New in Iraq, thermobaric rounds

[Jacks Complete]

http://www.defensetech.org/archives/001944.html
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<h3 class="title" style="text-transform: uppercase;">Marines Quiet About Brutal New Weapon</h3>

<p>War is hell. But it’s worse when the Marines bring out their new urban combat weapon, the <a href="http://www.talleyds.com/Product%20PDF%20flyers/SMAW-D%20NE-InfoPaper-10-03.pdf">SMAW-NE</a>. Which may be why they’re not talking about it, much.</p>

<p>This is a version of the standard USMC <a href="http://www.fas.org/man/dod-101/sys/land/smaw.htm">Shoulder Mounted Assault Weapon</a> but with a new warhead. Described as NE - "Novel Explosive"- it is a <a href="http://www.wired.com/news/conflict/0,2100,58094,00.html">thermobaric</a> mixture which ignites the air, producing a shockwave of unparalleled destructive power, especially against buildings.</p>

<p><img align=right img alt="smaw-ne sequence.JPG" src="http://www.defensetech.org/images/smaw-ne%20sequence.JPG" width="315" height="147" hspace="10" vspace="5" />A post-action report from Iraq describes the effect of the new weapon: "One unit <a href="http://www.globalsecurity.org/military/library/report/2003/oif_mcsc-field-report_apr2003.doc">disintegrated a large one-storey masonry type building with one round</a> from 100 meters. They were extremely impressed." Elsewhere it is described by one Marine as "an awesome piece of ordnance."</p>

<p>It proved highly effective in the battle for Fallujah. This from the <a href="http://www.mca-marines.org/Gazette/"><em>Marine Corps Gazette</em></a>, July edition: "SMAW gunners became expert at determining which wall to shoot to cause the roof to collapse and crush the insurgents fortified inside interior rooms."</p>

<p>The NE round is supposed to be capable of going through a brick wall, but in practice gunners had to fire through a window or make a hole with an anti-tank rocket. Again, from the <em>Marine Corps Gazette</em>:</p>

<blockquote><p><em>"Due to the lack of penetrating power of the NE round, we found that our assaultmen had to first fire a dual-purpose rocket in order to create a hole in the wall or building. This blast was immediately followed by an NE round that would incinerate the target or literally level the structure."</em></p></blockquote>

<p>
The rational for this approach was straightforward:</p>

<blockquote><p><em>"Marines could employ blast weapons prior to entering houses that had become pillboxes, not homes. The economic cost of house replacement is not comparable to American lives...all battalions adopted blast techniques appropriate to entering a bunker, assuming you did not know if the bunker was manned."</em></p></blockquote>

<p>The manufacturers, Talley, make bold use of its track record, with a brochure headlined <a href="http://www.talleyds.com/Product%20PDF%20flyers/smaw_ne_flyer.pdf"</a>Thermobaric Urban Destruction</a>."</p>

<p>The SMAW-NE has only been procured by the USMC, though there are reports that some were 'borrowed' by other units. However, there are also proposals on the table that thousands of obsolete <a href="http://www.fas.org/man/dod-101/sys/land/m72.htm">M-72 LAWs</a> could be <a href="http://www.dtic.mil/ndia/2004guns/thurs/rockets/johnson.pdf">retrofitted with thermobaric warheads</a>, making then into effective urban combat tools.</p>

<p>But in an era of precision bombs, where collateral damage is expected to be kept to a minimum, such massively brutal weapons have become highly controversial. These days, every civilian casualty means a few more “hearts and minds” are lost. <a href="http://www.defensetech.org/archives/000747.html">Thermobaric weapons</a> almost invariable lead to civilian deaths. The Soviet Union was heavily criticized for using thermobaric weapons in Afghanistan because they were held to constitute "disproportionate force," and similar criticisms were made when thermobarics were used in the Chechen conflict. According to Human Rights Watch, thermobaric weapons "<a href="http://www.hrw.org/press/2000/02/chech0215b.htm">kill and injure in a particularly brutal manner over a wide area</a>. In urban settings it is very difficult to limit the effect of this weapon to combatants, and the nature of FAE explosions makes it virtually impossible for civilians to take shelter from their destructive effect."</p>

<p>So it’s understandable that the Marines have made so little noise about the use of the SMAW-NE in Fallujah. But keeping quiet about controversial weapons is a lousy strategy, no matter how effective those arms are. In the short term, it may save some bad press. In the long term, it’s a recipe for a scandal. Military leaders should debate human right advocates and the like <em>first</em>, and then publicly decide "we do/do not to use X". Otherwise when the media find do find out – as they always do -- not only do you get a level of hysteria but there is also the charge of “covering up.”</p>

<p>I'm undecided about thermobarics myself, but I think they should let the legal people sort out all these issues and clear things up. Otherwise you get claims of “chemical weapons” and “violating the Geneva Protocol.” Which doesn't really help anyone. The warfighter is left in doubt, and it hands propaganda to the bad guys. Just look at what happened it last week’s <a href="http://dailykos.com/storyonly/2005/11/9/174518/797">screaming</a> over <a href="http://armchairgeneralist.typepad.com/my_weblog/2005/11/its_not_chemica.html">white phosphorous rounds</a>.</p>

<p>-- <a href="http://www.amazon.com/gp/product/0786715618/102-4141234-8123345?v=glance&n=283155&s=books&v=glance">David Hambling</a></p>

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<div class="footer"><a class="footerlink" href="http://www.defensetech.org/archives/001944.html">November 14, 2005 10:22 AM</a>&nbsp;|&nbsp;<a class="footerlink" href="http://www.defensetech.org/archives/cat_ammo_and_munitions.html">Ammo and Munitions</a>
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[Chris The Great]

Very interesting read and informative links!
Thanks alot.

From what I have gathered, this weapon is basically a small FAE that uses aluminum as the principle fuel to generate the massive blast effects shown. Is this correct?

[me234]

You guys thinking that 25/75 PVN/Al mixture that was mentioned some time back here on the Forum?
If I recall correctly, it required a hell of a booster as it wasn't very enthusiastic about detonating due to the very low amount of HE in the mix. And on a small scale, the large booster may prove a waste of space.
Maybe the use a 60/40 Al/PETN (IIRC) mix that someone either here or on the APC mentioned. The guy said it made a really nice flash when it went off.

Any word on the composition they're using JC? I read some of those links and I didn't find anything.

[Chris The Great]

One could use the booster charge as the explosive bursting charge for the warhead, to disperse the Al powder for the FAE explosion. The HE in the Al composition would ensure ignition of the Al while the "booster" would give it the necessary efficient dispersion.

Sound like a good idea? It would most likely work even if the HE in the Al fuel didn't detonate.

[MrSamosa]

Wouldn't using an HE mixture defeat the purpose of a thermobaric round?? The point of a thermobaric bomb (or "Vacuum bombs" as they came to be known in Chechnya) is to use atmospheric oxygen as the oxidizer for an aerosolized fuel. The metal powder, as in pyrotechnic mixture, serves to boost the explosive power. The mixture is "pyrotechnic," rather than "high explosive" (or whatever terminology you want to use, you know what I mean :) ), so that the explosion is slow and drawn out, yielding maximum damage.

The analogy I can think of that best describes this is instead of throwing a bomb into a room, turning the room into a bomb. They work better with confinement in the same way blackpowder is more impressive when confined.

The Russians love thermobaric bombs. They, too, have a thermobaric warhead for a shoulder-launched system--the "bumblebee" round for the RPG-7.

The discussion of fuel choice/detonation might be recycling other threads; but I still think Acetylene has high potential in these types of weaponry. It is easily dispersed, decently cheap, and has a wide range of concentrations in air for which it can detonate (something like 2% - 80% ).

The military, of course, likes Ethylene Oxide and Propylene Oxide...neither of which are easily manufactured for home-brew warfare (Yes, I know they're easy to synthesize; but doing that for 20 projectiles with a few kg fuel each is another story). Just about any fuel, properly aerosolized, can make a decent thermobaric explosion. Flour works pretty alright, too.

[Chris The Great]

In this case the HE will barely supply any energy to the burn, rather I think it will break the Al into even finer particles and break off the oxide layer, as wellas heating them up. Therefore, when it mixes with the air, ignition is a very good possibility (not having worked with FAEs before, I am not sure exactly how hard it is to get a good ignition but this looks like it should do it very well).

If nitrocellulose is used as the 'HE' it is most likely to simply burn as the Al forms a cloud, so that it immediatly ignites when the conditions are right.

So in this case we are still using the FAE concept, just (hopefully) making the fuel/air mixture much more likely to ignite by scattering pieces of self-combusting nitrocellulose in, as well as removing the protective oxide layer on the Al powder.

[MrSamosa]

Now that I've realized how easy aerosols are to build, I'm seeing how versatile they are.

Building a rocket that a) flies straight b) disperses Fuel mixture and c) ignites it at the proper time is pretty complicated.

What if a pressurized grenade is used instead? (By grenade, I mean something along the lines of a 37mm round). The concept seems simple enough--on firing, the aerosol can is forced into an "open" position, leaving a stream of fuel behind it as it flies. Once it reaches it lands, the fuel will be released in a much more regular pattern. There will be a simple timed-fuse on it to ignite the cloud.

The fuel could be a simple mixture of Aluminum/Zinc/other fine metal powder and some volatile liquid fuel; maybe Ether, maybe a chlorocarbon (this has the added effect of being a crude chemical weapon on burning; alternately, a substance like Hexachloroethane could be mixed with the fuel for the same effect). They would be placed in a can with a bit of dry ice thrown in and sealed.

It doesn't have to fly exactly straight; it would be more of a parabola. This shouldn't hurt its destructive abilities much, seeing as the military FAE rounds don't do much penetration either and have to be fired through windows. If anything, it might increase its utility; power it up, and you have an FAE mortar, which would be extremely effective since FAE's feed off of one another.

The US military's FAE bombs do not use explosive dispersal; the use aerosol dispersal means.

[simply RED]

This is PBX kind - a mix of HMX, plastificator, polymer and Al powder.
The charge is detonated from the front end.

Nothing new...

[Jacks Complete]

No word on composition. I think they are keeping it secret. I assume the issue with the wall penetration is that the shell gets mangled, and so won't disperse properly.

Once a few of these fall into the hands of the anti-US forces it will be interesting to see what counters get used by the buildings, etc. in the combat zone, on both sides. Considering that the US loses a few troops a day, the impact of one of these being turned around and killing 25 and levelling the structure totally is an interesting one to consider.

Hand-held-sized, easy to conceal, phallus shaped... I can see these being smuggled all over the place. A suicide hand grenade that levels buildings...

MrS, no need to go for the complexity of a rocket. The US have left them as simple lumps that follow a ballistic curve. Using them as mortars might be hard, though, as they would either penetrate the ground or damage themselves. Getting it just right would be tricky. You would also need to factor for wind, dispersion rates, other ignition sources, etc. when firing a salvo.

One way to mitigate these rounds might be to leave a few lit candles about the room, leading to pre-ignition and partial failure of the round.

[simply RED]

I read report on this thermo composition and it is exactly PBX with the upper formula.
The report states that it is 20-30 % stronger than Schmel. This is well understandable as isopropyl nitrate is no match to HMX...

This round can not penetrate walls. It should enter through the window.
It is very hard to hit the window of a building with this - it flies like a thrown stone, almost on balystic trajectory.

Of course the round will be devastating on cars, wooden structures etc...

[meyer25]

A possible active charge in thermobaric/FAE rounds or bombs are highly volatile, pyrophoric (self-igniting upon contact with air or moisture) triethylalane/triethylaluminium, Et3Al (TEA), diethylzinc, Et2Zn, mixtures thereof, or mixtures with oxirane/ethylene oxide or just simple hydrocarbon fuel such as gasoline in appropriate ratios; the major advantages of this type of charges (organometallic) are the above mentioned pyrophoricity, thus no need for secondary burst and extremely high burning temperatures. I think its rather useful for smaller FAE charges.

[nbk2000]

The very thing that makes TEA so useful is the very thing that prevents its use...spontaneous ignition in air.

To carry enough TEA in a man-portable missile, it must have very thin walls. These very thin walls are easily punctured by bullets and fragments which occur with annoying frequency in combat.

Upon puncture, the TEA proceeds to leak out and ignite, turning the man carrying the missile, and anyone nearby, into screaming torches. :)

Hence, not very popular.

[meyer25]

To carry enough TEA in a man-portable missile, it must have very thin walls. These very thin walls are easily punctured by bullets and fragments which occur with annoying frequency in combat.

Upon puncture, the TEA proceeds to leak out and ignite, turning the man carrying the missile, and anyone nearby, into screaming torches. :)

Hence, not very popular.

Use of FAE in small loads does not necesarily implicate thin walls. Its a question of primary burst charge. Given the vigourosity of the reaction with air, and the amout of oxygen, consumed by it (about 240L O2/100g TEA) , there is no need for that thin walls.
I think the risk of carrying it in the combat is comparable with any weaponized CW agent, or WP grenades/shells. Once it gets punctured or the wall leaks upon a bullet impact, it will burn rather than im-/explode. Surely, a burning FAE charge is unpredictable risk and it might go boom, but not immediately in my opinion, if so.

[megalomania]

It all depends on your relative frame of reference, meyer25. If the walls are thick enough to withstand a bullet impact, or two, or an explosion, then you must sacrifice either fuel load or portability. Even then there is probably no guarantee your weapon will not blow up on you. Therefore you might as well not even bother with reinforcing the weapon so that you at least have additional fuel capacity without sacrificing portability.

This type of weapon does not inspire confidence in the soldier who must carry it. Unless you have a corps of dedicated suicide troops, which western armies do not have, no soldier will touch such a thing. What good is a weapon that is potentially more dangerous to the user than to his targets?

[nbk2000]

Such a problem has already been encountered in the form of Flamethrowers.

Troops love 'em because they do the job of getting the enemy out of otherwise impenetrable fortifications.

But the guy who has to carry them (and those around him) hate 'em because every enemy trooper is shooting at HIM because they know what the flamethrower will do to them if he gets within range to use it.

As for the use of TEA in man-portable weapons, refer to the below link:

http://www.google.com/search?hl=en&lr=&safe=off&q=M202A1&btnG=Search

http://www.angelfire.com/wi/jaysdomain/M202a1.jpg

Also


D-26. ROCKET, 66MM INCENDIARY, M74, TPA (1340-H110)
a. Evidence of greyish/white residue on round/ warhead could in fact be an oxidation product from the triethyl aluminum, but could also be residue from excessive epoxy sealant used to secure fill plug.

b. If greyish/white residue is found on warhead, perform the following test:

...

If residue is oxidation product from triethyl aluminum, it should dissolve away. Follow procedures of reference directing clip be submerged in oil, and report as a critical defect.


This is for microscopic pinhole leaks, requiring the whole thing be submerged in oil and reported as a hazard. These rounds are under pressure from evolved gases created by acidic reaction with the containing shell.

So if it gets punctured in the least little bit by a bullet or fragment, you don't have a 'leak', you have a 3000&deg;F torch setting fire to anyone and anything within range.

With pyrophoric agents like this, any leak is considered a catastrophic failure.

[sparkchaser]

There are also other things in the U.S. arsenal that are potentially hazardous to the user and others nearby. One example would be the catalytic gas producing unit that is used for spinning up the gyros on a stinger missile. Using it in the proper manner makes it heat up to over 400 degrees F.

If you need to change it out while using the missile (it only last for three minutes before you need to change it out for a fresh one, or else the gyro slows down and it loses target acquisition), you need some very stout gloves or you will lose all the skin on your hand.

I believe the canister uses hydrogen peroxide, but I can't remember. A puncture would be bad. Can't forget about Li/So2 batteries either. They have a bad habbit of venting So2 and causing problems.

As for the ethics of thermobaric weapons, I would personnally level a building and deal with the mental aspects of a possible civilian casualty or two rather than run into a building and encounter the expected casualty rate of about 70% for squad or platoon sized element in an urban environment.

[meyer25]

Well then, neither are possible oxirane/ethylene oxide charges secure enough to call confidence of fighting troops, given the toxicity of oxirane which is as high and treacherous as that of phosgene is, plus additional fire/explosion hazard.

"Overfueled" slurries of Mg/Al powders with nitroesters are likely to decompose explosively upon contact with water and subsequent hydrolysis...every design/active load carries its risks and I really don't think organometallics are inacceptably risky compared to other possibilities.

[Karstjager]

Russian RPO -
http://russianarms.info/enghtm/books/weapons/49/index1.htm
and
http://russianarms.info/rushtm/books/granati/books_copy(13).htm

[Diabolique]

This thread explains many things I have been reading over the past decade. The explosives labs have been working with formulations with very large portions (as high as 80% by weight) of aluminum, well beyond what could be consumed by the oxygen in the explosives. The explosive in the formulation must be only to disperse and raise the temperature of the aluminum to the ignition point. Take a look at the MOX-series and RX-03-series explosives.

I obtained the above info mostly from LA-13014-H - "The Insensitive High Explosive Triaminotrinitrobenzene (TATB)" out of Los Alamos. It is on the ftp site.

Another report I read was about testing various metals (magnesium, aluminum, titanium and zirconium) for use as an incendiary/shrapnel liner in warheads and bombs. Only aluminum and zirconium ignited (magnesium didn't come close to ignition!). Zirconium 'moss' was the only one to fully ignite, and start fires in 2x4 lumber. After that paper, there is nothing more that I have found on using zirconium. Zirconium was suggested back in the 70's as a cladding for depleted uranium anti-armor penetrators as it ignites as it passes through the steel of the armor, causing a flash fire inside the tank.

The military in the US used TEA in 2.5 inch rockets shipped in 4-pack launchers, the predecessor of the SMAW, I suspect from the description. They used a small burster charge to burst the warhead of the rocket, dispersing the TEA in the air. Each rocket had about 250 ml of TEA, and burned so hot that it's fireball could inflict third degree burns at 50 meters. It was classified as an incendiary weapon, which are no longer in favor.

As for leaks, the militaries of the world have been using phosphorus since WW1, so they know how to prevent them.

[nbk2000]

Phosphorous is a waxy solid. If the container gets punctured by a bullet, it smokes and burns, but you have time to bail out or throw it away.

A bullet punctures a FLASH round full of TPA...*CRISPY* is what you'll be in the blink of an eye. :p

[Chris The Great]

Perhaps gelling it would be a solution that our friends at the military may have worked out, to prevent the above situation. Seems plausible enough IMO.

[nbk2000]

The solution they found to the hazards of TEA was to not use it at all. :D

TEA (dissolved in n-Hexane) burns extremely fast and hot. So fast that it can flash-burn without direct contact.

But that also prevents ignition and sustainable burning, as targets get a carbonized char layer that acts as an insulator.

They thickened it up with PIB to slow down the burn rate and allow it to stick to targets long enough to ignite targets it came in contact with, but then you lose the nuke-like flash burn effect because of the slower combustion rate.

[Chris The Great]

Idea: one could use TEA as an igniter in the thermobaric mixture. The mixture would be primarily Al powder. TEA would be mixed in, about 5%, so that the mixture is solid and won't run. If ignited accidently, it will burn vigorously, but because the main fuel is solid Al it won't go very fast and flash burn. However, when exploded properly, the mixture is dispersed into the air and the TEA ignites the Al could for a thermobaric blast effect (and probably a good deal of flash burning from the heat release).

Obviously, other pyrophoric fuels can be used instead of TEA, however I can't think of any good cheap ones that could be done. TEA on the other hand is not too difficult to make with ethyl chloride, aluminum and a small amount of sodium (eBay).

In any case it is best not to have one's explosive weaponry shot at since there is always a risk of it exploding and killing the operator.