Rolls-Royce R engine was invaluable in the subsequent development of the Rolls-Royce Merlin engine and the Spitfire. A de-rated R engine, known as the Griffon, was tested in 1933, but it was not directly related to the production Rolls-Royce Griffon of 1939, of the same exact bore/stroke and resultant displacement figures as the "R" design. Three examples of the R engine are on public display in British museums as of 2014. Rolls-Royce realised that the Napier Lion engine used in the 1927 Supermarine S.5 Schneider Trophy winner had reached the peak of its development, and that for Britain's entrant in the next
Rolls-Royce Goshawk Rolls-Royce Goshawk The Rolls-Royce Goshawk was a development of the Rolls-Royce Kestrel that used evaporative or steam cooling. In line with Rolls-Royce convention of naming piston engines after birds of prey, it was named after the goshawk. The engine first ran in 1933 and provided 660 horsepower (490 kW). Only a few engines were built as the aircraft designs intended to use it were not adopted by the Royal Air Force. The Goshawk was used to power the Short Knuckleduster, the Supermarine Type 224 (a predecessor to the Supermarine Spitfire) and other prototype aircraft. The Goshawk was developed from the