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Fly away? not sure

Discussion in 'General Discussion' started by Pergo1, Sep 6, 2014.

  1. Pergo1

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    I was flying my phantom 2+ last week about 150ft directly overhead when i decided to have it come back all stats were good batteries gps etc. when upon its decent about 100 ft or so i lost control almost looked like the rotors stopped fluttered like a leaf nothing was working. it landed hard i broke its fall with my leg( not the smartest) and it flipped. Not major damage some scraps chipped prop. could have been worse. I changed props and went back up all seemed to be ok. my question is will the rotors stop in mid flight if both sticks are pulled back for some reason?
    Thanks Joe
     
  2. Buckaye

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    Sounds like you might have triggered the motor off sequence both sticks down at 45 degree angles?
     
  3. mmn

    mmn

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    I wonder, if you do that and you are quick enough and do it again, will they spin back up?
     
  4. Meta4

    Meta4 Moderator
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    IF you put the sticks in a CSC position in flight, you would shut down the motors.
    BUT you're going to be doing some pretty crazy moves. It's not something that happens accidentally when you are descending.

    If you did shut down in flight, it would be possible to restart.
    BUT unless you were quite high you would be unlikely to recover before hitting the ground hard.
    A falling Phantom would accelerate toward the earth at approx 10 metres/sec/sec.
    Example of the physics involved ....
    In 3 seconds it would fall 45 metres and be travelling at 30 m/sec and still accelerating downwards.
    Normal descent speed is 2 m/sec. The restarted Phantom would have quite a fight to recover (and while it is trying it is falling even faster). If it could, this would take even more time so you would need plenty of airspace beneath the quad.
    Definitely not something to try from only 100 feet up.
     
  5. darwin-t

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    There is a setting under "Advanced" and "Motor" for "Motor cut off". The choices are "Immediately" and "Intelligent". Check that setting.

    If set to intelligent, going to "no throttle" won't shut the motors down if the quad is descending. At least that is my understanding of it.
     
  6. phantominasia

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    This sounds like a case of VRS, Vortex Ring State. Flying directly down from overhead, smooth flying and then wobbling. I had it happen to me on my 10th flight or so and now am much more careful about descending at an angle.
     
  7. UrAwFuL

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    Sounds like VRS to me as well. Descending straight down at a fast rate is highly frowned upon because the craft is basically choking from it's own wind.

    [youtube]https://www.youtube.com/watch?v=tsd_x1i_vAA[/youtube]
     
  8. ProfessorStein

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    I thought about that, too, UrAwFuL... except... he describes the props as having "stopped". Typically with VRS, the motors rev up and become louder... hard to confuse with stopping. Doesn't seem like this is VRS to me.
     
  9. EMCSQUAR

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    It sounds more like operator pulling CSC. To OP another note you might want to take from this incident is NOT to fly directly above yourself - your Tx works better when Phantom is out in front of you.
     
  10. phantomi

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    I also vote for CSC cause he state both sticks pulled back. :eek:
     
  11. Meta4

    Meta4 Moderator
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    Clearly not CSC in this case.
    CSC does not happen by accident.
    Just imagine what a Phantom would be doing if you were pulling both sticks toward CSC position.
    It would be accelerating to full speed, backwards + sideways while at the same time, spiraling downwards.
    No-one ever does that while they are bringing their Phantom home.
    It just doesn't happen and if it did the pilot wouldn't have to ask if it might have happened by accident.
     
  12. ProfessorStein

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    Ehhh... don't be so sure, Meta.

    You have to remember the Phantom is not instantly responsive. There is a lag in control. You could theoretically push both sticks down and in, from a centered position, quick enough that there wouldn't yet be any apparent change in attitude of the bird. Add to that, the fact that the OP was descending, so the left stick was already down, at least partially, with the right stick possibly being in ANY position as he guided the Phantom back home, and the travel it would've taken to get to CSC in a split second (panic? hand spasm?) could've been very minimal.

    I would say it's completely possible. I am not, however, saying it's terribly likely.

    The biggest problem is I doubt anybody really wants to go out and test the theory with their own Phantom.

    Personally, I'm feeling like it was another battery contact failure. But I couldn't rule out inadvertent CRC simply because of your reasons.