Re: London "Bombs"

In article <uIKdnVxbWKav4RfbnZ2dnUVZ_gudnZ2d@xxxxxxxxxxxxxx>,
Islander <nospam@xxxxxxxxxxx> wrote:

Islander wrote:
Jean Smith wrote:
I've glad to see the ineptitude continues. Hopefully, their
fingerprints are all over the cars the cans and arrests will be made
before the perps figure out what they need to have an explosion.
Searching Google Groups on this subject brings up lots of speculation,
such as, the smoke in the first car being fuel vapor (which could
explain the intoxication), and lots of skepticism and derision. If
they had a good fire going in spilled gas, would the propane spilled
from the pressure relief valves put the fire out by driving out
whatever oxygen had not already been consumed?

My first reaction to this when I heard the news was disbelief at the
hysteria in the news media. Sure, it might produce one heck of a fire
ball, but would the nails, etc., produce a shrapnel-like effect? I
doubt it.

As far as explosive capability, gasoline ranks up there pretty high, but
it needs to be vaporized and mixed with oxygen. Otherwise, it just
burns. Propane has less energy content. If the fire provided by the
gasoline caused the tanks to rupture, it would produce a fireball, but
not much more. More likely, the pressure relief valves would vent,
producing some flame, but not an explosion unless the temperature got
high enough to cause the tanks to rupture. In any case, it would not be
expected to product the same explosive effect of more conventional
explosives.

I wouldn't want to bet on the heavier propane extinguishing a fire,
however!



There was a segment on CNN this morning where they duplicated the
propane/gasoline car bomb in an isolated area. They taped hex nuts to
the propane tanks to simulate the nails used in the British devices
(they explained that they didn't want to spread nails around the area
for fear of causing flat tires).

I'll have to say that the explosion was spectacular! Quite a large
fireball which also consumed a plywood structure erected next to the
Jeep Cherokee used in the demonstration. While they emphasized the
damage that might have resulted from the explosion, I didn't see much
evidence. The rear lift gate was blown off and one of the doors was
blown open. Otherwise, there were no holes evident in the *** metal
from projectiles and the reporter picked up one of the hex nuts a few
yards away from the vehicle (while describing how someone could have
been injured -- a bit of an exaggeration, IMV). One of the propane
cylinders ruptured and was found about 150 feet away, not surprising
since a compressed gas container might well tend to be propelled by the
gas once the container is compromised.

Make no mistake, this kind of car bomb is dangerous, primarily because
of the fire ball. However, it would be wrong to equate this to the much
more dangerous devices built of nitrate based, dynamite based, or other
high explosive material.

I would conclude that this may be an indication that more dangerous
explosives are getting more difficult for these groups to obtain. If
so, that would be good news.

Recalling the Glasgow episode, two out of three doctors will exit the
vehicle and walk around after the device goes off. As a chariot to heaven,
these things aren't dependable. I wish they'd left it that way.

This demonstration is a quirky thing to do. Why encourage the nuts to go
back to work until they get it right? I guess this media arm of the VRWC
really felt that we weren't scared enough. Only 4% of volunteers on the
website admit to changing their travel plans in the light of this wave of
incidents.

--
Mother Tongue Bothers http://www.mtannoyances.com/?p=371 http://www.whynot.net
Op-Ed Columnist: A Vice President Without Borders, Bordering on Lunacy
http://environment.newscientist.com/channel/earth/climate-change/dn11651
.