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  1. gyrex

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    Hey guys,

    I know this is a fairly common issue with the P4P (never had it with my P4 or P3A) and I'm on my 2nd P4P with this issue of the craft not flying in a straight line. Has anyone been able to solve this? It makes shooting videos insanely difficult because it requires 'straffing' the craft in order to keep it on line. I do not want to send my bird back for repair since this would be the second time on my 6 month trip around Australia and last time it took them 3 weeks to 'repair' my old bird which suffered the same issue as well as major cracks in the shell. It almost always flies to the left which is what other P4P owners have also indicated so this is either a software or hardware issue with commonality amongst other P4P owners. Does anyone's P4P fly straight?
    Things I've done to try and solve this:

    1. Performed cold IMU calibration (many times - maybe 20 times)
    2. Performed compass calibration
    3. Performed controller calibration

    Compass fine

    [​IMG]

    IMU fine after cold calibration

    [​IMG]

    Nothing has alleviated the issue thus far. Has anyone else solved this?

    Here's a link to a video showing this issue. You can see I've aligned the P4P up with the straight road and it flies off in a diagonal direction. Flight log here: DJI Flight Log Viewer - PhantomHelp.com

     
  2. Brimba

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    make sure camera is pointing straight before takeoff.
     
  3. gyrex

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    It's straight.
     
  4. Yeadonites

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    Location:
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    Are you in GPS or ATTI? Would it do this if you used waypoints mode?
     
  5. gyrex

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    P-GPS mode.
     
  6. Cajuncontroller

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    I know that the GPS corrects for winds, but what was the direction they were coming from and how strong were they? Noticed a high wind warning at the beginning of the video and it appeared to be an onshore breeze just from looking at the trees. Might be a contributing factor.
     
  7. JoBe

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    a thought maybe check your flight logs to see if you are giving some stick that you dont realize?
     
    Oso likes this.
  8. gyrex

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    The stick was locked in straight. In order to follow a straight line, I need to push the stick almost into the corner (roughly 35 degrees to the right from centre).
     
  9. Skynet1

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    I've deleted my last posting as I somehow overlooked you had already performed a controller calibration with no success. Not sure if you've already mentioned whether you had performed a similar test under mild wind conditions, as other have already pointed out what appeared breezy coastal winds during your test flight. You may then be in a better position to get a more precise feel for just how much drift you are actually experiencing.
    Other than that, all your other calibrations appear very good. I can't say I have experienced any such issue on my P4P as you have on two different models.
    I'd simply be speculating to say there may be an rpm variations associated with one of the motors causing the model to drift left, not sure. Regarding cracks, there have been reports of unusual vibration on some AC suspected to be result of updating to a specific f/w version, not sure now which one, however, structural cracks followed shortly thereafter as reported by some. Those affected ultimately decided to drop back to a previous version f/w to offset the issue. Sorry I'm unable to provide a solution.
     
    #9 Skynet1, Apr 12, 2018
    Last edited: Apr 12, 2018
    JASKJosh likes this.
  10. StanMI

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    Maybe time for new props ????
     
  11. sar104

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    You will need to examine the log files to determine what, exactly, is happening, and what the FC thinks is happening. Otherwise it's just guesswork.
     
  12. Stach

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    My P4P drifts slightly off center as well, so I found this fix in a DJI forum. I haven't tried it yet, as I'm not exactly sure what the fix is that they are describing. Hopefully somebody else can spell it out exactly and see if it works, as I would like my P4P to fly the same straight way my P4 does. Here's their fix...

    "Constantly making a rudder correction while trying to fly straight because the gimbal was off. Finally fixed it by doing the gimbal calibration routine while the aircraft is held perfectly vertical and only sitting on the rear arms and not the landing skids. You’ll have to hold it in that position. Worked perfectly. Camera is straight for the first time."

    Good luck!
    Stach
     
  13. AndrewCCM

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    Yea... That is definitely not right... My P4P doesn't fly like that... I haven't paid attention if its perfectly straight, but I certainly would notice your phenomenon...
     
  14. ETC

    ETC

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    My P4A flys at a 5 degree yaw so I just compensate for this while using litchi. I tried tweaks, IMU cal and compass cal but it still flies a bit off.
     
  15. Bob62

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    I am not a expert at this but it would appear you have a fairly good on shore flow of wind, I am watching the black flag in the front yard of one of the resident dwelling. Your drift is to the left
     
  16. gyrex

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    It had nothing to do with the wind. The bird should fly in a straight line regardless of wind since it's using a compass and GPS to track. The issue was the camera wasn't aligned correctly. No amount of IMU & gimbal calibrations could fix it until I found a bizarre hack - calibrating the gimbal with the phantom vertical and resting on its rear motors, that fixed it.
     
  17. Bob62

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    Thank you for the information
     
  18. Skynet1

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    Glad to hear you ID the issue and performed the proper gimbal calibrations. I don't know that the gimbal calibration you eventually performed to get the model sorted may be considered a hack, as I believe this is the most recent method DJI suggests to calibrate the gimbal, and the steps are actually demonstrated via the Go app.
    I suspect those who had responded had presumed you were familiar and performed those calibrations accordingly. Fly safe! : )
     
  19. gyrex

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    This is the alternate/hack gimbal calibration that fixed it. Note the phantom resting on it's rear motors and it's facing in a vertical position:
     
  20. AndrewCCM

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    Did that the first day I owned the P4P.
     
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