Advanced French Fighters vs 1942/1943 contemporaries (1 Viewer)

[TM06]

There was zero chance of the HS 12B showing up in WW II.

Forget the 12B, that is a unicorn.
The whole H-S engine is problem, H-S was promising more power from less weight than anybody else. And the two other Hispano derived families (Swiss and Soviet) never came close to the power/weight ratio that H-S trying for. And they both had trouble with reliability/durability.

Why? If Hispano recognize the fundamental flaws with the 12Z engine - which they almost certainly would by around 1941 - then their attempts to fix it would likely result in the 12B or something similar. Looking at the images provided earlier in the thread paints it as just a solid engine rather than anything groundbreaking. The specs of the engine also place it quite squarely within the late-war inline V12's (DB 603, Jumo 213, Griffon VI / 61 / 65, Merlin 66, VK-107, AM-42, certain V-1710's) without being ridiculous. Given that the engine started development in 1945 and was ready for production in 1948, it being developed in 1941 would result in it being ready for production in 1944 - which also lines up with the previously mentioned V12's.

 

[Shortround6]

There is a real problem or rather a host of them trying to compare post WW II engine development to 1940-43 engine development.
For everything that makes development easier there is something that makes it harder. A 1945 design team has most of the knowledge that several other design teams spent 4-5 years acquiring. A lot of that covers materials and manufacturing techniques and processes. But the budgets and manpower are lower. In war time there are external constraints, like access to machine tools and materials regardless of cost/funding.

And an awful lot does depend on funding.

There seem to be two 12B power plants if not Three. There was a design study of a 12 -Z-B conducted in Barcelona which may have been the first. Double compressor with intercooler.
The French version/s of the 12B seems to have rivaled the Napier Nomad for complexity. Finding information on the "bare" engine is difficult and the ultimate version for power at 10,000 meters wound up with a 2190kg power plant. However that included the exhaust driven turbine/s that powered not only the 1st stage of the supercharger but also the 'fan' that provided the air flow through the radiators and then this air from the radiators was blended into mix of the exhaust gases (turbo waste gates?) the radiator air, and main exhaust from the turbo unit. Main exhaust and 2 concentric rings (?) around the main turbo exhaust nozzle. I have no idea how they handled the intercooler (liquid cooling tied to the radiators?)
Date of this contraption is a little iffy. 5 prototypes were built, it was never flown. Some information was published in the 1950 and 1951 editions of Jane's for basic engine but it was never marketed. The 12-B engine is supposed to have received it's approval tests in 1951 as a simple engine and the 1951/52 Jane's says the integral propulsion version was "under development"
This is from pages 368-370 of Hispano Suiza in Aeronautics by Manuel Lage.

I have no idea what was supposed to be ready for production in 1948.