Who hasnt noticed that most new airplanes out there today have 'winglets' attaced to the end of the wings? Some older planes are even being equipped with blended winglet technology. The result is less drag, more effiecient airflow,= less fuel burn.

If we subcribe that a sail is a wing, why not put winglets on top of the mast (some winglets extend both directions, up and down such as the A330). Would you not get the same result? Less Drag, more streamlined airflow?

Has this been tried, attempted, or is it nonsence?

Michael

At the speeds sailboats are operating, I think the drag of the winglet would be far larger then the pressure leak it eventually might stop. The added weight that far up would not do much good for pitching and sideways stability either.

Also, sails and wings are not directly comparable. AoA for a sail is at best 25-30degrees whereas a wing has an Aoa of about 1 degree. The aspect ratio is also way off. All due to the constraints of the different environments the two crafts operate in.


Just my opinion..

Michael,

If memory serves me correctly, Dennis Connor's Americas Cup catamaran "Stars and Stripes" (1988 challenge) had a hard wing sail with winglet "tips" at the top of the mastwing. The mastwing was built and tested by Burt Rutan's company, Scaled Composites in Mojave, CA. The mast tips were added to reduce vortex drag after wind tunnel testing.

I'm not sure if the savings in drag from the winglets will be all that advantageous when considering all of the other things on the boat that cause drag. You have all of the standing rigging, the trap wires, some of the running rigging, spin poles and socks (on some boats), the crew, and harware placed on the mast that will interrupt the airfoil shape... Basically and non-streamlined object on the boat.

Unless the "mastlets" give you a substantial increase in lift they really are not worth the expense. I believe the winglets on the airlines do not increase lift, but just reduce drag (and save about 10% in fuel consumption each flight) by reducing the draga for vortex generation as mentioned earlier.

I may be wrong, but I also don't remember seeing winglets on non-swept wing aircraft. This could be due to the fact that most swept wing aircraft are high speed, heavy aircraft who would benefit from the drag reduction.

what about a bouyant winglet- for a masthead bob- and accomplish 2 things at once

John R.

Michael,

Do a search on Winglets here. We talked about this a while back. Someone mentioned that it had been tried, not sure of the results. I believe the discussion was mostly about mast floats.

How winglets work.

http://www.airandspacemagazine.com/ASM/Mag/Index/2001/AS/htww.html

"Winglets" were tried years ago on A class cats. The principle is sound and the reduction in drag due to the reduction in "tip vortex" is very measurable, the problem with a rotating mast is that to have the winglet as part of the mast, when it is rotated in relation to the sail the "plate" that forms the winglet has to be very large to still offer its effects to the sail on both tacks, the head of the sail has to be "squared" off and attached to the winglet plate by something similar to a "radial traveller" so that sail and the winglet form as near as possible a "one piece" tip. An offshoot of this unsuccessful "experiment" with winglets on masts that is being adopted more and more today was the early application of the square head sail. The same problems are not an issue on aircraft wings as both components are a “fixed” one part. The "Americas Cup" "J" class boats used the same principle at the bottom of the sail when they reduced (to advantage) the "vortex" or "equalisation of pressure" around the foot of their mainsail by using the "Park avenue" boom.

Tigerboy,

Here is a Pic of the winged beast with the vortex reducing tips.

So back to another thread dealing with mast floats that improve performance.....perhaps there is a way to add a similar tip to our boats. Seem more practical than a horizontal winglet type.

And what a magnificent beast it truely was.
Where is it kept now?:

Shame it was not the same shape or even anything like the boat that was challenged in.

It did turn the AC in to what it is now, so I suppose it was progress.

Wasnt that the point? Connor & co did not know anything about the boat the kiwis already had buildt in secret, before they challenged, except the length and width (and boy, was the kiwi boat wide!). The kiwis was obviously thinking "outside the box", and to catch up they needed something really spectacular. There was no requirement for a monohull in the challenge, so they looked at the fastest sailing vessels on the planet, foilers, planing skiffs, trimarans etc., but landed on a C-class on steroids as their best option. They did pretty good under the circumstanses, I would say.


Now, I dont think SS had a proper winglet. I would say they had a tapered top on their wing to reduce tip vortex. I understood winglets to be 90degrees or so to the foil, and their primary function to reduce pressure leakage? Secondary, reduce tip vortices?

There were two of them - The first (a soft sailed version) was once owned by Steve Fossett and I believe is still active in the Great Lakes region in the US (Chicago, IL I believe). I think it was up for sale recently. The second went to a rich guy in Mexico who ran into some financial or legal trouble. The boat sat moored in the water for years (with the solid wing rigged). I saw a picture of it about a year ago where several of the wing panels were missing and boat was very neglected and a terrible state of disrepair. Apparently it came up for sale but I don't think anyone took it home.

I am told the soft-sail Stars & Stripes is in Florida, currently owned by somebody in the Tampa/St. Pete area. I have notes about this and the name of the owner in one of my notebooks, but can't find it right now.

There was a video posted somewhere of the soft sail SS blasting trough a fleet of monohulls. It was made by the new crew/owner, so it's definately sailing. I see that there is a copy on thebeachcats.com..
http://www.thebeachcats.com/modules...&file=index&req=getit&lid=49

Linky no worky

The link worked for me...and it was fun to watch! It took some time to download, however.

That rocks! The look on the guys face on the first monohull (28 or 30 footer) was priceless as she rolled through his lee doing probably three times his speed.

So as not to hijack this thread, I posted my remark about winglet shaped mast head floats here.

GARY

Here is a good winglet
GARY