Hi Matt,
Opps I`m wrong, not trying to step on your toes. I read it wrong But I`m right on the fix and the cause
I read it backwards on the outcome,and just remembered it wrong (what knife edge is doing what).I deal with this all the time.
If the wing inc. was off he would be carrying aileron trim.

If you adjust the elevator half opposing each other the center elevator trim effeciency is cut in half. you loose your down line trim power and need more down elevator mix for down lines . So now then you ,move the c/g back to compensate for that so you can trim a little down elevtor in ,causing the knive edge problem to get worse. not even to mention the ailerons needs trim or left rudder trim.

If the Spiral slip stream was our problem,
Why wouldn`t we have aileron trim mixed for level flight for power off ,power on or, opposing elevator trim mixed for landing after the power has been removed? It just sounds good and official to blame in on the Aero Jargon LOL
,Either the stab halves are off already ,elevator halves are off, c/g s to far back or, he has too much down thrust. nothing else can cause this problem. Not even the Spiral slip stream!

Guys,
Why would we build perfectly true airframes and then adjust them crooked ,that Jut don`t make sense.
we go through extreme efforts to build perfect airplanes and settle for crooked settings?
If we have spiral slip stream why dont we adjust the wings crooked ,or adjust the fuse length to make the rudder hit the left side of the spiral?
Or, find the problem on anything but knife edge? no where else , and it is dependent on how much rudder is used. Don`t you think if there were any spiral that the wing, gear , stabs would not straigten it out?

Matt,
I didn`t say adjusting elevators would not correct "THAT" Problem it`s just a bandaid for" That" problem a short cut, that will bite you elsewere.
anytime you adjust the elevator halves to correct that problem you cause 4 other trim compromises.
I can prove spiral slipstream is not the cause of the adverse knife issues do it all the time,it`s just a excuse we have used to stop trimming our airplanes. Mixing radios also made us lazy

I`ll say it again , Down thrust and rear CG is the Scourge of trimming pattern airplanes.
and the start of ALL compromises.

Ever wonder why your airplane bounced around in the wind? If you have any surface trimmed less than perfect the change in wind speed or direction will make you pay for compromises. Down thrust is the worsed offender second,, you guessed it C/G

Bryan