Fokker D.XXI.

NV Fokker Vliegtuigenfabriek, the Netherlands. Aircraft license-built by: 
Type:
	Single-seat fighter
Engine:
	Dutch: 		One 830 hp Bristol Mercury VIII nine-cylinder radial.
	Danish: 	One 645 hp Mercury VIS.
	Finnish:	One 825 hp Pratt & Whitney R-1535-SB4-G Twin Wasp Junior 14-cyl-inder two-row radial.
Dimensions:
	Span:		36 ft, 1 inch / 11 m.	
	Length:		(Mercury) 26 ft, 11 inch / 8.22 m,	(P&W R-1535) 26 ft, 3 inch / 8 m.
	Height:		9 ft, 8 inch / 2.94 m.
Weights:
	Empty:		(Mercury) 3180 lb / 1422 kg, (P&W R-1535) 3380 lb / 1534 kg.
	Loaded:		(Mercury) 4519 lb / 2050 kg, (P&W R-1535) 4820 lb / 2186 kg.
Performance:
	Max. 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.
	S. Ceiling:	(Mercury) 36090 ft / 11000 m, (P&W R-1535) 32000 ft / 9750 m.
	Range:		(Mercury) 590 miles / 950 km, (P&W R-1535) 559 miles / 900 km.
Armament:
	Dutch:		Four 7.9 mm FN-Browning machine guns, two in the fuselage and two in the wings.
	Danish:		Two Madsen 7.9 mm machine guns in the wings and two Madsen 20mm cannons in underwing blisters.
	Finnish:	Four 7.7 mm machine guns in outer wings.

History:First flight: 27 March 1936.

Delivery: Users: Denmark, Finland, and the Netherlands.

Development:
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-XXI 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. 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-XXI’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 license and a fourth to adopt the D-XXI 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-XXI 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…

THE DUTCH AIR FORCE IN MAY 1940

The Dutch Air Force at that time was devided in three groups;
  1. e Luchtvaartregiment (1st Aviation Regiment); Luchtverdediging (Air Defense).
  2. e Luchtvaartregiment (2nd Aviation Regiment); Legervliegdienst (Army Air Service).
  3. e Luchtvaartregiment (3rd Aviation Regiment); Opleidingen, hulpdiensen en depot(Training, Support and Depots).
All three regiments had several squadrons and used several types of aircraft.

In the 1st Regiment (Air Defense), there were three units (groep)using the D-XXI: In the 2nd Regiment (Army Air Service) was only one unit using the D-XXI: JACHTGROEP VELDLEGER (Fighter Group Field Army): In the 3rd Regiment (Training, Support and Depots) was a Flight school for advanced pilots that had to train on fighters (and also aircraft with more than one engine). One unit in this school was called JACHTVLIEGSCHOOL (Fighter School).
This school used several types of aircraft, two of them were Fokker D-XXI.
The unit was based at Texel (one of the Netherlands North Sea Islands).

Totally the Dutch Air Force had 36 Fokker D-XXI aircraft, registrations were 212 to 247 in white numbers on both sides of the fuselage. Unfortunately, when the war started, only 28 D-XXI aircraft were operational, not one survived the war.

At the present day, there is only one Fokker D-XXI present in the Netherlands, this aicraft is displayed in the Militaire Luchtvaart Museum (Military Aviation Museum) at Soesterberg Airbase. It is a former Finnish aircraft, painted in Dutch markings.

Following below is a brief history of the actions of the Fokker D-XXI during the German attack on the Netherlands.

THE EXHAUSTING ACTIONS OF THE FOKKER D-XXI.

History of the Fokker D-XXI 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-XXI’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-XXI’s of 1e JAVA ar ordered to scramble. 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. 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. 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, overturns and is damaged beyond repair. 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. 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. 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.

Sources on the above information:

Technical information and info on development is from: Numbers on the Dutch Air Force in 1940 are taken from: All information on this page has been donated by: Johan “VIPER” Lemmers