Vertical-Axis Wind Turbine

Wind mills work best in a steady wind. I live in TN wind is very gusty here. I use to fly kites when I lived in AZ wind is very steady continuous stream all the time there. Wind it too gusty to fly a kite in TN one minute wind is 10 mph for 30 seconds then dead calm for 20 seconds then 5 mph for 25 seconds, wind is up and down random speeds all day. In TN gusty wind for a wind mill will give you an average 0 to 15 mph might average out to about 7 mph. Those old wind mills farmers use to have to pump water will turn in a 2 mph wind and good up to about 20. Each type wind mill works best at certain wind speeds. Make sure you know your wind conditions then buy a wind mill to match it. I have a 40 years book that shows how much power a certain will mill blade produces this same information is probably online. Build a few small yard wind mills to test different designs. Every time wind mill diameter doubles the power triples. 4' dia produces 3 times more power than 2' dia. 8' is 3 times more than 4'. I don't remember math formulas to calculate power it will be online. Do google search for windmill calculator.