Supersonic Airplane
Supersonic airplanes are planes that can travel faster than the speed of sound. Sound travels at a speed of 742 miles per hour (1,194 kph) through air at 32° F (0° C). The first two commercial airliners designed to travel at supersonic speeds were the British-French Concorde and the Soviet Tupolev TU-144. They can fly between Europe and United States in about 3½ hours. Half the time that it takes a supersonic plane such as a Boeing 727. The Concorde was first flown in 1968. When a supersonic jet goes fasters than the speed of sound, it passes through the sound barrier. This causes a sonic boom—a loud atmospheric disturbance that sounds like thunder. It occurs when air is pushed aside by the plane and then rushes back when the plane has passed. Supersonic planes are highly streamlined in shape. They are made of strong, light metals that can withstand the high temperatures produced by flying at high speeds.