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Comments on: NASA pondering electro-hypersonic jet boosters

Or... 

Posted Monday 3rd December 2007 13:49 GMT

Joke

It could give me the billions of pounds it spends on this venture and end up with the exact same results as they will if they attempt this.

Chris

MHD 

Posted Monday 3rd December 2007 14:02 GMT

Boffin

Anyone curios at how odd MHD really is should wander over to Jean Lous Naudins (http://jnaudin.free.fr/lifters/main.htm) website for some freaky demos.

PS. dont try the Microwave plasma balls in the missus cooker she wont like it!

War rocket Ajax?! 

Posted Monday 3rd December 2007 14:58 GMT

Paris Hilton

Wasn't that going to be used to 'Bring back his [flash gordon's body]?'

re: War rocket Ajax?! 

Posted Monday 3rd December 2007 15:17 GMT

I always *thought* she sounded Russian. Now we know!

What's the point? 

Posted Monday 3rd December 2007 15:48 GMT

Black Helicopters

Great, London to New York in 3 days and a few minutes (3 days pre notice), then 3 days in customs because your teddy bears name is NOT Mohammed, so clearly you are terrorist!

Uhh...Ramjets??? 

Posted Monday 3rd December 2007 16:03 GMT

"conventional (but brutal) J-58 turbojets"

What???

The J-58 is a turbofan-ramjet hybrid engine and is anything but conventional.

You're thinking of the MiG-25 which has "conventional but brutal", enormous turbojets that would fuck themselves to pieces at mach 3 speeds, ruining the jet.

Plumbing the depths 

Posted Monday 3rd December 2007 16:52 GMT

Wasn't the Caterpillar Drive on Red Oktober a form of MHD?

Don't need to accelerate! 

Posted Monday 3rd December 2007 17:05 GMT

Happy

You don't need to accelerate to "Mach 25+" to reach orbit. In fact, you don't need to accelerate at all. As long as your craft can get you off the ground and can maintain a steady push, you can reach orbit at any speed. The issue is what speed you attain when in orbit, to stop yourself from being pulled back down to earth and being reduced to a hot, steaming, metal lump.

the lifter 

Posted Monday 3rd December 2007 17:10 GMT

Yes, it's impressive. That remembers me how Jean-Pierre Petit, a french physician, explained the possible use of the MHD by the flying-saucer.

Perpetual Motion 

Posted Monday 3rd December 2007 17:15 GMT

Alien

"...So, like, we ionise the air infront of the intake with this, like, device, yea? Then we take the ions back out of the air with this other device, yea, which makes electricty, right, yea, and we use the electricty to power the first device, ok? And your, like, going to pay me lots of money, yea? Cool!"

Re: Plumbing the depths 

Posted Monday 3rd December 2007 17:42 GMT

That was fiction (and, BTW, only in the movie, the novel used a different technique), but they've done it for real:

http://en.wikipedia.org/wiki/Yamato_1

@Stu Reeves 

Posted Monday 3rd December 2007 19:58 GMT

I don't suppose they can make a case for commercial applications as they would lose the drinks trolley sales.

Nuclear warheads? 

Posted Monday 3rd December 2007 19:59 GMT

What's this about putting nuclear warheads in orbit? Sheesh, let's have some accurate reporting, eh? There is a limited history of weapons in space - the Soviets put some on the Almaz military stations. And the Soyuz capsule is always equipped with a triple-barreled "survival gun".

@Androski - if you're not going fast enough to miss the ground as you get pulled back down to earth, you're not in orbit. It's very simple.

@Dom 

Posted Monday 3rd December 2007 22:52 GMT

They don't get the survival gun anymore. They ran out of ammunition for it.

They just get a normal pistol now.

@Dom 

Posted Monday 3rd December 2007 23:11 GMT

Joke

It's called "taking the piss", mate.

Hmmm... 

Posted Tuesday 4th December 2007 01:57 GMT

@Androski - 'Orbiting' is different than hovering-really-high. And hovering is typically more more energy intensive than standing on a table.

Are they claiming that they can extract the energy from the front and use it at the back?

These boffins should perhaps review Thermodynamics 101:

1. You can't win.

2. You can't break even.

3. You can't quit.

Just too easy 

Posted Tuesday 4th December 2007 02:06 GMT

Flame

If you want to make your own plasma the simple answer is fire two 5000w microwave emitters at each other (roughly), the atmosphere at the point(s) in space where they are in phase will be reduced to plasma - actually it forms into plasma balls, but who's counting. Normally these man made lightening balls will seek out something earthed and/or metallic, but a few good magnets/electromagnetic fields should keep them in check - plus moving forward very quickly.

Actually another option if you're moving forward very fast is to push something sacrificial into the shock front (or whatever the term is) with the aim that the heat generated will convert it to a plasma stream. Think along the lines of a MIG welder.

Now what I really want to see is someone do a proper pulse detonation engine (that I can make in my backyard) not just a run of the mill pulsejet. Personally I think scramjets are overrated.

If access to space is ever to become easier 

Posted Tuesday 4th December 2007 08:31 GMT

Then Earth's orbit is going to need a serious cleaning. The thousands of nuts, bolts and assorted debris that are floating around up there will be a navigational hazard of much greater importance if the traffic is multiplied by civilian activity.

Thermodynamics 

Posted Tuesday 4th December 2007 15:18 GMT

@JeffyPoo

Quite right about not being able to get something for nothing, but I think your interpretation is slightly off.

What happens in a normal jet engine is that the airflow is "slowed down" relative to the plane, which converts some of the planes kinetic energy into heat.

What they are trying to do here is convert some of it into electricity instead, which they can then convert back to kinetic energy by using it to boosting the exhaust.

Each step will cost energy, as you can't get anything for free, but they are hoping that they will be able to make it efficient enough to be worth the effort.

To summarise: the energy they are trying to tap is in the system already, and it is only going to be lost as heat anyway.

re: JeffyPooh 

Posted Tuesday 11th December 2007 00:43 GMT

Coat

JeffyPooh writes:

> These boffins should perhaps review Thermodynamics 101:

> 1. You can't win.

> 2. You can't break even.

> 3. You can't quit.

or:

"the wheel is turnin' and you can't slow down,

you can't let go and you can't hold on;

you can't go back and you can't stand still..."

--jerry garcia.

Uhm, yeah; mine's the big tie-dyed mohair one, thanks.

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