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Irratic flight behavior w/Phantom 2

Discussion in 'Phantom 2 Discussion' started by scalvidgal, Jun 28, 2014.

  1. scalvidgal

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    Hi all,

    I am a newbie but I've flown my phantom 2 now several times in the last 4 weeks since I've owned it. I've read all about the flyaways, etc. and that hasn't happened to me, BUT... I am NOT confident in the way my last two flights went... which ended in crash landings & broken props. The two flights have been in the middle of the Colorado rockies. Once was at about 8000ft in a wide open field - no towers/power lines, and the latest one was at about 11,000 feet and again open space with nothing to interfere. No idea how many satellite locks I'm getting (how do you tell that?) but I follow the procedures in the manual and also calibrate the compass before every flight. I would assume I would be getting a lot of signal seeing as I am at such high altitude.

    Basically the drone seems to "drop" a foot or so when trying to hover and also drifts left or right. When I try to land, it comes down really fast, becomes uncontrollable and then wham... hits the ground. I haven't tried to go real high or anything because to be honest, I'm TERRIFIED.

    I have the zenmuse 3D attached as well as a little unit to send a video feed. Here is the kit I bought: http://www.amazon.com/gp/product/B00JRE ... UTF8&psc=1 (I didn't install the Iosd mini -- don't even know what that does?) I just wanted a video feed so I can see what i'm filming. Would the signal from this be interfering??? It flew a lot better before I added this but still it wasn't perfect (however I COULD land it!)

    I also have not calibrated anything because I am on a Mac and don't have access to a PC.

    You will be my hero if you have any info to help!!! Thank you!!
     

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  2. sar104

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    So are you saying that it flies around fine but you can't control descent?

    Firstly - flying at those elevations I would recommend losing the prop guards, which cause stability and lift problems even at low elevation, and I would suspect those to be the problem. Secondly - the inevitable question - although I don't think this is the issue: you do have the GoPro wifi turned off?
     
  3. scalvidgal

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    Hmmmm interesting! So elevation is an issue? Maybe the thin air? Yes... it flies REASONABLY fine... it's definitely wobbly & drifts a bit and yes, I can't really control decent. And yep... gopro wifi turned off. Copy that on the guards!!
     
  4. sar104

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    Yes - the low air density results in less thrust from the props. Try it (carefully) without the guards. Don't forget to switch back to the shorter screws when you remove the prop guards, or you will damage the motors.
     
  5. twodips

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    I've been experiencing the same issues in AZ since the last update. Did a complete calibration which returned my gains to DJI specs and it now has the same issues.
    What's really strange is if descending and I try to bump it a bit left or right to center the landing one motor almost stops like you can't run two sticks at the same time.
     
  6. sar104

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    Calibration doesn't change the gains - that requires manual intervention. If you are running 3.04 the current default gains should be 125, 125, 120, 140, 260, 260 - does that sound right? That's my configuration (actually I'm running 3.05 but it's functionally similar) at 7500 ft, and it flies fine. Prop guards?
     
  7. twodips

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    Yep with the exception of the 260, I cut that back to 200 at the suggestion of another discussion on the gains. I've been running prop guards since day one and up until recently have had no issues until the last update. Flew solid, hovered fine and even in a 10 mph wind did ok at holding position.
    Not so much anymore.

    Today was a bit scary as I was landing I hit RT stick just a hair (while still cutting back on power to land) and it went into a serious wobble. Thankfully I was high enough and had sense enough to release both sticks and let it recover. I did hear a pitch change like a motor or two not spinning as high as the others.
    Once before when it did this I was looking at it and I swear I saw one prop almost stop then recover.

    BTW, it's a newer P2 non vision w/P3-2D gimbal.
     
  8. damoncooper

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    Research VRS here. Sounds like you may be encountering that.
     
  9. twodips

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    Thanks for the info Damon, after reading up on VRS it sounds about right... Learn something new every day!
     
  10. damoncooper

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    In my unscientific and small sample size of posting in these forums, it seems to be a leading cause of downed Phantoms (and major source of revenue for DJI, speaking from my own experience :) )
     
  11. scalvidgal

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    I'm sure I sound like an idiot... what does VRS stand for?? : /
     
  12. damoncooper

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    Vortex Ring State
     
  13. sar104

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    Vortex ring state. It occurs when the aircraft descends into its own prop wash (rotating descending air) and the props lose lift.
     
  14. scalvidgal

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    AWESOME thx! will research :)
     
  15. twodips

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    Well I completed two flights after reading about VRS and keeping that info in mind while landing I had no issues. :D
    Thanks again for the info!
     
  16. damoncooper

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    They should put this info right in the manual IMO.