OMG, It's The Attack Of The Morons
If the recent car burnings in England are technically anything at all as they are being reported, they were executed by morons. According to the news reports, the first two incidents being reported, the idiots loaded a bunch of gasoline and propane containers into cars and set up a cell phone to trigger something that would set them aflame. When those failed to assplode, it appears a couple of fools probably connected to the first two failures (if not exactly the same idiots) pile into another vehicle loaded with some gas cans and ran it into the airport lobby while at the same time firing up the gasoline soaked interior of the vehicle probably with a Bic.
Since at least the first two car duds also included a bunch of nails intended as projectiles, it appears they thought these kinds of rigs would make some kind of high velocity explosion. It ain't going to happen.
Even if they got the mixture right, only few ounces of the fuel they chose would have contributed to an explosion. The rest of the fuel would have served more to dampen the forces of a very puny pop and maybe would have caused a little secondary boom when the propane bottles got around to blowing because of overpressure from overheating. Probably the propane tanks would simply have melted their safety plugs and burned. Or, burnt as they do in England.
There are very good reasons those things didn't do much more than make a bunch of idiot-news-heads get breathless. Anyone who made at least a "C" in physics in any grade higher than about 6 would understand how stupid those devices were. Just in case there is a folk or two that might read this and wish to make a boom with gas, I'm not going into details here. I don't want you to burn up no more good cars. You could hurt yourself.
What I am going to do is say that the new folks covering this stuff as well as some of the so called officials are being laughed at for their stupidity in thinking this was some kind of credible attack. All civil humanity would have been far better served had these incidents been used to illustrate that these so called terrorists are indeed as laughably ignorant as they are barbaric.

