What went into the relationship b/n "Blast" and "Exposure"?

[Guest Guest]

deleted per user request

[JasonC]

Since you aren't likely to get a real answer, a few comments, instead.

First, light mortars are systematically too low in their blast ratings, in CM. The actual blast radius and fragmentation effect of an 81mm mortar round is not much inferior to a 105mm artillery round, and is superior to a 75mm tank gun round. In CM, they have half the rating of the latter. They ought to instead have about the blast effect CM gives to 75mm artillery.

Second, in my experience in CM, about 200 blast delivered can be expected to cause one casualty and pin the target. For men with no cover (some concealment allowed) this can fall to 150 or so, and for good cover it can rise to 300 or so. But this still makes HE much less sensitive to cover effects than small arms fire. Double these and you can expect multiple losses and a high chance of broken, with a pin nearly certain.

Also, it is correct for direct fire HE at typical (short) ranges and therefore accuracies, or for indirect fire at appropriate target sizes (e.g. a whole platoon under the barrage footprint). Small point targets for FOs will reduce the effectiveness per round by a factor of 4-5. Trenches and heavy buildings can also be nearly twice as good against indirect HE as they are against direct.

Put it all together and the worst target for an FO is a single team in a trench, the best is a company brush or wheat (concealment, no cover) with more than a platoon under the barrage footprint. It also means a mortar FO can't be expected to hurt more than 20 men, even hitting large targets in the open, and trying to hit a point target a whole 150 round module can only be expected to hit 2-3 men. Needless to say that is too inefficient to be worth it.

In real life, a registered mortar battery could break up a company attack and keep it from being resumed for hours, inflicting 10-15% casualties in the process. In the game, a mortar FO is only a harassing weapon for defenders catching men without appreciable cover. It will pin a platoon 2 times for 2-4 minutes, inflicting a handful of causalties each time.

The real effect of a registered mortar battery can be approximated by using a 75mm FO instead, with a double or triple ammo load (Russian 82mm, 200 to 250 rounds 76mm, or German 81mm 4 tube, a 75mm with 150, or 6 tube again with 150), firing wide sheaf. Walk the aim point around in "green" shifts, to drizzle in the shells in half minute fire increments, spread over the course of half an hour.

[ May 04, 2008, 03:50 PM: Message edited by: JasonC ]

[Guest Guest]

deleted per user request

[JasonC]

I doubt it, nobody found them very effective. The typical scatter round to round was much larger than the effective blast, that was the problem with the really light ones. Even the American 60mm was marginal, and in the field keeping them supplied with ammo barely worth it.

[Guest Guest]

deleted per user request

[JasonC]

There are multiple offsetting idealizations or model inaccuracies. But their net effect for the lightest mortars is about right. It is the off map FOs firing at larger, company sized targets, that are the most shortchanged by them.

On map mortars are far more accurate in CM than in real life. The reason is, the game treats the enemy unit as the aim point and exact center of the shell dispersion. The side to side dispersion is also on the low side, but the previous is the main effect. It wants to simplify the process of overs and unders and adjusts, and just drop a centered shell dispersion pattern on the target.

The way inherent dispersion makes for misses in real life, however, is more complicated than that. You never know the actual aim point the mortar is pointed at. You just see the last shell, and that shell landed not in the center of its present aim point, but in some smeared oval around it. Then you make an adjustment. You see another shell, in a smeared placement around the new aimpoint. Once you are within 50 meters, you fire for effect. You can't get closer, because you really don't know where the mortar is aimed, any finer than that.

As a result, in addition to the shell dispersion you see in CM, the *aim point* is *also* dispersed, some distance from the *intend* target. The *midpoint* of the later shell pattern is not right over the intended target, but off it by some random leftover, less than 50 meters but probably not zero.

Now, scatter the later shots around that "actual" aim point, different from the intended one. Only shells that "miss", aka scatter, in the right direction and by about the right amount, will actually land right near the originally intended target. And that won't be the fattest part of the shell dispersion distribution, but off center, out on one of the shoulders.

This obviously makes a much bigger difference if the "smear" off center error remaining when you switch to fire for effect and stop the shot to shot corrections, is bigger than the effective blast radius of the mortar round. An 81mm round will suppress men out of 30 meters away. A 50mm round will be lucky to reach 10 meters (it is weaker than a hand grenade, though similar magnitude). Both are going to have to stop correcting once the overs and unders are within 50 meters or so of the intended aim point.

So that is the first idealization. The second, offsetting it, is that small blast is underpowered in CM, compared to reality.

But the third is, the effect of target cover is understated in CM. Take a man standing in the open as an index of exposure, equal to 1. Then a man lying prone in the open is already down to exposure 1/2 to 1/3. And a man who is lying prone in the best immediately available cover (had time to seek it etc), but without field fortification of any kind, can be down to 1/5 to 1/10 of the exposure of a standing man. In a foxhole without overhead cover, but able to duck below ground, that falls to only 1/50th as exposed as a standing man.

Needless to say, few men are standing in a mortar barrage after the first round or two lands. And those first few are likely to be ranging rounds, not directly on target, unless the target is quite large or the mortar is registered, or both. If the rounds are suppressing only a small portion of the overall area per unit of time, men are likely to get to the best available cover, or completely clear. While a barrage thick enough to blanket the area with 30m radii, will pin more of them in the relatively exposed "prone, open, still in the beaten zone", cover effect category.

That makes it considerably harder to make up for smaller oomph per round by just firing more rounds. Already in the smaller effect per round category, 50mm mortars are starting with a 9 to 1 disadvantage. Throw in a likely 2 to 5 times better cover and limit the firing mortars to the 1-3 in a platoon or company support role, and they just aren't going to hurt things before running dry.

Now compare that to a battalion level mortar battery with 4-6 of the heavier tubes, more of them hitting more exposed men, etc. Overall, the 81s are going to be 1-2 orders of magnitude more effective than 50s.

Another thing to notice is that the aiming idealizations in CM favor their use against point targets, whereas the real smearing inaccuracy makes them more useful at larger targets. Plenty of rounds are going to miss the point of aim by a long way - but can hurt men up to 30m away, not 2-8m as in CM. Hence my recommendation to use a bigger round in a wide sheaf, and then walk that wide sheaf around, too.

The result will be moderate danger over a wide area (and kept up for a comparatively long time), rather than intense suppression at one picked location, and very little anywhere else. And total kills will rise directly with the size of the target - men under the beaten zone. Especially if they can't get into truly superior cover.

I hope this helps.

[Guest Guest]

deleted per user request

[DavidFields]

Relationships? Ummm...there are no ....relationships once starts seriously playing, or posting, on CM.

Anyone disagree?

[JasonC]

The inherent accuracy of the 50mm was rated at 35 meters, at a fairly short range (400 meters or so). For the 81mm the figure is 65 meters, at a considerably longer range - at short ranges it would be comparable to the 50mm or nearly so.

For tube artillery, in principle they can be significantly more accurate, but only at quite close ranges or in direct fire. At the ranges they actually typically shot from, they were less accurate than even the 81mm figure. Most of the dispersion is along the axis of fire - the side to side is pretty accurate with rifled guns. But in the long axis, a 155mm howitzer can miss by 150 meters, easy, shot to shot, if the range is long. (Max range is 24 kilometers).

In practice, the tube arty typically called out adjusts in 200 meter increments. Once the target was bracketed, or if a round was observed within 100 meters of the intended target, they'd fire for effect. If it was by bracketing, obviously they split the difference on the over and under, when picking the elevation ("quadrant", technically) to fire the FFE.

They were not able to put the center of the shell dispersion exactly on a 2m by 2m patch of ground, like we do in CM. That is why typical sheafs were not narrow, as you see in CM, but full width. Even the CM target wide sheaf clusters the rounds more to the center than in a real barrage, because a real barrage has 4 (occasionally 6) distinct aim points, spread from one another like the gunline on the firing end. Add in the inherent inaccuracy and the smeared out aim point precision, and a typical tube artillery barrage was really directed at an area more like 200 meters by 200 meters.

In CM, we aim down to the 2m level and are looking for "hits" down to the 20m level. Only GPS guided bombs or rockets have that kind of behavior in the real world. Then we change the fire missions and aim points on the fly, on a tiny time scale, trying to use that exact placement to hit exactly the vulnerable point in the enemy mass. The real world didn't work that way - laser designators and GPS might approximate it in the future, but certainly not in WW II.

CM has the long spread about right for an individual gun, we are just pointing the center of that long oval with a laser pointer, when it ought to be a shotgun. And it shows all rounds aimed at the same point - which is dutifully clobbered - when in reality, they were firing at much wider areas.

They didn't mind because they were also firing at much larger targets. Not one gun or MG or even located platoon, but a whole map region where enemy were known to be. Usually whole companies or battalions of them. Also, the danger zone from the shells was wide, though relatively low at the longer distances; often an entire battalion fired the shoot, etc. Shells weren't as scarce or "expensive" as in CM, but weren't as precise either.

As I've said before, CM arty is shown as a scalpel when in reality it was a bludgeon.

The ineffectiveness of the 50mm in these terms is easy to understand. It needs to hit within about 10-15 meters even to make people duck, and more like 5 meters to kill or wound people. That simply isn't a lot of beaten zone. Sure the 155 shells are landing all over the place, but they are also dangerous to anyone within 50 meters. 81s and 105s are in between, but on the order of 30 meter danger zones. The area covered is going up as the square of those figures. Since the reality is these weapons are saturating a wide area with danger, not carving a deep crater at one point in space, that is the relevant question.

[Guest Guest]

deleted per user request

[Guest Guest]

deleted per user request

[JasonC]

In reality, the cover effectiveness numbers I gave above are reduced by a factor of 2-3 against airbursts, when overhead cover is absent. Meaning prone men in the open are about as vulnerable as standing men to ground bursts; men in best available ad hoc cover are like prone men to those, men in foxholes like best ad hoc cover, to a bit better off in that case, particularly with slit trenches (narrow) rather than wider holes.

But overhead cover makes airbursts ineffective, easily. Like, 100% ineffective or very nearly so. In Korea it was perfectly normal for defenders in position with overhead cover to call VT missions on their own coordinates to "dust themselves off" during infantry overruns, for example.

Overhead cover is effective against smaller caliber ground bursts, too. Proof against 81mm mortars is pretty easy to get. Against 105mm, it takes a double log roof and 2 feet of packed earth or sandbags. But that was a standard readily met by what we'd consider "log bunkers", in CM terms. 155mm and up stuff would collapse such positions with direct hits. Overall, men dug in with serious overhead cover still took losses to heavy enough artillery barrages, but not serious ones. It suppresses by keeping men deep in their holes in that case, it does not kill.

As for the overall effect of the CM idealizations, infantry up outside of foxholes trying to move around and fight from turn to turn, was more vulnerable in reality than it is in CM. It also stayed pinned (and disorganized) for far longer after any serious barrage. Infantry in better cover is too vulnerable to really big HE in CM, since the effect of blast rises too sharply and readily overmatches the limits of CM cover. This makes seriously big HE more valuable in CM, and also moderately favors attackers (the vs. artillery cover differential between attackers and defenders, is modeled as narrower than it really is, I mean).

These effects aren't too serious, because CM heavily restricts access to large amounts of HE. It does understate the role of artillery in defensive schemes, in particular. It rewards frenetic micromanagement of the tiny supply of shells, but in the high CM cost terms, good use of artillery pays for itself in dead enemy and not a whole lot more.

Needless to say there is another issue with the AI, which doesn't know how to use FOs effectively.

[Renaud]

Something I have discovered over years of playing with scenario design: Providing the AI with large numbers or strategically placed TRP will result in heavy AI use of arty. The AI spotters will fire at enemy units moving onto or over AI TRP's, which are also spotted by any other AI unit. A certain number of human-controlled units must be on the TRP, or a continual sequence of TRP's, for a certain period of time to cause the AI to fire arty. This is more effective when the AI is on defense and the human player must move onto or over AI TRP's. Placing snipers or any other AI units within LOS of AI trp's is sufficient to bring them under fire from all AI spotters anywhere on the map.

I leveraged this in the scenario below (Russian assault vs. Axis-AI defense)

Novorossisk - Ozereika