Today, most large commercial aircraft are powered by jet engines: hence the term "jet aircraft."
The jet engine is a far cry from the piston engine, which powered the Wright Flyer on December 17, 1903, whichheralded mankind’s historic first powered flight.
Aircraft jet engines use the principle of jet propulsion, that is, the propulsion of an object in one direction produced by ejecting a jet of fluid in the opposite direction.
The moving body is propelled in the opposite direction from the jet, based on Newton's third law of motion: "For every action (force) there is an equal and opposite reaction."
All jet propulsion engines are known as reaction engines.
The principle of jet propulsion dates back to the aeolipile, a device described by Hero of Alexandria in first-century Egypt.
The aeolipile consisted of a spherical vessel with oppositely bent or curved nozzles projecting outwards. When the vessel is filled with water and heated, steam is expelled out of the nozzles, which generates thrust thanks to the reaction principle based on Newton's third law of motion causing the vessel to rotate.
Rocket engines are reaction engines, producing thrust by ejecting gases rearward, in accordance with Newton's third law.
[caption id="attachment_1092724" align="alignnone" width="440"] An illustration of Hero's aeolipile -[/caption]
Most rocket engines use the combustion of reactive chemicals to supply the necessary propulsive force.
Rocket engines are commonly used by ballistic missiles to launch space vehicles. They carry their own oxidisers, unlike most combustion engines, and can be used in a vacuum to propel spacecraft and ballistic missiles.
The first working pulsejet was patented in 1906 by Russian engineer VV Karavodin, who completed a working model in 1907.
The French inventor Georges Marconnet patented his valveless pulsejet engine in 1908 and Ramon Casanova, in Ripoll, Spain, patented a pulsejet in Barcelona in 1917, having constructed one in 1913.
Robert Goddard invented a pulsejet engine in 1931 and demonstrated it on a jet-propelled bicycle.
Engineer Paul Schmidt pioneered a more efficient design based on modification of the intake valves, earning him government support from the German Air Ministry in 1933.
A pulsejet engine is a type of jet engine in which combustion occurs in pulses. A pulsejet engine can be made with few or no moving parts, and is capable of running statically without having air forced into its inlet. The best-known example is the Argus As 109-014 used to propel Nazi Germany's V-1 flying bomb during World War II.
Since the 1930s, aerospace engineers realised that the maximum performance of piston engines was limited, as propulsive efficiency declined as blade tips approached the speed of sound.
For engine performance to increase beyond the sound barrier, a radically improved piston-engine design was required, or a new type of propulsive engine powerplant would have to be developed. This led to the development of gas turbine engines.
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