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Researcher1

Kitesurfer seeking skydivers advice

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I am a kitesurfer looking at developing a quick release safety system. In particular, I seek a device that will automatically release a rope when a load reaches ~50lbs. This device would need to detect the load (eg. spring or cam) and then release on its own. Unlike a panic shackle or quick release shackle that are manually activated... I understand you folks mainly use devices that prevent release, but I would like to pick your brain and see if you have any advice.
Thank you.

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I can envision such a device. I'm not set up for it but I don't think it would be that hard to build. It would be easier if you could tell us a little more about it's use. Do you want a release like a cutaway that will completely release it or are you looking for something like the clutch on a big fishing tackle with a break that will slip releasing line at a certain load?

Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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Hmmm gotta wonder if velcro like is on a static line pilot chute assist would be of help to this guy... The trick would be to get the pieces of velcro (IN SHEAR) the right size to provide the desired the release threshold.
The choices we make have consequences, for us & for others!

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I think I follow. The kite would be set up ready to fly. You back up to line stretch. inflate the canopy and then give it a good pop to free it?

I would think a type of spring loaded clip would do it. For purposes of wear and smooth release I think I'd put a small ring on the canopy for it to clip to. I think the clip could be spring adjustable to control the force. I could draw some thing but I can't think of an off the shelf. How many of these are you looking for? Is there a continuing market? I know some guys that just started a machining shop.

Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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GLIDEANGLE

Hmmm gotta wonder if velcro like is on a static line pilot chute assist would be of help to this guy... The trick would be to get the pieces of velcro (IN SHEAR) the right size to provide the desired the release threshold.



I don't know if you could get velcro to be predictable/reliable like that. After it's been released a couple times, it wouldn't hold as strongly, and if it gets to set for a while, it would hold too strongly.

I can't see anything other than some sort of spring scale to measure the 50#, and some sort of "trip" to release it.
Depending on the actual size/weight needed for it, a 3-ring might be a solution. I'm not sure how it would be rigged. There are other releases that might be more suitable.

To the OP - we have a 3-ring release, that is used to "cut away" a malfunctioning main canopy. It's main attributes are that it won't release by accident, it doesn't add much weight to the system and it won't load up under stress (the pull forces don't increase much no matter how much load is on the risers)
We also have automatic activation devices (AADs) that cut the closing loop on the reserve. These are computers that measure air pressure and if they sense that the system is at a low altitude and high speed, they fire a pyrotechnic cutter. They are fairly expensive, the cutters are "one shot" units and I don't think they would be applicable to your needs.

One guy who might be able to help posts here under the name "RiggerLee." See post 6. If anyone could offer a solution, I'd think he could.
"There are NO situations which do not call for a French Maid outfit." Lucky McSwervy

"~ya don't GET old by being weak & stupid!" - Airtwardo

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You're a freaking genius. That's a perfect way to do it. Or at least a buildable way.

It's kind of like the strong MARD. You've got a ring in the back of the canopy, RW-3. You've got a two ring with a RW-4 on the end of a small riser. There is a spring hooked on to the end of the riser. A coil spring with a hook on each end. The spring is hooked to the ground. There is a yellow cable hooked to the ground on the back end of the spring. When the spring extends the yellow cable pulls out of the loop at the 50 lb point or where ever you want. And the two ring is released. Any local rigger can build it for you out of any old hard ware from an old set of risers.

Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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I have no basis for this, but I am wondering about the 50lbs figure. Does this number come from somewhere? I just imagine with a kite surfer as routine more force is involved to drag an adult across waters surface. But as I said I have no basis for this assumption and might be missing the purpose of this device.

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I'm wondering if there is a break cord that might be good for this application. I don't know what strengths they come in but a break cord link might be the solution. Fewer moving parts.


Researcher1

I am a kitesurfer looking at developing a quick release safety system. In particular, I seek a device that will automatically release a rope when a load reaches ~50lbs. This device would need to detect the load (eg. spring or cam) and then release on its own. Unlike a panic shackle or quick release shackle that are manually activated... I understand you folks mainly use devices that prevent release, but I would like to pick your brain and see if you have any advice.
Thank you.

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OK, I also don't understand exactly the purpose required....

BUT, from hanggliding and glider experience. Check out these type of devices, where they also offer weak links. These guys also have links for kites, at 80daN break.

http://www.wingsandwheels.com/page30.htm
You have the right to your opinion, and I have the right to tell you how Fu***** stupid it is.
Davelepka - "This isn't an x-box, or a Chevy truck forum"
Whatever you do, don't listen to ChrisD.

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RiggerLee

You're a freaking genius. That's a perfect way to do it. Or at least a buildable way.

It's kind of like the strong MARD. You've got a ring in the back of the canopy, RW-3. You've got a two ring with a RW-4 on the end of a small riser. There is a spring hooked on to the end of the riser. A coil spring with a hook on each end. The spring is hooked to the ground. There is a yellow cable hooked to the ground on the back end of the spring. When the spring extends the yellow cable pulls out of the loop at the 50 lb point or where ever you want. And the two ring is released. Any local rigger can build it for you out of any old hard ware from an old set of risers.

Lee



I think this setup is the winner...
Simple, strong, easy to build, no parts that "break" and easy to set up.

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You might be best off giving a little explanation as to your current set up. People may be able to give some better input that way as skydiving gear and kite surfing gear are not exactly the same.

I power kite with flexi's and have no experience of flying LEI's - I've no idea what setup you have. I for a long time, have been unsatisfied with the safety devices available in power kiting. They all require user input to depower or cutaway a kite. To me that's dangerous in any situation where you're pushing the boundaries. I would prefer some kind of dead man's handle setup and went some way to developing something but then kinda moved onto other things.

To translate this to the skiving world, imagine all 4 sets of suspension lines coming to a bar, both left-hand line sets attached to the left hand end of the bar and both right-hand line sets attached to the right hand end of the bar. The brakes attach separately and are not used for steering - turns are generally what jumpers would consider to be harness turns.

You have a harness with a hook on your waist. You hook a flexible connector from the middle of the bar to the hook on your waist. Pull the bar left like on a pedal bike and the wing turns left etc.

The problem comes when you get caught by a gust or surge of power you were not expecting. To depower your kite, you must physically pull the bar towards you and un-hook yourself from the connector point. Un-hook and you ditch the suspension lines and are left holding the brakes - so the kite collapses and you're no longer being pulled about.

Of course, if you have significant force going through you this can by VERY difficult. You may be able pull on a plastic toggle attached to what is essentially a 3-ring circus (made up of a pin and two loops of cord) to detach yourself, but this still requires physical intervention and not all systems have this safety feature. Few flyers understand the need to have a hook knife.

Simply letting go on this kind of setup does nothing. You're along for the ride. Therefore, a dead-man's handle to me always seemed the way to go - maybe a leaver device forming part of the grip point on the bar which when closed, closes the connector point on say, the right hand line set, with a cross-over line connecting the line set to a ring on the brake lines so the whole line set doesn't disappear off towards the kite.

Ie, let go of the bar and whilst the bar remains connected to your hook-in point, the right hand line set lets go when the dead-mans handle is released. This slides a couple of meters up the brake lines to a stop. Kite then completely collapses as the right hand side looses all connection with you, the left hand side goes limp (to the end of the bar control range) and the brakes both come on, collapsing the wing. To re, connect, you only have to walk a couple of feet up the brake lines, find the right hand line set and hook it back into your dead-mans handle closed line connection on the right hand side of the bar. Depending on the length and where the handle is located, you could even configure this for one-handed flying.

Bear in mind the "suspension lines" are 25-30m long so you don't really want whatever system you come up with having anything to do with the canopy - it needs to be down with you at the control bar end.

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The application relates to a line to hold the kite stationary, not a release for the rider side. I will work with trying a magnet...one step forward two back...gracias for the well-thought responses. If anyone knows of any small cam/spring driven device please do jump in (pun intended). BTW killer footage of those dudes who jumped out of the 2 planes....badass...

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RiggerLee

You're a freaking genius. That's a perfect way to do it. Or at least a buildable way.

It's kind of like the strong MARD. You've got a ring in the back of the canopy, RW-3. You've got a two ring with a RW-4 on the end of a small riser. There is a spring hooked on to the end of the riser. A coil spring with a hook on each end. The spring is hooked to the ground. There is a yellow cable hooked to the ground on the back end of the spring. When the spring extends the yellow cable pulls out of the loop at the 50 lb point or where ever you want. And the two ring is released. Any local rigger can build it for you out of any old hard ware from an old set of risers.

Lee



Yeah this is a super smart way to approach it. OP prolly doesn't understand all the concepts well enough to see the whole picture though?
~D
Where troubles melt like lemon drops Away above the chimney tops That's where you'll find me.
Swooping is taking one last poke at the bear before escaping it's cave - davelepka

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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

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I'm not supper fimiller with kite technology. It sounds like all of these safety systems not only deal with an active release but involve a full collapse of the canopy. I don't know how big these canopies are or how long your cord is. I wonder if you could build a system that would automatically depower the canopy with out collapsing the canopy or disturbing it's flight. Think of it like this. If you could let out on the C, D lines and depower the back half of the canopy basically changing it's angle of attack in the event of a gust. The A, B lines actually stay at the same angle so the nose is not prone to collapsing just like on a skydiving canopy. What you're really doing is cutting the square footage down by half.

Here's what I'm thinking of. Say you had a bungy. Heavy, like the big rubber ones. It's attached to rear lines. It fas a ring on it above the bungy. The front lines are attached to another ring. It is looped around the bungy free sliding. So that it rest against the top ring under load so the canopy is in trim. Every thin flies the same till you exceed a certain amount of force. There is a lanyard attached to the bottom ring and if the bungy stretches beyond a point it will start to real in the front lines automatically reducing the lift. It would be adjustable by a friction adapter like on a small cargo strap on this lanyard. Start with the canopy depower but still flying. When you're ready to really go, push the button letting out lanyard and the max power of the kite increases. If it's windy and you're scared pull in on the end of the lanyard and the max performance goes down but until you hit the max the canopy is in perfect trim. That's the easiest way I can describe it. In practice it would be a little more complicated. The line running to all of the front lines would come into a ring on each side of the bar. It would turn and come to the center. And go through another ring. The two lines would come to a center ring joining them so that the sides stay even. This is where the lanyard would attach. The bungy would go to the center of the main bar just like your normal attachment point.

Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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That's exactly what I was thinking. Thanks for building it. I had not thought to draw it for him. But I think you could get by with a two ring. I don't think he's going to need enough force to justify a three ring.

Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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Quote

This is a very interesting setup. Never seen anything like it.
Thank you for taking the time to rig and photog this device. I need to look it over and figure out how it operates.



That's an awesome looking solution. You've got a few really smart, really experienced people helping you out here, BTW
Owned by Remi #?

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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



Yep. That's what I had in mind.

And any day that RiggerLee calls me a genius is a very good day. B|

Edit to add:

researcher1

This is a very interesting setup. Never seen anything like it.
Thank you for taking the time to rig and photog this device. I need to look it over and figure out how it operates. Smile



If you google "3 Ring Release" you can find out what it is and how it works. It's the device we use to chop a malfunctioning main canopy. All this does is use a spring to allow tension to release it rather than the handle and cables that we use.

Alternatively, go to the nearest Drop Zone (skydiving center) and ask about it. Bring a case of beer and show up at the end of the day and you will get all of your questions answered (really, you will).
"There are NO situations which do not call for a French Maid outfit." Lucky McSwervy

"~ya don't GET old by being weak & stupid!" - Airtwardo

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