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Old 11-11-2013, 08:55   #31
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Re: Remember the Walker Wingsail ?

Congratulations! You just did.
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Old 11-11-2013, 09:02   #32
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Re: Remember the Walker Wingsail ?

What format does this forum accept, I have prepared a word document explaining wingsails. but this is not an accepted format.

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Old 11-11-2013, 09:11   #33
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Re: Remember the Walker Wingsail ?

If it is posted elsewhere, just link it.
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Old 11-11-2013, 09:12   #34
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Re: Remember the Walker Wingsail ?

Control C, then paste it on the quick reply, hit Post Quick Reply.
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Old 11-11-2013, 09:16   #35
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Re: Remember the Walker Wingsail ?

The response I get is invalid File type, it is a word document.I'm lost.

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Old 11-11-2013, 09:21   #36
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Re: Remember the Walker Wingsail ?

I have written a document, a word document explaining Walker Wingsail, the wingsails and Larinka, but you will never read it because this Forum does not accept word documents. This forum considers word documents an invalid file type, and control C does not work.

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Old 11-11-2013, 09:25   #37
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Re: Remember the Walker Wingsail ?

Control C and paste does not work.

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Old 11-11-2013, 09:28   #38
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Re: Remember the Walker Wingsail ?

Quote:
Originally Posted by Wing sailor View Post
I have written a document, a word document explaining Walker Wingsail, the wingsails and Larinka, but you will never read it because this Forum does not accept word documents. This forum considers word documents an invalid file type, and control C does not work.

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It may be our tight spam controls that are the problem. Try again now and see if you can post this doc.

Otherwise, just open the word doc, copy it and paste it here in the thread. If it is a word doc, I can't see why copying and pasting isn't possible. "Control A" then "Control C" to select all and copy and "Control p" to paste it here.
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Old 11-11-2013, 09:32   #39
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Re: Remember the Walker Wingsail ?

Rats! I'm looking forward to it. We've got a Walker Wing Sail on Harbor Island, here in San Diego, as well as a Harbor Wing at the Scripps Institute of Oceanography pier near me in Point Loma.

I wonder if there is something wrong with the website. I've been having difficulty posting pictures this morning. Keep trying!
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Old 11-11-2013, 09:35   #40
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Re: Remember the Walker Wingsail ?

WINGSAILS AND LARINKA
John Walker designed the wingsail as we know it today. His first commercial wingsail was for the Ashington . With no further interest from ship owners he produced the bi-plane wingsailed yacht, Blue Nova, and with requests for a smaller yacht he produced the monoplane wingsailed Zefyr. The demise of Walker Wingsail Systems was not due to any wingsail technical problem. And there are no wingsailed boats in production.
Wingsailed yachts could be produced, Ocean Foil has the wingsail technology. Some multihulls could be “re-engined” with wingsails. The occasional super yacht proposal has shown wingsail type wings, but nothing has happened. There is no technical reason to prevent wingsailed yacht production. Perhaps increasing fuel costs will bring such boats into focus.
Wingsails and sails, a comparison.
Sails have as we know have been around for a few thousand years. Vertical wings have a recent history. A sail is a single surface aerofoil held in place by a mast and in most cases standing rigging. It is usually controlled by running rigging and in the case of larger boats a considerable amount of deck gear.
A wingsail pivots about a vertical axis and in the case of Larinka’s monoplane wingsail is controlled by a tail (aero rudder). The whole configuration is balanced by a weighted boom ahead of the wing. This prevents wing rotation due to boat heel and pitching. There is no additional rigging and deck gear, although the bi-plane wingsail on blue nova did have classic bi-plane diagonal bracing wires.
A sail is controlled by sheets and running rigging like out hauls to affect the shape of the sail, and sheets to obtain the correct sail angle to the apparent wind. Reefing is necessary to reduce area in increasing wind speeds.
Larinka’s wing has two major elements, the leading part and trailing part, there is a small flap pivoting from the leading part. This forms a wing section capable of increased lift (thrust). The leading part can be rotated and the small flap allowed to overlap the trailing part to form a high lift section, (maximum thrust). The leading part can be pivoted to align with the trailing part so that every element is in line, this is the feathered condition, generating minimum thrust with small angles of the tail, or with the tail at zero angle, the zero thrust geometry.
There is an interesting progressive comparison here, if we observe the development of hang gliders. Hang gliders started as single surface wings (sails) and gradually developed to 100% double surface thick wings and lost the rigging. This was done to improve the flying performance, all this on a wing that can be collapsed into a large bag and stored at home.
Sails / Wings performance.
A sail configuration like a main and Jib will have a lift coefficient of about 1.3 a monoplane wingsail with high lift geometry has a lift coefficient of 2.7. These numbers are multiplied by wind speed squared, area and air density to give us the amount of thrust that can be generated. The Larinka wing generates about twice the thrust of a conventional main and jib sail plan. This is a simplified comparison. A conventional sail plan has the most unfortunate aerodynamics, the main attached to a fixed mast is not an efficient aerofoil, try placing a similar object (mast) on the leading edge of an aircraft wing, and I think the pilot would display radical behaviour. The exposed rigging develops aerodynamic drag; these features are detrimental to boats windward performance. The advantage of a conventional sail plan is the ability to dramatically increase the area to get more drive especially off the wind with enormous spinnakers. The other advantage of sails is the extremely light wind performance; here a single surface aerofoil can do well. The disadvantages are the method of control and necessary gear to do this, especially in increasing wind speeds. A hesitant decision to reef can create a difficult situation and even the basic method of sheeting requires frequent attention to optimise performance.
Wingsail Control.
Controlling a wingsail is easy and can be done from a sheltered internal control station. On Larinka the helm has two controls, one for the tail and one for the leading part angle. There is no computer control although that would be easy to install. The two controls are used to tack the wingsail and control the amount of thrust. If the electrics fail there is a manual override method that can be deployed from inside the boat. In all the weather we have experienced on Larinka I never had to put on my weather gear">foul weather gear, I could sit at the helm, on watch, with a cup of tea in a dry environment. We were not subject to the usual fatigue of an external cockpit situation. Without a computer the fail safe mechanism is the concerned watch keeper when conditions become extreme and the boat speeds up, it is normal to reduce thrust. It is still a boat and in several instances we reduced boat speed through some challenging conditions. And this can be done from the internal helm position. Larinka recently experience 50 knots of wind, Joe the skipper reduced the leading part to a zero angle (wing parts in line) and put on just I degree of tail (the aero rudder). Larinka proceeded at 5 knots under complete control, I have been on board in extreme conditions and it is reassuring to have so much control. When all the wing parts are in line the aero drag is much lower than masts and rigging. This is the zero thrust condition; the sail has been put away.
The Ashington and blue Nova had computer controlled wingsails and blue Nova did have a manual system if the computer system failed.
The only limit on a wingsail is the fixed area and this does become apparent in extremely light winds.
Durability and Maitainence.
So far Larinka’s wingsail has proved to be durable. It has had ten years of use and the only minor damage has occurred when the wingsail has been craned off the boat. This was done to allow boat maintenance in a sheltered environment. Wing maintenance is easier than boat maitainence. in ten years of use how often are sails, rigging and the usual gear replaced. I do not have the numbers but I believe it is quite frequent. In a similar way the weight of a wingsail is not a great concern compared to the weight of a conventional rig. Larinka’s wingsail weighs about 1 tonne. And most of this weight is close to the base of the wing. The weight of a conventional rig should include every item required, like all the sails and all the deck gear. That analysis would be interesting.


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Old 11-11-2013, 09:43   #41
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Re: Remember the Walker Wingsail ?

Interesting. Thank you. I've never actually seen either of my two local wing sail boats underway here in San Diego. I have, of course, seen ORACLE, both the tri, the 45 foot and 72 foot cats. And, we can't forget seeing Dennis Conner tip STARS AND STRIPES over in front of our yacht club after his win.
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Old 11-11-2013, 09:49   #42
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Re: Remember the Walker Wingsail ?

I can see how a wing-sail can help when going upwind because of the lift generated (I understand aero-wings because I was a solo pilot for many years), but I cannot see how it would work going downwind.

What I do not like about it is the level of technology needed to run it. A standard sailboat can still work even if every bit of electronic wizardry packs up or fails. In general, I prefer simplicity over complexity.

The wingsail looks like a solution in search of a problem....
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Old 11-11-2013, 09:54   #43
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Mass up high is going to be problem in big seas because of increased pitching moment. No amount of computer control can alleviate that.

Alas, I don't think the performance gains will ever be enough to replace cloth sails.
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Old 11-11-2013, 09:59   #44
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Re: Remember the Walker Wingsail ?

Down wind is like a plane in landing configuration, flaps deployed for maximum lift and reduced stall speed. For Larinka the wing was put into maximum high lift configuration with maximum rudder angle, simple.The level of technology is not scary but I recognize the reluctance to rely on electrickery. There is a manual system as back up.I think the same thoughts about dependence on GPS and AIS.
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Old 11-11-2013, 10:18   #45
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Re: Remember the Walker Wingsail ?

Adelie,
We did experience some big seas, we had just cleared the Atlantic side of the Bay of Biscay and level with the North Spanish coast/ Portugees coast. The wind built to force 6,7,8, and then the numbers didn't mean much. the seas where scary and we got into Figueira Da Foz. We were at one time airborne as we came of a wave and when we had to turn across the wave system, the wingsail became an effective steadying sail. I think you all have probably experienced the conditions when the horizon in front is the top of a wave and the horizon behind is the top of the other wave. Yes I still sail and enjoy almost conventional rigs. I design and build my own small boats, and typically build unstayed rotating masts for single surface sails. I have also experimented with a double surface sail or "soft wing".Wings and sails both have their advantages and disadvantages, I like to think it expands the wind power methods available.
Attempts have been made to float a few houses in England, or was that the winter floods.
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