| F.K.8 | |
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| Un-numbered experimental F.K.8 with small radiators, streamlined nose, and vee-undercarriage.[1] [2]. | |
| Role | Bomber/Reconnaissance aircraft |
| Manufacturer | Armstrong Whitworth |
| Designed by | Frederick Koolhoven |
| First flight | May 1916 |
| Primary users | Royal Flying Corps Qantas |
| Developed from | Armstrong Whitworth F.K.7 |
The Armstrong Whitworth F.K.8 was a British two-seat general-purpose biplane built by Armstrong Whitworth during the First World War.
Contents |
Design and development
The aircraft, originally designated the F.K.7, was designed by Dutch aircraft designer Frederick Koolhoven as a replacement for the Royal Aircraft Factory B.E.2c and the Armstrong Whitworth F.K.3.
The F.K.7 was a sturdier aircraft than the F.K.3, with a larger fuselage and wings and was powered by a 160 hp (110 kW) Beardmore water-cooled engine.[3] The undercarriage used oleo shock absorbers and the observer was equipped with a Scarff ring mounting for a .303 in (7.7 mm) Lewis machine gun. No armament was provided for the pilot. The rudder featured a long, pointed horn-balance.[3]
The type was unusual in having dual controls, enabling the observer to control the aircraft in the event of the pilot becoming incapacitated by enemy action.[4]
The first F.K.7, A411, flew in May 1916 and was delivered to the Royal Flying Corps' Central Flying School at Upavon on 16 June.[3] Because its main rival, the Royal Aircraft Factory R.E.8 was still an unknown quantity, it was decided that 50 of the Armstrong Whitworth design, which was redesignated F.K.8., would be ordered for the RFC.[3]
The production aircraft which followed were identical in most repects to A411, with the addition of a forward-firing .303 in (7.7 mm) Vickers machine gun to port of and slightly behind the engine. The Armstrong Whitworth gun synchronising mechanism was still incomplete at the time the first example A2636 had arrived in France and some early production F.K.8s may have used the Arsiad interrupter gear instead. In the event, the Armstrong Whitworth mechanism proved unreliable and was later replaced by the Constantinescu gear.[5] From the fifth production aircraft the rudder balance was shortened and the shape of the vertical tailfin was modified.[6]
Initially, the F.K.8s suffered from operational problems; the oleo undercarriage was unable to withstand rough usage on the frontline airfields, tailskids frequently broke and the original radiators blocked up quickly.[5] Following instructions issued on 30 April 1917, some F.K.8s were refitted with simplified vee-undercarriages from Bristol F.2 Fighters. This soon led to a temporary shortage of these undercarriages, and the practice had to be discontinued until May 1918, after which time several F.K.8s were fitted with the units.[7] Most production F.K.8s introduced modifications to the wings, gunner's seat and the exhaust system, and the tall, inverted vee radiators incorporated improved tubes which reduced the blockages. On later aircraft the nose cowling was redesigned.[8]
In service the F.K.8s (nicknamed the "Big Ack") proved to be effective and dependable, being used in such diverse roles as reconnaissance, artillery spotting, ground-attack, contact-patrol and day and night bombing.[2] It was easier to fly than the R.E.8, and was sturdier, but its performance was even more pedestrian, and it shared the inherent stability of the Royal Aircraft Factory types.
The F.K.13 seems to have been the designation of a reconnaissance version of the F.K.8, but it may well have been just a project.[9]
A total of 1,650 were built, and the type served alongside the R.E.8 until the end of the war, at which point 694 F.K.8s remained on RAF charge.
Operational history
The F.K.8 served with several squadrons on operations in France, Macedonia, Palestine and for home defence, proving more popular in service than its better known contemporary, the R.E.8. The first squadron was 35 Squadron. The F.K.8 was principally used for the corps reconnaissance role, but was also used for light bombing, being capable of carrying up to six 40 lb (20 kg) phosphorus smoke bombs, up to four 65 lb (29 kg) bombs or two 112 lb (51 kg) bombs on underwing racks.[10]
Two Victoria Crosses were won by pilots of F.K.8s; one by Second Lieutenant Alan Arnett McLeod of No. 2 Squadron RFC, on 27 March 1918;[10] and the second by Captain Ferdinand Maurice Felix West of No. 8 Squadron RAF on 10 August 1918.[11]
With the R.E.8, the F.K.8 was scheduled to be replaced in the corps reconnaissance role by a version of the Bristol Fighter with a Sunbeam Arab engine. Unfortunately the engine was unsatisfactory, and this version of the Bristol never saw service. Like the R.E.8, the F.K.8 was quickly discarded with the end of the war – the last squadron, No. 150 Squadron RAF, being disbanded at Kirec in Greece on 18 September 1919.[11]
One F.K.8 was purchased by a pilot named Sydney Stewart in the early 1920s. He took the aircraft to Buenos Aires and gave flying lessons. There he met Francisco Cusmanich, a Paraguayan pilot. Stewart and Cusmanich offered their services to the Paraguayan government during the Revolution of 1922. The F.K.8 was taken to Paraguay by ship. It received the name of "Presidente Ayala" in honor of the President of Paraguay at that time, Dr. Eusebio Ayala. Both pilots flew several reconnaissance and light bombing mission over the rebel positions. In one of those missions, the F.K.8 was hit several times with ground fire causing an explosion on board, killing both Stewart and Cusmanich instantly.[12][13]
Civil service
Eight aircraft were civil-registered after the war with two aircraft being used in Australia by the Queensland and Northern Territory Aerial Services (later QANTAS, then Qantas Airways Ltd.).[14]
Operators
Civil operators
Military operators
- Royal Flying Corps / Royal Air Force (From 1 April 1918)
Western Front:[15]
-
- 2 Squadron RFC
- 8 Squadron RFC
- 10 Squadron RFC
- 35 Squadron RFC
- 82 Squadron RFC
- Headquarters Communication Squadron RFC
Home Defence:[15]
Macedonia:[15]
-
- 17 Squadron RFC (part)
- 47 Squadron RFC (part)
Palestine:[15]
-
- 142 Squadron RFC
Training:[16]
-
- 3 Training Squadron RFC
- 15 Training Squadron RFC
- 31 Training Squadron RFC
- 39 Training Squadron RFC
- 50 Training Squadron RFC
- 57 Training Squadron RFC
- 61 Training Squadron RFC
- 110 Training Squadron RFC
- 127 Training Squadron RFC
- 1 Training Depot Station RFC
- Paraguayan Government
Specifications (F.K.8)
Data from The Encyclopedia of World Aircraft[17]
General characteristics
- Crew: 2
- Length: 31 ft 5 in (9.58 m)
- Wingspan: 43 ft 6 in (13.26 m)
- Height: 10 ft 11 in (3.33 m)
- Wing area: 540 ft² (50.17 m²)
- Empty weight: 1,916 lb (869 kg)
- Max takeoff weight: 2,811 lb (1,275 kg)
- Powerplant: 1× Beardmore 120 hp 6-cylinder inline piston engine, 160 hp (112 kW)
Performance
- Maximum speed: 83 kn (95 mph, 153 km/h) at sea level
- Service ceiling: 13,000 ft (3,960 m)
- Endurance: 3 hours
Armament
- Guns: 1 × fixed, forward firing .303 in Vickers machine gun and 1 × flexibly mounted .303 in Lewis gun[11]
- Bombs: up to 260 lb (118 kg) bombs[11]
See also
Related development
Comparable aircraft
References
- Notes
- ^ Note: The un-numbered experimental F.K.8 was the property of the Armstrong Whitworth company. This aircraft had a company designed undercarriage, long exhaust pipe and small, nose mounted radiators. It was evaluated by 2 Squadron RFC, who reported favourably on the modifications. However, these modifications were not carried into production.
- ^ a b Bruce 1982, p. 104.
- ^ a b c d Bruce 1982, pp.100-101.
- ^ Munson 1967, p. 31.
- ^ a b Bruce 1982, p. 101.
- ^ Bruce 1982, p. 102.
- ^ Bruce 1982, pp. 102–103.
- ^ Bruce 1982, p. 103.
- ^ Bruce, J. M. "Letter from J.M.Bruce to Flight, 15 May 1953, p. 612." flightglobal.com, 15 May 1953. Retrieved: 7 December 2009.
- ^ a b Mason 1994, p. 63.
- ^ a b c d Mason 1994, p. 64.
- ^ Klaus, Erich. "Paraguay Air Force." Aeroflight, 2 October 2008. Retrieved: 23 April 2009.
- ^ English, Adrian J. ""La Guerra Civil Parguaya 1922-1923." Historia y Arqueologia Marítima. Retrieved: 23 April 2009.
- ^ Tapper 1988, pp. 67–68.
- ^ a b c d Bruce 1982, pp. 103, 105.
- ^ Bruce 1982, p.104.
- ^ Donald, David and Jon Lake, eds. The Encyclopedia of World Aircraft. London: Blitz, 1997. ISBN 1-85605-375-X.
- Bibliography
- Bruce, J.M. "The Aeroplanes of the Royal Flying Corps (Military Wing)." London: Putnam and Company, 1982. ISBN 0-370-30084-X.
- Mason, Francis K. The British Bomber Since 1914. London: Putnam Aeronautical Books, 1994. ISBN 0-85177-861-5.
- Munson, Kenneth. Aircraft of World War I. London: Ian Allan, 1967. ISBN 0-7110-0356-4.
- Tapper, Oliver. Armstrong Whitworth Aircraft since 1913. London: Putnam, 1988. ISBN 0-85177-826-7.
- Taylor, John W.R. "Armstrong Whitworth F.K.8." Combat Aircraft of the World from 1909 to the present. New York: G.P. Putnam's Sons, 1969. ISBN 0-425-03633-2.
External links
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