[Ultra-Tech] Armor layering and other armor questions

[Anthony]

The real problem is a lot of simplifying assumptions, particularly linear DR vs weight. Truth is, flexible armor that protects against pistols is lighter than rigid armor, and flexible armor that protects against rifles is heavier than rigid armor, because of different protection mechanics. You can also fix this by making rifles armor piercing against flexible armor.

[lexington]

Originally Posted by MatthewVilter

How are you getting those numbers? If you are treating the armor as a normal volume you should use cube root of weight to find thickness which does give ~1.15 for heavy but it looks like you are just cubing weight for the light armor here.

Ah, yes, I have the second number backward.

Increasing the thickness to 1.15 gives it 1.5 times the weight.
Decreasing the thickness to 0.8 gives it it 0.5 times the weight.

In any event using that progression gives much more sensible results in most cases.

[Agemegos]

Originally Posted by lexington

Increasing the thickness to 1.15 gives it 1.5 times the weight.

Not if height and width remain the same. A man doesn't get taller, nor does his chest size increase, when you make his armour thicker.

[DanHoward]

Originally Posted by jacobmuller

IMHO, RAW tells me, you cannot wear a Tactical Suit under anything. Basic Set: Characters, pg286, Combining and Layering Armor "you can only layer armor if the inner layer is both flexible and concealable."
A Tactical Suit may be flexible but I don't think it's concealable.

The "concealable" stat does nothing useful IMO. It just confuses things. Theoretically ANY armour can be concealed, but some are easier than others. Better to get rid of the Concealable stat and introduce a Holdout penalty that is based on bulk and flexibility.

[MatthewVilter]

Originally Posted by Anthony

The real problem is a lot of simplifying assumptions, particularly linear DR vs weight. Truth is, flexible armor that protects against pistols is lighter than rigid armor, and flexible armor that protects against rifles is heavier than rigid armor, because of different protection mechanics. You can also fix this by making rifles armor piercing against flexible armor.

Is that true of ultra-tech-level flexible armor?

Originally Posted by DanHoward

The "concealable" stat does nothing useful IMO. It just confuses things. Theoretically ANY armour can be concealed, but some are easier than others. Better to get rid of the Concealable stat and introduce a Holdout penalty that is based on bulk and flexibility.

I think in Ultra-Tech the concealable nature of the armor reflects the fact that it can be made indistinguishable from normal clothing. But yeah, I don't know that it really works as a "stat".

[Anthony]

Originally Posted by MatthewVilter

Is that true of ultra-tech-level flexible armor?

Probably. It's the nature of how different armor systems dissipate force, and flexible armors are necessarily different or they wouldn't be flexible. In any case, if they aren't different, the hard armors cease to exist.

[MatthewVilter]

Originally Posted by Anthony

Probably. It's the nature of how different armor systems dissipate force, and flexible armors are necessarily different or they wouldn't be flexible. In any case, if they aren't different, the hard armors cease to exist.

So what is the key difference in protection mechanics? Is it projectile velocity? Some kind if diminishing returns on flexible armor? Projectile size? Length?

I ask because this seems like something that could be represented by mechanics that reflect the nature of the technology and physics involved rather than just the fiat of "this is better for this". Maybe not but I hope it doesn't hurt to ask.

[Anthony]

Originally Posted by MatthewVilter

So what is the key difference in protection mechanics? Is it projectile velocity? Some kind if diminishing returns on flexible armor? Projectile size? Length?

It's a combination of velocity (not only do higher velocity projectiles have more energy per unit area, the vest absorbs less energy) and poor scaling (doubling vest thickness doubles energy cost to penetrate; doubling plate thickness is usually more than twice energy cost). Conventional (not even AP) 5.56mm will blow through multiple level IIIa vests (theoretical DR 12) without much trouble.

[gilbertocarlos]

Originally Posted by lexington

It occurs to me that the rules for tailoring weight ought to be revised a bit since DR is proportional to thickness and weight it proportional to volume.

If you make the armor 1.5 times heavier it should provide about 1.15 times the DR.
If you make the armor 0.5 the weight is should provide about 0.125 times the DR.

This actually ends up matching what is in the armor tables. A groin protector and some extra pockets could add up to about a pound.

It does get rid of usefully bullet resistant chemises but I suppose one has to make some sacrifices.

Cube root doesn't make sense if the guy wearing the armor is the same. "cube-rooting" means you're increasing every dimension, if you made that it becomes a giant armor.

You should simply multiply it by (New DR)/(Old DR), so, doubling the weight means double the DR.
Why is that? Simple, you already have the area covered, the only thing you're increasing is thickness, with is only 1 dimension.
Example:
Joe Average has a skin area of 20 sqft. he wears full body armor, meaning his armor also has 20sqft has DR10, it's 1mm thick and weights 10lbs.
He wants to double his armor DR, area remains the same, 20sqft. DR doubles, it's now DR20. thickness doubles, 2mm, Weight is proportional with area times thickness, so, it's 20lbs.

[MatthewVilter]

Originally Posted by Anthony

It's a combination of velocity (not only do higher velocity projectiles have more energy per unit area, the vest absorbs less energy) and poor scaling (doubling vest thickness doubles energy cost to penetrate; doubling plate thickness is usually more than twice energy cost). Conventional (not even AP) 5.56mm will blow through multiple level IIIa vests (theoretical DR 12) without much trouble.

So is it as simple as saying that more layers (from more armor peaces or from heavy tailoring) contribute less to DR? (Like lexington was trying to do but for a different reason.)