Solid 'Wing' sails?
Printed From: Yachts and Yachting Online
Category: Dinghy classes
Forum Name: Dinghy development
Forum Discription: The latest moves in the dinghy market
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=12763
Printed Date: 05 Jul 25 at 7:00pm
Software Version: Web Wiz Forums 9.665y - http://www.webwizforums.com
Topic: Solid 'Wing' sails?
Posted By: ColH
Subject: Solid 'Wing' sails?
Date Posted: 06 Jun 17 at 6:17pm
|
Are there any classes using or trying solid wing sails a la AC boats?
Would they ever be feasible for a dinghy? Perhaps a Moth - which you can probably tuck under your arm and stroll down into the water with anyway! |
Replies:
Posted By: JimC
Date Posted: 06 Jun 17 at 6:24pm
The C Class catamarans invented them and have been using them for decades. The big problem is that they are a damn nuisance. A C class event really needs covered accommodation for every competitor.
|
Posted By: ColH
Date Posted: 06 Jun 17 at 6:39pm
| Yeah jim, I did think of cats like that, after posting. But was more pondering the possibilities in dinghies in particular. |
Posted By: ColH
Date Posted: 06 Jun 17 at 6:40pm
Is it car-toppable....? 
|
Posted By: Oinks
Date Posted: 06 Jun 17 at 6:41pm
| Cool for Cats...but not much else I'd suspect! |
Posted By: Oinks
Date Posted: 06 Jun 17 at 6:59pm
| Interested to know why this latest breed of cats are so noticeably nose-down than the previous AC cats? |
Posted By: ColH
Date Posted: 06 Jun 17 at 7:04pm
Has been under discussion in the AC forum here |
Posted By: 423zero
Date Posted: 06 Jun 17 at 7:10pm
| How much more efficient are they compared to the best normal sail ? |
Posted By: ColH
Date Posted: 06 Jun 17 at 7:16pm
Good point. Maybe its just that given the size and apparent wind speeds, they're more controllable/predictable? |
Posted By: JimC
Date Posted: 06 Jun 17 at 7:31pm
Over double *sail only* efficiency I believe. Of course the rest of the plot has to match, you won't get much benefit if the boat is limited by the hull design anyway. |
Posted By: 423zero
Date Posted: 06 Jun 17 at 7:50pm
|
What happens if you over power hull design ? For instance if you fitted one to a Laser, same area sail, but solid.
|
Posted By: JimC
Date Posted: 06 Jun 17 at 8:48pm
| I don't know enough about the fine detail of the Laser performance to be able to comment much. At an utterly uninformed guess the boat would probably be a bit faster upwind, a bit faster still crosswind, but maybe not improved running. Oh and do 500 quids worth of damage every time you capsize... |
Posted By: Presuming Ed
Date Posted: 06 Jun 17 at 9:19pm
Been tried in a couple of moths. Doesn't mix with capsizing. |
Posted By: 423zero
Date Posted: 06 Jun 17 at 9:26pm
| Was it faster ? |
Posted By: Rupert
Date Posted: 06 Jun 17 at 9:42pm
|
Faster if you get the settings right, but pretty unforgiving. ------------- Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686 |
Posted By: JimC
Date Posted: 06 Jun 17 at 9:45pm
|
They didn't win.
I don't think anyone is in doubt that the solid rigs are potentially faster, especially if there was some relaxation of the Moth rules which prevent slots in the rig. Whether they are a good thing is another matter. There's the awful example of the C Class, which has been the most interesting and technically sophisticated class on the planet for the last 40 years or more, but also perpetually balanced on the edge of extinction because so few folk can afford to campaign them. The purpose of class rules is, after all, to enable people to have fun competing in sailing boats, so if next to no-one can afford to compete then that suggests a problem with the rules. |
Posted By: 423zero
Date Posted: 06 Jun 17 at 9:51pm
| I wouldn't think they will become an issue anytime soon, well not unless someone comes up with a cheap fairly indestructable set, oh and you would have to be able to store the wing |
Posted By: tgruitt
Date Posted: 07 Jun 17 at 12:44pm
------------- Needs to sail more... |
Posted By: tgruitt
Date Posted: 07 Jun 17 at 12:49pm
------------- Needs to sail more... |
Posted By: tgruitt
Date Posted: 07 Jun 17 at 12:52pm
------------- Needs to sail more... |
Posted By: SUGmeister
Date Posted: 07 Jun 17 at 4:28pm
|
They were testing a wing rig on a tornado catamaran back in 2012, tho apparently this was part of Artemis's AC72 development. Looked good tho... http://www.youtube.com/watch?v=9yemIJCBSRU" rel="nofollow - https://www.youtube.com/watch?v=9yemIJCBSRU [TUBE]https://www.youtube.com/watch?v=9yemIJCBSRU[/TUBE]
------------- Simon SUGmeister I wondered why the baseball kept getting bigger. Then it hit me. |
Posted By: Sam.Spoons
Date Posted: 07 Jun 17 at 5:39pm
|
Looks pretty unpleasant to sail with a lot more pitching than I'd expect with a soft rig. ------------- Spice 346 "Flat Broke" Blaze 671 "supersonic soap dish" |
Posted By: 423zero
Date Posted: 07 Jun 17 at 6:08pm
| Just watching made me queasy, looked ready to pitchpole at any second. |
Posted By: Rupert
Date Posted: 07 Jun 17 at 7:21pm
|
The Tornado (no2) had a wing mast in 1967 for the IYRU trials. It had too many teething troubles, so the soft sailed version won out easily. ------------- Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686 |
Posted By: JimC
Date Posted: 07 Jun 17 at 8:08pm
|
The Glorious Cs aren't getting nearly enough credit...
1974 
1985 
1987 
(from http://tonyl10.blogspot.co.uk/" rel="nofollow - http://tonyl10.blogspot.co.uk/ ) 2007 [tube]u_UigYQSbYY[/tube] 2013 [tube]rjcbjCv92JM[/tube] |
Posted By: Sam.Spoons
Date Posted: 07 Jun 17 at 8:30pm
|
Fab, I remember lusting after one as a teenager. looking with more experienced eyes I'd be interested when they became overpowered.... looks like about 12 knots based on those three pics :) ------------- Spice 346 "Flat Broke" Blaze 671 "supersonic soap dish" |
Posted By: Chris 249
Date Posted: 09 Jun 17 at 4:03am
|
I'm still dubious about whether wingsails are amazingly quick, apart from in C Class cats (where arguably they are to a significant extent a product of the rules) and in the extreme high speed AC boats. Over on Boat Design Forum, aerodynamic experts and AC wing designers Prof Mark Drela and Tom Speer have repeatedly noted that there is not really anything inherently superior with wingsails. A couple of quotes; Mark Drela - "Thin airfoils are capable of the highest CL and CL/CD values.....such a thin airfoil is pretty much out of the question on an airplane, even before structural consideration are brought in. But a soft sail allows the possibility of changing the camber of a thin airfoil, which can greatly extend the low-drag range if done appropriately. So a thin airfoil which always has the appropriate camber shape dialed in at any given operating point will in general be superior to a thick airfoil. " Mark Drela again: "What type of wing or sail is best for any type of vehicle depends a great deal on what dominates the drag of the vehicle...On a sailplane, the D_wingsail (wing profile + induced drags) is nearly everything. D_parasite (fuselage + tail) is tiny by comparison. So L/D ~ L / D_wingsail which is maximized with a slender cantilever wing like you see on any sailplane. But on a sailboat, D_parasite (hull hydro + aero drags) is huge by comparison. So to maximize L/D you want a large http://www.cruisersforum.com/forums/tags/lift.html" rel="nofollow - lift L to "dilute" this large D_parasite, even if D_wingsail is also made large as a result. Large http://www.cruisersforum.com/forums/tags/lift.html" rel="nofollow - lift naturally favors multi-element sails, for all the reasons listed by AMO Smith. This is especially the case if the sail area is constrained by rules or whatever." In C Class cats and AC boats, the hull drag is very, very low and the stability and apparent wind speed is high; it would all seem to add up to an area where the wingsail works well (obviously). But dinghies, keelboats and smaller cats are dominated by different issues, like higher hull drag and righting moment limits, so it's not surprising that wingsails have failed in such classes. Tom has also noted that the wingsail in the AC cats is structurally superior because it solves the problem of high mainsheet and vang loadings. They are not such an issue in other craft. Personally I find it's really interesting that the information from guys like Tom Speer and Mark Drela actually matches what we see in real life, where wingsails (and wing masts) do not normally perform anywhere near as well as many theories would have us believe. There was a really interesting post or two from the guys behind the C Class Invictus when they raced a fleet of F18s, Nacra 20s, F16s etc. They got beaten badly, partly because of lack of practise and partly because of a breakage. However, when a 25 footer gets beaten up by 20-16 foot production boats it's an interesting illustration that wingsails seem to have issues.
------------- sailcraftblog.wordpress.com The history and design of the racing dinghy. |
Posted By: ian.r.mcdonald
Date Posted: 09 Jun 17 at 6:08am
| I remember the sad sight of Lady Helmsman, hulls seperated and propped up against the fence at Thorpe Bay YC |
Posted By: Rupert
Date Posted: 09 Jun 17 at 2:17pm
|
One reason for wings in the C class was the small sail area allowed, so they had to look at other ways of producing ore power. ------------- Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686 |
Posted By: I luv Wight
Date Posted: 09 Jun 17 at 7:08pm
|
http://realisedesign.co.uk/wp-content/uploads/2010/09/ben_dsc0368.jpg" rel="nofollow - http://realisedesign.co.uk/wp-content/uploads/2010/09/ben_dsc0368.jpg Another moth pic ------------- " rel="nofollow - http://www.bloodaxeboats.co.uk" rel="nofollow - http://www.bloodaxeboats.co.uk Andy P foiling Int Moth GBR3467 Freedom 21 Codling |
Posted By: Rupert
Date Posted: 09 Jun 17 at 8:48pm
|
Was that really 7 years ago? ------------- Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686 |
Posted By: Chris 249
Date Posted: 09 Jun 17 at 11:07pm
------------- sailcraftblog.wordpress.com The history and design of the racing dinghy. |
Posted By: Sam.Spoons
Date Posted: 10 Jun 17 at 9:49am
|
That's only true if you include the kite (which the C Class doesn't have). The C Class has 27.9 m2 upwind and the F16 has 18.7 m2. ------------- Spice 346 "Flat Broke" Blaze 671 "supersonic soap dish" |
Posted By: Chris 249
Date Posted: 12 Jun 17 at 8:08am
|
Sure, but the fact remains that downwind the C Class' rig is comparatively small, which must have a very significant effect on rig design. Even upwind it's not a huge rig compared to some fast 20 footers. The Supercat 20 carries 25.5m2 of sail upwind; Eagle 20 25; Hobie 20 23.2; Nacra 20 24.15, Nacra 20C 26. The Marstrom 32 has 53.6m, the Marstrom M20 22 and A Class 14. The C Class is halfway between the A and M32 in length, but the sail area is well under halfway between the two. Many years ago I watched the top C Class Victoria 150 race the unlimited 18 Foot Skiffs. The C Class won overall quite easily but was slower down the squares than the 18s despite being soooo much longer.
------------- sailcraftblog.wordpress.com The history and design of the racing dinghy. |
Posted By: Sam.Spoons
Date Posted: 12 Jun 17 at 9:45am
|
My gut feeling (which may be completely wrong ) is that a wing is going to be more efficient upwind than a conventional sail but probably not so off wind. A big asymmetric kite would solve that. Those long cat hulls don't really have a displacement mode and a planing mode like a mono. I'd be interested to know how much difference WL really makes on a fast cat. ------------- Spice 346 "Flat Broke" Blaze 671 "supersonic soap dish" |
Posted By: ttc546
Date Posted: 12 Jun 17 at 11:33am
Maybe, maybe not. Speed moves the apparent wind, so kites can become useless downwind.
------------- |
Posted By: Sam.Spoons
Date Posted: 12 Jun 17 at 1:05pm
|
Good point but it can't happen most of the time or cats wouldn't bother with assy kites at all? ------------- Spice 346 "Flat Broke" Blaze 671 "supersonic soap dish" |
Posted By: Rupert
Date Posted: 12 Jun 17 at 1:57pm
|
They tend to be quite flat cut. ------------- Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686 |
Posted By: Sam.Spoons
Date Posted: 12 Jun 17 at 7:44pm
|
I had guessed that, my Spice kite wouldn't be much use on a cat then ;) ------------- Spice 346 "Flat Broke" Blaze 671 "supersonic soap dish" |