Partly inspired by Phobos's post
http://bg.battletech.com/forums/aerospace/the-ultimate-dedicated-ground-support-small-craft-series/, I started wondering if smallcraft could really change the tactics of ground combat. The answer seems to be 'yes' if I understand the rules correctly. Consider the following.
Poltergeist
200 Ton spheroid smallcraft 3025 with Inner Sphere technology
3 Thrust
5 Max thrust
5 Integrity
760 fuel points
5.16 Burn-days
Armor:
77 Nose
77 Left Side
77 Right Side
77 Aft
Cost 11029.5K
BV 1012
Tons Component
39 Engine
9.5 Fuel
0.5 Pumps
2 Structure
1.5 Control Systems
25 Crew (5 steerage quarters, 3 crew, 1 gunner, 1 drone operator)
2.5 Drone Carrier Control
18 Armor
17 Heat Sinks (24, including 7 free)
60 4x Thumper Artillery (only usable on ground as per Fortress dropship)
12 Ammo (60 shots each)
13 Cargo
There are about four keys to the Poltergeist design.
The first is a 'scoot' maneuver. Aerospace initiative always beats ground force initiative. As a consequence, if threatened by ground forces, the Poltergeist can liftoff, gaining 1 altitude for 2 thrust points, side slip 1 battletech sheet for 3 thrust points, then descend and land for free. Since this is a spheroid dropship, it can land almost anywhere. The scoot makes the Poltergeist essentially unhittable by conventional forces.
The second is the Thumper Artillery which has a range of 21 boards (=357 hexes) doing 15 points of AE damage in the central hex and 5 points of AE damage in adjacent hexes. The downside of artillery is that it is somewhat inaccurate and shots resolve 1 or more rounds later, so you must guess where the enemy will be. The upside is that to-hit modifiers imposed by the target do not apply---you can hit the Locust as easily as the Atlas. Thumper artillery also supports cluster munitions which do only 10 AE damage, but kill infantry units not in buildings, resolves attacks on mechs with an expected 1.666 points of head damage, while vehicles have an expected 0.333 critical rolls per hit. Both cluster and regular rounds also function as Flak. There are special rules for Flak artillery attacks, but they remain plausibly effective against airborne units.
The third key is the combination of a drone carrier control system and the cargo space for a VTOL drone. The primary function of the drone is as a scout for the artillery. It discovers the enemy, and then the mothership delivers the pain. There is no vehicle bay obviously, so the deployment mechanism is cumbersome---you carry the drone in cargo, and deploy it on the ground. Using fractional accounting rules, you can make a cheap 3-ton 25/38 VTOL drone that is armored against small-arms and imposes a +7 to-hit penalty routinely via movement. But, there is more---a drone moves at the same time as the carrier control system, and (hence) always moves after ground units while the Poltergeist is aloft. Combining with the speed, this means the drone can stay beyond long range in plausible circumstances.
The fourth key is endurance. Every crew member is allocated steerage quarters implying 40 days of life support per ton of consumables. As a smallcraft, it has some integral support provided by the crew. The engine can provide thrust for 5 days. The VTOL is fusion based and hence range unlimited. The thumper artillery uses ammunition, but it's very miserly at 20 shots/ton. And there are 10 tons of free cargo space left over after leaving space for 1 drone. In short, this is a self-contained long duration unit.
There isn't a good parallel to the Poltergeist as a unit. It's faster than almost all ground units, delivers lethal attacks at ranges beyond what nearly all other units can hope to match, has high endurance, and can "drop" from deep space.
What's the downside? The Poltergeist is useless against an underground or underwater enemy. The Poltergeist is useless against aerospace units while aloft. The artillery inaccuracy makes use in urban environments impose high collateral damage. The Poltergeist is poor for "hold-at-all-costs" operations against a close assault. These are nontrivial downsides, but the upsides of general ground combat capability seems imposing.
Edits: fixed typo and realized that cluster rounds only do 10 damage.
