Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: yor_on on 22/10/2014 10:25:28

Title: Do you like Levitating Houses?
Post by: yor_on on 22/10/2014 10:25:28
Have a look at http://www.forbes.com/sites/aarontilley/2014/10/21/hendo-hoverboard/

the key seem to be "He explained the technology as having a primary magnetic field, then creating a second magnetic field in the conductive surface."

And the difference between it and a mag lev?

I'm not sure, somewhere I saw it defined as a magnetic field directed downward 'pushing on itself' though?
Any one have an idea what differ its 'Magnetic Field Architecture' from the one used for a maglev train?
Title: Re: Do you like Levitating Houses?
Post by: chiralSPO on 22/10/2014 12:38:33

And the difference between it and a mag lev?

I'm not sure, somewhere I saw it defined as a magnetic field directed downward 'pushing on itself' though?
Any one have an idea what differ its 'Magnetic Field Architecture' from the one used for a maglev train?

It sounds like traditional maglev uses an active track, whereas this technology uses a passive conductive surface. Also appears to have one additional degree of freedom than trains (2 vs 1 dimension movement). At 40 watts per kg, levitating a house could get pretty expensive, but I think it could have real potential levitating smaller things for now.

I wonder if an aluminum surface would be conductive enough? Aluminum is almost as good a conductor (2.82×10−8Ω/m vs copper's 1.68×10−8Ω/m), and at less than 1/3 the cost of copper (today is 0.89$/lb vs 3.00$/lb), which increases by another factor of 3.3 when density is considered (2.7g/cm3 vs 8.933g/cm3) so one could get 10 times more surface area per buck.
Title: Re: Do you like Levitating Houses?
Post by: yor_on on 22/10/2014 18:49:02
Seems there are two types of maglev's. Wonder if this idea doesn't use electrodynamic suspension?
http://ninpope-physics.comuv.com/maglev/howitworks.php

If it doesn't then those magnets used should be worth a fortune, shouldn't they? And very special, as they both create a primary, then secondary, magnetic field, spread in a 'plane' (the passive conductive ground it balance on).
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What doesn't make sense is the question of how it uses superconductivity, if so? There is no existing superconductivity at room temperature, that I've heard of? Meta materials?

Don't mean that you need 'coils' placed in the floor, but you should need something inducing the change?
Or maybe not?

Maybe it's electromagnetic suspension?
Title: Re: Do you like Levitating Houses?
Post by: yor_on on 22/10/2014 19:41:32
Or no superconductivity at all? "The rare-earth magnets currently available at the retail level are made of neodymium iron boron (NdFeB). Only three elements are ferromagnetic at room temperature; these are iron, cobalt and nickel. Virtually all other elements increase permanence (coercivity), but any magnet must contain one of the base three to work. The four main magnet types used today are ceramic, alnico, neodymium, and samarium cobalt." http://www.leevalley.com/en/hardware/page.aspx?p=40077&cat=3,42363

And then we apparently have Single-molecule magnets (SMMs) and single-chain magnets. (SCMs) (https://en.wikipedia.org/wiki/Magnet#Single-molecule_magnets_.28SMMs.29_and_single-chain_magnets_.28SCMs.29) I'm getting curious to what it is here.
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spelling, spelling, spelling, as always.
Some fine day I will find out how to spell, just not now.
Title: Re: Do you like Levitating Houses?
Post by: yor_on on 22/10/2014 23:17:24
Ok, maybe it's simpler than I thought. You have Lenz’s Law


Current induced by a changing magnetic field always produces a magnetic field that apposes the change. (i.e. the induced magnetic field pushes back against the changing magnetic field) a opposing force is created.

That's also how you levitate a frog. You create a magnetic field around 16 Tesla, strong enough to create a opposite 'dimagnetic' field inside the frogs body. it's the electron 'spin' inside molecules that produce this 'opposite force', as long as there is a odd number of electrons creating the 'net spin' of the molecule.

So we need a strong magnet, but I don't know how strong?

"The hover tech inside the development kit is able to carry around 40 pounds. The battery inside the device work at an efficiency of about 40 watts per kilogram. For comparison, a helicopter elevation efficiency is about 160 watts per kilogram."

Also seems as the rare earth magnets made doesn't really create the field they are stated too? It's the magnetic flux density that define the field, and if that is 1.5 Tesla someone wrote that "As the owner of many such magnets, the highest flux density I have seen from one is 1300 Gauss which is 0.13 tesla at the surface of the magnet. Using theory a magnet with remenant (residual) magnetic flux density of 1.48 Tesla of those dimensions should give a magnetic field of 0.4 tesla at the absolute maximum."

Still, lenz law explains  "He explained the technology as having a primary magnetic field, then creating a second magnetic field in the conductive surface." which makes me wonder? He could just have referred to the law.