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  1. juniordave nz

    new stuff in the a-class

    The bit you see at the bottom gets glued into the bottom of the hull, and forms the exit point. The large bit glues into this and goes to the top of the hull, you then mount the sliding plates on top. Really all they are is a big wide trunk that can accept the tip on the J board. It is a bit...
  2. juniordave nz

    new stuff in the a-class

    I'm pretty sure ETNZ aren't going to design a set of dragy rudders. I'm sure there is a good reason for how they have shaped them.
  3. juniordave nz

    new stuff in the a-class

    How the hell do you tack the boat with that? Rudder broke just below cassette where bending loads are greatest. Split the rudder in half down the join and crumpled the carbon below the cassette. Whole thing is still intact, just broken. Was lucky to get the boat back to land without breaking...
  4. juniordave nz

    new stuff in the a-class

    Finally got out sailing with them today. Worked really well until one of the rudders blew up going down wind. Have a bit of a repair job to do before the worlds.
  5. juniordave nz

    new stuff in the a-class

    That is a solid carbon section glued up inside both the foil and wing. I wasn't totally happy with it though, so have also put 800gsm of uni over each side of the joint that I will lightly fair in. Not my ideal solution, but it will have to do for now.
  6. juniordave nz

    new stuff in the a-class

    WINGS!
  7. juniordave nz

    new stuff in the a-class

    Went for my first sail yesterday. Boat feels great. Need to sort my systems out a bit, mainsheet was crap. Boat was balanced on boat tacks up and down wind, with new rudder on 1 side and old on other. Current rake puts the front edge of the rudder pretty much vertical, in my design I have it...
  8. juniordave nz

    new stuff in the a-class

    My main interest was the interaction between the wing and the rudder. So in that regard, not so much. My design is to always have two wings in the water, so if I was to have an angle greater than 90 degrees, then I would not gain any extra lift overall. Another consideration was if the boat...
  9. juniordave nz

    new stuff in the a-class

    Cheers samc99us. I was really on interested in the interaction between the wing and rudder in the simulations, so not too fussed about the upper boundary. The results are relative to each other and may not resemble real world conditions that well. I usually find it helpful to look at...
  10. juniordave nz

    new stuff in the a-class

    I need to finish sorting out the numbers from the CFD runs, but it looks like 90 degrees is the most efficient. The models gave me 4.5GB of data and I only want something like 20 bytes. There are ways I could have set it up to make getting the numbers out easier, but I worked that out after I...
  11. juniordave nz

    new stuff in the a-class

    Looking down at wing Looking up at wing
  12. juniordave nz

    new stuff in the a-class

    Lots of modelling going on. Getting some interesting results. Here are some images of a 5 degree horizontal flow (effectively leeway, although a bit to much as the rudder is producing 600N of side force). The images are of the leeward rudder. The upper boundary loosely models the surface...
  13. juniordave nz

    new stuff in the a-class

    Boats sitting in a container awaiting clearance, so still building foils. Testing flow directions before adjusting angle of foil. This is effectively bow up mode and therefore winglet is lifting, in this case about 10kg of support.
  14. juniordave nz

    new stuff in the a-class

    Good points. I will sail with the rudders without winglets if I have time. Modelling is for the other angle relative to vertical, tip down or tip up. I want to look at the difference in drag and the difference it has with regard to lift.
  15. juniordave nz

    new stuff in the a-class

    ^^ Thanks for the feedback. Hope the Nats are going well for you. Half a rudder done, another half to go. I had to order some more carbon to build the other rudder, so that will have to wait a week or so. Carbon pre cut and ready for laying up, sitting on a coffee table that's taking me ages...
  16. juniordave nz

    new stuff in the a-class

    I would think that would be judged illegal, as you are not inserting the foil (in it's entirety) from above. Also a C-L foil would likely go past the 0.75m rule, which dictates how close the tip of the foil can be to the centreline of the platform
  17. juniordave nz

    new stuff in the a-class

    Last photos of a winglet. Going to go finish off the rudder mold's now. Hopefully lay them up over the next day or so. Then hopefully collect my boat on the 31st. Nothing else to do round here at mo, just keeps raining.
  18. juniordave nz

    new stuff in the a-class

    Paradox isn't experiencing any weird helm feedback due to their L rudders. And I don't think you would, it might change the balance ever so slightly when one lifts out. But no real difference to a rudder lifting out under normal conditions. You may get some leeway force from the winglet, but...
  19. juniordave nz

    new stuff in the a-class

    Thanks for your feedback guys. I'm not planning on them being hollow foils. I will fill them up with foam after glueing, the rudder I may do before glueing. The winglet is only an L foil not a T, that's why they are separate. I will build an angle bracket out of uni carbon and CSM core that...
  20. juniordave nz

    new stuff in the a-class

    Much more efficient to put the structure in the shape, rather than use something up the middle. They have a skin thickness of about 1.5mm. They're solid as. I'm going with pretty much the same layup for the rudders, but I will add a bit of internal structure to them as the span is a lot...

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