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 AE 2100 Rolls-Royce AE 2100 The Rolls-Royce AE 2100 is a turboprop developed by Allison Engine Company, now part of Rolls-Royce North America. A derivative of the Allison AE 1107C-Liberty (Rolls-Royce T406) turboshaft engine, the AE 2100 shares the same high-pressure core as that engine, as does the Rolls-Royce AE 3007 turbofan. The engine is a two-shaft design, and was the first to use dual FADECs (full authority digital engine control) to control both engine and propeller. There are four variants of the engine: the civil AE2100A, and the military variants which include the AE 2100D2/D2A, AE 2100D3, AE 2100J and AE