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  1. Wetpug

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    Hey Guys,

    This is my first post here. I have the Phantom 4 and have flown it about 20 times and everything has been perfect. It flies like a dream (this is my first phantom) i have been getting very good at flying and gaining my confidence even flying indoors. So my problem was that sometimes when i start up the P4 i get a IMU error for a quick second than flashes to Yellow no gps then maybe back to green safe to fly. This was happening every time i start up. Since i wasn't sure if that was normal and i have been reading about people doing the IMU calibration i thought i would give that a try. So i did the Imu calibration today with a cold P4 and the calibration finished successfully. I went outside and started up the P4 and for the first time i got the yellow warning that the P4 was warming up (only took a few seconds and that went away) then from what i can remember i had gps signal (i have been flying in the same spot for the last week with no problem) i took off and everything seemed normal. After about 3 minutes into the flight the P4 became super unstable and had a mind of its own. I noticed on the video feed that recorded on my iphone (not SD card) that at the point when it became unstable the video went to black and then came back but didn't play correctly. At this point the P4 was hard to control. I would be pushing down full on the motors and it would want to go up. It wouldn't maintain a hover, it was all over the place. This was the first time in flying since i got it that i was thinking i was gonna crash it. I had to almost jump up and do a hand catch to get it out of the air as every time i was pulling down on the motors it wanted to take off.

    After the flight i looked at the flight recorded on the iphone and i noticed that this is the first time that the location tab says "no gps". I decided to give it another test later in the day so i did a compass calibration to see if that would help and the second flight was much better. I can't say that its 100% back to how it was flying before but at least this time it held a hover and was a lot more stable. There seems to be more drift. Before when i would go full speed forward in P mode and i would let go of the forward stick it would come to a pretty quick stop. Now it drifts forward a lot. Like its got no brakes.

    Any ideas of what i should do? Also, in the future if this happens again is there a mode i can switch it to that will let me have control of it rather than fight with it like i did today? I have flown it indoors once and im pretty sure there was no GPS due to the build walls and it was totally fine. It had a little more play in it than when i was outside but it wasn't acting all crazy like it did today. So i can't blame it 100% on the fact i might have not had any GPS. It had a feeling like when i was younger and flying a remote controlled airplane and someone got on your radio channel and was controlling you airplane and you had to fight with that person for control.

    Is there a way to reset the IMU to factory? I should mention that i am on the latest firmware and everything is updated and current, full battery etc.


    Thanks
    James
     
  2. msinger

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    Did you check out the flight log? Try uploading it here to see if it shows anything notable.

    No, but you could try doing another IMU calibration on a level surface.
     
  3. Wetpug

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    I forgot to mention i did the first IMU calibration on a level surface. But i can try again.
     
  4. Wetpug

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    I just upload my flight record to healthy drone.com and here is the results. HealthyDrones.com - Innovative flight data analysis that matters


    I am not sure what to look for. Only thing i see is that i only had 4 satellites when i took off. But i only started having problems with the P4 after about 6 minutes of flight time. At that point i had 14 or 15 satellites. So i am not sure what went wrong. Something must have made it want to fly on its own. It wasn't the wind. It was like it was getting its control from something else.
     
  5. msinger

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    Healthy Drones doesn't show much data. You'll see more if you upload your TXT log here.
     
  6. Wetpug

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  7. msinger

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    Other than the odd looking flight path, your log doesn't indicate anything unusual was occurring. Is it possible that there was some kind of interference in the area?
     
  8. Wetpug

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    No, it's a small village area in southern India. Shouldn't be any major interference. No airports or really anything around here other than small houses. Has it been reported before that the P4 will fly unstable on its own? I mean i was pushing down on the left stick and it wanted to go up. There was no idle. If it happens again would switching to P or A mode help?
     
  9. msinger

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    Not that I've seen.

    If your Phantom ever starts flying uncontrollably, switching to A-mode is the first thing you should try.
     
  10. johnbowen

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    He took off before having 8 or more gps. Once AC is moving, it becomes difficult to update, connect to other gps sats if it took off without a full gps lock.
     
  11. Stealthmatt

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    How did you cool the phantom down really needs to only be less than 20c like 15-18c And was the surface you calibrated the phantom on dead flat?

    I would do a new imu calibration, followed by a compass calibration before your next flight after the imu calibration.