Piaggio P.50, part two

The Piaggio P.50-II was a four-engined bomber of mixed wood and metal construction with a single tail and made of welded steel tube. It had a trycicle undercarriage with the main frontal wheels partially retracting into the engines' nacelles and the back smaller wheel was retractable as well. It was designed not by Giovanni Penna, the one who designed the original P.50-I, but by Giovanni Casiraghi, who started the design works on the P.50-II back in April 1936.
It was powered by four Piaggio P.XI radial engines yielding each of them 1000hp of power placed all of them in a conventional puller configuration, driving each of them a three-bladed propeller. Defensive armament consisted on five 12.7mm Breda-SAFAT machine guns, one in the front, another one in a spinal retractable turret, two in each laterals and another one in a retractable spinal turret that was never installed. Payload was 2500kg (5512lb) of bombs.
On 24th February 1938 the second prototype flew for the first time, piloted by Angelo Tondi, the same pilot as the P.50-I. Initially, it flew without defensive armament, but since the first trials at Guidonia test centre, close to Rome, on 30th January 1939, it was decided that the best defensive weaponry configuration would be the five machine guns listed before. However, after further tests, it couldn't achieve the expected performance requested by the order of the Regia Aeronautica due to the excessive weight of the fuselage. It also proved to be underpowered and remained unused at Guidonia.
A third prototype was built, made entirely out of metal, known in internal documents as P.50 Metallico (Metallic), which flew for the first time on 23rd November 1938 in the city of Pontedera, province of Pisa, with test-pilot Niccolò Lana at the commands. The performance of this third prototype was delayed until 1941 and it wasn't better than the second prototype, but by that time, the development of the model was abandoned in favour of the more promising Piaggio P.108B.

Sources:
1. https://it.wikipedia.org/wiki/Piaggio_P.50 (translated)
2. https://en.wikipedia.org/wiki/Piaggio_P.50
3. La Bancarella Aeronautica - Ali d'Italia 15 - Piaggio P.108