Editing Bristol Centaurus

{{short description|1930s British piston aircraft engine}}
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{{Use dmy dates|date=December 2016}}
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{|{{Infobox aircraft begin
 |name = Centaurus
 |image = File:Bristol Centaurus FAAM.jpg
 |caption = Bristol Centaurus on display at the [[Fleet Air Arm Museum]]
}}{{Infobox aircraft engine
 |type = [[Piston]] [[aircraft engine]]
 |manufacturer = [[Bristol Aeroplane Company]]
 |first run = July 1938
 |major applications = [[Hawker Tempest]]<br />[[Bristol Brabazon]]<br />[[Vickers Warwick]]<br />[[Hawker Sea Fury]]<br /> [[Airspeed Ambassador]]
 |number built = c. 2,500
 |program cost =
 |unit cost =
 |developed from =
 |developed into =
 |variants with their own articles =
}}
|}

The '''Centaurus''' was the final development of the [[Bristol Aeroplane Company|Bristol Engine Company]]'s series of [[sleeve valve]] [[radial engine|radial]] [[aircraft engine]]s. The Centaurus is an 18-cylinder, two-row design that eventually delivered over {{cvt|3000|hp}}. The engine was introduced into service late in the [[Second World War]] and was one of the most powerful aircraft piston engines to see service.

==Design and development==

Like other Bristol sleeve valve engines, the Centaurus was based on the design knowledge acquired from an earlier design, in this case the [[Bristol Perseus]] cylinder. The Centaurus used 18 Perseus cylinders.   The same cylinder was in use in the contemporary 14-cylinder [[Bristol Hercules|Hercules]], which was being brought into production when the design of the Centaurus started.<ref>{{cite book| title=Fedden-the life of Sir Roy Fedden |first=Bill |last=Gunston |date=1998 |publisher=Rolls-Royce Heritage Trust |series=Historical Series No 26 |isbn=1872922139 |pages=175,179}}</ref>
[[File:Sleeve Valve Closeup.JPG|thumb|left|Sectioned cylinder showing sleeve valve]]
The Centaurus had a cylinder swept volume of {{cvt|3272|cuin|L|1}},  nearly as much as the American {{cvt|3347.9|cuin|L|1}} [[Wright R-3350 Duplex-Cyclone|Wright R-3350 ''Duplex-Cyclone'']] large radial, making the Centaurus one of the largest aircraft piston engines to enter production, while that of the Hercules was {{cvt|2363|cuin|L|1}}. The nearly 40 per cent higher capacity was achieved by increasing the stroke from {{convert|6.5|to|7|in|mm|sigfig=3}} and by changing to two rows of nine cylinders instead of two rows of seven. The diameter of the Centaurus was only just over 6 per cent greater than the Hercules in spite of its much greater swept volume.<ref name="Jane's">Bridgman (Jane's) 1998, p. 270.</ref>

The cylinder heads had an indentation like an inverted top hat, which was finned, but it was difficult to get air down into this hollow to adequately cool the head. During development, Bristol contacted [[ICI Metals Division]], Birmingham, to enquire whether a copper-chromium alloy with higher thermal conductivity would have sufficient high temperature strength to be used for this purpose. With the same cylinder volume and using the new material, the horsepower per cylinder was raised from {{cvt|110|hp}} to {{cvt|220|hp}}.

Bristol maintained the Centaurus from type-testing in 1938, but production did not start until 1942, owing to the need to get the Hercules into production and improve the reliability of the entire engine line.<ref name="Jane's"/>  Nor was there any real need for the larger engine at this early point in the war, when most military aircraft designs had a requirement for engines of about {{cvt|1000|hp|0}}. The Hercules power of about {{cvt|1500|hp|0}} was better suited to the existing airframes.

The Centaurus did not enter service until near the end of the war, first appearing on the [[Vickers Warwick]]. Other wartime, or postwar, uses included the [[Bristol Brigand]] and [[Bristol Buckmaster|Buckmaster]], [[Hawker Tempest]] and [[Hawker Sea Fury|Sea Fury]] and the [[Blackburn Firebrand]] and [[Blackburn Beverley|Beverley]]. The engine also entered service after the war in a civilian airliner, the [[Airspeed Ambassador]] and was also used in the [[Bristol Brabazon]] I Mark 1 prototype aircraft until the Brabazon trans-Atlantic airliner programme was cancelled. The eight Centaurus engines were to be replaced with eight [[Bristol Proteus]] gas turbines on the Mark II giving a {{cvt|100|mph}} faster cruising speed at {{cvt|10000|ft}} higher altitude.<ref>{{cite book |title=Bristol Brabazon |first=Graham M. |last=Simons |date=2012 |publisher=History Press Limited |isbn=9780752467337 |page=100}}</ref> By the end of the war in Europe, around 2,500 examples of the Centaurus had been produced by Bristol.<ref name="Jane's"/>

The 373 was the most powerful version of the Centaurus and was intended for the Blackburn Beverley transport aircraft. Using direct fuel injection, it achieved a remarkable {{cvt|3220|hp}}, but was never fitted.<ref>{{Cite magazine |url=http://www.flightglobal.com/pdfarchive/view/1956/1956%20-%200572.html |title=Aero Engines 1956 |work=Flight |date= 11 May 1956 |accessdate= 12 December 2014 |archive-url=https://web.archive.org/web/20160827083642/http://www.flightglobal.com/pdfarchive/view/1956/1956%20-%200572.html |archive-date=2016-08-27 |page=572}}</ref> A projected enlarged capacity version of the Centaurus was designed by Sir [[Roy Fedden]]; cylinders were produced for this engine, but it was never built. Known as the Bristol Orion, a name used previously for a variant of the Jupiter engine and  [[Bristol Orion|later re-used for a turboprop]], this development was also a two-row, 18 cylinder sleeve valve engine, with the displacement increased to {{cvt|4142|cuin|1}} [{{cvt|6.25|×|7.5|in}}], nearly as large as the American [[Pratt & Whitney R-4360 Wasp Major]] four-row, 28-cylinder radial, the largest displacement aviation radial engine ever placed in quantity production.<ref>Gunston 2006, p.152.</ref>

==Variants==
'''Centaurus I''' – {{cvt|2000|hp|kW}}, two-speed full/medium [[supercharger]] and left-hand tractor drive. Run on 100 [[Octane rating|octane]] fuel.{{sfnp|Lumsden|1994|p=125}}

'''Centaurus IV''' – {{cvt|2300|hp|kW}}, two-speed medium/full supercharger and rigid mounting.{{sfnp|Lumsden|1994|p=125}}

'''Centaurus V''' – {{cvt|2500|hp|kW}}, two-speed full/medium supercharger with cropped [[impeller]]s. The '''Centaurus VI''' was similar to the Centaurus V with master connecting rods in cylinder numbers 7 and 8. The '''Centaurus VIII''' was similar to the Centaurus VI with methanol/water fittings.{{sfnp|Lumsden|1994|p=125}}

'''Centaurus VII''' – {{cvt|2400|hp|kW}}, two-speed medium/full supercharger and rigid mounting.{{sfnp|Lumsden|1994|p=125}}

'''Centaurus IX''' – {{cvt|2500|hp|kW}}, and '''Centaurus XI''' were similar to the Centaurus VII. The '''Centaurus X''' was similar to the Centaurus IX with methanol/water fittings.{{sfnp|Lumsden|1994|pp=125–126}}

'''Centaurus XII''' – {{cvt|2300|hp|kW}}, was a development of the Centaurus IV with twin-turbine entry supercharger, redesigned propeller reduction gear and Hobson-[[Royal Aircraft Establishment|RAE]] injector and vertically mounted [[starter motor]]. The '''Centaurus XV''' was a development of the Centaurus VII with flexible mounting.{{sfnp|Lumsden|1994|p=126}}

'''Centaurus XVIII''' – {{cvt|2470|hp|kW}}, was similar to the Centaurus XV.{{sfnp|Lumsden|1994|p=126}}

'''Centaurus XX''' – {{cvt|2360|hp|kW}}, a dual-installation engine for the [[Bristol Brabazon]], similar to the Centaurus 57.{{sfnp|Lumsden|1994|p=126}}

'''Centaurus 57''' – {{cvt|2470|hp|kW}}, a development of the Centaurus XII with modified supercharger and injector. The '''Centaurus 58''' was a modified Centaurus 57, and the '''Centaurus 59''' was a modified Centaurus 58 with a flexible mounting.{{sfnp|Lumsden|1994|p=126}}

'''Centaurus 70''' – {{cvt|2470|hp|kW}}, a modified Centaurus 57 with single-speed medium supercharger. The '''Centaurus 71''' was a lightened Centaurus 70 with [[torquemeter]]-type reduction gear and {{cvt|150|hp|kW}} accessory drive.{{sfnp|Lumsden|1994|p=127}}

'''Centaurus 100''' – {{cvt|2470|hp|kW}}, a modified Centaurus 57 with two-speed full/medium supercharger and methanol/water injector. The '''Centaurus 130''' was a civil model, modified from the Centaurus 100 with single-speed medium supercharger.{{sfnp|Lumsden|1994|p=127}}

'''Centaurus 160''' – {{cvt|2625|hp|kW}}, two-speed full/medium supercharger, a front cover suitable for braking propeller, front ignition, {{cvt|150|hp|kW}} accessory drive, improved sleeve timing and dynamic suspension mounting. The '''Centaurus 161''' was a Centaurus 160 with torquemeter-type reduction gear. The '''Centaurus 165''' was a Centaurus 161 with improved power section and methanol/water fittings.{{sfnp|Lumsden|1994|p=127}}

'''Centaurus 170''' – {{cvt|2625|hp|kW}}, a development of the Centaurus 160 with single-speed medium supercharger. The '''Centaurus 171''' was a Centaurus 170 with torquemeter-type reduction gear. The '''Centaurus 173''' was a Centaurus 171 with methanol/water injection and accessory drive. The '''Centaurus 175''' was a Centaurus 173 with modified valve port timings and reduced boost.{{sfnp|Lumsden|1994|p=127}}

'''Centaurus 373''' – {{cvt|2370|hp|kW}}, a modified Centaurus 173.{{sfnp|Lumsden|1994|p=127}}

'''Centaurus 568''' – {{cvt|2470|hp|kW}}, a civil engine with two-speed full/medium supercharger modified from the Centaurus 58.{{sfnp|Lumsden|1994|p=127}}

'''Centaurus 630''' – {{cvt|2450|hp|kW}}, civil engine with single-speed medium supercharger, a front cover suitable for braking propeller, front ignition, {{cvt|150|hp|kW}} accessory drive, improved sleeve timing and dynamic suspension mounting. The '''Centaurus 631''' was a Centaurus 630 with torquemeter-type reduction gear.{{sfnp|Lumsden|1994|p=127}}

'''Centaurus 660''' – {{cvt|2625|hp|kW}}, civil engine with two-speed full/medium supercharger, a front cover suitable for braking propeller, front ignition, {{cvt|150|hp|kW}} accessory drive, improved sleeve timing and dynamic suspension mounting. The '''Centaurus 661''' was a Centaurus 660 with torquemeter-type reduction gear. The '''Centaurus 662''' was a Centaurus 660 with methanol/water injection for improved takeoff power, the '''Centaurus 663''' was a Centaurus 662 with torquemeter-type reduction gear.{{sfnp|Lumsden|1994|p=128}}

==Applications==
[[File:Fairey Spearfish.jpg|thumb|right|Bristol Centaurus powered [[Fairey Spearfish]]]]
''Note:''<ref>List from Lumsden</ref>
{{columns-list|colwidth=30em|
* [[Airspeed Ambassador]]
* [[Blackburn Beverley]]
* [[Blackburn Firebrand]]
* [[Blackburn Firecrest]]
* [[Breda-Zappata BZ.308|Breda BZ.308]]
* [[Bristol Brabazon]]
* [[Bristol Brigand]]
* [[Bristol Buckingham]]
* [[Bristol Buckmaster]]
* [[Fairey Spearfish]]
* [[Folland Fo.108]] (the Fo.108 was a testbed aircraft for various engines)
* [[Hawker Sea Fury|Hawker Fury & Sea Fury]]
* [[Hawker Tempest]]
* [[Hawker Tornado]]
* [[Short Shetland]]
* [[Vickers Warwick]]
}}

==Survivors==
The [[Royal Navy Historic Flight]] operated a Hawker Sea Fury powered by a Bristol Centaurus engine<ref>[http://www.royalnavy.mod.uk/operations-and-support/establishments/naval-bases-and-air-stations/rnas-yeovilton/royal-navy-historic-flight/ Royal Navy Historic Flight - Aircraft] {{webarchive |url=https://web.archive.org/web/20090615075917/http://www.royalnavy.mod.uk/operations-and-support/establishments/naval-bases-and-air-stations/rnas-yeovilton/royal-navy-historic-flight/ |date=15 June 2009 }} Retrieved: 5 August 2009</ref> until it was destroyed in an accident on 28 April 2021 whilst attempting a forced landing following a failure and seizure of its Bristol Centaurus XVIII engine:

https://assets.publishing.service.gov.uk/media/628cd96cd3bf7f1f47c65ebc/Hawker_Sea_Fury_T_Mk_20_G-RNHF_07-22.pdf

==Engines on display==
Preserved Bristol Centaurus engines are on public display at the following museums:
* [[Aerospace Bristol]]
* [[Aerospace Museum of California]]
* [[Fleet Air Arm Museum]]
* [[Imperial War Museum Duxford]]
* [[London Science Museum]]
* [[Midland Air Museum]]
* [[Shuttleworth Collection|Shuttleworth Collection, Old Warden]]
* [[Dumfries and Galloway Aviation Museum]]
* [[San Diego Air & Space Museum]]

==Specifications (Centaurus VII)==
[[File:BristolCentaurus.JPG|thumb|right|{{center|A Centaurus with cylinders removed exposing the [[sleeve valve]]s.}}]]
{{pistonspecs
|<!-- If you do not understand how to use this template, please ask at [[Wikipedia talk:WikiProject Aircraft]] -->
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|ref=''British Piston Engines and Their Aircraft''{{sfnp|Lumsden|1994|p=125}}
|type=18-cylinder, air-cooled, two-row [[radial engine]]
|bore={{cvt|5.75|in|mm}}
|stroke={{cvt|7.00|in|mm}}
|displacement={{cvt|3270|cuin|L}}
|length=
|diameter={{cvt|55.3|in|mm}}
|width=
|height=
|weight={{cvt|2695|lb}}
|valvetrain=[[Sleeve valve]], four ports per sleeve
|supercharger=Two-speed centrifugal, single stage
|turbocharger=
|fuelsystem=Injection
|fueltype=100/130 [[Octane rating|Octane]] [[petrol]]
|oilsystem=Direct-pressure lubrication
|coolingsystem=Air-cooled
|power={{cvt|2520|hp}} at 2,700 rpm
|specpower={{cvt|0.77|hp/cuin|kW/L|1}}
|compression=7.2:1
|fuelcon=
|specfuelcon=
|oilcon=
|power/weight={{cvt|0.94|hp/lb|kW/kg|2}}
}}

==See also==
{{aircontent
<!-- other related articles that have not already linked: -->
|see also=

<!-- designs which were developed into or from this aircraft: -->
|related=
* [[Bristol Hercules]]
<!-- aircraft that are of similar role, era, and capability this design: -->
|similar aircraft=

<!-- relevant lists that this aircraft appears in: -->
|lists=
* [[List of aircraft engines]]
<!-- For aircraft engine articles.  Engines that are of similar to this design: -->
|similar engines=
* [[Alfa Romeo 135]]
* [[Nakajima Homare]]
* [[Pratt & Whitney R-2800 Double Wasp]]
* [[Wright R-3350 Duplex-Cyclone]]
* [[Shvetsov ASh-73]]

<!-- See [[WP:Air/PC]] for more explanation of these fields. -->
}}

==References==

===Notes===
{{reflist}}

===Bibliography===
* Bridgman, L, (ed.) (1998) ''Jane's Fighting Aircraft of World War II''. Crescent. {{ISBN|0-517-67964-7}}
* Gunston, Bill. ''Development of Piston Aero Engines''. Cambridge, UK. Patrick Stephens, 2006. {{ISBN|0-7509-4478-1}}
* Gunston, Bill. ''World Encyclopedia of Aero Engines: From the Pioneers to the Present Day''. 5th edition, Stroud, UK: Sutton, 2006.{{ISBN|0-7509-4479-X}}
* {{cite book |last=Lumsden |first=Alec |date=1994 |title=British Piston Engines and Their Aircraft |location=Shrewsbury |publisher=Airlife Publishing Ltd |isbn=1-85310-294-6}}.
* White, Graham. ''Allied Aircraft Piston Engines of World War II: History and Development of Frontline Aircraft Piston Engines Produced by Great Britain and the United States During World War II''. Warrendale, Pennsylvania: SAE International, 1995. {{ISBN|1-56091-655-9}}

==External links==
{{Commons category|Bristol Centaurus}}
* [http://www.flightglobal.com/pdfarchive/view/1949/1949%20-%200969.html Period advertisement for the Bristol Centaurus - ''Flight'', May 1949]
* [https://www.youtube.com/watch?v=GH2FBuDv_dE&t=28s Video of a cutaway engine in motion illustrating its operation]

{{Bristol aeroengines}}

[[Category:Aircraft air-cooled radial piston engines]]
[[Category:Bristol aircraft engines|Centaurus]]
[[Category:Sleeve valve engines]]
[[Category:1930s aircraft piston engines]]