01/31/2009. Remarks by Johan Visschedijk: "First projected in 1939 by Industrie Meccaniche e Aeronautiche Meridionali, the Ro.57 twin-engined single-seat interceptor fighter was designed by Ing. Giovanni Galasso assisted by engineers Callerio and Fiore, production deliveries commencing in 1942 to the Italian AF. The Ro.57 was of mixed construction, a wooden wing being married to a steel-tube, duralumin-covered fuselage, but, although of relatively advanced conception, the fighter was underpowered with two 840 hp Fiat A.74 R.C.38 fourteen-cylinder air-cooled radial engines. It retained the classic Italian single-seat fighter armament of two 0.5 in (12.7 mm) Breda-SAFAT machine guns, and lacked the maneuverability of its single-engined contemporaries.

Initially, the Ro.57 was delivered in small numbers to the home-based interceptor squadrons of the Italian AF, but its inadequate performance resulted in its adaptation for the fighter-bomber and dive-bomber roles. The modified version was designated Ro.57bis and differed from the interceptor version in having dive brakes, a crutch under the fuselage for bombs of up to 1,100 lb., and a heavier forward-firing armament, the twin 12.7-mm. guns being augmented by a pair of 0.787 in (20 mm) cannon. The Ro.57bis was introduced on operations early in 1943 and proved more successful than the original interceptor, but relatively few aircraft of this type were delivered."