Taking off/landing on a moving ship

Discussion in 'Cinestar 8' started by Jack Wrangham, Feb 18, 2015.

  1. Jack Wrangham

    Jack Wrangham Member

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    Hi Everyone

    Anyone ever flown from a moving ship? We have a job based on a cruise ship coming up and we'd like to get some shots whilst sailing. The thing im trying to work out is taking off and landing whilst the ship is moving - I think i'll have to get moving straight away to keep pace, take off should be ok, but landing the system will be at an angle, landing on the flat surface could be difficult! Ship could be doing 20-25mph

    Does anyone have any experience with this? Catching probably isn't an option as we fly an x8 config... could use the s900 but it might not have enough power!

    Cheers!
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Jack:
    Just from an "operator's" (as the FAA wants to call sUAV pilots) point of view, the ship might be doing 20-25mph, and that will create a relative wind across the deck from the bow to stern -- but if the actual wind (that you'd experience if the ship were not moving) might be adding or subtracting from that.

    So if the actual wind is also coming from the direction the ship is sailing, at say, 15 mph, then relative wind + actual wind means you'll be in a 35 to 40 mph wind. On the other hand if the actual wind is blowing from stern to bow, then the wind you'll be experiencing will be 5 to 10 mph. The degree to which the actual wind effect modifies the relative wind ("the actual wind component") varies, as you can see, depending on where the actual wind is coming from.

    I'd certainly consider getting a wind meter so you know what you're dealing with -- otherwise you may find that the copter lacks enough "penetration" to be able to travel through the air fast enough to keep pace with the ship, or from a stern-shot back to the take-off point.

    Obviously you cannot use "Come Home" as "home" is moving!

    The best you could do to practice is either fly in high winds before you go, or use a simulator and crank the wind up -- depending on where you are on the ship there will also be a significant amount of "curl-over" -- turbulence caused by the superstructure as the boat plows through the air.....

    As to the landing, the landing will be aerodynamically no different from landing in a high cross wind -- except, of course, you cannot use position hold as the "holding point" is moving. You are correct that the copter will be canted over because, to land vertically, it has to be flying horizontally at relative wind + actual wind component. One possibility, if you can arrange it, would be to take off and land on a stern deck that would be in the lee of the superstructure and this would cut out the relative wind -- but you would still be exposed to actual wind and have to handle curl-over.

    Andy
     
  3. Jack Wrangham

    Jack Wrangham Member

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    Thanks Andy, yep will definitely be using a wind meter! Should be ok I think, as long as i'm sensible and dont push it!

    Thanks again for the advice.
     
  4. Steve Maller

    Steve Maller UAV Grief Counselor

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    Many videos I've seen and conversations I've had with folks who have done this (*successfully) indicate that the preferred way of landing a multirotor on a boat (moving or not) may be to have somebody grab it out of the air. This is obviously a very dangerous and delicate operation, and should be planned, rehearsed and properly prepared for. The "catcher" needs adequate protection, both from the spinning blades and from losing their footing and falling overboard. As many of us are flying coaxially-configured copters, "catching" a multirotor can be even more difficult. It's one of the good arguments for using retractable landing gear on these machines, as it gives a better, safer surface to grab.

    Good luck!
     
  5. Steve Maller

    Steve Maller UAV Grief Counselor

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    It's a bit off topic but here's a video y'all might enjoy of a training mission with the US Coast Guard. It's not that impressive until you realize how fast the boat is moving and how "stuck" the chopper is over the boat. Now imagine that was your octo instead. :eek:

     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I always thought that choppers built up a huge static charge that had to be grounded but this guy doesn't appear to have done that.
    But as you say, that's quite a scary speed.....

    Andy
     

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