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 – licence produced version of the Hispano-Suiza 8Aa with minor structural changes and the weight increased to 455 lb, retained the original's low compression 45 mm pistons and compression ratio of 4.7:1. Only 100 built.


 * Wolseley W.4A Python II
 * 180 hp – high compression version of the Python I with high compression 50 mm pistons and compression ratio increased to 5.3:1.


 * Wolseley W.4A* Viper (1918)
 * 200 hp – 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.


 * Wolseley W.4B Adder I (1918)
 * 200 hp – modified version of the Hispano-Suiza 8B.


 * Wolseley W.4B* Adder II
 * 200 hp – modified and improved version of the Adder I.


 * Wolseley W.4B* Adder III
 * 200 hp – modified and improved version of the Adder II with balanced crankshaft.

Applications

 * Airco DH.9
 * Avro 552
 * Bristol M.R.1
 * Bristol Tourer
 * Cierva C.8
 * Martinsyde F.6
 * Royal Aircraft Factory S.E.5a
 * Sopwith Antelope
 * Sopwith Cuckoo

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.

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