Lost control and got a hard landing


I finished building my quad on a Tarot 650 sport-frame and have taken it for two flights. On the first flight things went fine, but Loiter mode made the quad initiate a fly-away, but I stopped it by switching back to alt-hold-mode.

A few days later I was taking it for a second flight. Before launching it I did a new live calibration of the compass in hope that it would fix the issue with it trying to fly away, but it was still the same. However after switching back to alt-hold-mode the quad suddenly do a fast descent from about 7m and went into the ground. The battery got disconnected in the impact, and one of the carbon fibre tubes for the landing gear broke.

I wonder what might cause this quad to have issues with loiter also after the successful compass calibration, and even more I wonder what happened when it suddenly went into the ground. I’ve been trying to make sense of these logs in MP. I can see the gyro going crazy in the impact, and at what times I’m switching between modes, but can’t make much sense of why it went into the ground.

Would someone at this forum be kind enough to see if there is some logic explenation for this in the logs? Thanks a lot in advance.

Pictures of the quad

Best reg.

Looking at the log, it looks like you have high vibrations. This is the usual cause for poor alt hold and loiter performance.

That is probably right. I have not balanced the 4108-380 motors, and when I took of the propellers and gave them a spin, I could feel massive vibrations on the arms. Those motors are very unbalanced.

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