Any speed over the speed of sound, which is approximately 343 m/s or 1,087 fps or 761 mph or 1,225 km/h at sea level, is said to be supersonic. Many modern fighter aircraft are supersonic. The Concorde was a supersonic passenger aircraft, but, since its final retirement flight on November 26 2003, there is no supersonic passenger aircraft in service. Most modern firearms munitions are supersonic, with rifle projectile often travelling at over Mach 2. Speeds greater than 5 times the speed of sound are sometimes referred to as hypersonic. Sound travels at different speeds depending on the density of the propagation medium. In air both temperature and pressure have an effect on the speed of sound, this is why supersonic speeds are given at sea level. In water at room temperature supersonic can be considered as any speed greater than 1,440 m/s or 4,724 fps.

Supersonic Travel - Breaking The Sound Barrier

In 1942 the United Kingdom's Ministry of Aviation began a top secret project with the Miles Aircraft Company to develope the Worlds first supersonic turbojet research aircraft. The project resulted in the development of the prototype Miles M.52 aircraft, which was designed to reach 1000 mph at 36,000 feet in 1 minute 30 seconds. The aircraft's design was revolutionary introducing many innovations which are still used on todays supersonic aircraft. The single most important development was the all-moving tailplane which allowed control to be maintained at supersonic speeds, this was the brainchild of Dennis Bancroft and his team at Miles Research. Unfortunately the project was cancelled by the Director of Scientific Research, Sir Ben Lockspeiser before any manned fights were conducted. Subsequently, on government orders, all design data and research regarding the Miles M.52 was sent to BELL aircraft in the USA. Later experimentation on the Miles M.52 design proved that the aircraft would indeed have broken the sound barrier, with an unmanned 3/10 scale replica of the M.52 achieving Mach 1.5 in October 1948.

Chuck Yeager was the first man to break the sound barrier in level flight on October 14 1947, flying the experimental Bell X-1 at Mach 1 at an altitude of 45,000 feet (13.7 km).

A team led by Richard Noble and driver Andy Green became the first to break the sound barrier in a land vehicle October 15 1997, almost exactly 50 years after Yeager's flight.

Hans Guido Mutke claimed to have broken the sound barrier before Yeager, on April 9 1945 in a Messerschmitt Me 262. However, this claim is disputed by most experts and lacks a scientific foundation.

See also

• Sound barrier
• Mach number