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algcs
Given A

QUOTE
The reason APDS ammo punches through barriers better than regular ammo is because regular ammo is made of lead or similar materials that deform and expand on impact with a barrier, while APDS ammo is built to have a smaller area of impact. It's the same reason an ice pick punches through barriers better than a hammer: it's the same amount of kinetic energy being transferred, but the ice pick focuses it all on a much smaller area, making it easier to punch a hole in something. Regular ammo actually does more damage to a target because it transfers more of its kinetic energy to the target, but when it strikes a barrier more of the kinetic energy is also transferred to the barrier for that same reason. APDS slips right through the barrier because it doesn't deform, leaves a smaller footprint on the barrier, and passes through, retaining more of its energy.


And B

QUOTE
When used, APDS halves (round down) the Ballistic Rating of armor or the Barrier Rating of an object in any attack.  APDS is not anti-vehicular and is therfore treated as normal ammunition against vehicles and drones.


So what is so special about a vehicle that the bullet resistent glass I put on it defeats AP ammo while the bullet reistent glass at the service station stays vunerable?

toturi
You are presumably shooting at a vulnerable area of the vehicle. If you target the glass specifically, there is nothing to stop you from shooting up the glass on a car.
algcs
QUOTE (toturi)
You are presumably shooting at a vulnerable area of the vehicle. If you target the glass specifically, there is nothing to stop you from shooting up the glass on a car.

I was using glass because the door was used in the Armor spell thread. If it makes you feel better I'll switch the example to use that.
Austere Emancipator
Nothing. In my games, there is no inherent difference between personal armor and vehicle armor. There just tends to be a whole lot more of the latter, and AP(DS) still gets its Power halved and DL reduced by 1.
Cray74
QUOTE (algcs)
So what is so special about a vehicle that the bullet resistent glass I put on it defeats AP ammo while the bullet reistent glass at the service station stays vunerable?


Sure, the materials are the same, but are the transparent armors equally thick even if the Barrier Rating in the service station is the same as the Armor Rating of the car's windows? You said it yourself: the car windows defeat APDS's armor piercing ability. The station's windows do not.

Clearly (pun intended), they are not quite the same, even if they are made of the same stuff.

Perhaps if an armored car window were mounted at a service station's counter, it would have a higher barrier rating than its vehicle armor rating. That would be one way to represent defeating the AP feature of APDS.

Interesting real world factoid about service stations: One of my college roommates worked with a construction crew that installed the heavy polycarbonate armored windows in service stations. He found it amusing that, sure, the windows were armored, but the counters below the windows were just drywall. Note to psychotic robbers: aim low.
algcs
QUOTE (Cray74)
Perhaps if an armored car window were mounted at a service station's counter, it would have a higher barrier rating than its vehicle armor rating. That would be one way to represent defeating the AP feature of APDS.

I was thinking more along the reverse. Players scavaging things like bullet proof glass and armored doors to build Mad Max like cars.
Tarantula
I'd say, if you wanted to put vehicle armor up as a barrier, double its value and that gives you the barrier rating.
Cray74
QUOTE (algcs)
QUOTE (Cray74 @ Dec 8 2004, 10:14 AM)
Perhaps if an armored car window were mounted at a service station's counter, it would have a higher barrier rating than its vehicle armor rating. That would be one way to represent defeating the AP feature of APDS.

I was thinking more along the reverse. Players scavaging things like bullet proof glass and armored doors to build Mad Max like cars.

Alright. Then maybe halve the Barrier Rating to determine Vehicle Armor rating.
Kagetenshi
It'd be arguable that past Armor 3 or so you wouldn't actually have windows, just solid armor and a viewscreen.

~J
Tarantula
QUOTE (Kagetenshi)
It'd be arguable that past Armor 3 or so you wouldn't actually have windows, just solid armor and a viewscreen.

~J

Unless its concealed, then its just transparent steel... spin.gif
Arethusa
QUOTE (Kagetenshi)
It'd be arguable that past Armor 3 or so you wouldn't actually have windows, just solid armor and a viewscreen.

~J

Considering we already have bullet resistant glass that can outdo an armor rating of 3, I'd say that's a pretty unreasonable argument.
Kagetenshi
Then kick the threshold armor up a few points.

For concealed, you could always pull the limo trick (steel shutters). Or just have fake windows.

~J
Cray74
QUOTE (Kagetenshi)
It'd be arguable that past Armor 3 or so you wouldn't actually have windows, just solid armor and a viewscreen.

Yep, I'd argue that. I have faith in developments in bulk diamond production, and I know you can get large sheets of artificial sapphire. Layer that stuff with future transparent polymers and you could have very high vehicle armor ratings for windows.

There's concealed vehicular window armor now that'll stop rifle bullets, which suggests an armor rating of 4-6.
Kagetenshi
Fair enough. I was unaware of the progress that had been made in that field smile.gif

~J
Nikoli
I remember watching a show on vehicle armor (the body, not the glass) that could stand up to 2 pipe bombs placed directly against the door. It stood up very well, no interior damage. This was to simulate multiple strikes from an RPG.

One of the things that the SR abstract armor system does not do well is the diminishing returns that armor, body or vehicular, provides (with the noted exceptions of the optional armor degredation rules and the ablative armor option). Armor is meant to give you enough time to get out of the way, not stand up to assault after assalt. Not even tanks can stand up to heavy fire forever (though they do seem to be well nigh invulnerable to small arms fire unles you get really [un]lucky)
Austere Emancipator
QUOTE (Nikoli)
I remember watching a show on vehicle armor (the body, not the glass) that could stand up to 2 pipe bombs placed directly against the door. It stood up very well, no interior damage. This was to simulate multiple strikes from an RPG.

Ick. High Explosive RPG warheads, maybe. The HEAT warheads RPGs are supposed to fire will cut through anything less than an MBT or an AFV with reactive armor. Depending on the RPG, some do in fact penetrate MBT armor, other than from the front.

Anyway, as was mentioned, armored glass exists today which can stop multiple strikes from rather high-powered rifles firing solids. This does indeed relate to an Armor Rating as high as 6 on the SR scale -- although obviously HMGs should go right through and Heavy Pistols wouldn't bother most armored glass at all, and the other usual SR problems.
Nikoli
Well, the stuf on limos is typically not meant for assaults against heavily fortified emplacements, but rather to survive an attack from underfunded, poorly trained (in comparison) personnel who are as interested in scaring the populace as killing the target.
Austere Emancipator
I understand that, it's just that being protected against RPGs basically means being protected against rather heavy anti-armor weaponry. Bradleys, for example, are not particularly well protected against RPGs, and the antique HEAT RPG-7 warheads employed by insurgents in Iraq can bust them.

As a demonstration of good protection it may have worked. It didn't demonstrate protection against RPGs, and there is indeed little point making a civilian vehicle that is protected against such threats.
Arethusa
In general, they don't try and claim protection against RPGs (even the old RPG-7s and their HEAT rounds), and I imagine the pipebombs were intended to demonstrate protection from hand grenade type threats more than anythin else.
Nikoli
One piece of footage they showed was a limo that was hit 3 times with RPG's, twice to the front and once more was near enoughto rock the vehicle. The footage was real, taken by either journalists or the attackers for use later, I'm not sure which. The limo was able to continue and it managed to escape, but onyl because the attackers ran out of RPG rounds.
Cray74
QUOTE (Austere Emancipator)
I understand that, it's just that being protected against RPGs basically means being protected against rather heavy anti-armor weaponry. Bradleys, for example, are not particularly well protected against RPGs, and the antique HEAT RPG-7 warheads employed by insurgents in Iraq can bust them.

As a demonstration of good protection it may have worked. It didn't demonstrate protection against RPGs, and there is indeed little point making a civilian vehicle that is protected against such threats.

There's more than one damaging effect from an RPG.

Sure, you cannot reasonably stop the shaped charge jet of an RPG, but that jet (probably) wouldn't kill everyone in the passenger compartment by itself. It is rather focused, though it can scatter a bit (particularly after penetrating armor - irony).

However, there are other effects that armor can deal with.

The explosives that form the jet do not only blow inward; they detonate in all directions like any explosive. Dual purpose shaped charges wrap shrapnel around the warhead to take advantage of that effect, while even normal shaped charges can generate shrapnel from their area-effect blast. An unarmored window can be turned into glass buckshot by a nearby RPG detonation. An armored body panel and armored windows will minimize the danger of an RPG's area effect explosion.

The process of the jet going through the vehicle can generate shrapnel from the vehicle's body and armor, too. The shaped charge jet doesn't make material disappear - it shoves out of the way, mostly ahead of it. This burst of spalled material can be lethal and fill much more of a passenger compartment than the jet itself. But the spallation process can be minimized with proper armor layout. A backing layer of high-toughness steel or Kevlar might catch all the material except in the direct path of the jet.

Separating vehicle compartments (engine, passenger, trunk) with armor can prevent an RPG detonating in one compartment from spreading its message of love and pieces.

Interior armor - like seat cushions laced with kevlar - can soak shrapnel before it rebounds and gets a second chance to find meat.

Of course, the poor schmuck sitting in the path of the RPG's jet is still going to do the Chunky Salsa Dance, but that's no reason to abandon all hope of protecting a vehicle from some RPG effects.
Austere Emancipator
Good points there. I guess I'm just more used to considering "protection against" something to mean there's little if any penetration, which is how it is in the military for the most part.
algcs
QUOTE (Cray74)
Sure, you cannot reasonably stop the shaped charge jet of an RPG,

Actually I've read an article on defeating the shaped charged jet by using layered armor. Note: It has been a while since I've seen the article. It was over in the battlefront.com general forum. I'll see if I can dig it up when I get some time.

The idea was that you had two layers of armor with a high voltage potential between them and some insulator in the middle. When the jet penetrated the insulator the resulting flow of electricity would be enough to disrupt the jet.
Cray74
Yes, "electromagnetic" or "electric armor." I did a conversion of that for Battletech.

I refrained from mentioned electric armor because I think electric armor, like reactive armor, still needs a substantial backing plate to stop the disrupted packets of the shaped charge jet. Sure, the electric charge blows the jet apart like a fuse (neat trick, IMO), but it doesn't cancel the forward movement (3000-8000m/s) of the jet's material. I would be surprised if less than a centimeter of steel would stop the disrupted jet.

Pleasantly surprised, but still surprised.
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