When the SR-71 was was under development they had a weight problem. Even using Titanium everywhere they could, even leaving out every last possible thing that contributed nothing but added weight, they were pushing the weight limit to the very edge. Kelly Johnson, lead engineer of Project Oxcart, got so desperate he offered his engineers, mechanics, and assembly line folks, up to a hundred dollars for every pound they could cut from the design. In the midst of this, Johnson's right-hand man, Ben Rich, made a suggestion: paint it black. That might not sound like much, but on an aircraft that size, with the type of paint they used, it was going to add 1,100 pounds of weight. When Johnson was tearing his hair out trying to save pounds, his top guy was talking about adding 1,100 pounds in one fell swoop! Just to paint it black. Why?