Tracked Vehicles Instead of Walkers...

[Darth Judas]

They should've gone with hovertanks. No need to worry about falling into pits and whatnot, no fear of stepping on rolling logs and tipping over, or having cables wrapped around the legs, and the technology was there. And some of the larger craft, like those huge droid carriers in TPM, were able to crash through a thick forest without being forced to a stop.

[Stark]

Yeah, except it's established grav vehicles have problems penetrating theatre shields. Hence dedicated siege vehicles like AT-ATs need direct contact locomotion.

[GunDoctor]

Hybrid electric drive AFVs with band tracks can get double the performance for the same cost level.

http://www.g2mil.com/hybrid.htm

Yeah, on light M113 APCs that you can take out with GPMGs! Oh and wait, your link doesn't say anything about tracks that I can see, just that the future of Army logistics is electro-diesal engines. No shit sherlock. But I gurantee they won't be placed into main line AFVs. Not unless are brains are leaking out of ears. What happens when you need maximum power and your battery runs out? SOL huh?

"The fuel savings occur because the electric engine can operate the vehicle by itself for up to 20 minutes. "

"Whenever max power is demanded for rapid acceleration or climbing steep grades, the electric motor kicks in to help."

Sure fucking hope the battle is shorter than 40 minutes! Maybe when the next generation of tech comes out and we're talking about hours of life at full power.

But I won't be surprised if the 'peace dividend' types don't win out on this, like the assholes who want to retire the Abrams in favor of a Stryker variant. Sure, we're not facing main line tanks NOW, but who says this state of affairs will last, or that we will have time to pull a new MBT out of our asses when we need it?

[Sikon]

As another analogy, consider how car axles last much longer than 100-hours between maintenance; if anything, the optimal legged vehicle design might give a smoother ride with less vibration than a car going fast down a rough road. I am not suggesting that major bearing maintenance would be faster than replacing tracks but rather that the former could be needed much less often than the latter.

You just proved my point! Yes, car drivelines can last a long damned time because they are loaded in a uniform and controlled way.

You can not in any way consider a car driveline analogous to joints in massive legs.

I don't dispute that a sub-optimal legged vehicle design could require excessive maintenance or even more maintenance than current tanks, but this has been instead about the optimum possible with modern-day materials. After full use of foot contact velocity control, thickly padded feet, and shock-absorbers, surely good engineers could make bearings operating at a few MPa last much more than ~100-hours between maintenance, if that is made an important design goal.

Read: handwaving. I can't think of a similar loading condition and application anywhere in the field of mechanical engineering. Feel free to correct me, my knowledge isn't exactly encyclopedic, but I don't think you can come up with one either.

There is also the analogy of machines ranging from car engines to animals lasting much longer than even the ~100-hour M1A1 tracks. However, there is not going to be any practical absolute proof I can give of the preceding.

Both tremendously less massive, and so poor examples.

The loading of the giant bearings on a properly designed legged vehicle with foot contact velocity control, thickly padded feet, and shock-absorbers could even vary less over time than a car bouncing down a very rough road at high speed. The peak force on the car's axle can be much greater than the car's weight momentarily. Such is a little analogous to how a person jumping a third of a meter up and down momentarily deaccelerates at several g's or more. Yet the preceding legged vehicle concept could be more like a person walking softly with care to keep under a small fraction of 1g deacceleration.

Piston engines operate at more than the low number of MPa that could be involved, with vastly more sharp acceleration and vibration. Yes, they are smaller, but they still can have much more force per unit area. The legs of the hypothetical vehicle aren't moving up and down at thousands of rpm but rather their padded feet can slowly deaccelerate when approaching the ground.

Let's specify what you are arguing.

The following three choices cover the possibilities:

1) No leg bearings can work at all, not even for a few steps.

2) Leg bearings can be made and work, but even the most optimal legged vehicle design possible will fail or need to be overhauled within 1E2 hours.

3) Optimally designed leg bearings and legged vehicles could last longer than 1E2 hours without overhaul before then.

Obviously I am arguing in favor of option #3, but which you are you trying to support?

If you choose option #2, please explain why leg bearing designs that initially worked would have major problems within 1E2 hours in particular as opposed to an optimal design plausibly continuing to operate for any different timeframe like 1E3 hours. If you choose that option, you couldn't just say there is wear having an eventual effect. Rather, you would have to show why there would be breakdown in under 1E2 hours in particular.

Otherwise, one has little more reason to conclude all possible designs would fail within 1E2 hours than to conclude they would fail within 1 hour.

------------

I think you entered this discussion mainly meaning just to argue that a legged vehicle is an engineering challenge, in which it is easy to have excessive vibration, complexity, and maintenance. I don't even disagree with that. That much is true to some degree. A sub-optimal design wobbling and pounding its feet into the ground hard and fast with weak bearings could break down almost arbitrarily fast. However, I am just saying here that an optimally designed legged vehicle could plausibly go for more than 100 hours before overhaul, as there is not reason to assume under 1E2 hours would happen to be the particular limit for all possible designs.

[Crayz9000]

At any rate, just to butt in here with my two cents, the AT-AT does not appear well-suited to sustained operations. They just don't fit its role of an assault vehicle (get in, blow everything to hell, get out) and in between operations the AT-AT will spend its time resting aboard the Star Destroyer that brought it there.

A Star Destroyer which, coincidentally, has repair facilities on board.

Which will be standing by in orbit for the duration of operations.

Therefor, I don't think that leg maintenance is that much of a concern for the Imperials.

[Typhonis 1]

So whats the in Universe reason for the Imperials using ATATs rather than juggernauts?

[FTeik]

Since the original plan was probably an orbital bombardement instead of a ground assault Vader and Veers had to improvise and make use of what was available. What were the walkers.

[VT-16]

So whats the in Universe reason for the Imperials using ATATs rather than juggernauts?

None. They do use them, but say they are only used in outlying regions (which is bs, since they were used as part of Vader`s taskforce on Hoth, according to SW Visionaries, and shown struggling in the snow.)

[Cao Cao]

So whats the in Universe reason for the Imperials using ATATs rather than juggernauts?

None. They do use them, but say they are only used in outlying regions (which is bs, since they were used as part of Vader`s taskforce on Hoth, according to SW Visionaries, and shown struggling in the snow.)

How exactly were they struggling in the snow?
They kept a steady pace and achieved total victory for their mission objective.

[Stark]

So whats the in Universe reason for the Imperials using ATATs rather than juggernauts?

It's like you didn't even read the fucking thread.

They're more maneuverable, handle rough terrain better (for all the fucking sense that makes) and seem better suited to longrange attacks. The 30-meter Juggernaut is several times more massive than the AT-AT, and I doubt it can be directly compared. The smaller one (the 5, I think) sucks.

Whoever wrote that the Juggernauts have poor maneuverability is a retard, by the way. It's the worst bit of retcon I've ever seen: there's obviously an in-universe reason to use AT-ATs, but making the alternatives stupidly crippled isn't the way to rationalise it.

[Winston Blake]

Yeah, except it's established grav vehicles have problems penetrating theatre shields. Hence dedicated siege vehicles like AT-ATs need direct contact locomotion.

Another thing established previously was that theatre shields make conventional indirect artillery mostly useless, since the shield blocks external fire and shells don't have room to arc underneath.

[D.Turtle]

About tanks and their track's maintenance:

This is from my experience in the german army.

With our Leopards 2A4 and A6 track maintenance consisted of the following:

Removing one set of end connectors.
Driving off the track (one side if alone, both sides if you have another tank or a Büffel).
Turning the track around (requires about one tank platoon of soldiers, or the proper vehicles).
Using hammers and spikes to remove the old rubber insets.
Using hammers to put on the new ones.
Turning the track around again.
Driving on the tracks again (or pushed if you drove off both).
Replacing the end connectors.
Driving straight ahead a hundred meters and rolling out.
Tightening the tracks.

Finished.

Takes between 45 minutes or so and 2 hours (depending on what day of the week it is, etc).

If you need completely new tracks (because the old ones are too fatigued), simply drive off the old ones and drive on the new ones and tighten.

About having a driver in the back: In the german army we have one vehicle that has two drivers: The Luchs.

It is a light recon tank (being phased out), that has two drivers, so that in tight situations where a quick getaway is needed, the second driver (who is also the radio operator) can quickly drive away, without having to turn the vehicle around or the commander needing to direct the driver.

The Leopard 2A6 (and I think also the Puma, the new IFV, and the Fennek, the new recon vehicle) has a camera in the back, so that one driver can easily drive backwards too.

[montypython]

Single-piece band track system for AFVs, minimizes wear and tear:

http://www.defensespareparts.com/images ... dtrack.htm

http://www.combatreform.com/bandtracks.htm

[nightmare]

So whats the in Universe reason for the Imperials using ATATs rather than juggernauts?

None. They do use them, but say they are only used in outlying regions (which is bs, since they were used as part of Vader`s taskforce on Hoth, according to SW Visionaries, and shown struggling in the snow.)

So Hoth isn't an outlaying region now?

A few outliers wouldn't set a standard either.

But to answer the original question:

Poor terrain handling, short line of sight, poor maneuverability, less firepower, and most of all, very short operational range. 50 km if my memory serves. Additionally, the Jugg has a vulnerable sensor mast which was originally manned, and the vehicle is prone to breakdown, and very difficult to repair.

That said, as VT-16 pointed out, Juggs are still common, presumably because of a large number surviving the Clone Wars. But they are clearly being phased out and for apparently good reasons.

If you want a non-legged Imperial assault vehicle, I would look at the Flying Fortress or any of the repulsortanks. Tracks or wheels doesn't seem to be used for any other large vehicles. Century CAVs and Maulers, and the Troop Carrier, yes.

[FOG3]

In universe however using legs does increase mobility, the all terrain part of the name, meaning mainly that vehicles can cross tank pits, casms and other obstacles by stepping over them rather than needing bridge alying equipment or sappers to clear the way.
Also by elevating the main body and weaons it massively increases targeting range which would otherwise be blocked by the horizon.

Joy so now when you reach a chasm too big for your vehicle to safely cross, the Engineer Corp needs to not only make the bridge support the weight of this bloody big and resource intensive behemoth, they have to make it solid enough to take the shock loading. You just love making a Engineer's job hell, don't you?

Just think of all the resources you need to invest to get those things anywhere they'd be relevant. Just think how much firepower you could bring with conventional units deploying with just the same transport assets.

It could also render mines less effective aslong as the feet are sufficiently well armoured, the crew compartment being safely out of the blast area.

If you're investing all the resources to deploy and support that big walker, a few extra large dumb antitank mines aren't that big an investment for the OpFor. Unlike changing a track pad or road wheel, replacing a foot isn't something the crew can exactly be expected to handle in the field. As a matter of fact it's liable to lead to further damage, that may total the vehicle if you don't have enough legs left, and an intelligent enough system to compensate.

Nevermind intelligent self targetting munitions could still type class the vehicle and launch the munition where it will do the most good. Directional proton torp to the head, ala the rockets used by the Clone trooper gun ships, should make for some serious attitude ajustment.


I consider the terror business bogus. Terror is derived from capability, and what's more scary a Tank you have a halfway decent chance of taking out, or a Sniper/FO that can pick you off anytime, from anywhere. The only reason thump, thump, thumpity, thump isn't the equivalent of a dinner bell going off is due to a significant difference in equipment level preventing others from effectively dealing with the mecha. If they didn't have that significant difference the mecha would be just be a big _juicy_ target.

[NRS Guardian]

The sources seem to indicate that repulsortanks are more common than other vehicles, and that ground contact vehicles are mostly used when dealing with theater shields or situations with funky gravitics. When the Empire has to attack across a chasm or canyon that walkers can't cross they send repulsortanks and Floating Fortresses.

[Anguirus]

Reply with quote
Angurius, the Jug can't turn slowly - it can BARELY TURN AT ALL. You turn it around by DRIVING FROM THE OTHER END. Hence, almost-zero agility. This cannot be avoided. The AT-AT is *more agile*.

Is there a reason you are ignoring my example from the *films* of a Juggernaut turning to avoid crushing an AT-AP?

At any rate, a Juggernaut, A6 or A5, does not have to turn in order to blast anything around it, and it does not have to turn in order to change direction. Labeling it as less maneuverable than an AT-AT borders on the ludicrous, since we've never even seen an AT-AT complete a turn, to my knowledge. The closest we get in the films is a sort of lean, and if there's further EU information on the subject I'm not aware of it.

Also, even the gaylord EU says it sucks at non-urban environments, so clearly things like SNOW WASTES would challenge it. The AT-AT has *better terrain handling*.

Clearly, it proved effective on beach terrain. Also, can you even IMAGINE driving that thing through a city?

If you are arguing that AT-ATs are superior on terrain such as snow wastes, and not that it's actually significantly better at anything on flat terrain, then that's pretty much my whole point. I'm sure that AT-ATs are useful in certain situations, I just don't understand why they are virtually ubiquitous.

Also, there is a thread specifically about toppling AT-ATs, go read it.

Link?

It's very amusing... and you simply saying 'nah it's easy' doesn't convince anyone, champ.

I'm simply noting that they have a very high center of gravity. I'm not trying to "convince" anyone of anything, I'm simply asking a) why this vehicle exists, b) why it was built in such numbers and c) why you would use one instead of an A6 Juggernaut.

Get this: the ATAT chin guns are BIGGER and HIGHER, hence BETTER. Are you going to counter any of these points, or just say 'nah it must be better'? The AT-AT is *similar or better armed*.

Than the A6? Nonsense. The AT-AT's chin guns are no bigger than that craft's primary armament, and moreover the Juggernaut heavy laser turret is on a much more stable platform, allowing for more recoil and better cooling systems to service a heavier weapon.

The AT-AT may have more firepower than the A5, but they are most likely comparable given that the A5 is still easily as large as the AT-AT's main body and its heavy laser cannon still has a better firing platform. All of the AT-AT's artillery is packed under its chin...a significantly smaller weapons system than even the AT-TE's main gun.

You are also ignoring the advantages of having a large number of missiles. Those ports are easily large enough for proton torpedoes or similar ordnance.

PS, the only 'hideously vulnerable to starfighters I remember is getting killed by the Falcon with a supergun.

Ever read Isard's Revenge? Rogue Squadron decides to "save their torpedoes" and rip apart AT-ATs with their laser cannons. Also, several sources IIRC note that they are easily destroyed by concussion missiles, which are relatively small and portable. I'd also imagine that a Hailfire droid could have ripped apart the Hoth taskforce. All it would have to do is speed around behind the half-dozen AT-ATs visible in the film and open fire.

I don't know what your definition of a "supergun" is, but in Dark Empire a few shots from one of the Falcon's quad laser turrets blows apart the entire back half of an AT-AT walker.

Also, you're just being a troll and ignoring that it's likely these vehicles are used for ASSAULTS UNDER SHIELDS where full fighters are difficult or impossible to use. You know, with the legs instead of repulsors? The deliberately high stature? Rolling Eyes

This is honestly the first time I've ever been called a troll.

Anyway, you are telling me that the AT-AT must count on enemy shield protection? If it is an extremely specialized vehicle designed to penetrate enemy shields and dispatch a lightly armed force...then good for it, but I question why according to the literature every ISD carries these contraptions.

Just because there are things the AT-AT can do very well does not mean that it is a practical weapon. During a full planetary assault (say, similar to the battle of Geonosis) these enormous personnel carriers are nothing more than high-profile targets, and for every missile that hits home you lose a 30-meter walker, a complex drive system, two heavy artillery pieces, and forty troops. A Juggernaut has the same high profile but better weapons coverage, heavier armor, 300 troops, and greater speed.

I'm not trying to be a jerk or an "AT-AT hater," I'm just asking if there's an in-universe reason why they are so ubiquitous. In some of the literature and comics it seems as if these things are primary heavy assault vehicles of the Empire. I can't imagine them exceling in this role. If you can, please enlighten me.

[Stark]

Oh jesus. No, NOT the A6, the A6 is many times more massive than an AT-AT and direct comparisons are stupid. It's the same height, but from the ground-up instead of on legs. No shit it's more capable.

Don't blame me for bad EU information: they say the Juggernauts are poorly maneuverable. I know it doesn't make any sense. Yes, I can imagine using them in a city, because they have wheels and wheels are hardly the offroad drivetrain of choice. They can apparently make 160km/h (the a5), but I'd love to see them do that over broken terrain.

I thought in DE the Falcon had some crazy iongun thing bolted to it? And no, I would never read rubbish like Isards Revenge.

The fact that you acknowledge you're comparing the huge, 300-man A6 to the AT-AT is amusing. No shit it's better, it's HUGE. I mean, you're not justifying your laughable 'each missile will kill an AT-AT' statement, so I'm not sure why I'm even bothering.

I don't think AT-ATs should be ubiqutious. It seems to me that it's strengths and weaknesses are predicated towards planetary assaults under shields over rough terrain. It's not my fault the EU is so lame they make up retarded reasons why the Jug sucks and has every ISD carrying an AT-AT. I think using AT-ATs in ESB made sense, and I'm not going to be held to hack novels that say they're used everywhere.

[Howedar]

The loading of the giant bearings on a properly designed legged vehicle with foot contact velocity control, thickly padded feet, and shock-absorbers could even vary less over time than a car bouncing down a very rough road at high speed.

You're getting to the point of constraining your solution to a house that's walked on jacks. It's entirely possible, and I suppose it's even technically a walker, but I entered this discussion with the (perhaps silly) supposition that you were suggesting something less contrived than that.

The peak force on the car's axle can be much greater than the car's weight momentarily. Such is a little analogous to how a person jumping a third of a meter up and down momentarily deaccelerates at several g's or more. Yet the preceding legged vehicle concept could be more like a person walking softly with care to keep under a small fraction of 1g deacceleration.

See above. If you're claiming that you can build a walking house, in the loosest possible sense of the word "walking", then I guess I can't argue.

Piston engines operate at more than the low number of MPa that could be involved, with vastly more sharp acceleration and vibration. Yes, they are smaller, but they still can have much more force per unit area. The legs of the hypothetical vehicle aren't moving up and down at thousands of rpm but rather their padded feet can slowly deaccelerate when approaching the ground.

See above. Walking house.

Let's specify what you are arguing.

The following three choices cover the possibilities:

1) No leg bearings can work at all, not even for a few steps.

2) Leg bearings can be made and work, but even the most optimal legged vehicle design possible will fail or need to be overhauled within 1E2 hours.

3) Optimally designed leg bearings and legged vehicles could last longer than 1E2 hours without overhaul before then.

Obviously I am arguing in favor of option #3, but which you are you trying to support?

If you choose option #2, please explain why leg bearing designs that initially worked would have major problems within 1E2 hours in particular as opposed to an optimal design plausibly continuing to operate for any different timeframe like 1E3 hours. If you choose that option, you couldn't just say there is wear having an eventual effect. Rather, you would have to show why there would be breakdown in under 1E2 hours in particular.

Otherwise, one has little more reason to conclude all possible designs would fail within 1E2 hours than to conclude they would fail within 1 hour.

------------

I think you entered this discussion mainly meaning just to argue that a legged vehicle is an engineering challenge, in which it is easy to have excessive vibration, complexity, and maintenance. I don't even disagree with that. That much is true to some degree. A sub-optimal design wobbling and pounding its feet into the ground hard and fast with weak bearings could break down almost arbitrarily fast. However, I am just saying here that an optimally designed legged vehicle could plausibly go for more than 100 hours before overhaul, as there is not reason to assume under 1E2 hours would happen to be the particular limit for all possible designs.

I don't know. You haven't made any particular effort, as far as I can see, to support your claim. Aside from your laughable, and frankly insulting, manner of tossing around numbers, I haven't seen any real thought process other than so and so "could be possible", or such and such "shouldn't be difficult" or something or other "seems plausible". We aren't in the realm of magical mystical science fiction on this one. I don't care what materials we're dealing with. You claim that your argument was, and I quote from above,

However, I am just saying here that an optimally designed legged vehicle could plausibly go for more than 100 hours before overhaul, as there is not reason to assume under 1E2 hours would happen to be the particular limit for all possible designs.

That was not your original argument. Your original argument was that

I don't know if this would apply at all to the GFFA, but terrestrial tracked vehicles like MBTs are terribly maintenance-intensive with imperfect reliability; tracks can need replacement about every 1000km. Any large group of modern MBTs can decrease significantly from its original operational number after every few hundred kilometers traveled in battle. The Empire might prefer a lot more reliability if their armor is to be capable of traveling over a large area of a planet. Maybe legs don't wear out as fast as tracks?

That has nothing to do with materials, bud. That has to do with the straightforward design trade-offs between rotating (wheels/tracks) and oscillating transport. Yes, wheel axles are subjected to bouncing on rough roads. Legs bounce by their nature, and to suggest that this can be minimized to the point where they are superior to wheels is akin to suggesting that a turtle can squeeze through small orifices like an octopus, if only we remove the shell and bones. Well yeah, I suppose so, but it isn't a turtle anymore.

This was my original argument. It wasn't something daft about 100 hours (where that number appeared I have no idea). It was that with the same materials and conditions, rotating transport is subject to less severe stresses than are legs.

You have never addressed that in anything more than a superficial manner, and it's getting damned annoying.

[Anguirus]

Reply with quote
Oh jesus. No, NOT the A6, the A6 is many times more massive than an AT-AT and direct comparisons are stupid. It's the same height, but from the ground-up instead of on legs. No shit it's more capable.

It's far more massive, but one Venator can still hold a ton of them. I'm asking why even BOTHER with the AT-AT when an equal mass of A6s is probably going to be superior in most situations? You'd need eight AT-ATs--which seem analogous to APCs--to carry more troops than one Juggernaut, and they'd take up a hell of a lot more space in your cargo holds.

Don't blame me for bad EU information: they say the Juggernauts are poorly maneuverable. I know it doesn't make any sense. Yes, I can imagine using them in a city, because they have wheels and wheels are hardly the offroad drivetrain of choice. They can apparently make 160km/h (the a5), but I'd love to see them do that over broken terrain.

Even the A5 is rather wide for urban terrain, unless they plan to just crush everything. But then you wind up with more debris than you can handle in front of you. I'd stick with repulsorlift vehicles and heavy scout walkers for the kind of urban terrain we usually see in Star Wars.

And they may be wheels, but they are HUGE wheels. I'd say a massive vehicle that always has to keep three legs on the ground and has limited flexiblity and range of movement is an exceedingly poor choice for broken terrain. One would think that the engineering problems that have been solved with the AT-AT are far tougher than the issue of getting a tank the size of an office building tough enough to just run over everything in its way that isn't a significant fraction of its own height.

I thought in DE the Falcon had some crazy iongun thing bolted to it? And no, I would never read rubbish like Isards Revenge.

Nah, that's DEII. And you're right, Isard's Revenge is rubbish, but that particular scene serves as a good illustration. There's not much an AT-AT can do against heavy air support aside from evacuate, whereas at least a Jug can at least fire in all directions and make a run for cover. (One proton torpedo is still a kill on an A5, as we see in Rogue Squadron, but we don't know how effective fighter lasers would have been.)

The fact that you acknowledge you're comparing the huge, 300-man A6 to the AT-AT is amusing. No shit it's better, it's HUGE. I mean, you're not justifying your laughable 'each missile will kill an AT-AT' statement, so I'm not sure why I'm even bothering.

One proton torpedo or a few shots from starfighter-grade laser weaponry are confirmed kills against AT-ATs. Proton torpedoes are very small. The Hailfire carries a crapload of larger missiles that are confirmed one-shot kills on AT-TE. The back end of an AT-AT has no defensive weaponry. AT-ATs cannot turn worth shit and have a large, vulnerable fuel tank right underneath their legs (the explosion of this tank caused one to physically flip over in Isard's Revenge). Once their armor is pierced, AT-ATs tend to explode violently (ESB), even if someone throws a grenade in it.

I'd say that they are extremely vulnerable to Hailfires. I do admit that we don't know how their missiles compare to proton torps, nor do we know that one shot = one kill. It is clear that AT-ATs are in trouble if the enemy is actually willing to throw fast, maneverable vehicles with antivehicle missiles at them.

I don't think AT-ATs should be ubiqutious. It seems to me that it's strengths and weaknesses are predicated towards planetary assaults under shields over rough terrain

Then we have nothing to argue about.

[Sikon]

The loading of the giant bearings on a properly designed legged vehicle with foot contact velocity control, thickly padded feet, and shock-absorbers could even vary less over time than a car bouncing down a very rough road at high speed.

You're getting to the point of constraining your solution to a house that's walked on jacks. It's entirely possible, and I suppose it's even technically a walker, but I entered this discussion with the (perhaps silly) supposition that you were suggesting something less contrived than that.

The peak force on the car's axle can be much greater than the car's weight momentarily. Such is a little analogous to how a person jumping a third of a meter up and down momentarily deaccelerates at several g's or more. Yet the preceding legged vehicle concept could be more like a person walking softly with care to keep under a small fraction of 1g deacceleration.

See above. If you're claiming that you can build a walking house, in the loosest possible sense of the word "walking", then I guess I can't argue.

Piston engines operate at more than the low number of MPa that could be involved, with vastly more sharp acceleration and vibration. Yes, they are smaller, but they still can have much more force per unit area. The legs of the hypothetical vehicle aren't moving up and down at thousands of rpm but rather their padded feet can slowly deaccelerate when approaching the ground.

See above. Walking house.

Neither padded feet, shock-absorbers, nor the robotic control of the feet equates to what I would call a "walking house," but debating semantics is seldom productive.

I don't know. You haven't made any particular effort, as far as I can see, to support your claim. Aside from your laughable, and frankly insulting, manner of tossing around numbers, I haven't seen any real thought process other than so and so "could be possible", or such and such "shouldn't be difficult" or something or other "seems plausible". We aren't in the realm of magical mystical science fiction on this one. I don't care what materials we're dealing with.

I give illustrations with numbers since the magnitudes matter. If the numbers had been GPa instead of MPa, there would not be the same plausibility. A vehicle with kilometer-length legs would be implausible, but the situation is much different for one with 15-meter legs.

I illustrated a giant legged vehicle that could have under 10 MPa of average stress in its large legs, later implying how it could have even larger joints also operating even at under 10 MPa average stress if worthwhile. I implied how it does not have to have multiple-g accelerations. Handling such stresses is not particularly implausible when material strengths up to hundreds of MPa allow some commercial bearings to handle at least many tens of MPa.

Let's give another illustration. Imagine a small legged vehicle with a body 1 meter by 1 meter by 2 meters, with each of four leg joints being 6cm by 6cm. (Such is about 3ft by 3ft by 7ft, much smaller than a car). You may dislike my animal analogies, but, for a vehicle this small, one can see how it is not implausible compared to an elephant or a dinosaur, particularly not when steel is lot stronger than bone.

Scale it up by a factor of 10 without changing anything, and the result then would be higher stress, as 1000 times the weight would be placed on leg joints 60cm by 60cm, with only 100 times the area, giving 10 times the number of MPa stress. Yet the 10 meter by 10 meter by 20 meter giant vehicle could if necessary instead have leg joints 2 meters by 2 meters, in which case its weight would be instead distributed over 1000x the area.

Having 1000 * X weight on 2m-by-2m leg joints gives the same level of stress as having X weight on 6cm-by-6cm leg joints. The giant vehicle has 4 m^2 leg joints, while the small vehicle has 0.0036 m^2 leg joints. Suitable scaling up can not go on forever, but the legged vehicle in my example was still within a plausible size range for steel. That is how a legged vehicle with 15-meter legs can have quite a low number of MPa stress.

Compare a M1A1 and what the above sample vehicle would be like if it had tracks instead of legs. The M1A1 is 3.7 meters by 7.9 meters, with a weight of 63 to 68 tons. (The length is not counting the cannon, as otherwise it would be 9.8 meters in total). The larger vehicle is 10 meters by 20 meters but with a body weight of 1600 metric tons if one makes its body weight like the example in my earlier post. As a result, it is around 7 times the area but about 30 times the weight. With the higher weight to area ratio, tracks might last less long for the large vehicle than even their short approximately 100-hour life on the M1A1. The M113 APC of 11 to 14 tons can go 4000+ to 6000+ miles with the tracks linked to in the last post of montypython, but that is a lot different from a vehicle orders of magnitude more massive. It is possible that the giant vehicle might go longer with legs than tracks.

You claim that your argument was, and I quote from above,

However, I am just saying here that an optimally designed legged vehicle could plausibly go for more than 100 hours before overhaul, as there is not reason to assume under 1E2 hours would happen to be the particular limit for all possible designs.

That was not your original argument. Your original argument was that

I don't know if this would apply at all to the GFFA, but terrestrial tracked vehicles like MBTs are terribly maintenance-intensive with imperfect reliability; tracks can need replacement about every 1000km. Any large group of modern MBTs can decrease significantly from its original operational number after every few hundred kilometers traveled in battle. The Empire might prefer a lot more reliability if their armor is to be capable of traveling over a large area of a planet. Maybe legs don't wear out as fast as tracks?

The quote from my first post pointed out that terrestrial MBTs are maintenance-intensive and speculated on the possibility of the Empire's legged vehicles not wearing out as fast as tracks. I mentioned an estimate of track replacement of about every 1000km that was from the source given in my second post. Such would correspond to track replacement every several tens of hours. Later, you gave a source indicating that the M1A1's tracks can go for 2000 miles. In my post at 9:59pm on the 26th, I observed that corresponds to around 100 hours at moderate speed. As a result, my post before this talked about how an optimal legged vehicle design might last more than 100 hours (1E2 hours).* None of the preceding is contradictory aside from me revising the track lifetime comparison figure, which was an appropriate revision. I didn't say it was precisely my original argument.

* The GFFA might have tracks lasting much longer, but this discussion became about the situation with modern-day materials; besides, they might have better leg materials too.

My original argument was that the Empire may benefit from having some large, legged vehicles rather than just only having vehicles like terrestrial tanks. As seen in my first post, I suggested they could step over some obstacles; their legs might not wear out as fast as tracks (using the 1000km example later revised); their costs may not be directly proportional to their mass; and their high profile maximizes effective weapons range in an universe where direct-fire weapons dominate. As can be seen, my discussion with you has been mostly a tangent to my original argument, and the vast majority of what I said hasn't even been discussed. However, each of the preceding points is plausible.

That has nothing to do with materials, bud. That has to do with the straightforward design trade-offs between rotating (wheels/tracks) and oscillating transport. Yes, wheel axles are subjected to bouncing on rough roads. Legs bounce by their nature, and to suggest that this can be minimized to the point where they are superior to wheels is akin to suggesting that a turtle can squeeze through small orifices like an octopus, if only we remove the shell and bones. Well yeah, I suppose so, but it isn't a turtle anymore.

This was my original argument. It wasn't something daft about 100 hours (where that number appeared I have no idea). It was that with the same materials and conditions, rotating transport is subject to less severe stresses than are legs.

You have never addressed that in anything more than a superficial manner, and it's getting damned annoying.

The most massive example given in this thread of a vehicle using tracks, the 63+ ton M1A1, ends up replacing them every 2000 miles. You should see where the 100-hour figure comes from, as my earlier post at 9:59pm on the 26th pointed out how 2000 miles corresponds to around 100 hours of travel at moderate speed.

A track is made with flexible material stretched-out and going over the edges of rocks, debris, etc. You shouldn't just describe tracks versus giant steel legs as "rotating" versus "oscillating" without considering the other potential differences. Remember a M1A1's tracks last for merely around 100 hours. With modern-day flexible materials (like rubber), tracks on a vehicle up to a couple orders of magnitude more massive might only last for as little time or maybe even much less time...

Tracks wear out too fast for them to be just grouped into "rotating transport" as if the lifespan of a tank track is remotely close to that of a car. Perhaps their limited life is because the flexible track material can be subject to high stress relative to its strength when going over sharp edges. The ratio of that stress to the flexible material strength does not have to always be less than the stress to strength ratio in a giant thick steel leg. Whatever the cause, tracks for the heaviest vehicles last a surprisingly short period of time.

EDIT: A factor is not just the average stress on the track. There can be a relatively unpredictable localized stress concentration when the flexible track material goes over a sharp edge or point of a rock or piece of debris.

Materials are relevant to this discussion. If a track has flexible rubber but a giant leg is made from steel, that is a difference. The GFFA might have even much stronger materials equivalent to steel, possibly without having the same degree of advancement in their flexible materials suitable for tracks. Admittedly, the materials situation with the GFFA seems unknown, so the preceding is just speculation. But it is a possibility.

[nightmare]

I'm asking why even BOTHER with the AT-AT when an equal mass of A6s is probably going to be superior in most situations?

A statement yet to be proven.

You'd need eight AT-ATs--which seem analogous to APCs--to carry more troops than one Juggernaut, and they'd take up a hell of a lot more space in your cargo holds.

Factually incorrect; walkers fold legs for transportation.

And they may be wheels, but they are HUGE wheels. I'd say a massive vehicle that always has to keep three legs on the ground and has limited flexiblity and range of movement is an exceedingly poor choice for broken terrain.

Unsupported assaumption. Nevermind that wheels, while considerably faster, simply can't traverse as extreme terrain as legs would. This is why several space lander concepts are designed with legs, which are also superior to tracks in that regard. Now, this may not be an argument for AT-ATs, since indicies suggest that they are very heavy, which would limit their terrain capability severely. Wheels are only a little better in weight distribution, though, and one should note that the battle of Hoth proves that they don't have to hit the ground with a hard shock.

One would think that the engineering problems that have been solved with the AT-AT are far tougher than the issue of getting a tank the size of an office building tough enough to just run over everything in its way that isn't a significant fraction of its own height.

Line of sight.

There's not much an AT-AT can do against heavy air support aside from evacuate, whereas at least a Jug can at least fire in all directions and make a run for cover.

You seem to be under the misconcept that a jack-of-all-trades vehicle is a good thing. AT-AAs would be deployed for air cover; that's not supposed to be a task for AT-ATs, nor should it be. Specialization beats generalization in effectiveness. Howeer, one could also note that AT-AT anti-air fire control was improved after Hoth (Ref: SWTCC Blizzard units), or that some of them even had a top laser tower added for air cover.

One proton torpedo or a few shots from starfighter-grade laser weaponry are confirmed kills against AT-ATs.

Proton torpedoes are 1 for 1. That is to say, while one novel has X-Wings destroying AT-ATs with PTs, another one makes it an uncertain issue. Not ever have I noticed lasers being effective, so I'd like a source on that one; it would help my research.

Proton torpedoes are very small. The Hailfire carries a crapload of larger missiles that are confirmed one-shot kills on AT-TE.

Which, you may notice, aren't nearly as strong. AT-ATs took anti-armor artillery fire [edit: without] a flinch.

AT-ATs cannot turn worth shit and have a large, vulnerable fuel tank right underneath their legs (the explosion of this tank caused one to physically flip over in Isard's Revenge). Once their armor is pierced, AT-ATs tend to explode violently (ESB), even if someone throws a grenade in it.

You are quite simply wrong assuming that AT-ATs have poor turning ability. The movie makes it clear that this isn't the case when you take a look at the one destroying a snowspeeder. The rest of your examples are equally valid for any vehicle, including a Juggernaut.

I'd say that they are extremely vulnerable to Hailfires.

Without some actual proof, you can't simply assert that.

It is clear that AT-ATs are in trouble if the enemy is actually willing to throw fast, maneverable vehicles with antivehicle missiles at them.

This statement does not apply to Juggernauts, or in fact any other ground vehicle because?

[Stark]

Actually, I'm interested in the A6s capacity of 2 companies. It's larger than an AT-AT, but it must have much higher proportion of it's internal space devoted to troops. Maybe it doesn't carry the mix of light vehicles etc, or maybe (get this) the 40-man AT-AT number is rubbish.

I'm not certain the wheels will be able to handle broken terrain: they have less ground pressure (we can assume), but who knows what kind of incline or obstacle they can handle.

I also think it's odd that Anguirus appears to deliberately ignore than the AT-ATs were escorted. They're not a jack-of-all-trades: they're a powerful artillery platform and heavily armoured transport. Escort, vehicle and AA combat are handled by other units... not that you can use fighters under a shield with any degree of maneuverability anyway. They're slow but unstoppable: the rebel artillery would have simply shot Juggernaut wheels away, even if the wheels could handle the terrain (the 'ridge' they crossed) anyway.

[VT-16]

How exactly were they struggling in the snow?
They kept a steady pace and achieved total victory for their mission objective.

The only time they're seen is at the landing zone. "Struggling" might be my interpretation of it, though:

http://images.wikia.com/starwars/images ... n_Hoth.jpg

[Anguirus]

A statement yet to be proven.

They can't be tripped, they can have heavier armor and weapons, and they have greater capacity. I can't prove the statement except to point out, as I already have, the many vulnerabilities of the AT-AT design that no Juggernaut shares. Moreover, we've never seen them take a shot from anything heavier than an Atgar P-Tower, which is generally considered (EGWT) to be obsolete rubbish, and regardless is very small compared to other Star Wars heavy weapons we've seen.

Factually incorrect; walkers fold legs for transportation.

I know this. EIGHT walkers still takes up more space than one A6.

Nevermind that wheels, while considerably faster, simply can't traverse as extreme terrain as legs would.

This makes perfect sense for small walkers, but the AT-AT has to keep three legs on the ground, because it's huge, and has very little choice in where to put its leg down for the next stride. Its flexibility beyond what we could do with modern technology, but still very limited.

You seem to be under the misconcept that a jack-of-all-trades vehicle is a good thing. AT-AAs would be deployed for air cover; that's not supposed to be a task for AT-ATs, nor should it be. Specialization beats generalization in effectiveness. Howeer, one could also note that AT-AT anti-air fire control was improved after Hoth (Ref: SWTCC Blizzard units), or that some of them even had a top laser tower added for air cover.

All good points. However, what we see in the films is AT-ATs outpacing any support units, aside from one AT-ST.

On Hoth, this was clearly the thing to do, since the AT-ATs were armed and armored so heavily that the Rebels couldn't stop them. However, if you need troop transports, the Empire has other craft. If you need high-LOS artillery to hang back and pound Rebels, the Empire has other craft. The only thing the AT-AT seems to do is combine decent armor, a few squads of troops, and medium artillery (what fits under its *chin*) into one package. In standard battle conditions, why is this combination of roles into one vehicle effective?

That is to say, while one novel has X-Wings destroying AT-ATs with PTs, another one makes it an uncertain issue. Not ever have I noticed lasers being effective, so I'd like a source on that one; it would help my research.

Which novel makes it uncertain? Also, I gave you a source on X-wing filleting AT-ATs--Isard's Revenge.

Which, you may notice, aren't nearly as strong. AT-ATs took anti-armor artillery fire [edit: without] a flinch.

The only artillery used on Hoth were P-Towers (which suck) and misused antipersonnel turrets.

Dark Empire shows us that one could have literally yanked a turret off the Falcon, stuck it in the ground, hooked up a decent power generator, and just blasted AT-ATs until they blasted you.

The Rebels were fighting a delaying action with pitiful resources. I'm not sure how that escaped you. Any CIS or Republic ground force in the prequels is far and away better equipped. I'm sure decent artillery pieces were packed up on the transports, leaving small crappy ones behind, because even if Blizzard Force had been massacred, Death Squadron still had control of the system and could have sent more waves of attackers.

You are quite simply wrong assuming that AT-ATs have poor turning ability. The movie makes it clear that this isn't the case when you take a look at the one destroying a snowspeeder. The rest of your examples are equally valid for any vehicle, including a Juggernaut.

I mentioned the ESB "lean." I'll rewatch it when I get the chance, but from memory, it wasn't much of a turn where the legs were concerned. It can turn, but it certainly couldn't execute a quick 180 if the Rebels had attacked from behind. They would be totally dependent on AT-ST support and whatever armor they had in that eventuality.

If you can point out where the exposed fuel tank and the Explodo-Neck are on the Juggernaut design, or produce an example of someone blowing the front half off with a grenade, then I will happily concede this line of argument.

Without some actual proof, you can't simply assert that.

I'm sorry, if your idea of proof is for me to produce a Hailfire blasting an AT-AT to scrap, then we both know I can't do that. I've produced evidence, however, of smaller missiles and medium energy weapons doing so. It's also perfectly clear that Hailfires can out maneuver AT-ATs effortlessly, and since AT-ATs have no all-around weapons coverage...

I suppose you want me to find a "transitional form" between fish and tetrapod for my next trick.

This statement does not apply to Juggernauts, or in fact any other ground vehicle because?

Jugs have no vulnerable areas, all-around weapons coverage, greater speed, and since they don't have to be lifted off the ground by legs they can mount far heavier weapons and armor. I'm sure a Hailfire would stil be a threat to a Juggernaut, but if it rolls around to attack from behind the Jug can simply shoot the unarmored thing.

They're slow but unstoppable: the rebel artillery would have simply shot Juggernaut wheels away, even if the wheels could handle the terrain (the 'ridge' they crossed) anyway.

Oh, I'd LOVE to see support for that.