Defending the AT-ST

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Jedi Master Spock
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Post by Jedi Master Spock » Mon Jan 22, 2007 7:54 am

Nonamer wrote:You can still cause nausea. Plus you can disorient the pilot. Like I said, an inferior design no matter how you cut it.
Can you provide any sort of documentation of experienced turret gunners, on ships or tanks, experiencing motion sickness on a statistically significant basis while on the job?
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.
Not really. The motive system is practically invulnerable compared to treads or tires.
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.
It's my experience that it's hard to go far with a flat tire. Missing the wheel entirely - a level of damage easier to reach than doing anything to the leg system with a weapon - would seem likely to pretty much stop you.
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.
Actually, the motive system of a tracked vehicle presents roughly an equally easy to hit target - for those vehicles which have an armored skirts. I can show you the calculations for that if you like.

Basically speaking, them legs are skinny and move. A dinner plate is easier to shoot at that a wiggling rope.
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.
The leg system is entirely "massively armored" by virtue of being pretty much solid steel. Calling them exposed is like calling the hull of the USS North Carolina "exposed."

The treads and wheels have to have a certain degree of exposure in order to work. The legs, however, have to be incredibly strong to work - which renders them incidentally immune to fire that would penetrate the unfortunately lightly-armored cabin.

Even a civilian backhoe version of the AT-ST would be able to resist an inordinate amount of leg damage. There is literally nothing on the legs - not even the joints - which is more vulnerable to weapons fire than the most heavily protected part of a Bradley.
Like I said, the engine is not part of the wheel system. And there are no ball joints in a wheeled vehicle.
Nor on an AT-ST.
Even with a shoe you still need the full motion of your foot.
Ask any dancer. You don't use anywhere near the full range of motion of your feet while wearing shoes. Particularly boots.
Without the big toe, walking is nearly impossible
My steel toed workboots are particularly inflexible in that area. It makes it a pain to run, but I can walk in them just fine.
and so would a limited ankle for anything outside of flat surfaces.
A fairly limited amount of flexibility is required in absolute terms.
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.
Two degrees of freedom - the same as the wheel has when it turns and spins - gives you a ball joint, actually.
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.
And the AT-ST is mechanically simpler than the Bradley no matter how you try to slice the general case.
Other than the complex motors required to create those complex motions, yes it could be described as simple.
Actually, only simple motors are required to create complex motions.
Plus you need to get them all working together which is another complexity on top of that.
A complexity of R&D, but not at all in implementation once you've had the concept of walking machines down pat for generations.
In real life that is not the case.
Which is one of the numerous reasons why we see so few walking robots in real life.
I think we need two distinct threads here: one for AT-ST and one for general walking vehicles.
Perhaps so, although I would prefer to concentrate on the AT-ST in particular here. When we generalize, I think we're losing sight of the specific picture.
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.
Only so much as it works. Which we're getting better at all the time, of course.

With that thickness of structural steel - let alone anything reinforced from that - the AT-ST's legs and joints hold up very well at the speeds we see it move. The weight is not so much an issue - this is helped by the lightness of the cabin.
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.
Hm? Just add up parts. 34 articulation points... that's 34-68 electric motors, add an on-board computer, power sources, structural materials, and a couple more gewgaws. There's nothing inherently difficult about manufacturing arms or legs; we build robot arms and legs all the time.

Now, if you're essentially having to pay robotics experts to construct each one personally, the price tag is going to be high on manufacture.
Ok then, drive a mountain bike in a densely forested region and see how long the bike stays up.
Been there, done that. It does, I will grant, take skill, particularly when it's muddy out and there's no level ground, but you're underestimating cyclists and manufacturers both severely when you say that mountain bikes aren't designed to handle difficult terrain. They are so designed, and built as close to the limits of our technological capability as a price tag of several thousand dollars per bike can support.
Hell, try an offroad motorcycle, which meets your last claim of "more horsepower." An ATV will easily crush both of them.
And will still fail to handle terrain that a hiker can cover, which is my point.
Seriously, I can't believe you're going to compare a 2-wheel bike with a 4-wheel ATV to make this absurd comparison.
That 2 wheeled bike shows very well the limits of what a human's muscular power can perform on wheels - vs the well known capability of the same human on foot.
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.
Look for lower rocky areas.

And where there are cliffs, there are - or can be soon - lots of fallen rock.
They didn't go into the dense forest regions. They stayed mostly in open areas. A Humvee could've done that too.
A humvee could have probably managed to go everywhere the AT-STs did. A Bradley, however, would be highly unlikely to. 6 meters is just too long to go around trees.
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.
They aren't nearly as rare as you think.
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.
And one wall is going to be smashed into rubble out of forever?

Bad things happen when you fight in a city. Buildings are demolished, walls are smashed, and all sorts of debris winds up everywhere.
Assuming of course you have the sensor package to even detect the Bradley and react in time to shoot back.
The Mk 1 eyeball can just about resolve that as a speck. Binoculars can make it clear.

If the AT-ST has any sort of radar package in keeping with its tech base, or passive IR sensors keyed to automatic alerts, etc - and we have to assume that the Imperials are complete idiots to not include any warnings for incoming guided missiles - then the Bradley is going to be pinpointed.

And in that twelve seconds, things are going to get hot. That's the ideal situation.
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.
The Bradley needs to see the AT-ST, stop if it's moving, set up the launcher, and then fire, and not be noticed before the AT-ST gets hit.

While the TOW missiles are a nice thing to have and give you a good chance of downing an AT-ST with a Bradley, it's not a sure thing by any means.
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).
Turning either one of those into a ground-launched missile increases the launch weight and price tag substantially to maintain the performance envelope... and again, conventional IFVs are an easier target to hit with all of these, and not all IFVs carry guided missiles.

The only problem we have here is that the Empire doesn't seem to have supplied missile launchers on their AT-STs - and if there's any modular system that would be easy to add, it's gluing a missile launcher on top of the AT-ST.
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.
We don't need anything more than light anti-tank missiles to deal with AT-STs - just as we don't need anything more than light anti-tank missiles to deal with other light armored vehicles.
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.
Actually, you'd want to pull its fusion engines and use them in everything. And try to figure out how to build them.

A tank with those same cannon would be nice. You'll find no argument from me to the effect that the AT-ST is an optimal design. Even if you stuck to the walker chassis, you could improve it substantially.
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 reasonable. So no forum posts or tenuous interpretations.
Are you looking at the same pictures I am?
Why is the Abrams facing serious weight problems?
Transport. 70 ton tanks are a pain in the tail to ship.
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.
I would bet that it doesn't. See if you can dig up the pressure on the treads - I bet it's not under 10 psi.
And an AT-ST can? I doubt any heavy machinery can go up a mountain goat trail.
Mmm. Depends on the goat trail. If it's just a problem of rocks and trees, it's likelier to be able to handle more of it.
Or perhaps about 5 feet tall. They're very small creatures.
I stand corrected - African forest elephants are about 8 feet tall. Those pygmies have yet to be actually observed by Western scientists, IIRC.
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.
Why? Because the bottom of the foot is pretty much one big solid hunk of metal. Treads, however, are basically giant flat chains, with much smaller solid hunks. It takes about an order of magnitude bigger mine to blow up an AT-ST foot rathen than just sever treads.
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.
Actually, it's an obscenely expensive job.

Like I said, it's part of the whole package.
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.
I think you'll find that the basics of the AT-ST design are quite decent for a walking vehicle. It's got a relatively low center of gravity, relatively high viewports, big broad feet.

It's not actually completely horrible (perhaps repulsorlifts are more expensive, or vulnerable to disruption, or show up on scans), and much better than not having armor support - just clearly not optimal.

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Post by Nonamer » Tue Jan 23, 2007 4:46 am

P.S.: This discussion is getting too long!
Jedi Master Spock wrote:Can you provide any sort of documentation of experienced turret gunners, on ships or tanks, experiencing motion sickness on a statistically significant basis while on the job?
I don't think there's even such a thing. All I'm saying that it's possible to either causing nausea or disorient the pilot.
Not really. The motive system is practically invulnerable compared to treads or tires.
Again, what the hell are you smoking? If the joints are weak enough to be tripped, then conventional weapons like a bomb could easily knock it out.
It's my experience that it's hard to go far with a flat tire. Missing the wheel entirely - a level of damage easier to reach than doing anything to the leg system with a weapon - would seem likely to pretty much stop you.
Cars have droved with no tires for a while in car chases, and three wheels is perfectly movable in desperation for a 2-wheel drive, and for 4x4s even 2 missing wheels is still movable, albeit problematic. And once again you're repeating the absurd belief that the AT-ST legs are somehow nearly invulnerable when everything we saw says absolutely otherwise.
Actually, the motive system of a tracked vehicle presents roughly an equally easy to hit target - for those vehicles which have an armored skirts. I can show you the calculations for that if you like.

Basically speaking, them legs are skinny and move. A dinner plate is easier to shoot at that a wiggling rope.
Exactly how is the wheel easy to hit? Especially if the vehicle is moving. It's still a tiny target much smaller than a human and moves as quickly as the vehicle does.

And you don't even go after the wheels normally. In Iraq its usually a RPG or IED, which in either case the explosion is thrown onto the whole vehicle. Wheels or tracks being small are less vulnerable than the huge overall profile of the legs.
The leg system is entirely "massively armored" by virtue of being pretty much solid steel. Calling them exposed is like calling the hull of the USS North Carolina "exposed."

The treads and wheels have to have a certain degree of exposure in order to work. The legs, however, have to be incredibly strong to work - which renders them incidentally immune to fire that would penetrate the unfortunately lightly-armored cabin.

Even a civilian backhoe version of the AT-ST would be able to resist an inordinate amount of leg damage. There is literally nothing on the legs - not even the joints - which is more vulnerable to weapons fire than the most heavily protected part of a Bradley.
Except that the joints may break from any twisting or impact on the leg. A mobility kill on a Bradley requires direct damage to the wheels or track whereas any serious damage to the leg system can be fatal. You're also not differentiating the structural support part of the leg and the armoring of the leg, and just because the support column is tough doesn't mean that it is the whole that is tough. You also don't know if structural support is even resilient to damage, since it could just be a honeycomb structure design for carrying capacity and not kinetic damage. Last, the leg needs some sort of power system to move itself. That is also a vulnerable part of the leg, and any damage to that is fatal. The engine of a tank or IFV is well protected inside the vehicle itself.
Nor on an AT-ST.
You don't know that. Even if it is, something similar to a ball joint is needed in order to maintain balance in imperfect conditions.
Ask any dancer. You don't use anywhere near the full range of motion of your feet while wearing shoes. Particularly boots.
Oh yes you do, or least pretty close. Exactly how would a ballerina dancer stand on tiptoes without mobile toes? You couldn't even get into that position first with the near full mobility of the feet.
My steel toed workboots are particularly inflexible in that area. It makes it a pain to run, but I can walk in them just fine.
I was wrong on walking, but running is nearly impossible. Your work boot still flexes acceptably, so at least it's possible. Running with wooden shoes is nearly impossible.
A fairly limited amount of flexibility is required in absolute terms.
At least we can agree with that.
Two degrees of freedom - the same as the wheel has when it turns and spins - gives you a ball joint, actually.
Not the same thing. One degree of freedom is rotation in a wheel, while the ball joint is twisting in both degrees of freedom. I don't know how to put it in more formal wording. And there are no knees or feet either. Also, in track vehicles there's no turning.
And the AT-ST is mechanically simpler than the Bradley no matter how you try to slice the general case.
You're obviously wrong here, as I've already shown.
Actually, only simple motors are required to create complex motions.
I was thinking more in terms of muscles and not motors, but even with motors you need several motors in a walking vehicle, whereas a car only needs 2 (one for movement, one for turning).
A complexity of R&D, but not at all in implementation once you've had the concept of walking machines down pat for generations.
You can't assemble a more complex object at no addition cost. Plus you need more testing and a greater likelihood of failure. Anyways, we agree on R&D being more expensive.
Which is one of the numerous reasons why we see so few walking robots in real life.
Exactly. Walking robots are simply not practical.
Perhaps so, although I would prefer to concentrate on the AT-ST in particular here. When we generalize, I think we're losing sight of the specific picture.
Agreed. If possible, we should split this into 2 threads.
Only so much as it works. Which we're getting better at all the time, of course.

With that thickness of structural steel - let alone anything reinforced from that - the AT-ST's legs and joints hold up very well at the speeds we see it move. The weight is not so much an issue - this is helped by the lightness of the cabin.
I've lost you. It's obvious that a AT-ST can support its own weight, but in real life it would be very much more difficult without making the whole thing much too light to do anything in order to reduce stress on the legs.
Hm? Just add up parts. 34 articulation points... that's 34-68 electric motors, add an on-board computer, power sources, structural materials, and a couple more gewgaws. There's nothing inherently difficult about manufacturing arms or legs; we build robot arms and legs all the time.

Now, if you're essentially having to pay robotics experts to construct each one personally, the price tag is going to be high on manufacture.
That's a lot more moving pieces than a car or tank!
Been there, done that. It does, I will grant, take skill, particularly when it's muddy out and there's no level ground, but you're underestimating cyclists and manufacturers both severely when you say that mountain bikes aren't designed to handle difficult terrain. They are so designed, and built as close to the limits of our technological capability as a price tag of several thousand dollars per bike can support.

And will still fail to handle terrain that a hiker can cover, which is my point.

That 2 wheeled bike shows very well the limits of what a human's muscular power can perform on wheels - vs the well known capability of the same human on foot.
It's a narrow analogy and a bad analogy. A bike is as simple of a transportation vehicle you can find, mountain bike or no mountain bike. It's also held up by gyroscopic forces, and is not stable. A human powered 4-wheeled bike would be better, especially on uneven surfaces or hills.
Look for lower rocky areas.

And where there are cliffs, there are - or can be soon - lots of fallen rock.
I didn't see anything that a Humvee or Bradley couldn't traverse. The cliffs don't see to have much fallen rocks, no would that be an issue since you wouldn't get near those cliffs either.
A humvee could have probably managed to go everywhere the AT-STs did. A Bradley, however, would be highly unlikely to. 6 meters is just too long to go around trees.
A Humvee is only a couple meters shorter. I don't see why not. You're not gonna go into the deepest of jungle anyways.
They aren't nearly as rare as you think.
Never saw anything like that no matter where I went in various national parks.
And one wall is going to be smashed into rubble out of forever?

Bad things happen when you fight in a city. Buildings are demolished, walls are smashed, and all sorts of debris winds up everywhere.
No reason to believe that smashing a wall turns into destroying the whole city. Nothing like that happened in either Iraq or Afghanistan. In fact, in modern warfare few places have walls in the first place, other than the kind to keep out people. Plus they all must have gates of some sort to get around.
The Mk 1 eyeball can just about resolve that as a speck. Binoculars can make it clear.
Doesn't mean your brain can notice a feature that small.
If the AT-ST has any sort of radar package in keeping with its tech base, or passive IR sensors keyed to automatic alerts, etc - and we have to assume that the Imperials are complete idiots to not include any warnings for incoming guided missiles - then the Bradley is going to be pinpointed.

And in that twelve seconds, things are going to get hot. That's the ideal situation.
Well we've never seen radar in SW at all though. Even so, you're still totally dependent on the belief that an AT-ST is super accurate, something we have no evidence of.
The Bradley needs to see the AT-ST, stop if it's moving, set up the launcher, and then fire, and not be noticed before the AT-ST gets hit.

While the TOW missiles are a nice thing to have and give you a good chance of downing an AT-ST with a Bradley, it's not a sure thing by any means.
Since we have no evidence of the AT-ST working at that range, it's a draw at best.
Turning either one of those into a ground-launched missile increases the launch weight and price tag substantially to maintain the performance envelope... and again, conventional IFVs are an easier target to hit with all of these, and not all IFVs carry guided missiles.

The only problem we have here is that the Empire doesn't seem to have supplied missile launchers on their AT-STs - and if there's any modular system that would be easy to add, it's gluing a missile launcher on top of the AT-ST.
It becomes a missile battle then. The AT-ST's larger profile and theoretically larger heat output makes it a likely loser still.
We don't need anything more than light anti-tank missiles to deal with AT-STs - just as we don't need anything more than light anti-tank missiles to deal with other light armored vehicles.
I suppose I agree.
Actually, you'd want to pull its fusion engines and use them in everything. And try to figure out how to build them.

A tank with those same cannon would be nice. You'll find no argument from me to the effect that the AT-ST is an optimal design. Even if you stuck to the walker chassis, you could improve it substantially.
Now we are in agreement here.
Are you looking at the same pictures I am?
Yes, and it distinctively says "Rocker-bogie," a type of suspension system. These look nothing like legs. They do not walk or move other than to get around obstacles and there are no sources claiming otherwise. Looks like an unconventional wheeled vehicle at best.
Transport. 70 ton tanks are a pain in the tail to ship.
Combat wise, it's not a problem.

I would bet that it doesn't. See if you can dig up the pressure on the treads - I bet it's not under 10 psi.[/quote]

Going by eyeball from pictures in the wiki article, it looks like 0.5m * 3m*2 [tracks] = 3 m^2. More than the calculated area of the AT-ST from your calcs, Albeit at 30 tons it may still be more pressure.
Mmm. Depends on the goat trail. If it's just a problem of rocks and trees, it's likelier to be able to handle more of it.
It depends on the width of the goat trail then. Then wide set legs of the AT-ST doesn't mean it can traverse a narrow trail.
I stand corrected - African forest elephants are about 8 feet tall. Those pygmies have yet to be actually observed by Western scientists, IIRC.
Still much smaller than an AT-ST or Humvee/Bradley/Abrams.
Why? Because the bottom of the foot is pretty much one big solid hunk of metal. Treads, however, are basically giant flat chains, with much smaller solid hunks. It takes about an order of magnitude bigger mine to blow up an AT-ST foot rathen than just sever treads.
Mere disruption of the leg can bring it down. In fact, going by how big IEDs are right now in Iraq (See here and here, I don't you think you've protected yourself much at all.
Actually, it's an obscenely expensive job.
Call it whatever you want, but at least the tank saves more lives than the AT-ST will.
I think you'll find that the basics of the AT-ST design are quite decent for a walking vehicle. It's got a relatively low center of gravity, relatively high viewports, big broad feet.

It's not actually completely horrible (perhaps repulsorlifts are more expensive, or vulnerable to disruption, or show up on scans), and much better than not having armor support - just clearly not optimal.
Get a tank with a periscope and wide tracks. Even better than the AT-ST. Maybe even put a rocker-bogie suspension system for good measure if you want that last bit of extra mobility.

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Post by SailorSaturn13 » Tue Jan 23, 2007 2:58 pm

Ok. First some very hard fact: HEIGHT IS CONSIDERED A DISADVANTAGE FOR A MODERN TANK. HUGE EFFORTS ARE MADE TO MAKE TANKS LOWER, not higher!
This is simply what war experience teachs, and I doubt You can really argue against this. The reasons are somewhat obscured to me, but it simply IS SO.

Why well...

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.

There are also places which are HARDER to spot when being higher. Especially thin, dark trip ropes or trap plates are harder to see from 8 m height. Or, if you are hiding UNDER a branch - easy for footman, impossible by ATST.

The main problem however is YOU are much easier to spot if you are higher, which means heavy artillery can hit
you easier.
Bipedal movement does have it's benefits

Look at the human leg. Mechanically speaking, it isn't all that complicated. Nor, for that matter, is the AT-ST leg
Sorry, but this is one of the common misconceptions. You just dont understand which gap lies between human legs and AT-ST.

Human leg has dozens of bones, hundred muscles, and over 12 degrees - and it needs ALL of this. ATST leg is simpler... at the price of extreme clumsiness. Those logs over which this second ATST tripped were no ploblem even for a Humvee, let alone for a tank.

Everything significantly less complicated than human leg will be also much less stable than even a wheel. Which is the reason it is so hard to make a d3ecent foot prothesis.

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Post by Nonamer » Tue Jan 23, 2007 5:31 pm


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Post by SailorSaturn13 » Wed Jan 24, 2007 1:41 am


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.
Which is why so many children in third world get hurt by step mines.
and the front side is almost certainly what it's going to be facing if it can't get a missile kill.
And all you need is one grenade with flame agent - shoot it in the hatch and all inside are dead. Or, for that matter, a splitter bullet - just replace standard 30 mm rounds with splitter ones.

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Post by Jedi Master Spock » Wed Jan 24, 2007 3:01 am

Nonamer wrote:P.S.: This discussion is getting too long!
Agreed. Let's try to simplify. I'll try to take the pure general points into a fresh thread and reduce as much as possible.
Not really. The motive system is practically invulnerable compared to treads or tires.
Again, what the hell are you smoking? If the joints are weak enough to be tripped, then conventional weapons like a bomb could easily knock it out.
It's my experience that it's hard to go far with a flat tire. Missing the wheel entirely - a level of damage easier to reach than doing anything to the leg system with a weapon - would seem likely to pretty much stop you.
Cars have droved with no tires for a while in car chases, and three wheels is perfectly movable in desperation for a 2-wheel drive, and for 4x4s even 2 missing wheels is still movable, albeit problematic. And once again you're repeating the absurd belief that the AT-ST legs are somehow nearly invulnerable when everything we saw says absolutely otherwise.
Actually, the motive system of a tracked vehicle presents roughly an equally easy to hit target - for those vehicles which have an armored skirts. I can show you the calculations for that if you like.

Basically speaking, them legs are skinny and move. A dinner plate is easier to shoot at that a wiggling rope.
Exactly how is the wheel easy to hit? Especially if the vehicle is moving. It's still a tiny target much smaller than a human and moves as quickly as the vehicle does.

And you don't even go after the wheels normally. In Iraq its usually a RPG or IED, which in either case the explosion is thrown onto the whole vehicle. Wheels or tracks being small are less vulnerable than the huge overall profile of the legs.
The leg system is entirely "massively armored" by virtue of being pretty much solid steel. Calling them exposed is like calling the hull of the USS North Carolina "exposed."

The treads and wheels have to have a certain degree of exposure in order to work. The legs, however, have to be incredibly strong to work - which renders them incidentally immune to fire that would penetrate the unfortunately lightly-armored cabin.

Even a civilian backhoe version of the AT-ST would be able to resist an inordinate amount of leg damage. There is literally nothing on the legs - not even the joints - which is more vulnerable to weapons fire than the most heavily protected part of a Bradley.
Except that the joints may break from any twisting or impact on the leg. A mobility kill on a Bradley requires direct damage to the wheels or track whereas any serious damage to the leg system can be fatal. You're also not differentiating the structural support part of the leg and the armoring of the leg, and just because the support column is tough doesn't mean that it is the whole that is tough. You also don't know if structural support is even resilient to damage, since it could just be a honeycomb structure design for carrying capacity and not kinetic damage. Last, the leg needs some sort of power system to move itself. That is also a vulnerable part of the leg, and any damage to that is fatal. The engine of a tank or IFV is well protected inside the vehicle itself.
OK... let's try to shrink this a bit.

First, run the surface area calculations. The legs don't actually present that much more surface area than the treads - less than the treads when you account for the skirt + treads being at least as vulnerable as the legs themselves. When you combine this with the fact that the legs are long and thin and move not only with the walker, but relative to the walker, and it's clear that you're less likely to hit the walker's legs than the tanks treads.

Second, no conventional light weapons fire (30mm or less) is going to transmit the sort of momentum necessary to torque up the joints. As you've pointed out, walking involves high-stress impacts, and it's a basically reasonable assumption to say that the narrowest support section of the AT-ST leg is as durable as solid steel from any angle, and any control or power runs can be assumed to be centrally located within the leg - i.e., basically not vulnerable to damage any more than the leg is structurally

Third, the AT-ST's legs are vulnerable to gross mechanical impact, e.g., being hit with a log. This isn't often a consideration on the modern battlefield, which rarely sees tanks ram each other.

Basically speaking, the legs aren't a significant tactical vulnerability.
Nor on an AT-ST.
You don't know that. Even if it is, something similar to a ball joint is needed in order to maintain balance in imperfect conditions.
Ask any dancer. You don't use anywhere near the full range of motion of your feet while wearing shoes. Particularly boots.
Oh yes you do, or least pretty close. Exactly how would a ballerina dancer stand on tiptoes without mobile toes? You couldn't even get into that position first with the near full mobility of the feet.
My steel toed workboots are particularly inflexible in that area. It makes it a pain to run, but I can walk in them just fine.
I was wrong on walking, but running is nearly impossible. Your work boot still flexes acceptably, so at least it's possible. Running with wooden shoes is nearly impossible.
A fairly limited amount of flexibility is required in absolute terms.
At least we can agree with that.
Two degrees of freedom - the same as the wheel has when it turns and spins - gives you a ball joint, actually.
Not the same thing. One degree of freedom is rotation in a wheel, while the ball joint is twisting in both degrees of freedom. I don't know how to put it in more formal wording. And there are no knees or feet either. Also, in track vehicles there's no turning.
And the AT-ST is mechanically simpler than the Bradley no matter how you try to slice the general case.
You're obviously wrong here, as I've already shown.
Actually, only simple motors are required to create complex motions.
I was thinking more in terms of muscles and not motors, but even with motors you need several motors in a walking vehicle, whereas a car only needs 2 (one for movement, one for turning).
OK, the mechanics of the AT-ST and walking.

Dancing. A ballerina wears very flexible shoes; a modern dancer wears none, and demonstrates a truly remarkable range of foot motion. (For that matter, an inexperienced person who is used to always wearing shoes who takes up modern dance will discover foot muscles that haven't been used.) However, this range of motion isn't necessary. Just look at someone dancing in clogs, working in steel toed boots, or awkwardly tromping along in ski boots, which allow for essentially no ankle motion. Or look at someone with a "walking" cast - which allows for absolutely no motion of the ankle. However, they can still

The degrees of freedom I'm referring to are exactly the measure of movement complexity. Now, for a typical car, with turning linked to one pair of dependent wheels, that's actually only five degrees of freedom in the motion of the wheels.

The better range of motion you have control over, the more stable you are. The AT-ST has, so far as I am able to tell, 9 powered points of articulation, including the hip-swivel. It may (should, really) have some additional freedom of motion in the lateral direction at two points. That means 9 "turning wheels" of powered motion, at most 13. A Bradley, which has 6 wheels turning its treads, has 13 including the main turret.

What does all of this mean?

One, the AT-ST isn't very mechanically complex, even in terms of its external properties. Including the enormously complex mechanical processes that go into the Bradley that the AT-ST probably sidesteps by using a fusion-electric complex

Two, the AT-ST may, because of this lack of complexity, have some issues with stability. Since the canon establishes AT-STs falling accounts for a significant percentage of AT-ST casualties, this is not a surprise, but as with above, it's not something that will be taken advantage of by fully modern opposition forces. (Unlike, say, the height of the AT-ST, which makes it a prominent target.)
I've lost you. It's obvious that a AT-ST can support its own weight, but in real life it would be very much more difficult without making the whole thing much too light to do anything in order to reduce stress on the legs.
The only thing that numbers that suggest an AT-ST would likely fall apart at speed suggest - in this case - that the AT-ST is made of something well beyond our capabilities.

However, when I run the figures on a napkin, it suggests that the AT-ST can be pretty much structurally built from steel or titanium without serious structural problems at <30 mph.
It's a narrow analogy and a bad analogy. A bike is as simple of a transportation vehicle you can find, mountain bike or no mountain bike. It's also held up by gyroscopic forces, and is not stable. A human powered 4-wheeled bike would be better, especially on uneven surfaces or hills.
Which is why we see so many human powered 4 wheeled bikes? We don't. A mountain bike is, plain and simple, the best human-powered wheeled vehicle available.

The basic tradeoff - which is already visible between different wheeled vehicles - is between efficiency (speed) and power (terrain handling).
Look for lower rocky areas.

And where there are cliffs, there are - or can be soon - lots of fallen rock.
I didn't see anything that a Humvee or Bradley couldn't traverse. The cliffs don't see to have much fallen rocks, no would that be an issue since you wouldn't get near those cliffs either.
A humvee could have probably managed to go everywhere the AT-STs did. A Bradley, however, would be highly unlikely to. 6 meters is just too long to go around trees.
A Humvee is only a couple meters shorter. I don't see why not. You're not gonna go into the deepest of jungle anyways.
They aren't nearly as rare as you think.
Never saw anything like that no matter where I went in various national parks.
And one wall is going to be smashed into rubble out of forever?

Bad things happen when you fight in a city. Buildings are demolished, walls are smashed, and all sorts of debris winds up everywhere.
No reason to believe that smashing a wall turns into destroying the whole city. Nothing like that happened in either Iraq or Afghanistan. In fact, in modern warfare few places have walls in the first place, other than the kind to keep out people. Plus they all must have gates of some sort to get around.
Actually, the 6 meter length of the Bradley is critical. The average spacing of trees within a forest is, in many cases, in the 3-4 meter range - which means that while an AT-ST can barely pass through this sort of irregular grid by turning sharply, as can a small jeep, a Bradley is likely to get frequently stuck or have to take down trees. There's nothing unusual about this; it's simply a normal forest environment.
Doesn't mean your brain can notice a feature that small.
If the AT-ST has any sort of radar package in keeping with its tech base, or passive IR sensors keyed to automatic alerts, etc - and we have to assume that the Imperials are complete idiots to not include any warnings for incoming guided missiles - then the Bradley is going to be pinpointed.
And in that twelve seconds, things are going to get hot. That's the ideal situation.
Well we've never seen radar in SW at all though. Even so, you're still totally dependent on the belief that an AT-ST is super accurate, something we have no evidence of.
The Bradley needs to see the AT-ST, stop if it's moving, set up the launcher, and then fire, and not be noticed before the AT-ST gets hit.

While the TOW missiles are a nice thing to have and give you a good chance of downing an AT-ST with a Bradley, it's not a sure thing by any means.
Since we have no evidence of the AT-ST working at that range, it's a draw at best.

It becomes a missile battle then. The AT-ST's larger profile and theoretically larger heat output makes it a likely loser still.
Actually, the advantage is to the Bradley in general for an ambush scenario. I'm not assuming it will be super accurate, but the AT-ST does have a good chance of turning the odds on an ambush, assuming the very rudimentary warning systems/sensors are in use.

A draw overall is plenty good enough to show the positive side of the AT-ST's capabilities. Now, if you use something like the BMP-3 or a main battle tank, which has the capability to fire on the move with something that can one-hit kill an AT-ST, the AT-ST's chance of victory starts to approach the inverse of its dramatically greater visibility.

If both can see each other just fine, the AT-ST's smaller target profile is going to make it harder to hit (see again the numbers). If it doesn't consume more power outside of its weapons systems (and, slightly lower mechanical efficiency aside, it's not using an inefficient internal combustion engine and is roughly half the size, that's likely), then it's going to have a smaller heat profile too.
Going by eyeball from pictures in the wiki article, it looks like 0.5m * 3m*2 [tracks] = 3 m^2. More than the calculated area of the AT-ST from your calcs, Albeit at 30 tons it may still be more pressure.
If you're right, that would be ~20 psi. Half the surface area per unit weight.
Still much smaller than an AT-ST or Humvee/Bradley/Abrams.
Shorter than an AT-ST, but not all that much longer.
Mere disruption of the leg can bring it down. In fact, going by how big IEDs are right now in Iraq (See here and here, I don't you think you've protected yourself much at all.
A big enough bomb could bowl an AT-ST over. However, at that size, it's likely to outright kill some or all of a modern IFV's crew at the same range with shrapnel.
Get a tank with a periscope and wide tracks. Even better than the AT-ST. Maybe even put a rocker-bogie suspension system for good measure if you want that last bit of extra mobility.
Ahh, but that's more vulnerable to damage and raises your profile.

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Post by Jedi Master Spock » Wed Jan 24, 2007 3:08 am

SailorSaturn13 wrote:Ok. First some very hard fact: HEIGHT IS CONSIDERED A DISADVANTAGE FOR A MODERN TANK. HUGE EFFORTS ARE MADE TO MAKE TANKS LOWER, not higher!
This is simply what war experience teachs, and I doubt You can really argue against this. The reasons are somewhat obscured to me, but it simply IS SO.

Why well...
It's all about not being spotted. Ideally, you spot the enemy and shoot him without being seen. And yes, this is something the AT-ST has a lot of trouble with.
There are also places which are HARDER to spot when being higher. Especially thin, dark trip ropes or trap plates are harder to see from 8 m height. Or, if you are hiding UNDER a branch - easy for footman, impossible by ATST.
There are a few. However, in general, your ability to see things increases at 8m tall (just as your ability to be seen increases; the two are inevitably tied together.) Take "under the branch." You're only hiding successfully underneath something when the AT-ST is right on top of you; its angle of view when approaching is much lower. By the time an AT-ST is 8m from an obstacle, it has seen it at angles from 0-45 degrees, while something 4m tall has only seen it from 0-26.5 degrees; it usually has been able to watch it for longer, too.

As a matter of fact, though, trap plates are much easier to spot from above. AT-STs should be able to see (for example) pit traps better, presuming alert pilots, because the pattern of disturbance is more visible from above.

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Post by Nonamer » Wed Jan 24, 2007 6:58 am

Jedi Master Spock wrote: OK... let's try to shrink this a bit.

First, run the surface area calculations. The legs don't actually present that much more surface area than the treads - less than the treads when you account for the skirt + treads being at least as vulnerable as the legs themselves. When you combine this with the fact that the legs are long and thin and move not only with the walker, but relative to the walker, and it's clear that you're less likely to hit the walker's legs than the tanks treads.

Second, no conventional light weapons fire (30mm or less) is going to transmit the sort of momentum necessary to torque up the joints. As you've pointed out, walking involves high-stress impacts, and it's a basically reasonable assumption to say that the narrowest support section of the AT-ST leg is as durable as solid steel from any angle, and any control or power runs can be assumed to be centrally located within the leg - i.e., basically not vulnerable to damage any more than the leg is structurally

Third, the AT-ST's legs are vulnerable to gross mechanical impact, e.g., being hit with a log. This isn't often a consideration on the modern battlefield, which rarely sees tanks ram each other.

Basically speaking, the legs aren't a significant tactical vulnerability.
I've already said this: the treads have only a tiny profile from the front or side. This is virtually impossible to hit. And the real problem are blunt force attacks for legs; a large explosion like that of an IED could easily knock them all out by putting too much much torque on the joints. A tank or Humvee is mostly insulated from such things unless the explosion is close enough to take out the whole vehicle.

You can also bet that the enemy will be creative as they have shown in Iraq, and simply use bombs that eject large objects specifically to take out the legs. Simply assuming that the enemy will use the least effective weapon is totally fallacious, and completely missing the point of "design weaknesses."
OK, the mechanics of the AT-ST and walking.

Dancing. A ballerina wears very flexible shoes; a modern dancer wears none, and demonstrates a truly remarkable range of foot motion. (For that matter, an inexperienced person who is used to always wearing shoes who takes up modern dance will discover foot muscles that haven't been used.) However, this range of motion isn't necessary. Just look at someone dancing in clogs, working in steel toed boots, or awkwardly tromping along in ski boots, which allow for essentially no ankle motion. Or look at someone with a "walking" cast - which allows for absolutely no motion of the ankle. However, they can still
You can walk apparently, but you probably can't run. You also are unlikely to good at walking over rough surfaces with clogs or walking casts anymore. Work boots don't count because they have a flex point near the toes.
The degrees of freedom I'm referring to are exactly the measure of movement complexity. Now, for a typical car, with turning linked to one pair of dependent wheels, that's actually only five degrees of freedom in the motion of the wheels.

The better range of motion you have control over, the more stable you are. The AT-ST has, so far as I am able to tell, 9 powered points of articulation, including the hip-swivel. It may (should, really) have some additional freedom of motion in the lateral direction at two points. That means 9 "turning wheels" of powered motion, at most 13. A Bradley, which has 6 wheels turning its treads, has 13 including the main turret.

What does all of this mean?

One, the AT-ST isn't very mechanically complex, even in terms of its external properties. Including the enormously complex mechanical processes that go into the Bradley that the AT-ST probably sidesteps by using a fusion-electric complex

Two, the AT-ST may, because of this lack of complexity, have some issues with stability. Since the canon establishes AT-STs falling accounts for a significant percentage of AT-ST casualties, this is not a surprise, but as with above, it's not something that will be taken advantage of by fully modern opposition forces. (Unlike, say, the height of the AT-ST, which makes it a prominent target.)
You're kidding me? This argument is entirely sophistic. Sure, if you count all them moving parts of a vehicle, you'll find a bunch of exposed joints. However, none of these joints are dependent on each other! It's 4 independent wheels, but all the joints of a leg are connected to each other. If one breaks, all joints in that leg will fail. You can also trip since you're not naturally stable anymore. Considering it's already canon that people died from leg failures, you're already well behind the wheeled vehicle which quite possibly never had a "wheel" failure death in its entire history.
The only thing that numbers that suggest an AT-ST would likely fall apart at speed suggest - in this case - that the AT-ST is made of something well beyond our capabilities.

However, when I run the figures on a napkin, it suggests that the AT-ST can be pretty much structurally built from steel or titanium without serious structural problems at <30 mph.
I mean in real life, the cabin will need to carry far more stuff to be useful. There's also another problem I'll get to later.
Which is why we see so many human powered 4 wheeled bikes? We don't. A mountain bike is, plain and simple, the best human-powered wheeled vehicle available.

The basic tradeoff - which is already visible between different wheeled vehicles - is between efficiency (speed) and power (terrain handling).
You've already said it: A bike is very efficient for human powered transportation. Not necessarily the most practical.
Actually, the 6 meter length of the Bradley is critical. The average spacing of trees within a forest is, in many cases, in the 3-4 meter range - which means that while an AT-ST can barely pass through this sort of irregular grid by turning sharply, as can a small jeep, a Bradley is likely to get frequently stuck or have to take down trees. There's nothing unusual about this; it's simply a normal forest environment.
That's actually pretty easy for a tank. Only the big trees are impassible, and a forest of that density (big tree every 3-4 meters) is nearly impassible for any large vehicle due to enormous amount of branches, fallen trees, cramped spots, poor visibility, etc.
Actually, the advantage is to the Bradley in general for an ambush scenario. I'm not assuming it will be super accurate, but the AT-ST does have a good chance of turning the odds on an ambush, assuming the very rudimentary warning systems/sensors are in use.

A draw overall is plenty good enough to show the positive side of the AT-ST's capabilities. Now, if you use something like the BMP-3 or a main battle tank, which has the capability to fire on the move with something that can one-hit kill an AT-ST, the AT-ST's chance of victory starts to approach the inverse of its dramatically greater visibility.

If both can see each other just fine, the AT-ST's smaller target profile is going to make it harder to hit (see again the numbers). If it doesn't consume more power outside of its weapons systems (and, slightly lower mechanical efficiency aside, it's not using an inefficient internal combustion engine and is roughly half the size, that's likely), then it's going to have a smaller heat profile too.
This whole thing basically depends on who has the better warning system, radar and weapon accuracy then. We simply don't know if the AT-ST has the sensor package needed to spot Bradleys or Abrams from 3-4 km out or hit them at that range. One thing is true though, the large profile of the AT-ST makes it an extremely easy thing to spot on radar. Assuming similar radar technology, the tanks have an advantage here.
If you're right, that would be ~20 psi. Half the surface area per unit weight.
Google gave me this:

Entry: 30 ton / 3 m^2 -> lb / in^2

Result: (30 ton) / (3 (m^2)) = 12.9032 pound / (in^2)
Shorter than an AT-ST, but not all that much longer.
Much short mind you. Thinner too. Also has 4 legs with a multi-purpose trunk.
A big enough bomb could bowl an AT-ST over. However, at that size, it's likely to outright kill some or all of a modern IFV's crew at the same range with shrapnel.
Near misses are survivable even for Humvees, but not for a AT-ST. I think statistically, most IEDs fail because they are either spotted or mistimed.
Ahh, but that's more vulnerable to damage and raises your profile.
Not as much as a AT-ST.




There's also some new points I want to bring up. A tank can carry a very heavy gun. An AT-ST can't. Perhaps for conventional cannons it's not a meaningful advantage, but once railguns come along they'll be a big deal. Also, an AT-ST can't cross very uneven terrain with small elevation changes because the feet of the AT-ST can't readily grip the ground. This is no problem for a wheeled vehicle since you are naturally stable and don't have gripping problems as severe.

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Post by Jedi Master Spock » Wed Jan 24, 2007 8:11 am

Nonamer wrote:I've already said this: the treads have only a tiny profile from the front or side. This is virtually impossible to hit. And the real problem are blunt force attacks for legs; a large explosion like that of an IED could easily knock them all out by putting too much much torque on the joints. A tank or Humvee is mostly insulated from such things unless the explosion is close enough to take out the whole vehicle.

You can also bet that the enemy will be creative as they have shown in Iraq, and simply use bombs that eject large objects specifically to take out the legs. Simply assuming that the enemy will use the least effective weapon is totally fallacious, and completely missing the point of "design weaknesses."
I think you're saying that because you haven't run the numbers and haven't seen mine.

The target area of a Bradley's motive system from the side: ~6.7 square meters.
AT-ST leg, single, front: ~1.9 square meters.
AT-ST leg, single, side: ~2.7 meters.

Force required to cause permanent structural damage (loss of plasticity) across the narrowest section of AT-ST leg, assuming solid, but not high strength, steel construction: ~18 meganewtons.
Force required to cause immediate structural failure under above assumptions: ~30 meganewtons.

Minimum projectile to cause internal damage to control and power runs in center of leg: 40mm Bofors gun fired at point blank orthonormal.

Note that at typical angles and distances, a 76mm round would often fail to sever any central control or power runs... and if there's anything wrong with that, it's the assumption that this is steel that we're dealing with, rather than something tougher and lighter, e.g., titanium would be a better material to construct the legs out of.

Long story short? Do try to trip AT-STs. Do try to knock AT-STs off balance. Don't bother trying to damage the legs - it's easier to knock the AT-ST over than to cause any damage to its legs, which are a very difficult target in any case. If you're going to shoot, aim for the cabin.

Force required to accelerate entire AT-ST at five gees, estimated: 735 kilonewtons. I.e., barely over 2% of the force you'd need to break an AT-ST leg. As far as getting the legs with a large object... basically, you need to crash a vehicle at high speed straight into the legs. It's pretty difficult to generate a non-obvious bomb that shoots cars at passing vehicles.
You can walk apparently, but you probably can't run. You also are unlikely to good at walking over rough surfaces with clogs or walking casts anymore. Work boots don't count because they have a flex point near the toes.
Actually, having been in a walking cast almost ten years ago, you can run, albeit awkwardly - it's just not recommended. Same with ski boots - you can clomp around pretty quick, but it's tiring, awkward, and rather slower than you can sprint without them.
You're kidding me? This argument is entirely sophistic. Sure, if you count all them moving parts of a vehicle, you'll find a bunch of exposed joints. However, none of these joints are dependent on each other! It's 4 independent wheels, but all the joints of a leg are connected to each other. If one breaks, all joints in that leg will fail. You can also trip since you're not naturally stable anymore. Considering it's already canon that people died from leg failures, you're already well behind the wheeled vehicle which quite possibly never had a "wheel" failure death in its entire history.
It's easier to blow a Bradley's tread than to dent an AT-ST's leg. For that matter, as the figures above suggest strongly, it's easier to blow up an entire Bradley than to bust an AT-ST's kneecap from the outside. As far as "wheel failure" deaths...

... look at automotive accident records. Blown tires cause lethal accidents just about every single day.
I mean in real life, the cabin will need to carry far more stuff to be useful. There's also another problem I'll get to later.
In real life, we need heavy shells to provide that sort of firepower. As far as supporting two men, targeting equipment, sensors, and the blasters? The AT-ST cabin is ample for that purpose, so far as I can tell.
You've already said it: A bike is very efficient for human powered transportation. Not necessarily the most practical.
The most "practical" human powered vehicle for all-terrain work is the hiking boot, then. The mountain bike is the best all-terrain wheeled human powered vehicle around.
That's actually pretty easy for a tank. Only the big trees are impassible, and a forest of that density (big tree every 3-4 meters) is nearly impassible for any large vehicle due to enormous amount of branches, fallen trees, cramped spots, poor visibility, etc.
Any large wheeled vehicle. The AT-ST is able to navigate a forest of a density that a hummer would find problematic and a larger vehicle would have to clear as it passed; the AT-AT cannot.
This whole thing basically depends on who has the better warning system, radar and weapon accuracy then. We simply don't know if the AT-ST has the sensor package needed to spot Bradleys or Abrams from 3-4 km out or hit them at that range. One thing is true though, the large profile of the AT-ST makes it an extremely easy thing to spot on radar. Assuming similar radar technology, the tanks have an advantage here.
All in all, the AT-ST should have more advanced sensors, but there's no telling, yes.
Result: (30 ton) / (3 (m^2)) = 12.9032 pound / (in^2)
Eheh. I'll check my figures again...

... but a ~15 ton vehicle on ~2.6m^2 is going to beat a ~30 ton vehicle on ~3.0m^2 for this measure regardless.
Much short mind you. Thinner too. Also has 4 legs with a multi-purpose trunk.
Not much thinner. Much shorter, more legs, better sense of balance, more amenable to being trained.
Near misses are survivable even for Humvees, but not for a AT-ST. I think statistically, most IEDs fail because they are either spotted or mistimed.
Actually, the AT-ST's elevation makes it better able to resist the explosive force of ground-based explosive devices (mines or bombs). The only danger lies in bowling the AT-ST over; the fact that the legs are tough and the vulnerable crew cabin is much further from the explosion means you're less likely to get personally perforated by shrapnel or intensely cooked by incendiaries.

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Post by Nonamer » Thu Jan 25, 2007 3:03 am

Jedi Master Spock wrote:
Nonamer wrote:I've already said this: the treads have only a tiny profile from the front or side. This is virtually impossible to hit. And the real problem are blunt force attacks for legs; a large explosion like that of an IED could easily knock them all out by putting too much much torque on the joints. A tank or Humvee is mostly insulated from such things unless the explosion is close enough to take out the whole vehicle.

You can also bet that the enemy will be creative as they have shown in Iraq, and simply use bombs that eject large objects specifically to take out the legs. Simply assuming that the enemy will use the least effective weapon is totally fallacious, and completely missing the point of "design weaknesses."
I think you're saying that because you haven't run the numbers and haven't seen mine.

The target area of a Bradley's motive system from the side: ~6.7 square meters.
AT-ST leg, single, front: ~1.9 square meters.
AT-ST leg, single, side: ~2.7 meters.

Force required to cause permanent structural damage (loss of plasticity) across the narrowest section of AT-ST leg, assuming solid, but not high strength, steel construction: ~18 meganewtons.
Force required to cause immediate structural failure under above assumptions: ~30 meganewtons.

Minimum projectile to cause internal damage to control and power runs in center of leg: 40mm Bofors gun fired at point blank orthonormal.

Note that at typical angles and distances, a 76mm round would often fail to sever any central control or power runs... and if there's anything wrong with that, it's the assumption that this is steel that we're dealing with, rather than something tougher and lighter, e.g., titanium would be a better material to construct the legs out of.

Long story short? Do try to trip AT-STs. Do try to knock AT-STs off balance. Don't bother trying to damage the legs - it's easier to knock the AT-ST over than to cause any damage to its legs, which are a very difficult target in any case. If you're going to shoot, aim for the cabin.

Force required to accelerate entire AT-ST at five gees, estimated: 735 kilonewtons. I.e., barely over 2% of the force you'd need to break an AT-ST leg. As far as getting the legs with a large object... basically, you need to crash a vehicle at high speed straight into the legs. It's pretty difficult to generate a non-obvious bomb that shoots cars at passing vehicles.
Bury it in some large stone blocks and use the rocks to knock it over. Or even an rocket propelled or gun-fired tow cable. Just get creative. In fact that's exactly what the IED is: a creative way to stop a tank when you don't have any money. People aren't stupid enough to attack your strengths, they will always go after your weaknesses.
Actually, having been in a walking cast almost ten years ago, you can run, albeit awkwardly - it's just not recommended. Same with ski boots - you can clomp around pretty quick, but it's tiring, awkward, and rather slower than you can sprint without them.
Running awkwardly would be very dangerous for something the size of an AT-ST.
It's easier to blow a Bradley's tread than to dent an AT-ST's leg. For that matter, as the figures above suggest strongly, it's easier to blow up an entire Bradley than to bust an AT-ST's kneecap from the outside. As far as "wheel failure" deaths...
You have no idea what kind of energy is needed to twist a joint beyond it's ability to recover. One thing is true, it's a lot easier than to break the legs. This is also as fatal as a broken leg. Again, you need to focus on the weaknesses of the design, not the strengths. Here, you are comparing a strength of the walker design to a weakness of the track design which is incorrect.
... look at automotive accident records. Blown tires cause lethal accidents just about every single day.
Because the driver loses control afterwards, and it usually happens in high center-of-gravity SUVs going at high speeds. The failure of the wheel itself may have never killed anyone.
In real life, we need heavy shells to provide that sort of firepower. As far as supporting two men, targeting equipment, sensors, and the blasters? The AT-ST cabin is ample for that purpose, so far as I can tell.
We don't exactly have blasters in real life. And railguns are much likely to be the future than energy weapons (which are very inefficient weapons and create a lot of heat). Realistically an AT-ST is too light to be practical, either today or for the foreseeable future.
The most "practical" human powered vehicle for all-terrain work is the hiking boot, then. The mountain bike is the best all-terrain wheeled human powered vehicle around.
Wrong. A bike is overwhelming more efficient than walking. Something like five times as efficient to be exact. Didn't I say something about wheeled vehicle being more efficient than walking ones?
Any large wheeled vehicle. The AT-ST is able to navigate a forest of a density that a hummer would find problematic and a larger vehicle would have to clear as it passed; the AT-AT cannot.
I doubt it since the AT-ST will be hitting a lot more tree branches than a Humvee. Anyways, assuming the forest is reasonably thick, then neither should have a problem.
All in all, the AT-ST should have more advanced sensors, but there's no telling, yes.
Given the nature of SW warfare, who can say.
Not much thinner. Much shorter, more legs, better sense of balance, more amenable to being trained.
Basically far more suited than an AT-ST for forest life. Possibly a comparison to a jeep may be suitable. It's still all dependent on the size of the object in question.
Actually, the AT-ST's elevation makes it better able to resist the explosive force of ground-based explosive devices (mines or bombs). The only danger lies in bowling the AT-ST over; the fact that the legs are tough and the vulnerable crew cabin is much further from the explosion means you're less likely to get personally perforated by shrapnel or intensely cooked by incendiaries.
Basically the primary weakness of the AT-ST.

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Post by Jedi Master Spock » Thu Jan 25, 2007 5:06 am

Nonamer wrote:Bury it in some large stone blocks and use the rocks to knock it over. Or even an rocket propelled or gun-fired tow cable. Just get creative. In fact that's exactly what the IED is: a creative way to stop a tank when you don't have any money. People aren't stupid enough to attack your strengths, they will always go after your weaknesses.
Of those, a gun-fired tow cable is probably the best idea on the list, provided it anchors well on whatever it's fired at.
You have no idea what kind of energy is needed to twist a joint beyond it's ability to recover. One thing is true, it's a lot easier than to break the legs. This is also as fatal as a broken leg. Again, you need to focus on the weaknesses of the design, not the strengths. Here, you are comparing a strength of the walker design to a weakness of the track design which is incorrect.
Actually, I do have an idea of what kind of force is required.

The problem is that the joints are much larger than the narrowest section of leg - and not very easy to torque out of place. We're still generally talking about meganewtons of force based on the contact areas and assuming a relatively structurally simple "joint," and the sort of specific torque required to pop the knees is not physically easy to apply to a standing AT-ST.

It's really quite something, how durable solid steel bars are. Why, if only the cabin were substantially better armored, the AT-ST would be the equal of a medium tank in its resistance to enemy fire.
Because the driver loses control afterwards, and it usually happens in high center-of-gravity SUVs going at high speeds. The failure of the wheel itself may have never killed anyone.
Loss of control is very often lethal - SUV, Jeep, motorcycle, or AT-ST. That's what failure of the motive system while in motion means.
We don't exactly have blasters in real life. And railguns are much likely to be the future than energy weapons (which are very inefficient weapons and create a lot of heat). Realistically an AT-ST is too light to be practical, either today or for the foreseeable future.
Practical for what? It's a light combat vehicle. IMO, 15 tons isn't too light for a skirmish unit.
Wrong. A bike is overwhelming more efficient than walking. Something like five times as efficient to be exact. Didn't I say something about wheeled vehicle being more efficient than walking ones?
It is more efficient, of course. I've said as much myself. Efficiency traded for terrain handling.
I doubt it since the AT-ST will be hitting a lot more tree branches than a Humvee. Anyways, assuming the forest is reasonably thick, then neither should have a problem.
The Humvee will have more of a problem under a typical forest conditions. The AT-ST isn't going to have as much trouble with branches as the Humvee will with trees...

...and, as I've mentioned, the Humvee is something like a third the overall mass of the AT-ST. It's a much smaller vehicle with a slightly larger ground footprint.
Basically far more suited than an AT-ST for forest life. Possibly a comparison to a jeep may be suitable. It's still all dependent on the size of the object in question.
Forest life isn't the same thing as forest combat, mind. I wouldn't lay too good odds on the elephant unless you gave it ... oh, armor and weapons and trained it to kill chicken walkers.

I mean, we can work out a "squeeze to fire" trigger and belt fed ammunition for something like a Carl Gustav, right?
Basically the primary weakness of the AT-ST.
In summary, the AT-ST's weaknesses are, by modern standards of IFVs, falling over due to a lack of stability, being tall enough to make hiding quite difficult, and (probably) speed in open terrain.

Its strengths are its firepower, terrain handling, and ease of logistical support.

Are we then in agreement for the most part?

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Post by AnonymousRedShirtEnsign » Thu Jan 25, 2007 6:18 am

I, for one, agree with all your summary points except terrain handling, since that is reliant upon stability, and the AT-ST's joints are too simple and limited in their movements for the machine to take advantage of having legs.

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Post by Nonamer » Fri Jan 26, 2007 1:32 am

Jedi Master Spock wrote:Of those, a gun-fired tow cable is probably the best idea on the list, provided it anchors well on whatever it's fired at.
Specifics don't matter, it's the fact that it can be done and done simply.
Actually, I do have an idea of what kind of force is required.

The problem is that the joints are much larger than the narrowest section of leg - and not very easy to torque out of place. We're still generally talking about meganewtons of force based on the contact areas and assuming a relatively structurally simple "joint," and the sort of specific torque required to pop the knees is not physically easy to apply to a standing AT-ST.

It's really quite something, how durable solid steel bars are. Why, if only the cabin were substantially better armored, the AT-ST would be the equal of a medium tank in its resistance to enemy fire.
Yet you've still haven't done anything to show the joints are resilient. They're still exposed joints, and are not held together by anything but the equivalent of muscle fibers or ligaments, and can made to bend by force. We saw in the ROTJ movie, and any substantial tripping action will beat it.
Loss of control is very often lethal - SUV, Jeep, motorcycle, or AT-ST. That's what failure of the motive system while in motion means.
Doesn't happen when stationary.
Practical for what? It's a light combat vehicle. IMO, 15 tons isn't too light for a skirmish unit.
If it wants to stand a chance against real tanks, it certainly would want some heavier weapons.
It is more efficient, of course. I've said as much myself. Efficiency traded for terrain handling.
I've must read something wrong... Anyways, the bike is meant for a massive increase in movement efficiency and not for all terrain purposes.
The Humvee will have more of a problem under a typical forest conditions. The AT-ST isn't going to have as much trouble with branches as the Humvee will with trees...

...and, as I've mentioned, the Humvee is something like a third the overall mass of the AT-ST. It's a much smaller vehicle with a slightly larger ground footprint.
A Bradley would have equally no problem. It can just run over everything that isn't huge.
Forest life isn't the same thing as forest combat, mind. I wouldn't lay too good odds on the elephant unless you gave it ... oh, armor and weapons and trained it to kill chicken walkers.

I mean, we can work out a "squeeze to fire" trigger and belt fed ammunition for something like a Carl Gustav, right?
The point is that the AT-ST is too big to have a genuine advantage over the Bradley or Humvee in a forest. Real forest animals are significantly smaller.
In summary, the AT-ST's weaknesses are, by modern standards of IFVs, falling over due to a lack of stability, being tall enough to make hiding quite difficult, and (probably) speed in open terrain.

Its strengths are its firepower, terrain handling, and ease of logistical support.

Are we then in agreement for the most part?
Minus the terrain handling advantage, clarify speed as "slower nearly all the time," and a dozen or so other disadvantages like reliability, exposed locomotion systems, less carrying capacity, inability to handle a largish gun, etc., then yes, we are in agreement.

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Post by Jedi Master Spock » Fri Jan 26, 2007 3:26 am

Nonamer wrote:Specifics don't matter, it's the fact that it can be done and done simply.
It's not all that easy - or simple. It may be practical in some cases (just as a trebuchet may be practical in some cases), but it's not much of a battlefield weakness.
Yet you've still haven't done anything to show the joints are resilient. They're still exposed joints, and are not held together by anything but the equivalent of muscle fibers or ligaments, and can made to bend by force. We saw in the ROTJ movie, and any substantial tripping action will beat it.
When did we ever see the joints fail in ROTJ? I only recall seeing tripping, falling over, and exploding involved. In the case of the log-tripped AT-ST, for example, there doesn't appear to be any joint failure even after the fall, as seen here. The legs simply lie off to the side of the cabin as it explodes.

As I've said, the amount of surface area of steel in contact with the joints is much greater than the cross-section of the narrowest leg sections, and we can expect a similar order of magnitude of force required to cause structural failure. It's simply not practical. Trying to create a structural failure of the legs or joints is, so far as I can tell, the singular hardest method of trying to kill an AT-ST. It's much easier to topple the AT-ST or just shoot at the cabin.
If it wants to stand a chance against real tanks, it certainly would want some heavier weapons.
Not a valid critique in this case, though it would be if the AT-ST mounted modern weapons. The AT-ST's existing weapons are megajoule range weapons with a high rate of fire - meaning that it has similar energy shots and a higher output of firepower over time compared with modern MBTs 4-5 times as large.
I've must read something wrong... Anyways, the bike is meant for a massive increase in movement efficiency and not for all terrain purposes.
A road bike is designed for optimal efficiency. A mountain bike is designed for optimal terrain handling... and is, quite simply, the best human-powered wheeled vehicle available for all-terrain work.
A Bradley would have equally no problem. It can just run over everything that isn't huge.
A Bradley will have no small amount of difficulty running over a tree a half meter or more thick... which will have to happen with great frequency in a typical forest.
The point is that the AT-ST is too big to have a genuine advantage over the Bradley or Humvee in a forest. Real forest animals are significantly smaller.
The "footprint" of a forest elephant (so to speak) is not all that much greater than the AT-ST. The AT-ST is just small enough to get between the bigger trees in a typical forest - and incidentally just tall enough to step over the thick underbrush and shorter trees that can also be a pain to get through, by the way.

The long and the short of it is that the AT-ST will be able to move more quickly with less noise, fewer visual demonstrations of its passage from the air, leaving less of a trail in doing so.
clarify speed as "slower nearly all the time,"
The top road speed of a Bradley is only 45 mph. The top cross-country speed of AT-STs cited in this thread has been ~30 mph, which would be on the order of a couple strides per second, and is not greatly less.
and a dozen or so other disadvantages like reliability,
Mechanical reliability does not seem to be an issue.
exposed locomotion systems,
The locomotion system is less exposed to damage than the Bradley. I already showed you the surface area figures, explained why it's an even harder target to hit because of its irregular movement.

Now I'll mention a third thing. Miss by as little as 0.2m from the center of the leg and you've often missed entirely. Miss the center of a Bradley's treads by 0.2m, and you'll probably still hit them.
less carrying capacity,
The AT-ST probably carries less than the Bradley because it's a smaller vehicle overall.
inability to handle a largish gun,
Not at all relevant with the AT-ST's blasters compared with modern weapons. The blasters have far more firepower than similarly sized modern cannons.

As a matter of fact, let's put this claim to rest. From the blueprints - the blaster barrel itself appears somewhat larger in pictures, but this could be just the front end, which is shown flared on the blueprints - has an external diameter of 6 cm, with a length of 189 cm. In other words, the blaster barrels appear to have the approximate dimensions of a 45mm/42 gun.

Let's consider a conventional-weapon version of the AT-ST for a minute then, shall we? It mounts dual 45mm/42 guns with some secondary (probably lighter) weapons.

The Bradley mounts a 25mm gun. Most IFVs mount 30mm or smaller guns. The main armament being a 40mm gun is, on the scale of IFV weapons, really quite good; only a very few light fighting vehicles, such as the BMP-3, Centaur, etc, generally classed as light tanks rather than IFVs, mount heavier main guns.

In other words, for a ~15 ton vehicle in the "light combat vehicle" tactical role and designed to terrorize infantry, the AT-ST carries physically large weapons. It, in fact carries guns of a size often expected of a light tank. For example, light Soviet tanks in the WWII era, massing 10-20 tons, typically mounted a single 45mm gun of similar dimensions to one of the AT-ST's blaster cannons.

Granted, they only mounted one 45mm gun rather than two, but that's not too significant. Rebuild the gun assembly and you'd probably be able to squeeze a 76mm anti-tank cannon on there instead.

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Post by Nonamer » Fri Jan 26, 2007 5:16 pm

Jedi Master Spock wrote:It's not all that easy - or simple. It may be practical in some cases (just as a trebuchet may be practical in some cases), but it's not much of a battlefield weakness.
Exactly how does a trebuchet exploit any weakness other than that stone fortresses are not indestructible?
When did we ever see the joints fail in ROTJ? I only recall seeing tripping, falling over, and exploding involved. In the case of the log-tripped AT-ST, for example, there doesn't appear to be any joint failure even after the fall, as seen here. The legs simply lie off to the side of the cabin as it explodes.

As I've said, the amount of surface area of steel in contact with the joints is much greater than the cross-section of the narrowest leg sections, and we can expect a similar order of magnitude of force required to cause structural failure. It's simply not practical. Trying to create a structural failure of the legs or joints is, so far as I can tell, the singular hardest method of trying to kill an AT-ST. It's much easier to topple the AT-ST or just shoot at the cabin.
Then how did they trip? By primitively made rope in fact. If the joints have so much strength to them, then they can snap any nearly any cable.
Not a valid critique in this case, though it would be if the AT-ST mounted modern weapons. The AT-ST's existing weapons are megajoule range weapons with a high rate of fire - meaning that it has similar energy shots and a higher output of firepower over time compared with modern MBTs 4-5 times as large.
I meant that at 15 tons, it's too light to survive anything serious. A single shell from a MBT or a medium sized tank would finish it with ease. It's also very vulnerable to RPG fire or mortars, which are significantly less harmful to full sized tanks.
A road bike is designed for optimal efficiency. A mountain bike is designed for optimal terrain handling... and is, quite simply, the best human-powered wheeled vehicle available for all-terrain work.
In terms of efficiency. A mountain bike is still a bike. It's not necessarily the most effective all-terrain human-powered vehicle. We can easily build something with 3 or 4 wheels and suspension and everything, and it would easily be far better at all-terrain transportation than a mountain bike. However, it's probably not cost effective.
A Bradley will have no small amount of difficulty running over a tree a half meter or more thick... which will have to happen with great frequency in a typical forest.
Most forests are not particularly dense once you get into them. In fact, in order for each large tree to get enough sunlight, they must be fairly spread out. It would be very rare for half-meter wide trees to be dense enough to vehicle passage altogether.
The "footprint" of a forest elephant (so to speak) is not all that much greater than the AT-ST. The AT-ST is just small enough to get between the bigger trees in a typical forest - and incidentally just tall enough to step over the thick underbrush and shorter trees that can also be a pain to get through, by the way.

The long and the short of it is that the AT-ST will be able to move more quickly with less noise, fewer visual demonstrations of its passage from the air, leaving less of a trail in doing so.
An 8m AT-ST, which is about 26 ft, is well into the tree branches. I don't see how it can duck all of those problems when it's that tall. And I doubt a forest of reasonable thickness can leave tracks exposed from above. Everything will be covered up in tree leaves.
The top road speed of a Bradley is only 45 mph. The top cross-country speed of AT-STs cited in this thread has been ~30 mph, which would be on the order of a couple strides per second, and is not greatly less.
First of all, we've never seen it go that fast, and possibly is practically impossible due to the G-forces on the crew. Tanks can be made faster too, but we limit their speeds due to safety reasons.
Mechanical reliability does not seem to be an issue.
In real-life it should be. Too many interdependent high-stress parts.
The locomotion system is less exposed to damage than the Bradley. I already showed you the surface area figures, explained why it's an even harder target to hit because of its irregular movement.
I'm not sure if I've mentioned this already, but a Bradley has very significant redundancy in it's wheels. Only a trend kill will stop it with doing massive damage, and the trend is not easy to hit. Plus the trends are so much lower to the ground and are not exposed from the front, which is probably the mostly likely direction to be hit in normal combat.
Now I'll mention a third thing. Miss by as little as 0.2m from the center of the leg and you've often missed entirely. Miss the center of a Bradley's treads by 0.2m, and you'll probably still hit them.
Or hit the ground or some other piece of armor. Hitting something half a meter off the ground is not easy as hitting something several meters up.
The AT-ST probably carries less than the Bradley because it's a smaller vehicle overall.
A Humvee could still carry more.
Not at all relevant with the AT-ST's blasters compared with modern weapons. The blasters have far more firepower than similarly sized modern cannons.

As a matter of fact, let's put this claim to rest. From the blueprints - the blaster barrel itself appears somewhat larger in pictures, but this could be just the front end, which is shown flared on the blueprints - has an external diameter of 6 cm, with a length of 189 cm. In other words, the blaster barrels appear to have the approximate dimensions of a 45mm/42 gun.

Let's consider a conventional-weapon version of the AT-ST for a minute then, shall we? It mounts dual 45mm/42 guns with some secondary (probably lighter) weapons.

The Bradley mounts a 25mm gun. Most IFVs mount 30mm or smaller guns. The main armament being a 40mm gun is, on the scale of IFV weapons, really quite good; only a very few light fighting vehicles, such as the BMP-3, Centaur, etc, generally classed as light tanks rather than IFVs, mount heavier main guns.

In other words, for a ~15 ton vehicle in the "light combat vehicle" tactical role and designed to terrorize infantry, the AT-ST carries physically large weapons. It, in fact carries guns of a size often expected of a light tank. For example, light Soviet tanks in the WWII era, massing 10-20 tons, typically mounted a single 45mm gun of similar dimensions to one of the AT-ST's blaster cannons.

Granted, they only mounted one 45mm gun rather than two, but that's not too significant. Rebuild the gun assembly and you'd probably be able to squeeze a 76mm anti-tank cannon on there instead.
Impossible, the recoil would be too dangerous for the AT-ST. Any advantage it currently has in terms of weapons is due to its recoilless gun. If you want use anything with recoil, the AT-ST is completely inappropriate.

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