5 replies to this topic

[Tordin]

I have had these questions in mind for a long time now and I wonder what kind of ammo/ energy/ missile are used in BT. Regarding real - life equilent, tabletop and MWO/ MW/ MC.

1: What is the caliber of the different ballistic weapons such as LBX, AC/UAC, Gauss rounds, RAC etc?

As I recall the MG for the IS, at least in MWO are 50 cal. I imagine Ac2 are like, 60 mm?

2: Any known equalient from real life or what so ever for lasers, plasma and particle weapons?

MY Guess there got to be some really high powered ion, kinda lasers with great lenses and artificial diamonds to focus them beams? Reasons for different colors and such?

3: And what about missile types, sizes and contents?

[GroxGlitch]

1) Canonically, the caliber of ballistic weapons varied between manufacturers in Battletech, something we don't see in MWO. The AC/# is a given damage rating, which all cannons were built to do within a 10 second interval (one turn in TT). From memory, I might be off on the numbers, but there was one 200mm AC/20 which did all it's damage in one hit (Pontiac something-or-other, believe it was carried on the stock Hunchback), then another manufacturer had one that fired off literally a 20mm hundred round burst. Both had the same effect on target, but were radically different in their approach.

The same general rule goes for Gauss Rifles, though they generally more or less all do the same damage on target, which means manufacturers would likely just trade off slug mass and muzzle velocity in some ratio (at least in an arbitrary damage number sense)

1a) IIRC even machine guns vary in caliber. Some IS ones were .50 to .80 caliber, quite commonly, but some went higher and lower. An old image knocking around on my hard drive of a technical drawing of a Clan Timberwolf lists the machine guns installed on the Prime as "Nathan Browning M2A4 .80 Caliber Anti-Personnel Machine Gun"s, so presumably the Clans used MG loadings similar to the Inner Sphere.

2) Unfortunately, real world energy weapons are virtually non-existent, per my knowledge, in the same vein as what we see in the BattleTech universe. No real world analogue exists for the Particle Projection Cannon, though lasers do exist and are fairly plausible. As far as I know, the exact functioning mechanism behind BattleTech lasers is never stated, but from their mass and energy output, I would assume them to be Free Electron Lasers (https://en.wikipedia...-electron_laser) Free Electron Lasers can reach very high energy outputs, and while I don't have the exact numbers, some forum-goers smarter than I have crunched the numbers and they're pretty big.

As far as colours go, pew pew sci fi lasers. Most weaponized lasers would, though I'm not sure on this, want to be tuned to the infrared wavelengths to maximize transfer of thermal energy to the target (which is particularly easy to do with FELs, for the record); were this the case, you wouldn't even see them directly, though you might see a path of superheated, perhaps ionized air in the laser path in an atmospheric environment. If someone more knowledgeable on the subject would fact-check me here, I'd greatly appreciate it.

3) I can't give you anything on missiles, as far as realism or lore goes. As far as I can tell, they'd have to be unrealistically small to stuff as many of them as they do into a cramped, armored BattleMech chassis, while being handled by an autoloading mechanism, chambered, and launched. Apparently, according to Sarna, LRMs and SRMs are made of some metal-high explosive composite which allows the whole missile to be the warhead (wat?). How they don't detonate when they're so much as handled stiffly, much less launched or battered around by impacts to the armour, I have no clue.

Edited by GroxGlitch, 15 July 2015 - 07:52 AM.

[Strum Wealh]

Most BT/MW MG bullets are ~20mm (~0.79 inches) or less in diameter.
Most BT/MW Class-2 AC shells are 30mm (1.18 inches) to 40mm (1.57 inches) in diameter.
Most BT/MW Class-5 AC shells are 50mm (1.97 inches) to 80mm (3.15 inches) in diameter.
Most BT/MW Class-10 AC shells are 80mm (3.15 inches) to 100mm (3.94 inches) in diameter.
Most BT/MW Class-20 AC shells are 120mm (4.72 inches) to 200mm (7.87 inches) in diameter.
Most BT/MW Gauss Rifle slugs are 100mm (3.94 inches) to 300mm (11.81 inches) in diameter.

Autocannons in BattleTech are cassette/magazine-fed burst-fire weapons, where each salvo (that is, each pull of the trigger) fires a set of individual shells; the number of shells varies from as few as three (3) to as many as one-hundred (100), with most ACs firing three (3) to ten (10) shells per burst.

"Ardan ran a hurried check on his Victor's main armament. The right arm Pontiac 100 autocannon had the best chance of scoring a crippling hit on the Thunderbolt, but he was afraid that his swim in the mud might have fouled its feed mechanism. The autocannon was a devastating weapon. It fired high-speed, rapid-fire streams of explosive, armor-piercing shells from cassettes or carousels fed into the gun one at a time by a complex and occasionally balky autoloader mechanism. Each cassette held 100 shells, and by a widespread but commonly accepted looseness of terminology, each cassette was itself considered to be one round. One cassette round was already loaded. Nineteen more were stored in the autoloader chamber high up in his Victor's right torso. He would have to use that single round carefully, because if the loader jammed, he would not get another chance." - The Sword and the Dagger, ch. 13

Machine Guns in BattleTech behave similarly to the autocannons; the main differences are in terms of the type of projectile fired (MGs fire solid bullets, while ACs fire high-explosive shells), weapon calibers (MGs typically have bores of 20mm or less, while ACs typically have bores of 30mm or more), and burst sizes (MGs typically fire larger numbers of individual projectiles than ACs).

Gauss Rifles - named in reference to the 18th century German mathematician Carl Friedrich Gauss, who described the mathematics for the electromagnetic effects underlying their operation - are large, weaponized coilguns, a type of electromagnetic accelerator that is not to be confused with railguns. Unlike the other ballistic weapons, Gauss Rifles fire a single large projectile - a solid, ovoid or spherical mass of Nickel-Iron alloy - with each pull of the trigger.

A listing of calibers for specific examples of ballistic weapons, with sources, can be found here.

Edited by Strum Wealh, 01 December 2015 - 09:19 AM.

[Tordin]

Great stuff guys. Alot of interesting info, gotta read some more into it. Thanks

[SnagaDance]

IIRC lasers are sometimes referred to by (lense) diameter. With 5cm being used for Medium Lasers and 8cm for Large Lasers (no idea on the small ones).

[Strum Wealh]

Lasers are a fairly well-understood technology, and there are several real-world examples of laser weaponry:

"THEL" (Tactical High Energy Laser)




ZEUS-HLONS


COIL laser system (mounted on the Boeing YAL-1 Airborne Laser Testbed)


"LaWS" (Laser Weapon System)




Rheinmetall 50kw "HEL" (High Energy Laser)


There is a reason why real-world laser weapons look more like stubby telescopes than WWII naval guns or MBT cannons.

Specifically: conventional firearms & artillery can gain some advantages (and disadvantages) from having relatively long barrels (see here and here), but lasers are not subject to any of the same considerations that make barrel length beneficial (most of which are related to how the propellant charge burns & the expansion of the propellant gases, and how those translate into effective range & accuracy-at-range) AND would still suffer the negative aspects (increased mass, increased difficulty to traverse & elevate, increased production expense, and others) if a long barrel were attached.

So, there is no advantage to long-barreled designs like those of the classic Vulture illustrations, and why real-world militaries (and, for MWO, PGI) make laser weapons without the superfluous barrels.

BattleTech lasers likely use all of the different lasing techniques (e.g. "semiconductor lasers", "solid state lasers", "fiber lasers", "free electron lasers", and even "gas lasers" to account for things like the Clans' chemical lasers), as there are so many different makes & models of lasers in service throughout the Inner Sphere.

For laser sizes:

• Chapter 08 of Initiation to War confirms that the Intek Medium Lasers on the right arm of the Axman have 4cm (that is, 40mm) apertures.
  
• Chapter 29 of Decision at Thunder Rift confirms that the Martell Medium Laser on the right arm of the Shadow Hawk has a 6cm (that is, 60mm) aperture.
  
• Chapter 25 of Heir to the Dragon confirms that the Martell-manufactured Hellion-V Medium Lasers on the Atlas have 5cm (that is, 50mm) apertures.
  
• Chapter 25 of Heir to the Dragon also confirms that the Thunderbolt A5M Large Laser in the left torso of the Zeus has a 10cm (that is, 100mm) aperture.

Edited by Strum Wealh, 15 July 2015 - 11:45 AM.