22. The fuel tanks held fuel about as well as a colander holds water
Thanks to the supremely high operating temperatures, and due to the way materials expand with heat, the body panels were engineered to fit very loosely when cold. On the ground, they leaked so badly that crews would fill the plane immediately before takeoff, and while the plane warmed up, it had to meet with a refueling rig after only seven minutes in the air.
23. SR-71s spent a lot of time behind refueling planes
Those engines burned upwards of 44,000 pounds of fuel each hour, making refueling every 90 minutes a necessity. Making that number even more impressive is that, due to what’s known as the ramjet effect (air and fuel compressing at supersonic speeds), Blackbirds became more fuel efficient at speeds above Mach 2.0, and typically covered about 2,500 miles in that 90 minutes.