Evolvement of foiling sailboats over the last 70 years

Discussion in 'Sailboats' started by Angélique, Feb 4, 2019.

  1. OzFred
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    OzFred Senior Member

    To some extent this supports the original proposition. Yes it's crude, but it's the essential components of the AC75 foil system and also similar to that of the Vampire catamaran. But all of these older systems use straight foils, I guess because they just didn't have the materials to build C, J, L or Z foils.
     
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  2. revintage
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    revintage Senior Member

    To my knowledge the today highly regarded NACA 63-412, commonly used for example in foiling Moths, where designed in the late 30´s. A pity it wasn´t used for hydrofoil sailing back then. Even an really old section of the 20´s and 30´s like NACA 2412 or 2512 has attributes that off course places them behind H105 but not by extremely much. 2412 has just 12% lower max speed(38 vs 43 knots) below cavitation and very much closer if we compare Cl/Cd. It´s the materials that have made most of the developments possible.
     
  3. Angélique
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    Angélique aka Angel (only by name)

    Not at all Fred, and you know it since you've quoted a drawing that clearly states 1955.

    ‘‘ . . . . foils themselves have evolved almost nothing in the last 70 years . . . . ’’

    That means almost nothing has changed in all foil design since 1949, which is clearly not true.

    Besides that, many other foil forms next to the inverted T foil have arose in the past decades, especially in the present past due to the availability of new technologies and materials.

    Even the 1955 inverted T foils you quoted have changed in design, as they have have changed in dimensions and angles and have become upwards foldable, so you only have to drag the leeward foil through the water, which makes a huge difference.

    Below a pic from 1:38 in the below vid of the Vampire project you talked about, which shows J foils that are not near ¼ of 70 years ago, literally next to the inverted T foils, which even in the 1955 premature design form you've quoted are also 6 years younger than 70 years.

    Evolvement of foiling sailboats over the last 70 years T and J foils.jpg

     
  4. revintage
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    revintage Senior Member

    The right figure in the sketch above is maybe too hastely drawn, but maybe it was this one you meant to show. A modernized version of the old surface piercing V-foil.

    [​IMG]
     
    Last edited: Feb 5, 2019
  5. trip the light fandango
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    trip the light fandango Senior Member

    The advances in foils are about the 3rd industrial revolution mainly, all along the issue has been anticipating change on the surface or just below it, gps, and chips are why these things can be looked at again seriously, and of course lightweight modern, strong materials, data collection. The revolution is also the ability to share free knowledge easily, such as this forum, foilers are benefiting. Foilers are evolving quicker now with this new technology, the stick out the front reading info each millisecond or they would crash more often,like the good old days, yes that is amazing. I can't see an argument or anyone trying to say this isn't so, because that would just be silly. Air bags, collapsing foils ,something to take the speed out of the inevitable crash is the unsolved final piece to the puzzle isn't it? .
     
  6. Angélique
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    Angélique aka Angel (only by name)

    Below a pic from 1:38 in the above video, that's a complete new design when compared to 1955, only the inverted T form has stayed, so to think it's the same thing is the same as to think cars don't have design changes since Nicolas-Joseph Cugnot's 1769 steam car, since today they still drive on wheels and axes...

    Evolvement of foiling sailboats over the last 70 years 2015 T foil.jpg
    ( ½ of the T is behind the dinghy the foil lies on )

    1769 steam car with wheels and axes
    [​IMG]
     
    Last edited: Feb 5, 2019
  7. revintage
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    revintage Senior Member

    TANSL is not at all wrong, the more than 70 year old NACA 63-412 sections are still used on most foiling Moths. He said "foils themselves". Did you read "hydrofoils on sailboats"?
     
  8. OzFred
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    OzFred Senior Member

    The Vampire images are just schematics, they aren't accurate designs. This is the best I could get of an F50 foil, they have no V at all and are going toward Z foils. But they also have some serious computer and power assistance with controlling just about every aspect of the foils, including how fast they're are raised and lowered.

    So maybe the sections haven't changed much, but just about everything else has.
     

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  9. revintage
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    revintage Senior Member

  10. Angélique
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    Angélique aka Angel (only by name)

    That foil was not used as a hydrofoil on sailboats back then, which we were and are discussing, and even if your twisting is accepted, then the key is in your word ‘‘most’’ and only naming ‘‘Moths’’, these limitations in your expressions make clear that even you know there are foil design changes in use on other foiling boats, such a pity to deny it overall when you know an example that didn't change.
     
  11. Angélique
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    Angélique aka Angel (only by name)

    The only foils we were and are talking about on threads you named are hydrofoils on sailboats, but go on and twist it into other foils and for other uses if you like.
     
    Last edited: Feb 5, 2019
  12. revintage
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    revintage Senior Member

    Oops! Had to remove my previous post, as sinking to your level of argumentation was wrong;).
     
  13. Angélique
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    Angélique aka Angel (only by name)

    Why should you look at it Revintage . . ?

    Since in several posts here you support the idea that foils themselves have evolved almost nothing in the last 70 years.

    If so, why do you expect there's something new to learn . . ?

    Or better, why contradicting yourself in such a way . . ?
     
  14. Doug Lord
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    Doug Lord Flight Ready

    One of the most significant developments in foil design occured in the lead up to the 34th AC where TNZ invented a new type of foil(an "uptip" foil) that was able to maintain the flying altitude of the boat it was attached to with no moving parts and little to no change in altitude due to speed:
    Link to Part 1 and Part 2: America's Cup 2007 2010 2013 - Feature Articles Index - From Cupinfo.com http://www.cupinfo.com/en/featuresindex.php

    Quote from the article,Part 1:

    When we were working on the rule, we knew you wanted to get as much lift as possible when you were going fast downwind,” Melvin says. "For instance, in the 2010 America’s Cup, sailed on giant multihulls, the maximum amount of lift we thought we could get was about 50% of the weight of the boat. At that time, we were still relying on the hull to provide pitch control, so what’s come out of this is the boats all now have elevators (the horizontal foils on the rudders).

    At Team New Zealand, we developed a new type of foil that allows you to keep your height above the water more or less steady. No one had been able to do that before, at least not on a course-racing boat that was not going downwind. We developed that mostly on our SL33 test boats -- they came with the stock constant curvature “C” foils and with those kinds of foils, you can generate 50% boat weight lift before they get unstable. But we noticed that when we could get one boat up fully foiling for a few seconds it would really accelerate away from the other boat – and that got the wheels turning. How, with such a huge potential benefit, can we achieve stable flight downwind? So our design team came up with the “up-tip” type of boards. We refined those on the 33s and our 72 is designed to do that and fortunately it worked right of the box.”
    ====================

    These foils have been used on many beach cats and on larger cats such as the G4. They have found a tremendous application on large(and a couple of small) trimarans where they are used on the amas of Gitana 17, Macif, Banque Populaire and the principle has been applied to angled "L" foils on the 70' Maserati.

    ----picture by DL
    MPX ama + ama = cat --foil comparison 011 - Copy (2).JPG

    ----picture by Team Macif
    Macif in the shed just before launch.jpg

    ----picture by Fred Monsonnec(Foilers!)
    gitana-17-vue-arric3a8re-photo-2-f-monsonnec-04-04-17 - Copy.jpg
     
    Last edited: Feb 8, 2019

  15. revintage
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    revintage Senior Member

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