Ammo stowage hits

[ChrisWerb]

I'm not trying to stir things up, but, from a realism perspective, having received quite a few hits that took out my main gun ammunition stowage, in its entirety, in a variety of vehicles (Particularly M1xx. Leo2xx, Leo1xxm Marder and Piranha 3C DF30), I'm wondering what kind of real-world hit would take out the entirety of the ammunition stowage in any of those vehicles without killing the vehicle and its crew (possible exception DF30) outright. 

Edited September 15, 2019 by ChrisWerb

[Grenny]

1. Ammo storage with blast doors.

2. model fidelity, so the seperated storage areas for ammo may not be modelled in enough detail. (which is OK for most tanks IMO, when the turret bunker cooks of, most tanks are not in shape to fire their gun anyway)

Edited September 15, 2019 by Grenny

[ChrisWerb]

Sorry Grenny - re blast doors, that's why I said "entirety of" - of course there would be cases where the hull stowed rounds would already have been expended.  I hadn't considered model fidelity. My bad.

[DarkAngel]

1 hour ago, Grenny said:

1. Ammo storage with blast doors.

2. model fidelity, so the seperated storage areas for ammo may not be modelled in enough detail. (which is OK for most tanks IMO, when the turret bunker cooks of, most tanks are not in shape to fire their gun anyway)

DF90 ammo isn't in any sort of safe ammo storage. Look behind you, those are the rounds all over the back wall.

[Maj.Hans]

2 hours ago, Grenny said:

1. Ammo storage with blast doors.

2. model fidelity, so the seperated storage areas for ammo may not be modelled in enough detail. (which is OK for most tanks IMO, when the turret bunker cooks of, most tanks are not in shape to fire their gun anyway)

Pretty much this.

 

I think that, at this point, the SB team has decided that it isn't worth modeling the separate storage.  They might be right.  Off the top of my head, the only tanks with blow out panels for some or all of their ammo are the Leopard 2 and the M1 Abrams series.  The way it is now, it's possible to take a hit that blows the panels off, which makes all main gun ammo disappear.

 

In the real world it is possible that a Leopard 2 or an M1 that took a hit to the turret ammo (or, in the case of the M1, a hit to the hull storage) only could continue to fight, but I can't imagine that it would be very effective.

 

In a 105mm armed Abrams you would be reduced to one round in the gun, and three rounds in the "rapid rack" near the gun if it were in usable condition, plus the remainder of whatever storage compartment hadn't been blown up, so it's maybe possible that an M1/IPM1 could keep fighting by topping off the rapid rack from the hull.

 

In the 120mm armed Abrams, a hull ammo loss might not mean much if the tank was otherwise OK.  But a turret ammo storage loss means you're either going to reload one round at a time, very very slowly, from the hull ammo storage into the gun, OR you're going to scatter ammo around the turret, and still wind up with only 7 rounds at most.

 

For the Leopard 2 it doesn't really matter where you put the hull ammo storage, but I can't imagine that it's safe to load from the hull ammo storage while the tank or turret is in motion.

 

All things considered it would be nice to model that level of detail, but do we really need it?

[Ssnake]

There's a (=one) generic damage for "ammo storage" which then applies to all ammo, whether it's stowed in separate compartments or not. Maybe one day we'll go into more detail, but the decision for this approach was made with the transition to the polygon based 3D engine some 15 years ago. I don't remember anyone bringing up this topic (without doubt others noticed it), so I guess it was the right decision for the time.

The more we're going into detail with our simulation, the more obvious are the results of certain abstractions.

Also, I suppose that the longer you play Steel Beasts and the more you learn about it, and tanks in general, the easier it is for you to spot simplifications and abstractions. From that perspective, it's a win for us.

[Maj.Hans]

I kinda think this is one of those things that would be "nice to have", but I wonder how much work needs to go into implementing it?

 

Not only is it the new code to the damage model, but now if you want to make this useful, you've got to implement new reloading code...

 

M1 and IPM1 need to be able to load from the hull stowage, and into the 3 round "rapid rack" near the gun.  I suppose with four rounds 'on tap' you could keep fighting.

 

But for the M1A1/A2 and Leopard 2 now you need to simulate loading the gun one round at a time from the hull, or lap loading now, or leaving ammo stacked up around the turret basket, which means more damage model changes...

 

There's other things I'd probably rather have instead.

[dejawolf]

the leclerc as well. possibly the challenger 2 as well with it's wet-stored ammo.  

and the Armata has all it's stored ammunition outside in the turret rear. 

 

for the IFVs, possibly the pizarro, DF30, kurganets. although more likely there's going to be a nasty ammunition fire. 

[Volcano]

One thing we already do have is that certain ammo storage areas are designated as 'stored ammo' (ie. not ready ammo). Once stored ammo is all used up, then those areas are ignored (they will not trigger explosions anymore). So in that respect, we do model a real difference between stored and ready ammo in regards to vulnerability.

 

Also, if you want to have a less vulnerable T-72B1, or less vulnerable Leopard 2, you can choose to remove all the stored maingun ammo, which is something that is considered in real life situations. (Or at least that is how the feature is supposed to work anyway.)

 

Just saying.

[Lumituisku]

10 hours ago, Volcano said:

One thing we already do have is that certain ammo storage areas are designated as 'stored ammo' (ie. not ready ammo). Once stored ammo is all used up, then those areas are ignored (they will not trigger explosions anymore). So in that respect, we do model a real difference between stored and ready ammo in regards to vulnerability.

 

Also, if you want to have a less vulnerable T-72B1, or less vulnerable Leopard 2, you can choose to remove all the stored maingun ammo, which is something that is considered in real life situations. (Or at least that is how the feature is supposed to work anyway.)

 

Just saying.

Out of curiosity. Do you guys remember how it works if you leave hull ammo purposefully empty.  next time you go to supply unit...  from where the filling begins?  Ready rack I guess?    And it will automatically proceed to fill all ammunition or the last setting?  

Edited October 30, 2019 by Lumituisku

[TankHunter]

I'm pretty sure it tries to fill all ammunition.

[Ssnake]

But it fills ready ammo first.

[Lumituisku]

THANKS! 

[ChrisWerb]

On 10/30/2019 at 5:39 AM, Volcano said:

One thing we already do have is that certain ammo storage areas are designated as 'stored ammo' (ie. not ready ammo). Once stored ammo is all used up, then those areas are ignored (they will not trigger explosions anymore). So in that respect, we do model a real difference between stored and ready ammo in regards to vulnerability.

 

Also, if you want to have a less vulnerable T-72B1, or less vulnerable Leopard 2, you can choose to remove all the stored maingun ammo, which is something that is considered in real life situations. (Or at least that is how the feature is supposed to work anyway.)

 

Just saying.

I've definitely had vehicles (T-90s and Armatas) from which I have removed all ammo explode on many occasions during testing (almost always, given the correct shot placement). I'm not asking for any changes to how damage is modelled, just giving my findings. Those AARs I posted on the earlier thread had all vehicles devoid of ammunition (to stop them shooting back, without disabling the gun  ) and plenty of those blew up.

[Maj.Hans]

On 10/30/2019 at 12:39 AM, Volcano said:

Also, if you want to have a less vulnerable T-72B1, or less vulnerable Leopard 2, you can choose to remove all the stored maingun ammo, which is something that is considered in real life situations. (Or at least that is how the feature is supposed to work anyway.)

OK that's good to know.

 

I assume that in the case of the T-72 there is still going to be a chance to KaBoom! the turret if you strike the Autoloader?

[ChrisWerb]

OK, I did some more testing. 

 

Five three tank platoons of Russian tanks from the T-62 to the Armata. All ammo removed (even MG and smoke discharger grenades). Shooter is a Leo2A6 with DM53. Shot placement to the lower hull aligned with the centre of the turret to hit the carousel (except for the T62 when I aimed into the front hull from the side due to its different ammo storage arrangements). I did this test three times and got interesting results each time. I'm posting the AAR from the last one. All tanks either blew up, roman candled or burned (of which in earlier tests some subsequently exploded), (though sometimes this took more than one shot) except one Armata which would not ignite regardless of where in the carousel area I hit it. This time I'm including the scenario so you can repeat the test if you wish to.

 

Disclaimer: This post is not intended as a criticism of or harrassment of the SB team or any member thereof, or in any way a statement of disastisfaction with SB. 

 

Exploding_ammoless_vehicles_4832_110219HP-Z4401308.aar Exploding ammoless vehicles.sce_4_11-02-19_13_08_17.htm Exploding ammoless vehicles.sce

Edited November 2, 2019 by ChrisWerb

[Ssnake]

Thanks a lot for investigating this. Looks like some refinement needs to be done.

[Volcano]

No. The ready ammo “boxes” in the armor model will ALWAYS trigger an explosion regardless (even if the vehicle has no ammo assigned to it), it’s just the limitation of how it all works, but then again AFVs are rarely completely out of all ammo, unless you do it intentionally.

 

As I said, it’s for stored ammo, because stored moves to ready, and we don’t want explosions when all the stored ammo is used up, which happens very often, and we also want it to be viable to do what is sometimes done in combat - like on T-72B1 - where all stored ammo is removed for more survivability. Of course the oldest vehicle models don’t support this though, either - there is always that caveat.

 

But I guess that’s the trouble with mentioning a feature - we get to then pick it apart and point out limitations. I guess sometimes it’s better to not say anything (or at least we have to be extremely careful about the wording). 😉

 

Really I just threw it out there as a side comment of how stored ammo is modeled on most of

the newer vehicle models. And yes, of course there is a lot to improve but the limitations are known and it works as designed (AFAICT).

[Hedgehog]

Challenger 2 has armoured bins, I don't think they are "Wet Stowage" like the Chieftain and Challenger 1 and all explosives are below the turret ring.

 

I'd expect Roman Candles from an older "Empty" tank, as Hydraulic fluid is pretty flammable once its atomised.

[ChrisWerb]

Sorry Volcano, the fault is mine as usual. There was nothing wrong with your original explanation either - I just didn't click that carousel stowage was "ready" rather than "stored". I completely understand that with c. 250 vehicles in SB, they are not all going to be kept updated to the same standard of damage modelling. I am still learning about the way damage is modelled in the game and about the vehicles themselves, both as modelled here and as they exist in RL. Your explanations made me work to understand how to kill the Armata and I discovered it had significant vulnerabilities and was eminently defeatable, particularly with solid combined arms tactics as others have pointed out.  I did not know, for example that Roman candles were the result of hydraulic fluid. I thought they were the result of a penetration into a cased round setting off propellant (which is silly as they sometimes happen with vehicles using caseless or stub only case ammo), so Hedgehog's explanation makes a lot of sense. I read somewhere a long time ago that hydraulic vs electric turret drive made a significant difference to crew survival in Israeli M48/60 vs Centurion which is why they and I would be amazed if Armata used hydraulic. I think later M60s went to electric traverse, retaining hydraulic elevation and the M1 was electric from the start. The fact that vehicles with no ammunition in them blow up is of no consequence in target vehicles from a training perspective as you want to train users to aim to penetrate the carousel anyway - trainees will never know for sure that an enemy vehicle is out of main gun ammo after all. It really doesn't bother me from a vehicles on my side in gaming perspective either, particularly as the effort by yourselves to make ammo explosion probability truly realistic would be non-trivial to say the least. 

Edited November 3, 2019 by ChrisWerb

[Ssnake]

1 hour ago, ChrisWerb said:

I did not know, for example that Roman candles were the result of hydraulic fluid.

...nor would I use that as an explanation. Yes, ruptured hydraulic lines tend to spay oil in a fine mist, and aerosolized oil can lead to deflagrations, but they are a one-time kaboom, probably followed by a longer fire. The torch-like flames out of hatches are, in real life, indeed propellant containers burning off without the confinement of breech and barrel.

I am against rationalizing everything that can be seen in Steel Beasts as rooted in deep science. A lot of it is, but when it comes to visual effects we take the pragmatic approach and look at what gives a reasonable effect most of the time. We have certain damages that result in fire, and possibly, also in "a" catastrophic kill effect, the roman candle being one of them. Maybe there is a way how, in code, we can reduce the chance of this effect (and flying turrets) being used if the amount of ammo left in a vehicle is low. This might be a reasonably simple way to bring rising expectations in line with what's actually doable with the finite manpower resources at our disposal. We will certainly not go through every single vehicle model and try to fine-tune the assignment of damage likelihoods to all the different elements, that's simply out of scope.

[ChrisWerb]

Hi Ssnake - I thought that with combustible cases or bagged charges etc. (if not in water jackets etc.) touching off one would set off the others so fast that there would be an explosion, rather than a Roman candle, it's just that the explosion would be a "low order" explosion, perhaps blowing the turret off, rather than a "high order" explosion, through sympathetic detonation rather than ignition. which, particularly when the vehicle is carrying a high proportion of HE and HEAT rounds, will tend to totally blow the vehicle apart, as seen in some knocked out MBTs in Ukraine. This may be an incorrect interpretation on my part.

 

I marvel at the work that has gone into SB every day and, as you know, I am a huge and consistent proponent of SB elsewhere.

Edited November 3, 2019 by ChrisWerb

[ChrisWerb]

PS: This is what I would expect from propellant in cased ammo being ignited.

 

Edited November 3, 2019 by ChrisWerb

[Ssnake]

Well, my interest ends at about the point where the first propellant case goes off inside the crew compartment. Whether a fast or slow chain reaction follows, who knows. Maybe it is as you say. Maybe it depends on additional factors, e.g. if multiple cases are ignited (near) simultaneously. In the Leopard 2's hull bunker each round is surrounded by an aluminum tube which arguably fulfills the same role as an individual round's brass shell casing. The exposed parts are the projectile heads themselves and the aft caps. From the photos of Turkish Leopards in Syria we can see that this is no absolute protection; if there's a direct hit that might ignite multiple rounds simultaneously, clearly the gas pressure build-up is so rapid that the turret gets lifted from the hull; in fact, some hulls ripped apart at the welding seams, so it's obvious that it can be a very violent event.

From the cases where M1 ammo bunkers were hit and we saw the cover plates flying, my take is that even if you have 17 rounds in close proximity an explosion is not guaranteed, but a 30...40 second long intense fire can just as well happen. So, examples of similar events that show different behavior. The conclusion for us is: It's a random selection of what kind of effect we show. Maybe we can reduce the chances of spectacular effects if there is little ammo left in a future version; if it's something that need to be done on a per-vehicle basis (something that we still need to find out) this may take a good while before it happens. It's certainly not a top priority thing, to be honest.

Our top priority is the development of a new software architecture to make Steel Beasts more efficient, so we can achieve high framerates even witrh mediocre PC hardware. Yes, I can get now consistently 55+ fps in our 4.0-turned-4.1 benchmark scenario with a new notebook, but that requires an absurd investment in top of the line hardware (RTX 2070, i-7 9700K, 32 GByte RAM). We squeezed out of the old engine what's possible with version 4.1, and while it's good progress over 4.0 I still can't say that I'm entirely satisfied. I want everybody to be able to experience solid 60 fps even in big scenarios. That appears doable I'm told, but it will absorb a fair bit of attention from our team to pull it off.

[ChrisWerb]

And that's where I'd much rather your effort went, even if it meant an end to new vehicles or changes to the damage model for the forseeable future. What we've got is entirely workable - it just throws up an occasional anomaly which we can easily chalk up to "unlikely stuff happens in war". When I request something on the Wish List thread these days, it's either something I think won't take a staggering amount of effort (for example, a guided round for the Armata) or it's something that might take significant resources, but will have a huge benefit to realism right across the game (subtley more realistic infantry behaviour). I often just post stuff out of curiosity about how things work, particularly when I see apparent anomalies and things I don't properly understand, and, because of my poor communication skills, it's sometimes taken to be a request for a huge amount of time and effort to be spent on something with negligible training benefit and thus unlikely to generate a financial return, which I really don't want.

Edited November 3, 2019 by ChrisWerb