Modifying mixer generic flying wiing

PIXHAWK PX4 FLIGHT CONTROLLER_TARANIS X9D PLUS_GENERIC FLYING WING_MODIFYING MIXER

I own a flying wing. Normally flying wings have one pushing motor. Mine has two pulling motors on the wings. By using a servo Y cable I connect the two escs to main 4 (main 1 aileron left, main 2 aileron right, main 3 empty and main 4 throttle: these are the main outputs for flyingwings). It works.

My aim is to control the two motors separetly when in manual mode (manual=with my radio commands) I mean when motors are not under the total control of FC. I would use the rudder stick of the radio to input the different thrust to the motors.

I could connect one esc to main 4 already active for commanding motors and the second esc to (empty) main 3 that should be correctly activated for this purpose.

I think that on my taranis the two motors should be mapped to two different channels.

On QGC parameters list I find the mapping RC channels for throttle ailerons elevators and rudder (this last is not used in my airframe).

I did some tweaks in the generic flying wing main mixer.

But the flight controller emits 5 boops meaning that an error has occurred.

For now I don’t want to explain the tweeks I did.

Just i am asking if anyone knows how to achieve the result and gently give me some ideas.

So grateful to ones that have the knowledge of the stuff and will help me.

Marco