02/28/2008. Remarks by Johan Visschedijk: "The British Air Ministry ordered a special high-altitude research aircraft to be built by Bristol according Specification 2/34, this became the Bristol 138A. It was powered by a specially designed 500 hp Bristol Pegasus P.E.6S nine-cylinder radial piston engine fitted with two superchargers, the second of which came in use above about 35,000 ft (10,668 m). The aircraft had a fixed landing gear and was equipped with a heated enclosed cockpit. It first flew on May 11, 1936.

Wearing an oxygen helmet and a pressure suit Squadron Leader F.R.D. Swain piloted the aircraft to a record height of 49,944 ft (15,223 m), on September 28, 1936, it took about 90 minutes to reach this height. An Italian Caproni 161 broke the record on May 5, 1937, when it climbed to 51,394 ft (15,655 m). The British aircraft was lightened by removing the brakes and fitting of smaller wheels, and on June 30, 1937, the record was regained when Flight Lieutenant M.J. Adam reached 53,937 ft (16,440 m). On October 22, 1938 the improved Caproni 161bis reached 56,046 ft (17,083 m), this time Britain made no attempt to regain the record."