[HX-1]
Manufacturer: Hoppi-Copters Inc. [USA]
First flight: 1940s
Dimensions: Length: m (  ft  in )   Rotor diameter: 3.66 m ( 12 ft 0 in )   Height: m (  ft  in )
* two contra-rotating rotors, extremely hard to control,

Pentecost Hoppi-Copter : Backpack helicopter

Pentecost
HX-1 Hoppi-Copter
Pentecost
HX-1 Hoppi-Copter