Viper,
Does it flutter on the ground or in the air, and what exactly do you mean when you say "downlines"? Reason I ask about the ground is because I have a Flip with digitals in it and sometimes it flutters on the ground. I think the reason is, the digitals are so precise any movement and the servos immediately correct. Its kinda hard to describe. It stops immediately when you move the control surfaces (on the ground) in the air you have, of course, air pressure on the surfaces, so no problems.