Current Projects chat and miscellany

I see, so the balsa wood is a part of the frame, but won't that make it extremely heavy, given the large chunks of it used and therefore negating the benefit of using carbon in the first place ?

Although balsa is less common than rigid foams such as polyurethane or polystyrene, the use of a low density solid former is quite common in composite structures. Although I'm not aware of it's current use in any mass produced frames, it certainly crops up in disc wheels and some carbon rims, e.g. Lightweight. In the olden days, there were even some aluminium frames with structural foam reinforcement in areas subject to severe buckling stress, e.g. BB area on some Bianchi U2 frames. The foam or balsa provides a high resistance to compression, which if not resisted would allow the very thin walled skin to buckle. As such, using a sandwich structure of a skin which resists tensile loads in plane around a core which resists compression orthogonal to the skin plane can be a route to a lighter structure than a pure hollow structure, which has to have its skin thickened more to resist buckling than the tensile loading otherwise requires.

Honeycomb structures such as Aerolam are structurally similar, albeit that the low density compression layer is made from macroscopic cells and often (but not always) in the same material as the skin. At the more prosaic level, foam cored mounting boards made from thin layers of card sandwiching a layer of styrofoam are significantly lighter than a solid board of the same stiffness.