I have the SSA's "Directory of Sailplanes" from sometime in the
1970s(?), which is a great resource for finding the basics of certain
models of sailplanes, but I'm looking for something more detailed on
glidepath control. For example, if I want to find out if the Slingsby
Kestrel uses flaps or spoilers, or I want to find out if the Phoebus C
uses flaps or spoilers, or...

Is there such a resource?

Ric T.