DIY Wing Sail

Thought people might find this of interest.
A DIY, fully configurable, polytarp wing sail.
Old memories of this web-site were stirred by a posting in another forum.

http://windmek.ca/wingsail/index.html

This bloke has been refining his design for several years - now up to revision 6.
Thought about knocking one up for Teal at about revision 2 but felt the batten
construction at that stage was beyond me :C (cast your own variable-flex in
epoxy & glass rovings) This latest version of batten looks eminently do-able.

It is a complex beast, but dirt-cheap for what it theoretically might do (thrash the
pants off a Storer OzPDR !!) :U
cheers
AJ

Ya just gotta love it when some one uses "back yard" materials with a little modern technology.......... It's a good read and makes you think which is a good thing.

Should raise a few comments from around the traps

Looks like fun ... don't know about efficiency though. He needs another boat with the conventional rig to find that out.

I remember the struggle that the C-class cats had with getting wingsails to perform better than conventional sails .. or even consistently. Was a real struggle through the '70s and '80s

MIK

I remember some of those boats. Miss Nylex & others.
Got a vague recollection that their wing sections were not as configurable as this one.
Pretty much fixed thickness wings or wing masts, & without the ability to vary both
convexity & concavity of their surfaces on demand. But I was a distant viewer so
could have easily not noticed some important details.

Practically, while it would be an interesting exercise to make & use one of these
things in serious competition, I am fundmentally a lazy sod & not competing. :U
A Storer tweaked lug is as much work as I now care to put into my sailing.
cheers
AJ

Many have fooled with this idea over the years. The most famous one was the inventor B. Ljungstrom and these double thickness sails are usually called Ljungstrom rigged.

The marriage of a semi rigid foil with the Ljungstrom is interesting, but I feel it's overly complex.

I've been toying with a new idea for a semi rigid leading edge which also uses vortice generators to help improve flow.

I'll probably build one this summer or fall. It uses a conventional sail, but the mast is fitted with a foil, with attaches to the luff of the sail. The idea was the ability to retro fit current free standing rigs with an adjustable foil shaped leading edge which eliminate the "mast shadow", but more importantly permits a "slat" of sorts that dramatically increases lift.

Basically it's a set of foil shaped hoops that are fitted inside pockets, sewn to sail fabric, much like a batten would be. The hoops are hinged at the front making replacement an easy thing. The hoops are spaced the same as the cringles on the luff and their trailing edge has an eye to receive the luff cringle.

When hoisted the fabric pulls taunt from the halyard and the hoops cause a scallop shaped leading edge. It's looks like it would be a bad thing, but these are the vortice generators. Blue whales have similar bumps along the leading edges of their flippers and they're the most maneuverable of all the whales. Recent tests have shown these very bumps are the reason their flippers are superior to other whales. Since I've played with this type of thing before, I figured I give it another crack.

The advantages are huge with my setup. The sail can be reefed or doused, flaking neatly on a boom. Any free standing rig can employ it. It can be retro fitted to a conventional sail. It doesn't require "panel" layouts like a regular sail does. It can generate about 20% more lift then a conventional sail. It can operate at lower angles of incidence. Going down wind the foil can be cranked around to act as an end plate improving drive.

I should also add I'm using a full length top batten, but the rest are full length pneumatic battens. This saves weight and is very easy to adjust for different wind strengths which solid battens can't do. The total weight is about the same as a conventional sail, because the sail track is eliminated and the hoops are fairly dainty.

The only additional lines are a continuous loop to rotate the mast and it'll probably need two halyards to hoist the sail without the hoops binding on the way up.

My test bed will be an old Catalina mainsail which is about 95 sq. ft. I have a good idea how my test bed preforms with this sail, conventionally rigged, so comparisons will be obvious.

PAR
Mm.....sounds very interesting, patent pending?

I'm having trouble visualising the way the luff is attached I think the sail would be set further aft along the boom so that the luff is say about 6 inches away from the mast. Guessing similiar to a windsurfer sleeve set up with the hoops maintaining the foil shape.

Look forward to seeing the proto

AJ
To me the wing falls down when sailing on a 3/4 reach through to running when the drive from the foil shape is lost and square feet comes into play. I figure it's a bit like engines "there is no substitute for cubic inches". Yes hull speed moves apparent wind forward which works on planing hulls but not much good for displacement.

Mind you an Aerodynamacist I'm not :rolleyes:

Mike

Mike, if the hull is slippery enough and offers enough power, you can sail upwind even when on a broad reach.

The double skin sails have issues, but it's a novel concept if it can be made to work.

Yep, the boom need an extension, but not as you'd think. Rather then add a piece to the outboard end, the gooseneck is moved outboard on a "stand off" attached to the mast. This permits the conventional portion of the sail to set independently of the luff foil. I worked up a mechanical vang (think big ass turnbuckle with a wheel attached to the body) that will act as a topping lift and a vang. I've used this setup on conventional boats and had my racer arranged this way until they banned it (everyone has to use a tackle vang).

You can run a masthead jib and a fixed backstay(s), but no spreaders.

I've looked into a patent, but quickly found a bunch of similar ideas, which all will need to be researched, etc. creating an economical environment that wouldn't be healthy for a new patent. I could just apply, then keep getting extensions to the application to have some protection, but frankly I can't defend a determined builders attempts to use it.

Quote:

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Originally Posted by b.o.a.t.

Old memories of this web-site were stirred by a posting in another forum.
http://windmek.ca/wingsail/index.html
cheers
AJ

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AJ,
I've been trying to contact the designer/builder at windmek.ca - does anyone have an email contact for him???
Thanks,
TomH

did you see the email address on this page?
http://windmek.ca/wingsail/DownLoad.htm

Quote:

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Originally Posted by Boatmik

did you see the email address on this page?
http://windmek.ca/wingsail/DownLoad.htm

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Boatmik, thanks for that!
Nor had I found the 'download' page - nice.
Looks like I have the honor of borrowing your "deeply flawed human" tag for that one.
TomH

Yes, Thanks indeed to Boatnik, who may prove to have only minor flaws :^).

Re Whale flippers, is it not the Humpback that has bumps along the leading edge of its flippers, not the blue?

Re C Class cat wings, There was an Italian entry called Signor G IIRC, and it had a one piece wing which had a complex series of tackles inside the wing form ribs which permitted the camber to be modified, and the side changed, by crew action during the races. However it was beaten in every race IIRC by the two or three section slotted wing of its opponent, and i don't recall who that opponent was, but I was surprised at the defeat because the Italian wing looked more like a wing should.

Howdy Catman,

Yap ... bumps work on a humpback which is waving its fins through the water at low speeds. If my centreboard acts like that, I will have to go out and get a new one :D

You are exactly right about the C-class wings, there have been a number of "more ideal" looking systems that have been completely trounced by something that looks more "agricultural".

However it usually comes down to three things.
1/ weight - lightness is everything - in almost every case it is the lightest wing with the best control that wins
2/ low friction. There was a little article somewhere about how the most recent OZ Little America's cupper had wing problems because of friction and weight from 200 blocks inside the mast needed to control the six or nine elements. They cut it down to 80 with good design. Purpose of the blocks is to be able to dial in repeatable sail settings.
3/ debugging - almost professional teams doing really careful comparison sailing to work out how to set the wings up. eg, broad reach in 17 knots of breeze, set twist of main elements, relative angles and distances of the subelements, also the feedback loop that improves #1 and #2.

Australia dominated for a long time because of these achieved with relatively simple and cheap materials. But then the US Cogito team did the same using a high tech and high expense route.

MIK

MIK

To Boatmik. Good day Sir, said he displaying his Pom upbringing and Hi Boatmik from the last 50 years living in Canada. Seems to me that most of the fun went out of the C Class about the time that the Una Wings started to dominate. There used to be a fleet of simple C Class cats racing out of Vancouver but they seemed to fade away as old soldiers are said to do. I was gven the platform for one plus a mast Blank several years ago and, having just tearfully parted with my wing masted Tennant Turissimo 10+, am now addressing the issue of making this C Class more comfortable to sail for an old geezer as a day sailer. "How are the mighty fallen, they were swifter than eagles etc."

I suppose they were so much more trouble to trailer and assemble than say Tornados, without much more speed, and a lot more trouble than any of the 18 foot jobs being produced in quantity in the US. Plus of course the run of the mill sloop rigged C Class cats could not even pretend to be like the C Class jobs involved in top level and International competition. Perhaps not all of the owners had patient wives either:^)

Howdy,

I quite agree. But actually the big una wing masts were fun too while it was all at a (somewhat sophisticated) backyard level ... which is what the Oz boats were like for the two decades they were dominant.

Beautifully light ply hulls, ply wing mast with a little bit of carbon and foam. All stuff that any of us could whip up if we owned 500 g-clamps! Theoretically anyhow.

But now has moved away from that.

Probably a sensible response as it was only possible for a decent challenger to come together from time to time. Most challengers were pretty crappy and unreliable and had big losses to most of the holders of the Little America's cup. Except of course the years the challengers were able to take the cup home with them!

During the early 70s, when I was starting out sailing, Helios, designed by Lock Crowther and bankrolled by the SUN newspaper and John Haines was sailing off one of our local beaches in Pittwater. They went too high with the wing rig apparently and had trouble controlling the power.

But amazing to this then 14 year old.

MIK

G'Day Boatmik. Two answers in one. About fillets and tape. I was unaware of the work done by your local university on the appropriate range of sizes for fillets on various thicknesses of plywood. The standard approach here tends to be fillet and tape the interior angles and tape the outside corners. Perhaps we/they ( they being the US types) tend to be a bit more concerned with fail proof joints and less concerned about the cost of the epoxy and glass than the more prudent types down under.

Re the una rigs, Yes I know about building wing masts with ply and carbon, I built the 50 footer on my Turissimo ( we have lighter winds here than there). I would be thinking of making one for this C Class if an aluminum mast blank had not come with it.

Cheers Catman.

Hey Catman,

Regarding fillet and tape in the other thread ... no such thing as a fail safe join. Where it is reliably as strong as the plywood ... it is enough and no need to go any further. We used to make up boxes of fillet samples for people to break at boatshows about 15 years ago when it was all a bit new.

They would say "impossible". We would hand them a sample and say "break it".

Any pics of your C-class? Haven't seen one for a million years! Is it a wooden hull?

Any chance of sticking a flash camera into the interior and taking a few shots of the structure if it is wood?

MIK

Hi Boatmik, Yes, she is wood all right. Built out of door skins, which as you know do not have waterproof glue between the veneers, so it is imperative to keep them dry.The exterior was covered in glass set in polyester, then painted. They had been stored upside down on their trailer for several years and water had got into the plywood from the edges of the centreboard slots. So the first thing I did was to peel off any veneer that was obviousy lifted off and falling to pieces , run some slow cure epoxy down between the edges of what looked like sound wood that was just coming apart,then replace the missing veneer with a couple or three layers of glass cloth set in epoxy and refaired the whole area with the usual epoxy and glass bubble mix. However I was worried that the interior might also be coming apart, so after I had made some cradles on casters I rolled one into the workshop and cut the deck away around the centreboard slot so I could get a good look at the area and also get at it if any fixing needed doing. It all appears to be sound from that side on the first one I have done that to but I think I shall epoxy some 6mm contour cut divynicell over the area where I had had to make repairs to the outside, backed with a layer of glass cloth, just to ensure that there is adequate stiffness against "oil canning" in that location. Weight is no longer of any concern to me from the speed sailing point of view. So I can send you a picture of one hull upside down on the trailer so you can observe the profile and one or more of the deck, the area cut away and what the inside currently looks like. Do I send these to the list or to your home address?
You will note that the bow is well curved, maximum waterline length was not a priority when it was built. There is a local reason for that. Years ago all the timber that was moved in bulk in this timber producing province was moved by sea in log booms. These sometimes lost a few logs if the weather turned bad, and until they either came ashore at high tide or were picked up by small boats that made a living at it (you may remember a TV show from here called "The Beachcombers") they floated around and were very hazardous to small craft. It helped if ones bow was not plumb but well curved so that it would run up and over one if you saw it too late to avoid. These days the logs are mostly carried in self dumping log barges or ships and the hazard is much less than it was, but to a fast moving lightly built hull they are still bad news. My Turissimo lost two daggerboards to logs that the bow had ridden over, for example, but the heavy reinforcement I had incorporated into the bows coped OK.
Let me know about the pictures.

Wow... the beachcombers was one of my favourites in the '70s

MIK

Filmed in Gibsons, which is where we lived from 74 to 97. The Hero "Nick" in real life considered himself God's gift to both acting and women, wheras the sort of villain "Relic" had been a Shakespearean actor for years and was a very nice person too.It's also where I built the cat, from 82 to 87.

Filleting and taping (if required) on the inside of a corner (a chine for example) and radiusing and taping the outside is standard here in the USA.

I think what happens, as Michael has pointed out in previous postings, is some designers aren't engineering the structures, but rather making them "strong enough" or in other words, overly heavy, epoxy laden and over use of fabrics. I'm at the age where most of my contemporaries are actually engineering structures, but a fair percentage of my generation (say 40%) and most of the previous generations of designers, are using "rules of thumb" developed in the 60's and 70's. This was before we knew as much about the actual strength and bond qualities of the materials and techniques we employ in our structures currently. Hell, it was a half a century ago, we were guessing.

An example of modern, light taped seam construction is one I just did for a Canadian client.

It's a 10' long, 4' 3" beam, single chine uni rigged sailboat. The bottom and sides are 1/4" plywood, the chine is filleted and taped inside, and only taped outside. There is a short keel batten under the mast, back to the daggerboard case. There is a sheer clamp (I think you'd call this an inwale), two 1/4" plywood bulkheads (filleted both sides, taped one side), one forward, one aft, forming air chambers, a centered thwart which lands on the trailing edge of the daggerboard case and a single stringer about midway up the sides of the boat in the cockpit area, plus a small foredeck also in 1/4" plywood. Two longitudinal stringers capture the plywood partner at the mast and that's it for the structure. There is a keel rub strip and a sheer rub rail, but they aren't structural. The boat has about 45 sq. ft. of sail on a Bermudian sprit boomed 2:1 aspect sail and weighs about 65 - 70 pounds full up. There are a few fasteners, but most are rig attachment points or removable pieces, like the rub strips. Everything else is glued, with a some things requiring fillets and some fillets and tape (only the chines and the inside of the bulkheads are taped). This is classic taped seam construction with an eye on weight, ease and speed of build.


I still see taped seam builds with intermediate frames, floors, keels, etc. If structural analyses was preformed, the need for these pieces would be realized (and eliminated), but old coots die hard and I don't think it's necessarily indigenous to Americans. I've seen plenty of "off shore" designers using these "old school" methods, many of whom have fine reputations. Most people, designers included, "stick with what they know". The wise professional tries to keep current with material physical property developments and additions. In other words, I'm sure L. F. Herreshoff would have cussed at free standing carbon spars, but he would have eventually read up and studied the material and likely have changed his mind. I know I've head to reset my mind set on many methods and materials over the years, so maybe I'm getting to be an old coot too.

Howdy PAR,

The university tests showed the optimum fillet had a radius of 2.3 times the ply thickness plus or minus a little.

My rule of thumb for that is I always specify 3 times the ply thickness. But if the angle is too obtuse for the epoxy to form a good fillet I will move over to glass or a flat backed fillet rather than a radiussed one.

Like in this Eureka - the epoxy under the glass tape for the topside join (the bottom panel join is at a good angle for a fillet alone) is purely so there is a more or less smooth ride over the copper stitches. So a real amalgam of methods ... keeping the ugly and time consuming one up in the ends of the boat.

http://farm3.static.flickr.com/2058/...33ff8993b7.jpg

Timber works much along the same line too ... so bonding surface has to be about 3 times the thinner of the ply thicknesses in the joint.

MIK