Wilbur promptly saw that the explanation was probably correct and nodded approvingly. And he immediately made a suggestion. A particular relation existed, he said, in the desired pressures on the tail, no matter whether the trouble was due to difference of resistance of the wing tips or on account of sliding. Whatever the reason, it was desirable to get rid of the pressure on the side toward the low wing, to which a greater angle of incidence must be imparted in restoring lateral balance, and bring pressure on the side of the tail toward the high wing where there must be a reduced angle. So why not have the mechanism that controlled the wing warping and that which moved the tail operated in conjunction? Then the pilot, instead of having to control three things at once, would need to attend only to the front elevator and the wing-warping device. The brothers at once attached the wires controlling the tail to those that warped the wings—and they also changed the tail from two vertical fins to a single vertical rudder.
After the changes in the 1902 glider, the Wrights had their machine in about the form pictured and described in the drawings and specifications of their patent, applied for on the 23rd of the next March.
With their accurate data for making calculations, and a system of balance effective in winds as well as in calms, the brothers believed that they now could build a successful power-flyer.
VI
FIRST POWER FLIGHT
Immediately on their return to Dayton after the 1902 glider flights, the Wrights set to work to carry out plans, already begun at Kitty Hawk, for a power machine. The satisfactory performance of the glider had demonstrated the accuracy of the laboratory work on which its design was based, and they now felt sure they could calculate in advance the performance of any machine they built with a degree of accuracy not possible with the data available to their predecessors.
Early in their preparations, they took steps to obtain a suitable engine. They knew that a steam engine might do well enough for their purpose, but a gasoline engine would be simpler and better. Some time previously they had built an air-cooled, one-cylinder gas engine for operating the machinery of their small workshop; but they did not feel experienced enough to build the kind they now needed and preferred to buy one.
INSIDE THE 1902 CAMP. The kitchen corner of the 1902 camp at Kitty Hawk.
They wanted a motor to produce at least eight horsepower and to weigh, without accessories, not more than twenty pounds per horsepower. It seemed doubtful if such a motor as they required was then being manufactured; but perhaps one of the automobile companies could build one light enough by reducing the weight of the flywheel and using more aluminum than in the regular output. On December 3, 1902, they sent letters to a number of automobile companies, and to gasoline motor manufacturers, altogether to nearly a dozen, asking if they could furnish a motor that would develop eight brake horsepower and weigh not more than 200 pounds. Orville Wright was not sure in after years whether he and Wilbur revealed in their letters the use they planned for the motor they were seeking; but most of the companies replied that they were too busy with their regular business to undertake such a special order. There is reason to suspect the companies may have got wind of the purpose to which the motor would be put and were afraid to become implicated in the project. If a company provided a motor for a so-called flying-machine, and this fact should leak out, it could hurt their business prestige, because it might look as if they considered human flight a possibility.
