Just a few thoughts. The Spits and 109's in the Battle of brittain were close enough in performance that it's generally agreed pilot skill was the deciding factor. Therefore, you get Spit pilots insisting they were never out-turned by 109's and 109 pilots insisting they could turn inside Spits. Of course, there are different types of turns - continuous, instantaneous.
Regarding the quote you use from Leykauf, you left off the last part. He says, "In this way one could out-turn the Spitfire - and I shot down six of them doing it. THIS ADVANTAGE TO THE BF 109 SOON CHANGED WHEN IMPROVED SPITFIRES WERE DELIVERED."
The 109 was not a flying brick as many people who post in the forums would suggest. It had a gentle stall characterisitic that let good pilots get the most out of it's turning ability.
However, as the war went on it got heavy with more powerful engines and it's wingloading got worse, so it was probably a handful to fly even for experienced LW pilots.
The other problem with accounts as the original poster detailed is they don't take into account (how could they) The experience of the opponent and how familiar he was with his aircraft. Maybe those Spitfires weren't holding the edge of an accelerated spin like they really could because they where afraid they where already near the edge?
This is the reason why only documented trial data can be used because the instruments used to gather the data cannot lie only display the forces they where reading.
WW2 air combat rarely revolved around sustained turn fights.
The air battles were too large and typically the one shot down never saw his attacker. They did not have "icons" to tell friend from foe, they flew through poor weather, they had limited intel at the time, ect ect.
Most fighters shot down by another fighter would have been pursuing another fighter or bomber, or covering a wingman, or otherwise distracted when the enemy closed and opened fire. It made little difference if one plane or the other turned better.
There were some combats where they did do a lot of manuevering, yes, but it was the exception rather than the rule.
Read real WW2 air combat accounts. Many aces talk about closing and firing on enemy a/c that did little manuevering. They would see an opportunity, close in quickly, fire, and get the hell out of there.
Examples I will use is the P-47 Thunderbolt, it couldnt out turn Fw190s or Bf 109s in a sustained contest at most alts, but that made little impact on its success as an escort fighter. The P-38 couldnt out turn ANY Japanese fighter...yet it was the most succesfull US type vs the IJN and IJAAF. The Fw190A-3 could not out turn a SpitVb either. So how is it they were successfull types? If all that mattered was this turning ability?
There is a reason that biplanes were phased out of fighter design, figure it out.
109 was average turner compare russian plane like yaks.
Oleg had say yaks was better turner as spits, compare to the yaks are even spit average
turner.
Originally posted by LEXX_Luthor:
The Soviet pilot emphasized good Bf~109 vertical manuever but not pure horizontal turning. Here the Bf~109 was at best "average," although I would say vertical manuever superiority is, in general, more important than horizontal manuever superiority.
In conjunction with what Hastatus said you also have to take into account that these pilots had generally been flying for hours and where not on the top of their situational awareness.
Flying from point A to point B is pretty mind numbingly boring work, especially at altitude where everything is green,brown,blue and white without detail, much like driving down a long straight road like the interstates here in the US.