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 RB211 turn Rolls-Royce from a significant player in the aero-engine industry into a global leader. Already in the early 1970s, the engine was reckoned by the company to be capable of at least 50 years of continuous development. The RB211 was officially superseded in the 1990s by the Rolls-Royce Trent family of engines, the conceptual offspring of the RB211. In 1966, American Airlines announced a requirement for a new short-medium range airliner with a focus on low-cost per-seat operations. While it was looking for a twin-engined plane, the aircraft manufacturers needed more than one customer to justify developing a new airliner.