The Gloster Gamecock was a biplane fighter of the Royal Air Force, a development of the Mk III Grebe, that first flew in February 1925. It differed from the Grebe primarily by way of its Bristol Jupiter engine, which replaced the unreliable Armstrong Siddeley Jaguar. Other changes included improved ailerons, refined fuselage contours, and internally mounted machine guns.

Three prototypes were ordered, the first aircraft (J7497) flying for the first time on 22nd February 1925 with production aircraft (Gamecock I) using a 425 hp Jupiter VII engine. The type inherited the excellent performance and handling of the Grebe, although, like the Grebe, it also suffered from spin recovery and wing flutter issues.

The Gamecock Mark I entered service with No. 23 Squadron RAF at RAF Henlow in May 1926 and they were also the last of six squadrons to operate the fighter until July 1931. This was a fairly short RAF service life, partly because of its high accident rate ? of the 90 operated by the RAF, 22 were lost in landing or spin accidents. These faults were remedied in the Mk. II version, by means of a longer upper wing and a modified tail unit.

Three Gamecock I were supplied to Finland, where the type was put into production as the Kukko, 15 being built by the Finnish National Aircraft Factory.
During the Finnish Winter War 1939?40, a Gamecock was used to capture a Soviet Ilyushin DB-3 bomber. On 29 January 1940 the Finnish Gamecock strafed two Soviet DB-3s when they landed on Finnish soil (which they mistook for Estonia) to transfer fuel from one plane to the other. The strafed crews hurried into the one plane which had enough fuel remaining and escaped, leaving the DB-3 behind to be captured by the Finns.

Specifications (Mk. I)
General characteristics
Crew: one, pilot
Length: 19 ft 8 in (5.99 m)
Wingspan: 29 ft 9? in (9.07 m)
Height: 9 ft 8 in (2.94 m)
Wing area: 264 ft? (24.52 m?)
Empty weight: 1,930 lb (875 kg)
Loaded weight: 2,860 lb (1,297 kg)
Powerplant: 1 ? Bristol Jupiter VI 9-cylinder radial, 425 hp (317 kW)
Performance
Maximum speed: 155 mph (135 knots, 250 km/h) at 5,000 ft (1,520 m), 145 mph (126 knots, 233 km/h) at 10,000 ft (3,050 m)
Range: 365 mi (316 NM, 587 km)
Service ceiling: 22,100 ft (6,735 m)
Rate of climb: 7,066 ft/min (36 m/s) at 1,000 ft (305 m)
Wing loading: 10.8 lb/ft? (52.9 kg/m?)
Power/mass: 0.15 hp/lb (0.24 kW/kg)
Climb to 10,000 ft (3050 m): 7.6 min
Endurance: 2.5 hours
Armament
Guns: 2?0.303 inch (7.7mm) Vickers machine guns