Originally Posted by
Pilot DAR
I believe that the factors you suggest probably are genuine factors, however, in the context of all of the other factors and variabilities would not show themselves as clearly as you suggest. When I consider the differences in handling between two otherwise identical airplanes I have observed, I don't attribute any one factor, I consider them all.
And what about
identical airframes, of the same weight, same power, but with a different lenght of nose from a different engine?:
-
1946 US evaluation of FW-190D-9: "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."
- Donald Caldwell wrote of the FW 190 D-9’s operational debut in his "The JG 26 War Diary Volume Two 1943-1945" (pages 388 – 399): "The pilot’s opinions of the “long-nosed Dora”, or Dora-9, as it was variously nicknamed, were mixed. The new airplane lacked thehigh turn rate and incredible rate of roll of its close-coupled radial-engined predecessor."
Of note is that the reverse path to the above, that is to say, from long-nose inline to short-nose radial, so a significantly shorter nose on otherwise identical airframes, yielded massive gains in handing for the Ki-100 over the 300 lbs lighter K-61-I, which was not only lighter but very slightly faster as well...: The gains in performance were all in slow speed turning, and they were massive in favour of the heavier radial engine conversion, to the point of it being considered the best Japanese fighter of WWII by its users... A similar story with the (again heavier) La-5 radial engine conversion over the inline Lagg-3, but this time with a speed gain making the handling issue less obvious than in the Ki-100's case.
If we were to assume a relationship between this and and the distance of the propeller to the leading edge of the wing (which would affect the way the outgoing prop spiral is split for a given AoA change), then the initially visible conclusion would be that a shorter nose is less turn-averse than a longer one, but that turn-aversion is a similar factor for all. The other thing that would follow from this is that pilots should feel a nose down trim with more power during a turn, but they don't: It seems the effect is mostly neutral, or exactly the opposite...: They feel a slight nose up trim at low speeds during turns, when the prop is more heavily loaded by the turn.
If the prop was turn-averse on the vertical to fuselage plane (lower half unloaded/weaker), then the only way the pilot would not feel a nose down trim is that the wing is compensating with a more powerful nose-up trim... If that was true, then it means there would be a relationship between propeller load, wingloading and CL position, causing the wing to somehow produce this nose up trim without the tremendously favourable leverage of an 8 to 10 foot nose pulling down...
No relationship is currently recognized between the prop load and the wing load or CL position, at least not at a fixed speed that is unchanging.
Again, assuming these assumptions were all true, then the low-speed sustained turn performance should be increased by reducing power, and maybe even re-loading the turn-averse, de-pressurized part of the prop with a coarser prop pitch, this while reducing power...:
Hanseman (505 sq.) combat report, 24 May 1944 (Merlin P-51)
"Dogfight at 500 ft. (with a second higher aircraft,after
climbingfrom
130 ft., having closed to 50 ft. on a wheel down 109G that was landing)"--"At first he began turning inside me. Then he stopped cutting me offas
I cut throttle, dropped 20 degrees of flaps and increased prop pitch.Every time I got close to the edge of the airdrome they opened fire with light AA guns
."(Meaning several successive 360 turns near the same airdrome)--"Gradually
I worked the Me-109G away from the fieldand commenced to turn inside of him
as I reduced throttle settings."
Gaston