HISTORYThe first examples of jet propulsion were Hero of Alexandria's Aeolipile (¥ c.70)Ñan elementary turbine driven by steam jetsÑand medieval Chinese rockets used as missiles against Kublai Khan. In the 19th century many jet engines were patented, but practical achievement awaited technological advances, notably heat-resisting metal alloys. No single person can be credited with the invention of jet propulsion. Among the pioneers are: for the rocket, Robert Goddard of the United States, Hermann Oberth and Wernher von Braun of Germany, and Sergei Korolev and Konstantin Tsiolkovsky of the Union of Soviet Socialist Republics (USSR); for the ramjet, RenŽ Leduc of France and Eugen SŠnger and Otto Pabst of Germany; and for the turbojet, Sir Frank Whittle of Great Britain, Hans von Ohain and Max Adolf MŸller of Germany, and Secondo Campini of Italy.The first jet-propelled airplane to fly was a rocket-propelled tail-first glider flown in Germany on June 11, 1928; in the tail-first configuration, stabilizing fins are situated ahead of the wing. Two German research airplanes were built by Ernst Heinkel in 1939; the He 176 was flown on rocket power in June (precise date not recorded), and the He 178 was flown on turbojet power on August 24 (a short hop) and August 27 (the first full flight). The first jet fighter to fly was the He 280 on Apr. 5, 1941, and the first to enter service was Britain's Gloster Meteor in July 1944.
However, the German Messerschmitt Me 262 was the first to engage an enemy and was built in larger numbers than any other World War II jet. The first jet transport was the British de Havilland Comet, flown on July 27, 1949, and in regular service from May 2, 1952.Today nearly all combat airplanes are jet propelled, as are virtually all large civil transports. The favored type of engine is the turbofan, a turbojet with an oversize low-pressure compressor whose extra airflow is discharged as a relatively cool and slow propulsive jet, which shows better propulsive efficiency, reduced fuel consumption, and dramatically lower noise level than an ordinary turbojet engine. Modern aircraft jet engines are among the most compact sources of power known, other than one-shot devices (devices used only once), such as artillery or bombs. They have found applications driving air-cushion vehicles, warships, merchant ships, electric utility plants, pipeline pumps, and many other tasks calling for high sustained power with high reliability.