[escepticos] A vueltas con las torres gemela

[Chema Mateos <rinzewind@...>]

	Hola a todos:

	Encontré esto navegando por ahí y he pensado que quizá alguien
lo encuentre digno de destripar (o lo que sea). Está en inglés, pero
creo que no tiene demasiado problema de comprensión (lamento no ponerme
a traducirlo):

-----------------------------

THE WTC WAS DESIGNED TO SURVIVE
THE IMPACT OF A BOEING 767.

Fact. The twin towers were designed to withstand a collision with a
Boeing 707.

The maximum takeoff weight for a Boeing 707-320B is 336,000 pounds.
The maximum takeoff weight for a Boeing 767-200ER is 395,000 pounds.

The wingspan of a Boeing 707 is 146 feet.
The wingspan of a Boeing 767 is 156 feet.

The length of a Boeing 707 is 153 feet.
The length of a Boeing 767 is 159 feet.

The Boeing 707 could carry 23,000 gallons of fuel.
The Boeing 767 could carry 23,980 gallons of fuel.

The cruise speed of a Boeing 707 is 607 mph = 890 ft/s,
The cruise speed of a Boeing 767 is 530 mph = 777 ft/s.

So, the Boeing 707 and 767 are very similar aircraft, with the main
differences being that the 767 is slightly heavier and the 707 is
faster.

In designing the towers to withstand the impact of a Boeing 707, the
designers would have assumed that the aircraft was operated normally. So
they would have assumed that the aircraft was traveling at its cruise
speed and not at the break neck speed of some kamikaze. With this in
mind, we can calculate the energy that the plane would impart to the
towers in any accidental collision.

The kinetic energy released by the impact of a Boeing 707 at cruise
speed is
= 0.5 x 336,000 x (890)^2/32.174
= 4.136 billion ft lbs force (5,607,720 Kilojoules).

The kinetic energy released by the impact of a Boeing 767 at cruise
speed is
= 0.5 x 395,000 x (777)^2/32.174
= 3.706 billion ft lbs force (5,024,650 Kilojoules).

>From this, we see that under normal flying conditions, a Boeing 707
would smash into the WTC with about 10 percent more energy than would
the slightly heavier Boeing 767. That is, under normal flying
conditions, a Boeing 707 would do more damage than a Boeing 767.

In conclusion we can say that if the towers were designed to survive the
impact of a Boeing 707, then they were necessarily designed to survive
the impact of a Boeing 767.

So what can be said about the actual impacts?

The speed of impact of AA Flight 11 was 470 mph = 689 ft/s.
The speed of impact of UA Flight 175 was 590 mph = 865 ft/s.

The kinetic energy released by the impact of AA Flight 11 was
= 0.5 x 395,000 x (689)^2/32.174
= 2.914 billion ft lbs force (3,950,950 Kilojoules).

This is well within limits that the towers were built to survive. So why
did the North tower fall?

The kinetic energy released by the impact of UA Flight 175 was
= 0.5 x 395,000 x (865)^2/32.174
= 4.593 billion ft lbs force (6,227,270 Kilojoules).

This is within 10 percent of the energy released by the impact of a
Boeing 707 at cruise speed. So, it is also a surprise that the 767
impact caused the South tower to fall.

Overall, it comes as a great surprise that the impact of a Boeing 767
bought down either tower. Indeed, many experts are on record as saying
that the towers would survive the impact of the larger and faster Boeing
747. In this regard, see professor Astaneh-Asl's simulation of the crash
of the much, much larger and heavier Boeing 747 with the World Trade
Center. Professor Astaneh-Asl teaches at the University of California,
Berkeley.

Although the jet fuel fires have been ruled out as the cause of the
collapses, it should still be pointed out that the fuel capacities of
the Boeing 707 and the Boeing 767 are essentially the same. And in any
case, it has been estimated that both UA Flight 175 and AA Flight 11
were carrying about 10,000 gallons of fuel when they impacted. This is
well below the 23,000 gallon capacity of a Boeing 707 or 767. Thus the
amount of fuel that exploded and burnt on September 11 was envisaged by
those who designed the towers. Consequently, the towers were designed to
survive such fires. It should also be mentioned that other high-rise
buildings have suffered significantly more serious fires than those of
the twin towers on September 11, and did not collapse.

My question is: WAS THE WORLD TRADE CENTER BOUGHT DOWN IN A CONTROLLED
DEMOLITION? 

----------------------------

	Saludos:

	Chema.

-- 
               Chema Mateos - RinzeWind
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