The Piaggio P.111 was an Italian high-altitude research aircraft designed and built by Piaggio for the Regia Aeronautica (Italian Royal Air Force).

The genesis of the P.111 was in 1938, when the Regia Aeronautica awarded a contract to Piaggio to construct the prototype of a three-seat, twin-engine, high-speed, high-altitude bomber with a pressurized cabin.

Piaggio constructed a new radial engine especially for the P.111, the 745 kW (999 hp) 18-cylinder double-row air-cooled Piaggio P.XII R.C.100/2v, which was fitted with a two-stage supercharger.

Employed in research related to pressurization of the cabin of the Piaggio P.108 heavy bomber, it made 110 test and research flights before being retired and scrapped early in 1943.

[1] Data from Italian Civil & Military Aircraft 1930–1945 [2]General characteristics Performance