I made a Hexacopter (APM2.6 w/external compass: AC 3.1.3 installed) and I’m sure there are no calibration mistakes. The problem is, when I spin the motors, APM itself decreases some PWMs and increses some. This is mostly to yaw but sometimes it can pitch and roll too. When I decrease all the PIDs to 0, the motors all spin at the same RPM.
What do you think? Compass issue?
Update: I raised the compass about 20cm high, re-calibrated and carried out compassmot showing 4% interference. But the yaw degree on the mission planner increases constantly without a touch to the transmitter. Please reply, I have to fix this.
Check that all your motors are corrected in the right order, take the copter over grass, throttle it up and see if it lifts off level. The motors will never be perfectly even when you throttle up on level ground. The only time they will ever be perfectly even is when they are all at minimum.