Rolls-Royce Limited increase its own production rates. By the late 1920s, aero engines made up most of Rolls-Royce's business. Henry Royce's last design was the Merlin aero engine, which was first flown in prototype form in 1935, although he had died in 1933. This was developed from the R engine, which had powered a record-breaking Supermarine S.6B seaplane to almost in the 1931 Schneider Trophy. The Merlin was a powerful supercharged V12 engine and was fitted into many World War II aircraft: the British Hawker Hurricane, Supermarine Spitfire, de Havilland Mosquito (twin-engine), Avro Lancaster (four-engine) (a development of the Avro Manchester with
Rolls-Royce V8 engine later taken back by the factory and scrapped. The other two were used for factory transport or display purposes. Rolls ordered three more chassis for delivery in 1906 but there is no evidence these were ever made. No example of a 1905 V-8 car or engine is known to survive. Although the 1905 V-8 cannot be judged a success, lessons learned from the engine were used in subsequent Rolls-Royce engine designs. Having used straight six, straight eight and V-12 engines in the interim period, the need for another new engine was recognised in the early 1950s. Development of a totally