The War in the Air; Vol. 1 / The Part played in the Great War by the Royal Air Force

by Sir Walter Alexander Raleigh

The wings of a flying machine, it has been said, are called planes, but they are not true planes. Like the wings of a bird, they are 'cambered', that is to say, they curve upward from the leading edge and downward again to the trailing edge. Some of the most valuable work contributed by the laboratory to the science of flight has had for its object the determination of the best form of camber, or curve of the plane. In the result, that form of camber has been found to be best which attains its maximum depth a little way only behind the leading edge, and gradually becomes shallower towards the trailing edge. Such a form of curve produces a comparatively smooth and untroubled partial vacuum above the plane, just behind its leading edge, and this vacuum is the factor of chief importance in the lift of the plane.

The above is a brief and rough statement of some principles of aviation which have been ascertained by long experiment and the labour of many minds. It is by experiment that flight has been achieved. The Newton who shall reduce all the observed phenomena to a few broad and simple laws is yet to come. A bird is simpler than an aeroplane in that its wings both support it and drive it forward, whereas all aerial machines, both those that are heavier than air and those that are lighter than air, are at present driven forward by the thrust of an airscrew, revolving at the rate of some twenty to thirty times a second.

There are only two kinds of flying machine, the lighter than air and the heavier than air, of which two kinds the simplest types are the soap-bubble and the arrow. These two kinds have often been in competition with each other; and their rivalry, which has sometimes delayed progress, still continues. The chief practical objection to machines lighter than air is that they are buoyed up by vulnerable receptacles containing hydrogen or some other highly inflammable gas. As soon as helium, which is a light non-inflammable gas, shall be produced in quantity at a reasonable expense, this objection will be lessened. The advantage of the lighter-than-air, or floating, machine over the heavier-than-air, or soaring, machine is that it can remain stationary in the air without loss of height, and that its great size and lifting power enable it to supply comfortable quarters for its staff, who not only travel in it, but, if need be, can inhabit it for days. The airship has a promising future, but it can never wholly supersede the soaring machine, which is heavier than air, and flies as birds fly.

A fascinating story, part legend, part fiction, might be told of the earliest reputed inventors. The fable of Daedalus perhaps grew up round the memory of a man of mechanical genius, for Daedalus was the author of many inventions before he flew from Crete to Italy. Aulus Gellius, in his entertaining book of anecdotes called the Attic Nights, tells how the philosopher Archytas of Tarentum invented a mechanical pigeon, which was filled with some kind of light air, and flew. The two schools of aeronautics were here reconciled. Other mechanists were Roger Bacon, who is reported to have designed a flying chariot; and Regiomontanus, astronomer and mathematician, who made a mechanical eagle which flew to meet the Emperor Charles the Fifth, on his solemn entry into the city of Nuremberg. It is not necessary to inquire whether these stories are true or false; what is certain is that the inventors did not leave their inventions as a legacy to their fellows. For a like reason Leonardo da Vinci, who busied himself with a mechanism which should enable man to operate wings with his legs, and who left a short treatise on the art of flight, has no place in the history. His mechanism is merely a drawing; his treatise remained in manuscript. The adventurers who risked their lives on wings of their own making are truer ancestors of the flying man. In 1507 John Damian, who was held in esteem as an alchemist and physician at the court of King James IV of Scotland, 'took in hand to fly with wings, and to that effect he caused make a pair of wings of feathers, which being fastened upon him, he flew off the castle wall of Stirling, but shortly he fell to the ground and brake his thigh-bone'.[1] The poet Dunbar attacked him in a satirical poem, and the reputation of a charlatan has stuck to him, but he deserves credit for his courageous attempt. So does the Marquis de Bacqueville, who, in 1742, attached to his arms and legs planes of his own design, and launched himself from an upper story of his house in Paris, in the attempt to fly across the river Seine to the Tuileries, about two hundred yards away. He glided some distance, and then fell on a washerwoman's barge in the stream, breaking his leg in the fall. These and other disastrous attempts might be defended in the words of Wilbur Wright, written in 1901, while he was experimenting with his own gliders. 'There are two ways', he says, 'of learning how 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 safest; 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.'[2] This pronouncement, by the highest authority, may serve as an apology for some of those whose attempts were reckoned madness or quackery, and whose misfortunes, during many long centuries, are the only material available for the history of human flight.

Two periods of modern European history are notable for a quickening of human interest in the problem of aerial navigation. They are the age of Louis XIV of France, and the age of the French Revolution. Both were times of great progress in science, and of illimitable hopes; but the earlier period, which in England witnessed the foundation of the Royal Society, was notable chiefly for advance in the physical and mathematical sciences; while the later period was more addicted to chemistry, and was the age of Lavoisier, Priestley, Cavendish, and Black. The former age, though it attained to nothing practical, made some progress in the theory of flight; the latter age invented the balloon.

The Royal Society took its origin in the meetings in London, during the troublous times of the Civil War, of 'divers worthy persons inquisitive into natural philosophy'. One of these worthy persons was John Wilkins, mathematician, philosopher, and divine, who, being parliamentarian in his sympathies, was, on the expulsion of the Royalists from Oxford, made Warden of Wadham College in that University. At Wadham, in the Warden's lodgings, the 'Experimental philosophical Club', as Aubrey calls it, renewed its meetings. Sprat, the early historian of the Royal Society, explains that religion and politics were forbidden topics. 'To have been always tossing about some theological question would have been to make that their private diversion of which they had had more than enough in public; to have been musing on the Civil Wars would have made them melancholy; therefore Nature alone could entertain them.' After the Restoration a meeting was held at Gresham College in London, and a committee was appointed, with Wilkins as chairman, to draw up a scheme for the Royal Society. The King approved of the scheme submitted to him, and the society received its charter in 1662.

Wilkins was a famous man in his day; he married a sister of Oliver Cromwell, and in his later years was Bishop of Chester. But his great work was the founding of the Royal Society; and his philosophical (or, as they would now be called, scientific) writings, which belong to his earlier years in London, show very clearly with what high expectations the society started on its labours. The first of these writings, published in 1638, is a discourse to prove that there may be another habitable World in the Moon. The second considers the possibility of a passage thither. The third maintains that it is probable that our Earth is one of the planets. The fourth, which is entitled Mercury; or, the Secret Messenger, discusses how thoughts may be communicated from a distance. The fifth and last, published in 1648, is called Mathematical Magic, and is divided into two books, under the titles Archimedes; or, Mechanical Powers, and Daedalus; or, Mechanical Motions. In this latter book Wilkins treats of mills, clocks, and the contrivance of motion by rarefied air; of the construction of an ark for submarine navigation, and of its uses in war; of a sailing chariot, to be driven on the land as ships are on the sea; of the possibility of perpetual motion; and, in chapters vii and viii, of the art of flying. There are four ways, according to Wilkins, whereby flying in the air may be attempted. The first is by spirits or angels; but this branch of the subject does not belong to natural philosophy. The next is by the help of fowls, which the learned Francis Bacon thought deserving of further experiment. Two ways remain of flying by our own strength; we may use wings fastened immediately to the body, or we may devise a flying chariot. If we are to use wings, he says, we must be brought up in the constant practice of them from youth, first 'running on the ground, as an ostrich or tame goose will do ... and so by degrees learn to rise higher.... I have heard it from credible testimony, that one of our own nation hath proceeded so far in this experiment, that he was able by the help of wings, in such a running pace, to step constantly ten yards at a time.' The arms of a man extended are weak, and easily wearied, so he thinks it would be worth the inquiry whether the wings might not be worked by the legs being thrust out and drawn in again one after the other, so as each leg should move both wings. But the best way of flying would be by a flying chariot, big enough to carry several persons, who might take turns to work it. Wilkins is quite honest in recognizing the difficulties of this scheme. He deals fully with the chief of them—whether so large and heavy a machine can be supported by so thin and light a body as the air; and whether the strength of the persons in it can be sufficient for the motion of it. In his attempt to show that these objections are not insuperable, he makes some true remarks. He had watched soaring birds, and had seen how they could swim up and down in the air without any sensible motion of the wings. When the right proportions of the machine are found out, and men by long practice have attained to skill and experience, we may perhaps, he thinks, be able to imitate the birds. If, after all, it be found that some greater motive power is required, we must not despair of the invention of such a power. The main difficulty will be not so much in maintaining the machine in flight as in raising it from the ground. 'When once it is aloft in the air, the motion of it will be easy, as it is in the flight of all kind of birds, which being at any great distance from the earth, are able to continue their motion for a long time and way, with little labour and weariness.' The right proportion of the wings, both for length and breadth; the special contrivances necessary for ascent, descent, or a turning motion—these and many more such questions can only be resolved, he maintains, by particular experiments. The sails of ships have been perfected by degrees, and the attempt to fly must meet with many difficulties and inconveniences for which only long experience and frequent trial can suggest a remedy.

So far Wilkins went; and he went no farther. His speculations, however, made a deep impression on his own age, gave a bias to the researches of his fellows, and, incidentally, aroused a storm of ridicule. When Joseph Glanvill, in his vigorous little treatise called Scepsis Scientifica (1665), wrote a forecast of the possible achievements of the Royal Society, he borrowed his hopes from Wilkins. 'Should these heroes go on', he says, 'as they have happily begun, they will fill the world with wonders, and posterity will find many things that are now but rumours, verified into practical realities. It may be, some ages hence, a voyage to the southern unknown tracts, yea, possibly the Moon, will not be more strange than one to America. To them that come after us it may be as ordinary to buy a pair of wings to fly into remotest regions, as now a pair of boots to ride a journey. And to confer at the distance of the Indies, by sympathetic conveyances, may be as usual to future times, as to us in a literary correspondence. The restoration of grey hairs to juvenility, and renewing the exhausted marrow, may at length be effected without a miracle; and the turning the now comparative desert world into a paradise, may not improbably be expected from late agriculture.' Again, when Sir William Temple, some thirty years later, cast contempt upon the Moderns in his Essay of Ancient and Modern Learning, it was the speculations of Wilkins that provoked his keenest satire. 'I have indeed heard of wondrous Pretensions and Visions of Men, possess'd with Notions of the strange Advancement of Learning and Sciences, on foot in this Age, and the Progress they are like to make in the next; as, the Universal Medicine, which will certainly cure all that have it; the Philosopher's Stone, which will be found out by Men that care not for Riches: the transfusion of young Blood into old Men's Veins, which will make them as gamesome as the Lambs, from which 'tis to be derived; an Universal Language, which may serve all Men's Turn, when they have forgot their own: the Knowledge of one another's Thoughts, without the grievous Trouble of Speaking: the Art of Flying, till a Man happens to fall down and break his Neck: Double-bottom'd Ships, whereof none can ever be cast away, besides the first that was made: the admirable Virtues of that noble and necessary Juice called Spittle, which will come to be sold, and very cheap, in the Apothecaries' Shops: Discoveries of new Worlds in the Planets, and Voyages between this and that in the Moon, to be made as frequently as between York and London: which such poor Mortals as I am think as wild as those of Ariosto, but without half so much Wit, or so much Instruction; for there, these modern Sages may know where they may hope in Time to find their lost Senses, preserved in Vials, with those of Orlando.'

Both Sir William Temple and Joseph Glanvill were men of acute intelligence and complete sanity; the one an aged statesman deeply versed in the deceits and follies of men; the other a young cleric, educated in the Oxford of the Commonwealth, and stirred to enthusiasm by what he had there heard of the progress of natural philosophy. In this perennial debate the man of the world commonly triumphs; he plays for the stakes that are on the table, and does not put faith in deferred gains. For something like two hundred years Sir William Temple's triumph was almost complete. Now things have changed, and Glanvill's rhapsody comes nearer to the truth. Wireless telegraphy, radium, the discoveries of bacteriology, and not least the conquest of the air, have taken the edge off the sallies of the wit, and have verified the dreams of the prophet.

What most delayed the science and art of flight, which made no progress during the whole of the eighteenth century, was an imperfect understanding of the flight of birds. The right way to achieve flight, as events were to prove, was by the study and practice of gliding. But birds were believed to support, as well as to raise, themselves in the air chiefly by what in the jargon of science is called orthogonal flight, that is, by direct downward flapping of the wings. This view received authoritative support from a famous treatise written in the seventeenth century by Giovanni Alfonso Borelli, an Italian professor of mathematical and natural philosophy. Borelli, who held professorships at the Universities of Florence and Pisa, and corresponded with many members of the Royal Society, was an older man than Wilkins, but his book on the movements of animals (De Motu Animalium), which included a section on the flight of birds (De Volatu), was not published till 1680, when both he and Wilkins were dead. It was long held in high esteem for its anatomical exposition of the action of flying, and some of its main contentions cast a damp upon the hopes of man. The bones of a bird, says Borelli, are thin tubes of exceeding hardness, much lighter, and at the same time stronger, than the bones of a man. The pectoral muscles, which move the wings, are massive and strong—more than four times stronger, in proportion to the weight they have to move, than the legs of a man. And he states his conclusion roundly—it is impossible that man should ever achieve artificial flight by his own strength. This view, dogmatically stated by one who was a good mathematician and a good anatomist, became the orthodox view, and had an enduring influence. All imitation of the birds by man, and further, all schemes of navigating the air in a machine dynamically supported, seemed, by Borelli's argument, to have been thrust back into the limbo of vanities.