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 Holdings however, obliged to set up a proxy board to manage Allison and had also to set up a separate company, Allison Advanced Development Company, Inc., to manage classified programmes ""that involve leading-edge technologies"" such as the Joint Strike Fighter program. In 2000, this restriction was replaced by a more flexible Special Security Arrangement. In 2001, Rolls-Royce and its LiftSystem was among the group that won the JSF contract for the F-35. The Allison acquisition, at $525 million (equivalent to £328 million), brought four new engine types into the Rolls-Royce civil engine portfolio on seven platforms and several light aircraft applications.