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 new V8 engine began in 1952, bearing no relation to the 1905 version apart from its V8 configuration. Rolls-Royce purchased Bentley in 1931 and the new engine was intended for use in both Rolls-Royce and Bentley automobiles. The result was a series of V8 engines known internally as the "L410", the name relating to its bore size of 4.10 inches, in accordance with the company practice. Despite some attempts at changing the naming convention, the engine has kept both the 4.10 inch bore and the name L410 throughout its life, with the exception of the odd prototype. Continuous improvement saw