The D520 was created according to the 1934 technical assignment for a single-seat fighter to replace old machines (such as the D-510), which lost their significance with the advent of modern fighters, like the English Hurricane.

The draft design for D.520 was developed by young engineers Vautier, Rey and Castello under the leadership of Emile Dewoatin. They took the D.514 aircraft as a basis, on which the wing and tail unit were changed in the process. In 1936, the terms of reference were changed - the aircraft had a cantilever low-lying wing with ailerons, a closed cockpit, retractable landing gear and an engine with a capacity of about 1000 hp. with variable pitch screw.

The first flight of the D-520 prototype took place in October 1938.

The first serial D.520s entered the 1/3 fighter group for military trials in January 1940, where pilots of combat units were also retrained for a new type of aircraft. Despite numerous "childhood illnesses" (constant engine overheating, unreliable supercharger operation and frequent weapon failures), Dewoitine fighters quickly gained recognition among pilots due to their excellent maneuverability, comfortable cockpit with good glazing of the canopy and good takeoff and landing characteristics. And for the graceful, beautiful silhouette, D.520 was soon nicknamed "Miss France". In the process of serial production, the engine cooling system was modified, which made it possible to "squeeze" its maximum power out of the engine.

The aircraft's speed increased to 530 km/h. Unfortunately for the French, the pace of production increased slowly, and by May 10, 1940, when the Germans launched a "lightning" war in the West, the Toulouse plant had built 246 D.520s, of which only 76 were delivered to the Air Force. The only combat-ready unit armed with Dewuatin fighters was Group 1/3, which had 34 serviceable aircraft of this type. The pilots of the 1/3 fighter group entered the fighting on May 13, destroying three Hs 126 reconnaissance aircraft and the He 111 bomber in air battles without any losses on their part. The next day, the pilots chalked up six more downed enemy aircraft, including two Bf 109 and two Bf 110 fighters. This time two D.520s did not return from the mission. The results of the first battles in the sky showed that Dewoitine was somewhat inferior to the single-engine Messerschmitt in maximum speed, but surpassed it in maneuverability. At low altitudes, the Bf 109 had a better climb rate, but above 3000 m, the advantage in climb passed to the D.520.

On May 20, another group, equipped with Dewuatins, II/3, began combat missions, and at the end of the month changed its MS.406 to D.520 group II / 7. By this time, there was no more time left for a thorough study of the aircraft, and the pilots were involved in combat missions after two or three training flights in a new aircraft. In June, ten fighters left the assembly lines of the Toulouse plant every day, and this made it possible to re-equip other units with Dewuatins.

When on June 23, 1940, Marshal Pétain declared an armistice, the plant managed to produce 438 D.520 Dewoitins. Production continued during the German offensive, with a total production of 905 aircraft. Most of these aircraft were used by the Vichy France and transferred to other allies of Germany.

Photo	Description
	Drawing D 520 C
	D 520 C

Bibliography

• "Encyclopedia of military engineering" /Aerospace Publising/
• "50 best fighters of World War II" /Gennadiy Kornukhin/