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Touching Throttle while RTH

Discussion in 'Pro/Adv Discussion' started by t2adze, Apr 10, 2016.

  1. t2adze

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    Hey All

    Used to read here somewhere, but can't find it through search now. Either it was someone crashed the bird, and people decided that the reason was because he moved a stick while RTH - that's what caused the problem.
    Canyou please tell me what does moving the stick do, during RTH that can cause potential damage?
    I am not talking of course about decreasing the altitude so low that you hit something. It was something else.
     
  2. msinger

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    From the Phantom manual:

    Untitled.png
     
    t2adze likes this.
  3. t2adze

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    I see i need to go over manual again. Been 3 months since last time i read it. Starting to forget things!
    Thank you@!
     
  4. Meta4

    Meta4 Moderator
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    As shown above you can disrupt the climb to RTH altitude if you provide stick input during the ascent.
    But you can safely use the sticks during your RTH flight.
    For example you can speed things along.
    RTH wants to drive slowly (10 metres/sec) and you can stay in RTH but you can kick it along by pushing the right stick forward.
    Experiment a little in an open area to see what else you can do.
     
  5. ferraript

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    maybe you are talking about this topic:
    All good things come to an end. Epic RTH Fail
    in short, this could happen:
    you have failsafe altitude set to 100 m
    you fly at 20 m and lose connection
    Phantom starts ascending to 100 m
    you give input to throttle and this input is transferred to the Phantom (because for 1 second connection is restored)
    Phantom stops ascending (for example it is at 40 m now) and heads back to you
    but there is 60 m tall church in its way and you don't have the connection at the moment
    bang
     
    #5 ferraript, Apr 10, 2016
    Last edited: Apr 10, 2016
  6. NormanNormal

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    Wow that is a terrible and dangerous feature.
     
  7. tcope

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    It's not, it's a good safety feature that was added. RTH starts and the Phantom it heading toward a building, a person or whatever. If DJI did not allow the flyer some further control while in RTH,someone could also hold DJI liable for any damages which includes injury.
     
  8. Oso

    Oso

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    This "feature" to stop ascending has never made much sense to me. In my opinion, once RTH is initiated it should be designed to at least ascend to the preset fail safe altitude. That is the whole purpose of setting a fail safe altitude, right? Anything lower has already been deemed by the user to be unsafe, so why would it be designed to stop ascending at only 20m if you touch the throttle during RTH? This is especially dangerous for a new pilot who could easily touch the sticks during the execution of RTH and accidentally cause it to return too low and crash into an obstacle.

    Once the Phantom is already at that safe RTH altitude, then sure no problem to allow additional control (especially added speed) since it is now at an altitude deemed safe by the user.
    If an experienced user wants it to stop ascending for any reason, they can always just cancel RTH and take full control at any time.

    Maybe it makes more sense to have this be tied to the beginner mode. In beginner mode, during RTH the Phantom would always ascends to the user's preset fail safe altitude unless the user cancels RTH. When beginner mode is off, the Phantom can stop ascending with a stick touch when lower than the fail safe since the more experienced user should theoretically know how to handle a potentially unsafe lower altitude.

    Still, stopping the ascent to a preset safe altitude with a stick touch during RTH is so counter intuitive that I'd bet a large percentage of even experienced users don't realize this is what would happen.
     
    JoBe, alokbhargava and NormanNormal like this.
  9. npalen

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    I'm probably missing something here but wouldn't the RC be out of touch with the AC during a typical RTH?
     
  10. msinger

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    It depends why the Phantom is returning home. Normally, it returns due to a low battery or lost RC connection.
     
  11. alokbhargava

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    Unfortunately fail safe is not designed so fail safe.
     
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  12. Maggot

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    Hi, i recently had two very near misses flying my p3. I lost contact with the aircraft when i flew it behind a cliff. After about 6 seconds i reestablished video only to see my craft scooting 2 feet above the cliffline on rth at full throttle. This happened twice before i figured out that i was overiding rth alltitude via my stick control. Sure gave me some awesome and dramatic footage but came so close to losing my precious. Key is to let go of yhe sticks when you lose contact unless you have a really good reason to do otherwise.
     
  13. DennyBoBenny

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    I didn't know it would stop ascending with stick input...I think that's a confusing and potentially dangerous feature. As Oso said, it should always ascend to the preset altitude no matter what, unless RTH is cancelled by the pilot. Occasionally I like to initiate RTH when I'm ready to bring it home, and after it's on its way back, I like to give it some yaw and pan around while it dutifully flies back to the home point. I've gotten some great footage while not having to worry about flying, and just concentrating on the shot.
     
  14. BigAl07

    BigAl07 Moderator
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    Just to pose a question . . . what if (for instance in the bridge situation yesterday) the RTH is going to cause an impact with something overhead (bridge, wires, etc). You'd want to be able to stop the climb easily yes?

    I think it's a feature that needs to be talked about and understood more than removed. Of course I can see many times where the aircraft disconnects, the operator is scrambling (aka panicking) and trying to move both control sticks and if the aircraft has Tx/Rx connectivity it will stop ascending and return home at this new altitude.

    Either way it's something we need to be VERY aware of and practice with it so when/if (WHEN) it happens we understand and aren't caught off guard.
     
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  15. DennyBoBenny

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    Just push the RTH button to cancel it and it will hover...I always use that before it lands, because the RTH landings are a little too hard for my liking.