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+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
+
+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. Charles Vivian
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