What would happen if you shot an iron bolt from a railgun at 100+ Kilometers per Second?

Question

Will the bolt vaporize? Will there be a flash of light? Would there be a deafening sonic crack from the rapid expansion of air? How wide would the vapor trail from a 4mm bolt be (ballpark)? How far will it fly before its energy is dispersed in the atmosphere? How near a miss would be dangerous to a human? Deadly? Anything else I should know?

This is going to be my sci-fi weapon, so I want to know how to describe what will happen. I know the energy requirements are enormous, but the Star Wars hand blaster *supposedly* has an average energy output around 8-10 megajoules, which I remember being about a 4mm X 2cm iron bolt at 125 kps.

*The marksman need not fall backward: recoil is absorbed by a heavy metal lug of carefully calculated mass, which moves back extremely quickly with each shot, and is replaced *relatively* slowly after each shot.
This also serves as the action bolt, whose movement allows the next projectile bolt to be pushed into the breech...

Answer 1

I hate to burst you bubble, but your railgun isn't happening. The bullet would be vaporized before it left the barrel. read on if you want to know why.

Let's say you want the barrel to be 1M long. Now, lets say you have access to magnets that produce a field with a strength of 1T(which is big, by the way). I don't know how heavy your bolt would be, but let's say it weighs 1g.

Now, the force on the projectile, while it is in the gun, is equal to the current though it, times the magnetic field, times it's lenth, which you said is 4mm.

so, F=IBL

now, the total work done on the bullet by the gun, is the force times the barrel's lenth, so

W=IBLD

The kinetic energy of the bullet, (1/2)mv^2 is equal to the work done on it, assuming no friction.

so,2 IBLD=mv^2

solving for I we get I=( mv^2)/(2BLD)

Putting in the numbers i gave earlier, you get that the current through your bolt is 1.2 billion amps. your iron bold won't be able to survive having 1.2 billion amps go through it.

Answer 2

An interesting hypothesis, but I don't see how it would work in reality.

Roughly, your bolt would be
m = 0.002 kg
v = 100,000 m/s
p = 200 kg*m/s
KE = 10 MJ

That momentum is roughly 20x greater than a fairly powerful rifle, so it would have 20x the kick. Even a "heavy lug" wouldn't protect you from the kick of 20 rifles at the same time!

10 MJ is the equivalent of 1/4 liter of gasoline (or several kg of batteries). Carrying half a pound of fuel for every shot would be somewhat impractical for many situations.

100,000 m/s is faster than a typical meteor, plus the atmosphere is much thicker here than where they enter the atmosphere, so the friction & heating would be much more. I don't know just what this would do, but I expect the bolt would rapidly vaporize, create a lot of light, and create a lot of sound.


Good luck, but I don't know how realistic your weapon would be....

Answer 3

I heard somewhere that above a certain speed, the range of a given projectile in the atmosphere becomes independent of its speed. For example, if you double it's speed, it just burns up twice as fast and goes the same distance. It's a good distance though (kms).

BTW, the hand held SW blasters couldn't be 10MJ. That's about a stick of dynamite. People's guts would be blown all over the place with from the steam explosion of a well-centered hit, and misses would destroy whatever structure they were in and kill people with frag. 0.5 MJ is more like the effect I was seeing.

Answer 4

Not with our gift technological know-how despite the fact that given sufficient time an ion engine (a few elevated items are being built) would succeed in that pace utilizing steady very low acceleration. The difficulty with top speeds like that's any vessel could be sterilized by way of the radiation created by way of influence with hydrogen molecules that are traditional and the vessel could be destroyed with its first influence with a work of grime. That is without doubt one of the principal engineering disorders related to theoretical interstellar journey. Starfleet vessels on Star Trek got here ready with shields for such disorders. Unfortunately shields are a technology fiction authors answer that does not look to have a truly global likelihood of life.

Answer 5

It takes a temperature of 1811 K (1538 °C, 2800 °F) to melt iron.

So I would suspect the surface may melt because of the friction in the air and some droplets may form, but because of that same friction, there would be an important deceleration so the temperature is likely to cool down fairly soon.

Answer 6

are you serious?

Answer 7

oh. my. gosh.
ho. ly. crap.