67 replies to this topic

[PurpleNinja]

Gauss Rifles are now made of gunpowder.

[The Jove]

CPT Hazel Murphy, on 06 December 2012 - 03:16 PM, said:

Because of this, is why it wouldn't explode. A slug is just that, a slug of solid metal. AC ammo has an explosive charge and warhead and could very likely explode.

A short circuit *can* cause the gauss rifle charging switch to jam on, causing capacitors to overcharge and blow. However, there should be fuses that blow well before cap explosion. But it's a game.

Source: Had that happen on a coil gun I built. Vaporized the fuse.

Edited by The Jove, 07 December 2012 - 03:12 AM.

[The Jove]

Voidsinger, on 07 December 2012 - 12:52 AM, said:

Somebody once worked out in the GURPS tabletop, that the batteries of high tech didn't work, because they exceeded chemical binding energies on discharge.

We know a Gauss rifle throws a 100kg projectile at 1800 metres per second.

K=1/2MV^2

So Gauss Muzzle energy is 162 Megajoules. That's at 100% efficiency.

Anybody going to guess at whether a capacitor system that could release that in such a short time is going to be explosive?

Especially given the Gauss Rifle at 15 tons includes loader, connections, barrel and targeting gear.

Interestingly, if the Gauss Rifle charges over 4 seconds, we are talking about sucking 40MW from the reactor for each Gauss Rifle.

A 100 ton battlemech moving at 48.6 kph has a Kinetic energy of just 9.1Megajoules.

Kind of makes you think doesn't it?

Good things to think about. I'm not sure whether BattleTech-style gaussguns are possible due to various reasons.

However, see here: http://www.ga.com/me...fact_sheet.pdf. General Atomics have a working gun with 32 MJ muzzle energy. They're working on getting it to 10 RPM, so 6 seconds between shots.

A 162 MJ gun doing 4 15 RPM doesn't sound implausible given that we're in a universe with walking giant robots.

[edit: 15 RPM, not 4. Meant 4 second interval between shots. Duh.]

Edited by The Jove, 07 December 2012 - 03:37 AM.

[Voidsinger]

Gauss has fine tolerances either as a series of coils, or rails, or magnets. Whatever you use to get the magnetic field to get the round out. They should be fragile. The short barrel systems used would require nightmarishly powerful magnets and the intense magnetic field generated should interfere with electronics.

They get knocked out of alignment in the slightest, then the weapon should eat itself with the next round or two. Far more so than autocannons.

A GR is much more powerful than anything the US Navy has tested.

The Jove, on 07 December 2012 - 03:22 AM, said:

Good things to think about. I'm not sure whether BattleTech-style gaussguns are possible due to various reasons.

However, see here: http://www.ga.com/me...fact_sheet.pdf. General Atomics have a working gun with 32 MJ muzzle energy. They're working on getting it to 10 RPM, so 6 seconds between shots.

A 162 MJ gun doing 4 RPM doesn't sound implausible given that we're in a universe with walking giant robots.

Yeah, but it is doing 15 rpm, or 1 shot every 4 seconds.

That's why I added the kinetic energy of an Atlas at full speed to the end.

We tend to think the mech movement sucks most of the reactor energy because engine rating is movement. Obviously it is the weapons suite.

Edited by Voidsinger, 07 December 2012 - 03:27 AM.

[The Jove]

Voidsinger, on 07 December 2012 - 03:25 AM, said:

Gauss has fine tolerances either as a series of coils, or rails, or magnets. Whatever you use to get the magnetic field to get the round out. They should be fragile. The short barrel systems used would require nightmarishly powerful magnets and the intense magnetic field generated should interfere with electronics.

They get knocked out of alignment in the slightest, then the weapon should eat itself with the next round or two. Far more so than autocannons.

A GR is much more powerful than anything the US Navy has tested.

True, they should be very fragile. Then again, you could make the same argument about lasers!

Voidsinger, on 07 December 2012 - 03:25 AM, said:

Yeah, but it is doing 15 rpm, or 1 shot every 4 seconds.

That's why I added the kinetic energy of an Atlas at full speed to the end.

We tend to think the mech movement sucks most of the reactor energy because engine rating is movement. Obviously it is the weapons suite.

Sorry, haven't had much sleep. Yes, 15 RPM. I'd say it's still plausible. But like you said, the weapons suite could draw a lot of power from the reactor, which the rules don't actually take into account.

In the end, it's a game which is balanced to be fun. However, it's still fun to ponder whether this technology would be possible IRL!

[Troggy]

The Gauss Rifle is completely plausible. There are already plans for a 63 MJ gun with a 200 MJ power-system. Over a thousand years we should be able to triple this. Cutting the size down to fit on a Mech might be tough, but RT superconductors would fix that (and about a million other problems). They would allow the magnets to be small enough, the capacitors to be very efficient, and would take care of all the heat production, except for air friction. It would also be a small catastrophe if a SC-capacitor physically got broken and shorted to the frame in battle.

Even a sufficiently good ultra-capacitor might allow for a fairly small rail gun. There is nothing in theory which precluding either material or device. Though we are possibly a long way from either. Batteries have a fairly well defined theoretical max energy density (Lithium/Air batteries might be the end), and it is likely insufficient for most of these Sci-Fi devices.

63MJ gun:
http://ieeexplore.ie...r=1398129&tag=1

[Vapor Trail]

200 megajoules of energy every four seconds is 50 megawatts. A two-hundred-fifty megawatt fusion reactor on a mech isn't beyond the realm of believability.

[Feral Goose]

Classic Battletech Total Warefare (2006) Pg. 135

GAUSS RIFLE
If a slot containing any type of gauss ammunition takes a
critical hit, the ammo does not explode, but the hit destroys
the ammo-feed mechanism, rendering the rest of the
ammunition in that slot useless.
A critical hit on the gauss rifle itself destroys the capacitors
that power the weapon, causing a catastrophic discharge
of the capacitor’s stored energy with results identical to an
ammunition explosion. If a gauss rifle takes a critical hit, treat
the result as a 20-point ammunition explosion in the location
containing the rifl e.
Heat: Excess heat does not cause a gauss rifle or its
ammunition to explode