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  #11  
Old 12-22-2011, 07:17 AM
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Mel Mel is offline
 
Join Date: Mar 2005
Location: Dallas area
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Originally the RV shoulder harness used seat belt material further back into the tail-cone. The reason for the change was elasticity. The seat belt material had too much "stretch" and made the shoulder harness essentially ineffective.
Mine are stainless and don't seem to affect my compass module at all.
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  #12  
Old 12-22-2011, 08:25 AM
Danny7 Danny7 is offline
 
Join Date: May 2008
Location: central oregon
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mehrdad try these guys, they should have some stainless cable you could use.

http://www.acmerigging.com/

it is used a lot for railing restraint, called decorative but there shouldn't be a problem finding proper strength sizes
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  #13  
Old 12-22-2011, 09:07 AM
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jjconstant jjconstant is offline
 
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I went through this process for a different reason. I used inertial reel shoulder harnesses and the inertial reel needs to be mounted securely so that there is no slack in the entire system. The standard Vans cables were too long and would have flopped about midway between the baggage bulkhead and the seat back, providing so much slop that the inertial reels wouldn't have locked until after my face was through the panel

I called Vans and they suggested that I go to a marine rigging place and get some stainless cable and have them cut it and swage it to whatever length I needed. That's what I did. My magnetometer is also back there and there are no issues.

All Best

Jeremy Constant
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  #14  
Old 12-22-2011, 09:47 AM
David Paule David Paule is offline
 
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Location: Boulder, CO
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Dyneema rope will do well. It's a low-stretch marine rope used on sailboats and other applications. Although it's low-stretch, it still stretches more than wire rope. The numbers for Young's modulus are about 4 or 4.5 million psi for the Dyneema and about 11 or 12 million psi for the steel cable, so if you double the nominal diameter for the Dyneema, you'll be okay for low-stretch.

And Dyneema's strength is so great that it simply won't be an issue. It's very light. I think it'll float.

The caveats and gotchas are:

1. The Dyneema is slippery and knots aren't reliable. Worse, they'll break at relatively low loads. Only a proper splice should be used, such as this one, which is fun to make:
http://www.neropes.com/SPL_12Strand_...ceBrummel.aspx

Personally, I can't splice this if it's thinner than 1/8" thick, and that's difficult. Thicker is easier.

Incidentally, the buried end needs to be well-tapered and buried at least 44 times the diameter. The easy way to taper it is to bring it out of the cover (bunch up the cover) below where you want the end to be, cut the taper on the individual strands, and then pull the cover back over them.

2. The Dyneema is sensitive to stress concentrations and won't develop its strength around sharp edges or small radius objects. Ideally you need something like 8 times the rope diameter for the diameter of the object the Dyneema is wrapping around. Smaller gives proportionally lower strength, and since the rope strength in the oversize diameter is high, you might be able to get away with it in some applications.

3. Dyneema creeps. If there's a steady load it'll gradually stretch. You wouldn't use it for control cables, for example, since they generally need tension.

4. It's pretty abrasion-resistant and fairly UV resistant. In both cases it'll wear or soften on the exposed fibers and you can see and feel that. But it's not as durable as wire rope in that regard.

5. Being a low-stretch rope, it doesn't absorb much energy when loaded. You would not want to use it for climbing, for example, if you fell, the shock would be very severe.

You can get Dyneem from places like http://www.apsltd.com/c-1492-amsteel-blue-samson.aspx, under the trade name "Amsteel Blue."

It's good stuff, when used with knowledge of its characteristics.

Dave

Last edited by David Paule : 12-22-2011 at 09:48 AM. Reason: Added point 5.
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  #15  
Old 12-22-2011, 10:18 AM
jchang10 jchang10 is offline
 
Join Date: Nov 2005
Location: San Francisco, CA
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I have been trying to calibrate my dynon skyview compass without success. My best guess now is that my steel seat belt cable is the culprit. the adahrs/magnetometer lies about 8" above the steel cable.

Update: well, i removed the cable and am still getting the darn error. i seemed to have ruled the cable out.
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Last edited by jchang10 : 12-22-2011 at 07:26 PM.
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  #16  
Old 12-22-2011, 11:20 AM
JSBergen JSBergen is offline
 
Join Date: Dec 2010
Location: Apple Valley, MN
Posts: 22
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I asked a similar question about a week ago but due to the trim cable location on an RV9A relative to the Garmin GMU-44. I have been told that you can demagnatize the cables (degausse) sp? either with a permanent magnet or with an electro magnet. I am still researching......

Regards,
Jamie
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  #17  
Old 12-23-2011, 12:52 PM
Jef Vervoort Jef Vervoort is offline
 
Join Date: Feb 2008
Location: Belgium
Posts: 5
Default non-ferrous type cable

Thanks for that info, Jchang, I have also two Skyview Adarhs in the proximity of the cables, at about the same distance. I'll try to calibrate with the Van's cables.
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  #18  
Old 12-23-2011, 12:56 PM
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Bill.Peyton Bill.Peyton is offline
 
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Location: St. Louis, MO
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I was at West Marine today getting some supplies and found that they will sell you SS wire rope and swag the fittings on in the store! Here is the link to there catalog page.
http://www.westmarine.com/webapp/wcs...classNum=50090
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