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How much tension really is on the lines?

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purdyd
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Re: How much tension really is on the lines?

Postby purdyd » Thu Feb 07, 2019 2:43 pm

That is a good find. It looks like the green is the main lines and red blue are the back lines.

A decade ago I did spend a lot of time pulling things through the water at high speed and measuring the tension on a line.

A wakeboarder took 150 lbs force to get them out of the water and 75 lbs force on average to keep them going on plane. If the units in the screen grab above are daN then that seems about right for edging and doing some tricks.

Probably can do some estimation on forces on jumps from the weight and aceceleration of the rider looking at videos.

If you are unhooked, there are definite limitations to how much force is involved on the lines.

We did break some spectra line at less than then rated load due to impact loading. In those cases a stretchier line was better.

You would have to look at the relative areas under the stress strain curve for the kite lines not just the rated strength for impact loading. There seems to be a real dirth of data in this area.

I have posited that if things really went bad, it might not be bad for your kite lines or something to break.

Based on the fact I don’t see kite lines breaking all the time and my experience measuring some similar things, I think kite lines are probably about right.

Of course wear and uv damage certainly can change that.

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Re: How much tension really is on the lines?

Postby edt » Thu Feb 07, 2019 3:15 pm

Nice. I don't remember watching mutiny do that test before.

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Re: How much tension really is on the lines?

Postby mrbig » Fri Feb 08, 2019 10:52 am

kite_hh wrote:
Thu Feb 07, 2019 12:47 pm
Great! This seems to confirm the values dimensions of the other video.

Screenshot_20190207-124449.png
Green line probably is the combined tension on the power lines and the lower two lines are the measurements on the steering lines.

I wish they would make the data publicly available.

About 2 weeks ago in Langebaan (Cape Town) I saw a guy testing a whole bunch of kites (different makes) with the above kit.
All the kites were flown off the same set of lines and bar and he was looping the kites fairly aggressively on the beach - it was a light wind day.

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Re: How much tension really is on the lines?

Postby evan » Fri Feb 08, 2019 11:09 am

Is that how duotone is trying to justify their crappy lines, by showing that the loads don't exceed the factory breaking load?

I am now racing with a 25*4mm stainless ring that deformed in my testing bench above 200DaN. As it is still perfectly round after a few sessions it is safe to say that powered foiling + jumping don't exceed that load on the power lines.
Also tested some plastic chickloops that broke already at 300DaN. Those things are sold with many people riding them.

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Re: How much tension really is on the lines?

Postby Hugh2 » Sat Feb 09, 2019 7:16 am

They should have had a meter on the lines during this testing.

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Re: How much tension really is on the lines?

Postby sarc » Mon Feb 11, 2019 10:53 am

kite_hh wrote:
Thu Feb 07, 2019 12:47 pm
Great! This seems to confirm the values dimensions of the other video.

Screenshot_20190207-124449.png
Green line probably is the combined tension on the power lines and the lower two lines are the measurements on the steering lines.

I wish they would make the data publicly available.
I would guess red = left back, blue = front back, green = center front. Just a guess


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