Stealth bomber

Now this is funny ... or sad? In 1990, the U.S. AirForce unveiled its newest long range bomber: The B-2 "Stealth" bomber had cost billions to develop. It was characterized by its all-wing design: The analysis included a ritual for finding the volume distribution that maximized the range. The ritual involved taking a derivative and setting it equal to zero. Conclusion? The volume should be "almost all in the wing". Hence the B-2. Alas, the engineers who recommended the all-wing design neglected to test the second derivative ... to see if'n they found a maximum or a minimum. It turned out (as discovered subsequently), that the all-wing design MINIMIZED the range of the aircraft. Indeed, the flying wing was, aerodynamically, the worst possible configuration. Now, if'n I only had that story at my finger tips when I taught introductory calculus!