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Carbon tow for fiberglass fuselage seam? - 7/3/2003 9:57:42 PM   
fw190



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From: Burbank, CA,
Status: offline 		This is something new to me, but it may be old for others... Instead of using fiberglass tape to reinforce the seam. I am trying to use carbon fiber tow. First, I lay up my fuse. Second, I cut of the excess fiberglass on the fuse halves (I do this just when the resin is somewhat cured).Third, I proceed to apply carbon tow and resin to the mating surface of the two halves ( I try and make sure that carbon is more into the fuse rather than the flange because it gets cut off anyways). Last, I close up the mold and dab on the seam.

So, would this method be strong enough instead of fiberglass tape or overlap method. I have done this on small parts such as wing tips and it worked rather well. I am however skeptical of using this method on larger fuses in the 1/5-1/6 scale warbirds.

Please let me know your thoughts and ideas, anyone use this method?

Thanks,

Vic

Here is the fin mentioned

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Carbon tow for fiberglass fuselage seam? - 7/3/2003 10:55:56 PM   
davidfee



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From: San Diego, CA, USA
Status: offline 		That looks interesting for making wingtips and such... a little more durable (and a lot stiffer) than just epoxy and microballoons/cabosil, etc. But for the fuselage seam I think you'd be better off with the fibers running across the seam, rather than along it. That is, use fused unidirectional carbon and cut it "across the grain." Or you could just use glass tape.

I don't think the overlap or step mold methods work well on really big stuff (especially if there is a sandwich involved) so taping the seam appears to be the way to go. Actually, a bias-cut tape would probably be the optimum.

-David

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SEAMS - 7/3/2003 11:14:20 PM   
TOYMAKER



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From: WAXAHACHIE, TX, USA
Status: offline 		On the fiberglass seams running length wise just use the f.g. (you can use c.f but f.g.is easier work with) Where the c.f shines is in the area of the fuse that would normally have a bulkhead. Using just c.f cloth or c.f tow around the inside of the fuse in these areas will strengthen it tremendously.

My fuse on my pattern plane is made completely of c.f. and coremat laminate and has no bulkheads/formers anywhere. An extra layer of 8mil c.f 1/2" wide at the bulkhead areas gives it the sructural strength needed that a former would provide.


Wayne

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Carbon tow for fiberglass fuselage seam? - 7/4/2003 2:40:07 AM   
FLYBOY



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From: Missoula, MT, USA
Status: offline 		As stated, tow run along the seam will do nothing to keep the seam together. You need something running across it. Use carbon BID if you want to, but make sure it goes across, not just along the seam.

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Carbon tow for fiberglass fuselage seam? - 7/4/2003 4:49:33 AM   
fw190



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From: Burbank, CA,
Status: offline 		Thanks for the response guys!

What's a carbon BID?

I did some testing on the wing tips, I consistently slammed one of them to my wooden workbench along its edge and it did not break on the seam at all. It broke where there were no carbon fiber tow. It broke on the fiberglass parts, close to the carbon tow but did no harm on the tow until I kept on doing it and then it broke on the carbon tow as there where not much support from the glass tip structure.

So, why do we need it to run accross the length? I think the tape method does exactly the same thing, it runs across the length? Though have a wider area for joint. Do you think the carbon will sheer (separate) from each other?

I got this idea from looking at Yellow Aircraft kits, originally they used fiberglass tow and polyester resin ( this is where they usually break so I never would try this method). But now they are using the carbon tow method with their epoxy fuses.

Maybe I will give it a try and see how it will work on the big fuses.

Vic

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Carbon tow for fiberglass fuselage seam? - 7/4/2003 7:49:46 AM   
winship


 

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From: Plainfield, IN, USA
Status: offline 		BID bi-directional or tow running in two directions within the cloth. The directions are refered to as the warp and fill. Warp is the long length as it comes off of the roll and the fill fibers are the ones that go across or side to side.

I agree with the posts above but give the tow method a try and keep us posted.

Winship

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Re: Carbon tow for fiberglass fuselage seam? - 7/9/2003 1:54:16 PM   
DanSavage



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From: Trabuco Canyon, CA, USA
Status: offline 		[QUOTE]Originally posted by fw190
This is something new to me, but it may be old for others... Instead of using fiberglass tape to reinforce the seam. I am trying to use carbon fiber tow.[/QUOTE]

My Yellow Aircraft A-4 has all the fiberglass seams joined using a FG tow in the exact same manner as you describe. This includes the main fuselage seam, main and cockpit hatches. None of the seams are taped.

It's held together pretty well at over 200 flights and 3 crashes over it's 3-year lifespan.

I believe that all Y/A FG parts are built this way. I'm not commenting about the pro's or con's of the practice, only pointing out that this is used in a commercial product(s).

Dan

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Carbon tow for fiberglass fuselage seam? - 7/9/2003 11:11:04 PM   
fw190



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Status: offline 		Dan, thanks for the response. I have only seen a few Yellow Aircraft kits. The P47, Spitfire both fiberglass tow and their new P40 using Carbon tow. Have not seen any jet kits. I did however see problems with the glass tow as they must have been in a rush putting the two halves together, where the glass tow was not sandwiched properly on the two halves.

Here is my test fuse with the carbon tow, its much stiffer in the seam area than using tape or the overlap method. I think that is a plus.

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< Message edited by fw190 -- Jul 9 2003 6:17PM >

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Carbon tow for fiberglass fuselage seam? - 7/9/2003 11:11:40 PM   
fw190



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Carbon tow for fiberglass fuselage seam? - 7/9/2003 11:12:58 PM   
fw190



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Carbon tow for fiberglass fuselage seam? - 7/15/2003 1:17:48 AM   
DanSavage



Posts: 578
Joined: 4/17/2002
From: Trabuco Canyon, CA, USA
Status: offline 		Hi Vic,

[QUOTE]Originally posted by fw190
Dan, thanks for the response. I have only seen a few Yellow Aircraft kits. The P47, Spitfire both fiberglass tow and their new P40 using Carbon tow. Have not seen any jet kits. I did however see problems with the glass tow as they must have been in a rush putting the two halves together, where the glass tow was not sandwiched properly on the two halves.

Here is my test fuse with the carbon tow, its much stiffer in the seam area than using tape or the overlap method. I think that is a plus. [/QUOTE]

I'm getting ready to make some molded parts myself and I was thinking of using TOW instead of tape.

How did you apply the TOW to the seam area? I read your first post, but I'm not too clear what you do with the tow that's on the flange. Doesn't this prevent the mold halves from fully seating? Or, does the excess squeeze back into the fuse out from between the flanges?

Nice model, BTW.

TIA,

Dan

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Carbon tow for fiberglass fuselage seam? - 7/15/2003 2:02:34 AM   
fw190



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Status: offline 		Dan,

I applied the tow on each half of the molds. I tried not to get too much of the tow into the flange area as it will get cut off anyways. Place the majority of the tow into the actual part. As you can see from my previouse pics that a lot of the tow are into the fuse not the flange. After putting the two halves together I press down on the tows to get them together and make a very good contact. If you can get tows to swirl together, it will be a very good bond, I don't think it will never separate in this area. The carbon tow is rigid compared to fiberglass tape, the glass fuse will have to break before the carbon tow will.

It is by far the easiest and cleanest method in seaming two parts together. Specially molded parts that you do not have access inside, just like the molded tips.

Vic

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Carbon tow for fiberglass fuselage seam? - 7/15/2003 5:04:34 AM   
DanSavage



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From: Trabuco Canyon, CA, USA
Status: offline 		Hi Vic,

Thanks for the prompt reply.

[QUOTE]Originally posted by fw190
I applied the tow on each half of the molds. I tried not to get too much of the tow into the flange area as it will get cut off anyways. Place the majority of the tow into the actual part. As you can see from my previouse pics that a lot of the tow are into the fuse not the flange. After putting the two halves together I press down on the tows to get them together and make a very good contact. If you can get tows to swirl together, it will be a very good bond, I don't think it will never separate in this area. The carbon tow is rigid compared to fiberglass tape, the glass fuse will have to break before the carbon tow will.

It is by far the easiest and cleanest method in seaming two parts together. Specially molded parts that you do not have access inside, just like the molded tips.[/QUOTE]

I think I understand now. So, you generally try to keep the tow away from the seam (flange) until the two halves are joined, then you "slide" the tow into position over the seam. Right?

Obviously, you impregnate the tow with resin before applying it to the inside of the molds, right?

This method sounds like the way that I'll be joining my parts, too. I'm preparing to make the molds for a composite twin EDF Sukhoi SU-27 Flanker and it has a few places inside where laying down tape would be pretty hard to do. Thanks for the info.

What size tow did you use?

As an I took the time to go over to your web site. Your body of work is impressive. I especially like the P-38 project. What size engines is it designed to use?

Dan

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Carbon tow for fiberglass fuselage seam? - 7/15/2003 9:13:11 PM