Magneto Hydrodynamic Propulsion for hypersonic aircraft?


by Cliff_J
Tags: aircraft, hydrodynamic, hypersonic, magneto, propulsion
Cliff_J
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#1
May3-04, 03:27 PM
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I watched a "Black Aircraft" show on the science channel. In the show they mentioned a researcher working on old Russian technology that placed a strong beam in front of the aircraft to strip electrons from the air molecules so the plasma creates its own initial shockwave to lessen drag on plane. Then electro-magnets located inside the aircraft would accelerate the ions in the air as MHD to provide 1/2 the thrust.

As a few in here seem to follow the X43 and SCRAMjet, and I ask if this is even possible much less probable?

One person interviewed on the show said that the Russian prototype was clocked at mach 12 and mach 16 by some european radar operator. That would make the X15 some sort of flying yugo in comparison at what, a measely mach 6 or whatever it reached before the program was canceled?

So what do you guys think: Is this some leftover cold-war propaganda mixed with science fiction??
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Lord Flasheart
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#2
May3-04, 04:17 PM
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Personally, I feel that the research into SCRAMjets and other genius, but not practical ideas, is hyped up. Given a wee bit more money, they would certainly seem more economical for various purposes. But NASA is running on a tight budget, and they cannot afford to delve into new ideas, even with the Bush-Expansion proposal. They've gone to "probe-dom", an idle state where they don't like the challenges of manned missions, and instead shoot out mindless automata every few years or so. Sure, the U.S.A.F or the U.S.N. will find a use of the X-43 or similar systems, but it still needs a rocket to boost it up to a velocity where the SCRAMjet will work properly. Simplicity is needed. Using electron guns or lasers to ionize the air in front of a jet is quite intriguing, but not practical. Plasma propulsion is too weak in the atmosphere, unless it can pulse it or make highly dense ion-clusters. Even then, the 'craft would be so heavy, you couldn't get it off the ground.

I am all for advanced propulsion systems, but you have to keep them simple as possible. It's as if that propulsion system was trying to put wheels on a spherical object.

Over and out.
LURCH
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#3
May4-04, 02:28 PM
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I don't think this vehicle ever actually flew. If it had, the news would have been mainstream by now. Mach 15/16 is a huge achievement, and would have been all over the news and the sci-tech websites. I doubt that MDP (Magneto Hydrodynamic would mean using water to propell the craft) could provide an appreciable amount of thrust for atmosopheric craft.

One (very minor) correction to LF's post; a SCramjet does not need a rocket to get up to operational speed, any more than a ramjet does. The X-43 used one because it was just a proof-of-concept prototype. Actuall aircraft using this type of engine will simply be ramjets that don't flameout at Mach 4 or 5.

Lord Flasheart
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#4
May4-04, 03:46 PM
P: 94

Magneto Hydrodynamic Propulsion for hypersonic aircraft?


Mea culpa, LURCH.

If I remember correctly, the phrase Magneto-Hydrodynamic in reference to plasma means that it uses the fluid action of ionized gas to provide power and/or thrust. Passing plasma by superconducters gives energy to them, which could be quite useful for spacecraft combining propulsion with electrical needs.

Over and out.
LURCH
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#5
May5-04, 02:48 PM
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Yes, I find this field of space-propulsion research very exciting, as well. I've often wondered if the very powerfull magnetic field involved could also be used to help protect cosmonauts from radiation?
Lord Flasheart
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#6
May5-04, 04:51 PM
P: 94
The superconducters could be an excellent secondary mag-shield in case a solar flare is imminent. However, a better shield is possible, and it also provides easy movement through space. Mini-Magnetospheric-Plasma-Propulsion, or M2P2. Powered by the solar wind, it can speed a ship to high speeds, and slow it down as well, quite like a solar sail. By inflating a plasma with a solenoidal magnet, it would encompass tens of kilometers in space, with a magnetosphere rivalling our own dear Earth.

Over and out.
drag
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#7
May8-04, 11:10 AM
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Greetings !
Quote Quote by LURCH
Yes, I find this field of space-propulsion research very exciting, as well. I've often wondered if the very powerfull magnetic field involved could also be used to help protect cosmonauts from radiation?
It can't stop EM radiation and I doubt it can stop cosmic
rays unless the field is VERY powerfull. So I guess it's impractical
for now. It's also useless against nutrons (if you fly up a reactor
with you).

I've seen some patents involving various variations of
electromagnetic propulsion used in the atmosphere. I don't
believe it's practical, at least not until we have portable
fusion generators - like in Back to the Future 2.

As for creating a shock wave in front of the aircraft -
sort of like clearing out the way, that's an intresting idea,
but I'm not sure how this could be achieved. Either you
use lasers or electromagnets or something like that - which,
again, needs lots of power, or maybe you could use chemical
energy - shooting small explosives or hydrogen or something, but
that requires some serious R&D and could still end up being
innefficient. Then again, burning a few gallons of fuel per second
is not that effecient either - so who knows.

I also think that those ideas about injecting nitrogen to
"smooth" the drag are intresting. The may even become
a must for hypersonic craft - to prevent overheating and
long term hull damage, or allow the use of cheaper materials
for the hull. We'll have to wait and see.

Live long and prosper.
russ_watters
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#8
May8-04, 11:26 PM
Mentor
P: 22,008
Quote Quote by Lord Flasheart
If I remember correctly, the phrase Magneto-Hydrodynamic in reference to plasma means that it uses the fluid action of ionized gas to provide power and/or thrust.
The first time I ever heard that term was in the movie The Hunt for Red October. That's the propulsion the sub used - and it does exist. A few years back, a prototype ferry was built in Japan that used it - it topped out at a blistering 2 (two) knots.

No, a mach 15 plane does not exist. I personally don't think there will ever be an atmospheric plane to fly over about mach 6. The SR-71 once accidentally hit about mach 4 before things started melting and its made of titanium. The space shuttle hits its max heating at something like 10,000 mph and 100,000 feet and couldn't do it for more than a couple of minute.

The point is, if you're going to get up to about 75% of orbital velocity, its self-defeating to stay in the atmosphere: you may as well go sub-orbital in space.
drag
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#9
May9-04, 01:02 AM
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But in space you need to carry your own propellant
and use rockets or something, so you loose the potential
low costs and mass advantages.

I believe that if scramjets are improved enough to actually
proppel passanger flights, the issue of friction and overheating
will be quickly solved. Either they'll use new materials, new
geometry or gases or maybe something new. Either way,
when you waste tiny amounts of fuel and can get your
passengers half way around the world in two hours -
it'll be worth it, I think.

BTW, about MHD submarine propulsion, I read that their
greatest problem is with the magnetic field strenght. After all,
nuclear subs already got enough power. I think that
with all recent improvements in superconductors and
with the new superconducting light-weight and compact
equipement, like the motors being developed by a US
company for the navy for example, this propulsion system
has high potential for future nuclear subs.

Live long and prosper.


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