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but that is EXTREMELY important

how do people in engineering design things?  from previous experience

how do they know how things behave in certain conditions?  from previous experience

I once had to test a certain type of bearing seal called an air seal that exists in the hot part of the engine and supports the power shaft in some turboshaft engines.  The seal worked most of the time, but nobody who had worked with it over years and years could tell me where the high pressure and low pressure areas were, ie, how the seal actually worked.  It worked, that's all.  

A lot of engineering is like that - you design something and hope it works.  You don't necessarily put instruments all over the place and figure out how it works.

Same thing when something ruptures.  Most engineers don't care about anything at the molecular level.  They just want to know under what conditions it will happen.

So the fact that it has never happened before, and it happened TWICE, both times on 9-11, and not anytime since then, when planes have hit buildings before, makes it extremely suspicious and that is what should be investigated, not the 10,000 times or more that it didn't happen.

by manon (m@gmail.com) on Fri Sep 15th, 2006 at 05:06:42 PM EST
[ Parent ]
This is a big part of this threads wildness. And not only this thread.

In general we do not have mathematical proof for stuff we know that we know. Neither do we always have an reference handy (not even with the help of google). Be it engineering or the access to firewood in Sweden. And getting challenged on stuff we know that we know, that are basic, does not prompt eagerness to prove it, for what proofs would be acceptable for those that does not share our knowledge? And then a "you prove it - no you prove it" is quickly started.

Therefore I am not sure this debate over Pentagon will lead anywhere. On the other hand I would be interested in a diary on what plane crashes into objects usually look like. I know formulating it would probably mean some work for you (it is that way with knowledge we normally use rather then describe) but I think it would be interesting. If you like to compare it with 911 is up to you.

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by A swedish kind of death on Fri Sep 15th, 2006 at 09:38:53 PM EST
[ Parent ]
Great suggestion. And may I add a diary on how buildings collapse. I'm thinking about the "pancake" theory which explains the collapse of the twin towers.
Note: very important for that matter would be to know the actual structure of the centre of those towers (or an estimation of it), and an estimation of the temperature inside after the attack (as a function of time). these "parameters" could be given as an appendix or as a separate thread.

that would be extremely nice. I know nothing about structural mechanics.

by findmeaDoorIntoSummer on Sat Sep 16th, 2006 at 06:28:48 AM EST
[ Parent ]
The "basic" report is here....(quite a lot of pdf files)!

An important point would be the "B.4.3 Floor Truss Seated End Connections at Spandrel Beam and Core" chapter... As it would seem that some of those connectors were supple (as design) and couldn't be fireproofed very well... ?

An audio-slide show shows for the layman the whole story !

"What can I do, What can I write, Against the fall of Night". A.E. Housman

by margouillat (hemidactylus(dot)frenatus(at)wanadoo(dot)fr) on Sat Sep 16th, 2006 at 08:56:17 AM EST
[ Parent ]


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