The Koolhoven F.K.50 was a 1930s Dutch eight-passenger light transport monoplane designed and built by Koolhoven.
The F.K.50 was designed to meet a requirement from the Swiss airline Swiss Alpar for a light transport capable of operating in Switzerland. The F.K.50 was a cantilever high-wing cabin monoplane with a fixed wide track tailwheel landing gear. The fuselage was of welded steel tube construction, covered with fabric. The tailplane was of similar construction. The wings were wooden construction, covered with plywood. It was powered by two Pratt & Whitney Wasp Junior T1B engines and had a conventional single fin and rudder. The first of two aircraft first flew on the 18 September 1935 and the second flew in March 1936.[1]
A third aircraft, designated F.K.50A, was built in 1938 with a re-designed tail unit with twin vertical tail surfaces. It had a longer nose and larger mainwheels, with a higher all-up weight.[1]
Two bomber variants, designated F.K.50B, were proposed but never built. The first was a straight conversion of the F.K.50; the second would have been powered by 830hp Bristol Mercury VIS radial engines. It would have been operated by a crew of four and carried a 2200lb bomb load.[1]
The three aircraft operated a regular service between Swiss destinations and onwards to Lyons and Marseilles and charter flights to Paris and London.