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Phantom 2 descends goes down by it self help?

Discussion in 'Phantom 2 Discussion' started by danglife1, Jul 15, 2014.

  1. danglife1

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    Just got the phantom 2 with fpv and DJI Zenmuse H3-3D Gimbal. Oem stock white controler. Drone fly's perfect. Except every flight or other flight all the sudden it will just go down with no controls. Drone goes down straight no crash or wobble. touches the ground maybe bounces and controls come back and goes back up. Sometimes you get the control back before it hit the ground and you can bring it back up.

    any ideas suggestion? the company the we bought it from say they have never heard of this problem. They said to try the advanced calibration on the computer, which we have never done before assuming the company did it when they set everything up.We do the 360 calibration every time with no error lights. We have flown it about 10 times and really want to take it over water but can't unit the problem is fixed. almost every time or every other time it does it once per flight. Still have to try the advanced calibration. Hoping it will work. Could it be some WiFi signal interference?

    Does anyone have any suggestion? or experienced the same problem?
     
  2. QYV

    QYV

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    Do you know which firmware version you're running?

    When the Phantom is descending and you don't have control, what are the indicator lights doing? Are they green? Red? blinking red? blinking yellow?
     
  3. danglife1

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    Not sure which firmware it is will have check. It should be recent since we just got it 4 weeks ago and the company set it up. Not sure if there are other controls when it descends but up does not work. As far as i remember the indicator lights are green.I never saw anything out of the ordinary.Its def not flashing low battery. You can usually fly it for a while after you get it back up. I will have to pay more attention to the lights next time. I was just reading the post about battery voltage sudden drop someone posted hmm.
     
  4. QYV

    QYV

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    I would definitely go ahead and confirm you're running the latest firmware.

    If the lights were blinking fast red that would be low battery (or some sort of battery fault) but I don't think it wouldn't turn green and take right back off.
    if they were blinking fast yellow that would indicate it's in Failsafe / return to home mode but again I don't think the lights would turn green and take right back off after landing... you'd get green lights when the Phantom got near the RC

    If the lights are staying green, that indicates the Phantom thinks it's operating normally. now... this next part isn't guaranteed, but it's an educated guess.

    it's always possible that the firmware was never updated, and if you're on any version 1.x firmware there are basically no controls in place to help you avoid what's called a Vortex Ring State... basically if you try to descend STRAIGHT down too quickly, you're descending into disturbed air from the propellers and the Phantom loses lift and drops straight down there's almost nothing you can do about it.
    The best way to avoid this is always have lateral movement (fwd/back/left/right) while you're descending.
    In version 2.x and 3.x firmware, DJI put in descent rate limits so that it doesn't matter if you're hovering and hold the throttle straight down, the Phantom (theoretically) doesn't descend fast enough to get into that VRS that I mentioned above. This means your descents are a lot slower, so keep that in mind (battery time). in firmware v3 the limit is 2m/s, so if you're 200 meters in the air that means 100 seconds of pure descent... point being don't run your battery down to the end while you're all the way up in the air.

    before running any Phantom firmware updates, get DJI's RC Assistant software and make sure the firmware on your RC is up to date (it has USB plug on the bottom). run some calibrations using the software.
    THEN go get the Phantom Assistant software and run it with the Phantom connected. from there you can see what firmware it's running and upgrade if desired. protip: whenever you update the Phantom firmware, I would recommend running through a quick RC calibration again (yes, in the Phantom Assistant). It's not necessary to use the RC assistant every time, just right after (if) you upgrade the RC firmware.
    ps - chances are your RC doesn't need updating, the RC firmware is still 1.1 but can't hurt to check

    good luck!
     
  5. danglife1

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    Thanks for your help. I will def check the firmware asap. I will post once i find out.
     
  6. QYV

    QYV

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    cool. I was thinking some more and when the Phantom is descending without control - would you say the Phantom is FALLING out of the sky, or landing itself gently? a VRS would cause it to literally fall out of the sky... if it's a more controlled descent/auto-land then it's not VRS
     
  7. danglife1

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    Yes it more controlled decent goes down rapidly but smooth straight props still spinning. Usually drop on its feet maybe bounces couple time and you regain control and back up. Last time it happened. It was about 20-25 feet in the air right next to me started to descend got about a 1/2 foot from the ground and i got control back and came right back up...
     
  8. QYV

    QYV

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    nothing in life is certain but it sure sounds like you're describing a VRS. even if you can't get to the firmware update, fly around and make sure any time you descend you maintain some lateral movement don't descend straight down from a hover. I suspect it won't drop out of the sky unexpectedly :)
     
  9. danglife1

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    ok thanks. I will do some practice runs and see what happens.
     
  10. danglife1

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    Would love to hear anyone else opinion on the problem. Starting to think it VRS.
     
  11. danglife1

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    checked the firmware. it 3.04. everything is up to date. re calibrated the phantom and the rc. Got 2 batt of flights with no problem so far. Kept an eye on descending speed and lateral movement. We will see what happens...
     
  12. ISP5557

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    Sounds possibly like you are using the GoPro app, or something else is causing RFI? That is exactly what happens when your Phantom is set to land instead of RTH, and you have had some sort of RFI. It happened to me and what yours did mimics it exactly. You can regain control sometimes when the Phantom gets closer to you or you get closer to it, because your transmitter overpowers the 2.4 signal. You can't use the app with the Phantom 2. Make sure to turn your phone off as well while you are flying. If I am incorrect please someone let me know.
     
  13. bschaub

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    I have been flying a P2 for 6 months and just found out that holding the throttle in a full down position for a period of time will turn off the motors. I actually had a 'fall out of the sky' at about 4 feet with little consequence but could not figure out what happened. I always thought that only the de-arm procedure turned off props. (I have completely updated firmware.)

    This might be well known to many but new to me as of a couple of days ago when I landed and the motors turned off prior to pulling sticks to the de-arm position. See if your P2 does the same.
     
  14. Mike

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    Sounds like you're initiating auto-land. Check and make sure intelligent mode is turned off in the assistant software. If it's on and you hold the throttle down below 10% for a few seconds it will initiate the auto-land feature.
     
  15. pilsburypie

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    I to am aware from reading that the way to shut down the props on landing is to hold the throttle fully down....... but surely this isn't when descending is it? seems bonkers if it is. If you were way up high you'd have to come down in 3 second bursts?
     
  16. FedeVision

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    i just added a 3 axis gimbal to my P2, was using a 2 axis one, so added a lot of weight too, got two falls on test flights,
    the phantom was no able to maintain hover, always coming down and entering VRS, I solved it increasing Vertical Gain from 120 to 220,
    maybe this could help you too, try 20-30 points increase at a time, until it hovers fine. I also did IMU, Compass, RC and Assistant calibration.
    Hope this help.
     
  17. QYV

    QYV

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    I can't prove it with a citation but I know I've held the throttle full down plenty of times during flight and it hasn't just turned off the motors. I thought that was only supposed to happen when the Phantom detected it was no longer descending i.e. it has touched down. THEN full throttle down will turn off the props.

    I need to look into this intelligent mode / auto land as I've never heard of it or had it happen to me before... is that new in 3.04 or only in Naza mode or something?

    anyway pilsbury to answer your last question just don't hold the throttle FULL down. you can continually descend, just don't hold the stick all the way down
     
  18. danglife1

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    That makes sense. Do you know where in assistant software that would be located. I haven't seen it will have to check.
     
  19. danglife1

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    Re calibrated everything rc and phantom got 4 good flight without a problem. Its did go down once but i think my friend was just descending to fast and he never lost control went right back up. Watching your descend speed and keeping movement while descending I think maybe helping too.
     
  20. danglife1

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    We never had the wifi on the gopro, we knew about that issue. All I can think of is some other signal interference. Someone else said make sure to turn your phones off when flying.