How do I add my own custom airframe?

If you add your own custom airframe to the build and build the .px4 file and flash it (e.g. through make upload px4fmu-v5_default) it will be fully configured, but the meta information for it has not been provided to QGroundControl. To store the meta information in QGC you need to flash .px4 file through it - go to Firmware Upgrade, select the autopilot and PX4 and select “Custom File” instead of the latest PX4 version.

As mentioned in the developer guide Adding a New Frame > Add New Airframe to QGroundControl

Hello!
There is still some lack of documentation for adding custom vehicles to PX4 SITL simulations. However, many such discussions exist on the forums. Having faced this problem, I’ve compiled documentation for this process and would be happy to send a PR to the main PX4 documentation itself. Do suggest any relevant changes you think I should make to this.

@Jaeyoung-Lim