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Flying Lower than Take Off Point

Discussion in 'General Discussion' started by whoss, Aug 23, 2014.

  1. whoss

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    I have some really nice canyons in my area that I'm going to fly from the highest point down into the Canyon. Before I send me way too expensive Phantom below the altitude of my starting point, I need to ask a question.

    Is there anything programmed into the phantom that will cause problems is you fly below your take off altitude. Does the Phantom think it crashed when you fly -100 feet from take off or does it not care?
     
  2. OI Photography

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    Flying below take-off height is fine, won't cause any problems for the Phantom's flight systems. If RTH is triggered at negative height, it will first fly up to starting height + 60ft before starting the path back to home point.
     
  3. whoss

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    Thank you very much. I will fly today.
     
  4. Meta4

    Meta4 Moderator
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    No problem at all with the altitude .... but one big potential problem could be GPS.
    If you are flying into a narrow canyon that restricts your Phantom's clear view of the sky expect to lose GPS satellites and be prepared for that. WIthout GPS your bird will not know where it is or where it took off and how to RTH.
     
  5. ProfessorStein

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    Technically, it'll know where it took off... it just won't know how to get back there. ;-)
     
  6. BlackTracer

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    Worst scenario: you lose gps and control signal. Guess what happens? The craft will land right where it is. Potentially at the bottom of the canyon! Be careful!!
     
  7. whoss

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    Thanks to all for your responses.
     
  8. MadMitch88

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    I think within 5 years most consumer drones will be utilizing multi-path radar and possibly optical recognition to navigate themselves in addition to GPS. GPS is a great technology but does have limitations --- such as flying in a canyon or valleys or in heavily-wooded areas where LOS to numerous satellites might be impossible.

    Avoidance radar will help immensely in preventing crashes and flying into obstacles like trees, buildings, cell towers, etc.

    We are only scratching the surface of what these things can do.
     
  9. Wedeliver

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    I received an award from Flytrex for flying 50' below my starting point. And I got an award for flying over 7000'. I feel like a boy scout trying to get all my badges, and I have amassed a bunch of awards at flytrex.
     
  10. pawnmeister

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    Be very aware of the number of sats locked as you descend into a canyon. As I descended into a canyon satellites locked dropped from 11 to 7. I was only 100 ft below original take off point. I decided to bring her back up at that point...it would have been 1000 feet down if it decided to land itself! All it takes is a momentary loss of control signal, a tree between you and bird can easily cause that, and you may not be able to regain control to bring it back.
     
  11. HarryT

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    Especially if you have a Vision or a Vision+: their 5.8GHz control signal is much more easily blocked than the 2.4GHz control signal of the P1/P2. On a P2 a tree can block your FPV video feed, but it's unlikely to block the control signal.
     
  12. Pierrot78

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    So you all say "yes there'll be no problem flying lower than operator and returning back afterwards".

    And I could imagine being on the top of this dam, piloting my P3 down along the wall, with a safe RTH?

    [​IMG]
     
  13. RoyVa

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    Common sence. Think radio controls and line of sight. These are classed as hobby craft and don't have 5000 dollar flight controls. They are intended to be flown in some field or open area by us kids so to speak watching them fly. We of course take it to the next level and push them to their limits and beyond. Yep I do it myself. Bigger and better antenna's fly father and faster. It's great!
     
  14. Meta4

    Meta4 Moderator
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    Yes ... you can fly off a cliff and descend. No worries with RTH.
    There's nothing weird or tricky about negative altitude.
     
  15. Pierrot78

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    Thx Meta4! :)
    (incidentally, I enjoyed looking at your portfolio; nice pictures, and very interesting to see what foreigners look at when visiting one's own country).