Wing Sails-Masts?

[556Geoff]

Take a look at this site: http://www.trikini.com/Cheapwingsail/cambercontrol.htm I have been researching wingsails for both multis and ice boat clients. Has anyone had experience with these adjustable wingsail rigs on larger boats? Most wingsails are shape dedicated with one or more slotted flaps to get asymmetry. This rig is very smooth shaped, yet shape adjustable for changing conditions. The rig seems to be far less exotic and not proprietary or secretive in nature of construction or shape. The rig can be either free-standing or stayed too. Does anyone have any thoughts on this rig?

[nero]

Looks interesting. I can not get all the pages to load properly. In particular, the page that describes how he get the camber into his wing. Can you post that illustration here?
regards

[556Geoff]

the camber controls: http://www.trikini.com/Cheapwingsail/cambercontrol.htm
How it works page: http://www.trikini.com/Cheapwingsail/HowItWorks.htm

[nero]

Yes it is the ...cambercontrol page picts that will load for me. The text displays correctly. Is there one of the picts that illustrates how the wing works? Can you post the pict here in this thread?

thanks

[556Geoff]

http://www.boatdesign.net/forms/atta...1&d=1194126075
also: http://www.boatdesign.net/forms/atta...1&d=1194126075 I hope this works for you?

[nero]

Thanks for posting the illustrations. This system looks wonderful!

[Pericles]

Nero,

http://boatdesign.net/forums/showthr...ail#post152124

Pericles

[nero]

Pericles

Thanks for the link.

[RatliffFranklin]

Dennis Conner, "Stars & Stripes", 1988. Biggest wing sail to date?

http://www.americascup.com/en/acclop...4926&idRubr=74

[556Geoff]

What I like about this rig is the fluidity, the multiplicity of shapes that can be tried with this rig. What the challenge of this rig is is the number of control lines (#55 for 11 battens) and how to deal with the spagetti of the problem? I'm confident of the rigs abilities to change shapes but I need to come up with a device to facilitate, replicate, and mirror image the shape for tacking to the other tack?

[Petros]

cleaver idea. But if I read this site correctly, you need a separate line from each pair of battens for each direction of tack. This means if you have 8 battens, you will need to adjust 16 lines to control the camber. Not sure if the crew has to uncleat each set of camber control lines for each tack or not, but it seems to me you still need a way of controlling the angle of attack of the rig, and the twist.

I think a junk rig might actually be simpler, and it allow both angle of attack and twist control with one set of controls that do not have to be uncleated with each tack.

One additional observation is that there is a way to control the thickness of the foil section, but I see no advantage. Additional foil thickness only adds drag. On an aircraft a thicker foil means a lighter structure, but that would not happen with this set-up.

[556Geoff]

In lower wind conditions, one might want to use the thicker more powerful foil with the higher drag properties.

[556Geoff]

Also, one might be able to head lower on the wind with a thicker foil section too.

[Petros]

If one has control of the camber and the angle of attack, there is no advantage to a thicker foil. There is never an advantage to increased drag (except to perhaps slow down slightly faster when you want to "put on the brakes").

A thicker foil is more stall resistant and gives you a more gentle stall, which is important on a trainer type aircraft. The sharper leading edge radius of thinner sections cause the sharp stall. But seldom is such a condition life threating in a boat because you are going much slower, presuming you are paying attention to your sail position, there is little reason that this should happen at all.

There is no advantage to more drag on your sail in a sail boat.

[Squidly-Diddly]

foldable/retractable and stowable GIANT batwings for use on large ships(container, oil tanker?).

They were modeled on, well, a bat's wing. He had concept pics with about four in line on a ship. They would fold down into container pods when not in use.

He also made small 'proof of concept' bats wings he put on a kayak and small catamaran.

I think his main idea was that the Batwing/Sail could be easily folded and stowed into a smaller space than any other mast/sail configuration. They would also be easily reef-able.

I haven't been able to find it again online. I can't remember if he published 'the basics' that would allow others to experiment with the concept.