Alternative Propulsion Methods?

[JTM³]

Lately I've been wondering if there's more than two ways to fly...

 

I mean, we've gotten so used to prop/jet propulsion over the last few hundred years or so that I wonder if we've forgotten or never even though of revolutionary methods?

 

 

I've heard on a couple of tv programs that scientists are finding out that airplanes and boats have a lot in common or something; I guess like lift and boyancy are similar somehow?

 

 

Anyway, I've been thinking about magnetic propulsion systems.

 

Really creative stuff I think; like electromagnets spinning props that generate lift, or using magnets to somehow ionize the air and create lift that way; basically what flying involves is creating a low pressure above your craft allowing the high pressure below your craft to push you upwards.

 

Traditionally this has been accomplished through immense thrust from prop or jet engines.

 

However, I wonder if there are cheaper, more reliable, more creative solutions to achieving lift.

 

What do you think?

[padren]

Lately I've been wondering if there's more than two ways to fly...

 

I mean' date=' we've gotten so used to prop/jet propulsion over the last few hundred years or so that I wonder if we've forgotten or never even though of revolutionary methods?

 

 

I've heard on a couple of tv programs that scientists are finding out that airplanes and boats have a lot in common or something; I guess like lift and boyancy are similar somehow?

 

 

Anyway, I've been thinking about [i']magnetic[/i] propulsion systems.

 

Really creative stuff I think; like electromagnets spinning props that generate lift, or using magnets to somehow ionize the air and create lift that way; basically what flying involves is creating a low pressure above your craft allowing the high pressure below your craft to push you upwards.

 

Traditionally this has been accomplished through immense thrust from prop or jet engines.

 

However, I wonder if there are cheaper, more reliable, more creative solutions to achieving lift.

 

What do you think?

 

 

As for using electromagnets to spin a prop, that is an electric motor.

Creating a low pressure area above the craft would have to repel air particles away from the craft to generate - which would require an opposite and equal reaction that would likely force the magnet down away from the direction of the air particle in an equal or larger manner than the particle's lack of presence would create lift via vacuum. High pressure below would require you to be pulled toward the particle below you, with the same consequence.

 

I do think alternative ideas are good though: if we could ever find a means to effect all matter within a field equally with an equal force of propulsion for instance, we'd effectively negate g forces - a holy grail in rapid acceration for the traditionally g-force victimized occupants.

 

Ion drives do exist though and they were used in Deep Space 1.

 

Alertnative thought in propulsion is definately a good thing.

[Anjruu]

What about Space Sails? Those don't exist, but they are theorized, where a truely gigantic sail of some sort is erected to catch the solar "wind." Hard to get started, and I don't think it works well way from stars, but it is an idea.

[JTM³]

As for using electromagnets to spin a prop' date=' that is an electric motor.

Creating a low pressure area above the craft would have to repel air particles away from the craft to generate - which would require an opposite and equal reaction that would likely force the magnet down away from the direction of the air particle in an equal or larger manner than the particle's lack of presence would create lift via vacuum. High pressure below would require you to be pulled toward the particle below you, with the same consequence.

 

I do think alternative ideas are good though: if we could ever find a means to effect all matter within a field equally with an equal force of propulsion for instance, we'd effectively negate g forces - a holy grail in rapid acceration for the traditionally g-force victimized occupants.

 

Ion drives do exist though and they were used in Deep Space 1.

 

Alertnative thought in propulsion is definately a good thing.

 

Well, I was thinking more on the small scale for terrestial travel...ok, so I was inspiried by "343 Guilty Spark" from Halo. So what?

 

 

[SmallIsPower]

Is a mass driver a practical way for a plane to take off?

[Klaynos]

What about Space Sails? Those don't exist, but they are theorized, where a truely gigantic sail of some sort is erected to catch the solar "wind." Hard to get started, and I don't think it works well way from stars, but it is an idea.

 

They exist:

 

http://news.bbc.co.uk/1/hi/sci/tech/3555048.stm

[Rocket Man]

there are many ways to generate lift. a jet engine is actually less efficient than a prop because it is moving less mass of air (E=1/2 MV^2)

a jet aircraft uses the wings to create downwash and applies newtons laws to give lift. so it expends minimal energy keeping it off the ground and puts it's main efforts into keeping speed.

 

one way of producing lift is by ion wind. high voltage ionises air, then repels it at some velocity. VERY innefficient

 

there are designs for a magnetic hover craft, it uses ionised gas trapped under the base held under pressure with a magnetic feild. it's not really good for height though.

 

creative, reliable, cheap... look up the "gossamer albatross" on google

(just hope your legs hold up)

 

"Is a mass driver a practical way for a plane to take off?"

actually yes... especially if its kerosene powered and drives a mass of hot gas

[JTM³]

I really like the idea of magnetic propulsion.

 

I'm not thinking anti-gravity here; just an alternate way to achieve lift.

 

Alternate methods that allow the craft to be self powered; not like those laser craft and such.

 

Thanks rocket man! Good posts everyone.

 

 

Are you refering to lifters?

 

[CPL.Luke]

one way of producing lift is by ion wind. high voltage ionises air, then repels it at some velocity. VERY innefficient

 

^thats what a lifter does

 

and yes it is very energy inefficient as it accelerates a small mass to a relatively high speed, what you want to do in order to use less energy would be to accelerate a very large mass to a very low velocity.

 

hence a small propeller spinning very fast and hooked up to a 200HP engine on a plane produces less thrust than a very large propeller (spinning slower) thats hooked up to a 200HP engine

[SmallIsPower]

one way of producing lift is by ion wind. high voltage ionises air, then repels it at some velocity. VERY innefficient

 

Why did NASA use it on Deep Space One, they said the ion drive was ultimately powered by solar arrays. Why not directly by solar sails?

[CPL.Luke]

solar sails can only accelerate away from the sun, for most missions they want to accelerate in all directions, thats why they use the ion thruster. Its rare for an ion thruster to be used for speed (see promethius mission)

[Rocket Man]

the effect the lifters run on is disputed, most research says that the ion wind alone couldn't manage that force. it's probably just measurement errors though. the voltage used is capable of a lot of force. (i think that one in a vacuum wont do very much.)

 

i was actually referring to something else entirely. the physics seems right at first glance, though it doesnt look too promising:

http://www.hovertech.com/home/index.html

 

ion wind is VERY different to and ion rocket, an ion rocket pushes plasma at velocities comparable to C, ion wind applies an electrostatic force in air to attract air from one electrode to another, neutralise it, then leave it to continue on its merry way thus producing thrust.

i think that an ion rocket uses magnetics as well.

 

a solar sail is less powerful than an array and rocket.

radiation pressure provides less force than can be acheived by the same energy powering an engine.

i thought that this was for getting around in atmosphere, otherwise i would have suggested a magnetic sail to catch solar wind. (15km artificial magnetosphere catches moving ions kindly provided by the sun. much more effective than trying to catch light)

[JTM³]

the effect the lifters run on is disputed' date=' most research says that the ion wind alone couldn't manage that force. it's probably just measurement errors though. the voltage used is capable of a lot of force. (i think that one in a vacuum wont do very much.)

 

i was actually referring to something else entirely. the physics seems right at first glance, though it doesnt look too promising:

http://www.hovertech.com/home/index.html

 

[/quote']

 

Well, at least they give you 3 months to decide

 

What's not promising about it? If the physics work out it should only be a matter of time yes? Unless you mean that they aren't correct if you dig deeper?

[Rocket Man]

the way they expect to run the thing on NiCad batteries, high energy lazers drain a lot of juice, then they expect to hold an induced current in the plasma and repel it with an electromagnet. i would only expect a few minuites riding time.

perhaps with a scaled up power supply, but then it becomes ridiculous before it becomes practical.

im not going to attack the physics behind it, but the gear they're using ought to drain more power than they account for.

[bascule]

the effect the lifters run on is disputed, most research says that the ion wind alone couldn't manage that force. it's probably just measurement errors though. the voltage used is capable of a lot of force. (i think that one in a vacuum wont do very much.)

 

Whatever's happening, it's some sort of electromagnetic reaction with air molecules. Turn on a lifter inside a vacuum and... nothing.

[Rocket Man]

Whatever's happening, it's some sort of electromagnetic reaction with air molecules. Turn on a lifter inside a vacuum and... nothing.

 

what else could it repel so as to not violate newtons laws?

it might simply be that we havent looked at all the possibilities, science claimed that a bumble bee couldnt fly untill the reasearchers analysed the vorticies near the edges of the wing.

i did read, however, that these devices work best in very low pressure. (much the same as the "light mill", works well in low pressure, fails completely in a vacuum)

[5614]

RocketMan: can you give me a reliable source which talks of this dispute between scientists regarding the explanation for lifter's lift. I read about them, although it was a few months ago, but the way I remember it scientists were certain it was ionic wind that caused the lift...

[CPL.Luke]

it is possible it could get a very very very low amount of thrust in a vaccuum as electrons could possibly escape the system and generate a bit of thrust

[Rocket Man]

RocketMan: can you give me a reliable source which talks of this dispute between scientists regarding the explanation for lifter's lift. I read about them, although it was a few months ago, but the way I remember it scientists were certain it was ionic wind that caused the lift...

 

 

sorry, i cant give any "reliable" source for the dispute, most of what i heard was from crackpots and idoits, i myself am certain that this is ion wind. the tests i've seen done are not in any way conclusive.

[In My Memory]

You could try wandering through the desert until you stumbled upon a magic lamp, and then wishing for a flying carpet. Or if you're in a really playful mood, a big big slingshot.