Aviation Week has a great scoop today about what could be a major addition to the Air Force’s fleet: the successor to the legendary SR-71 Blackbird. Lockheed Martin’s new hypersonic reconnaissance and long-range strike aircraft, dubbed SR-72, would hit max speeds of Mach 6 with the help of a scramjet, Aviation Week said. That would be about twice as fast as its predecessor’s top speed. The original Blackbird, of course, is one of the most iconic aircraft in Air Force history. During its 24-year career, it was the world’s fastest and highest-flying operational aircraft. In 1976, a Blackbird set two…