Just how fast is the speed of sound?
The speed of sound is the distance travelled per unit time by a sound wave propagating through an elastic medium. The SI unit of the speed of sound is the metre per second (m/s). In dry air at 20 °C, the speed of sound is 343.2 metres per second (1,126 ft/s). This is 1,236 kilometres per hour (768 mph; 667 kn), or a kilometre in 2.914 s or a mile in 4.689 s.
On October 14, 1947, U.S. Air Force Captain Chuck Yeager becomes the first person to fly faster than the speed of sound.
Who was Chuck Yeager?
- Born in Myra, West Virginia, in 1923
- Combat fighter during World War II and flew 64 missions over Europe.
- Shot down 13 German planes and was himself shot down over France, but he escaped capture with the assistance of the French Underground.
- After the war, he was among several volunteers chosen to test-fly the experimental X-1 rocket plane, built by the Bell Aircraft Company to explore the possibility of supersonic flight.
It was believed by many aviators that attempting to fly faster than the speed of sound would tear up the aircraft. Chuck Yeager put these theories of transonic drag to rest on October 14, 1947. With his X-1, he flew over Rogers Dry Lake in Southern California and was lifted to an altitude of 25,000 feet by a B-29 aircraft and then released through the bomb bay, rocketing to 40,000 feet and exceeding 662 miles per hour (the sound barrier at that altitude). The rocket plane, nicknamed “Glamorous Glennis,” was designed with thin, unswept wings and a streamlined fuselage modeled after a .50-caliber bullet.
Here is Chuck Yeager doing it again in 2012