Artillery Test vs. Rooftop troops, v1.31

[c3k]

I don't believe this is the case, but there is a heavy element of dice rolling involved that clouds this issue. I went into detail in the other thread on the apparent random nature of roof/floor penetration by artillery. The same seems to apply to bunkers, so there is always a given chance that in comparing 10 rounds versus a building and 10 versus a bunker, one test might have the building occupants safe and the bunker occupants all dead, the next might have the opposite...

akd,

You're absolutely correct about the die-rolling nature. The test results I posted were all repeated dozens of times. The exception, as noted, was my quick bunker test. In that case, 6 bunkers and 6 buildings were targeted. The effectiveness of artillery vs. bunkers opposed to the ineffectiveness of artillery vs troops on the top floor was so pronounced that I posted the preliminary results. I will, next week, run many iterations of that test and post the results.

Ken

[c3k]

Similar observations (and responses) from a year ago:

http://battlefront.com/community/showthread.php?t=89370

[BlackMoria]

Fuzing: today's world of high-tech microchips makes fuzing a lot easier than before. I think we can all agree that's true. The old calibrated powder-filled straw sticking out of a mortar shell is a thing of the past. But even those old-timers were able, with enough time and shells, to get shells to burst where they wanted. Sometimes.

Fuzing to penetrate a single rooftop is far easier than I believe you're alluding. I am NOT an artilleryman. My military background is USAF. All I know about artillery fuzing is from staying at a Holiday Inn Express. However...

Most shells are heard as they fall. They are subsonic. The speed of sound is very roughly 1,000 feet per second. A 1 millisecond delay on a superquick fuze equates to bursting 1 foot after fuze activation (ignoring deceleration due to resistance from whatever activated the fuze). Figure a 10 foot value per floor (including roof/subfloor, etc.), that means you're looking for a 10 millisecond delay after hitting the roof to explode near the floor level of the top floor. Make it 5 milliseconds if you want to explode at chest height. Add 10 milliseconds for each subsequent floor you wish to penetrate.

The above is posted with no practical knowledge. I'm sure artillery units KNOW the velocity the shells come down, depending on trajectory. I'm sure they have fuzing tables to penetrate common objects.

WWII era shells had fairly complex, accurate, fuzable shells. The old fuze key springs to mind. Does anyone know what the calibration markings were timed to? (They were in milliseconds.)

I do not believe modern artillery should face significant issues in penetrating rooftops, no in fuzing the shells to detonate after the penetration.

Am I way off?

Ken

Artillery guy here. I served 17 years with the guns but I have been out of the service for 15 years how.

Standard HE rounds have a quick setting (fuse initiates when X lbs of pressure on the fuze) and a delay setting. The delay setting is 1/2 second delay after the same pressure. The delay setting is not more time selectable than that.

Time fuses can be set to 90 seconds in 1/10th of a second increments but this is the key, the round explodes on impact like a standard fuse on quick setting. The reason is the purpose of the fuse, which is to initiate the exploding of the round along the trajectory, not how long after it hits the ground.

Variable Time fuses emit a radio signal and looks for a echo return of that signal reflected off the ground. The fuse is designed for a optimal height of 7 meters above the ground but the type of soil affecting the reflectivity of the radio signal will vary this up or down by several meters.

At the time I was in, there was no fuse (at least that I saw in my career) that was designed specifically for variable initiation after penetrating the ground. There may be now so I can't comment on that type of fuse.

As a observer who called in fire and has seen the effect of artillery fire on all sorts of things, I will make some comments.

A 155mm round on delay fuse will penetrate 24 inches of overhead cover consistently. The bench mark of 24 inches of overhead cover is a layer of 2X4 wood, covered by two layers of metal revetment, covered by sandbags of dirt to a depth of 24 inches - standard bunker and hard point prepared structures in a defensive position.

A 155 round on delay fuze will penetrate 3-4 floors easily of as standard western style wood framed house (inter level floors are wood 2x6 trusses with 2 layers of 3/4 plywood) and will very quickly compromise the structure of the house.

A 155 round on delay will only penetrate 1 floor of a standard concrete building, where the floors typically are 12-18 inches of concrete with rebar. The structure will hold up for while but eventually, the explosive overpressures of 155 rounds will crack and rubble the concrete to a gravel and the building will come apart.

I am not certain how middle east structures compare but my opinion is that a 155 round on fuse delay will consistently penetrate at least one level of the structure as a minimum. I am less certain about mortars and 105 rounds, for while I have seen the effects of those first hand, I spent my career with 155mm gun batteries, so I will speak of only what I know for certain.

For what it is worth to this discussion.

[dan/california]

Thanks for checking in, Black Moria. Do you have any opinion on how much it matters if the masonry structure of a building is of less than sterling quality? I don't think most middle eastern building inspectors are overly picky, except about that little envelope.

[c3k]

Artillery guy here. I served 17 years with the guns but I have been out of the service for 15 years how.

Standard HE rounds have a quick setting (fuse initiates when X lbs of pressure on the fuze) and a delay setting. The delay setting is 1/2 second delay after the same pressure. The delay setting is not more time selectable than that.

Time fuses can be set to 90 seconds in 1/10th of a second increments but this is the key, the round explodes on impact like a standard fuse on quick setting. The reason is the purpose of the fuse, which is to initiate the exploding of the round along the trajectory, not how long after it hits the ground.

Variable Time fuses emit a radio signal and looks for a echo return of that signal reflected off the ground. The fuse is designed for a optimal height of 7 meters above the ground but the type of soil affecting the reflectivity of the radio signal will vary this up or down by several meters.

At the time I was in, there was no fuse (at least that I saw in my career) that was designed specifically for variable initiation after penetrating the ground. There may be now so I can't comment on that type of fuse.

As a observer who called in fire and has seen the effect of artillery fire on all sorts of things, I will make some comments.

A 155mm round on delay fuse will penetrate 24 inches of overhead cover consistently. The bench mark of 24 inches of overhead cover is a layer of 2X4 wood, covered by two layers of metal revetment, covered by sandbags of dirt to a depth of 24 inches - standard bunker and hard point prepared structures in a defensive position.

A 155 round on delay fuze will penetrate 3-4 floors easily of as standard western style wood framed house (inter level floors are wood 2x6 trusses with 2 layers of 3/4 plywood) and will very quickly compromise the structure of the house.

A 155 round on delay will only penetrate 1 floor of a standard concrete building, where the floors typically are 12-18 inches of concrete with rebar. The structure will hold up for while but eventually, the explosive overpressures of 155 rounds will crack and rubble the concrete to a gravel and the building will come apart.

I am not certain how middle east structures compare but my opinion is that a 155 round on fuse delay will consistently penetrate at least one level of the structure as a minimum. I am less certain about mortars and 105 rounds, for while I have seen the effects of those first hand, I spent my career with 155mm gun batteries, so I will speak of only what I know for certain.

For what it is worth to this discussion.

I think it is worth more than the sum total so far.

Thank you very much for posting your relevant experience and observations!

Ken

[BlackMoria]

I have seen a small (about 25ft x 25ft) single story wood structure constructed to western building standards blown down to floor level - ( ie. no ceiling or walls left) by a single 155 round.

I think a middle east house of similar dimensions made of earthen brick work that would be insufficent by western construction standards will not fair any better. It is not the brick but the mortar between the bricks that is the weak point and would be the point of failure. I think the overpressure from a 155 round direct hit on that structure is going to level it after a round or two, making a scattered field of bricks.

Let's put it this way - if I had a choice of taking cover in a ditch or taking cover in that structure, I would opt for the ditch...

[akd]

I have seen a single 155mm hit (i.e. the first shot, no other hits or adjacent misses) take out the roof a CMSF 1-grid, 1-story building. But since the effects of a hit to the roof do not extend to underlying levels, the only way to know if a single penetrating hit from 155 had a chance to take out the whole structure, would be to observe a string of first-round penetrations. This is very difficult to achieve for the reason above.

[dan/california]

I have seen a small (about 25ft x 25ft) single story wood structure constructed to western building standards blown down to floor level - ( ie. no ceiling or walls left) by a single 155 round.

I think a middle east house of similar dimensions made of earthen brick work that would be insufficent by western construction standards will not fair any better. It is not the brick but the mortar between the bricks that is the weak point and would be the point of failure. I think the overpressure from a 155 round direct hit on that structure is going to level it after a round or two, making a scattered field of bricks.

Let's put it this way - if I had a choice of taking cover in a ditch or taking cover in that structure, I would opt for the ditch...

Thanks for the additional info. In terms of relative protection levels in the game does anyone else think that ditches/trenches are weak compared to buildings? We might as well pulverize the rest of this poor horse while we are at it.

[c3k]

Here's a link with more on modern fuzes:

http://www.pica.army.mil/picatinnypublic/products_services/products19.asp

That's just one company's product line. It seems that artillery CAN be used to penetrate structures.

One word: Normandy, thatched roof.

(Thanks to those who have clarified my understanding of fuzes.)

[Battlefront.com]

Update from our end... Charles did identify a problem and he has made some adjustments. We're testing it in Normandy with the next build for testers and then, once it's been tweaked, it will go into CM:SF and CM:A patches.

Thanks for doing the legwork on this. We're up to our eyeballs in Bocage these days

Steve

[dan/california]

Thanks Steve, We can't wait for Normandy. Well we we will, but.........

[c3k]

Thank you!

Ken

(Waiting for plunging shells to meet thatched roofs in Normandy!)

[gibsonm]

Ah so don't worry about fixing it for slate ones?

[Chad Harrison]

We're up to our eyeballs in Bocage these days

Steve

I am having a hard time picturing what that would look like. Perhaps you can help Steve?

[Hairy Pie]

Has anyone done any tests against infantry in trenches? From playing some of the Brit scenario's recently, I'm sure they are much tougher to kill with airbursts now than they used to be, even after multiple barrages. Might be imagining it though!

[akd]

No, they die quick in trenches. See my earlier tests with the house surrounded by trenches.

[LongLeftFlank]

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 .

Depends on the vintage of building and its use -- It is true that post 1990 vintage homes in the wealthy Gulf states (I was in the UAE 2 days ago and took note of this) tend not to put much up on the roof other than sat dishes. On the other hand, most pre-1990 multistory buildings, including single family homes, have a cinderblock stairwell enclosure (about the size of a handicapped port-a-john) on the roof that will offer some cover from shrapnel. And most post-1980 office buildings typically have HVAC package equipment and/or elevator mechanical equipment on the roofs, in sheds to protect them from the elements -- residences and apartments mostly use window or wall units instead. Poorer families who can't afford AC will often sleep on the roof on especially hot, still nights.

I just returned from a monthlong trip to South Asia, including the Emirates. I realized that emergency diesel backup generators (and their fuel tanks!) are ubiquitous flavour objects missing from the game (think an immobile soft "vehicle" that can be readily set afire), not that I expect them to appear at this point. But it's nice to dream.

[vincere]

We're looking into it for v1.32. I'll let you know the results of internal testing as soon as I have 'em. Thanks!

Steve

Any news on th eroof top phenomenom?

Check out USMC style: www.wired.com/dangerroom/2011/01/25-tons-of-bombs-wipes-afghan-town-off-the-map/

[gibsonm]

Nope!

In the same category as the Panzerfaust issue - i.e. everyone busy working on CM:BN at present.

[vincere]

Knee jerk response was WTF, it's been some time.

But hey let's hope they get as much tweaking and a fixin and any squeezin in as possible.

And also push that NW Europe baby out the door soon too

edited- serioursly, thanks for letting us know. Seriously got enough to having fun with still messing with the yanks.

edited 2. anyway, if you look very closely you can see a couple of yellow injured soldiers hunkered down and a whole platoon still green amongst the rubble.

[gibsonm]

Well when “everybody“ = roughly 2, in terms of people doing coding, you start to get the idea.

So they focus on main effort and are making progress there, rather than work on Project A, stop re orientate (remember where things are up to and how its structured) to Project B dabble there then shift back to Project A again.

End result either one Project done reasonably quickly or both projects take a very, very long time.

Not too worried about the edits as I didn’t look.

[vincere]

Not too worried about the edits as I didn’t look.

He he, no worries mucker, I wasn't deleting any end of week spill overe from work loonatics. Just edited to balance add some balance that personally I'm not in a major rush and add some trite humour about survivors from the pounding.

(Note to self regarding humour- don't give up my day job.)