In the process of designing, building and testing a model wind turbine to generate electricity and compete in a KidWind Challenge it can be simple or complex. I believe the time, effort and learning will be proportional to the simplicity or complexity of the design.
The KW process starts out pretty simple. Make some blades. Attach the blades to a shaft. Gear up the shaft a bit to increase the speed the generator turns at. Connect the gears to a small DC electric motor and you are in business. Fifth graders on up handle these tasks pretty well and have a lot of fun in this learning process.
If you choose to take it up a notch read on.
In competition about one third of a KW Challenge points is about the electric energy (Joules) your turbine produces. Produce one volt at one amp for one second and you have just made yourself one Joule of electric energy. Who knew? Who cares??