Crash while stabilized mode

Hi Folks,

Today I flew my X8 wing in manual mode to get it perfect trimmed (done). It was flying like a dream. My second step was to change to stabilized mode, but when I switched I noted that plane did not keep level and right wing dropped drastically getting into stall. No time to recovered and it crashed.

Even if I followed ground calibration as recommended, something was wrong. Now my main doubt is about level calibration. It was no clear how to do it ( 1 axis ? , 6 axis ? just one time or every time before a fly ?  How critical is it for stabilized mode?  Is there a clear and easy procedure to follow?

I was using APM 2.6 , airspeed sensor, 3DR telemetry, 3DR power mod, latest arduplane firmware...

Attached is tlog file ( valid data after 60% of time scale).

Comments are welcome.

Regards AA 

2013-08-25 12-22-45.tlog

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  • Have had set up a couple different auto pilot systems and having had made my share of errors in setups... it sounds to me as though you may need to "up" your test altitudes...  I had a $1000 airframe do a 90º nose dive at 50knts upon the first activation of one such system..  had I been anything other than 400' agl, it would have been all over...  had plenty of time to turn off the system, recover from the dive and collect my wits...

    Always provide plenty of room for error when testing new stuff (all new stuff is presumed to be screwed up until proven otherwise)

  • Thanks a lot guys for your comments I really appreciate them !

    As soon as I have my X8 repaired ( fortunately the damages are minimum ) I will recheck  "leveling" and "surfaces movements with stabilized". I hope that parameters and everything programmed in the APM have not changed after the crash.

    Coming back to the recommended ground calibration doc.

    it was clear to me that all these procedures must be followed just one time after you install the APM and setup all your parameters( In fact the title  of the document is : "First-time flying checklist" ). If my understanding is not correct, I would suggest to editors so please improve the wording. A clear and pragmatic wording will make easy our life. 

    I'll keep you informed ..

  • Your log stop recording at an altitude of 32m!?

  • Developer


    In newest release you need to manual level the plane. Older release would always level on boot. The docs look like the 

  • It sounds like the elevon control was reversed. When you set up your aircraft did you hold it in your hand and roll/pitch while in stabilize mode to watch the flight controls and make sure they were not reversed.

  • Can you confirm your aileron movements in stabilize mode? It might be reversed.

    The plane should be leveled for the first time and it doesn't require to be calibrated every time you fly.

    Well you need to re-calibrate you radio with APM after you trim your plane and then try stabilizing your plane in stabilize mode or you can enable auto trimming if you want to do it during flight.

    For me the best and easiest way to level your plane is to go to terminal in your MP. Connect APM. Enter into setup and write Level and enter. it always works for me :)

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