A small group of local fliers came to the west wind spot. gusty from the west 15-30mph on a rising tide.smooth spot next to the chop section. crowded for the regulars for about an hour but fun

a guy flying 12m tube (about 170). he and i fly together alot. 5year seasoned rider, olympic candidate windsurfer. i recommended Q-powerline , maybe month or 2 ago ,. any way roughly 2 hours into the ride his line fails.

any thoughts on this premature failure. failed at the loop knot

Failures at the knot are the most common with any line. Q-power is one of the best lines on the market but line failures can happen to any line.

When the knot is tied in the line, it puts a lot of stress on that exact point of the line. The stronger the wind or gusts, the more stress gets placed on the knot. What will happen is that the knot will start to break down the individual strands of spectra on a line which will slowly weaken it over time to the point it will break. It is always good to give your lines a good once over before the start of any session, especially around the knot areas to make sure there are no abnormal wear or excessive stretching which will lead to a line failure.

A couple things that you can do to help limit the amount of stress - instead of a normal square knot, use a figure 8 knot. The figure 8 will reduce the stress on the line by nearly 60% compared to a square knot.

Here's the beauty of Q-powerline, all you need to do is pull all four lines tight, with a marker draw a line across all four lines about 8" up from the end of the shortest line. Fold em all over and re-tie them, cut off the excess and your back in the air. Can't really do that with any other line on the market.

Hope that helps.

This is odd to here ? I thought that one of the main selling points of Q-line was that it didn't require a sleeve ?

I have some old stuff with the casing all cracked and still no failure ?

I don't think it's likely but wonder if the inner cord was a part of the knot ? If it was just the outer casing I can see trouble !

i told him layout, cut to shortest & retie. should be fine

they were new maybe 20 -30 hours.

it was gusty, he was saving the runaway kite i was dragging the owner.

Ouch, anything mechanical is prone to failure. I've only had a single Q-power line break and that was winter 1999.

Make sure all knots are figure 8 knots. Make sure the lines in the knot are all straight and not twisted about each other more than they have to be.

I've got a feeling it was a square type knot. Figure 8 knots are kinda hard to tie correctly and get the lines equal length and the knots pretty.

Or he's just got a bum line.

Scott

bought custom & knotted, AWOC, i don't think prep was a problem. things break , as a matter of fact i got the set of lines he had order from a local dealer as they were the wrong length and.... that set of lines broke on me in about a month. he has had a rough go of it past few months broken board , numerous bladders, bridal lines, now 2nd break on fly lines. champion flier, takes extreme care of gear as well.

i follow the neat parallel finish to all my loops as AWOC describes with the line lesson.

which appear to be overhand

parallel Sewing - zigzag stitch is the ideal way to terminate shielded line like Qpower....

then its really sexy if you put heat-shrink over the stitched section.

i am all about sex appeal ...just don't want to be dropped by a knot cutting the line.

the figure of 8 i use http://www.animatedknots.com/fig8boating/index.php?LogoImage...

Q-Power does not need to be sleeved although you can sleeve it if you would like and it will help with the overall strength of the line at the knot.

Any line will lose some of its strength when a knot is tied in it. The knot crimps down on the line at one spot putting extreme amounts of force and stress on one single point. This will weaken any line regardless of type. As mentioned in our tutorial, make sure that if you use a square knot, you make sure that the two lines in the knot are perfectly parallel through the entire knot and not twisted over each other. This will help reduce the amount of stress that the knot adds to the line. We use square knots when we make our custom linesets and in most situations the square knot is more than adequate. If you do find that you are having excessive line failures at the knot or if you are flying in normally stronger wind conditions then you may want to use the figure 8 knot which is said to be less stressful of the line.

I usually re-tie my lines any time I find any type of wear at any knots and this usually eliminates any type of line failure from the knots. You do lose about 6" - 10" each time you re-tie all your lines but I have never had any ill effects from it.

Hope that helps.

It might just be a bad batch that ya'll have gotten into.

Scott

thanks kent

i have sleeved and salvaged alot of used gear and never had a problem with the reworked loops...the "new"stuff .....is new and thought it warranted feedback discussion.

btw the old guitar string fid is my favorite, i thought i was original til you mention it.

been wondering what to do with the clipped loops? hate to discard.

I used figure 8s on my lines but havent had a chance to use them yet.................thanks for the intel. Have to say these lines are well made..........................

I like doing what Powerzone said with the stitched sleeved loops. Knots or stitched loops will always be the weakest point, wether your kiting or fishing or anything that has to do with lines.

Only lines I've broken were old... new lines always seem to get cut when your buggy'n along at a high speed and don't see the cheapo deluxe kids single line kite with three miles of cheap line out... until you hear the sound of your spectra parting and your kite floating to the ground.

Figure eight knots are said to be up to 80% efficient- meaning they preserve 80% of the line strength. But one study suggests that the efficiency drops to 53% in Spectra.

Sources and citations here...
http://www.coastalwindsports.com/FigureOfEightKnotTutorial.h...

Tied correctly Q-Power line is the best line out there. I use 300 pound Q-power exclusively on my kites. Never had an issue. I've got a couple lines that are almost 10 years old and going strong. By mid next year they will be 10 years old.

Scott

Here is a link showing how to splice loops. Looks way better. Way stronger and is pretty easy to do


http://www.nwkite.com/forums/t-11649.html&sid=0f28cd6e0a...

There are better ways to splice loops in single braid. See this step-by-step for a modified Brummel splice that locks the tail even if the line is slack (without stitching): http://www.newenglandropes.com/SPL_12Strand_EyeSpliceBrummel...

I believe the Q-powerline referred to in the thread is cored, so splicing doesn't work. I stitch my cored lines, usually with dacron sleeves over it. Use caution with heatshrink - I recollect reading an article showing up to a 50% tensile strength decrease in many high modulus polyethylene lines when heated to the temp heat shrinks are designed for.

krumly

Anybody notice a lot of line drag on the q-powerline?? its so fat that i would think it would drag a bunch... is this true?

I would be using it mainly for land kiting, if that makes a difference

300 pound Q-Powerline mains and 80-150 pound Laser Pro Gold line for the brakes. This setup has little drag.

Scott

i don't use Q but it seems new market standard, i dacron sleeve it all

since he has been on this line his rig sings all the time.

line sing (whistle,whatever it is)is a result of drag vibration i assume

or is it from load tension threshold resonance ....any way the Q sings more than the rest so i have noticed

not sure the weight he got but i would think 600

def see the advantage smaller cross section,

my skills are refined but not enough yet to goof off too much on 300 with out trouble @200lbs that seems too close for me. ultra smooth flow on light lines def seems like it would be faster.

I threw a set of #300lb on both front and rear lines on my old 3m Brooza. The drag made a big difference and the kite performed real poorly. I expect a lighter set on the back would have changed things a lot but I have started to just use it in my larger kites fly lines.

I agree, Mine sing sooner and louder than anything else I use :singing:

Quote:

Originally posted by speleopower 300 pound Q-Powerline mains and 80-150 pound Laser Pro Gold line for the brakes. This setup has little drag. Scott

300 is way to much on the rear. Put some ultra light stuff on the back and you'll notice a huge difference.

The 300 pound mains have worked for me up to kitesurfing in 50ish+ mph wind one time on a 2 meter foil. Never a hiccup. But to each their own. :wink2:

I was flying my Blade III 10.5 meter kite today in 2.5mph wind. My friend has a wind meter and that is what it was showing on the ground. The kite was sitting up high humming away. I also put 2 30 foot tails on the tips of the kite for good measure. Flew like a champ. 300 pound mains and 80 pound brakes.

Scott

my original set of Q's are 9 years old. One of the lines had a break in the outer casing since forever and the line never parted. i bought a new roll and replaced that line a couple weeks ago (just in case). I've noticed th8e new line is a different texture being less stiff and a little more stretchy.

i've always used figure 8's with never a line failure, but I have cut the loops and retied as a preventative measure. But on the kite end of the lines, i've gone to using an addition "dynema" loop that larksheads to the q line and larksheads to the kite. this helps in 2 ways; the dynema knots are way easier to untie than the qline (larksheaded) knots and as lines stretch, i can make new loops to adjust for the uneven-ness.

I love to hear the q lines 'sing'. if they're not singing, then there's not enough wind (for me).

Singing lines....everyone has heard them but it is obvious that most people don't really understand the singing and what that is.

The posts above are somewhat correct that the singing of the lines is the vibration of those lines which creates line drag....but...that's where the posts start to drift from the actual facts.

ALL LINES VIBRATE, this is true weather you can hear them or not, they're still vibrating when being flown.

The vibrations in the lines are the same as sound waves, lower vibrations are not nearly as audible as higher vibrations but, lower pitched vibrations are much longer and wider than higher pitched vibrations.

Line drag is created from the line passing through the air, it has been proven that a single thread can have more line drag than a 6" diameter pipe, the reason is because the single thread will vibrate in an uncontrollable matter, creating great disturbances in the air flow and thus, greater drag than the ultra smooth and stable 6" pipe does. The air flows around the pipe much easier than it does through the turbulence and distortions of the single thread.

So, getting back to line vibrations...
Maximum line drag will occur from the widest vibrating point of the line, not from the diameter of the line. So, a very thin diameter line that is vibrating wildly at a very low (subsonic) pitch will create much more line drag than a thicker line that is vibrating in a more controlled manner and higher (audible) pitch. Remember that every line vibrates, the lower frequency vibrations will create a wider sine wave than higher frequency vibrations so a line that is vibrating at a higher pitch creates less overall parasitic line drag than a line vibrating at a lower pitch - this is usually true regardless of physical line diameter because the vibrating frequency of the line is usually much wider (usually 10 to 20 times wider) than the actual diameter of the line.

Q-Power designs their lines with a special linear weave outer wrap that protects the ultra strong spectra inner cord. This linear wrap yields a stiffer line that is less prone to tangles. The wrap also creates minuscule wind channels that allows the air to flow evenly around the line, the construction of the line also causes the line to vibrate at a much higher pitch which reduces the overall parasitic drag created by the lines as they are flown (this is the high pitched whine you hear when using Q-Power line).

Q-Power is the only company on the market that has scientifically "wind tunnel" tested their lines against all other major line manufactures on the market and has proven that their lines have up to 45% less parasitic line drag than other spectra and non-spectra lines. Q-Power is also one of the leading manufacturers of line for many military applications as well as the number one recommended line for kite surfing.

Brian from Powerline Sports should chime in here as he would have much more information on their lines than I have. I am not associated with Q-Power at all but we do stock and sell their lines. In my opinion, Q-Powerline is the best line you can buy for any type of power kiting sport.

So, now you know why your lines are singing to you.

Probably the most useless bit of information on here, but it will give you all some conversation the next time your standing around BS'ing with your buddies when there isn't any wind blowing.

I always knew my kites flew better than everyone elses. Now I know why! :wee:

Scott

Another thing that has worked for me in the past to stop lines for breaking at the sleave. I have found that when the sleaves are hot cut to prevent them from coming apart that this makes a sharp area around the line and lines tend to where and break. What I have been doing for years and years and has stopped my lines from breaking at the sleave is to run the line out the side of the sleave before the hot cut and of course do the same at the front of the sleave. This has stopped me from breaking any lines at the sleave.

Big John

Quote:

Originally posted by JoJo1 What I have been doing for years and years and has stopped my lines from breaking at the sleave is to run the line out the side of the sleave before the hot cut and of course do the same at the front of the sleave. This has stopped me from breaking any lines at the sleave.

Save a step! I haven't hot cut sleaving for years. Just cut the sleave to length and tie the knot as close to the fuzzy ends as possible. I had the same problem you were having John. This fixed it for me and saves time too.

Also a good (long) post here on lines... http://www.nwkite.com/forums/t-11649.html&sid=0f28cd6e0a...

That would work as well Bison, but we got a **** load of the quick sleave packs years ago under sponsor stuff and I am still using that until I run out. It is all hot cut, but it is quick to sleave the lines. That's why I tried oother ways with it to finally find just go in the side in front of the hot cut and come out before the hot and there is no problem. Of course once I finally get through with all of the quick sleave kits I have and start making my own again I will not hot cut it. Factory made lines sleaves are hot cut and I am sure that is the reason for them breaking at the knot.

Big John

Quote:

Originally posted by bison Quote: Originally posted by JoJo1 What I have been doing for years and years and has stopped my lines from breaking at the sleave is to run the line out the side of the sleave before the hot cut and of course do the same at the front of the sleave. This has stopped me from breaking any lines at the sleave. Save a step! I haven't hot cut sleaving for years. Just cut the sleave to length and tie the knot as close to the fuzzy ends as possible. I had the same problem you were having John. This fixed it for me and saves time too.