Strange flip during flight

Hi all,

Today I was flying my copter (GAUI 330/APM1/v.2.5.5 from MP) and suddenly it made a very strange flip/roll. Luckily I had some height and the copter stabilised after e few seconds but this was quite scary. Before and after this moment everything was as normal.

I had just taken off and was doing a fairly high speed forward flight agains the wind. It was quite windy (10-15 m/s). 

If you look in the attached log, you'll see that at around lin 15740 there is a large spike in the roll value.

Can anyone comment on what might have caused this? 

2012-05-26 19-42 16.7z

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –


  • @Gerrit I'm happy you solved your issue, although I still suspect there is something hardware related.

    I recently had a friend witth a gaui x-s that had strange behaviours with yaw. It turned out it was the motors connectors were getting desoldered (they are really crap and too small IMHO). 

    Regarding throttle calibration I don't think your solution will be pratical because you have to connect the battery while you keep your sticks in a certain position.

    A good practice is to alway check your radio before attaching the battery. A full throttle is quite visible. :)

    And if it does not boot the first time, a suspect something is wrong should be your first thought.



  • wow! I had this exact same thing over the weekend. From my point of view, it went inverted, backwards.

    I was in rather quick forward flight and came to a slow stop (backed off on the throttle, not harsh) and it seemed to over-cook the stopping process. The back fell "underneath" and the front came over the top. I froze, expecting it to tumble but in a panic I gave it a bit of throttle and it recovered itself. Flew around for a while longer without it happening again.

    Had some aggressive flying before and never seen it do this.

    I can submit my log tonight when I get home if that helps.

    3DR quad X config, APM2 2.5.5, with sonar, 850Kv motors



  • @gemit, all

    There has been a recent fix to the code for throttle management.

    The fact was that the controller was giving full throttle leaving no space to manage stability.

    This is in part (probably) what was happening to you, but there could be other reasons. Infact it never happened to me and other devs. Probably your setup is reaching it's limits in terms of weight, and/or wear.

    Reading better your last post I understand you are using the OLD gaui 330x with black motors (and under rated 6A ESCS). This setup was well underpowered and had different issues concerning ESCs, often burning because of too high current needed by motors. This is why soon after the first 330x (that I currently own) the 330x-s with 10A ESCs and Scorpion motors was launched. If this is the case, you should consider changing ESCs or not to fly with high load and at maximum throttle.

    @Alvin I doubt this problem is affecting you, yours seems more a configuration problem. Be sure you have entered correct value for tuning and that you don't have any strange values when you connect to the planner.



  • I have had this happen to me too...  I was not even at full throttle but at "fast climb" and I would get a hard roll over.

    gonna see if I downgrade and try it see if that clears anything up.

  • OK, i have some footage of a flip now. This basically happens everytime I suddenly increase the throttle to full. When I don't do this, there seems to be no problem at all. If I hold the quad in my hands and give full throttle it doesn't do this. I have attached the log of this flight. 

    It's a little bit hard to see but the copter is flying with the back (blue legs) toward the camera. It flips backward (yellow legs up) everytime I engage full throttle. The actual flip you are seeing on the attached video is the third peak in the log.


  • I've started test flights todayon a R550 hex. The first couple of takeoffs were nice and the default values were stable enough to watch for a while before tuning. I then got a flip on takeoff. I went back out this evening and got another flip on the first takeoff attempt. My takeoff is a slowly increasing throttle. Takeoff occurs at about half throttle as expected. Any ideas would be appreciated. I don't like the idea of Russian Roulette each time I advance the throttle.

  • I reply to my own message, I got the same thing today again. I never had this before 2.5.5, so could this be a problem with the new software?

This reply was deleted.


David Hori liked Isabella Domi's profile
Jan 12