As far as I know, Da Vinci's helicopter design was simply that - thinking ahead of his time.
A quote from Wikipedia reference man-powered helicopter flight - the Da Vinci III was nothing like its namesake: -
"The first officially observed human-powered helicopter to have left the ground was the Da Vinci III in 1989. It was designed and built by students at Cal Poly San Luis Obispo in California, USA. It flew for 7.1 seconds and reached a height of 8 inches (20 cm). The second was the Yuri I in 1994, designed and built by students at Nihon University in Japan. It flew for 19.46 seconds and reached an altitude of 20 cm. Both were attempts to win the
Sikorsky Prize."
Link to article on Da Vinci III - or was that the Da Vinci II ??