question about heavy aluminum tubing

[zmzmzm]

On 9/11 an aluminum tubing light pole is said to have pierced the windshied of a taxicab near the Pentagon.

Here are links to two views of the pole after it is said to have been removed from the taxicab:





Here is a description of the pole:

The pole was straight originally. The lamp head is 40 feet off the ground, and the straight main light pole looks to be about 37 feet long, is tapered from 10 inches at the bottom to 6 inches at the top, and is extruded from 1/8 inch thickness aluminum. The original pole weighs 247 pounds, with 20 pounds for the truss arm assembly and 70 pounds for the lamp head added, to give a total weight of 337 pounds for each light pole standing there, before the 180,000 pound (90 ton) aircraft allegedly hit them at 535 mph. (784.8 feet per second (fps))

In the photo, the upper part of the pole is bent in a very smooth radius. Is this the way an unheated aluminum pole would be expected to respond to being violently struck near the top?

It would seem to me, that a strike at 500 mph to a cold aluminum tube might create a crease on the side away from the strike, resulting in an angular deformation. I cannot picture a cold aluminum tube being struck at 500 mph and bending in a beautiful, smooth arc.

[johnptc]

check the poles in the background still standing they are all nicely curved :confused::confused:

[jeremy k]

ZMZM - if that post was hit high on top - it would take on a slight nice bend as it
has - just like if you take and hold a pencil by the ends and flex it. I'm talking about the bottom section as you can see the base plate on the end of the pole that is bent. - JK

[Frosty]

I don't know what you're seeing. I retired from AK DOT highway's maint and have seen luminair poles that have been knocked down in all kinds of shapes from smooth curves to crumpled to shredded to looking almost new.

I see nothing odd about the one in the picture at all.

Frosty

[arftist]

First of all, it was not extruded from 1/8" aluminum, all aluminum that is extruded is formed from a solid billet. Second, the complete lamp post also is not 1/8" thick, more like 5/8"-3/4", and like all extrutions, made to exact and highest grade specifications. Finaly there is absolutly no way to predict how random destruction will appear.