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SR-71 Blackbird was so fast it outran every missile and fighter jet encountered over enemy territory. In fact, neither enemy fighters nor enemy surface to air missiles were ever able to shoot down or to damage a SR-71. But the aircraft was never shot down also because it was hardly detected by enemy radars, being the first aircraft featuring stealth technology. Indeed, for the first time a special paint was used for Blackbird’s wings, tail and fuselage: since it contained iron ferrite, this paint absorbed radar energy instead of returning it to the sender.
If the only thing that matters was shaping, the SR-71 airframe could never be considered stealth. With an RCS of a small light aircraft, when the SR-71 was found on radar it was too late for a SAM computer to estimate its direction for a successful kill.
So, at that time, the SR-71 stealthiness was effective only because the Russians/Soviets didn’t have the proper technology to deal with him. Today, with the available technology, it would as detectable as an F-16!
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As I said before, stealthiness is about low detectability. At the time of SR-71, the Russians didn’t have the proper technology to detect the plane within time enough to deploy the countermeasures.
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