posted on Jul, 16 2012 @ 06:26 PM
reply to post by A-star
Nonsense. The SR-71 was not designed to sustain hypersonic speeds.
All Blackbird variants were designed to obtain maximum cruise performance around Mach 3.2 at altitudes from 74,000 to 85,000 feet. The external
configuration, engine air inlet system, powerplant, and fuel sequencing were optimized for performance at Mach 3.2 and the airplane attained true
airspeeds near 1,850 knots.
In 1965, a CIA pilot flew an A-12 to a maximum speed of Mach 3.29 (2,171 mph). According to the SR-71 pilot’s handbook (flight manual), Mach 3.17
was the maximum recommended cruise speed for normal operations. The pilot, however, could increase speed to Mach 3.3 as long as the engine compressor
inlet temperature did not exceed 427 degrees C. Speeds exceeding Mach 3.3 were occasionally recorded during test flights, but these operations put
excessive thermal stress on the airframe.
In July 1976, relatively cool outside air temperatures allowed an Air Force crew to set an official speed record in the SR-71A, accelerating to Mach
3.32 (2,193 miles per hour). This record stood even after the airplane’s official retirement flight in March 1990 set a 1,998-mile straight-course
speed record from Los Angeles to Washington, D.C., in just over 64 minutes at an average speed of 2,144 miles per hour.