Smallest One Man Helicopter

I've heard the counterrotating blades idea before... in connection with a man made "UFO" designed around 1955. I see it works.

"The GEN H-4 requires approximately 30-40 hours to assemble the pre-manufactured parts. " - byu

Empty weight? Max takeoff weight? Endurance? Cruising speed? Ceiling? VNE?

155 lb (70 kg) 420 lb (190 kg) Approx. 60 min. (Depending on payload) 55 mph (100 km/h) 10,000 ft (3,000m) (estimate) 120 mph (200 km/h)