stitchless canopy line sets (possible?)

[JerryBaumchen 1,046]

Hi Beatnik,

Send me your snail mail address and I will send you a No-sew fingerlock sample. I will also send you some line to try making one for yourself.

I do not call it a 'knot.' I call it a lock.

JerryBaumchen

PS) Once you make one for yourself, then you can spend the $$$ for the testing to determine the reduction in strength. Just remember to compare any reduction in strength to the reduction in strength of a fingertrapped & bartacked line.

[Beatnik 2]

No need, I have done lots of them myself since the method was introduced and have lots of line.

To me it is a method of fastening the finger trap from coming undone with the line. To me that falls in the definition of a knot. But what we define it as has really nothing to do with the argument.

As for testing it is something that can be done at a university and I happen to know someone who works in an engineering department of one to get it done so there really isn't any cost. But I have other things for destructive tests than this and am well aware of how to do research. Mathematically I can prove with using statics that there will be a reduction in strength compared to a standard fingertrap because of how forces are transferred down the line with bringing it through itself.

If I am buying a specific line for its strength, I see no point in reducing it at a specific point. This is why you taper the line in a fingertrap opposed to a straight cut. With a straight cut the angle of the fibres in the line are redirected sharply on the outer sheath of the fingertrap and causes a load in a direction that will cause a failure.

I am not saying that this method can't be used successfully in applications for instance your softlink method where the force on it is drastically reduced with the wraps done of the link.

I am not going to get into a forces lecture here more than I already have. I just wanted to bring another aspect to this conversation that hasn't been brought and maybe a reason why this method might not be used.

[JerryBaumchen 1,046]

Hi Beatnik,

No problems for me. And a well written reply IMO.

And it is always good to have a friend with access to a testing machine. I also have access to a testing machine at a local forge company that I used to work with. Sure does let me play around with a fair amount of 'stuff.'

If you get the opportunity, look in an original Parachute Manual ( the 3-ring binder version ) at Section 8.2.1.C.2.b.

JerryBaumchen

[Ronaldo 0]

Hi Jerry! Hope all is well.
Yes I have already relined at least 5 canopies using this method. One of them with cascaded Vectran lines but the other ones with continuous HMA. You only need a sewing machine to attach the lines to the stabilizers.
I have also replaced a few brake lines and kill lines using this method. I have 2 canopies relined this way, one has over 400 jumps with no sign of trim change.
Blue skies

Ronaldo

Engineering Law #5: The most vital dimension on any plan drawing stands the most chance of being omitted