Fokker D.XXI
The Fokker D.XXI was a Dutch single-seat fighter designed by Fokker in 1935 for the Royal Netherlands East Indies Army Air Force: an inexpensive, rugged monoplane of welded steel tube, fabric and wood with a fixed undercarriage and a Bristol Mercury radial. The Netherlands ordered 36, and the type was also built under licence in Finland — its largest operator — and in Denmark. Already obsolescent in 1939, it fought in Finnish hands through the Winter War and the Continuation War, in which the Finnish Air Force credited it with 191 victories, and it was the only relatively modern fighter the Netherlands could field against the German invasion of May 1940. Finland retired the last examples in 1949; one complete original, FR-110, survives at the Finnish Air Force Museum, and a faithful replica flies in the Netherlands.
Why It Mattered
The Fokker D.XXI was the last fighter Anthony Fokker's company put into production: a simple, inexpensive monoplane designed in 1935 for the Royal Netherlands East Indies Army Air Force. It was already obsolescent when Finland went to war with the Soviet Union in 1939. Yet the Finnish Air Force credited it with 191 victories in the type across two wars against the Soviet Union, and for the Netherlands it was the only relatively modern fighter available when Germany invaded in May 1940.
Design Notes
Fokker's design team, led by Erich Schatzki, answered the East Indies requirement with an inexpensive, rugged and compact fighter aircraft. The fuselage was a welded steel tube structure, largely covered by fabric, and the wing was wooden, composed of two box spars attached to ribs made of plywood. The undercarriage was fixed, with spatted cantilever legs, and the cockpit was fully enclosed by a plexiglas hood. Production aircraft were powered by a Bristol Mercury VIII radial producing 830 horsepower; Dutch aircraft were armed with four 7.92 mm FN-Browning machine guns in the wings, Finnish aircraft with four 7.7 mm Vickers guns. The prototype, FD-322, made its maiden flight at Welschap airfield, Eindhoven, on 27 March 1936.
Operational History
Fokker's Dutch order was for 36 aircraft, the final one delivered on 8 September 1939. Finland, the first export customer, ordered an initial batch of seven aircraft and negotiated a manufacturing licence, under which its State Aircraft Factory built 90 more in four batches. Denmark ordered two aircraft and built ten under licence; in Spain, 50 fuselages were reportedly manufactured for the Republic before the plant was overrun by Nationalist forces and no Spanish-built aircraft was completed. In all, 148 D.XXIs were built. Finland was the first air force to fly the type in combat: it had 41 D.XXIs in service when the Winter War began, and on 1 December 1939 a Finnish D.XXI shot down a Soviet Tupolev SB, the type's first aerial victory. The Finnish Air Force credited the type with 191 victories across both wars; its highest-scoring pilot, Jorma Sarvanto, was credited with 12 5/6 victories in the type. In the Continuation War of 1941–1944 it was used mainly for reconnaissance and, later, as an advanced trainer. The Dutch aircraft had five days of war: 28 were serviceable on 10 May 1940, their pilots were credited with 16 victories, and when news of the capitulation reached them on 14 May the remaining aircraft were destroyed to keep them from German hands. Finland flew its D.XXIs until 1949.
Afterlife
Only one complete original D.XXI is known to survive: FR-110, on display at the Finnish Air Force Museum at Tikkakoski. The museum credits FR-110 with 9½ victories, the highest tally of any D.XXI; other accounts credit it with ten. In the Netherlands, the forward fuselage of a Dutch D.XXI reportedly shot down near Nieuwkoop in May 1940 is displayed at a small museum at Aalsmeerderbrug, and a full-size replica stands at the Nationaal Militair Museum at Soesterberg. A faithful replica built by restorer Jack van Egmond to original Fokker specifications, using some original parts, first flew on 23 May 2022 from Hoogeveen, and has since completed its test flight programme and has been flying without issues.