The First Certified Human Powered hover.
The Leonardo da Vinci series of helicopters were built at
CALPOLY San Luis Obispo starting in 1981 and ending in 1989. They were all 2
bladed, tip driven machines.
Leonardo I was a 50 foot radius rotor with a 30 foot per
second tip speed and large cord airfoils.
Leonardo II had a radius of 50 and 70 feet and was designed
for a 50 foot per minute tip speed.
Leonardo III was a 50 foot radius machine with a 50 foot per minute tip speed. It was much refined and flew for record in Dec. of 1989.