longest flight lasting more than 5 minutes. In 1905, their best flight was 24.2 miles in 38 minutes and 3 seconds. On September 9,1908 Wilbur completed the world's first flight of more than one hour carrying a passenger. On September 17, 1908, the airplane crashed injuring Orville and his passenger Lieutenant Thomas E. Selfridge. Lieutenant Thomas E. Selfridge died hours later from a concussion. Orville continued demonstrations for the Signal Corps in July 1908. By the end of the month he met their requirements and the airplane was purchased on August 2, 1908. It became the first successful military airplane. It stayed in active service for two years. Today it is located at the Smithsonian Institution in Washington, D.C. Principle of Flight Lift Airplanes are able to fly because air moving over and under its surfaces, like its wings, travel at different velocities. It produces air pressure which is high below the wing and low above it. The high pressure pushes and the low pressure pulls. The lift of an airplane depends on the area, shape and tilt of the wing. And on the speed of the aircraft. The area of the wing is significant in causing the lift in an aircraft because, the more the wing is exposed to the air, the greater the lift. Different wing shapes produce a different area. The up or down tilt of the wing is called the angle of attack. As a wing is tilted upward, its angle of attack is increased which also increases the lift. Aircraft speed is also importa
             ...