foilholio wrote:
The stitch or splice needs to take the load evenly onto the larkshead otherwise it would be weaker or slip. Try cutting half or all the stitching off your front lines and get back to me
Ha ha good timing, unrelated to this post I was out yesterday and one of my sketchy stitch jobs gave up on life after a few years of use rode it for 3 hours like that. (half stitches gone) complete with underwater kite loop and a jammed safety, mild deathloop scenerio (not caused by the line breaking or failed stitching) and some WELL powered tricks. Wouldn't advise it, again performance in gusts and jerks would be diminished greatly but it held up to all that abuse just fine. pics are a pain in the butt, but I can attach one if you need it. I'm using basic polyester sail thread for those joints. Didn't take it up to rated load but worked the crap out of it that's for sure.
foilholio wrote:
Having tested stitching on lines it can contribute a lot to strength perhaps close to 100% if done over a long enough piece.
Agreed, but i don't believe on flying lines they are long enough....because they don't need to be. (I am referring to the typical unburied sleeved and stitched kite line) The larks head and stopper knot of most connections make sufficient friction that the stitching is rarely loaded and almost never in full tension unless the connection becomes loose.
For their intended purpose of comparing different joining splicing and bury methods your tests were fantastic and thank you for doing them. Please appreciate that they were not done on typical 600lb kite line. I would be extremely surprised if the thin POLYESTER stitching they use for 2-3 inches on kitelines is somehow able to hold near 600lbs of force. There just doesn't appear to be sufficient area of polyester to do that given it's strength. the friction from the larks head holds a great deal.
foilholio wrote:
Also with kookproof connectors, one end isn't larksheaded.
Incorrect you need to consider the ASSEMBLED condition.
Both ends are larks headed.
one the kite puts a larks head on the kite line squeezing the crap out of it preventing slip through friction .
on the other end the kiteline puts a larks head on the kite end squeezing the crap out of itself preventing slip through friction
In the assembled condtion the effect is the same. it takes considerable load off the stitching.
In addition there is a stopper knot that acts to prevent slippage/unload the stitching.
foilholio wrote:
Also flying lines are barely loaded in most use.
???!!!!
the flying lines combined carry 100% of the load the kiteboarder sees. they are THE MOST highly loaded part on the kite...and the smallest area
I think i get where you're coming from though
There was a video circulating around a while back with some poseur mowing the lawn and doing some dingle dangle jumps with some force gauges on the line and they didn't have much load...I advise against making conclusions or extrapolations from that......guys here have bent and broken bars.
Johnny Rotten wrote:Any joint I plan to stitch I test if under tension in it's assembled arrangement (without stitching) to determine if the line will come apart on it's own
foilholio wrote:
If this is for a splice then it is fine, I do it to "set" the splice before stitching. If however this is for a line end that is "only" stitched, well this is one of the most pointless things I have ever read.
Then you are missing my point, You can fly your kite loading polyester sewing thread if you use enough of it and it's evenly distributed .....but understand you'll need ALOT and is difficult to guarantee/likely to fail... You can stress about brummel, bury depth and taper etc .... Or you can use a type of attachment method to ensure you're flying loading the 600lb dyneema....and the polyester or brummel/bury is back up only...
Johnny Rotten wrote:I have yet to come across a factory line that relies on stitching strength
foilholio wrote:
Just about every flying line does and most kite bridles. I think you have observed things incorrectly. Testing these lines it is only the stitching that could be creating the strength there is nothing else. I am talking about testing them without larksheads too where they can still get 85-90%+ strength.
I'll take a look at some bridles (mot of my kites are C kites) but I suspect you are also wrong here...stitching is likely back up only in the assembled/usage condition and there is a Chinese finger trap bury going on
foilholio wrote:
Again the stitching provides strength, on line ends that are solely stitched it provides all of the strength in combination of course with the line/rope fibers. You can observe this and you can test this and because of that I won't argue much on it further.
I haven't found an easy/practical way to get 600lbs through a test rig and load a line correctly without owning a 600lb force gauge. I know you tested lower rated line intentionally for this reason but send me a pic of what you did maybe I'll get some inspiration on how to make it go for heavier stuff and do it myself ....Or maybe you f'd everything up altogether, the last dude to test lines, got the units wrong....hey stuff happens.