The Russian physics paper was very theoretical and derived the equations needed to show that this technology was possible. The equations could not, and probably still can not, be directly solved. However, this paper was translated by the US Air Force as were many such technical publications and circulated through channels to aircraft manufacturers, and others. It was an engineer at Lockheed who realized that you could implement this technology without solving the equations if you were willing to devote huge amounts of computer resources to doing numerical solutions, which, are great for engineers, but frowned upon by theorists. We had the computer power to do this and the USSR did not. Even then the F117, sometimes called the wobbly goblin, had to sacrifice much in terms of aerodynamics and flight characteristics to implement the first true stealth aircraft.