Dr. Pytr Ufimstef was the Russian physicist who derived the equations for minimizing radar return to the transmitter by an angled surface. He took his findings to the KGB who determined that such science had no military value whatsoever and allowed him to openly publish his findings. They came to the conclusion that any airframe based on his science could not fly. And they were right. What they did not have was the computer-based fly-by-wire technology that we had, which allows unstable airframes to reliably fly. And the rest is history.
Exactly right!!!