Dutch Modelling and Aviation

In Memoriam

Klaas Willem Jonker
(Wilko)
† April 30, 2018

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

Koolhoven FK.56

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History

The Koolhoven Fk.56 was developed in response to the needs of the LVA new training aircraft for the advanced training.

For the construction of the prototype, construction number 5601 and (later) civil registration PH-ASB, the hull of a FK.51 was used.

The centre section was removed and replaced with a new part, with two cockpits with one canopy and a gull wing (Frits Koolhoven had an unjustified dislike of low-deckers, the gull wing was a kind of compromise). On June 30, 1938 the first flight was made and in the autumn the Fk.56 was offered to the LVA for testing.

The type was compared with the Focke-Wulf FW.56 Stösser.

The Koolhoven was chosen and a first order for ten aircraft placed.

A second prototype, construction number 5602 and civil registration PH-ATE, was built with some adjustments, e.g. a retractable undercarriage, a Amrstrong-Siddeley Cheetah engine, a modified fuselage, enlarged rear cockpit with possibility for applying a machine gun and a adjustable canopy, now more in line with that of the Koolhoven Fk.58.

Also a third prototype was built, a pre production version for the LVA, with construction number 5603.

Led by ir Schatzki, who had worked for Fokker, a number of changes have been made; the engine became a Wright Whirlwind of 420 hp, the tail was modified and became identical to that of the Fk.58 and the gull wing was replaced by a straight wing, which was quite high joined to the fuselage and the retractable undercarriage was further improved and customized.

On January 4, 1940 was a last test flight was made. Because of flutter the wing broke off and the aircraft crashed.

The cause proofed to be lack of using diagonal laminated plywood. The wings were also modified and built with diagonal plywood.

A new copy with construction number 5613 was built. Before the crashed device

Meanwhile Koolhoven had received an order for twenty aircraft from Belgium. The LVA also placed  a follow-up order for another ten examples.

Because of the war not all aircraft were delivered.

 

Technical information
Dimensions:
Length: 7,9 m Wingspan: 11,5 m
Height: - m Wing area: - m2
Weights:
Empty weight: - kg Max. start weight: - kg
Performances:
Max. speed: 300 km/hr Climbing speed: - m/min
Cruising speed: - km/hr    
Range: - km Service ceiling: - m
Miscellaneous:
Engine type: One Wright Whirlwind R-975-53 rated 400 hp
Crew: Two: one instructor plus one pupil
Armament: None

 


Two seat training aircraft, developed from the Koolhoven FK-51, for advanced training.
At the beginning 1940 six aircraft were delivered of the ordered first series of ten aircraft.

These aircraft were stationed at the flying school at Texel. All were destroyed due to the bombardments on May 10 and May 11, 1940.

 

Trillingsproeven op Koolhoven FK.56 1001. Foto in NLL rapport V.1213. Rechts FK.56 1005 (PH-ASB)
Koolhoven Fk.56 serial 52
[Enclosed photo from BeeldBank NIMH. Click on photo for ordering information]
Koolhoven FK.56 81, rechts.
Koolhoven FK.56 81.
[Enclosed photo from BeeldBank NIMH. Click on photo for ordering information]
Koolhoven FK.56 85 op Soesterberg, april 1940.
Koolhoven FK.56 85 at Soesterberg, April 1940.
[Enclosed photo from BeeldBank NIMH. Click on photo for ordering information]
Wrak van een Koolhoven FK.56 op Texel, mei 1940.
Wreck of a Koolhoven FK.56 at Texel, May 1940.
[Enclosed photo from BeeldBank NIMH. Click on photo for ordering information]

 


SerialConstruction nr.Date in serviceDate out of serviceNotes
81 5613 02-1940 11-05-1940 Replacement of the crashed first 81, with c.n. 5603.
82 5604 02-1940  11-05-1940   
83 5605 02-1940 11-05-1940  
84 5606 02-1940 11-05-1940  
85 5607 02-1940 11-05-1940  
86 5608 02-1940 11-05-1940  
Uncertain whether these aircraft are delivered
87 5609 02-1940  11-05-1940  
88 5610 02-1940  11-05-1940  
89 5611 02-1940  11-05-1940  
90 5612 02-1940 11-05-1940  

 


1/72nd Scale

Kits

  • Omega
    • Kit 72234 / 72235: Resin kit with decals for a LVA and Belgian aircraft respectively.
  • Dujin
    • Kit A72162: A resin kit
  • VAMI
    • Kit XX: A resin kit

Modelling add-on

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Decals

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1/48th Scale

Kits

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Modelling add-on

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Decals

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 .

SchemeColor nameFS numberWEMHumbrolXtraColorVallejo Model ColorVallejo Model Air
Standard #1Overall LVA BLue   AC D05 115 ? X-214?    

Check www.paint4models.com for an extensive conversion table with lots of colour and paint systems.

 


Literature.

Van Brik tot Starfighter H. Hooftman   1965 La Rivière en Voorhoeve - Zwolle
Nederlandse Militaire Luchtvaart in Beeld. deel 1. Hugo Hooftman Pag. 138 - 139 1977 Uitgever: Europese Bibliotheek, Zaltbommel
Koolhoven Nederlandse vliegtuigbouwer in de schaduw van Fokker Theo Wesselink & Thijs Postma Pag. 109 - 124 1981 Uitgever: Unieboek b.v., Houten
De Nederlandse Vliegtuigen: Alle vliegtuigen ooit in Nederland ontworpen en gebouwd Theo Wesselink & Thijs Postma Pag. 112 1982 Uitgever: Romen Luchtvaart, Haarlem
KLu Vliegtuigen: De vliegtuigen van de Koninklijke Luchtmacht vanaf 1913 Wim Schoenmaker & Thijs Postma Pag. 75 1987 Uitgeverij De Alk, Alkmaar
Camouflage en Kentekens J.Greuter e.a.   1997 Bonneville – Bergen (NH)

 

Websites.

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