Orville was the born engineer, Wilbur the visionary.

The brothers' partnership started after a hockey accident seriously injured 18-year-old Wilbur, leaving him in a state of depression for nearly two years. Younger brother Orville, who "was always very optimistic," as their grand-nephew, Wick Wright, tells THE AMERICAN EXPERIENCE, finally coaxed Wilbur out of the house and into his printing business.

By 1892, Orville and Wilbur had opened a bicycle shop. The bicycle had become a national craze and represented the cutting edge in technology. The shop was the perfect laboratory for the Wrights to develop engineering skills, and the brothers were soon hand-crafting their own. But they grew restless and Wilbur, now 30, was anxious to make his mark in the world. "The boys of the Wright family are all lacking in determination and push," he lamented in a letter. "None of us has, as yet, made particular use of the talent in which he excels other men."

Wilbur and Orville followed with interest the progress of the world's inventors like American Samuel Langley and German Otto Lillienthal, who were trying to develop a flying machine. In a letter to Langley, director of the Smithsonian Institution, Wilbur wrote, "I believe that simple flight at least is possible to man. I am an enthusiast, but not a crank. I wish to avail myself of all that is already known and then if possible add my bit." Wilbur had no trouble convincing Orville to work with him on the invention.

The brothers reasoned that flight depended on three concepts: the shape of the wings, a means of powering the plane, and control. Others had focused on the first two problems, but the Wrights knew from riding bicycles that control was the key. Watching birds in flight, Wilbur reasoned that control lay in the way birds twisted their wing tips. Translating the idea, he built a box kite and braced the wings in such a way that they could be twisted in opposite directions to make the kite bank and turn. This principle, which the Wright brothers called "wing warping," was a revolutionary break-through.

In 1900 they built a full-size, piloted version of a box kite and tested its control mechanisms at Kitty Hawk, North Carolina, where the winds are steady and sandy slopes made for soft landings. The prototype showed some promise. The following year, they went back to Kitty Hawk, as they would for the next three years.

"One of the core aspects of their ability was a great facility to literally visualize," says Peter Jakab, a historian with the National Air and Space Museum, "literally see in their mind's eye a mechanical device, move components of it around, or transfer mechanical devices from one technology to the airplane and make them work."

The brothers approached each problem methodically, keeping meticulous notes on the variations and results of each test. They would allow no guesswork, no "hunt and peck" approach to problem solving that was the standard in the world of 19th century inventions. After reviewing their work, the brothers realized the standard wing design data they relied upon was flawed and came up with an ingenious plan: They created a small wind tunnel and used miniature wings, built to scale, to determine the best wing shape for the greatest lift. The Wrights, for the first time, produced accurate aerodynamic tables.

With this new data, they built a glider with wings that produced enough lift; they also added a hinged tail rudder to increase the pilot's control. They made their third trip to Kitty Hawk in the summer of 1902. The glider succeeded--they had at last managed to glide through the air with control. Their next task was to turn their glider into an airplane.

With the help of a mechanic in the bike shop, the brothers built a small engine. Designing the propeller was harder, but here, too, Orville and Wilbur made another remarkable breakthrough. They realized the propeller worked like a wing, but instead of lifting the craft, it pulled the plane forward.

On December 17, 1903, on their fourth trip to Kitty Hawk, with a local fisherman present to photograph the event, Orville and Wilbur realized their dream, making four flights that historic day--the longest lasted fifty-seven seconds and traveled 852 feet.

The Wrights' work had inspired other plane developers--particularly the French. The brothers had applied for a patent in 1902, but were turned down. Fearful of being copied, they stubbornly refused to fly their machine--even when they were finally awarded a patent--until they received a contract for the purchase of a flying machine. Doubts about their ability had begun to surface: newspapers vilified the brothers as "bluffers"; meanwhile, other inventors were closing in. By early 1908, French aviator Henri Farman was flying his own machine. The craft lacked control, but it was flying. The French were convinced that they had conquered the air.

Finally, in 1908, the Wrights' claim reached President Theodore Roosevelt, and the brothers signed a deal for $25,000 to build and fly one of their machines for the US Army Signal Corps. A French deal soon followed. Later that year, when Wilbur finally made his demonstration flight around a racetrack in France before a small crowd of spectators, the French realized the Wright brothers had moved far beyond other aviators.

Once the Wrights had successfully marketed their invention, they returned to Ohio to manufacture airplanes. Orville managed the business while Wilbur took numerous patent infringers to court. In 1912, Wilbur became ill with typhoid on a business trip to Boston. He returned to the family home and died there three weeks later at the age of 45.

After Wilbur's death, Orville sold the business for $1 million and retired. He outlived Wilbur by more than 30 years, dying from a heart attack at the age of 76.