A helicopter with a rotor with two broad, propeller-driven blades, built by Ludwig Ös (or Oes) in 1910, in Bekescsaba in what is now Hungary.
Ös 1910 helicopter
A helicopter with a rotor with two broad, propeller-driven blades, built by Ludwig Ös (or Oes) in 1910, in Bekescsaba in what is now Hungary.
All Aero 