Understanding Wing Technology

UWT- Offer from Steve Clark-wing plans!

From SA:

Suppose I designed a "basic" wing that could be built out of non exotic materials. In other words slightly more advanced than home depot stuff, but not a whole lot. I would try to keep the BOM cost as low as possible. It won't be absolutely the lightest thing, but won't be gross either. It won't be the latest thinking, but it will work and will perform better than the softy rig it would replace. In terms of rehabilitating old small
I would size it at about 11.5 m^2 ( 125 ft^2) which would be just about right for a single handed small beach cat or Weta. Would people be willing to pay (say $300) for plans??
I'm not going to get rich doing it, but think there ought to be some compensation for the knowledge transfer.SHC

Beatings will continue until morale improves.

 

Doug, if you hit control ++ in Photoshop, it is very easy to read the Miss Nylex files.

 

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Thanks ,Gary but I don't have photoshop. I'm hoping someone could put them into a pdf format. Thanks to your post on SA I've already read the article-would just like to save it.

 

pdf's

 

pdf

Geez, thanks Gary! I really appreciate it, man.....

 

more pdf's

 

Kite speed runs are at deep wind angles.

 

UWT-building Canaans wing/Moth wing(?)

From SA-Fredo on building:

Confirming Steve's estimate, we used one layer of 200 g/m^2 carbon cloth on either side of a 1/4" inch nomex core. We increased the core thickness to 3/8" on our current ribs in an effort to stiffen the ribs, which were bending under the compressive loads of the shrink wrap. We have been happy with that change. In our 1/4" cored rib wings we used carbon arrow shafts as a retrofit glued to the top surface of the ribs to reduce the ribs bending. They worked well and were relatively inexpensive. The Cogito wing used arrow shafts as the primary rib material in its upper wing. Cannan used arrow shafts to form the sides of its ribs to stiffen and save the wing covering from rips due to sharp rib egdes.

We build our ribs in Steve's method, by building big sheets of rib material (vac bagged 200,nomex,200) on flat table, then we water jet cut the ribs from the flat stock. Hand cutting would work fine also, but we had the files and the budget, and we needed lots of ribs, so the water jet saved us time. There is no reason for most builders to use nomex. We were working with it anyway and were willing to pay for weight savings. Except in wildly enthusiastic efforts, foam would be easier and at least as good.

Good luck.
Fredo

 

UWT-more from Steve Clark

From Multihulls on SA:

Tech check:
Can someone take the weights of a Hobie 14 rig and a Weta rig. Include mast, boom, sails and all the other stuff that makes the sails work.
The deal is to get an apples to apples comparison of what the existing sailing rig weighs. They are usually heavier than you expect. For example when we weigh an A Class rig we include the traveler because it is necessary to trim the sail.
This wing project, which pretty much tries to use the X Wing level of technology, ends up weighing about 2/3lb/ft^2. Or about 83 lbs for a 125ft^2 wing. This may be too heavy. More modern wings have gotten down to about 1/2 lb /ft^2. That is done by using all the candy in the store.
The D sections are the biggest chunk of weight, and there may be no substitute for molding cored carbon pieces if we hope to keep the weight down. Lighter is always better, but it does come with a cost.SHC

Beatings will continue until morale improves.

 

What were they using - surely this is not the wing described in post #68? 2/3lb/ft^2 is more than the density of 6 mm ply.. It seems awfully heavy. I would expect to be able to match or more likely beat that using all-wood technology, without going for balsa or fabric covering, which I likely would use to build a wingsail. I understand there is still a mast or equivalent inside for it to pivot around but even so ...

 

In Top Speer's article regarding wingmast design. He has used a simple method for designing a wingmast/sail combination, by first selecting a suitable assymetric airfoil shape and then shape the wingmast/sail combination to fit the outside camber of the original airfoil. My question is, in wing sail design do they use a similar method for developing symetrical elements and for calculating the desired camber?

Cheers
Mojo

 

The X wing, weighs 200 lbs. The D section is built as described of 1/16" plywood wrapped around 1/8" bulkheads (on 12" centers ) and 1/8"x 11/16" spruce stringers. The rest is built up out of light wood, aluminum and carbon bits. It has lasted forever and gone into the drink so often in recent years that we aren't surprised when it doesn't break again.
I have not finished the weight study, and I'm not at full speed. ( shoulder surgery last week) So a little tolerance would be appreciated.
SHC

 

That explains it. But I wasn't being intolerant, I was just surprised by the weight. Obviously that has contributed to its longevity, which is not common in wings as I understand.

 

Understanding Wing Technology-Q&A-Steve Clark

From SA:
I try to answer questions. Please understand that while I have been doing this for a long time, I do not have reams of data comparing one wing section with another and confirmation that the on the water performance validates the predictions. We just haven't had the time, money and inclination to work that hard. We are pretty smart and we take what we feel are logical steps, but we simply don't have an "optimal" solution. We have "what we have done" and "what works".

1) What has proven to be the most effective section shape used for the main wing? Is it a standard NACA section? If so, # please?
The current #1 elements have been reverse designed using XFOIL or other proprietary foil design software. This has lead to foil shapes that are blunter than the standard 000 NACA series. Cogito's #1 element is 19% section. So is the X wing. Magnus Clark reduced the thickness of the Canadian wings based on a study he did using XFOIL. He has not shared this with me, but from what
I HAVE seen, I am not convinced that he is right and am not scampering around the change my wing shapes. A NACA 0018 WILL NOT BE A BAD CHOICE. It is close enough, but
increasing the LE radius makes the wings a bit more stall tolerant, you can do this yourself or you can wait and plot out the nose sections on the plans.

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2) Should the rear flap be of the same section shape? If not, which section has proven most effective in that role? Is it a standard NACA section? If so, # please?
The trailing edge flap is not the same section. I have used NACA 630A10 and NACA0009 sections. Tom Spear makes an argument for NACA 0012 sections. There are quite a few practical compromises in the flaps and I think any of these sections is fine. The thinner sections will provide a smooth leeward side at a lower flap angle.

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3) Should the main wing and rear flap be 50/50 area wise? Or should it favor greater area in the main wing? If so, what percentage would be the optimal split?
Current wings are pretty much 60-40 splits. We have the #2 at about 20% of #1 as well. The placement of the pivots along the fore and aft axis of the wing determines the lateral displacement of the flaps at various flap angles. This is a fairly complex compromise.

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4) Is there an accepted method for the control systems? If so, are there articles/drawings/photos on the web detailing the principals and execution there of (links please)?
I have DXF or PDF file of what has become the standard control system. This was invented by Dave Hubbard 490 years ago and developed over 10 wings or so by the Patient Lady Team. I believe thay wings are only as satisfactory as their control systems. This is the only one I can say is dead nuts reliable. Send me PM and I will send you the file. Specify format please.[SEE PATIENT LADY CONTROL SYSTEM PDF in first postDL]

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5) Since rigid wings are more efficient, can the total sail area be reduced to achieve equal or greater performance over a soft sail on all points of sail? If so by what percentage can it be reduced?
In theory, but most of the design work has been done to provide more power for equal area. I actually look at it the othr way: since wings can be so much cleaner and can be depowered more effectively than soft rigs and sails, how much could their area be increased? Can this increase make light sails unnecessary? My current best guess is about 25%.

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5) What is the optimum aspect ratio?
Wings are not subject to the same constraints that sails are. They can be taller and narrower, however the vertical CG of the vessel and thus the stability of the vessel is effected by the rig height. You have the competing values of center of effort height and aspect ratio at play as well, so this is a hard answer to give. C Class wings have been about 40' tall for 300 square feet.

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6) How low can the aspect ratio be pushed before there is an appreciable drop off in performance?.
In catamaran sailing there is a big performance increase associated with flying a hull. So being short doesn't pay until it is blowing pretty hard.

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7) Is there a proven optimum side profile shape?
Some variation of quasi-eliptical. What we have done is some form of taper. It is usually simplified for ease of construction.

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8) What has proven to be the best method of inducing twist into a rigid wing sail? BMW Orical AC tri appear to have 9 seperate adjustable sections on the rear flap, Is there a way to mimic this on a smaller scale and be mechanically controled for twist?
The Oracle wing controls were losely based on the Patient Lady system.[SEE BELOW-DL] PM and get the drawing.
SHC


Beatings will continue until morale improves.

 

from"us772" on SA:

Another question would be were to locate the pivot point for the flap hinge on a two element wing. In practice we have found for our application/landsailing of wings that a pivot point that produces too large of a gap makes the overall wing a bit gutless . To make the gap larger place the pivot point further forward on the main element. To make the gap smaller place the pivot point further back. With my own wind tunnel testing I found the pivot point to be placed at 87.5% of the main wing worked best overall. My flap is 15% thick. A thinner flap section would probable want to pivot a little further back than 87.5%. Tom Spear has more info here - http://www.tspeer.co...ap/S901fa20.htm