ooo
You tube video please!
The US Navy will astound the world tomorrow by test-firing a radical new weapon system at an unprecedented power level. The new piece of war-tech on trial is that old sci-fi favourite, an electromagnetic railgun. According to the Office of Naval Research, which is in charge of the project, the electric cannon will deliver over …
You forget that it's actually a 32 mega-joule device. The 10 mega-joule effort was from General Atomics. Oh and you didn't mention Bae as the supplier..
I wonder if UK forces will get equiped with similar electric guns, although ours will probably stop the electronics from working, and the vehicles housing them may explode in sparks.
Hopefully the boffins will sort out the issues and get this one into service. It would eliminate a lot of current headaches for military mariners, especially transport/storage of those pesky propellant cartridges.
And anything that 'tips the balance' back toward *real* fighting ships, away from aircraft, missiles and over-inflated floating runways, would be very welcome indeed. Now if we could do something similar underwater ......
"A willing foe and sea room"!
If the projectile is still travelling at Mach 5 when it hits the target, doesn't that mean the projectile has a virtually flat trajectory? If-so, it'll be of limited use in shore-bombardment where targets tend to be in-land, behind buildings, forests, hills, etc.
You could drop the rail-gun's muzzle-velocity, but you also reduce the impact's kinetic-energy - In this case isn't "old" HE ammunition better?
If this "gun" fires projectiles at such high velocities mach7? and the projectiles do not have explosive warheads, then I'd have thought that the damage they could do to other large surface vessels would be minimal. You need to punch an lot of holes in a ship to make it sink, as any U-boat commander knows (Deck gun action). Of course damage to smaller objects like aircraft would be critical. I also question the wisdom of having this as a primary weapons system, reliant upon the same source of energy for propulsion, all controlled by windows for warships.
OK it might just be possible to shoot one or two rounds, depending on the recharge rate, at an attacking aircraft with one of these thingys, but they won't be much good against submarines. As the old (submariners) saying goes:
"there are two types of naval vessel - submarines and targets"
Oh yes, what happens to all the loose metal on a ship when it fires it's rail gun, will there be more friendly casualties from flying spanners etc. than the enemy will suffer?
I wonder how long a barrel is needed to impart mega joules to a pellet via EM attraction alone...
You need a pellet tight enough so it is accurate but loose enough so it doesn't friction weld to the barrel.....
We talking smoothbore or rifle here?
Errrm they do know that the sea "moves a bit" don't they ? Precision ballistics at sea?
Oh just put it on the pile with the others Lewis.......
I'll mention it next time I'm at the gun club and we'll all have a good chuckle..
Surely most of that article is idle speculation.
Rail gun slugs that steer themselves in flight? Not even in most sci fi, the whole point of the slug is that it's just a lump of metal.
Even at mach 7 this will be of no use for shooting down planes, unless they are only 50 feet from the barrel. The ballistics computation might be fairly straight forward, but you'd only ever hit a plane that was flying on a steady trajectory.
Mach 7 is 2.3 Km/s, so for a target that's 15 km distance it will take the slug 6.3 unguided seconds to get there, any course or speed change in that time will cause a miss, and planes can engage ships from much further away than that.
Rail guns may well replace most of the projectile weapons on a warship, but that won't really alter the fact that air power decides the winner.
Ah, but this is just the begining. Once we crack it as a weapon all we need to do is make a bigger one and then we can fire stuff into space. Like new parts for the ISS. Or perhaps we can use it to get rid of all that pesky uranium we have left over.
Failing that we could build a REALLY big one and get rid of the moon so that no-one can build a "tractor beam" and pull it into the ice caps flooding the earth....
one coat with extra long sleeves tied behind the back please.
So, 200 miles after being fire, the munition has only scrubbed ~600mph (no idea what angle this thing is going at, so altitudes will change speed greatly) from it's 2380mph start point....??
That seems like a very slippery round to me... maybe someone knows some numbers on normal bullets, that'd be interesting...
More accurate strikes... hmmmmm. Well it'd be an improvement if the yanks correctly identified the continent, let alone a particular vehicle :-)
I'm not sure about surgical strikes though. Even a those speeds my car would have moved before they got the "shot" arrived and I may have stopped at lights if they try and predict my movement. Might also prove problematic if I'm not in line of sight. Or are you saying they can be guided? In which case they may be prone to jamming and heat problems.
On the subject of surgical strikes, wouldn't something hitting a car at Mach 5 be likely to pass through and hit other objects or spread pieces of car at high velocity? Obviously if the car was a Toyota pick-up you'd be OK but for normal cars it could be a problem.
On a more serious note. Isn't one of the problems of modern warfare that the country being attacked feels they can't compete with "cowards" attacking them from afar, so they resort to suicide bombing and so on? Just a thought......
At the risk of sounding too much like a train-spotter, it's worth mentioning that 1 megajoule is 1 megawatt for 1 second.
Once this is clear, the whole article is much easier to understand - For example, the 100 megawatts to provide 64 megajoule is actually a burst of energy lasting roughly half a second.
Coat, door, now...
Also, @ Pete
"Oh yes, what happens to all the loose metal on a ship when it fires it's rail gun, will there be more friendly casualties from flying spanners etc. than the enemy will suffer?" Most of the stuff on ships is not made of ferous materials. It tends to rust dontcya know. (I know some things are, but not spanners etc).
re a British rail gun.
a couple of yrs ago, I did some work on a computer system related to a Dera/Q-TipEx/dstl project.
computer's user/owner had just returned from a field trip to a test site somewhere in the UK, and described the test firing of something which sounded remarkably like a rail-gun (the person in question was doing other research, but got invited to see this demo - said, there was a lot of Brass and suits there, both UK and foreign )
suppose you can treat it as a FOAF story, of sorts.
Besides, a British Rail gun? (cue obligatory jokes about speed of projectiles, arriving late on target, failure to fire due to leaves on line etc etc..)
Black Helicopter because.. I'm sure the Whirlypig that was hovering outside my window t'other night was black.
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"You need a pellet tight enough so it is accurate but loose enough so it doesn't friction weld to the barrel.....
We talking smoothbore or rifle here?"
Oh, c'mon - surely there is no barrel - it's called a railgun for a reason.
"Errrm they do know that the sea "moves a bit" don't they ? Precision ballistics at sea?"
Since the time of the HMS Dreadnought ship batteries fired sunchronised with the ship roll. And nowadays the girostabilised platforms are not unheard of either.
And about the shore bombardment: the Mach5 projectile will deliver the necessary shock and awe with its sonic boom. Joke.
Yeah, but to get the slug to move from a dead stop to mach7 (2.3 Km/s as is pointed out above) in half a second you'd need a barrel 575m long.... (if I can remember my old mechanics lessons....)
I should imagine you'd need to get that down to more like 10 or 15 m as a maximum, and that's going to be a very very short pulse.... Not so easy
Why Paris? Why not :-D
With regard to the gun supposedly bobbing up and down while at sea I can't see that being too much of a problem.
Firstly big ships are reasonably stable in all but the roughest weather, although I agree there will still be some movement.
Secondly, if BAE are making it they could just mount it on a gyroscopically stablised platform, much like the one used for the main gun on the Challenger 2 tank.
If they resolve the issues of the barrel's longevity and the rate of fire I suspect it will be quite an effective weapon. Certainly I would not like to think of a hail of Mach 5 rounds heading towards me!
Just imagine trying to convince the common man in 1944 that there was a bomb that could vapourise vast chunks of a city.
Imagine if you will trying to convince a man with his musket that one day his bullets would be self contained with their own proppellant.
Imagine trying to convince a Halberdeer that he was soon to be made redundent by a man with a musket.
Imagine trying to tell a guy in the 1950's that we'd have super computers, mono trains and hydrogen bombs.
I think in all instances they'd think you were start raving mad.
@Steve, I didn't see anything about projectiles steering themselves, the reference to steering is more about the projectilles flying in a predictable course.
I don't think it's meant for the Navy to be honest, although I like the idea of using a jack-up barge style ship to mount it on, giving it a stable platform but I imagine those things take quite a while to get in a suitable position and to actually lower the legs, and currently, models only have a leg reach of 48mtrs down meaning they'd probably have to be relatively close to the shore, rendering any sea-based advantage useless as it would be something of a sitting duck whilst it's like that.
Instead, I think it could be being developed for space (low-orbit?) use in major risk situations where you'd only need a handful of shots to do the job (maybe shooting down enemy ICBMs etc, I'm sure you guys can think up other space bound applications), it has a minimum range of 200mls, space would offer a pretty damn steady and safe operational platform, and it could be positioned above anywhere in the world in relatively little time, plus it would solve the problem of trees getting in the way etc.
So, what do we think?
@Billy
Yeah, but "A bloody war and a sickly season" was always my least favourite.
Also:
Stabilization of weapons on naval vessels is quite advanced - they're pretty accurate, actually, as are the control systems used to guide them. Don't you folk remember all those WWII movies where naval guns where hand cranked yet still reasonably accurate in the hands of trained gunners? Technology has come a long way since then.
Although the article doesn't expand on the point, I think the idea behind the rail gun, at least for long range shots, involves a GPS-guided projectile with steering fins. The material that gets zapped by 100MW would just be the propellant, with some sort of "wadding" between the propellant and projectile. this could actually be more gentle than the "big bang" used in conventional propellants. For short range AA fire, there'd be no need for a separate projectile if a slightly different type of fusable 'shot' were used. Of course, I may not know what I'm talking about, so I'll grab my coat just in case.
With all the work that's needed to make the things last a few shots, let alone the power needed to drive it, won't we have practical naval laser cannon first? And forget the spanners, what happens to all that sensitive electronic kit onboard when you start pumping out sharp EM spikes with each shot?
200km or 500m, there is still the same old problem of finding the target and then aiming at it before it can clobber you, so with the current generation of radar and fire-control systems I'd say aircraft still have a fair chance with long-range sea-skimming missiles. Longterm, the only real defence against over-the-horizon sea-skimming missiles is to be able to spot and track them earlier, and that would probably need some form of automated sattelite system that can look down and detect incoming aircraft or missiles by IR, and either aim the ship's weapons remotely or feed the data into the ship's fire control system to allow very quick engagement. In theory, such a system could even detect railgun rounds at mach7 (bet they get hot!) and provide sufficient warning for the target ship to launch counter-fire.
Gotta go with the skull 'n' crossies..... ;)
"They could take out a single vehicle from far out at sea, perhaps, rather than pulverising a whole area like present-day cruise missiles"
yeah, in much the same way that a plane currently could take out a single [enemy] vehicle from pretty close up, but generally tends to hit a hospital a few miles away instead.
As for 'pulverising a whole area' - yes, if you take 'area' to mean '3 countries or so' [ref: the American cruise missiles that hit Syria when supposed to be targetting Iraq...]
There isn't a load of recoil on a railgun if you're on a reasonably stable platform, like a tank or a ship, but that's because the energy is supplied continuously during the acceleration at a steady rate. In space, it's the same amount of delta-V, which is still more than enough to knock your satellite out of orbit.
Not a good idea.
from what i remember, the power requirements for these are so high, that every shot you fire vapourises part of the rails from electrical arcing. One shot from a railgun isn't that impressive, any university physics student could cobble one together in their spare time.
The problem is firing several shots in a row without having to rebuild the gun, which is quite a handy feature for a weapon of war.
don't worry about ship motion
don't put the ship on stilts
don't steer the flippin' slug
map the wind speeds and directions between 'here' and 'there' up to 20 or 30 kilofeet
do lots of sums v quickly in a machine called a compooper (or summink like that)
shoot the slug on a high paraboloid trajectory with the initial aiming angles compooped to account for all the variables
PH avatar - 'cos she could have told you this!
[There isn't a load of recoil on a railgun if you're on a reasonably stable platform]
There isn't any recoil regardless of platform. Recoil is a result of the gases expanding pushing the projectile forward but also pushing the rather heavier gun backwards.
In a rail gun the "recoil" force is applied perpendicular to the direction of travel of the projectile, which explains why rail guns tend to bend/explode horizontally a lot :o)
Until they find some materials that are very conductive, extremely heat resistant and non-magnetic proper rail guns aren't going to appear anytime soon. If they want to use high velocity non-HE rounds for precision strikes they'd be better off filling a satellite full of large ceramic "bullets" and dropping them from space ICBM style. The kinetic energy they would deliver would dwarf a few kilograms of copper shifting at mach 5. It also has the advantage that it's all old school tech - no need to invent anything.
We need this, we should build this, duno why exactly but we should. Erm perhaps we could then civilianise the tech for some sort of space launchy thing for non squishy cargo or make mass drivers for passing stuff around the solar system like some cosmic game of catch. Good way of getting stuff to the moon and back when you have set up the infrastructure. Just dont stand in front of the earth when your catching, be a bummer if you missed.
We should also make em smaller as well, fit them to tanks, the tankies would love the idea of driving around sat next to a few tonnes of propelant and warheads. Man portable ones would also be cool but then we would get the phrase "I'm Out!" replied by "Of What Ammo or Batteries?" Infantry bunnies may or may not be happy depending on the weight saving.
I demand Future Weapons and other Military Pr0n show me you tube video!
For those ballistics experts who think railguns don't have moving, touching parts.. http://en.wikipedia.org/wiki/Railgun - Apologies for using wiki.
A railgun pellet IS the barrel albeit twin bore. It slides on one or two rails. So we have a pellet looking like a mini rocket ship with two holes in the bottom. They damage the rails as they leave.
So basically a railgun is a bow "firing" high-speed arrows. It will recoil as Newton's third still applies. A small mass given a large acceleration will recoil like a large mass given a small acceleration.
No, another one for Scotty's "cool but impractical" file.