Self trimming wing sail

[archerships]

From the maker:

Since the invention of aircraft, a similarity has been noticed between the operation of sails on boats and the function of wings of aircraft. Sails on boats provide thrust in a horizontal direction derived from moving air, and wings on aircraft provide “lift” in a vertical direction to support a plane in the air, also from moving air (relative to the plane).

In order to fly, wings had to have a certain degree of efficiency, and some experimenters have realised now that aircraft-type wings could be used on a boat and would be more efficient than sails.

Having tested wings on boats in place of sails (“wingsails”) designers noticed another feature used on aircraft that would be useful to use in conjunction with wingsails – controlling the wingsail with another smaller surface mounted behind or in front of it (a “tail”).

There are many examples of tails used to control the direction of bodies both in the water and in the air, and aircraft use them to adjust, to a precise degree, the lift or (angle of attack) of their wings.
If a tail is used attached to a boats’ wingsail, it can adjust the wing perfectly to every small change of wing direction, in this way relieving the sailor of this task, which is mostly guesswork and at best very approximate, and it can perform that job much better than any sailor can do.
Such a wingsail/tail combination is referred to as a self-trimming wingsail.

Original: craschworks - comments

Comments

[ernunnos.livejournal.com]

That is beautiful.

Recently, for the first time, a solar powered boat crossed the Atlantic. This boat used photovoltaic cells on its roof to charge batteries, which in turn, drove electric motors with propellers underwater to push it along. The achievement was hailed as a triumph of low-carbon sustainable transport. Whilst this was an interesting technical first, it was by no means the first time craft had crossed the Atlantic without the use of fossil fuels.

Heh.

[reichart.livejournal.com]

That is very cool.

I have discussed such a system many times with friends over the years.
He is controlling this manually, and I would like to see this taken one more step, which is to "set" a direction, and have the boat pick the best path given the current relative wind direction.

This too "might" be able to be made mechanical. Although would require an interest device, since tacking would require the mechanical equivalent of "memory" + "direction"

In other words, if the wind is coming from directly in front of you, then you have to slalom.

http://www.macgregor26.com/how_to_sail/tacking_drawing.gif

But your run length away from 0' heading is an interesting question.

In the case of a boat, where you know you can rarely go in a straight line, the word "direction" is not accurate, rather, you are attempting to reach a single point on a 2D plain.

So you have to know this location, or have a way to set it.

Mechanically, you can do this with gyros, but funny enough, to do this right would be illegal (this would be the same device as used in a missile).

About the best thing I can come up with is a device that would reduce error by keeping track (this is the memory part) of how long it went off 0' and then count it back down to go the other way.

This gets tricky with the wind direction changing.

Now, if you use a GPS, this is EASY. You point to where you want to go, and the boat will get you there no matter how much the wind changes.

Thanks for post. If I ever build a bout, this would be one (of several) technologies I would use. The others include covering the whole top in PV, and using wave power and the water's temp diff with air for a Sterling engine. Also a simple wind generator mounted on top of the mast.

Put a half dozen techs together, and a little ship (10meters) can actually make more power than it needs.

[nasu-dengaku.livejournal.com]

Have you also seen this proposal to retrofit existing container ships with giant kites to dramatically reduce fuel usage?

Control of the kite is completely automated, apparently.

They have a working model running on a real container ship.

http://www.inhabitat.com/2008/01/29/transportation-tuesday-wind-powered-cargo-ship-takes-sail/


I am curious how the wingsail concept scales up to very large ships. Since it's likely impractical to build a 600-foot-long rigid wing with tail, I imagine you'd have to do a "triplane" sort of configuration. I imagine that for a large craft it may actually be easier to have a computer-controlled wing that gets data from wind sensors as opposed to a tail.

[crasch.livejournal.com]

Thanks for the link! I have heard of kiteships:

http://ma.gnolia.com/people/crasch/tags/kites

...but I hadn't seen that link.

There have been several large scale wing powered ships:

http://www.ibiblio.org/hyperwar/NHC/CRS/propulsion.htm

My favorite is the Solar Sailer.