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.
– 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.
– high compression version of the Python I with high compression pistons and compression ratio increased to 5.3:1.
– 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.
– modified version of the Hispano-Suiza 8B.
– modified and improved version of the Adder I.
– modified and improved version of the Adder II with balanced crankshaft.
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.[1]