The Dewoitine D.520 was the best fighter aircraft available to the French Air Force (Armée de l’Air) in 1940. It was capable of holding its own against the Messerschmitt Bf 109E, but the D.520 was not available in sufficient numbers in 1940 to make a real difference.
Emile Dewoitine had produced a series of fighters for the French Air Force, starting with the D.101 of 1921. In 1934 most French fighter squadrons used one of the D.500, D.501 or D.510. However, these aircraft were clearly approaching obsolescence, and so in 1934 the French Air Force staff issued a specification for a new fighter. Dewoitine produced the D.513, an all-metal monoplane with retractable undercarriage, powered by an 860 hp Hispano-Suiza engine. The D.513 was not a success, and no order was placed. Dewoitine’s company, the Société Aéronautique Française – Avions Dewoitine was set to close at the end of 1936 once work was complete on the D.510.
In June 1936 Dewoitine left the company to found a new design office. The French Air Ministry was looking for a fighter capable of reaching 520 km/h (323 mph). Dewoitine’s first proposal could not reach this speed, but in January 1937 his team produced the design for the D.520. This aircraft would reach the required speed, now enshrined in the A.23 technical programme of 12 January 1937, but it had just been decided to adopt the M.S. 405, and so no order was placed for the new fighter.
Dewoitine soon found himself in a position to continue working on the new design. On 11 August 1936 a plan was put in place to nationalise the French aircraft industry, in an attempt to increase production and efficiency. Dewoitine’s old company was absorbed by the SNCAM on 4 March 1937. Dewoitine himself was appointed deputy managing director of the SNCAM (Société Nationale de Constructions Aéronautiques du Midi).
It was this position that allowed work to continue on the D.520. For the next year work progressed as a private venture. Finally, on 3 April 1938 the Air Ministry finally placed an order for two D.520 prototypes. The first prototype flew on 2 October 1938. This first prototype could only reach a top speed on 298 mph. A series of modifications followed, and in March 1939 the second prototype reached 327 mph (527 km/h) at 16,400 feet. This was good enough for the Air Ministry, and on 7 April 1939 an order was placed for 200 D.520 fighters.
The production version of the D.520 was powered by a 820 hp Hispano-Suiza 12Y45 engine. It had a top speed of 332 mph at 18,000 feet. It was armed with one 20mm cannon in the engine, with 60 rounds and four 7.5mm MAC 1934 machine guns in the wings, each with 675 rounds. The nationalisation of the aircraft industry had not produced the hoped-for increase in efficiency. Of 44 D.520s expected by the end of 1939, only 13 had been produced, and it took until April 1940 for the last problems to be ironed out. The first unit to gat the D.520, GC I/3, was not fully equipped with the new aircraft until 7 May 1940, four months behind schedule. Produce began to speed up during 1940, reaching 100 in May and peaking at ten per day in June. At the start of the German offensive SNCAM had produced 246 D.520s, and delivered 79 of them. By 25 June those figures had risen to 437 produced of which 403 had been delivered.
The Battle of France
When the German offensive in the west began on 10 May 1940, GC I/3 was the only unit using the D.520. During the next month four more units converted to the D.520 (including G.C. III/6 on the Italian front). In combat the D.520 proved itself to be an equal to the Bf 109E – the only allied aircraft engaged in France that could really make that claim. In tests against a captured Bf 109E-3 the D.520 was found to be slightly slower but more manoeuvrable.
The five D.520 units scored 108 confirmed victories and 39 probable victories. The confirmed victories included 23 Bf 109s and 9 Bf 110s. In the same period 106 D.520s were lost, although only 26 of those were lost in air-to-air combat. If the D.520 had been available in larger numbers in May 1940 it may well have denied the Luftwaffe control of the air over the western front.
After the Armistice
The D.520 remained in use after the Armistice. The German armistice commission allowed the Vichy air force to use the D.520 in Africa. The Germans even placed an order for 550 D.520s themselves (349 were produced between August 1941 and December 1942), using them as training aircraft. Some of these aircraft were sent to equip Vichy squadrons in Syria, where they saw action against the Allies in the summer of 1941. In this campaign the D.520 claimed 30 victories for the loss of 32 D.520s.
The D.520 had one last chance to fight the Germans after the Allied invasion of southern France in August 1944. Within days of the Allied landing the French Forces of the Interior formed a fighter group (Premier Groupe de Chasse FFI) which fought alongside the allies in southern France, using D.520s recaptured from the Germans, before being absorbed into the re-formed French Air Force on 1 December 1944. This fighter group used the D.520 from August 1944 to March 1945. By now the D.520 was effectively obsolete, but the Luftwaffe had been swept from the skies of southern France by Allied air power, and so the D.520 was able to play a role in the mopping up operations in south west France.
Span: 33 feet 5.5 inches
Length: 28 feet 2 5/8 inches
Empty Weight: 4680.3 lbs
Full Weight: 5901 lbs
Engine: 820 hp Hispano-Suiza 12Y45 12-cylinder liquid-cooled inline engine
Guns: One 20mm HS 404 cannon in engine hub, four 7.5mm MAC 1934 machine guns in wings
Speed: 331.8 mph at 18,044 ft
Ceiling: 34,450 ft