Quadcopter pitches backwards and stops when releasing stick instead of drifting forward


I’ve searched for somebody having similar behavior and suggestions without much luck. I’m running:
Ardupilot Flight Controller 2.6 with Arducopter 3.2
Symmetrical X layout quad with COG centered

When in Stabilize or Alt Hold mode and in a forward flight, releasing the stick will cause the quadcopter to pitch backwards and come to an abrupt stop. I’ve tried turning down the Pitch Stabilize and P gain without luck.

I have a TBS clone with the Ardupilot 2.8 FC that does not exhibit this behavior. When I release the stick, it keeps drifting forward with it’s momentum.

Any ideas on what to try?


Could may be vibrations or something. A log of the flight might help see what the copter things it’s doing. You may have to turn up the logging value so we get the information we need. I think the default logging is 830 which is too low.


50 12-31-1969 5-00-00 PM.bin (457.4 KB)


I turned on most of the logging and did a quick test flight. I tried it with a smaller battery to see if the weight would be an issue. Although less pronounced, the behavior was still there.

I first tried to reproduce this in Stabilize mode. It was a lot better with the smaller battery, but still slightly pitched backwards and kept a little momentum.

I then switched to Alt Hold mode and tried it. It very noticeably pitched backward when releasing the stick and kept very slight forward momentum.

I uploaded the .bin logfile for review. Thanks for your help.


Well this is a little outside my area of looking at logs. I can see that the copter is a little heavy on the back side. I can see that motors 2 and 4 are working harder to compensate for this. I also can see where when you release the stick that there is a overshoot to pitch the copter back up right.

Either motor 1 or 3 bottoms out when trying to level out after a forward movement that may be causing the sharp pitch up at the end. Anytime the motor go to max or min the copter is out of control.

You might want to try flying in different direction to see if happens in all direction or only just going forward.


Hi Mike,

Thanks for taking a look. I’ll try balancing the quad out and see what happens. I guess I have a few components are the rear that throw off the balance. There are GPS/mast, power plug, wiring, and voltage monitor.

It only does this when moving forward so that makes sense. I’ll have to take a look at the logs and learn how read those parameters. I didn’t realize you could see. How much each motor is working.

Thanks again.