Abstract: A helicopter includes a main rotor guided and protected in minor impacts by a guide-ring. In selected embodiments, the rotor is powered by an electric motor employing a magnetic field generator carried by the main rotor and stator coils installed on the guide-ring. The helicopter's main rotor thus effectively functions as the rotor of the electric power plant of the helicopter. In selected embodiments, the rotor's blades are arranged so as to create an opening in the center of the rotor, allowing pilot ejection or deployment of a parachute capable of safely lowering the helicopter in case of an emergency.

Abstract: A solid material (12′) circumscribing an anode system (10) in an electrolysis apparatus is made from a mixture of cryolite and/or alumina (Al2O3), where the solid material (12′) contacts and surrounds the anodes (14, 14′).