Originally Posted by
Rodney
Andy is correct, it is always best to have a little positive Ackerman in the pull-pull set up where the non pulled line goes a bit slack as the surface is moved from center. It is nigh on impossible to get any flutter or oscillation from this occurrence.
I would like to know how you came up with this? I have experienced this a few times. What I believe happens is that during a rolling circle or a flat turn while hard over on the rudder as the airplane is basically in a skid the buffeting airflow off the stab makes the rudder oscillate. having both cables taught solves the issue. This is well documented, try looking up CARF Extra 330 tail wag. It happened so badly to one pilot in the 2002 TOC that he actually lost his rudder. True, it's not common but it can happen. The best prevention is to set up the pull pull correctly from the get go.