# supersonic flight

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Related to supersonic flight: Hypersonic flight

## Supersonic flight

Relative motion of a solid body and a gas at a velocity greater than that of sound propagation under the same conditions. The general characteristics of supersonic flight can be understood by considering the laws of propagation of a disturbance or pressure impulse, in a compressible fluid.

If the fluid is at rest, the pressure impulse propagates uniformly with the velocity of sound in all directions, the effect always acting along an ever-increasing spherical surface. If, however, the source of the impulse is placed in a uniform stream, the impulse will be carried by the stream simultaneously with its propagation at sonic velocity relative to the stream. Hence the resulting propagation is faster in the direction of the stream and slower against the stream. If the velocity of the stream past the source of disturbance is supersonic, the effect of the impulse is restricted to a cone whose vertex is the source of the impulse and whose vertex angle decreases from 90° (corresponding to Mach number equal to 1) to smaller and smaller values as the Mach number of the stream increases (see illustration). If the source of the pressure impulse travels through the air at rest, the conditions are analogous.

Consider the supersonic motion of a wing moving into air at rest. Because signals cannot propagate ahead of the wing, the presence of the wing has no effect on the undisturbed air until the wing passes through it. Hence there must be an abrupt change in the properties of the undisturbed air as it begins to flow over the wing. This abrupt change takes place in a shock wave which is attached to the leading edge of the wing, provided that the leading edge is sharp and the flight Mach number is sufficiently large. As the air passes through the shock wave, its pressure, temperature, and density are markedly increased.

Further aft of the leading edge, the pressure of the air is decreased as the air expands over the surface of the wing. Hence the pressure acting on the front part of the wing is higher than the ambient pressure, and the pressure acting on the rear part of the wing is lower than the ambient pressure. The pressure difference between front and rear parts produces a drag, even in the absence of skin friction and flow separation. The wing produces a system of compression and expansion waves which move with it. This phenomenon is similar to that of a speedboat moving with a velocity greater than the velocity of the surface waves. Because of this analogy, supersonic drag is called wave drag. It is peculiar to supersonic flight, and it may represent the major portion of the total drag of a body. See Hypersonic flight, Subsonic flight, Transonic flight

McGraw-Hill Concise Encyclopedia of Engineering. © 2002 by The McGraw-Hill Companies, Inc.

## supersonic flight

A flight at an air speed at which the entire airflow over the aircraft is moving at a speed greater than that of sound.
References in periodicals archive ?
The FAA Reauthorisation Act also sets a bold timeline to address one of the most significant barriers to civil supersonic flight: landing-and-take-off noise.
In response to the FoI request, the MoD said supersonic flight is not routinely permitted over land in the UK and training is carried out over sea.
This aircraft is capable of supersonic flight and we do not have that kind of aircraft in our inventory.
As a result of concerns over the noise from SSTs, the FAA banned "commercial or civil aircraft from supersonic flight over the landmass or territorial waters of the United States if measurable overpressure would reach the surface" in 1973.
Peter Coen, head of the High Speed Project in NASA's Aeronautics Research Mission Directorate at the agency's Headquarters in Washington, said lessening sonic booms - shock waves caused by an aircraft flying faster than the speed of sound - is the most significant hurdle to reintroducing commercial supersonic flight.
In a statement to the newspaper, it said: "Without a doubt, Sir Richard and his children taking the first commercial flight into space will go down in history as one of the most memorable events on television." Last month Virgin Galactic's Space-ShipTwo made its third rocket-powered supersonic flight in the Mojave Desert, soaring to a record 71,000 feet.
The T-50, which will be the core of Russia's future fighter fleet, is a fifth-generation multi-role fighter aircraft featuring stealth and nano-technology, super-maneuverability, super cruise capability (supersonic flight without use of afterburner), and an advanced avionics suite including an X-band active phased-array radar, according to Sukhoi.
A spectacular, supersonic flight including music, couture fashion, dance and movement to celebrate the venue's centenary.
Concorde completed its first supersonic flight on October 1 in the same year.
14, 1947, supersonic flight in an airplane called the X-1--as does Yeager's own automobile license plate.
His designs, particularly "the area rule," allowed supersonic flight to evolve from a closely guarded military secret to commercial use.
Concorde completed its first supersonic flight on October 1, 1969 and the first commercial flights took place on January 21, 1976, when British Airways flew from London Heathrow to Bahrain and Air France from Paris to Rio.

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