Copter took off at full throttle in PH

[JussiH]

Can you post a log of the flight with the "take off" part. It might be saturation of your Zaccel from vibration.

[SuperSharpShooter]

Yep the log is at the bottom of the first post but here's the link again.

The first time in the log that it does it, the Z acc doesn't look saturated, but the second time, I don't know if the movement on the accs is as a result of the takeoff or the cause.

[bluuu]

it's similar to my problem: viewtopic.php?f=24&t=2312

It's possible to do a something like ... accz "peak guard" ? In this 2 similar events "jump" was incidentali and turn off pos/alt mode (for a while) solve problem

[bn999]

Under normal circumstances, you should not be able to saturate a 5g ACC sensor. If you do, then you have some serious vibration issues that must be addressed, ignoring them with software will not fix your problem.

The issue only "seems" to exist in autonomous modes as they are the only ones which give control of the throttle to the system. Estimate corruption is still going on no matter what mode you are in.

[JussiH]

Looks like Acc saturation to me. Balance props and motors..

[SuperSharpShooter]

OK thanks. Yeah this was on a recently converted hexa on which the props had been balanced individually, but not yet with the motors. Hopefully it will behave after a dynamic balance.

[SuperSharpShooter]

Have replaced the 12x3.8SFs with 12x6E's all round and it is flying much smoother now. Will probably look at going to Gemfan or APC 11x4.7s since it's still got a lot more power than it really needs.

[SuperSharpShooter]

Have just had it try and fly away again in PH with the 12x6Es (all brand new and balanced), it happened when I flew up high above some tall trees, and into a reasonably strong wind, which somehow set the vibrations off.

This is getting to be a big problem. It's been 6 months with this thing and I still can't even trust this copter for anything other than testing while I wait for some more different props to try.

I have the FC mounted on an aluminium plate, which is then attached to a lower delrin plate via squares of reasonably firm double sided adhesive foam that some gyros I have came with. Obviously it's not really working like it should. The GPS ground plane & antenna are attached to the frame separately so they won't make the FC platform oscillate.

[Max]

Have you tried just mounting the FC on short plastic standoffs right to the frame? From what I've seen, trying to isolate the FC on flexible mounts is often self-defeating. Then find what is causing the vibes (bad motor, prop, flexible arms, etc) and eliminate that. Once the FC is mounted hard to the frame, you can use the telemetry view/ACC plots to really tell what the vibes are, instead of guessing if the FC mounting is having an effect also.

My other observation is that your ESC signal wires seem stretched a bit tight. Ideally you want a small, loose loop of wire right before the connection to the FC, which helps absorb some vibrations transmitted via the cables. Old RC "trick" for keeping vibes away from the Rx. It can really make a big difference. A taut wire acts like a piano string, resonating at certain frequencies.

-Max

[SuperSharpShooter]

I did originally have the FC on short standoffs attached directly to the frame before trying any of the FC isolation methods.

The ESC wires look tighter than they are, but I'll try putting some more slack in.

I don't think the arms flexing is the problem as they are very rigid, but they are obviously transmitting the vibration from the props or motors without dampening it.

I'm beginning to think that maybe one of the motors is bad or needs a bearing replaced. I've noticed a small amount of play in one if I grab the tip of a prop and move it up and down. I'm not sure if this is from the bearings being bad, or the circlip just not being tight enough at the bottom. I'll try loosening the set screw at the top first and see if I can get the play out of it. I wont have any spare motors to try swapping for a couple of weeks. Need to pick up some replacement 2814-11 bearings to have on hand too.