Wing-drive

[masrapido]

Admittedly, your sails did not target cruising, judgeing by the pictures on your page. But even with the hobbycat, if you get hit by the gust, can you reduce the sails, furl them or something?

[kjell]

The big difference between sailing with cloth sails and sailing with Wing-Drive in gusty winds is the safety. Everyone who has the experience of what happen with your boat when you don’t trim the sails in time to the gusts wind direction and wind speed. The result is capsizing. Because the sails are attached to the hull, with the sheets and adjusted to the wind before the wind change. The Wing-Drive is free swinging and has no sheets controlling the angle to the wind. The Wedge Tail is doing this automatically. You set the AOA you like to use and the Wing-Drive will mantain the wind at this angle where ever the wind is coming from. The strong wind gust is converted in acceleration and not to heeling the boat. When the Wedge Tail is set to Zero the wings actuate as a wind vane and there are no needs to reduce or furl them. The wind resistance of the wings in Zero position is less then a normal rig without sails. This has been verified in wind tunnel tests.

[CT 249]

If the Wingsail was so effective, why did it perform so badly when Yachting World magazine tested it and (IIRC) in the Weymouth Speed Trials?

I sail on several boats with free-standing rigs; some fully battened, some not. They still have significant wind resistance even when freely rotating. Didn't Loick Caradoc (sp?) from Royale and other sailors die when their big wing masts capsized their boats even when fully feathered?

[kjell]

The biggest difference between Wingsails and Wing-Drive is the safety factor. Wingsails are often made very big to be able to make speed records. Wing-Drive is different. It is not made to be faster than sails, but safety and easy to operate. Free-standing and freely rotating rigs are not the same as a free-swinging Wedge-Tail controlled Wing-Drive, perfect balanced and mounted on ball bearings. Every change in the wind direction is controlled by the Tail not by man power.

[masrapido]

Hi Kjell, I like your idea. To understand it more could you explain how does one stop the boat from sailing when in a marina. And also, if wings are free to move with the wind, how do you keep the direction of the boat when wings turn with the wind to, say 20 degrees to the left? It is good to have some degree of control over the wings just in case things go wrong ways.

Creo que entiendo el concepto pero' me gustaria si me lo clarifique Ud.

Saludos

[masrapido]

And what are the profiles of the wings? Symmetrical shapes or airfoils of some kind? Symmetrical shapes would not have big lift factor to them.

[kjell]

Hola masrapido,
Wing-Drive is a wind propulsion system not a sailing system this difference is difficult to understand by cloth sailors. The only what booth have as power factor is the wind. Operating a control handle, similar to the engine control, the Wedge –Tail gives the order of the AoA the wings has to work with. The control handle has Left-0-Right positions. In the 0 Zero position the Wing-Drive is a wind vane with no thrust. If the wind is coming from your left side looking forward putting the handle to Left the boat will go forward, if putting the handle to Right the boat will move reverse. The course to steer is up to you, you can’t steer direct in to the wind of course. The altering of the course not affects the wing angle to the wing and the wind shifts are automatically adjusted by the Wedge-Tail. Take a look to my web page. If you contact me by my Email, I will send you more information.
http://www.dahlberg-sa.com/kd/index.html
kjell@dahlberg-sa.com
Saludos

[CT 249]

Originally Posted by kjell

The biggest difference between Wingsails and Wing-Drive is the safety factor. Wingsails are often made very big to be able to make speed records. Wing-Drive is different. It is not made to be faster than sails, but safety and easy to operate. Free-standing and freely rotating rigs are not the same as a free-swinging Wedge-Tail controlled Wing-Drive, perfect balanced and mounted on ball bearings. Every change in the wind direction is controlled by the Tail not by man power.

I have sailed with several wingmasts and rotating rigs, and some have been mounted on very free-running systems. I think one guy I knew had ball bearings on his wingmast. Windsurfer rigs are also free-rotating with little friction. Many of these rigs are also free to rotate into the wind, without man power. However, in marinas where they were struck by winds from wildly different angles, these rigs produced power for a very short time while they rotated to neutral. The same thing happens with windsurfer rigs. This power causes enough boat movement to be a significant problem. Does this apply to your rig and if not, why not? Are you sure that the tail will rotate the rig so quickly that it will not cause any significant power to be directed to the boat itself?

What happens if I am moored in a cove with fluky winds? If the rig is free to rotate, what happens if someone is walking past it when a gust hits from another direction? Your plans show that even on a cat, the rig sweeps across the full beam. Doesn't that mean that at no time I can be sure that I can safely walk from bow to stern? Obviously the rig cannot be secured when at anchor.

[rob denney]

Originally Posted by Andy P

The land yacht pic is a fake!

the centre pic is a bit of a joke

the proa pic is an 'artists impression ' !

It is indeed an artists impression, but we started building the wing for a 7.5m proa earlier this year. The boat was to be a prototype for an 18m/60' version. After the engineering was done, and the stub mast completed, the owner decided it was not necessary. We are meant to start work on the full size one as soon as we complete the current 15m/50' harryproa http://www.harryproa.com/building_Vi...s_11Launch.htm The new one will be a wing driven boat, bound for the east coast USA asnd should be sailing middle of next year.

regards,

Rob

[kjell]

Hello CT 249,
The Wing-Drive is designed to not be wider then the beam of the boat. Nobody will bee hurt by the free-swinging rig. There is of course a safety distance between deck and the rig, the same as between deck and the main sail boom. When navigating with Wing-Drive, nobody need to bee working on deck. It is controlled from the cockpit. In strong wind it is much safer because no reefing, no sail to take down .If the boat is running to fast, just reduce the angle of incident. With only 2 degrees is possible to control the boat and not drifting as with bare rig.
As you mentioned (Obviously the rig cannot be secured when at anchor.) only the Zero trust position of the Wedge-Tail has to secured

[CT 249]

Sorry Kjell, but when I am at anchor my boom is not free to swing around 360 degrees and possibly hit anyone within its radius. If it was, the boat would be dangerous. Therefore surely a boom is not a good comparison with the Wing-Drive.

If the rig can swing freely within a radius, then while the boast is moored that area of deck is surely largely useless. Is that not a major problem?

If reducing the angle of incidence always renders a wing mast safe, what happened to Caradec on Royale? That was merely one of several incidents where a boat capsized under only a freely-rotating wing mast.

[kjell]

Hello CT 249,
Your comments are very interesting. I can’t answer the question of what happened on Caradec on Royale. I wonder who controlled the wing. Was the wing fully balanced? Was the angle of incident controlled with a tail or hand operated? A freely-rotating rig is not the same as a free-swinging rig on ball bearings. You can safety walk under the Wing-Drive rig.

[kjell]

I have been asked. What to do with the Wing-Drive when navigating by engine power?
Here is the answer.
Lock the Wedge-Tail in Zero thrust position. As the Wing-Drive is not attached to the boat, it is free-swinging as a wind vane. The boat can be steered in any direction. If the apparent wind is coming in from Port or Starboard side then it is possible to run with wind and engine power together, saving fuel consumption. If the apparent wing is coming in direct from the front, leave the wing in Zero thrust position.

[wingsails]

Hi Kjell, to reply to masrapido the answer is simple. Put the wing in neutral.
A wingsail with a "tail" like Kjells or mine (wingsails.net) will happily weather very strong winds for days and mine has done this. When in neutral the wingsail has only around 10% of the drag of a conventional mast and are much safer up than traditional rigs. My next rig for a small vessel will be hinged slightly different and have a countering spring to take the load when lowering the rig, although at the moment it is lowered with a rope and stay with 2 fingers holding it.
Also there are other builders around. We have built several rigs on 4 different boats from flexible, folding and even ply framed. However so far the symetrical rig seems best for overall use and following Kjells lead with the tail no longer an aerofoil. We did modify the tail to a hybrid of Kjells design and our own and as ever still testing.

[Ari]

Sorry found this thread a bit late..;Had this type of wing drive been tested on any full displacement monohull ?. Any result Kjell ? I'am very keen to know.