The Bristol Bullpup was a Mercury-powered, single seat, single-bay biplane fighter that was conceived at the same time as the Type 105 Bulldog. It was designed against Specification F.20/27 which sought a fast-climbing interceptor against high-altitude bombing raids.
The Bullpup was in essence, a lightweight scaled-down version of the Bristol Type 105 Bulldog. However, when compared with the Bulldog IIA, the Bullpup was around 700 lb lighter and had a wing area of 230 sq ft (compared to 307 sq ft).
A single example of the Bullpup (J9051) was ordered by the Air Ministry for trials against F.20/27.
The first flight of the Bullpup was made on 28th April 1928 with a Jupiter VI engine installed although a Mercury IIA was subsequently fitted for the Air Ministry trials which started in March 1929. An increase in rudder size was also found necessary after the first flight.
Delays with the Mercury engine prevented further development and the contract ultimately went to the Hawker Fury.
Trials at A & A E E are reported to have shown that the Bullpup could climb to 15,000ft in 10 min 50 sec, compared with 18 min 38 sec for the Bulldog IIA.
Following the trials the Bullpup was also tested with different engine variations such as a short-chord Townend ring cowling and a Jupiter VIIF engine, fitted for the 1930 RAF Display at Hendon. In 1931, a short-stroke Mercury engine was also fitted with a close-fitting NACA-style cowling.
Engine trials continued into 1934 with a 200 hour endurance test of the sleeve-valve Aquila I engine. The Aquila also featured a long-chord, close-fitting cowling and the aircraft was displayed in this form at the SBAC show in June 1935.
Although no production order was ever received, the Bullpup made a real contribution Bristol’s engine development which included tests with a 440hp Jupiter VIIF, a 400hp short-stroke Mercury and a 500hp Aquila I engine.
|Powerplant||480 hp Mercury IIA|
|Span||30 ft 0 in|
|Maximum Weight||2,850 lb|
|Capacity||Single seat, twin synchronised Vickers machine guns. Provision for the carriage of additional underwing guns below the lower wing.|
|Maximum Speed||190 mph (Mercury IIA)|
Single example only, J9051.
Nil; aircraft scrapped in 1935, following completion of Aquila I engine trials.