# Bentley BR2 > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Bentley_BR2 > Markdown URL: https://mediated.wiki/source/Bentley_BR2.md > Source: https://en.wikipedia.org/wiki/Bentley_BR2 > Source revision: 1329884469 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) 1910s British piston aircraft engine BR.2 B.R.2 engine on display at the RAF Museum London Type Rotary engine National origin United Kingdom Manufacturer Humber, Crossley, Daimler, Gwynnes, Ruston and Proctor First run 1917 Major applications Sopwith Snipe Number built 2,567 Developed from Bentley BR.1 The **Bentley B.R.2** was a nine-cylinder British [rotary](/source/Rotary_engine) [aircraft engine](/source/Aircraft_engine) developed during the [First World War](/source/World_War_I) by the motor car engine designer [W. O. Bentley](/source/W._O._Bentley) from his earlier [Bentley BR.1](/source/Bentley_BR1). The BR.2 was built in small numbers during the war, its main use being by the [Royal Air Force](/source/Royal_Air_Force) in the early 1920s.[1] ## Design and development The initial variant of the BR.2 developed 230 hp (170 kW), with nine cylinders measuring 5.5 in × 7.1 in (140 mm × 180 mm) for a total displacement of 1,522 cu in (24,940 cm3). It weighed 490 lb (220 kg), only 93 lb (42 kg) more than the [Bentley BR.1](/source/Bentley_B.R.1). This was the last type of rotary engine to be adopted by the RAF – later air-cooled aircraft engines such as the [Cosmos Jupiter](/source/Bristol_Jupiter) and [Armstrong Siddeley Jaguar](/source/Armstrong_Siddeley_Jaguar) being almost entirely of the fixed [radial](/source/Radial_engine) type. With the BR.2, the rotary engine had reached a point beyond which this type of engine could not be further developed, due to its inherent limitations.[2] ## Applications The type selected as the standard single-seat fighter of the post-war RAF, the [Sopwith Snipe](/source/Sopwith_Snipe), had been designed around the BR.2, as had its [ground attack](/source/Ground_attack) version, the [Sopwith TF.2 Salamander](/source/Sopwith_Salamander). A number of other experimental and minor production types were either designed for, or otherwise fitted with this power plant during the late "war" years and into the early 1920s. [Gloster Nightjar](/source/Gloster_Nightjar) during evaluation at Farnborough in 1922 - [Armstrong Whitworth Armadillo](/source/Armstrong_Whitworth_Armadillo) - [Austin Osprey](/source/Austin_Osprey) - [Boulton Paul Bobolink](/source/Boulton_Paul_Bobolink) - [Brennan Helicopter](/source/Brennan_Helicopter) - [Gloster Grouse](/source/Gloster_Grouse) - [Gloster Nightjar](/source/Gloster_Nightjar) - [Gloster Sparrowhawk](/source/Gloster_Sparrowhawk) - [Grain Griffin](/source/Port_Victoria_Grain_Griffin) - [Handley Page Type S](/source/Handley_Page_Type_S) - [Nieuport Nightjar](/source/Nieuport_Nightjar) - [Parnall Panther](/source/Parnall_Panther) - [Sopwith Buffalo](/source/Sopwith_Buffalo) - [Sopwith Gnu](/source/Sopwith_Gnu) - [Sopwith Salamander](/source/Sopwith_Salamander) - [Sopwith Snipe](/source/Sopwith_Snipe) - [Vickers Vampire](/source/Vickers_Vampire) ## Variants **BR.2 230** - 1918, 230 hp. **BR.2 245** - 1918, 245 hp. ## Engines on display A Bentley BR.2 is on public display in the [Science Museum (London)](/source/Science_Museum_(London)), another forms part of the aero engine collection at the [Royal Air Force Museum Cosford](/source/Royal_Air_Force_Museum_Cosford). Another one (serial number 40543, manufactured by Gwynnes) is in the [National Military Museum, Romania](/source/National_Military_Museum%2C_Romania). The sole operational BR.2 is mounted in [Fantasy of Flight](/source/Fantasy_of_Flight)'s replica of the [Sopwith Snipe](/source/Sopwith_Snipe).[3] A ¼ scale working replica of the Bentley BR.2 World War I rotary aero engine built by Lewis Kinleside Blackmore is currently on display at the Bentley Memorial Building in Oxfordshire, UK. This was the first model built of this engine and is the subject also of a book by L K Blackmore. The Canada Aviation and Space Museum in Ottawa, Ontario, Canada has a BR.2 installed in their Sopwith 7F.1 Snipe. ## Specifications (BR.2) Manufacturer's plate (dated November 1917) and valve operating gear of the BR.2 engine on display at the [Royal Air Force Museum Cosford](/source/Royal_Air_Force_Museum_Cosford) *Data from* *Jane's* [4] ### General characteristics - **Type:** 9-cylinder rotary - **[Bore](/source/Bore_(engine)):** 5.51 in (140 mm) - **[Stroke](/source/Stroke_(engine)):** 7.09 in (180 mm) - **[Displacement](/source/Engine_displacement):** 1521.8 in (24.94 L) - **[Dry weight](/source/Dry_weight):** 490 lb (220 kg) ### Components - **[Valvetrain](/source/Valvetrain):** Overhead valve - **Cooling system:** Air-cooled ### Performance - **Power output:** 250 hp - **Fuel consumption:** 20 gallons per hour - **Oil consumption:** 16 pints per hour - **[Power-to-weight ratio](/source/Power-to-weight_ratio):** 0.5 hp/lb ## See also **Related development** - [Bentley BR.1](/source/Bentley_BR1) - [Clerget](/source/Clerget) **Comparable engines** - [Le Rhône](/source/Le_Rh%C3%B4ne) **Related lists** - [List of aircraft engines](/source/List_of_aircraft_engines) ## References ### Notes 1. **[^](#cite_ref-1)** Lumsden 2003, p.88. 1. **[^](#cite_ref-2)** Gunston 1989, p.22. 1. **[^](#cite_ref-3)** Archived at [Ghostarchive](https://ghostarchive.org/varchive/youtube/20211211/fUQCqSw-Yds) and the [Wayback Machine](https://web.archive.org/web/20160418094859/https://www.youtube.com/watch?v=fUQCqSw-Yds): [*Sopwith Snipe - Part 1 - Kermie Cam*](https://www.youtube.com/watch?v=fUQCqSw-Yds&t=346s). *[YouTube](/source/YouTube)*. 1. **[^](#cite_ref-4)** Jane's 1993, p.274. ### Bibliography - Gunston, Bill (1986). *World Encyclopedia of Aero Engines*. Wellingborough: Patrick Stephens. pp. 25–26. - Gunston, Bill. *World Encyclopedia of Aero Engines*. Cambridge, England. Patrick Stephens Limited, 1989. [ISBN](/source/ISBN_(identifier)) [1-85260-163-9](https://en.wikipedia.org/wiki/Special:BookSources/1-85260-163-9) - *Jane's Fighting Aircraft of World War I*. London. Studio Editions Ltd, 1993. [ISBN](/source/ISBN_(identifier)) [1-85170-347-0](https://en.wikipedia.org/wiki/Special:BookSources/1-85170-347-0) - Lumsden, Alec. *British Piston Engines and their Aircraft*. Marlborough, Wiltshire: Airlife Publishing, 2003. [ISBN](/source/ISBN_(identifier)) [1-85310-294-6](https://en.wikipedia.org/wiki/Special:BookSources/1-85310-294-6). ## External links Wikimedia Commons has media related to [Bentley BR2](https://commons.wikimedia.org/wiki/Category:Bentley_BR2). - [National Museum of the USAF - BR.2 fact sheet](https://web.archive.org/web/20071212200433/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=812) --- Adapted from the Wikipedia article [Bentley BR2](https://en.wikipedia.org/wiki/Bentley_BR2) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Bentley_BR2?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.