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at sea on this research yacht - worried about signal loss, other issues

Discussion in 'Electronics' started by Bryan Harvey, Jun 2, 2014.

  1. Bryan Harvey

    Bryan Harvey Member

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    [​IMG]

    I have an upcoming shoot on this vessel, 3 weeks at sea. Please take a look at that radio stack on board, and tell me what issues I should be aware of in terms of potential interference, what precautions should I take, what shall I make the bridge turn off during flight ops (radar ? etc), and am I crazy to fly my $30k bird daily over the water. I'm on DJI A2 flight control. I believe salt water itself can also effect radio signal? Shall I limit my range? Limit proximity to the sea surface? Any thought, expertise in this area from you guys is much appreciated. Obviously home base is a moving target, so attitude mode only.


    Getting a bit nervous...
     
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  2. Bo Tornvig

    Bo Tornvig Member

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    Hi Bryan,

    I did a job in the Indian ocean some month ago. Super scary...! Some pro radio freaks told my that the radar is only dangerous if the kopter is very close like 10-15 m. The radar beam will pass the kopter so fast, that it's not possible for it to go in to signal lost and try to auto land several sea miles away... I did all my flights in 4-5 minutes to make sure that I had juice enough and on 2 battery's.
    Have a look:
    http://botornvig.com/ship/

    Cheers
    Bo
     
  3. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Bryan: I would be concerned that compass calibration would be way off if you are on board a metal boat.
    I don't know the A2 system, but is there a way you could test fly without the compass enabled (or its effect dialed way back) while you're still on land.

    Bo is correct: Get close to any high powered transmitter and frequencies don't matter -- the high power transmitter can swamp the 2.4Ghz link you're using to control the copter.

    Have you considered a "floatation kit" made out of pool noodles on each boom of the copter. After a bit of searching on the Internet a year or so ago, I found some pool noodles, both red and blue, that had a 3/4" hole running down the long axis, so it was easy to slice them open and then use cable ties to attached the noodles to the booms. The choice of colors also added to the ability to see the orientation of the copter. The floatation kit will not save your camera or the avionics -- the salt water is likely going to trash those if you dump the copter in the sea, but you might at least be able to recover the carbon fiber.

    I would also take backups of everything that you can -- marine air is pretty corrosive, so electrical contact and ribbon cables are things that you might want to seal with hot glue or something equivalent. By the way, if you ever need to remove hot glue, put isopropyl alcohol on a Q-Tip and dab it around the edges of the hot glue -- it seeps underneath and you can pop the hot glue off with a fingernail (well, most of the time!)

    Hope this helps.
    Andy
     
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  4. Bo Tornvig

    Bo Tornvig Member

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    I mounted a self-inflating rescue wreath on the battery tray.
     

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  5. Steve Maller

    Steve Maller UAV Grief Counselor

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    Bo, I assume you've calculated the buoyancy of that device and it's sufficient to float your Cinestar? I've seen a few such things that were only rated to a few KGs, which didn't strike me as enough to keep the copter from sinking pretty quickly if it hit the water.

    Do you have a part number/link for the one you're using? Thanks.

    And amazing video, by the way. I was in a full pucker just watching it! :eek:
     
  6. Bo Tornvig

    Bo Tornvig Member

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    Thanks Steve :)
    I don't have a link - I found it on sale in a boat shop and it says that it can keep 50 kg floating. That should do the job.
    That said - I don't hope I ever make use of it...

    Cheers
     
  7. Steve Maller

    Steve Maller UAV Grief Counselor

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    Amen to that!
    And let's see...if I skip dessert, I guess two of them might keep me afloat, too! :rolleyes:
     
  8. Chris Fox

    Chris Fox Active Member

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    I have flown in a couple very metal dense areas, and have found that the compass can be way off when on the ground, to the point that the system wouldn't start. In this case I disabled GPS, and took off manually. and once about 5m or so above the structures was able to engage PH functions again without any issue. Your mileage may vary ;) (why do I use the term milage when I know about kilometres??) This was using a Super X flight controller and with a NAZA, not the MK. I still need to encounter that problem whilst using the MK.

    Cheers

    Chris
     
  9. Bryan Harvey

    Bryan Harvey Member

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    Bo, did you do anything special to your flight controller for these flights? Disable any functions? It looks like your are using mikrokopter, while I will be using A2. I too am concerned about the compass and magnetic effect of the metal ship. I'm not sure full manual mode is an option for me. Too Scary!
     
  10. Miron Bogacki

    Miron Bogacki Member

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    Anyone knows how to take off from the boat with mikrokopter system ? Any hint ? The gyro can not be calibrated on moving boat... so... How can I solve that ?
     
  11. Howard Dapp

    Howard Dapp Active Member

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    Bo that footage is incredible! Which camera was used?
     
  12. Dave King

    Dave King Well-Known Member

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    Very nice footage Bo.
     
  13. Bo Tornvig

    Bo Tornvig Member

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    Thanks your kind words :)

    I did not disable anything on the FC. If the Kopter refused to start I just moved to another spot - no problem on a big carrier.
    I shoot it all with the little Sony 730. The only problem was to get all the gear 10 m up, over the side of the ship from the little pilot boat in the middle of the night, in ocean waves...
     
  14. Don LeRoi

    Don LeRoi New Member

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    Bryan,

    This thread is over a month old, so you may have already finished your shoot.

    Is that the Al...ia? If so, great gig. I flew a couple of MKs off her last year. I landed one in the ocean, but it was my error, nothing to do with the ship. Fortunately, it floated and I was able repair it on board and resume flying.

    I have no experience with DJI, but with the MKs, I calibrated the compass on land because of the magnetic influence of the ship. Other than that, the only challenge was calibrating the gyros, which I describe here:

    http://forum.freeflysystems.com/index.php?threads/taking-off-from-a-boat.4946/#post-50025

    -Don
     

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