Can anyone recommend good download sites for open-rocket/rocksimpro design files?
The only place I have ever found a collection of Rocksim files is at https://www.rocketreviews.com/, in their Rocksim Library loaction.
Some companies post Rocsim models for their kits, e.g., LOC and Madcow. What are you looking for?
Is rocket reviews still an active site?
CMASS is a chartered section (#464) of the National Association of Rocketry.