Those lift fans seem way too small to provide wnough lift. F35b lift fan for example has diameter of 1.3 meters. And most of its lift comes from fast moving edges of the blades. One might have issues with just making fan turn faster as supersonic blade tips might lose efficiency.
Frankly, one would expect two fans of 1 m in diameter, each, if they are to approch the kind of lift a single 1.3 m diameter fan can produce.
Plus a flimsy, moving rotatable power axle arm feeding the fan might not be as efficient as a big, fixed axle that is built into a plane.