With Respect to the Bud Andersen encounter, I read his book and got to talk with his at Oshkosh in '96. He made a point of mentioning the use of flaps on P-51 to optimize turn rate in this encounter, especially in the initial turn fight where they walked around the wagon wheel on the 109s. He said the first 15deg of flaps would dramatically improve the turn radius of a Pony, and that his Mustang Squad mates surprised a lot of 109 drivers in turn fights. But of course no single event dog fight should be SOLEY used to define the performance advantages of any two plane types, it seems this often happens on the Hist channel where anecdotal evidence is used in the place of actual performance stats.
I think the point above about arena fighting vs real life is spot on. Perhaps the turn radius performance difference between these planes is smaller than other real life factors that probably had a bigger influence, like e-states, fuel quality, maintenance, pilot conditioning, mental states, and pilot talent.
It would be interesting to read or see material that Chronicles the dog fights of German pilots. It would probably be full of stories of Hot soup Mustang pilots who thought they had a better plain and tried to turn fight a 109 and became a flag painted on the side of Ralls 109, and hence ex toll the performance virtues of 109 over Mustangs.
