It looks like the number of manufacturers doing composite designs and kits in particular has declined sharply the past few years. There have been a few upstarts like Vision / Personal cruiser, but not a whole lot else. One of the things that fails to excite me regarding designs like the vision, is that they seem to replicate sheet metal design except for the substitution of aluminum ribs with composite. The wing design on the vision is my idea of a mess... So many ribs, so many joints and potential leak paths to debug if there is an issue...
So here is a thought: Provided one has a sufficiently large work area... Why not manufacture a single piece wing spar which fills a large % of the wing cross section. I was thinking of a flat bottom plate with a trapezoidal hat on top. The top section could be molded over a male positive form with acceptable draft angles and then bonded to the bottom plate section with final overlapping bid plies to prevent separation of the bond line and improve transfer of the shear loads. Worst case, one could do 2 trapezoid sections, top and bottom with the bond line in a plane with minimum shear loads. This should yield a light spar with high bending and twisting strength and hollow in the inside for fuel storage. It would be easy to add some baffles on the inside to prevent fuel sloshing around and if one adds some dihedral that also makes it easier to access the full fuel volume.
For the wing surface, bond fuel resistant foam to the outside of the completed spar, shape appropriately and do a Rutan style 2 bid layup. Is physical size the only reason why something like this is not commonplace ?
So here is a thought: Provided one has a sufficiently large work area... Why not manufacture a single piece wing spar which fills a large % of the wing cross section. I was thinking of a flat bottom plate with a trapezoidal hat on top. The top section could be molded over a male positive form with acceptable draft angles and then bonded to the bottom plate section with final overlapping bid plies to prevent separation of the bond line and improve transfer of the shear loads. Worst case, one could do 2 trapezoid sections, top and bottom with the bond line in a plane with minimum shear loads. This should yield a light spar with high bending and twisting strength and hollow in the inside for fuel storage. It would be easy to add some baffles on the inside to prevent fuel sloshing around and if one adds some dihedral that also makes it easier to access the full fuel volume.
For the wing surface, bond fuel resistant foam to the outside of the completed spar, shape appropriately and do a Rutan style 2 bid layup. Is physical size the only reason why something like this is not commonplace ?
