[sdiy] Events in USA (the technical aspects of this whole thing)

[CHoaglin at aol.com]

Not sure if anybody's thought about it yet, but I think there was some 
engineering expertise behind this whole thing. Why? Well, because:

You don't knock over a 200,000 ton building with a 100-200 ton plane. There's 
just not enough kinetic energy there, and if there was enough KE to tear the 
building from its foundation (image the plane travelling at mach 3 or 
something and hitting a solid unyielding mass), the amount of energy needed 
to propel the plane through the building is < the energy needed to topple it, 
so the plane would go right through the building and out the other side. 
Plus, buildings are specifically designed to withstand lateral forces like 
wind shear and prevent toppling..some have integral mass dampers to do this, 
a several hundred ton weight in the top of the building, moved back and forth 
by hydraulic rams to compensate for the swaying of the building (I think the 
Chrysler building has one of these)

Rather, I think they estimated just how much airspeed they would need to get 
the plane through the exterior skin and supporting columns on one side of the 
building, but not propel it out the other side, leaving it inside the 
building.(though this could have been empirical, and we'll probably never 
know)

The choice of floors was probably no accident. Too low, and they couldn't get 
a trajectory that would take them in without crashing into something else. 
Too close to the top floor, and it just sets the top few floors on fire and 
damages the top of the reinforcing columns, allowing everybody else to 
evacuate and a greater chance of the building staying intact. Towards the 
middle of the building, and they get the plane ensconced inside the building 
and with a good deal of structural mass still above it, for the next step. 
Both planes hit at about the same level, as well.

The choice of planes wasn't an accident, I don't think. Most airlines use the 
same type of plane consistently for a given route, and one can look this up, 
it's even used as a selling point by the airline. Both 767's, a plane with a 
large fuel capacity. In other words, a bigger flying bomb. Structural steel 
starts to melt at the temperatures produced by burning jet fuel. Since 
skyscrapers hang all their floors from the outer supporting structure, once 
the supporting columns melt and buckle out the upper floors start dropping 
and hit the ones below them, knocking them out in a chain reaction until the 
entire structure is gone. I think a lot of thought went into this attack, and 
it (unfortunately) went exactly as intended. Brilliant from a technical 
standpoint, disgusting and reprehensible from any other. A friend of a friend 
of mine who I didn't know personally was apparently on flight 11, they're 
dead now.

-Chris
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