Koolhoven F.K.58

https://en.wikipedia.org/wiki/Koolhoven_F.K.58

The Koolhoven F.K.58 was a single engine, interceptor-fighter aircraft designed
and mainly manufactured by N V Koolhoven in the Netherlands under contract by
France. Intended for Armée de l'Air use, the F.K.58 saw limited service in the
Battle of France.

In 1937, the French Conseil Supérieur de l'Air decided that domestic aircraft
manufacturing capacity could not, in the event of war, equip the Armée de l'Air
with fighters quickly enough. The Dutch manufacturer Koolhoven was contracted to
design a cheap, easily built, high-performance fighter, that could be built and
serviced with French-supplied engines and other components. According to some
sources, the Koolhoven fighter was intended primarily for fighter units based in
French colonies.

On 17 July 1938, the prototype Koolhoven Model 1166 (later renamed the F.K.58)
flew for the first time. Designed by Erich Schatzki – a Jewish refugee from
Germany – the F.K.58 may be seen as a development of his preceding fighter
design: the Fokker D.21. The F.K.58 used the same composite materials as the
D.21: the structure of the fuselage consisted of welded steel tubing covered
with sheet metal (front part) and fabric (aft); the wings had wooden members
with a plywood and fabric skin.

In July 1939, the Dutch government placed an order on behalf of the Luchtvaart
Afdeling (Netherlands Army Aviation Corps) for 36 F.K.58 variants, powered by
Bristol Taurus engines. As the British government restricted exports of
Tauruses, they were to be replaced by Dutch stocks of the Bristol Mercury VIII
(as used by the Dutch Fokker D.21 and Fokker G.1A). The lower output of the
Mercury, relative to the Taurus, would have allowed a top speed to some 480
km/h.

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.

Had the Armée de l'Air received its full order of 50 aircraft, before for the
Battle of France, it is unlikely that they would have changed the outcome. The
F.K.58s that became operational were regarded as superior to the Morane-Saulnier
M.S.406, comparable to the Bloch MB.151, and inferior to the Dewoitine D.520, as
well as the latest German fighters.


Role
Fighter

Manufacturer
Koolhoven

Designer
Erich Schatzki

First flight
17 July 1938

Introduction
1940

Retired
1940

Primary users
French Air Force
Polish Air Force

Produced
1939-1940

Number built
20


The F.K.58 was originally procured for use as colonial fighters. Instead, the 13
fighters operational by May 1940 were manned by expatriate Polish pilots of
Captain Walerian Jasionowski's improvised squadron, the patrouille DAT (Défense
Aérienne du Territoire), based at Salon and Clermont-Aulnat (now
Clermont-Ferrand Auvergne Airport). As delivered, the fighters were not armed
and the Poles had to acquire machine guns and fit them. From 30 May 1940, they
were used in the defence of French cities, patrolling in Avignon - Marseille
area, then from Clermont-Ferrand, without any encounters with the enemy. The
type's service life was short-lived with only 47 or so operational sorties
recorded; the unit had no confirmed victories, but at least one F.K.58 was lost.
After the fall of France, all surviving airframes were scrapped.

Specifications (F.K.58)

General characteristics
Crew: One
Length: 8.7 m (28 ft 6.75 in)
Wingspan: 11 m (36 ft 1.25 in)
Height: 3 m (9 ft 10 in)
Wing area: 17.3 m² (186.2 ft²)
Empty weight: 1,930 kg (4,255 lb)
Loaded weight: 2,750 kg (6,063 lb)
Powerplant: 1 × Gnome-Rhône 14N-16 radial engine, 768 kW (1,030 hp)

Performance
Maximum speed: 505 km/h (314 mph)
Cruise speed: 450 km/h (280 mph)
Range: 750 km (466 mi)
Service ceiling: 10,000 m (32,810 ft)
Rate of climb: 11.6 m/s (1,130 ft/min)
Wing loading: 159 kg/m² (32.6 lb/ft²)
Power/mass: 0.28kW/kg (0.17 hp/lb)

Armament

4 x 7.5 mm FN-Browning machine guns in underwing fairings





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