VTOL Quad Tailsitter control surface servos not moving

I’m working on a tailsitter with a similar tandem wing layout as Opener’s Black Fly. I have it working with two KK2 boards linked in series, but want to put the Pixhawk 4 in it.

I’m using the VTOL Quad Tailsitter airframe as a starting point. I would like to use all 8 motor ports on the Power Distribution Board as actual motors… I would like to control my flight control surfaces through the remaining 8 FMU/PWM outputs.

I’m using QGround v3.5.6

I can’t get my servos to activate… they are on the first 4 sets of pins of the FMU-PWM rail (1-4)(which is powered by a BEC) and AUX 1 is mapped to Channel 1 (Ailerons/roll etc.).

Any thoughts?

Summary: want to use the Main 1-8 as motors and FMU-PWM as control surface servos. Servos not activating. DX6 TX and Serial Receiver.

Hi @Tim.Talon,
The only quad tailsitter vehicle currently on PX4 has all he actuators on the MAIN

If you want to change that then changes in the mixer are required. Did you do that?

To understand your goal better: what’s the reason for wanting to have the control surfaces on the AUX?