The ramjet is the simplest type of jet engine and has no moving parts. It was invented by René Lorin in 1912.
The ramjet is increasingly becoming the most promising propulsion system for long duration flights in the atmosphere at speeds in excess of Mach 3. Various applications, both civil (reusable space launchers) and military (missiles etc.) are envisaged. The supersonic combustion scramjet or ramjet, is the only aerobic engine able to propel hypersonic vehicles faster than around Mach 7.
The ramjet is composed of a tube open at both ends into which fuel is injected, which mixes with air and is ignited by an ignition system. The result of this combustion is that large amounts of hot gas are produced which accelerate and decompress in the reactor end nozzle, giving substantial thrust.