The nice thing about the internet is that if you live long enough stuff will all come round again.

That is certainly true when it comes to soft wingsails which is something I have been reading up on for many years.

In fact I have seen designs with endplates at the top, and, supposedly even more efficient wingtip feathers a la eagle.

I would say that right now the folks at the leading edge of what is available and has been tested to be superior are these guys:

http://www.advancedwingsystems.com

A number of folk queried the non elliptical shape of their leading edge but they had the answers.

The thing they appear to have really nailed is twist. And attached flow of course.

Its sad that it has shrouds (probably not compulsory, but they keep the chord thinkness small which Tom Speer says is a Good Thing)

There was a similar twin skin rig done by some guy in Scotland. Boat was a piece of sculpture. Looked like a viking boat. sailed for 3 or 4 days and then burned to the waterline. He was going to rebuild but I lost track of it then. The photos looked pretty good, and with sails if it looks good it usually is. Sadly Tystie is not very pretty to my eye:
http://www.junkrigassociation.org/resources/SiteAlbums/781899/DSC03642.JPG
but thats a matter of execution rather than design.


If you were after something a bit more agricultural (and lets face it agricultural is more of a proa feel) then a guy called Tim Dunn came up with a fairly usable soft wing sail design. He used to have a website but this image is all I could find after a very quick look:
http://www.cachalote.org/GB-ship.html
(taken straight from his former website).
The rig is sort of a “modern junk rig” . It has a twin skin leading edge with hinged battens just aft of the masts.
So you sort of had a teardrop around a round mast done in cloth with a single skin sail hanging off the trailing edge of the teardrop.
He was using a Clark Y section developed as per here:
http://www.tspeer.com/Wingmasts/teardropPaper.pdf

Not a million miles from the likes of Tystie et. al.
There is no reason this rig could not get twist sorted out (each batten has a sheet after all) and it hangs off a fixed mast.
One day I really _will_ try this, as I think it has potential, especially if you could keep the chord as thin as possible.


The Omer type rigs were bagged out by Tom Speer and are fairly mechanically complex anyway.
>From (often faulty) memory the issue was chord thickness.
 I am convinced that the answer is less complex.

The solid “balanced” rigs (i.e. with tailplanes) have not had much joy to date. The Walker wingsail thing was a debacle. Several debacles actually. For a lot of reasons I won;t mention. Google the history and you will see why I wont mention them. They certainly suffer from the amusing effects of rolling as per Rick’s comments. And more than a little weight. It was claimed it salied through a hurricane but how close do the eye do you have to be to claim you were in it ? I dont know. The Harbour Wingsail looks nice and seems most developed. I am wary of projects funded by government money though.

Nah, I think the best concept was the NeuralFuzz guy. Even Rob liked it:
https://au.groups.yahoo.com/neo/groups/harryproa/conversations/messages/1356
Sadly he disappeared. He had working prototypes. it had everything including twist control, balance and the ability to over-rotate the nose as required.

If I was looking for a concept to develop then I reckon that would be it.

Second prize would go to a thin carbon foil rotating round a structural round section with a regular trailing edge bolt rope track. That could be made to twist just right with a little experimentation.

Well unless Rob comes up with some kite magic some time soon.


Good luck

Gary