The laws of physics are in play here. First off, wind generates 5 watts of energy for 1 square foot at 10 mph. You can only capture 35% of that with the most modern design blade system. Let's call it 35% efficient, which that thing is not, so now you are down to 1.75 watts per sqft in 10 mph wind. So that 4' diameter wheel is 12 sqft x 1.75 = 21 watts. They mentioned linear, nope, wind is cube power, take that wind to 20-mph and you have 20/10 = 2 cubed (2x2x2) so now you're at 8x21 watts making 168 watts. To get to 400 it would take a 28-mph wind. But these things are wound so horribly bad it makes them terribly inefficient, they leave a huge gap between the rotor and the stator. A You Tuber that really researches these guys mounted one on a pole on the rack of his car and drove 60-mph and got about 2 amps flowing to his 12.2V half charged battery (25 watts). Of the many, many units he purchased and dissected, he did have one with a very well wound generator and it made spec.