Questions & comments for the designers

[John Kettler]

As a former professional military analyst at Hughes Missile Systems Group and Rockwell, I'm both fascinated and disturbed by some of the information presented in your vehicle descriptions.

1. Why, with all the advanced technology presumably developed by the DT timeframe, have you forced users of ATGMs to employ the ancient SACLOS (semiautomatic command to line of sight) guidance mode used by, among others, even the earliest TOW missile (combat debut An Loc, RSVN. 1972)? Granted, your command link consists of neutrinos, not a guidance wire, but from a functional standpoint, the exposure problem for the firer is identical and likely to be lethal. Why are there no fire-and-forget weapons, as presently exemplified by the U.S. Army's Javelin, let alone things like the in-development Common Modular Missile?

2. As any number of reputable references will tell you, a shaped charge jet is NOT plasma, though many believe this to be true.

3. Why is it that the vehicles, despite their admittedly advanced materials, are practically interchangeable with current ones, admittedly with a nod here and there (A-grav) to emerging? technologies? Why do I not see more remoted weapons? Turret crews = poor crew survivability and bigger target.

4. What do you plan to do with regard to things like visual/IR/radar jamming or attack, EMP weapons, multispectral obscurants and the like, all of which already exist in one form or another, much of it operationally deployed?

5. Your vehicle damage model is reminiscent of the shotline damage model used, at least into the early 90s, by the government in the Joint Munitions Effectiveness Manuals. I believe it marks a real advance in computer wargame damage modeling, but as Lorrin Bird, Jeff Duquette and others who did so much on armor penetration modeling for the CM games can tell you, the issue is much more complicated than what you set forth, involving things like projectile shape, projectile design, QC of both penetrator and the target armor, projectile hardness and material quality, shatter gap, variable armor arrays, armor type, ERA (which can degrade, force ricochet of, or even defeat long rod penetrators, etc. Nor is it necessary to penetrate the armor envelope in order to put an AFV out of business, for a tank that can't see to shoot is militarily almost useless. Depending on design, a couple of small projectiles in the turret optronics could blind a Thor, and an EMP hit within maybe hundreds of meters would likely not only do that but destroy comm gear as well.

If you're going to use DU (nasty stuff, that), please be sure to model pyrophoric effects and radioactive contamination of the vehicle struck, the atmosphere downwind and the soil. NATO spent a lot of money cleaning up sites in Croatia hit with DU munitions, and there are hundreds of tons of it

polluting Iraq to this day.

Nonpenetrating hits not only should degrade the armor for subsequent strikes, but may also cause significant damage via shock, heat transfer, etc. As an analogy, consider a medieval warrior who goes into battle fresh. Thus, his shield is intact in both its energy absorptive and blow deflecting properties, likewise his helm. Similarly, his armor is intact,

no rivets are popped, chainmail rings overstressed

or broken, etc. Let's say that I now assail this man with a flurry of mace blows which fall on his shield and helm. What happens? Every blow degrades his shield in both key criteria, resulting in ever greater energy transfer to the bearer, fatiguing or even injuring him. It's even scarier when we're talking the helm, for there it's not a generalized blow to the body, but to, if you would, the key command and control node. There's far less absorptive material here and any degradation of glancing properties increases the likelihood of a damaging, even fatal blow to the head. A mace blow to the head doesn't have to penetrate to temporarily disable or knock out the man inside the helm. The history of armored warfare has plenty of examples of tanks knocked out by concussion, spall, abject terror from being under heavy caliber shelling, bombing, etc. Streams of 20mm fire pinging uselessly off KV-1 heavy tank armor even caused tank abandonment. How? Crew couldn't stand the clangor. Sometimes,

even own systems do it. The Sheridan, for example, was too light for the monstrous 152mm

gun/missile launcher on it. Firing conventional projectiles generated such shock loads that the fire control optics were completely misaligned.

6. Unless you envision something like the system Maritalia uses on advanced diesel subs, in which

enough oxygen is carried for sustained underwater operations, coupled with vessels to store the exhaust products, your vacuum sealed I.C.E. tech

doesn't make a lot of sense. A variant might work, though, in which the vehicle carries its own oxygen (on planets requiring it), but exhausts combustion byproducts to the atmosphere. Certainly, it is possible to envision planets with, say, acetylene in the atmosphere, intake of which would force shutdown of the engine or lead to its destruction in minutes via uncontrolled, untimed detonations.

7. Your approach to modeling HE shell lethality is gutsy. Blast modeling per se isn't all that difficult (falls off as 1/R to the third power), but coupling that with simultaneously modeling frag damage for huge numbers of fragments (suggest your HE employs preformed frags--for analytical simplicity) could put you in processor overload quickly.

8. I see the ion cannon, but where are the HELs (high energy lasers)?

9. Mines--smart and otherwise?

10. Self-healing systems?

11. Combat drugs?

12. Weapon/atmospheric interactions other than drag? Can imagine situations where certain weapons could prove highly embarrassing to the firers.

13. MRLs?

14. Tube artillery?

Looking forward to your reply!

Regards,

John Kettler

[ November 08, 2005, 05:32 AM: Message edited by: John Kettler ]

[ClaytoniousRex]

Hi, John. You raise very interesting, substantive issues!

Why, with all the advanced technology presumably developed by the DT timeframe, have you forced users of ATGMs to employ the ancient SACLOS (semiautomatic command to line of sight) guidance mode?

Actually, ATGM's *do* have a fire-and-forget mode; the units page is simply a bit out-of-date. The gunner can toggle between the manual LOS guidance mode or the fire-and-forget mode. Fire and forget requires taking the time to stabilize and maintain a lock on the target before releasing the weapon, whereas the manual mode allows the gunner to "fire from the hip" in case he really needs to take a snapshot and enemy countermeasures are making a lock too difficult to achieve at that moment. The manual mode also allows the gunner to do creative things with the missile, such as arcing it into the flank of a target. In contrast, the fire and forget mode always does a "pop-up" attack where, just before impact, it gains altitude and then attacks down into the top armor of the target. On rare occasions, this might not be what you want, so you are free to choose.

a shaped charge jet is NOT plasma, though many believe this to be true.

Yes, I was certainly one of those many. So you're saying the molten metals don't get hot enough to literally attain the 4th state of matter, but they're so hot that people clumsily misuse the term plasma for it?

What do you plan to do with regard to things like visual/IR/radar jamming or attack, EMP weapons, multispectral obscurants and the like, all of which already exist in one form or another, much of it operationally deployed?

Some of this question is answered below, but I'll quickly point out that EMP weapons are simulated (as one type of fire mission that can be called in as support), jamming and sensing are simulated both for intelligence and for locking onto targets (and disrupting enemy attempts to attain locks on targets).

Your vehicle damage model is reminiscent

of the shotline damage model used...the issue is much more complicated than what you set forth

Agreed! The damage model, while detailed and far more robust than what you would find in almost any game on the market (excepting only the rare anomaly like some of Battlefront's games), it is certainly not (yet) a complete simulation of every detail that could have possibly been modelled. Everything you laid out above is interesting stuff to consider adding to the damage model, and we will definitely continue to improve it over time.

Tube artillery?

Various kinds of artillery support are available as "off-map" support assets that can be called in, though they aren't physically present on the battlefield in-game.

Almost all of your other points are basically asking the question, "Where's the super high-tech stuff? Why is this stuff so familiar to us backward 21st century has-beens?"

The answer to that question is given by the history which leads into the setting for DropTeam. The region of the galaxy where DropTeam takes place, called The Rim, is in the grips of a technological dark age. Combatants in The Rim are making do with the technological remnants left behind by previous generations, having already lost much of the higher knowledge and infrastructural base required to produce and maintain the more exotic, high-tech weaponry that used to be common. However, they're still able to coax their aging (and gradually eroding) Liveships into producing *some* of the types of weapons used by past generations (mostly those that were being sold to the people of The Rim for their own internal conflicts). This leads to a colorful and sometimes shocking juxstaposition of low and high tech equipment being used on battlefields in The Rim at this particular point in history. It is, of course, a temporary state of affairs, since the rest of the galaxy is still fighting high-tech wars with everything ranging from nano-scale weaponry to fully autonomous AI systems, etc. But this temporary window in this time and place is where DropTeam is set, for precisely the reason that it's such an interesting and colorful time and place to simulate actions in.

We very much hope in subsequent titles to explore the future of The Rim, as civilization emerges from the ashes and more of the exotic high-tech systems come back into play, and also other parts of the galaxy where these systems haven't fallen into such wide-scale disuse.

This leads directly back into previous discussions on the same topic, started by Peter Cairns, so you might want to check that earlier thread out, too.

[flamingknives]

Originally posted by ClaytoniousRex:

</font><blockquote>quote:</font><hr />a shaped charge jet is NOT plasma, though many believe this to be true.

Yes, I was certainly one of those many. So you're saying the molten metals don't get hot enough to literally attain the 4th state of matter, but they're so hot that people clumsily misuse the term plasma for it? </font>

[Gen. Lee Annoying]

This may be a little bit off topic but bear with me, it is in regards to everyone's annoyance with the lack of ultraspophisticated equipment. As always the linch pin is the back story but frankly I'm not sure everyone buys it. So here's my stab at an analogy. Picture yourself a person with all the latest and greatest weaponry and gizmos. Now you decide that you no longer want to belong to the corrupt or unjust society within which you exist. So with your advanced technology you move to an new block of real estate, one you can start your own little society along the lines of what you see as "right" and in a location where you will be cut off from all vestiges and corruption of your previous residence. After seeing this other adventurous types decide this is the way to go and move in and make their own little societies that may or may not recognize the beliefs and values that your little enclave cling to. Inevitably coflict errupts and you having the advanced technology begin to use it. After several long and protracted confilicts many years have passed you have exhauseted almost all of your technology since by renouncing your association with the old regieme you also no longer receive any assitance and have been branded a danger to your former society. As this time has passed ammunition has grown scarce and the technological superiority you once held has fallen into decay...... your conctruction tools once forrmidable and felible are limited due to lack of material and ill-repair since you were qualified to operate the epuipment but not service it. So you still retain rudimenary capabilities but to return your tools to thier original state they require spare parts and callibration. The two things you are lacking. So now at this point you must resort to technologies that are easily produced which require only rudimentary precision and tolerances. So in the end you are stuck with inferior product from superior tools due to social, political and physical conditions resulting from your choice to strike out on your own.

As always this is just my opinion....... I'm just getting tired of the continuing questioning about the "advanced technologies" that are missing when as always the reasons are spelled out repeatedly. The advanced technologies are something that should perhaps be considered for mods and addons that follow the return to greatness of our downtrodden and desperate society?......

The idea that we as addon makers and modders could be the catalyst for our own rise from the dark ages is both entertaining and quite exciting.

I hope I've made my point as objectively as possible and that no offence is garnered from it.

[Tarquelne]

It's much simpler to pretend that the super technologies require special radiation from Earth's Yellow Sun. And Space, being full of kryptonite, has a suppressive effect.

Speaking of kryptonite, I'm just happy DropTeam doesn't have some super-rare mineral or whatnot that for some odd reason controls access to high tech stuff. (Though I assume that he who controls the Spice controls the universe.) The backstory might come to present anti-matter as a limiting resource, but that - thank goodness - isn't the same.

[John Kettler]

ClaytoniousRex,

Thank you for the clarifications, info, and back story on the game. As far as the ATGM flank attack concept goes, I really don't grok that. If we were talking a, say, Mk 48 torpedo, then I could come up with something which might work, since I could order the fish to run so many hundred meters then execute a turn so that I have a submarine that's broadside to my attack, at which point I can either continue the attack under wire guidance or have the fish autonomously lock on, then release it for terminal phase. Am somewhat baffled as to how you'd do this with a direct LOS neutrino link.

Even in my TOW days I never heard such a concept mentioned, let alone saw it attempted. You might be able to do something like this with the in-development? FOG-M (fiber optic guided missile--medium), in which the seeker is in the missile and POV is from the missile, whereas TOW has always been operator POV. At range, and even with telescopic sights, a TOW gunner has enough to deal with just trying to get a center of mass hit

on a small maneuvering target.

Turning now to armored warfare, I highly recommend

you get and read, if you haven't already, BFC's

THE BATTERY COMMANDER, HIS BATMAN, AND A COOK, for it's full of armored warfare detail I've never seen before, including the morale effects of even a partial penetration. Gun hits, jammed turrets, stuck hatches, attempting to move after firing in pitched battle, never knowing whether the tank can still move because of road wheel damage, shattered track or tracks, etc. Notice, too, cases in which

C3 is lost because of antenna's being shot away, CP overrun, etc.

On the plus side for you, since there is no APHE, at least you won't have to model the fact that a partial penetration in which the projectile doesn't completely enter the fighting compartment can still K-kill the tank. KE projectiles obviously won't explode in this situation. It occurs to me, though, that you may wish to consider leaks in high vacuum and/or toxic atmospheric environments.

Regards,

John Kettler

[Floydii]

Firstly, I have come across this game in the post-HDR screenshots period, So the Heavy Gear 2 style tanks are what caught my eye (brilliant). This looks exceptionally promising given the 'realistic' sci-fi warfare. I'd say that tech wise.. this game could comfortably associate with 'Ground Control' (by Massive Games), ie, slug throwers and tracks alongside plasma cannons and hover tanks. No instant megadeath-ray beams.. this is good.

Right, questions. It has been alluded to that there will be infantry in this game. Some screens would be nice, but what really interests me is how will they be implemented? individually or squads? further more, will they be directly controllable (FPS style) and will they actually be able to hide in trees/long grass/built-up areas (ala 'Steelbeasts'.. good) or be picked off from 5km away (ala M1 Tank platoon 2.. bad).

How extensive will the AI be? Will it be capable of controlling a whole team from command down to individual tanks? or will it have to rely on the mission designer setting up waypoints/triggers to give the allusion of Tactical command? Given the flag/objective based nature of the gameplay you have outlined, I am hoping for the former, as dialup doesn't do MP that well.

Will Vehicles have the option of being put in Platoons/Troops (2-6 vehicles?) that actually work in mutual protection? Even if they just move around behind the lead tank with their turrets scanning a relevant arc would be good enough. Even better would be the ability to attach/detach vehicles ala 'Force21' by Redstorm Games.

Those are my main questions. Again, I think that this game looks pretty sweet from both a visual and gameplay point of view, I'll be watching with great anticipation.

Regards,

Floydii.

[Devil M]

Originally posted by John Kettler:

1. Why, with all the advanced technology presumably developed by the DT timeframe, have you forced users of ATGMs to employ the ancient SACLOS (semiautomatic command to line of sight) guidance mode used by, among others, even the earliest TOW missile (combat debut An Loc, RSVN. 1972)? Granted, your command link consists of neutrinos, not a guidance wire, but from a functional standpoint, the exposure problem for the firer is identical and likely to be lethal. Why are there no fire-and-forget weapons, as presently exemplified by the U.S. Army's Javelin, let alone things like the in-development Common Modular Missile?

For gameplay purposes I don't see the advantage in scores of automatic homing missiles dominating the battlefield. Part of the fun should include the tense waiting for the target to present an optimal profile so that the missile operator has the choice between a safer, less effective firing solution or a better one in the face of mounting danger during the greater time while exposed; the tension for the player guiding the missile during that critical phase while hoping that he isn't detected provides for still more enthralling gameplay. In other words, you risk arcade twitch factor if pressing the launch button is all that is required in lieu of setting up your units so that their firepower is optimized, considering the interaction on their strengths and weaknesses, and so on.

The designers don't always have to conform to every logical outgrowth of what we expect to be the case based on current projections. Otherwise, this sort of analysis has no end: "Where are the triple barrelled plasma and particle projection cannons! You're still using tracked vehicles- where are the mechanized limbs! Infanty rocket packs! Rail guns! Satellite delivered lasers and missiles!"

If you're going to use DU (nasty stuff, that), please be sure to model pyrophoric effects and radioactive contamination of the vehicle struck, the atmosphere downwind and the soil.

What? The people who deal with this are concerned with environmental cleanup long after the battle is over. The toxic waste management of Tungsten and dU filaments is probably well outside the scope of what matters here.

Nonpenetrating hits not only should degrade the armor for subsequent strikes,

Are you talking about a hit-point based armor model? This would only sort of make sense in the context of first generation ERA arrays as the reactive bricks are used up from subsequent hits in the same local area.

As an analogy, consider a medieval warrior who goes into battle fresh...

The analogy falls- AFV armor isn't malleable in the sense that you're describing. You don't hit it with a blunt instrument and it deforms. Whether we are talking about a kinetic energy penetrator or chemical energy round the penetrating force is concentrated into a very small area: you may only be able to put two fingers through the hole as such. Now the spalling may shred the crew to pieces or touch off sympathetic reactions in the ammunition magazine, but whether this happens isn't the result of 'degraded' armor.

If you're talking about the effects of HE squash head rounds, why should we assume that spall liners and spaced armor would not have effectively mitigated that?

[ December 03, 2005, 02:57 PM: Message edited by: Devil M ]

[flamingknives]

Actually, AFV armour is malleable in almost exactly the sense John is describing, but being as it's much thicker the visual effect is different.

Any impact stopped will have its energy absorbed by the armour, which will cause micro-cracking, work-hardening and all sorts of cumulative damage.

HESH rounds might not be effective for first round kills, but there's alot of HE in a 120mm round. Enough to KO a Challenger 2 be striking the open commander's hatch.

[Devil M]

Originally posted by flamingknives:

Actually, AFV armour is malleable in almost exactly the sense John is describing, but being as it's much thicker the visual effect is different.

Any impact stopped will have its energy absorbed by the armour, which will cause micro-cracking, work-hardening and all sorts of cumulative damage.

It was described in much different terms than that, let alone the notion of 'almost exactly.' Some of it was a discussion of the crew's morale rather than a quantified analyis of material science- there is nothing wrong with that, but that dosen't by itself support the analogy of a suit of armor.

HESH rounds might not be effective for first round kills, but there's alot of HE in a 120mm round. Enough to KO a Challenger 2 be striking the open commander's hatch.

This isn't the point- no one is disputing that HE fragments can't rain down into the fighting compartment and set off stored ammunition, or that armor spall wouldn't do this if the HESH round impacted on the thin turret roof (it's not clear which was exactly the case- the round may have just hit and sheared away the open hatch without making contact with the turret, but the outcome is still just the same). The analogy though that the vehicle occupants suffer the effects in exactly the same same way as someone wearing a suit of armor taking repeated blows isn't very accurate. Combat injuries have been extremely consistent with armor spall and burns in most cases. Now you might get knocked around and bump into something in the fighting compartment, but this can happen anyway whether conducting a road march or just by fidgeting around inside the vehicle.

The closest scenario I can fathom where the analogy might even begin to resemble this case probably would occur where overmatch of the armor occurs anyway- say on the turret roof by an artillery delivered HE round or bomblet, or some top attack HEAT round, in which case the concussion effect really becomes secondary to the penetration. But otherwise the analogy is not consistent with any knocked out vehicle I've ever seen. Sometimes it's not very dramatic at all- you might see an entry hole about the diameter of a shot glass with burn marks extending out a bit and that's about it.

[ December 03, 2005, 03:00 PM: Message edited by: Devil M ]

[Devil M]

You don't see the glacis plate on this T-55 deforming or denting in-

http://www.globalsecurity.org/military/world/iraq/images/t-55_iraq-2003.jpg

All the other damage is the result of the subsequent fire that burned out the vehicle. Tracks will melt, external equipment will be scorched or blown off, but there doesn't look like any blunt instrument trauma on the hull.

[flamingknives]

I'm just too lazy to read back up the thread

My point was more along the lines of degradation of the armour. if you can stop a hit from a modern KE round, repeated hits will degrade the armour, ERA of any generation or not.

It will also do things like knock out useful gubbins like sights, comms etc.

Basically, you can't absorb a megajoule of energy without any negative effects.

[Devil M]

Originally posted by flamingknives:

My point was more along the lines of degradation of the armour. if you can stop a hit from a modern KE round, repeated hits will degrade the armour,

Perhaps, but the question remains whether this will be of any practical value- modern engagments are of the sort now where you don't have the chance to experience repeated hits to see this through. The lethality of modern projectiles is such that successful scores often mean first round kills. It's probably not going to be the case that you would receive a dozen or so hits to the same location in any engagement.

This also ignores the angle of attack, the type of projectile, and that furthermore modern composite and laminate armors are of a different character than simple comparison to RHAe face hardened steel- and nowhere near the properties of a medieval suit of armor.

It will also do things like knock out useful gubbins like sights, comms etc.

Well that is true, but it's a different animal.

[ December 03, 2005, 03:03 PM: Message edited by: Devil M ]

[flamingknives]

Ah, but modern engagements are nearly always asymmetric, while "DropTeam" is much more likely to be evenly balanced.

Stick a pair of Abrams facing each other at 2000m, hull down, and they'll bounce shots off each other all day, provided each shot hits fresh armour. It's not a case of dozens of hits, but potentially more than one.

Modern composite armours are even more prone to cumulative damage, as some of the layers break to absorb the impact energy.

[Devil M]

Originally posted by flamingknives:

Stick a pair of Abrams facing each other at 2000m, hull down, and they'll bounce shots off each other all day, provided each shot hits fresh armour. It's not a case of dozens of hits, but potentially more than one.

It sounds as though the comparison is no longer apt. Remember that the analogy previously held that the cumulative damage would eventually make short work of the armor as in a blunt weapon crushing and deforming it across a broad area. The only realistic notion now is that each successive hit would have to score right on top of one another, which is unlikely in practice.

Across the frontal arc however M829A1 and A3 ammunition could conceivably knock out an M1- even the pathetic BM15 steel rounds from ancient Soviet stocks the Iraqis were using as front line ammo could theoretically penetrate with a lucky hit to the driver's compartment, straight down through the gun into the breach, or in the small gap under the gun mantlet into the turret ring; in a few cases though they just stuck like arrows into the turret with no further consequences.

Modern composite armours are even more prone to cumulative damage, as some of the layers break to absorb the impact energy.

This has more to do with the way they defeat HEAT rounds rather than solid shot as it only refers to the light composite materials: ceramics, plastics, sand, glass: it certainly dosen't behave like a suit of armor, which isn't also going to have a layer of depleted uranium mesh sandwiched in there and which simply relies on pure thickness rather than the chemical properties of the material. I still think the case is being overstated if it is compared to the tensile strength and malleable properties of a suit of armor, especially since they can't be shown to behave like one another under any circumstance- this doesn't even happen on an intuitive level to the layman. It's a gross statement that doesn't quite indicate what happens in practice- losses are attributed to penetrations on weak spots rather than a descriptiton of 'cumulative damage'

[ December 03, 2005, 05:55 PM: Message edited by: Devil M ]

[flamingknives]

OK, so the analogy isn't fantastic, but it's still not that limited. A hit to one point will still degrade an area as the cracking etc spreads out. Delamination, edge effects, heating etc are not restricted to a small area. The comparison isn't down to the material makeup and properties of the armour, but that repeated hits will degrade it.

High-energy, non-linear events are non-intuitive, even to non-laymen, but the cumulative damage to a suit of armour is more understandable, and hence, a suitable analogy, even if the actual mechanics differ.

The figures I've seen for M829A1 and M1A2 turret front armour has the turret overmatching the projectile.

[Devil M]

*Double post*

[ December 04, 2005, 06:14 AM: Message edited by: Devil M ]

[Devil M]

There was an excellent discussion on tank armor and KE projectiles a little over a year ago at the Steel Beasts website led none other by the legendary Vasily Fofanov- it challenges many notions including general assumptions about ricochets. But Vasily presents a nice little illustration of critical areas on the frontal aspect of the M1- granted the illustration here is an M1A1, but for the purpose here the shot traps would also apply to the M1A2:

http://www.steelbeasts.com/index.php?name=PNphpBB2&file=viewtopic&t=3549&start=0

[flamingknives]

That is a good reference, Devil M. Critical areas are important, but don't need to be modelled directly. Statistical representation is good enough.

Note also that Armour and systems degredation from multiple hits is also discussed.

[Devil M]

Well someone asked the question about whether this was going to be modelled or not in Steel Beasts- I don't know if this were a rhetorical or hypothetical quesion. No one even responded to it to shed light on it, I suspect because they wouldn't know the answer: the actual effects would have to be based on guess work and a statistical calculation with 'common sense' guesswork invloved. You could take this information with a grain of salt, or presume to build a game around it, depending on your priorities. In a game such as Steel Beasts, you can set up unlikely situations such as shooting at an M1 for target practice all day. The armor model while adequate is not a definitive one, since it is not designed to be so, but rather teach fundamental lessons that are considered to be 'good enough' given available information.

It's not that I disallow the concept; I am however guarded against the practical consideration where it becomes important to model in a simulation. Recent combat experience doesn't yield much data on this- there are too few real life examples of individual vehicles sustaining enough hits in the same location to interpolate information, or otherwise the information has been kept secret.

An engineer or someone who could provide this information probably would not anyway or else be in violation of OPSEC. In other words, those who provide definitive answers are usually just using alot of guesswork, since the ones who really know wouldn't be talking.

[ December 04, 2005, 08:59 AM: Message edited by: Devil M ]

[John Kettler]

Devil M,

The medieval armor analogy is nowhere nearly as bad as you paint it to be. Even a knight in all but late full plate has less well protected areas, which are mailed, the armor is worn over an arming jacket, which is padded to help dissipate the force of blows

and distribute the armor's weight, and the helm is worn over a mailed hood, with a pad to help spread the helm's weight and again provide some cushion against overhead blows. The design of the armor is all about converting direct hits into glancing blows, and my point was that in the heat of battle, that armor and shield become more and more degraded in both ability to generate such glancing blows and the ability to spread out and dissipate

the energy from blows received. These act to generate a progressive degradation in the overall utility of the knight's protection, exposing him to wounding or worse. A mace or flail was good for showing the progressive destruction of glancing surfaces, but I could've used overhead blows from a sword, axe or bill weapon blows, or even spear thrusts. Now, let's consider a tank.

Simpkin rated the KE of a modern tank round (was probably thinking Chieftain 120mm) as equivalent to a large bus at 35 kph, with said force concentrated into the area of the penetrator (about 40mm diameter). We know that the recoil forces are such that the entire, say, 60 short ton tank, despite very good recuperators, heaves violently. Most of that energy is now delivered to a target tank at impact, but how much of it actually gets through is a function of firing angle, armor slope, armor quality, armor density, composition and structural properties, ditto for the projectile, plus shape, hardness, how well it bites into the armor hit, and much more. Let's take a simple case, early composite armor consisting of a steel, ceramic, steel sandwich. This was the T-95 design the U.S. almost built in the '50s, but the more conventional M-48 design won out. The projectile defeat concept is basically to put a series of rapidly changing stresses on the penetrator, causing it to fail mechanically, while dissipating the energy it delivers. So, the round hits the outer steel, is degraded and slowed while penetrating it, then hits the superhard ceramic layer, which puts incredible stress on the already degraded penetrator and at the same time absorbs enormous amounts of energy by cracking and splitting. Anything left of the penetrator, by now anything but optimally shaped as a penetrator, and quite possibly out of plane, must now exit through another substantial layer of steel.

This, by the way, is essentially the armor design for the early M-1 models (before the DU was added). I know because in the early 80s I saw the unclassified Army letter removing M1 vierceous (glass) cored armor from Special Access requirements. The T-95 program was cancelled, but the Russians launched ammo developments to counter it, as we found to our horror post Yom Kippur when

"crummy export model" stuff captured by the Israelis turned out to be capable of killing the M1 frontally. This is the major reason that all the vanilla M1s were crash replaced with HAs from V Corps before Desert Storm started.

Returning to our thought model, consider what happens when that same armor array is struck repeatedly. The once smooth surface is not as smooth (reduced ricochet chance), the top layer (to some radius X) has had its metallurgical properties altered (not to the good), the ceramic layer is no longer homogeneous, no longer as effectively hard and dense, and can't spread impact loads as well as it could before, which means that the inner armor has to do a lot more work. Even if no penetration results, each successive shot transfers more and more energy to the victim tank, exposing systems and crew alike

to shock loads which benefit neither.

Now, let me give you a small sample about what the impact loads can do. The Army used to operate specially modded M-103 (M-48 family 120mm armed Stalin equivalent) tanks with crews in them for TOW live fire training with dummy warheads. Periscopes were armored, etc., but the KE of even a coasting (fuel spent) TOW 2-3km downrange was so immense that major rework had to be done, for the blow was doing things like smashing in even the armor housed vision blocks and endangering the crews. I believe the Army eventually gave up and went with radio control for the target tanks.

Here's another example of shock damage. The M-551 Sheridan was fitted with a 152mm gun/missile system. The weapon fired HE?, HEAT and cannister, plus the IR beamriding Shillelagh ATGM. The problem, though, was that the Sheridan was way too light for the recoil forces created when the cannon fired conventionally. In fact, it was found that doing so completely decollimated and misaligned the optics for the Shillelagh's guidance. A spent Maverick missile at impact had a significant fraction (60-70%) of the KE of a 16" shell at impact, so much so that at Hughes we used to joke that the warhead was there in case we missed. An imaging IR version with inert warhead utterly caved in and destroyed an M-48's engine compartment, setting the target tank ablaze. Jacques Littlefield is trying to turn that hulk into a runner.

I'm not saying I know how to model the issue I've raised, nor am I arguing for using hit points. Rather, I'm arguing that there is a rational basis

for raising this issue. I'm curious to see what, if anything, the designers will do to address this matter.

Before I close, let's also look at resistance of such an early composite array to HEAT. A vanilla HEAT projectile will penetrate the steel but be defeated by the ceramic, which interacts with the jet in ways the

HEAT projectile jet can't handle, being radically different in density and in thermal capacity. The inner plate then keeps the nastiness out. A precursor charges change matters drastically, though, by giving the jet a clean shot at a homogeneous armor array. The undegraded jet then has the oomph to pierce the ceramic and defeat the inner plate. Urk! Now, when you move into more complex composite armor, things become very iffy.

Why? Because everything depends on what's in the array, in what sequence, and how it's spaced. In static firing trials against estimated Soviet composite arrays a terrible discovery was made:

even minor repositioning of those elements meant the difference between K-kill and no kill, and there was no way to know by simply measuring the thickness of the armor array housing. This was an advanced missile warhead from the 80s.

All in all, I think that a composite array will tolerate repeated HEAT impacts much better than repeated KE strikes.

Regards,

John Kettler

[ December 09, 2005, 12:30 AM: Message edited by: John Kettler ]

[Devil M]

You would be safer with a lightweight suit of armor vs sub-caliber long rod penetrator- there's simply not as much material flowing out of the way of the projectile, spalling back into the crew compartment; the risks become that much more minimized.

I see this analogy closer if we were talking about full caliber hard-capped AP shot before modern tank designs switched over to HVAPDS, or if we were talking bobmbardment of 16" or 155mm projectiles impacting on the turret roof: modern armor hasn't really progressed in the sense that it offers immunity by mere thickness against a slow moving, heavy slug- so in that sense I agree with you. But I have a difficult time with the analogy where it concerns the concentration of energy into a much smaller area such as from modern sub-caliber penetrators and HEAT rounds. Overmatched armor is defeated regardless of continued hits.

[flamingknives]

Overmatched armor is defeated regardless of continued hits.

Of course it is. it would be ludicrous to suggest otherwise. By it's very definition a projectile that overmatches armour will defeat the armour.

The analogy rings true (pardon the pun) for cases where the armour is not overmatched in the normal course of events. if the armour is capable of stopping a KE round, it still has to dissapate and absorb in excess of 5 MJ of energy. The various layers of composite armour, especially ceramics, act to spread the impact of the projectile over a wider area.

[Caseck]

If a HEAT charge isn't a plasma jet...

Why then does a HEAT jet look like a straight fork of lightning?

It LOOKS like plasma... Lightning is plasma, right? The copper is definitely superheated in the liner... There isn't that much MASS in a HEAT warhead. I mean, they're REALLY LIGHT!

I understand a platter charge is kinetic, but that's a whole different animal from a copper lined shaped charge! Am I messed up here?

I mean, it's a light jacket of COPPER, how hard can it be to vaporize? Isn't that enough for it to enter a plasma state?

[flamingknives]

Yep, you're messed up somewhere there.

Metallugical analysis of material recovered from a shaped charge jet that hasn't hit anything indicates that no phase change has taken place. It hasn't even melted.

It does seem counter-intuitive, but most stuff that goes on at those speeds is. You'll get heating effects with passage through a medium, such as air or armour, but it is hypervelocity kinetic energy that makes a shaped charge work. They're not particularly light either.

Finally, that you can take x-rays of a shaped charge jet argues quite elegantly that it is not a gas, much less plasma.