Oh, you mean the part that says
Is that the "data" you didn't see, or are you asking for another scientific analysis using simulation models?
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Oh, you mean the part that says
Is that the "data" you didn't see, or are you asking for another scientific analysis using simulation models?
Then why aren't we questioning the whole premise that the towers collapsed from the heat when there were witness reports of survivors and fire fighters which state that there was no inferno? I'm more likely to trust those than "science-y"-looking assumptions and simulations from people who weren't on site during the incident.
LunarRay
Diamond Member
- Mar 2, 2003
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You scienc-y types give me the woolies.. heeheheh
Could you tell me where the screw up occurred regarding the folks who built the buildings saying they could withstand a 707 hit? I've seen the numbers regarding the expected hit dynamics of a 707 at cruise vs the heavier 767 at maniac speed... it is not that great at all. So where would I start to pin the tail - on which donkey?
Perhaps you could tell me if you disagree with this below to any material degree.
'The twin towers were designed to withstand a collision with a Boeing 707.
The maximum takeoff weight for a Boeing 707-320B is 336,000 pounds.
The maximum takeoff weight for a Boeing 767-200ER is 395,000 pounds.
The wingspan of a Boeing 707 is 146 feet.
The wingspan of a Boeing 767 is 156 feet.
The length of a Boeing 707 is 153 feet.
The length of a Boeing 767 is 159 feet.
The Boeing 707 could carry 23,000 gallons of fuel.
The Boeing 767 could carry 23,980 gallons of fuel.
The cruise speed of a Boeing 707 is 607 mph = 890 ft/s,
The cruise speed of a Boeing 767 is 530 mph = 777 ft/s.
So, the Boeing 707 and 767 are very similar aircraft, with the main differences being that the 767 is slightly heavier and the 707 is faster.
In designing the towers to withstand the impact of a Boeing 707, the designers would have assumed that the aircraft was operated normally. So they would have assumed that the aircraft was traveling at its cruise speed and not at the break neck speed of some kamikaze. With this in mind, we can calculate the energy that the plane would impart to the towers in any accidental collision.
The kinetic energy released by the impact of a Boeing 707 at cruise speed is
= 0.5 x 336,000 x (890)^2/32.174
= 4.136 billion ft lbs force (5,607,720 Kilojoules).
The kinetic energy released by the impact of a Boeing 767 at cruise speed is
= 0.5 x 395,000 x (777)^2/32.174
= 3.706 billion ft lbs force (5,024,650 Kilojoules).
From this, we see that under normal flying conditions, a Boeing 707 would smash into the WTC with about 10 percent more energy than would the slightly heavier Boeing 767. That is, under normal flying conditions, a Boeing 707 would do more damage than a Boeing 767.
In conclusion we can say that if the towers were designed to survive the impact of a Boeing 707, then they were necessarily designed to survive the impact of a Boeing 767.
So what can be said about the actual impacts?
The speed of impact of AA Flight 11 was 470 mph = 689 ft/s.
The speed of impact of UA Flight 175 was 590 mph = 865 ft/s.
The kinetic energy released by the impact of AA Flight 11 was
= 0.5 x 395,000 x (689)^2/32.174
= 2.914 billion ft lbs force (3,950,950 Kilojoules).
This is well within limits that the towers were built to survive. So why did the North tower fall?
The kinetic energy released by the impact of UA Flight 175 was
= 0.5 x 395,000 x (865)^2/32.174
= 4.593 billion ft lbs force (6,227,270 Kilojoules).
This is within 10 percent of the energy released by the impact of a Boeing 707 at cruise speed. So, it is also a surprise that the 767 impact caused the South tower to fall.'
LunarRay
Diamond Member
- Mar 2, 2003
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For 5 minutes kindly lend me your expertise.
I did read that but can't tell if it is faulty.
Do you find fault with it?
I'm simply looking for the first time at this stuff on design criteria.. I've to start somewhere and I think the criteria they state is either true or not.
I really, really would appreciate your opinion on the numbers.
BTW, it is a quote... the numbers that is.
Sorry, I mean could you help with the data after the plane weights and capacity and that.. I've done that.
Cogman
Lifer
- Sep 19, 2000
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... He is calculating kinetic energy wrong. He divides by the gravitational constant when he shouldn't. In fact, I really don't know why he would even consider dividing by the gravitational constant. In fact, he even refers to the energy wrong. Energy != Force. They are two different concepts.
Also, the 707 quote is taken from pre-1990 simulation of a plane crashing into the building (It may have even been in the 70's that the calculation was done, I'm not sure. The first reference I found to a 707 was in a 1993 newspaper article talking about the '93 bombings). Surprise, Surprise, an early computer simulation/model was wrong.
So, should we cling this "Experts" opinion? The guy doesn't even know basic kinematics.
LunarRay
Diamond Member
- Mar 2, 2003
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Ok.. thanks for your time!
For what it's worth this is what I was starting to use from Wiki
720 (707-020)
Cockpit crew Three
Passengers 140 110 (2 class)
179 (1 class) 147
Length 136 ft 2 in (41.25 m)
Wingspan 130 ft 10 in (39.90 m)
Tail height 41 ft 7 in (12.65 m) )
Maximum Takeoff Weight (MTOW) 222,000 lb (100,800 kg)
Empty weight 103,145 lb (46,785 kg)
Takeoff run at MTOW 8,300 ft (2,515 m)
Fuel Capacity 16,060 US gal (60,900 l)
Landing run 5,750 ft (1,740 m)
Operating range (Max Payload) 3,680 nmi (6,820 km)
Range at MTOW (max fuel) 3800 nmi (7,040 km)
Cruising speed 540 kn (1000 km/h)
Fuselage width 12 ft 4 in (3.76 m)
Powerplants (4 x) Pratt & Whitney JT3C-7:12,000 lbf (53.3 kN)
The above is the only one I think they'd have considered.
There is a conversion from Kn to Mph... but that is no biggie... I was simply using the F=MA where mass was 103,145 plus 10,000 gal at 8lb a gal plus passengers and crew at 170 lbs per and a 10,000 lbs for luggage and diapers and any other stuff. I simply didn't get too close to those he listed so... my dilema.
LunarRay
Diamond Member
- Mar 2, 2003
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No, I didn't know that. I find most of the entries of this nature are from the manufacturer. Boeing (when I looked) didn't have the pre '70 vintage so I used the oldest wiki had.
But, I don't rely on Wiki for what I have my own reference capabilty for. I use it for other stuff that is of no consequence in the general sense.
In other words, if I were teaching Law I'd not expect a reference to a case from Wiki but would accept one on say Federalist papers...
Edit: Oh wait.. you're the guy from last night... hehehehe Am I suppose to say something wise back at you... hehehehe
Björkman's "axiom" is plainly contradicted by the numerous historical progressive collapse incidents. Just look at the 24-story Skyline Plaza collapse: a localized failure in floor 22 ("Part C") resulted in the progressive, catastrophic failure of the entire underlying structure ("Part A"). "Axiom" disproven.
And as Cogman already noted, Björkman is completely batshit insane.
it looks as though the concrete had not hardened with the skyline plaza collapse. i dont think that would be a good example for wtc 1,2, or 7 since the concrete was hard.
Cause
"Fairfax County hired Professor Ingvar Schoushoe of the University of Illinois, a concrete specialist, to investigate the cause of the collapse. He determined that the collapse occurred because of the premature removal of shoring from beneath newly poured floors.[10][11]
George Taylor, a workman for Northwest Sheet Metal, Inc., claimed that workmen were pulling concrete supports "out too damn fast. They're trying to hustle the job too damn fast."[2]
http://en.wikipedia.org/wiki/S...s_collapse#cite_note-9
so the link you posted only gave 2 examples of progressive collapses. the ronan point, which was interesting, and the murrah federal building. if anyone remembers, the murrah building got blasted by a big ass bomb!!
regarding bjorkman, looks like a good smear campaign.
lets focus on wtc 7. i think thats what the op was asking about. have you read the fema bpat report app c yet?
also concerning the ronan point-
http://matdl.org/failurecases/...ases/Ronan%20Point.htm
"Ronan Point was razed after just eighteen years of service. However, the building was not demolished in the traditional fashion. Webb suspected poor workmanship, and therefore insisted that Ronan Point be dismantled floor by floor so that the joints could be studied. The site was an ?open site? for anyone interested. It was verified that compromises in workmanship were present.
A shocked Webb commented, ?I knew we were going to find bad workmanship ? what surprised me was the sheer scale of it. Not a single joint was correct. Fixing straps were unattached: leveling nuts were not wound down, causing a significant loading to be transmitted via the bolts: panels were placed on bolts instead of mortar. But the biggest shock of all was the crucial H-2 load-bearing joints between floor and wall panels. Some of the joints had less than fifty percent of the mortar specified.? (Wearne, 2000)."
also check out the picture of ronan point from the link above. its not like the whole damn building fell like wtc 1, 2, and 7.
http://matdl.org/failurecases/...ases/Ronan%20Point.htm
"Ronan Point was razed after just eighteen years of service. However, the building was not demolished in the traditional fashion. Webb suspected poor workmanship, and therefore insisted that Ronan Point be dismantled floor by floor so that the joints could be studied. The site was an ?open site? for anyone interested. It was verified that compromises in workmanship were present.
A shocked Webb commented, ?I knew we were going to find bad workmanship ? what surprised me was the sheer scale of it. Not a single joint was correct. Fixing straps were unattached: leveling nuts were not wound down, causing a significant loading to be transmitted via the bolts: panels were placed on bolts instead of mortar. But the biggest shock of all was the crucial H-2 load-bearing joints between floor and wall panels. Some of the joints had less than fifty percent of the mortar specified.? (Wearne, 2000)."
also check out the picture of ronan point from the link above. its not like the whole damn building fell like wtc 1, 2, and 7.
The more I think about it, even if I dropped 50 lbs of ultra-dense material (say - plutonium), the twoophers head is a) protected by customized twuufer tin foil b) has a special unique density which does not allow logic in, and therefore is protected from injury c) filled with rocks anyhow, so any damage would just further pulverize the rocks
- Mar 25, 2000
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This the fact that the second tower hit was the first to come down isn't dubious in itself, as the second tower was hit much lower, and hence the weakened portion of the structure was under far more weight. However, that either came down in their entirety, as they did, is not explainable while holding to the official story.
That argument is based in an absurdly false dichotomy; suggesting that the towers had to be brought down by either the force of gravity or that of explosives, as if the use of explosives would suspend the effects of gravity.
Because the melted steel can't be explained while still maintaining the official story, hence the reason NIST not only left the melted out of their report, but outright refused to acknowledge its existance.
- Mar 25, 2000
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Number1
Diamond Member
- Feb 24, 2006
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Look, stop using your dyslexia as a crutch and switch to a browser with a built in spell checker like firefox. The spelling mistakes get underlined in red automatically.
Simple yet effective.
It's just too bad there are no programs out there that could help you differentiate reality from made up stuff.
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