Suggest checking the direction of any expo. I fly Futaba so (-) expo is helpful. I put 3 more flights on a new 47" today and increased (-) Aileron expo to 30% from 25% at maiden. This aligned low rate aileron feel to that of my 62" Osiris for the way I fly. Osiris pilots enjoy crisp and precise rolling moments when the model is set-up as designed to fly. However, I could definitely see that if the expo is accidentally set in the wrong direction, that one would have a handful. I made that mistake two years ago when maidening an EF Taylorcraft 450 and had elevator expo dialed in the unhelpful direction. Crashed not far from rotation off the grass! LOL I learned all I needed to know about expo from that one. On another note, CG out of range could make any model unstable. 3DHS and AJ provide excellent specs and directions to get the best flight performance from their models so great care must be taken when using gear that is other than recommended. Suggest checking impact of pack size, weight, location on final CG. I am very impressed with the flying characteristics of both Osiris models and how well the little one flies like the big one (which flies like a 2m pattern ship) and have learned that any bad habits in my Osiris are those introduced by myself, the pilot / mechanic, LOL!