Editing Jet engine (section)

== History ==
{{Main article|History of the jet engine}}
{{See also|Timeline of jet power}}
The  principle of the jet engine is not new; however, the technical advances necessary to make the idea work did not come to fruition until the 20th century.
A rudimentary demonstration of jet power dates back to the [[aeolipile]], a device described by [[Hero of Alexandria]] in [[Roman Egypt|1st-century Egypt]]. This device directed [[steam power]] through two nozzles to cause a sphere to spin rapidly on its axis.  It was seen as a curiosity. Meanwhile, practical applications of the [[turbine]] can be seen in the [[water wheel]] and the [[windmill]]. 

Historians have further traced the theoretical origin of the principles of jet engines to traditional Chinese firework and rocket propulsion systems. Such devices' use for flight is documented in the story of Ottoman soldier [[Lagâri Hasan Çelebi]], who reportedly achieved flight using a cone-shaped rocket in 1633.<ref name="Hendrickson">{{cite book |last1=Hendrickson |first1=Kenneth E. |title=The Encyclopedia of the Industrial Revolution in World History |date=2014 |publisher=Rowman & Littlefield |isbn=9780810888883 |page=488 |url=https://books.google.com/books?id=EdwsCgAAQBAJ&pg=PA488}}</ref>

The earliest attempts at airbreathing jet engines were hybrid designs in which an external power source first compressed air, which was then mixed with fuel and burned for jet thrust.  The Italian [[Caproni Campini N.1]], and the Japanese [[Tsu-11]] engine intended to power [[Ohka]] [[kamikaze]] planes towards the end of [[World War II]] were unsuccessful.

Even before the start of World War II, engineers were beginning to realize that engines driving propellers were approaching limits due to issues related to propeller efficiency,<ref>[http://selair.selkirk.bc.ca/aerodynamics1/Performance/Page8.html propeller efficiency] {{webarchive |url=https://web.archive.org/web/20080525093007/http://selair.selkirk.bc.ca/aerodynamics1/Performance/Page8.html |date=May 25, 2008 }}</ref> which declined as blade tips approached the [[speed of sound]].  If aircraft performance were to increase beyond such a barrier, a different propulsion mechanism was necessary. This was the motivation behind the development of the gas turbine engine, the most common form of jet engine.

The key to a practical jet engine was the [[gas turbine]], extracting power from the engine itself to drive the [[gas compressor|compressor]]. The gas turbine was not a new idea: the patent for a stationary turbine was granted to [[John Barber (engineer)|John Barber]] in England in 1791. The first gas turbine to successfully run self-sustaining was built in 1903 by Norwegian engineer [[Ægidius Elling]].<ref>{{cite book |date=14 June 2004|doi=10.1115/GT2004-53211 |isbn=978-0-7918-4167-9 |chapter=Centenary of the First Gas Turbine to Give Net Power Output: A Tribute to Ægidius Elling |title=Volume 2: Turbo Expo 2004 |pages=83–88 |last1=Bakken |first1=Lars E. |last2=Jordal |first2=Kristin |last3=Syverud |first3=Elisabet |last4=Veer |first4=Timot }}</ref> Such engines did not reach manufacture due to issues of safety, reliability, weight and, especially, sustained operation.

The first patent for using a gas turbine to power an aircraft was filed in 1921 by [[Maxime Guillaume]].<ref>{{Cite web|url=https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=FR&NR=534801&KC=&FT=E|title=Propulseur par réaction sur l'air |website=Espacenet – patent search}}</ref><ref>{{Cite web|url=https://www.sciencefocus.com/science/who-really-invented-the-jet-engine/|title=Who really invented the jet engine?|website=BBC Science Focus Magazine|language=en|access-date=2019-10-18}}</ref> His engine was an axial-flow turbojet, but was never constructed, as it would have required considerable advances over the state of the art in compressors. [[Alan Arnold Griffith]] published ''An Aerodynamic Theory of Turbine Design'' in 1926 leading to experimental work at the [[Royal Aircraft Establishment|RAE]].
[[File:CS-1 kisérleti repülőgép gázturbina.jpg|thumb|[[Jendrassik Cs-1|CS-1]] Turboprop engine of [[György Jendrassik]] in 1940]]
[[File:Whittle Jet Engine W2-700.JPG|thumb|right|The [[Whittle W.2]]/700 engine flew in the [[Gloster E.28/39]], the first British aircraft to fly with a turbojet engine, and the [[Gloster Meteor]]]]
In 1928, [[RAF College Cranwell]] cadet [[Frank Whittle]] formally submitted his ideas for a turbojet to his superiors.<ref>{{cite web|url=https://www.pbs.org/kcet/chasingthesun/innovators/fwhittle.html
 |title=Chasing the Sun – Frank Whittle
 |publisher=PBS |access-date=2010-03-26}}</ref> In October 1929, he developed his ideas further.<ref>{{cite web|url=https://www.bbc.co.uk/history/historic_figures/whittle_frank.shtml
 |title=History – Frank Whittle (1907–1996)
 |publisher=BBC |access-date=2010-03-26}}</ref> On 16 January 1930, in England, Whittle submitted his first patent (granted in 1932).<ref>{{Cite web |url=https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=GB&NR=347206&KC=&FT=E |title=Improvements relating to the propulsion of aircraft and other vehicles |website=Espacenet – patent search |access-date=2020-05-30 |archive-date=2022-06-21 |archive-url=https://web.archive.org/web/20220621183123/https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=GB&NR=347206&KC=&FT=E |url-status=dead }}</ref> The patent showed a two-stage [[axial compressor]] feeding a single-sided [[centrifugal compressor]]. Practical axial compressors were made possible by ideas from [[Alan Arnold Griffith|A.A.Griffith]] in a seminal paper in 1926 ("An Aerodynamic Theory of Turbine Design"). Whittle would later concentrate on the simpler centrifugal compressor only. Whittle was unable to interest the government in his invention, and development continued at a slow pace.

[[File:Ohain USAF He 178 page61.jpg|thumb|left|[[Heinkel He 178]], the world's first aircraft to fly purely on turbojet power]]
In Spain, pilot and engineer [[Virgilio Leret Ruiz]] was granted a patent for a jet engine design in March 1935. [[Second Spanish Republic|Republican]] president [[Manuel Azaña]] arranged for initial construction at the [[Hispano-Suiza]] aircraft factory in Madrid in 1936, but Leret was executed months later by [[Francoist Spain|Francoist]] [[Spanish protectorate in Morocco|Moroccan]] troops after unsuccessfully defending his seaplane base on the first days of the [[Spanish Civil War]]. His plans, hidden from Francoists, were secretly given to the British embassy in Madrid a few years later by his wife, [[Carlota O'Neill]], upon her release from prison.<ref>{{cite web|url=https://english.elpais.com/elpais/2014/05/27/inenglish/1401200493_016805.html|title=Spain's forgotten jet-engine genius|website=EL PAÍS English |first1=Natalia |last1=Junquera |date=29 May 2014|access-date=2 September 2021}}</ref><ref>{{cite web|url=https://www.aerotendencias.com/cultura-aviacion/23225-el-museo-del-aire-acoge-una-replica-del-motor-a-reaccion-que-diseno-virgilio-leret/|title=El Museo del Aire acoge una réplica del motor a reacción que diseñó Virgilio Leret|website=Aerotendencias |date=9 June 2014|access-date=2 September 2021}}</ref> 

In 1935, [[Hans von Ohain]] started work on a similar design to Whittle's in Germany, both compressor and turbine being radial, on opposite sides of the same disc, initially unaware of Whittle's work.<ref>[https://archive.today/20120709114709/http://inventors.about.com/library/inventors/bljetengine.htm The History of the Jet Engine – Sir Frank Whittle – Hans Von Ohain<!-- Bot generated title -->] Ohain said that he had not read Whittle's patent and Whittle believed him. ([http://www.solarnavigator.net/inventors/frank_whittle.htm Frank Whittle 1907–1996]).</ref> Von Ohain's first device was strictly experimental and could run only under external power, but he was able to demonstrate the basic concept. Ohain was then introduced to [[Ernst Heinkel]], one of the larger aircraft industrialists of the day, who immediately saw the promise of the design. Heinkel had recently purchased the Hirth engine company, and Ohain and his master machinist Max Hahn were set up there as a new division of the Hirth company. They had their first [[Heinkel HeS 1|HeS 1]] centrifugal engine running by September 1937. Unlike Whittle's design, Ohain used [[hydrogen]] as fuel, supplied under external pressure. Their subsequent designs culminated in the [[gasoline]]-fuelled [[Heinkel HeS 3|HeS 3]] of {{convert|5|kN|lbf|abbr=on}}, which was fitted to Heinkel's simple and compact [[Heinkel He 178|He 178]] airframe and flown by [[Erich Warsitz]] in the early morning of August 27, 1939, from [[Rostock]]-Marienehe [[aerodrome]], an impressively short time for development. The He 178 was the world's first jet plane.<ref>Warsitz, Lutz: [http://www.pen-and-sword.co.uk/?product_id=1762 ''The First Jet Pilot – The Story of German Test Pilot Erich Warsitz'' (p. 125), Pen and Sword Books Ltd., England, 2009] {{Webarchive|url=https://web.archive.org/web/20131202223101/http://www.pen-and-sword.co.uk/?product_id=1762 |date=2013-12-02 }}</ref> Heinkel applied for a US patent covering the Aircraft Power Plant by Hans Joachim Pabst von Ohain on May 31, 1939; patent number US2256198, with M Hahn referenced as inventor. Von Ohain's design, an axial-flow engine, as opposed to Whittle's centrifugal flow engine, was eventually adopted by most manufacturers by the 1950s.<ref>Experimental & Prototype US Air Force Jet Fighters, Jenkins & Landis, 2008</ref><ref>{{cite news | url=https://www.nytimes.com/1996/08/10/world/frank-whittle-89-dies-his-jet-engine-propelled-progress.html | title=Frank Whittle, 89, Dies; His Jet Engine Propelled Progress | work=The New York Times | date=10 August 1996 | last1=Foderaro | first1=Lisa W. }}</ref>

[[File:Junkers Jumo 004.jpg|thumb|A cutaway of the Junkers Jumo 004 engine]]
[[Austria]]n [[Anselm Franz]] of [[Junkers (Aircraft)|Junkers]]' engine division (''Junkers Motoren'' or "Jumo") introduced the [[axial-flow compressor]] in their jet engine. Jumo was assigned the next engine number in the [[Reich Air Ministry|RLM]] 109-0xx numbering sequence for gas turbine aircraft powerplants, "004", and the result was the [[Junkers Jumo 004|Jumo 004]] engine. After many lesser technical difficulties were solved, mass production of this engine started in 1944 as a powerplant for the world's first jet-[[fighter aircraft]], the [[Messerschmitt Me 262]] (and later the world's first jet-[[bomber]] aircraft, the [[Arado Ar 234]]). A variety of reasons conspired to delay the engine's availability, causing the fighter to arrive too late to improve Germany's position in [[World War II]], however this was the first jet engine to be used in service.

[[File:Gloster Meteor III ExCC.jpg|thumb|left|Gloster Meteor F.3s. The [[Gloster Meteor]] was the first British jet fighter and the [[Allies of World War II|Allies']] only jet aircraft to achieve combat operations during World War II.]]
Meanwhile, in Britain the [[Gloster E28/39]] had its maiden flight on 15 May 1941 and the [[Gloster Meteor]] finally entered service with the [[RAF]] in July 1944. These were powered by turbojet engines from Power Jets Ltd., set up by Frank Whittle. The first two operational turbojet aircraft, the Messerschmitt Me 262 and then the Gloster Meteor entered service within three months of each other in 1944; the Me 262 in April and the Gloster Meteor in July. The Meteor only saw around 15 aircraft enter World War II action, while up to 1400 Me 262 were produced, with 300 entering combat, delivering the first ground attacks and air combat victories of jet planes.<ref>{{Cite book|url= https://books.google.com/books?id=449Ob41RgZMC&pg=PT103|title=The Me 262 Stormbird: From the Pilots Who Flew, Fought, and Survived It|last1=Heaton |first1= Colin D.|last2=Lewis|first2= Anne-Marien|last3=Tillman|first3= Barrett |date= 15 May 2012|publisher= Voyageur Press |isbn=978-1-61058434-0}}</ref><ref>{{cite book |last1=Listemann |first1=Phil H. |title=The Gloster Meteor F.I & F.III |date=6 September 2016 |publisher=Philedition |isbn=978-2-918590-95-8 |page=5 |url=https://books.google.com/books?id=DgakDAAAQBAJ&pg=PA5 |language=en}}</ref><ref>{{cite web | url=https://www.smithsonianmag.com/smithsonian-institution/day-germanys-first-jet-fighter-soared-history-180978152/ | title=The Day Germany's First Jet Fighter Soared into History }}</ref>

Following the end of the war the German jet aircraft and jet engines were extensively studied by the victorious allies and contributed to work on early [[Soviet Union|Soviet]] and US jet fighters. The legacy of the axial-flow engine is seen in the fact that practically all jet engines on [[fixed-wing aircraft]] have had some inspiration from this design.

By the 1950s, the jet engine was almost universal in combat aircraft, with the exception of cargo, liaison and other specialty types. By this point, some of the British designs were already cleared for civilian use, and had appeared on early models like the [[de Havilland Comet]] and [[Avro Canada Jetliner]]. By the 1960s, all large civilian aircraft were also jet powered, leaving the [[Reciprocating engine|piston engine]] in low-cost niche roles such as [[cargo]] flights.

The efficiency of turbojet engines was still rather worse than piston engines, but by the 1970s, with the advent of [[High-bypass turbofan engine|high-bypass turbofan jet engines]] (an innovation not foreseen by the early commentators such as [[Edgar Buckingham]], at high speeds and high altitudes that seemed absurd to them), fuel efficiency was about the same as the best piston and propeller engines.<ref name=hist8>{{cite web |url=http://www.hq.nasa.gov/pao/History/SP-468/ch10-3.htm |title=ch. 10-3 |publisher=Hq.nasa.gov |access-date=2010-03-26 |archive-date=2010-09-14 |archive-url=https://web.archive.org/web/20100914184628/http://www.hq.nasa.gov/pao/History/SP-468/ch10-3.htm |url-status=dead }}</ref>