Powered, sustained flight
With the major aerodynamic and control problems behind them, the brothers pressed forward with the design and construction of their first powered machine. They designed and built a four-cylinder internal-combustion engine with the assistance of Charles Taylor, a machinist whom they employed in the bicycle shop. Recognizing that propeller blades could be understood as rotary wings, the Wrights were able to design twin pusher propellers on the basis of their wind-tunnel data.
The brothers returned to their camp near the Kill Devil Hills in September 1903. They spent the next seven weeks assembling, testing, and repairing their powered machine and conducting new flight tests with the 1902 glider. Wilbur made the first attempt at powered flight on December 14, but he stalled the aircraft on take-off and damaged the forward section of the machine. Three days were spent making repairs and waiting for the return of good weather. Then, at about 10:35 on the morning of December 17, 1903, Orville made the first successful flight, covering 120 feet (36 metres) through the air in 12 seconds. Wilbur flew 175 feet (53 metres) in 12 seconds on his first attempt, followed by Orville’s second effort of 200 feet (60 metres) in 15 seconds. During the fourth and final flight of the day, Wilbur flew 852 feet (259 metres) over the sand in 59 seconds. The four flights were witnessed by five local citizens. For the first time in history, a heavier-than-air machine had demonstrated powered and sustained flight under the complete control of the pilot. (See Wright flyer of 1903.)
Determined to move from the marginal success of 1903 to a practical airplane, the Wrights in 1904 and 1905 built and flew two more aircraft from Huffman Prairie, a pasture near Dayton. They continued to improve the design of their machine during these years, gaining skill and confidence in the air. By October 1905 the brothers could remain aloft for up to 39 minutes at a time, performing circles and other maneuvers. Then, no longer able to hide the extent of their success from the press, and concerned that the essential features of their machine would be understood and copied by knowledgeable observers, the Wrights decided to cease flying and remain on the ground until their invention was protected by patents and they had negotiated a contract for its sale. (Their most successful machine to that date is described in the entry Wright flyer of 1905.)
Making the invention public
The claim of the Wright brothers to have flown was widely doubted during the years 1906–07. During that period a handful of European and American pioneers struggled into the air in machines designed on the basis of an incomplete understanding of Wright technology. Meanwhile the brothers, confident that they retained a commanding lead over their rivals, continued to negotiate with financiers and government purchasing agents on two continents.
In February 1908 the Wrights signed a contract for the sale of an airplane to the U.S. Army. They would receive $25,000 for delivering a machine capable of flying for at least one hour with a pilot and passenger at an average speed of 40 miles (65 km) per hour. The following month, they signed a second agreement with a group of French investors interested in building and selling Wright machines under license.
With the new aircraft that they would fly in America and France ready for assembly, the Wright brothers returned to the Kill Devil Hills in May 1908, where they made 22 flights with their old 1905 machine, modified with upright seating and hand controls. On May 14 Wilbur carried aloft the first airplane passenger—mechanic Charles Furnas.
Wilbur then sailed to France, where he captured the European imagination with his first public flight; this took place over the Hunaudières Race Course near Le Mans on August 8, 1908. During the months that followed, the elite of the continent traveled to watch Wilbur fly at Le Mans and Pau in France and at Centocelle near Rome.
Orville began the U.S. Army trials at Fort Myer, Virginia, with a flight on September 3, 1908. Fourteen days later a split propeller precipitated a crash that killed his passenger, Lieut. Thomas E. Selfridge, and badly injured the pilot. During the course of his recovery, Orville and his sister Katharine visited Wilbur in Europe. Together, the brothers returned to Fort Myer to complete the Army trials in 1909. Having exceeded the required speed of 40 miles (65 km) per hour, the Wrights earned a bonus of $5,000 beyond the $25,000 contract price. (For a more detailed account of these trials, see Wright military flyer of 1909.)
Following the successful Fort Myer trials, Orville traveled to Germany, where he flew at Berlin and Potsdam. Wilbur made several important flights as part of New York City’s Hudson-Fulton Celebration, then went to College Park, Maryland, where he taught the first three U.S. Army officers to fly.