High Performance MPX Foil/Self-righting Trimaran-The Test Model

Discussion in 'Multihulls' started by Doug Lord, Dec 28, 2010.

  1. Doug Lord
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    Doug Lord Flight Ready

    MPX Test Model / Fire Arrow

    Here is the Radio Control System laid out. The picture in the upper left is the deck with the white nonskid material removed to make way for the radio box which will go all the way forward(near top of pix).
    The transmitter is a 14 channel spread spectrum helicopter radio. The servos( shown below on the 2nd row at the far left and far right) that will be used are:
    1) mainsheet winch
    2) jibsheet winch
    3) rudder servo
    4) main foil servo(not hooked up while wand system is tested)
    5) traveller
    6) port ama AOI adjustment servo(not installed initially)
    7) stb ama AOI adjustment servo(not installed initially)

    click on pictures twice for largest view---
     

    Attached Files:

  2. oldsailor7
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    oldsailor7 Senior Member

    Doug, how do you waterproof all your electronic gear on the model?
     
  3. Doug Lord
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    Doug Lord Flight Ready

    MPX Test Model / Fire Arrow

    ==============
    Paddy, it all goes into a sealed box. The top of a servo can stick out of the box if it is covered with waterproof grease or otherwise sealed.
     
  4. oldsailor7
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    oldsailor7 Senior Member

    Thanks Doug. Do you find that application of a silicone grease is good enough to prevent water passing down the servo arm shaft or winch spindle.?
     
  5. Doug Lord
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    Doug Lord Flight Ready

    -----------------
    It should be but I wouldn't trust it if you can do it another way. For instance, the sail winch I'm using has a seal around the shaft and I'll still use clear silicone grease. On a rudder servo you can put that inside and use a tube within a tube with silicone grease to seal the pushrod tube.
     
  6. oldsailor7
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    oldsailor7 Senior Member

    Thanks for that Doug, but it must be tricky on sailboats which have been built to the 1ft box rule. :eek: Lol. :D

    I was thinking of building a 1 inch/foot replica of a Buccaneer 24 in 1 1/2 mm ply and epoxy. Using exactly the same structure as the full size boat.
    Do you think that would be too small ?
    Maybe 2"/ft. :)
     
  7. Doug Lord
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    Doug Lord Flight Ready

    ----------------------
    You can get mighty small servos these days including water-resistant/ waterprooof..... I don't think thats too small as long as you use a really deep keel. And at that size the scale SA might result in a knock down in 4kts of wind so you'd probably want one reefable rig and/or a couple rigs for different wind strengths.
     
  8. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    MPX Test Model / Ama foil idea

    Here is a link to an idea I came up with tonight to solve potential problems that could occur with the ama foil if the designed range is not adequate. This might eliminate the need for servo controlled angle of incidence adjustment in that case:
    http://www.boatdesign.net/forums/hy...controlled-flapped-foil-48622.html#post657798

    UPDATE: Tom Speer posted in the above thread. He recommended this book: http://www.amazon.com/Airplane-Performance-Stability-Control-Courtland/dp/047168046X which I have ordered. Airplane-Performance-Stability- Control
     
    Last edited: Oct 20, 2013
  9. basil
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    basil Senior Member

    Why waste our time on photos of radio systems and batteries? I think we have all seen them before.

    Same old story as Sailing Anarchy - just taking pictures for the sake of it.

    Please take videos when you do launch it - I'll be mighty impressed if you can operate 7 channels at the same time.
     
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  10. Doug Lord
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    Doug Lord Flight Ready

    MPX Test Model

    ==============
    Thanks for your comments.
     
  11. hoytedow
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    hoytedow Carbon Based Life Form

    It was new to me.
     
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  12. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    MPX Test Model

    Here are the miniature(2") turnbuckles that will be used on "water stays" to hold the ama to the main hull-unless I can find a lighter system. They will use 120lb SS wire(or non-stretch line) at a 5 degree angle between the ama cross arm and the vertical tubes for the main hull crossarms. Shouldn't ever contact water except in big waves off the foils. And I may come up with a better system in the meantime.
    As is, this system is simple and quick to attach.The cool thing about these turnbuckles is that they don't, necessarily, have to be adjusted for tension everytime because they can be unhooked under tension and will tighten back up when they are reattached.

    PS- the tube inserts will be coated with a watertight clear teflon grease that will seal the joint as well as make it easier to set up and remove.


    click for bigger view:
     

    Attached Files:

  13. Petros
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    Petros Senior Member

    It seems like using string knots like the one below would be lighter, and less costly. the red colored string is used instead of a turn buckle on the stays for a pocket crusier.
     

    Attached Files:

  14. Doug Lord
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    Doug Lord Flight Ready

    MPX Test Model

    ===============
    Thanks, Petros. That looks to me like it might be a nightmare to adjust if you had to?
     

  15. hoytedow
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    hoytedow Carbon Based Life Form

    Seems to me a taut line hitch would do the trick. No un-tying needed to adjust it. Even small caliber line can be used.

    http://en.wikipedia.org/wiki/Taut-line_hitch

    "Once snug and set, the hitch can be adjusted as needed. To tighten the line with respect to a load attached to the standing part, the user can grasp the standing part with one hand inside of the loop and pull towards the anchor object. The hitch may be grasped with the other hand and as slack develops within the loop, the hitch slid away from the anchor object, taking up the slack and enlarging the loop. To loosen, the hitch may be slid toward the anchor object, making the loop smaller and lengthening the standing part."
     
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