What If Aircraft - FIAT G.56

The most highly developed fighter produced in Italy during the war, the sole G.56 prototype was flown in March, 1944, under German authority. A G.55/I airframe was fitted with the improved DB 603A engine, which produced 1510 h.p. at 18,700 ft. and had a 1750 h.p. take· off and emergency rating. This engine was the only major change from G.55/I specification, yet it increased the length by 4 3/4 in., the weight by 440 lb., and the maximum speed by 40 m.p.h. Retaining the excellent manoeuvrability that characterized almost all Italian fighter designs, the G.56 possessed sufficient speed and firepower (armament being that of the G.55/I) to match any Allied or German fighter on even terms, actually proving itself superior to the Bf 109G and Fw 190A in comparative tests. The shortage of engines which limited G.55 production was even more acute with respect to the DB 603 unit, with the result that no production of the G.56 was seriously contemplated.

The G.56 weighed 6380 lb. empty and 8479 lb. loaded. Maximum speed was 425 m.p.h. at 22,960 ft., cruising speed 334 m.p.h., range 795 miles, and service ceiling 43,952 ft. Dimensions were identical to the G.55/I except for the length of 31 ft. 1 1/4 in.

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I haven't seen the original document but there is a meeting by minutes on record between Goering, Galland and Hitler specifically discussing the G.56 after Goering saw a prototype demonstration in Italy. He wanted them for the Luftwaffe. The meeting discusses difficulties in maintaining current aircraft production  for putting 603 engines in modified 109 production (ie. Me-309 which did prototype but production was cancelled in favour of Tank/FockeWulf development), the state of the war could not afford the industrial transitional period for such radical changes to the current model (it was hard enough going from Emil to Friedrich, let alone Gustav to something that resembles a Mustang with a bomber engine). Messerschmitt proposed making the Me-309 using 30% or more of Me-262 parts but it wasn't enough and Dora/Tank fighters enter production easily using readily modified Anton plants.

I don't even know if it's a genuine historical record or fiction but the point is the same either way.

So the German equivalent to the G.56 was really the Dora and Tank series fighters, over the course of 1945 it was planned that all versions in general service would transition to the DB-603 motor (variously EB/C, G and L/LA motors), even the Ta-152H was planned to switch to the DB-603LA from mid-45 production had the war continued, according to Dietmar Hermann.

Germany got its equivalent, just not until the engines were available.

The Italian use of the G.56 could not have been any better. It was only prototyped and there were no series engines available for mass production of a fighter installation any sooner than the Germans could do it. DB-603 production was very convoluted and sporadic, most of those used in wartime testing like the 603G were limited production only and did not enter mass production, and did not find its way into planned equipment in the Me-410B for example (so they used the same 603A engines as the 410A and only differed in equipment).

The 603E series (EB and EC motors) never entered mass production and was only prototyped in some fighter projects like the Ta-152C as an L motor substitute. The 603EB that was in Fw-190V21/U1 in November 1944 was designated 603E-V17 serial 525 and a prototype engine. The 603EC that was in Ta-152V6 in December 1944 was designated 603E-V19. The 603EC in Ta-152V7 was 603E-V20.

The 603LA did enter at least limited production but not until March 1945. A prototype 603LA-V16 was put in 190V21/U1 (the original airframe they modified to come up with the Ta-152C structure/layout based on a Dora testing prototype), that was in December 1944 but no more were put in aircraft until after March, in practise V7 was the only other prototype that got one.

So that only leaves the 603A which actually entered mass production and the 603G was only produced in limited numbers like the E series, prototyped and used only in testing, aircraft like the Me-410B which was supposed to have them, had 603A in reality.

I see no problem with the performance of a G.56 powered by the DB603A or the DB603AA (both of which were available, 85 x DB603AA were used on the He 219A2 I believe.)

The AA provides more power at altitude at the expense of lower sea level power. It opens up the possibility of optimising the G.56 DB603A for fighting below 5700m/19000ft and the G.56 DB603AA for fighting around 7300m (24000ft)

Obviously around 1944 improved version offering more power will need to become available, for instance the DB603AM.

DB 603A, rated altitude of 5.7 km, B4 fuel

Power (max): 1287 kW (1750 PS) at 2700 rpm at sea level

Combat power: 1162 kW (1580 PS) at 2500 rpm at sea level

DB 603AA DB 603A with rated altitude of 7.3 km, B4 fuel

Power (max): 1228 kW (1670 PS) at 2700 rpm at sea level

Combat power: 1162 kW (1580 PS) at 2500 rpm at sea level