In 1936, the D-513 fighter designed by Emil Dewoitine made its first flight. It was supposed to be the successor of the slightly outdated D-500 and D-510, built according to modern trends with a closed cabin and a retractable undercarriage. Unfortunately, the tests turned out to be very disappointing. At the same time, as part of the nationalization of the aviation industry, Dewoitine was incorporated into the SNCAM concern. The designer himself, however, did not give up the further development of the fighter and on his own, in cooperation with his engineers, developed a new design - designated D-520.