They show two versions in the diagram. One has conventional jet engines inside the saucer, but the other one has parts of the whole saucer spinning so the fuselage works like an engine. They have compressor blades, burners and turbine blades inside.
That is interesting, and I haven't run into anyone pointing out this distinction or doing any analysis on it. I don't know what limits the aerodynamics but potentially you could get really high amounts of thrust, something more comparable to a helicopter than a Harrier. You could run into big problems with gyroscopic effects as well, maybe you would need two "spools" that counter rotate.
That second one, from a basic analysis... it isn't really much different to a helicopter in its principle, given the size and spacing of the outer turbine blades. An obvious concern given the similarities to a helicopter is how well can something with a rotor the same size and an even larger jet engine stay in the air if it has a smaller fuel tank?
As for the design they actually constructed, it seems like it would be a lot more feasible with modern technology. It's not clear to me that there's any actual advantage to building a flying saucer though, other than novelty.
That is interesting, and I haven't run into anyone pointing out this distinction or doing any analysis on it. I don't know what limits the aerodynamics but potentially you could get really high amounts of thrust, something more comparable to a helicopter than a Harrier. You could run into big problems with gyroscopic effects as well, maybe you would need two "spools" that counter rotate.