High-speed Desktop Fan
This fan runs on two power M size functions motors. I am not sure what the gear ratio is, but it is fast! [It spins faster than my Dad's 18-volt cordless drill.] It is equipped with a torque limiter, and is much faster than my original design which used a belt drive. [The battery box wasn't attached either.]The frame is a lot sturdier than I thought it would be too.