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A First Look at America's Supergun
- zellyn 10y ago"The Navy now believes it has a design that soon will be able to fire 10 times a minute through a barrel capable of lasting 1,000 rounds." So the barrel lasts just over an hour and a half?
- aljones 10y agoIs there more to your question than is my math right?
- zellyn 10y agoI was astounded at the low number of shots per barrel. As the other replies to this comment show, it's actually quite good. Surprising!
- RhysU 10y agoNotice no details on the barrel. Everything is about making it last. That many shots from a high power rail gun is nuts.
- saulrh 10y agoDuring their service in WWII, the 16-inch guns on the Iowa-class battleships had a life of about 300 rounds. They didn't reach their current 3500-round lifetime until we figured out polyeurethane bags in the 70s. So 1000 rounds is solid. https://en.wikipedia.org/wiki/Armament_of_the_Iowa-class_battleship#Turrets https://en.wikipedia.org/wiki/Armament_of_the_Iowa-class_bat...
- lobster_johnson 10y agoI assume WW2 ships simply stocked a bunch of gun barrels to replace the ones they wore out?
- GunboatDiplomat 10y agoHave you ever seen, in person, the scale of a 16 inch 50 Caliber gun? They're not field swappable. The barrel is about 67 feet long and weighs 120ish tons.
- dgacmu 10y agoThink of it instead as: The ship can fire 10x as many rounds before needing to resupply as it can with today's technology. The resupply also happens to involve replacing the barrel. Today's 5" guns have to have their barrel replaced every ~7000 rounds anyway (source: http://www.navweaps.com/Weapons/WNUS_5-62_mk45.htm http://www.navweaps.com/Weapons/WNUS_5-62_mk45.htm ).
- jessriedel 10y agoIn terms of firepower and reusability, you should compare these to missiles rather than guns. (Each round could sink a ship.) The barrel is an expendable component.
- dredmorbius 10y agoWhat's the scenario in which a vessel would be faced with 1,000 targets (per barrel) in an engagement? I suspect the Navy have some records on firing rates achieved in actual battle situations. The relationship between theoretical firing rate and actual firing rate is often distant. You might find it more useful to read this as a weapon capable of firing not more often than once every six seconds, and having an effective barrel life of 1,000 rounds. Those 1,000 firings could well be spread over months or years.
- TeMPOraL 10y agoIt's kind of like with automatic weapons - some of them are capable of firing so fast that they'd eat through your magazine in a second or less. That has little to do with how they're actually used though.
- m-i-l 10y agoMight a bigger challenge be the power source? If each firing requires 25MW, then 1000 shells would require 25GW, which is equivalent to the output of several large nuclear power stations. Edit: Apologies, basic mistake, mixed up power with energy. Thanks for correcting.
- malisper 10y ago> If each firing requires 25Mw, then 1000 shells would require 25Gw That's not how power works. Power is energy/second, so if one each firing requires 25Mw, firing every round requires 25Mw. Edit: Although after doing some calculations, firing 1000 shells would require 22 billion joules of energy, which is about the same as the energy released during nuclear fission of three grams of uranium.
- deleted 10y ago[deleted]
- madmax96 10y agoHow plentiful is Uranium? I'm not a nuclear engineer, so the 3 grams metric isn't meaningful to me -- is that a considerable amount?
- Roboprog 10y ago3 grams is between about 1/6 and 1/8 once. Of course, only a small portion of uranium in a reactor core is converted to something else. After that, they replace the fuel as its output drops a bit. Disclaimer: I don't know enough to check the "grandparent" post's math. I'm assuming the calc is right in that it's the fission energy, and not total destruction of matter E=mc^2 / matter-antimatter style.
- m-i-l 10y agoThanks. That helps with my original question - how portable will this be? If it just needs a very small nuclear reactor with a tiny amount of fuel, then they should be able to have a power source "that generates 25 megawatts" and can "fire 10 times a minute through a barrel capable of lasting 1,000 rounds" on a ship. But what about a truck? Having a weapon with a 125 mile range isn't necessarily all that great if it is too big and heavy to get within 125 miles of most of the things you want to shoot at.
- azinman2 10y agoI look forward to the day that the great weapons race is for more weapons like this that aren't radioactive, biological, or otherwise impact the environment beyond the war itself.
- antoinealb 10y agoI highly doubt that it does not impact the environment. Most ammunition contains lead or some other forms of heavy metals, which are pretty toxic.
- Razengan 10y agoTiny automated robot flies that seek out enemy leaders and inject poison?
- zaken 10y agoA 25-pound projectile traveling at 4500 miles per hour carries as much momentum as a jumbo jet at cruising speed: http://www.wolframalpha.com/input/?i=25+pounds+*+4500+miles+per+second http://www.wolframalpha.com/input/?i=25+pounds+*+4500+miles+... We know the impact a hijacked jumbo jet can have on buildings...now imagine being able to sustain that level of destruction at a rate of 10 times/minute with hardly any power or material consumption.
- stavrianos 10y agoWell, I mean, you have to consume enough power to get a jumbo jet up to cruising speed.
- Bromskloss 10y agoI was under the impression that energy was a better indicator of damage, or is that more for small stuff like hand guns?
- lobster_johnson 10y agoThe destructive power of this gun comes from the energy of its momentum (mass x velocity) -- all the energy expended to accelerate it needs to go somewhere when it reaches its target. Same principle as a handgun. The difference is in how the projectile is accelerated.
- stcredzero 10y agoThe destructive power of this gun comes from the energy of its momentum Sorry, but it sounds like not all readers on this website know the difference between kinetic energy and momentum. Here's a K-12 level website: http://www.batesville.k12.in.us/physics/phynet/mechanics/energy/KENOTMomentum.html http://www.batesville.k12.in.us/physics/phynet/mechanics/ene... It has a very illustrative question: Would you rather be hit by a 1000 kg vehicle going 1 meters per second, or by a 1 kg meatball going 1000 meters per second?
- 10y ago
- NKCSS 10y agoCool, but also something that makes war even more scary. You'd use to have all sorts of things to protect you; there isn't anything that can protect you from this once aimed at you (except a pre-emptive EMP; providing they have no shielding for it). Feels weird knowing there is nothing that can protect you from it.
- Artlav 10y agoNot exactly. It can be protected from by a multi-layered whipple shield, kind of like what was proposed to protect spaceships from meteors. On the other hand, it won't be something you can line a ship or a plane with, so yeah... Always shoot first.
- stcredzero 10y agoIn conventional guns, a bullet loses velocity from the moment the gunpowder ignites and sends it flying. The railgun projectile instead gains speed as it travels the length of a 32-foot barrel Even the Wall Street Journal has science/engineering illiterate idiots writing for it? If engineered properly, a conventional naval gun will also continue to accelerate its projectile all the way down the barrel. Why does this idiot think there are various guns that have long barrels? It's to give expanding gasses a longer time to accelerate the projectile.
- edanm 10y agoYou make good points, but I wish you'd express yourself more nicely. You really don't need to call the authors idiots (twice!) To make your case.
- stcredzero 10y agoThis is how I genuinely feel about the level of scientific illiteracy our society has fallen to. We literally have people at an executive level who are functionally illiterate in science, making decisions on the basis of their ignorance. (The editors of the WSJ could be seen as examples of this.) "Solar Freakin Roadways" got almost $2 million from the public. Are we functioning with a viable educational system for a complex technological democratic society? Heck no. Even the people in charge are riddled with ignorance on basic levels. Not knowing what you don't know can literally cost untold treasure and many millions of lives. There are tons of examples of this in history. I'm pretty sure we're not doing so great a job teaching that either. And yes, it even goes to examples of basic Computer Science knowledge on HN!
- jessriedel 10y agoThe sincerity of your feelings is not the point. The point is that calling people names reduces the quality of the comments.
- TeMPOraL 10y ago
- matt-attack 10y ago> In conventional guns, a bullet loses velocity from the moment the gunpowder ignites and sends it flying. The railgun projectile instead gains speed as it travels the length of a 32-foot barrel.. This is incorrect. Most cartridges are design so that the projectile accelerates for the entire length of the barrel.
- hooloovoo_zoo 10y agoPerhaps the author meant the bullet loses acceleration over the length of the barrel?
- foota 10y agoBased on the fact that they state the railgun is different in that it gains speed over during the time in the barrel, it seems like the author just doesn't gun physics.
- geon 10y agoIt is logically false, since if it was true, the acceleration would have to be instantaneous.
- forgotAgain 10y agoDefense Industry porn.
- dredmorbius 10y agoSome equivalence values here. A typical US navy marine propulsion reactor puts out 250 MW. This railgun would require about 10% the energy output of such a reactor. A large aircraft carrier might have several cores. From the 9/11 attack scenario below, impact speed matters (kinetic energy scales with the square of velocity), but chemical reactions pack a great deal of energy. The fuel of the airliners crashed into the World Trade Center towers released some 370x more energy than the impacts themselves, though as thermal energy delivered over roughly an hour, rather than the instantaneous impact. As an alternative to missiles, the railguns would likely allow for increased firing -- a typical vessel carries fewer than 100 missiles, but could probably carry far more shells (and be capable of firing them). I'm wondering at what point increased speed means you're simply punching holes through things without actually inflicting damage -- it's the transfer of energy from shell to structure that matters. If you're targeting a deeply buried concrete bunker, this is appropriate. Residential or commercial buildings, cars, etc., will to a large extent simply get very well ventilated (though you might not want to be in the immediate enting area when this happens). Matching shell structure to target likely matters.
- LNMNMMMC 10y agoNever, more speed is good because they can program the projectiles to break apart before impact with soft targets. The limiting factor is air resistance, greater initial speeds result in more energy wasted. Also, I believe they are (were?) looking at the Zumwalt destroyer for this weapon, which actually only has 78 MW of power output.
- tonmoy 10y agoDoes power really matter? 25MW instantaneous power vs continuous/average power are different things. With modern clever power electronics you could get pretty high instantaneous power from a lower powered source. The exact energy vs time curve and desired fire rate has to be utilized to make any effective prediction I think.
- myblake 10y ago
- rsp1984 10y agoMissile defense by the railgun is at least a decade away, but Pentagon officials believe the weapon’s projectiles can be used much sooner. They are filled with tungsten pellets harder than many kinds of steel, officials said, and will likely cost between $25,000 and $50,000, a bargain compared with a $10-million interceptor missile. Learning about how expensive high-tech weapons are never ceases to blow my mind. 50k for a single bullet -- equivalent to 1 yearly median US salary. 10m for a missile -- the price of a luxury mansion or the value of a decently successful startup.
- jevinskie 10y agoConsider that an infantry rifle will cost at least $1,000. A rail gun round seems like a bargain if it costs 25-50 rifles-worth! The risk to the military personnel is also lesser than using small arms rifles.
- ryanmarsh 10y agoYes if they'd only stop throwing the rifles away after each shot.
- jevinskie 10y agoI've heard that the hit ratio of modern small-arms battle is very low. The railgun would be a much more assured strike than sending even many humans to do the job. The railgun isn't just replacing rifles, bombs, and missiles, it is replacing humans! Think of how much a wounded soldier will cost a country over the course of their life, at least if the country gives a damn about vet benefits. Of course while likely quite precise (I'd guess 10 meter CEP), it is still a very powerful weapon that could cause a lot of collateral damage. Human soldiers still have applications.
- ryanmarsh 10y agoArtillery isn't typically used to do infantry jobs. We call that a "war crime". Unless it's us doing it, then we call it "collateral damage". You are correct, most bullets fired in an infantry engagement do not in fact hit their targets. Assuming a target can even be seen. Bullets are cheap and useful for all manner of things, such as keeping the enemy's head down long enough for you to get into position to use a few bullets and kill him. ;)
- avodonosov 10y agoGauss rifle : https://en.wikipedia.org/wiki/Coilgun https://en.wikipedia.org/wiki/Coilgun
- PhasmaFelis 10y agoNo, railguns and coilguns are different. The second paragraph at your link explains the distinction.
- avodonosov 10y agoIndeed, thanks for the hint. I actually wanted to note, that electromagnetic guns is an old idea. (Even I came to it once, but of different design; and was surprised when discovered it to be already studied - in that article though they said this idea turned out to be impractical).
- dwaltrip 10y agoIt's a bit fascinating and scary how casually they talk about the weapons of China and Russia, and what we need to counter them. Do they believe there is a realistic chance of war with these countries? Or is just about using military might as a political & diplomatic tool?
- edanm 10y agoI think most people generally believe that, yes, war with other countries is possible. Considering the history of the world, and considering that wars are happening in other countries all the time, I'd personally say that thinking war isn't possible is incredibly naive and unrealistic.
- baddox 10y ago> Do they believe there is a realistic chance of war with these countries? Surely anyone looking at history learns it's not a matter of if, but a matter of when. Perhaps (hopefully!) it won't be in our lifetimes, but it's reasonable to want to stay even with or ahead of the capabilities of other powerful militaries, including ones we are currently allied or at peace with.
- curt15 10y agoThe weapons of China and Russia aren't going to be confronted only in China or Russia. At any rate, it's always good to negotiate from a position of strength.
- Teever 10y agoLet's look at this another way: Do you think that there will never be another major war? Like never, ever, ever again? Can you genuinely state with certainty that humanity is over fighting major wars -- that we've evolved past that? The answer is simply no, we haven't gotten past that point and likely never will. So in that context we should be developing weapons to fight and win wars against the most likely of threats. The most likely threats happen to be China and Russia.
- jcoffland 10y ago
- mrep 10y agoto put that speed in perspective, thats about 1/6 earth's escape velocity.
- Artlav 10y agoI'd love to know how they solved the barrel erosion problem. A rail gun is as satanically simple in theory as it is satanically hard to engineer. A coil gun won't have this problem, but unfortunately the magnetic fields are harder to get than the electric ones.
- aries1980 10y agoHow "America's Supergun" is this if it is made by BAE? https://i1.wp.com/news.usni.org/wp-content/uploads/2015/01/140708-N-ZK869-010.jpg?ssl=1 https://i1.wp.com/news.usni.org/wp-content/uploads/2015/01/1...