W12 engine

A W12 engine is a twelve cylinder piston internal combustion engine in a W configuration. W12 engines have been manufactured in two distinct configurations. The original W12 configuration used three banks of four cylinders coupled to a common crankshaft, with 60° angles between the banks. These were used in several aircraft engine designs from the 1920s, notably the Napier Lion and various French engines. The more recent configuration, used in the Volkswagen Group W12, uses four rows of three cylinders merged into two 'cylinder banks' (two narrow-angle VR6 engine blocks), coupled to a common crankshaft.

The Napier Lion was a broad arrow-style W12 engine produced by Napier at Acton, West London, from 1917 to the late 1930s. This mostly alloy engine had a capacity of 24 litres (1,465 cu in) and produced from 450 to 900 horsepower (336 to 671 kW; 456 to 912 PS). It was used in many racing cars by John Cobb and Malcolm Campbell, racing aircraft such as the Supermarine S.5 Schneider Cup winner, and speed boats such as Hubert Scott-Paine's Miss Britain III.

The 500 hp (373 kW) Farman 12We was one of their best selling engines in the 1920s. They also built a W18.

Lorraine manufactured their 12E Courlis aircraft engine in the 1920s and 1930s.

Sunbeam built a prototype W12 called the "Kaffir", based on their Arab V8 engine.

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