Using servo output 5 to produce a signal that is the average of all motor PWM outputs

I need an output that is the sum of all the motor (Servo 1-4) outputs. Using the “Advanced Configuration” in MP I set SERVO 5 to be “connected” to the THROTTLE using mask “70”. But I get no PWM signal from the channel 5 servo output.
I can’t use the RC throttle input to produce this signal because I want a signal that is valid in other modes (like AUTO).
Does anyone know of how I can get the PWM signal that I want?

@charles_linquist have you had any luck? I’m attempting to do something similar however i’d like to maintain control of that fifth motor output. Or just shut it off.

If you are using the latest Pixhawk code (beta version) - you can set any unused output to produce the internal “throttle” signal, which is basically the average of all the motors. Just set the SERVOx output to “81” (which is not yet mentioned in the Mission Planner XML file, but is listed in the online manual. There is also a new BOOST parameter which is basically the scale factor of the SERVOx output. There were some issues with these functions, but I know the team is working on them.