Bell Helicopters
Bell X-1A Glamorous Glennis

The Bell X-1 (Bell Model 44) is a rocket engine–powered aircraft, designated originally as the XS-1, and was a joint National Advisory Committee for Aeronautics–U.S. Army Air Forces–U.S. Air Force supersonic research project built by Bell Aircraft. Conceived during 1944 and designed and built in 1945, it achieved a speed of nearly 1,000 miles per hour (1,600 km/h; 870 kn) in 1948. A derivative of this same design, the Bell X-1A, having greater fuel capacity and hence longer rocket burning time, exceeded 1,600 miles per hour (2,600 km/h; 1,400 kn) in 1954. The X-1 aircraft #46-062, nicknamed Glamorous Glennis and flown by Chuck Yeager, was the first piloted airplane to exceed the speed of sound in level flight and was the first of the X-planes, a series of American experimental rocket planes (and non-rocket planes) designed for testing new technologies.

In 1942, the United Kingdom's Ministry of Aviation began a top secret project with Miles Aircraft to develop the world's first aircraft capable of breaking the sound barrier. The project resulted in the design of the turbojet-powered Miles M.52, with a maximum speed of 1,000 miles per hour (870 kn; 1,600 km/h) (over twice the existing airspeed record) in level flight, and able to climb to an altitude of 36,000 ft (11 km) in 1 min and 30 sec.

Mach 1 flight

The first manned supersonic flight occurred on 14 October 1947, over the Mojave Desert in California, less than a month after the U.S. Air Force had been created as a separate service. Captain Charles "Chuck" Yeager piloted USAF aircraft #46-062, nicknamed Glamorous Glennis for his wife. The airplane was drop launched from the bomb bay of a B-29 and reached Mach 1.06 (700 miles per hour (1,100 km/h; 610 kn)). Following burnout of the engine, the plane glided to a landing on the dry lake bed.^{: 129–130} This was XS-1 flight number 50.