my diablotin has a big wing rock problem, it has a big wing and is very light, I usually roll harrier but lately I have been doing harriers without rolling, close to the ground all around the model port, it is lots of fun working the ailerons and rudder to control wing rock and steer the plane. I noticed that I have a roll couple problem (due to the fixed design of this airplane big rudder inputs cause the airplane to also roll in the direction of rudder input) so I am experimenting with opposite ailerons mixed to rudder - this seems to make hovering and harriers much easier, now when I need a left or right rudder correction this is what I get - no more twisting or wing rocking which requires lots of aileron correction - I still have this on a switch because with this mix on you loose some aileron authority which negatively effects my slow rolling harriers so I am switching back and forth as needed. try this mix if you have an airplane that is roll couple sensitive - it might make a big difference for hovering and harriers. my diablotin has a symetrical wing like most 3d airplanes, a little dihedral would fix this problem but would negatively effect some other stuff.