Modern engines still can't match it: How Pratt & Whitney's J58 physically grew 6 inches inflight

The high sustained speeds of the SR-71 heated the engines to the point that the aircraft and engines dramatically expanded.
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Only 17% came from the engine: How the A-12 made Mach 3

At Mach 3.2, the A-12’s J58 turbojet core supplied only about 17% of total thrust; the carefully controlled inlet produced 54 ...