The experience of Samuel Pierpont Langley in America is not unlike the experience of Ader in France and Maxim in England. He was employed by the Board of Ordnance and Fortification of the United States army to construct the “Aerodrome” of his own invention. Congress appropriated $50,000 for the purpose. Langley’s machine was a tandem monoplane, 48 feet from tip to tip, and 52 feet from bowsprit to the end of its tail. It was fitted with a 50 horse-power engine and weighed 830 pounds. The trials of this aerodrome, two attempts to launch it, were made on October 7 and December 8, 1903. On both occasions the aerodrome became entangled in the defective launching apparatus, and was thrown headlong into the Potomac River—on which the launching trials were made. Following the last failure, when the aerodrome was wrecked, the press ridiculed the whole enterprise, and Congress refused to appropriate money for further experiments. The Langley aerodrome, fitted with a Curtiss motor and Curtiss controls, flew in 1913-14.
As with experiments of the first school they did not attain practical results. The machines were usually wrecked at the first trial without giving any clew to the nature or whereabouts of the trouble. Although Langley’s machines were reconstructed and flown later this should not detract in any way from the fame of the Wright brothers, Orville and Wilbur, who really were the first to construct an aeroplane which was driven by a gasoline motor, lifting a man off the ground, and pursuing a steered and sustained flight through the air.
The experiments of Lillienthal and his death in his glider were the direct incentives to the Wright brothers to conduct their investigations with gliders. The Lillienthal way of balancing the planes by swinging his legs they judged to be a poor means of controlling the direction of the flight. So they set out to discover another method of controlling the stability of the planes. Their experiments began in the fall of 1900 at Kitty Hawk, North Carolina, as Mr. Henry Woodhouse, the aeronautical authority, has pointed out. They took all the theories of flight and tried them one by one, only to find, after two years of hard, discouraging work, that they were based more or less on guesswork. Thereupon they cast aside old theories and patiently put the apparatus through innumerable gliding tests, ever changing, adding, modifying—setting down the results; after each glide comparing, changing again and again, until they finally constructed a glider which was easy to balance both laterally and longitudinally. But in order to control fore-and-aft balance they had to eliminate Lillienthal’s method of swinging his legs and substitute a horizontal elevator. This elevator was raised and lowered by a lever operated by the pilot stretched out on the centre of the lower wing of the glider. This device kept the glider level with respect to the ground. In fact, this elevator was absolutely necessary to prevent the planes from diving up or down, for if the pilot found the glider pitching too much forward, tending to dive, he would tilt the elevator upward by means of the lever, thus pulling the nose of the glider back into its proper position. At first the Wrights built the elevator in front of the planes so that they could see and study its effect. They soon discovered that the control of the glider was much better with the elevator. This elevator has been incorporated as a standard fin on the tail of the fuselage of every aeroplane and is one of the chief factors in steering up or down.
Having completely mastered this most important step, the Wrights next took up the problem of lateral control. The natural tendency of the glider was to flop about like a kite with too light a tail. In order to correct this lateral instability the Wrights determined to make the air itself, rather than gravity, supply this balance, instead of Lillienthal’s method of swinging his legs from side to side by observing closely the way in which a pigeon secures its lateral balance by varying the angle of attack with its two wings, whereby one wing would lift more forcibly than the other, thereby turning the bird in any direction around any given axis of flight. In order to accomplish this variation the Wrights made the ends of the glider loose while the rest remained rigid. Then by a system of wires operated from a lever they could warp these wing ends of the glider, one to present a greater angle of attack to the air and the other a smaller angle, just as the pigeon did. In other words, by pulling down the rear edge of the tip of one wing and by pulling up the extreme edge of the other the angles of the wings were varied with respect to the way in which they cut through the air on very much the same principles as the tail elevator on the fuselage. Also, if a flat surface moves through the air horizontal to the ground, if you tipped the rear edge upward the air would strike it on that edge and have a tendency to force it down, thus forcing the forward edge upward. To pull it in the other direction would cause the opposite effect. The Wrights were first to incorporate this in a glider or aeroplane. They patented it, and although a hinge, called an aileron, was later attached to the end of the wings of an aeroplane to produce the same effect and at the same time to allow more rigid construction of the ends of the wings, nevertheless this idea was distinctly a Wright discovery and innovation.
Courtesy of Flying Magazine.
The Wright flyer after the epoch-making flight at Kitty Hawk, N. C., December, 1903.
This was the first successful motor-driven heavier-than-air craft to lift a man off the ground and carry him over a steered course. It had one 16 h.-p. motor with a chain-drive to two propellers. The elevators were in front of the machine. The plane resembles a glider or a box kite and the wings could be warped for steering.
But that was not all the Wright brothers did to make man-flight over a sustained and steered course in a heavier-than-air machine possible. Directional control or power to steer the glider in a straight line or to vary it had not yet been acquired, so the Wrights installed a vertical rudder which they also operated by lever, just as the rudder on a power-boat is controlled, and the effect on directional steering was the same. Indeed, passage through the medium of the air is in many ways similar to passage through water. Thus the moment the glider swerved from right to left the rudder was pulled in the opposite direction and the planes came back to the steered course.
But this was not invented at once nor installed until after the Wrights discovered that whenever the glider was in flight the effect of warping the wings to control the rolling had a serious unexpected secondary effect, namely, a tendency for the high wing, which they desired to bring down, to advance faster through the air than the low wing, and solely by its higher velocity to develop a higher lifting capacity and thus to neutralize the benefit of the warp. After much experimenting they hit upon the rudder idea and that corrected the difficulty.