What are the “V”-shaped layups over the wing attach points for?
The “V”-shaped layup over the wing attach points are reinforcements to help collect the load and transfer it to the center spar. In Chap. 19, p.6, Fig. 32 the 2″ wide layup across the corner is at a point of stress concentration, and your paint might crack there if you leave it out. The 12″ layup in the valley is where the maximum bending and drag (pushing backwards) loads are. The drag loads are compressive loads which tend to buckle the skin. A little extra skin thickness at this point provides an extra safety factor when exceeding Vne.
