Brief
Chuck Yeager breaks sound barrier in Bell X-1 on Oct. 14, 1947
Yeager flew the Bell X-1 named “Glamorous Glennis” to Mach 1.07 at 43,000 feet, despite having broken two ribs the night before.
By Felo News Desk · Published
On Oct. 14, 1947, USAF Capt. Charles E. Yeager became the first person to fly faster than the speed of sound in level flight, reaching Mach 1.07 in the Bell X-1 rocket plane.
The X-1, a single‑pilot aircraft about 30 feet long with a 28‑foot wingspan, was dropped from a Boeing B‑29 bomber before its rocket engine ignited. Yeager, who had broken two ribs after falling off a horse the previous night, accelerated to roughly 821 mph (1,321 km/h) at 43,000 feet, surpassing the sound barrier’s 760 mph (1,223 km/h) threshold.
The Bell X‑1 originated as the XS‑1, a joint effort between the National Advisory Committee for Aeronautics (NACA) and the U.S. Army Forces, later the Air Force. Bell Aircraft won the contract in March 1945 and delivered the prototype in December that year. Prior to the historic flight, Yeager conducted three unpowered glide tests in August 1947 and a series of subsonic powered flights.
NASA notes that the flight was classified Top Secret for two hours and not publicly disclosed until December 1947; the U.S. Air Force formally confirmed the achievement in March 1948. The mission’s success demonstrated that the “sound barrier” could be broken and established the research‑aircraft model, where aircraft are built solely for experimental purposes without immediate military or commercial requirements.
Yeager named the X‑1 “Glamorous Glennis” after his wife. The aircraft’s rocket engine used liquid oxygen and ethyl‑alcohol‑water propellant. The flight laid the groundwork for subsequent X‑plane programs, including today’s NASA X‑59, which aims to test quieter supersonic booms for future commercial over‑land supersonic travel.
Key facts
- Chuck Yeager broke the sound barrier on Oct. 14, 1947 in the Bell X‑1. (space.com)
- The X‑1 reached Mach 1.07 (about 821 mph) at 43,000 feet. (space.com)
- Yeager had broken two ribs the night before the flight. (space.com)
- The flight was classified Top Secret for two hours and publicly disclosed in December 1947. (space.com)
- The Bell X‑1 was a joint NACA‑U.S. Army project, built by Bell Aircraft after a March 1945 contract. (space.com)
Sources
- [1] space.com — originally reported as “On this day in space! Oct. 14, 1947: Test pilot Chuck Yeager breaks the sound barrier in the Bell X-1, the first X-plane”
