For oil canning audio effect, I remember Gary Boggs had a video shot of a Schweizer 2-32 "canning" in flight. Here's one, but you might want to ask him directly https://www.facebook.com/NWSkysports...7722736246846/

https://youtu.be/g2FK1UyhF5E

Non-glider oil canning sounds that sounds like my last 1-35 flight:
https://youtu.be/U-MUdfq1BPI