RAF 4
title: "RAF 4" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["1910s-aircraft-piston-engines", "v12-aircraft-engines"] topic_path: "general/1910s-aircraft-piston-engines" source: "https://en.wikipedia.org/wiki/RAF_4" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::data[format=table title="infobox aero engine"]
| Field | Value |
|---|---|
| name | RAF 4 |
| image | RAF4engine.JPG |
| caption | Preserved RAF 4a engine at the Science Museum (London) |
| engine_type | Piston inline aero engine |
| manufacturer | Royal Aircraft Factory |
| designer | A.J. Rowledge |
| first_run | December 1914 |
| major_applications | Royal Aircraft Factory R.E.8 |
| number_built | 3,600 |
| developed_from | RAF 1 |
| :: |
|name=RAF 4 |image=RAF4engine.JPG |caption=Preserved RAF 4a engine at the Science Museum (London) |engine_type=Piston inline aero engine |manufacturer=Royal Aircraft Factory |designer=A.J. Rowledge |first_run=December 1914 |major_applications=Royal Aircraft Factory R.E.8 |number_built = 3,600 |developed_from = RAF 1 |developed_into = |variants_with_their_own_articles =
The RAF 4 is a British air-cooled, V12 engine developed for aircraft use during World War I. Based on the eight–cylinder RAF 1 it was designed by the Royal Aircraft Factory but produced by the two British companies of Daimler and Siddeley-Deasy. The RAF 5 was a pusher version of the same engine.
Turbocharger
A turbocharged experimental version of the RAF 4, the RAF 4d, was developed using a Rateau exhaust-driven turbocharger. The engine was test-flown in a R.E.8, but the turbocharging experiments were abandoned after the turbine failed on 4 May 1918.
Variants
;RAF 4 :1914 - Prototype engine, 140 horsepower (104 kW). ;RAF 4a :1917 - Main production variant, 150 horsepower (112 kW). 3,608 built. ;RAF 4d :1916 - 180 horsepower (134 kW), experimental supercharger installation. 16 built. ;RAF 4e :1917 - 240 horsepower (180 kW), strengthened cylinders and enlarged valves. ;RAF 5 :1915 - 150 horsepower (112 kW), pusher version with fan-cooling. ;RAF 5b :170 horsepower (127 kW), increased bore version of RAF 5.
Applications
RAF 4
::figure[src="https://upload.wikimedia.org/wikipedia/commons/0/0e/Royal_Aircraft_Factory_RE8_1.jpg" caption="The Royal Aircraft Factory R.E.8"] ::
- Armstrong Whitworth F.K.8
- Bristol F.2 Fighter
- Royal Aircraft Factory B.E.12
- Royal Aircraft Factory R.E.7
- Royal Aircraft Factory R.E.8
- Siddeley-Deasy R.T.1
- Vickers F.B.14
RAF 5
Engines on display
A preserved RAF 4a engine is on public display at the Science Museum (London).
Specifications (RAF 4a)
and start a new, fully-formatted line with -- |ref=Lumsden |type=12-cylinder, upright, 60-degree Vee engine |bore=3.94 in (100 mm) |stroke=5.51 in (140 mm) |displacement=806.15 cu in (13.2 L) |length= |diameter= |width= |height= |weight=680 lb (308 kg) |valvetrain=EOI (side-valve inlet, exhaust overhead) |supercharger= |turbocharger= |fuelsystem=Twin Claudel-Hobson Mk.1A carburettors |fueltype= |oilsystem= |coolingsystem=Air-cooled |power=163 hp (122 kW) at 1,800 rpm (takeoff power) |specpower=0.2 hp/cu in (9.2 kW/L) |compression=4.3:1 |fuelcon= |specfuelcon= |oilcon= |power/weight=0.24 hp/lb (0.4 kW/kg)
|reduction_gear=0.5:1, Left-hand tractor
|general_other= |components_other= |performance_other=
References
Notes
Bibliography
- Gunston, Bill. World Encyclopaedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989.
- Hare, Paul R. The Royal Aircraft Factory. London: Putnam, 1990.
- Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. .
References
- Gunston, 1989, p. 156.
- Hare 1990, p. 265
- Lumsden 2003, p. 224.
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