As demonstrated in the animation you can see
here, the concept looks relatively simple. Their example has 4 arms, each containing 4 panels I suppose I'd call them, that pivot to minimize air resistance as the arms turn. When the panels are blown to be parallel with their parent arm, they lock against it so that they create a flat face to capture wind and spin the arm. once the arm is perpendicular to the wind, the panels should open out again due to the significantly-altered angle of attack from the wind. The animation has the panels staying closed to the arm much longer than I assume they would in reality.
If I was going to build this, I'd use symmetrical airfoils instead of the strange oblong slats the animation uses, and maybe 5 arms to increase overlap and smooth its motion. Plywood construction with some padding for panels hitting each other or the arms themselves, looking at maybe a 1-metre-by-1-metre design to see how it behaves.
Does this look workable? I don't like the way the panels snap back to their drag-reducing position after they're done capturing wind, it looks like it'd create a fair bit of stress for any sizable version. Especially considering how fast the panels would be spinning around in any decent breeze.
Of course I've never made a windmill of any type before, I'm just immensely curious in whether this design would actually work! I'm not looking for any real practical output, but I'm very curious as to how others here view this type of VAWT and any criticisms/suggestions they might have for actually constructing one.
