Any time the media reports on anything slightly technical they merely prove that they are journalists not engineers.  The current stories about EFPs (explosively formed projectiles*) highlight their lack of sophistication at relating technical material.

The first thing to notice is how they say it: “EFP or (very slowly) e-x-p-l-o-s-i-v-e-l-y f-o-r-m-e-d p-e-n-e-t-r-a-t-o-r,” as if it is some foreign language.  Then comes the ham handed explanation of how it works and why it is used.  NBC even threw together a goofy graphic that showed the liner (read below) installed backwards.

An EFP is very simple to describe, but difficult to make.  It is essentially a cylindrical canister filled with explosive.  On one end of the canister is a thin metal sheet (typically copper), usually formed into a shallow dome, with the dome “pointing” into the canister.  When the explosive is detonated the sheet, called a liner, inverts as it is propelled away from the bomb by the rapidly expanding pressure.  As the liner is propelled it collapses into a slug that moves at speeds over one kilometer per second.  If the EFP is properly designed (big if) the slug can travel many meters and strike a target at high speeds, penetrating very robust armor.  Think back to high school physics.  Kinetic energy equals one half times the mass of the object times the velocity squared.  What that means is that a relatively small, light quantity of metal traveling at very high speeds contains lots of kinetic energy.

In addition to being difficult to design, EFPs also require much more precise usage than does a regular bomb.  A bomb throws its energy out in all directions, which is not a terribly efficient way to attack a specific target at a known location; too much wasted energy.  It is a great way to attack a widely dispersed target set, though.  An EFP allows you to direct a significant amount of the weapon’s energy towards your target in the form of the kinetic projectile.  Where the traditional bomb allows for crude fuzing mechanisms, the EFP requires very exact timing.  If your projectile misses its target, then there will likely be no, or very little, damage compared to what could have been inflicted with a larger, traditional bomb.

If the media can’t do a good job explaining something as simple as a can of explosive with a metal cap how much do you think they’re screwing up the presentation of complicated things like “global warming?”

*You may hear the term explosively formed penetrators being used, but I’ve always heard and used projectile.

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This entry was posted by Brian on Monday, February 12th, 2007 at 11:07 pm and is filed under Iraq, Media. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site. Please note the copyright policy.