Koolhoven F.K.58

In 1938, the French Air Ministry noticed that domestic aircraft manufacturing capacity could not re-equip the Armée de l'Air with modern fighters quickly enough.

In order to win some contracts with the French, the Dutch manufacturer Koolhoven quickly designed a single-seat fighter that would use French-supplied engines and other components.

[7] On 2 July 1939, the Dutch government placed an order on behalf of the Luchtvaart Afdeling (Netherlands Army Aviation Corps) for 36 F.K.58s, to be powered by Bristol Taurus engines.

[9] However, as the British government restricted exports of the Taurus, alternative engines were proposed, including the Rolls-Royce Merlin and the Daimler-Benz DB 600.

[11] The F.K.58s comprising the Dutch order were in various stages of construction when they were destroyed by a German air raid on the Koolhoven factory in May 1940.

Even though Koolhoven credited the F.K.58 prototype with high performance, French test centers recorded that the series aircraft were 120 km/h (75 mph; 65 kn) slower than what was claimed by the manufacturer.

[14] The F.K.58 was originally ordered to serve with AdA units based in French overseas territories,[4] but by the end of 1940, these plans had been abandoned, and attempts were made to dispose of the aircraft, including selling them back to the Netherlands and selling them to Yugoslavia to replace 25 Morane-Saulnier M.S.406s that France had agreed to supply in December 1939 but had since been requisioned by France.

Their official name were patrouilles ("patrols") – as the AdA designated units that defended rear areas against long-range bombers and other enemy aircraft, as part of the Défense Aérienne du Territoire ("Territorial Air Defense"; DAT).

Prototype
The prototype of the F.K.58. in 1938.
Finished fighters at Koolhoven works airfield, 1939. Airplanes bear Dutch civil markings and French military insignia.
3-views of the F.K.58.