Programming differential thrust for my flying wing (using a DX9)

After I finished my Baby Divine flying wing, I decided to take advantage of the twin motors to add differential thrust – the ability to vary the thrust from right to left. This will add some yaw control. Since flying wings typically have no yaw control, this should be a real plus.

Here’s the plane:

The left-hand motor turns normally with standard prop.
The right-hand motor is reversed with pusher prop.

The left-hand motor plugs into the actual throttle channel (THR) on the Rx.
The right-hand motor plugs into the AUX1/FLP channel on the Rx. Since I’m using the FLP channel, I first have to disable the flaps. Otherwise, if I accidentally hit the flap switch, I alter the thrust to the right-hand motor.

Disable Flaps

AX1 > FLP
RATE: -100% -100%
OFFSET: 100%
SWITCH: ON

Next, I mix the throttle into the flap channel. I leave trim active.

Mix Throttle into Flap Channel

THR > FLP
RATE: -100% -100%
OFFSET: -100%
SWITCH: ON
TRIM: ACT

Lastly, I mix the rudder into the throttle channels for each motor. I put this mix on Switch B so I can disable it if I want to. I initially set the rate to 60%. Set it to whatever you want, but make sure both mixes use the same rates. The higher the rate, the more the rudder input affects the speed of the different motors.

Mix Rudder into Left-hand motor:

RUD > THR
RATE: -60% -60%
OFFSET: 0%
SWITCH: B
TRIM: INH

Mix Rudder into Right-hand motor:

RUD>FLP
RATE: -60% -60%
OFFSET: 0%
SWITCH: B
TRIM: INH

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