Why The Mach 3 SR-71 Blackbird Was Never Shot Down

19FortyFive ^ | 9/13/2022 | Brent M. Eastwood

[GingisK]

It has never been fire-walled.

[Paal Gulli]

Jeez, what an worthless website.

"Why The Mach 3 SR-71 Blackbird Was Never Shot Down"

No, it was a Mach 3+ aircraft. An important distinction because the MiG-25 was built specifically to shoot down SR-71s. And they could do Mach 3.2 ... at lease once ... sometimes.

It's operational speed was quite a bit lower but in 1973 the Israelis clocked an overflight from an Egyptian MiG-25 at Mach 3.2. Not Soviet puffery, American-made, Israeli-operated radar. After which the pilot returned to base so they could change his engines. And he could change his underwear.

But in 1974 an SR-71 cruised across the Atlantic at Mach 3.2. Not Mach 3, Mach 3.2. And they didn't even have the gas pedal all the way to the floor.

[Paal Gulli]

"If I recall, much of the titanium came from the Soviet Union."

Not much, all. The CIA set up a shell corporation to buy it from the USSR.

[Captain Peter Blood]

They built the U2 in 18 months and with a slide rule.

[Paal Gulli]

"Why did they retire the SR-71 yet they are still flying the U-2?"

The three biggest reasons are:

1. Spy satellites now collect most of the same intel as an SR-71 could without risk of sparking an international incident.

2. The US no longer makes a habit of overflying denied territory, which was the SR-71's primary reason for existing.

3. Time has not stood still. There now are AAA missiles with the range ad the speed to turn an SR-71 at 100,000 feet and making Mach 3.5 into a cloud of titanium dust.

U2s are cheaper, more flexible, and aren't so picky about the airfield they're operated out of, or how it's equipped.

SR-71s needed a really long runway and a lot pf pre-flight prep (for instance, the oil has to be pre-heated). So there were no "spur of the moment" missions. It took a specialized starter (ground power unit) that ran on twin Buick Wildcat V-8s to crank it up, so there was a lot of bespoke equipment involved.

[nascarnation]

OK this had to have been awesome...

On engine launch there was one AG-330 Buick for each SR engine. For the first time observer of an SR-71 launch, the engine starts in themselves were almost indescribable. For one thing there was no mufflers on the Buick engines. As the Buick RPM was advanced, Flames almost three feet long erupted from the side of the start cart. It truly sounded like the beginning of the Indianapolis 500. Combine that sound with the steady increase of SR-71 RPM to engine TEB ignition at 3,200 RPM and then idle aircraft engine speed as the Blackbird comes to life.

[Paal Gulli]

...The J-58 engines are mind bending. To think they were designed in the 50’s........"

Sort of.

An "off-the-shelf" J58 only makes 17.6% of the thrust as the ones used in the SR-71. The other 82.4% was Skunkworks hot-rodding.

Along with the other magic, the faster the plane flew, the more air that was bypassed from the intake directly to the afterburners. Which made the afterburners progressively more efficient. So once it went supersonic, it burned less fuel the faster it went. Its lowest fuel burn rate was at Mach 3.2.

[Paal Gulli]

"The MIG31s were able to get lockons on the SR71s..."

Never happened.

"...The USAF stopped the USSR overflights as a result...."

Nor did this.

[Paal Gulli]

"...It leaked like a sieve on the ground but the friction from the atmosphere expanded the fuselage parts and they all tightened up niceley. ..."

Normal airplanes have a "water-tight" fuel bladder inside the wing. The SR-71 leaked fuel on the ground because it couldn't have a fuel bladder. It couldn't have one because the JP-7 fuel would dissolve all known bladder materials.

[Rummyfan]

Thanks. I knew guys who worked on Global Hawk and they were still battling the USAF to get more missions for the Global Hawk as opposed to the U-2. And the U-2 is very physically hard on pilots.

[Seruzawa]

Er. Yes it did.

[doorgunner69]

My understanding was the Mig 25 was intended to counter the Mach 3 B-70. A nuclear bomber they could not stop vs a spy plane. Priorities.

[SunkenCiv]

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[SunkenCiv]

Yeah, that’s the punchline — the CIA set up a front, I think in India, got the ore mined and shipped out of Central Asia (then part of the now-mostly-defunct USSR), and brought to the US to be turned into spy planes to overfly the USSR (among other places). Gotta believe they were allowed to find that out. :^)