vane - Any of several usually relatively thin, rigid, flat, or sometimes curved surfaces radially mounted along an axis, as a blade in a turbine or a sail on a windmill, that is turned by or used to...
the blade is called rotor blades
The rotor blades on top are called Main Rotor Blades, because they are the main source of lift for the helicopter. The smaller rotor blades on the tail are called...