On a recent thread in the For Sale section I posed this question:

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Can you fold and stitch the loops on the Pro version? How about splicing and stitching the ends? I'm hoping to do a knotless end so it can connect to a 4.5 line and pass through the stopper.

I bit the bullet and bought some 600 lb Q-Powerline (not Pro) and did some experiments with stitching Q-Powerline. It worked well.

I modified a presser foot on my sewing machine making a 3mm groove in the underside of the foot to keep the lines squeezed together while I zig-zagged a folded end together. I folded about 200mm of tail back and stitched about 150 mm of it using a heavy polyester thread.

I had to test my handiwork so I set up a block and tackle on the kids fort to do some destructive testing. For the first test made a short segment with one stitched end and one tied end. I loaded it up with myself and Katie harnessed to the end of the block and tackle. It broke at the knot at about 400 lbs load. Did I dress the knot well? Somewhat, but I'll confess it was not my best work.

In test number two I stitched both ends and loaded it up again. This time it broke at about 550 lbs load. The break was where the stitched line meet the straight part.

That was good enough for me so I made myself a line set with stitched ends. I then proceeded with the my plan to make a 4.5 line setup like Krug described in http://www.powerkiteforum.com/viewthread.php?tid=20184

I'm really glad I went with the stitched line end. The knot in the Q-Powerline was huge--it's 6 mm x 4.5 mm. The stitched line is only 3.5 mm x 2 mm. When I larks-headed the flying line to the leash-leader the whole assembly 6mm at its widest. I would have had to uses a fatter leader for my leash just to make it engage with the stopper ball and I would still risk a snag at the knot. The fatter leader woudl have to go through the bar as well and that probably would nor work on this bar. So stitching the ends is a good thing.

As for the splicing the ends, I think it's impossible. I didn't try, but the sheath has an incredibly tight weave. I don't see how it could spliced.

FYI, I made the stopper ball custom from a short cylinder of delrin. The hole for the stitched line was 11/64. The leader side was 5/16 of an inch. I drilled the leader side to about 2/3 the depth of the slug of delrin.

I haven't flown it yet but the static test worked well. Disengagement was nearly effortless.

Philip

Do you have pics of your handy work you could share????

Thus far I have pics of the stitched ends and the presser foot that made it possible. See https://plus.google.com/photos/116935021710436287021/albums/...

I'll open up the bar tomorrow to get shots of the stopper ball.

To me the stopper ball is the bit of custom magic that makes this work. Stitched lines are pretty much the norm, but the ball needs to be custom to match the diameter of the end of you flying line and that of your leash.

If you want to stitch your own line ends the presser foot is another required piece of magic. To make the foot I did these steps:

1) clamp the foot in a vise, bottom side up.
2) apply tape to the botom of the foot so you can mark it.
3) mark the center line of the foot on the tape.
4) mark lines left and right of the center line 1.5mm away from it.
5) cut the left and right edges of the groove with a file to define it's limits. Drag the file fore and aft the chine of the file aligned with an edge line.
6) deepen the groove to at least 0.5mm. Make the feed-in end of the groove the deepest to keep the line from jumping out of the channel as it feeds in.
7) remove the needle from your machine and test the feed. verify the the line will squeeze together with no gap as it passes through the needle zone.
8) Put that needle back in and start sewing!

Philip

Thanks pbc..... it will be interesting to see your stopper ball set up......

I just did a set of standard q-powerlines and tied the ends...... I didn't measure the knots but so far no issues with flight. adding pigtails or extensions.

Even though q line doesn't need to be sleeved I wonder if that would add to durability of the sewn ends????

It might help, but I was after minimum flying line diameter with minimal snags. Nekkid line was the order of the day.

Philip

well done ! i sleeve Q if contacts metal....just me and wear points as fare warning casing fail first.

Lot's more pics added to https://plus.google.com/photos/116935021710436287021/albums/... I show the whole bar, the stopper, the self-landing handles I made, the freaky-tiny chicken loop, and the way cool cleat.

The self-landing handles are over-kill if the 4.5 line works right. The chicken loop is my least favorite part. It works, but hitching in and resetting it are a bit fiddly. Anyone have a good way to make a tiny chicken loop from scratch?

Philip

Philip
like the bar - only dont understand the micro chickenloop- why so small and what are you hooking it into? looks to small to even hook to a regular spreader bar. I need to order one of those camcleats though, i really like tht idea over the strap
Scott

Tiny chicken loop moves the bar and the trim closer to the rider. This makes it more suitable for smaller riders.

The loop--as small as it is--is compatible with a carabiner hooked into a climbing harness. The carabiner itself is a bit if a problem as it adds length between the rider and the bar. I am hoping to find a shorter option.

Philip

philip,
Andrew is still using a climbing harness as well and have found that by hooking the biner into both loops (leg loop and waist) reduces the reach by about 2 inches, FWIW. small loop makes sense now
Scott

That is a nice setup Philip......

I have a thing called a "D ring" from my rappelling days. It would connect your leg and waist loops and not add more than a couple inches. It doesn't have a gate, only a screw closure.

Talking with Brian (Powerline Sports) a while back and we were discussing line breaks and he was telling me that when you see a break a few inches from a knot the break initiates internally at the knot with the linear strands and then often the break will travel a short distance to the shear point. He also told me the best thread to use for sewing is spectra (which he produces) and when I questioned running it through a machine and friction and melting he said he has one manufacturer that has built nitrogen cooled sewing machines to use it (tens of thousands of dollars for those)

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Originally posted by markite Talking with Brian (Powerline Sports) a while back and we were discussing line breaks and he was telling me that when you see a break a few inches from a knot the break initiates internally at the knot with the linear strands and then often the break will travel a short distance to the shear point. He also told me the best thread to use for sewing is spectra (which he produces) and when I questioned running it through a machine and friction and melting he said he has one manufacturer that has built nitrogen cooled sewing machines to use it (tens of thousands of dollars for those)

Wow, get one of those and you'd def have the only one on the block!

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Originally posted by markite ...He also told me the best thread to use for sewing is spectra (which he produces) and when I questioned running it through a machine and friction and melting he said he has one manufacturer that has built nitrogen cooled sewing machines to use it (tens of thousands of dollars for those)

"Best" depends on what you're optimizing for. If your business is selling liquid-nitrogen-cooled sewing machines I think Spectra thread would be fantastic stuff.

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Originally posted by flyguy0101 philip, Andrew is still using a climbing harness as well and have found that by hooking the biner into both loops (leg loop and waist) reduces the reach by about 2 inches, FWIW. small loop makes sense now Scott

That could be a much cheaper option that the Ronstan quick-release awesomeness I was considering: http://www.kitesurfari.com/proddetail.asp?prod=Ronstan_Shack... I like it because it's shorter and I like the QR as an extra layer of safety, but the price is a bit steep compared to my $5 carabiner.

We'll try out the leg-loop trick.

Philip