No 12: In 1905 appeared his drawings of a helicopter with 2 large rotors turning in opposite directions, and a single tractor propeller, all driven through a shaft, spoked wheels and belts. The propellers were designed with the help of Victor Tatin and were formed of steel tubes, ribs, and fabric, weighing less than 9 kg each. The engine was tried with the 3 propellers and found inadequate and the helicopter was not completed.

   (Rotor diameter: 6 m; length: 12.5m: 24 hp .Antoinette V8)