Wolseley Viper

The Wolseley Viper is a British-built, high-compression derivative of the Hispano Suiza HS-8 liquid-cooled V-8 engine, built under licence by Wolseley Motors during World War I.

It powered later models of the S.E.5a, SPAD VII and other British or British-built aircraft designed for the Hispano-Suiza.

Variants

Wolseley W.4A Python I (1917)

150 hp (110 kW) – licence produced version of the Hispano-Suiza 8Aa with minor structural changes and the weight increased to 455 lb (206 kg), retained the original's low compression 1.8 in (45 mm) pistons and compression ratio of 4.7:1. Only 100 built.^[1]^[2]

Wolseley W.4A Python II

180 hp (130 kW) – high compression version of the Python I with high compression 2 in (50 mm) pistons and compression ratio increased to 5.3:1.^[2]

Wolseley W.4A* Viper (1918)

200 hp (150 kW) – broadly the equivalent of the Hispano-Suiza 8Ab, compression ratio of 5.3:1 (19 early production engines had a higher compression ratio of 5.6:1), with 200 hp English Hispano propeller hubs.^[3]

Wolseley W.4B Adder I (1918)

200 hp (150 kW) – modified version of the Hispano-Suiza 8B.^[3]^[4]

Wolseley W.4B* Adder II

200 hp (150 kW) – modified and improved version of the Adder I.^[3]

Wolseley W.4B* Adder III

200 hp (150 kW) – modified and improved version of the Adder II with balanced crankshaft.^[3]

Applications

Survivors

A Wolseley Viper powered Royal Aircraft Factory S.E.5a is owned by, and on display at The Shuttleworth Collection, Old Warden Aerodrome in the UK.^[5]

Engines on display

A preserved Wolseley Viper is on public display at the Science Museum, London.
A preserved Wolseley Viper is on public display at the Museo Nacional de Aeronáutica de Argentina

Specifications (W.4A Viper)

Data from Gunston^[1] and Lumsden^[3]

General characteristics

Type: 8-cylinder, upright, 90 degree Vee engine
Bore: 4.72 in (120 mm)
Stroke: 5.12 in (130 mm)
Displacement: 716.8 cu in (11.7 L)
Length: 46.2 in (1,170 mm)
Width: 33.5 in (850 mm)
Height: 35.4 in (900 mm)
Dry weight: 455 lb (206 kg)

Components

Fuel system: Twin Zenith-Duplex carburettors
Cooling system: Liquid-cooled
Reduction gear: Direct drive, Right-hand tractor

Performance

Power output: 200–210 hp (150–160 kW)
Compression ratio: 5.3:1

References

Wikimedia Commons has media related to Wolseley Viper.

Notes

^ a b Gunston (1986), p. 76.
^ a b Lumsden (1994), pp. 156 & 232.
^ a b c d e Lumsden (1994), p. 232.
^ Gunston (1986), p. 171.
^ The Shuttleworth Collection - SE5a Archived 23 July 2019 at the Wayback Machine www.shuttleworth.org Retrieved: 09 March 2017.

Bibliography

Gunston, Bill (1986). World Encyclopaedia of Aero Engines. Wellingborough: Patrick Stephens Ltd. ISBN 0-85059-717-X.
Lumsden, Alec (1994). British Piston Engines and Their Aircraft. Shrewsbury: Airlife Publishing Ltd. ISBN 1-85310-294-6.