The Napier Rapier was a British 16-cylinder H pattern air-cooled

aero engine An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Most aircraft engines are either piston engines or gas turbines, although a few have been rocket powered and in recent years many ...

Frank Halford Major Frank Bernard Halford CBE FRAeS (7 March 1894 – 16 April 1955) was an English aircraft engine designer. He is best known for the series of de Havilland Gipsy engines, widely used by light aircraft in the 1920s and 30s. Career Educat ...

and built by Napier & Son shortly before World War II.

Design and development

The Rapier was the first of Napier's H cylinder engines. The rationale for the H is fairly straightforward, in that rather than having an engine with fewer large cylinders, more small cylinders could simply be added. It was believed that an H pattern engine would provide substantially more power and higher RPM's for the same frontal area as a large liquid-cooled V engine. The maximum RPM in a dive was 4,800. The H-block has a compact layout, as it essentially consists of two vertically opposed inline engines lying one beside another driving side by side crankshafts. Another advantage is that since the cylinders are opposed, the motion in one is balanced by the opposite motion in the one on the opposite side, leading to very smooth running. The Rapier suffered many of the same problems as the later

Dagger A dagger is a fighting knife with a very sharp point and usually two sharp edges, typically designed or capable of being used as a thrusting or stabbing weapon.State v. Martin, 633 S.W.2d 80 (Mo. 1982): This is the dictionary or popular-use de ...

and

Sabre A sabre ( French: �sabʁ or saber in American English) is a type of backsword with a curved blade associated with the light cavalry of the early modern and Napoleonic periods. Originally associated with Central European cavalry such as th ...

engines. The Fairey Seafox and

Short S.20 The Short Mayo Composite was a Piggy-back (transportation), piggy-back long-range seaplane/flying boat Composite aircraft, combination produced by Short Brothers to provide a reliable long-range air transport service to North America and, pote ...

were both powered by the Napier Rapier.

Applications

''List from Lumsden''. * Airspeed AS.5C Courier (1 built, later re-engined) * Blackburn H.S.T.10 (1 built) * Bristol Bulldog TM (1 used as testbed) *

de Havilland DH.77 The de Havilland DH.77 was a prototype British fighter aircraft of the late 1920s. Intended as a fast climbing interceptor for Britain's Royal Air Force, the DH.77 was a lightweight low-wing monoplane powered by a relatively low power engine. ...

(1 built) * Fairey Seafox (66 built) * Saro Cloud A.19/1 (1 built as engine test-bed) * Short S.20 Mercury (1 built)

Engines on display

*A preserved Rapier engine is on static display at the

Shuttleworth Collection The Shuttleworth Collection is a working aeronautical and automotive collection located at the Old Warden Aerodrome, Old Warden in Bedfordshire, England. It is the oldest in the world and one of the most prestigious, due to the variety of old a ...

, Bedfordshire, England.Ogilvy 1989, ch.4.

Specifications (Rapier V)

References

Notes

Bibliography

*Gunston, Bill. ''World Encyclopedia of Aero Engines: From the Pioneers to the Present Day''. 5th edition, Stroud, UK: Sutton, 2006. * Lumsden, Alec. ''British Piston Engines and Their Aircraft''. Marlborough, UK: Airlife Publishing, 2003. . * Ogilvy, David. ''Shuttleworth - The Historic Aeroplanes''. Shrewsbury, UK: Airlife Publishing, 1989 *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.

External links

British aero-engine data table - Oldengine.org
{{Napierengines Rapier Boxer engines 1920s aircraft piston engines H engines