Hello, I have a plane with a v-tail and I do not find in QGC how to activate the mix between track 2 and 4. Can you help me? Thanks
You should ask the firmware folks.
The albatross (airframe id 2106) is an A-Tail, but it's the same mixing.
If you want something more specific for your vehicle you could add a new configuration. Start by duplicating the Albatross. https://github.com/PX4/Firmware/blob/master/ROMFS/px4fmu_common/init.d/2106_albatross
Mixer documentation: https://dev.px4.io/en/concept/mixing.html