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2 crashes on 2 consecutive flights, why?

Discussion in 'Phantom 2 Discussion' started by tomic, May 5, 2014.

  1. tomic

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    I've been reading on this board for weeks and have learned a lot, but i havent read a situation quite like mine.

    Been flying for about six weeks without a hitch until last week when I was flying GPS in a field, all was good flying for about 2 minutes until my phantom started to turn and go full throttle in another direction on its own. I still had control and was able to steer it back into my general vicinity where it crashed, unfortunately camera was not recording.

    Took it in to my local dealer who fixed it up, he checked the motors, GPS, compass, put a new shell on her. He tested it and it flew well when I came to pick it up.

    Brought it home went to another field, no gimbal this time, different controller (stock instead of futaba 8fgs) and again flew well, hovered well, took her up higher and then just like the previous crash, 2 minutes in it started to go full throttle to the left on its own, tried to flip to atti but it was too late. It ate the ground full throttle.

    What is happening with my p2?
     
  2. EMCSQUAR

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    Not knowing how your dealer "checked motors, GPS, compass..."

    Try doing advanced calibration in assistant software, then calibrate sticks, then do a compass cal/dance.
     
  3. kgarrison

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    Are you flying near any high power lines or large antennas?
     
  4. tomic

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    Did all of the above before the 2nd crash

    Kgarrison, there's no power lines or antennas for at least a mile radius
     
  5. EMCSQUAR

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    What kind of numbers are you seeing at "compass mod"? Ideally they should be from high 1200's to low 1700s is acceptable range. If they fall outside of those #s you might have to defrag compass using a magnet (there's a video from DJI showing how to do this)
     
  6. tomic

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    The mod was good (1500)

    I think its odd thing is that it flies fine for a couple of minutes and then just goes full throttle on its own.
     
  7. ianwood

    ianwood Taco Wrangler
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    We need to see a video. Hard to tell what is happening without more data. Ideally one that shows normal happy flying and then where it goes wrong and the aftermath.
     
  8. FLGulf

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    Does your Phantom have vibrations? unbalanced prop(s)

    When reading about how to read a telemetry log on another brand, it said:
    VIBRATIONS: cause accelerometer based on altitude and horizontal position estimates to drift far off from reality.
    Leads to problems with altitude hold: (Rocketing into the sky) or Loiter (drifting)
     
  9. Supa

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    I had a similar situation. I had many problem free flights with the P2, H3-2D gimbal, and stock controller. I had been taking off from an area with a significant amount of metal and had been having issues calibrating the compass between flights taking off from the same location. Unfortunately, it was the only location I could take off and land from.

    During two of the flights, the P2 started circling with the front staying to the front. Then the P2 snapped hard left. I was able to bring it back right eventually, but it snapped full right and I decided to drop it immediately into an open area.

    No high voltage lines in the area. I had chalked it up to the compass issue I had been having.

    Does this sound somewhat like what yours did?
     
  10. tomic

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    Yes sounds very much like my situation, I have been having a hard time calibrating after lifting off (once) from a metal table.

    That was about 8 flights ago, I have recal'ed the compass, checked it in the assistant software and calibrated the sticks since then

    Could I have a faulty compass?
     
  11. ianwood

    ianwood Taco Wrangler
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    Do not calibrate near any metal. Do not take off from large areas of metal. The compass is very sensitive. Only calibrate it out in the open (e.g. in a field of grass) away from pipes, gratings, metal plates, etc. And taking off from large metal objects is a known cause for flyaways.
     
  12. madsonp

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    s the area you're flying from a concrete pad that has a lot of rebar or wire mesh in the concrete ? This can also affect things.
     
  13. Northwest_Scene

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    https://vimeo.com/92949561
    https://vimeo.com/92949561

    Heres a captured video of how your crash was similar to mines. Just full throttled al th way and no time to switch to atti mode.
     
  14. Supa

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    Technically, it was a flat rooftop one story up with pipes running across the rooftop here and there and metal bars to keep people from falling off.

    It certainly wasn't an ideal take off/landing area.
     
  15. tomic

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    I went back and did all the calibrations and went out flying.... again the p2 drifted in one direction but i was able to bring it back and land it safely. I came home and checked the motors and AHA! i found that the right front motor pulls (see video)

    I think this is whats causing the drifting (?)

    [youtube]https://www.youtube.com/watch?v=I9F5JCKyJbo[/youtube]

    I have 4 replacement motors, the question is, should i replace all 4 or just the 1?
     
  16. tomic

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  17. The Editor

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    Looking at that video and the amount of play you have in that motor housing I would say you've lost an e-clip !

    Remove the motor and check underneath
     
  18. Pull_Up

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    +1 on that diagnosis!
     
  19. ianwood

    ianwood Taco Wrangler
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    The e clip on the bottom of the motor has come off. Not uncommon after a decent crash. If it's still there you can put it back on and then retest. Note for everyone, when you have a crash, check for vertical and horizontal play and smooth turning of the motor bell housing.
     
  20. tomic

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    thanks for the reply guys

    what does the e-clip look like? and could this be causing the drifting im experiencing?

    Also, if i cant find the clip, should i replace the motor?