Electrical power based jet fighters...?

[Singular Intellect]

The thread title basically says it all...is it possible to design a combat performance jet fighter that could utilize electical power to generate it's thrust as opposed to current fuel designs? Unless I'm mistaken, current fighters are dependent upon the high pressure exhaust of burning fuel to generate their high thrust capabilities...could an electrical jet engine be designed and built to provide the same results? Theoritically?

For the sake of arguement, let's assume battery weight/energy potential isn't an issue and could fit into current fuel tank volumes with equivalent or better operational ranges for the craft in question.

[Hawkwings]

How would you heat up the air using electrical power?

[Sea Skimmer]

Well that would be a matter of packing the required electrical heating elements into a pretty small space. The moving parts of the engine would actually be better off, since pure hot air is far less corrosive then burning fuel. I’m sure you could build a working electrical jet engine, but I very highly doubt you can get enough electrical heat into the thing to reach the power levels of military turbofan engines. Matching the thrust of full reheat would be especially difficult.

[Civil War Man]

For the sake of arguement, let's assume battery weight/energy potential isn't an issue and could fit into current fuel tank volumes with equivalent or better operational ranges for the craft in question.

Well, when you work under those parameters, it's possible. The trouble is we are not nearly at that level of technology.

Here are a few possible complications, ignoring the obvious ones like weight.

First, refueling, particularly mid-flight refueling. It's going to be more complicated (and dangerous) to recharge the batteries if you want to be able to operate the plane at the same time.

Secondly, operational range is very heavily affected by the operational speed (probably moreso than with gas vehicles, though I don't have numbers to say either way). So basically, if you hit the afterburners, you are going to start sucking power out of the batteries much, much quicker than you would at cruising speed.

And on the note, consider that the engines and the controls are going to be drawing off the same power source. So if you are really running low on juice, you are pretty right fucked.

[Fingolfin_Noldor]

I don't think there's any heating elements that can deliver enough heat to do a rapid expansion of air in a jet engine.

[Fingolfin_Noldor]

EDIT: It might be possible to have tonnes of it, but there are real questions of wear and tear to be dealt with. The more heating elements you might have, the higher possibility of the whole bloody lot burning out and then the aircraft is in serious trouble.

[Zixinus]

If you can speed up electrons to relativistic velocity, and compress air well enough, and inject the relativistic electrons, you may have something.

[JointStrikeFighter]

You could also use electricity to ionise the air and then electromagneticly accelerate it out the back.

[Starglider]

Has many of the same problems as the nuclear spaceplane booster someone just proposed; using your electricity to electrolyse water into hydrogen is a much more practical idea. There is no known or predicted battery technology that rivals the energy density of cryogenic hydrogen, and a fuel cell plus electric heaters would just be pointless extra weight. It will be very difficult to get good heat transfer between the heaters and the airflow anyway, without a large number of very fine elements that create extreme drag.

[Winston Blake]

I think you'd be better off with a chain of big fat arc lamps, rather than using heating elements. This is simply replacing 'flame' with 'spark'. Higher temperatures may improve some minor aspect of efficiency, but that's about the only positive thing I can think of. Maintaining the arc at supersonic speeds is left as an exercise for the reader.

[Ted C]

For the sake of arguement, let's assume battery weight/energy potential isn't an issue and could fit into current fuel tank volumes with equivalent or better operational ranges for the craft in question.

Assuming you can generate the power and the voltage, I suppose that you could force current to arc through an airspace. Given the high resistance of air, you should generate pretty massive amounts of heat that will force the air to expand rapidly. If you can get enough of this superheated air moving in the right direction, you've got plenty of thrust.

I suppose that a valve system would be required to keep expanding are from escaping through the intakes, reducing your efficiency.

I have no idea how practical this would be, though, since I really have no idea what kind of power will be needed to basically superheat air to plasma in sufficient quantities. We're basically talking about lightning in a jar, here.

[Admiral Valdemar]

I would expect more modern nuclear thermal direct and indirect systems to be the best you could do without something like AM as a power source. You aren't getting traditional chemical batteries doing this, and even fuel-cells are only capable as being auxiliary power sources in airliners and some light planes as a main power source (though still iffy).

A fusion turbine would be better, but again, you need to have the technology to get the fusion system small enough to be practical for good thrust-to-weight ratios and that would like require AM ignition.

[sketerpot]

Probably a better application for this sort of thing is making aircraft that can stay aloft for a very long time, because they have a nuclear reactor powering them. It works for nuclear submarines, which only have to refuel the reactor every 20 years or so.

[Starglider]

Probably a better application for this sort of thing is making aircraft that can stay aloft for a very long time, because they have a nuclear reactor powering them.

As Admiral Valdemar pointed out, an electrical system is going to be much less efficient and (barring magic-tech like insanely efficient thermocouples) much heavier than a direct thermal power transfer system (from the reactor to the thrusters).

[Lord of the Abyss]

You could also use electricity to ionise the air and then electromagneticly accelerate it out the back.

That sounds like an air using version of a Magnetoplasmadynamic thruster.

There's also the idea of an "air spike" being used to compress air for the engine; an air spike being a laser or microwave beam that heats the air enough to produce a shockwave that pushes much of the air out of the way and reduces stress on a supersonic aircraft; supposedly it's possible to design it so that the shockwave is used to compress air for an engine as well. The guy who came up with this idea wanted to power the aircraft by ground based microwaves ( producing ionised air inside the engine for conversion into thrust ); I suppose you could use an onboard engine if you had the power source for it. IIRC NASA was interested in a "Cool. It might work in another fifty years" sort of way.