Ambrosini S.A.I.403 Dardo
A lightweight single-seat fighter by Societa Aeronautica Italiana (Ambrosini), the Type 403-Dardo (Arrow) appeared in late 1942, developed from the S.A.I.207. The 403 differed by having a later series of 750-hp Isotta-Fraschini Delta inverted-V-12 aircooled engine, and constant-speed Piaggio propeller. The airframe was of similar all--wood form but had a new wing profile, greater area, redesigned tail surfaces - the incidence of the tailplane being variable in flight - a redesigned rear fuselage, a fully-retractable tailwheel, provision for wing guns and a more robust structure.
The Stefanutti-designed S.403 flew for the first time in January 1943, powered by an Isotta-Fraschini R.C.21/60 engine of 750hp which provided a maximum speed of 403 m.p.h. In the final two years of the programme all that happened was the first few items of production tooling, but no Dardos.
The armament was two 20-mm (0.79-in) Mauser MG 151 cannon in the wings and two 12.7-mm (0.5in) Breda-SAFAT heavy machine-guns above the engine. The Dardo--C was to be a long-range version with increased internal fuel and two drop tanks. An order for 3000 was placed with S.A.I. (800), Savoia-Marchetti (1,200) and Caproni (1,000), but only the prototype flew as the Armistice ended all further work.