Armstrong
Whitworth
Siskin

An outstanding fighter design which saw long service with the RAF.
Armstrong Whitworth Siskin III J7664 AW Siskin III J7664 showing the small ventral fin that was deleted on the later Siskin IIIA.
 
The Armstrong Whitworth Siskin, and the history of Armstrong Whitworth aircraft manufacturing after the First World War, is strongly linked to that of the Siddeley-Deasy Motor Car Co Ltd.
 
The origin of Siddeley-Deasy is in what was The Deasy Motor Car Manufacturing Co., formed at Parkside, Coventry in 1906. John Siddeley joined the company in 1910 as Managing Director and it was re-named The Siddeley-Deasy Motor Car Co. Ltd in 1912.  The company then received its first order for aircraft in December 1914 and became one of six companies to produce the Royal Aircraft Factory R.E.8 aircraft from 1916.
 
In 1917, three staff from the Royal Aircraft Factory joined Siddeley-Deasy and began to design fixed-wing aircraft. The main production type was the RE8 (1,030 built, six of which were completed as an improved version, the Siddeley-Deasy RT1). These were followed by a single example of the Siddeley Sinaia (J6858), a twin engine bomber. The Siddeley-Deasy designer John Lloyd next turned his attention to the single seat fighter, with the highly significant Siddeley SR2 Siskin.
 
This was later developed into the Armstrong Whitworth Siskin, following the purchase in 1919, of Siddeley-Deasy by Armstrong Whitworth, with the aircraft subsidiary being named Sir WG Armstrong Whitworth Aircraft Ltd.
 
The Siddeley SR2 Siskin was designed around the powerful new ABC Dragonfly engine. Three were built (C4541 to C4543), the third being the first to fly in May 1919.
 
The AW Siskin was a single bay biplane with unequal span wings, the lower having a smaller chord than the upper. Despite its poor engine, the AW Siskin SR2 showed considerable promise, which came to fruition in the form of the Armstrong Whitworth Siskin III and IIIA, both with the Armstrong Siddeley Jaguar engine.
 
A two seat Armstrong Whitworth Siskin II (G-EBEU) was flown in 1922, followed by a second aircraft in single seat form (G-EBHY) which was exported to Sweden. One Armstrong Whitworth Siskin IV and two Siskin V were also built, these being of mixed construction and flown as civil aircraft.
 
Armstrong Whitworth Siskin IIIA pair on the ground A pair of Armstrong Whitworth Siskin IIIA which was popular with good performance and handling.
 
The all-metal production models were designated Armstrong Whitworth Siskin III and IIIA and featured ‘V’ interplane struts. The chief difference between the III and IIIA models was the installed power and the engine variant used (see specification). The first Armstrong Whitworth Siskin III (J6583) was flown on 7th May 1923, with the first Armstrong Whitworth Siskin IIIA (J8428) following on 21st October 1925.
 
117 Armstrong Whitworth Siskin III were built with 53 as two seat trainers designated Armstrong Whitworth Siskin IIIDC (DC standing for dual control). Thirty-two of the single seat aircraft were converted to the IIIDC configuration. 356 Armstrong Whitworth Siskin IIIA aircraft were built for the RAF.
 
Civil registered Armstrong Whitworth Siskin IIIs (G-EBJQ and G-EBJS) were fitted with long-range tanks and raced in the 1924 King’s Cup Air Race.
 
The first Armstrong Whitworth Siskin III variants were delivered to No. 41 Squadron RAF stationed at RAF Northolt, in May 1924.
 
The Armstrong Whitworth Siskin III was popular in service, being highly manoeuvrable, although slightly underpowered. The improved Armstrong Whitworth Siskin IIIA was first delivered to No. 111 Squadron in September 1926. In total, the Armstrong Whitworth Siskin was used by 11 RAF squadrons, with the last operational aircraft being replaced in October 1932, by Bristol Bulldogs.
 
The Armstrong Whitworth Siskin IIIA was powered by the supercharged Armstrong Siddeley Jaguar IV engine. It featured a reduced dihedral on the upper wing as well as the removal of the small dorsal fin beneath the tail, that had been present on the Armstrong Whitworth Siskin III.
 
Two ex-RAF aircraft were purchased by Royal Canadian Air Force (RCAF) for use in Canada, with 12 others being delivered from RAF stocks.
 
Export orders were received from Romania for 65 Armstrong Whitworth Siskin V aircraft, of which not all were built. Estonia also purchased 2 x two-seat aircraft.
 
Two Siskin V aircraft operated on the UK civil register, taking part in air races (G-EBLN and G-EBLQ).
 
A production total of about 485 Armstrong Whitworth Siskin (including SR2) is quoted, the majority being Armstrong Whitworth Siskin IIIA. Contract production of the Armstrong Whitworth Siskin IIIA was undertaken by Blackburn Aircraft Company (42) Gloster Aircraft Company (74), Bristol Aeroplane Company (84) and Vickers Aviation (42).
 
A Gloster-built Armstrong Whitworth Siskin IIIA J8954. J8954 is a Gloster-built Armstrong Whitworth Siskin IIIA.
 

Specification


 
AW SR2 Siskin
AW Siskin III
AW Siskin IIIA
Powerplant
One 320 hp ABC Dragonfly
One 325 hp Jaguar III
One 420-450 hp Jaguar IV or IVS
Span
27 ft 6 in
33 ft 1 in
33 ft 2 in
All up weight
2,181 lb
2,735 lb
3,012 lb
Capacity & Armament
Single pilot. Twin 0.303 Vickers machine guns.
Single pilot. Twin 0.303 Vickers machine guns.
Single pilot. Twin 0.303 Vickers machine guns. Provision to carry four 20 lb bombs underwing
Maximum Speed
145 mph 6,500 ft
134 mph 6,500 ft, 128 mph at 15,000 ft
156 mph at sea level, 143 mph at 10,000 ft
Endurance
 
3 hr
1.2 hr (full throttle)


Variants and Number built


Siddeley Deasy S.R.2 Siskin
Prototype fighter aircraft built by Siddeley-Deasy and powered by Dragonfly engine. Three built.
Armstrong Whitworth Siskin II
Fabric covered steel-tube fuselage and wooden wings. Two built, one two-seater and one single-seater. G-EBEU, G-EBHY
Armstrong Whitworth Siskin III
All-metal production version (62 built for RAF)
Siskin IIIA
Main production variant ordered in 1926 (Total 348 built, 340 for RAF, eight for RCAF)
Armstrong Whitworth Siskin IIIB
Prototype with improved engine. Single example converted from Armstrong Whitworth Siskin IIIA
Armstrong Whitworth Siskin IIIDC
Two-seat dual control version (Total 53 built, 47 for RAF, two for RCAF, two for AST, two for Estonia) a further 32 were converted from Armstrong Whitworth Siskin IIIs. Two civil aircraft (G-ABHT, G-ABHU)
Armstrong Whitworth Siskin IV
Civil racing version (one built G-EBLL)
Armstrong Whitworth Siskin V
Single-seat fighter for Romania. 65 ordered and at least 10 completed before order cancelled. Two used for racing (G-EBLN, G-EBLQ)
Total built
About 485 (all variants)


Survivors


There are no surviving Armstrong Whitworth Siskin aircraft.