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How fast to descend?

Discussion in 'Pro/Adv Discussion' started by PhotoGuyAaron, Sep 6, 2015.

  1. PhotoGuyAaron

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    I had trouble getting my p3p to come down with any speed. Is it true if you pull the throttle stick all the way back for 3 seconds or more the motors will cut out?

    I don't want to crash but it is just descending so slow. I try to hold the throttle back as much is possible but I am afraid I am going to kill the motors. What is an acceptable descent rate?

    Any advice would be great:
     
  2. cott33

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    The 3 second rule only shuts the motors off when the Phantom recognizes that it is no longer descending. Mine appears unstable during full speed descent. Just read this morning it's best to descend at an angle because of aero effects.
     
  3. PhotoGuyAaron

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    Thank you very much! I will test the horizontal decent for stabilization.
     
  4. III% Streve

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    +1 100% correct
     
  5. Alex_

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    The reason for descending at an angle is to avoid Vortex Ring State which can happen to any rotor based craft. But the Phantom is limited to descent speeds that avoid this. I was always really worried about it when I first got my P3 (have had it happened on other quads), but now after half a million feet of flight, I descend at full speed all the time and have never had an issue (knocking on wood as I type this!). I typically fly at just under 400ft since I take off from my house and don't want to bug the neighbors, so getting down quick is key.

    Don't fret about holding the left stick down, it will come back safely.
     
  6. Wibble

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    They limited the descent speed considerably because of this. Very annoying older models could come down much faster.
    Even the P3 though still fights and struggles coming straight down - you can hear it but never caused me any problems.
     
  7. matti

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    I guess no FW version has ever shut off the motors even during more than 3sec throttle-down descent, right?

    I guess the motors might theoretically be shut off IF there is an upwards wind causing the drone to keep its vertical (and horizontal?) position in the air for 3 sec (i.e. mimicking it was on the ground). But I guess that is highly unlikely...

    Anyway, now that I'm more aware of the vortex ring state, unexpected GPS & compass interference etc, I'd do the ascent and descent even more carefully than before with the worst-case scenario and a plan to handle that in mind.

    There is a nice (Oct 2014) video about this:

     
    #7 matti, Mar 21, 2016
    Last edited: Mar 21, 2016
    Roamer105 likes this.