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.

 

 

 

 

In service with LVA; RNlNAS and NEIAF.

In service with LVA.

The first series of ten aircraft was intended as a training aircraft for advanced pilot training. They received the registration 1 to 10 and were, different from the conventional, light blue Colour scheme of the training aircraft of the LVA, overall dark brown. These aircraft looked very similar to the prototype, but they had a more powerful engine.

The second series of registrations 11 to 25 was painted entirely blue.

The third and last series, referred to as a light scouts, registration with 400 to 428 was sprayed overall dark brown.

Soon these aircraft proved not useful for operational reconnaissance purposes and were mainly used for training.

During the armistice in May 1940 the trainers were stationed at Soesterberg and Haamstede. A part of the flight school was moved to Haamstede during the mobilization.

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The scouts were placed with 2LvR and divided into four groups.

These groups were stationed as follows; 1st reconnaissance group, I./2 LvR was stationed with four aircraft at Hilversum; II./2LvR was stationed at Ypenburg with five FK.51s ; III./2LvR was based at Ruigenhoek with four aircraft and finally IV./2LvR was stationed at Gilze-Rijen with five aircraft.

During the war days they were not used for reconnaissance.

On May 10, 1940 one FK.51 was lost at Hilversum during the attack in the early morning, two other FK.51s were damaged. The same day the remaining aircraft were evacuated to Middenmeer and later flown to Ruigenhoek.

The remaining aircraft were destroyed there after the capitulation.

During attacks KF-51 421 was damaged was at Gilze-Rijen. The group IV./LvR was instructed to evacuate to Haamstede; The 415 was not flyable so only 411 left with two Fokker C.V to Haamstede and shortly thereafter shot to fire.

 

 

 

 

 

In service with RNlNAS.

In August 1935 the Koolhoven FK.51 was evaluated at naval air station De Kooy Partly under the influence of the order by the LVA, it was decided to order a series of FK.51s to replace the Fokker D.VII and Fokker C.I for the continued flight training.  On August 1, 1936 a first batch of six aircraft was ordered. These were fitted with a Wright Whirlwind R-975-E1 radial engine. The devices could eventually be converted for reconnaissance . On June 18, 1937 a second order for a further nine aircraft followed. The last three of which were delivered as a scout.

The aircraft proved to be very robust, but had a pretty bad view. Reason to doubt the usability as a scout.

After the accident with the E-1 and E-6, in May 1938, research showed that there were cracks in the wooden Astra durabel propellers, so the FK.51s were grounded between May and August 1938. The air screws were replaced with new screws from Aircscrews Ltd.

Until the early spring of 1940, the aircraft were well used for neutrality patrols, but during the May days they were not operational deployed and all were most probably destroyed during air raids on De Kooy.

 

In service with NEIAF.

 The NEIAF ordered between 1935 and 1939 sixty FK.51s spread over four orders. These were to replace the AVRO 504.

The last fifteen aircraft were not delivered due to the German invasion in May 1940. They stood, awaiting the engines at the factory at Waalhaven and and were completely lost during the bombing on may 10, 1940.

The devices were placed at the flying school at Kalidjati.

In September, the aircraft had, just as in the Netherlands, orange triangles applied and later in 1940, a new registration system was implemented, in which the registration of the remaining devices was increased by 100.

De FK.51 was from 1940, gradually replaced by Ryan STM.

At the outbreak of the war on December 7, 1941 were still about twenty aircraft left, which still were used for reconnaissance and for control of the camouflage.

They were assigned to the third and fifth division of the sixth aircraft group, VLG VI. (3-VLG-VI and 5-VLG-VI).

After February 25, 1942, they are no longer operationally deployed. The remaining aircraft that were not destroyed during the bombings, were destroyed on March 8, 1942 at the capitulation.

 

Serial overview LVA; MLD and NEIAF.

Serial overview RNlNAS.

Serial Serial	Constr. nr. Constr. nr.	Date in service Date in service	Date out of service Date out of service	Notes notes
Ordering date 01-08-1936
E-1	51.12	1936	10-05-1938	Entered service in 1936. Crashed near Eelde
E-1-II	51.124	05-1939	10-05-1940	Ordering date: 20-09-1938. Entered service may 1939 as a replacement for first E-1. Destroyed bombardment air base De Kooy.
E-2	51.13	1936	10-05-1940	Entered service in 1936. Destroyed bombardment air base De Kooy
E-3	51.14	1936	10-05-1940	Entered service in 1936. Destroyed bombardment air base De Kooy
E-4	51.15	1936	10-05-1940	Entered service in 1936. Destroyed bombardment air base De Kooy
E-5	51.16	1936	10-05-1940	Entered service in 1936. Destroyed bombardment air base De Kooy
E-6	51.30	1936	11-05-1938	Entered service in1936. Crashed near Breezand
E-6-II	51.125	05-1939	10-05-1940	Ordering date: 20-09-1938. Entered service may 1939 as a replacement for first E-6. Destroyed bombardment air base De Kooy.
Ordering date 18-06-1937; All were delivered in 1937 and destroyed on Naval air station De Kooy due to bombardment om May 10, 1940
E-7	51.53	1937	10-05-1940
E-8	51.54	1937	10-05-1940
E-9	51.55	1937	10-05-1940
E-10	51.56	1937	10-05-1940
E-11	51.57	1937	10-05-1940
E-12	51.58	1937	10-05-1940
E-13	51.59	1937	10-05-1940
E-14	51.60	1937	10-05-1940
E-15	51.61	1937	10-05-1940

 

Serial overview LVA.

Serial Serial	Constr. nr. Constr. nr.	Date in service Date in service	Date out of service Date out of service	Notes notes
1	5102	08-1936	10-05-1940	Destroyed bombardment naval air station De Kooy
2	5103	08-1936	05-1940
3	5104	08-1936	05-1940
4	5105	08-1936	05-1940
5	5106	08-1936
6	5107	23-09-1936
7	5108	23-09-1936
8	5109	05-10-1936	15-07-1938	Accident. Written off.
9	5110	02-10-1936	10-05-1940
10	5111	03-11-1936	01-12-1938	Crashed near Breezand
11		03-12-1937	10-05-1940	Destroyed bombardment naval air station De Kooy
12		03-12-1937	05-08-1938
13		13-12-1937	10-05-1940	Destroyed bombardment naval air station De Kooy
14		09-02-1938	14-05-1940	Captured at Haamstede (and tested by the Germans)
15		09-02-1938
16		09-02-1938	21-03-1938	Accident. Written off
17		09-02-1938
18		09-02-1938	14-08-1939	Accident. Written off
19		09-02-1938	14-05-1940	Captured by the Germans
20		09-02-1938	15-07-1938
21		09-02-1938
22		09-02-1938	02-08-1938	Accident. Written off
23		09-02-1938	05-1940
24		11-01-1938
25		09-02-1938
400		11-10-1937
401		16-10-1937
402		19-11-1937
403		21-11-1937
404		27-11-1937	19-04-1939	Accident. Written off
405		03-12-1937
406		03-12-1937
407		03-12-1937
408		06-12-1937	14-05-1940
409		09-02-1938
410		18-01-1938
411		18-01-1938	13-05-1940	Shot to fire at Haamstede
412		18-01-1938	01-05-1940
413		09-02-1938
414		09-02-1938
415		09-02-1938	10-05-1940	Unable to fly after German attacks of Gilze-Rijen.
416		09-02-1938
417		09-02-1938
418		09-02-1938	05-1940
419		09-02-1938	14-05-1940
420		09-02-1938		Accident. Written off
421		11-02-1938	10-05-1940	Heavily damaged during German attacks of Gilze-Rijen
422		11-02-1938
423		18-02-1938
424		18-02-1938	26-09-1939	Accident. Written off
425		21-02-1938
426		25-02-1938	14-05-1940
427		25-02-1938
428		11-03-1938	14-05-1940

 

Serial overview NEIAF

Serial Serial	2nd Serial 2nd Serial	Constr. nr. Constr. nr.	Date in service Date in service	Date out of service Date out of service	Notes notes
K-2	K-102
K-3	K-103
K-4	K-104
K-5	K-105
K-6	K-106
K-7	K-107
K-8	K-108
K-9	K-109
K-10	K-110
K-11	K-111
K-12	K-112
K-13	K-113
K-14			03-12-1939		Collision with K-16. Written off.
K-15	K-115
K-16			03-12-1939		Collision with K-14. Written off
K-17	K-117
K-18			08-08-1939		Collision with K-19. Written off
K-19			08-08-1939		Collision with K-18. Written off
K-20	K-120
K-21	K-121
K-22	K-122
K-23	K-123
K-24	K-124
K-25	K-125
K-26	K-126
K-27	K-127
K-28	K-128
K-29	K-129
K-30	K-130
K-31	K-131
K-32	K-132
K-33	K-133
K-34	K-134
K-35	K-135
K-36	K-136
K-37	K-137
K-38	K-138
K-39	K-139
K-40	K-140
K-41	K-141
K-42	K-142
K-43	K-143
K-44	K-144
K-45	K-145

 

1/72nd Scale

Kits

• Dekno
  • Kit E-2100: A short run kit of the early version of the FK.51.
• Special Hobby
  • Kit 72048: A short run injection moulded kit for the late version with Dutch decals for a LVA and RNlNAS aircraft (with resin cowling).
  • Kit 72051: A short run injection moulded kit for the late version with Dutch decals for a NEIAF aircraft (with resin cowling).
• Azur
  • Kit AZ064: A short run injection model of the Spanish version.

 

 

Modelling add-on

• Steelwork
  • Set 7209: Correct Wheels Koolhoven FK51 (for MPM/Special Hobby)

Decals

• FlevoDecals
  
  • Set FD72-012: ML-KNIL 1939-1942

1/48th Scale

Kits

• --
  • Kit --: --

Modelling add-on

• --
  • Set --: --

Decals

• --
  • Set --: --

 

 .

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

Koolhoven FK.51 LVA

 

Koolhoven FK.51 RNlNAS

 

Koolhoven FK.51 NEIAF

 

Literature.

Van Brik tot Starfighter	H. Hooftman		1965	La Rivière en Voorhoeve - Zwolle
Zestig jaar Marineluchtvaartdienst in Beeld.	Hugo Hooftman	Pag. 52 - 53	1977	Uitgever: Europese Bibliotheek, Zaltbommel
Nederlandse Militaire Luchtvaart in Beeld. deel 1.	Hugo Hooftman	Pag. 132 - 135	1977	Uitgever: Europese Bibliotheek, Zaltbommel
Militaire Luchtvaart in Nederlandsch-Indië in beeld. Deel 1	Hugo Hooftman	Pag. 133 - 136	1978	Uitgever: Europese Bibliotheek, Zaltbommel
Nederlandse Marinevliegtuigen	Thijs Postma & Nico Geldhof	Pag. 18	1978	Uitgever: Omniboek, 's Gravenhage
Nederlandse Vliegtuig-Encyclopedie No. 6 Koolhoven FK.51	Hugo Hooftman	Pag.	1978	COCKPIT-uitgeverij, Bennekom
AVIA: 40e jaargang nummer 9: De Koolhoven FK.51, het enige Koolhoventype van de MLD	Nico Geldhof	Pag. 391 - 392	1981	Uitgevers Wyt, Rotterdam
Koolhoven Nederlandse vliegtuigbouwer in de schaduw van Fokker	Theo Wesselink & Thijs Postma	Pag. 93 - 104	1981	Uitgever: Unieboek b.v., Houten
De Nederlandse Vliegtuigen: Alle vliegtuigen ooit in Nederland ontworpen en gebouwd	Theo Wesselink & Thijs Postma	Pag. 94	1982	Uitgever: Romen Luchtvaart, Haarlem
Squadrons van de Koninklijke Luchtmacht	Willem Helfferich	Pag. 15	1983	Uitgever: Unieboek b.v., Houten
40 Jaar luchtvaart in Indië	Gerard Casius & Thijs Postma	Pag. 51	1986	Uitgeverij De Alk, Alkmaar
KLu Vliegtuigen: De vliegtuigen van de Koninklijke Luchtmacht vanaf 1913	Wim Schoenmaker & Thijs Postma	Pag. 73	1987	Uitgeverij De Alk, Alkmaar
Van Aviolanda tot Fokker	Wijngaarden, P. van	Pag. 45 - 47	1987	Uitgever: De Klaroen, Alblasserdam
Van Luchtvaartafdeling tot Koninklijke Luchtmacht: 75 jaar Militaire Luchtvaart in Nederland	Koos van de Berg	Pag. 26	1988	Uitgever: Rebo Produkties, Sassenheim
Camouflage en Kentekens	J.Greuter e.a.		1997	Bonneville – Bergen (NH)

 

Websites.

• AlexDenOuden.nl: Koolhoven FK.51
• Go2War2.nl:Koolhoven FK.51
• Wikipedia Nl: Koolhoven FK.51
• B.Hummel: FK51
• LVA-40.nl: Koolhoven FK.51

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