Tricky Woo,
<font face="Verdana, Arial, Helvetica" size="2">I seem to remember that the cone-shaped nozzle on the SR71 is adjustable, fore and aft, to allow the position of the shockwave to be matched against the airspeed. True?</font>
Yes, true.
<font face="Verdana, Arial, Helvetica" size="2">Seeing as the SR71 was designed to accelerate to, and cruise at, Mach 3, why has Boeing shoved similar intakes onto their 'almost sonic' design? Something pretty that the artist thought up? Or an important part of the design?</font>
To quote the
Aviation Week & Space Technology interview with Michael B. Bair, Boeing Commercial Airplanes vice president for business strategy and development, he said
<font face="Verdana, Arial, Helvetica" size="2"> To keep noise down, the fan and core exhaust will be mixed before exiting, and the inlet has a long duct to suppress fan noise. "The fan face can't be seen," Bair said, making the sonic cruiser appear as if it has taken stealth lessons from military aircraft (AW&STMar. 19, p. 92). Indeed, Boeing claims the design draws from military aircraft such as the F-22.</font>
From an aerodynamics point of view if the airflow has been accelerated in some way via duct or over the wing it may be supersonic flow and require some form of shock to be created to limit the air into the engine.
Seems like a marketing think to me, little efficiency gained for a whole lot of work.
