Hi Koopernic,
Having lived in Arizona for 22 years, I am VERY familiar with Doug Champlin's Museum while it was in operation. The Fw 190D-13 is very impressive but was NEVER flightworthy. The engine has both an idle circuit and a run circuit in the injection system, and the run circuit had and is missing parts. So, yes, the aircraft did occasionally start, but also would NOT start about 1/3 of the times they tried. I was there for three attempts and it would not start one of those times. It is magnificent, to be sure, but with a series of only 17 airplanes, it was not a factor in the war. I think it was almost a Ta 152, which also wasn't a factor in the war and had a very meodiocre war record.
I'm under the impression the D-13 used the Jumo 213EB engine and an MG151 cannon instead of a Mk 108.
In any "what if" situation, there are always extenuating circumstances. Sure, had they been able to do so, they would have built more Fw 190 D-13s, but they didn't. If you want to believe they were a factor in the war, that's fine. We'll have to agree to disagree. I am a fan of the type, but there were simply too few to be of any real use to the German war effort. Same can be said of the Ta 152, amazing though it was.
About the Ta 152, they apparently built some 150 airframes, but only delivered some 67 aircraft to the front line units. They were basically a group of small-run airplanes with no spares and when the war ended, there were exactly two Ta 152Cs still operational with front line units. The Luftwaffe grounded all Ta 152Hs, an ignominious end for an aircraft with such great potential. I do not know why they were grounded, but I am sure they could have been corrected and returned to flight status had the war not been essentially over at the time. That does not constitute much of a threat in my book, and they didn't achieve much in real life.
Do I respect them as adversaries one-on-one? You bet I do; the Fw 190D-13, too. I would not especially want to meet one flown by a competent pilot if I were one-on-one with it. But they can hardly be considered as a factor in the war. The Fw 190D-13 and Ta 152 richly deserve a place among the pinnacle of piston fighter design, but they weren't a lot better than the other pinnacle pistons that were produced, also in small numbers. I'm referring to the P-51H (made WWII, but did not see combat), the unproduced Superbolt (prototype only), the Seafang (18 built, did not make WWII), the Sea Fury (1st flight Feb 45), etc. Last-gen pistons). None were f
actors in WWII, but they did display wonderful performance just before being retired to make way for jets.
All very good airplanes, but not in time to be war winners, at least not in WWII. But, you are correct, they were among the best piston fighters ever built.