Koolhoven F.K.57
| F.K.57 | |
|---|---|
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| |
| Role | Executive transport |
| National origin | Netherlands |
| Manufacturer | N.V. Koolhoven Vliegtuigen , Rotterdam
|
| Designer | Frederick Koolhoven |
| First flight | 20 June 1938 |
| Primary user | J.E.F. de Kok |
| Number built | 1 |
The Koolhoven F.K.57 was a twin-engined, gull-winged monoplane built in the
Design and development
One of the first aircraft designed as a luxury tourer and aimed in part at the owners and CEOs of large companies as their personal transport was the
The F.K.57 was a gull-winged monoplane with a fixed undercarriage, twin tail and cabin for four. The section of wing inboard of the undercarriage had spars which were an integral part of the fuselage structure. Though the wing root was at the bottom of the fuselage, these inner sections had strong dihedral so that the outer parts of the wings, beyond undercarriage and engines, were at a mid-wing position.[3] Koolhoven had used this gull wing arrangement on some earlier aircraft and claimed it combined the stability advantage of the mid wing layout, due to its low centre of gravity with the structural simplicity of the low wing layout.[1] The wings were built up around two box spars, with plywood ribs and bakelite ply covering. The two 205 hp (153 kW) de Havilland Gipsy Six inverted inline engines were mounted at the junction of inner and outer wings in steel tube structures, below the wings but with cowlings faired into them. Twin bladed variable pitch, constant speed propellers rotated into the same direction. Short, fixed, cantilever shock absorbing undercarriage legs were mounted under each engine, normally with faired legs and spatted wheels.[3]
The fuselage was a monocoque wooden structure, flat sided but with a rounded top running from above the cabin to the tail. The cabin seated four in two rows; the two forward seats had dual control and behind them was a carrier for food and a folding table on the starboard side. There was also a refrigerator. Behind the rear seats was a panel with sliding door access to a starboard side toilet The corresponding port-side space was a baggage compartment accessible only from outside. Entry to the cabin was via an over-wing port side door. The tail unit was a cantilever structure with the tailplane an integral part of the upper fuselage, carrying endplate fins with straight swept leading edges above the tailplane and rounded below. The fixed surfaces were plywood skinned, but rudders and the elevator were fabric covered. These control surfaces had in-flight adjustable trim tabs.
Operational history
On 22 September 1938 the F.K.57 headed out from
Specifications
Data from Grey 1972[4]
General characteristics
- Crew: 1/2
- Capacity: 2/3 (4 people in all)
- Length: 9.0 m (29 ft 6 in)
- Wingspan: 13.25 m (43 ft 6 in)
- Height: 2.4 m (7 ft 10 in)
- Wing area: 23.6 m2 (254 sq ft)
- Empty weight: 1,380 kg (3,042 lb)
- Gross weight: 2,160 kg (4,762 lb)
- Powerplant: 2 × de Havilland Gipsy Six Series II 6-cylinder air-cooled inverted inline, 153 kW (205 hp) each
Performance
- Maximum speed: 280 km/h (170 mph, 150 kn) at sea level. All performance figures are estimates.
- Cruise speed: 260 km/h (160 mph, 140 kn) at 1,830 m (6,000 ft)
- Range: 1,400 km (870 mi, 760 nmi)
- Service ceiling: 6,000 m (20,000 ft)
- Rate of climb: 6.1 m/s (1,200 ft/min) initial rate
References
- ^ a b c Flight 6 October 1938 p.302
- ^ a b c "Koolhoven FK57". Archived from the original on 2009-12-07. Retrieved 2010-01-01.
- ^ a b c Grey 1972, pp. 217c–218c.
- ^ Grey 1972, p. 218c.
Cited sources
- Grey, C.G. (1972). Jane's All the World's Aircraft 1938. London: David & Charles. ISBN 0-7153-5734-4.