The first model, the P.50-I, was a four-engine shoulder-wing monoplane with a single large tailfin and rudder.
It was powered by four 544-kilowatt (730-horsepower) Isotta-Fraschini Asso XI.RC V12 engines mounted in tandem pairs on the wings, with each engine driving one three-bladed propeller; two of the propellers were mounted in a pusher and two in a tractor configuration.
For defense, the P.50-I had three machine gun positions, including a nose turret Piaggio built two P.50-I prototypes, the first of which—MM369—flew in 1937.
No production ordered resulted for the P.50-II, but Piaggio later applied the experience it gained from the design and construction of the three P.50 prototypes to the development of the Piaggio P.108 heavy bomber of World War II.
Data from Italian Civil and Military Aircraft 1930–1945[1]General characteristics Performance Armament