Flying off a large ship

Discussion in 'Cinestar 8' started by Steven Flynn, Apr 13, 2015.

  1. Steven Flynn

    Steven Flynn Member

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    HEy everyone. I have a gig coming up and it's a first for me. I'll be flying off a large research ship. And I'm wondering if anyone has experience flying off a large piece of floating steel? Compass issues? Just thought I'd ask ahead so I can prep. Thanks for anything you might offer up. Steve
     
  2. Jason Smoker

    Jason Smoker Active Member

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    What fc do u have dji / mk? I have never done it but this info helps the masses
     
  3. Steven Flynn

    Steven Flynn Member

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    Yes, I'm sorry, I should've put that in here. I'm flying MK FC 2.5, Graupner MC-13 and MOVI MR.
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Steven: There are a few threads where others have asked similar questions.
    For example:
    http://forum.freeflysystems.com/ind...off-landing-on-a-moving-ship.6153/#post-57945
    http://forum.freeflysystems.com/index.php?threads/dji-a2-and-cruise-ship-out-at-sea.6359/#post-59325

    Summary:
    1. Yes, the ship will affect the compass -- you might be able to recalibrate for that (ships have onboard compasses and they are calibrated to account for the mass of the ship) -- but remember you'll have calibrated *for* the ship -- and the moment you get airborne the ship's effect diminishes.

    2. Yes, the ship's radar and other transmitters, up close, might "swamp" your transmitter as far as the copter is concerned.

    3. The relative wind (caused by the ship's motion) will create "interesting" winds in which to fly as the relative wind and actual wind combine and swirl around the superstructure.

    4. Forget about "return to home" as home will be moving -- and if the copter tries to return to home you'll see it landing somewhere out in the ship's wake.... :(

    5. If you've got a MōVI MR, I presume you've experimented with Boat Mode?

    6. If you have an assistant you might want to practice "reach up and grab" retrieves otherwise you'll experience "landing on pitching and rolling surface" depending on the wind and sea-state.

    7. Others have uses pool noodles (the type with the hole down the center), sliced them to copter boom length, and then sliced them longitudinally, to form floatation devices on each boom. If the copter goes into the ocean, at least you'll be able to salvage the carbon fiber. The avionics, ESC, motors, and electrical connectors are not happy with electrically conductive salt water.

    Hope this helps.
    Andy.
     
  5. Steven Flynn

    Steven Flynn Member

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    Thanks for that Andy. Good thoughts. One question I have is I saw that MK has a firmware v 2.08 update that has boat mode in it. Does anyone have any experience with it? I hate upgrading my firmware unless I really have to... if it works don't fix it ya know. So I've downloaded that firmware and thought I'd have it as a backup, but I'm just wondering if the ship isn't moving fast, and the sea state is calm(ish), would an MK flight control initialise?
     
  6. Steven Flynn

    Steven Flynn Member

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    Oh yeah, also I was thinking of doing the compass before we board as we won't be too far from where we'll be flying (10 miles or so), and then just leave it alone, assuming that once airborne the rig would default back to that compass setting. ? thoughts.?
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    If you do the compass re-cal before you board, you won't be able to rely on the compass for takeoffs and landing (it's really more used for yaw stabilization as I understand it), so that shouldn't be a big deal.

    I suspect the best thing to do may be to use MK Tool and just turn off the compass effect. But others may have better ideas. :)

    As to the firmware upgrade, tough call. I know what you mean about "If it ain't baroque, don't fix it!" :)

    You might want to post on MK's forum and ask advice there regarding the boat mode. Certainly I'd want to test that new version of firmware for several flights before I headed out on the water...

    Andy.
     
  8. Steven Flynn

    Steven Flynn Member

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    Andy. Can you explain exactly what the compass effect setting turns off?
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I think it just alters the degree to which the compass heading is used for yaw stabilization.

    Andy.
     
  10. Jason Smoker

    Jason Smoker Active Member

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    I would turn the compass effect to 0 just be safe. I have mine off all the time! ;)
     
  11. Holger Göhr

    Holger Göhr New Member

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    With MK you calibrate every time before motor start.
    That was a problem on a boat as it moves around and the acc couldn't calibrate.
    With boat mode it goes back and remembers the last values used before boat mode was activated ( dry land) and eliminates that problem.
    That's how I understand it.
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Holger:
    I think you may be talking about gyro calibration on the MK -- which you do every time before motor start.
    Calibrating the ACC is something that you normally do once, with the Flight Controller absolutely level -- and not something that you would do while you are on a boat.

    Just didn't want other readers of this thread doing repetitive recalibration of the ACC -- if the flight controller is not level it causes the copter to want to fly sideways -- as I discovered the "hard way." :)

    Andy.
     
  13. Holger Göhr

    Holger Göhr New Member

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    Yep you are right, typo on my side, of course it's the gyros!
     
  14. Steven Flynn

    Steven Flynn Member

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    Well I went on the ship and it all worked out. Thanks for all your ideas.
    I wanted to pose a question about why would my connector nearly melt away. (yep it was over the ocean, so I got really lucky) This was the second time this has gotten hot... first time it's ever actually melted. The weird thing is that I fly a Heavy Lift with a Movi M10, and the only times it's gotten hot at this critical connector is when I was flying 2 batteries with a modestly light load. In this case we were only flying a GH4. I'm assuming this melt was caused by a bad solder joint... but I'm wondering is there any strange reason that flying two batteries vs. one would change the way the current would draw through this? (I can't imagine why that would be) I remember putting the copter into a very quick acceleration while over the water, and maybe I just over drew the current on it, but it shouldn't have been that bad with a GH4? And finally, on the connector, I need to ask someone how the heck do you solder these EC3 connectors well? I'm pretty good with a soldering iron, but I find them hard to do and not wreck the smoothness of the outside ... thereby preventing them from snapping in.
    melted.jpg
     
  15. Gary Haynes

    Gary Haynes Administrator
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    Try this video.

     
  16. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    And remember, when you push the tinned wire into the solder cup of the connector, keep the soldering iron on the connector until the solder re-melts. When you first push the wire in, it "shock cools" the solder -- you need to reheat it to reflow it to avoid a "dry joint" (which has a high resistance).

    If you are having solder overflow the cup on the connector, you're putting too much solder in the cup at the outset. You can always add more solder once the wire is pushed into the cup.

    Hope this helps.
    Andy.
     
  17. Ozkan Erden

    Ozkan Erden Distributor

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    Steven,

    Do you have GPX file for that specific flight? I'd like to see the power consumption of your craft.
     
  18. Steven Flynn

    Steven Flynn Member

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    thanks everyone for your notes. I'll give it a go today. and here is the gpx file. I don't see anything odd or way out of bounds... but there are certainly better eyes out there then mine.
     

    Attached Files:

  19. Steve Maller

    Steve Maller UAV Grief Counselor

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    I took a quick look at your GPX file, and I see a number of potential problems.
    1. you're flying in a urban area and your compass values reflect what is probably a lot of nearby magnetic interference from buildings and other things. be very careful there.
    2. your currents are all over the place, indicating to me your copter may be seriously out of balance, or a motor or two may not be vertical (see below)
    3. your power consumption topped 3,000 watts, which is very high, and might indicate why your connector melted
    4. one of your BLs indicated 26.0A max current, which is perilously close to shutdown levels. that could spell doom for you.
    5. what is the configuration of your copter? motors and all up weight?
    Motor1: 0.0 14.8 22.0 A Temp: 36 44 49 °C
    Motor2: 0.0 11.6 19.7 A Temp: 33 41 50 °C
    Motor3: 0.0 4.0 13.1 A Temp: 30 34 39 °C
    Motor4: 0.0 5.3 19.3 A Temp: 25 33 40 °C
    Motor5: 0.0 5.5 20.0 A Temp: 30 34 38 °C
    Motor6: 0.0 7.2 20.0 A Temp: 32 37 44 °C
    Motor7: 0.0 17.7 26.0 A Temp: 36 42 50 °C
    Motor8: 0.0 16.1 23.0 A Temp: 35 48 54 °C
     
  20. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Our resident UAV Grief Counselor nailed it.
    Motor 7 is way out of line. It could be a bad motor or a bad sensor on the ESC for #7.

    After you have confirmed the balance of the copter and the vertical alignment of the motors, if #7 still runs with higher current. You could try swapping motor 7 to, say, 5, and see if the high current load moves with it. If it does, then it's the motor. If it does not, then it's the ESC.

    Motor #8 is the next candidate for swapping with, say, #6. #8 is also sucking a lot of current and running hotter.

    Andy.
     
    Steve Maller likes this.

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