Carbon/Kevlar or Carbon/Fiberglass sock - RC Groups
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Feb 08, 2011, 04:52 PM
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Carbon/Kevlar or Carbon/Fiberglass sock

I am about to sock my new speedo fuse and can't decide what type of sock to use. My thinking so far is the carbon in each sock provides strength and both fiberglass and Kevlar have their advantages and disadvantages

Kevlar - would provide added flexibility and durability but my understanding is that it will also increase weight and use a higher volume of resin

Fiberglass - would not be as durable but would be lighter and easier to work with

I am only just starting to use composites and this will be the first time I have used sock. Any comments relating to how to work with the different products or addvice from those who have socked their speedo would be great

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Feb 08, 2011, 07:23 PM
Come out swinging
sporter's Avatar
The isn't really enough information in your post for me to comment, other than I need more information. Fuse size, etc.

I work with the braided sleeves alot. I've used them all. One major consideration is that the braided sleeves offer excellent torsional ridgidity and pretty good hoop strength, but in the long directions you'll need more. Depending on the size, add something with the fibers running parallel to the length, in addition to the sleeve. This makes it tough, because most people want the nice biaxial braid to show on the outside. This means the long parallel fibers need to be on the inside of the braid. Tough layup. Easy with lost foam though.

Again, there are lots of variables.

Feb 08, 2011, 07:26 PM
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David Forbes's Avatar
Not sure what a Speedo is (I'm thinking Borat here), but I'm assuming you're pulling a sleeve over something and soaking it with resin. Are you going to have to sand it after that? If you are kevlar might not be the best choice even though it is lighter and in some ways tougher than FG. It makes the most gawdawful fuzz when sanded.
Feb 09, 2011, 11:47 AM
Just fly it!
wyowindworks's Avatar
It's a tough call. Just pick one an use it.

If the socks have the same weight, the kevlar one will end up heavier. Kevlar has poor compression strength, but it could be overcome by adding some UD carbon down the length of the fuse before applying the sock. The kevlar will also add more stiffness due its greater laminate thickness and higher tensile modulus.

As others have already said, adding a sock isn't the best use of the added fibers since most of them are misaligned with the applied forces. If the manufacturer of the Speedo cheaped-out and put all the glass on 0-90 then adding the sock will be an improvement. If they put it all on +/-45 then adding some UD material down it's length will really help. Looking at how they break will often clue you into how the lay-up was done.
Last edited by wyowindworks; Feb 09, 2011 at 11:56 AM.
Feb 09, 2011, 03:43 PM
Registered User

They are cheap and very thin, often splitting down the seam or cracking around the wing saddle.

I have decided on carbon / fiberglass as it is easier to work with should end up lighter and will work

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