The 9/11 Forum

Ian wrote:

David B. Benson wrote:DavidSChandler --- Probably better to choose a more neutral descriptive term than 'explosions'. The term 'puffs' has been used on another thread here, the one devoted to the topic of these puffs occuring below the collapse front.

To the degree that "puffs" is an adequate adjective to describe these events, you have to stand in awe at the assumption that "explosions" somehow is more dubious a description. To me, "puffs" is what somebody does on a cigarette. Explosions don't have to come from "bombs".

Maybe we can compromise on the word "sneezes"?

David C writes:

I haven't heard any explanations from the official narrative side of the spectrum that would account for these explosions of vast amount of material at high speed simultaneously on multiple floors many floors below the collapse zone racing down the building to more or less keep pace with at least medium-density material (whatever chunk I'm tracking...big enough to be consistently visible on this scale) falling through air nearby.

I agree that the corner ejections both on the NW corner and SW corner are odd.

There are a few things in your presentation which may not be accurate.

1) The falling object you chose is most probably a piece of aluminum cladding. Both core and perimeter columns are about 38 feet long, Aluminum cladding will be about 13 feet long on average. Around the piece you chose you can see many pieces that look similar.

If you punch the numbers into a basic physics program then why not also plot the downward acceleration of the falling piece? Distance can be scaled using the building width.

I wonder what the results would be if vertical distance, velocity and acceleration were plotted for the falling object alone, or for the lowest ejections seen coming from near the SW corner alone? Would they tell us that the falling object was behaving as if it was heavy and in freefall?

Unless you can be sure the object you chose is a good example of a heavy object (like a column) in freefall, you cannot gain useful info by comparing it to the movement of the ejections.

2) I also think the BBC video clip is interesting. But from that angle you cannot say whether the ejected material you see is coming out of the west face in general or from the west face very close to the SW corner. What this video can tell you is that the collapse front along the SW corner is leading the NW corner collapse front by a good 15 to 20 stories.

You can clearly see this fact in this video clip. The flooring and perimeter is being destroyed along the SW corner much sooner than along the NW corner. For me, this fact puts the lie to "piston-like pressure build up" necessary to explain ejections seen far below the collapse front.

It puts the lie to many things. There are people who claim a thing called "crush-up, crush-down" took place, or a "pile-driver" smashed the bottom of the building to pieces. And yet you can clearly see the SW corner being destroyed much sooner than the NW corner by about 20 stories.

In your presentation you make the claim that the west side ejections seen are leading the collapse front. If we note that the SW corner collapse front is clearly leading the NW corner collapse front, then the claim ceases to have meaning. These ejections are not below the collapse front, they ARE the collapse front (along the SW corner).


Because of the 2 objections listed I cannot be confident that the conclusions you draw are correct.


It would be interesting to see the graph of the points you plot for the ejection front in terms of velocity and acceleration. That would tell us something much more solid than comparing the 2 plotted objects.

WTC 1. Same as the video that David C uses.

DavidSChandler wrote:I originally did a crude estimate of the ejection velocity of a chunk I could trace on a television screen and estimated horizontal ejections of over 60 mi/hr. When I realized I could import the videos into Physics Toolkit I came up with 72 mi/hr.

Did you compare to a theoretical value for air expulsion? I get 80 mph for the first collapsing floor.

DavidSChandler wrote:What I am trying to do is to make the point that the demolition wave is just that: a propagation of a series of explosions that move down the face of the building pretty well keeping pace with the material around it. You don't need pinpoint accuracy measurements to observe this. True, as a measurement it is a bit sloppy, but measuring the locations of dust clouds is an approximate enterprise.

If you read the opening post you will see that you choice of debris supports your thesis, but that two other obvious choices do not. The collapse front is not keeping pace with the heavy debris. It seems to me your primary thesis is invalidated.

DavidSChandler wrote:The real meat of what I have to say is in the first part of the video. Here is a chain of explosions occurring far below the actual level of collapse of the building...If these are not planted explosives, what are they?

They are evidence of a non-symmetrical collapse!

Your dubious "real meat" is not supported by either evidence or analysis.
Can you explain how explosions are not heard on video tapes of the collapses with sound? You may want to check out this thread before replying.

Hambone wrote:

DavidSChandler wrote:I originally did a crude estimate of the ejection velocity of a chunk I could trace on a television screen and estimated horizontal ejections of over 60 mi/hr. When I realized I could import the videos into Physics Toolkit I came up with 72 mi/hr.

Did you compare to a theoretical value for air expulsion? I get 80 mph for the first collapsing floor.

Hambone, could you provide that calculation, I have some things to add

1) you say it is the air that goes with 80 mph, here we are dealing with heavy objects, the air should provide that force then on the objects.
2) do you realize that your air theory doesn't really work for a tilting top section
3) do you realize that a large object is already ejected from the south tower before the top section reaches the next floor.
4) did you know that there are enough testimonies of huge explosions even in the beginning of the collapse
5) do you know that with simple video analysis the rumbling sound starts before the visible motion.

einsteen wrote:

Hambone wrote:

DavidSChandler wrote:I originally did a crude estimate of the ejection velocity of a chunk I could trace on a television screen and estimated horizontal ejections of over 60 mi/hr. When I realized I could import the videos into Physics Toolkit I came up with 72 mi/hr.

Did you compare to a theoretical value for air expulsion? I get 80 mph for the first collapsing floor.

Hambone, could you provide that calculation, I have some things to add

1) you say it is the air that goes with 80 mph, here we are dealing with heavy objects, the air should provide that force then on the objects.
2) do you realize that your air theory doesn't really work for a tilting top section
3) do you realize that a large object is already ejected from the south tower before the top section reaches the next floor.
4) did you know that there are enough testimonies of huge explosions even in the beginning of the collapse
5) do you know that with simple video analysis the rumbling sound starts before the visible motion.

It would be better if you calculate it yourself independently, then we can compare.

Regarding your points:

1) I'm not sure what you are getting at. Can you describe this a bit more?
2) What's my theory?
3) How was the large object ejected, air pressure or mechanically?
4) The sound recordings of the collapses have no apparent explosions especially when compared with actual CD's.
5) Please post a link to the video in question.

This photo is pretty amazing and is applicable to this thread.



The heavy object to which I was referring earlier has already fallen out of view. Let's temporarily ignore that piece and focus only on the two large interconnected pieces visible, one falling from the NE corner and one (to the right) from the west perimeter (I believe the collapse initiation zone, floor 92 to 98, I'll try to prove that in another thread).

Perhaps, if we ignore the piece I mentioned before, we can use these two obviously heavy objects as a reference of what freefall actually means.

We can note that perhaps David C is not completely wrong in his accessment of the rapid speed of the failure progression of the southeast corner. The SW corner ejection propagation is visible in this photo and is keeping up rather well with the large interconnected perimeter section falling from the collapse initiation zone.

More comment to come.

Yes, but it is the SW corner to which I am referring. This is also the front that David C is comparing the falling objects to in his presentation in the OP.

The SW corner is on the far right in this photo. The NW corner to which you are probably referring is closest to the viewer. The SW corner leads the NW corner by a substantial margin which seems to increase in time.

The best clip to see the comparison between the SW and NW corner collapse front ejections was posted before, reposted below.

http://www.youtube.com/watch?v=Xo7t3XQ2 ... re=related

This unique view captures the west face behind the falling and obscuring dust and you can clearly see that the SW corner ejections lead that of the NW corner by a good 10 to 20 floors.

Major_Tom wrote:Yes, but it is the SW corner to which I am referring. This is also the front that David C is comparing the falling objects to in his presentation in the OP.

The SW corner is on the far right in this photo. The NW corner to which you are probably referring is closest to the viewer. The SW corner leads the NW corner by a substantial margin which seems to increase in time.

The best clip to see the comparison between the SW and NW corner collapse front ejections was posted before, reposted below.

http://www.youtube.com/watch?v=Xo7t3XQ2 ... re=related

This unique view captures the west face behind the falling and obscuring dust and you can clearly see that the SW corner ejections lead that of the NW corner by a good 10 to 20 floors.

What speed and how far ahead was the collapse front (SW corner) moving at when the heavy pieces in question started falling?

I already know that the corner piece from the NE corner is from floors 92 to 97. It detached from the building in the first moments of collapse iniitiation with remarkable ease and doesn't appear buckled or significantly bent. I suspect this is from the miraculous properties of the "soot lines" discussed in another thread.

So in answer to you question

What speed and how far ahead was the collapse front (SW corner) moving at when the heavy pieces in question started falling?

they both start from the same place (floors 92 to 97) at the same time (the earliest moments of collapse initiation).

The very large interconnected perimeter piece leading the fall from the west perimeter (except for the 2 column piece I discussed earlier) and from which the first obscuring smoke/dust trails came on that side is, I believe, also from the collapse initiation zone, floors 92 to 97 and also detached from the building with remarkable ease without significant deformities.

In fact, there are 2 other very large interconnected perimeter sections falling which have not yet been mentioned: One falling from the north face and slightly trailing the first two, and yet another from the southern part of the east face.

Each of these 4 very large perimeter sections are very similar in that:

1) All 4 seem to detach from the building with remarkable ease at about the same time.

2) All 4 seem to come from between floors 92 to 97, the collapse initiation zone.

3) All 4, though seen from a distance, do not seem to be buckled or deformed in any noticable way. They all just kind of "fell off" the building at the earliest moments of collapse initiation.

4) They all seem to be about 5 or 6 stories tall.

5) Every one of them has a large amount of smoke (or dust or gypsum or pulverized concrete) trailing from them and, as they lead the fall, each one serves as the first pieces to obscure the tower from view. Whatever each of these sections are trailing seems to stream from the backside of the sections at a seemingly constant rate, trailing just as much "dust" later in the fall as it approaches the ground as it does in the early moments of visibility.


So if we ignore the 2 column section of which I first spoke, these 4 large sections, detaching from the collapse initiation zones at the first moments, and being so large that they are visible from photos taken from far away, can serve as a natural reference of what freefall means in a practical sense.

Hambone, I believe you use one as a reference object in your OP, marked in orange(?) (this would be the west perimeter section).

You've already seen photos and video of 2 of these sections. I'll discuss the other 2 when I have a bit more time.

For those who are curious, they can all be seen in the following photo album which focuses only on WTC 1 fires and collapse.

http://www.sharpprintinginc.com/911/ind ... on=140:140

or the index version of this album below

http://www.sharpprintinginc.com/911_old ... _and_demo/

Please ignore the caption. This photo shows the west perimeter section clearly. The north perimeter section is just becoming visible. It is the thing from which the "dust' is trailing leading the fall on the north side. It is just emerging from the dust at this point. The NE corner perimeter piece is already obscured by the other building. You can only see the dust it has left behind.

Good photo of both the 2 column section leading everything in the fall and the NE corner section (on the left).

The piece falling from the north perimeter is hard to see. It doesn't become distinguishable from the dust until after it is behind WTC 7. Here is a glimpse of it.



You can also clearly see the west perimeter section and a bit of the NE corner section behind WTC 7. This photo allows you to see the positional relationship between the three sections.