So. I realize Protos are sort of the red-headed stepchild of Battletech, and this subforum isn't frequented much. But what the heck, I came up with these rules for IS Protos on a lark while the forums were down. Lemme know what you think, suggestions are welcome and I'll edit this if some good ideas show up in this thread.
Unofficial IS Protomech Construction Rules
As of 3090, the Inner Sphere has gained the ability to manufacture their own take on Clan Protomech technology. However, with the prevailing views dead-set against the invasive Direct Neural Interface technology that gives Clan Protomechs many of their advantages, IS factions have had to resort to a few workarounds. Conversely, the IS has a number of technologies available to it that the Clans do not use, or have not considered.
1) ProtoMech Type and Weight
As with Clan ProtoMechs, IS Protos can be anywhere from 2 to 15 tons, in full-ton increments.
IS Protomechs of all weights can be constructed using either the bipedal or quadrupedal (quad) chassis types. However, Glider ProtoMechs cannot be constructed with Inner Sphere technology under these rules.
2) Internal Structure
The Inner Sphere has more variety available to it as far as internal structure goes. While ProtoMechs are still far too small for bulky Endo-Steel construction to be viable, IS ProtoMech designs may make use of the following internal structure types:
Type Weight (% of max) Other effects
Standard 10% None
Industrial 20% None
Composite 5% Internal damage is doubled
Reinforced 20% Internal damage is halved (rd up); -1
modifier vs. crits
Primitive 10% +1 modifier vs. crits.
3) Engine and Motive Systems
As with Clan ProtoMechs, an IS ProtoMech's engine size is calculated by multiplying the Proto's max weight (in tons) by its desired run speed (in hexes). If the result is above 40, round the result up to the nearest multiple of 5. If it's below 40, multiply the result by 25kg to get the weight of the engine.
If the ProtoMech is a Quad, reduce the run speed by 2 for the above calculation.
The following engine types may be used on Inner Sphere ProtoMechs: Standard, Trimmed, Primitive, Compact, Fission, ICE, Fuel Cell. Don't use the weights from the Master Engine Table; instead, multiply the Standard weight by the following values:
Type Multiplier
Compact* 1.5
Fission 1.75 (Minimum 5T)
ICE 2
Fuel Cell 1.2
Trimmed (AU only)** 0.875
Primitive As Standard, but multiply
Engine Rating by 1.2 for
no benefit
*ProtoMechs with a Compact engine require four critical hits to the torso to disable, rather than only three.
**ProtoMechs with a Primitive engine function identically to those using a Standard engine.
***ProtoMechs with a Trimmed engine are identical in gameplay to those with a Standard engine, but the maximum equipment in the torso is now only a total of 500kg, or 1,000kg if the Proto is 10 tons or heavier. The Trimmed Engine is only available in the Vaults AU timeline.
ProtoMech engines do not have any integral heat sinks.
Jump Jets and UMUs are available for IS ProtoMechs, following the same rules as the Clan equipment of the same name.
IS ProtoMechs cannot take advantage of ProtoMech Myomer Boosters or Extended Jump Jets, having not yet miniaturized MASC or IJJs to the level needed. Similarly, Triple Strength Myomer is not available for ProtoMechs.
4) Gyro
Clan ProtoMechs get around the need for a Gyro by linking the ProtoMech's myomers and stabilization to the pilot's brain. Since the Jihad, however, the stigma in the Inner Sphere against Direct Neural Interface has been too great to pursue such research in earnest.
Therefore, IS Protos require a Gyro.
IS ProtoMechs from 2 to 9 tons use the same rules for determining Gyro weight as for BattleMechs, but divide the resulting weight of the Gyro in half. However, if an IS ProtoMech is 9 tons or less, has an Engine with a Rating of 50 or less, and does not mount Jump Jets, it only requires a quarter-ton (250kg) Gyro.
IS Ultra ProtoMechs use the same Gyro weight scale as BattleMechs.
ProtoMechs may make use of Compact Gyro technology. Heavy-Duty, Extra-Light, and Light Gyros, on the other hand, are far too bulky.
5) Control Systems
As the IS's ProtoMech control systems were kludged together from BattleMech and Battle Armor technology, they are significantly heavier and more unwieldy than the Clan systems.
On IS Protos from 2 to 5 tons, these systems weigh 500kg.
On IS Protos from 6 to 9 tons, these systems weigh 750kg.
On IS Protos 10 tons and up, control systems weigh 1000kg (1T).
Primitive control systems increase this number by a further 250kg.
6) Heat Sinks
The IS has not quite been able to copy the compact, lightweight heat sinks of the Clan ProtoMechs. Heat sinks on IS Protos weigh 300kg each, but otherwise follow the same rules as on Clan Protos.
7) Armor
Armor for IS Protos is 16.67 points per ton (1 point per 60kg) and can be bought per-point. Primitive Armor is also available at 11.11 points per ton (1 point per 90 kg), but is only produced for Protos in the Vaults AU timeline. Other armor types are not available for IS ProtoMechs.
Max armor follows the same limitations as Clan Protos.
8) Weapons, ammo, etc
All weapons must have adequate heat sinks to keep the Proto running heat-neutral. Additionally, if the ProtoMech is powered by a non-nuclear engine, it must mount a Power Amplifier, with its weight equal to 1/10 the combined weight of all energy weapons (excepting "energy" weapons that use ammo, like Chemical Lasers and Vehicle Flamers).
Apart from that, and the equipment tonnage limitations common to all Protos, IS ProtoMechs can mount whatever weapons and equipment the player so desires, including ProtoMech Melee weapons.
Weapon reference table:
* MG, Light MG (5kg/shot)
* Heavy MG (10kg/shot)
* Anti-Missile System (40kg/shot)
* the Light Rifle (50kg/shot)
* AC-2, LBX-2, Ultra AC-2, and Light AC-2 (20kg/shot)
* AC-5, LBX-5, and Light AC-5 (50kg/shot)
* the Magshot (20kg/shot)
* the Fluid Gun (50kg/shot)
* Mortar/1 (40kg/shot), Mortar/2 (80kg/shot), Mortar/4 (160kg/shot)
Most missile weapons are bought per-tube, just as with Clan Protos.
* SRMs (0.5T per tube) (10kg/missile)
* Streak SRMs (0.75T per tube) (10kg/missile)
* MRMs (0.3T per tube) (4kg/missile)
* LRMs (0.4T per tube) (25kg/3 missiles)
* EnLRMs (0.6T per tube) (25kg/3 missiles)
* ExLRMs (0.8T per tube) (25kg/2 missiles)
* RLs (0.05T per tube)
* LSMs (0.25T per tube) (4kg/missile) (Vaults AU only)
* MMLs are not usable by ProtoMechs.
* HAMs (Vaults AU only) are not usable by ProtoMechs.
* VRMs (1T per tube) (25kg/2 missiles) (Vaults AU only)
Also available are:
* TBolt-5 (80kg/missile)
* NARC (160kg/missile)
* BattleMech Taser (200kg/shot)
Gameplay rules for IS ProtoMechs
IS ProtoMechs follow the same gameplay rules as Clan Protomechs, with the following exceptions:
- IS ProtoMechs operate in platoons of 4, not 5. The (as yet hypothetical) exceptions are Comstar, whose Level 1s would consist of *six* Protos, and the Marian Hegemony, whose units operate in groups of five.
- On the first or second critical hit of an IS ProtoMech's torso, its gyro may be hit on a roll of 5, when rolling to see if a torso-mounted weapon has been taken out.** One hit is sufficient to destroy the gyro, reducing the ProtoMech's top speed to 1 MP and disabling its jump jets.
** Exception: If the ProtoMech mounts a Compact Gyro, roll 1d6 a second time. On a 1, 2, or 3, ignore the critical hit.