Rolls-Royce R revolutions. Although not directly related to the Spitfire, the Supermarine engineers gained valuable experience of high-speed flight with the S.5 and S.6 aircraft, their next project being the Rolls-Royce Goshawk-powered Supermarine Type 224 prototype fighter aircraft. Technological advances used in the R engine, such as sodium-cooled valves and spark plugs able to operate under high boost pressures, were incorporated into the Rolls-Royce Merlin design. The author Steve Holter sums up the design of the Rolls-Royce R with these words: The Schneider Trophy was a prestigious annual prize competition for seaplanes that was first held in 1913. The 1926 race was
Rolls-Royce 25/30 was provided. The four-speed gearbox is mounted in unit with the engine, and a traditional right-hand change used. Synchromesh is fitted to third and top gears. The riveted chassis has rigid front and rear axles suspended by half-elliptic springs with hydraulic dampers. Braking is on all four wheels assisted by a mechanical servo, famously under licence of Hispano-Suiza. Separate rear brakes are fitted for the handbrake. The traditional Rolls-Royce radiator with triangular top was used with vertical louvres, the opening angle of which is controlled thermostatically to control engine cooling. Only the chassis and mechanical parts were made by Rolls-Royce.