Threw a wind generator together in 2 hours. I mounted a kid's cheap 24V electric scooter motor and rear wheel to a wood frame and screwed a ceiling fan blade to it. I tested it on top of a three story building and I could barely hold on to it while it spinning and giving 18V. The rear wheel connected to the motor with a timing belt, and was solid rubber, which turned out perfect (wheel dimensions matched the blade hub) for screwing into for the fan blades.
The cat is for scale. Unfortunately I don't have a picture of the side or back to show the motor.