Bristol Bulldog The Bristol Bulldog was a British Royal Air Force single - seat biplane fighter designed during the 1920s by the Bristol Aeroplane Company . Over 400 Bulldogs were produced for the RAF and overseas customers , and it was one of the most famous aircraft used by the RAF during the inter - war period . Background . The design of the Bulldog was the outcome of a series of design studies for fighter undertaken by Frank Barnwell during the 1920 ' s . In 1924 Barnwell had started work on a fighter powered by the Rolls - Royce Falcon to meet the requirements of specification F . 17 / 24 . The project was shelved since Bristol preferred to use their own engine designs , but was revived in 1926 when Barnwell started work on a design , designated the Bristol 102 , to meet either F . 9 / 26 for a day and night fighter or N . 21 / 26 for a shipborne fighter . The Type 105 designation was first applied to a subsequent proposal for another aircraft to meet F . 9 / 26 powered by the Mercury engine then under development at Bristol . These proposals looked promising enough for a pair of mock - ups to be constructed for inspection by the Air Ministry in February 1927 . The two aircraft were similar in design , the interceptor to specification F . 17 / 24 design being slightly smaller and lighter and not equipped with radio . As a result Bristol were asked to revise the design so that it met a later interceptor specification , F . 20 / 27 . Subsequently , a prototype aircraft , now designated the Type 107 Bullpup was ordered for evaluation , but the other design did not gain official backing . Nevertheless Bristol considered it promising enough to build a prototype to be entered for the F . 9 / 26 trials as a private venture , powered by a Bristol Jupiter because the supply of Mercurys was expected to be limited . Design and development . The Type 105 was an unequal span single bay biplane powered by a supercharged Bristol Jupiter VII air - cooled radial engine driving a two - bladed propeller . The structure was all - metal with a fabric covering , using members built up from rolled high - tensile steel strips riveted together . In order to ensure the maximum field of view there was a large semi - circular cutout in the trailing edge of the upper wing and the inboard section of the lower was of reduced chord . Frise aileron s were fitted to the top wing only . It was armed with a pair of 0 . 303 in ( 7 . 7 mm ) Vickers machine guns mounted either side of the cockpit . The prototype Bulldog first flew on 17 May 1927 . Initial testing was entirely satisfactory and it was delivered to RAF Martlesham Heath in June . After initial consideration of all the types entered to meet the specification , the Bulldog and the Hawker Hawfinch were selected for more detailed evaluation . While the Bulldog ' s manoeuvrability and strength were praised by the RAF , it had poor spinning recovery properties . This was solved by fitting an enlarged fin and rudder , but this modification led to difficulties in taxying cross - wind . Accordingly , a second prototype with a lengthened rear fuselage was ordered for further evaluation in comparison with the Hawfinch . In this form , designated the Type 105A or Bulldog Mk . II was first flown by Cyril Uwins on 21 January 1928 and shortly afterward , delivered to Martlesham Heath . Performance was so close to that of the Hawfinch that a decision was deferred until the aircraft had been evaluated by service pilots ; the eventual choice of the Bulldog was made largely because it was easier to maintain . An initial contract for 25 aircraft was placed : Bristol accordingly laid down 26 airframes , the additional example being intended as a company demonstration aircraft . The first of these were delivered on 8 May 1929 and deliveries were complete by 10 October . Later production aircraft were of a refined version designated the Mk . IIA . This had revised wing spars and a stronger fuselage and was powered by the uprated Jupiter VII F . One production aircraft was modified for use as an advanced trainer : after evaluation by the Central Flying School at Upavon this was ordered by the RAF , the production aircraft differing from the prototype in having slightly swept wings and an enlarged fin to improve spin recovery characteristics . Operational history . The Bulldog never saw combat with the RAF , although during the Abyssinia Crisis of 1935 – 36 , Bristol Bulldogs were sent to the Sudan to reinforce Middle East Command . Douglas Bader , better known for his Second World War actions , lost both of his legs when his Bristol Bulldog crashed while he was performing unauthorised Aerobatics at Woodley airfield near Reading . The Bulldog was withdrawn from RAF Fighter Command in July 1937 , being primarily replaced by the Gloster Gauntlet . The Bulldog ' s RAF career was not over though , for the type continued to serve for a few years with Service Flying Training Schools . The Bulldog proved to be quite a successful export to foreign air forces , seeing service with Australia , Denmark , Estonia , Finland , Japan , Latvia , Siam and Sweden . In 1936 , Latvia , keen to replace its elderly Bulldogs with more modern aircraft , sold 11 Bulldogs to Basque nationalist forces ; becoming part of the Spanish Republican Air Force in the Spanish Civil War , they remained in use until the Battle of Santander . Nineteen Bulldogs also saw combat as part of the Finnish Air Force during the Winter War against the Soviet Union , which began in 1939 . The Bulldogs fought well against their Soviet opponent , gaining six kills by five pilots for the loss of one of their own , the types shot down being two Polikarpov I - 16 s and four Tupolev SB s , both of which were superior in terms of technology compared to the Bulldog . The first aerial victory of the Finnish Air Force was achieved by a Bulldog piloted by SSgt Toivo Uuttu on 1 December 1939 , over an I - 16 . The Bulldogs were used in advanced training during the subsequent Continuation War against the Soviet Union . Survivors . A Bulldog ( S . No . Unknown ) survives at the RAF Museum , Hendon . A Bulldog IV ( S . No . Unknown ) survives at the Hallinportti Aviation Museum , Kuorevesi , Jämsä , Finland .