Breaking the sound barrier
Let’s have a look back on one of the most iconic aircraft which inspired many people to become a fighter pilot and pilot all over – the Bell X-1. Shortly after the Second World War, with the rise of the propulsion reactor, NACA, future NASA, assisted by the U.S. Air Force, was conducting a research program on high speed with a series of experimental aircrafts and especially catching up the sound barrier. It is approaching the sound barrier when the aircraft catches his own wave, which causes an increase in drag, a decrease in stability and difficulty to control the plane. The unit for expressing the speed is Mach number – after the Austrian physicist Ernst Mach, expressing a relationship between the speed of the machine and the speed of sound. The Bell X-1 is designed to confront the unknown in flight. Therefore engineers gave it the shape of a bullet, known to be supersonic. The device is dropped in flight from a B-29 and rocket engines are fired to accelerate. Several progressive tests will be performed until 14 October 1947. That day, the test pilot Charles “Chuck” Yeager goes officially for the first time beyond the sound barrier in level flight, flying the Bell X-1. We now know that other pilots have already reached such speeds in a dive but without knowing it due to the absence of a precise instrumentation and without sonic booms being understood at the time. Subsequently, a series of new X-1 was created to open up new areas of research and performance: speed (Mach 2.44 with the X-1A and X Mach 2.21 with E-1) and altitude (more than 20 000 m). Chuck Yeager joined in the U.S. Army Air Corps a few months before the engagement of the United States in World War II, in September 1941. Transferred in Britain in November 1943, he acquired the status of ace and ended the war with the rank of Captain with thirteen German aircrafts destroyed to his credit. He is one of the first pilots to have shot down a Me 262. After the war, Yeager remained in the newly created U.S. Air Force and became a pilot instructor and test pilot from July 1945. Transferred to the Muroc Field in California (now based Edwards), he is the first man to break the sound barrier on 14 October 1947 at 10h18, aboard the Bell X-1 prototype.