The World Trade Center towers were designed to withstand the impact of a Boeing 707, hence (by default) they were designed to withstand the impact of a Boeing 767.
THE WTC WAS DESIGNED TO SURVIVE THE IMPACT OF A BOEING 767.
Fact. 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 can carry 23,000 gallons of fuel.
The Boeing 767 can 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.
Information on the Boeing 707
www.boeing.com/commercial/707family/product.html
Information on the Boeing 767
www.boeing.com/commercial/767family/pf/pf_200prod.html
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.
From
www.nerdcities.com/guardian/WTC/wtc-demolition.htm The World Trade Center Demolition. 740 KB
or from
www.thepowerhour.com/911-nerdcities/World%20Trade%20Center%20Demolition.htm 740 KB
ALSO, there is the following from the page
www.nerdcities.com/guardian/WTC/WTC_ch1.htm 850 KB
This is a critique of Chapter One of the FEMA report. The FEMA report is enclosed within <<-- -->>
<<--The WTC towers were the first structures outside of the military and the nuclear industries whose design considered the impact of a jet airliner, the Boeing 707. It was assumed in the 1960s design analysis for the WTC towers that an aircraft, lost in fog and seeking to land at a nearby airport, like the B-25 Mitchell bomber that struck the Empire State Building on July 28, 1945, might strike a WTC tower while low on fuel and at landing speeds.-->>
That the WTC was designed only to withstand a collision with a Boeing 707 that was seeking to land at a nearby airport, and therefore low on fuel, is an obvious lie. Why is it an obvious lie? Well, because if you take into consideration planes that are landing at an airport, then you must consider planes that are taking off, and such planes are fully laden with fuel.
<<--However, in the September 11 events, the Boeing 767-200ER aircraft that hit both towers were considerably larger-->>
(Not true. Somewhat larger, would be more accurate.)
<<--with significantly higher weight, or mass-->>
(Also, not true. Using the weights quoted by this article, in fact, in the very next sentence, the Boeing 707 considered by the designers, weighed 263,000 pounds and the Boeing 767s that hit the towers weighed about 274,000 pounds. This is a difference of 4%. Yes, four percent. Nobody thinks 4 percent is a "significantly higher weight". Incidently, the maximum takeoff weight for a Boeing 707 is 336,000 pounds. The maximum takeoff weight for a Boeing 767-200ER is 395,000 pounds.)
<<--and traveling at substantially higher speeds. The Boeing 707 that was considered in the design of the towers was estimated to have a gross weight of 263,000 pounds and a flight speed of 180 mph as it approached an airport; the Boeing 767-200ER aircraft that were used to attack the towers had an estimated gross weight of 274,000 pounds and flight speeds of 470 to 590 mph upon impact.-->>
What evidence do we have that the designers only considered impacts by planes that were flying close to stall speed (the stall speed, is the speed below which the aircraft falls out of the sky). Apparently, we only have this articles word for it. And we already know that they are quite willing to lie and exaggerate the facts.
Another reason that we know that the authors are just making up "facts" here, is that the WTC was designed to handle extreme wind loading and would thus survive the impact of a Boeing 707 (even one that was traveling at full speed) without adding any extra features to the design of the building (above those already necessary to handle the wind loading). All that the designers would have to consider, is effect of a jet fuel fire from a fully fueled jet that crashed into one of the towers shortly after taking off from one of the local airports.
Clearly, for an aircraft like the Boeing 707 to accidently impact one of the towers, the pilots must have lost control. Most aircraft crash during take off or landing, however, there is also the possibility of mechanical failure at altitude, that causes the pilots to descend without full control. In this scenario the plane would impact the tower at high speed. Who is to say that the designers did not consider this possibility?
To see how willing to "stretch the truth" the authors of this article are, compare Figure 1-10 to the original (that can be found by clicking here). Notice that they have "accidently" quoted the length, height and wingspan of one of the early 707's (possibly the Boeing 707-120) and the weight, fuel capacity and speed of the more common Boeing 707-320B (the aircraft that most people associate with the name, Boeing 707). I have edited the graphic so that it is now presents a more accurate picture.
<<--Including aircraft impact as a design load requires selecting a design aircraft, as well as its speed, weight, fuel, and angle and elevation of impact. Figure 1-10 compares the design characteristics of several large aircraft that were in use or being planned for use during the life of the WTC towers. The maximum takeoff weight, fuel capacity, and cruise speed shown for each class of aircraft are presented for comparison of relative sizes and speeds.-->>
So summarizing the data from above, we have that:
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 can carry 23,000 gallons of fuel.
The Boeing 767 can 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.
Information on the Boeing 707
www.boeing.com/commercial/707family/product.html
Information on the Boeing 767
www.boeing.com/commercial/767family/pf/pf_200prod.html
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.
Since the Boeing 707 had a higher thrust to weight ratio, it would be traveling faster on take-off and on landing.
The thrust to weight ratio for a Boeing 707 is 4 x 18,000/336,000 = 0.214286.
The thrust to weight ratio for a Boeing 767 is 2 x 31,500/395,000 = 0.159494.
Also, since the Boeing 707 would have started from a faster cruise speed, it would be traveling faster in a dive. So in all the likely variations of an accidental impact with the WTC, the Boeing 707 would be traveling faster. In terms of impact damage, this higher speed would more than compensate for the slightly lower weight of the Boeing 707.
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.
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TRY THESE FOR A LITTLE MORE TRUTH ABOUT 9-11.
www.nerdcities.com/guardian/WTC/wtc-demolition.htm The World Trade Center Demolition. 740 KB
www.nerdcities.com/guardian/WTC/south-tower.htm Evidence of Explosives In The South Tower Collapse.
www.nerdcities.com/guardian/WTC/WTC_ch1.htm Chapter One of the FEMA WTC collapse report (with comment). 850 KB
www.nerdcities.com/guardian/WTC/WTC_ch2.htm Chapter Two of the FEMA WTC collapse report (with comment). 1.9 MB
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www.nerdcities.com/guardian/SeptemberEleventh/arabs-not-to-blame.htm Arabs Not To Blame For 9-11.
nerdcities.com/guardian/SeptemberEleventh/ang-mission.htm The Treasonous Air National Guard's Mission And Vision Statements.
serendipity.magnet.ch/wtc.html The World Trade Center Demolition from serendipity.magnet.ch
serendipity.magnet.ch/wot/mslp_ii.htm McMichael's Analysis Of The World Trade Center Demolition.
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news.bbc.co.uk/hi/english/world/middle_east/newsid_1559000/1559151.stm Hijackers Still Alive From the BBC.
www.nerdcities.com/guardian Full list of articles from
www.nerdcities.com/guardian
For faster downloads you can find 3 of the above articles mirrored at
www.thepowerhour.com/911-nerdcities/nerdcites.htm
www.thepowerhour.com/911-nerdcities/World%20Trade%20Center%20Demolition.htm The World Trade Center Demolition. 740 KB
www.thepowerhour.com/911-nerdcities/Chapter%202%20-%20The%20WTC%20Report.htm Chapter Two of the FEMA WTC collapse report (with comment). 1.9 MB
www.thepowerhour.com/911-nerdcities/American%20Airlines%20Flight%2077.htm The Pentagon Crash Hoax. 1.4 MB