Bill Sweetman has a great story of a recent personal account from a former USAF guy that was part of the Cold War program flying Soviet-made (or similar) MiG aircraft in Nevada.
Those days were secret, dangerous yet eye-opening.
That proved to be a very important test. "In 1987 we had the AIM-9P, which was designed to reject flares, and when we used US flares against it would ignore them and go straight for the target. We had the Soviet flares – they were dirty, and none of them looked the same – and the AIM-9P said 'I love that flare'.
"Why’d that happen? We had designed it to reject American flares. The Soviet flares had different burn time, intensity and separation. The same way, every time we tried to build a SAM simulator, when we got the real thing it wasn’t the same.
"I use the AIM-9P because it is out of the system and I can talk about it. The same thing happened to a lot of things that are still in the system and that I can’t talk about."