Talk:Thermobaric weapon

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[edit] Error over oxidisers

The article states:

"The weapon is initiated upon dropping or firing, and the explosive charge (or some other dispersal mechanism) bursts open the container and disperses the fuel in a cloud. The fuel undergoes aerobic reactions to mix with the surrounding gaseous oxidizers (H, H2O, CO and CO2), instead of atmospheric oxyge..."

This makes little sense. Hydrogen (H) is not an oxidiser but a reducer. The other compounds would only be considered to be oxidisers under exceptional circumstances if at all. --ManInStone (talk) 12:39, 14 January 2008 (UTC)

A few things to clarify: 1. The military classifies the power of an explosive by referencing against TNT, whereas TNT is considered a 1 on the scale. Explosives having a number higher than 1 are considered more powerful than TNT, those with a lower number, less. RDX has a TNT equivalency of 1.5, making it 1 ½ times more powerful by weight. One of several different tests is used to measure the explosive. Simply using a ratio of yield to weapon weight is not an effective means of measuring an explosive’s power. That being said, I don’t think thermobaric explosives lend themselves well to being measured through TNT equivalency. This is due to the lower, and much longer pressure wave of the explosive. 2. Current thermobarics do not need to rely on the atmosphere for the oxidizer, it is part of the explosive mixture. Older FAE weapons did use the atmosphere, but this caused the weapon fuzing system to be relatively complicated, since the fuel had to be dispersed and allowed to mix with the ambient air before being detonated. 3. Thermobarics are especially effective against closed spaces because the extended positive pressure wave is more pronounced when in a confined area. The pressure causes the alveoli in the lungs or the lungs themselves to collapse. Eardrums will also burst at lower pressures. 4. Thermobarics were definitely used in Vietnam. The CBU(Cluster Bomb Unit)-55 was carried by helicopter and designed to be used as a means to clear an area for an LZ. The CBU-55 was dropped using a parachute to ensure proper orientation. 3 submunitions were contained in the CBU. A probe with a pezio-electric crystal on the tip was extended during free-fall which initiated the firing train when it contacted the ground. First, a burster charge caused the ethylene oxide to “spray” out and mix with the atmosphere. At the same time, 3 detonators were expelled and would detonate after just a few milliseconds, causing a detonation. One test that the Army performed used monkeys strapped to high chairs who were then subjected to the blast. Not a video for the faint of heart. —Preceding unsigned comment added by 198.243.13.118 (talk) 04:27, 10 February 2008 (UTC)


[edit] Yield

These weapons are generally described as being very powerful but unfortunately this has not been quantified in this article in any way. The article describes the mechanism and effects but this means very little without details of the yield. This page really needs to be modified to describe the yields of these weapons. Furthermore a description of the yield to weapon weight would be useful for making comparison with other weapon systems. For example the data could be listed in a table to allow comparison as follows (the figures shown below are just approximate and a very wild guess for the Fuel Air Bomb).

Bomb Weapon weight (tons) Yield (tons of TNT) Yield to weight ratio
USA Davy Crockett nuclear bomb 0.023 500 21,739.1
USA Fat man nuclear (Hiroshima) 4.6 21,000 4,565.2
USA Mark 21 Thermo nuclear 21 15,000,000 714,285.7
UK WE 177B Nuclear 0.46 450,000 978,260.9
UK Grand Slam conventional WWII 10 4 0.4
Russian Father of all bombs (FAE) 30 60 2.0

The above (could someone help lay this table out better please? -- Done! Vrmlguy 09:54, 13 September 2007 (UTC)) shows that both the Fuel Air Bomb yield and the ratio is relatively high for a non-nuclear bomb type. But these values are generally very small when compared to nuclear bombs. The media have often described these devices as being as powerful as small nuclear bombs but in actual fact this is not a simple comparison. Such claims are usually just a bit of hype.

Weapon weight is important when assessing the deliverability of the weapon. For example it is possible that only the Russian backfire bomber is large enough to deliver the new Russian Fuel Air Bomb, while the Davy Crockett can be delivered by a recoilless gun operated by a three man team on foot.

Some discussion of the mass saving of the agents of the weapons due to the use of ambient oxygen could be given. I would expect the mass of fuel used in such a weapon to be about half the mass of conventional explosive for an equivalent yield.

Discussion of the effects (such as brisance, blast, etc) need to consider that the size of the explosion which will Influence this as well as the mechanism. For example a large explosion will have a reduced shock to blast ratio compared to a smaller bomb at a distance of comparable blast.

Very large weapons (against non-hardened targets) tend to use proximity fuses to achieve an air burst which will reduce the maximum over pressure at ground zero but will maximise the area of destruction (though reduced overkill). However, I would imagine that all Fuel Air Bombs are air bursts because of the firing mechanism. --ManInStone 14:29, 12 September 2007 (UTC)

I did some calculations based on using Ethylene Oxide as a fuel, which could be added to the CALCULATIONS section. The empirical chemical equation for its complete burn (deflagration) is:

2(C2H4O) + 5(O2) → 4(CO2) + 4(H2O)

where the molecular weight for two molecules of ethylene oxide is 216.104 and the five molecules of oxygen is 160. This means that using ambient oxygen, as the oxidiser will reduce the ingredients of the weapon weight by 43%. In other words this increases the yield by a little over a factor of two! The lightest fuel which could be used would be hydrogen (which may not be a practical fuel) which would give an upper limit on the weight saving of an Fuel Air Bomb of about 80% (or five fold increase in yield). There are a number of assumptions and generalisations involved in the above, but it gives a rough idea of the yield to weight ratio advantage of the fuel air system over a conventional explosive. ManInStone



UH OH. The Daisy Cutter page says it's not thermobaric/fuel-air. Can we get a decent source for the claim that US used fuel-air in the Viet Nam conflict? I'm leaving my edits as they are for now. I know I've got the nuke-vs-fuel-air info straight, I have done my homework on that and can substantiate. I also think I'm on solid ground about the nomenclature note. Sorry/Thanks in Advance.

Is this the sort of thing you are looking for?
http://www.nawcwpns.navy.mil/r2/mj/ar/FAEELMC.htm
Daisy Cutters are totally unrelated bombs that use the same sort of blasting slurry that miners use. Oralloy 17:23, 5 December 2005 (UTC)

I'm not entirely clear on the explosion physics. Can someone verify and explain? As I understand it the process is this: A "small" explosive charge disperses the fuel through a large amount of air. A second explosive charge (different in some way that's not too clear) ignites the fuel-air mixture causing a large explosion. Once outside the initial cloud, this explosion pushes a shockwave of very hot gas away. Damage arises from the heat and overpressure of this shock wave striking objects. This shock wave carries away almost all the gas, even beyond the thermal expansion, so it leaves behind a vacuum which tends to break open sealed containers (that survived the overpressure?). Presumably the heated gas then rises, leading to an inrush of air along the ground, leading to fires. Andrew 04:39, Apr 13, 2004 (UTC)

What you've described is one type of fuel air explosive (though I don't know if the vacuum part is true).
Some other types do not disperse the fuel before igniting it, but just set off an explosion that both ignites and disperses the fuel simultaneously.
Here is an old Air Force article (available through Internet Archive) that mentions these types:
http://www.af.mil/news/Apr2002/n20020409_0546.shtml
http://www.af.mil/news/Apr2002/n20020409_0546.asp
Both links lead to the same story. I have varied effects with them at Internet Archive. Sometimes both links get results; sometimes only one or the other works.
And here is a link (also available through internet archive) to a story about the development of America's "single stage" type thermobaric bombs:
http://www.sunspot.net/bal-te.bz.bomb04aug04.story Oralloy 17:23, 5 December 2005 (UTC)

Why is a thermobaric explosion more dangerous to people in foxholes or body armour? Enquiring minds want to know.

[edit] It's wrong all around!

Thermobaric weapon’s effect is based on the fact that the detonation speed rises dramatically when it passes from solid (TNT) to dispersed (air) explosive material. In thermobaric weapons there actially IS detonation involved.

In fuel-air explosive, on the other hand, there is NO detonation. The fuel cloud just deflagrates, producing high-pressure cloud, that travels at sub-sonic (important!) speeds. Its brisant effect is negligible. It just burns out anything on its way and also kills personnel by leaving sort-of-vacuum behind it: imagine a pipe in which there’s an explosion – the air rushes out, and sort-of-vacuum happens in the middle of it; the same happens with FAE, but in 3D. After the fuel is dispersed, it’s lit from inside either by a second explosion, or it lights up by itself (auto-ignition).

The clear distinction between EBM, Thermobaric and FAE is described here, Annex "C" (PDF, 280KB).

Also - Russian military say, that there’s a well-known Tando-effect, named after a Chechen village of Tando, which was completely burned down by a lone Russian helicopter shooting thermobarric weapons. So now, when a single helicopter appears over a Chechen village it creates panic no less than a squadron of bombers.

Thanks for the update. Hm -- if you have a chance, could you delete the offending sections of the article? Then we can start a new one on fuel-air explosives. jdb ❋ 01:21, 11 Feb 2005 (UTC)
I have added a link with comprehensive explanation of thermobaric weapon effect, and removed nonsense about vacuum.Serg3d 08:25, 14 Sep 2005 (UTC)
This page is completely wrong. There is a huge difference between thermobarics and FAEs. They are not the same and need two different articles. I am neither a chemist or physicist, so I wouldn't feel comfortable rewriting, since this stuff is very technical. But the long and short of it is that thermobarics detonate more slowly but over a longer period of time than conventional explosive compounds. The above explanation of FAEs (deflagration followed by high pressure cloud) is correct. Thermobarics are what they are due to the chemical composition of the explosive compound. FAEs are what they are due to the mechanical process of weapon. For thermobarics, think of a graph with time on the x-axis and overpressure on the y-axis. with a normal explosive compound such as TNT, C-4, RDX, ANFO, there is a very high spike in overpressure that very quickly drops. "thermobaric" weapons have a lower overpressure at the moment of detonation, but the level of overpressure decreases much more slowly than a traditional explosive compound. the shape of a thermobaric explosion on the graph would be a semi-circle rather than a spike. i'm no chemist or explosives expert, but the reason is that coupounds that create a thermobaric effect detonate much more slowly, but for a longer duration. Like FAEs, thermobarics have reduced brissance, but increased overpressure (so they might not knock over your house/bunker if it's made out of reinforced concrete, but they'll turn your internal organs into jelly). The thing about the Russian helo taking out the entire village is likely because they were little houses, poorly constructed, and no more durable than the human body, which is very fragile.
And the so-called "Daisy cutter", the BLU-82, is neither an FAE nor a thermobaric, but a conventional explosive (just a very big one. However, it does have some slightly thermobaric effects. This page needs work by someone who knows the physics and chemistry, or by a real explosives expert. I am not one, but only trained well enough to know to run away as fast as possible. BTW, this thermobarics as "baby nukes" stuff is total nonsense. Nukes, even small ones, are several orders of magnitude more powerful than the largest thermobaric weapons that have ever been built. It's not even close. Binkymagnus 01:50, 2005 Apr 16 (UTC)

I agree - themobaric weapons usually consist of a central HE surrounded by fuel rich HE, so the post initial detonation reaction with atmospheric air may increase blast wave duration. FAE's are the oldest term for Fuel Air Explosives, and should be separate from Thermobaric weapons, as they aren't neccesarily the same, although a FAE may be considered a thermobaric, it doesn't have to be - it doesn't have to have heat as a primary means of destruction. —Preceding unsigned comment added by 87.51.151.27 (talk) 18:39, 25 September 2007 (UTC)

[edit] Strange Quote

It read:

"Blust create negative overpressure, enough to have human bodily lifted and thrown."

This was based on a quote from the linked PDF:

"The negative phase results in a reversed-blast wind and causes human targets to be bodily lifted and thrown."

[edit] legality of fuel air explosives

will a short exploration of the legality vis a vis international humanitarianlaw tomorrow.


The Russian use in urban areas to terrorise Chechnya, violated intl law. The weapon should not be used in civilian areas. thx Opuscalgary 19:42, 15 March 2007 (UTC)

Wrong. 68.83.210.47 (talk) 09:49, 2 April 2008 (UTC)

[edit] In Humane

Somewhere I believe I read that FAE's where going to be constituted as inhumane, could anyone confirm this?

Ever have you seen a "humane" weapon? --jno 11:58, 6 June 2006 (UTC)

[edit] Fiction section is wrong

In C&C Generals the MOAB is dropped from a B-3, not a B-2, which is a new platform which is not widely publicised. Also, the Fuel Air bomb featured is a BLU-82, and as such is dropped from the back of a C-130 Hercules. However, I don't want to change it since there is no wikipedia article on the new B-3. --The1exile 18:43, 2 March 2006 (UTC)

[edit] thermo-baric: heat & pressure

My understanding:

A thermobaric weapon is anything who's main damaging effect is heat and pressure in contrast to mechanical impact/fragmentation.

Instead of optimizing the explosion’s characteristics to throw fragments, which i assume takes a quick sharp pressure pulse, go for lower longer and hotter. spreading out the pressure pulse-> exposing targets to the high pressure for longer -> causing more damage than a sharp pressure spike would have? Same energy, but more momentum transfer-> tossing people around and destroying buildings

(a lot like small arms ammunition, compare a 5.56 rifle round to a desert eagle .50AE, both have about the same energy, but the pistol round has more than twice the momentum.)

The above makes no sense, because the momentum (mass times velocity) is the total energy of the missile.--ManInStone 15:09, 12 September 2007 (UTC)
Not so, momentum is mass times velocity, kinetic energy is one-half the mass times the square of the velocity. See, for example, this page. That said, I think that the bullet has more energy, so the original paragraphs above have the terms reversed. --Vrmlguy 10:10, 13 September 2007 (UTC)

The 'daisy cutter' and 'MOAB' both use explosive slurries, look at the video the fireball is so big people have confused it with a small nuclear weapon, heat and pressure.

Fuel air explosives are also thermobaric weapons.

fuel air animation

In most explosives everything necessary for the reaction is contained inside. In fuel air explosives all you need is fuel, oxidizer is provided by the air, so the same power can be achieved with a smaller package. Fuel air explosives are very sensitive to their dispersion-> weather can play a big factor in the results. Modern thermobaric weapons are moving towards solids instead of liquids and because the technology is improving and we can get those same, powerful blast effects from a single charge... wired describes thermobaric bombs as being "under oxidized". It sounds to me like it's a continuum from un-oxidized to fully-oxidized..

A better description is given here saying "Highly metalized standard high explosives meet the definition of thermobaric composition" "Most thermobaric materials require 3-6 lb of air per lb" It also has some nice graphs comparing pressure and temperature across time for C4 and a thermobaric explosive.

This whole thing about 'vacuum bombs' seems to me to be a lot of hype. Under oxidized -> burns oxygen. Is this enough to really suffocate anyone? The wired article, for example, had a lot of obvious pseudo-science garbage in it...

The other interesting bit is from wave mechanics, the amount of energy reflected or transmitted from a pressure wave hitting a change in materials depends on the difference in density-> air to stone is a really big difference-> most is reflected keeping the energy from the blast inside a cave (forming a mach stem?) instead of transmitting it out into the surrounding rock. If a tunnel turns a fragment will hit the wall and stop, a pressure wave will turn with it, following snaking tunnels and not reducing much in power.

The US has used some thermobaric 40mm grenades "xm1060" in Afghanistan with good reviews. it also plans on using them in the oicw/xm29/xm25 and OCSW 25mm.

They're also making rounds for the smaw SMAW-NE with more good reviews, and pictures of the destructive effects on buildings. they're also considering retrofitting all the obsolete m-72's.

Also hellfire missiles , blu-118

(personal opinion) Human rights violation? It's new and more effective, that tends to make people react. Is it any worse than getting shot? Or blown up with conventional explosives? Do you think a soldier in that situation cares about much more than survival? (/personal opinon)

[edit] urban legends

  1. Soviets have used conventional incendiary weapon against Chineese, which can provide a sort of fuel-air effect when used massively (note on Drezden is ok) --jno 11:50, 6 June 2006 (UTC)
  2. The noted RPO-A is a flame thrower. Just by its name: RPO stand for "Ruchnoy Pekhotny Ognemet" or "handleld infantry flame thrower". Better soviet/russian sample would be, say, TBG-7 grenade for RPG-7 launcher. --jno 12:02, 6 June 2006 (UTC)

The RPO-A is not really a flamethrower. It's a rocket propelled thermobaric grenade[1]Dwane E Anderson (talk) 14:52, 18 March 2008 (UTC)

[edit] humor

BTW, I wonder, if there is an english rumor similar to widely published (by press, seriously!) russian joke about "vacuum bomb" filled with "liquid vacuum", which is, being splashed out, decreases the pressure and affects the buildings and personnel? --jno 11:55, 6 June 2006 (UTC)

It not exactly humor, as it bears some truth. That description matches some of the munition that I have seen used in RPG's. While similar to thermobaric rounds, they differ in the fact that they create low pressure conditions. --Turbinator 18:42, 11 January 2007 (UTC)
Oh, my God! Liquid vacuum is "some truth"? Is PRG now considered as infosource? How about the course of physics from elementary school? --jno 07:07, 12 January 2007 (UTC)

[edit] Fiction section is huge

Maybe just move it under, say Thermobaric weapon/In Fiction? --jno 11:40, 19 July 2006 (UTC)




[edit] =========== Sentence deleted ==================

This sentence has been deleted: "Allegations were made in Lebanese media that Tsahal had used vacuum bombs during the July 2006 bombings of Lebanon" This should be an encyclopedia not an allegation list. Encyclopedic content must be verifiable


[edit] Original Research

  • Can the "Original research" tag be removed now? It's not clear to me what is being referred to as original research or unverified in the tagged section. If the editor who attached the tag could comment that would be great. If I can get a consensus that it is no longer required I will remove it forthwith. User:Jaganath 21:43, 08 August 2006 (UTC)
I see no OR as well. --jno 09:42, 9 August 2006 (UTC)
  • OK, I will provisionally remove the tag and then if anyone can see a section where it is more appropriate it can be re-instated if necessary.--User:Jaganath 18:07, 09 August 2006 (UTC)

[edit] Suitable against "soft targets"?

"...makes fuel-air explosives useful against soft targets such as minefields, armored vehicles, aircraft parked in the open, and bunkers."

That sentence includes pretty much everything but the light infantry. I wouldn't exactly call bunkers "soft targets" myself. Someone please clarify that one. --ZeroOne 14:09, 19 August 2006 (UTC)

It has now been changed to "...makes fuel-air explosives useful against hard targets such as minefields, armored vehicles, aircraft parked in the open, and bunkers."

I'm not sure that aircraft parked in the open are hard targets.

[edit] Dad of all bombs

considering that Russia has just demonstrated a very powerful thermobaric bomb, should this article be added to Weapons of Mass Destruction?--190.74.124.4 00:18, 12 September 2007 (UTC)

No, they aren't WMDs and they aren't really even comparable to WMDs. At best they are similar in sheer pressure alone to the tiniest nukes but they can't be scaled up to do anything like "mass destruction" (they can't destroy a city like even a WWII-sized nuke could do). If you added thermobaric bombs you might as well add car bombs to the list of WMDs. (No, I am not proposing that as a reasonable thing to do.) --24.147.86.187 (talk) 03:08, 23 November 2007 (UTC)

A WMD is defined as a nuclear, biological or chemical weapon, and the potency of the weapon is irrelevant to its description. Chlorine in your drinking water is a WMD, whereas the guns you own are not. --The Four Deuces (talk) 08:50, 30 November 2007 (UTC)

Where did you get that definition from? It doesn't match the Wikipedia page Weapons of mass destruction, which defines it by its potency. (Also, chlorine purifies water; surely it's only a weapon if it is in a high conceentration?!?) LachlanA (talk) 23:10, 13 January 2008 (UTC)

[edit] Concerned about an external link

i think that the external link: "animation" (3rd last) should be removed because it redirects the user to www.rotten.com which has a lot of gore and pornographic content, not visible in the animation provided but in text links at the bottom of the page. the animation shows the process of the thermobaric weapon, but there are better animations in the internet.Gcancelado 22:21, 25 September 2007 (UTC)

I agree. Perhaps someone with technical expertise could create a copy or something and upload it directly to Wikipedia. That would be more in keeping with policy anyway, in my opinion. 74.209.1.63 03:59, 1 December 2007 (UTC)

[edit] Vapor cloud explosion

The term "Vapor cloud explosion" redirects to this page. However, VCE's are not restricted to weapons, they are a common hazard in many commercial industries, and are a subject of industrial fire protection engineering. This term should direct to it's own page, Vapor cloud explosion. I'm not sure how to do this. Fireproeng 07:01, 8 November 2007 (UTC)