digsy

Does anyone have experience of producing a built-up fuselage using carbon fiber tape/strips for the longerons etc instead of balsa ?

I'd like to use white foam and CF tape with resin to make the built-up fuselage and then remove the white foam using acetone.

I'm sure someone has done this before so I'm wondering what the advantages/disadvantages & pitfalls are.


Thanks,
Nathan

BMatthews

It'll come out heavier than if you used a female mold. This is mostly due to the need to use more resin with this method to provide a buildup on the outer surface to "clean up" the weave and laps and provide something to sand to a smooth and fair shape. When I do this with fiberglass and epoxy for cowls I use a final coat of resin thickened with micro glass balloons for a sanding layer. Thicken it so it's brushable but builds well. You need this buildup because you don't want to sand down to the fiber and cut through the very fibers that are providing your strength. A small spot here and there is not going to ruin it but if you sand thruough the surface fibers in too many spots then you'll loose a lot of your strength.

digsy

Whoops - I guess by built-up fuselage I meant stick & truss ? (like not a stressed skin structure)

Nathan

BMatthews

Oh, you mean like stick and tissue but in carbon? Or a better description would be like a big Guillow's half shell but in carbon?

I suspect you'll be a pioneer if you try this. But I have to say that using round stock carbon rod or flat rectangular rod for longerons would be interesting. And if the formers were formed of foam and carbon cloth vac bagged sandwich you would have a very high tech stick and tissue buildup. Kevlar thread could be used for the diagonal cross bracing.

But I have to ask... WHY?

digsy

Well like the SIG Seniorita fuselage.

I was thinking it would result in a very light fuselage (I'm not so worried about strength - its for an electric thermal glider project)