Rib Construction

RIB FABRICATION

Theory

This post will eventually cover both the main rib and minor rib fabrication.  The main ribs are virtually the same as the original design except for the adhesive used and the circular cut outs in the foam core.  The minor ribs are used to lessen the tendency for the fabric to pull down between the main ribs when the main fabric is applied.  See the post titled "Internal Wing Structure" to see how the ribs are applied in the wing panel.
Note:  I do not discuss stamped aluminum ribs since the original foam/wood ribs are superior in strength and weight.  The other obvious advantage is that very minimal tooling is required to make wood/foam ribs vs aluminum ribs that would require expensive tool and die machining and stamping.

Jigs

A rib jig was finally constructed to aide in gluing the cap strips to the foam blanks.  This is not necessary and one could also use the original plans process of using finishing nails around the outside perimeter of the cap strip once the glue is applied. 

Sanding the spar notches in both ends of the ribs is described here.  A simple jig was required to get this done right.

Material and sources

Foam -

Glue -

Cap strips -

Gussets -

Process

Cutting foam rib blanks

Cutting gussets

Shaping gussets

Sanding the spar notch