The Koolhoven F.K.50 was a 1930s

Dutch Dutch commonly refers to: * Something of, from, or related to the Netherlands * Dutch people () * Dutch language () Dutch may also refer to: Places * Dutch, West Virginia, a community in the United States * Pennsylvania Dutch Country People E ...

eight-passenger light transport

monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...

designed and built by

Koolhoven N.V. Koolhoven was an aircraft manufacturer based in Rotterdam, Netherlands. From its conception in 1926 to its destruction in the Blitzkrieg in May 1940, the company remained the second major Dutch aircraft manufacturer (after Fokker). Althoug ...

Development

The F.K.50 was designed to meet a requirement from the

Swiss Swiss may refer to: * the adjectival form of Switzerland * Swiss people Places * Swiss, Missouri * Swiss, North Carolina *Swiss, West Virginia * Swiss, Wisconsin Other uses *Swiss-system tournament, in various games and sports *Swiss Internation ...

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 The Pratt & Whitney R-985 Wasp Junior is a series of nine-cylinder, air-cooled, radial aircraft engines built by the Pratt & Whitney Aircraft Company from the 1930s to the 1950s. These engines have a displacement of ; initial versions produced , ...

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. 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. 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

Bristol Mercury The Bristol Mercury is a British nine-cylinder, air-cooled, single-row, piston radial engine. Designed by Roy Fedden of the Bristol Aeroplane Company it was used to power both civil and military aircraft of the 1930s and 1940s. Developed from ...

VIS

radial engine The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ca ...

s. It would have been operated by a crew of four and carried a bomb load.

Operational history

The three aircraft operated a regular service between Swiss destinations and onwards to

Lyon Lyon,, ; Occitan: ''Lion'', hist. ''Lionés'' also spelled in English as Lyons, is the third-largest city and second-largest metropolitan area of France. It is located at the confluence of the rivers Rhône and Saône, to the northwest of t ...

s and

Marseilles Marseille ( , , ; also spelled in English as Marseilles; oc, Marselha ) is the prefecture of the French department of Bouches-du-Rhône and capital of the Provence-Alpes-Côte d'Azur region. Situated in the camargue region of southern Franc ...

and charter flights to Paris and London.

F.K.50

;HB-AMI The first to be built, the aircraft entered service in October 1935. During

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

, the aircraft operated weekly between

Berne german: Berner(in)french: Bernois(e) it, bernese , neighboring_municipalities = Bremgarten bei Bern, Frauenkappelen, Ittigen, Kirchlindach, Köniz, Mühleberg, Muri bei Bern, Neuenegg, Ostermundigen, Wohlen bei Bern, Zollikofen , website ...

and

Croydon Croydon is a large town in south London, England, south of Charing Cross. Part of the London Borough of Croydon, a local government district of Greater London. It is one of the largest commercial districts in Greater London, with an extensi ...

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

. The aircraft was scrapped in 1947. ;HB-AMO The second to be built, the aircraft crashed on landing 25 kilometers from

Basle Airport EuroAirport Basel Mulhouse Freiburg IATA airport 3-letter codes for the French area, the Swiss area, and the metropolitan area, french: Aéroport de Bâle-Mulhouse-Fribourg, it, Aeroporto di Basilea-Mulhouse-Friburgo, rm, Eroport da Basilea-Mu ...

on 10 September 1937 with the loss of three lives.

F.K.50A

;HB-AMA The sole F.K.50A, the aircraft was delivered in 1938. It also operated between Berne and Croydon during World War II. In 1947, it was sold to Liberian operator Maryland Flying Services and re-registered EL-ADV, operating with them until 6 July 1962 when it crashed near

Monrovia Monrovia () is the capital city of the West African country of Liberia. Founded in 1822, it is located on Cape Mesurado on the Atlantic coast and as of the 2008 census had 1,010,970 residents, home to 29% of Liberia’s total population. As the ...

Variants

;F.K.50 :Two built, single vertical tail. The second aircraft had larger engine nacelles than the first. ;F.K.50A :One built, twin tail, longer nose, bigger mainwheels, Higher all-up weight. ;F.K.50B :Proposed Bomber variant, not built.

Operators

; * ; *Maryland Flying Services

Specifications (F.K.50)

References

Sources

* * {{Koolhoven aircraft FK.50 1930s Dutch airliners Aircraft first flown in 1935 Twin piston-engined tractor aircraft High-wing aircraft