by CKR
Time Magazine, in its 16 July issue, reported on the exploding Jeep Cherokee at Glasgow Airport and other vehicles loaded with gasoline and propane tanks.
The London car bombs were fuel-air explosive bombs—designed to produce a huge fireball by igniting aerated liquid gasoline. Had they worked, scores of people could have been severely burned.The discussion of fuel-air explosives from the Federation of American Scientists gives some idea of the difficulty of making this happen, but it’s a fairly technical explanation, so probably the Time reporters didn’t bother with it.
The bottom line is that it’s difficult to get a proper mixture of fuel and air to produce an explosion. Serious fuel-air mechanisms have dispersal mechanisms and close timing on the detonators. The British car bombs had none of this. It’s not even clear to me that a fuel-air explosive was what was intended, but perhaps the Time reporters are privy to terrorist secrets or are better at mind-reading than I am.
It looks more to me like the intention was to ignite a fire with the gasoline that would explode the propane tanks in a boiling liquid expanding vapor explosion (BLEVE). If the propane could be heated to a pressure that would breach the tank, all the propane would effectively vaporize instantly, releasing a great deal of energy and, for good measure, ignite or explode.
Gasoline itself is a pretty good explosive when properly mixed with air. My father once decided to use gasoline as a thermobaric weapon against gophers, much as such weapons were proposed for killing al-Qaeda members in Afghan caves. My father, however, thought of this twenty or so years ago.
The procedure was to pour a few ounces of gasoline into the gopher hole, properly excavated, wait thirty seconds or so for it to evaporate into the proper mixture with air, and ignite it with a match. Ignition is best done from a distance, some tens of yards away in my estimation. My father stood within easy match-flipping distance. The bang disturbed the neighbors and frightened my father sufficiently that he never used that method against gophers again.
Looks like the MD wannabe bombers didn’t even do that well.