Napier Rapier
{{short description|1920s British piston aircraft engine}}
{{Use dmy dates|date=December 2017}}
{{Use British English|date=December 2017}}
| {{Infobox Aircraft Begin
|name=Rapier |image=NapierRapier.JPG |caption= Preserved Napier Rapier at the Shuttleworth Collection }}{{Infobox Aircraft Engine |type=Piston aero engine |manufacturer=Napier & Son |first run= 1929 |major applications=Fairey Seafox |number built = |program cost = |unit cost = |developed from = |developed into = |variants with their own articles = }} |
The Napier Rapier was a British 16-cylinder H pattern air-cooled aero engine designed by Frank Halford 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 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 and Sabre engines. The Fairey Seafox and Short S.20 were both powered by the Napier Rapier.
Applications
List from Lumsden. Lumsden 2003, pp. 172-173.
- 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 (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, Bedfordshire, England.Ogilvy 1989, ch.4.
Specifications (Rapier V)
{{pistonspecs
|
|ref=Flight and Lumsden.[http://www.flightglobal.com/pdfarchive/view/1935/1935%20-%200549.html Flight - Napier Rapier, 14 March 1935] www.flightglobal.com Retrieved: 16 January 2011Lumsden 2003, p.173.
|type=16-cylinder air-cooled H engine
|bore=3.5 in (89 mm)
|stroke=3.5 in (89 mm)
|displacement=539 cu in (8.833 litres)
|length=57.37 in (1,457 mm)
|diameter=
|width=23.37 in (594 mm)
|height=36 in (914 mm)
|weight= 720 lb (327 kg)
|valvetrain=1 inlet and 1 exhaust valve per cylinder.
|supercharger=Fully supercharged
|turbocharger=
|fuelsystem=1 Claudel carburettor
|fueltype=87 octane
|oilsystem=
|coolingsystem=Air-cooled
|power=340 hp (253.5 kW) at 4,000 rpm at 13,000 ft (3,960 m)
|specpower= 0.63 hp/cu in
|compression=6:1
|fuelcon=
|specfuelcon=
|oilcon= 8 to 12 pints (4.54 to 6.82L) per hour
|power/weight=0.47 hp/lb (0.775 kW/kg)
|reduction_gear= Left hand tractor, 2.5625:1
}}
See also
{{aircontent
|see also=
|related=
|similar aircraft=
|lists=
|similar engines=
}}
References
=Notes=
{{reflist}}
=Bibliography=
- 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}}.
- Ogilvy, David. Shuttleworth - The Historic Aeroplanes. Shrewsbury, UK: Airlife Publishing, 1989 {{ISBN|1-85310-106-0}}
- 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}}
- [http://www.oldengine.org/members/diesel/Duxford/ukaero3.htm British aero-engine data table - Oldengine.org]
{{Napierengines}}