Nederlandse Modelbouw en Luchtvaartsite

Dutch Modelling and Aviation

In Memoriam

Klaas Willem Jonker
(Wilko)
† April 30, 2018

On Monday 30 April 2018, Wilko Jonker died after a long illness at the age of 58. He leaves behind a wife and two children. The Dutch military aviation and plastic modeling were his hobby and on this website he shared all the knowledge he has collected over the years. His hobby has been able to distract him from the persistent disease in his body until the last week of his life. The contacts with other hobbyists were a major support for him.

This website will be maintained by different people for as long as possible, so that other enthusiasts can continue to benefit from extensive content.

Koolhoven FK.51

History

Early 1935 Koolhoven developed and built the FK.51 at own risk in just 13 weeks. Koolhoven hoped for an order of the LVA, who was looking for a new transitional trainer. The prototype made on May 25, 1935 its first flight.


In June 1935 the plane was a month long evaluated by the LVA and compared with the AVRO Tutor. Ultimately the FK.51 was chosen and the LVA placed an initial order for ten aircraft.

Soon after also orders from the RNlNAS and NEIAF followed and further there was another large order for delivery to Spain.

To handle all this Aviolanda Papendrecht was engaged as a subcontractor. Aviolanda built approximately twenty-five hulls complete with instruments.

The first FK.51s for the LVA, in fact a preproduction series, were delivered in late 1936 and early 1937. From February 1937, they were replacing the Fokker C.I as training aircraft.
In the course of 1937 a second order of the LVA for fifteen pieces followed. These differed with respect to the first ten devices in the sloping vertical fin, a 7.7 mm machine gun in the top left wing. Moreover, these aircraft were painted light blue, while the first ten examples were dark brown.

Later, a third order of the LVA was received for another 29 aircraft, which had to be designed as a light scout. These had, in addition to the machine gun in the upper wing also a machine gun in the rear cockpit, and bomb racks could also be applied.

 

Technical information FK.51 LVA
Dimensions:
Length: 7,9 m Wingspan: 9 m
Height: 2,8 m Wing area: 27 m2
Weights:
Empty weight: 870 kg Max. start weight: 1260 kg
Performances:
Max. speed: 217 km/hr Climbing speed: - m/min
Cruising speed: 185 km/hr    
Range: 500 km Service ceiling: - m
Miscellaneous:
Engine type: One Armstrong Siddeley Cheetah IX rated 350 hp
Crew:

Two men:

trainer: one instructor plus one pupil

Scout; one aviator plus one observer/air gunner

Armament: One 7.7 mm Lewis machine gun mounted in upper wing. One movable machine for the observer;
Note the trainer aircraft were unarmed

 

Technical information FK.51 RNlNAS
Dimensions:
Length: 7,9 m Wingspan: 9 m
Height: 2,8 m Wing area: 27 m2
Weights:
Empty weight: 870 kg Max. start weight: 1260 kg
Performances:
Max. speed: 217 km/hr Climbing speed: - m/min
Cruising speed: 185 km/hr    
Range: 500 km Service ceiling: - m
Miscellaneous:
Engine type: One Wright Whirlwind R-975-E1 rated 365 hp
Crew: Two men:

trainer: one instructor plus one pupil

Scout; one aviator plus one observer/air gunner
Armament:  

 

Technical information FK.51 NEIAF
Dimensions:
Length: 7,9 m Wingspan: 9 m
Height: 2,8 m Wing area: 27 m2
Weights:
Empty weight: 870 kg Max. start weight: 1260 kg
Performances:
Max. speed: 217 km/hr Climbing speed: - m/min
Cruising speed: 185 km/hr    
Range: 500 km Service ceiling: - m
Miscellaneous:
Engine type: One Pratt & Whitney R-985 AN-1 Wasp Jr rated 450 hp
Crew: Two men:

trainer: one instructor plus one pupil

Scout; one aviator plus one observer/air gunner
Armament: