Car-Bomb Damage

[Digganob]

Can anyone give me an approximate GURPS damage value for a car-bomb explosion?

Now, I can easilly figure the damage needed to destroy a car (By using the chart on page B415, and assuming an SUV with 68 HP and 5 DR). But then, how much more damage will the explosion of the car's fuel tank add? Will it be more or less than what it absorbed from the initial bomb-blast? Should I add fragmentation?


Notes:
1) It's for a Supers game, so it doesn't have to be perfect. But, it's a semi-realistic Supers game, so I would like to be at least pretty darn close.
2) The bomb will probably be C4 attatched to the gass-tank.
3) The damage value of the actual bomb is less important than the total damage of the vehicle's explosion, as PCs just might be standing near one when it goes.
4) The intention of the bomber is to kill the driver inside the car, and anyone standing within 5 yards or so.

[vicky_molokh]

Originally Posted by Digganob

Can anyone give me an approximate GURPS damage value for a car-bomb explosion?

Now, I can easilly figure the damage needed to destroy a car (By using the chart on page B415, and assuming an SUV with 68 HP and 5 DR). But then, how much more damage will the explosion of the car's fuel tank add? Will it be more or less than what it absorbed from the initial bomb-blast? Should I add fragmentation?

According to VE184, gasoline explodes for 6d×15 damage per gallon, hydrogen for 6d×10 per gallon, rocket fuel for 6d×25 per gallon. I hope you're using a mundane car, not a rocket-fitted batmobile. :)

[Grayson]

Ouch! That is definitely going to leave a mark!

[Mgellis]

To convert this to 4e damage, you can use the following formula...

4e damage = 6 x square root (3e damage/6)

So, 6d x 15 cr ex for one gallon converts to about 6d x 4 cr ex.

Assuming 10 gallons in the tank, you would have 6d x 150 in 3e damage, converting to about 6d x 13 in 4e damage. The blast from the C4 will just be combined with this, or maybe it would push the damage up to 6d x 14 or 6d x 15, but if you've ignited 10 gallons of gasoline, you've got a pretty fierce explosion to worry about.

Using the rules in Basic Set, pp. 414-415, the blast could injure people to a radius of about 25-30 yards.

But the real damage from a car bomb will is likely to be caused by fragments...we're probably talking about 10d cutting damage here, and that will extend 50 yards out from the blast. The odds of being hit at 40 or 50 yards are low; however, if you are hit, you're in serious trouble.

I hope this helps.

Mark

Originally Posted by Molokh

According to VE184, gasoline explodes for 6d×15 damage per gallon, hydrogen for 6d×10 per gallon, rocket fuel for 6d×25 per gallon. I hope you're using a mundane car, not a rocket-fitted batmobile. :)

[DouglasCole]

Originally Posted by Mgellis

To convert this to 4e damage, you can use the following formula...

4e damage = 6 x square root (3e damage/6)

So, 6d x 15 cr ex for one gallon converts to about 6d x 4 cr ex.

Assuming 10 gallons in the tank, you would have 6d x 150 in 3e damage, converting to about 6d x 13 in 4e damage. The blast from the C4 will just be combined with this, or maybe it would push the damage up to 6d x 14 or 6d x 15, but if you've ignited 10 gallons of gasoline, you've got a pretty fierce explosion to worry about.

Using the rules in Basic Set, pp. 414-415, the blast could injure people to a radius of about 25-30 yards.

But the real damage from a car bomb will is likely to be caused by fragments...we're probably talking about 10d cutting damage here, and that will extend 50 yards out from the blast. The odds of being hit at 40 or 50 yards are low; however, if you are hit, you're in serious trouble.

I hope this helps.

Mark

In order to get the full blast out of gasoline, you have to disperse it. I would expect that most of that gas would BURN, not explode. I might assume ten gallons would get, basically ONE gallon of exploding gas, and nine gallons of burning residue (additional fragment damage, but BURNING instead of piercing).

Granted, that's a hunch, and I'd be intrigued to hear real-world data.

[VadersFear]

Well, I do think that realistically, the tank shouldn't matter, because a full tank will just burn and not explode, at least not in a cinematic bang.

If it is only partialy filled (1/3 or something), it is different, but nothing like a car bomb.

How much C4 would you put in to destroy the car?
2 pounds should be cool, better more, but I don't have the stats with me though...)

And fragmentation should deffinately be added!

[Wicked Lurker]

Sorry, stupid OT question..
Why is there a conversion from 3e damage to 4e damage necessary?
Hp ammount (except that they are now based on ST) and survival is pretty much the same as in 3e .. no?

[vicky_molokh]

Originally Posted by Wicked Lurker

Sorry, stupid OT question..
Why is there a conversion from 3e damage to 4e damage necessary?
Hp ammount (except that they are now based on ST) and survival is pretty much the same as in 3e .. no?

Because 3e applies DR^2 vs. explosions, while 4e lists explosion damage as SQRT(REF*mass).

[Bruno]

Originally Posted by Wicked Lurker

Sorry, stupid OT question..
Why is there a conversion from 3e damage to 4e damage necessary?
Hp ammount (except that they are now based on ST) and survival is pretty much the same as in 3e .. no?

No, the value of HPs away from human normal has changed radically, meaning that damage away from ~10 HP has also changed.

Take an elephant. 3e, used to have around 250ish HPs. 4e, elephants have 45. Thats a HUGE change.

[Nex]

Ah, I was unsure about that one as well, thanks!