I cant answer you question about the first plane, it didnt last but 4-5-6 flights, so I never got a chance to test that one out. But however in rebuilding this plane I will how ever make sure the plane is balanced properly. But incase I will install electronics into my test bed kadet to make sure that the radio is working correctly. I do have a 2nd agwagon, needs covering, I will balacne that one and wring it out to see it I can get any of the same problems from the 1st agwagon.
I will say at the moment, pilot error, I dont think so, yet, I could be wrong.