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The SR-71's predecessor used cesium-laced fuel to create radar-absorbing exhaust

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Re: The SR-71's predecessor used cesium-laced fuel to create radar-absorbing exhaust

#121

Post by jacobush »

jabl wrote: post #76
DuskStar wrote: post #41

Earlier quoted context omitted.

> Same line of thinking that results in depleted uranium tank shells. Yeah, since neither was particularly toxic, and both offered significant performance gains over the alternatives. (Uranium is extremely dense, self-sharpens on impact instead of mushrooming, and catches fire after penetration giving you an incendiary payload for free. Supposedly, nothing else comes close for tank rounds)

Several western countries use tungsten instead of DU. Apparently largely due to the political issues anything uranium brings.

If you call “toxic” and non biodegradable “political”, I agree with you. I think you will find that countries that expect the fighting to be largely in their backyard selected Tungsten and the countries that fight “overseas” selected Uranium.

Re: The SR-71's predecessor used cesium-laced fuel to create radar-absorbing exhaust

#122

Post by Aloha »

_jal wrote: post #106
faizshah wrote: post #50

Earlier quoted context omitted.

Some cool ones here: https://www.computerhistory.org/collections/fairchild/ Would be cool to see some old notebooks from Bell Labs tho like Ritchie or Thompson. I just found some old AT&T training manuals on Perl, TCP/IP, Bash, C and Unix internals, they are really cool.

Along the same lines, my bedside-book for the last few months has been Engineering and Operations in the Bell System[1]. It is... from another time. Both the quality of the engineering and the quality of the documentation simply don't happen anymore outside of very narrow niches. And then you look at the Death Star now, and their core competency is lobbying. Priorities certainly have changed. [1] https://www.worldcat…

I have the full set of books in this series, took me a couple months to track down.

There are no organizations left in the world like pre divesture AT&T - While I think divestiture was a net gain, it's clear that some things were not positive, and some stuff was irrevocably lost.

Re: The SR-71's predecessor used cesium-laced fuel to create radar-absorbing exhaust

#123

Post by myth_drannon »

We need to give a proper credit to the Soviet physicist Petr Ufimtsev (https://en.wikipedia.org/wiki/Petr_Ufimtsev) who's published papers in 60's on reflection of electromagnetic waves were read by Lockheed Martin engineers and that started the stealth program.

Re: The SR-71's predecessor used cesium-laced fuel to create radar-absorbing exhaust

#124

Post by showerst »

snowwrestler wrote: post #113
Daniel_sk wrote: post #80

Earlier quoted context omitted.

There is some stealth helicopter model that is secret and was used in the operation to kill Osama, it may be a heavily modified UH-60.

My recollection is that the contemporary reporting was pretty specific about what it was: an existing chopper with stealth tech grafted on. Something about that (the weight or shape) reduced lift and led to a crash landing during the mission. Some Google around NYTimes would probably turn up the details.

The story I heard at the time was that it was a combination of the stealth helicopters having lousy low-hover performance, and that during training they'd mocked a nearby solid wall up with a chain-link fence, which led to picking a poor landing zone.

Re: The SR-71's predecessor used cesium-laced fuel to create radar-absorbing exhaust

#125

Post by jpmattia »

I would love to know the thinking behind this method.

Off the top of my head: They are adding Cesium ("screw the environment, I have to escape my pursuer") to the engine in order to leave a plasmonic plume. The plasma, which occurs because the electrons in Cesium are stripped off in the heat of the engine, absorbs microwaves (ie, radar) because of the expected cyclotron physics of a free-electron gas.

However as an electronic countermeasure, I do not see the point. The plasmonic plume will absorb the microwaves where the rest of the plane will continue to reflect it. To my thinking, the is exactly what you do not want to do: You've reduced the microwave signal where the plane is not present, and done nothing to the signal where the plane is present. So you've improved the signal-to-noise for the enemy, which are providing guidance for anti-aircraft missiles.

Considering how many years this program went on for, my thinking must be wrong. Maybe anti-aircraft missiles of the era did not intercept from oblique angles (which takes serious computation and sensors) but could only hit from behind (where the plume would attenuate a signal)?

Re: The SR-71's predecessor used cesium-laced fuel to create radar-absorbing exhaust

#126

Post by dev_dull »

myth_drannon wrote: post #123

We need to give a proper credit to the Soviet physicist Petr Ufimtsev ( https://en.wikipedia.org/wiki/Petr_Ufimtsev ) who's published papers in 60's on reflection of electromagnetic waves were read by Lockheed Martin engineers and that started the stealth program.

> He gained permission to publish his research results internationally because they were considered to be of no significant military or economic value.

A decision I'm sure the Soviet Union would quickly come to regret.

Re: The SR-71's predecessor used cesium-laced fuel to create radar-absorbing exhaust

#127

Post by jacquesm »

phreeza wrote: post #65
aidenn0 wrote: post #15

Earlier quoted context omitted.

Yeah, the YF-23 wins a lot of cool points on looks alone[1], and it was faster and stealthier than the F-22. Taking the -22 was probably the right choice given that it was lower risk and absurdly better than anything it's likely to encounter in its operational life. 1: https://en.wikipedia.org/wiki/Northrop_YF-23#/media/File:YF-...

Oh man, growing up I had a book of aeroplanes, with diagrams and stats for hundreds of planes that I would obsess over. But the editors did a very cruel thing which was putting a photo of the YF-23 on the cover, but the plane was not in the book. Drove me nuts!

That may have been the first recorded instance of clickbait.

Re: The SR-71's predecessor used cesium-laced fuel to create radar-absorbing exhaust

#128

Post by blackflame7000 »

willvarfar wrote: post #74
avar wrote: post #62

Earlier quoted context omitted.

Turkey already bought F-35s[1], but are being told both that they can't buy anymore, and the servicing of the engines will be moved out of Turkey by 2020 if they insist on buying the S-400 from Russia[2][3]. Also, even if they didn't sell the F-35 to Turkey but still serviced the engines there that would make logical sense. The reason the US is paranoid about the S-400 is because they think radar data about the F-35…

From my reading, I don't think any of the F35s had been delivered, but some Turkish pilots had started training in the US in '18. That is now stopped. Over 900 parts in the F35 were made by Turkish companies, and they have to now be re-sourced. Now, I don't think the F35 operators want F35 engines sitting around in a country now receiving Russian military advisers. The idea that the engine isn't classified is crazy.

Russia has similar engines at their disposal as in the F35. The F22 engines however are extremely classified because of their ability to supercruise without afterburners.

The parts we keep secret are the stealth coatings which we do domestically and the sensor fusion which is mostly software based

Re: The SR-71's predecessor used cesium-laced fuel to create radar-absorbing exhaust

#129

Post by blackflame7000 »

willvarfar wrote: post #42
blackflame7000 wrote: post #25

Earlier quoted context omitted.

You can definitely see the B2 exhaust design in the Y23. It seems the Northrop gets the bombers and Lockheed gets the fighters. Makes sense logistically.

Nothing about modern fighter procurement makes any sense logistically! It seems the F22 was basically picked on the promise to make as many components in as many separate states as possible, in order to ensure every politician on the hill brought into it. And the idea of servicing different parts of the F35 in different buying countries is another logistical masterstroke, not! Oh my god, servicing F35 engines in Turk…

The thrust vectoring on the F22 makes it maneuver unlike any other aircraft including the F23 which lacked it.

Re: The SR-71's predecessor used cesium-laced fuel to create radar-absorbing exhaust

#130

Post by dkersten »

TheSpiceIsLife wrote: post #94
dkersten wrote: post #91

Earlier quoted context omitted.

As Neil Degrasse Tyson once said, even pilots aren't astronomers or astrophysicists and often don't know what they're seeing when they look at the sky.

I don't follow this line of reasoning. Correct me if I'm wrong, but isn't astronomy the scientific study of celestial objects; and astrophysics is the branch of astronomy concerned with the physical nature of those celestial objects. Why would either of those be the right consultants for UFOs, which are decidedly not celestial objects.

Because they are used to looking at the sky and looking at weird, odd or abnormal phenomena in the sky. They are therefore better equipped to know whether something strange in the sky is just one of the many strange natural phenomena or if its something that might be of alien origin.
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