On Saturday, I was outside with my 30" windmill that has two blades that were perfectly cut on a CNC machine and a dc pump motor that is about 4 inches long and 3" in diameter. Anyways, it was really windy (probably about 30 mph) and I managed to put out 9 volts at 3.4 amps into 6 AA batteries. Based on 30.4 watts and my previous tests, that means the prop must have been spinning at 3,000 rpm!
Here is my power graph from my tests with my drill press.
I can't wait until this winter hits so I can see some 40mph winds. I may even go down to Presque Isle on Lake Erie on beach 10 with a short tower and dig it in to the sand for a few minutes. Of course, that's gonna be really cold with wind chills at -40....
