Sliders and pulleys vs Rings - Safety Tip

[Hansen Design]

Hi Dimitri:
Been out testing kites all day so returning late to this discussion. I'll respectfully decline personally testing the 'O' rings the way you used them since my engineering background and experience tells me it is a poorly designed system and unacceptable for an expensive product with which people may potentially kill themselves. Your spectacular riding and death-defying stunts with kites is truly fun to watch. As a well-known risk-taker, you can use them that way - fine. My only thought is that you seem OK to transfer that risk to others and then defend that transfer by attacking anyone that questions it by claiming everything wears as a justification. Attack the messenger when you don't like the message - right?

The point is, some systems wear faster than others and since line wear is a concern, a system that causes accelerated line wear is a problem. Why do you think the demand for sliders on your website has been so strong? You've switched to sliders - GOOD FOR YOU! I've already said your passion for the sport and your brand is commendable. Why not leave it at that? Have fun in the Caymans - sounds like a good time - hope you can get back on the water. All good!
Cheers!

PS:
BTW, I did a bit of skydiving and I do not remember my parachute's risers passing through any 'O' rings in such a way that 100% of the load was on a single small line running back and forth repeatedly. As a guide for lightly loaded steering lines to keep them from getting tangled maybe, but nothing that I was hanging from. All that 'stuff' was highly engineered mil-spec custom hardware.
Cheers again!

I am sorry Mr. Hansen you see it that way, but I have been kiting on these "O"Rings for a long time. Maybe it is time for you to get in the water and start kiting so you can really do the testing on the "O"Ring.
Pulleys or "O" Rings do wear the lines after putting lots of ours kiting and I am not going to lie to you, everything wears after a lot of abuse. Same thing applies to the lines that goes through the hole of the bar. It is called WEARING.....
Also the thicker the line is the longer your lines will last. I have use both of these items and I have seen what they do. So again Mr. Hansen it is time for you to move out of your computer and get in the water so you can do a real test. I am going to the Cayman Islands next week for a photo shoot, hopefully I can start kiting again after my injury. So maybe you can join me and finally go kiting and test these items.
You know my number.

[LastChance813]

Dimitri M wrote:
And the reason they are better then "O" rings is because they look better and are more sexy then the "O" rings.

Bill Hansen wrote:
Wow! Not to mention they are far safer because they don't shred your lines!

I am sorry Mr. Hansen you see it that way, but I have been kiting on these "O"Rings for a long time. Maybe it is time for you to get in the water and start kiting so you can really do the testing on the "O"Ring.
Pulleys or "O" Rings do wear the lines after putting lots of ours kiting and I am not going to lie to you, everything wears after a lot of abuse. Same thing applies to the lines that goes through the hole of the bar. It is called WEARING.....
Also the thicker the line is the longer your lines will last. I have use both of these items and I have seen what they do. So again Mr. Hansen it is time for you to move out of your computer and get in the water so you can do a real test. I am going to the Cayman Islands next week for a photo shoot, hopefully I can start kiting again after my injury. So maybe you can join me and finally go kiting and test these items.
You know my number.

This has been a great thread, both informative and very entertaining with all the back and forth!
Dimitri,
Since you use the rings, sliders, and pulleys and you have developed or at least use and trust these different systems on your kites I would hope you have done testing on these components to find their ultimate strength. It would be helpful for the people who are concerned with the ultimate tensile strength of the different components (rings, sliders, pulleys) to decide what is best for them, so why not just post the data from your testing and shut these guys up about your rings, sliders, and pulleys?

[ronnie]

It is a good thread and thanks to Bill for starting it and Dimitri for producing cost effective sliders.

Seems to me that sliders are the way to go unless the part is sliding a lot on a bridle line, then maybe the Orbit type pulley where the connecting line goes through the hub of the pulley is the better choice. With the Orbit pulley, if the pulley breaks, then you are still connected by the line through the hub. There is still a possibility that the Orbit pully could jam and wear a line faster than a slider, so its still a bit of a guessing game.

So I see sliders and pulleys a bit like Cabrinha - where they use the slider on the part of the bridle which only moves much when the IDS is used and they use pulleys for the normal kite flying movement.
The sliders would be my choice for the powerline eg. on something like the new Zeeko system.

[Dimitri M]

Guys,
Once again I have been using PULLEYS, "O"RINGS and they all work great. And of course you will get some wearing on the lines after a while. It happens to all of them. Same thing with the CL lines going through the hole of the bar. They do get worn after after a while. Same thing with my flying lines. After using them 30 times, I start paying attention to them and see if I can find any wearing on them so I can change them, just for safety reasons.
Now the reason I am using the "EPIC SLIDER METAL RING" is because by doing so, I can hopefully keep every body happy. Some people did not like the PULLEYS and like the "O" RINGS, and other did not like the "O"RINGS but like the PULLEYS. So by combining these into one system, then hopefully every body is happy.


P.S. Bill Hansen when I say testing the kites, I mean in the water and not on the beach or on a field.

[tomatkins]

...So I see sliders and pulleys a bit like Cabrinha - where they use the slider on the part of the bridle which only moves much when the IDS is used and they use pulleys for the normal kite flying movement.
The sliders would be my choice for the powerline eg. on something like the new Zeeko system.

Excellent observtions, and comment. I also remember the thread where a Cab rep stated that justification for the use of both pulleys and "guides" on different locations of the bridle, and wondered at the time... what kind of testing did they do to come to the conclusion that pulleys need to be used on the part of the bridle that is subjected to the most motion. I wonder if they went to the trouble of rigging up a "stress-to-failure-test' device, to determine the number of back-and-forth "guide" sliding cycles before "failure" (catestrophic weakening of the bridle line)? I would imagine the test machine would be designed to drag a "slider" back and forth under pressure...working day and night until the line got significantly "frayed". Not hard to make such a test machine...just a bicycle wheel, with an off-set peg, and a rope, driven by a reduction-geared motor... The tests would be done with dry, wet and sandy line, and data would be recorded for each variety of bridle line. We have all seen the test devices that slam car doors, etc.

Also, you mentioned the Zeeko system... that is the reason I want to get some sliders. As the briliant KiteForum member, "Faklord", showed us... the Zeeko system works, only because of the appropriate amount of "friction" or "sticktion", balancing the underlying instability of the system. (Thankyou, again, Faklord, for hanging in there like a Bulldog!! and thank you "ceramic, low-friction, racebearings"). Read the Zeeko thread, if you want to know what I am referring to...

Anyway, I want to use the sliders on the Zeeko "infinitely adjustable" power line adjuster device to determine whether or not, these sliders, by any chance, have such a low coefficient of friction, that the system will not function. I doubt it, but wouldn't that be interesting, if that were the case?

Maybe you can dig up the thread, where the Cab rep made that comment. This would be a good place to discuss that subject. Maybe they will comment on their testing.

[Caesar]

Maybe you can dig up the thread, where the Cab rep made that comment. This would be a good place to discuss that subject. Maybe they will comment on their testing.

viewtopic.php?f=1&t=2370920&p=733255#p733255

Cheers
Caesar

[tomatkins]

Maybe you can dig up the thread, where the Cab rep made that comment. This would be a good place to discuss that subject. Maybe they will comment on their testing.

viewtopic.php?f=1&t=2370920&p=733255#p733255

Cheers
Caesar

Thanks Caesar,

Good grief! This whole discussion has already taken place... this thread just "reinvented the wheel"...

Here is what "Cab Driver" (I would guess he is a Cab rep or dealer?... he seems very knowledgeable about Cab products) said:

"This bridle was only meant for actual pulleys, and not silders, on every section of the bridle except for where we use "bridle guides" (the metal fixed blocks) on the front pigtail of the bridle. You are at your own risk if you use a bridle guide on another section of the bridle where an actual pulley normally distributes the load.

Good Luck!"

Plus, that thread shows a picture of the "stress test" device I referred to:

[tkettlepoint]

Yes Dimitri is a good kiter
yes dimitri is a extreme kiter
yes dimitri is a great promoter for his brand

No he did not invent the slider, he posted the guy that owns the factory that makes his kites did. So that factory make alot of different brands. SO it is not a EPIC slide like he says. In China there is no copy write laws so they will make it for anyone and put anyones name on it.

Bill knows what he is talking about when it comes to safety , I got a Switch Element mid Dec and it has these sliders on it. hmmmmm why does it have EPIC Sliders? Because they are not epic sliders they are made from a out side source for everyone to buy. I like them alot and Yes I think they will do less wear on the lines. The SS O rings are only as safe as the guy or machine welding them, and the second thing is a 1/8" ring surface area is alot less then a 1/4" slider. If you go out in 25knots on a 14m the pull power on that 1/8" ring will have a cutting effect on the line more then twice as face as the 1/4" slider...

And for testing kite Dimitri, Bill is like anyone else they test kites in alot of different conditions all over the world... From water to dirt to snow and anything in between.. Just the same as you buy sending prototypes to people around the world to test and send back to you with their thoughts.

And yes I am a team rider for Switch
Terrie.

PS Dimitri hope you can kite soon and enjoy your photo shoot

[Hansen Design]

Hi Tom:
I made that illustration for a line supplier when we were having problems with their loosely-woven 'spectra' submitted for use in a transfer line bridle system with a high quality pulley. This is how an engineer (or in my case applied physicist) approaches the problem. The 5kg load was suggested to simulate the bar pressure but the same device can be used to test sliders or rings and any type of line at higher loads.

The cool thing about the test station (at least to me) is that it can work all day long, needs no wind or water, is independent of rider skill or daring (Bill vs Dimitri) and can simulate 10 years of kiting in a day or so leaving me free to do other things like test kites, clean out the garage or play golf.

Plus, that thread shows a picture of the "stress test" device I referred to:

Transfer-Line1a.jpg (46.95 KiB) Viewed 1030 times

Transfer Line Test Station1a.jpg (22.61 KiB) Viewed 1030 times

[Laughingman]

Hi Bill, thank you for all your input. It is people like you that honestly share information which inspires others to challenge the limits of their own understanding

I am no Engineer, or Physicist but sometimes I do perform rocket surgery...
As you stated, this test was designed for bar pressure, don't you think 5kg is a bit light for testing power-line bridle wear?
I'm totally guessing here but I would assume the power-lines accept about 90 percent of the riders weight/resistance. That would mean, imho that the testing weight should be 75kg or based on the configuration at least half of that in order to come to an average wear situation. What do you think?

Sincerely

Pete