Which country designed the best engines for WWII?

[KevinB]

I'm thinking the question should be specific to what year?

The double-wasp and R-4360 major pineaple (variant) were the biggest/best engines at the end of WW2 IMHO. Starting the war the fuel injected Daimler-Benz DB 601 that didnt need carb-heat and would dive without leaning was best.

The Packard and RR merlins were awesome production machines too during and after.

KB

[engguy]

USA built the best aircraft engines.
As someone mentioned the improvements to the Packard Merlin, and even if some consider the Allison a dog, remember even the RR engines that are built for racing usually end up with Allison connecting rods in them.
Something else to consider, what brands and what country designed and built the most popular radial engines that are still flying today? I'd say the most popular "large" recip engine still in use today is the Pratt & Whitney R-2800, (gosh maybe even the R-1830) that is a testament to which country did build the best engines.
And we can't forget the R-3350 powering the big Martin mars fire bomber.
I don't think there too many running examples of what any of the other countries made during the war years. Other than RR liquid cooled engines.

[bada]

All those countries had marvelous engines, but my vote, in general, goes to the germans, because of the bmw801:
-small (front area-less drag),
-very well build cooler-system,
-injection (no need to explain),
-easy for maintenance (very fast attach-points on the fire-wall),
-delivered as a whole ready-to-use unit (power egg),
-best engine command-unit till the fifties (when a canadian company copied the design without authorisation) allowing an easier flight for the pilot,
-Solid as a rock (as the most of the radials anyway!),
-rather low weight compared to the PW's with the oversized compressors (or the complicated turbo system)
-and it's power starting at 1560 in41 and ending somewhere at +/-2050hp at the end of the war with max boost and C-3 injection (crump, if you read me and i'm wrong about that one, please correct me, i dream about the 1.65 C3injected bmw power and boost chart for the JABO-1000meters and Fighter versions!).

And i forgot about the beemer's sister in law: the Ash-82, with less qualities than the 801, but comparable in aerodynamical and power aspects, still in use today...even in the new build FW190's!

and about the pb that we only see PW's now: it's due only to the fact who won the war and who not