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/SNECMA M45H The engine had a low turbine entry temperature and comparatively low rotational speed. The engine was designed to be uprated without drastic redesign. Three options were water injection (+10% thrust), improved HP turbine (+10% thrust), addition of a zero-stage to the LP compressor (+25% thrust). The engine was developed at the time of the Rolls-Royce bankruptcy which resulted in delays in developing the engine. A Rolls-Royce/SNECMA M45H engine is on display as part of the aero engine collection at the Royal Air Force Museum Cosford. Rolls-Royce/SNECMA M45H The Rolls-Royce/SNECMA M45H was a medium bypass ratio turbofan produced specifically for the