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Old 03-08-2018, 12:49 PM   #1
hal
 
Join Date: Aug 2004
Location: Buffalo, New York
Default ULTRATECH guass weapon system design rules?

Hello Folks,
Does anyone have a design system they've been using for use with describing the ultratech guass weapons?

Using Doug's spreadsheet formulas - I get a 442.9 grain (28.7 grams) bullet moving at 2650 feet per second, will produce 12d6+0 damage with a 10:1 aspect length (Dart) bullet. The presumption is that the dart is made of a tungsten/Titanium core mixed with lead etc for a rough density comparable to depleted uranium. That works out to a bullet that weights roughly .06 lbs per shot for those who wonder.

As such, using the Ultratech rules for bullet damage, high tech bullets improve the damage from 12d6 to 12d6(2) or 12d6(3) with Armor-Piercing Enhanced Penetrator designation.

If that's the case, what is the energy required as input assuming 25% efficiency (per other threads on Gauss guns and batteries etc)?

Yes, the stats I'm going for mimic the stats in the book, but I wanted to see just what would go into a design system for getting gauss weapons made where one could create the bullet stats first, determine the velocity you wanted the bullet to travel at the muzzle - and then determine how many shots each battery type would enable the user to fire. I'd like to be able to design some alternative diameters other than 7mm for the sniper rifle or the 4mm weapons given in the book. For instance, a 5.56 bullet made not as a dart, but as a simple bullet might be interesting to see what happens. Yes, I'd suspect that the weapon's accuracy might suffer - but then again, it would be interesting the explore the options - something a design system would be NICE if existed.

If necessary, I'll go to GUNS GUNS GUNS design rules - but then use the spreadsheet developed by Doug to determine actual damage values etc.

Question for you out there who know answers...

Is there anything to keep from having a sabot that actively interacts with a barrel as it exits by propulsion via electromagnetic means? In other words, assume you have a sabot whose only purpose is to be comprised of material that allows the magnetic fields to function/grip the bullet. Suppose that plastic were soft enough that it could be forced through the barrel much like a lead bullet is propelled through a conventional fire arm. Could not rifling in a gauss gun barrel, acting upon the sabot material itself - spin the bullet as it exits, and then fall away once it passed the end of the barrel?

Just curious.

If such a concept is viable - it would prove to be interesting in its secondary effects. For instance, anyone who wants to police up their firing vantage point, would need to pick up the sabot halves after the shot is fired. Crime scene investigators might be able to develop forensics that measure the residual magnetic field imprint on the plastic halves - on the presumption that no two gauss rifles/guns leave the same pattern. That's probably NOT a real science issue (after all, if one can "dial a shot" and use variable level power - would that affect magnetic field strengths and such?) But it is sort of interesting to figure out the ramifications of the new technology approaches. Might not the same forensic techniques that work on bullets - also work on the sabot sleeves after they leave the barrel?

Also - if the Chinese Navy gets a working prototype Rail gun for their navy within say, the next five years - does that make their weapon a TL 9 weapon in late TL 8 society, or does it mean that Rail Gun Technology should be deemed a TL 8 innovation, and Gauss guns that are man portable should be considered TL 9?
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Old 03-08-2018, 01:16 PM   #2
AlexanderHowl
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Default Re: ULTRATECH guass weapon system design rules?

You actually need to use a bronze sabot around a nickel steel bullet with a tungsten core. Bronze possesses the lowest friction coefficient of any metal and possesses the third highest heat capacity of any common metallic alloy. Tungsten possesses a relatively high friction coefficient and possesses a relatively low heat capacity, meaning that tungsten will actually vaporize in a gauss weapon before bronze even softens.

Depending on the design of the projectile, the sabot should be designed to not separate until impact (which is different than normal sabots) in order to prevent the bullet from melting in the air. When the projectile hits, the bronze sabot will peel away while the nickel steel bullet will crack the armor of the target. The tungsten core will then perforate the structure of the target.
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Old 03-08-2018, 02:02 PM   #3
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Default Re: ULTRATECH guass weapon system design rules?

Honestly, you probably don't want a sabot if you can avoid contact with the rails in a railgun; you could just make the rails helical and use a maglev-type configuration to float the projectile in the weapon. Current could be transmitted by plasma (this is one layout, minus the helical rails, that has been proposed for railguns).

For coil guns, you can just use the magnetic field itself to impart a spin on the projectile. This, again, is probably more efficient than a sabot because you are not losing a ton of energy to friction and you don't have to contend with the heat buildup in the gun, either. After all, circuits generally don't like heat.

More efficient than either of these is using a fin-stabilized projectile, or if the round is large enough, an actively-stabilized and possibly guided projectile. If you don't like fins, a lot of current research is being done in the use of piezoelectric and memory-materials to create deformable control surfaces for everything from entry vehicle heat shields to airplane wings that deform instead of having control surfaces. This could be extended to the surface of a projectile, if miniaturized (which, frankly, is probably easier than making an airliner's wing deform)

With all of that said, this is ultra-tech, so you can really just make up whatever material you want. Some bioferrous smoothium-balongite nanocomposite discarded sabot totally works if you need to justify it!
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Old 03-08-2018, 03:36 PM   #4
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Default Re: ULTRATECH guass weapon system design rules?

It is almost impossible to avoid contact with the rails though, at least in any man portable system, as your weapon can only be so large. Bronze is just a nice logical solution.
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Old 03-08-2018, 06:23 PM   #5
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Default Re: ULTRATECH guass weapon system design rules?

Excuse my ignorance if this comes off as totally off base, I'm a layman through and through, but do you really need bronze and depleted uranium approximating alloys for effective manportible gauss weaponry?

I understand the desire for the optimal weapon, but this doesn't seem to address longistics and price points for a consumer market.
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Old 03-08-2018, 06:43 PM   #6
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Default Re: ULTRATECH guass weapon system design rules?

Rahleu? Had some on his blog.
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Old 03-08-2018, 07:41 PM   #7
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Default Re: ULTRATECH guass weapon system design rules?

Bronze is essential for man-portable systems or else the heat from the friction will broil the user around the same time that it melts the barrel. Depleted uranium is unnecessary with a tungsten core. If you do not care about penetration, you can just use a bronze sabot around a nickel steel bullet (probably (2) rather than (3) armor penetration).
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Old 03-08-2018, 09:39 PM   #8
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Default Re: ULTRATECH guass weapon system design rules?

Quote:
Originally Posted by AlexanderHowl View Post
Bronze is essential for man-portable systems or else the heat from the friction will broil the user around the same time that it melts the barrel. Depleted uranium is unnecessary with a tungsten core. If you do not care about penetration, you can just use a bronze sabot around a nickel steel bullet (probably (2) rather than (3) armor penetration).
Does Bronze posses the ideal characteristics to not melt the gun or are their better, but much more expensive options?
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Old 03-08-2018, 10:46 PM   #9
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Default Re: ULTRATECH guass weapon system design rules?

Bronze possesses the lowest friction coefficient of any metallic alloy so, when combined with its relatively high (for a metal) specific heat, it ends up winning the prize. It also radiates heat much faster than the majority of metal alloys, so you do not have as much heat retention as with other materials (so the physical armature should be made of bronze as well, though the magnetics have to be behind the armature). Now, with larger weapons, you can avoid contact with the rails, so you can use more effecient processes and get to higher velocities, but I think that you are going to be using a lot of bronze for man-portable systems.
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Old 03-09-2018, 06:21 AM   #10
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Default Re: ULTRATECH guass weapon system design rules?

Quote:
Originally Posted by Minuteman37 View Post
Does Bronze posses the ideal characteristics to not melt the gun or are their better, but much more expensive options?
It's worth noting that specific heat isn't the only - or necessarily the most important - factor. Heat doesn't transfer in bulk instantaneously, so you should really be at least as concerned with the heat resistance of the material. This is inversely proportional to a material's heat conductivity, k. Furthermore, the contact time in the weapon should be excruciatingly small if the gun is reasonably sized and functional. So even if the heat tranfer rate is high, the time of transfer in the gun is similarly small. All in all, there is a very good chance that you really don't need - or necessarily want.

For comparison, bronze has a thermal conductivity of 16 W/m-K Titanium ranges between 19 and 23; carbide ceramics can be as low as 0.65, and silica aerogel (not suitable for other reasons) is only 0.017.
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