THE WRIGHT BROTHERS’ OWN STORY
THE Wright Brothers brought to their work a genius for invention and, making free use of the results of former investigation and experiment, finally succeeded in building a heavier than air machine which would actually fly. The story of their experiments and final success, which one may read in their own words, forms one of the most fascinating chapters in the history of invention.
The Wright Brothers’ first flying machine was a mere toy. “Late in the autumn of 1878” they tell the story, “our father came into the house one evening with some object partially concealed in his hands, and before we could see what it was, he tossed it into the air. Instead of falling to the floor, as we expected, it flew across the room till it struck the ceiling, where it fluttered for a while, and finally sank to the floor. It was a little toy known to scientists as a ‘hélicoptère’ but which we, with sublime disregard for science, dubbed a bat. It was a light frame of cork and bamboo which formed two screws driven in opposite directions by rubber bands under torsion. A toy so delicate lasted only a short time in the hands of small boys, but its memory was abiding.”
The interest of the brothers in aëronautics was awakened. “We began building these hélicoptères ourselves,” their story goes on, “making each one larger than that preceding. But, to our astonishment, we found that the larger the ‘bat,’ the less it flew. We did not know that a machine having only twice the linear dimensions of another would require eight times the power. We finally became discouraged, and returned to kite-flying, a sport to which we had devoted so much attention that we were regarded as experts. But as we became older, we had to give up this fascinating sport as unbecoming to boys of our age.”
PLATE XVII.
An Ingenious Model which Fails to Fly.
The Wrights did not begin their experiments until the summer of 1896. They first prepared themselves thoroughly by reading the literature on aëronautics, making themselves familiar with the results of all the experimental work of the aviators—Langley, Chanute, Mouillard, and others. The Wrights soon decided that the first thing to be solved was to build aëroplanes which would fly and that, until this was solved, it was foolish to waste time building delicate and costly machinery to operate them. They took up the problems of the glider and sought by actual tests what many scientists had been theorizing about for years.
They soon discarded the various forms of gliders then used for experiments. The tests which led up to adopting the now famous Wright model, the basis for all heavier than air machines to-day, occupied very little time. The story of this marvellous discovery which will rank with that of Robert Fulton or Watt, is best told in their own words, which are here somewhat abbreviated.
“The balancing of a flier may seem, at first thought, to be a very simple matter,” say the Wrights, “yet almost every experimenter had found in this the point he could not satisfactorily master. Many different methods were tried. Some experimenters place the center of gravity far below the wings in the belief that the wings would naturally seek to remain at the lowest point. A more satisfactory system, especially for lateral balance, was that of arranging the wings in the shape of a broad V to form a dihedral angle, with the center low and the wing-tips elevated. In theory this was an automatic action, but in practice it had two serious defects; first, it tended to keep the machine oscillating; and, second, its usefulness was restricted to calm air. Notwithstanding the known limitations of this principle, it had been embodied in almost every prominent flying-machine which had been built.
“We reached the conclusion that such machines might be of interest from a scientific point of view, but could be of no value in a practical way. We, therefore, resolved to try a fundamentally different principle. We would arrange the flyer so that it would not tend to right itself. We would make it as inert as possible to the effects of change of direction or speed, and thus reduce the effects of wind-gusts to a minimum. We would do this in the fore-and-aft stability by giving the aëroplanes a peculiar shape; and in the lateral balance, by arching the surfaces from tip to tip, just the reverse of what our predecessors had done. Then by some suitable contrivance, actuated by the operator, forces should be brought into play to regulate the balance.”
“Lilenthal and Chanute had guided and balanced their machines by shifting the weight of the operator’s body. But this method seemed to us incapable of expansion to meet large conditions, because the weight to be moved and the distance of possible motion were limited, while the disturbing forces steadily increased, both with wing area and wind velocity. In order to meet the needs of large machines, we wished to employ some system whereby the operator could vary at will the inclination of different parts of the wings, and thus obtain from the wind forces to restore the balance which wind itself had disturbed. This could easily be done by using wings capable of being warped, and adjustable surfaces in the shape of rudders. A happy device was discovered whereby the surfaces could be so warped that aëroplanes could be presented on the right and left sides at different angles to the wind. This, with an adjustable horizontal front rudder, formed the main features of our first glider.”
PLATE XVIII.
A Good Model Excepting that its Vertical Rudders Are Too Large.
“We began our first active experiments at the close of this period, in October, 1900, at Kitty Hawk, North Carolina. Our machine was designed to be flown as a kite, with a man on board, in winds of from fifteen to twenty miles an hour. But, upon trial, it was found that much stronger winds were required to lift it. Suitable winds not being plentiful, we found it necessary, in order to test the new balancing system, to fly the machine as a kite without a man on board, operating the levers through cords from the ground. This did not give the practice anticipated, but it inspired confidence in the new system of balance.”
“The machine of 1901 was built with the shape of surface used by Lilenthal, curved from front to rear, with a slight curvature of ⁴¹⁄₁₂ of its cord. But to make doubly sure that it would have sufficient lifting capacity when flown as a kite in fifteen or twenty mile winds, we increased the area from 165 square feet, used in 1900, to 308 square feet, a size much larger than Lilenthal, Chanute, or Pilcher had deemed safe. Upon trial, however, the lifting capacity again fell short of calculation, so that the idea of securing practice while flying as a kite, had to be abandoned. Mr. Chanute, who witnessed the experiments, told us that the trouble was not due to poor construction of the machine. We saw only one other explanation—that the tables of air pressure in general use were incorrect.”
“We then turned to gliding—coasting down hill in the air—as the only method of getting the desired practice in balancing the machine. After a few minutes’ practice we were able to make glides of 300 feet, and in a few days were safely operating in twenty-seven mile winds. In these experiments we met with several unexpected phenomena. We found that, contrary to the teachings of the books, the center of pressure on a curved surface traveled backward when the surface was inclined, at small angles, more and more edgewise to the wind. We also discovered that in free flight, when the wing on one side of the machine was presented to the wind at a greater angle than the one on the other side, the wing with the greater angle descended, and the machine turned in a direction just the reverse of what we were led to expect when flying the machine as a kite. The larger angle gave more resistance to forward motion, and reduced the speed of the wing on that side. The decrease in speed more than counterbalanced the effect of the larger angle. The addition of a fixed vertical vane in the rear increased the trouble, and made the machine absolutely dangerous. It was some time before a remedy was discovered. This consisted of movable rudders working in conjunction with the twisting of the wings.”
“The experiments of 1901 were far from encouraging. We saw that the calculations upon which all flying-machines had been based were unreliable, and that all were simply groping in the dark. Having set out with absolute faith in the existing scientific data, we were driven to doubt one thing after another, till finally, after two years of experiment, we cast it all aside, and decided to rely entirely upon our own investigations. Truth and error were everywhere so intimately mixed as to be indistinguishable. Nevertheless, the time expended in preliminary study of books was not misspent, for they gave us a good general understanding of the subject, and enabled us at the outset to avoid effort in many directions in which results would have been hopeless.”
“To work intelligently, one needs to know the effects of a multitude of variations that would be incorporated in the surfaces of flying-machines. The pressures on squares are different from those on rectangles, circles, triangles, or ellipses; arched surfaces differ from planes, and vary among themselves according to the depth of curvature; true arcs differ from parabolas, and the latter differ among themselves; thick surfaces differ from thin, and surfaces thicker in one place than another vary in pressure when the positions of maximum thickness are different; some surfaces are more efficient at one angle, others at other angles. The shape of the edge also makes a difference, so that thousands of combinations are possible in so simple a thing as a wing.”
PLATE XIX.
A Simple Cellular Form.
“We had taken aëronautics merely as a sport. We reluctantly entered upon the scientific side of it. But we soon found the work so fascinating that we were drawn into it deeper and deeper. Two testing machines were built, which we believed would avoid the errors to which the measurements of others had been subject, after making preliminary measurements on a great number of different-shaped surfaces, so varied in design as to bring out the underlying causes of difference noted in their pressure. Measurements were tabulated on nearly fifty of these at all angles from zero to 45 degrees.
“In September and October, 1902, nearly one thousand flights were made, several of which covered distances of over 600 feet. Some, made against a wind of thirty-six 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, after 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.”
“With accurate data for making calculations, and a system of balance effective in winds as well as in calms, we were now in a position, we thought, to build a successful power-flyer. The first designs proved for a total weight of 600 pounds, including the operator and an eight horsepower motor. But, upon completion, the motor gave more power than had been estimated, and this allowed 150 pounds to be added for strengthening the wings and other parts.
“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 suitable propellers, with proper diameter, pitch, and area of blade, to meet the requirements of the flyer. 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 and Langley.”
“The first flights with the power-machine were made on the 17th of December, 1903. The first flight lasted only twelve seconds, a flight very modest compared with that of birds, but it was, nevertheless, the first in the history of the world in which a machine carrying a man had raised itself by its own power into the air in free flight, had sailed forward on a level course without reduction of speed, and had finally landed without being wrecked. The second and third flights were a little longer, and the fourth lasted fifty-nine seconds, covering a distance of 853 feet over the ground against a twenty-mile wind.”
“After the last flight, the machine was carried back to camp and set down in what was thought to be a safe place. But a few minutes later, when engaged in conversation about the flights, a sudden gust of wind struck the machine, and started to turn it over. All made a rush to stop it, but we were too late. Mr. Daniels, a giant in stature and strength, was lifted off his feet, and falling inside, between the surfaces, was shaken about like a rattle in a box as the machine rolled over and over. He finally fell out upon the sand with nothing worse than painful bruises, but the damage to the machine caused a discontinuance of experiments.
PLATE XX.
A Cellular Type with Rudder and Elevating Plane.
“In the spring of 1904, through the kindness of Mr. Torrence Huffman of Dayton, Ohio, we were permitted to erect a shed, and to continue experiments, on what is known as the Huffman Prairie, at Simms Station, eight miles east of Dayton. The new machine was heavier and stronger, but similar to the one flown at Kitty Hawk. When preparations had been completed, a wind of three or four miles 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 in the air at all. Several of the newspaper men returned the next day, but were again disappointed. The engine performed badly, and after a glide of only sixty feet, the machine came to the ground. Further trial was postponed till the motor could be put in better running condition.
“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 flight, it could have been righted in an instant. In one flight, in 1905, while circling about a honey-locust tree at a height of about fifty 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 ten or twelve feet from the ground, and carried away several branches; but the flight, which had 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 the 5th of October.
“A practical flyer having been finally realized, we spent the years 1906 and 1907 in constructing new machines and in business negotiations. It was not till May of this year (1908) that experiments were resumed at Kill Devil Hill, North Carolina. The recent flights were made to test the ability of our machines to meet the requirements of a contract with the United States Government to furnish a flier capable of carrying two men and sufficient fuel supplies for a flight of 125 miles, with a speed of forty miles an hour. The machine used in these tests was the one with which the flights were made at Simms Station in 1905, though several changes had been made to meet present requirements. The operator assumed a sitting position, instead of lying prone, as in 1905, and a seat was added for a passenger. A larger motor was installed, and radiators and gasolene reservoirs of larger capacity replaced those previously used.”
PLATE XXI.
A Complicated Model Capable of Long Flights.
Let us now take a short air journey with one of the Wright Brothers as pilot. He describes the experience as follows, “Let us fancy ourselves ready for the start. The machine is placed on a single rail track facing the wind and is securely fastened with a cable. The engine is put in motion, and the propellers in the rear whirr. You take your seat at the center of the machine beside the operator. He slips the cable, and you shoot forward. An assistant who has been holding the machine in balance on the rail, starts forward with you, but before you have gone fifty feet the speed is too great for him, and he lets go. Before reaching the end of the track the operator moves the front rudder, and the machine lifts from the rail like a kite supported by the pressure of the air underneath. The ground under you is at first a perfect blur, but as you rise the objects become clearer. At a height of one hundred feet you feel hardly any motion at all, except for the wind which strikes your face. If you did not take the precaution to fasten your hat before starting, you have probably lost it by this time. The operator moves a lever; the right wing rises and the machine swings about to the left. You make a very short turn, yet you do not feel the sensation of being thrown from your seat, so often experienced in automobile and railway travel. You find yourself facing toward the point from which you started. The objects on the ground seem to be moving at much higher speed, though you perceive no change in the pressure of wind in your face. You know then that you are traveling with the wind. When you near the starting point, the operator stops the motor while still high in the air. The machine coasts down at an oblique angle to the ground, and after sliding fifty or a hundred feet, comes to rest. Although the machine often lands when traveling at a speed of a mile a minute, you feel no shock whatever, and cannot in fact, tell the exact moment at which it first touched the ground. The motor close beside you kept up an almost deafening roar during the whole flight, yet in your excitement, you did not notice it till it stopped.”
On his return from Le Mans Mr. Wilbur Wright estimated that during a single year he had flown upwards of 3000 miles. With the memory of these marvellous flights in his mind he described his sensations to the present writer with enthusiasm.
“Flying is the greatest sport in the world,” says Mr. Wilbur Wright. “I can’t describe the sensation, I can only define it by comparison with more familiar experiences. It is like sledding, like motoring, like sailing, but with increased exhilaration and freedom.
“An aëroplane flight, contrary to the general impression, is far steadier than the familiar means of locomotion. There is absolute freedom from the bouncing of the automobile, the jar of a railroad train, or the rolling and pitching sensations of the sea. No matter how many springs or cushions may be added to the automobile, for instance, there will always be some motion. On the other hand, the seat of an aëroplane is always steady. The aëroplane does not jolt over the invisible wind currents, the ruts of the sky. It cuts its way smoothly. Even suppose the plane to be gliding so (indicating an angle of forty-five degrees), the seat remains fixed. There is, of course, no absolute parallel in surface travel. And since there is no roll or pitch to the aëroplane, there is no air-sickness comparable to the familiar sea sickness.”