bulk line

[foilholio]

Thanks for the PM

Yes it will change how it flys (slightly), but most C kites use V. You could always shorten the lines a bit to compensate for the longer V, you like loops? shorter lines are easier/better, but then the Y gives tighter turns. You'll get more power from a V but wider turns. Also add that tensioned fifths and longer V are different in that the V just changes the arc of the kite to be wider or tighter, where as the fifth can move the depower towpoint as well. I am sure someone has swapped a regular V bar onto a torch and can report what it is like.

[edt]

As far as V vs Y, that would open the canopy up differently, not sure it would work well for the Torch as the kite is very sensitive to canopy shape.

I think the Vegas is the same way. I would ride both the naish & vegas on the high Y. It's simple enough to double the power of the Y line just run a double line instead of a single. it will have just as much drag as the V configuration in 5th line mode. It's sloppy tho running two lines, so I would do what dracop is doing, except I would probably go straight to 3mm line. Remember this is a 5 line bar so you don't have to worry about the doubled line having to fit through the safety the 5th line does that.

[dracop]

THanks for the thoughts guys.

I considered running a double line and just tying them together. Then I came across Wunderline (eg, DC-401) and figured why bother when I can just buy that. I would have to buy new line material no matter what anyways. I placed my order at this point and am awaiting shipment.

I looked at the following solutions (and attached are my notes/logic for my decision making):

Amsteel 7/64" - 2.5mm thick, thickness creates drag on performance, strong stuff at 725 kg (1600 lb) breaking strength. Supposedly Amsteel is abit stretchy altho I dont know from experience and elasticity is partially a function of breaking/avg strength, so I doubt I would be stretching it much since I would be such a weak load for this type of line. I would have bought it just for the lower 11m section. Easy to get in USA. Too thick to sue for complete center flying lines although I could have combined a lower line of Amsteel on the Y with two pieces of Q Power Pro for the upper sections.

Q-Power Pro - Only has 600 lbs breaking strength (without including the sleeve material strength). Main advantage is from the tight weave on the exterior preventing abrasion. Because of my stretching problems and all of the power running thru that lower line, it does not solve the lower line power problem imo. Nice thin line around 1.25mm, good performance wise. I contacted a retailer, kiteboarding.com, about it. Never heard back. Sales dept must be too busy to sell. /shrug. ANother retailr, awindofchange, might offer better service than kiteboarding.com but I did not bother to contact them as I became a fan of the Liros solution by then.

DC-401 - the solution I ultimately chose. Based on newer sk-99 dyneema, it has a thin profile at 1.6mm and 580 kg of strength (1275 lbs). I can just order a spool and order whatever I want from a local sailmaker that cuts custom lines here on Maui and is familiar and capable with splicing lines/sewn knots/loops. The coating is made for kiting and the weaker version of the product, DC-301, is being used by Core for their Tectanium lines they are charging $750 USD on their Sensor 2S Pro bar. Having the same line material for the upper and lwoer section of Y matches Naish's original approach while offering a vastly superior material that can support me, eliminating issues with different eslasticities and offering the closest thing to an upgraded manufacturer product (sorely needed imo).

Purchase wise, retailer based out of Germany has been super responsive so far. Adv of a GER retailer (aside from reliability vs using a French or Spanish retailer, with the only USA importer being French) is that they were able to order the specific colors I wanted since Liros is based in GER and has some stock on hand in GER. I also have friends who live in GER who could go pick it up and handle the shipping if need be although the retailer has been proving competent at handling an international shipment so far (he knew not to whack me with the VAT component of the pricing). Waiting on my Carbon Grey DC-401 (flying) and Yellow DC-301 (steering) line spools.

Jerry Brown Hollow Spectra 1000# - weaker than either Amsteel or DC-401, has a 2.05mm diameter. Required ordering in bulk, price wise would have ended up more expensive than Liros with reduced performance.

Marlow Ropes (sold by gorilla rigging) - products not tailored for kiting. kite line race has a 1.3mm diameter and 270kg breaking strength (could not find this on their website though) while their Grand Prix D12-99 is 2.5mm and has a breaking strength of 677 kg. Its the same Dyneema sk-99 core but the products are not tailored for kiting and are either too thick or too thin.

Overall, this is what I came up with after a day's research. I am an American but travel alot and I am comfortable dealing with international suppliers. I have dealt with international suppliers/purchases from both a consumer and commercial perspective, importing via DHL/FedEx and sea based containers.

Relative to buying anything retail in the USA - comparing this line material vs buying Core replacement Tectanium lines, this is much cheaper.

Compared to buying local materials here in the USA, this is slightly more expensive (Amsteel/Q Power Pro combo would have been $30 cheaper).

Neither of these options offered the same strength/performance/color options that my approach offered, so it was a fairly easy decision actually. I suspect in the future more people will go down the same road, reading foilholio's posts from a few months ago he went down a similar path logic wise.

I will update this thread once I receive my materials and again once I complete my project of building my new lineset.

[edt]

Just a small word on drag and thickness of lines. Drag scales proportionally to the coefficient of drag times the velocity of the air times the area. And because we use kite lines this means that it scales as proportional to the diameter of the line. Notice however that the strength of the rope scales as proportional to the square of the diameter. So for instance, if you have one line that is 1.5mm and another line that is 3mm the 3mm isn't twice as strong it's 4 times stronger (the square of 2 in this specific instance). However! If you have a kiteboarding setup that uses a V (instead of a Y) that means you have two of these 1.5mm lines coming down to the swivel and you simply add up all the lines to figure the drag. If it's a 4 line kite that would be proportional to 1.5mm times 4. Now let's figure out how strong a line is that would be as strong as two 1.5mm lines. you do the squares and square roots and get a line that is 2.1mm. However, this single line that is 2.1mm will have drag that is only about 70% the drag of these two 1.5mm lines. So you see what I'm getting at here. All these other kites that don't have the Y work perfectly fine using two of these 1.5mm lines going down to a V and they can be either 4 or 5 line kites. You can have exactly the same amount of drag as those kite control bars that use a V if you use a 3mm line so I really don't think drag will be too much of an issue unless maybe you are racing. That's my reasoning behind thinking that a 3mm line for the Y will be fine. You will have exactly the same amount of drag that these other V kite control bars have but you'll have line that is about 40% stronger than the two 1.5mm kite lines.

[dracop]

I am not racing at all, it's an interesting point about a fat single line's drag vs two skinnier line's drag. altho is the extra drag of a 2.5mm line vs 1.6mm for that 11m section worth a little bit of extra breaking strength? I don't really know how much reduction in performance that would really be. I don't think I am going anywhere near that 580kg, do I really want to lose any performance for an extra 150 kg of breaking strength given I am way above spec? I am looking for higher breaking strength than what I have now because I am breaking and stretching what I have now (after heavy use) and testing shows a break strength of about 240 kg (elasticity and creep being a related function of break strength).

I do not have a perfect answer, I eyeballed it and decided to just buy a spool of DC-401 and run with that for my entire Y center. FYI, there is a DC-701 that is 2mm in diameter with 729 kg breaking strength. That is the same strength as Amsteel 7/64 but with smaller diameter. For my part, I felt the extra strength was unnecessary and not worth the extra hassle/cost of actually getting it.

If anyone chooses an Amsteel/Q-Power Pro combo, I would certainly be interested in hearing how it worked. I will report back how my Liros Wunderbar lines work out.

[edt]

2.5mm line vs 1.6mm

well if you do the full calculation, say you have 22 meter lines, 5 lines, lets include the kite for drag, the cross section of the leading edge of the kite is around 1 or 2 square meters on a 12 meter kite, depending on lots of factors (lets call it 1 square meter that's a worst case scenario) then you have 1.6mm diameter line with the 2.2mm Y part, so the total area of the lines is 0.0016 * 22 * 3 (rear lines + 5th line) plus 12 * 2 * 0.0016 for the Y part near the kite then 10 * 1 * 0.0022 for the thin Y segment you are buying for a total of 0.166 drag for the lines that a significant amount of drag, something like 15% of the total drag here is in the lines. Now I'm not doing the coefficient of drag obviously you need to calculate it for the the kite and for the long cylinder lets just leave that for now and continue see what we get. With the 3mm line you get a number of 0.174 for the surface area for the thicker 3mm line and a total of 1.174. Let's see what the difference is: 1.174 - 1.166 = 0.008. 0.008 / 1.166 = 0.7% more drag in the 3mm line. I suppose you might notice it but it would be difficult. Like I said I would just go with the 3mm. For differences this small it's hard to really tell by flying the kite. That's just doing your 2.2mm line vs my idea of a 3mm line. Should have run the numbers for 2.5mm oh well, anyway it's less than that.

You can do this other calculation of the 2.2 vs the 1.6 m line for the 2 front lines the same way if you feel like running your entire power lines 2.2mm both below and above hmmm lets see, 0.20 area so if you run this 2.2mm line both below the Y and above the Y on your lines you should see something like 3% more drag. You'll probably notice it if you run the 2.2mm the entire way.

What do you weigh, 100kg or a bit more? I bet you are pulling 3g in those loops, so you kind of want those center lines to be able to handle 3 * 100kg and then double that for a safety factor. If I were you, I would want my single center line (below the Y) to take 600kg and above the Y where it splits for each line to take 300kg. You can go above 600kg but above that it's more about getting some abrasion resistance because once you go above that the attachments on your kite rip off.

Or you could give up kiteloops, then you'll be fine with the original lines

[dracop]

2.5mm line vs 1.6mm

Or you could give up kiteloops, then you'll be fine with the original lines

BLASPHEMER!

I weigh 110kg right now, not including the weight of my board and soaked boots. currently living on Maui and I hit it hard anytime its 30-40mph winds (about twice a week it hits low 30s). How would I calculate the g-force in a powered kiteloop? No idea how to begin to tell that. Does the woo have an accelerometer that will tell you this?

I assumed a lower force than 3g, more like 2-2.5Gs), and then doubled that. Still within the 580kg rating. Well I do have my FrankenBar (Slingshot Center lines for upper Y lines and outside steering line), I could test Amsteel for the lower Y on that. I am putting my pretty lines on my Fusion Bar with matching colors.

[edt]

How would I calculate the g-force in a powered kiteloop? No idea how to begin to tell that. Does the woo have an accelerometer that will tell you this?

yeah the new woo and xensr have g force trackers, the problem is you hit these 7 to 10 g force landings and you dont care about that you want to track g force on liftoff so I'm not sure how you can sort out all the g forces. Looks easier to do on the xensr. But yeah 2, 2.5 3 g's that's in the right ball park. It sounds like a lot but really not a lot of force. 3g on the spreader for you is 330kg or 730 pounds, and I'm sure you've gone over that from time to time in a crashed kiteloop. It takes more than 700 pounds to straighten out a spreader hook, and I'm sure you've done that before. When you have a hard landing and smash a board in two that's probably over 10g's force, or 1,100kilograms, or one and a quarter tons. There's no point in making the lines too strong. somewhere around 600-800kg per center Y or 300-400kg per individual line is enough where other parts of the kite and harness start failing. But I do think it's worth it for you to go all the way up to 600-800kg per center and 300-400kg per line. Less swimming. By the way I know qpowerline is rated at 272kg (600 pounds) but it has always felt stronger to me for some reason and I haven't yet snapped a q-power line.

[dracop]

Haha! I got my new Liros bulk line in: some DC-301, DC-401, and DC-701

Check out the pics, different weave on the outside than production Naish lines.

[alford]

Very cool that you were able to "line this up"!
I'm still amazed how difficult it is to buy these lines here in the USA .
It's not like kiting is windsurfing here, kiting is a pretty common.