Wing Sails

[claudio]

HI every body,
I would like to make a Wing Sail for my class M but not limited to.
Is anyone that has already tried this technique may suggest some solutions ? Rigid, semirigid, soft sail.
Just an interesting picture here below and an interestig adress : http://perso.wanadoo.fr/amn.minifoiler/id75.htm
Claudio

[Bill Korsgard]

HI every body,
IIs anyone that has already tried this technique may suggest some solutions ? Rigid, semirigid, soft sail.

Claudio,
Very interesting website, thanks!

If you do a search under "wingmast", you'll see a fair amount of past discussion on the subject. Most of it pertains to applications on multihulls & landyachts.

Regards,
Bill K

[FunnyBones]

Does a wingmast make a jib redundant? Or is there some benifit in a leading edge slot device still?

NL

[claudio]

Thanks you Bill.
The question of FunnyBones is very interesting, personally I do not knows yet . Any hints ?
Claudio

[Bill Korsgard]

Does a wingmast make a jib redundant? NL

Nick & Claudio,
I would say no, the jib could very well be usefull. However on faster moving craft where boat speed will exceed windspeed (landyachts, iceboats & to some extent multihulls), there will be a point at which the jib will create more drag than lift & limit top end speed.
Bill

[claudio]

This is my starting idea. I would like to use a soft wingsail on my Class M
Any suggestion from someone that already tried similar construction %
I will be gratefull to have some opinions even the negative ones.
Thank you all.
Claudio

[Dick Lemke]

Claudio -

any particular reason you are adding the balsa to the front of the mast to produce a curved entry for the sail? Since the mast is already round, it seems redundant.

For a while, many of the larger trimarans used "ribbon" jibs, which, as the name implies were merely long strips of cloth used to get a bit more flow over the main. In most cases, the solid wing sails (or soft wings) have sufficient power, that they seldom need more or speeded up airflow. The following flaps generally are used to add camber to the wing, and to preven detached flow. As Bill suggests, the speed of the boat will usually offset any jib improvements. Some multihulls, and most iceboats or land sailers will have a jib collapse from the speed/force of the wind. It is also known that some ccatamarans will actually point higher without a jib, than with one. Off-wind without a jib is another story. You have to take the bad with the good.

A fellow working for me is experimenting with a solid wing landyacht, photo below, but is still in the construction phase. He mentioned that even without any fabric/film covering, the boat was moving along his driveway with only the leading edge covered.

[claudio]

Dick,
I was inspired by the aerodynamic notion where the circular rod presents a Cx = 1.2 and the elliptical form exibit instead a Cx = 0.11 ( Re =100000).
Thank for your advise about the jib.
Revisiting the question I'm actually intentioned to change drastically the surface ratios 85% for the main and 15% for the jib. The jib in fact will be very narrow and according to my view should acts as a front "flap" like on the real airplane wings more or less as you described with the "ribbon". Obviously all that imposes a change on the hull desing and centering since the CE will be close to the main center and the mast shall be advanced toward the bow, etc.
Claudio

[Bill Korsgard]

This is my starting idea. I would like to use a soft wingsail on my Class M
Any suggestion from someone that already tried similar construction %
I will be gratefull to have some opinions

Claudio,
I must say, I really like the shapes you've come up with. Here are a few comments:

-Will the CF tube be allowed to rotate?
-Will the backstay crane rotate in the tube?
-Although the curved mast looks cool, I doubt that the added complexity in construction is justified by aerodynamic gains.
-What is the "moletton" material? I've never heard that term.
-Lester Gilbert pointed out some valid concerns about sleeved sails in the "sailmaking" thread recently.
-We have a saying in this country: "The devil is in the details". You may need to do a fair amount of prototype work to achieve the cross section shown in your idealized drawings. Keep in mind that the actual shape will be largely controlled by sail pressure, thus will be contantly changing to some extent.
-Will the change from one camber to the other be without wrinkles in the fabric & with minimal friction?
-I understand there are some sleeved sail rigs being used on 10 Raters in Britain. They are reported to be lighter than similar wingmasts made out of solid material. Weight aloft is always a major consideration, especially when 2m high.

Regards,
Bill

[claudio]

Bill,
actually the mast is fixed. The balsa profile (it will be a carbon sheet) supported by rings along the mast and the sleeve are attached together and are the rotating part including the sail.
Molleton : in my dictionary = battting, duffel, soft flanel, swan's down. This synthetic material is largely used for quilting and support the washing machine. Used here as a soft filler to compensate wind pressure.
Here the sketch of what I would like to do. Expecting comments of course.
The bent mast, is actually left in the idea"s corner, obviously introduce an additional difficulty, but wrinkles along the Luff can be avoided by splitting the sleeve in panels .
I will watch for the Devil !
Claudio


just a sample !