im about to sheet my wing on the ss 60 and suddenly had the feeling i was forgetting something. thinking back 20 years ago while building a ss 20 wing, i could have sworn i had to glue pieces of sheeting between the upper and lower spars ( grain running vertically) to create an i-beam effect for rigidity.
anyway, i checked the manual and its not there, nor is the material supplied. does anyone remember this practice and is it still used today? should there be flex in the wing to prevent them from folding or simply breaking? or, should i head to the local hobby shop for some balsa before i sheet the rest of the wing?
by the way, i think this piece was called "webbing", not sure though. thanks for your time and interest.

Its designed with out them but you sure could add
it to it if it makes you feel better. It will make the wing
stronger. Myself i would build it like its design and
fly the H*LL out of it. LOL

Ditto. If the engineers took it out, they must have had a reason, but there's no reason why you couldn't put them in for piece of mind.

Agreed, leave them out or add them if you'll feel better. And they're called "shear webs".
Dennis-

Yes they are shear webs and can be made of quite light materieal. On most planes a 1/16 inch sheet material is plenty. As to grain, it makes no difference whether the grain is vertical or horizontal. The actual sheer stresses are at a 45 degree angle to vertical and will switch directions 180 degrees as the strain goes one direction when the wings flex up and reverses to the other way when the wing flexes down. Check any strength and materials book on I beam design if you doubt this. The addition of the webs do greatly increase the rigidity of the wing with very little increase in weight.