It is not in mortals to command success; but those who study the record of the ingenious, persevering, and helpful work done for a quarter of a century by Mr. Laurence Hargrave, of Sydney, New South Wales, will agree with Mr. Chanute that this man deserved success. His earliest important paper was read to the Royal Society of New South Wales in 1884. In the course of the next ten years he made with his own hands eighteen different flying machines, of increasing size, all of which flew. His earlier machines were not much larger than toys, and were supplied with power by the pull of stretched india-rubber. On this scale he was successful with a machine driven by an airscrew and with a machine driven by the flapping of wings. As his machines grew in size he turned his attention to engines. He was successful with compressed air; he made many experiments with explosion motors; and he succeeded in producing a steam-engine which weighed seven pounds and developed almost two-thirds of one horse-power. In 1893 he invented the box-kite, which is a true biplane, with the vertical sides of the kite doing the work of a stabilizing fin. This kite had a marked influence on the design of some early flying machines. He also invented the soaring kite. His hope that man would fly was more than hope; he refused to argue the question with objectors, for 'I know', he said, 'that success is dead sure to come'. Moreover he put all his researches at the disposal of others. He refused to take out any patents. He did all he could to induce workers to follow his example and communicate their ideas freely, so that progress might be quickened. His own ideas, his own inventions, and his own carefully recorded experiments were a solid step in that staircase of knowledge from which at last man launched himself into the air, and flew.
In America the pioneer who did most to further the science of human flight was Professor Samuel Pierpont Langley, of the Smithsonian Institute, in Washington. He was well known as an astronomer before ever he took up with aeronautics. From 1866 to 1887 he was professor of astronomy at the Western University of Pennsylvania, at Pittsburg. During his later years there he built a laboratory for aerial investigations, and carried out his famous experiments. His whirling table, with an arm about thirty feet long, which could be moved at all speeds up to seventy miles an hour, was devised to measure the lifting power of air resistance on brass plates suspended to the arm. In 1891 he published his Experiments in Aerodynamics, which embodied the definite mathematical results obtained by years of careful research. It would be difficult to exaggerate the importance of this work. The law which governs the reaction of the air on planes travelling at various speeds and various angles of incidence had been guessed at, or seen in glimpses, by earlier investigators; but here were ascertained numerical values offered to students and inventors. The main result is best stated in Professor Langley's own words: 'When the arm was put in motion I found that the faster it went the less weight the plates registered on the scales, until at great speed they almost floated in the air.... I found that only one-twentieth of the force before supposed to be required to support bodies under such conditions was needed, and what before had seemed impossible began to look possible.... Some mathematicians, reasoning from false data, had concluded that if it took a certain amount of power to keep a thing from falling, it would take much additional power to make it advance. My experiment showed just the reverse ... that the faster the speed the less the force required to sustain the planes, and that it would cost less to transport such planes through the air at a high rate of speed than at a low one. I found further that one horse-power could carry brass plates weighing two hundred pounds at the rate of more than forty miles an hour in horizontal flight.'
When these researches were known and understood, their effect upon the practical handling of the problem of flight was immediate and decisive. The aeroplane, or gliding machine, had many rivals; they were all killed by Professor Langley's researches, which showed that the cheapest and best way to raise a plane in the air is to drive it forward at a small upward inclination; and that its weight can be best countered not by applying power to raise it vertically, but by driving it fast. In the statistical tables that he prepared he called the upward pressure of the air Lift; the pressure which retards horizontal motion he called Drift. The words make a happy pair, but the word Drift is badly needed to describe the leeway of an aeroplane in a cross-wind, so that in England another pair of words, Lift and Drag, has been authoritatively substituted.
From this time onward Langley devoted himself to those other problems, especially the problems of balance, of mechanical power, and of safety in taking off and alighting, which had to be solved if he was to make a machine that should fly. He was much influenced, he says, by a mechanical toy, produced as early as 1871 by an ingenious Frenchman called Penaud, and named by its inventor the 'planophore'. This toy, which weighed only a little over half an ounce, was supported on wings, and was driven forward by an airscrew made of two feathers. The motive power was supplied by twisted strands of rubber which, as they untwisted, turned the airscrew. The wings were set at a dihedral angle, that is, they were bent upwards at the tips; and fore-and-aft stability was secured by a smaller pair of wings just in front of the airscrew. 'Simple as this toy looked,' says Professor Langley, 'it was the father of a future flying machine, and France ought to have the credit of it.' His own steam-driven flying machine was produced and successfully flown in 1896. It had two wings and a tail, with a supporting surface in all of seventy square feet; its total weight was seventy-two pounds; the engine, constructed by himself, weighed only seven pounds and developed one horse-power, which served to drive two airscrews, revolving in opposite directions. The best flight of this machine was more than three-quarters of a mile, and was made over the Potomac river. When, on its first flight, it had flown for a minute, 'I felt', says Professor Langley, 'that something had been accomplished at last, for never in any part of the world or in any period had any machine of man's construction sustained itself in the air before for even half of this brief time'. His flying machines were called by Langley 'aerodromes', and the word 'aeroplane' was used by him, as it is used in the New English Dictionary of 1888, only in the sense of a single plane surface used for aerial experiments. But no usage, however authoritative, can withstand the tide of popular fashion; the machine is now an aeroplane, while aerodrome is the name given to the flying-ground from which it starts.
The success of his machine became widely known, and in 1898 the War Department of the United States, having ascertained that Langley was willing to devote all his spare time to the work, allotted fifty thousand dollars for the development, construction, and test of a large 'aerodrome', big enough to carry a man. The construction was long delayed by the difficulty of finding a suitable engine. This difficulty hampered all early attempts at flight. The internal-combustion engine was by this time pretty well understood, and, with the will to do it, might have been made light enough for the purpose. But it was almost an axiom with engineering firms that a very light engine could not wear well and was untrustworthy in other ways. One horse-power to the hundredweight was what they regarded as the standard of solid merit. Further, they were prejudiced against that extremely rapid movement of the parts which is necessary if the crank-shaft is to revolve more than a thousand times a minute. They were asked to depart from all their cherished canons and to risk failure and break-down in order that man should achieve what many of them regarded as an impossibility. It was with Langley as it was with Pilcher and the Wrights; he had to make his own engine. By 1901 he had completed with the aid of his assistants an engine of fifty-two horse-power, weighing, with all its appurtenances, less than five pounds to the horse-power. A year and a half more was spent in adapting and co-ordinating the frame and appliances, and in carrying out the shop tests. At last, on the 7th of October 1903, from a house-boat moored in the Potomac river, about forty miles below Washington, the first trial was made. The machine caught in the launching mechanism, and fell into the river, where it broke. It was repaired, and a second trial was made on the 8th of December 1903. Again the machine failed to clear the launching car, and plunged headlong into the river, where the frame was broken by zealous efforts to salve it in the dark. Nine days after this final failure the Wrights made their first successful power-driven flight, at Kitty Hawk, on the coast of North Carolina.
Langley was almost seventy years old when his last and most ambitious machine failed. He lived for two years more. If his contributions to the science of flight, which are his chief title to fame, were ruled out of the account, he would still be remembered as something more than a good astronomer—a man of many sciences, who cared little for his own advancement, and much for the advancement of knowledge.
From what has been said it is now possible to conceive how things stood when the brothers, Wilbur and Orville Wright, first attacked the problem of flying in the air. Men had flown, or rather had glided through the air, without engines to support and drive them. Machines had flown, without men to control and guide them. If the two achievements could be combined in one, the problem was solved; but the combination, besides bringing together both sets of difficulties and dangers, added new dangers and difficulties, greater than either. Plainly, there were two ways, and only two, of going about the business. Professor Langley held that in order to learn to fly, you must have a flying machine to begin with. Wilbur Wright, whose views on the point never varied from first to last, held that you must have a man to begin with. The brothers were impatient of 'the wasteful extravagance of mounting delicate and costly machinery on wings which no one knew how to manage'. When they began their experiments they had already reached the conclusion that the problem of constructing wings to carry the machine, and the problem of constructing a motor to drive it, presented no serious difficulty; but that the problem of equilibrium had been the real stumbling-block, and that this problem of equilibrium was the problem of flight itself. 'It seemed to us', says Wilbur Wright, '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 practise by the hour instead of by the second there would be hope of advancing the solution of a very difficult problem.'
When this was written, in 1901, it was a forecast; it is now the history of a triumph. By prolonged scientific practice, undertaken with every possible regard to safety, on soaring and gliding machines, the Wrights became master pilots and conquerors of the air. Their success had in it no element of luck; it was earned, as an acrobat earns his skill. So confident did they become that to the end their machines were all machines of an unstable equilibrium, dependent for their safety on the skill and quickness of the pilot. Their triumph was a triumph of mind and character. Other men had more than their advantages, and failed, where these men succeeded. Great things have sometimes been done by a happy chance; it was not so with the Wrights. They planned great things, and measured themselves against them, and were equal to them.
Wilbur and Orville Wright were the sons of Milton Wright, of Dayton, Ohio. They came of New England stock. One of their ancestors emigrated from Essex in 1636, and settled at Springfield, Massachusetts; a later ancestor moved west, to Dayton. Wilbur was born in 1867, and Orville in 1871. They had two elder brothers and one younger sister; but Wilbur and Orville were so closely united in their lives and in their thoughts, that it is not easy to speak of them apart. Mr. Griffith Brewer, who knew them both, was often asked which of the two was the originator, and would reply, 'I think it was mostly Wilbur'; but would add, 'The thing could not have been done without Orville'. Wilbur, being four years the elder, no doubt took the lead; but all their ideas and experiments were shared, so that their very thought became a duet. Wilbur, who died in 1912, was a man of a steady mind and of a dominant character, hard-knit, quiet, intense. He has left some writings which reflect his nature; they have a certain grim humour, and they mean business; they push aside all irrelevance, and go straight to the point. After adventures in printing and journalism the two brothers set up at Dayton as cycle manufacturers. The death of Lilienthal, reported in the newspapers in 1896, first called their attention to flight, and they began to read all available books on the subject. They found that an immense amount of time and money had been spent on the problem of human flight—all to no effect. Makers of machines had abandoned their efforts. As for gliders, after the death of Lilienthal, Mr. Chanute had discontinued his experiments, and, a little later, Mr. Pilcher fell and was killed. When knowledge of these things came to the brothers, it appealed to them like a challenge. From 1899 onwards they turned all their thoughts to the problem. They watched the flight of birds to see if they could surprise the secret of balance. They studied gliding machines, and resolved to construct a machine of their own, more or less on the model of Mr. Chanute's most successful glider, which was a biplane, or 'double-decker'. When their machine was partly built, they wrote to the weather bureau at Washington, and learned that the strongest and most constant winds were to be found on the coast of North Carolina. They then wrote to the postmaster of Kitty Hawk, who testified that the sand-hills of that place were round and soft, well fitted for boys playing with flying machines. They took the parts of their machine to Kitty Hawk, assembled and completed it in a tent, and forthwith began their long years of continuous and progressive experiment. Their chief helper was Mr. Chanute. 'In the summer of 1901', they said, 'we became personally acquainted with Mr. Chanute. When he learned that we were interested in flying as a sport and not with any expectation of recovering the money we were expending on it, he gave us much encouragement. At our invitation he spent several weeks with us at our camp at Kill Devil Hill, four miles south of Kitty Hawk, during our experiments of that and the two succeeding years.'
The first two summers, 1900 and 1901, brought them some familiarity in the handling of their first two gliders, which they navigated lying face downward on the lower plane. In all their gliding experiments they studied safety first. They knew that the business they had embarked on was of necessity a long and dangerous one; that they were bound to encounter many dangers, and that each of them had only one life. They took no avoidable risks. Gliding seemed to them, at first, to have been discredited by the deaths of Lilienthal and Pilcher, so they planned to try their machine by tethering it with a rope and letting it float a few feet from the ground, while they practised manipulation. The wind proved to be not strong enough to sustain the weighted machine, and they were compelled to take to gliding. All their early glides were made as near the ground as possible. The machine had no vertical rudder, but they fitted it, in front, with what they called a horizontal rudder, that is, an elevator. By the use of this they could bring it to the ground at once when the wind was tricky and their balance was threatened. The lateral balance they attempted to control by warping the wings, but with no satisfactory results. They made glides longer than any on record, but while the problem of stability was still unsolved, there could be no real progress. At the end of 1901, Wilbur Wright made the prediction that men would some time fly, but that it would not be in their lifetime.