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Big X8 Strange Behavior

Posted by Antonis konstas on December 13, 2015 at 9:31am

Hello to all

I build a big X8 and i suspect some think happen with my rc mapping when octo starts it feels unresponce with big corrections and hard landings result and some flips whatever i do in P doesn’t affect the system so my next think is the rc mapping i use sbus futaba receiver direct pinned to pixhawk but my rc in and out in channel 12 and 4 look strange also the roll and dess roll looks opposite

I enquiry the LOG

Any comments are welcome

https://youtu.be/VW37goiZcRg

39.BIN

39.jpg

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Replies

- - - Antonis konstas > Antonis konstas December 17, 2015 at 11:03pm
      
      both is crashes with same setup difference between them 8 days and a new flight controller the big difference is in 24 log quad flies for one min smooth and problems start when i change flight mode and in last one i just try to fly to stabilize only the newest is at left side
      - Developer
        
        Randy > Antonis konstas December 17, 2015 at 11:36pm
        
        The 24 log certainly looks better. The main problem shown is that the pitch control is very bad. It's difficult to say what Rate Roll/Pitch P terms will work but there's a wiki page which shows how to use Ch6 tuning knob to adjust the tuning in flight. Big copters generally need higher P values so you might just try increasing Rate Roll/Pitch P from 0.15 to 0.25.
        
        If 39.bin is a more recent log then I think it would be best to go back and recheck the motors are all wired up correctly, spinning in the correct direction and that the propellers are on properly. It certainly seems like a mechanical issue though, not a software problem.
        
        Antonis konstas > Randy December 17, 2015 at 11:42pm
        
        Dear Randy
        
        First of all thank you for your time
        
        24 log it was the first crash 39 was the last crash as i mentioned the setup is the same only difference was the flight control due to old one it was defected in IMU so according answer form 3DR support we take a brand new FC this is the reason it is strange everything in the bench works flawless and it is very curious this machine is not fly i try to adjust pids manual via ch6 knob and then if this works i try to do autotune if this not work i suspect one or more esc is broken but i dont know how to examine them because as i say in the bench works like charm you can see video here from yesterday test
- Antonis konstas > Randy December 17, 2015 at 10:37pm
  
  randy i actually take off in 50% and at 1540 in throttle range in pixhawk this is very strange you think maybe esc are not calibrated correct in sbus configuration?
  
  I made now stand alone calibration to be sure everything is calibrated correct
Antonis konstas December 17, 2015 at 6:31am

pictures form electronic setup

DSC00306.jpg

DSC00307.jpg

DSC00310.jpg
Antonis konstas December 17, 2015 at 1:44am

Guys please this is a serious problem i ro know what to do
Antonis konstas December 14, 2015 at 10:35am

None can answer ?