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  1. Juno

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    So yesterday I tried ActiveTrack for the first time with my P4, and noticed that while it did a good job of following me it gradually lost altitude as it did so. Around the same time I noticed that when stopping from forward flight, the Phantom would dip down a bit before returning to it's original height (slightly concerning but nothing too serious).

    Today I saw there was a new firmware update so I installed it, did a cold IMU cal, etc, and took it for a spin. Everything seemed fine at first, but as I was on my second battery and flying relatively low, I began to notice again that it would suddenly drop attitude when stopping from flying forwards, and gain altitude when stopping from flying in reverse. (Sideways flight seemed for the most part unaffected.) What's more is, as I continued to fly, the effect became more and more pronounced whereby it began to lose altitude DURING forward flight as well as gain altitude during reverse flight (fairly quickly too) without me ever touching the left stick. The degree to which it drops/ascends seems to be proportional to the the Phantom's speed.

    As an example of what I was experiencing this evening (all of this without ever touching the left stick): If I fly in reverse starting at an altitude of 10' I may end 30' up after flying backwards 40'. As soon as I let go of the right stick, the Phantom will begin to drop (sometimes for several meters, with a risk of crashing into the ground unless I apply the throttle) before regaining a stable hover at whatever altitude it happens to be at.

    What the heck is going on here? Anybody else experience this? It flew fine when I first got it less then a week ago.

    Edit: forgot to add that the DJI GO App does not seem to show these changes in altitude I've described.
     
  2. sar104

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    The loss of height on stopping has been widely reported. The opposite effect when going in reverse has not, as far as I'm aware. Maybe that is due to fewer reverse flights, or maybe that is due to a compensation effect with the new firmware. I guess I'll see if I get a similar result.
     
  3. SolarDude

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    I saw the same thing today with the height dropping after stopping from moving forward. It dropped quite a bit it seemed but then it didn't happen again. After that I was asked to apply a new firmware update and that update seems to have fixed all the video and range issues and it may have solved the height dropping when stopping from forward flight. I'll have to test that tomorrow and let ya know.
     
  4. Chopstix Kid

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    I suspect that the loss in altitude when coming to a hover is from the loss of ETL and the Phantom takes a moment to compensate for it.
     
  5. John Locke

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    My P4 has yoyo'd 6 to 8' upon stopping since I got it. I sent it in for 3 problems, they gave me a whole new drone (when they said they replaced the main board), and the new one does the same identical 6-8' yoyo thing. Some in this forum have said the new firmware fixed the yoyo, but it didn't work for me. I flew today, it was just as pronounced as before. I deem it "standard operating procedure" for the Phantom 4. I hope DJI figures it out someday. I can't use it for serious shoots, I always use my P3P for that, because I can rely on it.
     
  6. Ramphex

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    Mine drops the altitude a lot at the initial take off, after a couple of mins of hovering of flying it stops that behavior.
     
  7. Chopstix Kid

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    When moving around slowly, mine does not do it. But if I am at full throttle and release it to come to a halt it does drop. Not 6 to 8 feet though. That's crazy excessive
     
  8. stefan350

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    Guess I better hold on to my P3P.


    Sent from my iPhone using PhantomPilots mobile app
     
  9. scatmanr1

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    I just reported the same thing to DJI today and they are aware of th X axis having problems as they call it. Try this, from a few feet off the ground shoot it straight up to about 110 ft and let go of the left stick. Mine continues to go up and then stops and then either goes up again or sometimes down. It does level out eventually so I would not call it yo yo but what the hell! Now bring it back down to about 3-4 ft off ground and vision sensor will show correct altitude but the actual hight will either be way high like 12 ft or in the negative -4 ft. And just like you said, the playback on the remote does not show it


    Sent from my iPhone using PhantomPilots mobile app
     
  10. John Locke

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    I still think they have serious barometer problem in P4, just a hunch. This was never an issue with P3P.

    At sunset today I did some testing, installing some tape over 70% of each of the 4 vents on the bottom of the motor arms. It didn't make any difference. The craft would still drop 6-8' when stopping occasionally. Tomorrow I may try covering the vents 100%.

    My theory was the prop thrust rushing by the motor arms would sometimes create a vacuum vortex at the vents on the bottom, only when stationary in a hover, which plays havoc with the barometer readings. The craft goes up and down to make up for the different pressures. That's why the altimeter doesn't always register the altitude changes in the screen, it thinks it's steady at one altitude, when it's really not.
     
    #10 John Locke, Jun 5, 2016
    Last edited: Jun 5, 2016
    Chopstix Kid and scatmanr1 like this.
  11. scatmanr1

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    Will see, they said yet again there will be another update this week. They pushed the last one out quick because of the LOS on the app


    Sent from my iPad using PhantomPilots mobile app
     
  12. franstob

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    I thought it was only me who have this issue. Please be advised due to this issue. Because today I went to the shop and ask about it, it seems they dont really understand why does it happen. Should I update my firmware? Thanks


    Sent from my iPhone using PhantomPilots mobile app
     
  13. skippype

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    I'm having that exact same problem. I just have to keep pushing the altitude up as I fly forward.