36 replies to this topic

[SethAbercromby]

I'm just going to skip most of your nonsense now.

martian, on 07 August 2016 - 01:16 AM, said:

Unfortunately, that's not how BattleTech PPCs work. They are explicitly described as "vaporizing tons of armor" (TechManual). Sorry, but you are wrong again.

The vaporization comes after the fact. The initial impact punches its way trough armor with massive kinetic energy concentrated to a very small surface area. Even with kinetic energy dispersion, this kind of impact is why KEPs are our modern armor killers because it surpasses the dispersion rate by several margins and simply punches through. The heat melts the plates from the inside after the fact which would theoretically make a PPC a nearly guaranteed kill when it goes through armor and scores an internal hit.

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And "That explosive damage is largely ineffective against ablative armor" is uncorrect too, as the example of the Arctic Wolf - specifically designed 'Mech only with missile armament - very clearly proves. (Technical Readout: 3060)

And each missile still does only one point of damage per hit. BT missile systems are 'mass over class', simply overwhelming armor with enough quantity to eventually sand it off.

Zacharias McLeod, on 07 August 2016 - 01:25 AM, said:

Someting about modern Laser Weapons.

Lasers have been used as part of anti-missile installments for years now, and for that purpose they are good enough. The problem is that because you always have more energy building up in the weapon than whatever you're hitting it with, laser weapons get exponentially larger in order to handle the internal heat.

The reason an industrial laser cutter that only needs to melt a few millimeters of a steel sheet is quite compact but one that can shoot down a missile is the size of a car is not 'because it looks cool'.

[martian]

SethAbercromby, on 07 August 2016 - 01:46 AM, said:

I'm just going to skip most of your nonsense now.

So you really ran out of your arguments so soon? My quotes of basic BattleTech books are nonsense, but your presumptions are okay?

By the way, I am still waiting for your Sarna link regarding that AC-20 firing 200 kg shell.

SethAbercromby, on 07 August 2016 - 01:46 AM, said:

The vaporization comes after the fact. The initial impact punches its way trough armor with massive kinetic energy concentrated to a very small surface area. Even with kinetic energy dispersion, this kind of impact is why KEPs are our modern armor killers because it surpasses the dispersion rate by several margins and simply punches through. The heat melts the plates from the inside after the fact which would theoretically make a PPC a nearly guaranteed kill when it goes through armor and scores an internal hit.

And do you have a BattleTech source for this?

SethAbercromby, on 07 August 2016 - 01:46 AM, said:

And each missile still does only one point of damage per hit. BT missile systems are 'mass over class', simply overwhelming armor with enough quantity to eventually sand it off.

Oh boy, you are wrong again.

Arctic Wolf's missiles are more effective than you think, as is the 'Mech itself, considering that it's used by three Clans.

Plus, there are bigger missiles in BattleTech universe too.

[SethAbercromby]

martian, on 07 August 2016 - 02:26 AM, said:

So you really ran out of your arguments so soon? My quotes of basic BattleTech books are nonsense, but your presumptions are okay?

What arguments? You're using the same argument you have been from the start. 'The material says X, so you're wrong'. I am getting bored of it, that's why I'm just not even going to bother any more. Wake me up when you have something more interesting to go by.

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And do you have a BattleTech source for this?

It's called science and inductive reasoning. You might've heard of it.

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Arctic Wolf's missiles are more effective than you think, as is the 'Mech itself, considering that it's used by three Clans.

6x SRM6, 2x SRM4.

That is the literal definition of mass over class. You can like missile systems all you want, but at the end of the day the individual missiles are only effective in bulk.

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Plus, there are bigger missiles in BattleTech universe too.

You can always go bigger. Doesn't mean that it becomes the norm or particularly practical. If SRMs are the ideal standard short range explosive warhead, then you can assume that to be at the top of its tech and 2 points of damage for what should be an armor killer isn't particularly impressive.

As I said, that kind of discrepancy is why HEP is either too good for its own universe, or the guns perform a lot worse than they could if they used KAP rounds.

[martian]

SethAbercromby, on 07 August 2016 - 02:43 AM, said:

What arguments? You're using the same argument you have been from the start. 'The material says X, so you're wrong'. I am getting bored of it, that's why I'm just not even going to bother any more. Wake me up when you have something more interesting to go by.

We are in the "BattleTech Discussion" section. I am discussing BattleTech and its fictional universe. But since you are mostly ignoring BattleTech and its setting ...

SethAbercromby, on 07 August 2016 - 02:43 AM, said:

It's called science and inductive reasoning. You might've heard of it.

Yes, I have heard about them.

In your posts you are cherrypicking one or two facts that you like and conveniently ignoring the rest of the BattleTech setting.

SethAbercromby, on 07 August 2016 - 02:43 AM, said:

6x SRM6, 2x SRM4.

That is the literal definition of mass over class. You can like missile systems all you want, but at the end of the day the individual missiles are only effective in bulk.

One ton of SRM ammo can remove 180-200 points of armor.
One ton of Autocannon ammo can remove 90-100 points of armor.

It means that SRMs are actually more effective than ACs. It's interesting because in your previous post you said that explosive damage weapons are ineffective.

SethAbercromby, on 07 August 2016 - 02:43 AM, said:

You can always go bigger. Doesn't mean that it becomes the norm or particularly practical. If SRMs are the ideal standard short range explosive warhead, then you can assume that to be at the top of its tech and 2 points of damage for what should be an armor killer isn't particularly impressive.

Thank you that you have finally bothered to find the damage value of SRMs. In your previous post you declared that they do 1 damage.

SethAbercromby, on 07 August 2016 - 02:43 AM, said:

If SRMs are the ideal standard short range explosive warhead, then you can assume that to be at the top of its tech and 2 points of damage for what should be an armor killer isn't particularly impressive.

To remove 20 points of armor in short range, you can take AC-20 weighing 14 tons. Or you can take five SRM-2s weighing 5 tons.

At least it's not Rheinmetall L/55 that would barely scratch armor of an enemy 'Mech.

Edited by martian, 07 August 2016 - 03:40 AM.

[SethAbercromby]

martian, on 07 August 2016 - 03:37 AM, said:

To remove 20 points of armor in short range, you can take AC-20 weighing 14 tons. Or you can take five SRM-2s weighing 5 tons.

The most efficient missile system for use with armored vehicles is probably the LAHAT system, a relatively cheap delivery system costing 'only' $25,000 to manufacture the 10kg warhead compared to a 25kg (depleted uranium) $10,000 APFSDS anti-tank round or $78,000 Javelin which is used by infantry forces, but on a per-tonnage basis, it is still highly expensive.

However, missiles are much more vulnerable to defensive systems and changes in armor performance. Missiles still operate under the same basic principle as almost 40 years ago, that is funneling a shaped blast into a target. The more advanced armor becomes, the more complex missiles have to become to compensate, increasing their manufacturing costs several times over.

KEPs on the other hand are rather consistent in their pricing, most of which is dependent on the costs of high-density metals like depleted uranium or tungsten. The BT universe assumes an abundance of high-density metals for the sake of its armor being cheap to produce and replace, so the same could be assumed for such rounds. However, the manufacturing costs in the BT Universe are very lopsided. Assuming 25kg 120mm shells fired in 8-round bursts, each shell costs 250 C-Bills to manufacture, while one of the 100 10kg missiles loaded in a ton of missile ammo cost only 270 C-Bills to manufacture.

This sets us in front of a few abnormalities. The Lore claims that the missiles are completely made of a 'metal composite/high-explosive mixture' which turns the entire warhead into its payload while somehow still retaining armor-piercing capabilities. Ignoring the fact that this would actually decrease armor-piercing capabilities since there would be no liner to actually focus that explosive power onto the point of impact, this would strongly beg the question why it is so expensive to manufacture the much simpler tank shells, regardless of whether they would be KEP or HEAP. From a per-projectile basis, the two are very similar, 2.5 points of damage for each shell and 2 damage for each missile, but when comparing system tonnage and overall costs, it would almost never make sense in-universe to ever design a Mech around an AC/20.

As for tonnage itself, all ballistics in the BT universe are grossly oversized. The entire assembly of an L/44, that is gun mount plus barrel, is less than 4.5 tons (the L/55 is a bit heavier due to the extended barrel, but I couldn't find an exact number). Missile systems are very light since the missiles themselves do a lot of the hard work themselves, so the 1-3 tons for an entire assembly on a 'Mech or Vehicle seems pretty likely to me. You could argue that the ballistics would add some tonnage to support a magazine-style loader or ammunition belt capable of high rates of fire, but the limitation of contemporary tank guns is more the strain put on the barrel. Since the lore appears to assume that the weapons are largely impervious to normal wear in pristine condition, we can safely assume that the AC/20 barrel can handle the extreme the heat and friction of 48 120mm rounds being fired off every minute, or one round every 1.25 seconds.

A more realistic weight would probably be around 8 tons, most of which being dedicated to thermal sleeves, shock compensators and the complex autoloader.

In real life, missiles are used for being more reliable and having a higher effective range than tank shells (when fired from a tank or helicopter) or their ability to be carried by infantry and light vehicles, but tank shells are favored for being much cheaper to produce and not having any counters outside of proper armor plating while still boasting a high effective range.

The BT AC/20 is ridiculously oversized while having laughable range. Either would have already been a decent-enough balancer but both is just silly. Anyway, digressing here.

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At least it's not Rheinmetall L/55 that would barely scratch armor of an enemy 'Mech.

As I already said, the shells used by ACs are not magic bullets. If weight stays mostly the same you can only go up with velocity, but that is faced with very strong diminishing returns the further up you go (that is more speed requires exponentially more propellant). Pretending the hypothetical 25kg 120mm shells are functionally identical to the ones fired by an L/55, the damage output of the AC/20 is of course much higher due to the much higher rate of fire, but the L/55 will still do about 4 damage each turn for less weight than an AC/2.

However, this does again put into question what kind of machine guns we're using because at this point the bullets are probably going at almost the speed of atmospheric re-entry.

[Karl Streiger]

Interesting but I have calculated the damage of 1 Point of BT damage using explosives. Calculation was 3 years ago basing on MW3 RPG; TechManual, and Time Of War RPG and ToW Companion

Based on this approach: ~ TNT ~ C8 ~ BT
So we have not 34kJ but 9.2 MJ per point of BT armor


You should also keep in mind that your calculations are based on todays knowledge - and we don't have so much zero-g processing nor are we able to consturct stable fusion engines nor is impossible to have a p+p+p+p fusion engine that is not a sun.

So for example 15 points of BT armor might be 15x9.2MJ = 138 MJ but maybe the energy needed for each additional point of damage is exponential increasing. So you may need 9.2 MJ for 1 BT but a total force of 20 MJ to remove 2 BT points.
But its ablative and not penetration resistant so again a complete different approach.

Edited by Karl Streiger, 15 August 2016 - 01:17 AM.

[SlightlyMobileTurret]

martian, on 06 August 2016 - 01:08 PM, said:

British Army has actually favored HESH ammo against armored targets such as tanks?

Trust me, the only guys that keep HESH around are the British Army and the Indian Army, and it's for "bunker busting", nowadays.

Blows up concrete and reinforced structures really well, but not great against armour.

[Nebfer]

A few things to note:
Current 120mm tank rounds like the M829A3 is about 25kg complete, has a MV of 1,555m/s and has a projectile that is 10kg, of which 3kg of that is the sabot. Though other rounds have different stats.

B-tech weapons seem to be heavy at first but with a few assumptions, can easily be quite light.
1st off look to their real world naval weapons, the 5 inch gun on US Warships is around 20 tons and has a rate of fire of about 25 RPM. While real life current Tank guns are about 3-4 tons they generally do not include robust auto loaders capable of reloading multiple rounds in under 10 seconds (if we assume a 120mm based AC-20 to fire 10 rounds in a burst, then it's firing 60 120mm shells a minute), nor do they include items like connections for heat distribution, nor do I believe they Generally included Fire control and aiming systems (dose that 3 or 4 tons included the turret traverse gear? I do not believe so). Also B-tech weapons likely have more capable recoil systems than current tank guns, who only have to deal with the recoil of one round every 5 to 15 seconds, rather than a entire multi round burst in a few seconds.

Weight is also likely taken up because the weapon we use in game is a generic system, an 100mm based autocannon is likely to be lighter than one that is 203mm, but the game abstracts that into a single system. not to mention mounting gear that allows it to by the game standard on any unit with the slots and mass, in just a few hours (I'de like to see you try to stuff the Russian 125mm gun in an Abrams and get it to work in under 6 hours).


Using B-tech MGs is an odd way to go for weapons performance, though I suppose one could start anywhere. Mostly as MGs can give you a vastly different value than other weapons. Also many B-tech MGs are 20mm, with even reference to 30mm ones, though 12.7mm based MGs are not unknown.
One issue with chemically propelled rounds is how much of that say 200kg shot is cartridge case and powder vs the shell...

As such the Gauss rifle is a much easier system to get data, though Gauss slugs have their own issues...
By roughly 3 to 1 the most commonly stated velocity is Hypersonic for Gauss rifles (though I have seen people insist that the lesser velocity's are more correct, such as mach 2.2 and 1,000m/s or the most common of them "supersonic"...)
and is a 125kg slug made from nickle iron, older novels commonly described it to be a cannon ball (or melon shaped), newer ones seem to have shied away from that description a bit however.

Battletech auto cannons are commonly described to fire HEAP, with the novels typically mentioning a DU tip to them.

B-tech energy weapons are a sore point for some, But by in large B-tech energy weapons in the novels commonly cause rivers, streams, rivulets, ect of armor to flow freely from the unit, some times entire heaps of armor is sent crashing down in bubbling heaps (in exact amounts that correspond to to the weapons damage rating in game).

The Novels do commonly mention a static interference with PPCs.


One of the older B-tech forums calks for B-tech weapons damage, which done by a poster called Fallguy (no longer posts on the B-tech forums), came up with ~6.25 megajoules (per point of dmg) for energy weapons, and ~12.5 megajoules for Ballistics (I generally do not recall what he got for missiles, though I believe it's not to much different from energy weapons I think, the old forum posts are largely gone, and my notes doesn't have that bit).

Cray (the guy who wrote much of tech manual): often notes that to melt 30kg of Iron would take about 30 megajoules IIRC, and 30kg of iron is about what he figures for the steel portion of B-tech armor.

For simplistic sake he went with 30kg of Iron and 30kg of CBN (Cubic Boron Nitrite), which is the main components of B-tech armor (well super hard steel that is radiation treated and aligned for maximum strength). I believe B-tech steel is intended to be one of thoughs monocrystalline armor steels which was a bit of a thing in sci-fi before carbon nanotubes took off in the mid 90s.

Though how they also managed to get steel to accept diamond fibers with FF armor with out it affecting the steel (or the diamonds) I believe is beyond our capability's.

Cray is also noted as saying B-tech lasers are by in large mega melta heat rays (noting the many counts of melted armor flowing like mini rivers in the novels)

SethAbercromby, on 07 August 2016 - 07:03 AM, said:

The BT AC/20 is ridiculously oversized while having laughable range. Either would have already been a decent-enough balancer but both is just silly. Anyway, digressing here.

like I said earlier, modern tank guns Generally do not have rates of fire in the dozens or hundreds of rounds per minute, even the ones with autoloaders

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However, this does again put into question what kind of machine guns we're using because at this point the bullets are probably going at almost the speed of atmospheric re-entry.

Funny that, a B-tech MG has an effective range of 108km in space (time of flight at most 60 seconds, likely less, considering that your engaging targets that an accelerate at upwords of 11Gs)...

For refrence here's a Conventinal fighter

Specs are taken from what the rules say and the units TRO entry
Name: Meteor Heavy Strike Fighter; Model A (Alt Names; DCMS= Inseki, TCAF= Bat Hawk)
Date in service: 2665
Operator: Every one (Fed Suns introduced)
Mass: 45 tons
Empty weight: 38 tons
Max Take off weight: 54 tons
Power plant: GM 225 Atmo-Fusion rated at 1,765kN (396,832lbf)
Acceleration: 4Gs (5/8)
Climb Rate: 600m/s or more
Service Celing: 35,000 meters (114,800 feet)
Max Low altitued speed (0-17km): 1,800kph (1,125mph) Mach 1.47 or 2,160kph (Mach ~2) depending on the rules used
Max High altitued speed (18-35km): 3,240kph (2,015mph) Mach 3.02
Fuel load: 3 tons (+4.5t external)
Max Ferry Range: 34,560km (86,000km with external)
Max Endurance: 197 to 960min (672 to 2,400min with external)
Armor mass: 2.5t
External ordnance: 9t
Radar Range: 10,000km (well ASFs have that in space, no known info on atmo)
Weapons: 1x Mydron Model B AC-10 w/2t ammo, 2x Holly SRM-4 w/ 2t ammo

The Novels mention a number of ASFs flying at hypersonic speeds as low as 500m above the ground (one wrong move and splat...).
Also the Mydron Model B autocannon is mentoned to be an 80mm in the novels.

The Fighter can out climb, acelrate, fligh higher and faster (and sustained to boot) than a F-22 Raptor (I belive it's top speed is around mach 2.3, ~1,500mph or ~2,400kph), it also has a longer endurance, Oh and it has armor, somthing few modern craft have (I do not think expanding rod warheads are going to be as efective on somthing that genraly needs AT weapons).

[SethAbercromby]

Nebfer, on 17 August 2016 - 01:11 AM, said:

Using B-tech MGs is an odd way to go for weapons performance, though I suppose one could start anywhere.

Quite the opposite. If you want to estimate anything based on real-life performance, then you have to choose something in that world that most closely mirrors our own. I chose the 12.5 because one of the primary purposes of the MG in BT lore is to engage infantry and with ammo divided into 200 packages, it seemed reasonable to assume that they would aim to keep at least a semblance of a high rate of fire for suppressive purposes. What is also to consider is that BattleMech MGs are very short and do not use long high-velocity barrels like 20 or 30 mm anti-air cannons we use today, so you need a significantly higher portion of propellant to get them to an effective velocity. That is if you don't just use the same projectile but with more propellant, though in that case you are still faced with increasingly diminishing returns. I would assume the actual gain in penetrative power would be a relatively minor one to what I had calculated.

Regarding your example with Naval cannons, what you need to consider is that the weight usually also includes turret armor and control systems. The fire control system mounted in BattleMechs is a very primitive one, if it even has any notable impact on high-caliber ACs and is not disregarded completely in favor of not having the recoil knock the Mech over. My ballpark estimate was based around two tons for the barrel, one ton for the thermal sleeve, five tons for the auto-loader and one ton in stabilizing equipment. You can give two perhaps three tons for general assembly and mountings if you like, but I still don't really see 14 tons happening. You also have to consider that the auto-loader on a naval cannon has to load a shell with enough propellant to be effective at tens of kilometers, compared to a modern tank gun's 4 km and AC20s apparent 200 meters.

There is a very large difference between a mechanism that has to lad a 25 kg object compared to one that has to do the same for a 40 or even 50 kg object. That kind of exponential growth is why we have settled with 120 mm as our caliber of choice because it is currently at just the right balance of power, weight and the complexity of the mechanisms required to operate it. The real limitation of our modern weapons is also not really the mechanical element but a material one. As i mentioned before, firing a projectile creates heat both by ignition of the propellant as well as friction of the projectile or sabot with the barrel. If you fire too many times in rapid succession, that heat will cause the metal of the barrel to soften and deform as gravity pulls down on it. We could probably very easily build a mechanism that is capable of feeding 60+ shells per minute into a tank gun, but the barrel would not survive even half of it. Best case you're shooting holes into the ground right in front of you. Worst case, the deformation causes irregularities in the barrel that cause a shell to get stuck, which would likely end up blowing up the entire construction as the energy of the propellant has nowhere to go to.

Recoil is a very significant thing, but by that logic so is excess heat. A Large Laser capable of melting 500 kg of whichever armor composition you prefer in less than 10 seconds will also cause enough excess heat to melt itself and whichever body part it was mounted on alongside with it the instant it was fired. If you want to argue that half of the AC/20s weight is just to combat the intense recoil (which would actually fit well with my ballpark estimate), then I would call significant amounts of BS on why you can have a Large Laser operate at only 5 tons, much less a Medium one at 1.

I like having the novels a little separate from the 'science' of the lore. While I deeply respect each of the authors, most of them do often disregard realistic depictions in favor of a more dramatic effect, which is perfectly fine for their purposes, but we can't build consistent physics without consistent rules.

Unfortunately the rules are hardly consistent when it comes to putting any real scientific comparison between individual weapons even when just using the baseline rules, but the MG really is what breaks the entire universe. Those 2 points of damage either make every other weapon system look hilariously weak, or turn the MG in the most overpowered piece of technology in that universe (aside from Lasers that is).

Edited by SethAbercromby, 22 August 2016 - 06:08 PM.

[Nebfer]

SethAbercromby, on 22 August 2016 - 06:02 PM, said:

Quite the opposite. If you want to estimate anything based on real-life performance, then you have to choose something in that world that most closely mirrors our own. I chose the 12.5 because one of the primary purposes of the MG in BT lore is to engage infantry and with ammo divided into 200 packages, it seemed reasonable to assume that they would aim to keep at least a semblance of a high rate of fire for suppressive purposes. What is also to consider is that BattleMech MGs are very short and do not use long high-velocity barrels like 20 or 30 mm anti-air cannons we use today, so you need a significantly higher portion of propellant to get them to an effective velocity. That is if you don't just use the same projectile but with more propellant, though in that case you are still faced with increasingly diminishing returns. I would assume the actual gain in penetrative power would be a relatively minor one to what I had calculated.

Note: B-tech MGs have a range in space of 108km (or atmospherically 3km), while one could argue the effect of that, at it's simplest B-tech MGs are not quite equivalent to a M2HB, Also ignoring that ~12mm based MGs are not exactly the most common in the fluff (or at lest when associated with specific systems/units). In the TROs I do not recall seeing a 12mm based MG a few references to 20mm and even one reference to a 30mm (scorpion tank fluff).

Heck in the RPG companion they introduce a set of "Vintage" (infantry) weapons, vintage as because they where largely stopped being produced by the 2200s, around that time they where replaced by more modern weapons. So in effect these "Vintage" weapons can be argued to represent "modern real life" weapons.

They Generally suck compared to their B-tech counter parts, and in some cases would struggle to penetrate some of the current house infantry armors.

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Regarding your example with Naval cannons, what you need to consider is that the weight usually also includes turret armor and control systems. The fire control system mounted in BattleMechs is a very primitive one, if it even has any notable impact on high-caliber ACs and is not disregarded completely in favor of not having the recoil knock the Mech over. My ballpark estimate was based around two tons for the barrel, one ton for the thermal sleeve, five tons for the auto-loader and one ton in stabilizing equipment. You can give two perhaps three tons for general assembly and mountings if you like, but I still don't really see 14 tons happening. You also have to consider that the auto-loader on a naval cannon has to load a shell with enough propellant to be effective at tens of kilometers, compared to a modern tank gun's 4 km and AC20s apparent 200 meters.

1) Modern warships largely have effectively zero armor, at best some splinter protection with Kevlar, their Gun houses are basically fiberglass or sheet steel (or aluminum), with what you listed (Barrel 2t, sleeve 1t, feed system 5t, stab gear 1t, mounting 3t) that is 12 tons, 2 more tons is not that hard of a stretch, also your forgetting one very important thing, the system is a generic one that represents weapons ranging from 100mm to 203mm, with 120mm being common, while 12 tons is perhaps generous for a 120mm, would it be so for a 200mm one? I happen to know that for example the USN 5 inch 64 gun is apx 23 metric tons with it's mounting, but the 155 gun on the Zumwalts is in the 100 ton range on it's mounting, the prototype LW 8 inch gun was 79 tons, and that was just the rotating gunhouse (gun house AKA turret, full mass was 102 tons, the gun by it self was 9 tons, do not know if that includes items like the breach)

So 14 tons for a AC-20 is perfectly fine, 12 tons for the AC-10, is perhaps a bit excessive but even then you can find some wiggle room.

2) B-tech Weapons ranges are deceptive, Total warfare it self mentions their reduced for play ability (at B-tech scale 3km will be ~100 hexes, and will take up the better part of 100 square feet of playing space, and ranges that far generally make it quickly turret tech), Also you mention later that theirs a lot of contradictions, that is true, it is as such with ranges, sure a bog standard PPC only has a range of "540m", but yet can nail a ASF flying at mach 1 at 2km altitude, or a MG can wipe out a infantry platoon that is 90m away from it while their standing on a level 200 hex (that's 1,200 meters of elevation), as the game dose not really track elevation. Also that AC-20 in space has a effective range of 108km, no difference between the weapon, after all a AC-20 on a Dropship, fighter or small craft has the same range on the ground as a battlemech, but the second it lifts off it has two options one is the aforementioned 108km (via capital scale), the 2nd is atmospheric scale (though both are used in conjunction with planets), which provides a range of 3km (or 4.5/6km if you use hexes)...

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There is a very large difference between a mechanism that has to lad a 25 kg object compared to one that has to do the same for a 40 or even 50 kg object. That kind of exponential growth is why we have settled with 120 mm as our caliber of choice because it is currently at just the right balance of power, weight and the complexity of the mechanisms required to operate it. The real limitation of our modern weapons is also not really the mechanical element but a material one. As i mentioned before, firing a projectile creates heat both by ignition of the propellant as well as friction of the projectile or sabot with the barrel. If you fire too many times in rapid succession, that heat will cause the metal of the barrel to soften and deform as gravity pulls down on it. We could probably very easily build a mechanism that is capable of feeding 60+ shells per minute into a tank gun, but the barrel would not survive even half of it. Best case you're shooting holes into the ground right in front of you. Worst case, the deformation causes irregularities in the barrel that cause a shell to get stuck, which would likely end up blowing up the entire construction as the energy of the propellant has nowhere to go to.

You can build rapid fire 120mm autocannons, many modern 5 inch naval guns have a rate of fire in the 30 or 40 rounds per minute per barrel, the 76mm Super rapid has a rate of fire in the 120 per minute range (dose not self destruct), the modern french 100mm guns have a rate of fire of around 80 RPM, it also is 22 metric tons.

As for why we use 120mm tank guns, is not strictly because of limits of autoloaders and their systems, it's actually the human element, 120mm rounds are about the largest that can be easily man handled repeatedly, and about the largest one can comfortably fit in the cramped confines of a tank, and that 120mm is more than up to the tasks required for tanks currently (already some countries are looking into bigger calibers to handle the next wave of armor).

One last thing here, Modern tank guns like the M256 have a barrel life of around 1,500 shots, though that in it self is a lie, because modern APFSDS rounds are counted at around 3 to 5 rounds per shot, the Heat rounds however are fired at a lower pressure and velocity and thus have a 1 round per shot count on barrel life. So an Abrams barrel might have to be replaced after firing a few hounded rounds. A B-tech autocannon quite likely has a lot longer barrel life, than the M256, which can impact the weight of the barrel a bit.

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Recoil is a very significant thing, but by that logic so is excess heat. A Large Laser capable of melting 500 kg of whichever armor composition you prefer in less than 10 seconds will also cause enough excess heat to melt itself and whichever body part it was mounted on alongside with it the instant it was fired. If you want to argue that half of the AC/20s weight is just to combat the intense recoil (which would actually fit well with my ballpark estimate), then I would call significant amounts of BS on why you can have a Large Laser operate at only 5 tons, much less a Medium one at 1.

Funny you take the range of 270mm for a AC-20 seriously but you can not handle a laser having the energy to melt/vaporize/whatever even though that is exactly what it says happens. I.e. you can not go off and reinvent B-tech weapons, B-tech lasers are routinely stated to melt hundreds of kg of armor.


Techmanual out rite states 3 PPCs can vaporize nearly 2 tons of armor, and that a heavy (medium) laser has similar destructive powers, not one could argue that Techmanual is perhaps being a bit hyperbolic with that statement. or perhaps quibble with what exactly it means by vaporize... But Generally that and the fluff indicate that B-tech energy weapons are perhaps a bit overpowered.

Though you forget that a Medium laser requires 2 or 3 tons of heat sinks to operate with out causing a eventual shutdown.
Lasers Generally need less barrel assembly, little to no recoil so no real need for that system, no ammo feed systems or reloading gear, nor do the need to be as robust as theirs no stress of automatic fire on the system.

They do need, aiming systems, power feeds, a lasing system and heat distribution systems among major systems (never mind mounting gear).

So yeah a laser system is going to be lighter than a ballistic weapon.

A Ballistic weapon needs
Gun assembly, aiming systems, mounting systems, recoil gear, loading systems, ammo feed systems (part of the gun not the ammo bin), heat distribution gear and it has to be robust enough to withstand repeated automatic fire. Not to mention durability from taking a hit and keep on going (as their are rules to allow the system to function after taking a critical hit, this also applies to all weapons and IIRC equipment)

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I like having the novels a little separate from the 'science' of the lore. While I deeply respect each of the authors, most of them do often disregard realistic depictions in favor of a more dramatic effect, which is perfectly fine for their purposes, but we can't build consistent physics without consistent rules.

Dose not mean you can completely ignore it, it is canon after all (though so is the game...)

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Unfortunately the rules are hardly consistent when it comes to putting any real scientific comparison between individual weapons even when just using the baseline rules, but the MG really is what breaks the entire universe. Those 2 points of damage either make every other weapon system look hilariously weak, or turn the MG in the most overpowered piece of technology in that universe (aside from Lasers that is).

Most Debates I have been in with B-tech Generally ignored the MG as a base line weapon system, and focused on more real weapons, like Gauss rifles.

Though I will grant you that B-tech is full of contradictions, making it hard to deal with.


Though also keep in mind B-tech is not as hard of a scifi as you seem to think (hint, battlemechs are viable weapons systems), effectively all space craft above a few hundred tons brake the law of thermodynamics, case point 600,000 ton warship accelerating at 1G only uses 39.5 tons of regular hydrogen (that's H2, not the fancy stuff like H3) per day.
B-tech dose seem to have much better metallurgy than we do, case point, they can weave strands of diamond fibers into molten steel to strengthen it with out the diamond being adsorbed by the steel (quite the trick as carbon loves iron...).
Another thing to note B-tech managed to speed up the rotation of Venus, as it has a rotation of 48 hours in B-tech (in real life a day on Venus is longer than it's year which is over 200 days, and not 2 days in B-tech), it is not known how they did this.


In any case It would seem B-tech armor has different protective values for different systems
It seems to do less well on high mass low speed impacts, than it dose with low mass high speed impacts, it also dose not seem to do quite as well with rapid impacts (automatic fire), as it dose with single impacts.

It also handles missiles (largely explosive) and energy weapons differently as well.

[Karl Streiger]

From time to time I'm working on this topic. But while i have try to use several systems, everytime I think I have a solution it slips from my hands.

OK lets see what we have:

TOW - Companion -> Total War Weapon Conversion [While I get working numbers (to compare with TechManual) I'm unable to get the numbers for ordnance.

Obviously, the BT armor value has a "time" component.

So while a trooper HSRM (class F????) deals less BT damage than the standard SRM Launcher with two launch tubes. And still the launcher does less damage than those of the Elemental. (1.14 vs 2/msl)

Not to mention the whopping 0.52 damage of an Autorifle vs 0.16 of the Dragons Bane Support Laser!!!!

Now we need to produce references. One thing is remarkable:
in the ToW Companion a wire-guided missile launcher with ~20kg per missile is mentioned. This fits well with the TOW AT missile. The damage is similar to a Class C- AP Warhead. The same class of a LRM.
Now I might say that a LRM might be able to penetrate 430mm BAR 6 armor. Why BAR6?

The reason is founded in the XTRO1945. using the well documented 88mm L/56 as basic. Known to penetrate 151mm RHA at (90°) using the PzGr 39.
In BT the KwK36 can deal 9dmg when fighting other BAR5 armor. Shooting at better BAR rating I should use the medium rifle. that deals 6 BT damage but only 3 when shooting at a BattleMech, with BAR10. Considering that the a 75mm from the XTRO wouldn't deal any damage where as a 57mm would.

So again the "time component"? A 75mm can't do any harm to a Mech but a AK47 can (0.17)

---

Just realized that their might be another option.... the MachineGuns - dealing 1 dmg at BAR5 but i can convert them into BT damage using the Vintage MachineGun

---

Another attemp I've made was to use other systems: namely CORPS or GURPS.
In both system the construction of a KwK 36 is possible.

TL 9 and a DV 251 using CORPS
TL 6 and a dmg of 6d11(2) or 66 in GURPS

transfering the AV and DR into "metal slates" gives me 83mm CORPS armor or 159 sturcture material
or 160mm TL6 (DR 462 on average) when using GURPS
So I have a BT damage of BAR 5 - in "real", CORPS and GURPS representation.

now BAR6 - TL10/7
I'm confident that I can do the same with BAR6. (aka today)
Take the Silver Bullet of the SB-120mm
670mm at point blank is the goal.

The 22mm L31 arrow weights ~ 4.9kg so roughly 50% of the muzzle energy is used. 5.7MJ
Anyhow in a CORPS setting the DV is 483 ~12 MJ for a 9kg penetrator+sabot ~51% energy for the penetrator but only a 22mm projectile. At 483 the projectile would be able to undo 307mm structure
For GURPS using APFSDS-DU it would be 180 or 6dx30(3) =685mm

GURPS seems to work well with the "real" world.... while CORPS seems to have some problems. (The shaped charge for a 120mm cannon works)

The most simple option seems to use the KWK stats and bring them from GURPS TL6 into TL7 - firing APFSDS-DU 6x22(3) 502mm
But well now things become bad

Maybe at TL8 we could advance the output by using electrothermal - chemical weapon tech, what next?
Real autocannons? Increasing the ROF?

BAR	DMG	TL	GURPS	steel in mm
5	9	6	6d11(2)	160
6		7	6d22(3)	500
7		8	6d33(3)	754
8		9
9		10
10		11

But well now things become bad

Maybe at TL8 we could advance the output by using electrothermal - chemical weapon tech

Edited by Karl Streiger, 20 October 2016 - 07:15 AM.

[Natred]

Pgi needs a guy like Seth to bring the realistic side of battletech universe and real life into one awesome experience.

[Karl Streiger]

OK have done some more work - even was able to get some working CORPS numbers.... so I'm not able to get some kinetic energy - although its not the energy alone - the CORPS system also uses the cross area - so a 22mm dart with 4MJ causes more penetration then a 90mm projectile with 5MJ

Name	BAR	DMG	TL	GURPS	DR	steel in mm	Kinetic Energy	RpM	ShotsTon
KwK 88	5	9	6	6dx11(2)	462	160	3.5 MJ	24	51
KwK 88	6	9	7	6dx22(3)	1386	500	17 MJ	24	115
KwK 88	7	9	8	6dx33(3)	2079	754	27 MJ	24	192
KwK 88	8	9	9	7dx34(3)	2499	906	40 MJ	24	288
KwK 88	9	9	10	6dx46(3)	2898	1051	53 MJ	24	243
KwK 88	10	9	11	8dx23(5)	3220	1168	70 MJ	24	243
HMG 127	5	2	6	13d	46	16		780	7600
HMG 127	6	2	7	22d-1(2)	152	55		1200	11400
HMG 127	7	2	8	3dx11(2)	231	83		1200	11400
HMG 127	8	2	9	3dx11(2)	231	83		1800	28500
HMG 127	9	2	10	3d9(3)	283	102		3000	38000
HMG 127	10	2	11	3dx11(3)	346	125		4020	42800
LMG 762	5	1	6	7d	25	9		960	40100
LMG 762	6	1	7	7d(2)	50	18		1200	40100
LMG 762	7	1	8	10d+1(2)	72	26		1800	100500
LMG 762	8	1	9	17d(2)	119	43		3000	150500
LMG 762	9	1	10	14d-1(3)	147	53		4020	150500
LMG 762	10	1	11	17d(3)	179	65		4980	225500

the KWK deals its damage with a single hit. Firing a 16x469mm dart - accelerated by a electrothermal fused 19kg!!! propellant charge - the arrow impacts with 44 MJ
v0 is almost 7000m/s.....

So this almost AC10 deals its damage with a single hit. Not a burst of shells using plastic cased ammunition the weight is 31kg per shot, with classic casing 58kg


The question that remains is the time factor. When I fire 5 bullets all of them with 14MJ do they the same BT damage as a single 44MJ arrow? I can say for sure that a hypersonic projetile would be as deadly as a explosive shell to unprotected infantry when the shot impacts the ground nearby.

Pushing it to the limits I'm now at 200kg per bullet - and a kinetic energy of 104MJ


Maybe thats the reason its a autocannon firing multiple lesser shots

Edited by Karl Streiger, 21 October 2016 - 06:22 AM.

[Karl Streiger]

So a consensus of my latest "research"
To break a Mech you don't need to penetrate the armor.
It physical not possible that the same 60mm projectile fired by either Landhecht or Victor does in one case ten times the damage.

Quite the opposite the Victors 60mm Pontiac would deliver less energy.
But the difference is the Rate of Fire - where as the Zeus Bolt deliver a single 60mm shell - say ~4-6 MJ the Pontiac delivers 50 -100 3-4 MJ shells in almost the same time frame.

I don't know enough about armor but I bet even when each bullet doesn't have enough force to penetrate a modern mbt front armor - the sheer volume of fire should be enough to make a soft kill.

As said I don't know enough but it seems plausible

[9erRed]

Greetings all,

Just a side note here, about current materials for Armour and how it could rival BattleTech Mech Armour materials.

Recent News:
~~ A new phase of carbon has been discovered, dubbed Q-carbon by its creators at North Carolina State University, and it has a number of incredible new properties. Not only does it appear to be harder than its close carbonaceous cousin, diamond, but it actually has properties the scientists themselves did not think possible. Q-carbon is ferromagnetic, something no other phase of carbon is known to be, and it even glows when exposed to energy. But, exciting as these things are, the most proximate application for Q-carbon is in back-conversion to more natural carbon crystals: With a simple melting process, Q-carbon can be turned to diamond under forgiving conditions.
Depending on just how the Q-carbon is made, it can end up with embedded nano-diamonds, or diamond nano-needles, which are basically just areas of the Q-carbon which did fuse into the perfect diamond lattice structure. But they can also intentionally back-convert the Q-carbon to diamond nanodots, though the exact properties of that diamond aren’t detailed. ~~

Now all this is fascinating, but what application would it have for material like armour?
- Custom build plates or layers with Diamond Q-Carbon built into the structure.
- It's flexible, to a point, lets embed it into material for the Space field or Military Soldier.

Brand new material, strongest known yet, cheap and fast to make, untold possibilities!

Aim True and Run Cool,
9erRed

[Karl Streiger]

Ferromagnetic - lightweight material? - 500K Currie Point....
melting turn them into diamonds.... so when i would equip my Mech with Q-Carbon and some guy fire his laser at me my armor turns into diamonds win win

Carbon is indeed the way to go for Mecharmor -

[9erRed]

Greetings,

Reference that melting process back to a Diamond structure:

- Much higher temperatures and precise alignment required.
- It should hold it's integrity and strength at normal weapons strikes.
- Targeted surfaces would need to be stationary for any effect to start, normally not happening with combat elements.

It's cheap and easy to produce, so we could start seeing this product appear in an industrial use soon. As long as the material is not locked into an "owned" substance. I really think the Space industry could use this material to strengthen space bound elements. We currently have new space suits, tight fitting and flexible, excellent use for lightweight ultra strong layer within these suits. (additionally used for the soldiers body armour suit and vehicle armour.)
- Expect to see armour piercing rounds made with this material. !

Battletech, meet your next armour plating material. That really exists.

Aim True and Run Cool,
9erRed