Il Fiat G.56 era un aereo da caccia ad ala bassa a sbalzo realizzato dalla Fiat

Il Fiat G.56 era un aereo da caccia ad ala bassa a sbalzo realizzato dalla Fiat, progettato dall'ing. Giuseppe Gabrielli e derivato dal precedente Fiat G.55 Centauro.

Storia

La nascita del G.56 è direttamente connessa alla realizzazione, decisa dallo Stato Maggiore della Regia Aeronautica da un bando del 1942, di una nuova serie di caccia denominata "serie 5". Nel contempo vennero avviati rapporti di collaborazione più stretti con il Reichsluftfahrtministerium che portarono i progettisti italiani ad acquisire una serie di importanti informazioni tecniche. Gli sviluppi di tale collaborazione permisero la possibilità di usufruire dei motori tedeschi Daimler-Benz serie DB, inizialmente come fornitura dall'alleato tedesco e poi come produzione nazionale su licenza. Grazie a tali disponibilità vennero realizzati i Macchi M.C.205, Reggiane Re.2005 e Fiat G.55.

Di questi tre ottimi modelli, finalmente al livello se non addirittura superiori come prestazioni ai corrispondenti caccia nemici, in una serie di valutazioni comparative emergeva proprio il Fiat come miglior equilibrio progettuale in quanto sposava una semplicità costruttiva maggiore, che si concretizzava in minore tempo di costruzione, mantenendo comunque prestazioni assolute al livello degli altri due.

A seguito di queste incoraggianti valutazioni si cercò di convincere l'RLM ad adottare il G.55 nei reparti della Luftwaffe ed è a questo fine che venne ipotizzato di realizzare una versione ancora più prestazionale adottando il più potente Daimler-Benz DB 603A da 1.750 CV (1287 kW).

Una volta resosi disponibile il propulsore, arrivato direttamente dalla Germania, l'ingegner Gabrielli invece di progettare in toto un nuovo velivolo, anche al fine di accorciare sensibilmente i tempi di realizzazione, preferì adattare con poche modifiche la già ottima cellula del G.55 al nuovo motore. Il Ministero richiese inizialmente la costruzione di due prototipi del nuovo modello realizzato che assunse la denominazione di Fiat G.56, ai quali vennero applicate le matricole militari MM.536 e MM.537.

Le differenze nell'aspetto erano minime, conservando le dimensioni del precedente G.55 eccetto la lunghezza imposta dagli ingombri del DB 603, ma sostanziali in fatto di armamento. Al contrario del suo predecessore infatti si era riusciti a ricavare lo spazio per poter utilizzare, analogamente al Messerschmitt Bf 109F, la MG 151/20 da 20 mm nel mozzo dell'elica, eliminando però le due mitragliatrici sul cofano, mantenendo le due MG 151/20 nelle ali. Questo rese ancora più aerodinamico il muso che contribuì, nelle prove di volo effettuate, a raggiungere la velocità in volo orizzontale di 685 km/h, e che gli vale il titolo di più veloce aereo a pistoni mai costruito in Italia, dopo il Macchi-Castoldi M.C.72.

Curiosa la particolarità che il G.56 MM.536 venne dipinto con la livrea dotata delle insegne tedesche della Luftwaffe, come documentato dalle foto effettuate durante le prove di volo effettuate dal comandante Valentino Cus.

Il primo esemplare venne distrutto a seguito dei bombardamenti alleati dell'aprile 1944 e seppur si continuò a sviluppare il secondo prototipo, il MM.536, l'Oberkommando der Luftwaffe impose la sospensione del progetto.

La carriera operativa del G.56 finì ingloriosamente nei primi anni successivi alla fine della seconda guerra mondiale nella funzione di banco prova volante dei motori, alcuni dei quali equipaggiavano qualche anno prima i caccia alleati nemici, per le future forniture della rifondata Aeronautica Militare, e che scaturirono nella realizzazione del Fiat G.59 dotato di motorizzazione Rolls-Royce Merlin.

ENGLISH

The first Centauro to see operational use was the third prototype. On 21 March 1943, the aircraft was assigned to 20° Gruppo (squadron), 51° Stormo (wing) CT, based at Roma-Ciampino, for operational evaluation. In May, the G.55 followed the unit 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.[14] Pilots were delighted when they began to receive the new fighter in summer 1943.

In June, the first Serie I were assigned to Gruppo Complementare of 51° Stormo in Foligno, near Perugia, but in July the 11 G.55 of Gruppo Complementare were transferred to 353a Squadriglia, that already had in charge the "pre-series" machines, to operate from Roma-Ciampino Sud airfield. The 353a Squadriglia, commanded by Capitano Egeo Pittoni, flew many missions against the American bomber formations, but the flights were stopped when Rome was declared "Città aperta" (open city). On 27 August, the Squadriglie 351a and 352a left Sardinia and arrived in Foligno to be re-equipped with G.55. But at the date of the 8 September the G.55 had not been delivered yet. During the first week of September, 12 Centauros had been assigned to 372a Squadriglia of 153° Gruppo in Torino-Mirafiori. On 8 September 1943, the date of Armistice, the Regia Aeronautica had received 35 G.55s. Only one of them flew to southern Italy, accepting the invitation of Maresciallo d'Italia Pietro Badoglio to surrender to Allied forces.

ANR service

There still is no exact data about the G.55's captured by the Luftwaffe or acquired by Aeronautica Nazionale Repubblicana. About 18 G.55s were acquired by ANR while 12–20, or even 42, according to some reports, were requisitioned by the Luftwaffe.[14] The Centauro entered in service with the ANR; a decision was made to produce 500 G.55s, of which 300 were G.55/I and 200 G.55/II Serie II, armed with five 20 mm MG 151/20s and no machine guns (one in the centerline, two in the upper cowling, two in the wings). Only 148 were delivered to the ANR units that, as the number of available G.55s dwindled, were progressively re-equipped with the Bf 109G, of various sub-versions, even though Italian pilots preferred the G.55, with cancellation of production being extremely unpopular.

The ANR had two Gruppi Caccia terrestre (fighter squadrons), the first was initially equipped with the Macchi C.205, from November 1943 to May 1944, then, re-equipped with the G.55/I in June 1944 until it switched to the Bf 109G starting from November 1944. The 2nd Gruppo was the main unit equipped with the G.55, of which it had 70 examples from December 1943 – August 1944, before being progressively re-equipped with the Bf 109G.

The first unit in ANR to be equipped with G.55 was the Squadriglia Montefusco, in November 1943, operating from Piemonte until 29 March 1944, when it was absorbed by the 1st Gruppo and transferred in Veneto. The 2nd Gruppo was formed at Bresso. It was initially commanded by Lt Col Antonio Vizzoto, and later by Lt Col Aldo Alessandrini. It had three Squadriglie (the 4th, Gigi Tre Osei, the 5th, Diavoli Rossi, and the 6th, Gamba di Ferro). The unit operated near Milan and Varese until April 1944, then it was transferred near Parma and Pavia, then again near the Lake Garda (Brescia and Verona). At the end of May, the 2° Gruppo gave its G.55s to 1° Gruppo and re-equipped with 46 ex I./JG 53 and II./JG 77 Bf 109G-6/R6.

With the ANR, the G.55s gave a good account of themselves against Allied fighters like the Spitfire and Mustang.

German interest

In December 1942, a technical commission of the Regia Aeronautica was invited by the Luftwaffe to test some German aircraft in Rechlin. The visit was part of a joint plan for the standardization of the Axis aircraft production. In the same time, some Luftwaffe officers visited Guidonia where they were particularly interested in the performance promised by the Serie 5 fighters. On 9 December, these impressions were discussed in a Luftwaffe staff meeting and raised the interest of Hermann Göring himself. In February 1943, a German test commission was sent in Italy to evaluate the new Italian fighters. The commission was led by Oberst Petersen and was formed by Luftwaffe officers and pilots and by technical personnel, among them the Flugbaumeister Malz. The Germans also brought with them several aircraft including a Fw 190 A-5 and a Bf 109 G-4 for direct comparison tests in simulated dogfights.

The tests began 20 February 1943 with the German commission very impressed by the Italian aircraft, the G.55 in particular. 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, "excellent" for the Re.2005 although very complicated to produce, and merely "average" for the C.205. Oberst Petersen defined the G.55 "the best fighter in the Axis" and immediately telegraphed his impressions to Göring. After listening to the recommendations of Petersen, Milch and Galland, a meeting held by Göring on 22 February 1943 voted to produce the G.55 in Germany.

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. Other visits were organized in Germany during March and May 1943 in Rechlin and Berlin. The G.55 was again tested at Rechlin at the presence of Milch. Gabrielli and other FIAT personnel were invited to visit German factories and to discuss the evolution of the aircraft. The specifications of the German G55/II included the DB 603 engine, five 20 mm guns and a pressurized cockpit. The suggestion of weapons in the wings, limited to one 20 mm gun for each wing, originated the final configuration of the Serie I, while the DB 603 engine was successfully installed in what became the G.56 prototype. As a concrete expression of the German interest in the G.55, the Luftwaffe acquired three complete G.55/0 airframes (MM 91064-65-66) for evaluations and experiments providing three DB 603 engines and original machinery for the setup of other production line of the Italian copy of DB 605. Two of the 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. Later these two were converted to Serie I and delivered to the ANR. The third one was transferred to Rechlin for tests and experiments in Germany. The DB 603 engines were used to build the G.56 prototypes.

The interest in the G.55 program was still high after the Armistice. In October 1943, Kurt Tank, who previously personally tested a G.55 in Rechlin, and who had had nothing but praise for the aircraft, was in Turin to discuss G.55 production. However, 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. Early production of G.55 required about 15,000 man-hours; while there were estimates 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. The DB 603 were instead to be used in Tank's own Ta-152C.

Torpedo fighter

The Regia Aeronautica frequently used torpedo bombers to air-launch torpedoes, such as the trimotor SIAI-Marchetti SM.79 Sparviero medium bomber. These had some success in the early war years, inflicting considerable losses on Allied shipping in the Mediterranean. By late 1942 the aging Sparviero was facing continually improving Allied fighters and anti aircraft defences, leading to the Italian general staff exploring the idea of using well-powered, single-engined heavy fighters to deliver torpedoes – a concept known later as the "torpedo fighter". Such aircraft, based near the Italian coast, could potentially have an operational range of 300–400 km (190–250 mi), would be capable of carrying a 680 kg (1,500 lb) torpedo (a shorter and more compact version of a weapon carried by the SM.79) at relatively high speed, would also be better able to evade enemy fighters and/or combat them on equal terms.

While some consideration was given to adapting the G.55, Fiat began designing the G.57, a separate design powered by the 930 kW (1,250 hp) Fiat A.83 R.C.24/52 radial engine that was more capable of carrying a torpedo. Later, after the G.57 project was dropped, and given the ANR's continuing need for an aircraft that could replace the SM.79, the ANR engineers undertook the task of converting the Centauro for the torpedo attack role.

A production G.55 (military serial number MM. 91086) was modified to carry a 920 kg (2,030 lb), 5.46 m (17.91 ft) long torpedo. The engine coolant radiator, normally a single unit positioned on the belly of the fuselage under the cockpit area, was divided into two units mounted under the wing roots (similar to the layout used on the Bf 109), gaining a 90 cm (35 in) space where two racks were mounted to carry the torpedo. The tailwheel strut was lengthened and equipped with a strengthened shock absorber to keep the tailfins of the torpedo from striking the ground, and a drag-reducing cowling was added in front of the tailwheel to minimize drag from the lengthened strut. The G.55/S shared the same gun layout as the G.55/I, with the three MG 151/20s and the two Breda-SAFAT machine guns.

The aircraft, designated G.55/S, first flew in August 1944 and was successfully tested in January 1945, piloted by Adriano Mantelli. Despite the cumbersome external load, performance was good and the handling acceptable. The ANR ordered a pre-series of 10 examples and a production series of 100 aircraft, but the conclusion of the war put an end to the project. The G.55/S prototype survived the war and, after being converted back to the Serie I standard, it became the first G.55 to be delivered to the newly formed Aeronautica Militare Italiana (AMI).

Fiat G.56

The Fiat G.56 was basically a Fiat G.55 with a larger German Daimler-Benz DB 603 engine. 

Two prototypes were built, flight tests starting in March 1944. On 30 March, Commander Valentino Cus reached speeds of 690/700 km/h (430/440 mph). Official maximum speed was 685 km/h (426 mph) and the aircraft was armed with three 20 mm MG 151/20 cannon, one firing through the propeller hub, the other two installed in the wings. Performance was excellent, the aircraft proving superior to both the Bf 109K and Bf 109G and Fw 190A, outmaneuvering all types in testing. Production, however, was not allowed by the German authorities.

The Daimler-Benz DB 603 engine was a German aircraft engine used during World War II. It was a liquid-cooled 12-cylinder inverted V12 enlargement of the DB 601, which was in itself a development of the DB 600. Production of the DB 603 commenced in May 1942, and with a 44.52 litre displacement figure, was the largest displacement inverted V12 aviation engine to be produced and used in front line aircraft of the Third Reich during World War II.

The DB 603 powered several aircraft, including the Do 217 N&M, Do 335, He 219, Me 410, BV 155 and Ta 152C.

The Mercedes-Benz T80 land speed record car, designed by aircraft engineer Josef Mickl with assistance from Ferdinand Porsche and top German Grand Prix racing driver Hans Stuck, incorporated the third prototype DB 603. It was set up for the land speed record run attempt to operate on an exotic fuel mix based on a 63% methanol, 16% benzene and 12% ethanol content, with minor percentages of acetone, nitrobenzene, avgas and ether. Adding to the power output was a pioneering form of the Luftwaffe's later MW 50 methanol/water injection boost, and was tuned to 3,000 PS (2,959 hp, 2,207 kW)— enough, it was believed, to propel the aerodynamic three-axle T80 up to 750 km/h on a specially-prepared, nearly 10-kilometre (6.2 mi) length stretch of the roughly north/south oriented Berlin — Halle/Leipzig, which passed close to the east side of Dessau (now part of the modern A9 Autobahn) and with the actual length's location due south of Dessau, reworked to be 25 metres (82 ft) wide with a paved-over median, for the record to be set in January 1940 during Rekord Woche (Record/Speed Week). Due to the outbreak of the war in September 1939, the T80 (nicknamed Schwarzer Vogel, "Black Bird") never raced. The DB 603 engine was removed from the vehicle for use in fighter aircraft.

As Germany's largest displacement inverted V12 aviation powerplant in production during the war years, the DB 603 saw wide operational use as the primary engine type for many twin and multi-engined combat aircraft designs — the promising twin-engined Dornier Do 335 Pfeil prototype heavy fighter, the front-line Messerschmitt Me 410 Hornisse heavy fighter and Heinkel He 219 Uhu twin-engined night fighter were all designed for DB 603 power. The Dornier Do 217M and -N medium bomber and night fighter subtypes powered by inline engines, and the enormous sixty-metre wingspan, six-engined Blohm & Voss BV 238 flying boat prototype, essentially had their DB 603 powerplants installed within what appeared to be the same unitized complete engine/cowl/radiator assembly as a complete unit-replaceable "power system" for twin and multi-engined aircraft — this particular design featured a "chin"-style radiator installation directly beneath the crankcase, and the oil cooler placed on the dorsal portion of the installation for the earlier examples, as the BV 238 had no visible upper-cowl openings for engine cooling of any sort for its half-dozen unitized DB 603s. The He 219 airframe pioneered what is believed to be a Heinkel-specific Kraftei unitized engine package for the DB 603 engine using a well-streamlined annular radiator set for primary engine cooling between the propeller and its reduction gear housing with a nearly-cylindrical cowl behind it, pierced only by the twin rows of six exhaust stacks, one row per side. The characteristic portside-cowl supercharger intake for Daimler-Benz inverted V12s was usually accommodated away from the nacelle's sheetmetal itself for the Heinkel/DB 603 unitized engine package, most often within the airframe's wing panel design. The same Kraftei packaging for the He 219 was also used for powering the four-prototype He 177B strategic bomber series, and with an added turbocharger in each nacelle, the six ordered (two completed) prototypes of Heinkel's He 274 high-altitude strategic bomber project.

Variants:

Production versions

• DB 603A, rated altitude of 5.7 km, B4 fuel
• Power (take-off): 1750 PS (1726 hp, 1287 kW) at 2700 rpm at sea level
• Combat power: 1580 PS (1558 hp, 1162 kW) at 2500 rpm at sea level
• DB 603AA DB 603A with an improved supercharger, rated altitude of 7.3 km, B4 fuel
• Power (take-off): 1670 PS (1647 hp, 1228 kW) at 2700 rpm at sea level
• Combat power: 1580 PS (1558 hp, 1162 kW) at 2500 rpm at sea level
• DB 603E rated altitude of 7.0 km, B4 fuel
• Power (take-off): 1800 PS (1775 hp, 1324 kW) at 2700 rpm at sea level
• Combat power: 1575 PS (1553 hp, 1158 kW) at 2500 rpm at sea level.

Prototypes and other versions

• DB 603D, a DB 603A with propellers rotating counter-clockwise; production unknown
• DB 603F, a DB 603E with propellers rotating counter-clockwise; production unknown
• DB 603G (production cancelled)
• Power (max): 1900 PS (1874 hp, 1397 kW) at 2700 rpm at sea level
• Combat power: 1560 PS (1539 hp, 1147 kW) at 2700 rpm at sea level
• DB 603L/LA (prototype with two-stage supercharger, B4 fuel)
• Power (max): 2000 PS (1973 hp, 1471 kW)
• DB 603L/M two-stage supercharger, rated altitude of 10.5 km, C3 fuel
• Power (take-off): 2450 PS (2416 hp, 1801 kW) at 3000 rpm at sea level
• Combat power: 2100 PS (2071 hp, 1544 kW) at 2700 rpm at sea level
• DB 603N (prototype with two-stage supercharger, C3 fuel)
• Power (take-off): 3000PS (2958 hp, 2206 kW) at 3200 rpm at sea level
• Power (max): 2570 PS (2762 hp, 2059 kW) at 3000 rpm at sea level
• Continuous: 1930 PS (1904 hp, 1420 kW) at 2700 rpm at sea level
• DB 603S (DB 603A with experimental TK-11 turbo-supercharger) - Intended (not known if actually used) for the Heinkel He 274 prototype airframes.
• Power (max): Not known.
• DB 613 Coupled side-by-side DB 603s, meant to replace the DB 606 and DB 610, in prototype form only from March 1940 through 1943 and weighing an estimated 1.8 tonnes apiece.
• Power (max): Estimated at some 3,854 PS (2,833 kW, 3,800 hp) each per "power system".
• DB 614 a 2000 PS development.
• DB 615 Coupled DB 614 engines
• DB 617 A long-range derivative of the DB 603
• DB 618 Coupled DB 617 engines
• DB 622 A DB 603 with a two-stage supercharger and single-stage turbocharger
• DB 623 A DB 603 with twin turbochargers
• DB 624 A DB 603 with a two-stage supercharger and single-stage turbocharger
• DB 626 A DB 603 with twin turbochargers and intercooler
• DB 627 The DB 603 fitted with a two-stage supercharger and after-cooler.
• DB 631 An abandoned three stage supercharged DB 603G.
• DB 632 A projected development of the DB 603N with contra-rotating propellers.
• MB 509 Development as a tank engine for the super-heavy Panzerkampfwagen Maus.

All power data is given in metric horsepower as stated per manufacturer. Power (max) is Takeoff and Emergency power (5-min-rating), combat power is climb and combat power (30-min rating), continuous is without time limit.

After World War II

In 1946, Fiat restarted production of the G.55, using the large stock of partly complete airframes and components remaining in its factories. It was available in two versions, the G.55A, a single-seat fighter/advanced trainer, and the G.55B, a two-seat advanced trainer, whose prototypes flew on 5 September 1946 and 12 February 1946 respectively.

The AMI acquired 19 G.55As and 10 G.55Bs, while the Argentine Air Force purchased 30 G.55As, and 15 G.55Bs. In September 1951, units of the Argentine Navy and Army attempted a military coup against the government of Juan Perón. The G.55s and the sole Argentine G.59 of Grupo 2 de Caza of the Argentine Air Force attempted to defect to the rebel forces, flying to the Punta Indio Naval Air Base. The pilots were arrested on arrival and the aircraft immobilised, however, and took no further part in the revolt, which was defeated by Loyalist forces.

G.59

The production of these orders for G.55s for Italy and Argentina caused the available stocks of the Italian licence-built version of the DB 605 engine to run short. As there was still a demand for the aircraft, it was decided to convert the type to use the more readily available Rolls-Royce Merlin engine, with the first conversion flying in early 1948. The conversion was successful, and the AMI decided to convert its G.55s to Merlin power, these re-entering service at the Lecce flying school in 1950 as the G.59-1A and G.59-1B (single- and two-seat versions).

Syria placed an order for 30 similar aircraft, which by this time, were completely from new production as the stocks of G.55 components had been exhausted. Of these, 26 were single-seaters (designated G.59-2A) and the remaining 4 two-seaters (G.59-2B). A single G.59-2A was acquired by Argentina for evaluation, but no further orders followed from the South American republic.

The final versions were the G.59-4A single-seater and G.59-4B two-seater, which were fitted with bubble canopies for improved visibility. 20 G.59-4As and ten G.59-4Bs were produced by Italy.

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