Armstrong Whitworth F.K.5
| Industry | Aerospace, Defence |
|---|---|
| Founded | 1914 |
| Founder | William Armstrong, 1st Baron Armstrong |
| Headquarters | Newcastle upon Tyne , England, United Kingdom |
| Products | Aircraft, armaments, engineering products |
The Armstrong Whitworth F.K.5 and F.K.6 were experimental triplane escort fighters developed by Armstrong Whitworth during the First World War. Both models featured twin gunners positioned in nacelles attached to the centre wing. Only one unit of each variant was constructed, and no further production ensued.
Development and design
At the start of 1916, the British War Office issued a specification for a multi-seat escort fighter powered by one of the newly introduced Rolls-Royce Eagle engines. The aircraft was required to sustain at least seven hours of flight endurance to provide protection for bomber formations against German fighters like the Fokker E.I, while also being capable of engaging enemy airships. Prototypes were commissioned from Armstrong Whitworth, Sopwith, and Vickers. Due to the absence of an effective synchronisation gear for firing through the propeller arc, these designs adopted unconventional layouts to ensure gunners had an unobstructed field of fire.[1]
F.K.5
The initial response from Armstrong Whitworth’s chief designer, Frederick Koolhoven, was likely the F.K.5, though definitive records on the exact sequence of Koolhoven’s designations are lacking.[2] It is believed that the escort triplanes bore the designations F.K.5 and F.K.6 and preceded the designs of the F.K.8 and the F.K.9 and F.K.10.[3][4][5] However, some sources refer to these types as F.K.12.[1][6][7]
The F.K.5 was a sizeable single-engine tractor-configured triplane, characterised by a middle wing with a considerably larger span than both the upper and lower wings. Two elongated nacelles mounted atop the middle wing housed the gunners, placing them forward of the propeller disc, while the pilot’s cockpit was positioned behind the wings within a narrow central fuselage that offered limited visibility. The landing gear featured a sprung strut supporting two main wheels beneath the engine, supplemented by stabilising wheels at each lower wingtip and a tailskid located just behind the trailing edge of the lower wing.[8][9] This particular model never achieved flight because I. Fairbairn-Crawford, head of Armstrong Whitworth’s Aircraft division, prohibited any test flying.[10]
F.K.6
Koolhoven undertook a comprehensive redesign resulting in the F.K.6. Although it remained a triplane, the middle wing featured a substantially greater span compared to the upper and lower wings, and the aircraft itself was larger with two-bay wing structures. In this iteration, the gunner's nacelles were suspended beneath the middle wing and were shorter in length, positioning the gunners behind and to the side of the propeller, situated less than 2 ft (0.6 m) from the exhaust manifold. The fuselage was considerably deeper than that of the F.K.5, occupying the space between the middle and lower wings, thereby offering a somewhat improved field of vision. The undercarriage consisted of two pairs of wheels arranged with a narrow track beneath the fuselage, complemented by a more traditional tailskid.
In April 1916, an order was placed for four F.K.6 units, with two designated for the Royal Naval Air Service. However, only one prototype was constructed, which underperformed during evaluation. With the advent of reliable synchronizing gears, development of this model was discontinued, and no escort fighters of this type entered production.
Specifications (F.K.6)
See also
Notes
- ↑ 1.0 1.1 Bruce 1957, p. 25.
- ↑ Tapper 1988, p. 8.
- ↑ Tapper 1988, pp. 72–73.
- ↑ Royal Air Force Museum Aircraft Thesaurus - Armstrong Whitworth Archived 26 July 2011 at the Wayback Machine. Royal Air Force Museum, 2005. Retrieved 19 July 2009.
- ↑ Green and Swanborough 1994, p. 25.
- ↑ Bruce 1965, p. 14.
- ↑ Mason 1992, p. 81.
- ↑ Tapper 1988, pp. 70–71.
- ↑ Bruce 1965, pp. 14, 16.
- ↑ Bruce 1965, p. 16.
References
- Bruce, J. M. British Aeroplanes 1914-18. London: Putnam, 1957.
- Bruce, J. M. War Planes of the First World War: Volume One Fighters. London: Macdonald, 1965.
- Green, William, and Swanborough, Gordon. The Complete Book of Fighters. New York: Smithmark, 1994. ISBN 0-8317-3939-8.
- Lewis, Peter. The British Fighter since 1912. London: Putnam, Fourth edition, 1979. ISBN 0-370-10049-2.
- Mason, Francis K. The British Fighter since 1912. Annapolis, Maryland: Naval Institute Press, 1992. ISBN 1-55750-082-7.
- Tapper, Oliver. Armstrong Whitworth Aircraft since 1914. London: Putnam, 1988. ISBN 0-85177-826-7.
External links
Template:Armstrong Whitworth aircraft Template:Koolhoven aircraft