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P2V HEAVY forced landing on low battery

Discussion in 'Phantom 2 Vision Discussion' started by themosttoys, Apr 1, 2014.

  1. themosttoys

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    I've been playing with my Taco (could be taken many ways) gimbal. It's been very windy lately, so good opportunity to test it. The Taco has been performing well but that's for a different thread.
    This thread is to talk about the different way the P2V handles when heavy.
    My P2V with Taco gimbal, amp and Skew Planar antenna ready to fly (with props) weigh in at a full 1381g. In the past, I've done weight testing and in my opinion, this is at the top of usable weight limit for this platform.
    The battery had just dropped below 30% and I was behind some trees.
    I did a full left stick up to ascend above the trees and fly back toward me.
    The P2v struggled, teetering back and forth like it was climbing stairs (similar to the look of when it falls to fast and perhaps enters VRS) but it was not descending, I was ascending. Good news (I guess) is that the video was stable (the Taco was working).
    I looked down and the battery was at 13% (two seconds ago it was 28%).
    The P2V just cleared the trees when it decided it was time to land.
    I was still FULL left stick up and the P2V was LANDING. I looked at the battery and it showed 25% (back up from 13% just a few seconds ago).
    So 25% full stick up and the P2V landed, well it was heading down fast (faster than RTH autoland) I ran and caught it at about 3 feet from the ground (I hang my antenna below the landing gear, so need to catch.)

    I do believe that if it had not been for the extra weight, the P2V would have been able to continue flying (or at the very least not come down so rapidly). I believe it came down early and fast because of the extra weight.

    The battery has about 45 flights on it and was freshly charged 24 hours ago. Used it last week without the Taco (installed this past weekend) and worked as normal.

    Moral of the story, 30% is the new dead. Thank goodness I was not over water or on a return from a long distance flight.

    For those going heavy (gimbal) be careful.
     
  2. Don the builder

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    Good info especially about dropping when too heavy and could be bad news when flying over a body of water. In my early flying days I flew too aggressive and took risks especially over the ocean, "By the grace of God go I" as I never sent her into the drink however came close a few times, now I always strap on my "Getterback" should it drop into the drink but I have developed much more respect for flying over water.

    Here is a shot from this past Sunday in Long Beach, CA (excuse the poor photo taken from my Blackberry). Note the yellow "Getterback". I hope I never have to test it, lol

    [​IMG]
     
  3. themosttoys

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    nice pic.

    Actually, the stock P2V (as you have it) is very reliable and predictable. With a reasonable amount of warning (about a minute+) before it force lands. In other words, in the past I could hold left stick 100% and the P2V would maintain altitude (essentially overriding the auto landing). You should be good to go. If you add a gimbal, be more careful (at least given my recent experience).
     
  4. SlackerATX

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    At 13% (anything below 15) it will start to auto descend and there is nothing you can do about it, at least in my experience. I have no extra weight on my P2V save for the lens kit. Is this not the expected behavior?
     
  5. themosttoys

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    Yup, I agree except the battery showed 30%, then when I went to climb over the tree it instantly dropped to 13% (but continued to climb). Then about 10 seconds later (after I cleared the trees) the battery showed 25% and the P2V landed (landing with 25% showing on the battery and would no longer take off.) four seconds earlier and it would have landed in the trees (I was 100% throttle the whole time, trying to keep it in the air.)

    While it has always been the case that it will auto land at 15% (but you can force it to maintain altitude with full throttle), it has never instantly dropped like that (at full throttle and 25% battery). On my 3.89km flight (no gimabl) I got back with 18%, flying full throttle and it did not force land. Today it would have landed still a mile away.

    Good news is nothing happened, just a bit of an unexpected situation.
     
  6. ITSAPHANTOM

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    The props look insane in your pic!
     
  7. nhoover

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    Interesting. I am torn between getting the Taco and waiting for the next phantom/other platform.

    With a stock P2V, you can override the second battery warning by cranking up the throttle. It's recommended to drain the battery down to 8% or so every 20th flight - I did that by hovering with some throttle to stop the auto-land. Worked fine the two times I've done it.
     
  8. slicknet

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    I'm responding to ITSAPHANTOM comment about the above photo and the props. If the factory props are that flexible and bend to the degree the photo shows, then there has to be a lot of lift being lost. Any comments on this?
     
  9. jimre

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    Don't think they bend anywhere near that much. Most likely rolling-shutter artifact (aka "Jello") from the cell phone camera.

    Similar jello photos of "real" props: http://www.core77.com/blog/object_cultu ... _17253.asp
     
  10. yawnalot29

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    If it does take a tumble into water, are you expecting any of the electronics to survive? Or this is more of salvage whatever you can and replace all the electronics? I imagine the motor will survive provided a good washing.
     
  11. RCRookie

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    Ive read of one instance where the Phantom (not Vision) went down in fresh water and did survive...I wouldn't bet on the camera survival tho.

    Assuming you can get the Vision out of the lake....remove the battery, separate the shell and place in about 5 lbs of rice in a garbage bag for 24 hours....reassemble and test....hope for the best.

    I doubt every case will be the same. But I have read that it indeed can survive. Mileage may vary.
     
  12. Geoelectro

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    Mine did. (vision) It was in the lake for 30 minutes or so. The camera was lost and the battery was damaged. I tool it apart, rinsed it under the faucet and dried it for 1 1/2 hours with a hair dryer. Let it sit opened under a fan all night. The next day It was calibrated etc. and flew. Ordered a new camera and battery. All working. It's been two weeks now since the accident.

    Geo - not flying over water for awhile!