I'm flying a couple of these at my store. They are 50v Ametek. They measure 4"X7".
I'm using my 49" plastic Jerry blades. Here are my wind test results.
10 mph 37.50 watts, 15 mph 62.50 watts, 20 mph 104 watts, 25 mph 156 watts, 30 mph 216 watts, 35 mph 280 watts and 40 mph 319 watts.
Those higher wind speeds don't have much value as usable wattage figure. I just tested that fast to see what the genny would do.
JK TAS Jerry