Piaggio P.108B - part two

The Piaggio P.108B was the only four-engined bomber used by the Regia Aeronautica during World War II. It was a development of the previous Piaggio P.50-II and was designed by Giovanni Casiraghi who had been working before in the United States. It was an all-metal low-wing bomber with a retractable undercarriage and his design for the P108B won the official requirement for the 1939 bomber for the Regia Aeronautica defeating the CANT Z.1014 as it became obvious that other companies couldn't deliver the amount of required aircrafts before mid-1940s.
The first prototype felw for the first time on 24th November 1939 and the prototype performed very well for Italian standards and was assigned to the 274ª Squadriglia Bombardamento a Grande Ragio (274th Long-Range Bombardament Squadron) which was the only squadron to use it operationally.
The P.108B was widely used by the 274ª Squadriglia BRG and, by the end of 1941 it counted 391 flying hours. It was very expensive for the Italian economy (5.2 million lire of the time) but, it could perform considerably better than the cheaper, medium bombers of the Regia Aeronautica like the Fiat Br.20 or the SM.79 as it had more range than those. Also, when compared the total cost of raising a full squadron of P.108Bs, it was considerably cheaper specially in manpower terms as it took 54 crewmen versus the 130 required by a full squadron of SM.79.
Its engines were designed to be more powerful than those of the Boeing B-17 and it featured remote-controlled turrets, feature which was very original back in the time.
The second series of the aircraft, named P.108B Series II, had the nose turret removed. That change reduced aircraft's defences, but, as it operated mainly at night, speed increased greatly thanks to the weight reduction and the aerodynamical improvement gained.
The last aircraft delivered to the Regia Aeronautica in 1943, some days after 8th September, was given over to Lieutenant Gmeiner in Grottaglie field, in Puglia where it was taken over by the Allied forces which pushed it over to the USAAF. The aircraft was tested, specially the remote-controlled turrets which served as inspiration for those of the B-29.

Sources:
1. https://en.wikipedia.org/wiki/Piaggio_P.108#P.108B
2. La Bancarella Aeronautica - Ali d'Italia 15 - Piaggio P.108