Fast jet

A supersonic aircraft is an aircraft able to fly faster than the speed of sound (Mach number 1). Supersonic aircraft were developed in the second half of the twentieth century and have been used almost entirely for research and military purposes. Only two, Concorde and the Tupolev Tu-144, ever entered service for civil use as airliners. Fighter jets are the most common example of supersonic aircraft.

The aerodynamics of supersonic flight is called compressible flow because of the compression (physics) associated with the shock waves or "sonic boom" created by any object travelling faster than sound.

Aircraft flying at speeds above Mach 5 are often referred to as hypersonic aircraft.

The first aircraft to fly supersonically in level flight was the American Bell X-1 experimental plane which was powered by a 6000-lb thrust rocket powered by liquid oxygen and ethyl alcohol.

The majority of supersonic aircraft have been military or experimental aircraft.

In the 1960s and '70s, many design studies for supersonic airliners were done and eventually two types entered service, the Anglo-French Concorde and the Russian Tupolev Tu-144. However political, environmental and economic obstacles and one fatal Concorde crash prevented them from being used to their full commercial potential and these aircraft are no longer flying.

Supersonic flight brings with it substantial technical challenges, as the aerodynamics of supersonic flight are dramatically different from those of subsonic flight (i.e., flight at speeds slower than that of sound). In particular, aerodynamic drag rises sharply as the aircraft passes the transonic regime, requiring much greater engine power and more streamlined airframes.

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Wikipedia