Artillery Test vs. Rooftop troops, v1.31

[c3k]

Gents,

There has been some (ahem) talk about troops on rooftops and their resistance to artillery. I was recently fortunate enough to have been invited to General Land Warfare Testing Center's artillery range. There, they allowed me to run some tests on their East Anglia range. The MOD was kind enough to lend the use of some 105mm guns from The Queen's Light Prancing Into Battle With Skirts Atwirling Royal Artillery, as well as some thousands of rounds. I would be remiss if I did not mention the catering, provided by Mrs. Fabersham's sandwich shop.

The test would not have been possible without the hundreds of Syrian volunteers, graciously provided by Mr. Assad. They were quite motivated, at least at the beginning of the test, and their presence made the test the resounding success it was. (Our staff psychologist did advise us that the test subjects might lose some enthusiasm once the test began. Due to his sage advice, we took precautions to ensure "cold feet" did not render the test worthless. His suggestions led to the tall walls and alligator filled swamps around the impact zones.)

The test itself was conducted against several different target sets. They were:

- Infantry on walled rooftops

- Infantry on unwalled rooftops

- Infantry on the 2nd floor of a 2 level building

- Infantry on paved ground

- Infantry on dirt

- Infantry in rubble (from demolished 2 level buildings)

Each target set contained a platoon of Syrians (Fanatic, Elite, well-led, fully supplied). Each platoon started with 27 men. (They did not quite finish that way.)

Each target set was targeted by 2 tubes of 105mm, linear, 32 or 33 meters long, medium, medium, personnel. (Except the target set INSIDE the buildings, on the 2nd floor. They were targeted in a similar fashion, except the fuzing was set to "general".) This meant about 20 to 24 rounds of 105 came down in approximately 200 seconds. The target sets were 16 by 48 meters long. (2x6 map squares.) They consisted of 3 buildings, adjoining one another. The target lines went from the far left of the rooftop to the far right of the rooftop. I ran dozens of iterations.

Here are the average number of survivors (with standard deviation).

- Infantry on walled rooftops - 13/3.5

- Infantry on unwalled rooftops - 13/3.5

- Infantry on the 2nd floor of a 2 level building - 23/3.5

- Infantry on paved ground - .5/.7

- Infantry on dirt - .4/.7

- Infantry in rubble (from demolished 2 level buildings) - 2.75/1.6

Conclusions:

Walled vs. unwalled rooftops make no difference to survivability against airburst 105mm shells. In each case, troops on rooftops maintained cohesion and fighting ability despite 20 or more impacts along a 100 foot line. The survivor number ranged from 7 to 21. Firing 105mm against troops on rooftops will cause approximately 50% casualties, but will not negate the defensive qualities of the troops on a roof.

Troops INSIDE a building, on the top floor, are basically immune to artillery. The average number of survivors means that 20-24 105 shells, fuzed at GENERAL, create 15% casualties. 105mm is ineffective against troops in buildings.

Infantry in rubble gains a SLIGHT advantage against airburst 105's compared to troops lying down on pavement or dirt.

I can make the scenarios I created available. I have not yet tested 81mm or 155mm.

I know that causing 50% casualties is not minor, but compare what happened to troops constrained to the same footprint in open ground: essentially no one survived. Yet, rooftops confer a 50% survivability chance (whether walled or not). I am aware that the game may model rooftops which are not smooth. Mideast roofs have stairwells, dips, mini-walls, water heaters, oil tanks, etc. However, if you then take the desiderata on a roof and compare it to a RUBBLED BUILDING, which one should provide more cover? I would suppose rubble; compare rooftop numbers to the rubble numbers. Rooftops provide a greater than 400% chance of surviving compared to rubble (13:2.75=4.72). This seems wrong.

The total ineffectiveness, tactically speaking, of 105 artillery vs. troops INSIDE a building seems off. The buildings were 2x2, with 3 of them adjacent, creating a 2x6 with internal walls. One squad was in the north 2x2, one in the south 2x2, with the 7 man HQ and 2 man RPG element in the central 2x2. Hence, 9 men per 2x2. Each building was hit with 20-24 shells, fuzed GENERAL. The only protection the men had was the rooftop (walled). An assumption can be made that each 9 man group had 6 to 8 105 shells detonate directly overhead. Toss in a few longs or shorts; that leaves 4 to 6 105 shells MINIMUM impacting on top of them. Even point detonation should allow for some rooftop penetration.

My takeaway:

Do NOT lie down on pavement during an artillery strike.

Do, however, set up inside the top floor; you will be essentially immune to artillery.

Do setup units on rooftops if you need the LOS; odds are they will have enough survivors to be quite effective.

Thoughts?

[Lanzfeld]

Thanks for your work (and humor)!

My thoughts are a tweak is needed in both the "rooftop survivability" and "inside a building immunity to arty" but I am interested in the 81mm and 155mm tests if you do them.

Also...do you plan on looking at troops surviving abbuilding collapses and having the ability to keep fighting?

[RecceDG]

The Queen's Light Prancing Into Battle With Skirts Atwirling Royal Artillery

I love those guys!

DG

[sross112]

The Queen's Light Prancing Into Battle With Skirts Atwirling Royal Artillery

I love those guys!

I was just glad it wasn't the Queen's Heavy Cartwheeling Around the Battle Rocket Artillery.

[noxnoctum]

As someone who lived in a Muslim country for 6 years where all the buildings have flat roofs, I can assure you that there is no cover there whatsoever on 95% of the average homes. Unless you count laundry drying out on a rope .

So yes, this needs to be remedied. I'd say troops on rooftops should only gain a 10% advantage over troops in open ground/dirt, just to account for the rare house that does have some sort of small bit of cover (i.e. a giant satellite dish or something of that nature).

[Lanzfeld]

Still not going to stop the shrapnel from a 155mm but I get what you are saying.

[c3k]

I'd guess it'd depend on exactly HOW dirty that laundry is...

Ken

[dan/california]

So the game take away at the moment is you have to shell it to rubble, and then shell the rubble?

[Boche]

what I do and seems to work better with troops in buildings if they are at ground level, is shell the ground beside it. I discovered it during a PBEM where i shelled the lenght of a street i knew enemy units where garrisoned in. the barrage of 82mm caused tons of casualties and basically won the match for me. From then on i seem to get much better results if I use this tactic than shelling say the roof of the building.

[akd]

So the game take away at the moment is you have to shell it to rubble, and then shell the rubble?

The game takeaway is, as always, that it is best to nuke it from orbit just to be safe.

Seriously though, I'm pretty sure there is something more going on than rooftops offering a cover bonus. Quick test:

Blue dot is 105 air burst. Green dots are unwounded troops on the walled rooftop beneath the air burst. Red Xs are wounded/dead troops in trenches around the 1-story house caused by the same airburst, not including light wounds. Unit on the rooftop suffered no wounds whatsoever, only suppression.

Same situation, but "general" (impact) fuse:

Impact on roof causes multiple casaulties to unit on roof. No casualties, wounds to unit on first floor or units in surrounding trenches.

Further testing revealed that when troops on rooftops do take casualties from air bursts, it is more often than not from air bursts over ground adjacent to the building than over the roof itself.

This tower test further illustrates the above:

As you can see, the air burst occurring adjacent to the building but at a much lower height than the roof causes casualties on the roof.

[LukeFF]

As someone who lived in a Muslim country for 6 years where all the buildings have flat roofs, I can assure you that there is no cover there whatsoever on 95% of the average homes. Unless you count laundry drying out on a rope .

So yes, this needs to be remedied. I'd say troops on rooftops should only gain a 10% advantage over troops in open ground/dirt, just to account for the rare house that does have some sort of small bit of cover (i.e. a giant satellite dish or something of that nature).

As someone who's also lived in the Middle East, I can only agree.

[Chops]

C3K (a.k.a Ken) has presented his takeaways and provided metrics on the asks. By providing color on his resources, he has created vertical synergy. It appears that the powers-that-be are not on the same page, or else do not have their ducks in a row. Apparently they are not ready to open their kimono on this one. We all know Ken as a Team Player, and he really hit a home-run on this situation.

Hopefully BFC will touch base and provide some tic-tac on this by next week. BFC can you drill down on this issue and give us some deliverables? What will your ETA be on this one?

[Waaarg]

They JUST gave us 1.31. Not sure its fair to be asking for ETA on issues yet.

[Lanzfeld]

...and Chops....English next time please J/K

So for now it seems we should use general on rooftops and airburst for open ground.

[stoex]

Thanks for the test, c3k! Says it all, really. There is clearly an issue here that needs to be addressed.

[Erwin]

Very useful info. Thanks for doing the tests.

[bodkin]

I think protection on roof tops was increased in one of the patches because units were too vulnerable before to small arms fire when on a walled roof. While that was a nice change it also seems to have resulted in air burst artillery being ineffective.

The main problem for me at the moment is that many scenarios seem a bit broken as the scenario designers have given you arty to deal with identified threats in buildings yet this dosen't seem effective anymore making infantry assaults with the subsequent casualties necessary.

[vincere]

Tanks to C3k and AKD for tests.

Different AO but I found these photos of artillary damage to buldings interesting:

www.boston.com/bigpicture/2010/11/tension_in_the_koreas.html

About half way down iswhat looks like large shrapnel scrapes in the wall. TV ok though

[c3k]

Hopefully, no one read this yet. If you did, please excuse the results I just removed. Someone did not lock the stairwells to the rooftops, so our Syrian volunteers did not "understand" that they were meant to be up on the roof during the test. That misunderstanding has been rectified.

Testing continues apace!

[dan/california]

C3k, your thoroughness is matched only by your sense of humor. Granted they both imply...... something. But thanks none the less.

Steve, any chance of chiming in, even to tell us what complete **%^$#E#^@s we are?

What have c3k's poor pixeltruppen test subjects done to you?

Since the code already exist, obviously, you could even create a special fortified building type. But entire city blocks of them are a job for the B52s.

[c3k]

Right. Glad you've all made it back here for the summary on the rest of the test results.

We made a few tweaks to the testing grounds due to input from various sources, not least our staff psychologist, Dr. Intropy. Please stand. He suggested that we should allow the Syrian volunteers in the paved areas to have lower walls. He thought that giving them the ability to see over the walls would help them, as well as making the walls the same height as the rooftop walls. We therefore modified our Personnel Enclosure, New and created a modified PEN. Our concern that the low walls would allow "cold feet" and lead to, ah, fleeing, were mollified by the inclusion of alligator infested moats around all PENs. As well, Mr. Assad's representative spoke in private with each group of volunteers. In the end, our fears were groundless: every volunteer stood his ground! A big hand for them, please. None are here right now, the infirmary is ready to accept any thanks on their behalf.

The results with 155mm artillery, provided by the hearty lads of 1st of 5/4 Firth of Forths, are as follows: Linear, 32 meters, medium, medium, personnel. The tests were all stopped at 3 minutes, after approximately 14 shells impacted per target.

Syrian platoons of 27 men at start. The numbers represent the average number of survivors with the standard deviation after the slash.

- Infantry on walled rooftops: 9/3.2

- Infantry on paved ground: .1 (rounded up)/.3

In fact, only one volunteer survived the test on pavement! What a plucky lad! Dr. Intropy wanted to speak to him about what he ascribed his survival to, but the Syrian was a bit, ah, truculant at the time. Perhaps we can speak to him when he's feeling a bit more like himself.

We also ran the test with 81mm mortars. All the parameters were the same. Using medium/medium, each 2 tube battery fired 60 rounds. However, we also counted the results after just 24 rounds. The 24 round count provides apples to apples with the 105mm howitzer results, briefed earlier. The full 60 round count provides a comparison with the other medium/medium firing batteries.

24 Rounds:

- Infantry on rooftops: 21/2.3

- Infantry on pavement: 5.6/2.6

60 Rounds:

- Infantry on rooftops: 12/2.5

- Infantry on pavement: .5/.7

We're considering further tests with other ordnance, including 120mm and 60mm mortars, but the results we've gained to date merely strengthen our initial conclusions. The Syrian volunteers seem to think nothing will be gained by further testing, but Dr. Intropy is curious as to some other effects.

To wrap up tonight's presentation, I'd like to thank Colonel Mustard for the grand hospitality offered by his regiment's mess, the incomparable Devonshire and Corgi Yoemanry and Animal Husbandry.

Thank you.

[c3k]

An addendum in yellow highlighter.

The 155 results are interesting. Each target was essentially 3 adjacent 8x8 meter squares. Each target had approximately 14 rounds fired at it. Let's throw away 2 of those rounds for whatever reason you'd like. We now have 12 rounds distributed amongst 3 squares. Let's say that averages to 4 rounds per square.

We are left with 4 airbursting 155mm rounds for each 25 foot by 25 foot zone. Looking around the room I'm in, I'm hard-pressed to imagine ANY way of surviving in fighting shape even 1 airburst 155. Sure, some shrapnel or fragments may miss. Maybe I found an old tin bucket or pile of bricks which also shielded me from the overpressure. But what about the OTHER 3? Not to mention the rounds which are exploding ADJACENT to my little 25 foot square patch. The game allows a 1 in 3 chance of surviving in fighting condition in this circumstance (9 survivors out of 27 at start.).

Here's a Youtube link:

It shows the XM982 guided 155 round impacting a test target. Ignore the accuracy for which the XM982 was developed. The fuzing and fill is essentially the same as unguided 155 rounds. Notice the shrapnel and overpressure pattern. Notice the ability of the fragments to penetrate.

In a similar vein, looking at the 81mm results, we have 60 rounds impacting along a 100 foot line. That's about a round every foot and a half. Some will be long, some short. Let's throw away a quarter of them. We're left with 45 rounds. That's about 1 round every 2 feet. The survival percentage on rooftops is 44% (some lightly wounded). That compares with essentially no survivors on pavement. (Remember, red or brown is considered not to have survived. Green and yellow is okay.)

I ran 15 to 20 iterations to gain these numbers.

BF.C?

[dan/california]

C3k, If you have one more round of testing in you, could run at least the 155 against actual bunkers. I am very curious if even purpose built defensive works fare as well as the roof tops do currently. I apologize in advance to the pixeltruppen involved. The CMX2 community would like to thank the Syrian Mukabarat for their devotion to creating a realistic simulation, and reducing the crowding in their oversubscribed facilities.

[c3k]

You're pushing, lad, you're pushing it.

Fortunately, our Syrians tell me they're cracking to give it a go. Just wait a bit while we build some bunkers...

A quick result after less than 1 minute of firing: It is FAR safer to be inside a building on the topmost floor than to be inside a bunker.

More later...

Ken

[Martin Krejcirik]

Thanks for the tests, I've had the same feelings about ineffective artillery since the release of CMSF.