Little America's Cup 2010-C CLass-the real one..

Discussion in 'Multihulls' started by Doug Lord, Apr 12, 2010.

  1. TTS
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    TTS Senior Member

    Tom,

    Thanks for posting that. I guess that I should be able to figure out how to post it. Not bad with computers, so I probably just didn't take the time to make it happen.
     
  2. Doug Lord
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    Doug Lord Flight Ready

    Little Americas Cup-----watch live!

    Hopefully, we'll be able to watch at least some of the races live here:

    http://littleac.com/


    ====================================
    See post 14,page 1 of this thread for Steve Killings great paper on C Class cats including Rocker the C Class foiler....
     
  3. Doug Lord
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    Doug Lord Flight Ready

    Litlle America's Cup

    Here's some analysis from Steve Clark(sa):

    Alpha is very similar to Cogito, but a bit lighter, and the wing is a bit taller. Not alot of risk there and it establishes his program with a base line very good boat. Since then he has built and tested a hydrofoil, and an aggressive wave piercing platform against that excellent baseline. He has concluded that those lines of exploration don't pay out as they expected, so they have then gone back to a further refinement of their base concept.
    This isn't conformist, it's actually rational and scientific and the way most progress in the world is made.

    I build fewer boats than Fred, and so have to try to take bigger steps. My new wing has an expanded twist control system, a different approach to the flying surfaces and slightly modified flap geometry. That's more innovation than I could ever introduce in one product cycle at Vanguard because it is risky. The platform has a significantly different hull form from a no name designer and a different foil configuration than what anyone has seen. I haven't had time to sort it all out yet and be sure what is the best setting for any given set of conditions. So I am going to be fumbling around on the race course trying to find the go buttons when Fred will be looking for the shifts and sailing fast. My only chance is that the new boat is faster, because I know Fred will be racing better than I am.
     
  4. Doug Lord
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    Doug Lord Flight Ready

    Little Americas Cup-------New wing out!, part 1 of 2

    In a most unfortunate development Steve won't be able to use his new wing:

    Now some bad news for you sports fans. Aethon's new wing will not make it to Newport. We had our first sail yesterday and it was not an unqualified success. Oliver and I are convinced that it will be very fast, but a number of interlinked structural and control system problems need to be solved. This cannot happen in the next 3 days and give us any confidence that the boat will be able to complete the regatta. As a result we have had to make a tough choice or two. The upshot is that Cogito will not sail. We will use her wing on Aethon. In the spirit identified above, I will post some pictures of the first sail and some explanations of what I believe is happening.

    I am not happy about this, particularly after the hours that Sam and Oliver have been putting in to complete the project. I also feel that I have let down Paterson, Rossi and the other Canadians who worked long and hard to reconstruct the 007 wing after it's assassination attempt failed. The show is a bit less grand, but will go on.
    SHC
     
  5. Doug Lord
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    Doug Lord Flight Ready

    Little America's Cup----New Wing Out!, part 2 of 2

    From Steve on sa:

    So here is the tale:
    The new wing had a couple of things that seemed worth trying and required some new solutions.
    First was the thought that we could save a significant amount of weight by letting the whole thing be more flexible.
    This would mean that the wing below the hounds would sag to leeward like a DN iceboat rig. We don't want to be that radical, but inherently there is nothing wrong with letting the rig sag as long as all the elements sag at the same rate. Associated with that thought is the idea that if the spans are shorter, it is easier to assure that all the elements sag at the same rate and that the #3 flap leading edge spar is much less stiffness critical and can also become lighter. The main spar was was built with this in mind, the laminate was reduced and the diameter was reduced to what we projected to be a safe minimum. It turned out that we were wrong on our original calculations, and that the mast wasn't stable when we tested it to it's projected full compression. We had to add laminate, and this gave back half the weight we hoped to save. We scrambled to redesign the hounds and mast base to minimize the prebend they imparted into the tube. That took a while.

    We also felt that it would be advantageous to twist the entire span of the wing instead of just the bottom 25 feet ( as per Cogito)

    The cost of doing this comes with complication, in order to have an intermediate control arms you have to build ones hat is not glued securely to the main mast, but which rotates proportionately with the twist mechanism. Thus if the top of the wing is a 12 degrees and the bottom is at zero, the two intermediate arms have to be at 4 and 8 degrees respectively. I wanted this to be self tacking and not require an additional layer of wing controls. I spent a lot of time mucking around but devised a fairly simple series of wheels and cams that would achieve this end. Fabricated it and got it working well in the shop.


    A third goal was to improve the quality of the flying surfaces. The shrink film is effective and very light, but as the video from above shows, it is very stretchy and here are losses associated with the distortion of the flying surfaces. I haven't found any literature on this. It is just an observation and something I thought worth doing. So I planned to skin the new wing with very light composite panels ( weighing in the neighborhood of 0.10 lbs/ft^2) and reduce the internal structure to a minimum. The aerodynamic loads are really very small, and the compression loads imparted by the shrink film are relatively large. We reasoned we could save weight and get superior aerodynamics.

    Last weekend we weighed the wing, and were pleased with the 141 pound weight. We put it up, and the controls all worked as designed. This was looking like a home run. All it had to do was behave when it was fully loaded, and the only way to find that out was to go sailing.

    At this point all the time we wasted in he last 2 years bit back hard. If there was any significant problem, we were ******. There wasn't time to fix it. So we went down the list as if we were going to sail out to the race course right from the shop. Our first impression upon hitting the water was "WHO-ho!) the wing felt very slippery and clean. The efforts to reduce drag were obviously good. and even with two of us sitting on the hull, we had nice speed.
    Then we started to notice that the surfaces were distorting and buckling in interesting ways.
    Our old friend stretch had come back to haunt us and as a result, parts were being loaded in ways that they shouldn't be loaded. The first and most obvious one to be damaged was the #3 flap at boom level. Because the camber and twist cables were stretched, this element was being asked to do more than its fair share holding the main sheet and the flap up. The core sheered and it started to look increasingly like a beer can. By the end of the sail, it was pretty clear that we would have substantially rebuild the bottom of our 3# element. It will be faster and better to build a replacement than to repair that one. We don't have time for that.

    A second series of issues showed up around the span wise sag of the mast. In order to twist and sag, these skins are held in place by slots and pins. This allows them to duck and dodge as they get loaded in various ways. We needed more relief than we had installed. As a result the leading edges sustained some damage that, while not game ending, will take some time to repair properly, and time is something we don't have. It is going to take a bit more sailing and testing before we understand the best combination of solutions.

    Finally we have under-specified the ribs in our #2 element, particularly down near the bottom (where they are longest.) These need to be reinforced with gussets and some bulkheads. Once again, a fairly trivial fix but not something you do right in the next 3 days on top of everything else.

    The final bug bear is the stretch in the control system. We were conscious of this all along and sized our cordage for stretch more than strength. In retrospect, I should have gone old school and done it all with wire. But I get carried away by the miracle that is modern line and thought I could go straight to the end game. Bad judgement on my part. I know we can sort this out, but is is going to take some time and we will probably trash a few more surfaces as we do. Knowing that there is an end, and getting there is just a matter of time. We are out of time.

    So the take away is that I believe we have a good idea. We tried about 3 things too many at the same time, and ran out of time to get them working well enough in concert to go racing. Unfortunately, they are all linked, and you don't get one without the others. The weight saving is contingent on the control system working, and the skins are critical to the weight savings. We feel that the wing has enough potential that we didn't want to start down the road of half *** ed jungle repairs. We feel that if we do that, we can likely throw away too much of the work done over the last 6 months and end up with a piece of junk. If on the other hand we proceed thoughtfully, we could have a superior wing and the basis of future development. So we have to endure short term disappointment in the hopes of long term advancement. This is the kind of decision we ought to make as adults. But GODDAMNIT.
    SHC

    Beatings will continue until morale improves.


    Note the spanwise sag-like an iceboat- in the left picture:
     

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  6. Doug Lord
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    Doug Lord Flight Ready

    Litlle America's Cup---Aethon

    I'm very disappointed for Steve and his team-what an unfortunate turn of events. They still have Cogitos wing and those tricky foils. They can still win and I hope they do! Good Luck, Steve!
     
  7. Doug Lord
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    Doug Lord Flight Ready

    Litlle America's Cup-the Brits are here!

    And a fitting picture that tells the whole story:



    Invictus with Aquidneck...


    (click on image and then again on image that results)
     

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  8. Doug Lord
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    Doug Lord Flight Ready

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

    Little America's Cup

    New pictures(last two pages) : http://forums.sailinganarchy.com/index.php?showtopic=101656&pid=2964345&st=875&#entry2964345


    Live broadcast url(and schedule) : http://littleac.com/LITTLE_AMERICAS_CUP-WELCOME.html
    ---------------
    COMPETITORSBoat Sail # Helm Crew
    Canaan CAN 009 Fred Eaton Magnus Clarke
    Aethon USA 002 Steve Clark Oliver Moore
    Invictus GBR 001 Paul Larsen Helena Darvelid
    Patient Lady VI FRA 002 Antoine Koch Jérémie Lagarrigue
    Alpha CAN 004 Glenn Ashby Jimmy Spithill
    Orion CAN 002 Dan Cunningham Rob Paterson


    ------------------------

    SCHEDULE
    Aug. 15-22 Facilities at Sail Newport available for training
    Saturday Aug. 21 Measurement at Sail Newport by appointment
    Sunday Aug. 22

    1830
    Measurement at NYYC by appointment

    Registration at NYYC Sailing Center

    Competitors meeting at NYYC Sailing Center

    Opening Reception
    ------------------------------

    Monday Aug. 23 1100
    Warning signal for the first fleet race
    -----------------
    Tuesday Aug. 24 1100
    Warning signal for the first fleet race
    -----------------
    Wednesday Aug. 25 1100

    Warning signal for the first fleet race

    Cocktails & BBQ Dinner
    --------------------

    Thursday Aug. 26 0900

    1200
    Meeting with the Umpires (for top two teams)

    Attention signal for the first match race
    -------------------

    Friday Aug. 27 1100 Attention signal for the first match race

    Saturday Aug. 28 1100

    TBD
    Attention signal for the first match race

    Final Awards ceremony after racing

    Sunday Aug. 29 Break down and departure
     
  10. Doug Lord
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    Doug Lord Flight Ready

    Little America's Cup

    Control complexity----nah......




    pix by John Casy-posted on SA:
    (click once and then again)
     

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  11. TTS
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    TTS Senior Member

    Doug,

    The British wing looks great. If you look between the three Canadian wings, Aethon's new, but un-usable one, Inviticus's and the older PLVI wing you have many differing design thoughts. This is just great to see. Aethon's seems to be a further evolution of the original Cogito wing. Caanan's new wing seems to be a highly refined evolution of USA-17's wing. Both Alpha and Off Yer Rocker's wings are based upon the Cogito principle but higher aspect and narrower in cord. I do not know how to describe the Inviticus wing, but I like it. When you get aeronautical engineers together, you never know what you will come up with. If or when I have the money to enter the C-Class, I think that I would approach Pete Melvin from Morelli & Melvin for design and Lars Guck for boat-building. Pete is just one of those rare minds who understands more than I could ever know and Lars is a builder extraordinaire. He has worked on a couple of my boats in the past and has done phenomenal work. I have looked over the many different projects that he has completed and I think that he is one of the best out there. Lars took over the building of the A3 A-Cat designed by Pete Melvin and Jeremy Laundergan and I believe that even without the use of RIF technology he is building stiffer, lighter and better platforms than the other builders. In addition, he has been involved in many different ways with Steve Clark and the C-Class as well as other projects with Steve over the years. If anyone out there is looking in the Northeast for either a builder or a company to maximze their boat for racing, Lars Guck at GuckInc is the place to go. Pete Melvin needs no introduction from his state of the art designs to his ongoing involvement with the America's Cup to projects like Gunboat or the Nacra F20 and M&M A3. What a great mind. Anyway enough of advertising and testimonials for others, I just want to be able to support a C-Class campaign. I have looked at these boats since I started looking at building a catamaran in 1980. It took me until 1987 to decide what to build and that was my first Tornado. We looked hard at the C-Class back then but while my partner, Ken King (founder and mind behind NavTec Rod Rigging) could afford to be involved, I could not even begin to afford it then or now (for the moment). In 1988 Chefs did not make that kind of money, well even now most of us mortal chefs still do not. I can keep dreaming though and one day I will make those dreams happen.

    TTS
     
  12. TTS
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    TTS Senior Member

    Yes the lots of lines and only one small hole picture. Some of the other photos are great too. Like the one with four wings hanging in the tent together. There are also some great shots of the boats sailing and baots being set-up or broke down posted on SA.
     
  13. Doug Lord
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    Doug Lord Flight Ready

    ========
    Great posts Tom! Thanks for the info and insight-I wish I could be up there.
    The wings interest and fascinate me but I wonder how they would compare to a highly refined soft sail rig like the Moth or A Class. We sort of know the answer with Halls wing... And would a C Class monohull bi-foiler be the fastest form of C Class? All extremely interesting to me. Have fun at the races-I'll be tuning in to SA's coverage.....
     
  14. Doug Lord
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    Doug Lord Flight Ready


  15. Doug Lord
    Joined: May 2009
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Last edited: Aug 27, 2010
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