I am using Cube Black with Ardupilot. When the drone flying in high speed, it could not hold it altitude, gradually descent and finally crashed to ground. Also in windy situation, the altitude is not stable, if strong wind blows, it descent and ascent when the wind stop.
The parameters on the CubeBlack need to be configured so that they match your specific airframe.
You need to read the documentation and follow the tunning instructions.
Is it Airframe Setup and AirSpeed Calibration in this page?
I already set up the airframe in MissionPlanner. And I don’t have airspeed sensor for my drone. Is there anyelse setting to tune?
It is a custom tether drone project based on official Ardupilot 4.0.3 firmware. Only few mode is customized (follow mode in this case) and most of the other code remain the same.