Meet the Caproni Ca.331.
It started life as a recon / fast light bomber right before ww2
Note the clean lines and the round nose reminiscent of the Heinkel He-111 or Mitsubishi Ki-46. It could carry 1000Kg of bombs (or one 500Kg bomb and a fuel tank); for defense, it had one powered turret above and another machine gun in the belly. Handling was said to be very good, for a twin engine plane. Considering its speed and handling, it could have been turned also into a nice torpedo bomber. Despite all the praises (it was also tested at Reichlin by the Luftwaffe with equally good results) it was never put into production.
When fortunes of war began to turn, in 1942, Caproni then thought of offering it again to Italy and Germany, this time as a night fighter (Turning an attack plane into a night fighter was also done with the Ju-88, another bomber with good speed and handling).
Note the stepped cockpit and an impressive array (well, for Italian standards) of 6 .50 machine guns in the nose, though at some point a combination of .50" and 20mm guns was tried. After the armistice, the sole completed prototype was disassembled and shipped to Germany and then lost forever.
What makes the Caproni Ca.331 a bit special was the choice of engine: it was an Isotta Fraschini aircooled inverted V12 engine named "Delta". This engine had been used in the successful Ca.313/314, a transport and light bomber that was also exported to other countries as well. (When Italy entered the war, Britain rescinded a pending order for 300 Ca.313, France for 200 units!)
Some other aircooled V12s exist, like the DeHaviland Gipsy Major (480hp), the Argus AS410 (460hp) or the Fairchild/Ranger V770 (500hp). The Delta had 700hp in its first version and up to 850hp at 5000m in the final version, with 2 speed supercharger and still using regular Italian 80/87 gasoline. Displacement was 26.6L and it weighted, dry but complete with accessories, a little more than 500Kg. The competing engines in the same power class were the Rolls Royce Kestrel or the Junkers Jumo 210, both V12 and both producing around 700hp, but liquid cooled. It's like British and German engineers said "inline engines must be watercooled" and Isotta Fraschini engineers answered "hold my beer"
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The Isotta Fraschini Delta was also unique in the fact that it used a dual overhead camshaft with hemispherical chamber, instead of the more common flat or penta-roof chamber used in other V12 of the period. Cooling of the rear cylinders was a bit troublesome, requiring careful design of the air scoop and of the baffles around the engine but it proved doable after a bit of trial and error. Exhaust valves vented between the two banks, so the collectors pointed downward and not on the side, as it's common in many V12s. It was a bit over engineered and, like many Italian aircraft engines of the period, it made extensive use of magnesium alloys for lightness, though this also meant that once it caught fire, it burned very well!