magnetic armor

Any one ever think about it or the design? I thought, maybe have a strong magnetic field generated seconds before a strike which would slow down or change the direction of a incoming bullet or shell. I know it would reek havoc on the onboard computer systems and electronics, but maybe it would work. Say for an airplane or a tank.

Most of the materials that people shoot at vehicles are weakly diamagnetic, so TECHNICALLY, a strong magnetic field would repel them; it's just that the effect would be completely negligible at field strengths that don't RIP THE IRON OUT OF THE HEMOGLOBIN MOLECULES OF EVERYONE NEAR THE THING, (or similarly ridiculous feats).

A very strong neodymium boron permanent magnet can repel graphite, a strong diamagnet, at an acceleration of 9.81 meters per second at a distance of about a millimeter. The effect is a little stronger closer to the magnet, and drops off sharply further away. You would need an absurdly powerful electromagnet to just make a measurable change in the velocity of an incident round.

An MRI machine contains a very powerful magnet, with field strengths measured in Tesla. To get that, it has to be a superconducting coil, which necessitates cooling with liquid helium. In addition, as it must be a coil, it represents an inductance. A big inductance. That means that it can only be charged so fast. At ridiculous field strengths, I doubt an absurdly powerful magnet could be brought up to full power in time to stop a projectile.

Pretty much: no it wouldn't work, and magnets barely even work that way. Except at some cool science demonstrations levitating cubes of graphite or bismuth over superconductors, when was the last time you saw a magnet repelling anything besides another magnet that happened to be facing the right direction?

The Mythbuster Did this on Episode 59 and they BUSTED the myth.


Annotated Mythbusters

Electro-magnetic Watch Myth: An electro-magnetic watch can deflect bullets In Live and Let Die, Q gives Bond an electromagnetic watch. In a deleted scene, Bond uses it to deflect a bullet. In other scenes, the watch pulls down a zipper on a woman’s dress and pulls away his boss’ teaspoon from across the room.

Exact replica of the watch from Live and Let Die Jamie found an electromagnet small enough to fit in an exact replica of the watch from Live and Let Die. He ramped up the voltage 5x to give it a resulting field of 575 gauss. For comparison:

* Earth: 1/2 gauss
* fridge magnet: 10 gauss
* junkyard magnetic crane: 10000 gauss

They rigged up a remote firing control on a pistol so that they could have precise control over each firing. Two firings showed that the bullet closely followed the same trajectory each time.

* watch (575 gauss): With the watch in place, there was no change in the bullet’s trajectory: it went through the same hole as the bullets before.

* big electromagnet (3200 gauss): went through same hole

* 10 neodymium iron boron magnets (each magnet can lift 350lbs): the bullet actually dipped slightly and was sent flipping into the target. The hold was slightly lower on the target

* 10 neodymium + 3 even bigger magnets (60000+ gauss): Adam added three even bigger magnets (3x as thick) to the end of the row of magnets. The bullet was pulled down far enough that it hit the top of one of the last magnets.

BUSTED

ok, what about explosive armor to repel a round? That when a round strikes a directional charge would cancel out the incoming round?

reply to post by christopherledwards


That's reactive armor, and it's pretty heavy and really only practical for something large with a very strong, solid backing to put it on, like a tank or APC. The fronts of Russian MBTs are always covered with the stuff. It comes in blocks. The Abrams tank has it available as an add-on kit, but it's generally thought to be unnecessary for general use.