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Toyota hydrogen fuel cell (courtesy green.autoblog.com)

“Many gearheads will remember that the 1970s-era Dodge Dart‘s claim to fame was that its motor was so durable (though not necessarily powerful) that one could shoot bullets into the engine block,” green.autoblog.com recalls. “Decades later, Toyota has taken a page out of that testing process. With some industry members and analysts questioning both the viability and durability of hydrogen fuel-cell electric vehicles, Toyota executive Bob Carter, speaking at the Automotive News World Congress this week, says the Japanese automaker went all Clint Eastwood on the fuel tanks of a fuel-cell prototype. Carter says that bullets from a small-caliber gun bounced off the carbon-fiber tanks, and that .50-caliber bullets barely made dents.” Seriously? [h/t Pascal]

[UPDATE: Autoblog got it wrong in their writeup (quoted above). The .50 caliber bullet didn’t just barely make a dent. According to the original press release, it penetrated, but still did not result in an explosion. “It took a 50-caliber armor-piercing bullet to penetrate the shell. And, even then, it just left a hole and the hydrogen simply leaked out.”]

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76 COMMENTS

  3. Anything is possible when those .50 cal loads are hand loaded to ultra light with fragmenting bullets. Besides where did they find firearms in Japan, or did they test them in the U.S.?

    • Guns aren’t completely illegal in Japan. I believe you can have firearms, at very high cost, with very high fees, if said firearm is for hunting. A corp could likely get one for “engineering” as well.

      The problem with other countries isn’t that you can’t get guns. Its that only the elite can get guns, and only as a privilege, not a right.

      • You can actually get guns for pretty cheap in Japan. The problem with getting a gun in Japan is that the licensing is so difficult that almost no one does it. There is a gun shop in Yokohama that sells almost exclusively to American servicemen because they operate under different rules. I got a Remington 1100 and an Browning Auto 5 for 242 dollars then got to learn the joys of dealing with the ATF when I shipped them home.

      • Guns as we know them are almost completely illegal. Their law starts with “No-one shall possess a fire-arm or fire-arms or a sword or swords.”

        Any ownership is an exception to that law. Even swords are registered and subject to strict licensing. Small caliber rifles were allowed until 1972. Now only air rifles and shotguns.

    • Really? Somehow I don’t think Toyota would have any trouble gaining access to ANYTHING that is otherwise restricted in Japan.

  4. I’m sure the “as tested” .50 was actually a patched lead ball shot out of a downloaded flintlock.

  5. That actually shouldn’t be all that surprising. Look at the tank; it clearly states 70 MPa pressure rating. That means it has to withstand a static pressure 700 times that of the outside atmosphere. To put that in perspective, you would to drop this thing most of the way down the Mariana Trench (>23,000 feet) in order to exceed just the spec pressure. Then take into account the factor of safety that is built into every engineered device. Then take into account that the vessel has to withstand impact forces in case of a car crash, where it has to be assumed that puncturing is a real possibility from either mangled car parts or road debris. Sounds to me like a .50 cal shot is a good test.

    • Only as long as the axis of impact of the round is orthogonal – NOT tangential – to the surface. Hit it straight on with a .50 cal and lets see what happens. Pressure tests assume all force is distributed evenly across the entire surface, which is valid for pressure – not impact – testing. Need to see the test results regarding significant force being applied in a single location.

    • In any crash where the integrity of a tank of even half this capability would be compromised I sort of doubt leaking and/or exploding hydrogen would be of much concern except to the clean-up crews.

      I am no chemist, but I’m pretty sure that hydrogen has to be mixed in correct proportion with oxygen in order to be explosively flammable. (Space shuttle main engines – oxy in one tank, hydrogen in the other.) Even if you penetrated this tank with a .50 tracer or a 20mm incendiary I suspect all you would get is a leak, not an explosion.

      See Mythbuster episodes where they fired tracers into tanks of gasoline and propane tanks without effect.

      • Cliff,
        The other tank on a space shuttle contains Liquid Oxygen (LOX as opposed to Lox which is dried salmon) instead of oxi.:-)

    • Um, no.

      Static loads are one thing. Dynamic loads – for instance the impact of a heavy pointy thing moving at just under Mach 3 – are a different design problem.

      Pressure vessels are generally designed to withstand relatively slow changes of pressure uniformly distributed over the surface of the vessel. Sudden sharp impacts on a single point, not usually a major design concern unless you’re designing a submarine.

    • I can’t speak for anyone else, but I treat this as little more than useless marketing fluff to assuage the misguided fears of the ignorant (like when they made a big deal about the Tundra “towing” the space shuttle orbiter.) It’s so devoid of information on what they actually did that it’s not possible to know whether it even means anything. As has been said already, “.50 caliber” could mean anything from a round ball squib load from a muzzleloader to a .50 BMG.

    • This is being done because the “pro all-electric” car camp headed by their god and savior Elon Musk have repeatedly stated and lobbied in congress that Hydrogen Fuel Cells are dangerous.

      With recent fires of the Tesla S, the rhetoric of the two camps have picked up.

      This was to show proof once and for all that that there is no danger with these fuel cells.

      Just like in the anti-gun groups, the eco terrorists have their own disinformation machine. There is a whole crowd that believes that wind, solar and electric power will somehow save the world.

      • When you go back and read the actual press release, it did state it was penetrated by a .50 cal armor piercing round. That said, I still cannot understand why auto makers don employ weighted flywheels to help generate centrifugal force to maintain engine RPM at highway speeds. Would translate into great fuel economy to help compensate for the crappy ethanol laced gasoline we now have and engines which would last forever. Okay, I just answered my own question….

        • flywheels are a huge engineering and materials science problem. they store energy with rotational inertia, which requires a lot of mass, or a high rotating speed, or both. if you make one too heavy, you waste enough energy just carting the thing around. Try to make it spin too fast, and you risk having the thing spontaneously disassemble itself in exciting ways. which is another thing- in order to protect the meatsacks in and around the vehicle, you need to have a pretty stout containment/scattershield (which is heavy.) and another bag of hurt is that if you don’t want the vehicle to have scary handling, you really need two counter-rotating flywheels.

          this doesn’t mean flywheels couldn’t work, it’s just that we haven’t reached the point where they’re worth investing in.

          • Hey, if I had already figured it out, I would be a billionaire. Just saying that all the “fly by wire” technology they have engineered into motor vehicles should allow them to overcome some of the problems with inertia inherent to the centrifugal forces. Kind of like the old Over Drives once employed in the fifties when three speed manual transmissions were used. It is not something which would be practical for city driving but could really extend fuel economy on the interstate,

            I’ve seen some pretty impressive uses for big heavy fly wheels in old saw mills where a 1hp steam engine powered a pretty massive blade. At some point, auto manufactures will no longer be able to reduce the weight of a vehicle to the point it can meet CAFE standards by weight reduction alone. I’m just thinking that sometimes old technology can be employed when coupled with computers. Look at the B2 bomber and the F117. They would be unflyable were it not for computers.

            Of course this has nothing at all to do with guns, but I digress and I understand your point and it is well taken.

        • Besides materials strength of the wheel/shielding and countering the gyroscopic effects, the third major issue with flywheels is the bearings. Strength/durability at an affordable price is a real problem.

      • “There is a whole crowd that believes that wind, solar and electric power will somehow save the world.”

        They might not save the world, but all three are (to varying degrees) worthwhile alternatives to fossil fuels. At the very least they’re worth investigating.

        There really is a limited supply of coal and oil. Honest. It’s not just a scare tactic dreamed up by wild-eyed liberal scaremongers. Its foolish to pretend otherwise.

        • I think a lot of folks are missing the point, it is not just the hydrogen… It’s the fuel cell. Who knows what other metthyl-ethyl death alternative fuel they will come up with that can be stored safely it these cells? The cells are simply a means to an end. Folks in the big cities do even care about cars because they have no need for on, they will be the first to jump on the “no fossil fuel” bandwagon forgetting it is what keeps their butts warm in the winter and cool in the summer. Folks in the country realize the need for cheap transportation but as long as it will burn in their F-150s, they will still be frugal. I am surprised they have not figured out they can distill some of that corn into grain alcohol to run their tractors, or maybe they have… Anyway, I all for coming up with new technologies which allow for us to have alternatives to OPEC.

          In the meantime, we all know it is really all about the money… That is why some folks will do everything they can to trash the opposition and laud their own ideas. I old adage of not believing everything you read and only half of what you see has never been truer than it is today… Okay, I will dismount from my soapbox and shut up about this.

        • We have exactly three types of energy available to us: solar, nuclear fission, and gravitational.

          All fossil fuels are stored solar.

          Wind is solar – the sun heats the air and we get wind as a result.

          Hydro is either solar or gravitational, depending on whether you’re tapping rivers or tides.

          Geothermal is a combo of nuclear fission (heats the eaths core) and gravitational (tidal stress flexes the mantle and crust).

          Electricity? Hah. We get that by transforming one of the other types, generally by boiling water and turning a turbine.

      • “This is being done because the “pro all-electric” car camp headed by their god and savior Elon Musk have repeatedly stated and lobbied in congress that Hydrogen Fuel Cells are dangerous. ”

        Look- I say this as a car guy, I think the Tesla Model S is a fantastic car. I just wish someone would put a muzzle on that pompous ass Musk. Sooner or later he’s going to learn that being a car manufacturer isn’t like PayPal; one more punctured battery will guarantee an expensive recall. it’s too bad his acolytes in the Silicon Valley utopia continue to fellate his ego.

    • My only reason for doubt is that they didn’t specify which .50. As meantioned, it could have been a flintlock or .50S&W for that matter. If they said .50BMG I’d buy it, but as is you have no idea what they meant. That’s either on purpose because they want it to sound stronger than it is, or they just don’t know anything about firearms. Your guess is as good as mine as to which.

  7. This could be an important consideration/criteria for police and military applications of electric vehicles.

    Additionally, a hydrogen tank that can withstand a hit from a .50 caliber bullet traveling at 3,000 fps also suggests that such a tank would likely withstand any damage that a crash could possibly cause to the tank.

    Plus, it is clever marketing. If Toyota simply stated that their tank would not be catastrophically damaged in a crash, no one would pay much attention. Rather, they stated that a large rifle would not damage their tank, and now we are paying attention. Looks like it worked.

    • Or it could result in banning any caliber weapon that could penetrate the tank. You never know which direction people might go. Social value of high-mileage, non-fossil-fuel vehicles would be high. Do it for the children. Do it for the planet. Do it for miles-per-gallon. Tongue-in-cheek pondering about unintended consequences…

      I think we need to get these things handed out to the youtube gun community for testing. THAT would be entertaining.

  8. Hydrogen fuel is right up their with ethanol as the dumbest fuel ideas ever invented. Hydrogen does not occur naturally on earth, you have to make it – first by generating electricity, then running the electricity through water. So, you have to burn fossil fuels to generate the electricity to generate the hydrogen. Or, you could build ginormous nuclear reactors (post Fukyama, I am thinking we are off that for a while). Hydrogen really functions as a battery (electricity storage) and its a poor (and dangerous) one at that.

    Plus, insofar as global warming, the global warming effect of water vapor (the result of burning hydrogen) is much worse than carbon dioxide. water vapor accounts for 98% of the greenhouse effect. true, dat.

    So if people think I will be driving around with the Hindenberg in my trunk, they are flat out nuts.

    I, for one, would get a lot of satisfaction from seeing someone blow up one of these tanks. On so many levels…

    • Dude, you’re piddling on the parade of alternative-energy unicorns and Smurfs with all that actual science.

    • I can’t tell if you are serious… You are correct, Hydrogen is not a fuel, it is a way to store energy. But getting it doesn’t have to come from the burning of fossil fuels. We have plenty of renewable energy sources from which that energy could come. Wind, solar, and hydroelectric, are three that come to mind. These that I have mentioned have been growing in recent years. Just because we might use mostly fossil fuels now to generate the electricity for hydrolysis doesn’t mean we shouldn’t still develop the technology. Also, hydrogen is quite good actually at storing energy, but yes, it can be a little dangerous. But so can lithium batteries, but we still put those in cell phones, laptops, and even cars. Also, I’m not sure why Fukushima would prohibit us from building more nuclear plants.

      Your point about water vapor being a major greenhouse gas is true, and not true. Yes, water vapor is the most abundant greenhouse gas, but the amount of water vapor you add to the atmosphere by burning hydrogen is negligible compared to the amount already there. In fact, the amount of water vapor you would add by burning hydrogen is negligible compared to the fluctuations that occur daily. Water evaporates and condenses all the time based on changes in pressure and temperature. Carbon dioxide however takes much longer to remove from the atmosphere as it won’t just fall out of the air on its own, it needs a plant to help it.

      • Fukushima should be the ultimate selling tool for returning to Thorium reactors – cheap, inherently safe, allow us to use up a bunch of other radioactive waste products. Cold war is over, light-water has served it’s (sole) purpose of generating bomb material.

        Sadly, what will happen is utterly predictable. The Chinese, Indians, Russians, Israelis and others know how well they work and how safe they are. So… Unlike the DoE they’re spending hundreds of millions to drill-down mass production techniques for LFTRs – and file all the IP they can grab along the way.

        Seaborg moved on from the light-water to Thorium by 1968. Sadly, our government is so wholly-owned by GE and others who profit from light water that we’ll be licensing the tech we invented from our competitors. Again. Still.

        • If only our government were “owned by GE” when it comes to nuclear power.

          Our government is “owned” by people who believe microwaving a burrito makes it radioactive.

        • Sorry, the “GE” thing was a bit of shorthand, I had to run. The only reason there are light-waters around instead of Thoriums is that DoE’s main business isn’t energy – unless you’re measuring by the MegaTon. DoE’s job was/is to come up with bomb materials, the rest has always been a sideshow. DoE is the definition of enslaved to the Military Industrial Complex – they’re the only real customers and the only place a nuclear scientist is gonna pick up a mid-6 figure job after leaving DoE. For awhile. Then you go back and further your former employer’s interests (just like at all gov agencies these days).

          GE, Westinghouse, Babcock & Wilcox, did, and still do a profitable business selling “mature” (read:decrepit) light-water technology to other countries. No matter which iteration from straight ABWR to ESBWR, they’re all rather high-margin. Who wants new far better tech when we make so much money with the old dangerous tech?

      • Hydroelectric: not enough rivers. Mostly all the big dams that could be built in the US have been built.
        Solar: most power demand in the US comes in the summer time when its hot, coinciding with peak sun. There is really no need to store the electricity from the sun when (if) rooftop panels become commercially viable.

        nuclear in its current form is also very expensive. I am not against it personally, but people are afraid of another Fukyama type disaster.

        As for wind, its hugely expensive, inefficient, and takes up a whole lot of land that eventually we will need for crops. Like ethanol, which grabs 40% of the corn crop. Wind technology just has not improved over the last 40 years, its merely gotten bigger. Its still a turbine on a blade.

        Hydrogen is unstable and leaks through most membranes, there are many good reasons energy is not stored in nature as hydrogen. There are many ways to store electricity chemically (like methane), hydrogen just is not it.

        As to your point a bout water vapor, do you have an impact study on changing from CO2 to water vapor on a massive scale??

        • I don’t have a study on that, do you? I admit, I’m not an expert in the field, but with fluctuations as big as we see every day in the amount of water vapor in the air, I would be very surprised if the tiny bit you add from burning hydrogen has any noticeable impact. Just because something is the most prevalent greenhouse gas does not mean that adding to it is worse than adding to another less prevalent greenhouse gas. In fact, I would say it is probably the opposite due to the higher percent change you would create on the gas that there is relatively little of.

          I do however have this article that seems to support what I’m saying:
          http://www.newscientist.com/article/dn11652-climate-myths-co2-isnt-the-most-important-greenhouse-gas.html
          I have no idea about the reputation of that website though.

          The reason Hydrogen doesn’t exist in nature is precisely the reason it makes such a good energy storage medium: it is very reactive. Also, you don’t have to store hydrogen pressurized.
          http://en.wikipedia.org/wiki/Hydrogen_storage#Metal_hydrides

          I’m not saying hydrogen is the solution to every problem ever, I’m just saying it isn’t nearly as bad as you make it out to be. I do however agree with you that people need to take into consideration where the hydrogen comes from. People blindly citing statistics about emissions from a gas powered car vs a hydrogen powered car vs an electric car, need to take into consideration emissions generated to give you those alternative fuels.

        • ” I admit, I’m not an expert in the field, but with fluctuations as big as we see every day seasonally in the amount of water vapor carbon dioxide in the air, I would be very surprised if the tiny bit you add from burning hydrogen fossil fuels has any noticeable impact”

          fixed that for you.

          Andrew Dessler and colleagues from Texas A&M University in College Station confirmed that the heat-amplifying effect of water vapor is potent enough to double the climate warming caused by increased levels of carbon dioxide in the atmosphere.

          But, I am not sure about the reputation of this website, its a government agency after all:
          http://www.nasa.gov/topics/earth/features/vapor_warming.html

        • Water vapor in the atmosphere is more commonly known as humidity. If you can see it, it’s called a “cloud” and sometimes it even “rains.”

          Burn every molecule of hydrogen that you could produce and the change to atmospheric water vapor will be below trivial. Three-quarters of the planet are covered with oceans that are constantly churning out a windstorm’s worth of water vapor to the fart’s worth that would be exhausted by hudrogen-fueled engines.

      • Most hydrogen is generated by cracking hydrocarbons with superheated steam. (Take a guess as to how said steam gets superheated…)

    • Hydrogen when produced on an industrial level is extracted from natural gas. Its cheaper and more efficient than hydrolysis.
      Just sayin.

        • And natural gas can be produced on an industrial scale, however, not in the quantities that would be required to replace that which is easily extracted from the earth. Several small towns in the midwest, currently inject waste from water treatment underground and then extract the gas that is produced to run the water treatment facilities. Not a sum zero operation, but it certainly has reduced operating costs as well as safely disposing/using a waste product.

    • Many years ago I saw plans for electric generation plants that relied on large tidal pools. These pools would fill automatically at high tide (no energy expense – the Moon does not send a bill) and at low tide the escaping water turned turbines to create electricity. Seems like a win-win to use water to make hydrogen from water that then turns into water vapor when it’s burned. The ONLY downside would seem to be controlling salt water corrosion.

      So long as the Moon hangs around up there you would have an essentially inexhaustible source of energy.

      • Another plan I recall used a portion of the energy of the escaping water to turn pumps that pushed a percentage of the water uphill to another holding pool, and so on to the altitude limit of practical local geography. Once all of the tanks were full to capacity the system could run almost continuously and not run out of energy between tides.

        Perhaps this was not pursued because it seemed an impractical way to provide electricity compared to fossil fuels, but it certainly seems like an ideal way to create and store hydrogen fuels.

      • Nope. Nice thought, but not really practical. Limited coastal areas and depths of tides. Not practical if you’re too far from the ocean due to transmission losses. And it would play absolute hell with the coastal ecosystems. Try selling this in California and see what happens.

        One refinement is to have the water turn the turbines on the inflow as well as the outflow. Still not enough though.

  9. What kind of .50 cal used might be a good question to ask. Just assuming that it’s a .50BMG may not be accurate.

  11. I really, really doubt that.

    I can personally vouch for M8 API and Mk. 211s going through inches of armor plate at 1,000 yards. Mind you, AR550 steel is a great many times tougher than ANY thin skin of carbon fiber.

    • The way composite material react to force, pressure, and impact is worlds different than steel armor plate. Not to mention that the specific type of round used wasn’t specified.

      I can believe it surviving one shot while not pressurized. A shot while pressurized, let’s just say I’m not sitting here waiting for the SAE paper to be published. Though an entertaining read it would be…

  14. Its really not hard to make a tank that can shrug off a .50bmg round, as long as its not AP. Aluminum liner tank and an inch of aerospace grade carbon fiber will do the trick. A second shot might be unhealthy. Compressed H2 stores really poorly, fill the tank with a metal hydride and the hydrogen capacity will exceed even cryogenic tanks. As a bonus, tank pressure is very low: the hydride needs to be heated to release the H2. A decade ago someone made a few prototypes that got tested with API ammo: a barely visible flame from expelled metal and tank bits before the fire went out. A compressed tank would look like a Michael Bay film, except that burning hydrogen is barely visible.

    • Metal hydride storage isn’t “there” yet. Theoretically you are correct that hydrides could store more than cryogenic tanks, but to my knowledge no one has been able to experimentally demonstrate that level of storage efficiency to date.

  15. My question is whether or not they shot a pressurized tank or not. I can see a tank surviving a .50 cal shot while not pressurized. Fill that sucker up and then see what happens…I’m not optimistic, but I am too busy working to put on my engineer hat right now.

    Sounds like a kick ass experimental mechanics project though. I should go get a Master’s degree 🙂

  16. Well, how hard did they throw the bullet at it?

    If they let some spindly engineer throw it I can believe it.

    Now, if they had a strapping high school math teacher such as myself throw it that tank wouldn’t stand a chance.

  17. While the doubters have their point about Which .50 cal round was used, the idea of having a very puncture resistant fuel cell is fantastic. Think about all the different applications non specific to hydrogen for such a device.

    While I’m no a tree huger, having an alternative fuel which has a byproduct of water vapor can only be a good thing. Personally, I think the whole green house gases/carbon dioxide debacle is a ruse but having automobiles that do not run off electricity and require suspect batteries which will ultimately cause even more headache than exhaust emission cannot be a bad thing.

    Sure, it’s a marketing ploy but anything that can boost my DuPont stock values (Kevlar) is fine with me.

    • I have heard a rumor that DuPont will no longer be able to sell Teflon pans in 2015. That might hurt their stock. Research and plan accordingly.

      • DuPont sold their Teflon business to the Japanese back in the 90s. The Japanese wanted Teflon because it is used it making filter bags for removing fly ash in coal fired plants. Also works well for removing particulates burning trash and waste as opposed to burying it.

        Non stick “Teflon” pans are not so great when folks use metal utensils in them and thus scratch their surface. Ruins them like washing a cast iron skillet… You just cannot possible make every item idiot proof enough to get it past a lawyer.

        Given enough time and effort, you can turn anything into an object which just is no longer feasible to use and too expensive to make.

  19. lol looks very strong, but definitely could not withstand a flush hit from a .50 BMG. If that were the case, the entire game of armor would be changed overnight and we’d be building Carbon Fiber Tanks as we speak.

    If they want to make it withstand car crashes a little better, just build a ‘cage’ around it that can compress/deform under severe impact stresses. But don’t blow smoke up my ass about it being able to deflect .50 BMG (as that is what is assumed by saying .50 cal, not a friggin musket ball).

  20. It says in the press release that the .50 cal armored piercing bullet was the one that penetrated. It was the multiple small caliber shots that did not. Or am I reading this wrong..the main article..
    From TTAG OP:
    Carter says that bullets from a small-caliber gun bounced off the carbon-fiber tanks, and that .50-caliber bullets barely made dents.”

    From their press release:
    They’re safe. In testing, we fired small-caliber bullets at the hydrogen tank and they just bounced off it. It took a 50-caliber armor-piercing bullet to penetrate the shell.

    Maybe I am reading all this wrong.

  21. dwb,

    I’m not sure what you were trying to do when you rewrote my post, other than perhaps fabricate the most blatant straw man argument ever. That being said, I agree with the statement you made, but it is irrelevant to this discussion.

    That article you linked to does absolutely nothing to support your claims. You claimed that H2O emissions are potentially worse than CO2 emissions. The article you provided only states that H2O is a greenhouse gas and interacts with CO2 to trap heat, something we already agree on.

    I’m talking about the magnitude of H2O emissions we could possibly create relative to the magnitude of the fluctuation in humidity on a DAILY basis (not seasonally). Not to mention the amount we could possibly create is still insignificant compared to the amount already there. I assert that the fluctuations are much bigger than the amount of H2O you add to the atmosphere from burning hydrogen, even if every car on the planet did. If the amount of H2O added to the atmosphere by people is substantially smaller than the amount of the daily fluctuation, I claim our contribution is insignificant to the total amount and therefore has as insignificant impact on global warming. If you have something to refute my claims I will gladly read it, but please don’t provide articles that don’t actually support your claims.

    I apologize if I misinterpreted your original argument, its hard to keep track sometimes.

  22. And this all ignores the more fundamental problem, namely, where are they getting the hydrogen? The only two ways I know of are as a byproduct of oil refineries or by electrolysis, which is ludicrous unless somebody could shut up the NIMBYs and build nuclear plants. And I know of one guy who says the most efficient way to store hydrogen is by attaching each four atoms to a carbon atom, and use methane.

  23. I’m actually surprised the 50BMG penetrated the tank.
    The wall thickness for a 70MPa tank, with a reasonable factor of safety of 2 (minimum) using a reasonable 3.5GPa tensile strength and a tank diameter of 50cm is >1cm, and would likely be 2-3x greater than that to account for multi-axial loading and a commercial 4x FOS. 2-3cm of carbon fiber composite will stop a 50BMG, as ~1″ thick carbon composite isn’t really a tank (pressurized) wall, its almost a tank (military vehicle) wall (ok, kidding, but its pretty much a composite armor thickness used for MG protection in APCs).

    The tank withstanding everything up to an AP 50BMG isn’t all that surprising really.

  24. OK, enough of this science talk. You may be blowing our cover. We are supposed to stupid paranoid white guys with little wienies. We are not supposed to be able to intelligently discuss issues like this, because, you know… we don’t have common sense.

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