paranoid ?
in [ASM]
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From: Rod Pemberton on 22 Jan 2008 15:36 "Evenbit" <nbaker2328(a)charter.net> wrote in message news:46f90698-4860-4adb-b0a4-95723872b9fa(a)e25g2000prg.googlegroups.com... > On Jan 19, 4:10 pm, "Rod Pemberton" <do_not_h...(a)nohavenot.cmm> wrote: > > "Evenbit" <nbaker2...(a)charter.net> wrote in message > > > > news:e9c9170c-3c33-4a55-bdff-0c710d285930(a)v46g2000hsv.googlegroups.com... > > > > > On Jan 18, 9:25 pm, "Rod Pemberton" <do_not_h...(a)nohavenot.cmm> wrote: > > > > > > I agree. Why does everyone seem to think I mentioned a .45? > > > > > Because it is the absolute minimum one needs for effective self- > > > defense. Anything less is useless... you might as well be carrying a > > > beebee gun, paint gun, or water pistol. > > > > I agree that .45 is the best available pistol round for self-defense, but I > > beg to differ with it being the "absolute minimum." I personally believe > > .308 Winchester is the rough minimum required for _effective_ self-defense. > > Please remember that within the definition for "effective" the term > "reliable" is implied. You do not want to take the chance of the "bad > guy" standing up again. > Exactly. That's why a .308 rifle round, which can penetrate a vest, is better than .45 pistol round which can't... > > I have a fairly large family. I haven't met most of them, but, due just to > > size, one can assume that there are both cops and crooks. If one or the > > other from my own family shows up on my doorstep, it's likely they'll be > > wearing a vest since I don't view them as poor, stupid, etc. That means, > > without taking into account non-family elements of society, I need to be > > able to "pop" a vest for realistic home or personal defense. Now, given > > No. The requirement of >= .45 is not for "popping" a vest. If he's got a vest on, a .45 ACP is useless... It'll be stopped by the vest each and everytime, unless you get lucky and hit the same spot... Can you imagine unloading an entire high capacity clip, say 14 rounds for a Para Ordnance 1911, and the guy still coming at you? And, having to reload? When one high power rifle round will stop the guy completely, permanently, even with a vest? > If the > "bad guy" is "spaced-out" on drugs, he can likely ignore a small wound > from a smaller weapon and will continue the attack -- and be more > determined to succeed this time. Using a .45 or .50 will increase the > odds that he will stay on the floor. > Vest or not, he's much more likely to get off the floor with a .45 ACP than a .308 Winchester. The .308 Winchester rifle round is far more powerful than .45 ACP or .50 pistol rounds. He's less likely to get up when shot with a rifle round capable of taking down deer, bear, moose, and can puncture a vest if he's got one on, than a .45 ACP which might be fine for wild hogs but not larger. Ballistic gelatin for an above average .45 ACP round: http://www.handgunsmag.com/ammunition/dpx_022305/ Ballistic gelatin for an above average .308 Win round: http://www.barnesbullets.com/information/bullet-talk/x-citing-facts/ No comparison. The .308 does 4-5 times the damage. Rod Pemberton
From: Robert Redelmeier on 22 Jan 2008 23:16 Evenbit <nbaker2328(a)charter.net> wrote in part: > Robert Redelmeier wrote: >> I'm not sure I do, but if any ammunition is, it probably should >> be frangibles. Glasers are one brand that was specifically >> designed for use in aircraft in the 1960s. Essentially these >> are canister rounds -- a very thin bullet shaped can holding >> small shot in oil. The can might be able to penetrate light >> clothing intact but probably not 3mm plastic. > Horse manuer! > The Glaser design is a known "armour-piercing" "cop-killer" > bullet. Politicians used it as an excuse to push for more > restrictions on arms imports/civilian access. What? Are you saying politicians were right? In point of fact, they are not. Glasers penetrate fewer layers of Kevlar than FMJ. Furthermore, Kevlar vests didn't exist until 1976, while Glasers were released 1975. They couldn't have been designed against vests. -- Robert
From: Robert Redelmeier on 22 Jan 2008 23:37 Rod Pemberton <do_not_have(a)nohavenot.cmm> wrote in part: > They're usually placed over the fuel tank. How could attackers so reliably situate the explosives? Shouldn't there be a number of duds where bombs went off not close enough to the CWT? OTOH, they can reliably place explosives near the pressure hull. Even if the device were in direct contact with the CWT, I doubt it would cause any fire or explosion. Hydraulic hammer could be caused. Lots of saboteurs have blasted storage tanks without causing fires. Explosives are actually used to snuff out oilwell fires. I think even the Hollywood special effects 1/4 stick dynamite + 1 gallon gasoline devices need a separate igniter for reliability. And gasoline is flammable, while jet fuel is only combustible (needs a serious starter). > IIRC, military planes have nitrogen (instead of air) in the fuel tank, Inerting is routinely done on stationary tanks, mostly to prevent fuel degradation/oxidation or vapour loss. But I've never heard of it being done on aircraft. How do they back-fill for the fuel used? Small LN tank? I highly doubt it. > and so the vaporized fuel can't cause a fire or be used as > an explosive. Jet fuel isn't particularly flammable unless you get it hot. And I've never heard of any explosion with it. Nor it is used in making FAEs (Fuel-Air explosives). Even gasoline is a bit heavy. > In the fuel tank there is a mix of > a volatile fuel and oxidizer (20% of air as oxygen). Jet isn't volatile enough to flash below 140'F. > I'm not sure about airplane fuel oil, but for gasoline the > energy released increases exponentially with compression. Wrong. Energy release is entirely dependant on extent of combustion. Power recovered in an Otto cycle engine depends on compression ratio. > The chart I saw many years ago on gasoline energy release > vs. compression went upto an 18:1 compression ratio. Yep, sounds like an Otto cycle (gasoline spark ignition) engine. > The chart didn't say if it was regular commercial gasoline or > high octane racing fuel. It makes very little difference. High octane fuel just withstands heat better without autoigniting, so can be run to higher compression ratios without knocking. > gone much higher. Essentially, gasoline is capable of bomb > like energy releases without increasing the percentage of > oxydizers (20% for air) to the mix, such as nitrous oxide > (33% oxygen) or pure oxygen. Only when very carefully mixed with air. The military have been working FAEs for 30+ years and still don't have them especially reliable. > Gasoline is also known to release more energy with a > slight amount of water or moisture. This has been used in > automotive engines Yes, for cooling during the compression cycle to tolerate higher compression ratios. -- Robert
From: Rod Pemberton on 23 Jan 2008 16:13 "Robert Redelmeier" <redelm(a)ev1.net.invalid> wrote in message news:vwzlj.167$Ej5.160(a)newssvr29.news.prodigy.net... > Even if the device were in direct contact with the CWT, I > doubt it would cause any fire or explosion. .... > Explosives are actually used to > snuff out oilwell fires. True, but they are using multiple oil barrels packed with dynamite to put out a relatively small fire by comparison to the explosion. The relatively massive explosion consumes all combustible oxygen. By comparison, for airplane explosion, you have a small explosion with a large volume of vapors. Only a samll fraction of the entire oxygen supply is being consumed. Basically, just energy needed to initiate (or attempt to initiate) an explosion is being transferred to the fuel vapor. > And gasoline is flammable, > while jet fuel is only combustible (needs a serious starter). Gasoline is explosive at low pressure under certain circumstances. At the moment, I can't seem to find the explosive limits of gasoline vapor with water vapor... only with air. According to the upper and lower explosive limits for jet fuel in air, it has similar characteristics to gasoline with air: Gasoline: 1.4% LEL, 7.6% UEL (NIOSH) Jet A: 0 to 1% LEL, and 6 to 7% UEL (Boeing) > > IIRC, military planes have nitrogen (instead of air) in the fuel tank, > > Inerting is routinely done on stationary tanks, mostly to prevent > fuel degradation/oxidation or vapour loss. But I've never heard of > it being done on aircraft. How do they back-fill for the fuel used? > Small LN tank? I highly doubt it. No idea. Perhaps, they pressurized fuel tank with it? It'd be a serious problem if it created an increasing vacuum as the fuel is consumed... FWIW, an FAA or NTSB official said the military has for decades when explaining some airplane fuel tank explosion to the public. I haven't searched for info on this. I'd assume if the military is involved, it's probably classified no matter how mundane... > Jet fuel isn't particularly flammable unless you get it hot. > And I've never heard of any explosion with it. Nor it is used in > making FAEs (Fuel-Air explosives). Even gasoline is a bit heavy. In fact, there was TV show a few months ago, where NTSB officials claimed there are hundreds of airplanes accidents resulting from fuel tank explosions, including many they were reclassifying now that they understood the issue. As for gasoline, you only need watch video of firefighters (unintentionally) blowing a few thousand sq-ft house to pieces, as shown by a recent TV show. "He just took a house to the face!" They planned of training on an actual house scheduled for demo, instead of the usual "firehouse." They used an "accelerant" to ensure a constant burn speed of the house. Supposedly, the "accelerant" wasn't supposed to have gasoline in it. I believe they used straight gasoline. You can hear one firefighter say, "OK, I smell gasoline...," right before they light it up. They put it in the basement where it was supposed to help create a widespread and even burn of the house. But, I believe the basement was full of moisture and they waited to the point that all the gas had vaporized. Supposedly, it was equivalent to a few sticks of dynamite... Since a gallon of gasoline is equivalent to 14 sticks of dynamite (DOE figures), and only assuming the upper explosive limit of slightly less than 8% (minimum vapor of gasoline required), they poured at least 4-5 gallons of gasoline around. At the lower limit, they could've poured upto 40 gallons... Perhaps, it's less: "...vapor of one cup of gasoline has the explosive power of about five pounds of dynamite." (CDC NASD) That would indicate maybe two gallons minimum. With my basic understanding of physics and chemistry, I see no reason why an airplane fuel tank, with oxygen, moisture, couldn't create a similar scenario. > > I'm not sure about airplane fuel oil, but for gasoline the > > energy released increases exponentially with compression. > > Wrong. Correct (below). > Energy release is entirely dependant on extent of combustion. Wrong (below). > Power recovered in an Otto cycle engine depends on compression > ratio. Your statements are correct for a given fixed compression, but wrong when comparing different compression ratios. The reason is chemistry. Gasoline starts from oil which has over 100,000 compounds. Gasoline is a complex and random mix of hundreds of hydrocarbons (aromatics, alkanes, alkenes, cycloalkanes) some easy to combust, some difficult. The chemical reactions that occur between oxygen and the hydrocarbons change depending on the compression. There a literally hundreds of different chemical reactions which occur depending on the mix of hydrocarbons and compression. Basically, a more efficient set of chemical reactions occur when the compression is increased, because harder to burn hydrocarbons (more stored energy) react more completely (more released energy) with oxygen. > > Gasoline is also known to release more energy with a > > slight amount of water or moisture. This has been used in > > automotive engines > > Yes, for cooling during the compression cycle to tolerate > higher compression ratios. You're referring to "water injection." I was referring to "gasoline water emulsions." Water in gasoline has been shown to prevent knock, slow combustion, reduced nitrous oxides, release more energy combustion, other effects. You only need to be aware of the effects of the firefighter's exploding house. The moisture involved had nothing to do with cooling or compression. Perhaps it delayed combustion, perhaps it made combustion more efficient, perhaps it actually takes part in the combustion like in a thermite reaction, you'd have to consult a chemist, but the effect is there. You can notice the effect yourself on any low end vehicle produced by the (former) big three. Ever notice an increase in engine power on hot high humidity days? It's not doing anything to cool the intake charge there either... but, it is affecting combustion in a way that increases power. BTW, you can also notice the effect of a denser air charge on a cold day with any low end vehicle produced by the (former) big three. Rod Pemberton
From: Evenbit on 23 Jan 2008 23:18
On Jan 22, 11:16 pm, Robert Redelmeier <red...(a)ev1.net.invalid> wrote: > Evenbit <nbaker2...(a)charter.net> wrote in part: > > > Robert Redelmeier wrote: > >> I'm not sure I do, but if any ammunition is, it probably should > >> be frangibles. Glasers are one brand that was specifically > >> designed for use in aircraft in the 1960s. Essentially these > >> are canister rounds -- a very thin bullet shaped can holding > >> small shot in oil. The can might be able to penetrate light > >> clothing intact but probably not 3mm plastic. > > Horse manuer! > > The Glaser design is a known "armour-piercing" "cop-killer" > > bullet. Politicians used it as an excuse to push for more > > restrictions on arms imports/civilian access. > > What? Are you saying politicians were right? In point of > fact, they are not. Glasers penetrate fewer layers of Kevlar > than FMJ. > > Furthermore, Kevlar vests didn't exist until 1976, while > Glasers were released 1975. They couldn't have been designed > against vests. > The mass-media "hatchet jobs" at the time (the Clinton era) made no mention of the Glaser brand -- but the bullet under discussion was clearly the same. Their use of "cop killer" in the headline was a clear indication of their intent to "demonize" any bullet of an unusual construction. Nathan. |