On Friday, April 13, 2018 at 1:20:47 PM UTC-7, John Foster wrote:
That’s part of the reason for the post. Our mechanic (A&P) has no experience with this type of construction and wanted me to find out what the known issues were, how to check for them, and ultimately how they need to be remedied. The glider has been stored indoors in his hanger the whole time, and about 15 yrs ago he did the annual inspection on it and it hasn’t been flown or out of his shop since. To my inexperienced cursory inspection, it looks OK, without any glaring obvious problems.

I would get in touch with a fiberglass repair expert such as Rex Mayes at Williams Soaring, and get an inspection procedure. The fact that it has not been flown is irrelevant; more important are the storage conditions, which sound excellent. Look for any evidence of mold or mildew (areas of dark coloration), which would make the glider unairworthy. You will need some sort of borescope or camera to do this. Rust on the metal parts is also evidence of moisture intrusion, another deal breaker. You can inspect the wings for any delamination by tapping all surfaces with a plastic-faced hammer; good areas will have a solid high-frequency knocking sound (caused by the bond reflecting back the tapping sound energy), bad areas will have a much softer lower-frequency sound. This principal is used in aviation ultrasonic bond testers (I designed and built this equipment in my former life).

Also, you didn't mention anything about damage history. I would pass on the glider if there were any major repairs.

Good luck!

Tom