950 replies to this topic

[Melcyna]

SakuranoSenshi, on 13 August 2012 - 09:47 PM, said:

I agree that the difference between railguns and coilguns is largely semantics. I know why they are different but I also know that they use exactly the same principles to generate their force, when you get down to it. Technically, both are a form of motor.

Indeed both are more or less using the same base principle,

but the difference in their propulsion force application is significant enough that they both face different challenge.

For example, the fact that a Railgun projectile forms part of the circuit that channels the current through means 2 things that have been among the most significant challenge with it's design:
1. part of the armature is always in contact with the rail, either directly or through some form of conducting lubricant... normally they don't contact directly since you need some form of lubricant there to prevent excessive friction (unless if the armature itself is made of the lubricant material on the contact surface), either way you can't avoid friction between the armature and the rail since there must be a current pathway through them.

2. the massive current that is flashed through the circuit itself generates substantial heat on the armature unless steps are taken to prevent it.

Just the 2 above arises from the simple fact that the current had to pass through the armature, without proper prevention... the armature will simply vaporizes with high current railgun, with our best design we managed to minimize it but rail erosion is still one of the biggest problem next to the power with railgun design.

Coil gun on the other hand have different set of challenge and problems, the problems above with railgun in general are not their concern...

[Theodor Kling]

SakuranoSenshi, on 13 August 2012 - 10:47 PM, said:

What makes you think they should?

The only real thing with the LASERs, or rather the most obvious thing with them, is that you can't actually see a LASER beam unless there is scatter (say from dust) or you're on the receiving end. However, to do damage with one you probably want non-visible frequencies anyway.

The lasers frequency is of no importance if the energy densities ae high enough, you get a vivisble beam by total ionization of the air the beam passes though.
Although it is not bright enough to go blind from it, the spectrum should be quite broad, so you might get a sunburn, and also an unhealthy dose of x-rays.

Edited by Theodor Kling, 14 August 2012 - 03:56 AM.

[SakuranoSenshi]

The frequency matters because higher frequencies are more energetic over the same time period. If you're totally ionizing the air (unlikely now but possible with weaponized LASER, I'll warrant) you're wasting power on that.

[SakuranoSenshi]

Melcyna, on 14 August 2012 - 12:41 AM, said:

Indeed both are more or less using the same base principle,

but the difference in their propulsion force application is significant enough that they both face different challenge.

For example, the fact that a Railgun projectile forms part of the circuit that channels the current through means 2 things that have been among the most significant challenge with it's design:
1. part of the armature is always in contact with the rail, either directly or through some form of conducting lubricant... normally they don't contact directly since you need some form of lubricant there to prevent excessive friction (unless if the armature itself is made of the lubricant material on the contact surface), either way you can't avoid friction between the armature and the rail since there must be a current pathway through them.

2. the massive current that is flashed through the circuit itself generates substantial heat on the armature unless steps are taken to prevent it.

Just the 2 above arises from the simple fact that the current had to pass through the armature, without proper prevention... the armature will simply vaporizes with high current railgun, with our best design we managed to minimize it but rail erosion is still one of the biggest problem next to the power with railgun design.

Coil gun on the other hand have different set of challenge and problems, the problems above with railgun in general are not their concern...

I agreed they're different but like someone else posted, I see that more akin to difference in various internal combustion engines than say, between a rocket motor and a turboprop engine. As for the friction thing, plasma has been used to make the links with success but I expect serious wear on the rails is still an issue.

[Brenden]

Are Autocannons Machine Guns, Burst Fire or Single Shot?
Also, is 45mm considered the round for an AC5 or AC2?
I wonder why there aren't any AC25s or higher...

[Theodor Kling]

Brenden, on 14 August 2012 - 09:39 AM, said:

Are Autocannons Machine Guns, Burst Fire or Single Shot?
Also, is 45mm considered the round for an AC5 or AC2?
I wonder why there aren't any AC25s or higher...

Most ACs are Burst Fire, but there are a few single shot ones. Depends on the actualy model. AC2/5/10/20 is just a classification, no actual weapon.
In regard to AC25 or higher: With AC20s beeing so short ranged already ( probably due to recoil issues for most models.. an ongoing discussion ) AC30 or such would be basicly a point blank weapon... so a melee weapon could do the job , without risking ammo explosions.

SakuranoSenshi, on 14 August 2012 - 05:09 AM, said:

The frequency matters because higher frequencies are more energetic over the same time period. If you're totally ionizing the air (unlikely now but possible with weaponized LASER, I'll warrant) you're wasting power on that.

There are already real world visible lasers. Unfortunately I can´t find the article about it right now ( will keep on searching..I should boomark such stuff).
Your argument about wavelengths is a good point though. But I think other factors come in too. There coudl be enenieering problems with the small wavelength weaponized lasers, so that using more neregy on a longer wavelength might be a good idea.
I am not that learned in laser physics, but I could imagine that reducing energy densities inside the weapon at the cost of more total energy used might help with material stress.

EDIT: Strange.. I posted my text twice within the same post

Edited by Theodor Kling, 14 August 2012 - 10:15 AM.

[Brenden]

Theodor Kling, on 14 August 2012 - 10:14 AM, said:

Most ACs are Burst Fire, but there are a few single shot ones. Depends on the actualy model. AC2/5/10/20 is just a classification, no actual weapon.
In regard to AC25 or higher: With AC20s beeing so short ranged already ( probably due to recoil issues for most models.. an ongoing discussion ) AC30 or such would be basicly a point blank weapon... so a melee weapon could do the job , without risking ammo explosions.

There are already real world visible lasers. Unfortunately I can´t find the article about it right now ( will keep on searching..I should boomark such stuff).
Your argument about wavelengths is a good point though. But I think other factors come in too. There coudl be enenieering problems with the small wavelength weaponized lasers, so that using more neregy on a longer wavelength might be a good idea.
I am not that learned in laser physics, but I could imagine that reducing energy densities inside the weapon at the cost of more total energy used might help with material stress.

EDIT: Strange.. I posted my text twice within the same post

Mmm... Alright. But heres what I want to know also.. If the round is bigger, shouldn't it go farther?

[Theodor Kling]

Brenden, on 14 August 2012 - 10:59 AM, said:

Mmm... Alright. But heres what I want to know also.. If the round is bigger, shouldn't it go farther?

Not neccesarily. Most pistols and revolvers fire way bigger rounds( diameter wise) then rifles. But the rifles got the longer range. Sure , they use more propellant mostly, but barrel length is also important. ( there are a few rifles and pistols sharing ammo that show that very clearly)
And while a lot of lighter AC´s are shown to have long barels ( think about that barrel as long as the mech on top of a Marauder, or the "arms" of a Rifleman) heavier ACs are usually shown with shorter barrels ( just look at the Hunchback... that AC casing is extremely short compared to barrel diameter)

[Elessar]

Theodor Kling, on 14 August 2012 - 01:46 PM, said:

Not neccesarily. Most pistols and revolvers fire way bigger rounds( diameter wise) then rifles. But the rifles got the longer range. Sure , they use more propellant mostly, but barrel length is also important. ( there are a few rifles and pistols sharing ammo that show that very clearly)
And while a lot of lighter AC´s are shown to have long barels ( think about that barrel as long as the mech on top of a Marauder, or the "arms" of a Rifleman) heavier ACs are usually shown with shorter barrels ( just look at the Hunchback... that AC casing is extremely short compared to barrel diameter)

Yep, barrel length increases accruacy ... which is why the Leopard 2 from version 2A6 upwards replaced its Rheinmetall 120 mm L40 (the same gun that is (under another designation) in the M1A2 Abrams with a Rheinmetall 120mm L55 (same diameter, but longer barrel)

[SakuranoSenshi]

Technically, no rifle shares a calibre with a pistol, that's what a carbine is. :-P

Otherwise, yup. It's not as simple as one factor or another, ballistics is quite complicated in reality. Longer barrel, to a point, means higher speed out the muzzle (too long and it actually drops) it also implies a longer sight radius on small arms (unless the maker is incompetent or something!). Larger diameter is heavier projectile, as a rule, but that tends to be most useful for short range firearms, rifles are intended to engage at longer ranges which means higher muzzle speeds so as to minimize the effect of drop, time to target, etc.

Of course, larger vs smaller is relative... we're talking giant walking robots so we can assume some pretty big bullets. :-)

[Melcyna]

Which ironically made for an odd situation,

If the large bore AC are using short barrel in relative to their mass and bore, then the projectile's muzzle velocity can't be that fast since one need sufficient barrel length for a given propellant mass to actually accelerate the projectile up to the speed which more or less imply that they are using low velocity gun for the large bore AC.

That technically helps the argument as to why they are so inaccurate or have incredibly short range (not really, even some of our slowest low velocity gun have effective range far in excess of that), but that begs the question of how they do the damage they did relative to lighter AC.

If it's through kinetic energy then that would naturally make little sense, if it's through chemical charge (ie: explosive payload of a sort) then logically a rocket would be even more lethal since rockets have very large payload per weight ratio at the expense of speed... but they are already using a gun with such low velocity that it can't be effective beyond mere few hundreds of meters anyway.

SakuranoSenshi, on 14 August 2012 - 05:13 AM, said:

I agreed they're different but like someone else posted, I see that more akin to difference in various internal combustion engines than say, between a rocket motor and a turboprop engine. As for the friction thing, plasma has been used to make the links with success but I expect serious wear on the rails is still an issue.

It's likely that it'll be among the main issue for the foreseeable future on railgun design until some significant leap on tech is achieved that will change the fundamental design on it, meanwhile coilgun suffer virtually no such problem (but have others of their own that railgun don't share either).

But to be more specific the main problem with generalizing the two together is that coil gun and railgun are not interchangeable in their intended function either for some scenarios... for example propulsion based mass driver. The engine analogy suggests that one can replace either a coil gun or a railgun with the other to perform the same function (ie: lobbing mass out). In practical term however the two design have such different set of strength and weakness (railgun needing the armature to pass the current through effectively made them impractical for propulsion for example) that this is not really the case, and it is one of the reason why the research for coil gun and railgun goes the separate ways they are.

Edited by Melcyna, 14 August 2012 - 03:55 PM.

[IcePho3nix]

- Center of gravity and effective weight distribution have little to no actual bearing on battlemech construction (i.e. the King Crab, with stick arms carrying AC20s and a torso that sits far past its feet)

[Grey Weasel]

Tussock, on 31 July 2012 - 11:33 PM, said:

Channeling the energy to power a 100kg+ gauss rifle slug up to mach 6 generates no heat!

A slug the size of a VW Bug only weighs 100kg!

[Grey Weasel]

Lunareclipse, on 03 August 2012 - 07:46 PM, said:

I'm not sure if I remember this correctly, but on the orbital bombardment thing, I think there was some treaty signed by all the member states of the Star League banning both orbital bombardment and the use of WMDs, and the legacy of this treaty is that all wars in the Inner Sphere are fought by conventional forces. There are times that it's been broken, but it seems the exception rather than the rule.

I'm going to try and find it on sarna.

Edit: Okay, I can't find anything specific, but there are numerous traties and accords that are just stubs on that wiki, and any one of them could be this... or I might be entirely wrong.

The Ares Convention -- http://www.sarna.net...res_Conventions

[Grey Weasel]

Quietly Crazy, on 03 August 2012 - 11:25 PM, said:

And before anyone gets on me about the beam spam comment: I know it is more about creating something that can operate without having to worry about ammunition...it just seems silly when looking at the game from a real world point of view. But if anyone thinks it isn't awesome? They're wrong.

50 MW krypton laser at Wright-Patterson AFB. 'Nough said.

[Razor Kotovsky]

IcePho3nix, on 14 August 2012 - 04:24 PM, said:

- Center of gravity and effective weight distribution have little to no actual bearing on battlemech construction (i.e. the King Crab, with stick arms carrying AC20s and a torso that sits far past its feet)

This is getting fixed (though Jenner is still retarded).

Edited by Razor Kotovsky, 14 August 2012 - 05:24 PM.

[Brenden]

Oh great, I made another debate about the Autocannon. ~w~ I feel sad now...
... Though, I wonder what the mm is for an AC/10...

[Theodor Kling]

Brenden, on 14 August 2012 - 05:33 PM, said:

Oh great, I made another debate about the Autocannon. ~w~ I feel sad now...
... Though, I wonder what the mm is for an AC/10...

You realy can´t tell. The AC10 on a Centurion looks like a larger calibre. But the AC10 on a Dragon looks a bit smaler in barrel diameter ( but has a much thicker casing around the barrel, suggesting more recoil compensation equipment, so it probably fires longer bursts). Depends onf manufactuer. That's for the old drawings. The MWO concept art shows their arms to be exactley the same.

And to the center of mass issue: yeah.... some mechs realy got problems there. Again the Cenuion: with that AC10 on a medium mech, fired from an arm... he probably should spin around when fireing it.
But at least they thought conservation of momentum with the Heavy Gauss.

Edited by Theodor Kling, 14 August 2012 - 10:11 PM.

[JackTD]

I allways hated the range issue the most about BT.

Missiles with ranges below 1km and Lasers with even less .

A friend of mine and me we stumbled accross the idea to increase the hex size form 30m² to 150m². This gave us much more realistic ranges for the weapons.

In order to counter the range/speed issue (a Locust in this system would have a speed of thundering 648km/h) we also increased the time frame from 10 seconds per combat round to 1 minute per combat round (now the Locust would limp at 108km/h).

Though the BT is still flawed in many respects, this ratio alteration made it much more appealing to me.

On big flaw is the entire artillery system of BT - it even allows to adjust aiming for rounds in mid air .

Edited by JackTD, 15 August 2012 - 06:50 AM.

[Elessar]

JackTD, on 15 August 2012 - 02:44 AM, said:

...

On big flaw is the entire artillery system of BT - it even allows to adjust aiming for rounds in mid air .

It does?
Never played with Artillery much, but IIRC (at least with normal Ari, like Long Tom or Thumper) you would have to announce a hex on which the shell should land several turns beforehand and then the shell would land there or in vicinity, depending on the presence of advanced observers, several turns later (with the time of flight being dependant on the distance of the artillery to the location of battle, measured in battletech maps).
Cannot remember any rules that allowed for course correction mid flight