During 1939, Martin-Baker Aircraft designed a new fighter around which was drawn up Specification F.18/39. As with its predecessor the precepts of structural simplicity and sturdiness dominated the design. The fuselage still made use of a patented system of steel tubes, but the skin was stressed light alloy and the wing had a more conventional torsion box structure., Three prototypes were ordered and, designated M.B.3, the first of these was flown on 31 August 1942 with a 2020hp Napier Sabre II 24-cylinder horizontal-H type engine. Armament comprised six 20mm cannon. Only limited handling and performance data had been obtained when, on 12 September 1942, the M.B.3 was destroyed in an accident. Extensive redesign was introduced prior to the completion of the second prototype, which emerged as the M.B.5.

3-View

A three-view drawing (1280 x 930)