CM:BB 20mm penetration stats for comparision.

[Drusus]

First, Thor has a really respectable bottom armor in the game. The bottom is 100, the top is 150. Sides 150. Rear 125. I think it is this way to make the Thor better at resisting artillery shells. Second, if you aren't hitting anything important with the 20mm, you are doing _no_ damage, no matter if all of your ammo penetrates. I don't think that should be changed.

About the A-10. I don't believe the 30mm gun can penetrate the side armor of modern tanks at the range of 500m, atleast not reliably. Definitely it can't penetrate at the angle of 70 degrees.

When thinking about the advancements made in 20mm guns, you should also take into account what has happened to the 120mm gun. Is the relative penetration of the 20mm gun gone up or down? I don't know.

[Los]

"Los,

the fact that the calibres are 20mm, 76mm, 120mm, respectively, kind of invite a comparison to past and contemporary weapons, don't you agree?"

No I wouldn't agree at all. The only thing for sure that a 20mm from WW2 and the far future could have in common at all is that they're 20mm in diameter. One could be a 2' long long tungsten spear humming along at 3500 fps and the other could be a 2oz hunk of lead trundling in at 1200 fps. All depends on what BTS is modelling.

I mean fifty caliber musket ball and a fifty caliber AP round from an M2HB are both about the same width.

Los

[dan/california]

I would have to agree with the relative effectiveness school of thought here. What ever is making the 20mm more effective would also be applied to make the 120mm more effective in the absence of a specific reason otherwise. That explanation is not presented in any of the game materials yet.

If the 120mm AP was capable of blowing through any and all of the armor in use it seems to me that the gun designers would trade penetration for more frag damage or do something else with the round to enhance lethality at the expense of penetration. In the absence of a one shot kill capability the 120mm as currently configured does not seem to be a very viable choice.

I would go very heavy with ATGM vehicles for long range with many 20mm ones for short range under current rules. A very slow vehicle with a low rate of fire must have a one shot kill capability, or why pick it? ever?

Maybe the 120mm needs a shotgun/cannister style round that will just waste light vehicles at close range. That wwould really make the lighter guys think twice about trying to get close. A fair number of 20mm size munitions would fit inside a 120mm round and the initial velocity would be as least as high as the 120mm. It would fall off quick in atmosphere, but so what. Need it for infantry anyway, when they show up.

[Thomm]

Los,

Your reasoning is certainly convincing!

Consider my comparison a 'first guess' attempt at estimating the drop of performance of the 20mm at range.

From then on, thanks to Drusus, we can discuss the actual game data.

Best regards,

Thomm

[Netherby]

Many newer AFVs have more significant underside armour these days, in response to mines etc.. So it's not unreasonable that the Thor has decent underside armour..

I really believe the main issue with the 20mm gun is that even hitting the side of the tank at a 179º angle will still give you penetration.. If the shell was more heavily effected by the angle of the shot you would have fewer kill positions and actually have to try and get behind it.. Currently you can go head to head vs the Thor and still get side hits quite easily because the acute angle doesn't significantly effect the shot!

The Apollo is at a terrible disadvantage since the frontal armour is easily penetrated by the 20mm rounds, I personally think that should be changed.. Why ever use the Apollo if its armour doesn't even protect you from front on 20mm? I also think the 20mm Apollo variant is sort of useless, why would you ever pick it? Its armour wont help you in close combat with other vehicles and it's much slower than them..

Rear penetration with 20mm vs the Thor is fine, but side and side turret penetration seems too much, especially when you can easily spray the fuel cell.. Current M1A1s do not take damage to the side from 20mm, even AP-RPGs are only able to penetrate the armoured skirt of the side, not the hull or turret.. I believe 1 or 2 WERE disabled from 20mm to the rear though.. These were mobility kills only..

Frontal penetration against the Apollo should really be reconsidered..

[pipilongbeard]

I have found only 1 instance on the web (If it can be assumed to be accurate) where a newer soviet anti armor round actually penetrated the hull of an M1A1 and it went right behind the loader seat and loged on the other side. The hole was I think less than 2in. in dia. and suffice to say did not stop the tank. Engine, Tread or Crew damage is the only way to stop or slow a tank. I would suspect the 20mm would be able to hit the engine but a frontal attack, no way, and then maybe a 25% change to penetrate on a side shot.

As pointed out in previous posts, if a fast moving, high re-fire rate vehicle can take on a tank why would anyone ever take a tank?

[Moronic Max]

I have found only 1 instance on the web (If it can be assumed to be accurate) where a newer soviet anti armor round actually penetrated the hull of an M1A1 and it went right behind the loader seat and loged on the other side.

And how many instances did you find of a newer soviet anti-armor round actually being used on the hull of an M1A1?

[Mace]

Originally posted by pipilongbeard:

I have found only 1 instance on the web (If it can be assumed to be accurate) where a newer soviet anti armor round actually penetrated the hull of an M1A1 and it went right behind the loader seat and loged on the other side.

I think this was the M1A1 that was penetrated from the hull side during the initial stages of the advance into Baghdad?

IIRC they suspect it was penetrated by an RPG-27 or RPG-29 which features tandem HEAT warheads, rather than conventional AP.

[ClaytoniousRex]

I can't wait to dive into this discussion (and a few others like it around here), but we're focused purely on bug fixes right now. With 0.9.42 going out soon the bulk of the nasty bugs will be out of the way and we'll once again be able to get back into the really fun stuff like this.

Just wanted to post this to explain the silence from us developers on these things for the moment...

[ClaytoniousRex]

I will be running a server called "Drusus Test" from time to time, there _will_ be different values used. Be warned.

Drusus, the "polite" way to do this is to run a Mod on your server so that the public can plainly see that something's different. Here's a brief summary of how to do that.

Create a new directory under the "Mods" directory. Name this directory with the name of your mod (e.g. "Lethal"). Create another subdirectory beneath your mod directory called "data". Put a file called Description.txt in there with a description of your mod. When you run your server with this mod using the mod command line argument, any data files in this new data directory will override those in the base data directory. For example, if you want to make a more lethal 120mm AP round, then you could copy 120mmAP.physicalobjectgroup from the base \data directory into your mod's \data directory then modify values within the file. Now when your server runs under the "Lethal" mod, this new 120mm AP round will be used instead of the base one. If you have questions on this then feel free to email. It's probably terribly boring for everyone else!

[Drusus]

I got my server working with a custom mod, thanks for the help! Is there a way to have a default welcome message for the users of the server? Would be usefull, not only for testing servers, but I think there would be other uses as well. Editing the "your objective is to capture the enemy flag..." text which pops up at the beginning of each round doesn't work, as the scenario files are CRC checked or something.

One question about the game. Will there be changes to the unit values or the underlying penetration / damage system in the upcoming 0.942 version? Looking at the minor verison number change, I would think only bug fixes, but it never hurts to ask. If the underlying system is changed, then there is not much point to do any "serious" modding right now. I have something tested, but usually the system falls apart because I am trying to change too many things at one time. I need version control system, atleast one working inside my head.

Send you an email about something else, would not be interesting to larger public...

[Drusus]

Ok, more things cleared. The reason why 76mm and 20mm to lesser extent feel so ineffective against the Thor is now clear. The engine is behind the fuel cells. While the engine is operational, it seems it will stop always the projectile. This means that if you want to destroy the tank from behind with hull shots you need _at least_ 6 perfect 76mm shots. Propably much more, as the engine has 80hp. It might be 10+ shots for guaranteed kill. And all this time the Thor is very much capable of fighting back. It will lose it's engine after 4-6 shots, and after 3-5 additional shots the Tank will explode. If you have a chance to fire to the turret back it is a much better choice. 3-4 shots and the turret will be in flames meaning the tank is no more usable as a weapon.

If thinking what a reasonable tank desginer would do, he would switch the place of the engine and the fuel cells. This way the fuel cells would be better protected from the front. It is also worth considering why the engine stops compeletely the AP projectiles while operational but doesn't do anything once not operational. Suggestion: "armor value" to the engine. If the projectile has more than this value energy after penetrating the main armor, the projectile will continue its way through the engine.

This same effect means that the Paladin is actually harder to kill from front. There is the engine, and the driver might get inbetween. The effect doesn't hit 20mmAP as much, because of its great effect from close range. While 120mmAP might suffer from this, if you get to fire to the rear of a tank you will proably use HEAT. I am quite sure that this is the effect that causes so much complaints about weapons effects.

Anyways, currently the Thor seems to be tougher from rear than flanks which doesn't feel right.

I have had the feeling often. Yes! I got that Thor surprised. Now it is just a few shots through that weak rear armor and it will be in flames. Then begins the shooting. You see the turret turning not so slowly towards you. The shooting continues. Maybe you win, maybe the Thor wins. If you are using 76mm, the Thor _will_ win. If you lose, the feeling after this is that you have been robbed a sure kill. You were behind him. He noticed you when you started shooting. And still he wins. Feels just so wrong! Even more so when you know you could have taken the Thor out with 3 20mm bursts for sure (close range, surprised target).

I was wrong about the hit points not taken into account. The problem is that the driver has 50 HPs while the fuel cells have the same amount. Engine has 80. As I see it, the driver should be protected with a compartment (armor) but if that inner compartment is breached, then the driver should be pretty easy to kill. I think I can add armor to inside objects, but I am not sure if it will work as intended.

[Bnej]

Well, I just killed 6 Thors one after the other on the Raid map, then two and an Apollo the next try, it's really not hard. I wasn't doing it before because I didn't think it was possible, but now I know how to do it it's really easy.

Even if it's a slugging match, you usually win, because unless they turn their hull to you immediately, they're toast by the time they take their second shot.

There needs to be distinct levels of capability I think. Right now, on the Raid map, the 20mm Paladin rules all - the terrain allows it to rush or ambush all the way. The ice map has the ice patches to stop rushing, which gives the 120mm gun a range advantage, but otherwise the 20mm vehicle has the speed to dictate the fight and the close in lethality to win when it gets the first shot.

I actually find with the game as it is that penetration is not a problem, it's accuracy & lethality that's making units more or less effective. All of the weapons penetrate all the vehicles, in the right conditions, so it comes down to the number of shots you need to win.

[ClaytoniousRex]

I really believe the main issue with the 20mm gun is that even hitting the side of the tank at a 179º angle will still give you penetration..

Yes, this was in fact a bug that is now fixed in 0.9.42. We would love feedback on how things feel now with this bug fixed.

As for comparisons between 20mm AP in DropTeam and those in WWII, remember that the rounds in DropTeam are uranium cores wrapped in a nano-lattice of carbon (like a net of bucky balls) to provide *incredibly* high tensile strength.

[dan/california]

My only question then is why the 120mm AP won't shoot through a thor lengthwise and go several hundred meters into the mountain behind it. It is a question of relative, not absolute effectiveness.

[ClaytoniousRex]

why the 120mm AP won't shoot through a thor lengthwise

It will. The previous comment by Drusus that AP does not overpenetrate through multiple components inside of the target was not true (as he later posted). A 120mm AP that penetrates will go through everything inside the target. This is a big difference between it and the 20mm, which will almost always be stopped by the first internal component that it damages.

[Neutrino 123]

I don't know the dynamics of armor penetration very well, but I would think that high tensile strength would tend affect armor penetration at all times. The rate of penetration decline vs. distance, however, would be more affected by the cross-section, air density, and total mass of the shell. Since the 20mm shells in dropteam are almost certainly more dense (from the uranium) then WWII 20mm shells and possible longer as well, they would retain their energy better as they fly about (so assuming they had the same muzzle velocity and normalized initial penetration, the WWII shell would lose penetrating ability more quickly). This can be calculated with a simple differential equation.