Originally Posted by
Hydromet
Interested in the structure of the fuselage. I looked at building a sailing boat which used a similar technique, except that the skins were fibreglass rather than wood veneer. However, the balsa was laid perpendicular to the outer veneers, ie, the grain ran from inside to out, rather than across, at right angles, to the skins. I couldn't see the structural advantage of doing it that way, and I've never seen it done that way anywhere else.
The balsa core does not add strength it keeps the outer and inner plywood or fiberglass at a fixed distance.
Same as the web of a H-beam keeps the lower and upper flange apart.
If you would replace the web by a massive fill with balsa it would be lighter but with same strength.
Putting the grain perpendicular to the outer layers makes the core more difficult to compress (dents) and the sheets of balsa can be more easily plied in the mould. And glue can penetrate into the pores reducing possible delamination.