Recently, I thought about why the Tau would use bipedal walkers as opposed to quadrupedal walkers (or vice versa!). So I wanted to hear ATT's thoughts on it...
please, contribute your thoughts on anything related to this topic. Why one or the other is preferable, from a physics standpoint, background standpoint, et cetera.

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Custom Units
As we all know, custom units are not allowed on ATT - unless they are of a very high quality. So if you convert up a 4-legged crisis suit, please share!
But don't post you five-minute idea for a Kroot close combat monstrosity or some crazy beast armed with twin linked Peregrine rifles...

However. I think that a general discussion on how quadrupedal walkers would perform in-field, compared to bipedal walkers, might be OK - But I will leave that up to the mods to decide.

If they do allow such a discussion, put effort into you posts - even more so than you would do with topics that are not on the border of being disallowed!

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OK, I'll start.
First of all, I think that the reason we have bipedal walkers is because they are more appealing to the Anime crowd - let's face it, Tau were created to draw in those very people.
But if we were to consider it as if we were Fio deciding on whether to create bipedal or quadrupedal walker prototype:

Bipedal
Pros:
Possibly easier to pilot, as it mimics Tau's natural mode of locomotion.
Smaller footprint - potentially easier to maneuver in dense environments.

Cons:
Less stable.

Quadrupedal
Pros:
Possibly easier to pilot, as you don't have to worry as much about balance.
Lower height - can more easily make use of cover.
Potentially, it could have a higher land speed from four legs rather than two.
More stable - greater weapons load, more even distribution of weight.
Better able to maneuver in rough terrain - four legs are better than two when going uphill and through dense underbrush and such.

Cons:
It almost has to be significantly larger.
Less suitable for dense environments (because of size).

Note that I'm not taking into account jetpacks. (Which - could quadrupedal walkers have jetpacks? I'm inclined to say yes.)
But, it seems to me that a 4-legged walker would function better than a two-legged one in most cases. If it could use jetpacks, then it would be better in almost any situation.

And one final question - how would large quadrupedal walkers compare to tanks? It seems to me that when comparing a walker and a tank of comparable sizes:
1. Tanks would be faster.
But how much faster? Tell me you can't form a cool mental picture of a 30-ton, 4-legged, animalistic walker changing at 50 mph. I can. It's awesome.
2. Walkers would be more maneuverable.
Tau tanks can only change direction but changing the direction of thrusters and their output. All walkers have to do is stick a leg out.
3. ...But tanks can fly.
The advantage here is obvious. Even if walkers did have jetpacks, they would only be able to stay airborne for a short amount of time.
4. Walkers would be more durable.
As Tau vehicles are skimmers, they rely mainly on speed to avoid damage. While Hammerheads do have impressive armor for skimmers, walkers would have better. Also, walkers can't crash and burn.
5. Walkers would have better armament.
As they are on the ground, and stable, they would be able to fire more and heavier weapons.

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So! What do you guys think? Discuss!

As Militant.Jester has already requested, please as such posts will not be accepted.

An example of a quadrupedal Tau walker: http://i174.photobucket.com/albums/w108 ... mplete.jpg by our very own Shas'ui mangozac.

E.

IMO, a bipedal walker is more effective for the role they have in mind for them. First is the fact mentioned that they would be more "natural" to control using the neural interface they are using. Also, I can't really see a quadrupedal walker using a jet pack as effectively as a bipedal. In terms of the tau, given their skimmer technology, the only reason I can see for them having a quadrupedal walker would be for really heavy duty weapons that are primarily position defense but need all terrain capability (which as far as I can tell is what the conversion depicted was). Quadrupedal walkers IMO are more for large, heavy duty stuff (like the AT-AT's in Star Wars), while the bipedal walkers serve more the role they have in the tau army.

The simple answer is "none of the above", because all* walkers suck equally. Compared to a tank, a walker has a few crippling drawbacks, even if you are technically able to build one (it's a very serious question whether your legs will actually be able to carry the weight of the walker without collapsing):


1) Ground pressure. Feet have a tiny surface area compared to tracks or anti-gravity fields, so for vehicles of equivalent mass (and therefore equivalent firepower/armor/etc) the walker will be much more vulnerable sinking into soft ground and getting stuck, breaking through the surface of roads and getting stuck, etc. Alternatively, the tank or skimmer that can safely operate on the same terrain will carry far better weapons and armor.

2) Armor thickness. A tank or skimmer is a much more compact design, so there is much less surface area to protect. Therefore for the same total armor mass, the tank or skimmer will have thicker armor and far superior protection.

3) Size. A walker by definition needs to be taller to allow for the vertical movement of walking. This means that it will be more exposed to enemy fire, at least in the case of direct-fire weapons. Likewise, it will need to be wider to allow for the horizontal movement of walking, which means that you'll have problems getting your walker into tight spaces (such as a narrow street).

Now for your comments:



I can imagine this walker attempting to run at 50mph, and I can imagine it tearing itself apart in the process without my tank having to fire a single shot. Even if you have the required power supply and the legs can survive the stress involved, if you trip (such as on a conveniently placed bit of rubble), your expensive walker is going to turn into an expensive wreck. The tank, on the other hand, can simply smash through many obstacles like that, and of course an anti-gravity skimmer can just fly over them.



Only at very low speeds. Having legs doesn't change the fact that you still have inertia to deal with.



No, walkers would not. See above.



The opposite is actually true. A walker is a terrible heavy weapon platform. Remember, with good targeting systems, stability only matters once you fire and have to deal with the recoil. Here, a skimmer has a huge advantage: the recoil forces simply kick the tank backward*, while the walker has to absorb the entire recoil force without being pushed back far enough to snap the legs. And of course a tracked vehicle lacks the skimmer's advantage, but has a much more solid structure to absorb that recoil force.





The end result is of all this is that walkers of any kind are incredibly stupid from a practical perspective, so if you must have them, you might as well just base your design on what looks best on the table. Nitpicking over the minor details is just a bit silly when you already have such fundamental crippling flaws included.







*There are two minor exceptions. The first is of course power armor, which isn't a true vehicle. If your "walker" has to fit into and interact with spaces designed for walking humans/Tau/etc, it makes sense to give it legs and arms. The other case is many-legged walkers (think spider with a gun turret) designed for extreme rough terrain where tanks can not operate. However, this does not apply to the Tau, since skimmers solve the issue in a much more efficient way.


**Assuming the weapon mount can survive the recoil without being ripped off the hull, you can't just put a starship weapon on a Piranha and expect it to survive. However, since this problem is the same regardless of walker/skimmer/tank, we'll assume that we're talking about weapons which can safely be mounted on a vehicle of the size we're talking about.

Hmm I have just had a thought on the 2 legged VS 4 Legged suit Discussion.

A 2 legged walker has 2 weak points being its legs you take out one and its movement is greatly Hampered *this is not counting jump/jetpacks* However adding 2 more legs also added another 2 weak points because still if you take out one leg you get the same problem, But now this problem is far easier to take advantage of because as far as leg targets go you have twice as many things to shoot at and more chance to hit one of the legs.

BUT then again all our suits*excluding the XV88* have thrusters of some sort, so a 2 legged suit would have a far easier time *IMO* using it's thrusters to help compensate for the damaged leg however a 4 legged suit could have a far more difficult time to do the same.

Sure this is purely speculative since we do not possess the Tech of the Tau as such we do not really know exactly how the pilots make their suits move If it's along the lines of the heavy gear type of pilot movement to control the suit as a extension of the pilot Or if it is a strap in a seat like a Gundam *these could be wrong QUITE easily as my Anime Mech-Fu is weak* if more like the first a four legged suit is going to a much more alien concept to try and pilot. Yet since the Tau have 2 legs If like the first method of movement control would be much easier for one to master.


Just my thoughts on the matter
*I am sorry If there are any grammar problems Due to my Word programs have decided to Stop working and wish for me to use my product key again and when I do so it tells me it is already in use I suspect by ME and am not paying for word and it's buddie programs again So I used the Spellcheck in hotmail However If anyone catches anything Let me know and I can edit it *

This is not true at all.

A bipedial walker that loses a leg is at best crippled and unable to move. More likely, since even standing upright requires constant movement from your legs (seriously, this is why it's so hard to make a human-like robot), the moment that leg is taken out your walker will fall over and become a useless wreck.

A walker with four legs has a redundant leg, since three legs is enough for stability. It may or may not be able to walk, but it is at least going to be able to become a stationary weapon platform.

A walker with more than four legs has multiple redundant legs, and can continue to walk and fight even with some of its legs destroyed entirely.



Until the jetpack's fuel runs out. The fact that battlesuits bother with legs at all instead of being pure jetpack gun platforms is a pretty clear statement that fuel is limited and they depend on those legs most of the time.

You do make some great counter points Peregrine, First up the fuel/power one I could see a suit with 2 legs being far better off with the standard jetpack lugging crippled legs due to less weight and that leading to less stress on the pack itself over a extended period, A suit with 4 legs is going to be a tad heavier due to the addition of 2 legs and if it had the same jet pack as a 2 leg variant I could see it being less able to travel as far on the power/fuel contained in the suit.
But If the suit was designed to have 4 legs I guess the Jetpack would increase in size to be able to help move the additional bulk of everything to do with the suit.

And as for the first point you made about the suits with 4+ legs would the placement of the legs make a difference?

But then again having a Biped walker just wins on the grounds "rule of cool" IMO because it is scientifically stupid to make a biped walker for war due to these flaws in design. Oh and if anything Star Wars has taught me anything 4 legged walkers bad *looking at you AT AT*. But that's in a world where IG conscripts would be almost world class Snipers.

However If a suit did get to this sort of condition would the occupant not decide to ditch said suit and run for the hills/safe area?

As I understand it from various previous discussions the legs are there due to maneuverability. With gravity generators and the Sho'aun'or'es generator, there is plenty of fuel to go around. However, hanging out in mid air all the time is a great way to get shot, and is much harder to change directions and maneuver in general than having feet on the ground. Think about the difference between maneuvering in space and on the ground.

In regards to the reasons to have legs, IMO they provide a degree of versatility not present in tracked vehicles. It suddenly becomes much easier to cross terrain, fight in combat, push off the ground to get in flight, throw someone off your back, etc. Also, in terms of the Tau, the Crisis suits aren't their heavy hitters. They are meant to provide heavy support in a "'crisis", moving about the battle field and dealing with threats as they appear. Tanks aren't able to do that to the same degree. Tanks are meant more for heavy duty, less mobile, massive punch roles.

Finally, tanks have just as many weak points as walkers. Take out a tread (or thruster in our case) and that tank isn't going anywhere. Get a charge down the hatch and it is gone. Any force thrown against a tank hits it head on. Walkers, however, have an advantage. Considering the high technology of the tau, the legs don't have to have their method of locomotion located in them. That allows them to be solid throughout and actually absorb an impact and keep going. They can bend and flex at the joints, something tanks can't do because they don't have joints. This allows the walker to take a hit, stand back up, and keep going. I'm not saying it is viable with real life, modern day technology, but the tau are far beyond that, something we have to keep in mind.

Great points Kles'ro, but I still wil have to agree with Peregrine.

Walkers are inherintly fragile, and Mechwarrior comes to mind. One single, well-placed shot could bring down even an Atlas in the Mechwarrior series. And even if a walker could keep "walking" with a crippled leg, they would be unable to move fast and would be seperated and destroyed quickly.

Secondly, the recoil of any large weapon on an unstable ground might send a walker tumbiling, or crashing into a building. My bet is that a walker would be stationary for a second to fire and then run after it's shot is taken.

My friends and I have had this discussion many times (mostly due to playing the Mechwarrior series since we were in primary school). Peregrine has covered in detail all the points which make the idea of a bi-pedal and to a large extent, a quad-pedal walker totally fanciful. I feel that the ultimate nail in the walkers coffin however is the obsolescence of heavy ground vehicles. Sure, Tau battlesuits are essentially very large power armour and as such avoid the issues however Dreadnoughts, Soul Grinders, Wraith Lords and Walking-titans do not.

Walkers basically fill the role of battle tanks however they come with the added problem of having a bunch of additional weaknesses while still filling the same niche role. In the 40k world we still use tanks because adding ICBMs, cruise missiles, high altitude airstrikes, carpet bombing and chemical warfare would make for an extremely boring table top game;

The benefits of firing something unmanned and highly explosive at a target from beyond the horizon far outweigh the benefits of riding up to the target in your 100 ton walker guns blazing, cigar in mouth by every metric aside from romanticism.

I'm with Peregrine 100% on this one. The technical points have already been covered so there's not really any need to reiterate the reasoning behind those, I'd like to state that the Tau codex fluff also makes large-scale walkers a moot point.

Simply put, the Tau are all about mobility and firepower. Often these are used in opposite but complementary ways, the most notable being the tenets of the Kauyon and Mont'ka. Both demand high levels of precision, mobility, timing and firepower to be the most effective and neither really seem to suit a relatively slow or high-profile weapon system when existing Tau armour fills the role perfectly. The Devilfish hull is fast enough to chase down prey for a Mont'ka strike, low-profile enough to remain hidden when lying in wait during a Kauyon ambush and still has the capability, depending on it's configuration, to pickup troops or provide significant firepower while still rapidly falling back to an egress point for extraction.

Walkers are not stealthy while performing ambushes. They can crouch to lower their profile but then require time and power to raise over half their mass back up to full height. A walker has a lot of weight carried over fairly limited contact with the ground (ie feet) and as such each foot hits the ground with significant and frequent force depending on the unit's speed. This can be easily detected by any local enemy units, coupling with the walker's size to give it an extremely visible un-ambushy profile on the battlefield. Uncool! Large walkers are generally also not the fastest nor most maneurverable units and so are also not overly suitable for Mont'ka type operations. The Tau do not use siege warfare as stated in the codex so there's very little need for large, slow, powerful assult units like Imperial titans that require significant time to deploy and depart the theatre.

To sum it up, as much as I love mechs, titans and all big stompy things, I doubt very much that large walkers are appropriate for Tau forces. I can see maybe Knight-sized units for dedicated mobile defence very much like a large XV-88 but then much cheaper turrets are available for that and well, I don't think there's anything that a complicated walker unit can achieve that an existing Manta, Tiger Shark or several Hammerheads can't do better.

I figured I'd throw in my two cents in regards to walkers, i think the exception Peregrine listed to the walker idea stands, an effective walker would need to be an hexapod at the least and possess extremely simplified legs to eliminate them as a vulnerability. Thought maybe the short vid may help redefine the idea of the clunky WH40k walker. Shape Deposition Manufacturing, for example, would severely reduce the vulnerability of legs and help a walker become both a stable platform for weapons as well as a highly maneuverable and silent one.

http://www.ted.com/talks/robert_full_on ... ution.html

A cockroach tank with spring legs would outmaneuver a tank with as much speed without falling apart and solve the problem of target area, and still be a walker.

In 40k, when I think of quadrupedal walkers, I immediately think of the defilers (and soul grinders), which are supposed to be quite fast and choppy.

As I recall, the Tau rely upon the utilization of anti-grav tech and thrusters. Applying my knowledge of a completely unrelated universe (Star Trek, and a little bit of Stargate SG-1), the anti-grav on the Crisis (and stealth) suits probabally nullifies the weight of the suit and pilot significantly so that relatively weaker thrusts can power it much further and faster.

Getting away from that, I think that the Tau designed the crisis and stealth suits to look like a Tau does, that is like how Space Marine power armor is human-ish in appearance (with ginormous shoulder pads). They have the tech to get around all of the inefficiencies of bi-pedal locomotion.

Personally, I wouldn't model anything as a quadrupedal, just because it seems too annoying to work out the logistics of where to put the legs and all.

I've been a long-time proponent of the trusty tank versus the walker. As has been succinctly stated by Peregrine, the tank provides the optimal firing platform with a heavy payload capacity, armor thickness, and--most importantly in the case of my own ice-world cadre--weight distribution. There's nothing worse than stomping around on legs out on the ice and falling through! Walkers are also more vulnerable because of their legs; sure, if you blow the tread off of a tank, it gets stuck. But it can still shoot. Disable the leg of a walker (two- or four-legged), and the thing will fall over and be able to do nothing.

I am going to take a moment to separate "walker" armored vehicles from "powersuit" type armors, because the two are very different and it seems as though people are tossing Tau Crisis suits (and all the others) into the "walker" category, which they don't belong in. Tau suits are powered armor for the body that expands the capacity of the soldier himself, and they are not true "walker" vehicles, which fulfill a completely different battlefield function. Dreadnoughts and Sentinels from the 40k universe and the Bogatyr and Riesig walkers from Battlefield 2142 are excellent examples of actual walkers. The difference between actual walkers and powersuits is the function of their design, armor and infantry, respectively.

Now for the original matter of "four legs good, two legs bad", I am going to vaguely say that it depends on the role the walker needs to fulfill. A vehicle that needs to be exceptionally stable and carry a heavier load would be best suited on four legs (such as an AT-AT walker, as Kles'ro mentioned), while maneuverability and speed would be best achieved on a two-legged platform (such as the Sentinel or AT-ST). Granted, a squat 2-legger such as the Dreadnought would be stable and load-bearing, but it would be hideously slow as well (in comparison).

Even more legs would be ideal, as Duredhel mentioned, for absolute best stability and weight distribution, as well as for being able to survive damage to a few legs. Something like the Cybermonkey from Supreme Commander comes to mind.

Time for me to weigh in.

I am inclined to agree with Peregrine and Co., in that 9.999 times out of ten a tank is better than a walker, I do think that said walker would potentially make a more effective terror weapon, because as many have said (in the past at any rate), walkers are awesome, and a gigantic awesome walking monstrosity of doom is potentially scarier than a tank. Yes, I know next everyone is going to pounce and say that said monstrosity comically collapsing/falling over/etc. is not scary in the least, but if the technical errors could be ironed out so that a walker is a viable option, it could be quite scary-looking. And I think that if a Sci-fi faction can master Faster than Light, they should be able to make a walker work.

On the subject of Two legs Vs. Four legs, I'm in favour of four (although I must admit I've always had a soft spot for the Timberwolf/Madcat), for many of the reasons stated above (weight distribution, stability, etc.). However I have always pictured Four-legged Walkers as moving in a slow relentless plod (probably because I watched The Empire Strikes Back very often as a kid), as opposed to the fast charge people seem to have pictured.


Finally,



I want that HQ choice. That would teach people not to invest in a super-powered HQ-close-combat-monster!

This is not true. Maneuvering in space is only difficult because you have severely limited fuel. If, as you say, fuel is not a limiting factor, an anti-gravity weapon platform with thrusters pointing in all directions would be FAR more maneuverable than a crisis suit (while walking).


And let's not forget that the supposed ease of changing directions with a walker is mostly theoretical. It might work well on a flat plane in a test facility, but in the real world, a tank-weight walker is going to need to be extremely careful where it steps and how it balances its weight. Suddenly shifting its weight and side-stepping without stopping to test the terrain is a good way to end up with a legless smoking wreck.

A tank, on the other hand, does not have this problem. A tracked vehicle (especially with the dozer blades the Imperium tends to fit on their tanks) can simply smash through a lot of obstacles, while a skimmer simply ignores them entirely.



I fail to see how walking through difficult terrain is easier than simply flying a few inches above it.



Which is not required if your skimmer is already in flight.



Why are we talking about melee combat with vehicles? A few flechette dischargers mounted in the appropriate places are a much better method of removing infantry than attempting to wrestle with them with your vehicle's legs and arms.



Imperial Armour III disagrees with you, as it explicitly states that Hammerheads are faster than crisis suits (70 kph vs. 50 kph). So not only is the tank better armed and better protected than the walker, the tank is considerably more mobile as well.


Not that crisis suits are really the issue here, as the subject was vehicle-size walkers, not power armor like crisis suits.



There are three key differences here:

1) The tank will be much better protected, since it has less surface area to cover with the same mass of armor.

2) Since it doesn't have legs, the tank will have a lower profile and therefore a much greater ability to keep its vulnerable points out of sight entirely. "Just shoot the treads" isn't a very effective strategy when the tank is parked behind cover with only its turret (protected by the thickest armor on the vehicle) visible.

3) A tank that loses a track is immobilized. A bipedial walker that loses a leg is destroyed. Balancing on two legs, whether as a vehicle or a human or a Tau, requires constant motion from the legs as it is an inherently unstable platform. Even disabling the leg's movement (as opposed to simply blowing it off, which will obviously destroy a walker) will quickly result in the walker falling over and becoming a very expensive wreck.


Also, throwing charges down the hatch is a non-issue if your crew are smart enough to lock the hatches, and it's even less of an issue when your flechette discharges just ensured that the remains of the demo charge carrier will need to be carried in a bucket.





This is completely wrong.

Moving with a hit will NOT protect you, as the only thing that matters is whether the shot penetrates your armor or not. If your vehicle is still intact by the time it starts to move backwards, by definition the armor has survived and you don't really care about that shot. In fact, this "feature" is a disadvantage for the walker, since even hits that fail to penetrate the walker's armor can knock it down and take it out of the fight. A tank, on the other hand, has no need to waste time standing up before it can continue to fight.


And it gets worse: since the walker has thinner armor (for the same total armor mass) than a tank, the walker is much more likely to suffer a penetrating hit. Sure, the wreck might behave a bit differently, but does it really matter once your vehicle's crew and delicate internal systems have been destroyed. This is really just a lose-lose situation for the walker.

I will agree that on the scale of a tank, a walker is a bad idea, for all the reason's you state. They would be giant monstrosities just begging to be shot down, "Return of the Jedi" style. In the role of tanks, tanks are better. Especially with tau skimmer technology. However, note the way the tau use walkers. (Crisis suits are walkers IMO for one key reason: it is piloted the the operator, not simply an armored shell. Things like Stealth Suits or Power Armor wouldn't be.) Size wise, crisis suits are less than a quarter the size of a hammerhead, before you factor in scaling issues. If it was the size of a hammerhead, it would have all the problems you mention. The "tiny" crisis suits role is entirely separate from the "behemoth" hammerhead. It can go down alleyways, into buildings. The hammerhead can just float over head, or plow through. That is what I meant by maneuverability. Not speed, but the ability to move through any environment, rapidly navigating the worst of terrain. In the right role, walkers do have their uses.

Another factor their lesser size brings is that, what do you know, those really vulnerable legs are suddenly the size of a hammerhead's air vent. Tiny targets. If the suit gets hit by something that would blow it's leg off, it would probably just destroy the suit outright.

My final comment is regarding maneuverability in space. Sure, if you have enough fuel you can get around. But it is much harder to control your movement. Ever played the game Asteroids? Same concept applies except in three dimensions. Feet on the ground inherently provide friction, which counteracts that drifting effect.

This maby be the wrong forum to ask. You might want to ask this on WWW.classicbattletech.com I know this has been discussed there a few times. And at speeds higher than 50 mph.

Remember that they are Crisis battle"suits". Just because the Tau pilot's appendages are not in the suit's appendages doesn't mean they don't function as big humanoids. The battlesuits are successful because they resemble humanoids, which is what allows them to go in places vehicles can't (just like infantry). They aren't walkers from a fluff standpoint, and they certainly aren't according to the rules, where they are classified as "Jump Infantry (jet pack)".



I assume you're not comparing a Hammerhead to an XV suit in space, and are instead comparing running on legs to anti-grav. Considering the advancement of Tau technology, I'm sure that their mastery of hover-tech is far beyond ours and that they have a great deal of inertial control, thus are not susceptible to noteworthy amounts of antigravitic drift. The skimming aspect of Tau vehicles is actually their greatest asset, as they lack the shortcomings of both walkers and tracked/wheeled vehicles. After all, WE don't take dangerous terrain tests when moving completely through a forest or other piece of terrain.

Yet again, I start a discussion topic and never respond... until now!

Peregrine and others (but mostly Peregrine ) seem to have shot down most arguments for walkers. But I had another question: What about comparing walkers to skimmers for stealth heavy weapons?
As long as the reactor/engine was properly shielded, a walker could be practically invisible to heat sensors. And since it walks rather than flies it would be less vulnerable to radar and such as it could hide behind ground cover. Finally, it would not have thruster exhaust lighting up sensors or roasting some poor guardsmen.
*Pre-counter-argument: Peregrine said that a walker would be terribly loud and send vibrations all over the place just by walking - I think that at slow speeds this could be avoided. And you'd be going slowly on a stealth mission anyways.