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Descending - too slow.

Discussion in 'Pro/Adv Discussion' started by Cralis, Jan 24, 2016.

  1. Cralis

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    Hi guys,

    I'm on my 4th flight, and having fun. I have an issue with the descents though. If I want to ascend fast, I go full up on my throttle stick, and it goes up and an acceptable rate.

    However, to come down, I am too scared to descend fast, because if I go full down stick, won't the motors cut, as that's how we disarm the motors, right? And disarming at altitude could be pretty interesting.

    So I come down at 3/4 down stick, and it seems to come down pretty slowly. I haven't broken 100ft yet, probably due to my fear of the descent.

    Advice?
     
  2. msinger

    Approved Vendor

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    When the left stick is in the full down position, the motors will only shut off if your Phantom stops moving for 3-5 seconds. A CSC is the only thing that will kill your motors while you're flying.
     
    Cralis likes this.
  3. Garrie

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    This issue has been brought up countless times in this forum. When descending, even at full throttle, the engines will not cut off.

    It will only cut off when the drone is not moving(ie. When it has landed) and the down throttle is held for a few seconds.

    As long as the bird is descending the engines won't cut.
     
  4. Karthikdoc

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    But it's not advisable to come down in full throttle... Because your phantom could get into a vortex spin... Even though the motors will not shutt off until u reach ground and stop moving for 3 to 5 secs...

    This is vortex spin

     
  5. Cralis

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    Yeah thanks, it gets a bit unstable on a direct descent, so I have been avoiding them.
     
  6. Meta4

    Meta4 Moderator
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    If you have a P3 (and don't handicap it with prop guards), you don't have to worry about that.
    It used to be an issue with the P2 before DJI slowed their descent.
    The P3 motors are offset to prevent that.
     
    nhoover likes this.
  7. Cralis

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    Oh really, @Meta4 ? That's pretty cool!
    I'll try it on todays flight. If it becomes a lawn dart, I'll reply appropriately. :)
     
  8. gringorio

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    The other day I was flying up and down some steep canyons near Tucson. At one point I was descending a steep slope and realized the left stick was all the way down and was surprised at the slow rate of descent. There was no "vortex spin" or loss of control. I was happy to see how well the P3P descended compared to my P2, but it sure seemed to take an eternity to descend back to the home point. Either way, in my experience, full down throttle was not a problem. Any one else?
     
  9. Meta4

    Meta4 Moderator
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    The P3 descends 50% faster than the old P2 - 3 m/s instead of a snail's pace 2 m/s and it's due to the offset motors that direct propwash away rather than straight down.
    I've tested it numerous times from quite high up in still air.
    The only possible issue I've heard of was one P3 lumbered with prop guards that may have encountered VRS.
     
  10. happydays

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    This won't happen with a P3. It used to be an issue with P1 and P2 models. The P3 has two things to counteract VRS - the motors are slightly offset to wash the wake out sideways; and descent speed is limited down to 2 m/s. You can absolutely and safely come from any height down holding the throttle fully down. If you're worried about it though, just add in a little side to side action while descending. With P3s keep an eye on the monitor; you won't see a faster descent speed than 2 m/s though. So bear that in mind if you're going up high - to come back down from 120m or 400' will take a full minute.
     
    byrne68 likes this.