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Armstrong Whitworth Siskin

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Armstrong Whitworth Aircraft
Company typeAircraft manufacturer
IndustryAerospace
PredecessorSiddeley-Deasy Motor Car Company (aviation division)
Founded1919
Headquarters
United Kingdom
ProductsAircraft (including Armstrong Whitworth Siskin)


Template:Infobox aircraft

The Armstrong Whitworth Siskin was a British single-seat sesquiplane fighter aircraft developed and manufactured by Armstrong Whitworth Aircraft. Notably, it was the first all-metal fighter to be adopted by the Royal Air Force (RAF) and among the earliest new fighters introduced after the conclusion of the First World War.

Its development was largely shaped by RAF Specification Type I, which initially specified the use of the ABC Dragonfly radial engine. The Siskin had its maiden flight in May 1919, demonstrating promising qualities despite the Dragonfly engine's underwhelming performance. Subsequently, in 1921, it was fitted with the more reliable Armstrong Siddeley Jaguar powerplant, with flight tests commencing on 20 March 1921. Following requirements set out in Air Ministry Specification 14/22, the design was revised to feature an all-metal airframe, leading to production orders placed in 1922.

By May 1924, deliveries of the RAF’s Siskin III began, with the first batch assigned to No. 41 Squadron at RAF Northolt. The aircraft served in eleven squadrons overall and earned a favourable reputation among pilots. It remained operational for over eight years until being superseded by Bristol Bulldogs in October 1932. Beyond the RAF, several other countries evaluated and procured the Siskin; notably, the Royal Canadian Air Force (RCAF) introduced it in the late 1920s and continued its use until shortly after the onset of the Second World War. Additionally, some Siskins participated in various air racing competitions.

Origins

The Armstrong Whitworth Siskin evolved from the Siddeley-Deasy S.R.2 Siskin, a design by Major F. M. Green, formerly chief engineer at the Royal Aircraft Factory, working for the Siddeley-Deasy Motor Car Company. A key driver behind its creation was the Air Ministry’s issuance of RAF Specification Type I, which called for a single-seat fighter powered by the ABC Dragonfly radial engine. Unfortunately, this engine proved to be a significant letdown as it failed to achieve its expected performance levels.

The SR.2 Siskin featured a single-bay biplane layout constructed from wood and fabric materials. Its angular design paid little heed to reducing aerodynamic drag. One of its most notable characteristics was its fixed conventional landing gear, equipped with relatively long oleo strut shock absorbers supporting the axle, which was connected via radius rods to V-struts positioned behind it. The wings were of unequal span configuration. The aircraft was powered by an ABC Dragonfly radial engine mounted at the nose within a streamlined cowling that provided individual cooling ducts for each cylinder. Armament comprised two forward-firing Vickers machine guns mounted directly ahead of the pilot.

The prototype took to the air for the first time in May 1919. Although originally fitted with the Dragonfly engine intended to deliver around 320 hp, it only produced approximately 270 hp. Despite early indications of potential, this powerplant suffered from insufficient power output, unreliability, overheating issues, and excessive vibration that led to crankshaft failures after limited operational hours. Nevertheless, even with these engine shortcomings, the Siskin demonstrated favourable handling qualities and stability as well as competitive performance compared to contemporaries competing for RAF contracts.

Redesign

In 1919, Siddeley-Deasy combined forces with Armstrong Whitworth, resulting in the aviation division becoming Armstrong Whitworth Aircraft.[1] Siddeley-Deasy had acquired the design rights to the RAF 8 fourteen-cylinder radial engine along with its creator, Sam D. Heron. By 1920, this engine—renamed the Jaguar—had progressed enough to serve as a replacement for the Dragonfly.[2][3] On 20 March 1921, a prototype Siskin equipped with the Jaguar engine completed its maiden flight.[4] Officials from the Air Ministry expressed approval but recommended Armstrong Whitworth continue refining the aircraft, emphasizing that only a fully metal construction would meet Royal Air Force (RAF) criteria.[5]

In 1922, Air Ministry Specification 14/22 called for an all-metal, single-seat, high-performance landplane. The Siskin was entered and resulted in an order for a single Jaguar-powered prototype.[6] Apart from the engine upgrade, Major Green redesigned it with an all-metal airframe, producing the Siskin III. This all-metal Siskin marked a significant milestone in Britain's shift towards metal construction for military aircraft.[7][8]

Into production

File:Armstrong Whitworth Siskin III RAF.jpg
Armstrong Whitworth Siskin III, J7147, construction no. 31, assigned to No. 41 Squadron on 7 May 1924. It was lost in a flying accident on 9 October 1924.

An initial order for three production aircraft was placed on 13 October 1922, followed by a subsequent contract for six more on 26 January 1923, which included one two-seat model.[9] The Siskin III achieved its first flight on 7 May 1923.[10][11] During thorough testing phases, the ailerons were tapered to prevent jamming incidents experienced during one evaluation flight. Shortly after these modifications, Armstrong Whitworth began manufacturing the production-standard Siskin models, with initial deliveries to the Royal Air Force (RAF) commencing in January 1924[10] for operational trials with No. 41 Squadron. The fighter featured a hybrid wooden and aluminium framework sheathed in doped fabric.

Following RAF procurement, Armstrong Whitworth pursued international sales of the Siskin to bolster company revenues.[12] Romania placed an order for 65 units but later withdrew it after a fatal incident at Whitley Abbey near Coventry on 18 February 1925 when a Romanian pilot perished during takeoff acceptance testing.[13] It is believed that diplomatic pressure from France may have influenced this cancellation.[14]

The principal production model was the Siskin IIIA, initially ordered in 1926,[15] representing the first mass-produced all-metal airframe procured by the RAF.[16] Although originally planned to use the Jaguar IV engine, it was instead outfitted with a supercharged Jaguar IVA powerplant. While the supercharger had minimal impact below 10,000 ft (3,000 m), it significantly enhanced performance in speed and climb rate at higher altitudes.[13] Between 1926 and 1931, the Royal Canadian Air Force acquired twelve IIIA models following evaluation of two earlier Siskin IIIs.Template:CN

Early production runs were completed by Armstrong Whitworth,[17] but due to concurrent demands for the Atlas, some manufacturing of Siskin IIIAs was subcontracted to Blackburn, Bristol, Gloster, and Vickers.[18]

Royal Air Force

File:Siskins of 29.jpg
29 Squadron Siskin formation, late 1920s.

In May 1924, the RAF received its initial batch of Siskin III aircraft, which were assigned to No. 41 Squadron stationed at RAF Northolt.[10] Soon after, No. 111 Squadron also incorporated the type into its fleet, becoming the RAF's pioneer squadron specialized in high-altitude fighter operations.[19] Pilots generally favored the Siskin III for its excellent agility, although it was somewhat lacking in power. Between 1925 and 1931, the aircraft regularly featured in RAF flying exhibitions; a notable demonstration involved three Siskins connected by cords stretched between their interplane struts, requiring precise formation flying to avoid cord breakage until the final maneuver was executed.[20]

The upgraded Siskin IIIA variant began entering service with No. 111 Squadron in September 1926.[21][22] Overall, eleven RAF squadrons operated the Siskin during its tenure. By 1931, the design was becoming outdated, prompting the Air Ministry to deliberate whether to refurbish existing units or acquire newly manufactured fighters as replacements.[23] The final RAF Siskins were retired in October 1932, succeeded by the more advanced Bristol Bulldog.[21]

Sweden

In 1925, the Royal Swedish Air Force acquired the second production Siskin II.[24] This aircraft was outfitted with skis and utilized experimentally for a period.[25]

Canada

File:AW Siskin 2-seater trainer.jpg
RCAF Siskin IIIDC circa 1937 (PAC Photo).

From 1926 through to 1939, Canada maintained a considerable number of Siskins in service. That year, the British Air Ministry sent two Siskin III aircraft for evaluation by the Royal Canadian Air Force (RCAF), where test pilot Clennell H. Dickins assessed their performance under winter conditions.[26] At acquisition, the Siskin was regarded as a contemporary fighter model; consequently, the RCAF procured the Mark IIIA version. The procurement included both newly built units and second-hand aircraft from RAF stocks distributed among several RCAF squadrons.[26]

The Fighter Flight at Camp Borden and Trenton was equipped with Siskins. In 1937, this Flight was redesignated as No. I (Fighter) Squadron and relocated from Trenton to Calgary in August of the following year.[27] RCAF Siskins frequently participated in aerial demonstrations and extensive tours throughout North America.[28]

File:Armstrong-Whitworth Siskin ExCC.jpg
RAF Armstrong-Whitworth Siskin IIIa from No. 41 Squadron at Northolt being serviced with oxygen

The RCAF continued operating the Siskin until shortly after the onset of the Second World War, when it was swiftly phased out and superseded by Hawker Hurricane monoplane fighters.[27] Once withdrawn from active service by the RCAF, these airframes were reassigned to various technical schools for instructional purposes.Template:CN

Mirroring their RAF counterparts, a three-aircraft Siskin aerobatic team was established at Camp Borden in Ontario in 1929—the first official flight demonstration team of the RCAF.[29] This team performed popular solo and formation aerobatics across Canada.[30]

Air racing

The Siskin was a regular contender in air racing competitions, frequently securing victories. Several units competed in the 1924 King's Cup air race, with one aircraft recording the fastest course time despite finishing fourth overall. In the following year's King's Cup, a Siskin V piloted by Flight Lieutenant Barnard claimed first place, reportedly reaching speeds exceeding 151 mph (243 km/h).

Variants

  • Siddeley Deasy S.R.2 Siskin – Initial prototype fighter developed by Siddeley-Deasy, equipped with a Dragonfly engine. A total of three were constructed.
  • Siskin II – Featured a steel-tube fuselage covered with fabric and wooden wings. Two units produced: one single-seater and one two-seater.
  • Siskin III – The all-metal version manufactured for production, with 64 built specifically for the RAF.
  • Siskin IIIA – The principal production model ordered in 1926, totaling 348 aircraft; of these, 340 served with the RAF and eight with the RCAF.
  • Siskin IIIB – A prototype variant fitted with an enhanced engine, converted from a single Siskin IIIA.
  • Siskin IIIDC – Dual-control, two-seat variant; 53 built in total (47 for RAF, two for RCAF, two for AST, and two for Estonia), plus an additional 32 conversions from Siskin IIIs.
  • Siskin IV – A civil racing adaptation, with only one constructed.
  • Siskin V – Single-seat fighter designed for Romania; 65 ordered but only about 10 completed before cancellation. Two were utilized in racing events.

Military operators

File:Canadian Red Ensign (1921–1957).svg Canada
Template:EST
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Civil operators

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Specifications (Siskin IIIA)

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See also

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References

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Citations

  1. ↑ Tapper 1988, p. 18.
  2. ↑ Lumsden 1991, pp. 73–74.
  3. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Tapper p118
  4. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named mason fighter p149
  5. ↑ Tapper 1988, pp. 118-119.
  6. ↑ Meekcoms and Morgan 1994, p. 51.
  7. ↑ Ritchie, 1997, pp.25-26
  8. ↑ Tapper 1988, pp. 119-121.
  9. ↑ Meekcoms and Morgan 1994, p. 66.
  10. ↑ 10.0 10.1 10.2 Mason 1992, p. 164.
  11. ↑ Tapper 1988, p. 123.
  12. ↑ Tapper 1988, pp. 17-18.
  13. ↑ 13.0 13.1 Mason 1992, p. 165.
  14. ↑ Tapper 1988, p. 128.
  15. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  16. ↑ Tapper 1988, p. 141.
  17. ↑ Tapper 1988, p. 124.
  18. ↑ Tapper 1988, pp. 140–141.
  19. ↑ Tapper 1988, p. 129.
  20. ↑ Tapper 1988, p. 132.
  21. ↑ 21.0 21.1 Donald 1997, p. 64.
  22. ↑ Tapper 1988, p. 131.
  23. ↑ Tapper 1988, pp. 133-134.
  24. ↑ Jackson 1973, p. 45.
  25. ↑ Tapper 1988, p. 122.
  26. ↑ 26.0 26.1 Tapper 1988, p. 135.
  27. ↑ 27.0 27.1 Tapper 1988, pp. 136.
  28. ↑ Tapper 1988, pp. 135-136.
  29. ↑ Millberry 1984, p. 45.
  30. ↑ Dempsey 2002, pp. 25–41.

Bibliography

  • Angelucci, Enzo. World Encyclopedia of Military Aircraft. London: Jane's Publishing, 1981. ISBN 0-7106-0148-4
  • Dempsey, Daniel V. A Tradition of Excellence: Canada's Airshow Team Heritage. Victoria, BC: High Flight Enterprises, 2002. ISBN 0968781705
  • Donald, David (ed.). The Encyclopedia of World Aircraft. London: Aerospace Publishing, 1997. ISBN 185605375-X
  • Gerdessen, F. "Estonian Air Power 1918 – 1945". Air Enthusiast, No. 18, April – July 1982. pp. 61–76. Template:ISSN
  • Gunston, Bill. World Encyclopaedia of Aero Engines. Book Club Associates, 1986.
  • Jackson, A.J. British Civil Aircraft since 1919, Volume 1. London: Putnam, 2nd Edition, 1973. ISBN 0370100069
  • Lumsden, Alec. "On Silver Wings — Part 5". Aeroplane Monthly, February 1991, Vol 19 No 2, Issue 214. pp. 72–78. ISSN 0143-7240
  • Mason, Francis K. The British Fighter Since 1912. Annapolis, Maryland: Naval Institute Press, 1992. ISBN 1-55750-082-7
  • Meekcoms, K J and Morgan, E B. The British Aircraft Specification File. Tonbridge, Kent, UK: Air-Britain, 1994. ISBN 0851302203
  • Milberry, Larry. Aviation in Canada. Toronto: McGraw-Hill Ryerson Limited, 1979. ISBN 0070827788
  • Milberry, Larry. 60 Years: The RCAF and CF Air Command 1924–1984. Toronto: Canav Books, 1984. ISBN 0969070349
  • Ritchie, Sebastian. Industry and Air Power The Expansion of British Aircraft Production 1935-1941. Routledge Taylor and Francis Group, 1997. ISBN 0714643432
  • Tapper, Oliver. Armstrong Whitworth Aircraft since 1913. London: Putnam, 1988. ISBN 0851778267.
  • Thetford, Owen. "On Silver Wings — Part 6". Aeroplane Monthly, March 1991, Vol 19 No 3, Issue 215, pp. 138–144. London: IPC. ISSN 0143-7240.

Template:Armstrong Whitworth aircraft Template:Aircraft manufactured in Canada

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