- Jet aircraft
A jet aircraft is an
aircraft propelled byjet engine s. Jet aircraft fly much faster thanpropeller -powered aircraft and at higher altitudes -- as high as 10,000 to 15,000 meters, about 33,000 to convert|49000|ft|m|-2. At these altitudes, jet engines achieve maximum efficiency over long distances. The engines in propeller powered aircraft achieve their maximum efficiency at much lower altitudes.Two engineers, Frank Whittle in the United Kingdom and Hans von Ohain in Germany, developed the concept independently during the late 1930s, although credit for the first turbojet is given to Whittle.
Although the concept had already been discussed as early as August 1928 by
Frank Whittle at Flying School, Wittering,Hans von Ohain wrote In February 1936 toErnst Heinkel , telling him of the design and its possibilities.It can be argued that A. A. Griffith, who published a paper in July 1926 on compressors and turbines, which he had been studying at the RAE, also deserves priority credit, perhaps more than either
Frank Whittle orHans von Ohain .Historical examples
The first turbine-equipped jetplane was designed on paper in late 1929 when
Frank Whittle of the BritishRoyal Air Force sent his concept to theAir Ministry to see if it would be of any interest to them. The first manufactured turbine jetplane was theHeinkel He 178 turbojet prototype of the German Air Force ("Luftwaffe "), piloted byErich Warsitz onAugust 27 ,1939 .The first flight of the Italian
Caproni Campini N.1 motorjet prototype was onAugust 27 ,1940 .Test pilot Major Mario De Bernardi of the Italian Royal Air Force ("Regia Aeronautica ") was at the controls.The British flew their
Gloster E.28/39 prototype onMay 15 ,1941 , powered bySir Frank Whittle 's turbojet, and piloted by Flt Lt PG Sayer. When theUnited States learned of the British work, it produced the Bell XP-59 with a version of the Whittle engine built byGeneral Electric , which flew onSeptember 12 ,1942 , piloted by Col L. Craigie.The first operational
jet fighter was theMesserschmitt Me 262 , piloted byFritz Wendel . It was the fastest conventional aircraft ofWorld War II - only the rocket-poweredMesserschmitt Me 163 Komet was faster. Mass production started in 1944, too late for a decisive impact on the outcome of the war. About the same time, the United Kingdom'sGloster Meteor was limited to defense of the UK against the V1 flying bomb and ground-attack operations over Europe in the last months of the war. TheImperial Japanese Navy also developed jet aircraft in 1945, including the Nakajima J9Y Kikka, partially inspired by German designs.On
November 8 ,1950 , during theKorean War ,United States Air Force Lt.Russell J. Brown , flying in an F-80, intercepted twoNorth Korea nMiG-15 s near theYalu River and shot them down in the first jet-to-jetdogfight in history.BOAC operated the first commercial jet service, fromLondon toJohannesburg , in 1952 with thede Havilland Comet jetliner .The fastest military jet plane was the
SR-71 Blackbird at Mach 3.2. The fastest commercial jet plane was theTupolev Tu-144 at Mach 2.35.Modern jets
Modern jets cruise at speeds of 0.75 to 0.85 Mach, or 75% to 85% of the
speed of sound (420 to 580 mph/ 680-900 km/h). The speed of sound predominantly depends on airtemperature (hardly at all onpressure ), so the Mach number for the speed of a jet also varies with atmospheric conditions.NASA and the USFederal Aviation Administration have been promotingVery Light Jet s: smallgeneral aviation aircraft seating 4 to 8 passengers.Other jets
Most people use the term 'jet aircraft' to denote gas turbine based airbreathing jet engines, but rockets and scramjets are both also propelled by jets.
The fastest airbreathing jet aircraft is the unmanned
X-43 scramjet at around Mach 9-10.The fastest manned (rocket) aircraft is the
X-15 at Mach 6.85.The
Space Shuttle , while far faster than the X-43 or X-15, is not regarded as a jet aircraft during ascent (although aerodynamic lift is used during some parts of this phase of operationFact|date=March 2008), nor during reentry and landing (as it is unpowered during this phase of operation).See also
*
Jumbo jet
*Jet airliner
*Commercial aviation
*Contrail External links
* [http://www.aircraft-info.net/aircraft/jet_aircraft/ Aircraft-Info.net - Jet Aircraft]
* [http://www.aerospaceweb.org/question/performance/q0023.shtml Aircraft Speed Records]
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