Navy tests rail gun

http://news.yahoo.com/u-navy-test-futuristic-super-fast-gun-sea-202608368--sector.html?vp=1

by zafka • 12 years ago

57 100 12 years ago

news.yahoo.com

netcraft• 12 years ago

I have been hearing about rail guns for years - so its a little surprising to me that the projectiles still cost 25k and they don't expect them to be on ships till the end of the decade.

imdsm• 12 years ago

There isn't any immediate need for this, and so it isn't rushed. If all of a sudden things changed, and they needed the tech, it'd get rushed through. But why run when you can walk and still make it?

bluedino2• 12 years ago

> $25,000 for a railgun projectile versus $500,000 to $1.5 million for a missile

It's a lot cheaper than the alternatives.

sanoli2• 12 years ago

Exactly. For what it does, and what is used today to do it, it's VERY cheap.

penguat• 12 years ago

I'm quite sure that the 25k price could come down, if they were being manufactured in bulk. I believe it's mostly an appropriately shaped lump of metal..?

fit2rule• 12 years ago

The appropriate shaping is what costs so much, I imagine.

scottmagdalein• 12 years ago

I can't imagine the amount of electricity (even just for a split second) it would take to pull this off.

zafka• 12 years ago

In the ideal case, the math is pretty simple. The kinetic energy in 1/2MV^2 . (integral from 0 to mach 7) so if you know the weight of the missile...

ojii• 12 years ago

First sentence of the article: "The U.S. Navy is planning sea trials for a weapon that can fire a low-cost, 23-pound (10-kg) projectile"

lifeisstillgood• 12 years ago

weapon that can fire a low-cost, 23-pound (10-kg) projectile at seven times the speed of sound

340m/s ~ speed of sound so thats 10kg at 2380 m/s (wow!)

523802380 Joules = 28322000 J

or 28MJ or 28MW if it needs a whole second of power or well the output of ~1/10 second of a mid sized nuclear power station

Yes it needs a lot of power

jwmerrill• 12 years ago

Just the difference between 0 and Mach 7, not the integral.

HCIdivision173• 12 years ago

If I recall, one of the huge challenges was handling just that. Specifically, I remember something written on it a few years ago that the device was functional, but due to the overwhelming amperage, each shot fused the system up. And now I'll believe it, given that the video shows the casing partially vaporizing as the projectile is exiting.

There's something incredibly shocking about something exploding without traditional explosive chemistry. Just a monumental arc flash (or something - I don't know if it's the same mechanism).

jzwinck• 12 years ago

You don't need to imagine, we can compute it!

Mach 7 is 2382 m/s. 23 pounds is 10.4 kg.

Since k=mv^2: (1/2) * (10.4 kg) * (2382 m/s)^2 = 29504404 Joules.

That's 29.5 MJ, which is 29.5 megawatt-seconds. So it could mean 29.5 megawatts for one second, except of course the rail time is much less than one second. But who cares, let's convert to household units! 29500 kilowatt-seconds is 8.2 kWh. At an average price of US$0.13/kWh, that comes to just $1 worth of electricity to fire a $25000 projectile.

Oh, yeah, the losses. Those are probably 90% or so, so let's say $10. And mark it up a factor of ten because the electricity is on a boat, so $100, and a factor of 50 because it's a weapons system. So ballpark $5000 in electricity TCO to fire the $25000 projectile.

bluedino2• 12 years ago

The Popular Mechanics article from a few weeks back said 6 million amps per shot

evli• 12 years ago

Metal Gear?

dm23• 12 years ago

This is the type of ship that it will be mounted on: http://en.wikipedia.org/wiki/Spearhead-class_Joint_High_Spee...

I always assumed it would be put on a Littoral class ship. I'm guessing that the ship is going to be dedicated to this weapon and that's why it wasn't put on a carrier or LCS for testing.

How is it going to be powered? Will it have it's own dedicated nuclear reactor and a huge array of capacitors? I wonder what the time between shots will be.

Here are some nice pictures of the latest version, still amazing that it has become compact enough for a ship in such a short time. http://www.gizmag.com/first-industry-railgun-prototype-launc...

icegreentea• 12 years ago

They pretty clearly say that its being put on the Spearhead for testing because it has the space for it. And given all the problems they're having on the LCSs, I think the last they want to do is is to do testing of experimental weapons on it.

As for power, the LM2500 in the Aegis Destroyers put out 20MW. They have 4 of them. This gun puts out 32MJ of muzzle velocity. Assuming 10% efficiency, and you're at 320MJ per shot. If you ran a dedicated LM2500 per gun, that'll get you a shot every 16 seconds.

dm23• 12 years ago

The Wikipedia page says the engines are this kind and only produce 9MW: http://www.mtu-online.com/mtu/products/engine-program/diesel...

But I see what you are saying, that seems like plenty, I had always assume that it would take a huge amount of energy (I know pretty much nothing about electricity).

greedo• 12 years ago

The LCS doesn't have the room, nor the power output to use a railgun. The gun "barrel" doesn't take up much room compared to a normal 5" system, but it's the power supply that makes it unsuitable for anything short of a Burke class DDG.

alistairSH• 12 years ago

It sounds like it will be tested on the Spearhead cargo platform.

I assume as testing progresses, it will end up on other types of ship.

chiph2• 12 years ago

How is it going to be powered?

If the ship can't provide enough power, they'll probably just put some diesel generators in the cargo area.

tmikaeld• 12 years ago

I would not be surprised if "the enemy" already have the capability to create something similar.

sanoli2• 12 years ago

Everyone has something similar, and it's fully operational. But it's called a missile, and it costs 1/2 million bucks a piece.

Shivetya• 12 years ago

well they certainly can claim such, even present photographic evidence, maybe even a video. Yet you have to ask, who can verify the claim?

Now defending against such is something that would be interesting, I doubt the Navy's own laser systems, current or ten years out, would be up to it. Seems to me the best way to avoid it is not being there. So against fixed targets this is pretty much a real threat.

dm23• 12 years ago

Why do you doubt the Navy's lasers? https://www.youtube.com/watch?v=gMfYUyrKRng

Everything I've heard says that they've been very successful.

clef• 12 years ago

A bit like what Babylon 5 called "mass drivers".

Symmetry• 12 years ago

That's how the term "mass driver" was used in Babylon 5, but generally you talk about mass drivers as coilguns propelling loads that combine a magnetic component that the coilgun acts on with the actual payload, usually either for propulsion or transport. In Heinlein's novel The Moon is a Harsh Mistress the mass drivers sending products from the Moon to the Earth were re-purposed as weapons, which is probably where a lot of people first ran into the idea of electromagnetic projectile weapons, making it the default term for those some people use. Of course, to quote Niven "A reaction drive's efficiency as a weapon is in direct proportion to its efficiency as a drive."

So yes, a railgun is sort of like a mass driver. Except that railguns[1] rely on current flowing through the projectile between two rails and coilguns[2] rely on the current flowing through a loop around the projectile. And mass drivers are a sort of railgun where the projectile isn't a specially designed bullet but a spaceship or hunt of rock or pretty much anything combined with a magnetic sabot, where as this fire specially designed projectiles.

[1] https://en.wikipedia.org/wiki/Railgun

[2] http://en.wikipedia.org/wiki/Coilgun

awda2• 12 years ago

Have they fixed the problem where the gun destroys itself after three shots? (Edit: downvoters: this is a serious question. This is a (historical?) known problem with railguns.[0])

[0] https://en.wikipedia.org/wiki/Railgun#Considerations

HCIdivision173• 12 years ago

I'm not sure who would downvote that: the amperage is simply staggering! That, and the railgun project has been around for years, with the self-destruct problem being one of the more obvious issues with the idea.

Bludino notes [0] a Popular Mechanics article that quote ls 3MA, with a plan to go to 6MA!

[0] https://news.ycombinator.com/item?id=7553163

jug6ernaut4• 12 years ago

The amperage is not the issue(main issue at least).

The way a rail gun works the projectile(or its casing) must make physical and solid contact with the barrel. This is because the electric current actually flows through the projectile from one rail to the other rail[1]. This produces huge amounts of wear on the barrel, making it extremely difficult to maintain the barrel. Both in form and in being able have the projectiles make solid contact.

[1] http://upload.wikimedia.org/wikipedia/commons/9/9a/Railgun-1...

edgarallenbro• 12 years ago

$25,000 for a single projectile is "affordable"?

Why do I feel like I'm living in a madhouse?

aet• 12 years ago

1 Tomahawk missile is approximately $500k (and up)

JoeAltmaier5• 12 years ago

A single-use anti-tank weapon costs $50,000, and worth every penny if you're the infantryman and the tank is heading toward you. Its dirt cheap at the cost, considering the price of a tank.

Same for the railgun. They are shooting at million-dollar targets.

PavlovsCat3• 12 years ago

Increasing the costs for other tax payers does not make it cheaper though. Furthermore, the weapons cost the same wether they are fired at an approaching tank, into the air, at a bunch of baby seals, or not ever. It's not like weapon peddlers buy back the unused stuff at full price, do they.

pmorici2• 12 years ago

"worth every penny if you're the infantryman and the tank is heading toward you"

To bad it isn't cheaper we could give every infantryman two! In all seriousness though if you are an infantryman in a Malaria infested swamp anti-malarial drugs are worth every penny too but the production of those are subject to competition so luckily they only cost pennies a pill and every soldier can have as many as needed. The missile's value to a soldier is not a justification for it's cost and if anything the high cost of something like that is detrimental because if it really is that great it means that not everyone can have one.

mcphage• 12 years ago

Its dirt cheap at the cost, considering the price of a tank.

And the price of an infantryman.

skywhopper• 12 years ago

The question is... how much does the railgun itself cost per shot? $25,000 per round is cheap enough, but what's the impact of each firing on the gun?

Missles and shells are expensive mostly because they have to propel themselves, but they benefit from the fact that that propulsion system only has to work one time. A useful railgun will need to be able to fire thousands of times without major maintenance before you'll start seeing any cost benefit to cheap ammunition.

loceng• 12 years ago

$2,000 + $23,000 military-industrial complex fee.

mkr-hn2• 12 years ago

$25,000 to tear another ship apart at 7 times the speed of sound is a bargain.

Qworg• 12 years ago

In comparison to a million dollar missile? Yes.

chao-• 12 years ago

In terms of Defense budgets, that is indeed affordable.

Expenses for Exploration and Production (i.e. upstream oil & gas) operate on similar orders of magnitude.

lmg643• 12 years ago

Considering that the rail gun projectile is basically a hunk of metal, $25k does seem really expensive. No gunpowder, nothing. All the work is in the railgun.

JoeAltmaier5• 12 years ago

The projectile is a marvel of materials engineering. It has to accelerate to Mach 7 in a few feet, survive friction with the surrounding air for 100 miles, and have enough remaining core to deliver sufficient kinetic energy to be worthwhile.

Its definitely not just a chunk of barstock milled to a point.

etherael• 12 years ago

This is the more interesting question to me, not "is it cheap in comparison to what it's targeting or the alternatives" but "is it cheap based on the cost of production".

25k for a hunk of metal does seem like a very strange price, perhaps there's something more exotic to it than meets the eye?

pmorici2• 12 years ago

When they said that my immediate thought was, yeah a US missile costs millions but is that is representative of the cost of production of a Chinese missile? America's enemies don't buy their missiles from American defense contractors. They already produce electronics a good deal cheaper than the US and that isn't even considering the beltway bandit markup.

Also all the comments saying that this is cheap compared to some other US weapon that is probably similarly overpriced are just silly. These sorts of things are not subject to the kind of competition that normal goods are. Just look at the cost of space flight for companies like SpaceX and Virgin Galactic compared to NASA's which relied on defense contractors until SpaceX came along.

http://www.reuters.com/article/2013/09/27/us-turkey-china-de...

PavlovsCat3• 12 years ago

Well, transfering money from tax payers into private hands is a lucrative business. Don't attribute insanity to what cold malice explains.

allworknoplay• 12 years ago

Because you are. I'm with PavlovsCat -- the relative price comparison is being used to sell extraordinary profits, and otherwise smart people just eat it up.

sjtrny2• 12 years ago

This is not news. This rail gun tech has been around for years. Here is a video posted in 2012 which shows the exact same gun: http://youtube.com/watch?v=eC2hu9bildA

yread• 12 years ago

Interesting it's exactly the same images. Why is this news?

sjtrny2• 12 years ago

I think the US Navy wanted some positive press coverage.

fbomb• 12 years ago

The BFG is still a better weapon.

zerohm• 12 years ago

So how is the accuracy?

How many shots will it take you to hit a missile 50 miles away? 100 miles? Parallel vs perpendicular path?

hawleyal• 12 years ago

There is no one to shoot.

JimmaDaRustla• 12 years ago

There doesn't need to be anyone to shoot - it is there to prevent those who attempt to be something to be shot at.

Remember, it took one bomb to end WWII.

qbrass• 12 years ago

Two bombs.

iliis2• 12 years ago

Can somebody please add a warning that there's an autoplaying video? It's a bit awkward if your phone suddenly starts talking about guns when your standing in line in a bank :/

Edit: A video tag would be nice in general for mobile users.

probably_wrong2• 12 years ago

Aren't you supposed to turn off your phone while inside a bank?

iliis2• 12 years ago

I haven't been in that many banks but I've never been at one that tells you to turn off cellphones , neither in Europe nor here in Africa...

mrottenkolber• 12 years ago

Being a radical pacifist I aide: I always wanted real rail guns (too much quake).

fasteddie31003• 12 years ago

As a lover of technology and science fiction I love this railgun. But as a taxpayer and pragmatist, I really think it is a waste. I can't see this being as accurate as a guided missile over long ranges, which is the most important thing for modern combat. So that leaves it as a good alternative for short range attacks, which I doubt it will ever be used in combat for.

mkr-hn2• 12 years ago

I doubt this is an issue with a projectile moving seven times the speed of sound as long as the targeting system is accurate. Even if a warplane could be built to sustain mach 7, how would it turn to avoid the projectile?

Retric2• 12 years ago

Drones don't need pilots which means they don't need pilot training which changes the economics of air-combat. For around ~100k you can build a long rang self guided drone which would be almost useless vs an aircraft carrier or a modern fighter. However, for ~10 billion you can have 100,000 of those suckers and the US does not have anywhere near that many air to air missiles and it's not going to take anywhere near 100k of them to takeout an aircraft carrier.

JackFr3• 12 years ago

However, $10 billion is a big number for everyone, including the US and China, although for them its at least possible. It's 150% of Iran's military budget and about 80% of North Korea's entire GDP.

oakwhiz• 12 years ago

US does not have anywhere near that many air to air missiles

That is true, however the US also possesses a large number of anti-aircraft guns, with plenty of bullets. :-)

harywilke• 12 years ago

i wonder about his statement that not a thing in the sky would survive at hit. from the video of it punching through the reinforced concrete walls, it seem that there is very little damage to the wall besides the obvious hole. sort of like the shaolin monk throwing a needle through glass. https://www.youtube.com/watch?v=eW_97D0hLBc but i'd guess this is more a question of what kind of target they are shooting at. they present incoming missiles (small and mobile) and something over 100 miles away (big and stationary?).

JoeAltmaier5• 12 years ago

Targeting is certainly important and remains to be seen if they're up to it. But Mach 7 means you only have to get a fix on it, and a rough estimate of its speed; the missile will arrive in milliseconds and the target won't have moved very far.

But is there anything in the air that has enough extra parts that it can survive a 10-inch hole through and through, and destruction of everything in between? Certainly not any missile.

arethuza2• 12 years ago

Mach 7 is 5328mph

100 miles at 5328mph is going to take ~1 minute

JackFr3• 12 years ago

The first operational beam weapons and rail guns really bring out in stark contrast that all a modern weapon system is, is the ability to reasonably safely store potential energy 'here' and accurately release it 'there', with hopefully catastrophic consequences.

What railguns and beam weapons do, is weaponize nuclear reactors and gas turbines, reducing the need for propellants and explosives. While it's unlikely that this will allow the aircraft carrier to regain the place it once held, it seems likely in the future that massive power generation capability will become more and more important.

jug6ernaut4• 12 years ago

While it's unlikely that this will allow the aircraft carrier to regain the place it once held...

Care to elaborate on this? I was under the impression aircraft carriers were still our best general purpose military tool? (wartime/peacetime/force projection/ect)

div• 12 years ago

Wikipedia has a good writeup of the Millenium Challenge 2002 wargames, where a large fleet was basically destroyed by assymetrical guerilla tactics (small boats, low tech communication):

http://en.wikipedia.org/wiki/Millennium_Challenge_2002

macavity232• 12 years ago

They're great against a low-tech adversary, but against serious ballistic or (some) cruise missiles, they're just slowly-moving seaborne apartment blocks. Good writeup here:

http://exiledonline.com/the-war-nerd-this-is-how-the-carrier...

JackFr3• 12 years ago

Admittedly, I have no special expertise. My understanding is that while for certain kinds of force projection, they are the only game in town, they are such a rich, fat target, a larger and larger portion of their operation (in terms of manpower, arms and electronics) gets devoted to defending the carrier, and this squeezes out the force projection capability. I believe the cost of production of an aircraft carrier is around $12 billion, and I'm not sure if that includes the ~$1 billion worth of aircraft on board.

bunderbunder2• 12 years ago

while it's unlikely that this will allow the aircraft carrier to regain the place it once held

The very first thing I thought after all that waxing poetic about destroying a $2M missile with a $20,000 slug was, "OK, now what happens if the enemy launches a couple missiles at the same time?"

And heck, while we're at it you probably don't need such sophisticated guidance equipment if you aren't perching all your eggs on top of one rocket. . . so can this thing achieve a high enough rate of fire to put even a tiny little dent in a large salvo of cheap missiles?

pistle• 12 years ago

These are interesting stories. I find mass publicity of war tech interesting. This one has been a long time coming as noted by all the "this is old news" responses.

Who are the intended audiences? What is the intended effect? Warnings to the competition? Psychological effect on economy-draining military efforts in places like N.Korea and Iran? PR/Sales efforts to the military funding and recruitment apparatus?

Pxtl• 12 years ago

Obvious question: when was the last time a US ship actually shot a big artillery gun at a target?

jug6ernaut4• 12 years ago

Gulf War.

https://www.youtube.com/watch?v=TTetKxtmI9c

drmarianus• 12 years ago

The gulf war, apparently. However, that's not the point. If you watch to the end, the officer explains that the cost of one of these slugs is only 25k yet it performs the same role (and more) of a multi-million dollar missile that a ship can only care a handful of.

And boy has the US Military fired a lot of missiles.

headShrinker• 12 years ago

I'm sure someone here knows better than me, but the navy's big guns are capable of shooting a 2,000lb projectile 25 miles with pretty insane accuracy. I believe the navy uses these guns all the time. Is sounds like the rail gun will be used for a different purpose than the big warship cannons though.

ogig• 12 years ago

This kind of progress saddens me. Who is going to be the target of this weapon? Also think in all the human and material resources involved in creating this, i can't help thinking how many "good actions" could be done instead. How many medical supplies, food and clean water could be distributed with the $$$ used in the development and usage of this.

I'm probably just a naive pacifist, but I think the world would be a better place if Americans stop producing weapons. Especially of this kind.

I appreciate the amazing science behind the nuclear bomb, drones or railguns, but i would rather keep it on the scifi parcel and wish the were never created for real.

Again, I'm probably naive.

chiph2• 12 years ago

The military would agree with you. After all, they're the ones with the greatest chance of getting killed in a conflict.

The problem is the policy makers tend to regard them as the first option (when they should be the last) for a number of reasons. The first one in my mind is because the number of senators and congressmen with children in the military can probably be counted on less than two hands. None of them would publicly state that they want to see Americans killed in a war, but their actions say different. Dunbar's Number[0] at work.

The other reason is that the US military is amazingly successful. They've fought a two-front war, one against the fifth largest army on the planet, and defeated all opponents. And did it without putting the entire country on a war footing (conscription, entire industries being converted, and so on). So (from the politician's view), why not hand the problem over to someone who can get stuff done?

Lastly - As much as I'd like to believe the world is full of potential friends, if only we could meet and talk -- the reality is that there are a lot of people out there who hate us. Many of them because we killed a relative or friend. But some because we don't live up to their expectations. As weird as that may be. Consequently, a strong means of national defense is required.

[0] http://en.wikipedia.org/wiki/Dunbar's_number

holograham• 12 years ago

what is counter intuitive about the defense industry is that the development of new weapons like this (and the other weapons you have mentioned) have actually increased peace in the world. Certainly not the ONLY reason to be fair.

A great book on this is "The Better Angles of Our Nature: Why Violence has Declined" by Stephen Pinker. I recommend any pacifist (really anyone) read this book.

While we hear about the immense destructive power of new weapons, the reality is that they are seldom used. Most of our Defense budget is building an army that no one would dare attack. It is like our nuclear bomb policy -- 100% guaranteed retaliatory strike(s) but no first strike. This project is designed to replace expensive missiles with (relatively) inexpensive inert metal slugs that yield the same capabilities (range, stopping power, etc). This is most definitely a program that would lower costs and increase discretionary funding outside of the military.

havemurci• 12 years ago

Would this type of weapon be able to shoot satellites right out of the sky?

munchbunny• 12 years ago

It doesn't take much power to shoot a satellite out of the sky. The hard part is actually hitting it.

Let's say you're aiming at a GPS satellite in geostationary orbit. According to Wikipedia (http://en.wikipedia.org/wiki/Geostationary_orbit) you're trying to hit a target that is 20,000 miles up in the sky moving at about mach 10, and the target is the size of a car. We don't have the tech for that kind of dumb-fire accuracy, even if you fire the gun from above the atmosphere. At 20,000 miles, you would need to reliably place a shot within slightly less than 1/1000th of an arcsecond.

In order to hit a target under those conditions, you would need a projectile that can do course corrections on the way to the target. Like a missile.

malandrew2• 12 years ago

Interestingly this story makes me wonder whether economic consequences even enter the picture when choosing to engage. I never would have imagined an admiral asking themselves "Is this worth the cost of a $1.5 million missile?" I reckon that it would be a binary decision based on threat alone. Are there any guidelines in the military where the commanding officer is instructed to perform any sort of cost benefits analysis when making the decision to engage a hostile?

Would a dramatically lowered cost greatly increase the likelihood that the navy will be more willing to act as an aggressor?

Navy tests rail gun

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