Steve Jackson Games - Site Navigation
Home General Info Follow Us Search Illuminator Store Forums What's New Other Games Ogre GURPS Munchkin Our Games: Home

Go Back   Steve Jackson Games Forums > Roleplaying > GURPS

Reply
 
Thread Tools Display Modes
Old 11-02-2013, 01:11 PM   #1
Kallatari
 
Join Date: Jan 2006
Location: Ottawa, Canada
Default Pyramid 3/52 - Low-Tech Armor Design - Comments and Questions

First, just wanted to take the opportunity to mention that I love David Pulver's articles on how to build your own equipment.

This post is about the "Low-Tech Armor Design" rules in Pyramid Low-Tech II. I've played around with it a bit, and tried to expand it to all TLs (work likely wasted by GURPS Vehicle Design, but still gives me something to use until that does pop up in e23, which I'm guessing is still a long way off), and recreate an armor catalog for my campaigns. With this post, I'm sharing what I've learned and comments, and also posing questions to the forumites to see what solutions you may have.

So, here we go:

1. Scales and Mail are Flexible

This is hinted at under the definition of the Scale construction type, but not a single mention under Mail. Yet in the RAW, these armors are all Flexible. In this case, I emailed Mr. Pulver and got him to confirm. If you build an armor with the Scales or Mail construction type, then it gains the "F" trait, meaning that it will be flexible if the DR is no greater than 25% of the material's DR/inch trait.


2. Comparison to Armors in GURPS Low-Tech

I've tried to use the numbers presented in the article to more or less recreate the armors in Low-Tech. I general, I've found they came pretty close (within 10% of cost and/or mass).

One interesting observation was that, in GURPS Low-Tech, the relation between the DR and Cost/Mass of armor of the same material and construction type (i.e., comparing light vs medium vs heavy of the same armor) in Low-Tech was not linear... but that wasn't much of a deal, and probably a realistic effect you won't get with the Armor Design article. But the differences were minor enough and still fell within the 10% margin of error.

That said, there were two major discrepancies.
a) The Mass of Scale Armor was significantly lower in the Armor Design rules compared to Low-Tech. By significant, it was so much so that a scale armor of a given DR was actually slightly lighter than a Segmented Plate armor of the same material and DR. In the Armor Design rules it was therefore cheaper and less weight to have Scales armor, making Segmented Plate pointless... since I make the assumption that Segmented Scale was not a pointless armor but indeed an improvement over Scales, I decided to fix this problem. I was able to correct this by increasing the CW rating of Scales from 1.1 to 1.6. This made Scales weight more than Segmented Plate, and brought it to within 10% of the cost and mass of the armors in GURPS Low-Tech. I'm curious if this makes sense to people, as I presume Low-Tech was well researched, and that indeed Scales should be heavier than Segmented Plates for the same DR/material combination. Anyone have comments?
b) The cost of Mail armor was significantly cheaper in the Armor Design rules compared to Low-Tech. Here, I have no clue what the correct values were. I do note that by increase the CC of Mail construction type from 1.2 to 2.5 we wind up with numbers that fall within 10% of the costs in GURPS Low-Tech. Is this a reasonable change?
All in all, I think it was neat that, with two simple changes, we get things that are pretty darn close to Low-Tech, likely within a reasonable margin of error.


3. Comparison with Armors in GURPS High-Tech

The pyarmid article includes a few higher-tech materials, including Aramid Fabric, which is the main material behind modern ballistic armor. Unfortunately, in this case, I cannot reproduce the values found in GURPS High-Tech.

There wasn't much I could compare to with the available material list. I found the few ballistic armors, and assumed they were built with the Layered Fabric construction style (as ordinary Fabric would have given a penalty to impaling damage...)

The Concealable Vest come out pretty close, when built with the Layered Fabric construction style.

But it's the only one that matched the Armor Design's rule of having a x4 DR for piercing. The Assault Vest and Ballistic Legging have a DR of 12/5*, and that was first challenge. If I built the armors with DR 3, giving x4 = DR 12 vs piercing, I get the same protection against bullets, but less against a spear... I found I could live with that, but have no clue as to realism of that decision. That said, the weight was still way off, typically less than 50% of the listed weight in High-Tech.

Now, interestingly enough, if I use the Combining Gadgets rules and build in a Load-Bearing Vest and Plate Carriers (for a front and back large trauma plate; based on article in Pyramid 3/57 Gunplay I estimated at 1 lbs and $75 per pocket) into the vest armor, it actually winds up with values relatively close the the Assault Vest values.

So, we can match the Concealable Vest, and we can come close to rebuilding the Assault Vest (with DR 12/3*) if you get creative... but the the arms and legs will still be designed at half the weight of High-Tech.

Couldn't even come close to rebuilding the Bomb Disposal Suit. While the ballistics rules easily make the DR 20/5* match because of the x4 effect, a DR of 5 is beyond the maximum DR of 3 for an Aramid Fabric to remain flexible. Even ignoring that, we wind up with a cost and mass that are 1/3 of the values in GURPS High-Tech. So, presumably it's made of some other material... or the rules in the Armor Design just don't apply here the same way.


4. Ultra-Tech

As I said, I originally started working on this to expand the table. So below are the values I came up with. Note that I have no "realistic basis of comparison" here. I based them solely on their comparative values between each other in GURPS Ultra-Tech as opposed to any research into the possible theoretical material strength and density of the material. So, extrapolating from the table in the Armor Design article, and using the terminology from GURPS Spaceships for some materials, I came up with the following values:

Light Alloy (TL7): WM: 0.3; Cost: $45; DR/inch: 135; Max DR: 27; Notes: - ; Construction: Mail, Plate, Scale, Solid. (This includes very high-quality versions of aluminum or titanium)

Metallic Laminate (TL8): WM: 0.2; Cost: $91.5; DR/Inch: 202; Max DR: 40; Notes: - ; Construction: Mail, Plate, Scale, Solid.

Advanced Metallic Laminate (TL9): WM: 0.13; Cost: $165; DR/Inch: 303; Max DR: 60; Notes: - ; Construction: Mail, Plate, Scale, Solid.

Reflex Fabric (TL9): WM: 0.1; Cost: $100; DR/Inch: 18; Max DR: 9; Notes: BF; Construction: Fabric, Layered Fabric.

Replas Fabric (TL10): WM: 0.01; Cost: $124; DR/Inch: 18; Max DR: 9; Notes: FL*; Construction: Fabric, Layered Fabric.

Nanocomposite (TL10): WM: 0.09; Cost: $355; DR/Inch: 455; Max DR: 90; Notes: - ; Construction: Mail, Plate, Scale, Solid.

Nanoplas Fabric (TL10): WM: 0.08; Cost: $157; DR/Inch: 24; Max DR: 12; Notes: FL*; Construction: Fabric, Layered Fabric.

Nanoweave Fabric (TL10): WM: 0.08; Cost: $125; DR/Inch: 24; Max DR: 12; Notes: BF; Construction: Fabric, Layered Fabric.

Diamondoid (TL11): WM: 0.06; Cost: $750; DR/Inch: 683; Max DR: 135; Notes: - ; Construction: Mail, Plate, Scale, Solid.

Monocrys Fabric (TL11): WM: 0.05; Cost: $155; DR/Inch: 36; Max DR: 18; Notes: BF; Construction: Fabric, Layered Fabric.

Organic Armor (TL11): WM: 0.69; Cost: $15.50; DR/Inch: 34; Max DR: 7; Notes: - ; Construction: Mail, Plate, Scale, Solid.

Energy Cloth (TL12): WM: 0.03; Cost: $195; DR/Inch: 60; Max DR: 30; Notes: BF; Construction: Fabric, Layered Fabric.

Exotic Laminate (TL12): WM: 0.04; Cost: $1,500; DR/Inch: 1024; Max DR: 200; Notes: - ; Construction: Mail, Plate, Scale, Solid.
* L = Laser Ablative: The armor has a x6 DR vs lasers, but that additional DR is semi-ablative and will get burned away as it absorbs laser damage.


Again, I merely extrapolated with existing Ultra-Tech values, and have no research to what is "realistic". I'd appreciate comments here. Of note, they're based on stepping up from TL8 armor... so the same difficulties of making the mass accurate for TL8 armor in High-Tech are reproduced here with these items.

As a side exercise, I then went back and re-calculated the values of armor in GURPS Spaceship to match these values. It typically resulted in a two orders of magnitude increase in cost. It's arguably a more realistic cost to spaceships and vehicles.

From what I heard, GURPS Vehicle Design will include the official table for all of the above. I'm looking forward to it (mostly to build weapons and armors, not vehicles; as i did with the GURPS 3E version). But I intend to use these values until it comes out. But, would love feedback from others as to whether it makes sense... or whether you find it useful.

Last edited by Kallatari; 11-09-2013 at 09:36 AM. Reason: Error in math for new material, so redid most
Kallatari is offline   Reply With Quote
Old 11-02-2013, 01:15 PM   #2
DouglasCole
Doctor of GURPS Ballistics
 
DouglasCole's Avatar
 
Join Date: Sep 2004
Location: Burnsville, MN
Default Re: Pyramid 3/52 - Low-Tech Armor Design - Comments and Questions

Those bomb disposal units aren't terribly flexible, from what I can tell. So that might not be unrealistic.
__________________
The Deadly Spring "...probably the most infamous Pyramid article of all time."-Jeffro's Car Wars Blog
Gaming Ballistic: Home of Gaming Ballistic, LLC and my blog.
DouglasCole is offline   Reply With Quote
Old 11-02-2013, 01:45 PM   #3
chandley
 
Join Date: Aug 2004
Default Re: Pyramid 3/52 - Low-Tech Armor Design - Comments and Questions

Note that it will be quite the trick to make Mail out of really any kind of laminate. Laminate is several layers of (possibly different) material sandwiched together. Im not sure how you would go about making useful mail rings out of that. In fact, of the list you present, only Nanocomposite and possible Exotic Laminate (despite the name, because who knows what that stuff really is) might qualify for Mail construction type.

You could punch out rings from laminate, but your construction would look a lot more like scale or lamellar than mail. The Advanced Body Armor in High Tech is scale armor, if that helps at all.

Also High Tech set DR's based on "informed performance". They dont follow a system that I am aware of. Generally, the /5 came about as the DR of the fabric carrier against things like knives and baseball bats, and it was an eyeballing. Adjusting that number to fit the Low-Tech Armor Design assumptions probably isnt going to hurt anything, realism wise. Measuring the difference between a 5 damage spear thrust and a 3 damage spear thrust might be beyond our abilities.
__________________
My GURPS stuff
chandley is offline   Reply With Quote
Old 11-02-2013, 04:56 PM   #4
Anthony
 
Join Date: Feb 2005
Location: Berkeley, CA
Default Re: Pyramid 3/52 - Low-Tech Armor Design - Comments and Questions

Quote:
Originally Posted by chandley View Post
Note that it will be quite the trick to make Mail out of really any kind of laminate.
I can think of several ways to make mail out of laminates. However, I cannot think of any reason for doing so -- the reasons you use laminates are specific to plates.
__________________
My GURPS site and Blog.
Anthony is online now   Reply With Quote
Old 11-02-2013, 05:46 PM   #5
Kallatari
 
Join Date: Jan 2006
Location: Ottawa, Canada
Default Re: Pyramid 3/52 - Low-Tech Armor Design - Comments and Questions

Quote:
Originally Posted by DouglasCole View Post
Those bomb disposal units aren't terribly flexible, from what I can tell. So that might not be unrealistic.
So should we be suggesting an errata to High-Tech to remove the flexible? Curious if anyone on the playtest has thoughts on that.

Personally, I'd be willing to either fudge it and allow it to remain flexible, or, more likely, decree the armor isn't flexible. I don't mind that kind of change.

My real concern was the fact that it comes out to about 1/3 the cost and 1/3 the mass. Granted, cost is easier to hand wave in a given campaign ("we produce so few of them that we don't get economies of scale, thus the costs are higher"), but the mass bugs me. Going from 65 lbs that can hamper easily hamper someone to a mere 20 lbs (and thus possible to not even encumber a person) doesn't seem right to me.

Hmm.. going over High-Tech again, and seems I made a mistake. The DR 20/5 is front torso/everywhere else, not piercing/other. So, it's likely is some other material, as DR 20 exceed the Max DR for Aramid Fabric. For the fun of it, I made a suit with DR 20 front torso and 5 elsewhere, and that still leaves me at 50% mass, not to mention that it would give me DR (20 x 4 =) 80 vs bullets on the front torso.
Kallatari is offline   Reply With Quote
Old 11-02-2013, 05:57 PM   #6
Kallatari
 
Join Date: Jan 2006
Location: Ottawa, Canada
Default Re: Pyramid 3/52 - Low-Tech Armor Design - Comments and Questions

Quote:
Originally Posted by chandley View Post
Also High Tech set DR's based on "informed performance". They dont follow a system that I am aware of. Generally, the /5 came about as the DR of the fabric carrier against things like knives and baseball bats, and it was an eyeballing. Adjusting that number to fit the Low-Tech Armor Design assumptions probably isnt going to hurt anything, realism wise. Measuring the difference between a 5 damage spear thrust and a 3 damage spear thrust might be beyond our abilities.
That was my thought as well, which is why I didn't mind changing the DR of the assault vest in my modern counter-terrorists campaign to 12/3*. But flagged it in my comments anyway because it is a change if others want to go that route.

As with the bomb disposal, I'm more bugged about the mass. But, in all fairness, that "annoyance" (if you will) is all based on the assumption that the weight provided in GURPS High-Tech are accurate. Sadly, my knowledge of such real-life equipment is nil, and my quick searches of the internet have revealed that I don't know how to compare the "real world ratings" to GURPS rating, and have found weights across the board... I'm curious how High-Tech came about to a value, if anyone knows the answer?
Kallatari is offline   Reply With Quote
Old 11-02-2013, 06:29 PM   #7
Fred Brackin
 
Join Date: Aug 2007
Default Re: Pyramid 3/52 - Low-Tech Armor Design - Comments and Questions

Quote:
Originally Posted by Kallatari View Post
So should we be suggesting an errata to High-Tech to remove the flexible? Curious if anyone on the playtest has thoughts on that.
No, compliance or non-compliance with a design system of gear in a book about Real World equipment is not errata. If the design system disagrees with (accurate) Real World data the design system is wrong.

As to whether or not the bomb suit DR v. Impaling and similar attacks is accurate I doubt anyone actually knows. The armor is actually quite rare and very seldom if ever encounters attack by anything but explosions.

The playtest crew didn't include anyone with bomb disposal experience either. Or at least no one mentioned it.

As to the issue of the DX penalty I would suggest that the bomb suit is effectively a layered suit of armor and to see the rules on layering armor.
__________________
Fred Brackin
Fred Brackin is online now   Reply With Quote
Old 11-02-2013, 06:49 PM   #8
Kallatari
 
Join Date: Jan 2006
Location: Ottawa, Canada
Default Re: Pyramid 3/52 - Low-Tech Armor Design - Comments and Questions

Quote:
Originally Posted by Fred Brackin View Post
If the design system disagrees with (accurate) Real World data the design system is wrong.
I agree with you there. That's one of the reason's I started this post; to see how we can "fix" the design system.

But "Is this armor really flexible?" is a valid question. From my really quick internet scan, from what I see, people have died from explosions despite the armor not being penetrated, which suggests Blunt Trauma.

But rather than making the armor "Flexible", could that not have instead been addressed with a rule along the lines of collisions, where a full body impact in a collision renders all armors effectively Flexible and thus the wearer is susceptible to Blunt Trauma? (p.B431) So the armor could be non-flexible, but against an explosion it counts as flexible? (I'd even be more specific and say "crushing explosions")

Granted, that that would be a house rule and impact how all other armors work, so not sure the full possible side-effects of such a rule.

Quote:
Originally Posted by Fred Brackin View Post
As to the issue of the DX penalty I would suggest that the bomb suit is effectively a layered suit of armor and to see the rules on layering armor.
Hmm. That's certainly one way to address the bulkiness of the armor. And would explain why it has a base DR 20 which is over the so-called "Max DR." I like that.

Still doesn't fix the fact that I'd be at 50% the mass of High-Tech, though. (and 40% the cost, but I'm a bit less concerned about that; as you said, it's rare enough to justify a mark up)
Kallatari is offline   Reply With Quote
Old 11-02-2013, 07:05 PM   #9
Anthony
 
Join Date: Feb 2005
Location: Berkeley, CA
Default Re: Pyramid 3/52 - Low-Tech Armor Design - Comments and Questions

Quote:
Originally Posted by Kallatari View Post
But "Is this armor really flexible?" is a valid question. From my really quick internet scan, from what I see, people have died from explosions despite the armor not being penetrated, which suggests Blunt Trauma.
If your standard for flexible is 'explosions can kill people through it', all armor is flexible.
__________________
My GURPS site and Blog.
Anthony is online now   Reply With Quote
Old 11-03-2013, 07:48 AM   #10
Kallatari
 
Join Date: Jan 2006
Location: Ottawa, Canada
Default Re: Pyramid 3/52 - Low-Tech Armor Design - Comments and Questions

Quote:
Originally Posted by Anthony View Post
If your standard for flexible is 'explosions can kill people through it', all armor is flexible.
Not what I meant... sorry if it wasn't explained correctly.

Using an example, if I'm in a Plate armor, it's non-flexible. Someone hits me with a sword, club, spear, etc., it's non-flexible, and there's no Blunt Trauma. But if I fall down, fall off a chair, or walk into a wall, suddenly, by the Collision rules, my plate effectively becomes Flexible for determining the injury suffered from that, and I suffer blunt trauma. That's RAW (p.B431)

My true question is: why? I'm presuming this had to do with the fact that in a fall or collision the damage is spread across the entire body instead of in a localized area like a weapon's surface. In there is also likely some nod to trying to match realism in that such armors probably don't protect you as well in a fall and "you suffer injury even though the armor might not get penetrated." So it was decided to use the Blunt Trauma rules that already exist to achieve that effect.

If my theory as to the why is correct, I would argue that explosions meet the same criteria. They're spread across the whole body, and "you still suffer injury even if not penetrated". So, it's a combination of both factors, not just the fact that you suffer injury on its own, that could support Bomb Disposal Suits not being flexible... but still counting as so against explosions. That's the proposed house-rule/rule change.

And again, I admit this being all theoretical. I know nothing of those armors other than they're thick, heavy (30-40 kg is typical), and wearers aren't very mobile. Maybe their being Flexible is totally justified by reality as they do bend. Don't know. I'm just trying to reconcile/fix a Design Rule with real life... and throwing ideas around and asking questions.

Whether the Bomb Disposal Suit is flexible or not, to me, is a lesser concern than why I can't match the weight.

Being reading up more on it, and it seems those armors also include a lot of plastic in them as well... so my likely next step is to create a "Plastic" material entry, and then make a combination with Aramid Fabric to see what I can build. Hopefully that will resolve mass discrepancies (but again, thick Plastic is likely non-flexible, so same debate).
Kallatari is offline   Reply With Quote
Reply

Tags
pyramid 3/52

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Fnords are Off
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 08:22 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.