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Bristol 107
Bullpup

A single-seat interceptor fighter prototype that did not enter production, but was subsequently used for engine testing.
Bristol 107 Bullpup Jaguar VI prior to first flight The Bristol Bullpup at Filton in April 1928 with Jupiter VI and initial small rudder.
 
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).
 
Bristol 107 Bullpup J9051 Bristol 107 Bullpup J9051 with Mercury IIA and metal wing struts, as tested ar Martlesham Heath.
 
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.
 
Bristol 107 Bullpup Townend Ring Mercury IIA The Bristol Bullpup with Mercury IIA engine and narrow-chord Townend ring cowling.
 
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.
 
Bristol 107 Bullpup Aquila I The Bullpup in its final form with AquilaI engine, as displayed 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.

Specification

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) 

Variants

Single example only, J9051.

Survivors

Nil; aircraft scrapped in 1935, following completion of Aquila I engine trials.

Other information