03/31/2013. Remarks by Johan Visschedijk: "Following an outline for the project by Ing. Giovanni Pegna, the Piaggio P.50 four-engined heavy bomber was the first aircraft designed by Giovanni Casiraghi.

The prototype P.50-I (s/n (s/n MM369)), which first flew in 1937, was a shoulder-wing monoplane with a single large tail fin and rudder, powered by four 730 hp Isotta-Fraschini XI RC twelve-cylinder V-engines mounted in tandem pairs on the wings, driving two three-bladed tractor propellers and two three-bladed pusher propellers. As defensive armament there were three 0.50 in (12.7 mm) machine gun positions, including a nose turret. A second P.50-I prototype (s/n MM370) was damaged in accident while landing at Malpensa airfield in 1938.

In 1938 the P.50-II (s/n MM371) appeared, fitted with a conventional engine configuration of four 1,000 hp Piaggio P.XI RC.40 radial engines, each driving a three-bladed tractor propeller. The defensive armament was increased to five 0.50 in (12.7 mm) machine guns. No production order for the P.50 materialized, but design and construction experience gained in the project, was used for the development of the Piaggio P.108 heavy bomber of WW II."