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Chain Reactor...unusual specs?
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Roasta


Mar 6, 2008, 12:52 PM
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Chain Reactor...unusual specs?
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I posted this in the 'Gear heads' forum with no success - hopefully some one here can help.

Firstly I don't want to spark the 'What PAS is best debate' just after some interpreting help - so to speak.

Looking at the Sterling PDF link attached can someone please shed some light on their ratings for the reactor..(Bottom right corner)

I calculate that 3934lbs MBS should be around 17.4KN yet the KN rating is down as 12.4KN??

Also, compare to the standard 11/16th webbing 'Loop' rating of 22.6KN. I assume this is referring to a sling as such, which to me should be a similar concept of the individual loops in the reactor. Maybe they are differing 'nylon' materials - not sure.

With ref to the other link attached showing 'unofficial' BD tests on joining slings, I understand that the end to end strength shouldn't be the same as each single loops strength due to loss from loading sling on sling.

So I would appreciate if someone could have a shot at clarifying what I am reading here.

I am slightly confused.....

http://www.sterlingrope.com/...t_technicalspecs.pdf

http://www.bdel.com/...p_archive.php#052107


sterlingjim


Mar 6, 2008, 1:49 PM
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Re: [Roasta] Chain Reactor...unusual specs? [In reply to]
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Fixed your links.

http://sterlingrope.com/...t_technicalspecs.pdf
http://www.bdel.com/...p_archive.php#052107


The 12.4kN is a misprint. It should read 17.5kN.

As for that value itself considering the BD test; the Reactor is tested by being pulled end to end. In other words the test is not just for individual loops so there is a loss of strength due to the webbing crunching (or bunching) and not loading all the strands of the web evenly.
Hope this helps.

Jim


Roasta


Mar 6, 2008, 2:30 PM
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Re: [sterlingjim] Chain Reactor...unusual specs? [In reply to]
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Thanks Jim.

Just the man I hoped would reply. I didn't want to contact and annoy the company direct initially in case I was having brain fart and was reading/converting something incorrectly.

So would it be reasonably safe to assume that 'each pocket/loop' would be rated at or near 22KN and therefore the end to end figure indicates an approximate 4.5 KN loss in strength due to the reason already spoken of?

Not sure what happened to my links - thanks for fixing.


(This post was edited by Roasta on Mar 6, 2008, 2:33 PM)


sterlingjim


Mar 6, 2008, 3:52 PM
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Re: [Roasta] Chain Reactor...unusual specs? [In reply to]
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Roasta wrote:
So would it be reasonably safe to assume that 'each pocket/loop' would be rated at or near 22KN and therefore the end to end figure indicates an approximate 4.5 KN loss in strength due to the reason already spoken of?
That would be correct.

Roasta wrote:
Not sure what happened to my links - thanks for fixing.
If you just type in the links without using the url code the posting window chops it down, I think.

Roasta wrote:
I didn't want to contact and annoy the company direct initially in case I was having brain fart and was reading/converting something incorrectly.
I was pretty worried I'd be swamped with PM's and emails once I started posting here on RC but that fear turned out to be for nothing. Folks are welcome to contact me with questions directly if they wish. I may not reply straight away but will as soon as I can.


ja1484


Mar 6, 2008, 3:59 PM
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Re: [sterlingjim] Chain Reactor...unusual specs? [In reply to]
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sterlingjim wrote:
I was pretty worried I'd be swamped with PM's and emails once I started posting here on RC but that fear turned out to be for nothing. Folks are welcome to contact me with questions directly if they wish. I may not reply straight away but will as soon as I can.


And we're sure glad you did, because we're all better for it. It's nice to have a soft-goods authority on (relatively) regular patrol to give straight, correct answers.


(This post was edited by ja1484 on Mar 6, 2008, 3:59 PM)


AeroXan


Mar 9, 2008, 10:30 AM
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Re: [sterlingjim] Chain Reactor...unusual specs? [In reply to]
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so would the strength of one end to any other chain link be 17.5? what i'm trying to get at is does making one link drop the strength then adding more links doesn't drop the strength further?


Roasta


Mar 9, 2008, 5:52 PM
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Re: [AeroXan] Chain Reactor...unusual specs? [In reply to]
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AeroXan wrote:
so would the strength of one end to any other chain link be 17.5? what i'm trying to get at is does making one link drop the strength then adding more links doesn't drop the strength further?

Aero, I have been wondering this too.

For example if you had a length of rope with 4 knots exactly the same; does the strength loss (end to end) increase with more knots??

I feel that at the end of the day if each knot, or loop in this case, is exactly the same, all links are equally as weak - it therefore just increases your chances of something to fail. ie: more knots or links=more failure points.

If you used more links then there should be more stretch and possibly a higher breaking strain.

Not sure though.....


AeroXan


Mar 9, 2008, 8:23 PM
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Re: [Roasta] Chain Reactor...unusual specs? [In reply to]
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that makes sense to me. if the weakest point(s) in a chain has the same strength as other weak points, it would be up to chance/slight defects as to where it fails. so i guess in the case of the chain reactor, as soon as you add the webbing links into the system, the strength drops.

i suppose more links would make it harder to predict where the system will fail, similar to your more knots example. i think this is all correct but just want to hear it from someone who knows what they are talking about.


AlexCV


Apr 28, 2008, 2:05 PM
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Re: [AeroXan] Chain Reactor...unusual specs? [In reply to]
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You can probably model the chain reactor has containing three kind of "inks", the end where you girth hitch (it has different construction), the other end (it is loaded differently) and any number of identical loops. Whichever loop has the biner in it is effectively the "end-loop".

Pictured that way, the middle loops can be expected to behave in the same way no matter how many there are. So the length is probably not a significant source of strength reduction. The same way that a steel chain doesn't drop in WLL rating as it gets longer.


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