I’d recommend reading Skunk Works by Ben R. Rich for more on the engineering of the Blackbird and other special aviation projects.
I knew the Blackbird was fast, but didn’t quite realize how fast until reading this book. The SR-72 would cruise at Mach 3, or three times the speed of sound. It would do this at 80,000 feet, over twice the traditional cruising altitude of a 747. Even at this height, where the temperature is -60°F, friction would cause the fuselage to heat to 600°F. This would melt traditional aircraft, so the plane was built with titanium (ironically supplied by the Soviet Union). The Blackbird used to overfly North Korea five days a week in just ten minutes.
I knew the Blackbird was fast, but didn’t quite realize how fast until reading this book. The SR-72 would cruise at Mach 3, or three times the speed of sound. It would do this at 80,000 feet, over twice the traditional cruising altitude of a 747. Even at this height, where the temperature is -60°F, friction would cause the fuselage to heat to 600°F. This would melt traditional aircraft, so the plane was built with titanium (ironically supplied by the Soviet Union). The Blackbird used to overfly North Korea five days a week in just ten minutes.