In 1942, the Spanish Ejército del Aires (air force) required a fighter to replace its ageing Fiat CR. 32, Polikarpov !-15 and I-16s. Consequently, the Spanish Aviation firm Hispano Suiza requested Dewoitine to undertake the design of a single-seat fighter designated as HS 50. The aircraft, would be powered by the Hispano Suiza 12Z rated at 1,300 h.p. at an altitude of 6,000 meters, would carry an armament of a single H.S. 404 20 mm cannon with 60 rounds and four machine guns in the wings. with 875 rounds apiece, and capable of a max. speed of 670 km/h (426 mph) which according to Dewoitine would make it comparable to the Spitfire, the ME-109, and even the North American P-51 Mustang. Late in 1942, Hispano Suiza completed a 1:1 wooden mock-up of the H.S. 50 at its La Tablada plant, in Seville. The Hispano 12 Z would be assembled in Spain from French-built components. But in June 1943, Hispano Suiza was absorbed by a new firm known as Hispano Aviación, which received an order from the Spanish Air Ministry for 200 Spanish-built ME-109Gs, and instead.
The design was also offered to Capitan Ismael Nuñez, the Argentine Air Attaché in April of 199, but, although the offer was considered, the fact that it had lost out to the Me-109G, and the unreliability of the powerplant installed aboard the Spanish-built Me-109G (HA 1109 KIll, flown first in March 1945 militated against it, and the Argentine Attaché declined the Frenchman's offer