A Formula

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Blood Wolf
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A Formula

Post by Blood Wolf » Fri Oct 13, 2006 10:24 am

Hello there, the other day there was a question regarding KN. And it was said that 1 KN is 101 kg. Right, now is there someone that knows how to work out say I fall 5 meters on my protection how much weight is actually been put on my protection. You know there must be a lot of force on the fall and a lot of weight been pulled on the gear. You see I climb high before putting a bombproof piece of gear I would just like to know roughly if my gear can take those falls.
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Post by Justin » Fri Oct 13, 2006 10:59 am

Check out the Petzl.com Fall Simulator
http://en.petzl.com/petzl/SportConseils?Conseil=56 (Best viewed in IE / it also requires Java to be installed)

Also see the following thread - http://climb.co.za/phpbb2/viewtopic.php ... =simulator
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Post by Hector » Fri Oct 13, 2006 1:26 pm

U need to know how long u take to stop, how much rope is out, how much the rope stretches etc...

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Post by Rastaman » Mon Oct 16, 2006 8:25 am

What about the old trial and error method?

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Hey Rastaman

Post by Chalk » Mon Oct 16, 2006 9:36 am

tha's the splat- test you talking about - only two outcomes - to splat or not to splat...very scientific

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Post by Wynand » Mon Oct 16, 2006 9:47 am

Rastaman, The old trail and error method. And what happens if u end up badly in hospital, where you could have tried to prevent it by knowing +- what weight your pro can handle before u placed it. And what about your gear that has been used to trail and error should it have to take a serios fall will it still protect u then. Trail and error is a bit to scary for me thanx.

Regards Wynand.

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Post by Rastaman » Mon Oct 16, 2006 3:25 pm

Thats why it was a joke Mr Wynand.
But serious there is no way that you can predict the exact force that a placement will take. There are too many variables.
Factors like the strength of the rock itself, angle of the load placed on the placement, how good the belayer is ect ect.

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Post by Fred Fingers » Tue Oct 24, 2006 5:01 pm

Strange that those little numbers engraved on the gear intreages some people...
somehow i doubt whether petzel only caters for 45Kg people on size 6 nuts but if you are a bit heavier try the size 9.
dude it's made for all sizes of people doing all strange and crazy things.. like running it out more than the usual 1m weekend strubens route.
my vote is the splat test.. you'll never know!
let the guys with the thick glasses and pocket protecters worry about that you worry about the next hold.

go bouldering less maths.

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Post by RUPTO » Tue Mar 13, 2007 9:16 am

Basicly 1kg=10N (9,82N to be exact). When you free fall gravity sucks at about 10m/second squared. That means for every second you fall, you fall 10m/second faster 1m fall=10m/s(36km/h) 2m fall=20m/s(76km/h) etc.) To get the force on your gear you need to get the speed at wich you falling then x taht by your mass, this is called your momenum wich is equal to the differance in speed that you are doing after fall has been arrested(speed after free fall - speed after arrest (0m/s) x by force on your gear(this is what you are looking for).
If you are interested in this kind of thing please post reply and I'l try to simplify equations. This works on static lines only (the way all test figures are generated) and becomes extremely complicated once you introduce dynamic ropes.

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Post by scottnoy » Tue Mar 13, 2007 1:27 pm

When protection does fail, 99.9% of the time it comes out because of: (1)poor setting in the rock - moving around or bad placement (2) or the force of the fall breaks the surrounding rock...
So don't worry too much about the gear itself and more about your skills in placing it!

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Post by goo » Tue Mar 13, 2007 11:37 pm

Thanks for the petzl calculator link it was very informative.

It shows that if you are going to be doing long lead-outs above bad gear, do it with alot of rope out (i.e at the end of a pitch). So it is could be a good idea to adjust belay stances on a trad route with this in mind.

Obviously this strategy has the drawback that you will possibly be more tired, have less gear on your rack, will have to do this section with more rope drag and caring more rope. It also does not help if there is a ledge that you are going to hit…

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