DARPA Looking into Hypersonic Bombers

while(true) writes "As reported previously here on Slashdot, hypersonic jets from NASA has recently been in the news. Now DARPA is showing interest in the military applications and is to host a conference on hypersonic unmanned bombers. These bombers could be based in the US and yet strike from space at any place in the world within 2 hours. BBC has a report about these air/spacecraft that could be operational by 2025."

Comments

more info

[frieked]

Another story from The Guardian here ...And if your interested in another or Darpa's projects which might fall under the YRO category: here

Re:more info

[shthd]

Here ya go man... http://www.cnn.com/2003/TECH/ptech/07/01/arms.usa. reut/index.html

Re:more info

[mnemonic_]

Aerospike engines have nothing to do with hypersonic aircraft programs. Aerospike engines are important for their efficient exhaust plume that is created without a nozzle, hypersonic propulsion usually involves some sort of ramjet or scramjet. The X-33 was not military in any way, it was intended as a space shuttle replacement. You'll notice that the hypersonic aircraft look sleak and pointy, while the X-33 looks like a flying piece of pie with a blut nose. Obviously with such drastically different shapes they would have drastically different performance.

Sounds familiar, I'm skeptical..

[mysterious_mark]

I was in grad school as an aerospace/fluids engineer in the mid 90's during the aerospace boom (a bit like the dot-com boom). Hypersonic aircraft were on the drawing board but never made it. Turns out we didn't have a sufficient understanding of hypersonics. Building hypersonic wind tunnels and shock tubes is very difficult so computational models were used heavily. The computational models did not have sufficent validation due to lack of experimental data, so designing hypersonic vehicles turned out be a lot more difficult than originally thought. Also the materials problems in building aircraft that can tolerate the heat of hypersonic flight is still very significant. Titanium ceramic materials were developed, but manufacturing and machining with these materials was prohibitively expensive and difficult. Back then it the thinking was that the hypersonic modelling and material problems could be rapidly overcome and this technology was a few years off, it never happened though. I kust wonder if this is not just another Darpa pie-in-the-sky project where they are assuming difficult and unsolved problems can be surmounted. Guess we'll see if this project materializes, but I am skeptical. I think the Columbia disaster painfully illustrates the significant problems of hypersonic flight. MM

Re:Sounds familiar, I'm skeptical..

[anonymous loser]

A lot of the problem was that back then people would run their hypersonic CFD analysis, and some other group of people would run their hypersonic propulsion analysis, and another group would run their hypersonic structural analysis, and the dynamic interactions between these disciplines went uncaptured. These interactions between the disciplines are extremely important once you reach hypersonic speeds. A little bit of vibration in the wing can dramatically change the airflow over it, causing a cascade effect that is often unpredictable. Running the analyses separately means you often don't even realize such an interaction is present until you're very far along into the design process.

This effect is mitigated nowadays by tightly coupling the disciplines together into what is called multi-physics analysis. Since the finite element meshes used to model structures looks very different from the structures used to model airflow, for example, there is a lot of calculation behind the scenes that must correlate structural, thermal, and aerodynamic properties into a cohesive model.

Furthermore, the level of detail (number of nodes & elements in the mesh) required for proper hypersonics analysis is much higher than that of "normal" aircraft design. And, the inherently chaotic nature of hypersonics means that it is very difficult to show meaningful results without good probabilistics. Running probabilistic analysis on something so complex, however, requires serious computing resources. Computing resources even a few years later are many times faster now than they were back then, and many improvements have been made to the structure and methods used in parallelizing this kind of interdisciplinary calculation, such as the development of the SIERRA framework developed at Sandia National Labs.

Re:Aurora?

[e2d2]

I should hope it has built hypersonic aircraft. Otherwise there's been a huge conspiracy to mislead the public, and that concorde thing must be a hoax too.

Hypersonic is five times the speed of sound. The Concorde is supersonic only. Although the x-15 has been acknowledged as a hypersonic test platform it was:
A. A rocket
B. A test aircraft flown by NASA

To date there are no known flying hypersonic aircraft. Although there are a few test platforms for various airframes and engines (ramjets, wedge shapes, waveriders, etc) I know of no flying hypersonic aircraft that is public.

Reinventing the wheel?

[WegianWarrior]

You may not be aware of it, but most of this 'new' capabilities was avilable to the US in the late fifties, in the form of the Navaho intercontinental cruisemissile. True, it was a one way weapon on operational missions, but test missions were flown with retn to base.

It's funny... the US developed the Navaho based on the idea the germans had in the A4b / A9, which was contrived as a way to lenghten the range of the A4 (V2), only to cancel it and develop the Atlas ICBM wich offered the potential for longer range and shorter reactiontime... History seems to run in circles, just like a wheel...

Re:To me, this is sad.

[grasshoppah]

Quote: "Perhaps you'd care to name a nation that spends more on aid to other nations and their poeple than the USA does?"

oh oh let me!
Saudi Arabia gives a greater percentage of its gross national product to foreign aid that any other nation in the world. Following Saudi Arabia is Norway, Denmark, Sweden, and the Netherlands. Even countries like Luxembourg give 2x that of the United States. Per capita we spend less on forign aid than any of these countries. So what's so special about us? These countries are certainly not economic power houses but still manage to find the generosity to provide more of their money to forigners.

Re:Umm, don't we already have that?

[joshamania]

The Federation of American Scientists should have the info you're looking for...it may take some digging...their info-base is huge...

Re:An expensive solution to a non-existing problem

[Zemran]

Well, you _can_ win by just dropping bombs, but the price is pretty horrific.

That depends on your definition of 'win'. The Vietnamese would not see the US as winners, nor would Laos, Cambodia, Korea, Afghanistan and the jury is still out in Iraq but I doubt the US can win that one either. Killing lots of people is, more often, likely to lose the war. The only way to win is to earn the popular support of the people and that is something that the US has yet to learn how to do. Ghandi did it without an army and he beat the British when they were the strongest force on the planet.

If you're talking jazz, the situation is a no-win

[CausticWindow]

Percentage of budget of US foreign aid: 1.0% (dead last among western nations).
Percentage of that dedicated to military aid to allies: ~50% (to Israel, mostly)
Percentage of total aid that comes directly back to US companies: ~70%
Percentage of people polled that think we spend too much on foreign aid: 75%
Average response to the question, "how much should we spend on foreign aid?": 8.4%

What you reap is what you sow.

Re:An expensive solution to a non-existing problem

[slashdot_commentator]

The solution is not a pause button. Gulf War II took over a year to orchestrate. Hell, it takes months to build up a forward force before making an attack. You could see it coming months in advance.

No, this country needs educated, responsible citizens that understand the consequences (political, economic, and lives) of military action, and the will to look to alternate sources of information, now that the US media is owned by a few commercial military conglomerates.

It makes Christ's Second Coming a more likely event.

Re:Umm, don't we already have that?

[delong]

There's a US aircraft carrier within three days steam of any littoral point on the surface of the earth at any given time.

Problem is, once you get there, you need overfly rights from those pesky countries in the way. If your aircraft is in space, outside the national exclusionary zone, you can go wherever you please, and bomb the shit out of whomever you please, at will.

Derek