Propellers proved the hardest problem. Orville described it this way: with the machine moving forward, the air flying backward, the propeller turning sideways and nothing standing still, it seemed impossible to find a starting point. The Wrights realized that a propeller is a wing that turns on a spiral course, and they thought of their propellers as rotary wings. To test their theory they built a larger wind tunnel, two feet on each of four sides and eight feet long, which followed the smaller tunnel they had built in 1901 to test wing shapes. The Flyer's two propellers, turning in opposite directions at the back, together gave a thrust of 90 pounds, just enough to rise, fly and land.

Their propellers had an efficiency of 66 percent, compared with 40 to 50 percent for propellers designed in nineteenth-century Europe. The whole machine weighed about 600 pounds and had a wingspan of 40 feet. The Wrights built their own engine because they could not buy one light enough for their airplane, and it made about 12 horsepower. They built its crankcase of aluminum to save weight, and it had no throttle, so it could run only at full speed. Its first test, on February 12, 1903, ended with a seized engine and a shattered crankcase, but they rebuilt it completely, and it was running smoothly by May.

In 1901 the Wrights hired a mechanic named Charlie Taylor to look after their bicycle shop while they flew gliders. His first aeronautical job was building the wind tunnel whose data guided the improved 1902 glider. Later he made the engine's crankshaft, valves, intakes and connecting rods with shop tools primarily used for repairing bicycles. He recalled that the group made no engine drawings: one of them sketched a part on scratch paper, and he tacked the sketch over his bench.

The Army wanted an airplane that could be taken apart and moved by an army wagon, could carry two people, and could reach a speed of at least 40 miles per hour in still air. The Wrights had not flown in public for more than two years after 1905, to protect their invention before it was patented or sold. Their third airplane, built in 1905, is called the first practical airplane, and on October 5, 1905, Wilbur flew it for 39 minutes, about 24 miles. They later formed the Wright Company to build and sell airplanes and train pilots.

In 1908 and 1909 Wilbur gave demonstration flights in France. He was a cautious pilot who inspected his airplane carefully before each takeoff, and his 1908 flights near Le Mans amazed the crowds. The Wrights launched with a catapult: the airplane was tied by cables and pulleys to a weight in a tower, and when the weight fell it pulled the plane along a wooden rail fast enough to take off. In 1948 the 1903 Wright Flyer went from the London Science Museum to the Smithsonian Institution, and as of November 2026 it is on display in the National Air and Space Museum in Washington, D.C.

Words to know

• thrust: forward push
• efficiency: work done well
• crankshaft: engine spinner
• catapult: launching device