Just thought I’d throw in a comment… We tried a wing sail (50/50 rigid wing and soft sail) on a 10 Rater back in the early 80’s… The extra weight aloft did horrible things to the righting moment and we never achieved anything like the performance of a soft sail… I’ve done a lot with R/C sailplanes over the years (so I have lots of rigid wing experience) and a huge amount of reading about wing-sails… plus I’ve made hundreds (maybe thousands) of very successful soft sails for R/C yachts… In addition, I’ve pretty much an expert in light yet strong construction (from both the sailplane and yacht design and construction I have done)… From what I can glean, soft sails can actually develop huge amounts of lift (better than wing sails) but wing sails have a better lift to drag ratio (because they can have less drag)… In practical terms, this means that if you are underpowered (ie light winds) then soft sails are the way to go (because you need all the power you can get)… Once you have all the power the yacht can handle, then reducing the drag allows you to sail closer to the apparent wind… It all comes down to the “drag angle” which is a function of the lift to drag of the rig and the yacht combined…
Ice yachts and land yachts are both fast because they can sail with the apparent wind very far forward (especially on a reach)… This is because they have very good lift to drag… Multihull yachts are next best because they have decent lift to drag and huge righting moments where the rig weight is not a factor until the mass of the rig is to leeward of the lee hull (then things happen in a hurry!)… Monohulls are always fighting a losing battle against ANY extra weight aloft… and the relatively large hull drag limits the total lift to drag of the yacht… and therefore limits how far forward the apparent wind can move… This makes them a less than ideal candidate for a wing sail… Add in the difficulty of maintaining the proper angle of attack of the wing when you are not actually ON the boat (and it’s hard enough when you are)… and IMO your time is better spent in other areas…
On the subject of Hard-wings I believe what Jim and Bob say is right, and really appreciate your feedback, thank you, this is the reason why didn’t want to jump into a Hard-wings to start with but, first begin with a Mast-wing. I will wait for the body of knowledge & experience to grow on the Hard-wing level, before I walk this narrow plank :scared:
As you say Jim, vane for self trimming is a very practical solution for narrow range of settings required for Hard-wing for RC models.
Hew, I’m intrigued by the Orcale Hard- wing design, only thing I’ve seen is what Paulin posted from French magazine (attached) has anyone got anything else ?
Back to topic of Mast-wing design, I’ve come across the workings of Thomas Speer http://www.tspeer.com/ which is all theoretical, as he says, only because he does not can’t afford the testing to get experimental data however, he has the mathematical expertise that I don’t have on Mast-wings.
He talks about air flow Boundary layers & Laminar separation bubbles which I can understand as a lay-man. I take away reading his documents that higher angles of attack, narrow profiles are as effective as wider Mast-wings (with less drag) but the windward separation bubble of a wide profile on a low speed boat (mono-hulls) is not good at all.
Conclusion: the original plans I’ve posted …go in the bin for mono-hull project, but they maybe be acceptable for higher speed applications such as land or ice yachts and dare I say it … multi’s.!
Now looking into NACA 6 series designations for narrower Mast-wing at 25% of chord (thanks Jim)
Cheers Alan
P.S I’m not in my home time-zone so apologies for being a little short (sheesh jet-lag)
As noted elsewhere - Magnus Clark (CAN 1) C-Class is both an r/c builder/sailor as well as being the night babysitter for the BMWO wing during the last Cup event. Unless you hook with the design engineers of the big wing (doubtful they will spend much time with you) then Magnus is the nearest person who might be able to explain and discuss better with relationships to wings, how they work and “would” they work on a monohull. Not to dismiss some who have fooled with them, but unless the experimentation was done within the last two years, the old “ideas” are so far out of date, they really do a disservice to the most current designs and ideas. Again - if you haven’t read the thread in the Multihull Section on “wings” - please do so. Currently Magnus is down in New Zealand (I think) working as tech advisor for a wing system being constructed down there. I am not sure if it is for the 45 series, or for the next cup - but he’s been busy and hasn’t answered any emails lately.
Only suggesting that old ideas/trials that resulted in less than expected results may need to be reconsidered and retried. Someone in one of the forms asked why taper the top of the wing, and I think Bob’s post infers that too much material and too much power makes it too hard to compensate for righting moments… at least that is what I read into that portion of his post.
Sorry you are dumping your plans - and also sorry there are so many classes (monohull) that restrict development or trials - thus myths live on. :scared: :rolleyes:
It is great to see Bob Sterne on this forum.
I hope this finds you well Bob.
We have never met, but I have been a believer ever since I bought “Goldrush” the Canadian champion RM 1985? from Allan Gardiner.
Best wishes from a NZL “fan.”
Hi Dick, as you suggested, I read the thread started by nautibouy (Ray) on “WingSail Design” http://www.rcsailing.net/forum1/showthread.php?5641-WingSail-Design(was this the right thread?) very interesting insight on Hard-wing and the posts from MC with pics of wing built for his RC multi, unfortunately no further updates following the wing construction, no doubt his duties in Valencia had him on the run, would be great if he was able to update and add his experience & comments ?
Then Ray began building a wing 2.2 meter wing, before he was laid-up with fractured hip, that’s when the thread stopped a year ago …Ray hope your better & any chance of giving us an update on your wing progress ?
With Jim running now running up the wing learning curve, his feedback would be another interesting insight, and the Warkworth AC 45 construction has been as transparent as we will ever see, tons of photo’s and onsite construction web cams, so there is no shortage of opportunity for observation available for us humble modellers to see professional construction and learn more about of wings, is there ?
Hew thanks for the pics…
Funnily enough, I’m happy about dumping my first set of plans, as they proved to be wrong & saved lot of what would have been fruitless work, second set plans are in pipe-line while on work travel & hopefully when I’m back home (10 days) I’ll have something better suited for a mono-hull, I won’t let this beat me now, it’s been done before, that’s all the inspiration I need…thank you Francis Reynolds, only wish you could have shared your wing plans.
It can be a long road from conception to completion; and great old paradigms need modern landing gear, as well as wings that work.
"It is great to see Bob Sterne on this forum.
I hope this finds you well Bob.
We have never met, but I have been a believer ever since I bought “Goldrush” the Canadian champion RM 1985? from Allan Gardiner.
Best wishes from a NZL “fan.”
Thanks for the welcome, Ian… I would have loved to have met you “back in the day”… If you are ever vacationing in the southern BC interior look us up… it’s the only Motel in Coalmont…
As you may see the proportions and the setup of the wings are very different.
The huge 90 ft trimaran of the 33rd AC has a very slim high aspect ratio wing (thanks for these detailed drawings - I had never seen them before), while the new 45ft catamaran for the upcoming 34th AC was a much wider wing with only 3 elements.
Great stuff thanks for heads-up disabled some one is doing something on RC Hard-wing, excellent detailed work & will be watching this closely, looks little on the heavy side but what the hell it’s a start.
I see the question of wing profiles seems to be an open issue between AC 33 & AC 34 …
The Difference in wing design is down to making the AC 45 simpler to sail, reduction in production time and production cost to make the tight schedules. This is a ‘production series’ any way.
I would also like to bet that Oracle now has a huge amount of data regarding wing design and have been able to refine the design making it just as fast for less movable components.
For the AC 72’s you will see the gravitation back to more complicated designs as the teams experiment and try out their own ideas to try and catch up with Oracle…
Nice one disabled! Great to see the wing on the German site, Looking at the construction, the foam is 4mm Depron, and for the carbon covered parts there is Nomex core. Seems that is a no expense spared project.
I am interested in the final weight… but my guess is its lighter that you think…
Yes & that’s one reason to start with Wing-Mast, less parts and learn about basic wing profies firstly.
26.000 datapoints collected per sailed second …Guess the good old says of wetting the finger and holding it to the wind ain’t going to work anymore :lol::lol:
Ok finally decidied to go with straight wing mast profile (no Taper) and took into consideration tension adjustment for soft part of main sail, and settled for trianglar section, then main head 120 mm finally determined the final wing which works out to be @ 32% of main boom chord.
NACA 0012-64 is 6 mm narrower profile which if I understand correctly is just the right formula for low speed foils to work correctly, looks perfect when looking at laminar flows, has virtually no pocket on lee side and smooth transition with min sepration bubble on weather side @ 11 degree’s…far better than my orginal profile, thanks for kick in the pants on that one Jim.
Has anyone thought of ditching the built up rib wing and going with a foam core, fiberglass, vacuum bagged wing?
You could literally build a wing in 24 hours, from cutting the hot wire templates, to pulling out the bag. They are relatively light and strong (stress skinned) use a CF tube for a spar/mast rotation. A quick way to experiment with different foils.
Im currently building a cobra 5 and two round rangers from Craig. One of my thoughts was to use a solid wing sail to use as a B or C rig. Pretty much like the Oracle BMW trimaran shape but with a removable section. The idea of using foam core is tempting but in this subtile matter I would suggest using one of the expert services. LAzlo Hovart or Compufoam, provides precisely cut foam wing cores out of blue foam. His website is: http://www.compufoamcore.com/
His made foam cores for my gliders before and prices are great and precision is outstanding.
I was also thinking of the idea of using building jigs for each rib of the wing, using thin carbon fiber rod and solarfilm (it can be found here: http://www.radicalrc.com/category/Covering-Films-&-Tape-22 )
Not sure yet how should the wing work but I’ll try to make some heavy mock ups and see what type of control it should use. If using like the Trimaran wing, two wing surfaces there should be a way to use thin profiles and control camber. (maybe a weather vane, is that allowed in the RG-65 class? )
One thing to consider is that High aspect wings stall at higher angles of attack, but at the same time the require more speed to generate lift. Taking that into consideration is why I think of using the wing for a B,C replacement rig. Please if I sound like nonsense, I wont resent being corrected :rolleyes:
Anyway, I’m really moving forward with the building of the hulls so I can start concentrating on the wing design.
Enrico
I was into Tom Speer’s website and wing theory back in early 2000-2002 and my correspondence with him was that he posted theory, not experience. I’m not throwing rocks - and want to be sure you and other readers understand a batch of his info takes up space on my “multihulls” external hard drive - and I found some of his writing relevant and some “not-so-much”.
In 1983 a solid wing 18 Square Meter (18’ x 18’ with 194 sq. ft. of sail area) arrived at our North American Championships and really “cleaned” up. In 1984 it was (or nearly was) beaten by a soft sail, aluminum mast cat, and as I recall, it was eventually beaten for a series by that soft sail boat - memory fails me and I am not certain of the actual year - but suffice to say it was a while ago. Since then (28 years ago) a lot has changed in the world of wings, and some has remained the same. I only post in the hopes that following a series of written theories that may (or may not) work or have been tried doesn’t cause an unfavorable light on the good, bad, and ugly of solid wing sails. It is obvious this is still a technology for sailboats in it’s infancy. You just can’t walk into your local library and pick up 3 or 4 good books on wing sail theory and start building. It is for this same reason, on another forum, I cautioned a poster that photos of “blown up” wings are just a moment in time, and it is impossible to read anything into it - other than “something failed”.
As for our “other” thread, Ray had health issues withhis hip, so I guess he is still laid up for the winter. Magnus Clarke is working down in New Zealand (as I recall) and has had to step away from his r/c wing building. Thus, you get to proceed with your experiments in wing masts which will give you improved performance and the added knowledge to keep making the chord of the mast bigger and bigger until it turns into a solid wing sail. I am extremely interested in your succcess and failures and urge you to begin anew thread which is a blog of what you did and what you learned. Keep in mind also, that superlight builds can be reserved for what works. You can build a bit heavy for the testing of theory.
Please keep us posted, if you would and using Speer’s info, again - what worked and what didn’t?
some one is doing something on RC Hard-wing, excellent detailed work & will be watching this closely, looks little on the heavy side but what the hell it’s a start.
