Italian fighter pilots liked their
Centauro but by the time the war ended, fewer than 300 had been built. For comparison, the Germans produced 34,000 Bf109s.
By 1939, all the main Italian aircraft factories had begun designing a new series of monoplane fighter aircraft, using inline engines as opposed to the radial engines that powered the first generation Italian monoplane fighters used in the early years of World War II (fighters such as the Fiat G.50 and the Macchi C.200). This process saw the first generation radial-engined fighters re-equipped with the Italian-built copy of the Daimler-Benz DB 601 engine. Aircraft in this series were given alphanumeric designations ending in the number "2". However, the process didn't stop, and already in 1941, designers shifted their attention on the new, larger and more powerful
Fiat RA.1050, a license-built copy of the Daimler-Benz DB 605. Aircraft powered by this new engine became the "Serie 5", and all had alphanumeric designations ending in the number "5" (
Macchi C.205, Reggiane Re.2005, Fiat G.55
).
The Regia Aeronautica commissioned the production of 1,800 G.55s, later raising that number to 2,400. At the date of the Armistice, 8 September 1943, 35 G.55s of all
Series had been delivered, including three prototypes.From that date on, the
Centauro served with the
Aeronautica Nazionale Repubblicana (ANR), the air force of the new fascist state created in North Italy by Mussolini, with the assistance of the Germans. It still not exactly known how many "Centauros" were eventually requisitioned by the
Luftwaffe or those acquired by ANR. About 18 aircraft were expropriated by the ANR while 12-20 (possibly as many as 42, according to some official reports) were requisitioned by the Germans.
The Fiat factory, in Turin under German control, continued production for about six months and when on 25 April 1944, Fiat factories were heavily bombed (15 G.55s were destroyed. 164 "Centauros" had been completed, 97 of them being produced after the Armistice and delivered to the ANR.
Following the advice of Rustungs und Kriegsproduktion Stab (RuK), the German Control Commission, production was dispersed in small cities of Monferrato and production of parts were assigned to CANSA of Novara and AVIA in Vercelli. The parts were then assembled in Turin where the aircraft were to be flown by test pilots Valentino Cus, Rolandi, Agostini and Catella. Production slowed markedly, and was stopped by the German authorities in September 1944. A total of 148 G.55s were delivered to the ANR and, when the factory was captured, 37 more examples were ready, while 73 were still on the production line, in various degrees of completion.
In 1943 a German commission was very impressed by the Italian aircraft, the G.55 in particular, after testing. In general, all the
Serie 5 fighters were very good at low altitudes, but the G.55 was also competitive with its German opponents in term of speed and climb rate at high altitudes, while still maintaining superior handling characteristics. The definitive evaluation by the German commission was "excellent" for the G.55. German interest, apart from the good test results, derived also from the development possibilities they were able to see in the G.55 and in the Re.2005. Particularly, the G.55 was bigger and heavier and was considered a very good candidate for the new, significantly larger and more powerful
DB 603 engine, which was considered too large to fit in the Bf 109's airframe.
Luftwaffe G.55's remained in Turin, at the
Aeritalia plants, where they were used by German and Italian engineers to study the planned modifications and the possible optimizations to the production process. The DB 603 engines were used to build the G.56 prototypes.
Events in the war and the not yet optimized production process were the reasons for which the G.55 program was eventually abandoned by the
Luftwaffe. IMportantly, early production of G.55 required about 15,000 man-hours; while there were estimations to reduce the effort to about 9,000 man-hours, the well-practiced German factories were able to assemble a Bf 109 in only 5,000 man-hours.