Most Recent Iteration of the Navy Railgun!

I said look at the whole, battery bringer-upper, not the hole.

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Um, you mean like discussing the numerous technological advancements needed to miniaturize a rail gun? Or pointing out that a principle that is limited only to integrated circuits is not related to the needed technological advancements? How much more can one look at the "whole"? Applying agricultaral advances to rail guns is not looking at the whole. Its comparing apples to robots.

Moores law originally refered to the number of transistors in a given space, or processing speed/ chip performance, but it has been shown to apply to many aspects of digital technolgy...batteries are not so much a digital technology as they are a chemical technology...especially car batteries
As one poster said these things dont really run off batteries...batteries out put a lower amount of power over an extended time...they need capacitors that release a stored charge in one massive burst
Heres an example
when you put a huge load on a battery the voltage drops and cannot adequatley supply the draw...when a large car stereo is run from the battery to an amp to a large draw subwoofer, you can see the headlights dim everytime the sub hits...thats why high quality sub setups use capacitors

"Velocitas Eradico"... Speed Destroys

I believe this prototype is built by BAE, the rumor is that General Atomics is delivering their prototype to be tested shortly.

I'm not a physics major but wouldn't the recoil from a small arms version of a rail gun (say 1/3 a .22LR sized projectile) would probably throw you back 20 feet or so? So probably not going to be handheld. The recoil would probably kill or cripple you.

Darn.... It would be pretty cool to take out a tank with a rifle. I'd name my rifle "Tiananmen Square; part 2".

Perhaps a very overbuilt turret mounted on a truck?

Force going in = force coming out. (Newtons 2nd law)
Mass*acceleration = mass*acceleration. (Conservation of energy)
Small mass, fast acceleration (bullet) = Large mass, slow acceleration in opposite direction (recoil)


A railgun works by inducing a large magnetic field through the projectile, using eddy currents in the 'rails' to propel it along at a very high rate of speed. The concept was discovered a long time ago.

The "fire" you see in the video is part of the projectile being vaporized by the large current flowing though it. Though for the Navy design, they most likely have a 'plunger' that the current flows through, so the projectile (which may house an explosive charge) does not complete the circuit for the electricity.

SCIENCE!

@Hugo

Say the 'device' blew you back at 4m/s for 2 seconds (total of 8m, bout 24ft)
I weigh 74kg (165 lbs, I'm scrawny)

So the total momentum imparted on my body would be 296kgm/s.

A 40gr 22LR Bullet (divided by 3 as per your scenario) weighs 0.000866666667kg

Basic algebra says m1v1=m2v2 sooo

74kg*4m/s = 0.000866666667kg*v2 Where v2 is the velocity of the projectile...

Solve for v2 and the projectile is moving at 341,538m/s OR 1,004.52 times the speed of sound OR 1,120,531.5 feet/s Yes, thats 1 million feet/s

The "fire" you see in the video is part of the projectile being vaporized by the large current flowing though it. Though for the Navy design, they most likely have a 'plunger' that the current flows through, so the projectile (which may house an explosive charge) does not complete the circuit for the electricity.

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The fire is metal vaporizing off of both the projectile and conductive rails inside the barrel and becoming plasma due to the huge amount of electricity and friction involved with a firing.

The projectiles so far are nothing but large, aerodynamic hunks of inert metal. Anything reactive inside the shell would probably prematurely detonate due to the violent acceleration and heat.

My Sister's Husband

used to work on a railgun at Los Alamos, IIRC they got projectiles up to about 10% of the speed of light.
They were interested in high speed impacts and the problem of intercepting incoming ICBM warheads.

svtruth said:

used to work on a railgun at Los Alamos, IIRC they got projectiles up to about 10% of the speed of light.
They were interested in high speed impacts and the problem of intercepting incoming ICBM warheads.

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Uhm. No.

the speed of light * .1 = 29,979,245.8 m / s AKA Mach 88,000 or 70 million MPH.

My sister's husband used to work on a railgun at Los Alamos, IIRC they got projectiles up to about 10% of the speed of light.
They were interested in high speed impacts and the problem of intercepting incoming ICBM warheads.

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My sister's husband's only brother-in-law (me) thinks not.

Why does the projectile in the video look like a flying hammer?
You'd think an aerodynamic shape would help performance.

twofifty said:

Why does the projectile in the video look like a flying hammer?
You'd think an aerodynamic shape would help performance.

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At over 8000fps it probably doesn't matter much. The friction with the air will melt the projectile into an aerodynamic shape.

posted via tapatalk using android.

tyeo098 said:

Uhm. No.

the speed of light * .1 = 29,979,245.8 m / s AKA Mach 88,000 or 70 million MPH.

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Seeing as the hadron collider at Cern has trouble getting a stream of just a few particles that fast....

I'm thinking the dudes brother in law is being a bit bombastic

"Solve for v2 and the projectile is moving at 341,538m/s OR 1,004.52 times the speed of sound OR 1,120,531.5 feet/s Yes, thats 1 million feet/s"

Wow ! at that velocity would the projectile follow the curve of the earth ? Kind of a very low orbit ! Kevin
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I think the curvature of the earth is about .16 meters/kilometer. That math makes my head hurt ! Kevin

It sure ain't no Paris gun or buggy whip, that's for sure. One thing that's always bothered me with these systems is that they are reliant on line of sight to a certain degree.. if one effected plunging fire, I wonder how effective it'd be. We have everything from mortars to nap of earth missiles that can do a pirouette, go straight up and then straight down etc. etc.

One thing that's always bothered me with these systems is that they are reliant on line of sight to a certain degree..

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Not at all; you could certainly lob a railgun projectile at a 30+ degree arc, but the problem is that due to the extremely high velocity, you have to be aiming at a target hundreds of miles away at least. At a certain point you're looking at suborbital ballistic projectiles.

^
I understand. Plunging fire is usually/traditionally pretty close.. due to terrain and or obstacles.

You'd have to aim it straight up to get a hit over yonder hillock and hope you got your dope right.

SEE IT LIKE A NATIVE said:

"Solve for v2 and the projectile is moving at 341,538m/s OR 1,004.52 times the speed of sound OR 1,120,531.5 feet/s Yes, thats 1 million feet/s"

Wow ! at that velocity would the projectile follow the curve of the earth ? Kind of a very low orbit ! Kevin
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Earth Escape velocity is 11.186 km/s or 11,186 m/s.

At a speed of 341,538 m/s... roughly 30 times the speed needed to escape the gravity of earth and go out into space.

It wont follow the curvature, it wont put you in LEO. It'll send you straight up, and you'll keep going.

I wonder if one would need a direct hit or would the/a shockwave down a wayward missile. A laser only "warms up" the skin a bit and the stressed member/whole contraption fails.

I'd say right now this system is too blunt to effectively shoot down missiles. It throws a several kilogram brick of aluminum at high velocity. It a gun with no T&E or aiming system...little more then a technology demonstrator. One of the Navy's proposals was to use guided projectiles launched by rail guns to effect shore bombardment from several hundred miles at sea. Guided projectiles are needed to ensure pin-point hit probability, and the sheer velocity of the projectile would be the actual "payload" (see what happens when an asteroid slams into the earth!). This would make a good surface-to-surface weapons system, since you have the range of a anti-ship missile, but unlike a missile it could not be effectively shot down by a CIWS like a missile can be.

Power for this thing would probably be derived by a nuclear reactor feeding into capacitor banks. Recharge rate of the capacitors is your only limitation to fire-rate. For smaller energy applications, (going form a multi-Kg slug to something the size of a .22) you could keep the rails indefinitely energized and have a basically particle-beam like fire rate. Ie can fire as fast as you can load rounds into the breach.

Also fun fact: Get that projectile speed above .17C (17% speed of light) and you don't use E=1/2MV^2, you have to use E=MC^2.

-v- said:

I'd say right now this system is too blunt..

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I understand what you're saying.. it's "dumb". However, back to the literal "bluntness" (of the projectile itself), perhaps it is to create a shockwave. Never know.

Imagine APFSDS out of that.

That is very cool.