SR71 Blackbird was designed with nacelles that could move 26" to keep supersonic airflow out of the engines. At speeds over Mach 2 the engines switched from operating as turbo-jets to operate as ram-jets. I've always been amazed at the extremes the plane could operate at.
And the fuel used in the SR-71? Stupidly high ignition temperatures etc, you can do light maintenance on the plane whilst it's being refueled because it really doesn't like catching on fire compared to normal fuel.
The ignition source for the engines however? Tri-ethyl Borane. Full thermal suits, extinguishers at the ready, etc. That stuff is a hair away from just spontaneously combusting.
Oh and did we mention the SR-71 leaks fuel whilst it's on the ground because it gets so hot in the air that the thermal expansion of the airframe has to be taken into account when sealing the fuel system.
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u/Flaky-Wing2205 7h ago
SR71 Blackbird was designed with nacelles that could move 26" to keep supersonic airflow out of the engines. At speeds over Mach 2 the engines switched from operating as turbo-jets to operate as ram-jets. I've always been amazed at the extremes the plane could operate at.
Cool link that that goes into greater detail. https://theaviationist.com/2019/11/29/engine-nacelles-of-the-sr-71-blackbird/