Originally Posted by
tdracer
And of course, there is that always present problem with drag (and hence the thrust required) going up with the square of the speed. So even if you get very good SFC numbers, it's still going to take a lot more fuel to go that fast relative to today's ~0.8 Mach.
While subsonic parasitic (skin friction and pressure) drag goes up with the square of speed, induced drag goes down. In the transonic and supersonic rage, shockwaves completely change this relationship.
In any case, crucial with supersonic engines are the inlet design (turning speed into pressure without getting shockwaves into your fan / compressor) and having an exhaust speed which is significantly higher than your flight speed, which includes exhaust design. I do not see how their concept addresses this...
The only advantage I see to coupling the compressor and turbine electrically instead of mechanically is being able to spool the engine up faster and as an alternative to a geared turbo fan (have them run at different speeds). But then the latter is mostly useful for high bypass ratio engines which cannot generate the exhaust speeds for supersonic flight...
But maybe I am missing something.