Gaston let me clarify what you are saying:-
1. So a Spitfire Mark V out turns Spitfire Mark IX
2. FW190A out-turns a Spitfire Mark V (as admitted by Johnny Johnson in his book)
3. Therefore the FW190A out turns the Spitfire Mark IX, and so the Spitfire's only hope for victory was to 'boom and zoom' the better turning FW190?
Hmm, I think it's perfectly logical as you have stated it. However, using your previous suggestions, couldn't the Spitfire Mark IX pilot have throttled back and out turned the Spitfire Mark V? Where would that leave the FW190A?
Can you please explain the physics and dynamics involved. No mathematics please, I don't believe in any of that new age stuff.
-Actually Soviet tests show the Spit Mk IX to slightly out-turn the Mk V at full power, by a fraction of a second, but to me that is still a surprise by the rough rules I have that too much power "pulls" an aircraft "out" of its ideal sustained turn rate by forcing a wider radius...
Also the MK V nose is slightly shorter which in theory should also help it... But at full power unexpected things can happen...
Ideally sustained turns should normally never be done at full power anyway with nose traction, so full power tests (ALL WWII formal turn tests by test pilots are always at full or near-full power) are not the optimal way to properly test and compare sustained turn performance anyway...
According to my theory, you are absolutely right that a downthrottled Spitfire Mk IX could, in theory, downthrottle to improve its sustained turn rate. It could then possibly best a Spitfire Mk V, and could also in theory also best a FW-190A, despite the FW-190A's shorter nose, because the Spitfire has a much lighter wing loading.
(The short nose allows less "pull-out-of-the-turn" leverage, meaning that for a given level of power the short nose's turn-induced OFF-center "tendency to go straight" pull (off center because of the turn) taxes the wingloading less for the effort of lifting the nose: The short nose means off-center is LESS off-center: Less press-down leverage on the wings to lift the nose... This "leverage" does not apply to jet propulsion, which thrust has little, almost none, wingload-increasing thrust leverage since thrusting is from behind the wing's center of lift, which is also the pivot point used to lift the nose. Don't buy the nonsense that this pivot point is 500-700 ft. up in the center of the turn BTW...)
There are many other unpredictable, non-linear issues with sustained nose traction turn performance: I think aircrafts like the Me-109G can turn more tightly initially than a FW-190A or P-51D, but are for some reason aerodynamically "dirtier" while turning, and thus cannot sustain speed in a sustained turn to compete with these two: Oseau demise witness: "His Me-109G6/AS slowed down more in turns than his adversaries (P-51Ds). I had told Oseau the FW-190A was better than the Me-109G" Leo Shuchmacher of II/JG1. "Jagdwaffe Vol. 5 section 3, p.202 . Robert Forsyth.
The problem is that I am only aware of three European fighters where downthrottling was described to improve prolonged sustained flat turns: In theory it should work the same for all, but for some reason was not described for all...
The 3 Euro fighters where it IS described are the FW-190A, the Me-109G and the Merlin P-51 (in quite a dramatic fashion for this last one).
I never read it described for the P-47 despite reading thousands of combat reports, so it could be that peculiarities of both the P-47D and the Spitfire made sustained downthrottling unprofitable for these two types...
What do the P-47D and the Spitfire have in common? Surprisingly they have many handling similarities: They are both very light on the elevator controls at high speeds, but above 300 MPH the Spitfire is probably a bit more skittish, being saddled instead with a peculiar "mushing" tendency that allows it to raise its nose without tightening the turn, but instead allows it to shoot accross the circle with perfect 3 axis control while in a high speed "stall" (which is not a stall because of the full 3 axis control)...
Apparently you could not, above 250-300 MPH, pull back the Spitfire's stick top more than 3/4 of an inch without going into this "mushing" condition, but you could push your luck briefly to shoot "accross" the circle, "as if" you turned much tighter than in reality you could...
And yet, Spitfire dive pull-outs were very impressive, with little apparent tendency to tail-sink nose-up, and could be accomplished so harshly that the wings could be bent: Exact same issue with the P-47D, but the P-47D was stronger.
I think above 250-300 MPH a P-47D Razorback with needle tip prop will slightly out-turn a Spitfire, just like it does the Me-109G at ALL speeds, if for some reason mainly to the left... "The (needle-tip P-47D out-turns our Me-109G" On Special missions, Kg 200 (German-captured P-47D test conclusions: Look it up).
I think at full power the lesser traction of a needle tip P-47D prop allowed better low-speed sustained turning than an ALSO full power paddle-blade prop P-47D below 250 MPH (My boardgame got it wrong on this), because late 1944 bubbletop P-47Ds cannot compete in turns with anything, whereas the needle-tip Razorback could MATCH prolonged sustained turns with a FW-190A-6 in late 1943/early 1944!
I think a needle-tip prop had the SAME effect on the P-47D as downthrottling, but the P-47D being so big and heavy pilots felt psychologically unconfortable in lowering power in turns: As a result later Paddle-blade Bubbletops in late 1944 get matched in turns sometimes even by Me-109Gs(!!!)
It goes without saying, late 1944 P-47Ds cannot compete in sustained turns at all with late 1944 FW-190As... Not even close...
So why no Spitfire downthrottling accounts? I think the Johnny Johnson account is great evidence: Despite its
post-war hindsight, he describes going full power and shows no inclination to describe
that as a cause of his trouble with the FW-190A...
The American Merlin P-51 pilots were apparently less rigidly "by the book" than UK pilots, and happily ignored what they were taught in flight school with an apparently more acute and less dogmatic survival instinct:
http://www.spitfireperformance.com/mustang/combat-reports/339-hanseman-24may44.jpg I have yet to hear of a British pilot sustained turn downthrottling account, but it could be the case that the Spitfire's peculiarities did not make downthrottling profitable in sustained turns... Imagine for instance, that the Spitfire's aerodymamics IN TURNS at very low speed is unusually "dirty" below 200 MPH but much "cleaner" turning above 200 MPH: Then you would need to increase the power below 200 MPH to prevent the speed from decelerating far more than the tighter radius would profit you...
My bet is they followed the taught procedure, and the Spitfire WOULD beat other aircrafts downthrottled... They probably followed dogma, unlike the P-51 pilot quoted above... Downthrottling in sustained flat turns was never universally accepted by any air force, as Finnish Ace Karhila hints to us: "Most pilots increased power and then turned. In the same situation I would reduce power and then found I could turn just as well [in a smaller radius]"
I hope this clarified what I meant.
Gaston
P.S. This is a link to my boardgame:
http://forums.ubi.com/eve/forums/a/tpc/f/4811054957/m/5031083708?r=5031083708#5031083708 G.
