RE: Seagull Spacewalker II 120 Arf
Vagelis... thanks for the reply. If the CG is correct, then up trim would indicate a slight bit of trim is needed between the relationship of wing and stab and can be accomplished by either adding very slight positive incidence to the wing or negative to the stab.
I don't know the construction details of the Spacewalker... but if the stab is fixed, then the wing incidence should be adjusted slightly.
From the comment made by Sandman... that inverted his has a tendency to climb, that confirms that a little positive incidence of the wing is needed.
I would also check that both ailerons are not up slightly... which could cause the requirement of up trim of the elevator. In fact, if the wing required significant effort to adjust the incidence, I'd take a couple of turns of down trim on both ailerons and note any change for the better or worse.