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Old 02-16-2022, 12:53 PM   #21
Varyon
 
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Default Re: Tech Level news: so, you can buy a Gauss Rifle now

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Originally Posted by Fred Brackin View Post
There's also a secondary issue with the muzzle gasses. In air these mix with the atmosphere quickly but no atmosphere means the gasses go downrange until they hit something. Your gun is already going to be a big hot spot on IR but even if you can stealth that there's nothing to do about those muzzle gasses. From an overhead view they're going to point straight back towards your gun.
Humans are generally going to be unable to see the IR bloom unaided, and if you've got such an aid, I think it would be a rather simple matter for the computer to draw such a line using the heat radiating from your projectile (which should be heating up in either case). The bloom will be easier to detect, but I think it'll be like the difference between a flashlight and spotlight in the night - sure, the latter is technically easier to see where it originates, but you can still see the former just fine (unless you're really far away, but that's what the magnification on your ship's sensors are for). I could be mistaken, and this could be a more significant factor than I'm assuming, however.

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Originally Posted by Ulzgoroth View Post
Bold to assume that the gauss weapons won't generate copious waste heat.
The question is arguably about how much waste heat they generate. Certainly, the current prototype generates quite a bit - I believe in the video where he tested it out on the FW range (not the failed BUG match) he ended up having to wait a bit after shooting a decent number of the larger projectiles at full power, as the device was hot enough that further shooting risked damaging it - but it may well be the case that mature gauss weapons will generate less waste heat than comparable conventional weapons (which, after all, rely on a rather high-temperature reaction to propel their bullets).
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Old 02-16-2022, 01:34 PM   #22
Fred Brackin
 
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Originally Posted by Varyon View Post
Humans are generally going to be unable to see the IR bloom unaided,
They're generally unable to survive in vacuum unaided too.

As to operating heat unless the barrel of the gauss weapon was hot enough to burn any unprotected hands that touched it it is already generating less waste heat.
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Old 02-16-2022, 02:00 PM   #23
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Originally Posted by Varyon View Post
The question is arguably about how much waste heat they generate. Certainly, the current prototype generates quite a bit - I believe in the video where he tested it out on the FW range (not the failed BUG match) he ended up having to wait a bit after shooting a decent number of the larger projectiles at full power, as the device was hot enough that further shooting risked damaging it - but it may well be the case that mature gauss weapons will generate less waste heat than comparable conventional weapons (which, after all, rely on a rather high-temperature reaction to propel their bullets).
High operating temperatures don't have a simple connection to high waste heat. Gauss guns possibly can be a bit more efficient than firearms, but I don't think they'll drop the heat/kinetic energy ratio by a huge factor.
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Originally Posted by Fred Brackin View Post
As to operating heat unless the barrel of the gauss weapon was hot enough to burn any unprotected hands that touched it it is already generating less waste heat.
It's already operating at the energy per shot of a bullet that barely qualifies as a weapon. A .22 short SMG would probably get that hot eventually, but I don't know that it would within a reasonable test.
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Old 02-16-2022, 04:30 PM   #24
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Default Re: Tech Level news: so, you can buy a Gauss Rifle now

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Originally Posted by Fred Brackin View Post
They're generally unable to survive in vacuum unaided too.

As to operating heat unless the barrel of the gauss weapon was hot enough to burn any unprotected hands that touched it it is already generating less waste heat.
Why would the barrel, which is poly carbonate, get that hot? There are no hot expanding gases to contain, essentially negligible friction.

The capacitors on the other hand, I imagine they get rather hot.

The maximum temperature for the PC barrel is 100C, which is rather lower than "to hot to touch" for gun, but it's also 10kg of gun, compared to something like a 2.25kg. I'm almost certain that if you had a 20kg .22 short rifle, it would not overheat terribly fast.

Water is about 4kg a gallon, a Vickers .303 had about a gallon of water in it's jacket and boiled it off after about 2 minutes of sustained fire(450rpm). If you wanted to use water cooling(for some reason), it shouldn't add that much weight to a 5.56 gun, in comparison to a 10kg gun with the capability of a .22short.
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Old 02-17-2022, 10:18 AM   #25
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<shrug> Same way you suppress any large weapon. You use a really large suppressor. It'd be rather inconvenient for the typical muzzleloading mortars.
Is noise suppression even an advantage of EM launchers anyway? If you want a shot to be silent, it has to be [subsonic] which means range and damage is poor, and worse for the smaller sized projectiles people seem to want gauss weapons to fire. If you are shooting hypersonic needles, they're loud. For that matter waste energy even at the gun can emerge as sound as much as heat, so I'm not convinced even dry firing would be all that quiet.
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Old 02-17-2022, 10:22 AM   #26
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Why would the barrel, which is poly carbonate, get that hot? There are no hot expanding gases to contain, essentially negligible friction.
The magnets on the other hand.... The barrel on this thing is essentially just a guide rail right? Plays no part in the actual energy transfer, so no, it doesn't get any hotter than, say, the stock of a chemical slugthrower. The parts that are involved in the energy transfer have to be somewhere though.
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Old 02-17-2022, 10:24 AM   #27
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Is noise suppression even an advantage of EM launchers anyway?
There's some advantage to suppressing the muzzle noise even if the bullet isn't silent, because while sonic boom from a bullet isn't silent, it's not coming from the direction of the gun, so it's harder to determine where the shooter is.
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Old 02-17-2022, 10:36 AM   #28
Fred Brackin
 
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Is noise suppression even an advantage of EM launchers anyway? .
All other things being equal yes. A great deal of the noise of chemically powered slugthrowers comes from the propellent gases. Eliminate the gasses you eliminate the noise that comes from them.

Note that is for coil guns rather than railguns. Railguns have a big plasma arc that will probably be of the same order of magnitude as propellent gasses.

Many people seem absolutely convinced that noise from gasses will be replaced by equivalent noise from something else. I see no reason thsi should be true. soem noise and some waste heat from parts conventional guns don't have? Certainly possible but not necessarily of the same order of magnitude.

Just as note, I was putting the big suppressors on conventional mortars. Possibly just as silly as the Nagant "gas-seal" revolver but probably also jsut as possible.
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Old 02-17-2022, 02:07 PM   #29
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Originally Posted by malloyd View Post
The magnets on the other hand.... The barrel on this thing is essentially just a guide rail right? Plays no part in the actual energy transfer, so no, it doesn't get any hotter than, say, the stock of a chemical slugthrower. The parts that are involved in the energy transfer have to be somewhere though.
Certainly. The GR-1 Anvil stores approximately 3.2kJ of energy, and has an efficiency of 2.8%. So approximately 89-100J ends up dumped into the projectile, leaving approximately 3kJ to become waste heat. That's, not an inconsequential amount, in fact, it's roughly comparable to the energy contained in 1 gram of gunpowder.

1 gram of gunpowder is about 15 grains, which means a .22 short is propelled by about 700ish Joules. Given the high mass of the GR-1, it's not surprising that it doesn't heat up terribly fast, but it also doesn't eject hot brass; and the brass of the ejected cartridge in a conventional firearm carries a great deal of the heat away, and the GR-1 lacks this means of shedding waste heat.

A ruger 10/22 has to absorb about 900J of waste heat in a 2.25kg platform. The GR-1 is absorbing 3100J of waste hit in a 10kg platform. So we're looking at something like 400J/kg of heat for a .22 and 310J/kg of heat for the GR-1, which places it in a comparable range in terms of overheating. These are "meatball math" numbers because there's things to deal with like the aforementioned hot brass being ejected can carrying substantial amount of heat away.
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Old 02-17-2022, 02:48 PM   #30
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Default Re: Tech Level news: so, you can buy a Gauss Rifle now

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Originally Posted by malloyd View Post
Is noise suppression even an advantage of EM launchers anyway? If you want a shot to be silent, it has to be [subsonic] which means range and damage is poor, and worse for the smaller sized projectiles people seem to want gauss weapons to fire. If you are shooting hypersonic needles, they're loud. For that matter waste energy even at the gun can emerge as sound as much as heat, so I'm not convinced even dry firing would be all that quiet.
Pretty much all mortars and grenade launchers are subsonic, as are several small arms calibres including 45ACP, so being subsonic isn't a problem in and of itself - but that just eliminates bullet crack. An EM launcher also has no launch signature - flash or sound - from the firing.
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