Ok, one last time: At WEP I assume 1800 hp is 1800 lbs of force in the prop disc: 80% of that pivoting back compared to the trajectory is 1440 pounds (working assumption), and I would use as a rule of thumb that this 80% prop face value means that, for every 1° of angle of attack increase, there is also 0.8° of extra lift through thrust slanting (0.7° if it was 70% of the disc face tilting back, but here 0.8° because it is 80%).
Tilt of the prop disc face is only an initial set up event: It lasts a proverbial micro-second: All further rotation is centered near CG-CL area...
This 1440 lbs prop value is gradually built up by 205 pounds for each AoA degree to 7°, maximum sustained angle of attack, totalling 1440 pounds at 7° as the assumed prop's fully topped-out resistance to assymetrical air inflow (due to turn assymetry).
The pilot stick is not beating the 1440 pounds at the nose by itself: The pilot cannot "feel" those loads, only the aircraft does, ever since the CL moved in front of the CG during its micro-second collapse... The CL is shifted in front of the CG now, and the increasing turn gives the CL 7° AoA of lift + 5.6° of thrust slanting: Total : 12.6° of equivalent AoA lift.
Say a 10 000 lbs aircraft at 7° AoA means 3Gs: That's 30 000 lbs of lift: + 80% of that means + 24 000 lbs of lift. Total: 54 000 lbs of lift.
A void is created above the wing when the CL shifted down and forward: This is the work of the mysterious "CL Collapse", so the top/bottom wing pressure imbalance IS there as the angle of thrust rotates down on top of the increasing AoA to the tune of plus 80% over the AoA value (up to presumed 7° "real" AoA max.)... That upper wing void seemingly remains during the turn, and increases in proportion to the AoA + thrust slanting total... (Weird!)
This above-wing extra void might be "maintained" by the bottom boundary layer leaking over the wing, going forward from the trailing edge (this is of course unknown at this point)... This is a direct result of the prop's initial resistance to the elevator: Resistance at both ends means slight CL "collapse": Barely a micro-second, and of course simultaneous with the initial prop "set-up" tilt...
If the CL is collapsing down and forward, it cannot be anywhere near the point of rotation during this micro-second collapse phase.... This is not hard to visualize! The aircraft is being loaded at both ends for a micro-second, which squeezes the CL forward as it goes down from the extra load...
After that:
Going straight down: CG with 30 000 lbs at 3 G. Going straight up in front of that now: Total CL at 54 000 lbs.
30 000 lbs down and 54 000 lbs up are inter-acting with each other as a "scissor action", relieving the elevator's effort to lift the nose, which is why the pilot cannot feel the prop's resistance to assymetry during the turn...
1440 lbs at the prop is not going straight downward for its part, but it does not want to go back and up either, since it pushes forward and slightly down....: To keep in balance the combined scissor action, the leverage advantage of the prop must be close to 30 000 lbs + 54 000 lbs divided by 1440 lbs: 58 to one for each up/down force's lever, 29 to one for both levers combined: For a ten foot nose that means here the CL is around 4.13793 inches in front of the CG when it has shifted forward under the initial micro-second elevator effort...
Why close to 29 to one? Because the nose does go up in the end, and the elevators also do help lift the nose a little after all...
And 54 000 lbs of load on the wing is like 5.4 Gs of wing bending at 3 Gs of turning....
And that is how engine power can affect the wingload.
And no, I can't make it any more simpler than that... If you don't want to understand it, don't.
Gaston
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