Peter,
What about Motor thrust (up/down), that also has a significant effect on the upline, in your case more downthrust required.
The WindS pro & MythoS both have 1.5 upthrust, unusual in an F3A plane, emailed designer (Seba Silvestri) and he said it was required for the plane to go straight on the upline.
On my Element Contra I needed to slightly adjust the thrust line to get the model to fly straight up (wing incidence kept at +0.7), not really a surprise as I converted the model from conventional drive to contra so initial downthrust was a best guess.
Steve
Hi SAB
I should have prefaced my comment with "I've tried the down thrust route but there was insufficient space between the nose ring and spinner and the spinner lost!" I had a 2.5 mm gap all round the nose ring to begin with but that proved insufficient. Hence, the other route to jack up the wing incidence. If it had pitched to the u/c I would have reduced the wing incidence till the aircraft flew straight up hands off.
On my Element, I didn't have to make any up/down thrust adjustments. I guess that says more about the variation in airframe build than anything else.