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uncontrolled descent

Discussion in 'General Discussion' started by snbfamily, Feb 9, 2014.

  1. snbfamily

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    I was hovering at about 50 feet and slowly descending when I lost the signal, Instead of reverting to fly home mode, my drone continued to descend ultimately crashing into a foot of salt water. Plenty of battery left, ug.

    two questions--has anyone had this sort of failure and have a diagnosis ? also, any tips on how to remediate the situation ? The drone starts up but at least one motor appears to need replacement and I can't link to my transmitter even after following the protocols.

    thx for any thoughts
     
  2. F6Rider

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    Ouch, salt water, that's bad. the only thing was to remove the battery at once, dis-assemble the shell and clean and dry everything you can reach, using compressed air. Clear or plain water is actually a bad conductor of current, but as you add impurities (salt) it becomes better and better depending on the PPM of the salt amount. It is quit possible you did some significant damage to the on board electronics. I wish you luck in getting it back in the air.
     
  3. dkatz42

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    Not to mention that salt water is very corrosive. I took a rogue wave over a laptop once (long story) and even though I flushed it out within a few minutes with fresh water, all the copper turned green...
     
  4. Buk

    Buk

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    How did you determine you lost signal?

    Are you sure the motor was damaged in the crash and didn't fail during flight?
     
  5. papayanirvana

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    The exact same thing has happened to me this morning, except it just got a little sand & seafoam:

    About 13 minutes into the flight, early this morning, no wind, I was working my way back to the landing pad.

    I came straight down... a little hot to see how it would handle, then eased up when it seemed to be going down fast. At 50 feet you'll notice a slight shaking. And at about 25 feet, it really began wobbling and basically fell to earth...err sand. (consistent with losing power to a prop)

    After I cleaned it up, and re-armed it, one of the propellers just spun lazily at about 20-30 rpm (compared to 300?). I checked the rotation.. bearings seem fine... the thing is new, this is my 4th flight.

    ..loose connection? I would appreciate any ideas and solutions.
    check the 17 second video of the crash: https://www.youtube.com/watch?v=DtOZWQ7P9jo
     
  6. Seahorse

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    Sound like you both pulled straight down...Vortex Ring State.. :idea: Watching the video would seem to confirm that. Plenty of threads about it, short version reads, make sure you are moving laterally as well as vertically.
     
  7. papayanirvana

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    thanks so much for the fast reply!... makes a lot of sense. You don't have to take aerodynamics into account much to fly these babies, unless I guess you are descending right into your prop wash.

    Incidently, I flipped the GPS toggle a couple of times and the propeller is working fine again.
     
  8. papayanirvana

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    not quite fine... the 1 propeller is still a little wonky... When armed it will magnetically ratchet around for a while and then start working correctly.
     
  9. Seahorse

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    New motor time unless you want to risk it falling out of the sky...[FACE SCREAMING IN FEAR]

    Sent from my HTC One using Tapatalk
     
  10. Justgregg

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    I had the same problem. I know how to perform a descend! The thing did a flat wobble and crashed. It's NOT unbalanced props OR bad motors. I replaced all mine with the new tmotor antingravities! Didn't help. It's a power issue either in the board or the naza.
    On its way to dji service, then to craigs list. From reading all the new posts on this same issue, I bet dji service is swamped!!!
    I hope some one posts on what the REAL problem was!!
    Pretty frustrated with this expensive buggy UAV!!
     
  11. papayanirvana

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    Talking to Atlanta Hobby, they said the wonky rotor was indicative of the motor running on 2 of the 3 phases... I am hypothesizing that I cracked a solder joint to the motors. It flew a couple times after the crash, but the wonky prop comes and goes. Is there a schematic of the phantom 2 somewhere?
     
  12. jimdenburg

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    Like this? [youtube]http://www.youtube.com/watch?v=sw4Ej41niO8[/youtube]