Mach 3.5 Over Libya in an SR-71 Blackbird • Hacker News Board

Re: Mach 3.5 Over Libya in an SR-71 Blackbird

#61

Post by AdamN » Thu, Mar 30, 2023, 4:51 PM UTC

cm2187 wrote: post #56

geocrasher wrote: post #25

Indeed, Mach 3.5 is the declared top speed in this story, but higher speeds are implied. The Mach eases to 3.5 as we crest 80,000 feet... Screaming past Tripoli, our phenomenal speed continues to rise... I realize that I still have my left hand full-forward and we're continuing to rocket along in maximum afterburner... The TDI now shows us Mach numbers, not only new to our experience but flat out scary. He mentions u…

Temperature is the limiting factor for speed, I remember SR71 pilots on a panel saying the aircraft flew faster in winter than in the summer for that reason.

It's also cool that the whole thing was machined 'loose' so that it would expand as it heated up. Apparently the plane would leak fuel and oil when it was on the ground ...

Re: Mach 3.5 Over Libya in an SR-71 Blackbird

#62

Post by swasheck » Thu, Mar 30, 2023, 4:51 PM UTC

anonymousiam wrote: post #55

Some interesting trivia: The SR-71 began as the YF-12, and was originally supposed to be RS-71 (Reconnaissance/Surveillance), but somebody thought SR sounded better. The YF prefix on the original aircraft is often referred to as "Yankee Fire", a caveat that is still in use.

legend is that president johnson got it confused in a press conference and called it the sr-71 so instead of correcting him they just changed the name.

"skunk works" is a great read. i'm almost done with "area 51" by annie jacobsen and it's quite the interesting read as well, though it does get dry at times. https://openlibrary.org/works/OL15839422W/Area_51

Re: Mach 3.5 Over Libya in an SR-71 Blackbird

#63

Post by StrangeATractor » Thu, Mar 30, 2023, 4:52 PM UTC

philipkglass wrote: post #54

ben7799 wrote: post #45

Earlier quoted context omitted.

Which is really odd, as Titanium is not that rare. Are we sure that story about the Titanium coming from the USSR is accurate?

Titanium is very common in the Earth's crust. But turning titanium minerals into pure, ductile titanium metal is more energy intensive and complex than making most other metals: https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/... At the time, the USSR had already invested significant resources into making titanium for submarines. Buying titanium under false pretenses was easier than increasing the domesti…

Re: Mach 3.5 Over Libya in an SR-71 Blackbird

#64

Post by strictnein » Thu, Mar 30, 2023, 4:56 PM UTC

geocrasher wrote: post #25

Indeed, Mach 3.5 is the declared top speed in this story, but higher speeds are implied. The Mach eases to 3.5 as we crest 80,000 feet... Screaming past Tripoli, our phenomenal speed continues to rise... I realize that I still have my left hand full-forward and we're continuing to rocket along in maximum afterburner... The TDI now shows us Mach numbers, not only new to our experience but flat out scary. He mentions u…

Such a great book that is becoming harder to find a decent copy of these days.

There's a great sketch that Kelly Johnson did of the A12. This was in September of 1958(!) and he had a rough top speed of Mach 3.0, with a possibility of Mach 3.2. And it existed on nothing but a sheet of paper and in his mind. No computers with advanced software and super computers with petaflops of power.

https://www.thesr71blackbird.com/History/CIA/a-12-blackbird-...

Re: Mach 3.5 Over Libya in an SR-71 Blackbird

#65

Post by arcanemachiner » Thu, Mar 30, 2023, 5:00 PM UTC

igravious wrote: post #22

mardifoufs wrote: post #14

I love stories about America violating sovreign airspace, especially when they use such a cool plane. The entire world is truly their own backyard!

The days of America violating sovereign airspace are drawing to a close, thankfully. “The United States-initiated aerial bombing of targets inside the borders of the Libyan Arab Jamahiriyah which took place on April 15, 1986, was met with substantial and immediate criticism by the world community. The positive reaction from the U.S. congress and the American public was not shared by much of the world. Arab nations de…

I wouldn't hold my breath... The US launched an airstrike in an illegally-occupied (Syria) nation less than a week ago.

https://news.antiwar.com/2023/03/25/us-carries-out-airstrike...

Re: Mach 3.5 Over Libya in an SR-71 Blackbird

#66

Post by laverya » Thu, Mar 30, 2023, 5:09 PM UTC

anonymousiam wrote: post #55

Some interesting trivia: The SR-71 began as the YF-12, and was originally supposed to be RS-71 (Reconnaissance/Surveillance), but somebody thought SR sounded better. The YF prefix on the original aircraft is often referred to as "Yankee Fire", a caveat that is still in use.

Pretty sure that the CIA's A-12s came before the YF-12 interceptor prototype.

Re: Mach 3.5 Over Libya in an SR-71 Blackbird

#67

Post by davidu » Thu, Mar 30, 2023, 5:13 PM UTC

mardifoufs wrote: post #14

I love stories about America violating sovreign airspace, especially when they use such a cool plane. The entire world is truly their own backyard!

The world hates that the US is the world police, but then constantly demands the US be the world police.

Re: Mach 3.5 Over Libya in an SR-71 Blackbird

#68

Post by 93po » Thu, Mar 30, 2023, 5:17 PM UTC

saganus wrote: post #36

ilamont wrote: post #28

Ironically, the plane was dripping, much like the misshapen model had assembled in my youth. Fuel was seeping through the joints, raining down on the hangar floor. At Mach 3, the plane would expand several inches because of the severe temperature, which could heat the leading edge of the wing to 1,100 degrees. To prevent cracking, expansion joints had been built into the plane. Sealant resembling rubber glue covered…

In the "Skunk Works" book they explain that you could throw a lit cigarette directly into a puddle of fuel and it would not ignite, due to the very high temps needed.

Cigarettes also won't ignite regular car gas

Re: Mach 3.5 Over Libya in an SR-71 Blackbird

#69

Post by sbaiddn » Thu, Mar 30, 2023, 5:20 PM UTC

geocrasher wrote: post #25

Indeed, Mach 3.5 is the declared top speed in this story, but higher speeds are implied. The Mach eases to 3.5 as we crest 80,000 feet... Screaming past Tripoli, our phenomenal speed continues to rise... I realize that I still have my left hand full-forward and we're continuing to rocket along in maximum afterburner... The TDI now shows us Mach numbers, not only new to our experience but flat out scary. He mentions u…

Adrian Newley is aerodynamist and the current chief designer of Red Bull (current champions and top of the season). He has won more F1 champions than any other designer.

He draws his cars on paper.

Granted, I'm sure someone digitizes his designs and runs them through a CFD suite, if for no other reason that wind tunnel time rule limited.

Still.

Re: Mach 3.5 Over Libya in an SR-71 Blackbird

#70

Post by sbaiddn » Thu, Mar 30, 2023, 5:22 PM UTC

cm2187 wrote: post #56

geocrasher wrote: post #25

Indeed, Mach 3.5 is the declared top speed in this story, but higher speeds are implied. The Mach eases to 3.5 as we crest 80,000 feet... Screaming past Tripoli, our phenomenal speed continues to rise... I realize that I still have my left hand full-forward and we're continuing to rocket along in maximum afterburner... The TDI now shows us Mach numbers, not only new to our experience but flat out scary. He mentions u…

Temperature is the limiting factor for speed, I remember SR71 pilots on a panel saying the aircraft flew faster in winter than in the summer for that reason.

What does winter mean at 80 000 ft and Mach 3?

The jet stream is insanely fast at that altitude mixing the air, and at Mach 3 the surface weather changes in fractions of a minute.