NVI F.K.31

NVI F.K.31 was a Dutch designed, two seat reconnaissance-fighter, which was developed in the 1920s by Frederick Koolhoven. The aircraft was equipped with an enclosed cockpit and single-strut landing gear. Only a small number of aircraft were produced. The aircraft saw some service in the Finnish Air Force.

NVI F.K.31
Class Aircraft
Type Fighter
Manufacturer Koolhoven
Origin Netherlands
Country Name Origin Year
Netherlands 1923
Country Name Operational Year Retirement Year
Finland 1925 1927 View
Netherlands 1925 1927 View
ManufacturerName Production From Production To Quantity
Koolhoven 17 View

The F.K.31 became Koolhoven's first design for the N.V. Nationale Vliegtuig Industrie ("National Aircraft Industry") a two seat scout and fighter. Its prototype became the sensation of the Paris Air Salon of 1922. However, the production of the F.K.31 met with many difficulties, forcing the N.V. Nationale Vliegtuig Industrie to close down.

The Finnish Air Force used twelve F.K.31s between 1925-27. The aircraft had been purchased while the development still was being carried out. The Finnish pilots disliked the aircraft and it has been considered the worst aircraft of the FAF. The F.K.31s flew for fewer than 6 hours in the Finnish Air Force.

Role Reconnaissance-fighter
Manufacturer Nationale Vliegtuig Industrie
First flight June 1923
Introduction 1925
Retired 1927
Primary user Finnish Air Force
Number built 17

General characteristics

  • Crew: One, pilot
  • Length: 7.80 m (25 ft 7 in)
  • Wingspan: 13.75 m (45 ft 1 in)
  • Height: 3.40 m (11 ft 2 in)
  • Wing area: 27.20 m² (292.7 ft²)
  • Empty weight: 1,050 kg (2,310 lb)
  • Max. takeoff weight: 1,800 kg (3,960 lb)
  • Powerplant: 1 × Bristol Jupiter IV 9-cylinder radial engine, 313 kW (420 hp)


  • Maximum speed: 235 km/h (126 knots, 145 mph)
  • Service ceiling: 7,200 m (23,616 ft)
  • Endurance: 6 hours


  • 2 × 7.7 mm machine guns

End notes