Hello all again,
@liftbag it seems to be a good idea, with PWM management !!! thx so much
I read lot of things and it appear that ESC used for activating rotors works exactly as servos, so i'll try thursday (when i'll received CC3D and 4 servos).
I'll post infos and photos if it works, i'll test for first on my RC truck , i'll try to "stabilize" the dump (less cost and less engineering for parts)