Kinder, Gentler Thermobarics
Thermobarics are known as some of the most ferocious weapons an army can have. But not all of 'em are about death and destruction.
The U.S. Department of Justice, for example, is funding a thermobaric stun grenade. Known as the "Fuel Air Diversionary Device," it's more powerful -- but less dangerous -- than existing flash-bang devices. The munition doesn't produce any hazardous shrapnel, and the 'near field' blast isn't as intense as condensed explosive.
Developed by Sandia National Laboratories, the grenade expels a cloud of fine particles through vents with the aid of a gas generator. This fuel-air cloud then deflagrates -- rather than detonates. The explosion is at subsonic speed, so the overpressure is much less than the lethal thermobaric devices discussed previously. However, the project requirements specify "the overpressure energetic shock wave will be sufficient to knock down a man of average size and weight," so don’t think that it’s underpowered.
when the round bursts, flake aluminum is ejected and ignited to create a brilliant flash that is comparable to looking directly into the sun for 60 milliseconds but causes no permanent damage to a person’s vision. In addition, the flake aluminum poses no appreciable burning hazard. It cools to the ambient temperature within a fraction of a second. The acoustics, he said, reach a level of 170 decibels, but again, cause no permanent damage.
Maybe. 130 Dbs of sound is physically painful - 170 Db is even worse.
At least the thing isn't very likely to go off accidentally. The grenade's filler is not explosive per se, and can’t explode while it’s contained. What's more, sympathetic detonation is not a problem, and it can’t be set off by sparks, heat or impact. The well-known ability of thermobaric blast to 'flow' through apertures and around corners will enhance its effectiveness inside buildings.
While the grenade itself is an interesting step forward, we may see a lot more devices based on this technology. The makers say that by altering the variables "metallic fuels, organic fuels, blends, particle size and morphology, gas generator output, etc." – a wide variety of different outputs can be achieved. The device could be optimised for flash, or the blast can be of tailored strength and duration to maximise its effectiveness, depending on whether you want to dazzle, deafen or just knock them off their feet.
It is also significant that this is highly scalable. At a presentation the European less-lethal weapon conference last year, Mark C. Grubelich of Sandia included a comment about "devices demonstrated with 10’s of milligrams to 10’s of kilograms of fuel."
This suggests a number of novel devices. At the lower end you could have an explosive baton round that would produce a non-lethal blast on contact – this would get over the usual problem with kinetic rounds that they are either dangerous at point blank range or ineffective further out.
Twenty grams of flake aluminium produced a fireball two metres in diameter brighter than the sun, engulfing the target in a blinding, deafening but harmless explosion.
A hand-thrown device containing more fuel could fill a room or corridor, or perhaps (given the increased effectivenss of thermobarics indoors where there are walls and ceilings to reflect and amplify its power) neutralize a small building.
Or you could have a larger wide-area flash-bang bomb which could subdue a crowd, or at least give them some non-lethal "shock & awe." The stun effect should last long enough to move in and grab the hardcore violent members of the crowd while they are too stunned to resist.
A big part of the secret to tailored thermobarics is nanotechnology to produce very precisely graded particles, a topic explored in my book Weapons Grade. It can mean the difference between damaging buildings, demolishing them, simply killing the occupants -- or perhaps just simply stunning them.
-- David Hambling
Remember the decibel scale is a log scale as well.
Posted by: Charles at August 6, 2006 1:28 PM