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Kites! Kites! Kites! => Beginners Corner => Topic started by: kitechick on October 30, 2009, 05:39 PM



Title: Sail stretch
Post by: kitechick on October 30, 2009, 05:39 PM
I've been warned by a few people of flying in too high of winds for a kite and stretching the sail. How do I know how much wind is too much? Can I fly to the upper end of the stated wind range for the kite without stretch? What are the repercusions of a stretched sail?

Fyi, I fly a silver fox and widow maker UL (though I'm not a flyer worthy of it).

Laura


Title: Re: Sail stretch
Post by: thief on October 30, 2009, 05:44 PM
if your skin stretches the spars will no longer fit....
but the only kites that I know of that really have a stretching problem would be any kite made of carrington (Mostly uk kites from the late 90s)....

fly the kite....enjoy it.....if it gets stretched out then it is a perfect reason to get a new kite!!!!!

r


Title: Re: Sail stretch
Post by: DWayne on October 30, 2009, 05:56 PM
I wouldn't worry about it at all. Your Widow Maker is made of icarex. It won't stretch. I doubt that your Silver Fox is made of a material that's prone to stretching either. Just fly them and have fun.  ;)

Denny


Title: Re: Sail stretch
Post by: Allen Carter on October 30, 2009, 08:40 PM
Yup, stretching isn't an issue with modern kites. Even with nylon sails that can stretch, its more a matter of overall airtime than incidents of extreme wind. In high wind breaking sticks and lines is more a concern. A framing failure in high wind can lead to severe sail damage. Make sure all your fittings are snug.


Title: Re: Sail stretch
Post by: Gamelord on October 30, 2009, 10:03 PM
Even though the WM UL is made from Icarex, I wouldn't recommend taking it out in anything much over 8ish mph max.


Title: Re: Sail stretch
Post by: normofthenorth on October 31, 2009, 12:31 AM
In the case of sailboat sails -- which often go out in pretty strong winds -- stretch ends up being a serious problem, even in Dacron or ripstop nylon sails. (Icarex is still rare on boats.) It's usually most noticeable right near the trailing edge, especially when there's a hem (and/or a "luff line") along the edge.

The hem is strong, so it doesn't stretch, but the cloth adjacent to the hem stretches and makes a billow, like a Frisbee. I bet a well-used (or abused) kite might start showing a similar Frisbee profile toward the end of its life. . .


Title: Re: Sail stretch
Post by: fidelio on October 31, 2009, 12:56 AM
so why can't we get kites made of end of life pre-stretched sail material? :D


Title: Re: Sail stretch
Post by: DWayne on October 31, 2009, 05:37 AM
so why can't we get kites made of end of life pre-stretched sail material? :D

Because most sail cloth is too heavy to use in sport kites. Its only the light spinnaker cloth that's used.

Denny


Title: Re: Sail stretch
Post by: fidelio on October 31, 2009, 03:05 PM
then i guess it's good science's journey is to head towards lighter, and stronger, as opposed to my own journey which is heavier, and weaker.


Title: Re: Sail stretch
Post by: coogee on November 01, 2009, 02:39 AM
As it happens I can supply as many blown out sails as you require for making pre stretched kites. Just send me a message and I will give you a approximate cost for said saggy baggy pre stretched gear.

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Title: Re: Sail stretch
Post by: normofthenorth on November 01, 2009, 11:05 PM
Problem with "pre-stretch" is that it's not much newer than the stuff that tears wide open. Sails have a tough life. Lots of UV, they're usually out for a LOT of hours each summer, they often spend too much time ragging or luffing, e.g. at a dock, while towing, while motoring, while slowing down or "heaving to", etc.

And some people roll them up tight and then let the roll BEND, which does a remarkably good job of destroying the finish! At least our "sticked" kites are safe from that particular abuse, thank Heaven!

The good news is that if you can find a sailor who races seriously/competitively and hardly ever social-sails "just for fun", you may be able to find a good source of not very tired coated fabric. Usually it's the spinnakers -- typically made of coated ripstop nylon, often 3/4-oz. -- that would be of most interest to a kite maker.

Me, I think I still have a smallish hand-me-down (dinghy) hand-me-down spinnaker stuffed into a bag in the basement somewhere, waiting for me to make a big NASA ParaWing out of it. It's probably been waiting a dozen years already. . .I think I got as far as peeling off the Rip-Air tape from some of the rips.