| Siskin | |
|---|---|
 "The Siskins" flight demonstration team | |
| General information | |
| Type | Fighter |
| Manufacturer | Sir W.G. Armstrong Whitworth Aircraft Limited |
| Designer | F.M. Green |
| Primary users | Royal Air Force |
| Number built | 485[1] |
| History | |
| Introduction date | 1923 |
| First flight | May 1919 asSiddeley-Deasy S.R.2 Siskin[2] |
| Retired | 1932 |
| Variant | Armstrong Whitworth Starling |
TheArmstrong Whitworth Siskin was asesquiplane single-seatfighter aircraft developed and produced by the British aircraft manufacturerArmstrong Whitworth Aircraft. It was also the first all-metal fighter to be operated by theRoyal Air Force (RAF), as well as being one of the first new fighters to enter service following the end of theFirst World War.
Development of the Siskin was heavily influenced byRAF Specification Type I, including its initial use of theABC Dragonflyradial 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 betterArmstrong Siddeley Jaguar was installed and flight with this powerplant was made on 20 March 1921. In response toAir 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 toNo. 41 Squadron atRAF Northolt. Eleven squadrons would operate the type. Relatively popular with pilots, it served for over eight years before the last of them were replaced byBristol Bulldogs during October 1932. In addition to the RAF, various other nations evaluated the Siskin and several placed orders. TheRoyal Canadian Air Force (RCAF) introduced the type in the late 1920s and operated its Siskins until shortly after the outbreak of theSecond World War. Several Siskins were also entered in variousair races.
The Armstrong Whitworth Siskin was a development of the Siddeley-Deasy S.R.2 Siskin designed by MajorF. M. Green (formerly chief engineer of theRoyal Aircraft Factory) of theSiddeley-Deasy Motor Car Company.[3] A major impetus for the aircraft's development was theAir Ministry's issuing ofRAF Specification Type I, which called for a single-seat fighter that was powered by theABC Dragonflyradial engine. The Dragonfly would prove to be a disappointment as it failed to meet its anticipated performance.[3][4]
The SR.2 Siskin was a single-baybiplane of wood and fabric construction. It was angular in form, with little attention paid to obvious avenues fordrag reduction.[5] Perhaps its most distinctive feature was its fixedconventional landing gear, which had relatively lengthyoleo strutshock absorbers carrying theaxle, which was in turn connected byradius rods to a pair of V-struts situated behind the axle. Its wings were of unequal span. It was powered by a singleABC Dragonflyradial engine, which was installed on the nose in astreamlinedcowling. To regulate the engine's temperature, each individualcylinder had its own cooling channel. Armament consisted of a pair ofVickers machine guns mounted directly in front of the pilot.[2][6]
The Siskin made its first flight in May 1919.[6] While the initial aircraft was powered by the intended Dragonfly engine, it would only deliver 270 hp (200 kW) rather than the expected 320 hp (240 kW).[2] Despite early promise, the Dragonfly was disastrous, being less powerful, unreliable, and prone to overheating while excessive vibration resulted incrankshaft failures after only a few hours of use.[7] 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.[8][6]
In 1919, Siddeley-Deasy merged withArmstrong Whitworth, with the aviation interests becomingArmstrong Whitworth Aircraft.[9] Siddeley-Deasy had inherited the design of the RAF 8 fourteen-cylinder radial engine and its designerSam D. Heron. By 1920, this engine, as theJaguar, had been developed sufficiently to replace the Dragonfly.[10][6] A prototype Siskin fitted with a Jaguar flew on 20 March 1921.[2] Air Ministry officials were impressed but urged Armstrong Whitworth to continue developing the aircraft as only an all-metal design would be acceptable to theRoyal Air Force (RAF).[11]
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.[12] Aside from the engine change, Major Green redesigned it with an all-metal structure, as theSiskin III. The all-metal Siskin was the start of the British transition to metal for military aircraft.[13][14]
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.[15] The Siskin III made its first flight on 7 May 1923.[16][5] A comprehensive evaluation was conducted, during which theailerons weretapered 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 theRoyal Air Force (RAF) in January 1924[16] for flight trials onNo. 41 Squadron. The fighter was constructed with a composite wood and aluminium frame, covered in doped linen fabric.
Following the orders from the RAF, Armstrong Whitworth worked on securing export sales for the Siskin. Siskin sales played a major role in the company's fortunes for a time.[17]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.[18] Political pressure by France may have also contributed to the order's cancellation however.[19]
The Siskin IIIA was the main production version, which was first ordered during 1926,[20] and was the first all-metal framed aircraft to be procured in quantity for the RAF.[21] This variant was to have been powered with a Jaguar IV, but was given asupercharged Jaguar IVA engine instead. The supercharger had little effect on performance below 10,000 ft (3,000 m), but greatly improved speed and climb above that height.[18] TheRoyal Canadian Air Force received 12 IIIAs between 1926 and 1931 after evaluating two Siskin IIIs.[citation needed]
Early production examples were built by Armstrong Whitworth but[22] due to production demands for theAtlas, some Siskin IIIA production wassubcontracted out toBlackburn,Bristol,Gloster, andVickers.[23]
During May 1924, the RAF's first Siskin IIIs were delivered toNo. 41 Squadron atRAF Northolt.[16] Shortly thereafter,No. 111 Squadron also received the model; its adoption enabled No. 111 to become the RAF's first high-altitude fighter squadron.[24] 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.[25]
During September 1926, the first deliveries of the improved Siskin IIIA variant were made to No. 111 Squadron.[26][27] 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.[28] During October 1932, the final Siskins in RAF service were withdrawn, the type having been replaced by the newer and more capableBristol Bulldog.[26]
The second Siskin II aircraft was sold to theRoyal Swedish Air Force in 1925.[29] It was equipped with skis and flown in an experimental capacity for a time.[30]
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 theRoyal Canadian Air Force (RCAF) under winter flying conditions by test pilotClennell H. Dickins.[31] 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.[31]
The Siskin equipped the Fighter Flight atCamp Borden andTrenton. During 1937, the Flight became No. I (Fighter) Squadron, and was transferred from Trenton toCalgary in August 1938.[32] RCAF Siskins were also frequently used in aerial displays and long distance tours around North America.[33]
The unit continued to operate the Siskin up until the outbreak of theSecond World War, shortly after which the type was rapidly retired and replaced byHawker Hurricanemonoplane fighters.[32] Following the Siskin's withdrawal by the RCAF, the airframes were turned over to various technical establishments for use as instructional airframes.[citation needed]
Like its RAF counterparts, in 1929, a three-planeSiskin air demonstration team was formed at Camp Borden, Ontario – the RCAF's first official flight demonstration team.[34] The aerobatic team put on popular solo and formation displays from coast to coast.[35]
The Siskin frequently participated inair racing, often triumphing in such events. Multiple examples were entered into the 1924King's Cup air race, one of which achieving the fastest course time despite arriving fourth.[36] In the 1925 King's Cup, a Siskin V flown byFlight Lieutenant Barnard emerged as the winner, having reportedly achieved a speed in excess of 151 mph (243 km/h).[37]
Data fromThe British Fighter since 1912[45]
General characteristics
Performance
Armament
Aircraft of comparable role, configuration, and era
Related lists
