The Wright brothers had begun their aeronautical experiments over three years earlier to develop a system of aerodynamic controls for an airplane. The most successful glider designers to date, Otto Lilenthal and Octave Chanute, used weight-shifting as a means to balance their aircraft in the air. Not only was this system crude and inexact, it was limiting. A human pilot only weighed so much, and shifting his weight had less and less effect on the attitude of the airplane the larger it became. Because of this, both Lilienthal and Chanute had determined that the maximum wingspan for a glider should be no more than 12 feet.

The Wrights broke that rule from the very beginning. Their first man-carrying glider, which they tested at Kitty Hawk in 1900, had a wingspan of 17 feet. It would have been 19, but Wilbur could not find the lengths of lumber he needed in North Carolina lumberyards to make long spars. It had aerodynamic controls for two axes - a forward elevator to control pitch and a unique system of cables that warped the wings to roll the aircraft. The 1900 glider had responded well to its controls, but it did not produce enough lift to support a 150-pound pilot unless flown in a relative wind of 26 miles per hour - a speed that the Wright brothers considered much too fast to be safe.

The Wrights figured that the glider did not produce the necessary lift because it didn�t have enough wing area. So they came back to Kitty Hawk again in 1901 with a larger machine. The wings of the 1901 Wright Glider spanned 22 feet and had a chord of 7 feet - 2 feet fatter than their previous glider. It was a disappointment all they way around. Not only did it produce insufficient lift, but also the fat wings made it less responsive to the controls. The brothers cut short their experiments and left Kitty Hawk with Wilbur declaring that man might someday fly, but probably "not in a thousand years."

Back home in Dayton, Ohio, they took a more objective look at their experiments to date. In designing both the 1900 and 1901 gliders, they had relied on data developed by other experimenters, especially Otto Lilienthal and Samuel Langley (the head of the Smithsonian Institution, who was build powered aircraft). They suspected that the lift tables developed by these men for various wing shapes were too optimistic. So the Wrights built a small wind tunnel and painstakingly put together their own lift tables, testing 200 wing shapes. Then they used this data to design their 1902 glider.

The 1900 Wright Glider had an elevator to control pitch and wing warping to control roll, but there was no way to control yaw.

The same was true of the 1901 glider -- it had roll and pitch controls only.

The 1902 Wright Glider was the first Wright flying machine that actually looked like an aircraft. It had long, slender wings, spanning 32 feet but with a chord of just 5 feet. It was longer, too. The brothers placed the front elevator further out in front of the wings to give it more leverage. And for the first time, they added a vertical tail behind the wings, thinking that this might cure the curious problems they had experienced in the 1901 glider when they tried to turn in the air. The glider would roll in one direction, but turn in the other. The tail was meant to keep the glider moving in the proper direction.

Pilots have a grammatically incorrect saying, "If it looks good, it flies good." This certainly seemed to be the case with the 1902 glider. It was the first Wright flying machine that produced adequate lift. More important, it was their first machine where the predicted amount of lift matched the lift they measured in test flights. And they seemed to have ample control. The glider responded well to adjustments they made in flight with the elevator and wing warping. They were very, very close to achieving controlled flight.

But they could not turn the aircraft in the air with any assurance. If the bank became too steep, the aircraft would roll in one direction while the wings swung in the opposite direction. If they didn�t roll out immediately, the lower wing would stall, the higher wing would shoot up, and the aircraft would auger into the ground in a frightening maneuver Will and Orv termed "well-digging."

It was this problem that Orville thought through during that sleepless night in October of 1902. The Wright wind tunnel tests had shown that as the wing angle of attack increased so did the lift. But the drag (which the Wrights called "drift") also increased. When the pilot warped the wings of the 1902 glider, the angle of attack increased on one side of the pilot and decreased on the other. This was supposed to roll the airplane so it would bank into a turn, just as a bicycle or a bird banks when turning. However, reasoned Orville, warping the wings also increased the drag on the side producing the most lift, causing the aircraft to yaw in the opposite direction of the turn. Maybe the thing to do was to balance the drag forces by creating an equal amount of drag on both sides of the pilot.

With a fixed tail, the 1902 glider few well in straight and level flight. But it gave the brothers fits when they tried to turn it. They would lose control and glider would spin into the sand.

We�ve all had those epiphanies when, in studying out a problem, the solution suddenly arrives full-blown in your head and nearly knocks you over with its simplicity. Engineers call this the "elegant solution." The result is good science, but the experience is as inspiring as great poetry. This is what happened to Orville sometime during that night. The solution was simply to convert the fixed tail into a movable rudder. When the pilot rolled in one direction, he would swing the tail in the same direction to create additional drag on that side of the aircraft. This would balance the increased drag on the opposite side and counteract what is known today as adverse yaw. Good science, great poetry, behold the birth of Aviation.

When Orville explained his epiphany to Wilbur on the morning of October 3, he expected an argument. Wilbur customarily adopted the attitude of the older, wiser brother whenever Orville made a suggestion and the two would hash it out in an energetic argument. But for once, Wilbur acquiesced. The solution felt so right there was just no arguing with it. The two got to work adapting the tail to swing right and left.

On October 8, 1902, the Wright brothers took their modified glider out for a test flight. In this new configuration, the glider was the first recorded machine in history with 3-axis control - roll, pitch, and yaw. If you go to the little museum there at Kitty Hawk, Ranger Darell Collins gives an inspiring speech which he begins with, "Before the Wright brothers, no one in aviation did anything correct. Since the Wright brothers, no one has done anything different." This is what he is talking about. Since the time of the Wright brothers, every successful flying machine has had roll, pitch, and yaw controls. It is a fundamental concept not just in aeronautical design, but also submarine navigation, spacecraft control, and robotics. All those engineering disciplines can trace their roots back to the first trial flights of the 1902 Wright Glider on October 8, 1902.

You may think I�m making too much of this glider. After all, the Wrights are best remembered for their first powered flights on December 17, 1903. But if you look up what Federal Courts upheld as the grandfather patent of the airplane, United States Patent Number 891,393 granted to O. & W. Wright on May 23, 1906, you will find engineering drawings not of the 1903 Wright Flyer, but the 1902 Wright Glider. And the focus of that patent has nothing to do with power and everything to do with control. The 1902 glider is the great-granddaddy of everything that flies.

In this new configuration, the glider could be turned safely in the air. It was the first machine in history with 3-axis control -- roll, pitch, and yaw.

The Wright Patent -- the grandfather patent of the aircraft -- shows the 1902 Wright Glider, not a powered airplane. The most important contribution that the Wrights made to aviation was the development of a 3-axis control system and the skills necessary to us them effectively.