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  #1  
Old 10-13-2009, 07:19 PM
Bavafa Bavafa is offline
 
Join Date: Oct 2007
Location: Sacramento, CA
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Default none ferrous type cable/wire rope

Just wondering if any one knows of none ferrous type cable/wire rope that has decent (1500-2000 lb) breaking strength? I want to replace my shoulder harness cables that run to the back of the fues with a none ferrous type material and one way is to do it with slings/webbing but was hoping to find a place that I can buy aluminum or other type material to replace the existing 5/32" thick cables.

Thanks in advance
Mehrdad
RV7A
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  #2  
Old 10-13-2009, 09:50 PM
WingsOnWheels WingsOnWheels is offline
 
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Location: Plano, TX
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There are companies out there that make cables out of Kevlar and the like:

http://www.applied-fiber.com/our-product.html

Not sure why you would want to change though...
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Colin P.
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  #3  
Old 10-13-2009, 10:07 PM
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apkp777 apkp777 is offline
 
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Why do you want to change it? I think you need more that 1500-2000 lbs of breaking force. Impact crash forces being what they are, require much more than that. Your body can take a lot for a very short instant. Do some research on what is necessary. I'll bet 5-10,000 lbs is more closer to the need.
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  #4  
Old 10-14-2009, 12:37 PM
Bavafa Bavafa is offline
 
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I was looking at Spruce catalog and it listed the breaking point for the ends that gets attached to the 5/32" cable only at 2800 lb. Most climbing slings strength is about 4000 lb and I have taken many lead falls on those and have never broken. But if I can find a stronger one, then I surely would want to use it.
As for why I want to change, my magnetometer is installed behind the baggage compartment above the bell crank just below the top of the fuse. It is more then 18" away from the cables but the cables are pretty big and I am wondering if it is affecting the magnetometer (heading on my EIFS)

Mehrdad
RV7A
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  #5  
Old 10-14-2009, 12:46 PM
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apkp777 apkp777 is offline
 
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Got it. I think the concern with rope would be deterioration over time. Also, chaffing. You could probably put heat shrink tubing over it and limit both.
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  #6  
Old 10-14-2009, 02:03 PM
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jsharkey jsharkey is offline
 
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It's hard to beat the stiffness and resilience of steel cable. You don't want to end up on the end of a relative speaking, bungee cord.
Jim Sharkey
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  #7  
Old 10-15-2009, 01:02 PM
robpar robpar is offline
 
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Location: Vancouver British Columbia
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You could try Marine SS cables. They are 300 series SS and thus non magnetic. Breaking strength would be similar to steel and there are lots of end connections available.

Bob Parry
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  #8  
Old 10-15-2009, 01:43 PM
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Bob Kuykendall Bob Kuykendall is offline
 
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Location: Douglas Flat, CA
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Quote:
Originally Posted by Bavafa View Post
I was looking at Spruce catalog and it listed the breaking point for the ends that gets attached to the 5/32" cable only at 2800 lb. Most climbing slings strength is about 4000 lb and I have taken many lead falls on those and have never broken...
Mehrdad, I have pull-tested a bunch of climbing gear and also aircraft materials and hardware to tensile failure (search YouTube on "breakotron"). My take on this issue is that there are a couple of differences that makes comparing climbing slings to steel cables an apples-to-oranges kind of thing.

For one, climbing gear is generally rated to its breaking strength using three sigma (Aliens excepted, of course). That means that the actual breaking strength is usually very close to the rated strength, with little and sometimes negative margin. Aircraft hardware, on the other hand, is usually rated much more conservatively, with much wider margins to allow for manufacturing tolerances and wear and tear in service.

For another, the strength of a sling or runner is rated for the system consisting of a loop of material (two strands) plus the sewn or knotted joining that forms the loop. But the 5/32" cable is rated for a single piece.

If a single strand of 5/32" cable doesn't meet your needs, you can always go to 3/16" or 7/32". Have McFarlane swage on some nice terminals with their Kearney press and you'd be good to go.

One reason that I would not use nylon, aramid, Dyneema (tm), or Spectra (tm) for a seat belt anchor cable is that, as others have already observed, all those materials have much lower Youngs modulus than steel or aluminum. Of course, the seat belts themselves are nylon, that's unavoidable. But the more of those elastic materials you have in your restraint system, the more the system will stretch under load and the less margin you have between your body and the things you want to restrain it from.

Thanks, Bob K.
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  #9  
Old 10-15-2009, 02:21 PM
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dhammer dhammer is offline
 
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Default Why not

just use stainless aircraft cable?
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  #10  
Old 12-22-2011, 02:17 AM
Jef Vervoort Jef Vervoort is offline
 
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Location: Belgium
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Default non-ferrous type cable

Any practical news on this?
Has anybody found and used SS cables?
Or is there a way to neutralize the ferrous aspect of the original steel cables?
I'm also worried about interference with the magnetometers
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