Floating on Electrons: Hyper-Barge
By: Anthony Repetto
Tags: Science, Electric Vehicles, Transportation, Hyperloop, Engineering

~ forget magnetic levitation — use static electricity for your bullet-train~

Photo by Oliver Frsh on Unsplash

Yeah, the Hyperloop has gotten a lot of talk. And Japan, China, Europe all have bullet trains. Magnetic levitation at Disneyland. But, there’s one wrinkle to the design-puzzle that has gone unexplored: using static electricity to levitate in an evacuated tube. Why does that difference matter? First, if you want to travel as fast as a rocket, you MUST siphon all the air out of the tunnel. Otherwise, air resistance absorbs all your fuel, and it’s just not worth traveling more than a few hundred miles per hour. Then, to travel so incredibly fast, you also can’t be touching anything — levitation is mandatory. So, definitely only going to get a ‘hyperloop’ by levitation in a vacuumed-up tunnel. Why use static charges, though? That just sounds like the magnetic one, but different words…

Electricity vs. Magnetism

Magnetism comes in a few flavors — you have permanent (iron, neodymium,…) magnets, and ‘electromagnets’ that only work when you feed them huge amounts of electricity. I’m not a fan of either of these; the permanent magnets lose their oomph if you push against their natural magnetic direction, while electromagnets are costly energy-hogs. Magnets are a problem for designing a train, because you have the weight of the train’s cargo pointing down into the Earth, and the only way to support that weight is with magnets that you’d hope are pulling the weight up from above it, because a push would de-magnetize them quickly, especially with the shock of the train moving over them. However, by pulling the weight upwards, you engineer yourself into a corner: the magnets get stronger pulling, once they’ve started pulling too far! That requires computer controls, and imposes risks, which is exactly how it works in the places that use those maglevs. Fundamentally: magnets want to pull things, more reliably than they want to push, but you can’t pull a train upwards without it being unstable, wanting to jump-up further if it hits a bump.

Enter static electricity. The repulsion between plates with the same charge means that, in a tunnel full of extra electrons, in a barge-car that’s coated in extra electrons, those electrons push all the other electrons away, and you float as if you were in water. By that I mean: you would ‘wobble’ a little if you were disturbed, and you need ballast to keep from tipping-over, while most importantly: if you start to sink, then the force of static repulsion increases because you come closer to the canal-bottom, creating a boost of force to lift you higher. No worrying about ‘balancing the magnets as passengers board on and off’ because it self-levels! And, if the barge starts to rise too high, well, then it’s further from those static charges beneath it, so it feels less ‘buoyancy’ from them, and sinks back down. When a force pushes you away, yet that force weakens with distance, then there is a natural equilibrium, regardless of which force you decide to use when pushing back. Those static charges, creeping up the walls of the canal, are also naturally buffering against the forces of turning corners — as you turn, and the barge swings close to the outside wall, its proximity increases the static repulsion, pushing the barge back on-track. Easy!

You only need to point-at an electrical insulator with a beam of electrons (19th-century tech does that well enough) to accumulate a charge on its surface, just like rubbing a balloon to your head. The hyper-barge could spray its upcoming canal section with electrons just before driving over them, to ensure that the necessary charge is maintained. The number of electrons needed to lift the entire barge is actually minuscule, and would fit on a small battery, even for cross-country trips spent spraying. Really? Yeah, really — a single Coulomb of electrons (even small supercapacitors will hold dozens of Coulombs or more) pushing against another Coulomb’s worth of charge, generates a repulsive force equal to 800,000 TONS. Static electricity is crazy strong!

Thankfully, electrical insulators are the same family of materials that all our cheap, abundant, durable, strong building materials come from! You can even build the tubes out of hemp-and-seaweed epoxy, if you want, or reinforced layers of cardboard. The insulating structure is just the same cheap stuff we already use, poured or paneled into a vaguely ‘canal’ shape, even flexing a bit for earthquake resilience, with a dome over the top, and vacuum pumps every now and again. That’s a hyperloop I’m sure we can manage. :)