On Sunday, August 4, 2019 at 6:26:30 PM UTC+1, wrote:
On Tuesday, July 30, 2019 at 11:00:34 PM UTC-5, wrote:
Can anyone tell me specifically how to tell how closely a wing is following its intended shape or to know if it has "issues"? Also, if I'm sanding, polishing or refinishing it, how do I accurately correct for any deficiencies? Asking for a friend... : )

My primary reason for starting this thread was to help me know how to evaluate whether an FX-67 winged glider has suffered from "spar shrinkage" and if so, how much and how badly it will impact the performance. I've heard so much about and that it can profoundly decrease the performance so I'm trying to figure out whether to worry too much about it. As a relative newcomer to working with composites I'm not sure I could actually fix it...or might make it worse.

Thoughts?

If its spar shrinkage you are worried about you don't need a template; if it is significant then it will be easily visible and palpable along the spar cap line. If you can see that and feel that it is worth the effort for cosmetic reasons you could fill and smooth that area. It is not likely to be worthwhile worrying about it aerodynamically on an old Wortmann FX-67K-150/170 wing as that aerofoil has an inherent property of rather early airflow separation on the top surface. It was, IMHO, not a very good section as shown by the fact that ASW 17s and 20s with older 1962 Wortmann sections performed better than all the comparable gliders with 67 sections and also were not so susceptible to bugs and rain