Structure/Material on Vasama II ( 2-seater )

I have had visions about the structure.

Since the plywood is relatively cheap here and epoxies are great glues. I see no reason why not to make a very cheap yet strong structure outa wood and enhanced with fiberclass and possibly some carbon here and there.

Metal ( steel/aluminium ) ) is vital in landing gear and rods, pedal some joints etc.

With the lightest 50 hp engine I think this could weigh 125-140 kg. Rotax ULS 912 powered version would have to be 175-190 kg at least. Jabiru 2200 povered perhaps 150-160 kg.

I have been thinking about shelled structure of very thin plywood and using ribs of thicker plywood. Sheets can be up to 4 meters long. Generally some ribs could be sandwich ply-foam-ply and other even metal-ply-metal...see the difference ?

Certainly these weights sound optimistic, but Colombani Cri cri proto only weighed 63kilos. I think the whole point in economical design is first to make it small and then create lite structure on it. To me seems like the fiberglass planes are not the lightest. Cri Cri was metal, but I assume since human powered planes are only around 30 kilos that some other ways are to reach low weight.