Thank you for all of you guys detail explanation , I think I know what is the thing. At first, I want to try by mixing aileron and rudder in the radio to test coordinated turn, but after knowing it doesn't work when flying inverted, I decided to drop it out. May be I will try by manual input . I am not sure I can do it because it seems too much and clumsy for me to handle three inputs, A, E, R simultaneously during a turn.

Anyway, no harm to give it a try at enough altitude. Thanks again !!!!!!!!!