Hello!

Yes rudder could be used together with ailerons ...but it is only used(if ever)on large 2.5-4m slowflying high-winged airplanes...not for fast sport low winged airplanes.
Why !? Because the ailerons on large slow flying airplaens like th CUB sometimes work in the opposite direction. That is left aileron could induce a right turn. On fullscale high-winged aircraft it is normal proceedure to give both aileron and rudder to make a nice turn.
But it is a different ballgame on small models..so my advise is...Forget about coupled rudder and aileron!!! It will give you more problems then you
want.

Regards!
Jan K
Sweden