ORIGINAL: Rodney
ORIGINAL: j.duncker
Slack should be avoided if at all possible even at maximum deflection because of the possibility of control surface flutter.
I agree that with small surfaces and slow speeds then flutter is unlikely but if you explore the envelope fully esp. in 3D style models then flutter might just bite one day.
My OMP YAK with a 120 AX would do climbing spins on full throttle both upright and inverted but I had to fix the slack in the elevator linkage to stop the whole tail fluttering. I was able to see it happen and get out of the flutter situation instantly so there was no damage.
Slack will not cause any flutter. I speak from many years of experience on using pull-pull on many planes of all sizes. You will not get any flutter when the none pull line goes slightly slack during movement away from neutral. In fact, if you do not have a bit of slack as you go off center (positive Ackerman) you are far more apt to be in trouble with excessive servo wear and high current draw. I always make sure that I have a bit of slack as the control is moved away from it's neutral position.
All I can say is that I experienced flutter and could repeat the situation. When I set up the elevator linkage correctly to avoid the slack in the non pull side I no longer got any flutter. I went on to fly that model for another 18 months without seeing a repeat of the flutter.