3 ms·

1) kinetic energy and momentum ... and jet fuel 2) don't ask me what the point is, as long as some people can envision a point to it, it's irresponsible to not

1) kinetic energy and momentum ... and jet fuel 2) don't ask me what the point is, as long as some people can envision a point to it, it's irresponsible to not avoid such a situation. don't ask me what the point is, ask the hijackers of https://en.wikipedia.org/wiki/Southern_Airways_Flight_49 https://en.wikipedia.org/wiki/Southern_Airways_Flight_49

jojobas 6y ago
Dry storage casks are embedded in some seriously thick concrete for radiation shielding. I wouldn't be surprised if a direct hit of an A-380 engine at Mach 1 didn't actually destroy it. Again, if you have a highjacked plane on hand you can cause way more damage by crashing it into a skyscraper than some nuclear waste storage - it's a somewhat different risk but not a greater one.
- DoctorOetker 6y ago
  How thick? Check out these, with humans for comparison: https://en.wikipedia.org/wiki/File:Nuclear_dry_storage.jpg https://en.wikipedia.org/wiki/File:Nuclear_dry_storage.jpg
  - jojobas 6y ago
    Some 70 cm. That's right, about half of diameter of these cylinders are concrete walls. For comparison, Schwerer Gustav shells weighed about the same as A380 engine, were mostly hardened solid steel, arrived on target at about Mach 2 and could penetrate some 7 meters of concrete (including the explosive charge). You can help yourself to a F-4 vs concrete test that doesn't really make a dent in about 1m of concrete.
    - DoctorOetker 6y ago
      From that video (F4 vs concrete), the narrator who was present at the test says that ultimately its the energy that counts (wheither you model a detailed plane colliding, or a simple sausage shape of same mass and velocity, turns out you get essentially the same result). So let's calculate the kinetic energy for the 3 things mentioned: the Phantom F4 II kinetic energy, the Schwerer Gustav shell kinetic energy (I don't know the energy in the explosive charge though) and the A380 kinetic energy: E = 1/2 * m * v * v (not sure how to use caret in markdown) Phantom F4 II: 1/2 18,824 kg (770 / 3.6 m / s) (770 / 3.6 m / s) = 430 MJ Schwere Gustav shell: 1/2 7000 kg 343 m / s 343 m / s = 412 MJ EDIT: this should be 4 x 412 MJ = 1.6 GJ since I forgot to double the speed of sound. A-380: 1/2 500000 kg ( 945 / 3.6 m / s ) ( 945 / 3.6 m / s ) = 17.226 GJ where I used 500 tonnes instead of max takeoff weight of 575 tonnes, and V MO of 945 km/h so thats 40 x more energy than the F4 test... the F4 test resulted in a 6 cm deep scratch, so naively multiplying by 40 gives 2.4 m , i.e. substantially more than 70 cm (to see it's not that naive, just consider crashing 40 F4's sequentially, they'll dig deeper and deeper)
      - jojobas 6y ago
        Your calculation is flawed, probably intentionally. A-380 is not a shell, it's a soft sausage 70 meters long. The fuselage collision would be stretched in time, greatly diminishing impact forces. It's large cross-section means it couldn't even focus on a single cask. The 40 F-4s analogy is incorrect again, as the tail of the plane wouldn't be hitting the target, it would be hitting the soft pile of crap from the nose and midsection. The engine is the only dangerous part as far as collisions against concrete go, and even then not so dangerous. Again, let's say we got unlucky and the 4 engines of an A-380 breached 4 casks. Would it be bad? Of course. Would it be as bad as 9/11? No way. The fireball would lift some dust in the air and quickly dilute it. Nuclear fuel is essentially ceramic and doesn't melt until 2800C, way above what jet fuel can do (steel beam anyone?). Some fission products would be included in the cloud. Local decontamination effort would be many orders of magnitude below that of Chernobyl (where health effects on cleanup workers proved impossible to measure) and probably on par with 9/11 cleanup.

jojobas 6y ago

Dry storage casks are embedded in some seriously thick concrete for radiation shielding. I wouldn't be surprised if a direct hit of an A-380 engine at Mach 1 didn't actually destroy it. Again, if you have a highjacked plane on hand you can cause way more damage by crashing it into a skyscraper than some nuclear waste storage - it's a somewhat different risk but not a greater one.

DoctorOetker 6y ago
How thick? Check out these, with humans for comparison: https://en.wikipedia.org/wiki/File:Nuclear_dry_storage.jpg https://en.wikipedia.org/wiki/File:Nuclear_dry_storage.jpg
- jojobas 6y ago
  Some 70 cm. That's right, about half of diameter of these cylinders are concrete walls. For comparison, Schwerer Gustav shells weighed about the same as A380 engine, were mostly hardened solid steel, arrived on target at about Mach 2 and could penetrate some 7 meters of concrete (including the explosive charge). You can help yourself to a F-4 vs concrete test that doesn't really make a dent in about 1m of concrete.
  - DoctorOetker 6y ago
    From that video (F4 vs concrete), the narrator who was present at the test says that ultimately its the energy that counts (wheither you model a detailed plane colliding, or a simple sausage shape of same mass and velocity, turns out you get essentially the same result). So let's calculate the kinetic energy for the 3 things mentioned: the Phantom F4 II kinetic energy, the Schwerer Gustav shell kinetic energy (I don't know the energy in the explosive charge though) and the A380 kinetic energy: E = 1/2 * m * v * v (not sure how to use caret in markdown) Phantom F4 II: 1/2 18,824 kg (770 / 3.6 m / s) (770 / 3.6 m / s) = 430 MJ Schwere Gustav shell: 1/2 7000 kg 343 m / s 343 m / s = 412 MJ EDIT: this should be 4 x 412 MJ = 1.6 GJ since I forgot to double the speed of sound. A-380: 1/2 500000 kg ( 945 / 3.6 m / s ) ( 945 / 3.6 m / s ) = 17.226 GJ where I used 500 tonnes instead of max takeoff weight of 575 tonnes, and V MO of 945 km/h so thats 40 x more energy than the F4 test... the F4 test resulted in a 6 cm deep scratch, so naively multiplying by 40 gives 2.4 m , i.e. substantially more than 70 cm (to see it's not that naive, just consider crashing 40 F4's sequentially, they'll dig deeper and deeper)
    - jojobas 6y ago
      Your calculation is flawed, probably intentionally. A-380 is not a shell, it's a soft sausage 70 meters long. The fuselage collision would be stretched in time, greatly diminishing impact forces. It's large cross-section means it couldn't even focus on a single cask. The 40 F-4s analogy is incorrect again, as the tail of the plane wouldn't be hitting the target, it would be hitting the soft pile of crap from the nose and midsection. The engine is the only dangerous part as far as collisions against concrete go, and even then not so dangerous. Again, let's say we got unlucky and the 4 engines of an A-380 breached 4 casks. Would it be bad? Of course. Would it be as bad as 9/11? No way. The fireball would lift some dust in the air and quickly dilute it. Nuclear fuel is essentially ceramic and doesn't melt until 2800C, way above what jet fuel can do (steel beam anyone?). Some fission products would be included in the cloud. Local decontamination effort would be many orders of magnitude below that of Chernobyl (where health effects on cleanup workers proved impossible to measure) and probably on par with 9/11 cleanup.