First supersonic flight
Chuck Yeager, Bell XS-1 ("Glamorous Glennis")
first first
United States (Muroc Air Force Base)

The first supersonic flight was achieved by Captain (later Brigadier-General) Charles "Chuck" Elwood Yeager (USA), over Muroc Air Force Base in Calfornia, USA. On 14 October 1947, Yeager flew the Bell XS-1 (named Glamorous Glennis, after his wife) to Mach 1.06, which works out to an airspeed of around 700 mph (1,126 km/h) at an altitude of 43,000 ft (13,100 m).

The Bell XS-1 (later redesignated the X-1), was an experimental aircraft built in 1945 for a joint NACA–US Air Force program to study supersonic flight. Its streamlined fuselage was based on the shape of a .50 calibre bullet, as this was a shape known to be stable in supersonic flight. It had short, straight wings and an all-moving tail (in which the entire rear stabilizer moves as a control surface). It was powered by an Reaction Motors XLR-11 rocket engine, which burned liquid oxygen and ethyl alcohol to create 6,000 pounds-force (27,000 N) of thrust (significantly more than was possible with the jet engines of the time). It did not have the fuel or the power to reach these speeds from the ground, and so had to be dropped at high altitude from a B-29 Superfortress "mothership".

The XS-1 made its first flight on 19 Jan 1946. It was released from its mothership over Pinecastle Field, near Orlando, Florida, with Bell test pilot Jack Woolams at the controls. After these initial shakedown flights, it was shipped out to Muroc Air Force Base in April 1946.

Over the next 20 months, the XS-1 was gradually pushed further, making powered flights at gradually increasing speeds under the control of pilot Chalmers "Slick" Goodlin – an ex-military test pilot working for the Bell Aircraft Corporation. At Muroc the US Air Force handled flight operations, while technicians from the NACA (the predecessor to NASA) handled the telemetry and scientific analysis.

Yeager was brought in by the US Air Force to fly the aircraft after a dispute between Goodlin and the US Air Force officials running the project. Yeager made his first flight on 6 August 1947. The record setting flight was his ninth.

The details of the flight were leaked to Aviation Week in December 1947, but the record-setting flight wasn't publicly confirmed by the US Air Force until Jun 1948. Yeager continued to fly the XS-1 until May 1950, when it was retired in favour of faster designs. The XS-1 is now housed at the Smithsonian Air and Space Museum in Washington D.C.