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The Navy plans to fire 5-inch diameter non-explosive projectiles from deck-mounted railguns:
The Navy plans to fire a high-speed, long-range rail-gun Hypervelocity Projectile from its deck-mounted 5-inch guns to destroy enemy drones, ships, incoming missiles and even submarines, service officials said.
The effort is led by a special Future Naval Capability program.
Navy officials say the program is leveraging commercial electronics miniaturization and computational performance increases to develop a common guided projectile for use in current 5 inch guns and future high velocity gun systems. The HVP effort will seek to increase range and accuracy of the 5-Inch Gun Weapon System in support of multiple mission areas, service developers told Warrior.
Developed initially for an Electromagnetic Rail Gun next-generation weapon, The Hyper Velocity Projectile, or HVP, can travel at speeds up to 2,000 meters per second when fired from a Rail Gun, a speed which is about three times that of most existing weapons.
BAE Systems Hyper Velocity Projectile. 5-inch gun. Found at NBF.
Related: U.S. Military Increasing Development of Directed Energy Weapons
U.S. Navy's New Mach 6 Electro-Magnetic Railgun Almost Ready for Prime Time
(Score: 2) by KilroySmith on Wednesday October 25 2017, @09:11PM (25 children)
So they're thinking about shooting a round designed for Mach-6 speeds out of a legacy deck gun at conventional speeds, and they expect that legacy deck gun to be quickly and precisely aimable so they could hit drones and incoming missiles?
The actual Navy fact sheet:
https://www.onr.navy.mil/en/Media-Center/Fact-Sheets/Hypervelocity-Projectile.aspx [navy.mil]
doesn't mention drones or missiles; that seems to be hyperbole from the article's author.
Seems more like the defense contractor making the "Hyper Velocity Projectile" is trying to figure out a way to sell more of them...
(Score: 2) by c0lo on Wednesday October 25 2017, @09:20PM (9 children)
Well, if you shoot enough of them, some may ht the target. You only need to buy enough shooters.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by bob_super on Wednesday October 25 2017, @10:36PM (8 children)
That's my main question: how many rounds before you need to change the barrel ?
(Score: 2) by frojack on Wednesday October 25 2017, @11:24PM (6 children)
Thousands. The sabot can be made of non-abrasive material.
Actually less wear and tear on the barrels than regular rounds which have to engage the rifling in the barrel in order to spin them.
No, you are mistaken. I've always had this sig.
(Score: 4, Informative) by c0lo on Thursday October 26 2017, @02:41AM (5 children)
Correction needed. Wikipedia on railgun design [wikipedia.org] says:
And here's how a railgun firing looks like [wikipedia.org] - I suspect the energy consumed in this one show to be in the MJ range, perhaps higher.
---
My thoughts - the hyper-velocity comes with some costs:
1. conductivity - currents are in the thousands of amps, the ohmic losses (heat) goes with the square of the current;
2. until one gets high temperature superconductors, I don't think anything else but copper can do. Which is is a mecanical problem: copper is very maleable thus low resistance to friction wear and deforms easily - do I need to draw the picture what will happen with a very minor deformation when it is hit at well in excess of 2000m/s? Can you imagine the repulsive force developeped between the two rails?
3. friction during the sliding of the projectile over rails. Friction will be lower for lower area of contact between the projectile and the rails, but... low area of contact means high current densities, which means the contact area overheats and the current->kinetic energy efficiency drops. Higher area of contact means lower loss do the resistivity but the friction increases.
4. huge magnetic field variations in a short time - losses in eddy currents induced in anything metallic around? How about the arcing due to the extreme voltages imposed by the necessary magnetic field variation?
Those huge copper bars, mounted as rigid as possible in some very strong frame - preferable non-metallic -... expect them to heat quite high during the firing and the wear to be non-negligible.
One thing that can be done to increase the lifetime of the rails - use soft metals for the projectile casing, with low melting/boiling point and as good conductivity as possible - aluminium would be a good candidate.
The effect that I'd expect - in the first part of the acceleration, the ohmic heating in the contact area will be quite high. I expect the superficial layer of the sabot to melt (or even evaporate), "lubricate" the rails and decrease the wear on the rails without a significant drop in the contact conductivity.
But... doing so may decrease the accuracy, I'm not sure they can afford the trade-off - what good is a long-lived long range/high energy cannon if the accuracy is shit?
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 3, Informative) by frojack on Thursday October 26 2017, @03:22AM (2 children)
Uhmmm, in case you need help with your reading comprehension, this isn't about shooting a railgun.
Its about shooting a sabot jacketed projectile out of a 5 inch gun with the same (or similar) powder charge that they fire conventional shells.
They aren't converting these guns to rail guns, they aren't going to shoot anything all that much faster out of the barrel than they already shoot, (beyond the speed improvement they would get by firing a lite weight projectile).
Its no more barrel wear, and because its a sabot round (google that) your don't even have to engage the refiling in the tube with anything except plastic, the projectile has its own fins for spin and stabilization.
Go read about the 5 inch MK 45 gun: https://en.wikipedia.org/wiki/5"/54_caliber_Mark_45_gun [wikipedia.org]
No, you are mistaken. I've always had this sig.
(Score: 2) by c0lo on Thursday October 26 2017, @04:43AM
Reading time is what was missing.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 0) by Anonymous Coward on Friday October 27 2017, @03:15PM
The error is in the summary, where it says "The Navy plans to fire 5-inch diameter non-explosive projectiles from deck-mounted railguns."
(Score: 0) by Anonymous Coward on Thursday October 26 2017, @04:04PM (1 child)
Ignoring your misreading of the issue (see other comment)...
How about a disposable conductive liquid oozing from the rails? The obvious is a really thin layer of seawater. The projectile glides on the water. The water boils off, removing the heat as it does.
Accuracy is no trouble with guided ammo, which I think these are. (slightly, like a guided artillery or mortar shell)
(Score: 2) by bob_super on Thursday October 26 2017, @04:28PM
> The obvious is a really thin layer of seawater. The projectile glides on the water. The water boils off,
Leaving behind salt, which you have to wash off quickly before it destroys everything.
(Score: 2) by c0lo on Thursday October 26 2017, @02:44AM
A very few [soylentnews.org]
Which is good for the business, isn't it?
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by MichaelDavidCrawford on Wednesday October 25 2017, @09:44PM
That was the cover story of some defense rag after the Iraqis tore an American Navy ship a new asshole.
Yes I Have No Bananas. [gofundme.com]
(Score: 2) by edIII on Wednesday October 25 2017, @10:34PM
It had me at "submarines". I mean, if you a deck mounted gun that can shoot high projectile velocities at submarines, wouldn't you get one?
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 3, Informative) by frojack on Wednesday October 25 2017, @11:20PM (2 children)
Also glossed over is the "guided projectile" bit. Steerable after firing, either with its own microwave radar or return echo from the ship's radars.
There are sabot rounds, the actual warhead is sub-caliber (smaller than 5 inch), and carried in a discarding sabot. It then flicks out its own fins for stabilization spin and steering.
See this 2015 article about what this round can do
https://foxtrotalpha.jalopnik.com/watch-the-navys-hyper-velocity-projectile-rip-through-t-1705064652 [jalopnik.com]
Also this round effectively triples the range of a 5 inch gun.
https://www.nextbigfuture.com/2017/10/us-navy-hypervelocity-projectiles-tests-tripled-range-of-5-inch-guns-and-with-superaccuracy.html [nextbigfuture.com]
No, you are mistaken. I've always had this sig.
(Score: 2) by edIII on Wednesday October 25 2017, @11:27PM (1 child)
Yeah, but can it really shoot stuff under the water accurately? The TFA mentions submarines and that just sounds plain fanciful.
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 2) by frojack on Thursday October 26 2017, @12:31AM
Yeah, I don't know, seems a corner case at best.
I suppose if you can steer it in flight, you could fire it over a shallow sub that your sonar has detected, and then dive them into the water at the steepest angle you could muster.
I doubt the sub would be at much risk if it was a couple hundred feet down.
No, you are mistaken. I've always had this sig.
(Score: 2) by frojack on Wednesday October 25 2017, @11:27PM (3 children)
There are other stories (see my post below) that do mention drones or missiles.
These things are steerable after being fired.
No, you are mistaken. I've always had this sig.
(Score: 2) by KilroySmith on Wednesday October 25 2017, @11:46PM (2 children)
"These things are steerable after being fired."
That's not the same as "can hit drones or incoming missiles".
(Score: 4, Insightful) by MostCynical on Thursday October 26 2017, @01:35AM (1 child)
"When they miss, we can blane the operator, not the design.."
"I guess once you start doubting, there's no end to it." -Batou, Ghost in the Shell: Stand Alone Complex
(Score: 1) by Booga1 on Thursday October 26 2017, @03:38PM
The comment and the username align so well...
(Score: 2) by Runaway1956 on Thursday October 26 2017, @12:35AM (5 children)
I think you've fastened on the wrong problem. A 5"54cal is amazingly agile. I've been pretty intimate with a couple of them. We routinely shot missiles down with them. Our own, actually, because when those old Tartar missiles got confused, the largest metal object on which to home was our own ship.
The problem that I'm seeing is, how in hell do you turn a solid metal barrel into the electrical guides for a rail gun? You use an insert in the barrel? Some kind of jacket over the barrel? Uhhhh - have we forgotten that the barrel of a naval gun stays right there, on deck, for the life of the ship? That is, in a hostile, salt laden environment? I foresee serious cleaning and corrosion problems. Ultimately, I foresee an unreliable and unusable weapon.
Better to just remove the old dual purpose gun, and replace it with the new gun, IMO. Since most destroyers have two guns, remove one, and keep one old one. No matter what current doctrine says, I suspect that sometimes, the one weapon will suit the situation better, and sometimes the other.
(Score: 2) by mhajicek on Thursday October 26 2017, @12:46AM (4 children)
I believe they mean to push it with conventional chemical propellants.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 2) by Runaway1956 on Thursday October 26 2017, @02:36AM (3 children)
So - we have a standard 72 pound charge, pushing a saboted round that maybe weighs 30 pounds? Mmmm. Maybe, but I don't think we attain that ultra-velocity that a rail gun gets. We only get a faster, lighter round, which would be good in some situations, and possibly bad in other situations.
Time for work - if I remember, maybe I'll do some searching on this tomorrow.
(Score: 2) by mhajicek on Thursday October 26 2017, @03:44AM (2 children)
I believe that's exactly what they plan to do, but with the bonus that the round is guided. Do any of the standard rounds have guidance?
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 2) by Runaway1956 on Thursday October 26 2017, @02:21PM (1 child)
Ours did not. I can't say for sure, but it shouldn't be terribly hard to put at least some "dumb" guidance into a warhead - depending on what purpose that warhead serves. A penetrator might be very hard to modify, whereas an HE would allow a lot of room to work in. I have read of "smart" shells in larger guns, but I've never been close enough to inspect anything like that.
Well - wait a second. Just how "dumb" can guidance be, and still be called guidance? Anti-aircraft rounds have proximity sensors. That's enough guidance to tell the shell what the opportune moment is to detonate. Very dumb, but also more effective than using timers. But, none of our shells could alter their courses. Gunplot did all the heavy lifting, prior to firing.
(Score: 2) by mhajicek on Thursday October 26 2017, @05:07PM
I think what you're describing would classify as "fusing", and guidance would refer purely to steering or course correction. I recall reading about how proximity fuses reduced the number of rounds needed to down an aircraft by an order of magnitude in WWII. That was pretty impressive tech for the day. There's also a guided .50 BMG round now.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek