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Question about BK-31 Heat-FS-T [FIXED]


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Using Colebrooks "test-of-26.sce" scenario from this post:

I was able to reliably reproduce the OF-26 round being extremely lethal. Then I put Leo2A6's in instead of T-72s and M1A2s instead of Leo2Es and found the DM11 to be just as problematic.

 

Here is an M1A2 killed with a DM11 hit directly on the turret armor:

 

0zeFqro.jpg

 

I suspect the problem is indicated by the "RHA strength of fragments" indicator which says 6-67mm. 6.7cm of penetration for the fragments seems a bit excessive against armor.

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No, the M1 is perfectly able to withstand 67mm fragments in areas that would kill it in all those areas of impact. If it was under the side skirt then that would be another story, but that is a vulnerable place on any tank (and is one reason why they have skirts).

 

Of course even with the fix, there would still be situations where some fragments could be lethal to some vehicles, like perhaps an aircraft bomb or 155mm artillery round, or some HE and HEAT rounds versus light and non-armor, but that would be correct.

 

The issue is actually when you go to the next "HE Explosion" sub event, the arrow.  If it says destroyed (overpressure) then this is the problem, so its easy to see the issue. Fragment kills (although non-existent in  these situations) is a nice new correct behavior, but its the over pressure kills on tanks by these rounds which are the issue.

 

Tank overpressure kills via aircraft bombs, very large/huge IEDs, hits by 155mm HE, FAE warheads are all fine though.

 

I am just trying to establish what is normal and expected, and what is not - since I know how prone everyone can be to panic attacks. 😑

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Ah, well, we did notice that it seems to show up most of the time but there are occasions where it doesn't happen. If you didn't see it there, then you will likely see it on other events.

 

As mentioned a while ago, the lethality is known now, thanks to this thread. This existed in "old HE" in 4.0, and we thought we addressed it entirely, but apparently it still remains.  Also described earlier is that the tests do not show that this happens reliably.  In tests it too 50 to 100 rounds, several different times, to get a kill. Its based on random numbers, die rolls. Some people can apparently see it reliably.

 

In any case, this has been/is addressed. Fixed. 

 

(With that in mind, and with all the time I have spent in this thread, I am officially moving on to other work, as this is now beating a dead horse).

 

 

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The question is , how often does it occur. Steel Beasts uses an energy and chance based system. If it happens once in 20 shots or once in 100 cases, the lesson to take home is that it requires a lot of luck to be successful (or, on the other end, "most of the time" you'll be safe).

If this happens all the time: Problem.

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To answer your original question explicitly, I think it's a case of overpressure, although that cannot be assessed with certainty from a single case & single screenshot. If you shoot an M1 twenty times with that round in the same location and then tell me in how many cases you had the M1 killed I might be more confident to answer which mechanism is responsible. If it happens in 0...2 cases out of 20, I'd say that nothing's wrong. 1 out of 20 is what can be expected, approximately, but since randomness is involved, one more or less is always possible in a sample size of 20.

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2 minutes ago, Ssnake said:

Are these isolated incidents, or does it happen all the time?

This is the question of pivotal importance.

From initial low number test...every 8th round produces kill where it should not...

 

Might be overpreasure related/...or some "holes" in the armour model where the shrapnell fit trough

Edited by Grenny
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OK, let me explain some things to be clear, since this is bubbling up again, and I don't think everyone understands the issue...

 

From a mathematical point of view, the issue was fixed ***in the "new HE" behavior*** (this is an important distinction, see below). This is why the thread was marked fixed.  Beyond that, there might be a lingering bug in "new HE" behavior, sure - this is always a possibility, but right now it doesn't look like it without more information (see below about this too).

 

But the issue involves a great number of aspects (its a complicated issue), and it cannot be investigated simply with "drive by" posts or AAR screen shots.  As has been stated, for any sort of serious investigation to occur, there must be the following provided:

 

1. A test scenario.

2. Some AAR images showing where to aim.

3. In the AAR, is the destroyed result recorded as overpressure? (you have to scroll through the sub events to know)  This is very important because it differentiates between whether this is overpressure or "old HE" behavior (see below).

4. A statement about how many average shots it takes to kill the vehicle in that impact. An example would be like this:  'In test 1, I fired 30 rounds and one of them killed the vehicle, and then in test 2, I fired 20 rounds and one of them killed the vehicle, and test 3, it was 10 rounds.'  The average then is 20 rounds/impacts for a kill.

 

Why is it important to know the average number of rounds to cause the kill? Its important to check the math, and any other theories. Otherwise, just a one off test, is not useful, because its like rolling a die of an unknown number of sides, and getting a "1". It can happen in the first roll, but it doesn't give a hint to how probable it is.

 

We don't have the resources to take two or three people and have them devote a day or week to investigating, based on screen shots and vague posts.

 

And now for the most important part to understand the current situation:

 

There are still some old pre-4.1 behaviors hanging around and we are fully aware of them (I thought I explained this previously, but maybe not). Let's call the pre-4.1 behavior as "old HE", and "old HE" had splash damage and impact damage. The splash damage (the proximity hits on the ground and in trees) have been removed, but what still remains is the direct impact damages, and YES, this sometimes this can result in a kill, and it is unrelated to overpressure issue originally reported here.  This "old HE" behavior is ***no different than how it has always performed*** which means that there were certainly cases where you could get a kill from HE on a tank, in all the versions before 4.1 (all the way back to version 2.0, at least).  However, to prove that theory correct, I need #1-4 above to investigate it.  For this "old HE" behavior, it is going to take time to fully eliminate it from the engine, because it is embedded in just about everything, but we have been working on doing that, and so until that happens HE rounds will continue to have a chance to kill tanks like they always have.

 

So, long story short:

 

It could be a bug (and #1-4 above will help determine this), or it could be the typical case where a new update comes out, and New HE draws attention to something that always existed (old HE kills).

 

But without more information provided, we will never know.

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10 hours ago, Volcano said:

OK, let me explain some things to be clear, since this is bubbling up again, and I don't think everyone understands the issue...

 

From a mathematical point of view, the issue was fixed ***in the "new HE" behavior*** (this is an important distinction, see below). This is why the thread was marked fixed.  Beyond that, there might be a lingering bug in "new HE" behavior, sure - this is always a possibility, but right now it doesn't look like it without more information (see below about this too).

 

But the issue involves a great number of aspects (its a complicated issue), and it cannot be investigated simply with "drive by" posts or AAR screen shots.  As has been stated, for any sort of serious investigation to occur, there must be the following provided:

 

1. A test scenario.

2. Some AAR images showing where to aim.

3. In the AAR, is the destroyed result recorded as overpressure? (you have to scroll through the sub events to know)  This is very important because it differentiates between whether this is overpressure or "old HE" behavior (see below).

4. A statement about how many average shots it takes to kill the vehicle in that impact. An example would be like this:  'In test 1, I fired 30 rounds and one of them killed the vehicle, and then in test 2, I fired 20 rounds and one of them killed the vehicle, and test 3, it was 10 rounds.'  The average then is 20 rounds/impacts for a kill.

 

Why is it important to know the average number of rounds to cause the kill? Its important to check the math, and any other theories. Otherwise, just a one off test, is not useful, because its like rolling a die of an unknown number of sides, and getting a "1". It can happen in the first roll, but it doesn't give a hint to how probable it is.

 

We don't have the resources to take two or three people and have them devote a day or week to investigating, based on screen shots and vague posts.

 

And now for the most important part to understand the current situation:

 

There are still some old pre-4.1 behaviors hanging around and we are fully aware of them (I thought I explained this previously, but maybe not). Let's call the pre-4.1 behavior as "old HE", and "old HE" had splash damage and impact damage. The splash damage (the proximity hits on the ground and in trees) have been removed, but what still remains is the direct impact damages, and YES, this sometimes this can result in a kill, and it is unrelated to overpressure issue originally reported here.  This "old HE" behavior is ***no different than how it has always performed*** which means that there were certainly cases where you could get a kill from HE on a tank, in all the versions before 4.1 (all the way back to version 2.0, at least).  However, to prove that theory correct, I need #1-4 above to investigate it.  For this "old HE" behavior, it is going to take time to fully eliminate it from the engine, because it is embedded in just about everything, but we have been working on doing that, and so until that happens HE rounds will continue to have a chance to kill tanks like they always have.

 

So, long story short:

 

It could be a bug (and #1-4 above will help determine this), or it could be the typical case where a new update comes out, and New HE draws attention to something that always existed (old HE kills).

 

But without more information provided, we will never know.

Ok there will be more to share after upcoming test are completed. As far as the test results from yesterday. The pictures posted above was one shot one kill to both tanks at 700 meters. The test scenario is the same scenario posted by Colebrook in this thread as reference to my AAR. Only change to that scenario is 2 SEP’s replaced 2 Leopard 2E. As far as other tests conducted I have been able to kill Leopard 2E’s and SEP’s under 5 OF-26 rounds to each vehicle per test. Normally it takes 1 to 2 round for the vehicle to become non-combat effective being badly degraded that it cannot continue to fight. My aiming point has been center mass and a little upper right above the right Turret Armor plates (tank facing you). I will provide many more screenshots and AAR’s showing the results. 

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So then we need an AAR, and the exact test scenario the AAR is associated with. Preferably in the AAR, it needs to happen more than once (because this addresses the "one in a million" possibility).

 

As for a tank being rendered heavily damaged in one or two hits of OF-26, this is fine. We are talking about the tank being directly hit by a 125mm HE-Frag round, essentially direct fire from artillery. Its the kill damage we are looking into, whether or not its happening with "new HE" (which would be a bug and could be fixed in the short term), or with "old HE" which would be known, described above, and is a long term issue.

 

Beyond that, we wait for more information...

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Here you go:

We did some scenario test. It seems to be very random. But there is one incident that should be looked at. I posted a screenshot. It seems my OF round was above the Turret on the SEP but destroyed the SEP.

SS_19_54_49.jpg

thfgh_10212_102419DESKTOP-UHDQ2024.aar thfgh_10212_102419DESKTOP-UHDQ2003.aar thfgh_10212_102419DESKTOP-UHDQ1945.aar thfgh_10212_102419DESKTOP-UHDQ1932.aar thfgh_10212_102419DESKTOP-UHDQ1925.aar thfgh.sce

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Thanks for those files.

 

After looking at each AAR, I can say that these are all "old HE" issues, as I suspected earlier.  I am a bit relieved to be honest, so thanks for helping to verify what the issue is.

 

Not sure if anyone is reading everything I am typing, but you know its "old HE" if the destroyed state is not caused by "overpressure".  This is was fixed in this thread - the overpressure induced kills, and so the issue is still fixed after looking at these AARs. Basically, due to a small error in the formula/calculation, it was possible to kill a tank via overpressure effect with OF-26 in the previous version.  This was corrected, now tank kills by OF-26 are from direct impact effects only, which is from the remaining old behavior from "old HE".

 

Overpressure effects and fragments are what are new with "new HE" in 4.1. When a vehicle is hit, if you go to the sub events, then anything labeled with "(overpressure)" on the end of the damage is damaged caused by over pressure.

 

All the destroyed events from HE in these AARs are caused by non-overpressure events, and so these are "old HE" effects that we are trying to get rid of in the long term, like perhaps by  version 4.2 or higher. Also, these non-overpressure HE kills worked like this in all versions prior to 4.1.  In other words, all of these impacts should also result in a kill in 4.0 as well. If you still have 4.0 installed, then you can see it there, more so actually from the kills factored in from the proximity hits as well (which are now gone in 4.1).

 

BTW, the roof hit on the M1 is a old HE hit on the roof of the tank, which barely clips the roof in the area of the loader's hatch (the LOD1 and LOD3 and AAR do not always match up down to the millimeter). A roof hit of any tank, except perhaps the Leo 2E and Strv 122 (because they have extra roof armor) would certainly cause a kill in "old HE" behavior.  That said, once we completely get rid of the remaining "old HE" behavior, then there will be no more kills like that, from direct impacts, except perhaps for HESH only. But we aren't there yet, and the important think to remember is that 4.1 is no worse than it ever was in past versions, in that regard.

 

So, no bug or math errors here, apart from what we already know about the last remnants of "old HE".

 

Perhaps Ssnake can take some time to explain how the "old HE" worked, and still works to some degree, in regards to impacts on targets, if he has the time, and if he thinks its necessary, I will leave that up to him (I don't think its necessary for me to explain it).  It seems like "new HE" is simply drawing attention to old issues (and who is to say whether or not the 5th 125mm high explosive direct impact on a tank, causing a kill, is unrealistic or not). Clearly no one hasn't complained about it in the past decade or more that this has been the case.

 

 

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4 hours ago, Volcano said:

Perhaps Ssnake can take some time to explain how the "old HE" worked

Actually, I can't. It was a model that was developed without my input, and whenever I asked the programmers to explain to me how it worked, I never received a satisfactory answer. This was one of the key motivations for me to decide that we had to replace it by a new model that would be firmly rooted in documented engineering principles. And here we are, right in the thick of it. Getting rid of that old stuff is just as hard as it is necessary.

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Indeed.  Suffice to say, the HE rounds had a penetration value, which was loosely based off the explosive mass of the round, but it was a heavy abstraction, which is essentially the best that could be managed at the time. This HE penetration value was used to simulate overpressure through splash damage, and direct impacts, which is an abstraction that is no longer needed in "new HE".  However, this old behavior has existed since the late 1990s (Steel Beasts 1), and it will take time to get rid of it entirely.

 

All everyone needs to know is that:

  1. We are aware of the "old HE" remnant behavior.
  2. This observed behavior has always worked like this in previous versions.
  3. We plan to remove it entirely, in the long term, but this is tricky as it involves removing old behavior, and discovering what other connected behavior is broken, and needs to be reworked.

 

(I guess that is about all that can be said about the issue without beating the dead horse.)

 

 

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