How do I ensure a straight trailing edge when adding the top skin?
Use a long aluminum extrusion to keep the trailing edge straight. Home Depot sell these for screen enclosures. AeroCad supplies an aluminum T-bar with their wing cores for this purpose. Mask most of the extrusion with plastic shipping tape and leave a strip of aluminum exposed. Glue this strip to the bottom skin trailing edge. Use weights and clamps to get the trailing edge straight against the extrusion. Once the top skin is cured, use a very thin putty knife to pop the extrusion from the bottom of the wing.
