Great find JDbecks !!!
This report is very detailed and confirms exactly what I have always suspected about the FW-190D-9 compared to the FW-190A-8: It converted the great low-speed horizontal turn-fighter-only that was the FW-190A into a mediocre-turning Me-109G clone that had great boom-and-zoom vertical performance (better-diving but likely still not quite as good climbing as the Me-109G)...
I had previously read that actual FW-190A pilots found the D-9 to be inferior in maneuverability to the A-8, but superior in overall performance. They described the FW-190A-8's maneuvering superiority as being caused by the older aircraft type being "shorter-coupled", their words not mine, which I gradually integrated into my notion that the shorter nose could make, to some extent, a big difference in sustained turn handling by reducing the leverage of the prop's thrust to tax the wingloading...
Note those other aircrafts that shortened their noses by switching to radials, their significant consequent gain in combat maneuverability being usually attributed falsely to lighter weight:
Lagg-3 in-line converted to the radial La-5: Large gain in actual combat turn performance: La-5 was 250 lbs HEAVIER... Some Soviet turn times show them in a dead heat at 21-22 sec, but these tests were again usually run at full power by test pilots, so the 1300 HP Lagg-3 was handicapped with far less wingloading-taxing power than the 1800 HP La-5F, which could explain the similarity in sustained turn times at FULL power (a test pilot mania not always shared by combat veterans)... Lesser-powered Yaks do better for similar reasons: 19 seconds, but only about 1300 HP also.
Ki-61 converted to Ki-100: 100 + lbs HEAVIER Ki-100 had such a turn performance boost that it was considered by the Japanese, in extensive tests, to be so superior to the Ki-84 that ONE Ki-100 could take on THREE Ki-84s and still come out on top regularly, and REPEAT the feat by switching the pilots around...
One Ki-100 against one Ki-84 was considered no contest at all, and the Ki-100 would always win immediately, even with an altitude disadvantage... Again the same remained true while switching pilots... (These tests report are from Aeroplane's Ki-100 close-up article)
Such superlatives in turn combat doctrine (after all, the Ki-84 was some 25-30 MPH faster at least: 420 vs 390 MPH...) are not really imaginable with the Ki-61, though the radial's extra horsepower did undoubtedly help in the turn-climbing of the Ki-100...
The emphasis by the Japanese on turn-fighting was reflected by the Germans on the Western Front: The advice given to newly-arrived Eastern Front pilots was to ALWAYS turn with the Western Allies, and NEVER to try to climb or use the vertical... Boom and Zoom is only useable if you regularly enjoy an altitude and/or speed advantage: For various reasons, not often the case for either the Japanese or the Germans by 1944...
As one Lufwaffe senior officer put it: "All the aces sent to me from the Eastern front got shot down on the Western Front..."
I have even read one example of a Me-109G-14AS pilot that tried to climb, with MW-50 engaged, above diving Americans, and being pointed out as an example of a pilot who died because he refused to take the advice of turning and not using the vertical... This from a fellow pilot who survived the war...
By late 1944 70% of Luftwaffe front-line Western-Front strenght was FW-190As, while the BF-109G remained dominant in the East, and for good reasons...
The D-9's stall tests confirm my suspicions that the prop disc thrust contributes to taxing the wingloading: It is here plain to see:
Quote: "Controls remain effective up to the stall except in the power off condition wherein some difficulty is experienced in applying enough elevator to obtain abrupt stalls"
http://www.wwiiaircraftperformance.org/fw190/wright-field-fw190d-9.pdf Note the speed at which this occurs is not mentionned: The same probably occurs in fairly high speed power-off situations: The reason is that, in addition to the elevator's authority being curtailed by reduced prop wash, the REAL-LIFE wingloading is at the same time reduced by the power-off condition, making the stalls less "clean"...
You gotta love the clear and concise conclusion, confirming every sustained turning combat report I have read:
"1-The FW-190D-9, although well armored and equipped to carry heavy armament, appears to be much less desirable from a handling standpoint than other models of the FW-190 using the BMW 14 cylinder radial engine."
Any advantage this airplane may have in performance over other models of the FW-190 is more than offset by its poor handling characteristics."
Except for boom-and-Zooming tactics, I couldn't have said it better myself...
Gaston