Thermobaric bomb

[Jormonma]

My favourite villain is planting a thermobaric bomb in a building, but I have no clues about how to deal with it in the rules...

 

Here is my guess: Area of Effect attack with 4 separate effects:

 

1) energy RKA (6d6? maybe more?).

2) Double Knockback, making the people go against the walls and through them (that is, up to 11d6 normal damage).

3) Static overpressure destroys the walls anywhere. The building colapses creating more damage to people who went through the walls. No idea how much, but I guess is Explosion damage. There are no robots in my game, but if a robot were in the area the overpressure will destroy it for sure like an atom bomb.

4) Negative pressure; physical RKA 3d6 if anyone is still in the area (in case of a building is not probable, they were punched out).

 

Well, what do you think?

[RexMundi]

Re: Thermobaric bomb

 

Mm.....You are going to need to work out a way for the Thermobaric Bomb to get enough dispersal to actually be effective......There's actually a way you could turn the entire building into a thermobaric device.

 

I wouldn't waste time with RKA though. Piles of Dice! Only way to go but an RKA could certainly be a component once it gets going....couple of ways to build it actually. Most Thermobaric bombs are really big....seriously big ....but they do have them all the way down to a 40MM grenade now that can flatten a small one story building....

 

~Rex....goes to crunch numbers. Need more details though as to what type of building you want to flatten.

[shadowcat1313]

Re: Thermobaric bomb

 

do thermobaric bombs have the same problems with rain and wind as FAE bombs?

[RexMundi]

Re: Thermobaric bomb

 

do thermobaric bombs have the same problems with rain and wind as FAE bombs?

 

A Thermobaric Bomb IS an FAE (Fuel Air Explosive)......Wind and Rain not so much an issue unless you are talking Hurricane levels (and the size of the device and it's initial scatter charge set up, etc etc factor into it as well...). Atmospheric Pressure and Altitude though mean a lot....

 

~Rex

[Jormonma]

Re: Thermobaric bomb

 

Well, the idea is to plant the bomb in a floor. The building is like any office building and the bomb is disguised as a vending machine. The gas will cover enough room before the detonation, and I figure if this floor is wiped out the upper will fall also collapsing the building.

 

My concern is if anybody with Damage Resistance and Damage Reduction can survive the explosion, and if the collapse will affect people in the outside. Regular people in this floor are dead without any dice rolling needed, but I need to roll for this powered ones. So I need a guide about the damage this bomb can do.

[Sundog]

Re: Thermobaric bomb

 

The correct term is "massive". Inside the distributed mist the temperature hits thousands of degrees, but the real killer is the prsssure. The early FAE weapons they used in Veitnam for clearing landing zones in jungle areas literally liquefied the trees inside the prime zone.

However, as I understand it one of the advantages of thermobaric weapons is that the secondary blast zone is relatively small - damage falls off quickly away from the misted area. Thus, they can be used in built up areas with limited collateral damage while guaranteeing the target is utterly destroyed.

I would make a suggestion regarding the build: use two AOEs. First, a defined AOE for the Primary blast, and then an Explosive AOE radiating from that. I'm reallty unsure about the right dice, though.

[RexMundi]

Re: Thermobaric bomb

 

I'll have some good numbers around tomorrow or so (got games to do today). Converting the PSI numbers and doing a comparative check. I've got an idea on the build that REALLY takes advantage of some of the unique properties of a Thermobaric device, but I want to test it first. Then I'll post it. How big of an office building are you looking to Pancake?

 

~Rex

[CptPatriot]

Re: Thermobaric bomb

 

As others have said before, while the initial blast might pancake a floor, the big killer is the overpressure. If the blast does not destroy the walls when trying to fully expand to its blast radius, the pressure wave of the blast will try to escape out the areas that don't contain it, in that respect, the AoE will keep going out whatever openings are available and will likely increase the damage the people in the blast.

 

I would buy the initial RKA AoE(Radius, Explosion) and additional dice with more AoE, Only to do additional damage and expand the AoE Explosion Radius, proportional to the initial explosion blocked by walls.

[Jormonma]

Re: Thermobaric bomb

 

I'll have some good numbers around tomorrow or so (got games to do today). Converting the PSI numbers and doing a comparative check. I've got an idea on the build that REALLY takes advantage of some of the unique properties of a Thermobaric device, but I want to test it first. Then I'll post it. How big of an office building are you looking to Pancake?

 

~Rex

 

 

The floor building will be 50 m X 30 m. Is big. And has 30 floors, but the explosion will be in just one floor, may be the second or third.

 

According with Wikipedia the bomb has 430 psi. Can survive it a character with Damage Resistance?

[Orion]

Re: Thermobaric bomb

 

I feel this really calls for GM fiat, and not dice or rules. Given the potential damage, it would be entirely reasonable to declare that everyone inside the building dies. But, this being comics, a series of miracles occur and the characters just barely live. So, decide if anyone on the team could survive. If you want them to, then decide how badly you want them to be hurt. Next, figure out the average number of dice to get them that hurt, and use that figure.

 

If I were the GM, I'd end the session with the building blowing up around their ears. I'd then tell them that any no shows next week are dead characters and give an evil smile. Next week, I start by taking all character sheets and marking down the damage I want each character to have. After I give the sheets back to the characters, I tell them the smoke is clearing. Your hearing is coming back. Some of you are badly hurt - here is what you did to survive. I then ask what they do now? And the game starts from that point.

 

If all you want is a trap that beats them up, simply pick a number out of the air and make a blast that big. If you want it to be a story moment, forget numbers and just describe the effects.

[RexMundi]

Re: Thermobaric bomb

 

The floor building will be 50 m X 30 m. Is big. And has 30 floors, but the explosion will be in just one floor, may be the second or third.

 

According with Wikipedia the bomb has 430 psi. Can survive it a character with Damage Resistance?

 

The Bomb PSI varies per weapon, and it's probably better off thought of in Pascals for building flattening, but before I toss out the game builds I scribbled up for various Thermobaric Devices ranging from the 40MM to the FOAB....let's work with the 430psi load....

 

Say you got a big viking guy like myself, standing around eating a hotdog while the 430psi shockwave hits him in the mush. A Guy my size has a total Surface Area of around 2.68 sq meters. So, taking all that in the front, is roughly 1.34 square meters. That's using the Dubois and Dubois BSA conversion. So, there being 1,550 (roughly) sq Inches to a Sq Meter.....you get 2077 x 430 for 893,110 pounds of SPLAT! which equals around 14d6 Normal Damage give or take a d6 here and there. (I work in Construction so things like Floor Stresses and Crushing points and a lot of other boring stuff is still easy for me to visualize)....

 

So....Being that your typical building that you mentioned would most likely be in the 8 pd /10 ed / 5 body range (Reinforced Concrete let's say), a 14 d6 Attack is gonna do *Fires up the Awesome WP7 prototype a certain hero Board member was cobbling up. Well .....Best roll out of 5 was 19 body and 59 stun out of that. So some serious Pulverizing would occur. More so if you want to toss in Double Knockback and even Armor Piercing for the devices, AND, that's just the Physical Component.

There's a pretty significant temperature component as well ranging as High as 2200k for the initial ignition, and numbers from that to as low as a mere 650c depending on components and type of thermobaric device.....so you COULD, toss in another up 14DC worth of Ouch I'm on Fire as well .... You could scale around as well with the Explosives listed in the HSEG, Some good scaling and bad scaling in there but a functional base.

 

So, yes, enough Resistant Defense will survive it. The Fireball effect is the only thing I would use the Killing Attack damage for. Thermobaric go boom, building falls over.

 

~Rex

[Jormonma]

Re: Thermobaric bomb

 

Thank you, Rex, I will work with these guidelines.

I think one character can survive it easily, but the rest will be a bit damaged.

[RexMundi]

Re: Thermobaric bomb

 

Thank you, Rex, I will work with these guidelines.

I think one character can survive it easily, but the rest will be a bit damaged.

 

Yeah just don't forget in a multifloor set up like that you are going to get some pancaking. A Double 14 dc attack, one side physical and the other side energy is pretty much gonna flatten the building eventually. It may not happen all at once but it's gonna come down. A lot of that is gonna come from the crushing damage as piles of building now start trying to get closer to the ground. Damage from that is simply a matter of working out the mass and going for the crushing damage. So pretty much, under GM control, turn up the spigot as needed, apply other effects like electrical shock from high voltage lines, entangles from being stuck in rubble, negatives to rolls from the debris (Change Environment scale), Smoke and Darkness or even flash blinding from the explosion (Flash, Darkness with time, Change Environment etc).....

 

Lot of components.

 

~Rex