Power Kite Forum

Kite string weights, and lengths

Michael Gaylan - 3-6-2013 at 07:39 AM

This may have been asked, but I haven't found it yet.

What are the 'typical' lengths, and weights of kite lines? I am sure it can be measured in grams or ounces.

For example: If I have a 30 meter line what should the tensile strength be (100, 150, 200 lb...) and what should the weight be for kites under say 5m?

I recall having laid a kite in water at JIBE and of course I found it to be difficult to raise when the kite was wet. (duh) I know the water adds a considerable amount of weight, but so does the lines. My question is helping me to understand the weights of the lines not so much the water logged kites.

I also know this may be a newbie question, but the only dumb question is the one not asked.

thanks

PHREERIDER - 3-6-2013 at 07:57 AM

kite LINES have several elements to consider.

length- most somewhere between 10m-25m it related to sail response. long and slow, short and quick.
drag - too heavy slows things down, to light fracture will occur.

strength- relates to application . small sail smaller lines. load to be transferred?

proper matching can be done by comparison and application or just knowledge of what is available.

front lines tend to be slightly heavier then rear. think conservation for drag and minimum threshold for strength.

like 150# front and 100-80# for rear around 20m in length.

knowledge of comparable size gear with tech notes is a easy source to match up what will give ideal performance.

indigo_wolf - 3-6-2013 at 09:43 AM

Quote: Originally posted by Michael Gaylan  
This may have been asked, but I haven't found it yet.

What are the 'typical' lengths, and weights of kite lines? I am sure it can be measured in grams or ounces.

For example: If I have a 30 meter line what should the tensile strength be (100, 150, 200 lb...) and what should the weight be for kites under say 5m?

I recall having laid a kite in water at JIBE and of course I found it to be difficult to raise when the kite was wet. (duh) I know the water adds a considerable amount of weight, but so does the lines. My question is helping me to understand the weights of the lines not so much the water logged kites.

I also know this may be a newbie question, but the only dumb question is the one not asked.

thanks


You seem to be asking two things.

  1. Static weight for a given length of kite line with a given weight/break strength.
  2. Suitable lengths and weights for a given size kite.

Am I interpreting that correctly from your first post?

Might want to clarify.

ATB,
Sam

bigE123 - 3-6-2013 at 11:34 PM

Okay here is my take on this:
Line length is usually 20m - 30m the shorter the lines the smaller the effective window becomes. Go bigger than 30m the window is much bigger and the kite response slows down.

Line strength is in kg, and the strength you require is down to your flying requirements and body weight. For static you can use a lighter line but still needs to be rated above your body weight. Once you use it for traction then you should be using higher strength lines especially if your jumping.

Lines for different sizes: I use the same strength on all my kites, because as the wind increases I use a smaller kite but it's creating the same power as my bigger kite in a weaker wind.

Once a kite is wet obviously the weight makes a big difference, but line weight is really a compromise. Go light less drag but more likely to stretch / break if they are under weight. I prefer to have use 180kg as a minimum and usually 250kg. I weigh 90 kg so I reckon with my buggy, I'm probably 120 kg so I've got lines to deal with the weight and some, in case I get lofted :D

Michael Gaylan - 4-6-2013 at 06:56 AM

@ Phreerider,

Yes, I can better understand the elements of lines now with your input. It is helpful to know terms. Again I am an dumb to most but learn well, and I ask a lot of questions before I do something stupid. So giving the response, I need a better understanding on lengths for sizes of kites now and 'strength' for the lines.

@ Indigo_wolf,

I should have clarified my question, forgive me. Yes I am asking two questions and those are the best put the way you asked them. Thanks Sam.

@ bigE123,

My 3.5 came with lines but the guy I bought them from didn't know the lengths or strength. They are measured in meters which is not a problem to do the math. How does one determine the strength/weight of a line if it is unknown? (besides actually breaking them)

I am very interested in jumping just because it's crazy! And I am an adrenalin junky from hell so to speak, once I get the hang of something I'll push the envelope to see what I can muster/master and even tolerate. lol

So now with the weight of the person, as I understand it in your post. If I am 170-180lb my kite line "strength" should be 180+ and the rear lines "could be" 100-150 or something like that. Is that a good summation? My board is about 35-40 lb.

Although the best window of the kite is about 30 meter, let's say for my a 3.5 ballistic should it be shorter? And should I maintain 2 lines, one for stunts and one for just cruising? I also understand from the posts that anything 30+ is much less responsive.

Have I have interpreted the information correctly?

Thanks for the input...

bigkid - 4-6-2013 at 07:34 AM

Not at all an easy answer in regards to lines, strength, length and so on.
Each manufacturer has their own standards and testing, they can, and do, label the lines they make from way under rated to way over rated. 7 different sets of 25m, 400/200, are not at all equal. And in some cases are not even close. I have had 20m 400/200 lines that broke on the power and brakes before the kite ever got to the zenith on a day when you could blow harder than the wind was, and then had the same size and length in a set that measured 1/8 thick on the power.
And as for someones personal recommendation of what are the best lines, it is a crap shoot because the lot number and that particular batch of line is not the same as the one you get now. Whether they are yellow, pink, blue, red, white, orange, flat, round, shiny, dull, sewn, or tied with a knot, spin the wheel and see what happens.

The best line set out there is the one you have that has not broke. I have a few that have hundred if not thousands of hours on and are still in new shape. Others are brand new and are used as a reminder of how much the good sets cost and still break.

Michael Gaylan - 4-6-2013 at 09:00 AM

Jeff,

I think I recall you mentioning this at JIBE. Lines are not at all what they appear or are rated at.

I still need to know what (approximate) lines I should use on a 3.5 meter with weight approx 200-250 lbs. It just seems odd and a "crap shoot" as you mention that lines could break like that. But I know you said they can. I have no reason not to believe that either..

I was looking at some line that is made of Kevlar. Is this what the normal kite lines are made of? Another thing that strikes me oddly in the mathematics of it all. Is if you have a 200lb lines, then shouldn't the over all weight capacity "theoretically" be about 400lb? Although I understand it not to be so, it just seems like the weight would be distributed to the lines about equally. So while in theory it may be true, reality can produce different facts.

thanks for the information...

bigE123 - 4-6-2013 at 11:58 PM

Michael, must admit I'm a little surprised by the "crap shoot" too, but that's what a forum is all about different views. In my experience I've not had a problem with lines breaking, stretching yes but that was because I got a kite stuck in a tree and had to pull a line at a time to get the kite back.

My advice based on fixed bridle kite would be two fold:
1: Don't try and skimp on lines, the cheap stuff is just that cheap 'n' nasty.
2: Stick to the branded stuff, Ozone, Flexifoil etc.

As I said before, I go for 250 kg lines, which as you rightly suggested would give 500 kg capacity over the two lines, but all things are not equal, if you leave go of one side there will be a sudden load transfer to the other. Also if you drop your handles the load will transfer to the brake lines and they to will have a sudden load transfer.

It's not about the size of the kite but what you do with it!! (Have I heard that somewhere before? :D ) For a bit of recreational flying you'll be fine with lighter lines. But if you want to use it in higher winds for traction then you need a higher rated line.

If you look at any kite that has the ability for lift (i.e. a Blade) you'll see the line strength is greater (@200 kg) and they often offer "extreme lines" @250kg.

Michael Gaylan - 5-6-2013 at 05:35 AM

Thanks bigE123.

All the information is very useful, and adds to my knowledge bank.

""It's not about the size of the kite but what you do with it!""

Yea.. I think I've heard that before too.

ROFL

cheers