Re: Il buco del Pentagono: un aggiornamento
Inviato da Tuttle il 9/1/2008 20:28:51
A sto punto si potrebbe discutere su un must datato che riunisce un po tutti i dubbi di cui si parla (l'articolo completo a mio avviso è pieno anche di inutili speculazioni):
2. Could the damaged wings have “telescoped” into the body of the aircraft, as claimed by the Dept. of Defence?
This claim was clearly meant for reporters, whose technical competence, as a general rule, would be unequal to the task of evaluating such a statement. There would have been no significant lateral force acting along either wing axis and there is no possibility of a wing actually entering the fuselage of the aircraft. If you fixed a Boeing 757 firmly to a given piece of ground, then used a team of bulldozers to push the wings into the body, the wings would merely fold up like an accordion or crumple and bend.
3. Could the wings have been entirely fragmented by the explosion of the fuel tanks after the aircraft struck the building?
The fuel tanks of a 757 are located under the fuselage, as well as in the wing roots. The entire fuel storage area of a 757 would easily fit inside the initial entry hole and, consequently, any explosion would have been largely confined to the building’s interior. As we shall see, the wings could not have entered the building, where they might possibly have encountered such a fate. The blast, as such, had little effect outside the building, as cable spools near the entry hole remained standing, for example.
4. This raises the question of whether the wings could have folded as the aircraft entered the building, bending backwards and following the aircraft in.
Except for fuel tanks, wiring and hydraulics, spars and ribs, wings are otherwise hollow. The spars could be described as locally rigid and globally flexible. In other words, a wing may flex (up and down) along its length when an aircraft encounters turbulence, for example, but, over much shorter distances, cannot bend significantly. Given sufficient force (applied either up or down) against a wing, it will simply break off. Sometimes the wings of older aircraft developed cracked spars. Even hairline cracks can be dangerous, as the slightest shearing force on the wing could widen and deepen the crack, causing catastrophic failure and the loss of a wing.
Of course, the force in question would not have been vertical, but horizontal. This makes the folding even more improbable, as the force of impact would be acting along the only possible fold axis, rather than at right angles to it. Try folding any material, say a piece of cardboard, by applying it’s edge (not it’s surface) to a tabletop. Folding horizontally is not an option, since all the spars would be lined up in opposing (momentarily) the folding force. Being locally rigid, the spars would simply snap within milliseconds of the impact against a support column that did not yield to their impact; they would fail as soon as the force of impact exceeded the elastic limit of the material. If they did not fail and if the support columns did not give way, the only remaining possibility would be for the aircraft to remain almost entirely outside of the Pentagon.
***
If a Boeing 757 struck the Pentagon in the manner described in the ASCE report, the port wing struck a column just to the left of the presumed engine-hole. Since the column did not fail, the wing must have, Here is why: The aircraft came in at 45 degrees to the wall of Wedge One and the port wing of a Boeing 757 is swept back at an angle of 29 degrees. Thus the angle made by the wing with the support column would have been
45 + 29 = 74 degrees
at the moment of impact. Clearly, no other portion of the wing could have been in contact with the Pentagon wall at that moment and the entire weight of the wing still, traveling at 500-plus miles per hour, would have produced a bending force that was entirely concentrated on the point of contact of the wing with the support column. This would have snapped all three spars instantly. The outboard portion of the wing would then have pivoted into the wall of the building, slamming into it but unable to penetrate it, because now the momentum of the wing, instead of being concentrated at one point, would have been distributed along the length of it contact with the building’s wall.
We can declare that this did not happen, since neither the port wing nor any significant portion of it was found outside the Pentagon on the morning of September 11, 2001.
About the authors
A. K. Dewdney is a mathematician and computer scientist who lives in London, Ontario, Canada.
G. W. Longspaugh is an aerospace engineer who makes his home in Fort Worth, Texas, USA.
http://physics911.net/missingwings
Cosa ne pensate?
2. Could the damaged wings have “telescoped” into the body of the aircraft, as claimed by the Dept. of Defence?
This claim was clearly meant for reporters, whose technical competence, as a general rule, would be unequal to the task of evaluating such a statement. There would have been no significant lateral force acting along either wing axis and there is no possibility of a wing actually entering the fuselage of the aircraft. If you fixed a Boeing 757 firmly to a given piece of ground, then used a team of bulldozers to push the wings into the body, the wings would merely fold up like an accordion or crumple and bend.
3. Could the wings have been entirely fragmented by the explosion of the fuel tanks after the aircraft struck the building?
The fuel tanks of a 757 are located under the fuselage, as well as in the wing roots. The entire fuel storage area of a 757 would easily fit inside the initial entry hole and, consequently, any explosion would have been largely confined to the building’s interior. As we shall see, the wings could not have entered the building, where they might possibly have encountered such a fate. The blast, as such, had little effect outside the building, as cable spools near the entry hole remained standing, for example.
4. This raises the question of whether the wings could have folded as the aircraft entered the building, bending backwards and following the aircraft in.
Except for fuel tanks, wiring and hydraulics, spars and ribs, wings are otherwise hollow. The spars could be described as locally rigid and globally flexible. In other words, a wing may flex (up and down) along its length when an aircraft encounters turbulence, for example, but, over much shorter distances, cannot bend significantly. Given sufficient force (applied either up or down) against a wing, it will simply break off. Sometimes the wings of older aircraft developed cracked spars. Even hairline cracks can be dangerous, as the slightest shearing force on the wing could widen and deepen the crack, causing catastrophic failure and the loss of a wing.
Of course, the force in question would not have been vertical, but horizontal. This makes the folding even more improbable, as the force of impact would be acting along the only possible fold axis, rather than at right angles to it. Try folding any material, say a piece of cardboard, by applying it’s edge (not it’s surface) to a tabletop. Folding horizontally is not an option, since all the spars would be lined up in opposing (momentarily) the folding force. Being locally rigid, the spars would simply snap within milliseconds of the impact against a support column that did not yield to their impact; they would fail as soon as the force of impact exceeded the elastic limit of the material. If they did not fail and if the support columns did not give way, the only remaining possibility would be for the aircraft to remain almost entirely outside of the Pentagon.
***
If a Boeing 757 struck the Pentagon in the manner described in the ASCE report, the port wing struck a column just to the left of the presumed engine-hole. Since the column did not fail, the wing must have, Here is why: The aircraft came in at 45 degrees to the wall of Wedge One and the port wing of a Boeing 757 is swept back at an angle of 29 degrees. Thus the angle made by the wing with the support column would have been
45 + 29 = 74 degrees
at the moment of impact. Clearly, no other portion of the wing could have been in contact with the Pentagon wall at that moment and the entire weight of the wing still, traveling at 500-plus miles per hour, would have produced a bending force that was entirely concentrated on the point of contact of the wing with the support column. This would have snapped all three spars instantly. The outboard portion of the wing would then have pivoted into the wall of the building, slamming into it but unable to penetrate it, because now the momentum of the wing, instead of being concentrated at one point, would have been distributed along the length of it contact with the building’s wall.
We can declare that this did not happen, since neither the port wing nor any significant portion of it was found outside the Pentagon on the morning of September 11, 2001.
About the authors
A. K. Dewdney is a mathematician and computer scientist who lives in London, Ontario, Canada.
G. W. Longspaugh is an aerospace engineer who makes his home in Fort Worth, Texas, USA.
http://physics911.net/missingwings
Cosa ne pensate?
Messaggio orinale: https://old.luogocomune.net/site/newbb/viewtopic.php?forum=3&topic_id=3983&post_id=109357