View source for Napier Sabre

{{short description|1930s British aircraft piston engine}}
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{{Use dmy dates|date=December 2017}}
{{Use British English|date=December 2017}}
{{infobox aero engine
 |name = Sabre
 |image = Napier Sabre01.jpg
 |caption = Napier Sabre cutaway at the London Science Museum.
 |engine_type=[[Coolant#Liquids|Liquid-cooled]] [[H engine|H-24]] [[sleeve valve]] [[Reciprocating engine|piston]] [[Aircraft engine|aero engine]]
 |manufacturer=[[D. Napier & Son]]
 |national_origin=[[United Kingdom]]
 |first_run=January 1938
 |major_applications= {{ubl | [[Hawker Tempest]] | [[Hawker Typhoon]] | [[Napier-Heston Racer]] }}
 |number_built =
 |developed_from =
 |variants_with_their_own_articles =
 |developed_into =
}}

The '''Napier Sabre''' is a British [[H engine|H-24-cylinder]], [[coolant|liquid-cooled]], [[sleeve valve]], [[piston]] [[aircraft engine|aero engine]], designed by [[Frank Halford|Major Frank Halford]] and built by [[D. Napier & Son]] during [[World War II]]. The engine evolved to become one of the most powerful [[Inline engine (aviation)|inline]] piston aircraft engines in the world, developing from {{convert|2,200|hp|kW|abbr=on}} in its earlier versions to {{convert|3500|hp|abbr=on}} in late-model prototypes.

The first prototype powered by the Sabre was the [[Napier-Heston Racer]], in an attempt to capture the world speed record. The first production aircraft to be powered by the Sabre were the [[Hawker Typhoon]] and [[Hawker Tempest]].{{#tag:ref|The Napier-Heston Racer used the first production Sabre engine. The world-record contender crashed during early tests and the project was discontinued.|group=nb}} Other aircraft using the Sabre were early prototype and production variants of the [[Blackburn Firebrand]], the [[Martin-Baker MB 3]] prototype and a [[Hawker Sea Fury|Hawker Fury]] prototype. The rapid introduction of [[jet engine]]s after the war led to the quick demise of the Sabre, as there was less need for high power military piston aero engines and because Napier turned its attention to developing [[turboprop]] engines such as the [[Napier Naiad|Naiad]] and [[Napier Eland|Eland]].

==Design and development==
Prior to the Sabre, Napier had been working on large aero engines for some time. Its most famous was the [[Napier Lion|Lion]], which had been a very successful engine between the World Wars and in modified form had powered several of the [[Supermarine]] [[Schneider Trophy]] competitors in 1923 and 1927, as well as several [[land speed record]] cars. By the late 1920s, the Lion was no longer competitive and work started on replacements.

Napier followed the Lion with two [[H engine|H-block]] designs: the H-16 [[Napier Rapier|Rapier]] and the H-24 [[Napier Dagger|Dagger]]. The H-block has a compact layout, consisting of two horizontally opposed engines, one atop or beside the other. Since the cylinders are opposed, the motion in one is balanced by the motion on the opposing side, eliminating both first order and second order vibration. In these new designs, Napier chose air cooling but in service, the rear cylinders proved to be impossible to cool properly, which made the engines unreliable.

===Genesis===
[[File:Napier-Heston racer.jpg|thumb|The first aircraft designed around the Sabre engine – the [[Napier-Heston Racer]] which crashed during early flight tests.]]
During the 1930s, studies showed the need for engines capable of developing one horsepower per cubic inch of displacement (about 45&nbsp;kW/[[litre]]). Such power output was needed to propel aircraft large enough to carry large fuel loads for long range flights. A typical large engine of the era, the [[Pratt & Whitney R-1830]] ''Twin Wasp'', developed about {{convert|1,200|hp|kW|abbr=on}} from 1,830 [[cubic inch]]es (30 litres), so an advance of some 50 per cent would be needed. This called for radical changes and while many companies tried to build such an engine, none succeeded.{{Citation needed|date=March 2011}}

In 1927, [[Harry Ricardo]] published a study on the concept of the [[sleeve valve]] engine. In it, he wrote that traditional [[poppet valve]] engines would be unlikely to produce much more than {{convert|1,500|hp|kW|abbr=on}}, a figure that many companies were eyeing for next generation engines. To pass this limit, the sleeve valve would have to be used, to increase [[volumetric efficiency]], as well as to decrease the engine's sensitivity to detonation, which was prevalent with the poor quality, low-octane fuels in use at the time.<ref>Engines and Enterprise: The Life and Work of Sir Harry Ricardo, John Reynolds, 1999 {{ISBN|978-0750917124}}, p.145</ref> Halford had worked for Ricardo 1919–1922 at its London office{{#tag:ref|21 Suffolk St, Westminster, London, a little cul-de-sac off Pall Mall East.|group=nb}} and Halford's 1923 office was in Ladbroke Grove, North Kensington, only a few miles from Ricardo, while Halford's 1929 office was even closer (700 yards),<ref>Engines and Enterprise: The Life and Work of Sir Harry Ricardo, John Reynolds, 1999 {{ISBN|978-0750917124}}, p.103</ref><ref>Boxkite to Jet - the remarkable career of Frank B Halford, Douglas Taylor, 1999,{{ISBN|1 872922 16 3}}, p.73</ref> and while in 1927 Ricardo started work with [[Bristol Aeroplane Company|Bristol Engines]] on a line of sleeve-valve designs,<ref>Engines and Enterprise: The Life and Work of Sir Harry Ricardo, John Reynolds, 1999 {{ISBN|978-0750917124}}, p.186</ref> Halford started work with Napier,<ref>Boxkite to Jet - the remarkable career of Frank B Halford, Douglas Taylor, 1999,{{ISBN|1 872922 16 3}}, p.81</ref> using the Dagger as the basis. The layout of the H-block, with its inherent balance and the Sabre's relatively short stroke, allowed it to run at a higher rate of rotation, to deliver more power from a smaller displacement, provided that good volumetric efficiency could be maintained (with better breathing), which sleeve valves could do.<ref>Engines and Enterprise: The Life and Work of Sir Harry Ricardo, John Reynolds, 1999 {{ISBN|978-0750917124}}, p.187</ref>

The Napier company decided first to develop a large 24 cylinder liquid–cooled engine, capable of producing at least {{convert|2,000|hp|kW|abbr=on}} in late 1935. Although the company continued with the opposed H layout of the Dagger, this new design positioned the cylinder blocks horizontally and it was to use sleeve valves.<ref name="Flight309">[F C Sheffield] 23 March 1944. "[http://www.flightglobal.com/pdfarchive/view/1944/1944%20-%200072.html 2,200 h.p. Napier Sabre ]" ''Flight'', p. 309. www.flightglobal.com. Retrieved: 9 November 2009.</ref> All of the accessories were grouped conveniently above and below the cylinder blocks, rather than being at the front and rear of the engine, as in most contemporary designs.<ref name="Flight309"/>

The Air Ministry supported the Sabre programme with a development order in 1937 for two reasons: to provide an alternative engine if the [[Rolls-Royce Vulture]] and the [[Bristol Centaurus]] failed as the next generation of high power engines and to keep Napier in the aero-engine industry.<ref>Industry and Air Power The Expansion Of British Aircraft Production 1935-1941, Sebastian Ritchie 2007, Routledge Taylor and Francis Group, {{ISBN|0-7146-4343-2}}, p.140</ref>
The first Sabre engines were ready for testing in January 1938, although they were limited to {{convert|1,350|hp|kW|abbr=on}}. By March, they were passing tests at {{convert|2,050|hp|kW|abbr=on}} and by June 1940, when the Sabre passed the [[Air Ministry]]'s 100-hour test, the first production versions were delivering {{convert|2,200|hp|kW|abbr=on}} from their 2,238 cubic inch (37 litre) displacements.<ref name="Flight309"/> By the end of the year, they were producing {{convert|2,400|hp|kW|abbr=on}}. The contemporary 1940 [[Rolls-Royce Merlin]] II was generating just over {{convert|1,000|hp|kW|abbr=on}} from a 1,647 cubic inch (27 litre) displacement.

===Production===
[[File:Hawker Typhoon 2 ExCC.jpg|thumb|The [[Hawker Typhoon]] was the first operational Sabre-powered aircraft, entering service with the RAF in mid-1941. Problems with both the Sabre engine and the airframe nearly led to the Typhoon's withdrawal from service.]]
Problems arose as soon as mass production began. Prototype engines had been hand-assembled by Napier craftsmen and it proved to be difficult to adapt it to assembly-line production techniques. The sleeves often failed due to the way they were manufactured from chrome-molybdenum steel, leading to seized cylinders, which caused the loss of the sole prototype [[Martin-Baker MB 3]].<ref name="Flinov45">Flight 1945, p.550.</ref><ref>Aeroplane 2010, pp. 65–66.</ref> The Ministry of Aircraft Production was responsible for the development of the engine and arranged for sleeves to be machined by the [[Bristol Aeroplane Company]] from its Taurus engine forgings. These nitrided austenitic steel sleeves were the result of many years of intensive sleeve development, experience that Napier did not have. Air filters had to be fitted when a new sleeve problem appeared in 1944 when aircraft were operating from Normandy soil with its abrasive, gritty dust.<ref>I Kept No Diary-60 Years with Marine Diesels, Automobile and Aero Engines, F.R. Banks 1978, Airlife Publications, {{ISBN|0 9504543 9 7}}, p.133</ref>

Quality control proved to be inadequate, engines were often delivered with improperly cleaned castings, broken piston rings and machine cuttings left inside the engine.<ref name="tempest">[http://www.hawkertempest.se/NapierSabre1.htm Napier Sabre] {{webarchive|url=https://web.archive.org/web/20120623153341/http://www.hawkertempest.se/NapierSabre1.htm |date=23 June 2012 }} Retrieved on 17 July 2009.</ref> Mechanics were overworked trying to keep the Sabres running and during cold weather they had to run them every two hours during the night so that the engine oil would not congeal and prevent the engine from starting the next day.{{#tag:ref|Unlike current "multigrade" [[motor oil]]s, the lubricants in use in the 1940s thickened up at low temperatures, thus preventing the Sabre from "picking-up" when started.|group=nb}} These problems took too long to remedy and the engine gained a bad reputation. To make matters worse, mechanics and pilots unfamiliar with the different nature of the engine, tended to blame the Sabre for problems that were caused by not following correct procedures. This was exacerbated by the representatives of the competing Rolls-Royce company, which had its own agenda. In 1944, Rolls-Royce produced a similar design prototype called the [[Rolls-Royce Eagle (1944)|Eagle]].

Napier seemed complacent and tinkered with the design for better performance. In 1942, it started a series of projects to improve its high-altitude performance, with the addition of a three-speed, two-stage [[supercharger]], when the basic engine was still not running reliably. In December 1942, the company was purchased by the [[English Electric|English Electric Company]], which ended the supercharger project immediately and devoted the whole company to solving the production problems, which was achieved quickly.

[[File:Napier Sabre on truck.png|thumb|A 2,400hp Sabre inside a mock-up of an aircraft nose, mounted on a truck for display purposes |alt=The truck has signs reading "2,400 Horsepower!! The power behind the Typhoon & Tempest fighters" and "Napier Sabre - The most powerful aero engine in service in the world", plus the Napier logo]]

By 1944, the Sabre V was delivering {{convert|2,400|hp|kW|abbr=off}} consistently and the reputation of the engine started to improve. This was the last version to enter service, being used in the [[Hawker Typhoon]] and its derivative, the [[Hawker Tempest]]. Without the advanced supercharger, the engine's performance over {{convert|20000|ft|m|abbr=on}} fell off rapidly and pilots flying Sabre-powered aircraft, were generally instructed to enter combat only below this altitude. At low altitude, both planes were formidable. As air superiority over Continental Europe was slowly gained, Typhoons were increasingly used as [[fighter-bomber]]s, notably by the [[RAF Second Tactical Air Force]]. The Tempest became the principal destroyer of the [[V-1 flying bomb]] ([[Fieseler Fi 103]]), since it was the fastest of all the Allied fighters at low levels. Later, the Tempest destroyed about 20 [[Messerschmitt Me 262]] jet aircraft.

Development continued and the later Sabre VII delivered {{convert|3,500|hp|kW|abbr=on}} with a new supercharger. By the end of World War II, there were several engines in the same power class. The [[Pratt & Whitney R-4360 Wasp Major]] four-row, 28-cylinder radial produced {{convert|3,000|hp|kW|abbr=on}} at first and later types produced {{convert|3,800|hp|kW|abbr=on}}, but these required almost twice the displacement in order to do so, 4,360 cubic inches (71 litres).

==Variants==
Note:{{#tag:ref|List from Lumsden unless otherwise noted.|group=nb}}
;Sabre I (E.107)
:(1939) {{convert|2,000|hp|kW|abbr=on}}.
;Sabre II
:(1940) {{convert|2,300|hp|kW|abbr=on}}. Experimental 0.332:1 propeller reduction gear ratio.
;Sabre II (production variant)
:{{convert|2,200|hp|kW|abbr=on}}. Reduction gear ratio 0.274:1: mainly used in early [[Hawker Typhoon]]s.<ref>Sheffield March 1944, p. 310.</ref>
;Sabre IIA
:{{convert|2,235|hp|kW|abbr=on}}. Revised ignition system: maximum boost +9 lbs.<ref>Air Ministry 1943, pp. 24, 25.</ref>
;Sabre IIB
:{{convert|2,400|hp|kW|abbr=on}}. Four choke [[SU Carburettor|S.U. carburettor]]: Mainly used in [[Hawker Tempest|Hawker Tempest V]].<ref name="Flight 1945, p. 551.">Flight 1945, p. 551.</ref>
;Sabre IIC
:{{convert|2,065|hp|kW|abbr=on}}. Similar to Mk VII.
[[File:NapierSabreIII.JPG|thumb|right|Napier Sabre III]]
;Sabre III
:{{convert|2,250|hp|kW|abbr=on}}. Similar to Mk IIA, tailored for the [[Blackburn Firebrand]]: 25 manufactured and installed.<ref name="Flight 1945, p. 551."/>
;Sabre IV
:{{convert|2,240|hp|kW|abbr=on}}. As Mk VA with Hobson fuel injection: preliminary flight development engine for Sabre V series.<ref name="Flight 1945, p. 551."/> Used in Hawker Tempest I.<ref>Mason 1991, p. 331.</ref>
;Sabre V
:{{convert|2,600|hp|kW|abbr=on}}. Developed MK II, redesigned supercharger with increased boost, redesigned induction system.
;Sabre VA
:{{convert|2,600|hp|kW|abbr=on}}. Mk V with Hobson-R.A.E fuel injection, single-lever throttle and propeller control: used in Hawker Tempest VI.
;Sabre VI
:{{convert|2,310|hp|kW|abbr=on}}. Mk VA with [[Dowty Rotol|Rotol]] cooling fan: used in 2 Hawker Tempest Vs modified to use Napier designed annular radiators; also in experimental [[Vickers Warwick|Vickers Warwick V]].<ref>Flight 1946, p. 91.</ref>
;Sabre VII
:{{convert|3,055|hp|kW|abbr=on}}. Mk VA strengthened to withstand high powers produced using [[Water injection (engines)|Water/Methanol injection]]. Larger supercharger impeller.<ref>Flight 1945, p. 552.</ref>
;Sabre VIII
:{{convert|3,000|hp|kW|abbr=on}}. Intended for [[Hawker Sea Fury|Hawker Fury]]; tested in the [[Folland Fo.108]].
;Sabre E.118
:(1941) Three-speed, two-stage supercharger, [[contra-rotating propeller]]; test flown in Fo.108.
;Sabre E.122
:(1946) 3,500 horsepower. Intended for Napier 500mph tailless fighter

==Applications==
The engine has been used in many aircraft, including two mass-produced fighters.<ref>Application lists from Lumsden</ref>

===Adopted===
* [[Hawker Tempest]]
* [[Hawker Typhoon]]

===Limited production and prototypes===
* [[Blackburn Firebrand]], only in 21 early production aircraft
* [[Fairey Battle]], test-bed
* [[Folland Fo.108]], test-bed
* [[Hawker Sea Fury|Hawker Fury]], prototype (2 built (LA610, VP207), 485&nbsp;mph)
* [[Martin-Baker MB 3]], prototype
* [[Napier-Heston Racer]], prototype
* [[Vickers Warwick]], prototype

==Restoration project and engines on display==
;Under restoration:
* [[Canadian Aviation Heritage Centre]], [[Macdonald Campus]], [[McGill University]], [[Montréal]].<ref>{{usurped|1=[https://web.archive.org/web/20080515144859/http://www.cahc-ccpa.com/workshop_one.htm CAHC "Workshop One"]}} Retrieved: 21 November 2009.</ref>
* Sabre IIa, Serial Number 2484, [[Hawker Typhoon Preservation Group]], RB396, UK
;Preserved on public display:
* [[Solent Sky]] (example on loan from [[Birmingham Museum of Science and Industry]])
* [[Fantasy of Flight]], Polk City, Florida
* A Sabre IIA engine has been restored by the Friends Association of the [[Museo Nacional de Aeronáutica de Argentina]] and is on public display at the Engines Hall.{{citation needed|date=September 2015}}
;Sectioned Napier engines on public display:
* [[Imperial War Museum Duxford|Imperial War Museum]], [[Duxford]] (donated by [[Cambridge University Engineering Department]])
* [[Royal Air Force Museum London]]
* [[Science Museum (London)|London Science Museum]]
* [[World of Wearable Art|World of WearableArt & Classic Cars Museum, Nelson]]
* [[Canada Aviation and Space Museum]], Ottawa

==Specifications (Sabre VA)==
{{pistonspecs
|<!-- If you do not understand how to use this template, please ask at [[Wikipedia talk:WikiProject Aircraft]] -->
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|ref=''Lumsden''<ref>Lumsden 2003, p.176.</ref><ref>Flight 1945, pp. 550-553.</ref>
|type=24-cylinder supercharged liquid-cooled [[H engine|H-type]] aircraft piston engine
|bore={{convert|5.0|in|mm|0|abbr=on}}
|stroke={{convert|4.75|in|mm|0|abbr=on}}
|displacement={{convert|2,240|cuin|L|abbr=on}}
|length={{convert|82.25|in|mm|abbr=on}}
|diameter=
|width={{convert|40|in|mm|abbr=on}}
|height={{convert|46|in|mm|abbr=on}}
|weight={{convert|2,360|lb|kg}}
|valvetrain=[[Sleeve valve]]
|supercharger=[[Torsion (mechanics)|Torsion]] [[Drive shaft|shaft]] drive to gear-driven, single-stage, two-speed [[centrifugal type supercharger|centrifugal supercharger]]
|turbocharger=
|fuelsystem=[[Claudel-Hobson|Hobson-R.A.E]] injection-type [[carburetor|carburettor]]
|fueltype=100/130 [[octane rating|octane]] [[gasoline|petrol]]
|oilsystem=High pressure: [[Oil pump (internal combustion engine)|Oil pump]] and full flow [[oil filter]] with three scavenge pumps
|coolingsystem=Liquid cooled: 70% water and 30% [[ethylene glycol]] coolant mixture, pressurised.
|power=
* {{convert|2,850|hp|kW|abbr=on}} at 3,800 rpm and +13 psi (0.9 bar, 56") intake boost
* {{convert|3,040|hp|kW|abbr=on}} at 4,000 rpm [[war emergency power]]
|specpower=1.36 hp/in³ (59.9 kW/L)
|compression=7:1
|fuelcon=117 gallons/hour (532 L/hr) at maximum cruise, F.S. supercharger gear; 241 gallons/hour (1,096 L/hr) at maximum combat rating, F.S. supercharger
|specfuelcon=
|oilcon= 47 pints/hour (27 L/hr) at maximum cruise 3,250 rpm and +7 psi (0.48 bar, 14"); 71 pints/hour (40 L/hr) at war emergency power
|power/weight=1.29 hp/lb (2.06 kW/kg)
}}

==See also==
{{aircontent
<!-- other related articles that have not already linked: -->
|see also=
<!-- designs which were developed into or from this aircraft: -->
|related=
<!-- aircraft that are of similar role, era, and capability as 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=
* [[Daimler-Benz DB 604]]
* [[Dobrynin VD-4K]]
* [[Junkers Jumo 222]]
* [[Lycoming H-2470]]
* [[Pratt & Whitney X-1800]]
* [[Pratt & Whitney XH-3130]]
* [[Rolls-Royce Eagle (1944)|Rolls-Royce Eagle]]
* [[Wright R-2160 Tornado]]

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

==References==

===Footnotes===
{{reflist|group=nb}}

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

===Bibliography===
* Air Ministry. ''Pilot's Notes for Typhoon Marks IA and IB; Sabre II or IIA engine (2nd edition)''. London: Crecy Publications, 2004. {{ISBN|0-85979-033-9}}
* "A Real Contender (article and images) " [http://www.aeroplanemonthly.co.uk/ Aeroplane] {{Webarchive|url=https://web.archive.org/web/20160713121211/http://www.aeroplanemonthly.co.uk/ |date=13 July 2016 }}  No. 452, Volume 38, Number 12, December 2010.
* [http://www.flightglobal.com/pdfarchive/view/1943/1943%20-%200955.html "A Co-operative Challenger (article and images on Heston Racer).]" ''[[Flight International|Flight and The Aircraft Engineer]]'' No. 1790, Volume XLIII, 15 April 1943.
* 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}}
* Lumsden, Alec. ''British Piston Engines and Their Aircraft''. Marlborough, UK: Airlife Publishing, 2003. {{ISBN|1-85310-294-6}}.
* Mason, Francis K. ''Hawker Aircraft Since 1920 (3rd revised edition)''. London: Putnam, 1991. {{ISBN|0-85177-839-9}}.
* [http://www.flightglobal.com/pdfarchive/view/1945/1945%20-%202283.html "Napier Sabre VII (article and images).]" ''[[Flight International|Flight and The Aircraft Engineer]]'' No. 1926, Volume XLVIII, 22 November 1945.
* [http://www.flightglobal.com/pdfarchive/view/1946/1946%20-%201438.html "Napier Flight Development (article and images on Napier's test and development centre).]" ''[[Flight International|Flight and The Aircraft Engineer]]'' No. 1961, Volume L, 25 July 1946.
* [[L. J. K. Setright|Setright, L. J. K.]]: ''The Power to Fly: The Development of the Piston Engine in Aviation''. Allen & Unwin, 1971. {{ISBN|0-04-338041-7}}.
* Sheffield, F. C. [http://www.flightglobal.com/pdfarchive/view/1944/1944%20-%200072.html "2,200 h.p. Napier Sabre (article and images).]" ''[[Flight International|Flight and The Aircraft Engineer]]'' No. 1829, Volume XLV, 13 January 1944.
* Sheffield, F. C. [http://www.flightglobal.com/pdfarchive/view/1944/1944%20-%200603.html "Napier Sabre II (article and images).]" ''[[Flight International|Flight and The Aircraft Engineer]]'' No. 1839, Volume XLV, 23 March 1944.
* 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}}
* Reynolds, John. ''Engines and Enterprise: The Life and Work of Sir Harry Ricardo''. Stroud, UK: Sutton, 1999. {{ISBN|978-0750917124}}
* Taylor, Douglas. ''Boxkite to Jet - the remarkable career of Frank B Halford''. Derby, UK: RRHT, 1999. {{ISBN|1 872922 16 3}}

==Further reading==
* {{Ref Jane's|||1945}} {{ISBN|0-517-67964-7}} (1989 copy by Crescent Books, NY.)
* [[Pierre Clostermann|Clostermann, Pierre]]: ''The Big Show''. London, UK: Chatto & Windus in association with William Heinemann, 1953. {{ISBN|0-297-84619-1}} (2004 edition).

==External links==
{{Commons category}}
* [http://www.npht.org/ Napier Power Heritage Trust site]
* [https://web.archive.org/web/20120409202601/http://www.khulsey.com/makoto_ouchi_napier_sabre.html Cutaway illustration of a Napier Sabre drawn by Max Millar (uncredited) and coloured in by Makoto Oiuchi]
* [http://www.airracinghistory.freeola.com/aircraft/Napier-Heston%20Racer.htm The Sabre-powered Napier-Heston Racer]
* [https://web.archive.org/web/20120623153341/http://www.hawkertempest.se/NapierSabre1.htm The Hawker Tempest Page]
* [https://web.archive.org/web/20090430152818/http://www.hawkertempest.se/Stories.htm The Greatest Engines of All Time]
* [http://www.flightglobal.com/pdfarchive/view/1946/1946%20-%201973.html ''NAPIER SABRE 3000 B.H.P''] A 1946 ''[[Flight International|Flight]]'' advertisement for the Sabre engine

{{Napierengines}}

[[Category:Napier aircraft engines|Sabre]]
[[Category:Sleeve valve engines]]
[[Category:Boxer engines]]
[[Category:1930s aircraft piston engines]]
[[Category:H engines]]