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Building Tips and technical articles. => Building techniques => Topic started by: steven yampolsky on March 26, 2013, 02:51:04 PM
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Has anyone tried building a fuselage out of carbon fiber(no balsa sandwich, straight CF). How many layers did you use? What type of weave pattern and how thick/heavy was the fabric?
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No, but here's what would happen if you tried:
Carbon fiber is very strong for its volume, so if you go and calculate the amount you need to make a strong fuselage ignoring the local strength you need to keep the sides from caving in, you come up with "not much". Then you make your fuselage, and as soon as you pick it up the sides under your thumbs go "bworp*" and cave in. To see this effect, pick up an empty pop can and squeeze gently.
So you make the sides with two or three layers: either one layer of CF with enough balsa inside to prevent the "bworp", or CF, balsa or foam, then CF, with each CF layer being half of what you used in the "bworp" example. Result: a fuselage that is strong in all ways**, light, and insanely more difficult to build than just using balsa.
*http://en.wikipedia.org/wiki/Don_Martin_%28cartoonist%29 (http://en.wikipedia.org/wiki/Don_Martin_%28cartoonist%29)
** when you squeeze it it will go "fleen", but silently because it is not moving.
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Maybe Fred Cronnenwett and/or Grant Hiestand could answer with their experience of forming molded fuselage shells and seaplane floats from woven carbon cloth.
I know their results are quite impressive. Strong and light. Formed in a female mold.
Keith
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No, but here's what would happen if you tried:
Carbon fiber is very strong for its volume, so if you go and calculate the amount you need to make a strong fuselage ignoring the local strength you need to keep the sides from caving in, you come up with "not much". Then you make your fuselage, and as soon as you pick it up the sides under your thumbs go "bworp*" and cave in. To see this effect, pick up an empty pop can and squeeze gently.
So you make the sides with two or three layers: either one layer of CF with enough balsa inside to prevent the "bworp", or CF, balsa or foam, then CF, with each CF layer being half of what you used in the "bworp" example. Result: a fuselage that is strong in all ways**, light, and insanely more difficult to build than just using balsa.
*http://en.wikipedia.org/wiki/Don_Martin_%28cartoonist%29 (http://en.wikipedia.org/wiki/Don_Martin_%28cartoonist%29)
** when you squeeze it it will go "fleen", but silently because it is not moving.
and you can use types of foam for the laminate too. The CF fuse is very heavy if you only use CF
Randy
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I think Windy built a Miss Ashley using a hollow carbon fiber fues and wing. Midgely(?) (sp) did the moulds. I remember looking closely at the plane at Brodak. Saw the carbon fiber webbing. It was a number of years old at that time and the dope had settled. A NY flyer is casting fiberglass fueses and wings. Sorry. Senior moment. I am forgetting his name. The results are light and rigid.
I believe Jose Modesto is making airplane parts from casting fiberglass.
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It's not the carbon fiber that is heavy, it is the resin that gets heavy.
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No, but here's what would happen if you tried:
Carbon fiber is very strong for its volume, so if you go and calculate the amount you need to make a strong fuselage ignoring the local strength you need to keep the sides from caving in, you come up with "not much". Then you make your fuselage, and as soon as you pick it up the sides under your thumbs go "bworp*" and cave in. To see this effect, pick up an empty pop can and squeeze gently.
So you make the sides with two or three layers: either one layer of CF with enough balsa inside to prevent the "bworp", or CF, balsa or foam, then CF, with each CF layer being half of what you used in the "bworp" example. Result: a fuselage that is strong in all ways**, light, and insanely more difficult to build than just using balsa.
*http://en.wikipedia.org/wiki/Don_Martin_%28cartoonist%29 (http://en.wikipedia.org/wiki/Don_Martin_%28cartoonist%29)
** when you squeeze it it will go "fleen", but silently because it is not moving.
Jose Modesto has built a few.
Derek
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Looking at the edges that are visible in those pictures, it looks like he's doing a 2- or 3-layer layup, although not with either the balsa or the foam that I was babbling about. I wish he (or Howard Rush, or someone else who's done more than building car parts from fiberglass) was here to comment on what was done, since he's actually done this.
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I love that fuselage... wa$ wondering how much it would co$t to have one of those made :)
Marcus
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I love that fuselage... wa$ wondering how much it would co$t to have one of those made :)
Marcus
Send a private message to Jose Modesto.
Derek
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Send a private message to Jose Modesto.
Derek
Thanks Derek
I had no idea they were actually available...
Will do.
Marcus
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Has anyone tried building a fuselage out of carbon fiber(no balsa sandwich, straight CF). How many layers did you use? What type of weave pattern and how thick/heavy was the fabric?
I ask a little more:
1 _ Type of fabric in g/sq.in. or g/m2 and where we can buy it
2 - Type of epoxy system resin
3 - Type of mold and use of vacuum
4 - Cure with or without hot in a oven
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I ask a little more:
1 _ Type of fabric in g/sq.in. or g/m2 and where we can buy it
2 - Type of epoxy system resin
3 - Type of mold and use of vacuum
4 - Cure with or without hot in a oven
and a few more:
5) how many layers
6) what type of weave for each layer. I am thinking the top layer might need a special weave.
7) How do you join fuse halfs?
8) are the cutouts for the wing, cowl, stab, etc done before or after?
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I should place this great book in the Classifides.
Loaded with information on Compisite methods of building.
Charles
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Guys I'm on a Caribbean vacation will post later the beach is great,today is a great flying day here.the trade winds are down.
Thanks D for posting photos.
SV22fuse as shown from outer layer in. .5 glass cloth,2.4 oz CFC,1/32" pre molded balsa shell,.2CFM with 2.4CFC as doubler.
Fuse as shown weight 6.5oz the fuse is made in right and left sides assembled in the mold. The only formers are for the take apart hardware.
The SV22 fuse is molded in female molds under vacuum pressure.
The .5 cloth on the exterior layer Is used to create a very smooth outer surface. NOTE the fuse can be painted in the mold you can also paint the trim.
Steve this section page 3 will give some info. Also do a search in Electric section I have posted fuse construction page 9
Jose Modesto