Need Help, CG and Incidence Angle

[THY]

I currently own a Salto sold by icare, and since it did not come with any instruction, I have put the cg at 30% root chord for start. On test flight the plane pull up hard as I entered a dive test, I landed immediately, move the CG back a little and added down trim to compensate for level flight. Ok then, relanuch, it pull up again on dive test only this time being much more scary. It now would not climb even on moderate lift and wants to tip stall at every turns. I considered myself really lucky that it landed safely. After that, I have several more flights with different cg and incidence angle, and now it settled at a aft CG which partialy cure the pull up on dive problem however, it become really unstable in turns and is almost impossible to fly :confused: .

Can anyone please shed me some light on where and what the CG and incidence angle should be?

I know the airfoil is semi-symmetrical (HN-805), does it mean it requires a larger angle of attack/incidence angle to maintain level flight. Also it has a straight leading edge and a forward swept trailing edge, does it require a more forward CG.

Any help will be greatly appericate.

[feihu]

thy -

I don't know what the Salto is, but just by your mention of the CG located at 30% at the root chord of a fwd swept TE wing means that you have already started with a CG that is too far aft.
What you need is 30% of the MEAN AERODYNAMIC CHORD (MAC).
You can approximate the location of the MAC by measuring the wing chord that is 1/2 way out from the fuselage to the wing tip. Take 30% of that chord and project it back to the root chord, and that's where it should balance at the root.

feihu