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  1. Ken Pelletier

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    I've been flying a P3P for a few months now, and just got a P4 and finding that it's not nearly as stable in flight as the P3 is in the same conditions.

    For example, normal take-off / hover without touching the sticks results in very noticeable change in height and position; it doesn't hover in place as the P3 does reasonably well. It drifts higher/lower as well as laterally. This is generally true throughout flight. For example, if I lock a course and fly fwd/back the P4 drifts off course ends up in a very different location on return than on the fly out. The P3, although not 100% precise, flies the same locked course out and back gives me a fairly straight line and returns to the same point.

    This is all while flying the P4 and P3 in the same location at roughly the same time; one, then the other.

    Any thoughts on troubleshooting / remedying this?

    All of the firmware updates have been applied, compass calibrated, strong GPS signal (18 satellites).

    Thanks.
     
  2. msinger

    Approved Vendor

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    Did you try calibrating the IMU on a level surface too?
     
  3. Ken Pelletier

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    Thanks! Yes, I had done an IMU calibration on a level surface before I began flying it, but, sure enough, doing another just now seems to have cleared things up.
     
  4. Kman

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    I have noticed the opposite. P4 is super stable and tracks straight while my P3P wanders a bit.
     
    snowghost likes this.
  5. chris digata

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    same here.. my P4 is static
     
  6. isopro

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    A bad IMU calibration can cause instability and even a crash. Always check sensor values before take off, overtime IMU can also become uncalibrated, and might need new calibration if not in the proper range.
     
    #6 isopro, Mar 25, 2016
    Last edited: Mar 25, 2016
    Sim597 likes this.
  7. Sim597

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    Is or are there some actual values or numbers you could tell me to watch for when looking at that it looks Chinese. I'm not Einstein but I'm not a complete fool, if you could tell me or us it would be much appreciated!

    I can see those numbers and always wish I could make some sense outta them or tell if it looked cranky.
     
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  8. isopro

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    the Gyroscope MOD reading should be near 0, and the Acceleration MOD reading should be right around 1.0, Compass MOD 1400-1600, if they are not really close to those range, it require an IMU calibration.
     
  9. phantomnoobpilot

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    odd. my P4 is much more stable than my P3
     
  10. snowghost

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  11. Jonah

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    Thanks for this great info. Quick question - when I look at this sensor data with the Phantom parked on a flat service with no vibrations the numbers kinda bounce around a bit. Is this normal for the data to fluctuate a bit but to be near the numbers you mention? TIA


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