Back in the early 80s, I was walking outside from a computer store to my car when an SR-71 swept overhead, turning and low just after taking off at the nearby air station, with a kind of chattering shriek, and it was visibly LEAKING fuel (I later learned some parts of the plane aren't fully tight until they heat up in supersonic flight, which sounds impossible, but . . .). I can see how these things stick so strongly in the minds of those who work with them. Even today, they seem like impossible SciFi.
I later learned some parts of the plane aren't fully tight until they heat up in supersonic flight, which sounds impossible
Yes!
The SR-71 Blackbird expanded by approximately 2 to 4 inches in length due to intense heat during Mach 3+ flight. The titanium skin reached temperatures of 600–900°F, causing the aircraft's structure to grow and seal gaps that existed on the ground, where it was designed to leak fuel. 👀
It's mind blowing when you think about how the SR-71 was built back in the late 50s - no computers, only slide rules. It was built using titanium bought from USSR by a CIA front company.
One of the coolest things about it - the jet intake cones move in and out, to focus the super sonic shockwave into the intake of the engines. The shockwave is compressed air, and that makes it go that much faster. Kelly Johnson and his engineers at Lockheed's "Skunk Works" were total geniuses back in the day.
When I was about 18 I knew a guy who flew on KC-135's as a navigator. He was on the first refueling mission of the SR-71. Said it was scarey. The KC-135 had to fire wall its engines to get up enough speed to fly as fast as it could. Then the SR-71 had to pull back on its engines and was about to fall out of the sky. Two different types of planes trying to accomplish a common goal. My friend said it was a very sketchy moment because he though his plane might fall apart from all of the stresses on the frame.
The Blackbird is not fueled till the last minute before take off. I can’t remember now but when a wrench told me the leakage rate on the ground, I was shocked at the amount. These days if one took off at a Civi airport, they would have news on scene with hazmat and a weeklong breaking new news on the hazmat cleanup….
They also needed refueled after takeoff to replace the lost fuel. Here's a Google AI blurb on that:
The SR-71 typically required one aerial refueling immediately after takeoff (roughly 7–15 minutes into the flight) to fill its tanks for a mission, which was necessary to support the immense fuel consumption required to accelerate to Mach 3+ and reach altitudes over 80,000 feet. This initial, crucial refuel topped off the fuel lost from ground leakage and the high burn rate during ascent.
Back in the early 80s, I was walking outside from a computer store to my car when an SR-71 swept overhead, turning and low just after taking off at the nearby air station, with a kind of chattering shriek, and it was visibly LEAKING fuel (I later learned some parts of the plane aren't fully tight until they heat up in supersonic flight, which sounds impossible, but . . .). I can see how these things stick so strongly in the minds of those who work with them. Even today, they seem like impossible SciFi.
Yes!
Holy moley! Never heard such a thing before!
That is an interesting design. Thanks for the context there.
It's mind blowing when you think about how the SR-71 was built back in the late 50s - no computers, only slide rules. It was built using titanium bought from USSR by a CIA front company.
One of the coolest things about it - the jet intake cones move in and out, to focus the super sonic shockwave into the intake of the engines. The shockwave is compressed air, and that makes it go that much faster. Kelly Johnson and his engineers at Lockheed's "Skunk Works" were total geniuses back in the day.
That is amazing, I had never heard about that.
When I was about 18 I knew a guy who flew on KC-135's as a navigator. He was on the first refueling mission of the SR-71. Said it was scarey. The KC-135 had to fire wall its engines to get up enough speed to fly as fast as it could. Then the SR-71 had to pull back on its engines and was about to fall out of the sky. Two different types of planes trying to accomplish a common goal. My friend said it was a very sketchy moment because he though his plane might fall apart from all of the stresses on the frame.
Wow.
I've seen one on the ground before take-off. Gas was pooling everywhere on the ground.
The Blackbird is not fueled till the last minute before take off. I can’t remember now but when a wrench told me the leakage rate on the ground, I was shocked at the amount. These days if one took off at a Civi airport, they would have news on scene with hazmat and a weeklong breaking new news on the hazmat cleanup….
They also needed refueled after takeoff to replace the lost fuel. Here's a Google AI blurb on that:
I heard the SR-71 was designed to leak hydraulic fluid while on the tarmac. This is the first time I've heard about it leaking fuel.