Consider that not much more than a decade before the SR-71 project started the state of the art in plane design was canvas over a wooden frame with a V12 engine

Consider that not much more than a decade before the SR-71 project started the state of the art in plane design was canvas over a wooden frame with a V12 engine that went at 300mph. How much technology did they have to invent from first principles to build a plane which flew at Mach 3 at the edge of space? Using slide rules and chalk boards?