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Old 09-23-2016, 11:09 PM
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Default Game Mechanics. Thermobaric rounds.

Have any of you found or brewed your own game mechanics for depicting these weapons?
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Old 09-24-2016, 09:26 PM
mmartin798 mmartin798 is offline
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Construction and fuel mix will cause a lot of variation. Off hand I would say take the explosive weight, assume C4 and multiply the DPW by 3 to get the resultant blast plus a fireball of 1200C that covers the blast radius for 1-2 sec would be a good place to start if you needed something fast. I don't think the shockwave + vacuum effect really needs to be exploited. The larger DPW per unit mass is just simpler and gets the job done.

I may have to look more thoroughly into this later.
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Old 09-24-2016, 09:35 PM
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Originally Posted by mmartin798 View Post
Construction and fuel mix will cause a lot of variation. Off hand I would say take the explosive weight, assume C4 and multiply the DPW by 3 to get the resultant blast plus a fireball of 1200C that covers the blast radius for 1-2 sec would be a good place to start if you needed something fast. I don't think the shockwave + vacuum effect really needs to be exploited. The larger DPW per unit mass is just simpler and gets the job done.

I may have to look more thoroughly into this later.
See that is part of it....... Everything takes burn damage, if only a flash burn...... but, it is the nasty out then in shearing forces of the vacuum effect.

I was thinking of one set of damage for the explosion..... then more damage, possibly half that of the original DPW, as the atmosphere rushes back in.
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Old 09-27-2016, 09:11 AM
mmartin798 mmartin798 is offline
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See that is part of it....... Everything takes burn damage, if only a flash burn...... but, it is the nasty out then in shearing forces of the vacuum effect.

I was thinking of one set of damage for the explosion..... then more damage, possibly half that of the original DPW, as the atmosphere rushes back in.
So are you proposing a table similar to the RE chart for round composition for the two effects, i.e. ethylene oxide causes X1 then Y1 dpw, ethylene oxide plus aluminum powder does X2 then Y2 dpw, etc.?

This then questions is there a difference in effect for the two blast effects? They happen very quickly one after the other which is why I suggested a single larger value with an implied greater RE for the explosive to simplify the use. If there is difference, how does that manifest in the application of the damage? Something like you are inside an armored vehicle with weapon ports open that spares you from the initial blast, but the sudden pressure changes rupture ear drums and may cause other whole body damage?
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Old 09-27-2016, 09:59 AM
mmartin798 mmartin798 is offline
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Found this article that gives some general figures for FAE used by Russian forces in 2000. Need to think more about how this could work in game.

http://fmso.leavenworth.army.mil/doc...ir/fuelair.htm

Plus Global Security gives some general formulas for calculating distance to 1 PSI over pressure in this article. Using these might get us on the right track.

http://www.globalsecurity.org/milita...itions/fae.htm

Last edited by mmartin798; 09-27-2016 at 10:12 AM.
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Old 09-28-2016, 07:19 PM
Matt W Matt W is offline
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From wikipedia (Quoting the Defense Intelligence Agewncy)

"The [blast] kill mechanism against living targets is unique–and unpleasant.... What kills is the pressure wave, and more importantly, the subsequent rarefaction [vacuum], which ruptures the lungs.... If the fuel deflagrates but does not detonate, victims will be severely burned and will probably also inhale the burning fuel. Since the most common FAE fuels, ethylene oxide and propylene oxide, are highly toxic, undetonated FAE should prove as lethal to personnel caught within the cloud as most chemical agents."



I don't know if this helps, but the "Modern Firearms" website has this this description of the real-world 93mm thermobaric RPG-7 or RPO-A warhead

"The blast effect of the thermobaric / FAE RPO-A warhead,which contains about 2.2 kg of Fuel-Air Explosive is roughly equivalent to the blast effect of the 107mm / 4" HE artillery shell. Upon explosion, RPO-A warhead generates the cloud of high-temperature flame (blast) which is about 6-7 meters in diameter(blast radius 3 meters or more). The blast cloud lasts as long as 0.4 seconds, thus allowing for significant incendiary effect in addition to the massive pressure wave (typical HE explosion lasts much shorter)."

What rules do you need?

Last edited by Matt W; 09-28-2016 at 08:03 PM.
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Old 09-28-2016, 08:45 PM
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What rules do you need?
In my estimation..... Thermobaric rounds produce three effects in under a second...... burn, blast, and vacuum.

Burn... 1300 to 3000 degrees (exact amount?) So I think burn damage is appropriate.

Blast... the DPW does this. However, the shear (fracturing forces) is greater. There is a specific word for this in regards to explosive that is completely escaping me at the moment. So I was thinking that Thermobaric explosions should be more effective than normal explosives against hardened structures.

then Vacuum...... I don't know how to model this in game...... except to declare NPC dead on the spot.
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Old 09-29-2016, 06:47 AM
mmartin798 mmartin798 is offline
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Quote:
Originally Posted by ArmySGT. View Post
In my estimation..... Thermobaric rounds produce three effects in under a second...... burn, blast, and vacuum.

Burn... 1300 to 3000 degrees (exact amount?) So I think burn damage is appropriate.

Blast... the DPW does this. However, the shear (fracturing forces) is greater. There is a specific word for this in regards to explosive that is completely escaping me at the moment. So I was thinking that Thermobaric explosions should be more effective than normal explosives against hardened structures.

then Vacuum...... I don't know how to model this in game...... except to declare NPC dead on the spot.
The effects on personnel is extreme. People nearest the blast point that are not immediately vaporized experience an overpressure in excess of 14 PSI for over a second crushing them to death. A bit further out, burns and ruptured internal organs from the overpressure followed by the partial vacuum from the rarefaction do not kill quickly, but require extensive and expensive medical care to save. Still further they still get burns, but with moderate eye and ear protection and body armor can be spared extensive damage, through they still require medical attention. These effects are for the unenclosed detonation. Not something like the rounds with HEDP warhead in front of the FAE to punch a hole through armor so the FAE detonation can take place inside the tank or structure.
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Old 09-30-2016, 06:31 PM
nuke11 nuke11 is offline
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That's some serious firepower for the project to issue, but I guess since there is a flame thrower issued and those where banned under Protocol III (PROTOCOL ON PROHIBITIONS OR RESTRICTIONS ON THE USE OF INCENDIARY WEAPONS ) of the Geneva Convention.

What do you plan on using that with?
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Old 10-01-2016, 03:34 PM
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Soviets.....

There are several variations of thermobaric rounds as standard issue in the 90s.

This and I was thinking the FAE mine clearing round for some MARS unit.

Because..... there is a tradition in the modules of starting the PCs in some vehicle completely unsuited to the events and situations in the modules.


Plus, I want to beef up the Soviet threat in "Final Watch" and augment them ... maybe reinforcements that have arrived from Alaska or the Kamchatka peninsula.
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