Flying wing X5 setup questions

PX4 Autopilot
1

Hi,

I was hoping someone could help me here I have a few setup questions listed below.

  1. I rotated my pixhawk 90 degrees to the left so I set yaw at 270 degrees for board orientation. Now my mixing seems to be messed up and I am not sure how to select different stick mixing options.

  2. I have a turnigy plush 40 ESC which I calibrated and when I power on the plane it beeps unusually fast. Then I arm the plane though, I cannot get the motor to spin.

  3. I arm the plane with the RC transmitter, how can I disarm with the transmitter. I can’t seem to find which parameter I need to set to allow for transmitter disarm.

  4. I have a 3dr power module and I had to disable the power module pre arm check because it kept asking me to plug in the power module yet all my voltages read correct. The existing 3dr module works fine but PX4 does not recognize it?

  5. Is there a way to set the max wind speed, so the difference between ground speed and airspeed and then if the plane exceeds that threshold then it switches to using GPS speed only. This is to prevent crashes due to bad airspeed sensors. APM has this and it’s called AHRS_wind_max and it can save planes.

  6. What does land mode do on fixed wings

2

Hi Justin,

  1. After you have changed the orientation reboot your system and verify that the HUD looks ok and that changes made to the aircraft attitude are consistent with the changes you see on the HUD.
    Can’t see why it should change your mixing if that is correct. Additionally, you could also switch to manual to check that mixing is find because this is orientation independent.

  2. Do you have the motor connected into the right output? From the mixer table it looks like you need to plug the motor into the 4. main output (1-2 are servos, 3. is empty and 4. should be throttle).

  3. I think disarming with RC is not supported. Normally, when then plane is landed we just enable safety via switch which does the job.

  4. This is interesting and I will just open up an issue for that.
    https://github.com/PX4/Firmware/issues/4341

  5. Unfortunately, we don’t have this parameter. However, the airspeed sensor failure topic has been discussed a lot in the last weeks and we’ll come up with something for sure.

  6. Land mode does autonomous landing. We support using range finders to allow precise landings on a runway / field. Documentation is on it’s way.
    I’ll post the link into this thread as well.

Regards,
Roman

3

@tumbili

Thank you for taking the time to respond to my questions.

With the mixing when I am in stabilize and I point noise down I have left aileron down and right aileron up; however, all the transmitter directions are correct. Do I need to change my model type on my transmitter to correct that the old fashion way or is there a mixer parameter I can change to correct that?

I had the motor connected to output 3 which is the issue. Thanks for noticing that

The throttle disarm would be a great feature, not needing the safety switch because it is just another wire that adds to the mess and could fail. The transmitter arming and disarming is safe.

4

If you get differences in manual and stabilise you have the left and right aileron directions incorrectly AND you have changed your RC settings after you calibrated. Don’t do that.

  • Calibrate the radio and make sure to SELECT MODE 1 or MODE 2 in the top right selection
  • Switch the aileron servo connectors (if you have two) or set the PWM_REV parameter for the aileron channel in the PWM Outputs section of the params
  • We will never support disarm via RC, because a left turn with idle throttle would disarm the plane. This would be super dangerous.
5

Thanks Lorenz that is much appreciated, I am impressed by he level of support the PX4 team offers.

. Good points for the challenges with Rudder disarm. The disarm, I think it can be made safe like how APM does it where disarm can only happen when the plane is not moving. Some computer logic solves the issues very well.

6

Good point - my conclusion was drawn back in the time when we had no land detector. I have now allowed disarming fixed wing if landed on master.