Gloster F.5/34

The Gloster F.5/34 was a British fighter of the 1930s. It was a single-seat, single-engine monoplane of all-metal cantilever construction; the undercarriage was of the tailwheel type with retractable main units.

Role fighter
Manufacturer Gloster Aircraft
Designer Henry Folland and H.E. Preston
First flight December 1936
Retired 1941
Status Abandoned project
Number built 2

It was developed for Air Ministry Specification F.5/34, a fighter armed with eight machine guns and an air-cooled engine that was well-suited to operations in the tropics.[1] Gloster's design was overtaken by more capable competitors and the Specification was later abandoned, with no aircraft being selected.

Design and development

The F.5/34 was the first monoplane fighter built by Gloster and the last design by H.P. Folland for the company.[2] It was also Gloster's first monoplane that was not a seaplane.

The first design was based on a low-wing monoplane version of the Gladiator, probably retaining the fabric covering, and with the vertical fin and full-height rudder behind the tailplane, as for the Gladiator. The engine was to be the new Bristol Perseus sleeve-valve radial. The cockpit was semi-enclosed, with open sides and a spine behind it. The undercarriage retracted backwards and left the wheels half-exposed, which would reduce damage in the event of a wheels-up landing.[3]

By 1935, the design had changed and had acquired a number of more modern features such as a metal stressed-skin fuselage throughout. The cockpit canopy was now a glazed and framed canopy like that of the production Gladiator which slid backwards to open, giving much better vision above and behind. Although the main dimensions remained unchanged, the tailplane moved backwards behind the fin, requiring an extension of the fuselage beyond it and increasing the overall length by 3 feet. This was an innovation developed for the F.35/35 high-speed fighter specification. The intention was to improve spin recovery, by having the fin and rudder in 'clean' air, ahead of the tailplane.[3]

The engine also changed, at least for the prototype aircraft, to the older Bristol Mercury poppet-valve engine.[3] The Perseus had been developed with identical cylinder dimensions to the Mercury and was only a little larger, making the change an easy one. The Perseus was still under development and although it was likely that the sleeve valve would, and later did, give much greater scope for development, the Mercury was acceptable for development of the prototype airframe with the Perseus restored later.[4]

Powered by an 840 hp Bristol Mercury IX nine-cylinder radial engine, the F.5/34, was informally called the Unnamed Fighter, featured many of the trademark Gloster design elements including the tail and close-fitting cowling that resembled the earlier Gauntlet and Gladiator biplane fighters.[2] The low wing cantilever mainplane was built in one piece with light-alloy spars running through from tip to tip and ribs made from channelling with steel and light-alloy tube struts. NACA 2218 profiles were used at the root and NACA 2209 at the tip. The single piece wing was later criticised as it would have prevented battle damage being repaired by replacing a single wing.[3] Duralumin stressed-skin was used on the mainplane and tail unit with fabric-covered Frise ailerons. The fuselage was a monocoque structure built up from light, fabricated oval-section rings with duralumin skinning.[5]

Unlike the usual practice and the single prototypes ordered for the Spitfire and Hurricane, a pair were ordered. Development was delayed by the demands of the Gladiator production programme, so that flight trials of the first prototype K5604 did not commence until December 1936. The second prototype K8089 did not fly until March 1938.[3]


In competition with the Gloster for the requirement were the Bristol Type 146, Martin-Baker M.B.2 and the Vickers Venom, which would be tested by the Aeroplane and Armament Experimental Establishment. Flight magazine (1 July 1937) shows the F.5/34 taking off from Hucclecote Aerodrome and mentions its appearance at the RAF Display of that year.[6] By the time the F.5/34 began its flight tests, the eight-gun Hawker Hurricane was in service and the Supermarine Spitfire in production so that further development of the Gloster fighter was abandoned. Compared to its contemporaries, test pilots found the F.5/34 prototypes had a shorter take off run, offered better initial climb and were more responsive and manoeuvrable due to ailerons that did not become excessively heavy at high speed. Handling was considered very good and the all-round cockpit visibility was far better than the other designs. The Gloster F.5/34 debuted at the 1937 Hendon Air Show but soon after, prototypes K5604 and K8089 were relegated to experimental flying and finally as instructional airframes until May 1941.[7] A belief exists that the F.5/34 was the inspiration for the Japanese Zero, probably stemming from a superficial similarity between the two machines and Gloster's past links with the Japanese such as the Nakajima A1N, a licensed development of Gloster Gambet.[8]

Specifications (F.5/34)

Data from The Complete Book of Fighters[9]

General characteristics

  • Crew: 1
  • Length: 32 ft (9.76 m)
  • Wingspan: 38 ft 2 in (11.63 m)
  • Height: 10 ft 2 in (3.09 m)
  • Wing area: 230 ft2 (21.4 m2)
  • Empty weight: 4,190 lb (1,900 kg)
  • Loaded weight: 5,400 lb (2,449 kg)
  • Powerplant: 1 × Bristol Mercury IX nine-cylinder radial engine, 840 hp (627 kW)



See also

Aircraft of comparable role, configuration and era


  1. Bowyer 1984, p. 34.
  2. James 2000, p. 69.
  3. Goulding 1986, pp. 64–66.
  4. Flight 1937a, p. 18a.
  5. James 1987, p. 227.
  6. Flight 1937, p. 11; Flight 1937a, p. 18a.
  7. James 1987, p. 230.
  8. James 1987, p. 159.
  9. Green & Swanborough 1994, p. 248.
  10. Mason 1992, p. 264.


  • Bowyer, Michael J. F. (1984). Interceptor Fighters for the Royal Air Force, 1935–45. Wellingborough: Patrick Stephens. ISBN 0-85059-726-9.
  • "The Royal Air Force Display". Flight. 1 July 1937. ISSN 0015-3710. Retrieved 30 August 2019.
  • "Debutante Quartet". Flight. 1 July 1937. ISSN 0015-3710. Retrieved 30 August 2019.
  • Goulding, James (1986). Interceptor. Ian Allan. ISBN 0-7110-1583-X.
  • Green, William; Swanborough, Gordon (1994). The Complete Book of Fighters. New York: Smithmark. ISBN 0-8317-3939-8.
  • James, Derek N. (2000). Gloster Aircraft Company (Images of Aviation). Stroud: Tempus. ISBN 0-7524-0038-X.
  • James, Derek N. (1987). Gloster Aircraft since 1917. London: Putnam. ISBN 0-85177-807-0.
  • Mason, Francis K. (1992). The British Fighter Since 1912. Annapolis, Maryland: Naval Institute Press. ISBN 1-55750-082-7.
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