Deployable 'electromagnetic railgun'

TsrJoe

TsrJoe

ACCESS: Top Secret
Senior Member
Joined
2 January 2006
Messages
1,185
Reaction score
2,377
Website
www.facebook.com
Apologies, DELETED POST (please remove from the thread)
 
Last edited:
From defensereview.com with my emphasis
the projectile velocity is so high that the kinetic energy will create all the destructive force you need. As an added bonus, you also need much less projectile mass--the projectile can be much lighter and smaller, and still achieve the same level of destructive force.
Click to expand...
Kinetic energy = 1/2 mv2. so if you make the mass much smaller you make the KE much smaller
unless you assume that the lighter projectile goes faster, which it will if the energy imparted to it by the gun remains constant. But then that is what limits the KE of the projectile. A light projectile will be more affected by air resistance, slowed more quickly and so have shorter range. A much faster projectile will be more affected by kinetic frictional heating so there is a limit to the possible speeds.
Also, for a projectile to have a serious effect on a target, the target must stop it, to convert projectile kinetic energy into absorbed energy which will disrupt the target. A very fast small (tiny in some descriptions) projectile will go straight through.
I'll believe this one when I see it - "it" being a destructive hit on a target, not just a projectile fired fast.
Tell me I'm outdated.
 
Of course, the idea of firing a smaller projectile at a higher speed to achieve the same penetration/destruction isn't news -- the Germans tried it during WWII with the Gerlach (squeeze bore) guns with mixed success -- and it is the priciple behind APDS. The real questions here are: First, can the weapon be made to work and too be light enough to still mount in the kind of vehicles they're talking about? Second, will it be possible to make the projectile deadly and still (a) conserve strategic materials (the Germans ran out of Tungsten to use for the squeeze bore projectiles) and (b) be affordable in an era of declining defense budgets?

Ta for now, Abraham
 
Ranger6 said:
Of course, the idea of firing a smaller projectile at a higher speed to achieve the same penetration/destruction isn't news -- the Germans tried it during WWII with the Gerlach (squeeze bore) guns with mixed success -- and it is the priciple behind APDS. The real questions here are: First, can the weapon be made to work and too be light enough to still mount in the kind of vehicles they're talking about? Second, will it be possible to make the projectile deadly and still (a) conserve strategic materials (the Germans ran out of Tungsten to use for the squeeze bore projectiles) and (b) be affordable in an era of declining defense budgets?

Ta for now, Abraham
Click to expand...

Actually disgarding sabots and squeeze bore rounds couldn't be more different. Their aim might be the same but they achieve it differently. Strategic materials is almost a non-issue as a tank round is a tank round rather the dart is accelerated by chemicals or electricity. Also tungsten didn't have a special connection to the squeeze-bore rounds as the material was used in many types of antitank rounds. The squeeze bore gun was simply a way to accelerate a projectile to a higher speed, as soon as they figured out the sabot it was history.

Back to the high speed thing. While a tank round might go right through a tank (it happened at least once in Desert Storm- an M-1 took out two T-72s with one shot) for the most part it's unlikely. There are a lot of variables to juggle (air resistance, how much material do you want to use, how far can you accurately shoot, etc) but I'm not sure we'll ever see the day of trying to knock out tanks with a BB going 1000 miles/sec. You never know though. I guess you just figure the maximum recoil your vehicle can handle (another advantage of a 70 ton M-1 over a 50 ton T-95), figure the longest range shot you'd need to take and material you'd like to penetrate and work the problem from there. The biggest reason there aren't railguns (or solonoid type guns) is because in order to earn it's way onto the battlefield it needs to have an advantage over the current method. Put it another way the cartridge of the round currently contains the energy. How do you store electrical energy in a way that provides as much energy as the propellent, is as compact, is as simple, and is as cheap? One effort back in the late 80s/early 90s had a turbine-driven electrostatic generator to provide power. You can imagine how that might have added to complexity, cost, weight, and so forth. Rail guns on a ship is a different matter. They already have the electrical capacity (and DDX is going all electric to bump this even higher) so power isn't an issue. In a nut shell, when someone finally developes the proverbial pound of electrons in a little bottle we'll see a revolution (electric everything including planes and railguns on tanks). Until then I'm guessing we won't see railguns on tanks.
 
I have always marveled at the concepts and physics related to this.

While some of our posters already have stated the obvious physics limitations of accelerating even a small body weighing grams to hyper-speeds, isn't there a manageable threshold, a balance of power generation/speed/mass where this technology can stablish a niche, and make possible a viable fielded system before taking the big leap to higher performance?

Isn't this what the ETC (Electro-Thermal-Chemical) Gun is aiming to achieve?

Rafa
 
Rafael said:
I have always marveled at the concepts and physics related to this.

While some of our posters already have stated the obvious physics limitations of accelerating even a small body weighing grams to hyper-speeds, isn't there a manageable threshold, a balance of power generation/speed/mass where this technology can stablish a niche, and make possible a viable fielded system before taking the big leap to higher performance?

Isn't this what the ETC (Electro-Thermal-Chemical) Gun is aiming to achieve?

Rafa
Click to expand...

Actually the limits are your power sources. They were accelerating lexan projectiles to several km/sec 20 years ago. They were also kicking around the idea of railguns deployed in space firing hockey puck shaped KKVs at post-boost vehicles. But again your power source becomes a problem because you won't be powering that sucker with solar cells. :eek:
 
sferrin said:
Actually the limits are your power sources.
Click to expand...
AND the conductivity of the rails, combined with mechanical strength. Pure copper and pure aluminium are excellent conductors but their mechanical strength is deplorable. Fibre reinforcement might do the trick, or mounting the rails on such fibre reinforced bars. Then there's friction... Plenty of limitations to take into account.
 
Simon666 said:
sferrin said:
Actually the limits are your power sources.
Click to expand...
AND the conductivity of the rails, combined with mechanical strength. Pure copper and pure aluminium are excellent conductors but their mechanical strength is deplorable. Fibre reinforcement might do the trick, or mounting the rails on such fibre reinforced bars. Then there's friction... Plenty of limitations to take into account.
Click to expand...

Yeah but if they had the juice they'd FIND a way to use it :) Instead of using Lorenz forces (railgun) you could make a linear motor/superconducting magnets/round magnetically-levitated-in-barrel system. Right now the rest of it (materials, conductivity, etc) is kind of pointless without the power to incentivize.
 
I read some recent naval postgraduate students' design for a future ship including railguns at http://www.nps.navy.mil/tsse/ though they aren't available anymore.
There are some images here though of the design, called SABR:

SABR.png

SABRreactor2.png


The railguns would fire over 100 km. The ship was futuristic otherwise too, having a molten salt reactor power source, podded superconducting motors and all that stuff...
 
sferrin said:
Ranger6 said:
Of course, the idea of firing a smaller projectile at a higher speed to achieve the same penetration/destruction isn't news -- the Germans tried it during WWII with the Gerlach (squeeze bore) guns with mixed success -- and it is the priciple behind APDS. The real questions here are: First, can the weapon be made to work and too be light enough to still mount in the kind of vehicles they're talking about? Second, will it be possible to make the projectile deadly and still (a) conserve strategic materials (the Germans ran out of Tungsten to use for the squeeze bore projectiles) and (b) be affordable in an era of declining defense budgets?

Ta for now, Abraham
Click to expand...

Actually disgarding sabots and squeeze bore rounds couldn't be more different. Their aim might be the same but they achieve it differently. Strategic materials is almost a non-issue as a tank round is a tank round rather the dart is accelerated by chemicals or electricity. Also tungsten didn't have a special connection to the squeeze-bore rounds as the material was used in many types of antitank rounds. The squeeze bore gun was simply a way to accelerate a projectile to a higher speed, as soon as they figured out the sabot it was history.

Back to the high speed thing. While a tank round might go right through a tank (it happened at least once in Desert Storm- an M-1 took out two T-72s with one shot) for the most part it's unlikely. There are a lot of variables to juggle (air resistance, how much material do you want to use, how far can you accurately shoot, etc) but I'm not sure we'll ever see the day of trying to knock out tanks with a BB going 1000 miles/sec. You never know though. I guess you just figure the maximum recoil your vehicle can handle (another advantage of a 70 ton M-1 over a 50 ton T-95), figure the longest range shot you'd need to take and material you'd like to penetrate and work the problem from there. The biggest reason there aren't railguns (or solonoid type guns) is because in order to earn it's way onto the battlefield it needs to have an advantage over the current method. Put it another way the cartridge of the round currently contains the energy. How do you store electrical energy in a way that provides as much energy as the propellent, is as compact, is as simple, and is as cheap? One effort back in the late 80s/early 90s had a turbine-driven electrostatic generator to provide power. You can imagine how that might have added to complexity, cost, weight, and so forth. Rail guns on a ship is a different matter. They already have the electrical capacity (and DDX is going all electric to bump this even higher) so power isn't an issue. In a nut shell, when someone finally developes the proverbial pound of electrons in a little bottle we'll see a revolution (electric everything including planes and railguns on tanks). Until then I'm guessing we won't see railguns on tanks.
Click to expand...
Wrong the U.S. is very fortunate that Russia didn't give Iraq ERA, DU Rounds and Nightvision/Thremal Imaging Equipment because the good ol M1 wouldn't last to long, read why U.S. Army changed from "M829 APFSDS" to "M829A2 and now M829A3"
1. http://en.wikipedia.org/wiki/Kontakt-5
2. http://en.wikipedia.org/wiki/Monkey_model
3. http://en.wikipedia.org/wiki/T-72
 
TheRightHand said:
Wrong the U.S. is very fortunate that Russia didn't give Iraq ERA, DU Rounds and Nightvision/Thremal Imaging Equipment because the good ol M1 wouldn't last to long, read why U.S. Army changed from "M829 APFSDS" to "M829A2 and now M829A3"
1. http://en.wikipedia.org/wiki/Kontakt-5
2. http://en.wikipedia.org/wiki/Monkey_model
3. http://en.wikipedia.org/wiki/T-72
Click to expand...


Where's the ROFL icon when you need it?
 
Naval ships and rail guns

Will the development of Electro Magnetic Rail Gun (EMRG) technology for naval ships lead to the return of mostly gun naval warship designs, perhaps a modern interpretation of early 20th century battlecruiser or battleship designs?
 
Re: Naval ships and rail guns

Under the assumption that they can work as advertised then I believe we will would see a return to long range naval bombardment. But it is a big if 1) the technology works, 2) it works and it is cheap, 3) the platforms where they are mounted are reasonably priced, 4) they fire for long periods and require little maintenance and 5) despite all this there is the research dollars today to continue research over the next ten plus years.
 
Re: Naval ships and rail guns

Given the probable length of a big rail-gun, and assuming BAE Systems etc really have figured out how to solve rail erosion, IMHO, you may be talking a dedicated ship, like those early missile-cruisers that had a 'production line' through their heart to assemble and feed projectiles onto the fore-deck launcher...

( I'm wondering if BAE Systems have recycled that machinery to rebuild launcher after each salvo... ;- )

Uh, and you'll need 'smart shells' that only have to be lobbed into general area then perform 'terminal guidance'. Saves swinging the ship so carefully to aim it, like a carrier having to 'turn into wind'...
 
Re: Naval ships and rail guns

Note that current railguns are planned to have broadly the same size and weight as the 155mm Advanced Gun System. Se my post here:

http://www.secretprojects.co.uk/forum/index.php/topic,1672.msg95014/highlight,rail.html#msg95014

RP1
 
Re: Naval ships and rail guns

RP1 said:
Note that current railguns are planned to have broadly the same size and weight as the 155mm Advanced Gun System. Se my post here:

http://www.secretprojects.co.uk/forum/index.php/topic,1672.msg95014/highlight,rail.html#msg95014

RP1
Click to expand...

RP1, is your paper concerning EMRG and warship design available online?
 
Re: Naval ships and rail guns

RP1 said:
Note that current railguns are planned to have broadly the same size and weight as the 155mm Advanced Gun System. Se my post here:

http://www.secretprojects.co.uk/forum/index.php/topic,1672.msg95014/highlight,rail.html#msg95014
Click to expand...
Railguns have always interested me. From what I understand however, their efficiency is kind of low, in that they drop more energy that needs to be disposed off as waste heat in the own ship than kinetic energy delivered to the target. The efficiency being so poor mostly due in the low speed range of the acceleration part. Do you see any improvement in a two stage system, where a conventional gun accelerates the shell in the first stage? It would give higher efficiency, reduce waste heat, shorten barrel length, but would probably be a lot more complicated. Is this assessment right?
 
Re: Naval ships and rail guns

Interesting. Railguns do have an "injector" or whatever you call it, I guess usually a compressed air gun.
 
Re: Naval ships and rail guns

RP1, is your paper concerning EMRG and warship design available online?
Click to expand...

Not yet. An edited version will appear on the DRC website soon. I'll post a link when it is complete.

Regards,

RP1
 
Re: Naval ships and rail guns

Mach 8 Rail Gun Shot - from Danger Room

http://www.wired.com/dangerroom/2010/12/video-navys-mach-8-railgun-obliterates-record/
 
Re: Naval ships and rail guns

Would be nice to see where it impacted, although I suspect they would have just let it impact the ground somewhere in the testing area.
 
Re: Naval ships and rail guns

The latest firing of the Navy rail gun. It looks completely tame on the firing side. However, the other side of the barrel is the gateway to hell itself....

http://www.youtube.com/watch?feature=player_embedded&v=-uV1SbEuzFU
 
Re: Naval ships and rail guns

"Velocitas Eradico". Appropriate enough, methinks.
 
Re: Naval ships and rail guns

USNI Proceedings had an interesting article recently about just what rail guns can do and their benefits. Without going into the whole article, one of the most salient points made was comparing how we do things now with how they could be with a rail gun.

Basically, they can do most of what we now do with cruise missiles and the like (yes, including submunitions, terminal homing, etc.), out to the limits of their range, and they travel faster and are more resistant to countermeasures. The article points out we have over the years evolved to a situation where we have cheap launchers firing very expensive munitions. With a rail gun, like most naval cannons, you have a quite expensive launcher. But, you get to use it over and over again and you're shooting a very cheap munition. Plus, you can shoot lots of them. Carrier folks never liked to admit it, but over the course of an 8 hour day a BB could put a lot more ordnance on target than could a CVN, the limitation of course was range.
 
Re: Naval ships and rail guns

In that video, the 'bullet' doesn't look very stable. I wonder what that does for accuracy.
 
Re: Naval ships and rail guns

Umm, the projectile has big flat plate on the end of it to keep it from going far downrange. That's not going to make for a very stable flight path. Also the fork shaped armature doesn't detach which is also bad for stability, it would for a warshot. Right now the job is all about making the gun part work at all.
 
Re: Naval ships and rail guns

Are plans still moving towards integrating railguns on Flight III Burkes someday? Unless the Flight III will be a significantly different (and larger) from the current Flight IIA, this sounds like quite a challenge.
 
Re: Naval ships and rail guns

Hobbes said:
In that video, the 'bullet' doesn't look very stable. I wonder what that does for accuracy.
Click to expand...

As the guy in the link below explains they've just been using that as a test round and various companies have developed other rounds. He pimps a round designed by Boeing too.

http://vodpod.com/watch/6134181-new-rail-gun-rounds-zip-through-steel-at-1-mile-a-second
 
Re: Naval ships and rail guns

In general, it's better to pay attention to the railgun rounds that look like Hugo Awards. Those are the real ones that fly fast for miles. The older bricks are just proof rounds with no aerodynamics.
 
Re: Naval ships and rail guns

Navy Selects JHSV Trenton For Railgun Shot In 2016


The Navy will fire the electromagnetic railgun for the first time at sea from the fifth Joint High Speed Vessel, the Trenton, in a demonstration next summer, according to the program manager.
Capt. Michael Ziv, railgun program manager, announced the selection of the Trenton for the at-sea demonstration April 14 at the Navy League's Sea-Air-Space exposition.
During the demonstration, the railgun will fire a GPS-guided Hyper Velocity Projectile at a fixed over-the-horizon target, Ziv said. The test will validate system performance models for the dynamic, multimission railgun, he said.
The test will take place on the Eglin Air Force Base maritime test range in late summer 2016.
The Navy eventually sees fielding the railgun, a futuristic technology that fires projectiles using electricity instead of chemical propellants, on Zumwalt-class destroyers. -- Lara Seligman
Click to expand...

http://insidedefense.com/node/168767
 
Re: Naval ships and rail guns


"Beware of the concussion! Beware of the concussion!"

Oswald Cabal
 
Re: Naval ships and rail guns

I had no idea they had developed a GPS guidance system for a railgun projectile. I wonder if the G profile of a railgun may be more benign than a conventional explosive driven shell. If the EM acceleration is applied over the length of the rail that would reduce the G loads significantly. In some pictures it looks like all the cabling is near the breach so it seemed it was an instantaneous discharge.
 
Re: Naval ships and rail guns

If the EM acceleration is applied over the length of the rail
Click to expand...


My understanding is that is one of the main advantages, and that yes the maximum acceleration could be lower than a conventional gun. The cabling arrangement is to allow the barrel to be traversed and elevated.


RP1
 
Re: Naval ships and rail guns

G-loads are one thing, but the railgun EMF would matter more to the chip. You would have to design a projectile that is opaque to the EMF, but transparent to GPS signals and anything a targeting sensor might use.
 
Re: Naval ships and rail guns

It's not a huge problem, in part because the electronics don't have to be working during the launch. The test shots next year are supposed to include some GPS guided rounds.

http://news.usni.org/2015/04/14/navsea-details-at-sea-2016-railgun-test-on-jhsv-trenton
 
A couple of general railgun questions:


1: The video Triton posted regarding the General Atomics weapon ("Blitzer") shows a ROF of what looks like nearly 100rpm for short bursts.
https://www.youtube.com/watch?v=-xeHfxzjThQ


Given the stated rate of fire for the BAE weapon (10RPM) this may well be artistic license, but I do wonder if the General Atomics weapon has a higher ROF. Its projectiles seem to be around 30-40mm in caliber as opposed to the 100mm or so of the BAE weapon so it very well might. Does anyone know if this is the case?


2: Is 10 RPM really sufficient, especially for AAA fire? The Mk 45 fires twice as fast and is considered quite slow.


3: Related to the previous question, is the greater ceiling on this weapon's rate of fire the heat build-up or power generation?


4: If it is heat, couldn't the ROF per mounting be greatly increased for the same power by using twin or triple mounts? (Fire one. While it's cooling, redirect power to the other one or two.)


5: These high velocity weapon may not be very good for indirect fire, and at lower velocities most of the kinetic effect is lost. However, there is mention on the NAVWEAPS page...
http://navweaps.com/Weapons/WNUS_Rail_Gun.htm
...of an explosive warhead. Is this related to the HVP program?
http://news.usni.org/2015/06/01/navy-researching-firing-mach-5-guided-round-from-standard-deck-guns
Also, can the railgun fire a projectile at lower velocity to lob such explosive shells in indirect mode? (A 33 pound shell is minimalist for fire support but its on a par with a 4 inch shell or the French 100mm.)


6: For the General Atomics weapon, would the projectile be more effective in the anti vehicle/point target role by simply disabling the Shrapnel mechanism and having it hit as a unitary round, or would at least two different types of projectile be needed as seems to be the case with the BAE weapon?
 
Brickmuppet said:
A couple of general railgun questions:


1: The video Triton posted regarding the General Atomics weapon ("Blitzer") shows a ROF of what looks like nearly 100rpm for short bursts.
https://www.youtube.com/watch?v=-xeHfxzjThQ


Given the stated rate of fire for the BAE weapon (10RPM) this may well be artistic license, but I do wonder if the General Atomics weapon has a higher ROF. Its projectiles seem to be around 30-40mm in caliber as opposed to the 100mm or so of the BAE weapon so it very well might. Does anyone know if this is the case?
Click to expand...
Its very much a conceptual video, so take any and all details with a grain of salt. As to the Rate of Fire specifically, at present the size of the projectile is not as much of a limiting factor as are for instance the capacitors which dump power into the rails. The Navy and the DoD more broadly have expressed interest in rapid-fire railguns as defense weapons and that is certainly a direction they hope to go as rail weapons mature, but at present I don't think either of BAE/GA has anything near that ROF on their working hardware.
2: Is 10 RPM really sufficient, especially for AAA fire? The Mk 45 fires twice as fast and is considered quite slow.
Click to expand...
But the rounds travel much flatter, farther, and faster. They may also be guided, certainly that appears to be an objective. Everything is a tradeoff.
3: Related to the previous question, is the greater ceiling on this weapon's rate of fire the heat build-up or power generation?



4: If it is heat, couldn't the ROF per mounting be greatly increased for the same power by using twin or triple mounts? (Fire one. While it's cooling, redirect power to the other one or two.)
Click to expand...
The recharge/discharge of the capacitors is one of the largest stumbling blocks as I understand it. Heat generation is a concern, to be sure.
5: These high velocity weapon may not be very good for indirect fire, and at lower velocities most of the kinetic effect is lost. However, there is mention on the NAVWEAPS page...
http://navweaps.com/Weapons/WNUS_Rail_Gun.htm
...of an explosive warhead. Is this related to the HVP program?
http://news.usni.org/2015/06/01/navy-researching-firing-mach-5-guided-round-from-standard-deck-guns
Also, can the railgun fire a projectile at lower velocity to lob such explosive shells in indirect mode? (A 33 pound shell is minimalist for fire support but its on a par with a 4 inch shell or the French 100mm.)
Click to expand...
Railguns can absolutely fire at lower power settings. And yes, the Navy wants a common high velocity projectile that can be place in a railgun or 5" round.
6: For the General Atomics weapon, would the projectile be more effective in the anti vehicle/point target role by simply disabling the Shrapnel mechanism and having it hit as a unitary round, or would at least two different types of projectile be needed as seems to be the case with the BAE weapon?
Click to expand...
Remains to be seen how the rounds evolve, and what if any different varieties are put into service simultaneously. At present, though, they are still testing.
 
"But the rounds travel much flatter, farther, and faster. They may also be guided, certainly that appears to be an objective. Everything is a tradeoff."

Yep. Big difference between dumb rounds out of a Mk45 turret and what are essentially guided missiles fired out of a railgun.
 
http://www.popularmechanics.com/technology/gadgets/a18123/mad-scientists-build-250-pount-portable-diy-railgun/
 

Similar threads

Please donate to support the forum.

Back
Top Bottom