The Piaggio P.108 Bombardiere was an Italian four-engine heavy bomber that saw service with the Regia Aeronautica during World War II. The prototype first flew on 24 November 1939 and it entered service in 1941. It was one of a handful of Italian combat aircraft that could match the best manufactured by the Allies. Four versions of the P.108 were designed, but only one, the P.108B bomber, was produced in any quantity before the armistice. The other variants included the P.108A anti-ship aircraft with a 102 mm (4 in) gun, the P.108C, an airliner with an extended wingspan and re-modelled fuselage capable of carrying 32 passengers, and the P.108T transport version designed specifically for military use. Only one P.108A and 24 P.108Bs were built. The combined total number of all versions (and prototypes) was at least 39, almost certainly more than 44. Most of the P.108Cs were subsequently modified for use as military transport aircraft and could accommodate up to sixty passengers. Nine P.108 Ts were used by Luftwaffe transport units until the end of the war. P.108B Design and development The P.108 was unique in the history of Italian aviation, as it was the only four-engine strategic bomber used by the Regia Aeronautica during World War II. It was a development of the earlier underpowered and wooden-structured P.50-II which was unable to take off at its designed maximum weight. The designer of the aircraft was Giovanni Casiraghi, an experienced engineer who had worked in the US from 1927 to 1936. On the basis of his experience he designed a radically new aeroplane. The P.108 was an all-metal low wing bomber with a retractable under-carriage. During the Air Ministry official requirement of 1939, it won the Regia Aeronauticas contract for a new bomber over the CANT Z.1014 as it became obvious that the other competitors could not deliver useful numbers of aircraft to the Italian Royal Air Force before the mid-1940s. The first prototype P.108B flew on 24 November 1939. It performed extremely well in a series of tests and required refining in only a few minor areas, but it took some time for pilots to get used to the new aircraft. The P.108 was delivered to a single unit, the 274a Squadriglia (274th Squadron), in 1941. But there were several accidents, one of them involving the son of Italian dictator Benito Mussolini. On 7 August 1941, Bruno Mussolini, commander