Monday, May 07, 2007

Jack Bauer Tally: Hours 18, 19 and 20

I haven't written much because to be honest, there hasn't been much to write about. This has been the dullest few hours of 24 since Kim met the mountain lion.

Jack swiped the 'FB sub-circuit board' from Mike Doyle at gunpoint, stole his car and headed off to meet Chang with a brick of C4 and a deathwish. After ditching the tracker under some powerlines (thank you, electromagnetic interference), he got to the meet point early and rigged the building to explode. Mike followed him and got there just before the Chinese, who were bringing the soon-to-be-revealed-as-catatonic Audrey Raines. Mike got a team in place, but not quite, and as he found out Chang was about to kill Audrey he capped a guard and everything fell apart.

One of Chang's guards immediately shot Jack at close range with what looked like a Heckler & Koch G36. Jack managed to recover enough to shoot the guard and one other, the only two kills in the last three hours. Chang and his remaining homies got away with the FB sub-circuit board in a plethora of black Hummer H1s, and was lost to tracking. Jack was arrested (again) and taken back to CTU (again) along with Audrey, who as it turns out can't generate much in the way of a complete sentence.

Chang had the gizmo, which includes a part of the decryption algorithm for Russian military equipment, analyzed by one of the apparently countless goateed hackers with intimate knowledge of foreign military systems in the Los Angeles area. The circuit board doesn't work, but nobody but Chang knows that. The Russians know the Chinese have the board because Lisa Miller, the skanky blond the VP has been having an affair with, has been two-timing the VP with a KGB mole.

Audrey was evaluated by a psychiatrist from 'District' (where is that, actually?), who declared her to be a catatonic due to torture and pharmaceuticals and immediately prescribed a regimen to improve her cognitive functions, consisting of torture and pharamceuticals. Mike Doyle let himself be overpowered by Jack, who opened and open-hand can on the psychiatrist and squirreled Audrey away to some dark corner of the CTU complex, and got her to say one word, which led CTU to a chemical factory where Chang is apparently holed up. Big Daddy Raines, the ex-SecDef, told Jack in no uncertain terms that he is not to see Audrey ever again, and stated (correctly, given his history), that Jack is cursed and everyone he loves dies or gets kicked off the series. I don't know if he included Edgar Stiles in this list, but the effect is the same.

Yawn. This is getting to be as bad as Spiderman 3. There's no crying in Spiderman!

Technical Note: Body Armor

The fact that Jack was wearing body armor should not have protected him from an assault rifle at 15 feet. Not all body armor is created equal.

All body armor is for the most part created the same way: fibers of some exceptionally strong material (Kevlar, Twaron, Spectra -- all plastics) are woven into layers and multiple thicknesses of these super-strong fibers are sewn together to make "soft" body armor. The reason soft body armor works is that rather than the kinetic energy of an incoming bullet staying on a tiny point where the bullet impacts, the individual weaved fibers spread the force out over a larger area, meaning that the energy is dissipated into the vest.

The National Institute of Justice has developed a testing system whereby soft body armor is tested to determine its ability to resist penetration and deformation against a variety of standard bullets. Penetration isn't the only thing, deformation is important as well. If a bullet doesn't penetrate a vest but it does allow your chest to be compressed so far it breaks ribs and does equivalent damage, it's not adequate. The NIJ "Levels" are as follows:

Level I will stop low-velocity .38 Special, up to 850fps or a .22 LR at up to 1050 fps. Virtually no vests on the street today are Level I.

Level IIA is equivalent to 16 layers of Kevlar and will stop a 9mm FMJ bullet at up to 1090 fps, or a .357 hollowpoint at up to 1,250 fps. This is good for most street situations.

Level II is equivalent to 22 layers of Kevlar and will stop a 9mm FMJ at up to 1175 fps or a .357 Magnum hollowpoint at up to 1,390 fps. You will likely get less blunt trauma from the force of a bullet compared to level IIA.

Level IIIA is equivalent to 30+ layers of Kevlar and will stop a 9mm FMJ at up to 1400 fps or a .44 Magnum at up to 1400 fps. The 9mm speed is typical for bullets coming out of longer barrels, i.e., submachineguns.

Note how the increase in velocity changes the number of Kevlar layers needed. A 10% increase in velocity separates Level II and Level IIA. This is because velocity is the major determining factor in force, from the equation f=mv^2, where the velocity is squared. To protect against a 10% increase in velocity you have to up the Kevlar thickness by about 35%. To protect against a 40% increase in velocity you need almost 100% more Kevlar between you and the bullet.

Note also the absence of any mentioned rifle bullets in this crowd. Rifles have incredible velocity compared to pistols, a 9mm at 1400fps is considered a "hot" bullet. A .223 (the caliber of the M16, and the G36 the Chinese dude used to shoot at Jack) is considered to be loafing at under 2500fps. Standard .308 rounds do about 2,700 fps out of a rifle barrel. It would take a mattress of Kevlar to have a prayer of stopping a rifle bullet, and most people can't pull off wearing a mattress inconspicuously.

To get above Level IIIA, you need something much sturdier than even Kevlar. At present, the two choices are metal or ceramic composites. The metal can be steel or titanium, the composite is some kind of borosilicate thing that sounds expensive because it is expensive. This is called a "trauma plate", and is worn outside the body armor in a pocket on the front and back of the fabric that holds the armor panels together, called a "carrier". The job of the trauma plate is to absorb the energy of the bullet and/or fragment it, so that the force that comes out of the back of the trauma plate and hits the rest of the vest can be dissipated by the vest itself.

Level III armor will stop at least six rounds .308 Winchester round at 2,750 fps. This is equivalent to 6mm of steel, 13mm of ceramic, or 25mm of extra polyethylene (Spectra).

Level IV armor will stop at least one round of .30-06 military M2 armor piercing ammo at 2,850 fps. This is equivalent to 12mm of specially-treated steel, or 18mm of ceramic.

You could wear a plate without the armor, but the impact would be equivalent to standing on home plate while Barry Bonds swings at a hanging curveball. Or worse. The soft body armor is very important.

And strangely enough, soft body armor is non knife-proof. The force of a knife is over such a small surface area that it can split the armor and still injure you.

The only way that Jack could be wearing body armor and take short-range hits from an assault rifle and not die is if he was wearing Level III armor (hard and soft armor) and was shot in the trauma plate. Otherwise, he'd have big bloody holes front and back. The other possible solution to how he could be wearing body armor and survive is if he was wearing Dragon Skin from Pinnacle Armor.

Dragon Skin is an update of an old concept: scale mail. An outer jacket of large discs of metal were sewn into an overlapping pattern. Swords and arrows would have to pierce the individual metal discs, each of which could rely on its overlapping neighbors for structural support. Dragon Skin replaces the discs of metal with roughly 1" discs of ceramic, in a matrix of Kevlar. For its weight, it tests out better than any other armor and is less than an inch thick. Instead of being a single inflexible plate, it's many small discs that flex easily, enabling it move when the wearer moves. It's certified Level III, and it stops AK rounds as well as .223 rounds. What's more, it will take a number of hits without quitting. The ceramic trauma plate typically shatters in the process of absorbing the energy from the bullet, meaning within a few hits your Level IV vest has gone to a Level IIIA vest with a pocket of gravel on the front. Individual Dragon Skin armor discs may shatter, but the rest of the vest is intact, and it takes just plain bad luck to take enough hits on one spot to let one get through.

Dragon Skin has seen use by Special Forces in the Afghanistan and Irsq campagins, it's popular because it's light and apparently reliable. Pinnacle has been trying to get their flexible Level III/IV system into the mainstream with the DoD, but they've been hitting some roadblocks in getting the Army to replace their Interceptor system with the Pinnacle SOV-3000. I would guess the main roadblock would be the $3-5000 it costs to outfit every ground-pounder with a new Pinnacle SOV-3000.

In summary, soft body armor isn't bullet-proof, it's bullet-resistant. To survive .223 shots at close range, Jack Bauer had to be wearing NIJ Level III or better armor, either with a trauma plate or Dragon Skin flexible armor with integrated armor scales.

Jack got two kills from the ground. Yawn.

The Score so far:

Biting A Carotid9.0 -1 for lack of Universal Protocol
Shooting Curtis-8-10 own goal, +2 neck shot over a hostage
Shooting guard while handcuffed7.0+2 for while handcuffed
Handgun6.0+1 for saving hostages (Milo & Graeme's wife)
Handgun7.0+2 for disarm
Handgun6.0+1 for suppressor, because suppressors are cool
Handgun6.0+1 for suppressor
Handgun6.0+1 for through car window
Handgun10.0+5 for called headshot
Neck Snap7.0Always cool.
Handgun5.0Fayed henchman
Handgun5.0Fayed henchman
Handgun5.0Fayed henchman
Handgun5.0Fayed henchman
Handgun5.0Fayed henchman
Length of Chain8.0Strangled Fayed
Handgun5.0Chinese henchman
Handgun5.0Chinese henchman

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