My thinking was in fact for larger sized planes. As a rule of thumb, the larger the plane, the easier they are to elevator and harrier. I do have two Morris profiles that will hover all day long, are light etc, but won't elevator or harrier at all. That is, a true elevator. Never had any luck with profiles or my Aeroworks Freedom 3D in an upright elevator. Can't explain why it did a sort of inverted on though