Futaba WC1 9ZAP and R129DP receiver
 

I have a delta and wish to add air brakes to the twin rudders.left rudder on Ch4 right on Ch6. the rudders are working as normal at present.on mixer No4 Rudder/flap. I want to make them both turn inwards and act like an airbrake, as well as retaining the rudder movement when airbrakes are not being used, to be operated from a three position switch C.
I know it can be done as I have seen it, but I cannot fathom it out, any help would be much apreciated :mad:
Norman