[Long Cut]

True Dat, AR. If a MiG-25 went up to its top speed of Mach 3, its engines had to be changed out, and its entire airframe inspected.

It was basically a capability which was to be used only in an extreme emergency, like an all-out war.

I've heard through the grapevine that F-15s also had a "dash" capability only to be used in war, which likewise would trash the engines if used too long.

[Robert A Cook PE]

Concur:

The Mig-25 was built to take on the B-71 (and other high-altitude, high-speed bombers: fast, relatively short range, fighting with VERY simple electronics and sensors (because they were cheaper, and would work in a EMF environment, and were available) and a heavy airframe to withstand high heat.

The Soviets goofed on a couple of things though: building the 25 meant we HAD to aim higher and our aircraft improved tremendously: at a higher price though.

They ran out of money for better quality aircraft spending it a a high-speed showboat. Performance wasn't as good as US aircraft at anything but straight lines at high altitude.

US supersonic bombers didn't really work well and were canceled (Hustler, FB-111, and B-71 and the proposed A-12 bomber version) and the low speed bombers became "more stealthy" when these were canceled. (B-1, B-2, F-117 in particular.)

So their hot-shot aircraft wasn't needed for what it was designed to do, and couldn't do anything else real well.