Two of the 15 D 500 series aircraft (the second and tenth) comprising the initial production contract for the new low-wing fighter monoplane placed with SAF-Avions Dewoitine were fitted with the Hispano-Suiza 12Ycrs (HS 77) engine as prototypes for the D 510. Heavier and longer than the HS 12Xcrs (HS 76) of the standard D 501 fighter, the HS 12Ycrs similarly catered for a 20mm cannon between its cylinder banks, and was rated at 775hp at sea level and 860hp at 4000m. The first of the D 510 prototypes flew (without the cannon fitted) on 14 August 1934, the second (with cannon) following on 10 December. Apart from engine, the D 510 was fundamentally similar to the D 501, the cannon being complemented by a pair of 7.5mm wing guns. In May 1935, the Ministere de l'Air placed an initial contract for 35 (later reduced to 25) D 510s, these being delivered from 9 October 1936. Seven more D 510s were then built for the Armee de l'Air as agreed replacements for a similar number of D 501s taken from the service's deliveries as part of the Lithuanian order. Follow-on contracts then called for a total of 80 more aircraft from which a contract for 24 D 510s from the Chinese Central Government was to be fulfilled. Other export D 510s were single examples to the UK and the Soviet Union, and two to Japan for evaluation purposes, and two, unofficially, to Republican Spain. These last had been the first two of a cancelled contract for Turkey and were ostensibly sold to the Hedjaz (Saudi Arabia). When it was revealed that the two D 510s had arrived in Spain, the French government insisted that their engines be returned to France. Eventually, both aircraft were fitted with M-100 (licence-built HS 12Ybrs) engines from a Tupolev SB bomber and allegedly saw some combat. Three Groupes de Chasse were still flying with the D 510 at the beginning of World War II, but re-equipped during the first months of the conflict. Two Escadrilles Regionale de Chasse in North Africa converted to D 510s in September-October 1939, flying them until mid-1940, and two escadrilles of the Aeronautique Navale formed on D 510s in December 1939 and May 1940.

Two of these old fighters were found in bad shape. Probably not used and scrapped ?

• 

• 
• 
•