ORIGINAL: AA5BY
A high wing plane has a drag couple that plays into knife edge flight. Stick planes are often pretty good at aerobatics, but not so good at knife edge pulling hard to the canopy if they had one for the same reason as the Decathlon.
I'm not sure the inverted 45 deg upline test is a good indicator of proper CG for the Decathlon nor is inverted comparison with an elevator trim that is out of neutral.
Personally, I would balance it on the prescribed CG... then trim the decalage for neutral elevator... then re-balance for proper glide slope.
Are power on/off trims now the same... I ask because often when significant elevator trim exist, they are not.
I haven't taken the time/trouble to set the plane up and get the incidence meter set up on it. That's likely an excellent idea if for no other reason than to make sure I have the struts set right! They're currently set so they're the right length and there's no static twisting load only (they aren't forcing anything anywhere).
Haven't built anything other than ARF's in a long time, trying to get my head wrapped around which way to go with the wing to neutralize the stabilizer/elevator (w/obvious up trim)? Trailing edge to go up or down? Used to setting per plans and forgetting it - probably a good thing!
Re-balance for proper glide slope? That's something I don't ever recall doing?
Regarding power on/off trim, the plane is currently trimmed for near WOT (call it 3/4 speed?). Slower speeds (less power) will have the plane descending, and of course enough power application will check the decent? That doesn't seem too unusual on this plane, though the climbing under WOT is noticeable. Everything else I'm flying usually fairly neutral after trimming. Hadn't thought of that regarding the way this elevator has obvious up elevator trim. Would adding some down thrust be a good option/plan compared to messing with the wing incidence if that becomes necessary?
Thanks a ton for your thoughts! Will get back after seeing what the incidence meter has to say. Hopefully I'll be able to find something to zero out the fuselage without too much trouble! -Al