Although it took several hours to complete the pre-flight preparations, once on the runway and both engines started, everything became straightforward.
No matter what, the "Dark Night Phoenix" was released a few years later than the SR-71A and adopted some new technologies that emerged after the SR-71A entered service. Moreover, the Empire's aviation technology is much more advanced than the Newland Republic, hence the overall performance of the "Dark Night Phoenix" significantly exceeds that of the SR-71A.
The most representative aspect is actually the engine.
The "Dark Night Phoenix" uses the PC-220, essentially similar to the SR-71A's J-58-1, both being first-generation variable cycle engines, optimized for high-altitude, high-speed flight. Besides achieving an impressive maximum afterburner thrust of 220 kN, the main difference, nearly as crucial as the engine, and perhaps more important, determining the fastest flight speed is the fuel load and delivery system.
