We've done air dried ham for the last couple of years now - incredibly simple method:
Rub salt (normal catering) into every aspect of the meat, as much as you can to fill all crevices.
Pack meat into a container with at least an inch of salt under, over and to each side of the meat so the meat is not in contact with the sides of the container.
Leave in salt for 3 days every kilo of meat.
Take meat out, rinse off salt with cider vinegar
Hang meat in a meat safe, or wrap in muslin and hang.
Leave for 6-9 months
Don't panic at how disgusting the resulting meat looks.........
We leave the meat in the salt in our garage, then hang in the eaves of our barn.