went out with my instructor to get vortex ring experience , on return to airfield was on final and got us into it at 300ft ended up forward cyclic and whizzing along at 5 ft agl at 50knts for go round on next approach did exactly same again. i like a 50ft hover and lower it down gently. r22s can easily get into vortex, buy the time the vibrations have started its usually to late!