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The US Navy Wants More Railguns and Lasers, Less Gunpowder
coondoggie writes Speaking before nearly 3,000 attendees at the Naval Future Force Science and Technology EXPO in Washington, D.C., Chief of Naval Operations Admiral Jonathan Greenert charged his audience to reduce reliance on gunpowder in a wide-ranging speech on the future technological needs of the Navy. "Number one, you've got to get us off gunpowder," said Greenert, noting that Office of Naval Research-supported weapon programs like Laser Weapon System (LaWS) and the electromagnetic railgun are vital to the future force. “Probably the biggest vulnerability of a ship is its magazine—because that’s where all the explosives are." Weapons like LaWS have a virtually unlimited magazine, only constrained by power and cooling capabilities aboard the vessel carrying them. In addition, Greenert noted the added safety for Sailors and Marines that will come from reducing dependency on gunpowder-based munitions.
How is that fancy laser going to work when the enemy uses a smoke screen? Or a mirror?
The creatures outside looked from Alt-Right to Antifa; but already it was impossible to say which was which.
Laser are line of sight only, they can't do indirect fire. A ship would also need rail guns to launch projectiles. Its an improvement, but there will still be ammunition limits.
Why not work on the diplomacy? No country in the world has so much trouble talking to others like the US. Always resorting to violence when someone do not follow their orders. Wars going on directly or by proxy in Afghanistan, Iraq, Syria, Africa and South America and it is just a matter of time until wars are instigated in Asia. Lighting the world on fire sure are a good way of seeing to it that you have to burn gunpowder like there is no tomorrow.
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However successive UK governments have seen "improving" the navy as meaning strip it of as many ships as it can. Soon it'll consist of 2 men and a rowing boat. Oh, and one overpriced aircraft carrier with no planes that can fly from it.
Yes they are, an aluminium slug impacting the ground at say Mach 15 does not need any gunpowder to create a large hole in the ground or destroy a building, the kinetic energy of the projectile will do that all by itself.
Err, the batteries or super capacitors are probably charged up before each shot then discharge during it, so most of the time they'll do very little if you hit them with a shell.
Not all humans are created alike
Not all humans are reasonable
Not all humans are sane
Diplomacy works on humans who are (at least) sane. On the other hand, savages such as the Jihadists who recently burnt a Jordanian pilot to death are not interested in diplomacy
I understand that passifists / peace loving / tree hugging / hippie wannabe like you want peace, but let me tell you this one thing - you will only get your peace if others are afraid to mess with you
Amazing! You have described exactly how these things don't work!
I couldn't have done it better myself!
There's actually a few tradeoffs here. Unless it's a nuclear powered ship, then efficiency does matter. Fuel is much more energy dense, due to not having its own oxidiser, but railguns are fearfully inefficient. Unless they get the efficiency up then the fuel might take up more space. That said, being liquid, it fits into awkward spaces more easily.
As for power, that's an interesting one. If you look at the proposed railgun specs, the slugs have about the same kinetic energy as a WWII battleship round from at 16" gun. While the velocity of a railgun round is much higher, it doesn't weigh well over a ton. Plus, the battleship round also has about the same energy again as an explosive payload. So in practice the railgun will have about half the energy delivery capacity of a single round from a WWII battleship.
Of course, the railgun has a much longer range, a much higher speed, is much smaller and doesn't requite an unstable mix of fuel and oxidiser to be carried so that is a win.
In terms of armor, that's more or less gone from ships. The reason being that modern torpedos and some missiles which dive shortly before impact essentially make explode under the ship not against it, lifting it partly out of the water and creating a bubble which the ship falls into breaking its back. Armor is more or less worthless against that sort of attack. So if you're in a war with the USSR, there's no point in having any.
Excpet the only naval engagements from western nations in vaguely recent times have been things like the exocet missile strikes frmo the Falklands war (again less energy than a battleship round, and armor would have helped), a boat packed with explosives (again armor would have helped) and a few others. So ship armor is already more or less worthless against a modern well equipped navy, but it's probably worth having for when one isn't engaging one of those.
But back to the railgun.
There's an interesting thing that hitting a target with a high energy inert round often doesn't do a whole lot of damage. There was a case in WWII of some armed merchant cruisers (i.e. cargo ships with a couple of obsolete guns welded on) were mistaken for cruisers by some German raiders. The raiders engaged at long range with AP rounds and scored some direct hits. The AP rounds went all the way through the unarmored ships and out the other side without detonating (they were designed to penetrate a bit into armor and then detonate: the lack of armor caused the warhead to not trigger). The end result was that the ships wound up with some perfectly survivable 15" holes in them and managed to escape.
Likewise, the British army still like their HESH rounds, because the APFDS rounds (basically a long, thin very high speed slug designed to penetrate thick tank armour) have the annoying habit of going right through more lightly armoured vehicles without doing significant damage except for two small holes, where as the HESH rounds tear them open.
The cause of this is that very high energy rounds are hard to stop. Even the target has trouble stopping them, and if it fails to, then they leave with most of their energy and deliver it elsewhere.
In fact come to think of it, back when muskets were becoming obsolete, some armies found that although the modern high speed, high accuracy bullets made it much easier to hit the target, they tended to go right through people. The result being that again, the round not only had to hit a person but unlike a musket ball, had to hit something important, so there was a much higher survivability rate from people who were shot.
So, what I wonder is how the railguns fit into this. It seems that they'd be prone to very effectively making a couple of small holes in whatever they hit and delivering most of the energy into the sea or ground. Unless you actually hit the engines or some other critical piece, a ship, especially a warship can survive a surprisingly large number of holes before it is put out of action.
SJW n. One who posts facts.
Please explain to them your concept of diplomacy.
Naval gun propellant charges now use LOVA propellants (originally developed for tank and SPA munitions). These are RDX, and later, HMX-based formulations. Nitrocellulose is old-school; it went out with the last battleships. I know. I worked at NSWCIH on the project. You fail current knowledge forever.
So... How long before we build BattleMechs to carry these things for land based attacks?
> Of course, the railgun has a much longer range, a much higher speed,
The railgun range today is effectively _zero_. High velocity rounds have been launched from test guns, but none have actually successfully hit a moving target without a pre-plotted course for the target, nor have any significantly sized railguns been successfully tested from a portable platform. They also wear out so fast that the mass and resources saved on ammunition are effectively taken up by the necessary spare parts for the railgun itself. I'm afraid they're much like dotcom business plans. The drawing on the back of the napkin looks fabulous, but the actual engineering has turned out to have real limits.
but railguns are fearfully inefficient.
Compared to chemical propellants? I don't think so.
Unless they get the efficiency up then the fuel might take up more space. That said, being liquid,
I'm fairly certain the nuclear reactor that powers the guns and the ship won't be that big of a problem. They don't do it on diesel.
Armor is more or less worthless against that sort of attack.
Thats why the strengthen the keel ... 40 years ago.
I'd keep going, but I'm just blown away by how you got to +5 on this. You don't seem to know anything at all about you're talking about. You're mixing and matching things in ways that makes them all simply completely false statements.
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But that whole being a witch thing cost him the south.
Compared to chemical propellants? I don't think so.
http://en.wikipedia.org/wiki/P...
According to that firearm efficiency is not incomparable to piston engines, which is not all that surprising as the conversion of heat to motion is not dissimilar. In that case, a .300 rifle achieves about 32% efficiency.
For a fuel powered railgun, you have to first convert the fuel to heat then to motion then to electricity. The top marine diesles give about 51% efficiency, when you're preppared to sacrafice almost anything on the altar of efficiency. The likely efficiency of a naval marine engine is probably more like 40%, in which case you're already quite close to the gun efficiency and you haven't even generated electricity yet.
You've then got the capacitor bank charging, switching losses and finally the conversion of the insane current into motion.
So my guess would be that a rail gun is substantially less efficient than a conventional firearm.
I'm fairly certain the nuclear reactor that powers the guns and the ship won't be that big of a problem. They don't do it on diesel.
Well, that removes a lot of the advantages: nuclear reactors are vastly more expensive, so you've just put the price way up.
Thats why the strengthen the keel ... 40 years ago.
So why are modern torpedos designed to work that way?
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I'd keep going, but I'm just blown away by how you got to +5 on this. You don't seem to know anything at all about you're talking about. You're mixing and matching things in ways that makes them all simply completely false statements.
Touche, my man.
SJW n. One who posts facts.
There's an interesting thing that hitting a target with a high energy inert round often doesn't do a whole lot of damage. There was a case in WWII of some armed merchant cruisers (i.e. cargo ships with a couple of obsolete guns welded on) were mistaken for cruisers by some German raiders. The raiders engaged at long range with AP rounds and scored some direct hits. The AP rounds went all the way through the unarmored ships and out the other side without detonating (they were designed to penetrate a bit into armor and then detonate: the lack of armor caused the warhead to not trigger). The end result was that the ships wound up with some perfectly survivable 15" holes in them and managed to escape.
Good stuff here. I just have to add that this effect is seen throughout the age of gunpowder: unless gunnery hit the enemy magazine, all they were doing was making pinpricks in the opposing fleet. Keegan's Price of Admiralty describes Lord Nelson's fleet and the HMS Dreadnought being involved in these kinds of battles.
Populus vult decipi, ergo decipiatur...
"Force shits upon Reason's back." - Poor Richard's Almanac
The bullet in this case is just a massive piece of metal. It is accelerated to a ridiculous speed (a Navy weapon capable of hurling 40-pound projectiles at speeds of 4,500 mph to 5,600 mph over 50 to 100 miles (7,240 to 9,010 kilometers per hour over 80 to 161 kilometers). This is the advantage of railguns, very high bullet speeds. This gives the bullet a massive amount of energy.
The weapon works by basically smashing into something else, transferring most of that kinetic energy into whatever it hits which ultimately ends up as heat. This is the same reason brake pads on cars get hot, transfer of kinetic energy into heat.
When the projectile hits something and stops, the bullet and whatever it hits will get very hot. The projectile is probably made of metal which is in fact very flammable if you get enough oxygen to it. So there is a fireball, either because whatever it hits is flammable or because the projectile/whatever it hits is burning.
When you hit something that fast the behavior of metals changes. The speed of sound (see * below) in metal is high but if you hit something fast enough, then you can actually exceed the speed of sound in a metal and the rear of the projectile will carry on moving as though it hasn't hit anything when the front has hit something. This is the same idea of a shock-wave in air but it's in metal. Heres a good youtube video:
http://www.youtube.com/watch?v...
Well needless to say this tends to result in some funky stuff, like the metal bullet tearing it's self apart into lots of small pieces. This is a big driver in some anti-tank weaponry. If you hit the armour just right then you can actually get the inside of the tank to shatter, basically turning the inside of the tank into a shrapnel grenade, killing the operators.
If the projectile shatters then it's going to be hot and have a large surface area and you can get lots of oxygen to it which will result in a fireball, potentially it will burn about as hot as 1000 K. This to me seems like a good thing to design for because the added heat is going to do things like start fires and ignite conventional bullets/warheads and burn through armour.
* The speed of sound refers to the maximum speed at which a mechanical vibration (much like the pressure changes that cause sound. Not like light, RF, or electricity) can travel through a medium. Mach1 refers to that maximum speed of those wave's permeation through air, however different media such as water, metal, and glass will have different values for that maximum speed.
So, as the projectile hits some theoretical immovable object, the front will stop, but the rest will continue collapsing in on the front, faster than the pulse created on initial impact (a mechanical vibration that would otherwise influence the rear of the projectile to slow down) can travel to the rear of the projectile.
A bad, but visual representation of this is if you had a long line off cars driving down the freeway bumper to bumper. The first crashed and was brought to a halt instantaneously. In a normal crash each car behind would generally apply brakes and slow down before impact. However, for this example, everyone is driving faster than their own reaction time, so they are part of the pileup before they have registered an accident happened in the first place.
http://www.reddit.com/r/askscience/comments/22iqo3/why_does_the_us_navy_rail_gun_round_explode_into/
There are two other, very large factors - the cost (energy, fuel, time, human and other resources) of getting the ammunition and the propellant to the battle, and the safety. The fuel to drive the ammo supply ships has to be taken into account. A given ship is expected to be able to carry four times as many rounds of railgun ammunition vs. standard ammunition, eliminating two or three supply runs, and possibly dangerous deliveries between ships in the middle of the ocean. Ammo ships are notoriously bad duty in real wars, and if you look through WWII naval battles it is quite common for the killing blow to a ship having been penetration and detonation of one or more magazines.
From a _systems_ point of view (which is the Navy's POV on this), the cost of railguns will be much less. While at present manufacturing cost of the projectiles is high, it's already competitive with equivalent damage-producing shells. And passive solid tungsten projectiles could become quite cheap once the high precision high volume manufacturing gets in gear.
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So, what I wonder is how the railguns fit into this. It seems that they'd be prone to very effectively making a couple of small holes in whatever they hit and delivering most of the energy into the sea or ground. Unless you actually hit the engines or some other critical piece, a ship, especially a warship can survive a surprisingly large number of holes before it is put out of action.
I believe the primary potential advantage of railguns is that they allow for a higher number of rounds to be carried and potentially fired at a higher rate, and have the defensive aspect of removing a critical vulnerability aboard ship. Its a significant advantage if, as you imply, the enemy will have a hard time sinking you because you don't have a magazine to detonate.
On the subject of ammunition, railguns are probably less efficient in general, but its probably a lot easier to store more fuel and less intrinsically explosive ordinance. Its not just that your ammunition is smaller because it doesn't need propellant, its likely the lower safety requirements would allow you to store your rounds at a higher space density over all. Naval vessels that are already nuclear don't need to even worry about higher fuel requirements, but even diesel ships are probably easier to design as carrying more fuel than more ammunition.
Thinking about efficiency, I wonder how much conventional ammunition is destroyed when it is not used for a significant length of time? I would imagine naval artillery shells have a "best used by" date of some kind, and their propellant and/or warheads don't have infinite shelf stable lifetimes. A railgun bullet could last a lot longer without degrading, and if your propellant is fundamentally diesel fuel (indirectly converted to electricity) then your diesel fuel remains constantly refreshed whether you fire your weapons or not. In terms of energy density cordite might be more efficient than railgun power, but the actual logistics of having a single fuel and using electricity might be in the long run cheaper than building and periodically recycling old ammunition.