When Emile Dewoitine's candidate for replacing France's obsolescent Nieuport-Delage NiD-622 sesquiplane fighters took to the air in the summer of 1932, it represented the synthesis of all that was modern in contemporary European fighter design. To meet the performance required by the French Air Staff's C1 specification of 1930, the new D.500 combined the rugged, all-metal construction that had characterized the firm's previous, parasol monoplane fighters with a state-of-the art, low-wing monoplane design laid out around the most modern and powerful, lowest-drag engine available, the new, 690-hp, supercharged, Hispano-Suiza HS.12X liquid-cooled V-12, and the most powerful gun carried by any contemporary, an engine-mounted, 20-mm Hispano HS-9 automatic cannon firing through the propellor hub. While none of these innovations was particularly radical on its own—all had appeared more than once during and after the war years—combining them all in a single, production airframe was revolutionary in 1932. Unfortunately, as is so often the case, what was futuristic at the time of its enthusiastic adoption—the D.500 handily won the C1 competition—was doomed to be rapidly outpaced in the technological race that it excited. By 1935, when the definitive D.510 variant began to enter service, retractable undercarriages, unbraced, cantilever wings, and still heavier armaments were already viewed as the coming norm, and more advanced types like the Polikarpov I-16, the Hawker Hurricane, the Seversky SEV, and the Curtiss P-36 were becoming available to foreign air forces. France's readiness to adopt new technology early thus had the perverse effect of retarding her aircraft industry in the critical years immediately preceding the Second World War.
The D.500 series was produced in three primary variants. The 100 D.500s were powered by the HS.12Xbrs, without provision for the engine-mounted cannon. Each was instead armed with a pair of synchronized, fuselage-mounted, 7.7-mm Vickers machine guns, later supplemented by a pair of 7.5-mm Darne machine guns mounted in pods under the wings, outside the arc of the propeller. These were followed by 133 D.501s powered by the HS.12Xbrs, armed with the cannon and a pair of wing-mounted Darne or MAC-1934 machine guns. The third variant, the D.510, retained the same armament as the D.501 but incorporated the longer, heavier, 860-hp HS.12Ycrs engine and a broader fin and rudder.
All three of the Dewoitine fighters proved popular in service and remained in service with regional, secondary units of the Armée de l'Air and Aéronavale until 1940. Export variants served in significant numbers with Venezuela, Lithuania, and China.
