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Info torsional fuselage composite asymmetric

Info torsional fuselage composite asymmetric

(OP)
Hi

I wonder about torsional strength of a fuselage for a light airplane with a big asymmetric hstab all on
1 side. The fuselage sizing is like any fiberglass sailplane, about 9in near vertical. So with hstab and elevator it's pretty asymmetric and causing a torsional effect.

Doing it in composite I got a first analysis that show lot of UNI ply over few 45 bias fiber, making the overall a thick layup. Can I decreased this layup by going with a more semi monocoque structure of hat stringer all around of many bulkhead ?

And if the stringer will be all in 45 or with uni tape too ..?

Thanks

RE: Info torsional fuselage composite asymmetric

Most fiberglass sailplanes have a lot of glass going in the 45-45 direction in the aft fuselage for torsional stiffness, typical layups in the real world are at least 6 layers of glass Usually with the outer layers going straight then the middle layers going 45-45 and the inside layers going straight.
The early glass sailplanes had, inverted V or top hat section ribs, and stringers with 5 layers of glass. This was found to be too labor intensive to manufacture those fuselages, (They also broke a lot in landing incidents.) , so a later scheme to prevent fuselage deformation was to manufacture a + from PVC foam glass sandwich and use this for two purposes, one to hold the joints steady in the mold during gluing, and the other to stabilize the fuselage cross section, and prevent it from going out of round. Another system for stiffening the fuselage was to lay 3 to 4 layers of 3" wide unidirectional tape at 2'-0" intervals in the hoop direction down the fuselage. This may not answer your question completely, but it may point you in the right direction.
B.E.

You are judged not by what you know, but by what you can do.

RE: Info torsional fuselage composite asymmetric

maybe it's time to revisit geodesic structures, a la Barnes Wallis, like the Vickers Wellington

another day in paradise, or is paradise one day closer ?

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