High Quality Content by WIKIPEDIA articles! The Miles M.9 Master was a British 2-seat monoplane advanced trainer built by Miles Aircraft Ltd for the Royal Air Force and Fleet Air Arm during the Second World War. It went through a number of variants according to engine availability and was even modified as an emergency fighter during the Battle of Britain. It was a fast, strong and fully aerobatic aircraft and served as an excellent introduction to the high performance British fighter aircraft of the day; the Spitfire and Hurricane. The M.9A Master I was based on the M.9 Kestrel trainer that was first demonstrated at the Hendon Airshow in July 1937, although it never entered production. The M.9 Kestrel, powered by the 745 hp (555 kW) Rolls- Royce Kestrel XVI V-12 engine, could reach 295 mph (475 km/h). The production Master I, which first flew on 31 March, 1939, used the lower powered 715 hp (535 kW) Rolls-Royce Kestrel XXX engine, reducing the maximum speed. Nonetheless it remained one of the fastest and most maneuverable trainers of its day.