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Typenumber D21
Type of aircraft
Country The Netherlands
Date first flight 27 March 1936
Wingspan 36 ft, 1 inch / 11 m.
Lenght (Mercury) 26 ft, 11 inch / 8.22 m,

(P&W R-1535) 26 ft, 3 inch / 8 m.

Wing area 16.2 sq. m
Crew 1
Enginetype One Bristol Mercury VIII nine-cylinder radial.
power (HP or LBS)
830 hp
1450 kg
Takeoff weight 2050 kg
Armament 4x7.9 mm Browning M-36 machine guns
Speed (Mercury VIII) 286 Mph / 480 Km/h. (P&W R-1535) 272 Mph / 439 km/h.
Climb (to 9842 ft / 3000 m) (Mercury) 3 – 5 min
(P&W R-1535) 4 – 5 min.
Ceiling (Mercury) 36090 ft / 11000 m.R-1535) 32000 ft / 9750 m.
Range (Mercury) 590 miles / 950 km, (P&W R-1535) 559 miles / 900 km.
Users Denmark, Finland, and the Netherlands.

D.21 in the LuVA

In 1938 kwam de D-21 bij de LuVA in dienst. Het was een ééndekker met vier vleugelmitrailleurs, die paarsgewijs links en rechts in de vleugel waren gemonteerd.

De D-21 had in vergelijking met zijn Duitse tegenstanders een lagere snelheid, maar was wel erg wendbaar. Een nadeel was het vrijwel ontbreken van boordradio's bij de D-21s van de LuVA. Slechts drie D-21s waren hiermee uitgerust, de nummers 212, 219, en 221. Ook kon het landingsgestel niet worden ingeklapt.

De 1e en 2e JaVA van De Kooy en Schiphol werden op 11 mei op het vliegveld Buiksloot verenigd tot een nieuwe eenheid. De Jagerafdeling op Ypenburg verloor door zware Duitse tegenstand op één na al haar toestellen.

De camouflagekleuren waren camouflagebruin, -beige en -groen.
De door Fokker aan Finland geleverde D-21's bewezen hun diensten in de Fins-Russische oorlog van 1939-1940.


Fokker leverde in totaal 36 D-21s aan de LuVA. Ze hadden de nummers 212 t/m 247.

De 212, 215-217, 222, 227-228, 246-247 vormden de 1e JaVA van het 2e Luchtvaartregiment op Ypenburg.
De 213, 224, 225, 229, 232, 235-236, 238-239, 243 en 245 vormden de 2e JaVA op Schiphol.

De 214, 218-219, 221, 223, 234, 237, 240-242 en 244 vormden de 1e JaVA op De Kooy.
De 220 was in reparatie bij Fokker (90% gereed)

De 226 en 232 stonden bij de Jachtvliegschool Texel op 'De Vlijt'.
De 230 was al afgeschreven. Ze stortte op 22 november 1939 neer bij Hillegersberg, de vlieger kwam om.


5 Fokker D-21s gingen op de grond verloren.
11 Fokker D-21s gingen door gevechtshandelingen verloren.
4 Fokker D-21s gingen door een andere oorzaak verloren.



Fokker D.21

Fokker factory in 1936. Wings of the D.21 fighter in the front and the large fusulage of a T.5 bomber in the back of the hangar

Fokker D.21 Prototype

Fokker D.21 prototype FD-332 at Schipol airfield 1936 during Wool Tuft tests. Notice the white dots on the rear fuselage surface. The strings were used to verify the airflow over the fuselage and tail. Rudder flutter had been experienced and so tin weights had to be installed. The canopy has been removed for tests

Dr. Schatzki (left) with Meinecke (next to him) in front of the prototype of the D.21

Fokker D.21 cockpit

Fokker D.21 cockpit

Fokker D.21 with Bristol Mercury engine which turned out to give better performance for the Fokker than the Twin Wasp engine

Fokkers D.21 in service of the Finnish Airforce

Fokker D.21 with Dutch neutrality markings on its site



In the second half of the 1930’s, any sound warplane that was generally available could be sure of attracting widespread interest.

The Fokker D.21. came from a company with a great reputation all over the world, and though it was designed - by Ir. E. Schatzki in 1935 – purely to meet the requirements of the Netherlands East Indies Army Air Service, it became the leading fighter of three major European nations and was planned as a standard type by a fourth.

This was as well for Fokker, because the plans of the original customer were changed and a contract was never signed.

Yet the little fighter was all one could expect: neat, tough and highly maneuverable, with good performance and heavy armament. It marked the transition between the fabric-covered biplane and the stressed-skin monoplane.

The wing was wood, with bakelite/ ply skin. The fuselage was welded steel tube, with detachable metal panels back to the cockpit and fabric on the rear fuselage and tail. The landing gear was fixed.

The prototype flew at Welschap (today: Eindhoven Airport, both civil and military aviation) on a Mercury VIS engine, and in May 1937 the home government ordered 36 aircraft with a more powerful Mercury, supplied from Bristol.

There were many Fokker projects for developed D.21.’s with retractable landing gear and other engines, but the production aircraft was generally similar to the prototype.

In the seventh prototype (No. 217) test pilot H. Leegstra set  a Dutch height record at 37.250 ft / 11.400 m.

Meanwhile, production of a modified version was getting under way for Finland, which bought seven aircraft with a manufacturing license.

Denmark followed with an order for three and a manufacturing

Fokker D.21 J-47, C Arvo Karin

Fokker D.21

Fokker D.21 at Soesterberg Military  Airmuseum in 2000

Fokker D.21

Fokker D.21

license and a fourth to adopt the D.21. was Republican Spain.

The latter set up a new plant and was about to start accepting deliveries, when the area was overrun by nationalist forces.

The VL (Finnish State factory) delivered 38 in 1939- 1939 and all of them participated very successfully in air battles against the Soviet forces from the start of the Soviet invasion, but all the Finnish-built Mercuries were needed for Blenheims.

The Finnish D.21. was redesigned to take the heavier but less powerful Twin Wasp Junior, 55 of this type being built, one of these having a retractable landing gear.

The Danish Royal Army Aircraft Factory gradually delivered ten aircraft with low-rated Mercury engines and two cannons, eight being taken over during the German Invasion in March 1940.

Finally, on 10 May 1940, the 29 combat ready aircraft in Holland fought round the clock until their ammunition ran out the third day.
The Dutch gave up fighting on 14 May 1940.

German attack on the Netherlands

History of the Fokker D.21. during the German attack on the Netherlands, 10 to 14 May 1940.

The 28 operational Fokker’s are devided in 1e JAVA (DE KOOY airfield, near Den Helder), 2nd JAVA (SCHIPHOL, near Amsterdam) and the 1st Division Fighter Group Field Army (YPENBURG Airpark, near Rotterdam).

At De Kooy are 11 D.21.’s.

They are devided in in three sections of 3 and one section of 2 aircraft. Only the aircraft of the commanders are equipped with radio’s, so there is no communication possible between the pilots in the aircraft.
About 04.00 h in the morning, all D.21.i’s of 1e JAVA ar ordered to scramble.

The 223 is chasing a Heinkel He-111 bomber. Nearby “Wassenaarse Slag”, the 213 is shot down by other He-111’s.

The 244 is chasing a Junkers Ju-88. The Junkers is shot down nearby “Noordwijkerhout”. After a stopover at SCHIPHOL, the aircraft returns to De Kooy.
The other planes are flying CAP’s over De Kooy, Texel, the Afsluitdijk en Bergen.

After a while they return to De Kooy to refuel. When the first six aircraft take off again at 04.45 h and the last three are preparing for landing, there is an attack by nine German Messerschmidt Bf-109 aircraft.


The 241 is shot and set on fire during the landing. The 219 is aborting the landing and the 218 is taking off again. There is a bitter fight between seven Dutch aircraft and these nine German Bf-109’s.

The 219 is destroying the engine of one Bf-109, forcing it to make a crash landing. The 234 and the 242 both gun down a Bf-109. The 221 is damaging one of the Bf-109’s so badly, that it is going down in the “Wieringermeer” lake.

The 218 and the 234 arechasing two other Germans and force them to disengage. One of these two Bf-109’s crash lands on one of the German North Sea Islands. The remaining nine D-XXI aircraft all land at De Kooy, all with battle damage, five of them have serious battle damage.

The 214 and the 233 are destroyed shortly after that due to shelling by Bf-109 and Me-110 aircraft.

After four D-XXI’s are repaired, there is a bombardment with firebombs by Me-110 aircraft. The 234 is lost in this bombardment while six others are seriously damaged. The remainder of 1e JAVA is being joined together with what is left of the 2nd JAVA (SCHIPHOL) at the auxiliary airfieldBUIKSLOOT nearby Tuindorp-Oostzaan.  

2nd JAVA is posted at SCHIPHOL and has nine operational D-XXI aircraft. They take off during a bombardment of the airfield at 03.58 h.

Crash landings

The 245 crash lands nearby Zwaagdijk and is lost. The 225 shoots down a Junkers JU-88 and evades to RUIGENHOEK, lands there at 04.15 h. just to discover that people over there are not aware of the fact that there is a war situation.

The 224 is attacking Heinkel He-111 bombers and evades to Ruigenhoek, together with the 229. Later on the 213 and the 239 are being sent to Ruigenhoek, after landing at Schiphol, when the first attack on Schiphol is over.

From Ruigenhoek, five D-XXI aircraft are being sent on patrol over the province of ZUID-HOLLAND (South Holland). During this mission, they continuously attack a Junkers Ju-52 transport plane. This Ju-52 finally crash lands near “Stolwijk”.

Near “Oudekerk aan de Yssel” the 229 is being attacked and crashes in the “Hollandse Yssel” river. Two other D-XXI’s land at Schiphol, the other aircraft at Ruigenhoek. From there, they take off for a patrol mission to “Katwijk”, where they strafe German aircraft that have landed on the beach. After that they return to Schiphol.

At the end of the first morning the six aircraft are available again. A D-XXI that evaded from Ypenburg airfield comes in for a landing.

Three Fokker T-V bombers are flying to WAALHAVEN airfield, protected by six D-XXI’s. At Waalhaven they are spotted by nine Me-109 aircraft en an entangled battle is developing.

The 238 is being shot down. The 236 is shooting while diving at a landed Junkers Ju-52, hits a Me-109 that crashes near “Oud Beijerland” and returns intact to Schiphol.

There it appears that the 239 is damaged beyond repair. The remaining six aircraft will be regrouped with the remainder of 1e JAVA at the auxiliary airfield Buiksloot.


1e and 2nd JAVA are now operating together and they have eight Fokker D-XXI aircraft available.

- On 11 May three D-XXI’s will escort two Fokker C-V biplanes to “Ede / Arnhem”, but there is a misunderstanding during this mission and the D-XXI’s return to Buiksloot. Three other D-XXI’s, being repaired at De Kooy airfield, land there.

Three other D-XXI aircraft escort Fokker T-V bombers on a mission to Rotterdam to destroy the “Maasbrug” (bridge over the river “Maas). All aircraft return intact.

Again three D-XXI’s are escorting two C-V biplanes to “Ede / Arnhem” and these planes too return intact.

The first effort on bombing the Maasbrug failed, so a second mission is planned. Again the T-V bombers are being escorted by three D-XXI’s. They meet twelve Messerschmidt Me-110 aircraft. The 242 escapes and lands at Buiksloot. The pilot of the 225 decides to use his parachute.
He has already released his canopy, this canopy hits the propeller of a Me-110. He flies through a cloud and with his machine guns he hits a second Me-110. After that he is shot down himself. His aircraft ends up in the surroundings of “Leiden” city.

The 213 lures away six Me-110’s from the T-V bombers. One of the enemy planes is shot down over “Moerkapelle”, probably a second one. However, the pilot of the 213 is seriously injured and lands on the road between Den Haag (the Hague) and Utrecht, near “Zevenhuizen”.

Nine Fokker D-XXI aircraft are left at Buiksloot airfield. In the afternoon, two of the planes are going on a recce mission over western Amsterdam. It is believed that paratroopers have landed there but they are not spotted.

German attack

On 12 May three D-XXI’s escort two C-V biplanes to Arnhem. On the way to Arnhem they are being shot at by friendly forces. The 218 comes in for a landing, overturnsand is damaged beyond repair.

Three D-XXI aircraft accompany four C-V biplanes to Rotterdam and Delft, where German forces have to be attacked. The mission is not developing as planned, but the aircraft return safely to Buiksloot airfield. There, two repaired D-XXI’s have also arrived from De Kooy airfield.

In the afternoon, six D-XXI’s are ordered to escort Fokker C-X biplanes on a bombing mission to Waalhaven airport and Feyenoord Shipyard. With their machine guns, the D-XXI’s also have to set enemy planes on fire, that have landed at Waalhaven airport. The mission is a great success and all planes return safely. Later that afternoon another D-XXI is escorting a T-V bomber from Schiphol to “Wonsstelling” (the frontline at Wonsstelling). Near “Medemblik” they are being stopped by five German planes and the Dutch aircraft return to base.

On 13 May four Fokker C-X biplanes are being escorted by five D-XXI’s for a mission in the “Wageningen” region. Friendly forces are shooting on the aircraft again and again.Late in the morning the bombing mission on the “Grebbenberg” line is repeated by four C-X’s escorted by five D-XXI’s.

During the night from 13 to 14 May, an order comes in to leave and destroy Buiksloot auxiliary airfield, all aircraft and personnel are ordered to Schiphol. But first five D-XXI aircraft have to cover the withdrawal of the forces of the Field Army, who have evacuated the Grebbenberg Line.


For a long time they are being shot at, again by friendly forces.

The 236 is being hit and crash lands near “Vleuten”. The remaining aircraft land at Schiphol, as ordered.

As a result of the many repairs, the material and equipment is wearing out very fast, the power of the Germans is too much. A list ist being put together with names of possible “Engelandvaarders”, people that evacuate to Great Britain.

However, five D-XXI’s still go on a patrol mission. They encounter no enemy aircraft and return to base safely.
The aircraft are being prepared for a next mission but there is almost no ammunition left.

The remaining nine D-XXI see no action any more. At 19.00 h that 14th May, the Dutch surrender and the submission is being signed. Crossing to England is strictly forbidden, as being against submission rules.

At YPENBURG Airpark, nine D-XXI aircraft of the 1e Afdeling Jachtgroep Veldleger (1st Division Fighter Group Field Army) are detached.

When German aircraft are approaching at 04.00 h, eight D-XXI aircraft that are battle-ready, take off.
They fly in two formations of three and one of two aircraft.

The formations however, are being driven apart by the Germans and than the D-XXI pilots engage the German aircraft by themselves.

The 222 is engaging but has problems with jamming guns. The aircraft heads west but is attacked by German planes and crash lands near “Monster”.

Jamming guns

The 216 is engaging too and shoots down a Ju-52 near Den Haag (the Hague). He then runs out of fuel and ammunition and lands at Ruigenhoek. There is no pressed air available for his machine guns.

With his machine gunes damaged beyond repair, this D-XXI takes off again, but near VALKENBURG airfield, the aircraft is being attacked by five Me-110’s. The aircraft crashes near “Den Deyl”.

The 247 shoots down a enemy fighter and has to land for fuel and ammunition on the upset Ypenburg airfield. Shortly after that the 247 is being attacked by German fighters and catches fire.


On Ypenburg airfield, the backward unarmed D-XXI is a prey for German machine guns.

The 246 has four jamming guns. The pilot lands his plane and takes off again in the 215. Later on he lands the undamaged airplane on the beach at “Kijkduin”, where the aircraft is destroyed by German fighters.

The 212 is taking part in the battle until the aircraft runs out of fuel and then heads for Schiphol. Near “De Kaag” this D-XXI shoots down a Dornier D0-17, but during this attack his engine receives damage.

The D-XXI glides down to Schiphol, where it lands. There the 212 is attached to 2nd JAVA.

All the luck

During take off, the repaired 246 has all the luck of the world, when a bomb misses the plane with a few meters. During an air battle near Delft, the pilot is injured and has to leave his D-XXI. The aircraft crashes near “Pijnacker”

After shooting down a German plane, the 228 lands at OCKENBURG Airfield, out of fuel and ammunition.


The aircraft is being damaged during a German attack.

The 217 is engaging in air battles and then also lands at Ockenburg airfield. This aircraft too is unable to take off again.
Due to shortage of fuel and ammunition the 1e Afdeling Jachtgroep Veldleger is not existing anymore within 1½ hour of battle.


At the end of the fighting, the Militaire Luchtvaartafdeling (Military Aviation) had lost 20 officers, 25 Non Commissioned Officers and 30 corporals and airmen.

On 18 May 1940 the “Wapen der Militaire Luchtvaart” (the Military Aviation) is awarded the “Militaire Willemsorde 4e klasse” (Military Williams medal 4th class) by the supreme commander of the Army and the Navy.


The medal is awarded for “MOED, BELEID en TROUW” (Courage, Policy and Loyalty).

Although the D-XXI was not as heavy armed as his German opponents, the aircraft outclassed the German Messerschmidt Me-110 in maneuverability and in climbing.