work, and in that belief call for the operation of others with no + visionary object, but a legitimate one before them, to attain that point + where perfect success will be secured from their combined exertions. + </p> + <p> + All applications to be made to D. E. Colombine, Esquire, 8 Carlton + Chambers, Regent Street. + </p> + <p> + The applications did not materialise, as was only to be expected in view + of the vagueness of the proposals. Colombine did some advertising, and Mr + Roebuck expressed himself as unwilling to proceed further in the venture. + Henson experimented with models to a certain extent, while Stringfellow + looked for funds for the construction of a full-sized monoplane. In + November of 1843 he suggested that he and Henson should construct a large + model out of their own funds. On Henson's suggestion Colombine and + Marriott were bought out as regards the original patent, and Stringfellow + and Henson entered into an agreement and set to work. + </p> + <p> + Their work is briefly described in a little pamphlet by F. J. + Stringfellow, entitled A few Remarks on what has been done with + screw-propelled Aero-plane Machines from 1809 to 1892. The author writes + with regard to the work that his father and Henson undertook:— + </p> + <p> + 'They commenced the construction of a small model operated by a spring, + and laid down the larger model 20 ft. from tip to tip of planes, 3 1/2 ft. + wide, giving 70 ft. of sustaining surface, about 10 more in the tail. The + making of this model required great consideration; various supports for + the wings were tried, so as to combine lightness with firmness, strength + and rigidity. + </p> + <p> + 'The planes were staid from three sets of fish-shaped masts, and rigged + square and firm by flat steel rigging. The engine and boiler were put in + the car to drive two screw-propellers, right and left-handed, 3 ft. in + diameter, with four blades each, occupying three-quarters of the area of + the circumference, set at an angle of 60 degrees. A considerable time was + spent in perfecting the motive power. Compressed air was tried and + abandoned. Tappets, cams, and eccentrics were all tried, to work the slide + valve, to obtain the best results. The piston rod of engine passed through + both ends of the cylinder, and with long connecting rods worked direct on + the crank of the propellers. From memorandum of experiments still + preserved the following is a copy of one: June, 27th, 1845, water 50 ozs., + spirit 10 ozs., lamp lit 8.45, gauge moves 8.46, engine started 8.48 (100 + lb. pressure), engine stopped 8.57, worked 9 minutes, 2,288 revolutions, + average 254 per minute. No priming, 40 ozs. water consumed, propulsion + (thrust of propellers), 5 lbs. 4 1/2 ozs. at commencement, steady, 4 lbs. + 1/2 oz., 57 revolutions to 1 oz. water, steam cut off one-third from + beginning. + </p> + <p> + 'The diameter of cylinder of engine was 1 1/2 inch, length of stroke 3 + inches. + </p> + <p> + 'In the meantime an engine was also made for the smaller model, and a wing + action tried, but with poor results. The time was mostly devoted to the + larger model, and in 1847 a tent was erected on Bala Down, about two miles + from Chard, and the model taken up one night by the workmen. The + experiments were not so favourable as was expected. The machine could not + support itself for any distance, but, when launched off, gradually + descended, although the power and surface should have been ample; indeed, + according to latest calculations, the thrust should have carried more than + three times the weight, for there was a thrust of 5 lbs. from the + propellers, and a surface of over 70 square feet to sustain under 30 lbs., + but necessary speed was lacking.' + </p> + <p> + Stringfellow himself explained the failure as follows:— + </p> + <p> + 'There stood our aerial protegee in all her purity—too delicate, too + fragile, too beautiful for this rough world; at least those were my ideas + at the time, but little did I think how soon it was to be realised. I soon + found, before I had time to introduce the spark, a drooping in the wings, + a flagging in all the parts. In less than ten minutes the machine was + saturated with wet from a deposit of dew, so that anything like a trial + was impossible by night. I did not consider we could get the silk tight + and rigid enough. Indeed, the framework altogether was too weak. The + steam-engine was the best part. Our want of success was not for want of + power or sustaining surface, but for want of proper adaptation of the + means to the end of the various parts.' + </p> + <p> + Henson, who had spent a considerable amount of money in these experimental + constructions, consoled himself for failure by venturing into matrimony; + in 1849 he went to America, leaving Stringfellow to continue experimenting + alone. From 1846 to 1848 Stringfellow worked on what is really an + epoch-making item in the history of aeronautics—the first + engine-driven aeroplane which actually flew. The machine in question had a + 10 foot span, and was 2 ft. across in the widest part of the wing; the + length of tail was 3 ft. 6 ins., and the span of tail in the widest part + 22 ins., the total sustaining area being about 14 sq. ft. The motive power + consisted of an engine with a cylinder of three-quarter inch diameter and + a two-inch stroke; between this and the crank shaft was a bevelled gear + giving three revolutions of the propellers to every stroke of the engine; + the propellers, right and left screw, were four-bladed and 16 inches in + diameter. The total weight of the model with engine was 8 lbs. Its + successful flight is ascribed to the fact that Stringfellow curved the + wings, giving them rigid front edges and flexible trailing edges, as + suggested long before both by Da Vinci and Borelli, but never before put + into practice. + </p> + <p> + Mr F. J. Stringfellow, in the pamphlet quoted above, gives the best + account of the flight of this model: 'My father had constructed another + small model which was finished early in 1848, and having the loan of a + long room in a disused lace factory, early in June the small model was + moved there for experiments. The room was about 22 yards long and from 10 + to 12 ft. high.... The inclined wire for starting the machine occupied + less than half the length of the room and left space at the end for the + machine to clear the floor. In the first experiment the tail was set at + too high an angle, and the machine rose too rapidly on leaving the wire. + After going a few yards it slid back as if coming down an inclined plane, + at such an angle that the point of the tail struck the ground and was + broken. The tail was repaired and set at a smaller angle. The steam was + again got up, and the machine started down the wire, and, upon reaching + the point of self-detachment, it gradually rose until it reached the + farther end of the room, striking a hole in the canvas placed to stop it. + In experiments the machine flew well, when rising as much as one in seven. + The late Rev. J. Riste, Esq., lace manufacturer, Northcote Spicer, Esq., + J. Toms, Esq., and others witnessed experiments. Mr Marriatt, late of the + San Francisco News Letter brought down from London Mr Ellis, the then + lessee of Cremorne Gardens, Mr Partridge, and Lieutenant Gale, the + aeronaut, to witness experiments. Mr Ellis offered to construct a covered + way at Cremorne for experiments. Mr Stringfellow repaired to Cremorne, but + not much better accommodations than he had at home were provided, owing to + unfulfilled engagement as to room. Mr Stringfellow was preparing for + departure when a party of gentlemen unconnected with the Gardens begged to + see an experiment, and finding them able to appreciate his endeavours, he + got up steam and started the model down the wire. When it arrived at the + spot where it should leave the wire it appeared to meet with some + obstruction, and threatened to come to the ground, but it soon recovered + itself and darted off in as fair a flight as it was possible to make at a + distance of about 40 yards, where it was stopped by the canvas. + </p> + <p> + 'Having now demonstrated the practicability of making a steam-engine fly, + and finding nothing but a pecuniary loss and little honour, this + experimenter rested for a long time, satisfied with what he had effected. + The subject, however, had to him special charms, and he still contemplated + the renewal of his experiments.' + </p> + <p> + It appears that Stringfellow's interest did not revive sufficiently for + the continuance of the experiments until the founding of the Aeronautical + Society of Great Britain in 1866. Wenham's paper on Aerial Locomotion read + at the first meeting of the Society, which was held at the Society of Arts + under the Presidency of the Duke of Argyll, was the means of bringing + Stringfellow back into the field. It was Wenham's suggestion, in the first + place, that monoplane design should be abandoned for the superposition of + planes; acting on this suggestion Stringfellow constructed a model + triplane, and also designed a steam engine of slightly over one + horse-power, and a one horse-power copper boiler and fire box which, + although capable of sustaining a pressure of 500 lbs. to the square inch, + weighed only about 40 lbs. + </p> + <p> + Both the engine and the triplane model were exhibited at the first + Aeronautical Exhibition held at the Crystal Palace in 1868. The triplane + had a supporting surface of 28 sq. ft.; inclusive of engine, boiler, fuel, + and water its total weight was under 12 lbs. The engine worked two 21 in. + propellers at 600 revolutions per minute, and developed 100 lbs. steam + pressure in five minutes, yielding one-third horse-power. Since no free + flight was allowed in the Exhibition, owing to danger from fire, the + triplane was suspended from a wire in the nave of the building, and it was + noted that, when running along the wire, the model made a perceptible + lift. + </p> + <p> + A prize of L100 was awarded to the steam engine as the lightest steam + engine in proportion to its power. The engine and model together may be + reckoned as Stringfellow's best achievement. He used his L100 in + preparation for further experiments, but he was now an old man, and his + work was practically done. Both the triplane and the engine were + eventually bought for the Washington Museum; Stringfellow's earlier + models, together with those constructed by him in conjunction with Henson, + remain in this country in the Victoria and Albert Museum. + </p> + <p> + John Stringfellow died on December 13th, 1883. His place in the history of + aeronautics is at least equal to that of Cayley, and it may be said that + he laid the foundation of such work as was subsequently accomplished by + Maxim, Langley, and their fellows. It was the coming of the internal + combustion engine that rendered flight practicable, and had this prime + mover been available in John Stringfellow's day the Wright brothers' + achievement might have been antedated by half a century. + </p> + <p> + <a name="link2H_4_0007" id="link2H_4_0007"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + V. WENHAM, LE BRIS, AND SOME OTHERS + </h2> + <p> + There are few outstanding events in the development of aeronautics between + Stringfellow's final achievement and the work of such men as Lilienthal, + Pilcher, Montgomery, and their kind; in spite of this, the later middle + decades of the nineteenth century witnessed a considerable amount of spade + work both in England and in France, the two countries which led in the way + in aeronautical development until Lilienthal gave honour to Germany, and + Langley and Montgomery paved the way for the Wright Brothers in America. + </p> + <p> + Two abortive attempts characterised the sixties of last century in France. + As regards the first of these, it was carried out by three men, Nadar, + Ponton d'Amecourt, and De la Landelle, who conceived the idea of a + full-sized helicopter machine. D'Amecourt exhibited a steam model, + constructed in 1865, at the Aeronautical Society's Exhibition in 1868. The + engine was aluminium with cylinders of bronze, driving two screws placed + one above the other and rotating in Opposite directions, but the power was + not sufficient to lift the model. De la Landelle's principal achievement + consisted in the publication in 1863 of a book entitled Aviation which has + a certain historical value; he got out several designs for large machines + on the helicopter principle, but did little more until the three combined + in the attempt to raise funds for the construction of their full-sized + machine. Since the funds were not forthcoming, Nadar took to ballooning as + the means of raising money; apparently he found this substitute for real + flight sufficiently interesting to divert him from the study of the + helicopter principle, for the experiment went no further. + </p> + <p> + The other experimenter of this period, one Count d'Esterno, took out a + patent in 1864 for a soaring machine which allowed for alteration of the + angle of incidence of the wings in the manner that was subsequently + carried out by the Wright Brothers. It was not until 1883 that any attempt + was made to put this patent to practical use, and, as the inventor died + while it was under construction, it was never completed. D'Esterno was + also responsible for the production of a work entitled Du Vol des Oiseaux, + which is a very remarkable study of the flight of birds. + </p> + <p> + Mention has already been made of the founding of the Aeronautical Society + of Great Britain, which, since 1918 has been the Royal Aeronautical + Society. 1866 witnessed the first meeting of the Society under the + Presidency of the Duke of Argyll, when in June, at the Society of Arts, + Francis Herbert Wenham read his now classic paper Aerial Locomotion. + Certain quotations from this will show how clearly Wenham had thought out + the problems connected with flight. + </p> + <p> + 'The first subject for consideration is the proportion of surface to + weight, and their combined effect in descending perpendicularly through + the atmosphere. The datum is here based upon the consideration of safety, + for it may sometimes be needful for a living being to drop passively, + without muscular effort. One square foot of sustaining surface for every + pound of the total weight will be sufficient for security. + </p> + <p> + 'According to Smeaton's table of atmospheric resistances, to produce a + force of one pound on a square foot, the wind must move against the plane + (or which is the same thing, the plane against the wind), at the rate of + twenty-two feet per second, or 1,320 feet per minute, equal to fifteen + miles per hour. The resistance of the air will now balance the weight on + the descending surface, and, consequently, it cannot exceed that speed. + Now, twenty-two feet per second is the velocity acquired at the end of a + fall of eight feet—a height from which a well-knit man or animal may + leap down without much risk of injury. Therefore, if a man with parachute + weigh together 143 lbs., spreading the same number of square feet of + surface contained in a circle fourteen and a half feet in diameter, he + will descend at perhaps an unpleasant velocity, but with safety to life + and limb. + </p> + <p> + 'It is a remarkable fact how this proportion of wing-surface to weight + extends throughout a great variety of the flying portion of the animal + kingdom, even down to hornets, bees, and other insects. In some instances, + however, as in the gallinaceous tribe, including pheasants, this area is + somewhat exceeded, but they are known to be very poor fliers. Residing as + they do chiefly on the ground, their wings are only required for short + distances, or for raising them or easing their descent from their + roosting-places in forest trees, the shortness of their wings preventing + them from taking extended flights. The wing-surface of the common swallow + is rather more than in the ratio of two square feet per pound, but having + also great length of pinion, it is both swift and enduring in its flight. + When on a rapid course this bird is in the habit of furling its wings into + a narrow compass. The greater extent of surface is probably needful for + the continual variations of speed and instant stoppages for obtaining its + insect food. + </p> + <p> + 'On the other hand, there are some birds, particularly of the duck tribe, + whose wing-surface but little exceeds half a square foot, or seventy-two + inches per pound, yet they may be classed among the strongest and swiftest + of fliers. A weight of one pound, suspended from an area of this extent, + would acquire a velocity due to a fall of sixteen feet—a height + sufficient for the destruction or injury of most animals. But when the + plane is urged forward horizontally, in a manner analogous to the wings of + a bird during flight, the sustaining power is greatly influenced by the + form and arrangement of the surface. + </p> + <p> + 'In the case of perpendicular descent, as a parachute, the sustaining + effect will be much the same, whatever the figure of the outline of the + superficies may be, and a circle perhaps affords the best resistance of + any. Take, for example, a circle of twenty square feet (as possessed by + the pelican) loaded with as many pounds. This, as just stated, will limit + the rate of perpendicular descent to 1,320 feet per minute. But instead of + a circle sixty-one inches in diameter, if the area is bounded by a + parallelogram ten feet long by two feet broad, and whilst at perfect + freedom to descend perpendicularly, let a force be applied exactly in a + horizontal direction, so as to carry it edgeways, with the long side + foremost, at a forward speed of thirty miles per hour—just double + that of its passive descent: the rate of fall under these conditions will + be decreased most remarkably, probably to less than one-fifteenth part, or + eighty-eight feet per minute, or one mile per hour.' + </p> + <p> + And again: 'It has before been shown how utterly inadequate the mere + perpendicular impulse of a plane is found to be in supporting a weight, + when there is no horizontal motion at the time. There is no material + weight of air to be acted upon, and it yields to the slightest force, + however great the velocity of impulse may be. On the other hand, suppose + that a large bird, in full flight, can make forty miles per hour, or 3,520 + feet per minute, and performs one stroke per second. Now, during every + fractional portion of that stroke, the wing is acting upon and obtaining + an impulse from a fresh and undisturbed body of air; and if the vibration + of the wing is limited to an arc of two feet, this by no means represents + the small force of action that would be obtained when in a stationary + position, for the impulse is secured upon a stratum of fifty-eight feet in + length of air at each stroke. So that the conditions of weight of air for + obtaining support equally well apply to weight of air and its reaction in + producing forward impulse. + </p> + <p> + 'So necessary is the acquirement of this horizontal speed, even in + commencing flight, that most heavy birds, when possible, rise against the + wind, and even run at the top of their speed to make their wings + available, as in the example of the eagle, mentioned at the commencement + of this paper. It is stated that the Arabs, on horseback, can approach + near enough to spear these birds, when on the plain, before they are able + to rise; their habit is to perch on an eminence, where possible. + </p> + <p> + 'The tail of a bird is not necessary for flight. A pigeon can fly + perfectly with this appendage cut short off; it probably performs an + important function in steering, for it is to be remarked, that most birds + that have either to pursue or evade pursuit are amply provided with this + organ. + </p> + <p> + 'The foregoing reasoning is based upon facts, which tend to show that the + flight of the largest and heaviest of all birds is really performed with + but a small amount of force, and that man is endowed with sufficient + muscular power to enable him also to take individual and extended flights, + and that success is probably only involved in a question of suitable + mechanical adaptations. But if the wings are to be modelled in imitation + of natural examples, but very little consideration will serve to + demonstrate its utter impracticability when applied in these forms.' + </p> + <p> + Thus Wenham, one of the best theorists of his age. The Society with which + this paper connects his name has done work, between that time and the + present, of which the importance cannot be overestimated, and has been of + the greatest value in the development of aeronautics, both in theory and + experiment. The objects of the Society are to give a stronger impulse to + the scientific study of aerial navigation, to promote the intercourse of + those interested in the subject at home and abroad, and to give advice and + instruction to those who study the principles upon which aeronautical + science is based. From the date of its foundation the Society has given + special study to dynamic flight, putting this before ballooning. Its + library, its bureau of advice and information, and its meetings, all + assist in forwarding the study of aeronautics, and its twenty-three early + Annual Reports are of considerable value, containing as they do a large + amount of useful information on aeronautical subjects, and forming + practically the basis of aeronautical science. + </p> + <p> + Ante to Wenham, Stringfellow and the French experimenters already noted, + by some years, was Le Bris, a French sea captain, who appears to have + required only a thorough scientific training to have rendered him of equal + moment in the history of gliding flight with Lilienthal himself. Le Bris, + it appears, watched the albatross and deduced, from the manner in which it + supported itself in the air, that plane surfaces could be constructed and + arranged to support a man in like manner. Octave Chanute, himself a + leading exponent of gliding, gives the best description of Le Bris's + experiments in a work, Progress in Flying Machines, which, although + published as recently as I 1894, is already rare. Chanute draws from a + still rarer book, namely, De la Landelle's work published in 1884. Le Bris + himself, quoted by De la Landelle as speaking of his first visioning of + human flight, describes how he killed an albatross, and then—'I took + the wing of the albatross and exposed it to the breeze; and lo! in spite + of me it drew forward into the wind; notwithstanding my resistance it + tended to rise. Thus I had discovered the secret of the bird! I + comprehended the whole mystery of flight.' + </p> + <p> + This apparently took place while at sea; later on Le Bris, returning to + France, designed and constructed an artificial albatross of sufficient + size to bear his own weight. The fact that he followed the bird outline as + closely as he did attests his lack of scientific training for his task, + while at the same time the success of the experiment was proof of his + genius. The body of his artificial bird, boat-shaped, was 13 1/2 ft. in + length, with a breadth of 4 ft. at the widest part. The material was cloth + stretched over a wooden framework; in front was a small mast rigged after + the manner of a ship's masts to which were attached poles and cords with + which Le Bris intended to work the wings. Each wing was 23 ft. in length, + giving a total supporting surface of nearly 220 sq. ft.; the weight of the + whole apparatus was only 92 pounds. For steering, both vertical and + horizontal, a hinged tail was provided, and the leading edge of each wing + was made flexible. In construction throughout, and especially in that of + the wings, Le Bris adhered as closely as possible to the original + albatross. + </p> + <p> + He designed an ingenious kind of mechanism which he termed 'Rotules,' + which by means of two levers gave a rotary motion to the front edge of the + wings, and also permitted of their adjustment to various angles. The + inventor's idea was to stand upright in the body of the contrivance, + working the levers and cords with his hands, and with his feet on a pedal + by means of which the steering tail was to be worked. He anticipated that, + given a strong wind, he could rise into the air after the manner of an + albatross, without any need for flapping his wings, and the account of his + first experiment forms one of the most interesting incidents in the + history of flight. It is related in full in Chanute's work, from which the + present account is summarised. + </p> + <p> + Le Bris made his first experiment on a main road near Douarnenez, at + Trefeuntec. From his observation of the albatross Le Bris concluded that + it was necessary to get some initial velocity in order to make the machine + rise; consequently on a Sunday morning, with a breeze of about 12 miles an + hour blowing down the road, he had his albatross placed on a cart and set + off, with a peasant driver, against the wind. At the outset the machine + was fastened to the cart by a rope running through the rails on which the + machine rested, and secured by a slip knot on Le Bris's own wrist, so that + only a jerk on his part was necessary to loosen the rope and set the + machine free. On each side walked an assistant holding the wings, and when + a turn of the road brought the machine full into the wind these men were + instructed to let go, while the driver increased the pace from a walk to a + trot. Le Bris, by pressure on the levers of the machine, raised the front + edges of his wings slightly; they took the wind almost instantly to such + an extent that the horse, relieved of a great part of the weight he had + been drawing, turned his trot into a gallop. Le Bris gave the jerk of the + rope that should have unfastened the slip knot, but a concealed nail on + the cart caught the rope, so that it failed to run. The lift of the + machine was such, however, that it relieved the horse of very nearly the + weight of the cart and driver, as well as that of Le Bris and his machine, + and in the end the rails of the cart gave way. Le Bris rose in the air, + the machine maintaining perfect balance and rising to a height of nearly + 300 ft., the total length of the glide being upwards of an eighth of a + mile. But at the last moment the rope which had originally fastened the + machine to the cart got wound round the driver's body, so that this + unfortunate dangled in the air under Le Bris and probably assisted in + maintaining the balance of the artificial albatross. Le Bris, + congratulating himself on his success, was prepared to enjoy just as long + a time in the air as the pressure of the wind would permit, but the howls + of the unfortunate driver at the end of the rope beneath him dispelled his + dreams; by working his levers he altered the angle of the front wing edges + so skilfully as to make a very successful landing indeed for the driver, + who, entirely uninjured, disentangled himself from the rope as soon as he + touched the ground, and ran off to retrieve his horse and cart. + </p> + <p> + Apparently his release made a difference in the centre of gravity, for Le + Bris could not manipulate his levers for further ascent; by skilful + manipulation he retarded the descent sufficiently to escape injury to + himself; the machine descended at an angle, so that one wing, striking the + ground in front of the other, received a certain amount of damage. + </p> + <p> + It may have been on account of the reluctance of this same or another + driver that Le Bris chose a different method of launching himself in + making a second experiment with his albatross. He chose the edge of a + quarry which had been excavated in a depression of the ground; here he + assembled his apparatus at the bottom of the quarry, and by means of a + rope was hoisted to a height of nearly 100 ft. from the quarry bottom, + this rope being attached to a mast which he had erected upon the edge of + the depression in which the quarry was situated. Thus hoisted, the + albatross was swung to face a strong breeze that blew inland, and Le Bris + manipulated his levers to give the front edges of his wings a downward + angle, so that only the top surfaces should take the wing pressure. Having + got his balance, he obtained a lifting angle of incidence on the wings by + means of his levers, and released the hook that secured the machine, + gliding off over the quarry. On the glide he met with the inevitable + upward current of air that the quarry and the depression in which it was + situated caused; this current upset the balance of the machine and flung + it to the bottom of the quarry, breaking it to fragments. Le Bris, + apparently as intrepid as ingenious, gripped the mast from which his + levers were worked, and, springing upward as the machine touched earth, + escaped with no more damage than a broken leg. But for the rebound of the + levers he would have escaped even this. + </p> + <p> + The interest of these experiments is enhanced by the fact that Le Bris was + a seafaring man who conducted them from love of the science which had + fired his imagination, and in so doing exhausted his own small means. It + was in 1855 that he made these initial attempts, and twelve years passed + before his persistence was rewarded by a public subscription made at Brest + for the purpose of enabling him to continue his experiments. He built a + second albatross, and on the advice of his friends ballasted it for flight + instead of travelling in it himself. It was not so successful as the + first, probably owing to the lack of human control while in flight; on one + of the trials a height of 150 ft. was attained, the glider being secured + by a thin rope and held so as to face into the wind. A glide of nearly an + eighth of a mile was made with the rope hanging slack, and, at the end of + this distance, a rise in the ground modified the force of the wind, + whereupon the machine settled down without damage. A further trial in a + gusty wind resulted in the complete destruction of this second machine; Le + Bris had no more funds, no further subscriptions were likely to + materialise, and so the experiments of this first exponent of the art of + gliding (save for Besnier and his kind) came to an end. They constituted a + notable achievement, and undoubtedly Le Bris deserves a better place than + has been accorded him in the ranks of the early experimenters. + </p> + <p> + Contemporary with him was Charles Spencer, the first man to practice + gliding in England. His apparatus consisted of a pair of wings with a + total area of 30 sq. ft., to which a tail and body were attached. The + weight of this apparatus was some 24 lbs., and, launching himself on it + from a small eminence, as was done later by Lilienthal in his experiments, + the inventor made flights of over 120 feet. The glider in question was + exhibited at the Aeronautical Exhibition of 1868. + </p> + <p> + <a name="link2H_4_0008" id="link2H_4_0008"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + VI. THE AGE OF THE GIANTS + </h2> + <p> + Until the Wright Brothers definitely solved the problem of flight and + virtually gave the aeroplane its present place in aeronautics, there were + three definite schools of experiment. The first of these was that which + sought to imitate nature by means of the ornithopter or flapping-wing + machines directly imitative of bird flight; the second school was that + which believed in the helicopter or lifting screw; the third and + eventually successful school is that which followed up the principle + enunciated by Cayley, that of opposing a plane surface to the resistance + of the air by supplying suitable motive power to drive it at the requisite + angle for support. + </p> + <p> + Engineering problems generally go to prove that too close an imitation of + nature in her forms of recipro-cating motion is not advantageous; it is + impossible to copy the minutiae of a bird's wing effectively, and the bird + in flight depends on the tiniest details of its feathers just as much as + on the general principle on which the whole wing is constructed. Bird + flight, however, has attracted many experimenters, including even + Lilienthal; among others may be mentioned F. W. Brearey, who invented what + he called the 'Pectoral cord,' which stored energy on each upstroke of the + artificial wing; E. P. Frost; Major R. Moore, and especially Hureau de + Villeneuve, a most enthusiastic student of this form of flight, who began + his experiments about 1865, and altogether designed and made nearly 300 + artificial birds, one of his later constructions was a machine in bird + form with a wing span of about 50 ft.; the motive power for this was + supplied by steam from a boiler which, being stationary on the ground, was + connected by a length of hose to the machine. De Villeneuve, turning on + steam for his first trial, obtained sufficient power to make the wings + beat very forcibly; with the inventor on the machine the latter rose + several feet into the air, whereupon de Villeneuve grew nervous and turned + off the steam supply. The machine fell to the earth, breaking one of its + wings, and it does not appear that de Villeneuve troubled to reconstruct + it. This experiment remains as the greatest success yet achieved by any + machine constructed on the ornithopter principle. + </p> + <p> + It may be that, as forecasted by the prophet Wells, the flapping-wing + machine will yet come to its own and compete with the aeroplane in + efficiency. Against this, however, are the practical advantages of the + rotary mechanism of the aeroplane propeller as compared with the movement + of a bird's wing, which, according to Marey, moves in a figure of eight. + The force derived from a propeller is of necessity continual, while it is + equally obvious that that derived from a flapping movement is + intermittent, and, in the recovery of a wing after completion of one + stroke for the next, there is necessarily a certain cessation, if not + loss, of power. + </p> + <p> + The matter of experiment along any lines in connection with aviation is + primarily one of hard cash. Throughout the whole history of flight up to + the outbreak of the European war development has been handicapped on the + score of finance, and, since the arrival of the aeroplane, both + ornithopter and helicopter schools have been handicapped by this + consideration. Thus serious study of the efficiency of wings in imitation + of those of the living bird has not been carried to a point that might win + success for this method of propulsion. Even Wilbur Wright studied this + subject and propounded certain theories, while a later and possibly more + scientific student, F. W. Lanchester, has also contributed empirical + conclusions. Another and earlier student was Lawrence Hargrave, who made a + wing-propelled model which achieved successful flight, and in 1885 was + exhibited before the Royal Society of New South Wales. Hargrave called the + principle on which his propeller worked that of a 'Trochoided plane'; it + was, in effect, similar to the feathering of an oar. + </p> + <p> + Hargrave, to diverge for a brief while from the machine to the man, was + one who, although he achieved nothing worthy of special remark, + contributed a great deal of painstaking work to the science of flight. He + made a series of experiments with man-lifting kites in addition to making + a study of flapping-wing flight. It cannot be said that he set forth any + new principle; his work was mainly imitative, but at the same time by + developing ideas originated in great measure by others he helped toward + the solution of the problem. + </p> + <p> + Attempts at flight on the helicopter principle consist in the work of De + la Landelle and others already mentioned. The possibility of flight by + this method is modified by a very definite disadvantage of which lovers of + the helicopter seem to take little account. It is always claimed for a + machine of this type that it possesses great advantages both in rising and + in landing, since, if it were effective, it would obviously be able to + rise from and alight on any ground capable of containing its own bulk; a + further advantage claimed is that the helicopter would be able to remain + stationary in the air, maintaining itself in any position by the vertical + lift of its propeller. + </p> + <p> + These potential assets do not take into consideration the fact that + efficiency is required not only in rising, landing, and remaining + stationary in the air, but also in actual flight. It must be evident that + if a certain amount of the motive force is used in maintaining the machine + off the ground, that amount of force is missing from the total of + horizontal driving power. Again, it is often assumed by advocates of this + form of flight that the rapidity of climb of the helicopter would be far + greater than that of the driven plane; this view overlooks the fact that + the maintenance of aerodynamic support would claim the greater part of the + engine-power; the rate of ascent would be governed by the amount of power + that could be developed surplus to that required for maintenance. + </p> + <p> + This is best explained by actual figures: assuming that a propeller 15 ft. + in diameter is used, almost 50 horse-power would be required to get an + upward lift of 1,000 pounds; this amount of horse-power would be + continually absorbed in maintaining the machine in the air at any given + level; for actual lift from one level to another at a speed of eleven feet + per second a further 20 horse-power would be required, which means that 70 + horse-power must be constantly provided for; this absorption of power in + the mere maintenance of aero-dynamic support is a permanent drawback. + </p> + <p> + The attraction of the helicopter lies, probably, in the ease with which + flight is demonstrated by means of models constructed on this principle, + but one truism with regard to the principles of flight is that the + problems change remarkably, and often unexpectedly, with the size of the + machine constructed for experiment. Berriman, in a brief but very + interesting manual entitled Principles of Flight, assumed that 'there is a + significant dimension of which the effective area is an expression of the + second power, while the weight became an expression of the third power. + Then once again we have the two-thirds power law militating against the + successful construction of large helicopters, on the ground that the + essential weight increases disproportionately fast to the effective area. + From a consideration of the structural features of propellers it is + evident that this particular relationship does not apply in practice, but + it seems reasonable that some such governing factor should exist as an + explanation of the apparent failure of all full-sized machines that have + been constructed. Among models there is nothing more strikingly successful + than the toy helicopter, in which the essential weight is so small + compared with the effective area.' + </p> + <p> + De la Landelle's work, already mentioned, was carried on a few years later + by another Frenchman, Castel, who constructed a machine with eight + propellers arranged in two fours and driven by a compressed air motor or + engine. The model with which Castel experimented had a total weight of + only 49 lbs.; it rose in the air and smashed itself by driving against a + wall, and the inventor does not seem to have proceeded further. + Contemporary with Castel was Professor Forlanini, whose design was for a + machine very similar to de la Landelle's, with two superposed screws. This + machine ranks as the second on the helicopter principle to achieve flight; + it remained in the air for no less than the third of a minute in one of + its trials. + </p> + <p> + Later experimenters in this direction were Kress, a German; Professor + Wellner, an Austrian; and W. R. Kimball, an American. Kress, like most + Germans, set to the development of an idea which others had originated; he + followed de la Landelle and Forlanini by fitting two superposed propellers + revolving in opposite directions, and with this machine he achieved good + results as regards horse-power to weight; Kimball, it appears, did not get + beyond the rubber-driven model stage, and any success he may have achieved + was modified by the theory enunciated by Berriman and quoted above. + </p> + <p> + Comparing these two schools of thought, the helicopter and bird-flight + schools, it appears that the latter has the greater chance of eventual + success—that is, if either should ever come into competition with + the aeroplane as effective means of flight. So far, the aeroplane holds + the field, but the whole science of flight is so new and so full of + unexpected developments that this is no reason for assuming that other + means may not give equal effect, when money and brains are diverted from + the driven plane to a closer imitation of natural flight. + </p> + <p> + Reverting from non-success to success, from consideration of the two + methods mentioned above to the direction in which practical flight has + been achieved, it is to be noted that between the time of Le Bris, + Stringfellow, and their contemporaries, and the nineties of last century, + there was much plodding work carried out with little visible result, more + especially so far as English students were concerned. Among the incidents + of those years is one of the most pathetic tragedies in the whole history + of aviation, that of Alphonse Penaud, who, in his thirty years of life, + condensed the experience of his predecessors and combined it with his own + genius to state in a published patent what the aeroplane of to-day should + be. Consider the following abstract of Penaud's design as published in his + patent of 1876, and comparison of this with the aeroplane that now exists + will show very few divergences except for those forced on the inventor by + the fact that the internal combustion engine had not then developed. The + double surfaced planes were to be built with wooden ribs and arranged with + a slight dihedral angle; there was to be a large aspect ratio and the + wings were cambered as in Stringfellow's later models. Provision was made + for warping the wings while in flight, and the trailing edges were so + designed as to be capable of upward twist while the machine was in the + air. The planes were to be placed above the car, and provision was even + made for a glass wind-screen to give protection to the pilot during + flight. Steering was to be accomplished by means of lateral and vertical + planes forming a tail; these controlled by a single lever corresponding to + the 'joy stick' of the present day plane. + </p> + <p> + Penaud conceived this machine as driven by two propellers; alternatively + these could be driven by petrol or steam-fed motor, and the centre of + gravity of the machine while in flight was in the front fifth of the + wings. Penaud estimated from 20 to 30 horse-power sufficient to drive this + machine, weighing with pilot and passenger 2,600 lbs., through the air at + a speed of 60 miles an hour, with the wings set at an angle of incidence + of two degrees. So complete was the design that it even included + instruments, consisting of an aneroid, pressure indicator, an anemometer, + a compass, and a level. There, with few alterations, is the aeroplane as + we know it—and Penaud was twenty-seven when his patent was + published. + </p> + <p> + For three years longer he worked, experimenting with models, contributing + essays and other valuable data to French papers on the subject of + aeronautics. His gains were ill health, poverty, and neglect, and at the + age of thirty a pistol shot put an end to what had promised to be one of + the most brilliant careers in all the history of flight. + </p> + <p> + Two years before the publication of Penaud's patent Thomas Moy + experimented at the Crystal Palace with a twin-propelled aeroplane, steam + driven, which seems to have failed mainly because the internal combustion + engine had not yet come to give sufficient power for weight. Moy anchored + his machine to a pole running on a prepared circular track; his engine + weighed 80 lbs. and, developing only three horse-power, gave him a speed + of 12 miles an hour. He himself estimated that the machine would not rise + until he could get a speed of 35 miles an hour, and his estimate was + correct. Two six-bladed propellers were placed side by side between the + two main planes of the machine, which was supported on a triangular + wheeled undercarriage and steered by fairly conventional tail planes. Moy + realised that he could not get sufficient power to achieve flight, but he + went on experimenting in various directions, and left much data concerning + his experiments which has not yet been deemed worthy of publication, but + which still contains a mass of information that is of practical utility, + embodying as it does a vast amount of painstaking work. + </p> + <p> + Penaud and Moy were followed by Goupil, a Frenchman, who, in place of + attempting to fit a motor to an aeroplane, experimented by making the wind + his motor. He anchored his machine to the ground, allowing it two feet of + lift, and merely waited for a wind to come along and lift it. The machine + was stream lined, and the wings, curving as in the early German patterns + of war aeroplanes, gave a total lifting surface of about 290 sq. ft. + Anchored to the ground and facing a wind of 19 feet per second, Goupil's + machine lifted its own weight and that of two men as well to the limit of + its anchorage. Although this took place as late as 1883 the inventor went + no further in practical work. He published a book, however, entitled La + Locomotion Aerienne, which is still of great importance, more especially + on the subject of inherent stability. + </p> + <p> + In 1884 came the first patents of Horatio Phillips, whose work lay mainly + in the direction of investigation into the curvature of plane surfaces, + with a view to obtaining the greatest amount of support. Phillips was one + of the first to treat the problem of curvature of planes as a matter for + scientific experiment, and, great as has been the development of the + driven plane in the 36 years that have passed since he began, there is + still room for investigation into the subject which he studied so + persistently and with such valuable result. + </p> + <p> + At this point it may be noted that, with the solitary exception of Le + Bris, practically every student of flight had so far set about + constructing the means of launching humanity into the air without any + attempt at ascertaining the nature and peculiarities of the sustaining + medium. The attitude of experimenters in general might be compared to that + of a man who from boyhood had grown up away from open water, and, at the + first sight of an expanse of water, set to work to construct a boat with a + vague idea that, since wood would float, only sufficient power was + required to make him an efficient navigator. Accident, perhaps, in the + shape of lack of means of procuring driving power, drove Le Bris to the + form of experiment which he actually carried out; it remained for the + later years of the nineteenth century to produce men who were content to + ascertain the nature of the support the air would afford before attempting + to drive themselves through it. + </p> + <p> + Of the age in which these men lived and worked, giving their all in many + cases to the science they loved, even to life itself, it may be said with + truth that 'there were giants on the earth in those days,' as far as + aeronautics is in question. It was an age of giants who lived and dared + and died, venturing into uncharted space, knowing nothing of its dangers, + giving, as a man gives to his mistress, without stint and for the joy of + the giving. The science of to-day, compared with the glimmerings that were + in that age of the giants, is a fixed and certain thing; the problems of + to-day are minor problems, for the great major problem vanished in + solution when the Wright Brothers made their first ascent. In that age of + the giants was evolved the flying man, the new type in human species which + found full expression and came to full development in the days of the war, + achieving feats of daring and endurance which leave the commonplace + landsman staggered at thought of that of which his fellows prove + themselves capable. He is a new type, this flying man, a being of + self-forgetfulness; of such was Lilienthal, of such was Pilcher; of such + in later days were Farman, Bleriot, Hamel, Rolls, and their fellows; great + names that will live for as long as man flies, adventurers equally with + those of the spacious days of Elizabeth. To each of these came the call, + and he worked and dared and passed, having, perhaps, advanced one little + step in the long march that has led toward the perfecting of flight. + </p> + <p> + It is not yet twenty years since man first flew, but into that twenty + years have been compressed a century or so of progress, while, in the two + decades that preceded it, was compressed still more. We have only to + recall and recount the work of four men: Lilienthal, Langley, Pilcher, and + Clement Ader to see the immense stride that was made between the time when + Penaud pulled a trigger for the last time and the Wright Brothers first + left the earth. Into those two decades was compressed the investigation + that meant knowledge of the qualities of the air, together with the + development of the one prime mover that rendered flight a possibility—the + internal combustion engine. The coming and progress of this latter is a + thing apart, to be detailed separately; for the present we are concerned + with the evolution of the driven plane, and with it the evolution of that + daring being, the flying man. The two are inseparable, for the men gave + themselves to their art; the story of Lilienthal's life and death is the + story of his work; the story of Pilcher's work is that of his life and + death. + </p> + <p> + Considering the flying man as he appeared in the war period, there entered + into his composition a new element—patriotism—which brought + about a modification of the type, or, perhaps, made it appear that certain + men belonged to the type who in reality were commonplace mortals, + animated, under normal conditions, by normal motives, but driven by the + stress of the time to take rank with the last expression of human energy, + the flying type. However that may be, what may be termed the mathematising + of aeronautics has rendered the type itself evanescent; your pilot of + to-day knows his craft, once he is trained, much in the manner that a + driver of a motor-lorry knows his vehicle; design has been systematised, + capabilities have been tabulated; camber, dihedral angle, aspect ratio, + engine power, and plane surface, are business items of drawing office and + machine shop; there is room for enterprise, for genius, and for skill; + once and again there is room for daring, as in the first Atlantic flight. + Yet that again was a thing of mathematical calculation and petrol storage, + allied to a certain stark courage which may be found even in landsmen. For + the ventures into the unknown, the limit of daring, the work for work's + sake, with the almost certainty that the final reward was death, we must + look back to the age of the giants, the age when flying was not a + business, but romance. + </p> + <p> + <a name="link2H_4_0009" id="link2H_4_0009"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + VII. LILIENTHAL AND PILCHER + </h2> + <p> + There was never a more enthusiastic and consistent student of the problems + of flight than Otto Lilienthal, who was born in 1848 at Anklam, Pomerania, + and even from his early school-days dreamed and planned the conquest of + the air. His practical experiments began when, at the age of thirteen, he + and his brother Gustav made wings consisting of wooden framework covered + with linen, which Otto attached to his arms, and then ran downhill + flapping them. In consequence of possible derision on the part of other + boys, Otto confined these experiments for the most part to moonlit nights, + and gained from them some idea of the resistance offered by flat surfaces + to the air. It was in 1867 that the two brothers began really practical + work, experimenting with wings which, from their design, indicate some + knowledge of Besnier and the history of his gliding experiments; these + wings the brothers fastened to their backs, moving them with their legs + after the fashion of one attempting to swim. Before they had achieved any + real success in gliding the Franco-German war came as an interruption; + both brothers served in this campaign, resuming their experiments in 1871 + at the conclusion of hostilities. + </p> + <p> + The experiments made by the brothers previous to the war had convinced + Otto that previous experimenters in gliding flight had failed through + reliance on empirical conclusions or else through incomplete observation + on their own part, mostly of bird flight. From 1871 onward Otto Lilenthal + (Gustav's interest in the problem was not maintained as was his brother's) + made what is probably the most detailed and accurate series of + observations that has ever been made with regard to the properties of + curved wing surfaces. So far as could be done, Lilienthal tabulated the + amount of air resistance offered to a bird's wing, ascertaining that the + curve is necessary to flight, as offering far more resistance than a flat + surface. Cayley, and others, had already stated this, but to Lilienthal + belongs the honour of being first to put the statement to effective proof—he + made over 2,000 gliding flights between 1891 and the regrettable end of + his experiments; his practical conclusions are still regarded as part of + the accepted theory of students of flight. In 1889 he published a work on + the subject of gliding flight which stands as data for investigators, and, + on the conclusions embodied in this work, he began to build his gliders + and practice what he had preached, turning from experiment with models to + wings that he could use. + </p> + <p> + It was in the summer of 1891 that he built his first glider of rods of + peeled willow, over which was stretched strong cotton fabric; with this, + which had a supporting surface of about 100 square feet, Otto Lilienthal + launched himself in the air from a spring board, making glides which, at + first of only a few feet, gradually lengthened. As his experience of the + supporting qualities of the air progressed he gradually altered his + designs until, when Pilcher visited him in the spring of 1895, he + experimented with a glider, roughly made of peeled willow rods and cotton + fabric, having an area of 150 square feet and weighing half a + hundredweight. By this time Lilienthal had moved from his springboard to a + conical artificial hill which he had had thrown up on level ground at + Grosse Lichterfelde, near Berlin. This hill was made with earth taken from + the excavations incurred in constructing a canal, and had a cave inside in + which Lilienthal stored his machines. Pilcher, in his paper on 'Gliding,' + [*] gives an excellent short summary of Lilienthal's experiments, from + which the following extracts are taken:— + </p> + <p> + [*] Aeronautical Classes, No. 5. Royal Aeronautical Society's + publications. + </p> + <p> + 'At first Lilienthal used to experiment by jumping off a springboard with + a good run. Then he took to practicing on some hills close to Berlin. In + the summer of 1892 he built a flat-roofed hut on the summit of a hill, + from the top of which he used to jump, trying, of course, to soar as far + as possible before landing.... One of the great dangers with a soaring + machine is losing forward speed, inclining the machine too much down in + front, and coming down head first. Lilienthal was the first to introduce + the system of handling a machine in the air merely by moving his weight + about in the machine; he always rested only on his elbows or on his elbows + and shoulders.... + </p> + <p> + 'In 1892 a canal was being cut, close to where Lilienthal lived, in the + suburbs of Berlin, and with the surplus earth Lilienthal had a special + hill thrown up to fly from. The country round is as flat as the sea, and + there is not a house or tree near it to make the wind unsteady, so this + was an ideal practicing ground; for practicing on natural hills is + generally rendered very difficult by shifty and gusty winds.... This hill + is 50 feet high, and conical. Inside the hill there is a cave for the + machines to be kept in.... When Lilienthal made a good flight he used to + land 300 feet from the centre of the hill, having come down at an angle of + 1 in 6; but his best flights have been at an angle of about 1 in 10. + </p> + <p> + 'If it is calm, one must run a few steps down the hill, holding the + machine as far back on oneself as possible, when the air will gradually + support one, and one slides off the hill into the air. If there is any + wind, one should face it at starting; to try to start with a side wind is + most unpleasant. It is possible after a great deal of practice to turn in + the air, and fairly quickly. This is accomplished by throwing one's weight + to one side, and thus lowering the machine on that side towards which one + wants to turn. Birds do the same thing—crows and gulls show it very + clearly. Last year Lilienthal chiefly experimented with double-surfaced + machines. These were very much like the old machines with awnings spread + above them. + </p> + <p> + 'The object of making these double-surfaced machines was to get more + surface without increasing the length and width of the machine. This, of + course, it does, but I personally object to any machine in which the wing + surface is high above the weight. I consider that it makes the machine + very difficult to handle in bad weather, as a puff of wind striking the + surface, high above one, has a great tendency to heel the machine over. + </p> + <p> + 'Herr Lilienthal kindly allowed me to sail down his hill in one of these + double-surfaced machines last June. With the great facility afforded by + his conical hill the machine was handy enough; but I am afraid I should + not be able to manage one at all in the squally districts I have had to + practice in over here. + </p> + <p> + 'Herr Lilienthal came to grief through deserting his old method of + balancing. In order to control his tipping movements more rapidly he + attached a line from his horizontal rudder to his head, so that when he + moved his head forward it would lift the rudder and tip the machine up in + front, and vice versa. He was practicing this on some natural hills + outside Berlin, and he apparently got muddled with the two motions, and, + in trying to regain speed after he had, through a lull in the wind, come + to rest in the air, let the machine get too far down in front, came down + head first and was killed.' + </p> + <p> + Then in another passage Pilcher enunciates what is the true value of such + experiments as Lilienthal—and, subsequently, he himself—made: + 'The object of experimenting with soaring machines,' he says, 'is to + enable one to have practice in starting and alighting and controlling a + machine in the air. They cannot possibly float horizontally in the air for + any length of time, but to keep going must necessarily lose in elevation. + They are excellent schooling machines, and that is all they are meant to + be, until power, in the shape of an engine working a screw propeller, or + an engine working wings to drive the machine forward, is added; then a + person who is used to soaring down a hill with a simple soaring machine + will be able to fly with comparative safety. One can best compare them to + bicycles having no cranks, but on which one could learn to balance by + coming down an incline.' + </p> + <p> + It was in 1895 that Lilienthal passed from experiment with the monoplane + type of glider to the construction of a biplane glider which, according to + his own account, gave better results than his previous machines. 'Six or + seven metres velocity of wind,' he says, 'sufficed to enable the sailing + surface of 18 square metres to carry me almost horizontally against the + wind from the top of my hill without any starting jump. If the wind is + stronger I allow myself to be simply lifted from the point of the hill and + to sail slowly towards the wind. The direction of the flight has, with + strong wind, a strong upwards tendency. I often reach positions in the air + which are much higher than my starting point. At the climax of such a line + of flight I sometimes come to a standstill for some time, so that I am + enabled while floating to speak with the gentlemen who wish to photograph + me, regarding the best position for the photographing.' + </p> + <p> + Lilienthal's work did not end with simple gliding, though he did not live + to achieve machine-driven flight. Having, as he considered, gained + sufficient experience with gliders, he constructed a power-driven machine + which weighed altogether about 90 lbs., and this was thoroughly tested. + The extremities of its wings were made to flap, and the driving power was + obtained from a cylinder of compressed carbonic acid gas, released through + a hand-operated valve which, Lilienthal anticipated, would keep the + machine in the air for four minutes. There were certain minor accidents to + the mechanism, which delayed the trial flights, and on the day that + Lilienthal had determined to make his trial he made a long gliding flight + with a view to testing a new form of rudder that—as Pilcher relates—was + worked by movements of his head. His death came about through the causes + that Pilcher states; he fell from a height of 50 feet, breaking his spine, + and the next day he died. + </p> + <p> + It may be said that Lilienthal accomplished as much as any one of the + great pioneers of flying. As brilliant in his conceptions as da Vinci had + been in his, and as conscientious a worker as Borelli, he laid the + foundations on which Pilcher, Chanute, and Professor Montgomery were able + to build to such good purpose. His book on bird flight, published in 1889, + with the authorship credited both to Otto and his brother Gustav, is + regarded as epoch-making; his gliding experiments are no less entitled to + this description. + </p> + <p> + In England Lilienthal's work was carried on by Percy Sinclair Pilcher, + who, born in 1866, completed six years' service in the British Navy by the + time that he was nineteen, and then went through a course of engineering, + subsequently joining Maxim in his experimental work. It was not until 1895 + that he began to build the first of the series of gliders with which he + earned his plane among the pioneers of flight. Probably the best account + of Pilcher's work is that given in the Aeronautical Classics issued by the + Royal Aeronautical Society, from which the following account of Pilcher's + work is mainly abstracted.[*] + </p> + <p> + [*] Aeronautical Classes, No. 5. Royal Aeronautical Society publications. + </p> + <p> + The 'Bat,' as Pilcher named his first glider, was a monoplane which he + completed before he paid his visit to Lilienthal in 1895. Concerning this + Pilcher stated that he purposely finished his own machine before going to + see Lilienthal, so as to get the greatest advantage from any original + ideas he might have; he was not able to make any trials with this machine, + however, until after witnessing Lilienthal's experiments and making + several glides in the biplane glider which Lilienthal constructed. + </p> + <p> + The wings of the 'Bat' formed a pronounced dihedral angle; the tips being + raised 4 feet above the body. The spars forming the entering edges of the + wings crossed each other in the centre and were lashed to opposite sides + of the triangle that served as a mast for the stay-wires that guyed the + wings. The four ribs of each wing, enclosed in pockets in the fabric, + radiated fanwise from the centre, and were each stayed by three steel + piano-wires to the top of the triangular mast, and similarly to its base. + These ribs were bolted down to the triangle at their roots, and could be + easily folded back on to the body when the glider was not in use. A small + fixed vertical surface was carried in the rear. The framework and ribs + were made entirely of Riga pine; the surface fabric was nainsook. The area + of the machine was 150 square feet; its weight 45 lbs.; so that in flight, + with Pilcher's weight of 145 lbs. added, it carried one and a half pounds + to the square foot. + </p> + <p> + Pilcher's first glides, which he carried out on a grass hill on the banks + of the Clyde near Cardross, gave little result, owing to the exaggerated + dihedral angle of the wings, and the absence of a horizontal tail. The + 'Bat 'was consequently reconstructed with a horizontal tail plane added to + the vertical one, and with the wings lowered so that the tips were only + six inches above the level of the body. The machine now gave far better + results; on the first glide into a head wind Pilcher rose to a height of + twelve feet and remained in the the air for a third of a minute; in the + second attempt a rope was used to tow the glider, which rose to twenty + feet and did not come to earth again until nearly a minute had passed. + With experience Pilcher was able to lengthen his glide and improve his + balance, but the dropped wing tips made landing difficult, and there were + many breakages. + </p> + <p> + In consequence of this Pilcher built a second glider which he named the + 'Beetle,' because, as he said, it looked like one. In this the square-cut + wings formed almost a continuous plane, rigidly fixed to the central body, + which consisted of a shaped girder. These wings were built up of five + transverse bamboo spars, with two shaped ribs running from fore to aft of + each wing, and were stayed overhead to a couple of masts. The tail, + consisting of two discs placed crosswise (the horizontal one alone being + movable), was carried high up in the rear. With the exception of the + wing-spars, the whole framework was built of white pine. The wings in this + machine were actually on a higher level than the operator's head; the + centre of gravity was, consequently, very low, a fact which, according to + Pilcher's own account, made the glider very difficult to handle. Moreover, + the weight of the 'Beetle,' 80 lbs., was considerable; the body had been + very solidly built to enable it to carry the engine which Pilcher was then + contemplating; so that the glider carried some 225 lbs. with its area of + 170 square feet—too great a mass for a single man to handle with + comfort. + </p> + <p> + It was in the spring of 1896 that Pilcher built his third glider, the + 'Gull,' with 300 square feet of area and a weight of 55 lbs. The size of + this machine rendered it unsuitable for experiment in any but very calm + weather, and it incurred such damage when experiments were made in a + breeze that Pilcher found it necessary to build a fourth, which he named + the 'Hawk.' This machine was very soundly built, being constructed of + bamboo, with the exception of the two main transverse beams. The wings + were attached to two vertical masts, 7 feet high, and 8 feet apart, joined + at their summits and their centres by two wooden beams. Each wing had nine + bamboo ribs, radiating from its mast, which was situated at a distance of + 2 feet 6 inches from the forward edge of the wing. Each rib was rigidly + stayed at the top of the mast by three tie-wires, and by a similar number + to the bottom of the mast, by which means the curve of each wing was + maintained uniformly. The tail was formed of a triangular horizontal + surface to which was affixed a triangular vertical surface, and was + carried from the body on a high bamboo mast, which was also stayed from + the masts by means of steel wires, but only on its upper surface, and it + was the snapping of one of these guy wires which caused the collapse of + the tail support and brought about the fatal end of Pilcher's experiments. + In flight, Pilcher's head, shoulders, and the greater part of his chest + projected above the wings. He took up his position by passing his head and + shoulders through the top aperture formed between the two wings, and + resting his forearms on the longitudinal body members. A very simple form + of undercarriage, which took the weight off the glider on the ground, was + fitted, consisting of two bamboo rods with wheels suspended on steel + springs. + </p> + <p> + Balance and steering were effected, apart from the high degree of inherent + stability afforded by the tail, as in the case of Lilienthal's glider, by + altering the position of the body. With this machine Pilcher made some + twelve glides at Eynsford in Kent in the summer of 1896, and as he + progressed he increased the length of his glides, and also handled the + machine more easily, both in the air and in landing. He was occupied with + plans for fitting an engine and propeller to the 'Hawk,' but, in these + early days of the internal combustion engine, was unable to get one light + enough for his purpose. There were rumours of an engine weighing 15 lbs. + which gave 1 horse-power, and was reported to be in existence in America, + but it could not be traced. + </p> + <p> + In the spring of 1897 Pilcher took up his gliding experiments again, + obtaining what was probably the best of his glides on June 19th, when he + alighted after a perfectly balanced glide of over 250 yards in length, + having crossed a valley at a considerable height. From his various + experiments he concluded that once the machine was launched in the air an + engine of, at most, 3 horse-power would suffice for the maintenance of + horizontal flight, but he had to allow for the additional weight of the + engine and propeller, and taking into account the comparative inefficiency + of the propeller, he planned for an engine of 4 horse-power. Engine and + propeller together were estimated at under 44 lbs. weight, the engine was + to be fitted in front of the operator, and by means of an overhead shaft + was to operate the propeller situated in rear of the wings. 1898 went by + while this engine was under construction. Then in 1899 Pilcher became + interested in Lawrence Hargrave's soaring kites, with which he carried out + experiments during the summer of 1899. It is believed that he intended to + incorporate a number of these kites in a new machine, a triplane, of which + the fragments remaining are hardly sufficient to reconstitute the complete + glider. This new machine was never given a trial. For on September 30th, + 1899, at Stamford Hall, Market Harborough, Pilcher agreed to give a + demonstration of gliding flight, but owing to the unfavourable weather he + decided to postpone the trial of the new machine and to experiment with + the 'Hawk,' which was intended to rise from a level field, towed by a line + passing over a tackle drawn by two horses. At the first trial the machine + rose easily, but the tow-line snapped when it was well clear of the + ground, and the glider descended, weighed down through being sodden with + rain. Pilcher resolved on a second trial, in which the glider again rose + easily to about thirty feet, when one of the guy wires of the tail broke, + and the tail collapsed; the machine fell to the ground, turning over, and + Pilcher was unconscious when he was freed from the wreckage. + </p> + <p> + Hopes were entertained of his recovery, but he died on Monday, October + 2nd, 1899, aged only thirty-four. His work in the cause of flying lasted + only four years, but in that time his actual accomplishments were + sufficient to place his name beside that of Lilienthal, with whom he ranks + as one of the greatest exponents of gliding flight. + </p> + <p> + <a name="link2H_4_0010" id="link2H_4_0010"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + VIII. AMERICAN GLIDING EXPERIMENTS + </h2> + <p> + While Pilcher was carrying on Lilienthal's work in England, the great + German had also a follower in America; one Octave Chanute, who, in one of + the statements which he has left on the subject of his experiments + acknowledges forty years' interest in the problem of flight, did more to + develop the glider in America than—with the possible exception of + Montgomery—any other man. Chanute had all the practicality of an + American; he began his work, so far as actual gliding was concerned, with + a full-sized glider of the Lilienthal type, just before Lilienthal was + killed. In a rather rare monograph, entitled Experiments in Flying, + Chanute states that he found the Lilienthal glider hazardous and decided + to test the value of an idea of his own; in this he followed the same + general method, but reversed the principle upon which Lilienthal had + depended for maintaining his equilibrium in the air. Lilienthal had + shifted the weight of his body, under immovable wings, as fast and as far + as the sustaining pressure varied under his surfaces; this shifting was + mainly done by moving the feet, as the actions required were small except + when alighting. Chanute's idea was to have the operator remain seated in + the machine in the air, and to intervene only to steer or to alight; + moving mechanism was provided to adjust the wings automatically in order + to restore balance when necessary. + </p> + <p> + Chanute realised that experiments with models were of little use; in order + to be fully instructive, these experiments should be made with a + full-sized machine which carried its operator, for models seldom fly twice + alike in the open air, and no relation can be gained from them of the + divergent air currents which they have experienced. Chanute's idea was + that any flying machine which might be constructed must be able to operate + in a wind; hence the necessity for an operator to report upon what + occurred in flight, and to acquire practical experience of the work of the + human factor in imitation of bird flight. From this point of view he + conducted his own experiments; it must be noted that he was over sixty + years of age when he began, and, being no longer sufficiently young and + active to perform any but short and insignificant glides, the courage of + the man becomes all the more noteworthy; he set to work to evolve the + state required by the problem of stability, and without any expectation of + advancing to the construction of a flying machine which might be of + commercial value. His main idea was the testing of devices to secure + equilibrium; for this purpose he employed assistants to carry out the + practical work, where he himself was unable to supply the necessary + physical energy. + </p> + <p> + Together with his assistants he found a suitable place for experiments + among the sandhills on the shore of Lake Michigan, about thirty miles + eastward from Chicago. Here a hill about ninety-five feet high was + selected as a point from which Chanute's gliders could set off; in + practice, it was found that the best observation was to be obtained from + short glides at low speed, and, consequently, a hill which was only + sixty-one feet above the shore of the lake was employed for the + experimental work done by the party. + </p> + <p> + In the years 1896 and 1897, with parties of from four to six persons, five + full-sized gliders were tried out, and from these two distinct types were + evolved: of these one was a machine consisting of five tiers of wings and + a steering tail, and the other was of the biplane type; Chanute believed + these to be safer than any other machine previously evolved, solving, as + he states in his monograph, the problem of inherent equilibrium as fully + as this could be done. Unfortunately, very few photographs were taken of + the work in the first year, but one view of a multiple wing-glider + survives, showing the machine in flight. In 1897 a series of photographs + was taken exhibiting the consecutive phases of a single flight; this + series of photographs represents the experience gained in a total of about + one thousand glides, but the point of view was varied so as to exhibit the + consecutive phases of one single flight. + </p> + <p> + The experience gained is best told in Chanute's own words. 'The first + thing,' he says, 'which we discovered practically was that the wind + flowing up a hill-side is not a steadily-flowing current like that of a + river. It comes as a rolling mass, full of tumultuous whirls and eddies, + like those issuing from a chimney; and they strike the apparatus with + constantly varying force and direction, sometimes withdrawing support when + most needed. It has long been known, through instrumental observations, + that the wind is constantly changing in force and direction; but it needed + the experience of an operator afloat on a gliding machine to realise that + this all proceeded from cyclonic action; so that more was learned in this + respect in a week than had previously been acquired by several years of + experiments with models. There was a pair of eagles, living in the top of + a dead tree about two miles from our tent, that came almost daily to show + us how such wind effects are overcome and utilised. The birds swept in + circles overhead on pulseless wings, and rose high up in the air. + Occasionally there was a side-rocking motion, as of a ship rolling at sea, + and then the birds rocked back to an even keel; but although we thought + the action was clearly automatic, and were willing to learn, our teachers + were too far off to show us just how it was done, and we had to experiment + for ourselves.' + </p> + <p> + Chanute provided his multiple glider with a seat, but, since each glide + only occupied between eight and twelve seconds, there was little + possibility of the operator seating himself. With the multiple glider a + pair of horizontal bars provided rest for the arms, and beyond these was a + pair of vertical bars which the operator grasped with his hands; beyond + this, the operator was in no way attached to the machine. He took, at the + most, four running steps into the wind, which launched him in the air, and + thereupon he sailed into the wind on a generally descending course. In the + matter of descent Chanute observed the sparrow and decided to imitate it. + 'When the latter,' he says, 'approaches the street, he throws his body + back, tilts his outspread wings nearly square to the course, and on the + cushion of air thus encountered he stops his speed and drops lightly to + the ground. So do all birds. We tried it with misgivings, but found it + perfectly effective. The soft sand was a great advantage, and even when + the experts were racing there was not a single sprained ankle.' + </p> + <p> + With the multiple winged glider some two to three hundred glides were made + without any accident either to the man or to the machine, and the action + was found so effective, the principle so sound, that full plans were + published for the benefit of any experimenters who might wish to improve + on this apparatus. The American Aeronautical Annual for 1897 contains + these plans; Chanute confessed that some movement on the part of the + operator was still required to control the machine, but it was only a + seventh or a sixth part of the movement required for control of the + Lilienthal type. + </p> + <p> + Chanute waxed enthusiastic over the possibilities of gliding, concerning + which he remarks that 'There is no more delightful sensation than that of + gliding through the air. All the faculties are on the alert, and the + motion is astonishingly smooth and elastic. The machine responds instantly + to the slightest movement of the operator; the air rushes by one's ears; + the trees and bushes flit away underneath, and the landing comes all too + quickly. Skating, sliding, and bicycling are not to be compared for a + moment to aerial conveyance, in which, perhaps, zest is added by the spice + of danger. For it must be distinctly understood that there is constant + danger in such preliminary experiments. When this hazard has been + eliminated by further evolution, gliding will become a most popular + sport.' + </p> + <p> + Later experiments proved that the biplane type of glider gave better + results than the rather cumbrous model consisting of five tiers of planes. + Longer and more numerous glides, to the number of seven to eight hundred, + were obtained, the rate of descent being about one in six. The longest + distance traversed was about 120 yards, but Chanute had dreams of starting + from a hill about 200 feet high, which would have given him gliding + flights of 1,200 feet. He remarked that 'In consequence of the speed + gained by running, the initial stage of the flight is nearly horizontal, + and it is thrilling to see the operator pass from thirty to forty feet + overhead, steering his machine, undulating his course, and struggling with + the wind-gusts which whistle through the guy wires. The automatic + mechanism restores the angle of advance when compromised by variations of + the breeze; but when these come from one side and tilt the apparatus, the + weight has to be shifted to right the machine... these gusts sometimes + raise the machine from ten to twenty feet vertically, and sometimes they + strike the apparatus from above, causing it to descend suddenly. When + sailing near the ground, these vicissitudes can be counteracted by + movements of the body from three to four inches; but this has to be done + instantly, for neither wings nor gravity will wait on meditation. At a + height of three hundred or four hundred feet the regulating mechanism + would probably take care of these wind-gusts, as it does, in fact, for + their minor variations. The speed of the machine is generally about + seventeen miles an hour over the ground, and from twenty-two to thirty + miles an hour relative to the air. Constant effort was directed to keep + down the velocity, which was at times fifty-two miles an hour. This is the + purpose of the starting and gliding against the wind, which thus furnishes + an initial velocity without there being undue speed at the landing. The + highest wind we dared to experiment in blew at thirty-one miles an hour; + when the wind was stronger, we waited and watched the birds.' + </p> + <p> + Chanute details an amusing little incident which occurred in the course of + experiment with the biplane glider. He says that 'We had taken one of the + machines to the top of the hill, and loaded its lower wings with sand to + hold it while we e went to lunch. A gull came strolling inland, and + flapped full-winged to inspect. He swept several circles above the + machine, stretched his neck, gave a squawk and went off. Presently he + returned with eleven other gulls, and they seemed to hold a conclave about + one hundred feet above the big new white bird which they had discovered on + the sand. They circled round after round, and once in a while there was a + series of loud peeps, like those of a rusty gate, as if in conference, + with sudden flutterings, as if a terrifying suggestion had been made. The + bolder birds occasionally swooped downwards to inspect the monster more + closely; they twisted their heads around to bring first one eye and then + the other to bear, and then they rose again. After some seven or eight + minutes of this performance, they evidently concluded either that the + stranger was too formidable to tackle, if alive, or that he was not good + to eat, if dead, and they flew off to resume fishing, for the weak point + about a bird is his stomach.' + </p> + <p> + The gliders were found so stable, more especially the biplane form, that + in the end Chanute permitted amateurs to make trials under guidance, and + throughout the whole series of experiments not a single accident occurred. + Chanute came to the conclusion that any young, quick, and handy man could + master a gliding machine almost as soon as he could get the hang of a + bicycle, although the penalty for any mistake would be much more severe. + </p> + <p> + At the conclusion of his experiments he decided that neither the multiple + plane nor the biplane type of glider was sufficiently perfected for the + application of motive power. In spite of the amount of automatic stability + that he had obtained he considered that there was yet more to be done, and + he therefore advised that every possible method of securing stability and + safety should be tested, first with models, and then with full-sized + machines; designers, he said, should make a point of practice in order to + make sure of the action, to proportion and adjust the parts of their + machine, and to eliminate hidden defects. Experimental flight, he + suggested, should be tried over water, in order to break any accidental + fall; when a series of experiments had proved the stability of a glider, + it would then be time to apply motive power. He admitted that such a + process would be both costly and slow, but, he said, that 'it greatly + diminished the chance of those accidents which bring a whole line of + investigation into contempt.' He saw the flying machine as what it has, in + fact, been; a child of evolution, carried on step by step by one + investigator after another, through the stages of doubt and perplexity + which lie behind the realm of possibility, beyond which is the present day + stage of actual performance and promise of ultimate success and triumph + over the earlier, more cumbrous, and slower forms of the transport that we + know. + </p> + <p> + Chanute's monograph, from which the foregoing notes have been comprised, + was written soon after the conclusion of his series of experiments. He + does not appear to have gone in for further practical work, but to have + studied the subject from a theoretical view-point and with great attention + to the work done by others. In a paper contributed in 1900 to the American + Independent, he remarks that 'Flying machines promise better results as to + speed, but yet will be of limited commercial application. They may carry + mails and reach other inaccessible places, but they cannot compete with + railroads as carriers of passengers or freight. They will not fill the + heavens with commerce, abolish custom houses, or revolutionise the world, + for they will be expensive for the loads which they can carry, and subject + to too many weather contingencies. Success is, however, probable. Each + experimenter has added something to previous knowledge which his + successors can avail of. It now seems likely that two forms of flying + machines, a sporting type and an exploration type, will be gradually + evolved within one or two generations, but the evolution will be costly + and slow, and must be carried on by well-equipped and thoroughly informed + scientific men; for the casual inventor, who relies upon one or two happy + inspirations, will have no chance of success whatever.' + </p> + <p> + Follows Professor John J. Montgomery, who, in the true American spirit, + describes his own experiments so well that nobody can possibly do it + better. His account of his work was given first of all in the American + Journal, Aeronautics, in January, 1909, and thence transcribed in the + English paper of the same name in May, 1910, and that account is here + copied word for word. It may, however, be noted first that as far back as + 1860, when Montgomery was only a boy, he was attracted to the study of + aeronautical problems, and in 1883 he built his first machine, which was + of the flapping-wing ornithopter type, and which showed its designer, with + only one experiment, that he must design some other form of machine if he + wished to attain to a successful flight. Chanute details how, in 1884 and + 1885 Montgomery built three gliders, demonstrating the value of curved + surfaces. With the first of these gliders Montgomery copied the wing of a + seagull; with the second he proved that a flat surface was virtually + useless, and with the third he pivoted his wings as in the Antoinette type + of power-propelled aeroplane, proving to his own satisfaction that success + lay in this direction. His own account of the gliding flights carried out + under his direction is here set forth, being the best description of his + work that can be obtained:— + </p> + <p> + 'When I commenced practical demonstration in my work with aeroplanes I had + before me three points; first, equilibrium; second, complete control; and + third, long continued or soaring flight. In starting I constructed and + tested three sets of models, each in advance of the other in regard to the + continuance of their soaring powers, but all equally perfect as to + equilibrium and control. These models were tested by dropping them from a + cable stretched between two mountain tops, with various loads, adjustments + and positions. And it made no difference whether the models were dropped + upside down or any other conceivable position, they always found their + equilibrium immediately and glided safely to earth. + </p> + <p> + 'Then I constructed a large machine patterned after the first model, and + with the assistance of three cowboy friends personally made a number of + flights in the steep mountains near San Juan (a hundred miles distant). In + making these flights I simply took the aeroplane and made a running jump. + These tests were discontinued after I put my foot into a squirrel hole in + landing and hurt my leg. + </p> + <p> + 'The following year I commenced the work on a larger scale, by engaging + aeronauts to ride my aeroplane dropped from balloons. During this work I + used five hot-air balloons and one gas balloon, five or six aeroplanes, + three riders—Maloney, Wilkie, and Defolco—and had sixteen + applicants on my list, and had a training station to prepare any when I + needed them. + </p> + <p> + 'Exhibitions were given in Santa Cruz, San Jose, Santa Clara, Oaklands, + and Sacramento. The flights that were made, instead of being haphazard + affairs, were in the order of safety and development. In the first flight + of an aeronaut the aeroplane was so arranged that the rider had little + liberty of action, consequently he could make only a limited flight. In + some of the first flights, the aeroplane did little more than settle in + the air. But as the rider gained experience in each successive flight I + changed the adjustments, giving him more liberty of action, so he could + obtain longer flights and more varied movements in the flights. But in + none of the flights did I have the adjustments so that the riders had full + liberty, as I did not consider that they had the requisite knowledge and + experience necessary for their safety; and hence, none of my aeroplanes + were launched so arranged that the rider could make adjustments necessary + for a full flight. + </p> + <p> + 'This line of action caused a good deal of trouble with aeronauts or + riders, who had unbounded confidence and wanted to make long flights after + the first few trials; but I found it necessary, as they seemed slow in + comprehending the important elements and were willing to take risks. To + give them the full knowledge in these matters I was formulating plans for + a large starting station on the Mount Hamilton Range from which I could + launch an aeroplane capable of carrying two, one of my aeronauts and + myself, so I could teach him by demonstration. But the disasters + consequent on the great earthquake completely stopped all my work on these + lines. The flights that were given were only the first of the series with + aeroplanes patterned after the first model. There were no aeroplanes + constructed according to the two other models, as I had not given the full + demonstration of the workings of the first, though some remarkable and + startling work was done. On one occasion Maloney, in trying to make a very + short turn in rapid flight, pressed very hard on the stirrup which gives a + screw-shape to the wings, and made a side somersault. The course of the + machine was very much like one turn of a corkscrew. After this movement + the machine continued on its regular course. And afterwards Wilkie, not to + be outdone by Maloney, told his friends he would do the same, and in a + subsequent flight made two side somersaults, one in one direction and the + other in an opposite, then made a deep dive and a long glide, and, when + about three hundred feet in the air, brought the aeroplane to a sudden + stop and settled to the earth. After these antics, I decreased the extent + of the possible change in the form of wing-surface, so as to allow only + straight sailing or only long curves in turning. + </p> + <p> + 'During my work I had a few carping critics that I silenced by this + standing offer: If they would deposit a thousand dollars I would cover it + on this proposition. I would fasten a 150 pound sack of sand in the + rider's seat, make the necessary adjustments, and send up an aeroplane + upside down with a balloon, the aeroplane to be liberated by a time fuse. + If the aeroplane did not immediately right itself, make a flight, and come + safely to the ground, the money was theirs. + </p> + <p> + 'Now a word in regard to the fatal accident. The circumstances are these: + The ascension was given to entertain a military company in which were many + of Maloney's friends, and he had told them he would give the most + sensational flight they ever heard of. As the balloon was rising with the + aeroplane, a guy rope dropping switched around the right wing and broke + the tower that braced the two rear wings and which also gave control over + the tail. We shouted Maloney that the machine was broken, but he probably + did not hear us, as he was at the same time saying, "Hurrah for + Montgomery's airship," and as the break was behind him, he may not have + detected it. Now did he know of the breakage or not, and if he knew of it + did he take a risk so as not to disappoint his friends? At all events, + when the machine started on its flight the rear wings commenced to flap + (thus indicating they were loose), the machine turned on its back, and + settled a little faster than a parachute. When we reached Maloney he was + unconscious and lived only thirty minutes. The only mark of any kind on + him was a scratch from a wire on the side of his neck. The six attending + physicians were puzzled at the cause of his death. This is remarkable for + a vertical descent of over 2,000 feet.' + </p> + <p> + The flights were brought to an end by the San Francisco earthquake in + April, 1906, which, Montgomery states, 'Wrought such a disaster that I had + to turn my attention to other subjects and let the aeroplane rest for a + time.' Montgomery resumed experiments in 1911 in California, and in + October of that year an accident brought his work to an end. The report in + the American Aeronautics says that 'a little whirlwind caught the machine + and dashed it head on to the ground; Professor Montgomery landed on his + head and right hip. He did not believe himself seriously hurt, and talked + with his year-old bride in the tent. He complained of pains in his back, + and continued to grow worse until he died.' + </p> + <p> + <a name="link2H_4_0011" id="link2H_4_0011"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + IX. NOT PROVEN + </h2> + <p> + The early history of flying, like that of most sciences, is replete with + tragedies; in addition to these it contains one mystery concerning Clement + Ader, who was well known among European pioneers in the development of the + telephone, and first turned his attention to the problems of mechanical + flight in 1872. At the outset he favoured the ornithopter principle, + constructing a machine in the form of a bird with a wing-spread of + twenty-six feet; this, according to Ader's conception, was to fly through + the efforts of the operator. The result of such an attempt was past + question and naturally the machine never left the ground. + </p> + <p> + A pause of nineteen years ensued, and then in 1886 Ader turned his mind to + the development of the aeroplane, constructing a machine of bat-like form + with a wingspread of about forty-six feet, a weight of eleven hundred + pounds, and a steam-power plant of between twenty and thirty horse-power + driving a four-bladed tractor screw. On October 9th, 1890, the first + trials of this machine were made, and it was alleged to have flown a + distance of one hundred and sixty-four feet. Whatever truth there may be + in the allegation, the machine was wrecked through deficient equilibrium + at the end of the trial. Ader repeated the construction, and on October + 14th, 1897, tried out his third machine at the military establishment at + Satory in the presence of the French military authorities, on a circular + track specially prepared for the experiment. Ader and his friends alleged + that a flight of nearly a thousand feet was made; again the machine was + wrecked at the end of the trial, and there Ader's practical work may be + said to have ended, since no more funds were forthcoming for the subsidy + of experiments. + </p> + <p> + There is the bald narrative, but it is worthy of some amplification. If + Ader actually did what he claimed, then the position which the Wright + Brothers hold as first to navigate the air in a power-driven plane is + nullified. Although at this time of writing it is not a quarter of a + century since Ader's experiment in the presence of witnesses competent to + judge on his accomplishment, there is no proof either way, and whether he + was or was not the first man to fly remains a mystery in the story of the + conquest of the air. + </p> + <p> + The full story of Ader's work reveals a persistence and determination to + solve the problem that faced him which was equal to that of Lilienthal. He + began by penetrating into the interior of Algeria after having disguised + himself as an Arab, and there he spent some months in studying flight as + practiced by the vultures of the district. Returning to France in 1886 he + began to construct the 'Eole,' modelling it, not on the vulture, but in + the shape of a bat. Like the Lilienthal and Pilcher gliders this machine + was fitted with wings which could be folded; the first flight made, as + already noted, on October 9th, 1890, took place in the grounds of the + chateau d'Amainvilliers, near Bretz; two fellow-enthusiasts named Espinosa + and Vallier stated that a flight was actually made; no statement in the + history of aeronautics has been subject of so much question, and the claim + remains unproved. + </p> + <p> + It was in September of 1891 that Ader, by permission of the Minister of + War, moved the 'Eole' to the military establishment at Satory for the + purpose of further trial. By this time, whether he had flown or not, his + nineteen years of work in connection with the problems attendant on + mechanical flight had attracted so much attention that henceforth his work + was subject to the approval of the military authorities, for already it + was recognised that an efficient flying machine would confer an + inestimable advantage on the power that possessed it in the event of war. + At Satory the 'Eole' was alleged to have made a flight of 109 yards, or, + according to another account, 164 feet, as stated above, in the trial in + which the machine wrecked itself through colliding with some carts which + had been placed near the track—the root cause of this accident, + however, was given as deficient equilibrium. + </p> + <p> + Whatever the sceptics may say, there is reason for belief in the + accomplishment of actual flight by Ader with his first machine in the fact + that, after the inevitable official delay of some months, the French War + Ministry granted funds for further experiment. Ader named his second + machine, which he began to build in May, 1892, the 'Avion,' and—an + honour which he well deserve—that name remains in French aeronautics + as descriptive of the power-driven aeroplane up to this day. + </p> + <p> + This second machine, however, was not a success, and it was not until 1897 + that the second 'Avion,' which was the third power-driven aeroplane of + Ader's construction, was ready for trial. This was fitted with two steam + motors of twenty horse-power each, driving two four-bladed propellers; the + wings warped automatically: that is to say, if it were necessary to raise + the trailing edge of one wing on the turn, the trailing edge of the + opposite wing was also lowered by the same movement; an under-carriage was + also fitted, the machine running on three small wheels, and levers + controlled by the feet of the aviator actuated the movement of the tail + planes. + </p> + <p> + On October the 12th, 1897, the first trials of this 'Avion' were made in + the presence of General Mensier, who admitted that the machine made + several hops above the ground, but did not consider the performance as one + of actual flight. The result was so encouraging, in spite of the partial + failure, that, two days later, General Mensier, accompanied by General + Grillon, a certain Lieutenant Binet, and two civilians named respectively + Sarrau and Leaute, attended for the purpose of giving the machine an + official trial, over which the great controversy regarding Ader's success + or otherwise may be said to have arisen. + </p> + <p> + We will take first Ader's own statement as set out in a very competent + account of his work published in Paris in 1910. Here are Ader's own words: + 'After some turns of the propellers, and after travelling a few metres, we + started off at a lively pace; the pressure-gauge registered about seven + atmospheres; almost immediately the vibrations of the rear wheel ceased; a + little later we only experienced those of the front wheels at intervals. + 'Unhappily, the wind became suddenly strong, and we had some difficulty in + keeping the "Avion" on the white line. We increased the pressure to + between eight and nine atmospheres, and immediately the speed increased + considerably, and the vibrations of the wheels were no longer sensible; we + were at that moment at the point marked G in the sketch; the "Avion" then + found itself freely supported by its wings; under the impulse of the wind + it continually tended to go outside the (prepared) area to the right, in + spite of the action of the rudder. On reaching the point V it found itself + in a very critical position; the wind blew strongly and across the + direction of the white line which it ought to follow; the machine then, + although still going forward, drifted quickly out of the area; we + immediately put over the rudder to the left as far as it would go; at the + same time increasing the pressure still more, in order to try to regain + the course. The "Avion" obeyed, recovered a little, and remained for some + seconds headed towards its intended course, but it could not struggle + against the wind; instead of going back, on the contrary it drifted + farther and farther away. And ill-luck had it that the drift took the + direction towards part of the School of Musketry, which was guarded by + posts and barriers. Frightened at the prospect of breaking ourselves + against these obstacles, surprised at seeing the earth getting farther + away from under the "Avion," and very much impressed by seeing it rushing + sideways at a sickening speed, instinctively we stopped everything. What + passed through our thoughts at this moment which threatened a tragic turn + would be difficult to set down. All at once came a great shock, + splintering, a heavy concussion: we had landed.' + </p> + <p> + Thus speaks the inventor; the cold official mind gives out a different + account, crediting the 'Avion' with merely a few hops, and to-day, among + those who consider the problem at all, there is a little group which + persists in asserting that to Ader belongs the credit of the first + power-driven flight, while a larger group is equally persistent in stating + that, save for a few ineffectual hops, all three wheels of the machine + never left the ground. It is past question that the 'Avion' was capable of + power-driven flight; whether it achieved it or no remains an unsettled + problem. + </p> + <p> + Ader's work is negative proof of the value of such experiments as + Lilienthal, Pilcher, Chanute, and Montgomery conducted; these four set to + work to master the eccentricities of the air before attempting to use it + as a supporting medium for continuous flight under power; Ader attacked + the problem from the other end; like many other experimenters he regarded + the air as a stable fluid capable of giving such support to his machine as + still water might give to a fish, and he reckoned that he had only to + produce the machine in order to achieve flight. The wrecked 'Avion' and + the refusal of the French War Ministry to grant any more funds for further + experiment are sufficient evidence of the need for working along the lines + taken by the pioneers of gliding rather than on those which Ader himself + adopted. + </p> + <p> + Let it not be thought that in this comment there is any desire to derogate + from the position which Ader should occupy in any study of the pioneers of + aeronautical enterprise. If he failed, he failed magnificently, and if he + succeeded, then the student of aeronautics does him an injustice and + confers on the Brothers Wright an honour which, in spite of the value of + their work, they do not deserve. There was one earlier than Ader, Alphonse + Penaud, who, in the face of a lesser disappointment than that which Ader + must have felt in gazing on the wreckage of his machine, committed + suicide; Ader himself, rendered unable to do more, remained content with + his achievement, and with the knowledge that he had played a good part in + the long search which must eventually end in triumph. Whatever the world + might say, he himself was certain that he had achieved flight. This, for + him, was perforce enough. + </p> + <p> + Before turning to consideration of the work accomplished by the Brothers + Wright, and their proved conquest of the air, it is necessary first to + sketch as briefly as may be the experimental work of Sir (then Mr) Hiram + Maxim, who, in his book, Artificial and Natural Flight, has given a fairly + complete account of his various experiments. He began by experimenting + with models, with screw-propelled planes so attached to a horizontal + movable arm that when the screw was set in motion the plane described a + circle round a central point, and, eventually, he built a giant aeroplane + having a total supporting area of 1,500 square feet, and a wing-span of + fifty feet. It has been thought advisable to give a fairly full + description of the power plant used to the propulsion of this machine in + the section devoted to engine development. The aeroplane, as Maxim + describes it, had five long and narrow planes projecting from each side, + and a main or central plane of pterygoid aspect. A fore and aft rudder was + provided, and had all the auxiliary planes been put in position for + experimental work a total lifting surface of 6,000 square feet could have + been obtained. Maxim, however, did not use more than 4,000 square feet of + lifting surface even in his later experiments; with this he judged the + machine capable of lifting slightly under 8,000 lbs. weight, made up of + 600 lbs. water in the boiler and tank, a crew of three men, a supply of + naphtha fuel, and the weight of the machine itself. + </p> + <p> + Maxim's intention was, before attempting free flight, to get as much data + as possible regarding the conditions under which flight must be obtained, + by what is known in these days as 'taxi-ing'—that is, running the + propellers at sufficient speed to drive the machine along the ground + without actually mounting into the air. He knew that he had an immense + lifting surface and a tremendous amount of power in his engine even when + the total weight of the experimental plant was taken into consideration, + and thus he set about to devise some means of keeping the machine on the + nine foot gauge rail track which had been constructed for the trials. At + the outset he had a set of very heavy cast-iron wheels made on which to + mount the machine, the total weight of wheels, axles, and connections + being about one and a half tons. These were so constructed that the light + flanged wheels which supported the machine on the steel rails could be + lifted six inches above the track, still leaving the heavy wheels on the + rails for guidance of the machine. 'This arrangement,' Maxim states, 'was + tried on several occasions, the machine being run fast enough to lift the + forward end off the track. However, I found considerable difficulty in + starting and stopping quickly on account of the great weight, and the + amount of energy necessary to set such heavy wheels spinning at a high + velocity. The last experiment with these wheels was made when a head wind + was blowing at the rate of about ten miles an hour. It was rather + unsteady, and when the machine was running at its greatest velocity, a + sudden gust lifted not only the front end, but also the heavy front wheels + completely off the track, and the machine falling on soft ground was soon + blown over by the wind.' + </p> + <p> + Consequently, a safety track was provided, consisting of squared pine + logs, three inches by nine inches, placed about two feet above the steel + way and having a thirty-foot gauge. Four extra wheels were fitted to the + machine on outriggers and so adjusted that, if the machine should lift one + inch clear of the steel rails, the wheels at the ends of the outriggers + would engage the under side of the pine trackway. + </p> + <p> + The first fully loaded run was made in a dead calm with 150 lbs. steam + pressure to the square inch, and there was no sign of the wheels leaving + the steel track. On a second run, with 230 lbs. steam pressure the machine + seemed to alternate between adherence to the lower and upper tracks, as + many as three of the outrigger wheels engaging at the same time, and the + weight on the steel rails being reduced practically to nothing. In + preparation for a third run, in which it was intended to use full power, a + dynamometer was attached to the machine and the engines were started at + 200 lbs. pressure, which was gradually increased to 310 lbs per square + inch. The incline of the track, added to the reading of the dynamometer, + showed a total screw thrust of 2,164 lbs. After the dynamometer test had + been completed, and everything had been made ready for trial in motion, + careful observers were stationed on each side of the track, and the order + was given to release the machine. What follows is best told in Maxim's own + words:— + </p> + <p> + 'The enormous screw-thrust started the engine so quickly that it nearly + threw the engineers off their feet, and the machine bounded over the track + at a great rate. Upon noticing a slight diminution in the steam pressure, + I turned on more gas, when almost instantly the steam commenced to blow a + steady blast from the small safety valve, showing that the pressure was at + least 320 lbs. in the pipes supplying the engines with steam. Before + starting on this run, the wheels that were to engage the upper track were + painted, and it was the duty of one of my assistants to observe these + wheels during the run, while another assistant watched the pressure gauges + and dynagraphs. The first part of the track was up a slight incline, but + the machine was lifted clear of the lower rails and all of the top wheels + were fully engaged on the upper track when about 600 feet had been + covered. The speed rapidly increased, and when 900 feet had been covered, + one of the rear axle trees, which were of two-inch steel tubing, doubled + up and set the rear end of the machine completely free. The pencils ran + completely across the cylinders of the dynagraphs and caught on the + underneath end. The rear end of the machine being set free, raised + considerably above the track and swayed. At about 1,000 feet, the left + forward wheel also got clear of the upper track, and shortly afterwards + the right forward wheel tore up about 100 feet of the upper track. Steam + was at once shut off and the machine sank directly to the earth, embedding + the wheels in the soft turf without leaving any other marks, showing most + conclusively that the machine was completely suspended in the air before + it settled to the earth. In this accident, one of the pine timbers forming + the upper track went completely through the lower framework of the machine + and broke a number of the tubes, but no damage was done to the machinery + except a slight injury to one of the screws.' + </p> + <p> + It is a pity that the multifarious directions in which Maxim turned his + energies did not include further development of the aeroplane, for it + seems fairly certain that he was as near solution of the problem as Ader + himself, and, but for the holding-down outer track, which was really the + cause of his accident, his machine would certainly have achieved free + flight, though whether it would have risen, flown and alighted, without + accident, is matter for conjecture. + </p> + <p> + The difference between experiments with models and with full-sized + machines is emphasised by Maxim's statement to the effect that with a + small apparatus for ascertaining the power required for artificial flight, + an angle of incidence of one in fourteen was most advantageous, while with + a large machine he found it best to increase his angle to one in eight in + order to get the maximum lifting effect on a short run at a moderate + speed. He computed the total lifting effect in the experiments which led + to the accident as not less than 10,000 lbs., in which is proof that only + his rail system prevented free flight. + </p> + <p> + <a name="link2H_4_0012" id="link2H_4_0012"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + X. SAMUEL PIERPOINT LANGLEY + </h2> + <p> + Langley was an old man when he began the study of aeronautics, or, as he + himself might have expressed it, the study of aerodromics, since he + persisted in calling the series of machines he built 'Aerodromes,' a word + now used only to denote areas devoted to use as landing spaces for flying + machines; the Wright Brothers, on the other hand, had the great gift of + youth to aid them in their work. Even so it was a great race between + Langley, aided by Charles Manly, and Wilbur and Orville Wright, and only + the persistent ill-luck which dogged Langley from the start to the finish + of his experiments gave victory to his rivals. It has been proved + conclusively in these later years of accomplished flight that the machine + which Langley launched on the Potomac River in October of 1903 was fully + capable of sustained flight, and only the accidents incurred in launching + prevented its pilot from being the first man to navigate the air + successfully in a power-driven machine. + </p> + <p> + The best account of Langley's work is that diffused throughout a weighty + tome issued by the Smithsonian Institution, entitled the Langley Memoir on + Mechanical Flight, of which about one-third was written by Langley + himself, the remainder being compiled by Charles M. Manly, the engineer + responsible for the construction of the first radial aero-engine, and + chief assistant to Langley in his experiments. To give a twentieth of the + contents of this volume in the present short account of the development of + mechanical flight would far exceed the amount of space that can be devoted + even to so eminent a man in aeronautics as S. P. Langley, who, apart from + his achievement in the construction of a power-driven aeroplane really + capable of flight, was a scientist of no mean order, and who brought to + the study of aeronautics the skill of the trained investigator allied to + the inventive resource of the genius. + </p> + <p> + That genius exemplified the antique saw regarding the infinite capacity + for taking pains, for the Langley Memoir shows that as early as 1891 + Langley had completed a set of experiments, lasting through years, which + proved it possible to construct machines giving such a velocity to + inclined surfaces that bodies indefinitely heavier than air could be + sustained upon it and propelled through it at high speed. For full account + (very full) of these experiments, and of a later series leading up to the + construction of a series of 'model aerodromes' capable of flight under + power, it is necessary to turn to the bulky memoir of Smithsonian origin. + </p> + <p> + The account of these experiments as given by Langley himself reveals the + humility of the true investigator. Concerning them, Langley remarks that, + 'Everything here has been done with a view to putting a trial aerodrome + successfully in flight within a few years, and thus giving an early + demonstration of the only kind which is conclusive in the eyes of the + scientific man, as well as of the general public—a demonstration + that mechanical flight is possible—by actually flying. All that has + been done has been with an eye principally to this immediate result, and + all the experiments given in this book are to be considered only as + approximations to exact truth. All were made with a view, not to some + remote future, but to an arrival within the compass of a few years at some + result in actual flight that could not be gainsaid or mistaken.' + </p> + <p> + With a series of over thirty rubber-driven models Langley demonstrated the + practicability of opposing curved surfaces to the resistance of the air in + such a way as to achieve flight, in the early nineties of last century; he + then set about finding the motive power which should permit of the + construction of larger machines, up to man-carrying size. The internal + combustion engine was then an unknown quantity, and he had to turn to + steam, finally, as the propulsive energy for his power plant. The chief + problem which faced him was that of the relative weight and power of his + engine; he harked back to the Stringfellow engine of 1868, which in 1889 + came into the possession of the Smithsonian Institution as a historical + curiosity. Rightly or wrongly Langley concluded on examination that this + engine never had developed and never could develop more than a tenth of + the power attributed to it; consequently he abandoned the idea of copying + the Stringfellow design and set about making his own engine. + </p> + <p> + How he overcame the various difficulties that faced him and constructed a + steam-engine capable of the task allotted to it forms a story in itself, + too long for recital here. His first power-driven aerodrome of model size + was begun in November of 1891, the scale of construction being decided + with the idea that it should be large enough to carry an automatic + steering apparatus which would render the machine capable of maintaining a + long and steady flight. The actual weight of the first model far exceeded + the theoretical estimate, and Langley found that a constant increase of + weight under the exigencies of construction was a feature which could + never be altogether eliminated. The machine was made principally of steel, + the sustaining surfaces being composed of silk stretched from a steel tube + with wooden attachments. The first engines were the oscillating type, but + were found deficient in power. This led to the construction of + single-acting inverted oscillating engines with high and low pressure + cylinders, and with admission and exhaust ports to avoid the complication + and weight of eccentric and valves. Boiler and furnace had to be specially + designed; an analysis of sustaining surfaces and the settlement of + equilibrium while in flight had to be overcome, and then it was possible + to set about the construction of the series of model aerodromes and make + test of their 'lift.' + </p> + <p> + By the time Langley had advanced sufficiently far to consider it possible + to conduct experiments in the open air, even with these models, he had got + to his fifth aerodrome, and to the year 1894. Certain tests resulted in + failure, which in turn resulted in further modifications of design, mainly + of the engines. By February of 1895 Langley reported that under favourable + conditions a lift of nearly sixty per cent of the flying weight was + secured, but although this was much more than was required for flight, it + was decided to postpone trials until two machines were ready for the test. + May, 1896, came before actual trials were made, when one machine proved + successful and another, a later design, failed. The difficulty with these + models was that of securing a correct angle for launching; Langley records + how, on launching one machine, it rose so rapidly that it attained an + angle of sixty degrees and then did a tail slide into the water with its + engines working at full speed, after advancing nearly forty feet and + remaining in the air for about three seconds. Here, Langley found that he + had to obtain greater rigidity in his wings, owing to the distortion of + the form of wing under pressure, and how he overcame this difficulty + constitutes yet another story too long for the telling here. + </p> + <p> + Field trials were first attempted in 1893, and Langley blamed his + launching apparatus for their total failure. There was a brief, but at the + same time practical, success in model flight in 1894, extending to between + six and seven seconds, but this only proved the need for strengthening of + the wing. In 1895 there was practically no advance toward the solution of + the problem, but the flights of May 6th and November 28th, 1896, were + notably successful. A diagram given in Langley's memoir shows the track + covered by the aerodrome on these two flights; in the first of them the + machine made three complete circles, covering a distance of 3,200 feet; in + the second, that of November 28th, the distance covered was 4,200 feet, or + about three-quarters of a mile, at a speed of about thirty miles an hour. + </p> + <p> + These achievements meant a good deal; they proved mechanically propelled + flight possible. The difference between them and such experiments as were + conducted by Clement Ader, Maxim, and others, lay principally in the fact + that these latter either did or did not succeed in rising into the air + once, and then, either willingly or by compulsion, gave up the quest, + while Langley repeated his experiments and thus attained to actual proof + of the possibilities of flight. Like these others, however, he decided in + 1896 that he would not undertake the construction of a large man-carrying + machine. In addition to a multitude of actual duties, which left him + practically no time available for original research, he had as an adverse + factor fully ten years of disheartening difficulties in connection with + his model machines. It was President McKinley who, by requesting Langley + to undertake the construction and test of a machine which might finally + lead to the development of a flying machine capable of being used in + warfare, egged him on to his final experiment. Langley's acceptance of the + offer to construct such a machine is contained in a letter addressed from + the Smithsonian Institution on December 12th, 1898, to the Board of + Ordnance and Fortification of the United States War Department; this + letter is of such interest as to render it worthy of reproduction:— + </p> + <p> + 'Gentlemen,—In response to your invitation I repeat what I had the + honour to say to the Board—that I am willing, with the consent of + the Regents of this Institution, to undertake for the Government the + further investigation of the subject of the construction of a flying + machine on a scale capable of carrying a man, the investigation to include + the construction, development and test of such a machine under conditions + left as far as practicable in my discretion, it being understood that my + services are given to the Government in such time as may not be occupied + by the business of the Institution, and without charge. + </p> + <p> + 'I have reason to believe that the cost of the construction will come + within the sum of $50,000.00, and that not more than one-half of that will + be called for in the coming year. + </p> + <p> + 'I entirely agree with what I understand to be the wish of the Board that + privacy be observed with regard to the work, and only when it reaches a + successful completion shall I wish to make public the fact of its success. + </p> + <p> + 'I attach to this a memorandum of my understanding of some points of + detail in order to be sure that it is also the understanding of the Board, + and I am, gentlemen, with much respect, your obedient servant, S. P. + Langley.' + </p> + <p> + One of the chief problems in connection with the construction of a + full-sized apparatus was that of the construction of an engine, for it was + realised from the first that a steam power plant for a full-sized machine + could only be constructed in such a way as to make it a constant menace to + the machine which it was to propel. By this time (1898) the internal + combustion engine had so far advanced as to convince Langley that it + formed the best power plant available. A contract was made for the + delivery of a twelve horse-power engine to weigh not more than a hundred + pounds, but this contract was never completed, and it fell to Charles M. + Manly to design the five-cylinder radial engine, of which a brief account + is included in the section of this work devoted to aero engines, as the + power plant for the Langley machine. + </p> + <p> + The history of the years 1899 to 1903 in the Langley series of experiments + contains a multitude of detail far beyond the scope of this present study, + and of interest mainly to the designer. There were frames, engines, and + propellers, to be considered, worked out, and constructed. We are + concerned here mainly with the completed machine and its trials. Of these + latter it must be remarked that the only two actual field trials which + took place resulted in accidents due to the failure of the launching + apparatus, and not due to any inherent defect in the machine. It was + intended that these two trials should be the first of a series, but the + unfortunate accidents, and the fact that no further funds were forthcoming + for continuance of experiments, prevented Langley's success, which, had he + been free to go through as he intended with his work, would have been + certain. + </p> + <p> + The best brief description of the Langley aerodrome in its final form, and + of the two attempted trials, is contained in the official report of Major + M. M. Macomb of the United States Artillery Corps, which report is here + given in full:— + </p> +<pre xml:space="preserve"> + REPORT +</pre> + <p> + Experiments with working models which were concluded August 8 last having + proved the principles and calculations on which the design of the Langley + aerodrome was based to be correct, the next step was to apply these + principles to the construction of a machine of sufficient size and power + to permit the carrying of a man, who could control the motive power and + guide its flight, thus pointing the way to attaining the final goal of + producing a machine capable of such extensive and precise aerial flight, + under normal atmospheric conditions, as to prove of military or commercial + utility. + </p> + <p> + Mr C. M. Manly, working under Professor Langley, had, by the summer of + 1903, succeeded in completing an engine-driven machine which under + favourable atmospheric conditions was expected to carry a man for any time + up to half an hour, and to be capable of having its flight directed and + controlled by him. + </p> + <p> + The supporting surface of the wings was ample, and experiment showed the + engine capable of supplying more than the necessary motive power. + </p> + <p> + Owing to the necessity of lightness, the weight of the various elements + had to be kept at a minimum, and the factor of safety in construction was + therefore exceedingly small, so that the machine as a whole was delicate + and frail and incapable of sustaining any unusual strain. This defect was + to be corrected in later models by utilising data gathered in future + experiments under varied conditions. + </p> + <p> + One of the most remarkable results attained was the production of a + gasoline engine furnishing over fifty continuous horse-power for a weight + of 120 lbs. + </p> + <p> + The aerodrome, as completed and prepared for test, is briefly described by + Professor Langley as 'built of steel, weighing complete about 730 lbs., + supported by 1,040 feet of sustaining surface, having two propellers + driven by a gas engine developing continuously over fifty brake + horse-power.' + </p> + <p> + The appearance of the machine prepared for flight was exceedingly light + and graceful, giving an impression to all observers of being capable of + successful flight. + </p> + <p> + On October 7 last everything was in readiness, and I witnessed the + attempted trial on that day at Widewater, Va. On the Potomac. The engine + worked well and the machine was launched at about 12.15 p.m. The trial was + unsuccessful because the front guy-post caught in its support on the + launching car and was not released in time to give free flight, as was + intended, but, on the contrary, caused the front of the machine to be + dragged downward, bending the guy-post and making the machine plunge into + the water about fifty yards in front of the house-boat. The machine was + subsequently recovered and brought back to the house-boat. The engine was + uninjured and the frame only slightly damaged, but the four wings and + rudder were practically destroyed by the first plunge and subsequent + towing back to the house-boat. + </p> + <p> + This accident necessitated the removal of the house-boat to Washington for + the more convenient repair of damages. + </p> + <p> + On December 8 last, between 4 and 5 p.m., another attempt at a trial was + made, this time at the junction of the Anacostia with the Potomac, just + below Washington Barracks. + </p> + <p> + On this occasion General Randolph and myself represented the Board of + Ordnance and Fortification. The launching car was released at 4.45 p.m. + being pointed up the Anacostia towards the Navy Yard. My position was on + the tug Bartholdi, about 150 feet from and at right angles to the + direction of proposed flight. The car was set in motion and the propellers + revolved rapidly, the engine working perfectly, but there was something + wrong with the launching. The rear guy-post seemed to drag, bringing the + rudder down on the launching ways, and a crashing, rending sound, followed + by the collapse of the rear wings, showed that the machine had been + wrecked in the launching, just how, it was impossible for me to see. The + fact remains that the rear wings and rudder were wrecked before the + machine was free of the ways. Their collapse deprived the machine of its + support in the rear, and it consequently reared up in front under the + action of the motor, assumed a vertical position, and then toppled over to + the rear, falling into the water a few feet in front of the boat. + </p> + <p> + Mr Manly was pulled out of the wreck uninjured and the wrecked machine—was + subsequently placed upon the house-boat, and the whole brought back to + Washington. + </p> + <p> + From what has been said it will be seen that these unfortunate accidents + have prevented any test of the apparatus in free flight, and the claim + that an engine-driven, man-carrying aerodrome has been constructed lacks + the proof which actual flight alone can give. + </p> + <p> + Having reached the present stage of advancement in its development, it + would seem highly desirable, before laying down the investigation, to + obtain conclusive proof of the possibility of free flight, not only + because there are excellent reasons to hope for success, but because it + marks the end of a definite step toward the attainment of the final goal. + </p> + <p> + Just what further procedure is necessary to secure successful flight with + the large aerodrome has not yet been decided upon. Professor Langley is + understood to have this subject under advisement, and will doubtless + inform the Board of his final conclusions as soon as practicable. + </p> + <p> + In the meantime, to avoid any possible misunderstanding, it should be + stated that even after a successful test of the present great aerodrome, + designed to carry a man, we are still far from the ultimate goal, and it + would seem as if years of constant work and study by experts, together + with the expenditure of thousands of dollars, would still be necessary + before we can hope to produce an apparatus of practical utility on these + lines.—Washington, January 6, 1904. + </p> + <p> + A subsequent report of the Board of ordnance and Fortification to the + Secretary of War embodied the principal points in Major Macomb's report, + but as early as March 3rd, 1904, the Board came to a similar conclusion to + that of the French Ministry of War in respect of Clement Ader's work, + stating that it was not 'prepared to make an additional allotment at this + time for continuing the work.' This decision was in no small measure due + to hostile newspaper criticisms. Langley, in a letter to the press + explaining his attitude, stated that he did not wish to make public the + results of his work till these were certain, in consequence of which he + refused admittance to newspaper representatives, and this attitude + produced a hostility which had effect on the United States Congress. An + offer was made to commercialise the invention, but Langley steadfastly + refused it. Concerning this, Manly remarks that Langley had 'given his + time and his best labours to the world without hope of remuneration, and + he could not bring himself, at his stage of life, to consent to capitalise + his scientific work.' + </p> + <p> + The final trial of the Langley aerodrome was made on December 8th, 1903; + nine days later, on December 17th, the Wright Brothers made their first + flight in a power-propelled machine, and the conquest of the air was thus + achieved. But for the two accidents that spoilt his trials, the honour + which fell to the Wright Brothers would, beyond doubt, have been secured + by Samuel Pierpoint Langley. + </p> + <p> + <a name="link2H_4_0013" id="link2H_4_0013"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + XI. THE WRIGHT BROTHERS + </h2> + <p> + Such information as is given here concerning the Wright Brothers is + derived from the two best sources available, namely, the writings of + Wilbur Wright himself, and a lecture given by Dr Griffith Brewer to + members of the Royal Aeronautical Society. There is no doubt that so far + as actual work in connection with aviation accomplished by the two + brothers is concerned, Wilbur Wright's own statements are the clearest and + best available. Apparently Wilbur was, from the beginning, the historian + of the pair, though he himself would have been the last to attempt to + detract in any way from the fame that his brother's work also deserves. + Throughout all their experiments the two were inseparable, and their work + is one indivisible whole; in fact, in every department of that work, it is + impossible to say where Orville leaves off and where Wilbur begins. + </p> + <p> + It is a great story, this of the Wright Brothers, and one worth all the + detail that can be spared it. It begins on the 16th April, 1867, when + Wilbur Wright was born within eight miles of Newcastle, Indiana. Before + Orville's birth on the 19th August, 1871, the Wright family had moved to + Dayton, Ohio, and settled on what is known as the 'West Side' of the town. + Here the brothers grew up, and, when Orville was still a boy in his teens, + he started a printing business, which, as Griffith Brewer remarks, was + only limited by the smallness of his machine and small quantity of type at + his disposal. This machine was in such a state that pieces of string and + wood were incorporated in it by way of repair, but on it Orville managed + to print a boys' paper which gained considerable popularity in Dayton + 'West Side.' Later, at the age of seventeen, he obtained a more efficient + outfit, with which he launched a weekly newspaper, four pages in size, + entitled The West Side News. After three months' running the paper was + increased in size and Wilbur came into the enterprise as editor, Orville + remaining publisher. In 1894 the two brothers began the publication of a + weekly magazine, Snap-Shots, to which Wilbur contributed a series of + articles on local affairs that gave evidence of the incisive and often + sarcastic manner in which he was able to express himself throughout his + life. Dr Griffith Brewer describes him as a fearless critic, who wrote on + matters of local interest in a kindly but vigorous manner, which did much + to maintain the healthy public municipal life of Dayton. + </p> + <p> + Editorial and publishing enterprise was succeeded by the formation, just + across the road from the printing works, of the Wright Cycle Company, + where the two brothers launched out as cycle manufacturers with the 'Van + Cleve' bicycle, a machine of great local repute for excellence of + construction, and one which won for itself a reputation that lasted long + after it had ceased to be manufactured. The name of the machine was that + of an ancestor of the brothers, Catherine Van Cleve, who was one of the + first settlers at Dayton, landing there from the River Miami on April 1st, + 1796, when the country was virgin forest. + </p> + <p> + It was not until 1896 that the mechanical genius which characterised the + two brothers was turned to the consideration of aeronautics. In that year + they took up the problem thoroughly, studying all the aeronautical + information then in print. Lilienthal's writings formed one basis for + their studies, and the work of Langley assisted in establishing in them a + confidence in the possibility of a solution to the problems of mechanical + flight. In 1909, at the banquet given by the Royal Aero Club to the Wright + Brothers on their return to America, after the series of demonstration + flights carried out by Wilbur Wright on the Continent, Wilbur paid tribute + to the great pioneer work of Stringfellow, whose studies and achievements + influenced his own and Orville's early work. He pointed out how + Stringfellow devised an aeroplane having two propellers and vertical and + horizontal steering, and gave due place to this early pioneer of + mechanical flight. + </p> + <p> + Neither of the brothers was content with mere study of the work of others. + They collected all the theory available in the books published up to that + time, and then built man-carrying gliders with which to test the data of + Lilienthal and such other authorities as they had consulted. For two years + they conducted outdoor experiments in order to test the truth or otherwise + of what were enunciated as the principles of flight; after this they + turned to laboratory experiments, constructing a wind tunnel in which they + made thousands of tests with models of various forms of curved planes. + From their experiments they tabulated thousands of readings, which + Griffith Brewer remarks as giving results equally efficient with those of + the elaborate tables prepared by learned institutions. + </p> + <p> + Wilbur Wright has set down the beginnings of the practical experiments + made by the two brothers very clearly. 'The difficulties,' he says, 'which + obstruct the pathway to success in flying machine construction are of + three general classes: (1) Those which relate to the construction of the + sustaining wings; (2) those which relate to the generation and application + of the power required to drive the machine through the air; (3) those + relating to the balancing and steering of the machine after it is actually + in flight. Of these difficulties two are already to a certain extent + solved. Men already know how to construct wings, or aeroplanes, which, + when driven through the air at sufficient speed, will not only sustain the + weight of the wings themselves, but also that of the engine and the + engineer as well. Men also know how to build engines and' screws of + sufficient lightness and power to drive these planes at sustaining speed. + Inability to balance and steer still confronts students of the flying + problem, although nearly ten years have passed (since Lilienthal's + success). When this one feature has been worked out, the age of flying + machines will have arrived, for all other difficulties are of minor + importance. + </p> + <p> + 'The person who merely watches the flight of a bird gathers the impression + that the bird has nothing to think of but the flapping of its wings. As a + matter of fact, this is a very small part of its mental labour. Even to + mention all the things the bird must constantly keep in mind in order to + fly securely through the air would take a considerable time. If I take a + piece of paper and, after placing it parallel with the ground, quickly let + it fall, it will not settle steadily down as a staid, sensible piece of + paper ought to do, but it insists on contravening every recognised rule of + decorum, turning over and darting hither and thither in the most erratic + manner, much after the style of an untrained horse. Yet this is the style + of steed that men must learn to manage before flying can become an + everyday sport. The bird has learned this art of equilibrium, and learned + it so thoroughly that its skill is not apparent to our sight. We only + learn to appreciate it when we can imitate it. + </p> + <p> + 'Now, there are only two ways of learning to ride a fractious horse: one + is to get on him and learn by actual practice how each motion and trick + may be best met; the other is to sit on a fence and watch the beast + awhile, and then retire to the house and at leisure figure out the best + way of overcoming his jumps and kicks. The latter system is the safer, but + the former, on the whole, turns out the larger proportion of good riders. + It is very much the same in learning to ride a flying machine; if you are + looking for perfect safety you will do well to sit on a fence and watch + the birds, but if you really wish to learn you must mount a machine and + become acquainted with its tricks by actual trial. The balancing of a + gliding or flying machine is very simple in theory. It merely consists in + causing the centre of pressure to coincide with the centre of gravity.' + </p> + <p> + These comments are taken from a lecture delivered by Wilbur Wright before + the Western Society of Engineers in September of 1901, under the + presidency of Octave Chanute. In that lecture Wilbur detailed the way in + which he and his brother came to interest themselves in aeronautical + problems and constructed their first glider. He speaks of his own notice + of the death of Lilienthal in 1896, and of the way in which this fatality + roused him to an active interest in aeronautical problems, which was + stimulated by reading Professor Marey's Animal Mechanism, not for the + first time. 'From this I was led to read more modern works, and as my + brother soon became equally interested with myself, we soon passed from + the reading to the thinking, and finally to the working stage. It seemed + to us that the main reason why the problem had remained so long unsolved + was that no one had been able to obtain any adequate practice. We figured + that Lilienthal in five years of time had spent only about five hours in + actual gliding through the air. The wonder was not that he had done so + little, but that he had accomplished so much. It would not be considered + at all safe for a bicycle rider to attempt to ride through a crowded city + street after only five hours' practice, spread out in bits of ten seconds + each over a period of five years; yet Lilienthal with this brief practice + was remarkably successful in meeting the fluctuations and eddies of + wind-gusts. We thought that if some method could be found by which it + would be possible to practice by the hour instead of by the second there + would be hope of advancing the solution of a very difficult problem. It + seemed feasible to do this by building a machine which would be sustained + at a speed of eighteen miles per hour, and then finding a locality where + winds of this velocity were common. With these conditions a rope attached + to the machine to keep it from floating backward would answer very nearly + the same purpose as a propeller driven by a motor, and it would be + possible to practice by the hour, and without any serious danger, as it + would not be necessary to rise far from the ground, and the machine would + not have any forward motion at all. We found, according to the accepted + tables of air pressure on curved surfaces, that a machine spreading 200 + square feet of wing surface would be sufficient for our purpose, and that + places would easily be found along the Atlantic coast where winds of + sixteen to twenty-five miles were not at all uncommon. When the winds were + low it was our plan to glide from the tops of sandhills, and when they + were sufficiently strong to use a rope for our motor and fly over one + spot. Our next work was to draw up the plans for a suitable machine. After + much study we finally concluded that tails were a source of trouble rather + than of assistance, and therefore we decided to dispense with them + altogether. It seemed reasonable that if the body of the operator could be + placed in a horizontal position instead of the upright, as in the machines + of Lilienthal, Pilcher, and Chanute, the wind resistance could be very + materially reduced, since only one square foot instead of five would be + exposed. As a full half horse-power would be saved by this change, we + arranged to try at least the horizontal position. Then the method of + control used by Lilienthal, which consisted in shifting the body, did not + seem quite as quick or effective as the case required; so, after long + study, we contrived a system consisting of two large surfaces on the + Chanute double-deck plan, and a smaller surface placed a short distance in + front of the main surfaces in such a position that the action of the wind + upon it would counterbalance the effect of the travel of the centre of + pressure on the main surfaces. Thus changes in the direction and velocity + of the wind would have little disturbing effect, and the operator would be + required to attend only to the steering of the machine, which was to be + effected by curving the forward surface up or down. The lateral + equilibrium and the steering to right or left was to be attained by a + peculiar torsion of the main surfaces which was equivalent to presenting + one end of the wings at a greater angle than the other. In the main frame + a few changes were also made in the details of construction and trussing + employed by Mr Chanute. The most important of these were: (1) The moving + of the forward main crosspiece of the frame to the extreme front edge; (2) + the encasing in the cloth of all crosspieces and ribs of the surfaces; (3) + a rearrangement of the wires used in trussing the two surfaces together, + which rendered it possible to tighten all the wires by simply shortening + two of them.' + </p> + <p> + The brothers intended originally to get 200 square feet of supporting + surface for their glider, but the impossibility of obtaining suitable + material compelled them to reduce the area to 165 square feet, which, by + the Lilienthal tables, admitted of support in a wind of about twenty-one + miles an hour at an angle of three degrees. With this glider they went in + the summer of I 1900 to the little settlement of Kitty Hawk, North + Carolina, situated on the strip of land dividing Albemarle Sound from the + Atlantic. Here they reckoned on obtaining steady wind, and here, on the + day that they completed the machine, they took it out for trial as a kite + with the wind blowing at between twenty-five and thirty miles an hour. + They found that in order to support a man on it the glider required an + angle nearer twenty degrees than three, and even with the wind at thirty + miles an hour they could not get down to the planned angle of three + degrees. 'Later, when the wind was too light to support the machine with a + man on it, they tested it as a kite, working the rudders by cords. + Although they obtained satisfactory results in this way they realised + fully that actual gliding experience was necessary before the tests could + be considered practical. + </p> + <p> + A series of actual measurements of lift and drift of the machine gave + astonishing results. 'It appeared that the total horizontal pull of the + machine, while sustaining a weight of 52 lbs., was only 8.5 lbs., which + was less than had been previously estimated for head resistance of the + framing alone. Making allowance for the weight carried, it appeared that + the head resistance of the framing was but little more than fifty per cent + of the amount which Mr Chanute had estimated as the head resistance of the + framing of his machine. On the other hand, it appeared sadly deficient in + lifting power as compared with the calculated lift of curved surfaces of + its size... we decided to arrange our machine for the following year so + that the depth of curvature of its surfaces could be varied at will, and + its covering air-proofed.' + </p> + <p> + After these experiments the brothers decided to turn to practical gliding, + for which they moved four miles to the south, to the Kill Devil sandhills, + the principal of which is slightly over a hundred feet in height, with an + inclination of nearly ten degrees on its main north-western slope. On the + day after their arrival they made about a dozen glides, in which, although + the landings were made at a speed of more than twenty miles an hour, no + injury was sustained either by the machine or by the operator. + </p> + <p> + 'The slope of the hill was 9.5 degrees, or a drop of one foot in six. We + found that after attaining a speed of about twenty-five to thirty miles + with reference to the wind, or ten to fifteen miles over the ground, the + machine not only glided parallel to the slope of the hill, but greatly + increased its speed, thus indicating its ability to glide on a somewhat + less angle than 9.5 degrees, when we should feel it safe to rise higher + from the surface. The control of the machine proved even better than we + had dared to expect, responding quickly to the slightest motion of the + rudder. With these glides our experiments for the year 1900 closed. + Although the hours and hours of practice we had hoped to obtain finally + dwindled down to about two minutes, we were very much pleased with the + general results of the trip, for, setting out as we did with almost + revolutionary theories on many points and an entirely untried form of + machine, we considered it quite a point to be able to return without + having our pet theories completely knocked on the head by the hard logic + of experience, and our own brains dashed out in the bargain. Everything + seemed to us to confirm the correctness of our original opinions: (1) That + practice is the key to the secret of flying; (2) that it is practicable to + assume the horizontal position; (3) that a smaller surface set at a + negative angle in front of the main bearing surfaces, or wings, will + largely counteract the effect of the fore and aft travel of the centre of + pressure; (4) that steering up and down can be attained with a rudder + without moving the position of the operator's body; (5) that twisting the + wings so as to present their ends to the wind at different angles is a + more prompt and efficient way of maintaining lateral equilibrium than + shifting the body of the operator.' + </p> + <p> + For the gliding experiments of 1901 it was decided to retain the form of + the 1900 glider, but to increase the area to 308 square feet, which, the + brothers calculated, would support itself and its operator in a wind of + seventeen miles an hour with an angle of incidence of three degrees. Camp + was formed at Kitty Hawk in the middle of July, and on July 27th the + machine was completed and tried for the first time in a wind of about + fourteen miles an hour. The first attempt resulted in landing after a + glide of only a few yards, indicating that the centre of gravity was too + far in front of the centre of pressure. By shifting his position farther + and farther back the operator finally achieved an undulating flight of a + little over 300 feet, but to obtain this success he had to use full power + of the rudder to prevent both stalling and nose-diving. With the 1900 + machine one-fourth of the rudder action had been necessary for far better + control. + </p> + <p> + Practically all glides gave the same result, and in one the machine rose + higher and higher until it lost all headway. 'This was the position from + which Lilienthal had always found difficulty in extricating himself, as + his machine then, in spite of his greatest exertions, manifested a + tendency to dive downward almost vertically and strike the ground head on + with frightful velocity. In this case a warning cry from the ground caused + the operator to turn the rudder to its full extent and also to move his + body slightly forward. The machine then settled slowly to the ground, + maintaining its horizontal position almost perfectly, and landed without + any injury at all. This was very encouraging, as it showed that one of the + very greatest dangers in machines with horizontal tails had been overcome + by the use of the front rudder. Several glides later the same experience + was repeated with the same result. In the latter case the machine had even + commenced to move backward, but was nevertheless brought safely to the + ground in a horizontal position. On the whole this day's experiments were + encouraging, for while the action of the rudder did not seem at all like + that of our 1900 machine, yet we had escaped without difficulty from + positions which had proved very dangerous to preceding experimenters, and + after less than one minute's actual practice had made a glide of more than + 300 feet, at an angle of descent of ten degrees, and with a machine nearly + twice as large as had previously been considered safe. The trouble with + its control, which has been mentioned, we believed could be corrected when + we should have located its cause.' + </p> + <p> + It was finally ascertained that the defect could be remedied by trussing + down the ribs of the whole machine so as to reduce the depth of curvature. + When this had been done gliding was resumed, and after a few trials glides + of 366 and 389 feet were made with prompt response on the part of the + machine, even to small movements of the rudder. The rest of the story of + the gliding experiments of 1901 cannot be better told than in Wilbur + Wright's own words, as uttered by him in the lecture from which the + foregoing excerpts have been made. + </p> + <p> + 'The machine, with its new curvature, never failed to respond promptly to + even small movements of the rudder. The operator could cause it to almost + skim the ground, following the undulations of its surface, or he could + cause it to sail out almost on a level with the starting point, and, + passing high above the foot of the hill, gradually settle down to the + ground. The wind on this day was blowing eleven to fourteen miles per + hour. The next day, the conditions being favourable, the machine was again + taken out for trial. This time the velocity of the wind was eighteen to + twenty-two miles per hour. At first we felt some doubt as to the safety of + attempting free flight in so strong a wind, with a machine of over 300 + square feet and a practice of less than five minutes spent in actual + flight. But after several preliminary experiments we decided to try a + glide. The control of the machine seemed so good that we then felt no + apprehension in sailing boldly forth. And thereafter we made glide after + glide, sometimes following the ground closely and sometimes sailing high + in the air. Mr Chanute had his camera with him and took pictures of some + of these glides, several of which are among those shown. + </p> + <p> + 'We made glides on subsequent days, whenever the conditions were + favourable. The highest wind thus experimented in was a little over twelve + metres per second—nearly twenty-seven miles per hour. + </p> + <p> + It had been our intention when building the machine to do the larger part + of the experimenting in the following manner:—When the wind blew + seventeen miles an hour, or more, we would attach a rope to the machine + and let it rise as a kite with the operator upon it. When it should reach + a proper height the operator would cast off the rope and glide down to the + ground just as from the top of a hill. In this way we would be saved the + trouble of carrying the machine uphill after each glide, and could make at + least ten glides in the time required for one in the other way. But when + we came to try it, we found that a wind of seventeen miles, as measured by + Richards' anemometer, instead of sustaining the machine with its operator, + a total weight of 240 lbs., at an angle of incidence of three degrees, in + reality would not sustain the machine alone—100 lbs.—at this + angle. Its lifting capacity seemed scarcely one third of the calculated + amount. In order to make sure that this was not due to the porosity of the + cloth, we constructed two small experimental surfaces of equal size, one + of which was air-proofed and the other left in its natural state; but we + could detect no difference in their lifting powers. For a time we were led + to suspect that the lift of curved surfaces very little exceeded that of + planes of the same size, but further investigation and experiment led to + the opinion that (1) the anemometer used by us over-recorded the true + velocity of the wind by nearly 15 per cent; (2) that the well-known + Smeaton co-efficient of.005 V squared for the wind pressure at 90 degrees + is probably too great by at least 20 per cent; (3) that Lilienthal's + estimate that the pressure on a curved surface having an angle of + incidence of 3 degrees equals.545 of the pressure at go degrees is too + large, being nearly 50 per cent greater than very recent experiments of + our own with a pressure testing-machine indicate; (4) that the + superposition of the surfaces somewhat reduced the lift per square foot, + as compared with a single surface of equal area. + </p> + <p> + 'In gliding experiments, however, the amount of lift is of less relative + importance than the ratio of lift to drift, as this alone decides the + angle of gliding descent. In a plane the pressure is always perpendicular + to the surface, and the ratio of lift to drift is therefore the same as + that of the cosine to the sine of the angle of incidence. But in curved + surfaces a very remarkable situation is found. The pressure, instead of + being uniformly normal to the chord of the arc, is usually inclined + considerably in front of the perpendicular. The result is that the lift is + greater and the drift less than if the pressure were normal. Lilienthal + was the first to discover this exceedingly important fact, which is fully + set forth in his book, Bird Flight the Basis of the Flying Art, but owing + to some errors in the methods he used in making measurements, question was + raised by other investigators not only as to the accuracy of his figures, + but even as to the existence of any tangential force at all. Our + experiments confirm the existence of this force, though our measurements + differ considerably from those of Lilienthal. While at Kitty Hawk we spent + much time in measuring the horizontal pressure on our unloaded machine at + various angles of incidence. We found that at 13 degrees the horizontal + pressure was about 23 lbs. This included not only the drift proper, or + horizontal component of the pressure on the side of the surface, but also + the head resistance of the framing as well. The weight of the machine at + the time of this test was about 108 lbs. Now, if the pressure had been + normal to the chord of the surface, the drift proper would have been to + the lift (108 lbs.) as the sine of 13 degrees is to the cosine of 13 + degrees, or.22 X 108/.97 = 24+ lbs.; but this slightly exceeds the total + pull of 23 pounds on our scales. Therefore it is evident that the average + pressure on the surface, instead of being normal to the chord, was so far + inclined toward the front that all the head resistance of framing and + wires used in the construction was more than overcome. In a wind of + fourteen miles per hour resistance is by no means a negligible factor, so + that tangential is evidently a force of considerable value. In a higher + wind, which sustained the machine at an angle of 10 degrees the pull on + the scales was 18 lbs. With the pressure normal to the chord the drift + proper would have been 17 X 98/.98. The travel of the centre of pressure + made it necessary to put sand on the front rudder to bring the centres of + gravity and pressure into coincidence, consequently the weight of the + machine varied from 98 lbs. to 108 lbs. in the different tests= 17 lbs., + so that, although the higher wind velocity must have caused an increase in + the head resistance, the tangential force still came within 1 lb. of + overcoming it. After our return from Kitty Hawk we began a series of + experiments to accurately determine the amount and direction of the + pressure produced on curved surfaces when acted upon by winds at the + various angles from zero to 90 degrees. These experiments are not yet + concluded, but in general they support Lilienthal in the claim that the + curves give pressures more favourable in amount and direction than planes; + but we find marked differences in the exact values, especially at angles + below 10 degrees. We were unable to obtain direct measurements of the + horizontal pressures of the machine with the operator on board, but by + comparing the distance travelled with the vertical fall, it was easily + calculated that at a speed of 24 miles per hour the total horizontal + resistances of our machine, when bearing the operator, amounted to 40 + lbs., which is equivalent to about 2 1/3 horse-power. It must not be + supposed, however, that a motor developing this power would be sufficient + to drive a man-bearing machine. The extra weight of the motor would + require either a larger machine, higher speed, or a greater angle of + incidence in order to support it, and therefore more power. It is + probable, however, that an engine of 6 horse-power, weighing 100 lbs. + would answer the purpose. Such an engine is entirely practicable. Indeed, + working motors of one-half this weight per horse-power (9 lbs. per + horse-power) have been constructed by several different builders. + Increasing the speed of our machine from 24 to 33 miles per hour reduced + the total horizontal pressure from 40 to about 35 lbs. This was quite an + advantage in gliding, as it made it possible to sail about 15 per cent + farther with a given drop. However, it would be of little or no advantage + in reducing the size of the motor in a power-driven machine, because the + lessened thrust would be counterbalanced by the increased speed per + minute. Some years ago Professor Langley called attention to the great + economy of thrust which might be obtained by using very high speeds, and + from this many were led to suppose that high speed was essential to + success in a motor-driven machine. But the economy to which Professor + Langley called attention was in foot pounds per mile of travel, not in + foot pounds per minute. It is the foot pounds per minute that fixes the + size of the motor. The probability is that the first flying machines will + have a relatively low speed, perhaps not much exceeding 20 miles per hour, + but the problem of increasing the speed will be much simpler in some + respects than that of increasing the speed of a steamboat; for, whereas in + the latter case the size of the engine must increase as the cube of the + speed, in the flying machine, until extremely high speeds are reached, the + capacity of the motor increases in less than simple ratio; and there is + even a decrease in the fuel per mile of travel. In other words, to double + the speed of a steamship (and the same is true of the balloon type of + airship) eight times the engine and boiler capacity would be required, and + four times the fuel consumption per mile of travel: while a flying machine + would require engines of less than double the size, and there would be an + actual decrease in the fuel consumption per mile of travel. But looking at + the matter conversely, the great disadvantage of the flying machine is + apparent; for in the latter no flight at all is possible unless the + proportion of horse-power to flying capacity is very high; but on the + other hand a steamship is a mechanical success if its ratio of horse-power + to tonnage is insignificant. A flying machine that would fly at a speed of + 50 miles per hour with engines of 1,000 horse-power would not be upheld by + its wings at all at a speed of less than 25 miles an hour, and nothing + less than 500 horse-power could drive it at this speed. But a boat which + could make 40 miles an hour with engines of 1,000 horse-power would still + move 4 miles an hour even if the engines were reduced to 1 horse-power. + The problems of land and water travel were solved in the nineteenth + century, because it was possible to begin with small achievements, and + gradually work up to our present success. The flying problem was left over + to the twentieth century, because in this case the art must be highly + developed before any flight of any considerable duration at all can be + obtained. + </p> + <p> + 'However, there is another way of flying which requires no artificial + motor, and many workers believe that success will come first by this road. + I refer to the soaring flight, by which the machine is permanently + sustained in the air by the same means that are employed by soaring birds. + They spread their wings to the wind, and sail by the hour, with no + perceptible exertion beyond that required to balance and steer themselves. + What sustains them is not definitely known, though it is almost certain + that it is a rising current of air. But whether it be a rising current or + something else, it is as well able to support a flying machine as a bird, + if man once learns the art of utilising it. In gliding experiments it has + long been known that the rate of vertical descent is very much retarded, + and the duration of the flight greatly prolonged, if a strong wind blows + UP the face of the hill parallel to its surface. Our machine, when gliding + in still air, has a rate of vertical descent of nearly 6 feet per second, + while in a wind blowing 26 miles per hour up a steep hill we made glides + in which the rate of descent was less than 2 feet per second. And during + the larger part of this time, while the machine remained exactly in the + rising current, THERE WAS NO DESCENT AT ALL, BUT EVEN A SLIGHT RISE. If + the operator had had sufficient skill to keep himself from passing beyond + the rising current he would have been sustained indefinitely at a higher + point than that from which he started. The illustration shows one of these + very slow glides at a time when the machine was practically at a + standstill. The failure to advance more rapidly caused the photographer + some trouble in aiming, as you will perceive. In looking at this picture + you will readily understand that the excitement of gliding experiments + does not entirely cease with the breaking up of camp. In the photographic + dark-room at home we pass moments of as thrilling interest as any in the + field, when the image begins to appear on the plate and it is yet an open + question whether we have a picture of a flying machine or merely a patch + of open sky. These slow glides in rising current probably hold out greater + hope of extensive practice than any other method within man's reach, but + they have the disadvantage of requiring rather strong winds or very large + supporting surfaces. However, when gliding operators have attained greater + skill, they can with comparative safety maintain themselves in the air for + hours at a time in this way, and thus by constant practice so increase + their knowledge and skill that they can rise into the higher air and + search out the currents which enable the soaring birds to transport + themselves to any desired point by first rising in a circle and then + sailing off at a descending angle. This illustration shows the machine, + alone, flying in a wind of 35 miles per hour on the face of a steep hill, + 100 feet high. It will be seen that the machine not only pulls upward, but + also pulls forward in the direction from which the wind blows, thus + overcoming both gravity and the speed of the wind. We tried the same + experiment with a man on it, but found danger that the forward pull would + become so strong, that the men holding the ropes would be dragged from + their insecure foothold on the slope of the hill. So this form of + experimenting was discontinued after four or five minutes' trial. + </p> + <p> + 'In looking over our experiments of the past two years, with models and + full-size machines, the following points stand out with clearness:— + </p> + <p> + '1. That the lifting power of a large machine, held stationary in a wind + at a small distance from the earth, is much less than the Lilienthal table + and our own laboratory experiments would lead us to expect. When the + machine is moved through the air, as in gliding, the discrepancy seems + much less marked. + </p> + <p> + '2. That the ratio of drift to lift in well-shaped surfaces is less at + angles of incidence of 5 degrees to 12 degrees than at an angle of 3 + degrees. + </p> + <p> + '3. That in arched surfaces the centre of pressure at 90 degrees is near + the centre of the surface, but moves slowly forward as the angle becomes + less, till a critical angle varying with the shape and depth of the curve + is reached, after which it moves rapidly toward the rear till the angle of + no lift is found. + </p> + <p> + '4. That with similar conditions large surfaces may be controlled with not + much greater difficulty than small ones, if the control is effected by + manipulation of the surfaces themselves, rather than by a movement of the + body of the operator. + </p> + <p> + '5. That the head resistances of the framing can be brought to a point + much below that usually estimated as necessary. + </p> + <p> + '6. That tails, both vertical and horizontal, may with safety be + eliminated in gliding and other flying experiments. + </p> + <p> + '7. That a horizontal position of the operator's body may be assumed + without excessive danger, and thus the head resistance reduced to about + one-fifth that of the upright position. + </p> + <p> + '8. That a pair of superposed, or tandem surfaces, has less lift in + proportion to drift than either surface separately, even after making + allowance for weight and head resistance of the connections.' + </p> + <p> + Thus, to the end of the 1901 experiments, Wilbur Wright provided a fairly + full account of what was accomplished; the record shows an amount of + patient and painstaking work almost beyond belief—it was no question + of making a plane and launching it, but a business of trial and error, + investigation and tabulation of detail, and the rejection time after time + of previously accepted theories, till the brothers must have felt the the + solid earth was no longer secure, at times. Though it was Wilbur who set + down this and other records of the work done, yet the actual work was so + much Orville's as his brother's that no analysis could separate any set of + experiments and say that Orville did this and Wilbur that—the two + were inseparable. On this point Griffith Brewer remarked that 'in the + arguments, if one brother took one view, the other brother took the + opposite view as a matter of course, and the subject was thrashed to + pieces until a mutually acceptable result remained. I have often been + asked since these pioneer days, "Tell me, Brewer, who was really the + originator of those two?" In reply, I used first to say, "I think it was + mostly Wilbur," and later, when I came to know Orville better, I said, + "The thing could not have been without Orville." Now, when asked, I have + to say, "I don't know," and I feel the more I think of it that it was only + the wonderful combination of these two brothers, who devoted their lives + together or this common object, that made the discovery of the art of + flying possible.' + </p> + <p> + Beyond the 1901 experiments in gliding, the record grows more scrappy, + less detailed. It appears that once power-driven flight had been achieved, + the brothers were not so willing to talk as before; considering the amount + of work that they put in, there could have been little time for verbal + description of that work—as already remarked, their tables still + stand for the designer and experimenter. The end of the 1901 experiments + left both brothers somewhat discouraged, though they had accomplished more + than any others. 'Having set out with absolute faith in the existing + scientific data, we ere driven to doubt one thing after another, finally, + after two years of experiment, we cast it all aside, and decided to rely + entirely on our own investigations. Truth and error were everywhere so + intimately mixed as to be indistinguishable.... We had taken up + aeronautics as a sport. We reluctantly entered upon the scientific side of + it.' + </p> + <p> + Yet, driven thus to the more serious aspect of the work, they found in the + step its own reward, for the work of itself drew them on and on, to the + construction of measuring machines for the avoidance of error, and to the + making of series after series of measurements, concerning which Wilbur + wrote in 1908 (in the Century Magazine) that 'after making preliminary + measurements on a great number of different shaped surfaces, to secure a + general understanding of the subject, we began systematic measurements of + standard surfaces, so varied in design as to bring out the underlying + causes of differences noted in their pressures. Measurements were + tabulated on nearly fifty of these at all angles from zero to 45 degrees, + at intervals of 2 1/2 degrees. Measurements were also secured showing the + effects on each other when surfaces are superposed, or when they follow + one another. + </p> + <p> + 'Some strange results were obtained. One surface, with a heavy roll at the + front edge, showed the same lift for all angles from 7 1/2 to 45 degrees. + This seemed so anomalous that we were almost ready to doubt our own + measurements, when a simple test was suggested. A weather vane, with two + planes attached to the pointer at an angle of 80 degrees with each other, + was made. According to our table, such a vane would be in unstable + equilibrium when pointing directly into the wind, for if by chance the + wind should happen to strike one plane at 39 degrees and the other at 41 + degrees, the plane with the smaller angle would have the greater pressure + and the pointer would be turned still farther out of the course of the + wind until the two vanes again secured equal pressures, which would be at + approximately 30 and 50 degrees. But the vane performed in this very + manner. Further corroboration of the tables was obtained in experiments + with the new glider at Kill Devil Hill the next season. + </p> + <p> + 'In September and October, 1902 nearly 1,000 gliding flights were made, + several of which covered distances of over 600 feet. Some, made against a + wind of 36 miles an hour, gave proof of the effectiveness of the devices + for control. With this machine, in the autumn of 1903, we made a number of + flights in which we remained in the air for over a minute, often soaring + for a considerable time in one spot, without any descent at all. Little + wonder that our unscientific assistant should think the only thing needed + to keep it indefinitely in the air would be a coat of feathers to make it + light!' + </p> + <p> + It was at the conclusion of these experiments of 1903 that the brothers + concluded they had obtained sufficient data from their thousands of glides + and multitude of calculations to permit of their constructing and making + trial of a power-driven machine. The first designs got out provided for a + total weight of 600 lbs., which was to include the weight of the motor and + the pilot; but on completion it was found that there was a surplus of + power from the motor, and thus they had 150 lbs. weight to allow for + strengthening wings and other parts. + </p> + <p> + They came up against the problem to which Riach has since devoted so much + attention, that of propeller design. 'We had thought of getting the theory + of the screw-propeller from the marine engineers, and then, by applying + our table of air-pressures to their formulae, of designing air-propellers + suitable for our uses. But, so far as we could learn, the marine engineers + possessed only empirical formulae, and the exact action of the screw + propeller, after a century of use, was still very obscure. As we were not + in a position to undertake a long series of practical experiments to + discover a propeller suitable for our machine, it seemed necessary to + obtain such a thorough understanding of the theory of its reactions as + would enable us to design them from calculation alone. What at first + seemed a simple problem became more complex the longer we studied it. With + the machine moving forward, the air flying backward, the propellers + turning sidewise, and nothing standing still, it seemed impossible to find + a starting point from which to trace the various simultaneous reactions. + Contemplation of it was confusing. After long arguments we often found + ourselves in the ludicrous position of each having been converted to the + other's side, with no more agreement than when the discussion began. + </p> + <p> + 'It was not till several months had passed, and every phase of the problem + had been thrashed over and over, that the various reactions began to + untangle themselves. When once a clear understanding had been obtained + there was no difficulty in designing a suitable propeller, with proper + diameter, pitch, and area of blade, to meet the requirements of the flier. + High efficiency in a screw-propeller is not dependent upon any particular + or peculiar shape, and there is no such thing as a "best" screw. A + propeller giving a high dynamic efficiency when used upon one machine may + be almost worthless when used upon another. The propeller should in every + case be designed to meet the particular conditions of the machine to which + it is to be applied. Our first propellers, built entirely from + calculation, gave in useful work 66 per cent of the power expended. This + was about one-third more than had been secured by Maxim or Langley.' + </p> + <p> + Langley had made his last attempt with the 'aerodrome,' and his splendid + failure but a few days before the brothers made their first attempt at + power-driven aeroplane flight. On December 17th, 1903, the machine was + taken out; in addition to Wilbur and Orville Wright, there were present + five spectators: Mr A. D. Etheridge, of the Kill Devil life-saving + station; Mr W. S.Dough, Mr W. C. Brinkley, of Manteo; Mr John Ward, of + Naghead, and Mr John T. Daniels.[*] A general invitation had been given to + practically all the residents in the vicinity, but the Kill Devil district + is a cold area in December, and history had recorded so many experiments + in which machines had failed to leave the ground that between temperature + and scepticism only these five risked a waste of their time. + </p> + <p> + [*] This list is as given by Wilbur Wright himself. + </p> + <p> + And these five were in at the greatest conquest man had made since James + Watt evolved the steam engine—perhaps even a greater conquest than + that of Watt. Four flights in all were made; the first lasted only twelve + seconds, 'the first in the history of the world in which a machine + carrying a man had raised itself into the air by its own power in free + flight, had sailed forward on a level course without reduction of speed, + and had finally landed without being wrecked,' said Wilbur Wright + concerning the achievement.[*] The next two flights were slightly longer, + and the fourth and last of the day was one second short of the complete + minute; it was made into the teeth of a 20 mile an hour wind, and the + distance travelled was 852 feet. + </p> + <p> + [*] Century Magazine, September, 1908. + </p> + <p> + This bald statement of the day's doings is as Wilbur Wright himself has + given it, and there is in truth nothing more to say; no amount of + statement could add to the importance of the achievement, and no more than + the bare record is necessary. The faith that had inspired the long roll of + pioneers, from da Vinci onward, was justified at last. + </p> + <p> + Having made their conquest, the brothers took the machine back to camp, + and, as they thought, placed it in safety. Talking with the little group + of spectators about the flights, they forgot about the machine, and then a + sudden gust of wind struck it. Seeing that it was being overturned, all + made a rush toward it to save it, and Mr Daniels, a man of large + proportions, was in some way lifted off his feet, falling between the + planes. The machine overturned fully, and Daniels was shaken like a die in + a cup as the wind rolled the machine over and over—he came out at + the end of his experience with a series of bad bruises, and no more, but + the damage done to the machine by the accident was sufficient to render it + useless for further experiment that season. + </p> + <p> + A new machine, stronger and heavier, was constructed by the brothers, and + in the spring of 1904 they began experiments again at Sims Station, eight + miles to the east of Dayton, their home town. Press representatives were + invited for the first trial, and about a dozen came—the whole + gathering did not number more than fifty people. 'When preparations had + been concluded,' Wilbur Wright wrote of this trial, 'a wind of only three + or four miles an hour was blowing—insufficient for starting on so + short a track—but since many had come a long way to see the machine + in action, an attempt was made. To add to the other difficulty, the engine + refused to work properly. The machine, after running the length of the + track, slid off the end without rising into the air at all. Several of the + newspaper men returned next day but were again disappointed. The engine + performed badly, and after a glide of only sixty feet the machine again + came to the ground. Further trial was postponed till the motor could be + put in better running condition. The reporters had now, no doubt, lost + confidence in the machine, though their reports, in kindness, concealed + it. Later, when they heard that we were making flights of several minutes' + duration, knowing that longer flights had been made with airships, and not + knowing any essential difference between airships and flying machines, + they were but little interested. + </p> + <p> + 'We had not been flying long in 1904 before we found that the problem of + equilibrium had not as yet been entirely solved. Sometimes, in making a + circle, the machine would turn over sidewise despite anything the operator + could do, although, under the same conditions in ordinary straight flight + it could have been righted in an instant. In one flight, in 1905, while + circling round a honey locust-tree at a height of about 50 feet, the + machine suddenly began to turn up on one wing, and took a course toward + the tree. The operator, not relishing the idea of landing in a thorn tree, + attempted to reach the ground. The left wing, however, struck the tree at + a height of 10 or 12 feet from the ground and carried away several + branches; but the flight, which had already covered a distance of six + miles, was continued to the starting point. + </p> + <p> + 'The causes of these troubles—too technical for explanation here—were + not entirely overcome till the end of September, 1905. The flights then + rapidly increased in length, till experiments were discontinued after + October 5 on account of the number of people attracted to the field. + Although made on a ground open on every side, and bordered on two sides by + much-travelled thoroughfares, with electric cars passing every hour, and + seen by all the people living in the neighbourhood for miles around, and + by several hundred others, yet these flights have been made by some + newspapers the subject of a great "mystery."' + </p> + <p> + Viewing their work from the financial side, the two brothers incurred but + little expense in the earlier gliding experiments, and, indeed, viewed + these only as recreation, limiting their expenditure to that which two men + might spend on any hobby. When they had once achieved successful + power-driven flight, they saw the possibilities of their work, and + abandoned such other business as had engaged their energies, sinking all + their capital in the development of a practical flying machine. Having, in + 1905, improved their designs to such an extent that they could consider + their machine a practical aeroplane, they devoted the years 1906 and 1907 + to business negotiations and to the construction of new machines, resuming + flying experiments in May of 1908 in order to test the ability of their + machine to meet the requirements of a contract they had made with the + United States Government, which required an aeroplane capable of carrying + two men, together with sufficient fuel supplies for a flight of 125 miles + at 40 miles per hour. Practically similar to the machine used in the + experiments of 1905, the contract aeroplane was fitted with a larger + motor, and provision was made for seating a passenger and also for + allowing of the operator assuming a sitting position, instead of lying + prone. + </p> + <p> + Before leaving the work of the brothers to consider contemporary events, + it may be noted that they claimed—with justice—that they were + first to construct wings adjustable to different angles of incidence on + the right and left side in order to control the balance of an aeroplane; + the first to attain lateral balance by adjusting wing-tips to respectively + different angles of incidence on the right and left sides, and the first + to use a vertical vane in combination with wing-tips, adjustable to + respectively different angles of incidence, in balancing and steering an + aeroplane. They were first, too, to use a movable vertical tail, in + combination with wings adjustable to different angles of incidence, in + controlling the balance and direction of an aeroplane.[*] + </p> + <p> + [*]Aeronautical Journal, No. 79. + </p> + <p> + A certain Henry M. Weaver, who went to see the work of the brothers, + writing in a letter which was subsequently read before the Aero Club de + France records that he had a talk in 1905 with the farmer who rented the + field in which the Wrights made their flights.' On October 5th (1905) he + was cutting corn in the next field east, which is higher ground. When he + noticed the aeroplane had started on its flight he remarked to his helper: + "Well, the boys are at it again," and kept on cutting corn, at the same + time keeping an eye on the great white form rushing about its course. "I + just kept on shocking corn," he continued, "until I got down to the fence, + and the durned thing was still going round. I thought it would never + stop."' + </p> + <p> + He was right. The brothers started it, and it will never stop. + </p> + <p> + Mr Weaver also notes briefly the construction of the 1905 Wright flier. + 'The frame was made of larch wood-from tip to tip of the wings the + dimension was 40 feet. The gasoline motor—a special construction + made by them—much the same, though, as the motor on the Pope-Toledo + automobile—was of from 12 to 15 horse-power. The motor weighed 240 + lbs. The frame was covered with ordinary muslin of good quality. No + attempt was made to lighten the machine; they simply built it strong + enough to stand the shocks. The structure stood on skids or runners, like + a sleigh. These held the frame high enough from the ground in alighting to + protect the blades of the propeller. Complete with motor, the machine + weighed 925 lbs. + </p> + <p> + <a name="link2H_4_0014" id="link2H_4_0014"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + XII. THE FIRST YEARS OF CONQUEST + </h2> + <p> + It is no derogation of the work accomplished by the Wright Brothers to say + that they won the honour of the first power-propelled flights in a + heavier-than-air machine only by a short period. In Europe, and especially + in France, independent experiment was being conducted by Ferber, by + Santos-Dumont, and others, while in England Cody was not far behind the + other giants of those days. The history of the early years of controlled + power flights is a tangle of half-records; there were no chroniclers, only + workers, and much of what was done goes unrecorded perforce, since it was + not set down at the time. + </p> + <p> + Before passing to survey of those early years, let it be set down that in + 1907, when the Wright Brothers had proved the practicability of their + machines, negotiations were entered into between the brothers and the + British War office. On April 12th 1907, the apostle of military + stagnation, Haldane, then War Minister, put an end to the negotiations by + declaring that 'the War office is not disposed to enter into relations at + present with any manufacturer of aeroplanes' The state of the British air + service in 1914 at the outbreak of hostilities, is eloquent regarding the + pursuance of the policy which Haldane initiated. + </p> + <p> + 'If I talked a lot,' said Wilbur Wright once, 'I should be like the + parrot, which is the bird that speaks most and flies least.' That attitude + is emblematic of the majority of the early fliers, and because of it the + record of their achievements is incomplete to-day. Ferber, for instance, + has left little from which to state what he did, and that little is + scattered through various periodicals, scrappily enough. A French army + officer, Captain Ferber was experimenting with monoplane and biplane + gliders at the beginning of the century-his work was contemporary with + that of the Wrights. He corresponded both with Chanute and with the + Wrights, and in the end he was commissioned by the French Ministry of War + to undertake the journey to America in order to negotiate with the Wright + Brothers concerning French rights in the patents they had acquired, and to + study their work at first hand. + </p> + <p> + Ferber's experiments in gliding began in 1899 at the Military School at + Fountainebleau, with a canvas glider of some 80 square feet supporting + surface, and weighing 65 lbs. Two years later he constructed a larger and + more satisfactory machine, with which he made numerous excellent glides. + Later, he constructed an apparatus which suspended a plane from a long arm + which swung on a tower, in order that experiments might be carried out + without risk to the experimenter, and it was not until 1905 that he + attempted power-driven free flight. He took up the Voisin design of + biplane for his power-driven flights, and virtually devoted all his + energies to the study of aeronautics. His book, Aviation, its Dawn and + Development, is a work of scientific value—unlike many of his + contemporaries, Ferber brought to the study of the problems of flight a + trained mind, and he was concerned equally with the theoretical problems + of aeronautics and the practical aspects of the subject. + </p> + <p> + After Bleriot's successful cross-Channel flight, it was proposed to offer + a prize of L1,000 for the feat which C. S. Rolls subsequently accomplished + (starting from the English side of the Channel), a flight from Boulogne to + Dover and back; in place of this, however, an aviation week at Boulogne + was organised, but, although numerous aviators were invited to compete, + the condition of the flying grounds was such that no competitions took + place. Ferber was virtually the only one to do any flying at Boulogne, and + at the outset he had his first accident; after what was for those days a + good flight, he made a series of circles with his machine, when it + suddenly struck the ground, being partially wrecked. Repairs were carried + out, and Ferber resumed his exhibition flights, carrying on up to + Wednesday, September 22nd, 1909. On that day he remained in the air for + half an hour, and, as he was about to land, the machine struck a mound of + earth and overturned, pinning Ferber under the weight of the motor. After + being extricated, Ferber seemed to show little concern at the accident, + but in a few minutes he complained of great pain, when he was conveyed to + the ambulance shed on the ground. + </p> + <p> + 'I was foolish,' he told those who were with him there. 'I was flying too + low. It was my own fault and it will be a severe lesson to me. I wanted to + turn round, and was only five metres from the ground.' A little after + this, he got up from the couch on which he had been placed, and almost + immediately collapsed, dying five minutes later. + </p> + <p> + Ferber's chief contemporaries in France were Santos-Dumont, of airship + fame, Henri and Maurice Farman, Hubert Latham, Ernest Archdeacon, and + Delagrange. These are names that come at once to mind, as does that of + Bleriot, who accomplished the second great feat of power-driven flight, + but as a matter of fact the years 1903-10 are filled with a little host of + investigators and experimenters, many of whom, although their names do not + survive to any extent, are but a very little way behind those mentioned + here in enthusiasm and devotion. Archdeacon and Gabriel Voisin, the former + of whom took to heart the success achieved by the Wright Brothers, + co-operated in experiments in gliding. Archdeacon constructed a glider in + box-kite fashion, and Voisin experimented with it on the Seine, the glider + being towed by a motorboat to attain the necessary speed. It was + Archdeacon who offered a cup for the first straight flight of 200 metres, + which was won by Santos-Dumont, and he also combined with Henri Deutsch de + la Meurthe in giving the prize for the first circular flight of a mile, + which was won by Henry Farman on January 13th, 1908. + </p> + <p> + A history of the development of aviation in France in these, the strenuous + years, would fill volumes in itself. Bleriot was carrying out experiments + with a biplane glider on the Seine, and Robert Esnault-Pelterie was + working on the lines of the Wright Brothers, bringing American practice to + France. In America others besides the Wrights had wakened to the + possibilities of heavier-than-air flight; Glenn Curtiss, in company with + Dr Alexander Graham Bell, with J. A. D. McCurdy, and with F. W. Baldwin, a + Canadian engineer, formed the Aerial Experiment Company, which built a + number of aeroplanes, most famous of which were the 'June Bug,' the 'Red + Wing,' and the 'White Wing.' In 1908 the 'June Bug 'won a cup presented by + the Scientific American—it was the first prize offered in America in + connection with aeroplane flight. + </p> + <p> + Among the little group of French experimenters in these first years of + practical flight, Santos-Dumont takes high rank. He built his 'No. 14 bis' + aeroplane in biplane form, with two superposed main plane surfaces, and + fitted it with an eight-cylinder Antoinette motor driving a two-bladed + aluminium propeller, of which the blades were 6 feet only from tip to tip. + The total lift surface of 860 square feet was given with a wing-span of a + little under 40 feet, and the weight of the complete machine was 353 lbs., + of which the engine weighed 158 lbs. In July of 1906 Santos-Dumont flew a + distance of a few yards in this machine, but damaged it in striking the + ground; on October 23rd of the same year he made a flight of nearly 200 + feet—which might have been longer, but that he feared a crowd in + front of the aeroplane and cut off his ignition. This may be regarded as + the first effective flight in Europe, and by it Santos-Dumont takes his + place as one of the chief—if not the chief—of the pioneers of + the first years of practical flight, so far as Europe is concerned. + </p> + <p> + Meanwhile, the Voisin Brothers, who in 1904 made cellular kites for + Archdeacon to test by towing on the Seine from a motor launch, obtained + data for the construction of the aeroplane which Delagrange and Henry + Farman were to use later. The Voisin was a biplane, constructed with due + regard to the designs of Langley, Lilienthal, and other earlier + experimenters—both the Voisins and M. Colliex, their engineer, + studied Lilienthal pretty exhaustively in getting out their design, though + their own researches were very thorough as well. The weight of this Voisin + biplane was about 1,450 lbs., and its maximum speed was some 38 to 40 + miles per hour, the total supporting surface being about 535 square feet. + It differed from the Wright design in the possession of a tail-piece, a + characteristic which marked all the French school of early design as in + opposition to the American. The Wright machine got its longitudinal + stability by means of the main planes and the elevating planes, while the + Voisin type added a third factor of stability in its sailplanes. Further, + the Voisins fitted their biplane with a wheeled undercarriage, while the + Wright machine, being fitted only with runners, demanded a launching rail + for starting. Whether a machine should be tailless or tailed was for some + long time matter for acute controversy, which in the end was settled by + the fitting of a tail to the Wright machines-France won the dispute by the + concession. + </p> + <p> + Henry Farman, who began his flying career with a Voisin machine, evolved + from it the aeroplane which bore his name, following the main lines of the + Voisin type fairly closely, but making alterations in the controls, and in + the design of the undercarriage, which was somewhat elaborated, even to + the inclusion of shock absorbers. The seven-cylinder 50 horse-power Gnome + rotary engine was fitted to the Farman machine—the Voisins had + fitted an eight-cylinder Antoinette, giving 50 horse-power at 1,100 + revolutions per minute, with direct drive to the propeller. Farman reduced + the weight of the machine from the 1,450 lbs. of the Voisins to some 1,010 + lbs. or thereabouts, and the supporting area to 450 square feet. This + machine won its chief fame with Paulhan as pilot in the famous London to + Manchester flight—it is to be remarked, too, that Farman himself was + the first man in Europe to accomplish a flight of a mile. + </p> + <p> + Other notable designs of these early days were the 'R.E.P.', Esnault + Pelterie's machine, and the Curtiss-Herring biplane. Of these Esnault + Pelterie's was a monoplane, designed in that form since Esnault Pelterie + had found by experiment that the wire used in bracing offers far more + resistance to the air than its dimensions would seem to warrant. He built + the wings of sufficient strength to stand the strain of flight without + bracing wires, and dependent only for their support on the points of + attachment to the body of the machine; for the rest, it carried its + propeller in front of the planes, and both horizontal and vertical rudders + at the stern—a distinct departure from the Wright and similar types. + One wheel only was fixed under the body where the undercarriage exists on + a normal design, but light wheels were fixed, one at the extremity of each + wing, and there was also a wheel under the tail portion of the machine. A + single lever actuated all the controls for steering. With a supporting + surface of 150 square feet the machine weighed 946 lbs., about 6.4 lbs. + per square foot of lifting surface. + </p> + <p> + The Curtiss biplane, as flown by Glenn Curtiss at the Rheims meeting, was + built with a bamboo framework, stayed by means of very fine steel-stranded + cables. A—then—novel feature of the machine was the moving of + the ailerons by the pilot leaning to one side or the other in his seat, a + light, tubular arm-rest being pressed by his body when he leaned to one + side or the other, and thus operating the movement of the ailerons + employed for tilting the plane when turning. A steering-wheel fitted + immediately in front of the pilot's seat served to operate a rear + steering-rudder when the wheel was turned in either direction, while + pulling back the wheel altered the inclination of the front elevating + planes, and so gave lifting or depressing control of the plane. + </p> + <p> + This machine ran on three wheels before leaving the ground, a central + undercarriage wheel being fitted in front, with two more in line with a + right angle line drawn through the centre of the engine crank at the rear + end of the crank-case. The engine was a 35 horsepower Vee design, water + cooled, with overhead inlet and exhaust valves, and Bosch high-tension + magneto ignition. The total weight of the plane in flying order was about + 700 lbs. + </p> + <p> + As great a figure in the early days as either Ferber or Santos-Dumont was + Louis Bleriot, who, as early as 1900 built a flapping-wing model, this + before ever he came to experimenting with the Voisin biplane type of + glider on the Seine. Up to 1906 he had built four biplanes of his own + design, and in March of 1907 he built his first monoplane, to wreck it + only a few days after completion in an accident from which he had a + fortunate escape. His next machine was a double monoplane, designed after + Langley's precept, to a certain extent, and this was totally wrecked in + September of 1907. His seventh machine, a monoplane, was built within a + month of this accident, and with this he had a number of mishaps, also + achieving some good flights, including one in which he made a turn. It was + wrecked in December of 1907, whereupon he built another monoplane on + which, on July 6th, 1908, Bleriot made a flight lasting eight and a half + minutes. In October of that year he flew the machine from Toury to Artenay + and returned on it—this was just a day after Farman's first + cross-country flight—but, trying to repeat the success five days + later, Bleriot collided with a tree in a fog and wrecked the machine past + repair. Thereupon he set about building his eleventh machine, with which + he was to achieve the first flight across the English channel. + </p> + <p> + Henry Farman, to whom reference has already been made, was engaged with + his two brothers, Maurice and Richard, in the motor-car business, and + turned to active interest in flying in 1907, when the Voisin firm built + his first biplane on the box-kite principle. In July of 1908 he won a + prize of L400 for a flight of thirteen miles, previously having completed + the first kilometre flown in Europe with a passenger, the said passenger + being Ernest Archdeaon. In September of 1908 Farman put up a speed record + of forty miles an hour in a flight lasting forty minutes. + </p> + <p> + Santos-Dumont produced the famous 'Demoiselle' monoplane early in 1909, a + tiny machine in which the pilot had his seat in a sort of miniature cage + under the main plane. It was a very fast, light little machine but was + difficult to fly, and owing to its small wingspread was unable to glide at + a reasonably safe angle. There has probably never been a cheaper flying + machine to build than the 'Demoiselle,' which could be so upset as to seem + completely wrecked, and then repaired ready for further flight by a couple + of hours' work. Santos-Dumont retained no patent in the design, but gave + it out freely to any one who chose to build 'Demoiselles'; the vogue of + the pattern was brief, owing to the difficulty of piloting the machine. + </p> + <p> + These were the years of records, broken almost as soon as made. There was + Farman's mile, there was the flight of the Comte de Lambert over the + Eiffel Tower, Latham's flight at Blackpool in a high wind, the Rheims + records, and then Henry Farman's flight of four hours later in 1909, + Orville Wright's height record of 1,640 feet, and Delagrange's speed + record of 49.9 miles per hour. The coming to fame of the Gnome rotary + engine helped in the making of these records to a very great extent, for + in this engine was a prime mover which gave the reliability that aeroplane + builders and pilots had been searching for, but vainly. The Wrights and + Glenn Curtiss, of course, had their own designs of engine, but the Gnome, + in spite of its lack of economy in fuel and oil, and its high cost, soon + came to be regarded as the best power plant for flight. + </p> + <p> + Delagrange, one of the very good pilots of the early days, provided a + curious insight to the way in which flying was regarded, at the opening of + the Juvisy aero aerodrome in May of 1909. A huge crowd had gathered for + the first day's flying, and nine machines were announced to appear, but + only three were brought out. Delagrange made what was considered an + indifferent little flight, and another pilot, one De Bischoff, attempted + to rise, but could not get his machine off the ground. Thereupon the crowd + of 30,000 people lost their tempers, broke down the barriers surrounding + the flying course, and hissed the officials, who were quite unable to + maintain order. Delagrange, however, saved the situation by making a + circuit of the course at a height of thirty feet from the ground, which + won him rounds of cheering and restored the crowd to good humour. Possibly + the smash achieved by Rougier, the famous racing motorist, who crashed his + Voisin biplane after Delagrange had made his circuit, completed the + enjoyment of the spectators. Delagrange, flying at Argentan in June of + 1909, made a flight of four kilometres at a height of sixty feet; for + those days this was a noteworthy performance. Contemporary with this was + Hubert Latham's flight of an hour and seven minutes on an Antoinette + monoplane; this won the adjective 'magnificent' from contemporary + recorders of aviation. + </p> + <p> + Viewing the work of the little group of French experimenters, it is, at + this length of time from their exploits, difficult to see why they carried + the art as far as they did. There was in it little of satisfaction, a + certain measure of fame, and practically no profit—the giants of + those days got very little for their pains. Delagrange's experience at the + opening of the Juvisy ground was symptomatic of the way in which flight + was regarded by the great mass of people—it was a sport, and nothing + more, but a sport without the dividends attaching to professional football + or horse-racing. For a brief period, after the Rheims meeting, there was a + golden harvest to be reaped by the best of the pilots. Henry Farman asked + L2,000 for a week's exhibition flying in England, and Paulhan asked half + that sum, but a rapid increase in the number of capable pilots, together + with the fact that most flying meetings were financial failures, owing to + great expense in organisation and the doubtful factor of the weather, + killed this goose before many golden eggs had been gathered in by the star + aviators. Besides, as height and distance records were broken one after + another, it became less and less necessary to pay for entrance to an + aerodrome in order to see a flight—the thing grew too big for a mere + sports ground. + </p> + <p> + Long before Rheims and the meeting there, aviation had grown too big for + the chronicling of every individual effort. In that period of the first + days of conquest of the air, so much was done by so many whose names are + now half-forgotten that it is possible only to pick out the great figures + and make brief reference to their achievements and the machines with which + they accomplished so much, pausing to note such epoch-making events as the + London-Manchester flight, Bleriot's Channel crossing, and the Rheims + meeting itself, and then passing on beyond the days of individual records + to the time when the machine began to dominate the man. This latter + because, in the early days, it was heroism to trust life to the planes + that were turned out—the 'Demoiselle' and the Antoinette machine + that Latham used in his attempt to fly the Channel are good examples of + the flimsiness of early types—while in the later period, that of the + war and subsequently, the heroism turned itself in a different—and + nobler-direction. Design became standardised, though not perfected. The + domination of the machine may best be expressed by contrasting the way in + which machines came to be regarded as compared with the men who flew them: + up to 1909, flying enthusiasts talked of Farman, of Bleriot, of Paulhan, + Curtiss, and of other men; later, they began to talk of the Voisin, the + Deperdussin, and even to the Fokker, the Avro, and the Bristol type. With + the standardising of the machine, the days of the giants came to an end. + </p> + <p> + <a name="link2H_4_0015" id="link2H_4_0015"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + XIII. FIRST FLIERS IN ENGLAND + </h2> + <p> + Certain experiments made in England by Mr Phillips seem to have come near + robbing the Wright Brothers of the honour of the first flight; notes made + by Colonel J. D. Fullerton on the Phillips flying machine show that in + 1893 the first machine was built with a length of 25 feet, breadth of 22 + feet, and height of 11 feet, the total weight, including a 72 lb. load, + being 420 lbs. The machine was fitted with some fifty wood slats, in place + of the single supporting surface of the monoplane or two superposed + surfaces of the biplane, these slats being fixed in a steel frame so that + the whole machine rather resembled a Venetian blind. A steam engine giving + about 9 horse-power provided the motive power for the six-foot diameter + propeller which drove the machine. As it was not possible to put a + passenger in control as pilot, the machine was attached to a central post + by wire guys and run round a circle 100 feet in diameter, the track + consisting of wooden planking 4 feet wide. Pressure of air under the slats + caused the machine to rise some two or three feet above the track when + sufficient velocity had been attained, and the best trials were made on + June 19th 1893, when at a speed of 40 miles an hour, with a total load of + 385 lbs., all the wheels were off the ground for a distance of 2,000 feet. + </p> + <p> + In 1904 a full-sized machine was constructed by Mr Phillips, with a total + weight, including that of the pilot, of 600 lbs. The machine was designed + to lift when it had attained a velocity of 50 feet per second, the motor + fitted giving 22 horse-power. On trial, however, the longitudinal + equilibrium was found to be defective, and a further design was got out, + the third machine being completed in 1907. In this the wood slats were + held in four parallel container frames, the weight of the machine, + excluding the pilot, being 500 lbs. A motor similar to that used in the + 1904 machine was fitted, and the machine was designed to lift at a + velocity of about 30 miles an hour, a seven-foot propeller doing the + driving. Mr Phillips tried out this machine in a field about 400 yards + across. 'The machine was started close to the hedge, and rose from the + ground when about 200 yards had been covered. When the machine touched the + ground again, about which there could be no doubt, owing to the terrific + jolting, it did not run many yards. When it came to rest I was about ten + yards from the boundary. Of course, I stopped the engine before I + commenced to descend.'[*] + </p> + <p> + [*] Aeronautical Journal, July, 1908. + </p> + <p> + S. F. Cody, an American by birth, aroused the attention not only of the + British public, but of the War office and Admiralty as well, as early as + 1905 with his man-lifting kites. In that year a height of 1,600 feet was + reached by one of these box-kites, carrying a man, and later in the same + year one Sapper Moreton, of the Balloon Section of the Royal Engineers + (the parent of the Royal Flying Corps) remained for an hour at an altitude + of 2,600 feet. Following on the success of these kites, Cody constructed + an aeroplane which he designated a 'power kite,' which was in reality a + biplane that made the first flight in Great Britain. Speaking before the + Aeronautical Society in 1908, Cody said that 'I have accomplished one + thing that I hoped for very much, that is, to be the first man to fly in + Great Britain.... I made a machine that left the ground the first time + out; not high, possibly five or six inches only. I might have gone higher + if I wished. I made some five flights in all, and the last flight came to + grief.... On the morning of the accident I went out after adjusting my + propellers at 8 feet pitch running at 600 (revolutions per minute). I + think that I flew at about twenty-eight miles per hour. I had 50 + horsepower motor power in the engine. A bunch of trees, a flat common + above these trees, and from this flat there is a slope goes down... to + another clump of trees. Now, these clumps of trees are a quarter of a mile + apart or thereabouts.... I was accused of doing nothing but jumping with + my machine, so I got a bit agitated and went to fly. + </p> + <p> + I went out this morning with an easterly wind, and left the ground at the + bottom of the hill and struck the ground at the top, a distance of 74 + yards. That proved beyond a doubt that the machine would fly—it flew + uphill. That was the most talented flight the machine did, in my opinion. + Now, I turned round at the top and started the machine and left the ground—remember, + a ten mile wind was blowing at the time. Then, 60 yards from where the men + let go, the machine went off in this direction (demonstrating)—I + make a line now where I hoped to land—to cut these trees off at that + side and land right off in here. I got here somewhat excited, and started + down and saw these trees right in front of me. I did not want to smash my + head rudder to pieces, so I raised it again and went up. I got one wing + direct over that clump of trees, the right wing over the trees, the left + wing free; the wind, blowing with me, had to lift over these trees. So I + consequently got a false lift on the right side and no lift on the left + side. Being only about 8 feet from the tree tops, that turned my machine + up like that (demonstrating). This end struck the ground shortly after I + had passed the trees. I pulled the steering handle over as far as I could. + Then I faced another bunch of trees right in front of me. Trying to avoid + this second bunch of trees I turned the rudder, and turned it rather + sharp. That side of the machine struck, and it crumpled up like so much + tissue paper, and the machine spun round and struck the ground that way + on, and the framework was considerably wrecked. Now, I want to advise all + aviators not to try to fly with the wind and to cross over any big clump + of earth or any obstacle of any description unless they go square over the + top of it, because the lift is enormous crossing over anything like that, + and in coming the other way against the wind it would be the same thing + when you arrive at the windward side of the obstacle. That is a point I + did not think of, and had I thought of it I would have been more + cautious.' + </p> + <p> + This Cody machine was a biplane with about 40 foot span, the wings being + about 7 feet in depth with about 8 feet between upper and lower wing + surfaces. 'Attached to the extremities of the lower planes are two small + horizontal planes or rudders, while a third small vertical plane is fixed + over the centre of the upper plane.' The tail-piece and principal rudder + were fitted behind the main body of the machine, and a horizontal rudder + plane was rigged out in front, on two supporting arms extending from the + centre of the machine. The small end-planes and the vertical plane were + used in conjunction with the main rudder when turning to right or left, + the inner plane being depressed on the turn, and the outer one + correspondingly raised, while the vertical plane, working in conjunction, + assisted in preserving stability. Two two-bladed propellers were driven by + an eight-cylinder 50 horse-power Antoinette motor. With this machine Cody + made his first flights over Laffan's plain, being then definitely attached + to the Balloon Section of the Royal Engineers as military aviation + specialist. + </p> + <p> + There were many months of experiment and trial, after the accident which + Cody detailed in the statement given above, and then, on May 14th, 1909, + Cody took the air and made a flight of 1,200 yards with entire success. + Meanwhile A. V. Roe was experimenting at Lea Marshes with a triplane of + rather curious design the pilot having his seat between two sets of three + superposed planes, of which the front planes could be tilted and twisted + while the machine was in motion. He comes but a little way after Cody in + the chronology of early British experimenters, but Cody, a born inventor, + must be regarded as the pioneer of the present century so far as Britain + is concerned. He was neither engineer nor trained mathematician, but he + was a good rule-of-thumb mechanic and a man of pluck and perseverance; he + never strove to fly on an imperfect machine, but made alteration after + alteration in order to find out what was improvement and what was not, in + consequence of which it was said of him that he was 'always satisfied with + his alterations.' + </p> + <p> + By July of 1909 he had fitted an 80 horse-power motor to his biplane, and + with this he made a flight of over four miles over Laffan's Plain on July + 21st. By August he was carrying passengers, the first being Colonel Capper + of the R.E. Balloon Section, who flew with Cody for over two miles, and on + September 8th, 1909, he made a world's record cross-country flight of over + forty miles in sixty-six minutes, taking a course from Laffan's Plain over + Farnborough, Rushmoor, and Fleet, and back to Laffan's Plain. He was one + of the competitors in the 1909 Doncaster Aviation Meeting, and in 1910 he + competed at Wolverhampton, Bournemouth, and Lanark. It was on June 7th, + 1910, that he qualified for his brevet, No. 9, on the Cody biplane. + </p> + <p> + He built a machine which embodied all the improvements for which he had + gained experience, in 1911, a biplane with a length of 35 feet and span of + 43 feet, known as the 'Cody cathedral' on account of its rather cumbrous + appearance. With this, in 1911, he won the two Michelin trophies presented + in England, completed the Daily Mail circuit of Britain, won the Michelin + cross-country prize in 1912 and altogether, by the end of 1912, had + covered more than 7,000 miles with the machine. It was fitted with a 120 + horse-power Austro-Daimler engine, and was characterised by an + exceptionally wide range of speed—the great wingspread gave a slow + landing speed. + </p> + <p> + A few of his records may be given: in 1910, flying at Laffan's Plain in + his biplane, fitted with a 50-60 horsepower Green engine, on December + 31st, he broke the records for distance and time by flying 185 miles, 787 + yards, in 4 hours 37 minutes. On October 31st, 1911, he beat this record + by flying for 5 hours 15 minutes, in which period he covered 261 miles 810 + yards with a 60 horse-power Green engine fitted to his biplane. In 1912, + competing in the British War office tests of military aeroplanes, he won + the L5,000 offered by the War Office. This was in competition with no less + than twenty-five other machines, among which were the since-famous + Deperdussin, Bristol, Flanders, and Avro types, as well as the Maurice + Farman and Bleriot makes of machine. Cody's remarkable speed range was + demonstrated in these trials, the speeds of his machine varying between + 72.4 and 48.5 miles per hour. The machine was the only one delivered for + the trials by air, and during the three hours' test imposed on all + competitors a maximum height of 5,000 feet was reached, the first thousand + feet being achieved in three and a half minutes. + </p> + <p> + During the summer of 1913 Cody put his energies into the production of a + large hydro-biplane, with which he intended to win the L5,000 prize + offered by the Daily Mail to the first aviator to fly round Britain on a + waterplane. This machine was fitted with landing gear for its tests, and, + while flying it over Laffan's Plain on August 7th, 1913, with Mr W. H. B. + Evans as passenger, Cody met with the accident that cost both him and his + passenger their lives. Aviation lost a great figure by his death, for his + plodding, experimenting, and dogged courage not only won him the fame that + came to a few of the pilots of those days, but also advanced the cause of + flying very considerably and contributed not a little to the sum of + knowledge in regard to design and construction. + </p> + <p> + Another figure of the early days was A. V. Roe, who came from marine + engineering to the motor industry and aviation in 1905. In 1906 he went + out to Colorado, getting out drawings for the Davidson helicopter, and in + 1907 having returned to England, he obtained highest award out of 200 + entries in a model aeroplane flying competition. From the design of this + model he built a full-sized machine, and made a first flight on it, fitted + with a 24 horse-power Antoinette engine, in June of 1908 Later, he fitted + a 9 horsepower motor-cycle engine to a triplane of his own design, and + with this made a number of short flights; he got his flying brevet on a + triplane with a motor of 35 horse-power, which, together with a second + triplane, was entered for the Blackpool aviation meeting of 1910 but was + burnt in transport to the meeting. He was responsible for the building of + the first seaplane to rise from English waters, and may be counted the + pioneer of the tractor type of biplane. In 1913 he built a two-seater + tractor biplane with 80 horse-power engine, a machine which for some + considerable time ranked as a leader of design. Together with E. V. Roe + and H. V. Roe, 'A. V.' controlled the Avro works, which produced some of + the most famous training machines of the war period in a modification of + the original 80 horse-power tractor. The first of the series of Avro + tractors to be adopted by the military authorities was the 1912 biplane, a + two-seater fitted with 50 horsepower engine. It was the first tractor + biplane with a closed fuselage to be used for military work, and became + standard for the type. The Avro seaplane, of I 100 horse-power (a + fourteen-cylinder Gnome engine was used) was taken up by the British + Admiralty in 1913. It had a length of 34 feet and a wing-span of 50 feet, + and was of the twin-float type. + </p> + <p> + Geoffrey de Havilland, though of later rank, counts high among designers + of British machines. He qualified for his brevet as late as February, + 1911, on a biplane of his own construction, and became responsible for the + design of the BE2, the first successful British Government biplane. On + this he made a British height record of 10,500 feet over Salisbury Plain, + in August of 1912, when he took up Major Sykes as passenger. In the war + period he was one of the principal designers of fighting and + reconnaissance machines. + </p> + <p> + F. Handley Page, who started in business as an aeroplane builder in 1908, + having works at Barking, was one of the principal exponents of the + inherently stable machine, to which he devoted practically all his + experimental work up to the outbreak of war. The experiments were made + with various machines, both of monoplane and biplane type, and of these + one of the best was a two-seater monoplane built in 1911, while a second + was a larger machine, a biplane, built in 1913 and fitted with a 110 + horse-power Anzani engine. The war period brought out the giant biplane + with which the name of Handley Page is most associated, the twin-engined + night-bomber being a familiar feature of the later days of the war; the + four-engined bomber had hardly had a chance of proving itself under + service conditions when the war came to an end. + </p> + <p> + Another notable figure of the early period was 'Tommy' Sopwith, who took + his flying brevet at Brooklands in November of 1910, and within four days + made the British duration record of 108 miles in 3 hours 12 minutes. On + December 18th, 1910, he won the Baron de Forrest prize of L4,000 for the + longest flight from England to the Continent, flying from Eastchurch to + Tirlemont, Belgium, in three hours, a distance of 161 miles. After two + years of touring in America, he returned to England and established a + flying school. In 1912 he won the first aerial Derby, and in 1913 a + machine of his design, a tractor biplane, raised the British height record + to 13,000 feet (June 16th, at Brooklands). First as aviator, and then as + designer, Sopwith has done much useful work in aviation. + </p> + <p> + These are but a few, out of a host who contributed to the development of + flying in this country, for, although France may be said to have set the + pace as regards development, Britain was not far behind. French + experimenters received far more Government aid than did the early British + aviators and designers—in the early days the two were practically + synonymous, and there are many stories of the very early days at + Brooklands, where, when funds ran low, the ardent spirits patched their + trousers with aeroplane fabric and went on with their work with Bohemian + cheeriness. Cody, altering and experimenting on Laffan's Plain, is the + greatest figure of them all, but others rank, too, as giants of the early + days, before the war brought full recognition of the aeroplane's + potentialities. + </p> + <p> + One of the first men actually to fly in England, Mr J. C. T. + Moore-Brabazon, was a famous figure in the days of exhibition flying, and + won his reputation mainly through being first to fly a circular mile on a + machine designed and built in Great Britain and piloted by a British + subject. Moore-Brabazon's earliest flights were made in France on a Voisin + biplane in 1908, and he brought this machine over to England, to the Aero + Club grounds at Shellness, but soon decided that he would pilot a British + machine instead. An order was placed for a Short machine, and this, fitted + with a 50-60 horse-power Green engine, was used for the circular mile, + which won a prize of L1,000 offered by the Daily Mail, the feat being + accomplished on October 30th, 1909. Five days later, Moore-Brabazon + achieved the longest flight up to that time accomplished on a + British-built machine, covering three and a half miles. In connection with + early flying in England, it is claimed that A. V. Roe, flying 'Avro B,',' + on June 8th, 1908, was actually the first man to leave the ground, this + being at Brooklands, but in point of fact Cody antedated him. + </p> + <p> + No record of early British fliers could be made without the name of C. S. + Rolls, a son of Lord Llangattock, on June 2nd, 1910, he flew across the + English Channel to France, until he was duly observed over French + territory, when he returned to England without alighting. The trip was + made on a Wright biplane, and was the third Channel crossing by air, + Bleriot having made the first, and Jacques de Lesseps the second. Rolls + was first to make the return journey in one trip. He was eventually killed + through the breaking of the tail-plane of his machine in descending at a + flying meeting at Bournemouth. The machine was a Wright biplane, but the + design of the tail-plane—which, by the way, was an addition to the + machine, and was not even sanctioned by the Wrights—appears to have + been carelessly executed, and the plane itself was faulty in construction. + The breakage caused the machine to overturn, killing Rolls, who was + piloting it. + </p> + <p> + <a name="link2H_4_0016" id="link2H_4_0016"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + XIV. RHEIMS, AND AFTER + </h2> + <p> + The foregoing brief—and necessarily incomplete—survey of the + early British group of fliers has taken us far beyond some of the great + events of the early days of successful flight, and it is necessary to go + back to certain landmarks in the history of aviation, first of which is + the great meeting at Rheims in 1909. Wilbur Wright had come to Europe, + and, flying at Le Mans and Pau—it was on August 8th, 1908, that + Wilbur Wright made the first of his ascents in Europe—had stimulated + public interest in flying in France to a very great degree. Meanwhile, + Orville Wright, flying at Fort Meyer, U.S.A., with Lieutenant Selfridge as + a passenger, sustained an accident which very nearly cost him his life + through the transmission gear of the motor breaking. Selfridge was killed + and Orville Wright was severely injured—it was the first fatal + accident with a Wright machine. + </p> + <p> + Orville Wright made a flight of over an hour on September 9th, 1908, and + on December 31st of that year Wilbur flew for 2 hours 19 minutes. Thus, + when the Rheims meeting was organised—more notable because it was + the first of its kind, there were already records waiting to be broken. + The great week opened on August 22nd, there being thirty entrants, + including all the most famous men among the early fliers in France. + Bleriot, fresh from his Channel conquest, was there, together with Henry + Farman, Paulhan, Curtiss, Latham, and the Comte de Lambert, first pupil of + the Wright machine in Europe to achieve a reputation as an aviator. + </p> + <p> + 'To say that this week marks an epoch in the history of the world is to + state a platitude. Nevertheless, it is worth stating, and for us who are + lucky enough to be at Rheims during this week there is a solid + satisfaction in the idea that we are present at the making of history. In + perhaps only a few years to come the competitions of this week may look + pathetically small and the distances and speeds may appear paltry. + Nevertheless, they are the first of their kind, and that is sufficient.' + </p> + <p> + So wrote a newspaper correspondent who was present at the famous meeting, + and his words may stand, being more than mere journalism; for the great + flying week which opened on August 22nd, 1909, ranks as one of the great + landmarks in the history of heavier-than-air flight. The day before the + opening of the meeting a downpour of rain spoilt the flying ground; Sunday + opened with a fairly high wind, and in a lull M. Guffroy turned out on a + crimson R.E.P. monoplane, but the wheels of his undercarriage stuck in the + mud and prevented him from rising in the quarter of an hour allowed to + competitors to get off the ground. Bleriot, following, succeeded in + covering one side of the triangular course, but then came down through + grit in the carburettor. Latham, following him with thirteen as the number + of his machine, experienced his usual bad luck and came to earth through + engine trouble after a very short flight. Captain Ferber, who, owing to + military regulations, always flew under the name of De Rue, came out next + with his Voisin biplane, but failed to get off the ground; he was followed + by Lefebvre on a Wright biplane, who achieved the success of the morning + by rounding the course—a distance of six and a quarter miles—in + nine minutes with a twenty mile an hour wind blowing. His flight finished + the morning. + </p> + <p> + Wind and rain kept competitors out of the air until the evening, when + Latham went up, to be followed almost immediately by the Comte de Lambert. + Sommer, Cockburn (the only English competitor), Delagrange, Fournier, + Lefebvre, Bleriot, Bunau-Varilla, Tissandier, Paulhan, and Ferber turned + out after the first two, and the excitement of the spectators at seeing so + many machines in the air at one time provoked wild cheering. The only + accident of the day came when Bleriot damaged his propeller in colliding + with a haycock. + </p> + <p> + The main results of the day were that the Comte de Lambert flew 30 + kilometres in 29 minutes 2 seconds; Lefebvre made the ten-kilometre circle + of the track in just a second under 9 minutes, while Tissandier did it in + 9 1/4 minutes, and Paulhan reached a height of 230 feet. Small as these + results seem to us now, and ridiculous as may seem enthusiasm at the sight + of a few machines in the air at the same time, the Rheims Meeting remains + a great event, since it proved definitely to the whole world that the + conquest of the air had been achieved. + </p> + <p> + Throughout the week record after record was made and broken. Thus on the + Monday, Lefebvre put up a record for rounding the course and Bleriot beat + it, to be beaten in turn by Glenn Curtiss on his Curtiss-Herring biplane. + On that day, too, Paulhan covered 34 3/4 miles in 1 hour 6 minutes. On the + next day, Paulhan on his Voisin biplane took the air with Latham, and + Fournier followed, only to smash up his machine by striking an eddy of + wind which turned him over several times. On the Thursday, one of the + chief events was Latham's 43 miles accomplished in 1 hour 2 minutes in the + morning and his 96.5 miles in 2 hours 13 minutes in the afternoon, the + latter flight only terminated by running out of petrol. On the Friday, the + Colonel Renard French airship, which had flown over the ground under the + pilotage of M. Kapfarer, paid Rheims a second visit; Latham manoeuvred + round the airship on his Antoinette and finally left it far behind. Henry + Farman won the Grand Prix de Champagne on this day, covering 112 miles in + 3 hours, 4 minutes, 56 seconds, Latham being second with his 96.5 miles + flight, and Paulhan third. + </p> + <p> + On the Saturday, Glenn Curtiss came to his own, winning the Gordon-Bennett + Cup by covering 20 kilometres in 15 minutes 50.6 seconds. Bleriot made a + good second with 15 minutes 56.2 seconds as his time, and Latham and + Lefebvre were third and fourth. Farman carried off the passenger prize by + carrying two passengers a distance of 6 miles in 10 minutes 39 seconds. On + the last day Delagrange narrowly escaped serious accident through the + bursting of his propeller while in the air, Curtiss made a new speed + record by travelling at the rate of over 50 miles an hour, and Latham, + rising to 500 feet, won the altitude prize. + </p> + <p> + These are the cold statistics of the meeting; at this length of time it is + difficult to convey any idea of the enthusiasm of the crowds over the + achievements of the various competitors, while the incidents of the week, + comic and otherwise, are nearly forgotten now even by those present in + this making of history. Latham's great flight on the Thursday was rendered + a breathless episode by a downpour of rain when he had covered all but a + kilometre of the record distance previously achieved by Paulhan, and there + was wild enthusiasm when Latham flew on through the rain until he had put + up a new record and his petrol had run out. Again, on the Friday + afternoon, the Colonel Renard took the air together with a little French + dirigible, Zodiac III; Latham was already in the air directly over Farman, + who was also flying, and three crows which turned out as rivals to the + human aviators received as much cheering for their appearance as had been + accorded to the machines, which doubtless they could not understand. + Frightened by the cheering, the crows tried to escape from the course, but + as they came near the stands, the crowd rose to cheer again and the crows + wheeled away to make a second charge towards safety, with the same result; + the crowd rose and cheered at them a third and fourth time; between ten + and fifteen thousand people stood on chairs and tables and waved hats and + handkerchiefs at three ordinary, everyday crows. One thoughtful spectator, + having thoroughly enjoyed the funny side of the incident, remarked that + the ultimate mastery of the air lies with the machine that comes nearest + to natural flight. This still remains for the future to settle. + </p> + <p> + Farman's world record, which won the Grand Prix de Champagne, was done + with a Gnome Rotary Motor which had only been run on the test bench and + was fitted to his machine four hours before he started on the great + flight. His propeller had never been tested, having only been completed + the night before. The closing laps of that flight, extending as they did + into the growing of the dusk, made a breathlessly eerie experience for + such of the spectators as stayed on to watch—and these were many. + Night came on steadily and Farman covered lap after lap just as steadily, + a buzzing, circling mechanism with something relentless in its isolated + persistency. + </p> + <p> + The final day of the meeting provided a further record in the quarter + million spectators who turned up to witness the close of the great week. + Bleriot, turning out in the morning, made a landing in some such fashion + as flooded the carburettor and caused it to catch fire. Bleriot himself + was badly burned, since the petrol tank burst and, in the end, only the + metal parts of the machine were left. Glenn Curtis tried to beat Bleriot's + time for a lap of the course, but failed. In the evening, Farman and + Latham went out and up in great circles, Farman cleaving his way upward in + what at the time counted for a huge machine, on circles of about a mile + diameter. His first round took him level with the top of the stands, and, + in his second, he circled the captive balloon anchored in the middle of + the grounds. After another circle, he came down on a long glide, when + Latham's lean Antoinette monoplane went up in circles more graceful than + those of Farman. 'Swiftly it rose and swept round close to the balloon, + veered round to the hangars, and out over to the Rheims road. Back it came + high over the stands, the people craning their necks as the shrill cry of + the engine drew nearer and nearer behind the stands. Then of a sudden, the + little form appeared away up in the deep twilight blue vault of the sky, + heading straight as an arrow for the anchored balloon. Over it, and high, + high above it went the Antoinette, seemingly higher by many feet than the + Farman machine. Then, wheeling in a long sweep to the left, Latham steered + his machine round past the stands, where the people, their nerve-tension + released on seeing the machine descending from its perilous height of 500 + feet, shouted their frenzied acclamations to the hero of the meeting. + </p> + <p> + 'For certainly "Le Tham," as the French call him, was the popular hero. He + always flew high, he always flew well, and his machine was a joy to the + eye, either afar off or at close quarters. The public feeling for Bleriot + is different. Bleriot, in the popular estimation, is the man who fights + against odds, who meets the adverse fates calmly and with good courage, + and to whom good luck comes once in a while as a reward for much labour + and anguish, bodily and mental. Latham is the darling of the Gods, to whom + Fate has only been unkind in the matter of the Channel flight, and only + then because the honour belonged to Bleriot. + </p> + <p> + 'Next to these two, the public loved most Lefebvre, the joyous, the + gymnastic. Lefebvre was the comedian of the meeting. When things began to + flag, the gay little Lefebvre would trot out to his starting rail, out at + the back of the judge's enclosure opposite the stands, and after a little + twisting of propellers his Wright machine would bounce off the end of its + starting rail and proceed to do the most marvellous tricks for the benefit + of the crowd, wheeling to right and left, darting up and down, now flying + over a troop of the cavalry who kept the plain clear of people and sending + their horses into hysterics, anon making straight for an unfortunate + photographer who would throw himself and his precious camera flat on the + ground to escape annihilation as Lefebvre swept over him 6 or 7 feet off + the ground. Lefebvre was great fun, and when he had once found that his + machine was not fast enough to compete for speed with the Bleriots, + Antoinettes, and Curtiss, he kept to his metier of amusing people. The + promoters of the meeting owe Lefebvre a debt of gratitude, for he provided + just the necessary comic relief.'—(The Aero, September 7th, 1909.) + </p> + <p> + It may be noted, in connection with the fact that Cockburn was the only + English competitor at the meeting, that the Rheims Meeting did more than + anything which had preceded it to waken British interest in aviation. + Previously, heavier-than-air flight in England had been regarded as a + freak business by the great majority, and the very few pioneers who + persevered toward winning England a share in the conquest of the air came + in for as much derision as acclamation. Rheims altered this; it taught the + world in general, and England in particular, that a serious rival to the + dirigible balloon had come to being, and it awakened the thinking portion + of the British public to the fact that the aeroplane had a future. + </p> + <p> + The success of this great meeting brought about a host of imitations of + which only a few deserve bare mention since, unlike the first, they taught + nothing and achieved little. There was the meeting at Boulogne late in + September of 1909, of which the only noteworthy event was Ferber's death. + There was a meeting at Brescia where Curtiss again took first prize for + speed and Rougier put up a world's height record of 645 feet. The + Blackpool meeting followed between 18th and 23rd of October, 1909, + forming, with the exception of Doncaster, the first British Flying + Meeting. Chief among the competitors were Henry Farman, who took the + distance prize, Rougier, Paulhan, and Latham, who, by a flight in a high + wind, convinced the British public that the theory that flying was only + possible in a calm was a fallacy. A meeting at Doncaster was practically + simultaneous with the Blackpool week; Delagrange, Le Blon, Sommer, and + Cody were the principal figures in this event. It should be added that 130 + miles was recorded as the total flown at Doncaster, while at Blackpool + only 115 miles were flown. Then there were Juvisy, the first Parisian + meeting, Wolverhampton, and the Comte de Lambert's flight round the Eiffel + Tower at a height estimated at between 1,200 and 1,300 feet. This may be + included in the record of these aerial theatricals, since it was nothing + more. + </p> + <p> + Probably wakened to realisation of the possibilities of the aeroplane by + the Rheims Meeting, Germany turned out its first plane late in 1909. It + was known as the Grade monoplane, and was a blend of the Bleriot and + Santos-Dumont machines, with a tail suggestive of the Antoinette type. The + main frame took the form of a single steel tube, at the forward end of + which was rigged a triangular arrangement carrying the pilot's seat and + the landing wheels underneath, with the wing warping wires and stays + above. The sweep of the wings was rather similar to the later Taube + design, though the sweep back was not so pronounced, and the machine was + driven by a four-cylinder, 20 horse-power, air-cooled engine which drove a + two-bladed tractor propeller. In spite of Lilienthal's pioneer work years + before, this was the first power-driven German plane which actually flew. + </p> + <p> + Eleven months after the Rheims meeting came what may be reckoned the only + really notable aviation meeting on English soil, in the form of the + Bournemouth week, July 10th to 16th, 1910. This gathering is noteworthy + mainly in view of the amazing advance which it registered on the Rheims + performances. Thus, in the matter of altitude, Morane reached 4,107 feet + and Drexel came second with 2,490 feet. Audemars on a Demoiselle monoplane + made a flight of 17 miles 1,480 yards in 27 minutes 17.2 seconds, a great + flight for the little Demoiselle. Morane achieved a speed of 56.64 miles + per hour, and Grahame White climbed to 1,000 feet altitude in 6 minutes + 36.8 seconds. Machines carrying the Gnome engine as power unit took the + great bulk of the prizes, and British-built engines were far behind. + </p> + <p> + The Bournemouth Meeting will always be remembered with regret for the + tragedy of C. S. Rolls's death, which took place on the Tuesday, the + second day of the meeting. The first competition of the day was that for + the landing prize; Grahame White, Audemars, and Captain Dickson had landed + with varying luck, and Rolls, following on a Wright machine with a + tail-plane which ought never to have been fitted and was not part of the + Wright design, came down wind after a left-hand turn and turned left again + over the top of the stands in order to land up wind. He began to dive when + just clear of the stands, and had dropped to a height of 40 feet when he + came over the heads of the people against the barriers. Finding his + descent too steep, he pulled back his elevator lever to bring the nose of + the machine up, tipping down the front end of the tail to present an + almost flat surface to the wind. Had all gone well, the nose of the + machine would have been forced up, but the strain on the tail and its four + light supports was too great; the tail collapsed, the wind pressed down + the biplane elevator, and the machine dived vertically for the remaining + 20 feet of the descent, hitting the ground vertically and crumpling up. + Major Kennedy, first to reach the debris, found Rolls lying with his head + doubled under him on the overturned upper main plane; the lower plane had + been flung some few feet away with the engine and tanks under it. Rolls + was instantaneously killed by concussion of the brain. + </p> + <p> + Antithesis to the tragedy was Audemars on his Demoiselle, which was named + 'The Infuriated Grasshopper.' Concerning this, it was recorded at the time + that 'Nothing so excruciatingly funny as the action of this machine has + ever been seen at any aviation ground. The little two-cylinder engine pops + away with a sound like the frantic drawing of ginger beer corks; the + machine scutters along the ground with its tail well up; then down comes + the tail suddenly and seems to slap the ground while the front jumps up, + and all the spectators rock with laughter. The whole attitude and the + jerky action of the machine suggest a grasshopper in a furious rage, and + the impression is intensified when it comes down, as it did twice on + Wednesday, in long grass, burying its head in the ground in its temper.'—(The + Aero, July, 1910.) + </p> + <p> + The Lanark Meeting followed in August of the same year, and with the bare + mention of this, the subject of flying meetings may he left alone, since + they became mere matters of show until there came military competitions + such as the Berlin Meeting at the end of August, 1910, and the British War + office Trials on Salisbury Plain, when Cody won his greatest triumphs. The + Berlin meeting proved that, from the time of the construction of the first + successful German machine mentioned above, to the date of the meeting, a + good number of German aviators had qualified for flight, but principally + on Wright and Antoinette machines, though by that time the Aviatik and + Dorner German makes had taken the air. The British War office Trials + deserve separate and longer mention. + </p> + <p> + In 1910 in spite of official discouragement, Captain Dickson proved the + value of the aeroplane for scouting purposes by observing movements of + troops during the Military Manoeuvres on Salisbury Plain. Lieut. Lancelot + Gibbs and Robert Loraine, the actor-aviator, also made flights over the + manoeuvre area, locating troops and in a way anticipating the formation + and work of the Royal Flying Corps by a usefulness which could not be + officially recognised. + </p> + <p> + <a name="link2H_4_0017" id="link2H_4_0017"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + XV. THE CHANNEL CROSSING + </h2> + <p> + It may be said that Louis Bleriot was responsible for the second great + landmark in the history of successful flight. The day when the brothers + Wright succeeded in accomplishing power-driven flight ranks as the first + of these landmarks. Ader may or may not have left the ground, but the + wreckage of his 'Avion' at the end of his experiment places his doubtful + success in a different category from that of the brothers Wright and + leaves them the first definite conquerors, just as Bleriot ranks as first + definite conqueror of the English Channel by air. + </p> + <p> + In a way, Louis Bleriot ranks before Farman in point of time; his first + flapping-wing model was built as early as 1900, and Voisin flew a biplane + glider of his on the Seine in the very early experimental days. Bleriot's + first four machines were biplanes, and his fifth, a monoplane, was wrecked + almost immediately after its construction. Bleriot had studied Langley's + work to a certain extent, and his sixth construction was a double + monoplane based on the Langley principle. A month after he had wrecked + this without damaging himself—for Bleriot had as many miraculous + escapes as any of the other fliers-he brought out number seven, a fairly + average monoplane. It was in December of 1907 after a series of flights + that he wrecked this machine, and on its successor, in July of 1908, he + made a flight of over 8 minutes. Sundry flights, more or less successful, + including the first cross-country flight from Toury to Artenay, kept him + busy up to the beginning of November, 1908, when the wreckage in a fog of + the machine he was flying sent him to the building of 'number eleven,' the + famous cross-channel aeroplane. + </p> + <p> + Number eleven was shown at the French Aero Show in the Grand Palais and + was given its first trials on the 18th January, 1909. It was first fitted + with a R.E.P. motor and had a lifting area of 120 square feet, which was + later increased to 150 square feet. The framework was of oak and poplar + spliced and reinforced with piano wire; the weight of the machine was 47 + lbs. and the undercarriage weight a further 60 lbs., this consisting of + rubber cord shock absorbers mounted on two wheels. The R.E.P. motor was + found unsatisfactory, and a three-cylinder Anzani of 105 mm. bore and 120 + mm. stroke replaced it. An accident seriously damaged the machine on June + 2nd, but Bleriot repaired it and tested it at Issy, where between June + 19th and June 23rd he accomplished flights of 8, 12, 15, 16, and 36 + minutes. On July 4th he made a 50-minute flight and on the 13th flew from + Etampes to Chevilly. + </p> + <p> + A few further details of construction may be given: the wings themselves + and an elevator at the tail controlled the rate of ascent and descent, + while a rudder was also fitted at the tail. The steering lever, working on + a universally jointed shaft—forerunner of the modern joystick—controlled + both the rudder and the wings, while a pedal actuated the elevator. The + engine drove a two-bladed tractor screw of 6 feet 7 inches diameter, and + the angle of incidence of the wings was 20 degrees. Timed at Issy, the + speed of the machine was given as 36 miles an hour, and as Bleriot + accomplished the Channel flight of 20 miles in 37 minutes, he probably had + a slight following wind. + </p> + <p> + The Daily Mail had offered a prize of L1,000 for the first Cross-Channel + flight, and Hubert Latham set his mind on winning it. He put up a shelter + on the French coast at Sangatte, half-way between Calais and Cape Blanc + Nez. From here he made his first attempt to fly to England on Monday the + 19th of July. He soared to a fair height, circling, and reached an + estimated height of about 900 feet as he came over the water with every + appearance of capturing the Cross-Channel prize. The luck which dogged his + career throughout was against him, for, after he had covered some 8 miles, + his engine stopped and he came down to the water in a series of long + glides. It was discovered afterward that a small piece of wire had worked + its way into a vital part of the engine to rob Latham of the honour he + coveted. The tug that came to his rescue found him seated on the fuselage + of his Antoinette, smoking a cigarette and waiting for a boat to take him + to the tug. It may be remarked that Latham merely assumed his Antoinette + would float in case he failed to make the English coast; he had no actual + proof. + </p> + <p> + Bleriot immediately entered his machine for the prize and took up his + quarters at Barraques. On Sunday, July 25th, 1909, shortly after 4 a.m., + Bleriot had his machine taken out from its shelter and prepared for + flight. He had been recently injured in a petrol explosion and hobbled out + on crutches to make his cross-Channel attempt; he made two great circles + in the air to try the machine, and then alighted. 'In ten minutes I start + for England,' he declared, and at 4.35 the motor was started up. After a + run of 100 yards, the machine rose in the air and got a height of about + 100 feet over the land, then wheeling sharply seaward and heading for + Dover. + </p> + <p> + Bleriot had no means of telling direction, and any change of wind might + have driven him out over the North Sea, to be lost, as were Cecil Grace + and Hamel later on. Luck was with him, however, and at 5.12 a.m. of that + July Sunday, he made his landing in the North Fall meadow, just behind + Dover Castle. Twenty minutes out from the French coast, he lost sight of + the destroyer which was patrolling the Channel, and at the same time he + was out of sight of land without compass or any other means of + ascertaining his direction. Sighting the English coast, he found that he + had gone too far to the east, for the wind increased in strength + throughout the flight, this to such an extent as almost to turn the + machine round when he came over English soil. Profiting by Latham's + experience, Bleriot had fitted an inflated rubber cylinder a foot in + diameter by 5 feet in length along the middle of his fuselage, to render + floating a certainty in case he had to alight on the water. + </p> + <p> + Latham in his camp at Sangatte had been allowed to sleep through the calm + of the early morning through a mistake on the part of a friend, and when + his machine was turned out—in order that he might emulate Bleriot, + although he no longer hoped to make the first flight, it took so long to + get the machine ready and dragged up to its starting-point that there was + a 25 mile an hour wind by the time everything was in readiness. Latham was + anxious to make the start in spite of the wind, but the Directors of the + Antoinette Company refused permission. It was not until two days later + that the weather again became favourable, and then with a fresh machine, + since the one on which he made his first attempt had been very badly + damaged in being towed ashore, he made a circular trial flight of about 5 + miles. In landing from this, a side gust of wind drove the nose of the + machine against a small hillock, damaging both propeller blades and + chassis, and it was not until evening that the damage was repaired. + </p> + <p> + French torpedo boats were set to mark the route, and Latham set out on his + second attempt at six o'clock. Flying at a height of 200 feet, he headed + over the torpedo boats for Dover and seemed certain of making the English + coast, but a mile and a half out from Dover his engine failed him again, + and he dropped to the water to be picked up by the steam pinnace of an + English warship and put aboard the French destroyer Escopette. + </p> + <p> + There is little to choose between the two aviators for courage in + attempting what would have been considered a foolhardy feat a year or two + before. Bleriot's state, with an abscess in the burnt foot which had to + control the elevator of his machine, renders his success all the more + remarkable. His machine was exhibited in London for a time, and was + afterwards placed in the Conservatoire des Arts et Metiers, while a + memorial in stone, copying his monoplane in form, was let into the turf at + the point where he landed. + </p> + <p> + The second Channel crossing was not made until 1910, a year of new + records. The altitude record had been lifted to over 10,000 feet, the + duration record to 8 hours 12 minutes, and the distance for a single + flight to 365 miles, while a speed of over 65 miles an hour had been + achieved, when Jacques de Lesseps, son of the famous engineer of Suez + Canal and Panama fame, crossed from France to England on a Bleriot + monoplane. By this time flying had dropped so far from the marvellous that + this second conquest of the Channel aroused but slight public interest in + comparison with Bleriot's feat. + </p> + <p> + The total weight of Bleriot's machine in Cross Channel trim was 660 lbs., + including the pilot and sufficient petrol for a three hours' run; at a + speed of 37 miles an hour, it was capable of carrying about 5 lbs. per + square foot of lifting surface. It was the three-cylinder 25 horse-power + Anzani motor which drove the machine for the flight. Shortly after the + flight had been accomplished, it was announced that the Bleriot firm would + construct similar machines for sale at L400 apiece—a good commentary + on the prices of those days. + </p> + <p> + On June the 2nd, 1910, the third Channel crossing was made by C. S. Rolls, + who flew from Dover, got himself officially observed over French soil at + Barraques, and then flew back without landing. He was the first to cross + from the British side of the Channel and also was the first aviator who + made the double journey. By that time, however, distance flights had so + far increased as to reduce the value of the feat, and thenceforth the + Channel crossing was no exceptional matter. The honour, second only to + that of the Wright Brothers, remains with Bleriot. + </p> + <p> + <a name="link2H_4_0018" id="link2H_4_0018"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + XVI. LONDON TO MANCHESTER + </h2> + <p> + The last of the great contests to arouse public enthusiasm was the London + to Manchester Flight of 1910. As far back as 1906, the Daily Mail had + offered a prize of L10,000 to the first aviator who should accomplish this + journey, and, for a long time, the offer was regarded as a perfectly safe + one for any person or paper to make—it brought forth far more + ridicule than belief. Punch offered a similar sum to the first man who + should swim the Atlantic and also for the first flight to Mars and back + within a week, but in the spring of 1910 Claude Grahame White and Paulhan, + the famous French pilot, entered for the 183 mile run on which the prize + depended. Both these competitors flew the Farman biplane with the 50 + horse-power Gnome motor as propulsive power. Grahame White surveyed the + ground along the route, and the L. & N. W. Railway Company, at his + request, whitewashed the sleepers for 100 yards on the north side of all + junctions to give him his direction on the course. The machine was run out + on to the starting ground at Park Royal and set going at 5.19 a.m. on + April 23rd. After a run of 100 yards, the machine went up over Wormwood + Scrubs on its journey to Normandy, near Hillmorten, which was the first + arranged stopping place en route; Grahame White landed here in good trim + at 7.20 a.m., having covered 75 miles and made a world's record cross + country flight. At 8.15 he set off again to come down at Whittington, four + miles short of Lichfield, at about 9.20, with his machine in good order + except for a cracked landing skid. Twice, on this second stage of the + journey, he had been caught by gusts of wind which turned the machine + fully round toward London, and, when over a wood near Tamworth, the engine + stopped through a defect in the balance springs of two exhaust valves; + although it started up again after a 100 foot glide, it did not give + enough power to give him safety in the gale he was facing. The rising wind + kept him on the ground throughout the day, and, though he hoped for better + weather, the gale kept up until the Sunday evening. The men in charge of + the machine during its halt had attempted to hold the machine down instead + of anchoring it with stakes and ropes, and, in consequence of this, the + wind blew the machine over on its back, breaking the upper planes and the + tail. Grahame White had to return to London, while the damaged machine was + prepared for a second flight. The conditions of the competition enacted + that the full journey should be completed within 24 hours, which made + return to the starting ground inevitable. + </p> + <p> + Louis Paulhan, who had just arrived with his Farman machine, immediately + got it unpacked and put together in order to be ready to make his attempt + for the prize as soon as the weather conditions should admit. At 5.31 + p.m., on April 27th, he went up from Hendon and had travelled 50 miles + when Grahame White, informed of his rival's start, set out to overtake + him. Before nightfall Paulhan landed at Lichfield, 117 miles from London, + while Grahame White had to come down at Roden, only 60 miles out. The + English aviator's chance was not so small as it seemed, for, as Latham had + found in his cross-Channel attempts, engine failure was more the rule than + the exception, and a very little thing might reverse the relative + positions. + </p> + <p> + A special train accompanied Paulhan along the North-Western route, + conveying Madame Paulhan, Henry Farman, and the mechanics who fitted the + Farman biplane together. Paulhan himself, who had flown at a height of + 1,000 feet, spent the night at Lichfield, starting again at 4.9 a.m. On + the 28th, passing Stafford at 4.45, Crewe at 5.20, and landing at Burnage, + near Didsbury, at 5.32, having had a clean run. + </p> + <p> + Meanwhile, Grahame White had made a most heroic attempt to beat his rival. + An hour before dawn on the 28th, he went to the small field in which his + machine had landed, and in the darkness managed to make an ascent from + ground which made starting difficult even in daylight. Purely by instinct + and his recollection of the aspect of things the night before, he had to + clear telegraph wires and a railway bridge, neither of which he could + possibly see at that hour. His engine, too, was faltering, and it was + obvious to those who witnessed his start that its note was far from + perfect. + </p> + <p> + At 3.50 he was over Nuneaton and making good progress; between Atherstone + and Lichfield the wind caught him and the engine failed more and more, + until at 4.13 in the morning he was forced to come to earth, having + covered 6 miles less distance than in his first attempt. It was purely a + case of engine failure, for, with full power, he would have passed over + Paulhan just as the latter was preparing for the restart. Taking into + consideration the two machines, there is little doubt that Grahame White + showed the greater flying skill, although he lost the prize. After landing + and hearing of Paulhan's victory, on which he wired congratulations, he + made up his mind to fly to Manchester within the 24 hours. He started at 5 + o'clock in the afternoon from Polesworth, his landing place, but was + forced to land at 5.30 at Whittington, where he had landed on the previous + Saturday. The wind, which had forced his descent, fell again and permitted + of starting once more; on this third stage he reached Lichfield, only to + make his final landing at 7.15 p.m., near the Trent Valley station. The + defective running of the Gnome engine prevented his completing the course, + and his Farman machine had to be brought back to London by rail. + </p> + <p> + The presentation of the prize to Paulhan was made the occasion for the + announcement of a further competition, consisting of a 1,000 mile flight + round a part of Great Britain. In this, nineteen competitors started, and + only four finished; the end of the race was a great fight between Beaumont + and Vedrines, both of whom scorned weather conditions in their + determination to win. Beaumont made the distance in a flying time of 22 + hours 28 minutes 19 seconds, and Vedrines covered the journey in a little + over 23 1/2 hours. Valentine came third on a Deperdussin monoplane and S. + F. Cody on his Cathedral biplane was fourth. This was in 1911, and by that + time heavier-than-air flight had so far advanced that some pilots had had + war experience in the Italian campaign in Tripoli, while long + cross-country flights were an everyday event, and bad weather no longer + counted. + </p> + <p> + <a name="link2H_4_0019" id="link2H_4_0019"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + XVII. A SUMMARY, TO 1911 + </h2> + <p> + There is so much overlapping in the crowded story of the first years of + successful power-driven flight that at this point it is advisable to make + a concise chronological survey of the chief events of the period of early + development, although much of this is of necessity recapitulation. The + story begins, of course, with Orville Wright's first flight of 852 feet at + Kitty Hawk on December 19th, 1903. The next event of note was Wright's + flight of 11.12 miles in 18 minutes 9 seconds at Dayton, Ohio, on + September 26th, 1905, this being the first officially recorded flight. On + October 4th of the same year, Wright flew 20.75 miles in 33 minutes 17 + seconds, this being the first flight of over 20 miles ever made. Then on + September 14th 1906, Alberto Santos-Dumont made a flight of eight seconds + on the second heavier-than-air machine he had constructed. It was a big + box-kite-like machine; this was the second power-driven aeroplane in + Europe to fly, for although Santos-Dumont's first machine produced in 1905 + was reckoned an unsuccessful design, it had actually got off the ground + for brief periods. Louis Bleriot came into the ring on April 5th, 1907, + with a first flight of 6 seconds on a Bleriot monoplane, his eighth but + first successful construction. + </p> + <p> + Henry Farman made his first appearance in the history of aviation with a + flight of 935 feet on a Voisin biplane on October 15th 1907. On October + 25th, in a flight of 2,530 feet, he made the first recorded turn in the + air, and on March 29th, 1908, carrying Leon Delagrange on a Voisin + biplane, he made the first passenger flight. On April 10th of this year, + Delagrange, in flying 1 1/2 miles, made the first flight in Europe + exceeding a mile in distance. He improved on this by flying 10 1/2 miles + at Milan on June 22nd, while on July 8th, at Turin, he took up Madame + Peltier, the first woman to make an aeroplane flight. + </p> + <p> + Wilbur Wright, coming over to Europe, made his first appearance on the + Continent with a flight of 1 3/4 minutes at Hunaudieres, France, on August + 8th, 1908. On September 6th, at Chalons, he flew for 1 hour 4 minutes 26 + seconds with a passenger, this being the first flight in which an hour in + the air was exceeded with a passenger on board. + </p> + <p> + On September 12th 1908, Orville Wright, flying at Fort Meyer, U.S.A., with + Lieut. Selfridge as passenger, crashed his machine, suffering severe + injuries, while Selfridge was killed. This was the first aeroplane + fatality. On October 30th, 1908, Farman made the first cross-country + flight, covering the distance of 17 miles between Bouy and Rheims. The + next day, Louis Bleriot, in flying from Toury to Artenay, made two + landings en route, this being the first cross-country flight with + landings. On the last day of the year, Wilbur Wright won the Michelin Cup + at Auvours with a flight of 90 miles, which, lasting 2 hours 20 minutes 23 + seconds, exceeded 2 hours in the air for the first time. + </p> + <p> + On January 2nd, 1909, S. F. Cody opened the New Year by making the first + observed flight at Farnborough on a British Army aeroplane. It was not + until July 18th of 1909 that the first European height record deserving of + mention was put up by Paulhan, who achieved a height of 450 feet on a + Voisin biplane. This preceded Latham's first attempt to fly the Channel by + two days, and five days later, on the 25th of the month, Bleriot made the + first Channel crossing. The Rheims Meeting followed on August 22nd, and it + was a great day for aviation when nine machines were seen in the air at + once. It was here that Farman, with a 118 mile flight, first exceeded the + hundred miles, and Latham raised the height record officially to 500 feet, + though actually he claimed to have reached 1,200 feet. On September 8th, + Cody, flying from Aldershot, made a 40 mile journey, setting up a new + cross-country record. On October 19th the Comte de Lambert flew from + Juvisy to Paris, rounded the Eiffel Tower and flew back. J. T. C. + Moore-Brabazon made the first circular mile flight by a British aviator on + an all-British machine in Great Britain, on October 30th, flying a Short + biplane with a Green engine. Paulhan, flying at Brooklands on November + 2nd, accomplished 96 miles in 2 hours 48 minutes, creating a British + distance record; on the following day, Henry Farman made a flight of 150 + miles in 4 hours 22 minutes at Mourmelon, and on the 5th of the month, + Paulhan, flying a Farman biplane, made a world's height record of 977 + feet. This, however, was not to stand long, for Latham got up to 1,560 + feet on an Antoinette at Mourmelon on December 1st. December 31st + witnessed the first flight in Ireland, made by H. Ferguson on a monoplane + which he himself had constructed at Downshire Park, Lisburn. + </p> + <p> + These, thus briefly summarised, are the principal events up to the end of + 1909. 1910 opened with tragedy, for on January 4th Leon Delagrange, one of + the greatest pilots of his time, was killed while flying at Pau. The + machine was the Bleriot XI which Delagrange had used at the Doncaster + meeting, and to which Delagrange had fitted a 50 horse-power Gnome engine, + increasing the speed of the machine from its original 30 to 45 miles per + hour. With the Rotary Gnome engine there was of necessity a certain + gyroscopic effect, the strain of which proved too much for the machine. + Delagrange had come to assist in the inauguration of the Croix d'Hins + aerodrome, and had twice lapped the course at a height of about 60 feet. + At the beginning of the third lap, the strain of the Gnome engine became + too great for the machine; one wing collapsed as if the stay wires had + broken, and the whole machine turned over and fell, killing Delagrange. + </p> + <p> + On January 7th Latham, flying at Mourmelon, first made the vertical + kilometre and dedicated the record to Delagrange, this being the day of + his friend's funeral. The record was thoroughly authenticated by a large + registering barometer which Latham carried, certified by the officials of + the French Aero Club. Three days later Paulhan, who was at Los Angeles, + California, raised the height record to 4,146 feet. + </p> + <p> + On January 25th the Brussels Exhibition opened, when the Antoinette + monoplane, the Gaffaux and Hanriot monoplanes, together with the d'Hespel + aeroplane, were shown; there were also the dirigible Belgica and a number + of interesting aero engines, including a German airship engine and a + four-cylinder 50 horse-power Miesse, this last air-cooled by means of 22 + fans driving a current of air through air jackets surrounding fluted + cylinders. + </p> + <p> + On April 2nd Hubert Le Blon, flying a Bleriot with an Anzani engine, was + killed while flying over the water. His machine was flying quite steadily, + when it suddenly heeled over and came down sideways into the sea; the + motor continued running for some seconds and the whole machine was drawn + under water. When boats reached the spot, Le Blon was found lying back in + the driving seat floating just below the surface. He had done good flying + at Doncaster, and at Heliopolis had broken the world's speed records for 5 + and 10 kilometres. The accident was attributed to fracture of one of the + wing stay wires when running into a gust of wind. + </p> + <p> + The next notable event was Paulhan's London-Manchester flight, of which + full details have already been given. In May Captain Bertram Dickson, + flying at the Tours meeting, beat all the Continental fliers whom he + encountered, including Chavez, the Peruvian, who later made the first + crossing of the Alps. Dickson was the first British winner of + international aviation prizes. + </p> + <p> + C. S. Rolls, of whom full details have already been given, was killed at + Bournemouth on July 12th, being the first British aviator of note to be + killed in an aeroplane accident. His return trip across the Channel had + taken place on June 2nd. Chavez, who was rapidly leaping into fame, as a + pilot, raised the British height record to 5,750 feet while flying at + Blackpool on August 3rd. On the 11th of that month, Armstrong Drexel, + flying a Bleriot, made a world's height record of 6,745 feet. + </p> + <p> + It was in 1910 that the British War office first began fully to realise + that there might be military possibilities in heavier-than-air flying. C. + S. Rolls had placed a Wright biplane at the disposal of the military + authorities, and Cody, as already recorded, had been experimenting with a + biplane type of his own for some long period. Such development as was + achieved was mainly due to the enterprise and energy of Colonel J. E. + Capper, C.B., appointed to the superintendency of the Balloon Factory and + Balloon School at Farnborough in 1906. Colonel Capper's retirement in 1910 + brought (then) Mr Mervyn O'Gorman to command, and by that time the series + of successes of the Cody biplane, together with the proved efficiency of + the aeroplane in various civilian meetings, had convinced the British + military authorities that the mastery of the air did not lie altogether + with dirigible airships, and it may be said that in 1910 the British War + office first began seriously to consider the possibilities of the + aeroplane, though two years more were to elapse before the formation of + the Royal Flying Corps marked full realisation of its value. + </p> + <p> + A triumph and a tragedy were combined in September of 1910. On the 23rd of + the month, Georges Chavez set out to fly across the Alps on a Bleriot + monoplane. Prizes had been offered by the Milan Aviation Committee for a + flight from Brigue in Switzerland over the Simplon Pass to Milan, a + distance of 94 miles with a minimum height of 6,600 feet above sea level. + Chavez started at 1.30 p.m. On the 23rd, and 41 minutes later he reached + Domodossola, 25 miles distant. Here he descended, numbed with the cold of + the journey; it was said that the wings of his machine collapsed when + about 30 feet from the ground, but however this may have been, he smashed + the machine on landing, and broke both legs, in addition to sustaining + other serious injuries. He lay in hospital until the 27th September, when + he died, having given his life to the conquest of the Alps. His death in + the moment of success was as great a tragedy as were those of Pilcher and + Lilienthal. + </p> + <p> + The day after Chavez's death, Maurice Tabuteau flew across the Pyrenees, + landing in the square at Biarritz. On December 30th, Tabuteau made a + flight of 365 miles in 7 hours 48 minutes. Farman, on December 18th, had + flown for over 8 hours, but his total distance was only 282 miles. The + autumn of this year was also noteworthy for the fact that aeroplanes were + first successfully used in the French Military Manoeuvres. The British War + Office, by the end of the year, had bought two machines, a military type + Farman and a Paulhan, ignoring British experimenters and aeroplane + builders of proved reliability. These machines, added to an old Bleriot + two-seater, appear to have constituted the British aeroplane fleet of the + period. + </p> + <p> + There were by this time three main centres of aviation in England, apart + from Cody, alone on Laffan's Plain. These three were Brooklands, Hendon, + and the Isle of Sheppey, and of the three Brooklands was chief. Here such + men as Graham Gilmour, Rippen, Leake, Wickham, and Thomas persistently + experimented. Hendon had its own little group, and Shellbeach, Isle of + Sheppey, held such giants of those days as C. S. Rolls and Moore Brabazon, + together with Cecil Grace and Rawlinson. One or other, and sometimes all + of these were deserted on the occasion of some meeting or other, but they + were the points where the spade work was done, Brooklands taking chief + place. 'If you want the early history of flying in England, it is there,' + one of the early school remarked, pointing over toward Brooklands course. + </p> + <p> + 1911 inaugurated a new series of records of varying character. On the 17th + January, E. B. Ely, an American, flew from the shore of San Francisco to + the U.S. cruiser Pennsylvania, landing on the cruiser, and then flew back + to the shore. The British military designing of aeroplanes had been taken + up at Farnborough by G. H. de Havilland, who by the end of January was + flying a machine of his own design, when he narrowly escaped becoming a + casualty through collision with an obstacle on the ground, which swept the + undercarriage from his machine. + </p> + <p> + A list of certified pilots of the countries of the world was issued early + in 1911, showing certificates granted up to the end of 1910. France led + the way easily with 353 pilots; England came next with 57, and Germany + next with 46; Italy owned 32, Belgium 27, America 26, and Austria 19; + Holland and Switzerland had 6 aviators apiece, while Denmark followed with + 3, Spain with 2, and Sweden with 1. The first certificate in England was + that of J. T. C. Moore-Brabazon, while Louis Bleriot was first on the + French list and Glenn Curtiss, first holder of an American certificate, + also held the second French brevet. + </p> + <p> + On the 7th March, Eugene Renaux won the Michelin Grand Prize by flying + from the French Aero Club ground at St Cloud and landing on the Puy de + Dome. The landing, which was one of the conditions of the prize, was one + of the most dangerous conditions ever attached to a competition; it + involved dropping on to a little plateau 150 yards square, with a + possibility of either smashing the machine against the face of the + mountain, or diving over the edge of the plateau into the gulf beneath. + The length of the journey was slightly over 200 miles and the height of + the landing point 1,465 metres, or roughly 4,500 feet above sea-level. + Renaux carried a passenger, Doctor Senoucque, a member of Charcot's South + Polar Expedition. + </p> + <p> + The 1911 Aero Exhibition held at Olympia bore witness to the enormous + strides made in construction, more especially by British designers, + between 1908 and the opening of the Show. The Bristol Firm showed three + machines, including a military biplane, and the first British built + biplane with tractor screw. The Cody biplane, with its enormous size + rendering it a prominent feature of the show, was exhibited. Its designer + anticipated later engines by expressing his desire for a motor of 150 + horse-power, which in his opinion was necessary to get the best results + from the machine. The then famous Dunne monoplane was exhibited at this + show, its planes being V-shaped in plan, with apex leading. It embodied + the results of very lengthy experiments carried out both with gliders and + power-driven machines by Colonel Capper, Lieut. Gibbs, and Lieut. Dunne, + and constituted the longest step so far taken in the direction of inherent + stability. + </p> + <p> + Such forerunners of the notable planes of the war period as the Martin + Handasyde, the Nieuport, Sopwith, Bristol, and Farman machines, were + features of the show; the Handley-Page monoplane, with a span of 32 feet + over all, a length of 22 feet, and a weight of 422 lbs., bore no relation + at all to the twin-engined giant which later made this firm famous. In the + matter of engines, the principal survivals to the present day, of which + this show held specimens, were the Gnome, Green, Renault air-cooled, + Mercedes four-cylinder dirigible engine of 115 horse-power, and 120 + horsepower Wolseley of eight cylinders for use with dirigibles. + </p> + <p> + On April 12th, of 1911, Paprier, instructor at the Bleriot school at + Hendon, made the first non-stop flight between London and Paris. He left + the aerodrome at 1.37 p.m., and arrived at Issy-les-Moulineaux at 5.33 + p.m., thus travelling 250 miles in a little under 4 hours. He followed the + railway route practically throughout, crossing from Dover to nearly + opposite Calais, keeping along the coast to Boulogne, and then following + the Nord Railway to Amiens, Beauvais, and finally Paris. + </p> + <p> + In May, the Paris-Madrid race took place; Vedrines, flying a Morane + biplane, carried off the prize by first completing the distance of 732 + miles. The Paris-Rome race of 916 miles was won in the same month by + Beaumont, flying a Bleriot monoplane. In July, Koenig won the German + National Circuit race of 1,168 miles on an Albatross biplane. This was + practically simultaneous with the Circuit of Britain won by Beaumont, who + covered 1,010 miles on a Bleriot monoplane, having already won the + Paris-Brussels-London-Paris Circuit of 1,080 miles, this also on a + Bleriot. It was in August that a new world's height record of 11,152 feet + was set up by Captain Felix at Etampes, while on the 7th of the month + Renaux flew nearly 600 miles on a Maurice Farman machine in 12 hours. Cody + and Valentine were keeping interest alive in the Circuit of Britain race, + although this had long been won, by determinedly plodding on at finishing + the course. + </p> + <p> + On September 9th, the first aerial post was tried between Hendon and + Windsor, as an experiment in sending mails by aeroplane. Gustave Hamel + flew from Hendon to Windsor and back in a strong wind. A few days later, + Hamel went on strike, refusing to carry further mails unless the promoters + of the Aerial Postal Service agreed to pay compensation to Hubert, who + fractured both his legs on the 11th of the month while engaged in aero + postal work. The strike ended on September 25th, when Hamel resumed + mail-carrying in consequence of the capitulation of the + Postmaster-General, who agreed to set aside L500 as compensation to + Hubert. + </p> + <p> + September also witnessed the completion in America of a flight across the + Continent, a distance of 2,600 miles. The only competitor who completed + the full distance was C. P. Rogers, who was disqualified through failing + to comply with the time limit. Rogers needed so many replacements to his + machine on the journey that, expressing it in American fashion, he arrived + with practically a dfferent aeroplane from that with which he started. + </p> + <p> + With regard to the aerial postal service, analysis of the matter carried + and the cost of the service seemed to show that with a special charge of + one shilling for letters and sixpence for post cards, the revenue just + balanced the expenditure. It was not possible to keep to the time-table + as, although the trials were made in the most favourable season of the + year, aviation was not sufficiently advanced to admit of facing all + weathers and complying with time-table regulations. + </p> + <p> + French military aeroplane trials took place at Rheims in October, the + noteworthy machines being Antoinette, Farman, Nieuport, and Deperdussin. + The tests showed the Nieuport monoplane with Gnome motor as first in + position; the Breguet biplane was second, and the Deperdussin monoplanes + third. The first five machines in order of merit were all engined with the + Gnome motor. + </p> + <p> + The records quoted for 1911 form the best evidence that can be given of + advance in design and performance during the year. It will be seen that + the days of the giants were over; design was becoming more and more + standardised and aviation not so much a matter of individual courage and + even daring, as of the reliability of the machine and its engine. This was + the first year in which the twin-engined aeroplane made its appearance, + and it was the year, too, in which flying may be said to have grown so + common that the 'meetings' which began with Rheims were hardly worth + holding, owing to the fact that increase in height and distance flown + rendered it no longer necessary for a would-be spectator of a flight to + pay half a crown and enter an enclosure. Henceforth, flying as a spectacle + was very little to be considered; its commercial aspects were talked of, + and to a very slight degree exploited, but, more and more, the fact that + the aeroplane was primarily an engine of war, and the growing German + menace against the peace of the world combined to point the way of + speediest development, and the arrangements for the British Military + Trials to be held in August, 1912, showed that even the British War office + was waking up to the potentialities of this new engine of war. + </p> + <p> + <a name="link2H_4_0020" id="link2H_4_0020"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + XVIII. A SUMMARY, TO 1914 + </h2> + <p> + Consideration of the events in the years immediately preceding the War + must be limited to as brief a summary as possible, this not only because + the full history of flying achievements is beyond the compass of any + single book, but also because, viewing the matter in perspective, the + years 1903-1911 show up as far more important as regards both design and + performance. From 1912 to August of 1914, the development of aeronautics + was hindered by the fact that it had not progressed far enough to form a + real commercial asset in any country. The meetings which drew vast + concourses of people to such places as Rheims and Bournemouth may have + been financial successes at first, but, as flying grew more common and + distances and heights extended, a great many people found it other than + worth while to pay for admission to an aerodrome. The business of taking + up passengers for pleasure flights was not financially successful, and, + although schemes for commercial routes were talked of, the aeroplane was + not sufficiently advanced to warrant the investment of hard cash in any of + these projects. There was a deadlock; further development was necessary in + order to secure financial aid, and at the same time financial aid was + necessary in order to secure further development. Consequently, neither + was forthcoming. + </p> + <p> + This is viewing the matter in a broad and general sense; there were firms, + especially in France, but also in England and America, which looked + confidently for the great days of flying to arrive, and regarded their + sunk capital as investment which would eventually bring its due return. + But when one looks back on those years, the firms in question stand out as + exceptions to the general run of people, who regarded aeronautics as + something extremely scientific, exceedingly dangerous, and very expensive. + The very fame that was attained by such pilots as became casualties + conduced to the advertisement of every death, and the dangers attendant on + the use of heavier-than-air machines became greatly exaggerated; + considering the matter as one of number of miles flown, even in the early + days, flying exacted no more toll in human life than did railways or road + motors in the early stages of their development. But to take one instance, + when C. S. Rolls was killed at Bournemouth by reason of a faulty + tail-plane, the fact was shouted to the whole world with almost as much + vehemence as characterised the announcement of the Titanic sinking in + mid-Atlantic. + </p> + <p> + Even in 1911 the deadlock was apparent; meetings were falling off in + attendance, and consequently in financial benefit to the promoters; there + remained, however, the knowledge—for it was proved past question—that + the aeroplane in its then stage of development was a necessity to every + army of the world. France had shown this by the more than interest taken + by the French Government in what had developed into an Air Section of the + French army; Germany, of course, was hypnotised by Count Zeppelin and his + dirigibles, to say nothing of the Parsevals which had been proved useful + military accessories; in spite of this, it was realised in Germany that + the aeroplane also had its place in military affairs. England came into + the field with the military aeroplane trials of August 1st to 15th, 1912, + barely two months after the founding of the Royal Flying Corps. + </p> + <p> + When the R.F.C. was founded—and in fact up to two years after its + founding—in no country were the full military potentialities of the + aeroplane realised; it was regarded as an accessory to cavalry for + scouting more than as an independent arm; the possibilities of bombing + were very vaguely considered, and the fact that it might be possible to + shoot from an aeroplane was hardly considered at all. The conditions of + the British Military Trials of 1912 gave to the War office the option of + purchasing for L1,000 any machine that might be awarded a prize. Machines + were required, among other things, to carry a useful load of 350 lbs. in + addition to equipment, with fuel and oil for 4 1/2-hours; thus loaded, + they were required to fly for 3 hours, attaining an altitude of 4,500 + feet, maintaining a height of 1,500 feet for 1 hour, and climbing 1,000 + feet from the ground at a rate of 200 feet per minute, 'although 300 feet + per minute is desirable.' They had to attain a speed of not less than 55 + miles per hour in a calm, and be able to plane down to the ground in a + calm from not more than 1,000 feet with engine stopped, traversing 6,000 + feet horizontal distance. For those days, the landing demands were rather + exacting; the machine should be able to rise without damage from long + grass, clover, or harrowed land, in 100 yards in a calm, and should be + able to land without damage on any cultivated ground, including rough + ploughed land, and, when landing on smooth turf in a calm, be able to pull + up within 75 yards of the point of first touching the ground. It was + required that pilot and observer should have as open a view as possible to + front and flanks, and they should be so shielded from the wind as to be + able to communicate with each other. These are the main provisions out of + the set of conditions laid down for competitors, but a considerable amount + of leniency was shown by the authorities in the competition, who obviously + wished to try out every machine entered and see what were its + capabilities. + </p> + <p> + The beginning of the competition consisted in assembling the machines + against time from road trim to flying trim. Cody's machine, which was the + only one to be delivered by air, took 1 hour and 35 minutes to assemble; + the best assembling time was that of the Avro, which was got into flying + trim in 14 minutes 30 seconds. This machine came to grief with Lieut. + Parke as pilot, on the 7th, through landing at very high speed on very bad + ground; a securing wire of the under-carriage broke in the landing, + throwing the machine forward on to its nose and then over on its back. + Parke was uninjured, fortunately; the damaged machine was sent off to + Manchester for repair and was back again on the 16th of August. + </p> + <p> + It is to be noted that by this time the Royal Aircraft Factory was + building aeroplanes of the B.E. and F.E. types, but at the same time it is + also to be noted that British military interest in engines was not + sufficient to bring them up to the high level attained by the planes, and + it is notorious that even the outbreak of war found England incapable of + providing a really satisfactory aero engine. In the 1912 Trials, the only + machines which actually completed all their tests were the Cody biplane, + the French Deperdussin, the Hanriot, two Bleriots and a Maurice Farman. + The first prize of L4,000, open to all the world, went to F. S. Cody's + British-built biplane, which complied with all the conditions of the + competition and well earned its official acknowledgment of supremacy. The + machine climbed at 280 feet per minute and reached a height of 5,000 feet, + while in the landing test, in spite of its great weight and bulk, it + pulled up on grass in 56 yards. The total weight was 2,690 lbs. when fully + loaded, and the total area of supporting surface was 500 square feet; the + motive power was supplied by a six-cylinder 120 horsepower Austro-Daimler + engine. The second prize was taken by A. Deperdussin for the French-built + Deperdussin monoplane. Cody carried off the only prize awarded for a + British-built plane, this being the sum of L1,000, and consolation prizes + of L500 each were awarded to the British Deperdussin Company and The + British and Colonial Aeroplane Company, this latter soon to become famous + as makers of the Bristol aeroplane, of which the war honours are still + fresh in men's minds. + </p> + <p> + While these trials were in progress Audemars accomplished the first flight + between Paris and Berlin, setting out from Issy early in the morning of + August 18th, landing at Rheims to refill his tanks within an hour and a + half, and then coming into bad weather which forced him to land + successively at Mezieres, Laroche, Bochum, and finally nearly + Gersenkirchen, where, owing to a leaky petrol tank, the attempt to win the + prize offered for the first flight between the two capitals had to be + abandoned after 300 miles had been covered, as the time limit was + definitely exceeded. Audemars determined to get through to Berlin, and set + off at 5 in the morning of the 19th, only to be brought down by fog; + starting off again at 9.15 he landed at Hanover, was off again at 1.35, + and reached the Johannisthal aerodrome in the suburbs of Berlin at 6.48 + that evening. + </p> + <p> + As early as 1910 the British Government possessed some ten aeroplanes, and + in 1911 the force developed into the Army Air Battalion, with the + aeroplanes under the control of Major J. H. Fulton, R.F.A. Toward the end + of 1911 the Air Battalion was handed over to (then) Brig.-Gen. D. + Henderson, Director of Military Training. On June 6th, 1912, the Royal + Flying Corps was established with a military wing under Major F. H. Sykes + and a naval wing under Commander C. R. Samson. A joint Naval and Military + Flying School was established at Upavon with Captain Godfrey M. Paine, + R.N., as Commandant and Major Hugh Trenchard as Assistant Commandant. The + Royal Aircraft Factory brought out the B.E. and F.E. types of biplane, + admittedly superior to any other British design of the period, and an + Aircraft Inspection Department was formed under Major J. H. Fulton. The + military wing of the R.F.C. was equipped almost entirely with machines of + Royal Aircraft Factory design, but the Navy preferred to develop British + private enterprise by buying machines from private firms. On July 1st, + 1914 the establishment of the Royal Naval Air Service marked the definite + separation of the military and naval sides of British aviation, but the + Central Flying School at Upavon continued to train pilots for both + services. + </p> + <p> + It is difficult at this length of time, so far as the military wing was + concerned, to do full justice to the spade work done by Major-General Sir + David Henderson in the early days. Just before war broke out, British + military air strength consisted officially of eight squadrons, each of 12 + machines and 13 in reserve, with the necessary complement of road + transport. As a matter of fact, there were three complete squadrons and a + part of a fourth which constituted the force sent to France at the + outbreak of war. The value of General Henderson's work lies in the fact + that, in spite of official stinginess and meagre supplies of every kind, + he built up a skeleton organisation so elastic and so well thought out + that it conformed to war requirements as well as even the German plans + fitted in with their aerial needs. On the 4th of August, 1914, the nominal + British air strength of the military wing was 179 machines. Of these, 82 + machines proceeded to France, landing at Amiens and flying to Maubeuge to + play their part in the great retreat with the British Expeditionary Force, + in which they suffered heavy casualties both in personnel and machines. + The history of their exploits, however, belongs to the War period. + </p> + <p> + The development of the aeroplane between 1912 and 1914 can be judged by + comparison of the requirements of the British War Office in 1912 with + those laid down in an official memorandum issued by the War Office in + February, 1914. This latter called for a light scout aeroplane, a + single-seater, with fuel capacity to admit of 300 miles range and a speed + range of from 50 to 85 miles per hour. It had to be able to climb 3,500 + feet in five minutes, and the engine had to be so constructed that the + pilot could start it without assistance. At the same time, a heavier type + of machine for reconnaissance work was called for, carrying fuel for a 200 + mile flight with a speed range of between 35 and 60 miles per hour, + carrying both pilot and observer. It was to be equipped with a wireless + telegraphy set, and be capable of landing over a 30 foot vertical obstacle + and coming to rest within a hundred yards' distance from the obstacle in a + wind of not more than 15 miles per hour. A third requirement was a heavy + type of fighting aeroplane accommodating pilot and gunner with machine gun + and ammunition, having a speed range of between 45 and 75 miles per hour + and capable of climbing 3,500 feet in 8 minutes. It was required to carry + fuel for a 300 mile flight and to give the gunner a clear field of fire in + every direction up to 30 degrees on each side of the line of flight. + Comparison of these specifications with those of the 1912 trials will show + that although fighting, scouting, and reconnaissance types had been + defined, the development of performance compared with the marvellous + development of the earlier years of achieved flight was small. + </p> + <p> + Yet the records of those years show that here and there an outstanding + design was capable of great things. On the 9th September, 1912, Vedrines, + flying a Deperdussin monoplane at Chicago, attained a speed of 105 miles + an hour. On August 12th, G. de Havilland took a passenger to a height of + 10,560 feet over Salisbury Plain, flying a B.E. biplane with a 70 + horse-power Renault engine. The work of de Havilland may be said to have + been the principal influence in British military aeroplane design, and + there is no doubt that his genius was in great measure responsible for the + excellence of the early B.E. and F.E. types. + </p> + <p> + On the 31st May, 1913, H. G. Hawker, flying at Brooklands, reached a + height of 11,450 feet on a Sopwith biplane engined with an 80 horse-power + Gnome engine. On June 16th, with the same type of machine and engine, he + achieved 12,900 feet. On the 2nd October, in the same year, a Grahame + White biplane with 120 horse-power Austro-Daimler engine, piloted by Louis + Noel, made a flight of just under 20 minutes carrying 9 passengers. In + France a Nieuport monoplane piloted by G. Legagneaux attained a height of + 6,120 metres, or just over 20,070 feet, this being the world's height + record. It is worthy of note that of the world's aviation records as + passed by the International Aeronautical Federation up to June 30th, 1914, + only one, that of Noel, is credited to Great Britain. + </p> + <p> + Just as records were made abroad, with one exception, so were the really + efficient engines. In England there was the Green engine, but the outbreak + of war found the Royal Flying Corps with 80 horse-power Gnomes, 70 + horse-power Renaults, and one or two Antoinette motors, but not one + British, while the Royal Naval Air Service had got 20 machines with + engines of similar origin, mainly land planes in which the wheeled + undercarriages had been replaced by floats. France led in development, and + there is no doubt that at the outbreak of war, the French military + aeroplane service was the best in the world. It was mainly composed of + Maurice Farman two-seater biplanes and Bleriot monoplanes—the latter + type banned for a period on account of a number of serious accidents that + took place in 1912. + </p> + <p> + America had its Army Aviation School, and employed Burgess-Wright and + Curtiss machines for the most part. In the pre-war years, once the Wright + Brothers had accomplished their task, America's chief accomplishment + consisted in the development of the 'Flying Boat,' alternatively named + with characteristic American clumsiness, 'The Hydro-Aeroplane.' In + February of 1911, Glenn Curtiss attached a float to a machine similar to + that with which he won the first Gordon-Bennett Air Contest and made his + first flying boat experiment. From this beginning he developed the boat + form of body which obviated the use and troubles of floats—his + hydroplane became its own float. + </p> + <p> + Mainly owing to greater engine reliability the duration records steadily + increased. By September of 1912 Fourny, on a Maurice Farman biplane, was + able to accomplish a distance of 628 miles without a landing, remaining in + the air for 13 hours 17 minutes and just over 57 seconds. By 1914 this was + raised by the German aviator, Landemann, to 21 hours 48 3/4 seconds. The + nature of this last record shows that the factors in such a record had + become mere engine endurance, fuel capacity, and capacity of the pilot to + withstand air conditions for a prolonged period, rather than any + exceptional flying skill. + </p> + <p> + Let these years be judged by the records they produced, and even then they + are rather dull. The glory of achievement such as characterised the work + of the Wright Brothers, of Bleriot, and of the giants of the early days, + had passed; the splendid courage, the patriotism and devotion of the + pilots of the War period had not yet come to being. There was progress, + past question, but it was mechanical, hardly ever inspired. The study of + climatic conditions was definitely begun and aeronautical meteorology came + to being, while another development already noted was the fitting of + wireless telegraphy to heavier-than-air machines, as instanced in the + British War office specification of February, 1914. These, however, were + inevitable; it remained for the War to force development beyond the + inevitable, producing in five years that which under normal circumstances + might easily have occupied fifty—the aeroplane of to-day; for, as + already remarked, there was a deadlock, and any survey that may be made of + the years 1912-1914, no matter how superficial, must take it into account + with a view to retaining correct perspective in regard to the development + of the aeroplane. + </p> + <p> + There is one story of 1914 that must be included, however briefly, in any + record of aeronautical achievement, since it demonstrates past question + that to Professor Langley really belongs the honour of having achieved a + design which would ensure actual flight, although the series of accidents + which attended his experiments gave to the Wright Brothers the honour of + first leaving the earth and descending without accident in a power-driven + heavier-than-air machine. In March, 1914, Glenn Curtiss was invited to + send a flying boat to Washington for the celebration of 'Langley Day,' + when he remarked, 'I would like to put the Langley aeroplane itself in the + air.' In consequence of this remark, Secretary Walcot of the Smithsonian + Institution authorised Curtiss to re-canvas the original Langley aeroplane + and launch it either under its own power or with a more recent engine and + propeller. Curtiss completed this, and had the machine ready on the shores + of Lake Keuka, Hammondsport, N.Y., by May. The main object of these + renewed trials was to show whether the original Langley machine was + capable of sustained free flight with a pilot, and a secondary object was + to determine more fully the advantages of the tandem monoplane type; thus + the aeroplane was first flown as nearly as possible in its original + condition, and then with such modifications as seemed desirable. The only + difference made for the first trials consisted in fitting floats with + connecting trusses; the steel main frame, wings, rudders, engine, and + propellers were substantially as they had been in 1903. The pilot had the + same seat under the main frame and the same general system of control. He + could raise or lower the craft by moving the rear rudder up and down; he + could steer right or left by moving the vertical rudder. He had no + ailerons nor wing-warping mechanism, but for lateral balance depended on + the dihedral angle of the wings and upon suitable movements of his weight + or of the vertical rudder. + </p> + <p> + After the adjustments for actual flight had been made in the Curtiss + factory, according to the minute descriptions contained in the Langley + Memoir on Mechanical Flight, the aeroplane was taken to the shore of Lake + Keuka, beside the Curtiss hangars, and assembled for launching. On a clear + morning (May 28th) and in a mild breeze, the craft was lifted on to the + water by a dozen men and set going, with Mr Curtiss at the steering wheel, + esconced in the little boat-shaped car under the forward part of the + frame. The four-winged craft, pointed somewhat across the wind, went + skimming over the waveless, then automatically headed into the wind, rose + in level poise, soared gracefully for 150 feet, and landed softly on the + water near the shore. Mr Curtiss asserted that he could have flown + farther, but, being unused to the machine, imagined that the left wings + had more resistance than the right. The truth is that the aeroplane was + perfectly balanced in wing resistance, but turned on the water like a + weather vane, owing to the lateral pressure on its big rear rudder. Hence + in future experiments this rudder was made turnable about a vertical axis, + as well as about the horizontal axis used by Langley. Henceforth the + little vertical rudder under the frame was kept fixed and inactive.[*] + </p> + <p> + That the Langley aeroplane was subsequently fitted with an 80 horse-power + Curtiss engine and successfully flown is of little interest in such a + record as this, except for the fact that with the weight nearly doubled by + the new engine and accessories the machine flew successfully, and + demonstrated the perfection of Langley's design by standing the strain. + The point that is of most importance is that the design itself proved a + success and fully vindicated Langley's work. At the same time, it would be + unjust to pass by the fact of the flight without according to Curtiss due + recognition of the way in which he paid tribute to the genius of the + pioneer by these experiments. + </p> + <p> + [*] Smithsonian Publications No. 2329. + </p> + <p> + <a name="link2H_4_0021" id="link2H_4_0021"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + XIX. THE WAR PERIOD—I + </h2> + <p> + Full record of aeronautical progress and of the accomplishments of pilots + in the years of the War would demand not merely a volume, but a complete + library, and even then it would be barely possible to pay full tribute to + the heroism of pilots of the war period. There are names connected with + that period of which the glory will not fade, names such as Bishop, + Guynemer, Boelcke, Ball, Fonck, Immelmann, and many others that spring to + mind as one recalls the 'Aces' of the period. In addition to the pilots, + there is the stupendous development of the machines—stupendous when + the length of the period in which it was achieved is considered. + </p> + <p> + The fact that Germany was best prepared in the matter of heavier-than-air + service machines in spite of the German faith in the dirigible is one more + item of evidence as to who forced hostilities. The Germans came into the + field with well over 600 aeroplanes, mainly two-seaters of standardised + design, and with factories back in the Fatherland turning out sufficient + new machines to make good the losses. There were a few single-seater + scouts built for speed, and the two-seater machines were all fitted with + cameras and bomb-dropping gear. Manoeuvres had determined in the German + mind what should be the uses of the air fleet; there was photography of + fortifications and field works; signalling by Very lights; spotting for + the guns, and scouting for news of enemy movements. The methodical German + mind had arranged all this beforehand, but had not allowed for the fact + that opponents might take counter-measures which would upset the + over-perfect mechanism of the air service just as effectually as the great + march on Paris was countered by the genius of Joffre. + </p> + <p> + The French Air Force at the beginning of the War consisted of upwards of + 600 machines. These, unlike the Germans, were not standardised, but were + of many and diverse types. In order to get replacements quickly enough, + the factories had to work on the designs they had, and thus for a long + time after the outbreak of hostilities standardisation was an + impossibility. The versatility of a Latin race in a measure compensated + for this; from the outset, the Germans tried to overwhelm the French Air + Force, but failed, since they had not the numerical superiority, nor—this + equally a determining factor—the versatility and resource of the + French pilots. They calculated on a 50 per cent superiority to ensure + success; they needed more nearly 400 per cent, for the German fought to + rule, avoiding risks whenever possible, and definitely instructed to save + both machines and pilots wherever possible. French pilots, on the other + hand, ran all the risks there were, got news of German movements, bombed + the enemy, and rapidly worked up a very respectable antiaircraft force + which, whatever it may have accomplished in the way of hitting German + planes, got on the German pilots' nerves. + </p> + <p> + It has already been detailed how Britain sent over 82 planes as its + contribution to the military aerial force of 1914. These consisted of + Farman, Caudron, and Short biplanes, together with Bleriot, Deperdussin + and Nieuport monoplanes, certain R.A.F. types, and other machines of which + even the name barely survives—the resourceful Yankee entitles them + 'orphans.' It is on record that the work of providing spares might have + been rather complicated but for the fact that there were none. + </p> + <p> + There is no doubt that the Germans had made study of aerial military needs + just as thoroughly as they had perfected their ground organisation. Thus + there were 21 illuminated aircraft stations in Germany before the War, the + most powerful being at Weimar, where a revolving electric flash of over 27 + million candle-power was located. Practically all German aeroplane tests + in the period immediately preceding the War were of a military nature, and + quite a number of reliability tests were carried out just on the other + side of the French frontier. Night flying and landing were standardised + items in the German pilot's course of instruction while they were still + experimental in other countries, and a system of signals was arranged + which rendered the instructional course as perfect as might be. + </p> + <p> + The Belgian contribution consisted of about twenty machines fit for active + service and another twenty which were more or less useful as training + machines. The material was mainly French, and the Belgian pilots used it + to good account until German numbers swamped them. France, and to a small + extent England, kept Belgian aviators supplied with machines throughout + the War. + </p> + <p> + The Italian Air Fleet was small, and consisted of French machines together + with a percentage of planes of Italian origin, of which the design was + very much a copy of French types. It was not until the War was nearing its + end that the military and naval services relied more on the home product + than on imports. This does not apply to engines, however, for the F.I.A.T. + and S.C.A.T. were equal to practically any engine of Allied make, both in + design and construction. + </p> + <p> + Russia spent vast sums in the provision of machines: the giant Sikorsky + biplane, carrying four 100 horsepower Argus motors, was designed by a + young Russian engineer in the latter part of 1913, and in its early trials + it created a world's record by carrying seven passengers for 1 hour 54 + minutes. Sikorsky also designed several smaller machines, tractor biplanes + on the lines of the British B.E. type, which were very successful. These + were the only home productions, and the imports consisted mainly of French + aeroplanes by the hundred, which got as far as the docks and railway + sidings and stayed there, while German influence and the corruption that + ruined the Russian Army helped to lose the War. A few Russian aircraft + factories were got into operation as hostilities proceeded, but their + products were negligible, and it is not on record that Russia ever learned + to manufacture a magneto. + </p> + <p> + The United States paid tribute to British efficiency by adopting the + British system of training for its pilots; 500 American cadets were + trained at the School of Military Aeronautics at oxford, in order to form + a nucleus for the American aviation schools which were subsequently set up + in the United States and in France. As regards production of craft, the + designing of the Liberty engine and building of over 20,000 aeroplanes + within a year proves that America is a manufacturing country, even under + the strain of war. + </p> + <p> + There were three years of struggle for aerial supremacy, the combatants + being England and France against Germany, and the contest was neck and + neck all the way. Germany led at the outset with the standardised + two-seater biplanes manned by pilots and observers, whose training was + superior to that afforded by any other nation, while the machines + themselves were better equipped and fitted with accessories. All the early + German aeroplanes were designated Taube by the uninitiated, and were + formed with swept-back, curved wings very much resembling the wings of a + bird. These had obvious disadvantages, but the standardisation of design + and mass production of the German factories kept them in the field for a + considerable period, and they flew side by side with tractor biplanes of + improved design. For a little time, the Fokker monoplane became a definite + threat both to French and British machines. It was an improvement on the + Morane French monoplane, and with a high-powered engine it climbed quickly + and flew fast, doing a good deal of damage for a brief period of 1915. + Allied design got ahead of it and finally drove it out of the air. + </p> + <p> + German equipment at the outset, which put the Allies at a disadvantage, + included a hand-operated magneto engine-starter and a small independent + screw which, mounted on one of the main planes, drove the dynamo used for + the wireless set. Cameras were fitted on practically every machine; + equipment included accurate compasses and pressure petrol gauges, speed + and height recording instruments, bomb-dropping fittings and sectional + radiators which facilitated repairs and gave maximum engine efficiency in + spite of variations of temperature. As counter to these, the Allied pilots + had resource amounting to impudence. In the early days they carried rifles + and hand grenades and automatic pistols. They loaded their machines down, + often at their own expense, with accessories and fittings until their + aeroplanes earned their title of Christmas trees. They played with death + in a way that shocked the average German pilot of the War's early stages, + declining to fight according to rule and indulging in the individual duels + of the air which the German hated. As Sir John French put it in one of his + reports, they established a personal ascendancy over the enemy, and in + this way compensated for their inferior material. + </p> + <p> + French diversity of design fitted in well with the initiative and resource + displayed by the French pilots. The big Caudron type was the ideal bomber + of the early days; Farman machines were excellent for reconnaissance and + artillery spotting; the Bleriots proved excellent as fighting scouts and + for aerial photography; the Nieuports made good fighters, as did the + Spads, both being very fast craft, as were the Morane-Saulnier monoplanes, + while the big Voisin biplanes rivalled the Caudron machines as bombers. + </p> + <p> + The day of the Fokker ended when the British B.E.2.C. aeroplane came to + France in good quantities, and the F.E. type, together with the De + Havilland machines, rendered British aerial superiority a certainty. + Germany's best reply—this was about 1916—was the Albatross + biplane, which was used by Captain Baron von Richthofen for his famous + travelling circus, manned by German star pilots and sent to various parts + of the line to hearten up German troops and aviators after any specially + bad strafe. Then there were the Aviatik biplane and the Halberstadt + fighting scout, a cleanly built and very fast machine with a powerful + engine with which Germany tried to win back superiority in the third year + of the War, but Allied design kept about three months ahead of that of the + enemy, once the Fokker had been mastered, and the race went on. Spads and + Bristol fighters, Sopwith scouts and F.E.'s played their part in the race, + and design was still advancing when peace came. + </p> + <p> + The giant twin-engined Handley-Page bomber was tried out, proved + efficient, and justly considered better than anything of its kind that had + previously taken the field. Immediately after the conclusion of its + trials, a specimen of the type was delivered intact at Lille for the + Germans to copy, the innocent pilot responsible for the delivery doing + some great disservice to his own cause. The Gotha Wagon-Fabrik Firm + immediately set to work and copied the Handley-Page design, producing the + great Gotha bombing machine which was used in all the later raids on + England as well as for night work over the Allied lines. + </p> + <p> + How the War advanced design may be judged by comparison of the military + requirements given for the British Military Trials of 1912, with + performances of 1916 and 1917, when the speed of the faster machines had + increased to over 150 miles an hour and Allied machines engaged enemy + aircraft at heights ranging up to 22,000 feet. All pre-war records of + endurance, speed, and climb went by the board, as the race for aerial + superiority went on. + </p> + <p> + Bombing brought to being a number of crude devices in the first year of + the War. Allied pilots of the very early days carried up bombs packed in a + small box and threw them over by hand, while, a little later, the bombs + were strung like apples on wings and undercarriage, so that the pilot who + did not get rid of his load before landing risked an explosion. Then came + a properly designed carrying apparatus, crude but fairly efficient, and + with 1916 development had proceeded as far as the proper bomb-racks with + releasing gear. + </p> + <p> + Reconnaissance work developed, so that fighting machines went as escort to + observing squadrons and scouting operations were undertaken up to 100 + miles behind the enemy lines; out of this grew the art of camouflage, when + ammunition dumps were painted to resemble herds of cows, guns were + screened by foliage or painted to merge into a ground scheme, and many + other schemes were devised to prevent aerial observation. Troops were + moved by night for the most part, owing to the keen eyes of the air pilots + and the danger of bombs, though occasionally the aviator had his chance. + There is one story concerning a British pilot who, on returning from a + reconnaissance flight, observed a German Staff car on the road under him; + he descended and bombed and machine—gunned the car until the German + General and his chauffeur abandoned it, took to their heels, and ran like + rabbits. Later still, when Allied air superiority was assured, there came + the phase of machine-gunning bodies of enemy troops from the air. + Disregarding all antiaircraft measures, machines would sweep down and + throw battalions into panic or upset the military traffic along a road, + demoralising a battery or a transport train and causing as much damage + through congestion of traffic as with their actual machine-gun fire. + Aerial photography, too, became a fine art; the ordinary long focus + cameras were used at the outset with automatic plate changers, but later + on photographing aeroplanes had cameras of wide angle lens type built into + the fuselage. These were very simply operated, one lever registering the + exposure and changing the plate. In many cases, aerial photographs gave + information which the human eye had missed, and it is noteworthy that + photographs of ground showed when troops had marched over it, while the + aerial observer was quite unable to detect the marks left by their + passing. + </p> + <p> + Some small mention must be made of seaplane activities, which, round the + European coasts involved in the War, never ceased. The submarine campaign + found in the spotting seaplane its greatest deterrent, and it is old news + now how even the deeply submerged submarines were easily picked out for + destruction from a height and the news wirelessed from seaplane to + destroyer, while in more than one place the seaplane itself finished the + task by bomb dropping. It was a seaplane that gave Admiral Beatty the news + that the whole German Fleet was out before the Jutland Battle, news which + led to a change of plans that very nearly brought about the destruction of + Germany's naval power. For the most part, the seaplanes of the War period + were heavier than the land machines and, in the opinion of the land + pilots, were slow and clumsy things to fly. This was inevitable, for their + work demanded more solid building and greater reliability. To put the + matter into Hibernian phrase, a forced landing at sea is a much more + serious matter than on the ground. Thus there was need for greater engine + power, bigger wingspread to support the floats, and fuel tanks of greater + capacity. The flying boats of the later War period carried considerable + crews, were heavily armed, capable of withstanding very heavy weather, and + carried good loads of bombs on long cruises. Their work was not all + essentially seaplane work, for the R.N.A.S. was as well known as hated + over the German airship sheds in Belgium and along the Flanders coast. As + regards other theatres of War, they rendered valuable service from the + Dardanelles to the Rufiji River, at this latter place forming a principal + factor in the destruction of the cruiser Konigsberg. Their spotting work + at the Dardanelles for the battleships was responsible for direct hits + from 15 in. guns on invisible targets at ranges of over 12,000 yards. + Seaplane pilots were bombing specialists, including among their targets + army headquarters, ammunition dumps, railway stations, submarines and + their bases, docks, shipping in German harbours, and the German Fleet at + Wilhelmshaven. Dunkirk, a British seaplane base, was a sharp thorn in the + German side. + </p> + <p> + Turning from consideration of the various services to the exploits of the + men composing them, it is difficult to particularise. A certain inevitable + prejudice even at this length of time leads one to discount the valour of + pilots in the German Air Service, but the names of Boelcke, von + Richthofen, and Immelmann recur as proof of the courage that was not + wanting in the enemy ranks, while, however much we may decry the Gotha + raids over the English coast and on London, there is no doubt that the men + who undertook these raids were not deficient in the form of bravery that + is of more value than the unthinking valour of a minute which, observed + from the right quarter, wins a military decoration. + </p> + <p> + Yet the fact that the Allied airmen kept the air at all in the early days + proved on which side personal superiority lay, for they were outnumbered, + out-manoeuvred, and faced by better material than any that they themselves + possessed; yet they won their fights or died. The stories of their deeds + are endless; Bishop, flying alone and meeting seven German machines and + crashing four; the battle of May 5th, 1915, when five heroes fought and + conquered twenty-seven German machines, ranging in altitude between 12,000 + and 3,000 feet, and continuing the extraordinary struggle from five until + six in the evening. Captain Aizlewood, attacking five enemy machines with + such reckless speed that he rammed one and still reached his aerodrome + safely—these are items in a long list of feats of which the + character can only be realised when it is fully comprehended that the + British Air Service accounted for some 8,000 enemy machines in the course + of the War. Among the French there was Captain Guynemer, who at the time + of his death had brought down fifty-four enemy machines, in addition to + many others of which the destruction could not be officially confirmed. + There was Fonck, who brought down six machines in one day, four of them + within two minutes. + </p> + <p> + There are incredible stories, true as incredible, of shattered men + carrying on with their work in absolute disregard of physical injury. + Major Brabazon Rees, V.C., engaged a big German battle-plane in September + of 1915 and, single-handed, forced his enemy out of action. Later in his + career, with a serious wound in the thigh from which blood was pouring, he + kept up a fight with an enemy formation until he had not a round of + ammunition left, and then returned to his aerodrome to get his wound + dressed. Lieutenants Otley and Dunning, flying in the Balkans, engaged a + couple of enemy machines and drove them off, but not until their petrol + tank had got a hole in it and Dunning was dangerously wounded in the leg. + Otley improvised a tourniquet, passed it to Dunning, and, when the latter + had bandaged himself, changed from the observer's to the pilot's seat, + plugged the bullet hole in the tank with his thumb and steered the machine + home. + </p> + <p> + These are incidents; the full list has not been, and can never be + recorded, but it goes to show that in the pilot of the War period there + came to being a new type of humanity, a product of evolution which fitted + a certain need. Of such was Captain West, who, engaging hostile troops, + was attacked by seven machines. Early in the engagement, one of his legs + was partially severed by an explosive bullet and fell powerless into the + controls, rendering the machine for the time unmanageable. Lifting his + disabled leg, he regained control of the machine, and although wounded in + the other leg, he manoeuvred his machine so skilfully that his observer + was able to get several good bursts into the enemy machines, driving them + away. Then, desperately wounded as he was, Captain West brought the + machine over to his own lines and landed safely. He fainted from loss of + blood and exhaustion, but on regaining consciousness, insisted on writing + his report. Equal to this was the exploit of Captain Barker, who, in + aerial combat, was wounded in the right and left thigh and had his left + arm shattered, subsequently bringing down an enemy machine in flames, and + then breaking through another hostile formation and reaching the British + lines. + </p> + <p> + In recalling such exploits as these, one is tempted on and on, for it + seems that the pilots rivalled each other in their devotion to duty, this + not confined to British aviators, but common practically to all services. + Sufficient instances have been given to show the nature of the work and + the character of the men who did it. + </p> + <p> + The rapid growth of aerial effort rendered it necessary in January of 1915 + to organise the Royal Flying Corps into separate wings, and in October of + the same year it was constituted in Brigades. In 1916 the Air Board was + formed, mainly with the object of co-ordinating effort and ensuring both + to the R.N.A.S. and to the R.F.C. adequate supplies of material as far as + construction admitted. Under the presidency of Lord Cowdray, the Air Board + brought about certain reforms early in 1917, and in November of that year + a separate Air Ministry was constituted, separating the Air Force from + both Navy and Army, and rendering it an independent force. On April 1st, + 1918, the Royal Air Force came into existence, and unkind critics in the + Royal Flying Corps remarked on the appropriateness of the date. At the end + of the War, the personnel of the Royal Air Force amounted to 27,906 + officers, and 263,842 other ranks. Contrast of these figures with the + number of officers and men who took the field in 1914 is indicative of the + magnitude of British aerial effort in the War period. + </p> + <p> + <a name="link2H_4_0022" id="link2H_4_0022"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + XX. THE WAR PERIOD—II + </h2> + <p> + There was when War broke out no realisation on the part of the British + Government of the need for encouraging the enterprise of private builders, + who carried out their work entirely at their-own cost. The importance of a + supply of British-built engines was realised before the War, it is true, + and a competition was held in which a prize of L5,000 was offered for the + best British engine, but this awakening was so late that the R.F.C. took + the field without a single British power plant. Although Germany woke up + equally late to the need for home produced aeroplane engines, the + experience gained in building engines for dirigibles sufficed for the + production of aeroplane power plants. The Mercedes filled all requirements + together with the Benz and the Maybach. There was a 225 horsepower Benz + which was very popular, as were the 100 horse-power and 170 horse-power + Mercedes, the last mentioned fitted to the Aviatik biplane of 1917. The + Uberursel was a copy of the Gnome and supplied the need for rotary + engines. + </p> + <p> + In Great Britain there were a number of aeroplane constructing firms that + had managed to emerge from the lean years 1912-1913 with sufficient + manufacturing plant to give a hand in making up the leeway of construction + when War broke out. Gradually the motor-car firms came in, turning their + body-building departments to plane and fuselage construction, which + enabled them to turn out the complete planes engined and ready for the + field. The coach-building trade soon joined in and came in handy as + propeller makers; big upholstering and furniture firms and scores of + concerns that had never dreamed of engaging in aeroplane construction were + busy on supplying the R.F.C. By 1915 hundreds of different firms were + building aeroplanes and parts; by 1917 the number had increased to over + 1,000, and a capital of over a million pounds for a firm that at the + outbreak of War had employed a score or so of hands was by no means + uncommon. Women and girls came into the work, more especially in plane + construction and covering and doping, though they took their place in the + engine shops and proved successful at acetylene welding and work at the + lathes. It was some time before Britain was able to provide its own + magnetos, for this key industry had been left in the hands of the Germans + up to the outbreak of War, and the 'Bosch' was admittedly supreme—even + now it has never been beaten, and can only be equalled, being as near + perfection as is possible for a magneto. + </p> + <p> + One of the great inventions of the War was the synchronisation of + engine-timing and machine gun, which rendered it possible to fire through + the blades of a propeller without damaging them, though the growing + efficiency of the aeroplane as a whole and of its armament is a thing to + marvel at on looking back and considering what was actually accomplished. + As the efficiency of the aeroplane increased, so anti-aircraft guns and + range-finding were improved. Before the War an aeroplane travelling at + full speed was reckoned perfectly safe at 4,000 feet, but, by the first + month of 1915, the safe height had gone up to 9,000 feet, 7,000 feet being + the limit of rifle and machine gun bullet trajectory; the heavier guns + were not sufficiently mobile to tackle aircraft. At that time, it was + reckoned that effective aerial photography ceased at 6,000 feet, while + bomb-dropping from 7,000-8,000 feet was reckoned uncertain except in the + case of a very large target. The improvement in anti-aircraft devices went + on, and by May of 1916, an aeroplane was not safe under 15,000 feet, while + anti-aircraft shells had fuses capable of being set to over 20,000 feet, + and bombing from 15,000 and 16,000 feet was common. It was not till later + that Allied pilots demonstrated the safety that lies in flying very near + the ground, this owing to the fact that, when flying swiftly at a very low + altitude, the machine is out of sight almost before it can be aimed at. + </p> + <p> + The Battle of the Somme and the clearing of the air preliminary to that + operation brought the fighting aeroplane pure and simple with them. + Formations of fighting planes preceded reconnaissance craft in order to + clear German machines and observation balloons out of the sky and to watch + and keep down any further enemy formations that might attempt to interfere + with Allied observation work. The German reply to this consisted in the + formation of the Flying Circus, of which Captain Baron von Richthofen's + was a good example. Each circus consisted of a large formation of speedy + machines, built specially for fighting and manned by the best of the + German pilots. These were sent to attack at any point along the line where + the Allies had got a decided superiority. + </p> + <p> + The trick flying of pre-war days soon became an everyday matter; Pegoud + astonished the aviation world before the War by first looping the loop, + but, before three years of hostilities had elapsed, looping was part of + the training of practically every pilot, while the spinning nose dive, + originally considered fatal, was mastered, and the tail slide, which + consisted of a machine rising nose upward in the air and falling back on + its tail, became one of the easiest 'stunts' in the pilot's repertoire. + Inherent stability was gradually improved, and, from 1916 onward, + practically every pilot could carry on with his machine-gun or camera and + trust to his machine to fly itself until he was free to attend to it. + There was more than one story of a machine coming safely to earth and + making good landing on its own account with the pilot dead in his + cock-pit. + </p> + <p> + Toward the end of the War, the Independent Air Force was formed as a + branch of the R.A.F. with a view to bombing German bases and devoting its + attention exclusively to work behind the enemy lines. Bombing operations + were undertaken by the R.N.A.S. as early as 1914-1915 against Cuxhaven, + Dusseldorf, and Friedrichshavn, but the supply of material was not + sufficient to render these raids continuous. A separate Brigade, the 8th, + was formed in 1917 to harass the German chemical and iron industries, the + base being in the Nancy area, and this policy was found so fruitful that + the Independent Force was constituted on the 8th June, 1918. The value of + the work accomplished by this force is demonstrated by the fact that the + German High Command recalled twenty fighting squadrons from the Western + front to counter its activities, and, in addition, took troops away from + the fighting line in large numbers for manning anti-aircraft batteries and + searchlights. The German press of the last year of the War is eloquent of + the damage done in manufacturing areas by the Independent Force, which, + had hostilities continued a little longer, would have included Berlin in + its activities. + </p> + <p> + Formation flying was first developed by the Germans, who made use of it in + the daylight raids against England in 1917. Its value was very soon + realised, and the V formation of wild geese was adopted, the leader taking + the point of the V and his squadron following on either side at different + heights. The air currents set up by the leading machines were thus avoided + by those in the rear, while each pilot had a good view of the leader's + bombs, and were able to correct their own aim by the bursts, while the + different heights at which they flew rendered anti-aircraft gun practice + less effective. Further, machines were able to afford mutual protection to + each other and any attacker would be met by machine-gun fire from three or + four machines firing on him from different angles and heights. In the + later formations single-seater fighters flew above the bombers for the + purpose of driving off hostile craft. Formation flying was not fully + developed when the end of the War brought stagnation in place of the rapid + advance in the strategy and tactics of military air work. + </p> + <p> + <a name="link2H_4_0023" id="link2H_4_0023"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + XXI. RECONSTRUCTION + </h2> + <p> + The end of the War brought a pause in which the multitude of aircraft + constructors found themselves faced with the possible complete stagnation + of the industry, since military activities no longer demanded their + services and the prospects of commercial flying were virtually nil. That + great factor in commercial success, cost of plant and upkeep, had received + no consideration whatever in the War period, for armies do not count cost. + The types of machines that had evolved from the War were very fast, very + efficient, and very expensive, although the bombers showed promise of + adaptation to commercial needs, and, so far as other machines were + concerned, America had already proved the possibilities of mail-carrying + by maintaining a mail service even during the War period. + </p> + <p> + A civil aviation department of the Air Ministry was formed in February of + 1919 with a Controller General of Civil Aviation at the head. This was + organised into four branches, one dealing with the survey and preparation + of air routes for the British Empire, one organising meteorological and + wireless telegraphy services, one dealing with the licensing of + aerodromes, machines for passenger or goods carrying and civilian pilots, + and one dealing with publicity and transmission of information generally. + A special Act of Parliament 264 entitled 'The Air Navigation Acts, + 1911-1919,' was passed on February 27th, and commercial flying was + officially permitted from May 1st, 1919. + </p> + <p> + Meanwhile the great event of 1919, the crossing of the Atlantic by air, + was gradually ripening to performance. In addition to the rigid airship, + R.34, eight machines entered for this flight, these being a Short + seaplane, Handley-Page, Martinsyde, Vickers-Vimy, and Sopwith aeroplanes, + and three American flying boats, N.C.1, N.C.3, and N.C.4. The Short + seaplane was the only one of the eight which proposed to make the journey + westward; in flying from England to Ireland, before starting on the long + trip to Newfoundland, it fell into the sea off the coast of Anglesey, and + so far as it was concerned the attempt was abandoned. + </p> + <p> + The first machines to start from the Western end were the three American + seaplanes, which on the morning of May 6th left Trepassy, Newfoundland, on + the 1,380 mile stage to Horta in the Azores. N.C.1 and N.C.3 gave up the + attempt very early, but N.C.4, piloted by Lieut.-Commander Read, U.S.N., + made Horta on May 17th and made a three days' halt. On the 20th the second + stage of the journey to Ponta Delgada, a further 190 miles, was completed + and a second halt of a week was made. On the 27th, the machine left for + Lisbon, 900 miles distant, and completed the journey in a day. On the 30th + a further stage of 340 miles took N.C.4 on to Ferrol, and the next day the + last stage of 420 miles to Plymouth was accomplished. + </p> + <p> + Meanwhile, H. G. Hawker, pilot of the Sopwith biplane, together with + Commander Mackenzie Grieve, R.N., his navigator, found the weather + sufficiently auspicious to set out at 6.48 p.m. On Sunday, May 18th, in + the hope of completing the trip by the direct route before N.C.4 could + reach Plymouth. They set out from Mount Pearl aerodrome, St John's, + Newfoundland, and vanished into space, being given up as lost, as Hamel + was lost immediately before the War in attempting to fly the North Sea. + There was a week of dead silence regarding their fate, but on the + following Sunday morning there was world-wide relief at the news that the + plucky attempt had not ended in disaster, but both aviators had been + picked up by the steamer Mary at 9.30 a.m. on the morning of the 19th, + while still about 750 miles short of the conclusion of their journey. + Engine failure brought them down, and they planed down to the sea close to + the Mary to be picked up; as the vessel was not fitted with wireless, the + news of their rescue could not be communicated until land was reached. An + equivalent of half the L10,000 prize offered by the Daily Mail for the + non-stop flight was presented by the paper in recognition of the very + gallant attempt, and the King conferred the Air Force Cross on both pilot + and navigator. + </p> + <p> + Raynham, pilot of the Martinsyde competing machine, had the bad luck to + crash his craft twice in attempting to start before he got outside the + boundary of the aerodrome. The Handley-Page machine was withdrawn from the + competition, and, attempting to fly to America, was crashed on the way. + </p> + <p> + The first non-stop crossing was made on June 14th-15th in 16 hours 27 + minutes, the speed being just over 117 miles per hour. The machine was a + Vickers-Vimy bomber, engined with two Rolls-Royce Eagle VIII's, piloted by + Captain John Alcock, D.S.C., with Lieut. Arthur Whitten-Brown as + navigator. The journey was reported to be very rough, so much so at times + that Captain Alcock stated that they were flying upside down, and for the + greater part of the time they were out of sight of the sea. Both pilot and + navigator had the honour of knighthood conferred on them at the conclusion + of the journey. + </p> + <p> + Meanwhile, commercial flying opened on May 8th (the official date was May + 1st) with a joy-ride service from Hounslow of Avro training machines. The + enterprise caught on remarkably, and the company extended their activities + to coastal resorts for the holiday season—at Blackpool alone they + took up 10,000 passengers before the service was two months old. Hendon, + beginning passenger flights on the same date, went in for exhibition and + passenger flying, and on June 21st the aerial Derby was won by Captain + Gathergood on an Airco 4R machine with a Napier 450 horse-power 'Lion' + engine; incidentally the speed of 129.3 miles per hour was officially + recognised as constituting the world's record for speed within a closed + circuit. On July 17th a Fiat B.R. biplane with a 700 horse-power engine + landed at Kenley aerodrome after having made a non-stop flight of 1,100 + miles. The maximum speed of this machine was 160 miles per hour, and it + was claimed to be the fastest machine in existence. On August 25th a daily + service between London and Paris was inaugurated by the Aircraft + Manufacturing Company, Limited, who ran a machine each way each day, + starting at 12.30 and due to arrive at 2.45 p.m. The Handley-Page Company + began a similar service in September of 1919, but ran it on alternate days + with machines capable of accommodating ten passengers. The single fare in + each case was fixed at 15 guineas and the parcel rate at 7s. 6d. per + pound. + </p> + <p> + Meanwhile, in Germany, a number of passenger services had been in + operation from the early part of the year; the Berlin-Weimar service was + established on February 5th and Berlin-Hamburg on March 1st, both for mail + and passenger carrying. Berlin-Breslau was soon added, but the first route + opened remained most popular, 538 flights being made between its opening + and the end of April, while for March and April combined, the + Hamburg-Berlin route recorded only 262 flights. All three routes were + operated by a combine of German aeronautical firms entitled the Deutsch + Luft Rederie. The single fare between Hamburg and Berlin was 450 marks, + between Berlin and Breslau 500 marks, and between Berlin and Weimar 450 + marks. Luggage was carried free of charge, but varied according to the + weight of the passenger, since the combined weight of both passenger and + luggage was not allowed to exceed a certain limit. + </p> + <p> + In America commercial flying had begun in May of 1918 with the mail + service between Washington, Philadelphia, and New York, which proved that + mail carrying is a commercial possibility, and also demonstrated the + remarkable reliability of the modern aeroplane by making 102 complete + flights out of a possible total of 104 in November, 1918, at a cost of + 0.777 of a dollar per mile. By March of 1919 the cost per mile had gone up + to 1.28 dollars; the first annual report issued at the end of May showed + an efficiency of 95.6 per cent and the original six aeroplanes and engines + with which the service began were still in regular use. + </p> + <p> + In June of 1919 an American commercial firm chartered an aeroplane for + emergency service owing to a New York harbour strike and found it so + useful that they made it a regular service. The Travellers Company + inaugurated a passenger flying boat service between New York and Atlantic + City on July 25th, the fare, inclusive of 35 lbs. of luggage, being fixed + at L25 each way. + </p> + <p> + Five flights on the American continent up to the end of 1919 are worthy of + note. On December 13th, 1918, Lieut. D. Godoy of the Chilian army left + Santiago, Chili, crossed the Andes at a height of 19,700 feet and landed + at Mendoza, the capital of the wine-growing province of Argentina. On + April 19th, 1919, Captain E. F. White made the first non-stop flight + between New York and Chicago in 6 hours 50 minutes on a D.H.4 machine + driven by a twelve-cylinder Liberty engine. Early in August Major + Schroeder, piloting a French Lepere machine flying at a height of 18,400 + feet, reached a speed of 137 miles per hour with a Liberty motor fitted + with a super-charger. Toward the end of August, Rex Marshall, on a + Thomas-Morse biplane, starting from a height of 17,000 feet, made a glide + of 35 miles with his engine cut off, restarting it when at a height of 600 + feet above the ground. About a month later R. Rohlfe, piloting a Curtiss + triplane, broke the height record by reaching 34,610 feet. + </p> + <p> + <a name="link2H_4_0024" id="link2H_4_0024"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + XXII. 1919-20 + </h2> + <p> + Into the later months of 1919 comes the flight by Captain Ross-Smith from + England to Australia and the attempt to make the Cape to Cairo voyage by + air. The Australian Government had offered a prize of L10,000 for the + first flight from England to Australia in a British machine, the flight to + be accomplished in 720 consecutive hours. Ross-Smith, with his brother, + Lieut. Keith Macpherson Smith, and two mechanics, left Hounslow in a + Vickers-Vimy bomber with Rolls-Royce engine on November 12th and arrived + at Port Darwin, North Australia, on the 10th December, having completed + the flight in 27 days 20 hours 20 minutes, thus having 51 hours 40 minutes + to spare out of the 720 allotted hours. + </p> + <p> + Early in 1920 came a series of attempts at completing the journey by air + between Cairo and the Cape. Out of four competitors Colonel Van Ryneveld + came nearest to making the journey successfully, leaving England on a + standard Vickers-Vimy bomber with Rolls-Royce engines, identical in design + with the machine used by Captain Ross-Smith on the England to Australia + flight. A second Vickers-Vimy was financed by the Times newspaper and a + third flight was undertaken with a Handley-Page machine under the auspices + of the Daily Telegraph. The Air Ministry had already prepared the route by + means of three survey parties which cleared the aerodromes and landing + grounds, dividing their journey into stages of 200 miles or less. Not one + of the competitors completed the course, but in both this and Ross-Smith's + flight valuable data was gained in respect of reliability of machines and + engines, together with a mass of meteorological information. + </p> + <p> + The Handley-Page Company announced in the early months of 1920 that they + had perfected a new design of wing which brought about a twenty to forty + per cent improvement in lift rate in the year. When the nature of the + design was made public, it was seen to consist of a division of the wing + into small sections, each with its separate lift. A few days later, + Fokker, the Dutch inventor, announced the construction of a machine in + which all external bracing wires are obviated, the wings being of a very + deep section and self-supporting. The value of these two inventions + remains to be seen so far as commercial flying is concerned. + </p> + <p> + The value of air work in war, especially so far as the Colonial campaigns + in which British troops are constantly being engaged is in question, was + very thoroughly demonstrated in a report issued early in 1920 with + reference to the successful termination of the Somaliland campaign through + the intervention of the Royal Air Force, which between January 21st and + the 31st practically destroyed the Dervish force under the Mullah, which + had been a thorn in the side of Britain since 1907. Bombs and machine-guns + did the work, destroying fortifications and bringing about the surrender + of all the Mullah's following, with the exception of about seventy who + made their escape. + </p> + <p> + Certain records both in construction and performance had characterised the + post-war years, though as design advances and comes nearer to perfection, + it is obvious that records must get fewer and farther between. The record + aeroplane as regards size at the time of its construction was the Tarrant + triplane, which made its first—and last—flight on May 28th, + 1919. The total loaded weight was 30 tons, and the machine was fitted with + six 400 horse-power engines; almost immediately after the trial flight + began, the machine pitched forward on its nose and was wrecked, causing + fatal injuries to Captains Dunn and Rawlings, who were aboard the machine. + A second accident of similar character was that which befell the giant + seaplane known as the Felixstowe Fury, in a trial flight. This latter + machine was intended to be flown to Australia, but was crashed over the + water. + </p> + <p> + On May 4th, 1920, a British record for flight duration and useful load was + established by a commercial type Handley-Page biplane, which, carrying a + load of 3,690 lbs., rose to a height of 13,999 feet and remained in the + air for 1 hour 20 minutes. On May 27th the French pilot, Fronval, flying + at Villacoublay in a Morane-Saulnier type of biplane with Le Rhone motor, + put up an extraordinary type of record by looping the loop 962 times in 3 + hours 52 minutes 10 seconds. Another record of the year of similar nature + was that of two French fliers, Boussotrot and Bernard, who achieved a + continuous flight of 24 hours 19 minutes 7 seconds, beating the pre-war + record of 21 hours 48 3/4 seconds set up by the German pilot, Landemann. + Both these records are likely to stand, being in the nature of freaks, + which demonstrate little beyond the reliability of the machine and the + capacity for endurance on the part of its pilots. + </p> + <p> + Meanwhile, on February 14th, Lieuts. Masiero and Ferrarin left Rome on + S.V.A. Ansaldo V. machines fitted with 220 horse-power S.V.A. motors. On + May 30th they arrived at Tokio, having flown by way of Bagdad, Karachi, + Canton, Pekin, and Osaka. Several other competitors started, two of whom + were shot down by Arabs in Mesopotamia. + </p> + <p> + Considered in a general way, the first two years after the termination of + the Great European War form a period of transition in which the commercial + type of aeroplane was gradually evolved from the fighting machine which + was perfected in the four preceding years. There was about this period no + sense of finality, but it was as experimental, in its own way, as were the + years of progressing design which preceded the war period. Such commercial + schemes as were inaugurated call for no more note than has been given + here; they have been experimental, and, with the possible exception of the + United States Government mail service, have not been planned and executed + on a sufficiently large scale to furnish reliable data on which to + forecast the prospects of commercial aviation. And there is a school + rapidly growing up which asserts that the day of aeroplanes is nearly + over. The construction of the giant airships of to-day and the successful + return flight of R34 across the Atlantic seem to point to the eventual + triumph, in spite of its disadvantages, of the dirigible airship. + </p> + <p> + This is a hard saying for such of the aeroplane industry as survived the + War period and consolidated itself, and it is but the saying of a section + which bases its belief on the fact that, as was noted in the very early + years of the century, the aeroplane is primarily a war machine. Moreover, + the experience of the War period tended to discredit the dirigible, since, + before the introduction of helium gas, the inflammability of its buoyant + factor placed it at an immense disadvantage beside the machine dependent + on the atmosphere itself for its lift. + </p> + <p> + As life runs to-day, it is a long time since Kipling wrote his story of + the airways of a future world and thrust out a prophecy that the bulk of + the world's air traffic would be carried by gas-bag vessels. If the school + which inclines to belief in the dirigible is right in its belief, as it + well may be, then the foresight was uncannily correct, not only in the + matter of the main assumption, but in the detail with which the writer + embroidered it. + </p> + <p> + On the constructional side, the history of the aeroplane is still so much + in the making that any attempt at a critical history would be unwise, and + it is possible only to record fact, leaving it to the future for judgment + to be passed. But, in a general way, criticism may be advanced with regard + to the place that aeronautics takes in civilisation. In the past hundred + years, the world has made miraculously rapid strides materially, but moral + development has not kept abreast. Conception of the responsibilities of + humanity remains virtually in a position of a hundred years ago; given a + higher conception of life and its responsibilities, the aeroplane becomes + the crowning achievement of that long series which James Watt inaugurated, + the last step in intercommunication, the chain with which all nations are + bound in a growing prosperity, surely based on moral wellbeing. Without + such conception of the duties as well as the rights of life, this last + achievement of science may yet prove the weapon that shall end + civilisation as men know it to-day, and bring this ultra-material age to a + phase of ruin on which saner people can build a world more reasonable and + less given to groping after purely material advancement. + </p> + <p> + <a name="link2H_PART2" id="link2H_PART2"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + PART II. 1903-1920: PROGRESS IN DESIGN + </h2> + <h3> + By Lieut.-Col. W. Lockwood Marsh + </h3> + <p> + <a name="link2H_4_0026" id="link2H_4_0026"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + I. THE BEGINNINGS + </h2> + <p> + Although the first actual flight of an aeroplane was made by the Wrights + on December 17th 1903, it is necessary, in considering the progress of + design between that period and the present day, to go back to the earlier + days of their experiments with 'gliders,' which show the alterations in + design made by them in their step-bystep progress to a flying machine + proper, and give a clear idea of the stage at which they had arrived in + the art of aeroplane design at the time of their first flights. + </p> + <p> + They started by carefully surveying the work of previous experimenters, + such as Lilienthal and Chanute, and from the lesson of some of the + failures of these pioneers evolved certain new principles which were + embodied in their first glider, built in 1900. In the first place, instead + of relying upon the shifting of the operator's body to obtain balance, + which had proved too slow to be reliable, they fitted in front of the main + supporting surfaces what we now call an 'elevator,' which could be flexed, + to control the longitudinal balance, from where the operator lay prone + upon the main supporting surfaces. The second main innovation which they + incorporated in this first glider, and the principle of which is still + used in every aeroplane in existence, was the attainment of lateral + balance by warping the extremities of the main planes. The effect of + warping or pulling down the extremity of the wing on one side was to + increase its lift and so cause that side to rise. In the first two gliders + this control was also used for steering to right and left. Both these + methods of control were novel for other than model work, as previous + experimenters, such as Lilienthal and Pilcher, had relied entirely upon + moving the legs or shifting the position of the body to control the + longitudinal and lateral motions of their gliders. For the main supporting + surfaces of the glider the biplane system of Chanute's gliders was adopted + with certain modifications, while the curve of the wings was founded upon + the calculations of Lilienthal as to wind pressure and consequent lift of + the plane. + </p> + <p> + This first glider was tested on the Kill Devil Hill sand-hills in North + Carolina in the summer of 1900 and proved at any rate the correctness of + the principles of the front elevator and warping wings, though its + designers were puzzled by the fact that the lift was less than they + expected; whilst the 'drag'(as we call it), or resistance, was also + considerably lower than their predictions. The 1901 machine was, in + consequence, nearly doubled in area—the lifting surface being + increased from 165 to 308 square feet—the first trial taking place + on July 27th, 1901, again at Kill Devil Hill. It immediately appeared that + something was wrong, as the machine dived straight to the ground, and it + was only after the operator's position had been moved nearly a foot back + from what had been calculated as the correct position that the machine + would glide—and even then the elevator had to be used far more + strongly than in the previous year's glider. After a good deal of thought + the apparent solution of the trouble was finally found. + </p> + <p> + This consisted in the fact that with curved surfaces, while at large + angles the centre of pressure moves forward as the angle decreases, when a + certain limit of angle is reached it travels suddenly backwards and causes + the machine to dive. The Wrights had known of this tendency from + Lilienthal's researches, but had imagined that the phenomenon would + disappear if they used a fairly lightly cambered—or curved—surface + with a very abrupt curve at the front. Having discovered what appeared to + be the cause they surmounted the difficulty by 'trussing down' the camber + of the wings, with the result that they at once got back to the old + conditions of the previous year and could control the machine readily with + small movements of the elevator, even being able to follow undulations in + the ground. They still found, however, that the lift was not as great as + it should have been; while the drag remained, as in the previous glider, + surprisingly small. This threw doubt on previous figures as to wind + resistance and pressure on curved surfaces; but at the same time confirmed + (and this was a most important result) Lilienthal's previously questioned + theory that at small angles the pressure on a curved surface instead of + being normal, or at right angles to, the chord is in fact inclined in + front of the perpendicular. The result of this is that the pressure + actually tends to draw the machine forward into the wind—hence the + small amount of drag, which had puzzled Wilbur and Orville Wright. + </p> + <p> + Another lesson which was learnt from these first two years of experiment, + was that where, as in a biplane, two surfaces are superposed one above the + other, each of them has somewhat less lift than it would have if used + alone. The experimenters were also still in doubt as to the efficiency of + the warping method of controlling the lateral balance as it gave rise to + certain phenomena which puzzled them, the machine turning towards the wing + having the greater angle, which seemed also to touch the ground first, + contrary to their expectations. Accordingly, on returning to Dayton + towards the end of 1901, they set themselves to solve the various problems + which had appeared and started on a lengthy series of experiments to check + the previous figures as to wind resistance and lift of curved surfaces, + besides setting themselves to grapple with the difficulty of lateral + control. They accordingly constructed for themselves at their home in + Dayton a wind tunnel 16 inches square by 6 feet long in which they + measured the lift and 'drag' of more than two hundred miniature wings. In + the course of these tests they for the first time produced comparative + results of the lift of oblong and square surfaces, with the result that + they re-discovered the importance of 'aspect ratio'—the ratio of + length to breadth of planes. As a result, in the next year's glider the + aspect ration of the wings was increased from the three to one of the + earliest model to about six to one, which is approximately the same as + that used in the machines of to-day. Further than that, they discussed the + question of lateral stability, and came to the conclusion that the cause + of the trouble was that the effect of warping down one wing was to + increase the resistance of, and consequently slow down, that wing to such + an extent that its lift was reduced sufficiently to wipe out the + anticipated increase in lift resulting from the warping. From this they + deduced that if the speed of the warped wing could be controlled the + advantage of increasing the angle by warping could be utilised as they + originally intended. They therefore decided to fit a vertical fin at the + rear which, if the machine attempted to turn, would be exposed more and + more to the wind and so stop the turning motion by offering increased + resistance. + </p> + <p> + As a result of this laboratory research work the third Wright glider, + which was taken to Kill Devil Hill in September, 1902, was far more + efficient aerodynamically than either of its two predecessors, and was + fitted with a fixed vertical fin at the rear in addition to the movable + elevator in front. According to Mr Griffith Brewer,[*] this third glider + contained 305 square feet of surface; though there may possibly be a + mistake here, as he states[**] the surface of the previous year's glider + to have been only 290 square feet, whereas Wilbur Wright himself[***] + states it to have been 308 square feet. The matter is not, perhaps, save + historically, of much importance, except that the gliders are believed to + have been progressively larger, and therefore if we accept Wilbur Wright's + own figure of the surface of the second glider, the third must have had a + greater area than that given by Mr Griffith Brewer. Unfortunately, no + evidence of the Wright Brothers themselves on this point is available. + </p> + <p> + [*] Fourth Wilbur Wright Memorial Lecture, Aeronautical Journal, Vol. XX, + No. 79, page 75. + </p> + <p> + [**] Ibid. page 73. + </p> + <p> + [***] Ibid. pp. 91 and 102. + </p> + <p> + The first glide of the 1902, season was made on September 17th of that + year, and the new machine at once showed itself an improvement on its + predecessors, though subsequent trials showed that the difficulty of + lateral balance had not been entirely overcome. It was decided, therefore, + to turn the vertical fin at the rear into a rudder by making it movable. + At the same time it was realised that there was a definite relation + between lateral balance and directional control, and the rudder controls + and wing-warping wires were accordingly connected This ended the pioneer + gliding experiments of Wilbur and Orville Wright—though further + glides were made in subsequent years—as the following year, 1903, + saw the first power-driven machine leave the ground. + </p> + <p> + To recapitulate—in the course of these original experiments the + Wrights confirmed Lilienthal's theory of the reversal of the centre of + pressure on cambered surfaces at small angles of incidence: they confirmed + the importance of high aspect ratio in respect to lift: they had evolved + new and more accurate tables of lift and pressure on cambered surfaces: + they were the first to use a movable horizontal elevator for controlling + height: they were the first to adjust the wings to different angles of + incidence to maintain lateral balance: and they were the first to use the + movable rudder and adjustable wings in combination. + </p> + <p> + They now considered that they had gone far enough to justify them in + building a power-driven 'flier,' as they called their first aeroplane. + They could find no suitable engine and so proceeded to build for + themselves an internal combustion engine, which was designed to give 8 + horse-power, but when completed actually developed about 12-15 horse-power + and weighed 240 lbs. The complete machine weighed about 750 lbs. Further + details of the first Wright aeroplane are difficult to obtain, and even + those here given should be received with some caution. The first flight + was made on December 17th 1903, and lasted 12 seconds. Others followed + immediately, and the fourth lasted 59 seconds, a distance of 852 feet + being covered against a 20-mile wind. + </p> + <p> + The following year they transferred operations to a field outside Dayton, + Ohio (their home), and there they flew a somewhat larger and heavier + machine with which on September 20th 1904, they completed the first circle + in the air. In this machine for the first time the pilot had a seat; all + the previous experiments having been carried out with the operator lying + prone on the lower wing. This was followed next year by another still + larger machine, and on it they carried out many flights. During the course + of these flights they satisfied themselves as to the cause of a phenomenon + which had puzzled them during the previous year and caused them to fear + that they had not solved the problem of lateral control. They found that + on occasions—always when on a turn—the machine began to slide + down towards the ground and that no amount of warping could stop it. + Finally it was found that if the nose of the machine was tilted down a + recovery could be effected; from which they concluded that what actually + happened was that the machine, 'owing to the increased load caused by + centrifugal force,' had insufficient power to maintain itself in the air + and therefore lost speed until a point was reached at which the controls + became inoperative. In other words, this was the first experience of + 'stalling on a turn,' which is a danger against which all embryo pilots + have to guard in the early stages of their training. + </p> + <p> + The 1905 machine was, like its predecessors, a biplane with a biplane + elevator in front and a double vertical rudder in rear. The span was 40 + feet, the chord of the wings being 6 feet and the gap between them about + the same. The total area was about 600 square feet which supported a total + weight of 925 lbs.; while the motor was 12 to 15 horse-power driving two + propellers on each side behind the main planes through chains and giving + the machine a speed of about 30 m.p.h. one of these chains was crossed so + that the propellers revolved in opposite directions to avoid the torque + which it was feared would be set up if they both revolved the same way. + The machine was not fitted with a wheeled undercarriage but was carried on + two skids, which also acted as outriggers to carry the elevator. + Consequently, a mechanical method of launching had to be evolved and the + machine received initial velocity from a rail, along which it was drawn by + the impetus provided by the falling of a weight from a wooden tower or + 'pylon.' As a result of this the Wright aeroplane in its original form had + to be taken back to its starting rail after each flight, and could not + restart from the point of alighting. Perhaps, in comparison with French + machines of more or less contemporary date (evolved on independent lines + in ignorance of the Americans' work), the chief feature of the Wright + biplane of 1905 was that it relied entirely upon the skill of the operator + for its stability; whereas in France some attempt was being made, although + perhaps not very successfully, to make the machine automatically stable + laterally. The performance of the Wrights in carrying a loading of some 60 + lbs. per horse-power is one which should not be overlooked. The wing + loading was about 1 1/2 lbs. per square foot. + </p> + <p> + About the same time that the Wrights were carrying out their power-driven + experiments, a band of pioneers was quite independently beginning to + approach success in France. In practically every case, however, they + started from a somewhat different standpoint and took as their basic idea + the cellular (or box) kite. This form of kite, consisting of two + superposed surfaces connected at each end by a vertical panel or curtain + of fabric, had proved extremely successful for man-carrying purposes, and, + therefore, it was little wonder that several minds conceived the idea of + attempting to fly by fitting a series of box-kites with an engine. The + first to achieve success was M. Santos-Dumont, the famous Brazilian + pioneer-designer of airships, who, on November 12th, 1906, made several + flights, the last of which covered a little over 700 feet. Santos-Dumont's + machine consisted essentially of two box-kites, forming the main wings, + one on each side of the body, in which the pilot stood, and at the front + extremity of which was another movable box-kite to act as elevator and + rudder. The curtains at the ends were intended to give lateral stability, + which was further ensured by setting the wings slightly inclined upwards + from the centre, so that when seen from the front they formed a wide V. + This feature is still to be found in many aeroplanes to-day and has come + to be known as the 'dihedral.' The motor was at first of 24 horse-power, + for which later a 50 horse-power Antoinette engine was substituted; whilst + a three-wheeled undercarriage was provided, so that the machine could + start without external mechanical aid. The machine was constructed of + bamboo and steel, the weight being as low as 352 lbs. The span was 40 + feet, the length being 33 feet, with a total surface of main planes of 860 + square feet. It will thus be seen—for comparison with the Wright + machine—that the weight per horse-power (with the 50 horse-power + engine) was only 7 lbs., while the wing loading was equally low at 1/2 lb. + per square foot. + </p> + <p> + The main features of the Santos-Dumont machine were the box-kite form of + construction, with a dihedral angle on the main planes, and the forward + elevator which could be moved in any direction and therefore acted in the + same way as the rudder at the rear of the Wright biplane. It had a single + propeller revolving in the centre behind the wings and was fitted with an + undercarriage incorporated in the machine. + </p> + <p> + The other chief French experimenters at this period were the Voisin + Freres, whose first two machines—identical in form—were sold + to Delagrange and H. Farman, which has sometimes caused confusion, the two + purchasers being credited with the design they bought. The Voisins, like + the Wrights, based their designs largely on the experimental work of + Lilienthal, Langley, Chanute, and others, though they also carried out + tests on the lifting properties of aerofoils in a wind tunnel of their + own. Their first machines, like those of Santos-Dumont, showed the effects + of experimenting with box-kites, some of which they had built for M. + Ernest Archdeacon in 1904. In their case the machine, which was again a + biplane, had, like both the others previously mentioned, an elevator in + front—though in this case of monoplane form—and, as in the + Wright, a rudder was fitted in rear of the main planes. The Voisins, + however, fitted a fixed biplane horizontal 'tail'—in an effort to + obtain a measure of automatic longitudinal stability—between the two + surfaces of which the single rudder worked. For lateral stability they + depended entirely on end curtains between the upper and lower surfaces of + both the main planes and biplane tail surfaces. They, like Santos-Dumont, + fitted a wheeled undercarriage, so that the machine was self-contained. + The Voisin machine, then, was intended to be automatically stable in both + senses; whereas the Wrights deliberately produced a machine which was + entirely dependent upon the pilot's skill for its stability. The + dimensions of the Voisin may be given for comparative purposes, and were + as follows: Span 33 feet with a chord (width from back to front) of main + planes of 6 1/2 feet, giving a total area of 430 square feet. The 50 + horse-power Antoinette engine, which was enclosed in the body (or 'nacelle + ') in the front of which the pilot sat, drove a propeller behind, + revolving between the outriggers carrying the tail. The total weight, + including Farman as pilot, is given as 1,540 lbs., so that the machine was + much heavier than either of the others; the weight per horse-power being + midway between the Santos-Dumont and the Wright at 31 lbs. per square + foot, while the wing loading was considerably greater than either at 3 1/2 + lbs. per square foot. The Voisin machine was experimented with by Farman + and Delagrange from about June 1907 onwards, and was in the subsequent + years developed by Farman; and right up to the commencement of the War + upheld the principles of the box-kite method of construction for training + purposes. The chief modification of the original design was the addition + of flaps (or ailerons) at the rear extremities of the main planes to give + lateral control, in a manner analogous to the wing-warping method invented + by the Wrights, as a result of which the end curtains between the planes + were abolished. An additional elevator was fitted at the rear of the fixed + biplane tail, which eventually led to the discarding of the front elevator + altogether. During the same period the Wright machine came into line with + the others by the fitting of a wheeled undercarriage integral with the + machine. A fixed horizontal tail was also added to the rear rudder, to + which a movable elevator was later attached; and, finally, the front + elevator was done away with. It will thus be seen that having started from + the very different standpoints of automatic stability and complete control + by the pilot, the Voisin (as developed in the Farman) and Wright machines, + through gradual evolution finally resulted in aeroplanes of similar + characteristics embodying a modicum of both features. + </p> + <p> + Before proceeding to the next stage of progress mention should be made of + the experimental work of Captain Ferber in France. This officer carried + out a large number of experiments with gliders contemporarily with the + Wrights, adopting—like them—the Chanute biplane principle. He + adopted the front elevator from the Wrights, but immediately went a step + farther by also fitting a fixed tail in rear, which did not become a + feature of the Wright machine until some seven or eight years later. He + built and appeared to have flown a machine fitted with a motor in 1905, + and was commissioned to go to America by the French War Office on a secret + mission to the Wrights. Unfortunately, no complete account of his + experiments appears to exist, though it can be said that his work was at + least as important as that of any of the other pioneers mentioned. + </p> + <p> + <a name="link2H_4_0027" id="link2H_4_0027"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + II. MULTIPLICITY OF IDEAS + </h2> + <p> + In a review of progress such as this, it is obviously impossible, when a + certain stage of development has been reached, owing to the very + multiplicity of experimenters, to continue dealing in anything approaching + detail with all the different types of machines; and it is proposed, + therefore, from this point to deal only with tendencies, and to mention + individuals merely as examples of a class of thought rather than as + personalities, as it is often difficult fairly to allocate the + responsibility for any particular innovation. + </p> + <p> + During 1907 and 1908 a new type of machine, in the monoplane, began to + appear from the workshops of Louis Bleriot, Robert Esnault-Pelterie, and + others, which was destined to give rise to long and bitter controversies + on the relative advantages of the two types, into which it is not proposed + to enter here; though the rumblings of the conflict are still to be heard + by discerning ears. Bleriot's early monoplanes had certain new features, + such as the location of the pilot, and in some cases the engine, below the + wing; but in general his monoplanes, particularly the famous No. XI on + which the first Channel crossing was made on July 25th, 1909, embodied the + main principles of the Wright and Voisin types, except that the propeller + was in front of instead of behind the supporting surfaces, and was, + therefore, what is called a 'tractor' in place of the then more + conventional 'pusher.' Bleriot aimed at lateral balance by having the tip + of each wing pivoted, though he soon fell into line with the Wrights and + adopted the warping system. The main features of the design of + Esnault-Pelterie's monoplane was the inverted dihedral (or kathedral as + this was called in Mr S. F. Cody's British Army Biplane of 1907) on the + wings, whereby the tips were considerably lower than the roots at the + body. This was designed to give automatic lateral stability, but, here + again, conventional practice was soon adopted and the R.E.P. monoplanes, + which became well-known in this country through their adoption in the + early days by Messrs Vickers, were of the ordinary monoplane design, + consisting of a tractor propeller with wire-stayed wings, the pilot being + in an enclosed fuselage containing the engine in front and carrying at its + rear extremity fixed horizontal and vertical surfaces combined with + movable elevators and rudder. Constructionally, the R.E.P. monoplane was + of extreme interest as the body was constructed of steel. The Antoinette + monoplane, so ably flown by Latham, was another very famous machine of the + 1909-1910 period, though its performance were frequently marred by engine + failure; which was indeed the bugbear of all these early experimenters, + and it is difficult to say, after this lapse of time, how far in many + cases the failures which occurred, both in performances and even in the + actual ability to rise from the ground, were due to defects in design or + merely faults in the primitive engines available. The Antoinette aroused + admiration chiefly through its graceful, birdlike lines, which have + probably never been equalled; but its chief interest for our present + purpose lies in the novel method of wing-staying which was employed. + Contemporary monoplanes practically all had their wings stayed by wires to + a post in the centre above the fuselage, and, usually, to the + undercarriage below. In the Antoinette, however, a king post was + introduced half-way along the wing, from which wires were carried to the + ends of the wings and the body. This was intended to give increased + strength and permitted of a greater wing-spread and consequently improved + aspect ratio. The same system of construction was adopted in the British + Martinsyde monoplanes of two or three years later. + </p> + <p> + This period also saw the production of the first triplane, which was built + by A. V. Roe in England and was fitted with a J.A.P. engine of only 9 + horse-power—an amazing performance which remains to this day + unequalled. Mr Roe's triplane was chiefly interesting otherwise for the + method of maintaining longitudinal control, which was achieved by pivoting + the whole of the three main planes so that their angle of incidence could + be altered. This was the direct converse of the universal practice of + elevating by means of a subsidiary surface either in front or rear of the + main planes. + </p> + <p> + Recollection of the various flying meetings and exhibitions which one + attended during the years from 1909 to 1911, or even 1912 are chiefly + notable for the fact that the first thought on seeing any new type of + machine was not as to what its 'performance'—in speed, lift, or what + not—would be; but speculation as to whether it would leave the + ground at all when eventually tried. This is perhaps the best indication + of the outstanding characteristic of that interim period between the time + of the first actual flights and the later period, commencing about 1912, + when ideas had become settled and it was at last becoming possible to + forecast on the drawing-board the performance of the completed machine in + the air. Without going into details, for which there is no space here, it + is difficult to convey the correct impression of the chaotic state which + existed as to even the elementary principles of aeroplane design. All the + exhibitions contained large numbers—one had almost written a + majority—of machines which embodied the most unusual features and + which never could, and in practice never did, leave the ground. At the + same time, there were few who were sufficiently hardy to say certainly + that this or that innovation was wrong; and consequently dozens of + inventors in every country were conducting isolated experiments on both + good and bad lines. All kinds of devices, mechanical and otherwise, were + claimed as the solution of the problem of stability, and there was even + controversy as to whether any measure of stability was not undesirable; + one school maintaining that the only safety lay in the pilot having the + sole say in the attitude of the machine at any given moment, and fearing + danger from the machine having any mind of its own, so to speak. There + was, as in most controversies, some right on both sides, and when we come + to consider the more settled period from 1912 to the outbreak of the War + in 1914 we shall find how a compromise was gradually effected. + </p> + <p> + At the same time, however, though it was at the time difficult to pick + out, there was very real progress being made, and, though a number of + 'freak' machines fell out by the wayside, the pioneer designers of those + days learnt by a process of trial and error the right principles to follow + and gradually succeeded in getting their ideas crystallised. + </p> + <p> + In connection with stability mention must be made of a machine which was + evolved in the utmost secrecy by Mr J. W. Dunne in a remote part of + Scotland under subsidy from the War office. This type, which was + constructed in both monoplane and biplane form, showed that it was in fact + possible in 1910 and 1911 to design an aeroplane which could definitely be + left to fly itself in the air. One of the Dunne machines was, for example + flown from Farnborough to Salisbury Plain without any control other than + the rudder being touched; and on another occasion it flew a complete + circle with all controls locked automatically assuming the correct bank + for the radius of turn. The peculiar form of wing used, the camber of + which varied from the root to the tip, gave rise however, to a certain + loss in efficiency, and there was also a difficulty in the pilot assuming + adequate control when desired. Other machines designed to be stable—such + as the German Etrich and the British Weiss gliders and Handley-Page + monoplanes—were based on the analogy of a wing attached to a certain + seed found in Nature (the 'Zanonia' leaf), on the righting effect of + back-sloped wings combined with upturned (or 'negative') tips. Generally + speaking, however, the machines of the 1909-1912 period relied for what + automatic stability they had on the principle of the dihedral angle, or + flat V, both longitudinally and laterally. Longitudinally this was + obtained by setting the tail at a slightly smaller angle than the main + planes. + </p> + <p> + The question of reducing the resistance by adopting 'stream-line' forms, + along which the air could flow uninterruptedly without the formation of + eddies, was not at first properly realised, though credit should be given + to Edouard Nieuport, who in 1909 produced a monoplane with a very large + body which almost completely enclosed the pilot and made the machine very + fast, for those days, with low horse-power. On one of these machines C. T. + Weyman won the Gordon-Bennett Cup for America in 1911 and another put up a + fine performance in the same race with only a 30 horse-power engine. The + subject, was however, early taken up by the British Advisory Committee for + Aeronautics, which was established by the Government in 1909, and + designers began to realise the importance of streamline struts and + fuselages towards the end of this transition period. These efforts were at + first not always successful and showed at times a lack of understanding of + the problems involved, but there was a very marked improvement during the + year 1912. At the Paris Aero Salon held early in that year there was a + notable variety of ideas on the subject; whereas by the time of the one + held in October designs had considerably settled down, more than one + exhibitor showing what were called 'monocoque' fuselages completely + circular in shape and having very low resistance, while the same show saw + the introduction of rotating cowls over the propeller bosses, or + 'spinners,' as they came to be called during the War. A particularly fine + example of stream-lining was to be found in the Deperdussin monoplane on + which Vedrines won back the Gordon-Bennett Aviation Cup from America at a + speed of 105.5 m.p.h.—a considerable improvement on the 78 m.p.h. of + the preceding year, which was by no means accounted for by the mere + increase in engine power from 100 horse-power to 140 horse-power. This + machine was the first in which the refinement of 'stream-lining' the + pilot's head, which became a feature of subsequent racing machines, was + introduced. This consisted of a circular padded excresence above the + cockpit immediately behind the pilot's head, which gradually tapered off + into the top surface of the fuselage. The object was to give the air an + uninterrupted flow instead of allowing it to be broken up into eddies + behind the head of the pilot, and it also provided a support against the + enormous wind-pressure encountered. This true stream-line form of fuselage + owed its introduction to the Paulhan-Tatin 'Torpille' monoplane of the + Paris Salon of early 1917. Altogether the end of the year 1912 began to + see the disappearance of 'freak' machines with all sorts of original ideas + for the increase of stability and performance. Designs had by then + gradually become to a considerable extent standardised, and it had become + unusual to find a machine built which would fail to fly. The Gnome engine + held the field owing to its advantages, as the first of the rotary type, + in lightness and ease of fitting into the nose of a fuselage. The majority + of machines were tractors (propeller in front) although a preference, + which died down subsequently, was still shown for the monoplane over the + biplane. This year also saw a great increase in the number of seaplanes, + although the 'flying boat' type had only appeared at intervals and the + vast majority were of the ordinary aeroplane type fitted with floats in + place of the land undercarriage; which type was at that time commonly + called 'hydro-aeroplane.' The usual horse power was 50—that of the + smallest Gnome engine—although engines of 100 to 140 horse-power + were also fitted occasionally. The average weight per horse-power varied + from 18 to 25 lbs., while the wing-loading was usually in the + neighbourhood of 5 to 6 lbs. per square foot. The average speed ranged + from 65-75 miles per hour. + </p> + <p> + <a name="link2H_4_0028" id="link2H_4_0028"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + III. PROGRESS ON STANDARDISED LINES + </h2> + <p> + In the last section an attempt has been made to show how, during what was + from the design standpoint perhaps the most critical period, order + gradually became evident out of chaos, ill-considered ideas dropped out + through failure to make good, and, though there was still plenty of room + for improvement in details, the bulk of the aeroplanes showed a general + similarity in form and conception. There was still a great deal to be + learnt in finding the best form of wing section, and performances were + still low; but it had become definitely possible to say that flying had + emerged from the chrysalis stage and had become a science. The period + which now began was one of scientific development and improvement—in + performance, manoeuvrability, and general airworthiness and stability. + </p> + <p> + The British Military Aeroplane Competition held in the summer of 1912 had + done much to show the requirements in design by giving possibly the first + opportunity for a definite comparison of the performance of different + machines as measured by impartial observers on standard lines—albeit + the methods of measuring were crude. These showed that a high speed—for + those days—of 75 miles an hour or so was attended by disadvantages + in the form of an equally fast low speed, of 50 miles per hour or more, + and generally may be said to have given designers an idea what to aim for + and in what direction improvements were required. In fact, the most + noticeable point perhaps of the machines of this time was the marked + manner in which a machine that was good in one respect would be found to + be wanting in others. It had not yet been possible to combine several + desirable attributes in one machine. The nearest approach to this was + perhaps to be found in the much discussed Government B.E.2 machine, which + was produced from the Royal Aircraft Factory at Farnborough, in the summer + of 1912. Though considerably criticized from many points of view it was + perhaps the nearest approach to a machine of all-round efficiency that had + up to that date appeared. The climbing rate, which subsequently proved so + important for military purposes, was still low, seldom, if ever, exceeding + 400 feet per minute; while gliding angles (ratio of descent to forward + travel over the ground with engine stopped) little exceeded 1 in 8. + </p> + <p> + The year 1912 and 1913 saw the subsequently all-conquering tractor biplane + begin to come into its own. This type, which probably originated in + England, and at any rate attained to its greatest excellence prior to the + War from the drawing offices of the Avro Bristol and Sopwith firms, dealt + a blow at the monoplane from which the latter never recovered. + </p> + <p> + The two-seater tractor biplane produced by Sopwith and piloted by H. G. + Hawker, showed that it was possible to produce a biplane with at least + equal speed to the best monoplanes, whilst having the advantage of greater + strength and lower landing speeds. The Sopwith machine had a top speed of + over 80 miles an hour while landing as slowly as little more than 30 miles + an hour; and also proved that it was possible to carry 3 passengers with + fuel for 4 hours' flight with a motive power of only 80 horse-power. This + increase in efficiency was due to careful attention to detail in every + part, improved wing sections, clean fuselage-lines, and simplified + undercarriages. At the same time, in the early part of 1913 a tendency + manifested itself towards the four-wheeled undercarriage, a pair of + smaller wheels being added in front of the main wheels to prevent + overturning while running on the ground; and several designs of + oleo-pneumatic and steel-spring undercarriages were produced in place of + the rubber shock-absorber type which had up till then been almost + universal. + </p> + <p> + These two statements as to undercarriage designs may appear to be + contradictory, but in reality they do not conflict as they both showed a + greater attention to the importance of good springing, combined with a + desire to avoid complication and a mass of struts and wires which + increased head resistance. + </p> + <p> + The Olympia Aero Show of March, 1913, also produced a machine which, + although the type was not destined to prove the best for the purpose for + which it was designed, was of interest as being the first to be designed + specially for war purposes. This was the Vickers 'Gun-bus,' a 'pusher' + machine, with the propeller revolving behind the main planes between the + outriggers carrying the tail, with a seat right in front for a gunner who + was provided with a machine gun on a swivelling mount which had a free + field of fire in every direction forward. The device which proved the + death-blow for this type of aircraft during the war will be dealt with in + the appropriate place later, but the machine should not go unrecorded. + </p> + <p> + As a result of a number of accidents to monoplanes the Government + appointed a Committee at the end of 1912 to inquire into the causes of + these. The report which was presented in March, 1913, exonerated the + monoplane by coming to the conclusion that the accidents were not caused + by conditions peculiar to monoplanes, but pointed out certain desiderata + in aeroplane design generally which are worth recording. They recommended + that the wings of aeroplanes should be so internally braced as to have + sufficient strength in themselves not to collapse if the external bracing + wires should give way. The practice, more common in monoplanes than + biplanes, of carrying important bracing wires from the wings to the + undercarriage was condemned owing to the liability of damage from frequent + landings. They also pointed out the desirability of duplicating all main + wires and their attachments, and of using stranded cable for control + wires. Owing to the suspicion that one accident at least had been caused + through the tearing of the fabric away from the wing, it was recommended + that fabric should be more securely fastened to the ribs of the wings, and + that devices for preventing the spreading of tears should be considered. + In the last connection it is interesting to note that the French + Deperdussin firm produced a fabric wing-covering with extra strong threads + run at right-angles through the fabric at intervals in order to limit the + tearing to a defined area. + </p> + <p> + In spite, however, of the whitewashing of the monoplane by the Government + Committee just mentioned, considerable stir was occasioned later in the + year by the decision of the War office not to order any more monoplanes; + and from this time forward until the War period the British Army was + provided exclusively with biplanes. Even prior to this the popularity of + the monoplane had begun to wane. At the Olympia Aero Show in March, 1913, + biplanes for the first time outnumbered the 'single-deckers'(as the + Germans call monoplanes); which had the effect of reducing the + wing-loading. In the case of the biplanes exhibited this averaged about 4 + 1/2 lbs. per square foot, while in the case of the monoplanes in the same + exhibition the lowest was 5 1/2 lbs., and the highest over 8 1/2 lbs. per + square foot of area. It may here be mentioned that it was not until the + War period that the importance of loading per horse-power was recognised + as the true criterion of aeroplane efficiency, far greater interest being + displayed in the amount of weight borne per unit area of wing. + </p> + <p> + An idea of the state of development arrived at about this time may be + gained from the fact that the Commandant of the Military Wing of the Royal + Flying Corps in a lecture before the Royal Aeronautical Society read in + February, 1913, asked for single-seater scout aeroplanes with a speed of + 90 miles an hour and a landing speed of 45 miles an hour—a + performance which even two years later would have been considered modest + in the extreme. It serves to show that, although higher performances were + put up by individual machines on occasion, the general development had not + yet reached the stage when such performances could be obtained in machines + suitable for military purposes. So far as seaplanes were concerned, up to + the beginning of 1913 little attempt had been made to study the novel + problems involved, and the bulk of the machines at the Monaco Meeting in + April, 1913, for instance, consisted of land machines fitted with floats, + in many cases of a most primitive nature, without other alterations. Most + of those which succeeded in leaving the water did so through sheer pull of + engine power; while practically all were incapable of getting off except + in a fair sea, which enabled the pilot to jump the machine into the air + across the trough between two waves. Stability problems had not yet been + considered, and in only one or two cases was fin area added at the rear + high up, to counterbalance the effect of the floats low down in front. + Both twin and single-float machines were used, while the flying boat was + only just beginning to come into being from the workshops of Sopwith in + Great Britain, Borel-Denhaut in France, and Curtiss in America. In view of + the approaching importance of amphibious seaplanes, mention should be made + of the flying boat (or 'bat boat' as it was called, following Rudyard + Kipling) which was built by Sopwith in 1913 with a wheeled + landing-carriage which could be wound up above the bottom surface of the + boat so as to be out of the way when alighting on water. + </p> + <p> + During 1913 the (at one time almost universal) practice originated by the + Wright Brothers, of warping the wings for lateral stability, began to die + out and the bulk of aeroplanes began to be fitted with flaps (or + 'ailerons') instead. This was a distinct change for the better, as + continually warping the wings by bending down the extremities of the rear + spars was bound in time to produce 'fatigue' in that member and lead to + breakage; and the practice became completely obsolete during the next two + or three years. + </p> + <p> + The Gordon-Bennett race of September, 1913, was again won by a Deperdussin + machine, somewhat similar to that of the previous year, but with + exceedingly small wings, only 107 square feet in area. The shape of these + wings was instructive as showing how what, from the general utility point + of view, may be disadvantageous can, for a special purpose, be turned to + account. With a span of 21 feet, the chord was 5 feet, giving the + inefficient 'aspect ratio' of slightly over 4 to 1 only. The object of + this was to reduce the lift, and therefore the resistance, to as low a + point as possible. The total weight was 1,500 lbs., giving a wing-loading + of 14 lbs. per square foot—a hitherto undreamt-of figure. The result + was that the machine took an enormously long run before starting; and + after touching the ground on landing ran for nearly a mile before + stopping; but she beat all records by attaining a speed of 126 miles per + hour. Where this performance is mainly interesting is in contrast to the + machines of 1920, which with an even higher speed capacity would yet be + able to land at not more than 40 or 50 miles per hour, and would be + thoroughly efficient flying machines. + </p> + <p> + The Rheims Aviation Meeting, at which the Gordon-Bennett race was flown, + also saw the first appearance of the Morane 'Parasol' monoplane. The + Morane monoplane had been for some time an interesting machine as being + the only type which had no fixed surface in rear to give automatic + stability, the movable elevator being balanced through being hinged about + one-third of the way back from the front edge. This made the machine + difficult to fly except in the hands of experts, but it was very quick and + handy on the controls and therefore useful for racing purposes. In the + 'Parasol' the modification was introduced of raising the wing above the + body, the pilot looking out beneath it, in order to give as good a view as + possible. + </p> + <p> + Before passing to the year 1914 mention should be made of the feat + performed by Nesteroff, a Russian, and Pegoud, a French pilot, who were + the first to demonstrate the possibilities of flying upside-down and + looping the loop. Though perhaps not coming strictly within the purview of + a chapter on design (though certain alterations were made to the top + wing-bracing of the machine for this purpose) this performance was of + extreme importance to the development of aviation by showing the + possibility of recovering, given reasonable height, from any position in + the air; which led designers to consider the extra stresses to which an + aeroplane might be subjected and to take steps to provide for them by + increasing strength where necessary. + </p> + <p> + When the year 1914 opened a speed of 126 miles per hour had been attained + and a height of 19,600 feet had been reached. The Sopwith and Avro (the + forerunner of the famous training machine of the War period) were probably + the two leading tractor biplanes of the world, both two-seaters with a + speed variation from 40 miles per hour up to some 90 miles per hour with + 80 horse-power engines. The French were still pinning their faith mainly + to monoplanes, while the Germans were beginning to come into prominence + with both monoplanes and biplanes of the 'Taube' type. These had wings + swept backward and also upturned at the wing-tips which, though it gave a + certain measure of automatic stability, rendered the machine somewhat + clumsy in the air, and their performances were not on the whole as high as + those of either France or Great Britain. + </p> + <p> + Early in 1914 it became known that the experimental work of Edward Busk—who + was so lamentably killed during an experimental flight later in the year—following + upon the researches of Bairstow and others had resulted in the production + at the Royal Aircraft Factory at Farnborough of a truly automatically + stable aeroplane. This was the 'R.E.' (Reconnaissance Experimental), a + development of the B.E. which has already been referred to. The remarkable + feature of this design was that there was no particular device to which + one could point out as the cause of the stability. The stable result was + attained simply by detailed design of each part of the aeroplane, with due + regard to its relation to, and effect on, other parts in the air. Weights + and areas were so nicely arranged that under practically any conditions + the machine tended to right itself. It did not, therefore, claim to be a + machine which it was impossible to upset, but one which if left to itself + would tend to right itself from whatever direction a gust might come. When + the principles were extended to the 'B.E. 2c' type (largely used at the + outbreak of the War) the latter machine, if the engine were switched of f + at a height of not less than 1,000 feet above the ground, would after a + few moments assume its correct gliding angle and glide down to the ground. + </p> + <p> + The Paris Aero Salon of December, 1913, had been remarkable chiefly for + the large number of machines of which the chassis and bodywork had been + constructed of steel-tubing; for the excess of monoplanes over biplanes; + and (in the latter) predominance of 'pusher' machines (with propeller in + rear of the main planes) compared with the growing British preference for + 'tractors' (with air screw in front). Incidentally, the Maurice Farman, + the last relic of the old type box-kite with elevator in front appeared + shorn of this prefix, and became known as the 'short-horn' in + contradistinction to its front-elevatored predecessor which, owing to its + general reliability and easy flying capabilities, had long been + affectionately called the 'mechanical cow.' The 1913 Salon also saw some + lingering attempts at attaining automatic stability by pendulum and other + freak devices. + </p> + <p> + Apart from the appearance of 'R.E.1,' perhaps the most notable development + towards the end of 1913 was the appearance of the Sopwith 'Tabloid + 'tractor biplane. This single-seater machine, evolved from the two-seater + previously referred to, fitted with a Gnome engine of 80 horse-power, had + the, for those days, remarkable speed of 92 miles an hour; while a still + more notable feature was that it could remain in level flight at not more + than 37 miles per hour. This machine is of particular importance because + it was the prototype and forerunner of the successive designs of + single-seater scout fighting machines which were used so extensively from + 1914 to 1918. It was also probably the first machine to be capable of + reaching a height of 1,000 feet within one minute. It was closely followed + by the 'Bristol Bullet,' which was exhibited at the Olympia Aero Show of + March, 1914. This last pre-war show was mainly remarkable for the good + workmanship displayed—rather than for any distinct advance in + design. In fact, there was a notable diversity in the types displayed, but + in detailed design considerable improvements were to be seen, such as the + general adoption of stranded steel cable in place of piano wire for the + mail bracing. + </p> + <p> + <a name="link2H_4_0029" id="link2H_4_0029"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + IV. THE WAR PERIOD + </h2> + <p> + Up to this point an attempt has been made to give some idea of the + progress that was made during the eleven years that had elapsed since the + days of the Wrights' first flights. Much advance had been made and + aeroplanes had settled down, superficially at any rate, into more or less + standardised forms in three main types—tractor monoplanes, tractor + biplanes, and pusher biplanes. Through the application of the results of + experiments with models in wind tunnels to full-scale machines, + considerable improvements had been made in the design of wing sections, + which had greatly increased the efficiency of aeroplanes by raising the + amount of 'lift' obtained from the wing compared with the 'drag' (or + resistance to forward motion) which the same wing would cause. In the same + way the shape of bodies, interplane struts, etc., had been improved to be + of better stream-line shape, for the further reduction of resistance; + while the problems of stability were beginning to be tolerably well + understood. Records (for what they are worth) stood at 21,000 feet as far + as height was concerned, 126 miles per hour for speed, and 24 hours + duration. That there was considerable room for development is, however, + evidenced by a statement made by the late B. C. Hucks (the famous pilot) + in the course of an address delivered before the Royal Aeronautical + Society in July, 1914. 'I consider,' he said, 'that the present day + standard of flying is due far more to the improvement in piloting than to + the improvement in machines.... I consider those (early 1914) machines are + only slight improvements on the machines of three years ago, and yet they + are put through evolutions which, at that time, were not even dreamed of. + I can take a good example of the way improvement in piloting has + outdistanced improvement in machines—in the case of myself, my + 'looping' Bleriot. Most of you know that there is very little difference + between that machine and the 50 horse-power Bleriot of three years ago.' + This statement was, of course, to some extent an exaggeration and was by + no means agreed with by designers, but there was at the same time a germ + of truth in it. There is at any rate little doubt that the theory and + practice of aeroplane design made far greater strides towards becoming an + exact science during the four years of War than it had done during the six + or seven years preceding it. + </p> + <p> + It is impossible in the space at disposal to treat of this development + even with the meagre amount of detail that has been possible while + covering the 'settling down' period from 1911 to 1914, and it is proposed, + therefore, to indicate the improvements by sketching briefly the more + noticeable difference in various respects between the average machine of + 1914 and a similar machine of 1918. + </p> + <p> + In the first place, it was soon found that it was possible to obtain + greater efficiency and, in particular, higher speeds, from tractor + machines than from pusher machines with the air screw behind the main + planes. This was for a variety of reasons connected with the efficiency of + propellers and the possibility of reducing resistance to a greater extent + in tractor machines by using a 'stream-line' fuselage (or body) to connect + the main planes with the tail. Full advantage of this could not be taken, + however, owing to the difficulty of fixing a machine-gun in a forward + direction owing to the presence of the propeller. This was finally + overcome by an ingenious device (known as an 'Interrupter gear') which + allowed the gun to fire only when none of the propeller blades was passing + in front of the muzzle. The monoplane gradually fell into desuetude, + mainly owing to the difficulty of making that type adequately strong + without it becoming prohibitively heavy, and also because of its high + landing speed and general lack of manoeuvrability. The triplane was also + little used except in one or two instances, and, practically speaking, + every machine was of the biplane tractor type. + </p> + <p> + A careful consideration of the salient features leading to maximum + efficiency in aeroplanes—particularly in regard to speed and climb, + which were the two most important military requirements—showed that + a vital feature was the reduction in the amount of weight lifted per + horse-power employed; which in 1914 averaged from 20 to 25 lbs. This was + effected both by gradual increase in the power and size of the engines + used and by great improvement in their detailed design (by increasing + compression ratio and saving weight whenever possible); with the result + that the motive power of single-seater aeroplanes rose from 80 and 100 + horse-power in 1914 to an average of 200 to 300 horse-power, while the + actual weight of the engine fell from 3 1/2-4 lbs. per horse-power to an + average of 2 1/2 lbs. per horse-power. This meant that while a pre-war + engine of 100 horse-power would weigh some 400 lbs., the 1918 engine + developing three times the power would have less than double the weight. + The result of this improvement was that a scout aeroplane at the time of + the Armistice would have 1 horse-power for every 8 lbs. of weight lifted, + compared with the 20 or 25 lbs. of its 1914 predecessors. This produced a + considerable increase in the rate of climb, a good postwar machine being + able to reach 10,000 feet in about 5 minutes and 20,000 feet in under half + an hour. The loading per square foot was also considerably increased; this + being rendered possible both by improvement in the design of wing sections + and by more scientific construction giving increased strength. It will be + remembered that in the machine of the very early period each square foot + of surface had only to lift a weight of some 1 1/2 to 2 lbs., which by + 1914 had been increased to about 4 lbs. By 1918 aeroplanes habitually had + a loading of 8 lbs. or more per square foot of area; which resulted in + great increase in speed. Although a speed of 126 miles per hour had been + attained by a specially designed racing machine over a short distance in + 1914, the average at that period little exceeded, if at all, 100 miles per + hour; whereas in 1918 speeds of 130 miles per hour had become a + commonplace, and shortly afterwards a speed of over 166 miles an hour was + achieved. + </p> + <p> + In another direction, also, that of size, great developments were made. + Before the War a few machines fitted with more than one engine had been + built (the first being a triple Gnome-engined biplane built by Messrs + Short Bros. at Eastchurch in 1913), but none of large size had been + successfully produced, the total weight probably in no case exceeding + about 2 tons. In 1916, however, the twin engine Handley-Page biplane was + produced, to be followed by others both in this country and abroad, which + represented a very great increase in size and, consequently, load-carrying + capacity. By the end of the War period several types were in existence + weighing a total of 10 tons when fully loaded, of which some 4 tons or + more represented 'useful load' available for crew, fuel, and bombs or + passengers. This was attained through very careful attention to detailed + design, which showed that the material could be employed more efficiently + as size increased, and was also due to the fact that a large machine was + not liable to be put through the same evolutions as a small machine, and + therefore could safely be built with a lower factor of safety. Owing to + the fact that a wing section which is adopted for carrying heavy loads + usually has also a somewhat low lift to drag ratio, and is not therefore + productive of high speed, these machines are not as fast as light scouts; + but, nevertheless, they proved themselves capable of achieving speeds of + 100 miles an hour or more in some cases; which was faster than the average + small machine of 1914. + </p> + <p> + In one respect the development during the War may perhaps have proved to + be somewhat disappointing, as it might have been expected that great + improvements would be effected in metal construction, leading almost to + the abolition of wooden structures. Although, however, a good deal of + experimental work was done which resulted in overcoming at any rate the + worst of the difficulties, metal-built machines were little used (except + to a certain extent in Germany) chiefly on account of the need for rapid + production and the danger of delay resulting from switching over from + known and tried methods to experimental types of construction. The Germans + constructed some large machines, such as the giant Siemens-Schukhert + machine, entirely of metal except for the wing covering, while the Fokker + and Junker firms about the time of the Armistice in 1918 both produced + monoplanes with very deep all-metal wings (including the covering) which + were entirely unstayed externally, depending for their strength on + internal bracing. In Great Britain cable bracing gave place to a great + extent to 'stream-line wires,' which are steel rods rolled to a more or + less oval section, while tie-rods were also extensively used for the + internal bracing of the wings. Great developments in the economical use of + material were also made in the direction of using built-up main spars for + the wings and interplane struts; spars composed of a series of layers (or + 'laminations') of different pieces of wood also being used. + </p> + <p> + Apart from the metallic construction of aeroplanes an enormous amount of + work was done in the testing of different steels and light alloys for use + in engines, and by the end of the War period a number of aircraft engines + were in use of which the pistons and other parts were of such alloys; the + chief difficulty having been not so much in the design as in the + successful heat-treatment and casting of the metal. + </p> + <p> + An important development in connection with the inspection and testing of + aircraft parts, particularly in the case of metal, was the experimental + application of X-ray photography, which showed up latent defects, both in + the material and in manufacture, which would otherwise have passed + unnoticed. This method was also used to test the penetration of glue into + the wood on each side of joints, so giving a measure of the strength; and + for the effect of 'doping' the wings, dope being a film (of cellulose + acetate dissolved in acetone with other chemicals) applied to the covering + of wings and bodies to render the linen taut and weatherproof, besides + giving it a smooth surface for the lessening of 'skin friction' when + passing rapidly through the air. + </p> + <p> + An important result of this experimental work was that it in many cases + enabled designers to produce aeroplane parts from less costly material + than had previously been considered necessary, without impairing the + strength. It may be mentioned that it was found undesirable to use welded + joints on aircraft in any part where the material is subjectto a tensile + or bending load, owing to the danger resulting from bad workmanship + causing the material to become brittle—an effect which cannot be + discovered except by cutting through the weld, which, of course, involves + a test to destruction. Written, as it has been, in August, 1920, it is + impossible in this chapter to give any conception of how the developments + of War will be applied to commercial aeroplanes, as few truly commercial + machines have yet been designed, and even those still show distinct traces + of the survival of war mentality. When, however, the inevitable recasting + of ideas arrives, it will become evident, whatever the apparent + modification in the relative importance of different aspects of design, + that enormous advances were made under the impetus of War which have left + an indelible mark on progress. + </p> + <p> + We have, during the seventeen years since aeroplanes first took the air, + seen them grow from tentative experimental structures of unknown and + unknowable performance to highly scientific products, of which not only + the performances (in speed, load-carrying capacity, and climb) are known, + but of which the precise strength and degree of stability can be forecast + with some accuracy on the drawing board. For the rest, with the future + lies—apart from some revolutionary change in fundamental design—the + steady development of a now well-tried and well-found engineering + structure. + </p> + <p> + <a name="link2H_PART3" id="link2H_PART3"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + PART III. AEROSTATICS + </h2> + <p> + <a name="link2H_4_0031" id="link2H_4_0031"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + I. BEGINNINGS + </h2> + <p> + Francesco Lana, with his 'aerial ship,' stands as one of the first great + exponents of aerostatics; up to the time of the Montgolfier and Charles + balloon experiments, aerostatic and aerodynamic research are so + inextricably intermingled that it has been thought well to treat of them + as one, and thus the work of Lana, Veranzio and his parachute, Guzman's + frauds, and the like, have already been sketched. In connection with + Guzman, Hildebrandt states in his Airships Past and Present, a fairly + exhaustive treatise on the subject up to 1906, the year of its + publication, that there were two inventors—or charlatans—Lorenzo + de Guzman and a monk Bartolemeo Laurenzo, the former of whom constructed + an unsuccessful airship out of a wooden basket covered with paper, while + the latter made certain experiments with a machine of which no description + remains. A third de Guzman, some twenty-five years later, announced that + he had constructed a flying machine, with which he proposed to fly from a + tower to prove his success to the public. The lack of record of any fatal + accident overtaking him about that time seems to show that the experiment + was not carried out. + </p> + <p> + Galien, a French monk, published a book L'art de naviguer dans l'air in + 1757, in which it was conjectured that the air at high levels was lighter + than that immediately over the surface of the earth. Galien proposed to + bring down the upper layers of air and with them fill a vessel, which by + Archimidean principle would rise through the heavier atmosphere. If one + went high enough, said Galien, the air would be two thousand times as + light as water, and it would be possible to construct an airship, with + this light air as lifting factor, which should be as large as the town of + Avignon, and carry four million passengers with their baggage. How this + high air was to be obtained is matter for conjecture—Galien seems to + have thought in a vicious circle, in which the vessel that must rise to + obtain the light air must first be filled with it in order to rise. + </p> + <p> + Cavendish's discovery of hydrogen in 1776 set men thinking, and soon a + certain Doctor Black was suggesting that vessels might be filled with + hydrogen, in order that they might rise in the air. Black, however, did + not get beyond suggestion; it was Leo Cavallo who first made experiments + with hydrogen, beginning with filling soap bubbles, and passing on to + bladders and special paper bags. In these latter the gas escaped, and + Cavallo was about to try goldbeaters' skin at the time that the + Montgolfiers came into the field with their hot air balloon. + </p> + <p> + Joseph and Stephen Montgolfier, sons of a wealthy French paper + manufacturer, carried out many experiments in physics, and Joseph + interested himself in the study of aeronautics some time before the first + balloon was constructed by the brothers—he is said to have made a + parachute descent from the roof of his house as early as 1771, but of this + there is no proof. Galien's idea, together with study of the movement of + clouds, gave Joseph some hope of achieving aerostation through Galien's + schemes, and the first experiments were made by passing steam into a + receiver, which, of course, tended to rise—but the rapid + condensation of the steam prevented the receiver from more than + threatening ascent. The experiments were continued with smoke, which + produced only a slightly better effect, and, moreover, the paper bag into + which the smoke was induced permitted of escape through its pores; finding + this method a failure the brothers desisted until Priestley's work became + known to them, and they conceived the use of hydrogen as a lifting factor. + Trying this with paper bags, they found that the hydrogen escaped through + the pores of the paper. + </p> + <p> + Their first balloon, made of paper, reverted to the hot-air principle; + they lighted a fire of wool and wet straw under the balloon—and as a + matter of course the balloon took fire after very little experiment; + thereupon they constructed a second, having a capacity of 700 cubic feet, + and this rose to a height of over 1,000 feet. Such a success gave them + confidence, and they gave their first public exhibition on June 5th, 1783, + with a balloon constructed of paper and of a circumference of 112 feet. A + fire was lighted under this balloon, which, after rising to a height of + 1,000 feet, descended through the cooling of the air inside a matter of + ten minutes. At this the Academie des Sciences invited the brothers to + conduct experiments in Paris. + </p> + <p> + The Montgolfiers were undoubtedly first to send up balloons, but other + experimenters were not far behind them, and before they could get to Paris + in response to their invitation, Charles, a prominent physicist of those + days, had constructed a balloon of silk, which he proofed against escape + of gas with rubber—the Roberts had just succeeded in dissolving this + substance to permit of making a suitable coating for the silk. With a + quarter of a ton of sulphuric acid, and half a ton of iron filings and + turnings, sufficient hydrogen was generated in four days to fill Charles's + balloon, which went up on August 28th, 1783. Although the day was wet, + Paris turned out to the number of over 300,000 in the Champs de Mars, and + cannon were fired to announce the ascent of the balloon. This, rising very + rapidly, disappeared amid the rain clouds, but, probably bursting through + no outlet being provided to compensate for the escape of gas, fell soon in + the neighbourhood of Paris. Here peasants, ascribing evil supernatural + influence to the fall of such a thing from nowhere, went at it with the + implements of their craft—forks, hoes, and the like—and + maltreated it severely, finally attaching it to a horse's tail and + dragging it about until it was mere rag and scrap. + </p> + <p> + Meanwhile, Joseph Montgolfier, having come to Paris, set about the + construction of a balloon out of linen; this was in three diverse + sections, the top being a cone 30 feet in depth, the middle a cylinder 42 + feet in diameter by 26 feet in depth, and the bottom another cone 20 feet + in depth from junction with the cylindrical portion to its point. The + balloon was both lined and covered with paper, decorated in blue and gold. + Before ever an ascent could be attempted this ambitious balloon was caught + in a heavy rainstorm which reduced its paper covering to pulp and tore the + linen at its seams, so that a supervening strong wind tore the whole thing + to shreds. + </p> + <p> + Montgolfier's next balloon was spherical, having a capacity of 52,000 + cubic feet. It was made from waterproofed linen, and on September 19th, + 1783, it made an ascent for the palace courtyard at Versailles, taking up + as passengers a cock, a sheep, and a duck. A rent at the top of the + balloon caused it to descend within eight minutes, and the duck and sheep + were found none the worse for being the first living things to leave the + earth in a balloon, but the cock, evidently suffering, was thought to have + been affected by the rarefaction of the atmosphere at the tremendous + height reached—for at that time the general opinion was that the + atmosphere did not extend more than four or five miles above the earth's + surface. It transpired later that the sheep had trampled on the cock, + causing more solid injury than any that might be inflicted by rarefied air + in an eight-minute ascent and descent of a balloon. + </p> + <p> + For achieving this flight Joseph Montgolfier received from the King of + France a pension of of L40, while Stephen was given the order of St + Michael, and a patent of nobility was granted to their father. They were + made members of the Legion d'Honneur, and a scientific deputation, of + which Faujas de Saint-Fond, who had raised the funds with which Charles's + hydrogen balloon was constructed, presented to Stephen Montgolfier a gold + medal struck in honour of his aerial conquest. Since Joseph appears to + have had quite as much share in the success as Stephen, the presentation + of the medal to one brother only was in questionable taste, unless it was + intended to balance Joseph's pension. + </p> + <p> + Once aerostation had been proved possible, many people began the + construction of small balloons—the wholehole thing was regarded as a + matter of spectacles and a form of amusement by the great majority. A + certain Baron de Beaumanoir made the first balloon of goldbeaters' skin, + this being eighteen inches in diameter, and using hydrogen as a lifting + factor. Few people saw any possibilities in aerostation, in spite of the + adventures of the duck and sheep and cock; voyages to the moon were talked + and written, and there was more of levity than seriousness over ballooning + as a rule. The classic retort of Benjamin Franklin stands as an exception + to the general rule: asked what was the use of ballooning—'What's + the use of a baby?' he countered, and the spirit of that reply brought + both the dirigible and the aeroplane to being, later. + </p> + <p> + The next noteworthy balloon was one by Stephen Montgolfier, designed to + take up passengers, and therefore of rather large dimensions, as these + things went then. The capacity was 100,000 cubic feet, the depth being 85 + feet, and the exterior was very gaily decorated. A short, cylindrical + opening was made at the lower extremity, and under this a fire-pan was + suspended, above the passenger car of the balloon. On October 15th, 1783, + Pilatre de Rozier made the first balloon ascent—but the balloon was + held captive, and only allowed to rise to a height of 80 feet. But, a + little later in 1783, Rozier secured the honour of making the first ascent + in a free balloon, taking up with him the Marquis d'Arlandes. It had been + originally intended that two criminals, condemned to death, should risk + their lives in the perilous venture, with the prospect of a free pardon if + they made a safe descent, but d'Arlandes got the royal consent to + accompany Rozier, and the criminals lost their chance. Rozier and + d'Arlandes made a voyage lasting for twenty-five minutes, and, on landing, + the balloon collapsed with such rapidity as almost to suffocate Rozier, + who, however, was dragged out to safety by d'Arlandes. This first + aerostatic journey took place on November 21st, 1783. + </p> + <p> + Some seven months later, on June 4th, 1784, a Madame Thible ascended in a + free balloon, reaching a height of 9,000 feet, and making a journey which + lasted for forty-five minutes—the great King Gustavus of Sweden + witnessed this ascent. France grew used to balloon ascents in the course + of a few months, in spite of the brewing of such a storm as might have + been calculated to wipe out all but purely political interests. Meanwhile, + interest in the new discovery spread across the Channel, and on September + 15th, 1784, one Vincent Lunardi made the first balloon voyage in England, + starting from the Artillery Ground at Chelsea, with a cat and dog as + passengers, and landing in a field in the parish of Standon, near Ware. + There is a rather rare book which gives a very detailed account of this + first ascent in England, one copy of which is in the library of the Royal + Aeronautical Society; the venturesome Lunardi won a greater measure of + fame through his exploit than did Cody for his infinitely more courageous + and—from a scientific point of view—valuable first aeroplane + ascent in this country. + </p> + <p> + The Montgolfier type of balloon, depending on hot air for its lifting + power, was soon realised as having dangerous limitations. There was always + a possibility of the balloon catching fire while it was being filled, and + on landing there was further danger from the hot pan which kept up the + supply of hot air on the voyage—the collapsing balloon fell on the + pan, inevitably. The scientist Saussure, observing the filling of the + balloons very carefully, ascertained that it was rarefaction of the air + which was responsible for the lifting power, and not the heat in itself, + and, owing to the rarefaction of the air at normal temperature at great + heights above the earth, the limit of ascent for a balloon of the + Montgolfier type was estimated by him at under 9,000 feet. Moreover, since + the amount of fuel that could be carried for maintaining the heat of the + balloon after inflation was subject to definite limits, prescribed by the + carrying capacity of the balloon, the duration of the journey was + necessarily limited just as strictly. + </p> + <p> + These considerations tended to turn the minds of those interested in + aerostation to consideration of the hydrogen balloon evolved by Professor + Charles. Certain improvements had been made by Charles since his first + construction; he employed rubber-coated silk in the construction of a + balloon of 30 feet diameter, and provided a net for distributing the + pressure uniformly over the surface of the envelope; this net covered the + top half of the balloon, and from its lower edge dependent ropes hung to + join on a wooden ring, from which the car of the balloon was suspended—apart + from the extension of the net so as to cover in the whole of the envelope, + the spherical balloon of to-day is virtually identical with that of + Charles in its method of construction. He introduced the valve at the top + of the balloon, by which escape of gas could be controlled, operating his + valve by means of ropes which depended to the car of the balloon, and he + also inserted a tube, of about 7 inches diameter, at the bottom of the + balloon, not only for purposes of inflation, but also to provide a means + of escape for gas in case of expansion due to atmospheric conditions. + </p> + <p> + Sulphuric acid and iron filings were used by Charles for filling his + balloon, which required three days and three nights for the generation of + its 14,000 cubic feet of hydrogen gas. The inflation was completed on + December 1st, 1783, and the fittings carried included a barometer and a + grapnel form of anchor. In addition to this, Charles provided the first + 'ballon sonde' in the form of a small pilot balloon which he handed to + Montgolfier to launch before his own ascent, in order to determine the + direction and velocity of the wind. It was a graceful compliment to his + rival, and indicated that, although they were both working to the one end, + their rivalry was not a matter of bitterness. + </p> + <p> + Ascending on December 1st, 1783, Charles took with him one of the brothers + Robert, and with him made the record journey up to that date, covering a + period of three and three-quarter hours, in which time they journeyed some + forty miles. Robert then landed, and Charles ascended again alone, + reaching such a height as to feel the effects of the rarefaction of the + air, this very largely due to the rapidity of his ascent. Opening the + valve at the top of the balloon, he descended thirty-five minutes after + leaving Robert behind, and came to earth a few miles from the point of the + first descent. His discomfort over the rapid ascent was mainly due to the + fact that, when Robert landed, he forgot to compensate for the reduction + of weight by taking in further ballast, but the ascent proved the value of + the tube at the bottom of the balloon envelope, for the gas escaped very + rapidly in that second ascent, and, but for the tube, the balloon must + inevitably have burst in the air, with fatal results for Charles. + </p> + <p> + As in the case of aeroplane flight, as soon as the balloon was proved + practicable the flight across the English Channel was talked of, and + Rozier, who had the honour of the first flight, announced his intention of + being first to cross. But Blanchard, who had an idea for a 'flying car,' + anticipated him, and made a start from Dover on January 7th, 1785, taking + with him an American doctor named Jeffries. Blanchard fitted out his craft + for the journey very thoroughly, taking provisions, oars, and even wings, + for propulsion in case of need. He took so much, in fact, that as soon as + the balloon lifted clear of the ground the whole of the ballast had to be + jettisoned, lest the balloon should drop into the sea. Half-way across the + Channel the sinking of the balloon warned Blanchard that he had to part + with more than ballast to accomplish the journey, and all the equipment + went, together with certain books and papers that were on board the car. + The balloon looked perilously like collapsing, and both Blanchard and + Jeffries began to undress in order further to lighten their craft—Jeffries + even proposed a heroic dive to save the situation, but suddenly the + balloon rose sufficiently to clear the French coast, and the two voyagers + landed at a point near Calais in the Forest of Gaines, where a marble + column was subsequently erected to commemorate the great feat. + </p> + <p> + Rozier, although not first across, determined to be second, and for that + purpose he constructed a balloon which was to owe its buoyancy to a + combination of the hydrogen and hot air principles. There was a spherical + hydrogen balloon above, and beneath it a cylindrical container which could + be filled with hot air, thus compensating for the leakage of gas from the + hydrogen portion of the balloon—regulating the heat of his fire, he + thought, would give him perfect control in the matter of ascending and + descending. + </p> + <p> + On July 6th, 1785, a favourable breeze gave Rozier his opportunity of + starting from the French coast, and with a passenger aboard he cast off in + his balloon, which he had named the 'Aero-Montgolfiere.' There was a rapid + rise at first, and then for a time the balloon remained stationary over + the land, after which a cloud suddenly appeared round the balloon, + denoting that an explosion had taken place. Both Rozier and his companion + were killed in the fall, so that he, first to leave the earth by balloon, + was also first victim to the art of aerostation. + </p> + <p> + There followed, naturally, a lull in the enthusiasm with which ballooning + had been taken up, so far as France was concerned. In Italy, however, + Count Zambeccari took up hot-air ballooning, using a spirit lamp to give + him buoyancy, and on the first occasion when the balloon car was set on + fire Zambeccari let down his passenger by means of the anchor rope, and + managed to extinguish the fire while in the air. This reduced the buoyancy + of the balloon to such an extent that it fell into the Adriatic and was + totally wrecked, Zambeccari being rescued by fishermen. He continued to + experiment up to 1812, when he attempted to ascend at Bologna; the spirit + in his lamp was upset by the collision of the car with a tree, and the car + was again set on fire. Zambeccari jumped from the car when it was over + fifty feet above level ground, and was killed. With him the Rozier type of + balloon, combining the hydrogen and hot air principles, disappeared; the + combination was obviously too dangerous to be practical. + </p> + <p> + The brothers Robert were first to note how the heat of the sun acted on + the gases within a balloon envelope, and it has since been ascertained + that sun rays will heat the gas in a balloon to as much as 80 degrees + Fahrenheit greater temperature than the surrounding atmosphere; hydrogen, + being less affected by change of temperature than coal gas, is the most + suitable filling element, and coal gas comes next as the medium of + buoyancy. This for the free and non-navigable balloon, though for the + airship, carrying means of combustion, and in military work liable to + ignition by explosives, the gas helium seems likely to replace hydrogen, + being non-combustible. + </p> + <p> + In spite of the development of the dirigible airship, there remains work + for the free, spherical type of balloon in the scientific field. + Blanchard's companion on the first Channel crossing by balloon, Dr + Jeffries, was the first balloonist to ascend for purely scientific + purposes; as early as 1784 he made an ascent to a height of 9,000 feet, + and observed a fall in temperature of from degrees—at the level of + London, where he began his ascent—to 29 degrees at the maximum + height reached. He took up an electrometer, a hydrometer, a compass, a + thermometer, and a Toricelli barometer, together with bottles of water, in + order to collect samples of the air at different heights. In 1785 he made + a second ascent, when trigonometrical observations of the height of the + balloon were made from the French coast, giving an altitude of 4,800 feet. + </p> + <p> + The matter was taken up on its scientific side very early in America, + experiments in Philadelphia being almost simultaneous with those of the + Montgolfiers in France. The flight of Rozier and d'Arlandes inspired two + members of the Philadelphia Philosophical Academy to construct a balloon + or series of balloons of their own design; they made a machine which + consisted of no less than 47 small hydrogen balloons attached to a wicker + car, and made certain preliminary trials, using animals as passengers. + This was followed by a captive ascent with a man as passenger, and + eventually by the first free ascent in America, which was undertaken by + one James Wilcox, a carpenter, on December 28th, 1783. Wilcox, fearful of + falling into a river, attempted to regulate his landing by cutting slits + in some of the supporting balloons, which was the method adopted for + regulating ascent or descent in this machine. He first cut three, and + then, finding that the effect produced was not sufficient, cut three more, + and then another five—eleven out of the forty-seven. The result was + so swift a descent that he dislocated his wrist on landing. + </p> +<pre xml:space="preserve"> + A NOTE ON BALLONETS OR AIR BAGS. +</pre> + <p> + Meusnier, toward the end of the eighteenth century, was first to conceive + the idea of compensating for the loss of gas due to expansion by fitting + to the interior of a free balloon a ballonet, or air bag, which could be + pumped full of air so as to retain the shape and rigidity of the envelope. + </p> + <p> + The ballonet became particularly valuable as soon as airship construction + became general, and it was in the course of advance in Astra Torres design + that the project was introduced of using the ballonets in order to give + inclination from the horizontal. In the earlier Astra Torres, trimming was + accomplished by moving the car fore and aft—this in itself was an + advance on the separate 'sliding weigh' principle—and this was the + method followed in the Astra Torres bought by the British Government from + France in 1912 for training airship pilots. Subsequently, the two + ballonets fitted inside the envelope were made to serve for trimming by + the extent of their inflation, and this method of securing inclination + proved the best until exterior rudders, and greater engine power, + supplanted it, as in the Zeppelin and, in fact, all rigid types. + </p> + <p> + In the kite balloon, the ballonet serves the purpose of a rudder, filling + itself through the opening being kept pointed toward the wind—there + is an ingenious type of air scoop with non-return valve which assures + perfect inflation. In the S.S. type of airship, two ballonets are + provided, the supply of air being taken from the propeller draught by a + slanting aluminium tube to the underside of the envelope, where it meets a + longitudinal fabric hose which connects the two ballonet air inlets. In + this hose the non-return air valves, known as 'crab-pots,' are fitted, on + either side of the junction with the air-scoop. Two automatic air valves, + one for each ballonet, are fitted in the underside of the envelope, and, + as the air pressure tends to open these instead of keeping them shut, the + spring of the valve is set inside the envelope. Each spring is set to open + at a pressure of 25 to 28 mm. + </p> + <p> + <a name="link2H_4_0032" id="link2H_4_0032"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + II. THE FIRST DIRIGIBLES + </h2> + <p> + Having got off the earth, the very early balloonists set about the task of + finding a means of navigating the air but, lacking steam or other + accessory power to human muscle, they failed to solve the problem. Joseph + Montgolfier speedily exploded the idea of propelling a balloon either by + means of oars or sails, pointing out that even in a dead calm a speed of + five miles an hour would be the limit achieved. Still, sailing balloons + were constructed, even up to the time of Andree, the explorer, who + proposed to retard the speed of the balloon by ropes dragging on the + ground, and then to spread a sail which should catch the wind and permit + of deviation of the course. It has been proved that slight divergences + from the course of the wind can be obtained by this means, but no real + navigation of the air could be thus accomplished. + </p> + <p> + Professor Wellner, of Brunn, brought up the idea of a sailing balloon in + more practical fashion in 1883. He observed that surfaces inclined to the + horizontal have a slight lateral motion in rising and falling, and deduced + that by alternate lowering and raising of such surfaces he would be able + to navigate the air, regulating ascent and descent by increasing or + decreasing the temperature of his buoyant medium in the balloon. He + calculated that a balloon, 50 feet in diameter and 150 feet in length, + with a vertical surface in front and a horizontal surface behind, might be + navigated at a speed of ten miles per hour, and in actual tests at Brunn + he proved that a single rise and fall moved the balloon three miles + against the wind. His ideas were further developed by Lebaudy in the + construction of the early French dirigibles. + </p> + <p> + According to Hildebrandt,[*] the first sailing balloon was built in 1784 + by Guyot, who made his balloon egg-shaped, with the smaller end at the + back and the longer axis horizontal; oars were intended to propel the + craft, and naturally it was a failure. Carra proposed the use of paddle + wheels, a step in the right direction, by mounting them on the sides of + the car, but the improvement was only slight. Guyton de Morveau, entrusted + by the Academy of Dijon with the building of a sailing balloon, first used + a vertical rudder at the rear end of his construction—it survives in + the modern dirigible. His construction included sails and oars, but, + lacking steam or other than human propulsive power, the airship was a + failure equally with Guyot's. + </p> + <p> + [*] Airships Past and Present. + </p> + <p> + Two priests, Miollan and Janinet, proposed to drive balloons through the + air by the forcible expulsion of the hot air in the envelope from the rear + of the balloon. An opening was made about half-way up the envelope, + through which the hot air was to escape, buoyancy being maintained by a + pan of combustibles in the car. Unfortunately, this development of the + Montgolfier type never got a trial, for those who were to be spectators of + the first flight grew exasperated at successive delays, and in the end, + thinking that the balloon would never rise, they destroyed it. + </p> + <p> + Meusnier, a French general, first conceived the idea of compensating for + loss of gas by carrying an air bag inside the balloon, in order to + maintain the full expansion of the envelope. The brothers Robert + constructed the first balloon in which this was tried and placed the air + bag near the neck of the balloon which was intended to be driven by oars, + and steered by a rudder. A violent swirl of wind which was encountered on + the first ascent tore away the oars and rudder and broke the ropes which + held the air bag in position; the bag fell into the opening of the neck + and stopped it up, preventing the escape of gas under expansion. The Duc + de Chartres, who was aboard, realised the extreme danger of the envelope + bursting as the balloon ascended, and at 16,000 feet he thrust a staff + through the envelope—another account says that he slit it with his + sword—and thus prevented disaster. The descent after this rip in the + fabric was swift, but the passengers got off without injury in the + landing. + </p> + <p> + Meusnier, experimenting in various ways, experimented with regard to the + resistance offered by various shapes to the air, and found that an + elliptical shape was best; he proposed to make the car boat—shaped, + in order further to decrease the resistance, and he advocated an entirely + rigid connection between the car and the body of the balloon, as + indispensable to a dirigible.[*] He suggested using three propellers, + which were to be driven by hand by means of pulleys, and calculated that a + crew of eighty would be required to furnish sufficient motive power. + Horizontal fins were to be used to assure stability, and Meusnier + thoroughly investigated the pressures exerted by gases, in order to + ascertain the stresses to which the envelope would be subjected. More + important still, he went into detail with regard to the use of air bags, + in order to retain the shape of the balloon under varying pressures of gas + due to expansion and consequent losses; he proposed two separate + envelopes, the inner one containing gas, and the space between it and the + outer one being filled with air. Further, by compressing the air inside + the air bag, the rate of ascent or descent could be regulated. Lebaudy, + acting on this principle, found it possible to pump air at the rate of 35 + cubic feet per second, thus making good loss of ballast which had to be + thrown overboard. + </p> + <p> + [*] Hildebrandt. + </p> + <p> + Meusnier's balloon, of course, was never constructed, but his ideas have + been of value to aerostation up to the present time. His career ended in + the revolutionary army in 1793, when he was killed in the fighting before + Mayence, and the King of Prussia ordered all firing to cease until + Meusnier had been buried. No other genius came forward to carry on his + work, and it was realised that human muscle could not drive a balloon with + certainty through the air; experiment in this direction was abandoned for + nearly sixty years, until in 1852 Giffard brought the first practicable + power-driven dirigible to being. + </p> + <p> + Giffard, inventor of the steam injector, had already made balloon ascents + when he turned to aeronautical propulsion, and constructed a steam engine + of 5 horsepower with a weight of only 100 lbs.—a great achievement + for his day. Having got his engine, he set about making the balloon which + it was to drive; this he built with the aid of two other enthusiasts, + diverging from Meusnier's ideas by making the ends pointed, and keeping + the body narrowed from Meusnier's ellipse to a shape more resembling a + rather fat cigar. The length was 144 feet, and the greatest diameter only + 40 feet, while the capacity was 88,000 cubic feet. A net which covered the + envelope of the balloon supported a spar, 66 feet in length, at the end of + which a triangular sail was placed vertically to act as rudder. The car, + slung 20 feet below the spar, carried the engine and propeller. Engine and + boiler together weighed 350 lbs., and drove the 11 foot propeller at 110 + revolutions per minute. + </p> + <p> + As precaution against explosion, Giffard arranged wire gauze in front of + the stoke-hole of his boiler, and provided an exhaust pipe which + discharged the waste gases from the engine in a downward direction. With + this first dirigible he attained to a speed of between 6 and 8 feet per + second, thus proving that the propulsion of a balloon was a possibility, + now that steam had come to supplement human effort. + </p> + <p> + Three years later he built a second dirigible, reducing the diameter and + increasing the length of the gas envelope, with a view to reducing air + resistance. The length of this was 230 feet, the diameter only 33 feet, + and the capacity was 113,000 cubic feet, while the upper part of the + envelope, to which the covering net was attached, was specially covered to + ensure a stiffening effect. The car of this dirigible was dropped rather + lower than that of the first machine, in order to provide more thoroughly + against the danger of explosions. Giffard, with a companion named Yon as + passenger, took a trial trip on this vessel, and made a journey against + the wind, though slowly. In commencing to descend, the nose of the + envelope tilted upwards, and the weight of the car and its contents caused + the net to slip, so that just before the dirigible reached the ground, the + envelope burst. Both Giffard and his companion escaped with very slight + injuries. + </p> + <p> + Plans were immediately made for the construction of a third dirigible, + which was to be 1,970 feet in length, 98 feet in extreme diameter, and to + have a capacity of 7,800,000 cubic feet of gas. The engine of this giant + was to have weighed 30 tons, and with it Giffard expected to attain a + speed of 40 miles per hour. Cost prevented the scheme being carried out, + and Giffard went on designing small steam engines until his invention of + the steam injector gave him the funds to turn to dirigibles again. He + built a captive balloon for the great exhibition in London in 1868, at a + cost of nearly L30,000, and designed a dirigible balloon which was to have + held a million and three quarters cubic feet of gas, carry two boilers, + and cost about L40,000. The plans were thoroughly worked out, down to the + last detail, but the dirigible was never constructed. Giffard went blind, + and died in 1882—he stands as the great pioneer of dirigible + construction, more on the strength of the two vessels which he actually + built than on that of the ambitious later conceptions of his brain. + </p> + <p> + In 1872 Dupuy de Lome, commissioned by the French government, built a + dirigible which he proposed to drive by man-power—it was anticipated + that the vessel would be of use in the siege of Paris, but it was not + actually tested till after the conclusion of the war. The length of this + vessel was 118 feet, its greatest diameter 49 feet, the ends being + pointed, and the motive power was by a propeller which was revolved by the + efforts of eight men. The vessel attained to about the same speed as + Giffard's steam-driven airship; it was capable of carrying fourteen men, + who, apart from these engaged in driving the propeller, had to manipulate + the pumps which controlled the air bags inside the gas envelope. + </p> + <p> + In the same year Paul Haenlein, working in Vienna, produced an airship + which was a direct forerunner of the Lebaudy type, 164 feet in length, 30 + feet greatest diameter, and with a cubic capacity of 85,000 feet. + Semi-rigidity was attained by placing the car as close to the envelope as + possible, suspending it by crossed ropes, and the motive power was a gas + engine of the Lenoir type, having four horizontal cylinders, and giving + about 5 horse-power with a consumption of about 250 cubic feet of gas per + hour. This gas was sucked from the envelope of the balloon, which was kept + fully inflated by pumping in compensating air to the air bags inside the + main envelope. A propeller, 15 feet in diameter, was driven by the Lenoir + engine at 40 revolutions per minute. This was the first instance of the + use of an internal combustion engine in connection with aeronautical + experiments. + </p> + <p> + The envelope of this dirigible was rendered airtight by means of internal + rubber coating, with a thinner film on the outside. Coal gas, used for + inflation, formed a suitable fuel for the engine, but limited the height + to which the dirigible could ascend. Such trials as were made were carried + out with the dirigible held captive, and a speed of I 5 feet per second + was attained. Full experiment was prevented through funds running low, but + Haenlein's work constituted a distinct advance on all that had been done + previously. + </p> + <p> + Two brothers, Albert and Gaston Tissandier, were next to enter the field + of dirigible construction; they had experimented with balloons during the + Franc-Prussian War, and had attempted to get into Paris by balloon during + the siege, but it was not until 1882 that they produced their dirigible. + </p> + <p> + This was 92 feet in length and 32 feet in greatest diameter, with a cubic + capacity of 37,500 feet, and the fabric used was varnished cambric. The + car was made of bamboo rods, and in addition to its crew of three, it + carried a Siemens dynamo, with 24 bichromate cells, each of which weighed + 17 lbs. The motor gave out 1 1/2 horse-power, which was sufficient to + drive the vessel at a speed of up to 10 feet per second. This was not so + good as Haenlein's previous attempt and, after L2,000 had been spent, the + Tissandier abandoned their experiments, since a 5-mile breeze was + sufficient to nullify the power of the motor. + </p> + <p> + Renard, a French officer who had studied the problem of dirigible + construction since 1878, associated himself first with a brother officer + named La Haye, and subsequently with another officer, Krebs, in the + construction of the second dirigible to be electrically-propelled. La Haye + first approached Colonel Laussedat, in charge of the Engineers of the + French Army, with a view to obtaining funds, but was refused, in + consequence of the practical failure of all experiments since 1870. + Renard, with whom Krebs had now associated himself, thereupon went to + Gambetta, and succeeded in getting a promise of a grant of L8,000 for the + work; with this promise Renard and Krebs set to work. + </p> + <p> + They built their airship in torpedo shape, 165 feet in length, and of just + over 27 feet greatest diameter—the greatest diameter was at the + front, and the cubic capacity was 66,000 feet. The car itself was 108 feet + in length, and 4 1/2 feet broad, covered with silk over the bamboo + framework. The 23 foot diameter propeller was of wood, and was driven by + an electric motor connected to an accumulator, and yielding 8.5 + horsepower. The sweep of the propeller, which might have brought it in + contact with the ground in landing, was counteracted by rendering it + possible to raise the axis on which the blades were mounted, and a guide + rope was used to obviate damage altogether, in case of rapid descent. + There was also a 'sliding weight' which was movable to any required + position to shift the centre of gravity as desired. Altogether, with + passengers and ballast aboard, the craft weighed two tons. + </p> + <p> + In the afternoon of August 8th, 1884, Renard and Krebs ascended in the + dirigible—which they had named 'La France,' from the military + ballooning ground at Chalais-Meudon, making a circular flight of about + five miles, the latter part of which was in the face of a slight wind. + They found that the vessel answered well to her rudder, and the five-mile + flight was made successfully in a period of 23 minutes. Subsequent + experimental flights determined that the air speed of the dirigible was no + less than 14 1/2 miles per hour, by far the best that had so far been + accomplished in dirigible flight. Seven flights in all were made, and of + these five were completely successful, the dirigible returning to its + starting point with no difficulty. On the other two flights it had to be + towed back. + </p> + <p> + Renard attempted to repeat his construction on a larger scale, but funds + would not permit, and the type was abandoned; the motive power was not + sufficient to permit of more than short flights, and even to the present + time electric motors, with their necessary accumulators, are far too + cumbrous to compete with the self-contained internal combustion engine. + France had to wait for the Lebaudy brothers, just as Germany had to wait + for Zeppelin and Parseval. + </p> + <p> + Two German experimenters, Baumgarten and Wolfert, fitted a Daimler motor + to a dirigible balloon which made its first ascent at Leipzig in 1880. + This vessel had three cars, and placing a passenger in one of the outer + cars[*] distributed the load unevenly, so that the whole vessel tilted + over and crashed to the earth, the occupants luckily escaping without + injury. After Baumgarten's death, Wolfert determined to carry on with his + experiments, and, having achieved a certain measure of success, he + announced an ascent to take place on the Tempelhofer Field, near Berlin, + on June 12th, 1897. The vessel, travelling with the wind, reached a height + of 600 feet, when the exhaust of the motor communicated flame to the + envelope of the balloon, and Wolfert, together with a passenger he + carried, was either killed by the fall or burnt to death on the ground. + Giffard had taken special precautions to avoid an accident of this nature, + and Wolfert, failing to observe equal care, paid the full penalty. + </p> + <p> + [*] Hildebrandt. + </p> + <p> + Platz, a German soldier, attempting an ascent on the Tempelhofer Field in + the Schwartz airship in 1897, merely proved the dirigible a failure. The + vessel was of aluminium, 0.008 inch in thickness, strengthened by an + aluminium lattice work; the motor was two-cylindered petrol-driven; at the + first trial the metal developed such leaks that the vessel came to the + ground within four miles of its starting point. Platz, who was aboard + alone as crew, succeeded in escaping by jumping clear before the car + touched earth, but the shock of alighting broke up the balloon, and a + following high wind completed the work of full destruction. A second + account says that Platz, finding the propellers insufficient to drive the + vessel against the wind, opened the valve and descended too rapidly. + </p> + <p> + The envelope of this dirigible was 156 feet in length, and the method of + filling was that of pushing in bags, fill them with gas, and then pulling + them to pieces and tearing them out of the body of the balloon. A second + contemplated method of filling was by placing a linen envelope inside the + aluminium casing, blowing it out with air, and then admitting the gas + between the linen and the aluminium outer casing. This would compress the + air out of the linen envelope, which was to be withdrawn when the + aluminium casing had been completely filled with gas. + </p> + <p> + All this, however, assumes that the Schwartz type—the first rigid + dirigible, by the way—would prove successful. As it proved a failure + on the first trial, the problem of filling it did not arise again. + </p> + <p> + By this time Zeppelin, retired from the German army, had begun to devote + himself to the study of dirigible construction, and, a year after Schwartz + had made his experiment and had failed, he got together sufficient funds + for the formation of a limitedliability company, and started on the + construction of the first of his series of airships. The age of tentative + experiment was over, and, forerunner of the success of the + heavier-than-air type of flying machine, successful dirigible flight was + accomplished by Zeppelin in Germany, and by Santos-Dumont in France. + </p> + <p> + <a name="link2H_4_0033" id="link2H_4_0033"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + III. SANTOS-DUMONT + </h2> + <p> + A Brazilian by birth, Santos-Dumont began in Paris in the year 1898 to + make history, which he subsequently wrote. His book, My Airships, is a + record of his eight years of work on lighter-than-air machines, a period + in which he constructed no less than fourteen dirigible balloons, + beginning with a cubic capacity of 6,350 feet, and an engine of 3 + horse-power, and rising to a cubic capacity of 71,000 feet on the tenth + dirigible he constructed, and an engine of 60 horse-power, which was + fitted to the seventh machine in order of construction, the one which he + built after winning the Deutsch Prize. + </p> + <p> + The student of dirigible construction is recommended to Santos-Dumont's + own book not only as a full record of his work, but also as one of the + best stories of aerial navigation that has ever been written. Throughout + all his experiments, he adhered to the non-rigid type; his first dirigible + made its first flight on September 18th, 1898, starting from the Jardin + d'Acclimatation to the west of Paris; he calculated that his 3 horse-power + engine would yield sufficient power to enable him to steer clear of the + trees with which the starting-point was surrounded, but, yielding to the + advice of professional aeronauts who were present, with regard to the + placing of the dirigible for his start, he tore the envelope against the + trees. Two days later, having repaired the balloon, he made an ascent of + 1,300 feet. In descending, the hydrogen left in the balloon contracted, + and Santos-Dumont narrowly escaped a serious accident in coming to the + ground. + </p> + <p> + His second machine, built in the early spring of 1899, held over 7,000 + cubic feet of gas and gave a further 44 lbs. of ascensional force. The + balloon envelope was very long and very narrow; the first attempt at + flight was made in wind and rain, and the weather caused sufficient + contraction of the hydrogen for a wind gust to double the machine up and + toss it into the trees near its starting-point. The inventor immediately + set about the construction of 'Santos-Dumont No. 3,' on which he made a + number of successful flights, beginning on November 13th, 1899. On the + last of his flights, he lost the rudder of the machine and made a + fortunate landing at Ivry. He did not repair the balloon, considering it + too clumsy in form and its motor too small. Consequently No. 4 was + constructed, being finished on the 1st, August, 1900. It had a cubic + capacity of 14,800 feet, a length of 129 feet and greatest diameter of + 16.7 feet, the power plant being a 7 horse-power Buchet motor. + Santos-Dumont sat on a bicycle saddle fixed to the long bar suspended + under the machine, which also supported motor propeller, ballast; and + fuel. The experiment of placing the propeller at the stem instead of at + the stern was tried, and the motor gave it a speed of 100 revolutions per + minute. Professor Langley witnessed the trials of the machine, which + proved before the members of the International Congress of Aeronautics, on + September 19th, that it was capable of holding its own against a strong + wind. + </p> + <p> + Finding that the cords with which his dirigible balloon cars were + suspended offered almost as much resistance to the air as did the balloon + itself, Santos-Dumont substituted piano wire and found that the alteration + constituted greater progress than many a more showy device. He altered the + shape and size of his No. 4 to a certain extent and fitted a motor of 12 + horse-power. Gravity was controlled by shifting weights worked by a cord; + rudder and propeller were both placed at the stern. In Santos-Dumont's + book there is a certain amount of confusion between the No. 4 and No. 5 + airships, until he explains that 'No. 5' is the reconstructed 'No. 4.' It + was with No. 5 that he won the Encouragement Prize presented by the + Scientific Commission of the Paris Aero Club. This he devoted to the first + aeronaut who between May and October of 1900 should start from St Cloud, + round the Eiffel Tower, and return. If not won in that year, the prize was + to remain open the following year from May 1st to October 1st, and so on + annually until won. This was a simplification of the conditions of the + Deutsch Prize itself, the winning of which involved a journey of 11 + kilometres in 30 minutes. + </p> + <p> + The Santos-Dumont No. 5, which was in reality the modified No. 4 with new + keel, motor, and propeller, did the course of the Deutsch Prize, but with + it Santos-Dumont made no attempt to win the prize until July of 1901, when + he completed the course in 40 minutes, but tore his balloon in landing. On + the 8th August, with his balloon leaking, he made a second attempt, and + narrowly escaped disaster, the airship being entirely wrecked. Thereupon + he built No. 6 with a cubic capacity of 22,239 feet and a lifting power of + 1,518 lbs. + </p> + <p> + With this machine he won the Deutsch Prize on October 19th, 1901, starting + with the disadvantage of a side wind of 20 feet per second. He reached the + Eiffel Tower in 9 minutes and, through miscalculating his turn, only just + missed colliding with it. He got No. 6 under control again and succeeded + in getting back to his starting-point in 29 1/2 minutes, thus winning the + 125,000 francs which constituted the Deutsch Prize, together with a + similar sum granted to him by the Brazilian Government for the exploit. + The greater part of this money was given by Santos-Dumont to charities. + </p> + <p> + He went on building after this until he had made fourteen non-rigid + dirigibles; of these No. 12 was placed at the disposal of the military + authorities, while the rest, except for one that was sold to an American + and made only one trip, were matters of experiment for their maker. His + conclusions from his experiments may be gathered from his own work:— + </p> + <p> + 'On Friday, 31st July, 1903, Commandant Hirschauer and Lieutenant-Colonel + Bourdeaux spent the afternoon with me at my airship station at Neuilly St + James, where I had my three newest airships—the racing 'No. 7,' the + omnibus 'No. 10,' and the runabout 'No. 9'—ready for their study. + Briefly, I may say that the opinions expressed by the representatives of + the Minister of War were so unreservedly favourable that a practical test + of a novel character was decided to be made. Should the airship chosen + pass successfully through it the result will be conclusive of its military + value. + </p> + <p> + 'Now that these particular experiments are leaving my exclusively private + control I will say no more of them than what has been already published in + the French press. The test will probably consist of an attempt to enter + one of the French frontier towns, such as Belfort or Nancy, on the same + day that the airship leaves Paris. It will not, of course, be necessary to + make the whole journey in the airship. A military railway wagon may be + assigned to carry it, with its balloon uninflated, with tubes of hydrogen + to fill it, and with all the necessary machinery and instruments arranged + beside it. At some station a short distance from the town to be entered + the wagon may be uncoupled from the train, and a sufficient number of + soldiers accompanying the officers will unload the airship and its + appliances, transport the whole to the nearest open space, and at once + begin inflating the balloon. Within two hours from quitting the train the + airship may be ready for its flight to the interior of the + technically-besieged town. + </p> + <p> + 'Such may be the outline of the task—a task presented imperiously to + French balloonists by the events of 1870-1, and which all the devotion and + science of the Tissandier brothers failed to accomplish. To-day the + problem may be set with better hope of success. All the essential + difficulties may be revived by the marking out of a hostile zone around + the town that must be entered; from beyond the outer edge of this zone, + then, the airship will rise and take its flight—across it. + </p> + <p> + 'Will the airship be able to rise out of rifle range? I have always been + the first to insist that the normal place of the airship is in low + altitudes, and I shall have written this book to little purpose if I have + not shown the reader the real dangers attending any brusque vertical + mounting to considerable heights. For this we have the terrible Severo + accident before our eyes. In particular, I have expressed astonishment at + hearing of experimenters rising to these altitudes without adequate + purpose in their early stages of experience with dirigible balloons. All + this is very different, however, from a reasoned, cautious mounting, whose + necessity has been foreseen and prepared for.' + </p> + <p> + Probably owing to the fact that his engines were not of sufficient power, + Santos-Dumont cannot be said to have solved the problem of the military + airship, although the French Government bought one of his vessels. At the + same time, he accomplished much in furthering and inciting experiment with + dirigible airships, and he will always rank high among the pioneers of + aerostation. His experiments might have gone further had not the Wright + brothers' success in America and French interest in the problem of the + heavier-than-air machine turned him from the study of dirigibles to that + of the aeroplane, in which also he takes high rank among the pioneers, + leaving the construction of a successful military dirigible to such men as + the Lebaudy brothers, Major Parseval, and Zeppelin. + </p> + <p> + <a name="link2H_4_0034" id="link2H_4_0034"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + IV. THE MILITARY DIRIGIBLE + </h2> + <p> + Although French and German experiment in connection with the production of + an airship which should be suitable for military purposes proceeded side + by side, it is necessary to outline the development in the two countries + separately, owing to the differing character of the work carried out. So + far as France is concerned, experiment began with the Lebaudy brothers, + originally sugar refiners, who turned their energies to airship + construction in 1899. Three years of work went to the production of their + first vessel, which was launched in 1902, having been constructed by them + together with a balloon manufacturer named Surcouf and an engineer, + Julliot. The Lebaudy airships were what is known as semi-rigids, having a + spar which ran practically the full length of the gas bag to which it was + attached in such a way as to distribute the load evenly. The car was + suspended from the spar, at the rear end of which both horizontal and + vertical rudders were fixed, whilst stabilising fins were provided at the + stern of the gas envelope itself. The first of the Lebaudy vessels was + named the 'Jaune'; its length was 183 feet and its maximum diameter 30 + feet, while the cubic capacity was 80,000 feet. The power unit was a 40 + horse-power Daimler motor, driving two propellers and giving a maximum + speed of 26 miles per hour. This vessel made 29 trips, the last of which + took place in November, 1902, when the airship was wrecked through + collision with a tree. + </p> + <p> + The second airship of Lebaudy construction was 7 feet longer than the + first, and had a capacity of 94,000 cubic feet of gas with a triple air + bag of 17,500 cubic feet to compensate for loss of gas; this latter was + kept inflated by a rotary fan. The vessel was eventually taken over by the + French Government and may be counted the first dirigible airship + considered fit on its tests for military service. + </p> + <p> + Later vessels of the Lebaudy type were the 'Patrie' and 'Republique,' in + which both size and method of construction surpassed those of the two + first attempts. The 'Patrie' was fitted with a 60 horse-power engine which + gave a speed of 28 miles an hour, while the vessel had a radius of 280 + miles, carrying a crew of nine. In the winter of 1907 the 'Patrie' was + anchored at Verdun, and encountered a gale which broke her hold on her + mooring-ropes. She drifted derelict westward across France, the Channel, + and the British Isles, and was lost in the Atlantic. + </p> + <p> + The 'Republique' had an 80 horse-power motor, which, however, only gave + her the same speed as the 'Patrie.' She was launched in July, 1908, and + within three months came to an end which constituted a tragedy for France. + A propeller burst while the vessel was in the air, and one blade, flying + toward the envelope, tore in it a great gash; the airship crashed to + earth, and the two officers and two non-commissioned officers who were in + the car were instantaneously killed. + </p> + <p> + The Clement Bayard, and subsequently the Astra-Torres, non-rigids, + followed on the early Lebaudys and carried French dirigible construction + up to 1912. The Clement Bayard was a simple non-rigid having four lobes at + the stern end to assist stability. These were found to retard the speed of + the airship, which in the second and more successful construction was + driven by a Clement Bayard motor of 100 horse-power at a speed of 30 miles + an hour. On August 23rd, 1909, while being tried for acceptance by the + military authorities, this vessel achieved a record by flying at a height + of 5,000 feet for two hours. The Astra-Torres non-rigids were designed by + a Spaniard, Senor Torres, and built by the Astra Company. The envelope was + of trefoil shape, this being due to the interior rigging from the + suspension band; the exterior appearance is that of two lobes side by + side, overlaid by a third. The interior rigging, which was adopted with a + view to decreasing air resistance, supports a low-hung car from the centre + of the envelope; steering is accomplished by means of horizontal planes + fixed on the envelope at the stern, and vertical planes depending beneath + the envelope, also at the stern end. + </p> + <p> + One of the most successful of French pre-war dirigibles was a Clement + Bayard built in 1912. In this twin propellers were placed at the front and + horizontal and vertical rudders in a sort of box formation under the + envelope at the stern. The envelope was stream-lined, while the car of the + machine was placed well forward with horizontal controlling planes above + it and immediately behind the propellers. This airship, which was named + 'Dupuy de Lome,' may be ranked as about the most successful non-rigid + dirigible constructed prior to the War. + </p> + <p> + Experiments with non-rigids in Germany was mainly carried on by Major + Parseval, who produced his first vessel in 1906. The main feature of this + airship consisted in variation in length of the suspension cables at the + will of the operator, so that the envelope could be given an upward tilt + while the car remained horizontal in order to give the vessel greater + efficiency in climbing. In this machine, the propeller was placed above + and forward of the car, and the controlling planes were fixed directly to + the envelope near the forward end. A second vessel differed from the first + mainly in the matter of its larger size, variable suspension being again + employed, together with a similar method of control. The vessel was + moderately successful, and under Major Parseval's direction a third was + constructed for passenger carrying, with two engines of 120 horsepower, + each driving propellers of 13 feet diameter. This was the most successful + of the early German dirigibles; it made a number of voyages with a dozen + passengers in addition to its crew, as well as proving its value for + military purposes by use as a scout machine in manoeuvres. Later Parsevals + were constructed of stream-line form, about 300 feet in length, and with + engines sufficiently powerful to give them speeds up to 50 miles an hour. + </p> + <p> + Major Von Gross, commander of a Balloon Battalion, produced semi-rigid + dirigibles from 1907 onward. The second of these, driven by two 75 + horse-power Daimler motors, was capable of a speed of 27 miles an hour; in + September of 1908 she made a trip from and back to Berlin which lasted 13 + hours, in which period she covered 176 miles with four passengers and + reached a height of 4,000 feet. Her successor, launched in April of 1909, + carried a wireless installation, and the next to this, driven by four + motors of 75 horse-power each, reached a speed of 45 miles an hour. As + this vessel was constructed for military purposes, very few details either + of its speed or method of construction were made public. + </p> + <p> + Practically all these vessels were discounted by the work of Ferdinand von + Zeppelin, who set out from the first with the idea of constructing a rigid + dirigible. Beginning in 1898, he built a balloon on an aluminium framework + covered with linen and silk, and divided into interior compartments + holding linen bags which were capable of containing nearly 400,000 cubic + feet of hydrogen. The total length of this first Zeppelin airship was 420 + feet and the diameter 38 feet. Two cars were rigidly attached to the + envelope, each carrying a 16 horse-power motor, driving propellers which + were rigidly connected to the aluminium framework of the balloon. Vertical + and horizontal screws were used for lifting and forward driving and a + sliding weight was used to raise or lower the stem of the vessel out of + the horizontal in order to rise or descend without altering the load by + loss of ballast or the lift by loss of gas. + </p> + <p> + The first trial of this vessel was made in July of 1900, and was + singularly unfortunate. The winch by which the sliding weight was operated + broke, and the balloon was so bent that the working of the propellers was + interfered with, as was the steering. A speed of 13 feet per second was + attained, but on descending, the airship ran against some piles and was + further damaged. Repairs were completed by the end of September, 1900, and + on a second trial flight made on October 21st a speed of 30 feet per + second was reached. + </p> + <p> + Zeppelin was far from satisfied with the performance of this vessel, and + he therefore set about collecting funds for the construction of a second, + which was completed in 1905. By this time the internal combustion engine + had been greatly improved, and without any increase of weight, Zeppelin + was able to instal two motors of 85 horse-power each. The total capacity + was 367,000 cubic feet of hydrogen, carried in 16 gas bags inside the + framework, and the weight of the whole construction was 9 tons—a ton + less than that of the first Zeppelin airship. Three vertical planes at + front and rear controlled horizontal steering, while rise and fall was + controlled by horizontal planes arranged in box form. Accident attended + the first trial of this second airship, which took place over the Bodensee + on November 30th, 1905, 'It had been intended to tow the raft, to which it + was anchored, further from the shore against the wind. But the water was + too low to allow the use of the raft. The balloon was therefore mounted on + pontoons, pulled out into the lake, and taken in tow by a motor-boat. It + was caught by a strong wind which was blowing from the shore, and driven + ahead at such a rate that it overtook the motor-boat. The tow rope was + therefore at once cut, but it unexpectedly formed into knots and became + entangled with the airship, pulling the front end down into the water. The + balloon was then caught by the wind and lifted into the air, when the + propellers were set in motion. The front end was at this instant pointing + in a downward direction, and consequently it shot into the water, where it + was found necessary to open the valves.'[*] + </p> + <p> + [*] Hildebrandt, Airships Past and Present. + </p> + <p> + The damage done was repaired within six weeks, and the second trial was + made on January 17th, 1906. The lifting force was too great for the + weight, and the dirigible jumped immediately to 1,500 feet. The propellers + were started, and the dirigible brought to a lower level, when it was + found possible to drive against the wind. The steering arrangements were + found too sensitive, and the motors were stopped, when the vessel was + carried by the wind until it was over land—it had been intended that + the trial should be completed over water. A descent was successfully + accomplished and the dirigible was anchored for the night, but a gale + caused it so much damage that it had to be broken up. It had achieved a + speed of 30 feet per second with the motors developing only 36 horse-power + and, gathering from this what speed might have been accomplished with the + full 170 horse-power, Zeppelin set about the construction of No. 3, with + which a number of successful voyages were made, proving the value of the + type for military purposes. + </p> + <p> + No. 4 was the most notable of the early Zeppelins, as much on account of + its disastrous end as by reason of any superior merit in comparison with + No. 3. The main innovation consisted in attaching a triangular keel to the + under side of the envelope, with two gaps beneath which the cars were + suspended. Two Daimler Mercedes motors of 110 horse-power each were placed + one in each car, and the vessel carried sufficient fuel for a 60-hour + cruise with the motors running at full speed. Each motor drove a pair of + three-bladed metal propellers rigidly attached to the framework of the + envelope and about 15 feet in diameter. There was a vertical rudder at the + stern of the envelope and horizontal controlling planes were fixed on the + sides of the envelope. The best performances and the end of this dirigible + were summarised as follows by Major Squier:— + </p> + <p> + 'Its best performances were two long trips performed during the summer of + 1908. The first, on July 4th, lasted exactly 12 hours, during which time + it covered a distance of 235 miles, crossing the mountains to Lucerne and + Zurich, and returning to the balloon-house near Friedrichshafen, on Lake + Constance. The average speed on this trip was 32 miles per hour. On August + 4th, this airship attempted a 24-hour flight, which was one of the + requirements made for its acceptance by the Government. It left + Friedrichshafen in the morning with the intention of following the Rhine + as far as Mainz, and then returning to its starting-point, straight across + the country. A stop of 3 hours 30 minutes was made in the afternoon of the + first day on the Rhine, to repair the engine. On the return, a second stop + was found necessary near Stuttgart, due to difficulties with the motors, + and some loss of gas. While anchored to the ground, a storm arose which + broke loose the anchorage, and, as the balloon rose in the air, it + exploded and took fire (due to causes which have never been actually + determined and published) and fell to the ground, where it was completely + destroyed. On this journey, which lasted in all 31 hours 15 minutes, the + airship was in the air 20 hours 45 minutes, and covered a total distance + of 378 miles. + </p> + <p> + 'The patriotism of the German nation was aroused. Subscriptions were + immediately started, and in a short space of time a quarter of a million + pounds had been raised. A Zeppelin Society was formed to direct the + expenditure of this fund. Seventeen thousand pounds has been expended in + purchasing land near Friedrichshafen; workshops were erected, and it was + announced that within one year the construction of eight airships of the + Zeppelin type would be completed. Since the disaster to 'Zeppelin IV.' the + Crown Prince of Germany made a trip in 'Zeppelin No. 3,' which had been + called back into service, and within a very few days the German Emperor + visited Friedrichshafen for the purpose of seeing the airship in flight. + He decorated Count Zeppelin with the order of the Black Eagle. German + patriotism and enthusiasm has gone further, and the "German Association + for an Aerial Fleet" has been organised in sections throughout the + country. It announces its intention of building 50 garages (hangars) for + housing airships.' + </p> + <p> + By January of 1909, with well over a quarter of a million in hand for the + construction of Zeppelin airships, No. 3 was again brought out, probably + in order to maintain public enthusiasm in respect of the possible new + engine of war. In March of that year No. 3 made a voyage which lasted for + 4 hours over and in the vicinity of Lake Constance; it carried 26 + passengers for a distance of nearly 150 miles. + </p> + <p> + Before the end of March, Count Zeppelin determined to voyage from + Friedrichshafen to Munich, together with the crew of the airship and four + military officers. Starting at four in the morning and ascertaining their + route from the lights of railway stations and the ringing of bells in the + towns passed over, the journey was completed by nine o'clock, but a strong + south-west gale prevented the intended landing. The airship was driven + before the wind until three o'clock in the afternoon, when it landed + safely near Dingolfing; by the next morning the wind had fallen + considerably and the airship returned to Munich and landed on the parade + ground as originally intended. At about 3.30 in the afternoon, the + homeward journey was begun, Friedrichshafen being reached at about 7.30. + </p> + <p> + These trials demonstrated that sufficient progress had been made to + justify the construction of Zeppelin airships for use with the German + army. No. 3 had been manoeuvred safely if not successfully in half a gale + of wind, and henceforth it was known as 'SMS. Zeppelin I.,' at the bidding + of the German Emperor, while the construction of 'SMS. Zeppelin II.' was + rapidly proceeded with. The fifth construction of Count Zeppelin's was 446 + feet in length, 42 1/2 feet in diameter, and contained 530,000 cubic feet + of hydrogen gas in 17 separate compartments. Trial flights were made on + the 26th May, 1909, and a week later she made a record voyage of 940 + miles, the route being from Lake Constance over Ulm, Nuremberg, Leipzig, + Bitterfeld, Weimar, Heilbronn, and Stuttgart, descending near Goppingen; + the time occupied in the flight was upwards of 38 hours. + </p> + <p> + In landing, the airship collided with a pear-tree, which damaged the bows + and tore open two sections of the envelope, but repairs on the spot + enabled the return journey to Friedrichshafen to be begun 24 hours later. + In spite of the mishap the Zeppelin had once more proved itself as a + possible engine of war, and thenceforth Germany pinned its faith to the + dirigible, only developing the aeroplane to such an extent as to keep + abreast of other nations. By the outbreak of war, nearly 30 Zeppelins had + been constructed; considerably more than half of these were destroyed in + various ways, but the experiments carried on with each example of the type + permitted of improvements being made. The first fatality occurred in + September, 1913, when the fourteenth Zeppelin to be constructed, known as + Naval Zeppelin L.1, was wrecked in the North Sea by a sudden storm and her + crew of thirteen were drowned. About three weeks after this, Naval + Zeppelin L.2, the eighteenth in order of building, exploded in mid-air + while manoeuvring over Johannisthal. She was carrying a crew of 25, who + were all killed. + </p> + <p> + By 1912 the success of the Zeppelin type brought imitators. Chief among + them was the Schutte-Lanz, a Mannheim firm, which produced a rigid + dirigible with a wooden framework, wire braced. This was not a cylinder + like the Zeppelin, but reverted to the cigar shape and contained about the + same amount of gas as the Zeppelin type. The Schutte-Lanz was made with + two gondolas rigidly attached to the envelope in which the gas bags were + placed. The method of construction involved greater weight than was the + case with the Zeppelin, but the second of these vessels, built with three + gondolas containing engines, and a navigating cabin built into the hull of + the airship itself, proved quite successful as a naval scout until wrecked + on the islands off the coast of Denmark late in 1914. The last + Schutte-Lanz to be constructed was used by the Germans for raiding + England, and was eventually brought down in flames at Cowley. + </p> + <p> + <a name="link2H_4_0035" id="link2H_4_0035"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + V. BRITISH AIRSHIP DESIGN + </h2> + <p> + As was the case with the aeroplane, Great Britain left France and Germany + to make the running in the early days of airship construction; the balloon + section of the Royal Engineers was compelled to confine its energies to + work with balloons pure and simple until well after the twentieth century + had dawned, and such experiments as were made in England were done by + private initiative. As far back as 1900 Doctor Barton built an airship at + the Alexandra Palace and voyaged across London in it. Four years later Mr + E. T. Willows of Cardiff produced the first successful British dirigible, + a semi-rigid 74 feet in length and 18 feet in diameter, engined with a 7 + horse-power Peugot twin-cylindered motor. This drove a two-bladed + propeller at the stern for propulsion, and also actuated a pair of + auxiliary propellers at the front which could be varied in their direction + so as to control the right and left movements of the airship. This device + was patented and the patent was taken over by the British Government, + which by 1908 found Mr Willow's work of sufficient interest to regard it + as furnishing data for experiment at the balloon factory at Farnborough. + In 1909, Willows steered one of his dirigibles to London from Cardiff in a + little less than ten hours, making an average speed of over 14 miles an + hour. The best speed accomplished was probably considerably greater than + this, for at intervals of a few miles, Willows descended near the earth to + ascertain his whereabouts with the help of a megaphone. It must be added + that he carried a compass in addition to his megaphone. He set out for + Paris in November of 1910, reached the French coast, and landed near + Douai. Some damage was sustained in this landing, but, after repair, the + trip to Paris was completed. + </p> + <p> + Meanwhile the Government balloon factory at Farnborough began airship + construction in 1907; Colonel Capper, R.E., and S. F. Cody were jointly + concerned in the production of a semi-rigid. Fifteen thicknesses of + goldbeaters' skin—about the most expensive covering obtainable—were + used for the envelope, which was 25 feet in diameter. A slight shower of + rain in which the airship was caught led to its wreckage, owing to the + absorbent quality of the goldbeaters' skin, whereupon Capper and Cody set + to work to reproduce the airship and its defects on a larger scale. The + first had been named 'Nulli Secundus' and the second was named 'Nulli + Secundus II.' Punch very appropriately suggested that the first vessel + ought to have been named 'Nulli Primus,' while a possible third should be + christened 'Nulli Tertius.' 'Nulli Secundus II.' was fitted with a 100 + horse-power engine and had an envelope of 42 feet in diameter, the + goldbeaters' skin being covered in fabric and the car being suspended by + four bands which encircled the balloon envelope. In October of 1907, + 'Nulli Secundus II.' made a trial flight from Farnborough to London and + was anchored at the Crystal Palace. The wind sprung up and took the vessel + away from its mooring ropes, wrecking it after the one flight. + </p> + <p> + Stagnation followed until early in 1909, when a small airship fitted with + two 12 horse-power motors and named the 'Baby' was turned out from the + balloon factory. This was almost egg-shaped, the blunt end being forward, + and three inflated fins being placed at the tail as control members. A + long car with rudder and elevator at its rear-end carried the engines and + crew; the 'Baby' made some fairly successful flights and gave a good deal + of useful data for the construction of later vessels. + </p> + <p> + Next to this was 'Army Airship 2A 'launched early in 1910 and larger, + longer, and narrower in design than the Baby. The engine was an 80 + horse-power Green motor which drove two pairs of propellers; small + inflated control members were fitted at the stern end of the envelope, + which was 154 feet in length. The suspended car was 84 feet long, carrying + both engines and crew, and the Willows idea of swivelling propellers for + governing the direction was used in this vessel. In June of that year a + new, small-type dirigible, the 'Beta,' was produced, driven by a 30 + horse-power Green engine with which she flew over 3,000 miles. She was the + most successful British dirigible constructed up to that time, and her + successor, the 'Gamma,' was built on similar lines. The 'Gamma' was a + larger vessel, however, produced in 1912, with flat, controlling fins and + rudder at the rear end of the envelope, and with the conventional long car + suspended at some distance beneath the gas bag. By this time, the mooring + mast, carrying a cap of which the concave side fitted over the convex nose + of the airship, had been originated. The cap was swivelled, and, when + attached to it, an airship was held nose on to the wind, thus reducing by + more than half the dangers attendant on mooring dirigibles in the open. + </p> + <p> + Private subscription under the auspices of the Morning Post got together + sufficient funds in 1910 for the purchase of a Lebaudy airship, which was + built in France, flown across the Channel, and presented to the Army + Airship Fleet. This dirigible was 337 feet long, and was driven by two 135 + horse-power Panhard motors, each of which actuated two propellers. The + journey from Moisson to Aldershot was completed at a speed of 36 miles an + hour, but the airship was damaged while being towed into its shed. On May + of the following year, the Lebaudy was brought out for a flight, but, in + landing, the guide rope fouled in trees and sheds and brought the airship + broadside on to the wind; she was driven into some trees and wrecked to + such an exteent that rebuilding was considered an impossibility. A Clement + Bayard, bought by the army airship section, became scrap after even less + flying than had been accomplished by the Lebaudy. + </p> + <p> + In April of 1910, the Admiralty determined on a naval air service, and set + about the production of rigid airships which should be able to compete + with Zeppelins as naval scouts. The construction was entrusted to Vickers, + Ltd., who set about the task at their Barrow works and built something + which, when tested after a year's work, was found incapable of lifting its + own weight. This defect was remedied by a series of alterations, and + meanwhile the unofficial title of 'Mayfly' was given to the vessel. + </p> + <p> + Taken over by the Admiralty before she had passed any flying tests, the + 'Mayfly' was brought out on September 24th, 1911, for a trial trip, being + towed out from her shed by a tug. When half out from the shed, the + envelope was caught by a light cross-wind, and, in spite of the pull from + the tug, the great fabric broke in half, nearly drowning the crew, who had + to dive in order to get clear of the wreckage. + </p> + <p> + There was considerable similarity in form, though not in performance, + between the Mayfly and the prewar Zeppelin. The former was 510 feet in + length, cylindrical in form, with a diameter of 48 feet, and divided into + 19 gas-bag compartments. The motive power consisted of two 200 horse-power + Wolseley engines. After its failure, the Naval Air Service bought an + Astra-Torres airship from France and a Parseval from Germany, both of + which proved very useful in the early days of the War, doing patrol work + over the Channel before the Blimps came into being. + </p> + <p> + Early in 1915 the 'Blimp' or 'S.S.' type of coastal airship was evolved in + response to the demand for a vessel which could be turned out quickly and + in quantities. There was urgent demand, voiced by Lord Fisher, for a type + of vessel capable of maintaining anti-submarine patrol off the British + coasts, and the first S.S. airships were made by combining a gasbag with + the most available type of aeroplane fuselage and engine, and fitting + steering gear. The 'Blimp' consisted of a B.E. fuselage with engine and + geared-down propeller, and seating for pilot and observer, attached to an + envelope about 150 feet in length. With a speed of between 35 and 40 miles + an hour, the 'Blimp' had a cruising capacity of about ten hours; it was + fitted with wireless set, camera, machine-gun, and bombs, and for + submarine spotting and patrol work generally it proved invaluable, though + owing to low engine power and comparatively small size, its uses were + restricted to reasonably fair weather. For work farther out at sea and in + all weathers, airships known as the coast patrol type, and more commonly + as 'coastals,' were built, and later the 'N.S.' or North Sea type, still + larger and more weather-worthy, followed. By the time the last year of the + War came, Britain led the world in the design of non-rigid and semi-rigid + dirigibles. The 'S.S.' or 'Blimp' had been improved to a speed of 50 miles + an hour, carrying a crew of three, and the endurance record for the type + was 18 1/2 hours, while one of them had reached a height of 10,000 feet. + The North Sea type of non-rigid was capable of travelling over 20 hours at + full speed, or forty hours at cruising speed, and the number of non-rigids + belonging to the British Navy exceeded that of any other country. + </p> + <p> + It was owing to the incapacity—apparent or real—of the British + military or naval designers to produce a satisfactory rigid airship that + the 'N.S.' airship was evolved. The first of this type was produced in + 1916, and on her trials she was voted an unqualified success, in + consequence of which the building of several more was pushed on. The + envelope, of 360,000 cubic feet capacity, was made on the Astra-Torres + principle of three lobes, giving a trefoil section. The ship carried four + fins, to three of which the elevator and rudder flaps were attached; + petrol tanks were placed inside the envelope, under which was rigged a + long covered-in car, built up of a light steel tubular framework 35 feet + in length. The forward portion was covered with duralumin sheeting, an + aluminium alloy which, unlike aluminium itself, is not affected by the + action of sea air and water, and the remainder with fabric laced to the + framework. Windows and port-holes were provided to give light to the crew, + and the controls and navigating instruments were placed forward, with the + sleeping accommodation aft. The engines were mounted in a power unit + structure, separate from the car and connected by wooden gang ways + supported by wire cables. A complete electrical installation of two + dynamos and batteries for lights, signalling lamps, wireless, telephones, + etc., was carried, and the motive power consisted of either two 250 + horse-power Rolls-Royce engines or two 240 horse-power Fiat engines. The + principal dimensions of this type are length 262 feet, horizontal diameter + 56 feet 9 inches, vertical diameter 69 feet 3 inches. The gross lift is + 24,300 lbs. and the disposable lift without crew, petrol, oil, and ballast + 8,500 lbs. The normal crew carried for patrol work was ten officers and + men. This type holds the record of 101 hours continuous flight on patrol + duty. + </p> + <p> + In the matter of rigid design it was not until 1913 that the British + Admiralty got over the fact that the 'Mayfly' would not, and decided on a + further attempt at the construction of a rigid dirigible. The contract for + this was signed in March of 1914; work was suspended in the following + February and begun again in July, 1915, but it was not until January of + 1917 that the ship was finished, while her trials were not completed until + March of 1917, when she was taken over by the Admiralty. The details of + the construction and trial of this vessel, known as 'No. 9,' go to show + that she did not quite fill the contract requirements in respect of + disposable lift until a number of alterations had been made. The contract + specified that a speed of at least 45 miles per hour was to be attained at + full engine power, while a minimum disposable lift of 5 tons was to be + available for movable weights, and the airship was to be capable of rising + to a height of 2,000 feet. Driven by four Wolseley Maybach engines of 180 + horse-power each, the lift of the vessel was not sufficient, so it was + decided to remove the two engines in the after car and replace them by a + single engine of 250 horsepower. With this the vessel reached the contract + speed of 45 miles per hour with a cruising radius of 18 hours, equivalent + to 800 miles when the engines were running at full speed. The vessel + served admirably as a training airship, for, by the time she was + completed, the No. 23 class of rigid airship had come to being, and thus + No. 9 was already out of date. + </p> + <p> + Three of the 23 class were completed by the end of 1917; it was stipulated + that they should be built with a speed of at least 55 miles per hour, a + minimum disposable lift of 8 tons, and a capability of rising at an + average rate of not less than 1,000 feet per minute to a height of 3,000 + feet. The motive power consisted of four 250 horse-power Rolls-Royce + engines, one in each of the forward and after cars and two in a centre + car. Four-bladed propellers were used throughout the ship. + </p> + <p> + A 23X type followed on the 23 class, but by the time two ships had been + completed, this was practically obsolete. The No. 31 class followed the + 23X; it was built on Schutte-Lanz lines, 615 feet in length, 66 feet + diameter, and a million and a half cubic feet capacity. The hull was + similar to the later types of Zeppelin in shape, with a tapering stern and + a bluff, rounded bow. Five cars each carrying a 250 horse-power + Rolls-Royce engine, driving a single fixed propeller, were fitted, and on + her trials R.31 performed well, especially in the matter of speed. But the + experiment of constructing in wood in the Schutte-Lanz way adopted with + this vessel resulted in failure eventually, and the type was abandoned. + </p> + <p> + Meanwhile, Germany had been pushing forward Zeppelin design and straining + every nerve in the improvement of rigid dirigible construction, until L.33 + was evolved; she was generally known as a super-Zeppelin, and on September + 24th, 1916, six weeks after her launching, she was damaged by gun-fire in + a raid over London, being eventually compelled to come to earth at Little + Wigborough in Essex. The crew gave themselves up after having set fire to + the ship, and though the fabric was totally destroyed, the structure of + the hull remained intact, so that just as Germany was able to evolve the + Gotha bomber from the Handley-Page delivered at Lille, British naval + constructors were able to evolve the R.33 type of airship from the + Zeppelin framework delivered at Little Wigborough. Two vessels, R.33 and + R.34, were laid down for completion; three others were also put down for + construction, but, while R.33 and R.34 were built almost entirely from the + data gathered from the wrecked L.33, the three later vessels embody more + modern design, including a number of improvements, and more especially + greater disposable lift. It has been commented that while the British + authorities were building R.33 and R.34, Germany constructed 30 Zeppelins + on 4 slips, for which reason it may be reckoned a matter for + congratulation that the rigid airship did not decide the fate of the War. + The following particulars of construction of the R.33 and R.34 types are + as given by Major Whale in his survey of British Airships:— + </p> + <p> + 'In all its main features the hull structure of R.33 and R.34 follows the + design of the wrecked German Zeppelin airship L.33. 'The hull follows more + nearly a true stream-line shape than in the previous ships constructed of + duralumin, in which a greater proportion of the greater length was + parallel-sided. The Germans adopted this new shape from the Schutte-Lanz + design and have not departed from this practice. This consists of a short, + parallel body with a long, rounded bow and a long tapering stem + culminating in a point. The overall length of the ship is 643 feet with a + diameter of 79 feet and an extreme height of 92 feet. + </p> + <p> + 'The type of girders in this class has been much altered from those in + previous ships. The hull is fitted with an internal triangular keel + throughout practically the entire length. This forms the main corridor of + the ship, and is fitted with a footway down the centre for its entire + length. It contains water ballast and petrol tanks, bomb storage and crew + accommodation, and the various control wires, petrol pipes, and electric + leads are carried along the lower part. + </p> + <p> + 'Throughout this internal corridor runs a bridge girder, from which the + petrol and water ballast tanks are supported. These tanks are so arranged + that they can be dropped clear of the ship. Amidships is the cabin space + with sufficient room for a crew of twenty-five. Hammocks can be swung from + the bridge girder before mentioned. + </p> + <p> + 'In accordance with the latest Zeppelin practice, monoplane rudders and + elevators are fitted to the horizontal and vertical fins. + </p> + <p> + 'The ship is supported in the air by nineteen gas bags, which give a total + capacity of approximately two million cubic feet of gas. The gross lift + works out at approximately 59 1/2 tons, of which the total fixed weight is + 33 tons, giving a disposable lift of 26 1/2 tons. + </p> + <p> + 'The arrangement of cars is as follows: At the forward end the control car + is slung, which contains all navigating instruments and the various + controls. Adjoining this is the wireless cabin, which is also fitted for + wireless telephony. Immediately aft of this is the forward power car + containing one engine, which gives the appearance that the whole is one + large car. + </p> + <p> + 'Amidships are two wing cars, each containing a single engine. These are + small and just accommodate the engines with sufficient room for mechanics + to attend to them. Further aft is another larger car which contains an + auxiliary control position and two engines. + </p> + <p> + 'It will thus be seen that five engines are installed in the ship; these + are all of the same type and horsepower, namely, 250 horse-power Sunbeam. + R.33 was constructed by Messrs Armstrong, Whitworth, Ltd.; while her + sister ship R.34 was built by Messrs Beardmore on the Clyde.' + </p> + <p> + Of the two vessels, R.34 appeared rather more airworthy than her sister + ship; the lift of the ship justified the carrying of a greater quantity of + fuel than had been provided for, and, as she was considered suitable for + making a Transatlantic crossing, extra petrol tanks were fitted in the + hull and a new type of outer cover was fitted with a view to her making + the Atlantic crossing. She made a 21-hour cruise over the North of England + and the South of Scotland at the end of May, 1919, and subsequently went + for a longer cruise over Denmark, the Baltic, and the north coast of + Germany, remaining in the air for 56 hours in spite of very bad weather + conditions. Finally, July 2nd was selected as the starting date for the + cross Atlantic flight; the vessel was commanded by Major G. H. Scott, + A.F.C., with Captain G. S. Greenland as first officer, Second-Lieut. H. F. + Luck as second officer, and Lieut. J. D. Shotter as engineer officer. + There were also on board Brig.-Gen. E. P. Maitland, representing the Air + Ministry, Major J. E. M. Pritchard, representing the Admiralty, and + Lieut.-Col. W. H. Hemsley of the Army Aviation Department. In addition to + eight tons of petrol, R.34 carried a total number of 30 persons from East + Fortune to Long Island, N.Y. + </p> + <p> + There being no shed in America capable of accommodating the airship, she + had to be moored in the open for refilling with fuel and gas, and to make + the return journey almost immediately. + </p> + <p> + Brig.-Gen. Maitland's account of the flight, in itself a record as + interesting as valuable, divides the outward journey into two main stages, + the first from East Fortune to Trinity Bay, Newfoundland, a distance of + 2,050 sea miles, and the second and more difficult stage to Mineola Field, + Long Island, 1,080 sea miles. An easy journey was experienced until + Newfoundland was reached, but then storms and electrical disturbances + rendered it necessary to alter the course, in consequence of which petrol + began to run short. Head winds rendered the shortage still more acute, and + on Saturday, July 5th, a wireless signal was sent out asking for + destroyers to stand by to tow. However, after an anxious night, R.33 + landed safely at Mineola Field at 9.55 a.m. on July 6th, having + accomplished the journey in 108 hours 12 minutes. + </p> + <p> + She remained at Mineola until midnight of July 9th, when, although it had + been intended that a start should be made by daylight for the benefit of + New York spectators, an approaching storm caused preparations to be + advanced for immediate departure. She set out at 5.57 a.m. by British + summer time, and flew over New York in the full glare of hundreds of + searchlights before heading out over the Atlantic. A following wind + assisted the return voyage, and on July 13th, at 7.57 a.m., R.34 anchored + at Pulham, Norfolk, having made the return journey in 75 hours 3 minutes, + and proved the suitability of the dirigible for Transatlantic commercial + work. R.80, launched on July 19th, 1920, afforded further proof, if this + were needed. + </p> + <p> + It is to be noted that nearly all the disasters to airships have been + caused by launching and landing—the type is safe enough in the air, + under its own power, but its bulk renders it unwieldy for ground handling. + The German system of handling Zeppelins in and out of their sheds is, so + far, the best devised: this consists of heavy trucks running on rails + through the sheds and out at either end; on descending, the trucks are run + out, and the airship is securely attached to them outside the shed; the + trucks are then run back into the shed, taking the airship with them, and + preventing any possibility of the wind driving the envelope against the + side of the shed before it is safely housed; the reverse process is + adopted in launching, which is thus rendered as simple as it is safe. + </p> + <p> + <a name="link2H_4_0036" id="link2H_4_0036"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + VI. THE AIRSHIP COMMERCIALLY + </h2> + <p> + Prior to the war period, between the years 1910 and 1914, a German + undertaking called the Deutsche Luftfahrt Actien Gesellschaft conducted a + commercial Zeppelin service in which four airships known as the Sachsan, + Hansa, Victoria Louise, and Schwaben were used. During the four years of + its work, the company carried over 17,000 passengers, and over 100,000 + miles were flown without incurring one fatality and with only minor and + unavoidable accidents to the vessels composing the service. Although a + number of English notabilities made voyages in these airships, the success + of this only experiment in commercial aerostation seems to have been + forgotten since the war. There was beyond doubt a military aim in this + apparently peaceful use of Zeppelin airships; it is past question now that + all Germany's mechanical development in respect of land sea, and air + transport in the years immediately preceding the war, was accomplished + with the ulterior aim of military conquest, but, at the same time, the + running of this service afforded proof of the possibility of establishing + a dirigible service for peaceful ends, and afforded proof too, of the + value of the dirigible as a vessel of purely commercial utility. + </p> + <p> + In considering the possibility of a commercial dirigible service, it is + necessary always to bear in mind the disadvantages of first cost and + upkeep as compared with the aeroplane. The building of a modern rigid is + an exceedingly costly undertaking, and the provision of an efficient + supply of hydrogen gas to keep its compartments filled is a very large + item in upkeep of which the heavier-than-air machine goes free. Yet the + future of commercial aeronautics so far would seem to lie with the + dirigible where very long voyages are in question. No matter how the + aeroplane may be improved, the possibility of engine failure always + remains as a danger for work over water. In seaplane or flying boat form, + the danger is still present in a rough sea, though in the American + Transatlantic flight, N.C.3, taxi-ing 300 miles to the Azores after having + fallen to the water, proved that this danger is not so acute as is + generally assumed. Yet the multiple-engined rigid, as R.34 showed on her + return voyage, may have part of her power plant put out of action + altogether and still complete her voyage very successfully, which, in the + case of mail carrying and services run strictly to time, gives her an + enormous advantage over the heavier-than-air machine. + </p> + <p> + 'For commercial purposes,' General Sykes has remarked, 'the airship is + eminently adapted for long distance journeys involving non-stop flights. + It has this inherent advantage over the aeroplane, that while there + appears to be a limit to the range of the aeroplane as at present + constructed, there is practically no limit whatever to that of the + airship, as this can be overcome by merely increasing the size. It thus + appears that for such journeys as crossing the Atlantic, or crossing the + Pacific from the west coast of America to Australia or Japan, the airship + will be peculiarly suitable. It having been conceded that the scope of the + airship is long distance travel, the only type which need be considered + for this purpose is the rigid. The rigid airship is still in an embryonic + state, but sufficient has already been accomplished in this country, and + more particularly in Germany, to show that with increased capacity there + is no reason why, within a few years' time, airships should not be built + capable of completing the circuit of the globe and of conveying sufficient + passengers and merchandise to render such an undertaking a paying + proposition.' + </p> + <p> + The British R.38 class, embodying the latest improvements in airship + design outside Germany, gives a gross lift per airship of 85 tons and a + net lift of about 45 tons. The capacity of the gas bags is about two and + three-quarter million cubic feet, and, travelling at the rate of 45 miles + per hour, the cruising range of the vessel is estimated at 8.8 days. Six + engines, each of 350 horse-power, admit of an extreme speed of 70 miles + per hour if necessary. + </p> + <p> + The last word in German design is exemplified in the rigids L.70 and L.71, + together with the commercial airship 'Bodensee.' Previous to the + construction of these, the L.65 type is noteworthy as being the first + Zeppelin in which direct drive of the propeller was introduced, together + with an improved and lighter type of car. L.70 built in 1918 and destroyed + by the British naval forces, had a speed of about 75 miles per hour; L.71 + had a maximum speed of 72 miles per hour, a gas bag capacity of 2,420,000 + cubic feet, and a length of 743 feet, while the total lift was 73 tons. + Progress in design is best shown by the progress in useful load; in the + L.70 and L.71 class, this has been increased to 58.3 per cent, while in + the Bodensee it was ever higher. + </p> + <p> + As was shown in R.34's American flight, the main problem in connection + with the commercial use of dirigibles is that of mooring in the open. The + nearest to a solution of this problem, so far, consists in the mast + carrying a swivelling cap; this has been tried in the British service with + a non-rigid airship, which was attached to a mast in open country in a + gale of 52 miles an hour without the slightest damage to the airship. In + its commercial form, the mast would probably take the form of a tower, at + the top of which the cap would revolve so that the airship should always + face the wind, the tower being used for embarkation and disembarkation of + passengers and the provision of fuel and gas. Such a system would render + sheds unnecessary except in case of repairs, and would enormously decrease + the establishment charges of any commercial airship. + </p> + <p> + All this, however, is hypothetical. Remains the airship of to-day, + developed far beyond the promise of five years ago, capable, as has been + proved by its achievements both in Britain and in Germany, of undertaking + practically any given voyage with success. + </p> + <p> + <a name="link2H_4_0037" id="link2H_4_0037"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + VII. KITE BALLOONS + </h2> + <p> + As far back as the period of the Napoleonic wars, the balloon was given a + place in warfare, but up to the Franco-Prussian Prussian War of 1870-71 + its use was intermittent. The Federal forces made use of balloons to a + small extent in the American Civil War; they came to great prominence in + the siege of Paris, carrying out upwards of three million letters and + sundry carrier pigeons which took back messages into the besieged city. + Meanwhile, as captive balloons, the German and other armies used them for + observation and the direction of artillery fire. In this work the ordinary + spherical balloon was at a grave disadvantage; if a gust of wind struck + it, the balloon was blown downward and down wind, generally twirling in + the air and upsetting any calculations and estimates that might be made by + the observers, while in a wind of 25 miles an hour it could not rise at + all. The rotatory movement caused by wind was stopped by an experimenter + in the Russo-Japanese war, who fixed to the captive observation balloons a + fin which acted as a rudder. This did not stop the balloon from being + blown downward and away from its mooring station, but this tendency was + overcome by a modification designed in Germany by the Parseval-Siegsfield + Company, which originated what has since become familiar as the 'Sausage' + or kite balloon. This is so arranged that the forward end is tilted up + into the wind, and the underside of the gas bag, acting as a plane, gives + the balloon a lifting tendency in a wind, thus counteracting the tendency + of the wind to blow it downward and away from its mooring station. Smaller + bags are fitted at the lower and rear end of the balloon with openings + that face into the wind; these are thus kept inflated, and they serve the + purpose of a rudder, keeping the kite balloon steady in the air. + </p> + <p> + Various types of kite balloon have been introduced; the original German + Parseval-Siegsfield had a single air bag at the stern end, which was + modified to two, three, or more lobes in later varieties, while an + American experimental design attempted to do away with the attached lobes + altogether by stringing out a series of small air bags, kite fashion, in + rear of the main envelope. At the beginning of the War, Germany alone had + kite balloons, for the authorities of the Allied armies con-sidered that + the bulk of such a vessel rendered it too conspicuous a mark to permit of + its being serviceable. The Belgian arm alone possessed two which, on being + put into service, were found extremely useful. The French followed by + constructing kite balloons at Chalais Meudon, and then, after some months + of hostilities and with the example of the Royal Naval Air Service to + encourage them, the British military authorities finally took up the + construction and use of kite balloons for artillery-spotting and general + observation purposes. Although many were brought down by gun-fire, their + uses far outweighed their disadvantages, and toward the end of the War, + hardly a mile of front was without its 'Sausage.' + </p> + <p> + For naval work, kite balloons were carried in a specially constructed hold + in the forepart of certain vessels; when required for use, the covering of + the hold was removed, the kite balloon inflated and released to the + required height by means of winches as in the case of the land work. The + perfecting of the 'Coastal' and N.S. types of airship, together with the + extension of wireless telephony between airship and cruiser or other + warship, in all probability will render the use of the kite balloon + unnecessary in connection with naval scouting. But, during the War, + neither wireless telephony nor naval airships had developed sufficiently + to render the Navy independent of any means that might come to hand, and + the fitting of kite balloons in this fashion filled a need of the times. + </p> + <p> + A necessary accessory of the kite balloon is the parachute, which has a + long history. Da Vinci and Veranzio appear to have been the first + exponents, the first in the theory and the latter in the practice of + parachuting. Montgolfier experimented at Annonay before he constructed his + first hot air-balloon, and in 1783 a certain Lenormand dropped from a tree + in a parachute. Blanchard the balloonist made a spectacle of parachuting, + and made it a financial success; Cocking, in 1836, attempted to use an + inverted form of parachute; taken up to a height of 3,000 feet, he was cut + adrift, when the framework of the parachute collapsed and Cocking was + killed. + </p> + <p> + The rate of fall is slow in parachuting to the ground. Frau Poitevin, + making a descent from a height of 6,000 feet, took 45 minutes to reach the + ground, and, when she alighted, her husband, who had taken her up, had + nearly got his balloon packed up. Robertson, another parachutist is said + to have descended from a height of 10,000 feet in 35 minutes, or at a rate + of nearly 5 feet per second. During the War Brigadier-General Maitland + made a parachute descent from a height of 10,000 feet, the time taken + being about 20 minutes. + </p> + <p> + The parachute was developed considerably during the War period, the main + requirement, that of certainty in opening, being considerably developed. + Considered a necessary accessory for kite balloons, the parachute was also + partially adopted for use with aeroplanes in the later War period, when it + was contended that if a machine were shot down in flames, its occupants + would be given a far better chance of escape if they had parachutes. + Various trials were made to demonstrate the extreme efficiency of the + parachute in modern form, one of them being a descent from the upper ways + of the Tower Bridge to the waters of the Thames, in which short distance + the 'Guardian Angel' type of parachute opened and cushioned the descent + for its user. + </p> + <p> + For dirigibles, balloons, and kite balloons the parachute is an essential. + It would seem to be equally essential in the case of heavier-than-air + machines, but this point is still debated. Certainly it affords the + occupant of a falling aeroplane a chance, no matter how slender, of + reaching the ground in safety, and, for that reason, it would seem to have + a place in aviation as well as in aerostation. + </p> + <p> + <a name="link2H_PART4" id="link2H_PART4"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + PART IV. ENGINE DEVELOPMENT + </h2> + <p> + <a name="link2H_4_0039" id="link2H_4_0039"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + I. THE VERTICAL TYPE + </h2> + <p> + The balloon was but a year old when the brothers Robert, in 1784 attempted + propulsion of an aerial vehicle by hand-power, and succeeded, to a certain + extent, since they were able to make progress when there was only a slight + wind to counteract their work. But, as may be easily understood, the + manual power provided gave but a very slow speed, and in any wind it all + the would-be airship became an uncontrolled balloon. + </p> + <p> + Henson and Stringfellow, with their light steam engines, were first to + attempt conquest of the problem of mechanical propulsion in the air; their + work in this direction is so fully linked up with their constructed models + that it has been outlined in the section dealing with the development of + the aeroplane. But, very shortly after these two began, there came into + the field a Monsieur Henri Giffard, who first achieved success in the + propulsion by mechanical means of dirigible balloons, for his was the + first airship to fly against the wind. He employed a small steam-engine + developing about 3 horse-power and weighing 350 lbs. with boiler, fitting + the whole in a car suspended from the gas-bag of his dirigible. The + propeller which this engine worked was 11 feet in diameter, and the + inventor, who made several flights, obtained a speed of 6 miles an hour + against a slight wind. The power was not sufficient to render the + invention practicable, as the dirigible could only be used in calm + weather, but Giffard was sufficiently encouraged by his results to get out + plans for immense dirigibles, which through lack of funds he was unable to + construct. When, later, his invention of the steam-injector gave him the + means he desired, he became blind, and in 1882 died, having built but the + one famous dirigible. + </p> + <p> + This appears to have been the only instance of a steam engine being fitted + to a dirigible; the inherent disadvantage of this form of motive power is + that a boiler to generate the steam must be carried, and this, together + with the weight of water and fuel, renders the steam engine uneconomical + in relation to the lift either of plane or gas-bag. Again, even if the + weight could be brought down to a reasonable amount, the attention + required by steam plant renders it undesirable as a motive power for + aircraft when compared with the internal combustion engine. + </p> + <p> + Maxim, in Artificial and Natural Flight, details the engine which he + constructed for use with his giant experimental flying machine, and his + description is worthy of reproduction since it is that of the only steam + engine besides Giffard's, and apart from those used for the propulsion of + models, designed for driving an aeroplane. 'In 1889,' Maxim says, 'I had + my attention drawn to some very thin, strong, and comparatively cheap + tubes which were being made in France, and it was only after I had seen + these tubes that I seriously considered the question of making a flying + machine. I obtained a large quantity of them and found that they were very + light, that they would stand enormously high pressures, and generate a + very large quantity of steam. Upon going into a mathematical calculation + of the whole subject, I found that it would be possible to make a machine + on the aeroplane system, driven by a steam engine, which would be + sufficiently strong to lift itself into the air. I first made drawings of + a steam engine, and a pair of these engines was afterwards made. These + engines are constructed, for the most part, of a very high grade of cast + steel, the cylinders being only 3/32 of an inch thick, the crank shafts + hollow, and every part as strong and light as possible. They are compound, + each having a high-pressure piston with an area of 20 square inches, a + low-pressure piston of 50.26 square inches, and a common stroke of 1 foot. + When first finished they were found to weigh 300 lbs. each; but after + putting on the oil cups, felting, painting, and making some slight + alterations, the weight was brought up to 320 lbs. each, or a total of 640 + lbs. for the two engines, which have since developed 362 horsepower with a + steam pressure of 320 lbs. per square inch.' + </p> + <p> + The result is remarkable, being less than 2 lbs. weight per horse-power, + especially when one considers the state of development to which the steam + engine had attained at the time these experiments were made. The fining + down of the internal combustion engine, which has done so much to solve + the problems of power in relation to weight for use with aircraft, had not + then been begun, and Maxim had nothing to guide him, so far as work on the + part of his predecessors was concerned, save the experimental engines of + Stringfellow, which, being constructed on so small a scale in comparison + with his own, afforded little guidance. Concerning the factor of power, he + says: 'When first designing this engine, I did not know how much power I + might require from it. I thought that in some cases it might be necessary + to allow the high-pressure steam to enter the low-pressure cylinder + direct, but as this would involve a considerable loss, I constructed a + species of injector. This injector may be so adjusted that when the steam + in the boiler rises above a certain predetermined point, say 300 lbs., to + the square inch, it opens a valve and escapes past the high-pressure + cylinder instead of blowing off at the safety valve. In escaping through + this valve, a fall of about 200 lbs. pressure per square inch is made to + do work on the surrounding steam and drive it forward in the pipe, + producing a pressure on the low-pressure piston considerably higher than + the back-pressure on the high-pressure piston. In this way a portion of + the work which would otherwise be lost is utilised, and it is possible, + with an unlimited supply of steam, to cause the engines to develop an + enormous amount of power.' + </p> + <p> + With regard to boilers, Maxim writes, + </p> + <p> + 'The first boiler which I made was constructed something on the Herreshof + principle, but instead of having one simple pipe in one very long coil, I + used a series of very small and light pipes, connected in such a manner + that there was a rapid circulation through the whole—the tubes + increasing in size and number as the steam was generated. I intended that + there should be a pressure of about 100 lbs. more on the feed water end of + the series than on the steam end, and I believed that this difference in + pressure would be sufficient to ensure direct and positive circulation + through every tube in the series. The first boiler was exceedingly light, + but the workmanship, as far as putting the tubes together was concerned, + was very bad, and it was found impossible to so adjust the supply of water + as to make dry steam without overheating and destroying the tubes. + </p> + <p> + 'Before making another boiler I obtained a quantity of copper tubes, about + 8 feet long, 3/8 inch external diameter, and 1/50 of an inch thick. I + subjected about 100 of these tubes to an internal pressure of 1 ton per + square inch of cold kerosene oil, and as none of them leaked I did not + test any more, but commenced my experiments by placing some of them in a + white-hot petroleum fire. I found that I could evaporate as much as 26 1/2 + lbs. of water per square foot of heating surface per hour, and that with a + forced circulation, although the quantity of water passing was very small + but positive, there was no danger of overheating. I conducted many + experiments with a pressure of over 400 lbs. per square inch, but none of + the tubes failed. I then mounted a single tube in a white-hot furnace, + also with a water circulation, and found that it only burst under steam at + a pressure of 1,650 lbs. per square inch. A large boiler, having about 800 + square feet of heating surface, including the feed-water heater, was then + constructed. This boiler is about 4 1/2 feet wide at the bottom, 8 feet + long and 6 feet high. It weighs, with the casing, the dome, and the smoke + stack and connections, a little less than 1,000 lbs. The water first + passes through a system of small tubes—1/4 inch in diameter and 1/60 + inch thick—which were placed at the top of the boiler and + immediately over the large tubes.... This feed-water heater is found to be + very effective. It utilises the heat of the products of combustion after + they have passed through the boiler proper and greatly reduces their + temperature, while the feed-water enters the boiler at a temperature of + about 250 F. A forced circulation is maintained in the boiler, the + feed-water entering through a spring valve, the spring valve being + adjusted in such a manner that the pressure on the water is always 30 lbs. + per square inch in excess of the boiler pressure. This fall of 30 lbs. in + pressure acts upon the surrounding hot water which has already passed + through the tubes, and drives it down through a vertical outside tube, + thus ensuring a positive and rapid circulation through all the tubes. This + apparatus is found to act extremely well.' + </p> + <p> + Thus Maxim, who with this engine as power for his large aeroplane achieved + free flight once, as a matter of experiment, though for what distance or + time the machine was actually off the ground is matter for debate, since + it only got free by tearing up the rails which were to have held it down + in the experiment. Here, however, was a steam engine which was practicable + for use in the air, obviously, and only the rapid success of the internal + combustion engine prevented the steam-producing type from being developed + toward perfection. + </p> + <p> + The first designers of internal combustion engines, knowing nothing of the + petrol of these days, constructed their examples with a view to using gas + as fuel. As far back as 1872 Herr Paul Haenlein obtained a speed of about + 10 miles an hour with a balloon propelled by an internal combustion + engine, of which the fuel was gas obtained from the balloon itself. The + engine in this case was of the Lenoir type, developing some 6 horse-power, + and, obviously, Haenlein's flights were purely experimental and of short + duration, since he used the gas that sustained him and decreased the + lifting power of his balloon with every stroke of the piston of his + engine. No further progress appears to have been made with the + gas-consuming type of internal combustion engine for work with aircraft; + this type has the disadvantage of requiring either a gas-producer or a + large storage capacity for the gas, either of which makes the total weight + of the power plant much greater than that of a petrol engine. The latter + type also requires less attention when working, and the fuel is more + convenient both for carrying and in the matter of carburation. + </p> + <p> + The first airship propelled by the present-day type of internal combustion + engine was constructed by Baumgarten and Wolfert in 1879 at Leipzig, the + engine being made by Daimler with a view to working on benzine—petrol + as a fuel had not then come to its own. The construction of this engine is + interesting since it was one of the first of Daimler's make, and it was + the development brought about by the experimental series of which this + engine was one that led to the success of the motor-car in very few years, + incidentally leading to that fining down of the internal combustion engine + which has facilitated the development of the aeroplane with such + remarkable rapidity. Owing to the faulty construction of the airship no + useful information was obtained from Daimler's pioneer installation, as + the vessel got out of control immediately after it was first launched for + flight, and was wrecked. Subsequent attempts at mechanically-propelled + flight by Wolfert ended, in 1897, in the balloon being set on fire by an + explosion of benzine vapour, resulting in the death of both the aeronauts. + </p> + <p> + Daimler, from 1882 onward, devoted his attention to the perfecting of the + small, high-speed petrol engine for motor-car work, and owing to his + efforts, together with those of other pioneer engine-builders, the + motorcar was made a success. In a few years the weight of this type of + engine was reduced from near on a hundred pounds per horse-power to less + than a tenth of that weight, but considerable further improvement had to + be made before an engine suitable for use with aircraft was evolved. + </p> + <p> + The increase in power of the engines fitted to airships has made steady + progress from the outset; Haenlein's engine developed about 6 horse-power; + the Santos-Dumont airship of 1898 was propelled by a motor of 4 + horse-power; in 1902 the Lebaudy airship was fitted with an engine of 40 + horse-power, while, in 1910, the Lebaudy brothers fitted an engine of + nearly 300 horsepower to the airship they were then constructing—1,400 + horse-power was common in the airships of the War period, and the later + British rigids developed yet more. + </p> + <p> + Before passing on to consideration of the petrol-driven type of engine, it + is necessary to accord brief mention to the dirigible constructed in 1884 + by Gaston and Albert Tissandier, who at Grenelle, France, achieved a + directed flight in a wind of 8 miles an hour, obtaining their power for + the propeller from 1 1/3 horse-power Siemens electric motor, which weighed + 121 lbs. and took its current from a bichromate battery weighing 496 lbs. + A two-bladed propeller, 9 feet in diameter, was used, and the horse-power + output was estimated to have run up to 1 1/2 as the dirigible successfully + described a semicircle in a wind of 8 miles an hour, subsequently making + headway transversely to a wind of 7 miles an hour. The dirigible with + which this motor was used was of the conventional pointed-end type, with a + length of 92 feet, diameter of 30 feet, and capacity of 37,440 cubic feet + of gas. Commandant Renard, of the French army balloon corps, followed up + Tissandier's attempt in the next year—1885—making a trip from + Chalais-Meudon to Paris and returning to the point of departure quite + successfully. In this case the motive power was derived from an electric + plant of the type used by the Tissandiers, weighing altogether 1,174 lbs., + and developing 9 horsepower. A speed of 14 miles an hour was attained with + this dirigible, which had a length of 165 feet, diameter of 27 feet, and + capacity of 65,836 cubic feet of gas. + </p> + <p> + Reverting to the petrol-fed type again, it is to be noted that + Santos-Dumont was practically the first to develop the use of the ordinary + automobile engine for air work—his work is of such importance that + it has been considered best to treat of it as one whole, and details of + the power plants are included in the account of his experiments. Coming to + the Lebaudy brothers and their work, their engine of 1902 was a 40 + horse-power Daimler, four-cylindered; it was virtually a large edition of + the Daimler car engine, the arrangement of the various details being on + the lines usually adopted for the standard Daimler type of that period. + The cylinders were fully water-jacketed, and no special attempt toward + securing lightness for air work appears to have been made. + </p> + <p> + The fining down of detail that brought weight to such limits as would fit + the engine for work with heavier-than-air craft appears to have waited for + the brothers Wright. Toward the end of 1903 they fitted to their first + practicable flying machine the engine which made the historic first + aeroplane flight; this engine developed 30 horse-power, and weighed only + about 7 lbs. per horse-power developed, its design and workmanship being + far ahead of any previous design in this respect, with the exception of + the remarkable engine, designed by Manly, installed in Langley's ill-fated + aeroplane—or 'aerodrome,' as he preferred to call it—tried in + 1903. + </p> + <p> + The light weight of the Wright brothers' engine did not necessitate a high + number of revolutions per minute to get the requisite power; the speed was + only 1,300 revolutions per minute, which, with a piston stroke of 3.94 + inches, was quite moderate. Four cylinders were used, the cylinder + diameter being 4.42 inches; the engine was of the vertical type, arranged + to drive two propellers at a rate of about 350 revolutions per minute, + gearing being accomplished by means of chain drive from crank-shaft end to + propeller spindle. + </p> + <p> + The methods adopted by the Wrights for obtaining a light-weight engine + were of considerable interest, in view of the fact that the honour of + first achieving flight by means of the driven plane belongs to them—unless + Ader actually flew as he claimed. The cylinders of this first Wright + engine were separate castings of steel, and only the barrels were + jacketed, this being done by fixing loose, thin aluminium covers round the + outside of each cylinder. The combustion head and valve pockets were cast + together with the cylinder barrel, and were not water cooled. The inlet + valves were of the automatic type, arranged on the tops of the cylinders, + while the exhaust valves were also overhead, operated by rockers and + push-rods. The pistons and piston rings were of the ordinary type, made of + cast-iron, and the connecting rods were circular in form, with a hole + drilled down the middle of each to reduce the weight. + </p> + <p> + Necessity for increasing power and ever lighter weight in relation to the + power produced has led to the evolution of a number of different designs + of internal combustion engines. It was quickly realised that increasing + the number of cylinders on an engine was a better way of getting more + power than that of increasing the cylinder diameter, as the greater number + of cylinders gives better torque-even turning effect—as well as + keeping down the weight—this latter because the bigger cylinders + must be more stoutly constructed than the small sizes; this fact has led + to the construction of engines having as many as eighteen cylinders, + arranged in three parallel rows in order to keep the length of crankshaft + within reasonable limits. The aero engine of to-day may, roughly, be + divided into four classes: these are the V type, in which two rows of + cylinders are set parallel at a certain angle to each other; the radial + type, which consists of cylinders arranged radially and remaining + stationary while the crankshaft revolves; the rotary, where the cylinders + are disposed round a common centre and revolve round a stationary shaft, + and the vertical type, of four or six cylinders—seldom more than + this—arranged in one row. A modification of the V type is the + eighteen-cylindered engine—the Sunbeam is one of the best examples—in + which three rows of cylinders are set parallel to each other, working on a + common crankshaft. The development these four types started with that of + the vertical—the simplest of all; the V, radial, and rotary types + came after the vertical, in the order given. + </p> + <p> + The evolution of the motor-car led to the adoption of the vertical type of + internal combustion engine in preference to any other, and it followed + naturally that vertical engines should be first used for aeroplane + propulsion, as by taking an engine that had been developed to some extent, + and adapting it to its new work, the problem of mechanical flight was + rendered easier than if a totally new type had had to be evolved. It was + quickly realised—by the Wrights, in fact-that the minimum of weight + per horse-power was the prime requirement for the successful development + of heavier-than-air machines, and at the same time it was equally apparent + that the utmost reliability had to be obtained from the engine, while a + third requisite was economy, in order to reduce the weight of petrol + necessary for flight. + </p> + <p> + Daimler, working steadily toward the improvement of the internal + combustion engine, had made considerable progress by the end of last + century. His two-cylinder engine of 1897 was approaching to the + present-day type, except as regards the method of ignition; the cylinders + had 3.55 inch diameter, with a 4.75 inch piston stroke, and the engine was + rated at 4.5 brake horse-power, though it probably developed more than + this in actual running at its rated speed of 800 revolutions per minute. + Power was limited by the inlet and exhaust passages, which, compared with + present-day practice, were very small. The heavy castings of which the + engine was made up are accounted for by the necessity for considering + foundry practice of the time, for in 1897 castings were far below the + present-day standard. The crank-case of this two-cylinder vertical Daimler + engine was the only part made of aluminium, and even with this no attempt + was made to attain lightness, for a circular flange was cast at the bottom + to form a stand for the engine during machining and erection. The general + design can be followed from the sectional views, and these will show, too, + that ignition was by means of a hot tube on the cylinder head, which had + to be heated with a blow-lamp before starting the engine. With all its + well known and hated troubles, at that time tube ignition had an advantage + over the magneto, and the coil and accumulator system, in reliability; + sparking plugs, too, were not so reliable then as they are now. Daimler + fitted a very simple type of carburettor to this engine, consisting only + of a float with a single jet placed in the air passage. It may be said + that this twin-cylindered vertical was the first of the series from which + has been evolved the Mercedes-Daimler car and airship engines, built in + sizes up to and even beyond 240 horse-power. + </p> + <p> + In 1901 the development of the petrol engine was still so slight that it + did not admit of the construction, by any European maker, of an engine + weighing less than 12 lbs. per horse-power. Manly, working at the instance + of Professor Langley, produced a five-cylindered radial type engine, in + which both the design and workmanship showed a remarkable advance in + construction. At 950 revolutions per minute it developed 52.4 horse-power, + weighing only 2.4 pounds per horse-power; it was a very remarkable + achievement in engine design, considering the power developed in relation + to the total weight, and it was, too, an interruption in the development + of the vertical type which showed that there were other equally great + possibilities in design. + </p> + <p> + In England, the first vertical aero-engine of note was that designed by + Green, the cylinder dimensions being 4.15 inch diameter by 4.75 stroke—a + fairly complete idea of this engine can be obtained from the accompanying + diagrams. At a speed of 1,160 revolutions per minute it developed 35 brake + horse-power, and by accelerating up to 1,220 revolutions per minute a + maximum of 40 brake horse-power could be obtained—the + first-mentioned was the rated working speed of the engine for continuous + runs. A flywheel, weighing 23.5 lbs., was fitted to the engine, and this, + together with the ignition system, brought the weight up to 188 lbs., + giving 5.4 lbs. per horse-power. In comparison with the engine fitted to + the Wrights' aeroplane a greater power was obtained from approximately the + same cylinder volume, and an appreciable saving in weight had also been + effected. The illustration shows the arrangement of the vertical valves at + the top of the cylinder and the overhead cam shaft, while the position of + the carburettor and inlet pipes can be also seen. The water jackets were + formed by thin copper casings, each cylinder being separate and having its + independent jacket rigidly fastened to the cylinder at the top only, thus + allowing for free expansion of the casing; the joint at the bottom end was + formed by sliding the jacket over a rubber ring. Each cylinder was bolted + to the crank-case and set out of line with the crankshaft, so that the + crank has passed over the upper dead centre by the time that the piston is + at the top of its stroke when receiving the full force of fuel explosion. + The advantage of this desaxe setting is that the pressure in the cylinder + acts on the crank-pin with a more effective leverage during that part of + the stroke when that pressure is highest, and in addition the side + pressure of the piston on the cylinder wall, due to the thrust of the + connecting rod, is reduced. Possibly the charging of the cylinder is also + more complete by this arrangement, owing to the slower movement of the + piston at the bottom of its stroke allowing time for an increased charge + of mixture to enter the cylinder. + </p> + <p> + A 60 horse-power engine was also made, having four vertical cylinders, + each with a diameter of 5.5 inches and stroke of 5.75 inches, developing + its rated power at 1,100 revolutions per minute. By accelerating up to + 1,200 revolutions per minute 70 brake horsepower could be obtained, and a + maximum of 80 brake horse-power was actually attained with the type. The + flywheel, fitted as with the original 35 horse-power engine, weighed 37 + lbs.; with this and with the ignition system the total weight of the + engine was only 250 lbs., or 4.2 lbs. per horse-power at the normal + rating. In this design, however, low weight in relation to power was not + the ruling factor, for Green gave more attention to reliability and + economy of fuel consumption, which latter was approximately 0.6 pint of + petrol per brake horse-power per hour. Both the oil for lubricating the + bearings and the water for cooling the cylinders were circulated by pumps, + and all parts of the valve gear, etc., were completely enclosed for + protection from dust. + </p> + <p> + A later development of the Green engine was a six-cylindered vertical, + cylinder dimensions being 5.5 inch diameter by 6 inch stroke, developing + 120 brake horsepower when running at 1,250 revolutions per minute. The + total weight of the engine with ignition system 398 was 440 lbs., or 3.66 + lbs. per horse-power. One of these engines was used on the machine which, + in 1909, won the prize of L1,000 for the first circular mile flight, and + it may be noted, too, that S. F. Cody, making the circuit of England in + 1911, used a four-cylinder Green engine. Again, it was a Green engine that + in 1914 won the L5,000 prize offered for the best aero engine in the Naval + and Military aeroplane engine competition. + </p> + <p> + Manufacture of the Green engines, in the period of the War, had + standardised to the production of three types. Two of these were + six-cylinder models, giving respectively 100 and 150 brake horse-power, + and the third was a twelve-cylindered model rated at 275 brake + horse-power. + </p> + <p> + In 1910 J. S. Critchley compiled a list showing the types of engine then + being manufactured; twenty-two out of a total of seventy-six were of the + four-cylindered vertical type, and in addition to these there were two + six-cylindered verticals. The sizes of the four-cylinder types ranged from + 26 up to 118 brake horse-power; fourteen of them developed less than 50 + horse-power, and only two developed over 100 horse-power. + </p> + <p> + It became apparent, even in the early stages of heavier-than-air flying, + that four-cylinder engines did not produce the even torque that was + required for the rotation of the power shaft, even though a flywheel was + fitted to the engine. With this type of engine the breakage of air-screws + was of frequent occurrence, and an engine having a more regular rotation + was sought, both for this and to avoid the excessive vibration often + experienced with the four-cylinder type. Another, point that forced itself + on engine builders was that the increased power which was becoming + necessary for the propulsion of aircraft made an increase in the number of + cylinders essential, in order to obtain a light engine. An instance of the + weight reduction obtainable in using six cylinders instead of four is + shown in Critchley's list, for one of the four-cylinder engines developed + 118.5 brake horse-power and weighed 1,100 lbs., whereas a six-cylinder + engine by the same manufacturer developed 117.5 brake horse-power with a + weight of 880 lbs., the respective cylinder dimensions being 7.48 diameter + by 9.06 stroke for the four-cylinder engine, and 6.1 diameter by 7.28 + stroke for the six-cylinder type. + </p> + <p> + A list of aeroplane engines, prepared in 1912 by Graham Clark, showed + that, out of the total number of 112 engines then being manufactured, + forty-two were of the vertical type, and of this number twenty-four had + four-cylinders while sixteen were six-cylindered. The German aeroplane + engine trials were held a year later, and sixty-six engines entered the + competition, fourteen of these being made with air-cooled cylinders. All + of the ten engines that were chosen for the final trials were of the + water-cooled type, and the first place was won by a Benz four-cylinder + vertical engine which developed 102 brake horse-power at 1,288 revolutions + per minute. The cylinder dimensions of this engine were 5.1 inch diameter + by 7.1 inch stroke, and the weight of the engine worked out at 3.4 lbs. + per brake horse-power. During the trials the full-load petrol consumption + was 0.53 pint per horse-power per hour, and the amount of lubricating oil + used was 0.0385 pint per brake horse-power per hour. In general + construction this Benz engine was somewhat similar to the Green engine + already described; the overhead valves, fitted in the tops of the + cylinders, were similarly arranged, as was the cam-shaft; two springs were + fitted to each of the valves to guard against the possibility of the + engine being put out of action by breakage of one of the springs, and + ignition was obtained by two high-tension magnetos giving simultaneous + sparks in each cylinder by means of two sparking plugs—this dual + ignition reduced the possibility of ignition troubles. The cylinder + jackets were made of welded sheet steel so fitted around the cylinder that + the head was also water-cooled, and the jackets were corrugated in the + middle to admit of independent expansion. Even the lubrication system was + duplicated, two sets of pumps being used, one to circulate the main supply + of lubricating oil, and the other to give a continuous supply of fresh oil + to the bearings, so that if the supply from one pump failed the other + could still maintain effective lubrication. + </p> + <p> + Development of the early Daimler type brought about the four-cylinder + vertical Mercedes-Daimler engine of 85 horse-power, with cylinders of 5.5 + diameter with 5.9 inch stroke, the cylinders being cast in two pairs. The + overhead arrangement of valves was adopted, and in later designs push-rods + were eliminated, the overhead cam-shaft being adopted in their place. By + 1914 the four-cylinder Mercedes-Daimler had been partially displaced from + favour by a six-cylindered model, made in two sizes; the first of these + gave a nominal brake horse-power of 80, having cylinders of 4.1 inches + diameter by 5.5 inches stroke; the second type developed 100 horse-power + with cylinders 4.7 inches in diameter and 5.5 inches stroke, both types + being run at 1,200 revolutions per minute. The cylinders of both these + types were cast in pairs, and, instead of the water jackets forming part + of the casting, as in the design of the original four-cylinder + Mercedes-Daimler engine, they were made of steel welded to flanges on the + cylinders. Steel pistons, fitted with cast-iron rings, were used, and the + overhead arrangement of valves and cam-shaft was adopted. About 0.55 pint + per brake horse-power per hour was the usual fuel consumption necessary to + full load running, and the engine was also economical as regards the + consumption of lubricating oil, the lubricating system being 'forced' for + all parts, including the cam-shaft. The shape of these engines was very + well suited for work with aircraft, being narrow enough to admit of a + streamline form being obtained, while all the accessories could be so + mounted as to produce little or no wind resistance, and very little + obstruction to the pilot's view. + </p> + <p> + The eight-cylinder Mercedes-Daimler engine, used for airship propulsion + during the War, developed 240 brake horse-power at 1,100 revolutions per + minute; the cylinder dimensions were 6.88 diameter by 6.5 stroke—one + of the instances in which the short stroke in relation to bore was very + noticeable. + </p> + <p> + Other instances of successful vertical design-the types already detailed + are fully sufficient to give particulars of the type generally—are + the Panhard, Chenu, Maybach, N.A.G., Argus, Mulag, and the well-known + Austro-Daimler, which by 1917 was being copied in every combatant country. + There are also the later Wright engines, and in America the Wisconsin + six-cylinder vertical, weighing well under 4 lbs. per horse-power, is + evidence of the progress made with this first type of aero engine to + develop. + </p> + <p> + <a name="link2H_4_0040" id="link2H_4_0040"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + II. THE VEE TYPE + </h2> + <p> + An offshoot from the vertical type, doubling the power of this with only a + very slight—if any—increase in the length of crankshaft, the + Vee or diagonal type of aero engine leaped to success through the + insistent demand for greater power. Although the design came after that of + the vertical engine, by 1910, according to Critchley's list of aero + engines, there were more Vee type engines being made than any other type, + twenty-five sizes being given in the list, with an average rating of 57.4 + brake horse-power. + </p> + <p> + The arrangement of the cylinders in Vee form over the crankshaft, enabling + the pistons of each pair of opposite cylinders to act upon the same crank + pin, permits of a very short, compact engine being built, and also permits + of reduction of the weight per horsepower, comparing this with that of the + vertical type of engine, with one row of cylinders. Further, at the + introduction of this type of engine it was seen that crankshaft vibration, + an evil of the early vertical engines, was practically eliminated, as was + the want of longitudinal stiffness that characterised the higher-powered + vertical engines. + </p> + <p> + Of the Vee type engines shown in Critchley's list in 1910 nineteen + different sizes were constructed with eight cylinders, and with + horse-powers ranging from thirty to just over the hundred; the lightest of + these weighed 2.9 lbs. per horse-power—a considerable advance in + design on the average vertical engine, in this respect of weight per + horse-power. There were also two sixteen-cylinder engines of Vee design, + the larger of which developed 134 horse-power with a weight of only 2 lbs. + per brake horse-power. Subsequent developments have indicated that this + type, with the further development from it of the double-Vee, or engine + with three rows of cylinders, is likely to become the standard design of + aero engine where high powers are required. The construction permits of + placing every part so that it is easy of access, and the form of the + engine implies very little head resistance, while it can be placed on the + machine—supposing that machine to be of the single-engine type—in + such a way that the view of the pilot is very little obstructed while in + flight. + </p> + <p> + An even torque, or great uniformity of rotation, is transmitted to the + air-screw by these engines, while the design also permits of such good + balance of the engine itself that vibration is practically eliminated. The + angle between the two rows of cylinders is varied according to the number + of cylinders, in order to give working impulses at equal angles of + rotation and thus provide even torque; this angle is determined by + dividing the number of degrees in a circle by the number of cylinders in + either row of the engine. In an eight-cylindered Vee type engine, the + angle between the cylinders is 90 degrees; if it is a twelve-cylindered + engine, the angle drops to 60 degrees. + </p> + <p> + One of the earliest of the British-built Vee type engines was an + eight-cylinder 50 horse-power by the Wolseley Company, constructed in 1908 + with a cylinder bore of 3.75 inches and stroke of 5 inches, running at a + normal speed of 1,350 revolutions per minute. With this engine, a gearing + was introduced to enable the propeller to run at a lower speed than that + of the engine, the slight loss of efficiency caused by the friction of the + gearing being compensated by the slower speed of the air-screw, which had + higher efficiency than would have been the case if it had been run at the + engine speed. The ratio of the gearing—that is, the speed of the + air-screw relatively to that of the engine, could be chosen so as to suit + exactly the requirements of the air-screw, and the gearing itself, on this + engine, was accomplished on the half-speed shaft actuating the valves. + </p> + <p> + Very soon after this first design had been tried out, a second Vee type + engine was produced which, at 1,200 revolutions per minute, developed 60 + horse-power; the size of this engine was practically identical with that + of its forerunner, the only exception being an increase of half an inch in + the cylinder stroke—a very long stroke of piston in relation to the + bore of the cylinder. In the first of these two engines, which was + designed for airship propulsion, the weight had been about 8 lbs. per + brake horse-power, no special attempt appearing to have been made to fine + down for extreme lightness; in this 60 horse-power design, the weight was + reduced to 6.1 lbs. per horse-power, counting the latter as normally + rated; the engine actually gave a maximum of 75 brake horse-power, + reducing the ratio of weight to power very considerably below the figure + given. + </p> + <p> + The accompanying diagram illustrates a later Wolseley model, end + elevation, the eight-cylindered 120 horse-power Vee type aero engine of + the early war period. With this engine, each crank pin has two connecting + rods bearing on it, these being placed side by side and connected to the + pistons of opposite cylinders and the two cylinders of the pair are + staggered by an amount equal to the width of the connecting rod bearing, + to afford accommodation for the rods. The crankshaft was a nickel chrome + steel forging, machined hollow, with four crank pins set at 180 degrees to + each other, and carried in three bearings lined with anti-friction metal. + The connecting rods were made of tubular nickel chrome steel, and the + pistons of drawn steel, each being fitted with four piston rings. Of these + the two rings nearest to the piston head were of the ordinary cast-iron + type, while the others were of phosphor bronze, so arranged as to take the + side thrust of the piston. The cylinders were of steel, arranged in two + groups or rows of four, the angular distance between them being 90 + degrees. In the space above the crankshaft, between the cylinder rows, was + placed the valve-operating mechanism, together with the carburettor and + ignition system, thus rendering this a very compact and accessible engine. + The combustion heads of the cylinders were made of cast-iron, screwed into + the steel cylinder barrels; the water-jacket was of spun aluminium, with + one end fitting over the combustion head and the other free to slide on + the cylinder; the water-joint at the lower end was made tight by a + Dermatine ring carried between small flanges formed on the cylinder + barrel. Overhead valves were adopted, and in order to make these as large + as possible the combustion chamber was made slightly larger in diameter + than the cylinder, and the valves set at an angle. Dual ignition was + fitted in each cylinder, coil and accumulator being used for starting and + as a reserve in case of failure of the high-tension magneto system fitted + for normal running. There was a double set of lubricating pumps, ensuring + continuity of the oil supply to all the bearings of the engine. + </p> + <p> + The feature most noteworthy in connection with the running of this type of + engine was its flexibility; the normal output of power was obtained with + 1,150 revolutions per minute of the crankshaft, but, by accelerating up to + 1,400 revolutions, a maximum of 147 brake horse-power could be obtained. + The weight was about 5 lbs. per horse-power, the cylinder dimensions being + 5 inches bore by 7 inches stroke. Economy in running was obtained, the + fuel consumption being 0.58 pint per brake horse-power per hour at full + load, with an expenditure of about 0.075 pint of lubricating oil per brake + horse-power per hour. + </p> + <p> + Another Wolseley Vee type that was standardised was a 90 horse-power + eight-cylinder engine running at 1,800 revolutions per minute, with a + reducing gear introduced by fitting the air screw on the half-speed shaft. + First made semi-cooled—the exhaust valve was left air-cooled, and + then entirely water-jacketed—this engine demonstrated the advantage + of full water cooling, for under the latter condition the same power was + developed with cylinders a quarter of an inch less in diameter than in the + semi-cooled pattern; at the same time the weight was brought down to 4 1/2 + lbs. per horsepower. + </p> + <p> + A different but equally efficient type of Vee design was the Dorman + engine, of which an end elevation is shown; this developed 80 brake + horse-power at a speed of 1,300 revolutions per minute, with a cylinder + bore of 5 inches; each cylinder was made in cast-iron in one piece with + the combustion chamber, the barrel only being water-jacketed. Auxiliary + exhaust ports were adopted, the holes through the cylinder wall being + uncovered by the piston at the bottom of its stroke—the piston, 4.75 + inches in length, was longer than its stroke, so that these ports were + covered when it was at the top of the cylinder. The exhaust discharged + through the ports into a belt surrounding the cylinder, the belts on the + cylinders being connected so that the exhaust gases were taken through a + single pipe. The air was drawn through the crank case, before reaching the + carburettor, this having the effect of cooling the oil in the crank case + as well as warming the air and thus assisting in vaporising the petrol for + each charge of the cylinders. The inlet and exhaust valves were of the + overhead type, as may be gathered from the diagram, and in spite of + cast-iron cylinders being employed a light design was obtained, the total + weight with radiator, piping, and water being only 5.5 lbs. per + horse-power. + </p> + <p> + Here was the antithesis of the Wolseley type in the matter of bore in + relation to stroke; from about 1907 up to the beginning of the war, and + even later, there was controversy as to which type—that in which the + bore exceeded the stroke, or vice versa—gave greater efficiency. The + short-stroke enthusiasts pointed to the high piston speed of the + long-stroke type, while those who favoured the latter design contended + that full power could not be obtained from each explosion in the + short-stroke type of cylinder. It is now generally conceded that the + long-stroke engine yields higher efficiency, and in addition to this, so + far as car engines are concerned, the method of rating horse-power in + relation to bore without taking stroke into account has given the + long-stroke engine an advantage, actual horse-power with a long stroke + engine being in excess of the nominal rating. This may have had some + influence on aero engine design, but, however this may have been, the + long-stroke engine has gradually come to favour, and its rival has taken + second place. + </p> + <p> + For some time pride of place among British Vee type engines was held by + the Sunbeam Company, which, owing to the genius of Louis Coatalen, + together with the very high standard of construction maintained by the + firm, achieved records and fame in the middle and later periods of the + war. Their 225 horse-power twelve-cylinder engine ran at a normal speed of + 2,000 revolutions per minute; the air screw was driven through gearing at + half this speed, its shaft being separate from the timing gear and carried + in ball-bearings on the nose-piece of the engine. The cylinders were of + cast-iron, entirely water-cooled; a thin casing formed the water-jacket, + and a very light design was obtained, the weight being only 3.2 lbs. per + horse-power. The first engine of Sunbeam design had eight cylinders and + developed 150 horse-power at 2,000 revolutions per minute; the final type + of Vee design produced during the war was twelve-cylindered, and yielded + 310 horse-power with cylinders 4.3 inches bore by 6.4 inches stroke. + Evidence in favour of the long-stroke engine is afforded in this type as + regards economy of working; under full load, working at 2,000 revolutions + per minute, the consumption was 0.55 pints of fuel per brake horse-power + per hour, which seems to indicate that the long stroke permitted of full + use being made of the power resulting from each explosion, in spite of the + high rate of speed of the piston. + </p> + <p> + Developing from the Vee type, the eighteen-cylinder 475 brake horse-power + engine, designed during the war, represented for a time the limit of power + obtainable from a single plant. It was water-cooled throughout, and the + ignition to each cylinder was duplicated; this engine proved fully + efficient, and economical in fuel consumption. It was largely used for + seaplane work, where reliability was fully as necessary as high power. + </p> + <p> + The abnormal needs of the war period brought many British firms into the + ranks of Vee-type engine-builders, and, apart from those mentioned, the + most notable types produced are the Rolls-Royce and the Napier. The first + mentioned of these firms, previous to 1914 had concentrated entirely on + car engines, and their very high standard of production in this department + of internal combustion engine work led, once they took up the making of + aero engines, to extreme efficiency both of design and workmanship. The + first experimental aero engine, of what became known as the 'Eagle' type, + was of Vee design—it was completed in March of 1915—and was so + successful that it was standardised for quantity production. How far the + original was from the perfection subsequently ascertained is shown by the + steady increase in developed horse-power of the type; originally designed + to develop 200 horse-power, it was developed and improved before its first + practical trial in October of 1915, when it developed 255 horsepower on a + brake test. Research and experiment produced still further improvements, + for, without any enlargement of the dimensions, or radical alteration in + design, the power of the engine was brought up to 266 horse-power by March + of 1916, the rate of revolutions of 1,800 per minute being maintained + throughout. July, 1916 gave 284 horse-power; by the cud of the year this + had been increased to 322 horse-power; by September of 1917 the increase + was to 350 horse-power, and by February of 1918 then 'Eagle' type of + engine was rated at 360 horse-power, at which standard it stayed. But + there is no more remarkable development in engine design than this, a 75 + per cent increase of power in the same engine in a period of less than + three years. + </p> + <p> + To meet the demand for a smaller type of engine for use on training + machines, the Rolls-Royce firm produced the 'Hawk' Vee-type engine of 100 + horsepower, and, intermediately between this and the 'Eagle,' the 'Falcon' + engine came to being with an original rated horse-power of 205 at 1,800 + revolutions per minute, in April of 1916. Here was another case of growth + of power in the same engine through research, almost similar to that of + the 'Eagle' type, for by July of 1918 the 'Falcon' was developing 285 + horse-power with no radical alteration of design. Finally, in response to + the constant demand for increase of power in a single plant, the + Rolls-Royce company designed and produced the 'Condor' type of engine, + which yielded 600 horse-power on its first test in August of 1918. The + cessation of hostilities and consequent falling off in the demand for + extremely high-powered plants prevented the 'Condor' being developed to + its limit, as had been the 'Falcon' and 'Eagle' types. + </p> + <p> + The 'Eagle 'engine was fitted to the two Handley-Page aeroplanes—which + made flights from England to India—it was virtually standard on the + Handley-Page bombers of the later War period, though to a certain extent + the American 'Liberty' engine was also used. Its chief record, however, is + that of being the type fitted to the Vickers-Vimy aeroplane which made the + first Atlantic flight, covering the distance of 1,880 miles at a speed + averaging 117 miles an hour. + </p> + <p> + The Napier Company specialised on one type of engine from the outset, a + power plant which became known as the 'Lion' engine, giving 450 + horse-power with twelve cylinders arranged in three rows of four each. + Considering the engine as 'dry,' or without fuel and accessories, an + abnormally light weight per horse-power—only 1.89 lbs.—was + attained when running at the normal rate of revolution. The cylinders and + water-jackets are of steel, and there is fitted a detachable aluminium + cylinder head containing inlet and exhaust valves and valve actuating + mechanism; pistons are of aluminium alloy, and there are two inlet and two + exhaust valves to each cylinder, the whole of the valve mechanism being + enclosed in an oil-tight aluminium case. Connecting rods and crankshaft + are of steel, the latter being machined from a solid steel forging and + carried in five roller bearings and one plain bearing at the forward end. + The front end of the crank-case encloses reduction gear for the propeller + shaft, together with the shaft and bearings. There are two suction and one + pressure type oil pumps driven through gears at half-engine speed, and two + 12 spark magnetos, giving 2 sparks in each cylinder. + </p> + <p> + The cylinders are set with the central row vertical, and the two side rows + at angles of 60 degrees each; cylinder bore is 5 1/2 inches, and stroke 5 + 1/8 inches; the normal rate of revolution is 1,350 per minute, and the + reducing gear gives one revolution of the propeller shaft to 1.52 + revolutions of crankshaft. Fuel consumption is 0.48lbs. of fuel per brake + horse-power hour at full load, and oil consumption is 0.020 lbs. per brake + horsepower hour. The dry weight of the engine, complete with propeller + boss, carburettors, and induction pipes, is 850 lbs., and the gross weight + in running order, with fuel and oil for six hours working, is 2,671 lbs., + exclusive of cooling water. + </p> + <p> + To this engine belongs an altitude record of 30,500 feet, made at + Martlesham, near Ipswich, on January 2nd, 1919, by Captain Lang, R.A.F., + the climb being accomplished in 66 minutes 15 seconds. Previous to this, + the altitude record was held by an Italian pilot, who made 25,800 feet in + an hour and 57 minutes in 1916. Lang's climb was stopped through the + pressure of air, at the altitude he reached, being insufficient for + driving the small propellers on the machine which worked the petrol and + oil pumps, or he might have made the height said to have been attained by + Major Schroeder on February 27th, 1920, at Dayton, Ohio. Schroeder is said + to have reached an altitude of 36,020 feet on a Napier biplane, and, owing + to failure of the oxygen supply, to have lost consciousness, fallen five + miles, righted his machine when 2,000 feet in the air, and alighted + successfully. Major Schroeder is an American. + </p> + <p> + Turning back a little, and considering other than British design of Vee + and double-Vee or 'Broad arrow' type of engine, the Renault firm from the + earliest days devoted considerable attention to the development of this + type, their air-cooled engines having been notable examples from the + earliest days of heavier-than-air machines. In 1910 they were making three + sizes of eight-cylindered Vee-type engines, and by 1915 they had increased + to the manufacture of five sizes, ranging from 25 to 100 brake + horse-power, the largest of the five sizes having twelve cylinders but + still retaining the air-cooled principle. The De Dion firm, also, made + Vee-type engines in 1914, being represented by an 80 horse-power + eight-cylindered engine, air-cooled, and a 150 horse-power, also of eight + cylinders, water-cooled, running at a normal rate of 1,600 revolutions per + minute. Another notable example of French construction was the Panhard and + Levassor 100 horse-power eight-cylinder Vee engine, developing its rated + power at 1,500 revolutions per minute, and having the—for that time—low + weight of 4.4 lbs. per horse-power. + </p> + <p> + American Vee design has followed the British fairly cclosely; the Curtiss + Company produced originally a 75 horse-power eight-cylinder Vee type + running at 1,200 revolutions per minute, supplementing this with a 170 + horse-power engine running at 1,600 revolutions per minute, and later with + a twelve-cylinder model Vee type, developing 300 horse-power at 1,500 + revolutions per minute, with cylinder bore of 5 inches and stroke of 7 + inches. An exceptional type of American design was the Kemp Vee engine of + 80 horse-power in which the cylinders were cooled by a current of air + obtained from a fan at the forward end of the engine. With cylinders of + 4.25 inches bore and 4.75 inches stroke, the rater power was developed at + 1,150 revolutions per minute, and with the engine complete the weight was + only 4.75 lbs. per horse-power. + </p> + <p> + <a name="link2H_4_0041" id="link2H_4_0041"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + III. THE RADIAL TYPE + </h2> + <p> + The very first successful design of internal combustion aero engine made + was that of Charles Manly, who built a five-cylinder radial engine in 1901 + for use with Langley's 'aerodrome,' as the latter inventor decided to call + what has since become known as the aeroplane. Manly made a number of + experiments, and finally decided on radial design, in which the cylinders + are so rayed round a central crank-pin that the pistons act successively + upon it; by this arrangement a very short and compact engine is obtained, + with a minimum of weight, and a regular crankshaft rotation and perfect + balance of inertia forces. + </p> + <p> + When Manly designed his radial engine, high speed internal combustion + engines were in their infancy, and the difficulties in construction can be + partly realised when the lack of manufacturing methods for this high-class + engine work, and the lack of experimental data on the various materials, + are taken into account. During its tests, Manly's engine developed 52.4 + brake horsepower at a speed of 950 revolutions per minute, with the + remarkably low weight of only 2.4 lbs. per horsepower; this latter was + increased to 3.6 lbs. when the engine was completed by the addition of + ignition system, radiator, petrol tank, and all accessories, together with + the cooling water for the cylinders. + </p> + <p> + In Manly's engine, the cylinders were of steel, machined outside and + inside to 1/16 of an inch thickness; on the side of cylinder, at the top + end, the valve chamber was brazed, being machined from a solid forging, + The casing which formed the water-jacket was of sheet steel, 1/50 of an + inch in thickness, and this also was brazed on the cylinder and to the + valve chamber. Automatic inlet valves were fitted, and the exhaust valves + were operated by a cam which had two points, 180 degrees apart; the cam + was rotated in the opposite direction to the engine at one-quarter engine + speed. Ignition was obtained by using a one-spark coil and vibrator for + all cylinders, with a distributor to select the right cylinder for each + spark—this was before the days of the high-tension magneto and the + almost perfect ignition systems that makers now employ. The scheme of + ignition for this engine was originated by Manly himself, and he also + designed the sparking plugs fitted in the tops of the cylinders. Through + fear of trouble resulting if the steel pistons worked on the steel + cylinders, cast iron liners were introduced in the latter, 1/16 of an inch + thick. + </p> + <p> + The connecting rods of this engine were of virtually the same type as is + employed on nearly all modern radial engines. The rod for one cylinder had + a bearing along the whole of the crank pin, and its end enclosed the pin; + the other four rods had bearings upon the end of the first rod, and did + not touch the crank pin. The accompanying diagram shows this construction, + together with the means employed for securing the ends of the four rods—the + collars were placed in position after the rods had been put on. The + bearings of these rods did not receive any of the rubbing effect due to + the rotation of the crank pin, the rubbing on them being only that of the + small angular displacement of the rods during each revolution; thus there + was no difficulty experienced with the lubrication. + </p> + <p> + Another early example of the radial type of engine was the French Anzani, + of which type one was fitted to the machine with which Bleriot first + crossed the English Channel—this was of 25 horse-power. The earliest + Anzani engines were of the three-cylinder fan type, one cylinder being + vertical, and the other two placed at an angle of 72 degrees on each side, + as the possibility of over-lubrication of the bottom cylinders was feared + if a regular radial construction were adopted. In order to overcome the + unequal balance of this type, balance weights were fitted inside the crank + case. + </p> + <p> + The final development of this three-cylinder radial was the 'Y' type of + engine, in which the cylinders were regularly disposed at 120 degrees + apart, the bore was 4.1, stroke 4.7 inches, and the power developed was 30 + brake horse-power at 1,300 revolutions per minute. + </p> + <p> + Critchley's list of aero engines being constructed in 1910 shows twelve of + the radial type, with powers of between 14 and 100 horse-power, and with + from three to ten cylinder—this last is probably the greatest number + of cylinders that can be successfully arranged in circular form. Of the + twelve types of 1910, only two were water-cooled, and it is to be noted + that these two ran at the slowest speeds and had the lowest weight per + horse-power of any. + </p> + <p> + The Anzani radial was considerably developed special attention being paid + to this type by its makers and by 1914 the Anzani list comprised seven + different sizes of air-cooled radials. Of these the largest had twenty + cylinders, developing 200 brake horse-power—it was virtually a + double radial—and the smallest was the original 30 horse-power + three-cylinder design. A six-cylinder model was formed by a combination of + two groups of three cylinders each, acting upon a double-throw crankshaft; + the two crank pins were set at 180 degrees to each other, and the cylinder + groups were staggered by an amount equal to the distance between the + centres of the crank pins. Ten-cylinder radial engines are made with two + groups of five cylinders acting upon two crank pins set at 180 degrees to + each other, the largest Anzani 'ten' developed 125 horsepower at 1,200 + revolutions per minute, the ten cylinders being each 4.5 inches in bore + with stroke of 5.9 inches, and the weight of the engine being 3.7 lbs. per + horse-power. In the 200 horse-power Anzani radial the cylinders are + arranged in four groups of five each, acting on two crank pins. The bore + of the cylinders in this engine is the same as in the three-cylinder, but + the stroke is increased to 5.5 inches. The rated power is developed at + 1,300 revolutions per minute, and the engine complete weighs 3.4 lbs. per + horse-power. + </p> + <p> + With this 200 horse-power Anzani, a petrol consumption of as low as 0.49 + lbs. of fuel per brake horse-power per hour has been obtained, but the + consumption of lubricating oil is compensatingly high, being up to + one-fifth of the fuel used. The cylinders are set desaxe with the crank + shaft, and are of cast-iron, provided with radiating ribs for air-cooling; + they are attached to the crank case by long bolts passing through bosses + at the top of the cylinders, and connected to other bolts at right angles + through the crank case. The tops of the cylinders are formed flat, and + seats for the inlet and exhaust valves are formed on them. The pistons are + cast-iron, fitted with ordinary cast-iron spring rings. An aluminium crank + case is used, being made in two halves connected together by bolts, which + latter also attach the engine to the frame of the machine. The crankshaft + is of nickel steel, made hollow, and mounted on ball-bearings in such a + manner that practically a combination of ball and plain bearings is + obtained; the central web of the shaft is bent to bring the centres of the + crank pins as close together as possible, leaving only room for the + connecting rods, and the pins are 180 degrees apart. Nickel steel valves + of the cone-seated, poppet type are fitted, the inlet valves being + automatic, and those for the exhaust cam-operated by means of push-rods. + With an engine having such a number of cylinders a very uniform rotation + of the crankshaft is obtained, and in actual running there are always five + of the cylinders giving impulses to the crankshaft at the same time. + </p> + <p> + An interesting type of pioneer radial engine was the Farcot, in which the + cylinders were arranged in a horizontal plane, with a vertical crankshaft + which operated the air-screw through bevel gearing. This was an + eight-cylinder engine, developing 64 horse-power at 1,200 revolutions per + minute. The R.E.P. type,in the early days, was a 'fan' engine, but the + designer, M. Robert Pelterie, turned from this design to a seven-cylinder + radial, which at 1,100 revolutions per minute gave 95 horse-power. Several + makers entered into radial engine development in the years immediately + preceding the War, and in 1914 there were some twenty-two different sizes + and types, ranging from 30 to 600 horse-power, being made, according to + report; the actual construction of the latter size at this time, however, + is doubtful. + </p> + <p> + Probably the best example of radial construction up to the outbreak of War + was the Salmson (Canton-Unne) water-cooled, of which in 1914 six sizes + were listed as available. Of these the smallest was a seven-cylinder 90 + horse-power engine, and the largest, rated at 600 horse-power, had + eighteen cylinders. These engines, during the War, were made under license + by the Dudbridge Ironworks in Great Britain. + </p> + <p> + The accompanying diagram shows the construction of the cylinders in the + 200 horse-power size, showing the method of cooling, and the arrangement + of the connecting rods. A patent planetary gear, also shown in the + diagram, gives exactly the same stroke to all the pistons. The complete + engine has fourteen cylinders, of forged steel machined all over, and so + secured to the crank case that any one can be removed without parting the + crank case. The water-jackets are of spun copper, brazed on to the + cylinder, and corrugated so as to admit of free expansion; the water is + circulated by means of a centrifugal pump. The pistons are of cast-iron, + each fitted with three rings, and the connecting rods are of high grade + steel, machined all over and fitted with bushes of phosphor bronze; these + rods are connected to a central collar, carried on the crank pin by two + ball-bearings. The crankshaft has a single throw, and is made in two parts + to allow the cage for carrying the big end-pins of the connecting rods to + be placed in position. + </p> + <p> + The casing is in two parts, on one of which the brackets for fixing the + engine are carried, while the other part carries the valve-gear. Bolts + secure the two parts together. The mechanically-operated steel valves on + the cylinders are each fitted with double springs and the valves are + operated by rods and levers. Two Zenith carburettors are fitted on the + rear half of the crank case, and short induction pipes are led to each + cylinder; each of the carburettors is heated by the exhaust gases. + Ignition is by two high-tension magnetos, and a compressed air + self-starting arrangement is provided. Two oil pumps are fitted for + lubricating purposes, one of which forces oil to the crankshaft and + connecting-rod bearings, while the second forces oil to the valve gear, + the cylinders being so arranged that the oil which flows along the walls + cannot flood the lower cylinders. This engine operates upon a six-stroke + cycle, a rather rare arrangement for internal combustion engines of the + electrical ignition type; this is done in order to obtain equal angular + intervals for the working impulses imparted to the rotating crankshaft, as + the cylinders are arranged in groups of seven, and all act upon the one + crankshaft. The angle, therefore, between the impulses is 77 1/7 degrees. + A diagram is inset giving a side view of the engine, in order to show the + grouping of the cylinders. + </p> + <p> + The 600 horse-power Salmson engine was designed with a view to fitting to + airships, and was in reality two nine-cylindered engines, with a gear-box + connecting them; double air-screws were fitted, and these were so arranged + that either or both of them might be driven by either or both engines; in + addition to this, the two engines were complete and separate engines as + regards carburation and ignition, etc., so that they could be run + independently of each other. The cylinders were exceptionally 'long + stroke,' being 5.9 inches bore to 8.27 inches stroke, and the rated power + was developed at 1,200 revolutions per minute, the weight of the complete + engine being only 4.1 lbs. per horse-power at the normal rating. + </p> + <p> + A type of engine specially devised for airship propulsion is that in which + the cylinders are arranged horizontally instead of vertically, the main + advantages of this form being the reduction of head resistance and less + obstruction to the view of the pilot. A casing, mounted on the top of the + engine, supports the air-screw, which is driven through bevel gearing from + the upper end of the crankshaft. With this type of engine a better rate of + air-screw efficiency is obtained by gearing the screw down to half the + rate of revolution of the engine, this giving a more even torque. The + petrol consumption of the type is very low, being only 0.48 lbs. per + horse-power per hour, and equal economy is claimed as regards lubricating + oil, a consumption of as little as 0.04 lbs. per horse-power per hour + being claimed. + </p> + <p> + Certain American radial engines were made previous to 1914, the principal + being the Albatross six-cylinder engines of 50 and 100 horse-powers. Of + these the smaller size was air-cooled, with cylinders of 4.5 inches bore + and 5 inches stroke, developing the rated power at 1,230 revolutions per + minute, with a weight of about 5 lbs. per horse-power. The 100 horse-power + size had cylinders of 5.5 inches bore, developing its rated power at 1,230 + revolutions per minute, and weighing only 2.75 lbs. per horse-power. This + engine was markedly similar to the six-cylindered Anzani, having all the + valves mechanically operated, and with auxiliary exhaust ports at the + bottoms of the cylinders, overrun by long pistons. These Albatross engines + had their cylinders arranged in two groups of three, with each group of + three pistons operating on one of two crank pins, each 180 degrees apart. + </p> + <p> + The radial type of engine, thanks to Charles Manly, had the honour of + being first in the field as regards aero work. Its many advantages, among + which may be specially noted the very short crankshaft as compared with + vertical, Vee, or 'broad arrow' type of engine, and consequent greater + rigidity, ensure it consideration by designers of to-day, and render it + certain that the type will endure. Enthusiasts claim that the 'broad + arrow' type, or Vee with a third row of cylinders inset between the + original two, is just as much a development from the radial engine as from + the vertical and resulting Vee; however this may be, there is a place for + the radial type in air-work for as long as the internal combustion engine + remains as a power plant. + </p> + <p> + <a name="link2H_4_0042" id="link2H_4_0042"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + IV. THE ROTARY TYPE + </h2> + <p> + M. Laurent Seguin, the inventor of the Gnome rotary aero engine, provided + as great a stimulus to aviation as any that was given anterior to the war + period, and brought about a great advance in mechanical flight, since + these well-made engines gave a high-power output for their weight, and + were extremely smooth in running. In the rotary design the crankshaft of + the engine is stationary, and the cylinders, crank case, and all their + adherent parts rotate; the working is thus exactly opposite in principle + to that of the radial type of aero engine, and the advantage of the rotary + lies in the considerable flywheel effect produced by the revolving + cylinders, with consequent evenness of torque. Another advantage is that + air-cooling, adopted in all the Gnome engines, is rendered much more + effective by the rotation of the cylinders, though there is a tendency to + distortion through the leading side of each cylinder being more + efficiently cooled than the opposite side; advocates of other types are + prone to claim that the air resistance to the revolving cylinders absorbs + some 10 per cent of the power developed by the rotary engine, but that has + not prevented the rotary from attaining to great popularity as a prime + mover. + </p> + <p> + There were, in the list of aero engines compiled in 1910, five rotary + engines included, all air-cooled. Three of these were Gnome engines, and + two of the make known as 'International.' They ranged from 21.5 to 123 + horse-power, the latter being rated at only 1.8 lbs. weight per brake + horse-power, and having fourteen cylinders, 4.33 inches in diameter by 4.7 + inches stroke. By 1914 forty-three different sizes and types of rotary + engine were being constructed, and in 1913 five rotary type engines were + entered for the series of aeroplane engine trials held in Germany. Minor + defects ruled out four of these, and only the German Bayerischer Motoren + Flugzeugwerke completed the seven-hour test prescribed for competing + engines. Its large fuel consumption barred this engine from the final + trials, the consumption being some 0.95 pints per horse-power per hour. + The consumption of lubricating oil, also was excessive, standing at 0.123 + pint per horse-power per hour. The engine gave 37.5 effective horse-power + during its trial, and the loss due to air resistance was 4.6 horse-power, + about 11 per cent. The accompanying drawing shows the construction of the + engine, in which the seven cylinders are arranged radially on the crank + case; the method of connecting the pistons to the crank pins can be seen. + The mixture is drawn through the crank chamber, and to enter the cylinder + it passes through the two automatic valves in the crown of the piston; the + exhaust valves are situated in the tops of the cylinders, and are actuated + by cams and push-rods. Cooling of the cylinder is assisted by the radial + rings, and the diameter of these rings is increased round the hottest part + of the cylinder. When long flights are undertaken the advantage of the + light weight of this engine is more than counterbalanced by its high fuel + and lubricating oil consumption, but there are other makes which are much + better than this seven-cylinder German in respect of this. + </p> + <p> + Rotation of the cylinders in engines of this type is produced by the side + pressure of the pistons on the cylinder walls, and in order to prevent + this pressure from becoming abnormally large it is necessary to keep the + weight of the piston as low as possible, as the pressure is produced by + the tangential acceleration and retardation of the piston. On the upward + stroke the circumferential velocity of the piston is rapidly increased, + which causes it to exert a considerable tangential pressure on the side of + the cylinder, and on the return stroke there is a corresponding retarding + effect due to the reduction of the circumferential velocity of the piston. + These side pressures cause an appreciable increase in the temperatures of + the cylinders and pistons, which makes it necessary to keep the power + rating of the engines fairly low. + </p> + <p> + Seguin designed his first Gnome rotary as a 34 horse-power engine when run + at a speed of 1,300 revolutions per minute. It had five cylinders, and the + weight was 3.9 lbs. per horse-power. A seven-cylinder model soon displaced + this first engine, and this latter, with a total weight of 165 lbs., gave + 61.5 horse-power. The cylinders were machined out of solid nickel + chrome-steel ingots, and the machining was carried out so that the + cylinder walls were under 1/6 of an inch in thickness. The pistons were + cast-iron, fitted each with two rings, and the automatic inlet valve to + the cylinder was placed in the crown of the piston. The connecting rods, + of 'H' section, were of nickel chrome-steel, and the large end of one rod, + known as the 'master-rod' embraced the crank pin; on the end of this rod + six hollow steel pins were carried, and to these the remaining six + connecting-rods were attached. The crankshaft of the engine was made of + nickel chrome-steel, and was in two parts connected together at the crank + pin; these two parts, after the master-rod had been placed in position and + the other connecting rods had been attached to it, were firmly secured. + The steel crank case was made in five parts, the two central ones holding + the cylinders in place, and on one side another of the five castings + formed a cam-box, to the outside of which was secured the extension to + which the air-screw was attached. On the other side of the crank case + another casting carried the thrust-box, and the whole crank case, with its + cylinders and gear, was carried on the fixed crank shaft by means of four + ball-bearings, one of which also took the axial thrust of the air-screw. + </p> + <p> + For these engines, castor oil is the lubricant usually adopted, and it is + pumped to the crankshaft by means of a gear-driven oil pump; from this + shaft the other parts of the engine are lubricated by means of centrifugal + force, and in actual practice sufficient unburnt oil passes through the + cylinders to lubricate the exhaust valve, which partly accounts for the + high rate of consumption of lubricating oil. A very simple carburettor of + the float less, single-spray type was used, and the mixture was passed + along the hollow crankshaft to the interior of the crank case, thence + through the automatic inlet valves in the tops of the pistons to the + combustion chambers of the cylinders. Ignition was by means of a + high-tension magneto specially geared to give the correct timing, and the + working impulses occurred at equal angular intervals of 102.85 degrees. + The ignition was timed so that the firing spark occurred when the cylinder + was 26 degrees before the position in which the piston was at the outer + end of its stroke, and this timing gave a maximum pressure in the cylinder + just after the piston had passed this position. + </p> + <p> + By 1913, eight different sizes of the Gnome engine were being constructed, + ranging from 45 to 180 brake horse-power; four of these were single-crank + engines one having nine and the other three having seven cylinders. The + remaining four were constructed with two cranks; three of them had + fourteen cylinders apiece, ranged in groups of seven, acting on the + cranks, and the one other had eighteen cylinders ranged in two groups of + nine, acting on its two cranks. Cylinders of the two-crank engines are so + arranged (in the fourteen-cylinder type) that fourteen equal angular + impulses occur during each cycle; these engines are supported on bearings + on both sides of the engine, the air-screw being placed outside the front + support. In the eighteen-cylinder model the impulses occur at each 40 + degrees of angular rotation of the cylinders, securing an extremely even + rotation of the air-screw. + </p> + <p> + In 1913 the Gnome Monosoupape engine was introduced, a model in which the + inlet valve to the cylinder was omitted, while the piston was of the + ordinary cast-iron type. A single exhaust valve in the cylinder head was + operated in a manner similar to that on the previous Gnome engines, and + the fact of this being the only valve on the cylinder gave the engine its + name. Each cylinder contained ports at the bottom which communicated with + the crank chamber, and were overrun by the piston when this was + approaching the bottom end of its stroke. During the working cycle of the + engine the exhaust valve was opened early to allow the exhaust gases to + escape from the cylinder, so that by the time the piston overran the ports + at the bottom the pressure within the cylinder was approximately equal to + that in the crank case, and practically no flow of gas took place in + either direction through the ports. The exhaust valve remained open as + usual during the succeeding up-stroke of the piston, and the valve was + held open until the piston had returned through about one-third of its + downward stroke, thus permitting fresh air to enter the cylinder. The + exhaust valve then closed, and the downward motion of the piston, + continuing, caused a partial vacuum inside the cylinder; when the piston + overran the ports, the rich mixture from the crank case immediately + entered. The cylinder was then full of the mixture, and the next upward + stroke of the piston compressed the charge; upon ignition the working + cycle was repeated. The speed variation of this engine was obtained by + varying the extent and duration of the opening of the exhaust valves, and + was controlled by the pilot by hand-operated levers acting on the valve + tappet rollers. The weight per horsepower of these engines was slightly + less than that of the two-valve type, while the lubrication of the gudgeon + pin and piston showed an improvement, so that a lower lubricating oil + consumption was obtained. The 100 horse-power Gnome Monosoupape was built + with nine cylinders, each 4.33 inches bore by 5.9 inches stroke, and it + developed its rated power at 1,200 revolutions per minute. + </p> + <p> + An engine of the rotary type, almost as well known as the Gnome, is the + Clerget, in which both cylinders and crank case are made of steel, the + former having the usual radial fins for cooling. In this type the inlet + and exhaust valves are both located in the cylinder head, and mechanically + operated by push-rods and rockers. Pipes are carried from the crank case + to the inlet valve casings to convey the mixture to the cylinders, a + carburettor of the central needle type being used. The carburetted mixture + is taken into the crank case chamber in a manner similar to that of the + Gnome engine. Pistons of aluminium alloy, with three cast-iron rings, are + fitted, the top ring being of the obturator type. The large end of one of + the nine connecting rods embraces the crank pin and the pressure is taken + on two ball-bearings housed in the end of the rod. This carries eight + pins, to which the other rods are attached, and the main rod being rigid + between the crank pin and piston pin determines the position of the + pistons. Hollow connecting-rods are used, and the lubricating oil for the + piston pins passes from the crankshaft through the centres of the rods. + Inlet and exhaust valves can be set quite independently of one another—a + useful point, since the correct timing of the opening of these valves is + of importance. The inlet valve opens 4 degrees from top centre and closes + after the bottom dead centre of the piston; the exhaust valve opens 68 + degrees before the bottom centre and closes 4 degrees after the top dead + centre of the piston. The magnetos are set to give the spark in the + cylinder at 25 degrees before the end of the compression stroke—two + high-tension magnetos are used: if desired, the second one can be adjusted + to give a later spark for assisting the starting of the engine. The + lubricating oil pump is of the valveless two-plunger type, so geared that + it runs at seven revolutions to 100 revolutions of the engine; by counting + the pulsations the speed of the engine can be quickly calculated by + multiplying the pulsations by 100 and dividing by seven. In the 115 + horse-power nine-cylinder Clerget the cylinders are 4.7 bore with a 6.3 + inches stroke, and the rated power of the engine is obtained at 1,200 + revolutions per minute. The petrol consumption is 0.75 pint per + horse-power per hour. + </p> + <p> + A third rotary aero engine, equally well known with the foregoing two, is + the Le Rhone, made in four different sizes with power outputs of from 50 + to 160 horse-power; the two smaller sizes are single crank engines with + seven and nine cylinders respectively, and the larger sizes are of + double-crank design, being merely the two smaller sizes doubled—fourteen + and eighteen-cylinder engines. The inlet and exhaust valves are located in + the cylinder head, and both valves are mechanically operated by one + push-rod and rocker, radial pipes from crank case to inlet valve casing + taking the mixture to the cylinders. The exhaust valves are placed on the + leading, or air-screw side, of the engine, in order to get the fullest + possible cooling effect. The rated power of each type of engine is + obtained at 1,200 revolutions per minute, and for all four sizes the + cylinder bore is 4.13 inches, with a 5.5 inches piston stroke. Thin + cast-iron liners are shrunk into the steel cylinders in order to reduce + the amount of piston friction. Although the Le Rhone engines are + constructed practically throughout of steel, the weight is only 2.9 lbs. + per horse-power in the eighteen-cylinder type. + </p> + <p> + American enterprise in the construction of the rotary type is perhaps best + illustrated in the 'Gyro 'engine; this was first constructed with inlet + valves in the heads of the pistons, after the Gnome pattern, the exhaust + valves being in the heads of the cylinders. The inlet valve in the crown + of each piston was mechanically operated in a very ingenious manner by the + oscillation of the connecting-rod. The Gyro-Duplex engine superseded this + original design, and a small cross-section illustration of this is + appended. It is constructed in seven and nine-cylinder sizes, with a power + range of from 50 to 100 horse-power; with the largest size the low weight + of 2.5 lbs.. per horse-power is reached. The design is of considerable + interest to the internal combustion engineer, for it embodies a piston + valve for controlling auxiliary exhaust ports, which also acts as the + inlet valve to the cylinder. The piston uncovers the auxiliary ports when + it reaches the bottom of its stroke, and at the end of the power stroke + the piston is in such a position that the exhaust can escape over the top + of it. The exhaust valve in the cylinder head is then opened by means of + the push-rod and rocker, and is held open until the piston has completed + its upward stroke and returned through more than half its subsequent + return stroke. When the exhaust valve closes, the cylinder has a charge of + fresh air, drawn in through the exhaust valve, and the further motion of + the piston causes a partial vacuum; by the time the piston reaches bottom + dead centre the piston-valve has moved up to give communication between + the cylinder and the crank case, therefore the mixture is drawn into the + cylinder. Both the piston valve and exhaust valve are operated by cams + formed on the one casting, which rotates at seven-eighths engine speed for + the seven-cylinder type, and nine-tenths engine speed for the + nine-cylinder engines. Each of these cams has four or five points + respectively, to suit the number of cylinders. + </p> + <p> + The steel cylinders are machined from solid forgings and provided with + webs for air-cooling as shown. Cast-iron pistons are used, and are + connected to the crankshaft in the same manner as with the Gnome and Le + Rhone engines. Petrol is sprayed into the crank case by a small geared + pump and the mixture is taken from there to the piston valves by radial + pipes. Two separate pumps are used for lubrication, one forcing oil to the + crank-pin bearing and the other spraying the cylinders. + </p> + <p> + Among other designs of rotary aero engines the E.J.C. is noteworthy, in + that the cylinders and crank case of this engine rotate in opposite + directions, and two air-screws are used, one being attached to the end of + the crankshaft, and the other to the crank case. Another interesting type + is the Burlat rotary, in which both the cylinders and crankshaft rotate in + the same direction, the rotation of the crankshaft being twice that of the + cylinders as regards speed. This engine is arranged to work on the + four-stroke cycle with the crankshaft making four, and the cylinders two, + revolutions per cycle. + </p> + <p> + It would appear that the rotary type of engine is capable of but little + more improvement—save for such devices as these of the last two + engines mentioned, there is little that Laurent Seguin has not already + done in the Gnome type. The limitation of the rotary lies in its high fuel + and lubricating oil consumption, which renders it unsuited for + long-distance aero work; it was, in the war period, an admirable engine + for such short runs as might be involved in patrol work 'over the lines,' + and for similar purposes, but the watercooled Vee or even vertical, with + its much lower fuel consumption, was and is to be preferred for distance + work. The rotary air-cooled type has its uses, and for them it will + probably remain among the range of current types for some time to come. + Experience of matters aeronautical is sufficient to show, however, that + prophecy in any direction is most unsafe. + </p> + <p> + <a name="link2H_4_0043" id="link2H_4_0043"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + V. THE HORIZONTALLY-OPPOSED ENGINE + </h2> + <p> + Among the first internal combustion engines to be taken into use with + aircraft were those of the horizontally-opposed four-stroke cycle type, + and, in every case in which these engines were used, their excellent + balance and extremely even torque rendered them ideal-until the tremendous + increase in power requirements rendered the type too long and bulky for + placing in the fuselage of an aeroplane. As power increased, there came a + tendency toward placing cylinders radially round a central crankshaft, + and, as in the case of the early Anzani, it may be said that the radial + engine grew out of the horizontal opposed piston type. There were, in 1910—that + is, in the early days of small power units, ten different sizes of the + horizontally opposed engine listed for manufacture, but increase in power + requirements practically ruled out the type for air work. + </p> + <p> + The Darracq firm were the leading makers of these engines in 1910; their + smallest size was a 24 horsepower engine, with two cylinders each of 5.1 + inches bore by 4.7 inches stroke. This engine developed its rated power at + 1,500 revolutions per minute, and worked out at a weight of 5 lbs. per + horse-power. With these engines the cranks are so placed that two regular + impulses are given to the crankshaft for each cycle of working, an + arrangement which permits of very even balancing of the inertia forces of + the engine. The Darracq firm also made a four-cylindered horizontal + opposed piston engine, in which two revolutions were given to the + crankshaft per revolution, at equal angular intervals. + </p> + <p> + The Dutheil-Chambers was another engine of this type, and had the + distinction of being the second largest constructed. At 1,000 revolutions + per minute it developed 97 horse-power; its four cylinders were each of + 4.93 inches bore by 11.8 inches stroke—an abnormally long stroke in + comparison with the bore. The weight—which owing to the build of the + engine and its length of stroke was bound to be rather high, actually + amounted to 8.2 lbs. per horse-power. Water cooling was adopted, and the + engine was, like the Darracq four-cylinder type, so arranged as to give + two impulses per revolution at equal angular intervals of crankshaft + rotation. + </p> + <p> + One of the first engines of this type to be constructed in England was the + Alvaston, a water-cooled model which was made in 20, 30, and 50 brake + horse-power sizes, the largest being a four-cylinder engine. All three + sizes were constructed to run at 1,200 revolutions per minute. In this + make the cylinders were secured to the crank case by means of four long + tie bolts passing through bridge pieces arranged across the cylinder + heads, thus relieving the cylinder walls of all longitudinal explosion + stresses. These bridge pieces were formed from chrome vanadium steel and + milled to an 'H' section, and the bearings for the valve-tappet were + forged solid with them. Special attention was given to the machining of + the interiors of the cylinders and the combustion heads, with the result + that the exceptionally high compression of 95 lbs. per square inch was + obtained, giving a very flexible engine. The cylinder heads were + completely water-jacketed, and copper water-jackets were also fitted round + the cylinders. The mechanically operated valves were actuated by specially + shaped cams, and were so arranged that only two cams were required for the + set of eight valves. The inlet valves at both ends of the engine were + connected by a single feed-pipe to which the carburettor was attached, the + induction piping being arranged above the engine in an easily accessible + position. Auxiliary air ports were provided in the cylinder walls so that + the pistons overran them at the end of their stroke. A single vertical + shaft running in ball-bearings operated the valves and water circulating + pump, being driven by spiral gearing from the crankshaft at half speed. In + addition to the excellent balance obtained with this engine, the makers + claimed with justice that the number of working parts was reduced to an + absolute minimum. + </p> + <p> + In the two-cylinder Darracq, the steel cylinders were machined from solid, + and auxiliary exhaust ports, overrun by the piston at the inner end of its + stroke, were provided in the cylinder walls, consisting of a circular row + of drilled holes—this arrangement was subsequently adopted on some + of the Darracq racing car engines. The water jackets were of copper, + soldered to the cylinder walls; both the inlet and exhaust valves were + located in the cylinder heads, being operated by rockers and push-rods + actuated by cams on the halftime shaft driven from one end of the + crankshaft. Ignition was by means of a high-tension magneto, and long + induction pipes connected the-ends of the cylinders to the carburettor, + the latter being placed underneath the engine. Lubrication was effected by + spraying oil into the crank case by means of a pump, and a second pump + circulated the cooling water. + </p> + <p> + Another good example of this type of engine was the Eole, which had eight + opposed pistons, each pair of which was actuated by a common combustion + chamber at the centre of the engine, two crankshafts being placed at the + outer ends of the engine. This reversal of the ordinary arrangement had + two advantages; it simplified induction, and further obviated the need for + cylinder heads, since the explosion drove at two piston heads instead of + at one piston head and the top of the cylinder; against this, however, the + engine had to be constructed strongly enough to withstand the longitudinal + stresses due to the explosions, as the cranks are placed on the outer ends + and the cylinders and crank-cases take the full force of each explosion. + Each crankshaft drove a separate air-screw. + </p> + <p> + This pattern of engine was taken up by the Dutheil-Chambers firm in the + pioneer days of aircraft, when the firm in question produced seven + different sizes of horizontal engines. The Demoiselle monoplane used by + Santos-Dumont in 1909 was fitted with a two-cylinder, horizontally-opposed + Dutheil-Chambers engine, which developed 25 brake horse-power at a speed + of 1,100 revolutions per minute, the cylinders being of 5 inches bore by + 5.1 inches stroke, and the total weight of the engine being some 120 lbs. + The crankshafts of these engines were usually fitted with steel flywheels + in order to give a very even torque, the wheels being specially + constructed with wire spokes. In all the Dutheil-Chambers engines water + cooling was adopted, and the cylinders were attached to the crank cases by + means of long bolts passing through the combustion heads. + </p> + <p> + For their earliest machines, the Clement-Bayard firm constructed + horizontal engines of the opposed piston type. The best known of these was + the 30 horse-power size, which had cylinders of 4.7 inches diameter by 5.1 + inches stroke, and gave its rated power at 1,200 revolutions per minute. + In this engine the steel cylinders were secured to the crank case by + flanges, and radiating ribs were formed around the barrel to assist the + air-cooling. Inlet and exhaust valves were actuated by push-rods and + rockers actuated from the second motion shaft mounted above the crank + case; this shaft also drove the high-tension magneto with which the engine + was fitted. A ring of holes drilled round each cylinder constituted + auxiliary ports which the piston uncovered at the inner end of its stroke, + and these were of considerable assistance not only in expelling exhaust + gases, but also in moderating the temperature of the cylinder and of the + main exhaust valve fitted in the cylinder head. A water-cooled + Clement-Bayard horizontal engine was also made, and in this the auxiliary + exhaust ports were not embodied; except in this particular, the engine was + very similar to the water-cooled Darracq. + </p> + <p> + The American Ashmusen horizontal engine, developing 100 horse-power, is + probably the largest example of this type constructed. It was made with + six cylinders arranged on each side of a common crank case, with long + bolts passing through the cylinder heads to assist in holding them down. + The induction piping and valve-operating gear were arranged below the + engine, and the half-speed shaft carried the air-screw. + </p> + <p> + Messrs Palons and Beuse, Germans, constructed a light-weight, air-cooled, + horizontally-opposed engine, two-cylindered. In this the cast-iron + cylinders were made very thin, and were secured to the crank case by bolts + passing through lugs cast on the outer ends of the cylinders; the + crankshaft was made hollow, and holes were drilled through the webs of the + connecting-rods in order to reduce the weight. The valves were fitted to + the cylinder heads, the inlet valves being of the automatic type, while + the exhaust valves were mechanically operated from the cam-shaft by means + of rockers and push-rods. Two carburettors were fitted, to reduce the + induction piping to a minimum; one was attached to each combustion + chamber, and ignition was by the normal high-tension magneto driven from + the halftime shaft. + </p> + <p> + There was also a Nieuport two-cylinder air-cooled horizontal engine, + developing 35 horse-power when running at 1,300 revolutions per minute, + and being built at a weight of 5.1 lbs. per horse-power. The cylinders + were of 5.3 inches diameter by 5.9 inches stroke; the engine followed the + lines of the Darracq and Dutheil-Chambers pretty closely, and thus calls + for no special description. + </p> + <p> + The French Kolb-Danvin engine of the horizontal type, first constructed in + 1905, was probably the first two-stroke cycle engine designed to be + applied to the propulsion of aircraft; it never got beyond the + experimental stage, although its trials gave very good results. Stepped + pistons were adopted, and the charging pump at one end was used to + scavenge the power cylinder at the other ends of the engine, the transfer + ports being formed in the main casting. The openings of these ports were + controlled at both ends by the pistons, and the location of the ports + appears to have made it necessary to take the exhaust from the bottom of + one cylinder and from the top of the other. The carburetted mixture was + drawn into the scavenging cylinders, and the usual deflectors were cast on + the piston heads to assist in the scavenging and to prevent the fresh gas + from passing out of the exhaust ports. + </p> + <p> + <a name="link2H_4_0044" id="link2H_4_0044"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + VI. THE TWO-STROKE CYCLE ENGINE + </h2> + <p> + Although it has been little used for aircraft propulsion, the + possibilities of the two-stroke cycle engine render some study of it + desirable in this brief review of the various types of internal combustion + engine applicable both to aeroplanes and airships. Theoretically the + two-stroke cycle engine—or as it is more commonly termed, the + 'two-stroke,' is the ideal power producer; the doubling of impulses per + revolution of the crankshaft should render it of very much more even + torque than the four-stroke cycle types, while, theoretically, there + should be a considerable saving of fuel, owing to the doubling of the + number of power strokes per total of piston strokes. In practice, however, + the inefficient scavenging of virtually every two-stroke cycle engine + produced nullifies or more than nullifies its advantages over the + four-stroke cycle engine; in many types, too, there is a waste of fuel + gases through the exhaust ports, and much has yet to be done in the way of + experiment and resulting design before the two-stroke cycle engine can be + regarded as equally reliable, economical, and powerful with its elder + brother. + </p> + <p> + The first commercially successful engine operating on the two-stroke cycle + was invented by Mr Dugald Clerk, who in 1881 proved the design feasible. + As is more or less generally understood, the exhaust gases of this engine + are discharged from the cylinder during the time that the piston is + passing the inner dead centre, and the compression, combustion, and + expansion of the charge take place in similar manner to that of the + four-stroke cycle engine. The exhaust period is usually controlled by the + piston overrunning ports in the cylinder at the end of its working stroke, + these ports communicating direct with the outer air—the complication + of an exhaust valve is thus obviated; immediately after the escape of the + exhaust gases, charging of the cylinder occurs, and the fresh gas may be + introduced either through a valve in the cylinder head or through ports + situated diametrically opposite to the exhaust ports. The continuation of + the outward stroke of the piston, after the exhaust ports have been + closed, compresses the charge into the combustion chamber of the cylinder, + and the ignition of the mixture produces a recurrence of the working + stroke. + </p> + <p> + Thus, theoretically, is obtained the maximum of energy with the minimum of + expenditure; in practice, however, the scavenging of the power cylinder, a + matter of great importance in all internal combustion engines, is often + imperfect, owing to the opening of the exhaust ports being of relatively + short duration; clearing the exhaust gases out of the cylinder is not + fully accomplished, and these gases mix with the fresh charge and detract + from its efficiency. Similarly, owing to the shorter space of time + allowed, the charging of the cylinder with the fresh mixture is not so + efficient as in the four-stroke cycle type; the fresh charge is usually + compressed slightly in a separate chamber—crank case, independent + cylinder, or charging pump, and is delivered to the working cylinder + during the beginning of the return stroke of the piston, while in engines + working on the four-stroke cycle principle a complete stroke is devoted to + the expulsion of the waste gases of the exhaust, and another full stroke + to recharging the cylinder with fresh explosive mixture. + </p> + <p> + Theoretically the two-stroke and the four-stroke cycle engines possess + exactly the same thermal efficiency, but actually this is modified by a + series of practical conditions which to some extent tend to neutralise the + very strong case in favour of the two-stroke cycle engine. The specific + capacity of the engine operating on the two-stroke principle is + theoretically twice that of one operating on the four-stroke cycle, and + consequently, for equal power, the former should require only about half + the cylinder volume of the latter; and, owing to the greater superficial + area of the smaller cylinder, relatively, the latter should be far more + easily cooled than the larger four-stroke cycle cylinder; thus it should + be possible to get higher compression pressures, which in turn should + result in great economy of working. Also the obtaining of a working + impulse in the cylinder for each revolution of the crankshaft should give + a great advantage in regularity of rotation—which it undoubtedly + does—and the elimination of the operating gear for the valves, inlet + and exhaust, should give greater simplicity of design. + </p> + <p> + In spite of all these theoretical—and some practical—advantages + the four-stroke cycle engine was universally adopted for aircraft work; + owing to the practical equality of the two principles of operation, so far + as thermal efficiency and friction losses are concerned, there is no doubt + that the simplicity of design (in theory) and high power output to weight + ratio (also in theory) ought to have given the 'two-stroke' a place on the + aeroplane. But this engine has to be developed so as to overcome its + inherent drawbacks; better scavenging methods have yet to be devised—for + this is the principal drawback—before the two-stroke can come to its + own as a prime mover for aircraft. + </p> + <p> + Mr Dugald Clerk's original two-stroke cycle engine is indicated roughly, + as regards principle, by the accompanying diagram, from which it will be + seen that the elimination of the ordinary inlet and exhaust valves of the + four-stroke type is more than compensated by a separate cylinder which, + having a piston worked from the connecting-rod of the power cylinder, was + used to charging, drawing the mixture from the carburettor past the valve + in the top of the charging cylinder, and then forcing it through the + connecting pipe into the power cylinder. The inlet valves both on the + charging and the power cylinders are automatic; when the power piston is + near the bottom of its stroke the piston in the charging cylinder is + compressing the carburetted air, so that as soon as the pressure within + the power cylinder is relieved by the exit of the burnt gases through the + exhaust ports the pressure in the charging cylinder causes the valve in + the head of the power cylinder to open, and fresh mixture flows into the + cylinder, replacing the exhaust gases. After the piston has again covered + the exhaust ports the mixture begins to be compressed, thus automatically + closing the inlet valve. Ignition occurs near the end of the compression + stroke, and the working stroke immediately follows, thus giving an impulse + to the crankshaft on every down stroke of the piston. If the scavenging of + the cylinder were complete, and the cylinder were to receive a full charge + of fresh mixture for every stroke, the same mean effective pressure as is + obtained with four-stroke cycle engines ought to be realised, and at an + equal speed of rotation this engine should give twice the power obtainable + from a four-stroke cycle engine of equal dimensions. This result was not + achieved, and, with the improvements in construction brought about by + experiment up to 1912, the output was found to be only about fifty per + cent more than that of a four-stroke cycle engine of the same size, so + that, when the charging cylinder is included, this engine has a greater + weight per horse-power, while the lowest rate of fuel consumption recorded + was 0.68 lb. per horse-power per hour. + </p> + <p> + In 1891 Mr Day invented a two-stroke cycle engine which used the crank + case as a scavenging chamber, and a very large number of these engines + have been built for industrial purposes. The charge of carburetted air is + drawn through a non-return valve into the crank chamber during the + upstroke of the piston, and compressed to about 4 lbs. pressure per square + inch on the down stroke. When the piston approaches the bottom end of its + stroke the upper edge first overruns an exhaust port, and almost + immediately after uncovers an inlet port on the opposite side of the + cylinder and in communication with the crank chamber; the entering charge, + being under pressure, assists in expelling the exhaust gases from the + cylinder. On the next upstroke the charge is compressed into the + combustion space of the cylinder, a further charge simultaneously entering + the crank case to be compressed after the ignition for the working stroke. + To prevent the incoming charge escaping through the exhaust ports of the + cylinder a deflector is formed on the top of the piston, causing the fresh + gas to travel in an upward direction, thus avoiding as far as possible + escape of the mixture to the atmosphere. From experiments conducted in + 1910 by Professor Watson and Mr Fleming it was found that the proportion + of fresh gases which escaped unburnt through the exhaust ports diminished + with increase of speed; at 600 revolutions per minute about 36 per cent of + the fresh charge was lost; at 1,200 revolutions per minute this was + reduced to 20 per cent, and at 1,500 revolutions it was still farther + reduced to 6 per cent. + </p> + <p> + So much for the early designs. With regard to engines of this type + specially constructed for use with aircraft, three designs call for + special mention. Messrs A. Gobe and H. Diard, Parisian engineers, produced + an eight-cylindered two-stroke cycle engine of rotary design, the + cylinders being co-axial. Each pair of opposite pistons was secured + together by a rigid connecting rod, connected to a pin on a rotating + crankshaft which was mounted eccentrically to the axis of rotation of the + cylinders. The crankshaft carried a pinion gearing with an internally + toothed wheel on the transmission shaft which carried the air-screw. The + combustible mixture, emanating from a common supply pipe, was led through + conduits to the front ends of the cylinders, in which the charges were + compressed before being transferred to the working spaces through ports in + tubular extensions carried by the pistons. These extensions had also + exhaust ports, registering with ports in the cylinder which communicated + with the outer air, and the extensions slid over depending cylinder heads + attached to the crank case by long studs. The pump charge was compressed + in one end of each cylinder, and the pump spaces each delivered into their + corresponding adjacent combustion spaces. The charges entered the pump + spaces during the suction period through passages which communicated with + a central stationary supply passage at one end of the crank case, + communication being cut off when the inlet orifice to the passage passed + out of register with the port in the stationary member. The exhaust ports + at the outer end of the combustion space opened just before and closed a + little later than the air ports, and the incoming charge assisted in + expelling the exhaust gases in a manner similar to that of the earlier + types of two-stroke cycle engine; The accompanying rough diagram assists + in showing the working of this engine. + </p> + <p> + Exhibited in the Paris Aero Exhibition of 1912, the Laviator two-stroke + cycle engine, six-cylindered, could be operated either as a radial or as a + rotary engine, all its pistons acting on a single crank. Cylinder + dimensions of this engine were 3.94 inches bore by 5.12 inches stroke, and + a power output of 50 horse-power was obtained when working at a rate of + 1,200 revolutions per minute. Used as a radial engine, it developed 65 + horse-power at the same rate of revolution, and, as the total weight was + about 198 lbs., the weight of about 3 lbs. per horse-power was attained in + radial use. Stepped pistons were employed, the annular space between the + smaller or power piston and the walls of the larger cylinder being used as + a charging pump for the power cylinder situated 120 degrees in rear of it. + The charging cylinders were connected by short pipes to ports in the crank + case which communicated with the hollow crankshaft through which the fresh + gas was supplied, and once in each revolution each port in the case + registered with the port in the hollow shaft. The mixture which then + entered the charging cylinder was transferred to the corresponding working + cylinder when the piston of that cylinder had reached the end of its power + stroke, and immediately before this the exhaust ports diametrically + opposite the inlet ports were uncovered; scavenging was thus assisted in + the usual way. The very desirable feature of being entirely valveless was + accomplished with this engine, which is also noteworthy for exceedingly + compact design. + </p> + <p> + The Lamplough six-cylinder two-stroke cycle rotary, shown at the Aero + Exhibition at Olympia in 1911, had several innovations, including a + charging pump of rotary blower type. With the six cylinders, six power + impulses at regular intervals were given on each rotation; otherwise, the + cycle of operations was carried out much as in other two-stroke cycle + engines. The pump supplied the mixture under slight pressure to an inlet + port in each cylinder, which was opened at the same time as the exhaust + port, the period of opening being controlled by the piston. The rotary + blower sucked the mixture from the carburettor and delivered it to a + passage communicating with the inlet ports in the cylinder walls. A + mechanically-operated exhaust valve was placed in the centre of each + cylinder head, and towards the end of the working stroke this valve + opened, allowing part of the burnt gases to escape to the atmosphere; the + remainder was pushed out by the fresh mixture going in through the ports + at the bottom end of the cylinder. In practice, one or other of the + cylinders was always taking fresh mixture while working, therefore the + delivery from the pump was continuous and the mixture had not to be stored + under pressure. + </p> + <p> + The piston of this engine was long enough to keep the ports covered when + it was at the top of the stroke, and a bottom ring was provided to prevent + the mixture from entering the crank case. In addition to preventing + leakage, this ring no doubt prevented an excess of oil working up the + piston into the cylinder. As the cylinder fired with every revolution, the + valve gear was of the simplest construction, a fixed cam lifting each + valve as the cylinder came into position. The spring of the exhaust valve + was not placed round the stem in the usual way, but at the end of a short + lever, away from the heat of the exhaust gases. The cylinders were of cast + steel, the crank case of aluminium, and ball-bearings were fitted to the + crankshaft, crank pins, and the rotary blower pump. Ignition was by means + of a high-tension magneto of the two-spark pattern, and with a total + weight of 300 lbs. the maximum output was 102 brake horse-power, giving a + weight of just under 3 lbs. per horse-power. + </p> + <p> + One of the most successful of the two-stroke cycle engines was that + designed by Mr G. F. Mort and constructed by the New Engine Company. With + four cylinders of 3.69 inches bore by 4.5 inches stroke, and running at + 1,250 revolutions per minute, this engine developed 50 brake horse-power; + the total weight of the engine was 155 lbs., thus giving a weight of 3.1 + lbs. per horse-power. A scavenging pump of the rotary type was employed, + driven by means of gearing from the engine crankshaft, and in order to + reduce weight to a minimum the vanes were of aluminium. This engine was + tried on a biplane, and gave very satisfactory results. + </p> + <p> + American design yields two apparently successful two-stroke cycle aero + engines. A rotary called the Fredericson engine was said to give an output + of 70 brake horse-power with five cylinders 4.5 inches diameter by 4.75 + inches stroke, running at 1,000 revolutions per minute. Another, the + Roberts two-stroke cycle engine, yielded 100 brake horse-power from six + cylinders of the stepped piston design; two carburettors, each supplying + three cylinders, were fitted to this engine. Ignition was by means of the + usual high-tension magneto, gear-driven from the crankshaft, and the + engine, which was water-cooled, was of compact design. + </p> + <p> + It may thus be seen that the two-stroke cycle type got as far as actual + experiment in air work, and that with considerable success. So far, + however, the greater reliability of the four-stroke cycle has rendered it + practically the only aircraft engine, and the two-stroke has yet some way + to travel before it becomes a formidable competitor, in spite of its + admitted theoretical and questioned practical advantages. + </p> + <p> + <a name="link2H_4_0045" id="link2H_4_0045"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + VII. ENGINES OF THE WAR PERIOD + </h2> + <p> + The principal engines of British, French, and American design used in the + war period and since are briefly described under the four distinct types + of aero engine; such notable examples as the Rolls-Royce, Sunbeam, and + Napier engines have been given special mention, as they embodied—and + still embody—all that is best in aero engine practice. So far, + however, little has been said about the development of German aero engine + design, apart from the early Daimler and other pioneer makes. + </p> + <p> + At the outbreak of hostilities in 1914, thanks to subsidies to contractors + and prizes to aircraft pilots, the German aeroplane industry was in a + comparatively flourishing condition. There were about twenty-two + establishments making different types of heavier-than-air machines, + monoplane and biplane, engined for the most part with the four-cylinder + Argus or the six-cylinder Mercedes vertical type engines, each of these + being of 100 horse-power—it was not till war brought increasing + demands on aircraft that the limit of power began to rise. Contemporary + with the Argus and Mercedes were the Austro-Daimler, Benz, and N.A.G., in + vertical design, while as far as rotary types were concerned there were + two, the Oberursel and the Stahlhertz; of these the former was by far the + most promising, and it came to virtual monopoly of the rotary-engined + plane as soon as the war demand began. It was practically a copy of the + famous Gnome rotary, and thus deserves little description. + </p> + <p> + Germany, from the outbreak of war, practically, concentrated on the + development of the Mercedes engine; and it is noteworthy that, with one + exception, increase of power corresponding with the increased demand for + power was attained without increasing the number of cylinders. The various + models ranged between 75 and 260 horse-power, the latter being the most + recent production of this type. The exception to the rule was the + eight-cylinder 240 horse-power, which was replaced by the 260 horse-power + six-cylinder model, the latter being more reliable and but very slightly + heavier. Of the other engines, the 120 horsepower Argus and the 160 and + 225 horse-power Benz were the most used, the Oberursel being very largely + discarded after the Fokker monoplane had had its day, and the N.A.G. and + Austro-Daimler Daimler also falling to comparative disuse. It may be said + that the development of the Mercedes engine contributed very largely to + such success as was achieved in the war period by German aircraft, and, in + developing the engine, the builders were careful to make alterations in + such a way as to effect the least possible change in the design of + aeroplane to which they were to be fitted. Thus the engine base of the 175 + horse-power model coincided precisely with that of the 150 horse-power + model, and the 200 and 240 horse-power models retained the same base + dimensions. It was estimated, in 1918, that well over eighty per cent of + German aircraft was engined with the Mercedes type. + </p> + <p> + In design and construction, there was nothing abnormal about the Mercedes + engine, the keynote throughout being extreme reliability and such + simplification of design as would permit of mass production in different + factories. Even before the war, the long list of records set up by this + engine formed practical application of the wisdom of this policy; Bohn's + flight of 24 hours 10 minutes, accomplished on July 10th and 11th, 1914, + 9is an instance of this—the flight was accomplished on an Albatross + biplane with a 75 horsepower Mercedes engine. The radial type, instanced + in other countries by the Salmson and Anzani makes, was not developed in + Germany; two radial engines were made in that country before the war, but + the Germans seemed to lose faith in the type under war conditions, or it + may have been that insistence on standardisation ruled out all but the + proved examples of engine. + </p> + <p> + Details of one of the middle sizes of Mercedes motor, the 176 horse-power + type, apply very generally to the whole range; this size was in use up to + and beyond the conclusion of hostilities, and it may still be regarded as + characteristic of modern (1920) German practice. The engine is of the + fixed vertical type, has six cylinders in line, not off-set, and is + water-cooled. The cam shaft is carried in a special bronze casing, seated + on the immediate top of the cylinders, and a vertical shaft is interposed + between crankshaft and camshaft, the latter being driven by bevel gearing. + </p> + <p> + On this vertical connecting-shaft the water pump is located, serving to + steady the motion of the shaft. Extending immediately below the camshaft + is another vertical shaft, driven by bevel gears from the crank-shaft, and + terminating in a worm which drives the multiple piston oil pumps. + </p> + <p> + The cylinders are made from steel forgings, as are the valve chamber + elbows, which are machined all over and welded together. A jacket of light + steel is welded over the valve elbows and attached to a flange on the + cylinders, forming a water-cooling space with a section of about 7/16 of + an inch. The cylinder bore is 5.5 inches, and the stroke 6.29 inches. The + cylinders are attached to the crank case by means of dogs and long through + bolts, which have shoulders near their lower ends and are bolted to the + lower half of the crank chamber. A very light and rigid structure is thus + obtained, and the method of construction won the flattery of imitation by + makers of other nationality. + </p> + <p> + The cooling system for the cylinders is extremely efficient. After leaving + the water pump, the water enters the top of the front cylinders and passes + successively through each of the six cylinders of the row; short tubes, + welded to the tops of the cylinders, serve as connecting links in the + system. The Panhard car engines for years were fitted with a similar + cooling system, and the White and Poppe lorry engines were also similarly + fitted; the system gives excellent cooling effect where it is most needed, + round the valve chambers and the cylinder heads. + </p> + <p> + The pistons are built up from two pieces; a dropped forged steel piston + head, from which depend the piston pin bosses, is combined with a + cast-iron skirt, into which the steel head is screwed. Four rings are + fitted, three at the upper and one at the lower end of the piston skirt, + and two lubricating oil grooves are cut in the skirt, in addition to the + ring grooves. Two small rivets retain the steel head on the piston skirt + after it has been screwed into position, and it is also welded at two + points. The coefficient of friction between the cast-iron and steel is + considerably less than that which would exist between two steel parts, and + there is less tendency for the skirt to score the cylinder walls than + would be the case if all steel were used—so noticeable is this that + many makers, after giving steel pistons a trial, discarded them in favour + of cast-iron; the Gnome is an example of this, being originally fitted + with a steel piston carrying a brass ring, discarded in favour of a + cast-iron piston with a percentage of steel in the metal mixture. In the + Le Rhone engine the difficulty is overcome by a cast-iron liner to the + cylinders. + </p> + <p> + The piston pin of the Mercedes is of chrome nickel steel, and is retained + in the piston by means of a set screw and cotter pin. The connecting rods, + of I section, are very short and rigid, carrying floating bronze bushes + which fit the piston pins at the small end, and carrying an oil tube on + each for conveying oil from the crank pin to the piston pin. + </p> + <p> + The crankshaft is of chrome nickel steel, carried on seven bearings. Holes + are drilled through each of the crank pins and main bearings, for half the + diameter of the shaft, and these are plugged with pressed brass studs. + Small holes, drilled through the crank cheeks, serve to convey lubricant + from the main bearings to the crank pins. The propeller thrust is taken by + a simple ball thrust bearing at the propeller end of the crankshaft, this + thrust bearing being seated in a steel retainer which is clamped between + the two halves of the crank case. At the forward end of the crankshaft + there is mounted a master bevel gear on six splines; this bevel floats on + the splines against a ball thrust bearing, and, in turn, the thrust is + taken by the crank case cover. A stuffing box prevents the loss of + lubricant out of the front end of the crank chamber, and an oil thrower + ring serves a similar purpose at the propeller end of the crank chamber. + </p> + <p> + With a motor speed of 1,450 r.p.m., the vertical shaft at the forward end + of the motor turns at 2,175 r.p.m., this being the speed of the two + magnetos and the water pump. The lower vertical shaft bevel gear and the + magneto driving gear are made integral with the vertical driving shaft, + which is carried in plain bearings in an aluminium housing. This housing + is clamped to the upper half of the crank case by means of three studs. + The cam-shaft carries eighteen cams, these being the inlet and exhaust + cams, and a set of half compression cams which are formed with the exhaust + cams and are put into action when required by means of a lever at the + forward end of the cam-shaft. The cam-shaft is hollow, and serves as a + channel for the conveyance of lubricating oil to each of the camshaft + bearings. At the forward end of this shaft there is also mounted an air + pump for maintaining pressure on the fuel supply tank, and a bevel gear + tachometer drive. + </p> + <p> + Lubrication of the engine is carried out by a full pressure system. The + oil is pumped through a single manifold, with seven branches to the + crankshaft main bearings, and then in turn through the hollow crankshaft + to the connecting-rod big ends and thence through small tubes, already + noted, to the small end bearings. The oil pump has four pistons and two + double valves driven from a single eccentric shaft on which are mounted + four eccentrics. The pump is continuously submerged in oil; in order to + avoid great variations in pressure in the oil lines there is a piston + operated pressure regulator, cut in between the pump and the oil lines. + The two small pistons of the pump take fresh oil from a tank located in + the fuselage of the machine; one of these delivers oil to the cam shaft, + and one delivers to the crankshaft; this fresh oil mixes with the used + oil, returns to the base, and back to the main large oil pump cylinders. + By means of these small pump pistons a constant quantity of oil is kept in + the motor, and the oil is continually being freshened by means of the new + oil coming in. All the oil pipes are very securely fastened to the lower + half of the crank case, and some cooling of the oil is effected by air + passing through channels cast in the crank case on its way to the + carburettor. + </p> + <p> + A light steel manifold serves to connect the exhaust ports of the + cylinders to the main exhaust pipe, which is inclined about 25 degrees + from vertical and is arranged to give on to the atmosphere just over the + top of the upper wing of the aeroplane. + </p> + <p> + As regards carburation, an automatic air valve surrounds the throat of the + carburettor, maintaining normal composition of mixture. A small jet is + fitted for starting and running without load. The channels cast in the + crank chamber, already alluded to in connection with oil-cooling, serve to + warm the air before it reaches the carburettor, of which the body is + water-jacketed. + </p> + <p> + Ignition of the engine is by means of two Bosch ZH6 magnetos, driven at a + speed of 2,175 revolutions per minute when the engine is running at its + normal speed of 1,450 revolutions. The maximum advance of spark is 12 mm., + or 32 degrees before the top dead centre, and the firing order of the + cylinders is 1,5,3,6,2,4. + </p> + <p> + The radiator fitted to this engine, together with the water-jackets, has a + capacity of 25 litres of water, it is rectangular in shape, and is + normally tilted at an angle of 30 degrees from vertical. Its weight is 26 + kg., and it offers but slight head resistance in flight. + </p> + <p> + The radial type of engine, neglected altogether in Germany, was brought to + a very high state of perfection at the end of the War period by British + makers. Two makes, the Cosmos Engineering Company's 'Jupiter' and + 'Lucifer,' and the A.B.C. 'Wasp II' and 'Dragon Fly 1A' require special + mention for their light weight and reliability on trials. + </p> + <p> + The Cosmos 'Jupiter' was—for it is no longer being made—a 450 + horse-power nine-cylinder radial engine, air-cooled, with the cylinders + set in one single row; it was made both geared to reduce the propeller + revolutions relatively to the crankshaft revolutions, and ungeared; the + normal power of the geared type was 450 horse-power, and the total weight + of the engine, including carburettors, magnetos, etc., was only 757 lbs.; + the engine speed was 1,850 revolutions per minute, and the propeller + revolutions were reduced by the gearing to 1,200. Fitted to a 'Bristol + Badger' aeroplane, the total weight was 2,800 lbs., including pilot, + passenger, two machine-guns, and full military load; at 7,000 feet the + registered speed, with corrections for density, was 137 miles per hour; in + climbing, the first 2,000 feet was accomplished in 1 minute 4 seconds; + 4,000 feet was reached in 2 minutes 10 seconds; 6,000 feet was reached in + 3 minutes 33 seconds, and 7,000 feet in 4 minutes 15 seconds. It was + intended to modify the plane design and fit a new propeller, in order to + attain even better results, but, if trials were made with these + modifications, the results are not obtainable. + </p> + <p> + The Cosmos 'Lucifer' was a three-cylinder radial type engine of 100 + horse-power, inverted Y design, made on the simplest possible principles + with a view to quantity production and extreme reliability. The rated 100 + horse-power was attained at 1,600 revolutions per minute, and the cylinder + dimensions were 5.75 bore by 6.25 inches stroke. The cylinders were of + aluminium and steel mixture, with aluminium heads; overhead valves, + operated by push rods on the front side of the cylinders, were fitted, and + a simple reducing gear ran them at half engine speed. The crank case was a + circular aluminium casting, the engine being attached to the fuselage of + the aeroplane by a circular flange situated at the back of the case; + propeller shaft and crankshaft were integral. Dual ignition was provided, + the generator and distributors being driven off the back end of the engine + and the distributors being easily accessible. Lubrication was by means of + two pumps, one scavenging and one suction, oil being fed under pressure + from the crankshaft. A single carburettor fed all three cylinders, the + branch pipe from the carburettor to the circular ring being provided with + an exhaust heater. The total weight of the engine, 'all on,' was 280 lbs. + </p> + <p> + The A.B.C. 'Wasp II,' made by Walton Motors, Limited, is a seven-cylinder + radial, air-cooled engine, the cylinders having a bore of 4.75 inches and + stroke 6.25 inches. The normal brake horse-power at 1,650 revolutions is + 160, and the maximum 200 at a speed of 1,850 revolutions per minute. + Lubrication is by means of two rotary pumps, one feeding through the + hollow crankshaft to the crank pin, giving centrifugal feed to big end and + thence splash oiling, and one feeding to the nose of the engine, dropping + on to the cams and forming a permanent sump for the gears on the bottom of + the engine nose. Two carburettors are fitted, and two two-spark magnetos, + running at one and three-quarters engine speed. The total weight of this + engine is 350 lbs., or 1.75 lbs. per horse-power. Oil consumption at 1,850 + revolutions is.03 pints per horse-power per hour, and petrol consumption + is.56 pints per horsepower per hour. The engine thus shows as very + economical in consumption, as well as very light in weight. + </p> + <p> + The A.B.C. 'Dragon Fly 1A 'is a nine-cylinder radial engine having one + overhead inlet and two overhead exhaust valves per cylinder. The cylinder + dimensions are 5.5 inches bore by 6.5 inches stroke, and the normal rate + of speed, 1,650 revolutions per minute, gives 340 horse-power. The oiling + is by means of two pumps, the system being practically identical with that + of the 'Wasp II.' Oil consumption is.021 pints per brake horse-power per + hour, and petrol consumption.56 pints—the same as that of the 'Wasp + II.' The weight of the complete engine, including propeller boss, is 600 + lbs., or 1,765 lbs. per horse-power. + </p> + <p> + These A.B.C. radials have proved highly satisfactory on tests, and their + extreme simplicity of design and reliability commend them as engineering + products and at the same time demonstrate the value, for aero work, of the + air-cooled radial design—when this latter is accompanied by sound + workmanship. These and the Cosmos engines represent the minimum of weight + per horse-power yet attained, together with a practicable degree of + reliability, in radial and probably any aero engine design. + </p> + <p> + <a name="link2H_APPEa" id="link2H_APPEa"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + APPENDIX A + </h2> + <h3> + GENERAL MENSIER'S REPORT ON THE TRIALS OF CLEMENT ADER'S AVION. + </h3> +<pre xml:space="preserve"> + Paris, October 21, 1897. +</pre> + <p> + Report on the trials of M. Clement Ader's aviation apparatus. + </p> + <p> + M. Ader having notified the Minister of War by letter, July 21, 1897, that + the Apparatus of Aviation which he had agreed to build under the + conditions set forth in the convention of July 24th, 1894, was ready, and + therefore requesting that trials be undertaken before a Committee + appointed for this purpose as per the decision of August 4th, the + Committee was appointed as follows:— + </p> + <p> + Division General Mensier, Chairman; Division General Delambre, Inspector + General of the Permanent Works of Coast Defence, Member of the Technical + Committee of the Engineering Corps; Colonel Laussedat, Director of the + Conservatoire des Arts et Metiers; Sarrau, Member of the Institute, + Professor of Mechanical Engineering at the Polytechnic School; Leaute, + Member of the Institute, Professor of Mechanical Engineering at the + Polytechnique School. + </p> + <p> + Colonel Laussedat gave notice at once that his health and work as Director + of the Conservatoire des Arts et Metiers did not permit him to be a member + of the Committee; the Minister therefore accepted his resignation on + September 24th, and decided not to replace him. + </p> + <p> + Later on, however, on the request of the Chairman of the Committee, the + Minister appointed a new member General Grillon, commanding the Engineer + Corps of the Military Government of Paris. + </p> + <p> + To carry on the trials which were to take place at the camp of Satory, the + Minister ordered the Governor of the Military Forces of Paris to + requisition from the Engineer Corps, on the request of the Chairman of the + Committee, the men necessary to prepare the grounds at Satory. + </p> + <p> + After an inspection made on the 16th an aerodrome was chosen. M. Ader's + idea was to have it of circular shape with a width of 40 metres and an + average diameter of 450 metres. The preliminary work, laying out the + grounds, interior and exterior circumference, etc., was finished at the + end of August; the work of smoothing off the grounds began September 1st + with forty-five men and two rollers, and was finished on the day of the + first tests, October 12th. + </p> + <p> + The first meeting of the Committee was held August 18th in M. Ader's + workshop; the object being to demonstrate the machine to the Committee and + give all the information possible on the tests that were to be held. After + a careful examination and after having heard all the explanations by the + inventor which were deemed useful and necessary, the Committee decided + that the apparatus seemed to be built with a perfect understanding of the + purpose to be fulfilled as far as one could judge from a study of the + apparatus at rest; they therefore authorised M. Ader to take the machine + apart and carry it to the camp at Satory so as to proceed with the trials. + </p> + <p> + By letter of August 19th the Chairman made report to the Minister of the + findings of the Committee. + </p> + <p> + The work on the grounds having taken longer than was anticipated, the + Chairman took advantage of this delay to call the Committee together for a + second meeting, during which M. Ader was to run the two propulsive screws + situated at the forward end of the apparatus. + </p> + <p> + The meeting was held October 2nd. It gave the Committee an opportunity to + appreciate the motive power in all its details; firebox, boiler, engine, + under perfect control, absolute condensation, automatic fuel and feed of + the liquid to be vaporised, automatic lubrication and scavenging; + everything, in a word, seemed well designed and executed. + </p> + <p> + The weights in comparison with the power of the engine realised a + considerable advance over anything made to date, since the two engines + weighed together realised 42 kg., the firebox and boiler 60 kg., the + condenser 15 kg., or a total of 117 kg. for approximately 40 horse-power + or a little less than 3 kg. per horse-power. + </p> + <p> + One of the members summed up the general opinion by saying: 'Whatever may + be the result from an aviation point of view, a result which could not be + foreseen for the moment, it was nevertheless proven that from a mechanical + point of view M. Ader's apparatus was of the greatest interest and real + ingeniosity. He expressed a hope that in any case the machine would not be + lost to science.' + </p> + <p> + The second experiment in the workshop was made in the presence of the + Chairman, the purpose being to demonstrate that the wings, having a spread + of 17 metres, were sufficiently strong to support the weight of the + apparatus. With this object in view, 14 sliding supports were placed under + each one of these, representing imperfectly the manner in which the wings + would support the machine in the air; by gradually raising the supports + with the slides, the wheels on which the machine rested were lifted from + the ground. It was evident at that time that the members composing the + skeleton of the wings supported the apparatus, and it was quite evident + that when the wings were supported by the air on every point of their + surface, the stress would be better equalised than when resting on a few + supports, and therefore the resistance to breakage would be considerably + greater. + </p> + <p> + After this last test, the work on the ground being practically finished, + the machine was transported to Satory, assembled and again made ready for + trial. + </p> + <p> + At first M. Ader was to manoeuvre the machine on the ground at a moderate + speed, then increase this until it was possible to judge whether there was + a tendency for the machine to rise; and it was only after M. Ader had + acquired sufficient practice that a meeting of the Committee was to be + called to be present at the first part of the trials; namely, volutions of + the apparatus on the ground. + </p> + <p> + The first test took place on Tuesday, October 12th, in the presence of the + Chairman of the Committee. It had rained a good deal during the night and + the clay track would have offered considerable resistance to the rolling + of the machine; furthermore, a moderate wind was blowing from the + south-west, too strong during the early part of the afternoon to allow of + any trials. + </p> + <p> + Toward sunset, however, the wind having weakened, M. Ader decided to make + his first trial; the machine was taken out of its hangar, the wings were + mounted and steam raised. M. Ader in his seat had, on each side of him, + one man to the right and one to the left, whose duty was to rectify the + direction of the apparatus in the event that the action of the rear wheel + as a rudder would not be sufficient to hold the machine in a straight + course. + </p> + <p> + At 5.25 p.m. the machine was started, at first slowly and then at an + increased speed; after 250 or 300 metres, the two men who were being + dragged by the apparatus were exhausted and forced to fall flat on the + ground in order to allow the wings to pass over them, and the trip around + the track was completed, a total of 1,400 metres, without incident, at a + fair speed, which could be estimated to be from 300 to 400 metres per + minute. Notwithstanding M. Ader's inexperience, this being the first time + that he had run his apparatus, he followed approximately the chalk line + which marked the centre of the track and he stopped at the exact point + from which he started. + </p> + <p> + The marks of the wheels on the ground, which was rather soft, did not show + up very much, and it was clear that a part of the weight of the apparatus + had been supported by the wings, though the speed was only about one-third + of what the machine could do had M. Ader used all its motive power; he was + running at a pressure of from 3 to 4 atmospheres, when he could have used + 10 to 12. + </p> + <p> + This first trial, so fortunately accomplished, was of great importance; it + was the first time that a comparatively heavy vehicle (nearly 400 kg., + including the weight of the operator, fuel, and water) had been set in + motion by a tractive apparatus, using the air solely as a propelling + medium. The favourable report turned in by the Committee after the meeting + of October 2nd was found justified by the results demonstrated on the + grounds, and the first problem of aviation, namely, the creation of + efficient motive power, could be considered as solved, since the + propulsion of the apparatus in the air would be a great deal easier than + the traction on the ground, provided that the second part of the problem, + the sustaining of the machine in the air, would be realised. + </p> + <p> + The next day, Wednesday the 13th, no further trials were made on account + of the rain and wind. + </p> + <p> + On Thursday the 14th the Chairman requested that General Grillon, who had + just been appointed a member of the Committee, accompany him so as to have + a second witness. + </p> + <p> + The weather was fine, but a fairly strong, gusty wind was blowing from the + south. M. Ader explained to the two members of the Committee the danger of + these gusts, since at two points of the circumference the wind would + strike him sideways. The wind was blowing in the direction A B, the + apparatus starting from C, and running in the direction shown by the + arrow. The first dangerous spot would be at B. The apparatus had been kept + in readiness in the event of the wind dying down. Toward sunset the wind + seemed to die down, as it had done on the evening of the 12th. M. Ader + hesitated, which, unfortunately, further events only justified, but + decided to make a new trial. + </p> + <p> + At the start, which took place at 5.15 p.m., the apparatus, having the + wind in the rear, seemed to run at a fairly regular speed; it was, + nevertheless, easy to note from the marks of the wheels on the ground that + the rear part of the apparatus had been lifted and that the rear wheel, + being the rudder, had not been in constant contact with the ground. When + the machine came to the neighbourhood of B, the two members of the + Committee saw the machine swerve suddenly out of the track in a + semicircle, lean over to the right and finally stop. They immediately + proceeded to the point where the accident had taken place and endeavoured + to find an explanation for the same. The Chairman finally decided as + follows: + </p> + <p> + M. Ader was the victim of a gust of wind which he had feared as he + explained before starting out; feeling himself thrown out of his course, + he tried to use the rudder energetically, but at that time the rear wheel + was not in contact with the ground, and therefore did not perform its + function; the canvas rudder, which had as its purpose the manoeuvring of + the machine in the air, did not have sufficient action on the ground. It + would have been possible without any doubt to react by using the + propellers at unequal speed, but M. Ader, being still inexperienced, had + not thought of this. Furthermore, he was thrown out of his course so + quickly that he decided, in order to avoid a more serious accident, to + stop both engines. This sudden stop produced the half-circle already + described and the fall of the machine on its side. + </p> + <p> + The damage to the machine was serious; consisting at first sight of the + rupture of both propellers, the rear left wheel and the bending of the + left wing tip. It will only be possible to determine after the machine is + taken apart whether the engine, and more particularly the organs of + transmission, have been put out of line. + </p> + <p> + Whatever the damage may be, though comparatively easy to repair, it will + take a certain amount of time, and taking into consideration the time of + year it is evident that the tests will have to be adjourned for the + present. + </p> + <p> + As has been said in the above report, the tests, though prematurely + interrupted, have shown results of great importance, and though the final + results are hard to foresee, it would seem advisable to continue the + trials. By waiting for the return of spring there will be plenty of time + to finish the tests and it will not be necessary to rush matters, which + was a partial cause of the accident. The Chairman of the Committee + personally has but one hope, and that is that a decision be reached + accordingly. + </p> +<pre xml:space="preserve"> + Division General, + + Chairman of the Committee, + + Mensier. +</pre> + <p> + Boulogne-sur-Seine, October 21st, 1897. + </p> +<pre xml:space="preserve"> + Annex to the Report of October 21st. +</pre> + <p> + General Grillon, who was present at the trials of the 14th, and who saw + the report relative to what happened during that day, made the following + observations in writing, which are reproduced herewith in quotation marks. + The Chairman of the Committee does not agree with General Grillon and he + answers these observations paragraph by paragraph. + </p> + <p> + 1. 'If the rear wheel (there is only one of these) left but intermittent + tracks on the ground, does that prove that the machine has a tendency to + rise when running at a certain speed?' + </p> + <p> + Answer.—This does not prove anything in any way, and I was very + careful not to mention this in my report, this point being exactly what + was needed and that was not demonstrated during the two tests made on the + grounds. + </p> + <p> + 'Does not this unequal pressure of the two pair of wheels on the ground + show that the centre of gravity of the apparatus is placed too far forward + and that under the impulse of the propellers the machine has a tendency to + tilt forward, due to the resistance of the air?' + </p> + <p> + Answer.—The tendency of the apparatus to rise from the rear when it + was running with the wind seemed to be brought about by the effects of the + wind on the huge wings, having a spread of 17 metres, and I believe that + when the machine would have faced the wind the front wheels would have + been lifted. + </p> + <p> + During the trials of October 12th, when a complete circuit of the track + was accomplished without incidents, as I and Lieut. Binet witnessed, there + was practically no wind. I was therefore unable to verify whether during + this circuit the two front wheels or the rear wheel were in constant + contact with the ground, because when the trial was over it was dark (it + was 5.30) and the next day it was impossible to see anything because it + had rained during the night and during Wednesday morning. But what would + prove that the rear wheel was in contact with the ground at all times is + the fact that M. Ader, though inexperienced, did not swerve from the + circular track, which would prove that he steered pretty well with his + rear wheel—this he could not have done if he had been in the air. + </p> + <p> + In the tests of the 12th, the speed was at least as great as on the 14th. + </p> + <p> + 2. 'It would seem to me that if M. Ader thought that his rear wheels were + off the ground he should have used his canvas rudder in order to regain + his proper course; this was the best way of causing the machine to rotate, + since it would have given an angular motion to the front axle.' + </p> + <p> + Answer.—I state in my report that the canvas rudder whose object was + the manoeuvre of the apparatus in the air could have no effect on the + apparatus on the ground, and to convince oneself of this point it is only + necessary to consider the small surface of this canvas rudder compared + with the mass to be handled on the ground, a weight of approximately 400 + kg. According to my idea, and as I have stated in my report, M. Ader + should have steered by increasing the speed on one of his propellers and + slowing down the other. He admitted afterward that this remark was well + founded, but that he did not have time to think of it owing to the + suddenness of the accident. + </p> + <p> + 3. 'When the apparatus fell on its side it was under the sole influence of + the wind, since M. Ader had stopped the machine. Have we not a result here + which will always be the same when the machine comes to the ground, since + the engines will always have to be stopped or slowed down when coming to + the ground? Here seems to be a bad defect of the apparatus under trial.' + </p> + <p> + Answer.—I believe that the apparatus fell on its side after coming + to a stop, not on account of the wind, but because the semicircle + described was on rough ground and one of the wheels had collapsed. + </p> +<pre xml:space="preserve"> + Mensier. +</pre> + <p> + October 27th, 1897. + </p> + <p> + <a name="link2H_APPEb" id="link2H_APPEb"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + APPENDIX B + </h2> + <p> + Specification and Claims of Wright Patent, No. 821393. Filed March 23rd, + 1903. Issued May 22nd, 1906. Expires May 22nd, 1923. + </p> + <p> + To all whom it may concern. + </p> + <p> + Be it known that we, Orville Wright and Wilbur Wright, citizens of the + United States, residing in the city of Dayton, county of Montgomery, and + State of Ohio, have invented certain new and useful Improvements in Flying + Machines, of which the following is a specification. + </p> + <p> + Our invention relates to that class of flying-machines in which the weight + is sustained by the reactions resulting when one or more aeroplanes are + moved through the air edgewise at a small angle of incidence, either by + the application of mechanical power or by the utilisation of the force of + gravity. + </p> + <p> + The objects of our invention are to provide means for maintaining or + restoring the equilibrium or lateral balance of the apparatus, to provide + means for guiding the machine both vertically and horizontally, and to + provide a structure combining lightness, strength, convenience of + construction and certain other advantages which will hereinafter appear. + </p> + <p> + To these ends our invention consists in certain novel features, which we + will now proceed to describe and will then particularly point out in the + claims. In the accompanying drawings, Figure I 1 is a perspective view of + an apparatus embodying our invention in one form. Fig. 2 is a plan view of + the same, partly in horizontal section and partly broken away. Fig. 3 is a + side elevation, and Figs. 4 and 5 are detail views, of one form of + flexible joint for connecting the upright standards with the aeroplanes. + </p> + <p> + In flying machines of the character to which this invention relates the + apparatus is supported in the air by reason of the contact between the air + and the under surface of one or more aeroplanes, the contact surface being + presented at a small angle of incidence to the air. The relative movements + of the air and aeroplane may be derived from the motion of the air in the + form of wind blowing in the direction opposite to that in which the + apparatus is travelling or by a combined downward and forward movement of + the machine, as in starting from an elevated position or by combination of + these two things, and in either case the operation is that of a + soaring-machine, while power applied to the machine to propel it + positively forward will cause the air to support the machine in a similar + manner. In either case owing to the varying conditions to be met there are + numerous disturbing forces which tend to shift the machine from the + position which it should occupy to obtain the desired results. It is the + chief object of our invention to provide means for remedying this + difficulty, and we will now proceed to describe the construction by means + of which these results are accomplished. + </p> + <p> + In the accompanying drawing we have shown an apparatus embodying our + invention in one form. In this illustrative embodiment the machine is + shown as comprising two parallel superposed aeroplanes, 1 and 2, may be + embodied in a structure having a single aeroplane. Each aeroplane is of + considerably greater width from side to side than from front to rear. The + four corners of the upper aeroplane are indicated by the reference letters + a, b, c, and d, while the corresponding corners of the lower aeroplane 2 + are indicated by the reference letters e, f, g, and h. The marginal lines + ab and ef indicate the front edges of the aeroplanes, the lateral margins + of the upper aeroplane are indicated, respectively, by the lines ad and + bc, the lateral margins of the lower aeroplane are indicated, + respectively, by the lines eh and fg, while the rear margins of the upper + and lower aeroplanes are indicated, respectively, by the lines cd and gh. + </p> + <p> + Before proceeding to a description of the fundamental theory of operation + of the structure we will first describe the preferred mode of constructing + the aeroplanes and those portions of the structure which serve to connect + the two aeroplanes. + </p> + <p> + Each aeroplane is formed by stretching cloth or other suitable fabric over + a frame composed of two parallel transverse spars 3, extending from side + to side of the machine, their ends being connected by bows 4 extending + from front to rear of the machine. The front and rear spars 3 of each + aeroplane are connected by a series of parallel ribs 5, which preferably + extend somewhat beyond the rear spar, as shown. These spars, bows, and + ribs are preferably constructed of wood having the necessary strength, + combined with lightness and flexibility. Upon this framework the cloth + which forms the supporting surface of the aeroplane is secured, the frame + being enclosed in the cloth. The cloth for each aeroplane previous to its + attachment to its frame is cut on the bias and made up into a single piece + approximately the size and shape of the aeroplane, having the threads of + the fabric arranged diagonally to the transverse spars and longitudinal + ribs, as indicated at 6 in Fig. 2. Thus the diagonal threads of the cloth + form truss systems with the spars and ribs, the threads constituting the + diagonal members. A hem is formed at the rear edge of the cloth to receive + a wire 7, which is connected to the ends of the rear spar and supported by + the rearwardly-extending ends of the longitudinal ribs 5, thus forming a + rearwardly-extending flap or portion of the aeroplane. This construction + of the aeroplane gives a surface which has very great strength to + withstand lateral and longitudinal strains, at the same time being capable + of being bent or twisted in the manner hereinafter described. + </p> + <p> + When two aeroplanes are employed, as in the construction illustrated, they + are connected together by upright standards 8. These standards are + substantially rigid, being preferably constructed of wood and of equal + length, equally spaced along the front and rear edges of the aeroplane, to + which they are connected at their top and bottom ends by hinged joints or + universal joints of any suitable description. We have shown one form of + connection which may be used for this purpose in Figs. 4 and 5 of the + drawings. In this construction each end of the standard 8 has secured to + it an eye 9 which engages with a hook 10, secured to a bracket plate 11, + which latter plate is in turn fastened to the spar 3. Diagonal braces or + stay-wires 12 extend from each end of each standard to the opposite ends + of the adjacent standards, and as a convenient mode of attaching these + parts I have shown a hook 13 made integral with the hook 10 to receive the + end of one of the stay-wires, the other stay-wire being mounted on the + hook 10. The hook 13 is shown as bent down to retain the stay-wire in + connection to it, while the hook 10 is shown as provided with a pin 14 to + hold the staywire 12 and eye 9 in position thereon. It will be seen that + this construction forms a truss system which gives the whole machine great + transverse rigidity and strength, while at the same time the jointed + connections of the parts permit the aeroplanes to be bent or twisted in + the manner which we will now proceed to describe. + </p> + <p> + 15 indicates a rope or other flexible connection extending lengthwise of + the front of the machine above the lower aeroplane, passing under pulleys + or other suitable guides 16 at the front corners e and f of the lower + aeroplane, and extending thence upward and rearward to the upper rear + corners c and d, of the upper aeroplane, where they are attached, as + indicated at 17. To the central portion of the rope there is connected a + laterally-movable cradle 18, which forms a means for moving the rope + lengthwise in one direction or the other, the cradle being movable toward + either side of the machine. We have devised this cradle as a convenient + means for operating the rope 15, and the machine is intended to be + generally used with the operator lying face downward on the lower + aeroplane, with his head to the front, so that the operator's body rests + on the cradle, and the cradle can be moved laterally by the movements of + the operator's body. It will be understood, however, that the rope 15 may + be manipulated in any suitable manner. + </p> + <p> + 19 indicates a second rope extending transversely of the machine along the + rear edge of the body portion of the lower aeroplane, passing under + suitable pulleys or guides 20 at the rear corners g and h of the lower + aeroplane and extending thence diagonally upward to the front corners a + and b of the upper aeroplane, where its ends are secured in any suitable + manner, as indicated at 21. + </p> + <p> + Considering the structure so far as we have now described it, and assuming + that the cradle 18 be moved to the right in Figs. 1 and 2, as indicated by + the arrows applied to the cradle in Fig. 1 and by the dotted lines in Fig. + 2, it will be seen that that portion of the rope 15 passing under the + guide pulley at the corner e and secured to the corner d will be under + tension, while slack is paid out throughout the other side or half of the + rope 15. The part of the rope 15 under tension exercises a downward pull + upon the rear upper corner d of the structure and an upward pull upon the + front lower corner e, as indicated by the arrows. This causes the corner d + to move downward and the corner e to move upward. As the corner e moves + upward it carries the corner a upward with it, since the intermediate + standard 8 is substantially rigid and maintains an equal distance between + the corners a and e at all times. Similarly, the standard 8, connecting + the corners d and h, causes the corner h to move downward in unison with + the corner d. Since the corner a thus moves upward and the corner h moves + downward, that portion of the rope 19 connected to the corner a will be + pulled upward through the pulley 20 at the corner h, and the pull thus + exerted on the rope 19 will pull the corner b on the other wise of the + machine downward and at the same time pull the corner g at said other side + of the machine upward. This results in a downward movement of the corner b + and an upward movement of the corner c. Thus it results from a lateral + movement of the cradle 18 to the right in Fig. 1 that the lateral margins + ad and eh at one side of the machine are moved from their normal positions + in which they lie in the normal planes of their respective aeroplanes, + into angular relations with said normal planes, each lateral margin on + this side of the machine being raised above said normal plane at its + forward end and depressed below said normal plane at its rear end, said + lateral margins being thus inclined upward and forward. At the same time a + reverse inclination is imparted to the lateral margins bc end fg at the + other side of the machine, their inclination being downward and forward. + These positions are indicated in dotted lines in Fig. 1 of the drawings. A + movement of the cradle 18 in the opposite direction from its normal + position will reverse the angular inclination of the lateral margins of + the aeroplanes in an obvious manner. By reason of this construction it + will be seen that with the particular mode of construction now under + consideration it is possible to move the forward corner of the lateral + edges of the aeroplane on one side of the machine either above or below + the normal planes of the aeroplanes, a reverse movement of the forward + corners of the lateral margins on the other side of the machine occurring + simultaneously. During this operation each aeroplane is twisted or + distorted around a line extending centrally across the same from the + middle of one lateral margin to the middle of the other lateral margin, + the twist due to the moving of the lateral margins to different angles + extending across each aeroplane from side to side, so that each aeroplane + surface is given a helicoidal warp or twist. We prefer this construction + and mode of operation for the reason that it gives a gradually increasing + angle to the body of each aeroplane from the centre longitudinal line + thereof outward to the margin, thus giving a continuous surface on each + side of the machine, which has a gradually increasing or decreasing angle + of incidence from the centre of the machine to either side. We wish it to + be understood, however, that our invention is not limited to this + particular construction, since any construction whereby the angular + relations of the lateral margins of the aeroplanes may be varied in + opposite directions with respect to the normal planes of said aeroplanes + comes within the scope of our invention. Furthermore, it should be + understood that while the lateral margins of the aeroplanes move to + different angular positions with respect to or above and below the normal + planes of said aeroplanes, it does not necessarily follow that these + movements bring the opposite lateral edges to different angles + respectively above and below a horizontal plane since the normal planes of + the bodies of the aeroplanes are inclined to the horizontal when the + machine is in flight, said inclination being downward from front to rear, + and while the forward corners on one side of the machine may be depressed + below the normal planes of the bodies of the aeroplanes said depression is + not necessarily sufficient to carry them below the horizontal planes + passing through the rear corners on that side. Moreover, although we + prefer to so construct the apparatus that the movements of the lateral + margins on the opposite sides of the machine are equal in extent and + opposite m direction, yet our invention is not limited to a construction + producing this result, since it may be desirable under certain + circumstances to move the lateral margins on one side of the machine just + described without moving the lateral margins on the other side of the + machine to an equal extent in the opposite direction. Turning now to the + purpose of this provision for moving the lateral margins of the aeroplanes + in the manner described, it should be premised that owing to various + conditions of wind pressure and other causes the body of the machine is + apt to become unbalanced laterally, one side tending to sink and the other + side tending to rise, the machine turning around its central longitudinal + axis. The provision which we have just described enables the operator to + meet this difficulty and preserve the lateral balance of the machine. + Assuming that for some cause that side of the machine which lies to the + left of the observer in Figs. 1 and 2 has shown a tendency to drop + downward, a movement of the cradle 18 to the right of said figures, as + herein before assumed, will move the lateral margins of the aeroplanes in + the manner already described, so that the margins ad and eh will be + inclined downward and rearward, and the lateral margins bc and fg will be + inclined upward and rearward with respect to the normal planes of the + bodies of the aeroplanes. With the parts of the machine in this position + it will be seen that the lateral margins ad and eh present a larger angle + of incidence to the resisting air, while the lateral margins on the other + side of the machine present a smaller angle of incidence. Owing to this + fact, the side of the machine presenting the larger angle of incidence + will tend to lift or move upward, and this upward movement will restore + the lateral balance of the machine. When the other side of the machine + tends to drop, a movement of the cradle 18 in the reverse direction will + restore the machine to its normal lateral equilibrium. Of course, the same + effect will be produced in the same way in the case of a machine employing + only a single aeroplane. + </p> + <p> + In connection with the body of the machine as thus operated we employ a + vertical rudder or tail 22, so supported as to turn around a vertical + axis. This rudder is supported at the rear ends on supports or arms 23, + pivoted at their forward ends to the rear margins of the upper and lower + aeroplanes, respectively. These supports are preferably V-shaped, as + shown, so that their forward ends are comparatively widely separated, + their pivots being indicated at 24. Said supports are free to swing upward + at their free rear ends, as indicated in dotted lines in Fig. 3, their + downward movement being limited in any suitable manner. The vertical + pivots of the rudder 22 are indicated at 25, and one of these pivots has + mounted thereon a sheave or pulley 26, around which passes a tiller-rope + 27, the ends of which are extended out laterally and secured to the rope + 19 on opposite sides of the central point of said rope. By reason of this + construction the lateral shifting of the cradle 18 serves to turn the + rudder to one side or the other of the line of flight. It will be observed + in this connection that the construction is such that the rudder will + always be so turned as to present its resisting surface on that side of + the machine on which the lateral margins of the aeroplanes present the + least angle of resistance. The reason of this construction is that when + the lateral margins of the aeroplanes are so turned in the manner + hereinbefore described as to present different angles of incidence to the + atmosphere, that side presenting the largest angle of incidence, although + being lifted or moved upward in the manner already described, at the same + time meets with an increased resistance to its forward motion, while at + the same time the other side of the machine, presenting a smaller angle of + incidence, meets with less resistance to its forward motion and tends to + move forward more rapidly than the retarded side. This gives the machine a + tendency to turn around its vertical axis, and this tendency if not + properly met will not only change the direction of the front of the + machine, but will ultimately permit one side thereof to drop into a + position vertically below the other side with the aero planes in vertical + position, thus causing the machine to fall. The movement of the rudder, + hereinbefore described, prevents this action, since it exerts a retarding + influence on that side of the machine which tends to move forward too + rapidly and keeps the machine with its front properly presented to the + direction of flight and with its body properly balanced around its central + longitudinal axis. The pivoting of the supports 23 so as to permit them to + swing upward prevents injury to the rudder and its supports in case the + machine alights at such an angle as to cause the rudder to strike the + ground first, the parts yielding upward, as indicated in dotted lines in + Fig. 3, and thus preventing injury or breakage. We wish it to be + understood, however, that we do not limit ourselves to the particular + description of rudder set forth, the essential being that the rudder shall + be vertical and shall be so moved as to present its resisting surface on + that side of the machine which offers the least resistance to the + atmosphere, so as to counteract the tendency of the machine to turn around + a vertical axis when the two sides thereof offer different resistances to + the air. + </p> + <p> + From the central portion of the front of the machine struts 28 extend + horizontally forward from the lower aeroplane, and struts 29 extend + downward and forward from the central portion of the upper aeroplane, + their front ends being united to the struts 28, the forward extremities of + which are turned up, as indicated at 30. These struts 28 and 29 form + truss-skids projecting in front of the whole frame of the machine and + serving to prevent the machine from rolling over forward when it alights. + The struts 29 serve to brace the upper portion of the main frame and + resist its tendency to move forward after the lower aeroplane has been + stopped by its contact with the earth, thereby relieving the rope 19 from + undue strain, for it will be understood that when the machine comes into + contact with the earth, further forward movement of the lower portion + thereof being suddenly arrested, the inertia of the upper portion would + tend to cause it to continue to move forward if not prevented by the + struts 29, and this forward movement of the upper portion would bring a + very violent strain upon the rope 19, since it is fastened to the upper + portion at both of its ends, while its lower portion is connected by the + guides 20 to the lower portion. The struts 28 and 29 also serve to support + the front or horizontal rudder, the construction of which we will now + proceed to describe. + </p> + <p> + The front rudder 31 is a horizontal rudder having a flexible body, the + same consisting of three stiff crosspieces or sticks 32, 33, and 34, and + the flexible ribs 35, connecting said cross-pieces and extending from + front to rear. The frame thus provided is covered by a suitable fabric + stretched over the same to form the body of the rudder. The rudder is + supported from the struts 29 by means of the intermediate cross-piece 32, + which is located near the centre of pressure slightly in front of a line + equidistant between the front and rear edges of the rudder, the + cross-piece 32 forming the pivotal axis of the rudder, so as to constitute + a balanced rudder. To the front edge of the rudder there are connected + springs 36 which springs are connected to the upturned ends 30 of the + struts 28, the construction being such that said springs tend to resist + any movement either upward or downward of the front edge of the horizontal + rudder. The rear edge of the rudder lies immediately in front of the + operator and may be operated by him in any suitable manner. We have shown + a mechanism for this purpose comprising a roller or shaft 37, which may be + grasped by the operator so as to turn the same in either direction. Bands + 38 extend from the roller 37 forward to and around a similar roller or + shaft 39, both rollers or shafts being supported in suitable bearings on + the struts 28. The forward roller or shaft has rearwardly-extending arms + 40, which are connected by links 41 with the rear edge of the rudder 31. + The normal position of the rudder 31 is neutral or substantially parallel + with the aeroplanes 1 and 2; but its rear edge may be moved upward or + downward, so as to be above or below the normal plane of said rudder + through the mechanism provided for that purpose. It will be seen that the + springs 36 will resist any tendency of the forward edge of the rudder to + move in either direction, so that when force is applied to the rear edge + of said rudder the longitudinal ribs 35 bend, and the rudder thus presents + a concave surface to the action of the wind either above or below its + normal plane, said surface presenting a small angle of incidence at its + forward portion and said angle of incidence rapidly increasing toward the + rear. This greatly increases the efficiency of the rudder as compared with + a plane surface of equal area. By regulating the pressure on the upper and + lower sides of the rudder through changes of angle and curvature in the + manner described a turning movement of the main structure around its + transverse axis may be effected, and the course of the machine may thus be + directed upward or downward at the will of the operator and the + longitudinal balance thereof maintained. + </p> + <p> + Contrary to the usual custom, we place the horizontal rudder in front of + the aeroplanes at a negative angle and employ no horizontal tail at all. + By this arrangement we obtain a forward surface which is almost entirely + free from pressure under ordinary conditions of flight, but which even if + not moved at all from its original position becomes an efficient + lifting-surface whenever the speed of the machine is accidentally reduced + very much below the normal, and thus largely counteracts that backward + travel of the centre of pressure on the aeroplanes which has frequently + been productive of serious injuries by causing the machine to turn + downward and forward and strike the ground head-on. We are aware that a + forward horizontal rudder of different construction has been used in + combination with a supporting surface and a rear horizontal-rudder; but + this combination was not intended to effect and does not effect the object + which we obtain by the arrangement hereinbefore described. + </p> + <p> + We have used the term 'aeroplane' in this specification and the appended + claims to indicate the supporting surface or supporting surfaces by means + of which the machine is sustained in the air, and by this term we wish to + be understood as including any suitable supporting surface which normally + is substantially flat, although. Of course, when constructed of cloth or + other flexible fabric, as we prefer to construct them, these surfaces may + receive more or less curvature from the resistance of the air, as + indicated in Fig. 3. + </p> + <p> + We do not wish to be understood as limiting ourselves strictly to the + precise details of construction hereinbefore described and shown in the + accompanying drawings, as it is obvious that these details may be modified + without departing from the principles of our invention. For instance, + while we prefer the construction illustrated in which each aeroplane is + given a twist along its entire length in order to set its opposite lateral + margins at different angles, we have already pointed out that our + invention is not limited to this form of construction, since it is only + necessary to move the lateral marginal portions, and where these portions + alone are moved only those upright standards which support the movable + portion require flexible connections at their ends. + </p> + <p> + Having thus fully described our invention, what we claim as new, and + desire to secure by Letters Patent, is:— + </p> + <p> + 1. In a flying machine, a normally flat aeroplane having lateral marginal + portions capable of movement to different positions above or below the + normal plane of the body of the aeroplane, such movement being about an + axis transverse to the line of flight, whereby said lateral marginal + portions may be moved to different angles relatively to the normal plane + of the body of the aeroplane, so as to present to the atmosphere different + angles of incidence, and means for so moving said lateral marginal + portions, substantially as described. + </p> + <p> + 2. In a flying machine, the combination, with two normally parallel + aeroplanes, superposed the one above the other, of upright standards + connecting said planes at their margins, the connections between the + standards and aeroplanes at the lateral portions of the aeroplanes being + by means of flexible joints, each of said aeroplanes having lateral + marginal portions capable of movement to different positions above or + below the normal plane of the body of the aeroplane, such movement being + about an axis transverse to the line of flight, whereby said lateral + marginal portions may be moved to different angles relatively to the + normal plane of the body of the aeroplane, so as to present to the + atmosphere different angles of incidence, the standards maintaining a + fixed distance between the portions of the aeroplanes which they connect, + and means for imparting such movement to the lateral marginal portions of + the aeroplanes, substantially as described. + </p> + <p> + 3. In a flying machine, a normally flat aeroplane having lateral marginal + portions capable of movement to different positions above or below the + normal plane of the body of the aeroplane, such movement being about an + axis transverse to the line of flight, whereby said lateral marginal + portions may be moved to different angles relatively to the normal plane + of the body of the aeroplane, and also to different angles relatively to + each other, so as to present to the atmosphere different angles of + incidence, and means for simultaneously imparting such movement to said + lateral marginal portions, substantially as described. + </p> + <p> + 4. In a flying machine, the combination, with parallel superposed + aeroplanes, each having lateral marginal portions capable of movement to + different positions above or below the normal plane of the body of the + aeroplane, such movement being about an axis transverse to the line of + flight, whereby said lateral marginal portions may be moved to different + angles relatively to the normal plane of the body of the aeroplane, and to + different angles relatively to each other, so as to present to the + atmosphere different angles of incidence, of uprights connecting said + aeroplanes at their edges, the uprights connecting the lateral portions of + the aeroplanes being connected with said aeroplanes by flexible joints, + and means for simultaneously imparting such movement to said lateral + marginal portions, the standards maintaining a fixed distance between the + parts which they connect, whereby the lateral portions on the same side of + the machine are moved to the same angle, substantially as described. + </p> + <p> + 5. In a flying machine, an aeroplane having substantially the form of a + normally flat rectangle elongated transversely to the line of flight, in + combination which means for imparting to the lateral margins of said + aeroplane a movement about an axis lying in the body of the aeroplane + perpendicular to said lateral margins, and thereby moving said lateral + margins into different angular relations to the normal plane of the body + of the aeroplane, substantially as described. + </p> + <p> + 6. In a flying machine, the combination, with two superposed and normally + parallel aeroplanes, each having substantially the form of a normally flat + rectangle elongated transversely to the line of flight, of upright + standards connecting the edges of said aeroplanes to maintain their + equidistance, those standards at the lateral portions of said aeroplanes + being connected therewith by flexible joints, and means for simultaneously + imparting to both lateral margins of both aeroplanes a movement about axes + which are perpendicular to said margins and in the planes of the bodies of + the respective aeroplanes, and thereby moving the lateral margins on the + opposite sides of the machine into different angular relations to the + normal planes of the respective aeroplanes, the margins on the same side + of the machine moving to the same angle, and the margins on one side of + the machine moving to an angle different from the angle to which the + margins on the other side of the machine move, substantially as described. + </p> + <p> + 7. In a flying machine, the combination, with an aeroplane, and means for + simultaneously moving the lateral portions thereof into different angular + relations to the normal plane of the body of the aeroplane and to each + other, so as to present to the atmosphere different angles of incidence, + of a vertical rudder, and means whereby said rudder is caused to present + to the wind that side thereof nearest the side of the aeroplane having the + smaller angle of incidence and offering the least resistance to the + atmosphere, substantially as described. + </p> + <p> + 8. In a flying machine, the combination, with two superposed and normally + parallel aeroplanes, upright standards connecting the edges of said + aeroplanes to maintain their equidistance, those standards at the lateral + portions of said aeroplanes being connected therewith by flexible joints, + and means for simultaneously moving both lateral portions of both + aeroplanes into different angular relations to the normal planes of the + bodies of the respective aeroplanes, the lateral portions on one side of + the machine being moved to an angle different from that to which the + lateral portions on the other side of the machine are moved, so as to + present different angles of incidence at the two sides of the machine, of + a vertical rudder, and means whereby said rudder is caused to present to + the wind that side thereof nearest the side of the aeroplanes having the + smaller angle of incidence and offering the least resistance to the + atmosphere, substantially as described. + </p> + <p> + 9. In a flying machine, an aeroplane normally flat and elongated + transversely to the line of flight, in combination with means for + imparting to said aeroplane a helicoidal warp around an axis transverse to + the line of flight and extending centrally along the body aeroplane in the + direction of the elongation aeroplane, substantially as described. + </p> + <p> + 10. In a flying machine, two aeroplanes, each normally flat and elongated + transversely to the line of flight, and upright standards connecting the + edges of said aeroplanes to maintain their equidistance, the connections + between said standards and aeroplanes being by means of flexible joints, + in combination with means for simultaneously imparting to each of said + aeroplanes a helicoidal warp around an axis transverse to the line of + flight and extending centrally along the body of the aeroplane in the + direction of the aeroplane, substantially as described. + </p> + <p> + 11. In a flying machine, two aeroplanes, each normally flat and elongated + transversely to the line of flight, and upright standards connecting the + edges of said aeroplanes to maintain their equidistance, the connections + between such standards and aeroplanes being by means of flexible joints, + in combination with means for simultaneously imparting to each of said + aeroplanes a helicoidal warp around an axis transverse to the line of + flight and extending centrally along the body of the aeroplane in the + direction of the elongation of the aeroplane, a vertical rudder, and means + whereby said rudder is caused to present to the wind that side thereof + nearest the side of the aeroplanes having the smaller angle of incidence + and offering the least resistance to the atmosphere, substantially as + described. + </p> + <p> + 12. In a flying machine, the combination, with an aeroplane, of a normally + flat and substantially horizontal flexible rudder, and means for curving + said rudder rearwardly and upwardly or rearwardly and downwardly with + respect to its normal plane, substantially as described. + </p> + <p> + 13. In a flying machine, the combination, with an aeroplane, of a normally + flat and substantially horizontal flexible rudder pivotally mounted on an + axis transverse to the line of flight near its centre, springs resisting + vertical movement of the front edge of said rudder, and means for moving + the rear edge of said rudder, above or below the normal plane thereof, + substantially as described. + </p> + <p> + 14. A flying machine comprising superposed connected aeroplanes means for + moving the opposite lateral portions of said aeroplanes to different + angles to the normal planes thereof, a vertical rudder, means for moving + said vertical rudder toward that side of the machine presenting the + smaller angle of incidence and the least resistance to the atmosphere, and + a horizontal rudder provided with means for presenting its upper or under + surface to the resistance of the atmosphere, substantially as described. + </p> + <p> + 15. A flying machine comprising superposed connected aeroplanes, means for + moving the opposite lateral portions of said aeroplanes to different + angles to the normal planes thereof, a vertical rudder, means for moving + said vertical rudder toward that side of the machine presenting the + smaller angle of incidence and the least resistance to the atmosphere, and + a horizontal rudder provided with means for presenting its upper or under + surface to the resistance of the atmosphere, said vertical rudder being + located at the rear of the machine and said horizontal rudder at the front + of the machine, substantially as described. + </p> + <p> + 16. In a flying machine, the combination, with two superposed and + connected aeroplanes, of an arm extending rearward from each aeroplane, + said arms being parallel and free to swing upward at their rear ends, and + a vertical rudder pivotally mounted in the rear ends of said arms, + substantially as described. + </p> + <p> + 17. A flying machine comprising two superposed aeroplanes, normally flat + but flexible, upright standards connecting the margins of said aeroplanes, + said standards being connected to said aeroplanes by universal joints, + diagonal stay-wires connecting the opposite ends of the adjacent + standards, a rope extending along the front edge of the lower aeroplane, + passing through guides at the front corners thereof, and having its ends + secured to the rear corners of the upper aeroplane, and a rope extending + along the rear edge of the lower aeroplane, passing through guides at the + rear corners thereof, and having its ends secured to the front corners of + the upper aeroplane, substantially as described. + </p> + <p> + 18. A flying machine comprising two superposed aeroplanes, normally flat + but flexible, upright standards connecting the margins of said aeroplanes, + said standards being connected to said aeroplanes by universal joints, + diagonal stay-wires connecting the opposite ends of the adjacent + standards, a rope extending along the front edge of the lower aeroplane, + passing through guides at the front corners thereof, and having its ends + secured to the rear corners of the upper aeroplane, and a rope extending + along the rear edge of the lower aeroplane, passing through guides at the + rear corners thereof, and having its ends secured to the front corners of + the upper aeroplane, in combination with a vertical rudder, and a + tiller-rope connecting said rudder with the rope extending along the rear + edge of the lower aeroplane, substantially as described. + </p> +<pre xml:space="preserve"> + ORVILLE WRIGHT. + + WILBUR WRIGHT. +</pre> + <p> + Witnesses: + </p> + <p> + Chas. E. Taylor. + </p> + <p> + E. Earle Forrer. + </p> + <p> + <a name="link2H_APPEc" id="link2H_APPEc"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + APPENDIX C + </h2> + <p> + Proclamation published by the French Government on balloon ascents, 1783. + </p> +<pre xml:space="preserve"> + NOTICE TO THE PUBLIC! PARIS, 27TH AUGUST, 1783. +</pre> + <p> + On the Ascent of balloons or globes in the air. The one in question has + been raised in Paris this day, 27th August, 1783, at 5 p.m., in the Champ + de Mars. + </p> + <p> + A Discovery has been made, which the Government deems it right to make + known, so that alarm be not occasioned to the people. + </p> + <p> + On calculating the different weights of hot air, hydrogen gas, and common + air, it has been found that a balloon filled with either of the two former + will rise toward heaven till it is in equilibrium with the surrounding + air, which may not happen until it has attained a great height. + </p> + <p> + The first experiment was made at Annonay, in Vivarais, MM. Montgolfier, + the inventors; a globe formed of canvas and paper, 105 feet in + circumference, filled with heated air, reached an uncalculated height. The + same experiment has just been renewed in Paris before a great crowd. A + globe of taffetas or light canvas covered by elastic gum and filled with + inflammable air, has risen from the Champ de Mars, and been lost to view + in the clouds, being borne in a north-westerly direction. One cannot + foresee where it will descend. + </p> + <p> + It is proposed to repeat these experiments on a larger scale. Any one who + shall see in the sky such a globe, which resembles 'la lune obscurcie,' + should be aware that, far from being an alarming phenomenon, it is only a + machine that cannot possibly cause any harm, and which will some day prove + serviceable to the wants of society. + </p> + <p> + (Signed) DE SAUVIGNY. + </p> + <p> + LENOIR. <br /><br /> + </p> +<pre xml:space="preserve"> + + + + + +End of Project Gutenberg's A History of Aeronautics, by E. 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Charles Vivian + +Posting Date: July 26, 2008 [EBook #874] +Release Date: April, 1997 + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK A HISTORY OF AERONAUTICS *** + + + + +Produced by Dianne Bean + + + + + +A HISTORY OF AERONAUTICS + +by E. Charles Vivian + + + + +FOREWORD + +Although successful heavier-than-air flight is less than two decades +old, and successful dirigible propulsion antedates it by a very short +period, the mass of experiment and accomplishment renders any one-volume +history of the subject a matter of selection. In addition to the +restrictions imposed by space limits, the material for compilation is +fragmentary, and, in many cases, scattered through periodical and +other publications. Hitherto, there has been no attempt at furnishing a +detailed account of how the aeroplane and the dirigible of to-day came +to being, but each author who has treated the subject has devoted his +attention to some special phase or section. The principal exception to +this rule--Hildebrandt--wrote in 1906, and a good many of his statements +are inaccurate, especially with regard to heavier-than-air experiment. + +Such statements as are made in this work are, where possible, given +with acknowledgment to the authorities on which they rest. Further +acknowledgment is due to Lieut.-Col. Lockwood Marsh, not only for the +section on aeroplane development which he has contributed to the work, +but also for his kindly assistance and advice in connection with the +section on aerostation. The author's thanks are also due to the +Royal Aeronautical Society for free access to its valuable library of +aeronautical literature, and to Mr A. Vincent Clarke for permission to +make use of his notes on the development of the aero engine. + +In this work is no claim to originality--it has been a matter mainly of +compilation, and some stories, notably those of the Wright Brothers and +of Santos Dumont, are better told in the words of the men themselves +than any third party could tell them. The author claims, however, that +this is the first attempt at recording the facts of development and +stating, as fully as is possible in the compass of a single volume, how +flight and aerostation have evolved. The time for a critical history of +the subject is not yet. + +In the matter of illustrations, it has been found very difficult to +secure suitable material. Even the official series of photographs of +aeroplanes in the war period is curiously incomplete' and the methods +of censorship during that period prevented any complete series being +privately collected. Omissions in this respect will probably be remedied +in future editions of the work, as fresh material is constantly being +located. + +E.C.V. October, 1920. + + + + +CONTENTS + + Part I--THE EVOLUTION OF THE AEROPLANE + I. THE PERIOD OF LEGEND + II. EARLY EXPERIMENTS + III. SIR GEORGE CAYLEY--THOMAS WALKER + IV. THE MIDDLE NINETEENTH CENTURY + V. WENHAM, LE BRIS, AND SOME OTHERS + VI. THE AGE OF THE GIANTS + VII. LILIENTHAL AND PILCHER + VIII. AMERICAN GLIDING EXPERIMENTS + IX. NOT PROVEN + X. SAMUEL PIERPOINT LANGLEY + XI. THE WRIGHT BROTHERS + XII. THE FIRST YEARS OF CONQUEST + XIII. FIRST FLIERS IN ENGLAND + XIV. RHEIMS, AND AFTER + XV. THE CHANNEL CROSSING + XVI. LONDON TO MANCHESTER + XVII. A SUMMARY--TO 1911 + XVIII. A SUMMARY--TO 1914 + XIX. THE WAR PERIOD--I + XX. THE WAR PERIOD--II + XXI. RECONSTRUCTION + XXII. 1919-1920 + + Part II--1903-1920: PROGRESS IN DESIGN + I. THE BEGINNINGS + II. MULTIPLICITY OF IDEAS + III. PROGRESS ON STANDARDISED LINES + IV. THE WAR PERIOD + + Part III--AEROSTATICS + I. BEGINNINGS + II. THE FIRST DIRIGIBLES + III. SANTOS-DUMONT + IV. THE MILITARY DIRIGIBLE + V. BRITISH AIRSHIP DESIGN + VI. THE AIRSHIP COMMERCIALLY + VII. KITE BALLOONS + + PART IV--ENGINE DEVELOPMENT + I. THE VERTICAL TYPE + II. THE VEE TYPE + III. THE RADIAL TYPE + IV. THE ROTARY TYPE + V. THE HORIZONTALLY-OPPOSED ENGINE + VI. THE TWO-STROKE CYCLE ENGINE + VII. ENGINES OF THE WAR PERIOD + + APPENDICES + + + + +PART I. THE EVOLUTION OF THE AEROPLANE + + + + +I. THE PERIOD OF LEGEND + +The blending of fact and fancy which men call legend reached its fullest +and richest expression in the golden age of Greece, and thus it is to +Greek mythology that one must turn for the best form of any legend which +foreshadows history. Yet the prevalence of legends regarding flight, +existing in the records of practically every race, shows that this form +of transit was a dream of many peoples--man always wanted to fly, and +imagined means of flight. + +In this age of steel, a very great part of the inventive genius of man +has gone into devices intended to facilitate transport, both of men and +goods, and the growth of civilisation is in reality the facilitation of +transit, improvement of the means of communication. He was a genius who +first hoisted a sail on a boat and saved the labour of rowing; equally, +he who first harnessed ox or dog or horse to a wheeled vehicle was a +genius--and these looked up, as men have looked up from the earliest +days of all, seeing that the birds had solved the problem of transit far +more completely than themselves. So it must have appeared, and there +is no age in history in which some dreamers have not dreamed of the +conquest of the air; if the caveman had left records, these would +without doubt have showed that he, too, dreamed this dream. His main +aim, probably, was self-preservation; when the dinosaur looked round the +corner, the prehistoric bird got out of the way in his usual manner, +and prehistoric man, such of him as succeeded in getting out of the way +after his fashion--naturally envied the bird, and concluded that as lord +of creation in a doubtful sort of way he ought to have equal +facilities. He may have tried, like Simon the Magician, and other early +experimenters, to improvise those facilities; assuming that he did, +there is the groundwork of much of the older legend with regard to men +who flew, since, when history began, legends would be fashioned out +of attempts and even the desire to fly, these being compounded of some +small ingredient of truth and much exaggeration and addition. + +In a study of the first beginnings of the art, it is worth while to +mention even the earliest of the legends and traditions, for they show +the trend of men's minds and the constancy of this dream that has become +reality in the twentieth century. In one of the oldest records of the +world, the Indian classic Mahabarata, it is stated that 'Krishna's +enemies sought the aid of the demons, who built an aerial chariot with +sides of iron and clad with wings. The chariot was driven through the +sky till it stood over Dwarakha, where Krishna's followers dwelt, +and from there it hurled down upon the city missiles that destroyed +everything on which they fell.' Here is pure fable, not legend, but +still a curious forecast of twentieth century bombs from a rigid +dirigible. It is to be noted in this case, as in many, that the power to +fly was an attribute of evil, not of good--it was the demons who built +the chariot, even as at Friedrichshavn. Mediaeval legend in nearly +every case, attributes flight to the aid of evil powers, and incites +well-disposed people to stick to the solid earth--though, curiously +enough, the pioneers of medieval times were very largely of priestly +type, as witness the monk of Malmesbury. + +The legends of the dawn of history, however, distribute the power of +flight with less of prejudice. Egyptian sculpture gives the figure +of winged men; the British Museum has made the winged Assyrian bulls +familiar to many, and both the cuneiform records of Assyria and the +hieroglyphs of Egypt record flights that in reality were never made. +The desire fathered the story then, and until Clement Ader either hopped +with his Avion, as is persisted by his critics, or flew, as is claimed +by his friends. + +While the origin of many legends is questionable, that of others is +easy enough to trace, though not to prove. Among the credulous the +significance of the name of a people of Asia Minor, the Capnobates, +'those who travel by smoke,' gave rise to the assertion that Montgolfier +was not first in the field--or rather in the air--since surely this +people must have been responsible for the first hot-air balloons. Far +less questionable is the legend of Icarus, for here it is possible +to trace a foundation of fact in the story. Such a tribe as Daedalus +governed could have had hardly any knowledge of the rudiments of +science, and even their ruler, seeing how easy it is for birds to +sustain themselves in the air, might be excused for believing that he, +if he fashioned wings for himself, could use them. In that belief, let +it be assumed, Daedalus made his wings; the boy, Icarus, learning that +his father had determined on an attempt at flight secured the wings and +fastened them to his own shoulders. A cliff seemed the likeliest place +for a 'take-off,' and Icarus leaped from the cliff edge only to find +that the possession of wings was not enough to assure flight to a human +being. The sea that to this day bears his name witnesses that he made +the attempt and perished by it. + +In this is assumed the bald story, from which might grow the legend of a +wise king who ruled a peaceful people--'judged, sitting in the sun,' as +Browning has it, and fashioned for himself wings with which he flew over +the sea and where he would, until the prince, Icarus, desired to emulate +him. Icarus, fastening the wings to his shoulders with wax, was so +imprudent as to fly too near the sun, when the wax melted and he fell, +to lie mourned of water-nymphs on the shores of waters thenceforth +Icarian. Between what we have assumed to be the base of fact, and the +legend which has been invested with such poetic grace in Greek story, +there is no more than a century or so of re-telling might give to any +event among a people so simple and yet so given to imagery. + +We may set aside as pure fable the stories of the winged horse of +Perseus, and the flights of Hermes as messenger of the gods. With them +may be placed the story of Empedocles, who failed to take Etna seriously +enough, and found himself caught by an eruption while within the crater, +so that, flying to safety in some hurry, he left behind but one sandal +to attest that he had sought refuge in space--in all probability, if +he escaped at all, he flew, but not in the sense that the aeronaut +understands it. But, bearing in mind the many men who tried to fly +in historic times, the legend of Icarus and Daedalus, in spite of the +impossible form in which it is presented, may rank with the story of the +Saracen of Constantinople, or with that of Simon the Magician. A simple +folk would naturally idealise the man and magnify his exploit, as they +magnified the deeds of some strong man to make the legends of Hercules, +and there, full-grown from a mere legend, is the first record of a +pioneer of flying. Such a theory is not nearly so fantastic as that +which makes the Capnobates, on the strength of their name, the inventors +of hot-air balloons. However it may be, both in story and in picture, +Icarus and his less conspicuous father have inspired the Caucasian mind, +and the world is the richer for them. + +Of the unsupported myths--unsupported, that is, by even a shadow of +probability--there is no end. Although Latin legend approaches nearer +to fact than the Greek in some cases, in others it shows a disregard +for possibilities which renders it of far less account. Thus Diodorus of +Sicily relates that one Abaris travelled round the world on an arrow of +gold, and Cassiodorus and Glycas and their like told of mechanical birds +that flew and sang and even laid eggs. More credible is the story +of Aulus Gellius, who in his Attic Nights tells how Archytas, four +centuries prior to the opening of the Christian era, made a wooden +pigeon that actually flew by means of a mechanism of balancing weights +and the breath of a mysterious spirit hidden within it. There may yet +arise one credulous enough to state that the mysterious spirit was +precursor of the internal combustion engine, but, however that may be, +the pigeon of Archytas almost certainly existed, and perhaps it actually +glided or flew for short distances--or else Aulus Gellius was an utter +liar, like Cassiodorus and his fellows. In far later times a certain +John Muller, better known as Regiomontanus, is stated to have made an +artificial eagle which accompanied Charles V. on his entry to and exit +from Nuremberg, flying above the royal procession. But, since Muller +died in 1436 and Charles was born in 1500, Muller may be ruled out from +among the pioneers of mechanical flight, and it may be concluded that +the historian of this event got slightly mixed in his dates. + +Thus far, we have but indicated how one may draw from the richest +stores from which the Aryan mind draws inspiration, the Greek and Latin +mythologies and poetic adaptations of history. The existing legends of +flight, however, are not thus to be localised, for with two possible +exceptions they belong to all the world and to every civilisation, +however primitive. The two exceptions are the Aztec and the Chinese; +regarding the first of these, the Spanish conquistadores destroyed such +civilisation as existed in Tenochtitlan so thoroughly that, if legend +of flight was among the Aztec records, it went with the rest; as to the +Chinese, it is more than passing strange that they, who claim to have +known and done everything while the first of history was shaping, even +to antedating the discovery of gunpowder that was not made by Roger +Bacon, have not yet set up a claim to successful handling of a monoplane +some four thousand years ago, or at least to the patrol of the Gulf of +Korea and the Mongolian frontier by a forerunner of the 'blimp.' + +The Inca civilisation of Peru yields up a myth akin to that of Icarus, +which tells how the chieftain Ayar Utso grew wings and visited the +sun--it was from the sun, too, that the founders of the Peruvian Inca +dynasty, Manco Capac and his wife Mama Huella Capac, flew to earth near +Lake Titicaca, to make the only successful experiment in pure tyranny +that the world has ever witnessed. Teutonic legend gives forth Wieland +the Smith, who made himself a dress with wings and, clad in it, rose +and descended against the wind and in spite of it. Indian mythology, in +addition to the story of the demons and their rigid dirigible, already +quoted, gives the story of Hanouam, who fitted himself with wings by +means of which he sailed in the air and, according to his desire, landed +in the sacred Lauka. Bladud, the ninth king of Britain, is said to have +crowned his feats of wizardry by making himself wings and attempting +to fly--but the effort cost him a broken neck. Bladud may have been as +mythic as Uther, and again he may have been a very early pioneer. The +Finnish epic, 'Kalevala,' tells how Ilmarinen the Smith 'forged an eagle +of fire,' with 'boat's walls between the wings,' after which he 'sat +down on the bird's back and bones,' and flew. + +Pure myths, these, telling how the desire to fly was characteristic of +every age and every people, and how, from time to time, there arose an +experimenter bolder than his fellows, who made some attempt to translate +desire into achievement. And the spirit that animated these pioneers, +in a time when things new were accounted things accursed, for the most +part, has found expression in this present century in the utter daring +and disregard of both danger and pain that stamps the flying man, a type +of humanity differing in spirit from his earthbound fellows as fully as +the soldier differs from the priest. + +Throughout mediaeval times, records attest that here and there some man +believed in and attempted flight, and at the same time it is clear that +such were regarded as in league with the powers of evil. There is the +half-legend, half-history of Simon the Magician, who, in the third year +of the reign of Nero announced that he would raise himself in the air, +in order to assert his superiority over St Paul. The legend states that +by the aid of certain demons whom he had prevailed on to assist him, he +actually lifted himself in the air--but St Paul prayed him down again. +He slipped through the claws of the demons and fell headlong on the +Forum at Rome, breaking his neck. The 'demons' may have been some +primitive form of hot-air balloon, or a glider with which the magician +attempted to rise into the wind; more probably, however, Simon +threatened to ascend and made the attempt with apparatus as unsuitable +as Bladud's wings, paying the inevitable penalty. Another version of the +story gives St Peter instead of St Paul as the one whose prayers foiled +Simon--apart from the identity of the apostle, the two accounts are +similar, and both define the attitude of the age toward investigation +and experiment in things untried. + +Another and later circumstantial story, with similar evidence of some +fact behind it, is that of the Saracen of Constantinople, who, in the +reign of the Emperor Comnenus--some little time before Norman William +made Saxon Harold swear away his crown on the bones of the saints at +Rouen--attempted to fly round the hippodrome at Constantinople, having +Comnenus among the great throng who gathered to witness the feat. +The Saracen chose for his starting-point a tower in the midst of the +hippodrome, and on the top of the tower he stood, clad in a long white +robe which was stiffened with rods so as to spread and catch the breeze, +waiting for a favourable wind to strike on him. The wind was so long in +coming that the spectators grew impatient. 'Fly, O Saracen!' they +called to him. 'Do not keep us waiting so long while you try the wind!' +Comnenus, who had present with him the Sultan of the Turks, gave it +as his opinion that the experiment was both dangerous and vain, and, +possibly in an attempt to controvert such statement, the Saracen leaned +into the wind and 'rose like a bird 'at the outset. But the record of +Cousin, who tells the story in his Histoire de Constantinople, states +that 'the weight of his body having more power to drag him down than his +artificial wings had to sustain him, he broke his bones, and his evil +plight was such that he did not long survive.' + +Obviously, the Saracen was anticipating Lilienthal and his gliders by +some centuries; like Simon, a genuine experimenter--both legends +bear the impress of fact supporting them. Contemporary with him, and +belonging to the history rather than the legends of flight, was Oliver, +the monk of Malmesbury, who in the year 1065 made himself wings after +the pattern of those supposed to have been used by Daedalus, attaching +them to his hands and feet and attempting to fly with them. Twysden, in +his Historiae Anglicanae Scriptores X, sets forth the story of Oliver, +who chose a high tower as his starting-point, and launched himself in +the air. As a matter of course, he fell, permanently injuring himself, +and died some time later. + +After these, a gap of centuries, filled in by impossible stories of +magical flight by witches, wizards, and the like--imagination was +fertile in the dark ages, but the ban of the church was on all attempt +at scientific development, especially in such a matter as the conquest +of the air. Yet there were observers of nature who argued that since +birds could raise themselves by flapping their wings, man had only to +make suitable wings, flap them, and he too would fly. As early as +the thirteenth century Roger Bacon, the scientific friar of unbounded +inquisitiveness and not a little real genius, announced that there could +be made 'some flying instrument, so that a man sitting in the middle and +turning some mechanism may put in motion some artificial wings which +may beat the air like a bird flying.' But being a cautious man, with a +natural dislike for being burnt at the stake as a necromancer through +having put forward such a dangerous theory, Roger added, 'not that +I ever knew a man who had such an instrument, but I am particularly +acquainted with the man who contrived one.' This might have been a lame +defence if Roger had been brought to trial as addicted to black arts; he +seems to have trusted to the inadmissibility of hearsay evidence. + +Some four centuries later there was published a book entitled Perugia +Augusta, written by one C. Crispolti of Perugia--the date of the work in +question is 1648. In it is recorded that 'one day, towards the close of +the fifteenth century, whilst many of the principal gentry had come +to Perugia to honour the wedding of Giovanni Paolo Baglioni, and some +lancers were riding down the street by his palace, Giovanni Baptisti +Danti unexpectedly and by means of a contrivance of wings that he had +constructed proportionate to the size of his body took off from the top +of a tower near by, and with a horrible hissing sound flew successfully +across the great Piazza, which was densely crowded. But (oh, horror of +an unexpected accident!) he had scarcely flown three hundred paces on +his way to a certain point when the mainstay of the left wing gave way, +and, being unable to support himself with the right alone, he fell on a +roof and was injured in consequence. Those who saw not only this flight, +but also the wonderful construction of the framework of the wings, +said--and tradition bears them out--that he several times flew over the +waters of Lake Thrasimene to learn how he might gradually come to earth. +But, notwithstanding his great genius, he never succeeded.' + +This reads circumstantially enough, but it may be borne in mind that the +date of writing is more than half a century later than the time of the +alleged achievement--the story had had time to round itself out. Danti, +however, is mentioned by a number of writers, one of whom states that +the failure of his experiment was due to the prayers of some individual +of a conservative turn of mind, who prayed so vigorously that Danti fell +appropriately enough on a church and injured himself to such an extent +as to put an end to his flying career. That Danti experimented, there +is little doubt, in view of the volume of evidence on the point, but the +darkness of the Middle Ages hides the real truth as to the results of +his experiments. If he had actually flown over Thrasimene, as alleged, +then in all probability both Napoleon and Wellington would have had air +scouts at Waterloo. + +Danti's story may be taken as fact or left as fable, and with it the +period of legend or vague statement may be said to end--the rest is +history, both of genuine experimenters and of charlatans. Such instances +of legend as are given here are not a tithe of the whole, but there is +sufficient in the actual history of flight to bar out more than this +brief mention of the legends, which, on the whole, go farther to prove +man's desire to fly than his study and endeavour to solve the problems +of the air. + + + + +II. EARLY EXPERIMENTS + +So far, the stories of the development of flight are either legendary +or of more or less doubtful authenticity, even including that of Danti, +who, although a man of remarkable attainments in more directions +than that of attempted flight, suffers--so far as reputation is +concerned--from the inexactitudes of his chroniclers; he may have soared +over Thrasimene, as stated, or a mere hop with an ineffectual glider may +have grown with the years to a legend of gliding flight. So far, too, +there is no evidence of the study that the conquest of the air demanded; +such men as made experiments either launched themselves in the air from +some height with made-up wings or other apparatus, and paid the penalty, +or else constructed some form of machine which would not leave the +earth, and then gave up. Each man followed his own way, and there was no +attempt--without the printing press and the dissemination of knowledge +there was little possibility of attempt--on the part of any one to +benefit by the failures of others. + +Legend and doubtful history carries up to the fifteenth century, and +then came Leonardo da Vinci, first student of flight whose work endures +to the present day. The world knows da Vinci as artist; his age knew him +as architect, engineer, artist, and scientist in an age when science was +a single study, comprising all knowledge from mathematics to medicine. +He was, of course, in league with the devil, for in no other way +could his range of knowledge and observation be explained by his +contemporaries; he left a Treatise on the Flight of Birds in which are +statements and deductions that had to be rediscovered when the Treatise +had been forgotten--da Vinci anticipated modern knowledge as Plato +anticipated modern thought, and blazed the first broad trail toward +flight. + +One Cuperus, who wrote a Treatise on the Excellence of Man, asserted +that da Vinci translated his theories into practice, and actually flew, +but the statement is unsupported. That he made models, especially on +the helicopter principle, is past question; these were made of paper and +wire, and actuated by springs of steel wire, which caused them to lift +themselves in the air. It is, however, in the theories which he put +forward that da Vinci's investigations are of greatest interest; these +prove him a patient as well as a keen student of the principles of +flight, and show that his manifold activities did not prevent him from +devoting some lengthy periods to observations of bird flight. + +'A bird,' he says in his Treatise, 'is an instrument working according +to mathematical law, which instrument it is within the capacity of man +to reproduce with all its movements, but not with a corresponding +degree of strength, though it is deficient only in power of maintaining +equilibrium. We may say, therefore, that such an instrument constructed +by man is lacking in nothing except the life of the bird, and this life +must needs be supplied from that of man. The life which resides in the +bird's members will, without doubt, better conform to their needs than +will that of a man which is separated from them, and especially in the +almost imperceptible movements which produce equilibrium. But since we +see that the bird is equipped for many apparent varieties of movement, +we are able from this experience to deduce that the most rudimentary +of these movements will be capable of being comprehended by man's +understanding, and that he will to a great extent be able to provide +against the destruction of that instrument of which he himself has +become the living principle and the propeller.' + +In this is the definite belief of da Vinci that man is capable of +flight, together with a far more definite statement of the principles by +which flight is to be achieved than any which had preceded it--and for +that matter, than many that have succeeded it. Two further extracts from +his work will show the exactness of his observations:-- + +'When a bird which is in equilibrium throws the centre of resistance of +the wings behind the centre of gravity, then such a bird will descend +with its head downward. This bird which finds itself in equilibrium +shall have the centre of resistance of the wings more forward than +the bird's centre of gravity; then such a bird will fall with its tail +turned toward the earth.' + +And again: 'A man, when flying, shall be free from the waist up, that he +may be able to keep himself in equilibrium as he does in a boat, so +that the centre of his gravity and of the instrument may set itself in +equilibrium and change when necessity requires it to the changing of the +centre of its resistance.' + +Here, in this last quotation, are the first beginnings of the inherent +stability which proved so great an advance in design, in this twentieth +century. But the extracts given do not begin to exhaust the range of +da Vinci's observations and deductions. With regard to bird flight, he +observed that so long as a bird keeps its wings outspread it cannot fall +directly to earth, but must glide down at an angle to alight--a small +thing, now that the principle of the plane in opposition to the air is +generally grasped, but da Vinci had to find it out. From observation +he gathered how a bird checks its own speed by opposing tail and wing +surface to the direction of flight, and thus alights at the proper +'landing speed.' He proved the existence of upward air currents by +noting how a bird takes off from level earth with wings outstretched and +motionless, and, in order to get an efficient substitute for the +natural wing, he recommended that there be used something similar to +the membrane of the wing of a bat--from this to the doped fabric of an +aeroplane wing is but a small step, for both are equally impervious to +air. Again, da Vinci recommended that experiments in flight be conducted +at a good height from the ground, since, if equilibrium be lost through +any cause, the height gives time to regain it. This recommendation, by +the way, received ample support in the training areas of war pilots. + +Man's muscles, said da Vinci, are fully sufficient to enable him to +fly, for the larger birds, he noted, employ but a small part of their +strength in keeping themselves afloat in the air--by this theory he +attempted to encourage experiment, just as, when his time came, Borelli +reached the opposite conclusion and discouraged it. That Borelli was +right--so far--and da Vinci wrong, detracts not at all from the repute +of the earlier investigator, who had but the resources of his age to +support investigations conducted in the spirit of ages after. + +His chief practical contributions to the science of flight--apart +from numerous drawings which have still a value--are the helicopter or +lifting screw, and the parachute. The former, as already noted, he +made and proved effective in model form, and the principle which he +demonstrated is that of the helicopter of to-day, on which sundry +experimenters work spasmodically, in spite of the success of the plane +with its driving propeller. As to the parachute, the idea was doubtless +inspired by observation of the effect a bird produced by pressure of its +wings against the direction of flight. + +Da Vinci's conclusions, and his experiments, were forgotten easily by +most of his contemporaries; his Treatise lay forgotten for nearly four +centuries, overshadowed, mayhap, by his other work. There was, however, +a certain Paolo Guidotti of Lucca, who lived in the latter half of the +sixteenth century, and who attempted to carry da Vinci's theories--one +of them, at least, into practice. For this Guidotti, who was by +profession an artist and by inclination an investigator, made for +himself wings, of which the framework was of whalebone; these he covered +with feathers, and with them made a number of gliding flights, attaining +considerable proficiency. He is said in the end to have made a flight of +about four hundred yards, but this attempt at solving the problem +ended on a house roof, where Guidotti broke his thigh bone. After that, +apparently, he gave up the idea of flight, and went back to painting. + +One other a Venetian architect named Veranzio, studied da Vinci's theory +of the parachute, and found it correct, if contemporary records and even +pictorial presentment are correct. Da Vinci showed his conception of a +parachute as a sort of inverted square bag; Veranzio modified this to a +'sort of square sail extended by four rods of equal size and having four +cords attached at the corners,' by means of which 'a man could without +danger throw himself from the top of a tower or any high place. For +though at the moment there may be no wind, yet the effort of his falling +will carry up the wind, which the sail will hold, by which means he does +not fall suddenly but descends little by little. The size of the sail +should be measured to the man.' By this last, evidently, Veranzio +intended to convey that the sheet must be of such content as would +enclose sufficient air to support the weight of the parachutist. + +Veranzio made his experiments about 1617-1618, but, naturally, they +carried him no farther than the mere descent to earth, and since a +descent is merely a descent, it is to be conjectured that he soon got +tired of dropping from high roofs, and took to designing architecture +instead of putting it to such a use. With the end of his experiments the +work of da Vinci in relation to flying became neglected for nearly four +centuries. + +Apart from these two experimenters, there is little to record in the +matter either of experiment or study until the seventeenth century. +Francis Bacon, it is true, wrote about flying in his Sylva Sylvarum, and +mentioned the subject in the New Atlantis, but, except for the insight +that he showed even in superficial mention of any specific subject, +he does not appear to have made attempt at serious investigation. +'Spreading of Feathers, thin and close and in great breadth will +likewise bear up a great Weight,' says Francis, 'being even laid without +Tilting upon the sides.' But a lesser genius could have told as much, +even in that age, and though the great Sir Francis is sometimes adduced +as one of the early students of the problems of flight, his writings +will not sustain the reputation. + +The seventeenth century, however, gives us three names, those of +Borelli, Lana, and Robert Hooke, all of which take definite place in +the history of flight. Borelli ranks as one of the great figures in the +study of aeronautical problems, in spite of erroneous deductions through +which he arrived at a purely negative conclusion with regard to the +possibility of human flight. + +Borelli was a versatile genius. Born in 1608, he was practically +contemporary with Francesco Lana, and there is evidence that he either +knew or was in correspondence with many prominent members of the Royal +Society of Great Britain, more especially with John Collins, Dr Wallis, +and Henry Oldenburgh, the then Secretary of the Society. He was author +of a long list of scientific essays, two of which only are responsible +for his fame, viz., Theorice Medicaearum Planetarum, published in +Florence, and the better known posthumous De Motu Animalium. The first +of these two is an astronomical study in which Borelli gives evidence of +an instinctive knowledge of gravitation, though no definite expression +is given of this. The second work, De Motu Animalium, deals with the +mechanical action of the limbs of birds and animals and with a theory of +the action of the internal organs. A section of the first part of +this work, called De Volatu, is a study of bird flight; it is quite +independent of Da Vinci's earlier work, which had been forgotten and +remained unnoticed until near on the beginning of practical flight. + +Marey, in his work, La Machine Animale, credits Borelli with the first +correct idea of the mechanism of flight. He says: 'Therefore we must be +allowed to render to the genius of Borelli the justice which is due +to him, and only claim for ourselves the merit of having furnished the +experimental demonstration of a truth already suspected.' In fact, all +subsequent studies on this subject concur in making Borelli the first +investigator who illustrated the purely mechanical theory of the action +of a bird's wings. + +Borelli's study is divided into a series of propositions in which he +traces the principles of flight, and the mechanical actions of the wings +of birds. The most interesting of these are the propositions in which he +sets forth the method in which birds move their wings during flight and +the manner in which the air offers resistance to the stroke of the wing. +With regard to the first of these two points he says: 'When birds in +repose rest on the earth their wings are folded up close against their +flanks, but when wishing to start on their flight they first bend their +legs and leap into the air. Whereupon the joints of their wings are +straightened out to form a straight line at right angles to the lateral +surface of the breast, so that the two wings, outstretched, are placed, +as it were, like the arms of a cross to the body of the bird. Next, +since the wings with their feathers attached form almost a plane +surface, they are raised slightly above the horizontal, and with a +most quick impulse beat down in a direction almost perpendicular to the +wing-plane, upon the underlying air; and to so intense a beat the air, +notwithstanding it to be fluid, offers resistance, partly by reason +of its natural inertia, which seeks to retain it at rest, and partly +because the particles of the air, compressed by the swiftness of the +stroke, resist this compression by their elasticity, just like the hard +ground. Hence the whole mass of the bird rebounds, making a fresh +leap through the air; whence it follows that flight is simply a motion +composed of successive leaps accomplished through the air. And I remark +that a wing can easily beat the air in a direction almost perpendicular +to its plane surface, although only a single one of the corners of the +humerus bone is attached to the scapula, the whole extent of its base +remaining free and loose, while the greater transverse feathers are +joined to the lateral skin of the thorax. Nevertheless the wing can +easily revolve about its base like unto a fan. Nor are there lacking +tendon ligaments which restrain the feathers and prevent them from +opening farther, in the same fashion that sheets hold in the sails of +ships. No less admirable is nature's cunning in unfolding and folding +the wings upwards, for she folds them not laterally, but by moving +upwards edgewise the osseous parts wherein the roots of the feathers are +inserted; for thus, without encountering the air's resistance the upward +motion of the wing surface is made as with a sword, hence they can be +uplifted with but small force. But thereafter when the wings are twisted +by being drawn transversely and by the resistance of the air, they are +flattened as has been declared and will be made manifest hereafter.' + +Then with reference to the resistance to the air of the wings he +explains: 'The air when struck offers resistance by its elastic virtue +through which the particles of the air compressed by the wing-beat +strive to expand again. Through these two causes of resistance the +downward beat of the wing is not only opposed, but even caused to recoil +with a reflex movement; and these two causes of resistance ever increase +the more the down stroke of the wing is maintained and accelerated. On +the other hand, the impulse of the wing is continuously diminished and +weakened by the growing resistance. Hereby the force of the wing and the +resistance become balanced; so that, manifestly, the air is beaten by +the wing with the same force as the resistance to the stroke.' + +He concerns himself also with the most difficult problem that confronts +the flying man of to-day, namely, landing effectively, and his remarks +on this subject would be instructive even to an air pilot of these days: +'Now the ways and means by which the speed is slackened at the end of +a flight are these. The bird spreads its wings and tail so that their +concave surfaces are perpendicular to the direction of motion; in this +way, the spreading feathers, like a ship's sail, strike against the +still air, check the speed, and so that most of the impetus may be +stopped, the wings are flapped quickly and strongly forward, inducing a +contrary motion, so that the bird absolutely or very nearly stops.' + +At the end of his study Borelli came to a conclusion which militated +greatly against experiment with any heavier-than-air apparatus, until +well on into the nineteenth century, for having gone thoroughly into the +subject of bird flight he states distinctly in his last proposition +on the subject that 'It is impossible that men should be able to fly +craftily by their own strength.' This statement, of course, remains true +up to the present day for no man has yet devised the means by which he +can raise himself in the air and maintain himself there by mere muscular +effort. + +From the time of Borelli up to the development of the steam engine it +may be said that flight by means of any heavier-than-air apparatus was +generally regarded as impossible, and apart from certain deductions +which a little experiment would have shown to be doomed to failure, this +method of flight was not followed up. It is not to be wondered at, when +Borelli's exaggerated estimate of the strength expended by birds in +proportion to their weight is borne in mind; he alleged that the motive +force in birds' wings is 10,000 times greater than the resistance of +their weight, and with regard to human flight he remarks:-- + +'When, therefore, it is asked whether men may be able to fly by their +own strength, it must be seen whether the motive power of the pectoral +muscles (the strength of which is indicated and measured by their size) +is proportionately great, as it is evident that it must exceed the +resistance of the weight of the whole human body 10,000 times, together +with the weight of enormous wings which should be attached to the arms. +And it is clear that the motive power of the pectoral muscles in men is +much less than is necessary for flight, for in birds the bulk and weight +of the muscles for flapping the wings are not less than a sixth part of +the entire weight of the body. Therefore, it would be necessary that +the pectoral muscles of a man should weigh more than a sixth part of the +entire weight of his body; so also the arms, by flapping with the wings +attached, should be able to exert a power 10,000 times greater than the +weight of the human body itself. But they are far below such excess, +for the aforesaid pectoral muscles do not equal a hundredth part of the +entire weight of a man. Wherefore either the strength of the muscles +ought to be increased or the weight of the human body must be decreased, +so that the same proportion obtains in it as exists in birds. Hence +it is deducted that the Icarian invention is entirely mythical because +impossible, for it is not possible either to increase a man's pectoral +muscles or to diminish the weight of the human body; and whatever +apparatus is used, although it is possible to increase the momentum, +the velocity or the power employed can never equal the resistance; and +therefore wing flapping by the contraction of muscles cannot give out +enough power to carry up the heavy body of a man.' + +It may be said that practically all the conclusions which Borelli +reached in his study were negative. Although contemporary with Lana, +he perceived the one factor which rendered Lana's project for flight by +means of vacuum globes an impossibility--he saw that no globe could +be constructed sufficiently light for flight, and at the same time +sufficiently strong to withstand the pressure of the outside atmosphere. +He does not appear to have made any experiments in flying on his +own account, having, as he asserts most definitely, no faith in any +invention designed to lift man from the surface of the earth. But his +work, from which only the foregoing short quotations can be given, is, +nevertheless, of indisputable value, for he settled the mechanics of +bird flight, and paved the way for those later investigators who had, +first, the steam engine, and later the internal combustion engine--two +factors in mechanical flight which would have seemed as impossible to +Borelli as would wireless telegraphy to a student of Napoleonic times. +On such foundations as his age afforded Borelli built solidly and +well, so that he ranks as one of the greatest--if not actually the +greatest--of the investigators into this subject before the age of +steam. + +The conclusion, that 'the motive force in birds' wings is apparently +ten thousand times greater than the resistance of their weight,' is +erroneous, of course, but study of the translation from which the +foregoing excerpt is taken will show that the error detracts very little +from the value of the work itself. Borelli sets out very definitely +the mechanism of flight, in such fashion that he who runs may read. His +reference to 'the use of a large vessel,' etc., concerns the suggestion +made by Francesco Lana, who antedated Borelli's publication of De Motu +Animalium by some ten years with his suggestion for an 'aerial ship,' as +he called it. Lana's mind shows, as regards flight, a more imaginative +twist; Borelli dived down into first causes, and reached mathematical +conclusions; Lana conceived a theory and upheld it--theoretically, since +the manner of his life precluded experiment. + +Francesco Lana, son of a noble family, was born in 1631; in 1647 he was +received as a novice into the Society of Jesus at Rome, and remained +a pious member of the Jesuit society until the end of his life. He was +greatly handicapped in his scientific investigations by the vows +of poverty which the rules of the Order imposed on him. He was more +scientist than priest all his life; for two years he held the post of +Professor of Mathematics at Ferrara, and up to the time of his death, +in 1687, he spent by far the greater part of his time in scientific +research, He had the dubious advantage of living in an age when one man +could cover the whole range of science, and this he seems to have +done very thoroughly. There survives an immense work of his entitled, +Magisterium Naturae et Artis, which embraces the whole field of +scientific knowledge as that was developed in the period in which Lana +lived. In an earlier work of his, published in Brescia in 1670, appears +his famous treatise on the aerial ship, a problem which Lana worked out +with thoroughness. He was unable to make practical experiments, and thus +failed to perceive the one insuperable drawback to his project--of which +more anon. + +Only extracts from the translation of Lana's work can be given here, but +sufficient can be given to show fully the means by which he designed to +achieve the conquest of the air. He begins by mention of the celebrated +pigeon of Archytas the Philosopher, and advances one or two theories +with regard to the way in which this mechanical bird was constructed, +and then he recites, apparently with full belief in it, the fable of +Regiomontanus and the eagle that he is said to have constructed to +accompany Charles V. on his entry into Nuremberg. In fact, Lana starts +his work with a study of the pioneers of mechanical flying up to his +own time, and then outlines his own devices for the construction of +mechanical birds before proceeding to detail the construction of the +aerial ship. Concerning primary experiments for this he says:-- + +'I will, first of all, presuppose that air has weight owing to the +vapours and halations which ascend from the earth and seas to a height +of many miles and surround the whole of our terraqueous globe; and this +fact will not be denied by philosophers, even by those who may have but +a superficial knowledge, because it can be proven by exhausting, if +not all, at any rate the greater part of, the air contained in a glass +vessel, which, if weighed before and after the air has been exhausted, +will be found materially reduced in weight. Then I found out how much +the air weighed in itself in the following manner. I procured a large +vessel of glass, whose neck could be closed or opened by means of a tap, +and holding it open I warmed it over a fire, so that the air inside it +becoming rarified, the major part was forced out; then quickly shutting +the tap to prevent the re-entry I weighed it; which done, I plunged its +neck in water, resting the whole of the vessel on the surface of the +water, then on opening the tap the water rose in the vessel and filled +the greater part of it. I lifted the neck out of the water, released the +water contained in the vessel, and measured and weighed its quantity and +density, by which I inferred that a certain quantity of air had come out +of the vessel equal in bulk to the quantity of water which had entered +to refill the portion abandoned by the air. I again weighed the vessel, +after I had first of all well dried it free of all moisture, and found +it weighed one ounce more whilst it was full of air than when it was +exhausted of the greater part, so that what it weighed more was a +quantity of air equal in volume to the water which took its place. The +water weighed 640 ounces, so I concluded that the weight of air compared +with that of water was 1 to 640--that is to say, as the water which +filled the vessel weighed 640 ounces, so the air which filled the same +vessel weighed one ounce.' + +Having thus detailed the method of exhausting air from a vessel, Lana +goes on to assume that any large vessel can be entirely exhausted of +nearly all the air contained therein. Then he takes Euclid's proposition +to the effect that the superficial area of globes increases in the +proportion of the square of the diameter, whilst the volume increases in +the proportion of the cube of the same diameter, and he considers that +if one only constructs the globe of thin metal, of sufficient size, and +exhausts the air in the manner that he suggests, such a globe will be so +far lighter than the surrounding atmosphere that it will not only +rise, but will be capable of lifting weights. Here is Lana's own way of +putting it:-- + +'But so that it may be enabled to raise heavier weights and to lift +men in the air, let us take double the quantity of copper, 1,232 square +feet, equal to 308 lbs. of copper; with this double quantity of copper +we could construct a vessel of not only double the capacity, but of +four times the capacity of the first, for the reason shown by my fourth +supposition. Consequently the air contained in such a vessel will be 718 +lbs. 4 2/3 ounces, so that if the air be drawn out of the vessel it +will be 410 lbs. 4 2/3 ounces lighter than the same volume of air, and, +consequently, will be enabled to lift three men, or at least two, should +they weigh more than eight pesi each. It is thus manifest that the +larger the ball or vessel is made, the thicker and more solid can the +sheets of copper be made, because, although the weight will increase, +the capacity of the vessel will increase to a greater extent and with it +the weight of the air therein, so that it will always be capable to lift +a heavier weight. From this it can be easily seen how it is possible to +construct a machine which, fashioned like unto a ship, will float on the +air.' + +With four globes of these dimensions Lana proposed to make an aerial +ship of the fashion shown in his quaint illustration. He is careful to +point out a method by which the supporting globes for the aerial ship +may be entirely emptied of air; (this is to be done by connecting to each +globe a tube of copper which is 'at least a length of 47 modern Roman +palm).' A small tap is to close this tube at the end nearest the globe, +and then vessel and tube are to be filled with water, after which the +tube is to be immersed in water and the tap opened, allowing the water +to run out of the vessel, while no air enters. The tap is then closed +before the lower end of the tube is removed from the water, leaving no +air at all in the globe or sphere. Propulsion of this airship was to be +accomplished by means of sails, and also by oars. + +Lana antedated the modern propeller, and realised that the air would +offer enough resistance to oars or paddle to impart motion to any vessel +floating in it and propelled by these means, although he did not realise +the amount of pressure on the air which would be necessary to accomplish +propulsion. As a matter of fact, he foresaw and provided against +practically all the difficulties that would be encountered in the +working, as well as the making, of the aerial ship, finally coming up +against what his religious training made an insuperable objection. This, +again, is best told in his own words:-- + +'Other difficulties I do not foresee that could prevail against this +invention, save one only, which to me seems the greatest of them all, +and that is that God would surely never allow such a machine to be +successful, since it would create many disturbances in the civil and +political governments of mankind.' + +He ends by saying that no city would be proof against surprise, while +the aerial ship could set fire to vessels at sea, and destroy houses, +fortresses, and cities by fire balls and bombs. In fact, at the end of +his treatise on the subject, he furnishes a pretty complete resume of +the activities of German Zeppelins. + +As already noted, Lana himself, owing to his vows of poverty, was +unable to do more than put his suggestions on paper, which he did with +a thoroughness that has procured him a place among the really great +pioneers of flying. + +It was nearly 200 years before any attempt was made to realise his +project; then, in 1843, M. Marey Monge set out to make the globes and +the ship as Lana detailed them. Monge's experiments cost him the sum +of 25,000 francs 75 centimes, which he expended purely from love +of scientific investigation. He chose to make his globes of brass, +about.004 in thickness, and weighing 1.465 lbs. to the square yard. +Having made his sphere of this metal, he lined it with two thicknesses +of tissue paper, varnished it with oil, and set to work to empty it of +air. This, however, he never achieved, for such metal is incapable of +sustaining the pressure of the outside air, as Lana, had he had the +means to carry out experiments, would have ascertained. M. Monge's +sphere could never be emptied of air sufficiently to rise from the +earth; it ended in the melting-pot, ignominiously enough, and all that +Monge got from his experiment was the value of the scrap metal and the +satisfaction of knowing that Lana's theory could never be translated +into practice. + +Robert Hooke is less conspicuous than either Borelli or Lana; his work, +which came into the middle of the seventeenth century, consisted of +various experiments with regard to flight, from which emerged 'a Module, +which by the help of Springs and Wings, raised and sustained itself in +the air.' This must be reckoned as the first model flying machine which +actually flew, except for da Vinci's helicopters; Hooke's model appears +to have been of the flapping-wing type--he attempted to copy the motion +of birds, but found from study and experiment that human muscles were +not sufficient to the task of lifting the human body. For that reason, +he says, 'I applied my mind to contrive a way to make artificial +muscles,' but in this he was, as he expresses it, 'frustrated of my +expectations.' Hooke's claim to fame rests mainly on his successful +model; the rest of his work is of too scrappy a nature to rank as a +serious contribution to the study of flight. + +Contemporary with Hooke was one Allard, who, in France, undertook to +emulate the Saracen of Constantinople to a certain extent. Allard was a +tight-rope dancer who either did or was said to have done short gliding +flights--the matter is open to question--and finally stated that he +would, at St Germains, fly from the terrace in the king's presence. He +made the attempt, but merely fell, as did the Saracen some centuries +before, causing himself serious injury. Allard cannot be regarded as a +contributor to the development of aeronautics in any way, and is only +mentioned as typical of the way in which, up to the time of the Wright +brothers, flying was regarded. Even unto this day there are many who +still believe that, with a pair of wings, man ought to be able to fly, +and that the mathematical data necessary to effective construction +simply do not exist. This attitude was reasonable enough in an +unlearned age, and Allard was one--a little more conspicuous than the +majority--among many who made experiment in ignorance, with more or less +danger to themselves and without practical result of any kind. + +The seventeenth century was not to end, however, without practical +experiment of a noteworthy kind in gliding flight. Among the recruits to +the ranks of pioneers was a certain Besnier, a locksmith of Sable, who +somewhere between 1675 and 1680 constructed a glider of which a crude +picture has come down to modern times. The apparatus, as will be seen, +consisted of two rods with hinged flaps, and the original designer of +the picture seems to have had but a small space in which to draw, since +obviously the flaps must have been much larger than those shown. Besnier +placed the rods on his shoulders, and worked the flaps by cords attached +to his hands and feet--the flaps opened as they fell, and closed as they +rose, so the device as a whole must be regarded as a sort of flapping +glider. Having by experiment proved his apparatus successful, Besnier +promptly sold it to a travelling showman of the period, and forthwith +set about constructing a second set, with which he made gliding flights +of considerable height and distance. Like Lilienthal, Besnier projected +himself into space from some height, and then, according to the +contemporary records, he was able to cross a river of considerable size +before coming to earth. It does not appear that he had any imitators, +or that any advantage whatever was taken of his experiments; the age was +one in which he would be regarded rather as a freak exhibitor than as +a serious student, and possibly, considering his origin and the sale of +his first apparatus to such a client, he regarded the matter himself as +more in the nature of an amusement than as a discovery. + +Borelli, coming at the end of the century, proved to his own +satisfaction and that of his fellows that flapping wing flight was an +impossibility; the capabilities of the plane were as yet undreamed, and +the prime mover that should make the plane available for flight was +deep in the womb of time. Da Vinci's work was forgotten--flight was an +impossibility, or at best such a useless show as Besnier was able to +give. + +The eighteenth century was almost barren of experiment. Emanuel +Swedenborg, having invented a new religion, set about inventing a flying +machine, and succeeded theoretically, publishing the result of his +investigations as follows:-- + +'Let a car or boat or some like object be made of light material such as +cork or bark, with a room within it for the operator. Secondly, in front +as well as behind, or all round, set a widely-stretched sail parallel to +the machine forming within a hollow or bend which could be reefed like +the sails of a ship. Thirdly, place wings on the sides, to be worked +up and down by a spiral spring, these wings also to be hollow below in +order to increase the force and velocity, take in the air, and make the +resistance as great as may be required. These, too, should be of light +material and of sufficient size; they should be in the shape of birds' +wings, or the sails of a windmill, or some such shape, and should be +tilted obliquely upwards, and made so as to collapse on the upward +stroke and expand on the downward. Fourth, place a balance or beam +below, hanging down perpendicularly for some distance with a small +weight attached to its end, pendent exactly in line with the centre of +gravity; the longer this beam is, the lighter must it be, for it must +have the same proportion as the well-known vectis or steel-yard. This +would serve to restore the balance of the machine if it should lean over +to any of the four sides. Fifthly, the wings would perhaps have greater +force, so as to increase the resistance and make the flight easier, if +a hood or shield were placed over them, as is the case with certain +insects. Sixthly, when the sails are expanded so as to occupy a great +surface and much air, with a balance keeping them horizontal, only a +small force would be needed to move the machine back and forth in a +circle, and up and down. And, after it has gained momentum to move +slowly upwards, a slight movement and an even bearing would keep it +balanced in the air and would determine its direction at will.' + +The only point in this worthy of any note is the first device for +maintaining stability automatically--Swedenborg certainly scored a point +there. For the rest, his theory was but theory, incapable of being put +to practice--he does not appear to have made any attempt at advance +beyond the mere suggestion. + +Some ten years before his time the state of knowledge with regard to +flying in Europe was demonstrated by an order granted by the King of +Portugal to Friar Lourenzo de Guzman, who claimed to have invented a +flying machine capable of actual flight. The order stated that 'In +order to encourage the suppliant to apply himself with zeal toward +the improvement of the new machine, which is capable of producing the +effects mentioned by him, I grant unto him the first vacant place in +my College of Barcelos or Santarem, and the first professorship of +mathematics in my University of Coimbra, with the annual pension of +600,000 reis during his life.--Lisbon, 17th of March, 1709.' + +What happened to Guzman when the non-existence of the machine was +discovered is one of the things that is well outside the province of +aeronautics. He was charlatan pure and simple, as far as actual flight +was concerned, though he had some ideas respecting the design of hot-air +balloons, according to Tissandier. (La Navigation Aerienne.) His +flying machine was to contain, among other devices, bellows to produce +artificial wind when the real article failed, and also magnets in globes +to draw the vessel in an upward direction and maintain its buoyancy. +Some draughtsman, apparently gifted with as vivid imagination as Guzman +himself, has given to the world an illustration of the hypothetical +vessel; it bears some resemblance to Lana's aerial ship, from which fact +one draws obvious conclusions. + +A rather amusing claim to solving the problem of flight was made in the +middle of the eighteenth century by one Grimaldi, a 'famous and unique +Engineer' who, as a matter of actual fact, spent twenty years in +missionary work in India, and employed the spare time that missionary +work left him in bringing his invention to a workable state. The +invention is described as a 'box which with the aid of clockwork rises +in the air, and goes with such lightness and strong rapidity that it +succeeds in flying a journey of seven leagues in an hour. It is made in +the fashion of a bird; the wings from end to end are 25 feet in extent. +The body is composed of cork, artistically joined together and well +fastened with metal wire, covered with parchment and feathers. The +wings are made of catgut and whalebone, and covered also with the same +parchment and feathers, and each wing is folded in three seams. In the +body of the machine are contained thirty wheels of unique work, with two +brass globes and little chains which alternately wind up a counterpoise; +with the aid of six brass vases, full of a certain quantity of +quicksilver, which run in some pulleys, the machine is kept by the +artist in due equilibrium and balance. By means, then, of the friction +between a steel wheel adequately tempered and a very heavy and +surprising piece of lodestone, the whole is kept in a regulated forward +movement, given, however, a right state of the winds, since the machine +cannot fly so much in totally calm weather as in stormy. This prodigious +machine is directed and guided by a tail seven palmi long, which is +attached to the knees and ankles of the inventor by leather straps; by +stretching out his legs, either to the right or to the left, he moves +the machine in whichever direction he pleases.... The machine's +flight lasts only three hours, after which the wings gradually close +themselves, when the inventor, perceiving this, goes down gently, so as +to get on his own feet, and then winds up the clockwork and gets himself +ready again upon the wings for the continuation of a new flight. He +himself told us that if by chance one of the wheels came off or if one +of the wings broke, it is certain he would inevitably fall rapidly to +the ground, and, therefore, he does not rise more than the height of a +tree or two, as also he only once put himself in the risk of crossing +the sea, and that was from Calais to Dover, and the same morning he +arrived in London.' + +And yet there are still quite a number of people who persist in stating +that Bleriot was the first man to fly across the Channel! + +A study of the development of the helicopter principle was published +in France in 1868, when the great French engineer Paucton produced his +Theorie de la Vis d'Archimede. For some inexplicable reason, Paucton +was not satisfied with the term 'helicopter,' but preferred to call it +a 'pterophore,' a name which, so far as can be ascertained, has not been +adopted by any other writer or investigator. Paucton stated that, since +a man is capable of sufficient force to overcome the weight of his own +body, it is only necessary to give him a machine which acts on the air +'with all the force of which it is capable and at its utmost speed,' and +he will then be able to lift himself in the air, just as by the exertion +of all his strength he is able to lift himself in water. 'It would +seem,' says Paucton, 'that in the pterophore, attached vertically to a +carriage, the whole built lightly and carefully assembled, he has +found something that will give him this result in all perfection. In +construction, one would be careful that the machine produced the least +friction possible, and naturally it ought to produce little, as it would +not be at all complicated. The new Daedalus, sitting comfortably in his +carriage, would by means of a crank give to the pterophore a suitable +circular (or revolving) speed. This single pterophore would lift him +vertically, but in order to move horizontally he should be supplied with +a tail in the shape of another pterophore. When he wished to stop for a +little time, valves fixed firmly across the end of the space between +the blades would automatically close the openings through which the air +flows, and change the pterophore into an unbroken surface which +would resist the flow of air and retard the fall of the machine to a +considerable degree.' + +The doctrine thus set forth might appear plausible, but it is based on +the common misconception that all the force which might be put into the +helicopter or 'pterophore' would be utilised for lifting or propelling +the vehicle through the air, just as a propeller uses all its power to +drive a ship through water. But, in applying such a propelling force +to the air, most of the force is utilised in maintaining aerodynamic +support--as a matter of fact, more force is needed to maintain this +support than the muscle of man could possibly furnish to a lifting +screw, and even if the helicopter were applied to a full-sized, +engine-driven air vehicle, the rate of ascent would depend on the amount +of surplus power that could be carried. For example, an upward lift +of 1,000 pounds from a propeller 15 feet in diameter would demand an +expenditure of 50 horse-power under the best possible conditions, and in +order to lift this load vertically through such atmospheric pressure as +exists at sea-level or thereabouts, an additional 20 horsepower would be +required to attain a rate of 11 feet per second--50 horse-power must +be continually provided for the mere support of the load, and the +additional 20 horse-power must be continually provided in order to +lift it. Although, in model form, there is nothing quite so strikingly +successful as the helicopter in the range of flying machines, yet the +essential weight increases so disproportionately to the effective area +that it is necessary to go but very little beyond model dimensions for +the helicopter to become quite ineffective. + +That is not to say that the lifting screw must be totally ruled out +so far as the construction of aircraft is concerned. Much is still +empirical, so far as this branch of aeronautics is concerned, and +consideration of the structural features of a propeller goes to show +that the relations of essential weight and effective area do not +altogether apply in practice as they stand in theory. Paucton's dream, +in some modified form, may yet become reality--it is only so short +a time ago as 1896 that Lord Kelvin stated he had not the smallest +molecule of faith in aerial navigation, and since the whole history of +flight consists in proving the impossible possible, the helicopter may +yet challenge the propelled plane surface for aerial supremacy. + +It does not appear that Paucton went beyond theory, nor is there in his +theory any advance toward practical flight--da Vinci could have told +him as much as he knew. He was followed by Meerwein, who invented an +apparatus apparently something between a flapping wing machine and a +glider, consisting of two wings, which were to be operated by means of a +rod; the venturesome one who would fly by means of this apparatus had to +lie in a horizontal position beneath the wings to work the rod. Meerwein +deserves a place of mention, however, by reason of his investigations +into the amount of surface necessary to support a given weight. Taking +that weight at 200 pounds--which would allow for the weight of a man +and a very light apparatus--he estimated that 126 square feet would be +necessary for support. His pamphlet, published at Basle in 1784, shows +him to have been a painstaking student of the potentialities of flight. + +Jean-Pierre Blanchard, later to acquire fame in connection with balloon +flight, conceived and described a curious vehicle, of which he even +announced trials as impending. His trials were postponed time after +time, and it appears that he became convinced in the end of the futility +of his device, being assisted to such a conclusion by Lalande, the +astronomer, who repeated Borelli's statement that it was impossible for +man ever to fly by his own strength. This was in the closing days of +the French monarchy, and the ascent of the Montgolfiers' first hot-air +balloon in 1783--which shall be told more fully in its place--put an +end to all French experiments with heavier-than-air apparatus, though in +England the genius of Cayley was about to bud, and even in France there +were those who understood that ballooning was not true flight. + + + + +III. SIR GEORGE CAYLEY--THOMAS WALKER + +On the fifth of June, 1783, the Montgolfiers' hot-air balloon rose at +Versailles, and in its rising divided the study of the conquest of the +air into two definite parts, the one being concerned with the +propulsion of gas lifted, lighter-than-air vehicles, and the other being +crystallised in one sentence by Sir George Cayley: 'The whole problem,' +he stated, 'is confined within these limits, viz.: to make a surface +support a given weight by the application of power to the resistance of +the air.' For about ten years the balloon held the field entirely, being +regarded as the only solution of the problem of flight that man could +ever compass. So definite for a time was this view on the eastern side +of the Channel that for some years practically all the progress that was +made in the development of power-driven planes was made in Britain. + +In 1800 a certain Dr Thomas Young demonstrated that certain curved +surfaces suspended by a thread moved into and not away from a horizontal +current of air, but the demonstration, which approaches perilously near +to perpetual motion if the current be truly horizontal, has never been +successfully repeated, so that there is more than a suspicion that +Young's air-current was NOT horizontal. Others had made and were making +experiments on the resistance offered to the air by flat surfaces, when +Cayley came to study and record, earning such a place among the pioneers +as to win the title of 'father of British aeronautics.' + +Cayley was a man in advance of his time, in many ways. Of independent +means, he made the grand tour which was considered necessary to the +education of every young man of position, and during this excursion he +was more engaged in studies of a semi-scientific character than in the +pursuits that normally filled such a period. His various writings prove +that throughout his life aeronautics was the foremost subject in his +mind; the Mechanic's Magazine, Nicholson's Journal, the Philosophical +Magazine, and other periodicals of like nature bear witness to Cayley's +continued research into the subject of flight. He approached the subject +after the manner of the trained scientist, analysing the mechanical +properties of air under chemical and physical action. Then he set to +work to ascertain the power necessary for aerial flight, and was one of +the first to enunciate the fallacy of the hopes of successful flight by +means of the steam engine of those days, owing to the fact that it was +impossible to obtain a given power with a given weight. + +Yet his conclusions on this point were not altogether negative, for as +early as 1810 he stated that he could construct a balloon which could +travel with passengers at 20 miles an hour--he was one of the first to +consider the possibilities of applying power to a balloon. Nearly thirty +years later--in 1837--he made the first attempt at establishing an +aeronautical society, but at that time the power-driven plane was +regarded by the great majority as an absurd dream of more or less mad +inventors, while ballooning ranked on about the same level as tight-rope +walking, being considered an adjunct to fairs and fetes, more a pastime +than a study. + +Up to the time of his death, in 1857, Cayley maintained his study of +aeronautical matters, and there is no doubt whatever that his work +went far in assisting the solution of the problem of air conquest. His +principal published work, a monograph entitled Aerial Navigation, has +been republished in the admirable series of 'Aeronautical Classics' +issued by the Royal Aeronautical Society. He began this work by +pointing out the impossibility of flying by means of attached wings, an +impossibility due to the fact that, while the pectoral muscles of a bird +account for more than two-thirds of its whole muscular strength, in a +man the muscles available for flying, no matter what mechanism might be +used, would not exceed one-tenth of his total strength. + +Cayley did not actually deny the possibility of a man flying by muscular +effort, however, but stated that 'the flight of a strong man by great +muscular exertion, though a curious and interesting circumstance, +inasmuch as it will probably be the means of ascertaining finis power +and supplying the basis whereon to improve it, would be of little use.' + +From this he goes on to the possibility of using a Boulton and Watt +steam engine to develop the power necessary for flight, and in this he +saw a possibility of practical result. It is worthy of note that in +this connection he made mention of the forerunner of the modern internal +combustion engine; 'The French,' he said, 'have lately shown the great +power produced by igniting inflammable powders in closed vessels, +and several years ago an engine was made to work in this country in +a similar manner by inflammation of spirit of tar.' In a subsequent +paragraph of his monograph he anticipates almost exactly the +construction of the Lenoir gas engine, which came into being more than +fifty-five years after his monograph was published. + +Certain experiments detailed in his work were made to ascertain the +size of the surface necessary for the support of any given weight. +He accepted a truism of to-day in pointing out that in any matters +connected with aerial investigation, theory and practice are as +widely apart as the poles. Inclined at first to favour the helicopter +principle, he finally rejected this in favour of the plane, with which +he made numerous experiments. During these, he ascertained the peculiar +advantages of curved surfaces, and saw the necessity of providing both +vertical and horizontal rudders in order to admit of side steering +as well as the control of ascent and descent, and for preserving +equilibrium. He may be said to have anticipated the work of Lilienthal +and Pilcher, since he constructed and experimented with a fixed surface +glider. 'It was beautiful,' he wrote concerning this, 'to see this noble +white bird sailing majestically from the top of a hill to any given +point of the plain below it with perfect steadiness and safety, +according to the set of its rudder, merely by its own weight, descending +at an angle of about eight degrees with the horizon.' + +It is said that he once persuaded his gardener to trust himself in this +glider for a flight, but if Cayley himself ventured a flight in it he +has left no record of the fact. The following extract from his work, +Aerial Navigation, affords an instance of the thoroughness of his +investigations, and the concluding paragraph also shows his faith in the +ultimate triumph of mankind in the matter of aerial flight:-- + +'The act of flying requires less exertion than from the appearance is +supposed. Not having sufficient data to ascertain the exact degree of +propelling power exerted by birds in the act of flying, it is uncertain +what degree of energy may be required in this respect for vessels of +aerial navigation; yet when we consider the many hundreds of miles of +continued flight exerted by birds of passage, the idea of its being only +a small effort is greatly corroborated. To apply the power of the first +mover to the greatest advantage in producing this effect is a very +material point. The mode universally adopted by Nature is the oblique +waft of the wing. We have only to choose between the direct beat +overtaking the velocity of the current, like the oar of a boat, or +one applied like the wing, in some assigned degree of obliquity to it. +Suppose 35 feet per second to be the velocity of an aerial vehicle, the +oar must be moved with this speed previous to its being able to receive +any resistance; then if it be only required to obtain a pressure of +one-tenth of a lb. upon each square foot it must exceed the velocity of +the current 7.3 feet per second. Hence its whole velocity must be 42.5 +feet per second. Should the same surface be wafted downward like a wing +with the hinder edge inclined upward in an angle of about 50 deg. 40 +feet to the current it will overtake it at a velocity of 3.5 feet per +second; and as a slight unknown angle of resistance generates a lb. +pressure per square foot at this velocity, probably a waft of a little +more than 4 feet per second would produce this effect, one-tenth part +of which would be the propelling power. The advantage of this mode of +application compared with the former is rather more than ten to one. + +'In continuing the general principles of aerial navigation, for the +practice of the art, many mechanical difficulties present themselves +which require a considerable course of skilfully applied experiments +before they can be overcome; but, to a certain extent, the air has +already been made navigable, and no one who has seen the steadiness +with which weights to the amount of ten stone (including four stone, +the weight of the machine) hover in the air can doubt of the ultimate +accomplishment of this object.' + +This extract from his work gives but a faint idea of the amount of +research for which Cayley was responsible. He had the humility of the +true investigator in scientific problems, and so far as can be seen +was never guilty of the great fault of so many investigators in this +subject--that of making claims which he could not support. He was +content to do, and pass after having recorded his part, and although +nearly half a century had to pass between the time of his death and the +first actual flight by means of power-driven planes, yet he may be said +to have contributed very largely to the solution of the problem, and his +name will always rank high in the roll of the pioneers of flight. + +Practically contemporary with Cayley was Thomas Walker, concerning whom +little is known save that he was a portrait painter of Hull, where +was published his pamphlet on The Art of Flying in 1810, a second and +amplified edition being produced, also in Hull, in 1831. The pamphlet, +which has been reproduced in extenso in the Aeronautical Classics series +published by the Royal Aeronautical Society, displays a curious mixture +of the true scientific spirit and colossal conceit. Walker appears to +have been a man inclined to jump to conclusions, which carried him up to +the edge of discovery and left him vacillating there. + +The study of the two editions of his pamphlet side by side shows that +their author made considerable advances in the practicability of his +designs in the 21 intervening years, though the drawings which accompany +the text in both editions fail to show anything really capable +of flight. The great point about Walker's work as a whole is its +suggestiveness; he did not hesitate to state that the 'art' of flying is +as truly mechanical as that of rowing a boat, and he had some conception +of the necessary mechanism, together with an absolute conviction that he +knew all there was to be known. 'Encouraged by the public,' he says, +'I would not abandon my purpose of making still further exertions to +advance and complete an art, the discovery of the TRUE PRINCIPLES (the +italics are Walker's own) of which, I trust, I can with certainty affirm +to be my own.' + +The pamphlet begins with Walker's admiration of the mechanism of flight +as displayed by birds. 'It is now almost twenty years,' he says, 'since +I was first led to think, by the study of birds and their means of +flying, that if an artificial machine were formed with wings in exact +imitation of the mechanism of one of those beautiful living machines, +and applied in the very same way upon the air, there could be no doubt +of its being made to fly, for it is an axiom in philosophy that the same +cause will ever produce the same effect.' With this he confesses his +inability to produce the said effect through lack of funds, though he +clothes this delicately in the phrase 'professional avocations and other +circumstances.' Owing to this inability he published his designs that +others might take advantage of them, prefacing his own researches with +a list of the very early pioneers, and giving special mention to +Friar Bacon, Bishop Wilkins, and the Portuguese friar, De Guzman. But, +although he seems to suggest that others should avail themselves of +his theoretical knowledge, there is a curious incompleteness about the +designs accompanying his work, and about the work itself, which seems +to suggest that he had more knowledge to impart than he chose to make +public--or else that he came very near to complete solution of the +problem of flight, and stayed on the threshold without knowing it. + +After a dissertation upon the history and strength of the condor, and +on the differences between the weights of birds, he says: 'The following +observations upon the wonderful difference in the weight of some birds, +with their apparent means of supporting it in their flight, may tend +to remove some prejudices against my plan from the minds of some of +my readers. The weight of the humming-bird is one drachm, that of the +condor not less than four stone. Now, if we reduce four stone into +drachms we shall find the condor is 14,336 times as heavy as the +humming-bird. What an amazing disproportion of weight! Yet by the same +mechanical use of its wings the condor can overcome the specific gravity +of its body with as much ease as the little humming-bird. But this is +not all. We are informed that this enormous bird possesses a power in +its wings, so far exceeding what is necessary for its own conveyance +through the air, that it can take up and fly away with a whole sheer in +its talons, with as much ease as an eagle would carry off, in the same +manner, a hare or a rabbit. This we may readily give credit to, from the +known fact of our little kestrel and the sparrow-hawk frequently flying +off with a partridge, which is nearly three times the weight of these +rapacious little birds.' + +After a few more observations he arrives at the following conclusion: +'By attending to the progressive increase in the weight of birds, from +the delicate little humming-bird up to the huge condor, we clearly +discover that the addition of a few ounces, pounds, or stones, is no +obstacle to the art of flying; the specific weight of birds avails +nothing, for by their possessing wings large enough, and sufficient +power to work them, they can accomplish the means of flying equally well +upon all the various scales and dimensions which we see in nature. Such +being a fact, in the name of reason and philosophy why shall not man, +with a pair of artificial wings, large enough, and with sufficient power +to strike them upon the air, be able to produce the same effect?' + +Walker asserted definitely and with good ground that muscular effort +applied without mechanism is insufficient for human flight, but he +states that if an aeronautical boat were constructed so that a man could +sit in it in the same manner as when rowing, such a man would be able to +bring into play his whole bodily strength for the purpose of flight, +and at the same time would be able to get an additional advantage by +exerting his strength upon a lever. At first he concluded there must +be expansion of wings large enough to resist in a sufficient degree +the specific gravity of whatever is attached to them, but in the second +edition of his work he altered this to 'expansion of flat passive +surfaces large enough to reduce the force of gravity so as to float +the machine upon the air with the man in it.' The second requisite is +strength enough to strike the wings with sufficient force to complete +the buoyancy and give a projectile motion to the machine. Given +these two requisites, Walker states definitely that flying must be +accomplished simply by muscular exertion. 'If we are secure of these two +requisites, and I am very confident we are, we may calculate upon the +success of flight with as much certainty as upon our walking.' + +Walker appears to have gained some confidence from the experiments of a +certain M. Degen, a watchmaker of Vienna, who, according to the Monthly +Magazine of September, 1809, invented a machine by means of which a +person might raise himself into the air. The said machine, according to +the magazine, was formed of two parachutes which might be folded up or +extended at pleasure, while the person who worked them was placed in the +centre. This account, however, was rather misleading, for the magazine +carefully avoided mention of a balloon to which the inventor fixed his +wings or parachutes. Walker, knowing nothing of the balloon, concluded +that Degen actually raised himself in the air, though he is doubtful +of the assertion that Degen managed to fly in various directions, +especially against the wind. + +Walker, after considering Degen and all his works, proceeds to detail +his own directions for the construction of a flying machine, these +being as follows: 'Make a car of as light material as possible, but +with sufficient strength to support a man in it; provide a pair of wings +about four feet each in length; let them be horizontally expanded and +fastened upon the top edge of each side of the car, with two joints +each, so as to admit of a vertical motion to the wings, which motion may +be effected by a man sitting and working an upright lever in the middle +of the car. Extend in the front of the car a flat surface of silk, which +must be stretched out and kept fixed in a passive state; there must +be the same fixed behind the car; these two surfaces must be perfectly +equal in length and breadth and large enough to cover a sufficient +quantity of air to support the whole weight as nearly in equilibrium as +possible, thus we shall have a great sustaining power in those passive +surfaces and the active wings will propel the car forward.' + +A description of how to launch this car is subsequently given: 'It +becomes necessary,' says the theorist, 'that I should give directions +how it may be launched upon the air, which may be done by various means; +perhaps the following method may be found to answer as well as any: Fix +a poll upright in the earth, about twenty feet in height, with two open +collars to admit another poll to slide upwards through them; let there +be a sliding platform made fast upon the top of the sliding poll; place +the car with a man in it upon the platform, then raise the platform to +the height of about thirty feet by means of the sliding poll, let the +sliding poll and platform suddenly fall down, the car will then be +left upon the air, and by its pressing the air a projectile force will +instantly propel the car forward; the man in the car must then strike +the active wings briskly upon the air, which will so increase the +projectile force as to become superior to the force of gravitation, and +if he inclines his weight a little backward, the projectile impulse will +drive the car forward in an ascending direction. When the car is brought +to a sufficient altitude to clear the tops of hills, trees, buildings, +etc., the man, by sitting a little forward on his seat, will then bring +the wings upon a horizontal plane, and by continuing the action of the +wings he will be impelled forward in that direction. To descend, he +must desist from striking the wings, and hold them on a level with their +joints; the car will then gradually come down, and when it is within +five or six feet of the ground the man must instantly strike the wings +downwards, and sit as far back as he can; he will by this means check +the projectile force, and cause the car to alight very gently with a +retrograde motion. The car, when up in the air, may be made to turn +to the right or to the left by forcing out one of the fins, having one +about eighteen inches long placed vertically on each side of the car for +that purpose, or perhaps merely by the man inclining the weight of his +body to one side.' + +Having stated how the thing is to be done, Walker is careful to explain +that when it is done there will be in it some practical use, notably in +respect of the conveyance of mails and newspapers, or the saving of +life at sea, or for exploration, etc. It might even reduce the number of +horses kept by man for his use, by means of which a large amount of land +might be set free for the growth of food for human consumption. + +At the end of his work Walker admits the idea of steam power for driving +a flying machine in place of simple human exertion, but he, like Cayley, +saw a drawback to this in the weight of the necessary engine. On the +whole, he concluded, navigation of the air by means of engine power +would be mostly confined to the construction of navigable balloons. + +As already noted, Walker's work is not over practical, and the foregoing +extract includes the most practical part of it; the rest is a series +of dissertations on bird flight, in which, evidently, the portrait +painter's observations were far less thorough than those of da Vinci or +Borelli. Taken on the whole, Walker was a man with a hobby; he devoted +to it much time and thought, but it remained a hobby, nevertheless. His +observations have proved useful enough to give him a place among the +early students of flight, but a great drawback to his work is the lack +of practical experiment, by means of which alone real advance could +be made; for, as Cayley admitted, theory and practice are very widely +separated in the study of aviation, and the whole history of flight is +a matter of unexpected results arising from scarcely foreseen causes, +together with experiment as patient as daring. + + + + +IV. THE MIDDLE NINETEENTH CENTURY + +Both Cayley and Walker were theorists, though Cayley supported his +theoretical work with enough of practice to show that he studied along +right lines; a little after his time there came practical men +who brought to being the first machine which actually flew by the +application of power. Before their time, however, mention must be made +of the work of George Pocock of Bristol, who, somewhere about 1840 +invented what was described as a 'kite carriage,' a vehicle which +carried a number of persons, and obtained its motive power from a large +kite. It is on record that, in the year 1846 one of these carriages +conveyed sixteen people from Bristol to London. Another device of +Pocock's was what he called a 'buoyant sail,' which was in effect a +man-lifting kite, and by means of which a passenger was actually raised +100 yards from the ground, while the inventor's son scaled a cliff +200 feet in height by means of one of these, 'buoyant sails.' This +constitutes the first definitely recorded experiment in the use of +man-lifting kites. A History of the Charvolant or Kite-carriage, +published in London in 1851, states that 'an experiment of a bold and +very novel character was made upon an extensive down, where a large +wagon with a considerable load was drawn along, whilst this huge machine +at the same time carried an observer aloft in the air, realising almost +the romance of flying.' + +Experimenting, two years after the appearance of the 'kite-carriage,' +on the helicopter principle, W. H. Phillips constructed a model machine +which weighed two pounds; this was fitted with revolving fans, driven +by the combustion of charcoal, nitre, and gypsum, producing steam which, +discharging into the air, caused the fans to revolve. The inventor +stated that 'all being arranged, the steam was up in a few seconds, when +the whole apparatus spun around like any top, and mounted into the +air faster than a bird; to what height it ascended I had no means of +ascertaining; the distance travelled was across two fields, where, after +a long search, I found the machine minus the wings, which had been +torn off in contact with the ground.' This could hardly be described as +successful flight, but it was an advance in the construction of machines +on the helicopter principle, and it was the first steam-driven model of +the type which actually flew. The invention, however, was not followed +up. + +After Phillips, we come to the great figures of the middle nineteenth +century, W. S. Henson and John Stringfellow. Cayley had shown, in +1809, how success might be attained by developing the idea of the plane +surface so driven as to take advantage of the resistance offered by +the air, and Henson, who as early as 1840 was experimenting with model +gliders and light steam engines, evolved and patented an idea for +something very nearly resembling the monoplane of the early twentieth +century. His patent, No. 9478, of the year 1842 explains the principle +of the machine as follows:-- + +In order that the description hereafter given be rendered clear, I will +first shortly explain the principle on which the machine is constructed. +If any light and flat or nearly flat article be projected or thrown +edgewise in a slightly inclined position, the same will rise on the +air till the force exerted is expended, when the article so thrown or +projected will descend; and it will readily be conceived that, if the +article so projected or thrown possessed in itself a continuous power or +force equal to that used in throwing or projecting it, the article +would continue to ascend so long as the forward part of the surface was +upwards in respect to the hinder part, and that such article, when the +power was stopped, or when the inclination was reversed, would descend +by gravity aided by the force of the power contained in the article, if +the power be continued, thus imitating the flight of a bird. + +Now, the first part of my invention consists of an apparatus so +constructed as to offer a very extended surface or plane of a light yet +strong construction, which will have the same relation to the general +machine which the extended wings of a bird have to the body when a bird +is skimming in the air; but in place of the movement or power for onward +progress being obtained by movement of the extended surface or plane, as +is the case with the wings of birds, I apply suitable paddle-wheels +or other proper mechanical propellers worked by a steam or other +sufficiently light engine, and thus obtain the requisite power for +onward movement to the plane or extended surface; and in order to give +control as to the upward and downward direction of such a machine I +apply a tail to the extended surface which is capable of being inclined +or raised, so that when the power is acting to propel the machine, by +inclining the tail upwards, the resistance offered by the air will +cause the machine to rise on the air; and, on the contrary, when the +inclination of the tail is reversed, the machine will immediately be +propelled downwards, and pass through a plane more or less inclined to +the horizon as the inclination of the tail is greater or less; and in +order to guide the machine as to the lateral direction which it shall +take, I apply a vertical rudder or second tail, and, according as the +same is inclined in one direction or the other, so will be the direction +of the machine.' + +The machine in question was very large, and differed very little from +the modern monoplane; the materials were to be spars of bamboo and +hollow wood, with diagonal wire bracing. The surface of the planes was +to amount to 4,500 square feet, and the tail, triangular in form (here +modern practice diverges) was to be 1,500 square feet. The inventor +estimated that there would be a sustaining power of half a pound per +square foot, and the driving power was to be supplied by a steam engine +of 25 to 30 horse-power, driving two six-bladed propellers. Henson was +largely dependent on Stringfellow for many details of his design, more +especially with regard to the construction of the engine. + +The publication of the patent attracted a great amount of public +attention, and the illustrations in contemporary journals, representing +the machine flying over the pyramids and the Channel, anticipated fact +by sixty years and more; the scientific world was divided, as it was +up to the actual accomplishment of flight, as to the value of the +invention. + +Strongfellow and Henson became associated after the conception of their +design, with an attorney named Colombine, and a Mr Marriott, and +between the four of them a project grew for putting the whole thing on +a commercial basis--Henson and Stringfellow were to supply the idea; +Marriott, knowing a member of Parliament, would be useful in getting a +company incorporated, and Colombine would look after the purely legal +side of the business. Thus an application was made by Mr Roebuck, +Marriott's M.P., for an act of incorporation for 'The Aerial Steam +Transit Company,' Roebuck moving to bring in the bill on the 24th of +March, 1843. The prospectus, calling for funds for the development of +the invention, makes interesting reading at this stage of aeronautical +development; it was as follows: + + PROPOSAL. + +For subscriptions of sums of L100, in furtherance of an Extraordinary +Invention not at present safe to be developed by securing the necessary +Patents, for which three times the sum advanced, namely, L300, is +conditionally guaranteed for each subscription on February 1, 1844, +in case of the anticipations being realised, with the option of the +subscribers being shareholders for the large amount if so desired, but +not otherwise. + +---------An Invention has recently been discovered, which if ultimately +successful will be without parallel even in the age which introduced to +the world the wonderful effects of gas and of steam. + +The discovery is of that peculiar nature, so simple in principle yet +so perfect in all the ingredients required for complete and permanent +success, that to promulgate it at present would wholly defeat its +development by the immense competition which would ensue, and the views +of the originator be entirely frustrated. + +This work, the result of years of labour and study, presents a wonderful +instance of the adaptation of laws long since proved to the scientific +world combined with established principles so judiciously and carefully +arranged, as to produce a discovery perfect in all its parts and alike +in harmony with the laws of Nature and of science. + +The Invention has been subjected to several tests and examinations +and the results are most satisfactory so much so that nothing but the +completion of the undertaking is required to determine its practical +operation, which being once established its utility is undoubted, as it +would be a necessary possession of every empire, and it were hardly too +much to say, of every individual of competent means in the civilised +world. + +Its qualities and capabilities are so vast that it were impossible and, +even if possible, unsafe to develop them further, but some idea may +be formed from the fact that as a preliminary measure patents in Great +Britain Ireland, Scotland, the Colonies, France, Belgium, and the +United States, and every other country where protection to the first +discoveries of an Invention is granted, will of necessity be immediately +obtained, and by the time these are perfected, which it is estimated +will be in the month of February, the Invention will be fit for Public +Trial, but until the Patents are sealed any further disclosure would be +most dangerous to the principle on which it is based. + +Under these circumstances, it is proposed to raise an immediate sum of +L2,000 in furtherance of the Projector's views, and as some protection +to the parties who may embark in the matter, that this is not a +visionary plan for objects imperfectly considered, Mr Colombine, to whom +the secret has been confided, has allowed his name to be used on the +occasion, and who will if referred to corroborate this statement, and +convince any inquirer of the reasonable prospects of large pecuniary +results following the development of the Invention. + +It is, therefore, intended to raise the sum of L2,000 in twenty sums of +L100 each (of which any subscriber may take one or more not exceeding +five in number to be held by any individual) the amount of which is to +be paid into the hands of Mr Colombine as General Manager of the concern +to be by him appropriated in procuring the several Patents and providing +the expenses incidental to the works in progress. For each of which +sums of L100 it is intended and agreed that twelve months after the +1st February next, the several parties subscribing shall receive as an +equivalent for the risk to be run the sum of L300 for each of the sums +of L100 now subscribed, provided when the time arrives the Patents shall +be found to answer the purposes intended. + +As full and complete success is alone looked to, no moderate or +imperfect benefit is to be anticipated, but the work, if it once passes +the necessary ordeal, to which inventions of every kind must be first +subject, will then be regarded by every one as the most astonishing +discovery of modern times; no half success can follow, and therefore the +full nature of the risk is immediately ascertained. + +The intention is to work and prove the Patent by collective instead of +individual aid as less hazardous at first end more advantageous in the +result for the Inventor, as well as others, by having the interest of +several engaged in aiding one common object--the development of a +Great Plan. The failure is not feared, yet as perfect success might, by +possibility, not ensue, it is necessary to provide for that result, +and the parties concerned make it a condition that no return of +the subscribed money shall be required, if the Patents shall by any +unforeseen circumstances not be capable of being worked at all; against +which, the first application of the money subscribed, that of securing +the Patents, affords a reasonable security, as no one without solid +grounds would think of such an expenditure. + +It is perfectly needless to state that no risk or responsibility of any +kind can arise beyond the payment of the sum to be subscribed under any +circumstances whatever. + +As soon as the Patents shall be perfected and proved it is contemplated, +so far as may be found practicable, to further the great object in view +a Company shall be formed but respecting which it is unnecessary to +state further details, than that a preference will be given to all those +persons who now subscribe, and to whom shares shall be appropriated +according to the larger amount (being three times the sum to be paid by +each person) contemplated to be returned as soon as the success of the +Invention shall have been established, at their option, or the money +paid, whereby the Subscriber will have the means of either withdrawing +with a large pecuniary benefit, or by continuing his interest in the +concern lay the foundation for participating in the immense benefit +which must follow the success of the plan. + +It is not pretended to conceal that the project is a speculation--all +parties believe that perfect success, and thence incalculable advantage +of every kind, will follow to every individual joining in this great +undertaking; but the Gentlemen engaged in it wish that no concealment +of the consequences, perfect success, or possible failure, should in the +slightest degree be inferred. They believe this will prove the germ of a +mighty work, and in that belief call for the operation of others with no +visionary object, but a legitimate one before them, to attain that point +where perfect success will be secured from their combined exertions. + +All applications to be made to D. E. Colombine, Esquire, 8 Carlton +Chambers, Regent Street. + +The applications did not materialise, as was only to be expected in view +of the vagueness of the proposals. Colombine did some advertising, and +Mr Roebuck expressed himself as unwilling to proceed further in the +venture. Henson experimented with models to a certain extent, while +Stringfellow looked for funds for the construction of a full-sized +monoplane. In November of 1843 he suggested that he and Henson should +construct a large model out of their own funds. On Henson's suggestion +Colombine and Marriott were bought out as regards the original patent, +and Stringfellow and Henson entered into an agreement and set to work. + +Their work is briefly described in a little pamphlet by F. J. +Stringfellow, entitled A few Remarks on what has been done with +screw-propelled Aero-plane Machines from 1809 to 1892. The author writes +with regard to the work that his father and Henson undertook:-- + +'They commenced the construction of a small model operated by a spring, +and laid down the larger model 20 ft. from tip to tip of planes, 3 1/2 +ft. wide, giving 70 ft. of sustaining surface, about 10 more in the +tail. The making of this model required great consideration; various +supports for the wings were tried, so as to combine lightness with +firmness, strength and rigidity. + +'The planes were staid from three sets of fish-shaped masts, and rigged +square and firm by flat steel rigging. The engine and boiler were put in +the car to drive two screw-propellers, right and left-handed, 3 ft. in +diameter, with four blades each, occupying three-quarters of the area +of the circumference, set at an angle of 60 degrees. A considerable time +was spent in perfecting the motive power. Compressed air was tried and +abandoned. Tappets, cams, and eccentrics were all tried, to work the +slide valve, to obtain the best results. The piston rod of engine passed +through both ends of the cylinder, and with long connecting rods worked +direct on the crank of the propellers. From memorandum of experiments +still preserved the following is a copy of one: June, 27th, 1845, water +50 ozs., spirit 10 ozs., lamp lit 8.45, gauge moves 8.46, engine started +8.48 (100 lb. pressure), engine stopped 8.57, worked 9 minutes, 2,288 +revolutions, average 254 per minute. No priming, 40 ozs. water consumed, +propulsion (thrust of propellers), 5 lbs. 4 1/2 ozs. at commencement, +steady, 4 lbs. 1/2 oz., 57 revolutions to 1 oz. water, steam cut off +one-third from beginning. + +'The diameter of cylinder of engine was 1 1/2 inch, length of stroke 3 +inches. + +'In the meantime an engine was also made for the smaller model, and a +wing action tried, but with poor results. The time was mostly devoted to +the larger model, and in 1847 a tent was erected on Bala Down, about two +miles from Chard, and the model taken up one night by the workmen. The +experiments were not so favourable as was expected. The machine could +not support itself for any distance, but, when launched off, gradually +descended, although the power and surface should have been ample; +indeed, according to latest calculations, the thrust should have carried +more than three times the weight, for there was a thrust of 5 lbs. from +the propellers, and a surface of over 70 square feet to sustain under 30 +lbs., but necessary speed was lacking.' + +Stringfellow himself explained the failure as follows:-- + +'There stood our aerial protegee in all her purity--too delicate, too +fragile, too beautiful for this rough world; at least those were +my ideas at the time, but little did I think how soon it was to be +realised. I soon found, before I had time to introduce the spark, a +drooping in the wings, a flagging in all the parts. In less than ten +minutes the machine was saturated with wet from a deposit of dew, so +that anything like a trial was impossible by night. I did not consider +we could get the silk tight and rigid enough. Indeed, the framework +altogether was too weak. The steam-engine was the best part. Our want of +success was not for want of power or sustaining surface, but for want of +proper adaptation of the means to the end of the various parts.' + +Henson, who had spent a considerable amount of money in these +experimental constructions, consoled himself for failure by venturing +into matrimony; in 1849 he went to America, leaving Stringfellow to +continue experimenting alone. From 1846 to 1848 Stringfellow worked on +what is really an epoch-making item in the history of aeronautics--the +first engine-driven aeroplane which actually flew. The machine in +question had a 10 foot span, and was 2 ft. across in the widest part of +the wing; the length of tail was 3 ft. 6 ins., and the span of tail in +the widest part 22 ins., the total sustaining area being about 14 +sq. ft. The motive power consisted of an engine with a cylinder of +three-quarter inch diameter and a two-inch stroke; between this and +the crank shaft was a bevelled gear giving three revolutions of the +propellers to every stroke of the engine; the propellers, right and left +screw, were four-bladed and 16 inches in diameter. The total weight of +the model with engine was 8 lbs. Its successful flight is ascribed to +the fact that Stringfellow curved the wings, giving them rigid front +edges and flexible trailing edges, as suggested long before both by Da +Vinci and Borelli, but never before put into practice. + +Mr F. J. Stringfellow, in the pamphlet quoted above, gives the best +account of the flight of this model: 'My father had constructed another +small model which was finished early in 1848, and having the loan of a +long room in a disused lace factory, early in June the small model was +moved there for experiments. The room was about 22 yards long and +from 10 to 12 ft. high.... The inclined wire for starting the machine +occupied less than half the length of the room and left space at the end +for the machine to clear the floor. In the first experiment the tail was +set at too high an angle, and the machine rose too rapidly on leaving +the wire. After going a few yards it slid back as if coming down an +inclined plane, at such an angle that the point of the tail struck the +ground and was broken. The tail was repaired and set at a smaller angle. +The steam was again got up, and the machine started down the wire, and, +upon reaching the point of self-detachment, it gradually rose until +it reached the farther end of the room, striking a hole in the canvas +placed to stop it. In experiments the machine flew well, when rising as +much as one in seven. The late Rev. J. Riste, Esq., lace manufacturer, +Northcote Spicer, Esq., J. Toms, Esq., and others witnessed experiments. +Mr Marriatt, late of the San Francisco News Letter brought down from +London Mr Ellis, the then lessee of Cremorne Gardens, Mr Partridge, and +Lieutenant Gale, the aeronaut, to witness experiments. Mr Ellis offered +to construct a covered way at Cremorne for experiments. Mr Stringfellow +repaired to Cremorne, but not much better accommodations than he had +at home were provided, owing to unfulfilled engagement as to room. +Mr Stringfellow was preparing for departure when a party of gentlemen +unconnected with the Gardens begged to see an experiment, and finding +them able to appreciate his endeavours, he got up steam and started the +model down the wire. When it arrived at the spot where it should leave +the wire it appeared to meet with some obstruction, and threatened to +come to the ground, but it soon recovered itself and darted off in +as fair a flight as it was possible to make at a distance of about 40 +yards, where it was stopped by the canvas. + +'Having now demonstrated the practicability of making a steam-engine +fly, and finding nothing but a pecuniary loss and little honour, +this experimenter rested for a long time, satisfied with what he had +effected. The subject, however, had to him special charms, and he still +contemplated the renewal of his experiments.' + +It appears that Stringfellow's interest did not revive sufficiently +for the continuance of the experiments until the founding of the +Aeronautical Society of Great Britain in 1866. Wenham's paper on Aerial +Locomotion read at the first meeting of the Society, which was held at +the Society of Arts under the Presidency of the Duke of Argyll, was +the means of bringing Stringfellow back into the field. It was Wenham's +suggestion, in the first place, that monoplane design should be +abandoned for the superposition of planes; acting on this suggestion +Stringfellow constructed a model triplane, and also designed a steam +engine of slightly over one horse-power, and a one horse-power copper +boiler and fire box which, although capable of sustaining a pressure of +500 lbs. to the square inch, weighed only about 40 lbs. + +Both the engine and the triplane model were exhibited at the first +Aeronautical Exhibition held at the Crystal Palace in 1868. The triplane +had a supporting surface of 28 sq. ft.; inclusive of engine, boiler, +fuel, and water its total weight was under 12 lbs. The engine worked two +21 in. propellers at 600 revolutions per minute, and developed 100 lbs. +steam pressure in five minutes, yielding one-third horse-power. Since +no free flight was allowed in the Exhibition, owing to danger from fire, +the triplane was suspended from a wire in the nave of the building, +and it was noted that, when running along the wire, the model made a +perceptible lift. + +A prize of L100 was awarded to the steam engine as the lightest steam +engine in proportion to its power. The engine and model together may +be reckoned as Stringfellow's best achievement. He used his L100 in +preparation for further experiments, but he was now an old man, and +his work was practically done. Both the triplane and the engine were +eventually bought for the Washington Museum; Stringfellow's earlier +models, together with those constructed by him in conjunction with +Henson, remain in this country in the Victoria and Albert Museum. + +John Stringfellow died on December 13th, 1883. His place in the history +of aeronautics is at least equal to that of Cayley, and it may be +said that he laid the foundation of such work as was subsequently +accomplished by Maxim, Langley, and their fellows. It was the coming of +the internal combustion engine that rendered flight practicable, and had +this prime mover been available in John Stringfellow's day the Wright +brothers' achievement might have been antedated by half a century. + + + + +V. WENHAM, LE BRIS, AND SOME OTHERS + +There are few outstanding events in the development of aeronautics +between Stringfellow's final achievement and the work of such men as +Lilienthal, Pilcher, Montgomery, and their kind; in spite of this, the +later middle decades of the nineteenth century witnessed a considerable +amount of spade work both in England and in France, the two countries +which led in the way in aeronautical development until Lilienthal gave +honour to Germany, and Langley and Montgomery paved the way for the +Wright Brothers in America. + +Two abortive attempts characterised the sixties of last century in +France. As regards the first of these, it was carried out by three men, +Nadar, Ponton d'Amecourt, and De la Landelle, who conceived the idea +of a full-sized helicopter machine. D'Amecourt exhibited a steam model, +constructed in 1865, at the Aeronautical Society's Exhibition in 1868. +The engine was aluminium with cylinders of bronze, driving two screws +placed one above the other and rotating in Opposite directions, but the +power was not sufficient to lift the model. De la Landelle's principal +achievement consisted in the publication in 1863 of a book entitled +Aviation which has a certain historical value; he got out several +designs for large machines on the helicopter principle, but did little +more until the three combined in the attempt to raise funds for the +construction of their full-sized machine. Since the funds were not +forthcoming, Nadar took to ballooning as the means of raising money; +apparently he found this substitute for real flight sufficiently +interesting to divert him from the study of the helicopter principle, +for the experiment went no further. + +The other experimenter of this period, one Count d'Esterno, took out a +patent in 1864 for a soaring machine which allowed for alteration of +the angle of incidence of the wings in the manner that was subsequently +carried out by the Wright Brothers. It was not until 1883 that any +attempt was made to put this patent to practical use, and, as the +inventor died while it was under construction, it was never completed. +D'Esterno was also responsible for the production of a work entitled +Du Vol des Oiseaux, which is a very remarkable study of the flight of +birds. + +Mention has already been made of the founding of the Aeronautical +Society of Great Britain, which, since 1918 has been the Royal +Aeronautical Society. 1866 witnessed the first meeting of the Society +under the Presidency of the Duke of Argyll, when in June, at the Society +of Arts, Francis Herbert Wenham read his now classic paper Aerial +Locomotion. Certain quotations from this will show how clearly Wenham +had thought out the problems connected with flight. + +'The first subject for consideration is the proportion of surface to +weight, and their combined effect in descending perpendicularly through +the atmosphere. The datum is here based upon the consideration of +safety, for it may sometimes be needful for a living being to drop +passively, without muscular effort. One square foot of sustaining +surface for every pound of the total weight will be sufficient for +security. + +'According to Smeaton's table of atmospheric resistances, to produce +a force of one pound on a square foot, the wind must move against the +plane (or which is the same thing, the plane against the wind), at the +rate of twenty-two feet per second, or 1,320 feet per minute, equal to +fifteen miles per hour. The resistance of the air will now balance the +weight on the descending surface, and, consequently, it cannot exceed +that speed. Now, twenty-two feet per second is the velocity acquired at +the end of a fall of eight feet--a height from which a well-knit man or +animal may leap down without much risk of injury. Therefore, if a man +with parachute weigh together 143 lbs., spreading the same number of +square feet of surface contained in a circle fourteen and a half feet +in diameter, he will descend at perhaps an unpleasant velocity, but with +safety to life and limb. + +'It is a remarkable fact how this proportion of wing-surface to weight +extends throughout a great variety of the flying portion of the +animal kingdom, even down to hornets, bees, and other insects. In some +instances, however, as in the gallinaceous tribe, including pheasants, +this area is somewhat exceeded, but they are known to be very poor +fliers. Residing as they do chiefly on the ground, their wings are +only required for short distances, or for raising them or easing their +descent from their roosting-places in forest trees, the shortness +of their wings preventing them from taking extended flights. The +wing-surface of the common swallow is rather more than in the ratio of +two square feet per pound, but having also great length of pinion, it is +both swift and enduring in its flight. When on a rapid course this bird +is in the habit of furling its wings into a narrow compass. The greater +extent of surface is probably needful for the continual variations of +speed and instant stoppages for obtaining its insect food. + +'On the other hand, there are some birds, particularly of the duck +tribe, whose wing-surface but little exceeds half a square foot, +or seventy-two inches per pound, yet they may be classed among the +strongest and swiftest of fliers. A weight of one pound, suspended +from an area of this extent, would acquire a velocity due to a fall of +sixteen feet--a height sufficient for the destruction or injury of most +animals. But when the plane is urged forward horizontally, in a manner +analogous to the wings of a bird during flight, the sustaining power is +greatly influenced by the form and arrangement of the surface. + +'In the case of perpendicular descent, as a parachute, the sustaining +effect will be much the same, whatever the figure of the outline of the +superficies may be, and a circle perhaps affords the best resistance of +any. Take, for example, a circle of twenty square feet (as possessed +by the pelican) loaded with as many pounds. This, as just stated, will +limit the rate of perpendicular descent to 1,320 feet per minute. But +instead of a circle sixty-one inches in diameter, if the area is bounded +by a parallelogram ten feet long by two feet broad, and whilst at +perfect freedom to descend perpendicularly, let a force be applied +exactly in a horizontal direction, so as to carry it edgeways, with the +long side foremost, at a forward speed of thirty miles per hour--just +double that of its passive descent: the rate of fall under these +conditions will be decreased most remarkably, probably to less than +one-fifteenth part, or eighty-eight feet per minute, or one mile per +hour.' + +And again: 'It has before been shown how utterly inadequate the mere +perpendicular impulse of a plane is found to be in supporting a weight, +when there is no horizontal motion at the time. There is no material +weight of air to be acted upon, and it yields to the slightest force, +however great the velocity of impulse may be. On the other hand, suppose +that a large bird, in full flight, can make forty miles per hour, or +3,520 feet per minute, and performs one stroke per second. Now, during +every fractional portion of that stroke, the wing is acting upon and +obtaining an impulse from a fresh and undisturbed body of air; and if +the vibration of the wing is limited to an arc of two feet, this by no +means represents the small force of action that would be obtained when +in a stationary position, for the impulse is secured upon a stratum of +fifty-eight feet in length of air at each stroke. So that the conditions +of weight of air for obtaining support equally well apply to weight of +air and its reaction in producing forward impulse. + +'So necessary is the acquirement of this horizontal speed, even in +commencing flight, that most heavy birds, when possible, rise against +the wind, and even run at the top of their speed to make their wings +available, as in the example of the eagle, mentioned at the commencement +of this paper. It is stated that the Arabs, on horseback, can approach +near enough to spear these birds, when on the plain, before they are +able to rise; their habit is to perch on an eminence, where possible. + +'The tail of a bird is not necessary for flight. A pigeon can fly +perfectly with this appendage cut short off; it probably performs an +important function in steering, for it is to be remarked, that most +birds that have either to pursue or evade pursuit are amply provided +with this organ. + +'The foregoing reasoning is based upon facts, which tend to show that +the flight of the largest and heaviest of all birds is really performed +with but a small amount of force, and that man is endowed with +sufficient muscular power to enable him also to take individual and +extended flights, and that success is probably only involved in a +question of suitable mechanical adaptations. But if the wings are to be +modelled in imitation of natural examples, but very little consideration +will serve to demonstrate its utter impracticability when applied in +these forms.' + +Thus Wenham, one of the best theorists of his age. The Society with +which this paper connects his name has done work, between that time and +the present, of which the importance cannot be overestimated, and has +been of the greatest value in the development of aeronautics, both in +theory and experiment. The objects of the Society are to give a stronger +impulse to the scientific study of aerial navigation, to promote the +intercourse of those interested in the subject at home and abroad, and +to give advice and instruction to those who study the principles upon +which aeronautical science is based. From the date of its foundation the +Society has given special study to dynamic flight, putting this before +ballooning. Its library, its bureau of advice and information, and its +meetings, all assist in forwarding the study of aeronautics, and its +twenty-three early Annual Reports are of considerable value, containing +as they do a large amount of useful information on aeronautical +subjects, and forming practically the basis of aeronautical science. + +Ante to Wenham, Stringfellow and the French experimenters already noted, +by some years, was Le Bris, a French sea captain, who appears to have +required only a thorough scientific training to have rendered him of +equal moment in the history of gliding flight with Lilienthal himself. +Le Bris, it appears, watched the albatross and deduced, from the manner +in which it supported itself in the air, that plane surfaces could +be constructed and arranged to support a man in like manner. Octave +Chanute, himself a leading exponent of gliding, gives the best +description of Le Bris's experiments in a work, Progress in Flying +Machines, which, although published as recently as I 1894, is already +rare. Chanute draws from a still rarer book, namely, De la Landelle's +work published in 1884. Le Bris himself, quoted by De la Landelle as +speaking of his first visioning of human flight, describes how he killed +an albatross, and then--'I took the wing of the albatross and exposed +it to the breeze; and lo! in spite of me it drew forward into the wind; +notwithstanding my resistance it tended to rise. Thus I had discovered +the secret of the bird! I comprehended the whole mystery of flight.' + +This apparently took place while at sea; later on Le Bris, returning to +France, designed and constructed an artificial albatross of sufficient +size to bear his own weight. The fact that he followed the bird outline +as closely as he did attests his lack of scientific training for his +task, while at the same time the success of the experiment was proof of +his genius. The body of his artificial bird, boat-shaped, was 13 1/2 ft. +in length, with a breadth of 4 ft. at the widest part. The material +was cloth stretched over a wooden framework; in front was a small mast +rigged after the manner of a ship's masts to which were attached poles +and cords with which Le Bris intended to work the wings. Each wing was +23 ft. in length, giving a total supporting surface of nearly 220 sq. +ft.; the weight of the whole apparatus was only 92 pounds. For steering, +both vertical and horizontal, a hinged tail was provided, and the +leading edge of each wing was made flexible. In construction throughout, +and especially in that of the wings, Le Bris adhered as closely as +possible to the original albatross. + +He designed an ingenious kind of mechanism which he termed 'Rotules,' +which by means of two levers gave a rotary motion to the front edge of +the wings, and also permitted of their adjustment to various angles. +The inventor's idea was to stand upright in the body of the contrivance, +working the levers and cords with his hands, and with his feet on +a pedal by means of which the steering tail was to be worked. He +anticipated that, given a strong wind, he could rise into the air after +the manner of an albatross, without any need for flapping his wings, and +the account of his first experiment forms one of the most interesting +incidents in the history of flight. It is related in full in Chanute's +work, from which the present account is summarised. + +Le Bris made his first experiment on a main road near Douarnenez, at +Trefeuntec. From his observation of the albatross Le Bris concluded +that it was necessary to get some initial velocity in order to make the +machine rise; consequently on a Sunday morning, with a breeze of about +12 miles an hour blowing down the road, he had his albatross placed on a +cart and set off, with a peasant driver, against the wind. At the outset +the machine was fastened to the cart by a rope running through the rails +on which the machine rested, and secured by a slip knot on Le Bris's own +wrist, so that only a jerk on his part was necessary to loosen the rope +and set the machine free. On each side walked an assistant holding the +wings, and when a turn of the road brought the machine full into the +wind these men were instructed to let go, while the driver increased the +pace from a walk to a trot. Le Bris, by pressure on the levers of the +machine, raised the front edges of his wings slightly; they took the +wind almost instantly to such an extent that the horse, relieved of a +great part of the weight he had been drawing, turned his trot into a +gallop. Le Bris gave the jerk of the rope that should have unfastened +the slip knot, but a concealed nail on the cart caught the rope, so that +it failed to run. The lift of the machine was such, however, that it +relieved the horse of very nearly the weight of the cart and driver, as +well as that of Le Bris and his machine, and in the end the rails of the +cart gave way. Le Bris rose in the air, the machine maintaining perfect +balance and rising to a height of nearly 300 ft., the total length of +the glide being upwards of an eighth of a mile. But at the last moment +the rope which had originally fastened the machine to the cart got wound +round the driver's body, so that this unfortunate dangled in the air +under Le Bris and probably assisted in maintaining the balance of the +artificial albatross. Le Bris, congratulating himself on his success, +was prepared to enjoy just as long a time in the air as the pressure of +the wind would permit, but the howls of the unfortunate driver at the +end of the rope beneath him dispelled his dreams; by working his levers +he altered the angle of the front wing edges so skilfully as to make a +very successful landing indeed for the driver, who, entirely uninjured, +disentangled himself from the rope as soon as he touched the ground, and +ran off to retrieve his horse and cart. + +Apparently his release made a difference in the centre of gravity, for +Le Bris could not manipulate his levers for further ascent; by skilful +manipulation he retarded the descent sufficiently to escape injury to +himself; the machine descended at an angle, so that one wing, striking +the ground in front of the other, received a certain amount of damage. + +It may have been on account of the reluctance of this same or another +driver that Le Bris chose a different method of launching himself in +making a second experiment with his albatross. He chose the edge of a +quarry which had been excavated in a depression of the ground; here he +assembled his apparatus at the bottom of the quarry, and by means of a +rope was hoisted to a height of nearly 100 ft. from the quarry bottom, +this rope being attached to a mast which he had erected upon the edge +of the depression in which the quarry was situated. Thus hoisted, the +albatross was swung to face a strong breeze that blew inland, and Le +Bris manipulated his levers to give the front edges of his wings a +downward angle, so that only the top surfaces should take the wing +pressure. Having got his balance, he obtained a lifting angle of +incidence on the wings by means of his levers, and released the hook +that secured the machine, gliding off over the quarry. On the glide he +met with the inevitable upward current of air that the quarry and the +depression in which it was situated caused; this current upset the +balance of the machine and flung it to the bottom of the quarry, +breaking it to fragments. Le Bris, apparently as intrepid as ingenious, +gripped the mast from which his levers were worked, and, springing +upward as the machine touched earth, escaped with no more damage than a +broken leg. But for the rebound of the levers he would have escaped even +this. + +The interest of these experiments is enhanced by the fact that Le Bris +was a seafaring man who conducted them from love of the science which +had fired his imagination, and in so doing exhausted his own small +means. It was in 1855 that he made these initial attempts, and +twelve years passed before his persistence was rewarded by a public +subscription made at Brest for the purpose of enabling him to continue +his experiments. He built a second albatross, and on the advice of his +friends ballasted it for flight instead of travelling in it himself. It +was not so successful as the first, probably owing to the lack of human +control while in flight; on one of the trials a height of 150 ft. was +attained, the glider being secured by a thin rope and held so as to face +into the wind. A glide of nearly an eighth of a mile was made with the +rope hanging slack, and, at the end of this distance, a rise in the +ground modified the force of the wind, whereupon the machine settled +down without damage. A further trial in a gusty wind resulted in the +complete destruction of this second machine; Le Bris had no more +funds, no further subscriptions were likely to materialise, and so +the experiments of this first exponent of the art of gliding (save +for Besnier and his kind) came to an end. They constituted a notable +achievement, and undoubtedly Le Bris deserves a better place than has +been accorded him in the ranks of the early experimenters. + +Contemporary with him was Charles Spencer, the first man to practice +gliding in England. His apparatus consisted of a pair of wings with a +total area of 30 sq. ft., to which a tail and body were attached. The +weight of this apparatus was some 24 lbs., and, launching himself on +it from a small eminence, as was done later by Lilienthal in his +experiments, the inventor made flights of over 120 feet. The glider in +question was exhibited at the Aeronautical Exhibition of 1868. + + + + +VI. THE AGE OF THE GIANTS + +Until the Wright Brothers definitely solved the problem of flight and +virtually gave the aeroplane its present place in aeronautics, there +were three definite schools of experiment. The first of these was +that which sought to imitate nature by means of the ornithopter or +flapping-wing machines directly imitative of bird flight; the second +school was that which believed in the helicopter or lifting screw; the +third and eventually successful school is that which followed up the +principle enunciated by Cayley, that of opposing a plane surface to the +resistance of the air by supplying suitable motive power to drive it at +the requisite angle for support. + +Engineering problems generally go to prove that too close an imitation +of nature in her forms of recipro-cating motion is not advantageous; it +is impossible to copy the minutiae of a bird's wing effectively, and the +bird in flight depends on the tiniest details of its feathers just as +much as on the general principle on which the whole wing is constructed. +Bird flight, however, has attracted many experimenters, including even +Lilienthal; among others may be mentioned F. W. Brearey, who invented +what he called the 'Pectoral cord,' which stored energy on each upstroke +of the artificial wing; E. P. Frost; Major R. Moore, and especially +Hureau de Villeneuve, a most enthusiastic student of this form of +flight, who began his experiments about 1865, and altogether designed +and made nearly 300 artificial birds, one of his later constructions +was a machine in bird form with a wing span of about 50 ft.; the +motive power for this was supplied by steam from a boiler which, being +stationary on the ground, was connected by a length of hose to the +machine. De Villeneuve, turning on steam for his first trial, obtained +sufficient power to make the wings beat very forcibly; with the inventor +on the machine the latter rose several feet into the air, whereupon de +Villeneuve grew nervous and turned off the steam supply. The machine +fell to the earth, breaking one of its wings, and it does not appear +that de Villeneuve troubled to reconstruct it. This experiment remains +as the greatest success yet achieved by any machine constructed on the +ornithopter principle. + +It may be that, as forecasted by the prophet Wells, the flapping-wing +machine will yet come to its own and compete with the aeroplane in +efficiency. Against this, however, are the practical advantages of +the rotary mechanism of the aeroplane propeller as compared with the +movement of a bird's wing, which, according to Marey, moves in a figure +of eight. The force derived from a propeller is of necessity continual, +while it is equally obvious that that derived from a flapping movement +is intermittent, and, in the recovery of a wing after completion of one +stroke for the next, there is necessarily a certain cessation, if not +loss, of power. + +The matter of experiment along any lines in connection with aviation is +primarily one of hard cash. Throughout the whole history of flight up to +the outbreak of the European war development has been handicapped on +the score of finance, and, since the arrival of the aeroplane, both +ornithopter and helicopter schools have been handicapped by this +consideration. Thus serious study of the efficiency of wings in +imitation of those of the living bird has not been carried to a point +that might win success for this method of propulsion. Even Wilbur Wright +studied this subject and propounded certain theories, while a later and +possibly more scientific student, F. W. Lanchester, has also contributed +empirical conclusions. Another and earlier student was Lawrence +Hargrave, who made a wing-propelled model which achieved successful +flight, and in 1885 was exhibited before the Royal Society of New South +Wales. Hargrave called the principle on which his propeller worked that +of a 'Trochoided plane'; it was, in effect, similar to the feathering of +an oar. + +Hargrave, to diverge for a brief while from the machine to the man, +was one who, although he achieved nothing worthy of special remark, +contributed a great deal of painstaking work to the science of flight. +He made a series of experiments with man-lifting kites in addition to +making a study of flapping-wing flight. It cannot be said that he set +forth any new principle; his work was mainly imitative, but at the same +time by developing ideas originated in great measure by others he helped +toward the solution of the problem. + +Attempts at flight on the helicopter principle consist in the work of De +la Landelle and others already mentioned. The possibility of flight by +this method is modified by a very definite disadvantage of which lovers +of the helicopter seem to take little account. It is always claimed for +a machine of this type that it possesses great advantages both in rising +and in landing, since, if it were effective, it would obviously be able +to rise from and alight on any ground capable of containing its own +bulk; a further advantage claimed is that the helicopter would be able +to remain stationary in the air, maintaining itself in any position by +the vertical lift of its propeller. + +These potential assets do not take into consideration the fact that +efficiency is required not only in rising, landing, and remaining +stationary in the air, but also in actual flight. It must be evident +that if a certain amount of the motive force is used in maintaining the +machine off the ground, that amount of force is missing from the total +of horizontal driving power. Again, it is often assumed by advocates of +this form of flight that the rapidity of climb of the helicopter would +be far greater than that of the driven plane; this view overlooks the +fact that the maintenance of aerodynamic support would claim the greater +part of the engine-power; the rate of ascent would be governed by the +amount of power that could be developed surplus to that required for +maintenance. + +This is best explained by actual figures: assuming that a propeller 15 +ft. in diameter is used, almost 50 horse-power would be required to +get an upward lift of 1,000 pounds; this amount of horse-power would be +continually absorbed in maintaining the machine in the air at any given +level; for actual lift from one level to another at a speed of eleven +feet per second a further 20 horse-power would be required, which means +that 70 horse-power must be constantly provided for; this absorption +of power in the mere maintenance of aero-dynamic support is a permanent +drawback. + +The attraction of the helicopter lies, probably, in the ease with which +flight is demonstrated by means of models constructed on this principle, +but one truism with regard to the principles of flight is that the +problems change remarkably, and often unexpectedly, with the size of +the machine constructed for experiment. Berriman, in a brief but very +interesting manual entitled Principles of Flight, assumed that 'there is +a significant dimension of which the effective area is an expression +of the second power, while the weight became an expression of the third +power. Then once again we have the two-thirds power law militating +against the successful construction of large helicopters, on the ground +that the essential weight increases disproportionately fast to the +effective area. From a consideration of the structural features of +propellers it is evident that this particular relationship does not +apply in practice, but it seems reasonable that some such governing +factor should exist as an explanation of the apparent failure of all +full-sized machines that have been constructed. Among models there is +nothing more strikingly successful than the toy helicopter, in which the +essential weight is so small compared with the effective area.' + +De la Landelle's work, already mentioned, was carried on a few years +later by another Frenchman, Castel, who constructed a machine with eight +propellers arranged in two fours and driven by a compressed air motor or +engine. The model with which Castel experimented had a total weight of +only 49 lbs.; it rose in the air and smashed itself by driving against +a wall, and the inventor does not seem to have proceeded further. +Contemporary with Castel was Professor Forlanini, whose design was for +a machine very similar to de la Landelle's, with two superposed screws. +This machine ranks as the second on the helicopter principle to achieve +flight; it remained in the air for no less than the third of a minute in +one of its trials. + +Later experimenters in this direction were Kress, a German; Professor +Wellner, an Austrian; and W. R. Kimball, an American. Kress, like most +Germans, set to the development of an idea which others had originated; +he followed de la Landelle and Forlanini by fitting two superposed +propellers revolving in opposite directions, and with this machine he +achieved good results as regards horse-power to weight; Kimball, it +appears, did not get beyond the rubber-driven model stage, and any +success he may have achieved was modified by the theory enunciated by +Berriman and quoted above. + +Comparing these two schools of thought, the helicopter and bird-flight +schools, it appears that the latter has the greater chance of eventual +success--that is, if either should ever come into competition with the +aeroplane as effective means of flight. So far, the aeroplane holds +the field, but the whole science of flight is so new and so full of +unexpected developments that this is no reason for assuming that other +means may not give equal effect, when money and brains are diverted from +the driven plane to a closer imitation of natural flight. + +Reverting from non-success to success, from consideration of the two +methods mentioned above to the direction in which practical flight +has been achieved, it is to be noted that between the time of Le +Bris, Stringfellow, and their contemporaries, and the nineties of last +century, there was much plodding work carried out with little visible +result, more especially so far as English students were concerned. Among +the incidents of those years is one of the most pathetic tragedies in +the whole history of aviation, that of Alphonse Penaud, who, in his +thirty years of life, condensed the experience of his predecessors and +combined it with his own genius to state in a published patent what +the aeroplane of to-day should be. Consider the following abstract of +Penaud's design as published in his patent of 1876, and comparison of +this with the aeroplane that now exists will show very few divergences +except for those forced on the inventor by the fact that the internal +combustion engine had not then developed. The double surfaced planes +were to be built with wooden ribs and arranged with a slight dihedral +angle; there was to be a large aspect ratio and the wings were cambered +as in Stringfellow's later models. Provision was made for warping the +wings while in flight, and the trailing edges were so designed as to +be capable of upward twist while the machine was in the air. The planes +were to be placed above the car, and provision was even made for a glass +wind-screen to give protection to the pilot during flight. Steering was +to be accomplished by means of lateral and vertical planes forming +a tail; these controlled by a single lever corresponding to the 'joy +stick' of the present day plane. + +Penaud conceived this machine as driven by two propellers; alternatively +these could be driven by petrol or steam-fed motor, and the centre of +gravity of the machine while in flight was in the front fifth of the +wings. Penaud estimated from 20 to 30 horse-power sufficient to drive +this machine, weighing with pilot and passenger 2,600 lbs., through the +air at a speed of 60 miles an hour, with the wings set at an angle +of incidence of two degrees. So complete was the design that it even +included instruments, consisting of an aneroid, pressure indicator, an +anemometer, a compass, and a level. There, with few alterations, is the +aeroplane as we know it--and Penaud was twenty-seven when his patent was +published. + +For three years longer he worked, experimenting with models, +contributing essays and other valuable data to French papers on the +subject of aeronautics. His gains were ill health, poverty, and neglect, +and at the age of thirty a pistol shot put an end to what had promised +to be one of the most brilliant careers in all the history of flight. + +Two years before the publication of Penaud's patent Thomas Moy +experimented at the Crystal Palace with a twin-propelled aeroplane, +steam driven, which seems to have failed mainly because the internal +combustion engine had not yet come to give sufficient power for weight. +Moy anchored his machine to a pole running on a prepared circular track; +his engine weighed 80 lbs. and, developing only three horse-power, gave +him a speed of 12 miles an hour. He himself estimated that the machine +would not rise until he could get a speed of 35 miles an hour, and his +estimate was correct. Two six-bladed propellers were placed side by side +between the two main planes of the machine, which was supported on a +triangular wheeled undercarriage and steered by fairly conventional tail +planes. Moy realised that he could not get sufficient power to achieve +flight, but he went on experimenting in various directions, and left +much data concerning his experiments which has not yet been deemed +worthy of publication, but which still contains a mass of information +that is of practical utility, embodying as it does a vast amount of +painstaking work. + +Penaud and Moy were followed by Goupil, a Frenchman, who, in place of +attempting to fit a motor to an aeroplane, experimented by making the +wind his motor. He anchored his machine to the ground, allowing it two +feet of lift, and merely waited for a wind to come along and lift it. +The machine was stream lined, and the wings, curving as in the early +German patterns of war aeroplanes, gave a total lifting surface of about +290 sq. ft. Anchored to the ground and facing a wind of 19 feet per +second, Goupil's machine lifted its own weight and that of two men as +well to the limit of its anchorage. Although this took place as late +as 1883 the inventor went no further in practical work. He published a +book, however, entitled La Locomotion Aerienne, which is still of great +importance, more especially on the subject of inherent stability. + +In 1884 came the first patents of Horatio Phillips, whose work lay +mainly in the direction of investigation into the curvature of plane +surfaces, with a view to obtaining the greatest amount of support. +Phillips was one of the first to treat the problem of curvature of +planes as a matter for scientific experiment, and, great as has been the +development of the driven plane in the 36 years that have passed since +he began, there is still room for investigation into the subject which +he studied so persistently and with such valuable result. + +At this point it may be noted that, with the solitary exception of +Le Bris, practically every student of flight had so far set about +constructing the means of launching humanity into the air without any +attempt at ascertaining the nature and peculiarities of the sustaining +medium. The attitude of experimenters in general might be compared to +that of a man who from boyhood had grown up away from open water, and, +at the first sight of an expanse of water, set to work to construct a +boat with a vague idea that, since wood would float, only sufficient +power was required to make him an efficient navigator. Accident, +perhaps, in the shape of lack of means of procuring driving power, drove +Le Bris to the form of experiment which he actually carried out; it +remained for the later years of the nineteenth century to produce men +who were content to ascertain the nature of the support the air would +afford before attempting to drive themselves through it. + +Of the age in which these men lived and worked, giving their all in many +cases to the science they loved, even to life itself, it may be said +with truth that 'there were giants on the earth in those days,' as far +as aeronautics is in question. It was an age of giants who lived and +dared and died, venturing into uncharted space, knowing nothing of its +dangers, giving, as a man gives to his mistress, without stint and +for the joy of the giving. The science of to-day, compared with the +glimmerings that were in that age of the giants, is a fixed and certain +thing; the problems of to-day are minor problems, for the great major +problem vanished in solution when the Wright Brothers made their first +ascent. In that age of the giants was evolved the flying man, the new +type in human species which found full expression and came to full +development in the days of the war, achieving feats of daring and +endurance which leave the commonplace landsman staggered at thought of +that of which his fellows prove themselves capable. He is a new type, +this flying man, a being of self-forgetfulness; of such was Lilienthal, +of such was Pilcher; of such in later days were Farman, Bleriot, Hamel, +Rolls, and their fellows; great names that will live for as long as man +flies, adventurers equally with those of the spacious days of Elizabeth. +To each of these came the call, and he worked and dared and passed, +having, perhaps, advanced one little step in the long march that has led +toward the perfecting of flight. + +It is not yet twenty years since man first flew, but into that twenty +years have been compressed a century or so of progress, while, in the +two decades that preceded it, was compressed still more. We have only to +recall and recount the work of four men: Lilienthal, Langley, Pilcher, +and Clement Ader to see the immense stride that was made between the +time when Penaud pulled a trigger for the last time and the Wright +Brothers first left the earth. Into those two decades was compressed the +investigation that meant knowledge of the qualities of the air, together +with the development of the one prime mover that rendered flight a +possibility--the internal combustion engine. The coming and progress of +this latter is a thing apart, to be detailed separately; for the present +we are concerned with the evolution of the driven plane, and with it the +evolution of that daring being, the flying man. The two are inseparable, +for the men gave themselves to their art; the story of Lilienthal's life +and death is the story of his work; the story of Pilcher's work is that +of his life and death. + +Considering the flying man as he appeared in the war period, there +entered into his composition a new element--patriotism--which brought +about a modification of the type, or, perhaps, made it appear that +certain men belonged to the type who in reality were commonplace +mortals, animated, under normal conditions, by normal motives, but +driven by the stress of the time to take rank with the last expression +of human energy, the flying type. However that may be, what may be +termed the mathematising of aeronautics has rendered the type itself +evanescent; your pilot of to-day knows his craft, once he is trained, +much in the manner that a driver of a motor-lorry knows his vehicle; +design has been systematised, capabilities have been tabulated; camber, +dihedral angle, aspect ratio, engine power, and plane surface, are +business items of drawing office and machine shop; there is room for +enterprise, for genius, and for skill; once and again there is room for +daring, as in the first Atlantic flight. Yet that again was a thing of +mathematical calculation and petrol storage, allied to a certain stark +courage which may be found even in landsmen. For the ventures into the +unknown, the limit of daring, the work for work's sake, with the almost +certainty that the final reward was death, we must look back to the age +of the giants, the age when flying was not a business, but romance. + + + + +VII. LILIENTHAL AND PILCHER + +There was never a more enthusiastic and consistent student of the +problems of flight than Otto Lilienthal, who was born in 1848 at Anklam, +Pomerania, and even from his early school-days dreamed and planned the +conquest of the air. His practical experiments began when, at the age +of thirteen, he and his brother Gustav made wings consisting of wooden +framework covered with linen, which Otto attached to his arms, and then +ran downhill flapping them. In consequence of possible derision on the +part of other boys, Otto confined these experiments for the most part to +moonlit nights, and gained from them some idea of the resistance offered +by flat surfaces to the air. It was in 1867 that the two brothers +began really practical work, experimenting with wings which, from +their design, indicate some knowledge of Besnier and the history of his +gliding experiments; these wings the brothers fastened to their backs, +moving them with their legs after the fashion of one attempting to swim. +Before they had achieved any real success in gliding the Franco-German +war came as an interruption; both brothers served in this campaign, +resuming their experiments in 1871 at the conclusion of hostilities. + +The experiments made by the brothers previous to the war had convinced +Otto that previous experimenters in gliding flight had failed through +reliance on empirical conclusions or else through incomplete observation +on their own part, mostly of bird flight. From 1871 onward Otto +Lilenthal (Gustav's interest in the problem was not maintained as was +his brother's) made what is probably the most detailed and accurate +series of observations that has ever been made with regard to the +properties of curved wing surfaces. So far as could be done, Lilienthal +tabulated the amount of air resistance offered to a bird's wing, +ascertaining that the curve is necessary to flight, as offering far more +resistance than a flat surface. Cayley, and others, had already stated +this, but to Lilienthal belongs the honour of being first to put the +statement to effective proof--he made over 2,000 gliding flights +between 1891 and the regrettable end of his experiments; his practical +conclusions are still regarded as part of the accepted theory of +students of flight. In 1889 he published a work on the subject of +gliding flight which stands as data for investigators, and, on the +conclusions embodied in this work, he began to build his gliders and +practice what he had preached, turning from experiment with models to +wings that he could use. + +It was in the summer of 1891 that he built his first glider of rods of +peeled willow, over which was stretched strong cotton fabric; with this, +which had a supporting surface of about 100 square feet, Otto Lilienthal +launched himself in the air from a spring board, making glides which, at +first of only a few feet, gradually lengthened. As his experience of +the supporting qualities of the air progressed he gradually altered +his designs until, when Pilcher visited him in the spring of 1895, +he experimented with a glider, roughly made of peeled willow rods and +cotton fabric, having an area of 150 square feet and weighing half a +hundredweight. By this time Lilienthal had moved from his springboard to +a conical artificial hill which he had had thrown up on level ground at +Grosse Lichterfelde, near Berlin. This hill was made with earth taken +from the excavations incurred in constructing a canal, and had a cave +inside in which Lilienthal stored his machines. Pilcher, in his paper +on 'Gliding,' [*] gives an excellent short summary of Lilienthal's +experiments, from which the following extracts are taken:-- + +[*] Aeronautical Classes, No. 5. Royal Aeronautical Society's +publications. + +'At first Lilienthal used to experiment by jumping off a springboard +with a good run. Then he took to practicing on some hills close to +Berlin. In the summer of 1892 he built a flat-roofed hut on the summit +of a hill, from the top of which he used to jump, trying, of course, to +soar as far as possible before landing.... One of the great dangers with +a soaring machine is losing forward speed, inclining the machine too +much down in front, and coming down head first. Lilienthal was the +first to introduce the system of handling a machine in the air merely +by moving his weight about in the machine; he always rested only on his +elbows or on his elbows and shoulders.... + +'In 1892 a canal was being cut, close to where Lilienthal lived, in the +suburbs of Berlin, and with the surplus earth Lilienthal had a special +hill thrown up to fly from. The country round is as flat as the sea, and +there is not a house or tree near it to make the wind unsteady, so +this was an ideal practicing ground; for practicing on natural hills +is generally rendered very difficult by shifty and gusty winds.... This +hill is 50 feet high, and conical. Inside the hill there is a cave for +the machines to be kept in.... When Lilienthal made a good flight he +used to land 300 feet from the centre of the hill, having come down at +an angle of 1 in 6; but his best flights have been at an angle of about +1 in 10. + +'If it is calm, one must run a few steps down the hill, holding the +machine as far back on oneself as possible, when the air will gradually +support one, and one slides off the hill into the air. If there is any +wind, one should face it at starting; to try to start with a side wind +is most unpleasant. It is possible after a great deal of practice to +turn in the air, and fairly quickly. This is accomplished by throwing +one's weight to one side, and thus lowering the machine on that side +towards which one wants to turn. Birds do the same thing--crows and +gulls show it very clearly. Last year Lilienthal chiefly experimented +with double-surfaced machines. These were very much like the old +machines with awnings spread above them. + +'The object of making these double-surfaced machines was to get more +surface without increasing the length and width of the machine. This, +of course, it does, but I personally object to any machine in which +the wing surface is high above the weight. I consider that it makes +the machine very difficult to handle in bad weather, as a puff of wind +striking the surface, high above one, has a great tendency to heel the +machine over. + +'Herr Lilienthal kindly allowed me to sail down his hill in one of these +double-surfaced machines last June. With the great facility afforded by +his conical hill the machine was handy enough; but I am afraid I should +not be able to manage one at all in the squally districts I have had to +practice in over here. + +'Herr Lilienthal came to grief through deserting his old method of +balancing. In order to control his tipping movements more rapidly he +attached a line from his horizontal rudder to his head, so that when he +moved his head forward it would lift the rudder and tip the machine up +in front, and vice versa. He was practicing this on some natural hills +outside Berlin, and he apparently got muddled with the two motions, and, +in trying to regain speed after he had, through a lull in the wind, come +to rest in the air, let the machine get too far down in front, came down +head first and was killed.' + +Then in another passage Pilcher enunciates what is the true value of +such experiments as Lilienthal--and, subsequently, he himself--made: +'The object of experimenting with soaring machines,' he says, 'is to +enable one to have practice in starting and alighting and controlling a +machine in the air. They cannot possibly float horizontally in the +air for any length of time, but to keep going must necessarily lose in +elevation. They are excellent schooling machines, and that is all they +are meant to be, until power, in the shape of an engine working a screw +propeller, or an engine working wings to drive the machine forward, is +added; then a person who is used to soaring down a hill with a simple +soaring machine will be able to fly with comparative safety. One can +best compare them to bicycles having no cranks, but on which one could +learn to balance by coming down an incline.' + +It was in 1895 that Lilienthal passed from experiment with the monoplane +type of glider to the construction of a biplane glider which, according +to his own account, gave better results than his previous machines. +'Six or seven metres velocity of wind,' he says, 'sufficed to enable +the sailing surface of 18 square metres to carry me almost horizontally +against the wind from the top of my hill without any starting jump. If +the wind is stronger I allow myself to be simply lifted from the point +of the hill and to sail slowly towards the wind. The direction of the +flight has, with strong wind, a strong upwards tendency. I often reach +positions in the air which are much higher than my starting point. At +the climax of such a line of flight I sometimes come to a standstill +for some time, so that I am enabled while floating to speak with the +gentlemen who wish to photograph me, regarding the best position for the +photographing.' + +Lilienthal's work did not end with simple gliding, though he did not +live to achieve machine-driven flight. Having, as he considered, gained +sufficient experience with gliders, he constructed a power-driven +machine which weighed altogether about 90 lbs., and this was thoroughly +tested. The extremities of its wings were made to flap, and the driving +power was obtained from a cylinder of compressed carbonic acid gas, +released through a hand-operated valve which, Lilienthal anticipated, +would keep the machine in the air for four minutes. There were certain +minor accidents to the mechanism, which delayed the trial flights, and +on the day that Lilienthal had determined to make his trial he made a +long gliding flight with a view to testing a new form of rudder that--as +Pilcher relates--was worked by movements of his head. His death came +about through the causes that Pilcher states; he fell from a height of +50 feet, breaking his spine, and the next day he died. + +It may be said that Lilienthal accomplished as much as any one of the +great pioneers of flying. As brilliant in his conceptions as da Vinci +had been in his, and as conscientious a worker as Borelli, he laid the +foundations on which Pilcher, Chanute, and Professor Montgomery were +able to build to such good purpose. His book on bird flight, published +in 1889, with the authorship credited both to Otto and his brother +Gustav, is regarded as epoch-making; his gliding experiments are no less +entitled to this description. + +In England Lilienthal's work was carried on by Percy Sinclair Pilcher, +who, born in 1866, completed six years' service in the British Navy +by the time that he was nineteen, and then went through a course of +engineering, subsequently joining Maxim in his experimental work. It was +not until 1895 that he began to build the first of the series of gliders +with which he earned his plane among the pioneers of flight. Probably +the best account of Pilcher's work is that given in the Aeronautical +Classics issued by the Royal Aeronautical Society, from which the +following account of Pilcher's work is mainly abstracted.[*] + +[*] Aeronautical Classes, No. 5. Royal Aeronautical Society +publications. + +The 'Bat,' as Pilcher named his first glider, was a monoplane which he +completed before he paid his visit to Lilienthal in 1895. Concerning +this Pilcher stated that he purposely finished his own machine before +going to see Lilienthal, so as to get the greatest advantage from any +original ideas he might have; he was not able to make any trials with +this machine, however, until after witnessing Lilienthal's experiments +and making several glides in the biplane glider which Lilienthal +constructed. + + +The wings of the 'Bat' formed a pronounced dihedral angle; the tips +being raised 4 feet above the body. The spars forming the entering +edges of the wings crossed each other in the centre and were lashed to +opposite sides of the triangle that served as a mast for the stay-wires +that guyed the wings. The four ribs of each wing, enclosed in pockets +in the fabric, radiated fanwise from the centre, and were each stayed by +three steel piano-wires to the top of the triangular mast, and similarly +to its base. These ribs were bolted down to the triangle at their roots, +and could be easily folded back on to the body when the glider was not +in use. A small fixed vertical surface was carried in the rear. The +framework and ribs were made entirely of Riga pine; the surface fabric +was nainsook. The area of the machine was 150 square feet; its weight +45 lbs.; so that in flight, with Pilcher's weight of 145 lbs. added, it +carried one and a half pounds to the square foot. + +Pilcher's first glides, which he carried out on a grass hill on the +banks of the Clyde near Cardross, gave little result, owing to the +exaggerated dihedral angle of the wings, and the absence of a horizontal +tail. The 'Bat 'was consequently reconstructed with a horizontal tail +plane added to the vertical one, and with the wings lowered so that the +tips were only six inches above the level of the body. The machine now +gave far better results; on the first glide into a head wind Pilcher +rose to a height of twelve feet and remained in the the air for a third +of a minute; in the second attempt a rope was used to tow the glider, +which rose to twenty feet and did not come to earth again until nearly +a minute had passed. With experience Pilcher was able to lengthen his +glide and improve his balance, but the dropped wing tips made landing +difficult, and there were many breakages. + +In consequence of this Pilcher built a second glider which he named +the 'Beetle,' because, as he said, it looked like one. In this the +square-cut wings formed almost a continuous plane, rigidly fixed to the +central body, which consisted of a shaped girder. These wings were built +up of five transverse bamboo spars, with two shaped ribs running from +fore to aft of each wing, and were stayed overhead to a couple of masts. +The tail, consisting of two discs placed crosswise (the horizontal +one alone being movable), was carried high up in the rear. With the +exception of the wing-spars, the whole framework was built of white +pine. The wings in this machine were actually on a higher level than the +operator's head; the centre of gravity was, consequently, very low, a +fact which, according to Pilcher's own account, made the glider very +difficult to handle. Moreover, the weight of the 'Beetle,' 80 lbs., was +considerable; the body had been very solidly built to enable it to carry +the engine which Pilcher was then contemplating; so that the glider +carried some 225 lbs. with its area of 170 square feet--too great a mass +for a single man to handle with comfort. + +It was in the spring of 1896 that Pilcher built his third glider, the +'Gull,' with 300 square feet of area and a weight of 55 lbs. The size of +this machine rendered it unsuitable for experiment in any but very calm +weather, and it incurred such damage when experiments were made in a +breeze that Pilcher found it necessary to build a fourth, which he named +the 'Hawk.' This machine was very soundly built, being constructed of +bamboo, with the exception of the two main transverse beams. The wings +were attached to two vertical masts, 7 feet high, and 8 feet apart, +joined at their summits and their centres by two wooden beams. Each wing +had nine bamboo ribs, radiating from its mast, which was situated at a +distance of 2 feet 6 inches from the forward edge of the wing. Each rib +was rigidly stayed at the top of the mast by three tie-wires, and by a +similar number to the bottom of the mast, by which means the curve of +each wing was maintained uniformly. The tail was formed of a triangular +horizontal surface to which was affixed a triangular vertical surface, +and was carried from the body on a high bamboo mast, which was also +stayed from the masts by means of steel wires, but only on its upper +surface, and it was the snapping of one of these guy wires which caused +the collapse of the tail support and brought about the fatal end of +Pilcher's experiments. In flight, Pilcher's head, shoulders, and the +greater part of his chest projected above the wings. He took up his +position by passing his head and shoulders through the top aperture +formed between the two wings, and resting his forearms on the +longitudinal body members. A very simple form of undercarriage, which +took the weight off the glider on the ground, was fitted, consisting of +two bamboo rods with wheels suspended on steel springs. + +Balance and steering were effected, apart from the high degree of +inherent stability afforded by the tail, as in the case of Lilienthal's +glider, by altering the position of the body. With this machine Pilcher +made some twelve glides at Eynsford in Kent in the summer of 1896, and +as he progressed he increased the length of his glides, and also handled +the machine more easily, both in the air and in landing. He was occupied +with plans for fitting an engine and propeller to the 'Hawk,' but, in +these early days of the internal combustion engine, was unable to +get one light enough for his purpose. There were rumours of an engine +weighing 15 lbs. which gave 1 horse-power, and was reported to be in +existence in America, but it could not be traced. + +In the spring of 1897 Pilcher took up his gliding experiments again, +obtaining what was probably the best of his glides on June 19th, when he +alighted after a perfectly balanced glide of over 250 yards in length, +having crossed a valley at a considerable height. From his various +experiments he concluded that once the machine was launched in the air +an engine of, at most, 3 horse-power would suffice for the maintenance +of horizontal flight, but he had to allow for the additional weight +of the engine and propeller, and taking into account the comparative +inefficiency of the propeller, he planned for an engine of 4 +horse-power. Engine and propeller together were estimated at under 44 +lbs. weight, the engine was to be fitted in front of the operator, and +by means of an overhead shaft was to operate the propeller situated +in rear of the wings. 1898 went by while this engine was under +construction. Then in 1899 Pilcher became interested in Lawrence +Hargrave's soaring kites, with which he carried out experiments during +the summer of 1899. It is believed that he intended to incorporate +a number of these kites in a new machine, a triplane, of which the +fragments remaining are hardly sufficient to reconstitute the complete +glider. This new machine was never given a trial. For on September 30th, +1899, at Stamford Hall, Market Harborough, Pilcher agreed to give a +demonstration of gliding flight, but owing to the unfavourable weather +he decided to postpone the trial of the new machine and to experiment +with the 'Hawk,' which was intended to rise from a level field, towed by +a line passing over a tackle drawn by two horses. At the first trial the +machine rose easily, but the tow-line snapped when it was well clear of +the ground, and the glider descended, weighed down through being sodden +with rain. Pilcher resolved on a second trial, in which the glider again +rose easily to about thirty feet, when one of the guy wires of the tail +broke, and the tail collapsed; the machine fell to the ground, turning +over, and Pilcher was unconscious when he was freed from the wreckage. + +Hopes were entertained of his recovery, but he died on Monday, October +2nd, 1899, aged only thirty-four. His work in the cause of flying +lasted only four years, but in that time his actual accomplishments were +sufficient to place his name beside that of Lilienthal, with whom he +ranks as one of the greatest exponents of gliding flight. + + + + +VIII. AMERICAN GLIDING EXPERIMENTS + +While Pilcher was carrying on Lilienthal's work in England, the great +German had also a follower in America; one Octave Chanute, who, in one +of the statements which he has left on the subject of his experiments +acknowledges forty years' interest in the problem of flight, did more +to develop the glider in America than--with the possible exception +of Montgomery--any other man. Chanute had all the practicality of an +American; he began his work, so far as actual gliding was concerned, +with a full-sized glider of the Lilienthal type, just before Lilienthal +was killed. In a rather rare monograph, entitled Experiments in Flying, +Chanute states that he found the Lilienthal glider hazardous and decided +to test the value of an idea of his own; in this he followed the same +general method, but reversed the principle upon which Lilienthal had +depended for maintaining his equilibrium in the air. Lilienthal had +shifted the weight of his body, under immovable wings, as fast and as +far as the sustaining pressure varied under his surfaces; this shifting +was mainly done by moving the feet, as the actions required were small +except when alighting. Chanute's idea was to have the operator remain +seated in the machine in the air, and to intervene only to steer or to +alight; moving mechanism was provided to adjust the wings automatically +in order to restore balance when necessary. + +Chanute realised that experiments with models were of little use; in +order to be fully instructive, these experiments should be made with +a full-sized machine which carried its operator, for models seldom fly +twice alike in the open air, and no relation can be gained from them of +the divergent air currents which they have experienced. Chanute's idea +was that any flying machine which might be constructed must be able to +operate in a wind; hence the necessity for an operator to report upon +what occurred in flight, and to acquire practical experience of the work +of the human factor in imitation of bird flight. From this point of +view he conducted his own experiments; it must be noted that he was +over sixty years of age when he began, and, being no longer sufficiently +young and active to perform any but short and insignificant glides, the +courage of the man becomes all the more noteworthy; he set to work to +evolve the state required by the problem of stability, and without any +expectation of advancing to the construction of a flying machine which +might be of commercial value. His main idea was the testing of devices +to secure equilibrium; for this purpose he employed assistants to +carry out the practical work, where he himself was unable to supply the +necessary physical energy. + +Together with his assistants he found a suitable place for experiments +among the sandhills on the shore of Lake Michigan, about thirty miles +eastward from Chicago. Here a hill about ninety-five feet high was +selected as a point from which Chanute's gliders could set off; in +practice, it was found that the best observation was to be obtained +from short glides at low speed, and, consequently, a hill which was +only sixty-one feet above the shore of the lake was employed for the +experimental work done by the party. + +In the years 1896 and 1897, with parties of from four to six persons, +five full-sized gliders were tried out, and from these two distinct +types were evolved: of these one was a machine consisting of five tiers +of wings and a steering tail, and the other was of the biplane type; +Chanute believed these to be safer than any other machine previously +evolved, solving, as he states in his monograph, the problem of inherent +equilibrium as fully as this could be done. Unfortunately, very few +photographs were taken of the work in the first year, but one view of a +multiple wing-glider survives, showing the machine in flight. In 1897 a +series of photographs was taken exhibiting the consecutive phases of +a single flight; this series of photographs represents the experience +gained in a total of about one thousand glides, but the point of view +was varied so as to exhibit the consecutive phases of one single flight. + +The experience gained is best told in Chanute's own words. 'The first +thing,' he says, 'which we discovered practically was that the wind +flowing up a hill-side is not a steadily-flowing current like that of a +river. It comes as a rolling mass, full of tumultuous whirls and eddies, +like those issuing from a chimney; and they strike the apparatus with +constantly varying force and direction, sometimes withdrawing support +when most needed. It has long been known, through instrumental +observations, that the wind is constantly changing in force and +direction; but it needed the experience of an operator afloat on a +gliding machine to realise that this all proceeded from cyclonic action; +so that more was learned in this respect in a week than had previously +been acquired by several years of experiments with models. There was a +pair of eagles, living in the top of a dead tree about two miles from +our tent, that came almost daily to show us how such wind effects are +overcome and utilised. The birds swept in circles overhead on +pulseless wings, and rose high up in the air. Occasionally there was +a side-rocking motion, as of a ship rolling at sea, and then the birds +rocked back to an even keel; but although we thought the action was +clearly automatic, and were willing to learn, our teachers were too +far off to show us just how it was done, and we had to experiment for +ourselves.' + +Chanute provided his multiple glider with a seat, but, since each +glide only occupied between eight and twelve seconds, there was little +possibility of the operator seating himself. With the multiple glider a +pair of horizontal bars provided rest for the arms, and beyond these +was a pair of vertical bars which the operator grasped with his hands; +beyond this, the operator was in no way attached to the machine. He +took, at the most, four running steps into the wind, which launched +him in the air, and thereupon he sailed into the wind on a generally +descending course. In the matter of descent Chanute observed the sparrow +and decided to imitate it. 'When the latter,' he says, 'approaches the +street, he throws his body back, tilts his outspread wings nearly square +to the course, and on the cushion of air thus encountered he stops his +speed and drops lightly to the ground. So do all birds. We tried it with +misgivings, but found it perfectly effective. The soft sand was a great +advantage, and even when the experts were racing there was not a single +sprained ankle.' + +With the multiple winged glider some two to three hundred glides were +made without any accident either to the man or to the machine, and the +action was found so effective, the principle so sound, that full plans +were published for the benefit of any experimenters who might wish to +improve on this apparatus. The American Aeronautical Annual for 1897 +contains these plans; Chanute confessed that some movement on the part +of the operator was still required to control the machine, but it was +only a seventh or a sixth part of the movement required for control of +the Lilienthal type. + +Chanute waxed enthusiastic over the possibilities of gliding, concerning +which he remarks that 'There is no more delightful sensation than that +of gliding through the air. All the faculties are on the alert, and +the motion is astonishingly smooth and elastic. The machine responds +instantly to the slightest movement of the operator; the air rushes by +one's ears; the trees and bushes flit away underneath, and the landing +comes all too quickly. Skating, sliding, and bicycling are not to be +compared for a moment to aerial conveyance, in which, perhaps, zest is +added by the spice of danger. For it must be distinctly understood that +there is constant danger in such preliminary experiments. When this +hazard has been eliminated by further evolution, gliding will become a +most popular sport.' + +Later experiments proved that the biplane type of glider gave better +results than the rather cumbrous model consisting of five tiers of +planes. Longer and more numerous glides, to the number of seven to eight +hundred, were obtained, the rate of descent being about one in six. The +longest distance traversed was about 120 yards, but Chanute had dreams +of starting from a hill about 200 feet high, which would have given him +gliding flights of 1,200 feet. He remarked that 'In consequence of +the speed gained by running, the initial stage of the flight is nearly +horizontal, and it is thrilling to see the operator pass from thirty to +forty feet overhead, steering his machine, undulating his course, and +struggling with the wind-gusts which whistle through the guy wires. The +automatic mechanism restores the angle of advance when compromised by +variations of the breeze; but when these come from one side and tilt the +apparatus, the weight has to be shifted to right the machine... these +gusts sometimes raise the machine from ten to twenty feet vertically, +and sometimes they strike the apparatus from above, causing it to +descend suddenly. When sailing near the ground, these vicissitudes can +be counteracted by movements of the body from three to four inches; but +this has to be done instantly, for neither wings nor gravity will wait +on meditation. At a height of three hundred or four hundred feet the +regulating mechanism would probably take care of these wind-gusts, as it +does, in fact, for their minor variations. The speed of the machine +is generally about seventeen miles an hour over the ground, and from +twenty-two to thirty miles an hour relative to the air. Constant effort +was directed to keep down the velocity, which was at times fifty-two +miles an hour. This is the purpose of the starting and gliding against +the wind, which thus furnishes an initial velocity without there being +undue speed at the landing. The highest wind we dared to experiment in +blew at thirty-one miles an hour; when the wind was stronger, we waited +and watched the birds.' + +Chanute details an amusing little incident which occurred in the course +of experiment with the biplane glider. He says that 'We had taken one +of the machines to the top of the hill, and loaded its lower wings with +sand to hold it while we e went to lunch. A gull came strolling inland, +and flapped full-winged to inspect. He swept several circles above the +machine, stretched his neck, gave a squawk and went off. Presently he +returned with eleven other gulls, and they seemed to hold a conclave +about one hundred feet above the big new white bird which they had +discovered on the sand. They circled round after round, and once in a +while there was a series of loud peeps, like those of a rusty gate, as +if in conference, with sudden flutterings, as if a terrifying suggestion +had been made. The bolder birds occasionally swooped downwards to +inspect the monster more closely; they twisted their heads around to +bring first one eye and then the other to bear, and then they rose +again. After some seven or eight minutes of this performance, they +evidently concluded either that the stranger was too formidable to +tackle, if alive, or that he was not good to eat, if dead, and they flew +off to resume fishing, for the weak point about a bird is his stomach.' + +The gliders were found so stable, more especially the biplane form, that +in the end Chanute permitted amateurs to make trials under guidance, +and throughout the whole series of experiments not a single accident +occurred. Chanute came to the conclusion that any young, quick, and +handy man could master a gliding machine almost as soon as he could get +the hang of a bicycle, although the penalty for any mistake would be +much more severe. + +At the conclusion of his experiments he decided that neither the +multiple plane nor the biplane type of glider was sufficiently perfected +for the application of motive power. In spite of the amount of automatic +stability that he had obtained he considered that there was yet more to +be done, and he therefore advised that every possible method of securing +stability and safety should be tested, first with models, and then with +full-sized machines; designers, he said, should make a point of practice +in order to make sure of the action, to proportion and adjust the parts +of their machine, and to eliminate hidden defects. Experimental +flight, he suggested, should be tried over water, in order to break any +accidental fall; when a series of experiments had proved the stability +of a glider, it would then be time to apply motive power. He admitted +that such a process would be both costly and slow, but, he said, that +'it greatly diminished the chance of those accidents which bring a whole +line of investigation into contempt.' He saw the flying machine as what +it has, in fact, been; a child of evolution, carried on step by step +by one investigator after another, through the stages of doubt and +perplexity which lie behind the realm of possibility, beyond which is +the present day stage of actual performance and promise of ultimate +success and triumph over the earlier, more cumbrous, and slower forms of +the transport that we know. + +Chanute's monograph, from which the foregoing notes have been comprised, +was written soon after the conclusion of his series of experiments. He +does not appear to have gone in for further practical work, but to +have studied the subject from a theoretical view-point and with great +attention to the work done by others. In a paper contributed in 1900 +to the American Independent, he remarks that 'Flying machines promise +better results as to speed, but yet will be of limited commercial +application. They may carry mails and reach other inaccessible places, +but they cannot compete with railroads as carriers of passengers or +freight. They will not fill the heavens with commerce, abolish custom +houses, or revolutionise the world, for they will be expensive for +the loads which they can carry, and subject to too many weather +contingencies. Success is, however, probable. Each experimenter has +added something to previous knowledge which his successors can avail of. +It now seems likely that two forms of flying machines, a sporting type +and an exploration type, will be gradually evolved within one or two +generations, but the evolution will be costly and slow, and must be +carried on by well-equipped and thoroughly informed scientific men; for +the casual inventor, who relies upon one or two happy inspirations, will +have no chance of success whatever.' + +Follows Professor John J. Montgomery, who, in the true American spirit, +describes his own experiments so well that nobody can possibly do it +better. His account of his work was given first of all in the American +Journal, Aeronautics, in January, 1909, and thence transcribed in the +English paper of the same name in May, 1910, and that account is here +copied word for word. It may, however, be noted first that as far back +as 1860, when Montgomery was only a boy, he was attracted to the study +of aeronautical problems, and in 1883 he built his first machine, +which was of the flapping-wing ornithopter type, and which showed its +designer, with only one experiment, that he must design some other +form of machine if he wished to attain to a successful flight. +Chanute details how, in 1884 and 1885 Montgomery built three gliders, +demonstrating the value of curved surfaces. With the first of these +gliders Montgomery copied the wing of a seagull; with the second he +proved that a flat surface was virtually useless, and with the third +he pivoted his wings as in the Antoinette type of power-propelled +aeroplane, proving to his own satisfaction that success lay in this +direction. His own account of the gliding flights carried out under his +direction is here set forth, being the best description of his work that +can be obtained:-- + +'When I commenced practical demonstration in my work with aeroplanes +I had before me three points; first, equilibrium; second, complete +control; and third, long continued or soaring flight. In starting I +constructed and tested three sets of models, each in advance of the +other in regard to the continuance of their soaring powers, but all +equally perfect as to equilibrium and control. These models were tested +by dropping them from a cable stretched between two mountain tops, with +various loads, adjustments and positions. And it made no difference +whether the models were dropped upside down or any other conceivable +position, they always found their equilibrium immediately and glided +safely to earth. + +'Then I constructed a large machine patterned after the first model, and +with the assistance of three cowboy friends personally made a number of +flights in the steep mountains near San Juan (a hundred miles distant). +In making these flights I simply took the aeroplane and made a running +jump. These tests were discontinued after I put my foot into a squirrel +hole in landing and hurt my leg. + +'The following year I commenced the work on a larger scale, by engaging +aeronauts to ride my aeroplane dropped from balloons. During this work I +used five hot-air balloons and one gas balloon, five or six aeroplanes, +three riders--Maloney, Wilkie, and Defolco--and had sixteen applicants +on my list, and had a training station to prepare any when I needed +them. + +'Exhibitions were given in Santa Cruz, San Jose, Santa Clara, Oaklands, +and Sacramento. The flights that were made, instead of being haphazard +affairs, were in the order of safety and development. In the first +flight of an aeronaut the aeroplane was so arranged that the rider had +little liberty of action, consequently he could make only a limited +flight. In some of the first flights, the aeroplane did little more than +settle in the air. But as the rider gained experience in each successive +flight I changed the adjustments, giving him more liberty of action, so +he could obtain longer flights and more varied movements in the flights. +But in none of the flights did I have the adjustments so that the riders +had full liberty, as I did not consider that they had the requisite +knowledge and experience necessary for their safety; and hence, none +of my aeroplanes were launched so arranged that the rider could make +adjustments necessary for a full flight. + +'This line of action caused a good deal of trouble with aeronauts or +riders, who had unbounded confidence and wanted to make long flights +after the first few trials; but I found it necessary, as they seemed +slow in comprehending the important elements and were willing to +take risks. To give them the full knowledge in these matters I was +formulating plans for a large starting station on the Mount Hamilton +Range from which I could launch an aeroplane capable of carrying two, +one of my aeronauts and myself, so I could teach him by demonstration. +But the disasters consequent on the great earthquake completely stopped +all my work on these lines. The flights that were given were only the +first of the series with aeroplanes patterned after the first model. +There were no aeroplanes constructed according to the two other models, +as I had not given the full demonstration of the workings of the first, +though some remarkable and startling work was done. On one occasion +Maloney, in trying to make a very short turn in rapid flight, pressed +very hard on the stirrup which gives a screw-shape to the wings, and +made a side somersault. The course of the machine was very much like one +turn of a corkscrew. After this movement the machine continued on its +regular course. And afterwards Wilkie, not to be outdone by Maloney, +told his friends he would do the same, and in a subsequent flight made +two side somersaults, one in one direction and the other in an opposite, +then made a deep dive and a long glide, and, when about three hundred +feet in the air, brought the aeroplane to a sudden stop and settled to +the earth. After these antics, I decreased the extent of the possible +change in the form of wing-surface, so as to allow only straight sailing +or only long curves in turning. + +'During my work I had a few carping critics that I silenced by this +standing offer: If they would deposit a thousand dollars I would cover +it on this proposition. I would fasten a 150 pound sack of sand in the +rider's seat, make the necessary adjustments, and send up an aeroplane +upside down with a balloon, the aeroplane to be liberated by a time +fuse. If the aeroplane did not immediately right itself, make a flight, +and come safely to the ground, the money was theirs. + +'Now a word in regard to the fatal accident. The circumstances are +these: The ascension was given to entertain a military company in which +were many of Maloney's friends, and he had told them he would give the +most sensational flight they ever heard of. As the balloon was rising +with the aeroplane, a guy rope dropping switched around the right wing +and broke the tower that braced the two rear wings and which also gave +control over the tail. We shouted Maloney that the machine was broken, +but he probably did not hear us, as he was at the same time saying, +"Hurrah for Montgomery's airship," and as the break was behind him, he +may not have detected it. Now did he know of the breakage or not, and if +he knew of it did he take a risk so as not to disappoint his friends? +At all events, when the machine started on its flight the rear wings +commenced to flap (thus indicating they were loose), the machine turned +on its back, and settled a little faster than a parachute. When we +reached Maloney he was unconscious and lived only thirty minutes. The +only mark of any kind on him was a scratch from a wire on the side of +his neck. The six attending physicians were puzzled at the cause of his +death. This is remarkable for a vertical descent of over 2,000 feet.' + +The flights were brought to an end by the San Francisco earthquake in +April, 1906, which, Montgomery states, 'Wrought such a disaster that I +had to turn my attention to other subjects and let the aeroplane rest +for a time.' Montgomery resumed experiments in 1911 in California, and +in October of that year an accident brought his work to an end. The +report in the American Aeronautics says that 'a little whirlwind caught +the machine and dashed it head on to the ground; Professor Montgomery +landed on his head and right hip. He did not believe himself seriously +hurt, and talked with his year-old bride in the tent. He complained of +pains in his back, and continued to grow worse until he died.' + + + + +IX. NOT PROVEN + +The early history of flying, like that of most sciences, is replete +with tragedies; in addition to these it contains one mystery concerning +Clement Ader, who was well known among European pioneers in the +development of the telephone, and first turned his attention to the +problems of mechanical flight in 1872. At the outset he favoured the +ornithopter principle, constructing a machine in the form of a bird with +a wing-spread of twenty-six feet; this, according to Ader's conception, +was to fly through the efforts of the operator. The result of such +an attempt was past question and naturally the machine never left the +ground. + +A pause of nineteen years ensued, and then in 1886 Ader turned his mind +to the development of the aeroplane, constructing a machine of bat-like +form with a wingspread of about forty-six feet, a weight of eleven +hundred pounds, and a steam-power plant of between twenty and thirty +horse-power driving a four-bladed tractor screw. On October 9th, 1890, +the first trials of this machine were made, and it was alleged to have +flown a distance of one hundred and sixty-four feet. Whatever truth +there may be in the allegation, the machine was wrecked through +deficient equilibrium at the end of the trial. Ader repeated the +construction, and on October 14th, 1897, tried out his third machine +at the military establishment at Satory in the presence of the French +military authorities, on a circular track specially prepared for the +experiment. Ader and his friends alleged that a flight of nearly a +thousand feet was made; again the machine was wrecked at the end of the +trial, and there Ader's practical work may be said to have ended, since +no more funds were forthcoming for the subsidy of experiments. + +There is the bald narrative, but it is worthy of some amplification. If +Ader actually did what he claimed, then the position which the Wright +Brothers hold as first to navigate the air in a power-driven plane is +nullified. Although at this time of writing it is not a quarter of a +century since Ader's experiment in the presence of witnesses competent +to judge on his accomplishment, there is no proof either way, and +whether he was or was not the first man to fly remains a mystery in the +story of the conquest of the air. + +The full story of Ader's work reveals a persistence and determination to +solve the problem that faced him which was equal to that of Lilienthal. +He began by penetrating into the interior of Algeria after having +disguised himself as an Arab, and there he spent some months in studying +flight as practiced by the vultures of the district. Returning to France +in 1886 he began to construct the 'Eole,' modelling it, not on the +vulture, but in the shape of a bat. Like the Lilienthal and Pilcher +gliders this machine was fitted with wings which could be folded; the +first flight made, as already noted, on October 9th, 1890, took place +in the grounds of the chateau d'Amainvilliers, near Bretz; two +fellow-enthusiasts named Espinosa and Vallier stated that a flight +was actually made; no statement in the history of aeronautics has been +subject of so much question, and the claim remains unproved. + +It was in September of 1891 that Ader, by permission of the Minister of +War, moved the 'Eole' to the military establishment at Satory for the +purpose of further trial. By this time, whether he had flown or not, +his nineteen years of work in connection with the problems attendant on +mechanical flight had attracted so much attention that henceforth +his work was subject to the approval of the military authorities, for +already it was recognised that an efficient flying machine would confer +an inestimable advantage on the power that possessed it in the event +of war. At Satory the 'Eole' was alleged to have made a flight of 109 +yards, or, according to another account, 164 feet, as stated above, in +the trial in which the machine wrecked itself through colliding with +some carts which had been placed near the track--the root cause of this +accident, however, was given as deficient equilibrium. + +Whatever the sceptics may say, there is reason for belief in the +accomplishment of actual flight by Ader with his first machine in the +fact that, after the inevitable official delay of some months, the +French War Ministry granted funds for further experiment. Ader named +his second machine, which he began to build in May, 1892, the 'Avion,' +and--an honour which he well deserve--that name remains in French +aeronautics as descriptive of the power-driven aeroplane up to this day. + +This second machine, however, was not a success, and it was not until +1897 that the second 'Avion,' which was the third power-driven aeroplane +of Ader's construction, was ready for trial. This was fitted with +two steam motors of twenty horse-power each, driving two four-bladed +propellers; the wings warped automatically: that is to say, if it +were necessary to raise the trailing edge of one wing on the turn, +the trailing edge of the opposite wing was also lowered by the same +movement; an under-carriage was also fitted, the machine running on +three small wheels, and levers controlled by the feet of the aviator +actuated the movement of the tail planes. + +On October the 12th, 1897, the first trials of this 'Avion' were made +in the presence of General Mensier, who admitted that the machine made +several hops above the ground, but did not consider the performance as +one of actual flight. The result was so encouraging, in spite of the +partial failure, that, two days later, General Mensier, accompanied by +General Grillon, a certain Lieutenant Binet, and two civilians named +respectively Sarrau and Leaute, attended for the purpose of giving the +machine an official trial, over which the great controversy regarding +Ader's success or otherwise may be said to have arisen. + +We will take first Ader's own statement as set out in a very competent +account of his work published in Paris in 1910. Here are Ader's own +words: 'After some turns of the propellers, and after travelling a few +metres, we started off at a lively pace; the pressure-gauge registered +about seven atmospheres; almost immediately the vibrations of the rear +wheel ceased; a little later we only experienced those of the front +wheels at intervals. 'Unhappily, the wind became suddenly strong, and +we had some difficulty in keeping the "Avion" on the white line. We +increased the pressure to between eight and nine atmospheres, and +immediately the speed increased considerably, and the vibrations of +the wheels were no longer sensible; we were at that moment at the point +marked G in the sketch; the "Avion" then found itself freely supported +by its wings; under the impulse of the wind it continually tended to go +outside the (prepared) area to the right, in spite of the action of +the rudder. On reaching the point V it found itself in a very critical +position; the wind blew strongly and across the direction of the white +line which it ought to follow; the machine then, although still going +forward, drifted quickly out of the area; we immediately put over the +rudder to the left as far as it would go; at the same time increasing +the pressure still more, in order to try to regain the course. The +"Avion" obeyed, recovered a little, and remained for some seconds headed +towards its intended course, but it could not struggle against the wind; +instead of going back, on the contrary it drifted farther and farther +away. And ill-luck had it that the drift took the direction towards +part of the School of Musketry, which was guarded by posts and +barriers. Frightened at the prospect of breaking ourselves against these +obstacles, surprised at seeing the earth getting farther away from under +the "Avion," and very much impressed by seeing it rushing sideways at +a sickening speed, instinctively we stopped everything. What passed +through our thoughts at this moment which threatened a tragic turn would +be difficult to set down. All at once came a great shock, splintering, a +heavy concussion: we had landed.' + +Thus speaks the inventor; the cold official mind gives out a different +account, crediting the 'Avion' with merely a few hops, and to-day, among +those who consider the problem at all, there is a little group which +persists in asserting that to Ader belongs the credit of the first +power-driven flight, while a larger group is equally persistent in +stating that, save for a few ineffectual hops, all three wheels of the +machine never left the ground. It is past question that the 'Avion' was +capable of power-driven flight; whether it achieved it or no remains an +unsettled problem. + +Ader's work is negative proof of the value of such experiments as +Lilienthal, Pilcher, Chanute, and Montgomery conducted; these four set +to work to master the eccentricities of the air before attempting to +use it as a supporting medium for continuous flight under power; Ader +attacked the problem from the other end; like many other experimenters +he regarded the air as a stable fluid capable of giving such support to +his machine as still water might give to a fish, and he reckoned that he +had only to produce the machine in order to achieve flight. The wrecked +'Avion' and the refusal of the French War Ministry to grant any more +funds for further experiment are sufficient evidence of the need for +working along the lines taken by the pioneers of gliding rather than on +those which Ader himself adopted. + +Let it not be thought that in this comment there is any desire to +derogate from the position which Ader should occupy in any study of +the pioneers of aeronautical enterprise. If he failed, he failed +magnificently, and if he succeeded, then the student of aeronautics does +him an injustice and confers on the Brothers Wright an honour which, +in spite of the value of their work, they do not deserve. There was +one earlier than Ader, Alphonse Penaud, who, in the face of a lesser +disappointment than that which Ader must have felt in gazing on the +wreckage of his machine, committed suicide; Ader himself, rendered +unable to do more, remained content with his achievement, and with the +knowledge that he had played a good part in the long search which must +eventually end in triumph. Whatever the world might say, he himself was +certain that he had achieved flight. This, for him, was perforce enough. + +Before turning to consideration of the work accomplished by the Brothers +Wright, and their proved conquest of the air, it is necessary first to +sketch as briefly as may be the experimental work of Sir (then Mr) Hiram +Maxim, who, in his book, Artificial and Natural Flight, has given +a fairly complete account of his various experiments. He began by +experimenting with models, with screw-propelled planes so attached to a +horizontal movable arm that when the screw was set in motion the plane +described a circle round a central point, and, eventually, he built a +giant aeroplane having a total supporting area of 1,500 square feet, +and a wing-span of fifty feet. It has been thought advisable to give +a fairly full description of the power plant used to the propulsion +of this machine in the section devoted to engine development. The +aeroplane, as Maxim describes it, had five long and narrow planes +projecting from each side, and a main or central plane of pterygoid +aspect. A fore and aft rudder was provided, and had all the auxiliary +planes been put in position for experimental work a total lifting +surface of 6,000 square feet could have been obtained. Maxim, however, +did not use more than 4,000 square feet of lifting surface even in his +later experiments; with this he judged the machine capable of lifting +slightly under 8,000 lbs. weight, made up of 600 lbs. water in the +boiler and tank, a crew of three men, a supply of naphtha fuel, and the +weight of the machine itself. + +Maxim's intention was, before attempting free flight, to get as much +data as possible regarding the conditions under which flight must be +obtained, by what is known in these days as 'taxi-ing'--that is, running +the propellers at sufficient speed to drive the machine along the ground +without actually mounting into the air. He knew that he had an immense +lifting surface and a tremendous amount of power in his engine even when +the total weight of the experimental plant was taken into consideration, +and thus he set about to devise some means of keeping the machine on the +nine foot gauge rail track which had been constructed for the trials. At +the outset he had a set of very heavy cast-iron wheels made on which to +mount the machine, the total weight of wheels, axles, and connections +being about one and a half tons. These were so constructed that the +light flanged wheels which supported the machine on the steel rails +could be lifted six inches above the track, still leaving the heavy +wheels on the rails for guidance of the machine. 'This arrangement,' +Maxim states, 'was tried on several occasions, the machine being run +fast enough to lift the forward end off the track. However, I found +considerable difficulty in starting and stopping quickly on account of +the great weight, and the amount of energy necessary to set such heavy +wheels spinning at a high velocity. The last experiment with these +wheels was made when a head wind was blowing at the rate of about ten +miles an hour. It was rather unsteady, and when the machine was running +at its greatest velocity, a sudden gust lifted not only the front +end, but also the heavy front wheels completely off the track, and the +machine falling on soft ground was soon blown over by the wind.' + +Consequently, a safety track was provided, consisting of squared pine +logs, three inches by nine inches, placed about two feet above the steel +way and having a thirty-foot gauge. Four extra wheels were fitted to the +machine on outriggers and so adjusted that, if the machine should +lift one inch clear of the steel rails, the wheels at the ends of the +outriggers would engage the under side of the pine trackway. + +The first fully loaded run was made in a dead calm with 150 lbs. steam +pressure to the square inch, and there was no sign of the wheels leaving +the steel track. On a second run, with 230 lbs. steam pressure the +machine seemed to alternate between adherence to the lower and upper +tracks, as many as three of the outrigger wheels engaging at the same +time, and the weight on the steel rails being reduced practically to +nothing. In preparation for a third run, in which it was intended to use +full power, a dynamometer was attached to the machine and the engines +were started at 200 lbs. pressure, which was gradually increased to 310 +lbs per square inch. The incline of the track, added to the reading of +the dynamometer, showed a total screw thrust of 2,164 lbs. After the +dynamometer test had been completed, and everything had been made ready +for trial in motion, careful observers were stationed on each side of +the track, and the order was given to release the machine. What follows +is best told in Maxim's own words:-- + +'The enormous screw-thrust started the engine so quickly that it nearly +threw the engineers off their feet, and the machine bounded over the +track at a great rate. Upon noticing a slight diminution in the +steam pressure, I turned on more gas, when almost instantly the steam +commenced to blow a steady blast from the small safety valve, showing +that the pressure was at least 320 lbs. in the pipes supplying the +engines with steam. Before starting on this run, the wheels that were +to engage the upper track were painted, and it was the duty of one of +my assistants to observe these wheels during the run, while another +assistant watched the pressure gauges and dynagraphs. The first part of +the track was up a slight incline, but the machine was lifted clear +of the lower rails and all of the top wheels were fully engaged on the +upper track when about 600 feet had been covered. The speed rapidly +increased, and when 900 feet had been covered, one of the rear axle +trees, which were of two-inch steel tubing, doubled up and set the rear +end of the machine completely free. The pencils ran completely across +the cylinders of the dynagraphs and caught on the underneath end. The +rear end of the machine being set free, raised considerably above the +track and swayed. At about 1,000 feet, the left forward wheel also got +clear of the upper track, and shortly afterwards the right forward wheel +tore up about 100 feet of the upper track. Steam was at once shut off +and the machine sank directly to the earth, embedding the wheels in the +soft turf without leaving any other marks, showing most conclusively +that the machine was completely suspended in the air before it settled +to the earth. In this accident, one of the pine timbers forming the +upper track went completely through the lower framework of the machine +and broke a number of the tubes, but no damage was done to the machinery +except a slight injury to one of the screws.' + +It is a pity that the multifarious directions in which Maxim turned his +energies did not include further development of the aeroplane, for it +seems fairly certain that he was as near solution of the problem as Ader +himself, and, but for the holding-down outer track, which was really the +cause of his accident, his machine would certainly have achieved free +flight, though whether it would have risen, flown and alighted, without +accident, is matter for conjecture. + +The difference between experiments with models and with full-sized +machines is emphasised by Maxim's statement to the effect that with +a small apparatus for ascertaining the power required for artificial +flight, an angle of incidence of one in fourteen was most advantageous, +while with a large machine he found it best to increase his angle to one +in eight in order to get the maximum lifting effect on a short run at a +moderate speed. He computed the total lifting effect in the experiments +which led to the accident as not less than 10,000 lbs., in which is +proof that only his rail system prevented free flight. + + + + +X. SAMUEL PIERPOINT LANGLEY + +Langley was an old man when he began the study of aeronautics, or, as +he himself might have expressed it, the study of aerodromics, since he +persisted in calling the series of machines he built 'Aerodromes,' a +word now used only to denote areas devoted to use as landing spaces for +flying machines; the Wright Brothers, on the other hand, had the great +gift of youth to aid them in their work. Even so it was a great race +between Langley, aided by Charles Manly, and Wilbur and Orville Wright, +and only the persistent ill-luck which dogged Langley from the start to +the finish of his experiments gave victory to his rivals. It has been +proved conclusively in these later years of accomplished flight that the +machine which Langley launched on the Potomac River in October of 1903 +was fully capable of sustained flight, and only the accidents incurred +in launching prevented its pilot from being the first man to navigate +the air successfully in a power-driven machine. + +The best account of Langley's work is that diffused throughout a weighty +tome issued by the Smithsonian Institution, entitled the Langley Memoir +on Mechanical Flight, of which about one-third was written by Langley +himself, the remainder being compiled by Charles M. Manly, the engineer +responsible for the construction of the first radial aero-engine, and +chief assistant to Langley in his experiments. To give a twentieth +of the contents of this volume in the present short account of the +development of mechanical flight would far exceed the amount of space +that can be devoted even to so eminent a man in aeronautics as S. +P. Langley, who, apart from his achievement in the construction of a +power-driven aeroplane really capable of flight, was a scientist of no +mean order, and who brought to the study of aeronautics the skill of the +trained investigator allied to the inventive resource of the genius. + +That genius exemplified the antique saw regarding the infinite capacity +for taking pains, for the Langley Memoir shows that as early as 1891 +Langley had completed a set of experiments, lasting through years, +which proved it possible to construct machines giving such a velocity +to inclined surfaces that bodies indefinitely heavier than air could +be sustained upon it and propelled through it at high speed. For full +account (very full) of these experiments, and of a later series leading +up to the construction of a series of 'model aerodromes' capable of +flight under power, it is necessary to turn to the bulky memoir of +Smithsonian origin. + +The account of these experiments as given by Langley himself reveals +the humility of the true investigator. Concerning them, Langley remarks +that, 'Everything here has been done with a view to putting a trial +aerodrome successfully in flight within a few years, and thus giving an +early demonstration of the only kind which is conclusive in the eyes of +the scientific man, as well as of the general public--a demonstration +that mechanical flight is possible--by actually flying. All that has +been done has been with an eye principally to this immediate result, +and all the experiments given in this book are to be considered only as +approximations to exact truth. All were made with a view, not to some +remote future, but to an arrival within the compass of a few years at +some result in actual flight that could not be gainsaid or mistaken.' + +With a series of over thirty rubber-driven models Langley demonstrated +the practicability of opposing curved surfaces to the resistance of the +air in such a way as to achieve flight, in the early nineties of last +century; he then set about finding the motive power which should permit +of the construction of larger machines, up to man-carrying size. The +internal combustion engine was then an unknown quantity, and he had to +turn to steam, finally, as the propulsive energy for his power plant. +The chief problem which faced him was that of the relative weight and +power of his engine; he harked back to the Stringfellow engine of 1868, +which in 1889 came into the possession of the Smithsonian Institution +as a historical curiosity. Rightly or wrongly Langley concluded on +examination that this engine never had developed and never could +develop more than a tenth of the power attributed to it; consequently +he abandoned the idea of copying the Stringfellow design and set about +making his own engine. + +How he overcame the various difficulties that faced him and constructed +a steam-engine capable of the task allotted to it forms a story in +itself, too long for recital here. His first power-driven aerodrome +of model size was begun in November of 1891, the scale of construction +being decided with the idea that it should be large enough to carry an +automatic steering apparatus which would render the machine capable of +maintaining a long and steady flight. The actual weight of the first +model far exceeded the theoretical estimate, and Langley found that a +constant increase of weight under the exigencies of construction was a +feature which could never be altogether eliminated. The machine was made +principally of steel, the sustaining surfaces being composed of silk +stretched from a steel tube with wooden attachments. The first engines +were the oscillating type, but were found deficient in power. This led +to the construction of single-acting inverted oscillating engines with +high and low pressure cylinders, and with admission and exhaust ports +to avoid the complication and weight of eccentric and valves. Boiler and +furnace had to be specially designed; an analysis of sustaining surfaces +and the settlement of equilibrium while in flight had to be overcome, +and then it was possible to set about the construction of the series of +model aerodromes and make test of their 'lift.' + +By the time Langley had advanced sufficiently far to consider it +possible to conduct experiments in the open air, even with these models, +he had got to his fifth aerodrome, and to the year 1894. Certain tests +resulted in failure, which in turn resulted in further modifications of +design, mainly of the engines. By February of 1895 Langley reported +that under favourable conditions a lift of nearly sixty per cent of +the flying weight was secured, but although this was much more than +was required for flight, it was decided to postpone trials until two +machines were ready for the test. May, 1896, came before actual trials +were made, when one machine proved successful and another, a later +design, failed. The difficulty with these models was that of securing +a correct angle for launching; Langley records how, on launching one +machine, it rose so rapidly that it attained an angle of sixty degrees +and then did a tail slide into the water with its engines working at +full speed, after advancing nearly forty feet and remaining in the +air for about three seconds. Here, Langley found that he had to obtain +greater rigidity in his wings, owing to the distortion of the form of +wing under pressure, and how he overcame this difficulty constitutes yet +another story too long for the telling here. + +Field trials were first attempted in 1893, and Langley blamed his +launching apparatus for their total failure. There was a brief, but at +the same time practical, success in model flight in 1894, extending +to between six and seven seconds, but this only proved the need for +strengthening of the wing. In 1895 there was practically no advance +toward the solution of the problem, but the flights of May 6th and +November 28th, 1896, were notably successful. A diagram given in +Langley's memoir shows the track covered by the aerodrome on these two +flights; in the first of them the machine made three complete circles, +covering a distance of 3,200 feet; in the second, that of November 28th, +the distance covered was 4,200 feet, or about three-quarters of a mile, +at a speed of about thirty miles an hour. + +These achievements meant a good deal; they proved mechanically propelled +flight possible. The difference between them and such experiments as +were conducted by Clement Ader, Maxim, and others, lay principally in +the fact that these latter either did or did not succeed in rising into +the air once, and then, either willingly or by compulsion, gave up +the quest, while Langley repeated his experiments and thus attained to +actual proof of the possibilities of flight. Like these others, however, +he decided in 1896 that he would not undertake the construction of a +large man-carrying machine. In addition to a multitude of actual duties, +which left him practically no time available for original research, he +had as an adverse factor fully ten years of disheartening difficulties +in connection with his model machines. It was President McKinley who, by +requesting Langley to undertake the construction and test of a machine +which might finally lead to the development of a flying machine +capable of being used in warfare, egged him on to his final experiment. +Langley's acceptance of the offer to construct such a machine is +contained in a letter addressed from the Smithsonian Institution on +December 12th, 1898, to the Board of Ordnance and Fortification of the +United States War Department; this letter is of such interest as to +render it worthy of reproduction:-- + +'Gentlemen,--In response to your invitation I repeat what I had the +honour to say to the Board--that I am willing, with the consent of the +Regents of this Institution, to undertake for the Government the further +investigation of the subject of the construction of a flying machine +on a scale capable of carrying a man, the investigation to include the +construction, development and test of such a machine under conditions +left as far as practicable in my discretion, it being understood that my +services are given to the Government in such time as may not be occupied +by the business of the Institution, and without charge. + +'I have reason to believe that the cost of the construction will come +within the sum of $50,000.00, and that not more than one-half of that +will be called for in the coming year. + +'I entirely agree with what I understand to be the wish of the Board +that privacy be observed with regard to the work, and only when it +reaches a successful completion shall I wish to make public the fact of +its success. + +'I attach to this a memorandum of my understanding of some points of +detail in order to be sure that it is also the understanding of the +Board, and I am, gentlemen, with much respect, your obedient servant, S. +P. Langley.' + +One of the chief problems in connection with the construction of a +full-sized apparatus was that of the construction of an engine, for it +was realised from the first that a steam power plant for a full-sized +machine could only be constructed in such a way as to make it a constant +menace to the machine which it was to propel. By this time (1898) the +internal combustion engine had so far advanced as to convince Langley +that it formed the best power plant available. A contract was made for +the delivery of a twelve horse-power engine to weigh not more than a +hundred pounds, but this contract was never completed, and it fell to +Charles M. Manly to design the five-cylinder radial engine, of which a +brief account is included in the section of this work devoted to aero +engines, as the power plant for the Langley machine. + +The history of the years 1899 to 1903 in the Langley series of +experiments contains a multitude of detail far beyond the scope of +this present study, and of interest mainly to the designer. There were +frames, engines, and propellers, to be considered, worked out, and +constructed. We are concerned here mainly with the completed machine and +its trials. Of these latter it must be remarked that the only two actual +field trials which took place resulted in accidents due to the failure +of the launching apparatus, and not due to any inherent defect in the +machine. It was intended that these two trials should be the first of +a series, but the unfortunate accidents, and the fact that no further +funds were forthcoming for continuance of experiments, prevented +Langley's success, which, had he been free to go through as he intended +with his work, would have been certain. + +The best brief description of the Langley aerodrome in its final form, +and of the two attempted trials, is contained in the official report of +Major M. M. Macomb of the United States Artillery Corps, which report is +here given in full:-- + + REPORT + +Experiments with working models which were concluded August 8 last +having proved the principles and calculations on which the design of the +Langley aerodrome was based to be correct, the next step was to apply +these principles to the construction of a machine of sufficient size +and power to permit the carrying of a man, who could control the motive +power and guide its flight, thus pointing the way to attaining the final +goal of producing a machine capable of such extensive and precise aerial +flight, under normal atmospheric conditions, as to prove of military or +commercial utility. + +Mr C. M. Manly, working under Professor Langley, had, by the summer +of 1903, succeeded in completing an engine-driven machine which under +favourable atmospheric conditions was expected to carry a man for any +time up to half an hour, and to be capable of having its flight directed +and controlled by him. + +The supporting surface of the wings was ample, and experiment showed the +engine capable of supplying more than the necessary motive power. + +Owing to the necessity of lightness, the weight of the various elements +had to be kept at a minimum, and the factor of safety in construction +was therefore exceedingly small, so that the machine as a whole was +delicate and frail and incapable of sustaining any unusual strain. This +defect was to be corrected in later models by utilising data gathered in +future experiments under varied conditions. + +One of the most remarkable results attained was the production of a +gasoline engine furnishing over fifty continuous horse-power for a +weight of 120 lbs. + +The aerodrome, as completed and prepared for test, is briefly described +by Professor Langley as 'built of steel, weighing complete about +730 lbs., supported by 1,040 feet of sustaining surface, having two +propellers driven by a gas engine developing continuously over fifty +brake horse-power.' + +The appearance of the machine prepared for flight was exceedingly light +and graceful, giving an impression to all observers of being capable of +successful flight. + +On October 7 last everything was in readiness, and I witnessed the +attempted trial on that day at Widewater, Va. On the Potomac. The engine +worked well and the machine was launched at about 12.15 p.m. The trial +was unsuccessful because the front guy-post caught in its support on the +launching car and was not released in time to give free flight, as was +intended, but, on the contrary, caused the front of the machine to be +dragged downward, bending the guy-post and making the machine plunge +into the water about fifty yards in front of the house-boat. The machine +was subsequently recovered and brought back to the house-boat. The +engine was uninjured and the frame only slightly damaged, but the four +wings and rudder were practically destroyed by the first plunge and +subsequent towing back to the house-boat. + +This accident necessitated the removal of the house-boat to Washington +for the more convenient repair of damages. + +On December 8 last, between 4 and 5 p.m., another attempt at a trial was +made, this time at the junction of the Anacostia with the Potomac, just +below Washington Barracks. + +On this occasion General Randolph and myself represented the Board of +Ordnance and Fortification. The launching car was released at 4.45 p.m. +being pointed up the Anacostia towards the Navy Yard. My position was +on the tug Bartholdi, about 150 feet from and at right angles to +the direction of proposed flight. The car was set in motion and the +propellers revolved rapidly, the engine working perfectly, but there was +something wrong with the launching. The rear guy-post seemed to drag, +bringing the rudder down on the launching ways, and a crashing, rending +sound, followed by the collapse of the rear wings, showed that the +machine had been wrecked in the launching, just how, it was impossible +for me to see. The fact remains that the rear wings and rudder were +wrecked before the machine was free of the ways. Their collapse deprived +the machine of its support in the rear, and it consequently reared up +in front under the action of the motor, assumed a vertical position, +and then toppled over to the rear, falling into the water a few feet in +front of the boat. + +Mr Manly was pulled out of the wreck uninjured and the wrecked +machine--was subsequently placed upon the house-boat, and the whole +brought back to Washington. + +From what has been said it will be seen that these unfortunate accidents +have prevented any test of the apparatus in free flight, and the claim +that an engine-driven, man-carrying aerodrome has been constructed lacks +the proof which actual flight alone can give. + +Having reached the present stage of advancement in its development, it +would seem highly desirable, before laying down the investigation, to +obtain conclusive proof of the possibility of free flight, not only +because there are excellent reasons to hope for success, but because +it marks the end of a definite step toward the attainment of the final +goal. + +Just what further procedure is necessary to secure successful flight +with the large aerodrome has not yet been decided upon. Professor +Langley is understood to have this subject under advisement, and +will doubtless inform the Board of his final conclusions as soon as +practicable. + +In the meantime, to avoid any possible misunderstanding, it should be +stated that even after a successful test of the present great aerodrome, +designed to carry a man, we are still far from the ultimate goal, and it +would seem as if years of constant work and study by experts, together +with the expenditure of thousands of dollars, would still be necessary +before we can hope to produce an apparatus of practical utility on these +lines.--Washington, January 6, 1904. + +A subsequent report of the Board of ordnance and Fortification to the +Secretary of War embodied the principal points in Major Macomb's report, +but as early as March 3rd, 1904, the Board came to a similar conclusion +to that of the French Ministry of War in respect of Clement Ader's work, +stating that it was not 'prepared to make an additional allotment +at this time for continuing the work.' This decision was in no small +measure due to hostile newspaper criticisms. Langley, in a letter to +the press explaining his attitude, stated that he did not wish to make +public the results of his work till these were certain, in consequence +of which he refused admittance to newspaper representatives, and this +attitude produced a hostility which had effect on the United States +Congress. An offer was made to commercialise the invention, but Langley +steadfastly refused it. Concerning this, Manly remarks that Langley +had 'given his time and his best labours to the world without hope of +remuneration, and he could not bring himself, at his stage of life, to +consent to capitalise his scientific work.' + +The final trial of the Langley aerodrome was made on December 8th, 1903; +nine days later, on December 17th, the Wright Brothers made their first +flight in a power-propelled machine, and the conquest of the air was +thus achieved. But for the two accidents that spoilt his trials, the +honour which fell to the Wright Brothers would, beyond doubt, have been +secured by Samuel Pierpoint Langley. + + + + +XI. THE WRIGHT BROTHERS + +Such information as is given here concerning the Wright Brothers is +derived from the two best sources available, namely, the writings of +Wilbur Wright himself, and a lecture given by Dr Griffith Brewer to +members of the Royal Aeronautical Society. There is no doubt that so +far as actual work in connection with aviation accomplished by the two +brothers is concerned, Wilbur Wright's own statements are the clearest +and best available. Apparently Wilbur was, from the beginning, the +historian of the pair, though he himself would have been the last to +attempt to detract in any way from the fame that his brother's work also +deserves. Throughout all their experiments the two were inseparable, +and their work is one indivisible whole; in fact, in every department +of that work, it is impossible to say where Orville leaves off and where +Wilbur begins. + +It is a great story, this of the Wright Brothers, and one worth all the +detail that can be spared it. It begins on the 16th April, 1867, when +Wilbur Wright was born within eight miles of Newcastle, Indiana. Before +Orville's birth on the 19th August, 1871, the Wright family had moved +to Dayton, Ohio, and settled on what is known as the 'West Side' of the +town. Here the brothers grew up, and, when Orville was still a boy in +his teens, he started a printing business, which, as Griffith Brewer +remarks, was only limited by the smallness of his machine and small +quantity of type at his disposal. This machine was in such a state that +pieces of string and wood were incorporated in it by way of repair, but +on it Orville managed to print a boys' paper which gained considerable +popularity in Dayton 'West Side.' Later, at the age of seventeen, +he obtained a more efficient outfit, with which he launched a weekly +newspaper, four pages in size, entitled The West Side News. After three +months' running the paper was increased in size and Wilbur came into +the enterprise as editor, Orville remaining publisher. In 1894 the two +brothers began the publication of a weekly magazine, Snap-Shots, to +which Wilbur contributed a series of articles on local affairs that gave +evidence of the incisive and often sarcastic manner in which he was able +to express himself throughout his life. Dr Griffith Brewer describes him +as a fearless critic, who wrote on matters of local interest in a kindly +but vigorous manner, which did much to maintain the healthy public +municipal life of Dayton. + +Editorial and publishing enterprise was succeeded by the formation, just +across the road from the printing works, of the Wright Cycle Company, +where the two brothers launched out as cycle manufacturers with the +'Van Cleve' bicycle, a machine of great local repute for excellence of +construction, and one which won for itself a reputation that lasted long +after it had ceased to be manufactured. The name of the machine was that +of an ancestor of the brothers, Catherine Van Cleve, who was one of the +first settlers at Dayton, landing there from the River Miami on April +1st, 1796, when the country was virgin forest. + +It was not until 1896 that the mechanical genius which characterised +the two brothers was turned to the consideration of aeronautics. In that +year they took up the problem thoroughly, studying all the aeronautical +information then in print. Lilienthal's writings formed one basis for +their studies, and the work of Langley assisted in establishing in +them a confidence in the possibility of a solution to the problems of +mechanical flight. In 1909, at the banquet given by the Royal Aero Club +to the Wright Brothers on their return to America, after the series of +demonstration flights carried out by Wilbur Wright on the Continent, +Wilbur paid tribute to the great pioneer work of Stringfellow, whose +studies and achievements influenced his own and Orville's early work. He +pointed out how Stringfellow devised an aeroplane having two propellers +and vertical and horizontal steering, and gave due place to this early +pioneer of mechanical flight. + +Neither of the brothers was content with mere study of the work of +others. They collected all the theory available in the books published +up to that time, and then built man-carrying gliders with which to test +the data of Lilienthal and such other authorities as they had consulted. +For two years they conducted outdoor experiments in order to test the +truth or otherwise of what were enunciated as the principles of flight; +after this they turned to laboratory experiments, constructing a wind +tunnel in which they made thousands of tests with models of various +forms of curved planes. From their experiments they tabulated thousands +of readings, which Griffith Brewer remarks as giving results equally +efficient with those of the elaborate tables prepared by learned +institutions. + +Wilbur Wright has set down the beginnings of the practical experiments +made by the two brothers very clearly. 'The difficulties,' he says, +'which obstruct the pathway to success in flying machine construction +are of three general classes: (1) Those which relate to the construction +of the sustaining wings; (2) those which relate to the generation and +application of the power required to drive the machine through the air; +(3) those relating to the balancing and steering of the machine after +it is actually in flight. Of these difficulties two are already to +a certain extent solved. Men already know how to construct wings, or +aeroplanes, which, when driven through the air at sufficient speed, will +not only sustain the weight of the wings themselves, but also that of +the engine and the engineer as well. Men also know how to build engines +and' screws of sufficient lightness and power to drive these planes +at sustaining speed. Inability to balance and steer still confronts +students of the flying problem, although nearly ten years have passed +(since Lilienthal's success). When this one feature has been worked out, +the age of flying machines will have arrived, for all other difficulties +are of minor importance. + +'The person who merely watches the flight of a bird gathers the +impression that the bird has nothing to think of but the flapping of +its wings. As a matter of fact, this is a very small part of its mental +labour. Even to mention all the things the bird must constantly keep in +mind in order to fly securely through the air would take a considerable +time. If I take a piece of paper and, after placing it parallel with +the ground, quickly let it fall, it will not settle steadily down as +a staid, sensible piece of paper ought to do, but it insists on +contravening every recognised rule of decorum, turning over and darting +hither and thither in the most erratic manner, much after the style of +an untrained horse. Yet this is the style of steed that men must learn +to manage before flying can become an everyday sport. The bird has +learned this art of equilibrium, and learned it so thoroughly that its +skill is not apparent to our sight. We only learn to appreciate it when +we can imitate it. + +'Now, there are only two ways of learning to ride a fractious horse: one +is to get on him and learn by actual practice how each motion and trick +may be best met; the other is to sit on a fence and watch the beast +awhile, and then retire to the house and at leisure figure out the best +way of overcoming his jumps and kicks. The latter system is the safer, +but the former, on the whole, turns out the larger proportion of good +riders. It is very much the same in learning to ride a flying machine; +if you are looking for perfect safety you will do well to sit on a fence +and watch the birds, but if you really wish to learn you must mount +a machine and become acquainted with its tricks by actual trial. The +balancing of a gliding or flying machine is very simple in theory. It +merely consists in causing the centre of pressure to coincide with the +centre of gravity.' + +These comments are taken from a lecture delivered by Wilbur Wright +before the Western Society of Engineers in September of 1901, under the +presidency of Octave Chanute. In that lecture Wilbur detailed the way +in which he and his brother came to interest themselves in aeronautical +problems and constructed their first glider. He speaks of his own +notice of the death of Lilienthal in 1896, and of the way in which this +fatality roused him to an active interest in aeronautical problems, +which was stimulated by reading Professor Marey's Animal Mechanism, not +for the first time. 'From this I was led to read more modern works, and +as my brother soon became equally interested with myself, we soon passed +from the reading to the thinking, and finally to the working stage. It +seemed to us that the main reason why the problem had remained so long +unsolved was that no one had been able to obtain any adequate practice. +We figured that Lilienthal in five years of time had spent only about +five hours in actual gliding through the air. The wonder was not that he +had done so little, but that he had accomplished so much. It would not +be considered at all safe for a bicycle rider to attempt to ride through +a crowded city street after only five hours' practice, spread out in +bits of ten seconds each over a period of five years; yet Lilienthal +with this brief practice was remarkably successful in meeting the +fluctuations and eddies of wind-gusts. We thought that if some method +could be found by which it would be possible to practice by the hour +instead of by the second there would be hope of advancing the solution +of a very difficult problem. It seemed feasible to do this by building a +machine which would be sustained at a speed of eighteen miles per hour, +and then finding a locality where winds of this velocity were common. +With these conditions a rope attached to the machine to keep it from +floating backward would answer very nearly the same purpose as a +propeller driven by a motor, and it would be possible to practice by the +hour, and without any serious danger, as it would not be necessary to +rise far from the ground, and the machine would not have any forward +motion at all. We found, according to the accepted tables of air +pressure on curved surfaces, that a machine spreading 200 square feet of +wing surface would be sufficient for our purpose, and that places would +easily be found along the Atlantic coast where winds of sixteen to +twenty-five miles were not at all uncommon. When the winds were low it +was our plan to glide from the tops of sandhills, and when they were +sufficiently strong to use a rope for our motor and fly over one spot. +Our next work was to draw up the plans for a suitable machine. After +much study we finally concluded that tails were a source of trouble +rather than of assistance, and therefore we decided to dispense with +them altogether. It seemed reasonable that if the body of the operator +could be placed in a horizontal position instead of the upright, as in +the machines of Lilienthal, Pilcher, and Chanute, the wind resistance +could be very materially reduced, since only one square foot instead of +five would be exposed. As a full half horse-power would be saved by this +change, we arranged to try at least the horizontal position. Then the +method of control used by Lilienthal, which consisted in shifting the +body, did not seem quite as quick or effective as the case required; so, +after long study, we contrived a system consisting of two large surfaces +on the Chanute double-deck plan, and a smaller surface placed a short +distance in front of the main surfaces in such a position that the +action of the wind upon it would counterbalance the effect of the travel +of the centre of pressure on the main surfaces. Thus changes in the +direction and velocity of the wind would have little disturbing effect, +and the operator would be required to attend only to the steering of the +machine, which was to be effected by curving the forward surface up or +down. The lateral equilibrium and the steering to right or left was +to be attained by a peculiar torsion of the main surfaces which was +equivalent to presenting one end of the wings at a greater angle than +the other. In the main frame a few changes were also made in the details +of construction and trussing employed by Mr Chanute. The most important +of these were: (1) The moving of the forward main crosspiece of the +frame to the extreme front edge; (2) the encasing in the cloth of all +crosspieces and ribs of the surfaces; (3) a rearrangement of the wires +used in trussing the two surfaces together, which rendered it possible +to tighten all the wires by simply shortening two of them.' + +The brothers intended originally to get 200 square feet of supporting +surface for their glider, but the impossibility of obtaining suitable +material compelled them to reduce the area to 165 square feet, which, by +the Lilienthal tables, admitted of support in a wind of about twenty-one +miles an hour at an angle of three degrees. With this glider they went +in the summer of I 1900 to the little settlement of Kitty Hawk, North +Carolina, situated on the strip of land dividing Albemarle Sound from +the Atlantic. Here they reckoned on obtaining steady wind, and here, on +the day that they completed the machine, they took it out for trial as +a kite with the wind blowing at between twenty-five and thirty miles +an hour. They found that in order to support a man on it the glider +required an angle nearer twenty degrees than three, and even with the +wind at thirty miles an hour they could not get down to the planned +angle of three degrees. 'Later, when the wind was too light to support +the machine with a man on it, they tested it as a kite, working the +rudders by cords. Although they obtained satisfactory results in this +way they realised fully that actual gliding experience was necessary +before the tests could be considered practical. + +A series of actual measurements of lift and drift of the machine gave +astonishing results. 'It appeared that the total horizontal pull of the +machine, while sustaining a weight of 52 lbs., was only 8.5 lbs., which +was less than had been previously estimated for head resistance of the +framing alone. Making allowance for the weight carried, it appeared that +the head resistance of the framing was but little more than fifty per +cent of the amount which Mr Chanute had estimated as the head resistance +of the framing of his machine. On the other hand, it appeared sadly +deficient in lifting power as compared with the calculated lift of +curved surfaces of its size... we decided to arrange our machine for the +following year so that the depth of curvature of its surfaces could be +varied at will, and its covering air-proofed.' + +After these experiments the brothers decided to turn to practical +gliding, for which they moved four miles to the south, to the Kill Devil +sandhills, the principal of which is slightly over a hundred feet +in height, with an inclination of nearly ten degrees on its main +north-western slope. On the day after their arrival they made about a +dozen glides, in which, although the landings were made at a speed of +more than twenty miles an hour, no injury was sustained either by the +machine or by the operator. + +'The slope of the hill was 9.5 degrees, or a drop of one foot in six. We +found that after attaining a speed of about twenty-five to thirty miles +with reference to the wind, or ten to fifteen miles over the ground, the +machine not only glided parallel to the slope of the hill, but greatly +increased its speed, thus indicating its ability to glide on a somewhat +less angle than 9.5 degrees, when we should feel it safe to rise higher +from the surface. The control of the machine proved even better than we +had dared to expect, responding quickly to the slightest motion of the +rudder. With these glides our experiments for the year 1900 closed. +Although the hours and hours of practice we had hoped to obtain finally +dwindled down to about two minutes, we were very much pleased with the +general results of the trip, for, setting out as we did with almost +revolutionary theories on many points and an entirely untried form of +machine, we considered it quite a point to be able to return without +having our pet theories completely knocked on the head by the hard logic +of experience, and our own brains dashed out in the bargain. Everything +seemed to us to confirm the correctness of our original opinions: +(1) That practice is the key to the secret of flying; (2) that it +is practicable to assume the horizontal position; (3) that a smaller +surface set at a negative angle in front of the main bearing surfaces, +or wings, will largely counteract the effect of the fore and aft travel +of the centre of pressure; (4) that steering up and down can be attained +with a rudder without moving the position of the operator's body; (5) +that twisting the wings so as to present their ends to the wind at +different angles is a more prompt and efficient way of maintaining +lateral equilibrium than shifting the body of the operator.' + +For the gliding experiments of 1901 it was decided to retain the form of +the 1900 glider, but to increase the area to 308 square feet, which, the +brothers calculated, would support itself and its operator in a wind +of seventeen miles an hour with an angle of incidence of three degrees. +Camp was formed at Kitty Hawk in the middle of July, and on July 27th +the machine was completed and tried for the first time in a wind of +about fourteen miles an hour. The first attempt resulted in landing +after a glide of only a few yards, indicating that the centre of gravity +was too far in front of the centre of pressure. By shifting his position +farther and farther back the operator finally achieved an undulating +flight of a little over 300 feet, but to obtain this success he had to +use full power of the rudder to prevent both stalling and nose-diving. +With the 1900 machine one-fourth of the rudder action had been necessary +for far better control. + +Practically all glides gave the same result, and in one the machine rose +higher and higher until it lost all headway. 'This was the position from +which Lilienthal had always found difficulty in extricating himself, +as his machine then, in spite of his greatest exertions, manifested a +tendency to dive downward almost vertically and strike the ground head +on with frightful velocity. In this case a warning cry from the ground +caused the operator to turn the rudder to its full extent and also to +move his body slightly forward. The machine then settled slowly to the +ground, maintaining its horizontal position almost perfectly, and landed +without any injury at all. This was very encouraging, as it showed that +one of the very greatest dangers in machines with horizontal tails had +been overcome by the use of the front rudder. Several glides later the +same experience was repeated with the same result. In the latter case +the machine had even commenced to move backward, but was nevertheless +brought safely to the ground in a horizontal position. On the whole this +day's experiments were encouraging, for while the action of the rudder +did not seem at all like that of our 1900 machine, yet we had escaped +without difficulty from positions which had proved very dangerous +to preceding experimenters, and after less than one minute's actual +practice had made a glide of more than 300 feet, at an angle of +descent of ten degrees, and with a machine nearly twice as large as had +previously been considered safe. The trouble with its control, which +has been mentioned, we believed could be corrected when we should have +located its cause.' + +It was finally ascertained that the defect could be remedied by +trussing down the ribs of the whole machine so as to reduce the depth of +curvature. When this had been done gliding was resumed, and after a few +trials glides of 366 and 389 feet were made with prompt response on the +part of the machine, even to small movements of the rudder. The rest of +the story of the gliding experiments of 1901 cannot be better told than +in Wilbur Wright's own words, as uttered by him in the lecture from +which the foregoing excerpts have been made. + +'The machine, with its new curvature, never failed to respond promptly +to even small movements of the rudder. The operator could cause it to +almost skim the ground, following the undulations of its surface, or he +could cause it to sail out almost on a level with the starting point, +and, passing high above the foot of the hill, gradually settle down to +the ground. The wind on this day was blowing eleven to fourteen miles +per hour. The next day, the conditions being favourable, the machine +was again taken out for trial. This time the velocity of the wind was +eighteen to twenty-two miles per hour. At first we felt some doubt as to +the safety of attempting free flight in so strong a wind, with a machine +of over 300 square feet and a practice of less than five minutes spent +in actual flight. But after several preliminary experiments we decided +to try a glide. The control of the machine seemed so good that we then +felt no apprehension in sailing boldly forth. And thereafter we made +glide after glide, sometimes following the ground closely and sometimes +sailing high in the air. Mr Chanute had his camera with him and took +pictures of some of these glides, several of which are among those +shown. + +'We made glides on subsequent days, whenever the conditions were +favourable. The highest wind thus experimented in was a little over +twelve metres per second--nearly twenty-seven miles per hour. + +It had been our intention when building the machine to do the larger +part of the experimenting in the following manner:--When the wind blew +seventeen miles an hour, or more, we would attach a rope to the machine +and let it rise as a kite with the operator upon it. When it should +reach a proper height the operator would cast off the rope and glide +down to the ground just as from the top of a hill. In this way we would +be saved the trouble of carrying the machine uphill after each glide, +and could make at least ten glides in the time required for one in the +other way. But when we came to try it, we found that a wind of seventeen +miles, as measured by Richards' anemometer, instead of sustaining the +machine with its operator, a total weight of 240 lbs., at an angle of +incidence of three degrees, in reality would not sustain the machine +alone--100 lbs.--at this angle. Its lifting capacity seemed scarcely one +third of the calculated amount. In order to make sure that this was not +due to the porosity of the cloth, we constructed two small experimental +surfaces of equal size, one of which was air-proofed and the other left +in its natural state; but we could detect no difference in their lifting +powers. For a time we were led to suspect that the lift of curved +surfaces very little exceeded that of planes of the same size, but +further investigation and experiment led to the opinion that (1) the +anemometer used by us over-recorded the true velocity of the wind by +nearly 15 per cent; (2) that the well-known Smeaton co-efficient of.005 +V squared for the wind pressure at 90 degrees is probably too great by +at least 20 per cent; (3) that Lilienthal's estimate that the pressure +on a curved surface having an angle of incidence of 3 degrees equals.545 +of the pressure at go degrees is too large, being nearly 50 per +cent greater than very recent experiments of our own with a pressure +testing-machine indicate; (4) that the superposition of the surfaces +somewhat reduced the lift per square foot, as compared with a single +surface of equal area. + +'In gliding experiments, however, the amount of lift is of less relative +importance than the ratio of lift to drift, as this alone decides +the angle of gliding descent. In a plane the pressure is always +perpendicular to the surface, and the ratio of lift to drift is +therefore the same as that of the cosine to the sine of the angle of +incidence. But in curved surfaces a very remarkable situation is found. +The pressure, instead of being uniformly normal to the chord of the +arc, is usually inclined considerably in front of the perpendicular. +The result is that the lift is greater and the drift less than if +the pressure were normal. Lilienthal was the first to discover this +exceedingly important fact, which is fully set forth in his book, Bird +Flight the Basis of the Flying Art, but owing to some errors in the +methods he used in making measurements, question was raised by other +investigators not only as to the accuracy of his figures, but even as +to the existence of any tangential force at all. Our experiments confirm +the existence of this force, though our measurements differ considerably +from those of Lilienthal. While at Kitty Hawk we spent much time in +measuring the horizontal pressure on our unloaded machine at various +angles of incidence. We found that at 13 degrees the horizontal pressure +was about 23 lbs. This included not only the drift proper, or horizontal +component of the pressure on the side of the surface, but also the head +resistance of the framing as well. The weight of the machine at the time +of this test was about 108 lbs. Now, if the pressure had been normal to +the chord of the surface, the drift proper would have been to the lift +(108 lbs.) as the sine of 13 degrees is to the cosine of 13 degrees, +or.22 X 108/.97 = 24+ lbs.; but this slightly exceeds the total pull +of 23 pounds on our scales. Therefore it is evident that the average +pressure on the surface, instead of being normal to the chord, was so +far inclined toward the front that all the head resistance of framing +and wires used in the construction was more than overcome. In a wind of +fourteen miles per hour resistance is by no means a negligible factor, +so that tangential is evidently a force of considerable value. In a +higher wind, which sustained the machine at an angle of 10 degrees the +pull on the scales was 18 lbs. With the pressure normal to the chord the +drift proper would have been 17 X 98/.98. The travel of the centre of +pressure made it necessary to put sand on the front rudder to bring +the centres of gravity and pressure into coincidence, consequently the +weight of the machine varied from 98 lbs. to 108 lbs. in the different +tests= 17 lbs., so that, although the higher wind velocity must have +caused an increase in the head resistance, the tangential force still +came within 1 lb. of overcoming it. After our return from Kitty Hawk +we began a series of experiments to accurately determine the amount and +direction of the pressure produced on curved surfaces when acted upon by +winds at the various angles from zero to 90 degrees. These experiments +are not yet concluded, but in general they support Lilienthal in the +claim that the curves give pressures more favourable in amount and +direction than planes; but we find marked differences in the exact +values, especially at angles below 10 degrees. We were unable to obtain +direct measurements of the horizontal pressures of the machine with +the operator on board, but by comparing the distance travelled with the +vertical fall, it was easily calculated that at a speed of 24 miles per +hour the total horizontal resistances of our machine, when bearing +the operator, amounted to 40 lbs., which is equivalent to about 2 1/3 +horse-power. It must not be supposed, however, that a motor developing +this power would be sufficient to drive a man-bearing machine. The extra +weight of the motor would require either a larger machine, higher speed, +or a greater angle of incidence in order to support it, and therefore +more power. It is probable, however, that an engine of 6 horse-power, +weighing 100 lbs. would answer the purpose. Such an engine is entirely +practicable. Indeed, working motors of one-half this weight per +horse-power (9 lbs. per horse-power) have been constructed by several +different builders. Increasing the speed of our machine from 24 to 33 +miles per hour reduced the total horizontal pressure from 40 to about 35 +lbs. This was quite an advantage in gliding, as it made it possible to +sail about 15 per cent farther with a given drop. However, it would +be of little or no advantage in reducing the size of the motor in +a power-driven machine, because the lessened thrust would be +counterbalanced by the increased speed per minute. Some years ago +Professor Langley called attention to the great economy of thrust which +might be obtained by using very high speeds, and from this many were led +to suppose that high speed was essential to success in a motor-driven +machine. But the economy to which Professor Langley called attention was +in foot pounds per mile of travel, not in foot pounds per minute. It +is the foot pounds per minute that fixes the size of the motor. The +probability is that the first flying machines will have a relatively low +speed, perhaps not much exceeding 20 miles per hour, but the problem of +increasing the speed will be much simpler in some respects than that of +increasing the speed of a steamboat; for, whereas in the latter case the +size of the engine must increase as the cube of the speed, in the flying +machine, until extremely high speeds are reached, the capacity of the +motor increases in less than simple ratio; and there is even a decrease +in the fuel per mile of travel. In other words, to double the speed of +a steamship (and the same is true of the balloon type of airship) eight +times the engine and boiler capacity would be required, and four times +the fuel consumption per mile of travel: while a flying machine would +require engines of less than double the size, and there would be an +actual decrease in the fuel consumption per mile of travel. But looking +at the matter conversely, the great disadvantage of the flying machine +is apparent; for in the latter no flight at all is possible unless the +proportion of horse-power to flying capacity is very high; but on +the other hand a steamship is a mechanical success if its ratio of +horse-power to tonnage is insignificant. A flying machine that would fly +at a speed of 50 miles per hour with engines of 1,000 horse-power would +not be upheld by its wings at all at a speed of less than 25 miles +an hour, and nothing less than 500 horse-power could drive it at this +speed. But a boat which could make 40 miles an hour with engines of +1,000 horse-power would still move 4 miles an hour even if the engines +were reduced to 1 horse-power. The problems of land and water travel +were solved in the nineteenth century, because it was possible to begin +with small achievements, and gradually work up to our present success. +The flying problem was left over to the twentieth century, because in +this case the art must be highly developed before any flight of any +considerable duration at all can be obtained. + +'However, there is another way of flying which requires no artificial +motor, and many workers believe that success will come first by this +road. I refer to the soaring flight, by which the machine is permanently +sustained in the air by the same means that are employed by soaring +birds. They spread their wings to the wind, and sail by the hour, +with no perceptible exertion beyond that required to balance and steer +themselves. What sustains them is not definitely known, though it is +almost certain that it is a rising current of air. But whether it be a +rising current or something else, it is as well able to support a +flying machine as a bird, if man once learns the art of utilising it. +In gliding experiments it has long been known that the rate of vertical +descent is very much retarded, and the duration of the flight greatly +prolonged, if a strong wind blows UP the face of the hill parallel +to its surface. Our machine, when gliding in still air, has a rate of +vertical descent of nearly 6 feet per second, while in a wind blowing +26 miles per hour up a steep hill we made glides in which the rate of +descent was less than 2 feet per second. And during the larger part of +this time, while the machine remained exactly in the rising current, +THERE WAS NO DESCENT AT ALL, BUT EVEN A SLIGHT RISE. If the operator +had had sufficient skill to keep himself from passing beyond the rising +current he would have been sustained indefinitely at a higher point than +that from which he started. The illustration shows one of these very +slow glides at a time when the machine was practically at a standstill. +The failure to advance more rapidly caused the photographer some trouble +in aiming, as you will perceive. In looking at this picture you will +readily understand that the excitement of gliding experiments does +not entirely cease with the breaking up of camp. In the photographic +dark-room at home we pass moments of as thrilling interest as any in +the field, when the image begins to appear on the plate and it is yet an +open question whether we have a picture of a flying machine or merely a +patch of open sky. These slow glides in rising current probably hold out +greater hope of extensive practice than any other method within man's +reach, but they have the disadvantage of requiring rather strong winds +or very large supporting surfaces. However, when gliding operators +have attained greater skill, they can with comparative safety maintain +themselves in the air for hours at a time in this way, and thus by +constant practice so increase their knowledge and skill that they can +rise into the higher air and search out the currents which enable the +soaring birds to transport themselves to any desired point by first +rising in a circle and then sailing off at a descending angle. This +illustration shows the machine, alone, flying in a wind of 35 miles per +hour on the face of a steep hill, 100 feet high. It will be seen +that the machine not only pulls upward, but also pulls forward in the +direction from which the wind blows, thus overcoming both gravity and +the speed of the wind. We tried the same experiment with a man on it, +but found danger that the forward pull would become so strong, that the +men holding the ropes would be dragged from their insecure foothold on +the slope of the hill. So this form of experimenting was discontinued +after four or five minutes' trial. + +'In looking over our experiments of the past two years, with models and +full-size machines, the following points stand out with clearness:-- + +'1. That the lifting power of a large machine, held stationary in a wind +at a small distance from the earth, is much less than the Lilienthal +table and our own laboratory experiments would lead us to expect. When +the machine is moved through the air, as in gliding, the discrepancy +seems much less marked. + +'2. That the ratio of drift to lift in well-shaped surfaces is less at +angles of incidence of 5 degrees to 12 degrees than at an angle of 3 +degrees. + +'3. That in arched surfaces the centre of pressure at 90 degrees is near +the centre of the surface, but moves slowly forward as the angle becomes +less, till a critical angle varying with the shape and depth of the +curve is reached, after which it moves rapidly toward the rear till the +angle of no lift is found. + +'4. That with similar conditions large surfaces may be controlled with +not much greater difficulty than small ones, if the control is effected +by manipulation of the surfaces themselves, rather than by a movement of +the body of the operator. + +'5. That the head resistances of the framing can be brought to a point +much below that usually estimated as necessary. + +'6. That tails, both vertical and horizontal, may with safety be +eliminated in gliding and other flying experiments. + +'7. That a horizontal position of the operator's body may be assumed +without excessive danger, and thus the head resistance reduced to about +one-fifth that of the upright position. + +'8. That a pair of superposed, or tandem surfaces, has less lift in +proportion to drift than either surface separately, even after making +allowance for weight and head resistance of the connections.' + +Thus, to the end of the 1901 experiments, Wilbur Wright provided a +fairly full account of what was accomplished; the record shows an amount +of patient and painstaking work almost beyond belief--it was no question +of making a plane and launching it, but a business of trial and error, +investigation and tabulation of detail, and the rejection time after +time of previously accepted theories, till the brothers must have felt +the the solid earth was no longer secure, at times. Though it was Wilbur +who set down this and other records of the work done, yet the actual +work was so much Orville's as his brother's that no analysis could +separate any set of experiments and say that Orville did this and Wilbur +that--the two were inseparable. On this point Griffith Brewer remarked +that 'in the arguments, if one brother took one view, the other brother +took the opposite view as a matter of course, and the subject was +thrashed to pieces until a mutually acceptable result remained. I have +often been asked since these pioneer days, "Tell me, Brewer, who was +really the originator of those two?" In reply, I used first to say, +"I think it was mostly Wilbur," and later, when I came to know Orville +better, I said, "The thing could not have been without Orville." Now, +when asked, I have to say, "I don't know," and I feel the more I think +of it that it was only the wonderful combination of these two brothers, +who devoted their lives together or this common object, that made the +discovery of the art of flying possible.' + +Beyond the 1901 experiments in gliding, the record grows more scrappy, +less detailed. It appears that once power-driven flight had been +achieved, the brothers were not so willing to talk as before; +considering the amount of work that they put in, there could have been +little time for verbal description of that work--as already remarked, +their tables still stand for the designer and experimenter. The end of +the 1901 experiments left both brothers somewhat discouraged, though +they had accomplished more than any others. 'Having set out with +absolute faith in the existing scientific data, we ere driven to doubt +one thing after another, finally, after two years of experiment, we cast +it all aside, and decided to rely entirely on our own investigations. +Truth and error were everywhere so intimately mixed as to be +indistinguishable.... We had taken up aeronautics as a sport. We +reluctantly entered upon the scientific side of it.' + +Yet, driven thus to the more serious aspect of the work, they found in +the step its own reward, for the work of itself drew them on and on, to +the construction of measuring machines for the avoidance of error, and +to the making of series after series of measurements, concerning which +Wilbur wrote in 1908 (in the Century Magazine) that 'after making +preliminary measurements on a great number of different shaped surfaces, +to secure a general understanding of the subject, we began systematic +measurements of standard surfaces, so varied in design as to bring +out the underlying causes of differences noted in their pressures. +Measurements were tabulated on nearly fifty of these at all angles from +zero to 45 degrees, at intervals of 2 1/2 degrees. Measurements were +also secured showing the effects on each other when surfaces are +superposed, or when they follow one another. + +'Some strange results were obtained. One surface, with a heavy roll at +the front edge, showed the same lift for all angles from 7 1/2 to 45 +degrees. This seemed so anomalous that we were almost ready to doubt our +own measurements, when a simple test was suggested. A weather vane, with +two planes attached to the pointer at an angle of 80 degrees with +each other, was made. According to our table, such a vane would be in +unstable equilibrium when pointing directly into the wind, for if by +chance the wind should happen to strike one plane at 39 degrees and the +other at 41 degrees, the plane with the smaller angle would have the +greater pressure and the pointer would be turned still farther out +of the course of the wind until the two vanes again secured equal +pressures, which would be at approximately 30 and 50 degrees. But the +vane performed in this very manner. Further corroboration of the tables +was obtained in experiments with the new glider at Kill Devil Hill the +next season. + +'In September and October, 1902 nearly 1,000 gliding flights were made, +several of which covered distances of over 600 feet. Some, made against +a wind of 36 miles an hour, gave proof of the effectiveness of the +devices for control. With this machine, in the autumn of 1903, we made +a number of flights in which we remained in the air for over a minute, +often soaring for a considerable time in one spot, without any descent +at all. Little wonder that our unscientific assistant should think the +only thing needed to keep it indefinitely in the air would be a coat of +feathers to make it light!' + +It was at the conclusion of these experiments of 1903 that the brothers +concluded they had obtained sufficient data from their thousands of +glides and multitude of calculations to permit of their constructing +and making trial of a power-driven machine. The first designs got out +provided for a total weight of 600 lbs., which was to include the weight +of the motor and the pilot; but on completion it was found that there +was a surplus of power from the motor, and thus they had 150 lbs. weight +to allow for strengthening wings and other parts. + +They came up against the problem to which Riach has since devoted so +much attention, that of propeller design. 'We had thought of getting the +theory of the screw-propeller from the marine engineers, and then, by +applying our table of air-pressures to their formulae, of designing +air-propellers suitable for our uses. But, so far as we could learn, the +marine engineers possessed only empirical formulae, and the exact action +of the screw propeller, after a century of use, was still very obscure. +As we were not in a position to undertake a long series of practical +experiments to discover a propeller suitable for our machine, it seemed +necessary to obtain such a thorough understanding of the theory of its +reactions as would enable us to design them from calculation alone. +What at first seemed a simple problem became more complex the longer we +studied it. With the machine moving forward, the air flying backward, +the propellers turning sidewise, and nothing standing still, it seemed +impossible to find a starting point from which to trace the various +simultaneous reactions. Contemplation of it was confusing. After long +arguments we often found ourselves in the ludicrous position of each +having been converted to the other's side, with no more agreement than +when the discussion began. + +'It was not till several months had passed, and every phase of the +problem had been thrashed over and over, that the various reactions +began to untangle themselves. When once a clear understanding had been +obtained there was no difficulty in designing a suitable propeller, with +proper diameter, pitch, and area of blade, to meet the requirements of +the flier. High efficiency in a screw-propeller is not dependent upon +any particular or peculiar shape, and there is no such thing as a "best" +screw. A propeller giving a high dynamic efficiency when used upon one +machine may be almost worthless when used upon another. The propeller +should in every case be designed to meet the particular conditions of +the machine to which it is to be applied. Our first propellers, built +entirely from calculation, gave in useful work 66 per cent of the power +expended. This was about one-third more than had been secured by Maxim +or Langley.' + +Langley had made his last attempt with the 'aerodrome,' and his splendid +failure but a few days before the brothers made their first attempt at +power-driven aeroplane flight. On December 17th, 1903, the machine was +taken out; in addition to Wilbur and Orville Wright, there were present +five spectators: Mr A. D. Etheridge, of the Kill Devil life-saving +station; Mr W. S.Dough, Mr W. C. Brinkley, of Manteo; Mr John Ward, of +Naghead, and Mr John T. Daniels.[*] A general invitation had been given +to practically all the residents in the vicinity, but the Kill Devil +district is a cold area in December, and history had recorded so many +experiments in which machines had failed to leave the ground that +between temperature and scepticism only these five risked a waste of +their time. + +[*] This list is as given by Wilbur Wright himself. + +And these five were in at the greatest conquest man had made since James +Watt evolved the steam engine--perhaps even a greater conquest than that +of Watt. Four flights in all were made; the first lasted only twelve +seconds, 'the first in the history of the world in which a machine +carrying a man had raised itself into the air by its own power in free +flight, had sailed forward on a level course without reduction of +speed, and had finally landed without being wrecked,' said Wilbur +Wright concerning the achievement.[*] The next two flights were slightly +longer, and the fourth and last of the day was one second short of the +complete minute; it was made into the teeth of a 20 mile an hour wind, +and the distance travelled was 852 feet. + +[*] Century Magazine, September, 1908. + +This bald statement of the day's doings is as Wilbur Wright himself +has given it, and there is in truth nothing more to say; no amount of +statement could add to the importance of the achievement, and no more +than the bare record is necessary. The faith that had inspired the long +roll of pioneers, from da Vinci onward, was justified at last. + +Having made their conquest, the brothers took the machine back to camp, +and, as they thought, placed it in safety. Talking with the little group +of spectators about the flights, they forgot about the machine, and then +a sudden gust of wind struck it. Seeing that it was being overturned, +all made a rush toward it to save it, and Mr Daniels, a man of large +proportions, was in some way lifted off his feet, falling between the +planes. The machine overturned fully, and Daniels was shaken like a die +in a cup as the wind rolled the machine over and over--he came out at +the end of his experience with a series of bad bruises, and no more, but +the damage done to the machine by the accident was sufficient to render +it useless for further experiment that season. + +A new machine, stronger and heavier, was constructed by the brothers, +and in the spring of 1904 they began experiments again at Sims +Station, eight miles to the east of Dayton, their home town. Press +representatives were invited for the first trial, and about a dozen +came--the whole gathering did not number more than fifty people. 'When +preparations had been concluded,' Wilbur Wright wrote of this trial, 'a +wind of only three or four miles an hour was blowing--insufficient for +starting on so short a track--but since many had come a long way to +see the machine in action, an attempt was made. To add to the other +difficulty, the engine refused to work properly. The machine, after +running the length of the track, slid off the end without rising into +the air at all. Several of the newspaper men returned next day but were +again disappointed. The engine performed badly, and after a glide of +only sixty feet the machine again came to the ground. Further trial was +postponed till the motor could be put in better running condition. The +reporters had now, no doubt, lost confidence in the machine, though +their reports, in kindness, concealed it. Later, when they heard that +we were making flights of several minutes' duration, knowing that longer +flights had been made with airships, and not knowing any essential +difference between airships and flying machines, they were but little +interested. + +'We had not been flying long in 1904 before we found that the problem of +equilibrium had not as yet been entirely solved. Sometimes, in making +a circle, the machine would turn over sidewise despite anything the +operator could do, although, under the same conditions in ordinary +straight flight it could have been righted in an instant. In one flight, +in 1905, while circling round a honey locust-tree at a height of about +50 feet, the machine suddenly began to turn up on one wing, and took a +course toward the tree. The operator, not relishing the idea of landing +in a thorn tree, attempted to reach the ground. The left wing, however, +struck the tree at a height of 10 or 12 feet from the ground and carried +away several branches; but the flight, which had already covered a +distance of six miles, was continued to the starting point. + +'The causes of these troubles--too technical for explanation here--were +not entirely overcome till the end of September, 1905. The flights then +rapidly increased in length, till experiments were discontinued after +October 5 on account of the number of people attracted to the field. +Although made on a ground open on every side, and bordered on two sides +by much-travelled thoroughfares, with electric cars passing every hour, +and seen by all the people living in the neighbourhood for miles around, +and by several hundred others, yet these flights have been made by some +newspapers the subject of a great "mystery."' + +Viewing their work from the financial side, the two brothers incurred +but little expense in the earlier gliding experiments, and, indeed, +viewed these only as recreation, limiting their expenditure to that +which two men might spend on any hobby. When they had once achieved +successful power-driven flight, they saw the possibilities of their +work, and abandoned such other business as had engaged their energies, +sinking all their capital in the development of a practical flying +machine. Having, in 1905, improved their designs to such an extent that +they could consider their machine a practical aeroplane, they devoted +the years 1906 and 1907 to business negotiations and to the construction +of new machines, resuming flying experiments in May of 1908 in order to +test the ability of their machine to meet the requirements of a contract +they had made with the United States Government, which required an +aeroplane capable of carrying two men, together with sufficient fuel +supplies for a flight of 125 miles at 40 miles per hour. Practically +similar to the machine used in the experiments of 1905, the contract +aeroplane was fitted with a larger motor, and provision was made for +seating a passenger and also for allowing of the operator assuming a +sitting position, instead of lying prone. + +Before leaving the work of the brothers to consider contemporary events, +it may be noted that they claimed--with justice--that they were first to +construct wings adjustable to different angles of incidence on the right +and left side in order to control the balance of an aeroplane; the +first to attain lateral balance by adjusting wing-tips to respectively +different angles of incidence on the right and left sides, and the first +to use a vertical vane in combination with wing-tips, adjustable to +respectively different angles of incidence, in balancing and steering +an aeroplane. They were first, too, to use a movable vertical tail, in +combination with wings adjustable to different angles of incidence, in +controlling the balance and direction of an aeroplane.[*] + +[*]Aeronautical Journal, No. 79. + +A certain Henry M. Weaver, who went to see the work of the brothers, +writing in a letter which was subsequently read before the Aero Club de +France records that he had a talk in 1905 with the farmer who rented the +field in which the Wrights made their flights.' On October 5th (1905) he +was cutting corn in the next field east, which is higher ground. When +he noticed the aeroplane had started on its flight he remarked to his +helper: "Well, the boys are at it again," and kept on cutting corn, at +the same time keeping an eye on the great white form rushing about its +course. "I just kept on shocking corn," he continued, "until I got down +to the fence, and the durned thing was still going round. I thought it +would never stop."' + +He was right. The brothers started it, and it will never stop. + +Mr Weaver also notes briefly the construction of the 1905 Wright flier. +'The frame was made of larch wood-from tip to tip of the wings the +dimension was 40 feet. The gasoline motor--a special construction +made by them--much the same, though, as the motor on the Pope-Toledo +automobile--was of from 12 to 15 horse-power. The motor weighed 240 lbs. +The frame was covered with ordinary muslin of good quality. No attempt +was made to lighten the machine; they simply built it strong enough +to stand the shocks. The structure stood on skids or runners, like a +sleigh. These held the frame high enough from the ground in alighting +to protect the blades of the propeller. Complete with motor, the machine +weighed 925 lbs. + + + + +XII. THE FIRST YEARS OF CONQUEST + +It is no derogation of the work accomplished by the Wright Brothers to +say that they won the honour of the first power-propelled flights in +a heavier-than-air machine only by a short period. In Europe, and +especially in France, independent experiment was being conducted by +Ferber, by Santos-Dumont, and others, while in England Cody was not far +behind the other giants of those days. The history of the early years +of controlled power flights is a tangle of half-records; there were no +chroniclers, only workers, and much of what was done goes unrecorded +perforce, since it was not set down at the time. + +Before passing to survey of those early years, let it be set down that +in 1907, when the Wright Brothers had proved the practicability of their +machines, negotiations were entered into between the brothers and +the British War office. On April 12th 1907, the apostle of military +stagnation, Haldane, then War Minister, put an end to the negotiations +by declaring that 'the War office is not disposed to enter into +relations at present with any manufacturer of aeroplanes' The state +of the British air service in 1914 at the outbreak of hostilities, is +eloquent regarding the pursuance of the policy which Haldane initiated. + +'If I talked a lot,' said Wilbur Wright once, 'I should be like the +parrot, which is the bird that speaks most and flies least.' That +attitude is emblematic of the majority of the early fliers, and because +of it the record of their achievements is incomplete to-day. Ferber, +for instance, has left little from which to state what he did, and that +little is scattered through various periodicals, scrappily enough. A +French army officer, Captain Ferber was experimenting with monoplane +and biplane gliders at the beginning of the century-his work was +contemporary with that of the Wrights. He corresponded both with Chanute +and with the Wrights, and in the end he was commissioned by the +French Ministry of War to undertake the journey to America in order +to negotiate with the Wright Brothers concerning French rights in the +patents they had acquired, and to study their work at first hand. + +Ferber's experiments in gliding began in 1899 at the Military School at +Fountainebleau, with a canvas glider of some 80 square feet supporting +surface, and weighing 65 lbs. Two years later he constructed a larger +and more satisfactory machine, with which he made numerous excellent +glides. Later, he constructed an apparatus which suspended a plane from +a long arm which swung on a tower, in order that experiments might be +carried out without risk to the experimenter, and it was not until 1905 +that he attempted power-driven free flight. He took up the Voisin design +of biplane for his power-driven flights, and virtually devoted all his +energies to the study of aeronautics. His book, Aviation, its Dawn +and Development, is a work of scientific value--unlike many of his +contemporaries, Ferber brought to the study of the problems of flight a +trained mind, and he was concerned equally with the theoretical problems +of aeronautics and the practical aspects of the subject. + +After Bleriot's successful cross-Channel flight, it was proposed to +offer a prize of L1,000 for the feat which C. S. Rolls subsequently +accomplished (starting from the English side of the Channel), a flight +from Boulogne to Dover and back; in place of this, however, an aviation +week at Boulogne was organised, but, although numerous aviators were +invited to compete, the condition of the flying grounds was such that +no competitions took place. Ferber was virtually the only one to do any +flying at Boulogne, and at the outset he had his first accident; after +what was for those days a good flight, he made a series of circles +with his machine, when it suddenly struck the ground, being partially +wrecked. Repairs were carried out, and Ferber resumed his exhibition +flights, carrying on up to Wednesday, September 22nd, 1909. On that day +he remained in the air for half an hour, and, as he was about to land, +the machine struck a mound of earth and overturned, pinning Ferber under +the weight of the motor. After being extricated, Ferber seemed to show +little concern at the accident, but in a few minutes he complained of +great pain, when he was conveyed to the ambulance shed on the ground. + +'I was foolish,' he told those who were with him there. 'I was flying +too low. It was my own fault and it will be a severe lesson to me. +I wanted to turn round, and was only five metres from the ground.' A +little after this, he got up from the couch on which he had been placed, +and almost immediately collapsed, dying five minutes later. + +Ferber's chief contemporaries in France were Santos-Dumont, of airship +fame, Henri and Maurice Farman, Hubert Latham, Ernest Archdeacon, and +Delagrange. These are names that come at once to mind, as does that of +Bleriot, who accomplished the second great feat of power-driven flight, +but as a matter of fact the years 1903-10 are filled with a little host +of investigators and experimenters, many of whom, although their names +do not survive to any extent, are but a very little way behind those +mentioned here in enthusiasm and devotion. Archdeacon and Gabriel +Voisin, the former of whom took to heart the success achieved by the +Wright Brothers, co-operated in experiments in gliding. Archdeacon +constructed a glider in box-kite fashion, and Voisin experimented with +it on the Seine, the glider being towed by a motorboat to attain the +necessary speed. It was Archdeacon who offered a cup for the first +straight flight of 200 metres, which was won by Santos-Dumont, and he +also combined with Henri Deutsch de la Meurthe in giving the prize for +the first circular flight of a mile, which was won by Henry Farman on +January 13th, 1908. + +A history of the development of aviation in France in these, the +strenuous years, would fill volumes in itself. Bleriot was carrying +out experiments with a biplane glider on the Seine, and Robert +Esnault-Pelterie was working on the lines of the Wright Brothers, +bringing American practice to France. In America others besides the +Wrights had wakened to the possibilities of heavier-than-air flight; +Glenn Curtiss, in company with Dr Alexander Graham Bell, with J. A. D. +McCurdy, and with F. W. Baldwin, a Canadian engineer, formed the Aerial +Experiment Company, which built a number of aeroplanes, most famous of +which were the 'June Bug,' the 'Red Wing,' and the 'White Wing.' In 1908 +the 'June Bug 'won a cup presented by the Scientific American--it was +the first prize offered in America in connection with aeroplane flight. + +Among the little group of French experimenters in these first years of +practical flight, Santos-Dumont takes high rank. He built his 'No. 14 +bis' aeroplane in biplane form, with two superposed main plane surfaces, +and fitted it with an eight-cylinder Antoinette motor driving a +two-bladed aluminium propeller, of which the blades were 6 feet only +from tip to tip. The total lift surface of 860 square feet was given +with a wing-span of a little under 40 feet, and the weight of the +complete machine was 353 lbs., of which the engine weighed 158 lbs. +In July of 1906 Santos-Dumont flew a distance of a few yards in this +machine, but damaged it in striking the ground; on October 23rd of the +same year he made a flight of nearly 200 feet--which might have been +longer, but that he feared a crowd in front of the aeroplane and cut +off his ignition. This may be regarded as the first effective flight in +Europe, and by it Santos-Dumont takes his place as one of the chief--if +not the chief--of the pioneers of the first years of practical flight, +so far as Europe is concerned. + +Meanwhile, the Voisin Brothers, who in 1904 made cellular kites for +Archdeacon to test by towing on the Seine from a motor launch, obtained +data for the construction of the aeroplane which Delagrange and Henry +Farman were to use later. The Voisin was a biplane, constructed with +due regard to the designs of Langley, Lilienthal, and other earlier +experimenters--both the Voisins and M. Colliex, their engineer, studied +Lilienthal pretty exhaustively in getting out their design, though their +own researches were very thorough as well. The weight of this Voisin +biplane was about 1,450 lbs., and its maximum speed was some 38 to 40 +miles per hour, the total supporting surface being about 535 square +feet. It differed from the Wright design in the possession of a +tail-piece, a characteristic which marked all the French school of early +design as in opposition to the American. The Wright machine got its +longitudinal stability by means of the main planes and the elevating +planes, while the Voisin type added a third factor of stability in its +sailplanes. Further, the Voisins fitted their biplane with a wheeled +undercarriage, while the Wright machine, being fitted only with runners, +demanded a launching rail for starting. Whether a machine should be +tailless or tailed was for some long time matter for acute controversy, +which in the end was settled by the fitting of a tail to the Wright +machines-France won the dispute by the concession. + +Henry Farman, who began his flying career with a Voisin machine, evolved +from it the aeroplane which bore his name, following the main lines of +the Voisin type fairly closely, but making alterations in the controls, +and in the design of the undercarriage, which was somewhat elaborated, +even to the inclusion of shock absorbers. The seven-cylinder 50 +horse-power Gnome rotary engine was fitted to the Farman machine--the +Voisins had fitted an eight-cylinder Antoinette, giving 50 horse-power +at 1,100 revolutions per minute, with direct drive to the propeller. +Farman reduced the weight of the machine from the 1,450 lbs. of the +Voisins to some 1,010 lbs. or thereabouts, and the supporting area to +450 square feet. This machine won its chief fame with Paulhan as pilot +in the famous London to Manchester flight--it is to be remarked, too, +that Farman himself was the first man in Europe to accomplish a flight +of a mile. + +Other notable designs of these early days were the 'R.E.P.', Esnault +Pelterie's machine, and the Curtiss-Herring biplane. Of these Esnault +Pelterie's was a monoplane, designed in that form since Esnault Pelterie +had found by experiment that the wire used in bracing offers far more +resistance to the air than its dimensions would seem to warrant. He +built the wings of sufficient strength to stand the strain of flight +without bracing wires, and dependent only for their support on the +points of attachment to the body of the machine; for the rest, it +carried its propeller in front of the planes, and both horizontal and +vertical rudders at the stern--a distinct departure from the Wright +and similar types. One wheel only was fixed under the body where the +undercarriage exists on a normal design, but light wheels were fixed, +one at the extremity of each wing, and there was also a wheel under the +tail portion of the machine. A single lever actuated all the controls +for steering. With a supporting surface of 150 square feet the machine +weighed 946 lbs., about 6.4 lbs. per square foot of lifting surface. + +The Curtiss biplane, as flown by Glenn Curtiss at the Rheims meeting, +was built with a bamboo framework, stayed by means of very fine +steel-stranded cables. A--then--novel feature of the machine was the +moving of the ailerons by the pilot leaning to one side or the other in +his seat, a light, tubular arm-rest being pressed by his body when he +leaned to one side or the other, and thus operating the movement of the +ailerons employed for tilting the plane when turning. A steering-wheel +fitted immediately in front of the pilot's seat served to operate a rear +steering-rudder when the wheel was turned in either direction, while +pulling back the wheel altered the inclination of the front elevating +planes, and so gave lifting or depressing control of the plane. + +This machine ran on three wheels before leaving the ground, a central +undercarriage wheel being fitted in front, with two more in line with +a right angle line drawn through the centre of the engine crank at the +rear end of the crank-case. The engine was a 35 horsepower Vee design, +water cooled, with overhead inlet and exhaust valves, and Bosch +high-tension magneto ignition. The total weight of the plane in flying +order was about 700 lbs. + +As great a figure in the early days as either Ferber or Santos-Dumont +was Louis Bleriot, who, as early as 1900 built a flapping-wing model, +this before ever he came to experimenting with the Voisin biplane type +of glider on the Seine. Up to 1906 he had built four biplanes of his own +design, and in March of 1907 he built his first monoplane, to wreck +it only a few days after completion in an accident from which he had +a fortunate escape. His next machine was a double monoplane, designed +after Langley's precept, to a certain extent, and this was totally +wrecked in September of 1907. His seventh machine, a monoplane, was +built within a month of this accident, and with this he had a number +of mishaps, also achieving some good flights, including one in which +he made a turn. It was wrecked in December of 1907, whereupon he built +another monoplane on which, on July 6th, 1908, Bleriot made a flight +lasting eight and a half minutes. In October of that year he flew the +machine from Toury to Artenay and returned on it--this was just a day +after Farman's first cross-country flight--but, trying to repeat the +success five days later, Bleriot collided with a tree in a fog and +wrecked the machine past repair. Thereupon he set about building his +eleventh machine, with which he was to achieve the first flight across +the English channel. + +Henry Farman, to whom reference has already been made, was engaged with +his two brothers, Maurice and Richard, in the motor-car business, and +turned to active interest in flying in 1907, when the Voisin firm built +his first biplane on the box-kite principle. In July of 1908 he won +a prize of L400 for a flight of thirteen miles, previously having +completed the first kilometre flown in Europe with a passenger, the said +passenger being Ernest Archdeaon. In September of 1908 Farman put up a +speed record of forty miles an hour in a flight lasting forty minutes. + +Santos-Dumont produced the famous 'Demoiselle' monoplane early in 1909, +a tiny machine in which the pilot had his seat in a sort of miniature +cage under the main plane. It was a very fast, light little machine but +was difficult to fly, and owing to its small wingspread was unable +to glide at a reasonably safe angle. There has probably never been a +cheaper flying machine to build than the 'Demoiselle,' which could be so +upset as to seem completely wrecked, and then repaired ready for further +flight by a couple of hours' work. Santos-Dumont retained no patent +in the design, but gave it out freely to any one who chose to build +'Demoiselles'; the vogue of the pattern was brief, owing to the +difficulty of piloting the machine. + +These were the years of records, broken almost as soon as made. There +was Farman's mile, there was the flight of the Comte de Lambert over the +Eiffel Tower, Latham's flight at Blackpool in a high wind, the Rheims +records, and then Henry Farman's flight of four hours later in 1909, +Orville Wright's height record of 1,640 feet, and Delagrange's speed +record of 49.9 miles per hour. The coming to fame of the Gnome rotary +engine helped in the making of these records to a very great extent, +for in this engine was a prime mover which gave the reliability that +aeroplane builders and pilots had been searching for, but vainly. The +Wrights and Glenn Curtiss, of course, had their own designs of engine, +but the Gnome, in spite of its lack of economy in fuel and oil, and its +high cost, soon came to be regarded as the best power plant for flight. + +Delagrange, one of the very good pilots of the early days, provided a +curious insight to the way in which flying was regarded, at the opening +of the Juvisy aero aerodrome in May of 1909. A huge crowd had gathered +for the first day's flying, and nine machines were announced to appear, +but only three were brought out. Delagrange made what was considered an +indifferent little flight, and another pilot, one De Bischoff, attempted +to rise, but could not get his machine off the ground. Thereupon the +crowd of 30,000 people lost their tempers, broke down the barriers +surrounding the flying course, and hissed the officials, who were quite +unable to maintain order. Delagrange, however, saved the situation +by making a circuit of the course at a height of thirty feet from the +ground, which won him rounds of cheering and restored the crowd to +good humour. Possibly the smash achieved by Rougier, the famous racing +motorist, who crashed his Voisin biplane after Delagrange had made his +circuit, completed the enjoyment of the spectators. Delagrange, flying +at Argentan in June of 1909, made a flight of four kilometres at a +height of sixty feet; for those days this was a noteworthy performance. +Contemporary with this was Hubert Latham's flight of an hour and seven +minutes on an Antoinette monoplane; this won the adjective 'magnificent' +from contemporary recorders of aviation. + +Viewing the work of the little group of French experimenters, it is, +at this length of time from their exploits, difficult to see why +they carried the art as far as they did. There was in it little of +satisfaction, a certain measure of fame, and practically no profit--the +giants of those days got very little for their pains. Delagrange's +experience at the opening of the Juvisy ground was symptomatic of the +way in which flight was regarded by the great mass of people--it was a +sport, and nothing more, but a sport without the dividends attaching +to professional football or horse-racing. For a brief period, after the +Rheims meeting, there was a golden harvest to be reaped by the best of +the pilots. Henry Farman asked L2,000 for a week's exhibition flying in +England, and Paulhan asked half that sum, but a rapid increase in +the number of capable pilots, together with the fact that most flying +meetings were financial failures, owing to great expense in organisation +and the doubtful factor of the weather, killed this goose before many +golden eggs had been gathered in by the star aviators. Besides, as +height and distance records were broken one after another, it became +less and less necessary to pay for entrance to an aerodrome in order to +see a flight--the thing grew too big for a mere sports ground. + +Long before Rheims and the meeting there, aviation had grown too big for +the chronicling of every individual effort. In that period of the first +days of conquest of the air, so much was done by so many whose names +are now half-forgotten that it is possible only to pick out the great +figures and make brief reference to their achievements and the machines +with which they accomplished so much, pausing to note such epoch-making +events as the London-Manchester flight, Bleriot's Channel crossing, +and the Rheims meeting itself, and then passing on beyond the days of +individual records to the time when the machine began to dominate the +man. This latter because, in the early days, it was heroism to trust +life to the planes that were turned out--the 'Demoiselle' and the +Antoinette machine that Latham used in his attempt to fly the Channel +are good examples of the flimsiness of early types--while in the later +period, that of the war and subsequently, the heroism turned itself in a +different--and nobler-direction. Design became standardised, though +not perfected. The domination of the machine may best be expressed by +contrasting the way in which machines came to be regarded as compared +with the men who flew them: up to 1909, flying enthusiasts talked of +Farman, of Bleriot, of Paulhan, Curtiss, and of other men; later, they +began to talk of the Voisin, the Deperdussin, and even to the Fokker, +the Avro, and the Bristol type. With the standardising of the machine, +the days of the giants came to an end. + + + + +XIII. FIRST FLIERS IN ENGLAND + +Certain experiments made in England by Mr Phillips seem to have come +near robbing the Wright Brothers of the honour of the first flight; +notes made by Colonel J. D. Fullerton on the Phillips flying machine +show that in 1893 the first machine was built with a length of 25 feet, +breadth of 22 feet, and height of 11 feet, the total weight, including a +72 lb. load, being 420 lbs. The machine was fitted with some fifty wood +slats, in place of the single supporting surface of the monoplane or two +superposed surfaces of the biplane, these slats being fixed in a steel +frame so that the whole machine rather resembled a Venetian blind. A +steam engine giving about 9 horse-power provided the motive power for +the six-foot diameter propeller which drove the machine. As it was +not possible to put a passenger in control as pilot, the machine was +attached to a central post by wire guys and run round a circle 100 +feet in diameter, the track consisting of wooden planking 4 feet wide. +Pressure of air under the slats caused the machine to rise some two or +three feet above the track when sufficient velocity had been attained, +and the best trials were made on June 19th 1893, when at a speed of 40 +miles an hour, with a total load of 385 lbs., all the wheels were off +the ground for a distance of 2,000 feet. + +In 1904 a full-sized machine was constructed by Mr Phillips, with a +total weight, including that of the pilot, of 600 lbs. The machine was +designed to lift when it had attained a velocity of 50 feet per +second, the motor fitted giving 22 horse-power. On trial, however, the +longitudinal equilibrium was found to be defective, and a further design +was got out, the third machine being completed in 1907. In this the wood +slats were held in four parallel container frames, the weight of the +machine, excluding the pilot, being 500 lbs. A motor similar to that +used in the 1904 machine was fitted, and the machine was designed to +lift at a velocity of about 30 miles an hour, a seven-foot propeller +doing the driving. Mr Phillips tried out this machine in a field about +400 yards across. 'The machine was started close to the hedge, and rose +from the ground when about 200 yards had been covered. When the machine +touched the ground again, about which there could be no doubt, owing to +the terrific jolting, it did not run many yards. When it came to rest I +was about ten yards from the boundary. Of course, I stopped the engine +before I commenced to descend.'[*] + +[*] Aeronautical Journal, July, 1908. + +S. F. Cody, an American by birth, aroused the attention not only of the +British public, but of the War office and Admiralty as well, as early as +1905 with his man-lifting kites. In that year a height of 1,600 feet was +reached by one of these box-kites, carrying a man, and later in the same +year one Sapper Moreton, of the Balloon Section of the Royal Engineers +(the parent of the Royal Flying Corps) remained for an hour at an +altitude of 2,600 feet. Following on the success of these kites, Cody +constructed an aeroplane which he designated a 'power kite,' which +was in reality a biplane that made the first flight in Great Britain. +Speaking before the Aeronautical Society in 1908, Cody said that 'I have +accomplished one thing that I hoped for very much, that is, to be the +first man to fly in Great Britain.... I made a machine that left the +ground the first time out; not high, possibly five or six inches only. I +might have gone higher if I wished. I made some five flights in all, and +the last flight came to grief.... On the morning of the accident I +went out after adjusting my propellers at 8 feet pitch running at 600 +(revolutions per minute). I think that I flew at about twenty-eight +miles per hour. I had 50 horsepower motor power in the engine. A bunch +of trees, a flat common above these trees, and from this flat there is a +slope goes down... to another clump of trees. Now, these clumps of trees +are a quarter of a mile apart or thereabouts.... I was accused of doing +nothing but jumping with my machine, so I got a bit agitated and went to +fly. + +I went out this morning with an easterly wind, and left the ground at +the bottom of the hill and struck the ground at the top, a distance of +74 yards. That proved beyond a doubt that the machine would fly--it +flew uphill. That was the most talented flight the machine did, in my +opinion. Now, I turned round at the top and started the machine and left +the ground--remember, a ten mile wind was blowing at the time. Then, 60 +yards from where the men let go, the machine went off in this direction +(demonstrating)--I make a line now where I hoped to land--to cut these +trees off at that side and land right off in here. I got here somewhat +excited, and started down and saw these trees right in front of me. I +did not want to smash my head rudder to pieces, so I raised it again and +went up. I got one wing direct over that clump of trees, the right wing +over the trees, the left wing free; the wind, blowing with me, had to +lift over these trees. So I consequently got a false lift on the right +side and no lift on the left side. Being only about 8 feet from the +tree tops, that turned my machine up like that (demonstrating). This +end struck the ground shortly after I had passed the trees. I pulled the +steering handle over as far as I could. Then I faced another bunch of +trees right in front of me. Trying to avoid this second bunch of trees I +turned the rudder, and turned it rather sharp. That side of the machine +struck, and it crumpled up like so much tissue paper, and the machine +spun round and struck the ground that way on, and the framework was +considerably wrecked. Now, I want to advise all aviators not to try +to fly with the wind and to cross over any big clump of earth or any +obstacle of any description unless they go square over the top of it, +because the lift is enormous crossing over anything like that, and in +coming the other way against the wind it would be the same thing when +you arrive at the windward side of the obstacle. That is a point I did +not think of, and had I thought of it I would have been more cautious.' + +This Cody machine was a biplane with about 40 foot span, the wings being +about 7 feet in depth with about 8 feet between upper and lower wing +surfaces. 'Attached to the extremities of the lower planes are two small +horizontal planes or rudders, while a third small vertical plane is +fixed over the centre of the upper plane.' The tail-piece and principal +rudder were fitted behind the main body of the machine, and a horizontal +rudder plane was rigged out in front, on two supporting arms extending +from the centre of the machine. The small end-planes and the vertical +plane were used in conjunction with the main rudder when turning to +right or left, the inner plane being depressed on the turn, and the +outer one correspondingly raised, while the vertical plane, working in +conjunction, assisted in preserving stability. Two two-bladed propellers +were driven by an eight-cylinder 50 horse-power Antoinette motor. With +this machine Cody made his first flights over Laffan's plain, being then +definitely attached to the Balloon Section of the Royal Engineers as +military aviation specialist. + +There were many months of experiment and trial, after the accident which +Cody detailed in the statement given above, and then, on May 14th, 1909, +Cody took the air and made a flight of 1,200 yards with entire success. +Meanwhile A. V. Roe was experimenting at Lea Marshes with a triplane +of rather curious design the pilot having his seat between two sets of +three superposed planes, of which the front planes could be tilted and +twisted while the machine was in motion. He comes but a little way after +Cody in the chronology of early British experimenters, but Cody, a born +inventor, must be regarded as the pioneer of the present century so +far as Britain is concerned. He was neither engineer nor trained +mathematician, but he was a good rule-of-thumb mechanic and a man of +pluck and perseverance; he never strove to fly on an imperfect machine, +but made alteration after alteration in order to find out what was +improvement and what was not, in consequence of which it was said of him +that he was 'always satisfied with his alterations.' + +By July of 1909 he had fitted an 80 horse-power motor to his biplane, +and with this he made a flight of over four miles over Laffan's Plain on +July 21st. By August he was carrying passengers, the first being Colonel +Capper of the R.E. Balloon Section, who flew with Cody for over +two miles, and on September 8th, 1909, he made a world's record +cross-country flight of over forty miles in sixty-six minutes, taking +a course from Laffan's Plain over Farnborough, Rushmoor, and Fleet, +and back to Laffan's Plain. He was one of the competitors in the 1909 +Doncaster Aviation Meeting, and in 1910 he competed at Wolverhampton, +Bournemouth, and Lanark. It was on June 7th, 1910, that he qualified for +his brevet, No. 9, on the Cody biplane. + +He built a machine which embodied all the improvements for which he had +gained experience, in 1911, a biplane with a length of 35 feet and +span of 43 feet, known as the 'Cody cathedral' on account of its +rather cumbrous appearance. With this, in 1911, he won the two Michelin +trophies presented in England, completed the Daily Mail circuit of +Britain, won the Michelin cross-country prize in 1912 and altogether, by +the end of 1912, had covered more than 7,000 miles with the machine. +It was fitted with a 120 horse-power Austro-Daimler engine, and was +characterised by an exceptionally wide range of speed--the great +wingspread gave a slow landing speed. + +A few of his records may be given: in 1910, flying at Laffan's Plain in +his biplane, fitted with a 50-60 horsepower Green engine, on December +31st, he broke the records for distance and time by flying 185 miles, +787 yards, in 4 hours 37 minutes. On October 31st, 1911, he beat this +record by flying for 5 hours 15 minutes, in which period he covered +261 miles 810 yards with a 60 horse-power Green engine fitted to his +biplane. In 1912, competing in the British War office tests of military +aeroplanes, he won the L5,000 offered by the War Office. This was in +competition with no less than twenty-five other machines, among which +were the since-famous Deperdussin, Bristol, Flanders, and Avro types, +as well as the Maurice Farman and Bleriot makes of machine. Cody's +remarkable speed range was demonstrated in these trials, the speeds of +his machine varying between 72.4 and 48.5 miles per hour. The machine +was the only one delivered for the trials by air, and during the three +hours' test imposed on all competitors a maximum height of 5,000 feet +was reached, the first thousand feet being achieved in three and a half +minutes. + +During the summer of 1913 Cody put his energies into the production of +a large hydro-biplane, with which he intended to win the L5,000 prize +offered by the Daily Mail to the first aviator to fly round Britain on +a waterplane. This machine was fitted with landing gear for its tests, +and, while flying it over Laffan's Plain on August 7th, 1913, with Mr W. +H. B. Evans as passenger, Cody met with the accident that cost both +him and his passenger their lives. Aviation lost a great figure by his +death, for his plodding, experimenting, and dogged courage not only won +him the fame that came to a few of the pilots of those days, but also +advanced the cause of flying very considerably and contributed not a +little to the sum of knowledge in regard to design and construction. + +Another figure of the early days was A. V. Roe, who came from marine +engineering to the motor industry and aviation in 1905. In 1906 he went +out to Colorado, getting out drawings for the Davidson helicopter, and +in 1907 having returned to England, he obtained highest award out of 200 +entries in a model aeroplane flying competition. From the design of +this model he built a full-sized machine, and made a first flight on it, +fitted with a 24 horse-power Antoinette engine, in June of 1908 Later, +he fitted a 9 horsepower motor-cycle engine to a triplane of his own +design, and with this made a number of short flights; he got his flying +brevet on a triplane with a motor of 35 horse-power, which, together +with a second triplane, was entered for the Blackpool aviation meeting +of 1910 but was burnt in transport to the meeting. He was responsible +for the building of the first seaplane to rise from English waters, and +may be counted the pioneer of the tractor type of biplane. In 1913 he +built a two-seater tractor biplane with 80 horse-power engine, a machine +which for some considerable time ranked as a leader of design. Together +with E. V. Roe and H. V. Roe, 'A. V.' controlled the Avro works, which +produced some of the most famous training machines of the war period in +a modification of the original 80 horse-power tractor. The first of the +series of Avro tractors to be adopted by the military authorities was +the 1912 biplane, a two-seater fitted with 50 horsepower engine. It was +the first tractor biplane with a closed fuselage to be used for military +work, and became standard for the type. The Avro seaplane, of I 100 +horse-power (a fourteen-cylinder Gnome engine was used) was taken up +by the British Admiralty in 1913. It had a length of 34 feet and a +wing-span of 50 feet, and was of the twin-float type. + +Geoffrey de Havilland, though of later rank, counts high among designers +of British machines. He qualified for his brevet as late as February, +1911, on a biplane of his own construction, and became responsible for +the design of the BE2, the first successful British Government biplane. +On this he made a British height record of 10,500 feet over Salisbury +Plain, in August of 1912, when he took up Major Sykes as passenger. In +the war period he was one of the principal designers of fighting and +reconnaissance machines. + +F. Handley Page, who started in business as an aeroplane builder in +1908, having works at Barking, was one of the principal exponents of +the inherently stable machine, to which he devoted practically all his +experimental work up to the outbreak of war. The experiments were made +with various machines, both of monoplane and biplane type, and of these +one of the best was a two-seater monoplane built in 1911, while a second +was a larger machine, a biplane, built in 1913 and fitted with a 110 +horse-power Anzani engine. The war period brought out the giant biplane +with which the name of Handley Page is most associated, the twin-engined +night-bomber being a familiar feature of the later days of the war; +the four-engined bomber had hardly had a chance of proving itself under +service conditions when the war came to an end. + +Another notable figure of the early period was 'Tommy' Sopwith, who took +his flying brevet at Brooklands in November of 1910, and within four +days made the British duration record of 108 miles in 3 hours 12 +minutes. On December 18th, 1910, he won the Baron de Forrest prize of +L4,000 for the longest flight from England to the Continent, flying +from Eastchurch to Tirlemont, Belgium, in three hours, a distance of 161 +miles. After two years of touring in America, he returned to England and +established a flying school. In 1912 he won the first aerial Derby, and +in 1913 a machine of his design, a tractor biplane, raised the British +height record to 13,000 feet (June 16th, at Brooklands). First as +aviator, and then as designer, Sopwith has done much useful work in +aviation. + +These are but a few, out of a host who contributed to the development of +flying in this country, for, although France may be said to have set +the pace as regards development, Britain was not far behind. French +experimenters received far more Government aid than did the early +British aviators and designers--in the early days the two were +practically synonymous, and there are many stories of the very early +days at Brooklands, where, when funds ran low, the ardent spirits +patched their trousers with aeroplane fabric and went on with their work +with Bohemian cheeriness. Cody, altering and experimenting on Laffan's +Plain, is the greatest figure of them all, but others rank, too, as +giants of the early days, before the war brought full recognition of the +aeroplane's potentialities. + +One of the first men actually to fly in England, Mr J. C. T. +Moore-Brabazon, was a famous figure in the days of exhibition flying, +and won his reputation mainly through being first to fly a circular +mile on a machine designed and built in Great Britain and piloted by a +British subject. Moore-Brabazon's earliest flights were made in France +on a Voisin biplane in 1908, and he brought this machine over to +England, to the Aero Club grounds at Shellness, but soon decided that he +would pilot a British machine instead. An order was placed for a Short +machine, and this, fitted with a 50-60 horse-power Green engine, was +used for the circular mile, which won a prize of L1,000 offered by the +Daily Mail, the feat being accomplished on October 30th, 1909. Five +days later, Moore-Brabazon achieved the longest flight up to that time +accomplished on a British-built machine, covering three and a half +miles. In connection with early flying in England, it is claimed that A. +V. Roe, flying 'Avro B,',' on June 8th, 1908, was actually the first man +to leave the ground, this being at Brooklands, but in point of fact Cody +antedated him. + +No record of early British fliers could be made without the name of C. +S. Rolls, a son of Lord Llangattock, on June 2nd, 1910, he flew across +the English Channel to France, until he was duly observed over French +territory, when he returned to England without alighting. The trip was +made on a Wright biplane, and was the third Channel crossing by air, +Bleriot having made the first, and Jacques de Lesseps the second. Rolls +was first to make the return journey in one trip. He was eventually +killed through the breaking of the tail-plane of his machine in +descending at a flying meeting at Bournemouth. The machine was a Wright +biplane, but the design of the tail-plane--which, by the way, was +an addition to the machine, and was not even sanctioned by the +Wrights--appears to have been carelessly executed, and the plane itself +was faulty in construction. The breakage caused the machine to overturn, +killing Rolls, who was piloting it. + + + + +XIV. RHEIMS, AND AFTER + +The foregoing brief--and necessarily incomplete--survey of the early +British group of fliers has taken us far beyond some of the great events +of the early days of successful flight, and it is necessary to go back +to certain landmarks in the history of aviation, first of which is the +great meeting at Rheims in 1909. Wilbur Wright had come to Europe, +and, flying at Le Mans and Pau--it was on August 8th, 1908, that Wilbur +Wright made the first of his ascents in Europe--had stimulated public +interest in flying in France to a very great degree. Meanwhile, Orville +Wright, flying at Fort Meyer, U.S.A., with Lieutenant Selfridge as a +passenger, sustained an accident which very nearly cost him his life +through the transmission gear of the motor breaking. Selfridge was +killed and Orville Wright was severely injured--it was the first fatal +accident with a Wright machine. + +Orville Wright made a flight of over an hour on September 9th, 1908, and +on December 31st of that year Wilbur flew for 2 hours 19 minutes. Thus, +when the Rheims meeting was organised--more notable because it was the +first of its kind, there were already records waiting to be broken. The +great week opened on August 22nd, there being thirty entrants, including +all the most famous men among the early fliers in France. Bleriot, +fresh from his Channel conquest, was there, together with Henry Farman, +Paulhan, Curtiss, Latham, and the Comte de Lambert, first pupil of the +Wright machine in Europe to achieve a reputation as an aviator. + +'To say that this week marks an epoch in the history of the world is to +state a platitude. Nevertheless, it is worth stating, and for us who +are lucky enough to be at Rheims during this week there is a solid +satisfaction in the idea that we are present at the making of history. +In perhaps only a few years to come the competitions of this week may +look pathetically small and the distances and speeds may appear paltry. +Nevertheless, they are the first of their kind, and that is sufficient.' + +So wrote a newspaper correspondent who was present at the famous +meeting, and his words may stand, being more than mere journalism; for +the great flying week which opened on August 22nd, 1909, ranks as one of +the great landmarks in the history of heavier-than-air flight. The day +before the opening of the meeting a downpour of rain spoilt the flying +ground; Sunday opened with a fairly high wind, and in a lull M. +Guffroy turned out on a crimson R.E.P. monoplane, but the wheels of +his undercarriage stuck in the mud and prevented him from rising in +the quarter of an hour allowed to competitors to get off the ground. +Bleriot, following, succeeded in covering one side of the triangular +course, but then came down through grit in the carburettor. Latham, +following him with thirteen as the number of his machine, experienced +his usual bad luck and came to earth through engine trouble after a very +short flight. Captain Ferber, who, owing to military regulations, always +flew under the name of De Rue, came out next with his Voisin biplane, +but failed to get off the ground; he was followed by Lefebvre on a +Wright biplane, who achieved the success of the morning by rounding the +course--a distance of six and a quarter miles--in nine minutes with a +twenty mile an hour wind blowing. His flight finished the morning. + +Wind and rain kept competitors out of the air until the evening, when +Latham went up, to be followed almost immediately by the Comte de +Lambert. Sommer, Cockburn (the only English competitor), Delagrange, +Fournier, Lefebvre, Bleriot, Bunau-Varilla, Tissandier, Paulhan, +and Ferber turned out after the first two, and the excitement of the +spectators at seeing so many machines in the air at one time provoked +wild cheering. The only accident of the day came when Bleriot damaged +his propeller in colliding with a haycock. + +The main results of the day were that the Comte de Lambert flew 30 +kilometres in 29 minutes 2 seconds; Lefebvre made the ten-kilometre +circle of the track in just a second under 9 minutes, while Tissandier +did it in 9 1/4 minutes, and Paulhan reached a height of 230 feet. Small +as these results seem to us now, and ridiculous as may seem enthusiasm +at the sight of a few machines in the air at the same time, the Rheims +Meeting remains a great event, since it proved definitely to the whole +world that the conquest of the air had been achieved. + +Throughout the week record after record was made and broken. Thus on +the Monday, Lefebvre put up a record for rounding the course and Bleriot +beat it, to be beaten in turn by Glenn Curtiss on his Curtiss-Herring +biplane. On that day, too, Paulhan covered 34 3/4 miles in 1 hour 6 +minutes. On the next day, Paulhan on his Voisin biplane took the air +with Latham, and Fournier followed, only to smash up his machine by +striking an eddy of wind which turned him over several times. On the +Thursday, one of the chief events was Latham's 43 miles accomplished in +1 hour 2 minutes in the morning and his 96.5 miles in 2 hours 13 minutes +in the afternoon, the latter flight only terminated by running out of +petrol. On the Friday, the Colonel Renard French airship, which had +flown over the ground under the pilotage of M. Kapfarer, paid Rheims a +second visit; Latham manoeuvred round the airship on his Antoinette and +finally left it far behind. Henry Farman won the Grand Prix de Champagne +on this day, covering 112 miles in 3 hours, 4 minutes, 56 seconds, +Latham being second with his 96.5 miles flight, and Paulhan third. + +On the Saturday, Glenn Curtiss came to his own, winning the +Gordon-Bennett Cup by covering 20 kilometres in 15 minutes 50.6 seconds. +Bleriot made a good second with 15 minutes 56.2 seconds as his time, +and Latham and Lefebvre were third and fourth. Farman carried off the +passenger prize by carrying two passengers a distance of 6 miles in 10 +minutes 39 seconds. On the last day Delagrange narrowly escaped serious +accident through the bursting of his propeller while in the air, Curtiss +made a new speed record by travelling at the rate of over 50 miles an +hour, and Latham, rising to 500 feet, won the altitude prize. + +These are the cold statistics of the meeting; at this length of time it +is difficult to convey any idea of the enthusiasm of the crowds over +the achievements of the various competitors, while the incidents of +the week, comic and otherwise, are nearly forgotten now even by those +present in this making of history. Latham's great flight on the Thursday +was rendered a breathless episode by a downpour of rain when he had +covered all but a kilometre of the record distance previously achieved +by Paulhan, and there was wild enthusiasm when Latham flew on through +the rain until he had put up a new record and his petrol had run out. +Again, on the Friday afternoon, the Colonel Renard took the air together +with a little French dirigible, Zodiac III; Latham was already in the +air directly over Farman, who was also flying, and three crows which +turned out as rivals to the human aviators received as much cheering for +their appearance as had been accorded to the machines, which doubtless +they could not understand. Frightened by the cheering, the crows tried +to escape from the course, but as they came near the stands, the crowd +rose to cheer again and the crows wheeled away to make a second charge +towards safety, with the same result; the crowd rose and cheered at them +a third and fourth time; between ten and fifteen thousand people stood +on chairs and tables and waved hats and handkerchiefs at three ordinary, +everyday crows. One thoughtful spectator, having thoroughly enjoyed the +funny side of the incident, remarked that the ultimate mastery of the +air lies with the machine that comes nearest to natural flight. This +still remains for the future to settle. + +Farman's world record, which won the Grand Prix de Champagne, was done +with a Gnome Rotary Motor which had only been run on the test bench +and was fitted to his machine four hours before he started on the great +flight. His propeller had never been tested, having only been completed +the night before. The closing laps of that flight, extending as they did +into the growing of the dusk, made a breathlessly eerie experience for +such of the spectators as stayed on to watch--and these were many. Night +came on steadily and Farman covered lap after lap just as steadily, a +buzzing, circling mechanism with something relentless in its isolated +persistency. + +The final day of the meeting provided a further record in the quarter +million spectators who turned up to witness the close of the great week. +Bleriot, turning out in the morning, made a landing in some such fashion +as flooded the carburettor and caused it to catch fire. Bleriot himself +was badly burned, since the petrol tank burst and, in the end, only +the metal parts of the machine were left. Glenn Curtis tried to beat +Bleriot's time for a lap of the course, but failed. In the evening, +Farman and Latham went out and up in great circles, Farman cleaving his +way upward in what at the time counted for a huge machine, on circles +of about a mile diameter. His first round took him level with the top of +the stands, and, in his second, he circled the captive balloon anchored +in the middle of the grounds. After another circle, he came down on a +long glide, when Latham's lean Antoinette monoplane went up in circles +more graceful than those of Farman. 'Swiftly it rose and swept round +close to the balloon, veered round to the hangars, and out over to the +Rheims road. Back it came high over the stands, the people craning their +necks as the shrill cry of the engine drew nearer and nearer behind the +stands. Then of a sudden, the little form appeared away up in the deep +twilight blue vault of the sky, heading straight as an arrow for the +anchored balloon. Over it, and high, high above it went the Antoinette, +seemingly higher by many feet than the Farman machine. Then, wheeling +in a long sweep to the left, Latham steered his machine round past the +stands, where the people, their nerve-tension released on seeing the +machine descending from its perilous height of 500 feet, shouted their +frenzied acclamations to the hero of the meeting. + +'For certainly "Le Tham," as the French call him, was the popular hero. +He always flew high, he always flew well, and his machine was a joy to +the eye, either afar off or at close quarters. The public feeling for +Bleriot is different. Bleriot, in the popular estimation, is the man who +fights against odds, who meets the adverse fates calmly and with good +courage, and to whom good luck comes once in a while as a reward for +much labour and anguish, bodily and mental. Latham is the darling of +the Gods, to whom Fate has only been unkind in the matter of the Channel +flight, and only then because the honour belonged to Bleriot. + +'Next to these two, the public loved most Lefebvre, the joyous, the +gymnastic. Lefebvre was the comedian of the meeting. When things began +to flag, the gay little Lefebvre would trot out to his starting rail, +out at the back of the judge's enclosure opposite the stands, and after +a little twisting of propellers his Wright machine would bounce off the +end of its starting rail and proceed to do the most marvellous tricks +for the benefit of the crowd, wheeling to right and left, darting up and +down, now flying over a troop of the cavalry who kept the plain clear of +people and sending their horses into hysterics, anon making straight +for an unfortunate photographer who would throw himself and his precious +camera flat on the ground to escape annihilation as Lefebvre swept over +him 6 or 7 feet off the ground. Lefebvre was great fun, and when he had +once found that his machine was not fast enough to compete for speed +with the Bleriots, Antoinettes, and Curtiss, he kept to his metier of +amusing people. The promoters of the meeting owe Lefebvre a debt of +gratitude, for he provided just the necessary comic relief.'--(The Aero, +September 7th, 1909.) + +It may be noted, in connection with the fact that Cockburn was the only +English competitor at the meeting, that the Rheims Meeting did more than +anything which had preceded it to waken British interest in aviation. +Previously, heavier-than-air flight in England had been regarded as +a freak business by the great majority, and the very few pioneers who +persevered toward winning England a share in the conquest of the air +came in for as much derision as acclamation. Rheims altered this; it +taught the world in general, and England in particular, that a serious +rival to the dirigible balloon had come to being, and it awakened the +thinking portion of the British public to the fact that the aeroplane +had a future. + +The success of this great meeting brought about a host of imitations +of which only a few deserve bare mention since, unlike the first, they +taught nothing and achieved little. There was the meeting at Boulogne +late in September of 1909, of which the only noteworthy event was +Ferber's death. There was a meeting at Brescia where Curtiss again took +first prize for speed and Rougier put up a world's height record of 645 +feet. The Blackpool meeting followed between 18th and 23rd of October, +1909, forming, with the exception of Doncaster, the first British Flying +Meeting. Chief among the competitors were Henry Farman, who took the +distance prize, Rougier, Paulhan, and Latham, who, by a flight in a high +wind, convinced the British public that the theory that flying was only +possible in a calm was a fallacy. A meeting at Doncaster was practically +simultaneous with the Blackpool week; Delagrange, Le Blon, Sommer, and +Cody were the principal figures in this event. It should be added +that 130 miles was recorded as the total flown at Doncaster, while at +Blackpool only 115 miles were flown. Then there were Juvisy, the first +Parisian meeting, Wolverhampton, and the Comte de Lambert's flight round +the Eiffel Tower at a height estimated at between 1,200 and 1,300 feet. +This may be included in the record of these aerial theatricals, since it +was nothing more. + +Probably wakened to realisation of the possibilities of the aeroplane by +the Rheims Meeting, Germany turned out its first plane late in 1909. +It was known as the Grade monoplane, and was a blend of the Bleriot and +Santos-Dumont machines, with a tail suggestive of the Antoinette type. +The main frame took the form of a single steel tube, at the forward end +of which was rigged a triangular arrangement carrying the pilot's seat +and the landing wheels underneath, with the wing warping wires and stays +above. The sweep of the wings was rather similar to the later Taube +design, though the sweep back was not so pronounced, and the machine was +driven by a four-cylinder, 20 horse-power, air-cooled engine which drove +a two-bladed tractor propeller. In spite of Lilienthal's pioneer +work years before, this was the first power-driven German plane which +actually flew. + +Eleven months after the Rheims meeting came what may be reckoned the +only really notable aviation meeting on English soil, in the form of the +Bournemouth week, July 10th to 16th, 1910. This gathering is noteworthy +mainly in view of the amazing advance which it registered on the Rheims +performances. Thus, in the matter of altitude, Morane reached 4,107 +feet and Drexel came second with 2,490 feet. Audemars on a Demoiselle +monoplane made a flight of 17 miles 1,480 yards in 27 minutes 17.2 +seconds, a great flight for the little Demoiselle. Morane achieved a +speed of 56.64 miles per hour, and Grahame White climbed to 1,000 feet +altitude in 6 minutes 36.8 seconds. Machines carrying the Gnome engine +as power unit took the great bulk of the prizes, and British-built +engines were far behind. + +The Bournemouth Meeting will always be remembered with regret for the +tragedy of C. S. Rolls's death, which took place on the Tuesday, the +second day of the meeting. The first competition of the day was that +for the landing prize; Grahame White, Audemars, and Captain Dickson had +landed with varying luck, and Rolls, following on a Wright machine with +a tail-plane which ought never to have been fitted and was not part of +the Wright design, came down wind after a left-hand turn and turned left +again over the top of the stands in order to land up wind. He began to +dive when just clear of the stands, and had dropped to a height of 40 +feet when he came over the heads of the people against the barriers. +Finding his descent too steep, he pulled back his elevator lever to +bring the nose of the machine up, tipping down the front end of the tail +to present an almost flat surface to the wind. Had all gone well, the +nose of the machine would have been forced up, but the strain on the +tail and its four light supports was too great; the tail collapsed, the +wind pressed down the biplane elevator, and the machine dived vertically +for the remaining 20 feet of the descent, hitting the ground vertically +and crumpling up. Major Kennedy, first to reach the debris, found Rolls +lying with his head doubled under him on the overturned upper main +plane; the lower plane had been flung some few feet away with the engine +and tanks under it. Rolls was instantaneously killed by concussion of +the brain. + +Antithesis to the tragedy was Audemars on his Demoiselle, which was +named 'The Infuriated Grasshopper.' Concerning this, it was recorded +at the time that 'Nothing so excruciatingly funny as the action of +this machine has ever been seen at any aviation ground. The little +two-cylinder engine pops away with a sound like the frantic drawing of +ginger beer corks; the machine scutters along the ground with its tail +well up; then down comes the tail suddenly and seems to slap the ground +while the front jumps up, and all the spectators rock with laughter. The +whole attitude and the jerky action of the machine suggest a grasshopper +in a furious rage, and the impression is intensified when it comes down, +as it did twice on Wednesday, in long grass, burying its head in the +ground in its temper.'--(The Aero, July, 1910.) + +The Lanark Meeting followed in August of the same year, and with the +bare mention of this, the subject of flying meetings may he left +alone, since they became mere matters of show until there came military +competitions such as the Berlin Meeting at the end of August, 1910, +and the British War office Trials on Salisbury Plain, when Cody won his +greatest triumphs. The Berlin meeting proved that, from the time of the +construction of the first successful German machine mentioned above, to +the date of the meeting, a good number of German aviators had qualified +for flight, but principally on Wright and Antoinette machines, though +by that time the Aviatik and Dorner German makes had taken the air. The +British War office Trials deserve separate and longer mention. + +In 1910 in spite of official discouragement, Captain Dickson proved the +value of the aeroplane for scouting purposes by observing movements +of troops during the Military Manoeuvres on Salisbury Plain. Lieut. +Lancelot Gibbs and Robert Loraine, the actor-aviator, also made flights +over the manoeuvre area, locating troops and in a way anticipating the +formation and work of the Royal Flying Corps by a usefulness which could +not be officially recognised. + + + + +XV. THE CHANNEL CROSSING + +It may be said that Louis Bleriot was responsible for the second great +landmark in the history of successful flight. The day when the brothers +Wright succeeded in accomplishing power-driven flight ranks as the first +of these landmarks. Ader may or may not have left the ground, but the +wreckage of his 'Avion' at the end of his experiment places his doubtful +success in a different category from that of the brothers Wright and +leaves them the first definite conquerors, just as Bleriot ranks as +first definite conqueror of the English Channel by air. + +In a way, Louis Bleriot ranks before Farman in point of time; his +first flapping-wing model was built as early as 1900, and Voisin flew a +biplane glider of his on the Seine in the very early experimental days. +Bleriot's first four machines were biplanes, and his fifth, a monoplane, +was wrecked almost immediately after its construction. Bleriot had +studied Langley's work to a certain extent, and his sixth construction +was a double monoplane based on the Langley principle. A month after +he had wrecked this without damaging himself--for Bleriot had as many +miraculous escapes as any of the other fliers-he brought out number +seven, a fairly average monoplane. It was in December of 1907 after a +series of flights that he wrecked this machine, and on its successor, in +July of 1908, he made a flight of over 8 minutes. Sundry flights, more +or less successful, including the first cross-country flight from Toury +to Artenay, kept him busy up to the beginning of November, 1908, when +the wreckage in a fog of the machine he was flying sent him to the +building of 'number eleven,' the famous cross-channel aeroplane. + +Number eleven was shown at the French Aero Show in the Grand Palais +and was given its first trials on the 18th January, 1909. It was first +fitted with a R.E.P. motor and had a lifting area of 120 square feet, +which was later increased to 150 square feet. The framework was of oak +and poplar spliced and reinforced with piano wire; the weight of the +machine was 47 lbs. and the undercarriage weight a further 60 lbs., this +consisting of rubber cord shock absorbers mounted on two wheels. The +R.E.P. motor was found unsatisfactory, and a three-cylinder Anzani +of 105 mm. bore and 120 mm. stroke replaced it. An accident seriously +damaged the machine on June 2nd, but Bleriot repaired it and tested it +at Issy, where between June 19th and June 23rd he accomplished flights +of 8, 12, 15, 16, and 36 minutes. On July 4th he made a 50-minute flight +and on the 13th flew from Etampes to Chevilly. + +A few further details of construction may be given: the wings themselves +and an elevator at the tail controlled the rate of ascent and descent, +while a rudder was also fitted at the tail. The steering lever, +working on a universally jointed shaft--forerunner of the modern +joystick--controlled both the rudder and the wings, while a pedal +actuated the elevator. The engine drove a two-bladed tractor screw of 6 +feet 7 inches diameter, and the angle of incidence of the wings was 20 +degrees. Timed at Issy, the speed of the machine was given as 36 miles +an hour, and as Bleriot accomplished the Channel flight of 20 miles in +37 minutes, he probably had a slight following wind. + +The Daily Mail had offered a prize of L1,000 for the first Cross-Channel +flight, and Hubert Latham set his mind on winning it. He put up a +shelter on the French coast at Sangatte, half-way between Calais and +Cape Blanc Nez. From here he made his first attempt to fly to England +on Monday the 19th of July. He soared to a fair height, circling, and +reached an estimated height of about 900 feet as he came over the water +with every appearance of capturing the Cross-Channel prize. The luck +which dogged his career throughout was against him, for, after he had +covered some 8 miles, his engine stopped and he came down to the water +in a series of long glides. It was discovered afterward that a small +piece of wire had worked its way into a vital part of the engine to rob +Latham of the honour he coveted. The tug that came to his rescue found +him seated on the fuselage of his Antoinette, smoking a cigarette and +waiting for a boat to take him to the tug. It may be remarked that +Latham merely assumed his Antoinette would float in case he failed to +make the English coast; he had no actual proof. + +Bleriot immediately entered his machine for the prize and took up his +quarters at Barraques. On Sunday, July 25th, 1909, shortly after 4 a.m., +Bleriot had his machine taken out from its shelter and prepared for +flight. He had been recently injured in a petrol explosion and hobbled +out on crutches to make his cross-Channel attempt; he made two great +circles in the air to try the machine, and then alighted. 'In ten +minutes I start for England,' he declared, and at 4.35 the motor was +started up. After a run of 100 yards, the machine rose in the air and +got a height of about 100 feet over the land, then wheeling sharply +seaward and heading for Dover. + +Bleriot had no means of telling direction, and any change of wind might +have driven him out over the North Sea, to be lost, as were Cecil Grace +and Hamel later on. Luck was with him, however, and at 5.12 a.m. of that +July Sunday, he made his landing in the North Fall meadow, just behind +Dover Castle. Twenty minutes out from the French coast, he lost sight of +the destroyer which was patrolling the Channel, and at the same time +he was out of sight of land without compass or any other means of +ascertaining his direction. Sighting the English coast, he found that +he had gone too far to the east, for the wind increased in strength +throughout the flight, this to such an extent as almost to turn the +machine round when he came over English soil. Profiting by Latham's +experience, Bleriot had fitted an inflated rubber cylinder a foot in +diameter by 5 feet in length along the middle of his fuselage, to render +floating a certainty in case he had to alight on the water. + +Latham in his camp at Sangatte had been allowed to sleep through the +calm of the early morning through a mistake on the part of a friend, and +when his machine was turned out--in order that he might emulate Bleriot, +although he no longer hoped to make the first flight, it took so long +to get the machine ready and dragged up to its starting-point that there +was a 25 mile an hour wind by the time everything was in readiness. +Latham was anxious to make the start in spite of the wind, but the +Directors of the Antoinette Company refused permission. It was not until +two days later that the weather again became favourable, and then with a +fresh machine, since the one on which he made his first attempt had +been very badly damaged in being towed ashore, he made a circular trial +flight of about 5 miles. In landing from this, a side gust of wind drove +the nose of the machine against a small hillock, damaging both propeller +blades and chassis, and it was not until evening that the damage was +repaired. + +French torpedo boats were set to mark the route, and Latham set out on +his second attempt at six o'clock. Flying at a height of 200 feet, he +headed over the torpedo boats for Dover and seemed certain of making the +English coast, but a mile and a half out from Dover his engine failed +him again, and he dropped to the water to be picked up by the steam +pinnace of an English warship and put aboard the French destroyer +Escopette. + +There is little to choose between the two aviators for courage in +attempting what would have been considered a foolhardy feat a year or +two before. Bleriot's state, with an abscess in the burnt foot which had +to control the elevator of his machine, renders his success all the +more remarkable. His machine was exhibited in London for a time, and +was afterwards placed in the Conservatoire des Arts et Metiers, while a +memorial in stone, copying his monoplane in form, was let into the turf +at the point where he landed. + +The second Channel crossing was not made until 1910, a year of new +records. The altitude record had been lifted to over 10,000 feet, the +duration record to 8 hours 12 minutes, and the distance for a single +flight to 365 miles, while a speed of over 65 miles an hour had been +achieved, when Jacques de Lesseps, son of the famous engineer of Suez +Canal and Panama fame, crossed from France to England on a Bleriot +monoplane. By this time flying had dropped so far from the marvellous +that this second conquest of the Channel aroused but slight public +interest in comparison with Bleriot's feat. + +The total weight of Bleriot's machine in Cross Channel trim was 660 +lbs., including the pilot and sufficient petrol for a three hours' run; +at a speed of 37 miles an hour, it was capable of carrying about 5 +lbs. per square foot of lifting surface. It was the three-cylinder 25 +horse-power Anzani motor which drove the machine for the flight. Shortly +after the flight had been accomplished, it was announced that the +Bleriot firm would construct similar machines for sale at L400 apiece--a +good commentary on the prices of those days. + +On June the 2nd, 1910, the third Channel crossing was made by C. S. +Rolls, who flew from Dover, got himself officially observed over French +soil at Barraques, and then flew back without landing. He was the first +to cross from the British side of the Channel and also was the first +aviator who made the double journey. By that time, however, distance +flights had so far increased as to reduce the value of the feat, and +thenceforth the Channel crossing was no exceptional matter. The honour, +second only to that of the Wright Brothers, remains with Bleriot. + + + + +XVI. LONDON TO MANCHESTER + +The last of the great contests to arouse public enthusiasm was the +London to Manchester Flight of 1910. As far back as 1906, the Daily +Mail had offered a prize of L10,000 to the first aviator who should +accomplish this journey, and, for a long time, the offer was regarded as +a perfectly safe one for any person or paper to make--it brought forth +far more ridicule than belief. Punch offered a similar sum to the first +man who should swim the Atlantic and also for the first flight to Mars +and back within a week, but in the spring of 1910 Claude Grahame White +and Paulhan, the famous French pilot, entered for the 183 mile run on +which the prize depended. Both these competitors flew the Farman biplane +with the 50 horse-power Gnome motor as propulsive power. Grahame White +surveyed the ground along the route, and the L. & N. W. Railway Company, +at his request, whitewashed the sleepers for 100 yards on the north side +of all junctions to give him his direction on the course. The machine +was run out on to the starting ground at Park Royal and set going at +5.19 a.m. on April 23rd. After a run of 100 yards, the machine went up +over Wormwood Scrubs on its journey to Normandy, near Hillmorten, which +was the first arranged stopping place en route; Grahame White landed +here in good trim at 7.20 a.m., having covered 75 miles and made a +world's record cross country flight. At 8.15 he set off again to come +down at Whittington, four miles short of Lichfield, at about 9.20, with +his machine in good order except for a cracked landing skid. Twice, on +this second stage of the journey, he had been caught by gusts of wind +which turned the machine fully round toward London, and, when over a +wood near Tamworth, the engine stopped through a defect in the balance +springs of two exhaust valves; although it started up again after a 100 +foot glide, it did not give enough power to give him safety in the gale +he was facing. The rising wind kept him on the ground throughout the +day, and, though he hoped for better weather, the gale kept up until +the Sunday evening. The men in charge of the machine during its halt had +attempted to hold the machine down instead of anchoring it with stakes +and ropes, and, in consequence of this, the wind blew the machine over +on its back, breaking the upper planes and the tail. Grahame White had +to return to London, while the damaged machine was prepared for a second +flight. The conditions of the competition enacted that the full journey +should be completed within 24 hours, which made return to the starting +ground inevitable. + +Louis Paulhan, who had just arrived with his Farman machine, immediately +got it unpacked and put together in order to be ready to make his +attempt for the prize as soon as the weather conditions should admit. +At 5.31 p.m., on April 27th, he went up from Hendon and had travelled +50 miles when Grahame White, informed of his rival's start, set out to +overtake him. Before nightfall Paulhan landed at Lichfield, 117 miles +from London, while Grahame White had to come down at Roden, only 60 +miles out. The English aviator's chance was not so small as it seemed, +for, as Latham had found in his cross-Channel attempts, engine failure +was more the rule than the exception, and a very little thing might +reverse the relative positions. + +A special train accompanied Paulhan along the North-Western route, +conveying Madame Paulhan, Henry Farman, and the mechanics who fitted the +Farman biplane together. Paulhan himself, who had flown at a height of +1,000 feet, spent the night at Lichfield, starting again at 4.9 a.m. +On the 28th, passing Stafford at 4.45, Crewe at 5.20, and landing at +Burnage, near Didsbury, at 5.32, having had a clean run. + +Meanwhile, Grahame White had made a most heroic attempt to beat his +rival. An hour before dawn on the 28th, he went to the small field in +which his machine had landed, and in the darkness managed to make an +ascent from ground which made starting difficult even in daylight. +Purely by instinct and his recollection of the aspect of things the +night before, he had to clear telegraph wires and a railway bridge, +neither of which he could possibly see at that hour. His engine, too, +was faltering, and it was obvious to those who witnessed his start that +its note was far from perfect. + +At 3.50 he was over Nuneaton and making good progress; between +Atherstone and Lichfield the wind caught him and the engine failed more +and more, until at 4.13 in the morning he was forced to come to earth, +having covered 6 miles less distance than in his first attempt. It was +purely a case of engine failure, for, with full power, he would have +passed over Paulhan just as the latter was preparing for the restart. +Taking into consideration the two machines, there is little doubt that +Grahame White showed the greater flying skill, although he lost the +prize. After landing and hearing of Paulhan's victory, on which he wired +congratulations, he made up his mind to fly to Manchester within the +24 hours. He started at 5 o'clock in the afternoon from Polesworth, his +landing place, but was forced to land at 5.30 at Whittington, where +he had landed on the previous Saturday. The wind, which had forced his +descent, fell again and permitted of starting once more; on this third +stage he reached Lichfield, only to make his final landing at 7.15 p.m., +near the Trent Valley station. The defective running of the Gnome engine +prevented his completing the course, and his Farman machine had to be +brought back to London by rail. + +The presentation of the prize to Paulhan was made the occasion for the +announcement of a further competition, consisting of a 1,000 mile flight +round a part of Great Britain. In this, nineteen competitors started, +and only four finished; the end of the race was a great fight between +Beaumont and Vedrines, both of whom scorned weather conditions in their +determination to win. Beaumont made the distance in a flying time of +22 hours 28 minutes 19 seconds, and Vedrines covered the journey in +a little over 23 1/2 hours. Valentine came third on a Deperdussin +monoplane and S. F. Cody on his Cathedral biplane was fourth. This was +in 1911, and by that time heavier-than-air flight had so far advanced +that some pilots had had war experience in the Italian campaign in +Tripoli, while long cross-country flights were an everyday event, and +bad weather no longer counted. + + + + +XVII. A SUMMARY, TO 1911 + +There is so much overlapping in the crowded story of the first years +of successful power-driven flight that at this point it is advisable to +make a concise chronological survey of the chief events of the period of +early development, although much of this is of necessity recapitulation. +The story begins, of course, with Orville Wright's first flight of 852 +feet at Kitty Hawk on December 19th, 1903. The next event of note was +Wright's flight of 11.12 miles in 18 minutes 9 seconds at Dayton, +Ohio, on September 26th, 1905, this being the first officially recorded +flight. On October 4th of the same year, Wright flew 20.75 miles in 33 +minutes 17 seconds, this being the first flight of over 20 miles ever +made. Then on September 14th 1906, Alberto Santos-Dumont made a +flight of eight seconds on the second heavier-than-air machine he had +constructed. It was a big box-kite-like machine; this was the second +power-driven aeroplane in Europe to fly, for although Santos-Dumont's +first machine produced in 1905 was reckoned an unsuccessful design, it +had actually got off the ground for brief periods. Louis Bleriot came +into the ring on April 5th, 1907, with a first flight of 6 seconds on a +Bleriot monoplane, his eighth but first successful construction. + +Henry Farman made his first appearance in the history of aviation with a +flight of 935 feet on a Voisin biplane on October 15th 1907. On October +25th, in a flight of 2,530 feet, he made the first recorded turn in +the air, and on March 29th, 1908, carrying Leon Delagrange on a Voisin +biplane, he made the first passenger flight. On April 10th of this +year, Delagrange, in flying 1 1/2 miles, made the first flight in Europe +exceeding a mile in distance. He improved on this by flying 10 1/2 miles +at Milan on June 22nd, while on July 8th, at Turin, he took up Madame +Peltier, the first woman to make an aeroplane flight. + +Wilbur Wright, coming over to Europe, made his first appearance on the +Continent with a flight of 1 3/4 minutes at Hunaudieres, France, on +August 8th, 1908. On September 6th, at Chalons, he flew for 1 hour 4 +minutes 26 seconds with a passenger, this being the first flight in +which an hour in the air was exceeded with a passenger on board. + +On September 12th 1908, Orville Wright, flying at Fort Meyer, U.S.A., +with Lieut. Selfridge as passenger, crashed his machine, suffering +severe injuries, while Selfridge was killed. This was the first +aeroplane fatality. On October 30th, 1908, Farman made the first +cross-country flight, covering the distance of 17 miles between Bouy and +Rheims. The next day, Louis Bleriot, in flying from Toury to Artenay, +made two landings en route, this being the first cross-country flight +with landings. On the last day of the year, Wilbur Wright won the +Michelin Cup at Auvours with a flight of 90 miles, which, lasting 2 +hours 20 minutes 23 seconds, exceeded 2 hours in the air for the first +time. + +On January 2nd, 1909, S. F. Cody opened the New Year by making the first +observed flight at Farnborough on a British Army aeroplane. It was not +until July 18th of 1909 that the first European height record deserving +of mention was put up by Paulhan, who achieved a height of 450 feet on a +Voisin biplane. This preceded Latham's first attempt to fly the Channel +by two days, and five days later, on the 25th of the month, Bleriot made +the first Channel crossing. The Rheims Meeting followed on August 22nd, +and it was a great day for aviation when nine machines were seen in +the air at once. It was here that Farman, with a 118 mile flight, +first exceeded the hundred miles, and Latham raised the height record +officially to 500 feet, though actually he claimed to have reached 1,200 +feet. On September 8th, Cody, flying from Aldershot, made a 40 mile +journey, setting up a new cross-country record. On October 19th the +Comte de Lambert flew from Juvisy to Paris, rounded the Eiffel Tower and +flew back. J. T. C. Moore-Brabazon made the first circular mile flight +by a British aviator on an all-British machine in Great Britain, on +October 30th, flying a Short biplane with a Green engine. Paulhan, +flying at Brooklands on November 2nd, accomplished 96 miles in 2 hours +48 minutes, creating a British distance record; on the following +day, Henry Farman made a flight of 150 miles in 4 hours 22 minutes +at Mourmelon, and on the 5th of the month, Paulhan, flying a Farman +biplane, made a world's height record of 977 feet. This, however, was +not to stand long, for Latham got up to 1,560 feet on an Antoinette at +Mourmelon on December 1st. December 31st witnessed the first flight +in Ireland, made by H. Ferguson on a monoplane which he himself had +constructed at Downshire Park, Lisburn. + +These, thus briefly summarised, are the principal events up to the end +of 1909. 1910 opened with tragedy, for on January 4th Leon Delagrange, +one of the greatest pilots of his time, was killed while flying at +Pau. The machine was the Bleriot XI which Delagrange had used at the +Doncaster meeting, and to which Delagrange had fitted a 50 horse-power +Gnome engine, increasing the speed of the machine from its original +30 to 45 miles per hour. With the Rotary Gnome engine there was of +necessity a certain gyroscopic effect, the strain of which proved too +much for the machine. Delagrange had come to assist in the inauguration +of the Croix d'Hins aerodrome, and had twice lapped the course at a +height of about 60 feet. At the beginning of the third lap, the strain +of the Gnome engine became too great for the machine; one wing collapsed +as if the stay wires had broken, and the whole machine turned over and +fell, killing Delagrange. + +On January 7th Latham, flying at Mourmelon, first made the vertical +kilometre and dedicated the record to Delagrange, this being the day of +his friend's funeral. The record was thoroughly authenticated by a large +registering barometer which Latham carried, certified by the officials +of the French Aero Club. Three days later Paulhan, who was at Los +Angeles, California, raised the height record to 4,146 feet. + +On January 25th the Brussels Exhibition opened, when the Antoinette +monoplane, the Gaffaux and Hanriot monoplanes, together with the +d'Hespel aeroplane, were shown; there were also the dirigible Belgica +and a number of interesting aero engines, including a German airship +engine and a four-cylinder 50 horse-power Miesse, this last air-cooled +by means of 22 fans driving a current of air through air jackets +surrounding fluted cylinders. + +On April 2nd Hubert Le Blon, flying a Bleriot with an Anzani engine, +was killed while flying over the water. His machine was flying quite +steadily, when it suddenly heeled over and came down sideways into the +sea; the motor continued running for some seconds and the whole machine +was drawn under water. When boats reached the spot, Le Blon was found +lying back in the driving seat floating just below the surface. He had +done good flying at Doncaster, and at Heliopolis had broken the world's +speed records for 5 and 10 kilometres. The accident was attributed to +fracture of one of the wing stay wires when running into a gust of wind. + +The next notable event was Paulhan's London-Manchester flight, of which +full details have already been given. In May Captain Bertram Dickson, +flying at the Tours meeting, beat all the Continental fliers whom he +encountered, including Chavez, the Peruvian, who later made the +first crossing of the Alps. Dickson was the first British winner of +international aviation prizes. + +C. S. Rolls, of whom full details have already been given, was killed at +Bournemouth on July 12th, being the first British aviator of note to be +killed in an aeroplane accident. His return trip across the Channel had +taken place on June 2nd. Chavez, who was rapidly leaping into fame, as +a pilot, raised the British height record to 5,750 feet while flying at +Blackpool on August 3rd. On the 11th of that month, Armstrong Drexel, +flying a Bleriot, made a world's height record of 6,745 feet. + +It was in 1910 that the British War office first began fully to realise +that there might be military possibilities in heavier-than-air flying. +C. S. Rolls had placed a Wright biplane at the disposal of the military +authorities, and Cody, as already recorded, had been experimenting with +a biplane type of his own for some long period. Such development as was +achieved was mainly due to the enterprise and energy of Colonel J. E. +Capper, C.B., appointed to the superintendency of the Balloon Factory +and Balloon School at Farnborough in 1906. Colonel Capper's retirement +in 1910 brought (then) Mr Mervyn O'Gorman to command, and by that time +the series of successes of the Cody biplane, together with the proved +efficiency of the aeroplane in various civilian meetings, had convinced +the British military authorities that the mastery of the air did not lie +altogether with dirigible airships, and it may be said that in 1910 the +British War office first began seriously to consider the possibilities +of the aeroplane, though two years more were to elapse before the +formation of the Royal Flying Corps marked full realisation of its +value. + +A triumph and a tragedy were combined in September of 1910. On the 23rd +of the month, Georges Chavez set out to fly across the Alps on a Bleriot +monoplane. Prizes had been offered by the Milan Aviation Committee for +a flight from Brigue in Switzerland over the Simplon Pass to Milan, +a distance of 94 miles with a minimum height of 6,600 feet above sea +level. Chavez started at 1.30 p.m. On the 23rd, and 41 minutes later he +reached Domodossola, 25 miles distant. Here he descended, numbed with +the cold of the journey; it was said that the wings of his machine +collapsed when about 30 feet from the ground, but however this may +have been, he smashed the machine on landing, and broke both legs, in +addition to sustaining other serious injuries. He lay in hospital until +the 27th September, when he died, having given his life to the conquest +of the Alps. His death in the moment of success was as great a tragedy +as were those of Pilcher and Lilienthal. + +The day after Chavez's death, Maurice Tabuteau flew across the Pyrenees, +landing in the square at Biarritz. On December 30th, Tabuteau made a +flight of 365 miles in 7 hours 48 minutes. Farman, on December 18th, had +flown for over 8 hours, but his total distance was only 282 miles. The +autumn of this year was also noteworthy for the fact that aeroplanes +were first successfully used in the French Military Manoeuvres. The +British War Office, by the end of the year, had bought two machines, a +military type Farman and a Paulhan, ignoring British experimenters and +aeroplane builders of proved reliability. These machines, added to an +old Bleriot two-seater, appear to have constituted the British aeroplane +fleet of the period. + +There were by this time three main centres of aviation in England, apart +from Cody, alone on Laffan's Plain. These three were Brooklands, Hendon, +and the Isle of Sheppey, and of the three Brooklands was chief. +Here such men as Graham Gilmour, Rippen, Leake, Wickham, and Thomas +persistently experimented. Hendon had its own little group, and +Shellbeach, Isle of Sheppey, held such giants of those days as C. S. +Rolls and Moore Brabazon, together with Cecil Grace and Rawlinson. One +or other, and sometimes all of these were deserted on the occasion of +some meeting or other, but they were the points where the spade work was +done, Brooklands taking chief place. 'If you want the early history +of flying in England, it is there,' one of the early school remarked, +pointing over toward Brooklands course. + +1911 inaugurated a new series of records of varying character. On +the 17th January, E. B. Ely, an American, flew from the shore of San +Francisco to the U.S. cruiser Pennsylvania, landing on the cruiser, +and then flew back to the shore. The British military designing of +aeroplanes had been taken up at Farnborough by G. H. de Havilland, who +by the end of January was flying a machine of his own design, when he +narrowly escaped becoming a casualty through collision with an obstacle +on the ground, which swept the undercarriage from his machine. + +A list of certified pilots of the countries of the world was issued +early in 1911, showing certificates granted up to the end of 1910. +France led the way easily with 353 pilots; England came next with 57, +and Germany next with 46; Italy owned 32, Belgium 27, America 26, and +Austria 19; Holland and Switzerland had 6 aviators apiece, while Denmark +followed with 3, Spain with 2, and Sweden with 1. The first certificate +in England was that of J. T. C. Moore-Brabazon, while Louis Bleriot was +first on the French list and Glenn Curtiss, first holder of an American +certificate, also held the second French brevet. + +On the 7th March, Eugene Renaux won the Michelin Grand Prize by flying +from the French Aero Club ground at St Cloud and landing on the Puy de +Dome. The landing, which was one of the conditions of the prize, was +one of the most dangerous conditions ever attached to a competition; +it involved dropping on to a little plateau 150 yards square, with +a possibility of either smashing the machine against the face of the +mountain, or diving over the edge of the plateau into the gulf beneath. +The length of the journey was slightly over 200 miles and the height of +the landing point 1,465 metres, or roughly 4,500 feet above sea-level. +Renaux carried a passenger, Doctor Senoucque, a member of Charcot's +South Polar Expedition. + +The 1911 Aero Exhibition held at Olympia bore witness to the enormous +strides made in construction, more especially by British designers, +between 1908 and the opening of the Show. The Bristol Firm showed three +machines, including a military biplane, and the first British built +biplane with tractor screw. The Cody biplane, with its enormous size +rendering it a prominent feature of the show, was exhibited. Its +designer anticipated later engines by expressing his desire for a motor +of 150 horse-power, which in his opinion was necessary to get the best +results from the machine. The then famous Dunne monoplane was exhibited +at this show, its planes being V-shaped in plan, with apex leading. It +embodied the results of very lengthy experiments carried out both with +gliders and power-driven machines by Colonel Capper, Lieut. Gibbs, +and Lieut. Dunne, and constituted the longest step so far taken in the +direction of inherent stability. + +Such forerunners of the notable planes of the war period as the Martin +Handasyde, the Nieuport, Sopwith, Bristol, and Farman machines, were +features of the show; the Handley-Page monoplane, with a span of 32 +feet over all, a length of 22 feet, and a weight of 422 lbs., bore no +relation at all to the twin-engined giant which later made this firm +famous. In the matter of engines, the principal survivals to the present +day, of which this show held specimens, were the Gnome, Green, Renault +air-cooled, Mercedes four-cylinder dirigible engine of 115 horse-power, +and 120 horsepower Wolseley of eight cylinders for use with dirigibles. + +On April 12th, of 1911, Paprier, instructor at the Bleriot school at +Hendon, made the first non-stop flight between London and Paris. He left +the aerodrome at 1.37 p.m., and arrived at Issy-les-Moulineaux at 5.33 +p.m., thus travelling 250 miles in a little under 4 hours. He followed +the railway route practically throughout, crossing from Dover to nearly +opposite Calais, keeping along the coast to Boulogne, and then following +the Nord Railway to Amiens, Beauvais, and finally Paris. + +In May, the Paris-Madrid race took place; Vedrines, flying a Morane +biplane, carried off the prize by first completing the distance of 732 +miles. The Paris-Rome race of 916 miles was won in the same month by +Beaumont, flying a Bleriot monoplane. In July, Koenig won the German +National Circuit race of 1,168 miles on an Albatross biplane. This was +practically simultaneous with the Circuit of Britain won by Beaumont, +who covered 1,010 miles on a Bleriot monoplane, having already won +the Paris-Brussels-London-Paris Circuit of 1,080 miles, this also on +a Bleriot. It was in August that a new world's height record of 11,152 +feet was set up by Captain Felix at Etampes, while on the 7th of the +month Renaux flew nearly 600 miles on a Maurice Farman machine in 12 +hours. Cody and Valentine were keeping interest alive in the Circuit of +Britain race, although this had long been won, by determinedly plodding +on at finishing the course. + +On September 9th, the first aerial post was tried between Hendon and +Windsor, as an experiment in sending mails by aeroplane. Gustave Hamel +flew from Hendon to Windsor and back in a strong wind. A few days +later, Hamel went on strike, refusing to carry further mails unless the +promoters of the Aerial Postal Service agreed to pay compensation to +Hubert, who fractured both his legs on the 11th of the month while +engaged in aero postal work. The strike ended on September 25th, when +Hamel resumed mail-carrying in consequence of the capitulation of the +Postmaster-General, who agreed to set aside L500 as compensation to +Hubert. + +September also witnessed the completion in America of a flight across +the Continent, a distance of 2,600 miles. The only competitor who +completed the full distance was C. P. Rogers, who was disqualified +through failing to comply with the time limit. Rogers needed so many +replacements to his machine on the journey that, expressing it in +American fashion, he arrived with practically a dfferent aeroplane from +that with which he started. + +With regard to the aerial postal service, analysis of the matter carried +and the cost of the service seemed to show that with a special charge of +one shilling for letters and sixpence for post cards, the revenue just +balanced the expenditure. It was not possible to keep to the time-table +as, although the trials were made in the most favourable season of the +year, aviation was not sufficiently advanced to admit of facing all +weathers and complying with time-table regulations. + +French military aeroplane trials took place at Rheims in October, the +noteworthy machines being Antoinette, Farman, Nieuport, and Deperdussin. +The tests showed the Nieuport monoplane with Gnome motor as first in +position; the Breguet biplane was second, and the Deperdussin monoplanes +third. The first five machines in order of merit were all engined with +the Gnome motor. + +The records quoted for 1911 form the best evidence that can be given of +advance in design and performance during the year. It will be seen that +the days of the giants were over; design was becoming more and more +standardised and aviation not so much a matter of individual courage and +even daring, as of the reliability of the machine and its engine. +This was the first year in which the twin-engined aeroplane made its +appearance, and it was the year, too, in which flying may be said to +have grown so common that the 'meetings' which began with Rheims were +hardly worth holding, owing to the fact that increase in height and +distance flown rendered it no longer necessary for a would-be spectator +of a flight to pay half a crown and enter an enclosure. Henceforth, +flying as a spectacle was very little to be considered; its commercial +aspects were talked of, and to a very slight degree exploited, but, more +and more, the fact that the aeroplane was primarily an engine of war, +and the growing German menace against the peace of the world combined +to point the way of speediest development, and the arrangements for the +British Military Trials to be held in August, 1912, showed that even +the British War office was waking up to the potentialities of this new +engine of war. + + + + +XVIII. A SUMMARY, TO 1914 + +Consideration of the events in the years immediately preceding the War +must be limited to as brief a summary as possible, this not only because +the full history of flying achievements is beyond the compass of any +single book, but also because, viewing the matter in perspective, the +years 1903-1911 show up as far more important as regards both design and +performance. From 1912 to August of 1914, the development of aeronautics +was hindered by the fact that it had not progressed far enough to form +a real commercial asset in any country. The meetings which drew vast +concourses of people to such places as Rheims and Bournemouth may have +been financial successes at first, but, as flying grew more common and +distances and heights extended, a great many people found it other than +worth while to pay for admission to an aerodrome. The business of taking +up passengers for pleasure flights was not financially successful, and, +although schemes for commercial routes were talked of, the aeroplane was +not sufficiently advanced to warrant the investment of hard cash in +any of these projects. There was a deadlock; further development +was necessary in order to secure financial aid, and at the same time +financial aid was necessary in order to secure further development. +Consequently, neither was forthcoming. + +This is viewing the matter in a broad and general sense; there were +firms, especially in France, but also in England and America, which +looked confidently for the great days of flying to arrive, and regarded +their sunk capital as investment which would eventually bring its due +return. But when one looks back on those years, the firms in question +stand out as exceptions to the general run of people, who regarded +aeronautics as something extremely scientific, exceedingly dangerous, +and very expensive. The very fame that was attained by such pilots as +became casualties conduced to the advertisement of every death, and the +dangers attendant on the use of heavier-than-air machines became greatly +exaggerated; considering the matter as one of number of miles flown, +even in the early days, flying exacted no more toll in human life than +did railways or road motors in the early stages of their development. +But to take one instance, when C. S. Rolls was killed at Bournemouth by +reason of a faulty tail-plane, the fact was shouted to the whole world +with almost as much vehemence as characterised the announcement of the +Titanic sinking in mid-Atlantic. + +Even in 1911 the deadlock was apparent; meetings were falling off in +attendance, and consequently in financial benefit to the promoters; +there remained, however, the knowledge--for it was proved past +question--that the aeroplane in its then stage of development was a +necessity to every army of the world. France had shown this by the more +than interest taken by the French Government in what had developed into +an Air Section of the French army; Germany, of course, was hypnotised by +Count Zeppelin and his dirigibles, to say nothing of the Parsevals which +had been proved useful military accessories; in spite of this, it was +realised in Germany that the aeroplane also had its place in military +affairs. England came into the field with the military aeroplane trials +of August 1st to 15th, 1912, barely two months after the founding of the +Royal Flying Corps. + +When the R.F.C. was founded--and in fact up to two years after its +founding--in no country were the full military potentialities of the +aeroplane realised; it was regarded as an accessory to cavalry for +scouting more than as an independent arm; the possibilities of bombing +were very vaguely considered, and the fact that it might be possible to +shoot from an aeroplane was hardly considered at all. The conditions of +the British Military Trials of 1912 gave to the War office the option +of purchasing for L1,000 any machine that might be awarded a prize. +Machines were required, among other things, to carry a useful load of +350 lbs. in addition to equipment, with fuel and oil for 4 1/2-hours; +thus loaded, they were required to fly for 3 hours, attaining an +altitude of 4,500 feet, maintaining a height of 1,500 feet for 1 hour, +and climbing 1,000 feet from the ground at a rate of 200 feet per +minute, 'although 300 feet per minute is desirable.' They had to attain +a speed of not less than 55 miles per hour in a calm, and be able to +plane down to the ground in a calm from not more than 1,000 feet with +engine stopped, traversing 6,000 feet horizontal distance. For those +days, the landing demands were rather exacting; the machine should be +able to rise without damage from long grass, clover, or harrowed land, +in 100 yards in a calm, and should be able to land without damage on any +cultivated ground, including rough ploughed land, and, when landing on +smooth turf in a calm, be able to pull up within 75 yards of the point +of first touching the ground. It was required that pilot and observer +should have as open a view as possible to front and flanks, and they +should be so shielded from the wind as to be able to communicate with +each other. These are the main provisions out of the set of conditions +laid down for competitors, but a considerable amount of leniency was +shown by the authorities in the competition, who obviously wished to try +out every machine entered and see what were its capabilities. + +The beginning of the competition consisted in assembling the machines +against time from road trim to flying trim. Cody's machine, which was +the only one to be delivered by air, took 1 hour and 35 minutes to +assemble; the best assembling time was that of the Avro, which was got +into flying trim in 14 minutes 30 seconds. This machine came to grief +with Lieut. Parke as pilot, on the 7th, through landing at very high +speed on very bad ground; a securing wire of the under-carriage broke in +the landing, throwing the machine forward on to its nose and then over +on its back. Parke was uninjured, fortunately; the damaged machine was +sent off to Manchester for repair and was back again on the 16th of +August. + +It is to be noted that by this time the Royal Aircraft Factory was +building aeroplanes of the B.E. and F.E. types, but at the same time it +is also to be noted that British military interest in engines was not +sufficient to bring them up to the high level attained by the planes, +and it is notorious that even the outbreak of war found England +incapable of providing a really satisfactory aero engine. In the 1912 +Trials, the only machines which actually completed all their tests were +the Cody biplane, the French Deperdussin, the Hanriot, two Bleriots and +a Maurice Farman. The first prize of L4,000, open to all the world, +went to F. S. Cody's British-built biplane, which complied with all +the conditions of the competition and well earned its official +acknowledgment of supremacy. The machine climbed at 280 feet per minute +and reached a height of 5,000 feet, while in the landing test, in spite +of its great weight and bulk, it pulled up on grass in 56 yards. The +total weight was 2,690 lbs. when fully loaded, and the total area of +supporting surface was 500 square feet; the motive power was supplied +by a six-cylinder 120 horsepower Austro-Daimler engine. The second prize +was taken by A. Deperdussin for the French-built Deperdussin monoplane. +Cody carried off the only prize awarded for a British-built plane, +this being the sum of L1,000, and consolation prizes of L500 each were +awarded to the British Deperdussin Company and The British and Colonial +Aeroplane Company, this latter soon to become famous as makers of the +Bristol aeroplane, of which the war honours are still fresh in men's +minds. + +While these trials were in progress Audemars accomplished the first +flight between Paris and Berlin, setting out from Issy early in the +morning of August 18th, landing at Rheims to refill his tanks within an +hour and a half, and then coming into bad weather which forced him +to land successively at Mezieres, Laroche, Bochum, and finally nearly +Gersenkirchen, where, owing to a leaky petrol tank, the attempt to win +the prize offered for the first flight between the two capitals had to +be abandoned after 300 miles had been covered, as the time limit was +definitely exceeded. Audemars determined to get through to Berlin, and +set off at 5 in the morning of the 19th, only to be brought down by fog; +starting off again at 9.15 he landed at Hanover, was off again at 1.35, +and reached the Johannisthal aerodrome in the suburbs of Berlin at 6.48 +that evening. + +As early as 1910 the British Government possessed some ten aeroplanes, +and in 1911 the force developed into the Army Air Battalion, with the +aeroplanes under the control of Major J. H. Fulton, R.F.A. Toward the +end of 1911 the Air Battalion was handed over to (then) Brig.-Gen. D. +Henderson, Director of Military Training. On June 6th, 1912, the Royal +Flying Corps was established with a military wing under Major F. H. +Sykes and a naval wing under Commander C. R. Samson. A joint Naval and +Military Flying School was established at Upavon with Captain Godfrey +M. Paine, R.N., as Commandant and Major Hugh Trenchard as Assistant +Commandant. The Royal Aircraft Factory brought out the B.E. and F.E. +types of biplane, admittedly superior to any other British design of the +period, and an Aircraft Inspection Department was formed under Major J. +H. Fulton. The military wing of the R.F.C. was equipped almost entirely +with machines of Royal Aircraft Factory design, but the Navy preferred +to develop British private enterprise by buying machines from private +firms. On July 1st, 1914 the establishment of the Royal Naval Air +Service marked the definite separation of the military and naval sides +of British aviation, but the Central Flying School at Upavon continued +to train pilots for both services. + +It is difficult at this length of time, so far as the military wing was +concerned, to do full justice to the spade work done by Major-General +Sir David Henderson in the early days. Just before war broke out, +British military air strength consisted officially of eight squadrons, +each of 12 machines and 13 in reserve, with the necessary complement of +road transport. As a matter of fact, there were three complete squadrons +and a part of a fourth which constituted the force sent to France at the +outbreak of war. The value of General Henderson's work lies in the fact +that, in spite of official stinginess and meagre supplies of every kind, +he built up a skeleton organisation so elastic and so well thought out +that it conformed to war requirements as well as even the German plans +fitted in with their aerial needs. On the 4th of August, 1914, the +nominal British air strength of the military wing was 179 machines. Of +these, 82 machines proceeded to France, landing at Amiens and flying +to Maubeuge to play their part in the great retreat with the British +Expeditionary Force, in which they suffered heavy casualties both in +personnel and machines. The history of their exploits, however, belongs +to the War period. + +The development of the aeroplane between 1912 and 1914 can be judged by +comparison of the requirements of the British War Office in 1912 with +those laid down in an official memorandum issued by the War Office +in February, 1914. This latter called for a light scout aeroplane, a +single-seater, with fuel capacity to admit of 300 miles range and a +speed range of from 50 to 85 miles per hour. It had to be able to climb +3,500 feet in five minutes, and the engine had to be so constructed that +the pilot could start it without assistance. At the same time, a heavier +type of machine for reconnaissance work was called for, carrying fuel +for a 200 mile flight with a speed range of between 35 and 60 miles per +hour, carrying both pilot and observer. It was to be equipped with +a wireless telegraphy set, and be capable of landing over a 30 foot +vertical obstacle and coming to rest within a hundred yards' distance +from the obstacle in a wind of not more than 15 miles per hour. A third +requirement was a heavy type of fighting aeroplane accommodating pilot +and gunner with machine gun and ammunition, having a speed range of +between 45 and 75 miles per hour and capable of climbing 3,500 feet in 8 +minutes. It was required to carry fuel for a 300 mile flight and to give +the gunner a clear field of fire in every direction up to 30 degrees on +each side of the line of flight. Comparison of these specifications with +those of the 1912 trials will show that although fighting, scouting, and +reconnaissance types had been defined, the development of performance +compared with the marvellous development of the earlier years of +achieved flight was small. + +Yet the records of those years show that here and there an outstanding +design was capable of great things. On the 9th September, 1912, +Vedrines, flying a Deperdussin monoplane at Chicago, attained a speed of +105 miles an hour. On August 12th, G. de Havilland took a passenger to a +height of 10,560 feet over Salisbury Plain, flying a B.E. biplane with +a 70 horse-power Renault engine. The work of de Havilland may be said to +have been the principal influence in British military aeroplane design, +and there is no doubt that his genius was in great measure responsible +for the excellence of the early B.E. and F.E. types. + +On the 31st May, 1913, H. G. Hawker, flying at Brooklands, reached +a height of 11,450 feet on a Sopwith biplane engined with an 80 +horse-power Gnome engine. On June 16th, with the same type of machine +and engine, he achieved 12,900 feet. On the 2nd October, in the same +year, a Grahame White biplane with 120 horse-power Austro-Daimler +engine, piloted by Louis Noel, made a flight of just under 20 minutes +carrying 9 passengers. In France a Nieuport monoplane piloted by G. +Legagneaux attained a height of 6,120 metres, or just over 20,070 feet, +this being the world's height record. It is worthy of note that of the +world's aviation records as passed by the International Aeronautical +Federation up to June 30th, 1914, only one, that of Noel, is credited to +Great Britain. + +Just as records were made abroad, with one exception, so were the +really efficient engines. In England there was the Green engine, but the +outbreak of war found the Royal Flying Corps with 80 horse-power Gnomes, +70 horse-power Renaults, and one or two Antoinette motors, but not one +British, while the Royal Naval Air Service had got 20 machines with +engines of similar origin, mainly land planes in which the wheeled +undercarriages had been replaced by floats. France led in development, +and there is no doubt that at the outbreak of war, the French military +aeroplane service was the best in the world. It was mainly composed of +Maurice Farman two-seater biplanes and Bleriot monoplanes--the latter +type banned for a period on account of a number of serious accidents +that took place in 1912. + +America had its Army Aviation School, and employed Burgess-Wright +and Curtiss machines for the most part. In the pre-war years, once +the Wright Brothers had accomplished their task, America's chief +accomplishment consisted in the development of the 'Flying Boat,' +alternatively named with characteristic American clumsiness, 'The +Hydro-Aeroplane.' In February of 1911, Glenn Curtiss attached a +float to a machine similar to that with which he won the first +Gordon-Bennett Air Contest and made his first flying boat +experiment. From this beginning he developed the boat form of body +which obviated the use and troubles of floats--his hydroplane became +its own float. + +Mainly owing to greater engine reliability the duration records steadily +increased. By September of 1912 Fourny, on a Maurice Farman biplane, was +able to accomplish a distance of 628 miles without a landing, remaining +in the air for 13 hours 17 minutes and just over 57 seconds. By 1914 +this was raised by the German aviator, Landemann, to 21 hours 48 3/4 +seconds. The nature of this last record shows that the factors in such a +record had become mere engine endurance, fuel capacity, and capacity +of the pilot to withstand air conditions for a prolonged period, rather +than any exceptional flying skill. + +Let these years be judged by the records they produced, and even then +they are rather dull. The glory of achievement such as characterised the +work of the Wright Brothers, of Bleriot, and of the giants of the early +days, had passed; the splendid courage, the patriotism and devotion +of the pilots of the War period had not yet come to being. There was +progress, past question, but it was mechanical, hardly ever inspired. +The study of climatic conditions was definitely begun and aeronautical +meteorology came to being, while another development already noted was +the fitting of wireless telegraphy to heavier-than-air machines, as +instanced in the British War office specification of February, 1914. +These, however, were inevitable; it remained for the War to force +development beyond the inevitable, producing in five years that which +under normal circumstances might easily have occupied fifty--the +aeroplane of to-day; for, as already remarked, there was a deadlock, +and any survey that may be made of the years 1912-1914, no matter how +superficial, must take it into account with a view to retaining correct +perspective in regard to the development of the aeroplane. + +There is one story of 1914 that must be included, however briefly, +in any record of aeronautical achievement, since it demonstrates past +question that to Professor Langley really belongs the honour of having +achieved a design which would ensure actual flight, although the series +of accidents which attended his experiments gave to the Wright Brothers +the honour of first leaving the earth and descending without accident in +a power-driven heavier-than-air machine. In March, 1914, Glenn Curtiss +was invited to send a flying boat to Washington for the celebration +of 'Langley Day,' when he remarked, 'I would like to put the Langley +aeroplane itself in the air.' In consequence of this remark, Secretary +Walcot of the Smithsonian Institution authorised Curtiss to re-canvas +the original Langley aeroplane and launch it either under its own power +or with a more recent engine and propeller. Curtiss completed this, and +had the machine ready on the shores of Lake Keuka, Hammondsport, N.Y., +by May. The main object of these renewed trials was to show whether the +original Langley machine was capable of sustained free flight with a +pilot, and a secondary object was to determine more fully the advantages +of the tandem monoplane type; thus the aeroplane was first flown +as nearly as possible in its original condition, and then with such +modifications as seemed desirable. The only difference made for the +first trials consisted in fitting floats with connecting trusses; +the steel main frame, wings, rudders, engine, and propellers were +substantially as they had been in 1903. The pilot had the same seat +under the main frame and the same general system of control. He could +raise or lower the craft by moving the rear rudder up and down; he could +steer right or left by moving the vertical rudder. He had no ailerons +nor wing-warping mechanism, but for lateral balance depended on the +dihedral angle of the wings and upon suitable movements of his weight or +of the vertical rudder. + +After the adjustments for actual flight had been made in the Curtiss +factory, according to the minute descriptions contained in the Langley +Memoir on Mechanical Flight, the aeroplane was taken to the shore of +Lake Keuka, beside the Curtiss hangars, and assembled for launching. On +a clear morning (May 28th) and in a mild breeze, the craft was lifted +on to the water by a dozen men and set going, with Mr Curtiss at the +steering wheel, esconced in the little boat-shaped car under the forward +part of the frame. The four-winged craft, pointed somewhat across the +wind, went skimming over the waveless, then automatically headed into +the wind, rose in level poise, soared gracefully for 150 feet, and +landed softly on the water near the shore. Mr Curtiss asserted that he +could have flown farther, but, being unused to the machine, imagined +that the left wings had more resistance than the right. The truth is +that the aeroplane was perfectly balanced in wing resistance, but turned +on the water like a weather vane, owing to the lateral pressure on +its big rear rudder. Hence in future experiments this rudder was made +turnable about a vertical axis, as well as about the horizontal axis +used by Langley. Henceforth the little vertical rudder under the frame +was kept fixed and inactive.[*] + +That the Langley aeroplane was subsequently fitted with an 80 +horse-power Curtiss engine and successfully flown is of little interest +in such a record as this, except for the fact that with the weight +nearly doubled by the new engine and accessories the machine flew +successfully, and demonstrated the perfection of Langley's design by +standing the strain. The point that is of most importance is that the +design itself proved a success and fully vindicated Langley's work. +At the same time, it would be unjust to pass by the fact of the flight +without according to Curtiss due recognition of the way in which he paid +tribute to the genius of the pioneer by these experiments. + +[*] Smithsonian Publications No. 2329. + + + + +XIX. THE WAR PERIOD--I + +Full record of aeronautical progress and of the accomplishments of +pilots in the years of the War would demand not merely a volume, but a +complete library, and even then it would be barely possible to pay full +tribute to the heroism of pilots of the war period. There are names +connected with that period of which the glory will not fade, names such +as Bishop, Guynemer, Boelcke, Ball, Fonck, Immelmann, and many others +that spring to mind as one recalls the 'Aces' of the period. In +addition to the pilots, there is the stupendous development of the +machines--stupendous when the length of the period in which it was +achieved is considered. + +The fact that Germany was best prepared in the matter of +heavier-than-air service machines in spite of the German faith in the +dirigible is one more item of evidence as to who forced hostilities. +The Germans came into the field with well over 600 aeroplanes, mainly +two-seaters of standardised design, and with factories back in the +Fatherland turning out sufficient new machines to make good the +losses. There were a few single-seater scouts built for speed, and the +two-seater machines were all fitted with cameras and bomb-dropping gear. +Manoeuvres had determined in the German mind what should be the uses of +the air fleet; there was photography of fortifications and field works; +signalling by Very lights; spotting for the guns, and scouting for news +of enemy movements. The methodical German mind had arranged all this +beforehand, but had not allowed for the fact that opponents might take +counter-measures which would upset the over-perfect mechanism of the air +service just as effectually as the great march on Paris was countered by +the genius of Joffre. + +The French Air Force at the beginning of the War consisted of upwards of +600 machines. These, unlike the Germans, were not standardised, but were +of many and diverse types. In order to get replacements quickly enough, +the factories had to work on the designs they had, and thus for a +long time after the outbreak of hostilities standardisation was an +impossibility. The versatility of a Latin race in a measure compensated +for this; from the outset, the Germans tried to overwhelm the French +Air Force, but failed, since they had not the numerical superiority, +nor--this equally a determining factor--the versatility and resource +of the French pilots. They calculated on a 50 per cent superiority to +ensure success; they needed more nearly 400 per cent, for the German +fought to rule, avoiding risks whenever possible, and definitely +instructed to save both machines and pilots wherever possible. French +pilots, on the other hand, ran all the risks there were, got news +of German movements, bombed the enemy, and rapidly worked up a very +respectable antiaircraft force which, whatever it may have accomplished +in the way of hitting German planes, got on the German pilots' nerves. + +It has already been detailed how Britain sent over 82 planes as its +contribution to the military aerial force of 1914. These consisted of +Farman, Caudron, and Short biplanes, together with Bleriot, Deperdussin +and Nieuport monoplanes, certain R.A.F. types, and other machines of +which even the name barely survives--the resourceful Yankee entitles +them 'orphans.' It is on record that the work of providing spares might +have been rather complicated but for the fact that there were none. + +There is no doubt that the Germans had made study of aerial +military needs just as thoroughly as they had perfected their ground +organisation. Thus there were 21 illuminated aircraft stations in +Germany before the War, the most powerful being at Weimar, where a +revolving electric flash of over 27 million candle-power was located. +Practically all German aeroplane tests in the period immediately +preceding the War were of a military nature, and quite a number of +reliability tests were carried out just on the other side of the French +frontier. Night flying and landing were standardised items in the German +pilot's course of instruction while they were still experimental in +other countries, and a system of signals was arranged which rendered the +instructional course as perfect as might be. + +The Belgian contribution consisted of about twenty machines fit for +active service and another twenty which were more or less useful as +training machines. The material was mainly French, and the Belgian +pilots used it to good account until German numbers swamped them. +France, and to a small extent England, kept Belgian aviators supplied +with machines throughout the War. + +The Italian Air Fleet was small, and consisted of French machines +together with a percentage of planes of Italian origin, of which the +design was very much a copy of French types. It was not until the War +was nearing its end that the military and naval services relied more +on the home product than on imports. This does not apply to engines, +however, for the F.I.A.T. and S.C.A.T. were equal to practically any +engine of Allied make, both in design and construction. + +Russia spent vast sums in the provision of machines: the giant Sikorsky +biplane, carrying four 100 horsepower Argus motors, was designed by +a young Russian engineer in the latter part of 1913, and in its early +trials it created a world's record by carrying seven passengers for +1 hour 54 minutes. Sikorsky also designed several smaller machines, +tractor biplanes on the lines of the British B.E. type, which were +very successful. These were the only home productions, and the imports +consisted mainly of French aeroplanes by the hundred, which got as +far as the docks and railway sidings and stayed there, while German +influence and the corruption that ruined the Russian Army helped to lose +the War. A few Russian aircraft factories were got into operation as +hostilities proceeded, but their products were negligible, and it is not +on record that Russia ever learned to manufacture a magneto. + +The United States paid tribute to British efficiency by adopting the +British system of training for its pilots; 500 American cadets were +trained at the School of Military Aeronautics at oxford, in order to +form a nucleus for the American aviation schools which were subsequently +set up in the United States and in France. As regards production of +craft, the designing of the Liberty engine and building of over 20,000 +aeroplanes within a year proves that America is a manufacturing country, +even under the strain of war. + +There were three years of struggle for aerial supremacy, the combatants +being England and France against Germany, and the contest was neck +and neck all the way. Germany led at the outset with the standardised +two-seater biplanes manned by pilots and observers, whose training +was superior to that afforded by any other nation, while the machines +themselves were better equipped and fitted with accessories. All the +early German aeroplanes were designated Taube by the uninitiated, and +were formed with swept-back, curved wings very much resembling the wings +of a bird. These had obvious disadvantages, but the standardisation +of design and mass production of the German factories kept them in the +field for a considerable period, and they flew side by side with tractor +biplanes of improved design. For a little time, the Fokker monoplane +became a definite threat both to French and British machines. It was +an improvement on the Morane French monoplane, and with a high-powered +engine it climbed quickly and flew fast, doing a good deal of damage for +a brief period of 1915. Allied design got ahead of it and finally drove +it out of the air. + +German equipment at the outset, which put the Allies at a disadvantage, +included a hand-operated magneto engine-starter and a small independent +screw which, mounted on one of the main planes, drove the dynamo used +for the wireless set. Cameras were fitted on practically every machine; +equipment included accurate compasses and pressure petrol gauges, speed +and height recording instruments, bomb-dropping fittings and sectional +radiators which facilitated repairs and gave maximum engine efficiency +in spite of variations of temperature. As counter to these, the Allied +pilots had resource amounting to impudence. In the early days they +carried rifles and hand grenades and automatic pistols. They loaded +their machines down, often at their own expense, with accessories and +fittings until their aeroplanes earned their title of Christmas trees. +They played with death in a way that shocked the average German pilot +of the War's early stages, declining to fight according to rule and +indulging in the individual duels of the air which the German hated. +As Sir John French put it in one of his reports, they established a +personal ascendancy over the enemy, and in this way compensated for +their inferior material. + +French diversity of design fitted in well with the initiative and +resource displayed by the French pilots. The big Caudron type was the +ideal bomber of the early days; Farman machines were excellent for +reconnaissance and artillery spotting; the Bleriots proved excellent +as fighting scouts and for aerial photography; the Nieuports made good +fighters, as did the Spads, both being very fast craft, as were the +Morane-Saulnier monoplanes, while the big Voisin biplanes rivalled the +Caudron machines as bombers. + +The day of the Fokker ended when the British B.E.2.C. aeroplane came +to France in good quantities, and the F.E. type, together with the De +Havilland machines, rendered British aerial superiority a certainty. +Germany's best reply--this was about 1916--was the Albatross biplane, +which was used by Captain Baron von Richthofen for his famous travelling +circus, manned by German star pilots and sent to various parts of the +line to hearten up German troops and aviators after any specially bad +strafe. Then there were the Aviatik biplane and the Halberstadt fighting +scout, a cleanly built and very fast machine with a powerful engine with +which Germany tried to win back superiority in the third year of the +War, but Allied design kept about three months ahead of that of the +enemy, once the Fokker had been mastered, and the race went on. Spads +and Bristol fighters, Sopwith scouts and F.E.'s played their part in the +race, and design was still advancing when peace came. + +The giant twin-engined Handley-Page bomber was tried out, proved +efficient, and justly considered better than anything of its kind that +had previously taken the field. Immediately after the conclusion of its +trials, a specimen of the type was delivered intact at Lille for the +Germans to copy, the innocent pilot responsible for the delivery doing +some great disservice to his own cause. The Gotha Wagon-Fabrik Firm +immediately set to work and copied the Handley-Page design, producing +the great Gotha bombing machine which was used in all the later raids on +England as well as for night work over the Allied lines. + +How the War advanced design may be judged by comparison of the military +requirements given for the British Military Trials of 1912, with +performances of 1916 and 1917, when the speed of the faster machines had +increased to over 150 miles an hour and Allied machines engaged enemy +aircraft at heights ranging up to 22,000 feet. All pre-war records of +endurance, speed, and climb went by the board, as the race for aerial +superiority went on. + +Bombing brought to being a number of crude devices in the first year of +the War. Allied pilots of the very early days carried up bombs packed +in a small box and threw them over by hand, while, a little later, the +bombs were strung like apples on wings and undercarriage, so that +the pilot who did not get rid of his load before landing risked an +explosion. Then came a properly designed carrying apparatus, crude but +fairly efficient, and with 1916 development had proceeded as far as the +proper bomb-racks with releasing gear. + +Reconnaissance work developed, so that fighting machines went as escort +to observing squadrons and scouting operations were undertaken up to 100 +miles behind the enemy lines; out of this grew the art of camouflage, +when ammunition dumps were painted to resemble herds of cows, guns were +screened by foliage or painted to merge into a ground scheme, and many +other schemes were devised to prevent aerial observation. Troops were +moved by night for the most part, owing to the keen eyes of the air +pilots and the danger of bombs, though occasionally the aviator had his +chance. There is one story concerning a British pilot who, on returning +from a reconnaissance flight, observed a German Staff car on the road +under him; he descended and bombed and machine--gunned the car until the +German General and his chauffeur abandoned it, took to their heels, and +ran like rabbits. Later still, when Allied air superiority was assured, +there came the phase of machine-gunning bodies of enemy troops from the +air. Disregarding all antiaircraft measures, machines would sweep down +and throw battalions into panic or upset the military traffic along a +road, demoralising a battery or a transport train and causing as much +damage through congestion of traffic as with their actual machine-gun +fire. Aerial photography, too, became a fine art; the ordinary long +focus cameras were used at the outset with automatic plate changers, but +later on photographing aeroplanes had cameras of wide angle lens type +built into the fuselage. These were very simply operated, one lever +registering the exposure and changing the plate. In many cases, aerial +photographs gave information which the human eye had missed, and it is +noteworthy that photographs of ground showed when troops had marched +over it, while the aerial observer was quite unable to detect the marks +left by their passing. + +Some small mention must be made of seaplane activities, which, round +the European coasts involved in the War, never ceased. The submarine +campaign found in the spotting seaplane its greatest deterrent, and it +is old news now how even the deeply submerged submarines were easily +picked out for destruction from a height and the news wirelessed from +seaplane to destroyer, while in more than one place the seaplane itself +finished the task by bomb dropping. It was a seaplane that gave Admiral +Beatty the news that the whole German Fleet was out before the Jutland +Battle, news which led to a change of plans that very nearly brought +about the destruction of Germany's naval power. For the most part, the +seaplanes of the War period were heavier than the land machines and, in +the opinion of the land pilots, were slow and clumsy things to fly. This +was inevitable, for their work demanded more solid building and greater +reliability. To put the matter into Hibernian phrase, a forced landing +at sea is a much more serious matter than on the ground. Thus there was +need for greater engine power, bigger wingspread to support the floats, +and fuel tanks of greater capacity. The flying boats of the later +War period carried considerable crews, were heavily armed, capable of +withstanding very heavy weather, and carried good loads of bombs on +long cruises. Their work was not all essentially seaplane work, for the +R.N.A.S. was as well known as hated over the German airship sheds in +Belgium and along the Flanders coast. As regards other theatres of War, +they rendered valuable service from the Dardanelles to the Rufiji River, +at this latter place forming a principal factor in the destruction of +the cruiser Konigsberg. Their spotting work at the Dardanelles for +the battleships was responsible for direct hits from 15 in. guns on +invisible targets at ranges of over 12,000 yards. Seaplane pilots were +bombing specialists, including among their targets army headquarters, +ammunition dumps, railway stations, submarines and their bases, docks, +shipping in German harbours, and the German Fleet at Wilhelmshaven. +Dunkirk, a British seaplane base, was a sharp thorn in the German side. + +Turning from consideration of the various services to the exploits of +the men composing them, it is difficult to particularise. A certain +inevitable prejudice even at this length of time leads one to discount +the valour of pilots in the German Air Service, but the names of +Boelcke, von Richthofen, and Immelmann recur as proof of the courage +that was not wanting in the enemy ranks, while, however much we may +decry the Gotha raids over the English coast and on London, there is no +doubt that the men who undertook these raids were not deficient in the +form of bravery that is of more value than the unthinking valour of +a minute which, observed from the right quarter, wins a military +decoration. + +Yet the fact that the Allied airmen kept the air at all in the early +days proved on which side personal superiority lay, for they were +outnumbered, out-manoeuvred, and faced by better material than any +that they themselves possessed; yet they won their fights or died. The +stories of their deeds are endless; Bishop, flying alone and meeting +seven German machines and crashing four; the battle of May 5th, 1915, +when five heroes fought and conquered twenty-seven German machines, +ranging in altitude between 12,000 and 3,000 feet, and continuing the +extraordinary struggle from five until six in the evening. Captain +Aizlewood, attacking five enemy machines with such reckless speed that +he rammed one and still reached his aerodrome safely--these are items in +a long list of feats of which the character can only be realised when +it is fully comprehended that the British Air Service accounted for some +8,000 enemy machines in the course of the War. Among the French there +was Captain Guynemer, who at the time of his death had brought down +fifty-four enemy machines, in addition to many others of which the +destruction could not be officially confirmed. There was Fonck, who +brought down six machines in one day, four of them within two minutes. + +There are incredible stories, true as incredible, of shattered men +carrying on with their work in absolute disregard of physical injury. +Major Brabazon Rees, V.C., engaged a big German battle-plane in +September of 1915 and, single-handed, forced his enemy out of action. +Later in his career, with a serious wound in the thigh from which blood +was pouring, he kept up a fight with an enemy formation until he had not +a round of ammunition left, and then returned to his aerodrome to get +his wound dressed. Lieutenants Otley and Dunning, flying in the Balkans, +engaged a couple of enemy machines and drove them off, but not until +their petrol tank had got a hole in it and Dunning was dangerously +wounded in the leg. Otley improvised a tourniquet, passed it to Dunning, +and, when the latter had bandaged himself, changed from the observer's +to the pilot's seat, plugged the bullet hole in the tank with his thumb +and steered the machine home. + +These are incidents; the full list has not been, and can never be +recorded, but it goes to show that in the pilot of the War period there +came to being a new type of humanity, a product of evolution which +fitted a certain need. Of such was Captain West, who, engaging hostile +troops, was attacked by seven machines. Early in the engagement, one of +his legs was partially severed by an explosive bullet and fell powerless +into the controls, rendering the machine for the time unmanageable. +Lifting his disabled leg, he regained control of the machine, and +although wounded in the other leg, he manoeuvred his machine so +skilfully that his observer was able to get several good bursts into the +enemy machines, driving them away. Then, desperately wounded as he +was, Captain West brought the machine over to his own lines and landed +safely. He fainted from loss of blood and exhaustion, but on regaining +consciousness, insisted on writing his report. Equal to this was the +exploit of Captain Barker, who, in aerial combat, was wounded in the +right and left thigh and had his left arm shattered, subsequently +bringing down an enemy machine in flames, and then breaking through +another hostile formation and reaching the British lines. + +In recalling such exploits as these, one is tempted on and on, for it +seems that the pilots rivalled each other in their devotion to duty, +this not confined to British aviators, but common practically to all +services. Sufficient instances have been given to show the nature of the +work and the character of the men who did it. + +The rapid growth of aerial effort rendered it necessary in January of +1915 to organise the Royal Flying Corps into separate wings, and in +October of the same year it was constituted in Brigades. In 1916 the +Air Board was formed, mainly with the object of co-ordinating effort +and ensuring both to the R.N.A.S. and to the R.F.C. adequate supplies of +material as far as construction admitted. Under the presidency of Lord +Cowdray, the Air Board brought about certain reforms early in 1917, +and in November of that year a separate Air Ministry was constituted, +separating the Air Force from both Navy and Army, and rendering it an +independent force. On April 1st, 1918, the Royal Air Force came into +existence, and unkind critics in the Royal Flying Corps remarked on the +appropriateness of the date. At the end of the War, the personnel of the +Royal Air Force amounted to 27,906 officers, and 263,842 other ranks. +Contrast of these figures with the number of officers and men who took +the field in 1914 is indicative of the magnitude of British aerial +effort in the War period. + + + + +XX. THE WAR PERIOD--II + +There was when War broke out no realisation on the part of the British +Government of the need for encouraging the enterprise of private +builders, who carried out their work entirely at their-own cost. The +importance of a supply of British-built engines was realised before the +War, it is true, and a competition was held in which a prize of L5,000 +was offered for the best British engine, but this awakening was so late +that the R.F.C. took the field without a single British power plant. +Although Germany woke up equally late to the need for home produced +aeroplane engines, the experience gained in building engines for +dirigibles sufficed for the production of aeroplane power plants. The +Mercedes filled all requirements together with the Benz and the Maybach. +There was a 225 horsepower Benz which was very popular, as were the 100 +horse-power and 170 horse-power Mercedes, the last mentioned fitted to +the Aviatik biplane of 1917. The Uberursel was a copy of the Gnome and +supplied the need for rotary engines. + +In Great Britain there were a number of aeroplane constructing firms +that had managed to emerge from the lean years 1912-1913 with +sufficient manufacturing plant to give a hand in making up the leeway of +construction when War broke out. Gradually the motor-car firms came +in, turning their body-building departments to plane and fuselage +construction, which enabled them to turn out the complete planes engined +and ready for the field. The coach-building trade soon joined in and +came in handy as propeller makers; big upholstering and furniture firms +and scores of concerns that had never dreamed of engaging in aeroplane +construction were busy on supplying the R.F.C. By 1915 hundreds of +different firms were building aeroplanes and parts; by 1917 the number +had increased to over 1,000, and a capital of over a million pounds for +a firm that at the outbreak of War had employed a score or so of hands +was by no means uncommon. Women and girls came into the work, more +especially in plane construction and covering and doping, though they +took their place in the engine shops and proved successful at acetylene +welding and work at the lathes. It was some time before Britain was able +to provide its own magnetos, for this key industry had been left in +the hands of the Germans up to the outbreak of War, and the 'Bosch' was +admittedly supreme--even now it has never been beaten, and can only be +equalled, being as near perfection as is possible for a magneto. + +One of the great inventions of the War was the synchronisation of +engine-timing and machine gun, which rendered it possible to fire +through the blades of a propeller without damaging them, though the +growing efficiency of the aeroplane as a whole and of its armament is +a thing to marvel at on looking back and considering what was actually +accomplished. As the efficiency of the aeroplane increased, so +anti-aircraft guns and range-finding were improved. Before the War an +aeroplane travelling at full speed was reckoned perfectly safe at 4,000 +feet, but, by the first month of 1915, the safe height had gone up to +9,000 feet, 7,000 feet being the limit of rifle and machine gun bullet +trajectory; the heavier guns were not sufficiently mobile to tackle +aircraft. At that time, it was reckoned that effective aerial +photography ceased at 6,000 feet, while bomb-dropping from 7,000-8,000 +feet was reckoned uncertain except in the case of a very large target. +The improvement in anti-aircraft devices went on, and by May of 1916, an +aeroplane was not safe under 15,000 feet, while anti-aircraft shells had +fuses capable of being set to over 20,000 feet, and bombing from 15,000 +and 16,000 feet was common. It was not till later that Allied pilots +demonstrated the safety that lies in flying very near the ground, this +owing to the fact that, when flying swiftly at a very low altitude, the +machine is out of sight almost before it can be aimed at. + +The Battle of the Somme and the clearing of the air preliminary to that +operation brought the fighting aeroplane pure and simple with them. +Formations of fighting planes preceded reconnaissance craft in order +to clear German machines and observation balloons out of the sky and to +watch and keep down any further enemy formations that might attempt +to interfere with Allied observation work. The German reply to this +consisted in the formation of the Flying Circus, of which Captain Baron +von Richthofen's was a good example. Each circus consisted of a large +formation of speedy machines, built specially for fighting and manned +by the best of the German pilots. These were sent to attack at any point +along the line where the Allies had got a decided superiority. + +The trick flying of pre-war days soon became an everyday matter; Pegoud +astonished the aviation world before the War by first looping the loop, +but, before three years of hostilities had elapsed, looping was part of +the training of practically every pilot, while the spinning nose dive, +originally considered fatal, was mastered, and the tail slide, which +consisted of a machine rising nose upward in the air and falling back on +its tail, became one of the easiest 'stunts' in the pilot's repertoire. +Inherent stability was gradually improved, and, from 1916 onward, +practically every pilot could carry on with his machine-gun or camera +and trust to his machine to fly itself until he was free to attend to +it. There was more than one story of a machine coming safely to earth +and making good landing on its own account with the pilot dead in his +cock-pit. + +Toward the end of the War, the Independent Air Force was formed as a +branch of the R.A.F. with a view to bombing German bases and devoting +its attention exclusively to work behind the enemy lines. Bombing +operations were undertaken by the R.N.A.S. as early as 1914-1915 against +Cuxhaven, Dusseldorf, and Friedrichshavn, but the supply of material was +not sufficient to render these raids continuous. A separate Brigade, +the 8th, was formed in 1917 to harass the German chemical and iron +industries, the base being in the Nancy area, and this policy was found +so fruitful that the Independent Force was constituted on the 8th June, +1918. The value of the work accomplished by this force is demonstrated +by the fact that the German High Command recalled twenty fighting +squadrons from the Western front to counter its activities, and, in +addition, took troops away from the fighting line in large numbers for +manning anti-aircraft batteries and searchlights. The German press of +the last year of the War is eloquent of the damage done in manufacturing +areas by the Independent Force, which, had hostilities continued a +little longer, would have included Berlin in its activities. + +Formation flying was first developed by the Germans, who made use of it +in the daylight raids against England in 1917. Its value was very soon +realised, and the V formation of wild geese was adopted, the leader +taking the point of the V and his squadron following on either side at +different heights. The air currents set up by the leading machines were +thus avoided by those in the rear, while each pilot had a good view +of the leader's bombs, and were able to correct their own aim by +the bursts, while the different heights at which they flew rendered +anti-aircraft gun practice less effective. Further, machines were able +to afford mutual protection to each other and any attacker would be +met by machine-gun fire from three or four machines firing on him from +different angles and heights. In the later formations single-seater +fighters flew above the bombers for the purpose of driving off hostile +craft. Formation flying was not fully developed when the end of the War +brought stagnation in place of the rapid advance in the strategy and +tactics of military air work. + + + + +XXI. RECONSTRUCTION + +The end of the War brought a pause in which the multitude of aircraft +constructors found themselves faced with the possible complete +stagnation of the industry, since military activities no longer demanded +their services and the prospects of commercial flying were virtually +nil. That great factor in commercial success, cost of plant and upkeep, +had received no consideration whatever in the War period, for armies do +not count cost. The types of machines that had evolved from the War +were very fast, very efficient, and very expensive, although the bombers +showed promise of adaptation to commercial needs, and, so far as other +machines were concerned, America had already proved the possibilities of +mail-carrying by maintaining a mail service even during the War period. + +A civil aviation department of the Air Ministry was formed in February +of 1919 with a Controller General of Civil Aviation at the head. This +was organised into four branches, one dealing with the survey and +preparation of air routes for the British Empire, one organising +meteorological and wireless telegraphy services, one dealing with the +licensing of aerodromes, machines for passenger or goods carrying and +civilian pilots, and one dealing with publicity and transmission of +information generally. A special Act of Parliament 264 entitled 'The Air +Navigation Acts, 1911-1919,' was passed on February 27th, and commercial +flying was officially permitted from May 1st, 1919. + +Meanwhile the great event of 1919, the crossing of the Atlantic by air, +was gradually ripening to performance. In addition to the rigid airship, +R.34, eight machines entered for this flight, these being a Short +seaplane, Handley-Page, Martinsyde, Vickers-Vimy, and Sopwith +aeroplanes, and three American flying boats, N.C.1, N.C.3, and N.C.4. +The Short seaplane was the only one of the eight which proposed to make +the journey westward; in flying from England to Ireland, before starting +on the long trip to Newfoundland, it fell into the sea off the coast of +Anglesey, and so far as it was concerned the attempt was abandoned. + +The first machines to start from the Western end were the three American +seaplanes, which on the morning of May 6th left Trepassy, Newfoundland, +on the 1,380 mile stage to Horta in the Azores. N.C.1 and N.C.3 gave +up the attempt very early, but N.C.4, piloted by Lieut.-Commander Read, +U.S.N., made Horta on May 17th and made a three days' halt. On the 20th +the second stage of the journey to Ponta Delgada, a further 190 miles, +was completed and a second halt of a week was made. On the 27th, the +machine left for Lisbon, 900 miles distant, and completed the journey in +a day. On the 30th a further stage of 340 miles took N.C.4 on to +Ferrol, and the next day the last stage of 420 miles to Plymouth was +accomplished. + +Meanwhile, H. G. Hawker, pilot of the Sopwith biplane, together with +Commander Mackenzie Grieve, R.N., his navigator, found the weather +sufficiently auspicious to set out at 6.48 p.m. On Sunday, May 18th, in +the hope of completing the trip by the direct route before N.C.4 could +reach Plymouth. They set out from Mount Pearl aerodrome, St John's, +Newfoundland, and vanished into space, being given up as lost, as Hamel +was lost immediately before the War in attempting to fly the North +Sea. There was a week of dead silence regarding their fate, but on the +following Sunday morning there was world-wide relief at the news that +the plucky attempt had not ended in disaster, but both aviators had been +picked up by the steamer Mary at 9.30 a.m. on the morning of the 19th, +while still about 750 miles short of the conclusion of their journey. +Engine failure brought them down, and they planed down to the sea close +to the Mary to be picked up; as the vessel was not fitted with wireless, +the news of their rescue could not be communicated until land was +reached. An equivalent of half the L10,000 prize offered by the Daily +Mail for the non-stop flight was presented by the paper in recognition +of the very gallant attempt, and the King conferred the Air Force Cross +on both pilot and navigator. + +Raynham, pilot of the Martinsyde competing machine, had the bad luck to +crash his craft twice in attempting to start before he got outside the +boundary of the aerodrome. The Handley-Page machine was withdrawn from +the competition, and, attempting to fly to America, was crashed on the +way. + +The first non-stop crossing was made on June 14th-15th in 16 hours 27 +minutes, the speed being just over 117 miles per hour. The machine was a +Vickers-Vimy bomber, engined with two Rolls-Royce Eagle VIII's, piloted +by Captain John Alcock, D.S.C., with Lieut. Arthur Whitten-Brown as +navigator. The journey was reported to be very rough, so much so at +times that Captain Alcock stated that they were flying upside down, and +for the greater part of the time they were out of sight of the sea. Both +pilot and navigator had the honour of knighthood conferred on them at +the conclusion of the journey. + +Meanwhile, commercial flying opened on May 8th (the official date +was May 1st) with a joy-ride service from Hounslow of Avro training +machines. The enterprise caught on remarkably, and the company extended +their activities to coastal resorts for the holiday season--at Blackpool +alone they took up 10,000 passengers before the service was two months +old. Hendon, beginning passenger flights on the same date, went in for +exhibition and passenger flying, and on June 21st the aerial Derby +was won by Captain Gathergood on an Airco 4R machine with a Napier 450 +horse-power 'Lion' engine; incidentally the speed of 129.3 miles per +hour was officially recognised as constituting the world's record for +speed within a closed circuit. On July 17th a Fiat B.R. biplane with a +700 horse-power engine landed at Kenley aerodrome after having made a +non-stop flight of 1,100 miles. The maximum speed of this machine was +160 miles per hour, and it was claimed to be the fastest machine in +existence. On August 25th a daily service between London and Paris was +inaugurated by the Aircraft Manufacturing Company, Limited, who ran a +machine each way each day, starting at 12.30 and due to arrive at 2.45 +p.m. The Handley-Page Company began a similar service in September +of 1919, but ran it on alternate days with machines capable of +accommodating ten passengers. The single fare in each case was fixed at +15 guineas and the parcel rate at 7s. 6d. per pound. + +Meanwhile, in Germany, a number of passenger services had been in +operation from the early part of the year; the Berlin-Weimar service was +established on February 5th and Berlin-Hamburg on March 1st, both for +mail and passenger carrying. Berlin-Breslau was soon added, but the +first route opened remained most popular, 538 flights being made between +its opening and the end of April, while for March and April combined, +the Hamburg-Berlin route recorded only 262 flights. All three routes +were operated by a combine of German aeronautical firms entitled the +Deutsch Luft Rederie. The single fare between Hamburg and Berlin was +450 marks, between Berlin and Breslau 500 marks, and between Berlin +and Weimar 450 marks. Luggage was carried free of charge, but varied +according to the weight of the passenger, since the combined weight of +both passenger and luggage was not allowed to exceed a certain limit. + +In America commercial flying had begun in May of 1918 with the mail +service between Washington, Philadelphia, and New York, which proved +that mail carrying is a commercial possibility, and also demonstrated +the remarkable reliability of the modern aeroplane by making 102 +complete flights out of a possible total of 104 in November, 1918, at a +cost of 0.777 of a dollar per mile. By March of 1919 the cost per mile +had gone up to 1.28 dollars; the first annual report issued at the +end of May showed an efficiency of 95.6 per cent and the original +six aeroplanes and engines with which the service began were still in +regular use. + +In June of 1919 an American commercial firm chartered an aeroplane for +emergency service owing to a New York harbour strike and found it so +useful that they made it a regular service. The Travellers Company +inaugurated a passenger flying boat service between New York and +Atlantic City on July 25th, the fare, inclusive of 35 lbs. of luggage, +being fixed at L25 each way. + +Five flights on the American continent up to the end of 1919 are worthy +of note. On December 13th, 1918, Lieut. D. Godoy of the Chilian army +left Santiago, Chili, crossed the Andes at a height of 19,700 feet +and landed at Mendoza, the capital of the wine-growing province of +Argentina. On April 19th, 1919, Captain E. F. White made the first +non-stop flight between New York and Chicago in 6 hours 50 minutes on +a D.H.4 machine driven by a twelve-cylinder Liberty engine. Early in +August Major Schroeder, piloting a French Lepere machine flying at a +height of 18,400 feet, reached a speed of 137 miles per hour with a +Liberty motor fitted with a super-charger. Toward the end of August, Rex +Marshall, on a Thomas-Morse biplane, starting from a height of 17,000 +feet, made a glide of 35 miles with his engine cut off, restarting it +when at a height of 600 feet above the ground. About a month later R. +Rohlfe, piloting a Curtiss triplane, broke the height record by reaching +34,610 feet. + + + + +XXII. 1919-20 + +Into the later months of 1919 comes the flight by Captain Ross-Smith +from England to Australia and the attempt to make the Cape to Cairo +voyage by air. The Australian Government had offered a prize of L10,000 +for the first flight from England to Australia in a British machine, the +flight to be accomplished in 720 consecutive hours. Ross-Smith, with his +brother, Lieut. Keith Macpherson Smith, and two mechanics, left Hounslow +in a Vickers-Vimy bomber with Rolls-Royce engine on November 12th and +arrived at Port Darwin, North Australia, on the 10th December, having +completed the flight in 27 days 20 hours 20 minutes, thus having 51 +hours 40 minutes to spare out of the 720 allotted hours. + +Early in 1920 came a series of attempts at completing the journey by air +between Cairo and the Cape. Out of four competitors Colonel Van Ryneveld +came nearest to making the journey successfully, leaving England on +a standard Vickers-Vimy bomber with Rolls-Royce engines, identical in +design with the machine used by Captain Ross-Smith on the England +to Australia flight. A second Vickers-Vimy was financed by the Times +newspaper and a third flight was undertaken with a Handley-Page machine +under the auspices of the Daily Telegraph. The Air Ministry had already +prepared the route by means of three survey parties which cleared the +aerodromes and landing grounds, dividing their journey into stages of +200 miles or less. Not one of the competitors completed the course, but +in both this and Ross-Smith's flight valuable data was gained in +respect of reliability of machines and engines, together with a mass of +meteorological information. + +The Handley-Page Company announced in the early months of 1920 that they +had perfected a new design of wing which brought about a twenty to forty +per cent improvement in lift rate in the year. When the nature of the +design was made public, it was seen to consist of a division of the +wing into small sections, each with its separate lift. A few days later, +Fokker, the Dutch inventor, announced the construction of a machine in +which all external bracing wires are obviated, the wings being of a +very deep section and self-supporting. The value of these two inventions +remains to be seen so far as commercial flying is concerned. + +The value of air work in war, especially so far as the Colonial +campaigns in which British troops are constantly being engaged is in +question, was very thoroughly demonstrated in a report issued early +in 1920 with reference to the successful termination of the Somaliland +campaign through the intervention of the Royal Air Force, which between +January 21st and the 31st practically destroyed the Dervish force under +the Mullah, which had been a thorn in the side of Britain since 1907. +Bombs and machine-guns did the work, destroying fortifications and +bringing about the surrender of all the Mullah's following, with the +exception of about seventy who made their escape. + +Certain records both in construction and performance had characterised +the post-war years, though as design advances and comes nearer to +perfection, it is obvious that records must get fewer and farther +between. The record aeroplane as regards size at the time of its +construction was the Tarrant triplane, which made its first--and +last--flight on May 28th, 1919. The total loaded weight was 30 tons, +and the machine was fitted with six 400 horse-power engines; almost +immediately after the trial flight began, the machine pitched forward +on its nose and was wrecked, causing fatal injuries to Captains Dunn +and Rawlings, who were aboard the machine. A second accident of +similar character was that which befell the giant seaplane known as the +Felixstowe Fury, in a trial flight. This latter machine was intended to +be flown to Australia, but was crashed over the water. + +On May 4th, 1920, a British record for flight duration and useful +load was established by a commercial type Handley-Page biplane, which, +carrying a load of 3,690 lbs., rose to a height of 13,999 feet and +remained in the air for 1 hour 20 minutes. On May 27th the French pilot, +Fronval, flying at Villacoublay in a Morane-Saulnier type of biplane +with Le Rhone motor, put up an extraordinary type of record by looping +the loop 962 times in 3 hours 52 minutes 10 seconds. Another record of +the year of similar nature was that of two French fliers, Boussotrot +and Bernard, who achieved a continuous flight of 24 hours 19 minutes 7 +seconds, beating the pre-war record of 21 hours 48 3/4 seconds set up +by the German pilot, Landemann. Both these records are likely to stand, +being in the nature of freaks, which demonstrate little beyond the +reliability of the machine and the capacity for endurance on the part of +its pilots. + +Meanwhile, on February 14th, Lieuts. Masiero and Ferrarin left Rome on +S.V.A. Ansaldo V. machines fitted with 220 horse-power S.V.A. motors. On +May 30th they arrived at Tokio, having flown by way of Bagdad, Karachi, +Canton, Pekin, and Osaka. Several other competitors started, two of whom +were shot down by Arabs in Mesopotamia. + +Considered in a general way, the first two years after the termination +of the Great European War form a period of transition in which the +commercial type of aeroplane was gradually evolved from the fighting +machine which was perfected in the four preceding years. There was about +this period no sense of finality, but it was as experimental, in its +own way, as were the years of progressing design which preceded the war +period. Such commercial schemes as were inaugurated call for no more +note than has been given here; they have been experimental, and, with +the possible exception of the United States Government mail service, +have not been planned and executed on a sufficiently large scale to +furnish reliable data on which to forecast the prospects of commercial +aviation. And there is a school rapidly growing up which asserts that +the day of aeroplanes is nearly over. The construction of the giant +airships of to-day and the successful return flight of R34 across +the Atlantic seem to point to the eventual triumph, in spite of its +disadvantages, of the dirigible airship. + +This is a hard saying for such of the aeroplane industry as survived +the War period and consolidated itself, and it is but the saying of a +section which bases its belief on the fact that, as was noted in the +very early years of the century, the aeroplane is primarily a war +machine. Moreover, the experience of the War period tended to discredit +the dirigible, since, before the introduction of helium gas, +the inflammability of its buoyant factor placed it at an immense +disadvantage beside the machine dependent on the atmosphere itself for +its lift. + +As life runs to-day, it is a long time since Kipling wrote his story of +the airways of a future world and thrust out a prophecy that the bulk +of the world's air traffic would be carried by gas-bag vessels. If the +school which inclines to belief in the dirigible is right in its belief, +as it well may be, then the foresight was uncannily correct, not only +in the matter of the main assumption, but in the detail with which the +writer embroidered it. + +On the constructional side, the history of the aeroplane is still so +much in the making that any attempt at a critical history would be +unwise, and it is possible only to record fact, leaving it to the future +for judgment to be passed. But, in a general way, criticism may +be advanced with regard to the place that aeronautics takes in +civilisation. In the past hundred years, the world has made miraculously +rapid strides materially, but moral development has not kept abreast. +Conception of the responsibilities of humanity remains virtually in a +position of a hundred years ago; given a higher conception of life and +its responsibilities, the aeroplane becomes the crowning achievement +of that long series which James Watt inaugurated, the last step in +intercommunication, the chain with which all nations are bound in +a growing prosperity, surely based on moral wellbeing. Without such +conception of the duties as well as the rights of life, this last +achievement of science may yet prove the weapon that shall end +civilisation as men know it to-day, and bring this ultra-material age to +a phase of ruin on which saner people can build a world more reasonable +and less given to groping after purely material advancement. + + + + +PART II. 1903-1920: PROGRESS IN DESIGN + +By Lieut.-Col. W. Lockwood Marsh + + + + +I. THE BEGINNINGS + +Although the first actual flight of an aeroplane was made by the Wrights +on December 17th 1903, it is necessary, in considering the progress +of design between that period and the present day, to go back to +the earlier days of their experiments with 'gliders,' which show the +alterations in design made by them in their step-bystep progress to a +flying machine proper, and give a clear idea of the stage at which they +had arrived in the art of aeroplane design at the time of their first +flights. + +They started by carefully surveying the work of previous experimenters, +such as Lilienthal and Chanute, and from the lesson of some of the +failures of these pioneers evolved certain new principles which were +embodied in their first glider, built in 1900. In the first place, +instead of relying upon the shifting of the operator's body to obtain +balance, which had proved too slow to be reliable, they fitted in front +of the main supporting surfaces what we now call an 'elevator,' which +could be flexed, to control the longitudinal balance, from where the +operator lay prone upon the main supporting surfaces. The second +main innovation which they incorporated in this first glider, and the +principle of which is still used in every aeroplane in existence, was +the attainment of lateral balance by warping the extremities of the main +planes. The effect of warping or pulling down the extremity of the wing +on one side was to increase its lift and so cause that side to rise. In +the first two gliders this control was also used for steering to right +and left. Both these methods of control were novel for other than model +work, as previous experimenters, such as Lilienthal and Pilcher, had +relied entirely upon moving the legs or shifting the position of the +body to control the longitudinal and lateral motions of their gliders. +For the main supporting surfaces of the glider the biplane system of +Chanute's gliders was adopted with certain modifications, while the +curve of the wings was founded upon the calculations of Lilienthal as to +wind pressure and consequent lift of the plane. + +This first glider was tested on the Kill Devil Hill sand-hills in North +Carolina in the summer of 1900 and proved at any rate the correctness +of the principles of the front elevator and warping wings, though its +designers were puzzled by the fact that the lift was less than they +expected; whilst the 'drag'(as we call it), or resistance, was also +considerably lower than their predictions. The 1901 machine was, in +consequence, nearly doubled in area--the lifting surface being increased +from 165 to 308 square feet--the first trial taking place on July 27th, +1901, again at Kill Devil Hill. It immediately appeared that something +was wrong, as the machine dived straight to the ground, and it was only +after the operator's position had been moved nearly a foot back from +what had been calculated as the correct position that the machine would +glide--and even then the elevator had to be used far more strongly than +in the previous year's glider. After a good deal of thought the apparent +solution of the trouble was finally found. + +This consisted in the fact that with curved surfaces, while at large +angles the centre of pressure moves forward as the angle decreases, when +a certain limit of angle is reached it travels suddenly backwards and +causes the machine to dive. The Wrights had known of this tendency from +Lilienthal's researches, but had imagined that the phenomenon would +disappear if they used a fairly lightly cambered--or curved--surface +with a very abrupt curve at the front. Having discovered what appeared +to be the cause they surmounted the difficulty by 'trussing down' the +camber of the wings, with the result that they at once got back to +the old conditions of the previous year and could control the machine +readily with small movements of the elevator, even being able to follow +undulations in the ground. They still found, however, that the lift was +not as great as it should have been; while the drag remained, as in +the previous glider, surprisingly small. This threw doubt on previous +figures as to wind resistance and pressure on curved surfaces; but +at the same time confirmed (and this was a most important result) +Lilienthal's previously questioned theory that at small angles the +pressure on a curved surface instead of being normal, or at right angles +to, the chord is in fact inclined in front of the perpendicular. The +result of this is that the pressure actually tends to draw the machine +forward into the wind--hence the small amount of drag, which had puzzled +Wilbur and Orville Wright. + +Another lesson which was learnt from these first two years of +experiment, was that where, as in a biplane, two surfaces are superposed +one above the other, each of them has somewhat less lift than it would +have if used alone. The experimenters were also still in doubt as to the +efficiency of the warping method of controlling the lateral balance +as it gave rise to certain phenomena which puzzled them, the machine +turning towards the wing having the greater angle, which seemed also to +touch the ground first, contrary to their expectations. Accordingly, +on returning to Dayton towards the end of 1901, they set themselves to +solve the various problems which had appeared and started on a +lengthy series of experiments to check the previous figures as to wind +resistance and lift of curved surfaces, besides setting themselves +to grapple with the difficulty of lateral control. They accordingly +constructed for themselves at their home in Dayton a wind tunnel 16 +inches square by 6 feet long in which they measured the lift and 'drag' +of more than two hundred miniature wings. In the course of these tests +they for the first time produced comparative results of the lift of +oblong and square surfaces, with the result that they re-discovered the +importance of 'aspect ratio'--the ratio of length to breadth of planes. +As a result, in the next year's glider the aspect ration of the wings +was increased from the three to one of the earliest model to about six +to one, which is approximately the same as that used in the machines +of to-day. Further than that, they discussed the question of lateral +stability, and came to the conclusion that the cause of the trouble was +that the effect of warping down one wing was to increase the resistance +of, and consequently slow down, that wing to such an extent that its +lift was reduced sufficiently to wipe out the anticipated increase in +lift resulting from the warping. From this they deduced that if the +speed of the warped wing could be controlled the advantage of increasing +the angle by warping could be utilised as they originally intended. +They therefore decided to fit a vertical fin at the rear which, if the +machine attempted to turn, would be exposed more and more to the wind +and so stop the turning motion by offering increased resistance. + +As a result of this laboratory research work the third Wright glider, +which was taken to Kill Devil Hill in September, 1902, was far more +efficient aerodynamically than either of its two predecessors, and was +fitted with a fixed vertical fin at the rear in addition to the movable +elevator in front. According to Mr Griffith Brewer,[*] this third glider +contained 305 square feet of surface; though there may possibly be a +mistake here, as he states[**] the surface of the previous year's glider +to have been only 290 square feet, whereas Wilbur Wright himself[***] +states it to have been 308 square feet. The matter is not, perhaps, save +historically, of much importance, except that the gliders are believed +to have been progressively larger, and therefore if we accept Wilbur +Wright's own figure of the surface of the second glider, the third +must have had a greater area than that given by Mr Griffith Brewer. +Unfortunately, no evidence of the Wright Brothers themselves on this +point is available. + +[*] Fourth Wilbur Wright Memorial Lecture, Aeronautical Journal, Vol. +XX, No. 79, page 75. + +[**] Ibid. page 73. + +[***] Ibid. pp. 91 and 102. + +The first glide of the 1902, season was made on September 17th of that +year, and the new machine at once showed itself an improvement on its +predecessors, though subsequent trials showed that the difficulty +of lateral balance had not been entirely overcome. It was decided, +therefore, to turn the vertical fin at the rear into a rudder by making +it movable. At the same time it was realised that there was a definite +relation between lateral balance and directional control, and the rudder +controls and wing-warping wires were accordingly connected This ended +the pioneer gliding experiments of Wilbur and Orville Wright--though +further glides were made in subsequent years--as the following year, +1903, saw the first power-driven machine leave the ground. + +To recapitulate--in the course of these original experiments the Wrights +confirmed Lilienthal's theory of the reversal of the centre of pressure +on cambered surfaces at small angles of incidence: they confirmed the +importance of high aspect ratio in respect to lift: they had evolved new +and more accurate tables of lift and pressure on cambered surfaces: +they were the first to use a movable horizontal elevator for controlling +height: they were the first to adjust the wings to different angles of +incidence to maintain lateral balance: and they were the first to use +the movable rudder and adjustable wings in combination. + +They now considered that they had gone far enough to justify them in +building a power-driven 'flier,' as they called their first aeroplane. +They could find no suitable engine and so proceeded to build for +themselves an internal combustion engine, which was designed to give +8 horse-power, but when completed actually developed about 12-15 +horse-power and weighed 240 lbs. The complete machine weighed about +750 lbs. Further details of the first Wright aeroplane are difficult to +obtain, and even those here given should be received with some caution. +The first flight was made on December 17th 1903, and lasted 12 seconds. +Others followed immediately, and the fourth lasted 59 seconds, a +distance of 852 feet being covered against a 20-mile wind. + +The following year they transferred operations to a field outside +Dayton, Ohio (their home), and there they flew a somewhat larger and +heavier machine with which on September 20th 1904, they completed the +first circle in the air. In this machine for the first time the pilot +had a seat; all the previous experiments having been carried out with +the operator lying prone on the lower wing. This was followed next +year by another still larger machine, and on it they carried out many +flights. During the course of these flights they satisfied themselves as +to the cause of a phenomenon which had puzzled them during the previous +year and caused them to fear that they had not solved the problem +of lateral control. They found that on occasions--always when on a +turn--the machine began to slide down towards the ground and that no +amount of warping could stop it. Finally it was found that if the nose +of the machine was tilted down a recovery could be effected; from which +they concluded that what actually happened was that the machine, 'owing +to the increased load caused by centrifugal force,' had insufficient +power to maintain itself in the air and therefore lost speed until a +point was reached at which the controls became inoperative. In other +words, this was the first experience of 'stalling on a turn,' which is a +danger against which all embryo pilots have to guard in the early stages +of their training. + +The 1905 machine was, like its predecessors, a biplane with a biplane +elevator in front and a double vertical rudder in rear. The span was 40 +feet, the chord of the wings being 6 feet and the gap between them about +the same. The total area was about 600 square feet which supported +a total weight of 925 lbs.; while the motor was 12 to 15 horse-power +driving two propellers on each side behind the main planes through +chains and giving the machine a speed of about 30 m.p.h. one of +these chains was crossed so that the propellers revolved in opposite +directions to avoid the torque which it was feared would be set up +if they both revolved the same way. The machine was not fitted with a +wheeled undercarriage but was carried on two skids, which also acted as +outriggers to carry the elevator. Consequently, a mechanical method of +launching had to be evolved and the machine received initial velocity +from a rail, along which it was drawn by the impetus provided by the +falling of a weight from a wooden tower or 'pylon.' As a result of this +the Wright aeroplane in its original form had to be taken back to its +starting rail after each flight, and could not restart from the point of +alighting. Perhaps, in comparison with French machines of more or less +contemporary date (evolved on independent lines in ignorance of the +Americans' work), the chief feature of the Wright biplane of 1905 +was that it relied entirely upon the skill of the operator for its +stability; whereas in France some attempt was being made, although +perhaps not very successfully, to make the machine automatically stable +laterally. The performance of the Wrights in carrying a loading of some +60 lbs. per horse-power is one which should not be overlooked. The wing +loading was about 1 1/2 lbs. per square foot. + +About the same time that the Wrights were carrying out their +power-driven experiments, a band of pioneers was quite independently +beginning to approach success in France. In practically every case, +however, they started from a somewhat different standpoint and took +as their basic idea the cellular (or box) kite. This form of kite, +consisting of two superposed surfaces connected at each end by a +vertical panel or curtain of fabric, had proved extremely successful for +man-carrying purposes, and, therefore, it was little wonder that several +minds conceived the idea of attempting to fly by fitting a series +of box-kites with an engine. The first to achieve success was M. +Santos-Dumont, the famous Brazilian pioneer-designer of airships, who, +on November 12th, 1906, made several flights, the last of which covered +a little over 700 feet. Santos-Dumont's machine consisted essentially of +two box-kites, forming the main wings, one on each side of the body, in +which the pilot stood, and at the front extremity of which was another +movable box-kite to act as elevator and rudder. The curtains at the ends +were intended to give lateral stability, which was further ensured by +setting the wings slightly inclined upwards from the centre, so that +when seen from the front they formed a wide V. This feature is still +to be found in many aeroplanes to-day and has come to be known as the +'dihedral.' The motor was at first of 24 horse-power, for which later a +50 horse-power Antoinette engine was substituted; whilst a three-wheeled +undercarriage was provided, so that the machine could start without +external mechanical aid. The machine was constructed of bamboo and +steel, the weight being as low as 352 lbs. The span was 40 feet, the +length being 33 feet, with a total surface of main planes of 860 square +feet. It will thus be seen--for comparison with the Wright machine--that +the weight per horse-power (with the 50 horse-power engine) was only 7 +lbs., while the wing loading was equally low at 1/2 lb. per square foot. + +The main features of the Santos-Dumont machine were the box-kite form of +construction, with a dihedral angle on the main planes, and the forward +elevator which could be moved in any direction and therefore acted in +the same way as the rudder at the rear of the Wright biplane. It had a +single propeller revolving in the centre behind the wings and was fitted +with an undercarriage incorporated in the machine. + +The other chief French experimenters at this period were the Voisin +Freres, whose first two machines--identical in form--were sold to +Delagrange and H. Farman, which has sometimes caused confusion, the two +purchasers being credited with the design they bought. The Voisins, like +the Wrights, based their designs largely on the experimental work of +Lilienthal, Langley, Chanute, and others, though they also carried out +tests on the lifting properties of aerofoils in a wind tunnel of their +own. Their first machines, like those of Santos-Dumont, showed the +effects of experimenting with box-kites, some of which they had built +for M. Ernest Archdeacon in 1904. In their case the machine, which was +again a biplane, had, like both the others previously mentioned, an +elevator in front--though in this case of monoplane form--and, as in +the Wright, a rudder was fitted in rear of the main planes. The Voisins, +however, fitted a fixed biplane horizontal 'tail'--in an effort to +obtain a measure of automatic longitudinal stability--between the two +surfaces of which the single rudder worked. For lateral stability they +depended entirely on end curtains between the upper and lower +surfaces of both the main planes and biplane tail surfaces. They, like +Santos-Dumont, fitted a wheeled undercarriage, so that the machine +was self-contained. The Voisin machine, then, was intended to be +automatically stable in both senses; whereas the Wrights deliberately +produced a machine which was entirely dependent upon the pilot's +skill for its stability. The dimensions of the Voisin may be given for +comparative purposes, and were as follows: Span 33 feet with a chord +(width from back to front) of main planes of 6 1/2 feet, giving a total +area of 430 square feet. The 50 horse-power Antoinette engine, which +was enclosed in the body (or 'nacelle ') in the front of which the pilot +sat, drove a propeller behind, revolving between the outriggers carrying +the tail. The total weight, including Farman as pilot, is given as 1,540 +lbs., so that the machine was much heavier than either of the others; +the weight per horse-power being midway between the Santos-Dumont +and the Wright at 31 lbs. per square foot, while the wing loading was +considerably greater than either at 3 1/2 lbs. per square foot. The +Voisin machine was experimented with by Farman and Delagrange from about +June 1907 onwards, and was in the subsequent years developed by Farman; +and right up to the commencement of the War upheld the principles of +the box-kite method of construction for training purposes. The chief +modification of the original design was the addition of flaps (or +ailerons) at the rear extremities of the main planes to give lateral +control, in a manner analogous to the wing-warping method invented by +the Wrights, as a result of which the end curtains between the planes +were abolished. An additional elevator was fitted at the rear of the +fixed biplane tail, which eventually led to the discarding of the front +elevator altogether. During the same period the Wright machine came into +line with the others by the fitting of a wheeled undercarriage integral +with the machine. A fixed horizontal tail was also added to the rear +rudder, to which a movable elevator was later attached; and, finally, +the front elevator was done away with. It will thus be seen that having +started from the very different standpoints of automatic stability and +complete control by the pilot, the Voisin (as developed in the Farman) +and Wright machines, through gradual evolution finally resulted in +aeroplanes of similar characteristics embodying a modicum of both +features. + +Before proceeding to the next stage of progress mention should be made +of the experimental work of Captain Ferber in France. This officer +carried out a large number of experiments with gliders contemporarily +with the Wrights, adopting--like them--the Chanute biplane principle. He +adopted the front elevator from the Wrights, but immediately went a step +farther by also fitting a fixed tail in rear, which did not become a +feature of the Wright machine until some seven or eight years later. He +built and appeared to have flown a machine fitted with a motor in 1905, +and was commissioned to go to America by the French War Office on a +secret mission to the Wrights. Unfortunately, no complete account of his +experiments appears to exist, though it can be said that his work was at +least as important as that of any of the other pioneers mentioned. + + + + +II. MULTIPLICITY OF IDEAS + +In a review of progress such as this, it is obviously impossible, when +a certain stage of development has been reached, owing to the very +multiplicity of experimenters, to continue dealing in anything +approaching detail with all the different types of machines; and it is +proposed, therefore, from this point to deal only with tendencies, and +to mention individuals merely as examples of a class of thought rather +than as personalities, as it is often difficult fairly to allocate the +responsibility for any particular innovation. + +During 1907 and 1908 a new type of machine, in the monoplane, began to +appear from the workshops of Louis Bleriot, Robert Esnault-Pelterie, and +others, which was destined to give rise to long and bitter controversies +on the relative advantages of the two types, into which it is not +proposed to enter here; though the rumblings of the conflict are still +to be heard by discerning ears. Bleriot's early monoplanes had certain +new features, such as the location of the pilot, and in some cases the +engine, below the wing; but in general his monoplanes, particularly the +famous No. XI on which the first Channel crossing was made on July +25th, 1909, embodied the main principles of the Wright and Voisin +types, except that the propeller was in front of instead of behind the +supporting surfaces, and was, therefore, what is called a 'tractor' in +place of the then more conventional 'pusher.' Bleriot aimed at lateral +balance by having the tip of each wing pivoted, though he soon fell into +line with the Wrights and adopted the warping system. The main features +of the design of Esnault-Pelterie's monoplane was the inverted dihedral +(or kathedral as this was called in Mr S. F. Cody's British Army Biplane +of 1907) on the wings, whereby the tips were considerably lower than +the roots at the body. This was designed to give automatic lateral +stability, but, here again, conventional practice was soon adopted and +the R.E.P. monoplanes, which became well-known in this country through +their adoption in the early days by Messrs Vickers, were of the ordinary +monoplane design, consisting of a tractor propeller with wire-stayed +wings, the pilot being in an enclosed fuselage containing the engine in +front and carrying at its rear extremity fixed horizontal and vertical +surfaces combined with movable elevators and rudder. Constructionally, +the R.E.P. monoplane was of extreme interest as the body was constructed +of steel. The Antoinette monoplane, so ably flown by Latham, was another +very famous machine of the 1909-1910 period, though its performance were +frequently marred by engine failure; which was indeed the bugbear of all +these early experimenters, and it is difficult to say, after this lapse +of time, how far in many cases the failures which occurred, both in +performances and even in the actual ability to rise from the ground, +were due to defects in design or merely faults in the primitive engines +available. The Antoinette aroused admiration chiefly through its +graceful, birdlike lines, which have probably never been equalled; but +its chief interest for our present purpose lies in the novel method of +wing-staying which was employed. Contemporary monoplanes practically +all had their wings stayed by wires to a post in the centre above the +fuselage, and, usually, to the undercarriage below. In the Antoinette, +however, a king post was introduced half-way along the wing, from which +wires were carried to the ends of the wings and the body. This +was intended to give increased strength and permitted of a greater +wing-spread and consequently improved aspect ratio. The same system of +construction was adopted in the British Martinsyde monoplanes of two or +three years later. + +This period also saw the production of the first triplane, which was +built by A. V. Roe in England and was fitted with a J.A.P. engine of +only 9 horse-power--an amazing performance which remains to this day +unequalled. Mr Roe's triplane was chiefly interesting otherwise for +the method of maintaining longitudinal control, which was achieved +by pivoting the whole of the three main planes so that their angle +of incidence could be altered. This was the direct converse of the +universal practice of elevating by means of a subsidiary surface either +in front or rear of the main planes. + +Recollection of the various flying meetings and exhibitions which one +attended during the years from 1909 to 1911, or even 1912 are chiefly +notable for the fact that the first thought on seeing any new type of +machine was not as to what its 'performance'--in speed, lift, or what +not--would be; but speculation as to whether it would leave the ground +at all when eventually tried. This is perhaps the best indication of the +outstanding characteristic of that interim period between the time of +the first actual flights and the later period, commencing about 1912, +when ideas had become settled and it was at last becoming possible to +forecast on the drawing-board the performance of the completed machine +in the air. Without going into details, for which there is no space +here, it is difficult to convey the correct impression of the chaotic +state which existed as to even the elementary principles of aeroplane +design. All the exhibitions contained large numbers--one had almost +written a majority--of machines which embodied the most unusual features +and which never could, and in practice never did, leave the ground. +At the same time, there were few who were sufficiently hardy to say +certainly that this or that innovation was wrong; and consequently +dozens of inventors in every country were conducting isolated +experiments on both good and bad lines. All kinds of devices, mechanical +and otherwise, were claimed as the solution of the problem of stability, +and there was even controversy as to whether any measure of stability +was not undesirable; one school maintaining that the only safety lay +in the pilot having the sole say in the attitude of the machine at any +given moment, and fearing danger from the machine having any mind of +its own, so to speak. There was, as in most controversies, some right +on both sides, and when we come to consider the more settled period from +1912 to the outbreak of the War in 1914 we shall find how a compromise +was gradually effected. + +At the same time, however, though it was at the time difficult to pick +out, there was very real progress being made, and, though a number of +'freak' machines fell out by the wayside, the pioneer designers of those +days learnt by a process of trial and error the right principles to +follow and gradually succeeded in getting their ideas crystallised. + +In connection with stability mention must be made of a machine which +was evolved in the utmost secrecy by Mr J. W. Dunne in a remote part +of Scotland under subsidy from the War office. This type, which was +constructed in both monoplane and biplane form, showed that it was +in fact possible in 1910 and 1911 to design an aeroplane which could +definitely be left to fly itself in the air. One of the Dunne machines +was, for example flown from Farnborough to Salisbury Plain without any +control other than the rudder being touched; and on another occasion it +flew a complete circle with all controls locked automatically assuming +the correct bank for the radius of turn. The peculiar form of wing used, +the camber of which varied from the root to the tip, gave rise however, +to a certain loss in efficiency, and there was also a difficulty in the +pilot assuming adequate control when desired. Other machines designed to +be stable--such as the German Etrich and the British Weiss gliders and +Handley-Page monoplanes--were based on the analogy of a wing attached +to a certain seed found in Nature (the 'Zanonia' leaf), on the righting +effect of back-sloped wings combined with upturned (or 'negative') tips. +Generally speaking, however, the machines of the 1909-1912 period relied +for what automatic stability they had on the principle of the dihedral +angle, or flat V, both longitudinally and laterally. Longitudinally this +was obtained by setting the tail at a slightly smaller angle than the +main planes. + +The question of reducing the resistance by adopting 'stream-line' forms, +along which the air could flow uninterruptedly without the formation +of eddies, was not at first properly realised, though credit should be +given to Edouard Nieuport, who in 1909 produced a monoplane with a +very large body which almost completely enclosed the pilot and made the +machine very fast, for those days, with low horse-power. On one of these +machines C. T. Weyman won the Gordon-Bennett Cup for America in 1911 +and another put up a fine performance in the same race with only a 30 +horse-power engine. The subject, was however, early taken up by the +British Advisory Committee for Aeronautics, which was established by +the Government in 1909, and designers began to realise the importance +of streamline struts and fuselages towards the end of this transition +period. These efforts were at first not always successful and showed at +times a lack of understanding of the problems involved, but there was +a very marked improvement during the year 1912. At the Paris Aero Salon +held early in that year there was a notable variety of ideas on the +subject; whereas by the time of the one held in October designs had +considerably settled down, more than one exhibitor showing what were +called 'monocoque' fuselages completely circular in shape and having +very low resistance, while the same show saw the introduction of +rotating cowls over the propeller bosses, or 'spinners,' as they came to +be called during the War. A particularly fine example of stream-lining +was to be found in the Deperdussin monoplane on which Vedrines won +back the Gordon-Bennett Aviation Cup from America at a speed of 105.5 +m.p.h.--a considerable improvement on the 78 m.p.h. of the preceding +year, which was by no means accounted for by the mere increase in engine +power from 100 horse-power to 140 horse-power. This machine was the +first in which the refinement of 'stream-lining' the pilot's head, which +became a feature of subsequent racing machines, was introduced. This +consisted of a circular padded excresence above the cockpit immediately +behind the pilot's head, which gradually tapered off into the top +surface of the fuselage. The object was to give the air an uninterrupted +flow instead of allowing it to be broken up into eddies behind the +head of the pilot, and it also provided a support against the enormous +wind-pressure encountered. This true stream-line form of fuselage owed +its introduction to the Paulhan-Tatin 'Torpille' monoplane of the Paris +Salon of early 1917. Altogether the end of the year 1912 began to see +the disappearance of 'freak' machines with all sorts of original ideas +for the increase of stability and performance. Designs had by then +gradually become to a considerable extent standardised, and it had +become unusual to find a machine built which would fail to fly. The +Gnome engine held the field owing to its advantages, as the first of +the rotary type, in lightness and ease of fitting into the nose of a +fuselage. The majority of machines were tractors (propeller in front) +although a preference, which died down subsequently, was still shown for +the monoplane over the biplane. This year also saw a great increase +in the number of seaplanes, although the 'flying boat' type had only +appeared at intervals and the vast majority were of the ordinary +aeroplane type fitted with floats in place of the land undercarriage; +which type was at that time commonly called 'hydro-aeroplane.' The usual +horse power was 50--that of the smallest Gnome engine--although engines +of 100 to 140 horse-power were also fitted occasionally. The average +weight per horse-power varied from 18 to 25 lbs., while the wing-loading +was usually in the neighbourhood of 5 to 6 lbs. per square foot. The +average speed ranged from 65-75 miles per hour. + + + + +III. PROGRESS ON STANDARDISED LINES + +In the last section an attempt has been made to show how, during what +was from the design standpoint perhaps the most critical period, order +gradually became evident out of chaos, ill-considered ideas dropped out +through failure to make good, and, though there was still plenty of room +for improvement in details, the bulk of the aeroplanes showed a general +similarity in form and conception. There was still a great deal to be +learnt in finding the best form of wing section, and performances were +still low; but it had become definitely possible to say that flying had +emerged from the chrysalis stage and had become a science. The period +which now began was one of scientific development and improvement--in +performance, manoeuvrability, and general airworthiness and stability. + +The British Military Aeroplane Competition held in the summer of 1912 +had done much to show the requirements in design by giving possibly +the first opportunity for a definite comparison of the performance +of different machines as measured by impartial observers on standard +lines--albeit the methods of measuring were crude. These showed that a +high speed--for those days--of 75 miles an hour or so was attended by +disadvantages in the form of an equally fast low speed, of 50 miles per +hour or more, and generally may be said to have given designers an idea +what to aim for and in what direction improvements were required. In +fact, the most noticeable point perhaps of the machines of this time was +the marked manner in which a machine that was good in one respect +would be found to be wanting in others. It had not yet been possible +to combine several desirable attributes in one machine. The nearest +approach to this was perhaps to be found in the much discussed +Government B.E.2 machine, which was produced from the Royal Aircraft +Factory at Farnborough, in the summer of 1912. Though considerably +criticized from many points of view it was perhaps the nearest approach +to a machine of all-round efficiency that had up to that date appeared. +The climbing rate, which subsequently proved so important for military +purposes, was still low, seldom, if ever, exceeding 400 feet per minute; +while gliding angles (ratio of descent to forward travel over the ground +with engine stopped) little exceeded 1 in 8. + +The year 1912 and 1913 saw the subsequently all-conquering tractor +biplane begin to come into its own. This type, which probably originated +in England, and at any rate attained to its greatest excellence prior to +the War from the drawing offices of the Avro Bristol and Sopwith firms, +dealt a blow at the monoplane from which the latter never recovered. + +The two-seater tractor biplane produced by Sopwith and piloted by H. G. +Hawker, showed that it was possible to produce a biplane with at least +equal speed to the best monoplanes, whilst having the advantage of +greater strength and lower landing speeds. The Sopwith machine had a top +speed of over 80 miles an hour while landing as slowly as little more +than 30 miles an hour; and also proved that it was possible to carry 3 +passengers with fuel for 4 hours' flight with a motive power of only 80 +horse-power. This increase in efficiency was due to careful attention to +detail in every part, improved wing sections, clean fuselage-lines, and +simplified undercarriages. At the same time, in the early part of 1913 +a tendency manifested itself towards the four-wheeled undercarriage, +a pair of smaller wheels being added in front of the main wheels to +prevent overturning while running on the ground; and several designs of +oleo-pneumatic and steel-spring undercarriages were produced in place +of the rubber shock-absorber type which had up till then been almost +universal. + +These two statements as to undercarriage designs may appear to be +contradictory, but in reality they do not conflict as they both showed +a greater attention to the importance of good springing, combined with +a desire to avoid complication and a mass of struts and wires which +increased head resistance. + +The Olympia Aero Show of March, 1913, also produced a machine which, +although the type was not destined to prove the best for the purpose for +which it was designed, was of interest as being the first to be designed +specially for war purposes. This was the Vickers 'Gun-bus,' a 'pusher' +machine, with the propeller revolving behind the main planes between the +outriggers carrying the tail, with a seat right in front for a gunner +who was provided with a machine gun on a swivelling mount which had a +free field of fire in every direction forward. The device which proved +the death-blow for this type of aircraft during the war will be dealt +with in the appropriate place later, but the machine should not go +unrecorded. + +As a result of a number of accidents to monoplanes the Government +appointed a Committee at the end of 1912 to inquire into the causes of +these. The report which was presented in March, 1913, exonerated the +monoplane by coming to the conclusion that the accidents were not caused +by conditions peculiar to monoplanes, but pointed out certain +desiderata in aeroplane design generally which are worth recording. They +recommended that the wings of aeroplanes should be so internally braced +as to have sufficient strength in themselves not to collapse if the +external bracing wires should give way. The practice, more common in +monoplanes than biplanes, of carrying important bracing wires from +the wings to the undercarriage was condemned owing to the liability of +damage from frequent landings. They also pointed out the desirability of +duplicating all main wires and their attachments, and of using stranded +cable for control wires. Owing to the suspicion that one accident at +least had been caused through the tearing of the fabric away from the +wing, it was recommended that fabric should be more securely fastened to +the ribs of the wings, and that devices for preventing the spreading of +tears should be considered. In the last connection it is interesting to +note that the French Deperdussin firm produced a fabric wing-covering +with extra strong threads run at right-angles through the fabric at +intervals in order to limit the tearing to a defined area. + +In spite, however, of the whitewashing of the monoplane by the +Government Committee just mentioned, considerable stir was occasioned +later in the year by the decision of the War office not to order any +more monoplanes; and from this time forward until the War period the +British Army was provided exclusively with biplanes. Even prior to this +the popularity of the monoplane had begun to wane. At the Olympia +Aero Show in March, 1913, biplanes for the first time outnumbered the +'single-deckers'(as the Germans call monoplanes); which had the effect +of reducing the wing-loading. In the case of the biplanes exhibited +this averaged about 4 1/2 lbs. per square foot, while in the case of +the monoplanes in the same exhibition the lowest was 5 1/2 lbs., and +the highest over 8 1/2 lbs. per square foot of area. It may here be +mentioned that it was not until the War period that the importance +of loading per horse-power was recognised as the true criterion of +aeroplane efficiency, far greater interest being displayed in the amount +of weight borne per unit area of wing. + +An idea of the state of development arrived at about this time may be +gained from the fact that the Commandant of the Military Wing of the +Royal Flying Corps in a lecture before the Royal Aeronautical Society +read in February, 1913, asked for single-seater scout aeroplanes with +a speed of 90 miles an hour and a landing speed of 45 miles an hour--a +performance which even two years later would have been considered modest +in the extreme. It serves to show that, although higher performances +were put up by individual machines on occasion, the general development +had not yet reached the stage when such performances could be obtained +in machines suitable for military purposes. So far as seaplanes were +concerned, up to the beginning of 1913 little attempt had been made to +study the novel problems involved, and the bulk of the machines at the +Monaco Meeting in April, 1913, for instance, consisted of land machines +fitted with floats, in many cases of a most primitive nature, without +other alterations. Most of those which succeeded in leaving the water +did so through sheer pull of engine power; while practically all were +incapable of getting off except in a fair sea, which enabled the pilot +to jump the machine into the air across the trough between two waves. +Stability problems had not yet been considered, and in only one or two +cases was fin area added at the rear high up, to counterbalance the +effect of the floats low down in front. Both twin and single-float +machines were used, while the flying boat was only just beginning +to come into being from the workshops of Sopwith in Great Britain, +Borel-Denhaut in France, and Curtiss in America. In view of the +approaching importance of amphibious seaplanes, mention should be made +of the flying boat (or 'bat boat' as it was called, following +Rudyard Kipling) which was built by Sopwith in 1913 with a wheeled +landing-carriage which could be wound up above the bottom surface of the +boat so as to be out of the way when alighting on water. + +During 1913 the (at one time almost universal) practice originated by +the Wright Brothers, of warping the wings for lateral stability, began +to die out and the bulk of aeroplanes began to be fitted with flaps +(or 'ailerons') instead. This was a distinct change for the better, as +continually warping the wings by bending down the extremities of the +rear spars was bound in time to produce 'fatigue' in that member and +lead to breakage; and the practice became completely obsolete during the +next two or three years. + +The Gordon-Bennett race of September, 1913, was again won by a +Deperdussin machine, somewhat similar to that of the previous year, but +with exceedingly small wings, only 107 square feet in area. The shape +of these wings was instructive as showing how what, from the general +utility point of view, may be disadvantageous can, for a special +purpose, be turned to account. With a span of 21 feet, the chord was +5 feet, giving the inefficient 'aspect ratio' of slightly over 4 to +1 only. The object of this was to reduce the lift, and therefore the +resistance, to as low a point as possible. The total weight was 1,500 +lbs., giving a wing-loading of 14 lbs. per square foot--a hitherto +undreamt-of figure. The result was that the machine took an enormously +long run before starting; and after touching the ground on landing ran +for nearly a mile before stopping; but she beat all records by attaining +a speed of 126 miles per hour. Where this performance is mainly +interesting is in contrast to the machines of 1920, which with an even +higher speed capacity would yet be able to land at not more than 40 or +50 miles per hour, and would be thoroughly efficient flying machines. + +The Rheims Aviation Meeting, at which the Gordon-Bennett race was flown, +also saw the first appearance of the Morane 'Parasol' monoplane. The +Morane monoplane had been for some time an interesting machine as being +the only type which had no fixed surface in rear to give automatic +stability, the movable elevator being balanced through being hinged +about one-third of the way back from the front edge. This made the +machine difficult to fly except in the hands of experts, but it was +very quick and handy on the controls and therefore useful for racing +purposes. In the 'Parasol' the modification was introduced of raising +the wing above the body, the pilot looking out beneath it, in order to +give as good a view as possible. + +Before passing to the year 1914 mention should be made of the feat +performed by Nesteroff, a Russian, and Pegoud, a French pilot, who were +the first to demonstrate the possibilities of flying upside-down and +looping the loop. Though perhaps not coming strictly within the purview +of a chapter on design (though certain alterations were made to the top +wing-bracing of the machine for this purpose) this performance was +of extreme importance to the development of aviation by showing the +possibility of recovering, given reasonable height, from any position in +the air; which led designers to consider the extra stresses to which an +aeroplane might be subjected and to take steps to provide for them by +increasing strength where necessary. + +When the year 1914 opened a speed of 126 miles per hour had been +attained and a height of 19,600 feet had been reached. The Sopwith and +Avro (the forerunner of the famous training machine of the War period) +were probably the two leading tractor biplanes of the world, both +two-seaters with a speed variation from 40 miles per hour up to some +90 miles per hour with 80 horse-power engines. The French were still +pinning their faith mainly to monoplanes, while the Germans were +beginning to come into prominence with both monoplanes and biplanes of +the 'Taube' type. These had wings swept backward and also upturned +at the wing-tips which, though it gave a certain measure of automatic +stability, rendered the machine somewhat clumsy in the air, and their +performances were not on the whole as high as those of either France or +Great Britain. + +Early in 1914 it became known that the experimental work of Edward +Busk--who was so lamentably killed during an experimental flight later +in the year--following upon the researches of Bairstow and others had +resulted in the production at the Royal Aircraft Factory at Farnborough +of a truly automatically stable aeroplane. This was the 'R.E.' +(Reconnaissance Experimental), a development of the B.E. which has +already been referred to. The remarkable feature of this design was that +there was no particular device to which one could point out as the cause +of the stability. The stable result was attained simply by detailed +design of each part of the aeroplane, with due regard to its relation +to, and effect on, other parts in the air. Weights and areas were so +nicely arranged that under practically any conditions the machine tended +to right itself. It did not, therefore, claim to be a machine which it +was impossible to upset, but one which if left to itself would tend +to right itself from whatever direction a gust might come. When the +principles were extended to the 'B.E. 2c' type (largely used at the +outbreak of the War) the latter machine, if the engine were switched of +f at a height of not less than 1,000 feet above the ground, would after +a few moments assume its correct gliding angle and glide down to the +ground. + +The Paris Aero Salon of December, 1913, had been remarkable chiefly for +the large number of machines of which the chassis and bodywork had been +constructed of steel-tubing; for the excess of monoplanes over biplanes; +and (in the latter) predominance of 'pusher' machines (with propeller +in rear of the main planes) compared with the growing British preference +for 'tractors' (with air screw in front). Incidentally, the Maurice +Farman, the last relic of the old type box-kite with elevator in front +appeared shorn of this prefix, and became known as the 'short-horn' in +contradistinction to its front-elevatored predecessor which, owing to +its general reliability and easy flying capabilities, had long been +affectionately called the 'mechanical cow.' The 1913 Salon also saw +some lingering attempts at attaining automatic stability by pendulum and +other freak devices. + +Apart from the appearance of 'R.E.1,' perhaps the most notable +development towards the end of 1913 was the appearance of the Sopwith +'Tabloid 'tractor biplane. This single-seater machine, evolved from +the two-seater previously referred to, fitted with a Gnome engine of 80 +horse-power, had the, for those days, remarkable speed of 92 miles an +hour; while a still more notable feature was that it could remain in +level flight at not more than 37 miles per hour. This machine is of +particular importance because it was the prototype and forerunner of the +successive designs of single-seater scout fighting machines which were +used so extensively from 1914 to 1918. It was also probably the first +machine to be capable of reaching a height of 1,000 feet within one +minute. It was closely followed by the 'Bristol Bullet,' which was +exhibited at the Olympia Aero Show of March, 1914. This last pre-war +show was mainly remarkable for the good workmanship displayed--rather +than for any distinct advance in design. In fact, there was a notable +diversity in the types displayed, but in detailed design considerable +improvements were to be seen, such as the general adoption of stranded +steel cable in place of piano wire for the mail bracing. + + + + +IV. THE WAR PERIOD + +Up to this point an attempt has been made to give some idea of the +progress that was made during the eleven years that had elapsed since +the days of the Wrights' first flights. Much advance had been made and +aeroplanes had settled down, superficially at any rate, into more or +less standardised forms in three main types--tractor monoplanes, tractor +biplanes, and pusher biplanes. Through the application of the results +of experiments with models in wind tunnels to full-scale machines, +considerable improvements had been made in the design of wing sections, +which had greatly increased the efficiency of aeroplanes by raising the +amount of 'lift' obtained from the wing compared with the 'drag' (or +resistance to forward motion) which the same wing would cause. In the +same way the shape of bodies, interplane struts, etc., had been +improved to be of better stream-line shape, for the further reduction +of resistance; while the problems of stability were beginning to be +tolerably well understood. Records (for what they are worth) stood +at 21,000 feet as far as height was concerned, 126 miles per hour for +speed, and 24 hours duration. That there was considerable room for +development is, however, evidenced by a statement made by the late B. +C. Hucks (the famous pilot) in the course of an address delivered before +the Royal Aeronautical Society in July, 1914. 'I consider,' he said, +'that the present day standard of flying is due far more to the +improvement in piloting than to the improvement in machines.... I +consider those (early 1914) machines are only slight improvements on +the machines of three years ago, and yet they are put through evolutions +which, at that time, were not even dreamed of. I can take a good example +of the way improvement in piloting has outdistanced improvement in +machines--in the case of myself, my 'looping' Bleriot. Most of you know +that there is very little difference between that machine and the 50 +horse-power Bleriot of three years ago.' This statement was, of course, +to some extent an exaggeration and was by no means agreed with by +designers, but there was at the same time a germ of truth in it. There +is at any rate little doubt that the theory and practice of aeroplane +design made far greater strides towards becoming an exact science during +the four years of War than it had done during the six or seven years +preceding it. + +It is impossible in the space at disposal to treat of this development +even with the meagre amount of detail that has been possible while +covering the 'settling down' period from 1911 to 1914, and it is +proposed, therefore, to indicate the improvements by sketching briefly +the more noticeable difference in various respects between the average +machine of 1914 and a similar machine of 1918. + +In the first place, it was soon found that it was possible to obtain +greater efficiency and, in particular, higher speeds, from tractor +machines than from pusher machines with the air screw behind the main +planes. This was for a variety of reasons connected with the efficiency +of propellers and the possibility of reducing resistance to a greater +extent in tractor machines by using a 'stream-line' fuselage (or body) +to connect the main planes with the tail. Full advantage of this could +not be taken, however, owing to the difficulty of fixing a machine-gun +in a forward direction owing to the presence of the propeller. This was +finally overcome by an ingenious device (known as an 'Interrupter gear') +which allowed the gun to fire only when none of the propeller blades +was passing in front of the muzzle. The monoplane gradually fell into +desuetude, mainly owing to the difficulty of making that type adequately +strong without it becoming prohibitively heavy, and also because of its +high landing speed and general lack of manoeuvrability. The triplane +was also little used except in one or two instances, and, practically +speaking, every machine was of the biplane tractor type. + +A careful consideration of the salient features leading to maximum +efficiency in aeroplanes--particularly in regard to speed and climb, +which were the two most important military requirements--showed that +a vital feature was the reduction in the amount of weight lifted per +horse-power employed; which in 1914 averaged from 20 to 25 lbs. This was +effected both by gradual increase in the power and size of the engines +used and by great improvement in their detailed design (by increasing +compression ratio and saving weight whenever possible); with the result +that the motive power of single-seater aeroplanes rose from 80 and 100 +horse-power in 1914 to an average of 200 to 300 horse-power, while the +actual weight of the engine fell from 3 1/2-4 lbs. per horse-power to an +average of 2 1/2 lbs. per horse-power. This meant that while a pre-war +engine of 100 horse-power would weigh some 400 lbs., the 1918 engine +developing three times the power would have less than double the weight. +The result of this improvement was that a scout aeroplane at the time +of the Armistice would have 1 horse-power for every 8 lbs. of weight +lifted, compared with the 20 or 25 lbs. of its 1914 predecessors. This +produced a considerable increase in the rate of climb, a good postwar +machine being able to reach 10,000 feet in about 5 minutes and 20,000 +feet in under half an hour. The loading per square foot was also +considerably increased; this being rendered possible both by improvement +in the design of wing sections and by more scientific construction +giving increased strength. It will be remembered that in the machine +of the very early period each square foot of surface had only to lift +a weight of some 1 1/2 to 2 lbs., which by 1914 had been increased to +about 4 lbs. By 1918 aeroplanes habitually had a loading of 8 lbs. or +more per square foot of area; which resulted in great increase in speed. +Although a speed of 126 miles per hour had been attained by a specially +designed racing machine over a short distance in 1914, the average at +that period little exceeded, if at all, 100 miles per hour; whereas in +1918 speeds of 130 miles per hour had become a commonplace, and shortly +afterwards a speed of over 166 miles an hour was achieved. + +In another direction, also, that of size, great developments were made. +Before the War a few machines fitted with more than one engine had been +built (the first being a triple Gnome-engined biplane built by Messrs +Short Bros. at Eastchurch in 1913), but none of large size had been +successfully produced, the total weight probably in no case exceeding +about 2 tons. In 1916, however, the twin engine Handley-Page biplane +was produced, to be followed by others both in this country and abroad, +which represented a very great increase in size and, consequently, +load-carrying capacity. By the end of the War period several types were +in existence weighing a total of 10 tons when fully loaded, of which +some 4 tons or more represented 'useful load' available for crew, +fuel, and bombs or passengers. This was attained through very careful +attention to detailed design, which showed that the material could be +employed more efficiently as size increased, and was also due to the +fact that a large machine was not liable to be put through the same +evolutions as a small machine, and therefore could safely be built with +a lower factor of safety. Owing to the fact that a wing section which is +adopted for carrying heavy loads usually has also a somewhat low lift +to drag ratio, and is not therefore productive of high speed, these +machines are not as fast as light scouts; but, nevertheless, they proved +themselves capable of achieving speeds of 100 miles an hour or more in +some cases; which was faster than the average small machine of 1914. + +In one respect the development during the War may perhaps have proved +to be somewhat disappointing, as it might have been expected that great +improvements would be effected in metal construction, leading almost to +the abolition of wooden structures. Although, however, a good deal of +experimental work was done which resulted in overcoming at any rate the +worst of the difficulties, metal-built machines were little used (except +to a certain extent in Germany) chiefly on account of the need for rapid +production and the danger of delay resulting from switching over from +known and tried methods to experimental types of construction. +The Germans constructed some large machines, such as the giant +Siemens-Schukhert machine, entirely of metal except for the wing +covering, while the Fokker and Junker firms about the time of the +Armistice in 1918 both produced monoplanes with very deep all-metal +wings (including the covering) which were entirely unstayed externally, +depending for their strength on internal bracing. In Great Britain cable +bracing gave place to a great extent to 'stream-line wires,' which are +steel rods rolled to a more or less oval section, while tie-rods were +also extensively used for the internal bracing of the wings. Great +developments in the economical use of material were also made in the +direction of using built-up main spars for the wings and interplane +struts; spars composed of a series of layers (or 'laminations') of +different pieces of wood also being used. + +Apart from the metallic construction of aeroplanes an enormous amount +of work was done in the testing of different steels and light alloys for +use in engines, and by the end of the War period a number of aircraft +engines were in use of which the pistons and other parts were of such +alloys; the chief difficulty having been not so much in the design as in +the successful heat-treatment and casting of the metal. + +An important development in connection with the inspection and +testing of aircraft parts, particularly in the case of metal, was the +experimental application of X-ray photography, which showed up latent +defects, both in the material and in manufacture, which would otherwise +have passed unnoticed. This method was also used to test the penetration +of glue into the wood on each side of joints, so giving a measure of the +strength; and for the effect of 'doping' the wings, dope being a film +(of cellulose acetate dissolved in acetone with other chemicals) +applied to the covering of wings and bodies to render the linen taut and +weatherproof, besides giving it a smooth surface for the lessening of +'skin friction' when passing rapidly through the air. + +An important result of this experimental work was that it in many cases +enabled designers to produce aeroplane parts from less costly material +than had previously been considered necessary, without impairing the +strength. It may be mentioned that it was found undesirable to use +welded joints on aircraft in any part where the material is subjectto +a tensile or bending load, owing to the danger resulting from bad +workmanship causing the material to become brittle--an effect which +cannot be discovered except by cutting through the weld, which, of +course, involves a test to destruction. Written, as it has been, in +August, 1920, it is impossible in this chapter to give any conception of +how the developments of War will be applied to commercial aeroplanes, +as few truly commercial machines have yet been designed, and even those +still show distinct traces of the survival of war mentality. When, +however, the inevitable recasting of ideas arrives, it will become +evident, whatever the apparent modification in the relative importance +of different aspects of design, that enormous advances were made under +the impetus of War which have left an indelible mark on progress. + +We have, during the seventeen years since aeroplanes first took the air, +seen them grow from tentative experimental structures of unknown and +unknowable performance to highly scientific products, of which not +only the performances (in speed, load-carrying capacity, and climb) are +known, but of which the precise strength and degree of stability can be +forecast with some accuracy on the drawing board. For the rest, with +the future lies--apart from some revolutionary change in fundamental +design--the steady development of a now well-tried and well-found +engineering structure. + + + + +PART III. AEROSTATICS + + + + +I. BEGINNINGS + +Francesco Lana, with his 'aerial ship,' stands as one of the first great +exponents of aerostatics; up to the time of the Montgolfier and +Charles balloon experiments, aerostatic and aerodynamic research are so +inextricably intermingled that it has been thought well to treat of them +as one, and thus the work of Lana, Veranzio and his parachute, Guzman's +frauds, and the like, have already been sketched. In connection with +Guzman, Hildebrandt states in his Airships Past and Present, a +fairly exhaustive treatise on the subject up to 1906, the year of its +publication, that there were two inventors--or charlatans--Lorenzo de +Guzman and a monk Bartolemeo Laurenzo, the former of whom constructed +an unsuccessful airship out of a wooden basket covered with paper, +while the latter made certain experiments with a machine of which no +description remains. A third de Guzman, some twenty-five years later, +announced that he had constructed a flying machine, with which he +proposed to fly from a tower to prove his success to the public. The +lack of record of any fatal accident overtaking him about that time +seems to show that the experiment was not carried out. + +Galien, a French monk, published a book L'art de naviguer dans l'air +in 1757, in which it was conjectured that the air at high levels was +lighter than that immediately over the surface of the earth. Galien +proposed to bring down the upper layers of air and with them fill a +vessel, which by Archimidean principle would rise through the heavier +atmosphere. If one went high enough, said Galien, the air would be two +thousand times as light as water, and it would be possible to construct +an airship, with this light air as lifting factor, which should be as +large as the town of Avignon, and carry four million passengers with +their baggage. How this high air was to be obtained is matter for +conjecture--Galien seems to have thought in a vicious circle, in which +the vessel that must rise to obtain the light air must first be filled +with it in order to rise. + +Cavendish's discovery of hydrogen in 1776 set men thinking, and soon a +certain Doctor Black was suggesting that vessels might be filled with +hydrogen, in order that they might rise in the air. Black, however, did +not get beyond suggestion; it was Leo Cavallo who first made experiments +with hydrogen, beginning with filling soap bubbles, and passing on to +bladders and special paper bags. In these latter the gas escaped, +and Cavallo was about to try goldbeaters' skin at the time that the +Montgolfiers came into the field with their hot air balloon. + +Joseph and Stephen Montgolfier, sons of a wealthy French paper +manufacturer, carried out many experiments in physics, and Joseph +interested himself in the study of aeronautics some time before the +first balloon was constructed by the brothers--he is said to have made +a parachute descent from the roof of his house as early as 1771, but +of this there is no proof. Galien's idea, together with study of the +movement of clouds, gave Joseph some hope of achieving aerostation +through Galien's schemes, and the first experiments were made by passing +steam into a receiver, which, of course, tended to rise--but the +rapid condensation of the steam prevented the receiver from more than +threatening ascent. The experiments were continued with smoke, which +produced only a slightly better effect, and, moreover, the paper bag +into which the smoke was induced permitted of escape through its pores; +finding this method a failure the brothers desisted until Priestley's +work became known to them, and they conceived the use of hydrogen as +a lifting factor. Trying this with paper bags, they found that the +hydrogen escaped through the pores of the paper. + +Their first balloon, made of paper, reverted to the hot-air principle; +they lighted a fire of wool and wet straw under the balloon--and as a +matter of course the balloon took fire after very little experiment; +thereupon they constructed a second, having a capacity of 700 cubic +feet, and this rose to a height of over 1,000 feet. Such a success gave +them confidence, and they gave their first public exhibition on June +5th, 1783, with a balloon constructed of paper and of a circumference of +112 feet. A fire was lighted under this balloon, which, after rising to +a height of 1,000 feet, descended through the cooling of the air inside +a matter of ten minutes. At this the Academie des Sciences invited the +brothers to conduct experiments in Paris. + +The Montgolfiers were undoubtedly first to send up balloons, but other +experimenters were not far behind them, and before they could get to +Paris in response to their invitation, Charles, a prominent physicist of +those days, had constructed a balloon of silk, which he proofed against +escape of gas with rubber--the Roberts had just succeeded in dissolving +this substance to permit of making a suitable coating for the silk. With +a quarter of a ton of sulphuric acid, and half a ton of iron filings +and turnings, sufficient hydrogen was generated in four days to fill +Charles's balloon, which went up on August 28th, 1783. Although the day +was wet, Paris turned out to the number of over 300,000 in the Champs de +Mars, and cannon were fired to announce the ascent of the balloon. This, +rising very rapidly, disappeared amid the rain clouds, but, probably +bursting through no outlet being provided to compensate for the +escape of gas, fell soon in the neighbourhood of Paris. Here peasants, +ascribing evil supernatural influence to the fall of such a thing from +nowhere, went at it with the implements of their craft--forks, hoes, and +the like--and maltreated it severely, finally attaching it to a horse's +tail and dragging it about until it was mere rag and scrap. + +Meanwhile, Joseph Montgolfier, having come to Paris, set about the +construction of a balloon out of linen; this was in three diverse +sections, the top being a cone 30 feet in depth, the middle a cylinder +42 feet in diameter by 26 feet in depth, and the bottom another cone 20 +feet in depth from junction with the cylindrical portion to its point. +The balloon was both lined and covered with paper, decorated in blue and +gold. Before ever an ascent could be attempted this ambitious balloon +was caught in a heavy rainstorm which reduced its paper covering to pulp +and tore the linen at its seams, so that a supervening strong wind tore +the whole thing to shreds. + +Montgolfier's next balloon was spherical, having a capacity of 52,000 +cubic feet. It was made from waterproofed linen, and on September 19th, +1783, it made an ascent for the palace courtyard at Versailles, taking +up as passengers a cock, a sheep, and a duck. A rent at the top of the +balloon caused it to descend within eight minutes, and the duck and +sheep were found none the worse for being the first living things to +leave the earth in a balloon, but the cock, evidently suffering, was +thought to have been affected by the rarefaction of the atmosphere at +the tremendous height reached--for at that time the general opinion was +that the atmosphere did not extend more than four or five miles above +the earth's surface. It transpired later that the sheep had trampled on +the cock, causing more solid injury than any that might be inflicted by +rarefied air in an eight-minute ascent and descent of a balloon. + +For achieving this flight Joseph Montgolfier received from the King +of France a pension of of L40, while Stephen was given the order of St +Michael, and a patent of nobility was granted to their father. They were +made members of the Legion d'Honneur, and a scientific deputation, +of which Faujas de Saint-Fond, who had raised the funds with which +Charles's hydrogen balloon was constructed, presented to Stephen +Montgolfier a gold medal struck in honour of his aerial conquest. +Since Joseph appears to have had quite as much share in the success +as Stephen, the presentation of the medal to one brother only was in +questionable taste, unless it was intended to balance Joseph's pension. + +Once aerostation had been proved possible, many people began the +construction of small balloons--the wholehole thing was regarded as a +matter of spectacles and a form of amusement by the great majority. A +certain Baron de Beaumanoir made the first balloon of goldbeaters' skin, +this being eighteen inches in diameter, and using hydrogen as a lifting +factor. Few people saw any possibilities in aerostation, in spite of +the adventures of the duck and sheep and cock; voyages to the moon were +talked and written, and there was more of levity than seriousness over +ballooning as a rule. The classic retort of Benjamin Franklin stands +as an exception to the general rule: asked what was the use of +ballooning--'What's the use of a baby?' he countered, and the spirit of +that reply brought both the dirigible and the aeroplane to being, later. + +The next noteworthy balloon was one by Stephen Montgolfier, designed to +take up passengers, and therefore of rather large dimensions, as these +things went then. The capacity was 100,000 cubic feet, the depth being +85 feet, and the exterior was very gaily decorated. A short, cylindrical +opening was made at the lower extremity, and under this a fire-pan was +suspended, above the passenger car of the balloon. On October 15th, +1783, Pilatre de Rozier made the first balloon ascent--but the balloon +was held captive, and only allowed to rise to a height of 80 feet. But, +a little later in 1783, Rozier secured the honour of making the first +ascent in a free balloon, taking up with him the Marquis d'Arlandes. +It had been originally intended that two criminals, condemned to death, +should risk their lives in the perilous venture, with the prospect of +a free pardon if they made a safe descent, but d'Arlandes got the royal +consent to accompany Rozier, and the criminals lost their chance. Rozier +and d'Arlandes made a voyage lasting for twenty-five minutes, and, on +landing, the balloon collapsed with such rapidity as almost to suffocate +Rozier, who, however, was dragged out to safety by d'Arlandes. This +first aerostatic journey took place on November 21st, 1783. + +Some seven months later, on June 4th, 1784, a Madame Thible ascended in +a free balloon, reaching a height of 9,000 feet, and making a journey +which lasted for forty-five minutes--the great King Gustavus of Sweden +witnessed this ascent. France grew used to balloon ascents in the course +of a few months, in spite of the brewing of such a storm as might +have been calculated to wipe out all but purely political interests. +Meanwhile, interest in the new discovery spread across the Channel, +and on September 15th, 1784, one Vincent Lunardi made the first balloon +voyage in England, starting from the Artillery Ground at Chelsea, with +a cat and dog as passengers, and landing in a field in the parish of +Standon, near Ware. There is a rather rare book which gives a very +detailed account of this first ascent in England, one copy of which +is in the library of the Royal Aeronautical Society; the venturesome +Lunardi won a greater measure of fame through his exploit than did +Cody for his infinitely more courageous and--from a scientific point of +view--valuable first aeroplane ascent in this country. + +The Montgolfier type of balloon, depending on hot air for its lifting +power, was soon realised as having dangerous limitations. There was +always a possibility of the balloon catching fire while it was being +filled, and on landing there was further danger from the hot pan which +kept up the supply of hot air on the voyage--the collapsing balloon fell +on the pan, inevitably. The scientist Saussure, observing the filling of +the balloons very carefully, ascertained that it was rarefaction of the +air which was responsible for the lifting power, and not the heat in +itself, and, owing to the rarefaction of the air at normal temperature +at great heights above the earth, the limit of ascent for a balloon of +the Montgolfier type was estimated by him at under 9,000 feet. Moreover, +since the amount of fuel that could be carried for maintaining the +heat of the balloon after inflation was subject to definite limits, +prescribed by the carrying capacity of the balloon, the duration of the +journey was necessarily limited just as strictly. + +These considerations tended to turn the minds of those interested +in aerostation to consideration of the hydrogen balloon evolved by +Professor Charles. Certain improvements had been made by Charles +since his first construction; he employed rubber-coated silk in the +construction of a balloon of 30 feet diameter, and provided a net for +distributing the pressure uniformly over the surface of the envelope; +this net covered the top half of the balloon, and from its lower edge +dependent ropes hung to join on a wooden ring, from which the car of +the balloon was suspended--apart from the extension of the net so as to +cover in the whole of the envelope, the spherical balloon of to-day is +virtually identical with that of Charles in its method of construction. +He introduced the valve at the top of the balloon, by which escape of +gas could be controlled, operating his valve by means of ropes which +depended to the car of the balloon, and he also inserted a tube, of +about 7 inches diameter, at the bottom of the balloon, not only for +purposes of inflation, but also to provide a means of escape for gas in +case of expansion due to atmospheric conditions. + +Sulphuric acid and iron filings were used by Charles for filling his +balloon, which required three days and three nights for the generation +of its 14,000 cubic feet of hydrogen gas. The inflation was completed on +December 1st, 1783, and the fittings carried included a barometer and a +grapnel form of anchor. In addition to this, Charles provided the first +'ballon sonde' in the form of a small pilot balloon which he handed to +Montgolfier to launch before his own ascent, in order to determine the +direction and velocity of the wind. It was a graceful compliment to his +rival, and indicated that, although they were both working to the one +end, their rivalry was not a matter of bitterness. + +Ascending on December 1st, 1783, Charles took with him one of the +brothers Robert, and with him made the record journey up to that date, +covering a period of three and three-quarter hours, in which time they +journeyed some forty miles. Robert then landed, and Charles ascended +again alone, reaching such a height as to feel the effects of the +rarefaction of the air, this very largely due to the rapidity of his +ascent. Opening the valve at the top of the balloon, he descended +thirty-five minutes after leaving Robert behind, and came to earth a few +miles from the point of the first descent. His discomfort over the rapid +ascent was mainly due to the fact that, when Robert landed, he forgot to +compensate for the reduction of weight by taking in further ballast, +but the ascent proved the value of the tube at the bottom of the balloon +envelope, for the gas escaped very rapidly in that second ascent, and, +but for the tube, the balloon must inevitably have burst in the air, +with fatal results for Charles. + +As in the case of aeroplane flight, as soon as the balloon was proved +practicable the flight across the English Channel was talked of, and +Rozier, who had the honour of the first flight, announced his intention +of being first to cross. But Blanchard, who had an idea for a 'flying +car,' anticipated him, and made a start from Dover on January 7th, 1785, +taking with him an American doctor named Jeffries. Blanchard fitted out +his craft for the journey very thoroughly, taking provisions, oars, and +even wings, for propulsion in case of need. He took so much, in fact, +that as soon as the balloon lifted clear of the ground the whole of the +ballast had to be jettisoned, lest the balloon should drop into the sea. +Half-way across the Channel the sinking of the balloon warned Blanchard +that he had to part with more than ballast to accomplish the journey, +and all the equipment went, together with certain books and papers that +were on board the car. The balloon looked perilously like collapsing, +and both Blanchard and Jeffries began to undress in order further to +lighten their craft--Jeffries even proposed a heroic dive to save the +situation, but suddenly the balloon rose sufficiently to clear the +French coast, and the two voyagers landed at a point near Calais in +the Forest of Gaines, where a marble column was subsequently erected to +commemorate the great feat. + +Rozier, although not first across, determined to be second, and for +that purpose he constructed a balloon which was to owe its buoyancy to +a combination of the hydrogen and hot air principles. There was a +spherical hydrogen balloon above, and beneath it a cylindrical container +which could be filled with hot air, thus compensating for the leakage of +gas from the hydrogen portion of the balloon--regulating the heat of +his fire, he thought, would give him perfect control in the matter of +ascending and descending. + +On July 6th, 1785, a favourable breeze gave Rozier his opportunity of +starting from the French coast, and with a passenger aboard he cast off +in his balloon, which he had named the 'Aero-Montgolfiere.' There was a +rapid rise at first, and then for a time the balloon remained stationary +over the land, after which a cloud suddenly appeared round the balloon, +denoting that an explosion had taken place. Both Rozier and his +companion were killed in the fall, so that he, first to leave the earth +by balloon, was also first victim to the art of aerostation. + +There followed, naturally, a lull in the enthusiasm with which +ballooning had been taken up, so far as France was concerned. In Italy, +however, Count Zambeccari took up hot-air ballooning, using a spirit +lamp to give him buoyancy, and on the first occasion when the balloon +car was set on fire Zambeccari let down his passenger by means of the +anchor rope, and managed to extinguish the fire while in the air. This +reduced the buoyancy of the balloon to such an extent that it fell +into the Adriatic and was totally wrecked, Zambeccari being rescued by +fishermen. He continued to experiment up to 1812, when he attempted to +ascend at Bologna; the spirit in his lamp was upset by the collision +of the car with a tree, and the car was again set on fire. Zambeccari +jumped from the car when it was over fifty feet above level ground, and +was killed. With him the Rozier type of balloon, combining the hydrogen +and hot air principles, disappeared; the combination was obviously too +dangerous to be practical. + +The brothers Robert were first to note how the heat of the sun acted on +the gases within a balloon envelope, and it has since been ascertained +that sun rays will heat the gas in a balloon to as much as 80 degrees +Fahrenheit greater temperature than the surrounding atmosphere; +hydrogen, being less affected by change of temperature than coal gas, is +the most suitable filling element, and coal gas comes next as the medium +of buoyancy. This for the free and non-navigable balloon, though for the +airship, carrying means of combustion, and in military work liable to +ignition by explosives, the gas helium seems likely to replace hydrogen, +being non-combustible. + +In spite of the development of the dirigible airship, there remains +work for the free, spherical type of balloon in the scientific field. +Blanchard's companion on the first Channel crossing by balloon, Dr +Jeffries, was the first balloonist to ascend for purely scientific +purposes; as early as 1784 he made an ascent to a height of 9,000 feet, +and observed a fall in temperature of from degrees--at the level of +London, where he began his ascent--to 29 degrees at the maximum +height reached. He took up an electrometer, a hydrometer, a compass, a +thermometer, and a Toricelli barometer, together with bottles of water, +in order to collect samples of the air at different heights. In 1785 he +made a second ascent, when trigonometrical observations of the height of +the balloon were made from the French coast, giving an altitude of 4,800 +feet. + +The matter was taken up on its scientific side very early in America, +experiments in Philadelphia being almost simultaneous with those of the +Montgolfiers in France. The flight of Rozier and d'Arlandes inspired two +members of the Philadelphia Philosophical Academy to construct a balloon +or series of balloons of their own design; they made a machine which +consisted of no less than 47 small hydrogen balloons attached to a +wicker car, and made certain preliminary trials, using animals as +passengers. This was followed by a captive ascent with a man as +passenger, and eventually by the first free ascent in America, which +was undertaken by one James Wilcox, a carpenter, on December 28th, +1783. Wilcox, fearful of falling into a river, attempted to regulate his +landing by cutting slits in some of the supporting balloons, which was +the method adopted for regulating ascent or descent in this machine. +He first cut three, and then, finding that the effect produced was not +sufficient, cut three more, and then another five--eleven out of the +forty-seven. The result was so swift a descent that he dislocated his +wrist on landing. + + A NOTE ON BALLONETS OR AIR BAGS. + +Meusnier, toward the end of the eighteenth century, was first to +conceive the idea of compensating for the loss of gas due to expansion +by fitting to the interior of a free balloon a ballonet, or air bag, +which could be pumped full of air so as to retain the shape and rigidity +of the envelope. + +The ballonet became particularly valuable as soon as airship +construction became general, and it was in the course of advance +in Astra Torres design that the project was introduced of using the +ballonets in order to give inclination from the horizontal. In the +earlier Astra Torres, trimming was accomplished by moving the car fore +and aft--this in itself was an advance on the separate 'sliding weigh' +principle--and this was the method followed in the Astra Torres bought +by the British Government from France in 1912 for training airship +pilots. Subsequently, the two ballonets fitted inside the envelope were +made to serve for trimming by the extent of their inflation, and this +method of securing inclination proved the best until exterior rudders, +and greater engine power, supplanted it, as in the Zeppelin and, in +fact, all rigid types. + +In the kite balloon, the ballonet serves the purpose of a rudder, +filling itself through the opening being kept pointed toward the +wind--there is an ingenious type of air scoop with non-return valve +which assures perfect inflation. In the S.S. type of airship, two +ballonets are provided, the supply of air being taken from the propeller +draught by a slanting aluminium tube to the underside of the envelope, +where it meets a longitudinal fabric hose which connects the two +ballonet air inlets. In this hose the non-return air valves, known +as 'crab-pots,' are fitted, on either side of the junction with the +air-scoop. Two automatic air valves, one for each ballonet, are fitted +in the underside of the envelope, and, as the air pressure tends to +open these instead of keeping them shut, the spring of the valve is set +inside the envelope. Each spring is set to open at a pressure of 25 to +28 mm. + + + + +II. THE FIRST DIRIGIBLES + +Having got off the earth, the very early balloonists set about the task +of finding a means of navigating the air but, lacking steam or other +accessory power to human muscle, they failed to solve the problem. +Joseph Montgolfier speedily exploded the idea of propelling a balloon +either by means of oars or sails, pointing out that even in a dead +calm a speed of five miles an hour would be the limit achieved. Still, +sailing balloons were constructed, even up to the time of Andree, the +explorer, who proposed to retard the speed of the balloon by ropes +dragging on the ground, and then to spread a sail which should catch +the wind and permit of deviation of the course. It has been proved that +slight divergences from the course of the wind can be obtained by this +means, but no real navigation of the air could be thus accomplished. + +Professor Wellner, of Brunn, brought up the idea of a sailing balloon +in more practical fashion in 1883. He observed that surfaces inclined to +the horizontal have a slight lateral motion in rising and falling, and +deduced that by alternate lowering and raising of such surfaces he would +be able to navigate the air, regulating ascent and descent by increasing +or decreasing the temperature of his buoyant medium in the balloon. He +calculated that a balloon, 50 feet in diameter and 150 feet in length, +with a vertical surface in front and a horizontal surface behind, might +be navigated at a speed of ten miles per hour, and in actual tests at +Brunn he proved that a single rise and fall moved the balloon three +miles against the wind. His ideas were further developed by Lebaudy in +the construction of the early French dirigibles. + +According to Hildebrandt,[*] the first sailing balloon was built in 1784 +by Guyot, who made his balloon egg-shaped, with the smaller end at the +back and the longer axis horizontal; oars were intended to propel the +craft, and naturally it was a failure. Carra proposed the use of paddle +wheels, a step in the right direction, by mounting them on the sides +of the car, but the improvement was only slight. Guyton de Morveau, +entrusted by the Academy of Dijon with the building of a sailing +balloon, first used a vertical rudder at the rear end of his +construction--it survives in the modern dirigible. His construction +included sails and oars, but, lacking steam or other than human +propulsive power, the airship was a failure equally with Guyot's. + +[*] Airships Past and Present. + +Two priests, Miollan and Janinet, proposed to drive balloons through the +air by the forcible expulsion of the hot air in the envelope from the +rear of the balloon. An opening was made about half-way up the envelope, +through which the hot air was to escape, buoyancy being maintained by a +pan of combustibles in the car. Unfortunately, this development of the +Montgolfier type never got a trial, for those who were to be spectators +of the first flight grew exasperated at successive delays, and in the +end, thinking that the balloon would never rise, they destroyed it. + +Meusnier, a French general, first conceived the idea of compensating +for loss of gas by carrying an air bag inside the balloon, in order +to maintain the full expansion of the envelope. The brothers Robert +constructed the first balloon in which this was tried and placed the +air bag near the neck of the balloon which was intended to be driven +by oars, and steered by a rudder. A violent swirl of wind which was +encountered on the first ascent tore away the oars and rudder and broke +the ropes which held the air bag in position; the bag fell into the +opening of the neck and stopped it up, preventing the escape of gas +under expansion. The Duc de Chartres, who was aboard, realised the +extreme danger of the envelope bursting as the balloon ascended, and at +16,000 feet he thrust a staff through the envelope--another account says +that he slit it with his sword--and thus prevented disaster. The descent +after this rip in the fabric was swift, but the passengers got off +without injury in the landing. + +Meusnier, experimenting in various ways, experimented with regard to +the resistance offered by various shapes to the air, and found that an +elliptical shape was best; he proposed to make the car boat--shaped, in +order further to decrease the resistance, and he advocated an entirely +rigid connection between the car and the body of the balloon, as +indispensable to a dirigible.[*] He suggested using three propellers, +which were to be driven by hand by means of pulleys, and calculated that +a crew of eighty would be required to furnish sufficient motive power. +Horizontal fins were to be used to assure stability, and Meusnier +thoroughly investigated the pressures exerted by gases, in order to +ascertain the stresses to which the envelope would be subjected. More +important still, he went into detail with regard to the use of air bags, +in order to retain the shape of the balloon under varying pressures of +gas due to expansion and consequent losses; he proposed two separate +envelopes, the inner one containing gas, and the space between it and +the outer one being filled with air. Further, by compressing the air +inside the air bag, the rate of ascent or descent could be regulated. +Lebaudy, acting on this principle, found it possible to pump air at the +rate of 35 cubic feet per second, thus making good loss of ballast which +had to be thrown overboard. + +[*] Hildebrandt. + +Meusnier's balloon, of course, was never constructed, but his ideas have +been of value to aerostation up to the present time. His career ended +in the revolutionary army in 1793, when he was killed in the fighting +before Mayence, and the King of Prussia ordered all firing to cease +until Meusnier had been buried. No other genius came forward to carry +on his work, and it was realised that human muscle could not drive a +balloon with certainty through the air; experiment in this direction +was abandoned for nearly sixty years, until in 1852 Giffard brought the +first practicable power-driven dirigible to being. + +Giffard, inventor of the steam injector, had already made balloon +ascents when he turned to aeronautical propulsion, and constructed a +steam engine of 5 horsepower with a weight of only 100 lbs.--a great +achievement for his day. Having got his engine, he set about making the +balloon which it was to drive; this he built with the aid of two other +enthusiasts, diverging from Meusnier's ideas by making the ends pointed, +and keeping the body narrowed from Meusnier's ellipse to a shape more +resembling a rather fat cigar. The length was 144 feet, and the greatest +diameter only 40 feet, while the capacity was 88,000 cubic feet. A net +which covered the envelope of the balloon supported a spar, 66 feet in +length, at the end of which a triangular sail was placed vertically to +act as rudder. The car, slung 20 feet below the spar, carried the engine +and propeller. Engine and boiler together weighed 350 lbs., and drove +the 11 foot propeller at 110 revolutions per minute. + +As precaution against explosion, Giffard arranged wire gauze in front +of the stoke-hole of his boiler, and provided an exhaust pipe which +discharged the waste gases from the engine in a downward direction. With +this first dirigible he attained to a speed of between 6 and 8 feet per +second, thus proving that the propulsion of a balloon was a possibility, +now that steam had come to supplement human effort. + +Three years later he built a second dirigible, reducing the diameter and +increasing the length of the gas envelope, with a view to reducing air +resistance. The length of this was 230 feet, the diameter only 33 feet, +and the capacity was 113,000 cubic feet, while the upper part of the +envelope, to which the covering net was attached, was specially covered +to ensure a stiffening effect. The car of this dirigible was dropped +rather lower than that of the first machine, in order to provide more +thoroughly against the danger of explosions. Giffard, with a companion +named Yon as passenger, took a trial trip on this vessel, and made a +journey against the wind, though slowly. In commencing to descend, the +nose of the envelope tilted upwards, and the weight of the car and +its contents caused the net to slip, so that just before the dirigible +reached the ground, the envelope burst. Both Giffard and his companion +escaped with very slight injuries. + +Plans were immediately made for the construction of a third dirigible, +which was to be 1,970 feet in length, 98 feet in extreme diameter, and +to have a capacity of 7,800,000 cubic feet of gas. The engine of this +giant was to have weighed 30 tons, and with it Giffard expected to +attain a speed of 40 miles per hour. Cost prevented the scheme being +carried out, and Giffard went on designing small steam engines until his +invention of the steam injector gave him the funds to turn to dirigibles +again. He built a captive balloon for the great exhibition in London +in 1868, at a cost of nearly L30,000, and designed a dirigible balloon +which was to have held a million and three quarters cubic feet of gas, +carry two boilers, and cost about L40,000. The plans were thoroughly +worked out, down to the last detail, but the dirigible was never +constructed. Giffard went blind, and died in 1882--he stands as the +great pioneer of dirigible construction, more on the strength of the +two vessels which he actually built than on that of the ambitious later +conceptions of his brain. + +In 1872 Dupuy de Lome, commissioned by the French government, built a +dirigible which he proposed to drive by man-power--it was anticipated +that the vessel would be of use in the siege of Paris, but it was not +actually tested till after the conclusion of the war. The length of +this vessel was 118 feet, its greatest diameter 49 feet, the ends being +pointed, and the motive power was by a propeller which was revolved by +the efforts of eight men. The vessel attained to about the same speed as +Giffard's steam-driven airship; it was capable of carrying fourteen +men, who, apart from these engaged in driving the propeller, had to +manipulate the pumps which controlled the air bags inside the gas +envelope. + +In the same year Paul Haenlein, working in Vienna, produced an airship +which was a direct forerunner of the Lebaudy type, 164 feet in length, +30 feet greatest diameter, and with a cubic capacity of 85,000 feet. +Semi-rigidity was attained by placing the car as close to the envelope +as possible, suspending it by crossed ropes, and the motive power was +a gas engine of the Lenoir type, having four horizontal cylinders, and +giving about 5 horse-power with a consumption of about 250 cubic feet +of gas per hour. This gas was sucked from the envelope of the balloon, +which was kept fully inflated by pumping in compensating air to the air +bags inside the main envelope. A propeller, 15 feet in diameter, was +driven by the Lenoir engine at 40 revolutions per minute. This was the +first instance of the use of an internal combustion engine in connection +with aeronautical experiments. + +The envelope of this dirigible was rendered airtight by means of +internal rubber coating, with a thinner film on the outside. Coal gas, +used for inflation, formed a suitable fuel for the engine, but limited +the height to which the dirigible could ascend. Such trials as were made +were carried out with the dirigible held captive, and a speed of I 5 +feet per second was attained. Full experiment was prevented through +funds running low, but Haenlein's work constituted a distinct advance on +all that had been done previously. + +Two brothers, Albert and Gaston Tissandier, were next to enter the field +of dirigible construction; they had experimented with balloons during +the Franc-Prussian War, and had attempted to get into Paris by balloon +during the siege, but it was not until 1882 that they produced their +dirigible. + +This was 92 feet in length and 32 feet in greatest diameter, with +a cubic capacity of 37,500 feet, and the fabric used was varnished +cambric. The car was made of bamboo rods, and in addition to its crew +of three, it carried a Siemens dynamo, with 24 bichromate cells, each +of which weighed 17 lbs. The motor gave out 1 1/2 horse-power, which was +sufficient to drive the vessel at a speed of up to 10 feet per second. +This was not so good as Haenlein's previous attempt and, after L2,000 +had been spent, the Tissandier abandoned their experiments, since a +5-mile breeze was sufficient to nullify the power of the motor. + +Renard, a French officer who had studied the problem of dirigible +construction since 1878, associated himself first with a brother officer +named La Haye, and subsequently with another officer, Krebs, in the +construction of the second dirigible to be electrically-propelled. La +Haye first approached Colonel Laussedat, in charge of the Engineers of +the French Army, with a view to obtaining funds, but was refused, in +consequence of the practical failure of all experiments since 1870. +Renard, with whom Krebs had now associated himself, thereupon went to +Gambetta, and succeeded in getting a promise of a grant of L8,000 for +the work; with this promise Renard and Krebs set to work. + +They built their airship in torpedo shape, 165 feet in length, and of +just over 27 feet greatest diameter--the greatest diameter was at the +front, and the cubic capacity was 66,000 feet. The car itself was 108 +feet in length, and 4 1/2 feet broad, covered with silk over the bamboo +framework. The 23 foot diameter propeller was of wood, and was driven +by an electric motor connected to an accumulator, and yielding 8.5 +horsepower. The sweep of the propeller, which might have brought it in +contact with the ground in landing, was counteracted by rendering it +possible to raise the axis on which the blades were mounted, and a guide +rope was used to obviate damage altogether, in case of rapid descent. +There was also a 'sliding weight' which was movable to any required +position to shift the centre of gravity as desired. Altogether, with +passengers and ballast aboard, the craft weighed two tons. + +In the afternoon of August 8th, 1884, Renard and Krebs ascended in +the dirigible--which they had named 'La France,' from the military +ballooning ground at Chalais-Meudon, making a circular flight of about +five miles, the latter part of which was in the face of a slight +wind. They found that the vessel answered well to her rudder, and +the five-mile flight was made successfully in a period of 23 minutes. +Subsequent experimental flights determined that the air speed of the +dirigible was no less than 14 1/2 miles per hour, by far the best that +had so far been accomplished in dirigible flight. Seven flights in all +were made, and of these five were completely successful, the dirigible +returning to its starting point with no difficulty. On the other two +flights it had to be towed back. + +Renard attempted to repeat his construction on a larger scale, but funds +would not permit, and the type was abandoned; the motive power was not +sufficient to permit of more than short flights, and even to the present +time electric motors, with their necessary accumulators, are far too +cumbrous to compete with the self-contained internal combustion engine. +France had to wait for the Lebaudy brothers, just as Germany had to wait +for Zeppelin and Parseval. + +Two German experimenters, Baumgarten and Wolfert, fitted a Daimler motor +to a dirigible balloon which made its first ascent at Leipzig in 1880. +This vessel had three cars, and placing a passenger in one of the outer +cars[*] distributed the load unevenly, so that the whole vessel tilted +over and crashed to the earth, the occupants luckily escaping without +injury. After Baumgarten's death, Wolfert determined to carry on with +his experiments, and, having achieved a certain measure of success, he +announced an ascent to take place on the Tempelhofer Field, near Berlin, +on June 12th, 1897. The vessel, travelling with the wind, reached a +height of 600 feet, when the exhaust of the motor communicated flame to +the envelope of the balloon, and Wolfert, together with a passenger he +carried, was either killed by the fall or burnt to death on the ground. +Giffard had taken special precautions to avoid an accident of this +nature, and Wolfert, failing to observe equal care, paid the full +penalty. + +[*] Hildebrandt. + +Platz, a German soldier, attempting an ascent on the Tempelhofer Field +in the Schwartz airship in 1897, merely proved the dirigible a failure. +The vessel was of aluminium, 0.008 inch in thickness, strengthened by an +aluminium lattice work; the motor was two-cylindered petrol-driven; at +the first trial the metal developed such leaks that the vessel came +to the ground within four miles of its starting point. Platz, who was +aboard alone as crew, succeeded in escaping by jumping clear before the +car touched earth, but the shock of alighting broke up the balloon, and +a following high wind completed the work of full destruction. A second +account says that Platz, finding the propellers insufficient to drive +the vessel against the wind, opened the valve and descended too rapidly. + +The envelope of this dirigible was 156 feet in length, and the method +of filling was that of pushing in bags, fill them with gas, and then +pulling them to pieces and tearing them out of the body of the balloon. +A second contemplated method of filling was by placing a linen envelope +inside the aluminium casing, blowing it out with air, and then admitting +the gas between the linen and the aluminium outer casing. This would +compress the air out of the linen envelope, which was to be withdrawn +when the aluminium casing had been completely filled with gas. + +All this, however, assumes that the Schwartz type--the first rigid +dirigible, by the way--would prove successful. As it proved a failure on +the first trial, the problem of filling it did not arise again. + +By this time Zeppelin, retired from the German army, had begun to +devote himself to the study of dirigible construction, and, a year +after Schwartz had made his experiment and had failed, he got together +sufficient funds for the formation of a limitedliability company, and +started on the construction of the first of his series of airships. The +age of tentative experiment was over, and, forerunner of the success of +the heavier-than-air type of flying machine, successful dirigible flight +was accomplished by Zeppelin in Germany, and by Santos-Dumont in France. + + + + +III. SANTOS-DUMONT + +A Brazilian by birth, Santos-Dumont began in Paris in the year 1898 to +make history, which he subsequently wrote. His book, My Airships, is a +record of his eight years of work on lighter-than-air machines, a +period in which he constructed no less than fourteen dirigible balloons, +beginning with a cubic capacity of 6,350 feet, and an engine of 3 +horse-power, and rising to a cubic capacity of 71,000 feet on the tenth +dirigible he constructed, and an engine of 60 horse-power, which was +fitted to the seventh machine in order of construction, the one which he +built after winning the Deutsch Prize. + +The student of dirigible construction is recommended to Santos-Dumont's +own book not only as a full record of his work, but also as one of the +best stories of aerial navigation that has ever been written. Throughout +all his experiments, he adhered to the non-rigid type; his first +dirigible made its first flight on September 18th, 1898, starting from +the Jardin d'Acclimatation to the west of Paris; he calculated that his +3 horse-power engine would yield sufficient power to enable him to steer +clear of the trees with which the starting-point was surrounded, but, +yielding to the advice of professional aeronauts who were present, +with regard to the placing of the dirigible for his start, he tore the +envelope against the trees. Two days later, having repaired the balloon, +he made an ascent of 1,300 feet. In descending, the hydrogen left in +the balloon contracted, and Santos-Dumont narrowly escaped a serious +accident in coming to the ground. + +His second machine, built in the early spring of 1899, held over 7,000 +cubic feet of gas and gave a further 44 lbs. of ascensional force. The +balloon envelope was very long and very narrow; the first attempt at +flight was made in wind and rain, and the weather caused sufficient +contraction of the hydrogen for a wind gust to double the machine up and +toss it into the trees near its starting-point. The inventor immediately +set about the construction of 'Santos-Dumont No. 3,' on which he made a +number of successful flights, beginning on November 13th, 1899. On +the last of his flights, he lost the rudder of the machine and made a +fortunate landing at Ivry. He did not repair the balloon, considering +it too clumsy in form and its motor too small. Consequently No. 4 was +constructed, being finished on the 1st, August, 1900. It had a cubic +capacity of 14,800 feet, a length of 129 feet and greatest diameter +of 16.7 feet, the power plant being a 7 horse-power Buchet motor. +Santos-Dumont sat on a bicycle saddle fixed to the long bar suspended +under the machine, which also supported motor propeller, ballast; and +fuel. The experiment of placing the propeller at the stem instead of at +the stern was tried, and the motor gave it a speed of 100 revolutions +per minute. Professor Langley witnessed the trials of the machine, which +proved before the members of the International Congress of Aeronautics, +on September 19th, that it was capable of holding its own against a +strong wind. + +Finding that the cords with which his dirigible balloon cars were +suspended offered almost as much resistance to the air as did the +balloon itself, Santos-Dumont substituted piano wire and found that the +alteration constituted greater progress than many a more showy device. +He altered the shape and size of his No. 4 to a certain extent and +fitted a motor of 12 horse-power. Gravity was controlled by shifting +weights worked by a cord; rudder and propeller were both placed at the +stern. In Santos-Dumont's book there is a certain amount of confusion +between the No. 4 and No. 5 airships, until he explains that 'No. 5' +is the reconstructed 'No. 4.' It was with No. 5 that he won the +Encouragement Prize presented by the Scientific Commission of the Paris +Aero Club. This he devoted to the first aeronaut who between May and +October of 1900 should start from St Cloud, round the Eiffel Tower, +and return. If not won in that year, the prize was to remain open the +following year from May 1st to October 1st, and so on annually until +won. This was a simplification of the conditions of the Deutsch Prize +itself, the winning of which involved a journey of 11 kilometres in 30 +minutes. + +The Santos-Dumont No. 5, which was in reality the modified No. 4 with +new keel, motor, and propeller, did the course of the Deutsch Prize, +but with it Santos-Dumont made no attempt to win the prize until July of +1901, when he completed the course in 40 minutes, but tore his balloon +in landing. On the 8th August, with his balloon leaking, he made +a second attempt, and narrowly escaped disaster, the airship being +entirely wrecked. Thereupon he built No. 6 with a cubic capacity of +22,239 feet and a lifting power of 1,518 lbs. + +With this machine he won the Deutsch Prize on October 19th, 1901, +starting with the disadvantage of a side wind of 20 feet per second. He +reached the Eiffel Tower in 9 minutes and, through miscalculating his +turn, only just missed colliding with it. He got No. 6 under control +again and succeeded in getting back to his starting-point in 29 1/2 +minutes, thus winning the 125,000 francs which constituted the Deutsch +Prize, together with a similar sum granted to him by the Brazilian +Government for the exploit. The greater part of this money was given by +Santos-Dumont to charities. + +He went on building after this until he had made fourteen non-rigid +dirigibles; of these No. 12 was placed at the disposal of the military +authorities, while the rest, except for one that was sold to an American +and made only one trip, were matters of experiment for their maker. His +conclusions from his experiments may be gathered from his own work:-- + +'On Friday, 31st July, 1903, Commandant Hirschauer and +Lieutenant-Colonel Bourdeaux spent the afternoon with me at my airship +station at Neuilly St James, where I had my three newest airships--the +racing 'No. 7,' the omnibus 'No. 10,' and the runabout 'No. 9'--ready +for their study. Briefly, I may say that the opinions expressed by the +representatives of the Minister of War were so unreservedly favourable +that a practical test of a novel character was decided to be made. +Should the airship chosen pass successfully through it the result will +be conclusive of its military value. + +'Now that these particular experiments are leaving my exclusively +private control I will say no more of them than what has been already +published in the French press. The test will probably consist of an +attempt to enter one of the French frontier towns, such as Belfort or +Nancy, on the same day that the airship leaves Paris. It will not, +of course, be necessary to make the whole journey in the airship. A +military railway wagon may be assigned to carry it, with its balloon +uninflated, with tubes of hydrogen to fill it, and with all the +necessary machinery and instruments arranged beside it. At some station +a short distance from the town to be entered the wagon may be uncoupled +from the train, and a sufficient number of soldiers accompanying the +officers will unload the airship and its appliances, transport the whole +to the nearest open space, and at once begin inflating the balloon. +Within two hours from quitting the train the airship may be ready for +its flight to the interior of the technically-besieged town. + +'Such may be the outline of the task--a task presented imperiously to +French balloonists by the events of 1870-1, and which all the devotion +and science of the Tissandier brothers failed to accomplish. To-day +the problem may be set with better hope of success. All the essential +difficulties may be revived by the marking out of a hostile zone around +the town that must be entered; from beyond the outer edge of this zone, +then, the airship will rise and take its flight--across it. + +'Will the airship be able to rise out of rifle range? I have always +been the first to insist that the normal place of the airship is in low +altitudes, and I shall have written this book to little purpose if +I have not shown the reader the real dangers attending any brusque +vertical mounting to considerable heights. For this we have the terrible +Severo accident before our eyes. In particular, I have expressed +astonishment at hearing of experimenters rising to these altitudes +without adequate purpose in their early stages of experience with +dirigible balloons. All this is very different, however, from a +reasoned, cautious mounting, whose necessity has been foreseen and +prepared for.' + +Probably owing to the fact that his engines were not of sufficient +power, Santos-Dumont cannot be said to have solved the problem of the +military airship, although the French Government bought one of his +vessels. At the same time, he accomplished much in furthering and +inciting experiment with dirigible airships, and he will always rank +high among the pioneers of aerostation. His experiments might have +gone further had not the Wright brothers' success in America and French +interest in the problem of the heavier-than-air machine turned him from +the study of dirigibles to that of the aeroplane, in which also he takes +high rank among the pioneers, leaving the construction of a successful +military dirigible to such men as the Lebaudy brothers, Major Parseval, +and Zeppelin. + + + + +IV. THE MILITARY DIRIGIBLE + +Although French and German experiment in connection with the production +of an airship which should be suitable for military purposes proceeded +side by side, it is necessary to outline the development in the two +countries separately, owing to the differing character of the work +carried out. So far as France is concerned, experiment began with the +Lebaudy brothers, originally sugar refiners, who turned their energies +to airship construction in 1899. Three years of work went to the +production of their first vessel, which was launched in 1902, having +been constructed by them together with a balloon manufacturer named +Surcouf and an engineer, Julliot. The Lebaudy airships were what is +known as semi-rigids, having a spar which ran practically the full +length of the gas bag to which it was attached in such a way as to +distribute the load evenly. The car was suspended from the spar, at +the rear end of which both horizontal and vertical rudders were fixed, +whilst stabilising fins were provided at the stern of the gas envelope +itself. The first of the Lebaudy vessels was named the 'Jaune'; its +length was 183 feet and its maximum diameter 30 feet, while the cubic +capacity was 80,000 feet. The power unit was a 40 horse-power Daimler +motor, driving two propellers and giving a maximum speed of 26 miles +per hour. This vessel made 29 trips, the last of which took place in +November, 1902, when the airship was wrecked through collision with a +tree. + +The second airship of Lebaudy construction was 7 feet longer than the +first, and had a capacity of 94,000 cubic feet of gas with a triple air +bag of 17,500 cubic feet to compensate for loss of gas; this latter was +kept inflated by a rotary fan. The vessel was eventually taken over by +the French Government and may be counted the first dirigible airship +considered fit on its tests for military service. + +Later vessels of the Lebaudy type were the 'Patrie' and 'Republique,' +in which both size and method of construction surpassed those of the +two first attempts. The 'Patrie' was fitted with a 60 horse-power engine +which gave a speed of 28 miles an hour, while the vessel had a radius of +280 miles, carrying a crew of nine. In the winter of 1907 the 'Patrie' +was anchored at Verdun, and encountered a gale which broke her hold +on her mooring-ropes. She drifted derelict westward across France, the +Channel, and the British Isles, and was lost in the Atlantic. + +The 'Republique' had an 80 horse-power motor, which, however, only gave +her the same speed as the 'Patrie.' She was launched in July, 1908, +and within three months came to an end which constituted a tragedy +for France. A propeller burst while the vessel was in the air, and one +blade, flying toward the envelope, tore in it a great gash; the airship +crashed to earth, and the two officers and two non-commissioned officers +who were in the car were instantaneously killed. + +The Clement Bayard, and subsequently the Astra-Torres, non-rigids, +followed on the early Lebaudys and carried French dirigible construction +up to 1912. The Clement Bayard was a simple non-rigid having four lobes +at the stern end to assist stability. These were found to retard +the speed of the airship, which in the second and more successful +construction was driven by a Clement Bayard motor of 100 horse-power at +a speed of 30 miles an hour. On August 23rd, 1909, while being tried for +acceptance by the military authorities, this vessel achieved a record +by flying at a height of 5,000 feet for two hours. The Astra-Torres +non-rigids were designed by a Spaniard, Senor Torres, and built by the +Astra Company. The envelope was of trefoil shape, this being due to the +interior rigging from the suspension band; the exterior appearance +is that of two lobes side by side, overlaid by a third. The interior +rigging, which was adopted with a view to decreasing air resistance, +supports a low-hung car from the centre of the envelope; steering is +accomplished by means of horizontal planes fixed on the envelope at the +stern, and vertical planes depending beneath the envelope, also at the +stern end. + +One of the most successful of French pre-war dirigibles was a Clement +Bayard built in 1912. In this twin propellers were placed at the front +and horizontal and vertical rudders in a sort of box formation under the +envelope at the stern. The envelope was stream-lined, while the car of +the machine was placed well forward with horizontal controlling planes +above it and immediately behind the propellers. This airship, which +was named 'Dupuy de Lome,' may be ranked as about the most successful +non-rigid dirigible constructed prior to the War. + +Experiments with non-rigids in Germany was mainly carried on by Major +Parseval, who produced his first vessel in 1906. The main feature of +this airship consisted in variation in length of the suspension cables +at the will of the operator, so that the envelope could be given an +upward tilt while the car remained horizontal in order to give the +vessel greater efficiency in climbing. In this machine, the propeller +was placed above and forward of the car, and the controlling planes were +fixed directly to the envelope near the forward end. A second vessel +differed from the first mainly in the matter of its larger size, +variable suspension being again employed, together with a similar +method of control. The vessel was moderately successful, and under Major +Parseval's direction a third was constructed for passenger carrying, +with two engines of 120 horsepower, each driving propellers of 13 feet +diameter. This was the most successful of the early German dirigibles; +it made a number of voyages with a dozen passengers in addition to its +crew, as well as proving its value for military purposes by use as +a scout machine in manoeuvres. Later Parsevals were constructed +of stream-line form, about 300 feet in length, and with engines +sufficiently powerful to give them speeds up to 50 miles an hour. + +Major Von Gross, commander of a Balloon Battalion, produced semi-rigid +dirigibles from 1907 onward. The second of these, driven by two 75 +horse-power Daimler motors, was capable of a speed of 27 miles an hour; +in September of 1908 she made a trip from and back to Berlin which +lasted 13 hours, in which period she covered 176 miles with four +passengers and reached a height of 4,000 feet. Her successor, launched +in April of 1909, carried a wireless installation, and the next to this, +driven by four motors of 75 horse-power each, reached a speed of 45 +miles an hour. As this vessel was constructed for military purposes, +very few details either of its speed or method of construction were made +public. + +Practically all these vessels were discounted by the work of Ferdinand +von Zeppelin, who set out from the first with the idea of constructing +a rigid dirigible. Beginning in 1898, he built a balloon on an aluminium +framework covered with linen and silk, and divided into interior +compartments holding linen bags which were capable of containing nearly +400,000 cubic feet of hydrogen. The total length of this first Zeppelin +airship was 420 feet and the diameter 38 feet. Two cars were rigidly +attached to the envelope, each carrying a 16 horse-power motor, driving +propellers which were rigidly connected to the aluminium framework of +the balloon. Vertical and horizontal screws were used for lifting and +forward driving and a sliding weight was used to raise or lower the stem +of the vessel out of the horizontal in order to rise or descend without +altering the load by loss of ballast or the lift by loss of gas. + +The first trial of this vessel was made in July of 1900, and was +singularly unfortunate. The winch by which the sliding weight was +operated broke, and the balloon was so bent that the working of the +propellers was interfered with, as was the steering. A speed of 13 feet +per second was attained, but on descending, the airship ran against +some piles and was further damaged. Repairs were completed by the end +of September, 1900, and on a second trial flight made on October 21st a +speed of 30 feet per second was reached. + +Zeppelin was far from satisfied with the performance of this vessel, +and he therefore set about collecting funds for the construction of +a second, which was completed in 1905. By this time the internal +combustion engine had been greatly improved, and without any increase of +weight, Zeppelin was able to instal two motors of 85 horse-power each. +The total capacity was 367,000 cubic feet of hydrogen, carried in 16 gas +bags inside the framework, and the weight of the whole construction +was 9 tons--a ton less than that of the first Zeppelin airship. Three +vertical planes at front and rear controlled horizontal steering, while +rise and fall was controlled by horizontal planes arranged in box form. +Accident attended the first trial of this second airship, which took +place over the Bodensee on November 30th, 1905, 'It had been intended to +tow the raft, to which it was anchored, further from the shore against +the wind. But the water was too low to allow the use of the raft. The +balloon was therefore mounted on pontoons, pulled out into the lake, and +taken in tow by a motor-boat. It was caught by a strong wind which was +blowing from the shore, and driven ahead at such a rate that it +overtook the motor-boat. The tow rope was therefore at once cut, but it +unexpectedly formed into knots and became entangled with the airship, +pulling the front end down into the water. The balloon was then caught +by the wind and lifted into the air, when the propellers were set +in motion. The front end was at this instant pointing in a downward +direction, and consequently it shot into the water, where it was found +necessary to open the valves.'[*] + +[*] Hildebrandt, Airships Past and Present. + +The damage done was repaired within six weeks, and the second trial +was made on January 17th, 1906. The lifting force was too great for +the weight, and the dirigible jumped immediately to 1,500 feet. The +propellers were started, and the dirigible brought to a lower level, +when it was found possible to drive against the wind. The steering +arrangements were found too sensitive, and the motors were stopped, when +the vessel was carried by the wind until it was over land--it had been +intended that the trial should be completed over water. A descent was +successfully accomplished and the dirigible was anchored for the night, +but a gale caused it so much damage that it had to be broken up. It had +achieved a speed of 30 feet per second with the motors developing only +36 horse-power and, gathering from this what speed might have been +accomplished with the full 170 horse-power, Zeppelin set about the +construction of No. 3, with which a number of successful voyages were +made, proving the value of the type for military purposes. + +No. 4 was the most notable of the early Zeppelins, as much on account of +its disastrous end as by reason of any superior merit in comparison with +No. 3. The main innovation consisted in attaching a triangular keel to +the under side of the envelope, with two gaps beneath which the cars +were suspended. Two Daimler Mercedes motors of 110 horse-power each were +placed one in each car, and the vessel carried sufficient fuel for a +60-hour cruise with the motors running at full speed. Each motor drove a +pair of three-bladed metal propellers rigidly attached to the framework +of the envelope and about 15 feet in diameter. There was a vertical +rudder at the stern of the envelope and horizontal controlling planes +were fixed on the sides of the envelope. The best performances and the +end of this dirigible were summarised as follows by Major Squier:-- + +'Its best performances were two long trips performed during the summer +of 1908. The first, on July 4th, lasted exactly 12 hours, during which +time it covered a distance of 235 miles, crossing the mountains +to Lucerne and Zurich, and returning to the balloon-house near +Friedrichshafen, on Lake Constance. The average speed on this trip +was 32 miles per hour. On August 4th, this airship attempted a 24-hour +flight, which was one of the requirements made for its acceptance by the +Government. It left Friedrichshafen in the morning with the intention +of following the Rhine as far as Mainz, and then returning to its +starting-point, straight across the country. A stop of 3 hours 30 +minutes was made in the afternoon of the first day on the Rhine, to +repair the engine. On the return, a second stop was found necessary near +Stuttgart, due to difficulties with the motors, and some loss of gas. +While anchored to the ground, a storm arose which broke loose the +anchorage, and, as the balloon rose in the air, it exploded and took +fire (due to causes which have never been actually determined and +published) and fell to the ground, where it was completely destroyed. On +this journey, which lasted in all 31 hours 15 minutes, the airship was +in the air 20 hours 45 minutes, and covered a total distance of 378 +miles. + +'The patriotism of the German nation was aroused. Subscriptions were +immediately started, and in a short space of time a quarter of a million +pounds had been raised. A Zeppelin Society was formed to direct the +expenditure of this fund. Seventeen thousand pounds has been expended in +purchasing land near Friedrichshafen; workshops were erected, and it was +announced that within one year the construction of eight airships of the +Zeppelin type would be completed. Since the disaster to 'Zeppelin IV.' +the Crown Prince of Germany made a trip in 'Zeppelin No. 3,' which had +been called back into service, and within a very few days the German +Emperor visited Friedrichshafen for the purpose of seeing the airship in +flight. He decorated Count Zeppelin with the order of the Black Eagle. +German patriotism and enthusiasm has gone further, and the "German +Association for an Aerial Fleet" has been organised in sections +throughout the country. It announces its intention of building 50 +garages (hangars) for housing airships.' + +By January of 1909, with well over a quarter of a million in hand for +the construction of Zeppelin airships, No. 3 was again brought out, +probably in order to maintain public enthusiasm in respect of the +possible new engine of war. In March of that year No. 3 made a voyage +which lasted for 4 hours over and in the vicinity of Lake Constance; it +carried 26 passengers for a distance of nearly 150 miles. + +Before the end of March, Count Zeppelin determined to voyage from +Friedrichshafen to Munich, together with the crew of the airship and +four military officers. Starting at four in the morning and ascertaining +their route from the lights of railway stations and the ringing of bells +in the towns passed over, the journey was completed by nine o'clock, but +a strong south-west gale prevented the intended landing. The airship +was driven before the wind until three o'clock in the afternoon, when it +landed safely near Dingolfing; by the next morning the wind had fallen +considerably and the airship returned to Munich and landed on the parade +ground as originally intended. At about 3.30 in the afternoon, the +homeward journey was begun, Friedrichshafen being reached at about 7.30. + +These trials demonstrated that sufficient progress had been made to +justify the construction of Zeppelin airships for use with the German +army. No. 3 had been manoeuvred safely if not successfully in half a +gale of wind, and henceforth it was known as 'SMS. Zeppelin I.,' at the +bidding of the German Emperor, while the construction of 'SMS. Zeppelin +II.' was rapidly proceeded with. The fifth construction of Count +Zeppelin's was 446 feet in length, 42 1/2 feet in diameter, +and contained 530,000 cubic feet of hydrogen gas in 17 separate +compartments. Trial flights were made on the 26th May, 1909, and a week +later she made a record voyage of 940 miles, the route being from Lake +Constance over Ulm, Nuremberg, Leipzig, Bitterfeld, Weimar, Heilbronn, +and Stuttgart, descending near Goppingen; the time occupied in the +flight was upwards of 38 hours. + +In landing, the airship collided with a pear-tree, which damaged the +bows and tore open two sections of the envelope, but repairs on the +spot enabled the return journey to Friedrichshafen to be begun 24 hours +later. In spite of the mishap the Zeppelin had once more proved itself +as a possible engine of war, and thenceforth Germany pinned its faith +to the dirigible, only developing the aeroplane to such an extent as +to keep abreast of other nations. By the outbreak of war, nearly 30 +Zeppelins had been constructed; considerably more than half of these +were destroyed in various ways, but the experiments carried on with +each example of the type permitted of improvements being made. The first +fatality occurred in September, 1913, when the fourteenth Zeppelin to be +constructed, known as Naval Zeppelin L.1, was wrecked in the North Sea +by a sudden storm and her crew of thirteen were drowned. About three +weeks after this, Naval Zeppelin L.2, the eighteenth in order of +building, exploded in mid-air while manoeuvring over Johannisthal. She +was carrying a crew of 25, who were all killed. + +By 1912 the success of the Zeppelin type brought imitators. Chief among +them was the Schutte-Lanz, a Mannheim firm, which produced a rigid +dirigible with a wooden framework, wire braced. This was not a cylinder +like the Zeppelin, but reverted to the cigar shape and contained about +the same amount of gas as the Zeppelin type. The Schutte-Lanz was made +with two gondolas rigidly attached to the envelope in which the gas bags +were placed. The method of construction involved greater weight than was +the case with the Zeppelin, but the second of these vessels, built with +three gondolas containing engines, and a navigating cabin built into +the hull of the airship itself, proved quite successful as a naval scout +until wrecked on the islands off the coast of Denmark late in 1914. The +last Schutte-Lanz to be constructed was used by the Germans for raiding +England, and was eventually brought down in flames at Cowley. + + + + +V. BRITISH AIRSHIP DESIGN + +As was the case with the aeroplane, Great Britain left France and +Germany to make the running in the early days of airship construction; +the balloon section of the Royal Engineers was compelled to confine +its energies to work with balloons pure and simple until well after +the twentieth century had dawned, and such experiments as were made +in England were done by private initiative. As far back as 1900 Doctor +Barton built an airship at the Alexandra Palace and voyaged across +London in it. Four years later Mr E. T. Willows of Cardiff produced the +first successful British dirigible, a semi-rigid 74 feet in length and +18 feet in diameter, engined with a 7 horse-power Peugot twin-cylindered +motor. This drove a two-bladed propeller at the stern for propulsion, +and also actuated a pair of auxiliary propellers at the front which +could be varied in their direction so as to control the right and left +movements of the airship. This device was patented and the patent was +taken over by the British Government, which by 1908 found Mr Willow's +work of sufficient interest to regard it as furnishing data for +experiment at the balloon factory at Farnborough. In 1909, Willows +steered one of his dirigibles to London from Cardiff in a little less +than ten hours, making an average speed of over 14 miles an hour. The +best speed accomplished was probably considerably greater than this, +for at intervals of a few miles, Willows descended near the earth to +ascertain his whereabouts with the help of a megaphone. It must be added +that he carried a compass in addition to his megaphone. He set out for +Paris in November of 1910, reached the French coast, and landed near +Douai. Some damage was sustained in this landing, but, after repair, the +trip to Paris was completed. + +Meanwhile the Government balloon factory at Farnborough began airship +construction in 1907; Colonel Capper, R.E., and S. F. Cody were jointly +concerned in the production of a semi-rigid. Fifteen thicknesses of +goldbeaters' skin--about the most expensive covering obtainable--were +used for the envelope, which was 25 feet in diameter. A slight shower of +rain in which the airship was caught led to its wreckage, owing to the +absorbent quality of the goldbeaters' skin, whereupon Capper and Cody +set to work to reproduce the airship and its defects on a larger scale. +The first had been named 'Nulli Secundus' and the second was named +'Nulli Secundus II.' Punch very appropriately suggested that the first +vessel ought to have been named 'Nulli Primus,' while a possible third +should be christened 'Nulli Tertius.' 'Nulli Secundus II.' was fitted +with a 100 horse-power engine and had an envelope of 42 feet in +diameter, the goldbeaters' skin being covered in fabric and the car +being suspended by four bands which encircled the balloon envelope. +In October of 1907, 'Nulli Secundus II.' made a trial flight from +Farnborough to London and was anchored at the Crystal Palace. The wind +sprung up and took the vessel away from its mooring ropes, wrecking it +after the one flight. + +Stagnation followed until early in 1909, when a small airship fitted +with two 12 horse-power motors and named the 'Baby' was turned out from +the balloon factory. This was almost egg-shaped, the blunt end being +forward, and three inflated fins being placed at the tail as control +members. A long car with rudder and elevator at its rear-end carried +the engines and crew; the 'Baby' made some fairly successful flights and +gave a good deal of useful data for the construction of later vessels. + +Next to this was 'Army Airship 2A 'launched early in 1910 and larger, +longer, and narrower in design than the Baby. The engine was an 80 +horse-power Green motor which drove two pairs of propellers; small +inflated control members were fitted at the stern end of the envelope, +which was 154 feet in length. The suspended car was 84 feet long, +carrying both engines and crew, and the Willows idea of swivelling +propellers for governing the direction was used in this vessel. In June +of that year a new, small-type dirigible, the 'Beta,' was produced, +driven by a 30 horse-power Green engine with which she flew over 3,000 +miles. She was the most successful British dirigible constructed up to +that time, and her successor, the 'Gamma,' was built on similar lines. +The 'Gamma' was a larger vessel, however, produced in 1912, with flat, +controlling fins and rudder at the rear end of the envelope, and with +the conventional long car suspended at some distance beneath the gas +bag. By this time, the mooring mast, carrying a cap of which the concave +side fitted over the convex nose of the airship, had been originated. +The cap was swivelled, and, when attached to it, an airship was held +nose on to the wind, thus reducing by more than half the dangers +attendant on mooring dirigibles in the open. + +Private subscription under the auspices of the Morning Post got together +sufficient funds in 1910 for the purchase of a Lebaudy airship, which +was built in France, flown across the Channel, and presented to the Army +Airship Fleet. This dirigible was 337 feet long, and was driven by two +135 horse-power Panhard motors, each of which actuated two propellers. +The journey from Moisson to Aldershot was completed at a speed of 36 +miles an hour, but the airship was damaged while being towed into its +shed. On May of the following year, the Lebaudy was brought out for a +flight, but, in landing, the guide rope fouled in trees and sheds and +brought the airship broadside on to the wind; she was driven into some +trees and wrecked to such an exteent that rebuilding was considered an +impossibility. A Clement Bayard, bought by the army airship section, +became scrap after even less flying than had been accomplished by the +Lebaudy. + +In April of 1910, the Admiralty determined on a naval air service, +and set about the production of rigid airships which should be able to +compete with Zeppelins as naval scouts. The construction was entrusted +to Vickers, Ltd., who set about the task at their Barrow works and built +something which, when tested after a year's work, was found incapable +of lifting its own weight. This defect was remedied by a series of +alterations, and meanwhile the unofficial title of 'Mayfly' was given to +the vessel. + +Taken over by the Admiralty before she had passed any flying tests, +the 'Mayfly' was brought out on September 24th, 1911, for a trial trip, +being towed out from her shed by a tug. When half out from the shed, +the envelope was caught by a light cross-wind, and, in spite of the pull +from the tug, the great fabric broke in half, nearly drowning the crew, +who had to dive in order to get clear of the wreckage. + +There was considerable similarity in form, though not in performance, +between the Mayfly and the prewar Zeppelin. The former was 510 feet in +length, cylindrical in form, with a diameter of 48 feet, and divided +into 19 gas-bag compartments. The motive power consisted of two 200 +horse-power Wolseley engines. After its failure, the Naval Air Service +bought an Astra-Torres airship from France and a Parseval from Germany, +both of which proved very useful in the early days of the War, doing +patrol work over the Channel before the Blimps came into being. + +Early in 1915 the 'Blimp' or 'S.S.' type of coastal airship was evolved +in response to the demand for a vessel which could be turned out quickly +and in quantities. There was urgent demand, voiced by Lord Fisher, for +a type of vessel capable of maintaining anti-submarine patrol off the +British coasts, and the first S.S. airships were made by combining a +gasbag with the most available type of aeroplane fuselage and engine, +and fitting steering gear. The 'Blimp' consisted of a B.E. fuselage with +engine and geared-down propeller, and seating for pilot and observer, +attached to an envelope about 150 feet in length. With a speed of +between 35 and 40 miles an hour, the 'Blimp' had a cruising capacity of +about ten hours; it was fitted with wireless set, camera, machine-gun, +and bombs, and for submarine spotting and patrol work generally it +proved invaluable, though owing to low engine power and comparatively +small size, its uses were restricted to reasonably fair weather. For +work farther out at sea and in all weathers, airships known as the coast +patrol type, and more commonly as 'coastals,' were built, and later +the 'N.S.' or North Sea type, still larger and more weather-worthy, +followed. By the time the last year of the War came, Britain led the +world in the design of non-rigid and semi-rigid dirigibles. The 'S.S.' +or 'Blimp' had been improved to a speed of 50 miles an hour, carrying a +crew of three, and the endurance record for the type was 18 1/2 hours, +while one of them had reached a height of 10,000 feet. The North Sea +type of non-rigid was capable of travelling over 20 hours at full speed, +or forty hours at cruising speed, and the number of non-rigids belonging +to the British Navy exceeded that of any other country. + +It was owing to the incapacity--apparent or real--of the British +military or naval designers to produce a satisfactory rigid airship that +the 'N.S.' airship was evolved. The first of this type was produced +in 1916, and on her trials she was voted an unqualified success, in +consequence of which the building of several more was pushed on. The +envelope, of 360,000 cubic feet capacity, was made on the Astra-Torres +principle of three lobes, giving a trefoil section. The ship carried +four fins, to three of which the elevator and rudder flaps were +attached; petrol tanks were placed inside the envelope, under which +was rigged a long covered-in car, built up of a light steel tubular +framework 35 feet in length. The forward portion was covered with +duralumin sheeting, an aluminium alloy which, unlike aluminium itself, +is not affected by the action of sea air and water, and the remainder +with fabric laced to the framework. Windows and port-holes were provided +to give light to the crew, and the controls and navigating instruments +were placed forward, with the sleeping accommodation aft. The engines +were mounted in a power unit structure, separate from the car and +connected by wooden gang ways supported by wire cables. A complete +electrical installation of two dynamos and batteries for lights, +signalling lamps, wireless, telephones, etc., was carried, and the +motive power consisted of either two 250 horse-power Rolls-Royce engines +or two 240 horse-power Fiat engines. The principal dimensions of this +type are length 262 feet, horizontal diameter 56 feet 9 inches, vertical +diameter 69 feet 3 inches. The gross lift is 24,300 lbs. and the +disposable lift without crew, petrol, oil, and ballast 8,500 lbs. The +normal crew carried for patrol work was ten officers and men. This type +holds the record of 101 hours continuous flight on patrol duty. + +In the matter of rigid design it was not until 1913 that the British +Admiralty got over the fact that the 'Mayfly' would not, and decided on +a further attempt at the construction of a rigid dirigible. The +contract for this was signed in March of 1914; work was suspended in the +following February and begun again in July, 1915, but it was not until +January of 1917 that the ship was finished, while her trials were not +completed until March of 1917, when she was taken over by the Admiralty. +The details of the construction and trial of this vessel, known as 'No. +9,' go to show that she did not quite fill the contract requirements in +respect of disposable lift until a number of alterations had been made. +The contract specified that a speed of at least 45 miles per hour was to +be attained at full engine power, while a minimum disposable lift of 5 +tons was to be available for movable weights, and the airship was to +be capable of rising to a height of 2,000 feet. Driven by four Wolseley +Maybach engines of 180 horse-power each, the lift of the vessel was not +sufficient, so it was decided to remove the two engines in the after +car and replace them by a single engine of 250 horsepower. With this the +vessel reached the contract speed of 45 miles per hour with a cruising +radius of 18 hours, equivalent to 800 miles when the engines were +running at full speed. The vessel served admirably as a training +airship, for, by the time she was completed, the No. 23 class of rigid +airship had come to being, and thus No. 9 was already out of date. + +Three of the 23 class were completed by the end of 1917; it was +stipulated that they should be built with a speed of at least 55 miles +per hour, a minimum disposable lift of 8 tons, and a capability of +rising at an average rate of not less than 1,000 feet per minute to a +height of 3,000 feet. The motive power consisted of four 250 horse-power +Rolls-Royce engines, one in each of the forward and after cars and two +in a centre car. Four-bladed propellers were used throughout the ship. + +A 23X type followed on the 23 class, but by the time two ships had been +completed, this was practically obsolete. The No. 31 class followed the +23X; it was built on Schutte-Lanz lines, 615 feet in length, 66 feet +diameter, and a million and a half cubic feet capacity. The hull was +similar to the later types of Zeppelin in shape, with a tapering stern +and a bluff, rounded bow. Five cars each carrying a 250 horse-power +Rolls-Royce engine, driving a single fixed propeller, were fitted, and +on her trials R.31 performed well, especially in the matter of speed. +But the experiment of constructing in wood in the Schutte-Lanz way +adopted with this vessel resulted in failure eventually, and the type +was abandoned. + +Meanwhile, Germany had been pushing forward Zeppelin design +and straining every nerve in the improvement of rigid dirigible +construction, until L.33 was evolved; she was generally known as +a super-Zeppelin, and on September 24th, 1916, six weeks after her +launching, she was damaged by gun-fire in a raid over London, being +eventually compelled to come to earth at Little Wigborough in Essex. The +crew gave themselves up after having set fire to the ship, and though +the fabric was totally destroyed, the structure of the hull remained +intact, so that just as Germany was able to evolve the Gotha bomber from +the Handley-Page delivered at Lille, British naval constructors were able +to evolve the R.33 type of airship from the Zeppelin framework delivered +at Little Wigborough. Two vessels, R.33 and R.34, were laid down for +completion; three others were also put down for construction, but, while +R.33 and R.34 were built almost entirely from the data gathered from +the wrecked L.33, the three later vessels embody more modern design, +including a number of improvements, and more especially greater +disposable lift. It has been commented that while the British +authorities were building R.33 and R.34, Germany constructed 30 +Zeppelins on 4 slips, for which reason it may be reckoned a matter for +congratulation that the rigid airship did not decide the fate of the +War. The following particulars of construction of the R.33 and R.34 +types are as given by Major Whale in his survey of British Airships:-- + +'In all its main features the hull structure of R.33 and R.34 follows +the design of the wrecked German Zeppelin airship L.33. 'The hull +follows more nearly a true stream-line shape than in the previous ships +constructed of duralumin, in which a greater proportion of the greater +length was parallel-sided. The Germans adopted this new shape from +the Schutte-Lanz design and have not departed from this practice. This +consists of a short, parallel body with a long, rounded bow and a long +tapering stem culminating in a point. The overall length of the ship is +643 feet with a diameter of 79 feet and an extreme height of 92 feet. + +'The type of girders in this class has been much altered from those +in previous ships. The hull is fitted with an internal triangular keel +throughout practically the entire length. This forms the main corridor +of the ship, and is fitted with a footway down the centre for its entire +length. It contains water ballast and petrol tanks, bomb storage and +crew accommodation, and the various control wires, petrol pipes, and +electric leads are carried along the lower part. + +'Throughout this internal corridor runs a bridge girder, from which +the petrol and water ballast tanks are supported. These tanks are so +arranged that they can be dropped clear of the ship. Amidships is the +cabin space with sufficient room for a crew of twenty-five. Hammocks can +be swung from the bridge girder before mentioned. + +'In accordance with the latest Zeppelin practice, monoplane rudders and +elevators are fitted to the horizontal and vertical fins. + +'The ship is supported in the air by nineteen gas bags, which give a +total capacity of approximately two million cubic feet of gas. The gross +lift works out at approximately 59 1/2 tons, of which the total fixed +weight is 33 tons, giving a disposable lift of 26 1/2 tons. + +'The arrangement of cars is as follows: At the forward end the control +car is slung, which contains all navigating instruments and the various +controls. Adjoining this is the wireless cabin, which is also fitted +for wireless telephony. Immediately aft of this is the forward power car +containing one engine, which gives the appearance that the whole is one +large car. + +'Amidships are two wing cars, each containing a single engine. These +are small and just accommodate the engines with sufficient room for +mechanics to attend to them. Further aft is another larger car which +contains an auxiliary control position and two engines. + +'It will thus be seen that five engines are installed in the ship; +these are all of the same type and horsepower, namely, 250 horse-power +Sunbeam. R.33 was constructed by Messrs Armstrong, Whitworth, Ltd.; +while her sister ship R.34 was built by Messrs Beardmore on the Clyde.' + +Of the two vessels, R.34 appeared rather more airworthy than her sister +ship; the lift of the ship justified the carrying of a greater quantity +of fuel than had been provided for, and, as she was considered suitable +for making a Transatlantic crossing, extra petrol tanks were fitted in +the hull and a new type of outer cover was fitted with a view to her +making the Atlantic crossing. She made a 21-hour cruise over the North +of England and the South of Scotland at the end of May, 1919, and +subsequently went for a longer cruise over Denmark, the Baltic, and the +north coast of Germany, remaining in the air for 56 hours in spite +of very bad weather conditions. Finally, July 2nd was selected as the +starting date for the cross Atlantic flight; the vessel was commanded +by Major G. H. Scott, A.F.C., with Captain G. S. Greenland as first +officer, Second-Lieut. H. F. Luck as second officer, and Lieut. J. D. +Shotter as engineer officer. There were also on board Brig.-Gen. E. +P. Maitland, representing the Air Ministry, Major J. E. M. Pritchard, +representing the Admiralty, and Lieut.-Col. W. H. Hemsley of the Army +Aviation Department. In addition to eight tons of petrol, R.34 carried a +total number of 30 persons from East Fortune to Long Island, N.Y. + +There being no shed in America capable of accommodating the airship, +she had to be moored in the open for refilling with fuel and gas, and to +make the return journey almost immediately. + +Brig.-Gen. Maitland's account of the flight, in itself a record as +interesting as valuable, divides the outward journey into two main +stages, the first from East Fortune to Trinity Bay, Newfoundland, a +distance of 2,050 sea miles, and the second and more difficult stage +to Mineola Field, Long Island, 1,080 sea miles. An easy journey +was experienced until Newfoundland was reached, but then storms and +electrical disturbances rendered it necessary to alter the course, in +consequence of which petrol began to run short. Head winds rendered the +shortage still more acute, and on Saturday, July 5th, a wireless signal +was sent out asking for destroyers to stand by to tow. However, after an +anxious night, R.33 landed safely at Mineola Field at 9.55 a.m. on July +6th, having accomplished the journey in 108 hours 12 minutes. + +She remained at Mineola until midnight of July 9th, when, although +it had been intended that a start should be made by daylight for the +benefit of New York spectators, an approaching storm caused preparations +to be advanced for immediate departure. She set out at 5.57 a.m. +by British summer time, and flew over New York in the full glare +of hundreds of searchlights before heading out over the Atlantic. A +following wind assisted the return voyage, and on July 13th, at 7.57 +a.m., R.34 anchored at Pulham, Norfolk, having made the return journey +in 75 hours 3 minutes, and proved the suitability of the dirigible +for Transatlantic commercial work. R.80, launched on July 19th, 1920, +afforded further proof, if this were needed. + +It is to be noted that nearly all the disasters to airships have been +caused by launching and landing--the type is safe enough in the air, +under its own power, but its bulk renders it unwieldy for ground +handling. The German system of handling Zeppelins in and out of their +sheds is, so far, the best devised: this consists of heavy trucks +running on rails through the sheds and out at either end; on descending, +the trucks are run out, and the airship is securely attached to them +outside the shed; the trucks are then run back into the shed, taking the +airship with them, and preventing any possibility of the wind driving +the envelope against the side of the shed before it is safely housed; +the reverse process is adopted in launching, which is thus rendered as +simple as it is safe. + + + + +VI. THE AIRSHIP COMMERCIALLY + +Prior to the war period, between the years 1910 and 1914, a German +undertaking called the Deutsche Luftfahrt Actien Gesellschaft conducted +a commercial Zeppelin service in which four airships known as the +Sachsan, Hansa, Victoria Louise, and Schwaben were used. During the four +years of its work, the company carried over 17,000 passengers, and over +100,000 miles were flown without incurring one fatality and with only +minor and unavoidable accidents to the vessels composing the service. +Although a number of English notabilities made voyages in these +airships, the success of this only experiment in commercial aerostation +seems to have been forgotten since the war. There was beyond doubt a +military aim in this apparently peaceful use of Zeppelin airships; it is +past question now that all Germany's mechanical development in respect +of land sea, and air transport in the years immediately preceding the +war, was accomplished with the ulterior aim of military conquest, but, +at the same time, the running of this service afforded proof of the +possibility of establishing a dirigible service for peaceful ends, and +afforded proof too, of the value of the dirigible as a vessel of purely +commercial utility. + +In considering the possibility of a commercial dirigible service, it +is necessary always to bear in mind the disadvantages of first cost and +upkeep as compared with the aeroplane. The building of a modern rigid +is an exceedingly costly undertaking, and the provision of an efficient +supply of hydrogen gas to keep its compartments filled is a very large +item in upkeep of which the heavier-than-air machine goes free. Yet +the future of commercial aeronautics so far would seem to lie with the +dirigible where very long voyages are in question. No matter how the +aeroplane may be improved, the possibility of engine failure always +remains as a danger for work over water. In seaplane or flying boat +form, the danger is still present in a rough sea, though in the American +Transatlantic flight, N.C.3, taxi-ing 300 miles to the Azores after +having fallen to the water, proved that this danger is not so acute as +is generally assumed. Yet the multiple-engined rigid, as R.34 showed on +her return voyage, may have part of her power plant put out of action +altogether and still complete her voyage very successfully, which, in +the case of mail carrying and services run strictly to time, gives her +an enormous advantage over the heavier-than-air machine. + +'For commercial purposes,' General Sykes has remarked, 'the airship is +eminently adapted for long distance journeys involving non-stop flights. +It has this inherent advantage over the aeroplane, that while there +appears to be a limit to the range of the aeroplane as at present +constructed, there is practically no limit whatever to that of the +airship, as this can be overcome by merely increasing the size. It thus +appears that for such journeys as crossing the Atlantic, or crossing +the Pacific from the west coast of America to Australia or Japan, the +airship will be peculiarly suitable. It having been conceded that the +scope of the airship is long distance travel, the only type which need +be considered for this purpose is the rigid. The rigid airship is still +in an embryonic state, but sufficient has already been accomplished +in this country, and more particularly in Germany, to show that with +increased capacity there is no reason why, within a few years' time, +airships should not be built capable of completing the circuit of the +globe and of conveying sufficient passengers and merchandise to render +such an undertaking a paying proposition.' + +The British R.38 class, embodying the latest improvements in airship +design outside Germany, gives a gross lift per airship of 85 tons and a +net lift of about 45 tons. The capacity of the gas bags is about two +and three-quarter million cubic feet, and, travelling at the rate of +45 miles per hour, the cruising range of the vessel is estimated at 8.8 +days. Six engines, each of 350 horse-power, admit of an extreme speed of +70 miles per hour if necessary. + +The last word in German design is exemplified in the rigids L.70 and +L.71, together with the commercial airship 'Bodensee.' Previous to the +construction of these, the L.65 type is noteworthy as being the first +Zeppelin in which direct drive of the propeller was introduced, together +with an improved and lighter type of car. L.70 built in 1918 and +destroyed by the British naval forces, had a speed of about 75 miles per +hour; L.71 had a maximum speed of 72 miles per hour, a gas bag capacity +of 2,420,000 cubic feet, and a length of 743 feet, while the total lift +was 73 tons. Progress in design is best shown by the progress in useful +load; in the L.70 and L.71 class, this has been increased to 58.3 per +cent, while in the Bodensee it was ever higher. + +As was shown in R.34's American flight, the main problem in connection +with the commercial use of dirigibles is that of mooring in the open. +The nearest to a solution of this problem, so far, consists in the mast +carrying a swivelling cap; this has been tried in the British service +with a non-rigid airship, which was attached to a mast in open country +in a gale of 52 miles an hour without the slightest damage to the +airship. In its commercial form, the mast would probably take the +form of a tower, at the top of which the cap would revolve so that +the airship should always face the wind, the tower being used for +embarkation and disembarkation of passengers and the provision of fuel +and gas. Such a system would render sheds unnecessary except in case of +repairs, and would enormously decrease the establishment charges of any +commercial airship. + +All this, however, is hypothetical. Remains the airship of to-day, +developed far beyond the promise of five years ago, capable, as has +been proved by its achievements both in Britain and in Germany, of +undertaking practically any given voyage with success. + + + + +VII. KITE BALLOONS + +As far back as the period of the Napoleonic wars, the balloon was +given a place in warfare, but up to the Franco-Prussian Prussian War +of 1870-71 its use was intermittent. The Federal forces made use of +balloons to a small extent in the American Civil War; they came to great +prominence in the siege of Paris, carrying out upwards of three million +letters and sundry carrier pigeons which took back messages into the +besieged city. Meanwhile, as captive balloons, the German and other +armies used them for observation and the direction of artillery fire. In +this work the ordinary spherical balloon was at a grave disadvantage; if +a gust of wind struck it, the balloon was blown downward and down +wind, generally twirling in the air and upsetting any calculations and +estimates that might be made by the observers, while in a wind of 25 +miles an hour it could not rise at all. The rotatory movement caused by +wind was stopped by an experimenter in the Russo-Japanese war, who fixed +to the captive observation balloons a fin which acted as a rudder. This +did not stop the balloon from being blown downward and away from its +mooring station, but this tendency was overcome by a modification +designed in Germany by the Parseval-Siegsfield Company, which originated +what has since become familiar as the 'Sausage' or kite balloon. This +is so arranged that the forward end is tilted up into the wind, and the +underside of the gas bag, acting as a plane, gives the balloon a lifting +tendency in a wind, thus counteracting the tendency of the wind to blow +it downward and away from its mooring station. Smaller bags are fitted +at the lower and rear end of the balloon with openings that face into +the wind; these are thus kept inflated, and they serve the purpose of a +rudder, keeping the kite balloon steady in the air. + +Various types of kite balloon have been introduced; the original German +Parseval-Siegsfield had a single air bag at the stern end, which was +modified to two, three, or more lobes in later varieties, while an +American experimental design attempted to do away with the attached +lobes altogether by stringing out a series of small air bags, kite +fashion, in rear of the main envelope. At the beginning of the War, +Germany alone had kite balloons, for the authorities of the Allied +armies con-sidered that the bulk of such a vessel rendered it too +conspicuous a mark to permit of its being serviceable. The Belgian +arm alone possessed two which, on being put into service, were found +extremely useful. The French followed by constructing kite balloons at +Chalais Meudon, and then, after some months of hostilities and with the +example of the Royal Naval Air Service to encourage them, the British +military authorities finally took up the construction and use of kite +balloons for artillery-spotting and general observation purposes. +Although many were brought down by gun-fire, their uses far outweighed +their disadvantages, and toward the end of the War, hardly a mile of +front was without its 'Sausage.' + +For naval work, kite balloons were carried in a specially constructed +hold in the forepart of certain vessels; when required for use, the +covering of the hold was removed, the kite balloon inflated and released +to the required height by means of winches as in the case of the +land work. The perfecting of the 'Coastal' and N.S. types of airship, +together with the extension of wireless telephony between airship and +cruiser or other warship, in all probability will render the use of the +kite balloon unnecessary in connection with naval scouting. But, during +the War, neither wireless telephony nor naval airships had developed +sufficiently to render the Navy independent of any means that might come +to hand, and the fitting of kite balloons in this fashion filled a need +of the times. + +A necessary accessory of the kite balloon is the parachute, which has +a long history. Da Vinci and Veranzio appear to have been the first +exponents, the first in the theory and the latter in the practice of +parachuting. Montgolfier experimented at Annonay before he constructed +his first hot air-balloon, and in 1783 a certain Lenormand dropped from +a tree in a parachute. Blanchard the balloonist made a spectacle +of parachuting, and made it a financial success; Cocking, in 1836, +attempted to use an inverted form of parachute; taken up to a height +of 3,000 feet, he was cut adrift, when the framework of the parachute +collapsed and Cocking was killed. + +The rate of fall is slow in parachuting to the ground. Frau Poitevin, +making a descent from a height of 6,000 feet, took 45 minutes to reach +the ground, and, when she alighted, her husband, who had taken her up, +had nearly got his balloon packed up. Robertson, another parachutist is +said to have descended from a height of 10,000 feet in 35 minutes, or +at a rate of nearly 5 feet per second. During the War Brigadier-General +Maitland made a parachute descent from a height of 10,000 feet, the time +taken being about 20 minutes. + +The parachute was developed considerably during the War period, the main +requirement, that of certainty in opening, being considerably developed. +Considered a necessary accessory for kite balloons, the parachute was +also partially adopted for use with aeroplanes in the later War period, +when it was contended that if a machine were shot down in flames, its +occupants would be given a far better chance of escape if they had +parachutes. Various trials were made to demonstrate the extreme +efficiency of the parachute in modern form, one of them being a descent +from the upper ways of the Tower Bridge to the waters of the Thames, in +which short distance the 'Guardian Angel' type of parachute opened and +cushioned the descent for its user. + +For dirigibles, balloons, and kite balloons the parachute is an +essential. It would seem to be equally essential in the case of +heavier-than-air machines, but this point is still debated. Certainly +it affords the occupant of a falling aeroplane a chance, no matter how +slender, of reaching the ground in safety, and, for that reason, it +would seem to have a place in aviation as well as in aerostation. + + + + +PART IV. ENGINE DEVELOPMENT + + + + +I. THE VERTICAL TYPE + +The balloon was but a year old when the brothers Robert, in 1784 +attempted propulsion of an aerial vehicle by hand-power, and succeeded, +to a certain extent, since they were able to make progress when there +was only a slight wind to counteract their work. But, as may be easily +understood, the manual power provided gave but a very slow speed, and in +any wind it all the would-be airship became an uncontrolled balloon. + +Henson and Stringfellow, with their light steam engines, were first to +attempt conquest of the problem of mechanical propulsion in the +air; their work in this direction is so fully linked up with their +constructed models that it has been outlined in the section dealing +with the development of the aeroplane. But, very shortly after these +two began, there came into the field a Monsieur Henri Giffard, who first +achieved success in the propulsion by mechanical means of dirigible +balloons, for his was the first airship to fly against the wind. +He employed a small steam-engine developing about 3 horse-power and +weighing 350 lbs. with boiler, fitting the whole in a car suspended from +the gas-bag of his dirigible. The propeller which this engine worked +was 11 feet in diameter, and the inventor, who made several flights, +obtained a speed of 6 miles an hour against a slight wind. The power +was not sufficient to render the invention practicable, as the dirigible +could only be used in calm weather, but Giffard was sufficiently +encouraged by his results to get out plans for immense dirigibles, +which through lack of funds he was unable to construct. When, later, his +invention of the steam-injector gave him the means he desired, he became +blind, and in 1882 died, having built but the one famous dirigible. + +This appears to have been the only instance of a steam engine being +fitted to a dirigible; the inherent disadvantage of this form of motive +power is that a boiler to generate the steam must be carried, and this, +together with the weight of water and fuel, renders the steam engine +uneconomical in relation to the lift either of plane or gas-bag. Again, +even if the weight could be brought down to a reasonable amount, the +attention required by steam plant renders it undesirable as a motive +power for aircraft when compared with the internal combustion engine. + +Maxim, in Artificial and Natural Flight, details the engine which he +constructed for use with his giant experimental flying machine, and his +description is worthy of reproduction since it is that of the only steam +engine besides Giffard's, and apart from those used for the propulsion +of models, designed for driving an aeroplane. 'In 1889,' Maxim says, +'I had my attention drawn to some very thin, strong, and comparatively +cheap tubes which were being made in France, and it was only after I had +seen these tubes that I seriously considered the question of making a +flying machine. I obtained a large quantity of them and found that they +were very light, that they would stand enormously high pressures, and +generate a very large quantity of steam. Upon going into a mathematical +calculation of the whole subject, I found that it would be possible to +make a machine on the aeroplane system, driven by a steam engine, which +would be sufficiently strong to lift itself into the air. I first made +drawings of a steam engine, and a pair of these engines was afterwards +made. These engines are constructed, for the most part, of a very high +grade of cast steel, the cylinders being only 3/32 of an inch thick, +the crank shafts hollow, and every part as strong and light as possible. +They are compound, each having a high-pressure piston with an area of +20 square inches, a low-pressure piston of 50.26 square inches, and a +common stroke of 1 foot. When first finished they were found to weigh +300 lbs. each; but after putting on the oil cups, felting, painting, and +making some slight alterations, the weight was brought up to 320 lbs. +each, or a total of 640 lbs. for the two engines, which have since +developed 362 horsepower with a steam pressure of 320 lbs. per square +inch.' + +The result is remarkable, being less than 2 lbs. weight per horse-power, +especially when one considers the state of development to which the +steam engine had attained at the time these experiments were made. The +fining down of the internal combustion engine, which has done so much to +solve the problems of power in relation to weight for use with aircraft, +had not then been begun, and Maxim had nothing to guide him, so far +as work on the part of his predecessors was concerned, save the +experimental engines of Stringfellow, which, being constructed on so +small a scale in comparison with his own, afforded little guidance. +Concerning the factor of power, he says: 'When first designing this +engine, I did not know how much power I might require from it. I thought +that in some cases it might be necessary to allow the high-pressure +steam to enter the low-pressure cylinder direct, but as this would +involve a considerable loss, I constructed a species of injector. This +injector may be so adjusted that when the steam in the boiler rises +above a certain predetermined point, say 300 lbs., to the square inch, +it opens a valve and escapes past the high-pressure cylinder instead of +blowing off at the safety valve. In escaping through this valve, a fall +of about 200 lbs. pressure per square inch is made to do work on the +surrounding steam and drive it forward in the pipe, producing a pressure +on the low-pressure piston considerably higher than the back-pressure on +the high-pressure piston. In this way a portion of the work which would +otherwise be lost is utilised, and it is possible, with an unlimited +supply of steam, to cause the engines to develop an enormous amount of +power.' + +With regard to boilers, Maxim writes, + +'The first boiler which I made was constructed something on the +Herreshof principle, but instead of having one simple pipe in one very +long coil, I used a series of very small and light pipes, connected in +such a manner that there was a rapid circulation through the whole--the +tubes increasing in size and number as the steam was generated. I +intended that there should be a pressure of about 100 lbs. more on the +feed water end of the series than on the steam end, and I believed that +this difference in pressure would be sufficient to ensure direct and +positive circulation through every tube in the series. The first boiler +was exceedingly light, but the workmanship, as far as putting the tubes +together was concerned, was very bad, and it was found impossible to so +adjust the supply of water as to make dry steam without overheating and +destroying the tubes. + +'Before making another boiler I obtained a quantity of copper tubes, +about 8 feet long, 3/8 inch external diameter, and 1/50 of an inch +thick. I subjected about 100 of these tubes to an internal pressure of +1 ton per square inch of cold kerosene oil, and as none of them leaked +I did not test any more, but commenced my experiments by placing some +of them in a white-hot petroleum fire. I found that I could evaporate +as much as 26 1/2 lbs. of water per square foot of heating surface per +hour, and that with a forced circulation, although the quantity of water +passing was very small but positive, there was no danger of overheating. +I conducted many experiments with a pressure of over 400 lbs. per square +inch, but none of the tubes failed. I then mounted a single tube in a +white-hot furnace, also with a water circulation, and found that it only +burst under steam at a pressure of 1,650 lbs. per square inch. A large +boiler, having about 800 square feet of heating surface, including the +feed-water heater, was then constructed. This boiler is about 4 1/2 feet +wide at the bottom, 8 feet long and 6 feet high. It weighs, with the +casing, the dome, and the smoke stack and connections, a little less +than 1,000 lbs. The water first passes through a system of small +tubes--1/4 inch in diameter and 1/60 inch thick--which were placed at +the top of the boiler and immediately over the large tubes.... This +feed-water heater is found to be very effective. It utilises the heat +of the products of combustion after they have passed through the boiler +proper and greatly reduces their temperature, while the feed-water +enters the boiler at a temperature of about 250 F. A forced circulation +is maintained in the boiler, the feed-water entering through a spring +valve, the spring valve being adjusted in such a manner that the +pressure on the water is always 30 lbs. per square inch in excess of +the boiler pressure. This fall of 30 lbs. in pressure acts upon the +surrounding hot water which has already passed through the tubes, and +drives it down through a vertical outside tube, thus ensuring a positive +and rapid circulation through all the tubes. This apparatus is found to +act extremely well.' + +Thus Maxim, who with this engine as power for his large aeroplane +achieved free flight once, as a matter of experiment, though for what +distance or time the machine was actually off the ground is matter for +debate, since it only got free by tearing up the rails which were to +have held it down in the experiment. Here, however, was a steam engine +which was practicable for use in the air, obviously, and only the rapid +success of the internal combustion engine prevented the steam-producing +type from being developed toward perfection. + +The first designers of internal combustion engines, knowing nothing +of the petrol of these days, constructed their examples with a view to +using gas as fuel. As far back as 1872 Herr Paul Haenlein obtained a +speed of about 10 miles an hour with a balloon propelled by an internal +combustion engine, of which the fuel was gas obtained from the balloon +itself. The engine in this case was of the Lenoir type, developing +some 6 horse-power, and, obviously, Haenlein's flights were purely +experimental and of short duration, since he used the gas that sustained +him and decreased the lifting power of his balloon with every stroke of +the piston of his engine. No further progress appears to have been made +with the gas-consuming type of internal combustion engine for work +with aircraft; this type has the disadvantage of requiring either a +gas-producer or a large storage capacity for the gas, either of which +makes the total weight of the power plant much greater than that of +a petrol engine. The latter type also requires less attention when +working, and the fuel is more convenient both for carrying and in the +matter of carburation. + +The first airship propelled by the present-day type of internal +combustion engine was constructed by Baumgarten and Wolfert in 1879 +at Leipzig, the engine being made by Daimler with a view to working on +benzine--petrol as a fuel had not then come to its own. The construction +of this engine is interesting since it was one of the first of Daimler's +make, and it was the development brought about by the experimental +series of which this engine was one that led to the success of the +motor-car in very few years, incidentally leading to that fining down of +the internal combustion engine which has facilitated the development +of the aeroplane with such remarkable rapidity. Owing to the faulty +construction of the airship no useful information was obtained from +Daimler's pioneer installation, as the vessel got out of control +immediately after it was first launched for flight, and was wrecked. +Subsequent attempts at mechanically-propelled flight by Wolfert ended, +in 1897, in the balloon being set on fire by an explosion of benzine +vapour, resulting in the death of both the aeronauts. + +Daimler, from 1882 onward, devoted his attention to the perfecting of +the small, high-speed petrol engine for motor-car work, and owing to +his efforts, together with those of other pioneer engine-builders, the +motorcar was made a success. In a few years the weight of this type of +engine was reduced from near on a hundred pounds per horse-power to less +than a tenth of that weight, but considerable further improvement had to +be made before an engine suitable for use with aircraft was evolved. + +The increase in power of the engines fitted to airships has made +steady progress from the outset; Haenlein's engine developed about 6 +horse-power; the Santos-Dumont airship of 1898 was propelled by a motor +of 4 horse-power; in 1902 the Lebaudy airship was fitted with an engine +of 40 horse-power, while, in 1910, the Lebaudy brothers fitted an +engine of nearly 300 horsepower to the airship they were then +constructing--1,400 horse-power was common in the airships of the War +period, and the later British rigids developed yet more. + +Before passing on to consideration of the petrol-driven type of engine, +it is necessary to accord brief mention to the dirigible constructed in +1884 by Gaston and Albert Tissandier, who at Grenelle, France, achieved +a directed flight in a wind of 8 miles an hour, obtaining their power +for the propeller from 1 1/3 horse-power Siemens electric motor, which +weighed 121 lbs. and took its current from a bichromate battery weighing +496 lbs. A two-bladed propeller, 9 feet in diameter, was used, and +the horse-power output was estimated to have run up to 1 1/2 as the +dirigible successfully described a semicircle in a wind of 8 miles an +hour, subsequently making headway transversely to a wind of 7 miles +an hour. The dirigible with which this motor was used was of the +conventional pointed-end type, with a length of 92 feet, diameter of 30 +feet, and capacity of 37,440 cubic feet of gas. Commandant Renard, of +the French army balloon corps, followed up Tissandier's attempt in +the next year--1885--making a trip from Chalais-Meudon to Paris and +returning to the point of departure quite successfully. In this case the +motive power was derived from an electric plant of the type used by +the Tissandiers, weighing altogether 1,174 lbs., and developing +9 horsepower. A speed of 14 miles an hour was attained with this +dirigible, which had a length of 165 feet, diameter of 27 feet, and +capacity of 65,836 cubic feet of gas. + +Reverting to the petrol-fed type again, it is to be noted that +Santos-Dumont was practically the first to develop the use of the +ordinary automobile engine for air work--his work is of such importance +that it has been considered best to treat of it as one whole, and +details of the power plants are included in the account of his +experiments. Coming to the Lebaudy brothers and their work, their engine +of 1902 was a 40 horse-power Daimler, four-cylindered; it was virtually +a large edition of the Daimler car engine, the arrangement of the +various details being on the lines usually adopted for the standard +Daimler type of that period. The cylinders were fully water-jacketed, +and no special attempt toward securing lightness for air work appears to +have been made. + +The fining down of detail that brought weight to such limits as would +fit the engine for work with heavier-than-air craft appears to have +waited for the brothers Wright. Toward the end of 1903 they fitted +to their first practicable flying machine the engine which made the +historic first aeroplane flight; this engine developed 30 horse-power, +and weighed only about 7 lbs. per horse-power developed, its design and +workmanship being far ahead of any previous design in this respect, with +the exception of the remarkable engine, designed by Manly, installed in +Langley's ill-fated aeroplane--or 'aerodrome,' as he preferred to call +it--tried in 1903. + +The light weight of the Wright brothers' engine did not necessitate a +high number of revolutions per minute to get the requisite power; the +speed was only 1,300 revolutions per minute, which, with a piston +stroke of 3.94 inches, was quite moderate. Four cylinders were used, +the cylinder diameter being 4.42 inches; the engine was of the +vertical type, arranged to drive two propellers at a rate of about 350 +revolutions per minute, gearing being accomplished by means of chain +drive from crank-shaft end to propeller spindle. + +The methods adopted by the Wrights for obtaining a light-weight engine +were of considerable interest, in view of the fact that the honour +of first achieving flight by means of the driven plane belongs to +them--unless Ader actually flew as he claimed. The cylinders of this +first Wright engine were separate castings of steel, and only the +barrels were jacketed, this being done by fixing loose, thin aluminium +covers round the outside of each cylinder. The combustion head and valve +pockets were cast together with the cylinder barrel, and were not water +cooled. The inlet valves were of the automatic type, arranged on the +tops of the cylinders, while the exhaust valves were also overhead, +operated by rockers and push-rods. The pistons and piston rings were +of the ordinary type, made of cast-iron, and the connecting rods were +circular in form, with a hole drilled down the middle of each to reduce +the weight. + +Necessity for increasing power and ever lighter weight in relation to +the power produced has led to the evolution of a number of different +designs of internal combustion engines. It was quickly realised that +increasing the number of cylinders on an engine was a better way of +getting more power than that of increasing the cylinder diameter, as the +greater number of cylinders gives better torque-even turning effect--as +well as keeping down the weight--this latter because the bigger +cylinders must be more stoutly constructed than the small sizes; this +fact has led to the construction of engines having as many as eighteen +cylinders, arranged in three parallel rows in order to keep the length +of crankshaft within reasonable limits. The aero engine of to-day may, +roughly, be divided into four classes: these are the V type, in which +two rows of cylinders are set parallel at a certain angle to each other; +the radial type, which consists of cylinders arranged radially and +remaining stationary while the crankshaft revolves; the rotary, where +the cylinders are disposed round a common centre and revolve round +a stationary shaft, and the vertical type, of four or six +cylinders--seldom more than this--arranged in one row. A modification of +the V type is the eighteen-cylindered engine--the Sunbeam is one of the +best examples--in which three rows of cylinders are set parallel to each +other, working on a common crankshaft. The development these four types +started with that of the vertical--the simplest of all; the V, radial, +and rotary types came after the vertical, in the order given. + +The evolution of the motor-car led to the adoption of the vertical +type of internal combustion engine in preference to any other, and +it followed naturally that vertical engines should be first used for +aeroplane propulsion, as by taking an engine that had been developed to +some extent, and adapting it to its new work, the problem of mechanical +flight was rendered easier than if a totally new type had had to be +evolved. It was quickly realised--by the Wrights, in fact-that the +minimum of weight per horse-power was the prime requirement for the +successful development of heavier-than-air machines, and at the same +time it was equally apparent that the utmost reliability had to be +obtained from the engine, while a third requisite was economy, in order +to reduce the weight of petrol necessary for flight. + +Daimler, working steadily toward the improvement of the internal +combustion engine, had made considerable progress by the end of +last century. His two-cylinder engine of 1897 was approaching to +the present-day type, except as regards the method of ignition; the +cylinders had 3.55 inch diameter, with a 4.75 inch piston stroke, +and the engine was rated at 4.5 brake horse-power, though it probably +developed more than this in actual running at its rated speed of 800 +revolutions per minute. Power was limited by the inlet and exhaust +passages, which, compared with present-day practice, were very small. +The heavy castings of which the engine was made up are accounted for by +the necessity for considering foundry practice of the time, for in 1897 +castings were far below the present-day standard. The crank-case of +this two-cylinder vertical Daimler engine was the only part made of +aluminium, and even with this no attempt was made to attain lightness, +for a circular flange was cast at the bottom to form a stand for the +engine during machining and erection. The general design can be followed +from the sectional views, and these will show, too, that ignition was by +means of a hot tube on the cylinder head, which had to be heated with a +blow-lamp before starting the engine. With all its well known and hated +troubles, at that time tube ignition had an advantage over the magneto, +and the coil and accumulator system, in reliability; sparking plugs, +too, were not so reliable then as they are now. Daimler fitted a very +simple type of carburettor to this engine, consisting only of a float +with a single jet placed in the air passage. It may be said that this +twin-cylindered vertical was the first of the series from which has been +evolved the Mercedes-Daimler car and airship engines, built in sizes up +to and even beyond 240 horse-power. + +In 1901 the development of the petrol engine was still so slight that it +did not admit of the construction, by any European maker, of an engine +weighing less than 12 lbs. per horse-power. Manly, working at the +instance of Professor Langley, produced a five-cylindered radial type +engine, in which both the design and workmanship showed a remarkable +advance in construction. At 950 revolutions per minute it developed 52.4 +horse-power, weighing only 2.4 pounds per horse-power; it was a very +remarkable achievement in engine design, considering the power developed +in relation to the total weight, and it was, too, an interruption in +the development of the vertical type which showed that there were other +equally great possibilities in design. + +In England, the first vertical aero-engine of note was that designed +by Green, the cylinder dimensions being 4.15 inch diameter by 4.75 +stroke--a fairly complete idea of this engine can be obtained from the +accompanying diagrams. At a speed of 1,160 revolutions per minute +it developed 35 brake horse-power, and by accelerating up to 1,220 +revolutions per minute a maximum of 40 brake horse-power could be +obtained--the first-mentioned was the rated working speed of the engine +for continuous runs. A flywheel, weighing 23.5 lbs., was fitted to the +engine, and this, together with the ignition system, brought the weight +up to 188 lbs., giving 5.4 lbs. per horse-power. In comparison with the +engine fitted to the Wrights' aeroplane a greater power was obtained +from approximately the same cylinder volume, and an appreciable saving +in weight had also been effected. The illustration shows the arrangement +of the vertical valves at the top of the cylinder and the overhead cam +shaft, while the position of the carburettor and inlet pipes can be +also seen. The water jackets were formed by thin copper casings, each +cylinder being separate and having its independent jacket rigidly +fastened to the cylinder at the top only, thus allowing for free +expansion of the casing; the joint at the bottom end was formed by +sliding the jacket over a rubber ring. Each cylinder was bolted to the +crank-case and set out of line with the crankshaft, so that the crank +has passed over the upper dead centre by the time that the piston is at +the top of its stroke when receiving the full force of fuel explosion. +The advantage of this desaxe setting is that the pressure in the +cylinder acts on the crank-pin with a more effective leverage during +that part of the stroke when that pressure is highest, and in addition +the side pressure of the piston on the cylinder wall, due to the thrust +of the connecting rod, is reduced. Possibly the charging of the cylinder +is also more complete by this arrangement, owing to the slower movement +of the piston at the bottom of its stroke allowing time for an increased +charge of mixture to enter the cylinder. + +A 60 horse-power engine was also made, having four vertical cylinders, +each with a diameter of 5.5 inches and stroke of 5.75 inches, developing +its rated power at 1,100 revolutions per minute. By accelerating up to +1,200 revolutions per minute 70 brake horsepower could be obtained, and +a maximum of 80 brake horse-power was actually attained with the type. +The flywheel, fitted as with the original 35 horse-power engine, weighed +37 lbs.; with this and with the ignition system the total weight of +the engine was only 250 lbs., or 4.2 lbs. per horse-power at the normal +rating. In this design, however, low weight in relation to power was +not the ruling factor, for Green gave more attention to reliability and +economy of fuel consumption, which latter was approximately 0.6 pint of +petrol per brake horse-power per hour. Both the oil for lubricating +the bearings and the water for cooling the cylinders were circulated by +pumps, and all parts of the valve gear, etc., were completely enclosed +for protection from dust. + +A later development of the Green engine was a six-cylindered vertical, +cylinder dimensions being 5.5 inch diameter by 6 inch stroke, developing +120 brake horsepower when running at 1,250 revolutions per minute. The +total weight of the engine with ignition system 398 was 440 lbs., or +3.66 lbs. per horse-power. One of these engines was used on the machine +which, in 1909, won the prize of L1,000 for the first circular mile +flight, and it may be noted, too, that S. F. Cody, making the circuit +of England in 1911, used a four-cylinder Green engine. Again, it was a +Green engine that in 1914 won the L5,000 prize offered for the best aero +engine in the Naval and Military aeroplane engine competition. + +Manufacture of the Green engines, in the period of the War, had +standardised to the production of three types. Two of these were +six-cylinder models, giving respectively 100 and 150 brake horse-power, +and the third was a twelve-cylindered model rated at 275 brake +horse-power. + +In 1910 J. S. Critchley compiled a list showing the types of engine then +being manufactured; twenty-two out of a total of seventy-six were of the +four-cylindered vertical type, and in addition to these there were two +six-cylindered verticals. The sizes of the four-cylinder types ranged +from 26 up to 118 brake horse-power; fourteen of them developed less +than 50 horse-power, and only two developed over 100 horse-power. + +It became apparent, even in the early stages of heavier-than-air flying, +that four-cylinder engines did not produce the even torque that was +required for the rotation of the power shaft, even though a flywheel +was fitted to the engine. With this type of engine the breakage of +air-screws was of frequent occurrence, and an engine having a more +regular rotation was sought, both for this and to avoid the excessive +vibration often experienced with the four-cylinder type. Another, point +that forced itself on engine builders was that the increased power which +was becoming necessary for the propulsion of aircraft made an increase +in the number of cylinders essential, in order to obtain a light engine. +An instance of the weight reduction obtainable in using six cylinders +instead of four is shown in Critchley's list, for one of the +four-cylinder engines developed 118.5 brake horse-power and weighed +1,100 lbs., whereas a six-cylinder engine by the same manufacturer +developed 117.5 brake horse-power with a weight of 880 lbs., the +respective cylinder dimensions being 7.48 diameter by 9.06 stroke +for the four-cylinder engine, and 6.1 diameter by 7.28 stroke for the +six-cylinder type. + +A list of aeroplane engines, prepared in 1912 by Graham Clark, showed +that, out of the total number of 112 engines then being manufactured, +forty-two were of the vertical type, and of this number twenty-four had +four-cylinders while sixteen were six-cylindered. The German aeroplane +engine trials were held a year later, and sixty-six engines entered the +competition, fourteen of these being made with air-cooled cylinders. +All of the ten engines that were chosen for the final trials were of the +water-cooled type, and the first place was won by a Benz four-cylinder +vertical engine which developed 102 brake horse-power at 1,288 +revolutions per minute. The cylinder dimensions of this engine were 5.1 +inch diameter by 7.1 inch stroke, and the weight of the engine worked +out at 3.4 lbs. per brake horse-power. During the trials the full-load +petrol consumption was 0.53 pint per horse-power per hour, and the +amount of lubricating oil used was 0.0385 pint per brake horse-power per +hour. In general construction this Benz engine was somewhat similar to +the Green engine already described; the overhead valves, fitted in the +tops of the cylinders, were similarly arranged, as was the cam-shaft; +two springs were fitted to each of the valves to guard against the +possibility of the engine being put out of action by breakage of one +of the springs, and ignition was obtained by two high-tension magnetos +giving simultaneous sparks in each cylinder by means of two sparking +plugs--this dual ignition reduced the possibility of ignition troubles. +The cylinder jackets were made of welded sheet steel so fitted around +the cylinder that the head was also water-cooled, and the jackets were +corrugated in the middle to admit of independent expansion. Even the +lubrication system was duplicated, two sets of pumps being used, one to +circulate the main supply of lubricating oil, and the other to give a +continuous supply of fresh oil to the bearings, so that if the +supply from one pump failed the other could still maintain effective +lubrication. + +Development of the early Daimler type brought about the four-cylinder +vertical Mercedes-Daimler engine of 85 horse-power, with cylinders +of 5.5 diameter with 5.9 inch stroke, the cylinders being cast in two +pairs. The overhead arrangement of valves was adopted, and in later +designs push-rods were eliminated, the overhead cam-shaft being adopted +in their place. By 1914 the four-cylinder Mercedes-Daimler had been +partially displaced from favour by a six-cylindered model, made in two +sizes; the first of these gave a nominal brake horse-power of 80, having +cylinders of 4.1 inches diameter by 5.5 inches stroke; the second type +developed 100 horse-power with cylinders 4.7 inches in diameter and 5.5 +inches stroke, both types being run at 1,200 revolutions per minute. The +cylinders of both these types were cast in pairs, and, instead of the +water jackets forming part of the casting, as in the design of the +original four-cylinder Mercedes-Daimler engine, they were made of steel +welded to flanges on the cylinders. Steel pistons, fitted with cast-iron +rings, were used, and the overhead arrangement of valves and cam-shaft +was adopted. About 0.55 pint per brake horse-power per hour was the +usual fuel consumption necessary to full load running, and the engine +was also economical as regards the consumption of lubricating oil, +the lubricating system being 'forced' for all parts, including the +cam-shaft. The shape of these engines was very well suited for work +with aircraft, being narrow enough to admit of a streamline form being +obtained, while all the accessories could be so mounted as to produce +little or no wind resistance, and very little obstruction to the pilot's +view. + +The eight-cylinder Mercedes-Daimler engine, used for airship propulsion +during the War, developed 240 brake horse-power at 1,100 revolutions per +minute; the cylinder dimensions were 6.88 diameter by 6.5 stroke--one +of the instances in which the short stroke in relation to bore was very +noticeable. + +Other instances of successful vertical design-the types already detailed +are fully sufficient to give particulars of the type generally--are +the Panhard, Chenu, Maybach, N.A.G., Argus, Mulag, and the well-known +Austro-Daimler, which by 1917 was being copied in every combatant +country. There are also the later Wright engines, and in America +the Wisconsin six-cylinder vertical, weighing well under 4 lbs. per +horse-power, is evidence of the progress made with this first type of +aero engine to develop. + + + + +II. THE VEE TYPE + +An offshoot from the vertical type, doubling the power of this with only +a very slight--if any--increase in the length of crankshaft, the Vee +or diagonal type of aero engine leaped to success through the insistent +demand for greater power. Although the design came after that of the +vertical engine, by 1910, according to Critchley's list of aero engines, +there were more Vee type engines being made than any other type, +twenty-five sizes being given in the list, with an average rating of +57.4 brake horse-power. + +The arrangement of the cylinders in Vee form over the crankshaft, +enabling the pistons of each pair of opposite cylinders to act upon the +same crank pin, permits of a very short, compact engine being built, and +also permits of reduction of the weight per horsepower, comparing this +with that of the vertical type of engine, with one row of cylinders. +Further, at the introduction of this type of engine it was seen that +crankshaft vibration, an evil of the early vertical engines, was +practically eliminated, as was the want of longitudinal stiffness that +characterised the higher-powered vertical engines. + +Of the Vee type engines shown in Critchley's list in 1910 nineteen +different sizes were constructed with eight cylinders, and with +horse-powers ranging from thirty to just over the hundred; the lightest +of these weighed 2.9 lbs. per horse-power--a considerable advance in +design on the average vertical engine, in this respect of weight per +horse-power. There were also two sixteen-cylinder engines of Vee design, +the larger of which developed 134 horse-power with a weight of only 2 +lbs. per brake horse-power. Subsequent developments have indicated that +this type, with the further development from it of the double-Vee, or +engine with three rows of cylinders, is likely to become the standard +design of aero engine where high powers are required. The construction +permits of placing every part so that it is easy of access, and the +form of the engine implies very little head resistance, while it can be +placed on the machine--supposing that machine to be of the single-engine +type--in such a way that the view of the pilot is very little obstructed +while in flight. + +An even torque, or great uniformity of rotation, is transmitted to the +air-screw by these engines, while the design also permits of such good +balance of the engine itself that vibration is practically eliminated. +The angle between the two rows of cylinders is varied according to the +number of cylinders, in order to give working impulses at equal angles +of rotation and thus provide even torque; this angle is determined by +dividing the number of degrees in a circle by the number of cylinders +in either row of the engine. In an eight-cylindered Vee type engine, the +angle between the cylinders is 90 degrees; if it is a twelve-cylindered +engine, the angle drops to 60 degrees. + +One of the earliest of the British-built Vee type engines was an +eight-cylinder 50 horse-power by the Wolseley Company, constructed in +1908 with a cylinder bore of 3.75 inches and stroke of 5 inches, running +at a normal speed of 1,350 revolutions per minute. With this engine, a +gearing was introduced to enable the propeller to run at a lower speed +than that of the engine, the slight loss of efficiency caused by the +friction of the gearing being compensated by the slower speed of the +air-screw, which had higher efficiency than would have been the case if +it had been run at the engine speed. The ratio of the gearing--that is, +the speed of the air-screw relatively to that of the engine, could be +chosen so as to suit exactly the requirements of the air-screw, and the +gearing itself, on this engine, was accomplished on the half-speed shaft +actuating the valves. + +Very soon after this first design had been tried out, a second Vee type +engine was produced which, at 1,200 revolutions per minute, developed 60 +horse-power; the size of this engine was practically identical with that +of its forerunner, the only exception being an increase of half an inch +in the cylinder stroke--a very long stroke of piston in relation to +the bore of the cylinder. In the first of these two engines, which was +designed for airship propulsion, the weight had been about 8 lbs. per +brake horse-power, no special attempt appearing to have been made to +fine down for extreme lightness; in this 60 horse-power design, the +weight was reduced to 6.1 lbs. per horse-power, counting the latter +as normally rated; the engine actually gave a maximum of 75 brake +horse-power, reducing the ratio of weight to power very considerably +below the figure given. + +The accompanying diagram illustrates a later Wolseley model, end +elevation, the eight-cylindered 120 horse-power Vee type aero engine +of the early war period. With this engine, each crank pin has two +connecting rods bearing on it, these being placed side by side and +connected to the pistons of opposite cylinders and the two cylinders of +the pair are staggered by an amount equal to the width of the connecting +rod bearing, to afford accommodation for the rods. The crankshaft was a +nickel chrome steel forging, machined hollow, with four crank pins set +at 180 degrees to each other, and carried in three bearings lined with +anti-friction metal. The connecting rods were made of tubular nickel +chrome steel, and the pistons of drawn steel, each being fitted with +four piston rings. Of these the two rings nearest to the piston head +were of the ordinary cast-iron type, while the others were of phosphor +bronze, so arranged as to take the side thrust of the piston. The +cylinders were of steel, arranged in two groups or rows of four, the +angular distance between them being 90 degrees. In the space above the +crankshaft, between the cylinder rows, was placed the valve-operating +mechanism, together with the carburettor and ignition system, thus +rendering this a very compact and accessible engine. The combustion +heads of the cylinders were made of cast-iron, screwed into the steel +cylinder barrels; the water-jacket was of spun aluminium, with one end +fitting over the combustion head and the other free to slide on the +cylinder; the water-joint at the lower end was made tight by a Dermatine +ring carried between small flanges formed on the cylinder barrel. +Overhead valves were adopted, and in order to make these as large as +possible the combustion chamber was made slightly larger in diameter +than the cylinder, and the valves set at an angle. Dual ignition was +fitted in each cylinder, coil and accumulator being used for starting +and as a reserve in case of failure of the high-tension magneto system +fitted for normal running. There was a double set of lubricating pumps, +ensuring continuity of the oil supply to all the bearings of the engine. + +The feature most noteworthy in connection with the running of this type +of engine was its flexibility; the normal output of power was +obtained with 1,150 revolutions per minute of the crankshaft, but, by +accelerating up to 1,400 revolutions, a maximum of 147 brake horse-power +could be obtained. The weight was about 5 lbs. per horse-power, the +cylinder dimensions being 5 inches bore by 7 inches stroke. Economy in +running was obtained, the fuel consumption being 0.58 pint per brake +horse-power per hour at full load, with an expenditure of about 0.075 +pint of lubricating oil per brake horse-power per hour. + +Another Wolseley Vee type that was standardised was a 90 horse-power +eight-cylinder engine running at 1,800 revolutions per minute, with +a reducing gear introduced by fitting the air screw on the half-speed +shaft. First made semi-cooled--the exhaust valve was left air-cooled, +and then entirely water-jacketed--this engine demonstrated the advantage +of full water cooling, for under the latter condition the same power was +developed with cylinders a quarter of an inch less in diameter than in +the semi-cooled pattern; at the same time the weight was brought down to +4 1/2 lbs. per horsepower. + +A different but equally efficient type of Vee design was the Dorman +engine, of which an end elevation is shown; this developed 80 brake +horse-power at a speed of 1,300 revolutions per minute, with a cylinder +bore of 5 inches; each cylinder was made in cast-iron in one piece with +the combustion chamber, the barrel only being water-jacketed. Auxiliary +exhaust ports were adopted, the holes through the cylinder wall being +uncovered by the piston at the bottom of its stroke--the piston, 4.75 +inches in length, was longer than its stroke, so that these ports were +covered when it was at the top of the cylinder. The exhaust discharged +through the ports into a belt surrounding the cylinder, the belts on the +cylinders being connected so that the exhaust gases were taken through +a single pipe. The air was drawn through the crank case, before reaching +the carburettor, this having the effect of cooling the oil in the crank +case as well as warming the air and thus assisting in vaporising the +petrol for each charge of the cylinders. The inlet and exhaust valves +were of the overhead type, as may be gathered from the diagram, and in +spite of cast-iron cylinders being employed a light design was obtained, +the total weight with radiator, piping, and water being only 5.5 lbs. +per horse-power. + +Here was the antithesis of the Wolseley type in the matter of bore in +relation to stroke; from about 1907 up to the beginning of the war, and +even later, there was controversy as to which type--that in which the +bore exceeded the stroke, or vice versa--gave greater efficiency. +The short-stroke enthusiasts pointed to the high piston speed of the +long-stroke type, while those who favoured the latter design contended +that full power could not be obtained from each explosion in the +short-stroke type of cylinder. It is now generally conceded that the +long-stroke engine yields higher efficiency, and in addition to this, +so far as car engines are concerned, the method of rating horse-power +in relation to bore without taking stroke into account has given the +long-stroke engine an advantage, actual horse-power with a long stroke +engine being in excess of the nominal rating. This may have had some +influence on aero engine design, but, however this may have been, the +long-stroke engine has gradually come to favour, and its rival has taken +second place. + +For some time pride of place among British Vee type engines was held +by the Sunbeam Company, which, owing to the genius of Louis Coatalen, +together with the very high standard of construction maintained by the +firm, achieved records and fame in the middle and later periods of the +war. Their 225 horse-power twelve-cylinder engine ran at a normal +speed of 2,000 revolutions per minute; the air screw was driven through +gearing at half this speed, its shaft being separate from the timing +gear and carried in ball-bearings on the nose-piece of the engine. The +cylinders were of cast-iron, entirely water-cooled; a thin casing formed +the water-jacket, and a very light design was obtained, the weight being +only 3.2 lbs. per horse-power. The first engine of Sunbeam design had +eight cylinders and developed 150 horse-power at 2,000 revolutions +per minute; the final type of Vee design produced during the war was +twelve-cylindered, and yielded 310 horse-power with cylinders 4.3 inches +bore by 6.4 inches stroke. Evidence in favour of the long-stroke engine +is afforded in this type as regards economy of working; under full load, +working at 2,000 revolutions per minute, the consumption was 0.55 pints +of fuel per brake horse-power per hour, which seems to indicate that the +long stroke permitted of full use being made of the power resulting from +each explosion, in spite of the high rate of speed of the piston. + +Developing from the Vee type, the eighteen-cylinder 475 brake +horse-power engine, designed during the war, represented for a time +the limit of power obtainable from a single plant. It was water-cooled +throughout, and the ignition to each cylinder was duplicated; this +engine proved fully efficient, and economical in fuel consumption. +It was largely used for seaplane work, where reliability was fully as +necessary as high power. + +The abnormal needs of the war period brought many British firms into the +ranks of Vee-type engine-builders, and, apart from those mentioned, +the most notable types produced are the Rolls-Royce and the Napier. +The first mentioned of these firms, previous to 1914 had concentrated +entirely on car engines, and their very high standard of production in +this department of internal combustion engine work led, once they took +up the making of aero engines, to extreme efficiency both of design and +workmanship. The first experimental aero engine, of what became known +as the 'Eagle' type, was of Vee design--it was completed in March +of 1915--and was so successful that it was standardised for quantity +production. How far the original was from the perfection subsequently +ascertained is shown by the steady increase in developed horse-power +of the type; originally designed to develop 200 horse-power, it was +developed and improved before its first practical trial in October of +1915, when it developed 255 horsepower on a brake test. Research +and experiment produced still further improvements, for, without any +enlargement of the dimensions, or radical alteration in design, the +power of the engine was brought up to 266 horse-power by March of 1916, +the rate of revolutions of 1,800 per minute being maintained throughout. +July, 1916 gave 284 horse-power; by the cud of the year this had been +increased to 322 horse-power; by September of 1917 the increase was to +350 horse-power, and by February of 1918 then 'Eagle' type of engine was +rated at 360 horse-power, at which standard it stayed. But there is no +more remarkable development in engine design than this, a 75 per cent +increase of power in the same engine in a period of less than three +years. + +To meet the demand for a smaller type of engine for use on training +machines, the Rolls-Royce firm produced the 'Hawk' Vee-type engine of +100 horsepower, and, intermediately between this and the 'Eagle,' the +'Falcon' engine came to being with an original rated horse-power of 205 +at 1,800 revolutions per minute, in April of 1916. Here was another case +of growth of power in the same engine through research, almost similar +to that of the 'Eagle' type, for by July of 1918 the 'Falcon' was +developing 285 horse-power with no radical alteration of design. +Finally, in response to the constant demand for increase of power in a +single plant, the Rolls-Royce company designed and produced the 'Condor' +type of engine, which yielded 600 horse-power on its first test in +August of 1918. The cessation of hostilities and consequent falling off +in the demand for extremely high-powered plants prevented the 'Condor' +being developed to its limit, as had been the 'Falcon' and 'Eagle' +types. + +The 'Eagle 'engine was fitted to the two Handley-Page aeroplanes--which +made flights from England to India--it was virtually standard on the +Handley-Page bombers of the later War period, though to a certain extent +the American 'Liberty' engine was also used. Its chief record, however, +is that of being the type fitted to the Vickers-Vimy aeroplane which +made the first Atlantic flight, covering the distance of 1,880 miles at +a speed averaging 117 miles an hour. + +The Napier Company specialised on one type of engine from the outset, +a power plant which became known as the 'Lion' engine, giving 450 +horse-power with twelve cylinders arranged in three rows of four each. +Considering the engine as 'dry,' or without fuel and accessories, an +abnormally light weight per horse-power--only 1.89 lbs.--was attained +when running at the normal rate of revolution. The cylinders and +water-jackets are of steel, and there is fitted a detachable aluminium +cylinder head containing inlet and exhaust valves and valve actuating +mechanism; pistons are of aluminium alloy, and there are two inlet and +two exhaust valves to each cylinder, the whole of the valve mechanism +being enclosed in an oil-tight aluminium case. Connecting rods and +crankshaft are of steel, the latter being machined from a solid steel +forging and carried in five roller bearings and one plain bearing at the +forward end. The front end of the crank-case encloses reduction gear for +the propeller shaft, together with the shaft and bearings. There are +two suction and one pressure type oil pumps driven through gears at +half-engine speed, and two 12 spark magnetos, giving 2 sparks in each +cylinder. + +The cylinders are set with the central row vertical, and the two side +rows at angles of 60 degrees each; cylinder bore is 5 1/2 inches, and +stroke 5 1/8 inches; the normal rate of revolution is 1,350 per minute, +and the reducing gear gives one revolution of the propeller shaft to +1.52 revolutions of crankshaft. Fuel consumption is 0.48lbs. of fuel per +brake horse-power hour at full load, and oil consumption is 0.020 lbs. +per brake horsepower hour. The dry weight of the engine, complete with +propeller boss, carburettors, and induction pipes, is 850 lbs., and the +gross weight in running order, with fuel and oil for six hours working, +is 2,671 lbs., exclusive of cooling water. + +To this engine belongs an altitude record of 30,500 feet, made at +Martlesham, near Ipswich, on January 2nd, 1919, by Captain Lang, R.A.F., +the climb being accomplished in 66 minutes 15 seconds. Previous to this, +the altitude record was held by an Italian pilot, who made 25,800 feet +in an hour and 57 minutes in 1916. Lang's climb was stopped through +the pressure of air, at the altitude he reached, being insufficient for +driving the small propellers on the machine which worked the petrol and +oil pumps, or he might have made the height said to have been attained +by Major Schroeder on February 27th, 1920, at Dayton, Ohio. Schroeder +is said to have reached an altitude of 36,020 feet on a Napier biplane, +and, owing to failure of the oxygen supply, to have lost consciousness, +fallen five miles, righted his machine when 2,000 feet in the air, and +alighted successfully. Major Schroeder is an American. + +Turning back a little, and considering other than British design of Vee +and double-Vee or 'Broad arrow' type of engine, the Renault firm from +the earliest days devoted considerable attention to the development of +this type, their air-cooled engines having been notable examples from +the earliest days of heavier-than-air machines. In 1910 they were making +three sizes of eight-cylindered Vee-type engines, and by 1915 they had +increased to the manufacture of five sizes, ranging from 25 to 100 brake +horse-power, the largest of the five sizes having twelve cylinders but +still retaining the air-cooled principle. The De Dion firm, also, +made Vee-type engines in 1914, being represented by an 80 horse-power +eight-cylindered engine, air-cooled, and a 150 horse-power, also +of eight cylinders, water-cooled, running at a normal rate of 1,600 +revolutions per minute. Another notable example of French construction +was the Panhard and Levassor 100 horse-power eight-cylinder Vee engine, +developing its rated power at 1,500 revolutions per minute, and having +the--for that time--low weight of 4.4 lbs. per horse-power. + +American Vee design has followed the British fairly cclosely; the +Curtiss Company produced originally a 75 horse-power eight-cylinder Vee +type running at 1,200 revolutions per minute, supplementing this with +a 170 horse-power engine running at 1,600 revolutions per minute, and +later with a twelve-cylinder model Vee type, developing 300 horse-power +at 1,500 revolutions per minute, with cylinder bore of 5 inches and +stroke of 7 inches. An exceptional type of American design was the Kemp +Vee engine of 80 horse-power in which the cylinders were cooled by a +current of air obtained from a fan at the forward end of the engine. +With cylinders of 4.25 inches bore and 4.75 inches stroke, the rater +power was developed at 1,150 revolutions per minute, and with the engine +complete the weight was only 4.75 lbs. per horse-power. + + + + +III. THE RADIAL TYPE + +The very first successful design of internal combustion aero engine made +was that of Charles Manly, who built a five-cylinder radial engine in +1901 for use with Langley's 'aerodrome,' as the latter inventor decided +to call what has since become known as the aeroplane. Manly made a +number of experiments, and finally decided on radial design, in which +the cylinders are so rayed round a central crank-pin that the pistons +act successively upon it; by this arrangement a very short and compact +engine is obtained, with a minimum of weight, and a regular crankshaft +rotation and perfect balance of inertia forces. + +When Manly designed his radial engine, high speed internal combustion +engines were in their infancy, and the difficulties in construction +can be partly realised when the lack of manufacturing methods for this +high-class engine work, and the lack of experimental data on the various +materials, are taken into account. During its tests, Manly's engine +developed 52.4 brake horsepower at a speed of 950 revolutions per +minute, with the remarkably low weight of only 2.4 lbs. per horsepower; +this latter was increased to 3.6 lbs. when the engine was completed +by the addition of ignition system, radiator, petrol tank, and all +accessories, together with the cooling water for the cylinders. + +In Manly's engine, the cylinders were of steel, machined outside and +inside to 1/16 of an inch thickness; on the side of cylinder, at the top +end, the valve chamber was brazed, being machined from a solid forging, +The casing which formed the water-jacket was of sheet steel, 1/50 of an +inch in thickness, and this also was brazed on the cylinder and to +the valve chamber. Automatic inlet valves were fitted, and the exhaust +valves were operated by a cam which had two points, 180 degrees +apart; the cam was rotated in the opposite direction to the engine at +one-quarter engine speed. Ignition was obtained by using a one-spark +coil and vibrator for all cylinders, with a distributor to select +the right cylinder for each spark--this was before the days of the +high-tension magneto and the almost perfect ignition systems that makers +now employ. The scheme of ignition for this engine was originated by +Manly himself, and he also designed the sparking plugs fitted in the +tops of the cylinders. Through fear of trouble resulting if the steel +pistons worked on the steel cylinders, cast iron liners were introduced +in the latter, 1/16 of an inch thick. + +The connecting rods of this engine were of virtually the same type as is +employed on nearly all modern radial engines. The rod for one cylinder +had a bearing along the whole of the crank pin, and its end enclosed the +pin; the other four rods had bearings upon the end of the first rod, +and did not touch the crank pin. The accompanying diagram shows this +construction, together with the means employed for securing the ends of +the four rods--the collars were placed in position after the rods had +been put on. The bearings of these rods did not receive any of the +rubbing effect due to the rotation of the crank pin, the rubbing on them +being only that of the small angular displacement of the rods during +each revolution; thus there was no difficulty experienced with the +lubrication. + +Another early example of the radial type of engine was the French +Anzani, of which type one was fitted to the machine with which Bleriot +first crossed the English Channel--this was of 25 horse-power. The +earliest Anzani engines were of the three-cylinder fan type, one +cylinder being vertical, and the other two placed at an angle of 72 +degrees on each side, as the possibility of over-lubrication of the +bottom cylinders was feared if a regular radial construction were +adopted. In order to overcome the unequal balance of this type, balance +weights were fitted inside the crank case. + +The final development of this three-cylinder radial was the 'Y' type of +engine, in which the cylinders were regularly disposed at 120 degrees +apart, the bore was 4.1, stroke 4.7 inches, and the power developed was +30 brake horse-power at 1,300 revolutions per minute. + +Critchley's list of aero engines being constructed in 1910 shows twelve +of the radial type, with powers of between 14 and 100 horse-power, and +with from three to ten cylinder--this last is probably the greatest +number of cylinders that can be successfully arranged in circular form. +Of the twelve types of 1910, only two were water-cooled, and it is to be +noted that these two ran at the slowest speeds and had the lowest weight +per horse-power of any. + +The Anzani radial was considerably developed special attention being +paid to this type by its makers and by 1914 the Anzani list comprised +seven different sizes of air-cooled radials. Of these the largest had +twenty cylinders, developing 200 brake horse-power--it was virtually +a double radial--and the smallest was the original 30 horse-power +three-cylinder design. A six-cylinder model was formed by a combination +of two groups of three cylinders each, acting upon a double-throw +crankshaft; the two crank pins were set at 180 degrees to each other, +and the cylinder groups were staggered by an amount equal to the +distance between the centres of the crank pins. Ten-cylinder radial +engines are made with two groups of five cylinders acting upon two +crank pins set at 180 degrees to each other, the largest Anzani 'ten' +developed 125 horsepower at 1,200 revolutions per minute, the ten +cylinders being each 4.5 inches in bore with stroke of 5.9 inches, and +the weight of the engine being 3.7 lbs. per horse-power. In the 200 +horse-power Anzani radial the cylinders are arranged in four groups of +five each, acting on two crank pins. The bore of the cylinders in this +engine is the same as in the three-cylinder, but the stroke is increased +to 5.5 inches. The rated power is developed at 1,300 revolutions per +minute, and the engine complete weighs 3.4 lbs. per horse-power. + +With this 200 horse-power Anzani, a petrol consumption of as low as 0.49 +lbs. of fuel per brake horse-power per hour has been obtained, but +the consumption of lubricating oil is compensatingly high, being up to +one-fifth of the fuel used. The cylinders are set desaxe with the +crank shaft, and are of cast-iron, provided with radiating ribs for +air-cooling; they are attached to the crank case by long bolts passing +through bosses at the top of the cylinders, and connected to other bolts +at right angles through the crank case. The tops of the cylinders are +formed flat, and seats for the inlet and exhaust valves are formed on +them. The pistons are cast-iron, fitted with ordinary cast-iron spring +rings. An aluminium crank case is used, being made in two halves +connected together by bolts, which latter also attach the engine to the +frame of the machine. The crankshaft is of nickel steel, made hollow, +and mounted on ball-bearings in such a manner that practically a +combination of ball and plain bearings is obtained; the central web +of the shaft is bent to bring the centres of the crank pins as close +together as possible, leaving only room for the connecting rods, and +the pins are 180 degrees apart. Nickel steel valves of the cone-seated, +poppet type are fitted, the inlet valves being automatic, and those for +the exhaust cam-operated by means of push-rods. With an engine having +such a number of cylinders a very uniform rotation of the crankshaft is +obtained, and in actual running there are always five of the cylinders +giving impulses to the crankshaft at the same time. + +An interesting type of pioneer radial engine was the Farcot, in which +the cylinders were arranged in a horizontal plane, with a vertical +crankshaft which operated the air-screw through bevel gearing. This was +an eight-cylinder engine, developing 64 horse-power at 1,200 revolutions +per minute. The R.E.P. type,in the early days, was a 'fan' engine, +but the designer, M. Robert Pelterie, turned from this design to a +seven-cylinder radial, which at 1,100 revolutions per minute gave 95 +horse-power. Several makers entered into radial engine development in +the years immediately preceding the War, and in 1914 there were +some twenty-two different sizes and types, ranging from 30 to 600 +horse-power, being made, according to report; the actual construction of +the latter size at this time, however, is doubtful. + +Probably the best example of radial construction up to the outbreak of +War was the Salmson (Canton-Unne) water-cooled, of which in 1914 +six sizes were listed as available. Of these the smallest was a +seven-cylinder 90 horse-power engine, and the largest, rated at 600 +horse-power, had eighteen cylinders. These engines, during the War, were +made under license by the Dudbridge Ironworks in Great Britain. + +The accompanying diagram shows the construction of the cylinders in the +200 horse-power size, showing the method of cooling, and the arrangement +of the connecting rods. A patent planetary gear, also shown in the +diagram, gives exactly the same stroke to all the pistons. The complete +engine has fourteen cylinders, of forged steel machined all over, and +so secured to the crank case that any one can be removed without parting +the crank case. The water-jackets are of spun copper, brazed on to the +cylinder, and corrugated so as to admit of free expansion; the water is +circulated by means of a centrifugal pump. The pistons are of cast-iron, +each fitted with three rings, and the connecting rods are of high grade +steel, machined all over and fitted with bushes of phosphor bronze; +these rods are connected to a central collar, carried on the crank pin +by two ball-bearings. The crankshaft has a single throw, and is made +in two parts to allow the cage for carrying the big end-pins of the +connecting rods to be placed in position. + +The casing is in two parts, on one of which the brackets for fixing the +engine are carried, while the other part carries the valve-gear. Bolts +secure the two parts together. The mechanically-operated steel valves +on the cylinders are each fitted with double springs and the valves are +operated by rods and levers. Two Zenith carburettors are fitted on the +rear half of the crank case, and short induction pipes are led to each +cylinder; each of the carburettors is heated by the exhaust gases. +Ignition is by two high-tension magnetos, and a compressed air +self-starting arrangement is provided. Two oil pumps are fitted for +lubricating purposes, one of which forces oil to the crankshaft and +connecting-rod bearings, while the second forces oil to the valve gear, +the cylinders being so arranged that the oil which flows along the walls +cannot flood the lower cylinders. This engine operates upon a six-stroke +cycle, a rather rare arrangement for internal combustion engines of the +electrical ignition type; this is done in order to obtain equal angular +intervals for the working impulses imparted to the rotating crankshaft, +as the cylinders are arranged in groups of seven, and all act upon the +one crankshaft. The angle, therefore, between the impulses is 77 1/7 +degrees. A diagram is inset giving a side view of the engine, in order +to show the grouping of the cylinders. + +The 600 horse-power Salmson engine was designed with a view to fitting +to airships, and was in reality two nine-cylindered engines, with a +gear-box connecting them; double air-screws were fitted, and these were +so arranged that either or both of them might be driven by either or +both engines; in addition to this, the two engines were complete and +separate engines as regards carburation and ignition, etc., so that +they could be run independently of each other. The cylinders were +exceptionally 'long stroke,' being 5.9 inches bore to 8.27 inches +stroke, and the rated power was developed at 1,200 revolutions per +minute, the weight of the complete engine being only 4.1 lbs. per +horse-power at the normal rating. + +A type of engine specially devised for airship propulsion is that in +which the cylinders are arranged horizontally instead of vertically, the +main advantages of this form being the reduction of head resistance and +less obstruction to the view of the pilot. A casing, mounted on the top +of the engine, supports the air-screw, which is driven through bevel +gearing from the upper end of the crankshaft. With this type of engine +a better rate of air-screw efficiency is obtained by gearing the screw +down to half the rate of revolution of the engine, this giving a more +even torque. The petrol consumption of the type is very low, being only +0.48 lbs. per horse-power per hour, and equal economy is claimed as +regards lubricating oil, a consumption of as little as 0.04 lbs. per +horse-power per hour being claimed. + +Certain American radial engines were made previous to 1914, the +principal being the Albatross six-cylinder engines of 50 and 100 +horse-powers. Of these the smaller size was air-cooled, with cylinders +of 4.5 inches bore and 5 inches stroke, developing the rated power +at 1,230 revolutions per minute, with a weight of about 5 lbs. per +horse-power. The 100 horse-power size had cylinders of 5.5 inches bore, +developing its rated power at 1,230 revolutions per minute, and weighing +only 2.75 lbs. per horse-power. This engine was markedly similar to the +six-cylindered Anzani, having all the valves mechanically operated, and +with auxiliary exhaust ports at the bottoms of the cylinders, overrun +by long pistons. These Albatross engines had their cylinders arranged in +two groups of three, with each group of three pistons operating on one +of two crank pins, each 180 degrees apart. + +The radial type of engine, thanks to Charles Manly, had the honour of +being first in the field as regards aero work. Its many advantages, +among which may be specially noted the very short crankshaft as compared +with vertical, Vee, or 'broad arrow' type of engine, and consequent +greater rigidity, ensure it consideration by designers of to-day, and +render it certain that the type will endure. Enthusiasts claim that the +'broad arrow' type, or Vee with a third row of cylinders inset between +the original two, is just as much a development from the radial engine +as from the vertical and resulting Vee; however this may be, there is +a place for the radial type in air-work for as long as the internal +combustion engine remains as a power plant. + + + + +IV. THE ROTARY TYPE + +M. Laurent Seguin, the inventor of the Gnome rotary aero engine, +provided as great a stimulus to aviation as any that was given anterior +to the war period, and brought about a great advance in mechanical +flight, since these well-made engines gave a high-power output for their +weight, and were extremely smooth in running. In the rotary design the +crankshaft of the engine is stationary, and the cylinders, crank +case, and all their adherent parts rotate; the working is thus exactly +opposite in principle to that of the radial type of aero engine, and +the advantage of the rotary lies in the considerable flywheel effect +produced by the revolving cylinders, with consequent evenness of torque. +Another advantage is that air-cooling, adopted in all the Gnome engines, +is rendered much more effective by the rotation of the cylinders, though +there is a tendency to distortion through the leading side of each +cylinder being more efficiently cooled than the opposite side; advocates +of other types are prone to claim that the air resistance to the +revolving cylinders absorbs some 10 per cent of the power developed by +the rotary engine, but that has not prevented the rotary from attaining +to great popularity as a prime mover. + +There were, in the list of aero engines compiled in 1910, five rotary +engines included, all air-cooled. Three of these were Gnome engines, and +two of the make known as 'International.' They ranged from 21.5 to 123 +horse-power, the latter being rated at only 1.8 lbs. weight per brake +horse-power, and having fourteen cylinders, 4.33 inches in diameter +by 4.7 inches stroke. By 1914 forty-three different sizes and types +of rotary engine were being constructed, and in 1913 five rotary type +engines were entered for the series of aeroplane engine trials held +in Germany. Minor defects ruled out four of these, and only the +German Bayerischer Motoren Flugzeugwerke completed the seven-hour test +prescribed for competing engines. Its large fuel consumption barred this +engine from the final trials, the consumption being some 0.95 pints +per horse-power per hour. The consumption of lubricating oil, also was +excessive, standing at 0.123 pint per horse-power per hour. The engine +gave 37.5 effective horse-power during its trial, and the loss due to +air resistance was 4.6 horse-power, about 11 per cent. The accompanying +drawing shows the construction of the engine, in which the seven +cylinders are arranged radially on the crank case; the method of +connecting the pistons to the crank pins can be seen. The mixture is +drawn through the crank chamber, and to enter the cylinder it passes +through the two automatic valves in the crown of the piston; the exhaust +valves are situated in the tops of the cylinders, and are actuated by +cams and push-rods. Cooling of the cylinder is assisted by the radial +rings, and the diameter of these rings is increased round the hottest +part of the cylinder. When long flights are undertaken the advantage of +the light weight of this engine is more than counterbalanced by its high +fuel and lubricating oil consumption, but there are other makes which +are much better than this seven-cylinder German in respect of this. + +Rotation of the cylinders in engines of this type is produced by the +side pressure of the pistons on the cylinder walls, and in order to +prevent this pressure from becoming abnormally large it is necessary +to keep the weight of the piston as low as possible, as the pressure is +produced by the tangential acceleration and retardation of the piston. +On the upward stroke the circumferential velocity of the piston is +rapidly increased, which causes it to exert a considerable tangential +pressure on the side of the cylinder, and on the return stroke there +is a corresponding retarding effect due to the reduction of the +circumferential velocity of the piston. These side pressures cause an +appreciable increase in the temperatures of the cylinders and pistons, +which makes it necessary to keep the power rating of the engines fairly +low. + +Seguin designed his first Gnome rotary as a 34 horse-power engine when +run at a speed of 1,300 revolutions per minute. It had five cylinders, +and the weight was 3.9 lbs. per horse-power. A seven-cylinder model soon +displaced this first engine, and this latter, with a total weight of 165 +lbs., gave 61.5 horse-power. The cylinders were machined out of solid +nickel chrome-steel ingots, and the machining was carried out so that +the cylinder walls were under 1/6 of an inch in thickness. The pistons +were cast-iron, fitted each with two rings, and the automatic inlet +valve to the cylinder was placed in the crown of the piston. The +connecting rods, of 'H' section, were of nickel chrome-steel, and the +large end of one rod, known as the 'master-rod' embraced the crank pin; +on the end of this rod six hollow steel pins were carried, and to these +the remaining six connecting-rods were attached. The crankshaft of the +engine was made of nickel chrome-steel, and was in two parts connected +together at the crank pin; these two parts, after the master-rod had +been placed in position and the other connecting rods had been attached +to it, were firmly secured. The steel crank case was made in five parts, +the two central ones holding the cylinders in place, and on one side +another of the five castings formed a cam-box, to the outside of which +was secured the extension to which the air-screw was attached. On the +other side of the crank case another casting carried the thrust-box, and +the whole crank case, with its cylinders and gear, was carried on the +fixed crank shaft by means of four ball-bearings, one of which also took +the axial thrust of the air-screw. + +For these engines, castor oil is the lubricant usually adopted, and it +is pumped to the crankshaft by means of a gear-driven oil pump; from +this shaft the other parts of the engine are lubricated by means of +centrifugal force, and in actual practice sufficient unburnt oil passes +through the cylinders to lubricate the exhaust valve, which partly +accounts for the high rate of consumption of lubricating oil. A very +simple carburettor of the float less, single-spray type was used, and +the mixture was passed along the hollow crankshaft to the interior of +the crank case, thence through the automatic inlet valves in the tops of +the pistons to the combustion chambers of the cylinders. Ignition was +by means of a high-tension magneto specially geared to give the correct +timing, and the working impulses occurred at equal angular intervals of +102.85 degrees. The ignition was timed so that the firing spark occurred +when the cylinder was 26 degrees before the position in which the piston +was at the outer end of its stroke, and this timing gave a maximum +pressure in the cylinder just after the piston had passed this position. + +By 1913, eight different sizes of the Gnome engine were being +constructed, ranging from 45 to 180 brake horse-power; four of these +were single-crank engines one having nine and the other three having +seven cylinders. The remaining four were constructed with two cranks; +three of them had fourteen cylinders apiece, ranged in groups of seven, +acting on the cranks, and the one other had eighteen cylinders ranged in +two groups of nine, acting on its two cranks. Cylinders of the two-crank +engines are so arranged (in the fourteen-cylinder type) that fourteen +equal angular impulses occur during each cycle; these engines are +supported on bearings on both sides of the engine, the air-screw being +placed outside the front support. In the eighteen-cylinder model the +impulses occur at each 40 degrees of angular rotation of the cylinders, +securing an extremely even rotation of the air-screw. + +In 1913 the Gnome Monosoupape engine was introduced, a model in which +the inlet valve to the cylinder was omitted, while the piston was of the +ordinary cast-iron type. A single exhaust valve in the cylinder head was +operated in a manner similar to that on the previous Gnome engines, and +the fact of this being the only valve on the cylinder gave the engine +its name. Each cylinder contained ports at the bottom which communicated +with the crank chamber, and were overrun by the piston when this was +approaching the bottom end of its stroke. During the working cycle of +the engine the exhaust valve was opened early to allow the exhaust gases +to escape from the cylinder, so that by the time the piston overran the +ports at the bottom the pressure within the cylinder was approximately +equal to that in the crank case, and practically no flow of gas took +place in either direction through the ports. The exhaust valve remained +open as usual during the succeeding up-stroke of the piston, and +the valve was held open until the piston had returned through about +one-third of its downward stroke, thus permitting fresh air to enter the +cylinder. The exhaust valve then closed, and the downward motion of the +piston, continuing, caused a partial vacuum inside the cylinder; when +the piston overran the ports, the rich mixture from the crank case +immediately entered. The cylinder was then full of the mixture, and the +next upward stroke of the piston compressed the charge; upon ignition +the working cycle was repeated. The speed variation of this engine +was obtained by varying the extent and duration of the opening of the +exhaust valves, and was controlled by the pilot by hand-operated levers +acting on the valve tappet rollers. The weight per horsepower of these +engines was slightly less than that of the two-valve type, while the +lubrication of the gudgeon pin and piston showed an improvement, so that +a lower lubricating oil consumption was obtained. The 100 horse-power +Gnome Monosoupape was built with nine cylinders, each 4.33 inches +bore by 5.9 inches stroke, and it developed its rated power at 1,200 +revolutions per minute. + +An engine of the rotary type, almost as well known as the Gnome, is the +Clerget, in which both cylinders and crank case are made of steel, the +former having the usual radial fins for cooling. In this type the +inlet and exhaust valves are both located in the cylinder head, and +mechanically operated by push-rods and rockers. Pipes are carried from +the crank case to the inlet valve casings to convey the mixture to the +cylinders, a carburettor of the central needle type being used. The +carburetted mixture is taken into the crank case chamber in a manner +similar to that of the Gnome engine. Pistons of aluminium alloy, with +three cast-iron rings, are fitted, the top ring being of the obturator +type. The large end of one of the nine connecting rods embraces the +crank pin and the pressure is taken on two ball-bearings housed in the +end of the rod. This carries eight pins, to which the other rods are +attached, and the main rod being rigid between the crank pin and piston +pin determines the position of the pistons. Hollow connecting-rods +are used, and the lubricating oil for the piston pins passes from the +crankshaft through the centres of the rods. Inlet and exhaust valves +can be set quite independently of one another--a useful point, since +the correct timing of the opening of these valves is of importance. The +inlet valve opens 4 degrees from top centre and closes after the bottom +dead centre of the piston; the exhaust valve opens 68 degrees before +the bottom centre and closes 4 degrees after the top dead centre of the +piston. The magnetos are set to give the spark in the cylinder at 25 +degrees before the end of the compression stroke--two high-tension +magnetos are used: if desired, the second one can be adjusted to give +a later spark for assisting the starting of the engine. The lubricating +oil pump is of the valveless two-plunger type, so geared that it runs +at seven revolutions to 100 revolutions of the engine; by counting +the pulsations the speed of the engine can be quickly calculated by +multiplying the pulsations by 100 and dividing by seven. In the 115 +horse-power nine-cylinder Clerget the cylinders are 4.7 bore with a 6.3 +inches stroke, and the rated power of the engine is obtained at +1,200 revolutions per minute. The petrol consumption is 0.75 pint per +horse-power per hour. + +A third rotary aero engine, equally well known with the foregoing two, +is the Le Rhone, made in four different sizes with power outputs of from +50 to 160 horse-power; the two smaller sizes are single crank engines +with seven and nine cylinders respectively, and the larger sizes are +of double-crank design, being merely the two smaller sizes +doubled--fourteen and eighteen-cylinder engines. The inlet and +exhaust valves are located in the cylinder head, and both valves are +mechanically operated by one push-rod and rocker, radial pipes from +crank case to inlet valve casing taking the mixture to the cylinders. +The exhaust valves are placed on the leading, or air-screw side, of the +engine, in order to get the fullest possible cooling effect. The rated +power of each type of engine is obtained at 1,200 revolutions per +minute, and for all four sizes the cylinder bore is 4.13 inches, with +a 5.5 inches piston stroke. Thin cast-iron liners are shrunk into +the steel cylinders in order to reduce the amount of piston friction. +Although the Le Rhone engines are constructed practically throughout +of steel, the weight is only 2.9 lbs. per horse-power in the +eighteen-cylinder type. + +American enterprise in the construction of the rotary type is perhaps +best illustrated in the 'Gyro 'engine; this was first constructed with +inlet valves in the heads of the pistons, after the Gnome pattern, the +exhaust valves being in the heads of the cylinders. The inlet valve in +the crown of each piston was mechanically operated in a very ingenious +manner by the oscillation of the connecting-rod. The Gyro-Duplex engine +superseded this original design, and a small cross-section illustration +of this is appended. It is constructed in seven and nine-cylinder sizes, +with a power range of from 50 to 100 horse-power; with the largest size +the low weight of 2.5 lbs.. per horse-power is reached. The design is +of considerable interest to the internal combustion engineer, for it +embodies a piston valve for controlling auxiliary exhaust ports, which +also acts as the inlet valve to the cylinder. The piston uncovers the +auxiliary ports when it reaches the bottom of its stroke, and at the end +of the power stroke the piston is in such a position that the exhaust +can escape over the top of it. The exhaust valve in the cylinder head is +then opened by means of the push-rod and rocker, and is held open until +the piston has completed its upward stroke and returned through more +than half its subsequent return stroke. When the exhaust valve closes, +the cylinder has a charge of fresh air, drawn in through the exhaust +valve, and the further motion of the piston causes a partial vacuum; +by the time the piston reaches bottom dead centre the piston-valve has +moved up to give communication between the cylinder and the crank case, +therefore the mixture is drawn into the cylinder. Both the piston valve +and exhaust valve are operated by cams formed on the one casting, which +rotates at seven-eighths engine speed for the seven-cylinder type, and +nine-tenths engine speed for the nine-cylinder engines. Each of these +cams has four or five points respectively, to suit the number of +cylinders. + +The steel cylinders are machined from solid forgings and provided with +webs for air-cooling as shown. Cast-iron pistons are used, and are +connected to the crankshaft in the same manner as with the Gnome and Le +Rhone engines. Petrol is sprayed into the crank case by a small geared +pump and the mixture is taken from there to the piston valves by radial +pipes. Two separate pumps are used for lubrication, one forcing oil to +the crank-pin bearing and the other spraying the cylinders. + +Among other designs of rotary aero engines the E.J.C. is noteworthy, +in that the cylinders and crank case of this engine rotate in opposite +directions, and two air-screws are used, one being attached to the end +of the crankshaft, and the other to the crank case. Another interesting +type is the Burlat rotary, in which both the cylinders and crankshaft +rotate in the same direction, the rotation of the crankshaft being twice +that of the cylinders as regards speed. This engine is arranged to +work on the four-stroke cycle with the crankshaft making four, and the +cylinders two, revolutions per cycle. + +It would appear that the rotary type of engine is capable of but little +more improvement--save for such devices as these of the last two engines +mentioned, there is little that Laurent Seguin has not already done in +the Gnome type. The limitation of the rotary lies in its high fuel and +lubricating oil consumption, which renders it unsuited for long-distance +aero work; it was, in the war period, an admirable engine for such +short runs as might be involved in patrol work 'over the lines,' and +for similar purposes, but the watercooled Vee or even vertical, with +its much lower fuel consumption, was and is to be preferred for distance +work. The rotary air-cooled type has its uses, and for them it will +probably remain among the range of current types for some time to come. +Experience of matters aeronautical is sufficient to show, however, that +prophecy in any direction is most unsafe. + + + + +V. THE HORIZONTALLY-OPPOSED ENGINE + +Among the first internal combustion engines to be taken into use with +aircraft were those of the horizontally-opposed four-stroke cycle type, +and, in every case in which these engines were used, their excellent +balance and extremely even torque rendered them ideal-until the +tremendous increase in power requirements rendered the type too long and +bulky for placing in the fuselage of an aeroplane. As power increased, +there came a tendency toward placing cylinders radially round a central +crankshaft, and, as in the case of the early Anzani, it may be said that +the radial engine grew out of the horizontal opposed piston type. There +were, in 1910--that is, in the early days of small power units, +ten different sizes of the horizontally opposed engine listed for +manufacture, but increase in power requirements practically ruled out +the type for air work. + +The Darracq firm were the leading makers of these engines in 1910; their +smallest size was a 24 horsepower engine, with two cylinders each of 5.1 +inches bore by 4.7 inches stroke. This engine developed its rated power +at 1,500 revolutions per minute, and worked out at a weight of 5 lbs. +per horse-power. With these engines the cranks are so placed that two +regular impulses are given to the crankshaft for each cycle of working, +an arrangement which permits of very even balancing of the inertia +forces of the engine. The Darracq firm also made a four-cylindered +horizontal opposed piston engine, in which two revolutions were given to +the crankshaft per revolution, at equal angular intervals. + +The Dutheil-Chambers was another engine of this type, and had +the distinction of being the second largest constructed. At 1,000 +revolutions per minute it developed 97 horse-power; its four cylinders +were each of 4.93 inches bore by 11.8 inches stroke--an abnormally long +stroke in comparison with the bore. The weight--which owing to the build +of the engine and its length of stroke was bound to be rather high, +actually amounted to 8.2 lbs. per horse-power. Water cooling was +adopted, and the engine was, like the Darracq four-cylinder type, +so arranged as to give two impulses per revolution at equal angular +intervals of crankshaft rotation. + +One of the first engines of this type to be constructed in England was +the Alvaston, a water-cooled model which was made in 20, 30, and 50 +brake horse-power sizes, the largest being a four-cylinder engine. All +three sizes were constructed to run at 1,200 revolutions per minute. In +this make the cylinders were secured to the crank case by means of +four long tie bolts passing through bridge pieces arranged across the +cylinder heads, thus relieving the cylinder walls of all longitudinal +explosion stresses. These bridge pieces were formed from chrome +vanadium steel and milled to an 'H' section, and the bearings for the +valve-tappet were forged solid with them. Special attention was given +to the machining of the interiors of the cylinders and the combustion +heads, with the result that the exceptionally high compression of 95 +lbs. per square inch was obtained, giving a very flexible engine. The +cylinder heads were completely water-jacketed, and copper water-jackets +were also fitted round the cylinders. The mechanically operated valves +were actuated by specially shaped cams, and were so arranged that only +two cams were required for the set of eight valves. The inlet valves at +both ends of the engine were connected by a single feed-pipe to which +the carburettor was attached, the induction piping being arranged above +the engine in an easily accessible position. Auxiliary air ports were +provided in the cylinder walls so that the pistons overran them at the +end of their stroke. A single vertical shaft running in ball-bearings +operated the valves and water circulating pump, being driven by spiral +gearing from the crankshaft at half speed. In addition to the excellent +balance obtained with this engine, the makers claimed with justice that +the number of working parts was reduced to an absolute minimum. + +In the two-cylinder Darracq, the steel cylinders were machined from +solid, and auxiliary exhaust ports, overrun by the piston at the inner +end of its stroke, were provided in the cylinder walls, consisting of a +circular row of drilled holes--this arrangement was subsequently adopted +on some of the Darracq racing car engines. The water jackets were of +copper, soldered to the cylinder walls; both the inlet and exhaust +valves were located in the cylinder heads, being operated by rockers and +push-rods actuated by cams on the halftime shaft driven from one end +of the crankshaft. Ignition was by means of a high-tension magneto, +and long induction pipes connected the-ends of the cylinders to the +carburettor, the latter being placed underneath the engine. Lubrication +was effected by spraying oil into the crank case by means of a pump, and +a second pump circulated the cooling water. + +Another good example of this type of engine was the Eole, which had +eight opposed pistons, each pair of which was actuated by a common +combustion chamber at the centre of the engine, two crankshafts being +placed at the outer ends of the engine. This reversal of the ordinary +arrangement had two advantages; it simplified induction, and further +obviated the need for cylinder heads, since the explosion drove at two +piston heads instead of at one piston head and the top of the cylinder; +against this, however, the engine had to be constructed strongly enough +to withstand the longitudinal stresses due to the explosions, as the +cranks are placed on the outer ends and the cylinders and crank-cases +take the full force of each explosion. Each crankshaft drove a separate +air-screw. + +This pattern of engine was taken up by the Dutheil-Chambers firm in +the pioneer days of aircraft, when the firm in question produced seven +different sizes of horizontal engines. The Demoiselle monoplane used +by Santos-Dumont in 1909 was fitted with a two-cylinder, +horizontally-opposed Dutheil-Chambers engine, which developed 25 brake +horse-power at a speed of 1,100 revolutions per minute, the cylinders +being of 5 inches bore by 5.1 inches stroke, and the total weight of the +engine being some 120 lbs. The crankshafts of these engines were usually +fitted with steel flywheels in order to give a very even torque, +the wheels being specially constructed with wire spokes. In all the +Dutheil-Chambers engines water cooling was adopted, and the cylinders +were attached to the crank cases by means of long bolts passing through +the combustion heads. + +For their earliest machines, the Clement-Bayard firm constructed +horizontal engines of the opposed piston type. The best known of these +was the 30 horse-power size, which had cylinders of 4.7 inches diameter +by 5.1 inches stroke, and gave its rated power at 1,200 revolutions per +minute. In this engine the steel cylinders were secured to the crank +case by flanges, and radiating ribs were formed around the barrel +to assist the air-cooling. Inlet and exhaust valves were actuated by +push-rods and rockers actuated from the second motion shaft mounted +above the crank case; this shaft also drove the high-tension magneto +with which the engine was fitted. A ring of holes drilled round each +cylinder constituted auxiliary ports which the piston uncovered at the +inner end of its stroke, and these were of considerable assistance not +only in expelling exhaust gases, but also in moderating the temperature +of the cylinder and of the main exhaust valve fitted in the cylinder +head. A water-cooled Clement-Bayard horizontal engine was also made, and +in this the auxiliary exhaust ports were not embodied; except in this +particular, the engine was very similar to the water-cooled Darracq. + +The American Ashmusen horizontal engine, developing 100 horse-power, is +probably the largest example of this type constructed. It was made with +six cylinders arranged on each side of a common crank case, with long +bolts passing through the cylinder heads to assist in holding them down. +The induction piping and valve-operating gear were arranged below the +engine, and the half-speed shaft carried the air-screw. + +Messrs Palons and Beuse, Germans, constructed a light-weight, +air-cooled, horizontally-opposed engine, two-cylindered. In this the +cast-iron cylinders were made very thin, and were secured to the +crank case by bolts passing through lugs cast on the outer ends of +the cylinders; the crankshaft was made hollow, and holes were drilled +through the webs of the connecting-rods in order to reduce the weight. +The valves were fitted to the cylinder heads, the inlet valves being of +the automatic type, while the exhaust valves were mechanically operated +from the cam-shaft by means of rockers and push-rods. Two carburettors +were fitted, to reduce the induction piping to a minimum; one was +attached to each combustion chamber, and ignition was by the normal +high-tension magneto driven from the halftime shaft. + +There was also a Nieuport two-cylinder air-cooled horizontal engine, +developing 35 horse-power when running at 1,300 revolutions per minute, +and being built at a weight of 5.1 lbs. per horse-power. The cylinders +were of 5.3 inches diameter by 5.9 inches stroke; the engine followed +the lines of the Darracq and Dutheil-Chambers pretty closely, and thus +calls for no special description. + +The French Kolb-Danvin engine of the horizontal type, first constructed +in 1905, was probably the first two-stroke cycle engine designed to +be applied to the propulsion of aircraft; it never got beyond the +experimental stage, although its trials gave very good results. Stepped +pistons were adopted, and the charging pump at one end was used to +scavenge the power cylinder at the other ends of the engine, the +transfer ports being formed in the main casting. The openings of these +ports were controlled at both ends by the pistons, and the location of +the ports appears to have made it necessary to take the exhaust from the +bottom of one cylinder and from the top of the other. The carburetted +mixture was drawn into the scavenging cylinders, and the usual +deflectors were cast on the piston heads to assist in the scavenging and +to prevent the fresh gas from passing out of the exhaust ports. + + + + +VI. THE TWO-STROKE CYCLE ENGINE + +Although it has been little used for aircraft propulsion, the +possibilities of the two-stroke cycle engine render some study of +it desirable in this brief review of the various types of internal +combustion engine applicable both to aeroplanes and airships. +Theoretically the two-stroke cycle engine--or as it is more commonly +termed, the 'two-stroke,' is the ideal power producer; the doubling of +impulses per revolution of the crankshaft should render it of very much +more even torque than the four-stroke cycle types, while, theoretically, +there should be a considerable saving of fuel, owing to the doubling of +the number of power strokes per total of piston strokes. In practice, +however, the inefficient scavenging of virtually every two-stroke cycle +engine produced nullifies or more than nullifies its advantages over the +four-stroke cycle engine; in many types, too, there is a waste of fuel +gases through the exhaust ports, and much has yet to be done in the way +of experiment and resulting design before the two-stroke cycle engine +can be regarded as equally reliable, economical, and powerful with its +elder brother. + +The first commercially successful engine operating on the two-stroke +cycle was invented by Mr Dugald Clerk, who in 1881 proved the design +feasible. As is more or less generally understood, the exhaust gases of +this engine are discharged from the cylinder during the time that +the piston is passing the inner dead centre, and the compression, +combustion, and expansion of the charge take place in similar manner +to that of the four-stroke cycle engine. The exhaust period is usually +controlled by the piston overrunning ports in the cylinder at the end +of its working stroke, these ports communicating direct with the outer +air--the complication of an exhaust valve is thus obviated; immediately +after the escape of the exhaust gases, charging of the cylinder occurs, +and the fresh gas may be introduced either through a valve in the +cylinder head or through ports situated diametrically opposite to the +exhaust ports. The continuation of the outward stroke of the piston, +after the exhaust ports have been closed, compresses the charge into +the combustion chamber of the cylinder, and the ignition of the mixture +produces a recurrence of the working stroke. + +Thus, theoretically, is obtained the maximum of energy with the minimum +of expenditure; in practice, however, the scavenging of the power +cylinder, a matter of great importance in all internal combustion +engines, is often imperfect, owing to the opening of the exhaust ports +being of relatively short duration; clearing the exhaust gases out of +the cylinder is not fully accomplished, and these gases mix with the +fresh charge and detract from its efficiency. Similarly, owing to the +shorter space of time allowed, the charging of the cylinder with the +fresh mixture is not so efficient as in the four-stroke cycle type; the +fresh charge is usually compressed slightly in a separate chamber--crank +case, independent cylinder, or charging pump, and is delivered to +the working cylinder during the beginning of the return stroke of the +piston, while in engines working on the four-stroke cycle principle a +complete stroke is devoted to the expulsion of the waste gases of the +exhaust, and another full stroke to recharging the cylinder with fresh +explosive mixture. + +Theoretically the two-stroke and the four-stroke cycle engines possess +exactly the same thermal efficiency, but actually this is modified by a +series of practical conditions which to some extent tend to neutralise +the very strong case in favour of the two-stroke cycle engine. The +specific capacity of the engine operating on the two-stroke principle is +theoretically twice that of one operating on the four-stroke cycle, and +consequently, for equal power, the former should require only about half +the cylinder volume of the latter; and, owing to the greater superficial +area of the smaller cylinder, relatively, the latter should be far more +easily cooled than the larger four-stroke cycle cylinder; thus it should +be possible to get higher compression pressures, which in turn should +result in great economy of working. Also the obtaining of a working +impulse in the cylinder for each revolution of the crankshaft should +give a great advantage in regularity of rotation--which it undoubtedly +does--and the elimination of the operating gear for the valves, inlet +and exhaust, should give greater simplicity of design. + +In spite of all these theoretical--and some practical--advantages the +four-stroke cycle engine was universally adopted for aircraft work; +owing to the practical equality of the two principles of operation, so +far as thermal efficiency and friction losses are concerned, there is no +doubt that the simplicity of design (in theory) and high power output +to weight ratio (also in theory) ought to have given the 'two-stroke' +a place on the aeroplane. But this engine has to be developed so as to +overcome its inherent drawbacks; better scavenging methods have yet to +be devised--for this is the principal drawback--before the two-stroke +can come to its own as a prime mover for aircraft. + +Mr Dugald Clerk's original two-stroke cycle engine is indicated roughly, +as regards principle, by the accompanying diagram, from which it will +be seen that the elimination of the ordinary inlet and exhaust valves +of the four-stroke type is more than compensated by a separate cylinder +which, having a piston worked from the connecting-rod of the power +cylinder, was used to charging, drawing the mixture from the carburettor +past the valve in the top of the charging cylinder, and then forcing it +through the connecting pipe into the power cylinder. The inlet valves +both on the charging and the power cylinders are automatic; when the +power piston is near the bottom of its stroke the piston in the charging +cylinder is compressing the carburetted air, so that as soon as the +pressure within the power cylinder is relieved by the exit of the burnt +gases through the exhaust ports the pressure in the charging cylinder +causes the valve in the head of the power cylinder to open, and fresh +mixture flows into the cylinder, replacing the exhaust gases. After +the piston has again covered the exhaust ports the mixture begins to be +compressed, thus automatically closing the inlet valve. Ignition +occurs near the end of the compression stroke, and the working stroke +immediately follows, thus giving an impulse to the crankshaft on every +down stroke of the piston. If the scavenging of the cylinder were +complete, and the cylinder were to receive a full charge of fresh +mixture for every stroke, the same mean effective pressure as is +obtained with four-stroke cycle engines ought to be realised, and at +an equal speed of rotation this engine should give twice the power +obtainable from a four-stroke cycle engine of equal dimensions. This +result was not achieved, and, with the improvements in construction +brought about by experiment up to 1912, the output was found to be only +about fifty per cent more than that of a four-stroke cycle engine of the +same size, so that, when the charging cylinder is included, this engine +has a greater weight per horse-power, while the lowest rate of fuel +consumption recorded was 0.68 lb. per horse-power per hour. + +In 1891 Mr Day invented a two-stroke cycle engine which used the crank +case as a scavenging chamber, and a very large number of these engines +have been built for industrial purposes. The charge of carburetted air +is drawn through a non-return valve into the crank chamber during the +upstroke of the piston, and compressed to about 4 lbs. pressure per +square inch on the down stroke. When the piston approaches the bottom +end of its stroke the upper edge first overruns an exhaust port, and +almost immediately after uncovers an inlet port on the opposite side of +the cylinder and in communication with the crank chamber; the entering +charge, being under pressure, assists in expelling the exhaust gases +from the cylinder. On the next upstroke the charge is compressed into +the combustion space of the cylinder, a further charge simultaneously +entering the crank case to be compressed after the ignition for the +working stroke. To prevent the incoming charge escaping through the +exhaust ports of the cylinder a deflector is formed on the top of the +piston, causing the fresh gas to travel in an upward direction, thus +avoiding as far as possible escape of the mixture to the atmosphere. +From experiments conducted in 1910 by Professor Watson and Mr Fleming +it was found that the proportion of fresh gases which escaped unburnt +through the exhaust ports diminished with increase of speed; at 600 +revolutions per minute about 36 per cent of the fresh charge was lost; +at 1,200 revolutions per minute this was reduced to 20 per cent, and at +1,500 revolutions it was still farther reduced to 6 per cent. + +So much for the early designs. With regard to engines of this type +specially constructed for use with aircraft, three designs call for +special mention. Messrs A. Gobe and H. Diard, Parisian engineers, +produced an eight-cylindered two-stroke cycle engine of rotary design, +the cylinders being co-axial. Each pair of opposite pistons was secured +together by a rigid connecting rod, connected to a pin on a rotating +crankshaft which was mounted eccentrically to the axis of rotation +of the cylinders. The crankshaft carried a pinion gearing with an +internally toothed wheel on the transmission shaft which carried the +air-screw. The combustible mixture, emanating from a common supply pipe, +was led through conduits to the front ends of the cylinders, in which +the charges were compressed before being transferred to the working +spaces through ports in tubular extensions carried by the pistons. +These extensions had also exhaust ports, registering with ports in the +cylinder which communicated with the outer air, and the extensions slid +over depending cylinder heads attached to the crank case by long studs. +The pump charge was compressed in one end of each cylinder, and the +pump spaces each delivered into their corresponding adjacent combustion +spaces. The charges entered the pump spaces during the suction period +through passages which communicated with a central stationary supply +passage at one end of the crank case, communication being cut off when +the inlet orifice to the passage passed out of register with the port +in the stationary member. The exhaust ports at the outer end of the +combustion space opened just before and closed a little later than the +air ports, and the incoming charge assisted in expelling the exhaust +gases in a manner similar to that of the earlier types of two-stroke +cycle engine; The accompanying rough diagram assists in showing the +working of this engine. + +Exhibited in the Paris Aero Exhibition of 1912, the Laviator two-stroke +cycle engine, six-cylindered, could be operated either as a radial or +as a rotary engine, all its pistons acting on a single crank. Cylinder +dimensions of this engine were 3.94 inches bore by 5.12 inches stroke, +and a power output of 50 horse-power was obtained when working at a rate +of 1,200 revolutions per minute. Used as a radial engine, it developed +65 horse-power at the same rate of revolution, and, as the total weight +was about 198 lbs., the weight of about 3 lbs. per horse-power was +attained in radial use. Stepped pistons were employed, the annular space +between the smaller or power piston and the walls of the larger cylinder +being used as a charging pump for the power cylinder situated 120 +degrees in rear of it. The charging cylinders were connected by short +pipes to ports in the crank case which communicated with the hollow +crankshaft through which the fresh gas was supplied, and once in each +revolution each port in the case registered with the port in the +hollow shaft. The mixture which then entered the charging cylinder was +transferred to the corresponding working cylinder when the piston of +that cylinder had reached the end of its power stroke, and immediately +before this the exhaust ports diametrically opposite the inlet ports +were uncovered; scavenging was thus assisted in the usual way. The very +desirable feature of being entirely valveless was accomplished with this +engine, which is also noteworthy for exceedingly compact design. + +The Lamplough six-cylinder two-stroke cycle rotary, shown at the Aero +Exhibition at Olympia in 1911, had several innovations, including a +charging pump of rotary blower type. With the six cylinders, six power +impulses at regular intervals were given on each rotation; otherwise, +the cycle of operations was carried out much as in other two-stroke +cycle engines. The pump supplied the mixture under slight pressure to +an inlet port in each cylinder, which was opened at the same time as the +exhaust port, the period of opening being controlled by the piston. The +rotary blower sucked the mixture from the carburettor and delivered it +to a passage communicating with the inlet ports in the cylinder walls. +A mechanically-operated exhaust valve was placed in the centre of each +cylinder head, and towards the end of the working stroke this valve +opened, allowing part of the burnt gases to escape to the atmosphere; +the remainder was pushed out by the fresh mixture going in through the +ports at the bottom end of the cylinder. In practice, one or other of +the cylinders was always taking fresh mixture while working, therefore +the delivery from the pump was continuous and the mixture had not to be +stored under pressure. + +The piston of this engine was long enough to keep the ports covered +when it was at the top of the stroke, and a bottom ring was provided +to prevent the mixture from entering the crank case. In addition to +preventing leakage, this ring no doubt prevented an excess of oil +working up the piston into the cylinder. As the cylinder fired with +every revolution, the valve gear was of the simplest construction, a +fixed cam lifting each valve as the cylinder came into position. The +spring of the exhaust valve was not placed round the stem in the usual +way, but at the end of a short lever, away from the heat of the exhaust +gases. The cylinders were of cast steel, the crank case of aluminium, +and ball-bearings were fitted to the crankshaft, crank pins, and the +rotary blower pump. Ignition was by means of a high-tension magneto of +the two-spark pattern, and with a total weight of 300 lbs. the maximum +output was 102 brake horse-power, giving a weight of just under 3 lbs. +per horse-power. + +One of the most successful of the two-stroke cycle engines was that +designed by Mr G. F. Mort and constructed by the New Engine Company. +With four cylinders of 3.69 inches bore by 4.5 inches stroke, and +running at 1,250 revolutions per minute, this engine developed 50 brake +horse-power; the total weight of the engine was 155 lbs., thus giving a +weight of 3.1 lbs. per horse-power. A scavenging pump of the rotary type +was employed, driven by means of gearing from the engine crankshaft, and +in order to reduce weight to a minimum the vanes were of aluminium. This +engine was tried on a biplane, and gave very satisfactory results. + +American design yields two apparently successful two-stroke cycle aero +engines. A rotary called the Fredericson engine was said to give an +output of 70 brake horse-power with five cylinders 4.5 inches diameter +by 4.75 inches stroke, running at 1,000 revolutions per minute. Another, +the Roberts two-stroke cycle engine, yielded 100 brake horse-power +from six cylinders of the stepped piston design; two carburettors, each +supplying three cylinders, were fitted to this engine. Ignition was +by means of the usual high-tension magneto, gear-driven from the +crankshaft, and the engine, which was water-cooled, was of compact +design. + +It may thus be seen that the two-stroke cycle type got as far as actual +experiment in air work, and that with considerable success. So far, +however, the greater reliability of the four-stroke cycle has rendered +it practically the only aircraft engine, and the two-stroke has yet some +way to travel before it becomes a formidable competitor, in spite of its +admitted theoretical and questioned practical advantages. + + + + +VII. ENGINES OF THE WAR PERIOD + +The principal engines of British, French, and American design used in +the war period and since are briefly described under the four distinct +types of aero engine; such notable examples as the Rolls-Royce, +Sunbeam, and Napier engines have been given special mention, as they +embodied--and still embody--all that is best in aero engine practice. So +far, however, little has been said about the development of German aero +engine design, apart from the early Daimler and other pioneer makes. + +At the outbreak of hostilities in 1914, thanks to subsidies to +contractors and prizes to aircraft pilots, the German aeroplane +industry was in a comparatively flourishing condition. There were about +twenty-two establishments making different types of heavier-than-air +machines, monoplane and biplane, engined for the most part with the +four-cylinder Argus or the six-cylinder Mercedes vertical type engines, +each of these being of 100 horse-power--it was not till war brought +increasing demands on aircraft that the limit of power began to rise. +Contemporary with the Argus and Mercedes were the Austro-Daimler, +Benz, and N.A.G., in vertical design, while as far as rotary types were +concerned there were two, the Oberursel and the Stahlhertz; of these the +former was by far the most promising, and it came to virtual monopoly +of the rotary-engined plane as soon as the war demand began. It was +practically a copy of the famous Gnome rotary, and thus deserves little +description. + +Germany, from the outbreak of war, practically, concentrated on the +development of the Mercedes engine; and it is noteworthy that, with one +exception, increase of power corresponding with the increased demand +for power was attained without increasing the number of cylinders. The +various models ranged between 75 and 260 horse-power, the latter being +the most recent production of this type. The exception to the rule +was the eight-cylinder 240 horse-power, which was replaced by the 260 +horse-power six-cylinder model, the latter being more reliable and but +very slightly heavier. Of the other engines, the 120 horsepower Argus +and the 160 and 225 horse-power Benz were the most used, the Oberursel +being very largely discarded after the Fokker monoplane had had its day, +and the N.A.G. and Austro-Daimler Daimler also falling to comparative +disuse. It may be said that the development of the Mercedes engine +contributed very largely to such success as was achieved in the war +period by German aircraft, and, in developing the engine, the builders +were careful to make alterations in such a way as to effect the least +possible change in the design of aeroplane to which they were to be +fitted. Thus the engine base of the 175 horse-power model coincided +precisely with that of the 150 horse-power model, and the 200 and 240 +horse-power models retained the same base dimensions. It was estimated, +in 1918, that well over eighty per cent of German aircraft was engined +with the Mercedes type. + +In design and construction, there was nothing abnormal about the +Mercedes engine, the keynote throughout being extreme reliability and +such simplification of design as would permit of mass production in +different factories. Even before the war, the long list of records set +up by this engine formed practical application of the wisdom of this +policy; Bohn's flight of 24 hours 10 minutes, accomplished on July 10th +and 11th, 1914, 9is an instance of this--the flight was accomplished on +an Albatross biplane with a 75 horsepower Mercedes engine. The radial +type, instanced in other countries by the Salmson and Anzani makes, was +not developed in Germany; two radial engines were made in that country +before the war, but the Germans seemed to lose faith in the type under +war conditions, or it may have been that insistence on standardisation +ruled out all but the proved examples of engine. + +Details of one of the middle sizes of Mercedes motor, the 176 +horse-power type, apply very generally to the whole range; this size was +in use up to and beyond the conclusion of hostilities, and it may still +be regarded as characteristic of modern (1920) German practice. The +engine is of the fixed vertical type, has six cylinders in line, not +off-set, and is water-cooled. The cam shaft is carried in a special +bronze casing, seated on the immediate top of the cylinders, and a +vertical shaft is interposed between crankshaft and camshaft, the latter +being driven by bevel gearing. + +On this vertical connecting-shaft the water pump is located, serving to +steady the motion of the shaft. Extending immediately below the camshaft +is another vertical shaft, driven by bevel gears from the crank-shaft, +and terminating in a worm which drives the multiple piston oil pumps. + +The cylinders are made from steel forgings, as are the valve chamber +elbows, which are machined all over and welded together. A jacket of +light steel is welded over the valve elbows and attached to a flange +on the cylinders, forming a water-cooling space with a section of about +7/16 of an inch. The cylinder bore is 5.5 inches, and the stroke 6.29 +inches. The cylinders are attached to the crank case by means of dogs +and long through bolts, which have shoulders near their lower ends and +are bolted to the lower half of the crank chamber. A very light and +rigid structure is thus obtained, and the method of construction won the +flattery of imitation by makers of other nationality. + +The cooling system for the cylinders is extremely efficient. After +leaving the water pump, the water enters the top of the front cylinders +and passes successively through each of the six cylinders of the row; +short tubes, welded to the tops of the cylinders, serve as connecting +links in the system. The Panhard car engines for years were fitted with +a similar cooling system, and the White and Poppe lorry engines were +also similarly fitted; the system gives excellent cooling effect where +it is most needed, round the valve chambers and the cylinder heads. + +The pistons are built up from two pieces; a dropped forged steel piston +head, from which depend the piston pin bosses, is combined with a +cast-iron skirt, into which the steel head is screwed. Four rings are +fitted, three at the upper and one at the lower end of the piston skirt, +and two lubricating oil grooves are cut in the skirt, in addition to the +ring grooves. Two small rivets retain the steel head on the piston skirt +after it has been screwed into position, and it is also welded at two +points. The coefficient of friction between the cast-iron and steel is +considerably less than that which would exist between two steel parts, +and there is less tendency for the skirt to score the cylinder walls +than would be the case if all steel were used--so noticeable is this +that many makers, after giving steel pistons a trial, discarded them in +favour of cast-iron; the Gnome is an example of this, being originally +fitted with a steel piston carrying a brass ring, discarded in favour of +a cast-iron piston with a percentage of steel in the metal mixture. In +the Le Rhone engine the difficulty is overcome by a cast-iron liner to +the cylinders. + +The piston pin of the Mercedes is of chrome nickel steel, and is +retained in the piston by means of a set screw and cotter pin. The +connecting rods, of I section, are very short and rigid, carrying +floating bronze bushes which fit the piston pins at the small end, and +carrying an oil tube on each for conveying oil from the crank pin to the +piston pin. + +The crankshaft is of chrome nickel steel, carried on seven bearings. +Holes are drilled through each of the crank pins and main bearings, for +half the diameter of the shaft, and these are plugged with pressed brass +studs. Small holes, drilled through the crank cheeks, serve to convey +lubricant from the main bearings to the crank pins. The propeller thrust +is taken by a simple ball thrust bearing at the propeller end of the +crankshaft, this thrust bearing being seated in a steel retainer which +is clamped between the two halves of the crank case. At the forward end +of the crankshaft there is mounted a master bevel gear on six splines; +this bevel floats on the splines against a ball thrust bearing, and, +in turn, the thrust is taken by the crank case cover. A stuffing +box prevents the loss of lubricant out of the front end of the crank +chamber, and an oil thrower ring serves a similar purpose at the +propeller end of the crank chamber. + +With a motor speed of 1,450 r.p.m., the vertical shaft at the forward +end of the motor turns at 2,175 r.p.m., this being the speed of the two +magnetos and the water pump. The lower vertical shaft bevel gear and the +magneto driving gear are made integral with the vertical driving shaft, +which is carried in plain bearings in an aluminium housing. This housing +is clamped to the upper half of the crank case by means of three studs. +The cam-shaft carries eighteen cams, these being the inlet and exhaust +cams, and a set of half compression cams which are formed with the +exhaust cams and are put into action when required by means of a lever +at the forward end of the cam-shaft. The cam-shaft is hollow, and +serves as a channel for the conveyance of lubricating oil to each of +the camshaft bearings. At the forward end of this shaft there is also +mounted an air pump for maintaining pressure on the fuel supply tank, +and a bevel gear tachometer drive. + +Lubrication of the engine is carried out by a full pressure system. +The oil is pumped through a single manifold, with seven branches to the +crankshaft main bearings, and then in turn through the hollow crankshaft +to the connecting-rod big ends and thence through small tubes, already +noted, to the small end bearings. The oil pump has four pistons and two +double valves driven from a single eccentric shaft on which are mounted +four eccentrics. The pump is continuously submerged in oil; in order to +avoid great variations in pressure in the oil lines there is a piston +operated pressure regulator, cut in between the pump and the oil lines. +The two small pistons of the pump take fresh oil from a tank located in +the fuselage of the machine; one of these delivers oil to the cam shaft, +and one delivers to the crankshaft; this fresh oil mixes with the used +oil, returns to the base, and back to the main large oil pump cylinders. +By means of these small pump pistons a constant quantity of oil is kept +in the motor, and the oil is continually being freshened by means of the +new oil coming in. All the oil pipes are very securely fastened to the +lower half of the crank case, and some cooling of the oil is effected +by air passing through channels cast in the crank case on its way to the +carburettor. + +A light steel manifold serves to connect the exhaust ports of the +cylinders to the main exhaust pipe, which is inclined about 25 degrees +from vertical and is arranged to give on to the atmosphere just over the +top of the upper wing of the aeroplane. + +As regards carburation, an automatic air valve surrounds the throat of +the carburettor, maintaining normal composition of mixture. A small jet +is fitted for starting and running without load. The channels cast in +the crank chamber, already alluded to in connection with oil-cooling, +serve to warm the air before it reaches the carburettor, of which the +body is water-jacketed. + +Ignition of the engine is by means of two Bosch ZH6 magnetos, driven at +a speed of 2,175 revolutions per minute when the engine is running at +its normal speed of 1,450 revolutions. The maximum advance of spark is +12 mm., or 32 degrees before the top dead centre, and the firing order +of the cylinders is 1,5,3,6,2,4. + +The radiator fitted to this engine, together with the water-jackets, +has a capacity of 25 litres of water, it is rectangular in shape, and is +normally tilted at an angle of 30 degrees from vertical. Its weight is +26 kg., and it offers but slight head resistance in flight. + +The radial type of engine, neglected altogether in Germany, was brought +to a very high state of perfection at the end of the War period by +British makers. Two makes, the Cosmos Engineering Company's 'Jupiter' +and 'Lucifer,' and the A.B.C. 'Wasp II' and 'Dragon Fly 1A' require +special mention for their light weight and reliability on trials. + +The Cosmos 'Jupiter' was--for it is no longer being made--a 450 +horse-power nine-cylinder radial engine, air-cooled, with the cylinders +set in one single row; it was made both geared to reduce the propeller +revolutions relatively to the crankshaft revolutions, and ungeared; +the normal power of the geared type was 450 horse-power, and the total +weight of the engine, including carburettors, magnetos, etc., was only +757 lbs.; the engine speed was 1,850 revolutions per minute, and the +propeller revolutions were reduced by the gearing to 1,200. Fitted to a +'Bristol Badger' aeroplane, the total weight was 2,800 lbs., including +pilot, passenger, two machine-guns, and full military load; at 7,000 +feet the registered speed, with corrections for density, was 137 miles +per hour; in climbing, the first 2,000 feet was accomplished in 1 minute +4 seconds; 4,000 feet was reached in 2 minutes 10 seconds; 6,000 feet +was reached in 3 minutes 33 seconds, and 7,000 feet in 4 minutes 15 +seconds. It was intended to modify the plane design and fit a new +propeller, in order to attain even better results, but, if trials were +made with these modifications, the results are not obtainable. + +The Cosmos 'Lucifer' was a three-cylinder radial type engine of 100 +horse-power, inverted Y design, made on the simplest possible principles +with a view to quantity production and extreme reliability. The rated +100 horse-power was attained at 1,600 revolutions per minute, and the +cylinder dimensions were 5.75 bore by 6.25 inches stroke. The cylinders +were of aluminium and steel mixture, with aluminium heads; overhead +valves, operated by push rods on the front side of the cylinders, were +fitted, and a simple reducing gear ran them at half engine speed. The +crank case was a circular aluminium casting, the engine being attached +to the fuselage of the aeroplane by a circular flange situated at the +back of the case; propeller shaft and crankshaft were integral. Dual +ignition was provided, the generator and distributors being driven off +the back end of the engine and the distributors being easily accessible. +Lubrication was by means of two pumps, one scavenging and one suction, +oil being fed under pressure from the crankshaft. A single carburettor +fed all three cylinders, the branch pipe from the carburettor to the +circular ring being provided with an exhaust heater. The total weight of +the engine, 'all on,' was 280 lbs. + +The A.B.C. 'Wasp II,' made by Walton Motors, Limited, is a +seven-cylinder radial, air-cooled engine, the cylinders having a bore +of 4.75 inches and stroke 6.25 inches. The normal brake horse-power +at 1,650 revolutions is 160, and the maximum 200 at a speed of 1,850 +revolutions per minute. Lubrication is by means of two rotary pumps, +one feeding through the hollow crankshaft to the crank pin, giving +centrifugal feed to big end and thence splash oiling, and one feeding to +the nose of the engine, dropping on to the cams and forming a permanent +sump for the gears on the bottom of the engine nose. Two carburettors +are fitted, and two two-spark magnetos, running at one and +three-quarters engine speed. The total weight of this engine is 350 +lbs., or 1.75 lbs. per horse-power. Oil consumption at 1,850 revolutions +is.03 pints per horse-power per hour, and petrol consumption is.56 pints +per horsepower per hour. The engine thus shows as very economical in +consumption, as well as very light in weight. + +The A.B.C. 'Dragon Fly 1A 'is a nine-cylinder radial engine having +one overhead inlet and two overhead exhaust valves per cylinder. The +cylinder dimensions are 5.5 inches bore by 6.5 inches stroke, and +the normal rate of speed, 1,650 revolutions per minute, gives 340 +horse-power. The oiling is by means of two pumps, the system being +practically identical with that of the 'Wasp II.' Oil consumption +is.021 pints per brake horse-power per hour, and petrol consumption.56 +pints--the same as that of the 'Wasp II.' The weight of the complete +engine, including propeller boss, is 600 lbs., or 1,765 lbs. per +horse-power. + +These A.B.C. radials have proved highly satisfactory on tests, and their +extreme simplicity of design and reliability commend them as engineering +products and at the same time demonstrate the value, for aero work, of +the air-cooled radial design--when this latter is accompanied by sound +workmanship. These and the Cosmos engines represent the minimum of +weight per horse-power yet attained, together with a practicable degree +of reliability, in radial and probably any aero engine design. + + + + +APPENDIX A + +GENERAL MENSIER'S REPORT ON THE TRIALS OF CLEMENT ADER'S AVION. + + Paris, October 21, 1897. + +Report on the trials of M. Clement Ader's aviation apparatus. + +M. Ader having notified the Minister of War by letter, July 21, 1897, +that the Apparatus of Aviation which he had agreed to build under the +conditions set forth in the convention of July 24th, 1894, was ready, +and therefore requesting that trials be undertaken before a Committee +appointed for this purpose as per the decision of August 4th, the +Committee was appointed as follows:-- + +Division General Mensier, Chairman; Division General Delambre, Inspector +General of the Permanent Works of Coast Defence, Member of the Technical +Committee of the Engineering Corps; Colonel Laussedat, Director of the +Conservatoire des Arts et Metiers; Sarrau, Member of the Institute, +Professor of Mechanical Engineering at the Polytechnic School; Leaute, +Member of the Institute, Professor of Mechanical Engineering at the +Polytechnique School. + +Colonel Laussedat gave notice at once that his health and work as +Director of the Conservatoire des Arts et Metiers did not permit him +to be a member of the Committee; the Minister therefore accepted his +resignation on September 24th, and decided not to replace him. + +Later on, however, on the request of the Chairman of the Committee, the +Minister appointed a new member General Grillon, commanding the Engineer +Corps of the Military Government of Paris. + +To carry on the trials which were to take place at the camp of Satory, +the Minister ordered the Governor of the Military Forces of Paris to +requisition from the Engineer Corps, on the request of the Chairman of +the Committee, the men necessary to prepare the grounds at Satory. + +After an inspection made on the 16th an aerodrome was chosen. M. Ader's +idea was to have it of circular shape with a width of 40 metres and an +average diameter of 450 metres. The preliminary work, laying out the +grounds, interior and exterior circumference, etc., was finished at the +end of August; the work of smoothing off the grounds began September 1st +with forty-five men and two rollers, and was finished on the day of the +first tests, October 12th. + +The first meeting of the Committee was held August 18th in M. Ader's +workshop; the object being to demonstrate the machine to the Committee +and give all the information possible on the tests that were to be held. +After a careful examination and after having heard all the explanations +by the inventor which were deemed useful and necessary, the Committee +decided that the apparatus seemed to be built with a perfect +understanding of the purpose to be fulfilled as far as one could judge +from a study of the apparatus at rest; they therefore authorised M. Ader +to take the machine apart and carry it to the camp at Satory so as to +proceed with the trials. + +By letter of August 19th the Chairman made report to the Minister of the +findings of the Committee. + +The work on the grounds having taken longer than was anticipated, the +Chairman took advantage of this delay to call the Committee together +for a second meeting, during which M. Ader was to run the two propulsive +screws situated at the forward end of the apparatus. + +The meeting was held October 2nd. It gave the Committee an opportunity +to appreciate the motive power in all its details; firebox, boiler, +engine, under perfect control, absolute condensation, automatic fuel +and feed of the liquid to be vaporised, automatic lubrication and +scavenging; everything, in a word, seemed well designed and executed. + +The weights in comparison with the power of the engine realised a +considerable advance over anything made to date, since the two engines +weighed together realised 42 kg., the firebox and boiler 60 kg., the +condenser 15 kg., or a total of 117 kg. for approximately 40 horse-power +or a little less than 3 kg. per horse-power. + +One of the members summed up the general opinion by saying: 'Whatever +may be the result from an aviation point of view, a result which could +not be foreseen for the moment, it was nevertheless proven that from +a mechanical point of view M. Ader's apparatus was of the greatest +interest and real ingeniosity. He expressed a hope that in any case the +machine would not be lost to science.' + +The second experiment in the workshop was made in the presence of the +Chairman, the purpose being to demonstrate that the wings, having a +spread of 17 metres, were sufficiently strong to support the weight of +the apparatus. With this object in view, 14 sliding supports were placed +under each one of these, representing imperfectly the manner in which +the wings would support the machine in the air; by gradually raising the +supports with the slides, the wheels on which the machine rested were +lifted from the ground. It was evident at that time that the members +composing the skeleton of the wings supported the apparatus, and it was +quite evident that when the wings were supported by the air on every +point of their surface, the stress would be better equalised than when +resting on a few supports, and therefore the resistance to breakage +would be considerably greater. + +After this last test, the work on the ground being practically finished, +the machine was transported to Satory, assembled and again made ready +for trial. + +At first M. Ader was to manoeuvre the machine on the ground at a +moderate speed, then increase this until it was possible to judge +whether there was a tendency for the machine to rise; and it was only +after M. Ader had acquired sufficient practice that a meeting of the +Committee was to be called to be present at the first part of the +trials; namely, volutions of the apparatus on the ground. + +The first test took place on Tuesday, October 12th, in the presence +of the Chairman of the Committee. It had rained a good deal during the +night and the clay track would have offered considerable resistance to +the rolling of the machine; furthermore, a moderate wind was blowing +from the south-west, too strong during the early part of the afternoon +to allow of any trials. + +Toward sunset, however, the wind having weakened, M. Ader decided to +make his first trial; the machine was taken out of its hangar, the wings +were mounted and steam raised. M. Ader in his seat had, on each side of +him, one man to the right and one to the left, whose duty was to rectify +the direction of the apparatus in the event that the action of the +rear wheel as a rudder would not be sufficient to hold the machine in a +straight course. + +At 5.25 p.m. the machine was started, at first slowly and then at an +increased speed; after 250 or 300 metres, the two men who were being +dragged by the apparatus were exhausted and forced to fall flat on +the ground in order to allow the wings to pass over them, and the +trip around the track was completed, a total of 1,400 metres, without +incident, at a fair speed, which could be estimated to be from 300 to +400 metres per minute. Notwithstanding M. Ader's inexperience, this +being the first time that he had run his apparatus, he followed +approximately the chalk line which marked the centre of the track and he +stopped at the exact point from which he started. + +The marks of the wheels on the ground, which was rather soft, did not +show up very much, and it was clear that a part of the weight of the +apparatus had been supported by the wings, though the speed was only +about one-third of what the machine could do had M. Ader used all its +motive power; he was running at a pressure of from 3 to 4 atmospheres, +when he could have used 10 to 12. + +This first trial, so fortunately accomplished, was of great importance; +it was the first time that a comparatively heavy vehicle (nearly 400 +kg., including the weight of the operator, fuel, and water) had been set +in motion by a tractive apparatus, using the air solely as a propelling +medium. The favourable report turned in by the Committee after the +meeting of October 2nd was found justified by the results demonstrated +on the grounds, and the first problem of aviation, namely, the creation +of efficient motive power, could be considered as solved, since the +propulsion of the apparatus in the air would be a great deal easier +than the traction on the ground, provided that the second part of the +problem, the sustaining of the machine in the air, would be realised. + +The next day, Wednesday the 13th, no further trials were made on account +of the rain and wind. + +On Thursday the 14th the Chairman requested that General Grillon, who +had just been appointed a member of the Committee, accompany him so as +to have a second witness. + +The weather was fine, but a fairly strong, gusty wind was blowing from +the south. M. Ader explained to the two members of the Committee the +danger of these gusts, since at two points of the circumference the wind +would strike him sideways. The wind was blowing in the direction A B, +the apparatus starting from C, and running in the direction shown by the +arrow. The first dangerous spot would be at B. The apparatus had been +kept in readiness in the event of the wind dying down. Toward sunset the +wind seemed to die down, as it had done on the evening of the 12th. M. +Ader hesitated, which, unfortunately, further events only justified, but +decided to make a new trial. + +At the start, which took place at 5.15 p.m., the apparatus, having +the wind in the rear, seemed to run at a fairly regular speed; it was, +nevertheless, easy to note from the marks of the wheels on the ground +that the rear part of the apparatus had been lifted and that the rear +wheel, being the rudder, had not been in constant contact with the +ground. When the machine came to the neighbourhood of B, the two members +of the Committee saw the machine swerve suddenly out of the track in a +semicircle, lean over to the right and finally stop. They immediately +proceeded to the point where the accident had taken place and +endeavoured to find an explanation for the same. The Chairman finally +decided as follows: + +M. Ader was the victim of a gust of wind which he had feared as he +explained before starting out; feeling himself thrown out of his course, +he tried to use the rudder energetically, but at that time the rear +wheel was not in contact with the ground, and therefore did not +perform its function; the canvas rudder, which had as its purpose the +manoeuvring of the machine in the air, did not have sufficient action +on the ground. It would have been possible without any doubt to react +by using the propellers at unequal speed, but M. Ader, being still +inexperienced, had not thought of this. Furthermore, he was thrown +out of his course so quickly that he decided, in order to avoid a more +serious accident, to stop both engines. This sudden stop produced the +half-circle already described and the fall of the machine on its side. + +The damage to the machine was serious; consisting at first sight of the +rupture of both propellers, the rear left wheel and the bending of the +left wing tip. It will only be possible to determine after the machine +is taken apart whether the engine, and more particularly the organs of +transmission, have been put out of line. + +Whatever the damage may be, though comparatively easy to repair, it will +take a certain amount of time, and taking into consideration the time +of year it is evident that the tests will have to be adjourned for the +present. + +As has been said in the above report, the tests, though prematurely +interrupted, have shown results of great importance, and though the +final results are hard to foresee, it would seem advisable to continue +the trials. By waiting for the return of spring there will be plenty of +time to finish the tests and it will not be necessary to rush matters, +which was a partial cause of the accident. The Chairman of the Committee +personally has but one hope, and that is that a decision be reached +accordingly. + + Division General, + + Chairman of the Committee, + + Mensier. + +Boulogne-sur-Seine, October 21st, 1897. + + + Annex to the Report of October 21st. + +General Grillon, who was present at the trials of the 14th, and who saw +the report relative to what happened during that day, made the following +observations in writing, which are reproduced herewith in quotation +marks. The Chairman of the Committee does not agree with General Grillon +and he answers these observations paragraph by paragraph. + +1. 'If the rear wheel (there is only one of these) left but intermittent +tracks on the ground, does that prove that the machine has a tendency to +rise when running at a certain speed?' + +Answer.--This does not prove anything in any way, and I was very careful +not to mention this in my report, this point being exactly what was +needed and that was not demonstrated during the two tests made on the +grounds. + +'Does not this unequal pressure of the two pair of wheels on the ground +show that the centre of gravity of the apparatus is placed too far +forward and that under the impulse of the propellers the machine has a +tendency to tilt forward, due to the resistance of the air?' + +Answer.--The tendency of the apparatus to rise from the rear when it was +running with the wind seemed to be brought about by the effects of the +wind on the huge wings, having a spread of 17 metres, and I believe that +when the machine would have faced the wind the front wheels would have +been lifted. + +During the trials of October 12th, when a complete circuit of the track +was accomplished without incidents, as I and Lieut. Binet witnessed, +there was practically no wind. I was therefore unable to verify whether +during this circuit the two front wheels or the rear wheel were in +constant contact with the ground, because when the trial was over it was +dark (it was 5.30) and the next day it was impossible to see anything +because it had rained during the night and during Wednesday morning. But +what would prove that the rear wheel was in contact with the ground at +all times is the fact that M. Ader, though inexperienced, did not swerve +from the circular track, which would prove that he steered pretty well +with his rear wheel--this he could not have done if he had been in the +air. + +In the tests of the 12th, the speed was at least as great as on the +14th. + +2. 'It would seem to me that if M. Ader thought that his rear wheels +were off the ground he should have used his canvas rudder in order to +regain his proper course; this was the best way of causing the machine +to rotate, since it would have given an angular motion to the front +axle.' + +Answer.--I state in my report that the canvas rudder whose object was +the manoeuvre of the apparatus in the air could have no effect on the +apparatus on the ground, and to convince oneself of this point it is +only necessary to consider the small surface of this canvas rudder +compared with the mass to be handled on the ground, a weight of +approximately 400 kg. According to my idea, and as I have stated in my +report, M. Ader should have steered by increasing the speed on one of +his propellers and slowing down the other. He admitted afterward that +this remark was well founded, but that he did not have time to think of +it owing to the suddenness of the accident. + +3. 'When the apparatus fell on its side it was under the sole influence +of the wind, since M. Ader had stopped the machine. Have we not a result +here which will always be the same when the machine comes to the ground, +since the engines will always have to be stopped or slowed down when +coming to the ground? Here seems to be a bad defect of the apparatus +under trial.' + +Answer.--I believe that the apparatus fell on its side after coming to +a stop, not on account of the wind, but because the semicircle described +was on rough ground and one of the wheels had collapsed. + + Mensier. + +October 27th, 1897. + + + + +APPENDIX B + +Specification and Claims of Wright Patent, No. 821393. Filed March 23rd, +1903. Issued May 22nd, 1906. Expires May 22nd, 1923. + +To all whom it may concern. + +Be it known that we, Orville Wright and Wilbur Wright, citizens of the +United States, residing in the city of Dayton, county of Montgomery, +and State of Ohio, have invented certain new and useful Improvements in +Flying Machines, of which the following is a specification. + +Our invention relates to that class of flying-machines in which +the weight is sustained by the reactions resulting when one or more +aeroplanes are moved through the air edgewise at a small angle of +incidence, either by the application of mechanical power or by the +utilisation of the force of gravity. + +The objects of our invention are to provide means for maintaining +or restoring the equilibrium or lateral balance of the apparatus, to +provide means for guiding the machine both vertically and horizontally, +and to provide a structure combining lightness, strength, convenience of +construction and certain other advantages which will hereinafter appear. + +To these ends our invention consists in certain novel features, which we +will now proceed to describe and will then particularly point out in the +claims. In the accompanying drawings, Figure I 1 is a perspective view +of an apparatus embodying our invention in one form. Fig. 2 is a plan +view of the same, partly in horizontal section and partly broken away. +Fig. 3 is a side elevation, and Figs. 4 and 5 are detail views, of one +form of flexible joint for connecting the upright standards with the +aeroplanes. + +In flying machines of the character to which this invention relates the +apparatus is supported in the air by reason of the contact between the +air and the under surface of one or more aeroplanes, the contact surface +being presented at a small angle of incidence to the air. The relative +movements of the air and aeroplane may be derived from the motion of +the air in the form of wind blowing in the direction opposite to that in +which the apparatus is travelling or by a combined downward and forward +movement of the machine, as in starting from an elevated position or +by combination of these two things, and in either case the operation is +that of a soaring-machine, while power applied to the machine to propel +it positively forward will cause the air to support the machine in a +similar manner. In either case owing to the varying conditions to be +met there are numerous disturbing forces which tend to shift the machine +from the position which it should occupy to obtain the desired results. +It is the chief object of our invention to provide means for remedying +this difficulty, and we will now proceed to describe the construction by +means of which these results are accomplished. + +In the accompanying drawing we have shown an apparatus embodying our +invention in one form. In this illustrative embodiment the machine is +shown as comprising two parallel superposed aeroplanes, 1 and 2, may be +embodied in a structure having a single aeroplane. Each aeroplane is of +considerably greater width from side to side than from front to rear. +The four corners of the upper aeroplane are indicated by the reference +letters a, b, c, and d, while the corresponding corners of the lower +aeroplane 2 are indicated by the reference letters e, f, g, and h. The +marginal lines ab and ef indicate the front edges of the aeroplanes, the +lateral margins of the upper aeroplane are indicated, respectively, +by the lines ad and bc, the lateral margins of the lower aeroplane are +indicated, respectively, by the lines eh and fg, while the rear margins +of the upper and lower aeroplanes are indicated, respectively, by the +lines cd and gh. + +Before proceeding to a description of the fundamental theory of +operation of the structure we will first describe the preferred mode of +constructing the aeroplanes and those portions of the structure which +serve to connect the two aeroplanes. + +Each aeroplane is formed by stretching cloth or other suitable fabric +over a frame composed of two parallel transverse spars 3, extending +from side to side of the machine, their ends being connected by bows 4 +extending from front to rear of the machine. The front and rear spars +3 of each aeroplane are connected by a series of parallel ribs 5, which +preferably extend somewhat beyond the rear spar, as shown. These spars, +bows, and ribs are preferably constructed of wood having the necessary +strength, combined with lightness and flexibility. Upon this framework +the cloth which forms the supporting surface of the aeroplane is +secured, the frame being enclosed in the cloth. The cloth for each +aeroplane previous to its attachment to its frame is cut on the bias +and made up into a single piece approximately the size and shape of the +aeroplane, having the threads of the fabric arranged diagonally to the +transverse spars and longitudinal ribs, as indicated at 6 in Fig. 2. +Thus the diagonal threads of the cloth form truss systems with the spars +and ribs, the threads constituting the diagonal members. A hem is formed +at the rear edge of the cloth to receive a wire 7, which is connected to +the ends of the rear spar and supported by the rearwardly-extending ends +of the longitudinal ribs 5, thus forming a rearwardly-extending flap +or portion of the aeroplane. This construction of the aeroplane gives +a surface which has very great strength to withstand lateral and +longitudinal strains, at the same time being capable of being bent or +twisted in the manner hereinafter described. + +When two aeroplanes are employed, as in the construction illustrated, +they are connected together by upright standards 8. These standards are +substantially rigid, being preferably constructed of wood and of equal +length, equally spaced along the front and rear edges of the aeroplane, +to which they are connected at their top and bottom ends by hinged +joints or universal joints of any suitable description. We have shown +one form of connection which may be used for this purpose in Figs. 4 and +5 of the drawings. In this construction each end of the standard 8 +has secured to it an eye 9 which engages with a hook 10, secured to a +bracket plate 11, which latter plate is in turn fastened to the spar 3. +Diagonal braces or stay-wires 12 extend from each end of each standard +to the opposite ends of the adjacent standards, and as a convenient mode +of attaching these parts I have shown a hook 13 made integral with the +hook 10 to receive the end of one of the stay-wires, the other stay-wire +being mounted on the hook 10. The hook 13 is shown as bent down to +retain the stay-wire in connection to it, while the hook 10 is shown +as provided with a pin 14 to hold the staywire 12 and eye 9 in position +thereon. It will be seen that this construction forms a truss system +which gives the whole machine great transverse rigidity and strength, +while at the same time the jointed connections of the parts permit the +aeroplanes to be bent or twisted in the manner which we will now proceed +to describe. + +15 indicates a rope or other flexible connection extending lengthwise +of the front of the machine above the lower aeroplane, passing under +pulleys or other suitable guides 16 at the front corners e and f of the +lower aeroplane, and extending thence upward and rearward to the upper +rear corners c and d, of the upper aeroplane, where they are attached, +as indicated at 17. To the central portion of the rope there is +connected a laterally-movable cradle 18, which forms a means for moving +the rope lengthwise in one direction or the other, the cradle being +movable toward either side of the machine. We have devised this cradle +as a convenient means for operating the rope 15, and the machine is +intended to be generally used with the operator lying face downward on +the lower aeroplane, with his head to the front, so that the operator's +body rests on the cradle, and the cradle can be moved laterally by the +movements of the operator's body. It will be understood, however, that +the rope 15 may be manipulated in any suitable manner. + +19 indicates a second rope extending transversely of the machine along +the rear edge of the body portion of the lower aeroplane, passing under +suitable pulleys or guides 20 at the rear corners g and h of the lower +aeroplane and extending thence diagonally upward to the front corners a +and b of the upper aeroplane, where its ends are secured in any suitable +manner, as indicated at 21. + +Considering the structure so far as we have now described it, and +assuming that the cradle 18 be moved to the right in Figs. 1 and 2, +as indicated by the arrows applied to the cradle in Fig. 1 and by the +dotted lines in Fig. 2, it will be seen that that portion of the rope 15 +passing under the guide pulley at the corner e and secured to the corner +d will be under tension, while slack is paid out throughout the other +side or half of the rope 15. The part of the rope 15 under tension +exercises a downward pull upon the rear upper corner d of the structure +and an upward pull upon the front lower corner e, as indicated by the +arrows. This causes the corner d to move downward and the corner e to +move upward. As the corner e moves upward it carries the corner a upward +with it, since the intermediate standard 8 is substantially rigid and +maintains an equal distance between the corners a and e at all times. +Similarly, the standard 8, connecting the corners d and h, causes the +corner h to move downward in unison with the corner d. Since the corner +a thus moves upward and the corner h moves downward, that portion of +the rope 19 connected to the corner a will be pulled upward through the +pulley 20 at the corner h, and the pull thus exerted on the rope 19 will +pull the corner b on the other wise of the machine downward and at the +same time pull the corner g at said other side of the machine upward. +This results in a downward movement of the corner b and an upward +movement of the corner c. Thus it results from a lateral movement of the +cradle 18 to the right in Fig. 1 that the lateral margins ad and eh at +one side of the machine are moved from their normal positions in which +they lie in the normal planes of their respective aeroplanes, into +angular relations with said normal planes, each lateral margin on this +side of the machine being raised above said normal plane at its forward +end and depressed below said normal plane at its rear end, said lateral +margins being thus inclined upward and forward. At the same time a +reverse inclination is imparted to the lateral margins bc end fg at the +other side of the machine, their inclination being downward and forward. +These positions are indicated in dotted lines in Fig. 1 of the drawings. +A movement of the cradle 18 in the opposite direction from its normal +position will reverse the angular inclination of the lateral margins of +the aeroplanes in an obvious manner. By reason of this construction it +will be seen that with the particular mode of construction now under +consideration it is possible to move the forward corner of the lateral +edges of the aeroplane on one side of the machine either above or below +the normal planes of the aeroplanes, a reverse movement of the forward +corners of the lateral margins on the other side of the machine +occurring simultaneously. During this operation each aeroplane is +twisted or distorted around a line extending centrally across the same +from the middle of one lateral margin to the middle of the other lateral +margin, the twist due to the moving of the lateral margins to different +angles extending across each aeroplane from side to side, so that each +aeroplane surface is given a helicoidal warp or twist. We prefer this +construction and mode of operation for the reason that it gives a +gradually increasing angle to the body of each aeroplane from the +centre longitudinal line thereof outward to the margin, thus giving a +continuous surface on each side of the machine, which has a gradually +increasing or decreasing angle of incidence from the centre of the +machine to either side. We wish it to be understood, however, that our +invention is not limited to this particular construction, since any +construction whereby the angular relations of the lateral margins of +the aeroplanes may be varied in opposite directions with respect to +the normal planes of said aeroplanes comes within the scope of our +invention. Furthermore, it should be understood that while the lateral +margins of the aeroplanes move to different angular positions with +respect to or above and below the normal planes of said aeroplanes, +it does not necessarily follow that these movements bring the opposite +lateral edges to different angles respectively above and below a +horizontal plane since the normal planes of the bodies of the aeroplanes +are inclined to the horizontal when the machine is in flight, said +inclination being downward from front to rear, and while the forward +corners on one side of the machine may be depressed below the +normal planes of the bodies of the aeroplanes said depression is not +necessarily sufficient to carry them below the horizontal planes passing +through the rear corners on that side. Moreover, although we prefer to +so construct the apparatus that the movements of the lateral margins +on the opposite sides of the machine are equal in extent and opposite m +direction, yet our invention is not limited to a construction producing +this result, since it may be desirable under certain circumstances +to move the lateral margins on one side of the machine just described +without moving the lateral margins on the other side of the machine to +an equal extent in the opposite direction. Turning now to the purpose of +this provision for moving the lateral margins of the aeroplanes in the +manner described, it should be premised that owing to various conditions +of wind pressure and other causes the body of the machine is apt to +become unbalanced laterally, one side tending to sink and the other side +tending to rise, the machine turning around its central longitudinal +axis. The provision which we have just described enables the operator +to meet this difficulty and preserve the lateral balance of the machine. +Assuming that for some cause that side of the machine which lies to +the left of the observer in Figs. 1 and 2 has shown a tendency to drop +downward, a movement of the cradle 18 to the right of said figures, as +herein before assumed, will move the lateral margins of the aeroplanes +in the manner already described, so that the margins ad and eh will be +inclined downward and rearward, and the lateral margins bc and fg will +be inclined upward and rearward with respect to the normal planes of the +bodies of the aeroplanes. With the parts of the machine in this position +it will be seen that the lateral margins ad and eh present a larger +angle of incidence to the resisting air, while the lateral margins on +the other side of the machine present a smaller angle of incidence. +Owing to this fact, the side of the machine presenting the larger angle +of incidence will tend to lift or move upward, and this upward movement +will restore the lateral balance of the machine. When the other side of +the machine tends to drop, a movement of the cradle 18 in the reverse +direction will restore the machine to its normal lateral equilibrium. Of +course, the same effect will be produced in the same way in the case of +a machine employing only a single aeroplane. + +In connection with the body of the machine as thus operated we employ +a vertical rudder or tail 22, so supported as to turn around a vertical +axis. This rudder is supported at the rear ends on supports or arms 23, +pivoted at their forward ends to the rear margins of the upper and lower +aeroplanes, respectively. These supports are preferably V-shaped, as +shown, so that their forward ends are comparatively widely separated, +their pivots being indicated at 24. Said supports are free to swing +upward at their free rear ends, as indicated in dotted lines in Fig. +3, their downward movement being limited in any suitable manner. The +vertical pivots of the rudder 22 are indicated at 25, and one of these +pivots has mounted thereon a sheave or pulley 26, around which passes a +tiller-rope 27, the ends of which are extended out laterally and secured +to the rope 19 on opposite sides of the central point of said rope. By +reason of this construction the lateral shifting of the cradle 18 serves +to turn the rudder to one side or the other of the line of flight. It +will be observed in this connection that the construction is such that +the rudder will always be so turned as to present its resisting +surface on that side of the machine on which the lateral margins of the +aeroplanes present the least angle of resistance. The reason of this +construction is that when the lateral margins of the aeroplanes are +so turned in the manner hereinbefore described as to present different +angles of incidence to the atmosphere, that side presenting the largest +angle of incidence, although being lifted or moved upward in the manner +already described, at the same time meets with an increased resistance +to its forward motion, while at the same time the other side of the +machine, presenting a smaller angle of incidence, meets with less +resistance to its forward motion and tends to move forward more rapidly +than the retarded side. This gives the machine a tendency to turn around +its vertical axis, and this tendency if not properly met will not only +change the direction of the front of the machine, but will ultimately +permit one side thereof to drop into a position vertically below the +other side with the aero planes in vertical position, thus causing the +machine to fall. The movement of the rudder, hereinbefore described, +prevents this action, since it exerts a retarding influence on that side +of the machine which tends to move forward too rapidly and keeps the +machine with its front properly presented to the direction of flight and +with its body properly balanced around its central longitudinal axis. +The pivoting of the supports 23 so as to permit them to swing upward +prevents injury to the rudder and its supports in case the machine +alights at such an angle as to cause the rudder to strike the ground +first, the parts yielding upward, as indicated in dotted lines in Fig. +3, and thus preventing injury or breakage. We wish it to be understood, +however, that we do not limit ourselves to the particular description of +rudder set forth, the essential being that the rudder shall be vertical +and shall be so moved as to present its resisting surface on that side +of the machine which offers the least resistance to the atmosphere, so +as to counteract the tendency of the machine to turn around a vertical +axis when the two sides thereof offer different resistances to the air. + +From the central portion of the front of the machine struts 28 extend +horizontally forward from the lower aeroplane, and struts 29 extend +downward and forward from the central portion of the upper aeroplane, +their front ends being united to the struts 28, the forward extremities +of which are turned up, as indicated at 30. These struts 28 and 29 form +truss-skids projecting in front of the whole frame of the machine +and serving to prevent the machine from rolling over forward when it +alights. The struts 29 serve to brace the upper portion of the main +frame and resist its tendency to move forward after the lower aeroplane +has been stopped by its contact with the earth, thereby relieving the +rope 19 from undue strain, for it will be understood that when the +machine comes into contact with the earth, further forward movement of +the lower portion thereof being suddenly arrested, the inertia of the +upper portion would tend to cause it to continue to move forward if +not prevented by the struts 29, and this forward movement of the upper +portion would bring a very violent strain upon the rope 19, since it +is fastened to the upper portion at both of its ends, while its lower +portion is connected by the guides 20 to the lower portion. The struts +28 and 29 also serve to support the front or horizontal rudder, the +construction of which we will now proceed to describe. + +The front rudder 31 is a horizontal rudder having a flexible body, the +same consisting of three stiff crosspieces or sticks 32, 33, and 34, and +the flexible ribs 35, connecting said cross-pieces and extending from +front to rear. The frame thus provided is covered by a suitable fabric +stretched over the same to form the body of the rudder. The rudder is +supported from the struts 29 by means of the intermediate cross-piece +32, which is located near the centre of pressure slightly in front of +a line equidistant between the front and rear edges of the rudder, +the cross-piece 32 forming the pivotal axis of the rudder, so as to +constitute a balanced rudder. To the front edge of the rudder there are +connected springs 36 which springs are connected to the upturned ends 30 +of the struts 28, the construction being such that said springs tend to +resist any movement either upward or downward of the front edge of the +horizontal rudder. The rear edge of the rudder lies immediately in front +of the operator and may be operated by him in any suitable manner. We +have shown a mechanism for this purpose comprising a roller or shaft 37, +which may be grasped by the operator so as to turn the same in either +direction. Bands 38 extend from the roller 37 forward to and around a +similar roller or shaft 39, both rollers or shafts being supported in +suitable bearings on the struts 28. The forward roller or shaft has +rearwardly-extending arms 40, which are connected by links 41 with the +rear edge of the rudder 31. The normal position of the rudder 31 is +neutral or substantially parallel with the aeroplanes 1 and 2; but its +rear edge may be moved upward or downward, so as to be above or below +the normal plane of said rudder through the mechanism provided for that +purpose. It will be seen that the springs 36 will resist any tendency of +the forward edge of the rudder to move in either direction, so that when +force is applied to the rear edge of said rudder the longitudinal ribs +35 bend, and the rudder thus presents a concave surface to the action of +the wind either above or below its normal plane, said surface presenting +a small angle of incidence at its forward portion and said angle of +incidence rapidly increasing toward the rear. This greatly increases the +efficiency of the rudder as compared with a plane surface of equal area. +By regulating the pressure on the upper and lower sides of the rudder +through changes of angle and curvature in the manner described a +turning movement of the main structure around its transverse axis may be +effected, and the course of the machine may thus be directed upward +or downward at the will of the operator and the longitudinal balance +thereof maintained. + +Contrary to the usual custom, we place the horizontal rudder in front of +the aeroplanes at a negative angle and employ no horizontal tail at all. +By this arrangement we obtain a forward surface which is almost entirely +free from pressure under ordinary conditions of flight, but which even +if not moved at all from its original position becomes an efficient +lifting-surface whenever the speed of the machine is accidentally +reduced very much below the normal, and thus largely counteracts that +backward travel of the centre of pressure on the aeroplanes which has +frequently been productive of serious injuries by causing the machine +to turn downward and forward and strike the ground head-on. We are aware +that a forward horizontal rudder of different construction has been used +in combination with a supporting surface and a rear horizontal-rudder; +but this combination was not intended to effect and does not effect the +object which we obtain by the arrangement hereinbefore described. + +We have used the term 'aeroplane' in this specification and the appended +claims to indicate the supporting surface or supporting surfaces by +means of which the machine is sustained in the air, and by this term we +wish to be understood as including any suitable supporting surface which +normally is substantially flat, although. Of course, when constructed +of cloth or other flexible fabric, as we prefer to construct them, these +surfaces may receive more or less curvature from the resistance of the +air, as indicated in Fig. 3. + +We do not wish to be understood as limiting ourselves strictly to the +precise details of construction hereinbefore described and shown in +the accompanying drawings, as it is obvious that these details may be +modified without departing from the principles of our invention. For +instance, while we prefer the construction illustrated in which each +aeroplane is given a twist along its entire length in order to set its +opposite lateral margins at different angles, we have already pointed +out that our invention is not limited to this form of construction, +since it is only necessary to move the lateral marginal portions, and +where these portions alone are moved only those upright standards which +support the movable portion require flexible connections at their ends. + +Having thus fully described our invention, what we claim as new, and +desire to secure by Letters Patent, is:-- + +1. In a flying machine, a normally flat aeroplane having lateral +marginal portions capable of movement to different positions above or +below the normal plane of the body of the aeroplane, such movement being +about an axis transverse to the line of flight, whereby said lateral +marginal portions may be moved to different angles relatively to the +normal plane of the body of the aeroplane, so as to present to the +atmosphere different angles of incidence, and means for so moving said +lateral marginal portions, substantially as described. + +2. In a flying machine, the combination, with two normally parallel +aeroplanes, superposed the one above the other, of upright standards +connecting said planes at their margins, the connections between the +standards and aeroplanes at the lateral portions of the aeroplanes being +by means of flexible joints, each of said aeroplanes having lateral +marginal portions capable of movement to different positions above or +below the normal plane of the body of the aeroplane, such movement being +about an axis transverse to the line of flight, whereby said lateral +marginal portions may be moved to different angles relatively to the +normal plane of the body of the aeroplane, so as to present to the +atmosphere different angles of incidence, the standards maintaining +a fixed distance between the portions of the aeroplanes which they +connect, and means for imparting such movement to the lateral marginal +portions of the aeroplanes, substantially as described. + +3. In a flying machine, a normally flat aeroplane having lateral +marginal portions capable of movement to different positions above or +below the normal plane of the body of the aeroplane, such movement being +about an axis transverse to the line of flight, whereby said lateral +marginal portions may be moved to different angles relatively to the +normal plane of the body of the aeroplane, and also to different angles +relatively to each other, so as to present to the atmosphere different +angles of incidence, and means for simultaneously imparting such +movement to said lateral marginal portions, substantially as described. + +4. In a flying machine, the combination, with parallel superposed +aeroplanes, each having lateral marginal portions capable of movement to +different positions above or below the normal plane of the body of the +aeroplane, such movement being about an axis transverse to the line of +flight, whereby said lateral marginal portions may be moved to different +angles relatively to the normal plane of the body of the aeroplane, and +to different angles relatively to each other, so as to present to the +atmosphere different angles of incidence, of uprights connecting said +aeroplanes at their edges, the uprights connecting the lateral portions +of the aeroplanes being connected with said aeroplanes by flexible +joints, and means for simultaneously imparting such movement to said +lateral marginal portions, the standards maintaining a fixed distance +between the parts which they connect, whereby the lateral portions on +the same side of the machine are moved to the same angle, substantially +as described. + +5. In a flying machine, an aeroplane having substantially the form of a +normally flat rectangle elongated transversely to the line of flight, +in combination which means for imparting to the lateral margins of said +aeroplane a movement about an axis lying in the body of the aeroplane +perpendicular to said lateral margins, and thereby moving said lateral +margins into different angular relations to the normal plane of the body +of the aeroplane, substantially as described. + +6. In a flying machine, the combination, with two superposed and +normally parallel aeroplanes, each having substantially the form of a +normally flat rectangle elongated transversely to the line of flight, +of upright standards connecting the edges of said aeroplanes to maintain +their equidistance, those standards at the lateral portions of said +aeroplanes being connected therewith by flexible joints, and means for +simultaneously imparting to both lateral margins of both aeroplanes a +movement about axes which are perpendicular to said margins and in the +planes of the bodies of the respective aeroplanes, and thereby moving +the lateral margins on the opposite sides of the machine into different +angular relations to the normal planes of the respective aeroplanes, the +margins on the same side of the machine moving to the same angle, and +the margins on one side of the machine moving to an angle different from +the angle to which the margins on the other side of the machine move, +substantially as described. + +7. In a flying machine, the combination, with an aeroplane, and means +for simultaneously moving the lateral portions thereof into different +angular relations to the normal plane of the body of the aeroplane and +to each other, so as to present to the atmosphere different angles of +incidence, of a vertical rudder, and means whereby said rudder is +caused to present to the wind that side thereof nearest the side of the +aeroplane having the smaller angle of incidence and offering the least +resistance to the atmosphere, substantially as described. + +8. In a flying machine, the combination, with two superposed and +normally parallel aeroplanes, upright standards connecting the edges of +said aeroplanes to maintain their equidistance, those standards at +the lateral portions of said aeroplanes being connected therewith +by flexible joints, and means for simultaneously moving both lateral +portions of both aeroplanes into different angular relations to the +normal planes of the bodies of the respective aeroplanes, the lateral +portions on one side of the machine being moved to an angle different +from that to which the lateral portions on the other side of the machine +are moved, so as to present different angles of incidence at the two +sides of the machine, of a vertical rudder, and means whereby said +rudder is caused to present to the wind that side thereof nearest +the side of the aeroplanes having the smaller angle of incidence and +offering the least resistance to the atmosphere, substantially as +described. + +9. In a flying machine, an aeroplane normally flat and elongated +transversely to the line of flight, in combination with means for +imparting to said aeroplane a helicoidal warp around an axis transverse +to the line of flight and extending centrally along the body aeroplane +in the direction of the elongation aeroplane, substantially as +described. + +10. In a flying machine, two aeroplanes, each normally flat and +elongated transversely to the line of flight, and upright standards +connecting the edges of said aeroplanes to maintain their equidistance, +the connections between said standards and aeroplanes being by means of +flexible joints, in combination with means for simultaneously imparting +to each of said aeroplanes a helicoidal warp around an axis transverse +to the line of flight and extending centrally along the body of the +aeroplane in the direction of the aeroplane, substantially as described. + +11. In a flying machine, two aeroplanes, each normally flat and +elongated transversely to the line of flight, and upright standards +connecting the edges of said aeroplanes to maintain their equidistance, +the connections between such standards and aeroplanes being by means of +flexible joints, in combination with means for simultaneously imparting +to each of said aeroplanes a helicoidal warp around an axis transverse +to the line of flight and extending centrally along the body of the +aeroplane in the direction of the elongation of the aeroplane, a +vertical rudder, and means whereby said rudder is caused to present to +the wind that side thereof nearest the side of the aeroplanes having +the smaller angle of incidence and offering the least resistance to the +atmosphere, substantially as described. + +12. In a flying machine, the combination, with an aeroplane, of a +normally flat and substantially horizontal flexible rudder, and means +for curving said rudder rearwardly and upwardly or rearwardly and +downwardly with respect to its normal plane, substantially as described. + +13. In a flying machine, the combination, with an aeroplane, of a +normally flat and substantially horizontal flexible rudder pivotally +mounted on an axis transverse to the line of flight near its centre, +springs resisting vertical movement of the front edge of said rudder, +and means for moving the rear edge of said rudder, above or below the +normal plane thereof, substantially as described. + +14. A flying machine comprising superposed connected aeroplanes means +for moving the opposite lateral portions of said aeroplanes to different +angles to the normal planes thereof, a vertical rudder, means for moving +said vertical rudder toward that side of the machine presenting the +smaller angle of incidence and the least resistance to the atmosphere, +and a horizontal rudder provided with means for presenting its upper +or under surface to the resistance of the atmosphere, substantially as +described. + +15. A flying machine comprising superposed connected aeroplanes, means +for moving the opposite lateral portions of said aeroplanes to different +angles to the normal planes thereof, a vertical rudder, means for moving +said vertical rudder toward that side of the machine presenting the +smaller angle of incidence and the least resistance to the atmosphere, +and a horizontal rudder provided with means for presenting its upper or +under surface to the resistance of the atmosphere, said vertical rudder +being located at the rear of the machine and said horizontal rudder at +the front of the machine, substantially as described. + +16. In a flying machine, the combination, with two superposed and +connected aeroplanes, of an arm extending rearward from each aeroplane, +said arms being parallel and free to swing upward at their rear ends, +and a vertical rudder pivotally mounted in the rear ends of said arms, +substantially as described. + +17. A flying machine comprising two superposed aeroplanes, normally +flat but flexible, upright standards connecting the margins of said +aeroplanes, said standards being connected to said aeroplanes by +universal joints, diagonal stay-wires connecting the opposite ends of +the adjacent standards, a rope extending along the front edge of the +lower aeroplane, passing through guides at the front corners thereof, +and having its ends secured to the rear corners of the upper aeroplane, +and a rope extending along the rear edge of the lower aeroplane, passing +through guides at the rear corners thereof, and having its ends secured +to the front corners of the upper aeroplane, substantially as described. + +18. A flying machine comprising two superposed aeroplanes, normally +flat but flexible, upright standards connecting the margins of said +aeroplanes, said standards being connected to said aeroplanes by +universal joints, diagonal stay-wires connecting the opposite ends of +the adjacent standards, a rope extending along the front edge of the +lower aeroplane, passing through guides at the front corners thereof, +and having its ends secured to the rear corners of the upper aeroplane, +and a rope extending along the rear edge of the lower aeroplane, passing +through guides at the rear corners thereof, and having its ends secured +to the front corners of the upper aeroplane, in combination with a +vertical rudder, and a tiller-rope connecting said rudder with the rope +extending along the rear edge of the lower aeroplane, substantially as +described. + + ORVILLE WRIGHT. + + WILBUR WRIGHT. + +Witnesses: + +Chas. E. Taylor. + +E. Earle Forrer. + + + + +APPENDIX C + +Proclamation published by the French Government on balloon ascents, +1783. + + NOTICE TO THE PUBLIC! PARIS, 27TH AUGUST, 1783. + +On the Ascent of balloons or globes in the air. The one in question +has been raised in Paris this day, 27th August, 1783, at 5 p.m., in the +Champ de Mars. + +A Discovery has been made, which the Government deems it right to make +known, so that alarm be not occasioned to the people. + +On calculating the different weights of hot air, hydrogen gas, and +common air, it has been found that a balloon filled with either of the +two former will rise toward heaven till it is in equilibrium with the +surrounding air, which may not happen until it has attained a great +height. + +The first experiment was made at Annonay, in Vivarais, MM. Montgolfier, +the inventors; a globe formed of canvas and paper, 105 feet in +circumference, filled with heated air, reached an uncalculated height. +The same experiment has just been renewed in Paris before a great crowd. +A globe of taffetas or light canvas covered by elastic gum and filled +with inflammable air, has risen from the Champ de Mars, and been lost +to view in the clouds, being borne in a north-westerly direction. One +cannot foresee where it will descend. + +It is proposed to repeat these experiments on a larger scale. Any +one who shall see in the sky such a globe, which resembles 'la lune +obscurcie,' should be aware that, far from being an alarming phenomenon, +it is only a machine that cannot possibly cause any harm, and which will +some day prove serviceable to the wants of society. + +(Signed) DE SAUVIGNY. + +LENOIR. + + + + + +End of Project Gutenberg's A History of Aeronautics, by E. 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Charles Vivian + + + + +FOREWORD + +Although successful heavier-than-air flight is less than two +decades old, and successful dirigible propulsion antedates it by +a very short period, the mass of experiment and accomplishment +renders any one-volume history of the subject a matter of +selection. In addition to the restrictions imposed by space +limits, the material for compilation is fragmentary, and, in +many cases, scattered through periodical and other publications. +Hitherto, there has been no attempt at furnishing a detailed +account of how the aeroplane and the dirigible of to-day came to +being, but each author who has treated the subject has devoted +his attention to some special phase or section. The principal +exception to this rule--Hildebrandt--wrote in 1906, and a good +many of his statements are inaccurate, especially with regard to +heavier-than-air experiment. + +Such statements as are made in this work are, where possible, +given with acknowledgment to the authorities on which they rest. +Further acknowledgment is due to Lieut.-Col. Lockwood Marsh, +not only for the section on aeroplane development which he has +contributed to the work, but also for his kindly assistance and +advice in connection with the section on aerostation. The +author's thanks are also due to the Royal Aeronautical Society +for free access to its valuable library of aeronautical +literature, and to Mr A. Vincent Clarke for permission to make +use of his notes on the development of the aero engine. + +In this work is no claim to originality--it has been a matter +mainly of compilation, and some stories, notably those of the +Wright Brothers and of Santos Dumont, are better told in the +words of the men themselves than any third party could tell +them. The author claims, however, that this is the first +attempt at recording the facts of development and stating, as +fully as is possible in the compass of a single volume, how +flight and aerostation have evolved. The time for a critical +history of the subject is not yet. + +In the matter of illustrations, it has been found very difficult +to secure suitable material. Even the official series of +photographs of aeroplanes in the war period is curiously +incomplete' and the methods of censorship during that period +prevented any complete series being privately collected. +Omissions in this respect will probably be remedied in future +editions of the work, as fresh material is constantly being +located. + +E.C.V. October, 1920. + +CONTENTS +Part I--THE EVOLUTION OF THE AEROPLANE + I. THE PERIOD OF LEGEND + II. EARLY EXPERIMENTS + III. SIR GEORGE CAYLEY--THOMAS WALKER + IV. THE MIDDLE NINETEENTH CENTURY + V. WENHAM, LE BRIS, AND SOME OTHERS + VI. THE AGE OF THE GIANTS + VII. LILIENTHAL AND PILCHER + VIII. AMERICAN GLIDING EXPERIMENTS + IX. NOT PROVEN + X. SAMUEL PIERPOINT LANGLEY + XI. THE WRIGHT BROTHERS + XII. THE FIRST YEARS OF CONQUEST + XIII. FIRST FLIERS IN ENGLAND + XIV. RHEIMS, AND AFTER + XV. THE CHANNEL CROSSING + XVI. LONDON TO MANCHESTER + XVII. A SUMMARY--TO 1911 +XVIII. A SUMMARY--TO 1914 + XIX. THE WAR PERIOD--I + XX. THE WAR PERIOD--II + XXI. RECONSTRUCTION + XXII. 1919-1920 + +Part II--1903-1920: PROGRESS IN DESIGN + I. THE BEGINNINGS + II. MULTIPLICITY OF IDEAS + III. PROGRESS ON STANDARDISED LINES + IV. THE WAR PERIOD + +Part III--AEROSTATICS + I. BEGINNINGS + II. THE FIRST DIRIGIBLES + III. SANTOS-DUMONT + IV. THE MILITARY DIRIGIBLE + V. BRITISH AIRSHIP DESIGN + VI. THE AIRSHIP COMMERCIALLY + VII. KITE BALLOONS + +PART IV--ENGINE DEVELOPMENT + I. THE VERTICAL TYPE + II. THE VEE TYPE + III. THE RADIAL TYPE + IV. THE ROTARY TYPE + V. THE HORIZONTALLY-OPPOSED ENGINE + VI. THE TWO-STROKE CYCLE ENGINE + VII. ENGINES OF THE WAR PERIOD + +APPENDICES + + + +PART I + +THE EVOLUTION OF THE AEROPLANE + +I. THE PERIOD OF LEGEND + +The blending of fact and fancy which men call legend reached its +fullest and richest expression in the golden age of Greece, and +thus it is to Greek mythology that one must turn for the best +form of any legend which foreshadows history. Yet the +prevalence of legends regarding flight, existing in the records +of practically every race, shows that this form of transit was a +dream of many peoples--man always wanted to fly, and imagined +means of flight. + +In this age of steel, a very great part of the inventive genius +of man has gone into devices intended to facilitate transport, +both of men and goods, and the growth of civilisation is in +reality the facilitation of transit, improvement of the means of +communication. He was a genius who first hoisted a sail on a +boat and saved the labour of rowing; equally, he who first +harnessed ox or dog or horse to a wheeled vehicle was a +genius--and these looked up, as men have looked up from the +earliest days of all, seeing that the birds had solved the +problem of transit far more completely than themselves. So it +must have appeared, and there is no age in history in which some +dreamers have not dreamed of the conquest of the air; if the +caveman had left records, these would without doubt have showed +that he, too, dreamed this dream. His main aim, probably, was +self-preservation; when the dinosaur looked round the corner, +the prehistoric bird got out of the way in his usual manner, and +prehistoric manÄ such of him as succeeded in getting out of the +way after his fashion--naturally envied the bird, and concluded +that as lord of creation in a doubtful sort of way he ought to +have equal facilities. He may have tried, like Simon the +Magician, and other early experimenters, to improvise those +facilities; assuming that he did, there is the groundwork of +much of the older legend with regard to men who flew, since, +when history began, legends would be fashioned out of attempts +and even the desire to fly, these being compounded of some small +ingredient of truth and much exaggeration and addition. + +In a study of the first beginnings of the art, it is worth while +to mention even the earliest of the legends and traditions, for +they show the trend of men's minds and the constancy of this +dream that has become reality in the twentieth century. In one +of the oldest records of the world, the Indian classic +Mahabarata, it is stated that 'Krishna's enemies sought the aid +of the demons, who built an aerial chariot with sides of iron +and clad with wings. The chariot was driven through the sky till +it stood over Dwarakha, where Krishna's followers dwelt, and +from there it hurled down upon the city missiles that destroyed +everything on which they fell.' Here is pure fable, not legend, +but still a curious forecast of twentieth century bombs from a +rigid dirigible. It is to be noted in this case, as in many, +that the power to fly was an attribute of evil, not of good--it +was the demons who built the chariot, even as at Friedrichshavn. +Mediaeval legend in nearly every cas,attributes flight to the +aid of evil powers, and incites well-disposed people to stick to +the solid earth--though, curiously enough, the pioneers of +medieval times were very largely of priestly type, as witness +the monk of Malmesbury. + +The legends of the dawn of history, however, distribute the +power of flight with less of prejudice. Egyptian sculpture gives +the figure of winged men; the British Museum has made the winged +Assyrian bulls familiar to many, and both the cuneiform records +of Assyria and the hieroglyphs of Egypt record flights that in +reality were never made. The desire fathered the story then, +and until Clement Ader either hopped with his Avion, as is +persisted by his critics, or flew, as is claimed by his friends. + +While the origin of many legends is questionable, that of others +is easy enough to trace, though not to prove. Among the +credulous the significance of the name of a people of Asia +Minor, the Capnobates, 'those who travel by smoke,' gave rise to +the assertion that Montgolfier was not first in the field--or +rather in the air--since surely this people must have been +responsible for the first hot-air balloons. Far less +questionable is the legend of Icarus, for here it is possible to +trace a foundation of fact in the story. Such a tribe as +Daedalus governed could have had hardly any knowledge of the +rudiments of science, and even their ruler, seeing how easy it +is for birds to sustain themselves in the air, might be excused +for believing that he, if he fashioned wings for himself, could +use them. In that belief, let it be assumed, Daedalus made his +wings; the boy, Icarus, learning that his father had determined +on an attempt at flight secured the wings and fastened them to +his own shoulders. A cliff seemed the likeliest place for a +'take-off,' and Icarus leaped from the cliff edge only to find +that the possession of wings was not enough to assure flight to +a human being. The sea that to this day bears his name +witnesses that he made the attempt and perished by it. + +In this is assumed the bald story, from which might grow the +legend of a wise king who ruled a peaceful people--'judged, +sitting in the sun,' as Browning has it, and fashioned for +himself wings with which he flew over the sea and where he +would, until the prince, Icarus, desired to emulate him. +Icarus, fastening the wings to his shoulders with wax, was so +imprudent as to fly too near the sun, when the wax melted and he +fell, to lie mourned of water-nymphs on the shores of waters +thenceforth Icarian. Between what we have assumed to be the +base of fact, and the legend which has been invested with such +poetic grace in Greek story, there is no more than a century or +so of re-telling might give to any event among a people so +simple and yet so given to imagery. + +We may set aside as pure fable the stories of the winged horse +of Perseus, and the flights of Hermes as messenger of the gods. +With them may be placed the story of Empedocles, who failed to +take Etna seriously enough, and found himself caught by an +eruption while within the crater, so that, flying to safety in +some hurry, he left behind but one sandal to attest that he had +sought refuge in space--in all probability, if he escaped at +all, he flew, but not in the sense that the aeronaut understands +it. But, bearing in mind the many men who tried to fly in +historic times, the legend of Icarus and Daedalus, in spite of +the impossible form in which it is presented, may rank with the +story of the Saracen of Constantinople, or with that of Simon +the Magician. A simple folk would naturally idealise the man +and magnify his exploit, as they magnified the deeds of some +strong man to make the legends of Hercules, and there, +full-grown from a mere legend, is the first record of a pioneer +of flying. Such a theory is not nearly so fantastic as that +which makes the Capnobates, on the strength of their name, the +inventors of hot-air balloons. However it may be, both in story +and in picture, Icarus and his less conspicuous father have +inspired the Caucasian mind, and the world is the richer for +them. + +Of the unsupported myths--unsupported, that is, by even a shadow +of probability--there is no end. Although Latin legend +approaches nearer to fact than the Greek in some cases, in +others it shows a disregard for possibilities which renders it +of far less account. Thus Diodorus of Sicily relates that one +Abaris travelled round the world on an arrow of gold, and +Cassiodorus and Glycas and their like told of mechanical birds +that flew and sang and even laid eggs. More credible is the +story of Aulus Gellius, who in his Attic Nights tells how +Archytas, four centuries prior to the opening of the Christian +era, made a wooden pigeon that actually flew by means of a +mechanism of balancing weights and the breath of a mysterious +spirit hidden within it. There may yet arise one credulous +enough to state that the mysterious spirit was precursor of the +internal combustion engine, but, however that may be, the pigeon +of Archytas almost certainly existed, and perhaps it actually +glided or flew for short distances--or else Aulus Gellius was an +utter liar, like Cassiodorus and his fellows. In far later +times a certain John Muller, better known as Regiomontanus, is +stated to have made an artificial eagle which accompanied +Charles V. on his entry to and exit from Nuremberg, flying above +the royal procession. But, since Muller died in 1436 and +Charles was born in 1500, Muller may be ruled out from among the +pioneers of mechanical flight, and it may be concluded that the +historian of this event got slightly mixed in his dates. + +Thus far, we have but indicated how one may draw from the +richest stores from which the Aryan mind draws inspiration, the +Greek and Latin mythologies and poetic adaptations of history. +The existing legends of flight, however, are not thus to be +localised, for with two possible exceptions they belong to all +the world and to every civilisation, however primitive. The two +exceptions are the Aztec and the Chinese; regarding the first of +these, the Spanish conquistadores destroyed such civilisation as +existed in Tenochtitlan so thoroughly that, if legend of flight +was among the Aztec records, it went with the rest; as to the +Chinese, it is more than passing strange that they, who claim to +have known and done everything while the first of history was +shaping, even to antedating the discovery of gunpowder that was +not made by Roger Bacon, have not yet set up a claim to +successful handling of a monoplane some four thousand years ago, +or at least to the patrol of the Gulf of Korea and the Mongolian +frontier by a forerunner of the 'blimp.' + +The Inca civilisation of Peru yields up a myth akin to that of +Icarus, which tells how the chieftain Ayar Utso grew wings and +visited the sun--it was from the sun, too, that the founders of +the Peruvian Inca dynasty, Manco Capac and his wife Mama Huella +Capac, flew to earth near Lake Titicaca, to make the only +successful experiment in pure tyranny that the world has ever +witnessed. Teutonic legend gives forth Wieland the Smith, who +made himself a dress with wings and, clad in it, rose and +descended against the wind and in spite of it. Indian mythology, +in addition to the story of the demons and their rigid dirigible, +already quoted, gives the story of Hanouam, who fitted himself +with wings by means of which he sailed in the air and, according +to his desire, landed in the sacred Lauka. Bladud, the ninth +king of Britain, is said to have crowned his feats of wizardry by +making himself wings and attempting to fly--but the effort cost +him a broken neck. Bladud may have been as mythic as Uther, and +again he may have been a very early pioneer. The Finnish epic, +'Kalevala,' tells how Ilmarinen the Smith 'forged an eagle of +fire,' with 'boat's walls between the wings,' after which he +'sat down on the bird's back and bones,' and flew. + +Pure myths, these, telling how the desire to fly was +characteristic of every age and every people, and how, from time +to time, there arose an experimenter bolder than his fellows, +who made some attempt to translate desire into achievement. And +the spirit that animated these pioneers, in a time when things +new were accounted things accursed, for the most part, has found +expression in this present century in the utter daring and +disregard of both danger and pain that stamps the flying man, a +type of humanity differing in spirit from his earthbound fellows +as fully as the soldier differs from the priest. + +Throughout mediaeval times, records attest that here and there +some man believed in and attempted flight, and at the same +time it is clear that such were regarded as in league with the +powers of evil. There is the half-legend, half-history of +Simon the Magician, who, in the third year of the reign of Nero +announced that he would raise himself in the air, in order to +assert his superiority over St Paul. The legend states that by +the aid of certain demons whom he had prevailed on to assist +him, he actually lifted himself in the air-- but St Paul prayed +him down again. He slipped through the claws of the demons and +fell headlong on the Forum at Rome, breaking his neck. The +'demons' may have been some primitive form of hot-air balloon, +or a glider with which the magician attempted to rise into the +wind; more probably, however, Simon threatened to ascend and +made the attempt with apparatus as unsuitable as Bladud's wings, +paying the inevitable penalty. Another version of the story +gives St Peter instead of St Paul as the one whose prayers +foiled Simon --apart from the identity of the apostle, the two +accounts are similar, and both define the attitude of the age +toward investigation and experiment in things untried. + +Another and later circumstantial story, with similar evidence of +some fact behind it, is that of the Saracen of Constantinople, +who, in the reign of the Emperor Comnenus--some little time +before Norman William made Saxon Harold swear away his crown on +the bones of the saints at Rouen--attempted to fly round the +hippodrome at Constantinople, having Comnenus among the great +throng who gathered to witness the feat. The Saracen chose for +his starting-point a tower in the midst of the hippodrome, and +on the top of the tower he stood, clad in a long white robe which +was stiffened with rods so as to spread and catch the breeze, +waiting for a favourable wind to strike on him. The wind was so +long in coming that the spectators grew impatient. 'Fly, O +Saracen!' they called to him. 'Do not keep us waiting so long +while you try the wind!' Comnenus, who had present with him the +Sultan of the Turks, gave it as his opinion that the experiment +was both dangerous and vain, and, possibly in an attempt to +controvert such statement, the Saracen leaned into the wind and +'rose like a bird 'at the outset. But the record of Cousin, who +tells the story in his Histoire de Constantinople, states that +'the weight of his body having more power to drag him down than +his artificial wings had to sustain him, he broke his bones, and +his evil plight was such that he did not long survive.' + +Obviously, the Saracen was anticipating Lilienthal and his +gliders by some centuries; like Simon, a genuine +experimenter--both legends bear the impress of fact supporting +them. Contemporary with him, and belonging to the history +rather than the legends of flight, was Oliver, the monk of +Malmesbury, who in the year 1065 made himself wings after the +pattern of those supposed to have been used by Daedalus, +attaching them to his hands and feet and attempting to fly with +them. Twysden, in his Historiae Anglicanae Scriptores X, sets +forth the story of Oliver, who chose a high tower as his +starting-point, and launched himself in the air. As a matter of +course, he fell, permanently injuring himself, and died some +time later. + +After these, a gap of centuries, filled in by impossible stories +of magical flight by witches, wizards, and the like--imagination +was fertile in the dark ages, but the ban of the church was on +all attempt at scientific development, especially in such a +matter as the conquest of the air. Yet there were observers of +nature who argued that since birds could raise themselves by +flapping their wings, man had only to make suitable wings, flap +them, and he too would fly. As early as the thirteenth century +Roger Bacon, the scientific friar of unbounded inquisitiveness +and not a little real genius, announced that there could be made +'some flying instrument, so that a man sitting in the middle and +turning some mechanism may put in motion some artificial wings +which may beat the air like a bird flying.' But being a cautious +man, with a natural dislike for being burnt at the stake as a +necromancer through having put forward such a dangerous theory, +Roger added, 'not that I ever knew a man who had such an +instrument, but I am particularly acquainted with the man who +contrived one.' This might have been a lame defence if Roger had +been brought to trial as addicted to black arts; he seems to +have trusted to the inadmissibility of hearsay evidence. + +Some four centuries later there was published a book entitled +Perugia Augusta, written by one C. Crispolti of Perugia--the +date of the work in question is 1648. In it is recorded that +'one day, towards the close of the fifteenth century, whilst +many of the principal gentry had come to Perugia to honour the +wedding of Giovanni Paolo Baglioni, and some lancers were riding +down the street by his palace, Giovanni Baptisti Danti +unexpectedly and by means of a contrivance of wings that he had +constructed proportionate to the size of his body took off from +the top of a tower near by, and with a horrible hissing sound +flew successfully across the great Piazza, which was densely +crowded. But (oh, horror of an unexpected accident!) he had +scarcely flown three hundred paces on his way to a certain point +when the mainstay of the left wing gave way, and, being unable to +support himself with the right alone, he fell on a roof and was +injured in consequence. Those who saw not only this flight, but +also the wonderful construction of the framework of the wings, +said--and tradition bears them out--that he several times flew +over the waters of Lake Thrasimene to learn how he might +gradually come to earth. But, notwithstanding his great genius, +he never succeeded.' + +This reads circumstantially enough, but it may be borne in mind +that the date of writing is more than half a century later than +the time of the alleged achievement--the story had had time to +round itself out. Danti, however, is mentioned by a number of +writers, one of whom states that the failure of his experiment +was due to the prayers of some individual of a conservative turn +of mind, who prayed so vigorously that Danti fell appropriately +enough on a church and injured himself to such an extent as to +put an end to his flying career. That Danti experimented, there +is little doubt, in view of the volume of evidence on the point, +but the darkness of the Middle Ages hides the real truth as to +the results of his experiments. If he had actually flown over +Thrasimene, as alleged, then in all probability both Napoleon +and Wellington would have had air scouts at Waterloo. + +Danti's story may be taken as fact or left as fable, and with it +the period of legend or vague statement may be said to end--the +rest is history, both of genuine experimenters and of +charlatans. Such instances of legend as are given here are not a +tithe of the whole, but there is sufficient in the actual history +of flight to bar out more than this brief mention of the legends, +which, on the whole, go farther to prove man's desire to fly than +his study and endeavour to solve the problems of the air. + + + +II. EARLY EXPERIMENTS + +So far, the stories of the development of flight are either +legendary or of more or less doubtful authenticity, even +including that of Danti, who, although a man of remarkable +attainments in more directions than that of attempted flight, +suffers--so far as reputation is concerned--from the +inexactitudes of his chroniclers; he may have soared over +Thrasimene, as stated, or a mere hop with an ineffectual glider +may have grown with the years to a legend of gliding flight. So +far, too, there is no evidence of the study that the conquest of +the air demanded; such men as made experiments either launched +themselves in the air from some height with made-up wings or +other apparatus, and paid the penalty, or else constructed some +form of machine which would not leave the earth, and then gave +up. Each man followed his own way, and there was no +attempt--without the printing press and the dissemination of +knowledge there was little possibility of attempt--on the part +of any one to benefit by the failures of others. + +Legend and doubtful history carries up to the fifteenth century, +and then came Leonardo da Vinci, first student of flight whose +work endures to the present day. The world knows da Vinci as +artist; his age knew him as architect, engineer, artist, and +scientist in an age when science was a single study, comprising +all knowledge from mathematics to medicine. He was, of course, +in league with the devil, for in no other way could his range of +knowledge and observation be explained by his contemporaries; he +left a Treatise on the Flight of Birds in which are statements +and deductions that had to be rediscovered when the Treatise had +been forgotten--da Vinci anticipated modern knowledge as Plato +anticipated modern thought, and blazed the first broad trail +toward flight. + +One Cuperus, who wrote a Treatise on the Excellence of Man, +asserted that da Vinci translated his theories into practice, +and actually flew, but the statement is unsupported. That he +made models, especially on the helicopter principle, is past +question; these were made of paper and wire, and actuated by +springs of steel wire, which caused them to lift themselves in +the air. It is, however, in the theories which he put forward +that da Vinci's investigations are of greatest interest; these +prove him a patient as well as a keen student of the principles +of flight, and show that his manifold activities did not prevent +him from devoting some lengthy periods to observations of bird +flight. + +'A bird,' he says in his Treatise, 'is an instrument working +according to mathematical law, which instrument it is within the +capacity of man to reproduce with all its movements, but not +with a corresponding degree of strength, though it is deficient +only in power of maintaining equilibrium. We may say, +therefore, that such an instrument constructed by man is lacking +in nothing except the life of the bird, and this life must needs +be supplied from that of man. The life which resides in the +bird's members will, without doubt, better conform to their needs +than will that of a man which is separated from them, and +especially in the almost imperceptible movements which produce +equilibrium. But since we see that the bird is equipped for many +apparent varieties of movement, we are able from this experience +to deduce that the most rudimentary of these movements will be +capable of being comprehended by man's understanding, and that he +will to a great extent be able to provide against the destruction +of that instrument of which he himself has become the living +principle and the propeller.' + +In this is the definite belief of da Vinci that man is capable +of flight, together with a far more definite statement of the +principles by which flight is to be achieved than any which had +preceded it--and for that matter, than many that have succeeded +it. Two further extracts from his work will show the exactness +of his observations:-- + +'When a bird which is in equilibrium throws the centre of +resistance of the wings behind the centre of gravity, then such +a bird will descend with its head downward. This bird which +finds itself in equilibrium shall have the centre of resistance +of the wings more forward than the bird's centre of gravity; +then such a bird will fall with its tail turned toward the +earth.' + +And again: 'A man, when flying, shall be free from the waist +up, that he may be able to keep himself in equilibrium as he +does in a boat, so that the centre of his gravity and of the +instrument may set itself in equilibrium and change when +necessity requires it to the changing of the centre of its +resistance.' + +Here, in this last quotation, are the first beginnings of the +inherent stability which proved so great an advance in design, +in this twentieth century. But the extracts given do not begin +to exhaust the range of da Vinci's observations and deductions. +With regard to bird flight, he observed that so long as a bird +keeps its wings outspread it cannot fall directly to earth, but +must glide down at an angle to alight--a small thing, now that +the principle of the plane in opposition to the air is generally +grasped, but da Vinci had to find it out. From observation he +gathered how a bird checks its own speed by opposing tail and +wing surface to the direction of flight, and thus alights at the +proper 'landing speed.' He proved the existence of upward air +currents by noting how a bird takes off from level earth with +wings outstretched and motionless, and, in order to get an +efficient substitute for the natural wing, he recommended that +there be used something similar to the membrane of the wing of a +bat--from this to the doped fabric of an aeroplane wing is but +a small step, for both are equally impervious to air. Again, da +Vinci recommended that experiments in flight be conducted at a +good height from the ground, since, if equilibrium be lost +through any cause, the height gives time to regain it. This +recommendation, by the way, received ample support in the +training areas of war pilots. + +Man's muscles, said da Vinci, are fully sufficient to enable him +to fly, for the larger birds, he noted, employ but a small part +of their strength in keeping themselves afloat in the air--by +this theory he attempted to encourage experiment, just as, when +his time came, Borelli reached the opposite conclusion and +discouraged it. That Borelli was right--so far--and da Vinci +wrong, detracts not at all from the repute of the earlier +investigator, who had but the resources of his age to support +investigations conducted in the spirit of ages after. + +His chief practical contributions to the science of +flight--apart from numerous drawings which have still a +value--are the helicopter or lifting screw, and the parachute. +The former, as already noted, he made and proved effective in +model form, and the principle which he demonstrated is that of +the helicopter of to-day, on which sundry experimenters work +spasmodically, in spite of the success of the plane with its +driving propeller. As to the parachute, the idea was doubtless +inspired by observation of the effect a bird produced by +pressure of its wings against the direction of flight. + +Da Vinci's conclusions, and his experiments, were forgotten +easily by most of his contemporaries; his Treatise lay forgotten +for nearly four centuries, overshadowed, mayhap, by his other +work. There was, however, a certain Paolo Guidotti of Lucca, +who lived in the latter half of the sixteenth century, and who +attempted to carry da Vinci's theories--one of them, at least, +into practice. For this Guidotti, who was by profession an +artist and by inclination an investigator, made for himself +wings, of which the framework was of whalebone; these he covered +with feathers, and with them made a number of gliding flights, +attaining considerable proficiency. He is said in the end to +have made a flight of about four hundred yards, but this attempt +at solving the problem ended on a house roof, where Guidotti +broke his thigh bone. After that, apparently, he gave up the +idea of flight, and went back to painting. + +One other a Venetian architect named Veranzio. studied da +Vinci's theory of the parachute, and found it correct, if +contemporary records and even pictorial presentment are correct. +Da Vinci showed his conception of a parachute as a sort of +inverted square bag; Veranzio modified this to a 'sort of square +sail extended by four rods of equal size and having four cords +attached at the corners,' by means of which 'a man could without +danger throw himself from the top of a tower or any high place. +For though at the moment there may be no wind, yet the effort of +his falling will carry up the wind, which the sail will hold, by +which means he does not fall suddenly but descends little by +little. The size of the sail should be measured to the man.' By +this last, evidently, Veranzio intended to convey that the sheet +must be of such content as would enclose sufficient air to +support the weight of the parachutist. + +Veranzio made his experiments about 1617-1618, but, naturally, +they carried him no farther than the mere descent to earth, and +since a descent is merely a descent, it is to be conjectured that +he soon got tired of dropping from high roofs, and took to +designing architecture instead of putting it to such a use. With +the end of his experiments the work of da Vinci in relation to +flying became neglected for nearly four centuries. + +Apart from these two experimenters, there is little to record in +the matter either of experiment or study until the seventeenth +century. Francis Bacon, it is true, wrote about flying in his +Sylva Sylvarum, and mentioned the subject in the New Atlantis, +but, except for the insight that he showed even in superficial +mention of any specific subject, he does not appear to have made +attempt at serious investigation. 'Spreading of Feathers, thin +and close and in great breadth will likewise bear up a great +Weight,' says Francis, 'being even laid without Tilting upon the +sides.' But a lesser genius could have told as much, even in +that age, and though the great Sir Francis is sometimes adduced +as one of the early students of the problems of flight, his +writings will not sustain the reputation. + +The seventeenth century, however, gives us three names, those of +Borelli, Lana, and Robert Hooke, all of which take definite +place in the history of flight. Borelli ranks as one of the +great figures in the study of aeronautical problems, in spite of +erroneous deductions through which he arrived at a purely +negative conclusion with regard to the possibility of human +flight. + +Borelli was a versatile genius. Born in 1608, he was +practically contemporary with Francesco Lana, and there is +evidence that he either knew or was in correspondence with many +prominent members of the Royal Society of Great Britain, more +especially with John Collins, Dr Wallis, and Henry Oldenburgh, +the then Secretary of the Society. He was author of a long list +of scientific essays, two of which only are responsible for his +fame, viz., Theorice Medicaearum Planetarum, published in +Florence, and the better known posthumous De Motu Animalium. The +first of these two is an astronomical study in which Borelli +gives evidence of an instinctive knowledge of gravitation, +though no definite expression is given of this. The second +work, De Motu Animalium, deals with the mechanical action of +the limbs of birds and animals and with a theory of the action +of the internal organs. A section of the first part of this +work, called De Volatu, is a study of bird flight; it is quite +independent of Da Vinci's earlier work, which had been forgotten +and remained unnoticed until near on the beginning of practical +flight. + +Marey, in his work, La Machine Animale, credits Borelli with the +first correct idea of the mechanism of flight. He says: +'Therefore we must be allowed to render to the genius of Borelli +the justice which is due to him, and only claim for ourselves +the merit of having furnished the experimental demonstration of +a truth already suspected.' In fact, all subsequent studies on +this subject concur in making Borelli the first investigator who +illustrated the purely mechanical theory of the action of a +bird's wings. + +Borelli's study is divided into a series of propositions in +which he traces the principles of flight, and the mechanical +actions of the wings of birds. The most interesting of these +are the propositions in which he sets forth the method in which +birds move their wings during flight and the manner in which the +air offers resistance to the stroke of the wing. With regard to +the first of these two points he says: 'When birds in repose +rest on the earth their wings are folded up close against their +flanks, but when wishing to start on their flight they first +bend their legs and leap into the air. Whereupon the joints of +their wings are straightened out to form a straight line at +right angles to the lateral surface of the breast, so that the +two wings, outstretched, are placed, as it were, like the arms +of a cross to the body of the bird. Next, since the wings with +their feathers attached form almost a plane surface, they are +raised slightly above the horizontal, and with a most quick +impulse beat down in a direction almost perpendicular to the +wing-plane, upon the underlying air; and to so intense a beat +the air, notwithstanding it to be fluid, offers resistance, +partly by reason of its natural inertia, which seeks to retain +it at rest, and partly because the particles of the air, +compressed by the swiftness of the stroke, resist this +compression by their elasticity, just like the hard ground. +Hence the whole mass of the bird rebounds, making a fresh leap +through the air; whence it follows that flight is simply a +motion composed of successive leaps accomplished through the +air. And I remark that a wing can easily beat the air in a +direction almost perpendicular to its plane surface, although +only a single one of the corners of the humerus bone is attached +to the scapula, the whole extent of its base remaining free and +loose, while the greater transverse feathers are joined to the +lateral skin of the thorax. Nevertheless the wing can easily +revolve about its base like unto a fan. Nor are there lacking +tendon ligaments which restrain the feathers and prevent them +from opening farther, in the same fashion that sheets hold in +the sails of ships. No less admirable is nature's cunning in +unfolding and folding the wings upwards, for she folds them not +laterally, but by moving upwards edgewise the osseous parts +wherein the roots of the feathers are inserted; for thus, +without encountering the air's resistance the upward motion of +the wing surface is made as with a sword, hence they can be +uplifted with but small force. But thereafter when the wings +are twisted by being drawn transversely and by the resistance of +the air, they are flattened as has been declared and will be +made manifest hereafter.' + +Then with reference to the resistance to the air of the wings he +explains: 'The air when struck offers resistance by its elastic +virtue through which the particles of the air compressed by the +wing-beat strive to expand again. Through these two causes of +resistance the downward beat of the wing is not only opposed, +but even caused to recoil with a reflex movement; and these two +causes of resistance ever increase the more the down stroke of +the wing is maintained and accelerated. On the other hand, the +impulse of the wing is continuously diminished and weakened by +the growing resistance. Hereby the force of the wing and the +resistance become balanced; so that, manifestly, the air is +beaten by the wing with the same force as the resistance to the +stroke.' + +He concerns himself also with the most difficult problem that +confronts the flying man of to-day, namely, landing effectively, +and his remarks on this subject would be instructive even to an +air pilot of these days: 'Now the ways and means by which the +speed is slackened at the end of a flight are these. The bird +spreads its wings and tail so that their concave surfaces are +perpendicular to the direction of motion; in this way, the +spreading feathers, like a ship's sail, strike against the still +air, check the speed, and so that most of the impetus may be +stopped, the wings are flapped quickly and strongly forward, +inducing a contrary motion, so that the bird absolutely or very +nearly stops.' + +At the end of his study Borelli came to a conclusion which +militated greatly against experiment with any heavier-than-air +apparatus, until well on into the nineteenth century, for having +gone thoroughly into the subject of bird flight he states +distinctly in his last proposition on the subject that 'It is +impossible that men should be able to fly craftily by their own +strength.' This statement, of course, remains true up to the +present day for no man has yet devised the means by which he can +raise himself in the air and maintain himself there by mere +muscular effort. + +From the time of Borelli up to the development of the steam +engine it may be said that flight by means of any +heavier-than-air apparatus was generally regarded as impossible, +and apart from certain deductions which a little experiment +would have shown to be doomed to failure, this method of flight +was not followed up. It is not to be wondered at, when +Borelli's exaggerated estimate of the strength expended by birds +in proportion to their weight is borne in mind; he alleged that +the motive force in birds' wings is 10,000 times greater than +the resistance of their weight, and with regard to human flight +he remarks:-- + +'When, therefore, it is asked whether men may be able to fly by +their own strength, it must be seen whether the motive power of +the pectoral muscles (the strength of which is indicated and +measured by their size) is proportionately great, as it is +evident that it must exceed the resistance of the weight of the +whole human body 10,000 times, together with the weight of +enormous wings which should be attached to the arms. And it is +clear that the motive power of the pectoral muscles in men is +much less than is necessary for flight, for in birds the bulk and +weight of the muscles for flapping the wings are not less than a +sixth part of the entire weight of the body. Therefore, it would +be necessary that the pectoral muscles of a man should weigh +more than a sixth part of the entire weight of his body; so also +the arms, by flapping with the wings attached, should be able to +exert a power 10,000 times greater than the weight of the human +body itself. But they are far below such excess, for the +aforesaid pectoral muscles do not equal a hundredth part of the +entire weight of a man. Wherefore either the strength of the +muscles ought to be increased or the weight of the human body +must be decreased, so that the same proportion obtains in it as +exists in birds. Hence it is deducted that the Icarian +invention is entirely mythical because impossible, for it is not +possible either to increase a man's pectoral muscles or to +diminish the weight of the human body; and whatever apparatus is +used, although it is possible to increase the momentum, the +velocity or the power employed can never equal the resistance; +and therefore wing flapping by the contraction of muscles cannot +give out enough power to carry up the heavy body of a man.' + +It may be said that practically all the conclusions which +Borelli reached in his study were negative. Although +contemporary with Lana, he perceived the one factor which +rendered Lana's project for flight by means of vacuum globes an +impossibility--he saw that no globe could be constructed +sufficiently light for flight, and at the same time sufficiently +strong to withstand the pressure of the outside atmosphere. He +does not appear to have made any experiments in flying on his +own account, having, as he asserts most definitely, no faith in +any invention designed to lift man from the surface of the +earth. But his work, from which only the foregoing short +quotations can be given, is, nevertheless, of indisputable +value, for he settled the mechanics of bird flight, and paved +the way for those later investigators who had, first, the steam +engine, and later the internal combustion engine--two factors in +mechanical flight which would have seemed as impossible to +Borelli as would wireless telegraphy to a student of Napoleonic +times. On such foundations as his age afforded Borelli built +solidly and well, so that he ranks as one of the greatest--if +not actually the greatest--of the investigators into this +subject before the age of steam. + +The conclusion, that 'the motive force in birds' wings is +apparently ten thousand times greater than the resistance of +their weight,' is erroneous, of course, but study of the +translation from which the foregoing excerpt is taken will show +that the error detracts very little from the value of the work +itself. Borelli sets out very definitely the mechanism of +flight, in such fashion that he who runs may read. His +reference to 'the use of a large vessel,' etc., concerns the +suggestion made by Francesco Lana, who antedated Borelli's +publication of De Motu Animalium by some ten years with his +suggestion for an 'aerial ship,' as he called it. Lana's mind +shows, as regards flight, a more imaginative twist; Borelli +dived down into first causes, and reached mathematical +conclusions; Lana conceived a theory and upheld it-- +theoretically, since the manner of his life precluded experiment. + +Francesco Lana, son of a noble family, was born in 1631; in 1647 +he was received as a novice into the Society of Jesus at Rome, +and remained a pious member of the Jesuit society until the end +of his life. He was greatly handicapped in his scientific +investigations by the vows of poverty which the rules of the +Order imposed on him. He was more scientist than priest all his +life; for two years he held the post of Professor of Mathematics +at Ferrara, and up to the time of his death, in 1687, he spent +by far the greater part of his time in scientific research, He +had the dubious advantage of living in an age when one man could +cover the whole range of science, and this he seems to have done +very thoroughly. There survives an immense work of his entitled, +Magisterium Naturae et Artis, which embraces the whole field of +scientific knowledge as that was developed in the period in +which Lana lived. In an earlier work of his, published in +Brescia in 1670, appears his famous treatise on the aerial ship, +a problem which Lana worked out with thoroughness. He was +unable to make practical experiments, and thus failed to +perceive the one insuperable drawback to his project--of which +more anon. + +Only extracts from the translation of Lana's work can be given +here, but sufficient can be given to show fully the means by +which he designed to achieve the conquest of the air. He begins +by mention of the celebrated pigeon of Archytas the Philosopher, +and advances one or two theories with regard to the way in which +this mechanical bird was constructed, and then he recites, +apparently with full belief in it, the fable of Regiomontanus +and the eagle that he is said to have constructed to accompany +Charles V. on his entry into Nuremberg. In fact, Lana starts +his work with a study of the pioneers of mechanical flying up to +his own time, and then outlines his own devices for the +construction of mechanical birds before proceeding to detail the +construction of the aerial ship. Concerning primary experiments +for this he says:-- + +'I will, first of all, presuppose that air has weight owing to +the vapours and halations which ascend from the earth and seas +to a height of many miles and surround the whole of our +terraqueous globe; and this fact will not be denied by +philosophers, even by those who may have but a superficial +knowledge. because it can be proven by exhausting, if not all, +at any rate the greater part of, the air contained in a glass +vessel, which, if weighed before and after the air has been +exhausted, will be found materially reduced in weight. Then I +found out how much the air weighed in itself in the following +manner. I procured a large vessel of glass, whose neck could be +closed or opened by means of a tap, and holding it open I warmed +it over a fire, so that the air inside it becoming rarified, the +major part was forced out; then quickly shutting the tap to +prevent the re-entry I weighed it; which done, I plunged its +neck in water, resting the whole of the vessel on the surface of +the water, then on opening the tap the water rose in the vessel +and filled the greater part of it. I lifted the neck out of the +water, released the water contained in the vessel, and measured +and weighed its quantity and density, by which I inferred that a +certain quantity of air had come out of the vessel equal in bulk +to the quantity of water which had entered to refill the portion +abandoned by the air. I again weighed the vessel, after I had +first of all well dried it free of all moisture, and found it +weighed one ounce more whilst it was full of air than when it +was exhausted of the greater part, so that what it weighed more +was a quantity of air equal in volume to the water which took +its place. The water weighed 640 ounces, so I concluded that +the weight of air compared with that of water was 1 to 640--that +is to say, as the water which filled the vessel weighed 640 +ounces, so the air which filled the same vessel weighed one +ounce.' + +Having thus detailed the method of exhausting air from a vessel, +Lana goes on to assume that any large vessel can be entirely +exhausted of nearly all the air contained therein. Then he +takes Euclid's proposition to the effect that the superficial +area of globes increases in the proportion of the square of the +diameter, whilst the volume increases in the proportion of the +cube of the same diameter, and he considers that if one only +constructs the globe of thin metal, of sufficient size, and +exhausts the air in the manner that he suggests, such a globe +will be so far lighter than the surrounding atmosphere that it +will not only rise, but will be capable of lifting weights. +Here is Lana's own way of putting it:-- + +'But so that it may be enabled to raise heavier weights and to +lift men in the air, let us take double the quantity of copper, +1,232 square feet, equal to 308 lbs. of copper; with this double +quantity of copper we could construct a vessel of not only +double the capacity, but of four times the capacity of the +first, for the reason shown by my fourth supposition. +Consequently the air contained in such a vessel will be 718 lbs. +4 2/3 ounces, so that if the air be drawn out of the vessel it +will be 410 lbs. 4 2/3 ounces lighter than the same volume of +air, and, consequently, will be enabled to lift three men, or at +least two, should they weigh more than eight pesi each. It is +thus manifest that the larger the ball or vessel is made, the +thicker and more solid can the sheets of copper be made, because, +although the weight will increase, the capacity of the vessel +will increase to a greater extent and with it the weight of the +air therein, so that it will always be capable to lift a heavier +weight. From this it can be easily seen how it is possible to +construct a machine which, fashioned like unto a ship, will float +on the air.' + +With four globes of these dimensions Lana proposed to make an +aerial ship of the fashion shown in his quaint illustration. He +is careful to point out a method by which the supporting globes +for the aerial ship may be entirely emptied of air; this is to +be done by connecting to each globe a tube of copper which is +'at least a length of 47 modern Roman palm).' A small tap is to +close this tube at the end nearest the globe, and then vessel +and tube are to be filled with water, after which the tube is to +be immersed in water and the tap opened, allowing the water to +run out of the vessel, while no air enters. The tap is then +closed before the lower end of the tube is removed from the +water, leaving no air at all in the globe or sphere. Propulsion +of this airship was to be accomplished by means of sails, and +also by oars. + +Lana antedated the modern propeller, and realised that the air +would offer enough resistance to oars or paddle to impart motion +to any vessel floating in it and propelled by these means, +although he did not realise the amount of pressure on the air +which would be necessary to accomplish propulsion. As a matter +of fact, he foresaw and provided against practically all the +difficulties that would be encountered in the working, as well +as the making, of the aerial ship, finally coming up against +what his religious training made an insuperable objection. +This, again, is best told in his own words:-- + +'Other difficulties I do not foresee that could prevail against +this invention, save one only, which to me seems the greatest of +them all, and that is that God would surely never allow such a +machine to be successful, since it would create many +disturbances in the civil and political governments of mankind.' + +He ends by saying that no city would be proof against surprise, +while the aerial ship could set fire to vessels at sea, and +destroy houses, fortresses, and cities by fire balls and bombs. +In fact, at the end of his treatise on the subject, he furnishes +a pretty complete resume of the activities of German Zeppelins. + +As already noted, Lana himself, owing to his vows of poverty, +was unable to do more than put his suggestions on paper, which +he did with a thoroughness that has procured him a place among +the really great pioneers of flying. + +It was nearly 200 years before any attempt was made to realise +his project; then, in 1843, M. Marey Monge set out to make the +globes and the ship as Lana detailed them. Monge's experiments +cost him the sum of 25,000 francs 75 centimes, which he expended +purely from love of scientific investigation. He chose to make +his globes of brass, about .004 in thickness, and weighing 1.465 +lbs. to the square yard. Having made his sphere of this metal, +he lined it with two thicknesses of tissue paper, varnished it +with oil, and set to work to empty it of air. This, however, he +never achieved, for such metal is incapable of sustaining the +pressure of the outside air, as Lana, had he had the means to +carry out experiments, would have ascertained. M. Monge's +sphere could never be emptied of air sufficiently to rise from +the earth; it ended in the melting-pot, ignominiously enough, +and all that Monge got from his experiment was the value of the +scrap metal and the satisfaction of knowing that Lana's theory +could never be translated into practice. + +Robert Hooke is less conspicuous than either Borelli or Lana; +his work, which came into the middle of the seventeenth century, +consisted of various experiments with regard to flight, from +which emerged 'a Module, which by the help of Springs and Wings, +raised and sustained itself in the air.' This must be reckoned +as the first model flying machine which actually flew, except +for da Vinci's helicopters; Hooke's model appears to have been +of the flapping-wing type--he attempted to copy the motion of +birds, but found from study and experiment that human muscles +were not sufficient to the task of lifting the human body. For +that reason, he says, 'I applied my mind to contrive a way to +make artificial muscles,' but in this he was, as he expresses +it, 'frustrated of my expectations.' Hooke's claim to fame +rests mainly on his successful model; the rest of his work is of +too scrappy a nature to rank as a serious contribution to the +study of flight. + +Contemporary with Hooke was one Allard, who, in France, +undertook to emulate the Saracen of Constantinople to a certain +extent. Allard was a tight-rope dancer who either did or was +said to have done short gliding flights--the matter is open to +question--and finally stated that he would, at St Germains, fly +from the terrace in the king's presence. He made the attempt, +but merely fell, as did the Saracen some centuries before, +causing himself serious injury. Allard cannot be regarded as a +contributor to the development of aeronautics in any way, and is +only mentioned as typical of the way in which, up to the time of +the Wright brothers, flying was regarded. Even unto this day +there are many who still believe that, with a pair of wings, man +ought to be able to fly, and that the mathematical data +necessary to effective construction simply do not exist. This +attitude was reasonable enough in an unlearned age, and Allard +was one--a little more conspicuous than the majority--among many +who made experiment in ignorance, with more or less danger to +themselves and without practical result of any kind. + +The seventeenth century was not to end, however, without +practical experiment of a noteworthy kind in gliding flight. +Among the recruits to the ranks of pioneers was a certain +Besnier, a locksmith of Sable, who somewhere between 1675 and +1680 constructed a glider of which a crude picture has come down +to modern times. The apparatus, as will be seen, consisted of +two rods with hinged flaps, and the original designer of the +picture seems to have had but a small space in which to draw, +since obviously the flaps must have been much larger than those +shown. Besnier placed the rods on his shoulders, and worked the +flaps by cords attached to his hands and feet--the flaps opened +as they fell, and closed as they rose, so the device as a whole +must be regarded as a sort of flapping glider. Having by +experiment proved his apparatus successful, Besnier promptly +sold it to a travelling showman of the period, and forthwith set +about constructing a second set, with which he made gliding +flights of considerable height and distance. Like Lilienthal, +Besnier projected himself into space from some height, and then, +according to the contemporary records, he was able to cross a +river of considerable size before coming to earth. It does not +appear that he had any imitators, or that any advantage whatever +was taken of his experiments; the age was one in which he would +be regarded rather as a freak exhibitor than as a serious +student, and possibly, considering his origin and the sale of +his first apparatus to such a client, he regarded the matter +himself as more in the nature of an amusement than as a +discovery. + +Borelli, coming at the end of the century, proved to his own +satisfaction and that of his fellows that flapping wing flight +was an impossibility; the capabilities of the plane were as yet +undreamed, and the prime mover that should make the plane +available for flight was deep in the womb of time. Da Vinci's +work was forgotten--flight was an impossibility, or at best such +a useless show as Besnier was able to give. + +The eighteenth century was almost barren of experiment. Emanuel +Swedenborg, having invented a new religion, set about inventing +a flying machine, and succeeded theoretically, publishing the +result of his investigations as follows:-- + +'Let a car or boat or some like object be made of light material +such as cork or bark, with a room within it for the operator. +Secondly, in front as well as behind, or all round, set a +widely-stretched sail parallel to the machine forming within a +hollow or bend which could be reefed like the sails of a ship. +Thirdly, place wings on the sides, to be worked up and down by a +spiral spring, these wings also to be hollow below in order to +increase the force and velocity, take in the air, and make the +resistance as great as may be required. These, too, should be +of light material and of sufficient size; they should be in the +shape of birds' wings, or the sails of a windmill, or some such +shape, and should be tilted obliquely upwards, and made so as to +collapse on the upward stroke and expand on the downward. +Fourth, place a balance or beam below, hanging down +perpendicularly for some distance with a small weight attached +to its end, pendent exactly in line with the centre of gravity; +the longer this beam is, the lighter must it be, for it must +have the same proportion as the well-known vectis or steel-yard. +This would serve to restore the balance of the machine if it +should lean over to any of the four sides. Fifthly, the wings +would perhaps have greater force, so as to increase the +resistance and make the flight easier, if a hood or shield were +placed over them, as is the case with certain insects. Sixthly, +when the sails are expanded so as to occupy a great surface and +much air, with a balance keeping them horizontal, only a small +force would be needed to move the machine back and forth in a +circle, and up and down. And, after it has gained momentum to +move slowly upwards, a slight movement and an even bearing would +keep it balanced in the air and would determine its direction at +will.' + +The only point in this worthy of any note is the first device +for maintaining stability automatically--Swedenborg certainly +scored a point there. For the rest. his theory was but theory, +incapable of being put to practice--he does not appear to have +made any attempt at advance beyond the mere suggestion. + +Some ten years before his time the state of knowledge with +regard to flying in Europe was demonstrated by an order granted +by the King of Portugal to Friar Lourenzo de Guzman, who claimed +to have invented a flying machine capable of actual flight. The +order stated that 'In order to encourage the suppliant to apply +himself with zeal toward the improvement of the new machine, +which is capable of producing the effects mentioned by him, I +grant unto him the first vacant place in my College of Barcelos +or Santarem, and the first professorship of mathematics in my +University of Coimbra, with the annual pension of 600,000 reis +during his life.--Lisbon, 17th of March, 1709.' + +What happened to Guzman when the non-existence of the machine +was discovered is one of the things that is well outside the +province of aeronautics. He was charlatan pure and simple, as +far as actual flight was concerned, though he had some ideas +respecting the design of hot-air balloons, according to +Tissandier. (La Navigation Aerienne.) His flying machine was to +contain, among other devices, bellows to produce artificial wind +when the real article failed, and also magnets in globes to draw +the vessel in an upward direction and maintain its buoyancy. +Some draughtsman, apparently gifted with as vivid imagination as +Guzman himself, has given to the world an illustration of the +hypothetical vessel; it bears some resemblance to Lana's aerial +ship, from which fact one draws obvious conclusions. + +A rather amusing claim to solving the problem of flight was +made in the middle of the eighteenth century by one Grimaldi, a +'famous and unique Engineer' who, as a matter of actual fact, +spent twenty years in missionary work in India, and employed the +spare time that missionary work left him in bringing his +invention to a workable state. The invention is described as a +'box which with the aid of clockwork rises in the air, and goes +with such lightness and strong rapidity that it succeeds in +flying a journey of seven leagues in an hour. It is made in the +fashion of a bird; the wings from end to end are 25 feet in +extent. The body is composed of cork, artistically joined +together and well fastened with metal wire, covered with +parchment and feathers. The wings are made of catgut and +whalebone, and covered also with the same parchment and +feathers, and each wing is folded in three seams. In the body +of the machine are contained thirty wheels of unique work, with +two brass globes and little chains which alternately wind up a +counterpoise; with the aid of six brass vases, full of a certain +quantity of quicksilver, which run in some pulleys, the machine +is kept by the artist in due equilibrium and balance. By means, +then, of the friction between a steel wheel adequately tempered +and a very heavy and surprising piece of lodestone, the whole is +kept in a regulated forward movement, given, however, a right +state of the winds, since the machine cannot fly so much in +totally calm weather as in stormy. This prodigious machine is +directed and guided by a tail seven palmi long, which is +attached to the knees and ankles of the inventor by leather +straps; by stretching out his legs, either to the right or to +the left, he moves the machine in whichever direction he +pleases.... The machine's flight lasts only three hours, after +which the wings gradually close themselves, when the inventor, +perceiving this, goes down gently, so as to get on his own feet, +and then winds up the clockwork and gets himself ready again +upon the wings for the continuation of a new flight. He himself +told us that if by chance one of the wheels came off or if one +of the wings broke, it is certain he would inevitably fall +rapidly to the ground, and, therefore, he does not rise more +than the height of a tree or two, as also he only once put +himself in the risk of crossing the sea, and that was from +Calais to Dover, and the same morning he arrived in London.' + +And yet there are still quite a number of people who persist in +stating that Bleriot was the first man to fly across the +Channel! + +A study of the development of the helicopter principle was +published in France in 1868, when the great French engineer +Paucton produced his Theorie de la Vis d'Archimede. For some +inexplicable reason, Paucton was not satisfied with the term +'helicopter,' but preferred to call it a 'pterophore,' a name +which, so far as can be ascertained, has not been adopted by any +other writer or investigator. Paucton stated that, since a man +is capable of sufficient force to overcome the weight of his own +body, it is only necessary to give him a machine which acts on +the air 'with all the force of which it is capable and at its +utmost speed,' and he will then be able to lift himself in the +air, just as by the exertion of all his strength he is able to +lift himself in water. 'It would seem,' says Paucton, 'that in +the pterophore, attached vertically to a carriage, the whole +built lightly and carefully assembled, he has found something +that will give him this result in all perfection. In +construction, one would be careful that the machine produced the +least friction possible, and naturally it ought to produce +little, as it would not be at all complicated. The new +Daedalus, sitting comfortably in his carriage, would by means of +a crank give to the pterophore a suitable circular (or +revolving) speed. This single pterophore would lift him +vertically, but in order to move horizontally he should be +supplied with a tail in the shape of another pterophore. When +he wished to stop for a little time, valves fixed firmly across +the end of the space between the blades would automatically +close the openings through which the air flows, and change the +pterophore into an unbroken surface which would resist the flow +of air and retard the fall of the machine to a considerable +degree.' + +The doctrine thus set forth might appear plausible, but it is +based on the common misconception that all the force which might +be put into the helicopter or 'pterophore' would be utilised for +lifting or propelling the vehicle through the air, just as a +propeller uses all its power to drive a ship through water. +But, in applying such a propelling force to the air, most of the +force is utilised in maintaining aerodynamic support--as a +matter of fact, more force is needed to maintain this support +than the muscle of man could possibly furnish to a lifting +screw, and even if the helicopter were applied to a full-sized, +engine-driven air vehicle, the rate of ascent would depend on +the amount of surplus power that could be carried. For example, +an upward lift of 1,000 pounds from a propeller 15 feet in +diameter would demand an expenditure of 50 horse-power under the +best possible conditions, and in order to lift this load +vertically through such atmospheric pressure as exists at +sea-level or thereabouts, an additional 20 horsepower would be +required to attain a rate of 11 feet per second--50 horse-power +must be continually provided for the mere support of the load, +and the additional 20 horse-power must be continually provided +in order to lift it. Although, in model form, there is nothing +quite so strikingly successful as the helicopter in the range of +flying machines, yet the essential weight increases so +disproportionately to the effective area that it is necessary to +go but very little beyond model dimensions for the helicopter to +become quite ineffective. + +That is not to say that the lifting screw must be totally ruled +out so far as the construction of aircraft is concerned. Much +is still empirical, so far as this branch of aeronautics is +concerned, and consideration of the structural features of a +propeller goes to show that the relations of essential weight +and effective area do not altogether apply in practice as they +stand in theory. Paucton's dream, in some modified form, may yet +become reality--it is only so short a time ago as 1896 that Lord +Kelvin stated he had not the smallest molecule of faith in +aerial navigation, and since the whole history of flight +consists in proving the impossible possible, the helicopter may +yet challenge the propelled plane surface for aerial supremacy. + +It does not appear that Paucton went beyond theory, nor is there +in his theory any advance toward practical flight--da Vinci +could have told him as much as he knew. He was followed by +Meerwein, who invented an apparatus apparently something between +a flapping wing machine and a glider, consisting of two wings, +which were to be operated by means of a rod; the venturesome one +who would fly by means of this apparatus had to lie in a +horizontal position beneath the wings to work the rod. Meerwein +deserves a place of mention, however, by reason of his +investigations into the amount of surface necessary to support a +given weight. Taking that weight at 200 pounds--which would +allow for the weight of a man and a very light apparatus--he +estimated that 126 square feet would be necessary for support. +His pamphlet, published at Basle in 1784, shows him to have been +a painstaking student of the potentialities of flight. + +Jean-Pierre Blanchard, later to acquire fame in connection with +balloon flight, conceived and described a curious vehicle, of +which he even announced trials as impending. His trials were +postponed time after time, and it appears that he became +convinced in the end of the futility of his device, being +assisted to such a conclusion by Lalande, the astronomer, who +repeated Borelli's statement that it was impossible for man ever +to fly by his own strength. This was in the closing days of the +French monarchy, and the ascent of the Montgolfiers' first +hot-air balloon in 1783--which shall be told more fully in its +place--put an end to all French experiments with heavier- +than-air apparatus, though in England the genius of Cayley was +about to bud, and even in France there were those who understood +that ballooning was not true flight. + + + +III. SIR GEORGE CAYLEY--THOMAS WALKER + +On the fifth of June, 1783, the Montgolfiers' hot-air balloon +rose at Versailles, and in its rising divided the study of the +conquest of the air into two definite parts, the one being +concerned with the propulsion of gas lifted, lighter-than-air +vehicles, and the other being crystallised in one sentence by +Sir George Cayley: 'The whole problem,' he stated, 'is +confined within these limits, viz.: to make a surface support a +given weight by the application of power to the resistance of +the air.' For about ten years the balloon held the field +entirely, being regarded as the only solution of the problem of +flight that man could ever compass. So definite for a time was +this view on the eastern side of the Channel that for some years +practically all the progress that was made in the development of +power-driven planes was made in Britain. + +In 1800 a certain Dr Thomas Young demonstrated that certain +curved surfaces suspended by a thread moved into and not away +from a horizontal current of air, but the demonstration, which +approaches perilously near to perpetual motion if the current be +truly horizontal, has never been successfully repeated, so that +there is more than a suspicion that Young's air-current was NOT +horizontal. Others had made and were making experiments on the +resistance offered to the air by flat surfaces, when Cayley came +to study and record, earning such a place among the pioneers as +to win the title of 'father of British aeronautics.' + +Cayley was a man in advance of his time, in many ways. Of +independent means, he made the grand tour which was considered +necessary to the education of every young man of position, and +during this excursion he was more engaged in studies of a +semi-scientific character than in the pursuits that normally +filled such a period. His various writings prove that +throughout his life aeronautics was the foremost subject in his +mind; the Mechanic's Magazine, Nicholson's Journal, the +Philosophical Magazine, and other periodicals of like nature +bear witness to Cayley's continued research into the subject of +flight. He approached the subject after the manner of the +trained scientist, analysing the mechanical properties of air +under chemical and physical action. Then he set to work to +ascertain the power necessary for aerial flight, and was one of +the first to enunciate the fallacy of the hopes of successful +flight by means of the steam engine of those days, owing to the +fact that it was impossible to obtain a given power with a given +weight. + +Yet his conclusions on this point were not altogether negative, +for as early as 1810 he stated that he could construct a balloon +which could travel with passengers at 20 miles an hour--he was +one of the first to consider the possibilities of applying power +to a balloon. Nearly thirty years later--in 1837--he made the +first attempt at establishing an aeronautical society, but at +that time the power-driven plane was regarded by the great +majority as an absurd dream of more or less mad inventors, while +ballooning ranked on about the same level as tight-rope walking, +being considered an adjunct to fairs and fetes, more a pastime +than a study. + +Up to the time of his death, in 1857, Cayley maintained his +study of aeronautical matters, and there is no doubt whatever +that his work went far in assisting the solution of the problem +of air conquest. His principal published work, a monograph +entitled Aerial Navigation, has been republished in the +admirable series of 'Aeronautical Classics' issued by the Royal +Aeronautical Society. He began this work by pointing out the +impossibility of flying by means of attached wings, an +impossibility due to the fact that, while the pectoral muscles +of a bird account for more than two-thirds of its whole muscular +strength, in a man the muscles available for flying, no matter +what mechanism might be used, would not exceed one-tenth of his +total strength. + +Cayley did not actually deny the possibility of a man flying by +muscular effort, however, but stated that 'the flight of a +strong man by great muscular exertion, though a curious and +interesting circumstance, inasmuch as it will probably be the +means of ascertaining finis power and supplying the basis +whereon to improve it, would be of little use.' + +From this he goes on to the possibility of using a Boulton and +Watt steam engine to develop the power necessary for flight, and +in this he saw a possibility of practical result. It is worthy +of note that in this connection he made mention of the +forerunner of the modern internal combustion engine; 'The +French,' he said, 'have lately shown the great power produced by +igniting inflammable powders in closed vessels, and several +years ago an engine was made to work in this country in a +similar manner by inflammation of spirit of tar.' In a +subsequent paragraph of his monograph he anticipates almost +exactly the construction of the Lenoir gas engine, which came +into being more than fifty-five years after his monograph was +published. + +Certain experiments detailed in his work were made to ascertain +the size of the surface necessary for the support of any given +weight. He accepted a truism of to-day in pointing out that in +any matters connected with aerial investigation, theory and +practice are as widely apart as the poles. Inclined at first to +favour the helicopter principle, he finally rejected this in +favour of the plane, with which he made numerous experiments. +During these, he ascertained the peculiar advantages of curved +surfaces, and saw the necessity of providing both vertical and +horizontal rudders in order to admit of side steering as well as +the control of ascent and descent, and for preserving +equilibrium. He may be said to have anticipated the work of +Lilienthal and Pilcher, since he constructed and experimented +with a fixed surface glider. 'It was beautiful,' he wrote +concerning this, 'to see this noble white bird sailing +majestically from the top of a hill to any given point of the +plain below it with perfect steadiness and safety, according to +the set of its rudder, merely by its own weight, descending at +an angle of about eight degrees with the horizon.' + +It is said that he once persuaded his gardener to trust himself +in this glider for a flight, but if Cayley himself ventured a +flight in it he has left no record of the fact. The following +extract from his work, Aerial Navigation, affords an instance of +the thoroughness of his investigations, and the concluding +paragraph also shows his faith in the ultimate triumph of +mankind in the matter of aerial flight:-- + +'The act of flying requires less exertion than from the +appearance is supposed. Not having sufficient data to ascertain +the exact degree of propelling power exerted by birds in the act +of flying, it is uncertain what degree of energy may be required +in this respect for vessels of aerial navigation; yet when we +consider the many hundreds of miles of continued flight exerted +by birds of passage, the idea of its being only a small effort +is greatly corroborated. To apply the power of the first mover +to the greatest advantage in producing this effect is a very +material point. The mode universally adopted by Nature is the +oblique waft of the wing. We have only to choose between the +direct beat overtaking the velocity of the current, like the oar +of a boat, or one applied like the wing, in some assigned degree +of obliquity to it. Suppose 35 feet per second to be the +velocity of an aerial vehicle, the oar must be moved with this +speed previous to its being able to receive any resistance; then +if it be only required to obtain a pressure of one-tenth of a +lb. upon each square foot it must exceed the velocity of the +current 7.3 feet per second. Hence its whole velocity must be +42.5 feet per second. Should the same surface be wafted +downward like a wing with the hinder edge inclined upward in an +angle of about 50 deg. 40 feet to the current it will overtake +it at a velocity of 3.5 feet per second; and as a slight unknown +angle of resistance generates a lb. pressure per square foot at +this velocity, probably a waft of a little more than 4 feet per +second would produce this effect, one-tenth part of which would +be the propelling power. The advantage of this mode of +application compared with the former is rather more than ten to +one. + +'In continuing the general principles of aerial navigation, for +the practice of the art, many mechanical difficulties present +themselves which require a considerable course of skilfully +applied experiments before they can be overcome; but, to a +certain extent, the air has already been made navigable, and no +one who has seen the steadiness with which weights to the amount +of ten stone (including four stone, the weight of the machine) +hover in the air can doubt of the ultimate accomplishment of +this object.' + +This extract from his work gives but a faint idea of the amount +of research for which Cayley was responsible. He had the +humility of the true investigator in scientific problems, and so +far as can be seen was never guilty of the great fault of so +many investigators in this subject--that of making claims which +he could not support. He was content to do, and pass after +having recorded his part, and although nearly half a century had +to pass between the time of his death and the first actual +flight by means of power-driven planes, yet he may be said to +have contributed very largely to the solution of the problem, +and his name will always rank high in the roll of the pioneers +of flight. + +Practically contemporary with Cayley was Thomas Walker, +concerning whom little is known save that he was a portrait +painter of Hull, where was published his pamphlet on The Art of +Flying in 1810, a second and amplified edition being produced, +also in Hull, in 1831. The pamphlet, which has been reproduced +in extenso in the Aeronautical Classics series published by the +Royal Aeronautical Society, displays a curious mixture of the +true scientific spirit and colossal conceit. Walker appears to +have been a man inclined to jump to conclusions, which carried +him up to the edge of discovery and left him vacillating there. + +The study of the two editions of his pamphlet side by side shows +that their author made considerable advances in the +practicability of his designs in the 21 intervening years, +though the drawings which accompany the text in both editions +fail to show anything really capable of flight. The great point +about Walker's work as a whole is its suggestiveness; he did not +hesitate to state that the 'art' of flying is as truly +mechanical as that of rowing a boat, and he had some conception +of the necessary mechanism, together with an absolute conviction +that he knew all there was to be known. 'Encouraged by the +public,' he says, 'I would not abandon my purpose of making +still further exertions to advance and complete an art, the +discovery of the TRUE PRINCIPLES (the italics are Walker's own) +of which, I trust, I can with certainty affirm to be my own.' + +The pamphlet begins with Walker's admiration of the mechanism of +flight as displayed by birds. 'It is now almost twenty years,' +he says, 'since I was first led to think, by the study of birds +and their means of flying, that if an artificial machine were +formed with wings in exact imitation of the mechanism of one of +those beautiful living machines, and applied in the very same +way upon the air, there could be no doubt of its being made to +fly, for it is an axiom in philosophy that the same cause will +ever produce the same effect.' With this he confesses his +inability to produce the said effect through lack of funds, +though he clothes this delicately in the phrase 'professional +avocations and other circumstances.' Owing to this inability he +published his designs that others might take advantage of them, +prefacing his own researches with a list of the very early +pioneers, and giving special mention to Friar Bacon, Bishop +Wilkins, and the Portuguese friar, De Guzman. But, although he +seems to suggest that others should avail themselves of his +theoretical knowledge, there is a curious incompleteness about +the designs accompanying his work, and about the work itself, +which seems to suggest that he had more knowledge to impart than +he chose to make public--or else that he came very near to +complete solution of the problem of flight, and stayed on the +threshold without knowing it. + +After a dissertation upon the history and strength of the +condor, and on the differences between the weights of birds, he +says: 'The following observations upon the wonderful difference +in the weight of some birds, with their apparent means of +supporting it in their flight, may tend to remove some +prejudices against my plan from the minds of some of my readers. +The weight of the humming-bird is one drachm, that of the condor +not less than four stone. Now, if we reduce four stone into +drachms we shall find the condor is 14,336 times as heavy as the +humming-bird. What an amazing disproportion of weight! Yet by +the same mechanical use of its wings the condor can overcome the +specific gravity of its body with as much ease as the little +humming-bird. But this is not all. We are informed that this +enormous bird possesses a power in its wings, so far exceeding +what is necessary for its own conveyance through the air, that +it can take up and fly away with a whole sheer in its talons, +with as much ease as an eagle would carry off, in the same +manner, a hare or a rabbit. This we may readily give credit to, +from the known fact of our little kestrel and the sparrow-hawk +frequently flying off with a partridge, which is nearly three +times the weight of these rapacious little birds.' + +After a few more observations he arrives at the following +conclusion: 'By attending to the progressive increase in the +weight of birds, from the delicate little humming-bird up to the +huge condor, we clearly discover that the addition of a few +ounces, pounds, or stones, is no obstacle to the art of flying; +the specific weight of birds avails nothing, for by their +possessing wings large enough, and sufficient power to work +them, they can accomplish the means of flying equally well upon +all the various scales and dimensions which we see in nature. +Such being a fact, in the name of reason and philosophy why +shall not man, with a pair of artificial wings, large enough, +and with sufficient power to strike them upon the air, be able +to produce the same effect?' + +Walker asserted definitely and with good ground that muscular +effort applied without mechanism is insufficient for human +flight, but he states that if an aeronautical boat were +constructed so that a man could sit in it in the same manner as +when rowing, such a man would be able to bring into play his +whole bodily strength for the purpose of flight, and at the same +time would be able to get an additional advantage by exerting +his strength upon a lever. At first he concluded there must be +expansion of wings large enough to resist in a sufficient degree +the specific gravity of whatever is attached to them, but in the +second edition of his work he altered this to 'expansion of flat +passive surfaces large enough to reduce the force of gravity so +as to float the machine upon the air with the man in it.' The +second requisite is strength enough to strike the wings with +sufficient force to complete the buoyancy and give a projectile +motion to the machine. Given these two requisites, Walker states +definitely that flying must be accomplished simply by muscular +exertion. 'If we are secure of these two requisites, and I am +very confident we are, we may calculate upon the success of +flight with as much certainty as upon our walking.' + +Walker appears to have gained some confidence from the +experiments of a certain M. Degen, a watchmaker of Vienna, who, +according to the Monthly Magazine of September, 1809, invented a +machine by means of which a person might raise himself into the +air. The said machine, according to the magazine, was formed of +two parachutes which might be folded up or extended at pleasure, +while the person who worked them was placed in the centre. This +account, however, was rather misleading, for the magazine +carefully avoided mention of a balloon to which the inventor +fixed his wings or parachutes. Walker, knowing nothing of the +balloon, concluded that Degen actually raised himself in the air, +though he is doubtful of the assertion that Degen managed to fly +in various directions, especially against the wind. + +Walker, after considering Degen and all his works, proceeds to +detail his own directions for the construction of a flying +machine, these being as follows: 'Make a car of as light +material as possible, but with sufficient strength to support a +man in it; provide a pair of wings about four feet each in +length; let them be horizontally expanded and fastened upon the +top edge of each side of the car, with two joints each, so as to +admit of a vertical motion to the wings, which motion may be +effected by a man sitting and working an upright lever in the +middle of the car. Extend in the front of the car a flat surface +of silk, which must be stretched out and kept fixed in a passive +state; there must be the same fixed behind the car; these two +surfaces must be perfectly equal in length and breadth and large +enough to cover a sufficient quantity of air to support the whole +weight as nearly in equilibrium as possible, thus we shall have a +great sustaining power in those passive surfaces and the active +wings will propel the car forward.' + +A description of how to launch this car is subsequently given: +'It becomes necessary,' says the theorist, 'that I should give +directions how it may be launched upon the air, which may be done +by various means; perhaps the following method may be found to +answer as well as any: Fix a poll upright in the earth, about +twenty feet in height, with two open collars to admit another +poll to slide upwards through them; let there be a sliding +platform made fast upon the top of the sliding poll; place the +car with a man in it upon the platform, then raise the platform +to the height of about thirty feet by means of the sliding poll, +let the sliding poll and platform suddenly fall down, the car +will then be left upon the air, and by its pressing the air a +projectile force will instantly propel the car forward; the man +in the car must then strike the active wings briskly upon the +air, which will so increase the projectile force as to become +superior to the force of gravitation, and if he inclines his +weight a little backward, the projectile impulse will drive the +car forward in an ascending direction. When the car is brought to +a sufficient altitude to clear the tops of hills, trees, +buildings, etc., the man, by sitting a little forward on his +seat, will then bring the wings upon a horizontal plane, and by +continuing the action of the wings he will be impelled forward +in that direction. To descend, he must desist from striking the +wings, and hold them on a level with their joints; the car will +then gradually come down, and when it is within five or six feet +of the ground the man must instantly strike the wings downwards, +and sit as far back as he can; he will by this means check the +projectile force, and cause the car to alight very gently with a +retrograde motion. The car, when up in the air, may be made to +turn to the right or to the left by forcing out one of the fins, +having one about eighteen inches long placed vertically on each +side of the car for that purpose, or perhaps merely by the man +inclining the weight of his body to one side.' + +Having stated how the thing is to be done, Walker is careful to +explain that when it is done there will be in it some practical +use, notably in respect of the conveyance of mails and +newspapers, or the saving of life at sea, or for exploration, +etc. It might even reduce the number of horses kept by man for +his use, by means of which a large amount of land might be set +free for the growth of food for human consumption. + +At the end of his work Walker admits the idea of steam power for +driving a flying machine in place of simple human exertion, but +he, like Cayley, saw a drawback to this in the weight of the +necessary engine. On the whole, he concluded, navigation of the +air by means of engine power would be mostly confined to the +construction of navigable balloons. + +As already noted, Walker's work is not over practical, and the +foregoing extract includes the most practical part of it; the +rest is a series of dissertations on bird flight, in which, +evidently, the portrait painter's observations were far less +thorough than those of da Vinci or Borelli. Taken on the whole, +Walker was a man with a hobby; he devoted to it much time and +thought, but it remained a hobby, nevertheless. His +observations have proved useful enough to give him a place among +the early students of flight, but a great drawback to his work +is the lack of practical experiment, by means of which alone +real advance could be made; for, as Cayley admitted, theory and +practice are very widely separated in the study of aviation, and +the whole history of flight is a matter of unexpected results +arising from scarcely foreseen causes, together with experiment +as patient as daring. + + + +IV. THE MIDDLE NINETEENTH CENTURY + +Both Cayley and Walker were theorists, though Cayley supported +his theoretical work with enough of practice to show that he +studied along right lines; a little after his time there came +practical men who brought to being the first machine which +actually flew by the application of power. Before their time, +however, mention must be made of the work of George Pocock of +Bristol, who, somewhere about 1840 invented what was described +as a 'kite carriage,' a vehicle which carried a number of +persons, and obtained its motive power from a large kite. It is +on record that, in the year 1846 one of these carriages conveyed +sixteen people from Bristol to London. Another device of +Pocock's was what he called a 'buoyant sail,' which was in +effect a man-lifting kite, and by means of which a passenger was +actually raised 100 yards from the ground, while the inventor's +son scaled a cliff 200 feet in height by means of one of these, +'buoyant sails.' This constitutes the first definitely recorded +experiment in the use of man-lifting kites. A History of the +Charvolant or Kite-carriage, published in London in 1851, states +that 'an experiment of a bold and very novel character was made +upon an extensive down, where a large wagon with a considerable +load was drawn along, whilst this huge machine at the same time +carried an observer aloft in the air, realising almost the +romance of flying.' + +Experimenting, two years after the appearance of the +'kite-carriage,' on the helicopter principle, W. H. Phillips +constructed a model machine which weighed two pounds; this was +fitted with revolving fans, driven by the combustion of +charcoal, nitre, and gypsum, producing steam which, discharging +into the air, caused the fans to revolve. The inventor stated +that 'all being arranged, the steam was up in a few seconds, +when the whole apparatus spun around like any top, and mounted +into the air faster than a bird; to what height it ascended I +had no means of ascertaining; the distance travelled was across +two fields, where, after a long search, I found the machine +minus the wings, which had been torn off in contact with the +ground.' This could hardly be described as successful flight, +but it was an advance in the construction of machines on the +helicopter principle, and it was the first steam-driven model of +the type which actually flew. The invention, however, was not +followed up. + +After Phillips, we come to the great figures of the middle +nineteenth century, W. S. Henson and John Stringfellow. Cayley +had shown, in 1809, how success might be attained by developing +the idea of the plane surface so driven as to take advantage of +the resistance offered by the air, and Henson, who as early as +1840 was experimenting with model gliders and light steam +engines, evolved and patented an idea for something very nearly +resembling the monoplane of the early twentieth century. His +patent, No. 9478, of the year 1842 explains the principle of the +machine as follows:-- + +In order that the description hereafter given be rendered clear, +I will first shortly explain the principle on which the machine +is constructed. If any light and flat or nearly flat article be +projected or thrown edgewise in a slightly inclined position, +the same will rise on the air till the force exerted is +expended, when the article so thrown or projected will descend; +and it will readily be conceived that, if the article so +projected or thrown possessed in itself a continuous power or +force equal to that used in throwing or projecting it, the +article would continue to ascend so long as the forward part of +the surface was upwards in respect to the hinder part, and that +such article, when the power was stopped, or when the +inclination was reversed, would descend by gravity aided by the +force of the power contained in the article, if the power be +continued, thus imitating the flight of a bird. + +Now, the first part of my invention consists of an apparatus so +constructed as to offer a very extended surface or plane of a +light yet strong construction, which will have the same relation +to the general machine which the extended wings of a bird have +to the body when a bird is skimming in the air; but in place of +the movement or power for onward progress being obtained by +movement of the extended surface or plane, as is the case with +the wings of birds, I apply suitable paddle-wheels or other +proper mechanical propellers worked by a steam or other +sufficiently light engine, and thus obtain the requisite power +for onward movement to the plane or extended surface; and in +order to give control as to the upward and downward direction of +such a machine I apply a tail to the extended surface which is +capable of being inclined or raised, so that when the power is +acting to propel the machine, by inclining the tail upwards, +the resistance offered by the air will cause the machine to rise +on the air; and, on the contrary, when the inclination of the +tail is reversed, the machine will immediately be propelled +downwards, and pass through a plane more or less inclined to the +horizon as the inclination of the tail is greater or less; and +in order to guide the machine as to the lateral direction which +it shall take, I apply a vertical rudder or second tail, and, +according as the same is inclined in one direction or the other, +so will be the direction of the machine.' + +The machine in question was very large, and differed very little +from the modern monoplane; the materials were to be spars of +bamboo and hollow wood, with diagonal wire bracing. The surface +of the planes was to amount to 4,500 square feet, and the tail, +triangular in form (here modern practice diverges) was to be +1,500 square feet. The inventor estimated that there would be a +sustaining power of half a pound per square foot, and the +driving power was to be supplied by a steam engine of 25 to 30 +horse-power, driving two six-bladed propellers. Henson was +largely dependent on Stringfellow for many details of his +design, more especially with regard to the construction of the +engine. + +The publication of the patent attracted a great amount of public +attention, and the illustrations in contemporary journals, +representing the machine flying over the pyramids and the +Channel, anticipated fact by sixty years and more; the +scientific world was divided, as it was up to the actual +accomplishment of flight, as to the value of the invention. + +Strongfellow and Henson became associated after the conception +of their design, with an attorney named Colombine, and a Mr +Marriott, and between the four of them a project grew for +putting the whole thing on a commercial basis--Henson and +Stringfellow were to supply the idea; Marriott, knowing a member +of Parliament, would be useful in getting a company +incorporated, and Colombine would look after the purely legal +side of the business. Thus an application was made by Mr +Roebuck, Marriott's M.P., for an act of incorporation for 'The +Aerial Steam Transit Company,' Roebuck moving to bring in the +bill on the 24th of March, 1843. The prospectus, calling for +funds for the development of the invention, makes interesting +reading at this stage of aeronautical development; it was as +follows: + + PROPOSAL. + +For subscriptions of sums of L100, in furtherance of an +Extraordinary Invention not at present safe to be developed by +securing the necessary Patents, for which three times the sum +advanced, namely, L300, is conditionally guaranteed for each +subscription on February 1, 1844, in case of the anticipations +being realised, with the option of the subscribers being +shareholders for the large amount if so desired, but not +otherwise. + --------- +An Invention has recently been discovered, which if ultimately +successful will be without parallel even in the age which +introduced to the world the wonderful effects of gas and of +steam. + +The discovery is of that peculiar nature, so simple in principle +yet so perfect in all the ingredients required for complete and +permanent success, that to promulgate it at present would wholly +defeat its development by the immense competition which would +ensue, and the views of the originator be entirely frustrated. + +This work, the result of years of labour and study, presents a +wonderful instance of the adaptation of laws long since proved +to the scientific world combined with established principles so +judiciously and carefully arranged, as to produce a discovery +perfect in all its parts and alike in harmony with the laws of +Nature and of science. + +The Invention has been subjected to several tests and +examinations and the results are most satisfactory so much so +that nothing but the completion of the undertaking is required +to determine its practical operation, which being once +established its utility is undoubted, as it would be a necessary +possession of every empire, and it were hardly too much to say, +of every individual of competent means in the civilised world. + +Its qualities and capabilities are so vast that it were +impossible and, even if possible, unsafe to develop them +further, but some idea may be formed from the fact that as a +preliminary measure patents in Great Britain Ireland, Scotland, +the Colonies, France, Belgium, and the United States, and every +other country where protection to the first discoveries of an +Invention is granted, will of necessity be immediately obtained, +and by the time these are perfected, which it is estimated will +be in the month of February, the Invention will be fit for +Public Trial, but until the Patents are sealed any further +disclosure would be most dangerous to the principle on which it +is based. + +Under these circumstances, it is proposed to raise an +immediate sum of L2,000 in furtherance of the Projector's views, +and as some protection to the parties who may embark in the +matter, that this is not a visionary plan for objects +imperfectly considered, Mr Colombine, to whom the secret has +been confided, has allowed his name to be used on the occasion, +and who will if referred to corroborate this statement, and +convince any inquirer of the reasonable prospects of large +pecuniary results following the development of the Invention. + +It is, therefore, intended to raise the sum of L2,000 in twenty +sums of L100 each (of which any subscriber may take one or more +not exceeding five in number to be held by any individual) the +amount of which is to be paid into the hands of Mr Colombine as +General Manager of the concern to be by him appropriated in +procuring the several Patents and providing the expenses +incidental to the works in progress. For each of which sums of +L100 it is intended and agreed that twelve months after the 1st +February next, the several parties subscribing shall receive as +an equivalent for the risk to be run the sum of L300 for each of +the sums of L100 now subscribed, provided when the time arrives +the Patents shall be found to answer the purposes intended. + +As full and complete success is alone looked to, no moderate or +imperfect benefit is to be anticipated, but the work, if it once +passes the necessary ordeal, to which inventions of every kind +must be first subject, will then be regarded by every one as the +most astonishing discovery of modern times; no half success can +follow, and therefore the full nature of the risk is immediately +ascertained. + +The intention is to work and prove the Patent by collective +instead of individual aid as less hazardous at first end more +advantageous in the result for the Inventor, as well as others, +by having the interest of several engaged in aiding one common +object--the development of a Great Plan. The failure is not +feared, yet as perfect success might, by possibility, not ensue, +it is necessary to provide for that result, and the parties +concerned make it a condition that no return of the subscribed +money shall be required, if the Patents shall by any unforeseen +circumstances not be capable of being worked at all; against +which, the first application of the money subscribed, that of +securing the Patents, affords a reasonable security, as no one +without solid grounds would think of such an expenditure. + +It is perfectly needless to state that no risk or responsibility +of any kind can arise beyond the payment of the sum to be +subscribed under any circumstances whatever. + +As soon as the Patents shall be perfected and proved it is +contemplated, so far as may be found practicable, to further the +great object in view a Company shall be formed but respecting +which it is unnecessary to state further details, than that a +preference will be given to all those persons who now subscribe, +and to whom shares shall be appropriated according to the larger +amount (being three times the sum to be paid by each person) +contemplated to be returned as soon as the success of the +Invention shall have been established, at their option, or the +money paid, whereby the Subscriber will have the means of either +withdrawing with a large pecuniary benefit, or by continuing his +interest in the concern lay the foundation for participating in +the immense benefit which must follow the success of the plan. + +It is not pretended to conceal that the project is a +speculation--all parties believe that perfect success, and +thence incalculable advantage of every kind, will follow to +every individual joining in this great undertaking; but the +Gentlemen engaged in it wish that no concealment of the +consequences, perfect success, or possible failure, should in +the slightest degree be inferred. They believe this will prove +the germ of a mighty work, and in that belief call for the +operation of others with no visionary object, but a legitimate +one before them, to attain that point where perfect success will +be secured from their combined exertions. + +All applications to be made to D. E. Colombine, Esquire, 8 +Carlton Chambers, Regent Street. + +The applications did not materialise, as was only to be expected +in view of the vagueness of the proposals. Colombine did some +advertising, and Mr Roebuck expressed himself as unwilling to +proceed further in the venture. Henson experimented with models +to a certain extent, while Stringfellow looked for funds for the +construction of a full-sized monoplane. In November of 1843 he +suggested that he and Henson should construct a large model out +of their own funds. On Henson's suggestion Colombine and +Marriott were bought out as regards the original patent, and +Stringfellow and Henson entered into an agreement and set to +work. + +Their work is briefly described in a little pamphlet by F. J. +Stringfellow, entitled A few Remarks on what has been done with +screw-propelled Aero-plane Machines from 1809 to 1892. The +author writes with regard to the work that his father and Henson +undertook:-- + +'They commenced the construction of a small model operated by a +spring, and laid down the larger model 20 ft. from tip to tip +of planes, 3 1/2 ft. wide, giving 70 ft. of sustaining surface, +about 10 more in the tail. The making of this model required +great consideration; various supports for the wings were tried, +so as to combine lightness with firmness, strength and rigidity. + +'The planes were staid from three sets of fish-shaped masts, and +rigged square and firm by flat steel rigging. The engine and +boiler were put in the car to drive two screw-propellers, right +and left-handed, 3 ft. in diameter, with four blades each, +occupying three-quarters of the area of the circumference, set +at an angle of 60 degrees. A considerable time was spent in +perfecting the motive power. Compressed air was tried and +abandoned. Tappets, cams, and eccentrics were all tried, to work +the slide valve, to obtain the best results. The piston rod of +engine passed through both ends of the cylinder, and with long +connecting rods worked direct on the crank of the propellers. +From memorandum of experiments still preserved the following is +a copy of one: June, 27th, 1845, water 50 ozs., spirit 10 ozs., +lamp lit 8.45, gauge moves 8.46, engine started 8.48 (100 lb. +pressure), engine stopped 8.57, worked 9 minutes, 2,288 +revolutions, average 254 per minute. No priming, 40 ozs. water +consumed, propulsion (thrust of propellers), 5 lbs. 4 1/2 ozs. +at commencement, steady, 4 lbs. 1/2 oz., 57 revolutions to 1 oz. +water, steam cut off one-third from beginning. + +'The diameter of cylinder of engine was 1 1/2 inch, length of +stroke 3 inches. + +'In the meantime an engine was also made for the smaller model, +and a wing action tried, but with poor results. The time was +mostly devoted to the larger model, and in 1847 a tent was +erected on Bala Down, about two miles from Chard, and the model +taken up one night by the workmen. The experiments were not so +favourable as was expected. The machine could not support +itself for any distance, but, when launched off, gradually +descended, although the power and surface should have been +ample; indeed, according to latest calculations, the thrust +should have carried more than three times the weight, for there +was a thrust of 5 lbs. from the propellers, and a surface of +over 70 square feet to sustain under 30 lbs., but necessary +speed was lacking.' + +Stringfellow himself explained the failure as follows:-- + +'There stood our aerial protegee in all her purity--too +delicate, too fragile, too beautiful for this rough world; at +least those were my ideas at the time, but little did I think +how soon it was to be realised. I soon found, before I had time +to introduce the spark, a drooping in the wings, a flagging in +all the parts. In less than ten minutes the machine was +saturated with wet from a deposit of dew, so that anything like +a trial was impossible by night. I did not consider we could get +the silk tight and rigid enough. Indeed, the framework +altogether was too weak. The steam-engine was the best part. +Our want of success was not for want of power or sustaining +surface, but for want of proper adaptation of the means to the +end of the various parts.' + +Henson, who had spent a considerable amount of money in these +experimental constructions, consoled himself for failure by +venturing into matrimony; in 1849 he went to America, leaving +Stringfellow to continue experimenting alone. From 1846 to 1848 +Stringfellow worked on what is really an epoch-making item in +the history of aeronautics--the first engine-driven aeroplane +which actually flew. The machine in question had a 10 foot +span, and was 2 ft. across in the widest part of the wing; the +length of tail was 3 ft. 6 ins., and the span of tail in the +widest part 22 ins., the total sustaining area being about 14 +sq. ft. The motive power consisted of an engine with a cylinder +of three-quarter inch diameter and a two-inch stroke; between +this and the crank shaft was a bevelled gear giving three +revolutions of the propellers to every stroke of the engine; the +propellers, right and left screw, were four-bladed and 16 inches +in diameter. The total weight of the model with engine was 8 +lbs. Its successful flight is ascribed to the fact that +Stringfellow curved the wings, giving them rigid front edges and +flexible trailing edges, as suggested long before both by Da +Vinci and Borelli, but never before put into practice. + +Mr F. J. Stringfellow, in the pamphlet quoted above, gives the +best account of the flight of this model: 'My father had +constructed another small model which was finished early in +1848, and having the loan of a long room in a disused lace +factory, early in June the small model was moved there for +experiments. The room was about 22 yards long and from 10 to 12 +ft. high.... The inclined wire for starting the machine occupied +less than half the length of the room and left space at the end +for the machine to clear the floor. In the first experiment the +tail was set at too high an angle, and the machine rose too +rapidly on leaving the wire. After going a few yards it slid +back as if coming down an inclined plane, at such an angle that +the point of the tail struck the ground and was broken. The +tail was repaired and set at a smaller angle. The steam was +again got up, and the machine started down the wire, and, upon +reaching the point of self-detachment, it gradually rose until +it reached the farther end of the room, striking a hole in the +canvas placed to stop it. In experiments the machine flew well, +when rising as much as one in seven. The late Rev. J. Riste, +Esq., lace manufacturer, Northcote Spicer, Esq., J. Toms, Esq., +and others witnessed experiments. Mr Marriatt, late of the San +Francisco News Letter brought down from London Mr Ellis, the +then lessee of Cremorne Gardens, Mr Partridge, and Lieutenant +Gale, the aeronaut, to witness experiments. Mr Ellis offered to +construct a covered way at Cremorne for experiments. Mr +Stringfellow repaired to Cremorne, but not much better +accommodations than he had at home were provided, owing to +unfulfilled engagement as to room. Mr Stringfellow was +preparing for departure when a party of gentlemen unconnected +with the Gardens begged to see an experiment, and finding them +able to appreciate his endeavours, he got up steam and started +the model down the wire. When it arrived at the spot where it +should leave the wire it appeared to meet with some obstruction, +and threatened to come to the ground, but it soon recovered +itself and darted off in as fair a flight as it was possible to +make at a distance of about 40 yards, where it was stopped by +the canvas. + +'Having now demonstrated the practicability of making a +steam-engine fly, and finding nothing but a pecuniary loss and +little honour, this experimenter rested for a long time, +satisfied with what he had effected. The subject, however, had +to him special charms, and he still contemplated the renewal of +his experiments.' + +It appears that Stringfellow's interest did not revive +sufficiently for the continuance of the experiments until the +founding of the Aeronautical Society of Great Britain in 1866. +Wenham's paper on Aerial Locomotion read at the first meeting of +the Society, which was held at the Society of Arts under the +Presidency of the Duke of Argyll, was the means of bringing +Stringfellow back into the field. It was Wenham's suggestion, +in the first place, that monoplane design should be abandoned +for the superposition of planes; acting on this suggestion +Stringfellow constructed a model triplane, and also designed a +steam engine of slightly over one horse-power, and a one +horse-power copper boiler and fire box which, although capable +of sustaining a pressure of 500 lbs. to the square inch, weighed +only about 40 lbs. + +Both the engine and the triplane model were exhibited at the +first Aeronautical Exhibition held at the Crystal Palace in +1868. The triplane had a supporting surface of 28 sq. ft.; +inclusive of engine, boiler, fuel, and water its total weight +was under 12 lbs. The engine worked two 21 in. propellers at +600 revolutions per minute, and developed 100 lbs. steam +pressure in five minutes, yielding one-third horse-power. Since +no free flight was allowed in the Exhibition, owing to danger +from fire, the triplane was suspended from a wire in the nave of +the building, and it was noted that, when running along the +wire, the model made a perceptible lift. + +A prize of L100 was awarded to the steam engine as the lightest +steam engine in proportion to its power. The engine and model +together may be reckoned as Stringfellow's best achievement. He +used his L100 in preparation for further experiments, but he +was now an old man, and his work was practically done. Both the +triplane and the engine were eventually bought for the +Washington Museum; Stringfellow's earlier models, together with +those constructed by him in conjunction with Henson, remain in +this country in the Victoria and Albert Museum. + +John Stringfellow died on December 13th, 1883. His place in the +history of aeronautics is at least equal to that of Cayley, and +it may be said that he laid the foundation of such work as was +subsequently accomplished by Maxim, Langley, and their fellows. +It was the coming of the internal combustion engine that +rendered flight practicable, and had this prime mover been +available in John Stringfellow's day the Wright brothers' +achievement might have been antedated by half a century. + + + +V. WENHAM, LE BRIS, AND SOME OTHERS + +There are few outstanding events in the development of +aeronautics between Stringfellow's final achievement and the +work of such men as Lilienthal, Pilcher, Montgomery, and their +kind; in spite of this, the later middle decades of the +nineteenth century witnessed a considerable amount of spade work +both in England and in France, the two countries which led in +the way in aeronautical development until Lilienthal gave honour +to Germany, and Langley and Montgomery paved the way for the +Wright Brothers in America. + +Two abortive attempts characterised the sixties of last century +in France. As regards the first of these, it was carried out by +three men, Nadar, Ponton d'Amecourt, and De la Landelle, who +conceived the idea of a full-sized helicopter machine. +D'Amecourt exhibited a steam model, constructed in 1865, at the +Aeronautical Society's Exhibition in 1868. The engine was +aluminium with cylinders of bronze, driving two screws placed +one above the other and rotating in Opposite directions, but the +power was not sufficient to lift the model. De la Landelle's +principal achievement consisted in the publication in 1863 of a +book entitled Aviation which has a certain historical value; he +got out several designs for large machines on the helicopter +principle, but did little more until the three combined in the +attempt to raise funds for the construction of their +full-sized machine. Since the funds were not forthcoming, +Nadar took to ballooning as the means of raising money; +apparently he found this substitute for real flight sufficiently +interesting to divert him from the study of the helicopter +principle, for the experiment went no further. + +The other experimenter of this period, one Count d'Esterno, took +out a patent in 1864 for a soaring machine which allowed for +alteration of the angle of incidence of the wings in the manner +that was subsequently carried out by the Wright Brothers. It +was not until 1883 that any attempt was made to put this patent +to practical use, and, as the inventor died while it was under +construction, it was never completed. D'Esterno was also +responsible for the production of a work entitled Du Vol des +Oiseaux, which is a very remarkable study of the flight of +birds. + +Mention has already been made of the founding of the +Aeronautical Society of Great Britain, which, since 1918 has +been the Royal Aeronautical Society. 1866 witnessed the first +meeting of the Society under the Presidency of the Duke of +Argyll, when in June, at the Society of Arts, Francis Herbert +Wenham read his now classic paper Aerial Locomotion. Certain +quotations from this will show how clearly Wenham had thought +out the problems connected with flight. + +'The first subject for consideration is the proportion of +surface to weight, and their combined effect in descending +perpendicularly through the atmosphere. The datum is here based +upon the consideration of safety, for it may sometimes be +needful for a living being to drop passively, without muscular +effort. One square foot of sustaining surface for every pound +of the total weight will be sufficient for security. + +'According to Smeaton's table of atmospheric resistances, to +produce a force of one pound on a square foot, the wind must +move against the plane (or which is the same thing, the plane +against the wind), at the rate of twenty-two feet per second, or +1,320 feet per minute, equal to fifteen miles per hour. The +resistance of the air will now balance the weight on the +descending surface, and, consequently, it cannot exceed that +speed. Now, twenty-two feet per second is the velocity acquired +at the end of a fall of eight feet--a height from which a +well-knit man or animal may leap down without much risk of +injury. Therefore, if a man with parachute weigh together 143 +lbs., spreading the same number of square feet of surface +contained in a circle fourteen and a half feet in diameter, he +will descend at perhaps an unpleasant velocity, but with safety +to life and limb. + +'It is a remarkable fact how this proportion of wing-surface to +weight extends throughout a great variety of the flying portion +of the animal kingdom, even down to hornets, bees, and other +insects. In some instances, however, as in the gallinaceous +tribe, including pheasants, this area is somewhat exceeded, but +they are known to be very poor fliers. Residing as they do +chiefly on the ground, their wings are only required for short +distances, or for raising them or easing their descent from +their roosting-places in forest trees, the shortness of their +wings preventing them from taking extended flights. The +wing-surface of the common swallow is rather more than in the +ratio of two square feet per pound, but having also great length +of pinion, it is both swift and enduring in its flight. When on +a rapid course this bird is in the habit of furling its wings +into a narrow compass. The greater extent of surface is +probably needful for the continual variations of speed and +instant stoppages for obtaining its insect food. + +'On the other hand, there are some birds, particularly of the +duck tribe, whose wing-surface but little exceeds half a square +foot, or seventy-two inches per pound, yet they may be classed +among the strongest and swiftest of fliers. A weight of one +pound, suspended from an area of this extent, would acquire a +velocity due to a fall of sixteen feet--a height sufficient for +the destruction or injury of most animals. But when the plane +is urged forward horizontally, in a manner analogous to the +wings of a bird during flight, the sustaining power is greatly +influenced by the form and arrangement of the surface. + +'In the case of perpendicular descent, as a parachute, the +sustaining effect will be much the same, whatever the figure of +the outline of the superficies may be, and a circle perhaps +affords the best resistance of any. Take, for example, a circle +of twenty square feet (as possessed by the pelican) loaded with +as many pounds. This, as just stated, will limit the rate of +perpendicular descent to 1,320 feet per minute. But instead of +a circle sixty-one inches in diameter, if the area is bounded by +a parallelogram ten feet long by two feet broad, and whilst at +perfect freedom to descend perpendicularly, let a force be +applied exactly in a horizontal direction, so as to carry it +edgeways, with the long side foremost, at a forward speed of +thirty miles per hour--just double that of its passive descent: +the rate of fall under these conditions will be decreased most +remarkably, probably to less than one-fifteenth part, or +eighty-eight feet per minute, or one mile per hour.' + +And again: 'It has before been shown how utterly inadequate the +mere perpendicular impulse of a plane is found to be in +supporting a weight, when there is no horizontal motion at the +time. There is no material weight of air to be acted upon, and +it yields to the slightest force, however great the velocity of +impulse may be. On the other hand, suppose that a large bird, +in full flight, can make forty miles per hour, or 3,520 feet per +minute, and performs one stroke per second. Now, during every +fractional portion of that stroke, the wing is acting upon and +obtaining an impulse from a fresh and undisturbed body of air; +and if the vibration of the wing is limited to an arc of two +feet, this by no means represents the small force of action that +would be obtained when in a stationary position, for the impulse +is secured upon a stratum of fifty-eight feet in length of air +at each stroke. So that the conditions of weight of air for +obtaining support equally well apply to weight of air and its +reaction in producing forward impulse. + +'So necessary is the acquirement of this horizontal speed, even +in commencing flight, that most heavy birds, when possible, rise +against the wind, and even run at the top of their speed to make +their wings available, as in the example of the eagle, mentioned +at the commencement of this paper. It is stated that the Arabs, +on horseback, can approach near enough to spear these birds, +when on the plain, before they are able to rise; their habit is +to perch on an eminence, where possible. + +'The tail of a bird is not necessary for flight. A pigeon can +fly perfectly with this appendage cut short off; it probably +performs an important function in steering, for it is to be +remarked, that most birds that have either to pursue or evade +pursuit are amply provided with this organ. + +'The foregoing reasoning is based upon facts, which tend to show +that the flight of the largest and heaviest of all birds is +really performed with but a small amount of force, and that man +is endowed with sufficient muscular power to enable him also to +take individual and extended flights, and that success is +probably only involved in a question of suitable mechanical +adaptations. But if the wings are to be modelled in imitation +of natural examples, but very little consideration will serve to +demonstrate its utter impracticability when applied in these +forms.' + +Thus Wenham, one of the best theorists of his age. The Society +with which this paper connects his name has done work, between +that time and the present, of which the importance cannot be +overestimated, and has been of the greatest value in the +development of aeronautics, both in theory and experiment. The +objects of the Society are to give a stronger impulse to the +scientific study of aerial navigation, to promote the +intercourse of those interested in the subject at home and +abroad, and to give advice and instruction to those who study +the principles upon which aeronautical science is based. From +the date of its foundation the Society has given special study +to dynamic flight, putting this before ballooning. Its library, +its bureau of advice and information, and its meetings, all +assist in forwarding the study of aeronautics, and its +twenty-three early Annual Reports are of considerable value, +containing as they do a large amount of useful information on +aeronautical subjects, and forming practically the basis of +aeronautical science. + +Ante to Wenham, Stringfellow and the French experimenters +already noted, by some years, was Le Bris, a French sea captain, +who appears to have required only a thorough scientific training +to have rendered him of equal moment in the history of gliding +flight with Lilienthal himself. Le Bris, it appears, watched +the albatross and deduced, from the manner in which it supported +itself in the air, that plane surfaces could be constructed and +arranged to support a man in like manner. Octave Chanute, +himself a leading exponent of gliding, gives the best +description of Le Bris's experiments in a work, Progress in +Flying Machines, which, although published as recently as I +1894, is already rare. Chanute draws from a still rarer book, +namely, De la Landelle's work published in 1884. Le Bris +himself, quoted by De la Landelle as speaking of his first +visioning of human flight, describes how he killed an albatross, +and then--'I took the wing of the albatross and exposed it to +the breeze; and lo! in spite of me it drew forward into the +wind; notwithstanding my resistance it tended to rise. Thus I +had discovered the secret of the bird! I comprehended the whole +mystery of flight.' + +This apparently took place while at sea; later on Le Bris, +returning to France, designed and constructed an artificial +albatross of sufficient size to bear his own weight. The fact +that he followed the bird outline as closely as he did attests +his lack of scientific training for his task, while at the same +time the success of the experiment was proof of his genius. The +body of his artificial bird, boat-shaped, was 13 1/2 ft. in +length, with a breadth of 4 ft. at the widest part. The +material was cloth stretched over a wooden framework; in front +was a small mast rigged after the manner of a ship's masts to +which were attached poles and cords with which Le Bris intended +to work the wings. Each wing was 23 ft. in length, giving a +total supporting surface of nearly 220 sq. ft.; the weight of +the whole apparatus was only 92 pounds. For steering, both +vertical and horizontal, a hinged tail was provided, and the +leading edge of each wing was made flexible. In construction +throughout, and especially in that of the wings, Le Bris adhered +as closely as possible to the original albatross. + +He designed an ingenious kind of mechanism which he termed +'Rotules,' which by means of two levers gave a rotary motion to +the front edge of the wings, and also permitted of their +adjustment to various angles. The inventor's idea was to stand +upright in the body of the contrivance, working the levers and +cords with his hands, and with his feet on a pedal by means of +which the steering tail was to be worked. He anticipated that, +given a strong wind, he could rise into the air after the manner +of an albatross, without any need for flapping his wings, and +the account of his first experiment forms one of the most +interesting incidents in the history of flight. It is related +in full in Chanute's work, from which the present account is +summarised. + +Le Bris made his first experiment on a main road near +Douarnenez, at Trefeuntec. From his observation of the +albatross Le Bris concluded that it was necessary to get some +initial velocity in order to make the machine rise; consequently +on a Sunday morning, with a breeze of about 12 miles an hour +blowing down the road, he had his albatross placed on a cart and +set off, with a peasant driver, against the wind. At the outset +the machine was fastened to the cart by a rope running through +the rails on which the machine rested, and secured by a slip +knot on Le Bris's own wrist, so that only a jerk on his part was +necessary to loosen the rope and set the machine free. On each +side walked an assistant holding the wings, and when a turn of +the road brought the machine full into the wind these men were +instructed to let go, while the driver increased the pace from a +walk to a trot. Le Bris, by pressure on the levers of the +machine, raised the front edges of his wings slightly; they took +the wind almost instantly to such an extent that the horse, +relieved of a great part of the weight he had been drawing, +turned his trot into a gallop. Le Bris gave the jerk of the +rope that should have unfastened the slip knot, but a concealed +nail on the cart caught the rope, so that it failed to run. The +lift of the machine was such, however, that it relieved the +horse of very nearly the weight of the cart and driver, as well +as that of Le Bris and his machine, and in the end the rails of +the cart gave way. Le Bris rose in the air, the machine +maintaining perfect balance and rising to a height of nearly 300 +ft., the total length of the glide being upwards of an eighth of +a mile. But at the last moment the rope which had originally +fastened the machine to the cart got wound round the driver's +body, so that this unfortunate dangled in the air under Le Bris +and probably assisted in maintaining the balance of the +artificial albatross. Le Bris, congratulating himself on his +success, was prepared to enjoy just as long a time in the air as +the pressure of the wind would permit, but the howls of the +unfortunate driver at the end of the rope beneath him dispelled +his dreams; by working his levers he altered the angle of the +front wing edges so skilfully as to make a very successful +landing indeed for the driver, who, entirely uninjured, +disentangled himself from the rope as soon as he touched the +ground, and ran off to retrieve his horse and cart. + +Apparently his release made a difference in the centre of +gravity, for Le Bris could not manipulate his levers for further +ascent; by skilful manipulation he retarded the descent +sufficiently to escape injury to himself; the machine descended +at an angle, so that one wing, striking the ground in front of +the other, received a certain amount of damage. + +It may have been on account of the reluctance of this same or +another driver that Le Bris chose a different method of +launching himself in making a second experiment with his +albatross. He chose the edge of a quarry which had been +excavated in a depression of the ground; here he assembled his +apparatus at the bottom of the quarry, and by means of a rope +was hoisted to a height of nearly 100 ft. from the quarry +bottom, this rope being attached to a mast which he had erected +upon the edge of the depression in which the quarry was +situated. Thus hoisted, the albatross was swung to face a +strong breeze that blew inland, and Le Bris manipulated his +levers to give the front edges of his wings a downward angle, so +that only the top surfaces should take the wing pressure. Having +got his balance, he obtained a lifting angle of incidence on the +wings by means of his levers, and released the hook that secured +the machine, gliding off over the quarry. On the glide he met +with the inevitable upward current of air that the quarry and +the depression in which it was situated caused; this current +upset the balance of the machine and flung it to the bottom of +the quarry, breaking it to fragments. Le Bris, apparently as +intrepid as ingenious, gripped the mast from which his levers +were worked, and, springing upward as the machine touched earth, +escaped with no more damage than a broken leg. But for the +rebound of the levers he would have escaped even this. + +The interest of these experiments is enhanced by the fact that +Le Bris was a seafaring man who conducted them from love of the +science which had fired his imagination, and in so doing +exhausted his own small means. It was in 1855 that he made +these initial attempts, and twelve years passed before his +persistence was rewarded by a public subscription made at Brest +for the purpose of enabling him to continue his experiments. He +built a second albatross, and on the advice of his friends +ballasted it for flight instead of travelling in it himself. It +was not so successful as the first, probably owing to the lack +of human control while in flight; on one of the trials a height +of 150 ft. was attained, the glider being secured by a thin rope +and held so as to face into the wind. A glide of nearly an +eighth of a mile was made with the rope hanging slack, and, at +the end of this distance, a rise in the ground modified the +force of the wind, whereupon the machine settled down without +damage. A further trial in a gusty wind resulted in the +complete destruction of this second machine; Le Bris had no more +funds, no further subscriptions were likely to materialise, and +so the experiments of this first exponent of the art of gliding +(save for Besnier and his kind) came to an end. They +constituted a notable achievement, and undoubtedly Le Bris +deserves a better place than has been accorded him in the ranks +of the early experimenters. + +Contemporary with him was Charles Spencer, the first man to +practice gliding in England. His apparatus consisted of a pair +of wings with a total area of 30 sq. ft., to which a tail and +body were attached. The weight of this apparatus was some 24 +lbs., and, launching himself on it from a small eminence, as was +done later by Lilienthal in his experiments, the inventor made +flights of over 120 feet. The glider in question was exhibited +at the Aeronautical Exhibition of 1868. + + + +VI. THE AGE OF THE GIANTS + +Until the Wright Brothers definitely solved the problem of +flight and virtually gave the aeroplane its present place in +aeronautics, there were three definite schools of experiment. +The first of these was that which sought to imitate nature by +means of the ornithopter or flapping-wing machines directly +imitative of bird flight; the second school was that which +believed in the helicopter or lifting screw; the third and +eventually successful school is that which followed up the +principle enunciated by Cayley, that of opposing a plane surface +to the resistance of the air by supplying suitable motive power +to drive it at the requisite angle for support. + +Engineering problems generally go to prove that too close an +imitation of nature in her forms of recipro-cating motion is not +advantageous; it is impossible to copy the minutiae of a bird's +wing effectively, and the bird in flight depends on the tiniest +details of its feathers just as much as on the general principle +on which the whole wing is constructed. Bird flight, however, +has attracted many experimenters, including even Lilienthal; +among others may be mentioned F. W. Brearey, who invented what +he called the 'Pectoral cord,' which stored energy on each +upstroke of the artificial wing; E. P. Frost; Major R. Moore, +and especially Hureau de Villeneuve, a most enthusiastic student +of this form of flight, who began his experiments about 1865, +and altogether designed and made nearly 300 artificial birds. +one of his later constructions was a machine in bird form with a +wing span of about 50 ft.; the motive power for this was +supplied by steam from a boiler which, being stationary on the +ground, was connected by a length of hose to the machine. De +Villeneuve, turning on steam for his first trial, obtained +sufficient power to make the wings beat very forcibly; with the +inventor on the machine the latter rose several feet into the +air, whereupon de Villeneuve grew nervous and turned off the +steam supply. The machine fell to the earth, breaking one of +its wings, and it does not appear that de Villeneuve troubled to +reconstruct it. This experiment remains as the greatest success +yet achieved by any machine constructed on the ornithopter +principle. + +It may be that, as forecasted by the prophet Wells, the +flapping-wing machine will yet come to its own and compete with +the aeroplane in efficiency. Against this, however, are the +practical advantages of the rotary mechanism of the aeroplane +propeller as compared with the movement of a bird's wing, which, +according to Marey, moves in a figure of eight. The force +derived from a propeller is of necessity continual, while it is +equally obvious that that derived from a flapping movement is +intermittent, and, in the recovery of a wing after completion of +one stroke for the next, there is necessarily a certain +cessation, if not loss, of power. + +The matter of experiment along any lines in connection with +aviation is primarily one of hard cash. Throughout the whole +history of flight up to the outbreak of the European war +development has been handicapped on the score of finance, and, +since the arrival of the aeroplane, both ornithopter and +helicopter schools have been handicapped by this consideration. +Thus serious study of the efficiency of wings in imitation of +those of the living bird has not been carried to a point that +might win success for this method of propulsion. Even Wilbur +Wright studied this subject and propounded certain theories, +while a later and possibly more scientific student, F. W. +Lanchester, has also contributed empirical conclusions. Another +and earlier student was Lawrence Hargrave, who made a +wing-propelled model which achieved successful flight, and in +1885 was exhibited before the Royal Society of New South Wales. +Hargrave called the principle on which his propeller worked that +of a 'Trochoided plane'; it was, in effect, similar to the +feathering of an oar. + +Hargrave, to diverge for a brief while from the machine to the +man, was one who, although he achieved nothing worthy of special +remark, contributed a great deal of painstaking work to the +science of flight. He made a series of experiments with +man-lifting kites in addition to making a study of flapping-wing +flight. It cannot be said that he set forth any new principle; +his work was mainly imitative, but at the same time by +developing ideas originated in great measure by others he helped +toward the solution of the problem. + +Attempts at flight on the helicopter principle consist in the +work of De la Landelle and others already mentioned. The +possibility of flight by this method is modified by a very +definite disadvantage of which lovers of the helicopter seem to +take little account. It is always claimed for a machine of this +type that it possesses great advantages both in rising and in +landing, since, if it were effective, it would obviously be able +to rise from and alight on any ground capable of containing its +own bulk; a further advantage claimed is that the helicopter +would be able to remain stationary in the air, maintaining +itself in any position by the vertical lift of its propeller. + +These potential assets do not take into consideration the fact +that efficiency is required not only in rising, landing, and +remaining stationary in the air, but also in actual flight. It +must be evident that if a certain amount of the motive force is +used in maintaining the machine off the ground, that amount of +force is missing from the total of horizontal driving power. +Again, it is often assumed by advocates of this form of flight +that the rapidity of climb of the helicopter would be far +greater than that of the driven plane; this view overlooks the +fact that the maintenance of aerodynamic support would claim the +greater part of the engine-power; the rate of ascent would be +governed by the amount of power that could be developed surplus +to that required for maintenance. + +This is best explained by actual figures: assuming that a +propeller 15 ft. in diameter is used, almost 50 horse-power +would be required to get an upward lift of 1,000 pounds; this +amount of horse-power would be continually absorbed in +maintaining the machine in the air at any given level; for +actual lift from one level to another at a speed of eleven feet +per second a further 20 horse-power would be required, which +means that 70 horse-power must be constantly provided for; this +absorption of power in the mere maintenance of aero-dynamic +support is a permanent drawback. + +The attraction of the helicopter lies, probably, in the ease +with which flight is demonstrated by means of models constructed +on this principle, but one truism with regard to the principles +of flight is that the problems change remarkably, and often +unexpectedly, with the size of the machine constructed for +experiment. Berriman, in a brief but very interesting manual +entitled Principles of Flight, assumed that 'there is a +significant dimension of which the effective area is an +expression of the second power, while the weight became an +expression of the third power. Then once again we have the +two-thirds power law militating against the successful +construction of large helicopters, on the ground that the +essential weight increases disproportionately fast to the +effective area. From a consideration of the structural features +of propellers it is evident that this particular relationship +does not apply in practice, but it seems reasonable that some +such governing factor should exist as an explanation of the +apparent failure of all full-sized machines that have been +constructed. Among models there is nothing more strikingly +successful than the toy helicopter, in which the essential +weight is so small compared with the effective area.' + +De la Landelle's work, already mentioned, was carried on a few +years later by another Frenchman, Castel, who constructed a +machine with eight propellers arranged in two fours and driven +by a compressed air motor or engine. The model with which +Castel experimented had a total weight of only 49 lbs.; it rose +in the air and smashed itself by driving against a wall, and the +inventor does not seem to have proceeded further. Contemporary +with Castel was Professor Forlanini, whose design was for a +machine very similar to de la Landelle's, with two superposed +screws. This machine ranks as the second on the helicopter +principle to achieve flight; it remained in the air for no less +than the third of a minute in one of its trials. + +Later experimenters in this direction were Kress, a German; +Professor Wellner, an Austrian; and W. R. Kimball, an American. +Kress, like most Germans, set to the development of an idea +which others had originated; he followed de la Landelle and +Forlanini by fitting two superposed propellers revolving in +opposite directions, and with this machine he achieved good +results as regards horse-power to weight; Kimball, it appears, +did not get beyond the rubber-driven model stage, and any +success he may have achieved was modified by the theory +enunciated by Berriman and quoted above. + +Comparing these two schools of thought, the helicopter and +bird-flight schools, it appears that the latter has the greater +chance of eventual success--that is, if either should ever come +into competition with the aeroplane as effective means of +flight. So far, the aeroplane holds the field, but the whole +science of flight is so new and so full of unexpected +developments that this is no reason for assuming that other +means may not give equal effect, when money and brains are +diverted from the driven plane to a closer imitation of natural +flight. + +Reverting from non-success to success, from consideration of the +two methods mentioned above to the direction in which practical +flight has been achieved, it is to be noted that between the +time of Le Bris, Stringfellow, and their contemporaries, and the +nineties of last century, there was much plodding work carried +out with little visible result, more especially so far as +English students were concerned. Among the incidents of those +years is one of the most pathetic tragedies in the whole history +of aviation, that of Alphonse Penaud, who, in his thirty years +of life, condensed the experience of his predecessors and +combined it with his own genius to state in a published patent +what the aeroplane of to-day should be. Consider the following +abstract of Penaud's design as published in his patent of 1876, +and comparison of this with the aeroplane that now exists will +show very few divergences except for those forced on the +inventor by the fact that the internal combustion engine had not +then developed. The double surfaced planes were to be built +with wooden ribs and arranged with a slight dihedral angle; +there was to be a large aspect ratio and the wings were cambered +as in Stringfellow's later models. Provision was made for +warping the wings while in flight, and the trailing edges were +so designed as to be capable of upward twist while the machine +was in the air. The planes were to be placed above the car, and +provision was even made for a glass wind-screen to give +protection to the pilot during flight. Steering was to be +accomplished by means of lateral and vertical planes forming a +tail; these controlled by a single lever corresponding to the +'joy stick' of the present day plane. + +Penaud conceived this machine as driven by two propellers; +alternatively these could be driven by petrol or steam-fed +motor, and the centre of gravity of the machine while in flight +was in the front fifth of the wings. Penaud estimated from 20 to +30 horse-power sufficient to drive this machine, weighing with +pilot and passenger 2,600 lbs., through the air at a speed of 60 +miles an hour, with the wings set at an angle of incidence of +two degrees. So complete was the design that it even included +instruments, consisting of an aneroid, pressure indicator, an +anemometer, a compass, and a level. There, with few +alterations, is the aeroplane as we know it--and Penaud was +twenty-seven when his patent was published. + +For three years longer he worked, experimenting with models, +contributing essays and other valuable data to French papers on +the subject of aeronautics. His gains were ill health, poverty, +and neglect, and at the age of thirty a pistol shot put an end +to what had promised to be one of the most brilliant careers in +all the history of flight. + +Two years before the publication of Penaud's patent Thomas Moy +experimented at the Crystal Palace with a twin-propelled +aeroplane, steam driven, which seems to have failed mainly +because the internal combustion engine had not yet come to give +sufficient power for weight. Moy anchored his machine to a pole +running on a prepared circular track; his engine weighed 80 lbs. +and, developing only three horse-power, gave him a speed of +12 miles an hour. He himself estimated that the machine would +not rise until he could get a speed of 35 miles an hour, and his +estimate was correct. Two six-bladed propellers were placed +side by side between the two main planes of the machine, which +was supported on a triangular wheeled undercarriage and steered +by fairly conventional tail planes. Moy realised that he could +not get sufficient power to achieve flight, but he went on +experimenting in various directions, and left much data +concerning his experiments which has not yet been deemed worthy +of publication, but which still contains a mass of information +that is of practical utility, embodying as it does a vast amount +of painstaking work. + +Penaud and Moy were followed by Goupil, a Frenchman, who, in +place of attempting to fit a motor to an aeroplane, experimented +by making the wind his motor. He anchored his machine to the +ground, allowing it two feet of lift, and merely waited for a +wind to come along and lift it. The machine was stream lined, +and the wings, curving as in the early German patterns of war +aeroplanes, gave a total lifting surface of about 290 sq. ft. +Anchored to the ground and facing a wind of 19 feet per second, +Goupil's machine lifted its own weight and that of two men as +well to the limit of its anchorage. Although this took place as +late as 1883 the inventor went no further in practical work. He +published a book, however, entitled La Locomotion Aerienne, +which is still of great importance, more especially on the +subject of inherent stability. + +In 1884 came the first patents of Horatio Phillips, whose work +lay mainly in the direction of investigation into the curvature +of plane surfaces, with a view to obtaining the greatest amount +of support. Phillips was one of the first to treat the problem +of curvature of planes as a matter for scientific experiment, +and, great as has been the development of the driven plane in +the 36 years that have passed since he began, there is still +room for investigation into the subject which he studied so +persistently and with such valuable result. + +At this point it may be noted that, with the solitary exception +of Le Bris, practically every student of flight had so far set +about constructing the means of launching humanity into the air +without any attempt at ascertaining the nature and peculiarities +of the sustaining medium. The attitude of experimenters in +general might be compared to that of a man who from boyhood had +grown up away from open water, and, at the first sight of an +expanse of water, set to work to construct a boat with a vague +idea that, since wood would float, only sufficient power was +required to make him an efficient navigator. Accident, perhaps, +in the shape of lack of means of procuring driving power, drove +Le Bris to the form of experiment which he actually carried out; +it remained for the later years of the nineteenth century to +produce men who were content to ascertain the nature of the +support the air would afford before attempting to drive +themselves through it. + +Of the age in which these men lived and worked, giving their all +in many cases to the science they loved, even to life itself, it +may be said with truth that 'there were giants on the earth in +those days,' as far as aeronautics is in question. It was an +age of giants who lived and dared and died, venturing into +uncharted space, knowing nothing of its dangers, giving, as a +man gives to his mistress, without stint and for the joy of the +giving. The science of to-day, compared with the glimmerings +that were in that age of the giants, is a fixed and certain +thing; the problems of to-day are minor problems, for the great +major problem vanished in solution when the Wright Brothers made +their first ascent. In that age of the giants was evolved the +flying man, the new type in human species which found full +expression and came to full development in the days of the war, +achieving feats of daring and endurance which leave the +commonplace landsman staggered at thought of that of which his +fellows prove themselves capable. He is a new type, this flying +man, a being of self-forgetfulness; of such was Lilienthal, of +such was Pilcher; of such in later days were Farman, Bleriot, +Hamel, Rolls, and their fellows; great names that will live for +as long as man flies, adventurers equally with those of the +spacious days of Elizabeth. To each of these came the call, and +he worked and dared and passed, having, perhaps, advanced one +little step in the long march that has led toward the perfecting +of flight. + +It is not yet twenty years since man first flew, but into that +twenty years have been compressed a century or so of progress, +while, in the two decades that preceded it, was compressed still +more. We have only to recall and recount the work of four men: +Lilienthal, Langley, Pilcher, and Clement Ader to see the +immense stride that was made between the time when Penaud pulled +a trigger for the last time and the Wright Brothers first left +the earth. Into those two decades was compressed the +investigation that meant knowledge of the qualities of the air, +together with the development of the one prime mover that +rendered flight a possibility--the internal combustion engine. +The coming and progress of this latter is a thing apart, to be +detailed separately; for the present we are concerned with the +evolution of the driven plane, and with it the evolution of that +daring being, the flying man. The two are inseparable, for the +men gave themselves to their art; the story of Lilienthal's life +and death is the story of his work; the story of Pilcher's work +is that of his life and death. + +Considering the flying man as he appeared in the war period, +there entered into his composition a new element--patriotism-- +which brought about a modification of the type, or, perhaps, made +it appear that certain men belonged to the type who in reality +were commonplace mortals, animated, under normal conditions, by +normal motives, but driven by the stress of the time to take rank +with the last expression of human energy, the flying type. +However that may be, what may be termed the mathematising of +aeronautics has rendered the type itself evanescent; your pilot +of to-day knows his craft, once he is trained, much in the manner +that a driver of a motor-lorry knows his vehicle; design has been +systematised, capabilities have been tabulated; camber, dihedral +angle, aspect ratio, engine power, and plane surface, are +business items of drawing office and machine shop; there is room +for enterprise, for genius, and for skill; once and again there +is room for daring, as in the first Atlantic flight. Yet that +again was a thing of mathematical calculation and petrol storage, +allied to a certain stark courage which may be found even in +landsmen. For the ventures into the unknown, the limit of +daring, the work for work's sake, with the almost certainty that +the final reward was death, we must look back to the age of the +giants, the age when flying was not a business, but romance. + + + +VII. LILIENTHAL AND PILCHER + +There was never a more enthusiastic and consistent student of +the problems of flight than Otto Lilienthal, who was born in +1848 at Anklam, Pomerania, and even from his early school-days +dreamed and planned the conquest of the air. His practical +experiments began when, at the age of thirteen, he and his +brother Gustav made wings consisting of wooden framework covered +with linen, which Otto attached to his arms, and then ran +downhill flapping them. In consequence of possible derision on +the part of other boys, Otto confined these experiments for the +most part to moonlit nights, and gained from them some idea of +the resistance offered by flat surfaces to the air. It was in +1867 that the two brothers began really practical work, +experimenting with wings which, from their design, indicate some +knowledge of Besnier and the history of his gliding experiments; +these wings the brothers fastened to their backs, moving them +with their legs after the fashion of one attempting to swim. +Before they had achieved any real success in gliding the +Franco-German war came as an interruption; both brothers served +in this campaign, resuming their experiments in 1871 at the +conclusion of hostilities. + +The experiments made by the brothers previous to the war had +convinced Otto that previous experimenters in gliding flight had +failed through reliance on empirical conclusions or else through +incomplete observation on their own part, mostly of bird flight. +From 1871 onward Otto Lilenthal (Gustav's interest in the +problem was not maintained as was his brother's) made what is +probably the most detailed and accurate series of observations +that has ever been made with regard to the properties of curved +wing surfaces. So far as could be done, Lilienthal tabulated +the amount of air resistance offered to a bird's wing, +ascertaining that the curve is necessary to flight, as offering +far more resistance than a flat surface. Cayley, and others, +had already stated this, but to Lilienthal belongs the honour of +being first to put the statement to effective proof--he made +over 2,000 gliding flights between 1891 and the regrettable end +of his experiments; his practical conclusions are still regarded +as part of the accepted theory of students of flight. In 1889 +he published a work on the subject of gliding flight which +stands as data for investigators, and, on the conclusions +embodied in this work, he began to build his gliders and +practice what he had preached, turning from experiment with +models to wings that he could use. + +It was in the summer of 1891 that he built his first glider of +rods of peeled willow, over which was stretched strong cotton +fabric; with this, which had a supporting surface of about 100 +square feet, Otto Lilienthal launched himself in the air from a +spring board, making glides which, at first of only a few feet, +gradually lengthened. As his experience of the supporting +qualities of the air progressed he gradually altered his designs +until, when Pilcher visited him in the spring of 1895, he +experimented with a glider, roughly made of peeled willow rods +and cotton fabric, having an area of 150 square feet and +weighing half a hundredweight. By this time Lilienthal had +moved from his springboard to a conical artificial hill which he +had had thrown up on level ground at Grosse Lichterfelde, near +Berlin. This hill was made with earth taken from the +excavations incurred in constructing a canal, and had a cave +inside in which Lilienthal stored his machines. Pilcher, in his +paper on 'Gliding,' [*] gives an excellent short summary of +Lilienthal's experiments, from which the following extracts are +taken:-- + +[*] Aeronautical Classes, No. 5. Royal Aeronautical Society's +publications. + +'At first Lilienthal used to experiment by jumping off a +springboard with a good run. Then he took to practicing on some +hills close to Berlin. In the summer of 1892 he built a +flat-roofed hut on the summit of a hill, from the top of which +he used to jump, trying, of course, to soar as far as possible +before landing.... One of the great dangers with a soaring +machine is losing forward speed, inclining the machine too much +down in front, and coming down head first. Lilienthal was the +first to introduce the system of handling a machine in the air +merely by moving his weight about in the machine; he always +rested only on his elbows or on his elbows and shoulders.... + +'In 1892 a canal was being cut, close to where Lilienthal lived, +in the suburbs of Berlin, and with the surplus earth Lilienthal +had a special hill thrown up to fly from. The country round is +as flat as the sea, and there is not a house or tree near it to +make the wind unsteady, so this was an ideal practicing ground; +for practicing on natural hills is generally rendered very +difficult by shifty and gusty winds.... This hill is 50 feet +high, and conical. Inside the hill there is a cave for the +machines to be kept in.... When Lilienthal made a good flight he +used to land 300 feet from the centre of the hill, having come +down at an angle of 1 in 6; but his best flights have been at an +angle of about 1 in 10. + +'If it is calm, one must run a few steps down the hill, holding +the machine as far back on oneself as possible, when the air +will gradually support one, and one slides off the hill into the +air. If there is any wind, one should face it at starting; to +try to start with a side wind is most unpleasant. It is +possible after a great deal of practice to turn in the air, and +fairly quickly. This is accomplished by throwing one's weight +to one side, and thus lowering the machine on that side towards +which one wants to turn. Birds do the same thing-- crows and +gulls show it very clearly. Last year Lilienthal chiefly +experimented with double-surfaced machines. These were very +much like the old machines with awnings spread above them. + +'The object of making these double-surfaced machines was to get +more surface without increasing the length and width of the +machine. This, of course, it does, but I personally object to +any machine in which the wing surface is high above the weight. +I consider that it makes the machine very difficult to handle in +bad weather, as a puff of wind striking the surface, high above +one, has a great tendency to heel the machine over. + +'Herr Lilienthal kindly allowed me to sail down his hill in one +of these double-surfaced machines last June. With the great +facility afforded by his conical hill the machine was handy +enough; but I am afraid I should not be able to manage one at +all in the squally districts I have had to practice in over +here. + +'Herr Lilienthal came to grief through deserting his old method +of balancing. In order to control his tipping movements more +rapidly he attached a line from his horizontal rudder to his +head, so that when he moved his head forward it would lift the +rudder and tip the machine up in front, and vice versa. He was +practicing this on some natural hills outside Berlin, and he +apparently got muddled with the two motions, and, in trying to +regain speed after he had, through a lull in the wind, come to +rest in the air, let the machine get too far down in front, came +down head first and was killed.' + +Then in another passage Pilcher enunciates what is the true +value of such experiments as Lilienthal--and, subsequently, he +himself--made: 'The object of experimenting with soaring +machines,' he says, 'is to enable one to have practice in +starting and alighting and controlling a machine in the air. +They cannot possibly float horizontally in the air for any +length of time, but to keep going must necessarily lose in +elevation. They are excellent schooling machines, and that is +all they are meant to be, until power, in the shape of an engine +working a screw propeller, or an engine working wings to drive +the machine forward, is added; then a person who is used to +soaring down a hill with a simple soaring machine will be able +to fly with comparative safety. One can best compare them to +bicycles having no cranks, but on which one could learn to +balance by coming down an incline.' + +It was in 1895 that Lilienthal passed from experiment with the +monoplane type of glider to the construction of a biplane glider +which, according to his own account, gave better results than +his previous machines. 'Six or seven metres velocity of wind,' +he says, 'sufficed to enable the sailing surface of 18 square +metres to carry me almost horizontally against the wind from the +top of my hill without any starting jump. If the wind is +stronger I allow myself to be simply lifted from the point of +the hill and to sail slowly towards the wind. The direction of +the flight has, with strong wind, a strong upwards tendency. I +often reach positions in the air which are much higher than my +starting point. At the climax of such a line of flight I +sometimes come to a standstill for some time, so that I am +enabled while floating to speak with the gentlemen who wish to +photograph me, regarding the best position for the +photographing.' + +Lilienthal's work did not end with simple gliding, though he did +not live to achieve machine-driven flight. Having, as he +considered, gained sufficient experience with gliders, he +constructed a power-driven machine which weighed altogether +about 90 lbs., and this was thoroughly tested. The extremities +of its wings were made to flap, and the driving power was +obtained from a cylinder of compressed carbonic acid gas, +released through a hand-operated valve which, Lilienthal +anticipated, would keep the machine in the air for four minutes. +There were certain minor accidents to the mechanism, which +delayed the trial flights, and on the day that Lilienthal had +determined to make his trial he made a long gliding flight with +a view to testing a new form of rudder that--as Pilcher +relates--was worked by movements of his head. His death came +about through the causes that Pilcher states; he fell from a +height of 50 feet, breaking his spine, and the next day he died. + +It may be said that Lilienthal accomplished as much as any one +of the great pioneers of flying. As brilliant in his +conceptions as da Vinci had been in his, and as conscientious a +worker as Borelli, he laid the foundations on which Pilcher, +Chanute, and Professor Montgomery were able to build to such +good purpose. His book on bird flight, published in 1889, with +the authorship credited both to Otto and his brother Gustav, is +regarded as epoch-making; his gliding experiments are no less +entitled to this description. + +In England Lilienthal's work was carried on by Percy Sinclair +Pilcher, who, born in 1866, completed six years' service in the +British Navy by the time that he was nineteen, and then went +through a course of engineering, subsequently joining Maxim in +his experimental work. It was not until 1895 that he began +to build the first of the series of gliders with which he earned +his plane among the pioneers of flight. Probably the best +account of Pilcher's work is that given in the Aeronautical +Classics issued by the Royal Aeronautical Society, from which +the following account of Pilcher's work is mainly abstracted.[*] + +[*] Aeronautical Classes, No. 5. Royal Aeronautical Society +publications. + +The 'Bat,' as Pilcher named his first glider, was a monoplane +which he completed before he paid his visit to Lilienthal in +1895. Concerning this Pilcher stated that he purposely finished +his own machine before going to see Lilienthal, so as to get the +greatest advantage from any original ideas he might have; he was +not able to make any trials with this machine, however, until +after witnessing Lilienthal's experiments and making several +glides in the biplane glider which Lilienthal constructed. + + +The wings of the 'Bat' formed a pronounced dihedral angle; the +tips being raised 4 feet above the body. The spars forming the +entering edges of the wings crossed each other in the centre and +were lashed to opposite sides of the triangle that served as a +mast for the stay-wires that guyed the wings. The four ribs of +each wing, enclosed in pockets in the fabric, radiated fanwise +from the centre, and were each stayed by three steel piano-wires +to the top of the triangular mast, and similarly to its base. +These ribs were bolted down to the triangle at their roots, and +could be easily folded back on to the body when the glider was +not in use. A small fixed vertical surface was carried in the +rear. The framework and ribs were made entirely of Riga pine; +the surface fabric was nainsook. The area of the machine was +150 square feet; its weight 45 lbs.; so that in flight, with +Pilcher's weight of 145 lbs. added, it carried one and a half +pounds to the square foot. + +Pilcher's first glides, which he carried out on a grass hill on +the banks of the Clyde near Cardross, gave little result, owing +to the exaggerated dihedral angle of the wings, and the absence +of a horizontal tail. The 'Bat 'was consequently reconstructed +with a horizontal tail plane added to the vertical one, and with +the wings lowered so that the tips were only six inches above +the level of the body. The machine now gave far better results; +on the first glide into a head wind Pilcher rose to a height of +twelve feet and remained in the the air for a third of a minute; +in the second attempt a rope was used to tow the glider, which +rose to twenty feet and did not come to earth again until nearly +a minute had passed. With experience Pilcher was able to +lengthen his glide and improve his balance, but the dropped wing +tips made landing difficult, and there were many breakages. + +In consequence of this Pilcher built a second glider which he +named the 'Beetle,' because, as he said, it looked like one. In +this the square-cut wings formed almost a continuous plane, +rigidly fixed to the central body, which consisted of a shaped +girder. These wings were built up of five transverse bamboo +spars, with two shaped ribs running from fore to aft of each +wing, and were stayed overhead to a couple of masts. The tail, +consisting of two discs placed crosswise (the horizontal one +alone being movable), was carried high up in the rear. With the +exception of the wing-spars, the whole framework was built of +white pine. The wings in this machine were actually on a higher +level than the operator's head; the centre of gravity was, +consequently, very low, a fact which, according to Pilcher's own +account, made the glider very difficult to handle. Moreover, the +weight of the 'Beetle,' 80 lbs., was considerable; the body had +been very solidly built to enable it to carry the engine which +Pilcher was then contemplating; so that the glider carried some +225 lbs. with its area of 170 square feet--too great a mass for +a single man to handle with comfort. + +It was in the spring of 1896 that Pilcher built his third +glider, the 'Gull,' with 300 square feet of area and a weight of +55 lbs. The size of this machine rendered it unsuitable for +experiment in any but very calm weather, and it incurred such +damage when experiments were made in a breeze that Pilcher found +it necessary to build a fourth, which he named the 'Hawk.' This +machine was very soundly built, being constructed of bamboo, +with the exception of the two main transverse beams. The wings +were attached to two vertical masts, 7 feet high, and 8 feet +apart, joined at their summits and their centres by two wooden +beams. Each wing had nine bamboo ribs, radiating from its mast, +which was situated at a distance of 2 feet 6 inches from the +forward edge of the wing. Each rib was rigidly stayed at the +top of the mast by three tie-wires, and by a similar number to +the bottom of the mast, by which means the curve of each wing +was maintained uniformly. The tail was formed of a triangular +horizontal surface to which was affixed a triangular vertical +surface, and was carried from the body on a high bamboo mast, +which was also stayed from the masts by means of steel wires, +but only on its upper surface, and it was the snapping of one of +these guy wires which caused the collapse of the tail support +and brought about the fatal end of Pilcher's experiments. In +flight, Pilcher's head, shoulders, and the greater part of his +chest projected above the wings. He took up his position by +passing his head and shoulders through the top aperture formed +between the two wings, and resting his forearms on the +longitudinal body members. A very simple form of undercarriage, +which took the weight off the glider on the ground, was fitted, +consisting of two bamboo rods with wheels suspended on steel +springs. + +Balance and steering were effected, apart from the high degree +of inherent stability afforded by the tail, as in the case of +Lilienthal's glider, by altering the position of the body. With +this machine Pilcher made some twelve glides at Eynsford in Kent +in the summer of 1896, and as he progressed he increased the +length of his glides, and also handled the machine more easily, +both in the air and in landing. He was occupied with plans for +fitting an engine and propeller to the 'Hawk,' but, in these +early days of the internal combustion engine, was unable to get +one light enough for his purpose. There were rumours of an +engine weighing 15 lbs. which gave 1 horse-power, and was +reported to be in existence in America, but it could not be +traced. + +In the spring of 1897 Pilcher took up his gliding experiments +again, obtaining what was probably the best of his glides on +June 19th, when he alighted after a perfectly balanced glide of +over 250 yards in length, having crossed a valley at a +considerable height. From his various experiments he concluded +that once the machine was launched in the air an engine of, at +most, 3 horse-power would suffice for the maintenance of +horizontal flight, but he had to allow for the additional weight +of the engine and propeller, and taking into account the +comparative inefficiency of the propeller, he planned for an +engine of 4 horse-power. Engine and propeller together were +estimated at under 44 lbs. weight, the engine was to be fitted +in front of the operator, and by means of an overhead shaft was +to operate the propeller situated in rear of the wings. 1898 +went by while this engine was under construction. Then in 1899 +Pilcher became interested in Lawrence Hargrave's soaring kites, +with which he carried out experiments during the summer of 1899. +It is believed that he intended to incorporate a number of these +kites in a new machine, a triplane, of which the fragments +remaining are hardly sufficient to reconstitute the complete +glider. This new machine was never given a trial. For on +September 30th, 1899, at Stamford Hall, Market Harborough, +Pilcher agreed to give a demonstration of gliding flight, but +owing to the unfavourable weather he decided to postpone the +trial of the new machine and to experiment with the 'Hawk,' +which was intended to rise from a level field, towed by a line +passing over a tackle drawn by two horses. At the first trial +the machine rose easily, but the tow-line snapped when it was +well clear of the ground, and the glider descended, weighed down +through being sodden with rain. Pilcher resolved on a second +trial, in which the glider again rose easily to about thirty +feet, when one of the guy wires of the tail broke, and the tail +collapsed; the machine fell to the ground, turning over, and +Pilcher was unconscious when he was freed from the wreckage. + +Hopes were entertained of his recovery, but he died on Monday, +October 2nd, 1899, aged only thirty-four. His work in the cause +of flying lasted only four years, but in that time his actual +accomplishments were sufficient to place his name beside that of +Lilienthal, with whom he ranks as one of the greatest exponents +of gliding flight. + + + +VIII. AMERICAN GLIDING EXPERIMENTS + +While Pilcher was carrying on Lilienthal's work in England, the +great German had also a follower in America; one Octave Chanute, +who, in one of the statements which he has left on the subject +of his experiments acknowledges forty years' interest in the +problem of flight, did more to develop the glider in America +than--with the possible exception of Montgomery--any other man. +Chanute had all the practicality of an American; he began his +work, so far as actual gliding was concerned, with a full-sized +glider of the Lilienthal type, just before Lilienthal was +killed. In a rather rare monograph, entitled Experiments in +Flying, Chanute states that he found the Lilienthal glider +hazardous and decided to test the value of an idea of his own; +in this he followed the same general method, but reversed the +principle upon which Lilienthal had depended for maintaining his +equilibrium in the air. Lilienthal had shifted the weight of +his body, under immovable wings, as fast and as far as the +sustaining pressure varied under his surfaces; this shifting was +mainly done by moving the feet, as the actions required were +small except when alighting. Chanute's idea was to have the +operator remain seated in the machine in the air, and to +intervene only to steer or to alight; moving mechanism was +provided to adjust the wings automatically in order to restore +balance when necessary. + +Chanute realised that experiments with models were of little +use; in order to be fully instructive, these experiments should +be made with a full-sized machine which carried its operator, +for models seldom fly twice alike in the open air, and no +relation can be gained from them of the divergent air currents +which they have experienced. Chanute's idea was that any flying +machine which might be constructed must be able to operate in a +wind; hence the necessity for an operator to report upon what +occurred in flight, and to acquire practical experience of the +work of the human factor in imitation of bird flight. From this +point of view he conducted his own experiments; it must be noted +that he was over sixty years of age when he began, and, being no +longer sufficiently young and active to perform any but short +and insignificant glides, the courage of the man becomes all the +more noteworthy; he set to work to evolve the state required by +the problem of stability, and without any expectation of +advancing to the construction of a flying machine which might be +of commercial value. His main idea was the testing of devices +to secure equilibrium; for this purpose he employed assistants +to carry out the practical work, where he himself was unable to +supply the necessary physical energy. + +Together with his assistants he found a suitable place for +experiments among the sandhills on the shore of Lake Michigan, +about thirty miles eastward from Chicago. Here a hill about +ninety-five feet high was selected as a point from which +Chanute's gliders could set off; in practice, it was found that +the best observation was to be obtained from short glides at +low speed, and, consequently, a hill which was only sixty-one +feet above the shore of the lake was employed for the +experimental work done by the party. + +In the years 1896 and 1897, with parties of from four to six +persons, five full-sized gliders were tried out, and from these +two distinct types were evolved: of these one was a machine +consisting of five tiers of wings and a steering tail, and the +other was of the biplane type; Chanute believed these to be +safer than any other machine previously evolved, solving, as he +states in his monograph, the problem of inherent equilibrium as +fully as this could be done. Unfortunately, very few +photographs were taken of the work in the first year, but one +view of a multiple wing-glider survives, showing the machine in +flight. In 1897 a series of photographs was taken exhibiting +the consecutive phases of a single flight; this series of +photographs represents the experience gained in a total of about +one thousand glides, but the point of view was varied so as to +exhibit the consecutive phases of one single flight. + +The experience gained is best told in Chanute's own words. 'The +first thing,' he says, 'which we discovered practically was that +the wind flowing up a hill-side is not a steadily-flowing +current like that of a river. It comes as a rolling mass, full +of tumultuous whirls and eddies, like those issuing from a +chimney; and they strike the apparatus with constantly varying +force and direction, sometimes withdrawing support when most +needed. It has long been known, through instrumental +observations, that the wind is constantly changing in force and +direction; but it needed the experience of an operator afloat on +a gliding machine to realise that this all proceeded from +cyclonic action; so that more was learned in this respect in a +week than had previously been acquired by several years of +experiments with models. There was a pair of eagles, living in +the top of a dead tree about two miles from our tent, that came +almost daily to show us how such wind effects are overcome and +utilised. The birds swept in circles overhead on pulseless +wings, and rose high up in the air. Occasionally there was a +side-rocking motion, as of a ship rolling at sea, and then the +birds rocked back to an even keel; but although we thought the +action was clearly automatic, and were willing to learn, our +teachers were too far off to show us just how it was done, and +we had to experiment for ourselves.' + +Chanute provided his multiple glider with a seat, but, since +each glide only occupied between eight and twelve seconds, there +was little possibility of the operator seating himself. With +the multiple glider a pair of horizontal bars provided rest for +the arms, and beyond these was a pair of vertical bars which the +operator grasped with his hands; beyond this, the operator was +in no way attached to the machine. He took, at the most, four +running steps into the wind, which launched him in the air, and +thereupon he sailed into the wind on a generally descending +course. In the matter of descent Chanute observed the sparrow +and decided to imitate it. 'When the latter,' he says, +'approaches the street, he throws his body back, tilts his +outspread wings nearly square to the course, and on the cushion +of air thus encountered he stops his speed and drops lightly to +the ground. So do all birds. We tried it with misgivings, but +found it perfectly effective. The soft sand was a great +advantage, and even when the experts were racing there was not a +single sprained ankle.' + +With the multiple winged glider some two to three hundred glides +were made without any accident either to the man or to the +machine, and the action was found so effective, the principle so +sound, that full plans were published for the benefit of any +experimenters who might wish to improve on this apparatus. The +American Aeronautical Annual for 1897 contains these plans; +Chanute confessed that some movement on the part of the operator +was still required to control the machine, but it was only a +seventh or a sixth part of the movement required for control of +the Lilienthal type. + +Chanute waxed enthusiastic over the possibilities of gliding, +concerning which he remarks that 'There is no more delightful +sensation than that of gliding through the air. All the +faculties are on the alert, and the motion is astonishingly +smooth and elastic. The machine responds instantly to the +slightest movement of the operator; the air rushes by one's +ears; the trees and bushes flit away underneath, and the landing +comes all too quickly. Skating, sliding, and bicycling are not +to be compared for a moment to aerial conveyance, in which, +perhaps, zest is added by the spice of danger. For it must be +distinctly understood that there is constant danger in such +preliminary experiments. When this hazard has been eliminated +by further evolution, gliding will become a most popular sport.' + +Later experiments proved that the biplane type of glider gave +better results than the rather cumbrous model consisting of five +tiers of planes. Longer and more numerous glides, to the number +of seven to eight hundred, were obtained, the rate of descent +being about one in six. The longest distance traversed was +about 120 yards, but Chanute had dreams of starting from a hill +about 200 feet high, which would have given him gliding flights +of 1,200 feet. He remarked that 'In consequence of the speed +gained by running, the initial stage of the flight is nearly +horizontal, and it is thrilling to see the operator pass from +thirty to forty feet overhead, steering his machine, undulating +his course, and struggling with the wind-gusts which whistle +through the guy wires. The automatic mechanism restores the +angle of advance when compromised by variations of the breeze; +but when these come from one side and tilt the apparatus, the +weight has to be shifted to right the machine... these gusts +sometimes raise the machine from ten to twenty feet vertically, +and sometimes they strike the apparatus from above, causing it +to descend suddenly. When sailing near the ground, these +vicissitudes can be counteracted by movements of the body from +three to four inches; but this has to be done instantly, for +neither wings nor gravity will wait on meditation. At a height +of three hundred or four hundred feet the regulating mechanism +would probably take care of these wind-gusts, as it does, in +fact, for their minor variations. The speed of the machine is +generally about seventeen miles an hour over the ground, and +from twenty-two to thirty miles an hour relative to the air. +Constant effort was directed to keep down the velocity, which +was at times fifty-two miles an hour. This is the purpose of +the starting and gliding against the wind, which thus furnishes +an initial velocity without there being undue speed at the +landing. The highest wind we dared to experiment in blew at +thirty-one miles an hour; when the wind was stronger, we waited +and watched the birds.' + +Chanute details an amusing little incident which occurred in the +course of experiment with the biplane glider. He says that 'We +had taken one of the machines to the top of the hill, and loaded +its lower wings with sand to hold it while we e went to lunch. +A gull came strolling inland, and flapped full-winged to +inspect. He swept several circles above the machine, stretched +his neck, gave a squawk and went off. Presently he returned +with eleven other gulls, and they seemed to hold a conclave +about one hundred feet above the big new white bird which they +had discovered on the sand. They circled round after round, and +once in a while there was a series of loud peeps, like those of +a rusty gate, as if in conference, with sudden flutterings, as +if a terrifying suggestion had been made. The bolder birds +occasionally swooped downwards to inspect the monster more +closely; they twisted their heads around to bring first one eye +and then the other to bear, and then they rose again. After +some seven or eight minutes of this performance, they evidently +concluded either that the stranger was too formidable to tackle, +if alive, or that he was not good to eat, if dead, and they flew +off to resume fishing, for the weak point about a bird is his +stomach.' + +The gliders were found so stable, more especially the biplane +form, that in the end Chanute permitted amateurs to make trials +under guidance, and throughout the whole series of experiments +not a single accident occurred. Chanute came to the conclusion +that any young, quick, and handy man could master a gliding +machine almost as soon as he could get the hang of a bicycle, +although the penalty for any mistake would be much more severe. + +At the conclusion of his experiments he decided that neither the +multiple plane nor the biplane type of glider was sufficiently +perfected for the application of motive power. In spite of the +amount of automatic stability that he had obtained he considered +that there was yet more to be done, and he therefore advised +that every possible method of securing stability and safety +should be tested, first with models, and then with full-sized +machines; designers, he said, should make a point of practice in +order to make sure of the action, to proportion and adjust the +parts of their machine, and to eliminate hidden defects. +Experimental flight, he suggested, should be tried over water, +in order to break any accidental fall; when a series of +experiments had proved the stability of a glider, it would then +be time to apply motive power. He admitted that such a process +would be both costly and slow, but, he said, that 'it greatly +diminished the chance of those accidents which bring a whole +line of investigation into contempt.' He saw the flying machine +as what it has, in fact, been; a child of evolution, carried on +step by step by one investigator after another, through the +stages of doubt and perplexity which lie behind the realm of +possibility, beyond which is the present day stage of actual +performance and promise of ultimate success and triumph over the +earlier, more cumbrous, and slower forms of the transport that +we know. + +Chanute's monograph, from which the foregoing notes have been +comprised, was written soon after the conclusion of his series +of experiments. He does not appear to have gone in for further +practical work, but to have studied the subject from a +theoretical view-point and with great attention to the work done +by others. In a paper contributed in 1900 to the American +Independent, he remarks that 'Flying machines promise better +results as to speed, but yet will be of limited commercial +application. They may carry mails and reach other inaccessible +places, but they cannot compete with railroads as carriers of +passengers or freight. They will not fill the heavens with +commerce, abolish custom houses, or revolutionise the world, for +they will be expensive for the loads which they can carry, and +subject to too many weather contingencies. Success is, however, +probable. Each experimenter has added something to previous +knowledge which his successors can avail of. It now seems +likely that two forms of flying machines, a sporting type and an +exploration type, will be gradually evolved within one or two +generations, but the evolution will be costly and slow, and must +be carried on by well-equipped and thoroughly informed +scientific men; for the casual inventor, who relies upon one or +two happy inspirations, will have no chance of success +whatever.' + +Follows Professor John J. Montgomery, who, in the true American +spirit, describes his own experiments so well that nobody can +possibly do it better. His account of his work was given first +of all in the American Journal, Aeronautics, in January, 1909, +and thence transcribed in the English paper of the same name in +May, 1910, and that account is here copied word for word. It +may, however, be noted first that as far back as 1860, when +Montgomery was only a boy, he was attracted to the study of +aeronautical problems, and in 1883 he built his first machine, +which was of the flapping-wing ornithopter type, and which +showed its designer, with only one experiment, that he must +design some other form of machine if he wished to attain to a +successful flight. Chanute details how, in 1884 and 1885 +Montgomery built three gliders, demonstrating the value of +curved surfaces. With the first of these gliders Montgomery +copied the wing of a seagull; with the second he proved that a +flat surface was virtually useless, and with the third he +pivoted his wings as in the Antoinette type of power-propelled +aeroplane, proving to his own satisfaction that success lay in +this direction. His own account of the gliding flights carried +out under his direction is here set forth, being the best +description of his work that can be obtained:-- + +'When I commenced practical demonstration in my work with +aeroplanes I had before me three points; first, equilibrium; +second, complete control; and third, long continued or soaring +flight. In starting I constructed and tested three sets of +models, each in advance of the other in regard to the +continuance of their soaring powers, but all equally perfect as +to equilibrium and control. These models were tested by +dropping them from a cable stretched between two mountain tops, +with various loads, adjustments and positions. And it made no +difference whether the models were dropped upside down or any +other conceivable position, they always found their equilibrium +immediately and glided safely to earth. + +'Then I constructed a large machine patterned after the first +model, and with the assistance of three cowboy friends +personally made a number of flights in the steep mountains near +San Juan (a hundred miles distant). In making these flights I +simply took the aeroplane and made a running jump. These tests +were discontinued after I put my foot into a squirrel hole in +landing and hurt my leg. + +'The following year I commenced the work on a larger scale, by +engaging aeronauts to ride my aeroplane dropped from balloons. +During this work I used five hot-air balloons and one gas +balloon, five or six aeroplanes, three riders--Maloney, Wilkie, +and Defolco--and had sixteen applicants on my list, and had a +training station to prepare any when I needed them. + +'Exhibitions were given in Santa Cruz, San Jose, Santa Clara, +Oaklands, and Sacramento. The flights that were made, instead +of being haphazard affairs, were in the order of safety and +development. In the first flight of an aeronaut the aeroplane +was so arranged that the rider had little liberty of action, +consequently he could make only a limited flight. In some of +the first flights, the aeroplane did little more than settle in +the air. But as the rider gained experience in each successive +flight I changed the adjustments, giving him more liberty of +action, so he could obtain longer flights and more varied +movements in the flights. But in none of the flights did I have +the adjustments so that the riders had full liberty, as I did +not consider that they had the requisite knowledge and +experience necessary for their safety; and hence, none of my +aeroplanes were launched so arranged that the rider could make +adjustments necessary for a full flight. + +'This line of action caused a good deal of trouble with +aeronauts or riders, who had unbounded confidence and wanted to +make long flights after the first few trials; but I found it +necessary, as they seemed slow in comprehending the important +elements and were willing to take risks. To give them the full +knowledge in these matters I was formulating plans for a large +starting station on the Mount Hamilton Range from which I could +launch an aeroplane capable of carrying two, one of my aeronauts +and myself, so I could teach him by demonstration. But the +disasters consequent on the great earthquake completely stopped +all my work on these lines. The flights that were given were +only the first of the series with aeroplanes patterned after the +first model. There were no aeroplanes constructed according to +the two other models, as I had not given the full demonstration +of the workings of the first, though some remarkable and +startling work was done. On one occasion Maloney, in trying to +make a very short turn in rapid flight, pressed very hard on the +stirrup which gives a screw-shape to the wings, and made a side +somersault. The course of the machine was very much like one +turn of a corkscrew. After this movement the machine continued +on its regular course. And afterwards Wilkie, not to be outdone +by Maloney, told his friends he would do the same, and in a +subsequent flight made two side somersaults, one in one +direction and the other in an opposite, then made a deep dive +and a long glide, and, when about three hundred feet in the air, +brought the aeroplane to a sudden stop and settled to the earth. +After these antics, I decreased the extent of the possible +change in the form of wing-surface, so as to allow only straight +sailing or only long curves in turning. + +'During my work I had a few carping critics that I silenced by +this standing offer: If they would deposit a thousand dollars I +would cover it on this proposition. I would fasten a 150 pound +sack of sand in the rider's seat, make the necessary +adjustments, and send up an aeroplane upside down with a +balloon, the aeroplane to be liberated by a time fuse. If the +aeroplane did not immediately right itself, make a flight, and +come safely to the ground, the money was theirs. + +'Now a word in regard to the fatal accident. The circumstances +are these: The ascension was given to entertain a military +company in which were many of Maloney's friends, and he had told +them he would give the most sensational flight they ever heard +of. As the balloon was rising with the aeroplane, a guy rope +dropping switched around the right wing and broke the tower that +braced the two rear wings and which also gave control over the +tail. We shouted Maloney that the machine was broken, but he +probably did not hear us, as he was at the same time saying, +"Hurrah for Montgomery's airship," and as the break was behind +him, he may not have detected it. Now did he know of the +breakage or not, and if he knew of it did he take a risk so as +not to disappoint his friends? At all events, when the machine +started on its flight the rear wings commenced to flap (thus +indicating they were loose), the machine turned on its back, and +settled a little faster than a parachute. When we reached +Maloney he was unconscious and lived only thirty minutes. The +only mark of any kind on him was a scratch from a wire on the +side of his neck. The six attending physicians were puzzled at +the cause of his death. This is remarkable for a vertical +descent of over 2,000 feet.' + +The flights were brought to an end by the San Francisco +earthquake in April, 1906, which, Montgomery states, 'Wrought +such a disaster that I had to turn my attention to other +subjects and let the aeroplane rest for a time.' Montgomery +resumed experiments in 1911 in California, and in October of +that year an accident brought his work to an end. The report in +the American Aeronautics says that 'a little whirlwind caught +the machine and dashed it head on to the ground; Professor +Montgomery landed on his head and right hip. He did not believe +himself seriously hurt, and talked with his year-old bride in +the tent. He complained of pains in his back, and continued to +grow worse until he died.' + + + +IX. NOT PROVEN + +The early history of flying, like that of most sciences, is +replete with tragedies; in addition to these it contains one +mystery concerning Clement Ader, who was well known among +European pioneers in the development of the telephone, and first +turned his attention to the problems of mechanical flight in +1872. At the outset he favoured the ornithopter principle, +constructing a machine in the form of a bird with a wing-spread +of twenty-six feet; this, according to Ader's conception, was to +fly through the efforts of the operator. The result of such an +attempt was past question and naturally the machine never left +the ground. + +A pause of nineteen years ensued, and then in 1886 Ader turned +his mind to the development of the aeroplane, constructing a +machine of bat-like form with a wingspread of about forty-six +feet, a weight of eleven hundred pounds, and a steam-power plant +of between twenty and thirty horse-power driving a four-bladed +tractor screw. On October 9th, 1890, the first trials of this +machine were made, and it was alleged to have flown a distance +of one hundred and sixty-four feet. Whatever truth there may be +in the allegation, the machine was wrecked through deficient +equilibrium at the end of the trial. Ader repeated the +construction, and on October 14th, 1897, tried out his third +machine at the military establishment at Satory in the presence +of the French military authorities, on a circular track +specially prepared for the experiment. Ader and his friends +alleged that a flight of nearly a thousand feet was made; again +the machine was wrecked at the end of the trial, and there +Ader's practical work may be said to have ended, since no more +funds were forthcoming for the subsidy of experiments. + +There is the bald narrative, but it is worthy of some +amplification. If Ader actually did what he claimed, then the +position which the Wright Brothers hold as first to navigate the +air in a power-driven plane is nullified. Although at this time +of writing it is not a quarter of a century since Ader's +experiment in the presence of witnesses competent to judge on +his accomplishment, there is no proof either way, and whether he +was or was not the first man to fly remains a mystery in the +story of the conquest of the air. + +The full story of Ader's work reveals a persistence and +determination to solve the problem that faced him which was +equal to that of Lilienthal. He began by penetrating into the +interior of Algeria after having disguised himself as an Arab, +and there he spent some months in studying flight as practiced +by the vultures of the district. Returning to France in 1886 he +began to construct the 'Eole,' modelling it, not on the vulture, +but in the shape of a bat. Like the Lilienthal and Pilcher +gliders this machine was fitted with wings which could be +folded; the first flight made, as already noted, on October 9th, +1890, took place in the grounds of the chateau d'Amainvilliers, +near Bretz; two fellow-enthusiasts named Espinosa and Vallier +stated that a flight was actually made; no statement in the +history of aeronautics has been subject of so much question, and +the claim remains unproved. + +It was in September of 1891 that Ader, by permission of the +Minister of War, moved the 'Eole' to the military establishment +at Satory for the purpose of further trial. By this time, +whether he had flown or not, his nineteen years of work in +connection with the problems attendant on mechanical flight had +attracted so much attention that henceforth his work was subject +to the approval of the military authorities, for already it was +recognised that an efficient flying machine would confer an +inestimable advantage on the power that possessed it in the +event of war. At Satory the 'Eole' was alleged to have made a +flight of 109 yards, or, according to another account, 164 feet, +as stated above, in the trial in which the machine wrecked +itself through colliding with some carts which had been placed +near the track--the root cause of this accident, however, was +given as deficient equilibrium. + +Whatever the sceptics may say, there is reason for belief in the +accomplishment of actual flight by Ader with his first machine +in the fact that, after the inevitable official delay of some +months, the French War Ministry granted funds for further +experiment. Ader named his second machine, which he began to +build in May, 1892, the 'Avion,' and--an honour which he well +deserve--that name remains in French aeronautics as descriptive +of the power-driven aeroplane up to this day. + +This second machine, however, was not a success, and it was not +until 1897 that the second 'Avion,' which was the third +power-driven aeroplane of Ader's construction, was ready for +trial. This was fitted with two steam motors of twenty +horse-power each, driving two four-bladed propellers; the wings +warped automatically: that is to say, if it were necessary to +raise the trailing edge of one wing on the turn, the trailing +edge of the opposite wing was also lowered by the same movement; +an under-carriage was also fitted, the machine running on three +small wheels, and levers controlled by the feet of the aviator +actuated the movement of the tail planes. + +On October the 12th, 1897, the first trials of this 'Avion' were +made in the presence of General Mensier, who admitted that the +machine made several hops above the ground, but did not consider +the performance as one of actual flight. The result was so +encouraging, in spite of the partial failure, that, two days +later, General Mensier, accompanied by General Grillon, a +certain Lieutenant Binet, and two civilians named respectively +Sarrau and Leaute, attended for the purpose of giving the +machine an official trial, over which the great controversy +regarding Ader's success or otherwise may be said to have +arisen. + +We will take first Ader's own statement as set out in a very +competent account of his work published in Paris in 1910. Here +are Ader's own words: 'After some turns of the propellers, and +after travelling a few metres, we started off at a lively pace; +the pressure-gauge registered about seven atmospheres; almost +immediately the vibrations of the rear wheel ceased; a little +later we only experienced those of the front wheels at +intervals. 'Unhappily, the wind became suddenly strong, and we +had some difficulty in keeping the "Avion" on the white line. +We increased the pressure to between eight and nine atmospheres, +and immediately the speed increased considerably, and the +vibrations of the wheels were no longer sensible; we were at +that moment at the point marked G in the sketch; the "Avion" +then found itself freely supported by its wings; under the +impulse of the wind it continually tended to go outside the +(prepared) area to the right, in spite of the action of the +rudder. On reaching the point V it found itself in a very +critical position; the wind blew strongly and across the +direction of the white line which it ought to follow; the +machine then, although still going forward, drifted quickly out +of the area; we immediately put over the rudder to the left as +far as it would go; at the same time increasing the pressure +still more, in order to try to regain the course. The "Avion" +obeyed, recovered a little, and remained for some seconds headed +towards its intended course, but it could not struggle against +the wind; instead of going back, on the contrary it drifted +farther and farther away. And ill-luck had it that the drift +took the direction towards part of the School of Musketry, which +was guarded by posts and barriers. Frightened at the prospect +of breaking ourselves against these obstacles, surprised at +seeing the earth getting farther away from under the "Avion," +and very much impressed by seeing it rushing sideways at a +sickening speed, instinctively we stopped everything. What +passed through our thoughts at this moment which threatened a +tragic turn would be difficult to set down. All at once came a +great shock, splintering, a heavy concussion: we had landed.' + +Thus speaks the inventor; the cold official mind gives out a +different account, crediting the 'Avion' with merely a few hops, +and to-day, among those who consider the problem at all, there +is a little group which persists in asserting that to Ader +belongs the credit of the first power-driven flight, while a +larger group is equally persistent in stating that, save for a +few ineffectual hops, all three wheels of the machine never left +the ground. It is past question that the 'Avion' was capable of +power-driven flight; whether it achieved it or no remains an +unsettled problem. + +Ader's work is negative proof of the value of such experiments +as Lilienthal, Pilcher, Chanute, and Montgomery conducted; these +four set to work to master the eccentricities of the air before +attempting to use it as a supporting medium for continuous +flight under power; Ader attacked the problem from the other +end; like many other experimenters he regarded the air as a +stable fluid capable of giving such support to his machine as +still water might give to a fish, and he reckoned that he had +only to produce the machine in order to achieve flight. The +wrecked 'Avion' and the refusal of the French War Ministry to +grant any more funds for further experiment are sufficient +evidence of the need for working along the lines taken by the +pioneers of gliding rather than on those which Ader himself +adopted. + +Let it not be thought that in this comment there is any desire +to derogate from the position which Ader should occupy in any +study of the pioneers of aeronautical enterprise. If he failed, +he failed magnificently, and if he succeeded, then the student +of aeronautics does him an injustice and confers on the Brothers +Wright an honour which, in spite of the value of their work, +they do not deserve. There was one earlier than Ader, Alphonse +Penaud, who, in the face of a lesser disappointment than that +which Ader must have felt in gazing on the wreckage of his +machine, committed suicide; Ader himself, rendered unable to do +more, remained content with his achievement, and with the +knowledge that he had played a good part in the long search +which must eventually end in triumph. Whatever the world might +say, he himself was certain that he had achieved flight. This, +for him, was perforce enough. + +Before turning to consideration of the work accomplished by the +Brothers Wright, and their proved conquest of the air, it is +necessary first to sketch as briefly as may be the experimental +work of Sir (then Mr) Hiram Maxim, who, in his book, Artificial +and Natural Flight, has given a fairly complete account of his +various experiments. He began by experimenting with models, +with screw-propelled planes so attached to a horizontal movable +arm that when the screw was set in motion the plane described a +circle round a central point, and, eventually, he built a giant +aeroplane having a total supporting area of 1,500 square feet, +and a wing-span of fifty feet. It has been thought advisable to +give a fairly full description of the power plant used to the +propulsion of this machine in the section devoted to engine +development. The aeroplane, as Maxim describes it, had five +long and narrow planes projecting from each side, and a main or +central plane of pterygoid aspect. A fore and aft rudder was +provided, and had all the auxiliary planes been put in position +for experimental work a total lifting surface of 6,000 square +feet could have been obtained. Maxim, however, did not use more +than 4,000 square feet of lifting surface even in his later +experiments; with this he judged the machine capable of lifting +slightly under 8,000 lbs. weight, made up of 600 lbs. water in +the boiler and tank, a crew of three men, a supply of naphtha +fuel, and the weight of the machine itself. + +Maxim's intention was, before attempting free flight, to get as +much data as possible regarding the conditions under which +flight must be obtained, by what is known in these days as +'taxi-ing'--that is, running the propellers at sufficient speed +to drive the machine along the ground without actually mounting +into the air. He knew that he had an immense lifting surface +and a tremendous amount of power in his engine even when the +total weight of the experimental plant was taken into +consideration, and thus he set about to devise some means of +keeping the machine on the nine foot gauge rail track which had +been constructed for the trials. At the outset he had a set of +very heavy cast-iron wheels made on which to mount the machine, +the total weight of wheels, axles, and connections being about +one and a half tons. These were so constructed that the light +flanged wheels which supported the machine on the steel rails +could be lifted six inches above the track, still leaving the +heavy wheels on the rails for guidance of the machine. 'This +arrangement,' Maxim states, 'was tried on several occasions, the +machine being run fast enough to lift the forward end off the +track. However, I found considerable difficulty in starting and +stopping quickly on account of the great weight, and the amount +of energy necessary to set such heavy wheels spinning at a high +velocity. The last experiment with these wheels was made when a +head wind was blowing at the rate of about ten miles an hour. +It was rather unsteady, and when the machine was running at its +greatest velocity, a sudden gust lifted not only the front end, +but also the heavy front wheels completely off the track, and +the machine falling on soft ground was soon blown over by the +wind.' + +Consequently, a safety track was provided, consisting of squared +pine logs, three inches by nine inches, placed about two feet +above the steel way and having a thirty-foot gauge. Four extra +wheels were fitted to the machine on outriggers and so adjusted +that, if the machine should lift one inch clear of the steel +rails, the wheels at the ends of the outriggers would engage the +under side of the pine trackway. + +The first fully loaded run was made in a dead calm with 150 lbs. +steam pressure to the square inch, and there was no sign of the +wheels leaving the steel track. On a second run, with 230 lbs. +steam pressure the machine seemed to alternate between adherence +to the lower and upper tracks, as many as three of the outrigger +wheels engaging at the same time, and the weight on the steel +rails being reduced practically to nothing. In preparation for +a third run, in which it was intended to use full power, a +dynamometer was attached to the machine and the engines were +started at 200 lbs. pressure, which was gradually increased to +310 lbs per square inch. The incline of the track, added to the +reading of the dynamometer, showed a total screw thrust of 2,164 +lbs. After the dynamometer test had been completed, and +everything had been made ready for trial in motion, careful +observers were stationed on each side of the track, and the +order was given to release the machine. What follows is best +told in Maxim's own words:-- + +'The enormous screw-thrust started the engine so quickly that it +nearly threw the engineers off their feet, and the machine +bounded over the track at a great rate. Upon noticing a slight +diminution in the steam pressure, I turned on more gas, when +almost instantly the steam commenced to blow a steady blast from +the small safety valve, showing that the pressure was at least +320 lbs. in the pipes supplying the engines with steam. Before +starting on this run, the wheels that were to engage the upper +track were painted, and it was the duty of one of my assistants +to observe these wheels during the run, while another assistant +watched the pressure gauges and dynagraphs. The first part of +the track was up a slight incline, but the machine was lifted +clear of the lower rails and all of the top wheels were fully +engaged on the upper track when about 600 feet had been covered. +The speed rapidly increased, and when 900 feet had been covered, +one of the rear axle trees, which were of two-inch steel tubing, +doubled up and set the rear end of the machine completely free. +The pencils ran completely across the cylinders of the +dynagraphs and caught on the underneath end. The rear end of +the machine being set free, raised considerably above the track +and swayed. At about 1,000 feet, the left forward wheel also +got clear of the upper track, and shortly afterwards the right +forward wheel tore up about 100 feet of the upper track. Steam +was at once shut off and the machine sank directly to the earth, +embedding the wheels in the soft turf without leaving any other +marks, showing most conclusively that the machine was completely +suspended in the air before it settled to the earth. In this +accident, one of the pine timbers forming the upper track went +completely through the lower framework of the machine and broke +a number of the tubes, but no damage was done to the machinery +except a slight injury to one of the screws.' + +It is a pity that the multifarious directions in which Maxim +turned his energies did not include further development of the +aeroplane, for it seems fairly certain that he was as near +solution of the problem as Ader himself, and, but for the +holding-down outer track, which was really the cause of his +accident, his machine would certainly have achieved free flight, +though whether it would have risen, flown and alighted, without +accident, is matter for conjecture. + +The difference between experiments with models and with +full-sized machines is emphasised by Maxim's statement to the +effect that with a small apparatus for ascertaining the power +required for artificial flight, an angle of incidence of one in +fourteen was most advantageous, while with a large machine he +found it best to increase his angle to one in eight in order to +get the maximum lifting effect on a short run at a moderate +speed. He computed the total lifting effect in the experiments +which led to the accident as not less than 10,000 lbs., in which +is proof that only his rail system prevented free flight. + + + +X. SAMUEL PIERPOINT LANGLEY + +Langley was an old man when he began the study of aeronautics, +or, as he himself might have expressed it, the study of +aerodromics, since he persisted in calling the series of +machines he built 'Aerodromes,' a word now used only to denote +areas devoted to use as landing spaces for flying machines; the +Wright Brothers, on the other hand, had the great gift of youth +to aid them in their work. Even so it was a great race between +Langley, aided by Charles Manly, and Wilbur and Orville Wright, +and only the persistent ill-luck which dogged Langley from the +start to the finish of his experiments gave victory to his +rivals. It has been proved conclusively in these later years of +accomplished flight that the machine which Langley launched on +the Potomac River in October of 1903 was fully capable of +sustained flight, and only the accidents incurred in launching +prevented its pilot from being the first man to navigate the air +successfully in a power-driven machine. + +The best account of Langley's work is that diffused throughout a +weighty tome issued by the Smithsonian Institution, entitled the +Langley Memoir on Mechanical Flight, of which about one-third +was written by Langley himself, the remainder being compiled by +Charles M. Manly, the engineer responsible for the construction +of the first radial aero-engine, and chief assistant to Langley +in his experiments. To give a twentieth of the contents of this +volume in the present short account of the development of +mechanical flight would far exceed the amount of space that can +be devoted even to so eminent a man in aeronautics as S. P. +Langley, who, apart from his achievement in the construction of +a power-driven aeroplane really capable of flight, was a +scientist of no mean order, and who brought to the study of +aeronautics the skill of the trained investigator allied to the +inventive resource of the genius. + +That genius exemplified the antique saw regarding the infinite +capacity for taking pains, for the Langley Memoir shows that as +early as 1891 Langley had completed a set of experiments, +lasting through years, which proved it possible to construct +machines giving such a velocity to inclined surfaces that bodies +indefinitely heavier than air could be sustained upon it and +propelled through it at high speed. For full account (very +full) of these experiments, and of a later series leading up to +the construction of a series of 'model aerodromes' capable of +flight under power, it is necessary to turn to the bulky memoir +of Smithsonian origin. + +The account of these experiments as given by Langley himself +reveals the humility of the true investigator. Concerning them, +Langley remarks that, 'Everything here has been done with a view +to putting a trial aerodrome successfully in flight within a few +years, and thus giving an early demonstration of the only kind +which is conclusive in the eyes of the scientific man, as well +as of the general public--a demonstration that mechanical flight +is possible--by actually flying. All that has been done has +been with an eye principally to this immediate result, and all +the experiments given in this book are to be considered only as +approximations to exact truth. All were made with a view, not +to some remote future, but to an arrival within the compass of a +few years at some result in actual flight that could not be +gainsaid or mistaken.' + +With a series of over thirty rubber-driven models Langley +demonstrated the practicability of opposing curved surfaces to +the resistance of the air in such a way as to achieve flight, in +the early nineties of last century; he then set about finding +the motive power which should permit of the construction of +larger machines, up to man-carrying size. The internal +combustion engine was then an unknown quantity, and he had to +turn to steam, finally, as the propulsive energy for his power +plant. The chief problem which faced him was that of the +relative weight and power of his engine; he harked back to the +Stringfellow engine of 1868, which in 1889 came into the +possession of the Smithsonian Institution as a historical +curiosity. Rightly or wrongly Langley concluded on examination +that this engine never had developed and never could develop +more than a tenth of the power attributed to it; consequently he +abandoned the idea of copying the Stringfellow design and set +about making his own engine. + +How he overcame the various difficulties that faced him and +constructed a steam-engine capable of the task allotted to it +forms a story in itself, too long for recital here. His first +power-driven aerodrome of model size was begun in November of +1891, the scale of construction being decided with the idea that +it should be large enough to carry an automatic steering +apparatus which would render the machine capable of maintaining +a long and steady flight. The actual weight of the first model +far exceeded the theoretical estimate, and Langley found that a +constant increase of weight under the exigencies of construction +was a feature which could never be altogether eliminated. The +machine was made principally of steel, the sustaining surfaces +being composed of silk stretched from a steel tube with wooden +attachments. The first engines were the oscillating type, but +were found deficient in power. This led to the construction of +single-acting inverted oscillating engines with high and low +pressure cylinders, and with admission and exhaust ports to +avoid the complication and weight of eccentric and valves. +Boiler and furnace had to be specially designed; an analysis of +sustaining surfaces and the settlement of equilibrium while in +flight had to be overcome, and then it was possible to set about +the construction of the series of model aerodromes and make test +of their 'lift.' + +By the time Langley had advanced sufficiently far to consider it +possible to conduct experiments in the open air, even with these +models, he had got to his fifth aerodrome, and to the year 1894. +Certain tests resulted in failure, which in turn resulted in +further modifications of design, mainly of the engines. By +February of 1895 Langley reported that under favourable +conditions a lift of nearly sixty per cent of the flying weight +was secured, but although this was much more than was required +for flight, it was decided to postpone trials until two machines +were ready for the test. May, 1896, came before actual trials +were made, when one machine proved successful and another, a +later design, failed. The difficulty with these models was that +of securing a correct angle for launching; Langley records how, +on launching one machine, it rose so rapidly that it attained an +angle of sixty degrees and then did a tail slide into the water +with its engines working at full speed, after advancing nearly +forty feet and remaining in the air for about three seconds. +Here, Langley found that he had to obtain greater rigidity in +his wings, owing to the distortion of the form of wing under +pressure, and how he overcame this difficulty constitutes yet +another story too long for the telling here. + +Field trials were first attempted in 1893, and Langley blamed +his launching apparatus for their total failure. There was a +brief, but at the same time practical, success in model flight +in 1894, extending to between six and seven seconds, but this +only proved the need for strengthening of the wing. In 1895 +there was practically no advance toward the solution of the +problem, but the flights of May 6th and November 28th, 1896, +were notably successful. A diagram given in Langley's memoir +shows the track covered by the aerodrome on these two flights; +in the first of them the machine made three complete circles, +covering a distance of 3,200 feet; in the second, that of +November 28th, the distance covered was 4,200 feet, or about +three-quarters of a mile, at a speed of about thirty miles an +hour. + +These achievements meant a good deal; they proved mechanically +propelled flight possible. The difference between them and such +experiments as were conducted by Clement Ader, Maxim, and +others, lay principally in the fact that these latter either did +or did not succeed in rising into the air once, and then, either +willingly or by compulsion, gave up the quest, while Langley +repeated his experiments and thus attained to actual proof of +the possibilities of flight. Like these others, however, he +decided in 1896 that he would not undertake the construction of +a large man-carrying machine. In addition to a multitude of +actual duties, which left him practically no time available for +original research, he had as an adverse factor fully ten years +of disheartening difficulties in connection with his model +machines. It was President McKinley who, by requesting Langley +to undertake the construction and test of a machine which might +finally lead to the development of a flying machine capable of +being used in warfare, egged him on to his final experiment. +Langley's acceptance of the offer to construct such a machine is +contained in a letter addressed from the Smithsonian Institution +on December 12th, 1898, to the Board of Ordnance and +Fortification of the United States War Department; this letter +is of such interest as to render it worthy of reproduction:-- + +'Gentlemen,--In response to your invitation I repeat what I had +the honour to say to the Board--that I am willing, with the +consent of the Regents of this Institution, to undertake for the +Government the further investigation of the subject of the +construction of a flying machine on a scale capable of carrying +a man, the investigation to include the construction, +development and test of such a machine under conditions left as +far as practicable in my discretion, it being understood that my +services are given to the Government in such time as may not be +occupied by the business of the Institution, and without charge. + +'I have reason to believe that the cost of the construction will +come within the sum of $50,000.00, and that not more than +one-half of that will be called for in the coming year. + +'I entirely agree with what I understand to be the wish of the +Board that privacy be observed with regard to the work, and only +when it reaches a successful completion shall I wish to make +public the fact of its success. + +'I attach to this a memorandum of my understanding of some +points of detail in order to be sure that it is also the +understanding of the Board, and I am, gentlemen, with much +respect, your obedient servant, S. P. Langley.' + +One of the chief problems in connection with the construction of +a full-sized apparatus was that of the construction of an +engine, for it was realised from the first that a steam power +plant for a full-sized machine could only be constructed in such +a way as to make it a constant menace to the machine which it +was to propel. By this time (1898) the internal combustion +engine had so far advanced as to convince Langley that it formed +the best power plant available. A contract was made for the +delivery of a twelve horse-power engine to weigh not more than a +hundred pounds, but this contract was never completed, and it +fell to Charles M. Manly to design the five-cylinder radial +engine, of which a brief account is included in the section of +this work devoted to aero engines, as the power plant for the +Langley machine. + +The history of the years 1899 to 1903 in the Langley series of +experiments contains a multitude of detail far beyond the scope +of this present study, and of interest mainly to the designer. +There were frames, engines, and propellers, to be considered, +worked out, and constructed. We are concerned here mainly with +the completed machine and its trials. Of these latter it must +be remarked that the only two actual field trials which took +place resulted in accidents due to the failure of the launching +apparatus, and not due to any inherent defect in the machine. +It was intended that these two trials should be the first of a +series, but the unfortunate accidents, and the fact that no +further funds were forthcoming for continuance of experiments, +prevented Langley's success, which, had he been free to go +through as he intended with his work, would have been certain. + +The best brief description of the Langley aerodrome in its final +form, and of the two attempted trials, is contained in the +official report of Major M. M. Macomb of the United States +Artillery Corps, which report is here given in full:-- + + REPORT + +Experiments with working models which were concluded August 8 +last having proved the principles and calculations on which the +design of the Langley aerodrome was based to be correct, the +next step was to apply these principles to the construction of a +machine of sufficient size and power to permit the carrying of a +man, who could control the motive power and guide its flight, +thus pointing the way to attaining the final goal of producing a +machine capable of such extensive and precise aerial flight, +under normal atmospheric conditions, as to prove of military or +commercial utility. + +Mr C. M. Manly, working under Professor Langley, had, by the +summer of 1903, succeeded in completing an engine-driven machine +which under favourable atmospheric conditions was expected to +carry a man for any time up to half an hour, and to be capable +of having its flight directed and controlled by him. + +The supporting surface of the wings was ample, and experiment +showed the engine capable of supplying more than the necessary +motive power. + +Owing to the necessity of lightness, the weight of the various +elements had to be kept at a minimum, and the factor of safety +in construction was therefore exceedingly small, so that the +machine as a whole was delicate and frail and incapable of +sustaining any unusual strain. This defect was to be corrected +in later models by utilising data gathered in future experiments +under varied conditions. + +One of the most remarkable results attained was the production +of a gasoline engine furnishing over fifty continuous +horse-power for a weight of 120 lbs. + +The aerodrome, as completed and prepared for test, is briefly +described by Professor Langley as 'built of steel, weighing +complete about 730 lbs., supported by 1,040 feet of sustaining +surface, having two propellers driven by a gas engine developing +continuously over fifty brake horse-power.' + +The appearance of the machine prepared for flight was +exceedingly light and graceful, giving an impression to all +observers of being capable of successful flight. + +On October 7 last everything was in readiness, and I witnessed +the attempted trial on that day at Widewater, Va. On the +Potomac. The engine worked well and the machine was launched at +about 12.15 p.m. The trial was unsuccessful because the front +guy-post caught in its support on the launching car and was not +released in time to give free flight, as was intended, but, on +the contrary, caused the front of the machine to be dragged +downward, bending the guy-post and making the machine plunge +into the water about fifty yards in front of the house-boat. +The machine was subsequently recovered and brought back to the +house-boat. The engine was uninjured and the frame only slightly +damaged, but the four wings and rudder were practically destroyed +by the first plunge and subsequent towing back to the house-boat. + +This accident necessitated the removal of the house-boat to +Washington for the more convenient repair of damages. + +On December 8 last, between 4 and 5 p.m., another attempt at a +trial was made, this time at the junction of the Anacostia with +the Potomac, just below Washington Barracks. + +On this occasion General Randolph and myself represented the +Board of Ordnance and Fortification. The launching car was +released at 4.45 p.m. being pointed up the Anacostia towards the +Navy Yard. My position was on the tug Bartholdi, about 150 feet +from and at right angles to the direction of proposed flight. +The car was set in motion and the propellers revolved rapidly, +the engine working perfectly, but there was something wrong with +the launching. The rear guy-post seemed to drag, bringing the +rudder down on the launching ways, and a crashing, rending +sound, followed by the collapse of the rear wings, showed that +the machine had been wrecked in the launching, just how, it was +impossible for me to see. The fact remains that the rear wings +and rudder were wrecked before the machine was free of the ways. +Their collapse deprived the machine of its support in the rear, +and it consequently reared up in front under the action of the +motor, assumed a vertical position, and then toppled over to the +rear, falling into the water a few feet in front of the boat. + +Mr Manly was pulled out of the wreck uninjured and the wrecked +machine--was subsequently placed upon the house-boat, and the +whole brought back to Washington. + +From what has been said it will be seen that these unfortunate +accidents have prevented any test of the apparatus in free +flight, and the claim that an engine-driven, man-carrying +aerodrome has been constructed lacks the proof which actual +flight alone can give. + +Having reached the present stage of advancement in its +development, it would seem highly desirable, before laying down +the investigation, to obtain conclusive proof of the possibility +of free flight, not only because there are excellent reasons to +hope for success, but because it marks the end of a definite +step toward the attainment of the final goal. + +Just what further procedure is necessary to secure successful +flight with the large aerodrome has not yet been decided upon. +Professor Langley is understood to have this subject under +advisement, and will doubtless inform the Board of his final +conclusions as soon as practicable. + +In the meantime, to avoid any possible misunderstanding, it +should be stated that even after a successful test of the +present great aerodrome, designed to carry a man, we are still +far from the ultimate goal, and it would seem as if years of +constant work and study by experts, together with the +expenditure of thousands of dollars, would still be necessary +before we can hope to produce an apparatus of practical utility +on these lines.--Washington, January 6, 1904. + +A subsequent report of the Board of ordnance and Fortification +to the Secretary of War embodied the principal points in Major +Macomb's report, but as early as March 3rd, 1904, the Board came +to a similar conclusion to that of the French Ministry of War in +respect of Clement Ader's work, stating that it was not +'prepared to make an additional allotment at this time for +continuing the work.' This decision was in no small measure due +to hostile newspaper criticisms. Langley, in a letter to the +press explaining his attitude, stated that he did not wish to +make public the results of his work till these were certain, in +consequence of which he refused admittance to newspaper +representatives, and this attitude produced a hostility which +had effect on the United States Congress. An offer was made to +commercialise the invention, but Langley steadfastly refused it. +Concerning this, Manly remarks that Langley had 'given his time +and his best labours to the world without hope of remuneration, +and he could not bring himself, at his stage of life, to consent +to capitalise his scientific work.' + +The final trial of the Langley aerodrome was made on December +8th, 1903; nine days later, on December 17th, the Wright +Brothers made their first flight in a power-propelled machine, +and the conquest of the air was thus achieved. But for the two +accidents that spoilt his trials, the honour which fell to the +Wright Brothers would, beyond doubt, have been secured by Samuel +Pierpoint Langley. + + + +XI. THE WRIGHT BROTHERS + +Such information as is given here concerning the Wright Brothers +is derived from the two best sources available, namely, the +writings of Wilbur Wright himself, and a lecture given by Dr +Griffith Brewer to members of the Royal Aeronautical Society. +There is no doubt that so far as actual work in connection with +aviation accomplished by the two brothers is concerned, Wilbur +Wright's own statements are the clearest and best available. +Apparently Wilbur was, from the beginning, the historian of the +pair, though he himself would have been the last to attempt to +detract in any way from the fame that his brother's work also +deserves. Throughout all their experiments the two were +inseparable, and their work is one indivisible whole; in fact, +in every department of that work, it is impossible to say where +Orville leaves off and where Wilbur begins. + +It is a great story, this of the Wright Brothers, and one worth +all the detail that can be spared it. It begins on the 16th +April, 1867, when Wilbur Wright was born within eight miles of +Newcastle, Indiana. Before Orville's birth on the 19th August, +1871, the Wright family had moved to Dayton, Ohio, and settled +on what is known as the 'West Side' of the town. Here the +brothers grew up, and, when Orville was still a boy in his +teens, he started a printing business, which, as Griffith +Brewer remarks, was only limited by the smallness of his machine +and small quantity of type at his disposal. This machine was in +such a state that pieces of string and wood were incorporated in +it by way of repair, but on it Orville managed to print a boys' +paper which gained considerable popularity in Dayton 'West +Side.' Later, at the age of seventeen, he obtained a more +efficient outfit, with which he launched a weekly newspaper, +four pages in size, entitled The West Side News. After three +months' running the paper was increased in size and Wilbur came +into the enterprise as editor, Orville remaining publisher. In +1894 the two brothers began the publication of a weekly +magazine, Snap-Shots, to which Wilbur contributed a series of +articles on local affairs that gave evidence of the incisive and +often sarcastic manner in which he was able to express himself +throughout his life. Dr Griffith Brewer describes him as a +fearless critic, who wrote on matters of local interest in a +kindly but vigorous manner, which did much to maintain the +healthy public municipal life of Dayton. + +Editorial and publishing enterprise was succeeded by the +formation, just across the road from the printing works, of the +Wright Cycle Company, where the two brothers launched out as +cycle manufacturers with the 'Van Cleve' bicycle, a machine of +great local repute for excellence of construction, and one which +won for itself a reputation that lasted long after it had ceased +to be manufactured. The name of the machine was that of an +ancestor of the brothers, Catherine Van Cleve, who was one of +the first settlers at Dayton, landing there from the River Miami +on April 1st, 1796, when the country was virgin forest. + +It was not until 1896 that the mechanical genius which +characterised the two brothers was turned to the consideration +of aeronautics. In that year they took up the problem +thoroughly, studying all the aeronautical information then in +print. Lilienthal's writings formed one basis for their +studies, and the work of Langley assisted in establishing in +them a confidence in the possibility of a solution to the +problems of mechanical flight. In 1909, at the banquet given by +the Royal Aero Club to the Wright Brothers on their return to +America, after the series of demonstration flights carried out +by Wilbur Wright on the Continent, Wilbur paid tribute to the +great pioneer work of Stringfellow, whose studies and +achievements influenced his own and Orville's early work. He +pointed out how Stringfellow devised an aeroplane having two +propellers and vertical and horizontal steering, and gave due +place to this early pioneer of mechanical flight. + +Neither of the brothers was content with mere study of the work +of others. They collected all the theory available in the books +published up to that time, and then built man-carrying gliders +with which to test the data of Lilienthal and such other +authorities as they had consulted. For two years they conducted +outdoor experiments in order to test the truth or otherwise of +what were enunciated as the principles of flight; after this +they turned to laboratory experiments, constructing a wind +tunnel in which they made thousands of tests with models of +various forms of curved planes. From their experiments they +tabulated thousands of readings, which Griffith Brewer remarks +as giving results equally efficient with those of the elaborate +tables prepared by learned institutions. + +Wilbur Wright has set down the beginnings of the practical +experiments made by the two brothers very clearly. 'The +difficulties,' he says, 'which obstruct the pathway to success +in flying machine construction are of three general classes: +(1) Those which relate to the construction of the sustaining +wings; (2) those which relate to the generation and application +of the power required to drive the machine through the air; (3) +those relating to the balancing and steering of the machine +after it is actually in flight. Of these difficulties two are +already to a certain extent solved. Men already know how to +construct wings, or aeroplanes, which, when driven through the +air at sufficient speed, will not only sustain the weight of the +wings themselves, but also that of the engine and the engineer +as well. Men also know how to build engines and' screws of +sufficient lightness and power to drive these planes at +sustaining speed. Inability to balance and steer still +confronts students of the flying problem, although nearly ten +years have passed (since Lilienthal's success). When this one +feature has been worked out, the age of flying machines will +have arrived, for all other difficulties are of minor +importance. + +'The person who merely watches the flight of a bird gathers the +impression that the bird has nothing to think of but the +flapping of its wings. As a matter of fact, this is a very +small part of its mental labour. Even to mention all the things +the bird must constantly keep in mind in order to fly securely +through the air would take a considerable time. If I take a +piece of paper and, after placing it parallel with the ground, +quickly let it fall, it will not settle steadily down as a +staid, sensible piece of paper ought to do, but it insists on +contravening every recognised rule of decorum, turning over and +darting hither and thither in the most erratic manner, much +after the style of an untrained horse. Yet this is the style of +steed that men must learn to manage before flying can become an +everyday sport. The bird has learned this art of equilibrium, +and learned it so thoroughly that its skill is not apparent to +our sight. We only learn to appreciate it when we can imitate +it. + +'Now, there are only two ways of learning to ride a fractious +horse: one is to get on him and learn by actual practice how +each motion and trick may be best met; the other is to sit on a +fence and watch the beast awhile, and then retire to the house +and at leisure figure out the best way of overcoming his jumps +and kicks. The latter system is the safer, but the former, on +the whole, turns out the larger proportion of good riders. It +is very much the same in learning to ride a flying machine; if +you are looking for perfect safety you will do well to sit on a +fence and watch the birds, but if you really wish to learn you +must mount a machine and become acquainted with its tricks by +actual trial. The balancing of a gliding or flying machine is +very simple in theory. It merely consists in causing the centre +of pressure to coincide with the centre of gravity.' + +These comments are taken from a lecture delivered by Wilbur +Wright before the Western Society of Engineers in September of +1901, under the presidency of Octave Chanute. In that lecture +Wilbur detailed the way in which he and his brother came to +interest themselves in aeronautical problems and constructed +their first glider. He speaks of his own notice of the death of +Lilienthal in 1896, and of the way in which this fatality roused +him to an active interest in aeronautical problems, which was +stimulated by reading Professor Marey's Animal Mechanism, not +for the first time. 'From this I was led to read more modern +works, and as my brother soon became equally interested with +myself, we soon passed from the reading to the thinking, and +finally to the working stage. It seemed to us that the main +reason why the problem had remained so long unsolved was that no +one had been able to obtain any adequate practice. We figured +that Lilienthal in five years of time had spent only about five +hours in actual gliding through the air. The wonder was not +that he had done so little, but that he had accomplished so +much. It would not be considered at all safe for a bicycle +rider to attempt to ride through a crowded city street after +only five hours' practice, spread out in bits of ten seconds +each over a period of five years; yet Lilienthal with this brief +practice was remarkably successful in meeting the fluctuations +and eddies of wind-gusts. We thought that if some method could +be found by which it would be possible to practice by the hour +instead of by the second there would be hope of advancing the +solution of a very difficult problem. It seemed feasible to do +this by building a machine which would be sustained at a speed +of eighteen miles per hour, and then finding a locality where +winds of this velocity were common. With these conditions a +rope attached to the machine to keep it from floating backward +would answer very nearly the same purpose as a propeller driven +by a motor, and it would be possible to practice by the hour, +and without any serious danger, as it would not be necessary to +rise far from the ground, and the machine would not have any +forward motion at all. We found, according to the accepted +tables of air pressure on curved surfaces, that a machine +spreading 200 square feet of wing surface would be sufficient +for our purpose, and that places would easily be found along the +Atlantic coast where winds of sixteen to twenty-five miles were +not at all uncommon. When the winds were low it was our plan to +glide from the tops of sandhills, and when they were +sufficiently strong to use a rope for our motor and fly over one +spot. Our next work was to draw up the plans for a suitable +machine. After much study we finally concluded that tails were +a source of trouble rather than of assistance, and therefore we +decided to dispense with them altogether. It seemed reasonable +that if the body of the operator could be placed in a horizontal +position instead of the upright, as in the machines of +Lilienthal, Pilcher, and Chanute, the wind resistance could be +very materially reduced, since only one square foot instead of +five would be exposed. As a full half horse-power would be +saved by this change, we arranged to try at least the horizontal +position. Then the method of control used by Lilienthal, which +consisted in shifting the body, did not seem quite as quick or +effective as the case required; so, after long study, we +contrived a system consisting of two large surfaces on the +Chanute double-deck plan, and a smaller surface placed a short +distance in front of the main surfaces in such a position that +the action of the wind upon it would counterbalance the effect +of the travel of the centre of pressure on the main surfaces. +Thus changes in the direction and velocity of the wind would +have little disturbing effect, and the operator would be +required to attend only to the steering of the machine, which +was to be effected by curving the forward surface up or down. +The lateral equilibrium and the steering to right or left was to +be attained by a peculiar torsion of the main surfaces which was +equivalent to presenting one end of the wings at a greater angle +than the other. In the main frame a few changes were also made +in the details of construction and trussing employed by Mr +Chanute. The most important of these were: (1) The moving of +the forward main crosspiece of the frame to the extreme front +edge; (2) the encasing in the cloth of all crosspieces and ribs +of the surfaces; (3) a rearrangement of the wires used in +trussing the two surfaces together, which rendered it possible +to tighten all the wires by simply shortening two of them.' + +The brothers intended originally to get 200 square feet of +supporting surface for their glider, but the impossibility of +obtaining suitable material compelled them to reduce the area to +165 square feet, which, by the Lilienthal tables, admitted of +support in a wind of about twenty-one miles an hour at an angle +of three degrees. With this glider they went in the summer of I +1900 to the little settlement of Kitty Hawk, North Carolina, +situated on the strip of land dividing Albemarle Sound from the +Atlantic. Here they reckoned on obtaining steady wind, and +here, on the day that they completed the machine, they took it +out for trial as a kite with the wind blowing at between +twenty-five and thirty miles an hour. They found that in order +to support a man on it the glider required an angle nearer +twenty degrees than three, and even with the wind at thirty +miles an hour they could not get down to the planned angle of +three degrees. 'Later, when the wind was too light to support +the machine with a man on it, they tested it as a kite, working +the rudders by cords. Although they obtained satisfactory +results in this way they realised fully that actual gliding +experience was necessary before the tests could be considered +practical. + +A series of actual measurements of lift and drift of the machine +gave astonishing results. 'It appeared that the total +horizontal pull of the machine, while sustaining a weight of 52 +lbs., was only 8.5 lbs., which was less than had been previously +estimated for head resistance of the framing alone. Making +allowance for the weight carried, it appeared that the head +resistance of the framing was but little more than fifty per +cent of the amount which Mr Chanute had estimated as the head +resistance of the framing of his machine. On the other hand, it +appeared sadly deficient in lifting power as compared with the +calculated lift of curved surfaces of its size... we decided to +arrange our machine for the following year so that the depth of +curvature of its surfaces could be varied at will, and its +covering air-proofed.' + +After these experiments the brothers decided to turn to +practical gliding, for which they moved four miles to the south, +to the Kill Devil sandhills, the principal of which is slightly +over a hundred feet in height, with an inclination of nearly ten +degrees on its main north-western slope. On the day after their +arrival they made about a dozen glides, in which, although the +landings were made at a speed of more than twenty miles an hour, +no injury was sustained either by the machine or by the +operator. + +'The slope of the hill was 9.5 degrees, or a drop of one foot in +six. We found that after attaining a speed of about twenty-five +to thirty miles with reference to the wind, or ten to fifteen +miles over the ground, the machine not only glided parallel to +the slope of the hill, but greatly increased its speed, thus +indicating its ability to glide on a somewhat less angle than +9.5 degrees, when we should feel it safe to rise higher from the +surface. The control of the machine proved even better than we +had dared to expect, responding quickly to the slightest motion +of the rudder. With these glides our experiments for the year +1900 closed. Although the hours and hours of practice we had +hoped to obtain finally dwindled down to about two minutes, we +were very much pleased with the general results of the trip, +for, setting out as we did with almost revolutionary theories on +many points and an entirely untried form of machine, we +considered it quite a point to be able to return without having +our pet theories completely knocked on the head by the hard +logic of experience, and our own brains dashed out in the +bargain. Everything seemed to us to confirm the correctness of +our original opinions: (1) That practice is the key to the +secret of flying; (2) that it is practicable to assume the +horizontal position; (3) that a smaller surface set at a +negative angle in front of the main bearing surfaces, or wings, +will largely counteract the effect of the fore and aft travel of +the centre of pressure; (4) that steering up and down can be +attained with a rudder without moving the position of the +operator's body; (5) that twisting the wings so as to present +their ends to the wind at different angles is a more prompt and +efficient way of maintaining lateral equilibrium than shifting +the body of the operator.' + +For the gliding experiments of 1901 it was decided to retain the +form of the 1900 glider, but to increase the area to 308 square +feet, which, the brothers calculated, would support itself and +its operator in a wind of seventeen miles an hour with an angle +of incidence of three degrees. Camp was formed at Kitty Hawk in +the middle of July, and on July 27th the machine was completed +and tried for the first time in a wind of about fourteen miles +an hour. The first attempt resulted in landing after a glide of +only a few yards, indicating that the centre of gravity was too +far in front of the centre of pressure. By shifting his +position farther and farther back the operator finally achieved +an undulating flight of a little over 300 feet, but to obtain +this success he had to use full power of the rudder to prevent +both stalling and nose-diving. With the 1900 machine one-fourth +of the rudder action had been necessary for far better control. + +Practically all glides gave the same result, and in one the +machine rose higher and higher until it lost all headway. 'This +was the position from which Lilienthal had always found +difficulty in extricating himself, as his machine then, in spite +of his greatest exertions, manifested a tendency to dive +downward almost vertically and strike the ground head on with +frightful velocity. In this case a warning cry from the ground +caused the operator to turn the rudder to its full extent and +also to move his body slightly forward. The machine then +settled slowly to the ground, maintaining its horizontal +position almost perfectly, and landed without any injury at all. +This was very encouraging, as it showed that one of the very +greatest dangers in machines with horizontal tails had been +overcome by the use of the front rudder. Several glides later +the same experience was repeated with the same result. In the +latter case the machine had even commenced to move backward, but +was nevertheless brought safely to the ground in a horizontal +position. On the whole this day's experiments were encouraging, +for while the action of the rudder did not seem at all like that +of our 1900 machine, yet we had escaped without difficulty from +positions which had proved very dangerous to preceding +experimenters, and after less than one minute's actual practice +had made a glide of more than 300 feet, at an angle of descent +of ten degrees, and with a machine nearly twice as large as had +previously been considered safe. The trouble with its control, +which has been mentioned, we believed could be corrected when we +should have located its cause.' + +It was finally ascertained that the defect could be remedied by +trussing down the ribs of the whole machine so as to reduce the +depth of curvature. When this had been done gliding was +resumed, and after a few trials glides of 366 and 389 feet were +made with prompt response on the part of the machine, even to +small movements of the rudder. The rest of the story of the +gliding experiments of 1901 cannot be better told than in Wilbur +Wright's own words, as uttered by him in the lecture from which +the foregoing excerpts have been made. + +'The machine, with its new curvature, never failed to respond +promptly to even small movements of the rudder. The operator +could cause it to almost skim the ground, following the +undulations of its surface, or he could cause it to sail out +almost on a level with the starting point, and, passing high +above the foot of the hill, gradually settle down to the ground. +The wind on this day was blowing eleven to fourteen miles per +hour. The next day, the conditions being favourable, the +machine was again taken out for trial. This time the velocity +of the wind was eighteen to twenty-two miles per hour. At first +we felt some doubt as to the safety of attempting free flight in +so strong a wind, with a machine of over 300 square feet and a +practice of less than five minutes spent in actual flight. But +after several preliminary experiments we decided to try a glide. +The control of the machine seemed so good that we then felt no +apprehension in sailing boldly forth. And thereafter we made +glide after glide, sometimes following the ground closely and +sometimes sailing high in the air. Mr Chanute had his camera +with him and took pictures of some of these glides, several of +which are among those shown. + +'We made glides on subsequent days, whenever the conditions were +favourable. The highest wind thus experimented in was a little +over twelve metres per second--nearly twenty-seven miles per +hour. + +It had been our intention when building the machine to do the +larger part of the experimenting in the following manner:--When +the wind blew seventeen miles an hour, or more, we would attach +a rope to the machine and let it rise as a kite with the +operator upon it. When it should reach a proper height the +operator would cast off the rope and glide down to the ground +just as from the top of a hill. In this way we would be saved +the trouble of carrying the machine uphill after each glide, and +could make at least ten glides in the time required for one in +the other way. But when we came to try it, we found that a wind +of seventeen miles, as measured by Richards' anemometer, instead +of sustaining the machine with its operator, a total weight of +240 lbs., at an angle of incidence of three degrees, in reality +would not sustain the machine alone--100 lbs.--at this angle. +Its lifting capacity seemed scarcely one third of the calculated +amount. In order to make sure that this was not due to the +porosity of the cloth, we constructed two small experimental +surfaces of equal size, one of which was air-proofed and the +other left in its natural state; but we could detect no +difference in their lifting powers. For a time we were led to +suspect that the lift of curved surfaces very little exceeded +that of planes of the same size, but further investigation and +experiment led to the opinion that (1) the anemometer used by us +over-recorded the true velocity of the wind by nearly 15 per +cent; (2) that the well-known Smeaton co-efficient of .005 V +squared for the wind pressure at 90 degrees is probably too +great by at least 20 per cent; (3) that Lilienthal's estimate +that the pressure on a curved surface having an angle of +incidence of 3 degrees equals .545 of the pressure at go degrees +is too large, being nearly 50 per cent greater than very recent +experiments of our own with a pressure testing-machine indicate; +(4) that the superposition of the surfaces somewhat reduced the +lift per square foot, as compared with a single surface of equal +area. + +'In gliding experiments, however, the amount of lift is of less +relative importance than the ratio of lift to drift, as this +alone decides the angle of gliding descent. In a plane the +pressure is always perpendicular to the surface, and the ratio +of lift to drift is therefore the same as that of the cosine to +the sine of the angle of incidence. But in curved surfaces a +very remarkable situation is found. The pressure, instead of +being uniformly normal to the chord of the arc, is usually +inclined considerably in front of the perpendicular. The result +is that the lift is greater and the drift less than if the +pressure were normal. Lilienthal was the first to discover this +exceedingly important fact, which is fully set forth in his +book, Bird Flight the Basis of the Flying Art, but owing to some +errors in the methods he used in making measurements, question +was raised by other investigators not only as to the accuracy of +his figures, but even as to the existence of any tangential +force at all. Our experiments confirm the existence of this +force, though our measurements differ considerably from those of +Lilienthal. While at Kitty Hawk we spent much time in measuring +the horizontal pressure on our unloaded machine at various +angles of incidence. We found that at 13 degrees the horizontal +pressure was about 23 lbs. This included not only the drift +proper, or horizontal component of the pressure on the side of +the surface, but also the head resistance of the framing as +well. The weight of the machine at the time of this test was +about 108 lbs. Now, if the pressure had been normal to the +chord of the surface, the drift proper would have been to the +lift (108 lbs.) as the sine of 13 degrees is to the cosine of 13 +degrees, or .22 X 108/.97 = 24+ lbs.; but this slightly exceeds +the total pull of 23 pounds on our scales. Therefore it is +evident that the average pressure on the surface, instead of +being normal to the chord, was so far inclined toward the front +that all the head resistance of framing and wires used in the +construction was more than overcome. In a wind of fourteen +miles per hour resistance is by no means a negligible factor, so +that tangential is evidently a force of considerable value. In +a higher wind, which sustained the machine at an angle of 10 +degrees the pull on the scales was 18 lbs. With the pressure +normal to the chord the drift proper would have been 17 X 98/.98. +The travel of the centre of pressure made it necessary to put +sand on the front rudder to bring the centres of gravity and +pressure into coincidence, consequently the weight of the +machine varied from 98 lbs. to 108 lbs. in the different tests)= +17 lbs., so that, although the higher wind velocity must have +caused an increase in the head resistance, the tangential force +still came within 1 lb. of overcoming it. After our return +from Kitty Hawk we began a series of experiments to accurately +determine the amount and direction of the pressure produced on +curved surfaces when acted upon by winds at the various angles +from zero to 90 degrees. These experiments are not yet +concluded, but in general they support Lilienthal in the claim +that the curves give pressures more favourable in amount and +direction than planes; but we find marked differences in the +exact values, especially at angles below 10 degrees. We were +unable to obtain direct measurements of the horizontal pressures +of the machine with the operator on board, but by comparing the +distance travelled with the vertical fall, it was easily +calculated that at a speed of 24 miles per hour the total +horizontal resistances of our machine, when bearing the +operator, amounted to 40 lbs., which is equivalent to about +2 1/3 horse-power. It must not be supposed, however, that a +motor developing this power would be sufficient to drive a +man-bearing machine. The extra weight of the motor would +require either a larger machine, higher speed, or a greater +angle of incidence in order to support it, and therefore more +power. It is probable, however, that an engine of 6 +horse-power, weighing 100 lbs. would answer the purpose. Such +an engine is entirely practicable. Indeed, working motors of +one-half this weight per horse-power (9 lbs. per horse-power) +have been constructed by several different builders. Increasing +the speed of our machine from 24 to 33 miles per hour reduced +the total horizontal pressure from 40 to about 35 lbs. This was +quite an advantage in gliding, as it made it possible to sail +about 15 per cent farther with a given drop. However, it would +be of little or no advantage in reducing the size of the motor +in a power-driven machine, because the lessened thrust would be +counterbalanced by the increased speed per minute. Some years +ago Professor Langley called attention to the great economy of +thrust which might be obtained by using very high speeds, and +from this many were led to suppose that high speed was essential +to success in a motor-driven machine. But the economy to which +Professor Langley called attention was in foot pounds per mile +of travel, not in foot pounds per minute. It is the foot pounds +per minute that fixes the size of the motor. The probability is +that the first flying machines will have a relatively low speed, +perhaps not much exceeding 20 miles per hour, but the problem of +increasing the speed will be much simpler in some respects than +that of increasing the speed of a steamboat; for, whereas in the +latter case the size of the engine must increase as the cube of +the speed, in the flying machine, until extremely high speeds +are reached, the capacity of the motor increases in less than +simple ratio; and there is even a decrease in the fuel per mile +of travel. In other words, to double the speed of a steamship +(and the same is true of the balloon type of airship) eight +times the engine and boiler capacity would be required, and four +times the fuel consumption per mile of travel: while a flying +machine would require engines of less than double the size, and +there would be an actual decrease in the fuel consumption per +mile of travel. But looking at the matter conversely, the great +disadvantage of the flying machine is apparent; for in the +latter no flight at all is possible unless the proportion of +horse-power to flying capacity is very high; but on the other +hand a steamship is a mechanical success if its ratio of +horse-power to tonnage is insignificant. A flying machine that +would fly at a speed of 50 miles per hour with engines of 1,000 +horse-power would not be upheld by its wings at all at a speed +of less than 25 miles an hour, and nothing less than 500 +horse-power could drive it at this speed. But a boat which +could make 40 miles an hour with engines of 1,000 horse-power +would still move 4 miles an hour even if the engines were +reduced to 1 horse-power. The problems of land and water travel +were solved in the nineteenth century, because it was possible +to begin with small achievements, and gradually work up to our +present success. The flying problem was left over to the +twentieth century, because in this case the art must be highly +developed before any flight of any considerable duration at all +can be obtained. + +'However, there is another way of flying which requires no +artificial motor, and many workers believe that success will +come first by this road. I refer to the soaring flight, by +which the machine is permanently sustained in the air by the +same means that are employed by soaring birds. They spread +their wings to the wind, and sail by the hour, with no +perceptible exertion beyond that required to balance and steer +themselves. What sustains them is not definitely known, though +it is almost certain that it is a rising current of air. But +whether it be a rising current or something else, it is as well +able to support a flying machine as a bird, if man once learns +the art of utilising it. In gliding experiments it has long been +known that the rate of vertical descent is very much retarded, +and the duration of the flight greatly prolonged, if a strong +wind blows UP the face of the hill parallel to its surface. Our +machine, when gliding in still air, has a rate of vertical +descent of nearly 6 feet per second, while in a wind blowing 26 +miles per hour up a steep hill we made glides in which the rate +of descent was less than 2 feet per second. And during the larger +part of this time, while the machine remained exactly in the +rising current, THERE WAS NO DESCENT AT ALL, BUT EVEN A SLIGHT +RISE. If the operator had had sufficient skill to keep himself +from passing beyond the rising current he would have been +sustained indefinitely at a higher point than that from which he +started. The illustration shows one of these very slow glides at +a time when the machine was practically at a standstill. The +failure to advance more rapidly caused the photographer some +trouble in aiming, as you will perceive. In looking at this +picture you will readily understand that the excitement of +gliding experiments does not entirely cease with the breaking up +of camp. In the photographic dark-room at home we pass moments +of as thrilling interest as any in the field, when the image +begins to appear on the plate and it is yet an open question +whether we have a picture of a flying machine or merely a patch +of open sky. These slow glides in rising current probably hold +out greater hope of extensive practice than any other method +within man's reach, but they have the disadvantage of requiring +rather strong winds or very large supporting surfaces. However, +when gliding operators have attained greater skill, they can with +comparative safety maintain themselves in the air for hours at a +time in this way, and thus by constant practice so increase +their knowledge and skill that they can rise into the higher air +and search out the currents which enable the soaring birds to +transport themselves to any desired point by first rising in a +circle and then sailing off at a descending angle. This +illustration shows the machine, alone, flying in a wind of 35 +miles per hour on the face of a steep hill, 100 feet high. It +will be seen that the machine not only pulls upward, but also +pulls forward in the direction from which the wind blows, thus +overcoming both gravity and the speed of the wind. We tried the +same experiment with a man on it, but found danger that the +forward pull would become so strong, that the men holding the +ropes would be dragged from their insecure foothold on the slope +of the hill. So this form of experimenting was discontinued +after four or five minutes' trial. + +'In looking over our experiments of the past two years, with +models and full-size machines, the following points stand out +with clearness:-- + +'1. That the lifting power of a large machine, held stationary +in a wind at a small distance from the earth, is much less than +the Lilienthal table and our own laboratory experiments would +lead us to expect. When the machine is moved through the air, +as in gliding, the discrepancy seems much less marked. + +'2. That the ratio of drift to lift in well-shaped surfaces is +less at angles of incidence of 5 degrees to 12 degrees than at +an angle of 3 degrees. + +'3. That in arched surfaces the centre of pressure at 90 +degrees is near the centre of the surface, but moves slowly +forward as the angle becomes less, till a critical angle varying +with the shape and depth of the curve is reached, after which it +moves rapidly toward the rear till the angle of no lift is +found. + +'4. That with similar conditions large surfaces may be +controlled with not much greater difficulty than small ones, if +the control is effected by manipulation of the surfaces +themselves, rather than by a movement of the body of the +operator. + +'5. That the head resistances of the framing can be brought to +a point much below that usually estimated as necessary. + +'6. That tails, both vertical and horizontal, may with safety +be eliminated in gliding and other flying experiments. + +'7. That a horizontal position of the operator's body may be +assumed without excessive danger, and thus the head resistance +reduced to about one-fifth that of the upright position. + +'8. That a pair of superposed, or tandem surfaces, has less +lift in proportion to drift than either surface separately, even +after making allowance for weight and head resistance of the +connections.' + +Thus, to the end of the 1901 experiments, Wilbur Wright provided +a fairly full account of what was accomplished; the record shows +an amount of patient and painstaking work almost beyond +belief--it was no question of making a plane and launching it, +but a business of trial and error, investigation and tabulation +of detail, and the rejection time after time of previously +accepted theories, till the brothers must have felt the the +solid earth was no longer secure, at times. Though it was +Wilbur who set down this and other records of the work done, +yet the actual work was so much Orville's as his brother's that +no analysis could separate any set of experiments and say that +Orville did this and Wilbur that--the two were inseparable. On +this point Griffith Brewer remarked that 'in the arguments, if +one brother took one view, the other brother took the opposite +view as a matter of course, and the subject was thrashed to +pieces until a mutually acceptable result remained. I have +often been asked since these pioneer days, "Tell me, Brewer, who +was really the originator of those two?" In reply, I used +first to say, "I think it was mostly Wilbur," and later, +when I came to know Orville better, I said, "The thing could not +have been without Orville." Now, when asked, I have to say, " I +don't know," and I feel the more I think of it that it was only +the wonderful combination of these two brothers, who devoted +their lives together or this common object, that made the +discovery of the art of flying possible.' + +Beyond the 1901 experiments in gliding, the record grows more +scrappy, less detailed. It appears that once power-driven +flight had been achieved, the brothers were not so willing to +talk as before; considering the amount of work that they put in, +there could have been little time for verbal description +of that work--as already remarked, their tables still stand for +the designer and experimenter. The end of the 1901 experiments +left both brothers somewhat discouraged, though they had +accomplished more than any others. 'Having set out with +absolute faith in the existing scientific data, we ere driven to +doubt one thing after another, finally, after two years of +experiment, we cast it all aside, and decided to rely entirely +on our own investigations. Truth and error were everywhere so +in,timately mixed as to be indistinguishable.... We had taken up +aeronautics as a sport. We reluctantly entered upon the +scientific side of it.' + +Yet, driven thus to the more serious aspect of the work, they +found in the step its own reward, for the work of itself drew +them on and on, to the construction of measuring machines for +the avoidance of error, and to the making of series after series +of measurements, concerning which Wilbur wrote in 1908 (in the +Century Magazine) that 'after making preliminary measurements on +a great number of different shaped surfaces, to secure a general +understanding of the subject, we began systematic measurements +of standard surfaces, so varied in design as to bring out the +underlying causes of differences noted in their pressures. +Measurements were tabulated on nearly fifty of these at all +angles from zero to 45 degrees, at intervals of 2 1/2 degrees. +Measurements were also secured showing the effects on each other +when surfaces are superposed, or when they follow one another. + +'Some strange results were obtained. One surface, with a heavy +roll at the front edge, showed the same lift for all angles from +7 1/2 to 45 degrees. This seemed so anomalous that we were +almost ready to doubt our own measurements, when a simple test +was suggested. A weather vane, with two planes attached to the +pointer at an angle of 80 degrees with each other, was made. +According to our table, such a vane would be in unstable +equilibrium when pointing directly into the wind, for if by +chance the wind should happen to strike one plane at 39 degrees +and the other at 41 degrees, the plane with the smaller angle +would have the greater pressure and the pointer would be turned +still farther out of the course of the wind until the two vanes +again secured equal pressures, which would be at approximately +30 and 50 degrees. But the vane performed in this very manner. +Further corroboration of the tables was obtained in experiments +with the new glider at Kill Devil Hill the next season. + +'In September and October, 1902 nearly 1,000 gliding flights +were made, several of which covered distances of over 600 feet. +Some, made against a wind of 36 miles an hour, gave proof of the +effectiveness of the devices for control. With this machine, in +the autumn of 1903, we made a number of flights in which we +remained in the air for over a minute, often soaring for a +considerable time in one spot, without any descent at all. +Little wonder that our unscientific assistant should think the +only thing needed to keep it indefinitely in the air would be a +coat of feathers to make it light! ' + +It was at the conclusion of these experiments of 1903 that the +brothers concluded they had obtained sufficient data from their +thousands of glides and multitude of calculations to permit of +their constructing and making trial of a power-driven machine. +The first designs got out provided for a total weight of 600 +lbs., which was to include the weight of the motor and the +pilot; but on completion it was found that there was a surplus +of power from the motor, and thus they had 150 lbs. weight to +allow for strengthening wings and other parts. + +They came up against the problem to which Riach has since +devoted so much attention, that of propeller design. 'We had +thought of getting the theory of the screw-propeller from the +marine engineers, and then, by applying our table of +air-pressures to their formulae, of designing air-propellers +suitable for our uses. But, so far as we could learn, the +marine engineers possessed only empirical formulae, and the +exact action of the screw propeller, after a century of use, was +still very obscure. As we were not in a position to undertake a +long series of practical experiments to discover a propeller +suitable for our machine, it seemed necessary to obtain such a +thorough understanding of the theory of its reactions as would +enable us to design them from calculation alone. What at first +seemed a simple problem became more complex the longer we +studied it. With the machine moving forward, the air flying +backward, the propellers turning sidewise, and nothing standing +still, it seemed impossible to find a starting point from which +to trace the various simultaneous reactions. Contemplation of +it was confusing. After long arguments we often found ourselves +in the ludicrous position of each having been converted to the +other's side, with no more agreement than when the discussion +began. + +'It was not till several months had passed, and every phase of +the problem had been thrashed over and over, that the various +reactions began to untangle themselves. When once a clear +understanding had been obtained there was no difficulty in +designing a suitable propeller, with proper diameter, pitch, and +area of blade, to meet the requirements of the flier. High +efficiency in a screw-propeller is not dependent upon any +particular or peculiar shape, and there is no such thing as a +"best" screw. A propeller giving a high dynamic efficiency when +used upon one machine may be almost worthless when used upon +another. The propeller should in every case be designed to meet +the particular conditions of the machine to which it is to be +applied. Our first propellers, built entirely from calculation, +gave in useful work 66 per cent of the power expended. This was +about one-third more than had been secured by Maxim or Langley.' + +Langley had made his last attempt with the 'aerodrome,' and his +splendid failure but a few days before the brothers made their +first attempt at power-driven aeroplane flight. On December +17th, 1903, the machine was taken out; in addition to Wilbur and +Orville Wright, there were present five spectators: Mr A. D. +Etheridge, of the Kil1 Devil life-saving station; Mr W. S.Dough, +Mr W. C. Brinkley, of Manteo; Mr John Ward, of Naghead, and Mr +John T. Daniels.[*] A general invitation had been given to +practically all the residents in the vicinity, but the Kill +Devil district is a cold area in December, and history had +recorded so many experiments in which machines had failed to +leave the ground that between temperature and scepticism only +these five risked a waste of their time. + +[*] This list is as given by Wilbur Wright himself. + +And these five were in at the greatest conquest man had made +since James Watt evolved the steam engine --perhaps even a +greater conquest than that of Watt. Four flights in all were +made; the first lasted only twelve seconds, 'the first in the +history of the world in which a machine carrying a man had +raised itself into the air by its own power in free flight, had +sailed forward on a level course without reduction of speed, and +had finally landed without being wrecked,' said Wilbur +Wright concerning the achievement.[*] The next two flights were +slightly longer, and the fourth and last of the day was one +second short of the complete minute; it was made into the teeth +of a 20 mile an hour wind, and the distance travelled was 852 +feet. + +[*] Century Magazine, September, 1908. + +This bald statement of the day's doings is as Wilbur Wright +himself has given it, and there is in truth nothing more to say; +no amount of statement could add to the importance of the +achievement, and no more than the bare record is necessary. The +faith that had inspired the long roll of pioneers, from da Vinci +onward, was justified at last. + +Having made their conquest, the brothers took the machine back +to camp, and, as they thought, placed it in safety. Talking +with the little group of spectators about the flights, they +forgot about the machine, and then a sudden gust of wind struck +it. Seeing that it was being overturned, all made a rush toward +it to save it, and Mr Daniels, a man of large proportions, was +in some way lifted off his feet, falling between the planes. +The machine overturned fully, and Daniels was shaken like a die +in a cup as the wind rolled the machine over and over--he came +out at the end of his experience with a series of bad bruises, +and no more, but the damage done to the machine by the accident +was sufficient to render it useless for further experiment that +season. + +A new machine, stronger and heavier, was constructed by the +brothers, and in the spring of 1904 they began experiments again +at Sims Station, eight miles to the east of Dayton, their home +town. Press representatives were invited for the first trial, +and about a dozen came--the whole gathering did not number more +than fifty people. 'When preparations had been concluded,' +Wilbur Wright wrote of this trial, 'a wind of only three or four +miles an hour was blowing--insufficient for starting on so short +a track --but since many had come a long way to see the machine +in action, an attempt was made. To add to the other difficulty, +the engine refused to work properly. The machine, after running +the length of the track, slid off the end without rising into +the air at all. Several of the newspaper men returned next day +but were again disappointed. The engine performed badly, and +after a glide of only sixty feet the machine again came to the +ground. Further trial was postponed till the motor could be put +in better running condition. The reporters had now, no doubt, +lost confidence in the machine, though their reports, in +kindness, concealed it. Later, when they heard that we were +making flights of several minutes' duration, knowing that longer +flights had been made with airships, and not knowing any +essential difference between airships and flying machines, they +were but little interested. + +'We had not been flying long in 1904 before we found that the +problem of equilibrium had not as yet been entirely solved. +Sometimes, in making a circle, the machine would turn over +sidewise despite anything the operator could do, although, under +the same conditions in ordinary straight flight it could have +been righted in an instant. In one flight, in 1905, while +circling round a honey locust-tree at a height of about 50 feet, +the machine suddenly began to turn up on one wing, and took a +course toward the tree. The operator, not relishing the idea of +landing in a thorn tree, attempted to reach the ground. The +left wing, however, struck the tree at a height of 10 or 12 feet +from the ground and carried away several branches; but the +flight, which had already covered a distance of six miles, was +continued to the starting point. + +'The causes of these troubles--too technical for explanation +here--were not entirely overcome till the end of September, +1905. The flights then rapidly increased in length, till +experiments were discontinued after October 5 on account of the +number of people attracted to the field. Although made on a +ground open on every side, and bordered on two sides by +much-travelled thoroughfares, with electric cars passing every +hour, and seen by all the people living in the neighbourhood for +miles around, and by several hundred others, yet these flights +have been made by some newspapers the subject of a great +"mystery." ' + +Viewing their work from the financial side, the two brothers +incurred but little expense in the earlier gliding experiments, +and, indeed, viewed these only as recreation, limiting their +expenditure to that which two men might spend on any hobby. +When they had once achieved successful power-driven flight, they +saw the possibilities of their work, and abandoned such other +business as had engaged their energies, sinking all their +capital in the development of a practical flying machine. +Having, in 1905, improved their designs to such an extent that +they could consider their machine a practical aeroplane, they +devoted the years 1906 and 1907 to business negotiations and to +the construction of new machines, resuming flying experiments in +May of 1908 in order to test the ability of their machine to +meet the requirements of a contract they had made with the +United States Government, which required an aeroplane capable of +carrying two men, together with sufficient fuel supplies for a +flight of 125 miles at 40 miles per hour. Practically similar +to the machine used in the experiments of 1905, the contract +aeroplane was fitted with a larger motor, and provision was made +for seating a passenger and also for allowing of the operator +assuming a sitting position, instead of lying prone. + +Before leaving the work of the brothers to consider contemporary +events, it may be noted that they claimed--with justice--that +they were first to construct wings adjustable to different +angles of incidence on the right and left side in order to +control the balance of an aeroplane; the first to attain lateral +balance by adjusting wing-tips to respectively different angles +of incidence on the right and left sides, and the first to use a +vertical vane in combination with wing-tips, adjustable to +respectively different angles of incidence, in balancing and +steering an aeroplane. They were first, too, to use a movable +vertical tail, in combination with wings adjustable to different +angles of incidence, in controlling the balance and direction of +an aeroplane.[*] + +[*]Aeronautical Journal, No. 79. + +A certain Henry M. Weaver, who went to see the work of the +brothers, writing in a letter which was subsequently read before +the Aero Club de France records that he had a talk in 1905 with +the farmer who rented the field in which the Wrights made their +flights.' On October 5th (1905) he was cutting corn in the next +field east, which is higher ground. When he noticed the +aeroplane had started on its flight he remarked to his helper: +"Well, the boys are at it again," and kept on cutting corn, at +the same time keeping an eye on the great white form rushing +about its course. "I just kept on shocking corn," he continued, +"until I got down to the fence, and the durned thing was still +going round. I thought it would never stop." ' + +He was right. The brothers started it, and it will never stop. + +Mr Weaver also notes briefly the construction of the 1905 Wright +flier. 'The frame was made of larch wood-from tip to tip of the +wings the dimension was 40 feet. The gasoline motor--a special +construction made by them--much the same, though, as the motor +on the Pope-Toledo automobile--was of from 12 to 15 horse-power. +The motor weighed 240 lbs. The frame was covered with ordinary +muslin of good quality. No attempt was made to lighten the +machine; they simply built it strong enough to stand the shocks. +The structure stood on skids or runners, like a sleigh. These +held the frame high enough from the ground in alighting to +protect the blades of the propeller. Complete with motor, the +machine weighed 925 lbs. + + + +XII. THE FIRST YEARS OF CONQUEST + +It is no derogation of the work accomplished by the Wright +Brothers to say that they won the honour of the first +power-propelled flights in a heavier-than-air machine only by a +short period. In Europe, and especially in France, independent +experiment was being conducted by Ferber, by Santos-Dumont, and +others, while in England Cody was not far behind the other +giants of those days. The history of the early years of +controlled power flights is a tangle of half-records; there were +no chroniclers, only workers, and much of what was done goes +unrecorded perforce, since it was not set down at the time. + +Before passing to survey of those early years, let it be set +down that in 1907, when the Wright Brothers had proved the +practicability of their machines, negotiations were entered into +between the brothers and the British War office. On April 12th +1907, the apostle of military stagnation, Haldane, then War +Minister, put an end to the negotiations by declaring that 'the +War office is not disposed to enter into relations at present +with any manufacturer of aeroplanes' The state of the British +air service in 1914 at the outbreak of hostilities, is eloquent +regarding the pursuance of the policy which Haldane initiated. + +'If I talked a lot,' said Wilbur Wright once, 'I should be like +the parrot, which is the bird that speaks most and flies least.' +That attitude is emblematic of the majority of the early fliers, +and because of it the record of their achievements is incomplete +to-day. Ferber, for instance, has left little from which to +state what he did, and that little is scattered through various +periodicals, scrappily enough. A French army officer, Captain +Ferber was experimenting with monoplane and biplane gliders at +the beginning of the century-his work was contemporary with that +of the Wrights. He corresponded both with Chanute and with the +Wrights, and in the end he was commissioned by the French +Ministry of War to undertake the journey to America in order to +negotiate with the Wright Brothers concerning French rights in +the patents they had acquired, and to study their work at first +hand. + +Ferber's experiments in gliding began in 1899 at the Military +School at Fountainebleau, with a canvas glider of some 80 square +feet supporting surface, and weighing 65 lbs. Two years later +he constructed a larger and more satisfactory machine, with +which he made numerous excellent glides. Later, he constructed +an apparatus which suspended a plane from a long arm which swung +on a tower, in order that experiments might be carried out +without risk to the experimenter, and it was not until 1905 that +he attempted power-driven free flight. He took up the Voisin +design of biplane for his power-driven flights, and virtually +devoted all his energies to the study of aeronautics. His book, +Aviation, its Dawn and Development, is a work of scientific +value--unlike many of his contemporaries, Ferber brought to the +study of the problems of flight a trained mind, and he was +concerned equally with the theoretical problems of aeronautics +and the practical aspects of the subject. + +After Bleriot's successful cross-Channel flight, it was proposed +to offer a prize of L1,000 for the feat which C. S. Rolls +subsequently accomplished (starting from the English side of the +Channel), a flight from Boulogne to Dover and back; in place of +this, however, an aviation week at Boulogne was organised, but, +although numerous aviators were invited to compete, the +condition of the flying grounds was such that no competitions +took place. Ferber was virtually the only one to do any flying +at Boulogne, and at the outset he had his first accident; after +what was for those days a good flight, he made a series of +circles with his machine, when it suddenly struck the ground, +being partially wrecked. Repairs were carried out, and Ferber +resumed his exhibition flights, carrying on up to Wednesday, +September 22nd, 1909. On that day he remained in the air for +half an hour, and, as he was about to land, the machine struck a +mound of earth and overturned, pinning Ferber under the weight +of the motor. After being extricated, Ferber seemed to show +little concern at the accident, but in a few minutes he +complained of great pain, when he was conveyed to the ambulance +shed on the ground. + +'I was foolish,' he told those who were with him there. 'I was +flying too low. It was my own fault and it will be a severe +lesson to me. I wanted to turn round, and was only five metres +from the ground.' A little after this, he got up from the couch +on which he had been placed, and almost immediately collapsed, +dying five minutes later. + +Ferber's chief contemporaries in France were Santos-Dumont, of +airship fame, Henri and Maurice Farman, Hubert Latham, Ernest +Archdeacon, and Delagrange. These are names that come at once to +mind, as does that of Bleriot, who accomplished the second great +feat of power-driven flight, but as a matter of fact the years +1903-10 are filled with a little host of investigators and +experimenters, many of whom, although their names do not survive +to any extent, are but a very little way behind those mentioned +here in enthusiasm and devotion. Archdeacon and Gabriel Voisin, +the former of whom took to heart the success achieved by the +Wright Brothers, co-operated in experiments in gliding. +Archdeacon constructed a glider in box-kite fashion, and Voisin +experimented with it on the Seine, the glider being towed by a +motorboat to attain the necessary speed. It was Archdeacon who +offered a cup for the first straight flight of 200 metres, which +was won by Santos-Dumont, and he also combined with Henri Deutsch +de la Meurthe in giving the prize for the first circular flight +of a mile, which was won by Henry Farman on January 13th, 1908. + +A history of the development of aviation in France in these, the +strenuous years, would fill volumes in itself. Bleriot was +carrying out experiments with a biplane glider on the Seine, and +Robert Esnault-Pelterie was working on the lines of the Wright +Brothers, bringing American practice to France. In America +others besides the Wrights had wakened to the possibilities of +heavier-than-air flight; Glenn Curtiss, in company with Dr +Alexander Graham Bell, with J. A. D. McCurdy, and with F. W. +Baldwin, a Canadian engineer, formed the Aerial Experiment +Company, which built a number of aeroplanes, most famous of +which were the 'June Bug,' the 'Red Wing,' and the 'White Wing.' +In 1908 the 'June Bug 'won a cup presented by the Scientific +American--it was the first prize offered in America in +connection with aeroplane flight. + +Among the little group of French experimenters in these first +years of practical flight, Santos-Dumont takes high rank. He +built his 'No. 14 bis' aeroplane in biplane form, with two +superposed main plane surfaces, and fitted it with an +eight-cylinder Antoinette motor driving a two-bladed aluminium +propeller, of which the blades were 6 feet only from tip to tip. +The total lift surface of 860 square feet was given with a +wing-span of a little under 40 feet, and the weight of the +complete machine was 353 lbs., of which the engine weighed 158 +lbs. In July of 1906 Santos-Dumont flew a distance of a few +yards in this machine, but damaged it in striking the ground; on +October 23rd of the same year he made a flight of nearly 200 +feet--which might have been longer, but that he feared a crowd +in front of the aeroplane and cut off his ignition. This may be +regarded as the first effective flight in Europe, and by it +Santos-Dumont takes his place as one of the chief--if not the +chief--of the pioneers of the first years of practical flight, +so far as Europe is concerned. + +Meanwhile, the Voisin Brothers, who in 1904 made cellular kites +for Archdeacon to test by towing on the Seine from a motor +launch, obtained data for the construction of the aeroplane +which Delagrange and Henry Farman were to use later. The Voisin +was a biplane, constructed with due regard to the designs of +Langley, Lilienthal, and other earlier experimenters--both the +Voisins and M. Colliex, their engineer, studied Lilienthal +pretty exhaustively in getting out their design, though their +own researches were very thorough as well. The weight of this +Voisin biplane was about 1,450 lbs., and its maximum speed was +some 38 to 40 miles per hour, the total supporting surface being +about 535 square feet. It differed from the Wright design in +the possession of a tail-piece, a characteristic which marked +all the French school of early design as in opposition to the +American. The Wright machine got its longitudinal stability by +means of the main planes and the elevating planes, while the +Voisin type added a third factor of stability in its sailplanes. +Further, the Voisins fitted their biplane with a wheeled +undercarriage, while the Wright machine, being fitted only with +runners, demanded a launching rail for starting. Whether a +machine should be tailless or tailed was for some long time +matter for acute controversy, which in the end was settled by +the fitting of a tail to the Wright machines-France won the +dispute by the concession. + +Henry Farman, who began his flying career with a Voisin machine, +evolved from it the aeroplane which bore his name, following the +main lines of the Voisin type fairly closely, but making +alterations in the controls, and in the design of the +undercarriage, which was somewhat elaborated, even to the +inclusion of shock absorbers. The seven-cylinder 50 horse-power +Gnome rotary engine was fitted to the Farman machine--the +Voisins had fitted an eight-cylinder Antoinette, giving 50 +horse-power at 1,100 revolutions per minute, with direct drive +to the propeller. Farman reduced the weight of the machine from +the 1,450 lbs. of the Voisins to some 1,010 lbs. or +thereabouts, and the supporting area to 450 square feet. This +machine won its chief fame with Paulhan as pilot in the famous +London to Manchester flight--it is to be remarked, too, that +Farman himself was the first man in Europe to accomplish a +flight of a mile. + +Other notable designs of these early days were the 'R.E.P.', +Esnault Pelterie's machine, and the Curtiss-Herring biplane. Of +these Esnault Pelterie's was a monoplane, designed in that form +since Esnault Pelterie had found by experiment that the wire +used in bracing offers far more resistance to the air than its +dimensions would seem to warrant. He built the wings of +sufficient strength to stand the strain of flight without +bracing wires, and dependent only for their support on the +points of attachment to the body of the machine; for the rest, +it carried its propeller in front of the planes, and both +horizontal and vertical rudders at the stern--a distinct +departure from the Wright and similar types. One wheel only was +fixed under the body where the undercarriage exists on a normal +design, but light wheels were fixed, one at the extremity of +each wing, and there was also a wheel under the tail portion of +the machine. A single lever actuated all the controls for +steering. With a supporting surface of 150 square feet the +machine weighed 946 lbs., about 6.4 lbs. per square foot of +lifting surface. + +The Curtiss biplane, as flown by Glenn Curtiss at the Rheims +meeting, was built with a bamboo framework, stayed by means of +very fine steel-stranded cables. A--then--novel feature of the +machine was the moving of the ailerons by the pilot leaning to +one side or the other in his seat, a light, tubular arm-rest +being pressed by his body when he leaned to one side or the +other, and thus operating the movement of the ailerons employed +for tilting the plane when turning. A steering-wheel fitted +immediately in front of the pilot's seat served to operate a +rear steering-rudder when the wheel was turned in either +direction, while pulling back the wheel altered the inclination +of the front elevating planes, and so gave lifting or depressing +control of the plane. + +This machine ran on three wheels before leaving the ground, a +central undercarriage wheel being fitted in front, with two more +in line with a right angle line drawn through the centre of the +engine crank at the rear end of the crank-case. The engine was +a 35 horsepower Vee design, water cooled, with overhead inlet +and exhaust valves, and Bosch high-tension magneto ignition. +The total weight of the plane in flying order was about 700 lbs. + +As great a figure in the early days as either Ferber or +Santos-Dumont was Louis Bleriot, who, as early as 1900 built a +flapping-wing model, this before ever he came to experimenting +with the Voisin biplane type of glider on the Seine. Up to 1906 +he had built four biplanes of his own design, and in March of +1907 he built his first monoplane, to wreck it only a few days +after completion in an accident from which he had a fortunate +escape. His next machine was a double monoplane, designed after +Langley's precept, to a certain extent, and this was totally +wrecked in September of 1907. His seventh machine, a +monoplane, was built within a month of this accident, and with +this he had a number of mishaps, also achieving some good +flights, including one in which he made a turn. It was wrecked +in December of 1907, whereupon he built another monoplane on +which, on July 6th, 1908, Bleriot made a flight lasting eight +and a half minutes. In October of that year he flew the machine +from Toury to Artenay and returned on it--this was just a day +after Farman's first cross-country flight--but, trying to repeat +the success five days later, Bleriot collided with a tree in a +fog and wrecked the machine past repair. Thereupon he set about +building his eleventh machine, with which he was to achieve the +first flight across the English channel. + +Henry Farman, to whom reference has already been made, was +engaged with his two brothers, Maurice and Richard, in the +motor-car business, and turned to active interest in flying in +1907, when the Voisin firm built his first biplane on the +box-kite principle. In July of 1908 he won a prize of L400 for +a flight of thirteen miles, previously having completed the +first kilometre flown in Europe with a passenger, the said +passenger being Ernest Archdeaon. In September of 1908 Farman +put up a speed record of forty miles an hour in a flight lasting +forty minutes. + +Santos-Dumont produced the famous 'Demoiselle' monoplane early +in 1909, a tiny machine in which the pilot had his seat in a +sort of miniature cage under the main plane. It was a very +fast, light little machine but was difficult to fly, and owing +to its small wingspread was unable to glide at a reasonably safe +angle. There has probably never been a cheaper flying machine +to build than the 'Demoiselle,' which could be so upset as to +seem completely wrecked, and then repaired ready for further +flight by a couple of hours' work. Santos-Dumont retained no +patent in the design, but gave it out freely to any one who +chose to build 'Demoiselles'; the vogue of the pattern was +brief, owing to the difficulty of piloting the machine. + +These were the years of records, broken almost as soon as made. +There was Farman's mile, there was the flight of the Comte de +Lambert over the Eiffel Tower, Latham's flight at Blackpool in a +high wind, the Rheims records, and then Henry Farman's flight of +four hours later in 1909, Orville Wright's height record of +1,640 feet, and Delagrange's speed record of 49.9 miles per +hour. The coming to fame of the Gnome rotary engine helped in +the making of these records to a very great extent, for in this +engine was a prime mover which gave the reliability that +aeroplane builders and pilots had been searching for, but +vainly. The Wrights and Glenn Curtiss, of course, had their own +designs of engine, but the Gnome, in spite of its lack of +economy in fuel and oil, and its high cost, soon came to be +regarded as the best power plant for flight. + +Delagrange, one of the very good pilots of the early days, +provided a curious insight to the way in which flying was +regarded, at the opening of the Juvisy aero aerodrome in May of +1909. A huge crowd had gathered for the first day's flying, and +nine machines were announced to appear, but only three were +brought out. Delagrange made what was considered an indifferent +little flight, and another pilot, one De Bischoff, attempted to +rise, but could not get his machine off the ground. Thereupon +the crowd of 30,000 people lost their tempers, broke down the +barriers surrounding the flying course, and hissed the +officials, who were quite unable to maintain order. Delagrange, +however, saved the situation by making a circuit of the course +at a height of thirty feet from the ground, which won him rounds +of cheering and restored the crowd to good humour. Possibly the +smash achieved by Rougier, the famous racing motorist, who +crashed his Voisin biplane after Delagrange had made his +circuit, completed the enjoyment of the spectators. Delagrange, +flying at Argentan in June of 1909, made a flight of four +kilometres at a height of sixty feet; for those days this was a +noteworthy performance. Contemporary with this was Hubert +Latham's flight of an hour and seven minutes on an Antoinette +monoplane; this won the adjective 'magnificent' from +contemporary recorders of aviation. + +Viewing the work of the little group of French experimenters, it +is, at this length of time from their exploits, difficult to see +why they carried the art as far as they did. There was in it +little of satisfaction, a certain measure of fame, and +practically no profit--the giants of those days got very little +for their pains. Delagrange's experience at the opening of the +Juvisy ground was symptomatic of the way in which flight was +regarded by the great mass of people--it was a sport, and +nothing more, but a sport without the dividends attaching to +professional football or horse-racing. For a brief period, +after the Rheims meeting, there was a golden harvest to be +reaped by the best of the pilots. Henry Farman asked L2,000 for +a week's exhibition flying in England, and Paulhan asked half +that sum, but a rapid increase in the number of capable pilots, +together with the fact that most flying meetings were financial +failures, owing to great expense in organisation and the +doubtful factor of the weather, killed this goose before many +golden eggs had been gathered in by the star aviators. Besides, +as height and distance records were broken one after another, it +became less and less necessary to pay for entrance to an +aerodrome in order to see a flight--the thing grew too big for a +mere sports ground. + +Long before Rheims and the meeting there, aviation had grown too +big for the chronicling of every individual effort. In that +period of the first days of conquest of the air, so much was +done by so many whose names are now half-forgotten that it is +possible only to pick out the great figures and make brief +reference to their achievements and the machines with which they +accomplished so much, pausing to note such epoch-making events +as the London-Manchester flight, Bleriot's Channel crossing, and +the Rheims meeting itself, and then passing on beyond the days +of individual records to the time when the machine began to +dominate the man. This latter because, in the early days, it +was heroism to trust life to the planes that were turned out +--the 'Demoiselle' and the Antoinette machine that Latham used +in his attempt to fly the Channel are good examples of the +flimsiness of early types--while in the later period, that of +the war and subsequently, the heroism turned itself in a +different--and nobler-direction. Design became standardised, +though not perfected. The domination of the machine may best be +expressed by contrasting the way in which machines came to be +regarded as compared with the men who flew them: up to 1909, +flying enthusiasts talked of Farman, of Bleriot, of Paulhan, +Curtiss, and of other men; later, they began to talk of the +Voisin, the Deperdussin, and even to the Fokker, the Avro, and +the Bristol type. With the standardising of the machine, the +days of the giants came to an end. + + + +XIII. FIRST FLIERS IN ENGLAND + +Certain experiments made in England by Mr Phillips seem to have +come near robbing the Wright Brothers of the honour of the first +flight; notes made by Colonel J. D. Fullerton on the Phillips +flying machine show that in 1893 the first machine was built +with a length of 25 feet, breadth of 22 feet, and height of 11 +feet, the total weight, including a 72 lb. load, being 420 lbs. +The machine was fitted with some fifty wood slats, in place of +the single supporting surface of the monoplane or two superposed +surfaces of the biplane, these slats being fixed in a steel +frame so that the whole machine rather resembled a Venetian +blind. A steam engine giving about 9 horse-power provided the +motive power for the six-foot diameter propeller which drove the +machine. As it was not possible to put a passenger in control +as pilot, the machine was attached to a central post by wire +guys and run round a circle 100 feet in diameter, the track +consisting of wooden planking 4 feet wide. Pressure of air +under the slats caused the machine to rise some two or three +feet above the track when sufficient velocity had been attained, +and the best trials were made on June 19th 1893, when at a speed +of 40 miles an hour, with a total load of 385 lbs., all the +wheels were off the ground for a distance of 2,000 feet. + +In 1904 a full-sized machine was constructed by Mr Phillips, +with a total weight, including that of the pilot, of 600 lbs. +The machine was designed to lift when it had attained a velocity +of 50 feet per second, the motor fitted giving 22 horse-power. +On trial, however, the longitudinal equilibrium was found to be +defective, and a further design was got out, the third machine +being completed in 1907. In this the wood slats were held in +four parallel container frames, the weight of the machine, +excluding the pilot, being 500 lbs. A motor similar to that +used in the 1904 machine was fitted, and the machine was +designed to lift at a velocity of about 30 miles an hour, a +seven-foot propeller doing the driving. Mr Phillips tried out +this machine in a field about 400 yards across. 'The machine +was started close to the hedge, and rose from the ground when +about 200 yards had been covered. When the machine touched the +ground again, about which there could be no doubt, owing to the +terrific jolting, it did not run many yards. When it came to +rest I was about ten yards from the boundary. Of course, I +stopped the engine before I commenced to descend.'[*] + +[*] Aeronautical Journal, July, 1908. + +S. F. Cody, an American by birth, aroused the attention not only +of the British public, but of the War office and Admiralty as +well, as early as 1905 with his man-lifting kites. In that year +a height of 1,600 feet was reached by one of these box-kites, +carrying a man, and later in the same year one Sapper Moreton, +of the Balloon Section of the Royal Engineers (the parent of the +Royal Flying Corps) remained for an hour at an altitude of 2,600 +feet. Following on the success of these kites, Cody constructed +an aeroplane which he designated a 'power kite,' which was in +reality a biplane that made the first flight in Great Britain. +Speaking before the Aeronautical Society in 1908, Cody said that +'I have accomplished one thing that I hoped for very much, that +is, to be the first man to fly in Great Britain.... I made a +machine that left the ground the first time out; not high, +possibly five or six inches only. I might have gone higher if I +wished. I made some five flights in all, and the last flight +came to grief.... On the morning of the accident I went out +after adjusting my propellers at 8 feet pitch running at 600 +(revolutions per minute). I think that I flew at about +twenty-eight miles per hour. I had 50 horsepower motor power in +the engine. A bunch of trees, a flat common above these trees, +and from this flat there is a slope goes down... to another clump +of trees. Now, these clumps of trees are a quarter of a mile +apart or thereabouts.... I was accused of doing nothing but +jumping with my machine, so I got a bit agitated and went to fly. + +I went out this morning with an easterly wind, and left the +ground at the bottom of the hill and struck the ground at the +top, a distance of 74 yards. That proved beyond a doubt that the +machine would fly--it flew uphill. That was the most talented +flight the machine did, in my opinion. Now, I turned round at +the top and started the machine and left the ground--remember, a +ten mile wind was blowing at the time. Then, 60 yards from where +the men let go, the machine went off in this direction +(demonstrating)--I make a line now where I hoped to land--to cut +these trees off at that side and land right off in here. I got +here somewhat excited, and started down and saw these trees right +in front of me. I did not want to smash my head rudder to +pieces, so I raised it again and went up. I got one wing direct +over that clump of trees, the right wing over the trees, the left +wing free; the wind, blowing with me, had to lift over these +trees. So I consequently got a false lift on the right side and +no lift on the left side. Being only about 8 feet from the tree +tops, that turned my machine up like that (demonstrating). This +end struck the ground shortly after I had passed the trees. I +pulled the steering handle over as far as I could. Then I faced +another bunch of trees right in front of me. Trying to avoid +this second bunch of trees I turned the rudder, and turned it +rather sharp. That side of the machine struck, and it crumpled +up like so much tissue paper, and the machine spun round and +struck the ground that way on, and the framework was considerably +wrecked. Now, I want to advise all aviators not to try to fly +with the wind and to cross over any big clump of earth or any +obstacle of any description unless they go square over the top of +it, because the lift is enormous crossing over anything like +that, and in coming the other way against the wind it would be +the same thing when you arrive at the windward side of the +obstacle. That is a point I did not think of, and had I thought +of it I would have been more cautious.' + +This Cody machine was a biplane with about 40 foot span, the +wings being about 7 feet in depth with about 8 feet between +upper and lower wing surfaces. 'Attached to the extremities of +the lower planes are two small horizontal planes or rudders, +while a third small vertical plane is fixed over the centre of +the upper plane.' The tail-piece and principal rudder were +fitted behind the main body of the machine, and a horizontal +rudder plane was rigged out in front, on two supporting arms +extending from the centre of the machine. The small end-planes +and the vertical plane were used in conjunction with the main +rudder when turning to right or left, the inner plane being +depressed on the turn, and the outer one correspondingly raised, +while the vertical plane, working in conjunction, assisted in +preserving stability. Two two-bladed propellers were driven by +an eight-cylinder 50 horse-power Antoinette motor. With this +machine Cody made his first flights over Laffan's plain, being +then definitely attached to the Balloon Section of the Royal +Engineers as military aviation specialist. + +There were many months of experiment and trial, after the +accident which Cody detailed in the statement given above, and +then, on May 14th, 1909, Cody took the air and made a flight of +1,200 yards with entire success. Meanwhile A. V. Roe was +experimenting at Lea Marshes with a triplane of rather curious +design the pilot having his seat between two sets of three +superposed planes, of which the front planes could be tilted and +twisted while the machine was in motion. He comes but a little +way after Cody in the chronology of early British experimenters, +but Cody, a born inventor, must be regarded as the pioneer of +the present century so far as Britain is concerned. He was +neither engineer nor trained mathematician, but he was a good +rule-of-thumb mechanic and a man of pluck and perseverance; he +never strove to fly on an imperfect machine, but made alteration +after alteration in order to find out what was improvement and +what was not, in consequence of which it was said of him that he +was 'always satisfied with his alterations.' + +By July of 1909 he had fitted an 80 horse-power motor to his +biplane, and with this he made a flight of over four miles over +Laffan's Plain on July 21st. By August he was carrying +passengers, the first being Colonel Capper of the R.E. Balloon +Section, who flew with Cody for over two miles, and on September +8th, 1909, he made a world's record cross-country flight of +over forty miles in sixty-six minutes, taking a course from +Laffan's Plain over Farnborough, Rushmoor, and Fleet, and back +to Laffan's Plain. He was one of the competitors in the 1909 +Doncaster Aviation Meeting, and in 1910 he competed at +Wolverhampton, Bournemouth, and Lanark. It was on June 7th, +1910, that he qualified for his brevet, No. 9, on the Cody +biplane. + +He built a machine which embodied all the improvements for which +he had gained experience, in 1911, a biplane with a length of +35 feet and span of 43 feet, known as the 'Cody cathedral' on +account of its rather cumbrous appearance. With this, in 1911, +he won the two Michelin trophies presented in England, completed +the Daily Mail circuit of Britain, won the Michelin +cross-country prize in 1912 and altogether, by the end of 1912, +had covered more than 7,000 miles with the machine. It was +fitted with a 120 horse-power Austro-Daimler engine, and was +characterised by an exceptionally wide range of speed--the great +wingspread gave a slow landing speed. + +A few of his records may be given: in 1910, flying at Laffan's +Plain in his biplane, fitted with a 50-60 horsepower Green +engine, on December 31st, he broke the records for distance and +time by flying 185 miles, 787 yards, in 4 hours 37 minutes. On +October 31st, 1911, he beat this record by flying for 5 hours 15 +minutes, in which period he covered 261 miles 810 yards with a 60 +horse-power Green engine fitted to his biplane. In 1912, +competing in the British War office tests of military +aeroplanes, he won the L5,000 offered by the War Office. This +was in competition with no less than twenty-five other machines, +among which were the since-famous Deperdussin, Bristol, +Flanders, and Avro types, as well as the Maurice Farman and +Bleriot makes of machine. Cody's remarkable speed range was +demonstrated in these trials, the speeds of his machine varying +between 72.4 and 48.5 miles per hour. The machine was the only +one delivered for the trials by air, and during the three hours' +test imposed on all competitors a maximum height of 5,000 feet +was reached, the first thousand feet being achieved in three and +a half minutes. + +During the summer of 1913 Cody put his energies into the +production of a large hydro-biplane, with which he intended to +win the L5,000 prize offered by the Daily Mail to the first +aviator to fly round Britain on a waterplane. This machine was +fitted with landing gear for its tests, and, while flying it +over Laffan's Plain on August 7th, 1913, with Mr W. H. B. Evans +as passenger, Cody met with the accident that cost both +him and his passenger their lives. Aviation lost a great figure +by his death, for his plodding, experimenting, and dogged +courage not only won him the fame that came to a few of the +pilots of those days, but also advanced the cause of flying very +considerably and contributed not a little to the sum of +knowledge in regard to design and construction. + +Another figure of the early days was A. V. Roe, who came from +marine engineering to the motor industry and aviation in 1905. +In 1906 he went out to Colorado, getting out drawings for the +Davidson helicopter, and in 1907 having returned to England, he +obtained highest award out of 200 entries in a model aeroplane +flying competition. From the design of this model he built a +full-sized machine, and made a first flight on it, fitted with a +24 horse-power Antoinette engine, in June of 1908 Later, he +fitted a 9 horsepower motor-cycle engine to a triplane of his +own design, and with this made a number of short flights; he got +his flying brevet on a triplane with a motor of 35 horse-power, +which, together with a second triplane, was entered for the +Blackpool aviation meeting of 1910 but was burnt in transport to +the meeting. He was responsible for the building of the first +seaplane to rise from English waters, and may be counted the +pioneer of the tractor type of biplane. In 1913 he built a +two-seater tractor biplane with 80 horse-power engine, a machine +which for some considerable time ranked as a leader of design. +Together with E. V. Roe and H. V. Roe, 'A. V.' controlled the +Avro works, which produced some of the most famous training +machines of the war period in a modification of the original 80 +horse-power tractor. The first of the series of Avro tractors +to be adopted by the military authorities was the 1912 biplane, a +two-seater fitted with 50 horsepower engine. It was the first +tractor biplane with a closed fuselage to be used for military +work, and became standard for the type. The Avro seaplane, of I +100 horse-power (a fourteen-cylinder Gnome engine was used) was +taken up by the British Admiralty in 1913. It had a length of 34 +feet and a wing-span of 50 feet, and was of the twin-float type. + +Geoffrey de Havilland, though of later rank, counts high among +designers of British machines. He qualified for his brevet as +late as February, 1911, on a biplane of his own construction, and +became responsible for the design of the BE2, the first +successful British Government biplane. On this he made a British +height record of 10,500 feet over Salisbury Plain, in August of +1912, when he took up Major Sykes as passenger. In the war +period he was one of the principal designers of fighting and +reconnaissance machines. + +F. Handley Page, who started in business as an aeroplane +builder in 1908, having works at Barking, was one of the +principal exponents of the inherently stable machine, to which +he devoted practically all his experimental work up to the +outbreak of war. The experiments were made with various +machines, both of monoplane and biplane type, and of these one +of the best was a two-seater monoplane built in 1911, while a +second was a larger machine, a biplane, built in 1913 and fitted +with a 110 horse-power Anzani engine. The war period brought out +the giant biplane with which the name of Handley Page is most +associated, the twin-engined night-bomber being a familiar +feature of the later days of the war; the four-engined bomber had +hardly had a chance of proving itself under service conditions +when the war came to an end. + +Another notable figure of the early period was 'Tommy' Sopwith, +who took his flying brevet at Brooklands in November of 1910, +and within four days made the British duration record of 108 +miles in 3 hours 12 minutes. On December 18th, 1910, he won the +Baron de Forrest prize of L4,000 for the longest flight from +England to the Continent, flying from Eastchurch to Tirlemont, +Belgium, in three hours, a distance of 161 miles. After two +years of touring in America, he returned to England and +established a flying school. In 1912 he won the first aerial +Derby, and in 1913 a machine of his design, a tractor biplane, +raised the British height record to 13,000 feet (June 16th, at +Brooklands). First as aviator, and then as designer, Sopwith has +done much useful work in aviation. + +These are but a few, out of a host who contributed to the +development of flying in this country, for, although France may +be said to have set the pace as regards development, Britain was +not far behind. French experimenters received far more +Government aid than did the early British aviators and +designers--in the early days the two were practically +synonymous, and there are many stories of the very early days at +Brooklands, where, when funds ran low, the ardent spirits +patched their trousers with aeroplane fabric and went on with +their work with Bohemian cheeriness. Cody, altering and +experimenting on Laffan's Plain, is the greatest figure of them +all, but others rank, too, as giants of the early days, before +the war brought full recognition of the aeroplane's +potentialities. + +one of the first men actually to fly in England, Mr J. C. T. +Moore-Brabazon, was a famous figure in the days of exhibition +flying, and won his reputation mainly through being first to fly +a circular mile on a machine designed and built in Great Britain +and piloted by a British subject. Moore-Brabazon's earliest +flights were made in France on a Voisin biplane in 1908, and he +brought this machine over to England, to the Aero Club grounds +at Shellness, but soon decided that he would pilot a British +machine instead. An order was placed for a Short machine, and +this, fitted with a 50-60 horse-power Green engine, was used for +the circular mile, which won a prize of L1,000 offered by the +Daily Mail, the feat being accomplished on October 30th, 1909. +Five days later, Moore-Brabazon achieved the longest flight up +to that time accomplished on a British-built machine, covering +three and a half miles. In connection with early flying in +England, it is claimed that A. V. Roe, flying 'Avro B,',' on +June 8th, 1908, was actually the first man to leave the ground, +this being at Brooklands, but in point of fact Cody antedated +him. + +No record of early British fliers could be made without the name +of C. S. Rolls, a son of Lord Llangattock, on June 2nd, 1910, +he flew across the English Channel to France, until he was duly +observed over French territory, when he returned to England +without alighting. The trip was made on a Wright biplane, and +was the third Channel crossing by air, Bleriot having made the +first, and Jacques de Lesseps the second. Rolls was first to +make the return journey in one trip. He was eventually killed +through the breaking of the tail-plane of his machine in +descending at a flying meeting at Bournemouth. The machine was +a Wright biplane, but the design of the tail-plane--which, by +the way, was an addition to the machine, and was not even +sanctioned by the Wrights--appears to have been carelessly +executed, and the plane itself was faulty in construction. The +breakage caused the machine to overturn, killing Rolls, who was +piloting it. + + + +XIV. RHEIMS, AND AFTER + +The foregoing brief--and necessarily incomplete--survey of the +early British group of fliers has taken us far beyond some of +the great events of the early days of successful flight, and it +is necessary to go back to certain landmarks in the history of +aviation, first of which is the great meeting at Rheims in 1909. +Wilbur Wright had come to Europe, and, flying at Le Mans and +Pau--it was on August 8th, 1908, that Wilbur Wright made the +first of his ascents in Europe--had stimulated public interest +in flying in France to a very great degree. Meanwhile, Orville +Wright, flying at Fort Meyer, U.S.A., with Lieutenant Selfridge +as a passenger, sustained an accident which very nearly cost him +his life through the transmission gear of the motor breaking. +Selfridge was killed and Orville Wright was severely injured--it +was the first fatal accident with a Wright machine. + +Orville Wright made a flight of over an hour on September 9th, +1908, and on December 31st of that year Wilbur flew for 2 hours +19 minutes. Thus, when the Rheims meeting was organised--more +notable because it was the first of its kind, there were already +records waiting to be broken. The great week opened on August +22nd, there being thirty entrants, including all the most famous +men among the early fliers in France. Bleriot, fresh from his +Channel conquest, was there, together with Henry Farman, +Paulhan, Curtiss, Latham, and the Comte de Lambert, first pupil +of the Wright machine in Europe to achieve a reputation as an +aviator. + +'To say that this week marks an epoch in the history of the +world is to state a platitude. Nevertheless, it is worth +stating, and for us who are lucky enough to be at Rheims during +this week there is a solid satisfaction in the idea that we are +present at the making of history. In perhaps only a few years +to come the competitions of this week may look pathetically +small and the distances and speeds may appear paltry. +Nevertheless, they are the first of their kind, and that is +sufficient.' + +So wrote a newspaper correspondent who was present at the famous +meeting, and his words may stand, being more than mere +journalism; for the great flying week which opened on August +22nd, 1909, ranks as one of the great landmarks in the history +of heavier-than-air flight. The day before the opening of the +meeting a downpour of rain spoilt the flying ground; Sunday +opened with a fairly high wind, and in a lull M. Guffroy turned +out on a crimson R.E.P. monoplane, but the wheels of his +undercarriage stuck in the mud and prevented him from rising in +the quarter of an hour allowed to competitors to get off the +ground. Bleriot, following, succeeded in covering one side of +the triangular course, but then came down through grit in the +carburettor. Latham, following him with thirteen as the number +of his machine, experienced his usual bad luck and came to earth +through engine trouble after a very short flight. Captain +Ferber, who, owing to military regulations, always flew under +the name of De Rue, came out next with his Voisin biplane, but +failed to get off the ground; he was followed by Lefebvre on a +Wright biplane, who achieved the success of the morning by +rounding the course--a distance of six and a quarter miles--in +nine minutes with a twenty mile an hour wind blowing. His +flight finished the morning. + +Wind and rain kept competitors out of the air until the evening, +when Latham went up, to be followed almost immediately by the +Comte de Lambert. Sommer, Cockburn (the only English +competitor), Delagrange, Fournier, Lefebvre, Bleriot, +Bunau-Varilla, Tissandier, Paulhan, and Ferber turned out after +the first two, and the excitement of the spectators at seeing so +many machines in the air at one time provoked wild cheering. +The only accident of the day came when Bleriot damaged his +propeller in colliding with a haycock. + +The main results of the day were that the Comte de Lambert flew +30 kilometres in 29 minutes 2 seconds; Lefebvre made the +ten-kilometre circle of the track in just a second under 9 +minutes, while Tissandier did it in 9 1/4 minutes, and Paulhan +reached a height of 230 feet. Small as these results seem to us +now, and ridiculous as may seem enthusiasm at the sight of a few +machines in the air at the same time, the Rheims Meeting remains +a great event, since it proved definitely to the whole world +that the conquest of the air had been achieved. + +Throughout the week record after record was made and broken. +Thus on the Monday, Lefebvre put up a record for rounding the +course and Bleriot beat it, to be beaten in turn by Glenn +Curtiss on his Curtiss-Herring biplane. On that day, too, +Paulhan covered 34 3/4 miles in 1 hour 6 minutes. On the next +day, Paulhan on his Voisin biplane took the air with Latham, and +Fournier followed, only to smash up his machine by striking an +eddy of wind which turned him over several times. On the +Thursday, one of the chief events was Latham's 43 miles +accomplished in 1 hour 2 minutes in the morning and his 96.5 +miles in 2 hours 13 minutes in the afternoon, the latter flight +only terminated by running out of petrol. On the Friday, the +Colonel Renard French airship, which had flown over the ground +under the pilotage of M. Kapfarer, paid Rheims a second visit; +Latham manoeuvred round the airship on his Antoinette and finally +left it far behind. Henry Farman won the Grand Prix de Champagne +on this day, covering 112 miles in 3 hours, 4 minutes, 56 +seconds, Latham being second with his 96.5 miles flight, and +Paulhan third. + +On the Saturday, Glenn Curtiss came to his own, winning the +Gordon-Bennett Cup by covering 20 kilometres in 15 minutes +50.6 seconds. Bleriot made a good second with 15 minutes 56.2 +seconds as his time, and Latham and Lefebvre were third and +fourth. Farman carried off the passenger prize by carrying two +passengers a distance of 6 miles in 10 minutes 39 seconds. On +the last day Delagrange narrowly escaped serious accident +through the bursting of his propeller while in the air, Curtiss +made a new speed record by travelling at the rate of over 50 +miles an hour, and Latham, rising to 500 feet, won the altitude +prize. + +These are the cold statistics of the meeting; at this length of +time it is difficult to convey any idea of the enthusiasm of the +crowds over the achievements of the various competitors, while +the incidents of the week, comic and otherwise, are nearly +forgotten now even by those present in this making of history. +Latham's great flight on the Thursday was rendered a breathless +episode by a downpour of rain when he had covered all but a +kilometre of the record distance previously achieved by Paulhan, +and there was wild enthusiasm when Latham flew on through the +rain until he had put up a new record and his petrol had run +out. Again, on the Friday afternoon, the Colonel Renard took +the air together with a little French dirigible, Zodiac III; +Latham was already in the air directly over Farman, who was also +flying, and three crows which turned out as rivals to the human +aviators received as much cheering for their appearance as had +been accorded to the machines, which doubtless they could not +understand. Frightened by the cheering, the crows tried to +escape from the course, but as they came near the stands, the +crowd rose to cheer again and the crows wheeled away to make a +second charge towards safety, with the same result; the crowd +rose and cheered at them a third and fourth time; between ten +and fifteen thousand people stood on chairs and tables and waved +hats and handkerchiefs at three ordinary, everyday crows. One +thoughtful spectator, having thoroughly enjoyed the funny side +of the incident, remarked that the ultimate mastery of the air +lies with the machine that comes nearest to natural flight. +This still remains for the future to settle. + +Farman's world record, which won the Grand Prix de Champagne, +was done with a Gnome Rotary Motor which had only been run on +the test bench and was fitted to his machine four hours before +he started on the great flight. His propeller had never been +tested, having only been completed the night before. The +closing laps of that flight, extending as they did into the +growing of the dusk, made a breathlessly eerie experience for +such of the spectators as stayed on to watch--and these were +many. Night came on steadily and Farman covered lap after lap +just as steadily, a buzzing, circling mechanism with something +relentless in its isolated persistency. + +The final day of the meeting provided a further record in the +quarter million spectators who turned up to witness the close of +the great week. Bleriot, turning out in the morning, made a +landing in some such fashion as flooded the carburettor and +caused it to catch fire. Bleriot himself was badly burned, +since the petrol tank burst and, in the end, only the metal +parts of the machine were left. Glenn Curtis tried to beat +Bleriot's time for a lap of the course, but failed. In the +evening, Farman and Latham went out and up in great circles, +Farman cleaving his way upward in what at the time counted for a +huge machine, on circles of about a mile diameter. His first +round took him level with the top of the stands, and, in his +second, he circled the captive balloon anchored in the middle of +the grounds. After another circle, he came down on a long glide, +when Latham's lean Antoinette monoplane went up in circles more +graceful than those of Farman. 'Swiftly it rose and swept round +close to the balloon, veered round to the hangars, and out over +to the Rheims road. Back it came high over the stands, the +people craning their necks as the shrill cry of the engine drew +nearer and nearer behind the stands. Then of a sudden, the +little form appeared away up in the deep twilight blue vault of +the sky, heading straight as an arrow for the anchored balloon. +Over it, and high, high above it went the Antoinette, seemingly +higher by many feet than the Farman machine. Then, wheeling in +a long sweep to the left, Latham steered his machine round past +the stands, where the people, their nerve-tension released on +seeing the machine descending from its perilous height of 500 +feet, shouted their frenzied acclamations to the hero of the +meeting. + +'For certainly "Le Tham," as the French call him, was the +popular hero. He always flew high, he always flew well, and his +machine was a joy to the eye, either afar off or at close +quarters. The public feeling for Bleriot is different. +Bleriot, in the popular estimation, is the man who fights +against odds, who meets the adverse fates calmly and with good +courage, and to whom good luck comes once in a while as a reward +for much labour and anguish, bodily and mental. Latham is the +darling of the Gods, to whom Fate has only been unkind in the +matter of the Channel flight, and only then because the honour +belonged to Bleriot. + +'Next to these two, the public loved most Lefebvre, the joyous, +the gymnastic. Lefebvre was the comedian of the meeting. When +things began to flag, the gay little Lefebvre would trot out to +his starting rail, out at the back of the judge's enclosure +opposite the stands, and after a little twisting of propellers +his Wright machine would bounce off the end of its starting rail +and proceed to do the most marvellous tricks for the benefit of +the crowd, wheeling to right and left, darting up and down, now +flying over a troop of the cavalry who kept the plain clear of +people and sending their horses into hysterics, anon making +straight for an unfortunate photographer who would throw himself +and his precious camera flat on the ground to escape +annihilation as Lefebvre swept over him 6 or 7 feet off the +ground. Lefebvre was great fun, and when he had once found that +his machine was not fast enough to compete for speed with the +Bleriots, Antoinettes, and Curtiss, he kept to his metier of +amusing people. The promoters of the meeting owe Lefebvre a +debt of gratitude, for he provided just the necessary comic +relief.'--(The Aero, September 7th, 1909.) + +It may be noted, in connection with the fact that Cockburn was +the only English competitor at the meeting, that the Rheims +Meeting did more than anything which had preceded it to waken +British interest in aviation. Previously, heavier-than-air +flight in England had been regarded as a freak business by the +great majority, and the very few pioneers who persevered toward +winning England a share in the conquest of the air came in for +as much derision as acclamation. Rheims altered this; it taught +the world in general, and England in particular, that a serious +rival to the dirigible balloon had come to being, and it +awakened the thinking portion of the British public to the fact +that the aeroplane had a future. + +The success of this great meeting brought about a host of +imitations of which only a few deserve bare mention since, +unlike the first, they taught nothing and achieved little. +There was the meeting at Boulogne late in September of 1909, of +which the only noteworthy event was Ferber's death. There was a +meeting at Brescia where Curtiss again took first prize for +speed and Rougier put up a world's height record of 645 feet. +The Blackpool meeting followed between 18th and 23rd of +October, 1909, forming, with the exception of Doncaster, the +first British Flying Meeting. Chief among the competitors were +Henry Farman, who took the distance prize, Rougier, Paulhan, and +Latham, who, by a flight in a high wind, convinced the British +public that the theory that flying was only possible in a calm +was a fallacy. A meeting at Doncaster was practically +simultaneous with the Blackpool week; Delagrange, Le Blon, +Sommer, and Cody were the principal figures in this event. It +should be added that 130 miles was recorded as the total flown +at Doncaster, while at Blackpool only 115 miles were flown. +Then there were Juvisy, the first Parisian meeting, +Wolverhampton, and the Comte de Lambert's flight round the +Eiffel Tower at a height estimated at between 1,200 and 1,300 +feet. This may be included in the record of these aerial +theatricals, since it was nothing more. + +Probably wakened to realisation of the possibilities of the +aeroplane by the Rheims Meeting, Germany turned out its first +plane late in 1909. It was known as the Grade monoplane, and +was a blend of the Bleriot and Santos-Dumont machines, with a +tail suggestive of the Antoinette type. The main frame took the +form of a single steel tube, at the forward end of which was +rigged a triangular arrangement carrying the pilot's seat and +the landing wheels underneath, with the wing warping wires and +stays above. The sweep of the wings was rather similar to the +later Taube design, though the sweep back was not so pronounced, +and the machine was driven by a four-cylinder, 20 horse-power, +air-cooled engine which drove a two-bladed tractor propeller. +In spite of Lilienthal's pioneer work years before, this was the +first power-driven German plane which actually flew. + +Eleven months after the Rheims meeting came what may be reckoned +the only really notable aviation meeting on English soil, in the +form of the Bournemouth week, July 10th to 16th, 1910. This +gathering is noteworthy mainly in view of the amazing advance +which it registered on the Rheims performances. Thus, in the +matter of altitude, Morane reached 4,107 feet and Drexel came +second with 2,490 feet. Audemars on a Demoiselle monoplane made +a flight of 17 miles 1,480 yards in 27 minutes 17.2 seconds, a +great flight for the little Demoiselle. Morane achieved a speed +of 56.64 miles per hour, and Grahame White climbed to 1,000 feet +altitude in 6 minutes 36.8 seconds. Machines carrying the Gnome +engine as power unit took the great bulk of the prizes, and +British-built engines were far behind. + +The Bournemouth Meeting will always be remembered with regret +for the tragedy of C. S. Rolls's death, which took place on +the Tuesday, the second day of the meeting. The first +competition of the day was that for the landing prize; Grahame +White, Audemars, and Captain Dickson had landed with varying +luck, and Rolls, following on a Wright machine with a tail-plane +which ought never to have been fitted and was not part of the +Wright design, came down wind after a left-hand turn and turned +left again over the top of the stands in order to land up wind. +He began to dive when just clear of the stands, and had dropped +to a height of 40 feet when he came over the heads of the people +against the barriers. Finding his descent too steep, he pulled +back his elevator lever to bring the nose of the machine up, +tipping down the front end of the tail to present an almost flat +surface to the wind. Had all gone well, the nose of the machine +would have been forced up, but the strain on the tail and its +four light supports was too great; the tail collapsed, the wind +pressed down the biplane elevator, and the machine dived +vertically for the remaining 20 feet of the descent, hitting the +ground vertically and crumpling up. Major Kennedy, first to +reach the debris, found Rolls lying with his head doubled under +him on the overturned upper main plane; the lower plane had been +flung some few feet away with the engine and tanks under it. +Rolls was instantaneously killed by concussion of the brain. + +Antithesis to the tragedy was Audemars on his Demoiselle, which +was named 'The Infuriated Grasshopper.' Concerning this, it was +recorded at the time that 'Nothing so excruciatingly funny as +the action of this machine has ever been seen at any aviation +ground. The little two-cylinder engine pops away with a sound +like the frantic drawing of ginger beer corks; the machine +scutters along the ground with its tail well up; then down comes +the tail suddenly and seems to slap the ground while the front +jumps up, and all the spectators rock with laughter. The whole +attitude and the jerky action of the machine suggest a +grasshopper in a furious rage, and the impression is intensified +when it comes down, as it did twice on Wednesday, in long grass, +burying its head in the ground in its temper.'--(The Aero, July, +1910.) + +The Lanark Meeting followed in August of the same year, and with +the bare mention of this, the subject of flying meetings may he +left alone, since they became mere matters of show until there +came military competitions such as the Berlin Meeting at the end +of August, 1910, and the British War office Trials on Salisbury +Plain, when Cody won his greatest triumphs. The Berlin meeting +proved that, from the time of the construction of the first +successful German machine mentioned above, to the date of the +meeting, a good number of German aviators had qualified for +flight, but principally on Wright and Antoinette machines, though +by that time the Aviatik and Dorner German makes had taken the +air. The British War office Trials deserve separate and longer +mention. + +In 1910 in spite of official discouragement, Captain Dickson +proved the value of the aeroplane for scouting purposes by +observing movements of troops during the Military Manoeuvres on +Salisbury Plain. Lieut. Lancelot Gibbs and Robert Loraine, +the actor-aviator, also made flights over the manoeuvre area, +locating troops and in a way anticipating the formation and work +of the Royal Flying Corps by a usefulness which could not be +officially recognised. + + + +XV. THE CHANNEL CROSSING + +It may be said that Louis Bleriot was responsible for the second +great landmark in the history of successful flight. The day when +the brothers Wright succeeded in accomplishing power-driven +flight ranks as the first of these landmarks. Ader may or may +not have left the ground, but the wreckage of his 'Avion' at the +end of his experiment places his doubtful success in a different +category from that of the brothers Wright and leaves them the +first definite conquerors, just as Bleriot ranks as first +definite conqueror of the English Channel by air. + +In a way, Louis Bleriot ranks before Farman in point of time; +his first flapping-wing model was built as early as 1900, and +Voisin flew a biplane glider of his on the Seine in the very +early experimental days. Bleriot's first four machines were +biplanes, and his fifth, a monoplane, was wrecked almost +immediately after its construction. Bleriot had studied +Langley's work to a certain extent, and his sixth construction +was a double monoplane based on the Langley principle. A month +after he had wrecked this without damaging himself-- for Bleriot +had as many miraculous escapes as any of the other fliers-he +brought out number seven, a fairly average monoplane. It was in +December of 1907 after a series of flights that he wrecked this +machine, and on its successor, in July of 1908, he made a +flight of over 8 minutes. Sundry flights, more or less +successful, including the first cross-country flight from Toury +to Artenay, kept him busy up to the beginning of November, 1908, +when the wreckage in a fog of the machine he was flying sent him +to the building of 'number eleven,' the famous cross-channel +aeroplane. + +Number eleven was shown at the French Aero Show in the Grand +Palais and was given its first trials on the 18th January, 1909. +It was first fitted with a R.E.P. motor and had a lifting area +of 120 square feet, which was later increased to 150 square +feet. The framework was of oak and poplar spliced and +reinforced with piano wire; the weight of the machine was 47 +lbs. and the undercarriage weight a further 60 lbs., this +consisting of rubber cord shock absorbers mounted on two wheels. +The R.E.P. motor was found unsatisfactory, and a three-cylinder +Anzani of 105 mm. bore and 120 mm. stroke replaced it. An +accident seriously damaged the machine on June 2nd, but Bleriot +repaired it and tested it at Issy, where between June 19th and +June 23rd he accomplished flights of 8, 12, 15, 16, and 36 +minutes. On July 4th he made a 50-minute flight and on the 13th +flew from Etampes to Chevilly. + +A few further details of construction may be given: the wings +themselves and an elevator at the tail controlled the rate of +ascent and descent, while a rudder was also fitted at the tail. +The steering lever, working on a universally jointed +shaft--forerunner of the modern joystick--controlled both the +rudder and the wings, while a pedal actuated the elevator. The +engine drove a two-bladed tractor screw of 6 feet 7 inches +diameter, and the angle of incidence of the wings was 20 +degrees. Timed at Issy, the speed of the machine was given as 36 +miles an hour, and as Bleriot accomplished the Channel flight of +20 miles in 37 minutes, he probably had a slight following wind. + +The Daily Mail had offered a prize of L1,000 for the first +Cross-Channel flight, and Hubert Latham set his mind on winning +it. He put up a shelter on the French coast at Sangatte, +half-way between Calais and Cape Blanc Nez. From here he made +his first attempt to fly to England on Monday the 19th of July. +He soared to a fair height, circling, and reached an estimated +height of about 900 feet as he came over the water with every +appearance of capturing the Cross-Channel prize. The luck which +dogged his career throughout was against him, for, after he had +covered some 8 miles, his engine stopped and he came down to the +water in a series of long glides. It was discovered afterward +that a small piece of wire had worked its way into a vital part +of the engine to rob Latham of the honour he coveted. The tug +that came to his rescue found him seated on the fuselage of his +Antoinette, smoking a cigarette and waiting for a boat to take +him to the tug. It may be remarked that Latham merely assumed +his Antoinette would float in case he failed to make the English +coast; he had no actual proof. + +Bleriot immediately entered his machine for the prize and took +up his quarters at Barraques. On Sunday, July 25th, 1909, +shortly after 4 a.m., Bleriot had his machine taken out from its +shelter and prepared for flight. He had been recently injured +in a petrol explosion and hobbled out on crutches to make his +cross-Channel attempt; he made two great circles in the air to +try the machine, and then alighted. 'In ten minutes I start +for England,' he declared, and at 4.35 the motor was started up. +After a run of 100 yards, the machine rose in the air and got a +height of about 100 feet over the land, then wheeling sharply +seaward and heading for Dover. + +Bleriot had no means of telling direction, and any change of +wind might have driven him out over the North Sea, to be lost, +as were Cecil Grace and Hamel later on. Luck was with him, +however, and at 5.12 a.m. of that July Sunday, he made his +landing in the North Fall meadow, just behind Dover Castle. +Twenty minutes out from the French coast, he lost sight of the +destroyer which was patrolling the Channel, and at the same time +he was out of sight of land without compass or any other means +of ascertaining his direction. Sighting the English coast, he +found that he had gone too far to the east, for the wind +increased in strength throughout the flight, this to such an +extent as almost to turn the machine round when he came over +English soil. Profiting by Latham's experience, Bleriot had +fitted an inflated rubber cylinder a foot in diameter by 5 feet +in length along the middle of his fuselage, to render floating a +certainty in case he had to alight on the water. + +Latham in his camp at Sangatte had been allowed to sleep through +the calm of the early morning through a mistake on the part of a +friend, and when his machine was turned out--in order that he +might emulate Bleriot, although he no longer hoped to make the +first flight, it took so long to get the machine ready and +dragged up to its starting-point that there was a 25 mile an +hour wind by the time everything was in readiness. Latham was +anxious to make the start in spite of the wind, but the +Directors of the Antoinette Company refused permission. It was +not until two days later that the weather again became +favourable, and then with a fresh machine, since the one on +which he made his first attempt had been very badly damaged in +being towed ashore, he made a circular trial flight of about 5 +miles. In landing from this, a side gust of wind drove the nose +of the machine against a small hillock, damaging both propeller +blades and chassis, and it was not until evening that the damage +was repaired. + +French torpedo boats were set to mark the route, and Latham set +out on his second attempt at six o'clock. Flying at a height of +200 feet, he headed over the torpedo boats for Dover and seemed +certain of making the English coast, but a mile and a half out +from Dover his engine failed him again, and he dropped to the +water to be picked up by the steam pinnace of an English warship +and put aboard the French destroyer Escopette. + +There is little to choose between the two aviators for courage +in attempting what would have been considered a foolhardy feat a +year or two before. Bleriot's state, with an abscess in the +burnt foot which had to control the elevator of his machine, +renders his success all the more remarkable. His machine was +exhibited in London for a time, and was afterwards placed in the +Conservatoire des Arts et Metiers, while a memorial in stone, +copying his monoplane in form, was let into the turf at the +point where he landed. + +The second Channel crossing was not made until 1910, a year of +new records. The altitude record had been lifted to over 10,000 +feet, the duration record to 8 hours 12 minutes, and the +distance for a single flight to 365 miles, while a speed of over +65 miles an hour had been achieved, when Jacques de Lesseps, son +of the famous engineer of Suez Canal and Panama fame, crossed +from France to England on a Bleriot monoplane. By this time +flying had dropped so far from the marvellous that this second +conquest of the Channel aroused but slight public interest in +comparison with Bleriot's feat. + +The total weight of Bleriot's machine in Cross Channel trim was +660 lbs., including the pilot and sufficient petrol for a three +hours' run; at a speed of 37 miles an hour, it was capable of +carrying about 5 lbs. per square foot of lifting surface. It +was the three-cylinder 25 horse-power Anzani motor which drove +the machine for the flight. Shortly after the flight had been +accomplished, it was announced that the Bleriot firm would +construct similar machines for sale at L400 apiece--a good +commentary on the prices of those days. + +On June the 2nd, 1910, the third Channel crossing was made by C. +S. Rolls, who flew from Dover, got himself officially observed +over French soil at Barraques, and then flew back without +landing. He was the first to cross from the British side of the +Channel and also was the first aviator who made the double +journey. By that time, however, distance flights had so far +increased as to reduce the value of the feat, and thenceforth +the Channel crossing was no exceptional matter. The honour, +second only to that of the Wright Brothers, remains with Bleriot. + + + +XVI. LONDON TO MANCHESTER + +The last of the great contests to arouse public enthusiasm was +the London to Manchester Flight of 1910. As far back as 1906, +the Daily Mail had offered a prize of L10,000 to the first +aviator who should accomplish this journey, and, for a long time, +the offer was regarded as a perfectly safe one for any person or +paper to make--it brought forth far more ridicule than belief. +Punch offered a similar sum to the first man who should swim the +Atlantic and also for the first flight to Mars and back within a +week, but in the spring of 1910 Claude Grahame White and Paulhan, +the famous French pilot, entered for the 183 mile run on which +the prize depended. Both these competitors flew the Farman +biplane with the 50 horse-power Gnome motor as propulsive power. +Grahame White surveyed the ground along the route, and the L. & +N. W. Railway Company, at his request, whitewashed the sleepers +for 100 yards on the north side of all junctions to give him his +direction on the course. The machine was run out on to the +starting ground at Park Royal and set going at 5.19 a.m. on April +23rd. After a run of 100 yards, the machine went up over +Wormwood Scrubs on its journey to Normandy, near Hillmorten, +which was the first arranged stopping place en route; Grahame +White landed here in good trim at 7.20 a.m., having covered 75 +miles and made a world's record cross country flight. At 8.15 he +set off again to come down at Whittington, four miles short of +Lichfield, at about 9.20, with his machine in good order except +for a cracked landing skid. Twice, on this second stage of the +journey, he had been caught by gusts of wind which turned the +machine fully round toward London, and, when over a wood near +Tamworth, the engine stopped through a defect in the balance +springs of two exhaust valves; although it started up again +after a 100 foot glide, it did not give enough power to give him +safety in the gale he was facing. The rising wind kept him on +the ground throughout the day, and, though he hoped for better +weather, the gale kept up until the Sunday evening. The men in +charge of the machine during its halt had attempted to hold the +machine down instead of anchoring it with stakes and ropes, and, +in consequence of this, the wind blew the machine over on its +back, breaking the upper planes and the tail. Grahame White had +to return to London, while the damaged machine was prepared for +a second flight. The conditions of the competition enacted that +the full journey should be completed within 24 hours, which made +return to the starting ground inevitable. + +Louis Paulhan, who had just arrived with his Farman machine, +immediately got it unpacked and put together in order to be +ready to make his attempt for the prize as soon as the weather +conditions should admit. At 5.31 p.m., on April 27th, he went +up from Hendon and had travelled 50 miles when Grahame White, +informed of his rival's start, set out to overtake him. Before +nightfall Paulhan landed at Lichfield, 117 miles from London, +while Grahame White had to come down at Roden, only 60 miles out. +The English aviator's chance was not so small as it seemed, for, +as Latham had found in his cross-Channel attempts, engine failure +was more the rule than the exception, and a very little thing +might reverse the relative positions. + +A special train accompanied Paulhan along the North-Western +route, conveying Madame Paulhan, Henry Farman, and the mechanics +who fitted the Farman biplane together. Paulhan himself, who +had flown at a height of 1,000 feet, spent the night at +Lichfield, starting again at 4.9 a.m. On the 28th, passing +Stafford at 4.45, Crewe at 5.20, and landing at Burnage, near +Didsbury, at 5.32, having had a clean run. + +Meanwhile, Grahame White had made a most heroic attempt to beat +his rival. An hour before dawn on the 28th, he went to the +small field in which his machine had landed, and in the darkness +managed to make an ascent from ground which made starting +difficult even in daylight. Purely by instinct and his +recollection of the aspect of things the night before, he had to +clear telegraph wires and a railway bridge, neither of which he +could possibly see at that hour. His engine, too, was +faltering, and it was obvious to those who witnessed his start +that its note was far from perfect. + +At 3.50 he was over Nuneaton and making good progress; between +Atherstone and Lichfield the wind caught him and the engine +failed more and more, until at 4.13 in the morning he was forced +to come to earth, having covered 6 miles less distance than in +his first attempt. It was purely a case of engine failure, for, +with full power, he would have passed over Paulhan just as the +latter was preparing for the restart. Taking into consideration +the two machines, there is little doubt that Grahame White +showed the greater flying skill, although he lost the prize. +After landing and hearing of Paulhan's victory, on which he +wired congratulations, he made up his mind to fly to Manchester +within the 24 hours. He started at 5 o'clock in the afternoon +from Polesworth, his landing place, but was forced to land at +5.30 at Whittington, where he had landed on the previous +Saturday. The wind, which had forced his descent, fell again +and permitted of starting once more; on this third stage he +reached Lichfield, only to make his final landing at 7.15 p.m., +near the Trent Valley station. The defective running of the +Gnome engine prevented his completing the course, and his Farman +machine had to be brought back to London by rail. + +The presentation of the prize to Paulhan was made the occasion +for the announcement of a further competition, consisting of a +1,000 mile flight round a part of Great Britain. In this, +nineteen competitors started, and only four finished; the end of +the race was a great fight between Beaumont and Vedrines, both +of whom scorned weather conditions in their determination to +win. Beaumont made the distance in a flying time of 22 hours 28 +minutes 19 seconds, and Vedrines covered the journey in a little +over 23 1/2 hours. Valentine came third on a Deperdussin +monoplane and S. F. Cody on his Cathedral biplane was fourth. +This was in 1911, and by that time heavier-than-air flight had +so far advanced that some pilots had had war experience in the +Italian campaign in Tripoli, while long cross-country flights +were an everyday event, and bad weather no longer counted. + + + +XVII. A SUMMARY, TO 1911 + +There is so much overlapping in the crowded story of the first +years of successful power-driven flight that at this point it is +advisable to make a concise chronological survey of the chief +events of the period of early development, although much of this +is of necessity recapitulation. The story begins, of course, +with Orville Wright's first flight of 852 feet at Kitty Hawk on +December 19th, 1903. The next event of note was Wright's flight +of 11.12 miles in 18 minutes 9 seconds at Dayton, Ohio, on +September 26th, 1905, this being the first officially recorded +flight. On October 4th of the same year, Wright flew 20.75 miles +in 33 minutes 17 seconds, this being the first flight of over 20 +miles ever made. Then on September 14th 1906, Alberto +Santos-Dumont made a flight of eight seconds on the second +heavier-than-air machine he had constructed. It was a big +box-kite-like machine; this was the second power-driven aeroplane +in Europe to fly, for although Santos-Dumont's first machine +produced in 1905 was reckoned an unsuccessful design, it had +actually got off the ground for brief periods. Louis Bleriot +came into the ring on April 5th, 1907, with a first flight of 6 +seconds on a Bleriot monoplane, his eighth but first successful +construction. + +Henry Farman made his first appearance in the history of aviation +with a flight of 935 feet on a Voisin biplane on October 15th +1907. On October 25th, in a flight of 2,530 feet, he made the +first recorded turn in the air, and on March 29th, 1908, carrying +Leon Delagrange on a Voisin biplane, he made the first passenger +flight. On April 10th of this year, Delagrange, in flying 1 1/2 +miles, made the first flight in Europe exceeding a mile in +distance. He improved on this by flying 10 1/2 miles at Milan on +June 22nd, while on July 8th, at Turin, he took up Madame +Peltier, the first woman to make an aeroplane flight. + +Wilbur Wright, coming over to Europe, made his first appearance +on the Continent with a flight of 1 3/4 minutes at Hunaudieres, +France, on August 8th, 1908. On September 6th, at Chalons, he +flew for 1 hour 4 minutes 26 seconds with a passenger, this +being the first flight in which an hour in the air was exceeded +with a passenger on board. + +on September 12th 1908, Orville Wright, flying at Fort Meyer, +U.S.A., with Lieut. Selfridge as passenger, crashed his +machine, suffering severe injuries, while Selfridge was killed. +This was the first aeroplane fatality. On October 30th, 1908, +Farman made the first cross-country flight, covering the +distance of 17 miles between Bouy and Rheims. The next day, +Louis Bleriot, in flying from Toury to Artenay, made two +landings en route, this being the first cross-country flight +with landings. On the last day of the year, Wilbur Wright won +the Michelin Cup at Auvours with a flight of 90 miles, which, +lasting 2 hours 20 minutes 23 seconds, exceeded 2 hours in the +air for the first time. + +On January 2nd, 1909, S. F. Cody opened the New Year by making +the first observed flight at Farnborough on a British Army +aeroplane. It was not until July 18th of 1909 that the first +European height record deserving of mention was put up by +Paulhan, who achieved a height of 450 feet on a Voisin +biplane. This preceded Latham's first attempt to fly the +Channel by two days, and five days later, on the 25th of the +month, Bleriot made the first Channel crossing. The Rheims +Meeting followed on August 22nd, and it was a great day for +aviation when nine machines were seen in the air at once. It +was here that Farman, with a 118 mile flight, first exceeded +the hundred miles, and Latham raised the height record +officially to 500 feet, though actually he claimed to have +reached 1,200 feet. On September 8th, Cody, flying from +Aldershot, made a 40 mile journey, setting up a new +cross-country record. On October 19th the Comte de Lambert +flew from Juvisy to Paris, rounded the Eiffel Tower and flew +back. J. T. C. Moore-Brabazon made the first circular mile +flight by a British aviator on an all-British machine in Great +Britain, on October 30th, flying a Short biplane with a Green +engine. Paulhan, flying at Brooklands on November 2nd, +accomplished 96 miles in 2 hours 48 minutes, creating a British +distance record; on the following day, Henry Farman made a +flight of 150 miles in 4 hours 22 minutes at Mourmelon, and on +the 5th of the month, Paulhan, flying a Farman biplane, made a +world's height record of 977 feet. This, however, was not to +stand long, for Latham got up to 1,560 feet on an Antoinette at +Mourmelon on December 1st. December 31st witnessed the first +flight in Ireland, made by H. Ferguson on a monoplane which he +himself had constructed at Downshire Park, Lisburn. + +These, thus briefly summarised, are the principal events up to +the end of 1909. 1910 opened with tragedy, for on January 4th +Leon Delagrange, one of the greatest pilots of his time, was +killed while flying at Pau. The machine was the Bleriot XI which +Delagrange had used at the Doncaster meeting, and to which +Delagrange had fitted a 50 horse-power Gnome engine, increasing +the speed of the machine from its original 30 to 45 miles per +hour. With the Rotary Gnome engine there was of necessity a +certain gyroscopic effect, the strain of which proved too much +for the machine. Delagrange had come to assist in the +inauguration of the Croix d'Hins aerodrome, and had twice lapped +the course at a height of about 60 feet. At the beginning of +the third lap, the strain of the Gnome engine became too great +for the machine; one wing collapsed as if the stay wires had +broken, and the whole machine turned over and fell, killing +Delagrange. + +On January 7th Latham, flying at Mourmelon, first made the +vertical kilometre and dedicated the record to Delagrange, this +being the day of his friend's funeral. The record was +thoroughly authenticated by a large registering barometer which +Latham carried, certified by the officials of the French Aero +Club. Three days later Paulhan, who was at Los Angeles, +California, raised the height record to 4,146 feet. + +On January 25th the Brussels Exhibition opened, when the +Antoinette monoplane, the Gaffaux and Hanriot monoplanes, +together with the d'Hespel aeroplane, were shown; there were +also the dirigible Belgica and a number of interesting aero +engines, including a German airship engine and a four-cylinder +50 horse-power Miesse, this last air-cooled by means of 22 +fans driving a current of air through air jackets surrounding +fluted cylinders. + +On April 2nd Hubert Le Blon, flying a Bleriot with an Anzani +engine, was killed while flying over the water. His machine was +flying quite steadily, when it suddenly heeled over and came +down sideways into the sea; the motor continued running for some +seconds and the whole machine was drawn under water. When boats +reached the spot, Le Blon was found lying back in the driving +seat floating just below the surface. He had done good flying +at Doncaster, and at Heliopolis had broken the world's speed +records for 5 and 10 kilometres. The accident was attributed +to fracture of one of the wing stay wires when running into a +gust of wind. + +The next notable event was Paulhan's London-Manchester flight, +of which full details have already been given. In May Captain +Bertram Dickson, flying at the Tours meeting, beat all the +Continental fliers whom he encountered, including Chavez, the +Peruvian, who later made the first crossing of the Alps. +Dickson was the first British winner of international aviation +prizes. + +C. S. Rolls, of whom full details have already been given, was +killed at Bournemouth on July 12th, being the first British +aviator of note to be killed in an aeroplane accident. His +return trip across the Channel had taken place on June 2nd. +Chavez, who was rapidly leaping into fame, as a pilot, raised +the British height record to 5,750 feet while flying at +Blackpool on August 3rd. On the 11th of that month, Armstrong +Drexel, flying a Bleriot, made a world's height record of 6,745 +feet. + +It was in 1910 that the British War office first began fully to +realise that there might be military possibilities in +heavier-than-air flying. C. S. Rolls had placed a Wright +biplane at the disposal of the military authorities, and Cody, +as already recorded, had been experimenting with a biplane type +of his own for some long period. Such development as was +achieved was mainly due to the enterprise and energy of Colonel +J. E. Capper, C.B., appointed to the superintendency of the +Balloon Factory and Balloon School at Farnborough in 1906. +Colonel Capper's retirement in 1910 brought (then) Mr Mervyn +O'Gorman to command, and by that time the series of successes of +the Cody biplane, together with the proved efficiency of the +aeroplane in various civilian meetings, had convinced the +British military authorities that the mastery of the air did not +lie altogether with dirigible airships, and it may be said that +in 1910 the British War office first began seriously to consider +the possibilities of the aeroplane, though two years more were +to elapse before the formation of the Royal Flying Corps marked +full realisation of its value. + +A triumph and a tragedy were combined in September of 1910. On +the 23rd of the month, Georges Chavez set out to fly across the +Alps on a Bleriot monoplane. Prizes had been offered by the +Milan Aviation Committee for a flight from Brigue in Switzerland +over the Simplon Pass to Milan, a distance of 94 miles with a +minimum height of 6,600 feet above sea level. Chavez started at +1.30 p.m. On the 23rd, and 41 minutes later he reached +Domodossola, 25 miles distant. Here he descended, numbed with +the cold of the journey; it was said that the wings of his +machine collapsed when about 30 feet from the ground, but +however this may have been, he smashed the machine on landing, +and broke both legs, in addition to sustaining other serious +injuries. He lay in hospital until the 27th September, when he +died, having given his life to the conquest of the Alps. His +death in the moment of success was as great a tragedy as were +those of Pilcher and Lilienthal. + +The day after Chavez's death, Maurice Tabuteau flew across the +Pyrenees, landing in the square at Biarritz. On December 30th, +Tabuteau made a flight of 365 miles in 7 hours 48 minutes. +Farman, on December 18th, had flown for over 8 hours, but his +total distance was only 282 miles. The autumn of this year was +also noteworthy for the fact that aeroplanes were first +successfully used in the French Military Manoeuvres. The +British War Office, by the end of the year, had bought two +machines, a military type Farman and a Paulhan, ignoring British +experimenters and aeroplane builders of proved reliability. +These machines, added to an old Bleriot two-seater, appear to +have constituted the British aeroplane fleet of the period. + +There were by this time three main centres of aviation in +England, apart from Cody, alone on Laffan's Plain. These three +were Brooklands, Hendon, and the Isle of Sheppey, and of the +three Brooklands was chief. Here such men as Graham Gilmour, +Rippen, Leake, Wickham, and Thomas persistently experimented. +Hendon had its own little group, and Shellbeach, Isle of +Sheppey, held such giants of those days as C. S. Rolls and +Moore Brabazon, together with Cecil Grace and Rawlinson. One or +other, and sometimes all of these were deserted on the occasion +of some meeting or other, but they were the points where the +spade work was done, Brooklands taking chief place. 'If you want +the early history of flying in England, it is there,' one of the +early school remarked, pointing over toward Brooklands course. + +1911 inaugurated a new series of records of varying character. +On the 17th January, E. B. Ely, an American, flew from the shore +of San Francisco to the U.S. cruiser Pennsylvania, landing on the +cruiser, and then flew back to the shore. The British military +designing of aeroplanes had been taken up at Farnborough by G. H. +de Havilland, who by the end of January was flying a machine of +his own design, when he narrowly escaped becoming a casualty +through collision with an obstacle on the ground, which swept the +undercarriage from his machine. + +A list of certified pilots of the countries of the world was +issued early in 1911, showing certificates granted up to the +end of 1910. France led the way easily with 353 pilots; England +came next with 57, and Germany next with 46; Italy owned 32, +Belgium 27, America 26, and Austria 19; Holland and Switzerland +had 6 aviators apiece, while Denmark followed with 3, Spain with +2, and Sweden with 1. The first certificate in England was that +of J. T. C. Moore-Brabazon, while Louis Bleriot was first on +the French list and Glenn Curtiss, first holder of an American +certificate, also held the second French brevet. + +On the 7th March, Eugene Renaux won the Michelin Grand Prize by +flying from the French Aero Club ground at St Cloud and landing +on the Puy de Dome. The landing, which was one of the +conditions of the prize, was one of the most dangerous +conditions ever attached to a competition; it involved dropping +on to a little plateau 150 yards square, with a possibility of +either smashing the machine against the face of the mountain, or +diving over the edge of the plateau into the gulf beneath. The +length of the journey was slightly over 200 miles and the height +of the landing point 1,465 metres, or roughly 4,500 feet above +sea-level. Renaux carried a passenger, Doctor Senoucque, a +member of Charcot's South Polar Expedition. + +The 1911 Aero Exhibition held at Olympia bore witness to the +enormous strides made in construction, more especially by +British designers, between 1908 and the opening of the Show. +The Bristol Firm showed three machines, including a military +biplane, and the first British built biplane with tractor screw. +The Cody biplane, with its enormous size rendering it a +prominent feature of the show, was exhibited. Its designer +anticipated later engines by expressing his desire for a motor +of 150 horse-power, which in his opinion was necessary to get +the best results from the machine. The then famous Dunne +monoplane was exhibited at this show, its planes being V-shaped +in plan, with apex leading. It embodied the results of very +lengthy experiments carried out both with gliders and +power-driven machines by Colonel Capper, Lieut. Gibbs, and +Lieut. Dunne, and constituted the longest step so far taken in +the direction of inherent stability. + +Such forerunners of the notable planes of the war period as the +Martin Handasyde, the Nieuport, Sopwith, Bristol, and Farman +machines, were features of the show; the Handley-Page monoplane, +with a span of 32 feet over all, a length of 22 feet, and a +weight of 422 lbs., bore no relation at all to the twin-engined +giant which later made this firm famous. In the matter of +engines, the principal survivals to the present day, of which +this show held specimens, were the Gnome, Green, Renault +air-cooled, Mercedes four-cylinder dirigible engine of 115 +horse-power, and 120 horsepower Wolseley of eight cylinders for +use with dirigibles. + +On April 12th, of 1911, Paprier, instructor at the Bleriot +school at Hendon, made the first non-stop flight between London +and Paris. He left the aerodrome at 1.37 p.m., and arrived at +Issy-les-Moulineaux at 5.33 p.m., thus travelling 250 miles in a +little under 4 hours. He followed the railway route practically +throughout, crossing from Dover to nearly opposite Calais, +keeping along the coast to Boulogne, and then following the Nord +Railway to Amiens, Beauvais, and finally Paris. + +In May, the Paris-Madrid race took place; Vedrines, flying a +Morane biplane, carried off the prize by first completing the +distance of 732 miles. The Paris-Rome race of 916 miles was won +in the same month by Beaumont, flying a Bleriot monoplane. In +July, Koenig won the German National Circuit race of 1,168 miles +on an Albatross biplane. This was practically simultaneous with +the Circuit of Britain won by Beaumont, who covered 1,010 miles +on a Bleriot monoplane, having already won the +Paris-Brussels-London-Paris Circuit of 1,080 miles, this also on +a Bleriot. It was in August that a new world's height record of +11,152 feet was set up by Captain Felix at Etampes, while +on the 7th of the month Renaux flew nearly 600 miles on a +Maurice Farman machine in 12 hours. Cody and Valentine were +keeping interest alive in the Circuit of Britain race, although +this had long been won, by determinedly plodding on at finishing +the course. + +On September 9th, the first aerial post was tried between Hendon +and Windsor, as an experiment in sending mails by aeroplane. +Gustave Hamel flew from Hendon to Windsor and back in a strong +wind. A few days later, Hamel went on strike, refusing to carry +further mails unless the promoters of the Aerial Postal Service +agreed to pay compensation to Hubert, who fractured both his legs +on the 11th of the month while engaged in aero postal work. The +strike ended on September 25th, when Hamel resumed mail-carrying +in consequence of the capitulation of the Postmaster-General, who +agreed to set aside L500 as compensation to Hubert. + +September also witnessed the completion in America of a flight +across the Continent, a distance of 2,600 miles. The only +competitor who completed the full distance was C. P. Rogers, +who was disqualified through failing to comply with the time +limit. Rogers needed so many replacements to his machine on the +journey that, expressing it in American fashion, he arrived with +practically a dfferent aeroplane from that with which he +started. + +With regard to the aerial postal service, analysis of the matter +carried and the cost of the service seemed to show that with a +special charge of one shilling for letters and sixpence for post +cards, the revenue just balanced the expenditure. It was not +possible to keep to the time-table as, although the trials were +made in the most favourable season of the year, aviation was not +sufficiently advanced to admit of facing all weathers and +complying with time-table regulations. + +French military aeroplane trials took place at Rheims in +October, the noteworthy machines being Antoinette, Farman, +Nieuport, and Deperdussin. The tests showed the Nieuport +monoplane with Gnome motor as first in position; the Breguet +biplane was second, and the Deperdussin monoplanes third. The +first five machines in order of merit were all engined with the +Gnome motor. + +The records quoted for 1911 form the best evidence that can +be given of advance in design and performance during the year. +It will be seen that the days of the giants were over; design +was becoming more and more standardised and aviation not so much +a matter of individual courage and even daring, as of the +reliability of the machine and its engine. This was the first +year in which the twin-engined aeroplane made its appearance, +and it was the year, too, in which flying may be said to have +grown so common that the 'meetings' which began with Rheims were +hardly worth holding, owing to the fact that increase in height +and distance flown rendered it no longer necessary for a +would-be spectator of a flight to pay half a crown and enter an +enclosure. Henceforth, flying as a spectacle was very little to +be considered; its commercial aspects were talked of, and to a +very slight degree exploited, but, more and more, the fact that +the aeroplane was primarily an engine of war, and the growing +German menace against the peace of the world combined to point +the way of speediest development, and the arrangements for the +British Military Trials to be held in August, 1912, showed that +even the British War office was waking up to the potentialities +of this new engine of war. + + + +XVIII. A SUMMARY, TO 1914 + +Consideration of the events in the years immediately preceding +the War must be limited to as brief a summary as possible, this +not only because the full history of flying achievements is +beyond the compass of any single book, but also because, viewing +the matter in perspective, the years 1903-1911 show up as far +more important as regards both design and performance. From +1912 to August of 1914, the development of aeronautics was +hindered by the fact that it had not progressed far enough to +form a real commercial asset in any country. The meetings which +drew vast concourses of people to such places as Rheims and +Bournemouth may have been financial successes at first, but, as +flying grew more common and distances and heights extended, a +great many people found it other than worth while to pay for +admission to an aerodrome. The business of taking up passengers +for pleasure flights was not financially successful, and, +although schemes for commercial routes were talked of, the +aeroplane was not sufficiently advanced to warrant the +investment of hard cash in any of these projects. There was a +deadlock; further development was necessary in order to secure +financial aid, and at the same time financial aid was necessary +in order to secure further development. Consequently, neither +was forthcoming. + +This is viewing the matter in a broad and general sense; there +were firms, especially in France, but also in England and +America, which looked confidently for the great days of flying to +arrive, and regarded their sunk capital as investment which would +eventually bring its due return. But when one looks back on +those years, the firms in question stand out as exceptions to the +general run of people, who regarded aeronautics as something +extremely scientific, exceedingly dangerous, and very expensive. +The very fame that was attained by such pilots as became +casualties conduced to the advertisement of every death, and the +dangers attendant on the use of heavier-than-air machines became +greatly exaggerated; considering the matter as one of number of +miles flown, even in the early days, flying exacted no more toll +in human life than did railways or road motors in the early +stages of their development. But to take one instance, when C. +S. Rolls was killed at Bournemouth by reason of a faulty +tail-plane, the fact was shouted to the whole world with almost +as much vehemence as characterised the announcement of the +Titanic sinking in mid-Atlantic. + +Even in 1911 the deadlock was apparent; meetings were falling +off in attendance, and consequently in financial benefit to the +promoters; there remained, however, the knowledge--for it was +proved past question--that the aeroplane in its then stage of +development was a necessity to every army of the world. France +had shown this by the more than interest taken by the French +Government in what had developed into an Air Section of the +French army; Germany, of course, was hypnotised by Count +Zeppelin and his dirigibles, to say nothing of the Parsevals +which had been proved useful military accessories; in spite of +this, it was realised in Germany that the aeroplane also had its +place in military affairs. England came into the field with the +military aeroplane trials of August 1st to 15th, 1912, barely two +months after the founding of the Royal Flying Corps. + +When the R.F.C. was founded--and in fact up to two years after +its founding--in no country were the full military +potentialities of the aeroplane realised; it was regarded as an +accessory to cavalry for scouting more than as an independent +arm; the possibilities of bombing were very vaguely considered, +and the fact that it might be possible to shoot from an +aeroplane was hardly considered at all. The conditions of the +British Military Trials of 1912 gave to the War office the +option of purchasing for L1,000 any machine that might be +awarded a prize. Machines were required, among other things, to +carry a useful load of 350 lbs. in addition to equipment, with +fuel and oil for 4 1/2-hours; thus loaded, they were required to +fly for 3 hours, attaining an altitude of 4,500 feet, maintaining +a height of 1,500 feet for 1 hour, and climbing 1,000 feet from +the ground at a rate of 200 feet per minute, 'although 300 feet +per minute is desirable.' They had to attain a speed of not less +than 55 miles per hour in a calm, and be able to plane down to +the ground in a calm from not more than 1,000 feet with engine +stopped, traversing 6,000 feet horizontal distance. For those +days, the landing demands were rather exacting; the machine +should be able to rise without damage from long grass, clover, or +harrowed land, in 100 yards in a calm, and should be able to land +without damage on any cultivated ground, including rough ploughed +land, and, when landing on smooth turf in a calm, be able to pull +up within 75 yards of the point of first touching the ground. It +was required that pilot and observer should have as open a view +as possible to front and flanks, and they should be so shielded +from the wind as to be able to communicate with each other. +These are the main provisions out of the set of conditions laid +down for competitors, but a considerable amount of leniency was +shown by the authorities in the competition, who obviously wished +to try out every machine entered and see what were its +capabilities. + +The beginning of the competition consisted in assembling the +machines against time from road trim to flying trim. Cody's +machine, which was the only one to be delivered by air, took 1 +hour and 35 minutes to assemble; the best assembling time was +that of the Avro, which was got into flying trim in 14 minutes 30 +seconds. This machine came to grief with Lieut. Parke as pilot, +on the 7th, through landing at very high speed on very bad +ground; a securing wire of the under-carriage broke in the +landing, throwing the machine forward on to its nose and then +over on its back. Parke was uninjured, fortunately; the damaged +machine was sent off to Manchester for repair and was back again +on the 16th of August. + +It is to be noted that by this time the Royal Aircraft Factory +was building aeroplanes of the B.E. and F.E. types, but at the +same time it is also to be noted that British military interest +in engines was not sufficient to bring them up to the high level +attained by the planes, and it is notorious that even the +outbreak of war found England incapable of providing a really +satisfactory aero engine. In the 1912 Trials, the only machines +which actually completed all their tests were the Cody biplane, +the French Deperdussin, the Hanriot, two Bleriots and a Maurice +Farman. The first prize of L4,000, open to all the world, went +to F. S. Cody's British-built biplane, which complied with all +the conditions of the competition and well earned its official +acknowledgment of supremacy. The machine climbed at 280 feet per +minute and reached a height of 5,000 feet, while in the landing +test, in spite of its great weight and bulk, it pulled up on +grass in 56 yards. The total weight was 2,690 lbs. when fully +loaded, and the total area of supporting surface was 500 square +feet; the motive power was supplied by a six-cylinder 120 +horsepower Austro-Daimler engine. The second prize was taken by +A. Deperdussin for the French-built Deperdussin monoplane. Cody +carried off the only prize awarded for a British-built plane, +this being the sum of L1,000, and consolation prizes of L500 each +were awarded to the British Deperdussin Company and The British +and Colonial Aeroplane Company, this latter soon to become famous +as makers of the Bristol aeroplane, of which the war honours are +still fresh in men's minds. + +While these trials were in progress Audemars accomplished the +first flight between Paris and Berlin, setting out from Issy +early in the morning of August 18th, landing at Rheims to refill +his tanks within an hour and a half, and then coming into bad +weather which forced him to land successively at Mezieres, +Laroche, Bochum, and finally nearly Gersenkirchen, where, owing +to a leaky petrol tank, the attempt to win the prize offered for +the first flight between the two capitals had to be abandoned +after 300 miles had been covered, as the time limit was +definitely exceeded. Audemars determined to get through to +Berlin, and set off at 5 in the morning of the 19th, only to be +brought down by fog; starting off again at 9.15 he landed at +Hanover, was off again at 1.35, and reached the Johannisthal +aerodrome in the suburbs of Berlin at 6.48 that evening. + +As early as 1910 the British Government possessed some ten +aeroplanes, and in 1911 the force developed into the Army Air +Battalion, with the aeroplanes under the control of Major J. H. +Fulton, R.F.A. Toward the end of 1911 the Air Battalion was +handed over to (then) Brig.-Gen. D. Henderson, Director of +Military Training. On June 6th, 1912, the Royal Flying Corps was +established with a military wing under Major F. H. Sykes and a +naval wing under Commander C. R. Samson. A joint Naval and +Military Flying School was established at Upavon with Captain +Godfrey M. Paine, R.N., as Commandant and Major Hugh Trenchard +as Assistant Commandant. The Royal Aircraft Factory brought out +the B.E. and F.E. types of biplane, admittedly superior to any +other British design of the period, and an Aircraft Inspection +Department was formed under Major J. H. Fulton. The military +wing of the R.F.C. was equipped almost entirely with machines +of Royal Aircraft Factory design, but the Navy preferred to +develop British private enterprise by buying machines from +private firms. On July 1st, 1914 the establishment of the Royal +Naval Air Service marked the definite separation of the military +and naval sides of British aviation, but the Central Flying +School at Upavon continued to train pilots for both services. + +It is difficult at this length of time, so far as the military +wing was concerned, to do full justice to the spade work done by +Major-General Sir David Henderson in the early days. Just before +war broke out, British military air strength consisted officially +of eight squadrons, each of 12 machines and 13 in reserve, with +the necessary complement of road transport. As a matter of fact, +there were three complete squadrons and a part of a fourth which +constituted the force sent to France at the outbreak of war. The +value of General Henderson's work lies in the fact that, in spite +of official stinginess and meagre supplies of every kind, he +built up a skeleton organisation so elastic and so well thought +out that it conformed to war requirements as well as even the +German plans fitted in with their aerial needs. On the 4th of +August, 1914, the nominal British air strength of the military +wing was 179 machines. Of these, 82 machines proceeded to +France, landing at Amiens and flying to Maubeuge to play their +part in the great retreat with the British Expeditionary Force, +in which they suffered heavy casualties both in personnel and +machines. The history of their exploits, however, belongs to the +War period. + +The development of the aeroplane between 1912 and 1914 can be +judged by comparison of the requirements of the British War +Office in 1912 with those laid down in an official memorandum +issued by the War Office in February, 1914. This latter +called for a light scout aeroplane, a single-seater, with fuel +capacity to admit of 300 miles range and a speed range of from +50 to 85 miles per hour. It had to be able to climb 3,500 feet +in five minutes, and the engine had to be so constructed that +the pilot could start it without assistance. At the same time, +a heavier type of machine for reconnaissance work was called +for, carrying fuel for a 200 mile flight with a speed range of +between 35 and 60 miles per hour, carrying both pilot and +observer. It was to be equipped with a wireless telegraphy set, +and be capable of landing over a 30 foot vertical obstacle and +coming to rest within a hundred yards' distance from the +obstacle in a wind of not more than 15 miles per hour. A third +requirement was a heavy type of fighting aeroplane accommodating +pilot and gunner with machine gun and ammunition, having a speed +range of between 45 and 75 miles per hour and capable of +climbing 3,500 feet in 8 minutes. It was required to carry fuel +for a 300 mile flight and to give the gunner a clear field of +fire in every direction up to 30 degrees on each side of the +line of flight. Comparison of these specifications with those +of the 1912 trials will show that although fighting, scouting, +and reconnaissance types had been defined, the development of +performance compared with the marvellous development of the +earlier years of achieved flight was small. + +Yet the records of those years show that here and there an +outstanding design was capable of great things. On the 9th +September, 1912, Vedrines, flying a Deperdussin monoplane at +Chicago, attained a speed of 105 miles an hour. On August 12th, +G. de Havilland took a passenger to a height of 10,560 feet +over Salisbury Plain, flying a B.E. biplane with a 70 +horse-power Renault engine. The work of de Havilland may be +said to have been the principal influence in British military +aeroplane design, and there is no doubt that his genius was in +great measure responsible for the excellence of the early B.E. +and F.E. types. + +on the 31st May, 1913, H. G. Hawker, flying at Brooklands, +reached a height of 11,450 feet on a Sopwith biplane engined with +an 80 horse-power Gnome engine. On June 16th, with the same type +of machine and engine, he achieved 12,900 feet. On the 2nd +October, in the same year, a Grahame White biplane with 120 +horse-power Austro-Daimler engine, piloted by Louis Noel, made a +flight of just under 20 minutes carrying 9 passengers. In France +a Nieuport monoplane piloted by G. Legagneaux attained a height +of 6,120 metres, or just over 20,070 feet, this being the world's +height record. It is worthy of note that of the world's aviation +records as passed by the International Aeronautical Federation up +to June 30th, 1914, only one, that of Noel, is credited to Great +Britain. + +Just as records were made abroad, with one exception, so were +the really efficient engines. In England there was the Green +engine, but the outbreak of war found the Royal Flying Corps +with 80 horse-power Gnomes, 70 horse-power Renaults, and one or +two Antoinette motors, but not one British, while the Royal +Naval Air Service had got 20 machines with engines of similar +origin, mainly land planes in which the wheeled undercarriages +had been replaced by floats. France led in development, and +there is no doubt that at the outbreak of war, the French +military aeroplane service was the best in the world. It was +mainly composed of Maurice Farman two-seater biplanes and +Bleriot monoplanes-- the latter type banned for a period on +account of a number of serious accidents that took place in 1912 + +America had its Army Aviation School, and employed Burgess-Wright +and Curtiss machines for the most part. In the pre-war years, +once the Wright Brothers had accomplished their task, America's +chief accomplishment consisted in the development of the 'Flying + +Boat,' alternatively named with characteristic American +clumsiness, 'The Hydro-Aeroplane.' In February of 1911, Glenn +Curtiss attached a float to a machine similar to that with which +he won the first Gordon-Bennett Air Contest and made his first +flying boat experiment. From this beginning he developed the +boat form of body which obviated the use and troubles of +floats--his hydroplane became its own float. + +Mainly owing to greater engine reliability the duration records +steadily increased. By September of 1912 Fourny, on a Maurice +Farman biplane, was able to accomplish a distance of 628 miles +without a landing, remaining in the air for 13 hours 17 minutes +and just over 57 seconds. By 1914 this was raised by the German +aviator, Landemann, to 21 hours 48 3/4 seconds. The nature of +this last record shows that the factors in such a record had +become mere engine endurance, fuel capacity, and capacity of the +pilot to withstand air conditions for a prolonged period, rather +than any exceptional flying skill. + +Let these years be judged by the records they produced, and even +then they are rather dull. The glory of achievement such as +characterised the work of the Wright Brothers, of Bleriot, and +of the giants of the early days, had passed; the splendid +courage, the patriotism and devotion of the pilots of the War +period had not yet come to being. There was progress, past +question, but it was mechanical, hardly ever inspired. The +study of climatic conditions was definitely begun and +aeronautical meteorology came to being, while another development +already noted was the fitting of wireless telegraphy to +heavier-than-air machines, as instanced in the British War +office specification of February, 1914. These, however, were +inevitable; it remained for the War to force development beyond +the inevitable, producing in five years that which under normal +circumstances might easily have occupied fifty --the aeroplane of +to-day; for, as already remarked, there was a deadlock, and any +survey that may be made of the years 1912-1914, no matter how +superficial, must take it into account with a view to retaining +correct perspective in regard to the development of the +aeroplane. + +There is one story of 1914 that must be included, however +briefly, in any record of aeronautical achievement, since it +demonstrates past question that to Professor Langley really +belongs the honour of having achieved a design which would ensure +actual flight, although the series of accidents which attended +his experiments gave to the Wright Brothers the honour of first +leaving the earth and descending without accident in a +power-driven heavier-than-air machine. In March, 1914, Glenn +Curtiss was invited to send a flying boat to Washington for the +celebration of 'Langley Day,' when he remarked, 'I would like to +put the Langley aeroplane itself in the air.' In consequence of +this remark, Secretary Walcot of the Smithsonian Institution +authorised Curtiss to re-canvas the original Langley aeroplane +and launch it either under its own power or with a more recent +engine and propeller. Curtiss completed this, and had the +machine ready on the shores of Lake Keuka, Hammondsport, N.Y., by +May. The main object of these renewed trials was to show whether +the original Langley machine was capable of sustained free flight +with a pilot, and a secondary object was to determine more fully +the advantages of the tandem monoplane type; thus the aeroplane +was first flown as nearly as possible in its original condition, +and then with such modifications as seemed desirable. The only +difference made for the first trials consisted in fitting floats +with connecting trusses; the steel main frame, wings, rudders, +engine, and propellers were substantially as they had been in +1903. The pilot had the same seat under the main frame and the +same general system of control. He could raise or lower the +craft by moving the rear rudder up and down; he could steer +right or left by moving the vertical rudder. He had no ailerons +nor wing-warping mechanism, but for lateral balance depended on +the dihedral angle of the wings and upon suitable movements of +his weight or of the vertical rudder. + +After the adjustments for actual flight had been made in the +Curtiss factory, according to the minute descriptions contained +in the Langley Memoir on Mechanical Flight, the aeroplane was +taken to the shore of Lake Keuka, beside the Curtiss hangars, +and assembled for launching. On a clear morning (May 28th) and +in a mild breeze, the craft was lifted on to the water by a +dozen men and set going, with Mr Curtiss at the steering wheel, +esconced in the little boat-shaped car under the forward part of +the frame. The four-winged craft, pointed somewhat across the +wind, went skimming over the waveless, then automatically headed +into the wind, rose in level poise, soared gracefully for 150 +feet, and landed softly on the water near the shore. Mr Curtiss +asserted that he could have flown farther, but, being unused to +the machine, imagined that the left wings had more resistance +than the right. The truth is that the aeroplane was perfectly +balanced in wing resistance, but turned on the water like a +weather vane, owing to the lateral pressure on its big rear +rudder. Hence in future experiments this rudder was made +turnable about a vertical axis, as well as about the horizontal +axis used by Langley. Henceforth the little vertical rudder +under the frame was kept fixed and inactive.[*] + +That the Langley aeroplane was subsequently fitted with an 80 +horse-power Curtiss engine and successfully flown is of little +interest in such a record as this, except for the fact that with +the weight nearly doubled by the new engine and accessories the +machine flew successfully, and demonstrated the perfection of +Langley's design by standing the strain. The point that is of +most importance is that the design itself proved a success and +fully vindicated Langley's work. At the same time, it would be +unjust to pass by the fact of the flight without according to +Curtiss due recognition of the way in which he paid tribute to +the genius of the pioneer by these experiments. + +[*] Smithsonian Publications No. 2329. + + + +XIX. THE WAR PERIOD--I + +Full record of aeronautical progress and of the accomplishments +of pilots in the years of the War would demand not merely a +volume, but a complete library, and even then it would be barely +possible to pay full tribute to the heroism of pilots of the war +period. There are names connected with that period of which the +glory will not fade, names such as Bishop, Guynemer, Boelcke, +Ball, Fonck, Immelmann, and many others that spring to mind as +one recalls the 'Aces' of the period. In addition to the +pilots, there is the stupendous development of the +machines--stupendous when the length of the period in which it +was achieved is considered. + +The fact that Germany was best prepared in the matter of +heavier-than-air service machines in spite of the German faith +in the dirigible is one more item of evidence as to who forced +hostilities. The Germans came into the field with well over 600 +aeroplanes, mainly two-seaters of standardised design, and with +factories back in the Fatherland turning out sufficient new +machines to make good the losses. There were a few +single-seater scouts built for speed, and the two-seater +machines were all fitted with cameras and bomb-dropping gear. +Manoeuvres had determined in the German mind what should be the +uses of the air fleet; there was photography of fortifications +and field works; signalling by Very lights; spotting for the +guns, and scouting for news of enemy movements. The methodical +German mind had arranged all this beforehand, but had not allowed +for the fact that opponents might take counter-measures which +would upset the over-perfect mechanism of the air service just as +effectually as the great march on Paris was countered by the +genius of Joffre. + +The French Air Force at the beginning of the War consisted of +upwards of 600 machines. These, unlike the Germans, were not +standardised, but were of many and diverse types. In order to +get replacements quickly enough, the factories had to work on +the designs they had, and thus for a long time after the +outbreak of hostilities standardisation was an impossibility. +The versatility of a Latin race in a measure compensated for +this; from the outset, the Germans tried to overwhelm the French +Air Force, but failed, since they had not the numerical +superiority, nor--this equally a determining factor--the +versatility and resource of the French pilots. They calculated +on a 50 per cent superiority to ensure success; they needed more +nearly 400 per cent, for the German fought to rule, avoiding +risks whenever possible, and definitely instructed to save both +machines and pilots wherever possible. French pilots, on the +other hand, ran all the risks there were, got news of German +movements, bombed the enemy, and rapidly worked up a very +respectable antiaircraft force which, whatever it may have +accomplished in the way of hitting German planes, got on the +German pilots' nerves. + +It has already been detailed how Britain sent over 82 planes as +its contribution to the military aerial force of 1914. These +consisted of Farman, Caudron, and Short biplanes, together with +Bleriot, Deperdussin and Nieuport monoplanes, certain R.A.F. +types, and other machines of which even the name barely survives +--the resourceful Yankee entitles them 'orphans.' It is on +record that the work of providing spares might have been rather +complicated but for the fact that there were none. + +There is no doubt that the Germans had made study of aerial +military needs just as thoroughly as they had perfected their +ground organisation. Thus there were 21 illuminated aircraft +stations in Germany before the War, the most powerful being at +Weimar, where a revolving electric flash of over 27 million +candle-power was located. Practically all German aeroplane +tests in the period immediately preceding the War were of a +military nature, and quite a number of reliability tests were +carried out just on the other side of the French frontier. +Night flying and landing were standardised items in the German +pilot's course of instruction while they were still experimental +in other countries, and a system of signals was arranged which +rendered the instructional course as perfect as might be. + +The Belgian contribution consisted of about twenty machines fit +for active service and another twenty which were more or less +useful as training machines. The material was mainly French, +and the Belgian pilots used it to good account until German +numbers swamped them. France, and to a small extent England, +kept Belgian aviators supplied with machines throughout the War. + +The Italian Air Fleet was small, and consisted of French machines +together with a percentage of planes of Italian origin, of which +the design was very much a copy of French types. It was not +until the War was nearing its end that the military and naval +services relied more on the home product than on imports. This +does not apply to engines, however, for the F.I.A.T. and S.C.A.T. + +were equal to practically any engine of Allied make, both in +design and construction. + +Russia spent vast sums in the provision of machines: the giant +Sikorsky biplane, carrying four 100 horsepower Argus motors, +was designed by a young Russian engineer in the latter part of +1913, and in its early trials it created a world's record by +carrying seven passengers for 1 hour 54 minutes. Sikorsky also +designed several smaller machines, tractor biplanes on the lines +of the British B.E. type, which were very successful. These +were the only home productions, and the imports consisted mainly +of French aeroplanes by the hundred, which got as far as the +docks and railway sidings and stayed there, while German +influence and the corruption that ruined the Russian Army helped +to lose the War. A few Russian aircraft factories were got into +operation as hostilities proceeded, but their products were +negligible, and it is not on record that Russia ever learned to +manufacture a magneto. + +The United States paid tribute to British efficiency by adopting +the British system of training for its pilots; 500 American +cadets were trained at the School of Military Aeronautics at +oxford, in order to form a nucleus for the American aviation +schools which were subsequently set up in the United States and +in France. As regards production of craft, the designing of the +Liberty engine and building of over 20,000 aeroplanes within a +year proves that America is a manufacturing country, even under +the strain of war. + +There were three years of struggle for aerial supremacy, the +combatants being England and France against Germany, and the +contest was neck and neck all the way. Germany led at the +outset with the standardised two-seater biplanes manned by +pilots and observers, whose training was superior to that +afforded by any other nation, while the machines themselves were +better equipped and fitted with accessories. All the early +German aeroplanes were designated Taube by the uninitiated, and +were formed with swept-back, curved wings very much resembling +the wings of a bird. These had obvious disadvantages, but the +standardisation of design and mass production of the German +factories kept them in the field for a considerable period, and +they flew side by side with tractor biplanes of improved design. +For a little time, the Fokker monoplane became a definite threat +both to French and British machines. It was an improvement on +the Morane French monoplane, and with a high-powered engine it +climbed quickly and flew fast, doing a good deal of damage for a +brief period of 1915. Allied design got ahead of it and finally +drove it out of the air. + +German equipment at the outset, which put the Allies at a +disadvantage, included a hand-operated magneto engine-starter +and a small independent screw which, mounted on one of the main +planes, drove the dynamo used for the wireless set. Cameras +were fitted on practically every machine; equipment included +accurate compasses and pressure petrol gauges, speed and height +recording instruments, bomb-dropping fittings and sectional +radiators which facilitated repairs and gave maximum engine +efficiency in spite of variations of temperature. As counter to +these, the Allied pilots had resource amounting to impudence. +In the early days they carried rifles and hand grenades and +automatic pistols. They loaded their machines down, often at +their own expense, with accessories and fittings until their +aeroplanes earned their title of Christmas trees. They played +with death in a way that shocked the average German pilot of the +War's early stages, declining to fight according to rule and +indulging in the individual duels of the air which the German +hated. As Sir John French put it in one of his reports, they +established a personal ascendancy over the enemy, and in this +way compensated for their inferior material. + +French diversity of design fitted in well with the initiative +and resource displayed by the French pilots. The big Caudron +type was the ideal bomber of the early days; Farman machines +were excellent for reconnaissance and artillery spotting; the +Bleriots proved excellent as fighting scouts and for aerial +photography; the Nieuports made good fighters, as did the Spads, +both being very fast craft, as were the Morane-Saulnier +monoplanes, while the big Voisin biplanes rivalled the Caudron +machines as bombers. + +The day of the Fokker ended when the British B.E.2.C. aeroplane +came to France in good quantities, and the F.E. type, together +with the De Havilland machines, rendered British aerial +superiority a certainty. Germany's best reply--this was about +1916--was the Albatross biplane, which was used by Captain Baron +von Richthofen for his famous travelling circus, manned by +German star pilots and sent to various parts of the line to +hearten up German troops and aviators after any specially bad +strafe. Then there were the Aviatik biplane and the Halberstadt +fighting scout, a cleanly built and very fast machine with a +powerful engine with which Germany tried to win back superiority +in the third year of the War, but Allied design kept about three +months ahead of that of the enemy, once the Fokker had been +mastered, and the race went on. Spads and Bristol fighters, +Sopwith scouts and F.E.'s played their part in the race, and +design was still advancing when peace came. + +The giant twin-engined Handley-Page bomber was tried out, proved +efficient, and justly considered better than anything of its +kind that had previously taken the field. Immediately after the +conclusion of its trials, a specimen of the type was delivered +intact at Lille for the Germans to copy, the innocent pilot +responsible for the delivery doing some great disservice to his +own cause. The Gotha Wagon-Fabrik Firm immediately set to work +and copied the Handley-Page design, producing the great Gotha +bombing machine which was used in all the later raids on England +as well as for night work over the Allied lines. + +How the War advanced design may be judged by comparison of the +military requirements given for the British Military Trials of +1912, with performances of 1916 and 1917, when the speed of the +faster machines had increased to over 150 miles an hour and +Allied machines engaged enemy aircraft at heights ranging up to +22,000 feet. All pre-war records of endurance, speed, and climb +went by the board, as the race for aerial superiority went on. + +Bombing brought to being a number of crude devices in the first +year of the War. Allied pilots of the very early days carried up +bombs packed in a small box and threw them over by hand, while, a +little later, the bombs were strung like apples on wings and +undercarriage, so that the pilot who did not get rid of his load +before landing risked an explosion. Then came a properly +designed carrying apparatus, crude but fairly efficient, and with +1916 development had proceeded as far as the proper bomb-racks +with releasing gear. + +Reconnaissance work developed, so that fighting machines went as +escort to observing squadrons and scouting operations were +undertaken up to 100 miles behind the enemy lines; out of this +grew the art of camouflage, when ammunition dumps were painted +to resemble herds of cows, guns were screened by foliage or +painted to merge into a ground scheme, and many other schemes +were devised to prevent aerial observation. Troops were moved by +night for the most part, owing to the keen eyes of the air +pilots and the danger of bombs, though occasionally the aviator +had his chance. There is one story concerning a British pilot +who, on returning from a reconnaissance flight, observed a +German Staff car on the road under him; he descended and bombed +and machine--gunned the car until the German General and his +chauffeur abandoned it, took to their heels, and ran like +rabbits. Later still, when Allied air superiority was assured, +there came the phase of machine-gunning bodies of enemy troops +from the air. Disregarding all antiaircraft measures, machines +would sweep down and throw battalions into panic or upset the +military traffic along a road, demoralising a battery or a +transport train and causing as much damage through congestion of +traffic as with their actual machine-gun fire. Aerial +photography, too, became a fine art; the ordinary long focus +cameras were used at the outset with automatic plate changers, +but later on photographing aeroplanes had cameras of wide angle +lens type built into the fuselage. These were very simply +operated, one lever registering the exposure and changing the +plate. In many cases, aerial photographs gave information which +the human eye had missed, and it is noteworthy that photographs +of ground showed when troops had marched over it, while the +aerial observer was quite unable to detect the marks left by +their passing. + +Some small mention must be made of seaplane activities, which, +round the European coasts involved in the War, never ceased. +The submarine campaign found in the spotting seaplane its +greatest deterrent, and it is old news now how even the deeply +submerged submarines were easily picked out for destruction from +a height and the news wirelessed from seaplane to destroyer, +while in more than one place the seaplane itself finished the +task by bomb dropping. It was a seaplane that gave Admiral +Beatty the news that the whole German Fleet was out before the +Jutland Battle, news which led to a change of plans that very +nearly brought about the destruction of Germany's naval power. +For the most part, the seaplanes of the War period were heavier +than the land machines and, in the opinion of the land pilots, +were slow and clumsy things to fly. This was inevitable, for +their work demanded more solid building and greater reliability. +To put the matter into Hibernian phrase, a forced landing at sea +is a much more serious matter than on the ground. Thus there +was need for greater engine power, bigger wingspread to support +the floats, and fuel tanks of greater capacity. The flying +boats of the later War period carried considerable crews, were +heavily armed, capable of withstanding very heavy weather, and +carried good loads of bombs on long cruises. Their work was not +all essentially seaplane work, for the R.N.A.S. was as well +known as hated over the German airship sheds in Belgium and +along the Flanders coast. As regards other theatres of War, +they rendered valuable service from the Dardanelles to the +Rufiji River, at this latter place forming a principal factor in +the destruction of the cruiser Konigsberg. Their spotting work +at the Dardanelles for the battleships was responsible for +direct hits from 15 in. guns on invisible targets at ranges of +over 12,000 yards. Seaplane pilots were bombing specialists, +including among their targets army headquarters, ammunition +dumps, railway stations, submarines and their bases, docks, +shipping in German harbours, and the German Fleet at +Wilhelmshaven. Dunkirk, a British seaplane base, was a sharp +thorn in the German side. + +Turning from consideration of the various services to the +exploits of the men composing them, it is difficult to +particularise. A certain inevitable prejudice even at this +length of time leads one to discount the valour of pilots in the +German Air Service, but the names of Boelcke, von Richthofen, +and Immelmann recur as proof of the courage that was not wanting +in the enemy ranks, while, however much we may decry the Gotha +raids over the English coast and on London, there is no doubt +that the men who undertook these raids were not deficient in the +form of bravery that is of more value than the unthinking valour +of a minute which, observed from the right quarter, wins a +military decoration. + +Yet the fact that the Allied airmen kept the air at all in the +early days proved on which side personal superiority lay, for +they were outnumbered, out-manoeuvred, and faced by better +material than any that they themselves possessed; yet they won +their fights or died. The stories of their deeds are endless; +Bishop, flying alone and meeting seven German machines and +crashing four; the battle of May 5th, 1915, when five heroes +fought and conquered twenty-seven German machines, ranging in +altitude between 12,000 and 3,000 feet, and continuing the +extraordinary struggle from five until six in the evening. +Captain Aizlewood, attacking five enemy machines with such +reckless speed that he rammed one and still reached his +aerodrome safely--these are items in a long list of feats of +which the character can only be realised when it is fully +comprehended that the British Air Service accounted for some +8,ooo enemy machines in the course of the War. Among the French +there was Captain Guynemer, who at the time of his death had +brought down fifty-four enemy machines, in addition to many +others of which the destruction could not be officially +confirmed. There was Fonck, who brought down six machines in +one day, four of them within two minutes. + +There are incredible stories, true as incredible, of shattered +men carrying on with their work in absolute disregard of +physical injury. Major Brabazon Rees, V.C., engaged a big +German battle-plane in September of 1915 and, single-handed, +forced his enemy out of action. Later in his career, with a +serious wound in the thigh from which blood was pouring, he kept +up a fight with an enemy formation until he had not a round of +ammunition left, and then returned to his aerodrome to get his +wound dressed. Lieutenants Otley and Dunning, flying in the +Balkans, engaged a couple of enemy machines and drove them off, +but not until their petrol tank had got a hole in it and Dunning +was dangerously wounded in the leg. Otley improvised a +tourniquet, passed it to Dunning, and, when the latter had +bandaged himself, changed from the observer's to the pilot's +seat, plugged the bullet hole in the tank with his thumb and +steered the machine home. + +These are incidents; the full list has not been, and can never +be recorded, but it goes to show that in the pilot of the War +period there came to being a new type of humanity, a product of +evolution which fitted a certain need. Of such was Captain +West, who, engaging hostile troops, was attacked by seven +machines. Early in the engagement, one of his legs was +partially severed by an explosive bullet and fell powerless into +the controls, rendering the machine for the time unmanageable. +Lifting his disabled leg, he regained control of the machine, +and although wounded in the other leg, he manoeuvred his machine +so skilfully that his observer was able to get several good +bursts into the enemy machines, driving them away. Then, +desperately wounded as he was, Captain West brought the machine +over to his own lines and landed safely. He fainted from loss +of blood and exhaustion, but on regaining consciousness, +insisted on writing his report. Equal to this was the exploit +of Captain Barker, who, in aerial combat, was wounded in the +right and left thigh and had his left arm shattered, +subsequently bringing down an enemy machine in flames, and then +breaking through another hostile formation and reaching the +British lines. + +In recalling such exploits as these, one is tempted on and on, +for it seems that the pilots rivalled each other in their +devotion to duty, this not confined to British aviators, but +common practically to all services. Sufficient instances have +been given to show the nature of the work and the character of +the men who did it. + +The rapid growth of aerial effort rendered it necessary in +January of 1915 to organise the Royal Flying Corps into +separate wings, and in October of the same year it was +constituted in Brigades. In 1916 the Air Board was formed, +mainly with the object of co-ordinating effort and ensuring both +to the R.N.A.S. and to the R.F.C. adequate supplies of material +as far as construction admitted. Under the presidency of Lord +Cowdray, the Air Board brought about certain reforms early in +1917, and in November of that year a separate Air Ministry was +constituted, separating the Air Force from both Navy and Army, +and rendering it an independent force. On April 1st, 1918, the +Royal Air Force came into existence, and unkind critics in the +Royal Flying Corps remarked on the appropriateness of the date. +At the end of the War, the personnel of the Royal Air Force +amounted to 27,906 officers, and 263,842 other ranks. Contrast +of these figures with the number of officers and men who took +the field in 1914 is indicative of the magnitude of British +aerial effort in the War period. + + + +XX. THE WAR PERIOD--II + +There was when War broke out no realisation on the part of the +British Government of the need for encouraging the enterprise of +private builders, who carried out their work entirely at +their-own cost. The importance of a supply of British-built +engines was realised before the War, it is true, and a +competition was held in which a prize of L5,000 was offered for +the best British engine, but this awakening was so late that the +R.F.C. took the field without a single British power plant. +Although Germany woke up equally late to the need for home +produced aeroplane engines, the experience gained in building +engines for dirigibles sufficed for the production of aeroplane +power plants. The Mercedes filled all requirements together +with the Benz and the Maybach. There was a 225 horsepower Benz +which was very popular, as were the 100 horse-power and 170 +horse-power Mercedes, the last mentioned fitted to the Aviatik +biplane of 1917. The Uberursel was a copy of the Gnome and +supplied the need for rotary engines. + +In Great Britain there were a number of aeroplane constructing +firms that had managed to emerge from the lean years 1912-1913 +with sufficient manufacturing plant to give a hand in making up +the leeway of construction when War broke out. Gradually the +motor-car firms came in, turning their body-building departments +to plane and fuselage construction, which enabled them to turn +out the complete planes engined and ready for the field. The +coach-building trade soon joined in and came in handy as +propeller makers; big upholstering and furniture firms and scores +of concerns that had never dreamed of engaging in aeroplane +construction were busy on supplying the R.F.C. By 1915 hundreds +of different firms were building aeroplanes and parts; by 1917 +the number had increased to over 1,000, and a capital of over a +million pounds for a firm that at the outbreak of War had +employed a score or so of hands was by no means uncommon. Women +and girls came into the work, more especially in plane +construction and covering and doping, though they took their +place in the engine shops and proved successful at acetylene +welding and work at the lathes. It was some time before Britain +was able to provide its own magnetos, for this key industry had +been left in the hands of the Germans up to the outbreak of War, +and the 'Bosch' was admittedly supreme--even now it has never +been beaten, and can only be equalled, being as near perfection +as is possible for a magneto. + +One of the great inventions of the War was the synchronisation +of engine-timing and machine gun, which rendered it possible to +fire through the blades of a propeller without damaging them, +though the growing efficiency of the aeroplane as a whole and of +its armament is a thing to marvel at on looking back and +considering what was actually accomplished. As the efficiency +of the aeroplane increased, so anti-aircraft guns and +range-finding were improved. Before the War an aeroplane +travelling at full speed was reckoned perfectly safe at 4,000 +feet, but, by the first month of 1915, the safe height had gone +up to 9,000 feet, 7,000 feet being the limit of rifle and machine +gun bullet trajectory; the heavier guns were not sufficiently +mobile to tackle aircraft. At that time, it was reckoned that +effective aerial photography ceased at 6,000 feet, while +bomb-dropping from 7,000-8,000 feet was reckoned uncertain except +in the case of a very large target. The improvement in +anti-aircraft devices went on, and by May of 1916, an aeroplane +was not safe under 15,000 feet, while anti-aircraft shells had +fuses capable of being set to over 20,000 feet, and bombing from +15,000 and 16,000 feet was common. It was not till later that +Allied pilots demonstrated the safety that lies in flying very +near the ground, this owing to the fact that, when flying swiftly +at a very low altitude, the machine is out of sight almost before +it can be aimed at. + +The Battle of the Somme and the clearing of the air preliminary +to that operation brought the fighting aeroplane pure and simple +with them. Formations of fighting planes preceded reconnaissance +craft in order to clear German machines and observation balloons +out of the sky and to watch and keep down any further enemy +formations that might attempt to interfere with Allied +observation work. The German reply to this consisted in the +formation of the Flying Circus, of which Captain Baron von +Richthofen's was a good example. Each circus consisted of a +large formation of speedy machines, built specially for fighting +and manned by the best of the German pilots. These were sent to +attack at any point along the line where the Allies had got a +decided superiority. + +The trick flying of pre-war days soon became an everyday matter; +Pegoud astonished the aviation world before the War by first +looping the loop, but, before three years of hostilities had +elapsed, looping was part of the training of practically every +pilot, while the spinning nose dive, originally considered fatal, +was mastered, and the tail slide, which consisted of a machine +rising nose upward in the air and falling back on its tail, +became one of the easiest 'stunts' in the pilot's repertoire. +Inherent stability was gradually improved, and, from 1916 onward, +practically every pilot could carry on with his machine-gun or +camera and trust to his machine to fly itself until he was free +to attend to it. There was more than one story of a machine +coming safely to earth and making good landing on its own account +with the pilot dead in his cock-pit. + +Toward the end of the War, the Independent Air Force was formed +as a branch of the R.A.F. with a view to bombing German bases +and devoting its attention exclusively to work behind the enemy +lines. Bombing operations were undertaken by the R.N.A.S. as +early as 1914-1915 against Cuxhaven, Dusseldorf, and +Friedrichshavn, but the supply of material was not sufficient to +render these raids continuous. A separate Brigade, the 8th, was +formed in 1917 to harass the German chemical and iron +industries, the base being in the Nancy area, and this policy +was found so fruitful that the Independent Force was constituted +on the 8th June, 1918. The value of the work accomplished by +this force is demonstrated by the fact that the German High +Command recalled twenty fighting squadrons from the Western +front to counter its activities, and, in addition, took troops +away from the fighting line in large numbers for manning +anti-aircraft batteries and searchlights. The German press of +the last year of the War is eloquent of the damage done in +manufacturing areas by the Independent Force, which, had +hostilities continued a little longer, would have included Berlin +in its activities. + +Formation flying was first developed by the Germans, who made +use of it in the daylight raids against England in 1917. Its +value was very soon realised, and the V formation of wild geese +was adopted, the leader taking the point of the V and his +squadron following on either side at different heights. The air +currents set up by the leading machines were thus avoided by +those in the rear, while each pilot had a good view of the +leader's bombs, and were able to correct their own aim by the +bursts, while the different heights at which they flew rendered +anti-aircraft gun practice less effective. Further, machines +were able to afford mutual protection to each other and any +attacker would be met by machine-gun fire from three or four +machines firing on him from different angles and heights. In +the later formations single-seater fighters flew above the +bombers for the purpose of driving off hostile craft. Formation +flying was not fully developed when the end of the War brought +stagnation in place of the rapid advance in the strategy and +tactics of military air work. + + + +XXI. RECONSTRUCTION + +The end of the War brought a pause in which the multitude of +aircraft constructors found themselves faced with the possible +complete stagnation of the industry, since military activities +no longer demanded their services and the prospects of +commercial flying were virtually nil. That great factor in +commercial success, cost of plant and upkeep, had received no +consideration whatever in the War period, for armies do not +count cost. The types of machines that had evolved from the War +were very fast, very efficient, and very expensive, although the +bombers showed promise of adaptation to commercial needs, and, +so far as other machines were concerned, America had already +proved the possibilities of mail-carrying by maintaining a mail +service even during the War period. + +A civil aviation department of the Air Ministry was formed in +February of 1919 with a Controller General of Civil Aviation +at the head. This was organised into four branches, one dealing +with the survey and preparation of air routes for the British +Empire, one organising meteorological and wireless telegraphy +services, one dealing with the licensing of aerodromes, machines +for passenger or goods carrying and civilian pilots, and one +dealing with publicity and transmission of information +generally. A special Act of Parliament 264 entitled 'The Air +Navigation Acts, 1911-1919,' was passed on February 27th, and +commercial flying was officially permitted from May 1st, 1919. + +Meanwhile the great event of 1919, the crossing of the +Atlantic by air, was gradually ripening to performance. In +addition to the rigid airship, R.34, eight machines entered for +this flight, these being a Short seaplane, Handley-Page, +Martinsyde, Vickers-Vimy, and Sopwith aeroplanes, and three +American flying boats, N.C.1, N.C.3, and N.C.4. The Short +seaplane was the only one of the eight which proposed to make +the journey westward; in flying from England to Ireland, before +starting on the long trip to Newfoundland, it fell into the sea +off the coast of Anglesey, and so far as it was concerned the +attempt was abandoned. + +The first machines to start from the Western end were the three +American seaplanes, which on the morning of May 6th left +Trepassy, Newfoundland, on the 1,380 mile stage to Horta in the +Azores. N.C.1 and N.C.3 gave up the attempt very early, but +N.C.4, piloted by Lieut.-Commander Read, U.S.N., made Horta on +May 17th and made a three days' halt. On the 20th the second +stage of the journey to Ponta Delgada, a further 190 miles, was +completed and a second halt of a week was made. On the 27th, +the machine left for Lisbon, 900 miles distant, and completed +the journey in a day. On the 30th a further stage of 340 miles +took N.C.4 on to Ferrol, and the next day the last stage of 420 +miles to Plymouth was accomplished. + +Meanwhile, H. G. Hawker, pilot of the Sopwith biplane, together +with Commander Mackenzie Grieve, R.N., his navigator, found the +weather sufficiently auspicious to set out at 6.48 p.m. On +Sunday, May 18th, in the hope of completing the trip by the +direct route before N.C.4 could reach Plymouth. They set out +from Mount Pearl aerodrome, St John's, Newfoundland, and vanished +into space, being given up as lost, as Hamel was lost immediately +before the War in attempting to fly the North Sea. There was a +week of dead silence regarding their fate, but on the following +Sunday morning there was world-wide relief at the news that the +plucky attempt had not ended in disaster, but both aviators had +been picked up by the steamer Mary at 9.30 a.m. on the morning of +the 19th, while still about 750 miles short of the conclusion of +their journey. Engine failure brought them down, and they planed +down to the sea close to the Mary to be picked up; as the vessel +was not fitted with wireless, the news of their rescue could not +be communicated until land was reached. An equivalent of half +the L10,000 prize offered by the Daily Mail for the non-stop +flight was presented by the paper in recognition of the very +gallant attempt, and the King conferred the Air Force Cross on +both pilot and navigator. + +Raynham, pilot of the Martinsyde competing machine, had the bad +luck to crash his craft twice in attempting to start before he +got outside the boundary of the aerodrome. The Handley-Page +machine was withdrawn from the competition, and, attempting to +fly to America, was crashed on the way. + +The first non-stop crossing was made on June 14th-15th in 16 +hours 27 minutes, the speed being just over 117 miles per hour. +The machine was a Vickers-Vimy bomber, engined with two +Rolls-Royce Eagle VIII's, piloted by Captain John Alcock, D.S.C., +with Lieut. Arthur Whitten-Brown as navigator. The journey was +reported to be very rough, so much so at times that Captain +Alcock stated that they were flying upside down, and for the +greater part of the time they were out of sight of the sea. Both +pilot and navigator had the honour of knighthood conferred on +them at the conclusion of the journey. + +Meanwhile, commercial flying opened on May 8th (the official +date was May 1st) with a joy-ride service from Hounslow of Avro +training machines. The enterprise caught on remarkably, and the +company extended their activities to coastal resorts for the +holiday season--at Blackpool alone they took up 10,000 +passengers before the service was two months old. Hendon, +beginning passenger flights on the same date, went in for +exhibition and passenger flying, and on June 21st the aerial +Derby was won by Captain Gathergood on an Airco 4R machine with +a Napier 450 horse-power 'Lion' engine; incidentally the speed +of 129.3 miles per hour was officially recognised as constituting +the world's record for speed within a closed circuit. On July +17th a Fiat B.R. biplane with a 700 horse-power engine landed at +Kenley aerodrome after having made a non-stop flight of 1,100 +miles. The maximum speed of this machine was 160 miles per +hour, and it was claimed to be the fastest machine in existence. +On August 25th a daily service between London and Paris was +inaugurated by the Aircraft Manufacturing Company, Limited, who +ran a machine each way each day, starting at 12.30 and due to +arrive at 2.45 p.m. The Handley-Page Company began a similar +service in September of 1919, but ran it on alternate days +with machines capable of accommodating ten passengers. The +single fare in each case was fixed at 15 guineas and the parcel +rate at 7s. 6d. per pound. + +Meanwhile, in Germany, a number of passenger services had been +in operation from the early part of the year; the Berlin-Weimar +service was established on February 5th and Berlin-Hamburg on +March 1st, both for mail and passenger carrying. Berlin-Breslau +was soon added, but the first route opened remained most +popular, 538 flights being made between its opening and the +end of April, while for March and April combined, the +Hamburg-Berlin route recorded only 262 flights. All three +routes were operated by a combine of German aeronautical firms +entitled the Deutsch Luft Rederie. The single fare between +Hamburg and Berlin was 450 marks, between Berlin and Breslau 500 +marks, and between Berlin and Weimar 450 marks. Luggage was +carried free of charge, but varied according to the weight of +the passenger, since the combined weight of both passenger and +luggage was not allowed to exceed a certain limit. + +In America commercial flying had begun in May of 1918 with the +mail service between Washington, Philadelphia, and New York, +which proved that mail carrying is a commercial possibility, and +also demonstrated the remarkable reliability of the modern +aeroplane by making 102 complete flights out of a possible total +of 104 in November, 1918, at a cost of 0.777 of a dollar per +mile. By March of 1919 the cost per mile had gone up to 1.28 +dollars; the first annual report issued at the end of May showed +an efficiency of 95.6 per cent and the original six aeroplanes +and engines with which the service began were still in regular +use. + +In June of 1919 an American commercial firm chartered an +aeroplane for emergency service owing to a New York harbour +strike and found it so useful that they made it a regular +service. The Travellers Company inaugurated a passenger flying +boat service between New York and Atlantic City on July 25th, the +fare, inclusive of 35 lbs. of luggage, being fixed at L25 each +way. + +Five flights on the American continent up to the end of 1919 +are worthy of note. On December 13th, 1918, Lieut. D. Godoy of +the Chilian army left Santiago, Chili, crossed the Andes at a +height of 19,700 feet and landed at Mendoza, the capital of the +wine-growing province of Argentina. On April 19th, 1919, Captain +E. F. White made the first non-stop flight between New York and +Chicago in 6 hours 50 minutes on a D.H.4 machine driven by a +twelve-cylinder Liberty engine. Early in August Major Schroeder, +piloting a French Lepere machine flying at a height of 18,400 +feet, reached a speed of 137 miles per hour with a Liberty motor +fitted with a super-charger. Toward the end of August, Rex +Marshall, on a Thomas-Morse biplane, starting from a height of +17,000 feet, made a glide of 35 miles with his engine cut off, +restarting it when at a height of 600 feet above the ground. +About a month later R. Rohlfe, piloting a Curtiss triplane, broke +the height record by reaching 34,610 feet. + + + +XXII. 1919-20 + +Into the later months of 1919 comes the flight by Captain +Ross-Smith from England to Australia and the attempt to make the +Cape to Cairo voyage by air. The Australian Government had +offered a prize of L10,000 for the first flight from England to +Australia in a British machine, the flight to be accomplished in +720 consecutive hours. Ross-Smith, with his brother, Lieut. +Keith Macpherson Smith, and two mechanics, left Hounslow in a +Vickers-Vimy bomber with Rolls-Royce engine on November 12th and +arrived at Port Darwin, North Australia, on the 10th December, +having completed the flight in 27 days 20 hours 20 minutes, thus +having 51 hours 40 minutes to spare out of the 720 allotted +hours. + +Early in 1920 came a series of attempts at completing the +journey by air between Cairo and the Cape. Out of four +competitors Colonel Van Ryneveld came nearest to making the +journey successfully, leaving England on a standard Vickers-Vimy +bomber with Rolls-Royce engines, identical in design with the +machine used by Captain Ross-Smith on the England to Australia +flight. A second Vickers-Vimy was financed by the Times +newspaper and a third flight was undertaken with a Handley-Page +machine under the auspices of the Daily Telegraph. The Air +Ministry had already prepared the route by means of three survey +parties which cleared the aerodromes and landing grounds, +dividing their journey into stages of 200 miles or less. Not +one of the competitors completed the course, but in both this +and Ross-Smith's flight valuable data was gained in respect of +reliability of machines and engines, together with a mass of +meteorological information. + +The Handley-Page Company announced in the early months of 1920 +that they had perfected a new design of wing which brought about +a twenty to forty per cent improvement in lift rate in the year. +When the nature of the design was made public, it was seen to +consist of a division of the wing into small sections, each with +its separate lift. A few days later, Fokker, the Dutch +inventor, announced the construction of a machine in which all +external bracing wires are obviated, the wings being of a very +deep section and self-supporting. The value of these two +inventions remains to be seen so far as commercial flying is +concerned. + +The value of air work in war, especially so far as the Colonial +campaigns in which British troops are constantly being engaged is +in question, was very thoroughly demonstrated in a report issued +early in 1920 with reference to the successful termination of the +Somaliland campaign through the intervention of the Royal Air +Force, which between January 21st and the 31st practically +destroyed the Dervish force under the Mullah, which had been a +thorn in the side of Britain since 1907. Bombs and machine-guns +did the work, destroying fortifications and bringing about the +surrender of all the Mullah's following, with the exception of +about seventy who made their escape. + +Certain records both in construction and performance had +characterised the post-war years, though as design advances and +comes nearer to perfection, it is obvious that records must get +fewer and farther between. The record aeroplane as regards size +at the time of its construction was the Tarrant triplane, which +made its first--and last--flight on May 28th, 1919. The total +loaded weight was 30 tons, and the machine was fitted with six +400 horse-power engines; almost immediately after the trial +flight began, the machine pitched forward on its nose and was +wrecked, causing fatal injuries to Captains Dunn and Rawlings, +who were aboard the machine. A second accident of similar +character was that which befell the giant seaplane known as the +Felixstowe Fury, in a trial flight. This latter machine was +intended to be flown to Australia, but was crashed over the +water. + +On May 4th, 1920, a British record for flight duration and +useful load was established by a commercial type Handley-Page +biplane, which, carrying a load of 3,690 lbs., rose to a height +of 13,999 feet and remained in the air for 1 hour 20 minutes. +On May 27th the French pilot, Fronval, flying at Villacoublay in +a Morane-Saulnier type of biplane with Le Rhone motor, put up an +extraordinary type of record by looping the loop 962 times in 3 +hours 52 minutes 10 seconds. Another record of the year of +similar nature was that of two French fliers, Boussotrot and +Bernard, who achieved a continuous flight of 24 hours 19 minutes +7 seconds, beating the pre-war record of 21 hours 48 3/4 seconds +set up by the German pilot, Landemann. Both these records are +likely to stand, being in the nature of freaks, which demonstrate +little beyond the reliability of the machine and the capacity for +endurance on the part of its pilots. + +Meanwhile, on February 14th, Lieuts. Masiero and Ferrarin left +Rome on S.V.A. Ansaldo V. machines fitted with 220 horse-power +S.V.A. motors. On May 30th they arrived at Tokio, having flown +by way of Bagdad, Karachi, Canton, Pekin, and Osaka. Several +other competitors started, two of whom were shot down by Arabs in +Mesopotamia. + +Considered in a general way, the first two years after the +termination of the Great European War form a period of transition +in which the commercial type of aeroplane was gradually evolved +from the fighting machine which was perfected in the four +preceding years. There was about this period no sense of +finality, but it was as experimental, in its own way, as were the +years of progressing design which preceded the war period. Such +commercial schemes as were inaugurated call for no more note than +has been given here; they have been experimental, and, with the +possible exception of the United States Government mail service, +have not been planned and executed on a sufficiently large scale +to furnish reliable data on which to forecast the prospects of +commercial aviation. And there is a school rapidly growing up +which asserts that the day of aeroplanes is nearly over. The +construction of the giant airships of to-day and the successful +return flight of R34 across the Atlantic seem to point to the +eventual triumph, in spite of its disadvantages, of the dirigible +airship. + +This is a hard saying for such of the aeroplane industry as +survived the War period and consolidated itself, and it is but +the saying of a section which bases its belief on the fact that, +as was noted in the very early years of the century, the +aeroplane is primarily a war machine. Moreover, the experience +of the War period tended to discredit the dirigible, since, +before the introduction of helium gas, the inflammability of its +buoyant factor placed it at an immense disadvantage beside the +machine dependent on the atmosphere itself for its lift. + +As life runs to-day, it is a long time since Kipling wrote his +story of the airways of a future world and thrust out a prophecy +that the bulk of the world's air traffic would be carried by +gas-bag vessels. If the school which inclines to belief in the +dirigible is right in its belief, as it well may be, then the +foresight was uncannily correct, not only in the matter of the +main assumption, but in the detail with which the writer +embroidered it. + +On the constructional side, the history of the aeroplane is +still so much in the making that any attempt at a critical +history would be unwise, and it is possible only to record fact, +leaving it to the future for judgment to be passed. But, in a +general way, criticism may be advanced with regard to the place +that aeronautics takes in civilisation. In the past hundred +years, the world has made miraculously rapid strides materially, +but moral development has not kept abreast. Conception of the +responsibilities of humanity remains virtually in a position of +a hundred years ago; given a higher conception of life and its +responsibilities, the aeroplane becomes the crowning achievement +of that long series which James Watt inaugurated, the last step +in intercommunication, the chain with which all nations are +bound in a growing prosperity, surely based on moral wellbeing. +Without such conception of the duties as well as the rights of +life, this last achievement of science may yet prove the weapon +that shall end civilisation as men know it to-day, and bring +this ultra-material age to a phase of ruin on which saner people +can build a world more reasonable and less given to groping +after purely material advancement. + + + +PART II + +1903-1920: PROGRESS IN DESIGN +BY LIEUT.-COL. W. LOCKWOOD MARSH + +I. THE BEGINNINGS + +Although the first actual flight of an aeroplane was made by the +Wrights on December 17th 1903, it is necessary, in considering +the progress of design between that period and the present day, +to go back to the earlier days of their experiments with +'gliders,' which show the alterations in design made by them in +their step-bystep progress to a flying machine proper, and give +a clear idea of the stage at which they had arrived in the art +of aeroplane design at the time of their first flights. + +They started by carefully surveying the work of previous +experimenters, such as Lilienthal and Chanute, and from the +lesson of some of the failures of these pioneers evolved certain +new principles which were embodied in their first glider, built +in 1900. In the first place, instead of relying upon the +shifting of the operator's body to obtain balance, which had +proved too slow to be reliable, they fitted in front of the main +supporting surfaces what we now call an 'elevator,' which could +be flexed, to control the longitudinal balance, from where the +operator lay prone upon the main supporting surfaces. The second +main innovation which they incorporated in this first glider, and +the principle of which is still used in every aeroplane in +existence, was the attainment of lateral balance by warping the +extremities of the main planes. The effect of warping or pulling +down the extremity of the wing on one side was to increase its +lift and so cause that side to rise. In the first two gliders +this control was also used for steering to right and left. Both +these methods of control were novel for other than model work, as +previous experimenters, such as Lilienthal and Pilcher, had +relied entirely upon moving the legs or shifting the position of +the body to control the longitudinal and lateral motions of their +gliders. For the main supporting surfaces of the glider the +biplane system of Chanute's gliders was adopted with certain +modifications, while the curve of the wings was founded upon the +calculations of Lilienthal as to wind pressure and consequent +lift of the plane. + +This first glider was tested on the Kill Devil Hill sand-hills +in North Carolina in the summer of 1900 and proved at any +rate the correctness of the principles of the front elevator and +warping wings, though its designers were puzzled by the fact +that the lift was less than they expected; whilst the 'drag'(as +we call it), or resistance, was also considerably lower than +their predictions. The 1901 machine was, in consequence, nearly +doubled in area--the lifting surface being increased from 165 to +308 square feet--the first trial taking place on July 27th, +1901, again at Kill Devil Hill. It immediately appeared that +something was wrong, as the machine dived straight to the +ground, and it was only after the operator's position had been +moved nearly a foot back from what had been calculated as the +correct position that the machine would glide--and even then the +elevator had to be used far more strongly than in the previous +year's glider. After a good deal of thought the apparent +solution of the trouble was finally found. + +This consisted in the fact that with curved surfaces, while at +large angles the centre of pressure moves forward as the angle +decreases, when a certain limit of angle is reached it travels +suddenly backwards and causes the machine to dive. The Wrights +had known of this tendency from Lilienthal's researches, but had +imagined that the phenomenon would disappear if they used a +fairly lightly cambered--or curved--surface with a very abrupt +curve at the front. Having discovered what appeared to be the +cause they surmounted the difficulty by 'trussing down' the +camber of the wings, with the result that they at once got back +to the old conditions of the previous year and could control the +machine readily with small movements of the elevator, even being +able to follow undulations in the ground. They still found, +however, that the lift was not as great as it should have been; +while the drag remained, as in the previous glider, surprisingly +small. This threw doubt on previous figures as to wind +resistance and pressure on curved surfaces; but at the same time +confirmed (and this was a most important result) Lilienthal's +previously questioned theory that at small angles the pressure +on a curved surface instead of being normal, or at right angles +to, the chord is in fact inclined in front of the perpendicular. +The result of this is that the pressure actually tends to draw +the machine forward into the wind--hence the small amount of +drag, which had puzzled Wilbur and Orville Wright. + +Another lesson which was learnt from these first two years of +experiment, was that where, as in a biplane, two surfaces are +superposed one above the other, each of them has somewhat less +lift than it would have if used alone. The experimenters were +also still in doubt as to the efficiency of the warping method +of controlling the lateral balance as it gave rise to certain +phenomena which puzzled them, the machine turning towards the +wing having the greater angle, which seemed also to touch the +ground first, contrary to their expectations. Accordingly, on +returning to Dayton towards the end of 1901, they set +themselves to solve the various problems which had appeared and +started on a lengthy series of experiments to check the previous +figures as to wind resistance and lift of curved surfaces, +besides setting themselves to grapple with the difficulty of +lateral control. They accordingly constructed for themselves at +their home in Dayton a wind tunnel 16 inches square by 6 feet +long in which they measured the lift and 'drag' of more than two +hundred miniature wings. In the course of these tests they for +the first time produced comparative results of the lift of +oblong and square surfaces, with the result that they +re-discovered the importance of 'aspect ratio'--the ratio of +length to breadth of planes. As a result, in the next year's +glider the aspect ration of the wings was increased from the +three to one of the earliest model to about six to one, which is +approximately the same as that used in the machines of to-day. +Further than that, they discussed the question of lateral +stability, and came to the conclusion that the cause of the +trouble was that the effect of warping down one wing was to +increase the resistance of, and consequently slow down, that +wing to such an extent that its lift was reduced sufficiently to +wipe out the anticipated increase in lift resulting from the +warping. From this they deduced that if the speed of the warped +wing could be controlled the advantage of increasing the angle +by warping could be utilised as they originally intended. They +therefore decided to fit a vertical fin at the rear which, if the +machine attempted to turn, would be exposed more and more to the +wind and so stop the turning motion by offering increased +resistance. + +As a result of this laboratory research work the third Wright +glider, which was taken to Kill Devil Hill in September, 1902, +was far more efficient aerodynamically than either of its two +predecessors, and was fitted with a fixed vertical fin at the +rear in addition to the movable elevator in front. According to +Mr Griffith Brewer,[*] this third glider contained 305 square +feet of surface; though there may possibly be a mistake here, as +he states[**] the surface of the previous year's glider to have +been only 290 square feet, whereas Wilbur Wright himself[***] +states it to have been 308 square feet. The matter is not, +perhaps, save historically, of much importance, except that the +gliders are believed to have been progressively larger, and +therefore if we accept Wilbur Wright's own figure of the surface +of the second glider, the third must have had a greater area +than that given by Mr Griffith Brewer. Unfortunately, no +evidence of the Wright Brothers themselves on this point is +available. + +[*] Fourth Wilbur Wright Memorial Lecture, Aeronautical Journal, +Vol. XX, No. 79, page 75. + +[**] Ibid. page 73. + +[***] Ibid. pp. 91 and 102. + +The first glide of the 1902, season was made on September 17th +of that year, and the new machine at once showed itself an +improvement on its predecessors, though subsequent trials showed +that the difficulty of lateral balance had not been entirely +overcome. It was decided, therefore, to turn the vertical fin +at the rear into a rudder by making it movable. At the same +time it was realised that there was a definite relation between +lateral balance and directional control, and the rudder controls +and wing-warping wires were accordingly connected This ended the +pioneer gliding experiments of Wilbur and Orville Wright--though +further glides were made in subsequent years--as the following +year, 1903, saw the first power-driven machine leave the ground. + +To recapitulate--in the course of these original experiments the +Wrights confirmed Lilienthal's theory of the reversal of the +centre of pressure on cambered surfaces at small angles of +incidence: they confirmed the importance of high aspect ratio +in respect to lift: they had evolved new and more accurate +tables of lift and pressure on cambered surfaces: they were the +first to use a movable horizontal elevator for controlling +height: they were the first to adjust the wings to different +angles of incidence to maintain lateral balance: and they were +the first to use the movable rudder and adjustable wings in +combination. + +They now considered that they had gone far enough to justify +them in building a power-driven 'flier,' as they called their +first aeroplane. They could find no suitable engine and so +proceeded to build for themselves an internal combustion engine, +which was designed to give 8 horse-power, but when completed +actually developed about 12-15 horse-power and weighed 240 lbs. +The complete machine weighed about 750 lbs. Further details of +the first Wright aeroplane are difficult to obtain, and even +those here given should be received with some caution. The +first flight was made on December 17th 1903, and lasted 12 +seconds. Others followed immediately, and the fourth lasted 59 +seconds, a distance of 852 feet being covered against a 20-mile +wind. + +The following year they transferred operations to a field +outside Dayton, Ohio (their home), and there they flew a +somewhat larger and heavier machine with which on September 20th +1904, they completed the first circle in the air. In this +machine for the first time the pilot had a seat; all the +previous experiments having been carried out with the operator +lying prone on the lower wing. This was followed next year by +another still larger machine, and on it they carried out many +flights. During the course of these flights they satisfied +themselves as to the cause of a phenomenon which had puzzled +them during the previous year and caused them to fear that they +had not solved the problem of lateral control. They found that +on occasions--always when on a turn--the machine began to slide +down towards the ground and that no amount of warping could stop +it. Finally it was found that if the nose of the machine was +tilted down a recovery could be effected; from which they +concluded that what actually happened was that the machine, +'owing to the increased load caused by centrifugal force,' had +insufficient power to maintain itself in the air and therefore +lost speed until a point was reached at which the controls +became inoperative. In other words, this was the first +experience of 'stalling on a turn,' which is a danger against +which all embryo pilots have to guard in the early stages of +their training. + +The 1905 machine was, like its predecessors, a biplane with a +biplane elevator in front and a double vertical rudder in rear. +The span was 40 feet, the chord of the wings being 6 feet and +the gap between them about the same. The total area was about +600 square feet which supported a total weight of 925 lbs.; +while the motor was 12 to 15 horse-power driving two propellers +on each side behind the main planes through chains and giving +the machine a speed of about 30 m.p.h. one of these chains was +crossed so that the propellers revolved in opposite directions +to avoid the torque which it was feared would be set up if they +both revolved the same way. The machine was not fitted with a +wheeled undercarriage but was carried on two skids, which also +acted as outriggers to carry the elevator. Consequently, a +mechanical method of launching had to be evolved and the machine +received initial velocity from a rail, along which it was drawn +by the impetus provided by the falling of a weight from a wooden +tower or 'pylon.' As a result of this the Wright aeroplane in +its original form had to be taken back to its starting rail +after each flight, and could not restart from the point of +alighting. Perhaps, in comparison with French machines of more +or less contemporary date (evolved on independent lines in +ignorance of the Americans' work), the chief feature of the +Wright biplane of 1905 was that it relied entirely upon the +skill of the operator for its stability; whereas in France some +attempt was being made, although perhaps not very successfully, +to make the machine automatically stable laterally. The +performance of the Wrights in carrying a loading of some 60 lbs. +per horse-power is one which should not be overlooked. The wing +loading was about 1 1/2 lbs. per square foot. + +About the same time that the Wrights were carrying out their +power-driven experiments, a band of pioneers was quite +independently beginning to approach success in France. In +practically every case, however, they started from a somewhat +different standpoint and took as their basic idea the cellular +(or box) kite. This form of kite, consisting of two superposed +surfaces connected at each end by a vertical panel or curtain of +fabric, had proved extremely successful for man-carrying +purposes, and, therefore, it was little wonder that several minds +conceived the idea of attempting to fly by fitting a series of +box-kites with an engine. The first to achieve success was M. +Santos-Dumont, the famous Brazilian pioneer-designer of airships, +who, on November 12th, 1906, made several flights, the last of +which covered a little over 700 feet. Santos-Dumont's machine +consisted essentially of two box-kites, forming the main wings, +one on each side of the body, in which the pilot stood, and at +the front extremity of which was another movable box-kite to act +as elevator and rudder. The curtains at the ends were intended +to give lateral stability, which was further ensured by setting +the wings slightly inclined upwards from the centre, so that when +seen from the front they formed a wide V. This feature is still +to be found in many aeroplanes to-day and has come to be known +as the 'dihedral.' The motor was at first of 24 horse-power, for +which later a 50 horse-power Antoinette engine was substituted; +whilst a three-wheeled undercarriage was provided, so that the +machine could start without external mechanical aid. The +machine was constructed of bamboo and steel, the weight being as +low as 352 lbs. The span was 40 feet, the length being 33 feet, +with a total surface of main planes of 860 square feet. It will +thus be seen--for comparison with the Wright machine--that the +weight per horse-power (with the 50 horse-power engine) was only +7 lbs., while the wing loading was equally low at 1/2 lb. per +square foot. + +The main features of the Santos-Dumont machine were the box-kite +form of construction, with a dihedral angle on the main planes, +and the forward elevator which could be moved in any direction +and therefore acted in the same way as the rudder at the rear of +the Wright biplane. It had a single propeller revolving in the +centre behind the wings and was fitted with an undercarriage +incorporated in the machine. + +The other chief French experimenters at this period were the +Voisin Freres, whose first two machines--identical in +form--were sold to Delagrange and H. Farman, which has sometimes +caused confusion, the two purchasers being credited with the +design they bought. The Voisins, like the Wrights, based their +designs largely on the experimental work of Lilienthal, Langley, +Chanute, and others, though they also carried out tests on the +lifting properties of aerofoils in a wind tunnel of their own. +Their first machines, like those of Santos-Dumont, showed the +effects of experimenting with box-kites, some of which they had +built for M. Ernest Archdeacon in 1904. In their case the +machine, which was again a biplane, had, like both the others +previously mentioned, an elevator in front--though in this case +of monoplane form--and, as in the Wright, a rudder was fitted in +rear of the main planes. The Voisins, however, fitted a fixed +biplane horizontal 'tail'--in an effort to obtain a measure of +automatic longitudinal stability--between the two surfaces of +which the single rudder worked. For lateral stability they +depended entirely on end curtains between the upper and lower +surfaces of both the main planes and biplane tail surfaces. +They, like Santos-Dumont, fitted a wheeled undercarriage, so +that the machine was self-contained. The Voisin machine, then, +was intended to be automatically stable in both senses; whereas +the Wrights deliberately produced a machine which was entirely +dependent upon the pilot's skill for its stability. The +dimensions of the Voisin may be given for comparative purposes, +and were as follows: Span 33 feet with a chord (width from back +to front) of main planes of 6 1/2 feet, giving a total area of +430 square feet. The 50 horse-power Antoinette engine, which was +enclosed in the body (or 'nacelle ') in the front of which the +pilot sat, drove a propeller behind, revolving between the +outriggers carrying the tail. The total weight, including Farman +as pilot, is given as 1,540 lbs., so that the machine was much +heavier than either of the others; the weight per horse-power +being midway between the Santos-Dumont and the Wright at 31 lbs. +per square foot, while the wing loading was considerably greater +than either at 3 1/2 lbs. per square foot. The Voisin machine +was +experimented with by Farman and Delagrange from about June 1907 +onwards, and was in the subsequent years developed by Farman; and +right up to the commencement of the War upheld the principles of +the box-kite method of construction for training purposes. The +chief modification of the original design was the addition of +flaps (or ailerons) at the rear extremities of the main planes to +give lateral control, in a manner analogous to the wing-warping +method invented by the Wrights, as a result of which the end +curtains between the planes were abolished. An additional +elevator was fitted at the rear of the fixed biplane tail, which +eventually led to the discarding of the front elevator +altogether. During the same period the Wright machine came into +line with the others by the fitting of a wheeled undercarriage +integral with the machine. A fixed horizontal tail was also +added to the rear rudder, to which a movable elevator was later +attached; and, finally, the front elevator was done away with. +It will thus be seen that having started from the very different +standpoints of automatic stability and complete control by the +pilot, the Voisin (as developed in the Farman) and Wright +machines, through gradual evolution finally resulted in +aeroplanes of similar characteristics embodying a modicum of +both features. + +Before proceeding to the next stage of progress mention should +be made of the experimental work of Captain Ferber in France. +This officer carried out a large number of experiments with +gliders contemporarily with the Wrights, adopting--like +them--the Chanute biplane principle. He adopted the front +elevator from the Wrights, but immediately went a step farther +by also fitting a fixed tail in rear, which did not become a +feature of the Wright machine until some seven or eight years +later. He built and appeared to have flown a machine fitted +with a motor in 1905, and was commissioned to go to America by +the French War Office on a secret mission to the Wrights. +Unfortunately, no complete account of his experiments appears to +exist, though it can be said that his work was at least as +important as that of any of the other pioneers mentioned. + + + +II. MULTIPLICITY OF IDEAS + +In a review of progress such as this, it is obviously +impossible, when a certain stage of development has been +reached, owing to the very multiplicity of experimenters, to +continue dealing in anything approaching detail with all the +different types of machines; and it is proposed, therefore, from +this point to deal only with tendencies, and to mention +individuals merely as examples of a class of thought rather than +as personalities, as it is often difficult fairly to allocate +the responsibility for any particular innovation. + +During 1907 and 1908 a new type of machine, in the monoplane, +began to appear from the workshops of Louis Bleriot, Robert +Esnault-Pelterie, and others, which was destined to give rise to +long and bitter controversies on the relative advantages of the +two types, into which it is not proposed to enter here; though +the rumblings of the conflict are still to be heard by +discerning ears. Bleriot's early monoplanes had certain new +features, such as the location of the pilot, and in some cases +the engine, below the wing; but in general his monoplanes, +particularly the famous No. XI on which the first Channel +crossing was made on July 25th, 1909, embodied the main +principles of the Wright and Voisin types, except that the +propeller was in front of instead of behind the supporting +surfaces, and was, therefore, what is called a 'tractor' in +place of the then more conventional 'pusher.' Bleriot aimed at +lateral balance by having the tip of each wing pivoted, though he +soon fell into line with the Wrights and adopted the warping +system. The main features of the design of Esnault-Pelterie's +monoplane was the inverted dihedral (or kathedral as this was +called in Mr S. F. Cody's British Army Biplane of 1907) on the +wings, whereby the tips were considerably lower than the roots at +the body. This was designed to give automatic lateral stability, +but, here again, conventional practice was soon adopted and the +R.E.P. monoplanes, which became well-known in this country +through their adoption in the early days by Messrs Vickers, were +of the ordinary monoplane design, consisting of a tractor +propeller with wire-stayed wings, the pilot being in an enclosed +fuselage containing the engine in front and carrying at its rear +extremity fixed horizontal and vertical surfaces combined with +movable elevators and rudder. Constructionally, the R.E.P. +monoplane was of extreme interest as the body was constructed of +steel. The Antoinette monoplane, so ably flown by Latham, was +another very famous machine of the 1909-1910 period, though its +performance were frequently marred by engine failure; which was +indeed the bugbear of all these early experimenters, and it is +difficult to say, after this lapse of time, how far in many cases +the failures which occurred, both in performances and even in the +actual ability to rise from the ground, were due to defects in +design or merely faults in the primitive engines available. The +Antoinette aroused admiration chiefly through its graceful, +birdlike lines, which have probably never been equalled; but its +chief interest for our present purpose lies in the novel method +of wing-staying which was employed. Contemporary monoplanes +practically all had their wings stayed by wires to a post in the +centre above the fuselage, and, usually, to the undercarriage +below. In the Antoinette, however, a king post was introduced +half-way along the wing, from which wires were carried to the +ends of the wings and the body. This was intended to give +increased strength and permitted of a greater wing-spread and +consequently improved aspect ratio. The same system of +construction was adopted in the British Martinsyde monoplanes of +two or three years later. + +This period also saw the production of the first triplane, which +was built by A. V. Roe in England and was fitted with a J.A.P. +engine of only 9 horse-power--an amazing performance which +remains to this day unequalled. Mr Roe's triplane was chiefly +interesting otherwise for the method of maintaining longitudinal +control, which was achieved by pivoting the whole of the three +main planes so that their angle of incidence could be altered. +This was the direct converse of the universal practice of +elevating by means of a subsidiary surface either in front or +rear of the main planes. + +Recollection of the various flying meetings and exhibitions +which one attended during the years from 1909 to 1911, or even +1912 are chiefly notable for the fact that the first thought on +seeing any new type of machine was not as to what its +'performance'--in speed, lift, or what not--would be; but +speculation as to whether it would leave the ground at all when +eventually tried. This is perhaps the best indication of the +outstanding characteristic of that interim period between the +time of the first actual flights and the later period, +commencing about 1912, when ideas had become settled and it +was at last becoming possible to forecast on the drawing-board +the performance of the completed machine in the air. Without +going into details, for which there is no space here, it is +difficult to convey the correct impression of the chaotic state +which existed as to even the elementary principles of aeroplane +design. All the exhibitions contained large numbers--one had +almost written a majority--of machines which embodied the most +unusual features and which never could, and in practice never +did, leave the ground. At the same time, there were few who +were sufficiently hardy to say certainly that this or that +innovation was wrong; and consequently dozens of inventors in +every country were conducting isolated experiments on both good +and bad lines. All kinds of devices, mechanical and otherwise, +were claimed as the solution of the problem of stability, and +there was even controversy as to whether any measure of +stability was not undesirable; one school maintaining that the +only safety lay in the pilot having the sole say in the attitude +of the machine at any given moment, and fearing danger from the +machine having any mind of its own, so to speak. There was, as +in most controversies, some right on both sides, and when we +come to consider the more settled period from 1912 to the +outbreak of the War in 1914 we shall find how a compromise was +gradually effected. + +At the same time, however, though it was at the time difficult +to pick out, there was very real progress being made, and, +though a number of 'freak' machines fell out by the wayside, the +pioneer designers of those days learnt by a process of trial and +error the right principles to follow and gradually succeeded in +getting their ideas crystallised. + +In connection with stability mention must be made of a machine +which was evolved in the utmost secrecy by Mr J. W. Dunne in a +remote part of Scotland under subsidy from the War office. This +type, which was constructed in both monoplane and biplane form, +showed that it was in fact possible in 1910 and 1911 to design an +aeroplane which could definitely be left to fly itself in the +air. One of the Dunne machines was, for example flown from +Farnborough to Salisbury Plain without any control other than the +rudder being touched; and on another occasion it flew a complete +circle with all controls locked automatically assuming the +correct bank for the radius of turn. The peculiar form of wing +used, the camber of which varied from the root to the tip, gave +rise however, to a certain loss in efficiency, and there was also +a difficulty in the pilot assuming adequate control when desired. +Other machines designed to be stable--such as the German Etrich +and the British Weiss gliders and Handley-Page monoplanes--were +based on the analogy of a wing attached to a certain seed found +in Nature (the 'Zanonia' leaf), on the righting effect of +back-sloped wings combined with upturned (or 'negative') tips. +Generally speaking, however, the machines of the 1909-1912 period +relied for what automatic stability they had on the principle of +the dihedral angle, or flat V, both longitudinally and laterally. +Longitudinally this was obtained by setting the tail at a +slightly smaller angle than the main planes. + +The question of reducing the resistance by adopting 'stream-line' +forms, along which the air could flow uninterruptedly without the +formation of eddies, was not at first properly realised, though +credit should be given to Edouard Nieuport, who in 1909 produced +a monoplane with a very large body which almost completely +enclosed the pilot and made the machine very fast, for those +days, with low horse-power. On one of these machines C. T. +Weyman won the Gordon-Bennett Cup for America in 1911 and +another put up a fine performance in the same race with only a 30 +horse-power engine. The subject, was however, early taken up by +the British Advisory Committee for Aeronautics, which was +established by the Government in 1909, and designers began to +realise the importance of streamline struts and fuselages towards +the end of this transition period. These efforts were at first +not always successful and showed at times a lack of understanding +of the problems involved, but there was a very marked improvement +during the year 1912. At the Paris Aero Salon held early in that +year there was a notable variety of ideas on the subject; whereas +by the time of the one held in October designs had considerably +settled down, more than one exhibitor showing what were called +'monocoque' fuselages completely circular in shape and having +very low resistance, while the same show saw the introduction of +rotating cowls over the propeller bosses, or 'spinners,' as they +came to be called during the War. A particularly fine example of +stream-lining was to be found in the Deperdussin monoplane on +which Vedrines won back the Gordon-Bennett Aviation Cup from +America at a speed of 105.5 m.p.h.--a considerable improvement on +the 78 m.p.h. of the preceding year, which was by no means +accounted for by the mere increase in engine power from 100 +horse-power to 140 horse-power. This machine was the first in +which the refinement of 'stream-lining' the pilot's head, which +became a feature of subsequent racing machines, was introduced. +This consisted of a circular padded excresence above the cockpit +immediately behind the pilot's head, which gradually tapered off +into the top surface of the fuselage. The object was to give the +air an uninterrupted flow instead of allowing it to be broken up +into eddies behind the head of the pilot, and it also provided a +support against the enormous wind-pressure encountered. This +true stream-line form of fuselage owed its introduction to the +Paulhan-Tatin 'Torpille' monoplane of the Paris Salon of early +1917. Altogether the end of the year 1912 began to see the +disappearance of 'freak' machines with all sorts of original +ideas for the increase of stability and performance. Designs had +by then gradually become to a considerable extent standardised, +and it had become unusual to find a machine built which would +fail to fly. The Gnome engine held the field owing to its +advantages, as the first of the rotary type, in lightness and +ease of fitting into the nose of a fuselage. The majority of +machines were tractors (propeller in front) although a +preference, which died down subsequently, was still shown for the +monoplane over the biplane. This year also saw a great increase +in the number of seaplanes, although the 'flying boat' type had +only appeared at intervals and the vast majority were of the +ordinary aeroplane type fitted with floats in place of the land +undercarriage; which type was at that time commonly called +'hydro-aeroplane.' The usual horse power was 50--that of the +smallest Gnome engine--although engines of 100 to 140 horse-power +were also fitted occasionally. The average weight per +horse-power varied from 18 to 25 lbs., while the wing-loading was +usually in the neighbourhood of 5 to 6 lbs. per square foot. The +average speed ranged from 65-75 miles per hour. + + + +III. PROGRESS ON STANDARDISED LINES + +In the last section an attempt has been made to show how, during +what was from the design standpoint perhaps the most critical +period, order gradually became evident out of chaos, +ill-considered ideas dropped out through failure to make good, +and, though there was still plenty of room for improvement in +details, the bulk of the aeroplanes showed a general similarity +in form and conception. There was still a great deal to be +learnt in finding the best form of wing section, and performances +were still low; but it had become definitely possible to say that +flying had emerged from the chrysalis stage and had become a +science. The period which now began was one of scientific +development and improvement--in performance, manoeuvrability, +and general airworthiness and stability. + +The British Military Aeroplane Competition held in the summer of +1912 had done much to show the requirements in design by giving +possibly the first opportunity for a definite comparison of the +performance of different machines as measured by impartial +observers on standard lines--albeit the methods of measuring were +crude. These showed that a high speed--for those days--of 75 +miles an hour or so was attended by disadvantages in the form of +an equally fast low speed, of 50 miles per hour or more, and +generally may be said to have given designers an idea what to aim +for and in what direction improvements were required. In fact, +the most noticeable point perhaps of the machines of this time +was the marked manner in which a machine that was good in one +respect would be found to be wanting in others. It had not yet +been possible to combine several desirable attributes in one +machine. The nearest approach to this was perhaps to be found +in the much discussed Government B.E.2 machine, which was +produced from the Royal Aircraft Factory at Farnborough, in the +summer of 1912. Though considerably criticized from many points +of view it was perhaps the nearest approach to a machine of +all-round efficiency that had up to that date appeared. The +climbing rate, which subsequently proved so important for +military purposes, was still low, seldom, if ever, exceeding 400 +feet per minute; while gliding angles (ratio of descent to +forward travel over the ground with engine stopped) little +exceeded 1 in 8. + +The year 1912 and 1913 saw the subsequently all-conquering +tractor biplane begin to come into its own. This type, which +probably originated in England, and at any rate attained to its +greatest excellence prior to the War from the drawing offices of +the Avro Bristol and Sopwith firms, dealt a blow at the monoplane +from which the latter never recovered. + +The two-seater tractor biplane produced by Sopwith and piloted +by H. G. Hawker, showed that it was possible to produce a +biplane with at least equal speed to the best monoplanes, whilst +having the advantage of greater strength and lower landing +speeds. The Sopwith machine had a top speed of over 80 miles an +hour while landing as slowly as little more than 30 miles an +hour; and also proved that it was possible to carry 3 passengers +with fuel for 4 hours' flight with a motive power of only 80 +horse-power. This increase in efficiency was due to careful +attention to detail in every part, improved wing sections, clean +fuselage-lines, and simplified undercarriages. At the same +time, in the early part of 1913 a tendency manifested itself +towards the four-wheeled undercarriage, a pair of smaller wheels +being added in front of the main wheels to prevent overturning +while running on the ground; and several designs of +oleo-pneumatic and steel-spring undercarriages were produced in +place of the rubber shock-absorber type which had up till then +been almost universal. + +These two statements as to undercarriage designs may appear to +be contradictory, but in reality they do not conflict as they +both showed a greater attention to the importance of good +springing, combined with a desire to avoid complication and a +mass of struts and wires which increased head resistance. + +The Olympia Aero Show of March, 1913, also produced a machine +which, although the type was not destined to prove the best for +the purpose for which it was designed, was of interest as being +the first to be designed specially for war purposes. This was +the Vickers 'Gun-bus,' a 'pusher' machine, with the propeller +revolving behind the main planes between the outriggers carrying +the tail, with a seat right in front for a gunner who was +provided with a machine gun on a swivelling mount which had a +free field of fire in every direction forward. The device which +proved the death-blow for this type of aircraft during the war +will be dealt with in the appropriate place later, but the +machine should not go unrecorded. + +As a result of a number of accidents to monoplanes the +Government appointed a Committee at the end of 1912 to inquire +into the causes of these. The report which was presented in +March, 1913, exonerated the monoplane by coming to the +conclusion that the accidents were not caused by conditions +peculiar to monoplanes, but pointed out certain desiderata in +aeroplane design generally which are worth recording. They +recommended that the wings of aeroplanes should be so internally +braced as to have sufficient strength in themselves not to +collapse if the external bracing wires should give way. The +practice, more common in monoplanes than biplanes, of carrying +important bracing wires from the wings to the undercarriage was +condemned owing to the liability of damage from frequent +landings. They also pointed out the desirability of duplicating +all main wires and their attachments, and of using stranded +cable for control wires. Owing to the suspicion that one +accident at least had been caused through the tearing of the +fabric away from the wing, it was recommended that fabric should +be more securely fastened to the ribs of the wings, and that +devices for preventing the spreading of tears should be +considered. In the last connection it is interesting to note +that the French Deperdussin firm produced a fabric wing-covering +with extra strong threads run at right-angles through the fabric +at intervals in order to limit the tearing to a defined area. + +In spite, however, of the whitewashing of the monoplane by the +Government Committee just mentioned, considerable stir was +occasioned later in the year by the decision of the War office +not to order any more monoplanes; and from this time forward +until the War period the British Army was provided exclusively +with biplanes. Even prior to this the popularity of the +monoplane had begun to wane. At the Olympia Aero Show in March, +1913, biplanes for the first time outnumbered the +'single-deckers'(as the Germans call monoplanes); which had the +effect of reducing the wing-loading. In the case of the +biplanes exhibited this averaged about 4 1/2 lbs. per square +foot, while in the case of the monoplanes in the same exhibition +the lowest was 5 1/2 lbs., and the highest over 8 1/2 lbs. per +square foot of area. It may here be mentioned that it was not +until the War period that the importance of loading per +horse-power was recognised as the true criterion of aeroplane +efficiency, far greater interest being displayed in the amount +of weight borne per unit area of wing. + +An idea of the state of development arrived at about this time +may be gained from the fact that the Commandant of the Military +Wing of the Royal Flying Corps in a lecture before the Royal +Aeronautical Society read in February, 1913, asked for +single-seater scout aeroplanes with a speed of 90 miles an hour +and a landing speed of 45 miles an hour--a performance which +even two years later would have been considered modest in the +extreme. It serves to show that, although higher performances +were put up by individual machines on occasion, the general +development had not yet reached the stage when such performances +could be obtained in machines suitable for military purposes. +So far as seaplanes were concerned, up to the beginning of 1913 +little attempt had been made to study the novel problems +involved, and the bulk of the machines at the Monaco Meeting in +April, 1913, for instance, consisted of land machines fitted with +floats, in many cases of a most primitive nature, without other +alterations. Most of those which succeeded in leaving the water +did so through sheer pull of engine power; while practically all +were incapable of getting off except in a fair sea, which enabled +the pilot to jump the machine into the air across the trough +between two waves. Stability problems had not yet been +considered, and in only one or two cases was fin area added at +the rear high up, to counterbalance the effect of the floats low +down in front. Both twin and single-float machines were used, +while the flying boat was only just beginning to come into being +from the workshops of Sopwith in Great Britain, Borel-Denhaut in +France, and Curtiss in America. In view of the approaching +importance of amphibious seaplanes, mention should be made of the +flying boat (or 'bat boat' as it was called, following Rudyard +Kipling) which was built by Sopwith in 1913 with a wheeled +landing-carriage which could be wound up above the bottom surface +of the boat so as to be out of the way when alighting on water. + +During 1913 the (at one time almost universal) practice +originated by the Wright Brothers, of warping the wings for +lateral stability, began to die out and the bulk of aeroplanes +began to be fitted with flaps (or 'ailerons') instead. This +was a distinct change for the better, as continually warping the +wings by bending down the extremities of the rear spars was +bound in time to produce 'fatigue' in that member and lead to +breakage; and the practice became completely obsolete during the +next two or three years. + +The Gordon-Bennett race of September, 1913, was again won by +a Deperdussin machine, somewhat similar to that of the previous +year, but with exceedingly small wings, only 107 square feet in +area. The shape of these wings was instructive as showing how +what, from the general utility point of view, may be +disadvantageous can, for a special purpose, be turned to +account. With a span of 21 feet, the chord was 5 feet, giving +the inefficient 'aspect ratio' of slightly over 4 to 1 only. +The object of this was to reduce the lift, and therefore the +resistance, to as low a point as possible. The total weight was +1,500 lbs., giving a wing-loading of 14 lbs. per square foot--a +hitherto undreamt-of figure. The result was that the machine +took an enormously long run before starting; and after touching +the ground on landing ran for nearly a mile before stopping; but +she beat all records by attaining a speed of 126 miles per +hour. Where this performance is mainly interesting is in +contrast to the machines of 1920, which with an even higher +speed capacity would yet be able to land at not more than 40 or +50 miles per hour, and would be thoroughly efficient flying +machines. + +The Rheims Aviation Meeting, at which the Gordon-Bennett race +was flown, also saw the first appearance of the Morane 'Parasol' +monoplane. The Morane monoplane had been for some time an +interesting machine as being the only type which had no fixed +surface in rear to give automatic stability, the movable +elevator being balanced through being hinged about one-third of +the way back from the front edge. This made the machine +difficult to fly except in the hands of experts, but it was very +quick and handy on the controls and therefore useful for racing +purposes. In the 'Parasol' the modification was introduced of +raising the wing above the body, the pilot looking out beneath +it, in order to give as good a view as possible. + +Before passing to the year 1914 mention should be made of the +feat performed by Nesteroff, a Russian, and Pegoud, a French +pilot, who were the first to demonstrate the possibilities of +flying upside-down and looping the loop. Though perhaps not +coming strictly within the purview of a chapter on design +(though certain alterations were made to the top wing-bracing of +the machine for this purpose) this performance was of extreme +importance to the development of aviation by showing the +possibility of recovering, given reasonable height, from any +position in the air; which led designers to consider the extra +stresses to which an aeroplane might be subjected and to take +steps to provide for them by increasing strength where +necessary. + +When the year 1914 opened a speed of 126 miles per hour had been +attained and a height of 19,600 feet had been reached. The +Sopwith and Avro (the forerunner of the famous training machine +of the War period) were probably the two leading tractor +biplanes of the world, both two-seaters with a speed variation +from 40 miles per hour up to some 90 miles per hour with 80 +horse-power engines. The French were still pinning their faith +mainly to monoplanes, while the Germans were beginning to come +into prominence with both monoplanes and biplanes of the 'Taube' +type. These had wings swept backward and also upturned at the +wing-tips which, though it gave a certain measure of automatic +stability, rendered the machine somewhat clumsy in the air, and +their performances were not on the whole as high as those of +either France or Great Britain. + +Early in 1914 it became known that the experimental work of +Edward Busk--who was so lamentably killed during an experimental +flight later in the year--following upon the researches of +Bairstow and others had resulted in the production at the Royal +Aircraft Factory at Farnborough of a truly automatically stable +aeroplane. This was the 'R.E.' (Reconnaissance Experimental), a +development of the B.E. which has already been referred to. The +remarkable feature of this design was that there was no +particular device to which one could point out as the cause of +the stability. The stable result was attained simply by detailed +design of each part of the aeroplane, with due regard to its +relation to, and effect on, other parts in the air. Weights and +areas were so nicely arranged that under practically any +conditions the machine tended to right itself. It did not, +therefore, claim to be a machine which it was impossible to +upset, but one which if left to itself would tend to right itself +from whatever direction a gust might come. When the principles +were extended to the 'B.E. 2c' type (largely used at the outbreak +of the War) the latter machine, if the engine were switched of f +at a height of not less than 1,000 feet above the ground, would +after a few moments assume its correct gliding angle and glide +down to the ground. + +The Paris Aero Salon of December, 1913, had been remarkable +chiefly for the large number of machines of which the chassis and +bodywork had been constructed of steel-tubing; for the excess of +monoplanes over biplanes; and (in the latter) predominance of +'pusher' machines (with propeller in rear of the main planes) +compared with the growing British preference for 'tractors' (with +air screw in front). Incidentally, the Maurice Farman, the last +relic of the old type box-kite with elevator in front appeared +shorn of this prefix, and became known as the 'short-horn' in +contradistinction to its front-elevatored predecessor which, +owing to its general reliability and easy flying capabilities, +had long been affectionately called the 'mechanical cow.' The +1913 Salon also saw some lingering attempts at attaining +automatic stability by pendulum and other freak devices. + +Apart from the appearance of 'R.E.1,' perhaps the most notable +development towards the end of 1913 was the appearance of the +Sopwith 'Tabloid 'tractor biplane. This single-seater machine, +evolved from the two-seater previously referred to, fitted with a +Gnome engine of 80 horse-power, had the, for those days, +remarkable speed of 92 miles an hour; while a still more +notable feature was that it could remain in level flight at not +more than 37 miles per hour. This machine is of particular +importance because it was the prototype and forerunner of the +successive designs of single-seater scout fighting machines +which were used so extensively from 1914 to 1918. It was also +probably the first machine to be capable of reaching a height of +1,000 feet within one minute. It was closely followed by the +'Bristol Bullet,' which was exhibited at the Olympia Aero Show +of March, 1914. This last pre-war show was mainly remarkable +for the good workmanship displayed--rather than for any distinct +advance in design. In fact, there was a notable diversity in +the types displayed, but in detailed design considerable +improvements were to be seen, such as the general adoption of +stranded steel cable in place of piano wire for the mail bracing + + + +IV. THE WAR PERIOD + +Up to this point an attempt has been made to give some idea of +the progress that was made during the eleven years that had +elapsed since the days of the Wrights' first flights. Much +advance had been made and aeroplanes had settled down, +superficially at any rate, into more or less standardised forms +in three main types--tractor monoplanes, tractor biplanes, and +pusher biplanes. Through the application of the results of +experiments with models in wind tunnels to full-scale machines, +considerable improvements had been made in the design of wing +sections, which had greatly increased the efficiency of +aeroplanes by raising the amount of 'lift' obtained from the +wing compared with the 'drag' (or resistance to forward motion) +which the same wing would cause. In the same way the shape of +bodies, interplane struts, etc., had been improved to be of +better stream-line shape, for the further reduction of +resistance; while the problems of stability were beginning to be +tolerably well understood. Records (for what they are worth) +stood at 21,000 feet as far as height was concerned, 126 miles +per hour for speed, and 24 hours duration. That there was +considerable room for development is, however, evidenced by a +statement made by the late B. C. Hucks (the famous pilot) in +the course of an address delivered before the Royal Aeronautical +Society in July, 1914. 'I consider,' he said, 'that the present +day standard of flying is due far more to the improvement in +piloting than to the improvement in machines.... I consider +those (early 1914) machines are only slight improvements on the +machines of three years ago, and yet they are put through +evolutions which, at that time, were not even dreamed of. I can +take a good example of the way improvement in piloting has +outdistanced improvement in machines--in the case of myself, my +'looping' Bleriot. Most of you know that there is very little +difference between that machine and the 50 horse-power Bleriot +of three years ago.' This statement was, of course, to some +extent an exaggeration and was by no means agreed with by +designers, but there was at the same time a germ of truth in it. +There is at any rate little doubt that the theory and practice +of aeroplane design made far greater strides towards becoming an +exact science during the four years of War than it had done +during the six or seven years preceding it. + +It is impossible in the space at disposal to treat of this +development even with the meagre amount of detail that has been +possible while covering the 'settling down' period from 1911 to +1914, and it is proposed, therefore, to indicate the improvements +by sketching briefly the more noticeable difference in various +respects between the average machine of 1914 and a similar +machine of 1918. + +In the first place, it was soon found that it was possible to +obtain greater efficiency and, in particular, higher speeds, +from tractor machines than from pusher machines with the air +screw behind the main planes. This was for a variety of reasons +connected with the efficiency of propellers and the possibility +of reducing resistance to a greater extent in tractor machines +by using a 'stream-line' fuselage (or body) to connect the main +planes with the tail. Full advantage of this could not be +taken, however, owing to the difficulty of fixing a machine-gun +in a forward direction owing to the presence of the propeller. +This was finally overcome by an ingenious device (known as an +'Interrupter gear') which allowed the gun to fire only when +none of the propeller blades was passing in front of the muzzle. +The monoplane gradually fell into desuetude, mainly owing to the +difficulty of making that type adequately strong without it +becoming prohibitively heavy, and also because of its high +landing speed and general lack of manoeuvrability. The triplane +was also little used except in one or two instances, and, +practically speaking, every machine was of the biplane tractor +type. + +A careful consideration of the salient features leading to +maximum efficiency in aeroplanes--particularly in regard to +speed and climb, which were the two most important military +requirements--showed that a vital feature was the reduction in +the amount of weight lifted per horse-power employed; which in +1914 averaged from 20 to 25 lbs. This was effected both by +gradual increase in the power and size of the engines used and +by great improvement in their detailed design (by increasing +compression ratio and saving weight whenever possible); with the +result that the motive power of single-seater aeroplanes rose +from 80 and 100 horse-power in 1914 to an average of 200 to 300 +horse-power, while the actual weight of the engine fell from 3 +1/2-4 lbs. per horse-power to an average of 2 1/2 lbs. per +horse-power. This meant that while a pre-war engine of 100 +horse-power would weigh some 400 lbs., the 1918 engine developing +three times the power would have less than double the weight. +The result of this improvement was that a scout aeroplane at the +time of the Armistice would have 1 horse-power for every 8 lbs. +of weight lifted, compared with the 20 or 25 lbs. of its 1914 +predecessors. This produced a considerable increase in the rate +of climb, a good postwar machine being able to reach 10,000 feet +in about 5 minutes and 20,000 feet in under half an hour. The +loading per square foot was also considerably increased; this +being rendered possible both by improvement in the design of wing +sections and by more scientific construction giving increased +strength. It will be remembered that in the machine of the very +early period each square foot of surface had only to lift a +weight of some 1 1/2 to 2 lbs., which by 1914 had been increased +to about 4 lbs. By 1918 aeroplanes habitually had a loading of 8 +lbs. or more per square foot of area; which resulted in great +increase in speed. Although a speed of 126 miles per hour had +been attained by a specially designed racing machine over a short +distance in 1914, the average at that period little exceeded, if +at all, 100 miles per hour; whereas in 1918 speeds of 130 miles +per hour had become a commonplace, and shortly afterwards a speed +of over 166 miles an hour was achieved. + +In another direction, also, that of size, great developments +were made. Before the War a few machines fitted with more than +one engine had been built (the first being a triple +Gnome-engined biplane built by Messrs Short Bros. at Eastchurch +in 1913), but none of large size had been successfully produced, +the total weight probably in no case exceeding about 2 tons. In +1916, however, the twin engine Handley-Page biplane was +produced, to be followed by others both in this country and +abroad, which represented a very great increase in size and, +consequently, load-carrying capacity. By the end of the War +period several types were in existence weighing a total of 10 +tons when fully loaded, of which some 4 tons or more represented +'useful load' available for crew, fuel, and bombs or passengers. +This was attained through very careful attention to detailed +design, which showed that the material could be employed more +efficiently as size increased, and was also due to the fact that +a large machine was not liable to be put through the same +evolutions as a small machine, and therefore could safely be +built with a lower factor of safety. Owing to the fact that a +wing section which is adopted for carrying heavy loads usually +has also a somewhat low lift to drag ratio, and is not therefore +productive of high speed, these machines are not as fast as +light scouts; but, nevertheless, they proved themselves capable +of achieving speeds of 100 miles an hour or more in some cases; +which was faster than the average small machine of 1914. + +In one respect the development during the War may perhaps have +proved to be somewhat disappointing, as it might have been +expected that great improvements would be effected in metal +construction, leading almost to the abolition of wooden +structures. Although, however, a good deal of experimental work +was done which resulted in overcoming at any rate the worst of +the difficulties, metal-built machines were little used (except +to a certain extent in Germany) chiefly on account of the need +for rapid production and the danger of delay resulting from +switching over from known and tried methods to experimental +types of construction. The Germans constructed some large +machines, such as the giant Siemens-Schukhert machine, entirely +of metal except for the wing covering, while the Fokker and +Junker firms about the time of the Armistice in 1918 both +produced monoplanes with very deep all-metal wings (including +the covering) which were entirely unstayed externally, depending +for their strength on internal bracing. In Great Britain cable +bracing gave place to a great extent to 'stream-line wires,' +which are steel rods rolled to a more or less oval section, +while tie-rods were also extensively used for the internal +bracing of the wings. Great developments in the economical use +of material were also made in the direction of using built-up +main spars for the wings and interplane struts; spars composed +of a series of layers (or 'laminations') of different pieces of +wood also being used. + +Apart from the metallic construction of aeroplanes an enormous +amount of work was done in the testing of different steels and +light alloys for use in engines, and by the end of the War +period a number of aircraft engines were in use of which the +pistons and other parts were of such alloys; the chief +difficulty having been not so much in the design as in the +successful heat-treatment and casting of the metal. + +An important development in connection with the inspection and +testing of aircraft parts, particularly in the case of metal, +was the experimental application of X-ray photography, which +showed up latent defects, both in the material and in +manufacture, which would otherwise have passed unnoticed. This +method was also used to test the penetration of glue into the +wood on each side of joints, so giving a measure of the +strength; and for the effect of 'doping' the wings, dope being a +film (of cellulose acetate dissolved in acetone with other +chemicals) applied to the covering of wings and bodies to render +the linen taut and weatherproof, besides giving it a smooth +surface for the lessening of 'skin friction' when passing rapidly +through the air. + +An important result of this experimental work was that it in +many cases enabled designers to produce aeroplane parts from +less costly material than had previously been considered +necessary, without impairing the strength. It may be mentioned +that it was found undesirable to use welded joints on aircraft +in any part where the material is subjectto a tensile or bending +load, owing to the danger resulting from bad workmanship causing +the material to become brittle--an effect which cannot be +discovered except by cutting through the weld, which, of course, +involves a test to destruction. Written, as it has been, in +August, 1920, it is impossible in this chapter to give any +conception of how the developments of War will be applied to +commercial aeroplanes, as few truly commercial machines have yet +been designed, and even those still show distinct traces of the +survival of war mentality. When, however, the inevitable +recasting of ideas arrives, it will become evident, whatever the +apparent modification in the relative importance of different +aspects of design, that enormous advances were made under the +impetus of War which have left an indelible mark on progress. + +We have, during the seventeen years since aeroplanes first took +the air, seen them grow from tentative experimental structures +of unknown and unknowable performance to highly scientific +products, of which not only the performances (in speed, +load-carrying capacity, and climb) are known, but of which the +precise strength and degree of stability can be forecast with +some accuracy on the drawing board. For the rest, with the +future lies--apart from some revolutionary change in fundamental +design--the steady development of a now well-tried and well-found +engineering structure. + + + +PART III + +AEROSTATICS + +I. BEGINNINGS + +Francesco Lana, with his 'aerial ship,' stands as one of the +first great exponents of aerostatics; up to the time of the +Montgolfier and Charles balloon experiments, aerostatic and +aerodynamic research are so inextricably intermingled that it +has been thought well to treat of them as one, and thus the work +of Lana, Veranzio and his parachute, Guzman's frauds, and the +like, have already been sketched. In connection with Guzman, +Hildebrandt states in his Airships Past and Present, a fairly +exhaustive treatise on the subject up to 1906, the year of its +publication, that there were two inventors--or +charlatans--Lorenzo de Guzman and a monk Bartolemeo Laurenzo, +the former of whom constructed an unsuccessful airship out of a +wooden basket covered with paper, while the latter made certain +experiments with a machine of which no description remains. A +third de Guzman, some twenty-five years later, announced that he +had constructed a flying machine, with which he proposed to fly +from a tower to prove his success to the public. The lack of +record of any fatal accident overtaking him about that time +seems to show that the experiment was not carried out. + +Galien, a French monk, published a book L'art de naviguer dans +l'air in 1757, in which it was conjectured that the air at high +levels was lighter than that immediately over the surface of +the earth. Galien proposed to bring down the upper layers of +air and with them fill a vessel, which by Archimidean principle +would rise through the heavier atmosphere. If one went high +enough, said Galien, the air would be two thousand times as +light as water, and it would be possible to construct an +airship, with this light air as lifting factor, which should be +as large as the town of Avignon, and carry four million +passengers with their baggage. How this high air was to be +obtained is matter for conjecture--Galien seems to have thought +in a vicious circle, in which the vessel that must rise to +obtain the light air must first be filled with it in order to +rise. + +Cavendish's discovery of hydrogen in 1776 set men thinking, and +soon a certain Doctor Black was suggesting that vessels might be +filled with hydrogen, in order that they might rise in the air. +Black, however, did not get beyond suggestion; it was Leo +Cavallo who first made experiments with hydrogen, beginning with +filling soap bubbles, and passing on to bladders and special +paper bags. In these latter the gas escaped, and Cavallo was +about to try goldbeaters' skin at the time that the Montgolfiers +came into the field with their hot air balloon. + +Joseph and Stephen Montgolfier, sons of a wealthy French paper +manufacturer, carried out many experiments in physics, and +Joseph interested himself in the study of aeronautics some time +before the first balloon was constructed by the brothers--he is +said to have made a parachute descent from the roof of his house +as early as 1771, but of this there is no proof. Galien's idea, +together with study of the movement of clouds, gave Joseph some +hope of achieving aerostation through Galien's schemes, and the +first experiments were made by passing steam into a receiver, +which, of course, tended to rise--but the rapid condensation of +the steam prevented the receiver from more than threatening +ascent. The experiments were continued with smoke, which +produced only a slightly better effect, and, moreover, the paper +bag into which the smoke was induced permitted of escape through +its pores; finding this method a failure the brothers desisted +until Priestley's work became known to them, and they conceived +the use of hydrogen as a lifting factor. Trying this with paper +bags, they found that the hydrogen escaped through the pores of +the paper. + +Their first balloon, made of paper, reverted to the hot-air +principle; they lighted a fire of wool and wet straw under the +balloon--and as a matter of course the balloon took fire after +very little experiment; thereupon they constructed a second, +having a capacity of 700 cubic feet, and this rose to a height +of over 1,000 feet. Such a success gave them confidence, and +they gave their first public exhibition on June 5th, 1783, with +a balloon constructed of paper and of a circumference of 112 +feet. A fire was lighted under this balloon, which, after +rising to a height of 1,000 feet, descended through the cooling +of the air inside a matter of ten minutes. At this the Academie +des Sciences invited the brothers to conduct experiments in +Paris. + +The Montgolfiers were undoubtedly first to send up balloons, but +other experimenters were not far behind them, and before they +could get to Paris in response to their invitation, Charles, a +prominent physicist of those days, had constructed a balloon of +silk, which he proofed against escape of gas with rubber--the +Roberts had just succeeded in dissolving this substance to +permit of making a suitable coating for the silk. With a +quarter of a ton of sulphuric acid, and half a ton of iron +filings and turnings, sufficient hydrogen was generated in four +days to fill Charles's balloon, which went up on August 28th, +1783. Although the day was wet, Paris turned out to the number +of over 300,000 in the Champs de Mars, and cannon were fired to +announce the ascent of the balloon. This, rising very rapidly, +disappeared amid the rain clouds, but, probably bursting through +no outlet being provided to compensate for the escape of gas, +fell soon in the neighbourhood of Paris. Here peasants, +ascribing evil supernatural influence to the fall of such a +thing from nowhere, went at it with the implements of their +craft--forks, hoes, and the like--and maltreated it severely, +finally attaching it to a horse's tail and dragging it about +until it was mere rag and scrap. + +Meanwhile, Joseph Montgolfier, having come to Paris, set about +the construction of a balloon out of linen; this was in three +diverse sections, the top being a cone 30 feet in depth, the +middle a cylinder 42 feet in diameter by 26 feet in depth, and +the bottom another cone 20 feet in depth from junction with the +cylindrical portion to its point. The balloon was both lined +and covered with paper, decorated in blue and gold. Before ever +an ascent could be attempted this ambitious balloon was caught +in a heavy rainstorm which reduced its paper covering to pulp +and tore the linen at its seams, so that a supervening strong +wind tore the whole thing to shreds. + +Montgolfier's next balloon was spherical, having a capacity of +52,000 cubic feet. It was made from waterproofed linen, and on +September 19th, 1783, it made an ascent for the palace courtyard +at Versailles, taking up as passengers a cock, a sheep, and a +duck. A rent at the top of the balloon caused it to descend +within eight minutes, and the duck and sheep were found none the +worse for being the first living things to leave the earth in a +balloon, but the cock, evidently suffering, was thought to have +been affected by the rarefaction of the atmosphere at the +tremendous height reached--for at that time the general opinion +was that the atmosphere did not extend more than four or five +miles above the earth's surface. It transpired later that the +sheep had trampled on the cock, causing more solid injury than +any that might be inflicted by rarefied air in an eight-minute +ascent and descent of a balloon. + +For achieving this flight Joseph Montgolfier received from the +King of France a pension of of L40, while Stephen was given +the order of St Michael, and a patent of nobility was granted to +their father. They were made members of the Legion d'Honneur, +and a scientific deputation, of which Faujas de Saint-Fond, who +had raised the funds with which Charles's hydrogen balloon was +constructed, presented to Stephen Montgolfier a gold medal +struck in honour of his aerial conquest. Since Joseph appears +to have had quite as much share in the success as Stephen, the +presentation of the medal to one brother only was in +questionable taste, unless it was intended to balance Joseph's +pension. + +Once aerostation had been proved possible, many people began the +construction of small balloons--the wholehole thing was regarded +as a matter of spectacles and a form of amusement by the great +majority. A certain Baron de Beaumanoir made the first balloon +of goldbeaters' skin, this being eighteen inches in diameter, and +using hydrogen as a lifting factor. Few people saw any +possibilities in aerostation, in spite of the adventures of the +duck and sheep and cock; voyages to the moon were talked and +written, and there was more of levity than seriousness over +ballooning as a rule. The classic retort of Benjamin Franklin +stands as an exception to the general rule: asked what was the +use of ballooning--'What's the use of a baby?' he countered, and +the spirit of that reply brought both the dirigible and the +aeroplane to being, later. + +The next noteworthy balloon was one by Stephen Montgolfier, +designed to take up passengers, and therefore of rather large +dimensions, as these things went then. The capacity was 100,000 +cubic feet, the depth being 85 feet, and the exterior was very +gaily decorated. A short, cylindrical opening was made at the +lower extremity, and under this a fire-pan was suspended, above +the passenger car of the balloon. On October 15th, 1783, +Pilatre de Rozier made the first balloon ascent--but the balloon +was held captive, and only allowed to rise to a height of 80 +feet. But, a little later in 1783, Rozier secured the honour +of making the first ascent in a free balloon, taking up with him +the Marquis d'Arlandes. It had been originally intended that +two criminals, condemned to death, should risk their lives in +the perilous venture, with the prospect of a free pardon if they +made a safe descent, but d'Arlandes got the royal consent to +accompany Rozier, and the criminals lost their chance. Rozier +and d'Arlandes made a voyage lasting for twenty-five minutes, +and, on landing, the balloon collapsed with such rapidity as +almost to suffocate Rozier, who, however, was dragged out to +safety by d'Arlandes. This first aerostatic journey took place +on November 21st, 1783. + +Some seven months later, on June 4th, 1784, a Madame Thible +ascended in a free balloon, reaching a height of 9,000 feet, and +making a journey which lasted for forty-five minutes--the great +King Gustavus of Sweden witnessed this ascent. France grew used +to balloon ascents in the course of a few months, in spite of +the brewing of such a storm as might have been calculated to +wipe out all but purely political interests. Meanwhile, +interest in the new discovery spread across the Channel, and on +September 15th, 1784, one Vincent Lunardi made the first balloon +voyage in England, starting from the Artillery Ground at +Chelsea, with a cat and dog as passengers, and landing in a +field in the parish of Standon, near Ware. There is a rather +rare book which gives a very detailed account of this first +ascent in England, one copy of which is in the library of the +Royal Aeronautical Society; the venturesome Lunardi won a +greater measure of fame through his exploit than did Cody for +his infinitely more courageous and--from a scientific point of +view--valuable first aeroplane ascent in this country. + +The Montgolfier type of balloon, depending on hot air for its +lifting power, was soon realised as having dangerous +limitations. There was always a possibility of the balloon +catching fire while it was being filled, and on landing there +was further danger from the hot pan which kept up the supply of +hot air on the voyage --the collapsing balloon fell on the pan, +inevitably. The scientist Saussure, observing the filling of +the balloons very carefully, ascertained that it was rarefaction +of the air which was responsible for the lifting power, and not +the heat in itself, and, owing to the rarefaction of the air at +normal temperature at great heights above the earth, the limit +of ascent for a balloon of the Montgolfier type was estimated by +him at under 9,000 feet. Moreover, since the amount of fuel +that could be carried for maintaining the heat of the balloon +after inflation was subject to definite limits, prescribed by +the carrying capacity of the balloon, the duration of the +journey was necessarily limited just as strictly. + +These considerations tended to turn the minds of those +interested in aerostation to consideration of the hydrogen +balloon evolved by Professor Charles. Certain improvements had +been made by Charles since his first construction; he employed +rubber-coated silk in the construction of a balloon of 30 feet +diameter, and provided a net for distributing the pressure +uniformly over the surface of the envelope; this net covered the +top half of the balloon, and from its lower edge dependent ropes +hung to join on a wooden ring, from which the car of the balloon +was suspended--apart from the extension of the net so as to +cover in the whole of the envelope, the spherical balloon of +to-day is virtually identical with that of Charles in its method +of construction. He introduced the valve at the top of the +balloon, by which escape of gas could be controlled, operating +his valve by means of ropes which depended to the car of the +balloon, and he also inserted a tube, of about 7 inches +diameter, at the bottom of the balloon, not only for purposes of +inflation, but also to provide a means of escape for gas in case +of expansion due to atmospheric conditions. + +Sulphuric acid and iron filings were used by Charles for filling +his balloon, which required three days and three nights for the +generation of its 14,000 cubic feet of hydrogen gas. The +inflation was completed on December 1st, 1783, and the fittings +carried included a barometer and a grapnel form of anchor. In +addition to this, Charles provided the first 'ballon sonde' in +the form of a small pilot balloon which he handed to Montgolfier +to launch before his own ascent, in order to determine the +direction and velocity of the wind. It was a graceful compliment +to his rival, and indicated that, although they were both working +to the one end, their rivalry was not a matter of bitterness. + +Ascending on December 1st, 1783, Charles took with him one of +the brothers Robert, and with him made the record journey up to +that date, covering a period of three and three-quarter hours, +in which time they journeyed some forty miles. Robert then +landed, and Charles ascended again alone, reaching such a height +as to feel the effects of the rarefaction of the air, this very +largely due to the rapidity of his ascent. Opening the valve at +the top of the balloon, he descended thirty-five minutes after +leaving Robert behind, and came to earth a few miles from the +point of the first descent. His discomfort over the rapid +ascent was mainly due to the fact that, when Robert landed, he +forgot to compensate for the reduction of weight by taking in +further ballast, but the ascent proved the value of the tube at +the bottom of the balloon envelope, for the gas escaped very +rapidly in that second ascent, and, but for the tube, the +balloon must inevitably have burst in the air, with fatal +results for Charles. + +As in the case of aeroplane flight, as soon as the balloon was +proved practicable the flight across the English Channel was +talked of, and Rozier, who had the honour of the first flight, +announced his intention of being first to cross. But Blanchard, +who had an idea for a 'flying car,' anticipated him, and made a +start from Dover on January 7th, 1785, taking with him an +American doctor named Jeffries. Blanchard fitted out his craft +for the journey very thoroughly, taking provisions, oars, and +even wings, for propulsion in case of need. He took so much, in +fact, that as soon as the balloon lifted clear of the ground the +whole of the ballast had to be jettisoned, lest the balloon +should drop into the sea. Half-way across the Channel the +sinking of the balloon warned Blanchard that he had to part with +more than ballast to accomplish the journey, and all the +equipment went, together with certain books and papers that were +on board the car. The balloon looked perilously like +collapsing, and both Blanchard and Jeffries began to undress in +order further to lighten their craft--Jeffries even proposed a +heroic dive to save the situation, but suddenly the balloon rose +sufficiently to clear the French coast, and the two voyagers +landed at a point near Calais in the Forest of Gaines, where a +marble column was subsequently erected to commemorate the great +feat. + +Rozier, although not first across, determined to be second, and +for that purpose he constructed a balloon which was to owe its +buoyancy to a combination of the hydrogen and hot air +principles. There was a spherical hydrogen balloon above, and +beneath it a cylindrical container which could be filled with +hot air, thus compensating for the leakage of gas from the +hydrogen portion of the balloon--regulating the heat of his +fire, he thought, would give him perfect control in the matter of +ascending and descending. + +On July 6th, 1785, a favourable breeze gave Rozier his +opportunity of starting from the French coast, and with a +passenger aboard he cast off in his balloon, which he had named +the 'Aero-Montgolfiere.' There was a rapid rise at first, and +then for a time the balloon remained stationary over the land, +after which a cloud suddenly appeared round the balloon, +denoting that an explosion had taken place. Both Rozier and his +companion were killed in the fall, so that he, first to leave +the earth by balloon, was also first victim to the art of +aerostation. + +There followed, naturally, a lull in the enthusiasm with which +ballooning had been taken up, so far as France was concerned. +In Italy, however, Count Zambeccari took up hot-air ballooning, +using a spirit lamp to give him buoyancy, and on the first +occasion when the balloon car was set on fire Zambeccari let +down his passenger by means of the anchor rope, and managed to +extinguish the fire while in the air. This reduced the buoyancy +of the balloon to such an extent that it fell into the Adriatic +and was totally wrecked, Zambeccari being rescued by fishermen. +He continued to experiment up to 1812, when he attempted to +ascend at Bologna; the spirit in his lamp was upset by the +collision of the car with a tree, and the car was again set on +fire. Zambeccari jumped from the car when it was over fifty feet +above level ground, and was killed. With him the Rozier type of +balloon, combining the hydrogen and hot air principles, +disappeared; the combination was obviously too dangerous to be +practical. + +The brothers Robert were first to note how the heat of the sun +acted on the gases within a balloon envelope, and it has since +been ascertained that sun rays will heat the gas in a balloon to +as much as 80 degrees Fahrenheit greater temperature than the +surrounding atmosphere; hydrogen, being less affected by change +of temperature than coal gas, is the most suitable filling +element, and coal gas comes next as the medium of buoyancy. This +for the free and non-navigable balloon, though for the airship, +carrying means of combustion, and in military work liable to +ignition by explosives, the gas helium seems likely to replace +hydrogen, being non-combustible. + +In spite of the development of the dirigible airship, there +remains work for the free, spherical type of balloon in the +scientific field. Blanchard's companion on the first Channel +crossing by balloon, Dr Jeffries, was the first balloonist to +ascend for purely scientific purposes; as early as 1784 he made +an ascent to a height of 9,000 feet, and observed a fall in +temperature of from degrees--at the level of London, where he +began his ascent--to 29 degrees at the maximum height reached. +He took up an electrometer, a hydrometer, a compass, a +thermometer, and a Toricelli barometer, together with bottles of +water, in order to collect samples of the air at different +heights. In 1785 he made a second ascent, when trigonometrical +observations of the height of the balloon were made from the +French coast, giving an altitude of 4,800 feet. + +The matter was taken up on its scientific side very early in +America, experiments in Philadelphia being almost simultaneous +with those of the Montgolfiers in France. The flight of Rozier +and d'Arlandes inspired two members of the Philadelphia +Philosophical Academy to construct a balloon or series of +balloons of their own design; they made a machine which consisted +of no less than 47 small hydrogen balloons attached to a wicker +car, and made certain preliminary trials, using animals as +passengers. This was followed by a captive ascent with a man as +passenger, and eventually by the first free ascent in America, +which was undertaken by one James Wilcox, a carpenter, on +December 28th, 1783. Wilcox, fearful of falling into a river, +attempted to regulate his landing by cutting slits in some of the +supporting balloons, which was the method adopted for regulating +ascent or descent in this machine. He first cut three, and then, +finding that the effect produced was not sufficient, cut three +more, and then another five--eleven out of the forty-seven. The +result was so swift a descent that he dislocated his wrist on +landing. + + A NOTE ON BALLONETS OR AIR BAGS. + +Meusnier, toward the end of the eighteenth century, was first to +conceive the idea of compensating for the loss of gas due to +expansion by fitting to the interior of a free balloon a +ballonet, or air bag, which could be pumped full of air so as to +retain the shape and rigidity of the envelope. + +The ballonet became particularly valuable as soon as airship +construction became general, and it was in the course of advance +in Astra Torres design that the project was introduced of using +the ballonets in order to give inclination from the horizontal. +In the earlier Astra Torres, trimming was accomplished by moving +the car fore and aft--this in itself was an advance on the +separate 'sliding weigh' principle--and this was the method +followed in the Astra Torres bought by the British Government +from France in 1912 for training airship pilots. Subsequently, +the two ballonets fitted inside the envelope were made to serve +for trimming by the extent of their inflation, and this method of +securing inclination proved the best until exterior rudders, and +greater engine power, supplanted it, as in the Zeppelin and, in +fact, all rigid types. + +In the kite balloon, the ballonet serves the purpose of a +rudder, filling itself through the opening being kept pointed +toward the wind--there is an ingenious type of air scoop with +non-return valve which assures perfect inflation. In the S.S. +type of airship, two ballonets are provided, the supply of air +being taken from the propeller draught by a slanting aluminium +tube to the underside of the envelope, where it meets a +longitudinal fabric hose which connects the two ballonet air +inlets. In this hose the non-return air valves, known as +'crab-pots,' are fitted, on either side of the junction with the +air-scoop. Two automatic air valves, one for each ballonet, are +fitted in the underside of the envelope, and, as the air +pressure tends to open these instead of keeping them shut, the +spring of the valve is set inside the envelope. Each spring is +set to open at a pressure of 25 to 28 mm. + + + +II. THE FIRST DIRIGIBLES + +Having got off the earth, the very early balloonists set about +the task of finding a means of navigating the air but, lacking +steam or other accessory power to human muscle, they failed to +solve the problem. Joseph Montgolfier speedily exploded the +idea of propelling a balloon either by means of oars or sails, +pointing out that even in a dead calm a speed of five miles an +hour would be the limit achieved. Still, sailing balloons were +constructed, even up to the time of Andree, the explorer, who +proposed to retard the speed of the balloon by ropes dragging on +the ground, and then to spread a sail which should catch the +wind and permit of deviation of the course. It has been proved +that slight divergences from the course of the wind can be +obtained by this means, but no real navigation of the air could +be thus accomplished. + +Professor Wellner, of Brunn, brought up the idea of a sailing +balloon in more practical fashion in 1883. He observed that +surfaces inclined to the horizontal have a slight lateral motion +in rising and falling, and deduced that by alternate lowering +and raising of such surfaces he would be able to navigate the +air, regulating ascent and descent by increasing or decreasing +the temperature of his buoyant medium in the balloon. He +calculated that a balloon, 50 feet in diameter and 150 feet in +length, with a vertical surface in front and a horizontal +surface behind, might be navigated at a speed of ten miles per +hour, and in actual tests at Brunn he proved that a single rise +and fall moved the balloon three miles against the wind. His +ideas were further developed by Lebaudy in the construction of +the early French dirigibles. + +According to Hildebrandt,[*] the first sailing balloon was built +in 1784 by Guyot, who made his balloon egg-shaped, with the +smaller end at the back and the longer axis horizontal; oars +were intended to propel the craft, and naturally it was a +failure. Carra proposed the use of paddle wheels, a step in the +right direction, by mounting them on the sides of the car, but +the improvement was only slight. Guyton de Morveau, entrusted +by the Academy of Dijon with the building of a sailing balloon, +first used a vertical rudder at the rear end of his +construction--it survives in the modern dirigible. His +construction included sails and oars, but, lacking steam or +other than human propulsive power, the airship was a failure +equally with Guyot's. + +[*] Airships Past and Present. + +Two priests, Miollan and Janinet, proposed to drive balloons +through the air by the forcible expulsion of the hot air in the +envelope from the rear of the balloon. An opening was made +about half-way up the envelope, through which the hot air was to +escape, buoyancy being maintained by a pan of combustibles in +the car. Unfortunately, this development of the Montgolfier type +never got a trial, for those who were to be spectators of the +first flight grew exasperated at successive delays, and in the +end, thinking that the balloon would never rise, they destroyed +it. + +Meusnier, a French general, first conceived the idea of +compensating for loss of gas by carrying an air bag inside the +balloon, in order to maintain the full expansion of the +envelope. The brothers Robert constructed the first balloon in +which this was tried and placed the air bag near the neck of the +balloon which was intended to be driven by oars, and steered by +a rudder. A violent swirl of wind which was encountered on the +first ascent tore away the oars and rudder and broke the ropes +which held the air bag in position; the bag fell into the +opening of the neck and stopped it up, preventing the escape of +gas under expansion. The Duc de Chartres, who was aboard, +realised the extreme danger of the envelope bursting as the +balloon ascended, and at 16,000 feet he thrust a staff through +the envelope--another account says that he slit it with his +sword--and thus prevented disaster. The descent after this rip +in the fabric was swift, but the passengers got off without +injury in the landing. + +Meusnier, experimenting in various ways, experimented with +regard to the resistance offered by various shapes to the air, +and found that an elliptical shape was best; he proposed to make +the car boat--shaped, in order further to decrease the +resistance, and he advocated an entirely rigid connection +between the car and the body of the balloon, as indispensable to +a dirigible.[*] He suggested using three propellers, which were +to be driven by hand by means of pulleys, and calculated that a +crew of eighty would be required to furnish sufficient motive +power. Horizontal fins were to be used to assure stability, and +Meusnier thoroughly investigated the pressures exerted by gases, +in order to ascertain the stresses to which the envelope would be +subjected. More important still, he went into detail with +regard to the use of air bags, in order to retain the shape of +the balloon under varying pressures of gas due to expansion and +consequent losses; he proposed two separate envelopes, the inner +one containing gas, and the space between it and the outer one +being filled with air. Further, by compressing the air inside +the air bag, the rate of ascent or descent could be regulated. +Lebaudy, acting on this principle, found it possible to pump air +at the rate of 35 cubic feet per second, thus making good loss +of ballast which had to be thrown overboard. + +[*] Hildebrandt. + +Meusnier's balloon, of course, was never constructed, but his +ideas have been of value to aerostation up to the present time. +His career ended in the revolutionary army in 1793, when he was +killed in the fighting before Mayence, and the King of Prussia +ordered all firing to cease until Meusnier had been buried. No +other genius came forward to carry on his work, and it was +realised that human muscle could not drive a balloon with +certainty through the air; experiment in this direction was +abandoned for nearly sixty years, until in 1852 Giffard +brought the first practicable power-driven dirigible to being. + +Giffard, inventor of the steam injector, had already made +balloon ascents when he turned to aeronautical propulsion, and +constructed a steam engine of 5 horsepower with a weight of only +100 lbs.--a great achievement for his day. Having got his +engine, he set about making the balloon which it was to drive; +this he built with the aid of two other enthusiasts, diverging +from Meusnier's ideas by making the ends pointed, and keeping the +body narrowed from Meusnier's ellipse to a shape more resembling +a rather fat cigar. The length was 144 feet, and the greatest +diameter only 40 feet, while the capacity was 88,000 cubic feet. +A net which covered the envelope of the balloon supported a +spar, 66 feet in length, at the end of which a triangular sail +was placed vertically to act as rudder. The car, slung 20 feet +below the spar, carried the engine and propeller. Engine and +boiler together weighed 350 lbs., and drove the 11 foot +propeller at 110 revolutions per minute. + +As precaution against explosion, Giffard arranged wire gauze in +front of the stoke-hole of his boiler, and provided an exhaust +pipe which discharged the waste gases from the engine in a +downward direction. With this first dirigible he attained to a +speed of between 6 and 8 feet per second, thus proving that the +propulsion of a balloon was a possibility, now that steam had +come to supplement human effort. + +Three years later he built a second dirigible, reducing the +diameter and increasing the length of the gas envelope, with a +view to reducing air resistance. The length of this was 230 +feet, the diameter only 33 feet, and the capacity was 113,000 +cubic feet, while the upper part of the envelope, to which the +covering net was attached, was specially covered to ensure a +stiffening effect. The car of this dirigible was dropped rather +lower than that of the first machine, in order to provide more +thoroughly against the danger of explosions. Giffard, with a +companion named Yon as passenger, took a trial trip on this +vessel, and made a journey against the wind, though slowly. In +commencing to descend, the nose of the envelope tilted upwards, +and the weight of the car and its contents caused the net to +slip, so that just before the dirigible reached the ground, the +envelope burst. Both Giffard and his companion escaped with very +slight injuries. + +Plans were immediately made for the construction of a third +dirigible, which was to be 1,970 feet in length, 98 feet in +extreme diameter, and to have a capacity of 7,800,000 cubic feet +of gas. The engine of this giant was to have weighed 30 tons, +and with it Giffard expected to attain a speed of 40 miles per +hour. Cost prevented the scheme being carried out, and Giffard +went on designing small steam engines until his invention of the +steam injector gave him the funds to turn to dirigibles again. +He built a captive balloon for the great exhibition in London in +1868, at a cost of nearly L30,000, and designed a dirigible +balloon which was to have held a million and three quarters +cubic feet of gas, carry two boilers, and cost about L40,000. +The plans were thoroughly worked out, down to the last detail, +but the dirigible was never constructed. Giffard went blind, and +died in 1882--he stands as the great pioneer of dirigible +construction, more on the strength of the two vessels which he +actually built than on that of the ambitious later conceptions +of his brain. + +In 1872 Dupuy de Lome, commissioned by the French government, +built a dirigible which he proposed to drive by man-power--it +was anticipated that the vessel would be of use in the siege of +Paris, but it was not actually tested till after the conclusion +of the war. The length of this vessel was 118 feet, its +greatest diameter 49 feet, the ends being pointed, and the +motive power was by a propeller which was revolved by the +efforts of eight men. The vessel attained to about the same +speed as Giffard's steam-driven airship; it was capable of +carrying fourteen men, who, apart from these engaged in driving +the propeller, had to manipulate the pumps which controlled the +air bags inside the gas envelope. + +In the same year Paul Haenlein, working in Vienna, produced an +airship which was a direct forerunner of the Lebaudy type, 164 +feet in length, 30 feet greatest diameter, and with a cubic +capacity of 85,000 feet. Semi-rigidity was attained by placing +the car as close to the envelope as possible, suspending it by +crossed ropes, and the motive power was a gas engine of the +Lenoir type, having four horizontal cylinders, and giving about +5 horse-power with a consumption of about 250 cubic feet of gas +per hour. This gas was sucked from the envelope of the balloon, +which was kept fully inflated by pumping in compensating air to +the air bags inside the main envelope. A propeller, 15 feet in +diameter, was driven by the Lenoir engine at 40 revolutions per +minute. This was the first instance of the use of an internal +combustion engine in connection with aeronautical experiments. + +The envelope of this dirigible was rendered airtight by means of +internal rubber coating, with a thinner film on the outside. +Coal gas, used for inflation, formed a suitable fuel for the +engine, but limited the height to which the dirigible could +ascend. Such trials as were made were carried out with the +dirigible held captive, and a speed of I 5 feet per second was +attained. Full experiment was prevented through funds running +low, but Haenlein's work constituted a distinct advance on all +that had been done previously. + +Two brothers, Albert and Gaston Tissandier, were next to enter +the field of dirigible construction; they had experimented with +balloons during the Franc-Prussian War, and had attempted to get +into Paris by balloon during the siege, but it was not until +1882 that they produced their dirigible. + +This was 92 feet in length and 32 feet in greatest diameter, +with a cubic capacity of 37,500 feet, and the fabric used was +varnished cambric. The car was made of bamboo rods, and in +addition to its crew of three, it carried a Siemens dynamo, with +24 bichromate cells, each of which weighed 17 lbs. The motor +gave out 1 1/2 horse-power, which was sufficient to drive the +vessel at a speed of up to 10 feet per second. This was not so +good as Haenlein's previous attempt and, after L2,000 had been +spent, the Tissandier abandoned their experiments, since a 5-mile +breeze was sufficient to nullify the power of the motor. + +Renard, a French officer who had studied the problem of +dirigible construction since 1878, associated himself first with +a brother officer named La Haye, and subsequently with another +officer, Krebs, in the construction of the second dirigible to +be electrically-propelled. La Haye first approached Colonel +Laussedat, in charge of the Engineers of the French Army, with a +view to obtaining funds, but was refused, in consequence of the +practical failure of all experiments since 1870. Renard, with +whom Krebs had now associated himself, thereupon went to +Gambetta, and succeeded in getting a promise of a grant of +L8,000 for the work; with this promise Renard and Krebs set to +work. + +They built their airship in torpedo shape, 165 feet in length, +and of just over 27 feet greatest diameter--the greatest diameter +was at the front, and the cubic capacity was 66,000 feet. The +car itself was 108 feet in length, and 4 1/2 feet broad, covered +with silk over the bamboo framework. The 23 foot diameter +propeller was of wood, and was driven by an electric motor +connected to an accumulator, and yielding 8.5 horsepower. The +sweep of the propeller, which might have brought it in contact +with the ground in landing, was counteracted by rendering it +possible to raise the axis on which the blades were mounted, and +a guide rope was used to obviate damage altogether, in case of +rapid descent. There was also a 'sliding weight' which was +movable to any required position to shift the centre of gravity +as desired. Altogether, with passengers and ballast aboard, the +craft weighed two tons. + +In the afternoon of August 8th, 1884, Renard and Krebs ascended +in the dirigible--which they had named 'La France,' from the +military ballooning ground at Chalais-Meudon, making a circular +flight of about five miles, the latter part of which was in the +face of a slight wind. They found that the vessel answered well +to her rudder, and the five-mile flight was made successfully in +a period of 23 minutes. Subsequent experimental flights +determined that the air speed of the dirigible was no less than +14 1/2 miles per hour, by far the best that had so far been +accomplished in dirigible flight. Seven flights in all were +made, and of these five were completely successful, the +dirigible returning to its starting point with no difficulty. On +the other two flights it had to be towed back. + +Renard attempted to repeat his construction on a larger scale, +but funds would not permit, and the type was abandoned; the +motive power was not sufficient to permit of more than short +flights, and even to the present time electric motors, with +their necessary accumulators, are far too cumbrous to compete +with the self-contained internal combustion engine. France had +to wait for the Lebaudy brothers, just as Germany had to wait +for Zeppelin and Parseval. + +Two German experimenters, Baumgarten and Wolfert, fitted a +Daimler motor to a dirigible balloon which made its first ascent +at Leipzig in 1880. This vessel had three cars, and placing a +passenger in one of the outer cars[*] distributed the load +unevenly, so that the whole vessel tilted over and crashed to +the earth, the occupants luckily escaping without injury. After +Baumgarten's death, Wolfert determined to carry on with his +experiments, and, having achieved a certain measure of success, +he announced an ascent to take place on the Tempelhofer Field, +near Berlin, on June 12th, 1897. The vessel, travelling with +the wind, reached a height of 600 feet, when the exhaust of the +motor communicated flame to the envelope of the balloon, and +Wolfert, together with a passenger he carried, was either killed +by the fall or burnt to death on the ground. Giffard had taken +special precautions to avoid an accident of this nature, and +Wolfert, failing to observe equal care, paid the full penalty. + +[*] Hildebrandt. + +Platz, a German soldier, attempting an ascent on the Tempelhofer +Field in the Schwartz airship in 1897, merely proved the +dirigible a failure. The vessel was of aluminium, 0.008 inch +in thickness, strengthened by an aluminium lattice work; the +motor was two-cylindered petrol-driven; at the first trial the +metal developed such leaks that the vessel came to the ground +within four miles of its starting point. Platz, who was aboard +alone as crew, succeeded in escaping by jumping clear before the +car touched earth, but the shock of alighting broke up the +balloon, and a following high wind completed the work of full +destruction. A second account says that Platz, finding the +propellers insufficient to drive the vessel against the wind, +opened the valve and descended too rapidly. + +The envelope of this dirigible was 156 feet in length, and the +method of filling was that of pushing in bags, fill them with +gas, and then pulling them to pieces and tearing them out of the +body of the balloon. A second contemplated method of filling +was by placing a linen envelope inside the aluminium casing, +blowing it out with air, and then admitting the gas between the +linen and the aluminium outer casing. This would compress the +air out of the linen envelope, which was to be withdrawn when +the aluminium casing had been completely filled with gas. + +All this, however, assumes that the Schwartz type--the first +rigid dirigible, by the way--would prove successful. As it +proved a failure on the first trial, the problem of filling it +did not arise again. + +By this time Zeppelin, retired from the German army, had begun +to devote himself to the study of dirigible construction, and, a +year after Schwartz had made his experiment and had failed, he +got together sufficient funds for the formation of a +limitedliability company, and started on the construction of the +first of his series of airships. The age of tentative +experiment was over, and, forerunner of the success of the +heavier-than-air type of flying machine, successful dirigible +flight was accomplished by Zeppelin in Germany, and by +Santos-Dumont in France. + + + +III. SANTOS-DUMONT + +A Brazilian by birth, Santos-Dumont began in Paris in the year +1898 to make history, which he subsequently wrote. His book, My +Airships, is a record of his eight years of work on +lighter-than-air machines, a period in which he constructed no +less than fourteen dirigible balloons, beginning with a cubic +capacity of 6,350 feet, and an engine of 3 horse-power, and +rising to a cubic capacity of 71,000 feet on the tenth dirigible +he constructed, and an engine of 60 horse-power, which was +fitted to the seventh machine in order of construction, the one +which he built after winning the Deutsch Prize. + +The student of dirigible construction is recommended to +Santos-Dumont's own book not only as a full record of his work, +but also as one of the best stories of aerial navigation that +has ever been written. Throughout all his experiments, he +adhered to the non-rigid type; his first dirigible made its +first flight on September 18th, 1898, starting from the Jardin +d'Acclimatation to the west of Paris; he calculated that his 3 +horse-power engine would yield sufficient power to enable him to +steer clear of the trees with which the starting-point was +surrounded, but, yielding to the advice of professional +aeronauts who were present, with regard to the placing of the +dirigible for his start, he tore the envelope against the trees. +Two days later, having repaired the balloon, he made an ascent of +1,300 feet. In descending, the hydrogen left in the balloon +contracted, and Santos-Dumont narrowly escaped a serious accident +in coming to the ground. + +His second machine, built in the early spring of 1899, held over +7,000 cubic feet of gas and gave a further 44 lbs. of ascensional +force. The balloon envelope was very long and very narrow; the +first attempt at flight was made in wind and rain, and the +weather caused sufficient contraction of the hydrogen for a wind +gust to double the machine up and toss it into the trees near its +starting-point. The inventor immediately set about the +construction of 'Santos-Dumont No. 3,' on which he made a number +of successful flights, beginning on November 13th, 1899. On the +last of his flights, he lost the rudder of the machine and made a +fortunate landing at Ivry. He did not repair the balloon, +considering it too clumsy in form and its motor too small. +Consequently No. 4 was constructed, being finished on the 1st, +August, 1900. It had a cubic capacity of 14,800 feet, a length +of 129 feet and greatest diameter of 16.7 feet, the power +plant being a 7 horse-power Buchet motor. Santos-Dumont sat on +a bicycle saddle fixed to the long bar suspended under the +machine, which also supported motor propeller, ballast; and +fuel. The experiment of placing the propeller at the stem +instead of at the stern was tried, and the motor gave it a speed +of 100 revolutions per minute. Professor Langley witnessed the +trials of the machine, which proved before the members of the +International Congress of Aeronautics, on September 19th, that +it was capable of holding its own against a strong wind. + +Finding that the cords with which his dirigible balloon cars were +suspended offered almost as much resistance to the air as did +the balloon itself, Santos-Dumont substituted piano wire and +found that the alteration constituted greater progress than many +a more showy device. He altered the shape and size of his No. 4 +to a certain extent and fitted a motor of 12 horse-power. +Gravity was controlled by shifting weights worked by a cord; +rudder and propeller were both placed at the stern. In +Santos-Dumont's book there is a certain amount of confusion +between the No. 4 and No. 5 airships, until he explains that +'No. 5' is the reconstructed 'No. 4.' It was with No. 5 that +he won the Encouragement Prize presented by the Scientific +Commission of the Paris Aero Club. This he devoted to the first +aeronaut who between May and October of 1900 should start from +St Cloud, round the Eiffel Tower, and return. If not won in +that year, the prize was to remain open the following year from +May 1st to October 1st, and so on annually until won. This was a +simplification of the conditions of the Deutsch Prize itself, the +winning of which involved a journey of 11 kilometres in 30 +minutes. + +The Santos-Dumont No. 5, which was in reality the modified No. 4 +with new keel, motor, and propeller, did the course of the +Deutsch Prize, but with it Santos-Dumont made no attempt to win +the prize until July of 1901, when he completed the course in 40 +minutes, but tore his balloon in landing. On the 8th August, +with his balloon leaking, he made a second attempt, and narrowly +escaped disaster, the airship being entirely wrecked. Thereupon +he built No. 6 with a cubic capacity of 22,239 feet and a lifting +power of 1,518 lbs. + +With this machine he won the Deutsch Prize on October 19th, +1901, starting with the disadvantage of a side wind of 20 feet +per second. He reached the Eiffel Tower in 9 minutes and, +through miscalculating his turn, only just missed colliding +with it. He got No. 6 under control again and succeeded in +getting back to his starting-point in 29 1/2 minutes, thus +winning the 125,000 francs which constituted the Deutsch Prize, +together with a similar sum granted to him by the Brazilian +Government for the exploit. The greater part of this money was +given by Santos-Dumont to charities. + +He went on building after this until he had made fourteen +non-rigid dirigibles; of these No. 12 was placed at the disposal +of the military authorities, while the rest, except for one that +was sold to an American and made only one trip, were matters of +experiment for their maker. His conclusions from his experiments +may be gathered from his own work:-- + +'On Friday, 31st July, 1903, Commandant Hirschauer and +Lieutenant-Colonel Bourdeaux spent the afternoon with me at my +airship station at Neuilly St James, where I had my three newest +airships--the racing 'No. 7,' the omnibus 'No. 10,' and the +runabout 'No. 9'--ready for their study. Briefly, I may say +that the opinions expressed by the representatives of the +Minister of War were so unreservedly favourable that a practical +test of a novel character was decided to be made. Should the +airship chosen pass successfully through it the result will be +conclusive of its military value. + +'Now that these particular experiments are leaving my exclusively +private control I will say no more of them than what has been +already published in the French press. The test will probably +consist of an attempt to enter one of the French frontier towns, +such as Belfort or Nancy, on the same day that the airship +leaves Paris. It will not, of course, be necessary to make the +whole journey in the airship. A military railway wagon may be +assigned to carry it, with its balloon uninflated, with tubes of +hydrogen to fill it, and with all the necessary machinery and +instruments arranged beside it. At some station a short +distance from the town to be entered the wagon may be uncoupled +from the train, and a sufficient number of soldiers accompanying +the officers will unload the airship and its appliances, +transport the whole to the nearest open space, and at once begin +inflating the balloon. Within two hours from quitting the train +the airship may be ready for its flight to the interior of the +technically-besieged town. + +'Such may be the outline of the task--a task presented +imperiously to French balloonists by the events of 1870-1, and +which all the devotion and science of the Tissandier brothers +failed to accomplish. To-day the problem may be set with better +hope of success. All the essential difficulties may be revived +by the marking out of a hostile zone around the town that must +be entered; from beyond the outer edge of this zone, then, the +airship will rise and take its flight--across it. + +'Will the airship be able to rise out of rifle range? I have +always been the first to insist that the normal place of the +airship is in low altitudes, and I shall have written this book +to little purpose if I have not shown the reader the real +dangers attending any brusque vertical mounting to considerable +heights. For this we have the terrible Severo accident before +our eyes. In particular, I have expressed astonishment at +hearing of experimenters rising to these altitudes without +adequate purpose in their early stages of experience with +dirigible balloons. All this is very different, however, from a +reasoned, cautious mounting, whose necessity has been foreseen +and prepared for.' + +Probably owing to the fact that his engines were not of +sufficient power, Santos-Dumont cannot be said to have solved +the problem of the military airship, although the French +Government bought one of his vessels. At the same time, he +accomplished much in furthering and inciting experiment with +dirigible airships, and he will always rank high among the +pioneers of aerostation. His experiments might have gone +further had not the Wright brothers' success in America and +French interest in the problem of the heavier-than-air machine +turned him from the study of dirigibles to that of the +aeroplane, in which also he takes high rank among the pioneers, +leaving the construction of a successful military dirigible to +such men as the Lebaudy brothers, Major Parseval, and Zeppelin. + + + +IV. THE MILITARY DIRIGIBLE + +Although French and German experiment in connection with the +production of an airship which should be suitable for military +purposes proceeded side by side, it is necessary to outline the +development in the two countries separately, owing to the +differing character of the work carried out. So far as France +is concerned, experiment began with the Lebaudy brothers, +originally sugar refiners, who turned their energies to airship +construction in 1899. Three years of work went to the production +of their first vessel, which was launched in 1902, having been +constructed by them together with a balloon manufacturer named +Surcouf and an engineer, Julliot. The Lebaudy airships were +what is known as semi-rigids, having a spar which ran +practically the full length of the gas bag to which it was +attached in such a way as to distribute the load evenly. The +car was suspended from the spar, at the rear end of which both +horizontal and vertical rudders were fixed, whilst stabilising +fins were provided at the stern of the gas envelope itself. The +first of the Lebaudy vessels was named the 'Jaune'; its length +was 183 feet and its maximum diameter 30 feet, while the cubic +capacity was 80,000 feet. The power unit was a 40 horse-power +Daimler motor, driving two propellers and giving a maximum speed +of 26 miles per hour. This vessel made 29 trips, the last of +which took place in November, 1902, when the airship was wrecked +through collision with a tree. + +The second airship of Lebaudy construction was 7 feet longer +than the first, and had a capacity of 94,000 cubic feet of gas +with a triple air bag of 17,500 cubic feet to compensate for +loss of gas; this latter was kept inflated by a rotary fan. The +vessel was eventually taken over by the French Government and +may be counted the first dirigible airship considered fit on its +tests for military service. + +Later vessels of the Lebaudy type were the 'Patrie' and +'Republique,' in which both size and method of construction +surpassed those of the two first attempts. The 'Patrie' was +fitted with a 60 horse-power engine which gave a speed of 28 +miles an hour, while the vessel had a radius of 280 miles, +carrying a crew of nine. In the winter of 1907 the 'Patrie' was +anchored at Verdun, and encountered a gale which broke her hold +on her mooring-ropes. She drifted derelict westward across +France, the Channel, and the British Isles, and was lost in the +Atlantic. + +The 'Republique' had an 80 horse-power motor, which, however, +only gave her the same speed as the 'Patrie.' She was launched +in July, 1908, and within three months came to an end which +constituted a tragedy for France. A propeller burst while the +vessel was in the air, and one blade, flying toward the +envelope, tore in it a great gash; the airship crashed to earth, +and the two officers and two non-commissioned officers who were +in the car were instantaneously killed. + +The Clement Bayard, and subsequently the Astra-Torres, +non-rigids, followed on the early Lebaudys and carried French +dirigible construction up to 1912. The Clement Bayard was a +simple non-rigid having four lobes at the stern end to assist +stability. These were found to retard the speed of the airship, +which in the second and more successful construction was driven +by a Clement Bayard motor of l00 horse-power at a speed of 30 +miles an hour. On August 23rd, 1909, while being tried for +acceptance by the military authorities, this vessel achieved a +record by flying at a height of 5,000 feet for two hours. The +Astra-Torres non-rigids were designed by a Spaniard, Senor +Torres, and built by the Astra Company. The envelope was of +trefoil shape, this being due to the interior rigging from the +suspension band; the exterior appearance is that of two lobes +side by side, overlaid by a third. The interior rigging, which +was adopted with a view to decreasing air resistance, supports a +low-hung car from the centre of the envelope; steering is +accomplished by means of horizontal planes fixed on the envelope +at the stern, and vertical planes depending beneath the envelope, +also at the stern end. + +One of the most successful of French pre-war dirigibles was a +Clement Bayard built in 1912. In this twin propellers were +placed at the front and horizontal and vertical rudders in a +sort of box formation under the envelope at the stern. The +envelope was stream-lined, while the car of the machine was +placed well forward with horizontal controlling planes above it +and immediately behind the propellers. This airship, which was +named 'Dupuy de Lome,' may be ranked as about the most +successful non-rigid dirigible constructed prior to the War. + +Experiments with non-rigids in Germany was mainly carried on by +Major Parseval, who produced his first vessel in 1906. The main +feature of this airship consisted in variation in length of the +suspension cables at the will of the operator, so that the +envelope could be given an upward tilt while the car remained +horizontal in order to give the vessel greater efficiency in +climbing. In this machine, the propeller was placed above and +forward of the car, and the controlling planes were fixed +directly to the envelope near the forward end. A second vessel +differed from the first mainly in the matter of its larger size, +variable suspension being again employed, together with a similar +method of control. The vessel was moderately successful, and +under Major Parseval's direction a third was constructed for +passenger carrying, with two engines of 120 horsepower, each +driving propellers of 13 feet diameter. This was the most +successful of the early German dirigibles; it made a number of +voyages with a dozen passengers in addition to its crew, as well +as proving its value for military purposes by use as a scout +machine in manoeuvres. Later Parsevals were constructed of +stream-line form, about 300 feet in length, and with engines +sufficiently powerful to give them speeds up to 50 miles an hour. + +Major Von Gross, commander of a Balloon Battalion, produced +semi-rigid dirigibles from 1907 onward. The second of these, +driven by two 75 horse-power Daimler motors, was capable of a +speed of 27 miles an hour; in September of 1908 she made a trip +from and back to Berlin which lasted 13 hours, in which period +she covered 176 miles with four passengers and reached a height +of 4,000 feet. Her successor, launched in April of 1909, +carried a wireless installation, and the next to this, driven by +four motors of 75 horse-power each, reached a speed of 45 miles +an hour. As this vessel was constructed for military purposes, +very few details either of its speed or method of construction +were made public. + +Practically all these vessels were discounted by the work of +Ferdinand von Zeppelin, who set out from the first with the idea +of constructing a rigid dirigible. Beginning in 1898, he built a +balloon on an aluminium framework covered with linen and silk, +and divided into interior compartments holding linen bags which +were capable of containing nearly 400,000 cubic feet of +hydrogen. The total length of this first Zeppelin airship was +420 feet and the diameter 38 feet. Two cars were rigidly +attached to the envelope, each carrying a 16 horse-power motor, +driving propellers which were rigidly connected to the aluminium +framework of the balloon. Vertical and horizontal screws were +used for lifting and forward driving and a sliding weight was +used to raise or lower the stem of the vessel out of the +horizontal in order to rise or descend without altering the load +by loss of ballast or the lift by loss of gas. + +The first trial of this vessel was made in July of 1900, and was +singularly unfortunate. The winch by which the sliding weight +was operated broke, and the balloon was so bent that the working +of the propellers was interfered with, as was the steering. A +speed of 13 feet per second was attained, but on descending, the +airship ran against some piles and was further damaged. Repairs +were completed by the end of September, 1900, and on a second +trial flight made on October 21st a speed of 30 feet per second +was reached. + +Zeppelin was far from satisfied with the performance of this +vessel, and he therefore set about collecting funds for the +construction of a second, which was completed in 1905. By this +time the internal combustion engine had been greatly improved, +and without any increase of weight, Zeppelin was able to instal +two motors of 85 horse-power each. The total capacity was +367,000 cubic feet of hydrogen, carried in 16 gas bags inside +the framework, and the weight of the whole construction was 9 +tons--a ton less than that of the first Zeppelin airship. Three +vertical planes at front and rear controlled horizontal +steering, while rise and fall was controlled by horizontal +planes arranged in box form. Accident attended the first trial +of this second airship, which took place over the Bodensee on +November 30th, 1905, 'It had been intended to tow the raft, to +which it was anchored, further from the shore against the wind. +But the water was too low to allow the use of the raft. The +balloon was therefore mounted on pontoons, pulled out into the +lake, and taken in tow by a motor-boat. It was caught by a +strong wind which was blowing from the shore, and driven ahead +at such a rate that it overtook the motor-boat. The tow rope +was therefore at once cut, but it unexpectedly formed into knots +and became entangled with the airship, pulling the front end +down into the water. The balloon was then caught by the wind +and lifted into the air, when the propellers were set in motion. +The front end was at this instant pointing in a downward +direction, and consequently it shot into the water, where it was +found necessary to open the valves.'[*] + +[*] Hildebrandt, Airships Past and Present. + +The damage done was repaired within six weeks, and the second +trial was made on January 17th, 1906. The lifting force was too +great for the weight, and the dirigible jumped immediately to +1,500 feet. The propellers were started, and the dirigible +brought to a lower level, when it was found possible to drive +against the wind. The steering arrangements were found too +sensitive, and the motors were stopped, when the vessel was +carried by the wind until it was over land--it had been intended +that the trial should be completed over water. A descent was +successfully accomplished and the dirigible was anchored for the +night, but a gale caused it so much damage that it had to be +broken up. It had achieved a speed of 30 feet per second with +the motors developing only 36 horse-power and, gathering from +this what speed might have been accomplished with the full 170 +horse-power, Zeppelin set about the construction of No. 3, with +which a number of successful voyages were made, proving the value +of the type for military purposes. + +No. 4 was the most notable of the early Zeppelins, as much on +account of its disastrous end as by reason of any superior merit +in comparison with No. 3. The main innovation consisted in +attaching a triangular keel to the under side of the envelope, +with two gaps beneath which the cars were suspended. Two Daimler +Mercedes motors of 110 horse-power each were placed one in each +car, and the vessel carried sufficient fuel for a 60-hour cruise +with the motors running at full speed. Each motor drove a pair +of three-bladed metal propellers rigidly attached to the +framework of the envelope and about 15 feet in diameter. There +was a vertical rudder at the stern of the envelope and horizontal +controlling planes were fixed on the sides of the envelope. The +best performances and the end of this dirigible were summarised +as follows by Major Squier:-- + +'Its best performances were two long trips performed during the +summer of 1908. The first, on July 4th, lasted exactly 12 +hours, during which time it covered a distance of 235 miles, +crossing the mountains to Lucerne and Zurich, and returning to +the balloon-house near Friedrichshafen, on Lake Constance. The +average speed on this trip was 32 miles per hour. On August +4th, this airship attempted a 24-hour flight, which was one of +the requirements made for its acceptance by the Government. It +left Friedrichshafen in the morning with the intention of +following the Rhine as far as Mainz, and then returning to its +starting-point, straight across the country. A stop of 3 hours +30 minutes was made in the afternoon of the first day on the +Rhine, to repair the engine. On the return, a second stop was +found necessary near Stuttgart, due to difficulties with the +motors, and some loss of gas. While anchored to the ground, a +storm arose which broke loose the anchorage, and, as the balloon +rose in the air, it exploded and took fire (due to causes which +have never been actually determined and published) and fell to +the ground, where it was completely destroyed. On this journey, +which lasted in all 31 hours 15 minutes, the airship was in the +air 20 hours 45 minutes, and covered a total distance of 378 +miles. + +'The patriotism of the German nation was aroused. Subscriptions +were immediately started, and in a short space of time a quarter +of a million pounds had been raised. A Zeppelin Society was +formed to direct the expenditure of this fund. Seventeen +thousand pounds has been expended in purchasing land near +Friedrichshafen; workshops were erected, and it was announced +that within one year the construction of eight airships of the +Zeppelin type would be completed. Since the disaster to +'Zeppelin IV.' the Crown Prince of Germany made a trip in +'Zeppelin No. 3,' which had been called back into service, and +within a very few days the German Emperor visited Friedrichshafen +for the purpose of seeing the airship in flight. He decorated +Count Zeppelin with the order of the Black Eagle. German +patriotism and enthusiasm has gone further, and the "German +Association for an Aerial Fleet" has been organised in +sections throughout the country. It announces its intention of +building 50 garages (hangars) for housing airships.' + +By January of 1909, with well over a quarter of a million in +hand for the construction of Zeppelin airships, No. 3 was again +brought out, probably in order to maintain public enthusiasm in +respect of the possible new engine of war. In March of that +year No. 3 made a voyage which lasted for 4 hours over and in +the vicinity of Lake Constance; it carried 26 passengers for a +distance of nearly 150 miles. + +Before the end of March, Count Zeppelin determined to voyage +from Friedrichshafen to Munich, together with the crew of the +airship and four military officers. Starting at four in the +morning and ascertaining their route from the lights of railway +stations and the ringing of bells in the towns passed over, the +journey was completed by nine o'clock, but a strong south-west +gale prevented the intended landing. The airship was driven +before the wind until three o'clock in the afternoon, when it +landed safely near Dingolfing; by the next morning the wind had +fallen considerably and the airship returned to Munich and +landed on the parade ground as originally intended. At about +3.30 in the afternoon, the homeward journey was begun, +Friedrichshafen being reached at about 7.30. + +These trials demonstrated that sufficient progress had been made +to justify the construction of Zeppelin airships for use with +the German army. No. 3 had been manoeuvred safely if not +successfully in half a gale of wind, and henceforth it was known +as 'SMS. Zeppelin I.,' at the bidding of the German Emperor, +while the construction of 'SMS. Zeppelin II.' was rapidly +proceeded with. The fifth construction of Count Zeppelin's was +446 feet in length, 42 1/2 feet in diameter, and contained +530,000 cubic feet of hydrogen gas in 17 separate compartments. +Trial flights were made on the 26th May, 1909, and a week later +she made a record voyage of 940 miles, the route being from Lake +Constance over Ulm, Nuremberg, Leipzig, Bitterfeld, Weimar, +Heilbronn, and Stuttgart, descending near Goppingen; the time +occupied in the flight was upwards of 38 hours. + +In landing, the airship collided with a pear-tree, which damaged +the bows and tore open two sections of the envelope, but repairs +on the spot enabled the return journey to Friedrichshafen to be +begun 24 hours later. In spite of the mishap the Zeppelin had +once more proved itself as a possible engine of war, and +thenceforth Germany pinned its faith to the dirigible, only +developing the aeroplane to such an extent as to keep abreast of +other nations. By the outbreak of war, nearly 30 Zeppelins had +been constructed; considerably more than half of these were +destroyed in various ways, but the experiments carried on with +each example of the type permitted of improvements being made. +The first fatality occurred in September, 1913, when the +fourteenth Zeppelin to be constructed, known as Naval Zeppelin +L.1, was wrecked in the North Sea by a sudden storm and her +crew of thirteen were drowned. About three weeks after this, +Naval Zeppelin L.2, the eighteenth in order of building, +exploded in mid-air while manoeuvring over Johannisthal. She +was carrying a crew of 25, who were all killed. + +By 1912 the success of the Zeppelin type brought imitators. +Chief among them was the Schutte-Lanz, a Mannheim firm, which +produced a rigid dirigible with a wooden framework, wire braced. +This was not a cylinder like the Zeppelin, but reverted to the +cigar shape and contained about the same amount of gas as the +Zeppelin type. The Schutte-Lanz was made with two gondolas +rigidly attached to the envelope in which the gas bags were +placed. The method of construction involved greater weight than +was the case with the Zeppelin, but the second of these vessels, +built with three gondolas containing engines, and a navigating +cabin built into the hull of the airship itself, proved quite +successful as a naval scout until wrecked on the islands off the +coast of Denmark late in 1914. The last Schutte-Lanz to be +constructed was used by the Germans for raiding England, and was +eventually brought down in flames at Cowley. + + + +V. BRITISH AIRSHIP DESIGN + +As was the case with the aeroplane, Great Britain left France +and Germany to make the running in the early days of airship +construction; the balloon section of the Royal Engineers was +compelled to confine its energies to work with balloons pure and +simple until well after the twentieth century had dawned, and +such experiments as were made in England were done by private +initiative. As far back as 1900 Doctor Barton built an airship +at the Alexandra Palace and voyaged across London in it. Four +years later Mr E. T. Willows of Cardiff produced the first +successful British dirigible, a semi-rigid 74 feet in length and +18 feet in diameter, engined with a 7 horse-power Peugot +twin-cylindered motor. This drove a two-bladed propeller at the +stern for propulsion, and also actuated a pair of auxiliary +propellers at the front which could be varied in their direction +so as to control the right and left movements of the airship. +This device was patented and the patent was taken over by the +British Government, which by 1908 found Mr Willow's work of +sufficient interest to regard it as furnishing data for +experiment at the balloon factory at Farnborough. In 1909, +Willows steered one of his dirigibles to London from Cardiff in +a little less than ten hours, making an average speed of over 14 +miles an hour. The best speed accomplished was probably +considerably greater than this, for at intervals of a few miles, +Willows descended near the earth to ascertain his whereabouts +with the help of a megaphone. It must be added that he carried +a compass in addition to his megaphone. He set out for Paris in +November of 1910, reached the French coast, and landed near +Douai. Some damage was sustained in this landing, but, after +repair, the trip to Paris was completed. + +Meanwhile the Government balloon factory at Farnborough began +airship construction in 1907; Colonel Capper, R.E., and S. F. +Cody were jointly concerned in the production of a semi-rigid. +Fifteen thicknesses of goldbeaters' skin--about the most +expensive covering obtainable--were used for the envelope, which +was 25 feet in diameter. A slight shower of rain in which the +airship was caught led to its wreckage, owing to the absorbent +quality of the goldbeaters' skin, whereupon Capper and Cody set +to work to reproduce the airship and its defects on a larger +scale. The first had been named 'Nulli Secundus' and the second +was named 'Nulli Secundus II.' Punch very appropriately +suggested that the first vessel ought to have been named 'Nulli +Primus,' while a possible third should be christened 'Nulli +Tertius.' 'Nulli Secundus II.' was fitted with a 100 horse-power +engine and had an envelope of 42 feet in diameter, the +goldbeaters' skin being covered in fabric and the car being +suspended by four bands which encircled the balloon envelope. +In October of 1907, 'Nulli Secundus II.' made a trial flight +from Farnborough to London and was anchored at the Crystal +Palace. The wind sprung up and took the vessel away from its +mooring ropes, wrecking it after the one flight. + +Stagnation followed until early in 1909, when a small airship +fitted with two 12 horse-power motors and named the 'Baby' was +turned out from the balloon factory. This was almost +egg-shaped, the blunt end being forward, and three inflated fins +being placed at the tail as control members. A long car with +rudder and elevator at its rear-end carried the engines and +crew; the 'Baby' made some fairly successful flights and gave a +good deal of useful data for the construction of later vessels. + +Next to this was 'Army Airship 2A 'launched early in 1910 and +larger, longer, and narrower in design than the Baby. The +engine was an 80 horse-power Green motor which drove two pairs +of propellers; small inflated control members were fitted at the +stern end of the envelope, which was 154 feet in length. The +suspended car was 84 feet long, carrying both engines and crew, +and the Willows idea of swivelling propellers for governing the +direction was used in this vessel. In June of that year a new, +small-type dirigible, the 'Beta,' was produced, driven by a 30 +horse-power Green engine with which she flew over 3,000 miles. +She was the most successful British dirigible constructed up to +that time, and her successor, the 'Gamma,' was built on similar +lines. The 'Gamma' was a larger vessel, however, produced in +1912, with flat, controlling fins and rudder at the rear end of +the envelope, and with the conventional long car suspended at +some distance beneath the gas bag. By this time, the mooring +mast, carrying a cap of which the concave side fitted over the +convex nose of the airship, had been originated. The cap was +swivelled, and, when attached to it, an airship was held nose on +to the wind, thus reducing by more than half the dangers +attendant on mooring dirigibles in the open. + +Private subscription under the auspices of the Morning Post got +together sufficient funds in 1910 for the purchase of a Lebaudy +airship, which was built in France, flown across the Channel, and +presented to the Army Airship Fleet. This dirigible was 337 feet +long, and was driven by two 135 horse-power Panhard motors, each +of which actuated two propellers. The journey from Moisson to +Aldershot was completed at a speed of 36 miles an hour, but the +airship was damaged while being towed into its shed. On May of +the following year, the Lebaudy was brought out for a flight, +but, in landing, the guide rope fouled in trees and sheds and +brought the airship broadside on to the wind; she was driven into +some trees and wrecked to such an exteent that rebuilding was +considered an impossibility. A Clement Bayard, bought by the +army airship section, became scrap after even less flying than +had been accomplished by the Lebaudy. + +In April of 1910,, the Admiralty determined on a naval air +service, and set about the production of rigid airships which +should be able to compete with Zeppelins as naval scouts. The +construction was entrusted to Vickers, Ltd., who set about the +task at their Barrow works and built something which, when tested +after a year's work, was found incapable of lifting its own +weight. This defect was remedied by a series of alterations, and +meanwhile the unofficial title of 'Mayfly' was given to the +vessel. + +Taken over by the Admiralty before she had passed any flying +tests, the 'Mayfly' was brought out on September 24th, 1911, for +a trial trip, being towed out from her shed by a tug. When ha]f +out from the shed, the envelope was caught by a light +cross-wind, and, in spite of the pull from the tug, the great +fabric broke in half, nearly drowning the crew, who had to dive +in order to get clear of the wreckage. + +There was considerable similarity in form, though not in +performance, between the Mayfly and the prewar Zeppelin. The +former was 510 feet in length, cylindrical in form, with a +diameter of 48 feet, and divided into 19 gas-bag compartments. +The motive power consisted of two 200 horse-power Wolseley +engines. After its failure, the Naval Air Service bought an +Astra-Torres airship from France and a Parseval from Germany, +both of which proved very useful in the early days of the War, +doing patrol work over the Channel before the Blimps came into +being. + +Early in 1915 the 'Blimp' or 'S.S.' type of coastal airship +was evolved in response to the demand for a vessel which could +be turned out quickly and in quantities. There was urgent +demand, voiced by Lord Fisher, for a type of vessel capable of +maintaining anti-submarine patrol off the British coasts, and +the first S.S. airships were made by combining a gasbag with +the most available type of aeroplane fuselage and engine, and +fitting steering gear. The 'Blimp' consisted of a B.E. fuselage +with engine and geared-down propeller, and seating for pilot and +observer, attached to an envelope about 150 feet in length. +With a speed of between 35 and 40 miles an hour, the 'Blimp' had +a cruising capacity of about ten hours; it was fitted with +wireless set, camera, machine-gun, and bombs, and for submarine +spotting and patrol work generally it proved invaluable, though +owing to low engine power and comparatively small size, its uses +were restricted to reasonably fair weather. For work farther out +at sea and in all weathers, airships known as the coast patrol +type, and more commonly as 'coastals,' were built, and later the +'N.S.' or North Sea type, still larger and more weather-worthy, +followed. By the time the last year of the War came, Britain +led the world in the design of non-rigid and semi-rigid +dirigibles. The 'S.S.' or 'Blimp' had been improved to a speed +of 50 miles an hour, carrying a crew of three, and the endurance +record for the type was 18 1/2 hours, while one of them had +reached a height of 10,000 feet. The North Sea type of +non-rigid was capable of travelling over 20 hours at full speed, +or forty hours at cruising speed, and the number of non-rigids +belonging to the British Navy exceeded that of any other +country. + +It was owing to the incapacity--apparent or real-- of the +British military or naval designers to produce a satisfactory +rigid airship that the 'N.S.' airship was evolved. The first of +this type was produced in 1916, and on her trials she was voted +an unqualified success, in consequence of which the building of +several more was pushed on. The envelope, of 360,000 cubic feet +capacity, was made on the Astra-Torres principle of three lobes, +giving a trefoil section. The ship carried four fins, to three +of which the elevator and rudder flaps were attached; petrol +tanks were placed inside the envelope, under which was rigged a +long covered-in car, built up of a light steel tubular framework +35 feet in length. The forward portion was covered with +duralumin sheeting, an aluminium alloy which, unlike aluminium +itself, is not affected by the action of sea air and water, and +the remainder with fabric laced to the framework. Windows and +port-holes were provided to give light to the crew, and the +controls and navigating instruments were placed forward, with the +sleeping accommodation aft. The engines were mounted in a power +unit structure, separate from the car and connected by wooden +gang ways supported by wire cables. A complete electrical +installation of two dynamos and batteries for lights, signalling +lamps, wireless, telephones, etc., was carried, and the motive +power consisted of either two 250 horse-power Rolls-Royce engines +or two 240 horse-power Fiat engines. The principal dimensions of +this type are length 262 feet, horizontal diameter 56 feet 9 +inches, vertical diameter 69 feet 3 inches. The gross lift is +24,300 lbs. and the disposable lift without crew, petrol, oil, +and ballast 8,500 lbs. The normal crew carried for patrol work +was ten officers and men. This type holds the record of 101 +hours continuous flight on patrol duty. + +In the matter of rigid design it was not until 1913 that the +British Admiralty got over the fact that the 'Mayfly' would not, +and decided on a further attempt at the construction of a rigid +dirigible. The contract for this was signed in March of 1914; +work was suspended in the following February and begun again in +July, 1915, but it was not until January of 1917 that the +ship was finished, while her trials were not completed until +March of 1917, when she was taken over by the Admiralty. The +details of the construction and trial of this vessel, known as +'No. 9,' go to show that she did not quite fill the contract +requirements in respect of disposable lift until a number of +alterations had been made. The contract specified that a speed +of at least 45 miles per hour was to be attained at full engine +power, while a minimum disposable lift of 5 tons was to be +available for movable weights, and the airship was to be capable +of rising to a height of 2,000 feet. Driven by four Wolseley +Maybach engines of 180 horse-power each, the lift of the vessel +was not sufficient, so it was decided to remove the two engines +in the after car and replace them by a single engine of 250 +horsepower. With this the vessel reached the contract speed of +45 miles per hour with a cruising radius of 18 hours, equivalent +to 800 miles when the engines were running at full speed. The +vessel served admirably as a training airship, for, by the time +she was completed, the No. 23 class of rigid airship had come to +being, and thus No. 9 was already out of date. + +Three of the 23 class were completed by the end of 1917; it was +stipulated that they should be built with a speed of at least 55 +miles per hour, a minimum disposable lift of 8 tons, and a +capability of rising at an average rate of not less than 1,000 +feet per minute to a height of 3,000 feet. The motive power +consisted of four 250 horse-power Rolls-Royce engines, one in +each of the forward and after cars and two in a centre car. +Four-bladed propellers were used throughout the ship. + +A 23X type followed on the 23 class, but by the time two ships +had been completed, this was practically obsolete. The No. 31 +class followed the 23X; it was built on Schutte-Lanz lines, 615 +feet in length, 66 feet diameter, and a million and a half cubic +feet capacity. The hull was similar to the later types of +Zeppelin in shape, with a tapering stern and a bluff, rounded +bow. Five cars each carrying a 250 horse-power Rolls-Royce +engine, driving a single fixed propeller, were fitted, and on +her trials R.31 performed well, especially in the matter of +speed. But the experiment of constructing in wood in the +Schutte-Lanz way adopted with this vessel resulted in failure +eventually, and the type was abandoned. + +Meanwhile, Germany had been pushing forward Zeppelin design and +straining every nerve in the improvement of rigid dirigible +construction, until L.33 was evolved; she was generally known as +a super-Zeppelin, and on September 24th, 1916, six weeks +after her launching, she was damaged by gun-fire in a raid over +London, being eventually compelled to come to earth at Little +Wigborough in Essex. The crew gave themselves up after having +set fire to the ship, and though the fabric was totally +destroyed, the structure of the hull remained intact, so that +just as Germany was able to evolve the Gotha bomber from the +HandleyPage delivered at Lille, British naval constructors were +able to evolve the R.33 type of airship from the Zeppelin +framework delivered at Little Wigborough. Two vessels, R.33 and +R.34, were laid down for completion; three others were also put +down for construction, but, while R.33 and R.34 were built +almost entirely from the data gathered from the wrecked L.33, +the three later vessels embody more modern design, including a +number of improvements, and more especially greater disposable +lift. It has been commented that while the British authorities +were building R.33 and R.34, Germany constructed 30 Zeppelins on +4 slips, for which reason it may be reckoned a matter for +congratulation that the rigid airship did not decide the fate of +the War. The following particulars of construction of the R.33 +and R.34 types are as given by Major Whale in his survey of +British Airships:-- + +'In all its main features the hull structure of R.33 and R.34 +follows the design of the wrecked German Zeppelin airship L.33. +'The hull follows more nearly a true stream-line shape than in +the previous ships constructed of duralumin, in which a greater +proportion of the greater length was parallel-sided. The +Germans adopted this new shape from the Schutte-Lanz design and +have not departed from this practice. This consists of a short, +parallel body with a long, rounded bow and a long tapering stem +culminating in a point. The overall length of the ship is 643 +feet with a diameter of 79 feet and an extreme height of 92 +feet. + +'The type of girders in this class has been much altered from +those in previous ships. The hull is fitted with an internal +triangular keel throughout practically the entire length. This +forms the main corridor of the ship, and is fitted with a +footway down the centre for its entire length. It contains water +ballast and petrol tanks, bomb storage and crew accommodation, +and the various control wires, petrol pipes, and electric leads +are carried along the lower part. + +'Throughout this internal corridor runs a bridge girder, from +which the petrol and water ballast tanks are supported. These +tanks are so arranged that they can be dropped clear of the +ship. Amidships is the cabin space with sufficient room for a +crew of twenty-five. Hammocks can be swung from the bridge +girder before mentioned. + +'In accordance with the latest Zeppelin practice, monoplane +rudders and elevators are fitted to the horizontal and vertical +fins. + +'The ship is supported in the air by nineteen gas bags, which +give a total capacity of approximately two million cubic feet of +gas. The gross lift works out at approximately 59 1/2 tons, of +which the total fixed weight is 33 tons, giving a disposable +lift of 26 1/2 tons. + +'The arrangement of cars is as follows: At the forward end the +control car is slung, which contains all navigating instruments +and the various controls. Adjoining this is the wireless cabin, +which is also fitted for wireless telephony. Immediately aft of +this is the forward power car containing one engine, which gives +the appearance that the whole is one large car. + +'Amidships are two wing cars, each containing a single engine. +These are small and just accommodate the engines with sufficient +room for mechanics to attend to them. Further aft is another +larger car which contains an auxiliary control position and two +engines. + +'It will thus be seen that five engines are installed in the +ship; these are all of the same type and horsepower, namely, 250 +horse-power Sunbeam. R.33 was constructed by Messrs Armstrong, +Whitworth, Ltd.; while her sister ship R.34 was built by Messrs +Beardmore on the Clyde.' + +Of the two vessels, R.34 appeared rather more airworthy than her +sister ship; the lift of the ship justified the carrying of a +greater quantity of fuel than had been provided for, and, as she +was considered suitable for making a Transatlantic crossing, +extra petrol tanks were fitted in the hull and a new type of +outer cover was fitted with a view to her making the Atlantic +crossing. She made a 21-hour cruise over the North of England +and the South of Scotland at the end of May, 1919, and +subsequently went for a longer cruise over Denmark, the Baltic, +and the north coast of Germany, remaining in the air for 56 hours +in spite of very bad weather conditions. Finally, July 2nd was +selected as the starting date for the cross Atlantic flight; the +vessel was commanded by Major G. H. Scott, A.F.C., with Captain +G. S. Greenland as first officer, Second-Lieut. H. F. Luck as +second officer, and Lieut. J. D. Shotter as engineer officer. +There were also on board Brig.-Gen. E. P. Maitland, representing +the Air Ministry, Major J. E. M. Pritchard, representing the +Admiralty, and Lieut.-Col. W. H. Hemsley of the Army Aviation +Department. In addition to eight tons of petrol, R.34 carried a +total number of 30 persons from East Fortune to Long Island, N.Y. + +There being no shed in America capable of accommodating the +airship, she had to be moored in the open for refilling with fuel +and gas, and to make the return journey almost immediately. + +Brig.-Gen. Maitland's account of the flight, in itself a record +as interesting as valuable, divides the outward journey into two +main stages, the first from East Fortune to Trinity Bay, +Newfoundland, a distance of 2,050 sea miles, and the second and +more difficult stage to Mineola Field, Long Island, 1,080 sea +miles. An easy journey was experienced until Newfoundland was +reached, but then storms and electrical disturbances rendered it +necessary to alter the course, in consequence of which petrol +began to run short. Head winds rendered the shortage still more +acute, and on Saturday, July 5th, a wireless signal was sent out +asking for destroyers to stand by to tow. However, after an +anxious night, R.33 landed safely at Mineola Field at 9.55 a.m. +on July 6th, having accomplished the journey in 108 hours 12 +minutes. + +She remained at Mineola until midnight of July 9th, when, +although it had been intended that a start should be made by +daylight for the benefit of New York spectators, an approaching +storm caused preparations to be advanced for immediate +departure. She set out at 5.57 a.m. by British summer time, +and flew over New York in the full glare of hundreds of +searchlights before heading out over the Atlantic. A following +wind assisted the return voyage, and on July 13th, at 7.57 a.m., +R.34 anchored at Pulham, Norfolk, having made the return journey +in 75 hours 3 minutes, and proved the suitability of the +dirigible for Transatlantic commercial work. R.80, launched on +July 19th, 1920, afforded further proof, if this were needed. + +It is to be noted that nearly all the disasters to airships have +been caused by launching and landing-- the type is safe enough +in the air, under its own power, but its bulk renders it +unwieldy for ground handling. The German system of handling +Zeppelins in and out of their sheds is, so far, the best +devised: this consists of heavy trucks running on rails through +the sheds and out at either end; on descending, the trucks are +run out, and the airship is securely attached to them outside +the shed; the trucks are then run back into the shed, taking the +airship with them, and preventing any possibility of the wind +driving the envelope against the side of the shed before it is +safely housed; the reverse process is adopted in launching, +which is thus rendered as simple as it is safe. + + + +VI. THE AIRSHIP COMMERCIALLY + +Prior to the war period, between the years 1910 and 1914, a +German undertaking called the Deutsche Luftfahrt Actien +Gesellschaft conducted a commercial Zeppelin service in which +four airships known as the Sachsan, Hansa, Victoria Louise, and +Schwaben were used. During the four years of its work, the +company carried over 17,000 passengers, and over 100,000 miles +were flown without incurring one fatality and with only minor +and unavoidable accidents to the vessels composing the service. +Although a number of English notabilities made voyages in these +airships, the success of this only experiment in commercial +aerostation seems to have been forgotten since the war. There +was beyond doubt a military aim in this apparently peaceful use +of Zeppelin airships; it is past question now that all Germany's +mechanical development in respect of land sea, and air transport +in the years immediately preceding the war, was accomplished +with the ulterior aim of military conquest, but, at the same +time, the running of this service afforded proof of the +possibility of establishing a dirigible service for peaceful +ends, and afforded proof too, of the value of the dirigible as a +vessel of purely commercial utility. + +In considering the possibility of a commercial dirigible +service, it is necessary always to bear in mind the +disadvantages of first cost and upkeep as compared with the +aeroplane. The building of a modern rigid is an exceedingly +costly undertaking, and the provision of an efficient supply of +hydrogen gas to keep its compartments filled is a very large +item in upkeep of which the heavier-than-air machine goes free. +Yet the future of commercial aeronautics so far would seem to +lie with the dirigible where very long voyages are in question. +No matter how the aeroplane may be improved, the possibility of +engine failure always remains as a danger for work over water. +In seaplane or flying boat form, the danger is still present in +a rough sea, though in the American Transatlantic flight, N.C.3, +taxi-ing 300 miles to the Azores after having fallen to the +water, proved that this danger is not so acute as is generally +assumed. Yet the multiple-engined rigid, as R.34 showed on her +return voyage, may have part of her power plant put out of +action altogether and still complete her voyage very +successfully, which, in the case of mail carrying and services +run strictly to time, gives her an enormous advantage over the +heavier-than-air machine. + +'For commercial purposes,' General Sykes has remarked, 'the +airship is eminently adapted for long distance journeys +involving non-stop flights. It has this inherent advantage over +the aeroplane, that while there appears to be a limit to the +range of the aeroplane as at present constructed, there is +practically no limit whatever to that of the airship, as this +can be overcome by merely increasing the size. It thus appears +that for such journeys as crossing the Atlantic, or crossing the +Pacific from the west coast of America to Australia or Japan, +the airship will be peculiarly suitable. It having been +conceded that the scope of the airship is long distance travel, +the only type which need be considered for this purpose is the +rigid. The rigid airship is still in an embryonic state, but +sufficient has already been accomplished in this country, and +more particularly in Germany, to show that with increased +capacity there is no reason why, within a few years' time, +airships should not be built capable of completing the circuit +of the globe and of conveying sufficient passengers and +merchandise to render such an undertaking a paying proposition.' + +The British R.38 class, embodying the latest improvements in +airship design outside Germany, gives a gross lift per airship +of 85 tons and a net lift of about 45 tons. The capacity of +the gas bags is about two and three-quarter million cubic feet, +and, travelling at the rate of 45 miles per hour, the cruising +range of the vessel is estimated at 8.8 days. Six engines, each +of 350 horse-power, admit of an extreme speed of 70 miles per +hour if necessary. + +The last word in German design is exemplified in the rigids L.70 +and L.71, together with the commercial airship 'Bodensee.' +Previous to the construction of these, the L.65 type is +noteworthy as being the first Zeppelin in which direct drive of +the propeller was introduced, together with an improved and +lighter type of car. L.70 built in 1918 and destroyed by the +British naval forces, had a speed of about 75 miles per hour; +L.71 had a maximum speed of 72 miles per hour, a gas bag +capacity of 2,420,000 cubic feet, and a length of 743 feet, +while the total lift was 73 tons. Progress in design is best +shown by the progress in useful load; in the L.70 and L.71 +class, this has been increased to 58.3 per cent, while in the +Bodensee it was ever higher. + +As was shown in R.34's American flight, the main problem in +connection with the commercial use of dirigibles is that of +mooring in the open. The nearest to a solution of this problem, +so far, consists in the mast carrying a swivelling cap; this has +been tried in the British service with a non-rigid airship, +which was attached to a mast in open country in a gale of 52 +miles an hour without the slightest damage to the airship. In +its commercial form, the mast would probably take the form of a +tower, at the top of which the cap would revolve so that the +airship should always face the wind, the tower being used for +embarkation and disembarkation of passengers and the provision +of fuel and gas. Such a system would render sheds unnecessary +except in case of repairs, and would enormously decrease the +establishment charges of any commercial airship. + +All this, however, is hypothetical. Remains the airship of +to-day, developed far beyond the promise of five years ago, +capable, as has been proved by its achievements both in Britain +and in Germany, of undertaking practically any given voyage with +success. + + + +VII. KITE BALLOONS + +As far back as the period of the Napoleonic wars, the balloon +was given a place in warfare, but up to the Franco-Prussian +Prussian War of 1870-71 its use was intermittent. The Federal +forces made use of balloons to a small extent in the American +Civil War; they came to great prominence in the siege of Paris, +carrying out upwards of three million letters and sundry carrier +pigeons which took back messages into the besieged city. +Meanwhile, as captive balloons, the German and other armies used +them for observation and the direction of artillery fire. In +this work the ordinary spherical balloon was at a grave +disadvantage; if a gust of wind struck it, the balloon was blown +downward and down wind, generally twirling in the air and +upsetting any calculations and estimates that might be made by +the observers, while in a wind of 25 miles an hour it could not +rise at all. The rotatory movement caused by wind was stopped +by an experimenter in the Russo-Japanese war, who fixed to the +captive observation balloons a fin which acted as a rudder. This +did not stop the balloon from being blown downward and away from +its mooring station, but this tendency was overcome by a +modification designed in Germany by the Parseval-Siegsfield +Company, which originated what has since become familiar as the +'Sausage' or kite balloon. This is so arranged that the forward +end is tilted up into the wind, and the underside of the gas +bag, acting as a plane, gives the balloon a lifting tendency in +a wind, thus counteracting the tendency of the wind to blow it +downward and away from its mooring station. Smaller bags are +fitted at the lower and rear end of the balloon with openings +that face into the wind; these are thus kept inflated, and they +serve the purpose of a rudder, keeping the kite balloon steady +in the air. + +Various types of kite balloon have been introduced; the original +German Parseval-Siegsfield had a single air bag at the stern +end, which was modified to two, three, or more lobes in later +varieties, while an American experimental design attempted to do +away with the attached lobes altogether by stringing out a +series of small air bags, kite fashion, in rear of the main +envelope. At the beginning of the War, Germany alone had kite +balloons, for the authorities of the Allied armies con-sidered +that the bulk of such a vessel rendered it too conspicuous a +mark to permit of its being serviceable. The Belgian arm alone +possessed two which, on being put into service, were found +extremely useful. The French followed by constructing kite +balloons at Chalais Meudon, and then, after some months of +hostilities and with the example of the Royal Naval Air Service +to encourage them, the British military authorities finally took +up the construction and use of kite balloons for +artillery-spotting and general observation purposes. Although +many were brought down by gun-fire, their uses far outweighed +their disadvantages, and toward the end of the War, hardly a +mile of front was without its 'Sausage.' + +For naval work, kite balloons were carried in a specially +constructed hold in the forepart of certain vessels; when +required for use, the covering of the hold was removed, the +kite balloon inflated and released to the required height by +means of winches as in the case of the land work. The +perfecting of the 'Coastal' and N.S. types of airship, together +with the extension of wireless telephony between airship and +cruiser or other warship, in all probability will render the use +of the kite balloon unnecessary in connection with naval +scouting. But, during the War, neither wireless telephony nor +naval airships had developed sufficiently to render the Navy +independent of any means that might come to hand, and the +fitting of kite balloons in this fashion filled a need of the +times. + +A necessary accessory of the kite balloon is the parachute, +which has a long history. Da Vinci and Veranzio appear to have +been the first exponents, the first in the theory and the latter +in the practice of parachuting. Montgolfier experimented at +Annonay before he constructed his first hot air-balloon, and in +1783 a certain Lenormand dropped from a tree in a parachute. +Blanchard the balloonist made a spectacle of parachuting, and +made it a financial success; Cocking, in 1836, attempted to use +an inverted form of parachute; taken up to a height of 3,000 +feet, he was cut adrift, when the framework of the parachute +collapsed and Cocking was killed. + +The rate of fall is slow in parachuting to the ground. Frau +Poitevin, making a descent from a height of 6,000 feet, took 45 +minutes to reach the ground, and, when she alighted, her +husband, who had taken her up, had nearly got his balloon packed +up. Robertson, another parachutist is said to have descended +from a height of 10,000 feet in 35 minutes, or at a rate of +nearly 5 feet per second. During the War Brigadier-General +Maitland made a parachute descent from a height of 10,000 feet, +the time taken being about 20 minutes. + +The parachute was developed considerably during the War period, +the main requirement, that of certainty in opening, being +considerably developed. Considered a necessary accessory for +kite balloons, the parachute was also partially adopted for use +with aeroplanes in the later War period, when it was contended +that if a machine were shot down in flames, its occupants would +be given a far better chance of escape if they had parachutes. +Various trials were made to demonstrate the extreme efficiency +of the parachute in modern form, one of them being a descent +from the upper ways of the Tower Bridge to the waters of the +Thames, in which short distance the 'Guardian Angel' type of +parachute opened and cushioned the descent for its user. + +For dirigibles, balloons, and kite balloons the parachute is +an essential. It would seem to be equally essential in the case +of heavier-than-air machines, but this point is still debated. +Certainly it affords the occupant of a falling aeroplane a +chance, no matter how slender, of reaching the ground in safety, +and, for that reason, it would seem to have a place in aviation +as well as in aerostation. + + + +PART IV. ENGINE DEVELOPMENT + +I. THE VERTICAL TYPE + +The balloon was but a year old when the brothers Robert, in 1784 +attempted propulsion of an aerial vehicle by hand-power, +and succeeded, to a certain extent, since they were able to make +progress when there was only a slight wind to counteract their +work. But, as may be easily understood, the manual power +provided gave but a very slow speed, and in any wind it all the +would-be airship became an uncontrolled balloon. + +Henson and Stringfellow, with their light steam engines, were +first to attempt conquest of the problem of mechanical +propulsion in the air; their work in this direction is so fully +linked up with their constructed models that it has been +outlined in the section dealing with the development of the +aeroplane. But, very shortly after these two began, there came +into the field a Monsieur Henri Giffard, who first achieved +success in the propulsion by mechanical means of dirigible +balloons, for his was the first airship to fly against the wind. +He employed a small steam-engine developing about 3 horse-power +and weighing 350 lbs. with boiler, fitting the whole in a car +suspended from the gas-bag of his dirigible. The propeller which +this engine worked was 11 feet in diameter, and the inventor, who +made several flights, obtained a speed of 6 miles an hour against +a slight wind. The power was not sufficient to render the +invention practicable, as the dirigible could only be used in +calm weather, but Giffard was sufficiently encouraged by his +results to get out plans for immense dirigibles, which through +lack of funds he was unable to construct. When, later, his +invention of the steam-injector gave him the means he desired, he +became blind, and in 1882 died, having built but the one famous +dirigible. + +This appears to have been the only instance of a steam engine +being fitted to a dirigible; the inherent disadvantage of this +form of motive power is that a boiler to generate the steam must +be carried, and this, together with the weight of water and +fuel, renders the steam engine uneconomical in relation to the +lift either of plane or gas-bag. Again, even if the weight +could be brought down to a reasonable amount, the attention +required by steam plant renders it undesirable as a motive power +for aircraft when compared with the internal combustion engine. + +Maxim, in Artificial and Natural Flight, details the engine +which he constructed for use with his giant experimental flying +machine, and his description is worthy of reproduction since it +is that of the only steam engine besides Giffard's, and apart +from those used for the propulsion of models, designed for +driving an aeroplane. 'In 1889,' Maxim says, 'I had my +attention drawn to some very thin, strong, and comparatively +cheap tubes which were being made in France, and it was only +after I had seen these tubes that I seriously considered the +question of making a flying machine. I obtained a large +quantity of them and found that they were very light, that they +would stand enormously high pressures, and generate a very large +quantity of steam. Upon going into a mathematical calculation of +the whole subject, I found that it would be possible to make a +machine on the aeroplane system, driven by a steam engine, which +would be sufficiently strong to lift itself into the air. I +first made drawings of a steam engine, and a pair of these +engines was afterwards made. These engines are constructed, for +the most part, of a very high grade of cast steel, the cylinders +being only 3/32 of an inch thick, the crank shafts hollow, and +every part as strong and light as possible. They are compound, +each having a high-pressure piston with an area of 20 square +inches, a low-pressure piston of 50.26 square inches, and a +common stroke of 1 foot. When first finished they were found to +weigh 300 lbs. each; but after putting on the oil cups, felting, +painting, and making some slight alterations, the weight was +brought up to 320 lbs. each, or a total of 640 lbs. for the +two engines, which have since developed 362 horsepower with a +steam pressure of 320 lbs. per square inch.' + +The result is remarkable, being less than 2 lbs. weight per +horse-power, especially when one considers the state of +development to which the steam engine had attained at the time +these experiments were made. The fining down of the internal +combustion engine, which has done so much to solve the problems +of power in relation to weight for use with aircraft, had not +then been begun, and Maxim had nothing to guide him, so far as +work on the part of his predecessors was concerned, save the +experimental engines of Stringfellow, which, being constructed +on so small a scale in comparison with his own, afforded little +guidance. Concerning the factor of power, he says: 'When first +designing this engine, I did not know how much power I might +require from it. I thought that in some cases it might be +necessary to allow the high-pressure steam to enter the +low-pressure cylinder direct, but as this would involve a +considerable loss, I constructed a species of injector. This +injector may be so adjusted (hat when the steam in the boiler +rises above a certain predetermined point, say 300 lbs., to the +square inch, it opens a valve and escapes past the high-pressure +cylinder instead of blowing off at the safety valve. In +escaping through this valve, a fall of about 200 lbs. pressure +per square inch is made to do work on the surrounding steam and +drive it forward in the pipe, producing a pressure on the +low-pressure piston considerably higher than the back-pressure +on the high-pressure piston. In this way a portion of the work +which would otherwise be lost is utilised, and it is possible, +with an unlimited supply of steam, to cause the engines to +develop an enormous amount of power.' + +With regard to boilers, Maxim writes, + +'The first boiler which I made was constructed something on the +Herreshof principle, but instead of having one simple pipe in +one very long coil, I used a series of very small and light +pipes, connected in such a manner that there was a rapid +circulation through the whole--the tubes increasing in size and +number as the steam was generated. I intended that there should +be a pressure of about 100 lbs. more on the feed water end of +the series than on the steam end, and I believed that this +difference in pressure would be sufficient to ensure direct and +positive circulation through every tube in the series. The first +boiler was exceedingly light, but the workmanship, as far as +putting the tubes together was concerned, was very bad, and it +was found impossible to so adjust the supply of water as to make +dry steam without overheating and destroying the tubes. + +'Before making another boiler I obtained a quantity of copper +tubes, about 8 feet long, 3/8 inch external diameter, and 1/50 of +an inch thick. I subjected about 100 of these tubes to an +internal pressure of 1 ton per square inch of cold kerosene oil, +and as none of them leaked I did not test any more, but +commenced my experiments by placing some of them in a white-hot +petroleum fire. I found that I could evaporate as much as 26 +1/2 lbs. of water per square foot of heating surface per hour, +and that with a forced circulation, although the quantity of +water passing was very small but positive, there was no danger +of overheating. I conducted many experiments with a pressure of +over 400 lbs. per square inch, but none of the tubes failed. +I then mounted a single tube in a white-hot furnace, also with a +water circulation, and found that it only burst under steam at a +pressure of 1,650 lbs. per square inch. A large boiler, +having about 800 square feet of heating surface, including the +feed-water heater, was then constructed. This boiler is about 4 +1/2 feet wide at the bottom, 8 feet long and 6 feet high. It +weighs, with the casing, the dome, and the smoke stack and +connections, a little less than 1,000 lbs. The water first +passes through a system of small tubes--1/4 inch in diameter and +1/60 inch thick--which were placed at the top of the boiler and +immediately over the large tubes.... This feed-water heater is +found to be very effective. It utilises the heat of the +products of combustion after they have passed through the boiler +proper and greatly reduces their temperature, while the +feed-water enters the boiler at a temperature of about 250 F. A +forced circulation is maintained in the boiler, the feed-water +entering through a spring valve, the spring valve being adjusted +in such a manner that the pressure on the water is always 30 +lbs. per square inch in excess of the boiler pressure. This +fall of 30 lbs. in pressure acts upon the surrounding hot water +which has already passed through the tubes, and drives it down +through a vertical outside tube, thus ensuring a positive and +rapid circulation through all the tubes. This apparatus is +found to act extremely well.' + +Thus Maxim, who with this engine as power for his large +aeroplane achieved free flight once, as a matter of experiment, +though for what distance or time the machine was actually off +the ground is matter for debate, since it only got free by +tearing up the rails which were to have held it down in the +experiment. Here, however, was a steam engine which was +practicable for use in the air, obviously, and only the rapid +success of the internal combustion engine prevented the +steam-producing type from being developed toward perfection. + +The first designers of internal combustion engines, knowing +nothing of the petrol of these days, constructed their examples +with a view to using gas as fuel. As far back as 1872 Herr Paul +Haenlein obtained a speed of about 10 miles an hour with a +balloon propelled by an internal combustion engine, of which the +fuel was gas obtained from the balloon itself. The engine in +this case was of the Lenoir type, developing some 6 horse-power, +and, obviously, Haenlein's flights were purely experimental and +of short duration, since he used the gas that sustained him and +decreased the lifting power of his balloon with every stroke of +the piston of his engine. No further progress appears to have +been made with the gas-consuming type of internal combustion +engine for work with aircraft; this type has the disadvantage of +requiring either a gas-producer or a large storage capacity for +the gas, either of which makes the total weight of the power +plant much greater than that of a petrol engine. The latter type +also requires less attention when working, and the fuel is more +convenient both for carrying and in the matter of carburation. + +The first airship propelled by the present-day type of internal +combustion engine was constructed by Baumgarten and Wolfert in +1879 at Leipzig, the engine being made by Daimler with a view to +working on benzine--petrol as a fuel had not then come to its +own. The construction of this engine is interesting since it was +one of the first of Daimler's make, and it was the development +brought about by the experimental series of which this engine +was one that led to the success of the motor-car in very few +years, incidentally leading to that fining down of the internal +combustion engine which has facilitated the development of the +aeroplane with such remarkable rapidity. Owing to the faulty +construction of the airship no useful information was obtained +from Daimler's pioneer installation, as the vessel got out of +control immediately after it was first launched for flight, and +was wrecked. Subsequent attempts at mechanically-propelled +flight by Wolfert ended, in 1897, in the balloon being set on +fire by an explosion of benzine vapour, resulting in the death +of both the aeronauts. + +Daimler, from 1882 onward, devoted his attention to the +perfecting of the small, high-speed petrol engine for motor-car +work, and owing to his efforts, together with those of other +pioneer engine-builders, the motorcar was made a success. In a +few years the weight of this type of engine was reduced from near +on a hundred pounds per horse-power to less than a tenth of that +weight, but considerable further improvement had to be made +before an engine suitable for use with aircraft was evolved. + +The increase in power of the engines fitted to airships has made +steady progress from the outset; Haenlein's engine developed +about 6 horse-power; the Santos-Dumont airship of 1898 was +propelled by a motor of 4 horse-power; in 1902 the Lebaudy +airship was fitted with an engine of 40 horse-power, while, in +1910, the Lebaudy brothers fitted an engine of nearly 300 +horsepower to the airship they were then constructing--1,400 +horse-power was common in the airships of the War period, and +the later British rigids developed yet more. + +Before passing on to consideration of the petrol-driven type of +engine, it is necessary to accord brief mention to the dirigible +constructed in 1884 by Gaston and Albert Tissandier, who at +Grenelle, France, achieved a directed flight in a wind of 8 +miles an hour, obtaining their power for the propeller from 1 1/3 +horse-power Siemens electric motor, which weighed 121 lbs. and +took its current from a bichromate battery weighing 496 lbs. A +two-bladed propeller, 9 feet in diameter, was used, and the +horse-power output was estimated to have run up to 1 1/2 as the +dirigible successfully described a semicircle in a wind of 8 +miles an hour, subsequently making headway transversely to a wind +of 7 miles an hour. The dirigible with which this motor was used +was of the conventional pointed-end type, with a length of 92 +feet, diameter of 30 feet, and capacity of 37,440 cubic feet of +gas. Commandant Renard, of the French army balloon corps, +followed up Tissandier's attempt in the next year--1885--making a +trip from Chalais-Meudon to Paris and returning to the point of +departure quite successfully. In this case the motive power was +derived from an electric plant of the type used by the +Tissandiers, weighing altogether 1,174 lbs., and developing 9 +horsepower. A speed of 14 miles an hour was attained with this +dirigible, which had a length of 165 feet, diameter of 27 feet, +and capacity of 65,836 cubic feet of gas. + +Reverting to the petrol-fed type again, it is to be noted that +Santos-Dumont was practically the first to develop the use of +the ordinary automobile engine for air work--his work is of such +importance that it has been considered best to treat of it as +one whole, and details of the power plants are included in the +account of his experiments. Coming to the Lebaudy brothers and +their work, their engine of 1902 was a 40 horse-power Daimler, +four-cylindered; it was virtually a large edition of the Daimler +car engine, the arrangement of the various details being on the +lines usually adopted for the standard Daimler type of that +period. The cylinders were fully water-jacketed, and no special +attempt toward securing lightness for air work appears to have +been made. + +The fining down of detail that brought weight to such limits as +would fit the engine for work with heavier-than-air craft +appears to have waited for the brothers Wright. Toward the end +of 1903 they fitted to their first practicable flying machine the +engine which made the historic first aeroplane flight; this +engine developed 30 horse-power, and weighed only about 7 lbs. +per horse-power developed, its design and workmanship being far +ahead of any previous design in this respect, with the exception +of the remarkable engine, designed by Manly, installed in +Langley's ill-fated aeroplane--or 'aerodrome,' as he preferred to +call it--tried in 1903. + +The light weight of the Wright brothers' engine did not +necessitate a high number of revolutions per minute to get the +requisite power; the speed was only 1,300 revolutions per +minute, which, with a piston stroke of 3.94 inches, was quite +moderate. Four cylinders were used, the cylinder diameter being +4.42 inches; the engine was of the vertical type, arranged to +drive two propellers at a rate of about 350 revolutions per +minute, gearing being accomplished by means of chain drive from +crank-shaft end to propeller spindle. + +The methods adopted by the Wrights for obtaining a light-weight +engine were of considerable interest, in view of the fact that +the honour of first achieving flight by means of the driven plane +belongs to them--unless Ader actually flew as he claimed. The +cylinders of this first Wright engine were separate castings of +steel, and only the barrels were jacketed, this being done by +fixing loose, thin aluminium covers round the outside of each +cylinder. The combustion head and valve pockets were cast +together with the cylinder barrel, and were not water cooled. +The inlet valves were of the automatic type, arranged on the tops +of the cylinders, while the exhaust valves were also overhead, +operated by rockers and push-rods. The pistons and piston rings +were of the ordinary type, made of cast-iron, and the connecting +rods were circular in form, with a hole drilled down the middle +of each to reduce the weight. + +Necessity for increasing power and ever lighter weight in +relation to the power produced has led to the evolution of a +number of different designs of internal combustion engines. It +was quickly realised that increasing the number of cylinders on +an engine was a better way of getting more power than that of +increasing the cylinder diameter, as the greater number of +cylinders gives better torque-even turning effect--as well as +keeping down the weight--this latter because the bigger +cylinders must be more stoutly constructed than the small sizes; +this fact has led to the construction of engines having as many +as eighteen cylinders, arranged in three parallel rows in order +to keep the length of crankshaft within reasonable limits. The +aero engine of to-day may, roughly, be divided into four +classes: these are the V type, in which two rows of cylinders +are set parallel at a certain angle to each other; the radial +type, which consists of cylinders arranged radially and +remaining stationary while the crankshaft revolves; the rotary, +where the cylinders are disposed round a common centre and +revolve round a stationary shaft, and the vertical type, of four +or six cylinders--seldom more than this--arranged in one row. A +modification of the V type is the eighteen-cylindered engine-- +the Sunbeam is one of the best examples--in which three rows of +cylinders are set parallel to each other, working on a common +crankshaft. The development these four types started with that +of the vertical--the simplest of all; the V, radial, and rotary +types came after the vertical, in the order given. + +The evolution of the motor-car led to the adoption of the +vertical type of internal combustion engine in preference to any +other, and it followed naturally that vertical engines should be +first used for aeroplane propulsion, as by taking an engine that +had been developed to some extent, and adapting it to its new +work, the problem of mechanical flight was rendered easier than +if a totally new type had had to be evolved. It was quickly +realised--by the Wrights, in fact-that the minimum of weight per +horse-power was the prime requirement for the successful +development of heavier-than-air machines, and at the same time +it was equally apparent that the utmost reliability had to be +obtained from the engine, while a third requisite was economy, +in order to reduce the weight of petrol necessary for flight. + +Daimler, working steadily toward the improvement of the internal +combustion engine, had made considerable progress by the end of +last century. His two-cylinder engine of 1897 was approaching +to the present-day type, except as regards the method of +ignition; the cylinders had 3.55 inch diameter, with a 4.75 inch +piston stroke, and the engine was rated at 4.5 brake horse-power, +though it probably developed more than this in actual running at +its rated speed of 800 revolutions per minute. Power was limited +by the inlet and exhaust passages, which, compared with +present-day practice, were very small. The heavy castings of +which the engine was made up are accounted for by the necessity +for considering foundry practice of the time, for in 1897 +castings were far below the present-day standard. The crank-case +of this two-cylinder vertical Daimler engine was the only part +made of aluminium, and even with this no attempt was made to +attain lightness, for a circular flange was cast at the bottom to +form a stand for the engine during machining and erection. The +general design can be followed from the sectional views, and +these will show, too, that ignition was by means of a hot tube on +the cylinder head, which had to be heated with a blow-lamp before +starting the engine. With all its well known and hated troubles, +at that time tube ignition had an advantage over the magneto, and +the coil and accumulator system, in reliability; sparking plugs, +too, were not so reliable then as they are now. Daimler fitted a +very simple type of carburettor to this engine, consisting only +of a float with a single jet placed in the air passage. It may +be said that this twin-cylindered vertical was the first of the +series from which has been evolved the Mercedes-Daimler car and +airship engines, built in sizes up to and even beyond 240 +horse-power. + +In 1901 the development of the petrol engine was still so slight +that it did not admit of the construction, by any European +maker, of an engine weighing less than 12 lbs. per horse-power. +Manly, working at the instance of Professor Langley, produced a +five-cylindered radial type engine, in which both the design and +workmanship showed a remarkable advance in construction. At 950 +revolutions per minute it developed 52.4 horse-power, weighing +only 2.4 pounds per horse-power; it was a very remarkable +achievement in engine design, considering the power developed in +relation to the total weight, and it was, too, an interruption +in the development of the vertical type which showed that there +were other equally great possibilities in design. + +In England, the first vertical aero-engine of note was that +designed by Green, the cylinder dimensions being 4.15 inch +diameter by 4.75 stroke--a fairly complete idea of this engine +can be obtained from the accompanying diagrams. At a speed of +1,160 revolutions per minute it developed 35 brake horse-power, +and by accelerating up to 1,220 revolutions per minute a maximum +of 40 brake horse-power could be obtained--the first-mentioned +was the rated working speed of the engine for continuous runs. +A flywheel, weighing 23.5 lbs., was fitted to the engine, and +this, together with the ignition system, brought the weight up +to 188 lbs., giving 5.4 lbs. per horse-power. In comparison with +the engine fitted to the Wrights' aeroplane a greater power was +obtained from approximately the same cylinder volume, and an +appreciable saving in weight had also been effected. The +illustration shows the arrangement of the vertical valves at the +top of the cylinder and the overhead cam shaft, while the +position of the carburettor and inlet pipes can be also seen. +The water jackets were formed by thin copper casings, each +cylinder being separate and having its independent jacket rigidly +fastened to the cylinder at the top only, thus allowing for free +expansion of the casing; the joint at the bottom end was formed +by sliding the jacket over a rubber ring. Each cylinder was +bolted to the crank-case and set out of line with the crankshaft, +so that the crank has passed over the upper dead centre by the +time that the piston is at the top of its stroke when receiving +the full force of fuel explosion. The advantage of this +desaxe setting is that the pressure in the cylinder acts on the +crank-pin with a more effective leverage during that part of the +stroke when that pressure is highest, and in addition the side +pressure of the piston on the cylinder wall, due to the thrust of +the connecting rod, is reduced. Possibly the charging of the +cylinder is also more complete by this arrangement, owing to the +slower movement of the piston at the bottom of its stroke +allowing time for an increased charge of mixture to enter the +cylinder. + +A 60 horse-power engine was also made, having four vertical +cylinders, each with a diameter of 5.5 inches and stroke of 5.75 +inches, developing its rated power at 1,100 revolutions per +minute. By accelerating up to 1,200 revolutions per minute 70 +brake horsepower could be obtained, and a maximum of 80 brake +horse-power was actually attained with the type. The flywheel, +fitted as with the original 35 horse-power engine, weighed 37 +lbs.; with this and with the ignition system the total weight of +the engine was only 250 lbs., or 4.2 lbs. per horse-power at +the normal rating. In this design, however, low weight in +relation to power was not the ruling factor, for Green gave more +attention to reliability and economy of fuel consumption, which +latter was approximately 0.6 pint of petrol per brake +horse-power per hour. Both the oil for lubricating the bearings +and the water for cooling the cylinders were circulated by +pumps, and all parts of the valve gear, etc., were completely +enclosed for protection from dust. + +A later development of the Green engine was a six-cylindered +vertical, cylinder dimensions being 5.5 inch diameter by 6 inch +stroke, developing 120 brake horsepower when running at 1,250 +revolutions per minute. The total weight of the engine with +ignition system 398 was 440 lbs., or 3.66 lbs. per horse-power. +One of these engines was used on the machine which, in 1909, won +the prize of L1,000 for the first circular mile flight, and it +may be noted, too, that S. F. Cody, making the circuit of England +in 1911, used a four-cylinder Green engine. Again, it was a +Green engine that in 1914 won the L5,000 prize offered for the +best aero engine in the Naval and Military aeroplane engine +competition. + +Manufacture of the Green engines, in the period of the War, had +standardised to the production of three types. Two of these were +six-cylinder models, giving respectively 100 and 150 brake +horse-power, and the third was a twelve-cylindered model rated +at 275 brake horse-power. + +In 1910 J. S. Critchley compiled a list showing the types of +engine then being manufactured; twenty-two out of a total of +seventy-six were of the four-cylindered vertical type, and in +addition to these there were two six-cylindered verticals. +The sizes of the four-cylinder types ranged from 26 up to 118 +brake horse-power; fourteen of them developed less than 50 +horse-power, and only two developed over 100 horse-power. + +It became apparent, even in the early stages of heavier-than-air +flying, that four-cylinder engines did not produce the even +torque that was required for the rotation of the power shaft, +even though a flywheel was fitted to the engine. With this type +of engine the breakage of air-screws was of frequent occurrence, +and an engine having a more regular rotation was sought, both +for this and to avoid the excessive vibration often experienced +with the four-cylinder type. Another, point that forced itself +on engine builders was that the increased power which was +becoming necessary for the propulsion of aircraft made an +increase in the number of cylinders essential, in order to obtain +a light engine. An instance of the weight reduction obtainable +in using six cylinders instead of four is shown in Critchley's +list, for one of the four-cylinder engines developed 118.5 brake +horse-power and weighed 1,100 lbs., whereas a six-cylinder engine +by the same manufacturer developed 117.5 brake horse-power with a +weight of 880 lbs., the respective cylinder dimensions being +7.48 diameter by 9.06 stroke for the four-cylinder engine, and +6.1 diameter by 7.28 stroke for the six-cylinder type. + +A list of aeroplane engines, prepared in 1912 by Graham Clark, +showed that, out of the total number of 112 engines then +being manufactured, forty-two were of the vertical type, and of +this number twenty-four had four-cylinders while sixteen were +six-cylindered. The German aeroplane engine trials were held a +year later, and sixty-six engines entered the competition, +fourteen of these being made with air-cooled cylinders. All of +the ten engines that were chosen for the final trials were of +the water-cooled type, and the first place was won by a Benz +four-cylinder vertical engine which developed 102 brake +horse-power at 1,288 revolutions per minute. The cylinder +dimensions of this engine were 5.1 inch diameter by 7.1 inch +stroke, and the weight of the engine worked out at 3.4 lbs. per +brake horse-power. During the trials the full-load petrol +consumption was 0.53 pint per horse-power per hour, and the +amount of lubricating oil used was 0.0385 pint per brake +horse-power per hour. In general construction this Benz engine +was somewhat similar to the Green engine already described; the +overhead valves, fitted in the tops of the cylinders, were +similarly arranged, as was the cam-shaft; two springs were +fitted to each of the valves to guard against the possibility of +the engine being put out of action by breakage of one of the +springs, and ignition was obtained by two high-tension magnetos +giving simultaneous sparks in each cylinder by means of two +sparking plugs--this dual ignition reduced the possibility of +ignition troubles. The cylinder jackets were made of welded +sheet steel so fitted around the cylinder that the head was also +water-cooled, and the jackets were corrugated in the middle to +admit of independent expansion. Even the lubrication system was +duplicated, two sets of pumps being used, one to circulate the +main supply of lubricating oil, and the other to give a +continuous supply of fresh oil to the bearings, so that if the +supply from one pump failed the other could still maintain +effective lubrication. + +Development of the early Daimler type brought about the +four-cylinder vertical Mercedes-Daimler engine of 85 horse-power, +with cylinders of 5.5 diameter with 5.9 inch stroke, the +cylinders being cast in two pairs. The overhead arrangement of +valves was adopted, and in later designs push-rods were +eliminated, the overhead cam-shaft being adopted in their place. +By 1914 the four-cylinder Mercedes-Daimler had been partially +displaced from favour by a six-cylindered model, made in two +sizes; the first of these gave a nominal brake horse-power of 80, +having cylinders of 4.1 inches diameter by 5.5 inches stroke; the +second type developed 100 horse-power with cylinders 4.7 inches +in diameter and 5.5 inches stroke, both types being run at 1,200 +revolutions per minute. The cylinders of both these types were +cast in pairs, and, instead of the water jackets forming part of +the casting, as in the design of the original four-cylinder +Mercedes-Daimler engine, they were made of steel welded to +flanges on the cylinders. Steel pistons, fitted with cast-iron +rings, were used, and the overhead arrangement of valves and +cam-shaft was adopted. About 0.55 pint per brake horse-power per +hour was the usual fuel consumption necessary to full load +running, and the engine was also economical as regards the +consumption of lubricating oil, the lubricating system being +'forced' for all parts, including the cam-shaft. The shape of +these engines was very well suited for work with aircraft, being +narrow enough to admit of a streamline form being obtained, while +all the accessories could be so mounted as to produce little or +no wind resistance, and very little obstruction to the pilot's +view. + +The eight-cylinder Mercedes-Daimler engine, used for airship +propulsion during the War, developed 240 brake horse-power at +1,100 revolutions per minute; the cylinder dimensions were 6.88 +diameter by 6.5 stroke--one of the instances in which the short +stroke in relation to bore was very noticeable. + +Other instances of successful vertical design-the types already +detailed are fully sufficient to give particulars of the type +generally--are the Panhard, Chenu, Maybach, N.A.G., Argus, +Mulag, and the well-known Austro-Daimler, which by 1917 was +being copied in every combatant country. There are also the +later Wright engines, and in America the Wisconsin six-cylinder +vertical, weighing well under 4 lbs. per horse-power, is +evidence of the progress made with this first type of aero +engine to develop. + + + +II. THE VEE TYPE + +An offshoot from the vertical type, doubling the power of this +with only a very slight--if any--increase in the length of +crankshaft, the Vee or diagonal type of aero engine leaped to +success through the insistent demand for greater power. +Although the design came after that of the vertical engine, by +1910, according to Critchley's list of aero engines, there +were more Vee type engines being made than any other type, +twenty-five sizes being given in the list, with an average +rating of 57.4 brake horse-power. + +The arrangement of the cylinders in Vee form over the +crankshaft, enabling the pistons of each pair of opposite +cylinders to act upon the same crank pin, permits of a very +short, compact engine being built, and also permits of reduction +of the weight per horsepower, comparing this with that of the +vertical type of engine, with one row of cylinders. Further, at +the introduction of this type of engine it was seen that +crankshaft vibration, an evil of the early vertical engines, was +practically eliminated, as was the want of longitudinal +stiffness that characterised the higher-powered vertical +engines. + +Of the Vee type engines shown in Critchley's list in 1910 +nineteen different sizes were constructed with eight cylinders, +and with horse-powers ranging from thirty to just over the +hundred; the lightest of these weighed 2.9 lbs. per +horse-power--a considerable advance in design on the average +vertical engine, in this respect of weight per horse-power. +There were also two sixteen-cylinder engines of Vee design, the +larger of which developed 134 horse-power with a weight of only 2 +lbs. per brake horse-power. Subsequent developments have +indicated that this type, with the further development from it of +the double-Vee, or engine with three rows of cylinders, is likely +to become the standard design of aero engine where high powers +are required. The construction permits of placing every part so +that it is easy of access, and the form of the engine implies +very little head resistance, while it can be placed on the +machine--supposing that machine to be of the single-engine +type--in such a way that the view of the pilot is very little +obstructed while in flight. + +An even torque, or great uniformity of rotation, is transmitted +to the air-screw by these engines, while the design also permits +of such good balance of the engine itself that vibration is +practically eliminated. The angle between the two rows of +cylinders is varied according to the number of cylinders, in +order to give working impulses at equal angles of rotation and +thus provide even torque; this angle is determined by dividing +the number of degrees in a circle by the number of cylinders in +either row of the engine. In an eight-cylindered Vee type +engine, the angle between the cylinders is 90 degrees; if it is +a twelve-cylindered engine, the angle drops to 60 degrees. + +One of the earliest of the British-built Vee type engines was an +eight-cylinder 50 horse-power by the Wolseley Company, +constructed in 1908 with a cylinder bore of 3.75 inches and +stroke of 5 inches, running at a normal speed of 1,350 +revolutions per minute. With this engine, a gearing was +introduced to enable the propeller to run at a lower speed than +that of the engine, the slight loss of efficiency caused by the +friction of the gearing being compensated by the slower speed of +the air-screw, which had higher efficiency than would have been +the case if it had been run at the engine speed. The ratio of +the gearing--that is, the speed of the air-screw relatively to +that of the engine, could be chosen so as to suit exactly the +requirements of the air-screw, and the gearing itself, on this +engine, was accomplished on the half-speed shaft actuating the +valves. + +Very soon after this first design had been tried out, a second +Vee type engine was produced which, at 1,200 revolutions per +minute, developed 60 horse-power; the size of this engine was +practically identical with that of its forerunner, the only +exception being an increase of half an inch in the cylinder +stroke--a very long stroke of piston in relation to the bore of +the cylinder. In the first of these two engines, which was +designed for airship propulsion, the weight had been about 8 +lbs. per brake horse-power, no special attempt appearing to +have been made to fine down for extreme lightness; in this 60 +horse-power design, the weight was reduced to 6.1 lbs. per +horse-power, counting the latter as normally rated; the +engine actually gave a maximum of 75 brake horse-power, reducing +the ratio of weight to power very considerably below the figure +given. + +The accompanying diagram illustrates a later Wolseley model, end +elevation, the eight-cylindered 120 horse-power Vee type aero +engine of the early war period. With this engine, each crank +pin has two connecting rods bearing on it, these being placed +side by side and connected to the pistons of opposite cylinders +and the two cylinders of the pair are staggered by an amount +equal to the width of the connecting rod bearing, to afford +accommodation for the rods. The crankshaft was a nickel chrome +steel forging, machined hollow, with four crank pins set at 180 +degrees to each other, and carried in three bearings lined with +anti-friction metal. The connecting rods were made of tubular +nickel chrome steel, and the pistons of drawn steel, each being +fitted with four piston rings. Of these the two rings nearest to +the piston head were of the ordinary cast-iron type, while the +others were of phosphor bronze, so arranged as to take the side +thrust of the piston. The cylinders were of steel, arranged in +two groups or rows of four, the angular distance between them +being 90 degrees. In the space above the crankshaft, between the +cylinder rows, was placed the valve-operating mechanism, together +with the carburettor and ignition system, thus rendering this a +very compact and accessible engine. The combustion heads of the +cylinders were made of cast-iron, screwed into the steel cylinder +barrels; the water-jacket was of spun aluminium, with one end +fitting over the combustion head and the other free to slide on +the cylinder; the water-joint at the lower end was made tight by +a Dermatine ring carried between small flanges formed on the +cylinder barrel. Overhead valves were adopted, and in order to +make these as large as possible the combustion chamber was made +slightly larger in diameter than the cylinder, and the valves set +at an angle. Dual ignition was fitted in each cylinder, coil and +accumulator being used for starting and as a reserve in case of +failure of the high-tension magneto system fitted for normal +running. There was a double set of lubricating pumps, ensuring +continuity of the oil supply to all the bearings of the engine. + +The feature most noteworthy in connection with the running of +this type of engine was its flexibility; the normal output of +power was obtained with 1,150 revolutions per minute of the +crankshaft, but, by accelerating up to 1,400 revolutions, a +maximum of 147 brake horse-power could be obtained. The weight +was about 5 lbs. per horse-power, the cylinder dimensions being +5 inches bore by 7 inches stroke. Economy in running was +obtained, the fuel consumption being 0.58 pint per brake +horse-power per hour at full load, with an expenditure of about +0.075 pint of lubricating oil per brake horse-power per hour. + +Another Wolseley Vee type that was standardised was a 90 +horse-power eight-cylinder engine running at 1,800 revolutions +per minute, with a reducing gear introduced by fitting the air +screw on the half-speed shaft. First made semi-cooled--the +exhaust valve was left air-cooled, and then entirely +water-jacketed--this engine demonstrated the advantage of full +water cooling, for under the latter condition the same power was +developed with cylinders a quarter of an inch less in diameter +than in the semi-cooled pattern; at the same time the weight was +brought down to 4 1/2 lbs. per horsepower. + +A different but equally efficient type of Vee design was the +Dorman engine, of which an end elevation is shown; this +developed 80 brake horse-power at a speed of 1,300 revolutions +per minute, with a cylinder bore of 5 inches; each cylinder was +made in cast-iron in one piece with the combustion chamber, the +barrel only being water-jacketed. Auxiliary exhaust ports were +adopted, the holes through the cylinder wall being uncovered by +the piston at the bottom of its stroke--the piston, 4.75 inches +in length, was longer than its stroke, so that these ports were +covered when it was at the top of the cylinder. The exhaust +discharged through the ports into a belt surrounding the +cylinder, the belts on the cylinders being connected so that the +exhaust gases were taken through a single pipe. The air was +drawn through the crank case, before reaching the carburettor, +this having the effect of cooling the oil in the crank case as +well as warming the air and thus assisting in vaporising the +petrol for each charge of the cylinders. The inlet and exhaust +valves were of the overhead type, as may be gathered from the +diagram, and in spite of cast-iron cylinders being employed a +light design was obtained, the total weight with radiator, +piping, and water being only 5.5 lbs. per horse-power. + +Here was the antithesis of the Wolseley type in the matter of +bore in relation to stroke; from about 1907 up to the beginning +of the war, and even later, there was controversy as to which +type--that in which the bore exceeded the stroke, or vice +versa--gave greater efficiency. The short-stroke enthusiasts +pointed to the high piston speed of the long-stroke type, while +those who favoured the latter design contended that full power +could not be obtained from each explosion in the short-stroke +type of cylinder. It is now generally conceded that the +long-stroke engine yields higher efficiency, and in addition to +this, so far as car engines are concerned, the method of rating +horse-power in relation to bore without taking stroke into +account has given the long-stroke engine an advantage, actual +horse-power with a long stroke engine being in excess of the +nominal rating. This may have had some influence on aero engine +design, but, however this may have been, the long-stroke engine +has gradually come to favour, and its rival has taken second +place. + +For some time pride of place among British Vee type engines was +held by the Sunbeam Company, which, owing to the genius of Louis +Coatalen, together with the very high standard of construction +maintained by the firm, achieved records and fame in the middle +and later periods of the war. Their 225 horse-power +twelve-cylinder engine ran at a normal speed of 2,000 revolutions +per minute; the air screw was driven through gearing at half this +speed, its shaft being separate from the timing gear and carried +in ball-bearings on the nose-piece of the engine. The cylinders +were of cast-iron, entirely water-cooled; a thin casing formed +the water-jacket, and a very light design was obtained, the +weight being only 3.2 lbs. per horse-power. The first engine of +Sunbeam design had eight cylinders and developed 150 horse-power +at 2,000 revolutions per minute; the final type of Vee design +produced during the war was twelve-cylindered, and yielded 310 +horse-power with cylinders 4.3 inches bore by 6.4 inches stroke. +Evidence in favour of the long-stroke engine is afforded in this +type as regards economy of working; under full load, working at +2,000 revolutions per minute, the consumption was 0.55 pints of +fuel per brake horse-power per hour, which seems to indicate that +the long stroke permitted of full use being made of the power +resulting from each explosion, in spite of the high rate of speed +of the piston. + +Developing from the Vee type, the eighteen-cylinder 475 brake +horse-power engine, designed during the war, represented +for a time the limit of power obtainable from a single plant. +It was water-cooled throughout, and the ignition to each +cylinder was duplicated; this engine proved fully efficient, and +economical in fuel consumption. It was largely used for +seaplane work, where reliability was fully as necessary as high +power. + +The abnormal needs of the war period brought many British firms +into the ranks of Vee-type engine-builders, and, apart from +those mentioned, the most notable types produced are the +Rolls-Royce and the Napier. The first mentioned of these firms, +previous to 1914 had concentrated entirely on car engines, and +their very high standard of production in this department of +internal combustion engine work led, once they took up the +making of aero engines, to extreme efficiency both of design and +workmanship. The first experimental aero engine, of what became +known as the 'Eagle' type, was of Vee design--it was completed +in March of 1915--and was so successful that it was standardised +for quantity production. How far the original was from the +perfection subsequently ascertained is shown by the steady +increase in developed horse-power of the type; originally +designed to develop 200 horse-power, it was developed and +improved before its first practical trial in October of 1915, +when it developed 255 horsepower on a brake test. Research and +experiment produced still further improvements, for, without any +enlargement of the dimensions, or radical alteration in design, +the power of the engine was brought up to 266 horse-power by +March of 1916, the rate of revolutions of 1,800 per minute being +maintained throughout. July, 1916 gave 284 horse-power; by the +cud of the year this had been increased to 322 horse-power; by +September of 1917 the increase was to 350 horse-power, and by +February of 1918 then 'Eagle' type of engine was rated at 360 +horse-power, at which standard it stayed. But there is no more +remarkable development in engine design than this, a 75 per cent +increase of power in the same engine in a period of less than +three years. + +To meet the demand for a smaller type of engine for use on +training machines, the Rolls-Royce firm produced the 'Hawk' +Vee-type engine of 100 horsepower, and, intermediately between +this and the 'Eagle,' the 'Falcon' engine came to being with an +original rated horse-power of 205 at 1,800 revolutions per +minute, in April of 1916. Here was another case of growth of +power in the same engine through research, almost similar to +that of the 'Eagle' type, for by July of 1918 the 'Falcon' was +developing 285 horse-power with no radical alteration of +design. Finally, in response to the constant demand for +increase of power in a single plant, the Rolls-Royce company +designed and produced the 'Condor' type of engine, which yielded +600 horse-power on its first test in August of 1918. The +cessation of hostilities and consequent falling off in the +demand for extremely high-powered plants prevented the 'Condor' +being developed to its limit, as had been the 'Falcon' and +'Eagle' types. + +The 'Eagle 'engine was fitted to the two Handley-Page +aeroplanes--which made flights from England to India--it was +virtually standard on the Handley-Page bombers of the later War +period, though to a certain extent the American 'Liberty' engine +was also used. Its chief record, however, is that of being the +type fitted to the Vickers-Vimy aeroplane which made the first +Atlantic flight, covering the distance of 1,880 miles at a speed +averaging 117 miles an hour. + +The Napier Company specialised on one type of engine from the +outset, a power plant which became known as the 'Lion' engine, +giving 450 horse-power with twelve cylinders arranged in three +rows of four each. Considering the engine as 'dry,' or without +fuel and accessories, an abnormally light weight per +horse-power--only 1.89 lbs.--was attained when running at the +normal rate of revolution. The cylinders and water-jackets are +of steel, and there is fitted a detachable aluminium cylinder +head containing inlet and exhaust valves and valve actuating +mechanism; pistons are of aluminium alloy, and there are two +inlet and two exhaust valves to each cylinder, the whole of the +valve mechanism being enclosed in an oil-tight aluminium case. +Connecting rods and crankshaft are of steel, the latter being +machined from a solid steel forging and carried in five roller +bearings and one plain bearing at the forward end. The front end +of the crank-case encloses reduction gear for the propeller +shaft, together with the shaft and bearings. There are two +suction and one pressure type oil pumps driven through gears at +half-engine speed, and two 12 spark magnetos, giving 2 sparks in +each cylinder. + +The cylinders are set with the central row vertical, and the two +side rows at angles of 60 degrees each; cylinder bore is 5 1/2 +inches, and stroke 5 1/8 inches; the normal rate of revolution +is 1,350 per minute, and the reducing gear gives one revolution +of the propeller shaft to 1.52 revolutions of crankshaft. Fuel +consumption is 0.48lbs. of fuel per brake horse-power hour at +full load, and oil consumption is 0.020 lbs. per brake horsepower +hour. The dry weight of the engine, complete with propeller +boss, carburettors, and induction pipes, is 850 lbs., and the +gross weight in running order, with fuel and oil for six hours +working, is 2,671 lbs., exclusive of cooling water. + +To this engine belongs an altitude record of 30,500 feet, made at +Martlesham, near Ipswich, on January 2nd, 1919, by Captain Lang, +R.A.F., the climb being accomplished in 66 minutes 15 seconds. +Previous to this, the altitude record was held by an Italian +pilot, who made 25,800 feet in an hour and 57 minutes in 1916. +Lang's climb was stopped through the pressure of air, at the +altitude he reached, being insufficient for driving the small +propellers on the machine which worked the petrol and oil pumps, +or he might have made the height said to have been attained by +Major Schroeder on February 27th, 1920, at Dayton, Ohio. +Schroeder is said to have reached an altitude of 36,020 feet on a +Napier biplane, and, owing to failure of the oxygen supply, to +have lost consciousness, fallen five miles, righted his machine +when 2,000 feet in the air, and alighted successfully. Major +Schroeder is an American. + +Turning back a little, and considering other than British design +of Vee and double-Vee or 'Broad arrow' type of engine, the +Renault firm from the earliest days devoted considerable +attention to the development of this type, their air-cooled +engines having been notable examples from the earliest days of +heavier-than-air machines. In 1910 they were making three sizes +of eight-cylindered Vee-type engines, and by 1915 they had +increased to the manufacture of five sizes, ranging from 25 to +100 brake horse-power, the largest of the five sizes having +twelve cylinders but still retaining the air-cooled principle. +The De Dion firm, also, made Vee-type engines in 1914, being +represented by an 80 horse-power eight-cylindered engine, +air-cooled, and a 150 horse-power, also of eight cylinders, +water-cooled, running at a normal rate of 1,600 revolutions per +minute. Another notable example of French construction was the +Panhard and Levassor 100 horse-power eight-cylinder Vee engine, +developing its rated power at 1,500 revolutions per minute, and +having the--for that time--low weight of 4.4 lbs. per +horse-power. + +American Vee design has followed the British fairly cclosely; +the Curtiss Company produced originally a 75 horse-power +eight-cylinder Vee type running at 1,200 revolutions per minute, +supplementing this with a 170 horse-power engine running at +1,600 revolutions per minute, and later with a twelve-cylinder +model Vee type, developing 300 horse-power at 1,500 revolutions +per minute, with cylinder bore of 5 inches and stroke of 7 +inches. An exceptional type of American design was the Kemp Vee +engine of 80 horse-power in which the cylinders were cooled by a +current of air obtained from a fan at the forward end of the +engine. With cylinders of 4.25 inches bore and 4.75 inches +stroke, the rater power was developed at 1,150 revolutions per +minute, and with the engine complete the weight was only 4.75 +lbs. per horse-power. + + + +III. THE RADIAL TYPE + +The very first successful design of internal combustion aero +engine made was that of Charles Manly, who built a five-cylinder +radial engine in 1901 for use with Langley's 'aerodrome,' as the +latter inventor decided to call what has since become known as +the aeroplane. Manly made a number of experiments, and finally +decided on radial design, in which the cylinders are so rayed +round a central crank-pin that the pistons act successively upon +it; by this arrangement a very short and compact engine is +obtained, with a minimum of weight, and a regular crankshaft +rotation and perfect balance of inertia forces. + +When Manly designed his radial engine, high speed internal +combustion engines were in their infancy, and the difficulties in +construction can be partly realised when the lack of +manufacturing methods for this high-class engine work, and the +lack of experimental data on the various materials, are taken +into account. During its tests, Manly's engine developed 52.4 +brake horsepower at a speed of 950 revolutions per minute, with +the remarkably low weight of only 2.4 lbs. per horsepower; this +latter was increased to 3.6 lbs. when the engine was completed by +the addition of ignition system, radiator, petrol tank, and all +accessories, together with the cooling water for the cylinders. + +In Manly's engine, the cylinders were of steel, machined outside +and inside to 1/16 of an inch thickness; on the side of cylinder, +at the top end, the valve chamber was brazed, being machined +from a solid forging, The casing which formed the water-jacket +was of sheet steel, 1/50 of an inch in thickness, and this also +was brazed on the cylinder and to the valve chamber. Automatic +inlet valves were fitted, and the exhaust valves were operated +by a cam which had two points, 180 degrees apart; the cam was +rotated in the opposite direction to the engine at one-quarter +engine speed. Ignition was obtained by using a one-spark coil +and vibrator for all cylinders, with a distributor to select the +right cylinder for each spark--this was before the days of the +high-tension magneto and the almost perfect ignition systems that +makers now employ. The scheme of ignition for this engine was +originated by Manly himself, and he also designed the sparking +plugs fitted in the tops of the cylinders. Through fear of +trouble resulting if the steel pistons worked on the steel +cylinders, cast iron liners were introduced in the latter, 1/16 +of an inch thick. + +The connecting rods of this engine were of virtually the same +type as is employed on nearly all modern radial engines. The +rod for one cylinder had a bearing along the whole of the crank +pin, and its end enclosed the pin; the other four rods had +bearings upon the end of the first rod, and did not touch the +crank pin. The accompanying diagram shows this construction, +together with the means employed for securing the ends of the +four rods--the collars were placed in position after the rods +had been put on. The bearings of these rods did not receive any +of the rubbing effect due to the rotation of the crank pin, the +rubbing on them being only that of the small angular displacement +of the rods during each revolution; thus there was no difficulty +experienced with the lubrication. + +Another early example of the radial type of engine was the +French Anzani, of which type one was fitted to the machine with +which Bleriot first crossed the English Channel--this was of 25 +horse-power. The earliest Anzani engines were of the +three-cylinder fan type, one cylinder being vertical, and the +other two placed at an angle of 72 degrees on each side, as the +possibility of over-lubrication of the bottom cylinders was +feared if a regular radial construction were adopted. In order +to overcome the unequal balance of this type, balance weights +were fitted inside the crank case. + +The final development of this three-cylinder radial was the 'Y' +type of engine, in which the cylinders were regularly disposed +at 120 degrees apart, the bore was 4.1, stroke 4.7 inches, and +the power developed was 30 brake horse-power at 1,300 +revolutions per minute. + +Critchley's list of aero engines being constructed in 1910 shows +twelve of the radial type, with powers of between 14 and 100 +horse-power, and with from three to ten cylinder--this last is +probably the greatest number of cylinders that can be +successfully arranged in circular form. Of the twelve types of +1910, only two were water-cooled, and it is to be noted that +these two ran at the slowest speeds and had the lowest weight per +horse-power of any. + +The Anzani radial was considerably developed special attention +being paid to this type by its makers and by 1914 the Anzani +list comprised seven different sizes of air-cooled radials. Of +these the largest had twenty cylinders, developing 200 brake +horse-power--it was virtually a double radial--and the smallest +was the original 30 horse-power three-cylinder design. A +six-cylinder model was formed by a combination of two groups of +three cylinders each, acting upon a double-throw crankshaft; the +two crank pins were set at 180 degrees to each other, and the +cylinder groups were staggered by an amount equal to the +distance between the centres of the crank pins. Ten-cylinder +radial engines are made with two groups of five cylinders acting +upon two crank pins set at 180 degrees to each other, the largest +Anzani 'ten' developed 125 horsepower at 1,200 revolutions per +minute, the ten cylinders being each 4.5 inches in bore with +stroke of 5.9 inches, and the weight of the engine being 3.7 lbs. +per horse-power. In the 200 horse-power Anzani radial the +cylinders are arranged in four groups of five each, acting on two +crank pins. The bore of the cylinders in this engine is the same +as in the three-cylinder, but the stroke is increased to 5.5 +inches. The rated power is developed at 1,300 revolutions per +minute, and the engine complete weighs 3.4 lbs. per horse-power. + +With this 200 horse-power Anzani, a petrol consumption of as low +as 0.49 lbs. of fuel per brake horse-power per hour has been +obtained, but the consumption of lubricating oil is +compensatingly high, being up to one-fifth of the fuel used. The +cylinders are set desaxe with the crank shaft, and are of +cast-iron, provided with radiating ribs for air-cooling; they are +attached to the crank case by long bolts passing through bosses +at the top of the cylinders, and connected to other bolts at +right angles through the crank case. The tops of the cylinders +are formed flat, and seats for the inlet and exhaust valves are +formed on them. The pistons are cast-iron, fitted with ordinary +cast-iron spring rings. An aluminium crank case is used, being +made in two halves connected together by bolts, which latter also +attach the engine to the frame of the machine. The crankshaft +is of nickel steel, made hollow, and mounted on ball-bearings in +such a manner that practically a combination of ball and plain +bearings is obtained; the central web of the shaft is bent to +bring the centres of the crank pins as close together as +possible, leaving only room for the connecting rods, and the pins +are 180 degrees apart. Nickel steel valves of the cone-seated, +poppet type are fitted, the inlet valves being automatic, and +those for the exhaust cam-operated by means of push-rods. With +an engine having such a number of cylinders a very uniform +rotation of the crankshaft is obtained, and in actual running +there are always five of the cylinders giving impulses to the +crankshaft at the same time. + +An interesting type of pioneer radial engine was the Farcot, in +which the cylinders were arranged in a horizontal plane, with a +vertical crankshaft which operated the air-screw through bevel +gearing. This was an eight-cylinder engine, developing 64 +horse-power at 1,200 revolutions per minute. The R.E.P. type,in +the early days, was a 'fan' engine, but the designer, M. Robert +Pelterie, turned from this design to a seven-cylinder radial, +which at 1,100 revolutions per minute gave 95 horse-power. +Several makers entered into radial engine development in the +years immediately preceding the War, and in 1914 there were some +twenty-two different sizes and types, ranging from 30 to 600 +horse-power, being made, according to report; the actual +construction of the latter size at this time, however, is +doubtful. + +Probably the best example of radial construction up to the +outbreak of War was the Salmson (Canton-Unne) water-cooled, of +which in 1914 six sizes were listed as available. Of these +the smallest was a seven-cylinder 90 horse-power engine, and the +largest, rated at 600 horse-power, had eighteen cylinders. +These engines, during the War, were made under license by the +Dudbridge Ironworks in Great Britain. + +The accompanying diagram shows the construction of the cylinders +in the 200 horse-power size, showing the method of cooling, and +the arrangement of the connecting rods. A patent planetary gear, +also shown in the diagram, gives exactly the same stroke to all +the pistons. The complete engine has fourteen cylinders, of +forged steel machined all over, and so secured to the crank +case that any one can be removed without parting the crank case. +The water-jackets are of spun copper, brazed on to the cylinder, +and corrugated so as to admit of free expansion; the water is +circulated by means of a centrifugal pump. The pistons are of +cast-iron, each fitted with three rings, and the connecting rods +are of high grade steel, machined all over and fitted with +bushes of phosphor bronze; these rods are connected to a central +collar, carried on the crank pin by two ball-bearings. The +crankshaft has a single throw, and is made in two parts to allow +the cage for carrying the big end-pins of the connecting rods to +be placed in position. + +The casing is in two parts, on one of which the brackets for +fixing the engine are carried, while the other part carries the +valve-gear. Bolts secure the two parts together. The +mechanically-operated steel valves on the cylinders are each +fitted with double springs and the valves are operated by rods +and levers. Two Zenith carburettors are fitted on the rear half +of the crank case, and short induction pipes are led to each +cylinder; each of the carburettors is heated by the exhaust +gases. Ignition is by two high-tension magnetos, and a +compressed air self-starting arrangement is provided. Two oil +pumps are fitted for lubricating purposes, one of which forces +oil to the crankshaft and connecting-rod bearings, while the +second forces oil to the valve gear, the cylinders being so +arranged that the oil which flows along the walls cannot flood +the lower cylinders. This engine operates upon a six-stroke +cycle, a rather rare arrangement for internal combustion engines +of the electrical ignition type; this is done in order to obtain +equal angular intervals for the working impulses imparted to the +rotating crankshaft, as the cylinders are arranged in groups of +seven, and all act upon the one crankshaft. The angle, +therefore, between the impulses is 77 1/7 degrees. A diagram is +inset giving a side view of the engine, in order to show the +grouping of the cylinders. + +The 600 horse-power Salmson engine was designed with a view to +fitting to airships, and was in reality two nine-cylindered +engines, with a gear-box connecting them; double air-screws were +fitted, and these were so arranged that either or both of them +might be driven by either or both engines; in addition to this, +the two engines were complete and separate engines as regards +carburation and ignition, etc., so that they could be run +independently of each other. The cylinders were exceptionally +'long stroke,' being 5.9 inches bore to 8.27 inches stroke, and +the rated power was developed at 1,200 revolutions per minute, +the weight of the complete engine being only 4.1 lbs. per +horse-power at the normal rating. + +A type of engine specially devised for airship propulsion is +that in which the cylinders are arranged horizontally instead of +vertically, the main advantages of this form being the reduction +of head resistance and less obstruction to the view of the +pilot. A casing, mounted on the top of the engine, supports the +air-screw, which is driven through bevel gearing from the upper +end of the crankshaft. With this type of engine a better rate +of air-screw efficiency is obtained by gearing the screw down to +half the rate of revolution of the engine, this giving a more +even torque. The petrol consumption of the type is very low, +being only 0.48 lbs. per horse-power per hour, and equal +economy is claimed as regards lubricating oil, a consumption of +as little as 0.04 lbs. per horse-power per hour being claimed. + +Certain American radial engines were made previous to 1914, the +principal being the Albatross six-cylinder engines of 50 and 100 +horse-powers. Of these the smaller size was air-cooled, with +cylinders of 4.5 inches bore and 5 inches stroke, developing the +rated power at 1,230 revolutions per minute, with a weight of +about 5 lbs. per horse-power. The 100 horse-power size had +cylinders of 5.5 inches bore, developing its rated power at 1,230 +revolutions per minute, and weighing only 2.75 lbs. per +horse-power. This engine was markedly similar to the +six-cylindered Anzani, having all the valves mechanically +operated, and with auxiliary exhaust ports at the bottoms of the +cylinders, overrun by long pistons. These Albatross engines had +their cylinders arranged in two groups of three, with each group +of three pistons operating on one of two crank pins, each +180 degrees apart. + +The radial type of engine, thanks to Charles Manly, had the +honour of being first in the field as regards aero work. Its +many advantages, among which may be specially noted the very +short crankshaft as compared with vertical, Vee, or 'broad arrow' +type of engine, and consequent greater rigidity, ensure it +consideration by designers of to-day, and render it certain that +the type will endure. Enthusiasts claim that the 'broad arrow' +type, or Vee with a third row of cylinders inset between the +original two, is just as much a development from the radial +engine as from the vertical and resulting Vee; however this may +be, there is a place for the radial type in air-work for as long +as the internal combustion engine remains as a power plant. + + + +IV. THE ROTARY TYPE + +M. Laurent Seguin, the inventor of the Gnome rotary aero engine, +provided as great a stimulus to aviation as any that was given +anterior to the war period, and brought about a great advance in +mechanical flight, since these well-made engines gave a +high-power output for their weight, and were extremely smooth +in running. In the rotary design the crankshaft of the engine +is stationary, and the cylinders, crank case, and all their +adherent parts rotate; the working is thus exactly opposite in +principle to that of the radial type of aero engine, and the +advantage of the rotary lies in the considerable flywheel effect +produced by the revolving cylinders, with consequent evenness of +torque. Another advantage is that air-cooling, adopted in all +the Gnome engines, is rendered much more effective by the +rotation of the cylinders, though there is a tendency to +distortion through the leading side of each cylinder being more +efficiently cooled than the opposite side; advocates of other +types are prone to claim that the air resistance to the +revolving cylinders absorbs some 10 per cent of the power +developed by the rotary engine, but that has not prevented the +rotary from attaining to great popularity as a prime mover. + +There were, in the list of aero engines compiled in 1910, +five rotary engines included, all air-cooled. Three of these +were Gnome engines, and two of the make known as 'International.' +They ranged from 21.5 to 123 horse-power, the latter being rated +at only 1.8 lbs. weight per brake horse-power, and having +fourteen cylinders, 4.33 inches in diameter by 4.7 inches stroke. +By 1914 forty-three different sizes and types of rotary engine +were being constructed, and in 1913 five rotary type engines were +entered for the series of aeroplane engine trials held in +Germany. Minor defects ruled out four of these, and only the +German Bayerischer Motoren Flugzeugwerke completed the seven-hour +test prescribed for competing engines. Its large fuel +consumption barred this engine from the final trials, the +consumption being some 0.95 pints per horse-power per hour. The +consumption of lubricating oil, also was excessive, standing at +0.123 pint per horse-power per hour. The engine gave 37.5 +effective horse-power during its trial, and the loss due to air +resistance was 4.6 horse-power, about 11 per cent. The +accompanying drawing shows the construction of the engine, in +which the seven cylinders are arranged radially on the crank +case; the method of connecting the pistons to the crank pins can +be seen. The mixture is drawn through the crank chamber, and to +enter the cylinder it passes through the two automatic valves in +the crown of the piston; the exhaust valves are situated in the +tops of the cylinders, and are actuated by cams and push-rods. +Cooling of the cylinder is assisted by the radial rings, and the +diameter of these rings is increased round the hottest part of +the cylinder. When long flights are undertaken the advantage of +the light weight of this engine is more than counterbalanced by +its high fuel and lubricating oil consumption, but there are +other makes which are much better than this seven-cylinder German +in respect of this. + +Rotation of the cylinders in engines of this type is produced by +the side pressure of the pistons on the cylinder walls, and in +order to prevent this pressure from becoming abnormally large it +is necessary to keep the weight of the piston as low as possible, +as the pressure is produced by the tangential acceleration and +retardation of the piston. On the upward stroke the +circumferential velocity of the piston is rapidly increased, +which causes it to exert a considerable tangential pressure on +the side of the cylinder, and on the return stroke there is a +corresponding retarding effect due to the reduction of the +circumferential velocity of the piston. These side pressures +cause an appreciable increase in the temperatures of the +cylinders and pistons, which makes it necessary to keep the +power rating of the engines fairly low. + +Seguin designed his first Gnome rotary as a 34 horse-power +engine when run at a speed of 1,300 revolutions per minute. It +had five cylinders, and the weight was 3.9 lbs. per horse-power. +A seven-cylinder model soon displaced this first engine, and +this latter, with a total weight of 165 lbs., gave 61.5 +horse-power. The cylinders were machined out of solid nickel +chrome-steel ingots, and the machining was carried out so that +the cylinder walls were under 1/6 of an inch in thickness. The +pistons were cast-iron, fitted each with two rings, and the +automatic inlet valve to the cylinder was placed in the crown of +the piston. The connecting rods, of 'H' section, were of nickel +chrome-steel, and the large end of one rod, known as the +'master-rod' embraced the crank pin; on the end of this rod six +hollow steel pins were carried, and to these the remaining six +connecting-rods were attached. The crankshaft of the engine was +made of nickel chrome-steel, and was in two parts connected +together at the crank pin; these two parts, after the master-rod +had been placed in position and the other connecting rods had +been attached to it, were firmly secured. The steel crank case +was made in five parts, the two central ones holding the +cylinders in place, and on one side another of the five castings +formed a cam-box, to the outside of which was secured the +extension to which the air-screw was attached. On the other +side of the crank case another casting carried the thrust-box, +and the whole crank case, with its cylinders and gear, was +carried on the fixed crank shaft by means of four ball-bearings, +one of which also took the axial thrust of the air-screw. + +For these engines, castor oil is the lubricant usually adopted, +and it is pumped to the crankshaft by means of a gear-driven oil +pump; from this shaft the other parts of the engine are +lubricated by means of centrifugal force, and in actual practice +sufficient unburnt oil passes through the cylinders to lubricate +the exhaust valve, which partly accounts for the high rate of +consumption of lubricating oil. A very simple carburettor of +the float less, single-spray type was used, and the mixture was +passed along the hollow crankshaft to the interior of the crank +case, thence through the automatic inlet valves in the tops of +the pistons to the combustion chambers of the cylinders. +Ignition was by means of a high-tension magneto specially geared +to give the correct timing, and the working impulses occurred at +equal angular intervals of 102.85 degrees. The ignition was +timed so that the firing spark occurred when the cylinder was 26 +degrees before the position in which the piston was at the outer +end of its stroke, and this timing gave a maximum pressure in +the cylinder just after the piston had passed this position. + +By 1913, eight different sizes of the Gnome engine were being +constructed, ranging from 45 to 180 brake horse-power; four of +these were single-crank engines one having nine and the other +three having seven cylinders. The remaining four were +constructed with two cranks; three of them had fourteen +cylinders apiece, ranged in groups of seven, acting on the +cranks, and the one other had eighteen cylinders ranged in two +groups of nine, acting on its two cranks. Cylinders of the +two-crank engines are so arranged (in the fourteen-cylinder +type) that fourteen equal angular impulses occur during each +cycle; these engines are supported on bearings on both sides of +the engine, the air-screw being placed outside the front +support. In the eighteen-cylinder model the impulses occur at +each 40 degrees of angular rotation of the cylinders, securing +an extremely even rotation of the air-screw. + +In 1913 the Gnome Monosoupape engine was introduced, a model in +which the inlet valve to the cylinder was omitted, while the +piston was of the ordinary cast-iron type. A single exhaust +valve in the cylinder head was operated in a manner similar to +that on the previous Gnome engines, and the fact of this being +the only valve on the cylinder gave the engine its name. Each +cylinder contained ports at the bottom which communicated with +the crank chamber, and were overrun by the piston when this +was approaching the bottom end of its stroke. During the +working cycle of the engine the exhaust valve was opened early +to allow the exhaust gases to escape from the cylinder, so that +by the time the piston overran the ports at the bottom the +pressure within the cylinder was approximately equal to that in +the crank case, and practically no flow of gas took place in +either direction through the ports. The exhaust valve remained +open as usual during the succeeding up-stroke of the piston, and +the valve was held open until the piston had returned through +about one-third of its downward stroke, thus permitting fresh air +to enter the cylinder. The exhaust valve then closed, and the +downward motion of the piston, continuing, caused a partial +vacuum inside the cylinder; when the piston overran the ports, +the rich mixture from the crank case immediately entered. The +cylinder was then full of the mixture, and the next upward stroke +of the piston compressed the charge; upon ignition the working +cycle was repeated. The speed variation of this engine was +obtained by varying the extent and duration of the opening of the +exhaust valves, and was controlled by the pilot by hand-operated +levers acting on the valve tappet rollers. The weight per +horsepower of these engines was slightly less than that of the +two-valve type, while the lubrication of the gudgeon pin and +piston showed an improvement, so that a lower lubricating oil +consumption was obtained. The 100 horse-power Gnome Monosoupape +was built with nine cylinders, each 4.33 inches bore by 5.9 +inches stroke, and it developed its rated power at 1,200 +revolutions per minute. + +An engine of the rotary type, almost as well known as the Gnome, +is the Clerget, in which both cylinders and crank case are made +of steel, the former having the usual radial fins for cooling. +In this type the inlet and exhaust valves are both located in +the cylinder head, and mechanically operated by push-rods and +rockers. Pipes are carried from the crank case to the inlet +valve casings to convey the mixture to the cylinders, a +carburettor of the central needle type being used. The +carburetted mixture is taken into the crank case chamber in a +manner similar to that of the Gnome engine. Pistons of +aluminium alloy, with three cast-iron rings, are fitted, the top +ring being of the obturator type. The large end of one of the +nine connecting rods embraces the crank pin and the pressure is +taken on two ball-bearings housed in the end of the rod. This +carries eight pins, to which the other rods are attached, and the +main rod being rigid between the crank pin and piston pin +determines the position of the pistons. Hollow connecting-rods +are used, and the lubricating oil for the piston pins passes from +the crankshaft through the centres of the rods. Inlet and +exhaust valves can be set quite independently of one another--a +useful point, since the correct timing of the opening of these +valves is of importance. The inlet valve opens 4 degrees from +top centre and closes after the bottom dead centre of the piston; +the exhaust valve opens 68 degrees before the bottom centre and +closes 4 degrees after the top dead centre of the piston. The +magnetos are set to give the spark in the cylinder at 25 degrees +before the end of the compression stroke--two high-tension +magnetos are used: if desired, the second one can be adjusted to +give a later spark for assisting the starting of the engine. The +lubricating oil pump is of the valveless two-plunger type, so +geared that it runs at seven revolutions to 100 revolutions of +the engine; by counting the pulsations the speed of the engine +can be quickly calculated by multiplying the pulsations by 100 +and dividing by seven. In the 115 horse-power nine-cylinder +Clerget the cylinders are 4.7 bore with a 6.3 inches stroke, and +the rated power of the engine is obtained at 1,200 revolutions +per minute. The petrol consumption is 0.75 pint per horse-power +per hour. + +A third rotary aero engine, equally well known with the +foregoing two, is the Le Rhone, made in four different sizes +with power outputs of from 50 to 160 horse-power; the two +smaller sizes are single crank engines with seven and nine +cylinders respectively, and the larger sizes are of double-crank +design, being merely the two smaller sizes doubled--fourteen and +eighteen-cylinder engines. The inlet and exhaust valves are +located in the cylinder head, and both valves are mechanically +operated by one push-rod and rocker, radial pipes from crank +case to inlet valve casing taking the mixture to the cylinders. +The exhaust valves are placed on the leading, or air-screw side, +of the engine, in order to get the fullest possible cooling +effect. The rated power of each type of engine is obtained at +1,200 revolutions per minute, and for all four sizes the +cylinder bore is 4.13 inches, with a 5.5 inches piston stroke. +Thin cast-iron liners are shrunk into the steel cylinders in +order to reduce the amount of piston friction. Although the Le +Rhone engines are constructed practically throughout of steel, +the weight is only 2.9 lbs. per horse-power in the +eighteen-cylinder type. + +American enterprise in the construction of the rotary type is +perhaps best illustrated in the 'Gyro 'engine; this was first +constructed with inlet valves in the heads of the pistons, after +the Gnome pattern, the exhaust valves being in the heads of the +cylinders. The inlet valve in the crown of each piston was +mechanically operated in a very ingenious manner by the +oscillation of the connecting-rod. The Gyro-Duplex engine +superseded this original design, and a small cross-section +illustration of this is appended. It is constructed in seven and +nine-cylinder sizes, with a power range of from 50 to 100 +horse-power; with the largest size the low weight of 2.5 lbs.. +per horse-power is reached. The design is of considerable +interest to the internal combustion engineer, for it embodies a +piston valve for controlling auxiliary exhaust ports, which also +acts as the inlet valve to the cylinder. The piston uncovers the +auxiliary ports when it reaches the bottom of its stroke, and at +the end of the power stroke the piston is in such a position that +the exhaust can escape over the top of it. The exhaust valve in +the cylinder head is then opened by means of the push-rod and +rocker, and is held open until the piston has completed its +upward stroke and returned through more than half its subsequent +return stroke. When the exhaust valve closes, the cylinder has a +charge of fresh air, drawn in through the exhaust valve, and the +further motion of the piston causes a partial vacuum; by the time +the piston reaches bottom dead centre the piston-valve has moved +up to give communication between the cylinder and the crank case, +therefore the mixture is drawn into the cylinder. Both the +piston valve and exhaust valve are operated by cams formed on the +one casting, which rotates at seven-eighths engine speed for the +seven-cylinder type, and nine-tenths engine speed for the +nine-cylinder engines. Each of these cams has four or five +points respectively, to suit the number of cylinders. + +The steel cylinders are machined from solid forgings and +provided with webs for air-cooling as shown. Cast-iron pistons +are used, and are connected to the crankshaft in the same manner +as with the Gnome and Le Rhone engines. Petrol is sprayed into +the crank case by a small geared pump and the mixture is taken +from there to the piston valves by radial pipes. Two separate +pumps are used for lubrication, one forcing oil to the crank-pin +bearing and the other spraying the cylinders. + +Among other designs of rotary aero engines the E.J.C. is +noteworthy, in that the cylinders and crank case of this engine +rotate in opposite directions, and two air-screws are used, one +being attached to the end of the crankshaft, and the other to the +crank case. Another interesting type is the Burlat rotary, in +which both the cylinders and crankshaft rotate in the same +direction, the rotation of the crankshaft being twice that of the +cylinders as regards speed. This engine is arranged to work on +the four-stroke cycle with the crankshaft making four, and the +cylinders two, revolutions per cycle. + +It would appear that the rotary type of engine is capable of but +little more improvement--save for such devices as these of the +last two engines mentioned, there is little that Laurent Seguin +has not already done in the Gnome type. The limitation of the +rotary lies in its high fuel and lubricating oil consumption, +which renders it unsuited for long-distance aero work; it was, +in the war period, an admirable engine for such short runs as +might be involved in patrol work 'over the lines,' and for +similar purposes, but the watercooled Vee or even vertical, with +its much lower fuel consumption, was and is to be preferred for +distance work. The rotary air-cooled type has its uses, and for +them it will probably remain among the range of current types +for some time to come. Experience of matters aeronautical is +sufficient to show, however, that prophecy in any direction is +most unsafe. + + + +V. THE HORIZONTALLY-OPPOSED ENGINE + +Among the first internal combustion engines to be taken into use +with aircraft were those of the horizontally-opposed four-stroke +cycle type, and, in every case in which these engines were used, +their excellent balance and extremely even torque rendered them +ideal-until the tremendous increase in power requirements +rendered the type too long and bulky for placing in the fuselage +of an aeroplane. As power increased, there came a tendency +toward placing cylinders radially round a central crankshaft, +and, as in the case of the early Anzani, it may be said that the +radial engine grew out of the horizontal opposed piston type. +There were, in 1910--that is, in the early days of small power +units, ten different sizes of the horizontally opposed engine +listed for manufacture, but increase in power requirements +practically ruled out the type for air work. + +The Darracq firm were the leading makers of these engines in +1910; their smallest size was a 24 horsepower engine, with two +cylinders each of 5.1 inches bore by 4.7 inches stroke. This +engine developed its rated power at 1,500 revolutions per +minute, and worked out at a weight of 5 lbs. per horse-power. +With these engines the cranks are so placed that two regular +impulses are given to the crankshaft for each cycle of working, +an arrangement which permits of very even balancing of the +inertia forces of the engine. The Darracq firm also made a +four-cylindered horizontal opposed piston engine, in which two +revolutions were given to the crankshaft per revolution, at +equal angular intervals. + +The Dutheil-Chambers was another engine of this type, and had +the distinction of being the second largest constructed. At +1,000 revolutions per minute it developed 97 horse-power; its +four cylinders were each of 4.93 inches bore by 11.8 inches +stroke--an abnormally long stroke in comparison with the bore. +The weight--which owing to the build of the engine and its length +of stroke was bound to be rather high, actually amounted to 8.2 +lbs. per horse-power. Water cooling was adopted, and the engine +was, like the Darracq four-cylinder type, so arranged as to give +two impulses per revolution at equal angular intervals of +crankshaft rotation. + +One of the first engines of this type to be constructed in +England was the Alvaston, a water-cooled model which was made in +20, 30, and 50 brake horse-power sizes, the largest being a +four-cylinder engine. All three sizes were constructed to run +at 1,200 revolutions per minute. In this make the cylinders +were secured to the crank case by means of four long tie bolts +passing through bridge pieces arranged across the cylinder +heads, thus relieving the cylinder walls of all longitudinal +explosion stresses. These bridge pieces were formed from chrome +vanadium steel and milled to an 'H' section, and the bearings +for the valve-tappet were forged solid with them. Special +attention was given to the machining of the interiors of the +cylinders and the combustion heads, with the result that the +exceptionally high compression of 95 lbs. per square inch was +obtained, giving a very flexible engine. The cylinder heads +were completely water-jacketed, and copper water-jackets were +also fitted round the cylinders. The mechanically operated +valves were actuated by specially shaped cams, and were so +arranged that only two cams were required for the set of eight +valves. The inlet valves at both ends of the engine were +connected by a single feed-pipe to which the carburettor was +attached, the induction piping being arranged above the engine +in an easily accessible position. Auxiliary air ports were +provided in the cylinder walls so that the pistons overran them +at the end of their stroke. A single vertical shaft running in +ball-bearings operated the valves and water circulating pump, +being driven by spiral gearing from the crankshaft at half +speed. In addition to the excellent balance obtained with this +engine, the makers claimed with justice that the number of +working parts was reduced to an absolute minimum. + +In the two-cylinder Darracq, the steel cylinders were machined +from solid, and auxiliary exhaust ports, overrun by the piston +at the inner end of its stroke, were provided in the cylinder +walls, consisting of a circular row of drilled holes--this +arrangement was subsequently adopted on some of the Darracq +racing car engines. The water jackets were of copper, soldered +to the cylinder walls; both the inlet and exhaust valves were +located in the cylinder heads, being operated by rockers and +push-rods actuated by cams on the halftime shaft driven from one +end of the crankshaft. Ignition was by means of a high-tension +magneto, and long induction pipes connected the-ends of the +cylinders to the carburettor, the latter being placed underneath +the engine. Lubrication was effected by spraying oil into the +crank case by means of a pump, and a second pump circulated the +cooling water. + +Another good example of this type of engine was the Eole, which +had eight opposed pistons, each pair of which was actuated by a +common combustion chamber at the centre of the engine, two +crankshafts being placed at the outer ends of the engine. This +reversal of the ordinary arrangement had two advantages; it +simplified induction, and further obviated the need for cylinder +heads, since the explosion drove at two piston heads instead of +at one piston head and the top of the cylinder; against this, +however, the engine had to be constructed strongly enough to +withstand the longitudinal stresses due to the explosions, as +the cranks are placed on the outer ends and the cylinders and +crank-cases take the full force of each explosion. Each +crankshaft drove a separate air-screw. + +This pattern of engine was taken up by the Dutheil-Chambers firm +in the pioneer days of aircraft, when the firm in question +produced seven different sizes of horizontal engines. The +Demoiselle monoplane used by Santos-Dumont in 1909 was fitted +with a two-cylinder, horizontally-opposed Dutheil-Chambers +engine, which developed 25 brake horse-power at a speed of +1,100 revolutions per minute, the cylinders being of 5 inches +bore by 5.1 inches stroke, and the total weight of the engine +being some 120 lbs. The crankshafts of these engines were +usually fitted with steel flywheels in order to give a very even +torque, the wheels being specially constructed with wire spokes. +In all the Dutheil-Chambers engines water cooling was adopted, +and the cylinders were attached to the crank cases by means of +long bolts passing through the combustion heads. + +For their earliest machines, the Clement-Bayard firm constructed +horizontal engines of the opposed piston type. The best known of +these was the 30 horse-power size, which had cylinders of 4.7 +inches diameter by 5.1 inches stroke, and gave its rated power +at 1,200 revolutions per minute. In this engine the steel +cylinders were secured to the crank case by flanges, and +radiating ribs were formed around the barrel to assist the +air-cooling. Inlet and exhaust valves were actuated by +push-rods and rockers actuated from the second motion shaft +mounted above the crank case; this shaft also drove the +high-tension magneto with which the engine was fitted. A ring +of holes drilled round each cylinder constituted auxiliary ports +which the piston uncovered at the inner end of its stroke, and +these were of considerable assistance not only in expelling +exhaust gases, but also in moderating the temperature of the +cylinder and of the main exhaust valve fitted in the cylinder +head. A water-cooled Clement-Bayard horizontal engine was also +made, and in this the auxiliary exhaust ports were not embodied; +except in this particular, the engine was very similar to the +water-cooled Darracq. + +The American Ashmusen horizontal engine, developing 100 +horse-power, is probably the largest example of this type +constructed. It was made with six cylinders arranged on each +side of a common crank case, with long bolts passing through the +cylinder heads to assist in holding them down. The induction +piping and valve-operating gear were arranged below the engine, +and the half-speed shaft carried the air-screw. + +Messrs Palons and Beuse, Germans, constructed a light-weight, +air-cooled, horizontally-opposed engine, two-cylindered. In +this the cast-iron cylinders were made very thin, and were +secured to the crank case by bolts passing through lugs cast on +the outer ends of the cylinders; the crankshaft was made hollow, +and holes were drilled through the webs of the connecting-rods +in order to reduce the weight. The valves were fitted to the +cylinder heads, the inlet valves being of the automatic type, +while the exhaust valves were mechanically operated from the +cam-shaft by means of rockers and push-rods. Two carburettors +were fitted, to reduce the induction piping to a minimum; one +was attached to each combustion chamber, and ignition was by the +normal high-tension magneto driven from the halftime shaft. + +There was also a Nieuport two-cylinder air-cooled horizontal +engine, developing 35 horse-power when running at 1,300 +revolutions per minute, and being built at a weight of 5.1 lbs. +per horse-power. The cylinders were of 5.3 inches diameter by +5.9 inches stroke; the engine followed the lines of the Darracq +and Dutheil-Chambers pretty closely, and thus calls for no +special description. + +The French Kolb-Danvin engine of the horizontal type, first +constructed in 1905, was probably the first two-stroke cycle +engine designed to be applied to the propulsion of aircraft; it +never got beyond the experimental stage, although its trials +gave very good results. Stepped pistons were adopted, and the +charging pump at one end was used to scavenge the power cylinder +at the other ends of the engine, the transfer ports being formed +in the main casting. The openings of these ports were +controlled at both ends by the pistons, and the location of the +ports appears to have made it necessary to take the exhaust from +the bottom of one cylinder and from the top of the other. The +carburetted mixture was drawn into the scavenging cylinders, and +the usual deflectors were cast on the piston heads to assist in +the scavenging and to prevent the fresh gas from passing out of +the exhaust ports. + + + +VI. THE TWO-STROKE CYCLE ENGINE + +Although it has been little used for aircraft propulsion, the +possibilities of the two-stroke cycle engine render some study +of it desirable in this brief review of the various types of +internal combustion engine applicable both to aeroplanes and +airships. Theoretically the two-stroke cycle engine--or as it +is more commonly termed, the 'two-stroke,' is the ideal power +producer; the doubling of impulses per revolution of the +crankshaft should render it of very much more even torque than +the four-stroke cycle types, while, theoretically, there should +be a considerable saving of fuel, owing to the doubling of the +number of power strokes per total of piston strokes. In +practice, however, the inefficient scavenging of virtually every +two-stroke cycle engine produced nullifies or more than +nullifies its advantages over the four-stroke cycle engine; in +many types, too, there is a waste of fuel gases through the +exhaust ports, and much has yet to be done in the way of +experiment and resulting design before the two-stroke cycle +engine can be regarded as equally reliable, economical, and +powerful with its elder brother. + +The first commercially successful engine operating on the +two-stroke cycle was invented by Mr Dugald Clerk, who in 1881 +proved the design feasible. As is more or less generally +understood, the exhaust gases of this engine are discharged from +the cylinder during the time that the piston is passing the +inner dead centre, and the compression, combustion, and +expansion of the charge take place in similar manner to that of +the four-stroke cycle engine. The exhaust period is usually +controlled by the piston overrunning ports in the cylinder at +the end of its working stroke, these ports communicating direct +with the outer air--the complication of an exhaust valve is thus +obviated; immediately after the escape of the exhaust gases, +charging of the cylinder occurs, and the fresh gas may be +introduced either through a valve in the cylinder head or +through ports situated diametrically opposite to the exhaust +ports. The continuation of the outward stroke of the piston, +after the exhaust ports have been closed, compresses the charge +into the combustion chamber of the cylinder, and the ignition of +the mixture produces a recurrence of the working stroke. + +Thus, theoretically, is obtained the maximum of energy with the +minimum of expenditure; in practice, however, the scavenging of +the power cylinder, a matter of great importance in all internal +combustion engines, is often imperfect, owing to the opening of +the exhaust ports being of relatively short duration; clearing +the exhaust gases out of the cylinder is not fully accomplished, +and these gases mix with the fresh charge and detract from its +efficiency. Similarly, owing to the shorter space of time +allowed, the charging of the cylinder with the fresh mixture is +not so efficient as in the four-stroke cycle type; the fresh +charge is usually compressed slightly in a separate +chamber--crank case, independent cylinder, or charging pump, and +is delivered to the working cylinder during the beginning of the +return stroke of the piston, while in engines working on the +four-stroke cycle principle a complete stroke is devoted to the +expulsion of the waste gases of the exhaust, and another full +stroke to recharging the cylinder with fresh explosive mixture. + +Theoretically the two-stroke and the four-stroke cycle engines +possess exactly the same thermal efficiency, but actually this +is modified by a series of practical conditions which to some +extent tend to neutralise the very strong case in favour of the +two-stroke cycle engine. The specific capacity of the engine +operating on the two-stroke principle is theoretically twice +that of one operating on the four-stroke cycle, and +consequently, for equal power, the former should require only +about half the cylinder volume of the latter; and, owing to the +greater superficial area of the smaller cylinder, relatively, +the latter should be far more easily cooled than the larger +four-stroke cycle cylinder; thus it should be possible to get +higher compression pressures, which in turn should result in +great economy of working. Also the obtaining of a working +impulse in the cylinder for each revolution of the crankshaft +should give a great advantage in regularity of rotation--which +it undoubtedly does--and the elimination of the operating gear +for the valves, inlet and exhaust, should give greater +simplicity of design. + +In spite of all these theoretical--and some practical--advantages +the four-stroke cycle engine was universally adopted for aircraft +work; owing to the practical equality of the two principles of +operation, so far as thermal efficiency and friction losses are +concerned, there is no doubt that the simplicity of design (in +theory) and high power output to weight ratio (also in theory) +ought to have given the 'two-stroke' a place on the aeroplane. +But this engine has to be developed so as to overcome its +inherent drawbacks; better scavenging methods have yet to be +devised--for this is the principal drawback--before the +two-stroke can come to its own as a prime mover for aircraft. + +Mr Dugald Clerk's original two-stroke cycle engine is indicated +roughly, as regards principle, by the accompanying diagram, from +which it will be seen that the elimination of the ordinary inlet +and exhaust valves of the four-stroke type is more than +compensated by a separate cylinder which, having a piston worked +from the connecting-rod of the power cylinder, was used to +charging, drawing the mixture from the carburettor past the +valve in the top of the charging cylinder, and then forcing it +through the connecting pipe into the power cylinder. The inlet +valves both on the charging and the power cylinders are +automatic; when the power piston is near the bottom of its +stroke the piston in the charging cylinder is compressing the +carburetted air, so that as soon as the pressure within the +power cylinder is relieved by the exit of the burnt gases +through the exhaust ports the pressure in the charging cylinder +causes the valve in the head of the power cylinder to open, and +fresh mixture flows into the cylinder, replacing the exhaust +gases. After the piston has again covered the exhaust ports the +mixture begins to be compressed, thus automatically closing the +inlet valve. Ignition occurs near the end of the compression +stroke, and the working stroke immediately follows, thus giving +an impulse to the crankshaft on every down stroke of the piston. +If the scavenging of the cylinder were complete, and the cylinder +were to receive a full charge of fresh mixture for every stroke, +the same mean effective pressure as is obtained with four-stroke +cycle engines ought to be realised, and at an equal speed of +rotation this engine should give twice the power obtainable from +a four-stroke cycle engine of equal dimensions. This result was +not achieved, and, with the improvements in construction brought +about by experiment up to 1912, the output was found to be only +about fifty per cent more than that of a four-stroke cycle engine +of the same size, so that, when the charging cylinder is +included, this engine has a greater weight per horse-power, while +the lowest rate of fuel consumption recorded was 0.68 lb. per +horse-power per hour. + +In 1891 Mr Day invented a two-stroke cycle engine which used the +crank case as a scavenging chamber, and a very large number of +these engines have been built for industrial purposes. The +charge of carburetted air is drawn through a non-return valve +into the crank chamber during the upstroke of the piston, and +compressed to about 4 lbs. pressure per square inch on the +down stroke. When the piston approaches the bottom end of its +stroke the upper edge first overruns an exhaust port, and almost +immediately after uncovers an inlet port on the opposite side of +the cylinder and in communication with the crank chamber; the +entering charge, being under pressure, assists in expelling the +exhaust gases from the cylinder. On the next upstroke the +charge is compressed into the combustion space of the cylinder, +a further charge simultaneously entering the crank case to be +compressed after the ignition for the working stroke. To +prevent the incoming charge escaping through the exhaust ports +of the cylinder a deflector is formed on the top of the piston, +causing the fresh gas to travel in an upward direction, thus +avoiding as far as possible escape of the mixture to the +atmosphere. From experiments conducted in 1910 by Professor +Watson and Mr Fleming it was found that the proportion of fresh +gases which escaped unburnt through the exhaust ports diminished +with increase of speed; at 600 revolutions per minute about 36 +per cent of the fresh charge was lost; at 1,200 revolutions per +minute this was reduced to 20 per cent, and at 1,500 revolutions +it was still farther reduced to 6 per cent. + +So much for the early designs. With regard to engines of this +type specially constructed for use with aircraft, three designs +call for special mention. Messrs A. Gobe and H. Diard, Parisian +engineers, produced an eight-cylindered two-stroke cycle engine +of rotary design, the cylinders being co-axial. Each pair of +opposite pistons was secured together by a rigid connecting rod, +connected to a pin on a rotating crankshaft which was mounted +eccentrically to the axis of rotation of the cylinders. The +crankshaft carried a pinion gearing with an internally toothed +wheel on the transmission shaft which carried the air-screw. The +combustible mixture, emanating from a common supply pipe, was led +through conduits to the front ends of the cylinders, in which the +charges were compressed before being transferred to the working +spaces through ports in tubular extensions carried by the +pistons. These extensions had also exhaust ports, registering +with ports in the cylinder which communicated with the outer air, +and the extensions slid over depending cylinder heads attached to +the crank case by long studs. The pump charge was compressed in +one end of each cylinder, and the pump spaces each delivered +into their corresponding adjacent combustion spaces. The charges +entered the pump spaces during the suction period through +passages which communicated with a central stationary supply +passage at one end of the crank case, communication being cut off +when the inlet orifice to the passage passed out of register with +the port in the stationary member. The exhaust ports at the +outer end of the combustion space opened just before and closed a +little later than the air ports, and the incoming charge assisted +in expelling the exhaust gases in a manner similar to that of the +earlier types of two-stroke cycle engine; The accompanying rough +diagram assists in showing the working of this engine. + +Exhibited in the Paris Aero Exhibition of 1912, the Laviator +two-stroke cycle engine, six-cylindered, could be operated either +as a radial or as a rotary engine, all its pistons acting on a +single crank. Cylinder dimensions of this engine were 3.94 +inches bore by 5.12 inches stroke, and a power output of 50 +horse-power was obtained when working at a rate of 1,200 +revolutions per minute. Used as a radial engine, it developed +65 horse-power at the same rate of revolution, and, as the total +weight was about 198 lbs., the weight of about 3 lbs. per +horse-power was attained in radial use. Stepped pistons were +employed, the annular space between the smaller or power piston +and the walls of the larger cylinder being used as a charging +pump for the power cylinder situated 120 degrees in rear of it. +The charging cylinders were connected by short pipes to ports in +the crank case which communicated with the hollow crankshaft +through which the fresh gas was supplied, and once in each +revolution each port in the case registered with the port in the +hollow shaft. The mixture which then entered the charging +cylinder was transferred to the corresponding working +cylinder when the piston of that cylinder had reached the end of +its power stroke, and immediately before this the exhaust ports +diametrically opposite the inlet ports were uncovered; scavenging +was thus assisted in the usual way. The very desirable feature +of being entirely valveless was accomplished with this engine, +which is also noteworthy for exceedingly compact design. + +The Lamplough six-cylinder two-stroke cycle rotary, shown at the +Aero Exhibition at Olympia in 1911, had several innovations, +including a charging pump of rotary blower type. With the six +cylinders, six power impulses at regular intervals were given on +each rotation; otherwise, the cycle of operations was carried +out much as in other two-stroke cycle engines. The pump +supplied the mixture under slight pressure to an inlet port in +each cylinder, which was opened at the same time as the exhaust +port, the period of opening being controlled by the piston. The +rotary blower sucked the mixture from the carburettor and +delivered it to a passage communicating with the inlet ports in +the cylinder walls. A mechanically-operated exhaust valve was +placed in the centre of each cylinder head, and towards the end +of the working stroke this valve opened, allowing part of the +burnt gases to escape to the atmosphere; the remainder was +pushed out by the fresh mixture going in through the ports at +the bottom end of the cylinder. In practice, one or other of +the cylinders was always taking fresh mixture while working, +therefore the delivery from the pump was continuous and the +mixture had not to be stored under pressure. + +The piston of this engine was long enough to keep the ports +covered when it was at the top of the stroke, and a bottom ring +was provided to prevent the mixture from entering the crank +case. In addition to preventing leakage, this ring no doubt +prevented an excess of oil working up the piston into the +cylinder. As the cylinder fired with every revolution, the +valve gear was of the simplest construction, a fixed cam lifting +each valve as the cylinder came into position. The spring of +the exhaust valve was not placed round the stem in the usual +way, but at the end of a short lever, away from the heat of the +exhaust gases. The cylinders were of cast steel, the crank case +of aluminium, and ball-bearings were fitted to the crankshaft, +crank pins, and the rotary blower pump. Ignition was by means +of a high-tension magneto of the two-spark pattern, and with a +total weight of 300 lbs. the maximum output was 102 brake +horse-power, giving a weight of just under 3 lbs. per +horse-power. + +One of the most successful of the two-stroke cycle engines was +that designed by Mr G. F. Mort and constructed by the New +Engine Company. With four cylinders of 3.69 inches bore by 4.5 +inches stroke, and running at 1,250 revolutions per minute, this +engine developed 50 brake horse-power; the total weight of the +engine was 155 lbs., thus giving a weight of 3.1 lbs. per +horse-power. A scavenging pump of the rotary type was employed, +driven by means of gearing from the engine crankshaft, and in +order to reduce weight to a minimum the vanes were of aluminium. +This engine was tried on a biplane, and gave very satisfactory +results. + +American design yields two apparently successful two-stroke +cycle aero engines. A rotary called the Fredericson engine was +said to give an output of 70 brake horse-power with five +cylinders 4.5 inches diameter by 4.75 inches stroke, running +at 1,000 revolutions per minute. Another, the Roberts +two-stroke cycle engine, yielded 100 brake horse-power from six +cylinders of the stepped piston design; two carburettors, each +supplying three cylinders, were fitted to this engine. Ignition +was by means of the usual high-tension magneto, gear-driven from +the crankshaft, and the engine, which was water-cooled, was of +compact design. + +It may thus be seen that the two-stroke cycle type got as far as +actual experiment in air work, and that with considerable +success. So far, however, the greater reliability of the +four-stroke cycle has rendered it practically the only aircraft +engine, and the two-stroke has yet some way to travel before it +becomes a formidable competitor, in spite of its admitted +theoretical and questioned practical advantages. + + + +VII. ENGINES OF THE WAR PERIOD + +The principal engines of British, French, and American design +used in the war period and since are briefly described under the +four distinct types of aero engine; such notable examples as the +Rolls-Royce, Sunbeam, and Napier engines have been given special +mention, as they embodied--and still embody--all that is best in +aero engine practice. So far, however, little has been said +about the development of German aero engine design, apart from +the early Daimler and other pioneer makes. + +At the outbreak of hostilities in 1914, thanks to subsidies to +contractors and prizes to aircraft pilots, the German aeroplane +industry was in a comparatively flourishing condition. There +were about twenty-two establishments making different types of +heavier-thanair machines, monoplane and biplane, engined for the +most part with the four-cylinder Argus or the six-cylinder +Mercedes vertical type engines, each of these being of 100 +horse-power--it was not till war brought increasing demands on +aircraft that the limit of power began to rise. Contemporary +with the Argus and Mercedes were the Austro-Daimler, Benz, and +N.A.G., in vertical design, while as far as rotary types were +concerned there were two, the Oberursel and the Stahlhertz; of +these the former was by far the most promising, and it came to +virtual monopoly of the rotary-engined plane as soon as the war +demand began. It was practically a copy of the famous Gnome +rotary, and thus deserves little description. + +Germany, from the outbreak of war, practically, concentrated on +the development of the Mercedes engine; and it is noteworthy +that, with one exception, increase of power corresponding with +the increased demand for power was attained without increasing +the number of cylinders. The various models ranged between 75 +and 260 horse-power, the latter being the most recent production +of this type. The exception to the rule was the eight-cylinder +240 horse-power, which was replaced by the 260 horse-power +six-cylinder model, the latter being more reliable and but very +slightly heavier. Of the other engines, the 120 horsepower +Argus and the 160 and 225 horse-power Benz were the most used, +the Oberursel being very largely discarded after the Fokker +monoplane had had its day, and the N.A.G. and Austro-Daimler +Daimler also falling to comparative disuse. It may be said that +the development of the Mercedes engine contributed very largely +to such success as was achieved in the war period by German +aircraft, and, in developing the engine, the builders were +careful to make alterations in such a way as to effect the least +possible change in the design of aeroplane to which they were to +be fitted. Thus the engine base of the 175 horse-power model +coincided precisely with that of the 150 horse-power model, and +the 200 and 240 horse-power models retained the same base +dimensions. It was estimated, in 1918, that well over eighty +per cent of German aircraft was engined with the Mercedes type. + +In design and construction, there was nothing abnormal about the +Mercedes engine, the keynote throughout being extreme +reliability and such simplification of design as would permit of +mass production in different factories. Even before the war, +the long list of records set up by this engine formed practical +application of the wisdom of this policy; Bohn's flight of 24 +hours 10 minutes, accomplished on July 10th and 11th, 1914, +9is an instance of this--the flight was accomplished on an +Albatross biplane with a 75 horsepower Mercedes engine. The +radial type, instanced in other countries by the Salmson and +Anzani makes, was not developed in Germany; two radial engines +were made in that country before the war, but the Germans seemed +to lose faith in the type under war conditions, or it may have +been that insistence on standardisation ruled out all but the +proved examples of engine. + +Details of one of the middle sizes of Mercedes motor, the 176 +horse-power type, apply very generally to the whole range; this +size was in use up to and beyond the conclusion of hostilities, +and it may still be regarded as characteristic of modern (1920) +German practice. The engine is of the fixed vertical type, +has six cylinders in line, not off-set, and is water-cooled. +The cam shaft is carried in a special bronze casing, seated on +the immediate top of the cylinders, and a vertical shaft is +interposed between crankshaft and camshaft, the latter being +driven by bevel gearing. + +On this vertical connecting-shaft the water pump is located, +serving to steady the motion of the shaft. Extending immediately +below the camshaft is another vertical shaft, driven by bevel +gears from the crank-shaft, and terminating in a worm which +drives the multiple piston oil pumps. + +The cylinders are made from steel forgings, as are the valve +chamber elbows, which are machined all over and welded together. +A jacket of light steel is welded over the valve elbows and +attached to a flange on the cylinders, forming a water-cooling +space with a section of about 7/16 of an inch. The cylinder +bore is 5.5 inches, and the stroke 6.29 inches. The cylinders +are attached to the crank case by means of dogs and long through +bolts, which have shoulders near their lower ends and are bolted +to the lower half of the crank chamber. A very light and rigid +structure is thus obtained, and the method of construction won +the flattery of imitation by makers of other nationality. + +The cooling system for the cylinders is extremely efficient. +After leaving the water pump, the water enters the top of the +front cylinders and passes successively through each of the six +cylinders of the row; short tubes, welded to the tops of the +cylinders, serve as connecting links in the system. The Panhard +car engines for years were fitted with a similar cooling system, +and the White and Poppe lorry engines were also similarly +fitted; the system gives excellent cooling effect where it is +most needed, round the valve chambers and the cylinder heads. + +The pistons are built up from two pieces; a dropped forged steel +piston head, from which depend the piston pin bosses, is +combined with a cast-iron skirt, into which the steel head is +screwed. Four rings are fitted, three at the upper and one at +the lower end of the piston skirt, and two lubricating oil +grooves are cut in the skirt, in addition to the ring grooves. +Two small rivets retain the steel head on the piston skirt after +it has been screwed into position, and it is also welded at two +points. The coefficient of friction between the cast-iron and +steel is considerably less than that which would exist between +two steel parts, and there is less tendency for the skirt to +score the cylinder walls than would be the case if all steel were +used--so noticeable is this that many makers, after giving steel +pistons a trial, discarded them in favour of cast-iron; the Gnome +is an example of this, being originally fitted with a steel +piston carrying a brass ring, discarded in favour of a cast-iron +piston with a percentage of steel in the metal mixture. In the +Le Rhone engine the difficulty is overcome by a cast-iron liner +to the cylinders. + +The piston pin of the Mercedes is of chrome nickel steel, and is +retained in the piston by means of a set screw and cotter pin. +The connecting rods, of I section, are very short and rigid, +carrying floating bronze bushes which fit the piston pins at the +small end, and carrying an oil tube on each for conveying oil +from the crank pin to the piston pin. + +The crankshaft is of chrome nickel steel, carried on seven +bearings. Holes are drilled through each of the crank pins and +main bearings, for half the diameter of the shaft, and these are +plugged with pressed brass studs. Small holes, drilled through +the crank cheeks, serve to convey lubricant from the main +bearings to the crank pins. The propeller thrust is taken by a +simple ball thrust bearing at the propeller end of the +crankshaft, this thrust bearing being seated in a steel retainer +which is clamped between the two halves of the crank case. At +the forward end of the crankshaft there is mounted a master +bevel gear on six splines; this bevel floats on the splines +against a ball thrust bearing, and, in turn, the thrust is taken +by the crank case cover. A stuffing box prevents the loss of +lubricant out of the front end of the crank chamber, and an oil +thrower ring serves a similar purpose at the propeller end of the +crank chamber. + +With a motor speed of 1,450 r.p.m., the vertical shaft at the +forward end of the motor turns at 2,175 r.p.m., this being the +speed of the two magnetos and the water pump. The lower +vertical shaft bevel gear and the magneto driving gear are made +integral with the vertical driving shaft, which is carried in +plain bearings in an aluminium housing. This housing is clamped +to the upper half of the crank case by means of three studs. +The cam-shaft carries eighteen cams, these being the inlet and +exhaust cams, and a set of half compression cams which are +formed with the exhaust cams and are put into action when +required by means of a lever at the forward end of the +cam-shaft. The cam-shaft is hollow, and serves as a channel for +the conveyance of lubricating oil to each of the camshaft +bearings. At the forward end of this shaft there is also +mounted an air pump for maintaining pressure on the fuel supply +tank, and a bevel gear tachometer drive. + +Lubrication of the engine is carried out by a full pressure +system. The oil is pumped through a single manifold, with seven +branches to the crankshaft main bearings, and then in turn +through the hollow crankshaft to the connecting-rod big ends and +thence through small tubes, already noted, to the small end +bearings. The oil pump has four pistons and two double valves +driven from a single eccentric shaft on which are mounted four +eccentrics. The pump is continuously submerged in oil; in order +to avoid great variations in pressure in the oil lines there is +a piston operated pressure regulator, cut in between the pump +and the oil lines. The two small pistons of the pump take fresh +oil from a tank located in the fuselage of the machine; one of +these delivers oil to the cam shaft, and one delivers to the +crankshaft; this fresh oil mixes with the used oil, returns to +the base, and back to the main large oil pump cylinders. By +means of these small pump pistons a constant quantity of oil is +kept in the motor, and the oil is continually being freshened by +means of the new oil coming in. All the oil pipes are very +securely fastened to the lower half of the crank case, and some +cooling of the oil is effected by air passing through channels +cast in the crank case on its way to the carburettor. + +A light steel manifold serves to connect the exhaust ports of +the cylinders to the main exhaust pipe, which is inclined about +25 degrees from vertical and is arranged to give on to the +atmosphere just over the top of the upper wing of the aeroplane. + +As regards carburation, an automatic air valve surrounds the +throat of the carburettor, maintaining normal composition of +mixture. A small jet is fitted for starting and running without +load. The channels cast in the crank chamber, already alluded +to in connection with oil-cooling, serve to warm the air before +it reaches the carburettor, of which the body is water-jacketed. + +Ignition of the engine is by means of two Bosch ZH6 magnetos, +driven at a speed of 2,175 revolutions per minute when the engine +is running at its normal speed of 1,450 revolutions. The maximum +advance of spark is 12 mm., or 32 degrees before the top dead +centre, and the firing order of the cylinders is 1,5,3,6,2,4. + +The radiator fitted to this engine, together with the +water-jackets, has a capacity of 25 litres of water, it is +rectangular in shape, and is normally tilted at an angle of 30 +degrees from vertical. Its weight is 26 kg., and it offers but +slight head resistance in flight. + +The radial type of engine, neglected altogether in Germany, was +brought to a very high state of perfection at the end of the +War period by British makers. Two makes, the Cosmos Engineering +Company's 'Jupiter' and 'Lucifer,' and the A.B.C. 'Wasp II' and +'Dragon Fly 1A' require special mention for their light weight +and reliability on trials. + +The Cosmos 'Jupiter' was--for it is no longer being made--a 450 +horse-power nine-cylinder radial engine, air-cooled, with the +cylinders set in one single row; it was made both geared to +reduce the propeller revolutions relatively to the crankshaft +revolutions, and ungeared; the normal power of the geared type +was 450 horse-power, and the total weight of the engine, +including carburettors, magnetos, etc., was only 757 lbs.; the +engine speed was 1,850 revolutions per minute, and the propeller +revolutions were reduced by the gearing to 1,200. Fitted to a +'Bristol Badger' aeroplane, the total weight was 2,800 lbs., +including pilot, passenger, two machine-guns, and full military +load; at 7,000 feet the registered speed, with corrections for +density, was 137 miles per hour; in climbing, the first 2,000 +feet was accomplished in 1 minute 4 seconds; 4,000 feet was +reached in 2 minutes 10 seconds; 6,000 feet was reached in 3 +minutes 33 seconds, and 7,000 feet in 4 minutes 15 seconds. +It was intended to modify the plane design and fit a new +propeller, in order to attain even better results, but, if +trials were made with these modifications, the results are not +obtainable. + +The Cosmos 'Lucifer' was a three-cylinder radial type engine of +100 horse-power, inverted Y design, made on the simplest possible +principles with a view to quantity production and extreme +reliability. The rated 100 horse-power was attained at 1,600 +revolutions per minute, and the cylinder dimensions were 5.75 +bore by 6.25 inches stroke. The cylinders were of aluminium and +steel mixture, with aluminium heads; overhead valves, operated by +push rods on the front side of the cylinders, were fitted, and a +simple reducing gear ran them at half engine speed. The crank +case was a circular aluminium casting, the engine being attached +to the fuselage of the aeroplane by a circular flange situated at +the back of the case; propeller shaft and crankshaft were +integral. Dual ignition was provided, the generator and +distributors being driven off the back end of the engine and the +distributors being easily accessible. Lubrication was by means +of two pumps, one scavenging and one suction, oil being fed under +pressure from the crankshaft. A single carburettor fed all three +cylinders, the branch pipe from the carburettor to the circular +ring being provided with an exhaust heater. The total weight of +the engine, 'all on,' was 280 lbs. + +The A.B.C. 'Wasp II,' made by Walton Motors, Limited, is a +seven-cylinder radial, air-cooled engine, the cylinders having a +bore of 4.75 inches and stroke 6.25 inches. The normal brake +horse-power at 1,650 revolutions is 160, and the maximum 200 at +a speed of 1,850 revolutions per minute. Lubrication is by +means of two rotary pumps, one feeding through the hollow +crankshaft to the crank pin, giving centrifugal feed to big end +and thence splash oiling, and one feeding to the nose of the +engine, dropping on to the cams and forming a permanent sump for +the gears on the bottom of the engine nose. Two carburettors +are fitted, and two two-spark magnetos, running at one and +three-quarters engine speed. The total weight of this engine is +350 lbs., or 1.75 lbs. per horse-power. Oil consumption at 1,850 +revolutions is .03 pints per horse-power per hour, and petrol +consumption is .56 pints per horsepower per hour. The engine +thus shows as very economical in consumption, as well as very +light in weight. + +The A.B.C. 'Dragon Fly 1A 'is a nine-cylinder radial engine +having one overhead inlet and two overhead exhaust valves per +cylinder. The cylinder dimensions are 5.5 inches bore by 6.5 +inches stroke, and the normal rate of speed, 1,650 revolutions +per minute, gives 340 horse-power. The oiling is by means of +two pumps, the system being practically identical with that of +the 'Wasp II.' Oil consumption is .021 pints per brake +horse-power per hour, and petrol consumption .56 pints--the +same as that of the 'Wasp II.' The weight of the complete +engine, including propeller boss, is 600 lbs., or 1,765 lbs. +per horse-power. + +These A.B.C. radials have proved highly satisfactory on tests, +and their extreme simplicity of design and reliability commend +them as engineering products and at the same time demonstrate +the value, for aero work, of the air-cooled radial +design--when this latter is accompanied by sound workmanship. +These and the Cosmos engines represent the minimum of weight per +horse-power yet attained, together with a practicable degree of +reliability, in radial and probably any aero engine design. + + + + APPENDIX A + +GENERAL MENSIER'S REPORT ON THE TRIALS OF CLEMENT ADER'S AVION. + + Paris, October 21, 1897. + +Report on the trials of M. Clement Ader's aviation apparatus. + +M. Ader having notified the Minister of War by letter, July 21, +1897, that the Apparatus of Aviation which he had agreed to +build under the conditions set forth in the convention of July +24th, 1894, was ready, and therefore requesting that trials be +undertaken before a Committee appointed for this purpose as per +the decision of August 4th, the Committee was appointed as +follows:-- + +Division General Mensier, Chairman; Division General Delambre, +Inspector General of the Permanent Works of Coast Defence, +Member of the Technical Committee of the Engineering Corps; +Colonel Laussedat, Director of the Conservatoire des Arts et +Metiers; Sarrau, Member of the Institute, Professor of +Mechanical Engineering at the Polytechnic School; Leaute, Member +of the Institute, Professor of Mechanical Engineering at the +Polytechnique School. + +Colonel Laussedat gave notice at once that his health and work +as Director of the Conservatoire des Arts et Metiers did not +permit him to be a member of the Committee; the Minister +therefore accepted his resignation on September 24th, and +decided not to replace him. + +Later on, however, on the request of the Chairman of the +Committee, the Minister appointed a new member General Grillon, +commanding the Engineer Corps of the Military Government of +Paris. + +To carry on the trials which were to take place at the camp of +Satory, the Minister ordered the Governor of the Military Forces +of Paris to requisition from the Engineer Corps, on the request +of the Chairman of the Committee, the men necessary to prepare +the grounds at Satory. + +After an inspection made on the 16th an aerodrome was chosen. +M. Ader's idea was to have it of circular shape with a width of +40 metres and an average diameter of 450 metres. The preliminary +work, laying out the grounds, interior and exterior +circumference, etc., was finished at the end of August; the work +of smoothing off the grounds began September 1st with forty-five +men and two rollers, and was finished on the day of the first +tests, October 12th. + +The first meeting of the Committee was held August 18th in M. +Ader's workshop; the object being to demonstrate the machine to +the Committee and give all the information possible on the tests +that were to be held. After a careful examination and after +having heard all the explanations by the inventor which were +deemed useful and necessary, the Committee decided that the +apparatus seemed to be built with a perfect understanding of the +purpose to be fulfilled as far as one could judge from a study +of the apparatus at rest; they therefore authorised M. Ader to +take the machine apart and carry it to the camp at Satory so as +to proceed with the trials. + +By letter of August 19th the Chairman made report to the Minister +of the findings of the Committee. + +The work on the grounds having taken longer than was anticipated, +the Chairman took advantage of this delay to call the Committee +together for a second meeting, during which M. Ader was to run +the two propulsive screws situated at the forward end of the +apparatus. + +The meeting was held October 2nd. It gave the Committee an +opportunity to appreciate the motive power in all its details; +firebox, boiler, engine, under perfect control, absolute +condensation, automatic fuel and feed of the liquid to be +vaporised, automatic lubrication and scavenging; everything, in +a word, seemed well designed and executed. + +The weights in comparison with the power of the engine realised +a considerable advance over anything made to date, since the two +engines weighed together realised 42 kg., the firebox and boiler +60 kg., the condenser 15 kg., or a total of 117 kg. for +approximately 40 horse-power or a little less than 3 kg. per +horse-power. + +One of the members summed up the general opinion by saying: +'Whatever may be the result from an aviation point of view, a +result which could not be foreseen for the moment, it was +nevertheless proven that from a mechanical point of view M. +Ader's apparatus was of the greatest interest and real +ingeniosity. He expressed a hope that in any case the machine +would not be lost to science.' + +The second experiment in the workshop was made in the presence +of the Chairman, the purpose being to demonstrate that the +wings, having a spread of 17 metres, were sufficiently strong +to support the weight of the apparatus. With this object in +view, 14 sliding supports were placed under each one of these, +representing imperfectly the manner in which the wings would +support the machine in the air; by gradually raising the +supports with the slides, the wheels on which the machine rested +were lifted from the ground. It was evident at that time that +the members composing the skeleton of the wings supported the +apparatus, and it was quite evident that when the wings were +supported by the air on every point of their surface, the stress +would be better equalised than when resting on a few supports, +and therefore the resistance to breakage would be considerably +greater. + +After this last test, the work on the ground being practically +finished, the machine was transported to Satory, assembled and +again made ready for trial. + +At first M. Ader was to manoeuvre the machine on the ground at +a moderate speed, then increase this until it was possible to +judge whether there was a tendency for the machine to rise; and +it was only after M. Ader had acquired sufficient practice that +a meeting of the Committee was to be called to be present at the +first part of the trials; namely, volutions of the apparatus on +the ground. + +The first test took place on Tuesday, October 12th, in the +presence of the Chairman of the Committee. It had rained a good +deal during the night and the clay track would have offered +considerable resistance to the rolling of the machine; +furthermore, a moderate wind was blowing from the south-west, +too strong during the early part of the afternoon to allow of +any trials. + +Toward sunset, however, the wind having weakened, M. Ader +decided to make his first trial; the machine was taken out of +its hangar, the wings were mounted and steam raised. M. Ader +in his seat had, on each side of him, one man to the right and +one to the left, whose duty was to rectify the direction of the +apparatus in the event that the action of the rear wheel as a +rudder would not be sufficient to hold the machine in a straight +course. + +At 5.25 p.m. the machine was started, at first slowly and then +at an increased speed; after 250 or 300 metres, the two men who +were being dragged by the apparatus were exhausted and forced to +fall flat on the ground in order to allow the wings to pass over +them, and the trip around the track was completed, a total of +1,400 metres, without incident, at a fair speed, which could be +estimated to be from 300 to 400 metres per minute. +Notwithstanding M. Ader's inexperience, this being the first +time that he had run his apparatus, he followed approximately +the chalk line which marked the centre of the track and he +stopped at the exact point from which he started. + +The marks of the wheels on the ground, which was rather soft, +did not show up very much, and it was clear that a part of the +weight of the apparatus had been supported by the wings, though +the speed was only about one-third of what the machine could do +had M. Ader used all its motive power; he was running at a +pressure of from 3 to 4 atmospheres, when he could have used 10 +to 12. + +This first trial, so fortunately accomplished, was of great +importance; it was the first time that a comparatively heavy +vehicle (nearly 400 kg., including the weight of the operator, +fuel, and water) had been set in motion by a tractive apparatus, +using the air solely as a propelling medium. The favourable +report turned in by the Committee after the meeting of October +2nd was found justified by the results demonstrated on the +grounds, and the first problem of aviation, namely, the creation +of efficient motive power, could be considered as solved, since +the propulsion of the apparatus in the air would be a great deal +easier than the traction on the ground, provided that the second +part of the problem, the sustaining of the machine in the air, +would be realised. + +The next day, Wednesday the 13th, no further trials were made +on account of the rain and wind. + +On Thursday the 14th the Chairman requested that General +Grillon, who had just been appointed a member of the Committee, +accompany him so as to have a second witness. + +The weather was fine, but a fairly strong, gusty wind was +blowing from the south. M. Ader explained to the two members +of the Committee the danger of these gusts, since at two points +of the circumference the wind would strike him sideways. The +wind was blowing in the direction A B, the apparatus starting +from C, and running in the direction shown by the arrow. The +first dangerous spot would be at B. The apparatus had been kept +in readiness in the event of the wind dying down. Toward sunset +the wind seemed to die down, as it had done on the evening of +the 12th. M. Ader hesitated, which, unfortunately, further +events only justified, but decided to make a new trial. + +At the start, which took place at 5.15 p.m., the apparatus, +having the wind in the rear, seemed to run at a fairly regular +speed; it was, nevertheless, easy to note from the marks of the +wheels on the ground that the rear part of the apparatus had been +lifted and that the rear wheel, being the rudder, had not been in +constant contact with the ground. When the machine came to the +neighbourhood of B, the two members of the Committee saw the +machine swerve suddenly out of the track in a semicircle, lean +over to the right and finally stop. They immediately proceeded +to the point where the accident had taken place and endeavoured +to find an explanation for the same. The Chairman finally +decided as follows: + +M. Ader was the victim of a gust of wind which he had feared as +he explained before starting out; feeling himself thrown out of +his course, he tried to use the rudder energetically, but at that +time the rear wheel was not in contact with the ground, and +therefore did not perform its function; the canvas rudder, which +had as its purpose the manoeuvring of the machine in the air, did +not have sufficient action on the ground. It would have been +possible without any doubt to react by using the propellers at +unequal speed, but M. Ader, being still inexperienced, had not +thought of this. Furthermore, he was thrown out of his course so +quickly that he decided, in order to avoid a more serious +accident, to stop both engines. This sudden stop produced the +half-circle already described and the fall of the machine on its +side. + +The damage to the machine was serious; consisting at first sight +of the rupture of both propellers, the rear left wheel and the +bending of the left wing tip. It will only be possible to +determine after the machine is taken apart whether the engine, +and more particularly the organs of transmission, have been put +out of line. + +Whatever the damage may be, though comparatively easy to repair, +it will take a certain amount of time, and taking into +consideration the time of year it is evident that the tests will +have to be adjourned for the present. + +As has been said in the above report, the tests, though +prematurely interrupted, have shown results of great importance, +and though the final results are hard to foresee, it would seem +advisable to continue the trials. By waiting for the return of +spring there will be plenty of time to finish the tests and it +will not be necessary to rush matters, which was a partial cause +of the accident. The Chairman of the Committee personally has +but one hope, and that is that a decision be reached accordingly. + + Division General, + Chairman of the Committee, + Mensier. + +Boulogne-sur-Seine, October 21st, 1897. + + Annex to the Report of October 21st. + +General Grillon, who was present at the trials of the 14th, and +who saw the report relative to what happened during that day, +made the following observations in writing, which are reproduced +herewith in quotation marks. The Chairman of the Committee does +not agree with General Grillon and he answers theseobservations +paragraph by paragraph. + +1. 'If the rear wheel (there is only one of these) left but +intermittent tracks on the ground, does that prove that the +machine has a tendency to rise when running at a certain speed?' + +Answer.--This does not prove anything in any way, and I was very +careful not to mention this in my report, this point being +exactly what was needed and that was not demonstrated during the +two tests made on the grounds. + +'Does not this unequal pressure of the two pair of wheels on the +ground show that the centre of gravity of the apparatus is +placed too far forward and that under the impulse of the +propellers the machine has a tendency to tilt forward, due to +the resistance of the air?' + +Answer.--The tendency of the apparatus to rise from the rear +when it was running with the wind seemed to be brought about by +the effects of the wind on the huge wings, having a spread of 17 +metres, and I believe that when the machine would have faced the +wind the front wheels would have been lifted. + +During the trials of October 12th, when a complete circuit of +the track was accomplished without incidents, as I and Lieut. +Binet witnessed, there was practically no wind. I was therefore +unable to verify whether during this circuit the two front +wheels or the rear wheel were in constant contact with the +ground, because when the trial was over it was dark (it was +5.30) and the next day it was impossible to see anything because +it had rained during the night and during Wednesday morning. +But what would prove that the rear wheel was in contact with the +ground at all times is the fact that M. Ader, though +inexperienced, did not swerve from the circular track, which +would prove that he steered pretty well with his rear +wheel--this he could not have done if he had been in the air. + +In the tests of the 12th, the speed was at least as great as on +the 14th. + +2. 'It would seem to me that if M. Ader thought that his rear +wheels were off the ground he should have used his canvas rudder +in order to regain his proper course; this was the best way of +causing the machine to rotate, since it would have given an +angular motion to the front axle.' + +Answer.--I state in my report that the canvas rudder whose +object was the manoeuvre of the apparatus in the air could have +no effect on the apparatus on the ground, and to convince +oneself of this point it is only necessary to consider the small +surface of this canvas rudder compared with the mass to be +handled on the ground, a weight of approximately 400 kg. +According to my idea, and as I have stated in my report, M. Ader +should have steered by increasing the speed on one of his +propellers and slowing down the other. He admitted afterward +that this remark was well founded, but that he did not have time +to think of it owing to the suddenness of the accident. + +3. 'When the apparatus fell on its side it was under the sole +influence of the wind, since M. Ader had stopped the machine. +Have we not a result here which will always be the same when the +machine comes to the ground, since the engines will always have +to be stopped or slowed down when coming to the ground? Here +seems to be a bad defect of the apparatus under trial.' + +Answer.--I believe that the apparatus fell on its side after +coming to a stop, not on account of the wind, but because the +semicircle described was on rough ground and one of the wheels +had collapsed. + Mensier. +October 27th, 1897. + + + + APPENDIX B + +Specification and Claims of Wright Patent, No. 821393. +Filed March 23rd, 1903. Issued May 22nd, 1906. Expires May +22nd, 1923. + +To all whom it may concern. + +Be it known that we, Orville Wright and Wilbur Wright, citizens +of the United States, residing in the city of Dayton, county of +Montgomery, and State of Ohio, have invented certain new and +useful Improvements in Flying Machines, of which the following +is a specification. + +Our invention relates to that class of flying-machines in which +the weight is sustained by the reactions resulting when one or +more aeroplanes are moved through the air edgewise at a small +angle of incidence, either by the application of mechanical +power or by the utilisation of the force of gravity. + +The objects of our invention are to provide means for +maintaining or restoring the equilibrium or lateral balance of +the apparatus, to provide means for guiding the machine both +vertically and horizontally, and to provide a structure +combining lightness, strength, convenience of construction and +certain other advantages which will hereinafter appear. + +To these ends our invention consists in certain novel features, +which we will now proceed to describe and will then particularly +point out in the claims. In the accompanying drawings, Figure I +1 is a perspective view of an apparatus embodying our invention +in one form. Fig. 2 is a plan view of the same, partly in +horizontal section and partly broken away. Fig. 3 is a side +elevation, and Figs. 4 and 5 are detail views, of one form of +flexible joint for connecting the upright standards with the +aeroplanes. + +In flying machines of the character to which this invention +relates the apparatus is supported in the air by reason of the +contact between the air and the under surface of one or more +aeroplanes, the contact surface being presented at a small angle +of incidence to the air. The relative movements of the air and +aeroplane may be derived from the motion of the air in the form +of wind blowing in the direction opposite to that in which the +apparatus is travelling or by a combined downward and forward +movement of the machine, as in starting from an elevated +position or by combination of these two things, and in either +case the operation is that of a soaring-machine, while power +applied to the machine to propel it positively forward will +cause the air to support the machine in a similar manner. In +either case owing to the varying conditions to be met there are +numerous disturbing forces which tend to shift the machine from +the position which it should occupy to obtain the desired +results. It is the chief object of our invention to provide +means for remedying this difficulty, and we will now proceed to +describe the construction by means of which these results are +accomplished. + +In the accompanying drawing we have shown an apparatus embodying +our invention in one form. In this illustrative embodiment the +machine is shown as comprising two parallel superposed +aeroplanes, 1 and 2, may be embodied in a structure having a +single aeroplane. Each aeroplane is of considerably greater width +from side to side than from front to rear. The four corners of +the upper aeroplane are indicated by the reference letters a, b, +c, and d, while the corresponding corners of the lower aeroplane +2 are indicated by the reference letters e, f, g, and h. The +marginal lines ab and ef indicate the front edges of the +aeroplanes, the lateral margins of the upper aeroplane are +indicated, respectively, by the lines ad and bc, the lateral +margins of the lower aeroplane are indicated, respectively, by +the lines eh and fg, while the rear margins of the upper and +lower aeroplanes are indicated, respectively, by the lines cd and +gh. + +Before proceeding to a description of the fundamental theory of +operation of the structure we will first describe the preferred +mode of constructing the aeroplanes and those portions of the +structure which serve to connect the two aeroplanes. + +Each aeroplane is formed by stretching cloth or other suitable +fabric over a frame composed of two parallel transverse spars 3, +extending from side to side of the machine, their ends being +connected by bows 4 extending from front to rear of the machine. +The front and rear spars 3 of each aeroplane are connected by a +series of parallel ribs 5, which preferably extend somewhat +beyond the rear spar, as shown. These spars, bows, and ribs are +preferably constructed of wood having the necessary strength, +combined with lightness and flexibility. Upon this framework +the cloth which forms the supporting surface of the aeroplane is +secured, the frame being enclosed in the cloth. The cloth for +each aeroplane previous to its attachment to its frame is cut on +the bias and made up into a single piece approximately the size +and shape of the aeroplane, having the threads of the fabric +arranged diagonally to the transverse spars and longitudinal +ribs, as indicated at 6 in Fig. 2. Thus the diagonal threads of +the cloth form truss systems with the spars and ribs, the threads +constituting the diagonal members. A hem is formed at the rear +edge of the cloth to receive a wire 7, which is connected to the +ends of the rear spar and supported by the rearwardly-extending +ends of the longitudinal ribs 5, thus forming a +rearwardly-extending flap or portion of the aeroplane. This +construction of the aeroplane gives a surface which has very +great strength to withstand lateral and longitudinal strains, at +the same time being capable of being bent or twisted in the +manner hereinafter described. + +When two aeroplanes are employed, as in the construction +illustrated, they are connected together by upright standards 8. +These standards are substantially rigid, being preferably +constructed of wood and of equal length, equally spaced along +the front and rear edges of the aeroplane, to which they are +connected at their top and bottom ends by hinged joints or +universal joints of any suitable description. We have shown one +form of connection which may be used for this purpose in Figs. 4 +and 5 of the drawings. In this construction each end of the +standard 8 has secured to it an eye 9 which engages with a hook +10, secured to a bracket plate 11, which latter plate is in +turn fastened to the spar 3. Diagonal braces or stay-wires 12 +extend from each end of each standard to the opposite ends of +the adjacent standards, and as a convenient mode of attaching +these parts I have shown a hook 13 made integral with the hook +10 to receive the end of one of the stay-wires, the other +stay-wire being mounted on the hook 10. The hook 13 is shown +as bent down to retain the stay-wire in connection to it, while +the hook 10 is shown as provided with a pin 14 to hold the +staywire 12 and eye 9 in position thereon. It will be seen that +this construction forms a truss system which gives the whole +machine great transverse rigidity and strength, while at the +same time the jointed connections of the parts permit the +aeroplanes to be bent or twisted in the manner which we will now +proceed to describe. + +15 indicates a rope or other flexible connection extending +lengthwise of the front of the machine above the lower +aeroplane, passing under pulleys or other suitable guides 16 at +the front corners e and f of the lower aeroplane, and extending +thence upward and rearward to the upper rear corners c and d, of +the upper aeroplane, where they are attached, as indicated at +17. To the central portion of the rope there is connected a +laterally-movable cradle 18, which forms a means for moving the +rope lengthwise in one direction or the other, the cradle being +movable toward either side of the machine. We have devised this +cradle as a convenient means for operating the rope 15, and the +machine is intended to be generally used with the operator lying +face downward on the lower aeroplane, with his head to the +front, so that the operator's body rests on the cradle, and the +cradle can be moved laterally by the movements of the operator's +body. It will be understood, however, that the rope 15 may be +manipulated in any suitable manner. + +19 indicates a second rope extending transversely of the +machine along the rear edge of the body portion of the lower +aeroplane, passing under suitable pulleys or guides 20 at the +rear corners g and h of the lower aeroplane and extending thence +diagonally upward to the front corners a and b of the upper +aeroplane, where its ends are secured in any suitable manner, as +indicated at 21. + +Considering the structure so far as we have now described it, +and assuming that the cradle 18 be moved to the right in Figs. +1 and 2, as indicated by the arrows applied to the cradle in +Fig. 1 and by the dotted lines in Fig. 2, it will be seen that +that portion of the rope 15 passing under the guide pulley at +the corner e and secured to the corner d will be under tension, +while slack is paid out throughout the other side or half of the +rope 15. The part of the rope 15 under tension exercises a +downward pull upon the rear upper corner d of the structure and +an upward pull upon the front lower corner e, as indicated by +the arrows. This causes the corner d to move downward and the +corner e to move upward. As the corner e moves upward it +carries the corner a upward with it, since the intermediate +standard 8 is substantially rigid and maintains an equal +distance between the corners a and e at all times. Similarly, +the standard 8, connecting the corners d and h, causes the +corner h to move downward in unison with the corner d. Since +the corner a thus moves upward and the corner h moves downward, +that portion of the rope 19 connected to the corner a will be +pulled upward through the pulley 20 at the corner h, and the +pull thus exerted on the rope 19 will pull the corner b on the +other wise of the machine downward and at the same time pull the +corner g at said other side of the machine upward. This results +in a downward movement of the corner b and an upward movement of +the corner c. Thus it results from a lateral movement of the +cradle 18 to the right in Fig. 1 that the lateral margins ad +and eh at one side of the machine are moved from their normal +positions in which they lie in the normal planes of their +respective aeroplanes, into angular relations with said normal +planes, each lateral margin on this side of the machine being +raised above said normal plane at its forward end and depressed +below said normal plane at its rear end, said lateral margins +being thus inclined upward and forward. At the same time a +reverse inclination is imparted to the lateral margins bc end fg +at the other side of the machine, their inclination being +downward and forward. These positions are indicated in dotted +lines in Fig. 1 of the drawings. A movement of the cradle 18 in +the opposite direction from its normal position will reverse the +angular inclination of the lateral margins of the aeroplanes in +an obvious manner. By reason of this construction it will be +seen that with the particular mode of construction now under +consideration it is possible to move the forward corner of the +lateral edges of the aeroplane on one side of the machine either +above or below the normal planes of the aeroplanes, a reverse +movement of the forward corners of the lateral margins on the +other side of the machine occurring simultaneously. During this +operation each aeroplane is twisted or distorted around a line +extending centrally across the same from the middle of one +lateral margin to the middle of the other lateral margin, the +twist due to the moving of the lateral margins to different +angles extending across each aeroplane from side to side, so that +each aeroplane surface is given a helicoidal warp or twist. We +prefer this construction and mode of operation for the reason +that it gives a gradually increasing angle to the body of each +aeroplane from the centre longitudinal line thereof outward to +the margin, thus giving a continuous surface on each side of the +machine, which has a gradually increasing or decreasing angle of +incidence from the centre of the machine to either side. We wish +it to be understood, however, that our invention is not limited +to this particular construction, since any construction whereby +the angular relations of the lateral margins of the aeroplanes +may be varied in opposite directions with respect to the normal +planes of said aeroplanes comes within the scope of our +invention. Furthermore, it should be understood that while the +lateral margins of the aeroplanes move to different angular +positions with respect to or above and below the normal planes of +said aeroplanes, it does not necessarily follow that these +movements bring the opposite lateral edges to different angles +respectively above and below a horizontal plane since the normal +planes of the bodies of the aeroplanes are inclined to the +horizontal when the machine is in flight, said inclination being +downward from front to rear, and while the forward corners on one +side of the machine may be depressed below the normal planes of +the bodies of the aeroplanes said depression is not necessarily +sufficient to carry them below the horizontal planes passing +through the rear corners on that side. Moreover, although we +prefer to so construct the apparatus that the movements of the +lateral margins on the opposite sides of the machine are equal in +extent and opposite m direction, yet our invention is not limited +to a construction producing this result, since it may be +desirable under certain circumstances to move the lateral margins +on one side of the machine just described without moving the +lateral margins on the other side of the machine to an equal +extent in the opposite direction. Turning now to the purpose of +this provision for moving the lateral margins of the aeroplanes +in the manner described, it should be premised that owing to +various conditions of wind pressure and other causes the body of +the machine is apt to become unbalanced laterally, one side +tending to sink and the other side tending to rise, the machine +turning around its central longitudinal axis. The provision +which we have just described enables the operator to meet this +difficulty and preserve the lateral balance of the machine. +Assuming that for some cause that side of the machine which lies +to the left of the observer in Figs. 1 and 2 has shown a +tendency to drop downward, a movement of the cradle 18 to the +right of said figures, as herein before assumed, will move the +lateral margins of the aeroplanes in the manner already +described, so that the margins ad and eh will be inclined +downward and rearward, and the lateral margins bc and fg will be +inclined upward and rearward with respect to the normal planes +of the bodies of the aeroplanes. With the parts of the machine +in this position it will be seen that the lateral margins ad +and eh present a larger angle of incidence to the resisting +air, while the lateral margins on the other side of the machine +present a smaller angle of incidence. Owing to this fact, the +side of the machine presenting the larger angle of incidence +will tend to lift or move upward, and this upward movement will +restore the lateral balance of the machine. When the other side +of the machine tends to drop, a movement of the cradle 18 in the +reverse direction will restore the machine to its normal lateral +equilibrium. Of course, the same effect will be produced in the +same way in the case of a machine employing only a single +aeroplane. + +In connection with the body of the machine as thus operated we +employ a vertical rudder or tail 22, so supported as to turn +around a vertical axis. This rudder is supported at the rear +ends on supports or arms 23, pivoted at their forward ends to +the rear margins of the upper and lower aeroplanes, respectively. +These supports are preferably V-shaped, as shown, so that their +forward ends are comparatively widely separated, their pivots +being indicated at 24. Said supports are free to swing upward at +their free rear ends, as indicated in dotted lines in Fig. 3, +their downward movement being limited in any suitable manner. +The vertical pivots of the rudder 22 are indicated at 25, and one +of these pivots has mounted thereon a sheave or pulley 26, around +which passes a tiller-rope 27, the ends of which are extended out +laterally and secured to the rope 19 on opposite sides of the +central point of said rope. By reason of this construction the +lateral shifting of the cradle 18 serves to turn the rudder to +one side or the other of the line of flight. It will be observed +in this connection that the construction is such that the rudder +will always be so turned as to present its resisting surface on +that side of the machine on which the lateral margins of the +aeroplanes present the least angle of resistance. The reason of +this construction is that when the lateral margins of the +aeroplanes are so turned in the manner hereinbefore described as +to present different angles of incidence to the atmosphere, that +side presenting the largest angle of incidence, although being +lifted or moved upward in the manner already described, at the +same time meets with an increased resistance to its forward +motion, while at the same time the other side of the machine, +presenting a smaller angle of incidence, meets with less +resistance to its forward motion and tends to move forward more +rapidly than the retarded side. This gives the machine a +tendency to turn around its vertical axis, and this tendency if +not properly met will not only change the direction of the front +of the machine, but will ultimately permit one side thereof to +drop into a position vertically below the other side with the +aero planes in vertical position, thus causing the machine to +fall. The movement of the rudder, hereinbefore described, +prevents this action, since it exerts a retarding influence on +that side of the machine which tends to move forward too rapidly +and keeps the machine with its front properly presented to the +direction of flight and with its body properly balanced around +its central longitudinal axis. The pivoting of the supports 23 +so as to permit them to swing upward prevents injury to the +rudder and its supports in case the machine alights at such an +angle as to cause the rudder to strike the ground first, the +parts yielding upward, as indicated in dotted lines in Fig. 3, +and thus preventing injury or breakage. We wish it to be +understood, however, that we do not limit ourselves to the +particular description of rudder set forth, the essential being +that the rudder shall be vertical and shall be so moved as to +present its resisting surface on that side of the machine which +offers the least resistance to the atmosphere, so as to +counteract the tendency of the machine to turn around a vertical +axis when the two sides thereof offer different resistances to +the air. + +From the central portion of the front of the machine struts 28 +extend horizontally forward from the lower aeroplane, and struts +29 extend downward and forward from the central portion of the +upper aeroplane, their front ends being united to the struts 28, +the forward extremities of which are turned up, as indicated at +30. These struts 28 and 29 form truss-skids projecting in front +of the whole frame of the machine and serving to prevent the +machine from rolling over forward when it alights. The struts 29 +serve to brace the upper portion of the main frame and resist its +tendency to move forward after the lower aeroplane has been +stopped by its contact with the earth, thereby relieving the rope +19 from undue strain, for it will be understood that when the +machine comes into contact with the earth, further forward +movement of the lower portion thereof being suddenly arrested, +the inertia of the upper portion would tend to cause it to +continue to move forward if not prevented by the struts 29, and +this forward movement of the upper portion would bring a very +violent strain upon the rope 19, since it is fastened to the +upper portion at both of its ends, while its lower portion is +connected by the guides 20 to the lower portion. The struts 28 +and 29 also serve to support the front or horizontal rudder, the +construction of which we will now proceed to describe. + +The front rudder 31 is a horizontal rudder having a flexible +body, the same consisting of three stiff crosspieces or sticks +32, 33, and 34, and the flexible ribs 35, connecting said +cross-pieces and extending from front to rear. The frame thus +provided is covered by a suitable fabric stretched over the same +to form the body of the rudder. The rudder is supported from +the struts 29 by means of the intermediate cross-piece 32, which +is located near the centre of pressure slightly in front of a +line equidistant between the front and rear edges of the rudder, +the cross-piece 32 forming the pivotal axis of the rudder, so as +to constitute a balanced rudder. To the front edge of the +rudder there are connected springs 36 which springs are +connected to the upturned ends 30 of the struts 28, the +construction being such that said springs tend to resist any +movement either upward or downward of the front edge of the +horizontal rudder. The rear edge of the rudder lies immediately +in front of the operator and may be operated by him in any +suitable manner. We have shown a mechanism for this purpose +comprising a roller or shaft 37, which may be grasped by the +operator so as to turn the same in either direction. Bands 38 +extend from the roller 37 forward to and around a similar roller +or shaft 39, both rollers or shafts being supported in suitable +bearings on the struts 28. The forward roller or shaft has +rearwardly-extending arms 40, which are connected by links 41 +with the rear edge of the rudder 31. The normal position of the +rudder 31 is neutral or substantially parallel with the +aeroplanes 1 and 2; but its rear edge may be moved upward or +downward, so as to be above or below the normal plane of said +rudder through the mechanism provided for that purpose. It will +be seen that the springs 36 will resist any tendency of the +forward edge of the rudder to move in either direction, so that +when force is applied to the rear edge of said rudder the +longitudinal ribs 35 bend, and the rudder thus presents a +concave surface to the action of the wind either above or below +its normal plane, said surface presenting a small angle of +incidence at its forward portion and said angle of incidence +rapidly increasing toward the rear. This greatly increases the +efficiency of the rudder as compared with a plane surface of +equal area. By regulating the pressure on the upper and lower +sides of the rudder through changes of angle and curvature in +the manner described a turning movement of the main structure +around its transverse axis may be effected, and the course of +the machine may thus be directed upward or downward at the will +of the operator and the longitudinal balance thereof maintained. + +Contrary to the usual custom, we place the horizontal rudder in +front of the aeroplanes at a negative angle and employ no +horizontal tail at all. By this arrangement we obtain a forward +surface which is almost entirely free from pressure under +ordinary conditions of flight, but which even if not moved at +all from its original position becomes an efficient +lifting-surface whenever the speed of the machine is +accidentally reduced very much below the normal, and thus +largely counteracts that backward travel of the centre of +pressure on the aeroplanes which has frequently been productive +of serious injuries by causing the machine to turn downward and +forward and strike the ground head-on. We are aware that a +forward horizontal rudder of different construction has been +used in combination with a supporting surface and a rear +horizontal-rudder; but this combination was not intended to +effect and does not effect the object which we obtain by the +arrangement hereinbefore described. + +We have used the term 'aeroplane' in this specification and the +appended claims to indicate the supporting surface or supporting +surfaces by means of which the machine is sustained in the air, +and by this term we wish to be understood as including any +suitable supporting surface which normally is substantially +flat, although. Of course, when constructed of cloth or other +flexible fabric, as we prefer to construct them, these surfaces +may receive more or less curvature from the resistance of the +air, as indicated in Fig. 3. + +We do not wish to be understood as limiting ourselves strictly +to the precise details of construction hereinbefore described +and shown in the accompanying drawings, as it is obvious that +these details may be modified without departing from the +principles of our invention. For instance, while we prefer the +construction illustrated in which each aeroplane is given a +twist along its entire length in order to set its opposite +lateral margins at different angles, we have already pointed out +that our invention is not limited to this form of construction, +since it is only necessary to move the lateral marginal +portions, and where these portions alone are moved only those +upright standards which support the movable portion require +flexible connections at their ends. + +Having thus fully described our invention, what we claim as new, +and desire to secure by Letters Patent, is:-- + +1. In a flying machine, a normally flat aeroplane having +lateral marginal portions capable of movement to different +positions above or below the normal plane of the body of the +aeroplane, such movement being about an axis transverse to the +line of flight, whereby said lateral marginal portions may be +moved to different angles relatively to the normal plane of the +body of the aeroplane, so as to present to the atmosphere +different angles of incidence, and means for so moving said +lateral marginal portions, substantially as described. + +2. In a flying machine, the combination, with two normally +parallel aeroplanes, superposed the one above the other, of +upright standards connecting said planes at their margins, the +connections between the standards and aeroplanes at the lateral +portions of the aeroplanes being by means of flexible joints, +each of said aeroplanes having lateral marginal portions capable +of movement to different positions above or below the normal +plane of the body of the aeroplane, such movement being about an +axis transverse to the line of flight, whereby said lateral +marginal portions may be moved to different angles relatively to +the normal plane of the body of the aeroplane, so as to present +to the atmosphere different angles of incidence, the standards +maintaining a fixed distance between the portions of the +aeroplanes which they connect, and means for imparting such +movement to the lateral marginal portions of the aeroplanes, +substantially as described. + +3. In a flying machine, a normally flat aeroplane having +lateral marginal portions capable of movement to different +positions above or below the normal plane of the body of the +aeroplane, such movement being about an axis transverse to the +line of flight, whereby said lateral marginal portions may be +moved to different angles relatively to the normal plane of the +body of the aeroplane, and also to different angles relatively +to each other, so as to present to the atmosphere different +angles of incidence, and means for simultaneously imparting such +movement to said lateral marginal portions, substantially as +described. + +4. In a flying machine, the combination, with parallel +superposed aeroplanes, each having lateral marginal portions +capable of movement to different positions above or below the +normal plane of the body of the aeroplane, such movement being +about an axis transverse to the line of flight, whereby said +lateral marginal portions may be moved to different angles +relatively to the normal plane of the body of the aeroplane, and +to different angles relatively to each other, so as to present +to the atmosphere different angles of incidence, of uprights +connecting said aeroplanes at their edges, the uprights +connecting the lateral portions of the aeroplanes being +connected with said aeroplanes by flexible joints, and means for +simultaneously imparting such movement to said lateral marginal +portions, the standards maintaining a fixed distance between the +parts which they connect, whereby the lateral portions on the +same side of the machine are moved to the same angle, +substantially as described. + +5. In a flying machine, an aeroplane having substantially the +form of a normally flat rectangle elongated transversely to the +line of flight, in combination which means for imparting to the +lateral margins of said aeroplane a movement about an axis lying +in the body of the aeroplane perpendicular to said lateral +margins, and thereby moving said lateral margins into different +angular relations to the normal plane of the body of the +aeroplane, substantially as described. + +6. In a flying machine, the combination, with two superposed +and normally parallel aeroplanes, each having substantially the +form of a normally flat rectangle elongated transversely to the +line of flight, of upright standards connecting the edges of +said aeroplanes to maintain their equidistance, those standards +at the lateral portions of said aeroplanes being connected +therewith by flexible joints, and means for simultaneously +imparting to both lateral margins of both aeroplanes a movement +about axes which are perpendicular to said margins and in the +planes of the bodies of the respective aeroplanes, and thereby +moving the lateral margins on the opposite sides of the machine +into different angular relations to the normal planes of the +respective aeroplanes, the margins on the same side of the +machine moving to the same angle, and the margins on one side of +the machine moving to an angle different from the angle to which +the margins on the other side of the machine move, substantially +as described. + +7. In a flying machine, the combination, with an aeroplane, and +means for simultaneously moving the lateral portions thereof +into different angular relations to the normal plane of the body +of the aeroplane and to each other, so as to present to the +atmosphere different angles of incidence, of a vertical rudder, +and means whereby said rudder is caused to present to the wind +that side thereof nearest the side of the aeroplane having the +smaller angle of incidence and offering the least resistance to +the atmosphere, substantially as described. + +8. In a flying machine, the combination, with two superposed +and normally parallel aeroplanes, upright standards connecting +the edges of said aeroplanes to maintain their equidistance, +those standards at the lateral portions of said aeroplanes being +connected therewith by flexible joints, and means for +simultaneously moving both lateral portions of both aeroplanes +into different angular relations to the normal planes of the +bodies of the respective aeroplanes, the lateral portions on one +side of the machine being moved to an angle different from that +to which the lateral portions on the other side of the machine +are moved, so as to present different angles of incidence at the +two sides of the machine, of a vertical rudder, and means +whereby said rudder is caused to present to the wind that side +thereof nearest the side of the aeroplanes having the smaller +angle of incidence and offering the least resistance to the +atmosphere, substantially as described. + +9. In a flying machine, an aeroplane normally flat and +elongated transversely to the line of flight, in combination +with means for imparting to said aeroplane a helicoidal warp +around an axis transverse to the line of flight and extending +centrally along the body aeroplane in the direction of the +elongation aeroplane, substantially as described. + +10. In a flying machine, two aeroplanes, each normally flat and +elongated transversely to the line of flight, and upright +standards connecting the edges of said aeroplanes to maintain +their equidistance, the connections between said standards and +aeroplanes being by means of flexible joints, in combination +with means for simultaneously imparting to each of said +aeroplanes a helicoidal warp around an axis transverse to the +line of flight and extending centrally along the body of the +aeroplane in the direction of the aeroplane, substantially as +described. + +11. In a flying machine, two aeroplanes, each normally flat +and elongated transversely to the line of flight, and upright +standards connecting the edges of said aeroplanes to maintain +their equidistance, the connections between such standards and +aeroplanes being by means of flexible joints, in combination +with means for simultaneously imparting to each of said +aeroplanes a helicoidal warp around an axis transverse to the +line of flight and extending centrally along the body of the +aeroplane in the direction of the elongation of the +aeroplane, a vertical rudder, and means whereby said rudder is +caused to present to the wind that side thereof nearest the side +of the aeroplanes having the smaller angle of incidence and +offering the least resistance to the atmosphere, substantially +as described. + +12. In a flying machine, the combination, with an aeroplane, of +a normally flat and substantially horizontal flexible rudder, +and means for curving said rudder rearwardly and upwardly or +rearwardly and downwardly with respect to its normal plane, +substantially as described. + +13. In a flying machine, the combination, with an aeroplane, of +a normally flat and substantially horizontal flexible rudder +pivotally mounted on an axis transverse to the line of flight +near its centre, springs resisting vertical movement of the +front edge of said rudder, and means for moving the rear edge of +said rudder, above or below the normal plane thereof, +substantially as described. + +14. A flying machine comprising superposed connected aeroplanes +means for moving the opposite lateral portions of said +aeroplanes to different angles to the normal planes thereof, a +vertical rudder, means for moving said vertical rudder toward +that side of the machine presenting the smaller angle of +incidence and the least resistance to the atmosphere, and a +horizontal rudder provided with means for presenting its upper +or under surface to the resistance of the atmosphere, +substantially as described. + +15. A flying machine comprising superposed connected +aeroplanes, means for moving the opposite lateral portions of +said aeroplanes to different angles to the normal planes +thereof, a vertical rudder, means for moving said vertical +rudder toward that side of the machine presenting the smaller +angle of incidence and the least resistance to the atmosphere, +and a horizontal rudder provided with means for presenting its +upper or under surface to the resistance of the atmosphere, said +vertical rudder being located at the rear of the machine and +said horizontal rudder at the front of the machine, +substantially as described. + +16. In a flying machine, the combination, with two superposed +and connected aeroplanes, of an arm extending rearward from each +aeroplane, said arms being parallel and free to swing upward at +their rear ends, and a vertical rudder pivotally mounted in the +rear ends of said arms, substantially as described. + +17. A flying machine comprising two superposed aeroplanes, +normally flat but flexible, upright standards connecting the +margins of said aeroplanes, said standards being connected to +said aeroplanes by universal joints, diagonal stay-wires +connecting the opposite ends of the adjacent standards, a rope +extending along the front edge of the lower aeroplane, passing +through guides at the front corners thereof, and having its ends +secured to the rear corners of the upper aeroplane, and a rope +extending along the rear edge of the lower aeroplane, passing +through guides at the rear corners thereof, and having its ends +secured to the front corners of the upper aeroplane, +substantially as described. + +18. A flying machine comprising two superposed aeroplanes, +normally flat but flexible, upright standards connecting the +margins of said aeroplanes, said standards being connected to +said aeroplanes by universal joints, diagonal stay-wires +connecting the opposite ends of the adjacent standards, a rope +extending along the front edge of the lower aeroplane, passing +through guides at the front corners thereof, and having its ends +secured to the rear corners of the upper aeroplane, and a rope +extending along the rear edge of the lower aeroplane, passing +through guides at the rear corners thereof, and having its ends +secured to the front corners of the upper aeroplane, in +combination with a vertical rudder, and a tiller-rope connecting +said rudder with the rope extending along the rear edge of the +lower aeroplane, substantially as described. + ORVILLE WRIGHT. + WILBUR WRIGHT. +Witnesses: +Chas. E. Taylor. +E. Earle Forrer. + + + + APPENDIX C + +Proclamation published by the French Government on balloon +ascents, 1783. + + NOTICE TO THE PUBLIC! PARIS, 27TH AUGUST, 1783. + +On the Ascent of balloons or globes in the air. The one +in question has been raised in Paris this day, 27th August, +1783, at 5 p.m., in the Champ de Mars. + +A Discovery has been made, which the Government deems it right to +make known, so that alarm be not occasioned to the people. + +On calculating the different weights of hot air, hydrogen gas, +and common air, it has been found that a balloon filled with +either of the two former will rise toward heaven till it is in +equilibrium with the surrounding air, which may not happen until +it has attained a great height. + +The first experiment was made at Annonay, in Vivarais, MM. +Montgolfier, the inventors; a globe formed of canvas and paper, +105 feet in circumference, filled with heated air, reached an +uncalculated height. The same experiment has just been renewed +in Paris before a great crowd. A globe of taffetas or light +canvas covered by elastic gum and filled with inflammable air, +has risen from the Champ de Mars, and been lost to view in the +clouds, being borne in a north-westerly direction. One cannot +foresee where it will descend. + +It is proposed to repeat these experiments on a larger scale. +Any one who shall see in the sky such a globe, which resembles +'la lune obscurcie,' should be aware that, far from being an +alarming phenomenon, it is only a machine that cannot possibly +cause any harm, and which will some day prove serviceable to the +wants of society. + +(Signed) DE SAUVIGNY. +LENOIR. + + + + + +End Project Gutenberg Etext of A History of Aeronautics + diff --git a/old/haero10.zip b/old/haero10.zip Binary files differnew file mode 100644 index 0000000..d9257f8 --- /dev/null +++ b/old/haero10.zip |