Армастронг Уитворт Сискин: Первый всеметаллический истребитель Королевских ВВС

The Armstrong Whitworth Siskin was a sesquiplane single seat fighter aircraft developed and produced by the British aircraft manufacturer Armstrong Whitworth Aircraft. It was also the first all metal fighter to be operated by the Royal Air Force (RAF), as well as being one of the first new fighters to enter service following the end of the First World War. Development of the Siskin was heavily influenced by RAF Specification Type I, including its initial use of the ABC Dragonfly radial engine. Making its first flight in May 1919, the Siskin possessed good qualities in spite of the Dragonfly's poor performance. In the following year, the much better Armstrong Siddeley Jaguar was installed and flight with this powerplant was made on 20 March 1921. In response to Air Ministry Specification 14/22, the aircraft was redesigned with an all metal structure, and orders were placed in 1922. In May 1924, the first of the RAF's Siskin IIIs were delivered to No. 41 Squadron at RAF Northolt. Eleven squadrons would operate the type. Relatively popular with pilots, it served for over eight years before the last of them were replaced by Bristol Bulldogs during October 1932. In addition to the RAF, various other nations evaluated the Siskin and several placed orders. The Royal Canadian Air Force (RCAF) introduced the type in the late 1920s and operated its Siskins until shortly after the outbreak of the Second World War. Several Siskins were also entered in various air races.

The Armstrong Whitworth Siskin was a development of the Siddeley Deasy S. R.2 Siskin designed by Major F. M. Green (formerly chief engineer of the Royal Aircraft Factory) of the Siddeley Deasy Motor Car Company. The SR.2 Siskin was a single bay biplane of wood and fabric construction. It angular in form, with little attention paid to obvious avenues for drag reduction. Despite early promise, the Dragonfly was disastrous, being less powerful, unreliable, and prone to overheating while excessive vibration resulted in crankshaft failures after only a few hours of use. Despite the engine, the Siskin displayed generally good properties, possessing favourable stability and handling characteristics, along with performance that could outmatch its direct rivals for RAF orders. Siddeley Deasy had inherited the design of the RAF 8 fourteen cylinder radial engine and its designer Sam D. Heron. By 1920, this engine, as the Jaguar, had been developed sufficiently to replace the Dragonfly. During 1922, Air Ministry Specification 14/22 was issued for an all metal single seat high performance landplane. The Siskin was submitted leading to an order for a single Jaguar powered prototype. Aside from the engine change, Major Green redesigned it with an all metal structure, as the Siskin III. The all metal Siskin was the start of the British transition to metal for military aircraft.

On 13 October 1922, an initial contract for three production aircraft was placed, and a follow on order for a further six followed on 26 January 1923, including a single two seat variant. The Siskin III made its first flight on 7 May 1923. A comprehensive evaluation was conducted, during which the ailerons were tapered to prevent them jamming, as happened during one test flight. Shortly thereafter, Armstrong Whitworth commenced construction of the production standard Siskin, the first of which were delivered to the Royal Air Force (RAF) in January 1924 Romania ordered 65 aircraft, but cancelled the order following a fatal accident at Whitley Abbey, Coventry on 18 February 1925 when a Romanian pilot died in a crash on take off, during acceptance tests. Political pressure by France may have also contributed to the order's cancellation however. The Siskin IIIA was the main production version, which was first ordered during 1926, and was the first all metal framed aircraft to be procured in quantity for the RAF. This variant was to have been powered with a Jaguar IV, but was given a supercharged Jaguar IVA engine instead. The supercharger had little effect on performance below 3048.00 m, but greatly improved speed and climb above that height. due to production demands for the Atlas, some Siskin IIIA production was subcontracted out to Blackburn, Bristol, Gloster, and Vickers.

During May 1924, the RAF's first Siskin IIIs were delivered to No. 41 Squadron at RAF Northolt. The Siskin III was relatively popular amongst its pilots, being a highly manoeuvrable aircraft, although slightly underpowered. Between 1925 and 1931, Siskins were frequently presented at RAF exhibitions of flying; one particular feat performed was the linking of three aircraft by cords between their interplane struts, necessitating careful formation flying to not break these cords until the finishing manoeuvre was performed. During September 1926, the first deliveries of the improved Siskin IIIA variant were made to No. 111 Squadron. In total, the Siskin was operated by eleven RAF squadrons. By 1931, the type was showing its age, leading to the Air Ministry considering either to recondition them or to procure new built fighters to replace them. During October 1932, the final Siskins in RAF service were withdrawn, the type having been replaced by the newer and more capable Bristol Bulldog. It was equipped with skis and flown in an experimental capacity for a time.

Between 1926 and 1939, Canada operated a sizable fleet of Siskins. During 1926, the British Air Ministry had dispatched a pair of Siskin IIIs to Canada, where they underwent testing by the Royal Canadian Air Force (RCAF) under winter flying conditions by test pilot Clennell H. Dickins. The Siskin was considered a modern type at the time of its acquisition by the RCAF, which opted to purchase the Mark IIIA. The Canadian procurement involved both new built aircraft and second hand RAF Siskins being supplied to numerous RCAF squadrons. The unit continued to operate the Siskin up until the outbreak of the Second World War, shortly after which the type was rapidly retired and replaced by Hawker Hurricane monoplane fighters. Following the Siskin's withdrawal by the RCAF, the airframes were 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.

The Siskin frequently participated in air racing, often triumphing in such events. Multiple examples were entered into the 1924 King's Cup air race, one of which achieving the fastest course time despite arriving fourth. In the 1925 King's Cup, a Siskin V flown by Flight Lieutenant Barnard emerged as the winner, having reportedly achieved a speed in excess of .