Fabricate Spar Tunnel - this section is under construction

 

The spar tunnel will enclose the spar on three sides with ¼” last-a-foam sheet as shown in the following photo.  First measure the three sheets required and glass them with BID on one side. 

¼” Foam test fit for the spar tunnel

It is best to test fit the foam with the spar installed.  Look at the following photo and notice that the spar tunnel has a lip at the top outboard edge.  This is to fit the shape of the spar.

Notice small piece of foam on the outboard ends of the top required to clear spar.

Create a radius where all foam corners come together, rough up the existing fiberglass with 120 grit sand paper, clean with acetone.  Cut little chunks of bees wax, soften with hot water and force into the spar bolt’s mounting holes.  Finally cover the entire spar tunnel with a single layer of BID extending onto the fuselage by at least 1.5” and let cure.

BID covered spar tunnel

Once the spar tunnel BID has cured, it is time to add the fiberglass structure that will tie the wing spar to the fuselage structurally. Use a sharpie to mark…..

Cardboard dam in place

 

Paper template for center section

Cured Spar attach structure

 

Trimmed and sanded edges ready for micro

Trimmed and sanded edges ready for micro

Trimmed and sanded edges ready for micro