Miles M.20

The Miles M.20 was a Second World War fighter developed by Miles Aircraft in 1940. Designed as a simple and quick-to-build 'emergency fighter' alternative to the Royal Air Force's Spitfires and Hurricanes should their production get disrupted by bombing. In the event, due to dispersal of manufacturing, the Luftwaffe's bombing of the Spitfire and Hurricane factories did not seriously affect production, and so the M.20 proved unnecessary and was cancelled.

Design and development
During the Battle of Britain, the Royal Air Force was faced with a potential shortage of fighters. To meet the Luftwaffe threat, the Air Ministry commissioned Miles to design the M.20, to specification F.19/40; nine weeks and two days later the first prototype flew.

To reduce production times the M.20 was of an all-wood construction, used many parts from the earlier Miles Master trainer, lacked hydraulics, and had spatted fixed landing gear. The engine was a complete Rolls-Royce Merlin XX "power egg", and was identical to those used on the Avro Lancaster and some Bristol Beaufighter marks. The design also featured a bubble canopy for improved pilot visibility, one of the first fighters to do so.

Testing and evaluation
The first prototype, with the B-class serial U-9 first flew on 15 September 1940, and was tested at the A & AEE under the military serial number AX834 against Specification F.19/40. Armed with the same eight .303 Browning machine guns as the Hawker Hurricane, the M.20 prototype was faster than the Hurricane and slower than the Spitfire types then in production, but carried more ammunition and had greater range than either. As the Luftwaffe was defeated over Britain, the need for the M.20 vanished and the design was abandoned without entering production. The first prototype was later scrapped at Woodley.

A second prototype, U-0228 and later serialed as DR616, was built to Specification N.1/41 for a Fleet Air Arm shipboard fighter, equipped with an arrestor hook and catapult launch points. It first flew on 8 April 1941. This variant was also fitted with jettisonable undercarriage so it could be used from catapults on Catapult Aircraft Merchantmen, however these ships had no flight decks so the aircraft had to be ditched into the sea after just one mission. Old Hawker Hurricanes took on this role, relegating the M.20 as superfluous and consequently leading to the scrapping of the shipboard variant.