On 6 January 1940, a formation of Soviet Ilyushin DB-3 bombers flew in across the Gulf of Finland. Near Utti, seven of them met one Finnish lieutenant in a Dutch fighter with fixed landing gear and four rifle-calibre machine guns.

Jorma Sarvanto shot down six of them in about four minutes. A seventh fell to his squadron mate Per-Erik Sovelius before it could reach home. Newspapers across the West called it a world record, and the fighter that made it possible became a national legend: the Fokker D.XXI.

A cheap fighter from Amsterdam

Fokker designed the D.XXI in the mid-1930s as an inexpensive, rugged and compact fighter, first for the Dutch Army Aviation Group. The prototype flew at Eindhoven on 27 March 1936. It was a low-wing monoplane with an enclosed cockpit, a Bristol Mercury radial engine and a fixed, spatted undercarriage that already looked a little old-fashioned when it rolled out.

Finland liked it anyway. In 1937 the government ordered seven from Fokker and bought a licence, and the State Aircraft Factory at Tampere began building more. When the Soviet Union invaded on 30 November 1939, the Finnish Air Force had about 40 Mercury-engined D.XXIs, the backbone of its fighter force.

The Dutch had their own war to fight. When Germany invaded the Netherlands on 10 May 1940, 28 Dutch D.XXIs were serviceable, and on the first day six of them escorted Fokker T.V bombers against the Meuse bridges and tangled with Bf 109. Denmark had built ten under licence before the German invasion in April 1940. In both countries the fight was brief. Only in Finland did the Fokker get a long war.

On paper the odds were absurd. Air Force Magazine historian Richard Hallion counts 2,318 Soviet aircraft against 114 Finnish ones. The Fokker had a top speed of around 460 km/h (286 mph) and only four 7.92 mm machine guns. But its rugged radial engine and fixed undercarriage suited Finnish conditions, the gear took to skis and rough snowy strips, and its pilots were exceptionally well trained.

A fighter squadron that trained for this

Most of the Fokkers flew with Fighter Squadron 24, LeLv 24. Its leaders had drilled the pilots hard in gunnery and tactics, and had taught them to avoid turning fights with nimble Soviet biplanes. Their target was the bombers. The D.XXI scored its first victory on 1 December 1939, the second day of the war, shooting down a Tupolev SB.

Ed Nash’s Military Matters on the Fokker D.XXI, the Dutch fighter that served Finland far longer than anyone expected.

The pilots had a rhythm by Christmas. According to Hallion, LeLv 24 shot down 12 bombers on 19 December and ended 1939 having destroyed 54 aircraft for the loss of one Fokker. Among the young pilots was Ilmari Juutilainen, who would become Finland’s top ace later in the Second World War.

Six bombers in four minutes

Sarvanto was 27 that winter. Born in Turku, he had graduated top of his military academy class in 1937 and moved to fighters at his own request. In LeLv 24’s firing tests he averaged a 92 per cent hit rate. His first two victories came on 23 December 1939.

On 6 January, Finnish signals intelligence warned that a raid was coming. Seventeen DB-3s flew in from Estonia. Near Utti, Sovelius met the second wave first and shot one bomber down. Sarvanto attacked the remaining seven on his own and brought down six of them in about four minutes. Sovelius caught the last one as it crossed the coast.

The press photographed him holding a large sheet of aluminium with a big “5” on it, a piece of one of his victims. He ended the Winter War as Finland’s top-scoring ace with 13 victories, almost all of them, 12 5/6 in Finnish reckoning, scored in the Fokker. He later added four more in Brewster Buffaloes and finished his career commanding the air force flying school at Kauhava.

Real Time History’s documentary on the Soviet invasion of Finland and the Winter War of 1939–40.

Outnumbered, then outclassed

January was the Fokker’s best month. Hallion records 34 Soviet aircraft shot down by Finnish Fokkers in January 1940. But Soviet fighter escorts grew stronger, the pilots flew up to eight sorties a day, and fatigue caused accidents. By the end of January, LeLv 24 had only 28 serviceable Fokkers left.

The worst day came on 29 February, when a large force of Polikarpov fighters surprised Fokkers and Gladiators over Immola and shot down seven Finnish aircraft. Two weeks later, on 13 March 1940, the Winter War ended with Finland ceding territory but keeping its independence.

Twelve D.XXIs were lost in the war, six of them in accidents rather than combat. Against that, LeLv 24 pilots claimed 120 aerial victories. Hallion puts the Fokker’s kill ratio at 16 to one.

The Fokker’s long afterlife

The D.XXI kept flying for Finland through the Continuation War of 1941–1944, including a new batch fitted with American Pratt & Whitney Twin Wasp Junior engines obtained via Sweden. Finland kept the type in service until 1949.

The highest-scoring D.XXI, FR-110, survived with ten victories to its name, the aircraft flown by Lieutenant Viktor Pyötsiä in the Winter War. It is displayed today at the Aviation Museum of Central Finland near Jyväskylä, a slightly old-fashioned Dutch fighter that held the line for a winter.

Sources: Wikipedia (Fokker D.XXI; Jorma Sarvanto), Air Force Magazine (Richard P. Hallion, “The Winter War”), SA-kuva Finnish Wartime Photograph Archive