To keep slack out of the control wires the rudder bell crank must be aligned to the rudder hinge line AND the holes in the servo bell crank and its pivot-point must be in line. What is often overlooked is many servo arms have holes that are not in line with the pivot point. Lay a straight edge across the bell crank for a quick check. If the inner or outer holes don’t line up with the pivot point then you have found the problem.
Read more:
http://www.rcuniverse.com/forum/m_98...#ixzz0sAEquRaD