Kurt Hughes paper on wingmast design focusing on wood/epoxy masts

Discussion in 'Multihulls' started by Corley, Jan 16, 2017.

  1. Corley
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    Corley epoxy coated

  2. cavalier mk2
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    cavalier mk2 Senior Member

    Interesting read Corley. It is sort of a no duh thing. Make wing masts like airplane wings for better strength! They put those frames in there for a reason.... While trying to find Gougeon wing mast plans I located the Newick modified version used on his 53' Limmershin design. They should be available at the Mariners Museum if they resolved things with Pat Newick.
     
  3. UpOnStands
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    UpOnStands Senior Member

    Corely; thanks for the page - very interesting
    airplane wings are built around the main spar (mast web) to transfer body loads into the aerofoil surfaces. Quite different loading patterns from masts as the shear loads at the plane body-wing junction are dominant.
    One question. The designers sweat the loads/thickness to cut the weight and then we add internal plastic pipes to carry wires etc. Seems rather a waste of material and weight. Cost is low but...
    Has anyone made internal longitudinal stringers (hollow and integral to the mast structure) large enough to replace the plastic pipes? Clearly this would be for a carbon fiber mast.
    Seems like the large large diameter hollow stringers would add significant column stiffness to the mast.
     
  4. upchurchmr
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    upchurchmr Senior Member

    Cavalier,

    Don't get too carried away with the aircraft design comparison.
    Military aircraft look nothing like this.
    Its a different world.
     
  5. cavalier mk2
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    cavalier mk2 Senior Member

    Easy sports, carried away I'm not.
     
  6. UpOnStands
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    UpOnStands Senior Member

    What weight of cloth would be recommended for the 4 wiring conduits?. Each can take 16mm dia wire as designed for the seatalk wire. Bigger recommended?
    The conduits are made in 1.5 m lengths using a wood former as shown.
    10m Mast is unstayed, 30cm fore-aft, 20cm lateral tapering to 15cm x 10cm at the top.

    Cloth shell is laid up in female form, conduits added with ring frames. Two halves are glued together, then the bulk of the mast is laid up - 1 mm uni then spiral wrapped with carbon tow, repeat to design thickness. Not autoclave perfect finish but I want the carbon on the outside, not the inside
     

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  7. Richard_F
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    Richard_F Junior Member

    That is interesting, do you know if the Newick version is available?
     
  8. Scuff
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    Scuff Senior Member

    You can contact the Mariners museum and ask. I made an inquiry regarding Dick's rudder designs. It took them a while but did provide what I was looking for. At the time I contacted them you couldn't go in person. Bill Barker was my contact.
     
  9. MichaelRoberts
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    MichaelRoberts Archimedes

    Here are some pictures of the 20 m carbon wing mast my wife and I built for our catamaran The structural/aero design took me a few years to refine. It has to take Max 15 tonnes compression.

    Perhaps these might give you some ideas

    Michael
     

    Attached Files:

    revintage likes this.
  10. peterbike
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    peterbike Junior Member

    Michael, would you mind (when you have some time ?) explaining your design & construction process ?
    ie ; I see a timber frame up & foot -- but you say it is a carbon mast...
    beyond that I am lost ? :eek:
    thanks
     
  11. MichaelRoberts
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    MichaelRoberts Archimedes

    Hi Kurt

    1. There are 40 ribs. Designed using Rhono 3D CAD. All cut by CNC, all different sizes.
    2. We bent 1 mm aircraft ply over the ribs and stringer structure.
    3. Then we laminated many layers of uniaxial and uniaxial carbon over the ply.
    4. The wooden framework remains inside and contributes to the short wave buckling strength (aka crinkle buckle)
    5. After the carbon was rolled with epoxy we closed a 20 meter long bag around the whole thing and vacuumed the lot. But not too much vacuum because it would crush the ply. Just long enough to consolidate the fabric.

    Hope this makes sense

    Best of luck
    Michael
     

  12. MichaelRoberts
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    MichaelRoberts Archimedes

    Typo
    Rhino 3D
    And another pic just for fun
     

    Attached Files:

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