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laser193713 View Drop Down
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    Posted: 15 May 09 at 3:54pm

but they have to take the mast down etc... and practicality is hardly an issue on the moth!

by the way were you at last years micro magic nationals?

 
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JimC View Drop Down
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Posts: 6662 		Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 15 May 09 at 4:09pm
Originally posted by laser193713

but they have to take the mast down etc...

So quite unlike, say, a Laser then?
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laser193713 View Drop Down
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Posts: 889 		Post Options Post Options   Quote laser193713 Quote  Post ReplyReply Direct Link To This Post Posted: 15 May 09 at 4:11pm
Yes, quite similar but a laser is an unstayed rig so it is much much easier! and also in lasers all it takes to get the mast down  is a nice 25knots and some waves and itll come crashing down, well half of it anyway!
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alstorer View Drop Down
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Posts: 2899 		Post Options Post Options   Quote alstorer Quote  Post ReplyReply Direct Link To This Post Posted: 15 May 09 at 6:37pm
Originally posted by Guest#260


747 wings don't need stays to hold them in place; aircraft have long since done away with stays.



It's much less noticable on smaller aircraft, but hae you ever sat in a 747 during takeoff with a good out along the wing? The tip rises relative to the fuselage a heck of a long way! This is, of course, taken into account in the engineering of it. Should also be noted that massive plane wings are engineered to flex in that one direction only- 747s are unable to do what I was watching a Eurofighter do this afternoon whilst my tests were running.
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RS400atC View Drop Down
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Posts: 3011 		Post Options Post Options   Quote RS400atC Quote  Post ReplyReply Direct Link To This Post Posted: 15 May 09 at 10:41pm

Since our boats don't do hundreds of mph, the drag of stays is generally outweighed by the reduction in mast section they enable. All boat rigs are compromises, but an aeroplane wing operates in a very different set of circumstances, so its compromises are pretty different. Ultralights are more comparable and I think they mostly have a good few rigging wires?

Unstayed is so simple for a Laser or Topper or very technical for a Finn. I once owned a Moth with an unstayed (wooden) rig, don't think anyone's tried that for a while? Not aware of any other una rig development classes where either could be used.

There have been production yachts with quite big unstayed rigs, but I don't think its ever been taken seriously for racing.

whatever happened to wing masts?
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 15 May 09 at 10:47pm
Originally posted by RS400atC

whatever happened to wing masts?

I have one

http://sailns14.org/tech.aspx

 
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m_liddell View Drop Down
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Posts: 583 		Post Options Post Options   Quote m_liddell Quote  Post ReplyReply Direct Link To This Post Posted: 15 May 09 at 11:02pm
Originally posted by JimC

Originally posted by laser193713

Wing masts are the attempt at making an efficient mast that works like a sleeved sail without needing to take it down all the time


Not really no. A sleeve sail doesn't address the main problem of a round section mast, which is that a constant radius leading edge - ie a round tube - isn't the cleverest of sections as the airflow splits in advance of the blunt leading edge.

A good wing mast, by contrast, will have something like a hyperbolic curve section on the leading edge which, when correctly aligned to the airflow, will in theory have both much lower drag and create lift as well.


Indeed, a bluff body in front of a sail is never going to be ideal.

Some research on wing masts for anyone interested: http://www.tspeer.com/Wingmasts/teardropPaper.htm
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tgruitt View Drop Down
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Posts: 2479 		Post Options Post Options   Quote tgruitt Quote  Post ReplyReply Direct Link To This Post Posted: 16 May 09 at 12:06am
Originally posted by laser193713

but they have to take the mast down etc... and practicality is hardly an issue on the moth!

by the way were you at last years micro magic nationals?

 



Indeed I was. I was sailing number 34, which I borrowed for the event. Which one were you?
Needs to sail more...
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alstorer View Drop Down
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Posts: 2899 		Post Options Post Options   Quote alstorer Quote  Post ReplyReply Direct Link To This Post Posted: 16 May 09 at 9:37am
Of course, when it comes to unstayed masts on big boats- there's two high profile examples I can think of.
Exhibit A had big problems with the mast heel bearings on its twin wingmasts.


Exhbit B isn't really a racing boat (though it is cheerfully capable of 20knots under sail)

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Al
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JimC View Drop Down
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Posts: 6662 		Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 16 May 09 at 10:56am
Originally posted by RS400atC

I once owned a Moth with an unstayed (wooden) rig, don't think anyone's tried that for a while? Not aware of any other una rig development classes where either could be used.

There have been such rigs recently in both Moths and ICs.
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