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Thread: Birdwing mast design to benefit from new sail track composite material

  1. #71
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by kenjamin View Post
    That's not exactly correct, Chris. I stated the patent's definition of what a birdwing mast is and then asked the question "How can it not be aerodynamically efficient and still be a birdwing?" The difference may seem subtle to you but if it doesn't utilize an aerodynamically "efficient" cross section in its curved part, it isn't a birdwing mast. If it doesn't have an overall shape of a sickle and be able to present curvature along the entire length of the mast in the airflow, it is not a birdwing mast. If it doesn't freely rotate under wind power alone to best take advantage of the direction of the airflow, then it isn't a birdwing mast.

    Anyone spending the money to put a carbon fiber birdwing mast into production will pay generously to ensure that the aerodynamically efficient cross section used in the production of the mast will certainly be "aerodynamically efficient" for real. Like I said before, I will not be the one making those decisions because I am not qualified, trained, experienced, or even have the slightest idea of the best way of creating an aerodynamically efficient carbon fiber birdwing mast. I am happy to leave that up to the experts and isn't that what you wanted from me all along??? I was just the guy who thought of the idea of the thing and eventually got a U.S. patent on it. Just because the patent was mainly issued as a utility patent for its ability to store better in the average boat, any mast manufacturer who hopes to gain patent protection for the design (while they develop it) must also meet the specifications of efficiency described in the patent or it would not be a birdwing mast and therefore would not receive the protection from competition the patent can provide.

    My personal opinion is that the birdwing mast will prove to be extremely efficient or at least it can be given its established definition but I will gladly leave the aerodynamic efficiency claims to the manufacturer brave enough to attempt a carbon fiber birdwing production. I also believe the birdwing mast can look pretty cool too and for that I am bon-a-fied. I got me an art degree.

    Rendering by JF Bedard Yacht Design:

    Yes, your meaning was unclear, because you still make claims about the aerodynamic efficiency of the birdwing as if it were a fact rather than an opinion. Secondly, the way you state it means that no birdwing mast may currently exist, and yet you keep on talking about having built them.

    You say "unless it has an aerodynamic efficient section it's not a birdwing mast" and yet you have not yet proven that the masts you have built have aerodynamic cross sections. Therefore they are not actually proven to be birdwing masts by your definition, yet you keep on referring to them as such. If someone put your masts in a wind tunnel tomorrow and proved that they were not aerodynamically efficient in their cross-section, then by your definition they are not birdwing masts. In that case why do you keep on referring to them as being birdwing masts?

    To word it slightly differently, if being called a "Birdwing mast" requires a certain condition to be satisfied, and that condition has not been proved to be satisfied, then the masts you have built may not be Birdwings by your own definition.The fact that you keep calling them Birdwings therefore indicates that you DO believe them to have satisfied that condition, and yet you have not proven it.

    Secondly, if you are not qualified to find out whether a section is efficient in aerodynamic terms, then why not either withdraw the claims that your section is efficient, or become qualified enough to actually be able to take a stab at it? Why not read Speer's work so you can tell us why the sail/mast lee side interface is more efficient? Why not read Bethwaite's discussion on wingmast aerodynamics? Why not learn the basics about the subject you are hoping someone will spend money on?


    By the way, I've said earlier that it's a pretty mast and a useful one.
    Last edited by Chris249; 08-01-2017 at 08:27 PM.

  2. #72
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by SNAPMAN View Post
    I looked at your patent and am a bit perplexed. You have a total of one claim:

    1. A sail supporting assembly for a sailing vessel having a
    hull with a keel and gunwales, comprising 14 elements a. through n. They are in the form of a list a and b and c......and n.

    If I understand patent claim construction correctly, the only invention covered must contain all of those 14 elements. So if I build one and it doesn't have a curved sliding mast extender as described in m. and n. there would be no infringement according to law. Or as b. states the rotating mast must be perpendicular to the keel, one could have the mast at a 2į angle to the keel.

    You have been beating the birdwing mast drum for at least 7 years.

    I don't see any interest or commercial activity of any similar designs outside of the USA.

    And I don't see anyone stating they want to build one in the US where you patent is in effect.

    Perhaps instead of hoping someone will infringe and you can enlist lawyers to fight over your patent pro bono in order to generate publicity for you, you might consider another path. Opening your patent up to royalty free use for individual builder/users (while reserving commercial rights) who might want to experiment in order to gain some more working examples, visibility, experience and hopefully advocates and ultimately a market for your design.

    In any case IANAL, so this is just my personal observation/suggestion.

    Alan
    https://sites.google.com/site/helium12sofsailboat/
    It also makes one wonder how anyone could take action over a patent breach, because the defendant could probably just use a different definition of "aerodynamically efficient". And of course there's at least one other example of a mast that is cranked forward and curved (at least when in use) as prior art, and perhaps two of them.

  3. #73
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by SNAPMAN View Post
    I looked at your patent and am a bit perplexed. You have a total of one claim:

    1. A sail supporting assembly for a sailing vessel having a
    hull with a keel and gunwales, comprising 14 elements a. through n. They are in the form of a list a and b and c......and n.

    If I understand patent claim construction correctly, the only invention covered must contain all of those 14 elements. So if I build one and it doesn't have a curved sliding mast extender as described in m. and n. there would be no infringement according to law. Or as b. states the rotating mast must be perpendicular to the keel, one could have the mast at a 2į angle to the keel.

    You have been beating the birdwing mast drum for at least 7 years.

    I don't see any interest or commercial activity of any similar designs outside of the USA.

    And I don't see anyone stating they want to build one in the US where you patent is in effect.

    Perhaps instead of hoping someone will infringe and you can enlist lawyers to fight over your patent pro bono in order to generate publicity for you, you might consider another path. Opening your patent up to royalty free use for individual builder/users (while reserving commercial rights) who might want to experiment in order to gain some more working examples, visibility, experience and hopefully advocates and ultimately a market for your design.

    In any case IANAL, so this is just my personal observation/suggestion.

    Alan
    https://sites.google.com/site/helium12sofsailboat/
    I'm not a lawyer either so I can't address your view that the patent has no real power. I've also read an article in Wire magazine that described hostile takeovers of seemingly perfectly conceived and well-written patents that just flat out get stolen by companies with deep pockets that are able to profit tremendously from a patented design while just tying up the inventor and his or her lawyers for years on end until they just give up. I also had a friend that I sung with as a barbershop harmony singer and he invented the thin material chopping mat for kitchen work. He was tied up in court for years defending his patent but eventually was successful in his patent defense and all court costs were awarded as well but he told me the whole experience was a real pain in the you know what and that he could never regain the time he spent defending the patent.

    When FSU got the patent on my design, I really thought my work was over. I thought that FSU would surely generate hard wind tunnel evidence of the design's characteristics and they would publicize the results and find a company interested in building prototypes and I would be getting a royalty check from the sale of the patent rights. Instead the man in charge of the wind tunnel threw me out of his office when he realized that his redesign of my design was not sitting well with me and he said that I was insulting him by not bending over backwards to please him. The guy had a temper. Oh well, such is life. Sometimes you just got to roll with the punches.

    You make some very good points about how to proceed from here but I'm not quite ready to turn the design into a free-for-all design fest. I would have people building stuff that they called a birdwing mast but wasn't. I'd have people building examples that didn't work worth a hoot. I'd have to deal with more people than a retired guy would want to deal with and the list goes on from there.

    I am happy at my snails pace. I like having quality control over what is considered a birdwing mast. I like that when you do a search for birdwing masts, you get mostly examples of my work. I like being the only one who builds boats and sticks birdwing masts on them. I'm financially OK so there's no real pressure to succeed immediately. And I am very much enjoying my retirement from FSU where I worked for 37 years. I've finally got a web site, birdwingmast.com, so something may eventually result from that. I'm trying but as a grumpy old retired guy, it's got to be on my terms not someone else's.

    I've learned a lot over the years and who knows I may end up building small beautiful spruce birdwing masts for kayaks or something like that. I could probably do that well. There's also a new idea brewing that may lift the design out of obscurity and make them much more desirable but if I blab about that now it would be too easily stolen so, silly me, I find reasons to be optimistic. I get to take my 26 mile bicycle tour of St. Augustine anytime I want, I do a little oil painting, I build boats. Life is pretty good for me. If I ever make any serious money as a result of the birdwing mast, I surely won't have any problem spending it but I'm pretty much grateful at my age to be sucking air everyday and standing vertical when I get out of bed in the morning.

    Thanks for adding to the discussion. You make some very valid points.
    Last edited by kenjamin; 08-01-2017 at 08:52 PM.

  4. #74
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by kenjamin View Post

    When FSU got the patent on my design, I really thought my work was over. I thought that FSU would surely generate hard wind tunnel evidence of the design's characteristics and they would publicize the results and find a company interested in building prototypes and I would be getting a royalty check from the sale of the patent rights. Instead the man in charge of the wind tunnel threw me out of his office when he realized that his redesign of my design was not sitting well with me and he said that I was insulting him by not bending over backwards to please him.
    So you or FSU did get hold of an aerodynamics expert, and you refused to listen to him? Why?

    I still can't find a copy of the David Thomas sketch published in Yachting World magazine which, if I recall correctly, showed a mast cranked forward and with an aerodynamic curved section above the cranked section. I can however find a copy of a later plan of the dinghy "Sly", published in the same magazine, showing a mast cranked forward from the base and which would have been curved in use.
    Last edited by Chris249; 08-02-2017 at 05:43 AM.

  5. #75
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Chris,

    This would be a lot more fun for both of us if you would attack me for stuff I actually said rather than stuff you thought I said or stuff I "seemed" to have said.

    What I actually said was the birdwing mast does not exist yet IN ITS FINAL FORM.

    In its final form it will utilize the most "aerodynamically efficient" cross sections that money can buy. Even more importantly it will be as thick as it needs to be at the bottom and smoothly and continuously taper to as thin as it can be at the mast head. The tricky part is not the aerodynamic cross sections. It's the taper that is almost impossible to do correctly along the curved surface of the birdwing mast. If you could get the taper correct in carbon fiber construction, then you'd really have something.

    In my opinion (please notice that this is an opinion, not a claim), it is only very recently that such a perfect taper could actually be achieved in carbon fiber construction.

    When I hired JF Bedard of Bedard Yacht Design to draw a birdwing mast in three dimensional space for the very first time ever (for Muri-Maru), he utilized a NACA cross section but then stretched it or shortened it to match approximately the shape of my latest spruce birdwing prototype. The taper on my latest spruce prototype is lumpy and bumpy but the taper on JF's 3D rendering is as close to perfect as you are ever going to see. Why should I hire JF to do the rendering when surely I could buy a new more powerful computer, buy the latest version of Rhino software, and just learn to draw a 3D birdwing mast all by myself? The answer is simple, TIME. It is time that I'm running out of, not expertise. Expertise you can go out and buy. You could always borrow the money and buy the expertise of the most knowledgable, most trained minds on the planet. It's time that is difficult to buy.

    The patent only has about 12 or 13 years life left in it, and coincidently, that's about the same amount of time this old body of mine has left in it as well. To build the perfect carbon fiber birdwing mast at the rate I'm going, it's probably going to take every one of those years to do it. So you see, I do not really have the time to waste answering remarks about stuff you thought I said or stuff that I "seemed" to have said. You can copy and paste sentences I've written accurately and precisely so let's not waste our time discussing anything otherwise.

    You are absolutely correct in pointing out that most of my birdwing prototypes are not, technically speaking, birdwing masts. But every one of them was a birdwing mast prototype. Inventors' prototypes are hardly ever even near how good the invention becomes in its final form. Maybe the guy who invented the "pet rock" got it right the first time but all the rest of us have to struggle building imperfect prototypes and learning from each and every one of them. And I'm running out of time! I really do not need to learn anything else, I just need to find a manufacturer who can build JF Bedard's perfectly tapered carbon fiber birdwing masts (and figure out how to pay them) and then I will have arrived at the point in time where I have been headed for the last ten years!!!!!!

    Last edited by kenjamin; 08-02-2017 at 09:04 AM.

  6. #76
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by kenjamin View Post
    You make some very good points about how to proceed from here but I'm not quite ready to turn the design into a free-for-all design fest. I would have people building stuff that they called a birdwing mast but wasn't. I'd have people building examples that didn't work worth a hoot. I'd have to deal with more people than a retired guy would want to deal with and the list goes on from there.
    Kenjamin,

    I fully understand your feelings on your invention. You want to make sure your patent is respected and no one tarnishes it with inferior junk.

    But you raise another question: Do you have a trademark on "birdwing mast"? if not, anyone can use that term. And "birdwing" is already used to describe sails, so trademarking it might be tricky, if possible at all.

    In terms of people building copies, in reality, you can't stop them. Anyone in non-USA can do so with zero liability and zero accountability, by your own word in the post I first quoted. You even seem to actively encourage it. In the USA, as you state you would have to sue and might be tied up in court for years and even then the outcome is not guaranteed. Should you win, getting the other party to pay is not a given.

    Notwithstanding whatever deals you are working on (and I do with you luck with them). It seems to get ahead of the curve you might want to be a tad more active. Maybe drawing up some plans for the rig and selling them with a license to build one example would encourage others to take more of an interest and generate a few pennies at least. Of course, maybe you are happy with things as they are, but that seems not too likely based on the amount of time you are writing about it here.

    Best Wishes,

    Alan
    https://sites.google.com/site/helium12sofsailboat/

  7. #77
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Ken; I wasn't attacking you for something you "seemed to have said". It was merely that you were not making it clear that your current masts are actually not, technically speaking, birdwing masts.

  8. #78
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    I would be curious to see what sort of tweaks/ "redesign" the FSU aerodynamics expert suggested to the BW (Bird Wing) design.


    I could see a rig like this, possibly with mounting kit/system being very popular with SUP's and paddle boards... oh shoot...

    ...yeah as i was typing this I realized i had just re-invented a windsurfer... but possibly the BW made available as an aftermarket thing for people who buy an SUP and get bored of just paddling.
    Last edited by Daniel Noyes; 08-02-2017 at 11:06 PM.

  9. #79
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Wing masts didn't work in windsurfers apart from one particular performance. They got an advantage because they offered more stable sail shape, then camber inducers came along and provided the same sort of stability with better gust response.

    Gust response is hugely prized by windsurfers because you physically load up the back arm so easily. There is an international system for measuring mast bend and sailmakers spend eons matching bend to luff curve to get the sail to flick open at the head in the right manner. People are dealing in millimetres; something with compromised bend characteristics (and a wing mast is basically inherently compromised as far as bend goes because it needs certain wall thickness which commonly leads to excess stiffness because of the higher moment of inertia that comes with the wider chord) just won't work. And of course cambered sails with luff pockets already have good airflow characteristics.

    The rigs created for SUPs are very different to the rig pictured, and often much more like the rig for the original Windsurfers. The lift/drag characteristics of a SUP are very different to those of the shortboard pictured and so are the conditions they are used in. Windsurfers are very interesting test vehicles for rigs because you can easily switch from a high lift/high drag rig to a low drag/low lift rig and see how it affects different types of board in different conditions. The differences are enormous.

    I too would be interested in hearing what the FSU wind tunnel guy wanted, and why his expert advice was rejected, given that aerodynamic efficiency is required in a birdwing mast.

  10. #80
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Guys don’t hate me but after giving it more thought, I misspoke with all those statements about “most” of my birdwing masts not really being birdwing masts. Much closer to the truth is that the expression “birdwing mast” actually applies more accurately to all of my prototypes rather than to the design described in U.S. patent #8,739,720.

    In a court of law it would soon be discovered that “birdwing mast” is actually the slang term that the inventor of U.S. patent #8,739,720 has been using to name all of his prototypes of his invention for the last ten years or so. As a matter of fact the term “birdwing mast” is never even mentioned anywhere in the language of U.S. patent #8,739,720. (More about this later)

    In regards to the guy in charge of the wind tunnel at FSU (at the time I wanted to use it), he was most certainly no aerodynamicist. He also most certainly was not a sailor either. He was a mechanical engineer but what he didn’t know about aerodynamics and sailboat mast construction, he more than made up for with arrogance. He thought that a strong central core was the way to go with soft lightweight add-ons to the central core to accommodate aerodynamic concerns. When I told him that was pretty much the opposite of the way sailboat masts were actually made, he started telling me about all his years of training and of course his doctorate degree in mechanical engineering. The funny part was that when I told him that he was not going to be redesigning my mast, he got so mad that he threw me out of his office saying that I did not respect his expertise enough and that was the one thing that he had gotten correct!

    Getting back to the definition of a birdwing mast, what I should have said is that most of my birdwing mast prototypes do not meet the aerodynamic description of a storable sickle-shaped sailboat mast as described in U.S. patent #8,739,20. It is only the last one or two of my prototypes that have utilized an “aerodynamically efficient” cross section along the curved part of their curved sections (and therefore might very well be able to meet the description of the invention found in U.S. patent #8,739,720).

    The point I was trying to make was that if a mast design is to have any chance of patent protection from U.S. patent #8,739,720, it would have to utilize an “aerodynamically efficient” cross section, an aerodynamically favorable, swept-back, over-all sickle shape and the ability to self-rotate to take best advantage of wind direction. So in addition to patent protection, it should also be good aerodynamically. That’s my opinion. I will leave all claims of aerodynamic efficiency to the company or corporation brave enough to test the design (at least virtually) and put it into commercial carbon fiber production. If I find that I can afford computer aerodynamic analysis of my design on my own, I will probably pursue that in the future in order to be able to show some evidence of aerodynamic efficiency.

    Sorry about the confusion, I should have given the subject more thought and chosen my words better.

    This is my latest birdwing mast prototype that I think has an "efficient" enough aerodynamically efficient cross section and could possibly qualify for patent protection under U.S. patent #8,739,720.



    This is the same mast setting sail at this year's 2017 WoodenBoat Show at Mystic Seaport, CT.



    This is the same mast stepped on my present boat in my front yard in St. Augustine, FL.

    Last edited by kenjamin; 08-03-2017 at 09:06 AM.

  11. #81
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    This is an interesting thread, interesting concept. Thanks for sharing, good luck going forward.

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    So far, I understand that Ken’s design simply has to be a cantilever mast, and that tuning of the rig amounts to changing of hoop circumference in order to effect set of sail.
    Sails are flat, rather than battened and camber induced (when compared to sailboard rigs).
    There is no downhaul tension and mast bend being static, cannot be changed without reshaping the material.
    This limitation, along with the cantilever configuration, makes it a difficult proposition for a sailboard rig and puts it at a disadvantage when up against stayed rigs on dinghies, mainly because it will be heavier than a stayed rig.
    The AoA is effected by rotion of the entire rig , unless battens and a camber inducing function can be included, that help to create what I see as a two element wing in concept.

    This last idea may possibly be what Ken has in mind, but so far there has been nothing shown to indicate that camber can be induced by mast rotation.

  13. #83
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Funnily enough Frank Bethwaite's wooden wingmasts, including the one Nikki won the world championship with, were made in the way the FSU guy recommended. Frank found that it was the only way to get a wooden wingmast to have the correct bend characteristics. They were certainly pretty to look at, but as with most monos it was soon decided that they were not worth the compromises.

    Frank once wrote of these wing masts that "the fastest were those which, when supported at the base and over a fulcrum at the hounds (12.25ft) yielded at the tip at a rate of 4.9 to 5lbs per inch fore and aft (F) with a circular arc bend except near the base and 2.8 to 3 lbs per inch sideways (X) with no diamond stays."

    To achieve these bend characteristics, t
    he Bethwaite wooden wing masts had a core of pine with balsa fairings. According to Cherub sailor Jim Champ, (who still owns one of Nikki's old masts) "the structural pine is 30mm wide, 38mm lengthwise at the tip 38 * 48 halfway between hounds and tip 43.5 * 59 hounds 47.5 * 69 diamond spreaders ~47 plus 20mm local reinforcement * 69 at the gooseneck 46.5 * 61 at the foot". That shows the complexity required to get the correct bend for performance and easy handling. A small pic of one such Bethwaite masts can be seen at http://www.devboats.co.uk/sailing/qsjb/history.htm I think the light coloured leading edge is the balsa fairing section. The ones I remember had horizontal slices through the fairing to encourage mast bend.
    These masts were soon abandoned in just about all classes, bar a couple of non-spinnaker types, because wing masts in most monos don't provide the performance advantage that people expect.

    The Eric Sponberg wing masts for round the world racing were similar in concept, with a carbon structural core and fibreglass fore-and-aft fairings to allow bend. So the FSU guy was quite correct in that some wing masts are made as he advised. The Bethwaite and Sponberg masts also show that using a carbon mast track goes against the grain of experience, because the stiffness of the carbon and its location prevents mast bend, and the lack of mast bend is inherently an issue with many wing masts.

    Of course, all of this implies that the mast is over-rotated (a complication in itself) because a wing section that is not over-rotated has no advantage over a conventional mast in terms of lee-side flow; see the top diagram by Tom Speer (Boeing wing designer and America's Cup wingsail designer) here at
    https://www.boatdesign.net/threads/rotating-wing-mast-%E2%80%93-theoretical-discussion.14714/page-5

    Sorry for the formatting.








    Last edited by Chris249; 08-03-2017 at 10:10 PM.

  14. #84
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by Lugalong View Post
    So far, I understand that Ken’s design simply has to be a cantilever mast, and that tuning of the rig amounts to changing of hoop circumference in order to effect set of sail.
    Sails are flat, rather than battened and camber induced (when compared to sailboard rigs).
    There is no downhaul tension and mast bend being static, cannot be changed without reshaping the material.
    This limitation, along with the cantilever configuration, makes it a difficult proposition for a sailboard rig and puts it at a disadvantage when up against stayed rigs on dinghies, mainly because it will be heavier than a stayed rig.
    The AoA is effected by rotion of the entire rig , unless battens and a camber inducing function can be included, that help to create what I see as a two element wing in concept.

    This last idea may possibly be what Ken has in mind, but so far there has been nothing shown to indicate that camber can be induced by mast rotation.
    Lugalong,

    The absence of downhauls for the booms is just an oversight on my part. I will be using them on Muri-Maru, the boat I had rendered in 3D virtual space by Bedard Yacht Design (see Muri-Maru thread also in the design section of this forum). I do use a downhaul on Bernadette, my present birdwinged boat.

    The sails certainly appear flat in the renderings but they will have shape sewn into them just like most all regular Dacron sails. If you want to use mylar sails, you certainly can. Muri-Maru is showing partial battens but if you want to use full battens, just go for it! The sail can be cut as full or as flat as you want. And yes, you should be able to affect the camber with control over the rotation of the mast either with a separate control or just the mainsheet.

    The sail attachment system can be slugs and sail track or hoops. I have noticed that hoops do seem to allow the mast to freely rotate better but a sail track using slugs should offer better efficiency. Hoops on the other hand offer the simplicity of a junk rig in my opinion. (Pull on the main halyard and the sail goes up. Uncleat the main halyard and the sail comes down - all without leaving the helm).

    If you want a higher aspect, higher performance, lighter weight rig on your boat, there’s no law prohibiting you from using stays on a birdwing mast. If you want to retain the automatic wind vane function of the mast, you simply need to attach the stays to the mast where the center of rotation of the mast exits the mast near the masthead about an eighth to a tenth of the way down (depending on the particular birdwing mast to which you are attaching stays). You could even use spreaders too. Why not?
    Keep in mind, however, that a birdwing rig without stays can be depowered completely and instantly from any point of sail with just the mainsheet control.


    A sailing captain pointed out to me just a few months ago that on a birdwing rig it should be possible to bend the mast with just lazy jacks. So please, if you want to bend the mast with stays or lazy jacks, feel free to do so.

    You literally have no limits on how you can use my birdwing mast technology. The only limit you have is your own imagination.

    How does your new-found freedom feel?

  15. #85
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by Chris249 View Post
    Funnily enough Frank Bethwaite's wooden wingmasts, including the one Nikki won the world championship with, were made in the way the FSU guy recommended. Frank found that it was the only way to get a wooden wingmast to have the correct bend characteristics. They were certainly pretty to look at, but as with most monos it was soon decided that they were not worth the compromises.

    Frank once wrote of these wing masts that "the fastest were those which, when supported at the base and over a fulcrum at the hounds (12.25ft) yielded at the tip at a rate of 4.9 to 5lbs per inch fore and aft (F) with a circular arc bend except near the base and 2.8 to 3 lbs per inch sideways (X) with no diamond stays."

    To achieve these bend characteristics, t
    he Bethwaite wooden wing masts had a core of pine with balsa fairings. According to Cherub sailor Jim Champ, (who still owns one of Nikki's old masts) "the structural pine is 30mm wide, 38mm lengthwise at the tip 38 * 48 halfway between hounds and tip 43.5 * 59 hounds 47.5 * 69 diamond spreaders ~47 plus 20mm local reinforcement * 69 at the gooseneck 46.5 * 61 at the foot". That shows the complexity required to get the correct bend for performance and easy handling. A small pic of one such Bethwaite masts can be seen at http://www.devboats.co.uk/sailing/qsjb/history.htm I think the light coloured leading edge is the balsa fairing section. The ones I remember had horizontal slices through the fairing to encourage mast bend.
    These masts were soon abandoned in just about all classes, bar a couple of non-spinnaker types, because wing masts in most monos don't provide the performance advantage that people expect.

    The Eric Sponberg wing masts for round the world racing were similar in concept, with a carbon structural core and fibreglass fore-and-aft fairings to allow bend. So the FSU guy was quite correct in that some wing masts are made as he advised. The Bethwaite and Sponberg masts also show that using a carbon mast track goes against the grain of experience, because the stiffness of the carbon and its location prevents mast bend, and the lack of mast bend is inherently an issue with many wing masts.

    Of course, all of this implies that the mast is over-rotated (a complication in itself) because a wing section that is not over-rotated has no advantage over a conventional mast in terms of lee-side flow; see the top diagram by Tom Speer (Boeing wing designer and America's Cup wingsail designer) here at
    https://www.boatdesign.net/threads/rotating-wing-mast-%E2%80%93-theoretical-discussion.14714/page-5

    Sorry for the formatting.








    Chris,

    As Iíve said before, the birdwing mast rig is not a conventional wing mast rig. It sets soft sail that can easily be hoisted or struck completely and does not utilize any hard surfaces except for the mast itself and the battens. So itís not a wing mast at all, is it?

    My personal experience is that under bare pole, the birdwing mast design can present a very aerodynamically slick, self-rotating, low mass mast that is very quiet at anchor. The main halyard on the birdwing mast is held away from the mast due to the mastís curvature so there is no sound or vibration as the result of any line rattling or vibrating against the side of the mast. So the boat sits at anchor very quietly. Because the mast can be made to rotate on low friction plastic and be surrounded by a plastic bushing where it enters the mast step, and because it is inherently well-balanced due to itís shape, the mast requires very little energy for it to wind vane itself to a position of minimal aerodynamic drag when the wind changes or is kicking around from different directions as a storm approaches. So no misbehaving at anchor and in fact, from my experience, it is unusually quiet.

    This was my experience from camping very near my boat during the 20 to 30 knot winds of the 2016 Texas 200.

    Can we agree that for once and for all, the birdwing mast design is not a true wing mast?

    Can we agree that there is no law in place that restricts any rigger from adding control lines or devices to a birdwing mast rig such as stays, backstays, downhauls, spreaders, lazy jacks or any other control line for the purpose of extracting better performance or better sail handling from the birdwing mast shape?

    Can we also agree that birdwing masts can utilize as little or as much curvature that seems to be or proves to be advantageous to any boat design or application?

    Can we agree that birdwing masts can utilize the most efficient aerodynamic cross sections that money can buy?

    Can we agree that birdwing masts can be a low aspect ratio rig or a high aspect ratio rig or anything in between?

    I would really like to hear your answers to these questions.

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    1- Depends what one calls a "true wing mast"... :-) The chord length appears to be very similar to that of, for example, the Tasar, and the Tasar mast is universally called a wing mast. Tasar, NS14, Finn, F18, F16, Tornado, A Class, ORMA 60, F40 mast also have sails that can be struck or hoisted completely and use no hard surface apart from the mast and battens. The A Class sail, for example, is hoisted so easily they don't even have a halyard - you just push the sail up the luff tube the full 30' height of the mast. The F18 and F16 sails are close to that. So the characteristics you mention are the same as those found on most wingmasts.

    So sure, you invented it you can call it whatever, but most sailors would probably say it's a wingmast.

    2- Sure, anyone can add devices. But when those devices are so critical to the efficiency of a mast it seems that allowing people to add or take off over-rotation, for example, means that any claims about efficiency would become very complicated.

    3- Isn't that an important question? If a mast has a wider chord than a conventional mast then adding curvature when required, to flatten the sail out, becomes problematic. All else being equal, a mast with an aerodynamically efficient section appears to have inherently poorer bend characteristics because of the greater moment of inertia created by the greater chord. Therefore one may not actually be able to utilise the curvature that seems or proves to be advantageous.

    4- Perhaps not, all else being equal. The most efficient aerofoil section normally has a sail that goes down to deck level to create an end-plate effect. That would be difficult to create with a kinked section as in the birdwing mast. And there appears to be no actual advantage in the birdwing configuration as far as aerodynamic cross sections go.

    5- Perhaps.... haven't really thought about it.

    6- Lots of wing masts and similar spars can sit on plastic bushings; two of mine do. Whether they rotate "easily" compared to the birdwing is impossible to answer since "easily" is not defined. The advantage of "balance" appears hard to discern; some designers add area aft of the rotation point because that allows a wing mast or similar spar to rotate more easily. It's a fairly simple issue - to encourage a mast to weathercock one wants to place as much area as possible aft of the axis of rotation, because that increases the lever arm of the force; it's similar to having the tail of a wind generator stuck on an arm rather than straight on top of the pivot. A "balanced mast" as shown in your sketches does not do that, so it's highly unclear why the birdwing would rotate more easily than any other wing mast or similar spar.

    Out of interest, didn't you think it was at all interesting that Frank Bethwaite, a leading name in the field and a man who built many wingmasts, and NA Eric Sponberg both supported what you were told by the FSU engineer about wingmast structural design?
    Last edited by Chris249; 08-04-2017 at 09:17 AM.

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by kenjamin View Post
    You literally have no limits on how you can use my birdwing mast technology. The only limit you have is your own imagination.

    Sorry, can't help it. https://www.youtube.com/watch?v=gN-ZktmjIfE
    "... and the great shroud of the sea rolled on as it rolled five thousand years ago."

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    The concept reminds me of this dutch boat that has been active on the European raid circuit for years and years:



    The rigs are mounted in rotating stainless steel sockets and when pulled out lie under the gunwales to leave the interior clear for rowing.

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by Clarkey View Post
    The concept reminds me of this dutch boat that has been active on the European raid circuit for years and years:



    The rigs are mounted in rotating stainless steel sockets and when pulled out lie under the gunwales to leave the interior clear for rowing.
    When I wrote Iain Oughtred for permission to try my birdwing mast design on his Caledonia Yawl, this is the letter he sent back to me giving me permission to experiment. Youíll notice that he mentions in the letter about the Dutch boat that had a very similar set up. He also included in the letter some copies of pictures of the Dutch boat in operation. He did say that they did have some trouble with busting one of their spars in a raid event. The funny thing about invention and prototypes is that you only learn something if you fail. If you get it right and it works correctly the first time, you havenít learned very much.



    One guy got very upset with me because he thought I had stolen my birdwing design from the Dutch boat but that was not the case. Iainís letter was the first time I had ever heard of their efforts to address the issue of storing masts within the boat. I also thought that my sickle-shaped design utilizing a small straight section at the bottom of the mast to facilitate both stepping the mast and its rotation was a simpler design solution than one needing special hardware.

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by rbgarr View Post
    No apologies necessary. I need to be reminded from time to time to not take myself so seriously. From watching those videos, if I ever try that rocket pack assist for my birdwing bicycle set up, I’ll need to make sure that the seat of my pants doesn’t catch on fire. That not only looked painful but also so embarrassing!

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by Chris249 View Post
    1- Depends what one calls a "true wing mast"... :-) The chord length appears to be very similar to that of, for example, the Tasar, and the Tasar mast is universally called a wing mast. Tasar, NS14, Finn, F18, F16, Tornado, A Class, ORMA 60, F40 mast also have sails that can be struck or hoisted completely and use no hard surface apart from the mast and battens. The A Class sail, for example, is hoisted so easily they don't even have a halyard - you just push the sail up the luff tube the full 30' height of the mast. The F18 and F16 sails are close to that. So the characteristics you mention are the same as those found on most wingmasts.

    So sure, you invented it you can call it whatever, but most sailors would probably say it's a wingmast.

    2- Sure, anyone can add devices. But when those devices are so critical to the efficiency of a mast it seems that allowing people to add or take off over-rotation, for example, means that any claims about efficiency would become very complicated.

    3- Isn't that an important question? If a mast has a wider chord than a conventional mast then adding curvature when required, to flatten the sail out, becomes problematic. All else being equal, a mast with an aerodynamically efficient section appears to have inherently poorer bend characteristics because of the greater moment of inertia created by the greater chord. Therefore one may not actually be able to utilise the curvature that seems or proves to be advantageous.

    4- Perhaps not, all else being equal. The most efficient aerofoil section normally has a sail that goes down to deck level to create an end-plate effect. That would be difficult to create with a kinked section as in the birdwing mast. And there appears to be no actual advantage in the birdwing configuration as far as aerodynamic cross sections go.

    5- Perhaps.... haven't really thought about it.

    6- Lots of wing masts and similar spars can sit on plastic bushings; two of mine do. Whether they rotate "easily" compared to the birdwing is impossible to answer since "easily" is not defined. The advantage of "balance" appears hard to discern; some designers add area aft of the rotation point because that allows a wing mast or similar spar to rotate more easily. It's a fairly simple issue - to encourage a mast to weathercock one wants to place as much area as possible aft of the axis of rotation, because that increases the lever arm of the force; it's similar to having the tail of a wind generator stuck on an arm rather than straight on top of the pivot. A "balanced mast" as shown in your sketches does not do that, so it's highly unclear why the birdwing would rotate more easily than any other wing mast or similar spar.

    Out of interest, didn't you think it was at all interesting that Frank Bethwaite, a leading name in the field and a man who built many wingmasts, and NA Eric Sponberg both supported what you were told by the FSU engineer about wingmast structural design?

    Chris,

    1) Thanks for correcting me about thinking all wing masts have hard surfaces that were impossible to reef and also difficult to turn off at anchor.

    2) I thought the beautiful thing about racing was that the only claiming you had to do was claiming the first prize trophy for being the fastest. Especially in open design racing, you really only have two choices. You can accept the status quo and possibly place in the top ten, or you can innovate and win. Even if something is tried once and failed, doesn’t mean it won’t respond to a little more tweaking and prove to be successful in the end. Try to be a little more optimistic!

    3) In the world of invention, an area that is “problematic” just means it’s a prime area for improvement. Problems are not a good excuse for not achieving better design. Having problems is at the heart of invention. Solving problems is what inventors do.

    4) Again, “difficulty” is a terrible excuse for no progress in the design world. The Wright brothers certainly had difficulty and they almost did give up but chose to reexamine their difficulties, irreverently discard all accepted tables of lift calculations, correct them and then build much better lifting wings for their second large scale glider. If invention was easy, everybody would do it.

    5) Expertise is much easier to pay for than it is to learn.

    6) Chris, you’re just plain wrong about this one. Because the birdwing mast has significant length along the airflow, because it’s so well balanced in it’s rotation and also because it is so efficiently aerodynamically shaped, it simply does not need an arm sticking out the back with a flap attached to it to facilitate response to wind direction. The advantage of better balance is indeed “hard to discern” but in the case of the birdwing mast, it is definitely there and very easy to demonstrate. I’ll try to make you a video of it responding to changing wind direction so you can see for yourself. Thanks for having me realize that needs to be done.

    I do very much appreciate your contributions to the discussion and especially how you straightened me out about the definition of wing masts. In my old books on sailboat design they show wing masts as having hard surfaces.

    I know my optimism about my design can be frustrating and irritating to some, but that’s not a good reason for me to stop trying. In my lifetime, if my crude prototypes do not point to a better way of setting sail even when rendered in carbon fiber and computer optimized with the best aerodynamic data available and with the best carbon fiber construction techniques available, then I will simply try harder.

    In regard to the idea that a strong central core is the way to go for advanced mast design, I just want to point out that just because my prototypes are in wood and appear quite wide especially from the side view, that does not mean they could not get very thin and more “pencil-like” or more “blade-like” when rendered in carbon fiber. Whether it is my design or someone else’s, change is coming and there’s no stopping it.
    Last edited by kenjamin; 08-05-2017 at 09:56 AM.

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    On my bicycle ride two days ago, I sailed past this poor dead fellow on the sidewalk. In retirement I've figured out that if I bring my camera with me, I can bill myself as a nature photographer rather than just a bicycling bum. I also carry my phone as a backup camera but I prefer to shoot with a real camera, not just for the better resolution but also for the much quicker handling. Anyway, the butterfly was already dead and was the centerpiece of a red ant feeding frenzy. I threw my bike into the bushes, took several pictures standing above my subject and then laid down on the sidewalk to get some closer shots.

    By the time I got really close to my subject, I was amazed that all the red ants had split and scurried off seemingly intimidated by my tremendous bulk. Those ants may have tiny little brains but they have some great instincts. I was drawn to the butterfly by its gorgeous wings. It was the color that had first attracted me but since I have become a birdwing brain, I also noticed quickly the curvature of its wings. I could not help but wonder why if a continuous curvature on the leading edge of a wing or sail is such a bad idea, why is it found so frequently in nature?







    Am I the only one that sees a birdwing mast in this last picture?

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Increased leading edge within a shorter span?

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    This point about increased leading edge relative to span might also be more effective when the wings flap.
    Since sailboat wings, masts or sails are generally static, the soaring bird analogy brought up esrlier in the thread might be more appropriate.
    Krenjamin, your suggestion that I am ‘free’ to unleash my imagination and go puting stays on a bent mast, along with higher aspect sail area and spreaders etc… is not helpful.
    Although the freedom thing has never really been a limitation.
    Let me explain that when I mentioned your rig having no downhaul and having flat sails , what I meant was that it was like an un-battened sailboard (which have been called ‘flat’ in contrast to the camber induced battened sails) and that your mast bend was not induced by downhaul tension.

    My experiment with an arc form spar was aimed at replicating the sailboard rig in larger scale and without the downhaul tension either.
    Easy stowing aling a boat’s gunnel was never my intention and in fact the bent spar proved to a problem rather than a convenience when taken out of use.
    By the wy.something I notice on the Dutch boat (shown a few posts back) was that the boom is also curved, probably so in order to stack with the mast when stowed along the gunnel.
    Curved spars are surely convenient only when they stow along a matching curve gunnel?

    Anyway, I made an arc form spar about 26 ft tall, but did not have it cantilevered, which would have increased the weight and cost of the spar without any performance benefit. So that is why I used stays/shrouds as an alternative. However, these were nothing like uppers and lowers, as in conventional rigs, and spraeders were out of the question due to the mast being so far out of column.
    Induced bend with aid of downhaul or tensioned lazy jacks(as you suggest) is/was never considered, and was a primary reason for making it curved in the first place. Just like your spar.

    For the above reason, Chris’ (249) criticism that a sail track would hamper mast bend is not valid.
    Bending a mast like Bethwaite does to flatten his sail does not even come into the picture (in the case of my version and also for your birdwing spar, as I understand it), but I do see chris’ point that slender deformable masts can be better in terms of their low drag high lift contribution to a rig, even if stays and shrouds are a drag contributor to the system.
    Going with the theory of a rotating cantilever mast being of aerodynamic value disregards a raft of consequences.
    That being the main reason I mentioned supporting wires on this thread.
    True, you need to stick with plumb and rotating mast base in order to accommodate the kink in the spar and have an axis of rotation passing through the upper1/10th of the spar. Again, this is something that I consider as being less than an advantage.
    Discussing merits along with demerits of arc form spars is Ok with me if the sort of things said in this post are no taken with offence.
    Last edited by Lugalong; 08-06-2017 at 05:11 PM.

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by kenjamin View Post
    Chris, thanks for showing up for the discussion. I know you have a wealth of experience and knowledge of sailboat racing that certainly could be helpful in the development of my design. It would be great if you could stop by St. Augustine sometime and we could just go sailing on Bernadette and you could see and feel exactly what the birdwing mast may have to offer.

    By far the most difficult aspect of the design to appreciate is the balance. Because it lunges forward before it sweeps aft as it faces the wind direction, even though it has length along the airflow, it has such low mass and is so well balanced, that it takes very little energy to make it face the direction of the wind. It rotates on a plastic piece and is surrounded by a plastic bushing as it emerges from the mast step. That's all the help it needs to freely rotate to face the wind direction under bare pole. Yes, there are moments when the wind direction changes and the birdwing feels the need to adjust itself and does so but the forces involved are so tiny that it certainly does not affect the boat's direction or set of anchor. In that respect it acts much more like a conventional mast than a wing mast.

    The next thing I'd like to point out is there is nobody on this planet who would like to know more about the birdwing mast design than me. At this year's WoodenBoat Show I spent an evening talking very loudly to my friends across the table from me because the restaurant was so loud. The next day, I spent the entire day talking to people about the mast and the boat and by the end of Saturday, my voice was completely gone. I spent all day Sunday sitting under a dining canopy away from the boat so that I would not have to talk to anyone. This turned out to be a blessing in disguise. I had never sat all day long 10' from Bernadette's stern just watching the birdwing mast adjust to changing conditions. You get a perspective of the design that you simply do not get while sailing the boat. It was a very educational day. I occasionally adjusted the mainsheet to keep the boom from extending beyond the gunwales of the boat when I could but sometimes the wind so strong that this was not possible. I had moments when I was looking for the trailer wheel to lift off the ground and everything going over so in effect I spent the entire day sailing the boat from a distance where I could see exactly what was happening. I think, Chris, if you had been there and observing from a similar perspective, you would soon realize that the birdwing mast is definitely not a wing mast but it is not a conventional straight mast either. It is a brand new type of animal. With its self-rotating characteristics, its like it has a mind of its own. Whatever you might say about the birdwing design, There has never been a birdwing mast before now. I'm not saying it is the answer to world peace or anything near that but to me, it is definitely a design direction worth exploring further.

    In listening to people react to the birdwing mast, I hear a lot of "that's cool" and "wow, look at that thing!" but the one I enjoy the most is "I wonder why no one else has not thought about that one before" Ė that one I can answer. Nobody else had a loud, obnoxious, beer-guzzling fishing buddy that forced the creation of a mast that stores along the gunnel and stays completely out of the way of a couple of guys' fishing. The birdwing is one of those strange two-staged inventions that is great for one thing (storage) but may also offer aerodynamic advantages as well. My latest prototype is really the first birdwing mast that begins to explore the aerodynamic issues of setting sail. It took Thomas Edison one hundred tries before he got to Tungsten as a filament material. Bernadette's mast is really the first birdwing mast that I've ever built that even begins to explore the aerodynamic advantages the design may have to offer. At my age, I do not know how many more birdwing prototypes I have in me to offer the design world. In truth, there's nothing I'd like better than to hand the whole thing off to someone more knowledgable and smarter than me and with the means to take the birdwing design to the next level in carbon fiber and see where it goes from there. So far that opportunity has not presented itself so I will keep plugging along with my tiny research budget and continue to entertain myself in my old age.

    can you tell us about the wind bike Ken? looks like it could be a wild ride! how did it work was the bike stable enough in the gusts?

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by kenjamin View Post
    When I wrote Iain Oughtred for permission to try my birdwing mast design on his Caledonia Yawl, this is the letter he sent back to me giving me permission to experiment. Youíll notice that he mentions in the letter about the Dutch boat that had a very similar set up. He also included in the letter some copies of pictures of the Dutch boat in operation. He did say that they did have some trouble with busting one of their spars in a raid event. The funny thing about invention and prototypes is that you only learn something if you fail. If you get it right and it works correctly the first time, you havenít learned very much.



    One guy got very upset with me because he thought I had stolen my birdwing design from the Dutch boat but that was not the case. Iainís letter was the first time I had ever heard of their efforts to address the issue of storing masts within the boat. I also thought that my sickle-shaped design utilizing a small straight section at the bottom of the mast to facilitate both stepping the mast and its rotation was a simpler design solution than one needing special hardware.

    Kenjamin,

    Well that letter is interesting.

    Iain Oughtred sent you the pictures of a Dutch boat with a similar 'birdwing mast' on May 15, 2006 and your initial patent application was filed on Oct 19, 2007. But you state you hadn't heard of it before applying for your patent??? The facts you present don't seem to substantiate that.

    CORRECTION, I see that there is another application with a priority date of November 19, 2006. Still 7 months later than the letter from Iain disclosing what looks like the thing you patented shortly thereafter.

    Did you disclose the Dutch design to the patent office (or the FSU patent attorney), it is legally required to disclose any prior and similar inventions of which you are aware. By the dates of record, you absolutely state you were aware of the Dutch design BEFORE applying for your first application with the patent office.

    Your failure to disclose is grounds for revocation of the patent. I see in your patent they were NOT disclosed.

    And in 2007 the rule was 'first to invent' NOT 'first to disclose'.

    Well this is disappointing as the facts seem to be a bit confused. Do you care to clarify?

    Maybe the last sentence is what happened? Though I don't see how you could discern the hardware used from the photograph you attached. Perhaps you could post the other photographs so we can see the hardware on the Dutch boat and compare it to your patent?

    Interesting side story: a friend of mine designed a unique drive system for a Stirling engine that was built under a NASA grant. During a Stirling engine conference another engineer came by and saw it. Couple of years go by and the other engineer dies and in doing a search discovered he had copied my friend's design exactly and patented it......

    Alan
    https://sites.google.com/site/helium12sofsailboat/

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by Lugalong View Post
    This point about increased leading edge relative to span might also be more effective when the wings flap.
    Since sailboat wings, masts or sails are generally static, the soaring bird analogy brought up esrlier in the thread might be more appropriate.
    Krenjamin, your suggestion that I am ‘free’ to unleash my imagination and go puting stays on a bent mast, along with higher aspect sail area and spreaders etc… is not helpful.
    Although the freedom thing has never really been a limitation.
    Let me explain that when I mentioned your rig having no downhaul and having flat sails , what I meant was that it was like an un-battened sailboard (which have been called ‘flat’ in contrast to the camber induced battened sails) and that your mast bend was not induced by downhaul tension.

    My experiment with an arc form spar was aimed at replicating the sailboard rig in larger scale and without the downhaul tension either.
    Easy stowing aling a boat’s gunnel was never my intention and in fact the bent spar proved to a problem rather than a convenience when taken out of use.
    By the wy.something I notice on the Dutch boat (shown a few posts back) was that the boom is also curved, probably so in order to stack with the mast when stowed along the gunnel.
    Curved spars are surely convenient only when they stow along a matching curve gunnel?

    Anyway, I made an arc form spar about 26 ft tall, but did not have it cantilevered, which would have increased the weight and cost of the spar without any performance benefit. So that is why I used stays/shrouds as an alternative. However, these were nothing like uppers and lowers, as in conventional rigs, and spraeders were out of the question due to the mast being so far out of column.
    Induced bend with aid of downhaul or tensioned lazy jacks(as you suggest) is/was never considered, and was a primary reason for making it curved in the first place. Just like your spar.

    For the above reason, Chris’ (249) criticism that a sail track would hamper mast bend is not valid.
    Bending a mast like Bethwaite does to flatten his sail does not even come into the picture (in the case of my version and also for your birdwing spar, as I understand it), but I do see chris’ point that slender deformable masts can be better in terms of their low drag high lift contribution to a rig, even if stays and shrouds are a drag contributor to the system.
    Going with the theory of a rotating cantilever mast being of aerodynamic value disregards a raft of consequences.
    That being the main reason I mentioned supporting wires on this thread.
    True, you need to stick with plumb and rotating mast base in order to accommodate the kink in the spar and have an axis of rotation passing through the upper1/10th of the spar. Again, this is something that I consider as being less than an advantage.
    Discussing merits along with demerits of arc form spars is Ok with me if the sort of things said in this post are no taken with offence.
    It's very valid in terms of the birdwing mast being used for craft other than simple cruising boats with rigid spars - and exactly why the people who eschew the significant performance advantages of a bendy rig would want the minor aerodynamic advantages of a wing-style mast is an interesting question.

    Spar flex has been used for eons as a method of depowering (and personally I find it far superior to messing around with reefs most of the time) and a large-chord mast with a stiff luff track has inherent issues in that regard. These issues are actually of less relevance in some high-tech high-performance craft that induced bend with downhaul.
    Last edited by Chris249; 08-06-2017 at 11:38 PM.

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by kenjamin View Post
    Chris,

    1) Thanks for correcting me about thinking all wing masts have hard surfaces that were impossible to reef and also difficult to turn off at anchor.

    2) I thought the beautiful thing about racing was that the only claiming you had to do was claiming the first prize trophy for being the fastest. Especially in open design racing, you really only have two choices. You can accept the status quo and possibly place in the top ten, or you can innovate and win. Even if something is tried once and failed, doesn’t mean it won’t respond to a little more tweaking and prove to be successful in the end. Try to be a little more optimistic!

    3) In the world of invention, an area that is “problematic” just means it’s a prime area for improvement. Problems are not a good excuse for not achieving better design. Having problems is at the heart of invention. Solving problems is what inventors do.

    4) Again, “difficulty” is a terrible excuse for no progress in the design world. The Wright brothers certainly had difficulty and they almost did give up but chose to reexamine their difficulties, irreverently discard all accepted tables of lift calculations, correct them and then build much better lifting wings for their second large scale glider. If invention was easy, everybody would do it.

    5) Expertise is much easier to pay for than it is to learn.

    6) Chris, you’re just plain wrong about this one. Because the birdwing mast has significant length along the airflow, because it’s so well balanced in it’s rotation and also because it is so efficiently aerodynamically shaped, it simply does not need an arm sticking out the back with a flap attached to it to facilitate response to wind direction. The advantage of better balance is indeed “hard to discern” but in the case of the birdwing mast, it is definitely there and very easy to demonstrate. I’ll try to make you a video of it responding to changing wind direction so you can see for yourself. Thanks for having me realize that needs to be done.

    I do very much appreciate your contributions to the discussion and especially how you straightened me out about the definition of wing masts. In my old books on sailboat design they show wing masts as having hard surfaces.

    I know my optimism about my design can be frustrating and irritating to some, but that’s not a good reason for me to stop trying. In my lifetime, if my crude prototypes do not point to a better way of setting sail even when rendered in carbon fiber and computer optimized with the best aerodynamic data available and with the best carbon fiber construction techniques available, then I will simply try harder.

    In regard to the idea that a strong central core is the way to go for advanced mast design, I just want to point out that just because my prototypes are in wood and appear quite wide especially from the side view, that does not mean they could not get very thin and more “pencil-like” or more “blade-like” when rendered in carbon fiber. Whether it is my design or someone else’s, change is coming and there’s no stopping it.
    The Wright Brothers started by writing to the Smithsonian and getting all the available information on the area they were exploring. Nothing they did seems to have collided head-on with basic principles of structures. When they did encounter an issue with aerodynamics, they used scientific model tests. Why not follow that model of studying the available knowledge and developing it with basic scientific tests?

    It's not just a case of "being an inventor" and somehow getting around problems and difficulties when such issues are inherent in the design that has been adopted. Yes, you can get around the issues but the point is that there are trade-offs and there's been no evidence given that there is any benefit that is worth the trade-offs in this case. Ironically, one of those trade-offs was the one you rejected when the FSU engineer mentioned it,

    Nor is this a case of being optimistic - it's a case of recognising certain inalienable physical factors. Inventors have been trying to find practical ways to turn base metals into gold and to flap their arms and fly too, and few people would encourage them to keep doing so now that the inalienable physical factors are understood.

    Re 'change is coming and there's no stopping it"; a wing-type mast is hardly a change; it's an old idea.

  29. #99
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by SNAPMAN View Post
    Kenjamin,

    Well that letter is interesting.

    Iain Oughtred sent you the pictures of a Dutch boat with a similar 'birdwing mast' on May 15, 2006 and your initial patent application was filed on Oct 19, 2007. But you state you hadn't heard of it before applying for your patent??? The facts you present don't seem to substantiate that.

    CORRECTION, I see that there is another application with a priority date of November 19, 2006. Still 7 months later than the letter from Iain disclosing what looks like the thing you patented shortly thereafter.

    Did you disclose the Dutch design to the patent office (or the FSU patent attorney), it is legally required to disclose any prior and similar inventions of which you are aware. By the dates of record, you absolutely state you were aware of the Dutch design BEFORE applying for your first application with the patent office.

    Your failure to disclose is grounds for revocation of the patent. I see in your patent they were NOT disclosed.

    And in 2007 the rule was 'first to invent' NOT 'first to disclose'.

    Well this is disappointing as the facts seem to be a bit confused. Do you care to clarify?

    Maybe the last sentence is what happened? Though I don't see how you could discern the hardware used from the photograph you attached. Perhaps you could post the other photographs so we can see the hardware on the Dutch boat and compare it to your patent?

    Interesting side story: a friend of mine designed a unique drive system for a Stirling engine that was built under a NASA grant. During a Stirling engine conference another engineer came by and saw it. Couple of years go by and the other engineer dies and in doing a search discovered he had copied my friend's design exactly and patented it......

    Alan
    https://sites.google.com/site/helium12sofsailboat/
    Knowing that I definitely thought of my birdwing mast design all by myself in the quiet of my garage late one night, I have never been inclined to assign credit for my invention to anyone else but me. The only help I got was the catalyst for the invention, my loud mouthed fishing buddy who complained about the old straight mast and literally drove me to my curved mast design and that was in 2005.

    Secondly, my design is a relatively simple one-piece sickle-shaped design that uses a couple of off-the-shelf sheaves that cost about $20 – much different than the design Iain told me about that used "expensive hardware" and had no apparent "sickle-shape."

    Thirdly, Florida State University was the entity that pursued the patent, not me. If you feel the urge to sue somebody, sue them.
    Last edited by kenjamin; 08-07-2017 at 07:37 AM.

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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by Lugalong View Post
    This point about increased leading edge relative to span might also be more effective when the wings flap.
    Since sailboat wings, masts or sails are generally static, the soaring bird analogy brought up esrlier in the thread might be more appropriate.
    Krenjamin, your suggestion that I am ‘free’ to unleash my imagination and go puting stays on a bent mast, along with higher aspect sail area and spreaders etc… is not helpful.
    Although the freedom thing has never really been a limitation.
    Let me explain that when I mentioned your rig having no downhaul and having flat sails , what I meant was that it was like an un-battened sailboard (which have been called ‘flat’ in contrast to the camber induced battened sails) and that your mast bend was not induced by downhaul tension.

    My experiment with an arc form spar was aimed at replicating the sailboard rig in larger scale and without the downhaul tension either.
    Easy stowing aling a boat’s gunnel was never my intention and in fact the bent spar proved to a problem rather than a convenience when taken out of use.
    By the wy.something I notice on the Dutch boat (shown a few posts back) was that the boom is also curved, probably so in order to stack with the mast when stowed along the gunnel.
    Curved spars are surely convenient only when they stow along a matching curve gunnel?

    Anyway, I made an arc form spar about 26 ft tall, but did not have it cantilevered, which would have increased the weight and cost of the spar without any performance benefit. So that is why I used stays/shrouds as an alternative. However, these were nothing like uppers and lowers, as in conventional rigs, and spraeders were out of the question due to the mast being so far out of column.
    Induced bend with aid of downhaul or tensioned lazy jacks(as you suggest) is/was never considered, and was a primary reason for making it curved in the first place. Just like your spar.

    For the above reason, Chris’ (249) criticism that a sail track would hamper mast bend is not valid.
    Bending a mast like Bethwaite does to flatten his sail does not even come into the picture (in the case of my version and also for your birdwing spar, as I understand it), but I do see chris’ point that slender deformable masts can be better in terms of their low drag high lift contribution to a rig, even if stays and shrouds are a drag contributor to the system.
    Going with the theory of a rotating cantilever mast being of aerodynamic value disregards a raft of consequences.
    That being the main reason I mentioned supporting wires on this thread.
    True, you need to stick with plumb and rotating mast base in order to accommodate the kink in the spar and have an axis of rotation passing through the upper1/10th of the spar. Again, this is something that I consider as being less than an advantage.
    Discussing merits along with demerits of arc form spars is Ok with me if the sort of things said in this post are no taken with offence.
    Hi Lugalong, good to talk with you,

    The following is just my opinions and not claims. I believe the reason a butterfly wing is curved along the leading edge of its wing is at least a three-fold answer. For one thing along a curve there’s longer length for structure per unit of length. That might be what can make a curved edge stronger overall. Another thing that seems to be going on is the curved shape is acting like a progressive spring as the portion closest to the body of the animal is much thicker than the middle part or upper part. This could aid in the flapping action of butterflies as the spar of the wing appears to be stiff where it needs to be and flexible where it needs to be (closer to the end of its wing) and along with the flexing, the curvature might make it easier for the wings to change direction at the bottom of their stroke. And three, it is a creature of flight spending much of its time in the airflow so aerodynamics has got to have something to do with it too. Even butterflies spend some of their time soaring although it’s on a much smaller scale than birds. Butterflies do some gliding even if for only brief moments. The other thing about butterflies is that their wing material is much more like sail area on a sailboat than a bird’s wing. Sure, sailboat sails do not flap in a beneficial way like they do on a butterfly but both sailboats and butterflies manage to get to windward with similar structures – wings that are like sails on a butterfly and sails that are like static wings on a sailboat. It’s all very interesting to me.

    The birdwing mast has a pretty loose definition when you actually look at it. There’s nothing that says the curved part of the spar cannot be very thin and “blade-like” and also utilize very slick aerodynamic cross sections (slicker than you might think possible). There’s nothing that says it must be free standing. There’s nothing that says it could not look very similar to the profile of a 49er rig, for instance. There’s nothing that says a birdwing mast could not rotate in a socket that’s part of the boat and also utilize stays so that it could look more like a 49er rig. If one could hire the right team of experts, there’s no reason they could not come up with a full race version of the birdwing mast. Whether it could have any chance of being faster than the excellent rig of the 49er is a long shot for sure but it’s not necessarily impossible either. It kind of depends on how much testing one can afford, and the quality of the team of experts you hire to optimize the design and of course the expertise of the carbon fiber fabricators who build it.


    Here’s the thing. Birdwing mast is my name for all the prototypes of U.S. patent #8,739,720. They must adhere to the definition of the invention in the patent in order to expect patent protection from the U.S. government but if I, the inventor, find I need to move beyond the scope of the patent in order to improve the design, I can. Then I could either amend the current patent, apply for a new one or just care less about patent protection and just build it, at least that is my understanding of my options. So realize this about the birdwing mast – it is a bit of a moving target when it comes to its design. The patent may or may not come into play in the future but I will always try to improve the performance of the birdwing mast whether the patent proves beneficial or not.

    My present boat, Bernadette, is really the first boat I’ve built where I looked closely at the curvature of the gunwales of the design (Welsford’s Saturday Night Special) on my computer and matched that to the curvature of the mast I was going to build. However, I ended up storing the mast on the outside of the boat rather than on the inside because the mast seemed like it would be getting in the way of my oars while rowing. I could have changed my oarlocks but I had spent a lot of time making them very strong and pretty and in a good position for efficient rowing. So I made a little oak arm that catches the foot of the mast at the stern to facilitate storing the mast on the outside. If a boat manufacturer ever decides to make a birdwinged boat, they could probably do a much better job than I did of matching mast to hull for storage reasons. My old birdwing SCAMP, Gabrielle, was better at quickly storing the mast along the deck of the gunwale but Beradette’s mast has been fine stored on the outside and I have trailered her thousand’s of miles this way and also did quite a lot of motoring with the mast stored on the outside of the boat in the Texas 200. I find my boom stores well with my straight oars so haven’t entertained the idea of a curved boom.



    Lugalong, as far as the weight and cost of the “cantilevered” birdwing mast, are we talking about how the birdwing mast lunges forward before it sweeps aft? Is it the sickle shape that you are referring to? Yes, it will be expensive to build a smooth transition between the curved part and the straight part and I think it is only recently that ideal computer-optimized cross sections can be correctly tapered along the sweeping curve of a birdwing mast. But the fascinating thing for me is nobody knows how good the design can get. Curiosity killed the cat but it could be the thing that eventually perfects the birdwing mast. I know it will be expensive to optimize the design but I do not agree that it has to be heavy. Why do you think it has to be heavy?

    As far as bending the mast to flatten the sails, it may be the case on a birdwing mast where it could be beneficial to bend the mast to make the sails fuller rather than flatter. Again, they’re no rules saying one way or the other. And anyway rules are made to be broken, right?
    Last edited by kenjamin; 08-07-2017 at 09:38 AM.

  31. #101
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by Chris249 View Post
    It's very valid in terms of the birdwing mast being used for craft other than simple cruising boats with rigid spars - and exactly why the people who eschew the significant performance advantages of a bendy rig would want the minor aerodynamic advantages of a wing-style mast is an interesting question.

    Spar flex has been used for eons as a method of depowering (and personally I find it far superior to messing around with reefs most of the time) and a large-chord mast with a stiff luff track has inherent issues in that regard. These issues are actually of less relevance in some high-tech high-performance craft that induced bend with downhaul.
    There are so many options available to the final design of the birdwing mast that "inherent issues" are not a good reason for discarding the design entirely. Solving the difficult "inherent" problems of a design can be the time when real progress is made. I've been accused of being overly optimistic before but it's never stopped me from trying to improve my design and it probably never will.

  32. #102
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Im just looking forward to seeing a monster Pelican sailing with this rig, either in spruce or carbon, i think it will look great. Im am staying out of the technical debate, i have trouble enough with fluid dynamics.....

  33. #103
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by Chris249 View Post
    The Wright Brothers started by writing to the Smithsonian and getting all the available information on the area they were exploring. Nothing they did seems to have collided head-on with basic principles of structures. When they did encounter an issue with aerodynamics, they used scientific model tests. Why not follow that model of studying the available knowledge and developing it with basic scientific tests?

    It's not just a case of "being an inventor" and somehow getting around problems and difficulties when such issues are inherent in the design that has been adopted. Yes, you can get around the issues but the point is that there are trade-offs and there's been no evidence given that there is any benefit that is worth the trade-offs in this case. Ironically, one of those trade-offs was the one you rejected when the FSU engineer mentioned it,

    Nor is this a case of being optimistic - it's a case of recognising certain inalienable physical factors. Inventors have been trying to find practical ways to turn base metals into gold and to flap their arms and fly too, and few people would encourage them to keep doing so now that the inalienable physical factors are understood.

    Re 'change is coming and there's no stopping it"; a wing-type mast is hardly a change; it's an old idea.
    "Why not follow that model of studying the available knowledge and developing it with basic scientific tests?" As I told Lugalong, the answer is simple – TIME! Neither the patent nor I have very much time left to their lifetimes. If I could somehow assemble a great team of experts to take the birdwing mast to the next level in carbon fiber, I could ask plenty of good questions but the answers would have to come from them. Expertise is much easier to pay for than it is to learn. If I found I trusted those who were suggesting a more "pencil-like" or more "blade-like" configuration for the birdwing mast, there's no law saying I can't change my mind and pursue that design direction for the birdwing mast. Since the patent doesn't seem to be making any difference anyway, I am worried less and less about trying to adhere to it's definition of the birdwing mast or more correctly, a "storable sickle-shaped sailboat mast." And besides, there's nothing in the patent that says the design can not be tall and skinny and stayed or short and fat and unstayed or anything in between.

    On another note, just because man or woman has yet to invent a practical design for human powered flight, do you think that is a good reason to stop trying????

  34. #104
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by Daniel Noyes View Post
    can you tell us about the wind bike Ken? looks like it could be a wild ride! how did it work was the bike stable enough in the gusts?
    Daniel,

    Thanks for your interest in my birdwing bicycle. It is very much a design in progress. I built a bowsprit for it but managed to break the bottle cage hardware that I was depending on to secure the bowsprit. The laminated mahogany and spruce "cube" worked well at stepping the mast and not inhibiting the free rotation of the mast. In truth, I have only tried the design once and was scared to death during the first initial flights but soon became comfortable with the somewhat abrupt gybes. Wind gusts were not a problem but some of the gybes put new hair on my chest! At that time the conditions were not very favorable for testing. It was a strong north wind, but the sand was too wet and soft, and I was missing the power of the headsail. I've managed to fix the bottle cage hardware and only need to hem the edges of the headsail to go at the testing again. Ideally, in my area, a good stiff east wind or west wind and a low tide would allow me to broad reach all the way from St. Augustine to Daytona Beach and back. I definitely am not finished exploring the birdwing bike design but it seems like I spend too much time blabbing about birdwing mast design to actually get anything done on it. In the meantime, here's a picture of what it should look like when it's finished.





    Inspiration for the birdwing bicycle:

    Last edited by kenjamin; 08-07-2017 at 09:49 AM.

  35. #105
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    Default Re: Birdwing mast design to benefit from new sail track composite material

    Quote Originally Posted by skaraborgcraft View Post
    Im just looking forward to seeing a monster Pelican sailing with this rig, either in spruce or carbon, i think it will look great. Im am staying out of the technical debate, i have trouble enough with fluid dynamics.....
    Ian, can I have you cloned?

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