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Just read a wild fact about the SR-71 Blackbird's fuel system
I was looking through an old maintenance manual from the Air Force museum in Dayton and saw that the SR-71 would leak up to 600 gallons of fuel on the ground before a flight. The airframe was built with loose panel gaps that only sealed from the heat of flying at Mach 3. I had no idea they literally designed it to leak on purpose. Has anyone here ever worked on a bird with a design quirk that crazy?
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the_leo2mo ago
I read that the Blackbird's fuel was basically a heat sink for the cockpit and electronics too. The JP-7 was so stable they'd use it to cool the avionics before burning it. They even had a separate tank of a more volatile fuel just to start the engines. The whole system was built around managing that insane heat.
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willowg881mo ago
The SR-71 fuel leak thing is one of those facts that sounds fake but is completely real. I remember reading an interview with a former Blackbird pilot who said they'd taxi out with fuel literally raining off the wings and the ground crew would just be standing there in it. The JP-7 fuel was so thick and had such a high flash point that it wouldn't even catch fire from a lit match, so the leaks were more of a mess than a danger. And yeah, the whole cooling system thing is wild too - they'd run the fuel through the avionics before burning it to keep everything from melting. The plane was basically a controlled leak with a jet engine attached.
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brianm662mo ago
My buddy was a crew chief on F-4 Phantoms back in the day. He told me they had these big rubber fuel bladders in the wings that would sag and crease over time. They’d have to send guys in through the access panels to literally crawl inside the wing and smooth out the wrinkles by hand so the fuel gauges would read right. Always thought that was a wild way to fix a plane.
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