Thermite Fuel Air Explosive Devices aka Hellhounds

[akinrog]

Dear Friends,

Since I shall not provide new information, I'm strarting this thread in Water Cooler section.

I'm currently on the trails of a Thermite Fuel Air Explosive Device alias Hellhound, which is claimed to be used during Vietnam war.

Unfortunately, I cannot find much information about this device except a few words in SM and some crude descriptions here in RS under the thread entitled "KGB files"

The device, apart from being very cheap method of wreaking havoc (with its claimed effective killing radius of 100 yards - approximately 100 meters), is quite simplistic.

I suspect this is the device used by Chechnian terrorists ten years (?) ago to demolish some Russian buildings in Moscow together with its inhabitants. Then I could not figure out what it was since news coverage of that time only said it was a type of pipe bomb which in essence puzzled me a lot since I wasn't aware of any pipe bomb which can bring down entire buildings.

In addition, claimed to be used during Vietnam war, I cannot find any reference to this device on the net.

Anybody may happen to have some info on this (not the improvised one but the real one together with some design aspects)? Regards

[bipolar]

This is the what I have known as a standard Fuel Air Explosive weapon. It is in this special forces demolition instructors manual I used to have, and other books. Basicly a small ammount of High Explosive material with a layer of thermite on top. On top of that is a proportionaly bigger box or container of your fuel. This could either be flour, sawdust, or other powdered fuel, or liquid fuel too. It was reffered to as HELLHOFTE fuel air explosive or something like that in these manuals.

From what I understand the concept is the high explosive detonates, at the same time ingiting the thermite and dipersing it with the fuel.

While the fuel may start to burn, everything happens so fast and the burning thermite is dispersed along with it and ignites whenever the stoichiometric ratio is reached with the fuel and air and it explodes.

This same basic concept can be modified to put the design into a single device or warhead. Using a thin cylinder in the middle containing the HE, a slightly bigger one containing an outer layer or thermite. Then a much bigger cylinder around that to contain the powdered fuel.

This same technique is also used for making what was reffered to as a POL(potroleum oil liquid) charge for distroying fuel tanks from drums to larger industrial fuel tanks. This device is just an explosive charge with a layer of thermite on one side. You just attach it to a fuel drum and and detonate, and it uses the fuel in the tank as part of the explosion, turns it into an FAE. You have to scale it up accordingly to the ammount of fuel in all cases.

These are very good for clearing a whole building and the negative pressure can cause it to collapse in some circumstances if the openings are closed. It has a huge destructive effect and a destructive vaccuum pressurewave from taking all of the oxygen out of the air. If it is inside of a building many people die from just lack of oxygen. It can also go in open spaces like windows of buildings from the outside or port holes of tanks or open windows of cars.

Hope this helps.

[akinrog]

From what I understand the concept is the high explosive detonates, at the same time ingiting the thermite and dipersing it with the fuel.


Maybe you are right about above statement and as I stated before, I cannot find any good references about the device. However, those descriptions I could reach (e.g. in KGB files thread and SM) mention about reverse of what you describe.

I mean according to those descriptions, first the thermite which is enclosed in a tube (which is also enclosed in a larger and pressure resistant sealed tube, containing a liquid fuel), is ignited from one end and at the other end (of the tube) there is an explosive charge (typically flash powder). When the burning thermite reaches to the charge it sets it off which ruptures the outer tube and aeresolize the superheated fuel simultaneously throwing some thermite slug into it thereby ensuring aeresolized fuel to detonate.

To cut a long story short, it's probable that the device you described is something different from what I'm referring to or it's only a myth. Regards.

[j_dmillar]

Do you need the explosive charge? Would the pressurization of the fuel not be enough to rupture the vessel and disperse the fuel?

Oh, while we're on the subject... can anyone help me on the physics of determining (calculation, not empirically) the optiumum delay before detonation of a fuel-air explosive.

That reminds me... the problem in what you people speak of is that you don't have the delay - not mixed with air by the time it ignites, therefore slow flame front, low thermal energy to overpress/shockwave efficiency. Or am I missing something?

[bipolar]

Do you need the explosive charge? Would the pressurization of the fuel not be enough to rupture the vessel and disperse the fuel?

Well I am talking about powdered and liquid fuels, especially powdered. (such as flour or sawdust) These are not under pressure.

Using the above method you don't need a delay. solid powder fuel such as flour or sawdust or liquid fuel won't explode without a stoichiometric mixture of fuel and oxygen. It will only ignite on surface area where oxygen is available.

The explosive instantly propels the fuel into the air at the same time dispursing burning thermite or thermate along with it, which will help it explode right when it reaches a stoichiometric mixture. All of this happens in an instant because of the high explosive.

That reminds me... the problem in what you people speak of is that you don't have the delay - not mixed with air by the time it ignites, therefore slow flame front, low thermal energy to overpress/shockwave efficiency. Or am I missing something?

So the fuel actually does ignite but this all takes place so fast because of the HE that the majority of it doesn't burn until enough air is mixed with it to explode.

There are other methods of FAE's but I like this method because it's simple and effective so you don't have to calculate the optimum delay. The concept of the device takes care of that naturally.

[nbk2000]

There's mention of a thermobaric 40mm ammo called "Hellhound" in this article:

http://www.defensereview.com/article749.html

Not the same thing, of course, but similar concept.

Judging by the picture, the improved lethal range for the non-thermobaric type is because the fragmentation case is actually formed into many self-forging fragments the explosion, rather then using typical pre-made fragments like ballbearings.

There's a recent french patent that details the design, and it seems too similar to be coincidence, I think.