Unknown

The SAI Ambrosini Unknown was a modest yet pioneering Italian aircraft produced in the late 1930s by the Società Aeronautica Italiana Ambrosini (SAI). Originally conceived as a versatile trainer‑fighter, the Unknown embodied the company’s ambition to blend high‑performance aerodynamics with ease of manufacture. Its first flight took place on 12 April 1938 at Reggio Emilia, piloted by test ace Mario Ghiberti, and the type quickly entered limited service with the Regia Aeronautica for advanced pilot instruction and dusk‑patrol duties.

The aircraft featured a low‑wing, all‑wooden monocoque fuselage covered with plywood and fabric, a 640 hp Alfa Romeo 115 radial engine, and fully retractable split‑type landing gear—a rarity among contemporaries. Hand‑crafted wing ribs gave a slim profile, while balanced ailerons and a split‑flap system provided excellent roll rate and short‑field performance. Armament could be customized, ranging from two 12.7 mm Breda machine guns to a single 20 mm cannon for combat trials.

Although only a handful were built, the Unknown proved crucial in shaping Italy’s pre‑war pilot training doctrine and demonstrated the viability of hybrid wood‑metal construction. Its design concepts later informed the more successful Ambrosini S.7 sport aircraft, leaving a modest but lasting imprint on Italian aviation history.