NOTICE

The Proafile forums are now closed.

The forums opened on Nov. 1, 2011, and operated until Aug. 31, 2014. There are 400 topics on all aspects of proa and outrigger canoe design, history, construction and sailing, which remain online as an archive.

Skylark: a Dymaxion Yacht

Avatar
RankRankRankRank

Total Posts: 468

Joined 2011-11-05

PM

The ability to throttle down to zero instead of reefing is intriguing!  The Walker Wing boats allegedly went through some rough weather.  What did they need all of those computers for?  Shouldn’t you just have one (presumably hydraulic) control of the tailplane in place of sheet, halyard, vang, outhaul, downhaul, etc? 

Or is there a lot to playing the tail control?  Is that what the computers were for.

Riding out a storm, the feathered wing might have even lower drag than a stayed rig under bare poles…until a bearing or something else fails.  Presumably, that’s when you fire off the explosive charge in the mast step that jettison’s the wing to save the ship.

Here’s one I’d like to see, Michael:  A proa dinghy with a tailplane wing.  An OJ from a more future than retro retro future.

How big would the wing have to be to compete with the crab claw on OJ?

Avatar
RankRankRankRank

Total Posts: 356

Joined 2011-10-28

PM

I don’t know why Walker Wing Sails needed a computer, except for patents and marketing, since it was supposed to be “the boat of the future”. The whole point of the tailplane is that works automatically without input, a bit like a windvane self-steering system.

Presumably, that’s when you fire off the explosive charge in the mast step that jettison’s the wing to save the ship.

Like jettisoning the warp core. grin

Here’s one I’d like to see, Michael:  A proa dinghy with a tailplane wing.  An OJ from a more future than retro retro future.

Not by me, you won’t! OJ must be transportable and I can’t imagine anything more tedious than stepping and unstepping a wingsail at the boat ramp. Besides, trimming the sails is most of the fun of a daysailer.

[ Edited: 30 December 2013 12:51 PM by Editor ]

Signature

All I want to know is are we coming or are we going?

Avatar
RankRankRankRank

Total Posts: 468

Joined 2011-11-05

PM

Wings are a pain, to be sure.  But one nice thing about a proa is you could flop it on its lee side (on a pivoting trailer) and install the wing horizontally using a dolly.  Then you pivot the boat up and voila, stepped.  That way you don’t have to be fooling with the attachment process with the wing dangling around.

Nowhere near as convenient and transportable as OJ.  But I still think its an interesting thought experiment.

Besides, in my more futuristic future, they are sitting, rigged and ready for me on a big mooring field, bobbing around like ducklings, masts perfectly feathered in the breeze.

You could spend some of your sail trimming energy playing with the pantographing akas that steer upwind, and get weight aft downwind.

Just a thought.

But to your point, not as exciting a thought as OJ.  At that scale its a pretty desirable package.  Simplicity, looks and bravery.

Rank

Total Posts: 18

Joined 2013-07-28

PM

pr1066 - 30 December 2013 01:22 AM

It can’t get caught aback and a sudden gust or change in wind direction has much less effect. The only heeling effect that it has is from its own lift - the component of the lift force that is not driving the hull forward is tending to lift the ama.

hope that helps

Peter

Thanks again Peter, these wing-sails seem to have a lot of advantages.

Editor - 30 December 2013 10:05 AM

The tailplane controlled wing really only comes into it’s own when it is free-standing, with no stays to limit the rotation. On broad reaching or running courses it is possible to sail with the tailplane aiming backwards and still provide safe and efficient forward driving thrust for the boat, with no danger of a gybe. This is the opposite of a C-class cat or America’s Cupper, which must employ stays to keep the wing standing,

Thanks for the links,
and about the soft wing-sails of the AC-72’s; unlike soft wing-sails, hard wing-sails don’t produce camber on the windward side; there must be a disadvantage to the lack of camber, no?

RankRankRank

Total Posts: 83

Joined 2012-12-18

PM

As far as making the wingsail more incident-friendly is concerned, I suspect there are a number of approaches which might help :

1). Control the tailplane with lines which are accessible at the foot of the wing so they can be detached or cut to let the tailplane feather.
2). Have a centring spring to bring the tailplane to mid-travel - possibly mount the tailplane on some kind of flexure hinge which would combine self-centring with a low friction motion.
3). Use redundant bearings (for example a freely-rotating bush between the wingsail and the mast) so that if one surface seizes the wingsail would still rotate freely.
4). Make the wingsail structurally self-supporting with the bearings located at deck and bilge level where they can be checked easily and repaired without climbing a mast.
5). Use bearing materials which are salt-water tolerant.

My $0.05

Signature

Peter (H)
Aptitude + Attitude = Altitude

Avatar
RankRankRankRank

Total Posts: 317

Joined 2011-11-11

PM

red cedar - 31 December 2013 02:55 PM

Thanks for the links,
and about the soft wing-sails of the AC-72’s; unlike soft wing-sails, hard wing-sails don’t produce camber on the windward side; there must be a disadvantage to the lack of camber, no?

There’s a definite downside to having no camber. In higher winds (whether it’s blowing like stink or you’ve got a lot of apparent wind from a fast craft) lift/drag dominates and a symmetrical section will work pretty well. At slower wind speed maximum lift coefficient is much more important and a symmetrical section sucks. Most hard sail craft use either a multiple surface wing with variable camber or some major flap action.

Cheers,
Skip

Rank

Total Posts: 2

Joined 2013-09-09

PM

Well done, Michael!  I really like the concept and what you’ve come up with.  There’s a definite 50s feel to this, too: an era of science and invention, where people like Bucky ran with ideas.

Cheers,
Laurie

Avatar
RankRankRankRank

Total Posts: 224

Joined 2011-11-13

PM

Editor - 30 December 2013 10:05 AM

Material costs wouldn’t be as high as skill costs. It really is like building an airplane wing. Land and ice yachts have been dabbling in wing sails for years.

Hi everyone. As usual Michael, you’ve done a stellar job of stirring people’s imaginations. I love it! Somebody mentioned earlier that this would be a hard-to-build hull shape. I disagree; it has no more curvature than traditional monohull carvel hulls and could actually be a joy to build. If in strip foam, for instance, one could build a 1/4 mold—that would be 1/4 of the boat, not 1/4 scale! and then pull 4 identical hull pieces from it, glue them together and the hull’s done. I’d build the mold as a “female basket” mold as these have no highly polished surfaces—the finish work is done after assembly, hatches, etc. are all in. Ama is the same game, at smaller scale (build the ama first, for practice!)

Not sure how large you spec the Dymaxion boat to be, but Jim Brown is designing and building very robust and inexpensive pantographing trimaran crossbeams on a 24’er—he’s using 2 x 10’s for crossbeams!

[quote author=“Editor”]...youtube video series of wooden wingsail construction: Part 1.

Thanks so much for these videos. I have a strong feeling that wings on boats are going to be a hot R&D space over the next few years. Perhaps here—and now—is as good a place to start as any.  wink

First, in defense of single-piece, non flapped wings and eliminating reefing, please note that http://www.saildrone.com now has more than 6000 open ocean miles on it, and that completely unmanned. Never reefs, never needs to, hasn’t broken yet.

Second, Worsley’s trail boom control. This is not new, but his utter simplicity in making it work is. His system is 100% mechanical—no computer, no electricity, no hydraulics. Everything built of cheap DIY/hardware store parts. The setting mechanism is set and forget, the boat self-steers a compass course with wing self-adjusting forever (as long as the batteries for the rudders don’t go flat!) The tail is the “throttle” and, if set on low speed, will bravely and simply drive the boat—through hurricanes. I recommend reading his website carefully and watching his video—the one showing how the mechanism works—a dozen times. http://www.youtube.com/watch?v=jGo4bRHI22o

Wings. I am of the opinion that hard wings, up to 100-150 sq ft, can be built uber-simply and uber-cheaply of hotwire-cut foam, a bit of strategically inserted wood strips (google “ribbon spars”) and finished off with heavy duty heat-shrink plastic (the kind used to winterize boats)—true “monocoque” construction where the skin takes the forces. The R/C airplane crowd is leading the parade on this technology—google “foamies”.

I’m currently building 5’ and 6’ sections working to optimize and simplify the materials and procedures, then will go to 10’ span and see where it leads. The weight is on the order of 1.5X the lightest carbon-fiber-and-nomex splendor that the AC guys use, and that’s at 20’ span. Cost is negligible; materials are on the order of $5 sq ft of finished wing—half that at experimental/dinghy sizes, 1/4 that for 5’ experimental model wings. These are astonishingly durable if the right foam is used in the right places (can you say “pool noodle”?) simple to repair (packing tape) and cheap enough that if you completely prang one, you’ll salvage the hardware bits and get the spare wing parts out of the back of your car. The technique works with or without flaps on the wings (easier to transport if it comes apart) and once you get finished with the essentially flat learning curve, you can hotwire all the parts for a pretty sizeable wing in an afternoon.

I may even be able to make a case for building hulls of the foam/heat-shrink though I’m not sure just yet. The engineering pencils out but the reinforcements, mast step, foil and ama mounts etc. labor and costs may push the final cost higher than “disposable” warrants. Does anybody here have experience in papier mache tubing for things like crossbeams and stub masts? If you substitute water-based varnish for flour paste, the stuff is completely waterproof. Wonder what would happen if you soaked SonoTubes (for casting concrete piers) in shellac for a week or two?

The tailplane controlled wing really only comes into it’s own when it is free-standing, with no stays to limit the rotation. On broad reaching or running courses it is possible to sail with the tailplane aiming backwards and still provide safe and efficient forward driving thrust for the boat, with no danger of a gybe.

Completely agree.

Dave Culp

Avatar
RankRankRankRank

Total Posts: 356

Joined 2011-10-28

PM

Thanks for the always thought-provoking reply, Dave. Please keep us posted on the foam wing experiments! I agree with you, I think the AC72’s have put wing sails back into business, so to speak. Maybe we can make up for the disaster that was the Walker Wingsail.

First, in defense of single-piece, non flapped wings and eliminating reefing, please note that http://www.saildrone.com now has more than 6000 open ocean miles on it, and that completely unmanned. Never reefs, never needs to, hasn’t broken yet.

Thanks for the saildrone link - there’s good video of the boat charging along half submerged like a mini Dymaxion! Also, good shots of the boat sailing off wind with the wing pointing “backwards” and yet still providing safe, predictable and steady thrust.

Michael

Signature

All I want to know is are we coming or are we going?

Avatar
RankRankRankRank

Total Posts: 224

Joined 2011-11-13

PM

author=“daveculp” date=“1389399544”] Part 1 Thanks so much for these videos. I have a strong feeling that wings on boats are going to be a hot R&D space over the next few years.

Well, I spent an enjoyable hour watching these build videos last night, and while very complete and very instructive, I think I cannot conceive of a more difficult way to get out a heavier—though perfectly shaped—wingsail! The thing is built like a tank, is an astonishing conclave of precision design and layout plus completely-seat-of-pants hand forming (of solid wood!) with hand planes. He doesn’t quote weights, but this ~20’ X ~4’ wing and flap have got to weigh upwards of 100 lbs. This is an outstanding example of state of the art in wing building (circa 1950 or so) and exemplifies precisely what I perceive to be the major holdup for experimenters to give wings a try—they’re heavy, expensive, complicated and deadly…  All three of those attributes need to go—every one!

Dave Culp