Hi Stegl, what servo horns are you using for your Airtronics 820 servos? The stock disk ones are not large enough for ailerons. I have tried Dubro horns http://www3.towerhobbies.com/cgi-bin...?&I=LXEKC2&P=7
but these are slightly too loose.
Do you have experience with these "extra large" horns by any chance? They don't look extra large to me though.