Background The
M.9A Master I was based on the privately developed
M.9 Kestrel trainer that was first demonstrated at the
Hendon Air show in July 1937, although this aircraft never entered production. The M.9 Kestrel, powered by a single
Rolls-Royce Kestrel XVI V-12 engine, capable of generating up to 745
hp (555 kW), could attain a maximum speed of 296 mph (477 km/h).
Into flight On 31 March 1939, the first true production Master I conducted its
maiden flight. The first production examples were delivered during late July of that year. The Master had entered RAF service just prior to the start of the Second World War. Eventually, 900 Mk. I and Mk. IA Masters were constructed. This total included 26 built as the M.24 Master Fighter which were modified to a single-seat configuration, and armed with six
.303 in machine guns for use as an
emergency fighter; this model never saw combat use. When production of the Kestrel engine ceased, a new variant of the Master was designed that used an air-cooled
Bristol Mercury XX radial engine, capable of producing 870 hp (650 kW), instead. Thus configured, on 30 October 1939, the first
M.19 Master II prototype made its first flight; 1,748 aircraft were eventually built. After the
Lend-Lease programme provided a supply of engines from the United States to Britain, a third variant of the Master, designated
M.27 Master III, was designed, which was powered by the American-built
Pratt & Whitney Twin Wasp Junior, a two-row radial engine that could generate 825 hp (615 kW). A total of 602 Master IIIs were constructed. In a typical trainer configuration, the Master was equipped to carry eight practice bombs, plus a single .303 in
Vickers machine gun that was mounted in the front fuselage. During 1942, it was decided to have the wings of all variants clipped by three feet (c. one metre); this modification reduced the stress imposed upon the wings while also increasing the aircraft's manoeuvrability.
Production A total of 3,249 Masters were built by Phillips and Powis Aircraft Limited (as Miles was known until 1943) at
Woodley, Berkshire;
South Marston, near
Swindon, Wiltshire; and
Doncaster. This was the largest number produced of any Miles aircraft type prior to production of the newer
Miles Martinet taking precedence during 1942. The mass production of this aeroplane at Woodley required a major expansion of the original Phillips & Powis factory, which was officially opened on 27 January 1939 by the
Secretary of State for Air,
Sir Kingsley Wood. This facility was outfitted with a pioneering
moving track assembly line, which is believed to be the first such facility in a British aircraft factory. A similar facility was also installed in the company's shadow factory at South Marston by the end of 1940. ==Design==