I keep posting this little trick for warbirds and/or heavy models with rather heavy wingloadings. It is simple "WASHOUT!". Washout can be easily accomplished. Simply turn your ailerons to about 5 degrees UP. I have had warbirds that 2 degrees worked well. I had one small Spitfire, rather heavy and large engine for size, used for Scale Warbird Racing, that took 8 degrees up before it became a purring *****-cat. Starting with 4 degrees, it was near impossible to get a decent take-off. Finally at 8* it was just great until when overtaking a P-51. it pulled up and removed the Spit's tail assembly from behind the wing. YUCK!
Back to topic, I am now working with a student learning using a model with ailerons on the outer portion of the wing. It was set precisely, but the model had difficulty keeping from rolling past center when rolling out of a bank. With his permission I rolled the pushrods using only 2 turns, and just a small amount of up-aileron on each side. WOW, no more unwanted rolling, entire flight became very smooth and all flight included landing became very smooth and easy.
Warbirds really love a bit of washout. Try it, you will love it.
IT works!