The iconic SR-71 Blackbird set a speed record for crewed, jet-powered aircraft when it hit Mach 3.3 50 years ago. As NASA takes new interest in these planes, possibly as a testbed, we examine what it could take to get Blackbird close to Mach 4.
twz.com
Could NASA's SR-71 Blackbird Be Modified To Reach Mach 4?
The SR-71's airframe is capable of going beyond its known top speed and NASA may have good reason to push its limits via new engines.