3691029722?profile=original3691029807?profile=original3691029864?profile=originalI am sure that this topic is getting beat to death but i can't find a working solution.

my bird is a 76 cm Hexa with the APM 2.0. It has 1000 kv motors with 10.5" props. It flies great in stabilized mode but when I switch to altitude hold it slowly descends and then shoots up a what sounds like full throttle.

I am using sonar and I believe that I have my vibrations well within tollerance.

I have been trying to get it to work properly by changing the throttle accel settings but to no avail.

I have included a log file and a couple of pics of my bird. It's been a build going on for about a year but im still to nervous to put on my FPV gear.

It's outfitted for night flying too.


2013-06-10 18-48 6.log


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  • just to go to the interesting thing, i get nice altitude hold (soft 3.0 rc6) for a while, ad it goes full throttle at random moment. I had 3 min hold and throttle up then and also a 7 min alt hold before it tried to fly away... 

  • Thank you for the replies and suggestions. I've got rain for the next five days now but as soon as it stops I will disable the sonar and try again. If that works, where would I go from there?
    Jan, I will lower my throttle mid more and yes the spikes are landing.
    Thanks again.
    I am open to other suggestions as well while I'm waiting for the rain to stop.
  • Barry,

    I had a look at your logs and at first sight it seems that your average throttle is about 361 which means that you are under the deadband limit (40% - 60%).
    I saw that you already reduced the Thr_mid to 480 but I would suggest to lower it even more to match your hoover throttle (370).
    It is no issue of vibrations as your AccZ seems fine except for 2 spikes but that must be due to landing I supose.

  • T3
    Super build. I'd also try without the sonar.
  • Have you tried without sonar?

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