History
Helicopter with two side-by-side rotors on outriggers; it was flown inside a hall in Berlin in 1938.
The first practical helicopter
Helicopter with two side-by-side rotors on outriggers; it was flown inside a hall in Berlin in 1938.
Helicopter with two side-by-side rotors on outriggers; it was flown inside a hall in Berlin in 1938.