Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

thedrive.com

Post reply on HN
Print view View original

101–110 of 160 posts

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

#101

Post by sokoloff »

regularfry wrote: post #54
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)

Uranium is... not nice stuff. I wouldn't classify it as "not particularly toxic". https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2819790/

This is in the context of a substance we’re trying to use to destroy enemy tanks and kill/injure combatants, not make s’mores out of.

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

#102

Post by dsfyu404ed »

galangalalgol wrote: post #21
nunb wrote: post #17

Earlier quoted context omitted.

YF-23 actually looked futuristic, the F-22 looks like a mild modernization of the F-15/18

The kingfish looked like something more modern than an f-117. The f-16xl that lost to the f-15e looked like a modern European design. The boeing jsf was... Ugly, but the grumman one was cool looking. Its kind of a trend, the losers are so much cooler.

I'm surprised the Israelis never bought the XL since they basically use the F16 as a bomber.

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

#104

Post by ohiovr »

nullc wrote: post #44

My experience with cesium is that everyone thinks its radioactive. It isn't-- like many common elements there is a radioactive isotope, but that is not what would have been used here. I speculate this worked by the highly reactive cesium ionizing the air. Similar things have been done with doping rocket fuels with metals to stimulate lightning strikes. Presumably most of the cesium would end up reacted very quickly,…

Caesium is the easiest metal to ionize. It also has a fairly low work function. So it is easy to turn the metal into a plasma.

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

#106

Post by _jal »

faizshah wrote: post #50
taneq wrote: post #31

Earlier quoted context omitted.

I would love to see some kind of web database of old engineering notebooks like this, surely there are enough now kicking around in boxes of "grandad's junk".

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.org/title/engineering-and-operations-in...

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

#107

Post by [deleted] »

nullc wrote: post #44

My experience with cesium is that everyone thinks its radioactive. It isn't-- like many common elements there is a radioactive isotope, but that is not what would have been used here. I speculate this worked by the highly reactive cesium ionizing the air. Similar things have been done with doping rocket fuels with metals to stimulate lightning strikes. Presumably most of the cesium would end up reacted very quickly,…

[deleted]

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

#108

Post by decoyworker »

coolspot wrote: post #13
syntaxing wrote: post #5

I know it's toxic but from a technical aspect, that is really cool. I remember reading that the Apache Helicopter (I think?) can redirect it's exhaust internally temporarily to become invisible to heat seekers. Some of these technologies are super fun to read about.

Most military helicopters having some ways of masking IR signature: https://www.sciencedirect.com/science/article/pii/S100093611...

https://en.wikipedia.org/wiki/Common_Infrared_Countermeasure...

>Infrared guidance systems in heat-seeking missiles are designed to track strong sources of infrared radiation

>Directional IRCM, or DIRCM, allows for a countermeasures laser to be targeted directly at an incoming IR threat.

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

#109

Post by ufmace »

acqq wrote: post #96
manigandham wrote: post #89

Earlier quoted context omitted.

Yes, it's rather cynical. And yet it's this very tension that keeps the peace. The world is now in the longest stretch of world-wide peacetime ever in history.

> The world is now in the longest stretch of world-wide peacetime ever in history. Peacetime where? There was constant war since WW II mostly directly or indirectly waged by the US.

Peacetime everywhere. The post-WWII wars are all tiny by comparison. The nuclear era is historically unprecedented in the total lack of direct warfare between major industrial powers.
Post reply on HN