Note that the main wing spar design uses tapered capstrips made from sheared 1/8" 2024-T3 sheet. This is more costly and labor intensive for kit fabrication than using bar stock or extrusions as other kit designs do but makes for a more uniform spar that is lighter and stronger with minimal load concentrations. There are only 2 NAS bolts attaching each main spar to the center section allowing for quick and easy removal of the wings. The attachment is very strong and there has never been a failure in 36+ years and over 100,000 flight hours.

The largest rivets used in the airplane are also shown here. The first 20" of the main wing spar use 5/32" diameter rivets which can still be driven with a standard 3x rivet gun. Everywhere else in the airplane smaller, easier to drive, 1/8" or 3/32" diameter rivets are used. By using smaller rivets, but more of them, a few scattered poorly driven ones will not hurt the structural integrity of the aircraft. This is an example of the "design for homebuilder construction" principal used throughout the airplane. This principle is what makes the Mustang so easy to build yet so strong.