Success! Orville's and Wilbur's 1902 Glider Flights
By the beginning of 1902, Orville and Wilbur Wright were confident they were correct in their aerodynamic calculations and wing designs. The brothers returned to Kill Devil Hills on August 27, 1902, and spent their first week there repairing the aircraft hangar and setting up camp. They then began to assemble their new machine.
Based on their wind tunnel data, their 1902 glider had a new wing with a shallow camber and high aspect ratio. It was a major departure from their earlier machines. It had roughly the same wing surface area as the 1901 machine, but the similarities ended there. The wingspan was ten feet (three meters) longer and the chord two feet (0.6 meter) shorter than the old machine, making the glider look larger and more graceful. It had an overall length of 16 feet (5 meters) and weighed 112 pounds (51 kilograms). The wing camber followed a shallow parabolic curve, and the elevator was extended farther out in front of the pilot. This gave it more leverage, which allowed better control. The 1902 glider also had a new rudder that consisted of two fixed vertical surfaces located behind the aircraft . Wilbur and Orville calculated that these would help prevent the skidding that had occurred when they warped the wings.
After adjusting the wing trussing to provide more stability in a crosswind, they began their tests on September 19. From the first test flight as a kite, it was evident their new glider was vastly superior to their two previous machines. The amount of lift produced by the new wing design was very close to what the brothers had predicted. Within a few weeks, they were making glides of more than 500 feet (152 meters).
Both brothers spent most of the 1902 flying season learning to become pilots. Orville flew for the first time and the two practiced gliding until they became equally proficient in controlling the aircraft's balance. The athletic skills they had developed in bicycle riding helped with this task. As Wilbur had done with earlier machines, Orville smashed up the glider in a spectacular crash, resulting in “a heap of flying machine, cloth, and sticks…with me in the center without a scratch or a bruise.” But it took more than a crash to discourage the brothers at this pointthey put the glider back together and continued to fly.
One problem persisted. The glider still slipped in turns. The tail did little to stop it; in fact, Orville suspected it made the problem worse. When the wings were warped and the plane began to turn, the set of wings inside the turn was moving slower (and therefore generating less lift) than the wings on the outside. At the same time, the fixed tailno longer parallel to the air stream–presented a broad surface that dragged in the air, increased the skid, and further slowed the inside wings. The wings dropped as they lost more and more lift, and the glider went into an uncontrolled spiral and struck the ground. The brothers called this “well-digging.” Orville determined that they could avoid “well digging” if the fixed tail was changed into a movable rudder with its own separate control. This would allow the pilot to adjust its angle during a turn to overcome the drag from the high wing, keep the inside wing from losing too much lift and prevent the aircraft from skidding. Wilbur accepted the idea but suggested the pilot already had enough to do without the addition of another control. Instead, the brothers coupled the wires that turned the rudder with the wing warping mechanism. On October 6, 1902, they replaced the double rudder with a single movable rudder.
They had finally solved three-dimensional control. The movable rudder, which had an area of 5.7 square feet (0.5 square meter), made the 1902 Wright glider the first aircraft capable of being precisely balanced in flight. The elevator controlled pitch, turning the glider's nose up or down. The wing warping controlled roll , raising or lowering a wing; and the rudder controlled yaw, moving the nose left or right.
This glider was the world's first aircraft with three-axis controlcontrol around the longitudinal, lateral, and vertical axesand was the heart of the Wrights' first pioneer “flying machine” patent. This breakthrough was so basic every aircraft and spacecraft flying today still use the same fundamental controls of roll, pitch, and yaw first developed by the Wright brothers.
Wilbur's and Orville's brother Lorin arrived for a visit in September and took many of the photographs that are now famous. Octave Chanute and George Spratt also visited the brothers in September and October along with another of Chanute's aeronautical acquaintances, Augustus Herring. Herring was the co-designer and builder of Chanute's 1896 biplane glider. He brought an altered version of that craft with him. He attempted to fly it, but it was a humiliating failure, barely able to glide 50 feet (15 meters). Herring left after a few days, understandably jealous of the Wright's success. The remaining visitors helped the brothers launch their craft again and again, sometimes making more than 100 flights in a single day.
Altogether, the brothers flew their glider almost 1,000 times during September and October. The best flying came in late October, after all the visitors had left. Wilbur made a glide covering 622 feet (190 meters) with a duration of 26 seconds; Orville's best was 615 feet (187 meters), staying aloft just over 21 seconds.
Wilbur wrote: “…In the last ten days of practice we crowded in more glides than in all of the weeks preceding. In two days we made about two hundred and fifty, all of which were made in winds ranging from 9 to 16-3/4 meters per second [29.5 to 55 feet per second]. The duration of these glides ranged from seven to sixteen seconds. This practice enabled us to very greatly increase our skill in the management of the machine. We increased our record for distance to 622.5 feet [190 meters], for a time of twenty-six seconds, and for angle to 5 degrees for a glide of 156 feet [47.5 meters].”
They returned home to Dayton on October 28, ready for the next step, powered flight. They had solved the key problems of flight: the lifting ability of the wings and the perfection of three-dimensional control. The 1902 glider was, for all practical purposes, the first true airplane. It was this machine that would form the basis of their 1906 patent. All that was now needed for powered flight was a propeller and an engine.