Armstrong Whitworth Siskin The Armstrong Whitworth Siskin was a British biplane single - seat fighter aircraft of the 1920s produced by Armstrong Whitworth Aircraft . The Siskin was one of the first new RAF fighters to enter service after the First World War ; it was noted for its aerobatic qualities . Design and development . The design was a development of the Siddeley - Deasy S . R . 2 Siskin , which was designed by Major F . M . Green ( formerly chief engineer of the Royal Aircraft Factory ) of the Siddeley - Deasy Motor Car Company , to meet the requirements of RAF Specification Type 1 for a single - seat fighter powered by the promising ABC Dragonfly radial engine . The SR . 2 Siskin was a single - bay biplane of wood and fabric construction . Its wings were of unequal span and the aircraft was fitted with a distinctive fixed conventional landing gear with long oleo strut shock absorbers carrying the axle , which was connected by radius rod s to a pair of V - struts situated behind the axle . The Dragonfly engine was fitted in a streamlined cowling to reduce drag , with individual cooling channels for each engine cylinder . Two Vickers machine gun s were mounted in the nose decking in front of the pilot . The Siskin first flew in May 1919 , powered by a Dragonfly engine delivering 270 hp ( 200 kW ) , rather than the promised 320 hp ( 240 kW ) . Despite the expectations piled on it , the Dragonfly proved to be a disaster , far less powerful than expected and very unreliable , being prone to overheating and catastrophic vibration , that would normally cause crankshaft failure within a few hours . Despite the engine problems , the Siskin displayed good performance and handling , outmatching its Dragonfly - powered contemporaries . In 1919 , Siddeley - Deasy merged with Armstrong Whitworth , with the aviation interests becoming Armstrong Whitworth Aircraft . Siddeley - Deasly had inherited the design of the RAF . 8 fourteen cylinder radial engine and its designer Sam D Heron , and by 1920 this engine , now known as the Jaguar , had been developed sufficiently to be a possible replacement for the Dragonfly . One of the prototype Siskins was fitted with a Jaguar , flying in this form on 20 March 1921 . In 1922 Air Ministry Specification 14 / 22 was issued for an all - metal single - seat high performance landplane and one Jaguar - powered prototype was ordered from Armstrong Whitworth . As well as re - engining with the Jaguar , Major Green redesigned the Siskin with an all - metal structure , as the Siskin III . A contract for three production aircraft was placed on 13 October 1922 with a further six ordered on 26 January 1923 including one as a prototype of a two - seat variant . The Siskin III first flew on 7 May 1923 , with first deliveries to the RAF ( six for evaluation ) taking place in January 1924 . The fighter was the first all - metal fighter in the British Royal Air Force . Following the order from the RAF , Romania ordered 65 aircraft but they were cancelled following a crash on takeoff at Whitley Abbey , Coventry , on 18 February 1925 during acceptance tests ; the Romanian pilot being killed . The main production version was the Siskin IIIA ordered in 1926 , which originally was powered with a Jaguar IV engine , but was later re - engined with the supercharged Jaguar IVA engine . The supercharger , a novel idea at the time , had little effect on performance below 10 , 000 ft ( 3 , 050 m ) , but it greatly improved speed and climb above that height . Following an evaluation of two Siskin IIIs the Royal Canadian Air Force ordered 12 IIIAs which were delivered between 1926 and 1931 . With Armstrong - Whitworth busy building the Armstrong Whitworth Atlas some of the later Siskin IIIA production was sub - contracted out to Blackburn , Bristol , Gloster and Vickers . Operational history . RAF Service . The first Siskin IIIs were delivered to No . 41 Squadron RAF at RAF Northolt in May 1924 , quickly followed by No . 111 Squadron RAF . The Siskin III was popular in service , being highly manoeuvrable , although slightly underpowered . The improved Siskin IIIA was first delivered to No . 111 Squadron in September 1926 . The Siskin was used by 11 RAF squadrons . The last operational RAF Siskins were replaced in October 1932 by Bristol Bulldog s . The Siskin presented thrilling exhibitions of flying at every RAF display from 1925 to 1931 . Sweden . The ski - equipped second Siskin II aircraft was sold to the Royal Swedish Air Force in 1925 . Canada . Canada used the aircraft from 1926 until 1939 . In 1926 , the British Air Ministry sent two Siskin IIIs to Canada for testing by the Royal Canadian Air Force ( RCAF ) under winter flying conditions . The test pilot was Clennell H . Dickins . The Siskin was considered a modern type when it was introduced into RCAF service , which eventually purchased the Mark IIIA , used to equip the Fighter Flight at Camp Borden and Trenton . In 1937 , the Flight became No . I ( Fighter ) Squadron and was transferred from Trenton to Calgary in August 1938 . Siskin aircraft remained with this unit until the outbreak of the Second World War , eventually to be replaced by Hawker Hurricane s in 1939 . The airframes were then turned over to various technical establishments for use as instructional airframes . Like its RAF counterparts , in 1929 , a three - plane Siskin air demonstration team was formed at Camp Borden , Ontario - the RCAF ' s first official flight demonstration team . The aerobatic team put on popular solo and formation displays from coast to coast . Air racing . The Siskin was used as a successful racing aircraft , a Siskin V flown by Flight Lieutenant Barnard winning the 1925 Kings Cup Race at a speed of more than 151 mph ( 243 km / h ) .