Mirabaud LX 2010

Discussion in 'Sailboats' started by Doug Lord, Jun 1, 2010.

  1. CutOnce

    CutOnce Previous Member

    I doubt they'd do it. Since there is no one to race against, their goals are different. Any records set by this boat are incidental to Jundt's project. Jundt has crafted an interesting situation here - he's sponsored by a Swiss bank - and the bank's benefits from this is exposure, association with a "think different" and visually shocking on-the-water ambassador and the Teutonic love of engineering in general. Skinning the space frame reduces some of the visual shock and makes the boat look more ordinary - and ordinary isn't good.

    Jundt has stricken a careful and pretty smart balance here - and he's managed to keep a very one-off project alive a long time - so I do not think playing with the formula is going to happen. The more he comes full circle back to a proper boat, the less attention the project gets for being different.

    Adding a wing keeps the project fresh and visually stunning. And that keeps the sponsor happy.

    I'm perfectly certain Jundt already knows exactly what real world changes would be needed to make this boat perform better, but making those changes might kill the golden goose.

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    CutOnce
     
  2. CutOnce

    CutOnce Previous Member

    Doug:

    You see things so one dimensionally. Every project manager has got to balance demands that exceed resources all the time. In a real business, you have to also balance what your bosses want with what the customers want.

    Jundt (if he's half the engineer he has already proven to be) already knows about the aerodynamic inefficiencies of his design - I think I remember him posting comments to that effect. Assuming I am correct about this, Jundt has most likely focused his attention on other details he feels are more significant - learning about the current state of the art with wing technology etc.

    That doesn't mean he has dismissed aero drag as a problem - it just means he feels there is more benefit to be gained from other things. There are deliberate choices made all the time on every project - and often these deliberate choices may hurt performance. When I postulate that Jundt sees value in keeping the package appealing to his sponsors I am acknowledging that he's smarter than the average bear in Jellystone Park.

    Here is where your on-line discussion-based projects come into conflict with real world, real money, real effort projects. It doesn't cost you anything to choose to go with every possible improvement and feature in your discussions. In the real world, you often have to pick and choose what you can do, what you can afford, what your bosses want done and what your customers must have. Jundt has already secured third party funding for state of the art wing development - by Fredo's numbers this means he's probably into it for hundreds of thousands of dollars on that front alone. I doubt he's got endless budget to pursue too many other things at once.

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    CutOnce
     
  3. Magnus44

    Magnus44 Previous Member


    I happen to agree with your summary, Cut. There is a definite reluctance in the program to create a boat that is a true world beater in terms of performance. The surface drag of the "hull form" in the air is extraordinary and not a bit of development energy has been dedicated to solving that problem. Instead, they have tinkered with incidentals while the elephant in the room goes plodding around, unnoticed.

    Clearly, the hull structure clean up is off limits and very much a taboo subject in that camp. It is something like flying a Sopwith Camel with a turbofan engine while beating lesser powered, smaller aircraft. This practice does not look like a victory of technology to me.

    Jundt must have something better to say for himself than to be confined in this fashion.
     
  4. Magnus44

    Magnus44 Previous Member

    You suggest that I have not done any reading on the topic. That assumption would be untrue. I do happen to hold a different opinion than yours and find the comments being made by Cut Once to be much more in line with the process engaged in professional circles when it comes to solving issues such as those being discussed.

    I am concerned that you choose to change the tone of the conversation. Making humorless comments that are loaded with negative innuendo could be construed as a personal attack. It is my opinion that this use of the language is not necessary.

    I ask that you refrain from this form of conversation.
     
  5. CutOnce

    CutOnce Previous Member

    Rather than talk more crap ....

    Doug:

    Time will tell. My thoughts are based on Mr. Jundt's project performance to date, and an understanding of the sponsorship and funding climate. If you are right, Mr. Jundt will spend money faster than Charlie Sheen and approach all possible performance improvement avenues concurrently.

    If I am right, we'll see incremental prioritized changes progressing carefully, while keeping budget, sponsors and resources all happy and managed. Mr. Jundt appears to be focused on developing wing sail technology right now.

    It would be interesting to have Mr. Jundt read this thread and comment on the observations within. He's perfectly capable of stating his own positions without your help.

    Notice how I can comment on your post without personal attacks or attempting to denigrate your intelligence and experience. It is a skill you would do well to learn.

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    CutOnce
     
  6. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

  7. Magnus44

    Magnus44 Previous Member


    Complete agreement. Even with a wing, the boat will remain slow relative to its supposed potential. This is mostly due to the excessive aerodynamic drag of the space frame surface area and exposed wing rack structure.



    Quite so and I invite Mr. Jundt to engage the discussion.



    Argumentum ad hominem http://en.wikipedia.org/wiki/Ad_hominem
     
  8. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    Mirabaud

    -------
    Gary,there have been countless developments occurring at a rapid pace over the last few years. It seems to me that the areas of development that Thomas has concentrated on all have a major bearing on the structure and design of the boat and that since that development is not yet complete adding a streamline structure would have been ,and may still be, premature. As an example: the position of the daggerboard on this boat is like no other successful foiler-ahead of the mast. The other successful high speed boats that have used such an arrangement, that I know of, are Bill Roberts' Arc 21 catamaran where he put the daggerboard ahead of the main beam-calling it "shared lift". The fact that Thomas tried this successfully is a testament to his ingenuity and ability to innovate. On a foiler this increases the pitch footprint adding to pitch stability. But it also required a major structural change which would have been greatly affected in terms of time, cost and materials if such a change had to include re-doing some sort of aerodynamic cover. If you've read Bill Beavers treatise on the Moth you know that while aerodynamic drag is higher than anybody thought, 42% of it is a result of the drag of the crew(see "Air Resistance" in document below). On Mirabaud, that drag is bound to be a higher percentage of total aerodynamic drag with three crew- reducing the possible gain to an area that definitely has a lower priority than foils, foil placement, hull(s), rig and most important of all :light weight for a given structure.

    >picture worth a thousand words: note daggerboard position, note wand(s) AET on left Mirabaud on right= same project from then to now:

    (click on image)
     

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  9. Magnus44

    Magnus44 Previous Member

    What is it they say over on Sailing Anarchy's Forum when something is posted over and over again? I believe it is, Groundhog Day, in honor of the Bill Murray film where the protagonist lives the same day over and over.

    There are many very intelligent people on the BD Forum. It is not necessary to repeat oneself in order to make a point that wasn't correct the first time it was displayed. To do so runs the risk of insulting the reader.
     
  10. Gary Baigent
    Joined: Jul 2005
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    Location: auckland nz

    Gary Baigent Senior Member

    Agreed, Doug, the forward foil position is breaking the rules ... but that is a thing with foilers, this unconventional thing occurs, not in the book; theoretically the platform should be completely out of balance with terrible weather helm. And agreed again, the drag from humans stacking/trapezing out in the high pressure area on racks causes major drag too. In my humble opinion, these drag areas need to be considered if high performance, both to windward and hard reaching, is seriously considered. Mirabaud has large potential ... but they have to consider drag as a very important element - if they really want to travel fast.
     
  11. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    Mirabaud

    Gary, here is what Bill Roberts says about his "Shared Lift" concept on the Arc 21 cat:

    The ARC-21 utilizes Bill Roberts "Shared Lift" concept in conjunction with low drag, high lift daggerboard and rudder designs that not only improve the ARC-21's windward capabilities but also produce a balanced helm off the wind even when flying a spinnaker. Coupling the ARC-21's "Shared Lift" daggerboard design with its high-efficiency and powerful sail plan produces a combination that will sail higher and faster to windward than any other 8.5ft. wide beachcat on the market. No other beach cat is designed like this, the daggerboard is forward of the main beam and is smaller in area than the rudder, thus the basis for "Shared Lift".

    I think this is what Thomas has done with similar benefits.

    http://www.aquarius-sail.com/catamarans/arc21/index.htm
     
  12. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    Mirabaud

    Heard from Thomas: no plans at all to "streamline" the boat. Said that he will save that until the next boat......
     
  13. Jundt
    Joined: Sep 2006
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    Location: Geneva Switzerland

    Jundt Owner foiling 18 AET

    Hello CutOnce

    You asked me to add something to the discussion about aerodrag.

    Well yes the spaceframe + wings + styrobags + hull + crew is quite draggy, i must admit.

    But then to understand the Mirabaud LX one has to remember the initial aim of the thing, back in 2007

    On our lake we try to sail in thermal winds something between 5 and 12 knots TWS. The only way to be home before night in regatas is by investing in either a Psaros 40 (big canting keeler monohull 24 m mast,etc 500 k$ ) or catamarans M2 (250 k$) or D35 (700 k$)

    But I like to do it my way (have to do it my way, no spare change for big boats)

    We have been sailing for 20 years (same crew of three) on an 18footer and we like the light weight sailing and trapezing. My thoughts went for trying to improove light wind performance of the 18footer and i ended up trying the foiling. I was looking for big foils for flying with as few wind as possible, top speed was never a goal. Main goal was high average speed eg. flying as soon as possible.

    Therefore the new prototype had to be :
    - as light as possible (total obsession)
    - no hull = weight saving (juste something for take off and landing)
    - amateur construction
    - as cheap as possible
    - keep 18footer rig, wings, foils

    I ended up with the space frame for several reasons:
    - easy to build, off the shelf tubes (well the shelf was in NZ)
    - light, only 35 kg, and very stiff
    - i could not make up my mind for the hull shape (actually I am at the third hull today)
    - Hull = Styroblock with .2 mm of laminate = Kleenex no structural value, easy to build
    - Hull + frame = 80 kg not too bad, good cost/weight ratio

    To bring it down to 60 kg and reduce drag : It had be a monocoque hull with lots of molds to build, with prepregs and autoclave and a lot of high tech etc and at least 200 k$ to spend !!

    So here is the answer 200 k$ or drag.. i keep the drag

    Note that compared to a moth the loads from wings and rig are sustantially higher (mast foot compression 2200 pounds). Therefore a monocoque hull resisting to these loads, brougt down to 60 kg would be a master piece of composite engineering - Too complicated for an amateur week end sailor - As a space frame is 1st year engineering school exercize

    Why do i try a wing ?

    I am at the end of amateur developement of the boat as it is, to make it better we had to
    - make better foils but i needed to learn hydrodynamics..
    - make a better hull, as i said too much money
    - improove the crew ? no way we are getting old and fat

    So the main reason to build a wing is ...

    Why not !
     
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  14. CutOnce

    CutOnce Previous Member

    Thomas:

    Merci pour votre bonne mots de sensibilite.

    It is wonderful to get the project objectives and intelligent compromises and choices direct without the distortion filter of someone else's agenda.

    I think your project is wonderful, as it continues to develop and meet YOUR dreams. You obviously are having fun with your friends of 20 years, and you have kept the fun of sailing on your lake in your local conditions as the primary criteria for success.

    Too often on this website we are subjected to foiling "news" and performance topics presented by third parties with their own agenda and "spin" on things. Frequently this skews things far from the actual builder's purpose and intent, but promotes the third party's own perspective.

    Your statements regarding your project have outlined the challenges faced and decisions made regarding your project clearly. Given the reality of working within a budget and choosing one or two areas to focus on (within many possible areas of improvement) I appreciate the logic of the choices made.

    I hope you have a great season and lots of fun sailing with your friends. Best of luck with the wing development and I really appreciate your project updates on your website.

    --
    CutOnce
     

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

    Doug Lord Flight Ready

    ================
    Thomas, thanks again for posting in this thread! Best of luck with the wing
    and racing this year.
    PS- looking forward to the "next boat"!
     
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