Below is a picture (finally worked out how to get it to show inline) of the rigging.
I've only included one leg and set of rope for clarity, although the complete structure has the same thing duplicated both sides.
I think this should answer most of Dan's questions and also Dereks request for a layout.
Thanks for that, but I'm afraid it leaves me wondering, still.
For starters, I don't understand the seeming cylindrical object amind the legs,
which looks to be wheel-like, but then in that case is oriented perpendicularly
to the legs it lies upon/amid, and for taking movement on a surface (landing?)
also at right angle to the obvious curve of the leg ends!? In your linked site's
photos, there is no such object, and apparently the guylines of light & dark hue
can be seen in deployment.
It seems that these lines should be expected to endure some bit of "shock" loading,
though the amount of load put on them can't be all that much (for the frame, for that
matter); some amount of dampening elasticity should be helpful in this, I'd think
(and I'm not agreeing w/Derek's assertion about polyester--not in general, at
least (for I think he has evidence re his particular stuff)--, and could see nylon even).
As far as loops vs hitches vs bends, we prefer to make a batch of the rigging lines on a jig
then assemble them onto frames as we build them rather than have to try to tie the knots on the frame
and get everything the right length.
Apart from that it doesn't really matter how the knots are done as long as they meet the criteria of being small,
neat, reasonably secure (we can always add some heatshrink or some such if needed) and reasonably strong.
Hmmm, it would seem to me to be problematic to have very-static line so right-sized
as to be able to be so fit (or that all necessary tolerances lead to such a plan), versus
making attachment in a way that you individually set each line-pair correctly. Now, maybe
the lines are the final determinant of the full-open position of the landing gear, and in that
can be within some comfortably variable range of lengths such that pre-tying is practical.
One could also see using the thing & high-strength but static HMPE line with small thimbles
& eye splices (or just a "soft" eye), and tied to poles for the final few inches by some elastic
cord, achieving attachment with the more knottably happy material and gaining some bit
of shock absorption via it!? Now, maybe this would be for the ENDS, only, and the center
(between cord-legs, i.e.) loopknot would be just that; for that, something link a well-set
Fig.9 or Fig.10 LK should work. (I can even imagine a sort of Blood Knot in the Bight.)
2. Is the Spectra core braided or strands? The core is non-braided strands, the sheath polypropylene.
So, very low stretch, high strength (unknotted!).
Hollow braid vectran has been suggested, I'm looking into that but initially it looks like an expensive option.
Can't see the rationale for Vectran (tm)--less UV resistant, and if anything I think less
shock resistant.
the Southern Ropes Dyneema Lite we are using now (175kg bs).
Although that seemed to work, I'd like to ensure we have the best safety margin possible with the materials we are using.
I doubt anyone here can attest to this--you'll have to just test whatever candidates there are.
It certainly is NOT the case that general, traditional "data" about knot strengths can be relied upon!
--dl*
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