Artillery Rules of Thumb?

[fatherof6]

I know that CM is supposed to be intuitive but the engineer in me finds it very helpful to have "rules of thumb" for situations that rapidly can change.

The main thing I'm looking for now is some sort of idea on the spread of artillery. After killing more of my own troops than the enemy's with an arty strike in a recent PBEM, I thought I'd come here and benefit from other player's experience. I mainly would like to know how close I my troops can get to an arty target before I need to start worrying about friendly fire casualties.

I know big 155mm guns have a much larger fire pattern than 105mm or 75mm, but how much larger? Does it vary with the experience of the FO? Does it vary with countries?

Before I go through the editor and test all these myself and repeat work someone has already done, I thought I would come here and ask.

Thanks,

Glenn

[Guest Mirage2k]

A major factor in the spread pattern is LOS. If the spotter has a good line-of-sight to the target, the pattern should be relatively tight. If he doesn't, watch out.

Experience has more to do with the accurate reporting of the fire delay, but it might also impact the spread...I'm not really sure.

And, as you said, larger-diameter guns will have a larger spread.

-Andrew

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[WendellM]

"After killing more of my own troops than the enemy's with an arty strike in a recent PBEM"

Heh, that rings all too true. My "Murphy's Law" rules of thumb: 1. Never use "Target Wide" unless you have plenty of body bags, and 2. Your incoming "precision" strike will always be uncomfortably close.

Well, those overstate it a bit, but you get my point. I believe what we're seeing is an accurate reflection of the hazards of telling guns several miles away where to fire. Actually, I've been using off-map mortars (due to "point" limits) more often than guns, and it's pretty easy to get an idea of their expected spread as far as I've seen.

It seems that practice/experience is a great teacher - just note how far a "typical" strike deviates from the target point and you'll get the hang of estimating it. Also, you might consider setting the target point a little bit *away* from the target's direction to your nearest troops, just to have a safety margin - the spread will probably still include your actual target just fine, while reducing the risk of friendly casualties somewhat.

Good luck.

[This message has been edited by WendellM (edited 07-29-2000).]

[chrisl]

Do some experiments. Set up some scenarios where you have different exp levels of FO for each size arty, and do some missions with and without LOS. I did this with the gold demo for the 81 mm mortars and got roughly 200mx200m centered on the target for a target in LOS. I haven't gotten around to it for the final version. You'll still occasionally get the wild short that falls on your head, but it will give you a good rule of thumb.

[Bullethead]

<BLOCKQUOTE>quote:</font><HR>The main thing I'm looking for now is some sort of idea on the spread of artillery.<HR></BLOCKQUOTE>

I set up an experiment a while back to determine this. I created a scenario with a number of targets (bullseyes made from rough and brush terrain tiles) spaced 600m apart across flat terrain and shelled them with FOs. I tested the following variables in all possible combinations: FO LOS, TRP, nationality, FO experience, impact pattern selection, distance from FO to target, size of gun, and type of gun.

The results indicate that the following variables have NO EFFECT on size and shape of impact pattern: FO quality, nationality, gun size, and distance from FO to target. The following variables DO have an effect: TRP, LOS, impact pattern selection, and whether the weapons are guns or rockets.

Here are the average sizes of impact patterns under the possible states of the significant variables:

Regular Impact Pattern Selected

LOS and TRP: 100m x 50m pattern oriented E-W

LOS, no TRP: ditto

Blind and TRP: ditto

Blind, no TRP: 200x x 100m pattern oriented E-W

Wide Impact Pattern Selected

LOS and TRP: 200m diam circle

LOS, no TRP: 250-300m diam circle

Blind and TRP: 200m diam circle

Blind, no TRP: 350-400m diam circle

Rockets act very differently. First off, there is no choice in pattern width, you're stuck with the default. Second, neither LOS nor TRPs have any effect. No matter what you do, rockets always produce a 650-700m diam circular pattern.

Note that in all cases, the center of the impact pattern coincided with the point of aim in the center of the target area on the map. IOW, none of these variables affect the accuracy of the fire mission as a whole, only the size and shape of the pattern around the point of aim.

Troop quality, LOS, and TRPs have effects on how long it takes for rounds to start falling. The better the FO's quality, the quicker rounds come. For the same quality FO, the speeds are as follows:

1. LOS and TRP

2. LOS/no TRP and blind/TRP take about the same time, which is about twice as long as 1. above

3. Blind/no TRP takes 3-4 times as long as 2. above

Conclusions:

I think over-all this is pretty realistic. The system seems to assume that the FO is not going to call for FFE until he's sure he can hit the target. Thus, the longer times for the rounds to start for LOS-less conditions abstract the difficulty in adjusting by sound or waiting for smoke to blossum up over the LOS obstructions. And the consistent shapes of the overall impact patterns reflects that no matter what problems the FO has, the gunners are always going to shoot the mission the same way for a given pattern selection.

The only thing I might want to change about all this is the automatic delay to be sure of adjustment onto the desired target area. While this is fine for most situations, sometimes things are so desperate that speed of getting the fire is more important than accuracy and possible friendly losses. So it might be nice to have a "just shoot, DAMMIT!" option to get the rounds falling at a speed comparable to shooting TRPs. But in this case, the center of the resulting pattern would be randomly moved off the point of aim.

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-Bullethead

It was a common custom at that time, in the more romantic females, to see their soldier husbands and sweethearts as Greek heroes, instead of the whoremongering, drunken clowns most of them were. However, the Greek heroes were probably no better, so it was not so far off the mark--Flashman

[WendellM]

"I set up an experiment a while back to determine this."

Wow, thanks for the data, Bullethead, very useful! I don't suppose you'd consider testing off-map mortars under the same conditions? (I ask lazily )

[Bullethead]

<BLOCKQUOTE>quote:</font><HR>Wow, thanks for the data, Bullethead, very useful!<HR></BLOCKQUOTE>

No problem. I needed to do this in conjuction with writing the CMMC arty rules anyway.

<BLOCKQUOTE>quote:</font><HR>I don't suppose you'd consider testing off-map mortars under the same conditions?<HR></BLOCKQUOTE>

Whoops, should have mentioned that. I tested 120mm mortars as above. Their patterns are the same in all conditions as those of conventional guns. The only differences with the 120mm mortars is that are that a) the fire starts faster, and they have a higher rate of fire than a gun of the same size.

I did not test 81mm mortars because these are not arty weapons. However, it would not surprise me if they conformed to the same patterns as everything else. I do know that they have the same sort of quicker response and higher rate of fire as the 120s, though.

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-Bullethead

It was a common custom at that time, in the more romantic females, to see their soldier husbands and sweethearts as Greek heroes, instead of the whoremongering, drunken clowns most of them were. However, the Greek heroes were probably no better, so it was not so far off the mark--Flashman

[chrisl]

That's awesome data. I'm going to copy it out and paste it into my collection of useful CM links/info.

Make sure that guachi sees this and adds it to the FAQ!!

[WendellM]

<BLOCKQUOTE>quote:</font><HR>I tested 120mm mortars as above. Their patterns are the same in all conditions as those of conventional guns. [...] I did not test 81mm mortars because these are not arty weapons. [...] However, it would not surprise me if they conformed to the same patterns

as everything else.<HR></BLOCKQUOTE>

Thanks much! All of your fine research has saved me much "scut work" thus freeing up more time for playing. I really appreciate it!

Wendell

[Seanachai]

Damnation! Bullethead, Mark IV credits tips from you for the performance of his artillery in our current PBEM game. I would appreciate it if you would stop by some time and help me write letters to the families of my infantrymen...

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After witnessing exceptional bravery from his Celtic mercenaries, Alexander the Great called them to him and asked if there was anything they feared. They told him nothing, except that the sky might fall on their heads.

[Thomas Norton]

Bullethead, that was great intel. thank you.

Fatherof6, I too have had some friendly fire problems. Then, I learned something from a player who never seems to have my problems, the AI.

Just last night, I was fighting it when I noticed something strange. It was night and we had run into each other in some sparce woods. After two minutes, I noticed his two squads just get up and run away. Right near the end of the phase.

I thought they must have had enough and were falling back, maybe low on ammo. I planned my moves and hit GO, six seconds later, I saw a little bit of hell.

You ever notice the naval guns have a different sound.

I think the AI knows Bullethead's data. So, when the cannon cocks tell him shot in one or two, the AI pulls his exposed units back.

That way the error ring does not hit them.

So, today, I started looking at when I call in the fire mission and what is the radis of the good guys to ground zero. If I can give it up, then I want my bronze bar heros to start doing what the AI does to me.

Bullethead's data feels right. Plus, once you get the pattern, you can walk it with the threat. Fire long and then adjust, worth a try.

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"The Legitimate object of war is a more perfect peace."

[fatherof6]

Thanks BH. That's just what I was looking for. I always assumed the pattern was bigger for bigger tubes but that obviously isn't the case.

FYI guys, Bullethead is in charge of the arty rules for the CMMC and he's just published a 50+ pg draft of them for review by the GMs. The work he's done for that pales in comparison to the data he just listed. I just hope we can implement these rules because they'll certainly add to the realism of the whole campaign. I can only imagine how much time you've spent working them up.

Thanks again,

Glenn

[Bullethead]

Fo6 said:

<BLOCKQUOTE>quote:</font><HR>FYI guys, Bullethead is in charge of the arty rules for the CMMC and he's just published a 50+ pg draft of them for review by the GMs.<HR></BLOCKQUOTE>

Yeah, but like 10 pages of that is intro text material included on the assumption that most folks have no idea what all arty can do and what has to be done to make that possible. Plus all the rest is written in "rules language" so uses way more words than normal conversation in order to close potential loopholes.

But don't blame this all on me. Jon Sowden (aka JonS) is responsible for at least 1/2 of it all. This has been a collaborative effort from the beginning.

<BLOCKQUOTE>quote:</font><HR>I just hope we can implement these rules because they'll certainly add to the realism of the whole campaign.<HR></BLOCKQUOTE>

Naturally, I think all these rules are the minimum necessary for any realistic treatment of arty at the operational scale.

<BLOCKQUOTE>quote:</font><HR>I can only imagine how much time you've spent working them up.<HR></BLOCKQUOTE>

Jon and I started working on this back in January, each of us adding a bit and then sending it to the other for tweaking. We got up to Rev 31 before Jon got activated for deployment to East Timor a couple weeks ago. So these rules have circled the globe at least 15 times. They are truly, as Jon used to say, "Ubique".

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-Bullethead

It was a common custom at that time, in the more romantic females, to see their soldier husbands and sweethearts as Greek heroes, instead of the whoremongering, drunken clowns most of them were. However, the Greek heroes were probably no better, so it was not so far off the mark--Flashman