Hard to believe the Soviets were using vacuum tubes instead of transistors <i>In hindsight, the MiG 25, which the West had been so worried about, turned out to be a ‘paper tiger’. Its massive radar was years behind US models because instead of transistors it used antiquated vacuum tubes (a technology that did, however, make it impervious to electromagnetic pulses from nuclear blasts). The huge engines required so much fuel that the MiG was surprisingly short-ranged. It could take-off quickly, and fly in a straight line very fast to fire missiles or take pictures.</i>