Armstrong Whitworth F.K.10

The Armstrong Whitworth F.K.10 was a British two seat quadriplane (i.e., four wing) fighter aircraft built by Armstrong Whitworth during the First World War. While it was ordered in small numbers for the Royal Flying Corps and Royal Naval Air Service, it was not used operationally. It is one of the few quadruplane aircraft to reach production. 

Armstrong Whitworth F.K.10
Class Aircraft
Type Fighter
Manufacturer Armstrong Whitworth
Production Period 1916 - 1916
Origin United Kingdom - UK (Great Britain)
Country Name Origin Year
United Kingdom - UK (Great Britain) 1916
Country Name Operational Year Retirement Year
United Kingdom - UK (Great Britain) View
ManufacturerName Production From Production To Quantity
Armstrong Whitworth 1916 1916 9 View

The F.K.10 was designed in 1916 by Frederick Koolhoven, the chief designer of Armstrong Whitworth Aircraft as a single engined two seat fighter. Koolhoven chose the novel quadruplane layout. At roughly the same time, Sopwith were building the successful Sopwith Triplane fighter. 

The first prototype, the F.K.9 was built and first flown in the summer of 1916, powered by a 110 hp Clerget 9Z engine. It had a shallow fuselage, with the wings joined by plank-like interplane struts, similar to those used by the Sopwith Triplane. After evaluation at the Central Flying School in late 1916, a production order for 50 was placed by the RFC for a modified version, the F.K.10. 

The production F.K.10 had a new, deeper fuselage, and a new tail, but retained the wing planform of the F.K.9. The F.K.10 showed inferior performance to the Sopwith 1 Strutter, which was already in service as a successful two seat fighter, and only five were built of the RFC order, with a further three built for the RNAS. They were not used operationally and the design was not developed further. 


  • F.K.9 : Prototype powered by 110 hp (80 kW) Clerget 9Z engine.
  • F.K.10 : Production version with revised fuselage and tail, powered by 130 hp (100 kW) Clerget 9B or Le Rhône 9J engine. 50 ordered, 8 built. 

Role Fighter
Manufacturer Armstrong Whitworth
Designer Frederick Koolhoven
First flight 1916
Number built 9 (1 F.K.9 + 8 F.K.10)

General characteristics

  • Crew: One
  • Length: 22 ft 3 in (6.78 m)
  • Wingspan: 27 ft 10 in (8.48 m)
  • Height: 11 ft 6 in (3.50 m)
  • Wing area: 390 ft (26.3 m)
  • Empty weight: 1,236 lb (562 kg)
  • Loaded weight: 2,019 lb (918 kg)
  • Powerplant: 1 x Clerget 9B rotary engine, 130 hp (97 kW)


  • Maximum speed: knots (84 mph, km/h) at 6,500 ft (2,000 m)
  • Service ceiling 10,000 ft (3,050 m)
  • Wing loading: lb/ft (kg/m)
  • Power/mass: hp/lb (W/kg)
  • Endurance: 2.5 hours
  • Climb to 10,000 ft (3,050 m): 37 min 10 sec


  • One forward firing .303 in (7.7 mm) Vickers machine gun and one .303 in (7.7 mm) Lewis gun in observers cockpit

End notes