So That Happened: How a Russian Idea became an American technique

As World War II cooled in the 1940’s, the US built nuclear-armed planes to send deep into Russia. The Soviet Union responded in the 50’s by building Surface-to-Air Missiles that could fly up and intercept the planes faster than human-piloted planes. And so began an arms race. The US built planes that could fly higher. The USSR built missiles that could fly higher. In the 60’s, the US built planes that could fly faster. The USSR built missiles that could, well, you get the idea. And by the 70’s, there wasn’t any higher or faster left to fly. So, what was the US’s next move? The answer came from the USSR itself, in one of the more ironic (not just Alanis Morrisettical ironic) twists of the Cold War.

The reigning philosophy for military plane designers had been “See but Don’t Touch.” Planes that flew higher, flew faster, turned tighter, even planes that could send out distracting radar signals. But then, an idea. Radar operators had always known that different planes looked slightly different on radar. [Refresher: radar works by sending radio waves out, and seeing where they bounce back from. The more radio waves that bounce back, the bigger the dot on the screen looks] And that makes sense: bigger planes should look bigger. But... it wasn’t just size, or just amount of metal (the part of the plane that reflects radio). Some big planes looked small, and some small planes looked big. If they could figure out what it was that made a plane look big or small on radar, they could design a plane that looked invisible.

The solution was “Method of Edge Wave in the Physical Theory of Diffraction”, an obscure technical paper from 10 years earlier and half a world away. Published by Petr Ufimtsev, chief scientist of the Moscow Institute of Radio Engineering, it described how to calculate a shape’s “Radar Cross Section” (i.e., how big it looks on radar).

So given this gem of insight into our physical world, what did the Soviet higher-upniks do? Did they build a whole new generation of invisible planes and fly them from Havana to Washington? No. But, they had a different strategy, so the Dr. Strangelovean fleets of bombers was never really their jam. OK. So, did they classify it as a state secret and stack it up in the Russian equivalent of that warehouse with the Lost Ark? No. Because Ufimtsev’s work was only practical to determine the RCS of simple shapes. And you can’t fly a cube.

Well, maybe, you say, it’s because the USSR just really believed in openness. And, well, no. Not really. They classified huge amounts of aeronautics research. They kept secret all the data that came out of their testing programs. But anyone in the US could replicate testing data (testing data is when you carve a shape out of soap or balsa wood, throw it in a wind tunnel, and write down the numbers). No one in the US was figuring out the math of “Method of Edge Wave in Boring Theory Yadda Yadda.” The US’s coup de grace Cold War plane design is due to a Soviet Censor stamping “looks fine” on a seminal theoretical advance.

Tomorrow, we’ll cover how engineers in the US took this nugget of egghead-ness and ran with it. Ran with it to the tune of 4 awesome planes and 200 billion dollars.