| Are wing masts practical for small cats? #17134 03/10/03 05:03 PM 03/10/03 05:03 PM |
Joined: Nov 2002 Posts: 5,558 Key Largo, FL & Put-in-Bay, OH... Mary OP
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Posts: 5,558 Key Largo, FL & Put-in-Bay, OH... | Are wing masts feasible for use on small cats? During all this recent controversy about the Little America's Cup being revived, some people have talked about putting wing masts on the F-18HT's and others have mentioned that C-Class technology, including wing masts, could be adapted to smaller cats, as well.
But first of all, I am not clear on whether people are all talking about the same thing when they refer to wing masts. There are wing masts that are just normal masts with a fabric sail but the mast is deeper from front to back. And then there are very deep wing masts with a relatively small section of soft sail, and then there are wing masts that are totally hard wing. So what is the correct terminology for these various types of wing masts?
And, also, I vaguely remember that in the early days of the Tornado, they were experimenting with a wing mast (deep wing with some soft sail??) and, although it was faster than the soft sail, it was rejected as not being practical because the mast had to be lowered whenever the boat was on shore -- too unstable and blew over too easily. | | | Re: Are wing masts practical for small cats?
[Re: cappydec]
#17136 03/10/03 09:26 PM 03/10/03 09:26 PM |
Joined: Nov 2002 Posts: 5,558 Key Largo, FL & Put-in-Bay, OH... Mary OP
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Posts: 5,558 Key Largo, FL & Put-in-Bay, OH... | Right, they are all considered wing masts, but that is why we need terminology to distinguish between the different types and degrees of "wing." Lilke mini-wing, half-wing, full wing? | | | Re: Are wing masts practical for small cats?
[Re: Mary]
#17137 03/11/03 02:47 AM 03/11/03 02:47 AM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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Posts: 9,582 North-West Europe | As far as I know Fully riggid sails are called wingsails while long cord masts (often with a much flatter profile) are called wingmasts. In literature wingmasts with soft sails behind it are often refered to as so and so % wingmasts. For example a soft sail rig with a wingmast that has a cord of 30 % of the overall average cord of the compet rig is refered to as a 30 % wingmast rig. Of course wingsails come in different shapes. You can have a wing out of one section or have a wingsail that is made up from several vertical section that are spaced a little apart. These wingsail are often described by the number of slots that are between the segments. A two part wingsail is than refered to as a single slotted wingsail. Three part wingsail as as a double slotted wingsail and so on. In the case of miss nylex which had three segments but where the rear panel was split into two (almost) vertical alligned flaps the wigsail is still refered to as a single slotted wingsail despite the fact that it was made up out of three segments. The reason for it is that from a aerodynamic point of view it behaves as a single slotted wingsail. Hope this helps although I'm often told that I don't know my rear end from sailing technology. So I could be completely of the mark here. Wouter
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
| | | Being practical
[Re: Mary]
#17138 03/11/03 02:52 AM 03/11/03 02:52 AM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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Posts: 9,582 North-West Europe | with respect to being practical ?
well no not really but if your hot enough on spending money and effort to buy yourself a considerable advantage both upwind and downwind than, yes, there is nothing technical stopping you from putting one of these on your platform.
I mean people also disassemble and drive around glider with more than 25 mtr. oerall wingspan planes in enclosed trailors why chouldn't the same be done with the seperate panels of say a doubleslotted wingsail ?
wouter
Wouter
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
| | | Summary
[Re: Wouter]
#17140 03/11/03 09:11 AM 03/11/03 09:11 AM |
Joined: Aug 2001 Posts: 1,307 Asuncion, Paraguay Luiz
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Posts: 1,307 Asuncion, Paraguay | Mary, Wouter explained it all. I just want to summarize: -A rigid sail (with or without a separate mast) is a wingSAIL. -A rigid streamlined rotating mast with a soft sail behind it is a wingMAST. -Combinations of both exist, so these definitions are not final. -WingSAILS use airplane wings terminology, slots, flaps, etc. -WingMASTS with soft sails use normal terminology - except for the mast chord/rig chord % ratio. -The chord of the rig in its foot is the foot length plus the mast chord. The mast chord is the length of its section. PS - I don't know for sure is if the correct spelling is "Chord" or "Cord"... PS2 - Bill Roberts worked in the development of wingsails and is certainly on of the best references, if not the best, on the subject. PS3 - In my opinbion, unless new technical solutions to reef and fold rigid wingsails are developed, they are not practical for small cats. Wingmasts with bigger chords seem to be the best choice today, because very light masts can be built in carbon - weight was one of the main restrictions preventing wingmasts to have longer chord.
Luiz
| | | it is more a question of ...
[Re: Mary]
#17142 03/12/03 03:05 PM 03/12/03 03:05 PM |
Joined: Jun 2001 Posts: 9,582 North-West Europe Wouter
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Posts: 9,582 North-West Europe | it is more a question of the ratio between the cord and the thickness of the mast section that determines wether it is refered to as a wingmast rather than a "normal" mast. Although general shape of the crossection comes into play too.
Yes, I didn't invent this way of calling things too.
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
| | | Grey area
[Re: Wouter]
#17143 03/13/03 08:19 AM 03/13/03 08:19 AM |
Joined: Aug 2001 Posts: 1,307 Asuncion, Paraguay Luiz
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Posts: 1,307 Asuncion, Paraguay | Mary / Wouter
I think that this is a grey area, mainly because I can not think of any strict or final definition.
A reasonable definition would be:
"A wingmast is a mast that adds (more lift then drag) to the rig's performance".
The problem is that the same mast could qualify or not according to wind speed and angle.
I can not think of a definition that does not include "averages" or "initial conditions" that necessarily make them less general, those conditions and averages being grey areas themselves...
By the way - I thought all streamlined rotating masts commonly found in beach cats were wingmasts.
Luiz
| | | Re: Summary
[Re: carlbohannon]
#17146 03/13/03 12:30 PM 03/13/03 12:30 PM |
Joined: Aug 2001 Posts: 1,307 Asuncion, Paraguay Luiz
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Posts: 1,307 Asuncion, Paraguay | ...wait till it's really blowing, turn the boat beam to wind, and then play with the rotator... Yeah, but one could argue that under bare poles it's not a wingMAST anymore - it's a wingSAIL A tall and thin one, but still a wingsail... Tight definitions are slippery. Grey is beautiful!
Luiz
| | | Re: Are wing masts practical for small cats?
[Re: Mary]
#17147 03/13/03 03:09 PM 03/13/03 03:09 PM |
Joined: Nov 2002 Posts: 5,558 Key Largo, FL & Put-in-Bay, OH... Mary OP
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Posts: 5,558 Key Largo, FL & Put-in-Bay, OH... | I am going to reply to my own question here.
I just talked to Ben Hall of Hall Spars. He makes masts for a living, so I asked him what a wing mast is. He said there is no real definition anywhere, but he would consider any of the conventional, air-foil-shaped, rotating masts that are on most modern catamarans to be wing masts. As far as he is concerned there is no particular chord length and no magical ratio between chord and mast thickness that determines what a wing mast is.
He said an A-Class mast is about 5 3/4 inches by 2 1/4 inches, which is not substantially different than the masts on Hobies, Nacras, etc.
He said the deeper the chord of the mast, the less practical it is for small cats, and a full, solid wing mast (wingsail) is totally impractical, because:
#1 They are very fragile and usually get wrecked if the boat capsizes. #2 You have to take them down every time you are on shore, because the boat can blow over so easily. #3 You need a team of three or four people to raise and take down the mast, because of its fragility. #4 You need some sort of box ("violin case" was the term he used) to cover and protect the mast because if somebody just trips over it while walking past, it can damage the fragile surface of the mast.
"The full wing mast is esoteric and beautiful," Hall said, "and I would love to have one on my A-cat, but it is just not practical." | | | Re: Are wing masts practical for small cats?
[Re: Mary]
#17148 03/13/03 04:25 PM 03/13/03 04:25 PM |
Joined: Apr 2002 Posts: 805 Gainesville, FL 32607 USA dacarls
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Posts: 805 Gainesville, FL 32607 USA | Ah, now I see...Wing masts are soooo like women!
Dacarls: A-class USA 196, USA 21, H18, H16 "Nothing that's any good works by itself. You got to make the damn thing work"- Thomas Edison
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