Fokker D.XXI

Fokker D.XXI aircraft in the Finnish air force during World War II

Fokker D.XXI aircraft in the Finnish air force during World War II

The Fokker D.XXI (or D.21) was a small fighter. Fokker was developed in the 30s of the 20th century.


The D.XXI was intended for the interception of enemy aircraft. The device was designed for the ML-KNIL, however opted for American appliances. Then the D.XXI was purchased by the LVA, the Aviation Department of the Dutch army, the first specimens in 1938 at the service. These were specimens with a more powerful engine, in which Finnish specifications were developed. The D.XXI was the original lighter engine delivered toDenmarkand the heavier engine toFinland.Denmarkhas built ten copies of license.Finlandalso built the type of license and used it successfully during the Winter War. After the Winter WarFinlandresumed production, with a different engine. AlthoughSpainacquired the licensing rights (Hispano Aviacion), Spanish aircraft never entered service. There were 25 and 50 hulls built wings. Only one copy was test flown by a Russian M-25 engine. The factory then fell into Nationalist hands and the Breeders were never completed. Parts were later used for the construction of Hispano 42 trainers.

Copies in Museums

In 1988 Fokker built a copy of theMilitaryAviationMuseumin Soesterberg. In theCentralFinnishAviationMuseum(Keski-Suomen ilmailumuseossa) in Tikkakoski is a copy that around 1989 is composed of different parts of Finland D.XXI ‘s. The body belonged to the FR-110, this specimen obtained during the Winter War the most wins.


The hull was constructed with metal pipes. The front part was covered with metal and the rear part with linen. The wings were covered with wood. The chassis was not retractable and consisted of a pair of struts, the wheels were quite streamlined caps fitted.

Deployment inFinland

At the start of the Winter War,Finlandhad 36 aircraft built and put into service, all with Mercury VIII engine. In addition to the Bulldog obsolete biplanes, were the only Finnish fighters. The D.XXI complied perfectly with the bet against bombers but struggled with the agile I-15, I-153 and I-16 fighters. The Finnish Air Force placed therefore to the fight against bombers. And with success, because the D.XXI reached 119 victories against only a few losses. From February 1940, just before the end of the Winter War, other fighters began to arrive and the Fokker as the main fighter repaid. Well had already begun the construction of a new series of 50 aircraft with a Twin Wasp Junior engine. This was basically as powerful as the Mercury, but had a higher weight and met fellow less well. At the resumption of the war in 1941, the Fokker still mainly used in ground attacks. Specimens that survived the war flew until 1948. Nowadays in Finland D.XXI an icon for the unequal struggle of 1939/1940.

Deployment inDenmark

On 9 April 1940,Denmarkin one day occupied by Nazi Germany. The Danish Air Force was the air base of Værløse largely destroyed on the ground by Me-110 fighters and offered no further resistance more. The D.XXI was not deployed. Almost all aircraft were repaired by the Danish Air Force. The Danish forces were formally exist although they are no longer allowed to operate. In 1942 the equipment still seized byGermanyand the devices that fell into German hands by the Luftwaffe were used as target tug.

Deployment in theNetherlands

On 10 May 1940, the Netherlandswas attacked. In the LVA were patrols often flown with 3 boxes. Only the patrol leader had a radio on board, and when he received orders from the ground he had his wing men with hand signals instruct.
The low speed, largely through the fixed base and the low power causes, was the hunter at a disadvantage compared to the Messerschmitt Bf 109. The unit was in favor by the greater maneuverability and small turning circle. A mounted gun was a lack in the armament.

In his book War Flyer Orange Bob van der Stok described his experiences with the D.XXI during 10 to 14 May 1940. Although the Fokker D.XXI it together with the other operational type, Fokker GI, reasonably made against modern fighters and bombers of the Luftwaffe, gave the quantitative and the qualitative superiority of the enemy ultimately decisive. Some copies of the D.XXI were captured by the Germans. One was in the “BeuteflugzeugeMuseum” inBerlin exhibited to this museum in1942 in a bombing destroyed.

Commitment in theDutch East Indies

The prototype of the D.XXI, registration FD-322, was built for the Military Aviation of the Royal Netherlands Indies Army (KNIL-ML). Ultimately, the prototype there also arrived, although ML-KNIL no order for D.XXI set. According to eyewitnesses, it was in July 1940 one of the fighters of the ML-KNIL that were provided with the new camouflage pattern. The unit would be registered until March 1942 and was probably destroyed on the ground at the airport Andir. Combat operations are not known.


  • D.XXI-1
  • 2 copies for Denmark temporarily a 645 hp Mercury VIS engine and two20 mmMadsen cannon in the wings, Danish registration numbers J-41 and J-42, Fokker construction numbers 554 and 555. The engine was later replaced by a Mercury VIII. The Danes (Haerens Flyvertroppernes Vaerkstader) built another 10 similar aircraft under license, J-43 t / m J-52.
  • D.XXI-2
  • 43 copies for the Dutch (Nos. 212-247) and Finnish Air Force (FR-76 t / m FR-82) equipped with a 830 hp Bristol Mercury VIII.
  • D.XXI-3
  • 38 inFinlandby Valtion Lentokonetehadas built D.XXI equipped with a 830 hp PZL / Mercury VIII or Tampella / Mercury VIII engine (FR-83 t / m FR-120).
  • D.XXI-4
  • 50 inFinlandby Valtion Lentokonetehadas built D.XXI equipped with a 830 hp Pratt & Whitney R-1535 Twin Wasp Junior engine-SB4, other weapons, a larger tail fin and another cockpit window.
  • D.XXI-5
  • 5 copies with a 920 hp Bristol Pegasus X engine.


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