Rolls-Royce aircraft piston engines test stand. The Buzzard was an enlargement of the Kestrel of Condor size, developed in its most extreme form into the Rolls-Royce R racing engine used for the Schneider Trophy competition. The Vulture of 1939 was essentially two Peregrines on a common crankshaft in an X-24 configuration, both of these types being deemed unsuccessful. The Rolls-Royce Merlin, and later the development of the Buzzard, the Rolls-Royce Griffon were the two most successful designs for Rolls-Royce to serve in the Second World War, the Merlin powering RAF fighters the Hawker Hurricane, Supermarine Spitfire, fighter/bomber de Havilland Mosquito, Lancaster and Halifax heavy
Rolls-Royce Spey Rolls-Royce Tay. Aviation versions of the "base model" Spey have accumulated over 50 million hours of flight time. In keeping with Rolls-Royce naming practices, the engine is named after the River Spey. In 1954 Rolls-Royce introduced the first commercial bypass engine, the Rolls-Royce Conway, with a 21,000 lbf (94 kN) thrust aimed at what was then the "large end" of the market. This was far too large for smaller aircraft such as the Sud Caravelle, BAC One-Eleven or Hawker Siddeley Trident which were then under design. Rolls then started work on a smaller engine otherwise identical in design derived from