A ramjet is a form of airbreathing jet engine that requires forward motion of the engine to provide air for combustion. Ramjets work most efficiently at supersonic speeds around Mach 3 and can operate up to Mach 6.
An AQM-60 Kingfisher, the first production ramjet to enter service with the US military
Upper engine is a ramjet on the Bloodhound missile
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Bristol Thor ramjet modified for display purposes. Two Thor engines were used on the Bristol Bloodhound missile
An airbreathing jet engine is a jet engine in which the exhaust gas which supplies jet propulsion is atmospheric air, which is taken in, compressed, heated, and expanded back to atmospheric pressure through a propelling nozzle. Compression may be provided by a gas turbine, as in the original turbojet and newer turbofan, or arise solely from the ram pressure of the vehicle's velocity, as with the ramjet and pulsejet.
A propfan engine