Bell X-1 supersonic aircraft, illustration. The Bell X-1 was flown by Charles 'Chuck' Yeager on 14th October 1947 and was the first aircraft to break the speed of sound. It was carried into the air under a converted B-29 bomber, and released at 6800 metres altitude over Muroc, California, USA. The X-1 was powered by a four-chamber XLR-11 rocket engine that generated 26.5 kilonewtons of thrust. This pushed the aircraft to a speed of 1078 kilometres per hour at an altitude of 12,800 metres - equivalent to 1.015 times the speed of sound. Yeager unofficially named the aircraft 'Glamorous Glennis' after his wife. It is now displayed in a museum in Washington DC, USA.