Defending the AT-ST

[Jedi Master Spock]

Even so, it still must turn it's entire head in order to shoot. Turret based tanks and armored vehicles are easily superior at anti-infantry combat, especially if they are equiped with auto-cannons or machine guns. A combat group with RPGs will find an AT-ST a much easily target to fight against.

It may look like a fixed firing arc that requires the entire head to rotate... but then, so does this. We may assume that the guns have limited traverse independent of the head - anything short would make any aiming impossible.

The head of the AT-ST does not traverse at a noticably slower rate than most tank turrets, as a matter of fact. 20 degrees a second is not unusually slow, and 36 degrees a second is something to write home about for a traditional MBT.

RPGs can be guided though. Perhaps it won't be a piece of cake, but still much easier to take out compared to real-world tanks and armored vehicles.

RPGs can be guided, sure - and some of the better anti-tank weapons, like the Carl Gustav 84mm I recommended using, have pretty good accuracy - but the simple fact is that a harder target to hit is a harder target to hit.

There are three steps in waxing an armored vehicle:

• Spot it.
• Hit it.
• Penetrate the armor.

For the AT-ST, step 1 is easier, step 2 is harder, step 3 is about the same.

This is something that comes up very often at SB.com or SDN, whenever there's a discussion between mecha and tanks. The ultimate conclusions are these:

1) Wheeled vehicles are vastly more stable.

Some of this depends on where you put the center of gravity, but generally yes.

In the case of the AT-ST, with a hollow short box perched on top of relatively massive legs, the center of gravity is not as badly placed as with some mecha. Overall, the AT-ST does have some stability issues, but that doesn't come into play in most situations - tripwires, flying bolas, and large massive objects trying to hit you are pretty rare.

That said, stability is mostly a software issue. Bipedal creatures demonstrate quite a bit of practical stability while maneuvering tactically.

2) Wheeled vehicles have vastly less stress on the locomotive machinery (more reliable, less expensive, etc.)

We're mostly comparing these with tracked vehicles, incidentally.

Tracked vehicles are notoriously high maintainence, thanks to the large number of moving pieces in the treads. While the ankle, knee, and hip joints must bear up under high stress with a walker, it's safe to assume that the materials are fine if you're actually using them.

Joints are generally fine - it's not a maintainence problem for construction equipment with various kinds of "joints" - they just have to be engineered more. This costs mass, not maintainence parts.

3) Wheels vehicles are vastly more efficient. This can be proven by analyzing the thermodynamic cycles of both forms of locomotion.

They are more efficient. They also can't handle as rough terrain, and for the case of the AT-ST, energy efficiency for its movement isn't a big problem - most fighting vehicles prioritize power and handling over efficiency.

4) Wheeled vehicles have much lower profiles.

This is the big one. Granted - you can build a low-set walker, but that's not what people usually think of

5) Wheeled vehicles are vastly more simple to design and construct.

Not that big an issue.

There may be some other issues that I've forgot, but the conclusion is clear: Given a similar level of technology, a wheeled or track vehicle will always be vastly superior than a walking vehicle, virtually without exception.

In some ways. You missed one of the biggest ones: Armoring. In order to efficiently distribute armor, you want a highly compact vehicle. A box is very efficient for volume to surface area, and if most of your attacks come in the same plane, a flat box is most efficient for sloping armor.

There are some advantages to some specific walking vehicles - presumably there have to be, for use to see them in widespread use - which generally includes better terrain-handling capabilities. Feet can carry you where wheels can't.

Not even close! A Bradley's anti-tank missiles are good for 3.75km, and are vastly more powerful than any RPG. Source. Another source.

I mentioned the Bradley's anti-tank missiles. The TOW missiles are the Bradley's chance against the AT-ST - and it is a pretty good weapon. The only problem, tactically speaking, is that the Bradley can't fire them off on the move, or on the spur of the moment; it has to deploy its collapsable missile launcher while stationary.

Your numbers for the 30mm Avenger are at very long ranges (500m and 1000m). At short ranges (<300m) the 25mm autocannon will be very dangerous.

Only against the sides and rear is the 25mm Bushmaster likely to penetrate. The figures I cited for the 30mm Avenger were only examples of how the front plate armor can actually stand up to 30mm rounds - bullets slow a lot in the air. The real derivation of what the AT-ST can stand up to I did using Nathan Okun's programs.

And yes, the Bushmaster is not useless. But...

As with against another Bradley, the 25mm Bushmaster can be expected to be insufficient to penetrate the frontal armor. As I mentioned, the frontal armor is probably around 2-3 times as good as the side armor. The likelihood of being able to penetrate the faceplate at any angle, or cause damage to the legs, is roughly on the same order of probability as the chance that I've underestimated the armor enough for the side and rear armor to stand up to the 25mm gun at any range and angle.

And the probability that the Bradley's armor can shed a megajoule-range blaster bolt is pretty much nil. If it comes to a gunfight - if the TOW missiles are shot down by some chance, or miss, the Bradley is in trouble, and the front side is almost certainly what it's going to be facing if it can't get a missile kill.

Now, there are other light vehicles that do mount weapons with the power to one-hit-kill an AT-ST from any angle, which can be fired on the move and have more than two rounds of ammunition. (The much-talked-about BMP-3 comes to mind, for example.)

That's another myth of walking vehicles. They can't reach more types of terrain! Any heavily forested or very rugged areas are just as impassible for a wheeled vehicle as it is for a walking vehicle. Where a wheeled vehicle can get stuck, a walking one can trip or slip. Plus it doesn't let you magically get pass tight spaces where you can't fit in the first place, or climb up a dangerously steep hill since it is your weight that keeps you from climbing it, not the wheels. In fact, since the wheels have so much more grip surfaces, you may be worse off going with legs.

Incorrect. The rough terrain problem is why we actually see legged logging robots under development - and the fact that an AT-ST is tall and narrow is what lets it slip through the trees. A Bradley has a 3.1x6.9m footprint; an AT-ST is 3.2x3.9m at the most; the bulkiest "part" can be raised or lowered a bit, and the widest axis (the hips) can be shifted somewhat diagonal to squeeze through. The AT-ST also actually has more grip surface than most wheeled vehicles its mass.

Incidentally, the gripping surface argument does not apply to wheeled vehicles in general or in this case in particular. 10 psi (estimated pressure of a standing AT-ST) is not typical tire surface pressure - that's about as low as you're supposed to let your tire pressure go off-roading in extreme conditions.

A walking vehicle can step over barriers and holes that a tracked vehicle cannot move over with impunity. It's a simple physical fact - a runner can go where a cyclist can't without dismounting and picking up the bike - and the cyclist can't carry the bike everywhere.

This is to say nothing of the problems the cyclist runs into with shocks and ramps. A foot is planted stationary on the ground in a discrete location, while a wheel necessarily goes over everything - a small hump will send you for an uncontrolled bounce into the air if you're on wheels, but doesn't if you're on foot.

And then there are traps. We've seen how walkers can succumb to traps - but if you're counting on a walker hitting a pressure plate to set off a mine, don't.

Like I've mentioned, virtually none of these advantages are true. The height advantage is useless since no decent infantry is going to stand wide open just at the edge of your reach just to get shot at. They're be hiding, and likely never engage you without anti-tank weapontry, which are dirtcheap nowadays. It's only meaningful advantage is its range, until it actually runs into a meaningful fight at which point it's fucked.

You haven't even touched the most important advantage... which is logistic. If I'm using AT-STs instead of, say, Bradleys, I don't have to refuel them every 300 miles. Land armies of the modern age are limited by their logistics trains... which ultimately are limited by the access to and transport of fuel.

Or the second most important advantage... which is the raw firepower offered by the AT-ST's megajoule range blasters, which have something like 10-20 times the rate of fire of most MBT guns. That sort of destructive direct-fire potential is impressive to modern eyes.

Now, re: the height: Hiding is much harder if you have to do it against ground level and 8 meter level. Lots of otherwise perfectly good hiding spots are all too visible from two floors up. That's the problem of height - not having a larger global horizon, but being able to see over other things and see things more clearly. If you're hiding belly-down behind light cover, the AT-ST is going to be able to spot your head from three times the range that the Bradley will. Sniper hiding up in a tree, relying on the fact that many people don't think to look up from the ground? Oops, that's eye level.

And think about anti-tank weapons for a minute. Relative to other infantry arms, they're big, heavy, expensive, carry few reloads, etc. They may be small, convenient, and cheap compared to - say - tanks, but they clearly haven't made the armored vehicle obsolete yet, and it would be very unusual to give one to every soldier in lieu of, say, an assault rifle.

[AnonymousRedShirtEnsign]

JMS, for your AT-ST speed, 15-30 mph is what we've seen, so yes in the open it can out run a human, but probably not in a forest.

Bipedal movement does have it's benefits, but it requires flexibility and should include good lateral movement, two things that the AT-ST lacks. So if it had some better (but more high maintenance) hip joints then it would be better for off road, and more agile.

I find the notion that the AT-ST is good at spotting hiding infantry to be rather amusing. It has two little viewports, with "eyelids" that prevent looking directly ahead. This indicates that the AT-ST is mainly an anti-infantry vehicle. But its armaments, while not bad as anti-infantry weapons, leave much to be desired, especially in weapon arc and rate of fire. It doesn't appear to have a sensor suite since it the Ewok "artillery" isn't delt with until used (and it doesn't have anything to do with not being a threat since they do destroy it once aware of it). The battle of Endor shows us numerous examples of AT-STs being oblivious to enemy infantry everywhere except directly in front of them.

As for horse power, the AT-ST leg is slowed down be dragging a dozen Ewoks so I doubt it's towing capacity is very good.

While it isn't feasible to equip every soldier with anti-tank weaponry, have one or two soldiers per squad isn't unrealistic.

[Jedi Master Spock]

I find the notion that the AT-ST is good at spotting hiding infantry to be rather amusing. It has two little viewports, with "eyelids" that prevent looking directly ahead. This indicates that the AT-ST is mainly an anti-infantry vehicle. But its armaments, while not bad as anti-infantry weapons, leave much to be desired, especially in weapon arc and rate of fire. It doesn't appear to have a sensor suite since it the Ewok "artillery" isn't delt with until used (and it doesn't have anything to do with not being a threat since they do destroy it once aware of it). The battle of Endor shows us numerous examples of AT-STs being oblivious to enemy infantry everywhere except directly in front of them.

It would be oh-so-nice (and oh-so-technically feasible) for the AT-ST to have at least tiny external cameras, or gun cameras, even if they seem not to be very aware of things. Granted, visibility is often a problem for armored vehicles, but you're dead right that the AT-ST jocks in ROTJ don't display very good awareness of what's around them.

My best guess is that AT-ST pilots, like old tank commanders, are supposed to be popped out looking around out the top hatch when there's not any shooting going on, but that really is a vulnerable position to be in.

As for horse power, the AT-ST leg is slowed down be dragging a dozen Ewoks so I doubt it's towing capacity is very good.

Hm. Perhaps not.

While it isn't feasible to equip every soldier with anti-tank weaponry, have one or two soldiers per squad isn't unrealistic.

1-2 per squad is about right if you're expecting trouble. I think it's typically one, with another one carrying extra ammunition for the anti-tank weapon, if you're expecting trouble on treads.

[AnonymousRedShirtEnsign]

Popping your head out and looking around for trouble is a lot more effective when you are two meters up and the tank slopes away so you don't really have a big blind spot. On an AT-ST you would rely on ground troops around your vehicle, or have to climb out of the vehicle and look down over the edge which leaves you even more vulnerable. With out a good sense of what goes on around the vehicle it is easy for an enemy to run up and put an explosive device on an ankle joint.

[2046]

In fairness, I'd imagine AT-ST threat detection sensors don't get tripped by a frickin' wooden catapult that flings rocks. Maybe IR sensors could've detected a selection of targets over thataway, but then there were so many to choose from. :)

[Nonamer]

It may look like a fixed firing arc that requires the entire head to rotate... but then, so does this. We may assume that the guns have limited traverse independent of the head - anything short would make any aiming impossible.

The head of the AT-ST does not traverse at a noticably slower rate than most tank turrets, as a matter of fact. 20 degrees a second is not unusually slow, and 36 degrees a second is something to write home about for a traditional MBT.

It'll be rather difficult to control while moving and firing and the same time. An easy task for modern MBT and IFV but I doubt it would be the case for this thing, among other problems with this setup, like reliability, G-forces on crew, etc.

RPGs can be guided, sure - and some of the better anti-tank weapons, like the Carl Gustav 84mm I recommended using, have pretty good accuracy - but the simple fact is that a harder target to hit is a harder target to hit.

There are three steps in waxing an armored vehicle:

• Spot it.
• Hit it.
• Penetrate the armor.

For the AT-ST, step 1 is easier, step 2 is harder, step 3 is about the same.

And why is number 2 so hard? You do realize it has a huge profile and it doesn't have anything near the movement of a human being, nor would it matter. A RPG will reach you in a fraction of a second at close range. Once it is in the shooter's sight and range, it's deadmeat. Perhaps at longer ranges it'll be less effectively, but you'd be very easy to ambush given how big a target you are.

This is something that comes up very often at SB.com or SDN, whenever there's a discussion between mecha and tanks. The ultimate conclusions are these:

1) Wheeled vehicles are vastly more stable.

Some of this depends on where you put the center of gravity, but generally yes.

You pretty much need go bike vs. centipede before this ceases to be true though.

In the case of the AT-ST, with a hollow short box perched on top of relatively massive legs, the center of gravity is not as badly placed as with some mecha. Overall, the AT-ST does have some stability issues, but that doesn't come into play in most situations - tripwires, flying bolas, and large massive objects trying to hit you are pretty rare.

That said, stability is mostly a software issue. Bipedal creatures demonstrate quite a bit of practical stability while maneuvering tactically.

The fact that you need so much work to get the AT-ST even remotely stable as a wheeled vehicle is a testament to its instability. I much rather prefer a low profile tank or IFV that virtually guarantees stability, regardless of whether the system is broke or not. An AT-ST or any mecha is totally dependent on whatever stability mechanism it uses to keep it standing. If it breaks, you're dead. This is true in the general case, not just the AT-ST.

2) Wheeled vehicles have vastly less stress on the locomotive machinery (more reliable, less expensive, etc.)

We're mostly comparing these with tracked vehicles, incidentally.

Tracked vehicles are notoriously high maintainence, thanks to the large number of moving pieces in the treads. While the ankle, knee, and hip joints must bear up under high stress with a walker, it's safe to assume that the materials are fine if you're actually using them.

Joints are generally fine - it's not a maintainence problem for construction equipment with various kinds of "joints" - they just have to be engineered more. This costs mass, not maintainence parts.

Of course, if you had a magically walking vehicle you can say that. You can also say that given the same level of engineering and technology you can build a vastly superior track or wheeled vehicle. And a walking vehicle has far more move parts than you're claiming. It must support every possible movement needed for balance, side to side and forwards and backwards movement. This is a pretty complicated piece of machinery and suffers enormous stresses, and in real life maintainance will be even higher than a track vehicle. In the generalized case of tanks vs. mecha, it's a vastly inferior design.

3) Wheels vehicles are vastly more efficient. This can be proven by analyzing the thermodynamic cycles of both forms of locomotion.

They are more efficient. They also can't handle as rough terrain, and for the case of the AT-ST, energy efficiency for its movement isn't a big problem - most fighting vehicles prioritize power and handling over efficiency.

It's not at all better on rough terrain, which I'll to later.

4) Wheeled vehicles have much lower profiles.

This is the big one. Granted - you can build a low-set walker, but that's not what people usually think of

True though, but it will be much slower and put even more stress on itself. The legs need to be long for reasonably faster locomotion and vertically standing beneath. It's a really bad tradeoff really.

5) Wheeled vehicles are vastly more simple to design and construct.

Not that big an issue.

In the real world it would be, or any place where you have to make them in a factory instead of a magical gift.

There may be some other issues that I've forgot, but the conclusion is clear: Given a similar level of technology, a wheeled or track vehicle will always be vastly superior than a walking vehicle, virtually without exception.

In some ways. You missed one of the biggest ones: Armoring. In order to efficiently distribute armor, you want a highly compact vehicle. A box is very efficient for volume to surface area, and if most of your attacks come in the same plane, a flat box is most efficient for sloping armor.

Thanks for the tip. ;) I'm sure there's more we've missed, like ability to carry more weight.

There are some advantages to some specific walking vehicles - presumably there have to be, for use to see them in widespread use - which generally includes better terrain-handling capabilities. Feet can carry you where wheels can't.

Like I said before this is only a myth. A wheeled vehicle can reach very rough terrain if it was designed to handle it. A Humvee can reach a 60% slope and even directly run over a wall 18 inches or so high (got this from a TV show, but it's fuzzy recollection) without issue. Fording over shoulder high water and mud is also no problem. These are places a AT-ST problem can't reach without get stuck or slipping.

I mentioned the Bradley's anti-tank missiles. The TOW missiles are the Bradley's chance against the AT-ST - and it is a pretty good weapon. The only problem, tactically speaking, is that the Bradley can't fire them off on the move, or on the spur of the moment; it has to deploy its collapsable missile launcher while stationary.

With a 3.75km range, that's not a problem. Real tanks get smashed by it. There's no reason why a AT-ST going to last better with missing long-ranged weapons.

Only against the sides and rear is the 25mm Bushmaster likely to penetrate. The figures I cited for the 30mm Avenger were only examples of how the front plate armor can actually stand up to 30mm rounds - bullets slow a lot in the air. The real derivation of what the AT-ST can stand up to I did using Nathan Okun's programs.

And yes, the Bushmaster is not useless. But...

As with against another Bradley, the 25mm Bushmaster can be expected to be insufficient to penetrate the frontal armor. As I mentioned, the frontal armor is probably around 2-3 times as good as the side armor. The likelihood of being able to penetrate the faceplate at any angle, or cause damage to the legs, is roughly on the same order of probability as the chance that I've underestimated the armor enough for the side and rear armor to stand up to the 25mm gun at any range and angle.

Likewise the front of the Bradley should be similar heavily armored. The gun on the Bradley, while it's mostly an anti-infantry weapon, but it's not useless. Probably has similar if not longer range.

And the probability that the Bradley's armor can shed a megajoule-range blaster bolt is pretty much nil. If it comes to a gunfight - if the TOW missiles are shot down by some chance, or miss, the Bradley is in trouble, and the front side is almost certainly what it's going to be facing if it can't get a missile kill.

That's a nearly best case scenario. It has 6-7 missiles, and the missile launcher can be replace or fixed. Not to mention the AT-ST can break down too. Even so, the Bradley can still run away faster. It's simply not a fair fight anymore now, and still it's not really a clean winnable scenario for the AT-ST.

Now, there are other light vehicles that do mount weapons with the power to one-hit-kill an AT-ST from any angle, which can be fired on the move and have more than two rounds of ammunition. (The much-talked-about BMP-3 comes to mind, for example.)

The Bradley has 6 or 7 rounds of missiles.

Incorrect. The rough terrain problem is why we actually see legged logging robots under development - and the fact that an AT-ST is tall and narrow is what lets it slip through the trees. A Bradley has a 3.1x6.9m footprint; an AT-ST is 3.2x3.9m at the most; the bulkiest "part" can be raised or lowered a bit, and the widest axis (the hips) can be shifted somewhat diagonal to squeeze through. The AT-ST also actually has more grip surface than most wheeled vehicles its mass.

And yet we still sent a cleverly designed wheeled vehicle to Mars, over legged designs.

That founds like far too little benefit for all that work. Trees are vertical object, so it can't fit between the trees, it'll never go through. And it doesn't have more grip surface going against a tracked vehicle at all.

Incidentally, the gripping surface argument does not apply to wheeled vehicles in general or in this case in particular. 10 psi (estimated pressure of a standing AT-ST) is not typical tire surface pressure - that's about as low as you're supposed to let your tire pressure go off-roading in extreme conditions.

A walking vehicle can step over barriers and holes that a tracked vehicle cannot move over with impunity. It's a simple physical fact - a runner can go where a cyclist can't without dismounting and picking up the bike - and the cyclist can't carry the bike everywhere.

And when does this ever happen? You'll rarely see a landscape densely covered in larged obstacles that you can't around. If it was created artificially, then it's a trap or some other heavily defended region and it would be an easy place to smash a AT-ST. If you consider the places you can't really go with the AT-ST, you are at best getting a tie in terms of terrain traversal.

This is to say nothing of the problems the cyclist runs into with shocks and ramps. A foot is planted stationary on the ground in a discrete location, while a wheel necessarily goes over everything - a small hump will send you for an uncontrolled bounce into the air if you're on wheels, but doesn't if you're on foot.

Uh, every step you take will bump you up into the air. ;) With good suspension it shouldn't be a problem.

And then there are traps. We've seen how walkers can succumb to traps - but if you're counting on a walker hitting a pressure plate to set off a mine, don't.

Use more trip mines then. ;)

You haven't even touched the most important advantage... which is logistic. If I'm using AT-STs instead of, say, Bradleys, I don't have to refuel them every 300 miles. Land armies of the modern age are limited by their logistics trains... which ultimately are limited by the access to and transport of fuel.

Not very useful if it gets its ass kicked as soon as it fights. And you wouldn't send those things to the middle of nowhere without a supply-chain. You still want food, water, medicine, replacement parts, personnel, etc. I doubt removing the need for fuel and ammunition makes it the supply problem all that much better.

Or the second most important advantage... which is the raw firepower offered by the AT-ST's megajoule range blasters, which have something like 10-20 times the rate of fire of most MBT guns. That sort of destructive direct-fire potential is impressive to modern eyes.

It has way to short of a range though. A MBT is a ballistic weapon and is good for miles, and so are missiles. I guess this gets more into the problems of direct-energy weapons vs. kinetic weapons than the AT-ST vs. tank problem though.

Now, re: the height: Hiding is much harder if you have to do it against ground level and 8 meter level. Lots of otherwise perfectly good hiding spots are all too visible from two floors up. That's the problem of height - not having a larger global horizon, but being able to see over other things and see things more clearly. If you're hiding belly-down behind light cover, the AT-ST is going to be able to spot your head from three times the range that the Bradley will. Sniper hiding up in a tree, relying on the fact that many people don't think to look up from the ground? Oops, that's eye level.

That's rather unlikely. Infantry will probably hide in well-hidden location where an 8 meter height advantage is useless, especially if you knew it was 8 meters high. Tanks and IFV would never need to hid in a fight. Just target with infrared and radar and shoot. For tanks and IFV, it should be a straight up shootfest and a quick win after that.

And think about anti-tank weapons for a minute. Relative to other infantry arms, they're big, heavy, expensive, carry few reloads, etc. They may be small, convenient, and cheap compared to - say - tanks, but they clearly haven't made the armored vehicle obsolete yet, and it would be very unusual to give one to every soldier in lieu of, say, an assault rifle.

Doesn't change the fact that RPGs are very useful against tanks and IFV. During WWII shaped charges were enormously deadly, but now armor is a lot better against those things so it's been mitigated by a lot. Given the advantages and disadvantages, I much rather have a tank or IFV.

I think frankly, the problem with the AT-ST is that its a walker in the first place. Make it a tank and it would massively superior in nearly all aspects.

[Jedi Master Spock]

It'll be rather difficult to control while moving and firing and the same time. An easy task for modern MBT and IFV but I doubt it would be the case for this thing, among other problems with this setup, like reliability, G-forces on crew, etc.

Traditionally, the gunner is in the turret. Some manned turrets have much faster swivels than seen on typical tanks. Humans swivel much faster than turrets normally; it's not a problem for the AT-ST's crew in the slightest.

And why is number 2 so hard? You do realize it has a huge profile and it doesn't have anything near the movement of a human being, nor would it matter. A RPG will reach you in a fraction of a second at close range. Once it is in the shooter's sight and range, it's deadmeat. Perhaps at longer ranges it'll be less effectively, but you'd be very easy to ambush given how big a target you are.

"Huge" meaning "not all that big." And I am talking about the long ranges there.

You pretty much need go bike vs. centipede before this ceases to be true though.

Not at all. The height of the center of gravity is really the only thing that matters here.

The fact that you need so much work to get the AT-ST even remotely stable as a wheeled vehicle is a testament to its instability. I much rather prefer a low profile tank or IFV that virtually guarantees stability, regardless of whether the system is broke or not. An AT-ST or any mecha is totally dependent on whatever stability mechanism it uses to keep it standing. If it breaks, you're dead. This is true in the general case, not just the AT-ST.

Of course, if you had a magically walking vehicle you can say that. You can also say that given the same level of engineering and technology you can build a vastly superior track or wheeled vehicle. And a walking vehicle has far more move parts than you're claiming.

No, it doesn't. You have the hip joint, the knee joint, and the ankle joint - three joints, three parts to each leg. Tracks have an enormous number of pieces. In general, an AWD vehicle will have drive shafts, axles, and tires. The tires are the only thing that really need regular replacing. There's really no reason to think the AT-ST is going to be a maintainence nightmare.

It must support every possible movement needed for balance, side to side and forwards and backwards movement.

No, just the movements it makes.

This is a pretty complicated piece of machinery and suffers enormous stresses, and in real life maintainance will be even higher than a track vehicle. In the generalized case of tanks vs. mecha, it's a vastly inferior design.

Not really.

True though, but it will be much slower and put even more stress on itself. The legs need to be long for reasonably faster locomotion and vertically standing beneath. It's a really bad tradeoff really.

In the real world it would be, or any place where you have to make them in a factory instead of a magical gift.

Oh, are you saying the actual manufacture would be hopelessly complex? Not at all.

Like I said before this is only a myth. A wheeled vehicle can reach very rough terrain if it was designed to handle it. A Humvee can reach a 60% slope and even directly run over a wall 18 inches or so high (got this from a TV show, but it's fuzzy recollection) without issue. Fording over shoulder high water and mud is also no problem. These are places a AT-ST problem can't reach without get stuck or slipping.

It's not at all a myth - as I pointed out to you in no uncertain terms. I can reach a 60% slope on foot pretty easily. I can step over a wall three feet high - or step up on it. I can ford shoulder high water and go through mud and snow - and I'm not a hummer. I'm just a garden variety biped with no height advantage over the hummer. I can't do that nearly as well on roller blades or a bicycle.

An AT-ST, in spite of being much less limber, is able to step over a couple meters of wall. Or large rocks. Or shrubbery.

With a 3.75km range, that's not a problem. Real tanks get smashed by it. There's no reason why a AT-ST going to last better with missing long-ranged weapons.

The problem is that you have to basically ambush the AT-ST. If it has line of sight to you - which, if you can fire a missile at it, it can - it can shoot you up while you're sitting stationary with your launcher out.

Likewise the front of the Bradley should be similar heavily armored.

It is similarly armored, but the AT-ST's blasters pack a punch closer to the TOW missiles, so the Bradley's armor becomes a moot point.

That's a nearly best case scenario. It has 6-7 missiles, and the missile launcher can be replace or fixed. Not to mention the AT-ST can break down too. Even so, the Bradley can still run away faster. It's simply not a fair fight anymore now, and still it's not really a clean winnable scenario for the AT-ST.

You need your first missile to hit. The Bradley does not reload missiles very fast.

The Bradley has 6 or 7 rounds of missiles.

It can't just fire them off in a string - or fire them off on the move, or fire them off in a hurry.

And yet we still sent a cleverly designed wheeled vehicle to Mars, over legged designs.

And? We're still working out the bugs of legged robots. No surprise there... and in spite of the fact that we're still figuring things out, NASA's still talking about legged rovers. Because - surprise - there are places the legs-on-wheels rovers have been unable to go that they're pretty sure they could get a legged robot to go investigate.

They've moved to legs-on-wheels, of course, because that lets them handle much more than just plain wheels.

That founds like far too little benefit for all that work. Trees are vertical object, so it can't fit between the trees, it'll never go through. And it doesn't have more grip surface going against a tracked vehicle at all.

It even comes close to tracked vehicles its size. Betters many of them, actually.

The AT-ST has nice big broad feet - on the order of 1.3 square meters each. As a matter of fact, the Abrams - to pull an example out of a hat - has a surface pressure of 15 psi on its treads - again, less than a standing AT-ST, which means again that it has less gripping surface per unit mass.

Not all mecha - IMO, the AT-ST barely qualifies as "mecha" - have such a quantity of gripping surface, of course.

And when does this ever happen? You'll rarely see a landscape densely covered in larged obstacles that you can't around. If it was created artificially, then it's a trap or some other heavily defended region and it would be an easy place to smash a AT-ST. If you consider the places you can't really go with the AT-ST, you are at best getting a tie in terms of terrain traversal.

Actually, I see landscapes that you can't effectively travel through much but the roads with a wheeled vehicle. On a pretty regular basis.

Uh, every step you take will bump you up into the air. ;)

Deliberately, and in a very particular, controlled, and rhythmic manner. The bumps will go every which way when you drive over rough terrain, and a large hump at high speeds becomes a ramp inevitably.

With good suspension it shouldn't be a problem.

It can be a problem even with good suspension.

Use more trip mines then. ;)

To be sure you catch an AT-ST that way, you need to set the trip wire fairly high. Which means, in turn, that it's quite a bit more visible to, say, ground troops. And then it's also good against weaker mines that would ordinarily just immobilize a tank or truck; a mine capable of busting up treads or wheels isn't going to do much against a the solid chunk of metal that is a mecha foot.

Not very useful if it gets its ass kicked as soon as it fights. And you wouldn't send those things to the middle of nowhere without a supply-chain. You still want food, water, medicine, replacement parts, personnel, etc. I doubt removing the need for fuel and ammunition makes it the supply problem all that much better.

It makes it immensely better - especially the fuel problem. A Bradley goes through about 2/3 of a gallon of fuel per mile. If it is being operated in a mobile campaign, it's going to be needing a full load of fuel at least once per day - that's about three quarters of a ton of fuel, and then you need to spend fuel to send the fuel trucks back and forth, escort your convoys with more fighting vehicles... etc It's ugly.

If you're spending ammunition a great deal, you might go through a few hundred pounds in a bad day.

By comparison, you're only needing to ship around on the order of ten or twenty pounds a day to feed, water, medicate, and sanitize the crew. Personnel changes, spare parts, etc., are shipped much more rarely; overall, we're talking about roughly two orders of magnitude your logistics are streamlined by.

This is incredible. By the time you've spent a week in the field, you've saved enough transportation capacity and man-hours to put another whole AT-ST on the front - even considering that you could have deployed two for each Bradley in the first place.

And that's not even talking about the sort of problems that a Bradley would run into in an extended campaign on an unsettled planet.

It has way to short of a range though. A MBT is a ballistic weapon and is good for miles, and so are missiles. I guess this gets more into the problems of direct-energy weapons vs. kinetic weapons than the AT-ST vs. tank problem though.

"Short" seems to essentially mean "line of sight." Which isn't actually that short; accordingly, AT-STs are good so far as their aim is good, which is potentially equal to any other directly fired or optically sighted weapon. It's not clear what the exact physical accuracy of the blasters is from the movies, but seeing as similar designs are used on board ships, it's probably fairly mechanically precise. The guns being 6 meters off the ground or so means that in open terrain, the AT-ST can shoot for miles and miles.

Where the AT-ST misses out is picking up an enemy on radar and putting a guided missile up his tail - and really, that's not something you do so easily on the ground.

That's rather unlikely. Infantry will probably hide in well-hidden location where an 8 meter height advantage is useless, especially if you knew it was 8 meters high. Tanks and IFV would never need to hid in a fight. Just target with infrared and radar and shoot. For tanks and IFV, it should be a straight up shootfest and a quick win after that.

My point is that there are far fewer such hiding places.

You don't always have all the time in the world to set up an ambush for the AT-STs in a place of your choosing. Sure, there are problems with the AT-ST, and it could be better - but overall, it's not nearly as bad as it has been made out to be. Not by modern standards.

[AnonymousRedShirtEnsign]

Even assuming that the advantages and disadvantages of walker vs tank balance out, the AT-ST is still poorly executed. It's hip and ankle joints are not made well for side to side stability, and we never see it straif or even turn more than 10 degrees to one side or the other while walking.

As for accuracy at long range. We see it is pretty effective against targets from 10-30m away on Endor. It would probably be pretty accurate against stationary targets at a few hundred meters, but even a target moving in a strait line seems beyond Star Wars target tracking. So while it could shoot for miles and miles (assuming the blaster bold doesn't disintegrate) I wouldn't count on hitting a specific target at anything more than 300m or so.

[Mr. Oragahn]

What's the support surface of an AT-ST's foot?

[Jedi Master Spock]

What's the support surface of an AT-ST's foot?

The AT-ST blueprints you can find on SWTC give you a 710 pixel tall AT-ST at 8.13m. The feet, on the blueprints, appear to be roughly circular in their surface, 110x110 px, i.e., 1.25m across, with an area of about 1.25m^2. In practice, they seem to have been elongated slightly from the blueprints, which is why I'm saying 1.3 m^2.

Now, the highest stress item of the AT-ST has got to be the lowest part of the leg, between the second knee and the ankle. That is - on the blueprints - only 11x21 px, and seems to be about that size on images, which means it has a cross section of ~0.03 m^2 - when walking, the entire weight of the AT-ST comes down on this and then some, but this range of forces is well within the structural strength of steel for the speeds we've seen.

They also have "toes" sticking forward slightly, which Saxton has suggested are wire cutters, and which I suspect might serve more like actual toes.

[Nonamer]

Traditionally, the gunner is in the turret. Some manned turrets have much faster swivels than seen on typical tanks. Humans swivel much faster than turrets normally; it's not a problem for the AT-ST's crew in the slightest.

I don't believe it is the case for modern tanks though. Either way, it's not an efficient design to swing the entire head to shoot.

"Huge" meaning "not all that big." And I am talking about the long ranges there.

It's still far easier to spot than a tank though. While I'm not suggest it's shoot at fish in a barrel, it should be significantly easier due its larger profile.

Not at all. The height of the center of gravity is really the only thing that matters here.

Doing that really makes the walking vehicle far more expensive and slower if you make the machine so close to the ground. Like I've said, the ideal design is with the legs directly beneath the machine, and are kept long and vertical. This is exactly like most mammals and it is the most efficient design. Cars are efficient regardless of where you put the wheels. Even if you did lower the center of gravity, you still must deal with the complexity of the walking system, which if it breaks will cause the walking vehicle to be paralyzed. Not necessarily the case with a wheeled vehicle.

No, it doesn't. You have the hip joint, the knee joint, and the ankle joint - three joints, three parts to each leg. Tracks have an enormous number of pieces. In general, an AWD vehicle will have drive shafts, axles, and tires. The tires are the only thing that really need regular replacing. There's really no reason to think the AT-ST is going to be a maintainence nightmare.

But you do realize that nearly all the parts for a wheeled or track vehicle consists of rotating gears and metal disks. A walking vehicle's parts consists of very complicated mechanical parts that need to do very complicated motions. Plus some sort of muscular system capable of moving this parts where as a car or tank only needs an engine and a crankshaft. There's a big reason why we have yet to create usable walking machines in real life and lots of wheeled vehicles.

No, just the movements it makes.

That can be incredible limiting, and dangerous. It needs the whole range of motion if it ever hopes to maintain balance with effectiveness. A wheeled vehicle is basically guaranteed stability, but a walking vehicle needs constant adjustments or it'll fall to the ground.

Not really.

That's not an argument at all. The simple fact that a wheeled vehicle experiences virtually not large shocks or impacts (aka very little G-forces) to its system makes it a far less stressful vehicle. A walking vehicle however, suffers large shocks and impacts for every step it takes, and much worse if it wants to go faster.

Oh, are you saying the actual manufacture would be hopelessly complex? Not at all.

I did not say that, but in real life they are much more complicated to make. There's a reason why we don't have many walking robots produced compared to the number of wheeled vehicles produced. And it's not for a lack of trying though; Honda's Asimo took years and enormous research costs to make and it is nothing like a real human being in terms of performance.

It's not at all a myth - as I pointed out to you in no uncertain terms. I can reach a 60% slope on foot pretty easily. I can step over a wall three feet high - or step up on it. I can ford shoulder high water and go through mud and snow - and I'm not a hummer. I'm just a garden variety biped with no height advantage over the hummer. I can't do that nearly as well on roller blades or a bicycle.

That's in part bicycles and roller blades are not meant to cross rough terrain. A Humvee is meant to do just that, and it's very good at it. And you would want walk up a 60% slope if you're the size of an elephant. At that size, you'll face a large risk slipping and falling.

An AT-ST, in spite of being much less limber, is able to step over a couple meters of wall. Or large rocks. Or shrubbery.

Like I said, a car can just go around. It's very unlikely to run into a landscape where there is heavily covered in large obstacles enough such that you can't bypass it. Walls of a few meters in height are the only credible things that a walking vehicle can get around that the wheeled vehicle can't. However these are man made objects, not natural, which means very different things. Traditionally, we would just blown up the wall. And if the enemy knew that you can walk over the wall, they'd build a bigger wall. Man-made obstacles tended to change in order to keep out the undesired objects and are a poor judge of of mobility.

The problem is that you have to basically ambush the AT-ST. If it has line of sight to you - which, if you can fire a missile at it, it can - it can shoot you up while you're sitting stationary with your launcher out.

3.75km is not a "line of sight" weapon! At least not in the traditional sense. That's well beyond the range of the blasters on the AT-ST from everything we saw in the movies.

It is similarly armored, but the AT-ST's blasters pack a punch closer to the TOW missiles, so the Bradley's armor becomes a moot point.

Perhaps.

You need your first missile to hit. The Bradley does not reload missiles very fast.

The first missile should work.

It can't just fire them off in a string - or fire them off on the move, or fire them off in a hurry.

I mean that it won't run out of missiles. A Bradley will likely take out multiple AT-STs in realistic combat scenarios.

And? We're still working out the bugs of legged robots. No surprise there... and in spite of the fact that we're still figuring things out, NASA's still talking about legged rovers. Because - surprise - there are places the legs-on-wheels rovers have been unable to go that they're pretty sure they could get a legged robot to go investigate.

Major testament to the problems of the walking vehicle compared to the wheeled one. And the wheeled vehicle has impressive rough terrain traversing abilities. There was nothing on Mars that the wheeled vehicle could traverse, except for the climbs and large boulders that a walking vehicle probably couldn't reach either.

They've moved to legs-on-wheels, of course, because that lets them handle much more than just plain wheels.

No they're not. The next Mars rover is still a wheeled vehicle, and they have no plans to make a walking one with regards to further Mars exploration. And the "legs-on-wheels" are merely a complicated suspension system, I can't see how you can call it "legs" by any sense of the word.

It even comes close to tracked vehicles its size. Betters many of them, actually.

The AT-ST has nice big broad feet - on the order of 1.3 square meters each. As a matter of fact, the Abrams - to pull an example out of a hat - has a surface pressure of 15 psi on its treads - again, less than a standing AT-ST, which means again that it has less gripping surface per unit mass.

Not all mecha - IMO, the AT-ST barely qualifies as "mecha" - have such a quantity of gripping surface, of course.

An Abrams is about 3 or 4 times heavier than the AT-ST. The whole source of the AT-ST's advantages is based on the idea that it can be super light. Realistically, it's not going to have those advantages. Though we are going into the general case rather than just the question of the AT-ST's practicality, it does point out that we are giving the AT-ST a very large number of sci-fi tech and it still doesn't really compare to existing combat vehicles very well.

Actually, I see landscapes that you can't effectively travel through much but the roads with a wheeled vehicle. On a pretty regular basis.

Such as? Neither densely forested areas or swamps are traversable by either. Cliffs are another impassible obstacle. Steep hills are traversable by either if not only possible for the wheeled vehicles. Places with loose surfaces are probably not safe for either. There's very few places that I can envision that one can go and the other can't.

Uh, every step you take will bump you up into the air. ;)

Deliberately, and in a very particular, controlled, and rhythmic manner. The bumps will go every which way when you drive over rough terrain, and a large hump at high speeds becomes a ramp inevitably.

An Abrams can actually safely do jumps on ramps. They've showed it on the Discover channel. And the "rhythmic" bumps are still still bumps, which puts stress on the system for every single step. A wheeled vehicle only experiences that when it hits a bump.

It can be a problem even with good suspension.

Not nearly as bad as a walking vehicle. It's like hitting a bump with every single step. A suspension system only needs to deal with the uncommon events.

To be sure you catch an AT-ST that way, you need to set the trip wire fairly high. Which means, in turn, that it's quite a bit more visible to, say, ground troops. And then it's also good against weaker mines that would ordinarily just immobilize a tank or truck; a mine capable of busting up treads or wheels isn't going to do much against a the solid chunk of metal that is a mecha foot.

You can also bury larger mines, or proximity mines. Or use more mines. Actually saying a walking vehicle is less susceptible to mines is like playing Russian roulette since it depends on how lucky you are. You would still not immune to mines, just perhaps somewhat less likely to hit one.

It makes it immensely better - especially the fuel problem. A Bradley goes through about 2/3 of a gallon of fuel per mile. If it is being operated in a mobile campaign, it's going to be needing a full load of fuel at least once per day - that's about three quarters of a ton of fuel, and then you need to spend fuel to send the fuel trucks back and forth, escort your convoys with more fighting vehicles... etc It's ugly.

If you're spending ammunition a great deal, you might go through a few hundred pounds in a bad day.

By comparison, you're only needing to ship around on the order of ten or twenty pounds a day to feed, water, medicate, and sanitize the crew. Personnel changes, spare parts, etc., are shipped much more rarely; overall, we're talking about roughly two orders of magnitude your logistics are streamlined by.

This is incredible. By the time you've spent a week in the field, you've saved enough transportation capacity and man-hours to put another whole AT-ST on the front - even considering that you could have deployed two for each Bradley in the first place.

And that's not even talking about the sort of problems that a Bradley would run into in an extended campaign on an unsettled planet.

Wasn't this just on Earth? No matter, you will still have a need for a supply chain. Even with your AT-ST you wouldn't dare fight complete without supplies, nor would you go maverick and send AT-ST to fight behind enemy lines with poor guarantees of supplies. It's a cost benefit, not a massive advantage. In fact modern Abrams tanks intentionally went with the gas guzzling turbine engine instead of a more efficient diesel engine. Fuel can be supplied cheaply and readily, at least when it comes to the US army.

And the real measure of the usability of the AT-ST should be what happens if the fusion reactor was simply ripped out and put on a Bradley or Abrams. I think if we had cheap AT-ST lying around, we would salvage them into better combat vehicles rather than use them.

"Short" seems to essentially mean "line of sight." Which isn't actually that short; accordingly, AT-STs are good so far as their aim is good, which is potentially equal to any other directly fired or optically sighted weapon. It's not clear what the exact physical accuracy of the blasters is from the movies, but seeing as similar designs are used on board ships, it's probably fairly mechanically precise. The guns being 6 meters off the ground or so means that in open terrain, the AT-ST can shoot for miles and miles.

Where the AT-ST misses out is picking up an enemy on radar and putting a guided missile up his tail - and really, that's not something you do so easily on the ground.

The main battle cannon of a Abrams is good for about 4 km BTW. We've never seen the AT-ST have that kind of range.

My point is that there are far fewer such hiding places.

You don't always have all the time in the world to set up an ambush for the AT-STs in a place of your choosing. Sure, there are problems with the AT-ST, and it could be better - but overall, it's not nearly as bad as it has been made out to be. Not by modern standards.

Depends on what you're doing. If you're doing what we're doing in Iraq, you'll almost exclusively see infantry waiting and hiding before springing a trap on the tank or IFV. In such a case, the AT-ST is a sure loser.

[Jedi Master Spock]

I don't believe it is the case for modern tanks though. Either way, it's not an efficient design to swing the entire head to shoot.

Only a few "next gen" armored vehicles (e.g., the Puma) have moved the gunner out of the turret. By and large, it's the rule that the gunner is in the turret.

It's still far easier to spot than a tank though. While I'm not suggest it's shoot at fish in a barrel, it should be significantly easier due its larger profile.

Its target profile is actually smaller from every angle than the Bradley. See earlier numbers.

Doing that really makes the walking vehicle far more expensive and slower if you make the machine so close to the ground. Like I've said, the ideal design is with the legs directly beneath the machine, and are kept long and vertical. This is exactly like most mammals and it is the most efficient design. Cars are efficient regardless of where you put the wheels. Even if you did lower the center of gravity, you still must deal with the complexity of the walking system, which if it breaks will cause the walking vehicle to be paralyzed. Not necessarily the case with a wheeled vehicle.

The complexity of most wheeled systems is such that if any part breaks, it paralyzes the vehicles. Treads, tires, wheels, drive train, or axles.

This is actually an advantage of clever multi-legged chassis; with good piloting, it's possible to proceed at reduced ability even after losing a leg. Or two. Or three or more, if you had enough to start with.
[qoute]But you do realize that nearly all the parts for a wheeled or track vehicle consists of rotating gears and metal disks. A walking vehicle's parts consists of very complicated mechanical parts that need to do very complicated motions.[/quote]
Not so. The hip is no more sophisticated than a drive train. A joint is basically a rotating metal disc.

Look at the human leg. Mechanically speaking, it isn't all that complicated. Nor, for that matter, is the AT-ST leg. The AT-ST leg is actually quite simple - it has 4 simple rotating joints, each of could be forced into motion with what is essentially a single enclosed high torque electrical motor fed through an internal power line.

In other words, the entire mechanical system of the AT-ST's legs is less complicated than a V8 engine. A single cylinder of an internal combustion engine has more moving parts than a single AT-ST joint with an internal electrical motor - and that's not invoking the drive train, axles, wheels, or gearing.

The tricky parts are the control and power systems; we're still figuring out the best way to make robots walk, and we don't have anything resembling Star Wars' most basic commercially available fusion furnaces.

That can be incredible limiting, and dangerous. It needs the whole range of motion if it ever hopes to maintain balance with effectiveness. A wheeled vehicle is basically guaranteed stability, but a walking vehicle needs constant adjustments or it'll fall to the ground.

If your drive system fails on the battlefield, you're pretty much a mission kill regardless of whether you fall over or not.

That's not an argument at all. The simple fact that a wheeled vehicle experiences virtually not large shocks or impacts (aka very little G-forces) to its system makes it a far less stressful vehicle. A walking vehicle however, suffers large shocks and impacts for every step it takes, and much worse if it wants to go faster.

These shocks and impacts are controlled and anticipated. That makes compensating for them much easier.

I did not say that, but in real life they are much more complicated to make.

Right now, they are somewhat more complicated to make... not manufacture. This isn't a manufacturing issue, it's a design issue.

There's a reason why we don't have many walking robots produced compared to the number of wheeled vehicles produced. And it's not for a lack of trying though; Honda's Asimo took years and enormous research costs to make and it is nothing like a real human being in terms of performance.

Which is entirely research and development. In absolute costs, if someone else stole the plans and mass produced Asimo, it wouldn't cost them that much per unit.

That's in part bicycles and roller blades are not meant to cross rough terrain.

Actually... many bikes are. Mountain bikes are designed carefully for rough terrain; they still can't handle what a hiker can with the same engine power. Even the best mountain bike with a skilled mountain biker is hard pressed to cover the same terrain as an amateur hiker.

A Humvee is meant to do just that, and it's very good at it.

"Very good" for a wheeled vehicle.

And you would want walk up a 60% slope if you're the size of an elephant. At that size, you'll face a large risk slipping and falling.

Depends on how flexible (and stable) the design.

Like I said, a car can just go around. It's very unlikely to run into a landscape where there is heavily covered in large obstacles enough such that you can't bypass it.

Not as unlikely as you think, actually. If you look at some of the more rugged terrain on (say) Geonosis, Endor, etc, this isn't ground that a 6.5+m long vehicle can handle very well.

Walls of a few meters in height are the only credible things that a walking vehicle can get around that the wheeled vehicle can't.

Actually, take an example of a maze of obstacles. The fact that the wheeled vehicles are much longer means they have trouble winding around a mess of fallen boulders, or trees, etc.

However these are man made objects, not natural, which means very different things. Traditionally, we would just blown up the wall. And if the enemy knew that you can walk over the wall, they'd build a bigger wall. Man-made obstacles tended to change in order to keep out the undesired objects and are a poor judge of of mobility.

Blown up constructions often manifest themselves in terms of distributed piles of rubble, with the occasional surprise basement hole. City ruins are a fine example of the sort of environment a tall biped with legs handles better than a long flat vehicle on wheels.

3.75km is not a "line of sight" weapon! At least not in the traditional sense. That's well beyond the range of the blasters on the AT-ST from everything we saw in the movies.

I beg your pardon? It is, and that also is. Wwe've seen no limits to the AT-ST range, or any other weapons in Star Wars. We've seen blaster fire reach very far before, in fact, which suggests that blaster fire is only limited by the aim of the user and line of sight to the target.

The current TOW in use is a wire guided subsonic top-attack missile. It must be fired within line of sight of its target, and the launcher must maintain line of sight to the missile in order to guide it to the target.

Perhaps.

Not "perhaps." The AT-ST's blasters are 1.5-2.5 orders of magnitude more energetic per shot than the 30mm bullets that the Bradley's armor is intended to stop.

The first missile should work.

Unless it - or you - get hit by incoming blaster fire.

I mean that it won't run out of missiles. A Bradley will likely take out multiple AT-STs in realistic combat scenarios.

And an AT-ST can take out multiple Bradleys in realistic combat scenarios. So?

Major testament to the problems of the walking vehicle compared to the wheeled one. And the wheeled vehicle has impressive rough terrain traversing abilities. There was nothing on Mars that the wheeled vehicle could traverse, except for the climbs and large boulders that a walking vehicle probably couldn't reach either.

Which is why NASA is working on walking rovers?

No, they understand perfectly well that a walking rover can go where the wheeled ones can't.

No they're not. The next Mars rover is still a wheeled vehicle, and they have no plans to make a walking one with regards to further Mars exploration. And the "legs-on-wheels" are merely a complicated suspension system, I can't see how you can call it "legs" by any sense of the word.

The 2003 rovers have what can only be described as articulate legs with wheels attached.

An Abrams is about 3 or 4 times heavier than the AT-ST.

4-5, really. It only has around 3 times the surface area.

The whole source of the AT-ST's advantages is based on the idea that it can be super light. Realistically, it's not going to have those advantages. Though we are going into the general case rather than just the question of the AT-ST's practicality, it does point out that we are giving the AT-ST a very large number of sci-fi tech and it still doesn't really compare to existing combat vehicles very well.

Actually, my mass estimates assume that the AT-ST is pretty much a modern steel-frame vehicle, and the legs mostly solid steel. Now, true, we could give it nanotubule reinforced structural members allowing the legs to be hollow and drop it to less than ten tons.

Such as? Neither densely forested areas or swamps are traversable by either.

Most densely forested areas can be. Rocky territory can also be traversed fairly easily be legged things. Uneven ground in particular is remarkably difficult (often outright impossible) for wheeled vehicles, but easy for legged vehicles. Rubble and partly destroyed buildings provide another such environment.

Cliffs are another impassible obstacle. Steep hills are traversable by either if not only possible for the wheeled vehicles. Places with loose surfaces are probably not safe for either. There's very few places that I can envision that one can go and the other can't.

An Abrams can actually safely do jumps on ramps. They've showed it on the Discover channel. And the "rhythmic" bumps are still still bumps, which puts stress on the system for every single step. A wheeled vehicle only experiences that when it hits a bump.

Anticipation is the mother of successful compensation.

Not nearly as bad as a walking vehicle. It's like hitting a bump with every single step. A suspension system only needs to deal with the uncommon events.

Actually, bumps are everywhere off the road. Big bumps are quite common if you're driving cross-country.

You can also bury larger mines, or proximity mines. Or use more mines. Actually saying a walking vehicle is less susceptible to mines is like playing Russian roulette since it depends on how lucky you are. You would still not immune to mines, just perhaps somewhat less likely to hit one.

Somewhat less likely to hit one is a very good thing.

Wasn't this just on Earth?

Right. The further your sources are from the front, the more incredible the reduction from using fusion power and energy weapons rather than chemical combustion and shells.

No matter, you will still have a need for a supply chain. Even with your AT-ST you wouldn't dare fight complete without supplies, nor would you go maverick and send AT-ST to fight behind enemy lines with poor guarantees of supplies. It's a cost benefit, not a massive advantage. In fact modern Abrams tanks intentionally went with the gas guzzling turbine engine instead of a more efficient diesel engine. Fuel can be supplied cheaply and readily, at least when it comes to the US army.

The cost benefit is a massive advantage.

And the real measure of the usability of the AT-ST should be what happens if the fusion reactor was simply ripped out and put on a Bradley or Abrams. I think if we had cheap AT-ST lying around, we would salvage them into better combat vehicles rather than use them.

No, that's the measure of how optimized a design is. If we're going to judge the AT-ST against modern vehicles, we must judge it in absolute terms: How would it fare?

Depends on what you're doing. If you're doing what we're doing in Iraq, you'll almost exclusively see infantry waiting and hiding before springing a trap on the tank or IFV. In such a case, the AT-ST is a sure loser.

Not really. Again, the AT-ST (potentially) can spot these traps from further away, meaning (a) they have less of a chance of getting nailed and (b) more time in which to start shooting back.

[Nonamer]

Only a few "next gen" armored vehicles (e.g., the Puma) have moved the gunner out of the turret. By and large, it's the rule that the gunner is in the turret.

Then the G-forces are still less, since the gunner is in the middle whereas the driver and gunner are not. Plus only the gunner is experiencing G-forces where as the pilot of the AT-ST also experiences G-forces. It's still an inferior design any way you cut it.

Its target profile is actually smaller from every angle than the Bradley. See earlier numbers.

Then it's easier to spot if not easier to hit at least. But still a hit is going to be more damaging, since the vital parts of a AT-ST are exposed, plus you can get underside hits. Alongside the inability to fight back as well, inability for crew to escape, lack of speed, etc., it's still significantly more vulnerable than a Bradley.

The complexity of most wheeled systems is such that if any part breaks, it paralyzes the vehicles. Treads, tires, wheels, drive train, or axles.

This is completely incorrect. You can lose a tire and still drive, or at least escape. Incidentally, this is also the only exposed part of the drive system. For tracked vehicles, even these parts, the tracks, are partially protected and only a lucky hit will bring them down. The rest of the parts are well protected within the vehicle and are very unlikely to get destroyed by anything less than a serious anti-tank weapon. The AT-ST on the other hand has it all exposed and is very vulnerable to hits to its locomotion system. Even a small arm can bring down the AT-ST if it hit in the right place in the leg system.

This is actually an advantage of clever multi-legged chassis; with good piloting, it's possible to proceed at reduced ability even after losing a leg. Or two. Or three or more, if you had enough to start with.

Likewise, you can have vehicles with more 4 wheels. This is an meaningless ability.

Not so. The hip is no more sophisticated than a drive train. A joint is basically a rotating metal disc.

Look at the human leg. Mechanically speaking, it isn't all that complicated. Nor, for that matter, is the AT-ST leg. The AT-ST leg is actually quite simple - it has 4 simple rotating joints, each of could be forced into motion with what is essentially a single enclosed high torque electrical motor fed through an internal power line.

Which is a ridiculous claim. The hip of a human is a ball-joint with several muscles controlling and has to allow for a large range of motions. The knees are the only thing comparable to a rotating metal disk, expect that it has to move back and forth. The feet are where the leg system lose massively. They are a very complex multi-part joint design to survive very complex movements.

This is all forgetting the types of movements it experiences. Rotating disk do exactly one type of movement and thats it. Stresses are kept very low. A leg system do very complicated movements, and may regularly experience unexpected movements like side-to-side or diagonal stresses.

And another thing: stresses in wheel systems do not accumulate. Every stress suffered by the feet are also suffered by the knees and hips. A wheeled vehicle spreads the stress around the whole system.

In other words, the entire mechanical system of the AT-ST's legs is less complicated than a V8 engine. A single cylinder of an internal combustion engine has more moving parts than a single AT-ST joint with an internal electrical motor - and that's not invoking the drive train, axles, wheels, or gearing.

A V8 engine isn't even part of the wheel system! Replace it with a electric motor or turbine and it will still work.

The tricky parts are the control and power systems; we're still figuring out the best way to make robots walk, and we don't have anything resembling Star Wars' most basic commercially available fusion furnaces.

It's not like this is the 19th century. We could build all the necessary parts for walking machine of the level of the AT-ST but we don't because it is a terrible design, not because we don't know how.

If your drive system fails on the battlefield, you're pretty much a mission kill regardless of whether you fall over or not.

Strawman. The problem is how your drive system will break, not that it will. A leg system will rapidly break unless it can handle an enormous set of motions. Wheeled vehicles don't have this problem.

These shocks and impacts are controlled and anticipated. That makes compensating for them much easier.

And how would you do that? That's another system build on top of the leg system. This is very unlike the suspension system of a car since a suspension system is nearly independent of the ability for the car to move. Any attempt to reduce the stresses of a leg system will directly interfere with the leg system, either by adding weight or restricting what you can put on a leg system.

Right now, they are somewhat more complicated to make... not manufacture. This isn't a manufacturing issue, it's a design issue.

"Somewhat more" is still more.

Which is entirely research and development. In absolute costs, if someone else stole the plans and mass produced Asimo, it wouldn't cost them that much per unit.

http://www.forbes.com/home/2002/02/21/0221tentech.html

"Less than $1 million" is the reported cost.

Actually... many bikes are. Mountain bikes are designed carefully for rough terrain; they still can't handle what a hiker can with the same engine power. Even the best mountain bike with a skilled mountain biker is hard pressed to cover the same terrain as an amateur hiker.

A mountain bike is not really meant to handle rough terrain. It's just so that you can hit a dirt road that's not flat safely. An ATV on the other hand is not much different than a human in nearly all cases, plus it's faster.

"Very good" for a wheeled vehicle.

Depends on how flexible (and stable) the design.

Not as unlikely as you think, actually. If you look at some of the more rugged terrain on (say) Geonosis, Endor, etc, this isn't ground that a 6.5+m long vehicle can handle very well.

Geonosis is a flat desert. A wheeled vehicle would have done fine. Endor is so heavily forested such that large objects can't around well at all. Give me an ATV instead of a Humvee and it should be fine.

Actually, take an example of a maze of obstacles. The fact that the wheeled vehicles are much longer means they have trouble winding around a mess of fallen boulders, or trees, etc.

These "mess of fallen boulders or trees" are not something you want a leg vehicle to traverse either. Too high of a risk of slippage or unstable terrain.

Blown up constructions often manifest themselves in terms of distributed piles of rubble, with the occasional surprise basement hole. City ruins are a fine example of the sort of environment a tall biped with legs handles better than a long flat vehicle on wheels.

That's a pretty useless excuse. You're merely bring down a wall, not a building or a whole city.

I beg your pardon? It is, and that also is. Wwe've seen no limits to the AT-ST range, or any other weapons in Star Wars. We've seen blaster fire reach very far before, in fact, which suggests that blaster fire is only limited by the aim of the user and line of sight to the target.

The current TOW in use is a wire guided subsonic top-attack missile. It must be fired within line of sight of its target, and the launcher must maintain line of sight to the missile in order to guide it to the target.

Except it is guided. It is nearly guaranteed to hit once fired. We don't know if an AT-ST will hit at that range.

And let's suppose you're right, that an AT-ST can hit at that range: Ergo, I'll merely equip my tanks with an BVR missile, guided by radar. We already have them for aircraft, so for tanks it's not a problem other than designing and producing such a thing. Once again, the AT-ST is still useless.

Not "perhaps." The AT-ST's blasters are 1.5-2.5 orders of magnitude more energetic per shot than the 30mm bullets that the Bradley's armor is intended to stop.

I was in agreement with you.

Unless it - or you - get hit by incoming blaster fire.

Assuming it can reach that far. But a longer range missile will easily defeat it still if that is the case.

And an AT-ST can take out multiple Bradleys in realistic combat scenarios. So?

Depends on who has the longer range weapon. One of these two weapon systems can have it's range extended. The other, not.

Which is why NASA is working on walking rovers?

No, they understand perfectly well that a walking rover can go where the wheeled ones can't.

The 2003 rovers have what can only be described as articulate legs with wheels attached.

WTF? It's clearly a wheeled vehicle. It has a Rocker bogie suspension system which is nothing like a leg system. Very different from a Humvee, but still a wheeled vehicle. And they have no plans to deploy any other type of mobile vehicle for Mars exploration, except perhaps for a flying explorer. Anything else is just drawing board stuff.

4-5, really. It only has around 3 times the surface area.

Ok. But the Abram clearly wins the surface area argument since they could merely lighten the load if they wanted to.

Actually, my mass estimates assume that the AT-ST is pretty much a modern steel-frame vehicle, and the legs mostly solid steel. Now, true, we could give it nanotubule reinforced structural members allowing the legs to be hollow and drop it to less than ten tons.

You're missing the point. If the Abrams was as light as the AT-ST, it would have an even better weight-to-surface ratio.

Most densely forested areas can be. Rocky territory can also be traversed fairly easily be legged things. Uneven ground in particular is remarkably difficult (often outright impossible) for wheeled vehicles, but easy for legged vehicles. Rubble and partly destroyed buildings provide another such environment.

Wheeled vehicles can easily reach rocky terrain and densely forested areas. That's exactly what we did in Afghanistan. Forested area can be reached by small vehicles, like ATVs. Something huge, like an elephant, will have serious trouble going through the forest. That's why forest elephants are pygmy elephants and not the full sized thing. Humvees can't reach forested areas because they are too large, not that they can't go there. The same is true for the AT-ST. The only you can reach that a wheeled can't is the dense obstacle region. Perhaps a rubble pile may have this characteristic, but you would never go there with a large vehicle anyways. A Mars rover could definitely do it, since that's what it's designed for and it's pretty small.

Anticipation is the mother of successful compensation.

Again, how would you do it? You can't put a suspension system nearly independent of the locomotion system like on a car.

Actually, bumps are everywhere off the road. Big bumps are quite common if you're driving cross-country.

Not every single step still, and the bumps are rarely going to be worse than speed bumps. A walking system takes an enormous amount of stress each step, since each step puts the whole weight of the machine onto each leg every step.

Somewhat less likely to hit one is a very good thing.

You'd still be crazy to walk through a minefield. And a mine would disable a tank while destroy an AT-ST. So I guess you gain some, you lose some.

Right. The further your sources are from the front, the more incredible the reduction from using fusion power and energy weapons rather than chemical combustion and shells.

The cost benefit is a massive advantage.

Not for the US military, who intentionally choose otherwise. Perhaps you can trick some incompetent third-world nation with this, but in real fight it's a meaningless advantage.

No, that's the measure of how optimized a design is. If we're going to judge the AT-ST against modern vehicles, we must judge it in absolute terms: How would it fare?

Poorly. But if you make a tank out of it, it does well if not dominate. Hell, the fusion drive is probably producing thousands of HP to move that thing. You could build a 100mph tank, or perhaps a monster tank that's still reasonably mobile. Or a hovercraft. Making a walker is a waste of resources.

Not really. Again, the AT-ST (potentially) can spot these traps from further away, meaning (a) they have less of a chance of getting nailed and (b) more time in which to start shooting back.

You're not going to spot these traps from a mile away. They're usually buried or hidden among debris, or the guys trying to get you are easily hidden behind rumble or in buildings.

[Jedi Master Spock]

Then the G-forces are still less, since the gunner is in the middle whereas the driver and gunner are not. Plus only the gunner is experiencing G-forces where as the pilot of the AT-ST also experiences G-forces. It's still an inferior design any way you cut it.

The "G-forces," as you put it, are compeletely negligible for anything short of over five times the traverse rate of modern tanks. There's no point in even bringing them up.

Then it's easier to spot if not easier to hit at least. But still a hit is going to be more damaging, since the vital parts of a AT-ST are exposed, plus you can get underside hits. Alongside the inability to fight back as well, inability for crew to escape, lack of speed, etc., it's still significantly more vulnerable than a Bradley.

The singular most vulnerable part of an AT-ST is the cabin. The large chunks of apparently mostly-solid structural steel beneath it (the legs and support carriage) are not very vulnerable to modern weapons, although they are susceptible to being tripped, or slowed down slightly by tying a dozen squirmy Ewoks on.

This is completely incorrect. You can lose a tire and still drive, or at least escape.

For a little while, at reduced capabilities. However, if you lose the wheel - which is, I will remind you, just as exposed, and directly mechanically linked to the other systems I mentioned, you're basically fucked.

Incidentally, this is also the only exposed part of the drive system. For tracked vehicles, even these parts, the tracks, are partially protected and only a lucky hit will bring them down. The rest of the parts are well protected within the vehicle and are very unlikely to get destroyed by anything less than a serious anti-tank weapon. The AT-ST on the other hand has it all exposed and is very vulnerable to hits to its locomotion system. Even a small arm can bring down the AT-ST if it hit in the right place in the leg system.

Incorrect. For weapons fire, the leg system is quite clearly the least vulnerable part of the AT-ST.

You have to penetrate roughly 1.8" of steel on the sides, or 3.6" on the front, in order to get to the juicies inside, hitting a target with several square meters of compact and contiguous surface. The most vulnerable part of the leg assembly involves a 5" thick slab of what is almost certainly solid steel or its Star Wars equivalent. And is practically impossible to hit outside of point blank range - those legs are quite skinny.

The only way the legs are vulnerable is that they're low enough for an infantryman to slap a shaped charge on them... which would, by the way, be lethal for any light armored vehicle.

Likewise, you can have vehicles with more 4 wheels. This is an meaningless ability.

Since a four legged vehicle can stand and even manage to limp on three legs, and the AT-AT has four legs, this is relevant to the overal situation. Even the wide-legged SPHA-T can be expected to drag itself with two or three legs remaining, albeit at reduced speed, as can the Trade Federation spider droids.

Which is a ridiculous claim. The hip of a human is a ball-joint with several muscles controlling and has to allow for a large range of motions.

A ball joint attached to several different muscles is pretty simple mechanically - certainly no more complex than a single four stroke engine cylinder.

There's the joint, which is to say the base and the leg bone (2 parts), and then four different muscle groups that can affect the motion of the leg relative to the hip. It's actually possible to provide the complete range of motion of a natural ball joint and assorted muscle groups through two mechanical muscles/engines (spin and swing).

A four stroke engine cylinder (just the cylinder, mind you) has seven working parts: Two valves, a chamber, a spark plug, a piston, a connecting rod, and a crankshaft. Everything but the chamber and spark plug involve some degree of physical motion.

The knees are the only thing comparable to a rotating metal disk, expect that it has to move back and forth.

The knee's healthy usage being the same range of motion can be seen by the mechanical simplicity of a hard knee brace.

The feet are where the leg system lose massively. They are a very complex multi-part joint design to survive very complex movements.

This is all forgetting the types of movements it experiences. Rotating disk do exactly one type of movement and thats it. Stresses are kept very low. A leg system do very complicated movements, and may regularly experience unexpected movements like side-to-side or diagonal stresses.

And does the AT-ST have the same range of movement in its foot? Not really. But then, neither does a human wearing hard boots. Ever worn ski boots or a similarly "hard" boot? Or a serious pair of roller blades? Your ankle can't move for squat, but you can still walk. Even if you limit the ankle's range of motion substantially, walking is still quite practicable.

So appealing to complexity isn't going to fit.

And another thing: stresses in wheel systems do not accumulate. Every stress suffered by the feet are also suffered by the knees and hips. A wheeled vehicle spreads the stress around the whole system.

Only to the degree it has many wheels, multiple drive shafts, etc., i.e., just as a walker distributes its stress among multiple legs, and just as far as it has increased complexity.

A V8 engine isn't even part of the wheel system! Replace it with a electric motor or turbine and it will still work.

Replace it with four independently powered electric motors, one on each wheel, and you maximize your mechanical simplicity. And? The Bradley doesn't, nor does any other modern armored vehicle, and it's still - even in this ideal state - not really more complicated than the AT-ST, which simply involves a slightly greater number of such independent motors - one per articulation point rather than one per wheel.

It's not like this is the 19th century. We could build all the necessary parts for walking machine of the level of the AT-ST but we don't because it is a terrible design, not because we don't know how.

All the parts are easily manufactured, assuming (of course) that we have the necessary technological base. Manufacturing is simply not the issue. We are then agreed on that?

Strawman. The problem is how your drive system will break, not that it will. A leg system will rapidly break unless it can handle an enormous set of motions. Wheeled vehicles don't have this problem.

A leg system that rapidly breaks because it can't handle the range of motion necessary for all terrain mobility will never get deployed. That's a moot point for logistical and tactical considerations. Design issues are not a problem for a society with this much experience in mechanical walking.

And how would you do that? That's another system build on top of the leg system.

The leg itself is, in some ways, your suspension system. It's designed to jostle just fine. Now, as to avoid jarring the cockpit and guns, the suspension system is addressing the same problem in the same way as a wheeled vehicle's suspension system - only it can be designed to compensate well for particular the common periods and magnitudes of disturbance.

http://www.forbes.com/home/2002/02/21/0221tentech.html

"Less than $1 million" is the reported cost.

Which will go down a lot with mass production.

A mountain bike is not really meant to handle rough terrain.

Yes it is. Mountain bikers like to handle extreme trails - and, in fact, deal with what off-road vehicles do.

It's just so that you can hit a dirt road that's not flat safely.

No, that would be a hybrid rather than street or mountain bike. A good mountain bike is build to handle the most extreme terrain you can take on two wheels.

An ATV on the other hand is not much different than a human in nearly all cases, plus it's faster.

An ATV is faster than a mountain bike because it has more horsepower... and doesn't have that much better terrain handling than one.

Geonosis is a flat desert.

The part the big open-air battle took part on is. However, there's a lot of rocky territory as well.

A wheeled vehicle would have done fine. Endor is so heavily forested such that large objects can't around well at all. Give me an ATV instead of a Humvee and it should be fine.

Large objects can't get around well, no. But remember, you're talking Humvee.

A Humvee is a roughly five ton vehicle, and you're admitting here that it's not really up to cornering around trees on Endor. An AT-ST, which is probably around fifteen tons, is... while the ATVs you're talking about are basically a small single person vehicle.

These "mess of fallen boulders or trees" are not something you want a leg vehicle to traverse either. Too high of a risk of slippage or unstable terrain.

Actually, you can simply step where the boulders aren't. You're not stepping on them; you're stepping over them. Figure that the average distance between obstacles has to drop to around a meter to reduce the AT-ST to very slow speeds, but it only has to be five meters to severely hamper the Bradley, which is also more affected by the specific distribution of obstacles.

That's a pretty useless excuse. You're merely bring down a wall, not a building or a whole city.

If you fight in a city, things get messy. Take the fighting in Stalingrad in WWII as an example of fighting in city rubble.

Except it is guided. It is nearly guaranteed to hit once fired. We don't know if an AT-ST will hit at that range.

"We don't know," you say.

Let me put it this way. The Bradley, at 3.75km, is a target that takes up at least 2.75 minutes of arc. The AT-ST fires... oh... what, up to four shots a second overall? Something like that? Flight time is around twelve seconds.

OK, so let's imagine that you're sitting around in your chicken walker, wondering where on Earth those Earth-vehicles went, and then - panic! You have twelve seconds to smash an absolutely still 8 cm dinner plate with a forty eight round clip of high explosive bullets at 100 meters. With, presumably, whatever scope the AT-ST gunner might have available for use.

And let's suppose you're right, that an AT-ST can hit at that range: Ergo, I'll merely equip my tanks with an BVR missile, guided by radar. We already have them for aircraft, so for tanks it's not a problem other than designing and producing such a thing. Once again, the AT-ST is still useless.

Whacking armored vehicles with BVR missiles is not precisely easy. And basically, these missiles are going to be seeking from above. We're starting to talk about serious missiles here with names like "Pheonix" or "Harpoon," missiles with serious launch weights and serious price tags.

Now, at this point, we're talking top attack profiles. Modern IFVs are, since they have twice the target profile from this angle, twice as easy to hit - and not considered an economically viable target for those missiles. You're starting to invoke weapons that aren't even usually used on main battle tanks in order to deal with the AT-ST threat... and which are more effective against tracked vehicles, which have a much bigger footprint as seen from the air.

WTF? It's clearly a wheeled vehicle. It has a Rocker bogie suspension system which is nothing like a leg system. Very different from a Humvee, but still a wheeled vehicle. And they have no plans to deploy any other type of mobile vehicle for Mars exploration, except perhaps for a flying explorer. Anything else is just drawing board stuff.

Looks like wheels on legs.

Ok. But the Abram clearly wins the surface area argument since they could merely lighten the load if they wanted to.

Eheh. The Abram's tread-to-weight ratio is nothing unusual for a tracked vehicle.

That, and the Abrams has serious weight issues already. If they could lighten the load just to alleviate tread pressure, they would.

You're missing the point. If the Abrams was as light as the AT-ST, it would have an even better weight-to-surface ratio.

If the Abrams was as light, it would be smaller. Really, there's not much point in complaining about what gripping surface the AT-ST has. That sort of argument might apply to Gundams, but it's not applicable to this case.

Wheeled vehicles can easily reach rocky terrain and densely forested areas. That's exactly what we did in Afghanistan.

That's exactly why Afghanistan was such a pain for the Soviets in the 80s, and exactly why the US had to exercise air power extensively - tanks can't go up mountain goat trails.

Forested area can be reached by small vehicles, like ATVs. Something huge, like an elephant, will have serious trouble going through the forest. That's why forest elephants are pygmy elephants and not the full sized thing. Humvees can't reach forested areas because they are too large, not that they can't go there. The same is true for the AT-ST. The only you can reach that a wheeled can't is the dense obstacle region. Perhaps a rubble pile may have this characteristic, but you would never go there with a large vehicle anyways. A Mars rover could definitely do it, since that's what it's designed for and it's pretty small.

A "pygmy" elephant, i.e., forest elephant, i.e., Asian elephant, has similar horizontal dimensions as an AT-ST - and is much bigger than an ATV.

You'd still be crazy to walk through a minefield. And a mine would disable a tank while destroy an AT-ST. So I guess you gain some, you lose some.

Actually, a mine that barely severs a tread's links isn't going to hurt an AT-ST's foot. A mine that outright kills an AT-ST will also probably outright kill an IFV; the crew has a better chance of not getting caught in the explosion, although they are more likely to suffer broken bones in the fall of a dead AT-ST.

Sure, you don't choose to walk through minefields, but anti-tank mines are very much a part of total warfare, and every advantage counts.

Not for the US military, who intentionally choose otherwise. Perhaps you can trick some incompetent third-world nation with this, but in real fight it's a meaningless advantage.

Nonamer, there's plenty of argument as to why the US military chose gas over diesel for the Abrams. In general, the US military seems to have been motivated by (at best) the desire to get the maximum power out of the tank engine, and in practice, the Abrams is sharply limited on the strategic field by its short range.

Something as revolutionary as practically eliminating the fuel and ammunition logistic trains would leave any US military chief dancing in the street with joy.

Assuming they don't have petrochem or ammunition manufacturer interests in mind, of course. The high cost of war is something that even the US, with deep pockets, is quite aware of right now.

Or a hovercraft. Making a walker is a waste of resources.

Repulsorcraft are incredibly good, especially when its an "antigrav" style mobility that doesn't rely on fans. IMO, Star Wars does not make nearly enough use of this.

You're not going to spot these traps from a mile away. They're usually buried or hidden among debris, or the guys trying to get you are easily hidden behind rumble or in buildings.

No, but you'll spot them at (say) 100 yards, instead of 25.

[Nonamer]

The "G-forces," as you put it, are compeletely negligible for anything short of over five times the traverse rate of modern tanks. There's no point in even bringing them up.

You can still cause nausea. Plus you can disorient the pilot. Like I said, an inferior design no matter how you cut it.

The singular most vulnerable part of an AT-ST is the cabin. The large chunks of apparently mostly-solid structural steel beneath it (the legs and support carriage) are not very vulnerable to modern weapons, although they are susceptible to being tripped, or slowed down slightly by tying a dozen squirmy Ewoks on.

And how does that make it not susceptible to modern weaponry if stone age technology can stop it? People aren't stupid. They're not going to shoot bullets at the legs, but rather any sort of light explosive or even merely trip it. None of these problems are remotely possible with a tank. Like the rotating head design, no matter how you cut it, you're still worse off and always will be. No ifs or buts about it.

For a little while, at reduced capabilities. However, if you lose the wheel - which is, I will remind you, just as exposed, and directly mechanically linked to the other systems I mentioned, you're basically fucked.

And you have 4 of them. That's a lot of redundancy still. At the very worse case, you can still flee the scene unless you've suffered enormous damage to two or more wheels. In a walker, any damage beyond minor damage is fatal, both the the crew and the vehicle itself. Not to mention how much smaller the wheels are and thus are much smaller targets compared to the legs of a walker.

Incorrect. For weapons fire, the leg system is quite clearly the least vulnerable part of the AT-ST.

You have to penetrate roughly 1.8" of steel on the sides, or 3.6" on the front, in order to get to the juicies inside, hitting a target with several square meters of compact and contiguous surface. The most vulnerable part of the leg assembly involves a 5" thick slab of what is almost certainly solid steel or its Star Wars equivalent. And is practically impossible to hit outside of point blank range - those legs are quite skinny.

The only way the legs are vulnerable is that they're low enough for an infantryman to slap a shaped charge on them... which would, by the way, be lethal for any light armored vehicle.

What the hell are you smoking here? That leg system is how much more exposed than the wheel system of a wheeled vehicle, which is massively armored from all sides except for just a few spots? The whole vehicle is protecting the wheel system, and except for mines it is arguably the safely position you can put anything on a vehicle that's still exposed. The leg system is the exact opposite, which is massively exposed except for what scrawny armor you can put on it. The fact that you had to make the cabin, the most vital part of the AT-ST, and it have it not the most well protected part of the AT-ST is a testament to the dismal tradeoffs that had to be made in order for this to work.

This is the most ludicrous statement you've made in this discussion. Seriously, you did not think this one through at all.

Since a four legged vehicle can stand and even manage to limp on three legs, and the AT-AT has four legs, this is relevant to the overal situation. Even the wide-legged SPHA-T can be expected to drag itself with two or three legs remaining, albeit at reduced speed, as can the Trade Federation spider droids.

Like I said, all inferior to what wheels can provide.

A ball joint attached to several different muscles is pretty simple mechanically - certainly no more complex than a single four stroke engine cylinder.

There's the joint, which is to say the base and the leg bone (2 parts), and then four different muscle groups that can affect the motion of the leg relative to the hip. It's actually possible to provide the complete range of motion of a natural ball joint and assorted muscle groups through two mechanical muscles/engines (spin and swing).

A four stroke engine cylinder (just the cylinder, mind you) has seven working parts: Two valves, a chamber, a spark plug, a piston, a connecting rod, and a crankshaft. Everything but the chamber and spark plug involve some degree of physical motion.

Like I said, the engine is not part of the wheel system. And there are no ball joints in a wheeled vehicle.

And does the AT-ST have the same range of movement in its foot? Not really. But then, neither does a human wearing hard boots. Ever worn ski boots or a similarly "hard" boot? Or a serious pair of roller blades? Your ankle can't move for squat, but you can still walk. Even if you limit the ankle's range of motion substantially, walking is still quite practicable.

So appealing to complexity isn't going to fit.

Even with a shoe you still need the full motion of your foot. The shoe is just a flexible cuff and the bones of the feet themselves are necessary for motion. Without the big toe, walking is nearly impossible, and so would a limited ankle for anything outside of flat surfaces.

All this is still forgetting the fact that wheel systems have very limited ranges of motion, vastly simpler than even what you're claiming. In fact, there are only three possible movements for a wheel: Forwards, backwards, and turning. Two for a track vehicle (no turning needed). And forwards and backwards are simply opposite motions of the exact same type. The foot itself does more than this, even when wearing a shoe.

Only to the degree it has many wheels, multiple drive shafts, etc., i.e., just as a walker distributes its stress among multiple legs, and just as far as it has increased complexity.

Not quite. A wheel only puts pressure on the suspension system directly connected to it. The drive shaft, axles, etc. experience none of these stresses. In a leg, all the stresses are experienced in every part of the leg. Not to mention that it gets worse whenever you move. In 4 leg systems, running requires all legs to leave the ground and you usually land with only one leg at one point. This puts all the stress onto one leg. You won't spread the stress out until you go "centipede."

Replace it with four independently powered electric motors, one on each wheel, and you maximize your mechanical simplicity. And? The Bradley doesn't, nor does any other modern armored vehicle, and it's still - even in this ideal state - not really more complicated than the AT-ST, which simply involves a slightly greater number of such independent motors - one per articulation point rather than one per wheel.

That's because we don't have an efficient electrical storage device. The leg system is simply more complicated no matter how you cut it.

All the parts are easily manufactured, assuming (of course) that we have the necessary technological base. Manufacturing is simply not the issue. We are then agreed on that?

Other than the complex motors required to create those complex motions, yes it could be described as simple. But with those extra systems, like actually getting motion, makes it much more complicated. Plus you need to get them all working together which is another complexity on top of that.

A leg system that rapidly breaks because it can't handle the range of motion necessary for all terrain mobility will never get deployed. That's a moot point for logistical and tactical considerations. Design issues are not a problem for a society with this much experience in mechanical walking.

In real life that is not the case. I think we need two distinct threads here: one for AT-ST and one for general walking vehicles. These problems only go away if you assume there exists a magical walking vehicle that already works perfectly.

The leg itself is, in some ways, your suspension system. It's designed to jostle just fine. Now, as to avoid jarring the cockpit and guns, the suspension system is addressing the same problem in the same way as a wheeled vehicle's suspension system - only it can be designed to compensate well for particular the common periods and magnitudes of disturbance.

No, this removes damage to the cabin and reduce shaking. Still, the joints and leg structures must hold enormous weights every single step, which gets amplified the faster you move. None of these forces are experienced by a wheeled vehicle. The suspension system for the wheeled vehicle is nearly independent of the locomotion portion.

Which will go down a lot with mass production.

Considering this is a human sized robot and real cars are vastly bigger and provenly cheaper, you've got the burden of proof to convince others that this could scale down that much via mass production.

Yes it is. Mountain bikers like to handle extreme trails - and, in fact, deal with what off-road vehicles do.

No, that would be a hybrid rather than street or mountain bike. A good mountain bike is build to handle the most extreme terrain you can take on two wheels.

An ATV is faster than a mountain bike because it has more horsepower... and doesn't have that much better terrain handling than one.

Ok then, drive a mountain bike in a densely forested region and see how long the bike stays up. Hell, try an offroad motorcycle, which meets your last claim of "more horsepower." An ATV will easily crush both of them.

Seriously, I can't believe you're going to compare a 2-wheel bike with a 4-wheel ATV to make this absurd comparison.

The part the big open-air battle took part on is. However, there's a lot of rocky territory as well.

There was nothing that I saw that a wheeled vehicle couldn't reach. The only thing I saw that a wheeled vehicle can't reach are the cliffs, which neither can reach.

Large objects can't get around well, no. But remember, you're talking Humvee.

A Humvee is a roughly five ton vehicle, and you're admitting here that it's not really up to cornering around trees on Endor. An AT-ST, which is probably around fifteen tons, is... while the ATVs you're talking about are basically a small single person vehicle.

They didn't go into the dense forest regions. They stayed mostly in open areas. A Humvee could've done that too.

Actually, you can simply step where the boulders aren't. You're not stepping on them; you're stepping over them. Figure that the average distance between obstacles has to drop to around a meter to reduce the AT-ST to very slow speeds, but it only has to be five meters to severely hamper the Bradley, which is also more affected by the specific distribution of obstacles.

Again, you're going back to the densely covered obstacle region, perhaps the only place a genuine advantage exists. These places are pretty rare, and you probably won't find very boulders 2-3 meters apart but not any closer.

If you fight in a city, things get messy. Take the fighting in Stalingrad in WWII as an example of fighting in city rubble.

Yet again, it's smashing a wall, not the whole damn city. In fact you only need to smash one hole in the wall to get through it, not the whole wall.

"We don't know," you say.

Let me put it this way. The Bradley, at 3.75km, is a target that takes up at least 2.75 minutes of arc. The AT-ST fires... oh... what, up to four shots a second overall? Something like that? Flight time is around twelve seconds.

OK, so let's imagine that you're sitting around in your chicken walker, wondering where on Earth those Earth-vehicles went, and then - panic! You have twelve seconds to smash an absolutely still 8 cm dinner plate with a forty eight round clip of high explosive bullets at 100 meters. With, presumably, whatever scope the AT-ST gunner might have available for use.

Assuming of course you have the sensor package to even detect the Bradley and react in time to shoot back. You're not going to notice a speck in the distance. Realistically, either the AT-ST can reach the Bradley well ahead of time or it can't, at which point it's shoot first wins. Given what we've seen in SW, I'll bet it can't find the Bradley first.

Whacking armored vehicles with BVR missiles is not precisely easy. And basically, these missiles are going to be seeking from above. We're starting to talk about serious missiles here with names like "Pheonix" or "Harpoon," missiles with serious launch weights and serious price tags.

Now, at this point, we're talking top attack profiles. Modern IFVs are, since they have twice the target profile from this angle, twice as easy to hit - and not considered an economically viable target for those missiles. You're starting to invoke weapons that aren't even usually used on main battle tanks in order to deal with the AT-ST threat... and which are more effective against tracked vehicles, which have a much bigger footprint as seen from the air.

The hellfire is a fairly compact, Helicopter based anti-tank missile. The Maverick has much longer range at a modestly expensive price tag (as military weapons go these days).

Perhaps they are indeed too much for a MBT, but now you're pitting your unproven claims of super long range and super accurate AT-ST blasters against proven weapon systems. We don't use anything beyond light anti-tank missiles because there was never any need, but I'm sure they will once the threat is perceived.

And still, the golden test for the AT-ST is would someone rather rip them apart and salvage its weapons than actually use the AT-ST. Again, a tank with this super accurate blaster would be a better idea than the AT-ST.

Looks like wheels on legs.

Looks like a suspension system with no mentions of "legs". Unless you can find genuine and specific sources for "wheels-on-legs" claim, I'm calling your bullshit. So no forum posts or tenuous interpretations.

Eheh. The Abram's tread-to-weight ratio is nothing unusual for a tracked vehicle.

That, and the Abrams has serious weight issues already. If they could lighten the load just to alleviate tread pressure, they would.

Why is the Abrams facing serious weight problems? There's been much bigger tanks built in the past, just not found to be practical. A lighter one would be the Bradley, which is also a tracked vehicle but much less capable. I suspect that a Bradley wins the surface area to weight ratio.

If the Abrams was as light, it would be smaller. Really, there's not much point in complaining about what gripping surface the AT-ST has. That sort of argument might apply to Gundams, but it's not applicable to this case.

Or a light tank or IFV I suspect. An Abrams is just for comparison.

That's exactly why Afghanistan was such a pain for the Soviets in the 80s, and exactly why the US had to exercise air power extensively - tanks can't go up mountain goat trails.

And an AT-ST can? I doubt any heavy machinery can go up a mountain goat trail.

A "pygmy" elephant, i.e., forest elephant, i.e., Asian elephant, has similar horizontal dimensions as an AT-ST - and is much bigger than an ATV.

Or perhaps about 5 feet tall. They're very small creatures.

Actually, a mine that barely severs a tread's links isn't going to hurt an AT-ST's foot. A mine that outright kills an AT-ST will also probably outright kill an IFV; the crew has a better chance of not getting caught in the explosion, although they are more likely to suffer broken bones in the fall of a dead AT-ST.

And why is that? If the machinery can be tripped, any damage to the foot could cripple the whole thing. And steel tracks are not easily broken, so real mines need to be seriously powerful.

Sure, you don't choose to walk through minefields, but anti-tank mines are very much a part of total warfare, and every advantage counts.

You never walk through a minefield you know exists. All your doing is reducing the likelihood of get hit by one if you accidentally walk into one, and if you're surface to weight ratio claim is true, this is also not much of any improvement. Anti-personnel mines didn't stop working merely because we have feet.

Nonamer, there's plenty of argument as to why the US military chose gas over diesel for the Abrams. In general, the US military seems to have been motivated by (at best) the desire to get the maximum power out of the tank engine, and in practice, the Abrams is sharply limited on the strategic field by its short range.

Something as revolutionary as practically eliminating the fuel and ammunition logistic trains would leave any US military chief dancing in the street with joy.

Assuming they don't have petrochem or ammunition manufacturer interests in mind, of course. The high cost of war is something that even the US, with deep pockets, is quite aware of right now.

We're still doing a pretty decent job of keep our army well supplied despite this, and we've lost like only 1 tank so far in the war. It still sounds like a cost advantage purely. And once again, the real victory seems to be the fusion generator, not the AT-ST itself.

Repulsorcraft are incredibly good, especially when its an "antigrav" style mobility that doesn't rely on fans. IMO, Star Wars does not make nearly enough use of this.

That's why walking vehicles in SW suck and the whole AT-ST/AT-AT/AT-TE thing is just part of a false meme in sci-fi in general. I believe it's called a brain bug in SB.com and SDN.

No, but you'll spot them at (say) 100 yards, instead of 25.

No, they never spotted them until they actually were hit. I don't think a higher vantage point would change this.