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Researcher1

Kitesurfer seeking skydivers advice

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mark

Here's something I mocked up this morning using a 3-ring release (thanks, Bill Booth) and folded-bridle pin release, like Plexus Booster (thanks Eric Fradet).

The spring is from a sewing machine table lamp. You'd need to choose a spring to give the appropriate tension at the point of release.

Mark



That is more complex than it has to be.
Very nice setup but it can be simplified.

Instead of sewing on the spring you can buy a spring like this one.
http://www.basstacklemaster.com/Bass-Pro-Shops-50-lb-Spring-Scale-p/bpsssr50.htm

Lets call the top of the scale a eye and the bottom part for hook.
When it loads the eye and hook spreads apart.

Attach the hook to the riser where you connect the links and connect the cutaway cable to the eye.

Now you have a scale that you can measure the force and "finetune it" by cutting the cutaway cable.

In this way no sewing is needed.

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Nice Mark. Clearly, you have too much time on your hands. Maybe I should have you put that lineset on my stiletto? ;)

I've showed my engineering students your solution and they are trying to build it in Inventor (3D modeling software). I'll post a pic when they finish. :)
Birdshit & Fools Productions

"Son, only two things fall from the sky."

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Bear in mind Bill's #1 requirement of any cutaway system: that it doesn't cutaway until you want it to.

What if the kite surfer is airborne when this device is subjected to force sufficient to trigger the cutaway? These guys can get up to some height and it's not always over water.

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mr2mk1g

Bear in mind Bill's #1 requirement of any cutaway system: that it doesn't cutaway until you want it to.

What if the kite surfer is airborne when this device is subjected to force sufficient to trigger the cutaway? These guys can get up to some height and it's not always over water.



I don't think the purpose is to separate the Kite from the 'pilot' - so that wont happen. I understand it to be a 'hold on a minute until I'm ready to launch' type of thing.

(.)Y(.)
Chivalry is not dead; it only sleeps for want of work to do. - Jerome K Jerome

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shropshire

***Bear in mind Bill's #1 requirement of any cutaway system: that it doesn't cutaway until you want it to.

What if the kite surfer is airborne when this device is subjected to force sufficient to trigger the cutaway? These guys can get up to some height and it's not always over water.



I don't think the purpose is to separate the Kite from the 'pilot' - so that wont happen. I understand it to be a 'hold on a minute until I'm ready to launch' type of thing.

I'm not sure we got to the bottom of exactly what the OP wanted. That's exactly what current cutaway systems on kites do though - they detach you from your suspension point attaching you to the kite. You may still be attached, but only by the brakes - hence the kite will collapse. Great if you're being dragged along the ground - not so great if it happens at 20ft.

Anything that is triggered by the force of the kite's pull independent of some input by could activate at any height. As to what it triggers... I'm not sure exactly what the OP has in mind. You only have essentially 3 lines to work with though on a kite - two control lines (essentially 25-30m "risers" made of spectra (or one of the others) type line) and a pair of brake lines which tend to terminate in a pulley system a few ft from the flyer and then attaches as a single line to you.

There are oodles of variations on that theme with vastly more complicated de-power kites where you can essentially adjust the trim of the kite independently of your load-bearing connection to the kite. That may be something he's getting at but there all you have to do is let go of the bar and it de-powers so not sure why there's a need for a mechanism.

If flying on handles rather than a bar you have 4 lines to work with as you can control the brakes independently but frankly you can easily be overpowered by the wind when caught out by a gust and loose the ability to apply brakes sufficient to control the kite. At that point, absent a cutaway system/dead man's handle of some form you're along for the ride. If that's straight up, you're in trouble.

All this applies to flexi foils only (essentially exactly the same in design as a parachute only they range from about 30 square ft to up to a little in excess of 100 square ft in size (they measure in m2). I've no idea if the OP is asking about leading edge inflatables - kite surfers tend to use those rather than foils, but foils are still used. Any land flying (buggies/boards etc) will be with foils. I can't comment on LEI's as I've only ever flown one once and can't recall what control system it had.

I think the question of what the relase system does once it's released is still to be answered. As I say though, there aren't exactly that many lines to work with and if it's to replace a traditional cutaway system on a kite... well that does exactly what it says on the tin - it releases your harness from its connection to the kite.

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Hmm - I just re-read his second post:

Quote

This line would be used to hold a kite down and need to release under a certain load on its own...not be used during riding.



What he's looking for is some fucking sand. Pile some sand on the kite - go get in the harness etc. Pull on lines and launch kite - sand falls off. Simples. Replace with weighted bags of shot if you're looking for something calibrated. Job's an orange root vegitable.

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mr2mk1g

Hmm - I just re-read his second post:

Quote

This line would be used to hold a kite down and need to release under a certain load on its own...not be used during riding.



What he's looking for is some fucking sand. Pile some sand on the kite - go get in the harness etc. Pull on lines and launch kite - sand falls off. Simples. Replace with weighted bags of shot if you're looking for something calibrated. Job's an orange root vegitable.



B|B|

(.)Y(.)
Chivalry is not dead; it only sleeps for want of work to do. - Jerome K Jerome

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