It is either a power issue or a stabilization issue.
Stabilization problems can be:
- You must have "Zero The Integral..." ENABLED on the Configuration->Stabilization page
- Look to see that you have all the ESC signal cables plugged in, in the correct order, know which is #1
- FC mounted with arrow forward and ESC connections on the right side.
- Motors spinning in the correct direction AND with correct props on. Two wrongs do NOT make a right.
- bad calibration
- bad setup where you changed settings from default values and didn't put it back (because someone told you to)
Power problems can include:
- mixed motor types and some have less RPM
- ESC calibration and motor neutrals
- weight distribution
If everything correct:
Be aware that this procedure will run the motors with the props on, get a USB cable long enough to do this or use telemetry.
Unplug battery.
Plug in USB cable both ends and run GCS.
Very carefully use Configuration->Output page.
Play with sliders to get the feel for it and keep it in the lower part of range.
Start with the sliders all the way down.
Plug the battery in.
Press "test outputs".
You are testing one motor at a time
Move a slider up very slowly till the motor spins, then farther until it lifts a little
Make a note of the setting where it lifts
Move that slider to the off position
Test all motors that way
Are all lift numbers fairly close, say within 10% or 20% at worst?
ESC calibration and motor neutral setting. Do it once per aircraft / FC.
https://librepilot.atlassian.net/wiki/spaces/LPDOC/pages/12058743/ESC+Calibration