Identifying Eldar Grav Tanks
This post is intended to acquaint you with the vagaries of the Eldar Grav Tank force. There are three types of Eldar Grav tanks: the Falcon (top left), the Wave Serpent (top right), and the Fire Prism (bottom).
Common Features of Eldar Grav Tanks
The grav tanks share some degree of common ground with each other.
All three are Fast Skimmer Tanks. This means they can move 6" and fire everything, or move 12" and fire one main + all defensive weapons. They may move flat-out at 18-24" and gain a 4+ cover save. They may also move over terrain with impunity. Finally, they may tank-shock and ram, as they are tanks.
All three grav tank chassis have an armor profile of 12/12/10.
All three kits are built along the same lines; a Wave Serpent chassis is just a falcon/fire prism body with an extended butt, energy field gubbins, and a smaller turret. The chief difference between a fire prism and a falcon is that the prism has a (gasp! Shock!) giant prism stuck on the turret where a Falcon has a slender gun.
Chin Gun Options
All three tanks have a twin-linked shuriken catapult (12", Assault 2, S4 AP5) mounted under the cockpit, and they may spend 10 points to upgrade it to a shuriken cannon (24", Assault 3, S6, AP5).
Obviously, something sets each tank apart in the field. The Wave Serpent is a high-capacity transport with nasty defensive upgrades and the capability to mount accurate weaponry. The Falcon dumps the defensive upgrade and downsizes the carrying capacity in order to mount two heavy weapons. The Fire Prism has no carrying capacity, and instead packs a versatile long-range gun.
The Wave Serpent
The only way to take a Wave Serpent is as a designated transport, though just about any Eldar unit CAN take one unless it's jump infantry or mounted on jetbikes. Of course, you don't have to use the folks that called for it in the thing.
The Wave Serpent can carry 12 models, or 5 Wraithguard + 2 characters. It has a single ramp on the back.
The Energy Field
This is by far the most annoying thing a number of opponents face on the Wave Serpent. The energy field is a nasty, nasty piece of kit. Its 'cheese' is denying your opponent their 'cheese', as it were. The energy field covers the front and sides of the Wave Serpent, and has no effect against melee attacks.
Effects of the energy field:
-All incoming fire is capped at S8; so lascannons, rail guns, and venom cannons are reduced to S8
-No incoming fire ever rolls more than 1d6 penetration; meltaguns within half-range and ordnance still only get Strength + 1d6
As you can see, the energy field hampers a number of anti-armor properties of weapons. However, it's still on an AV12/12/10 tank. Additionally, it does nothing to autocannons; S7 shooting can be had in volumes sufficient to overwhelm the tank (IE: Lootas, massed Guard autocannon, even Havocs if you run into those).
The Wave Serpent must mount a single twin-linked weapon system in the turret, and it may exchange its twin-linked shuriken catapult for a shuriken cannon under the nose. The Wave Serpent is BS3. As such, each shot from the turret has a 75% chance to hit, and if you take the shuriken cannon on the nose, each shot has a 50% chance to hit.
Wave Serpent, twin-linked bright lance, shuriken cannon upgrade = 145
This variant sits back and holds shooty troops.
Wave Serpent, Twin-linked shuriken cannon, Spirit Stones = 110
This model is solely for getting a target to a location. Splurge on a second shuriken cannon if you find the points.
The Logic of the Weapons Loadout
The Wave Serpent and Falcon have a turret hardpoint, and may fill it with a variety of weapons. The question that needs to be answered is why pick a given weapon for the hardpoint? In particular, many of you will note that the bright lance is an expensive piece of kit; it's 45 points.
10 points for three S6 shots out to 24". It's the cheapest option, but it's also the shortest-ranged option. If you're going for heaps of S6 shots, get a scatter laser.
However, as a chin gun, it means your tank has an extra weapon of consequence. Loss of the turret weapon certainly harms the tank, but if you still have an S6 gun, you can still dump wounds on most anything and you can still threaten lighter vehicles. As such, I find 10 points for the gun a small price to pay to keep my tanks relevant. Additionally, if they move 6", then they get more annoying shots. If your main weapon is anti-tank like a bright lance, you can score some more S6 hits on the tank, or potshot some infantry. For the versatility you get over the amazing twin-linked Shuriken Catapult, it's not a bad buy for 10 points.
Four S6 shots out to 36", albeit with a mighty AP of 6. If you had to choose between this and a shuriken cannon, you best find the points for this. It's capable of wounding monstrous creatures and threatening light armor, though of course AV12 and above just kind of laugh at it.
Eldar Missile Launcher
It's a measure of versatility: S8 AP3 krak missile, or S4, AP4 small blast, pinning plasma missile? You pick. The problem is that it's just one shot, and S8 is so-so at taking out tanks. It also has a solid range of 48".
S6, AP2, and two shots. It's got the AP you desire and the ability to negate Feel No Pain. However, there's plenty of cover, and you have fewer shots. Unless you absolutely need to negate FNP, then I'd take a Scatter Laser over this, since it's twice the shots at 36".
It's invariably the most expensive gun you can slap on your tank, and it's only useful for splatting tanks and monstrous creatures. It's S8, AP2, and most importantly it's a Lance. The 'lance' special rule means that AV13 and AV14 count as AV12 to the Bright Lance, so it is capable of penetrating Predators, Soul Grinders, Land Raiders, and Leman Russes with the same ease it has against AV12, which is to say 50% of the time.
Why the Bright Lance on the Wave Serpent?
It's the most accurate place for a Bright Lance in your army; twin-linked BS3 hits 75% of the time. BS4 bright lances hit 66% of the time, and I suppose you COULD give a Wraithlord a twin-linked bright lance (and he'd also cost 170 points...) but I wouldn't do it. Still, Wraithlords can mount BS4 heavy weapons, but they're another matter in building.
Additionally, at range, it's one of your two ways of really killing heavier tanks with Grav Tanks.. The Fire Prism is the other. Otherwise, your army has to bring Fire Dragons to reliably drop armor, and their fusion guns are considerably shorter-ranged. Note that I equate 'reliable armor killing' with 'AP1 hits' and will always do so.
The Falcon is a mixed-role tank. It has a carrying capacity of six infantry, and cannot carry Wraithlords. It is also solely a Heavy Support choice. The Falcon effectively trades carrying capacity and the energy field for more guns.
Arming the Falcon
The Falcon's 'special' gun is the Pulse Laser. It is an S8, AP2, Heavy 2 gun. It's effectively a two-shot krak missile launcher; technically it's derived from a Bright Lance but they traded the Lance option for an extra shot.
You'll want that extra shot, since the Falcon has an almighty BS of 3. If you've got Guide laying around, the Falcon certainly won't protest.
The Falcon must take a weapon from the same list I've gone over. Basically, the Falcon is more of a gunboat that wants Guide than anything else, though it can pull double-duty hiding a scoring unit with the holo-field.
Falcon w/ Pulse Laser, Eldar Missile Launcher, twin-linked shuriken catapult.
Cost: 135 points.
It sits in the back, gets Guide, and hunts medium-weight armor. It has a better volume of S8 fire than the Serpent, and I've foregone the Shuriken Cannon here to save points. You can always put it back on in order to get another gun, but you've got a 48" standoff. Your call, as points dictate.
Pulse Laser, Scatter Laser, Shuriken Cannon
It's the light show. Give it guide, watch stuff eat lead. It can do medium-weight armor (kind of), but will heap wounds on monstrous creatures and infantry. Downgrade the turret scatter laser to a shuriken cannon if you want to, to save yourself some points (...and a shot, and a foot of range.)
Dverning's Defensive Falcon
This is an idea I'm willing to test out, and I'll mention it here so you don't need to sift through comments.
Falcon, Holo-fields, spirit stones, Bright Lance = 190
It sits back, is annoying, and holds Dire Avengers to be scoring. Five Avengers as troops cost 60 points, so the Score-Falcon really costs you 250, a troops slot and a heavy support slot. I suppose it's comparable in tactical role to a standard Land Raider with a troops unit inside.
Pulse laser, scatter laser, shuriken cannon, holo-fields
It sits in the back, holds a minimal Dire Avenger unit, recieves Guide, and generally tries to shoot things to death. If possible, it grabs cover and Fortune as well.
But wait, you're forgetting defensive options!
It's true, there are other options that the tanks can take. I tend not to take them.
10 points to turn 'stunned' results to 'shaken.' I would take this more if there wasn't a 1/6 chance of being 'stunned' on both a glance (shaken on a result of 1-3, thanks to the glance's -2; stunned on a 4) and a penetrating hit (stunned on a '2' only).
You just won't get a lot of mileage out of this upgrade. You'll be annoyed when it happens, but it doesn't happen that often.
The tank may move 12" in the shooting phase in lieu of shooting. They cost 15 points. It's not necessarily a BAD upgrade, but it's more a question of how often you'll need 36" instead of 24". There are some guys who like 'em and use 'em, but I've usually done fine without them.
One use could be last-minute objective grabs, but the problem with last-minute grabs is that you don't always know if it's the last minute or not: random game length means that sometimes, it's safe to run that transport up on an objective near meltagunners (or in the line of fire of some nasty anti-tank) if you had second turn, and sometimes...it'll cost you.
The other option is if you want REALLY rapid re-deployment. I'm not much acquainted with the need for it, but I'll concede that it's possible.
If you moved flat-out and would die from an immobilized result, the vehicle instead is immobilized. This is a 20pt upgrade. It will protect you 1/6 of the time against penetrating hits and 1/6 of glances when moving fast. You DO have a 50/50 shot of biting it on a penetrating hit when moving flat-out, as you're immobilized on a 4 (which destroys you in that case) and just plain killed on a 5 or 6.
Bottom line? It benefits you 1/6 of the time in a certain situation. I don't think I'd take it.
This piece of kit LOOKS sick. It's 35 points, but it forces the enemy to roll two dice on the damage table and take the lower one.
To be honest, this kit was a lot cooler back in 4th when Eldar tanks carried Spirit Stones and always moved 12" and could only be glanced; it pretty much guaranteed that any Eldar tank would only ever get glanced. There are horror stories of a Falcon rolling up to an Imperial army gunline, taking all their gunfire, and losing a gun and being shaken. It promptly crapped out Harlequins and ran way while the Harlies proceeded to maul the Imperials.
Now, in 5th? It's not as cool as it used to be. This fellow has a neat little table of 2d6 odds.
On a glance...a 1-3 is shaken, 4 is stunned, 5 is weapon-destroyed, 6 is immobilized.
That's normally a 50% chance to shake, and 16.67% chance of stun/weapon destroy/immobilized.
With the holo-field, glances look like...
75% chance of shaken.
13.8% chance of stun
8.3% chance of weapon loss
2.7% chance of immobilized.
So a holo-field means that most of the time a glance will be a 'shaken' result. If you're inclined to take Spirit Stones, then it means that 88.8% of glances are shaken results. Ok, you kept your tank moving most of the time for 45 points.
Let's say your tank is penetrated and didn't go flat out. There's a 33% chance you'll get killed (5-6 means wrecked or exploded), a 33% chance to get damaged (3-4 = weapon destroyed or immobilized) and a 33% chance to get annoyed (1-2 = shaken or stunned).
What does the holo-field do to that?
30.5% chance of getting shaken.
25% chance of getting stunned
19.4% chance of getting a weapon-destroyed result
13.8% chance of getting immobilized
8.3% chance of wrecking.
2.7% chance of exploding
So, you go from a 33% chance of dying to an 11% chance of dying on a pen. You've a 33.2% chance of getting damaged, and a 55.5% chance of getting annoyed.
Well...partially. Holo-fields are truly nasty against low volume-of-fire, non-AP1 shots. Autocannons can come in enough volume (IE: Lootas) to overwhelm your holo-fields. AP1 on holo-fields means you've got a 25% chance of killing the tank outright rather than 33%. It means there's a 72% chance of maiming up the tank (weapon destroyed/immobilized).
EDIT: I have to say that I've changed my mind on Holo-fields. They have their place on the falcon in some builds.
Final Thoughts on Vehicle Upgrades
The real reason I don't take a lot of the Eldar vehicle upgrades is what they do to the cost of a tank.
Consider the Wave Serpent. At 145 in the aforementioned twin-bright-lance + shuriken cannon build, it's a reasonably survivable tank. I can dump 10 points into Spirit Stones, 20 into vectored engines, and 25 into star engines to have a supremely mobile tank...and make it cost 200 points. Wave Serpents will never be 200 points of cool.
Consider the Falcon...I dump all four vehicle upgrades into it and it suddenly costs 200+ points.
Really...would you rather get a marginal quality increase, or take more vehicles? I'd rather get more vehicles. Spirit Stones and Vectored Engines only come into play 1/6 of the time. Star Engines....take 'em if you really want to sack some shooting and go 12" more, for when 24" a turn just isn't enough.
Take the fewest upgrades you really need. Spirit Stones and Vectored Engines can usually be left off the tank. Turbo Boost + Fortune = durability, and fortune on a seer isn't hard to wrangle. Star Engines...some people swear by them. I am not one of them. Know that you might not use them that often, but some like Fritz swear on them over their firstborn.
So, on to our final happy little tank...
The Fire Prism
You take a Fire Prism for one reason: the prism cannon. The tank can't carry any infantry, and can't take any additional guns, but it CAN take the chin-mounted shuriken cannon.
Amazingly, the Fire Prism is BS4. Someone learned to work the targeting controls, apparently...
The Prism Cannon
60" range, and two modes of fire. There's the Focused Shot, which is S9, AP2 on a small blast template. Then there's the Dispersed Shot, which is S5, AP4 on a large blast template.
The Focused Shot means you can go tank-hunting, though it's not AP1. It also means that if someone drops something like Terminators near you, well...you can drop this on them and make them cry if you hit. It's kind of painful...and amusing.
The Dispersed Shot lets you punish infantry in the open, and make them sweat a bit in cover. It's especially fun if your enemy has failed to spread out infantry, or if you spill them out of a transport into the 'group hug' formation.
Fire Prisms may also buddy up and shoot: they have some wonky contributing-fire rules. Essentially, if one Prism can see another, it can choose not to shoot its prism cannon to increase the strength and AP of a fellow Prism's shot (IE: Focused at S10 AP1, or Dispersed at S6 AP3).
In short, the Prism Canon gives the Fire Prism some solid versatility, and the 60" range means you can sit back and pop shots out of range of a lot of enemy anti-tank fire. Taking one keeps the other guy honest with infantry 'til he takes care of the Prism Cannon; taking two gives you redundancy and the ability to combine fire. Taking three makes you no friends.
Equipping the Fire Prism
There's really not a lot of rocket science to this. I highly recommend going with the underslung Shuriken Cannon so a single weapon-destroyed result doesn't render you irrelevant as a shooting threat, and at BS4 you might hit some shots. It makes the Fire Prism cost 125 points.
It must be noted that you do NOT want Holo-fields on the Fire Prism, since it makes it more likely that you'll lose your Prism Cannon. Ordinarily it's a 1/6 shot, but the 160pt holo-fielded Prism has a 19.4% chance of losing it. Plus, honestly, the strength of the Fire Prism is that it's cheap, long-ranged, and multi-purpose.
Grav Tanks in your builds
I've done a decent amount of tinkering and playing with mechanized Eldar, and found that they're in general a pretty solid build. I have to give a nod to Stelek for piquing my interest in 'em with some of his comments and notes; my original foray into the dreaded mech-dar involved a mutation of one of his lists.
You will be able to get Wave Serpents on your troops easily. Anyone but Rangers can be mounted in them. I bring twin-bright-lance serpents (with underslung shuriken cannons) loaded with Dire Avengers. Why?
Wave Serpents can threaten any armor on the field with their Bright Lances. Dire Avengers can do their work at 18", which means I don't have to get my serpents TOO close to the enemy. Furthermore, Wave Serpents can sit near objectives, and can be quite nasty to dislodge.
Additionally, you can screen your non-Serpents with Serpents to grant them cover saves. This doesn't work well against Vendettas or heavy weapons at height, but it is an option to consider vs. tanks and infantry on ground level floors.
Falcons have their place in a full mech army. A Falcon with some gun upgrades, holo-fields and a 5-man Dire Avenger squad (and perhaps even a farseer) can sit in the backfield on/near an objective, absorb some fire, and claim/contest objectives in a pinch.
If you want a Score-Falcon, splurge on durability. Holo-fields are well worth it, and then go with either a missile launcher (if you want guided S8 fire) or Scatter Laser (if you want torrent) and the shuriken cannon. It runs you about 175, but these things can frustrate your opponent with Holo-Fields.
If you want Dakka-Falcons, keep 'em cheaper. A couple shuriken cannons, or a shuriken cannon and scatter laser provide you with plenty of gunfire and cost 130-140. Give 'em guide, and it's basically a Marine Predator with more strength and speed in lieu of BS and armor. (but, better flanks.)
Falcons could theoretically fight with Wave Serpents as Fire Dragon delivery systems. Both should get a fortuned cover save from the Farseer + Turbo Boost move, and then it's a question of AV12 Energy Field vs. AV12 Holo-Field. The Energy Field beats out melta, and I usually expect folks to bring melta. Thus, Falcons for me have become Score-Falcons.
Fire prisms are arguably the simplest tanks to use: sit back and slam something with a Prism Cannon. Hide when stunned.
When both weapons are blown off, ram someone. At range, a Fire Prism can easily crank out an S10 ram (+1 for tank, +2 for AV in the front above 10, and +1 for each full 3" you move, and you can easily move 21-24 inches...). It's highly amusing to pull off, but not necessarily what I'd chose to do with my tank. (Unless someone blows off the weapons.)
Eldar Grav Tanks in summary
All Eldar grav tanks are fast skimmers with armor 12/12/10.
Wave Serpents can carry accurate Bright Lances and infantry, and their Energy Field can be highly annoying to deal with.
Falcons can be optimized to hunt lighter armor and infantry. They compete with Wave Serpents as transports, and Wave Serpents beat them for getting close to melta weaponry. Alternatively, Falcons are better holding small troop squads and claiming/contesting objectives.
Fire Prisms can threaten anything on the field from a solid 60" away.
All grav tanks really kind of hate autocannons en masse.
Acknowledgements to Stelek, Dverning and King Elessar, as I must cite them as influences in my Eldar stuff in general. Edits in general