Re: Which was the bigger engineering challenge ? Concorde. Or Apollo ?
Bad intakes? Close but not quite.
Top speed of the B1-A prototypes were about 2.1 to 2.3 Mach at high altitude. B1-B, though, added the requirement of low level penetration and reduced RCS, as the USAF realized high speed / high altitude was useless against contemporary air defense systems. Hence the abandonment of the XB-70 (3+ Mach) bomber and the 2+ Mach B-58 Hustler, which was removed from service all the way back in 1970.
Why is the B1-B slower than -1A? For RCS reduction, the B1-B ended up with fixed vice variable intake ramps instead of the variable ramps of -1A and a serpentine duct that prevents any direct line of sight to the fan face. Limits speed to something like 1.2 Mach... But then, it can go 0.92 Mach on the deck, which is damned impressive. Above 1.2Mach, supposedly the intake serpentine can incur damage.
Basically, a nice, hot 3+ Mach aircraft at altitude is a hell of a missile sponge. And you're not outrunning any missiles. Survival involves terrain masking and RCS reduction, not peak speed.
Biting the hand that feeds IT
