Super-science Options for Modular Mecha

 Yet more options for David Pulver’s Modular Mecha (Pyramid volume 3 issue 51).

Reactionless Thrusters (TL 10^, 1 DP): Allow flight as for jump jets, but do not require fuel. Instead, each second of use consumed energy equivalent to one shot from a beam weapon.

Force Screen (TL 10^, 1 DP, can be taken twice): Gives ablative DR equal to the lower DR for the mecha’s base model (e.g. DR 600 for a standard light mecha). These early force screens are less efficient than the TL 11^ ones in Ultra-Tech: they consume energy equal to one beam weapon shot every second they are active and the mecha counts as moving if they are shut down and regenerating. Alternatively, they may be velocity screens which consume energy equal to one beam weapon shot only when activated by an incoming attack (this is sufficient to remain active for one second).

Transformation (TL 10^, 1 DP, can be taken twice): The mecha can change shape into a different style of vehicle, gaining the Alternate Form advantage. A mecha’s arms and legs may not be used while transformed.

Boat: Water Move 4/32.

Plane (requires Jump Jets): Air Move becomes 20/320.

Rotorcraft: gains Flight (Winged) with Air Move 3/96.

Spacecraft: (requires Jump Jets): Space Move unchanged, but +1 to Hnd and SR while in free-fall.

Submarine (requires Submersible): Water Move 3/24.

Tracked Ground Vehicle: Ground Move 3/36.

Wheeled Ground Vehicle: Ground Move 2/64*.

Jump Jet Options for Modular Mecha

 Yes, I'm on a roll with adding new options for David Pulver’s Modular Mecha (Pyramid volume 3, issue 51).

Chemical Rocket: A simpler and lighter design than a nuclear rocket, but less fuel-efficient. Performance and endurance is the same as standard jump jets (they use a smaller motor and carry more fuel), but the mecha gains the Fragile (Flammable) disadvantage, and each extra tank of fuel adds only 40 seconds of endurance (800 yards/second ΔV). However, the exhaust is cooler and not radioactive. Reduce exhaust damage to 6d and the bonus to detect it with infrared to +2.

Ducted Fan: Requires no fuel and has a cool exhaust (damage becomes 3d crushing dkb, no bonus to detect with infrared) but needs a lot of power and only works in an atmosphere with density of 0.1 atmospheres or greater. Move is the same as standard jump jets, but treat each second of use as one shot from a beam weapon.

Fusion Rocket: A weaker but more efficient nuclear rocket only suitable for space travel. Gives 0.09 G (1 yard/second²) acceleration and 5 miles/second ΔV. Each additional fuel tank adds another 20 miles/second ΔV. Use Piloting (Low-Performance Spacecraft).

HEDM Rocket: High-Energy Density Materials are highly unstable, but give better fuel-efficiency than conventional chemical rocket fuels. Performance is the same as standard jumpjets but endurance increases to 80 seconds (1,600 yards/second ΔV) and each extra tank of fuel adds another 120 seconds (2,400 yards/second ΔV). The exhaust is no cooler than that of a nuclear rocket, but isn’t radioactive at least. The mecha also gains the Volatile feature without any reduction in DP.

Jet Engine: A turbojet with afterburner is heavier than a nuclear-thermal rocket of the same thrust, but more fuel-efficient. Performance in air is the same as standard jump jets, but endurance is increased to 5 minutes and the exhaust has the same benefits as that of chemical rockets. The mecha gains the Fragile (Flammable) disadvantage, and can only fly in an atmosphere containing oxygen with at least 0.1 atmospheres pressure. Each additional fuel tank adds 20 minutes endurance.

Nuclear Air-Ram: Although barely capable of take-off in standard gravity, and useless anywhere without an atmosphere, this gives an endurance of one year! Reduce air move to 12/48.

Note: the numbers given are only somewhat consistent with those in sources like GURPS Spaceships and GURPS Vehicles, and weren’t really checked carefully. In the kind of cinematic setting which flying mecha are expected to exist in, this shouldn’t be too much of an issue. Back-of-an-envelope calculations suggest that the existing jump jet rules are extremely generous. A more realistic (and still fairly generous) take would reduce air move to 12/48 (nuclear air rams would drop to 7/36, making them incapable of vertical take-off on Earth).

More Features for Modular Mecha

A few new options for David Pulver's Modular Mecha (Pyramid volume 3 issue 51). 

Access Space (1 DP): The mecha has a relatively roomy interior, allowing crew to carry out repairs without leaving the vehicle.

Grippers (−1 DP): The mecha has crude gripping claws instead of hands. Treat it as having Bad Grip 1 and Ham Fisted 2 (instead of Ham-Fisted 1)

Electromagnetic Armor (1 DP): This system draws on the mecha’s internal energy bank in the same way as a beam weapon. It activates automatically when the mecha is hit and stays active for 1 second, consuming one ‘shot’ of energy. During that time the mecha’s DR is tripled (instead of doubled) against shaped charge and plasma attacks. May not be taken alongside the No Laminate feature.

Enhanced Reactor (1 DP): The rate at which the mecha's energy bank recharges is doubled (i.e. 1/15 of full capacity every second).

Expendable ECM (1 DP): Numerous small launchers capable of deploying chaff, decoys, expendable jammers, and smoke. When activated gives −10 to all electromagnetic senses (including normal vision, hyperspectral vision, thermal imaging, and radar) within a 50 yard radius (centered up to 50 yards from the mecha) for 1 minute. Can be used 4 times (reloads are 200 lbs. $5,000 per use).

Extra Arms (1 DP, can be taken twice): The mecha gains an extra arm. Alternatively, it gains two additional arms, but they have the limitations given for Short Arms (below).

Extra Energy Banks (1 DP, can be taken twice): The mecha gets three times as many shots from its beam weapons and triples endurance when operating on auxiliary power. This increases to five times as many shots and quintuple endurance if this feature is taken twice. Recharge is still only 1/30 of the original figure (i.e. it takes 90 or 150 seconds of inactivity to recharge fully).

Inferior Sensors (−1 DP): All sensors have their range or magnification halved. Reduce any Acc or skill bonus by 1.

Jumping Legs (1 DP, can be taken twice): Extra-powerful leg motors grant Super Jump 1.

Short Arms (−1 DP): The mecha’s arms all gain the Short and Weak (half body ST) limitations. They may not have weapons mounted in them, but may carry them if their ST is sufficient.

Superior Sensors (1 DP): All sensors have their range or magnification doubled. Increase any Acc or skill bonus by 1. 

Unstabilized (−1 DP): The mecha lacks advanced stabilization systems, so it does not have the benefit of weapon stabilization and reduces its SR by 1.

Weak Strikes (−1 DP): The mecha has no Striking Strength bonus.

Wings (2 DP): A set of folding wings grants Flight (with the Gliding and Winged limitations). Add Wi to the mecha’s hit locations. Wings have DR 30. Most useful when combined with jump jets, doubling endurance in atmosphere.

Bigger Modular Mecha

 The mecha in Modular Mecha (Pyramid volume 3 issue 51) are fairly small (17-33 feet tall and 25-65 tons) compared to those seen in some franchises. For example, Gundam mobile suits are about 60 feet tall, pacific rim jaegers are 240-280 feet tall, and Warhammer 40,000 titans range from 40 foot tall ‘scout’ titans to the imperator class, which are at least 200 feet tall.

To make a ‘giant’ mecha, increase SM by 2, decrease Hnd by 1, double height, ST, HP, and DR, and multiply LWt. Load and Cost by 8.

A ‘colossal’ mecha increases SM by 4, reduces Hnd by 2, multiplies height, ST, HP, and DR by 5, and LWt. Load and Cost by 125.

A ‘titanic’ mech increases SM by 6, reduces Hnd by 3, multiplies height, ST, HP, and DR by 10, and LWt. Load and Cost by 1,000.

The mass of weapons carried can increase by the same factor as Load. A simple rule of thumb for scaling up weapons: multiply calibre, damage, range, and ST by the same factor used for the mecha’s height, ST, HP, and DR (e.g. a giant particle beam does 5d×40 (5) damage, has Range 12,000/36,000, and ST 200). Raise Acc by the amount the mecha’s Hnd was reduced (e.g. +1 for a giant weapon) and increase Bulk by the increase in the mecha’s SM (so giant weapons have Bulk −12). Weight and cost increase by the same factor as the mech’s.

Alternatively, a mecha can mount an array of smaller weapons instead of one big one. A giant mecha can mount 8 normal mecha weapons instead of one giant one. A colossal mecha can mount 16 giant-sized ones instead of one colossal one, and a titanic mecha can mount 8 colossal weapons instead of one titanic one. Such weapons are usually linked, so simply multiply RoF and shots by the number of weapons.

A giant mecha can have up to 4 crew without taking the Occupancy +1 feature, while a colossal one can have up to 25 crew and a titanic one up to 100. This number can be doubled by taking an Increased Occupancy feature (this is identical to Occupancy +1 except it adds more crew stations). Whether additional crew are actually required depends heavily on the setting.

Movement is also setting dependent. In some, even very big mecha move like humans, so multiply Move by the same factor as height, ST, etc. In others, larger mecha are slower and more ponderous: Move becomes 8/12 for giant mecha, 5/10 for colossal ones, and 3/9 for titanic ones. The Move ±5 feature becomes Move ±2/3 for giant mecha, Move ±2/4 for colossal mecha, and Move ±1/3 for titanic mecha. Jump jet movement is typically not adjusted for size.

Multiply the range of any sensors or communication systems by the same factor as the mecha’s height, ST, etc. The Acc bonus they grant is increased by the same amount as the mecha’s Hnd was reduced by.