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[CRASH] X8 and APM 2.5

Posted by Antoine Lagarde on November 13, 2013 at 2:48am

Hi everyone

I had an unexeplained crash with my X8

Here are the specs : 530kv motors with 14 inches graupner props

APM 2.5 with 8 20A escs

So what happened, I was trying my new retractable landing gear on channel 6.

I have channel 5 configured as flight mode

I had maybe flown 2 hours with it before with no problem at all

I flew great for like 30 seconds, opened the retracts several times and closed them, then suddenly it started to bank left slowly (as you'd expect with 14 inches props and slow motors) until it crashed half way before going upside down.

I have no idea what caused this, it was flying good then for no reason bam crash. I know no motor or esc stopped and even if it did it shouldn't be a problem as APM 2.5 can use the X8 redundancy

The ONLY thing I changed between my no problem flights and the one with the crash was that I switched from one wire ppm to several wires pwm (to support the landing gear that can't deal with ppm). But then again it flew ok for 30 seconds.

Any idea on things to check cause I don't want it to happen again 

Thanks

Antoine

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Replies

  • MR60
    Hugues November 25, 2013 at 10:52pm

    Antoine, how are your retracts powered?

    If you power them from your receiver or APM you will create a brown out of APM and crash. You have to power your retracts by an independent BEC from the battery ( or by a BEC of your ESCs).

  • Antoine Lagarde November 25, 2013 at 10:42am

    Ok so I changed the many motors taht were destroyed in the crash and went for another try..

    I flew and again after a little more than one minute the x8 litterally turned off like the first time and flipped to the ground.

    I've isolated what's causing it, but I have NO idea why it's happening.

    I have retracts on my multi built with servoless retracts from hobbyking. First time I tried to use them was on the first crash.

    I took off, tried to retract them but one would not go up. So I put them down again, then tried to retract them, again only one going up, and then bam, the x8 goes crazy and flips to the ground. Same behaviour after the exact same sequence on the two flights ! On the second flight the APM stopped logging when the x8 went down as if it was litterally "turned off".

    Knowing that my retracts are connected only to the receiver via pwm and not through the apm, I really don't understand this at all

    Does someone have a clue please?

  • Antoine Lagarde November 18, 2013 at 1:49am

    No one knows what I should/could check ? :/

  • Antoine Lagarde November 15, 2013 at 1:23am

    Ok, one question then, is it possible that the fact I changed from PPM to PWM caused this in any way ?

    Thanks

  • Antoine Lagarde November 13, 2013 at 2:34pm

    here is what I found looking at the logs. At the moment when the crash happened (when the quad started to bank left and almost upside down until crash) the YAW went crazy up for no reason and followed the altitude curve

    ALSO, as said the quad went upside down on the roll axis to the left, so there should be traces of it in the log, roll sensor going crazy etc etc and even more at impact (arround the 2000th line of log)

    So I don't know what I did wrong and if I even did anything wrong on this one

  • Antoine Lagarde November 13, 2013 at 12:53pm

    Ok ! here are the logs of that flight

    http://s000.tinyupload.com/?file_id=00462091409339393298

    thanks

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  • Andre K. November 13, 2013 at 10:31am

    you NEED to post logs, if you wish any help.

    It's impossible to help you whithout.

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