# The Naked Scientists Forum

### Author Topic: Is magnetic flight possible?  (Read 2537 times)

#### ScientificSorcerer

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##### Is magnetic flight possible?
« on: 05/02/2015 11:52:23 »
I saw this video and realized that this craft must have been using a high powered magnetic field for some reason and it inspired me to ask this question. Is magnetic/electromagnetic flight possible?

I mean to say is it possible to "magnetically levitate" an aircraft far into the sky like an airplane?

Take a look at the video as an example

If you look carefully, the water forms a concave hole in the water before the craft even touches it, indicating a high powered magnetic field.  You see ocean water is conductive and when the high powered magnetic field which is surrounding the craft came close to the water at high speed it induced an electrical current into the water called an eddy current which caused the electrified water to produce a magnetic field in such a way that the water became repelled by the ship's magnetic field pushing it downward.

this video shows the effect, it's a type of "induction"

If that conductive solid in the second video was replaced by a conductive liquid such as salt water, it would cause a dip or hole to occur in the liquid which is what was seen in the video. But that's besides the point, the point is that this craft may have a magnetic field around it and that it's propulsion may depend on it.

Let's just say it was real, how could it possibly work? How could any form of magnetic/electric aircraft work?

I can only speculate, so can all who read this. so don't take these words too seriously.  It's just a fun science topic.
« Last Edit: 05/02/2015 12:01:16 by ScientificSorcerer »

#### chiralSPO

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##### Re: Is magnetic flight possible?
« Reply #1 on: 05/02/2015 16:34:39 »
I suppose it should be possible to levitate an object very high up using a magnetic field. I think the problem is the amount of energy required to do that. The force between two magnets falls off as the cube of the distance, so if you have a pair of magnets that can levitate something one foot off the ground, you would need to increase the strength of those magnets by 9 orders of magnitude to get it to levitate 1000 feet off the ground. The magnets would also wreak havoc on everything else around them (not to mention that magnets so strong would probably rip themselves apart).

#### evan_au

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##### Re: Is magnetic flight possible?
« Reply #2 on: 08/02/2015 20:12:41 »
I have traveled on the Shanghai maglev train, which reaches 430km/h. It flies a very small distance above the track.

It is necessary to have a highly conductive metal track, so the magnetic field is able to induce very high currents, providing enough force to lift the train away from the track. The force exerted by this near-field magnetic repulsion drops off as something like distance cubed (or more, depending on the magnetic field geometry).

Aluminium has an electrical resistivity of 28.2 nΩ·m. Seawater has a resistivity of 0.2 Ω·m, or a difference of about 107. So seawater would make a very poor guideway or landing pad for a magnetic levitation vehicle. The magnetic field required to support such a vehicle would disrupt compasses over a very wide area.

On the other hand, a downdraft of air can provide enough lift to support quite a large vehicle to great altitudes. If this vehicle approached the sea, it would create a bowl-shaped depression well before the vehicle reached sea level.

So maybe the mysterious vehicle was a helicopter or a drone?

#### The Naked Scientists Forum

##### Re: Is magnetic flight possible?
« Reply #2 on: 08/02/2015 20:12:41 »