so ive been dealing with this for like two weeks now and its starting to drive me insane. running a DJI RS3 Pro on a custom fixed wing setup, not a standard mount situation so i know thats probably part of the problem. did the horizon calibration like 6 times, followed the manual, watched every video i could find. it levels out fine on the ground and then once i get any kind of movement it starts drifting maybe 2-3 degrees to the left. not enough to ruin footage completely but enough that every clip needs correction in post which kind of defeats the purpose.

the weird thing is it only does it when im moving forward. hovering its totally fine. i thought it might be motor balance so i rebalanced the whole rig and it helped maybe 20% but still doing it. anyone dealt with this on a non-standard mount setup? wondering if its a CG issue with how ive got it positioned or if theres something else going on with the roll motor.

yeah the forward movement thing is almost certainly airflow interference messing with the IMU readings if its not fully enclosed. ive seen this on custom builds where the gimbal isnt shielded properly. the IMU is trying to compensate but its fighting wind pressure on the actual gimbal arm and losing. try adding some foam baffling around the base and see if that changes anything before you go digging into the PID settings.

also worth checking ? whats your follow speed set to? if its too high it can actually cause that subtle drift because the motor is constantly overcorrecting. backing it off a bit sometimes helps more than any calibration would.

not sure if this is related but i had a similar drift issue and it turned out one of the ribbon cables was slightly pinched and causing intermittent signal dropout to the roll motor. only showed up under load basically. probably not your issue if its consistent but might be worth checking if you've had the thing apart recently