No Blackbird was ever shot down. 12 crashed in non-combat situations though.
During its career, the SR-71 Blackbird gathered intelligence in some of the world’s most hostile environments. The SR-71 was conceived to operate at extreme velocities, altitudes and temperatures: actually it was the first aircraft constructed with titanium, as the friction caused by air molecules passing over its surface at Mach 2.6 would melt a conventional aluminum frame.
Its engineering was so cutting edge that even the tools to build the SR-71 needed to be designed from scratch.
These are just some of the many, interesting facts about the legendary Blackbird.
1. The cockpit glass was made of 1.25-inch thick solid quartz. Yeah.
2. This design meant that despite the aircraft flying at Mach 3+, it was one of the quietest aircraft on earth on the inside.
3. 21st century engineers researched with super advanced modern day technology to find how the Blackbird’s design could be improved. They concluded that there was absolutely no aerodynamic room for improvement: it’s perfect.
4. No Blackbird was ever shot down. 12 crashed in non-combat situations though.
5. The fuel was absurdly weird, as a lot of other answers have covered. In fact, it required a kick start by a highly explosive substance. The aircraft only carried enough of this chemical for a couple of engine starts, so if the engines had a multiple outage, they could not be restarted like in a normal aircraft.
6. The ram-jet design of those beautiful engines meant that the faster it went, the better they worked. One pilot reported that he hit Mach 3 (which is the maximum service speed) and the engines were not only still going fine, they were actually continuing to accelerate.
7. The M-21 was an aircraft based off the CIA Mach 3 A-12 reconnaissance aircraft (the SR-71 predecessor), but with a twist: this bad boy launched super high-speed drones. The drone, named the D-21, was essentially another J58 engine with some wings on the side. Sadly, an M-21 crashed after a drone launch. The D-21 program was thereafter launched by B-52s.
8. The wing spars in all of these aircraft had to be destroyed before being transported to the various museums they went to. This means that no SR-71 can ever fly again.
9. Many of these museums had to put big trays under the aircraft to catch all the fuel that dripped out of the fuel tanks (which are designed to leak btw). Apparently they take around 8–12 years to fully dry out, and they may continue to leak until that point.
So yeah, this is a pretty cool aircraft.
Photo credit : U.S. Air Force