atmospheric plasma thruster

[Nuke]

https://newatlas.com/aircraft/microwave-air-plasma-thruster/

found this in my hack--a-day links today. its at atmospheric plasma thruster design that is supposedly more efficient that jet engines. of course we have some way to go before we board airliners with plasma thrusters.

[magnemoe]

4 hours ago, Nuke said:

https://newatlas.com/aircraft/microwave-air-plasma-thruster/

found this in my hack--a-day links today. its at atmospheric plasma thruster design that is supposedly more efficient that jet engines. of course we have some way to go before we board airliners with plasma thrusters.

Problem is powering the thing. This don't need fuel but it need power to run.

[Spacescifi]

1 hour ago, magnemoe said:

Problem is powering the thing. This don't need fuel but it need power to run.

 

That maybe can be solved with nuclear reactors.

 

Really though... probably would be radioactive, but it could probably work.

I mean the TWR is going to be low no matter what, so large wings 747 style and nuclear airbreathing to boot with the microwave induced plasma may be enough.

And if we ever figure a more efficiebt way of antimatter production and atorage then it is a given that we can do the plasma jet thing.

Still going to have low TWR though, since air lacks the mass flow density of liquid or solid propellant.

[sevenperforce]

10 hours ago, magnemoe said:

14 hours ago, Nuke said:

https://newatlas.com/aircraft/microwave-air-plasma-thruster/

found this in my hack--a-day links today. its at atmospheric plasma thruster design that is supposedly more efficient that jet engines. of course we have some way to go before we board airliners with plasma thrusters.

Problem is powering the thing. This don't need fuel but it need power to run.

The real challenge to this is the losses in ionizing the air in the first place. It's called a "low temperature plasma" because the electrons in the flow stream are at a different temperature than the rest of the fluid, but they still have a tremendous amount of energy. Air is not particularly happy about being ionized so it takes huge amounts of voltage to do it, and all the energy is wasted when the ions are fired out the back end.

However, if there was a way to grab the ionized particles, they could be routed back around to the front end to offset the required voltage potential. That idea has...potential.

You'd need a compressor fan at the front terminating in a high voltage drop to ionize the compressed air. You'd then use microwaves to heat it in a "combustion chamber" a la a conventional turbojet engine, and it would be expelled out the back end. You'd need to mix with compressor bypass to augment the thrust, then collect the ions in the rear of the thrust chamber while the accelerated un-ionized air roared out.

An ionocraft works in a similar way: the ions themselves are not producing thrust, but rather they are bumping into ambient air to create ion wind and are then collected. But the force imparted to the ambient air is a function of the voltage drop, and it requires ridiculous amounts of voltage to ionize in the first place. This concept, on the other hand, would use microwaves to beef up the force imparted to the ambient air, so the voltage drop remains low (and can even be recycled).

9 hours ago, Spacescifi said:

That maybe can be solved with nuclear reactors.

Nukes are not known for being helpful at creating low-temperature plasma. Or at creating electricity, unless you have a ton of coolant.

[Spacescifi]

5 hours ago, sevenperforce said:

The real challenge to this is the losses in ionizing the air in the first place. It's called a "low temperature plasma" because the electrons in the flow stream are at a different temperature than the rest of the fluid, but they still have a tremendous amount of energy. Air is not particularly happy about being ionized so it takes huge amounts of voltage to do it, and all the energy is wasted when the ions are fired out the back end.

However, if there was a way to grab the ionized particles, they could be routed back around to the front end to offset the required voltage potential. That idea has...potential.

You'd need a compressor fan at the front terminating in a high voltage drop to ionize the compressed air. You'd then use microwaves to heat it in a "combustion chamber" a la a conventional turbojet engine, and it would be expelled out the back end. You'd need to mix with compressor bypass to augment the thrust, then collect the ions in the rear of the thrust chamber while the accelerated un-ionized air roared out.

An ionocraft works in a similar way: the ions themselves are not producing thrust, but rather they are bumping into ambient air to create ion wind and are then collected. But the force imparted to the ambient air is a function of the voltage drop, and it requires ridiculous amounts of voltage to ionize in the first place. This concept, on the other hand, would use microwaves to beef up the force imparted to the ambient air, so the voltage drop remains low (and can even be recycled).

Nukes are not known for being helpful at creating low-temperature plasma. Or at creating electricity, unless you have a ton of coolant.

 

Wait... could we not use a long helicopter blade spun by the reactor to generate the needed electricity?

Last I checked turbines and fans share some things in common, one being that BOTH can be harnessed to generate electricty.

Just about any motion can. I can even do it on an electric rechargable bike!

The only working fluid we have that we don't have to pay cargo space for is air. May as well use it to our advantage.

I am betting we can use some way to use the local air to generate the energy.

Barring that?

Batteries that hold vaster amounts of energy than they do now... which also makes them more combustible.

Edited May 11, 2020 by Spacescifi

[sevenperforce]

14 minutes ago, Spacescifi said:

Wait... could we not use a long helicopter blade spun by the reactor to generate the needed electricity?

Last I checked turbines and fans share some things in common, one being that BOTH can be harnessed to generate electricty.

Just about any motion can. I can even do it on an electric rechargable bike!

How do you propose to make a nuclear reactor spin anything, or produce motion of any kind?

14 minutes ago, Spacescifi said:

The only working fluid we have that we don't have to pay cargo space for is air. May as well use it to our advantage.

I am betting we can use some way to use the local air to generate the energy.

The local air is useful reaction mass but is not going to generate any energy.

[jimmymcgoochie]

Project Pluto was an experiment in the early 60s that used a nuclear reactor to replace the combustion part of a jet engine, generating the heat needed to provide thrust with nothing but air being used as fuel (well, air and some uranium undergoing nuclear fission). Prototypes were successfully tested and as the only real limits were the fuel in the reactor a design like this would have effectively unlimited range, but who would actually pay to sit on a plane that was powered by nuclear reactors? (It was designed to power cruise missiles, not airliners)

And as for antimatter- it's totally overhyped. Making antimatter requires lots of energy and by definition only half of that energy becomes antimatter as the other half becomes matter; separating antimatter from regular matter requires more energy; any tiny failure of containment will result in antimatter meeting matter and annihilating each other releasing all that energy again, so any antimatter storage is basically a bomb; and even assuming you can overcome all those limitations, the radiation released by matter-antimatter annihilation is quite possibly even more dangerous than from a fission reactor so you'd need even more radiation shielding to protect against it.

[Spacescifi]

49 minutes ago, sevenperforce said:

How do you propose to make a nuclear reactor spin anything, or produce motion of any kind?

The local air is useful reaction mass but is not going to generate any energy.

 

Not if you do not try no.

 

Electric windmills exist.

 

Now I honestly do not know what it would take to generate enough wind for the power required.

My guess? A rocket stage booster and have blades sideways cutting into wind to get windpower for free.

It will take a long, long blade, and probably several staged boosters because of weight.

 

Would look very cool though.

Look at the double flying blades of death with a blue plasma plume behind the fuselage!

Edited May 11, 2020 by Spacescifi

[RCgothic]

You can't get wind power for free that way. It would consume more energy in drag than it would generate in additional thrust because the 2nd law of thermodynamics doesn't let you get away with stuff like that.

[Spacescifi]

9 minutes ago, RCgothic said:

You can't get wind power for free that way. It would consume more energy in drag than it would generate in additional thrust because the 2nd law of thermodynamics doesn't let you get away with stuff like that.

 

It's not for thrust. It is to generate electricity for ionization of the air.

If all I wanted was thrust then project pluto is the answer.

I am trying to find a solution to the OP.

Whatever might work... could work. Even if not efficient.

Really though... I think combining the technology of project pluto with the ionized plasma jet somehow could be quite the air vehicle.

 

Someday... future.

Edited May 11, 2020 by Spacescifi

[mikegarrison]

54 minutes ago, jimmymcgoochie said:

Project Pluto was an experiment in the early 60s that used a nuclear reactor to replace the combustion part of a jet engine, generating the heat needed to provide thrust with nothing but air being used as fuel (well, air and some uranium undergoing nuclear fission). Prototypes were successfully tested and as the only real limits were the fuel in the reactor a design like this would have effectively unlimited range, but who would actually pay to sit on a plane that was powered by nuclear reactors? (It was designed to power cruise missiles, not airliners)

It's hard to claim that "prototypes were successfully tested". They tested "engines" that were so big and heavy that they needed to be mounted on rail cars, and they only operated for a few minutes at most.

Russia has recently announced it is working on this same idea (a nuclear ramjet engine for a cruise missile).

[Spacescifi]

10 minutes ago, mikegarrison said:

It's hard to claim that "prototypes were successfully tested". They tested "engines" that were so big and heavy that they needed to be mounted on rail cars, and they only operated for a few minutes at most.

Russia has recently announced it is working on this same idea (a nuclear ramjet engine for a cruise missile).

 

Are you talking about the recent radioactive disaster involving several deaths and a missile of theirs?

11 minutes ago, mikegarrison said:

It's hard to claim that "prototypes were successfully tested". They tested "engines" that were so big and heavy that they needed to be mounted on rail cars, and they only operated for a few minutes at most.

Russia has recently announced it is working on this same idea (a nuclear ramjet engine for a cruise missile).

 

Perhaps.

Even so, do you not think we can do better with current tech?

Lighter, faster, harder?

[Nuke]

19 hours ago, magnemoe said:

Problem is powering the thing. This don't need fuel but it need power to run.

i think the idea is that solid state batteries would have the energy density for short hop flights. of course that could be a decade or more of development before we start seeing them in devices and another before we start seeing massive ev packs. add another for airliner sized packs. 

Edited May 12, 2020 by Nuke

[Nuke]

i figured it would take about 6.4 MW of electrical power to make this kind of thruster power a 737, and thats not counting the added weight of the engine or the batteries or whether a battery pack could put out 6.4 MW with current tech. 

[Guest]

Well, 6.4 MW is pretty much in the right ballpark for a nuclear reactor that you could cram onto a 737-sized airplane, though it would likely leave too little space for other things. However, it's probably more efficient (and simpler) to have the reactor spin a fan or produce thrust directly in a thermal turbojet. Adding an electricity-generating step in the middle clobbers your efficiency, and the waste heat needs to be dealt with, anyway.

Edited May 12, 2020 by Guest

[jimmymcgoochie]

14 hours ago, mikegarrison said:

It's hard to claim that "prototypes were successfully tested". They tested "engines" that were so big and heavy that they needed to be mounted on rail cars, and they only operated for a few minutes at most.

Russia has recently announced it is working on this same idea (a nuclear ramjet engine for a cruise missile).

They produced thrust, which for a machine built to produce thrust is the definition of success. Russia’s attempt to do the same exploded and caused several fatalities and a huge increase in radiation in local urban areas, which is quite clearly not a successful test.

[Guest]

It's not the first time this missile flew, though. The technology works, it's just that something went badly wrong that time. It's not easy to blow up a nuclear reactor like that. The Russian missile probably wasn't really like Project Pluto (though admittedly, it's not entirely clear what it actually was).

BTW, while Pluto engines were railcar mounted, it was done to hold them down. Also, there was presumably a lot of overhead from equipment needed to test-run a ramjet at zero airspeed at sea level. These are not normal operating conditions for such an engine, Pluto would have been launched using a solid booster.

[kerbiloid]

We can make an antimatter-powered fan, make wind, and catch it by a wind turbine to produce energy to produce the antimatter.

[sevenperforce]

2 hours ago, kerbiloid said:

We can make an antimatter-powered fan, make wind, and catch it by a wind turbine to produce energy to produce the antimatter.

[magnemoe]

17 hours ago, Nuke said:

i think the idea is that solid state batteries would have the energy density for short hop flights. of course that could be a decade or more of development before we start seeing them in devices and another before we start seeing massive ev packs. add another for airliner sized packs. 

Yes but for short flights propeller or fan is far more effective. Don't see an use for pure jets unless you go supersonic. 
And I think that unlike electrical propellers who is more effective than an IC or turbine powered propeller this design will probably be less effective than an jet engine running on jet fuel.

And yes with better batteries battery powered planes might become an thing for shorter routes. Not only would fuel cost be lower but the plane could be cheaper to run because its easy to add redundancy with an electrical systems.  Take 4 propellers put 4 battery packs behind them. 
You could obviously cross-feed, you might even shut down and stove the outer propellers at cruise but you are still an 4 engine plane. Option to drop battery pack if it catch fire, you could even set it up swap batteries. Unlike cars planes has already dedicated support systems at airports for doing stuff like loading cargo fast and swapping batteries would like changing weapon layout on an F-22 or other planes with an small internal weapon bay but easier as the pack does not need to be aerodynamic. If you can not swap you could always recharge the traditional way. 
 

[Nuke]

5 hours ago, magnemoe said:

Yes but for short flights propeller or fan is far more effective. Don't see an use for pure jets unless you go supersonic. 
And I think that unlike electrical propellers who is more effective than an IC or turbine powered propeller this design will probably be less effective than an jet engine running on jet fuel.

And yes with better batteries battery powered planes might become an thing for shorter routes. Not only would fuel cost be lower but the plane could be cheaper to run because its easy to add redundancy with an electrical systems.  Take 4 propellers put 4 battery packs behind them. 
You could obviously cross-feed, you might even shut down and stove the outer propellers at cruise but you are still an 4 engine plane. Option to drop battery pack if it catch fire, you could even set it up swap batteries. Unlike cars planes has already dedicated support systems at airports for doing stuff like loading cargo fast and swapping batteries would like changing weapon layout on an F-22 or other planes with an small internal weapon bay but easier as the pack does not need to be aerodynamic. If you can not swap you could always recharge the traditional way. 
 

i see a lot of electric plane concepts with multiple small props. yet all the commercial sport offerings seem to be single motor affairs. the simplicity of a single drive shaft with a rotor (just a ring of neodymium magnets) and prop on a pair of berings puts most of the aircraft engines to shame in terms of simplicity. of course since redundancy is essentially free, bring a couple. but you see concepts bristling with small props and it just seems laughable. the place where you actually want the redundancy is in the battery. multiple banks any one of which provide enough power to maintain altitude. would probably enable all but a couple banks for takeoff, and then switch down to one or two durring flight or alternate between them to manage heat. perhaps do some minor range extension by installing thin film solar panels on the upper wing and fuselage.