Koolhoven F.K.56

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Koolhoven F.K.56
Role Basic training monoplane
National origin Netherlands
Manufacturer Koolhoven
First flight 30 June 1938
Primary user Netherlands Army
Number built 31

The Koolhoven F.K.56 was a 1930s Dutch basic training monoplane designed and built by Koolhoven.[1]


The F.K.56 was a low-wing monoplane powered by a 450 hp (336 kW) Wright Whirlind R-975-E3 radial piston engine.[1] Designed as a basic trainer, the F.K.56 had two seats in tandem for the instructor and pupil under a fully enclosed canopy.[1] The first prototype flew on 30 June 1938 and had fixed conventional landing gear and an inverted gull wing.[1] The second prototype had retractable landing gear while a third prototype was fitted with a straight wing and dual controls.[1]

Ten aircraft were ordered by the Netherlands Army based on the design of the third prototype.[1] These ten, including the re-worked first and third prototypes, were all delivered before the German invasion of the Netherlands in May 1940.[1]

Earlier in February 1940 the Belgians had ordered twenty F.K.56 basic trainers and seven had been delivered before the rest were destroyed in an air raid on the Waalhaven factory.[1]




Data from [1]

General characteristics

  • Crew: 2
  • Length: 7.85 m (25 ft 9 in)
  • Wingspan: 11.50 m (37 ft 9 in)
  • Height: 2.30 m (7 ft 7 in)
  • Wing area: 20 m2 (220 sq ft)
  • Empty weight: 1,058 kg (2,332 lb)
  • Max takeoff weight: 1,600 kg (3,527 lb)
  • Powerplant: 1 × Wright Whirlwind R-975-E3 Radial piston engine, 336 kW (451 hp)


  • Maximum speed: 300 km/h (186 mph; 162 kn) at a height of 500m (1640 ft)
  • Range: 800 km (497 mi; 432 nmi)
  • Service ceiling: 7,300 m (24,000 ft)



  1. ^ a b c d e f g h i Orbus 1985, p. 2272