Wolseley Viper

• Wolseley W.4A Python I (1917) – licence produced version of the Hispano-Suiza 8Aa with minor structural changes and the weight increased to , retained the original's low compression pistons and compression ratio of 4.7:1. Only 100 built. • Wolseley W.4A Python II – high compression version of the Python I with high compression pistons and compression ratio increased to 5.3:1. • Wolseley W.4A* Viper (1918) – 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) – modified version of the Hispano-Suiza 8B. • Wolseley W.4B* Adder II – modified and improved version of the Adder I. • Wolseley W.4B* Adder III – 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 ==Surviving engines==

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 ==Specifications (W.4A Viper)==