Dewoitine D.520C.1
Description
RoleDay fighter
Crewone, pilot
Dimensions
Length28 ft 8"
Wingspan33 ft 6"
Height8 ft 5"
Wing area172 sq ft
Weights
Empty4,608 lbs
Maximum take-off6,129 lbs
Powerplant
EnginesHispano-Suiza 12Y-45
Power930 hp
Performance
Maximum speed329 mph
Combat range 
Ferry range777 miles
Service ceiling 
Armament
Guns1x 20mm cannon
4x 7.5mm machine guns
Bombs 

The Dewoitine D.520 was a French fighter aircraft that started entering service just prior to the opening of World War II. It was the only design that was a true match for the latest German types like the Messerschmitt Bf 109, but French building priorities were so confused that mass production didn't start until after the war started, and only a small number were available to meet the Luftwaffe.

Design of the Dewoitine 520 started in November 1936 at the private design firm led by Emile Dewoitine. Trying to address problems in earlier designs, he created a fighter using only the latest techniques and engines. The new design was to be able to reach 520km/h, and became known as the "520". Only months later the firm was conglomorated into one of a number of design-and-manufacturing pools, in this case SNCAM. Still known as the D.520, work on the design continued at the new company.

The first prototype D.520 flew on October 2, 1938, powered by the new 890hp Hispano-Suiza 12Y-21 liquid-cooled engine. The plane managed to reach only 480km/h in flight tests, much slower than expected. Most of the problem seemed to come from greater than expected drag from the underwing radiators, so these were merged into a single radiator under the fuselage. After minor damage in a landing accident the engine was upgraded to a newer -29 and included exhaust ejectors for added thrust, along with an adjustable prop. These changes were enough to allow the plane to reach its design speed.

The original prototype was followed in 1939 with two additional airframes with a new sliding canopy and a larger tail unit. These were armed with a 20mm cannon firing through the propeller spinner (a feature later found on most German designs) and two 7.5mm machine guns in small pods under the wing. The third also included a small tail-wheel instead of the original skid. Flight tests went fairly well, and a contract for 200 production machines to be powered by the newer -31 engine (later replaced by the -45) was issued in March of 1939. A contract for an additional 600 planes was issued in June, but this was reduced to 510 in July.

With the outbreak of war in September 1939 a new contract brought the total to 1280, with the production rate to be 200 machines per month from May 1940 onward. The Aeronavale then ordered 120 for their own use. Another Armee de Air order in April 1940 brought the total to 2250, and increased quotas to 350 a month.

The first production D.520 flew in November, powered by the 830hp 12Y-31 and armed with two 7.5mm machine guns in housings underneath the wings. It had a curved, one-piece windshield and a sliding canopy. The rest of the production machines were delivered with the 930hp 12Y-45 engine with a new supercharger and a Ratier 3-bladed propeller (a few had the -49 of 910hp). They were armed with a Hispano-Suiza 404 20mm cannon firing through the propeller hub, and four MAC 7.5mm machine guns in the wings. The curved, one-piece windshield from the prototypes was replaced with one containing an optically-flat panel.

The Groupe de Chasse I/3 was the first unit to get the D.520, receiving its first planes in January of 1940. These planes were unarmed and used only for training. In April and May they received 34 production machines, which proved to be very popular with the pilots. In tests against a captured Bf 109E-3 the D.520 proved to be 20km/h slower, but had much better control feel and manuverability.

When Germany invaded France on May 10th only GC I/3 was equipped with the D.520, with 79 planes. They met the Luftwaffe on May 13, shooting down three Henschel Hs 126s and one Heinkel He 111 without loss. GC II/2, GC III/3, GC III/6 and GC II/7 later received their D.520, and all took part in the Battle of France. A naval unit, the 1st Flottile de Chasse, was also equipped with the D.520. GC II/6 and GC III/7 converted to the D.520, but had been formed too late to see action.

By the time of the armistice at the end of June, 437 D.520's had been built, and 351 of these had been delivered. In that time they had 108 confirmed kills and 39 probables, losing 54 to enemy action. As French resistance collapsed in the middle of June, GC I/3, II/3, III/3, III/6, and II/7 flew their aircraft to Algeria. Three more from of GC III/7 escaped to Britain, and 153 machines remained in France.

In April 1941 production was started again to equip Vichy France Air Force units, and in June 550 were ordered to replace all other single-seat fighters. The plan was to have the D.520 eventually equip a total of 17 Groupes with 442 aircraft, three Aeronavale Escadrilles with 37 aircraft each, plus 3 training units with 13 aircraft.

The new planes saw some action over North Africa, but over 400 were captured on the ground in France when Germany took over the rest of Vichy France after Operation Torch. Some of the planes were transfered to the Luftwaffe for training purposes, as well as 120 to Bulgaria and 60 to Italy. Those that remained in France were used as trainers in the post-war period, serving in this role until 1953.