Don't worry too much about negative dihedral on this model. I have one and thought the same as all of you, and got our club expert to try it out before I had a go. The two of use seem to think that the Cub only seems to have negative dihedral. Interestingly enough I have seen a few full sized Cubs take off and thay also seem to have a downwood curve in the wings. As for why yours didn't fly well, not sure, but remember one thing, dont fly this Cub with a cross wind, I't does a pritty good cart wheel if your not carful