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Suddenly not stable

Discussion in 'Phantom FC40 Discussion' started by Kwas, Sep 1, 2014.

  1. Kwas

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    I have had my FC40 for 3 months now. It had performed very well and everything has worked as it should. But now a problem has surfaced. It is no longer stable. Now when hovering it bounces around a lot, letting it hover it moves around much more than it ever did, a slight breeze will move it and it may or may not come back to where it was. A stronger gust of wind will not only move it but it may turn on its horizontal axis and stay there. When attempting to rotate it in place it will move horizontally quite substantially. I calibrate the compass every time I fly it. I also always get more than 6 satellites and a home lock.

    The latest firmware is installed. I have done a basic and advanced calibration several times without any improvement. I have installed new props without any improvement. I have calibrated the sticks numerous times. I have done everything that I can think of to no avail. Any help would be appreciated.

    Thanks, Kwas
     
  2. EMCSQUAR

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    Go to Tools page of asst software and reload default settings then do advanced IMU and compass calibrations.
     
  3. Kwas

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    Have already done that with no change. One other thing, it is not vertically stable either, I used to be able to let it hover about 6 to 8 feet above ground and it would just sit there forever, now it will go slowly go up or down rather than just sit there.
     
  4. Lonewolf

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    You're using civilian GPS, not military GPS which would be spot on. Civilian GPS allows for drifting up to a 6-8' diameter. As for vertical drift. Could be power fluctuation or, down draft from the props.
     
  5. Kwas

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    As I said, it would sit there forever without moving, something changed.
     
  6. pert

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    have you checked to make sure naza is glued in place, mite have moved
     
  7. Lonewolf

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    Really? Sorry, but according to physics, that is physically impossible. The slightest air current will move it in any direction. If it's as bad as you claim, you should try using EMCSQUR's advice. Reset it to default settings, then do a compass recalibration and advanced IMU. If all else fails, check the magnetic declination for your area. When setting up my compass dance, I ALWAYS point the front of my Phantom to my magnetic declination point then turn in a counter-clockwise rotation so as to get a good compass calibration. You might also want to check for GPS satellite prediction. Just because it says it locked onto 6 satellites doesn't always mean it holds onto those 6. Lastly, check your compass to see if it needs degaussing. It may be completely out of whack because it came into contact with a strong magnetic field.

    Goto: http://magnetic-declination.com/ for your area.
    Goto: http://satpredictor.navcomtech.com/ for desired GPS satellite prediction for your area.
    Good luck...
     
  8. Kwas

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    I have not but do intend to open it up soon. I think that it would be the GPS that may have become unattached rather than the naza.
     
  9. Kwas

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    I appreciate you being sorry but it is obvious that your Phantom has never been as stable as mine and others have been. Mine would hover without any detectable movement at all with little or no breeze. How do you do a compass calibration, the only place I see it is within Advanced calibration, it that what you mean? I have never paid any attention to direction or declination when doing the compass dance and have always used a clockwise direction without any problems. I have no idea how to tell if it is losing satellites. What is the proper method to degauss the compass? It has never been around any strong magnetic fields to my knowledge. As I have stated, this all came about suddenly and I don't think that the way I prepare for flight has anything to with my current problems.
     
  10. Lonewolf

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    [quote="Kwas"
    I sincerely doubt my Phantom is no less "Stable" as you call it, than any other one out there. I'm not saying it drifts all the time, but at times she will. And that is normal. Many on this forum will tell you the same. Drifting as you claim are attributed to natural and physical variables. Wind/breeze, loss/weak GPS/GPS variances which allow for 6-8' drift while airborne, incomplete setup, incomplete/defective compass calibration or, defective components. For example, when using a handheld GPS you will very rarely achieve an exact return to a waypoint. You'll be within 3-4' of it. Why? Because you're using the civilian GPS.

    Magnetic declination varies and changes. Using the URL I provided before, find yours. Then when doing the compass calibration point your Phantom at that point. Then do a counter-clockwise rotation for both settings. Many times when your craft drifts or wobbles as if it's in a toilet bowl flush that is the reason. You didn't achieve a good calibration.

    Allowing the compass too close to a car stereo speaker while getting in or out of the vehicle can cause you problems.

    Deguassing the compass requires a magnet and setup to your NASAM assist software. It's best to first watch how it's done on YouTube before you cause any more damage to the compass. Or find with the NASAM it was fine.

    You might have a defective GPS receiver. If you carefully open the Phantom you'll see it on the top cover. It's a delicate ceramic and is easily cracked or broken if it was involved in a hard impact "TOP" style crash. (An inverted top over crash/impact).

    Lastly, check your motors. One might be running slower than the others causing you to be unstable. Most reliable hobby shops can check them with a tachometer.
    Best of luck, and hope you figure it out.
    Lonewolf
     
  11. Kwas

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    I sincerely doubt my Phantom is no less "Stable" as you call it, than any other one out there. I'm not saying it drifts all the time, but at times she will. And that is normal. Many on this forum will tell you the same. Drifting as you claim are attributed to natural and physical variables. Wind/breeze, loss/weak GPS/GPS variances which allow for 6-8' drift while airborne, incomplete setup, incomplete/defective compass calibration or, defective components. For example, when using a handheld GPS you will very rarely achieve an exact return to a waypoint. You'll be within 3-4' of it. Why? Because you're using the civilian GPS.

    As I said, the problem that I a having is something new. You keep mentioning the parameters, such as 6 to 8 foot drift, yes, I am well aware of that and DJI also mentions it, but I have NEVER experienced the parameter extremes that you talk about. What I am saying is that I have a problem now that it makes it difficult to fly it now that I never had before.

    Magnetic declination varies and changes. Using the URL I provided before, find yours. Then when doing the compass calibration point your Phantom at that point. Then do a counter-clockwise rotation for both settings. Many times when your craft drifts or wobbles as if it's in a toilet bowl flush that is the reason. You didn't achieve a good calibration.

    I don't buy the magnetic declination factor at all and doesn't change and is constant for any given location. DJI doesn't address it either. Where you start you compass dance is irrelevant. The way you rotate is also irrelevant and also not addressed by DJI but in a pictoral show a clockwise rotation. http://wiki.dji.com/en/index.php/Naza-M ... alibration

    Allowing the compass too close to a car stereo speaker while getting in or out of the vehicle can cause you problems.

    Deguassing the compass requires a magnet and setup to your NASAM assist software. It's best to first watch how it's done on YouTube before you cause any more damage to the compass. Or find with the NASAM it was fine.

    I am not sure about having to degauss the compass at this time, I think that the MOD number is still within range but I am still researching the issue. I have not been able to find any videos related to degaussing the compass.

    You might have a defective GPS receiver. If you carefully open the Phantom you'll see it on the top cover. It's a delicate ceramic and is easily cracked or broken if it was involved in a hard impact "TOP" style crash. (An inverted top over crash/impact).

    I opened it up today and everything looked intact. I have had a few crashes but nothing severe with no visible damage. I don't think that is a issue at this time.

    Lastly, check your motors. One might be running slower than the others causing you to be unstable. Most reliable hobby shops can check them with a tachometer.
    Best of luck, and hope you figure it out.
    Lonewolf[/quote]

    The motors, I'm not sure. I have always had one that seemed a little tight but it never had any effect on the way it flew.

    Thanks for the comments and help.

    Kwas
     
  12. BobUnplugged

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    Have you checked to make sure that your S1 switch is still in the top position?
     
  13. Lonewolf

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    You're entirely welcome. Unfortunately, you seem to feel uncomfortable and unsure with many of the variables that were offered that could be the cause of your trouble thus far.
    A parting offer...Goto: https://www.youtube.com/watch?v=kCT1rRE_UIg on how to properly degauss your compass that you were unable to find.
    Best of luck.