Failsafe configuration for fixed-wing aircraft without GPS (Matek H743 Wing + ELRS)

General
1

Hello everyone,

We are trying to configure a failsafe on our aircraft but we cannot get it to work at all.

Our setup is:

  • Matek H743 Wing V3

  • ArduPlane

  • Mission Planner 1.3.83

  • Radiomaster TX16S MKII

  • RadioMaster XR1 Nano ELRS

  • ExpressLRS 3.5.2 on both transmitter and receiver

  • Fixed-wing aircraft with ailerons, elevator and rudder

The main issue is that we cannot get the failsafe to activate correctly.

We have tried configuring it from the radio side. On the TX16S we can find the “Set Failsafe” option, but it does not appear to save or apply the control positions we expect.

We have also tried configuring failsafe-related parameters in Mission Planner, but we still cannot get a reliable failsafe response when the transmitter is turned off.

At this point we are unsure if:

  • The failsafe should be configured in ExpressLRS.

  • The failsafe should be configured in ArduPlane.

  • The receiver should output specific failsafe values.

  • Or if ArduPlane should detect RC loss and handle everything internally.

Our competition does not allow GPS, so we are not interested in RTL or GPS-based recovery modes.

Before we can configure the desired behavior (motor off and controlled descent), we first need to understand how to make the failsafe trigger correctly.

Could someone explain the correct procedure to verify that failsafe is actually working with an XR1 Nano ELRS connected to a Matek H743 Wing V3 running ArduPlane?

What should we see in Mission Planner when the transmitter is turned off?

Any help would be greatly appreciated.

Thank you.

2

Arduplane generally doesn’t really support GPS-less operations. It is reasonably good at dead reckoning if GPS stops providing position but it wants GPS for normal operations.

What is justification for no GPS? Unless it is a competition about GPS-denied operations you should talk sense into the organizers.