Armilla, I think that your back-of-the envelope calcs are probably more sensible than the calcs in the site you referred to, because your calcs allowed for some debris being retained in the building, and some escaping.
The “force on the building” approach using momentum is flawed. The impact force isn’t comparable to wind loading. The impact didn’t cause a uniform deformation over the entire structure, it broke things.
Quite true. The physics of the actual collision must be mind-bogglingly complex when you take into account the effects of the fuel explosion, the actual structure of the tower with its load bearing core and suspended walls and the distribution of the debris.
The wind loading is the day-to-day stress the building is designed to withstand, and no doubt has a large safety margin, but I think it helps to put the forces of the collision into some perspective since it’s pretty hard to visualise the sheer scale of the impact.
I think Armilla has the physics pretty well nailed on this. But what brought the towers down was the fire. Obviously the terrorists knew that going twice as fast has four times the energy, but if those planes weren’t full of fuel the towers would have stood.
Um, IANA physicist, but if he drilled a plane into the ground from altitude at 700 mph, how is it that a note survived the crash? Not to mention skin still stuck to the trigger?
My “oh come on” alarms are going off.
In other words–cite?
That hijacking/crash is well documented. The note surviving wasn’t the hard part (a piece of paper doesn’t have a lot of momentum even going 700 mph because it still has very little mass). Finding it was, but they did. And the remains of the revolver with a bit of the guy’s skin on it.
They knew what to look for because they heard what happened on the CVR.
How did they know the final shot was suicide?
Peace,
mangeorge
There must be laws to stop terrorist from flying hijacked planes TOO FAST for conditions! Take away their pilots license at least.
They needed more training perhaps. They endangered all those passengers lives.
Way too much thinkin’ goin on here, but it is interesting.
The planes were destined to disintigrate no matter how fast or slow or how high or how low with those maniacal operators.
All safety procautions went out the window that morning.
Just a quick thought. What did the most damage to the building at the moment of inpact ? I thought a plane is mostly light aluminium foil with some hard parts (engines) attached. Even a large plane couldn’t damage the core structure of such a building, because it would just crumple up. Isn’t the damage done from the only part that wasn’t compresable, the fuel, entering the building at very high speed, and acting as a high pressure pump ?
Ever seen the photo of a straw driven into a tree by a tornado? Or of the 2X4 sticking out of the side of a brick wall? At high enough speed, it pretty much doesn’t matter what something’s made out of, it’s going to go through whatever it hits.
Flying that quickly, were they using only naked eye sight to guide the planes in to the towers?
Both planes hit almost dead middle… Being off just a few cm when 500 yards away would result in a miss, and flying so fast, would be hard to correct?
tcdaniel
Um, I’m not sure what you’re criticizing here. The OP was asking if the plane might have come apart before it hit (i.e. the terrorists might have failed), and the general concensus is no.
Beastal
For their (believe me, no pun intended) final approach, yes, they did it by eye (how else could they have?)
Again, not to make light of it, but sometime after it happened I (like a lot of other people I’m sure) tried doing it on MS Flight Sim. It includes NYC (they have since taken TWC out) and either a 757 or 767. It’s not easy. Big jets manuver like barges and going 500+ mph even TWC comes up pretty fast.
I feel bad saying that, because I don’t want to be seen as showing any admiration for the murderous, inhuman, cowardly (Bill Mahr was wrong) scumbags who did it…
Keep in mind, Beastal, that is wasn’t like aiming a gun and firing a bullet - the murderous scum (apologies to pond life for the comparison) were able to make small corrections in the trajectory up until the moment of impact. Yes, being off X amount at Y distance can result in a miss, but positioning the airplane precisely in space and time is something all pilots work towards. Keep in mind, too, that these [expletive deleted] no doubt practiced this manuver to one degree or another, with tools such a MS Flight Simulator, so that when they real deal was in motion they were much more likely to succeed. Even so, one of the airplanes had to make a sizable course correction in the last few seconds (hence the OP).
I think it is possible to admit that, yes, the tactics employed were brilliant from a military strategy viewpoint, but also to NOT condone in any way their actual use in the real world.
The account of the Pacific Southwest Airlines flight 1771 crash says:
If everyone aboard the plane died, and no part of the crash was larger than a square foot,
I smell journalistic embellishment.
Dunno, but here’s some more info .
Apparently, the flight recorder survived.