M's Aircraft Photo Gallery
Pentecost Hoppi-Copter «Groupe
#Horace_T._Pentecost #prototype #contra-rotating_rotor #conventional_design #flat-2_engine
Pentecost Hoppi-Copter
 |
 |
| HX-1 Hoppi-Copter | HX-1 Hoppi-Copter |
|
|
| HX-1 Hoppi-Copter | HX-1 Hoppi-Copter |