Electric vehicles are DC permanent magnet motors. The magnetic field is generated by permanent magnets, and the generator does not require winding excitation. The simplest way to convert a battery car motor into a generator is to use PVC water pipes cut into trapezoidal shapes with curved surfaces to serve as fan blades. Fix the motor spindle on the iron pipe and add a guide rudder behind it. Finally, the whole thing is connected and fixed through the rotating shaft, and then it can generate electricity.
Fan principle, however, in order to have a certain strength, the closer to the root of the fan blade, the thicker it becomes. Made of fiberglass. The reinforcing ribs made of fiberglass are placed in the mold and then injected with resin to form. The small air leaf has a solid structure, and the large one has a hollow structure. The hollow part of the large fan blade is almost half a cylinder. It is not an exaggeration to say that it is based on the principle of an airfoil. The installation angle of the fan blades is generally adjustable. The wind turbine has a complete constant speed device, and a device that automatically brakes, then turns, and finally rotates again when the wind direction changes. Don't do your own research and development. If you want to make a finished product for sale, just buy one and then reverse engineer it. You can search for "Manufacturing Process of FRP Fan Blades".