I Sing the Body Electric
I thought for a mo' you were referring to Ray Bradbury. As you were.
Globe-straddling weapons megacorp BAE Systems is pleased to announce that it has inked a deal with the US Navy to build a new electromagnetic hypercannon. "This EM Railgun contract is a continuation of BAE Systems’ dedication to delivering advanced technology for tomorrow's Sailors,” said Jim Schoppenhorst, BAE veep in charge …
Accuracy of course. A lump of iron travelling at mach 5 won't get blown off course by a hurricane, let alone the sort of weedy light breezes and changes in air density that affect traditional naval shells.
The difficulty isn't making the thing fire, it's finding materials for the rails that won't melt or wear out after a couple of shots.
Totally cool and small ones are easily built at home.
".....coastal areas of the world."
Dunno about that. One thing that would definately be capable of mounting and powering a humungous, ship-fragging railgun would be a coastal defence emplacement.
Just out of interest and 'cos I like my heavy artillery to be mobile, exactly what do you call a railgun mounted on a railway carriage? A railrailgun? If you mount two, is the result a railrailgungun?
Or even better, suspend a field of iron filings in front of the target, maybe attached to that sticky fly paper. The magnetised projectile will fly through them, then stop and try to brush them off with no success. It'll hang there spinning in the air trying to reach the bit between it's shoulder blades.....
Perhaps this is the initiative that the UK needs to build it's high speed rail network from coast to coast, 25Kv overhead, plenty of amps, quick deployment. All for the cost of a couple of Aircraft Carriers.
Perhaps we should pass this one over to Cpt. Deltic for a spreadsheet or two.
(This idea is at least as sane as the IEP)
... have been delayed for 20 years because of either leaves on the line, or the wrong type of snow.
The latest version now works, but is never less than 10 minutes late, and often up to an hour late in firing.
Also, despite claiming to be amongst the fastest in the world, it is also painfully slow; 3 legged donkeys have been known to be quicker.
Coat complete with notepad and pencil for train numbers
The "flames and other symptoms" is really just air, bits of the projectile and chunks of the barrel turned into plasma and expanding through the barrel. The electromagnetic hell which occurs in the "barrel" at the time of shooting causes this. Ever saw an arc welder in action? Related principle, same effect, yet no gunpowder either. Try to imagine a 64GigaJoule arc welder, trying to weld two rails few cm apart, separated by an iron slug and held firmly in place by the gun harness, back together. In a few nanoseconds.
'But I still don't get why there are flames and other symptoms associated with chemical explosions. Why?'
One of two possible explanations come to mind:
1: The whatever-the-hell-its-made-of is being heated by friction with the air to a point where it is reacting with oxygen - i.e. burning; or;
2: Industrial Light and Magic were called in to make it a lot more impressive to an audience used to Michael Bay features.
Never mind solid metal shot, why not a metal "shell" and back fill the thing with concrete? Cheap, stable and the heat generated by the metal outer hitting a target at a reasonable speed is liable to cause any air pockets in the concrete to make some really great schrapnel...
..OK, maybe not.
Of course one other thing to consider would be; what happens if they make a DU round for this thing?
How long before the 'simple' iron slugs becomes heavily computerised course correcting beasties than can attempt to fly through the front door? You just know the US navy won't be able to resist the attempt. Yes I know any deviations would only be slight given the initial vector and lack of thrust on the slug but...
Well you know how these projects spiral out of control.
a Phalanx 20mm radar guided anti-missile cannon would not be able to stop this... the phalanx was designed to put proximity fused cannon shells into the path that a missile passes through... and a missile is relatively soft skinned because certain parts of it such as radomes/camera windows have to be able to see the target to home in on it... a solid lump of steel flying along at Mach 5 would be immune to shrapnel...
I'm surprised the USAF hasn't proposed putting loads of iron bars into orbit with simple guidance packages and small motors to de-orbit them and home in on the target as required... as anti-ship weapons, they would be perfect as they would be coming in from well above any armour a battleship or aircraft carrier could have... would have to be pretty meaty armour to defend against a 20kg iron bar coming in from above at 7 kilometers per second... approx 980 megajoules...
"How long before the 'simple' iron slugs becomes heavily computerised course correcting beasties than can attempt to fly through the front door? You just know the US navy won't be able to resist the attempt. Yes I know any deviations would only be slight given the initial vector and lack of thrust on the slug but..."
The MOST important part of any defense project is the upgrade. Every major weapons system manufacturer depends on these to make the real money.
When fleet meets coastal artillery, fleet loses. That has been the case since the invention of the battleship and probably even before that. In the Japanese war, WW1 and WW2 all coastal artillery defences had to be countered by infantry advance on-shore and fleet by itself never managed to succeed. The Japanese fleet did not score a single successful hit vs Russian coastal artillery while taking regular damage from return fire at Port Arthur until their army managed to neutralise the coastal guns in artillery duels from the back where they did not have firing vectors. Same for the Dardanelle straights and Ezel in WW1, Kerch in WW2 (which the Russians had built with 360 degree fire arc so it actually stood until it ran out of munitions) and so on.
As far as US navy dominance... Well... Nobody has fired a Granite or Sunburn missile at it just yet. That is when we will know if it is really dominant. I somehow doubt that.
Actually, they really are intending to do that. You must be psychic!
They're only firing inert rounds for now, while they're trying to get the basic gun to work. But other people are working on how the hell to make a GPS guidance system that will survive kilo-G accelerations. They really do want "Which window do you want it to go through?" levels of accuracy, even after a 200km flight.
The Army managed to get this idea to work with the Copperhead anti-tank artillery round. But I'm guessing the acceleration of a rail-gun round is a couple of orders of magnitude greater still
...I am almost ashamed to admit that the moment I hear the words "I Sing The Body Electric" I start singing the song from "Fame".
For those too young to know the reference... Screw you! Bloody Kids! Nothing you have ever created will reach the peaks we reached! Everything you ever do will be no more than a pale shade of that which we have done! We were more relevant and our experiences more meaningful!
For those too old to know the reference... Screw you! We are the new generation! Screw you with your sepia tones and musty stench of old velvet! You are dried up pressed flowers and mounted butterflies! You are the dessicated carcass of what was once life! You are a museum piece sealed in amber! Unliving but won't die! Stay out of our way for we are the future!
I sing the body electric, I celebrate the me yet to come, I toast to my own reunion
WHEN I BECOME ONE WITH THE SUN!
you all suck.
But I will be far more impressed when they tell us just how they plan to keep the railgun from chewing up its rails in the first few rounds, considering that you have a mach 5+ projectile in contact with those rails, not to mention what the plasma and all that electrical energy will do. I would imagine it would make barrel erosion problems in standard cannon seem mild by comparison.
Whenever you get huge amounts of energy being dumped quickly, stuff breaks. That's why conventional naval guns can only fire a limited number of shots before being refurbished. Rail guns are a lot worse and none survive more than a couple of shots. The ammo might be cheap but the guns are expensive - no bit win if you can only fire two shots and then have to go home.
The ammo can't actually be that cheap. It is all very well firing a slug 100m into a pit. But firing accurately over 200 miles is a completely different matter. The shells will need guidance to get them on target. That guidance will need electronics, fiddly bits etc. That electronics will have to survive the immense magnetic fluxes, energy and acceleration of launch.
The engineering is far from done.
Barking mad Jerry Pournelle made a serious proposal along these lines back in the 50's when he was working for Boeing (rather than writing right-wing "God Bless Yankee Knowhow" hector excuses for sf novels). Was called Project Thor and was basically supersized crowbars with guidance fins, a simple guidance computer and a small rocket motor for de-orbiting. The supersized crowbars were supposed to be about 20m long, and coming in at orbital velocities (~10km/s) would have the same effect as a small nuke, with none of the longer lasting side effects (apart from p**sed off natives whose loved ones were in the way).
Screw railguns, they have a tendency to burn up after a few shots.
Instead, use gauss guns which magnetically levitate (and then propel) their shot, allowing them to fire any size of shot (Or even multiple shots in one go) and not having any problems whatsoever with barrel wear. Additionally a properly constructed gauss gun won't put immense stresses on the firing assembly because the guide rods try to propel eachother away.
The problem, ofcourse, is that you have to fire a ferro magnetic projectile, while railguns can throw anything sufficiently conductive.
As for guidance, even if the acceleration (Which can indeed go into thousands of Gs pretty easily) could be overcome, do you have any idea as to the magnetic field strengths inside a munition being fired out a rail/gaussgun? These things will make MRIs look like bar magnets in comparison.
Proper shielding on the outside of the cannon should be able to limit the magnetic field outside the gun to safe levels though, after all we're producing a very small, very intense magnetic field.
As for the person who suggested using a magnetic field of opposite polarisation... Railgun shots need not even be ferromagnetic, no magnetic field is going to do much. Even if they were iron, steel or other magnetic materials, your magnetic field will do nothing at best, further accelerate the projectile at worst (And no, you can't pull the projectile off-target, you don't have enough energy for that)
A couple of questions:
Against which enemy or enemies does the USA need a 200 mile shelling range? Can't be Russia or China, 'cos they've got the submarines to sink these ships in half an hour. Most of Iran is out of range, unless the septics can build one in the Caspian Sea, so I reckon that leaves North Korea and the UK, 'cos our subs are all laid up in Rosyth dockyard.
Secondly, I'm curious about barrel length. I fancy this will severely limit the possible angle of elevation, unless the ship is to be modeled along the lines of the Pepsi Max at Blackpool.
Isn't there one of those geek "rules" that says something like "Reality will always be wierder than the most outrageous joke or satire"? We have here some more evidence supporting that statement. :-)
@robbie: I guess 200m is the best they can aspire to at present, rather than the most they think they'll ever need. Come any further advances in tech, and they'll gleefully extend the range to hit targets ever further inland. Anyway, we already have a large proportion of the human population within 200m of the sea. Russia, China and Iran may be out of range, but there are lots of smaller countries they can terrorise with such a weapon. And the Marines will love it - Having heavy arty support you as you land has got to have advantages over just having Harriers.
@Greg Trocchia: What I read years ago suggested that "Mach 5+" at launch is in fact Mach 7. If that is still correct, the shell only loses 2/7 of its velocity before hitting the target - A smaller fraction than I would have thought, but I guess travelling 200m at hypersonic speeds happens too quickly to matter much to the shell.