Koolhoven F.K.45

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Role Aerobatic aircraft
National origin Netherlands
Manufacturer N.V. Koolhoven Vliegtuigen
First flight February 1932
Number built 1

The Koolhoven F.K.45 was an aerobatic biplane built to the requirements of one pilot who flew it at airshows in the mid-1930s. Only one was built.

Design and development[edit]

The F.K.45 was the result of a 1931 order from René Paulhan, a French test pilot with Nieuport-Delage, for a light aerobatic aircraft. It was first flown in February 1932, though not delivered to Paulhan for two more years. It was a single bay biplane, with equal span, unswept wings of constant chord and strong stagger, braced with N-form struts and flying wires. Ailerons were mounted on both upper and lower wings. The upper wing of the F.K.45 was held above the fuselage by a pair of short, outward leaning N-form cabane struts to the upper fuselage longerons. The single seat cockpit, set in an opening in the otherwise continuous, rounded fuselage decking, was under the wing trailing edge where a rectangular cut-out enhanced visibility. Its tailplane was mounted on top of the fuselage; the fin was quadrant shaped and the straight edged rudder extended down to the keel.[1]

The F.k.45 was powered by a 115 hp (86 kW) Cirrus-Hermes IIB four cylinder inverted air-cooled inline, which drove a two blade propeller. Its undercarriage was of the fixed, conventional type, with the mainwheels on axles forming an inverted V and attached to the central fuselage underside. The main legs, with shock absorbers, were mounted on the upper longerons. There was a small tailwheel.[1]

Operational history[edit]

The sole F.K.45 initially flew with the test registration Z1, then with the Dutch registration PH-AIF,[1] but when it was handed over to Paulan on 24 April 1934[2] it was placed on the French register as F-AMXT. Paulhan displayed it at airshows over the next two years and then sold it. In August 1938, the F.K.45 had logged only fifty hours of flight.[1] It went on to two more owners[2] but its final fate is unknown.[1]


Data from Wesselink[1]

General characteristics

  • Crew: One
  • Length: 5.57 m (18 ft 3 in)
  • Wingspan: 7.04 m (23 ft 1 in)
  • Gross weight: 580 kg (1,279 lb)
  • Powerplant: 1 × Cirrus-Hermes IIB 4-cylinder inverted air-cooled inline, 86 kW (115 hp)
  • Propellers: 2-bladed


  • Maximum speed: 210 km/h (130 mph; 113 kn) at sea level


  1. ^ a b c d e f Wesselink, Theo; Postma, Thijs (1982). De Nederlandse vliegtuigen. Haarlem: Romem. p. 80. ISBN 90 228 3792 0. 
  2. ^ a b "Golden Years - French registrations". Retrieved 3 March 2013.