Levitating Magnets: Newsletter Challenge (12/12/06)

and a problem with cold feet when getting out of bed in the morning?

She is,

Levitron hovers without the support of cyrogenic cooling.

She is, Cryogenic cooling was not a part of the exclusion. Magnets can hover above and below superconductors which although are not magnets, they can be used in conjuction with them. Very interesting results can be obtained with helium cooled lead wire coils and magnets!!

Just a thought to the mechanics of the challenge; if the two magnets were thin and flat, wider than the magnetic field is strong, gravity itself would stabilize the floating magnet would it not? Or would the magnet simply tilt and stick on one side the other being too heavy to completely flip over? Perhaps the person who suggested the counterweight has the right idea.

Sam

Some folks seem to forget the concept that the fields decrease/increase in an inverse square relationship with distance. Try one magnet in a plastic "boat" floating over an anchored magnet in a bowl. Or below a plastic or glass bowl. The nature of the field cannot be stabilized with counterweights any more than the magnets themselves can be, as there is a truely sub-micon spot approaching stability. The secret of the bismuth levitation is the Warping of the field between the anti-pole pieces of bismuth, causing a convergence into a virtual magnet in the center of the field. Any movement out of the center is into a weakening field, causing the magnet to recenter into the strongest field (center of the reshaped field.

I think there are potentials for the diamagnetic properties of bismuth and/or graphite that go unassessed because so few people understand or care about the exception to the rules they have to learn.

An example, an insulated copper wire shielded with bismuth. Greater or lesser resistance by confining the magnetic field? Temperature effect of field confinement? A circuit pair, Same questions.

Any answers on something that might have some uses?

RichH

It's just an observation, but I have noted that a strong magnet will attract a weak magnet regardless of the polarity of the weak magnet, though at a distance there is a slight repulsion. Does anybody know what this effect is called?

A further observation, some steels make excellent pole pieces for magnets, has anybody ever seen a pair of magnetically repelling gears? perhaps made from steel with a concentric ring magnet insert in each gear. They could even be suspended on magnetic cup/cone bearings utilising the other two poles of the ring magnets, for extra low friction.

That's a nice thought; the simplest implementations would result in a primarily radial force, whereas the useful part of the repulsion would be the component along the drive direction. Could be worth a bit of conceptual development, if we can find suitably robust magnets?

I have been looking at Wikipedia's comprehensive information on gears, with some rather neat animations. One point that occurred to me was the 'contact roll' designed into gears. There is some rather nice juicy geometry to flex the old grey matter there, but if there is 'no contact' and a repulsive force is at work, a whole new set of parameters enter into the arena. I purchased two five pound 'Lb' Pen Style Magnetic Pick-Up Tools, very cheap at a discount store. You certainly need to flex your muscles to make the two 10 mm diameter 5 mm length disc magnets touch one another. They look robust enough for a steel gear insert. In my minds eye, I can envision high ratio gearing making the most advantage of negligible friction.

You'll probably need to build the remainder of the gear from non-metallic material to see much advantage in terms of losses, but I have to admit that it sounds reasonable (albeit scary) on the face of it. You might try cooking-and-vibrating one of these magnets first, to be certain it will handle the environment of the gearbox.

Thankfully I have data sheets to hand on just about every conceivable magnet. and suitable magnetic pole piece material. I would imagine that eddy current losses due to stray magnetic flux, might be problematical. Envisaged is cup/cone style magnetic bearings, so no surface contact whatsoever under designed load, even air friction could be obviated by a partial vacuum in the gear box, if that was considered appropriate. It's a super problem to sort out with a bit of applied mathematics. I think I know where to get a fine high spec neodymium ring magnet or two. Folk are always blowing their Hi Fi loudspeaker tweeters, that end up in the skip of the local repair shop. Two of those, coupled to four bevel gears, matched like pole-to-like-pole should provide a test bed setup. I might go into my Windows Paintbox to make a drawing, now that I have figured out how to post pictures. (Our Firm has the 'Invent' software, all £4,500 worth, but that won't run on my laptop. It needs a souped up graphics card and memory from hell, as they say.) Ultra low friction should mean low heat. the gearbox should run cool as the proverbial cucumber. There would clearly be constraints on how much power/torque a given gear could handle.

I like the idea of non-metallic components. Some glass/carbon fibre reinforced epoxy resins/plastics etc, outperform steels by a wide margin. but not for heat. Bespoke sintered neodymium magnetic teeth just bu themselves could be an answer. They make them any size or shape you like.......This as an old friend used to say is a 'two pipe' problem, and fill up the big meerschaum bonfire too.

Thank you Physicist for the welcome stimulation and encouragement. I appreciate it.

I know it's not technically possible at the moment but what if one gear was magnetic material and the other a superconductor? That way the magnetic filed would always be repulsive regardless of polarity.

With Christmas just past and fond memories of push-along flywheel cars in my stocking, way back when. I was thinking of a possible flywheel solution to energy storage, An intermediate technology solution to uninterpretable power supply. NASA I note have a great project underway.

Check out:-

http://space-power.grc.nasa.gov/ppo/projects/flywheel/papers/NASA_Flywheel_Battery_Project_Final.pdf

Why not explore superconductors? Epoxy resin is ultra strong at low temperatures. Thin film deposits in a cryogenic gearbox, I was looking at the workings of a software animation of an automobile differential gearbox. I think I will first need to slip my brain into gear before committing a huge gaff but there looks like a generator could be provided with a nice steady drive, from a multi-flywheel battery setup. They say the trouble with wind power, is that there may be most of it when least needed. the enemy of flywheel storage is friction. At very high revs air alone is sufficient friction to contend with.

Hi masu, yesterday was 'Orthodox Christmas' and I received a 'Brain-Wave' of the wacky impossible kind in my stocking. It must have come from Deacon George, or Father Radomir Kostich of The Serbian Orthodox Church.....(explanation later).....

Why?....I thought....Do you need cogs at all?.....'A cog-less gear wheel' should be perfectly possible. As long as 'North' meshes with 'South', I can en-visualise a pair of 'Chequered' magnetic wheels inter-meshing beautifully (but never touching, magnetic cup-cone bearings on the two cog? spindles as well). With these ultra strong neodymium magnets about, that might not be too much of a problem making a demonstration model. I will need to contact my chum who scraps old computers, as those Hard Drive magnets might just be what we need.

That's the 'Possible' experiment,........The 'Impossible' experiment is a mind blower! . 'CRAZY' ....'IT WOULD NEVER WORK'....'IT BREAKS ALL THE LAWS'.....ETC!

So CR4 readers, While I draft this 'GIZMO' up in Windows Paint Shop, I think I know why it won't work, but it's too tempting to ignore. I will need to draft it up in Windows Paintshop, to reveal the workings. I will post that later. It could be the start of a 'Wacky CR4 Thread' ...After all, there is no harm exercising the old grey matter, understanding why something won't work is knowledge worth gaining.

Can't see any reason why it should not work provided the the secondary gear had a fair amount of flywheel effect.

I think your cup bearings would have to be pretty robust and I can see plenty of eddy currents all over the place.

Best of luck!

He He!.....We will deal with the 'Eddy Currents' later syphrum,.....It is blooming slow work drafting in Windows Paintbox, but I hope the result is worth the effort. Thanks for wishing me luck.

When our friend 'MASU' sees it, I suspect he will know where the inspiration came from.......He He!......I stink I need a can of beer to steady my hand. This drawing is in colour. Perhaps later we can 'Animate' it in a 'Java' script program? So far it's looking good. Masu might even like it for his 'Icon' perhaps without the bloodshot eyes? This is I believe the 'ACME' of 'PERPETUAL MOTION MACHINES'

Everything works in animation. There are some interesting ones on Google Video, but this I hope will knock spots off the competition.

Hi Alistair, I love the drawing. I'm glad I can inspire even if is because of my funny looks.

Since you are using paintbox to do the drawings I thought you might appreciate a package called DeltaCAD . It's a 2D drafting package that I use for all the drawings I post at CR4 as well as for circuit diagrams, PCB design, mechanical drawings and just about anything else you would use a drafting board for. One big advantage is the drawings are to scale so when you have finished you can measure the final result and using the dimension tools add all the measurements. Best of all it only costs US$40 and has a fairly good tutorial that walks you through most of its features. You have obviously has some sort of technical drawing training so it shouldn't take you more than an hour to learn how to dive it. It's a pretty stable product and I have been using it for well over a decade and have never had a serious problem with it.

Your idea of the magnetic gears had me thinking and is suddenly dawned on me that a stepper motor is pretty much a magnetic gear. The only difference is that instead of meshing with another physical magnetic gear the rotor meshes with an electrically generated gear. It might be interesting to pull a couple of old motors apart and play with the rotors.

Hi Masu, Thanks for the tips. The stepper motor observation, is I think a good one. Here is a rough sketch of an another levitating 'magnetic gear' concept. Two ring magnets from a scrap pair of old loudspeakers, might prove the concept. They also would come with suitable pole pieces. Drill out the centre, and mount on two suitable bearings. Have both magnets in opposition and just touching at the two steel disk pole piece edges.....Then carefully grind/file away the 'wavy' edge as illustrated above. I am sure they would mesh by magnetic levitation. The flux increases to the inverse square of the distance separating the two poles,(approximately) so as two hump peaks met, the would soon get into step.

Might make for an adjustable torque drive? I also wonder how it would mesh with a much smaller wavy gear, perhaps with only a very few 'waves' just three even? As the gears never even touch, it might make reasonable drive for a high speed 'centrifuge' ..or perhaps a way of extracting power from a flywheel battery? As this is just flights of fancy, how about a 'levitating magnetic' chain/belt drive? with a tensioner to adjust torque output?

Hi Alastair

I don't imagine that the following is what you mean in this posting, but..

Conical gear-shaft pairs with magnetic 'cogs' might make a nice clutch-less gear system. Might be robust too - though you'd get a lot of vibration if the gears did start to slip. I wonder if it would be possible to arrange embedded conductors so that the eddy current damps rotational slippage but does not cause significant loss due to the 'usual' directions of relative motion?

Fyz

Hy Fyz,

The draft plan of my 'Heroic Failure' is about half done. I hope to post it up soon, The gears may not suffer eddy currents if the 'box' is made from reinforced plastic or ceramic. I hope you all have a chuckle at the 'Perpetual Motion' concept.

BTW. Fyz, I have wasted many an hour, even weeks trying to conquer the magnetic perpetual mobile paradox, never expecting more than a minute fraction of over-unity. As an Applied Mathematician by avocation, there seemed to be a few loopholes, but alas failure haunts me to this day......

The upside, is that the 'spin-off' from trying to do the impossible, is almost always very fruitful. The next 'Windows Paint-shop' contribution to CR4 will be I hope quite a mind-blower and relates directly to the 'Masu' perpetual motion machine. Note the inclusion of the 'Transformer Steel' inserts at the joint of the two circles. This is the key. Dear 'Stirling Stan' from CR4 has sent me loads of Data on Sterling Engines. I would like to make an 'Internal Combustion/Stirling Engine Hybrid'

The purpose is to vibrate a multi-layered 'N-S-N-S-N-S' magnet up and down in a cavity between several of those 'Masu' type motors. If the polarity is constantly alternated, then it becomes effectively a 'Stepper Motor'

The simplest 'Internal Combustion Engine' is a four-stroke vibrating corrugated spring disc. There are no valves to bother about. just a spark is needed to ignite the Fuel/Air mix at the right moment.

The 'Spring Disc' also acts as a 'Bellows' & 'Reed Valve'........ First there is a 'Corrugated Dish Cavity' bellow the spring bellows, that naturally is the same profile as the 'Corrugated Spring Bellows' .....(when extended).....This bellows has a natural resonant frequency.

(1) A Gas/Air mix inside the combustion chamber is ignited with a spark. hence the circular disc bellows expands upwards, also driving the magnet up.

(2) At full extension the exhaust openings are opened by the 'Reed Valve' effect.

(3) When the exhaust combustion products have vented..... (To the Stirling Engine).....The corrugated spring disc bellows collapses. emptying the chamber.

(4) Next the stored energy in the spring, ...'bounces back up'...drawing a fresh mixture of Fuel/Air into the combustion chamber.

(5) This in turn.....'bounces back down' compressing the Fuel/Air mix. (reed valves closed by the gas pressure)

(6) "BANG!". ..... The cycle repeats

The secret of success is all in the reed valving. which needs careful design. Cross-Flow heat exchange and Stirling Engine Heat Regeneration, will be crucial elements of the final design. The next draft, much like the 'Masu' concept, will only be a 'Schematic Illustration'..... Time to get busy again with 'Paint-shop' Cheers, and many thanks for all the feedback.

Postscript:- I have been fascinated by those 'Shake Torches' ....magnetic suspension and circular spring bellows? .....If the entire 'Engine' just vibrated up and down....

Even a 'Two Stroke' engine might work. The power stroke, also the compression stroke at the other end of the cylinder?..... with a magnetically suspended cylinder/piston affair. One can have as many corrugated disc springs as needed for the inlet & exhaust, i.e. air tight . Just seat the magnet on the engine and give it a 'bumpy ride'

Small is beautiful.

Double Postscript:-

We are talking 'Magnetic Levitation' on this thread. Also we have introduced the concept of 'Flywheel Batteries' ....magnetic levitation in cup/cone bearings.

An old concept is a 'Bladeless Fan' also used as a pump, that ban pump live fish without injury...cool...

So 'SCRAP' compression strokes, as we have a ready compressor; driven by our 'Flywheel' .....The compressed air will also heat, so that extra heat can help the Stirling Engine end of the business, along with the exhaust heat. After heat exchange, the cold compressed air can also provide a bit of refrigeration for the Stirling Heat Engine. Bernoulli will see to the Fuel intake. Propane would make a good fuel.

Goodness a 'ONE STROKE' combustion engine/generator. (Shake Torch?)

Wankel managed zero stroke - Great power density, shame about the efficiency

Indeed Fyz, great power density, but I believe the constant problem was wear on what a normal engine is the piston rings. I once read of a multi-chamber Wankel Engine intended for one of our Tanks. The cunning brute had a plough-shear mounted underneath, that dug up the road, and the bitumen was evaporated as fuel for the engine......spewed gravel out the back end. The military are often wicked I should know.

Isn't this a "challenge(r) myth" (both military and CR4 equivalent of an "urban myth")

Fyz

Hi Alastair

Perpetual motion: 'in my youth' I tried to "imagine three impossible things before breakfast". Alas, I lacked the gift, so the result was I went straight on to lunch... Maybe I'll be more successful now I am into my second childhood.

Regarding Stirling engines - great Scottish design unjustifiably neglected by the world. Historically, it seems to have been limited to similar efficiencies to the internal combustion engine, but modern materials and/or modeling might change that. Enjoy

Fyz

That's why those UFO's spin

Are the crew quarters de-spun or do they like the extra gravity

That's why those little green men have evolved two antenna on top of their heads,

Check out:- http://en.wikipedia.org/wiki/Coriolis_force

After living and evolving for ages in outer space, I guess they need those antenna to stop from getting flying saucer space sick.

There's been a lot of interesting discussion about various ways to do this. The intended answer (I wrote the original question) was to use a spin stablized magnet. There's a "toy" device called the Levitron that does this, as shown below:

It's very cool. Mine will levitate for about five minutes until the top rotation slows enough that the system becomes unstable. You can actually buy a device that goes under the base that's essentially a stator winding and keeps enough electromagnetic torque on the rotor to keep it spinning indefinitely. Caltech has had one levitated in a lobby display case for up to 314 days at a time. The principles that it works on are more complicated than just having a rotational moment that overcomes the tipping force - if you're really into the math you can check out the references in my post #36

The toy really is a lot of fun BTW.

Steve

I have almost the same setup as CalTech. I have a transparent cover over the top to prevent any stray wind currents from disturbing the top. The copper disk is what really helps. It's been spinning since Dec 22! I first started it on Dec 15, but when the blizzard hit in CO, I think the power went out for a few minutes and caused the top to fall. If it falls again, I am going to get a UPS to help if the power goes out again.

Yes, it is a lot of fun.

--Ariel

I like challenges like this. I was thinking of applying magnets to a non-metallic concave dish, all polarized in the same direction. Then coat a small ball with magnets that all repel the magnets in the dish. This idea is based on a study I was involved with before spaceflight began. We were interested in seeing if we could reproduce the effective conditions of an absence of gravity on mineral samples that would not fuse in a gravity environment. This was accomplished by producing a conical shaped RF coil. Metals that were placed in the center of the field levitated as a result of the eddy currents that were induced into the samples by the RF. These samples were heated with a torch if not by induction and a variety of odd lot samples evolved that were analyzed for unusual properties. None of the results looked anything like what we got back from space years later. Gravity and eddy currents are not the same. But with careful control of the dish magnets success may be possible. But Earnshaw's theorem may hold up if cleverly stated.

"Then coat a small ball with magnets that all repel the magnets in the dish."

This is of course a heroic attempt to produce a pseudo monopole but I am pretty certain that it would not work, if you have all outward facing North poles there must be a route back for the lines of force to the central south poles.

In any event, Earnshaw applies to monopoles as well (including gravity and electrostatics). Neutrality and/or stability is/are only possible when the poles are in some sense moving - e.g. reflection in a superconductor, diamagnetics.

Fyz

"Neutrality and/or stability is/are only possible when the poles are in some sense moving - e.g. reflection in a superconductor, diamagnetics."

The diamagnetic levitation of a magnet is not a dynamic. It is a purely static, non-energy dependent room temperature result of the "lensing" of force lines. In the example of the bismuth lenses, the cavity between the diamagnetics is forcing the lines around the anti magnetic pieces, resulting in the circular perimeter redirecting the lines of force back together in the center of the cavity. The highest density then results in the center of the cavity, causing the levitated magnet to seek the virtual pole piece centered laterally and vertically between the diamagnetic "lenses"

Acting as a virtual pole piece, the Earnshaw principle is then preserved by means of the levitating magnet being attached to the artificial, virtual pole, without "moving", without the addition of any power or cryogenic materials. No cords, no batteries, no liquid helium source to deplete. I guess that makes us lucky to live in an environment of -50 to +50 C, or we'd have only graphite to play with.

RichH

The diamagnet is static/dynamic in the same senses as the superconductor. The 'dynamics' I am referring to is the change in magnetic moment of the diamagnet when there is relative movement between the diamagnet and the permanent magnet. This is what is needed to break the inverse square relationships. Sorry if this was ambiguous.

What relative movement? There is no movement, no angular velocity, no spinning. No worry about power going out. Seal it up in a glass globe and it will stay aloft longer than any newborn would live f born today. Freeze it, warm it up to 200 C, (I think the bismuth melts about 243 C), place it in a vacuum, pressurize it to 20 bar, without the application of some external mechanical, gravitational, or emf force to remove the magnet from the virtual pole, it cannot want to tip, slide, or flop away from the virtual pole. It would be very interesting to view the fields involved, especially before inserting the levitating magnet.

As far as the gravity free metals, since they are not "soluble", are they basically a colloidal suspension, and if so, what happens when one materal starts to solidify before the other, presumably the matrix first? Will there be any actual "wetting" of the matrix by the colloidal particles/drops? Isnn't there still a tendency for the colloidal material to accumulate from the brownian collisions while liquified? If the colloid were the higher melting material, would it's surface be wet by the matrixmaterial? If the materials are not wetting, is there any interaction of the materials, or does one merely become the filler within tje matrix? Can the melt be "ground" to a near molecular suspension and solidified prior to the aggregation by wetting of the materials? I would think that slow cooling would result in a crystallographic seperation of the materials. Could soluble metals (alloys) be seperated chrystallographicly by slow cooling? electrophoreticly? chromatographicly?

Totally unrelated, but I suffer ADHD and my mind multi-tasks. I tend to solve problems other than the one started with my whole life. That bugs some people.

We all suffer from something. I suffer from impatience and an idealised view of what is possible from human behaviour. Theoretically, knowing that I suffer from the first should condition me not to suffer from the second - nevertheless, that's how it is.

Now, back to your "no movement": obviously, I did not express myself sufficiently clearly, so please bear with me right through the following, and read it through again if it doesn't figure the first times:

There is always movement* - thermal vibrations, gravity, even (in an ideal environment) Heisenberg...

What I am writing about is the way the diamagnet responds to such movements (however slight). Now, I'm going to be a little bit lax in my terminology, because I think the result will be clearer: unlike a permanent magnet, the internal counter-magnets in a diamagnetic object move relative to the object itself. And, unlike a ferromagnetic material, they move in such a way as to counter the motion. It is this response of the passive internal structure that enables the diamagnet to maintain a stable position.

Unfortunately, if that is not sufficient explanation, there's no alternative but to go away and do the sums.

Fyz

*If there could be "no movement", it would be possible to leave an ordinary stationary magnet suspended for ever - even though the equilibrium is unstable.

I have been watching the discussion regarding the properties of the bismuth in the system posted earlier. NoSciFi you stated in an earlier post

"The secret of the bismuth levitation is the Warping of the field between the anti-pole pieces of bismuth, causing a convergence into a virtual magnet in the center of the field. Any movement out of the center is into a weakening field, causing the magnet to recenter into the strongest field (center of the reshaped field."

which seems to indicate that you have a misunderstanding of what the properties of a diamagnetic material are.

Materials are grouped into one of two groups, magnetic or diamagnetic.

A magnetic material will be attracted to a magnetic field regardless of its polarity. For example a lump of iron will be attracted to a magnet along the lines of magnetic flux towards the pole regardless of which pole .

A diamagnetic material acts in exactly the opposite way, which means it will always be repelled from a magnet along the lines of magnetic flux regardless of the polarity. An example would be that in a zero gravity environment it you moved a magnet towards a lump of bismuth it would repel the bismuth regardless of the polarity of the magnet.

The problem is that the diamagnetic force is miniscule when compared to the magnetic force. The reason the system described earlier is that the weight of the magnet inside the bismuth cage is effectively cancelled by the large magnet that is above the cage. The effectively leaves the repulsive diamagnetic force that is generated by the bismuth cage to effective hold the magnet in the center of the cage.

This is a simplified description of the device but the important thing is that it is the repulsive diamagnetic force that is being used to stabilize the levitating magnet.

The repulsion of the bismuth by the magnet (ic lines of force) is a mutual repulsion. The lines of force are warped by the diamagnet and though not totally prevented from passing through, are warped away, opposite of the concentration that occurs with a ferrite material. Where it only the repulsion of the bismuth and the suspension by the exterior magnets at work, it would not have the self-centering effect that stabilizes it. Else Earnhart would apply and the tendency fo flip or move would outweigh the diamagnet force, drawing the levitated magnet out from the center. And as I recall, there is no need to have the levitated magnet's polarity in a specific alignment for it to work. I no longer have it, having passed it on to a high-schooler years ago, but yes, you are right about the diamagnetic effect being insufficient to raise the floater, so the suspensive force of the externals is needed, but if those were the only effects at work, Earnhart would win, wouldn't he?

RichH

Have you ever seen the levitating frog video.

http://www.youtube.com/watch?v=A1vyB-O5i6E

It demonstrates the diamagnetic properties of the water in the frog by sticking it in the middle of a really humungusly enormous electro magnet and switching it on. It evidently has no ill effects on the frog.

I'll have to make a bismuth tube maybe 3", use the old iron powder line trick for a magnet without and within the tube, tu see if the lines ccan be confined within the tube, as though the magnet were 3" longer. It'll take me a couple of days to set up, but I'll post pictures of the results. Bismuth is hard to cast. It share the property of water of expanding during the phase change, similar to ice forming. That generally causes pressure to distort a mold, or break a rigid mold. Maybe I can also use paper horizontally and cross-sectionally (seperate set-ups) to view the field effects of the bismuth lenses/ I still have some shot left, maybe enough for the pair of slugs needed. It might even be fun.

Matter of fact, I have a pair of ≈50 gram pieces. I think I can find them.

Thanks for the educational idea. Damn I wish I still had a lab available.

The frog is cute, but the field strength is far beyond any magnetis material known to date.

RichH

NoSciFi you wrote:- "Bismuth is hard to cast. It share the property of water of expanding during the phase change, similar to ice forming."

What is of interest in this comment, is that I believe Thomas Seebeck was casting a large ring of two metals in his laboratory. The substantial circular mould was divided with two partitions, Thomas we think was intending to progressively melt the Stibium (Sb for Antimony Thermal emf versus Platinum cold junction zero, hot junction 100 C = +4.89 mV, Resistivity 39 micro-ohms/cm) and Bismuth (Thermal emf respectively -7.34 mV & Resistivity 106.8 micro-ohms/cm) thereby examining the properties of various percentage proportion alloys of SbBi,

When the two component alloys had cooled, Thomas Seebeck embarked upon melting one of the junctions of this gigantic? ring of bi-metal, ....Do the sums, .....This is a closed loop single turn solenoid, and as poor Thomas started to re-heat one junction of this thermocouple, the thermoelectric emf increased. Never mind the low voltage, the Ohmic resistance was also very low.

Result, every iron and steel object in Thomas Seebeck's Laboratory 'STOOD TO A SMART ATTENTION' on the bench. perhaps many thousands of amps were flowing through this closed circuit solenoid?

Thomas Seebeck shouted... (we can imagine)... "EUREKA I have discovered the source of magetism" ....... So he thought, Peltier was later to correct him.

The only comment I can add is that the resistivity of the bismuth increases dramaticly (I didn't reference how much. the field strength would need to be guessed.) when such a strong field is applied. I wonder how much heat was generated in the bismuth half from the resistance?

RichH

This was way back in 1821, I would love to know the actual details of Thomas Seebeck's experiment, as I can only guess at what he was up to. Indeed you are correct about Bismuth's increased resistivity, but with about let us guess 20mV thermal emf, Bi melts at 271.3 C, (Sb at 630.7C) with the possible resistance of the circuit in mico-ohms, there could have been a belting high current. Not much heat from the resistance, as the wattage would be relatively very low. I am only guessing, but Thomas Seebeck may have been attempting to establish the 'Eutectic Point' of the SbBi alloy? I would imagine the thermoelectric effect came as quite a surprise.

It might be rather fun to reproduce his experiment in costume drama, for a TV education programme?

Bismuth has several strange properties. Is there a list of compatible metals, or is it just a member of the cupric metals, or more alumina group? I should know from the periodic table, but it has been toooo many years since I even looked at a table much less thought about the relationships. I'm guessing that it would be pretty close to matching lead for most properties. And are there any differences between Bi and Pb? Inquiring minds want to know. Now if I could remember where that line came from.....

RichH

'Hopper' crystals of Bismuth are rather fun to make (caution health & safety) This illustration from Wikipedia is an example.

For the Periodic Table, Type 'Tom Lehrer Elements' into You-Tube and see what crops up. Though not nearly as toxic as Arsenic it falls into that group, with Stibium or Antimony 'Sb' in the periodic table. Lead is a primary 'mother' ore of Bismuth, so is Tungsten. One thing I noted, was that China is a major source, and also 'Borat' land. Kazakhstan. Now that you see relatively cheap drinks coolers with Bismuth Telluride Peltier heat pumps, remember those also work backwards as Seebeck generators. A Professor of Electrical Engineering from Cardiff University (not been in touch 4 ages) has this neat system, when he gets in his bath, he powers up his computer with a BiTe Seebeck system plumbed in. When he gets out, the power circulates the hot water by heat exchange back into the hot water tank, ...cool or what?

I think you would find that bismuth is nearly non-toxic, the very least of the heavy metals. People have been known to ingest as much as a pound of bismuth over a period of several years without ill effect. They can even sell the pink oxide emulsion in food and drug stores. That is the main ingredient of Pepto-Bismol. I don't have any at home, but I seem to recall that it is 5 or 6 % bismuth oxide. Or maybe bismuth as oxide. However, I think I do recall that injection of bismuth can be toxic.

Like I said, a very strange set of properties.

RichH

You may find this periodic table of the elements interesting.

http://www.popsci.com/popsci/periodictable/

You may be right syhprum, but I just happen to have a big box containing enough magnets to cover about a hundred soccer balls + dishes to match. They are only ferrite, "but the proof of the pudding" is always experiment. I will post the answer, with a suitable photograph.....When I find a soccer ball. The kids won't miss it.

Well 'MASU' Those 'Cross Eyes' gave me the Inspiration....OK.....So it won't work, BUT IS IT ART? or perhaps me may have struck lucky?........"MARK TWO" is already in the pipeline. That probably won't work either!

I think what you need to do is produce it as a twenty pole magnet, single poles, not top/bottom per your drawing. Then you would drag opposite and push similar poles, say 20 1" poles on one, and 6 1" on the other to produce reduction as needed. Pole length would be equivilant to the pitch of a cog gear. High speed might generate some heat, though.

Nice drawing, but I think the nitrogen bubbles got to you.

RichH

?Thanks for the input 'NoSciFi', much appreciated. Quote:- "I think the nitrogen bubbles got to you."....Circa 1980, I was in Kenya and got a dose of Cerebral Malaria complicated with Heat Stroke. The Doctors actually sent me to the morgue. I don't think I have any 'brain' left for nitrogen bubbles to bother with.

The cunning plan here is to devise a "Magnetically Suspended Flywheel/Diaphragm Vibrating Stirling Generator/Motor" They used those diaphragm Stirling Generators on Marine Buoys. The Phillips Corporation actually managed to coax 78% Carnot Efficiency from them, but in service the temperature was reduced somewhat, to achieve a still commendable over 50% + efficiency. Still a lot better than any internal combustion engine.

Essentially the Stirling Generator was just a corrugated disc bellows. The discs also incorporated heat-regeneration, and the system worked on an inert high pressure gas........... "Nothing like reinventing the wheel."

Flywheel storage of energy is still streets ahead of chemical batteries, and Hydrogen storage is still bulky for fuel cell applications. Now that small motors are well over 90% efficient, those efficiencies used to be the province of very large electric motors. Automotive manufacturers are dedicating vast research funds to electric traction.....blah blah.....Racing Cars used to have inboard 'Disc Brakes' to save 'Unsprung Weight'..... why not inboard 'Electric Brake/Motors/Power-Regenerators'?

Say goodbye to differentials/gearboxes/etc. and have four wheel drive as a bonus. A Multi-Fuel Sterling Electric Generator, that also incorporated a bit of 'Flywheel-Regeneration'.. enough at least to floor the throttle for a minute or two? might be a reasonable dream to pursue. Miniaturise the Stirling Generators Etc. and design the components as an integral part of the automobile structure. We are entering the age of 'Robotic Manufacturing' small is very beautiful for robotics.

"Flywheel storage of energy is still streets ahead of chemical batteries, and Hydrogen storage is still bulky for fuel cell applications."

There is one problem with flywheels and that is the more energy you store in a flywheel the more the gyroscopic effect. If the axis of the gyroscope is mounted horizontally then turning a corner becomes a serious problem, if you mount it vertically then when you try and go up or down a hill you suddenly do a right of left hand turn. Back in the early days of aviation when they used rotary engines it was a serious problem, certain types of aircraft were real death traps. If you tried to turn one way you would bury the nose in the ground, turn the other way and the nose would pitch up violently, stall the wing with the result of burying the aircraft in the ground. Trying to climb and descend wasn't quiet as hairy but it did result in unanticipated changes in the direction of travel.

The only solution is to mount the flywheel on gimbals but this can be difficult and adds to the overall weight and complexity of the system.

Hi Masu

Gimbals are not the only solution - opposing flywheels would work perfectly well, but the bearings would need to cope with rather large moments.

Fyz

This is true but dose having counter rotating masses counter the effect of the gyroscopes wanting to point in the same direction all the time.

Several 4 engine aircraft used normal clockwise rotating engines and props on the right wing and counter-clockwise on the left to avert the problem. Too expensive to maintain, more parts that were easily confused.

Lets say a large 4360 would have had a ton of prop, 1500 rpm, 4 foot mean radius, plus 500 lbs of crank at 2000 rpm and mean radius of 5 inches. I don't think that would be much worse than a similar tuboprop, same prop speed, and a rotor of about 800 lbs mean radius of say 10", and an rpm of 100,000 rpm. They still make a lot of tuboprops ,some with counter-rotating props on the same engine resulting in the elimination of the prop angular momentum and gyroscopic effect, plus smaller props. I think that's a Russtan design.

Moving 2 or 3 jets to the rear near or in the empanage (tail) would only add to the problem with say 3 rotors (engines), 900 lbs each, at 100,000 rpm and mean radius of a1 foot, and 50 feet behind the center of gravity, the same problem exists for the modern jet.

And the Thunderbolt with a 3300 and a 19 ft prop had a greater risk of flipping on takeoff from the excessive torque than the gyroscopic effect. And I still like the sound of a 800 or 900 ci radial over all the newer planes. Kindof a Harley effect.

RichH

Hi No_Sci_Fi, I have a query;

"I don't think that would be much worse than a similar tuboprop, same prop speed, and a rotor of about 800 lbs mean radius of say 10", and an rpm of 100,000 rpm."

Where did you get the 100,000 RPM figure from?

The highest speed turboprop engine that I could find was the Rolls Royce 250-B17F that has the high-speed turbine flat out at 50,000 RPM but it only has a diameter of about 150mm and is mostly titanium.

As for fan jets the Rolls Royce RB211 engines that are used for numerous ground and ship-based applications as well as aircraft like the B747-400 the rotational speeds are even less. The figures for 100% rotational speed are Low Pressure 3,900 RPM, Medium Pressure 9,100 RPM and High Pressure 13,300 RPM. These are the absolute maximum speeds and can damage the engine, take of is around 95% of this and can only be used for a maximum of 5 minutes while the normal operating speeds are around 75% of this. The other thing is that the higher the speed the smaller the diameter and by the time you get to the HP stage it's something like 450mm in diameter and its nearly all titanium.

Put all this together and the gyroscopic effect is a lot less than you would expect.

One of the most common demonstrations of gyroscopic force we see in daily affairs is in motorcycling. When I rode lightweight bikes, I could lean by man-handling the machine with my body weight. Now, on a heavier machine, I find that man-handling does not work so well, but the tiniest cocking of the handlebars will be met with a precessional reaction and the bike will lean: I mean, substantially and rapidly, post-haste, toute suite, etc. A word of caution, the effect is counterintuitive. You cock the front wheel ever-so-slightly left to lean right and turn right.

The OLD GE J79 was rated for 16,700 rpm take-off, and max dia was 17.5 ". A P&W 2003 would have an exhaust rotor diameter of roughly 1 M, or 18" radius. You're right, it's a much lower rpm. Too many years since I worked on the recips, and jets were an auxiliary engine attached. At that time, Solar was making the small aux power units (APU's), and I believe that some of those units were 100K rpm. Currently, 60,000 appears to be the max APU rpm.

Add in the fan/bypass uniys with their 10 ft diameter, almpst the equivilant of a large prop, with double the rpm and half the weight.

But, you were right to call me on it. Sorry.

RichH

Hi RichH, "Kindof and Harley effect." I have to admit, that one is new to me. A quick search was fruitless. Have you any links you could recommend. I am extremely grateful to everyone here for educating me on so many different aspects of Physics, that sadly I am a bit rusty on. I desperately need the valuable revision. My love of engineering, as a bit of a groupie, is the exemplary 'teamwork' one always encounters. This morning Stirling Stan's CD's on no guesses what, arrived through my letter box. A BIG WARM 'THANK YOU' Stan.

One disadvantage of combustion engines and big heavy props, is the irregular variations of torque through the engine cycle. Occasionally the propeller is turning the aircraft.... not the other way, as it is supposed to be....This I read, places great strains on the airframe. worst of all, they are 'vibrational' in nature, and so potentially very dangerous. Stirling Engines, Gas Turbines and indeed Electric motors do not have this characteristic. I saw a ten ounce 2700 watt 2 x 2 inch cylinder case, electric motor for aero-modellers. "WOW", is all I can say. The drawback is the battery pack needed to power it........ This is the impetus for my wacky Stirling/one-stroke combustion hybrid power pack.... we have an electric ducted fan R/C Model Harrier Jump Jet to Fly here in the UK. It's in 'Moth Balls' till we can provide sufficient power. A worthy challenge.

Take a look here for an engine

http://www.wrenturbines.co.uk/jets.php

Alistair, you were talking about your model Harrier

"This is the impetus for my wacky Stirling/one-stroke combustion hybrid power pack.... we have an electric ducted fan R/C Model Harrier Jump Jet to Fly here in the UK. It's in 'Moth Balls' till we can provide sufficient power. A worthy challenge."

This sounds impressive, have you seen the small gas turbine engines that have started to appear in the model arena of late. I am not talking about the ducted electric fans used in model jet aircraft but rather real scaled down gas turbines. They would definitely be capable of providing the power but I am not sure that anybody has built a high bypass ratio one that could be used in a mode Harrier. As you are probably aware the forward vectored thrust nozzles are supplied by the low pressure compressor while the rear ones are supplied by the exhaust from the turbine so a simple gas turbine wont work, you need one that has a bypass system.

In any case this is going to be one intricate, difficult to control merciless model, the real ones are a really thorny to control when in hover mode. If you ever get it going I suggest you practice with the tethered from all directions including above till you get the hang of it. I think just about everybody at CR4 would be interested to see it flying so pleas video it's first flight so we can see what it looked like before it crashed.

This was the sad demise of a dear old friend's Brother. Wing Commander Larsen on November 28th 1957. Thrust Rig XK426, The second 'Flying Bedstead'. If only he had used a wooden dip-stick and not trusted to a fuel gauge stuck on 'full'.

Ashley Bryant who is organising the R/C Harrier Jump Jet Project, now in moth-balls, needs a 4 Kilowatt power supply. I hope we can deliver? The avionics are not direct, and there are a lot of electronics on board so this bird should do as she is told. You are right to be concerned for safety. The University of Reading have had a large input into this project. £50 K has been spent to date, plus a bit! There may be some important spin-off development technologies here.

I was thinking a metal powder like Aluminium, might be a good fuel for the 'One-Stroke' Boxer tube, internal combustion/sterling gizmo/power plant. Ashley told me that 3.5 Kw. was required as continuous power, but any surplus would be a boon. All this talk of high-rev turbines fits neatly in with flywheel battery storage. Magnetic suspension could be adopted for the valve system. Just a spinning perforated tube. A boxer engine would cut out vibrations, effectively four combustion chambers. with 'counter rotation' as a valuable CR4 suggestion, let's make that a full eight. 'Symmetry' is always beautiful. I think it's time to put four new AA Alkaline Cells in my 1978 Vintage CASIO fx-201P It eats batteries for fun, but is still doing quadratic functions 28 years on. It's a treasure and it always gets the quality work, for old times sake. First calculation is potential watts per unit weight of building material & fuel. i.e a light-weight but strong fast spinning tube....diameter-v-wall-thickness, which is better? this Flywheel is supposed to double as a compressor. Loads of lovely mathematics....whoopee.

I shall ask Ashley to post any video material past present or future on You-Tube or Google Video. and give post a link here on CR4.

Sorry about the tired fingures on the keyboard. The sound of a Harley-Davidson motorcycle is a rather revered rumble rather than a blat or wizz of many other bikes. Kind of a Harley effect. A beautiful feeling sound.

The old WWI era French Gnome aircraft had a stationary crankshaft and the entire radial engine -- crankcase, jugs and all -- rotated and the prop was attached to the crankcase! Aviation historians say that it had strange flight characteristics indeed.

P.S. We already drive magnetic stir bars and pump heads by magnetic coupling to negate otherwise difficult shaft sealing problems.

The gnome was one of the aircraft I was referring to but it was by no means the only one, the British and Germans also had aircraft that used the rotary engines and had similar problems.

Quote:- "The only solution is to mount flywheels on gimbals..." Thanks Masu, you must be a mind reader. I think? it was Lotus Racing Cars who were teaming up with Rover Cars to incorporate a 'Gas Turbine' engine into a racing car. The Rover is a rare collectors item. The gyroscopic action had the advantage of keeping the car on an an even keel round corners....good for 'traction'...but as you said going up and down hills was a bit of a drawback. I think? they did allow a bit of gimbal rotation in the turbine mountings for this. Just think Monte Carlo...all those hills and sharp bends, but a great place to squander all your money and meet Dolly Birds. For aircraft, that after all have some fairly big gyros mounted as Turbo Jet Engines. I can see the drawback, a tight loop-the-loop would put a lot of strain on the airframe.

BTW, I believe that way back in the 17th century the first concept for an internal combustion engine, was intended for an emergency pump at sea. GUNPOWDER was the intended fuel. Check out:- http://www.teamvideo.net/m-motor.html They may even have got a bilge pump working on this principle. no cylinders, just a reinforced barrel with pipes and valves, I pity the sailor who had to work it.

I believe it's possible to create an anti-gravity aircraft based on the Levitron model, albeit modified. In theory you need a series of large rotating magnets to generate the opposing forces and spring-like supports housed in the frame that allow the magnets to interact with each other and to move the lower part of the craft upward. This is cruical to generate the lift. The internal frame would not be magnetised. You also need conventional thrusters generated by gas turbine engines. The craft would be able to levitate without any thrust but only achieve minimum lift. The thrusters (on the underside and right and left of the craft) are required to increase speed and facilitate direction.

Hello and welcome to CR4 Guest, I believe NASA are still investigating the Eugene Podkletnov "Anomalous weight change effect" where it is claimed a 2% reduction of weight has been observed above a spinning superconductor. If confirmed this could impact upon satellite maneuvering and prove very useful. NASA are being very cautious at the moment, possibly waiting till there has been International duplication.

Anti-Gravity, seems to be a bit on the strong side for any claims at the moment, but let's keep our fingers crossed. I am personally all in favour of investigating "out of the box", The old paradigms seem to be slowly eroding away, Extraordinary claims also require extraordinary proof. experiments need to be repeatable. One of the great advantages of the ubiquitous "Conspiracy of Scientific Suppression Theory" is that so many believe it to be true. This may often lead to International research efforts to test the claims, based on the unfounded...(we assume)... speculation that nasty corporate/political lobby groups are suppressing Scientific discoveries. The movie industry tends to reinforce this perception. Movies after all have to have goodies and baddies. you can't sink much lower than selfishly suppressing something of universal benefit to humanity. The audience are bound to hate the villainy.

Returning to reality, I suspect we may have to wait awhile before non-reactive propulsion is a confirmed phenomenon. Not to look for it would be unadventurous and rather mean spirited, all power to their elbows. Thank you for the contribution to the thread Guest.