The engine was a turbojet that had an annular bleed that coalesced into 6 x 9" diameter pipes which took on a semi-helical flow path to an area just behind the turbines. At low mach numbers, the engine's inlet guide-vane acted like any other, but as the speed increased, it adjusted the pitch on the guide-vane causing the airflow to take on a helical pathway through the engine and effectively reduced the effective angle-of-attack on the blades (the aim of this was to reduce turbine inlet temperature).
As the speed continued to increase, the bleed-bypass system would come online and begin routing the airflow around the engine and into the afterburner. The afterburners were pretty well designed, but with a higher amount of oxygen, combustion would be more efficient and powerful, and with more pressure, even better. It took the load off the compressor which would have gotten way too hot (and everything downstream of it), and piped it into the afterburner which had different temp limits (way higher).
It was kind of a supercharged ramjet at this point, however it should be noted the engine was spinning throughout the whole cycle.