Hand made balsa ribs

I decided to resigned the structure of wing panel around the rib's airfoil. Instead of the two bottom spars I opted for a conventional top and bottom spar with a sub-spar in front to share the covering and add some strength:


using my CAD program I created a new 3D object of the rib with 1/8"x1/4" main spars (top and bottom) at the CG location, 1/8" square sub-spar, 3/16" square leading edge, and a 1/8"x1/2" trailing edge.

The CAD files can be downloaded from GrabCAD here.

I printed the template pair on my 3D printer using PLA and used them as a sanding template for creating two stacks of ribs for the two wing panels:


Preparing the stack with 1/16" light balsa:


The stack after sanding and cutting slots for spars:


Finished rib set for one wing:


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