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flying below set home point

Discussion in 'Phantom 2 Vision Discussion' started by breweraz, Jun 2, 2014.

  1. breweraz

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    I want to get some pics of a deep ravine that is not accesible from below but has a mesa ridge on the top I can take off from. Can I fly my Phantom vision 2 from a locaiton where I go down into the ravine. Essentially flying below my home point.

    My immediate concerns are as follows:

    I concerned about losing satelites considering the walls of the ravine and line of site. I was able to get a bit into the ravine from below and still had 8 satelites but not fully into the ravine which is a bit tighter.

    What happens if I have to hit fail safe. WIll it rise above the home point of its current location and essentially crash into the wall insead of remember the altitude of the home point. It is about 400 ft down to the bottom.

    If I lost the bird it would be almost impossible to retrieve it due to the terain. May be too risky of a pic to get.

    Tim
     
  2. Coreyk

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    I have successfully flown roughly 100 feet below takeoff point like in your situation near a waterfall. I would be careful with losing satellites. I would use atti mode. Just go slow down and see what happens....any indication of trouble and I would full throttle up and get out. I never tried the RTH function while below the takeoff point because I was concerned about that as well so I cant give you any info on that one. Report back if you do decide to go for it as I would be interested to hear about it.
     
  3. nintendrone64

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    I spoke to a city worker who claims he flew his P2 down the Grand Canyon from ground level to near floor. He says the flight went flawlessly, lost no satalitees and extended the craft to at least 3800 feet below him. It's a little risky, so it's up to you but it sounded like it should be no problem.
     
  4. breweraz

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    Thanks for the reply. Just to get some experience and peace of mind I am going out this wekend to a lesser drop and tightness to see the impacts. I agree it is an atti flight and slow not a sport flying scenario. It is just too cool place for pics with old cars and terrain worth shooting with the right sun light. I am not a pro by any means but still like pushing my limits to one day say ...yeah I can do that and actually mean it. :?

    Tim.
     
  5. Byroman

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    Tim,
    I was flying my Vision from the rim of a large, deep gravel pit earlier this week, and thought of your question. I see that there hasn't been any direct answer to your portion regarding how your phantom will perform when engaging RTH from an elevation below where it set it's home point.
    I was roughly 300' above the floor of the gravel pit, so I cast my Vision out to around 700' horizontal distance and then descended into the pit.
    I stopped at about -100' and toggled RTH. I was quite pleased as it began ascending without ANY horizontal movement. It climbed to +60' (of its original home point) and then started the journey home.
    Hope this helps with your journey into the "negative zone". Best of luck!
     
  6. misipile

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    Great thread, I have had P2V+ for few weeks now, always afraid to go into negative altitude. What does the reading say (FPV), does it display altitude in negative format in that case? I can fly in GPS mode below home point, no need to switch to ATTI as long as I have enough satellite locks, right?
     
  7. Garysam

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    Hello Tim

    I'm curious to you where you might be filming what part of the country, I will be in the monument Valley area this July and plan to be in similar scenarios as you have described. Would enjoy hearing your conclusion and your experiences in these scenarios. Any tips or recommendation you may conclude with.

    Sincerely Gary
     
  8. breweraz

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    As far as where I will be filming. I live in Phoenix AZ, We have a summer place in the mountains around Mongollon rim which is a little over 6ooo ft elevation and some nice areas to beat the Phoenix heat. I had been around 110 to 115 this week during the day.

    I asked the shop tech and he stated the Phantom will only fly to 60 ft above its "current position" not the home position. He also stated that is what he "heard" and some have crashed in to a ledge thinking it would climb. I am not taking that as authoritive at this time. It seems to me home is home and when setting the home position it records the altitude as well. I would like to think it will climb to 60ft ABOVE the home as the current altitude would alwasy be changing positive or negative.

    I have not been in a place where I was willing to try it out but looking as I guess first hand experience will be the best.

    Good question about the FPV numbers. . Where I have gone into some revines I was always line of site and frankly never looked. I will check that out next shot. I have one phantom 2 vision that is my experimental bird. It crashed hard one time and due to repairs and all I call it Frankenstien. It looks and has been brought back to life more than once and it has. Right now she flys fine but the camera and wifi feedback is acting up so no FPV info.

    Thanks

    Tim
     
  9. Bespoke Wind Up

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    Your "shop tech" is clueless.

    If you are below your Home Point when RTH is triggered your Phantom will climb to 60' above the existing home point. 100' below your Home Point? Your phantom will climb 160'.
     
  10. Migmon

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    yeah i flew negative once to test it out, i didnt lose it... went down about 100 feet with full decent speed to see if the engines would shut off. they kept going...

    http://youtu.be/XDqek0qacHo
     
  11. Gizmo3000

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    fwiw, when flying GPS, if for any reason you lose Sats, the Phantom will effectively go into ATTI mode anyhow.

    DJI should make the instructions more clear, as the question of flying below home point is asked again and again.

    But since we're on the subject, it would be nice if DJI offered users the ability to change the setting. 20m/60ft above home point is ok, but I've seen some flights where Phantom's had some close calls while RTH amongst very tall trees.
     
  12. misipile

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    Yes, 20m is too low, I would feel much more comfortable with at least double the height. Sometimes trees are just high enough to make me extra nervous.
     
  13. doug86

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    You do have that option. Fly to whatever altitude you feel is good for safe return, then reset your home point at that altitude. IF the bird goes into RTH, it will fly home 20m ABOVE that altitude.

    Yes, it really works. No, your phantom won't crash when it gets home. No, nothing on your phone screen will change to indicate that there is a new home point altitude recorded. I have done this many times. The tricky part is being patient enough and sure that the new home point has recorded. It can take 30 seconds.