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Violent Yaw during Ascent

Discussion in 'Phantom 2 Discussion' started by grrowler, Jul 1, 2014.

  1. grrowler

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    Firstly wanted to say what a great forum - so much helpful info on here!

    Have been experiencing a strange behaviour for a while, probably the last 4 flights (before and after I updated to 3.04) maybe longer. It is sort of intermittent and only happens during a straight ascent. Rest of the time it flies fine.

    Being quite new to the whole thing I presumed it to be operator error, and it still could be, but thought I would check on here anyway.

    Today, a few times while climbing at about 1m/s, the P2 yawed quite violently, probably around 45 degrees, sometimes less. I think it is always left, but I need to check on further flights. I instinctively centred the stick and it immediately stabilised, and I could resume my climb. It sometimes happens in the initial lift off, so it ends up about 3ft in the air but facing even 90 deg off. To me, it seems like it is getting a fistful of yaw input, and that's why I thought I might have been accidently moving the stick left slightly, but today I am fairly certain I wasn't.

    Anyone seen this before?
     
  2. IrishSights

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    Yes this did happen to me once about a week ago on take off. I put it down to just me unintentionally introducing yaw on the stick on throttle!
     
  3. grrowler

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    Possibly that's the case, not sure I'm convinced though. Anyway I'll work on my lazy finger and see if it goes away.
     
  4. EMCSQUAR

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    Try this - go into assistant software -> Basic -> RC and re calibrate the sticks, then goto Tools and do an advanced calibration on a perfectly level surface. Then before next flight do a compass calibration.
     
  5. grrowler

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    Just fitted my FPV so did all calibrations after that. Have always done them regularly. Also do a compass cal before all flights. Hopefully I'll get a chance to go for a fly again soon and take more note of what exactly is happening.
     
  6. grrowler

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    UPDATE: Still having the issue but thought it was my lack of flying finesse. Doing a calibration today I noticed something strange which confirms my suspicions. Plugged into my RC Assistant and gave my sticks a swirl, and noticed that when the T channel (up/ down) value gets to approx 700 up/ 500 down, the R channel goes crazy and shows full 1000 Left! Absolutely not inputting accidental yaw on the stick.

    I've recorded a video which I will re-attempt to upload shortly, but surely that is a faulty TX?
     
  7. grrowler

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  8. mr.goodkat

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  9. grrowler

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    The video was taken immediately after a calibration. Just to be certain I just did another cal and the problem remains.
     
  10. grrowler

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    Can anyone with more experience confirm that the indications I'm getting are a fault? I'm surprised this has never been seen before. To me, any calibration would just use the garbled inputs and calibrate that, which would remain incorrect.

    I have emailed dji and of course received no reply as yet, and the Australian tech support number doesn't answer.
     
  11. OI Photography

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    If those values you posted before were seen in the RC Assistant and not the P2 Assistant, and the calibration there doesn't resolve it, you have bad hardware.

    Have you contacted the dealer you bought it from?
     
  12. dazzap

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    If you dont have any luck I have a spare controller due to my phantom disappearing into a sugar cane field. You can have it for a good price if your interested.
     
  13. EMCSQUAR

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    After seeing your video - I suspect your TX is bad. You can take it apart and inspect your left stick control for loose or misalignment. Or bind another TX to confirm. If it's not that old contact selling dealer.
     
  14. grrowler

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    Been away for a few days, thanks for the responses.

    DJI also suggested I do a calibration, which I did just to be certain, and the problem still exists.

    However, I believe I have found the cause. I opened my tx and on inspection found that a yellow wire running to the left stick was pinched under the screw holding the curved silver springy bracket thingies (? :)). This meant the wire has been shorter than required and has put the solder joint under tension when up or down stick is applied. The wire is only being held in place by the white silicon over the solder.

    I've never been inside the transmitter before so looks like dodgy quality control by dji. It's under warranty so it's off for repair.

    Thanks again for everyone's input.
     
  15. noiseboy72

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    There can be an issue with dry joints on the control board. This momentarily disconnects one side of the control pot, causing the outcome you describe.

    To fix, you need new hardware, or a few minutes with a soldering iron to re-flow the solder around the pins.

    I think it is due to board flexing around the gimbal control.