Helmets with no padding

[Anthony]

Originally Posted by Bookman

Hrm. This might be stupid, but the mass of the helmet helps protect against acceleration trauma ("rocking the head"), does it not?

Sort of. It still requires the same amount of total force * time to compensate for a blow (and the more massive head may actually absorb more momentum, meaning it's actually harder), but the slower head motion means you have more time to react.

[Ze'Manel Cunha]

Originally Posted by Anthony

Sort of. It still requires the same amount of total energy to compensate for a blow (and the more massive head may actually absorb more momentum, meaning it's actually harder), but slower head motion means you have more time to react (stiffen neck muscles, bend the body to compensate, etc).

Your body can't stiffen to compensate for concussion, that's whiplash you're talking about there.

Unless, of course, you're talking about alien brains encased in stiffening muscle tendrils.

[GodlessRose]

Originally Posted by Bookman

Hrm. This might be stupid, but the mass of the helmet helps protect against acceleration trauma ("rocking the head"), does it not? A 10-pound head wearing a 6-pound helmet will experience significantly less acceleration when struck.

None of the house rules being considered make helmet DR useless, so I don't consider it a big issue.

[Anthony]

Originally Posted by Ze'Manel Cunha

Your body can't stiffen to compensate for concussion, that's whiplash you're talking about there.

The increased mass directly reduces concussion by reducing head acceleration.

[Ze'Manel Cunha]

Originally Posted by Anthony

The increased mass directly reduces concussion by reducing head acceleration.

It's not head acceleration that's a concern, it's brain acceleration which is an issue.

[Anthony]

Originally Posted by Ze'Manel Cunha

It's not head acceleration that's a concern, it's brain acceleration which is an issue.

Brain acceleration is caused by head acceleration. If you don't get the head moving as fast, you don't wind up with as much brain acceleration.

[Wraithe]

Just a couple of minor notes:

This isn't just a LT kind of issue, I'm reminded of a character in John Varley's "The Golden Globe" who, after the protagonist beats him relentlessly, only managing to knock him unconscious after he falls and hits his head on the way down - he turns out to have steel armor surgically implanted under his skull, which DOES protect him from the direct damage (and aftereffects too, as it turns out, but that's different tech), but doesn't help against being knocked out.

I like the rule that Dan suggests, but I would like to apply some sort of bonus/penalty based on how much damage the DR stops/how hard the blow is.

I was initially thinking of having to roll against HT-10 (to match knockdown on skull) with a +1 bonus for the total skull DR provided. So a Minotaur (Total DR 5 on skull) would be rolling against stun at HT-5, and a normal human would be rolling HT-8.

If that seems excessive, then you could go with Dan's straight roll against HT and use the same bonus. So our minotaur would be rolling against stun at HT+5, and average humans at HT +2.

Option 2B would be have the bonus be the remaining DR, so a 5 point blow would have the above minotaur rolling HT, whereas a 2 point hit would have the roll against stun at HT+3.

I think I'm leaning a little more towards option #2 myself, since I know I've taken blows in my 10ga SCA helmet that would probably have dropped a horse, and I shrugged them off (from a "am I really hurt" standpoint, obviously I took the blow as "good". :))

(Side note: Heavy helmets protect from this in two ways, first the armor and padding provide a "cofferdam" effect, with the mass of the helmet slowing things down. Secondly, any really heavy helmet is also going to restrict your head motion, preventing your head from snapping around, bouncing the brain around inside your skull quite so much (in once example, my helmet was driven down until it rested on my shoulder armour, which then took the rest of the blow, dispersing the rest of the impact)

[Ze'Manel Cunha]

Originally Posted by Anthony

Brain acceleration is caused by head acceleration. If you don't get the head moving as fast, you don't wind up with as much brain acceleration.

You're missing the point on the difference between whiplash and concussion.

Maybe my croquet reference was too cutesy, basically even if you immobilize someone's head, whiplash is prevented, but a concussion on a hit to the head still happens as the impact momentum transfers from the blow, to the brain, which goes sloshing into the skull.

[jacobmuller]

Originally Posted by DanHoward

Looking for a simple rule that differentiates between padded helmets and unpadded ones (like a steel skullcap). I'm thinking of making it easier to get stunned. Perhaps something like

If you are hit in the skull and the attack delivers exactly zero damage after DR then you must still roll vs. HT (no penalty) to avoid stunning (see Effects of Stun, p. B420).

Maybe it's enough that it's more likely to hurt? ie 1DR closer to using the Brain Wound Mod.

Mind you, forcing a Knockdown check for any Zero Point Head Injury is cool IMHO. However, would you apply it for 0 injury from an arrow?

[Wraithe]

Originally Posted by Wraithe

I was initially thinking of having to roll against HT-10 (to match knockdown on skull) with a +1 bonus for the total skull DR provided. So a Minotaur (Total DR 5 on skull) would be rolling against stun at HT-5, and a normal human would be rolling HT-8.

my apologies, I just realized that the -10 is only for a major wound to the skull, so ignore that option, anyways. Now I know why that seemed excessive even as I was writing it. :)