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Koolhoven F.K.58 Fighter / Interceptor (1940)

Authored By Staff Writer | Last Updated: 10/14/2015

Only thirteen or so complete examples of the Dutch Koolhoven F.K.58 fighter were available for May-June 1940.

Prior to its conquer at the hands of Nazi Germany, the Netherlands held a viable, standalone aero-industry led by names like Fokker and Koolhoven. While there proved no single stand-out design when compared to larger players of the interwar years, some impressive models emerged such as the Fokker D.XXI fighter and G.I "Reaper" heavy fighter. Koolhoven contributed with the F.K.56 trainer, the F.K.55 fighter prototype and the F.K.58 production fighter.

For the latter, design was led by Erich Schatzki and the aircraft was originally intended to serve over both Dutch and French colonial holdings where it would have made for an excellent security measure. The French Air Force adopted it as a fighter / interceptor to help shore up its own strained aero-industry. Since economy was the call of the day, the platform was to have good performance qualities against contemporaries but also be relatively inexpensive and easy to build in number. Schatzki had already put his design talents to use in the Fokker D.XXI (detailed elsewhere on this site) so the F.K.58 served as something of an extension of that work. A first flight, through prototype Model 1166, was held on July 17th, 1938 though only twenty went on to be completed as the Dutch fell in the early going against Germany.

Outwardly, the F.K.58 was of an all-modern fighter - metal understructures, an enclosed cockpit and retractable undercarriage were some of its features. Dimensions included a length of 28.7 feet, a wingspan of 36 feet and a height of 9.9 feet. Empty weight was 4,255 pounds against a loaded weight of 6,065 pounds. Standard, fixed armament ended as 4 x 7.5mm FN-Browning machine guns fitted under each wing mainplane (two guns per wing).

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Specifications for the
Koolhoven F.K.58
Fighter / Interceptor

Focus Model: Koolhoven F.K.58
Country of Origin: Netherlands
Manufacturer: Koolhoven - Netherlands
Initial Year of Service: 1940
Production Total: 20

Crew: 1

Length: 28.54 ft (8.7 m)
Width: 36.09 ft (11.00 m)
Height: 9.84ft (3.00 m)
Weight (Empty): 4,255 lb (1,930 kg)
Weight (MTOW): 6,063 lb (2,750 kg)

Powerplant: 1 x Gnome-Rhone 14N-16 radial piston engine developing 1,030 horsepower.

Maximum Speed: 314 mph (505 kmh; 273 kts)
Maximum Range: 466 miles (750 km)
Service Ceiling: 32,808 ft (10,000 m; 6.2 miles)
Rate-of-Climb: 1,130 feet-per-minute (344 m/min)

Hardpoints: 0
Armament Suite:
4 x 7.5mm FN-Browning machine guns in fairings held under the wings (two guns per wing).

F.K.58 (Prototype) - Prototype model; fitted with Hispano-Suiza 14AA radial engine of 1,080 horsepower; 2 examples produced.

FK-58 (Bristol Taurus) - Proposed Dutch production version; to be Fitted with Bristol Taurus engine; never produced.

F.K.58 - Initial Production Model; fitted with Hispano-Suiza 14AA radial engine; 7 examples produced.

F.K.58A - Second Batch Production; fitted with Gnome-Rhone 14N-16 series radial engine of 1,030 horsepower; 11 examples produced.

France; Poland