Kitebuilder Online

Dennist3 · Posted: Wed Apr 14, 2004 7:25 pm Post subject:

Pre-streching?

I thought that Spectra didn't strech?!?

Dennis

Spence602 · Joined: 16 Sep 2003 Posts: 235 Location: USA TX Houston

knotronda · Posted: Thu Apr 15, 2004 1:39 am Post subject:

Spectra doesn't stretch once you get the manufactoring slack out of the line. Do I dare say I worked in a kite shop for almost five years? Many afternoons were spent alongside the building running lines down the side street and giving instructions on sleeving and equalizing 'stunt' kite lines. I did a pretty good job even if I have to say so myself!

Yes, the figure of eight knot is the one to use when tying your loops.

FYI, I did a lot of sport kite flying in my earlier days of kiting. I also got bit by the fighter kite bug. Two years ago, I flew a 6' Flexifoil in the Seniors Ballet at WSIKF. At least one judge admitted he gave me extra 'GUTS' points for getting out there with that kite. I had borrowed it from a friend and his lines were at least 150' long. Luckily, the announcer put on 'Fields of Gold' and I managed not to crash during the routine. When I left the field there were two women sitting by the exit and they were very complimentary about my performance. I didn't have the heart to tell them I was flying just to get in as many senior events as I could for my first year of qualifying as a senior.

Oh well, I've rambled on long enough. Spence, your description of how to sleeve and set up equal length sport kite lines is very well written.

gotta go,
knot(tier)ronda

Those were the days before I became a kite builder. I really enjoy the single line kites now.

Dennist3 · Posted: Thu Apr 15, 2004 4:27 am Post subject:

thanks KR...I had no Idea......that there was manufacturer slack in lines....

even less that you could fit in to anything "senior".....
Dennis

knotronda · Posted: Thu Apr 15, 2004 4:56 pm Post subject:

Well, the senior age at WSIKF is a pretty low number as far as a senior age is concerned. At least that is how I feel about it as I get closer to what most companies call 'senior'. Again, my motto is "I may eventually look my age, but I'll be darned if I act it!"

KR

Dennist3 · Posted: Wed Apr 21, 2004 7:03 pm Post subject:

knotronda · Posted: Wed Apr 21, 2004 11:27 pm Post subject:

Hmmmm, some days I feel pretty old. But, once you get moving, you just don't think about it. Very Happy

Watch out for me on the rokkaku field. I am usually the shortest person out there so I have twice as many steps to run.

Oops, I think this could be a hi-jack of the thread so let's get back to sport Kite Line set up. Wink

knot(tier)ronda

marty · Joined: 22 Jan 2004 Posts: 88 Location: Arlington, MA USA

Actually, Spectra does stretch. All materials stretch.

Additionally Spectra creeps.

Stretch is usually defined as lengthening that actually restores after time. It's like pulling on a rubber band. The material elongates and when the tension is removed, it comes back to the same length.

Spectra will stretch anywhere from around 3 to 5 percent.

If you keep applying tension to Spectra it will deform so that when you remove the tension it won't return to it's original length. This is called creep.

The amount creep is dependant on the tension you put on the Spectra and the length of time that you place it there..

So, when you first set up your lines, they will lengthen until they take a set. This change in length can be very noticeable. The easiest way to see this in action is to replace one of your lines in a lineset. Even if you give a good pulling on to initially set things you will notice on the first couple of sessions that the line will continue to lengthen.

After this initial period the lines will appear to be the same length but are actually slowly creeping and getting longer. You don't notice this since the lines will change length at the same rate and the change is very small.
_________________
Gentle breezes...

Marty Sasaki
Arlington, MA USA

CJQ · Posted: Thu Apr 22, 2004 6:47 am Post subject: Spectra elongation

Hi Marty , Very good tech info. Does the weaving cause the elongathing or are the fibres streching? does humidity have an effect? If you replace a line from the same spool will they become equal in a reasonable amount of time or is it best to just chuck the pair away and start new?
Not a stunt flyer ,but just want the knowledge.

Thanks
CLIFF

marty · Joined: 22 Jan 2004 Posts: 88 Location: Arlington, MA USA

The initial stretching that everyone talks about is mostly due to the braid and the spinning of the fibers together to make that the threads which are then braided.

Creep is due to the elongation of the fibers.

Most of the time when you it comes time to replace a line, you replace a line set so that the wear, etc., on the pair (or 4 lines) is equal. Fortunately line breaks usually happen hear the ends of the lines so you can shorten both up and keep on using the set if one of them breaks.
_________________
Gentle breezes...

Marty Sasaki
Arlington, MA USA