|
Battletech
Design Philosophy |
|
|
Battletech
Design Philosophy |
Everyone has their own ideas about what makes a good battlemech or combat vehicle under the Battletech Rules. Obviously, so do I. This describes my ideas about unit design, and hopefully helps to explain why many of the designs herein are the way they are.
Contents
|
|
Each individual battlemech is part of a combat force. The organization of a force should be based on the "team" concept. No single combat unit is large enough to carry sufficient weaponry to fulfill all roles in a force well. This means that each combat unit has an individual role to perform within the force. The primary design consideration for that combat unit should be to optimize the unit to fulfill its role. All other considerations, including self defense, are secondary. Thus, units intended for long range support should not carry extensive short range weapons, and units intended for close-in fighting should not waste tonnage on long range weapons. Both of these are common problems with FASA published designs.
Before any battlemech or vehicle is designed or a variant produced, a decision must be made about its function or role. No combat unit is able to do everything well. Therefore, the strengths and weaknesses of a design must be considered before it is put together.
What is the purpose of the unit? What role is it expected to fulfill on the battlefield? How will it work with other units? Is it intended for a support role with long range weapons? Is it a scout, which needs speed and defense more than heavy weaponry? Is it a front line battle unit which needs as much fire power and armor as possible, and is willing to sacrifice speed for this?
Someone who sits up after designing a mech and announces "Boy, is this a great design!" But, who cannot tell you what the function of the mech is, has wasted their time and yours. At the design stage, the role of the unit defines what is needed in the design. Except as a replacement for solitaire, there is no point in designing a "great mech" which has no well defined function.
Obviously, it would be nice to be able to use both of these options on all battlemechs. This is, however, often not possible on any but the smaller mechs, due to the lack of critical space. Whenever there is space for only one of the two, always mount Endo Steel internal structure instead of Ferro-Fiber armor. Endo Steel internal structure will always save more weight than Ferro-Fiber armor, and weight saving is the primary purpose of using either of these options. The following table compares the savings. It assumes the selected mech size carries the maximum possible armor on Inner Sphere designs. For those who wish to maximize the armor on a mech, note that the weight savings by Endo Steel is sufficient to cover all the extra armor which would have been gained by the use of Ferro-Fiber armor, with spare to allow additional equipment to be carried.
| Mech Tonnage |
Internal Structure | Armor | |||||
|---|---|---|---|---|---|---|---|
| Standard | Endo Steel | Savings | Pips | Standard | Ferro-Fiber | Savings | |
| 20 | 2.0 | 1.0 | 1.0 | 69 | 4.5 | 4.0 | 0.5 |
| 50 | 5.0 | 2.5 | 2.5 | 169 | 11.0 | 9.5 | 1.5 |
| 100 | 10.0 | 5.0 | 5.0 | 307 | 19.5 | 17.5 | 2.0 |
Controlling the production and dissipation of heat by a battlemech is the key to optimizing its performance on the battlefield. The common designs do not have sufficient heat sinks to allow all of the heat generated by a mech's movement and weapons to be eliminated as it is produced. The result is that the mech must, at some point, reduce the number of weapons firing and/or reduce its movement. Obviously, the times the mech most needs to shot and move freely are the times this problem will typically arise.
A typical example demonstrates the advantage of extra heat sinks. The classic ARC-2R Archer, if it does not move, and fires only its two LRM 20 mounts, will overheat by 2 per turn. Assuming the unit does not wish to suffer any negative modifiers (5+ heat), it must periodically cease firing one of the LRM 20s to allow itself to cool down. The cycle is two turns firing both LRM 20s, followed by one turn firing only one LRM 20. It thus has a total potential damage of 100 points (five firings of an LRM 20) in three turns, or an average of 33.3 points per turn. If it carried sufficient heat sinks to remove all of its heat, it could fire both LRM 20s continuously, generating 40 points per turn of potential damage, or a 20% increase in its maximum potential damage.
The simplest way to increase the amount of heat removed per turn is to use Double Heat Sinks. However, as the preceding example suggested, it is also possible to decrease the number of weapons, increase the number of heat sinks, and thereby increase the total fire power. Following the principle expounded in the General Concept above, the example Archer can sacrifice two of its Medium Lasers to mount two additional Single Heat Sinks, and so allow it to stand still and use both LRM 20s continuously (note that this is only a partial fix to its problems). Since it is primarily a long range support mech, its functionality in a combat force is not significantly reduced by the loss of medium range weapons, especially since its long range capability is increased notably.
When determining the heating of a battlemech, add the heat for the worst case of movement to the heat generated in the worst case by all weaponry and equipment, and subtract the amount of heat the heat sinks may dissipate. For movement this will be either the 2 points of heat for running or the jump distance of the mech (minimum 3 points of heat). Unlike with previous versions of the rules, under the new Multiple Targets Modifier rule (Battletech Master Rules, page 30), it is now possible for a mech to fire all of its weapons, including rear facing weapons, in one turn. Therefore, all weapons must be counted for purposes of totaling heat generated in a turn.
So what is acceptable? The following table summarizes the status of designs based on the excess heat per turn, assuming the mech has taken no damage to its heat sinks or engine.
| Heat | Description | Status | Comments |
|---|---|---|---|
| -4 or less | Cold | Too Good | This is acceptable only in a smaller mech which uses an XL engine. It may expect to suffer an engine hit, and the excess heat dissipation is able to handle the problem. Unless the mech already has the minimum number of Heat sinks (10), consider a redesign to remove heat sinks and add weapons. |
| -3 to +2 | Cool | Good | Any positive heat should come only from secondary weapons which are not likely to be used except in special cases or from jump jets (which don't have to be used). |
| +3 to +5 | Warm | Acceptable | Acceptable if the heat above zero is generated by weapons which are not normally used, ex. short range weapons carried by a mech designed as a long range support unit. |
| +6 to +8 | Hot | Unacceptable | The mech will suffer serious negative modifiers immediately upon firing all its weapons. The next turn it will have to significantly reduce its fire or movement. Replace weapons with heat sinks. |
| +9 or more | Stupid | Stupid | What's the point of a mech like this? A major portion of its weapons will either never be fired or will fire only intermittently. Toss the design in the trash. |
A major debate involves whether weapons and equipment should be mounted in the torsos or the arms of battlemechs. Mounting weapons in the arms provides greater flexibility. Such weapons have a greater arc of fire, and, if the Lower Arm and Hand are removed, are able to fire behind the mech. The problems for arm mounting are that arms have less armor and internal structure than torsos, plus, if the associated torso is destroyed, the arm becomes useless also. Torso mounted weapons are usually under heavier armor, and provide protection against critical hits on engines (in the Center Torso or for XL engines in the side torsos). However, such weapons may only fire in the direction the torso is facing.
When mounting weapons or other equipment, to minimize the effects of critical hits, it is generally better to cluster them in one location, than to spread them out. For example, given the need to place six critical slots worth of weapons in the arms, they could be placed three in each arm, or all six in one arm. The chance of a critical hit on an arm striking a weapon when the weapons are distributed between the arms is 43%. The chance of a critical hit on an arm striking a weapon when the weapons are clustered in one arm is 30%. When this procedure is used for side torso mounted weapons the percentages become even more dramatic. With six weapon criticals divided evenly between the Left Torso and the Right Torso, and no other critical slots present in either torso, the chance of a side torso hit striking a weapon slot is 100%. With the weapons all in one side torso, the chance of a critical hit on a side torso weapon slot is only 50%.
Given the percentages for clustering torso mounted weapons, the only time weapons should not be centralized is if the unit carries an XL engine. In this case, the torso mounted weapons become a form of protection for the critical slots of the XL engine. The weapons should be placed to put as many critical slots in each torso as possible. If possible, the two open slots in the center torso should also be filled, to provide a small chance that a critical hit in that section will not damage the engine or the gyro.
The various Weapons And Equipment Tables give a clear listing of the weight (Tons) and Critical slots required for each weapon. This is, for design purposes, somewhat inaccurate. The Effective Weapon Weight for any weapon is the total of the weapon's actual weight plus the weight of any additional heat sinks needed to eliminate the weapon's heat. The Effective Weapon Criticals applies in the same manner for the critical slots for a weapon. The Effective Weapon data should be used when designing any mech on which the total heat generated exceeds the cooling capability of the ten heat sinks in the engine.
To determine the Effective Weapon Tonnage, add the Tons for the weapon to its Heat divided by the type of heat sink used in the design. For example, on a mech with Double Heat Sinks, an ER Large Laser would have an Effective Weapon Tonnage of 11 tons (5 tons for the weapon plus 12 heat divided by 2 for the Double Heat Sinks).
To determine the Effective Weapon Criticals for a weapon, add the Criticals for the weapon to the Heat divided by the type of heat sink used in the design. For example, on a mech with Double Heat Sinks, an ER Large Laser would have an Effective Weapon Criticals of 8 (2 for the weapon plus 12 heat divided by 2 for the Double Heat Sinks).
Autocannons are the weapons which demonstrate most clearly that FASA had no concept of how weapons work. This issue is covered separately in the Comments.
The only autocannon which is normally worth considering for general purpose use is the LB 10-X Autocannon. This is the only autocannon which has sufficient range and marginally adequate damage capability. Its primary purpose is to take the place of a Gauss Rifle when a unit is not able to carry a Gauss Rifle.
The Autocannon/2, Autocannon/5, LB 2-X Autocannon, LB 5-X Autocannon, Ultra Autocannon/2, and Ultra Autocannon/5 all do too little damage for their tonnage and critical space requirements. Arguments for the greater ranges of these weapons only support their use in special cases, especially since all ranges are relatively limited compared to the speed of most mechs and vehicles. The Autocannon/10 is simply inferior to the LB 10-X Autocannon. The Ultra Autocannon/10 is just enough larger and hotter than the LB 10-X Autocannon to cause the LB 10-X to be preferred.
The Autocannon/20, LB 20-X Autocannon, and Ultra Autocannon/20 are all eclipsed by the Gauss Rifle. Although the Gauss Rifle does only 15 points of damage compared to these autocannons' 20 points, the Gauss Rifle is able to shoot farther and with greater chances of hitting. This allowes it to apply its damage for notably longer periods. This greater range also means the unit carrying the Gauss Rifle instead of an Autocannon 20 variant is not subject to the fire of smaller weapons (Medium Lasers, SRMs, etc.) over much of its range.
Therefore, in almost all cases where one might consider an autocannon, a Gauss Rifle or Light Gauss Rifle would probably be a better choice. If these weapons cannot be fitted, then the LB 10-X Autocannon is a tolerable substitute.
The only case where a large autocannon has a use, is on mechs or vehicles which are both large and fast, and which are intended for very close combat. Then, and only then, will such large autocannons be the preferred selection over the Gauss Rifle. In such a case, the obvious selection should be the LB 20-X Autocannon.
Anti-Missile Systems (AMS), whether cannon or laser, are essentially junk. The Laser Anti-Missile System has the potential to generate excessive quantities of heat. The cannon version uses ammunition as if it had an unlimited magazine, and is rarely able to get more than three defensive shots per ton of ammunition. And, most importantly, it is relatively easy to "trick" an AMS into firing at the least dangerous missile attack, so as to leave the more deadly attacks free from defensive fire. A design is almost always better to carry extra offensive weapons or armor rather than mounting any form of AMS.
On battlemechs, Machine Guns are not only effectively useless, but are a passive danger to the mech itself. The primary purpose of Machine Guns is to provide an excuse for mounting Machine Gun Ammunition, which seems to be a magnet for critical hits, which, of course, cause the ammunition to explode and destroy the mech. It is almost impossible for any well designed mech to ever use even one-half ton of Machine Gun Ammunition in a battle (and if you are able to do this, you are doing something very, very wrong). Although weighing more, a Small Pulse Laser is, on average, as good as a Machine Gun for anti-infantry work, and does not include the danger of an ammunition explosion.
If someone is forced to use a mech which is equipped with Machine Guns, they should specify that most of the shots are offloaded prior to the battle. A mech needs no more than about ten shots per Machine Gun for any normal battle. This will, at least reduce the danger from the ammunition.
Finally, none of this applies to vehicles. Vehicles store their ammunition in their Bodies. If the Body is hit, the vehicle is already knocked out, so an ammunition explosion is only going to reduce the vehicle's scrap value.
NARC Beacon Launchers and Target Acquisition Gear (TAG) should almost never be mounted on the same combat unit as the launchers for the missiles they will direct. The ARC-5W Archer is a classic example of a mech designed with this error. A unit equipped with LRMs would generally prefer to remain at longer ranges. The maximum range for the NARC Beacon Launcher (9 hexes) is only somewhat greater than the minimum range of the LRMs (6 hexes). Clearly, such a unit should rarely be in a position to fire its NARC Beacon Launcher, and will not like to be in that position if it does. Obviously, the NARC Beacon Launcher should be on a different unit which is intended to fight at a range at which the NARC Beacon Launcher is effective.
The only possible exception to this prohibition is the mounting of TAG on a vehicle, but not a battlemech, which also carries the Arrow IV Missile Artillery System. In such a vehicle there will be a separate crew member for each system, thus allowing the Arrow IV to be fired in the same turn the TAG is used.
CASE* is an essential component of any battlemech which carries any explosive equipment (ammunition or a Gauss Rifle). To minimize the damage to a mech with ammunition (excluding Gauss Rifle or Light Gauss Rifle ammunition) all ammunition should be stored in a side torso, and that torso should have CASE applied. This insures that a hit to the ammunition will not destroy the mech. If a Gauss Rifle is mounted in an arm, then the associated side torso should have CASE applied, even if that side torso does not contain any explosive ammunition.
CASE is never needed in the Center Torso. Any damage for which CASE would be useful in this section would destroy the engine, and so render the mech inoperable. Also, obviously, under no circumstances should ammunition be stored in the Center Torso (or the Head, but that should not require mentioning).
Finally, CASE is of only slightly limited usefulness on a mech with an XL engine. As with the Center Torso, any CASE abated damage to a side torso would still destroy the engine. The only purpose of CASE in such a situation is to protect the pilot and maximize the amount of salvageable equipment.
* This discussion applies primarily to Inner Sphere designs, as Clan mechs have CASE automatically as needed. On Clan mechs ammunition should be stored in the arms, as an explosion will be vented there and so protect the associated side torso.
The XL (Extra Light) type of engine was once seen as the best method for reducing the non-weapon weight of a battlemech. It is, however, a mixed blessing. Doubling the number of critical hit locations used by the engine, and putting these locations in the side torsos, makes the mech much more susceptible to engine damage, with its near crippling consequences.
Given this increased danger of engine damage from critical hits, the use of XL engines in light or smaller medium battlemechs is highly inadvisable, even though such mechs are the very types which most need the extra tonnage for other equipment. Such units do not have sufficient armor to protect any location, and generally do not carry enough equipment in their torsos to reduce the chance of a hit to the engine to acceptable levels. Such levels would be defined as having at least nine of the twelve critical slots in each torso filled with something which can take a critical hit.
Therefore, if an XL engine is to be mounted in any battlemech, the heavy and assault mechs appear to be the best candidates. When using an XL engine, as many other critical slots as possible in the side torsos should be filled.
Finally, the Maximum Tech book describes additional engines, including the XXL (Extralight XL, page 65). This engine is too stupid to warrant much discussion here, except to note that it should never, never even be considered, much less used.
Despite all the Technical Readouts, all of the published designs, and the numerous models, there actually are only a limited number of fundamentally different battlemechs. At the very simplest, there exist only seventeen unique battlemechs. These are one for each of the tonnages from 20 tons through 100 tons, inclusive. Everything else about a mech design is simply a matter of detail.
Some may answer this by noting that even today different combat equipment with the same basic tonnage looks different, and so mechs of the same tonnage could also be different. This is not an accurate comparison. Modern tank designs, for example, are unique because their components are unique. The suspension system from a U.S. M1 tank will not work on a British Challenger tank. However, the same is not true for battlemechs. All battlemechs of a given tonnage have interchangeable parts. If a 35 ton Firestarter has a Left Arm Upper Actuator destroyed, it may replace that actuator with a similar component from any other 35 ton mech, including a Clan mech. Further, one could not remove the driver's compartment and equipment from any other tank in the world and put it into an M1 tank. But, all standard cockpits on all battlemechs are the same.
This situation merely demonstrates that the written explanations and background materials regarding the design, functioning, and looks of battlemechs are totally inconsistent with the rules of the game (or vise versa, depending on your point of view). Undoubtedly the most important factor driving the so called "different" battlemech designs is the desire to sell more models, not the logic of the game system.
What this means for the design of battlemechs is that all designs of a given tonnage are effectively interchangeable. There really is no difference between, for example, a 30 ton Spider, Javelin, or Urbanmech. Any design created for an Urbanmech can be created on a Spider. All the differences are simply a matter of one's imagination.
|
|
|
Updated 20 June 1999. |