A Cat on foils wins NZ Nationals/ Worlds Start Tuesday

Discussion in 'Multihulls' started by Doug Lord, Feb 8, 2014.

  1. Baltic Bandit

    Baltic Bandit Previous Member

    I've never used an ignore list in 39 years of online participation. I don't like that folks can say negative things behind my back. I have not personally attacked anyone in this forum. I've been attacked.

    I will continue to read content to insure I do not continue to be attacked.

    As I said, most of my participation has nothing to do with Doug Lord. And I hope that the standards of personal attack are kept level between all posters. So I respectfully request that Post 25 be edited to conform with the standards I am being held to.
     
  2. Doug Lord
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    Doug Lord Flight Ready

    A Cats on Foils!

    Last racing coming up Saturday and Sunday for this most important Worlds.
    Some speculation has light air in the forcast which would be good-if only to get a clear idea how the foilers do in those conditions.....
     
  3. Baltic Bandit

    Baltic Bandit Previous Member

    Depends on the blades, one of the reasons that foiling is unstable is that they are having to do it with basic C curved blades to fit in through the trunks. but apparently they have a different laminate schedule to make them more flexible thus as they bend they generate more lift component

    One creative member IIRC its Landry the class president - has created a "cassette within a cassette" => and that has been ruled legal. And while he is not sailing with foiling boards, this opens the door for being able to "retract the foils" even for more aggressive "J" shapes by retracting the whole exterior cassette (its basically a box almost the width of the hull

    Now to implement this will require massive surgery on many boats. So there is a fair amount of consternation going on.

    Again if you want to hear the A Class sailors speak on this themselves, head over to Sailing Anarchy
     
  4. Jim Caldwell
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    Jim Caldwell Senior Member

    The cassette system is what I was referring to with the J boards shown.
     
  5. Doug Lord
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    Doug Lord Flight Ready

  6. Baltic Bandit

    Baltic Bandit Previous Member

    Well from the photos essentially you have the hull reinforced enough that essentially you only have the two vertical sections of the hull at that point. And you drop a "box" into that opening that contains the actual cassette guides for the DBs. and then you pin the box in place.

    that way to "fully retract" the foils, you just unpin the box and pull them out.. this gives you essentially the diagonal of the hull as your limit on the curvature.
     
  7. Doug Lord
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    Doug Lord Flight Ready

    A Cat on Foils!

    I've been thinking about the control issue a lot: what is needed is some way to control the rake(angle of incidence) of the main foils. A wand would work if it moved a flap-moving the whole foil is probably not workable. And is probably not legal.
    I'm thinking that, if it were legal, using a twist grip on the extention tiller could allow individual or simultaneous control of the AOI. Not too hard to rig-I did it on my 16' foiler and that part of my system worked very well.
    It would require a trunk within a trunk:
    1) The daggerboard would be locked to the movable trunk within a trunk(like the 72's do),
    2) The trunk within a trunk would have a pivot point near the bottom and be placed in a position such that the lifting load was balanced and not able to load up the pushrod moving the trunk. Similar to the way the 72's balance the load so as not to overload the control pushrods.
    3) The loads on my system were way over twice the A Cat loads so there is no question that it would work-but is it legal?
     
  8. Baltic Bandit

    Baltic Bandit Previous Member

    Well Doug, actually wands themselves are not legal in the A class even if they move only a flap.

    But a twist grip on a tiller ext would not allow fast enough control to provide heave control Watch the video of the leeward mark rounding again where the boat launches itself. That boat goes from sailing flat to launch in about 1/2 second. and as the boat launches, the driver kinda has his hands full keeping his footing. He does not have much available time or cycles to adjust the twist of the tiller extension.

    Also anyone who has sailed a boat that has such a twist control (I've sailed an I-14 with it) can tell you that you basically have about 120 degrees of rotational control. Now look at the F18 Phantom. to adjust the AoA 1mm at the board head, you have to pull about 6" of line.

    So you would have to have an extraordinarily high rate of gearing to get the tiller to have effective control of the AoA - which in turn makes it almost impossible to adjust.
     
  9. Doug Lord
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    Doug Lord Flight Ready

    A Cat on Foils!

    This video is excellent-answers a lot of questions.

    Nathans points:
    1) yes it is legal to adjust board rake(AOI),
    2) windward board can be uncleated and allowed to rise to reduce wetted surface or
    3) windward board can be adjusted for a negative AOI to add RM,
    4) Nathan says these boats(foilers) are more fun, more exciting and easier to sail than A Class boats were just a few years ago.
    5) Nathan has AOI adjustment rigged so that he can adjust the rake of the leeward board while on the trapeze.

    =================
    Pretty damn cool. Twist grip control would definitely work but an "uptip" foil would make it much more stable if a way could be found to get it in from the top. ETNZ pioneered "uptip" foils would still require manual rake control(like on Groupama). Twist grip would make that much easier to do.

    http://www.youtube.com/watch?v=ikjdzwPo1jI
     
  10. Blackburn
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    Blackburn Senior Member

    .

    The Takapuna Beach Webcam.

    You'd think they'd have a LIVE webcam, wouldn't have cost them more than a newfangled flying pintle?

    <removed>
     
    Last edited by a moderator: Feb 16, 2014
  11. Doug Lord
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    Doug Lord Flight Ready

    A Class on Foils!

    ==========
    What a beautiful place! Even more so with all those foilers flying around changing the world(s)!
     
  12. Blackburn
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    Blackburn Senior Member

    (a couple of posts have vanished, and Coxcreek and I were just having fun!)

    ...

    And, even when the number of Aotearoans and Australians in a race is practically unlimited, you might still search in vain for a sign that one of them can compose a summary of what's happened, and post it on the net.

    But I found that Denmark's Thomas Paasch has been keeping a good diary.

     
  13. Doug Lord
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    Doug Lord Flight Ready

  14. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    A Cat on Foils!

    Final results-top three in light air were foilers. The big news from this Worlds is that every one of the 9 races sailed was won by a foiler:
    http://www.sailingeventstakapuna.co...ss World Championships Final results 2014.pdf

    Report on Saturdays racing from The Daily Sail: http://www.thedailysail.com/dinghy/14/66184/0/a-class-worlds-2014-day-4-report

    ==============
    For technical foiling design info see posts 58 and 59 by Magnus "Blunted" Clarke here: http://forums.sailinganarchy.com/index.php?showtopic=155220#entry4481834
     

  15. Baltic Bandit

    Baltic Bandit Previous Member

    Based on what facts?

    I've already enumerated a list of reasons it would not work. Including that you only have about 120 degrees of a range of motion and human response time isn't fast enough.

    You are also wrong in saying that it is illegal to adjust AoA. its not. What is illegal is to use "external energy" to do that adjustment. And a wand is considered external power source. Moth's get around this by modifying RRS 52 to state that wands are not considered external energy sources
     
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