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Old Jul 10, 2012, 12:30 PM
Aurora Builder
United States, MD, Lusby
Joined Nov 2003
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Funky fabric

Guys, I can't figure out the reason for this fabric: http://shop.r-g.de/en/New-Products/T...c-107-g/m.html

Kevlar disser I understand. This I don't. It's more expensive than a pure carbon fabric. Just bling?
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Old Jul 10, 2012, 12:54 PM
Just fly it!
wyowindworks's Avatar
Cody, WY
Joined Nov 2007
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High stress or vibration exposed pure kevlar laminates are prone to delaminating. The problem is rarely seen in models because the stresses are low (walls buckle before other factors can play a part), the life span is low, and there is often a single layer. Adding carbon or glass to the weave improves the inter-laminar peel/shear strength. In theory you get a tough skin that isn't as prone to failing due to delamination.

It looks like this fabric has carbon in the warp and and kevlar in the fill. This makes for an unbalanced laminate unless multiple layers are used. It's a quirky fabric for sure. You'd get some serious warping and unbalanced torsional strength if you used it as a DLG wing skin or D-box.
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Old Jul 10, 2012, 01:10 PM
Father of Fr3aK, DLG Pilot
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I don't think you could consider using fabrics like this in single layers. If you're using multiple layers, then it could make a lot of sense.
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Old Jul 10, 2012, 01:34 PM
G_T
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Tailboom of a fuselage for instance. Backed up by HM carbon uni.

I just saw this fabric earlier today, and phoned Tom about it. I'd be curious to try a sample in a fuselage. It should present less of a resin barrier compared to the usual Oxeon spread tow fabric.

There is also another interesting new fabric on the R&G website - a wider spread tow Samurai fabric. Without sizing, it should be more conformable than the Oxeon fabric. And more frayable...

Gerald
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Old Jul 16, 2012, 08:26 AM
Aurora Builder
United States, MD, Lusby
Joined Nov 2003
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Interesting thoughts on the unbalanced kevlar/carbon fabric. I was thinking big picture with my question, not everything I build goes into a DLG

That 70 g/m^2 Samurai has been available for a while. It too doesn't make much sense-price wise its not cheaper than the 61 g/m^2 stuff and its not too much lighter than the 80 g/m^2 TexTreme, which is cheaper. Still, it does look pretty and might be a decent fabric to work with. Doubt it is more fray-able than Vlad spread tow or the Samurai fabric.

The 64 g/m^2 Oxeon is looking like the ticket to me though, although the binder weight still confuses me. I should just weigh my cut carbon (again) to see the difference for myself. I've been assuming the 9 g/m^2 binder is the plastic backing on the Oxeon TexTreme, but perhaps it is hot melt etc. keeping the spread tows aligned and thus ends up in the layup...
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Old Jul 16, 2012, 09:29 AM
G_T
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Let me know what you find out about that. Need to order fabric real soon... I'm running out too fast.

Gerald
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Old Jul 16, 2012, 10:30 AM
Aurora Builder
United States, MD, Lusby
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Gerald,

Looks like this answers a bit of the question: http://www.oxeon.se/uploads///downlo...forcements.pdf

Tom mentioned it in this thread: http://www.rcgroups.com/forums/showt...1426276&page=6

So it seems the fabric is closer to 89 g/m^2 and 73 g/m^2 for the new stuff. I will email r&g to get confirmation. It also appears that the 45-45 woven stuff never made it to market. That makes me inclined to go ahead and order the 64 g/m^2 rather than wait for the 43 g/m^2 stuff.
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Old Jul 16, 2012, 05:26 PM
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For a production builder, I see no benefit to 45-45 woven fabric anyway. My Fr3aK wing cuts in the 0-90 fabric are very efficient in terms of fabric wastage. Even the 45 degree triangle cutoffs that you have to make to start a roll off are not wasted since there are root and tip pieces that easily use that stuff up. The two main D-box pieces of carbon nest nicely end to end and fit diagonally across the meter wide fabric with a few inches to spare. Those few inches are used to make little rectangular servo doublers.
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Old Jul 17, 2012, 12:38 PM
Aurora Builder
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Agree Phil, its not much benefit if you have a large roll. Working with the 30/30 Vladimir spread tow is much easier from a pattern layout standpoint, but there are other downsides (fraying material). I also don't seem to be able to order any more!
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Old Jul 17, 2012, 12:50 PM
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Cody, WY
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45/45 materials can be very difficult to work with unless they have a heavy binder which makes them heavier and less pliable. 45/45 materials are woven like a large sock/sleeve and then split down the side and laid flat.
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Old Jul 18, 2012, 08:21 AM
Aurora Builder
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Quote from R&G on the TexTreme: "you will have 80 g carbon, and 9 g binder. You will use 57,5 g resin/m^2. Without binder you will use 66,5 g resin."
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