Bristol Type 138

The Bristol Type 138 was a British single-engined, single-seat, low-wing research monoplane built by the Bristol Aeroplane Company in the 1930s to Air Ministry Specification 2/34, which called for an aircraft able to reach 50,000 feet. Frank Barnwell designed it with a light wooden airframe, a fixed undercarriage and a Bristol Pegasus radial fitted with a two-stage supercharger, and its pilot wore a purpose-built pressure suit and helmet. The Type 138A first flew on 11 May 1936 and took the world altitude record twice for Britain, with 49,967 feet flown by Squadron Leader F. R. D. Swain in September 1936 and 53,937 feet flown by Flight Lieutenant M. J. Adam in June 1937. A second airframe, the Type 138B, was never completed as a flying aircraft.