i have the older one with 1-jr8411 155 oz at 4.8 volts. i am running 6 volts and not a hint of flutter; make sure you have the linkage set up correctly. look at some of the 33-35 % planes out there that are only running one good strong servo and bigger ailerons. I have seen full passes with full throttle and not a hint of flutter. i didn't try to make the plane into a race horse, but i did full throttle passes to see if i would have any problems. i am running a 3.2 brison gasers on mine so speed is not what i or the plane are after. Have someone look over all when the fly day is there........