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sween345
climber
back east
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Milktoast,
Forget the pistol and check your thread on hiking boots.
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zBrown
Ice climber
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https://mickeythompson.wordpress.com/2014/02/10/winch-steel-cable-vs-dynamica-rope/
Dynamica Rope is made from Dyneema fibres which is one of the strongest fibres in the world. The rope has excellent properties with regard to strength, weight, UV-stability (daylight), safety, abrasion, tension fatigue and bending fatigue.
When comparing Dyneema to steel it is ten times stronger per unit of weight. This means that a Dyneema rope has a slightly higher strength than a steel wire of the same dimension but less than one tenth of the weight. While steel wire can take 6500 loads at 50% of the maximum breaking load, a Dynamica Rope can take 10 million cycles at the same load level making it long lasting and safe.
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Winemaker
Sport climber
Yakima, WA
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Walther PPK of course. Interesting topic (rope that is) and some thought in the paper. Changing the dynamic of the rope under load.
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Steve Grossman
Trad climber
Seattle, WA
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One issue with designing an "ideal" climbing rope is continued use. If all of the shock absorption is used up in a single fall then you can switch ends once and take a second one which won't leave much in reserve for the rest of your fifty pitch route or expedition.
Ropes are pretty damn good at this point in time and you can get what you want if you shop around and compare performance qualities. Using more shock absorbing draws like Yates Screamers would be a better way to solve this problem in a sustainable fashion IMO.
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RussianBot
climber
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Silly scientists are always speculating about stuff they don’t understand. That’s news? Just ask me and my awesome understanding of the difference between theory and reality and I’ll set them straight. Really. ?
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Yury
Mountain climber
T.O.
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I am confused.
Do they want to use recycled memory foam matresses to make ropes?
Probably Dyneema static rope with a shock absorber at a climber's rope end (that can be tuned during a climb) can be an ideal solution from weight + arresting force criteria.
On the other hand I am not that sure about longevity of such rope.
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Ed Hartouni
Trad climber
Livermore, CA
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from the conclusions section, first sentence:
We do not expect this paper to have an immediate effect on the climbing community, but by providing a prescription for a mathematically ideal rope, the work may help guide the development of new ropes.
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Jaybro
Social climber
Wolf City, Wyoming
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Mar 11, 2018 - 04:44am PT
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Gotta start somewhere ( not to say that it (the rope grail quest)wasn't started a long time ago) I applaud their efforts and look forward to see what comes from this.
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rgold
Trad climber
Poughkeepsie, NY
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Mar 11, 2018 - 06:28pm PT
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To add a bit to my previous comments ( http://www.supertopo.com/climbing/thread.php?topic_id=2840129&msg=2840759#msg2840759 ), the mathematics part of the paper is to prove that, for a given length of rope and given amount of elongation, the minimum force on the falling climber will be obtained if the rope is able to resist with constant force. This would make such a rope more analogous to a reusable screamer and not at all like the "spring-like" ropes we have now, and contradicts the suggestion made earlier that to get a softer catch you need more stretch.
Without knowing anything about hydraulic arrestors on aircraft carriers, comparing the ideal rope model to those seems likely to be wrong, as I assume (perhaps incorrectly) that "hydraulic" means the resisting force is a result of viscous damping and so is not constant but rather proportional to velocity.
What I haven't gotten from my so far cursory perusal is whether the system is "scalable." Different rope lengths and different elongations presumably require different constant resisting forces from the rope. I'm not sure how the variability of those parameters is encoded into the material behavior. It would mean that the constant resisting force would have to vary depending on the initial velocity of the stretching when the falling climber just starts to load the rope, and I'm not sure whether something like that happens with the materials in question.
Another possible error is that the authors say at least twice that modern climbing ropes stretch 15%, but the amount of elongation for a UIAA-level impact is actually more like 30%.
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Lorenzo
Trad climber
Portland Oregon
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Mar 11, 2018 - 06:54pm PT
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All well and good but what pistol should I buy?
DMT My answer depends on which way you want to aim it.
But since you need somebody to answer for you, I’d say a starter pistol would be good.
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