Kinetic Energy to GURPS damage

[Stonewolf]

I'm trying to find a good equation or other system to convert damage done by a kinetic energy weapon or other weapon system to damage in GURPS. I have methods for converting nearly any projectile of a given material and muzzle velocity to kinetic energy in joules. What I need is a way to move from physics to GURPS.

[lexington]

Originally Posted by Stonewolf

I have methods for converting nearly any projectile of a given material and muzzle velocity to kinetic energy in joules.

Nearly any? What projectiles have you found that have no mass or velocity?

Originally Posted by Stonewolf

What I need is a way to move from physics to GURPS.

sqrt(KE^1.04/Xsect^0.314)/13.3926

Xsect is the area of a cross section projectile at its largest point (the base of a bullet, the center of a musket ball) in square meters. This was all worked out by Douglas Cole:
http://www.sjgames.com/pyramid/sample.html?id=2794

[DouglasCole]

PM me with an email address and I'll email you the spreadsheet I use to save you from making one yourself.

[Stonewolf]

[QUOTE=lexington;1105990]Nearly any? What projectiles have you found that have no mass or velocity?

Thanks for the equation. And by nearly any, I mean through on of several modeling methods I can compute the mass, muzzle energy and therefore kinetic energy either at the muzzle or at a given range. Its just ballistic physics.

[lexington]

Originally Posted by Stonewolf

Thanks for the equation. And by nearly any, I mean through on of several modeling methods I can compute the mass, muzzle energy and therefore kinetic energy either at the muzzle or at a given range. Its just ballistic physics.

So are you trying to build weapons that are dramatically divergent from from ones that really exist? I've done pretty well using that equation along with the numbers that armorers claim for their bullets.

[Stonewolf]

to Lexington

Not at all, I'm just coming at things from a different direction. Lets say I want to figure the numbers for a coil gun firing a 6.5mm 200 grain iron spitzer-boat tail projectile at 4500 feet per second. I can figure the KE on that. From there I need to convert to GURPS. I haven't seen the equation you gave me before. The Pyramid article you referenced is looking very nice so far.

[Darekun]

Originally Posted by lexington

sqrt(KE^1.04/Xsect^0.314)/13.3926

That has been bugging me for a while; wouldn't it be simpler like this:

(KE^.52/Xsect^.157)/13.3926

?

[DouglasCole]

Originally Posted by Darekun

That has been bugging me for a while; wouldn't it be simpler like this:

(KE^.52/Xsect^.157)/13.3926

?

True enough. It was an artifact of two things: one, the way I set up my model was to start with sqrt(KE^a/Xsect^b), and starting my solver with A = B = 1. The hope was that they'd be close to that.

Secondly, we often talk about penetration being about equal to sqrt(KE), based on a lot of good physics. I wanted to set up my equations such that it would be pretty apparent if my model was deviating from that expectation.