Wow! SR-71 Pilot Describes A Mission Over Libya

Major Brian Shul describes his love affair with the SR-71, including a mission over Libya. Worth reading in full. The picture over there of the SR-71 shows the shock diamonds in the exhaust from the SR-71's engines--I'm counting ten of them. My recollection from my junior high readings is that the number of shock diamonds that you can see in a rocket exhaust roughly indicates how fast the exhaust is moving--with each diamond representing Mach 1 (the velocity of sound). If so, the exhaust of these engines was moving at about 6600 miles per hour--which wouldn't surprise me, considering that the plane regularly set speed records above 2100 miles per hour.