While there might be other feasibility issues, pressession was accounted for.
The inventors solution included TWO counter rotateing flywheels...so the net external torque would be zero.

BTW, while as a concept it seems awsome I am suspicious that maby the magnetic bearings need superconductors. That requirement would drastically change the total mechanical efficiency calculation because you would need to account for energy cost of coolant for superconduction.

Also, the article was in Nexus Magazine...which is an entertaining read, but should be read with signifigant skeptical inclination because Nexus is very speculative IMO.