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. Development Background 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. A major impetus for the aircraft's development was the Air Ministry's issuing of RAF Specification Type I, which called for a single-seat fighter that was powered by the ABC Dragonfly radial engine. The Dragonfly would prove to be a disappointment as it failed to meet its anticipated performance. 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. Perhaps its most distinctive feature was its fixed conventional landing gear, which had relatively lengthy oleo strut shock absorbers carrying the axle, which was in turn connected by radius rods to a pair of V-struts situated behind the axle. Its wings were of unequal span. It was powered by a