demolishing buildings, wirbelwind vs StuH

[CMplayer]

(sorry if this has been discussed

to death before)

I've recently played a number of games

defending as allied airborne, in towns,

against German combined arms attacks.

Typically, my opponents chose StuH's, and

employed their 105mm to try bring as many

buildings down as possible.

This is a poor choice if looked at just

from the point of view of demolition

power.

This test was to compare the abilities

of the StuH and the Wirbelwind at

demolishing large heavy buildings.

The vehicles were purchased with

standard ammo load and were regular

quality.

Two rows of heavy buildings are set

up, one for the WW and one for the Stuh.

The frontmost building in each line

is area-fired, targetting the center

of the upper-story facade. No rounds

missed their targets.

When a building was brought down, the

next building behind it was targetted,

(LOS only being possible because of

the collapse of the previous building)

The WW consistently brought down large

heavy buildings after 2 minutes and

5 seconds. The StuH required 2 minutes

and 30 seconds to do the same job.

The big difference however is in the

total amount of work done. The StuH's

ammo was enough to demolish 2 buildings

and reduce 1 to ** level.

The WW reduced 4 buildings to rubble,

set two on fire(one of which was already

at **) and reduced a seventh to ** status.

(it had to move, to get LOS to targets

behind burning buildings)

So the StuH, at a cost of around 78 pts,

made 3 buildings inhospitable for infantry,

while the WW, at about 105 pts, did the

same, faster, to 7 buildings, more than

twice as many, for less than half again

the cost.

Does this reflect how these vehicles

would perform in real life? It seems

backwards to me, but I have no personal

experience by which to judge.

thx,

--Rett

[gunnergoz]

I can't see either vehicle you mention used in it's historic role as a block-buster, except perhaps in some isolated incident.

The exorbitant amount of ammo expended would simply not be permitted under field circumstances. There are more economical ways to level buildings (bombers for one) and most of the time it's not necessary if one simply wants to eradicate the defenders.

The rubble produced might actually benefit the defenders (remember Monte Cassino) and hinder the attacker's manouverability (St. Lo or Stalingrad).

Leveling buildings by firepower was done, certainly, just look at the Soviet films of 203mm tracked howitzers being used in Berlin over open sights...You can bet that flattened the building all right! But that was an example of intensive inner-city fighting that CM doesn't lend itself well to.

Historically, the best vehicles for the job if it indeed had to be done, would be the engineer tanks (Churchill spigot for instance) or the soon-to-be-seen sturmpanzer or sturmmorser tiger and the SU-122 and -152.

[Panzer Leader]

Well, putting aside the "historical" inplications for a moment, what is the difference between 2:05 and 2:30 when the tank will continue to area fire at the rubble for the duration of the turn even after it falls?

[ 06-26-2001: Message edited by: Panzer Leader ]

[Col Deadmarsh]

Forget about that, what about the fact that you get better armor with the Stug than the Wirble. That should equal everything out.

P.S.--I'd like to request a comparison between the Wirble and the Ostwind. With a 37mm gun, and about the same points, it seems the Ostwind would always be the way to go.

[Guest Babra]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Panzer Leader:

Well, putting aside the "historical" inplications for a moment, what is the difference between 2:05 and 2:30 when the tank will continue to area fire at the rubble for the duration of the turn even after it falls?<HR></BLOCKQUOTE>

:confused: That was changed for version 1.12

[Panzer Leader]

It was? Oh ****! Lemme check something real quick...

No I'm good. Maybe I was just remembering it from before or something. Though it seems like it happened recently...

[ 06-26-2001: Message edited by: Panzer Leader ]

[Ron]

AFAIK there is some randomness to how quickly buildings collapse.

In a couple instances with 1.12 I have seen assault guns continue area firing after the building was demolished, but I wasn't paying attention to the circumstances to comment further. (shrug)

Ron

[KiwiJoe]

They will continue to area fire if they think there are unit(s) in the rubble. If not they will stop.

[CMplayer]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Colonel_Deadmarsh:

Forget about that, what about the fact that you get better armor with the Stug than the Wirble. That should equal everything out.

P.S.--I'd like to request a comparison between the Wirble and the Ostwind. With a 37mm gun, and about the same points, it seems the Ostwind would always be the way to go.<HR></BLOCKQUOTE>

Ask and ye shall receive.

The Ostwind was just a little bit slower

than the Wirble at taking down buildings

in the new test. Both flak vehicles knocked

down a total of 5 buildings with their

ammo. The OW reduced the sixth to **, the

WW its sixth to *.

I also threw in a mark IV. It reduced one

building to rubble and made ** of the second.

regards,

--Rett

[CMplayer]

<BLOCKQUOTE>quote:</font><HR>Originally posted by gunnergoz:

I can't see either vehicle you mention used in it's historic role as a block-buster, except perhaps in some isolated incident.

<HR></BLOCKQUOTE>

Interesting post. My question, for you

and anyone else is, are these results

a realistic performance for these vehicles?

I just can't picture 20mm cannons doing

that kind of structural damage to large

stone apartment buildings in such a short

time, not even if you take into account

the 'time compression' of CMBO.

thx,

--Rett

[ 06-27-2001: Message edited by: CMplayer ]

[Stacheldraht]

Don't forget, too, that compared to the Wirbelwind, the Ostwind has more ammo, slightly better armor, and slightly better armor penetration with its AP rounds. It costs the same as the Wirbelwind. All told, the Ostwind is an extremely effective weapon in CM.

[CMplayer]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Stacheldraht:

Don't forget, too, that compared to the Wirbelwind, the Ostwind has more ammo, slightly better armor, and slightly better armor penetration with its AP rounds. It costs the same as the Wirbelwind. All told, the Ostwind is an extremely effective weapon in CM.<HR></BLOCKQUOTE>

Agree it's a very good vehicle in CM, but

it's not always available.

I still think that the building destruction

abilities of these flak vehicles are

a quirky, unrealistic, gamey result of

poor algorithms.

--Rett

[Stacheldraht]

You're probably right, but I'd like to see empirical real-world data before reaching conclusions. Not that I expect that will be easy to come by in this case

[CMplayer]

JasonC recently wrote: <BLOCKQUOTE>quote:</font><HR>

Buildings go down ridiculously fast in CM. You can still fight in the rubble of course, but it does not have any elevation/second story. This makes direct fire HE way too effective against building cover.

Urban fighting did produce streets of rubble, but not from light cannon, or even tank guns firing a few scores of shells. They were rubbled by air bombardment in the hundreds of tons of bombs, or artillery fire kept up over days or weeks and running in some cases over a million shells fired.

If one imagines some very light shacks for which the rate of destruction in CM seems realistic (e.g. for a one story wood building perhaps), then the question becomes, where are the more serious buildings?

You know, the air forces went to the trouble of making bombs of several thousand pounds for a reason - because bombs up to 250 or even 500 lbs just did not level city blocks. Up to half the weight of a large air-dropped bomb can be explosive.

The TNT in a tank round is 1-2 lbs, and in light guns rounds (20mm etc) it is measured in grams. Engineers used 5-10 lb bags of TNT to blow holes in brick walls large enough for a man to fit through. The size of explosive charges that bring down the fronts - but not all - of large buildings in terrorist attacks, run into the hundreds and sometimes a few thousand pounds.

A few 1-2 lb HE charges are not going to bring down a 2-4 story brick or concrete building, even if you planted them on supports, which tank fire through a wall does not do.

CM seems to use a cumulative total HE charge received measure to collapse buildings. A more accurate way would add up something like the square of the blast, to make small rounds largely irrelevant and the largest ones the only ones likely to result in collapse. They should be far more robust against blast ratings under 50 or so, and somewhat more robust (especially larger and heavy building types) against even the big shells.

<HR></BLOCKQUOTE>undefined

[Stacheldraht]

What's needed is the expert opinion of a demolitions expert, combat engineer, and/or contractor who knows about structural strength and support. (I don't mean to sound flippant; I'm genuinely curious.)

[Silvio Manuel]

Hmmmm, those German flak tracks were super rare too. Something like:

Wirblewind:86

Ostwind: 36

vs.

Super Pershing: 25

in #'s that were produced.

[offtaskagain]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Silvio Manuel:

Hmmmm, those German flak tracks were super rare too. Something like:

Wirblewind:86

Ostwind: 36

vs.

Super Pershing: 25

in #'s that were produced.<HR></BLOCKQUOTE>

I couldve sworn only 1 or 2 Supers were built.

[Claymore]

Qualifications:

Physicist with 10 years of direct experience in the fields of explosives and counterterrorism. Not exclusive experience mind you...but a constant supply of funds which come my way to do...ah..well...something. I've worked with the FAA, FBI, and Navy SEALs on the what, where and how of things that go BOOM.

Opinion:

The destruction of ANY building type by DF HE < 105mm is completely inaccurate in CMBO. Whether it be a LIGHT or HEAVY building you are not going to blow out the supporting framework nor comprimise the stability by using these lightweight rounds. You will make life VERY uncomfortable for anyone caught inside them but the building will remain standing. There is a much higher risk of fire than currently modeled in CMBO however, especially from the AA rounds. The multipoint impacts of HE/HEI/Tracer rounds inside a structure packed with combustables have a much greater chance of starting fires than is currently modeled. A SWAG you ask? Ok...about three times more likely.

The destruction of SMALL LIGHT buildings by DF HE >= 105mm is adequately modeled in CMBO. A small wooden 2 story home submitted to 2-3min of 105mm DF fire is going to be on the rickety edge of collapse. Obviously as the caliber increases the models excursion from reality drops.

The destruction of SMALL HEAVY buildings by DF HE >= 150mm is adequately modeled in CMBO. In reality the stone farmhouses of Northern France became ad hoc pillboxes for whoever occupied them. The reduction of these strongpoints was NOT performed by leveling the structure using DF HE. If a close assault by troops was not feasible then AP rounds were fired until a hole was made, unless a suitable window presented itself. Then HE would be fired through the breach, and the concussive and explosive effects more than sufficient to persuade the defenders to move on. CMBO uses an abstraction of BLAST effects and cover/concealment bonuses for housed infantry.

Q: Do housed infantry receive the cover/concealment bonus when a round detonates inside a structure?

In general there should be no real difference between infantry having a round detonate nearby while inside a HEAVY or LIGHT building, interior walls being made of the same soft woods construction materials.

There is room for argument and debate here as to the historial use of DF HE from tanks. Was the majority fused as super quick or with a delay? From my examination of historical photos I see a lot of blast patterns from point detonating rounds on the sides of buildings.

The destruction of LARGE LIGHT, LARGE HEAVY, and most especially CHURCHs is not in any way handled correctly by CMBO. In the case of a 4 story box structure composed of a light wooden structural framework you need to supply the equivalent of 15kg of TNT in order to drop the building. This SINGULAR charge also needs to be placed quite accurately otherwise the amount of explosives roughly increases as square of the distance. Punching 500m/s DF through these buildings and expecting a cumulative effect in BLAST damage is really beyond the pale.

Again...I'll say that the chances for sparking ignition inside these buildings is very much under represented in CMBO. Anyone who has seen a round detonate will attest as to its pyrotechnic potency.

now...my last opinion.

It is certainly better than anything else I've seen in the wargames arena. There are far more things which require attention than this. Play on!

cheers

Murray

[ 06-27-2001: Message edited by: Claymore ]

[CMplayer]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Claymore:

Again...I'll say that the chances for sparking ignition inside these buildings is very much under represented in CMBO. Anyone who has seen a round detonate will attest as to its pyrotechnic potency.

<HR></BLOCKQUOTE>

Buildings in CM that do catch on fire

are engulfed in flames instantly and

everyone runs out. You could increase

the odds of them catching fire, if you

had the fires start out small and leave

the squads inside a couple of turns

to get out in good order before the

TAC AI runs them out into the wrong

street to be chewed up.

Just an idea, otherwise, thx for an

interesting post.

--Rett

[Enoch]

Thanks, a most informative post that helps to clarify some things. So CM makes destruction of bulidings easier while buildings going up in flames is more rare. The end result is almost the same though. The building is not usable. The major difference between a building on fire and collapsed obviously is that the collapsed building does not blocl LOS behind it while the burning building does.

Perhaps something that BTS can fix in future incarnations of CM.

Thanks again, Murray.

[engy]

However, there is the case of 2 Tigers sitting on the brige at Arnhem (Market-Garden) which were given the orders to shell the houses above the British paras 'floor by floor until the houses drop on their heads.' IIRC they were very successful and kept the British hopping from building to building to escape imminent collapse and a significant portion of Arnhem along along the riverbank was reduced to rubble.

Unfortunately, I have no idea what those houses were made from, but I seem to recall that they were 4 stories or so, which would make them either a CM "Tall Light Building" or a "Tall Heavy Building" (but, from the pictures I remember, they are taller and thinner in proportion than the CM Tall Heavy Building).

I ran 2 quick tests:

I. Tiger v. Tall Light Building

Results:

1. Tiger expends 8 rounds of HE

2. Total time to building collapse: 1 min, 38 secs.

II. I. Tiger v. Tall Heavy Building

Results:

1. Tiger expends 16 rounds of HE

2. Total time to building collapse: 2 min, 58 secs.

My comments:

1. If the anecdotes from Market-Garden are true, the Germans did use 88mm Direct Fire HE to bring down buildings.

2. The time to bring down the buildings seems a little quick, but on the other hand, the "Tall Heavy Building" took nearly half of the HE load of the Tiger.

I'm throwing this out there as food for thought...any comments?

Edited for formatting/spelling mistakes, and to add my comment on the proportions of the CM Tall Heavy Building.

[ 06-27-2001: Message edited by: engy ]

[Lars]

You beat me to it Claymore. Keep in mind these buildings weren’t built to modern codes. Modern buildings are built as light and as cheap as possible, not to last forever. The Church and Large Stone building in CM probably represent a building that’s been around for a few hundred years. They were over-engineered for their purpose due to the material being used and would be very tough to bring down. The frequency of fire should be boosted greatly in all of the buildings due to type of insulation, roofing materials, and heating fuel sources that may be near. These buildings would combust long before they collapsed.

However, I love it when they blow up.

[JasonC]

On production of German Flak vehicles, the Ostwind proper and the Whirblewind were indeed both rare. 87 Ws and 81 Os were made. But there were another 240 37mm AA tanks like the Ostwind, just with a different turret and gun (the FlaK36(Sf) auf FlakPzIV). There were also 142 single 20mm FlaK mounted on Czech chassis as light AA tanks. All told that is 550 Flak tanks.

The haltrack versions of all three (single 20, quad 20, and 37) were more common, with 610, 319, and 462 of them produced. All told that is ~1400 Flak halftracks.

Thus the whole category was about as rare as Tiger tanks, with halftrack versions about as common as Tiger Is and tank versions about as common as King Tigers. Of course, they were doled out in platoons, pairs, or single vehicles, rather than ~45 at a pop, so more formations had them. And 3/8th of them were only single 20mm mounts, not the better, heavier pieces represented in CM.

[ 06-27-2001: Message edited by: JasonC ]

[Stalin's Organ]

Jason what about the triple 15mm 251's?