OK, say we accept that figure, why wouldn't the overall recoil of a rail gun with a similar muzzle energy be the same? According to newton's third law (wasn't it?) for every force there is an equal and opposite force (or something close to that), so if you send a projectile with a muzzle energy of 33MJ, using a railgun, a conventional gun and even a slingshot, the recoil energy would be the same wouldn't it (assuming no muzzle brakes etc)? The differences would be in the peak loadings or lack thereof.
Navy Sets World Record With Incredible, Sci-Fi Weapon
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OK, say we accept that figure, why wouldn't the overall recoil of a rail gun with a similar muzzle energy be the same? According to newton's third law (wasn't it?) for every force there is an equal and opposite force (or something close to that), so if you send a projectile with a muzzle energy of 33MJ, using a railgun, a conventional gun and even a slingshot, the recoil energy would be the same wouldn't it (assuming no muzzle brakes etc)? The differences would be in the peak loadings or lack thereof.
Because a rail gun does not use a chemical propellant so there is no contribution to the recoil energy from the propellant mass being ejected from the gun barrel.
The slingshot is a little tricky, because you do get some recoil from the elastics when they snap forward, then a reverse recoil when they snap back a fraction of a second later. So the total recoil is technically only the projectile.
The peak loading is primarily a function of the recoil energy and the recoil distance. Double the recoil distance and you half the peak recoil (assuming that you are not using FOOB [Fire Out Of Battery] technology, etc.)
Why does it need to be turret mounted? Before the AGS was selected for DDG-1000 one of the main competitors was a vertical launched gun system that did away with the turret all together.
The VGS [Vertical Gun System] can only function with smart rounds, because the guns cannot be aimed, you point the ship bow on to the target and shell does the rest. Because the elevation cannot be adjusted it has a minimum range of around 40km, and is therefore worthless for surface warfare or AAA.
As a dedicated fire support weapon it would have been superb. The arrangement (2 side-by-side barrels mounted with the breaches just above the keel) and long recoil combined a fire-out-of-battery design allows it to be mounted in smaller hulls than a turreted weapon. The automatic loader, while mechanically extremely simple (and therefore reliable), can maintain a high rate of fire from a ready magazine that could exceed 200 rounds before need for human intervention to transfer additional shells from the auxiliary magazines.
Most likely reason for abandoning the concept was because it could have eliminated the justification for the large hull DDX program.
OK, thanks for that clarification - makes sense. Secondary recoil (of the burning propellant) is the additional component.
For those wishing to read more (I did) - this helped: The Physics of Everyday Stuff - Gun Recoil
Sampanviking
Banned Member
It sounds an incredible system and one which I am sure will not come cheap, either to build, use or maintain.
What would the USN be prepared to lose in order to have it?
What would the USN be prepared to lose in order to have it?
localhost127
Member
how would a ship have to be constructed (aluminum?) to be passive to the magnetic fields imposed by the railguns?
How small can you make the projectiles and still withstand the forces they would encounter at launch and during flight. The question is important if these kinds of gun can be effectively used in the AA role. The second question for such a gun would be what would be the firing rate for the smallest caliber round that is practical.
I do not know where you got "'Blitzer' railgun already 'tactically relevant', boasts maker" from that article. The closest I could find was “General Atomics conducted the test in association with the Office of Naval Research, and plans on continuing testing through next year, when they will finally start launching "tactically relevant aerodynamic rounds".
Presumably this means that they will be moving from firing simple aluminum slugs to a design with an aluminum discarding sabot, probably an APDS round. I do not think that they have a design for HE yet, there are a big problems having high explosives around mega-joule electric arcs.
Thats is the link.Not my words
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IronsightSniper
Member
Rail guns are nice if you want to impress your local fan boys and deal with asymmetrical threats. But nothing as of today competes with the effectiveness of a long range precision guided missile.
Missile can be shot down. a tiny metal slug travelling at 7 times the speed of sound are a lot more difficult to intercept. also, missile are expensive. How can you justify using a million dolar missile to destroy a target that may worth 1/10 of the missile, or even far less. a metal slug on the other hand, are cheap. all the cost and complexities are on the launcher. hell, the round doesn't even need an explosive.
IronsightSniper
Member
They talked about Expense, but we're the U.S., we can afford it!
There are also, LO and VLO cruise missiles in service/development. Some examples I can come up at the top of my head is the JASSM and the Kh-101.
Then there's the question of range. Is it justify to bombard a target from 400 km away when that just happens to be the range for many Anti-ship missle systems?
Finally, a large metal slug actually has a relatively large RCS.
There are also, LO and VLO cruise missiles in service/development. Some examples I can come up at the top of my head is the JASSM and the Kh-101.
Then there's the question of range. Is it justify to bombard a target from 400 km away when that just happens to be the range for many Anti-ship missle systems?
Finally, a large metal slug actually has a relatively large RCS.
what purpose is this rail gun going to serve exactly?
ok guys bare with me here...i tried to read a lot about this rail gun....i'm simply trying to figure out its main purpose....i understand the bullets fly real freakin fast to hit its target so its going to be better than a subsonic missile but then....its only a bullet ain't it....what is it going to shoot down little sea birds at the speed of mach 7 or some funny chinese frigate or fast moving coastal patrol boat.
Any other likely targets i feel could be some dumb iranian torpedo....please share your thoughts on this
ok guys bare with me here...i tried to read a lot about this rail gun....i'm simply trying to figure out its main purpose....i understand the bullets fly real freakin fast to hit its target so its going to be better than a subsonic missile but then....its only a bullet ain't it....what is it going to shoot down little sea birds at the speed of mach 7 or some funny chinese frigate or fast moving coastal patrol boat.
Any other likely targets i feel could be some dumb iranian torpedo....please share your thoughts on this
The proposals seem to center around coastal bombardment using GPS guided projectiles. The idea is that the rail gun will out range the opposing guns so the ship will be safe (Yes, we all know that the rail gun will be out ranged by anti-ship missiles, don’t belabor the point.) while having a faster response than missiles and not requiring aircraft or drones to penetrate air defenses.
I get to a forbidden site using this link.
Interesting, I cannot either, but if you open the Atomic Rockets web site in your browser first it works fine.
Try Atomic Rockets: Space War: Weapons – Conventional#Kinetic_Kill_Weapons~Railguns
Armoredpriapism
New Member
What are the implications for anti-submarine or counter-torpedo situations? Instead of using 33 MJ to send a rod 100 miles, could a heavier, thinner projectile be aimed directly into the sea and go 100 meters before it disintegrated? If we can mount a laser on a 747 why not put a rail gun on a 747 and point the plane down? Or would that blow up the plane? I could also envision a ship with a rail gun simply pointed down, though the design would look exotic.
Well:
- At velocities a railgun uses there is little difference between water and an equal weight of steel armor. So if a long rod penetrator could, for example, go through 2 feet of steel armor it could penetrate only about 20 feet of water before being completely ablated away.
- Railguns have recoil, lasers don’t. The Navy design looks to have about as much recoil as an 8” gun and uses fire-out-of-battery and a long recoil stroke, so there is not much more you can do to decrease the peak forces. You might be able to build a custom aircraft around the gun that could survive more than a couple shots without falling apart, but you probably wouldn’t want to be on board when it was fired.
- You do not want to put a 747 (or any other commercial aircraft) in a vertical dive, you will probably rip the wings off. And it is very likely that it does not have the structural strength to mount dive brakes.
- How would you aim a downward pointed railgun on a ship? Firing a railgun with the muzzle underwater would be like firing a gun when the muzzle is packed with cement.