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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

#71

Post by nullc »

dschuetz wrote: post #61
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,…

Well, you are correct in just some cases. Caesium has only one stable isotope, so beside the actual Caesium and Caesium-133 everything else has ß-decay. Unless you are burning 100% refined Caesium, there is always a chance that you are also burning its radioactive isotopes.

All the isotopes of Cs other than 133 exist only in negligible amounts in nature. So sure, perhaps there would be a trace amount of something else-- but that is true of anything.

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

#72

Post by austinheap »

TeMPOraL wrote: post #57
dmix wrote: post #51

Earlier quoted context omitted.

> He is also deeply into monetizing Navy-UFO conspiracy. A lot of these otherwise sensible warfare blogs are getting heavily into this. I don't understand it. But clearly it attracts a big audience and they've always been a niche blog topic so I guess they like the attention.

Attention -> pageviews -> ad money. The fundamental value chain of most news reporting today.

Feels like a stretch that multiple military personnel went on record and conspired to make this up for the clicks on a blog? Far easier ways to drive traffic.

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

#73

Post by jabl »

jazzyjackson wrote: post #48
IcePenguin wrote: post #12

Earlier quoted context omitted.

Yep! It's called TEB (Triethylborane). More info here: https://en.wikipedia.org/wiki/Triethylborane JP-7 has a very high ignition temperature (it was actually used as a coolant/heat sink for the rest of the aircraft), so TEB combusting once it hit the air is used to light the engines. SR-71s only had a limited amount of TEB to use each flight. I believe it was 13 shots per engine. TEB was used each time the engines w…

I don’t know anything about afterburners, if it’s the same fuel as the usual engine, what about it needs to be lit with a lower temperature fuel? I always assumed afterburners just meant opening the throttle up but there must be more to it

> I always assumed afterburners just meant opening the throttle up but there must be more to it

No, as the name implies it's literally pouring in fuel after the turbine, in the exhaust. The exhaust is hot, yes, but cooler than the combustion chambers (which reside in between the turbine and compressor). So if you have some special fuel that's very hard to ignite then maybe you need some help to get the afterburning started.

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

#74

Post by willvarfar »

avar wrote: post #62
willvarfar wrote: post #42

Earlier quoted context omitted.

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…

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.

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

#75

Post by close04 »

mgarfias wrote: post #43
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-...

Funny, the way i remember it happening: both YF-22s were lost do to mishaps, the YF-23 was faster, stealthier, and just as maneuverable without the vectored thrust. The AF wanted the -23, but the chairman of the senate armed services committee was from Georgia, where Lockheed promised to build the -22. and the history got rewritten. Source: Dad was part of the YF-23 program at northrop and lost his gog when the proje…

> the way i remember it happening: both YF-22s were lost do to mishaps

Seems they're museums pieces now and look relatively unscathed. [0][1]

> The two YF-23 prototypes were museum exhibits as of 2010

[0] https://en.wikipedia.org/wiki/Northrop_YF-23#/media/File:YF-...

[1] https://en.wikipedia.org/wiki/Northrop_YF-23#/media/File:YF-...

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

#76

Post by jabl »

DuskStar wrote: post #41
treggle wrote: post #11

Of course, because nothing matters more than getting the advantage. Same line of thinking that results in depleted uranium tank shells.

> 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.

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

#77

Post by jabl »

tjohns wrote: post #64
saagarjha wrote: post #37

Earlier quoted context omitted.

More bad news: we still put it in avgas.

They're working on a replacement for 100LL avgas, thankfully. There's some flight safety concerns that have delayed it, but it's still a work in progress.

Last I heard the project has stalled. And with the current administration there's unlikely to be political pressure to get it rolling.

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

#78

Post by tempguy9999 »

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.

> I know it's toxic but from a technical aspect, that is really cool.

People who think like this make want to cry. Those who can see the consequences and choose to overlook them.

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

#79

Post by jabl »

treggle wrote: post #11

Of course, because nothing matters more than getting the advantage. Same line of thinking that results in depleted uranium tank shells.

Apparently back in the day they were seriously considering ClF5 as the next generation oxidizer for rocket propellants. Implying that the rocket exhaust would to a large extent consist of HF and HCl. Yikes!

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

#80

Post by Daniel_sk »

taneq wrote: post #35
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.

The Comanche vented its turbine exhaust into the wash from the tail rotor, iirc, to make it harder to spot. It also used a 5-blade rotor instead of the traditional 2-blade rotor in order to make it quieter. There's a bunch of cool things we could do to make helicopters more stealthy if we cared enough.

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.
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