Traveller: The New EraTraveller_TNE Yahoo Groups Archive, 2005–2020

Thread: [Traveller_TNE] How to calculate damage from a rail gun (JC)

2 posts.

joel ·

How to calculate damage from a rail gun (JC)


Hi...

How would I go about calculating how much 'damage' a rail gun could do to
the hull of a starship?

Eric Henry's fantastic spreadsheet "Mass Driver" makes this possible, easy
and accurate.  (Thanks Eric!)

If I had a 10kg mass, with an exit velocity of 10,000 m/s (fantastically
high, I know), and the weapon/barrel length is 60 metres, I'd be able to
inflict 500  megajoules of damage onto the target.

Now... How do I reflect this energy transfer to the hull of a starship?

Let's say the hull is made from a metal (we'll use Titanium):
Melting Point--------:  (unknown)
Density      g / cm^3-----: 4.54
Atomization kj / mol-: 468.60


So, the bullet is fired at our target ship and hits!

500 MegaJourles of energy (kinetic/heat, right?) is transferred onto an area
5 cm across.

How do we determine if the hull if breeched?
Does the section of hull simply evaporate?

I'll assume the bullet disintegrates upon impact (more than enough energy is
transferred to the bullet as well), so clean "through and through" shots
aren't  likely (unless you had some really dense bullet material??  Anyone
care to suggest such a material?)

Thanks to everyone in advance...

-Joel

joel at mega-traveller dot com


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shadow ·

On 22 Jan 2006 at 11:05, wrote:

> How would I go about calculating how much 'damage' a rail gun could do to
> the hull of a starship?
>
> Eric Henry's fantastic spreadsheet "Mass Driver" makes this possible, easy
> and accurate.  (Thanks Eric!)
>
> If I had a 10kg mass, with an exit velocity of 10,000 m/s (fantastically
> high, I know), and the weapon/barrel length is 60 metres, I'd be able to
> inflict 500  megajoules of damage onto the target.
>
> Now... How do I reflect this energy transfer to the hull of a starship?

Well, a quick rule of thumb is that one megaton of TNT is 4.2e15J.

So one kiloton is 4.2e12, and one tonne is 4.2e9. Which makes 1 kilo
4.2e6. So you've done the equivalent of setting off 119 kilos of TNT.

Only a lot more concentrated.



--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com



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