a crash analyse

Posted by kevin zhou on June 17, 2014 at 12:59pm

It was a horrible crash with pixhawk and my new airplane. I dont get the reason. airplane get into spin and no response, and it wass too far to make a manuel control. it crash to a golf club almost make big damage.

Some one can help me with the log ?

a crash bin log

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Replies

  • kevin zhou June 25, 2014 at 1:18pm

    Please someone do help....pixhawk, with APM I never have this problem...

  • Carl Davis June 18, 2014 at 4:52am

    Can you upload the flight's telemetry logs? This resembles the "toilet bowl" affect caused by compass interference.

    • kevin zhou > Carl Davis June 18, 2014 at 6:26pm

      Thanks a lot for the help, I can not fly before I find out the reason.

      Here is the Tlog, just need to see from 90% of the log to the end. the beginning part is other flight before.

      I am using pixhawk onboard compass, I did not connect 3DR GPS compass module. It is better use that compass module ?

      One more question, why you need check Tlog? I suppose bin log on board have complete information, am I wrong ?

      2014-05-23 15-14-16.tlog

    • Carl Davis > kevin zhou June 19, 2014 at 2:14pm

      I wanted to look at the tlogs only so I didn't have graph in Excel.

      Dataflash log’s COMPASS message hold the compass’s raw x, y and z axis values (called MagX, MagY, MagZ) which are equivalent to the tlog’s RAW_IMU xmag, ymag and zmag fields.  It’s possible to calculate the mag-field length by first loading the dataflash log file into excel, filtering by the COMPASS message and then calculating the mag-field using the formula mag_field = sqrt(MagX^2, MagY^2, MagZ^2).  Note that the COMPASS message is not enabled by default in the dataflash logs because it runs at 50hz and does affect CPU performance a bit.

       

    • kevin zhou > Carl Davis June 20, 2014 at 9:59am

      Thanks for explanation. hope someone can help me to do some analysis on this issue.

      another is that GPS+compass module will be better than pixhawk on board compass ?

    • Carl Davis > kevin zhou June 19, 2014 at 4:28am

      Hi,

      I do not see the compass interference problems like those described at https://www.youtube.com/watch?v=4E0jKcuMRWA , but your problem sure resembles compass interference as described in the docs.

      Hopefully someone else can add some analysis to the discussion.

  • m00se June 17, 2014 at 9:22pm

    I'm sorry to hear that, I have been watching the crash list of APM for a while before I invest in a new skywalker 2013 and fit APM in it, Its a shame to hear about so many crashes, 

    All (or most ) of the ones that I have seen seem to be either stall related or the plane gets into a spin and takes a dive.  

    If someone can confirm that people are doing things wrong maybe there should be a sticky made to help us all prevent it. 

    Im glad no serious damage was done, sorry I cant help you with the log, 

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