Hi Claudio, Just to clearly understand, are you saying is that Wingsail Monohull will not work ? …when reading the section of Francis article about his experience on his Mono hull with Winged Sails called CD Min, he says:
[i]Using our wind-tunnel data I first put a small wing sail on a pair of catamaran hulls of my own design, calling her “Katy Kat.” But I soon discovered that cats are no damn good on small closed courses. Because of their light weight and low inertia they tend to lose headway on turns across the wind for tacks and buoys, ending up dead in the water or drifting aft.
My next and final wing-sail effort was “CD Min,”(“Minimum Drag Coefficient”). I remember negotiating with the MYRAA over whether a wing-sail boat would be legal in DX competition. At first they said that wing-sails would not be allowed; but I persevered, arguing that progress in boat design was important. The powers-”that-were” finally relented and agreed to let me race such a model, providing that I limit the total sail area to 1000 square inches. So I ended up with an X-class size boat. That was better than an M racing against A’s, but still quite a handicap.
I guess the sail-area limit the MYRAA imposed on “CD Min” was about right since her technical advantages made up for it and she was competitive. She didn’t win all of her races but she never placed lower than third in National, Pacific Division, or Northwest Association DX competition.[/i]
I always appreciate your opinion but fail to understand what your saying, can you explain your point of view further please ?
Mostly due to the rules, most classes prohibit them. 10R’s allow them, but they measure as twice the area of a soft sail. With that handicap they might not work well enough to be used. Also people are used to soft sails, how to make them and how to tune them. A wing sail is something new. I plan on trying one on my RG-65 to see if there is an advantage. My guess is there is a big advantage if it is made the same area as a soft sail.
If one could had proven the validity , a new class would have born !!!
the efficiency of the rigid sail is coming from the speed it can achieve, unfortunately a boat equipped with an heavy bulb cannot accelerates, because of the inertia, as the rigid sail would requires, therefore… it is also dangerous for the wing, because under a sudden gust it may breaks because the boat has no time to accelerate…expecially during running !
cheers
ClaudioD
Claudio is pretty much correct. A displacement hull seldom exceeds it’s hull speed - and seldom can continue to plane for any length of time. A solid wing (not mast) needs a high speed air flow to develop its greater power. As the boat moves faster through the water, the wing helps develop its own apparent wind. Boats with litttle friction (cats, trimarans, ice boats, land yachts, and foilers) usually have the ability to make use of higher wind speeds, which in turn generate higher hull speeds, which in turn … etc. I would offer my own opinion that a wing sail with the same surface area of a soft sail would probably be faster - to a point. How much is dependant on how well either are tuned, trimmed, and if the hull can handle the added speed if hit by a gust. Because of the lead bulb, there are laws of physics that just won’t let you sail faster than (usually) the calculated expected hull speed, give the same area of sail surface.
But - there is always a desire to experiment, and you may just hit on the right combination of area, friction, etc. to find a better way.
The EC-12 class outlaws auto-sheeting by saying “controlled only by the skipper”.
10.0 RADIO FUNCTIONS
10.1 A maximum of four radio functions may be employed, and controlled only by the skipper, to control only the following items by electronic and/or mechanical devices:
Rudder, Main sheet, Jib sheet (or jib trim), Jib twitcher
Claudio & Dick, thank you and your right on all the points you make … but the biggest problem to over come is people fear of change, it rules the world…SADLY
Ain’t life a bitch when you’re not a multi-billionaire :lol: only option is to become a sheep, like everyone else and follow the herd as usual …
I agree that the extra weight aloft, and heeling angles of monohulls would not benefit from solid wings.
That being said, combine a flapped wing in conjunction with a canting keel, and you can eliminate most of the problems! The wing stays vertical and you can use a narrow, cat-like hull. There could be problems controlling the cant that may need to be automated. This arrangement can also be self righting
I am slowly thinking about how to make it work. I think for the Re range a RG operates there will need to be a flap in the wing to get good performance. Most low Re sections that I have seen are all underchambered. The question is how to make the flap automatically switch sides when the rig tacks. Also now that I think more about it, the A rig might not be the best choice since in the light stuff the wing might not tack well. You could loose more than you gain very quickly. Now for a B rig there should be plenty of force available to make the wing change camber.
I’m now starting to build 1.5 metre wing mast to start with …I found this site has some good info from land yachts and the “rig design” section as some simple ideas with sail design tools to help work out the basics. http://www.rclandsailing.com/design.html
I like the variable softsail size idea to quickly change sail area using luff slot in the leech edge of wing mast…good experimental base to work & learn with.
For some info on wing sail this site helps give you some direction to start with, they"re over selling the concept a little but the basics are there.http://www.omerwingsail.com/operation/
Hope it helps & will update progress on this little winter project
just a reminder that we had some lengthy discussion under the "Multihulls threads about solid wing sails too. Ray Paice (UK) and Magnus Clark (Canada) put forth some great ideas, suggestions and Magnus (being tied to BMWO as the night wing-sitting manager) plus his experience on teh Canada’s 2 time Championship C Class catamaran lent valuable insight on the wing, how to possibly build and control an r/c one.
May want to take the time to find and read that series of posts.
For wing masts - email Mark Gee (AMYA Class secretary) for the 10 Raters which allow and he has used a rotating wing “mast”.
Dick
ADDED: Ummmmm - watch out for things like this which tend to hit a budget pretty hard. :rolleyes:
I have sailed against Mark’s wing masted 10R and used waliki wing masts on my 10R as well. I like the idea of doing a large wing mast with a small soft sail. With the way the 10R rules, than is not a viable option. Too much sail area loss if the wing portion gets too big.
My Imagination plan … building the wing mast to fit on my #2 ETNZ hull without any major surgery, then can see how it goes ? against #1 ETNZ with 74 dm2 conventional sail plan.
Will run groove in leech of wing mast to be able to change-out different sized soft sails & adjusting rough helm balance with normal deck mast step.
Why taper the wing portion of the sail plan. I would just keep it straight and then have a smaller soft section at the top. It will hold its shape better too.
very interesting discussion on the first protype wingsails being tested at ZHIK 2011 moth worlds in Aussie
… “easy to build anyone can do it, if you have made RC plane model” your my man BORA !!!
Sorry for double posting,
but I couldn´t hold back!
My basic question to this topic:
Why build a fast wing - to put in on a slow boat?
Doesn´t make sense to me.
But on the other hand - I´m just a stubborn multihull-freak -…-
eh ! hey disabled with all due respect your out of topic if you read this thread, it is titled Wingsail Monohull … if you had taken the time to read from the beginning of this thread wingsails are nothing new, but sadly 99% of mono hull classes have banned them !!! finally they have found a home on multi-hulls … and well done to the multi hull community.
If your into multihulls then I’m happy for you, no-one here is not knocking them, but once again your in the you’re in wrong place…
if you read this thread, it is titled