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Re: [joeforte] bAD fIXED pRO:
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mattm
Dec 16, 2011, 10:14 PM
Views: 2775
Registered: May 20, 2003
Posts: 640
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joeforte wrote: The revolver reduces the friction of the top piece, allowing the entire length of the rope to take the impact. A falling climber has the same kinetic energy regardless of what 'biner is catching him. The revolver just allows more of that force to be dissipated by the belayers side of the rope.
Read that Supertopo thread. It's not as straight forward as you'd think. With so many variables, we're probably just blowing hot air without empirical evidence through drop tests and load cells. (Calling Jim Titt or Sterling Jim...)
The question is, does including more rope in the energy absorption system outweigh the increase in the pulley effect?
One of the benefits of the Revolver would be on LOWER pieces. By reducing friction from rope drag on lower pieces the revolver helps to include more rope in the system. I'm all for that. (See Beal's site on impact forces, GriGri's etc. They have a good diagram of how multiple rope bends increase loads on the top anchor.)
http://bealplanet.com/...s/facteurdechute.php
Without testing multiple scenarios, you can't say the Revolver universally reduces the load on the top piece. It likely does IN SOME CASES but is probably detrimental in others.
There are also down sides to having that force transferred over to the belayer side of the rope. It's why I AVOID placing a revolver on the first few placements.
I suspect using a screamer and low impact force ropes will do more to keep peak forces lower than throwing a Revolver on there.
People just need to be aware that there's more at play here than basic physics and there are downsides to a revolver being in place in some circumstances. Until there's testing, we're just participating in conjecture.
I use Revolvers, just not on my "dicey piece" screamers.
(This post was edited by mattm on Dec 16, 2011, 10:23 PM)
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Post edited by mattm
() on Dec 16, 2011, 10:23 PM
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