No military reason? Are you mad, man? Loitering drones!
Also, heavy lift.
This link expanded my language today – first time I’ve ever seen “stare” used as a noun, used to indicate the capability of looking at a single object over an extended period. “…an airship can provide continuous communications on the battlefield and stare you don’t have today,”
I apologize for getting defensive about it.
It sort of does. At least “invisible” as a practical matter in terms of detecting and targeting. I don’t know that a railgun would so accurate as to hit a supersonic target 20+ miles away.
Then again, they are testing laser-based antiaircraft weapons.
[QUOTE=ExTank]
That’s not an argument I’m advancing, although rail guns are not as far-fetched as some here want to portray them. The basic technology exists and has been proven, it’s now a matter of refinement into more practical forms.
[/quote]
Seems like they aren’t that far off
http://www.military.com/features/0,15240,160195,00.html
But if anything, they are an argument against bringing back the battleship. Why have a big, slow battleship when you can put a gun on a fast destroyer that can deliver enough power to take out any battleship from 200 miles away?
It doesn’t matter what systems you have if you can’t see your target to hit it.
I don’t see why not given the accuracy of the prototypes.
Both systems require a lot of power to operate. What give the best bang for the buck. I can see the laser being more accurate, but deliver less punch as a weapon.
IMHO, it is a trade off. The idea of a battleship is to trade blows: To give it and to take it. If the larger heavily armored ship can take hits while still giving it back to the enemy, then it makes some sense to have such a ship. Otherwise, I agree, put your weapons system on the cheapest and fastest thing out there.
Well, fighters do have this little advantage in being able to make frequent minor course corrections that would defeat straight line flight projectiles. You don’t even have to know where they are incoming. Once you’re in range of the ship, it’s time for a jitterbug flight pattern.
Right, but how thick does the armor have to be to stop projectile traveling at Mach 8?
A projectile flying at 20km/s is very hard to ‘jitterbug’ out of the way of. If you had something like the Phalanx system only with ammunition that is multiple times higher velocity and without the casings that traditional ammunition require, you can put up huge volumes of fast flying objects that increase the likelyhood that the target will be hit. One hit with such a weapon equals game over.
[QUOTE=msmith537]
Right, but how thick does the armor have to be to stop projectile traveling at Mach 8?
[/QUOTE]
I do not know. Is it more than the protection required for a hit by a 16" shell?
I thought I’d do a little math to compare the kinetic energy of a battleship shell with a rail gun shell. I hope someone will check my math and straighten it out if I’m wrong.
We don’t know the mass of a rail gun “bullet”, However, energy increases faster with increased speed than it does with mass. Double the mass of a bullet and you double its energy; double the speed of the bullet and you quadruple the energy.
Wiki says an Iowa’s gun fires a 1,000 kilgram shell (I’m just picking a convenient number within a range of shell weights that it might fire) with a muzzle velocity of about 820 mps. Kinetic energy = 1/2 x mass x velocity squared, which for this shell, works out to 336,200,000 joules. That’s about 336,000 joules per kilo at that speed
Another Wiki page supposes a rail gun velocity of Mach 10, about 3500 mps.
For the two projectiles to have the same amount of kinetic energy, the mass of the rail gun projectile would need to be about 55 kilograms. The battleship’s warhead would of course add an unknown amount of more energy to its destructive power.
A rail gun projectile fired at Mach 10 has 6 million joules per kilo of kinetic energy.
I have no idea if it is or will be practical for a rail gun to fire a 55 kg projectile. But I’m pretty sure it could fire 55 1 kg projectiles, and any seaworthy scow can probably carry fifty five times more1 kg projectiles than a battleship can carry 16" shells.
Call us back when there is such a thing as a phalanx/minigun/gatling rail gun.
There isn’t even a production rail gun at the moment. If they ever do put one on a ship, the next logical progression is to make it cycle faster. If the discussion is whether a battleship is needed, that is when it starts to happen. When it does, the pendulum with swing and it will be the aircraft carrier that becomes obsolete.
There is a big gap between “we’re testing rail guns for navy ships to replace cannons” and “fighters are obsolete because rapid firing rail guns on ships can throw up walls of hypersonic slugs”.
I’m pretty sure fighters will be obsolete once rail guns are installed. People can’t withstand the g’s to dodge a rail gun round. Missiles will effective for a longer period of time until phalanx type rail guns are built.
First of all, current rail guns take a significant amount of time to recharge the electrical systems for the rails. A rail gun that could fire once per five seconds would represent a huge leap forward. Modern rail guns also have ablative components in their “barrels” that wear down and need to be replaced occasionally. We’re a long way from anything representing rapid-fire rail guns of any projectile size.
Second, I’m worried about the idea of throwing up thousands of hyper-sonic slugs because of the effects such missiles would have when they came down. If they’re traveling only 3.5 kilometers per second, as you suppose, they’ll come crashing down to earth in a truly destructive way. Maybe you could get away with that in a blue-water Navy battle, but near shore that’s a big liability to civilians. However, if your missiles are traveling 20 kms (as suggested upthread), then we’ve got a different, somewhat longer term problem: your missiles have escape velocity from Earth! Now, they certainly won’t fall back to Earth, but since they don’t have solar escape velocity, they’ll remain in orbit around the sun with orbits perpetually crossing Earth’s orbit. That’s no big deal for a single rail gun slug, but with the millions or tens of millions of slugs that would be fired by large-scale deployment of rapid-fire anti-air rail guns in a large war, you might start to worry in the long run about the impact (pun intended).
“Ok boys, we’re in range of the rail guns. Minor course or altitude changes every few seconds until we’re on target”
Doesn’t seem all that hard to me…
I think you’re overestimating the flexibility of fixed projectiles.
You’re underestimating how hard it is to hit a moving target making unpredictable course changes. Rail guns will never be able to reliably hit jets at even sort-of long distances. To shoot down a jet will require something that can change course in response to a jet’s course changes, or something that travels basically instantly to the target (like a laser).
I think crewed bombers and fighters are approaching obsolescence already, rail guns or not. Drones and missiles are where the military is going.
I don’t think you understand how fast 20km/s truly is, or how long a person can sit in a plane required to dodge shots that move so fast, or the stress on the plane, and the amount of fuel required to keep it up and get to the destination.
And if they’re saying 20km/s for smaller projectiles before they even have it in production, isn’t it kind of like predicting how fast planes will actually fly based upon the Wright Brothers first flights at KittyHawk?
Maybe not in the short term, but the days of war planes (at least with people in them) are numbered.
Theres also the teensy problems of earth curvature and the like - 200km is a long way, so lower level flying is one obvious option.
And from what I can see they’re talking double or triple the speed of conventional means, not 20km/s. Missiles are going to still be the obvious choice for long range moving targets until/unless they can add some kind of homing component.
Otara
It doesn’t matter how fast it is. Modern aircraft can launch anti-ship missiles from at least 20 km. That means it takes a rail gun round 1 second to reach the the target before it’s within a comfortable firing distance. Modern military fighter aircraft travel somewhere between .5 and 1.0 km/s at top speed. That means your target has traveled a kilometer in the time between when the round fired, and when it reaches its target. You’d literally miss by a kilometer, unless you lead your target by a kilometer. The tiniest, most insignificant trajectory change your target makes would make it literally impossible for you to predict exactly where it will be with enough accuracy to nail it with a rail gun round. We’re talking course changes so minor the pilot wouldn’t even feel it. All they need to do is make your predicted shot be 5 feet wrong in order to miss them completely, and they have a full second to do it.
Meanwhile, the machine that costs 1/1,000 of what your giant battleship cost just sank your gajillion dollar investment, killing 1600 people on board, using 1970s technology.
No, it’s not anything like that.