PX4 Fixed-Wing: Motor Not Spinning During Mission/Takeoff Despite Working in Actuator Test (Pixhawk 2.4.8)

Pixhawk
1

Hello,

I’m trying to fly a fixed-wing aircraft using Pixhawk 2.4.8 with PX4 firmware through QGroundControl. I’ve done most of the setup and calibrations, but I’m stuck at a point where the motor does not respond during mission execution or takeoff mode, even though everything works fine in actuator testing.

My Aircraft Setup:

  • Fixed-wing aircraft with a T-tail configuration
  • Two ailerons, one on each main wing, working in opposite directions (for roll)
  • Two elevetrons at the tail, working in the same direction (for pitch)
  • One rudder for yaw control
  • Two motors mounted on each main wing (currently testing with one motor connected)

QGroundControl Assignments:

  • MAIN1 → Aileron
  • MAIN2 → Elevator (elevetrons)
  • MAIN3 → ESC (Throttle)
  • MAIN4 → Rudder

Control surfaces and motor behave correctly during Actuator Testing, including throttle movement—motor spins fine there.

The Problem:

  • When I arm the aircraft and start a Mission or enter Takeoff mode, the motor (MAIN3) does not spin at all.
  • The aircraft arms successfully, control surfaces respond, but there’s no power to the motor.
  • In Actuator Test, throttle slider moves and the motor works, so I know wiring and ESC setup are fine.

What I Need Help With:

  1. Are there any specific parameters that might block throttle during autonomous modes like Takeoff or Mission?
  2. Could PWM_MIN, PWM_MAX, or Disarmed values affect motor behavior in this case?
  3. Is there any setting that I’m missing for throttle to activate properly in flight modes?
  4. Any PX4-specific setup I should check to allow throttle output in auto modes?
    WhatsApp Görsel 2025-05-23 saat 21.25.50_945f7d57
    WhatsApp Görsel 2025-05-23 saat 21.25.50_945f7d571600×844 114 KB

LOG:https://review.px4.io/plot_app?log=8ff3c317-44d0-4135-92e4-e01e02aadcae

Thanks in advance for your help.

2

As your told you have 2 ailerons, 1 rudder, 1 elevaor and 2 motors.
in PWM MAIN select,
MAIN 1 → Aileron left
MAIN 2 → Aileron right
MAIN 3 → Rudder
MAIN 4 → Elevator

you need to set proper disarm, PWM max and PWM min values for each servos.

Now you have two motors,
So select Motor = 2 one top left

in PWM MAIN,
MAIN 5 → Motor 1
MAIN 6 → Motor 2

You need set proper max and min PWM values for each motors after ESC calibration.

you can follow instruction from here to adjust max and min values of PWM.