Editing Aircraft engine

{{Short description|Engine designed for use in powered aircraft}}
{{Redirect|Aero-engine|the use of aircraft engines in cars|Aero-engined car}}
[[File:YorkMerlin.JPG|thumb|300px|A [[Rolls-Royce Merlin]] installed in a preserved [[Avro York]] ]]
{{Seriesbox aircraft propulsion}}

An '''aircraft engine''', often referred to as an '''aero engine''', is the power component of an [[aircraft]] [[Air propulsion|propulsion system]]. Aircraft using power components are referred to as '''powered flight'''.<ref>{{cite book |title=A Dictionary of Aviation |first=David W. |last=Wragg |isbn=9780850451634 |edition=first |publisher=Osprey |year=1973 |page=215}}</ref> Most aircraft engines are either [[Reciprocating engine|piston engines]] or [[gas turbine]]s, although a few have been [[Rocket-powered aircraft|rocket powered]] and in recent years many small [[UAV]]s have used [[electric motor]]s.

==Manufacturing industry==
{{see also|List of aircraft engines}}The largest manufacturer of [[turboprop]] engines for [[general aviation]] is Pratt & Whitney.<ref name="turbopropmanufacturer">{{cite news|title=GE Pushes Into Turboprop Engines, Taking on Pratt|url=https://www.wsj.com/articles/ge-pushes-into-turboprop-engines-taking-on-pratt-1447700601|agency=Wall Street Journal|date=November 16, 2015}}</ref> General Electric announced in 2015 entrance into the market.<ref name="turbopropmanufacturer"/>

==Development history==
[[File:Wright Vertical Four-Cylinder Engine.jpg|thumb|right|Wright vertical 4-cylinder engine]]{{Incomplete list|date=March 2025}}{{See also|Timeline of jet power}}

* 1903: [[Manly-Balzer engine]] sets standards for later [[radial engine]]s.<ref name="e">{{cite book|title= Encyclopedia of the History of Technology |year=1990|publisher=Routledge|location=London|isbn= 978-0-203-19211-5|pages=[https://archive.org/details/encyclopaediaofh00mcne/page/315 315]–21|url= https://archive.org/details/encyclopaediaofh00mcne|url-access= registration | editor= Ian McNeil}}</ref>
* 1910: [[Coandă-1910]], an unsuccessful [[ducted fan]] aircraft exhibited at Paris Aero Salon, powered by a piston engine. The aircraft never flew, but a patent was filed for routing exhaust gases into the duct to augment thrust.<ref>{{cite book |last=Gibbs-Smith |first=Charles Harvard |title=Aviation: an historical survey from its origins to the end of World War II |url=https://books.google.com/books?id=hxEOAQAAIAAJ |year=1970 |location=London |publisher=[[Her Majesty's Stationery Office]]|isbn=9780112900139 }}</ref><ref>{{cite book |last=Gibbs-Smith |first=Charles Harvard |author-link=Charles Harvard Gibbs-Smith | title=The Aeroplane: An Historical Survey of Its Origins and Development |url=https://books.google.com/books?id=mzcZAAAAIAAJ |year=1960 |location=London |publisher=[[Her Majesty's Stationery Office]]}}</ref><ref>{{Cite journal |last=Winter |first=Frank H. |title=Ducted Fan or the World's First Jet Plane? The Coanda claim re-examined |journal=The Aeronautical Journal |publisher=Royal Aeronautical Society |volume=84 |date=December 1980|issue=839 |pages=408–416 |doi=10.1017/S0001924000031407 |url=https://books.google.com/books?id=XkBWAAAAMAAJ|url-access=subscription }}</ref><ref>{{Cite book |title=Henri Coandă and his technical work during 1906–1918 |last1=Antoniu |first1=Dan |last2=Cicoș |first2=George |last3=Buiu |first3=Ioan-Vasile |last4=Bartoc |first4=Alexandru |last5=Șutic |first5=Robert |language=ro |publisher=Editura Anima |location=Bucharest |isbn=978-973-7729-61-3|year=2010 }}</ref>
* 1914: [[Auguste Rateau]] suggests using exhaust-powered compressor – a [[turbocharger]] – to improve high-altitude performance;<ref name=e/> not accepted after the tests<ref>{{cite book|last=Guttman|first=Jon|title=SPAD XIII vs. Fokker D VII: Western Front 1918|year=2009|publisher=Osprey|location=Oxford|isbn= 978-1-84603-432-9|pages=24–25|url= https://books.google.com/books?id=8TBE5nGmxbEC&pg=PA25|edition=1st}}</ref>
* 1918: [[Sanford Alexander Moss]] picks up Rateau's idea and creates the first successful turbocharger<ref name=e/><ref name=p>{{cite journal |last=Powell|first=Hickman|title=He Harnessed a Tornado...|journal=Popular Science|date=Jun 1941|url= https://books.google.com/books?id=UycDAAAAMBAJ&pg=PA66}}</ref>
* 1926: [[Armstrong Siddeley Jaguar]] IV (S), the first series-produced supercharged engine for aircraft use.<ref name=a>{{cite book|last=Anderson|first=John D |title=The airplane: A history of its technology.|year=2002|publisher=American Institute of Aeronautics and Astronautics|location=Reston, VA, USA |isbn= 978-1-56347-525-2|pages= 252–53|url= https://books.google.com/books?id=FrvrkXYDCL8C&pg=PA253}}</ref><ref group="nb">The world's first series-produced cars with superchargers came earlier than aircraft. These were [[Mercedes (car)|Mercedes]] 6/25/40&nbsp;hp and Mercedes 10/40/65&nbsp;hp, both models introduced in 1921 and used Roots superchargers. {{cite book|title= The new encyclopedia of motorcars 1885 to the present|year= 1982|publisher= Dutton|location= New York|isbn= 978-0-525-93254-3|pages= [https://archive.org/details/newencyclopediao0000unse_v2r4/page/415 415]|edition= 3rd|editor= G.N. Georgano|editor-link= G.N. Georgano|url= https://archive.org/details/newencyclopediao0000unse_v2r4/page/415}}</ref>
* 2020: [[Pipistrel E-811]] is the first electric aircraft engine to be awarded a type certificate by [[EASA]]. It powers the [[Pipistrel Velis Electro]], the first fully electric EASA type-certified aeroplane.<ref name="E811_Flyer" />

==Shaft engines==
===Reciprocating (piston) engines===
{{main|reciprocating engine}}

====In-line engine====
''For other configurations of aviation inline engine, such as [[X engine|X-engines]], [[U engine|U-engines]], [[H engine|H-engines]], etc., see [[Inline engine (aeronautics)]].''{{main|Straight engine}}{{Empty section|date=March 2025}}[[File:Ranger L-440.jpg|thumb|Ranger L-440 air-cooled, six-cylinder, inverted, in-line engine used in [[Fairchild PT-19]]]]

====V-type engine====
[[File:Rolls-Royce Merlin.jpg|thumb|left|A Rolls-Royce Merlin V-12 Engine]]
{{main|V engine}}{{Empty section|date=March 2025}}

====Horizontally opposed engine====
{{main|Flat engine}}
[[File:UL350iS ULPower aircraft engine.jpg|left|thumb|A [[ULPower Aero Engines|ULPower UL]]350iS horizontally opposed air-cooled aero engine]]{{Empty section|date=March 2025}}

====H configuration engine====
{{main|H engine}}{{Empty section|date=March 2025}}

====Radial engine====
[[File:Pratt & Whitney R-2800 Engine 1.jpg|thumb|right|A [[Pratt & Whitney R-2800]] engine]]
{{main|Radial engine}}{{Empty section|date=March 2025}}

====Rotary engine====
[[File:Le Rhone 9C.jpg|thumb|right|Le Rhone 9C rotary aircraft engine]]
{{main|Rotary engine}}

Rotary engines have the cylinders in a circle around the crankcase, as in a radial engine, (see above), but the crankshaft is fixed to the airframe and the propeller is fixed to the engine case, so that the crankcase and cylinders rotate. The advantage of this arrangement is that a satisfactory flow of cooling air is maintained even at low airspeeds, retaining the weight advantage and simplicity of a conventional air-cooled engine without one of their major drawbacks.
The first practical rotary engine was the [[Gnome Omega]] designed by the Seguin brothers and first flown in 1909. Its relative reliability and good power to weight ratio changed aviation dramatically.<ref>{{cite book|title=Aviation|last=Gibbs-Smith|first= C.H.|publisher=NMSO|location=London|year=2003|isbn= 1-9007-4752-9 |page=175}}</ref>

====Wankel engine====
{{main|Wankel engine}}
[[File:WankelPP.jpg|thumb|upright|right|Powerplant from a [[Schleicher ASH 26]]e self-launching [[motor glider]], removed from the glider and mounted on a test stand for maintenance at the [[Alexander Schleicher GmbH & Co]] in [[:de:Poppenhausen (Wasserkuppe)|Poppenhausen]], [[Germany]]. Counter-clockwise from top left: propeller hub, mast with belt guide, radiator, Wankel engine, muffler shroud.]]

The [[Wankel engine|Wankel]] is a type of rotary engine. The [[Wankel engine]] is about one half the weight and size of a traditional [[four-stroke cycle]] [[piston engine]] of equal power output, and much lower in complexity. In an aircraft application, the power-to-weight ratio is very important, making the Wankel engine a good choice. Because the engine is typically constructed with an aluminium housing and a steel rotor, and aluminium expands more than steel when heated, a Wankel engine does not seize when overheated, unlike a piston engine. This is an important safety factor for aeronautical use. Considerable development of these designs started after [[World War II]], but at the time the aircraft industry favored the use of [[turbine]] engines. It was believed that [[turbojet]] or [[turboprop]] engines could power all aircraft, from the largest to smallest designs. The Wankel engine did not find many applications in aircraft, but was used by [[Mazda]] in a popular line of [[sports cars]]. The French company [[Citroën]] had developed Wankel powered {{Interlanguage link|Citroën RE-2|fr|3=Citroën RE-2|lt=RE-2}} [[helicopter]] in 1970's.<ref name="PBoulay">{{Cite book|language=fr|first=Pierre|last=Boulay|title=Les hélicoptères français|editor=Guides Larivière|year=1998|publisher=Larivière (Editions) |isbn=978-2-907051-17-0}}</ref>

In modern times the Wankel engine has been used in [[motor glider]]s where the compactness, light weight, and smoothness are crucially important.<ref>{{cite web
|url = http://www.alexander-schleicher.de/englisch/produkte/ash26/e_ash26_main.htm
| publisher = Alexander Schleicher | title = ASH 26 E Information
|access-date = 2006-11-24 | location = DE
|archive-url = https://web.archive.org/web/20061008125929/http://www.alexander-schleicher.de/englisch/produkte/ash26/e_ash26_main.htm |archive-date = 2006-10-08}}</ref>

====Combustion cycles====
Starting in the 1930s attempts were made to produce a practical [[aircraft diesel engine]]. In general, Diesel engines are more reliable and much better suited to running for long periods of time at medium power settings. The lightweight alloys of the 1930s were not up to the task of handling the much higher [[compression ratio]]s of diesel engines, so they generally had poor power-to-weight ratios and were uncommon for that reason, although the [[Clerget aircraft engines|Clerget 14F Diesel radial engine]] (1939) has the same power to weight ratio as a gasoline radial. Improvements in Diesel technology in automobiles (leading to much better power-weight ratios), the Diesel's much better fuel efficiency and the high relative taxation of AVGAS compared to Jet A1 in Europe have all seen a revival of interest in the use of diesels for aircraft. [[Thielert]] Aircraft Engines converted Mercedes Diesel automotive engines, certified them for aircraft use, and became an OEM provider to Diamond Aviation for their light twin. Financial problems have plagued Thielert, so Diamond's affiliate&nbsp;— Austro Engine&nbsp;— developed the new [[Austro Engine E4|AE300 turbodiesel]], also based on a Mercedes engine.<ref>{{cite web
|url = http://www.flyingmag.com/pilot-reports/pistons/diamond-twins-reborn
|title = Diamond Twins Reborn
|publisher = Flying Mag
|access-date = 2010-06-14
|archive-url = https://web.archive.org/web/20140618032748/http://www.flyingmag.com/pilot-reports/pistons/diamond-twins-reborn
|archive-date = 2014-06-18
|url-status = dead
}}</ref>

===Power turbines===

====Turboprop====
[[File:Turboprop cutaway.jpg|thumb|right|Cutaway view of a [[Garrett AiResearch TPE-331|Garrett TPE-331]] turboprop engine showing the gearbox at the front of the engine]]
{{main|Turboprop}}{{Empty section|date=March 2025}}

====Turboshaft====
[[File:Allison (MTU) 250 C20B.jpg|thumb|left|An [[Allison Model 250]] turboshaft engine common to many types of helicopters]]
{{main|Turboshaft}}{{Empty section|date=March 2025}}

===Electric power===
A number of electrically powered aircraft, such as the [[QinetiQ Zephyr]], have been designed since the 1960s.<ref name = french /><ref>{{Citation|url=http://www.physorg.com/printnews.php?newsid=101391900 |title=Superconducting Turbojet |publisher=[[Physorg.com]] |url-status=dead |archive-url=https://web.archive.org/web/20080223113129/http://www.physorg.com/printnews.php?newsid=101391900 |archive-date=2008-02-23 }}.</ref> Some are used as military [[Unmanned aerial vehicle|drone]]s.<ref>{{Citation|url=http://www.litemachines.com/mil/mil_main.htm |publisher=Litemachines |title=Voyeur |url-status=dead |archive-url=https://web.archive.org/web/20091231174446/http://www.litemachines.com//mil//mil_main.htm |archive-date=2009-12-31 }}.</ref> In [[France]] in late 2007, a conventional light aircraft powered by an 18&nbsp;kW electric motor using lithium polymer batteries was flown, covering more than {{convert|50|km|mi|sp=us}}, the first electric airplane to receive a [[certificate of airworthiness]].<ref name=french>{{Citation|url=http://www.apame.eu/AA%20Projects.html|title=Worldwide première: first aircraft flight with electrical engine |publisher=Association pour la Promotion des Aéronefs à Motorisation Électrique |date=December 23, 2007 |url-status=dead |archive-url=https://web.archive.org/web/20080110092518/http://www.apame.eu/AA%20Projects.html |archive-date=2008-01-10}}.</ref>

On 18 May 2020, the [[Pipistrel E-811]] was the first electric aircraft engine to be awarded a [[type certificate]] by [[EASA]] for use in [[general aviation]]. The E-811 powers the [[Pipistrel Velis Electro]].<ref name="E811_TCDS">{{cite web |title=TCDS for E811 engine, model 268MVLC |url=https://www.easa.europa.eu/sites/default/files/dfu/E.234%20TCDS%20Pipistrel%20electric%20engine%20E-811_Issue%2001.pdf |website=European Union Aviation Safety Agency |access-date=18 August 2020 |date=18 May 2020}}</ref><ref name="E811_Flyer">{{cite news |last1=Calderwood |first1=Dave |title=Pipistrel offers type certified electric motor |url=https://www.flyer.co.uk/pipistrel-offers-type-certified-electric-motor-to-others/ |access-date=18 August 2020 |agency=FLYER Magazine |publisher=Seager Publishing |date=9 July 2020}}</ref>

Many big companies, such as Siemens, are developing high performance electric engines for aircraft use, also, SAE shows new developments in elements as pure Copper core electric motors with a better efficiency. A hybrid system as emergency back-up and for added power in take-off is offered for sale by Axter Aerospace, Madrid, Spain.<ref>[http://axteraerospace.com/ Axter Aerospace]</ref>

==Reaction engines==
{{main|Jet engine}}{{Empty section|date=March 2025}}

===Jet turbines===

====Turbojet====
[[File:J85 ge 17a turbojet engine.jpg|thumb|right|A [[General Electric J85]]-GE-17A turbojet engine. This cutaway clearly shows the 8 stages of [[axial compressor]] at the front (left side of the picture), the [[combustion chamber]]s in the middle, and the two stages of [[turbine]]s at the rear of the engine.]]
{{main|Turbojet}}{{Empty section|date=March 2025}}

====Turbofan====
[[File:cfm56-3-turbofan.jpeg|thumb|left|A cutaway of a [[CFM International CFM56|CFM56-3]] turbofan engine]]
{{main|Turbofan}}{{Empty section|date=March 2025}}

==== Advanced technology engine ====
{{Main|Advanced technology engine}}
The term ''advanced technology engine'' refers to the modern generation of jet engines.<ref>{{cite book |title=A Dictionary of Aviation |first=David W. |last=Wragg |isbn=9780850451634 |edition=first |publisher=Osprey |year=1973 |page=4}}</ref>

===Pulsejets===
{{Main|Pulsejet}}{{Empty section|date=March 2025}}

====Gluhareff Pressure Jet====
{{Main|Gluhareff Pressure Jet}}{{Empty section|date=March 2025}}

===Rocket===
[[File:XLR-99 Rocket Engine USAF.jpg|thumb|right| An [[Reaction Motors XLR-99|XLR99]]]]
{{main|Rocket engine}}{{Empty section|date=March 2025}}

====Rocket turbine engine====
{{main|Rocket turbine engine}}
A rocket turbine engine is a combination of two types of propulsion engines: a [[liquid-propellant rocket]] and a turbine jet engine. Its [[power-to-weight ratio]] is a little higher than a regular jet engine, and works at higher altitudes.<ref>"Analysis of the effect of factors on the efficiency of liquid rocket turbine" by  Zu, Guojun; Zhang, Yuanjun ''Journal of Propulsion Technology ''  no. 6, p. 38-43, 58.[http://adsabs.harvard.edu/abs/1992JPT......R..38Z]</ref>

===Precooled jet engines===
{{main|Precooled jet engine}}{{Empty section|date=March 2025}}

===Piston-turbofan hybrid===

At the April 2018 [[ILA Berlin Air Show]], [[Munich]]-based research institute [[:de:Bauhaus Luftfahrt]] presented a high-efficiency composite cycle engine for 2050, combining a [[geared turbofan]] with a [[piston engine]] core.<!--<ref name=Flight24apr2018>-->
The 2.87 m diameter, 16-blade fan gives a 33.7 ultra-high [[bypass ratio]], driven by a geared low-pressure turbine but the high-pressure compressor drive comes from a piston-engine with two 10 piston banks without a high-pressure turbine, increasing efficiency with non-stationary [[Isochoric process|isochoric]]-[[isobaric process|isobaric]] combustion for higher peak pressures and temperatures.<!--<ref name=Flight24apr2018>-->
The 11,200&nbsp;lb (49.7&nbsp;kN) engine could power a 50-seat [[regional jet]].<ref name=Flight24apr2018>{{cite news |url= https://www.flightglobal.com/news/articles/hybrid-geared-fan-and-piston-concept-could-slash-fue-447955/ |title= Hybrid geared-fan and piston concept could slash fuel-burn |date= 24 April 2018 |author= David Kaminski-Morrow |work= Flightglobal}}</ref>

Its cruise [[Thrust specific fuel consumption|TSFC]] would be 11.5 g/kN/s (0.406&nbsp;lb/lbf/hr) for an overall [[engine efficiency]] of 48.2%, for a burner temperature of {{cvt|1700|K|C}}, an [[overall pressure ratio]] of 38 and a peak pressure of {{cvt|30|MPa|bar}}.<ref>{{cite web |url= https://www.bauhaus-luftfahrt.net/fileadmin/user_upload/CCE_Data_Sheet.pdf |title= Composite Cycle Engine concept technical data sheet |publisher= Bauhaus Luftfahrt}}</ref>
Although engine weight increases by 30%, [[Fuel economy in aircraft|aircraft fuel consumption]] is reduced by 15%.<ref>{{cite web |url= https://www.bauhaus-luftfahrt.net/en/research/energy-technologies-power-systems/the-composite-cycle-engine-concept/ |title= The composite cycle engine concept  |publisher= Bauhaus Luftfahrt}}</ref>
Sponsored by the [[European Commission]] under Framework 7 project {{abbr|LEMCOTEC|Low Emission Core Engine Technologies}}, Bauhaus Luftfahrt, [[MTU Aero Engines]] and [[GKN Aerospace]] presented the concept in 2015, raising the overall engine pressure ratio to over 100 for a 15.2% fuel burn reduction compared to 2025 engines.<ref>{{cite journal |url= https://www.researchgate.net/publication/278674579 |title= A Composite Cycle Engine Concept with Hecto-Pressure Ratio |date= July 2015 |doi= 10.2514/6.2015-4028 |journal= AIAA Propulsion and Energy Conference |author= Sascha Kaiser|isbn= 978-1-62410-321-6 |display-authors=et al}}</ref>

==Engine position numbering==
[[File:Throttle Boeing 727.jpg|thumb|The [[thrust lever]]s of a three-engine [[Boeing 727]], each one bearing the respective engine number]]
On multi-engine aircraft, engine positions are numbered from left to right from the point of view of the pilot looking forward, so for example on a four-engine aircraft such as the [[Boeing 747]], engine No. 1 is on the left side, farthest from the fuselage, while engine No. 3 is on the right side nearest to the fuselage.<ref>{{cite book
| title = Skyways for business
| author = ((National Business Aircraft Association))
| publisher = Henry Publications
| year = 1952
| volume = 11
| page = 52
| url = https://books.google.com/books?id=t20PAAAAIAAJ&q=inboard
}}</ref>

In the case of the twin-engine [[English Electric Lightning]], which has two fuselage-mounted jet engines one above the other, engine No. 1 is below and to the front of engine No. 2, which is above and behind.<ref>{{cite web |title=English Electric Lightning F53 (53-671) – Power Plants |url=http://www.gatwick-aviation-museum.co.uk/lightning/power_plants.htm |website=Gatwick Aviation Museum |access-date=9 June 2018 |archive-url=https://web.archive.org/web/20180612141820/http://www.gatwick-aviation-museum.co.uk/lightning/power_plants.htm |archive-date=12 June 2018 |url-status=dead }}</ref>

==Fuel==
Refineries blend Avgas with [[tetraethyllead]] (TEL) to achieve these high octane ratings, a practice that governments no longer permit for gasoline intended for road vehicles. The shrinking supply of TEL and the possibility of environmental legislation banning its use have made a search for replacement fuels for [[general aviation]] aircraft a priority for pilots’ organizations.<ref>{{cite press release|url=http://www.eaa.org/communications/eaanews/pr/011207_lawrence.html |title=EAA'S Earl Lawrence Elected Secretary of International Aviation Fuel Committee |url-status=dead |archive-url=https://web.archive.org/web/20130303034122/http://www.eaa.org/communications/eaanews/pr/011207_lawrence.html |archive-date=March 3, 2013 }}</ref>

[[Model aircraft]] typically use [[nitro engine]]s (also known as "glow engines" due to the use of a [[Glow plug (model engine)|glow plug]]) powered by [[glow fuel]], a mixture of [[methanol]], [[nitromethane]], and lubricant. Electrically powered model airplanes<ref>{{cite web|url=http://www.nitroplanes.com/rtf.html|title=Electric Airplanes - RTF|website=www.nitroplanes.com}}</ref> and helicopters are also commercially available. Small [[multicopter]] [[UAV]]s are almost always powered by electricity,<ref>{{cite web|url=https://www.amazon.com/Photography-Drones-Store-Buying-Guide/b?ie=UTF8&node=13407343011|title=Amazon.com: Photography Drones Store: Buying Guide: Electronics|website=Amazon}}</ref><ref>{{cite web|url=http://www.nitroplanes.com/quadcopters.html|title=RC Quadcopters|website=www.nitroplanes.com}}</ref> but larger gasoline-powered designs are under development.<ref>{{cite web|url=http://www.gizmag.com/yeair-hybrid-two-stroke-combustion-quadcopter-drone/37713/|title=Yeair! hybrid gasoline/electric quadcopter boasts impressive numbers|website=www.gizmag.com|date=27 May 2015 }}</ref><ref>{{cite web|url=https://hackaday.io/project/1230-goliath-a-gas-powered-quadcopter|title=Goliath – A Gas Powered Quadcopter|website=hackaday.io}}</ref>
<ref>{{cite web|url=http://www.industrytap.com/heavy-lifting-quadcopter-lifts-50-pound-loads-its-a-gas-powered-hulk-hlq/2182|title=Heavy Lifting Quadcopter Lifts 50 Pound Loads. It's a Gas Powered HULK (HLQ)|website=Industry Tap|date=2013-03-11}}</ref>

==See also==
* [[Aviation safety]]
* [[Engine configuration]]
* [[Federal Aviation Regulations]]
* [[Hyper engine]]
* [[Model engine]]
* [[United States military aircraft engine designations]]

==Notes==
{{Reflist|group=nb}}

==References==
{{Reflist}}

==External links==
{{Commons category}}
{{wiktionary}}
* [http://www.aviation-history.com/index-engine.htm Aircraft Engines and Aircraft Engine Theory (includes links to diagrams)]
* [http://www.enginehistory.org/ The Aircraft Engine Historical Society]
* [http://www.jet-engine.net/ Jet Engine Specification Database]
* [https://web.archive.org/web/20110716102030/http://www.softinway.com/news/articles/Counter-Rotating-and-Traditional-Axial-Aircraft-Low-pressure-Turbines/1.asp Aircraft Engine Efficiency: Comparison of Counter-rotating and Axial Aircraft LP Turbines]
*[http://www.flightglobal.com/pdfarchive/view/1935/1935%20-%201222.html The History of Aircraft Power Plants Briefly Reviewed : From the " 7 lb. per h.p" Days to the " 1 lb. per h.p" of To-day]
*[http://www.flightglobal.com/pdfarchive/view/1954/1954%20-%200959.html "The Quest for Power"] a 1954 ''Flight'' article by [[Bill Gunston]]
* {{cite magazine |url= https://www.flightglobal.com/pdfarchive/view/1997/1997%20-%202471.html |title= Engine Directory |magazine= Flight International |date= 24 September 1997}}

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{{DEFAULTSORT:Aircraft Engine}}
[[Category:Aircraft engines| ]]
[[Category:Powered flight|Engine]]