The Miles M.77 Sparrowjet was a twin-engined jet-powered racing aircraft built by the British aircraft manufacturer F.G. Miles Limited. It was a one-off conversion, involving the fitting of Turbomeca Palas turbojet engines to the prototype Miles Sparrowhawk, enabling the aircraft to achieve higher performance than could be achieved with its conventional piston engine arrangement. The Sparrowhawk had been a racing aircraft developed and produced in small numbers by Miles Aircraft during the 1930s. During the late 1950s, the owner of one such aircraft, Fred Dunkerley, requested that Miles look into converting the type to use jet propulsion for greater performance. During December 1959, the company received the aircraft to perform the extensive modification programme; in addition to the installation of French Palas turbojets, the original piston engine was eliminated while the forward fuselage was entirely replaced and rebuilt with the cockpit in a more forward position. The conversion took almost three years to perform. On 14 December 1953, the completed Sparrowjet conducted its maiden flight. While the aircraft proved to be capable of speeds in excess of 200 mph, it was noted to accelerate somewhat slowly. Its owner quickly put it to use as a somewhat unique racing aircraft for the era, a factor which likely aided the Sparrowjet in multiple victories, including the SBAC Challenge Cup on 21 May 1956, and the King's Cup Race on 13 July 1957, the latter in which the aircraft had reported attained a maximum speed of 228 mph (367 km/h). However, the Sparrowjet was heavily damaged by a hangar fire while being stored at RAF Upton during July 1964, ending its racing career. Design and development During the 1930s, the British aviation company Miles Aircraft produced half a dozen Miles Sparrowhawks, a relatively successful piston-powered racing aircraft. The prototype, G-ADNL, proved itself to be a relatively fast aircraft amongst its contemporaries, being frequently raced by multiple owners throughout the late 1930s and 1940s, often emerging as the victor. During the late 1940s, it was acquired by the racing enthusiast Fred Dunkerley; he decided to approach Miles with the suggestion to convert the aircraft to harness the relatively recently discovered method of jet propulsion as a means of increasing its performance. It was quickly recognised that such a conversion would involve extensive modifications to the airframe, including the near-complete replacement of the forward fuselage and tail unit. As one means of addressing the center