8 ms·

Jesus, 110 nautical miles... 110 nautical miles = 126.586 miles That's equivalent to shooting a projectile from: - Baltimore to Philadelphia (102 miles = 88.

Jesus, 110 nautical miles... 110 nautical miles = 126.586 miles That's equivalent to shooting a projectile from: - Baltimore to Philadelphia (102 miles = 88.6356 nautical) - San Francisco to Sacramento (87.3 miles = 75.86 nautical) - Joliet to Champaign (113 miles = 98.1943 nautical) - (almost) Pittsburgh to Cleveland (132.7 miles = 115.31315 nautical) - Tampa to Orlando (84.1 miles = 73.0809 nautical) and so on... Simply amazing how far these things can fire.

tpurves 12y ago
Firing something that distance is easier than hitting anything specific once the projectile gets there. Projectiles must have some kinds of internal guidance system (that works at Mach7) or else the Navy is just going to be slamming random meteorites down anywhere within very large swaths of countryside.
- jballanc 12y ago
  I think you underestimate the military's ability to solve the equations for ballistic trajectories. Don't forget, the very first digital computers existed for the sole purpose of calculating firing tables. They've been at this game a looooong time.
anigbrowl 12y ago
I'm sure they'll show up on ground-based artillery soon enough, and there will be an arms race in the things, because for many theaters they could give one side an overwhelming advantage. Besides the range, the other benefit is cost: railgun launches cost 1-2% of equivalent missile launches, with fewer risks, eg if the enemy bombs your ammo dump, it's much less of a big deal because it's not full of high explosive. These risks matter a lot; in the history of modern naval warfare, the biggest risk to a warship was having its magazine hit, which would usually tear the ship in two.
- andrewchambers 12y ago
  The capacitor banks required are currently much too large.
- lettergram 12y ago
  Ground-based artillery isn't really piratical, it would require a large power draw from a grid, or its own power source. In the case of drawing power from a grid, that wouldn't be practical (or at least, a good idea) in a war time scenario. In the case of having its own power source it would be much to large to be mobile. It works well for ships because many are already nuclear powered and being on the water they have much more mobility.
  - deeviant 12y ago
    I don't really see how being at sea makes the energy requirement logistics easier...
    - ForHackernews 12y ago
      Many naval vessels already have a nuclear reactor onboard.
      - deeviant 12y ago
        Any many land base grids have nuclear reactors of much high capacity, plus hydro power, plus solar, plus fossil fuels... Anyways.
        ForHackernews 12y ago
        Which is great if you happen to be conducting your war in a developed, first-world nation with a solid power grid, and you can count on your enemies to play nice and not disable or degrade that power grid.
        deeviant 12y ago
        There is a great amount of precedent here. Total war was waged in Europe, attempts by all sides were made to disable or degrade the enemies grid, to varying levels of success, but it was never completely suppressed. The same with rail, which I bring up because if you had one of these on a train with electrified track, it would be a pretty significant threat. I mean you could devastate London from Marquise(or from a train rolling down the coast of France.)
- deleted 12y ago
  [deleted]
- tsotha 12y ago
  >I'm sure they'll show up on ground-based artillery soon enough... No it won't, not unless you're going to postulate the existence of some magical power source that fits on a truck and delivers megajoules of power in a fraction of a second.
billyhoffman 12y ago
I wonder what the effective range of this thing actually is because the curvature of the earth is going to come into it when talking about these distances. The curvature is roughly 8 inches per mile, ~1 meter per 5 miles. Something 6 stories tall (~18 meters), like say a large capital ship would be below the horizon if it was 90 miles away. Granted rail guns don't shoot in a straight line but you aren't going to get much ballistic drop in the time it takes a Mach 7 projectile to get to its destination... Mounting the gun higher on the ship would help, but then you are dealing with a very large equal-and-opposite force high above your center of gravity... [EDIT] On second thought, with a velocity of 1.48 miles per second you are talking about 81 seconds of flying time at it maximum range, which is quite long enough for our friend gravity to drop the projectile and "bend" it around the horizon. Holy shit that's pretty incredible.
- jameshart 12y ago
  Naval gunnery has had to take account of that for a long time; pretty sure that 110 mile range is taking the ballistic trajectory into account. It's not like this thing fires the projectile at mach 7 in a straight line, than after 110 nm it suddenly stops.
VikingCoder 12y ago
Duluth to St. Paul is about 125 miles. At Mach 7, that's 85 seconds.
mynameishere 12y ago
The Paris gun could go 81 miles and that was in 1918. I'm assuming the rail guns are much more efficient though. http://en.wikipedia.org/wiki/Paris_Gun http://en.wikipedia.org/wiki/Paris_Gun

tpurves 12y ago

Firing something that distance is easier than hitting anything specific once the projectile gets there. Projectiles must have some kinds of internal guidance system (that works at Mach7) or else the Navy is just going to be slamming random meteorites down anywhere within very large swaths of countryside.

jballanc 12y ago
I think you underestimate the military's ability to solve the equations for ballistic trajectories. Don't forget, the very first digital computers existed for the sole purpose of calculating firing tables. They've been at this game a looooong time.

anigbrowl 12y ago

I'm sure they'll show up on ground-based artillery soon enough, and there will be an arms race in the things, because for many theaters they could give one side an overwhelming advantage. Besides the range, the other benefit is cost: railgun launches cost 1-2% of equivalent missile launches, with fewer risks, eg if the enemy bombs your ammo dump, it's much less of a big deal because it's not full of high explosive. These risks matter a lot; in the history of modern naval warfare, the biggest risk to a warship was having its magazine hit, which would usually tear the ship in two.

andrewchambers 12y ago
The capacitor banks required are currently much too large.
lettergram 12y ago
Ground-based artillery isn't really piratical, it would require a large power draw from a grid, or its own power source. In the case of drawing power from a grid, that wouldn't be practical (or at least, a good idea) in a war time scenario. In the case of having its own power source it would be much to large to be mobile. It works well for ships because many are already nuclear powered and being on the water they have much more mobility.
- deeviant 12y ago
  I don't really see how being at sea makes the energy requirement logistics easier...
  - ForHackernews 12y ago
    Many naval vessels already have a nuclear reactor onboard.
    - deeviant 12y ago
      Any many land base grids have nuclear reactors of much high capacity, plus hydro power, plus solar, plus fossil fuels... Anyways.
      - ForHackernews 12y ago
        Which is great if you happen to be conducting your war in a developed, first-world nation with a solid power grid, and you can count on your enemies to play nice and not disable or degrade that power grid.
        deeviant 12y ago
        There is a great amount of precedent here. Total war was waged in Europe, attempts by all sides were made to disable or degrade the enemies grid, to varying levels of success, but it was never completely suppressed. The same with rail, which I bring up because if you had one of these on a train with electrified track, it would be a pretty significant threat. I mean you could devastate London from Marquise(or from a train rolling down the coast of France.)
deleted 12y ago
[deleted]
tsotha 12y ago
>I'm sure they'll show up on ground-based artillery soon enough... No it won't, not unless you're going to postulate the existence of some magical power source that fits on a truck and delivers megajoules of power in a fraction of a second.

billyhoffman 12y ago

I wonder what the effective range of this thing actually is because the curvature of the earth is going to come into it when talking about these distances. The curvature is roughly 8 inches per mile, ~1 meter per 5 miles. Something 6 stories tall (~18 meters), like say a large capital ship would be below the horizon if it was 90 miles away. Granted rail guns don't shoot in a straight line but you aren't going to get much ballistic drop in the time it takes a Mach 7 projectile to get to its destination... Mounting the gun higher on the ship would help, but then you are dealing with a very large equal-and-opposite force high above your center of gravity... [EDIT] On second thought, with a velocity of 1.48 miles per second you are talking about 81 seconds of flying time at it maximum range, which is quite long enough for our friend gravity to drop the projectile and "bend" it around the horizon. Holy shit that's pretty incredible.

jameshart 12y ago
Naval gunnery has had to take account of that for a long time; pretty sure that 110 mile range is taking the ballistic trajectory into account. It's not like this thing fires the projectile at mach 7 in a straight line, than after 110 nm it suddenly stops.

VikingCoder 12y ago

Duluth to St. Paul is about 125 miles. At Mach 7, that's 85 seconds.

mynameishere 12y ago

The Paris gun could go 81 miles and that was in 1918. I'm assuming the rail guns are much more efficient though. http://en.wikipedia.org/wiki/Paris_Gun http://en.wikipedia.org/wiki/Paris_Gun