Thanks Denny .. Cool Stuff ... today flight test folks are lucky to ever see a new program.

Here's the story on the XB-70



The aircraft was redundant by the time it flew. It's role was replaced by the MRV ICBM's and performance had already been leapfrogged by the A-12 / SR-71. None the less, a lot of the structures technology was later used in components of the aircraft we fly today.