I once got my arm caught in an RC blade. Cut me about 1/4 inch deep through my flesh and in a line about 1 inch long. It was a 16 inch blade on a 65 CC engine. I stiched it up with a line of crazy glue and then went back to flying. I still have a scar, but I still have my arm.
I am sure that if the blade had hit bone it would have broken the blade and not my arm.
Are you talking about the prop on a fixed-wing model with an actual 65CC engine (probably gasoline)? Or a .65 cubic inch motor on a heli? There are model helis with 100cc engines but they're huge.