[sdfaf]

It doesn't really seems as simple or obvious as you make it seem. The engineering that went into building those wheels with the blades in the middle seems quite impressive and not something that your average joe would be able to design and build.

[bri3d]

The build process looks quite straightforward to me; it's a hubless wheel (common) with a brushless outrunner (common) screwed into the middle.

The idea is certainly novel as far as I know, though.