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 installed in a preserved Avro York ]]

An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Aircraft using power components are referred to as powered flight.{{cite book |title=A Dictionary of Aviation |first=David W. |last=Wragg |isbn=9780850451634 |edition=first |publisher=Osprey |year=1973 |page=215}} Most aircraft engines are either piston engines or gas turbines, although a few have been rocket powered and in recent years many small UAVs have used electric motors.

Manufacturing industry

{{see also|List of aircraft engines}}The largest manufacturer of turboprop engines for general aviation is Pratt & Whitney.{{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}} General Electric announced in 2015 entrance into the market.

Development history

File:Wright Vertical Four-Cylinder Engine.jpg{{Incomplete list|date=March 2025}}{{See also|Timeline of jet power}}

1903: Manly-Balzer engine sets standards for later radial engines.{{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}}
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.{{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 }}{{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}}{{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}}{{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 }}
1914: Auguste Rateau suggests using exhaust-powered compressor – a turbocharger – to improve high-altitude performance; not accepted after the tests{{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}}
1918: Sanford Alexander Moss picks up Rateau's idea and creates the first successful turbocharger{{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}}
1926: Armstrong Siddeley Jaguar IV (S), the first series-produced supercharged engine for aircraft use.{{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}}The world's first series-produced cars with superchargers came earlier than aircraft. These were Mercedes 6/25/40 hp and Mercedes 10/40/65 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}}
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.

Shaft engines

=Reciprocating (piston) engines=

==In-line engine==

For other configurations of aviation inline engine, such as X-engines, U-engines, H-engines, etc., see Inline engine (aeronautics).{{main|Straight engine}}{{Empty section|date=March 2025}}File:Ranger L-440.jpg]]

==V-type engine==

File:Rolls-Royce Merlin.jpg

==Horizontally opposed engine==

File:UL350iS ULPower aircraft engine.jpg350iS horizontally opposed air-cooled aero engine]]{{Empty section|date=March 2025}}

==H configuration engine==

==Radial engine==

File:Pratt & Whitney R-2800 Engine 1.jpg engine]]

==Rotary engine==

File:Le Rhone 9C.jpg

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.{{cite book|title=Aviation|last=Gibbs-Smith|first= C.H.|publisher=NMSO|location=London|year=2003|isbn= 1-9007-4752-9 |page=175}}

==Wankel engine==

File:WankelPP.jpge self-launching motor glider, removed from the glider and mounted on a test stand for maintenance at the Alexander Schleicher GmbH & Co in Poppenhausen, Germany. Counter-clockwise from top left: propeller hub, mast with belt guide, radiator, Wankel engine, muffler shroud.]]

The 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 multi|Citroën RE-2|fr|3=Citroën RE-2|lt=RE-2}} helicopter in 1970's.{{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}}

In modern times the Wankel engine has been used in motor gliders where the compactness, light weight, and smoothness are crucially important.{{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}}

==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 ratios of diesel engines, so they generally had poor power-to-weight ratios and were uncommon for that reason, although the 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 — Austro Engine — developed the new AE300 turbodiesel, also based on a Mercedes engine.{{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

}}

=Power turbines=

==Turboprop==

File:Turboprop cutaway.jpg turboprop engine showing the gearbox at the front of the engine]]

==Turboshaft==

File:Allison (MTU) 250 C20B.jpg turboshaft engine common to many types of helicopters]]

=Electric power=

A number of electrically powered aircraft, such as the QinetiQ Zephyr, have been designed since the 1960s.{{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 }}. Some are used as military drones.{{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 }}. In France in late 2007, a conventional light aircraft powered by an 18 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.{{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}}.

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.{{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}}{{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}}

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.[http://axteraerospace.com/ Axter Aerospace]

Reaction engines

=Jet turbines=

==Turbojet==

File:J85 ge 17a turbojet engine.jpg-GE-17A turbojet engine. This cutaway clearly shows the 8 stages of axial compressor at the front (left side of the picture), the combustion chambers in the middle, and the two stages of turbines at the rear of the engine.]]

==Turbofan==

File:cfm56-3-turbofan.jpeg turbofan engine]]

== Advanced technology engine ==

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

=Pulsejets=

==Gluhareff Pressure Jet==

=Rocket=

File:XLR-99 Rocket Engine USAF.jpg]]

==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."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]

=Precooled jet engines=

=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.

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-isobaric combustion for higher peak pressures and temperatures.

The 11,200 lb (49.7 kN) engine could power a 50-seat regional jet.{{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}}

Its cruise TSFC would be 11.5 g/kN/s (0.406 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}}.{{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}}

Although engine weight increases by 30%, aircraft fuel consumption is reduced by 15%.{{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}}

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.{{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}}

Engine position numbering

File:Throttle Boeing 727.jpgs 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.{{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

}}

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.{{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 }}

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.{{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 }}

Model aircraft typically use nitro engines (also known as "glow engines" due to the use of a glow plug) powered by glow fuel, a mixture of methanol, nitromethane, and lubricant. Electrically powered model airplanes{{cite web|url=http://www.nitroplanes.com/rtf.html|title=Electric Airplanes - RTF|website=www.nitroplanes.com}} and helicopters are also commercially available. Small multicopter UAVs are almost always powered by electricity,{{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}}{{cite web|url=http://www.nitroplanes.com/quadcopters.html|title=RC Quadcopters|website=www.nitroplanes.com}} but larger gasoline-powered designs are under development.{{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 }}{{cite web|url=https://hackaday.io/project/1230-goliath-a-gas-powered-quadcopter|title=Goliath – A Gas Powered Quadcopter|website=hackaday.io}}

{{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}}

Notes

References

External links

[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}}

Engine