In his letter to the Smithsonian, Wilbur had made mention of his interest in birds. To achieve human flight, he had written, was “only a question of knowledge and skill in all acrobatic feats,” and birds were “the most perfectly trained gymnasts in the world . . . specially well fitted for their work.”
Among the material the Smithsonian provided him was an English translation of a book titled L’Empire de l’Air, published in Paris in 1881. It had been written by a French farmer, poet, and student of flight, Louis Pierre Mouillard. Nothing Wilbur had yet read so affected him. He would long consider it “one of the most remarkable pieces of aeronautical literature” ever published. For Wilbur, flight had become a “cause,” and Mouillard, one of the great “missionaries” of the cause, “like a prophet crying in the wilderness, exhorting the world to repent of its unbelief in the possibility of human flight.”
At the start of his Empire of the Air, Mouillard gave fair warning that one could be entirely overtaken by the thought that the problem of flight could be solved by man. “When once this idea has invaded the brain, it possesses it exclusively.”
That said, Mouillard moved on to the miracle of flying creatures, writing with unabashed evangelical fervor.
Oh, blind humanity! Open thine eyes and thou shalt see millions of birds and myriads of insects cleaving the atmosphere. All these creatures are whirling through the air without the slightest float [support]; many of them are gliding therein, without losing height, hour after hour, on pulseless wings without fatigue; and after beholding this demonstration given by the source of all knowledge, thou wilt acknowledge that aviation is the path to be followed. . . .
By merely observing with close attention how the winged tribes perform their feats, by carefully reflecting on what we have seen, and, above all, by striving correctly to understand the modus operandi of what we do see, we are sure not to wander far from the path, which leads to eventual success.
It was only necessary to have “good eyes,” and know how to keep in sight, with telescope or field glasses, a bird going at full speed, but still more “to know what to look at.”
Wilbur had taken up bird-watching on a rugged stretch along the banks of the Miami River south of town called the Pinnacles. On Sundays he would ride off on his bicycle to spend considerable time there observing as Mouillard preached.
Mouillard had spent much of his life in Egypt and Algeria, where he came to love especially the great soaring vultures of Africa. He had observed them by the thousands, yet however often he saw one fly high overhead, he could not help following it with a feeling of wonderment.
He knows how to rise, how to float . . . to sail upon the wind without effort . . . he sails and spends no force . . . he uses the wind, instead of his muscles.
This, Mouillard said, was the way of flight that would “lead men to navigate the immensity of space.”
III.
For Wilbur and Orville the dream had taken hold. The works of Lilienthal and Mouillard, the brothers would attest, had “infected us with their own unquenchable enthusiasm and transformed idle curiosity into the active zeal of workers.”
They would design and build their own experimental glider-kite, drawing on much they had read, much they had observed about birds in flight, and, importantly, from considerable time thinking. They had made themselves familiar with the language of aeronautics, the terms used in explaining the numerous factors involved in attaining “equilibrium” or balance in flight, where balance was quite as crucial as in riding a bicycle. Lift came from air moving faster over the arched top of a wing, thereby making the pressure there less than that under the wing. Pitch was the lateral tilt of the flying machine, front and back, nose down, nose up. Roll applied to the rotation of the wing, up or down on one side or the other, like a boat rocking. Yaw applied to the direction of the flight, the turning of the plane pointing the nose left or right.
Equilibrium was the all-important factor, the brothers understood. The difficulty was not to get into the air but to stay there, and they concluded that Lilienthal’s fatal problem had been an insufficient means of control—“his inability to properly balance his machine in the air,” as Orville wrote. Swinging one’s legs or shifting the weight of one’s body about in midair were hardly enough.
Wilbur’s observations of birds in flight had convinced him that birds used more “positive and energetic methods of regaining equilibrium” than that of a pilot trying to shift the center of gravity with his own body. It had occurred to him that a bird adjusted the tips of its wings so as to present the tip of one wing at a raised angle, the other at a lowered angle. Thus its balance was controlled by “utilizing dynamic reactions of the air instead of shifting weight.”
The chief need was skill rather than machinery. It was impossible to fly without both knowledge and skill—of this Wilbur was already certain—and skill came only from experience—experience in the air. He calculated that in the five years Lilienthal had devoted to gliders and gliding, he spent a total of only five hours in actual flight. It was hardly enough and not how he and Orville would proceed.
On an evening at home, using a small cardboard box from which he had removed the ends, Wilbur put on a demonstration before Orville, Katharine, and a visiting Oberlin classmate, Harriet Silliman. He showed them how, by pressing the opposite corners of the box, top and bottom, the double wings of a biplane glider could be twisted or “warped,” to present the wing surfaces to the air at different angles or elevations, the same as the birds did. Were one wing to meet the wind at a greater angle than the other, it would give greater lift on that side and so the glider would bank and turn.
With “wing warping,” or “wing twisting,” as it was sometimes referred to, Wilbur had already made an immensely important and altogether original advance toward their goal.
IV.
In the summer of 1899, in a room above the bicycle shop on West Third Street, the brothers began building their first aircraft, a flying kite made of split bamboo and paper with a wingspan of five feet. It was a biplane, with double wings, one over the other, the design Octave Chanute used for his gliders and that was believed to provide greater stability. The wings were joined in the fashion of a bridge truss, with vertical struts of pine and crisscrossing wires. Also included was an original system of cords whereby the operator on the ground, using sticks held in both hands, could control the wing warping.
In early August, Wilbur tested the model in an open field outside of town. Orville, for some reason, had been unable to attend. A few small boys were the only witnesses.