The Fiat G.55 Centauro (Italian: "Centaur") is a single-engine single-seat monoplane fighter aircraft designed and produced by the Italian aircraft manufacturer Fiat Aviazione. It was operated by both the Regia Aeronautica and the Aeronautica Nazionale Repubblicana during the latter half of the Second World War.
The G.55 was developed and produced at Fiat's Turin facility. A key feature was its use of a inline engine (a license-built copy of the German Daimler-Benz DB 605 engine) instead of the traditionally favoured radial engine. It was armed with varying combinations of 20 mm MG 151/20 cannon and 12.7 mm (.5 in) Breda-SAFAT machine guns. The resulting fighter was relatively powerful, quick, and robust. The prototype G.55 made its maiden flight on 30 April 1942; after proving itself during competitive trials, the fighter entered quantity production and squadron service during the following year.Jackson 2003, pp. 76–77.
Being only active during the latter portion of the conflict, the majority of its operational service came after the Armistice of 8 September 1943 and thus was principally operated by the Repubblica Sociale Italiana. Wartime efforts to further develop the G.55 included the G.56, which was powered by the larger and more powerful German Daimler-Benz DB 603 engine; however, the G.56 variant is not believed to have ever been produced in quantity. Following the end of the conflict, Fiat opted to reestablish production of the G.55; in addition to its domestic use, postwar export sales were made to the Argentine Air Force and the Royal Egyptian Air Force. In this manner, examples were still being flown into the 1950s. Additionally, a dedicated trainer version, the G.59, was developed, powered by imported Rolls-Royce Merlin engines.
While Italian fighter pilots typically appreciated the Centauro, by the end of the conflict fewer than 300 aircraft had been completed. By comparison, the Germans produced 35,000 Bf 109s.U.S. Strategic Bombing Survey, Aircraft Division Industry Report, Exhibit I – German Airplane Programs vs Actual Production. Despite only being available in limited numbers, the G.55 proved itself to be an excellent high altitude interceptor over Northern Italy. During 1944, the Centauro routinely clashed with British Supermarine Spitfire, P-51 Mustang, P-47 Thunderbolt and P-38 Lightning, proving to be no easy adversary.Angelucci and Matricardi 1978, p. 234. The G.55 has been claimed to be the best aircraft produced in Italy during the Second World War Ethell 1995, p. 65. (a subjective claim also frequently made for the Macchi C.205 Veltro as well as for the Reggiane Re.2005 Sagittario). During 1943, after comparative tests against the Messerschmitt Bf 109G and the Focke-Wulf Fw 190, Luftwaffe officials declared that the Fiat G.55 was "the best Axis fighter" available at that time.Arena 1994, p. 23.
Design and development Background Throughout the 1930s, the Italian military authorities chose to use only radial engines to power their aircraft. Consequently, during the second half of the 1930s, the Italian aeronautical industry had been sufficiently de-incentivised to the point of completely avoiding the development of more powerful engines based on streamlined liquid-cooled designs, which would become popular abroad.Mondey 2006, p. 153.Cattaneo 1966, p. 3. However, 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 the Second World War (fighters such as the Fiat G.50 Freccia and the Macchi C.200 Saetta). This process saw the first-generation radial-engined fighters re-equipped with the Italian-built copy of the Daimler-Benz DB 601 engine, the so-called Serie 1/2, whose most prominent representative was the Macchi C.202 Folgore. This was an aerodynamically revised Macchi C.200- also known as Macchi C.201 with a V-12 instead of a radial engine. Aircraft in this series were given alphanumeric designations ending in the number "2".
This re-engining initiative had quickly proved to be beneficial, and so various Italian figures were keen to continue exploring this direction. Accordingly, during 1941, designers shifted their attention on the new, larger and more powerful Fiat RA.1050, a license-built copy of Germany's Daimler-Benz DB 605 engine. 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). Fiat designer Giuseppe Gabrielli, while experimenting a new version of his Fiat G.50 fighter, equipped with the DB 601, started a new design that was to be powered by the DB 605.
Into flight The first G.55 prototype flew on 30 April 1942,Green 1961, p. 167. piloted by commander Valentino Cus, immediately showing its good performance and flight characteristics. It was armed with one 20 mm MG 151/20 cannon with 200 rounds of ammunition, installed between the cylinder banks and firing through the propeller hub. In "Sottoserie 0" airframes, there were also four 12.7 mm (.5 in) Breda-SAFAT machine guns; two in the upper engine cowling, and two in the lower cowling, firing through the propeller arc, with 300 rpg. This layout soon proved to be troublesome, both for rearming and for the servicing of the lower cowling mounted machine guns. For this reason, the two lower machine guns were removed, and replaced with a 20 mm MG 151/20 in each wing, in the later production series, the Serie 1 (for a total of three cannon and two 12.7mm machine guns, although this varied; some had machine guns in the wings instead of cannon).
The prototype was flown to Guidonia, where it was put into trials against the other fighters of the so-called Serie 5: Macchi C.205V Veltro and the formidable Reggiane Re.2005 Sagittario, all of them using the powerful, license-built Daimler-Benz DB 605 engine. The trials showed that the Centauro was the second best performer overall, and it won the tender set by the Regia Aeronautica. The C.205V was good at low and medium altitudes, fast and with good diving characteristics but its performance dropped considerably over 8,000 m (26,250 ft), particularly in handling. The Re.2005 was the fastest at high altitudes and best in dogfights, but suffered from vibration which turned out to be a balance problem. This was corrected, but the 2005 was still the most technically advanced, intricate, and therefore time-consuming of the three to produce, which made it unattractive at that stage of the war. The G.55 was chosen for mass production, along with the C.205. The G.55 prototype reached 620 km/h (390 mph), fully loaded, and without using WEP (war emergency power), at 7,000 m (22,970 ft). This was a little less than expected, but it had a strong airframe and was the best aircraft regarding handling and stability at every altitude. The only negative assessment noted by G.55 pilots was pronounced left-hand yawing at takeoff due to the powerful engine torque. This was partially remedied by a slight offset positioning of the vertical stabilizer to counteract the torque.
By early 1943, increased Allied bombing raids over Italy had shown that there was no suitable high-altitude fighter to deal with them effectively. The Macchi C.202's performance decreased above 8,000 m (26,250 ft), the typical altitude of the bombers, and its light armament of two 12.7 mm (.5 in) and two 7.7mm (.31 in) machine guns was hardly adequate to bring down heavy bombers. Of the Serie 5 fighters, the Centauro showed the best high-altitude performance, due to its large wing surface area. Also its powerful armament, along with the generous ammunition supply (the G.55 had 250 rounds of 20 mm ammunition in the centerline cannon as opposed to 120 rounds in the Re.2005) standardized in the production Serie I, was sufficient to bring down US heavy bombers.
Production The Regia Aeronautica commissioned the production of 1,800 G.55s, later raising that number to 2,400.Green and Swanborough 1974, p. 238. A pre-production series of 34 examples was ordered: these aircraft were mostly based on the prototype, with minor changes to improve its flying characteristics. They had a different weapon layout, as stated above, with the two lower cowling machine guns moved into the wings. Only 19 of the 34 commissioned aircraft were built, and six of them were converted to the Serie I standard at the factory.
The production version, named Serie I, had the standard armament of three 20 mm MG 151/20s and two 12.7 mm (.5 in) Breda-SAFAT machine guns, plus two underwing hardpoints, allowing it to carry either two bombs (up to 160 kg/350 lb), or two drop tanks (100 L/26 US Gal). At the date of the Armistice, 8 September 1943, 35 G.55s of all Series had been delivered, including three prototypes. Of these, only one was flown to South Italy to join the Italian Co-Belligerent Air Force (a second G.55, MM.91150, was obtained by the Allies in summer 1944, when test pilot, Serafino Agostini, defected with an escaped British POW, an RAF officer, sitting on his knees. The aircraft was then taken on charge by the RAF and transferred to the Central Fighter Establishment of Tangmere, Great Britain, on 17 March 1945, with the identification number VF204 applied, was put in the depot at Ford; its final fate is unrecorded.Sgarlato 2009, p. 44.Green and Swanborough 1974, p. 239.)
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. On 25 April 1944, Fiat factories were heavily bombed: 15 G.55s were destroyed, as well as some trimotor Fiat G.12 transports, BR.20 bombers, and CR.42LW biplane fighters ordered by the Luftwaffe. 164 "Centauros" had been completed, 97 of them being produced after the Armistice and delivered to the ANR. Following the advice of Rüstungs 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.Sgarlato 2009, p. 44-46. Production slowed markedly, and was stopped by the German authorities in September 1944.Green and Swanborough 1974, p. 261. 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.
Operational history The first Centauro to see operational use was the third prototype. On 21 March 1943, it was assigned to 20° Gruppo (squadron), 51° Stormo (wing) CT, based at Roma-Ciampino, for operational evaluation. In May, the unit transferred to Capoterra, near Cagliari having its baptism of fire on 5 June 1943 against Allied aircraft attacking Sardinia. The two first pre-production series flew, respectively, on 10 April and in May 1943. In early June they were assigned to 353a Squadriglia (flight) CT based in Foligno, Umbria, were, until August, were transferred nine more aircraft.Sgarlato 2009, pp. 42–43. Pilots were delighted when they began to receive the new fighter in summer 1943.Gunston 1988, p. 253.