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World's Most Powerful Rail Gun Delivered to US Navy
An anonymous reader writes "The world's most powerful functional rail gun capable of accelerating projectiles up to Mach 8 has been delivered to the Navy. The new rail gun is a 32-megajoule Electro-Magnetic Laboratory Rail Gun. The Navy eventually hopes to have 64-megajoule ship mounted rail guns. 'The lab version doesn't look particularly menacing -- more like a long, belt-fed airport screening device than like a futuristic cannon -- but the system will fire rounds at up to Mach 8, drawing on tremendous amounts of electricity to generate the current for each test shot. That, of course, is the problem with rail guns: Like lasers, they're out of step with modern-day generators and capacitors. Eight and 9-megajoule rail guns have been fired before, but providing 3 million amps of power per shot has been a limitation.'"
An effective military rail gun would need a huge vessel to carry the capacitor bank and a nuclear power station to make a rail gun practical. Where is the Navy going to get something like that?
Oh wait...
"Prefiero morir de pie que vivir siempre arrodillado!"
The REAL reason Fusion power will be perfected...so the Generals can fire their fancy guns more than a few times an hour.
Amps of power?
Indeed. Amps = current Watts = power
Well, it's no Reason, but we're getting there.
Imagine a beowulf cluster of these!
Seriously, how much energy does it take to kill someone.
I noticed that almost every story today has this tag on it. What could possibly go wrong if you stop using this tag for every article?
Somehow the Navy must have stole them from the Air Force. I know that the Air Force has had rail gun for years. Of course whomever stole it forgot to steal the Naquidah generators that you need to feed the things.
These rail guns are pretty good at taking down a Wraith dart. Why would the Navy be worried about taking down Wraith darts?
Now I am worried.
Tsukasa: All I really want, is to be left alone...
They need to attach some focal confirmation for when you hit the target:
Headshot!
Let me know when the flux capacitors get fully charged...
Ask not what you can do for your country. Ask what your country did to you
So who'll be the first genius to fling a toilet bowl through it?
...when will we get Tesla Coils? :/
Three rings for the Elven-kings in the sky
There is no such thing as overkill. There is only "still firing" and "out of ammo."
In Xanadu did Kubla Khan
A stately pleasure dome decree
A spokesman for the Iranian Navy was reported as saying ..."Camping faggots!"
"I like to lick butts!" by MobileTatsu-NJG (#32700246) (Score:5, Informative)
It's also capable of propelling ships in reverse at speeds of up to Mach 3.
As far as I can tell- the article mentions nothing about the types of ammunition they fire with this- however upon closer inspection,
I may have found a clue:
"Installation of the laboratory launcher is currently under way"
Seems like a waste of some perfectly good laboratories!
....move along....nothing to see here....
and what colour trail did the Navy pick?
If my call is important, why am I talking to a recording?
God, this is why I love being an American.
Virginia is for lovers. EVE is for griefers.
No one needs more than a 64-megajoule rail gun.
Mach 8 is about 9800KPH. Escape velocity from the Earth's surface is 40,320KPH. This gun is already firing at over 24% of escape velocity. A 64Mj gun would be almost 50%; a 132Mj gun would shoot projectiles right into orbit.
I wonder whether coming generations of this gun could shoot unmanned exploration vehicles or satellites out into space. The Pentagon will probably try to use it just to shoot down spacecraft, but instead we could use their budgets to increase space industry and exploration.
--
make install -not war
As TFA points out, the Navy is planning to put one on the DDX destroyer, the smallest serious ship the Navy floats.
I hope that the Navy's new Rail Gun doesn't require a brief but critical period to charge before firing, and I hope that is does not require all non-essential power systems to be deactivated, leaving the ship powerless and adrift for a short time after firing... (wiki)
I wonder how many times this thing can be fired. They need to get 32 megajoules of energy out of the gun, and without the metal that this power passes through melting. That's not an easy thing to do.
Railguns today tend to melt after each shot, leaving one to replace the rails (the biggest, conducting the part of the gun, the bit in contact with the "bullet").
I wonder what the efficiency is. 32 megajoules come in, how many leave in the bullet. (Generally they only get about 2%-5% efficiency).
An alternative, easier and safer, is a coil gun. Here's a nice index of coilguns : World's coilgun arsenal. But like their railgun brothers, they're not very efficient. The very best of them have the bullet speed of a mini handgun, but they're trivial to make, and rely only on batteries and metal.
I don't know if World War III will be fought with railguns or belt-fed airport screening devices, but World War IV will be fought with sticks and stones.
There might be some cool theoretical replacements to explosive propellants, but it is difficult to see them being deployed meaningfully any time soon.
Engineering is the art of compromise.
a rail gun was way back when Paladian was making these rpg books, it was called Rifts. If I remember correctly, Glitterbots had rail guns.
We get a lot of cool technologies because the military wants new toys. You can argue about if it should be that way or not, but it is how things go. GPS is a great example. No civilian organization would invest in something that big. Are you crazy? Who would want that? However the cost wasn't a problem for the military and hence we got one of the most amazing navigational aids ever. Even now that the technology has been proven feasible and useful, or rather essential, the military run systems remains the only one. The European civilian governmental version remains snarled up in political battles.
So while you jest, there could be truth in the statement. Fusion is all well and fine, but there's only so much money going to be thrown at it. We have other cheap power sources in terms of commercial use, so not a lot of commercial dollars, and it just isn't sexy or pressing enough to get much government research dollars... However if there's a major military application, well that could get billions easily.
That's one reason I'm not always opposed to defense spending. Though it is very often wasteful and it seems there are better things to do with the money, it does seem to be one way for getting projects that just don't get built otherwise. A great many things come directly from defense research.
It's all fun and games until someone decides to make a nuclear-capable artillery shell for this thing. Missile defense? I don't think so.
[Sir Garlon] is the marvellest knight that is now living, for he destroyeth many good knights, for he goeth invisible.
How many amps are used doesn't give a good idea about how much power/energy this thing uses, besides using order of magnitude estimating.
I had a physics teacher who used to work at Los Alamos who did some consulting for the military on the side. In the late 80's/early 90's, they had him evaluate the results of some rail-gun tests. They were shooting a small ball projectile at tanks. The projectile left a perfectly round smooth bored hole all the way through the tank, wherever it was fired. The military wanted to know if they could use this to disable things (fire through the engine block) without destroying other things (people, electronics, paperwork, whatever) inside.
In evaluating it, they found that the internal air temperature flashed to something really high (like an oven) in the microsecond the ball travelled through, and that the vaporized steel from the first surface of the tank would kill everyone in the compartment.
It brings home what kind of speeds we're talking about here.
I'm waiting until they start listing the speeds of rail guns in terms of [decimal]c. Full of relativistic goodness. Of course, if they're only at Mach 8, they've got a way to go. The X-15 was near mach 7 and the scramjet tests have hit mach 10, and I'm sure those were more massive than the rail gun's projectiles.
Can anyone tell me how to set my sig on Slashdot?
let's get out there men and show those damn whales who the hell is in charge here!
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Are these things going to be turret-mounted like with battleships or will the rail have to be as long as the ship, requiring the whole vessel to turn to align the weapon?
Kwisatz Haderach
Sell the spice to CHOAM
This Mahdi took Shaddam's Throne
Some of the features:
Navy Fact File
As I recall, the original list of superweapons was much more impressive. It just got pared back a smidge when Congress balked at the price tag.
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That's the other tricky part. Someone will have to develop an onboard guidance system that can survive the awesome strain. Accomplish that and you will have a truly handy weapon. 200nm in a matter of minutes would be good enough to provide nice support for Marines ashore. It would be better than Tomahawk (albeit with a shorter range and no submunitions capability).
Since this weapon is out of my field, is it practical for anti-ship use? In theory, could you input the known location of an enemy battlegroup (plus a little predicted steaming time), fire some rounds downrange at the area, and then rely on onboard terminal guidance to hit the target? If so, you could replace Harpoon as well.
Heck, if they can make it work, they should develop small, less powerful versions for small boat and point defense. Wouldn't even need the onboard guidance at that point. Now you've replaced Tomahawk (maybe), Harpoon, Phalanx, and the Mk 38 gun. That would make the logistics tail a lot easier to handle.
Keep in mind the relationship between energy and power. Assuming the reactor on a ship can only produce a fixed amount of power there is a trade off between rate of fire and the kinetic energy of the projectile. If the user of said railgun charges the capacitor bank from a 15 amp wall outlet for five minutes the gun will be capable of firing a small projectile at a reasonably high rate of speed. But if the user charges it up over night it can fire a massive projectile at the same speed.
As far as getting the massive amount of power from the capacitor bank to the railgun itself, I am confident that the military has the capital to use some sort of superconducting material to deliver as much power as they need. I think it's likely more difficult to construct a physical "gun" that can handle the "reaction" from the projectile's "action." I suspect the Navy wants to fire very large projectiles at a very high rate of speed and isn't too concerned about how rapidly they fire them.
One of our competitors trademarked the term "hypothesis". From now on, we will call them "boneheaded ideas".
I think the jury is still out on whether rail guns or light gas guns will be the next step.
Let me list the current advantages/disadvantages:
Rail Gun:
+ Simple firing mechanism (Two rails, one plug, massive juice)
+Very little muzzle flash
+Very rapid fire (Gatling configuration to spread out heat on rails)
*Acceleration limited by current carrying capability of rails.
- Complex/heavy electrical system (Banks of caps + power supply to charge them)
- Rail wear
-Heavy projectiles increases support structure significantly
Light Gas Gun:
+ Heavy projectiles scales up rather well.
* Medium complexity (More complicated than Gatling mechanism)
* Acceleration limited by maximum chamber pressure.
- Bore wear
- HUMONGOUS muzzle flash (hydrogen combusting)
- Medium rate of fire.
Bottom line: Flechettes: Rail gun; Sub Orbital or ship killer: Light Gas Gun
Currently light gas guns emit a huge fireball out the end of them, which may tend to limit their use for a shoulder fired weapon (anti-tank, anti-air). On the other hand it is a lot easier to store and release obscene amounts of energy in a gas or powder than in electrical form. I would imagine porting the barrel would allow recovery of some of the hydrogen.
One advantage the railgun might have is it might allow different projectile shapes like fins that would be difficult to achieve with a light gas gun.
We should be using light gas guns to ship fuel up to the bottom of a chain of a LEO space elevators.
They ARE out to get you simply because They are in it for themselves and they don't care about you.
You are the biggest victims of FRAUD.
PatRIOTically,
Kilgore Trout
I for one welcome our alien overlords...to try and outrun this monstrosity. BFG, eat your heart out.
Especially if Enron was still around.
Of course that might just overflow a double int and they would get a refund every month.
"What does B49 do? It destroys everything but the fillings in their teeth and helps pay for the war effort." - Bill Hicks
"Trademarks are the heraldry of the new feudalism."
Maybe the terrorists will listen to Reason?
But seriously.. is this for fighting China? Why are we still preparing for WWII when we're already good to go for WWIII?
The Zumwalt class destroyer (aka DD(X)) destroyers are not "the smallest serious ship the Navy floats" unless you don't consider Ticonderoga and Arleigh Burke class ships to be serious ships.
At 15,000 tons of displacement, the Zumwalt class ships are pretty damn big.
A spokesperson for Iran Air was reported as wondering "Are these rail guns capable of shooting down civilian aircrafts too?"
Unfortunately you are a little off with your physics there. To double the velocity you must quadruple the energy. i.e a 128MJ rail gun would be almost 50% of escape velocity. However you can always reduce the mass of the projectile, as assuming the energy imparted remains the same, get closer to escape velocity.
There is still one other effect you have forgotten. The 11km/s escape velocity of the Earth assumes zero air resistance. If you manage to travel at 11km/s on the surface of the planet and you will find that you have a heating problem considerably worse than something like the space shuttle re-entry and this will slow you down pretty rapidly.
Ampere is a measure of current, not power.
To put it this way, the European Spallation Source is a planned particle accelerator which is planned to have a proton-beam current in the range of a few milli-ampere. That is, comparable to the current drawn by your LCD monitor in standby. The catch is that ESS will be using proton energies up to a billion electron volts, thus making the power output of the accelerator comparable to a small nuclear reactor.
You can NOT quote power in terms of ampere without specifying the voltage. Conversely I've generated several thousands of volts using my bare hands and a piece of nylon, but because the current was rather small nobody noticed.
What is even more interesting is the time over which you can sustain a given power output. Over at our physics department we have lasers with power outputs beyond all the worlds nuclear reactors taken together. The pulse doesn't last very long however...
Perhaps the twin towers would still be in New York if we had one of these guns mounted on the top of each tower on 9/11.
I'm sure a President like George Bush will only use these in a just war. Sleep well tonight friends.
An article a while ago had a plan for a circular track a few miles wide. The launch vehicle would be magnetically accelerated along the track and on the last trip around be diverted to a straight launch rail for that last bit of acceleration to target. It was still quite a few gees sideways going around, but a lot less than achieving orbital velocity in a short straight acceleration.
They will come up with an unlimited source for this energy. Apparently they never watched The Matrix...
Thats what I suspected.
On large ships, other kinds of weapons are preferable.
This will be more like a traditional gunboat, carrying only one primary gun. Also, as it says in the article, the recoil makes it unlikely that this gun will fire many shots in one battle.
I think this will be a bit like a naval sniper, aiming to destroy major vessels command center before its even detected, and then leave the area quickly and let the big ships take over.
So we won't see many ships with this configuration, but in certain situations, it could probably end a battle before it even gets started. That is, as we all know, the best way to win battles.
Rail guns have been around since the 1850's. http://en.wikipedia.org/wiki/Railroad_gun/
:P
Slashdot is too nerdy for me.
Eight and 9-megajoule rail guns have been fired before, but providing 3 million amps of power per shot has been a limitation.
I agree. This would be extremely hard to achieve since amp is a unit of current. The problem is not that but rather that in combination with the voltage required to drive it.
Surprised more people haven't commented on this. Ending a summary with "3 million amps of power" is a classic Slashdotism. It would once have provoked many responses pointing out that an amp of power makes as much sense as a gallon of distance. Perhaps we can't be bothered correcting the editors any more.
>north
You're an immobile computer, remember?
"I would be more concerned about windage and elevation targeting of a object 220 miles away with a project traveling at Mach 8. The angle of the gun and flight projectile would need to be carefully calaculated"
Last I heard railgun rounds fall into the category of precision guided munitions. I don't know the precise method, but I would assume a combination of GPS navigation and possibly laser illunination for the terminal phase if needed. So, the windage and elevation are a bit less of a concern except that the less "manuvering" a round would have to do, the more of it's kinetic energy would remain to be applied against the target.
You either believe in rational thought or you don't
Do you know where we can get some ZPM's to power it?
Just imagine a beowulf-minigun of these!
+1 Funny Signature
You're right, I forgot about the frigates. D'oh.
s/smallest/second smallest/g
The point being, of course, that it's hardly necessary to have an aircraft carrier to power a railgun, as the OP implied.
Not the railgun in the article but a lower power one with similar construction, and with an amazingly cool looking projectile. I know we're not in the habit of posting youtube vids, but I couldn't resist. http://youtube.com/watch?v=y54aLcC3G74
By the size of the bits of canvas left after they hit the tents.
Deleted
This is talking about retrieval of air craft. In other words, can we find a better way to stop a jet fighter that's at full thrust in case it misses the series of cables the tailhook is trying to snag.
Government's view of the economy: If it moves, tax it. If it keeps moving,regulate it. If it stops moving, subsidize it.
It seems that i ran across someone using a flywheel to store massive amounts of energy like this a while back. After doing a little math I found that a flywheel that was 3m in diameter, at a modest 3000 rpm, and weighing 500 Kg would have between ~30 and ~55 Mega joules of energy (depending on its inertia, ranging from disk to ring)
The editor who posted this was fragged with the BFG, but respawned this article a few days later.
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I sat next to one of the directors of the Navy's rail gun program, during a flight to Boston, and I had one of the most interesting talks with him. The projectiles fired experience about 30,000 g's of acceleration, compared with 12,000 g's for a conventional gun. The major problem is that about 20% of the g's are experienced laterally because the projectile bounce when it is traveling down the rails. The projectiles do not contain explosives, because the kinetic energy is enough to do some pretty good damage. The materials problem with the rails was solved a while ago, and they need to survive for about 1000 shots to be comparable to today's guns. They also don't store the energy for very long before firing, because of losses and safety.
Uhh, wouldn't that require a line of sight to the intended target? Naval combat within visual range went out of style after Coral Sea. If you don't need a LOS then it would seem to be that this is a guided projectile and you don't exactly need a railgun for that (see harpoon, exocet, etc, etc).
I would suspect that the Naval interest in rail-gun technology is probably aimed at point-defense (i.e: shooting down incoming anti-ship missiles) more then anything else.
I want peace on earth and goodwill toward man.
We are the United States Government! We don't do that sort of thing.
Uh, it's a ballistic weapon, and the ammunition is literally just a blob of metal (preferably heavy). It's not firing missles or any kind of guided munition - its job is to project extreme kinetic energy into a ship/bunker/building/etc, not to take out a moving car or other precise target.
The article says the railgun is expected to have a range of 220 miles.
Yeah, we made the Atomic bomb first....except that we didn't.
We had a controlled fission pile at University of Chicago well before the first bomb.
Even though Civilian power plants came after the bomb, controlled fission came first.
We are likley to see a controlled self-sustaining fusion reaction well before we see a pure fusion bomb.
A rail gun would be a very effective tool for destroying incoming ICBMs and whatnot.
Yeah, I got that part. What I mean is: I have no idea how an "advanced" arresting gear differs from a "regular" arresting gear. i.e. The navy isn't saying. It's just... advanced. :-P
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This is sort of remeniscent of a friend's RV, where in order to use the microwave, every other electrical system onboard had to be unplugged or shut off. I was told it was interesting sitting in the dark where the only light source was from the microwave.
Live forever, or die trying.
So it has to be a guided projectile then (no, I didn't RTFA ;)... which begs the question of what advantage will it actually have over a missile? Speed seems like a likely answer, but a missile system doesn't impose these types of requirements (power generation) on a host vessel....
I want peace on earth and goodwill toward man.
We are the United States Government! We don't do that sort of thing.
The main goal of these guns is to replace the Cruise Missile. A single cruise missile costs roughly 1 Million Dollars *evil maniacal laugh* (ahem). The costs for the rail gun is maybe $100 per projectile, tops. I'm including machining in this, the actual material costs are quite low. The rails themselves are somewhat more expensive, but the over all cost is still less than an equivalent amount of cruise missile.
Fly me to the moon Let me sing among those stars Let me see what spring is like On jupiter and mars
64 megajoules is enough for anybody.
Often, when things go pear-shaped, the first thing you want to do is light off everything you've got and turn the engines up to 11.
When you've got something off http://en.wikipedia.org/wiki/Air-to-surface_missile coming at you at Mach kiss-butt-goodbye, working the geometry to minimize your signature, unmask close-in weapons, and try to make the missile overshoot depends on maneuverability, and that's a function of water force against the rudders.
Now, if this can be used as an argument to fund more nuclear powered small boys...
(http://en.wikipedia.org/wiki/Rickover's corpse smiles at the thought)
Get thee glass eyes, and, like a scurvy politician, seem to see things thou dost not.--King Lear
These go to 11.
The opposite of progress is congress
Atlantis, Duh!
I would expect the lack of a million dollar pricetag per projectile would be the big thing.
A Pirate and a Puritan look the same on a balance sheet.
This is the second one now! Bastards keep giving it to the US Navy when it tries to cross the border. I'm not paying for anymore...
Increased range, far greater damage potential (because of the extremely high kinetic energies), smaller size of the projectile (because there is no explosive component), etc
It's not a guided projectile, because anything you'd strap to it probably couldn't withstand the high acceleration nor the extremely high electrical and magnetic fields in the launcher.
But if you have a computer to adjust firing angle, firing energy, etc, you can very well make it targeted (by doing the calculation required for it to strike a target XX miles away at XX altitude).
The troll with karma.
Actually a rain gun could be fire so that the object arcs in such a matter as to follow the curvature of the earth, but depending upon the material used I don't think that is a possibility, especially since the air would create so much resistance....
Dr. Stantz: You know, it just occurred to me that we really haven't had a successful test of this equipment.
Dr. Spengler: I blame myself.
Dr. Peter Venkman: So do I.
Dr. Stantz: Well, no sense in worrying about it now.
Dr. Peter Venkman: Why worry? Each one of us is carrying an unlicensed nuclear accelerator on his back.
Why, may I ask, must it (the projectile) be a guided one? If it is only for the range then I can assure you that it does not have to be a guided projectile. This of it as advanced artillery if you must. Just because it has a range greater than ~30 miles does not mean that it "has" to be a a guided projectile. All you really need is some good ol' Newton's equations of motion and a launcher powerful enough to rocket the projectile at the necessary velocity (mach 8) and you sure as hell can hit most any spot on planet earth you with with out the projectile being guided other than pointed along the correct vector.
But how will we defeat terrorists and insurgents who disguise themselves as civilians, hide in crowds, and attack in small numbers if we don't have a big-ass gun capable of punching a hole in the moon?
SJW: Someone who has run out of real oppression, and has to fake it.
Guided projectiles can be shot down or intercepted or confused with chaff or flares or electromagnetic interference. Unguided projectiles, by their very nature, are not subject to being interfered with--and at such high speeds, it's unlikely the target would be able to see it coming. It'd take 2.2 minutesish to go the 220 mile range, so while it may not be very easy to snipe a mobile target, shore emplacements and the like would be sitting ducks.
If I had such a boat, I would use it against shore batteries, harbor fuel tanks, and other such targets--unless it had some -really- good stealth on it, in which case a bit of close-in sniping might work.
In Xanadu did Kubla Khan
A stately pleasure dome decree
It's not a guided projectile.
It really is just a very very fast moving bullet. Well, shell. Big shell.
The kinetic energy in a block of metal moving at mach 8 is enough to give a pretty good impression of a powerful explosion if something (eg enemy ship) stops it.
It's also horrifically accurate for an unguided projectile weapon.
Well you could magnetize the tailhook and use electrical induction to slow the aircraft. But I somehow doubt that would work very well. More likely, they just found a better material for arresting cables or something.
In Repressive Burma, it's not just your connection that dies. slashdot.org/comments.pl?sid=314547&cid=20819199
nothing is going to stop a massive lump of metal doing mach 8.
If you mod me down, I will become more powerful than you can imagine....
Rail guns do not generate recoil in the same way that conventional guns do. Recoil in a railgun is perpendicular to the direction of the projectiles travel. It tends to force the rails apart which causes arcing, rail ablation and a drop in current.
You might want to read up on homopolar generators as a power source. Given that the Navy wants all future vessels to be driven by all electric propulsion, they must want power flexibility for some reason - powering energy weapons would be one use. I think the largest homopolar generator was capable of 500 mega-joules at enormous dc amperage which would be appropriate for a naval weapon.
Hmm... I'm thinking giant praying-mantis arms mounted on the prow of the ship with quick-release soft-landing foam. They reach out and catch the wings while filling the air with foam. That would be sweet.
i'd hit it so hard, if you pulled me out you'd be the king of britain [bash.org]
I would suspect that the Naval interest in rail-gun technology is probably aimed at point-defense (i.e: shooting down incoming anti-ship missiles) more then anything else.
The navy is well established on record at looking to use rail-guns to replace cannons. Rail guns provide much higher velocity (quicker to target) with corresponding higher kinetic energies and penetration capabilities. Round for round, rail rounds are much smaller. Of course, right now, the required energy systems more shift the round size advantage to the negative, but they hope to one day have that addressed as well.
Think about it, firing a round at say twice the range and half the travel time, which greater accuracy is certainly on every military man's wish list. And when you have a round which travels at speeds in excess of mach 5, for many categories of targets, an explosive round isn't even required.
advanced....hmmm better AG Engines, Not using steel cables, easier maintainability... http://www.globalsecurity.org/military/library/policy/navy/ntsp/ look for (Advanced Arresting Gear(AAG) [MS Word])
Pshhh, just tell congress to think of the _insert_ children/terrorists/pedophiles/global warming, and they'll quickly sign the check.
Might the Department of Defense's recent effort and research to develop a feasible, mobile solar power source be related? The idea was to beam solar light from space using satellites and focus it onto a solar grid of some sort.
:) (heh.. heh..)
I remember it being (potentially) 10 megawatts, which isn't quite enough to power these devices, but with enough R&D...
http://hardware.slashdot.org/article.pl?sid=07/10/14/2129233 http://blog.wired.com/defense/2007/06/post.html And there's always nuclear etc... I'm pretty sure they have a conceived way to power it if they've already gone this far with the plan.
Fact: Everything I say is fiction.
A rail gun projectile would have to endure much, much worse atmospheric heating than any reentry vehicle.
On reentry, the thin upper layers of the atmosphere are used to slow the vehicle down. By the time it reaches sea level, it's going pretty slow.
A ballistic projectile would have to be going considerably faster than orbital velocity at sea level in order to be anywhere near orbital velocity when it gets high enough to go into orbit.
No line-of-sight required, nor is any guided projectile. If you haven't noticed the US Navy doesn't fight other navies anymore. This could replace the role of battleships in shore bombardment, or send unguided kinetic weapons ashore.
A railgun, in tactical terms, is a gun. All guided weapons do is obviate the need to either drop bombs accurately (which is difficult) or aim the missile physically (in the case of cruise missiles). There's still a large role for ballistic weapons, even in these larger applications. A large copper ball traveling at very high rates of speed will do just as much damage as a slower-traveling explosive shell, and is cheaper to manufacture than a guidance system.
In Repressive Burma, it's not just your connection that dies. slashdot.org/comments.pl?sid=314547&cid=20819199
Sorry. A pet peeve of mine.
Ok, lets use monkeys then.
Error reading device 'Signature'. (A)bort, (R)etry, (F)ail?
Not exactly. There were a number of surface combats later, all withing visual range: Savo, Cape Esperance, the two halves of the Naval Battle of Guadalcanal (Battle of Friday the Thirteenth and the Capital Ship Action), Tassafaronga and Vela la Vela among others, but with few exceptions, they were all night actions. Samar, part of Leyte Gulf is about the only major daytime surface action I can think of from that period.
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Actually, the final version(s) of this weapon system are intended to replace Tomahawks -- the article even mentions this towards the end. The production ammunition for the railgun will be GPS-guided, perhaps with some nifty high-tech scheme, probably with something lower-tech, like fins deploying as late as possible in the fight. It'll be substantially more expensive than conventional shells, but still an order of magnitude cheaper than cruise missiles -- and at Mach 8, will give less warning and be harder to intercept.
I think the Navy isn't actually all that interested in this as a ship-to-ship weapon; they don't any intention of allowing hostile surface ships within its maximum range of the carrier, whose planes can easily engage three times further away.
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Batteries are optional. I've made a couple coilguns out of a christmas paper wrapping tube filled with welding rod (cut to different lengths so it's solidly packed at the bottom tapering to 50% fill or so at the top) with a big coil of magnet wire around the bottom, that's attached directly to 110V AC (with a relay in there to turn it on/off.) The drag is it only fires ring-shaped projectiles -- but boy do they fly. Some time it'd be nice to build one that launches spheres rather than toroids, but that seems to require a lot more work.
Nostalgia's not what it used to be.
All of the points by others responding to your question are valid. I would also add that the military has had an interest in high-velocity projectiles (including scram jets) so that mobile targets could be hit before the enemy has a chance to evacuate (such as mobile missle launchers).
I would suspect that the Naval interest in rail-gun technology is probably aimed at point-defense (i.e: shooting down incoming anti-ship missiles) more then anything else.
:(
Nope, the Navy is actually specifically looking at rail guns to serve much the same purpose as cruise missiles do today -- striking specific stationary targets from a great distance and with high accuracy.
Advantages of a rail gun over cruise missiles (imo):
1) Vastly lower cost per projectile -- a slug of metal vs a self-contained rocket-propelled flying machine.
2) Vastly reduced danger of secondary explosions because it's non-explosive ordinance.
3) Higher capacity because of (1) and they're also smaller and lighter than cruise missiles.
4) Much harder to shoot down, since cruise missiles fly relatively low and slow, while rail gun rounds would hit their target in minutes after firing at several times the speed of sound.
5) Much higher rate of fire. You can't just plug in GPS coordinates into a cruise missile and hit "go", each firing is a complicated and carefully planned mission unto itself since you must account for terrain, and I've read most missile destroyers are limited to a couple launches per day. A ballistic trajectory would make this much simpler, so the main limit is charging the capacitors and they estimate they could achieve a rate of fire of 1 every 6 minutes (according to TFA).
Disadvantages:
1) Much lower range -- 220m for the 64 MJ rail gun, around 700m for a Tomahawk.
2) The same force experienced by the projectile is experienced by the rails, so it tends to destroy itself.
3) For high precision some simple guidance would be required for the last leg of the journey, and yes this is a potential problem, but it's not like they need anything approaching the guidance in a missile.
4) Due to (2) and (3) doesn't actually exist in working form yet.
If they pan out, rail guns won't replace cruise missiles in the Navy's arsenal, but they will provide a very potent tool for similar missions.
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Let's see...40,000lb jet, 130knots (unit conversions and other math omitted)...should be about 80MJ. Every time you land a jet, you can use the rail gun, even with some efficiency losses.
Oh, yeah, someone please check my math.
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I thought that the Navy was getting away from the steam catapults and going to rail guns. Maybe this isn't an energy weapon application, after all.
Disclaimer: I lack the knowledge to have a legitimate informed opinion on this topic.
Ram Accellerators may be cheaper in terms of raw dollars, but I wonder how well they scale relative to Rail guns? Specifically, economies of scale for mass production, and for the mass per projectile.
Once the technology is figured out for Railguns, I suspect the primary cost will be the power generation. The projectiles themselves will probably be very cheap, and be easier to manufacture than those used by a Ram Accellerator. Essentially, it sounds like the complex part of the rail cannon will be the gun, and the complex part of the Ram accellerator will be the projectiles.
Artillery works better when you can get mass quantities of bullets on the cheap.
The power requirements do seem to be the primary problem for the Railguns at the moment though. Are there any known projects using ram accellerators?
END COMMUNICATION
It will be a guided projectile, but inexpensive due to lack of things like a propulsion system. GPS + some control surfaces are cheap in comparison.
Your suspicions seem wrong from what I've seen. "The railgun's 200 to 250 nautical-mile range will allow Navy ships to strike deep in enemy territory while staying out of reach of hostile forces."
http://www.fredericksburg.com/News/FLS/2007/012007/01172007/251373 article's title is "A missile punch at bullet prices."
In 2007, the US Navy demonstrated a railgun prototype. It used about 8 megajoules, but the full scale weapon is designed to use 64 megajoules. By way of comparison, current conventional naval 5-inch guns have the equivalent of 9 megajoules of muzzle energy. The full scale weapon will have a range of 200 to 250 nautical miles, as compared to less than 15 nautical miles for a 5-inch gun. The PR handout said the full scale weapon will have "the punch of a Tomahawk cruise missile", or be the equivalent of "hitting a target with a Ford Taurus at 380 mph." It will also travel the 200-250 nautical miles to the target in about six minutes, as opposed to 8 for a Tomahawk cruise missile. At the peak of its ballistic trajectory, the projectile will reach an altitude of 500,000 feet, or about 95 miles, actually exiting the Earth's atmosphere.
We shall see if these rosy predictions pan out.
9 Megajoules may be a lot of energy to release in one fast pulse, but it doesn't actually require all that much time or power to charge.
Naval ships have big powerful engines or reactors that are capable of putting out a lot of power. If a measly 100kW (a tiny amount of total energy, equivalent to a 134 horsepower engine) has been budgeted to charge it up between shots, it will take 90 seconds to charge, this is a while, but the power was small. Suppose they increase it by an order of magnitude to 1MW (a carrier can easily generate this, though it may be expensive to design the charging system), then it only takes 9 seconds.
There are a number of other tricks they can use to speed up firing time, such as storing lots of standby energy in battery or fuel cell banks, ready to be drawn quickly to charge up the rail gun. Batteries and fuel cells can't discharge fast enough to fire a rail gun, but they store more energy than capacitors, so they can charge the bank multiple times without increasing the load on the ship's generators at all.
I'm not sure I see the problem here, it is just a matter of proper power engineering. Since this will probably be replacing some of the standard munitions, generation capacity can be increased.
I imagine if a plane comes back loaded for bear and the flaps are not able to fully extended it's a bit tricky to stop a half billion dollars of plane and weapons without ripping the pilots retinas out of his eyes and that's where the advanced part comes in.
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In the Soviet Navy, Advanced Arresting Gear hooks you.
"He Who Dares Wins"
You're thinking too big... Crazy glue, a few bungee cords, and three strips of duct tape measuring one point 4 inches by 20 meters. I'd tell you what they'll do with all that, but it's classified.
Government's view of the economy: If it moves, tax it. If it keeps moving,regulate it. If it stops moving, subsidize it.
As for the: "Advanced arresting gear" The Navy Fact File reference you provide states: "Electromagnetic Catapults and Advanced Arresting Gear that support future airwing configurations including unmanned air vehicles." - which suggests that the Navy is looking for better ways to land aircraft on their ships. Perhaps with shorter landing strips, better tennis nets, and perhaps some quick way of getting the 'planes out of the way so that the next 'plane can land.
The Navy might start considering my 22 ft wooden hull ZODIAC to be a "serious ship" if I could only mount a 64-megajoule Electro-Magnetic Rail Gun on it (with some decent bats, of course)!
"He Who Dares Wins"
BFG whores beware!
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The projo is going to be traveling in excess of Mach 8, I don't know how many G's it would take going from zero to Mach 8 in the length of a gun barrel, I'd guess 10K G's would be in the ballpark and that's out of the survivability range of any guidance package I can think of. After that any aerodynamic control surfaces would need a whole shit load of power to actuate in that kind of wind loads and again that wouldn't live through launch either. Not to mention when your projo is going that fast what's going to change? A discarding sabot Tank round goes about Mach 3 or 3600 MPH or a mile a sec so there isn't too much time between shot and splash for guidance to make any difference. This is the Navy, they have Gravity maps and Ocean Height maps so they even know if they have to aim a quarter inch high
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I'll start by confessing an ignorance of advanced projectile arc behavior, when it comes to an arc so long that it would have to conceivably 'bend around' the curvature of the earth to hit your target. But it occurs to me that it might be possible to fire an unguided ballistic without requiring line of sight (basically, a very short "low earth orbit" for lack of a better way to describe it).
.7 Mach vertical velocity coming out of the gun, if I've got my formulas correct, which would have the projectile in the air for a very long time if the earth were flat).
We're actually covering projectile motion in my physics class right now, and at least in the 'simple' model (where you aren't worried about the curvature of the earth), you have a great degree of flexibility in picking a trajectory to hit a target. The main constraint is figuring out how much 'air time' you have (based on the initial vertical velocity component of the trajectory), and choosing the correct horizontal velocity component so that your projectile has covered the correct distance in the time that the ballistic is in the air (assuming you have a great degree of control over the velocity at which the ballistic leaves your 'gun').
Now, it seems to me that if you have a gun that can fire a ballistic at Mach 8, and you choose a relatively 'flat' trajectory, the projectile would go so fast that before it fell into the sea, the sea would actually 'fall away' under it because of the curvature of the earth - like I said, almost a low-earth orbit, where the effect of gravity causes the projectile to wrap around the curvature of the earth.
So, do you *really* need line of sight for one of these railguns? I don't know how fast something would have to move to cover the distance to the horizon before gravity causes it to go 'plunk' in the sea, but Mach 8 sounds pretty darn fast (at that speed, even a very small amount of elevation on the trajectory, like 5 degrees, would give it a very 'high' arc to begin with - Mach 8 Sin 5deg ~=
That said, shooting down enemy missles could certainly be another use of this - but doesn't the Navy already have pretty effective anti-missle defenses (flak guns, lasers, stuff like that)?
Newton's third law is not correct for magnetic force. Momentum is conserved but some of it goes into the fields so rail guns do not recoil.
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They switch the rail guns to "attract". You fly overhead and they pluck you from the sky.
No sig today...
Sure something can stop a mach 8 flying lump of metal.
The ship/person/building you intend on pointing it at. Everyone knows that silly.
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anyone else make that mistake?.
Were they expecting a railgun and got a bobcat instead?
If that's the case what's the navy doing purchasing from (xkc)dBay?
bother, bother.
I could blow up the whole goddamn world with this thing...
If you combine a mach 8 ballistic projectile with a satellite-eye view of the combat theatre, over-the-horizon targeting becomes practical, just like it is with land based cannon. Some of the early computer work in WWII was exactly those sorts of extreme-range, indirect fire, artillery calculations. Previously it was only practical against stationary emplacements.
With developments like this however, modern computing power, satellite detection and ranging (SADAR?), and projectiles moving almost two miles/second could combine to make over-the-horizon ballistic targeting between moving subjects viable.
Metalll.. Geearrr?
I'm no railgun expert but if they are using magnetic fields to propel the projectile, there is an expanding field which pushes the object and that field is moved down the rail with the object. Isn't there then a collapsing field they are letting go to waste? I guess there would need to be some kind of switch/conductor which would allow the expanding field to be free to expand but when the field starts collapsing, the switch/conductor becomes a generator. Throwing that generated energy back into the system reduces the total energy required.
It's so obvious that they must already be doing this but I just figure I'd throw it out there anyway.
LoB
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Yes, you need to be maneuverable if you're in a short-range fight, but this isn't the kind of weapon you use to fight against kamikaze Zodiacs or nearby Soviet ships. But it's presumably not the only weapon you'd put on a ship this size; you'd keep smaller guns or torpedoes or whatever around for occasions when somebody objects to you using long-range artillery.
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Missiles have to carry their propulsion units and fuel with them, adding to projectile weight, cost and complexity, and don't go anywhere near mach 8 (most aren't even supersonic). The value of the speed of railgun projeciles against high value land targets in advance of Marines is mentioned in the article, so they must be guided in some way.
The rail guns aren't going to be used for something as mundane as point defense when there is already a very capable system for that. No, rail guns are going to be used for an age old problem of how to destroy something from a long ways away.
Pure and simple ordinance delivery is the problem these rail guns will solve.
Let's see...take a chunk of metal, shoot it at mach 6 and have it strike the earth 200 miles away. Add a little satellite guidance and next thing you know you are making a large deep crater exactly where you want it. Not to mention you are firing these guys 10 times a minute out of the gun.
Think of these as modern day battleships, except without the need for the VW sized powder bag or the 16" shell.
You're close, but you forgot to divide by 2. (KE = 1/2 mv^2) So, once shot every 2 flights.
nothing is going to stop a massive lump of metal doing mach 8.
You doubt the power of Chuck Norris?
I would suspect that the Naval interest in rail-gun technology is probably aimed at point-defense (i.e: shooting down incoming anti-ship missiles) more then anything else.
Sorry, no. The railgun system involves charging up a bank of capacitors, then firing off a projectile; point-defense systems tend to involve throwing a lot of bullets at the incoming.
The Navy's interest in railguns makes perfect sense. A missile is a complicated thing; you use it up when you fire it, so you can't test it much before you use it, and you need to fill it with fuel and such. The railgun lets you just shoot a big heavy projectile; it moves almost all of the cost into the reusable railgun, and the warheads are fairly cheap.
I read an article on the DDX ships and it said the warheads have little steering fins and guidance packages. You need that because over the course of 200 miles, any random buffeting from wind will throw the warhead off target. If you have a good fix on a target, you should be able to shoot it without line of sight (ballistic trajectory); just enter the map coordinates and the warhead goes there.
Finally, if the enemy gets a missile into your storage for missile fuel or explosive warheads, you are having a bad day. But if your ammo is just a bunch of inert warheads that don't do anything unless you shoot them from a railgun, you aren't having such a bad day. In other words the railgun warheads are safer for the sailors and ships than missiles.
Just a shame they test it in Scotland then - with lots of lovely depleted uranium. Aye, it's braw stuff. http://news.bbc.co.uk/1/hi/scotland/3148853.stm
Let us rewind:
And may, I draw you attention to this http://www.dtic.mil/ndia/2004armaments/DayII/SessionI/01_Cilli_EM_Gun.pdf. Slides 12/13 are particularly interesting... ("use their test facility at no cost to US")
Even "second smallest" is way off.
The DD(X) is bigger then some navies aircraft carriers. I'm not sure you realize how big these ships are compared to almost every combat ship out there. The only things that out-mass them by a significant margin are some aircraft carriers, the Kirov class battlecruisers, and some amphibous assualt craft. These "Destroyers" are bigger then most of the "Cruisers" out there.
Possibly the use of magnetic damping in the arresting gear cable spools. By varying the magnetic coupling between the spools and the hull you could achieve frictionless braking.
this might give new meaning to the phrase "Shoot the Moon"
Does it bother anybody else that after 4 genereations of Westinghouse reactors, The navy are switching to BECHTEL reactors?
Size.
In other words, this thing can shoot well over the horizon. All you need is a spotter (and we have those in orbit now, check Google Earth if you don't believe me :) ) and a good targeting computer.
Uhh, wouldn't that require a line of sight to the intended target?
That's what unmanned reconnaissance drones are for.
SB
It's old. The more humans I meet, the more I like my cats. At least they are honest.
hmmm, even better, have the inductance coils dump their energy into the railgun capacitors. That would give more energy.
Actually, the general idea is over-the-horizon shelling of ground locations. You can calculate, just like regular artillery, the trajectories just fine, and the cost per shot would be much cheaper than missiles, and in the case of the 64 Megajoule one, allow much larger payloads to be delivered to the target.
This is for shelling the crap out of installations or cities or what have you from farther away, bringing the battleship concept back into the realm of possibility.
You nuke 'em all from orbit. It's the only way to be sure.
SB
It's old. The more humans I meet, the more I like my cats. At least they are honest.
That's pretty neat and it's nice to have a wide-range of response options.
It'd sure be nice if we had better targeting tech though, hitting things from 220 miles away isn't that useful unless you're hitting the right things. For example, hitting an insurgent in a city full of civilians? Then there's the even trickier part of only hitting the right thing and nothing else. Then there's the problem of hitting the right thing, nothing else, and doing it affordably. Killing 2 madrasa-educated extremists equipped with rags and AKs by using multi-million dollar munitions seems like a Phyrric victory.
The railgun is impressive like many other tools in a nation's arsenal of big boomy-ness, but we're at the point where we'd lose a war fought with any nation that required the use of such weaponry. Everybody involved would lose that war. The world is still an unfriendly place of course, and there will be threats that require a just military response. It seems like focusing on expanding our abilities in small localized confrontations makes for a more useful "stick" to wield.
I hear they are using 32 Megajoules for the rail gun, and another 32 Megajoules for a rail speaker to blast "Impressive!!"
And that's why I love being an American, we can get other people to foot our bills when we're testing deadly and toxic weapons!
>Like one authorized by Congress, including Clinton and Edwards? What's your point? Bush led us into an unjust war and Clinton and Edwards agreed. Let's vote them all out of office. Unjust is unjust whether it comes from Republicans or Democrats.
I would like to point out that M1A1 Abrams tanks even have a laser that measures the droop of the gun. These guys are in the profession of arms, they know what they are doing and all I know is it is very impressive.
"providing 3 million amps of power per shot has been a limitation."
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I don't have a link to the article, but from what I recall reading about Naval rail guns the primary advantages are 1. cost (CHEAP projectiles, rather than millions for a single cruise missile) and 2. speed - your typical cruise missile doesn't get anywhere near mach 8.
Train-mounted hyper-oversized gun ?
According to TFA, that's actually what the US army is planning, except that, instead of a train, they plan to mount their oversized rail-gun on a ship.
Because of better mobility and also because the US already have electric ships with several-dozens-of-megawatt generators onboard that would be required to power the beast.
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I hear the nuclear reactor has a power level that is OVER 9000!
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True, current != power.
However, their problem isn't the amount of power, but the amount of current. Because current determines how fat the power leads need to be.
Actually, you could probably do it through a reconnaissance satellite and GPS. The recon satellite gives you the coordinates; you aim the gun like artillery, and you use GPS guidance to correct the shell's trajectory in-flight.
!#@%*)anks for hanging up the phone, dear.
More likely, they just found a better material for arresting cables or something.
But that can just be hooked up to existing carriers. I think that it's probably along the lines of the electric catapult - the hook/cable might not be magnetized, but the rail the cable's hooked to could be set up as a induction brake. A steadier stop would reduce wear and tear.
I don't read AC A human right
Don't forget Leyte Gulf, American carriers came under bombardment by the Yamato in that battle. American destroyers got within spitting range of the Japanese surface units.
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They are designing some big guns there, but they really do not fire all that often. So, is there a way to design some rail guns that will only go say 10-20 miles, but fire as rapid or more so than any gun we currently have? That would be handy. Of course, I would hate to see any of these capacitors be fully charged and hit with a charge. Probably as explosive as any other set of rounds.
I prefer the "u" in honour as it seems to be missing these days.
IIRC, the rail guns are to be used as a ballistic shell. Shooting a rod in a high trajectory with the impact being kinetically derived from its descent. Being hit by what is essentially a aerodynamic crowbar travelling several time the speed of sound can not feel good. Anyways the point being is you have a projectile that does large pin-point damage, is difficult if not impossible to detect/counter and most importantly is extremely cheap to fire. It would be well used for bunker busting and first strike/stealth attacks.
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Nope. You don't need line of sight to hit with an unguided projectile.
Big rail guns aren't useful for point defense. They're useful for putting a big lump of mass on target. Missiles, at least non-ballistic ones, are fairly easy to shoot down because they're slow. A rail gun projectile is fast, like ballistic missile fast, and even if you could hit it, it's just a big lump of metal so blowing it up really isn't all that effective.
CategoryArleigh BurkeKing George V>
Displacement9000 tons23,400 tons
Length509 feet598 feet
Beam60 feet89 feet
Propulsion100,000shp31,000shp
Crew320/td>870
So, the Arleigh Burke is nearly as long, has three times the engine power as a World War I era top of the line British Battleship. In terms of firepower, there's really no comparison. If you plopped an Alreigh Burke and a KGV into the same ocean, the Burke is going to have missiles away before the KGV can even make visual contact.
The moral of the story is that you really have to think about what the Navy has evolved into. It's not that there are no more battleships, per se, it is more like every combatant the navy has is a capital ship in its own right.
I must also digress about armor. It's also a bit of a gap to say that American ships aren't armoured. Yes, it is true that American warships do not have thick steel armour belts in the past, but its also true that thick armour belts can't resist modern shaped charges, its also true that they only were really thick at areas of a ship where designers anticipated the firing arcs of other shells would be. Have a look at the now declassified maps of the USS New Jersey's armor belts. You could theoretically program missiles to hit other parts of the ship. Against a range of threats, from bombs to torpedos, or even missiles that can be programmed to hit a ship from any angle, it is simply impossible to provide passive armor protection on all surfaces.
So, what designers do do is local armoring. They might not armour the entire hull, but they'll wrap critical equipment with some kevlar jackets, and that's not too shabby. That does come from combat experience, in a weird way. During vietnam, they did nothing to protect combat aircraft, but, they realized that putting a little bit of armor around a few critical things would save a lot of planes. These things were incorporated, among other things, into the highly successful A-10, which is a very survivable plane, and, to some extent, that sort of thinking has found itself into US Navy ships as well.
This is my sig.
How do you stop a plane when it hits the deck? You arrest it. really.
Use a holopolar generator. Big disks of copper inside a big field coil design to break it from a gazillion rpms to 0 in a millisecond. They have done this at the J. Pickle Research Center in Austin, Texas (A DOE project with your tax dollars, working on a fusion generator call Ignitex).
the problem is the stress on the copper declarating so fast can make it explode in a shower of molten metal. A really bad day if you are too close.
Sorry about the gazillion - I do not realize the actual details. I leave it as an exercise for the students.
Uh...
...
A railgun can shoot a projectile in a ballistic curve just like artillery
Now all we need is that damn ZPM! Well, maybe 3 of em....
Oh but you're wrong. Something most certainly WILL stop it. Preferably the innards of an enemy ship/plane/bunker/missle/etc. In a pinch the ground or ocean will do well enough too.
My only thought is how far does the projectile travel before it drops significantly in speed from air friction. Since air friction increases at the cube of speed i'd imagine there are some diminishing returns on moderate to long range projectiles. Your mach 8+ high-lethality envelope might be...10 or 20 miles (i'm not about to do the math).
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(yes, I RTFA'd this, for a change...)
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Nobody seems able to think of the obvious target set:
Satellites, aircraft, incoming missiles
Any ballistic device with a range of 220 miles horizontal will be able to reach 100 miles vertical.
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But when you're firing a Mach 10+ round... line of sight isn't much of an issue. You can fire beyond the horizon. Certainly not on par with a cruise missile, but still some serious range up to 300 miles.
Not to mention maintaining a missile is one thing, maintaining a graphite stick quite another all together.
Of course the technology isn't there yet but if it could manage to fire 30 rounds in an engagement at 300 miles with the same impact energy as the warhead of a conventional anti-ship missile you've got a real challenger.
Other advantages in the future: As laser weapons become feasible shooting down missiles will become simpler and simpler. With no warhead to ignite and no need to be 'airworthy' I would speculate that a railgun round would be dramatically more difficult to knock out of the sky than a cruise missile travelling at relatively low speeds.
I saw a TV program that mentioned guided tank rounds, and they mentioned they were withstanding ~6000 Gs. So challenging, but not impossible.
What? No.
1 word: Trajectory.
Do you realize how fast these travel? For a fraction of the (per shot) cost, you can send the same destructive power as a cruise missile the same distance, only instead of 1, it's 10 at a time.
Throw in some minimal guidance in to the slug and you can aim it from space.
The electron volt (eV) is a unit of energy (like joule) while the volt (V) measures the electric potential difference.
I wonder if anyone has thought about the effect all the magnets/electro magnetic fields will have on the fighters taking off and landing? I mean it would really suck to find the navigation memory scrambled and rebooting on take off when the plane is using the autopilot. I don't think many jets do manual takeoffs from a carrier anymore.
Also, I have hear things about pulsating magnetic fields doing strange things like welding metals together and creating heat energy in metals and causing sparks. It would probably suck even more to find a spark igniting some piece of magnesium or causing some weapons to detonate while staging for take off of that the missiles welded themselves to the mount and burn a hole in the fighter when attempting to dog fight.
Of course I might just have an over active imagination. I hope the military does too and already checked for these things.
Will someone please get their units straight? The small capacitors next to my CPU easily do three million amps per second, so what's difficult about 3 million amps per shot?
My CPU goes from say 10A to 100A in a few nanoseconds when it wakes up from sleep. This is 90 amps per "few" nanoseconds, or on the order of 10 billion amps per second (I canceled out 9 versus "a few"). That's 3000 times more than 3 million amps per second.
32 megajoule is not that much either. A typical airliner engine delivers that amount of energy every second. They mount a couple of those on a battleship for "emergency power" anyway.
So, with such a gun, you can shoot 2 or three rounds per second when powered by a gas turbine. Problem is that the army guys are probably aiming for more like 10 times that.
I don't understand why they are dicking around with railguns when coilguns (Gauss rifle) would make a lot more sense? Coil guns could potentialy fire a much larger projectile and require less maintenance. There is a difference in projectile speed but that can be overcome by using multistage devices with more finely made coils. If I can build one (low powered as it is, 3ft of range with a small ball bearing ) out of a disposable camera, wire and super glue, then the US goverment should be able to make one that could fire a bowling ball sized projectile 20 miles!
Clearly this is going to be used as a mobile TMD, for defensive purposes.
(Although you may already know that metal gear is nothing more than a nuclear equipped walking death-mobile)
What is the precision in meter (or yard if you prefer) of such a projectile launched in normal atmospheric condition (wind up to 10 mph) at the maximum range of 200 miles ? And compared to the blast radius ?
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Does it have Linux onboard? If it's not ran by Linux I don't want it.
Python is nice quick and flexible... but it provides so much rope a monkey would hang the whole ecosystem with it. -- in
He was trying not to be irrational.
Badum, chsssh.
Probably because one of the grandparent posters above talks about "sniping" a target vessel's bridge from 200 miles away with the first shot. When naval battles were last fought with big guns, no ship expected to score a hit with its first salvo unless the range was very short. Here are a few things I can think of:
So even if the weapon system is very, very accurate, that doesn't necessarily mean that it'll score a high percentage of hits. You could forgo the age-old and slow process of firing ranging shots and instead blaze away with rapid fire; dumb, solid projectiles are very cheap after all. Perhaps this is how they intend to use the weapon, but first they need to work out how to make rail-guns that can fire more than five shots before wearing out.
If the targets are ground-based and static, quite a few of the issues I've mentioned do seem to disappear.
I say we take-off and slashdot the site from orbit... it's the only way to be sure
Shakrai, I'm not sure you understand how the Railgun works. From the article: "The Marines, in particular, are interested in the potential for rail guns to deliver supporting fire from up to 220 miles away -- around 10 times further than standard ship-mounted cannons -- with rounds landing more quickly and with less advance warning than a volley of Tomahawk cruise missiles."
220 miles! That is not line of site. On the open ocean your line of site is really only a few miles. For example if you were to stand on top of the USS Enterprise you could see just a little over 20 miles, thats still 200 short of what the weapon will fire upon. For comparison the big bad ass cannons on the side of a WWII Battleship http://en.wikipedia.org/wiki/16%22/50_caliber_Mark_7_gun will fire about 20 miles, as far as we know.
Think of the weapon this way it is a small, hard to shoot down, really fast, really long range unguided projectile that will melt faces and sink your battleship.
Although you do raise an interesting point in point-defense technology. The rail gun can be adapted for long range assault and smaller faster versions for final defense measures like the R2D2 CIWS, http://en.wikipedia.org/wiki/Phalanx_CIWS is currently being used for.
...it'll be completely useless if you're lagging.
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We were somewhere around Barstow on the edge of the desert when the drugs began to take hold. - HST
the equivalent of "hitting a target with a Ford Taurus at 380 mph."
Even by slashdot standards, that is a truly spectacular car analogy.
Good job we can all visualise that sort of collision O_o
3 million amps of power? Too bad.
It should be 3 million amps of current, but at what voltage and for how long?
P = V*I
P = Power (in Watts)
V = Voltage (in Volts)
I = Current (in Amperes)
t = time duration (in seconds)
From the article, firing it six times a minute will require 8 MW of power. So, that's around 1.33 MW per fire, which would mean a supply voltage of 1.33/3 V?? (if I assume that the 3 million amps of power is drawn for the entire duration) This is a consummately fscked up calculation.
Planes touch down on an aircraft carrier and put their engines at full throttle - the idea is, if you've lost the third and fourth arresting cables (the third is normally engaged), you have enough speed to fly off (instead of swimming off)
Why do you feel ring-shaped projectiles are a problem? The mighty Wikipedia teaches us that one can easily build toroidal projectiles that are stable in supersonic flight.
Something bad is coming when people are suddenly anxious to tell the truth.
How do you have a projectile with a 200+ mile range that isn't guided?
Even at Mach 8 there's almost a two minute flight time to reach 200 miles. Ignoring wind, the coriolis effect and everything else that could change the course of your projectile, what happens if the target changes course in that time or takes evasive action? A lot can happen in two minutes.....
I want peace on earth and goodwill toward man.
We are the United States Government! We don't do that sort of thing.
He had claimed that he could reach Mach 2, and send a two ton projectile 90-miles, see http://query.nytimes.com/gst/abstract.html?res=9906E0DF1330E733A2575BC0A9639C946397D6CF
A little more on Birkeland's electromagnetic cannon can be found here: http://www.plasma-universe.com/index.php/Kristian_Birkeland#Electromagnetic_cannon
Ian Tresman plasma-universe.com
Point taken, but all of the surface actions in the Pacific during WW2 can be attributed to sheer necessity (either nighttime or a lack of carrier forces in the area) or stupidity (Halsey taking Ozawa's bait and leaving the Taffy groups exposed off Samar). The bulk of the decisive actions involved air power. Hell, air power was even the reason why half of those surface actions you cited happened -- most of the battles around Guadalcanal happened because the Japanese were forced to send in surface forces at night because of American dominance of the skies during the day.
In any event, I was responding to the idea that a rail gun would be useful for "sniping" at opposing warships and then "retreating" before they could respond. I would assume that this will mostly be useful for shore bombardment and maybe point defense (smaller rail-gun projectiles could replace/supplement existing CIWS systems). Ships and aircraft can take evasive action so this won't be very useful against them unless the projectiles are guided somehow.
I want peace on earth and goodwill toward man.
We are the United States Government! We don't do that sort of thing.
Yeah, they achieved that level at least 100 years ago last thursday. (finished that for ya)
I'd say you might want to go with a least a 5/8" thick hull. And maybe some heavy duty mounts. Standard drywall screws probably won't do the trick... And to really sell the idea, include a sub-detection unit and a good, quiet propulsion system.
This sig isn't original enough, it's time to come up with something witty...
After seven years, I think we're all pretty used to the current administration's tendencies towards cronyism.
Sigs are for losers
Advanced arresting gear (no idea what that means)
What happens when you use an electromagnetic catapult (linear motor, basically) backwards? You get a linear decelerator. What if you have two linear decelerators and each is attached to the end of a cable spanning the flight deck? You can control and steer the landing plane by analyzing forces. I know there has been some work to develop this since I've seen it first-hand, but I can't say for certain if this is what they mean by "advanced arresting gear". Plans may have changed.
Dewey, you fool! Your decimal system has played right into my hands!
1. Military hardware is EMP shielded. This is to prevent enemies from taking out our multi-trillion dollar war infrastructure with a simple electronic overload.
2. Autopilot? Off the deck of a carrier? That's not the Spartan way, that's just madness!
I don't think any jets do manual takeoffs from a carrier. (Unless you count VTOL craft like the Harrier Jumpjet.) The fighters are always launched to force them to clear the deck at takeoff speed. Planes that are too large for the launchers will tend to use JATO rockets to gain enough velocity by the end of the runway. Here's an image of modern carrier launch and recovery operations. It's dicey business WITH two operational catapults and arresting wires. As a result, not many pilots are willing to attempt an unlaunched flight off the deck of a carrier. Take a helicopter or a boat instead.
Lord help whoever mounts flammable magnesium on the deck of an aircraft carrier. The Admirals would make his head roll so far he'd make a trip to Pluto and back just so the Admirals could kick it again!
When magnesium is used as a construction material, it's almost always alloyed with other metals to prevent this exact problem. The alloy reduces the ignition point to ranges where you're actually more concerned about aluminum combustion.
Weapons on deck are treated VERY carefully. All ordinance on-deck have safety pins in them that must be removed just before takeoff. This is to prevent accidental detonation. Ordinance is also hardened a bit to withstand the rigors of combat flight as well as enemy countermeasures. (Nothing like your $10 million missile falling for a quick chaff.)
The hardpoints and ejector racks used on today's planes are unlikely to be susceptible to suddenly welding themselves in place. (Assuming that they're even close enough to the deck to worry about an accidental arc-weld.) Future Naval aircraft (e.g. F-35) will carry their primary ordinance inside an internal weapons bay, further reducing the exposure to accidental arcs.
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Mine are nowhere *near* supersonic and are comparatively unstable in flight. Even if they weren't, the idea projectile shape for drag reduction is basically like a Zeppelin, definitely not a toroid. Unfortunately, this design relies on a toroid as the shorted secondary winding of a linear motor, basically, so I'm stuck with it.
That's okay: it'll still go through a sheet of drywall.
Nostalgia's not what it used to be.
Well, crap. There was a transcription error between my paper scribbles and my kepboard during the number crunching. At least the error is in keeping with the inherited subject line.
Language students: Don't try to learn English here. This ain't it.
Point defense?! Are you kidding?!
You don't need a railgun for point defense. Current system work well and can be improved upon with better sensors, servos, and computers. Railguns are like non-radioactive nukes. Do you realize what 32 megajoules of kinetic energy would do at impact? It doesn't take much to knock down a missile. Disrupt its exhaust, put a bullet through its guidance system and it's pretty much taken care of. 8 megajoules is enough to liquefy a building. 32 is more like taking out a block.
Skiffy is Spiffy, but Ort is tort.
A slug moving at mach 5 can't be engaged by defense air missiles (shoulder fired or static) - other missiles can be engaged with some hope of success. Even a battleships' shells can't be engaged by defense air missiles.
If you can spot/detect a descending railgun slug at 20 km, the time for engagement is less than 20 seconds.
Guided shells from railguns can hit the backside (hidden side) of hills/mountains.
If your destroyer gets a hit in the magazine, nothing happens. By contrast, a hit in the magazine of a conventional guns bearing destroyer will pulverize it (more or less) due to the explosion of its own ordnance.
You can pump fuel easier and faster than filling the magazines with shells or missiles, and nobody cares if a thousands gallons of fuel are dumped to sea during refueling.
If all your power is electric, with the capacity for sudden changes, all that a railgun needs are some capacitors. While the capacitors are loaded, a hit against them would probably be important (if not fatal). Yet, while discharged, they shouldn't pose much of a risk if hit.
Electricity might be used for some things like laser close range defense systems - they might work better than the Phalanx, or at least could engage from a longer range - depending on visibility
In the end, if you launch lots of $1000 railgun shells, it's cheaper than cruise missiles. It might even be comparable per shot (energy delivered against the target) with the big guns, but with 5 times or more the range.
http://en.wikipedia.org/wiki/Arresting_gear
its basically turns it into an air craft carrier
I bet an equally-massive lump of metal doing mach 9 would do the trick
WE CANNOT AFFORD TO LOSE THE RAILGUN WAR! quickly, we must develop one that goes to 11!
... still waiting for this free-as-in-beer free beer I keep hearing about.
> For comparison the big bad ass cannons on the side of a WWII Battleship
Umm, they were on the centerline, facing fore and aft except in actual use. You are thinking of the 5 inchers, used for close-in shore bombardment, which did line the sides between the AA guns.
As long as ONE nation has super weapons, no other nation can POSSIBLY feel non-threatened. Doesn't matter whether the US actually USES them. It's their existence and actual deployment that is unnerving to some nations. And, it only justifies nations spending exorbitant sums of public money on otherwise phantom or unjustified war footing.
Yep. And guess what happens after that? The US acquires more power in the world and the "threatened" nation knows it can't step too far out of line or it risks war. Of course, the lesser powered nation will spend significant resources trying to defend against the new threat -- which is exactly what we (the US) want them to do. You see, warfare is a broader subject than just bullets and guns. It's also about the economics. Over time, if you can bankrupt your foes, then you might not even have to fight. And even if you can't, it's to your benefit that they spend significant resources chasing rainbows.
You see, the world stage isn't about friends and enemies in the traditional sense. It's about interests. After you understand that aspect, you will see that the very things you lay out in your post are exactly why the US is choosing this course of action. The military isn't stupid you know. They absolutely, 100% know power and how to achieve it. No question about that.
Take step back and realize that the entire world works this way. The more you understand 'spheres of influence' the more you will understand the *why* behind the what. Of course, its much much more complex than I have laid out but I was trying to keep my response limited to your post.
Actually there's a tad more to the battles around Guadalcanal. As you say, American air power controlled the area by day. However, the Japanese controlled it by night; the only way to change that was by breaking their control, and that meant surface actions. I'll agree, however, that if Halsey hadn't been so eager to take out the last enemy carriers the Battle of Samar wouldn't have happened. As far as the Navy's role in shore bombardment goes, I probably know more about it than you, because I was on the Gun Line in Tonkin Gulf back in '72, doing exactly that. Rail guns, with their impressive range will make it far easier for the Navy to project its power over the horizon without sending highly-expensive carriers in.
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Mount that railgun on a satellite and it can sink ANY ship.
And with the right electonic equipment, you could even target subs.
As of today,.. we have no counter to space based weapons.
I've always thought that most of the surface actions around Guadalcanal were defensive in nature, i.e: we were attempting to stop them from attacking our shipping and the land forces on the island. I've never heard them explained as attempting to "break" the control of the Japanese. In fact we got our asses handed to us in a lot of the surface engagements, and it was a combination of air power (preventing Japanese operations during the day) and Japanese mistakes (not attacking our transports after the First Battle of Savo Island) that eventually won the campaign for us.
I'll agree, however, that if Halsey hadn't been so eager to take out the last enemy carriers the Battle of Samar wouldn't have happenedHalsey took the bait hook, line and sinker. It makes you wonder what would have happened if he had been in command during Midway instead of Spruance. It could have wound up being a disaster for us. Would his aggressive nature have been inclined to retire to the east to avoid a night action as Spruance did? What would have happened if he didn't?
As far as the Navy's role in shore bombardment goes, I probably know more about it than you, because I was on the Gun Line in Tonkin Gulf back in '72, doing exactly that. Rail guns, with their impressive range will make it far easier for the Navy to project its power over the horizon without sending highly-expensive carriers in.Hey, I never disputed your knowledge. Was just trying to figure out the advantages/disadvantages of any rail gun system over existing technology. Shore bombardment is an interesting application for this technology and could fill the gaping hole we currently have in that area since the retirement of the Iowas.
Here's another thought: How do the power requirements of rail guns mesh with the power requirements of potential directed-energy weapons? If we build ships with power plants large enough to power rail guns, will they also be powerful enough to mount directed-energy type weapons, or I am getting ahead of myself here?
I want peace on earth and goodwill toward man.
We are the United States Government! We don't do that sort of thing.
As far as the shore bombardment, I never said you were disputing me; just letting you know about my personal experience because it was, for a change, slightly relevant. Don't know, though, about your last question.
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Well, you could be right. Although it isn't necessary for ships to outmass them by a significant margin for the latter to be properly classed as "bigger."
It would seem odd to design destroyers that are bigger than cruisers. That's a strange inversion of the normal order. What's the point? A destroyer's normal job is to protect cruisers and other capital ships. Maybe they're thinking of re-targeting this class of boat, making it a stand-alone offshore support ship, whatever.
If you are going to be tethered, you might as well scrap the second hull and put all the warfighting gear that would have been on it, on the power providing hull. If you do it right, the new larger hull will be faster even though you don't change the size of the power plant. ;-)
Good judgement comes from experience, and experience comes from bad judgement.
- W. Wriston, former Citibank CEO
>From 200 miles away, can you observe the fall of shot?
Easy, current Aegis radars can track ballistic missiles from 200+ miles away. Of course it has to be above the horizon. Actual impact will have to have another observer.
>2 minutes' worth of flight gives plenty of time for winds to drive the shot slightly off course.
Not true, most of the (200 mile) flight time will be spent in or near vacuum. In-atmosphere flight time will be very short on both ends, somewhere in the range of 10 seconds. As it traverses the atmosphere, there will not be consistent steady pressure in one direction or another. Instead there will be "noise", a series of small random deflections. With accurate remote weather sensors, even these will be known in advance.
Good judgement comes from experience, and experience comes from bad judgement.
- W. Wriston, former Citibank CEO
This system is *only* a megawatt class laser. The railgun system is in another league.
http://en.wikipedia.org/wiki/Boeing_YAL-1
Good judgement comes from experience, and experience comes from bad judgement.
- W. Wriston, former Citibank CEO
Jeez, so much wrong crap here. The projectile will, of course, be guided. As others have pointed out, line-of-sight warfare is passe, mostly because the battle is long over by the time combatants get that close. Leyte Gulf was the last time it was tried in any serious fashion, and then only because the Japanese were out of carrier aircraft. And they got slaughtered.
The problem with modern naval warships is, save for the super-expensive carriers, they don't do much besides protect the carrier. Sure, you have SLAM and Tomahawk to attack land targets, but those missiles are really expensive - you can't carry enough for an old-fashioned bombardment, and even if you could you'd go broke blowing up dirt fortifications with million-dollar missiles. Naval artillery is generally short range, so you'd better hope your opponents like the beach, because if they move inland about 30 miles or so you'll only be able to hit them with very expensive and finicky rocket assisted shells.
The railgun would sort of bring us back to the age of guns. The projectiles, which are GPS-guided depleted uranium or tungsten "darts", are supposed to cost less than 20k, are very compact (you'd be able to carry 40,000 or so), and will be able to reach land targets within 250 miles or so. They don't have explosives, but they come back into the atmosphere with such energy that they'll leave a nice big crater anyway. They'll have a mode for direct fire as well as ballistic when engaging other ships. In theory they could be used to attack air targets as well.
Last I checked there were some pretty large problems, though. For one thing, the enormous magnetic stresses will literally tear the gun apart after a few shots. Another problem is there's so much current going through the projectile you get plasma deposition on the rails, so there's a limit to the number of rounds you can fire before the rails need to be re-lined or serviced. And then there's the problem of getting all that power where it needs to be. The Navy originally wanted something that could fire every ten seconds or so, but busing all those electrons around was presenting more of a challenge than originally envisioned.
The complaint that was constantly voiced about retiring the last battleships in the Iowa class was that "littoral support" (pre-invasion bombardment) would suffer if we had to make a large invasion. This is probably what the rail guns are intended to make up for. Shore fortifications, and inland fortifications for that matter, don't tend to dodge incoming projectiles well.
Guided missiles are much better for attacking moving targets like ships. But even if the rail guns are used against ships, modern tracking technology and computer controlled aiming should make them at least as accurate as the old powder technology guns.
that could otherwise be spent on universal health care goes.
so if a guided tank round is pulling 6K G's the my guestimate was probably very low, the guided round might do mach 2 or a quarter of what the rail gun does.
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I saw this references on some documentary about the gulf war and Iraq war on PBS (I think). but I don't seem to be able to locate any on line reference to it so I might have it all wrong. Great, I didn't know this was done to change the ignition point. I did know that magnesium alloys are common in aircraft which is one of the things that make the metal burn to brilliantly in a crash. That's good to know. I was mostly tossing the ideas out because I didn't know. I'm grateful for your insight into this. I have seen things like magnetic induction cook top stoves melt aluminum before (after some non-warranty covered repair by a backyard mechanic) and I have seen to other strange things. I have also heard of RFI setting off explosives and suck but I wasn't thinking that normal "war" preparedness would probably protect against this stuff already.
Couple of things:
:-)
1. The automation of a catapult launch is a bit different from an autopilot. The pilot (AFAIK) still controls the plane once it leaves the deck. The computers just control the various factors of the plane's configuration necessary for a successful catapult. Once it's off the deck, it's still up to the pilot to keep it in the air and make the necessary clearing turns. Think of it more as a safety feature built into the fly-by-wire.
You can read one of the patents for such a system here:
http://www.freepatentsonline.com/6793176.html
2. On the subject of magnesium, I think you might find the NeXT Cube burning story interesting. Linky:
http://www.simson.net/hacks/cubefire.html
In particular, you'll note how amazingly difficult it was to get the blasted thing ignited.
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IHNIWITA (I Have No Idea What I'm Talking About) but ships do not move suddenly, and 200 miles is a long way inland to buildings and other land based targets, at mach 8 random gusts of wind will do little and I assume they will have a computer or 2 on their futuristic new ships to calculate a simple trajectory that take all of those things into account.
Speed is not the obstacle, acceleration is. ICBM simply are going on ballistic mode on reentry. Whatever speed they get is terminal velocity of reentry in atmosphere (at least If I remember correctly which is not a given). It is more or less a slow acceleration like a stone falling. Raingun OTOH give a brutal acceleration and if you see other comments above, you will see it more or less utterly destroy any guidance system leaving only a guide-less kinetic projective (they are trying to solve this problem but it is not easy). Which is why I am asking honestly , without guidance system, as a simple projectile, how precise are those over 200 miles. Even something as low as 0.01 deviation would be more than 55 yards deviation. So imagine what deviation it would be in normal circumstance...
By the way those projectile destroy with more than kinetic energy AFAIR, since they completely destroy themselves on impact, the splinter have a blast radius themselves where they destroy stuff.
C. Sagan : A demon haunted world:
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SAAB has just test launched three specimens of their new Mach 5 missile, the first hypersonic with remote control! http://www.domain-b.com/defence/def_prod/20071228_saab.html from 28 December 2007 "In an advanced test, Swedish conglomerate Saab, launched three hypersonic missiles to demonstrate controlled flight at extreme speeds. The missile, of which three were built, was test fired at maximum velocity, exceeding Mach 5.5, corresponding to 6500 km/h."
thats why a barrage of shells is fired, blanketing the target and a reasonable area around it to compensate for mis calculations.
remember, this isn't meant to replace guided missiles (although it probably could with the guided shell that you describe...), it's meant to supplement them.
A zeppelin-shaped cross-section, you mean :). If you want subsonic flight for your ring, yes, you need a traditional wing cross-section for your torus (just like the nacelle on a jet aircraft's engine). It won't produce lift, but should stabilize it quite nicely, even reducing drag a bit (as compared to a rectangular cross-section).
Something bad is coming when people are suddenly anxious to tell the truth.
Well, ideally, a projectile would be shaped like a zep, right? A toroid with a teardrop cross-section would be better than just shooting bearing housings, but a *good* system for launching things would launch minimized-drag objects and no toroid really can compete on that basis. But this system can only shoot toroids. What I'd like to build is a coilgun where the primary and core are wrapped around the projectile, so it doesn't need a hole through it, but I haven't gotten those to work very well -- they seem to work much better using a single massive pulse of DC, like a railgun. Still working on that... The other problem is that with both systems you want your mass to be as close to your core as possible to maximize the energy transfer efficiency, by avoiding the air gap loss, and any good aerodynamic shape is going to have lots of air gap loss since it only reaches its max width at one point. Frustrating when the laws of physics dictate contradictory shapes.
Nostalgia's not what it used to be.