Aluminium alloys are used extensively in aircraft due to their high strength-to-weight ratio. On the other hand, pure aluminium metal is much too soft for such uses, and it does not have the high tensile strength that is needed for airplanes and helicopters.
Aluminium alloys versus types of steel
Aluminium alloys typically have an elastic modulus of about 70 GPa, which is about one-third of the elastic modulus of most kinds of steel and steel alloys.
One third the strength is more than strong enough to break it under such conditions; there's a FEA proving it. Water can also cut through steel if thrown at a bigger speed and in a thin jet (google waterjet cutting), and it's not even a solid. The principle is the same: kinetic energy.
It adds density to the wing as a whole, thus increasing the mass, and with it, the kinetic energy.
Imagine yourself throwing an empty soda can to a glass. You will probably not hurt it. Now imagine yourself throwing it full. You will probably break it. Same material, different overall density.
And an airplane is much more than the sheeting. Focusing on the cover and forgetting about the structure is a lie by omission. Remember the wings must be strong enough to support the weight of the fuselage.
These two sheets look like they bent post-impact, due to the load. They bent east-west because it was far easier for them to bend east-west than north-south, due to their orientation and shape (a very oblong rectangle, i.e. basically, a sheet of steel with its faces pointing north and south).
However I think that parts of that picture show that the wing was pulled towards the hole by its own structure as the plane penetrated. Good catch.
So aluminum sheeting wouldn't be shredded by the two sharp steel knives it impacted on each column? What kept the jet together long enough for the wing to "pull" the denser, thicker, stronger steel inwards? According to the official story the wings disintegrated as they cut through the tower, which means at the point the engines entered the building, the wing tips weren't even attached to the rest of the plane, yet we don't see them bounce off, we see them continue at the same speed as the rest of the plane.
I guess in Randi world the wing tips carried the mass of the jet whether or not they still were attached?
So aluminum sheeting wouldn't be shredded by the two sharp steel knives it impacted on each column? What kept the jet together long enough for the wing to "pull" the denser, thicker, stronger steel inwards? According to the official story the wings disintegrated as they cut through the tower, which means at the point the engines entered the building, the wing tips weren't even attached to the rest of the plane, yet we don't see them bounce off, we see them continue at the same speed as the rest of the plane.
I guess in Randi world the wing tips carried the mass of the jet whether or not they still were attached?
Why are you worried about the aluminium sheeting? The aluminium alloy that makes the wing spars and was behind the sheeting is much stronger. Let me quoting the WP article again so it hopefully sticks:
Aluminium alloys are used extensively in aircraft due to their high strength-to-weight ratio. On the other hand, pure aluminium metal is much too soft for such uses, and it does not have the high tensile strength that is needed for airplanes and helicopters.
The wing tips carried their own mass. In one of the frames of a video, I see one of them clearly behind its initial position, i.e. bent backwards. Unfortunately we don't have a high speed camera closeup of the wing impact, for obvious reasons, so inferring such details from any of the footages is risky to say the least.
Why does that matter? The kinetic energy (which is what breaks atomic bonds, not weight) of the plane was in the order of 1t of TNT, and a FEA has proved how that cutting is produced. You can get information on that here: http://web.mit.edu/civenv/wtc/PDFfiles/Chapter IV Aircraft Impact.pdf
To break the chemical bonds that keep the steel together, you need energy. That energy can come from many possible sources, one of them being kinetic energy due to mass and velocity. These two properties are what enable planes and water to cut through steel.
Your turn.
Why does the weight of the steel matter here, other than as an argument that favors inertia and thus cutting? Why are you neglecting to take into account the energy of the impact, which is what breaks chemical bonds? Why do you neglect to take into account the spars that were behind the sheeting as if the sheeting was the strongest structural member of the plane?
Here's a closeup of the far right of the gash showing westward bends:
How much mass was in the wing tip at that point? Was there any fuel left? What is your calculation of the momentum of the wing tips? How is the east-west damage consistent with a north south impact of a wing tip no longer attached to the rest of the jet?
Why are you worried about the aluminium sheeting? The aluminium alloy that makes the wing spars and was behind the sheeting is much stronger. Let me quoting the WP article again so it hopefully sticks:
Aluminium alloys are used extensively in aircraft due to their high strength-to-weight ratio. On the other hand, pure aluminium metal is much too soft for such uses, and it does not have the high tensile strength that is needed for airplanes and helicopters.
Polaris already answered that in a wonderfully concise way.
The wing tips carried their own mass. In one of the frames of a video, I see one of them clearly behind its initial position, i.e. bent backwards. Unfortunately we don't have a high speed camera closeup of the wing impact, for obvious reasons, so inferring such details from any of the footages is risky to say the least.
Why does that matter? The kinetic energy (which is what breaks atomic bonds, not weight) of the plane was in the order of 1t of TNT, and a FEA has proved how that cutting is produced. You can get information on that here: http://web.mit.edu/civenv/wtc/PDFfiles/Chapter IV Aircraft Impact.pdf
To break the chemical bonds that keep the steel together, you need energy. That energy can come from many possible sources, one of them being kinetic energy due to mass and velocity. These two properties are what enable planes and water to cut through steel.
Your turn.
Why does the weight of the steel matter here, other than as an argument that favors inertia and thus cutting? Why are you neglecting to take into account the energy of the impact, which is what breaks chemical bonds? Why do you neglect to take into account the spars that were behind the sheeting as if the sheeting was the strongest structural member of the plane?
Other than the fact a mostly hollow aluminum plane would have been shredded like a head of iceberg on a lettuce slicer, I can't think of anything.
No wait - how about that even if they were super-duper reinforced steel-slicing jets that were somehow still light enough to fly at 500 MPH 1000 feet above seal level, they are not noted for turning on a dime, so missing the target was quite likely?
Naah...despite the damage evidence and the proof of the last 12 years of torture, war and loss of liberty, a jet is the obvious answer. Nothing to see here, everyone back to work.
Other than the fact a mostly hollow aluminum plane would have been shredded like a head of iceberg on a lettuce slicer, I can't think of anything.
No wait - how about that even if they were super-duper reinforced steel-slicing jets that were somehow still light enough to fly at 500 MPH 1000 feet above seal level, they are not noted for turning on a dime, so missing the target was quite likely?
Naah...despite the damage evidence and the proof of the last 12 years of torture, war and loss of liberty, a jet is the obvious answer. Nothing to see here, everyone back to work.
This is the Educational forum.
There's been any number of instances where the impetus towards education has been provided, yankee.
Try it, you might like it.
This is the Educational forum.
There's been any number of instances where the impetus towards education has been provided, yankee.
Try it, you might like it.
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