Dual-Line Kite Safety

IMO 2-line kites are better off being used on a bar - I've heard you can crush bones in your hands and wrists with straps. Then simply one KK to one line and you're set that's what I do when I'm training the wife!

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Originally posted by lad I was thinking the same arrangement for a Nasawing (just hooking KKs to both brakes won't necessarily keep one of those down). You can get a cheap/used kitesurfing bungee leash on eBay. they also have their own quick release near the body attachment point (in case your kite hooks onto a passing train or low flying jet!).

Hmm, interesting to know. I'm thinking about building one, so I'd be interested to know more about NPW safeties. How well does dropping one handle work for those?

And thanks for the tip; I'll definitely be scouting eBay. I was thinking existing ones might have too long a leash, though - this only needs to be about a foot or a foot and a half long, so the cleanest way to do it would be a short leash so as not to leave more slack than I need. It'd be annoying to hook my safety system on my knee or foot or something if I end up crouching. I was also thinking that the velcro would allow you to bail from the safety if even that wasn't enough, but the quick release is even better. I'll definitely be interested to see if I can find something suitable, it'd be easier than making one from scratch.

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Originally posted by csa_deadon What I have found with dual line kites, is the typical wrist strap is extremely difficult if not impossible to get out of when it hits the fan. Maybe not the best solution, but when flying dual line, I use the padded wrist straps. A whole lots easier to get out of.

Even with big padded wrist straps, it's still going to take a little longer to get out of than letting go of a handle, which could equate to being dragged a hundred or more feet than you would have otherwise. Holding the straps in your hands rather than looping them around your wrists would be much faster to get out of - essentially converts them to soft handles.

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Originally posted by Kamikuza IMO 2-line kites are better off being used on a bar - I've heard you can crush bones in your hands and wrists with straps. Then simply one KK to one line and you're set that's what I do when I'm training the wife!

I haven't tried a bar, but I don't think I'd like it. Seems too attached, too rigid. I like the flexibility of the two unjoined lines. Maybe I'll feel differently if I start using a harness with a strop (or bar), but for now I like the feel of it the way I have it set up. It also seems to me like a bar would limit my steering ability - I tend to pull one line way back to do really tight little loops, and I haven't seen a bar long enough to pull one line that far back even if I pointed it directly at the kite. A bar that big would probably present its own problems, too. Plus handles are more of a workout.

I would certainly believe that there's a potential for hand injury with the wrist straps rather than just the injury from being dragged. Having the straps (even the padded ones I have) dig into the backs of your thumbs starts to hurt after a while, and I could definitely see how a sudden yank could cause some serious wrist/hand injuries. Holding the straps in your hands instead of looping them around your wrists alleviates that concern, and having a wrist strap to one of the two lines creates the same sort of safety as the bar.

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Originally posted by furbowski a well powered 2-line kite can take a long time to come down after dumping to a one-line safety. What can happen when going to one line as a safety measure is that the kite can remain powered up on the one line and then just spin about like a helicopter. It will come down to the ground eventually, but it does not flag out on one line as tidily as one might think. Worse, it stays powered up until it hits the ground. So I'm not a big fan of doing the one-line thing. agree on the handles, padding is a must, and yes much safer to hold on with fingers. I don't like the compression that wrist straps deliver, either.

Hmm. That's a serious hurdle to this idea, then. Could you provide some more info? Which kites have you seen do that and in what windspeed? Got any videos of it happening? I have a hard time imagining that it wouldn't just flag out and depower almost entirely (with the exception of drag from wind resistance), but I'm new to this so it's quite possible i just haven't been exposed to the sorts of gear and conditions that cause this. How much power is left when this happens? It sounds like the kite could still whack someone pretty good if it's still powered up, but could it keep dragging you? I'll try dropping a wrist strap in as many conditions as I can to see if I can get this to happen. Maybe if I know more about it I can find a way around it. If not, it'd be better to find out my safety won't work at some point before I need it...

And yeah, the compression is pretty bad. I tend to fly the kite to the edge of the window and grab the straps about an inch higher to get some relief, but they always slip back after a couple minutes. Honestly, one of the main things I hope to get out of this system would be a more comfortable way to hold the straps without worrying about losing my kite if it gets tugged out of my hands or slips for some other reason.

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Originally posted by Kamikuza If there's enough slack in the limp line, won't the kite just make like a magic carpet and just sorta flop on down? I know my stunt kites used to helicopter when they were on one line but they had a rigid frame and limited bridle ...

Yeah, I can't imagine a foil having much power once that happens. I feel like it'd just be a blanket in the wind at that point, but it's definitely worth looking into. Maybe the bridle on half the kite and the flapping opposite half is enough to keep it at least partially powered? I don't know... anyone else seen this happen? The only way I could see it happening is if something failed with the safety, like a kite killer being tied too close to a bar and not providing enough slack in the opposite line or the slack line getting caught on something after you let it go and providing enough resistance for the kite to power up again. Like I said, I'll definitely be trying to recreate this in different conditions during future flying sessions - anyone else who has ever seen anything like this, please post and let me know.



Thanks for the feedback, everyone. If I make any sort of safety system I totally intend to try it myself as much as possible before I recommend anyone else try it. Hopefully we can come up with something good; if we can prevent even a single injury I'll be happy. I'm already pretty happy that the first four replies to this thread didn't say "been tried before, didn't work, search better."

Keep the feedback coming!

For training, a bar seems much easier to get across the idea of 'push and pull' to steer ... it's also MUCH easier to keep even tension on the lines. I seriously dislike the idea of being without brakes though ... which is why the only 2 line kite I have is for training

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Originally posted by Jovver The way you solve the helicopter problem is by attaching the killer further up on the leader lines to the bar.

I thought that's the 'best' way to attach killers and everyone knew so I didn't mention it - but you're right and that's what I do

No no, fair call - I had to do a googlemf when I got my KKs in the post cos I couldn't see how to attach them the first hit with pics was the 'at the end of the handle leader' so I assumed everyone had done the same thing

If you let go of one strap you have a death spiral on your hands. This is much more dangerous than holding on. If you hold on to both straps you can atleast crash the kite and end the power. A death spiral can go on for some time and you will be getting dragged as you will be feeling almost the maximum amount of power out of your kite during this time. Plus you will have no control.

The bridals span the whole half side of the kite so the side you hold onto will be powered up. And as mentioned above some dual liners have the bridles even stretch across the center point. That is even worse. I think you may have the flagged out kite idea in your head if you have watched a peter lynn twinskin do this. But you must remember the twinskins have no bridles and the lines are connected only to the far outside of the kite so it will flag out.

I do not sell dual liners just for this purpose .. no safety. I hope you come up with something that works. It takes ideas and people willing to try new things to keep this sport progressing

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Originally posted by Jovver Warning, off-topic post! Kamikuza, how did you get the pics of the kites you fly into your signature like that?

I trawled the internet at work :D several came from powerkiteshop though ... the hardest one was the kite wing that was a 'drawing' rather than a photo ...

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Originally posted by Kamikuza For training, a bar seems much easier to get across the idea of 'push and pull' to steer ... it's also MUCH easier to keep even tension on the lines. I seriously dislike the idea of being without brakes though ... which is why the only 2 line kite I have is for training

Yeah, sorry, didn't mean to bash the bar. Just not my style. I like the "wind tug-of-war" effect too much, anyway.

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Originally posted by furbowski hiya... the helicopter thing is worse with higher winds, bigger kites, and crossover bridles (the power bridles on many smaller 2-lines don't just serve half the kite, but reach across the half-way point, thus keeping more of the kite powered when doing the helicopter) trouble is, higher winds and bigger kites is when you're more likely to want a safety. milder conditions, yes, just walk towards the kite, slack the lines a bit, and the power will ease off and the kite will fall. It's not a serious problem, I may have come on a bit heavy. skill level has a lot to do with it as well, the better you are the less likely you'll need to dump the kite. bottom line with the safety: be as aware of all the things that can go wrong, and do as much as you can to understand and / or reduce the risk. You can't completely take risk out of the equation and continue to have fun kiting, not really, it's something to be aware of and live with. But you can reduce it a lot by taking time to go through what can go wrong. just had a look for videos, I've seen a couple but couldn't find them again! hope all that helps a bit...

Good to know. Thanks for all the extra info. Is this the sort of thing where it's pretty easy to see if a particular kite will do this? Like, if I take my kite out and let one line go and it doesn't helicopter, can I assume it will continue to do this in the future? Or if it does helicopter, can I assume it will continue to do that in the future? If so, we could recommend people test their kite that way before they rely on this sort of safety, but if it's more unpredictable than that it could still be trouble.

I sort of disagree about skill level meaning you're less likely to dump the kite. That could be, but I haven't had to dump mine because I'm not terribly experienced yet so I haven't taken many risks with it. When I get better and have more kites, my 2.5m will be my go-to kite in high winds when anything larger would throw me over the nearest building. I'd say I'm much more likely to have to dump the kite in those winds than I am in the 5-10mph winds I learned to fly in. I do see your point, though - ideally you shouldn't be putting yourself in a situation where you would need to dump the kite, and more skill will let you recognize those situations.

And you're totally right about the risks. Definitely going for risk reduction here rather than complete elimination of the risk. Then again, if it doesn't require safety gear, why am I doing it? I'd definitely feel better handing this kite off to my friends with some sort of safety system, though.

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Originally posted by fulhamatt I toyed with the idea of learning with a 2 line (Being used to the feel of stunt kites), however, now that i'm (Slowly) getting used to using the brakes to turn and take the power away from the kite, I couldn't imagine feeling so out of control - I mean, you wouldn't knowingly drive a powerful car (or any car for that matter) with no brake pedal. So why risk it with a kite?

Well, a car without brakes won't stop when it gets to the edge of the road. My kite will stop when it gets to the edge of the wind window. Regardless, there are a lot of dual-line kites out there, so we might as well come up with a good safety system for them.

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Originally posted by DAKITEZ If you let go of one strap you have a death spiral on your hands. This is much more dangerous than holding on. If you hold on to both straps you can atleast crash the kite and end the power. A death spiral can go on for some time and you will be getting dragged as you will be feeling almost the maximum amount of power out of your kite during this time. Plus you will have no control. The bridals span the whole half side of the kite so the side you hold onto will be powered up. And as mentioned above some dual liners have the bridles even stretch across the center point. That is even worse. I think you may have the flagged out kite idea in your head if you have watched a peter lynn twinskin do this. But you must remember the twinskins have no bridles and the lines are connected only to the far outside of the kite so it will flag out.

Hmm. I think if you're going to need a safety, it's going to be in the sort of situation where you can't steer the kite even to crash it or get it to the edge of the wind window. In a situation where I'm getting dragged face-first though grass, dirt, sand and small rocks I would have some serious doubts about my ability to even steer the kite enough to crash it. Letting go of handles is something I feel confident in my ability to do in any situation.

And no, I didn't get the impression that it would flag out from Twinskins. I could see how a bridle-less kite would do it better than any other kite design, but I got that impression from my kite, which seems to depower pretty well on one line. You guys definitely have me reconsidering that assumption, though, so I'll absolutely be trying to get it to helicopter the next time I go out. I'll report back once I do, but I might not get strong enough winds to properly test it for a while.

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Originally posted by Drewculous Run a third line that only attatches to the very outside of the kite, or the very farthest bridals, you let go of the handles, kite goes all twin-skin on ya and the terror ends :tumble: or just get a 4-line :smug:

True. I was hoping there'd be some way to make a dual-line kite safety rather than just adding more lines. I could buy some handles and lines to convert my Stylus to a quad-line, but I was really looking for a way to make everyone's dual-liners safer rather than just mine. Besides, I've heard the Stylus doesn't fly as cleanly as a quad-liner, so it'd be worth looking into dual-line safeties for the sake of kites with a two-line bias.



Thanks again to everyone for the feedback. I'll definitely be doing some testing with my kite next session to see whether or not it has a tendency to helicopter, and after that I'll hopefully be buying some kite killers and rigging up a safety system.

It seems like there are two types of leashes, though, bungee and just a normal cord. Is there an advantage to having an elastic or non-elastic leash? Seems like the bungee leashes advertise that they won't yank on your wrist and the the corded ones say they won't snap back like a bungee in the event of a break, but which is actually better?

One idea I had is to use a device similar to those spring loaded dog leash winders [see image below]... you would attach the winding device to your person and run the leash end to one of the kite handles. This way, you can drop both handles in an emergency and the winder will allow the kite to drift with the wind until it hits the ground.

Obvious issues I forsee with this:
- The winder is potentially not strong enough to hold the kite when the line is completely drawn out; the winder may break, releasing the line and your kite.
- The line in the winder is potentially not long enough to allow the kite to hit the ground fully depowered. If scenario #1 is not true, this will allow for the possibility of you being dragged by the winder (although unlikely I think).
- The winder WILL put a small amount of tension on the leash line, which will in turn put a small amount of tension on the kite handle. There is a possibility that this will keep the kite powered, but I've done no testing with this rig yet to determine whether or not this is a major concern.

Can anyone build on this idea? This is the best thing I've come up with, aside from using some sort of ground anchor point which would inhibit your mobility and create a lot of line mess.

Here's the kind of leash I'm talking about... you can push one of the yellow buttons to stop the leash from unwinding, but in my example you would just let the line run until the kite was on the ground. You would attach the metal hook point at the end of the leash to one of your kite handles so that even if the line in the winder isn't long enough, it's still only going to pull on one side of the kite and that [hopefully] isn't enough power to continue to drag you.

here's the video I was looking for wayyyyyy earlier in this thread re: what can happen when one line breaks and the kite does a powered spiral on its way down. This is a four line: but can happen with the bigger two-line kites in a decent wind. she seems to have lost one handle but also seems determined to hang on to the other, not sure why...!!????

http://www.youtube.com/watch?v=L3_TDZUO2QA&feature=relat...

scudley posted it in this thread, that's how i found it again! thanks, scud!
(scroll to the bottom)


http://www.powerkiteforum.com/viewthread.php?tid=10329&p...

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Originally posted by kitejumper its cool that youre exploring new safety ideas for a 2 liner--when starting out, a 4 line kite SEEMS alot more complex and alot less safe.....well,its not true at all--4liners are the way to go---i got overpowered by a 2 liner last winter and i was able to let go,if not , i would hate to think where i would be today--probably in a wheelchair---dont resist the 4line frenzy--its the way to go-u wont regret it........::singing:

It really isn't that I'm resisting getting a quad-line, it's that I'd also like my dual-line to have a safety. I'm actually in the process of getting myself a quad-line, but I still want a safety on my dual-line, especially for handing it off to friends. There's also a good chance my girlfriend will be using this kite frequently, and it'll be the kite I use when the wind picks up and flying the larger quad-line I'm getting isn't a smart idea. I definitely want a safety on it in those situations. People keep telling me to get a quad-line - that's a perfectly valid alternative, but there are still plenty of valid reasons to come up with a working dual-line kite safety. This thread is about making dual-line kites safer, so let's keep working on that end of it rather than saying people should stay away from them. At the end of the day, people are still going to fly dual-line foils; wouldn't you rather they be safer?

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Originally posted by furbowski here's the video I was looking for wayyyyyy earlier in this thread re: what can happen when one line breaks and the kite does a powered spiral on its way down. This is a four line: but can happen with the bigger two-line kites in a decent wind. she seems to have lost one handle but also seems determined to hang on to the other, not sure why...!!????

:shocked2: Looks like she was wearing a helmet, at least... As for why she was holding on, could very well be that the lines on one side broke free and she was still hooked in with a kite killer to the other wrist - exactly the problem we're worried about here. As a side note, that's an interesting discussion in that other thread about whether or not to use kite killers. Some food for thought, certainly.

I did manage to get out to the field today and do some testing with my Stylus. Winds were very light so it was difficult to get a good idea of what it would do in higher winds, but I got some decent testing in during some of the windier moments. Going back to the lumpy inland winds really makes me miss all that smooth wind at the beach last week.

Most of the time I let the kite go it flagged out and fell to the ground. It wasn't necessarily instant, but when this happened it definitely depowered to the point that a fully powered plastic shopping bag on the end of the line would have had a better chance of hurting me.

Running backward to increase apparent wind, I found that if I set it up just right I could get the kite to helicopter. Exactly like you said, half the kite remains powered while the other half flaps around, and it spins around pretty badly. It's not as bad as it could be, though - since only half the kite is powered up, the pull drops drastically. I'm not sure that the pull drops off enough to make it really a "safety," though. This definitely needs more testing in higher wind.

There is a light at the end of the tunnel concerning the helicopter issue, though. I found that if one line was released rapidly enough, released during certain turns or if the line that was still connected was tugged as the other was released, the shock of that motion could upset the kite's balance enough to cause it to collapse altogether and flag out. This might be the key to a proper safety system.

I'm still thinking along the same lines here as in my original post - a kite killer with a bungee leash might give the kite enough of a yank to collapse it. Whether or not this could be recreated reliably enough for use as a safety has yet to be seen. It could require a more elastic leash to let the kite out a little farther and yank it back a little harder. My concern would be that, with the kite in really strong wind, the wind could provide more force keeping the kite open and inflated than the bungee cord could provide to pull it out of the air.

This definitely needs more testing in stronger winds. I'm going to pick up some kite killers to test with and see if that changes the way the kite behaves when I let it go. If anyone else wants to see how their dual-line foil behaves on one line, definitely go out and do it and let me know how it goes. I'm still hoping there's a solution out there that works for most dual-line kites, so more information is always good.

I don't know if I've said it before, but thanks to everyone for all the input - every post generates ideas, and every idea helps! :roll: