WI: Flight 175 doesn't bank left at the last second?

[robobox]

I've tried looking around for a somewhat definite answer to a question that is suprisingly not often asked: what if the hijackers didn't bank the plane to the left at the last moment before impact?

I think at least the left wing would clip into the tower, but I'm not sure what would happen after that.

 

[mattep74]

The 10 to 20 people above the point of impact that escaped by the undamaged stairwell would have died

 

[aaronupright]

767 fuel tanks are mostly in the wing. So, little difference.

 

[DougM]

I never really studied the actual impact just the results so can you explain how much of an impact you expect this to be? I take it you exoect the Fuselage to miss as well as one wing? But the other wing to hit? If so how much of the other wing?

The buildngs were designed to take an Airplane inoact and the resulting fire. It was just that the modern aircraft we beyond the design limits as in the Mid 60s you dint have the same size aircraft.

Also without the Fuselage impact you would have less “shotgun effect” sandblasting the firing retardant off the structure and what you do have of this effect will be more concentrated on the outer edge of the structure not the inner area. And this is calked fireproofing is less important on the out structure as this structure was “cooled” (sort of) by the outside air brought in through the shattered windows. This was somewhat planed for in the original design by the way.
So depending on how much hits the building you could have the Tower stand.
As for escaping via a stairwell, without a more direct impact you will have other stairwells remain intact.

The real question is… if you get enough fir concentrated on one side of the structure and the exterior air flow is not sufficiant to safe the structual integrity if the columns then the building could fail on one side resulting in the building tipping as it colapses vs the so calked implosion we got in original timeline.

For those that may be less familiar with the way the buildings came down or were built. The towers were effectively build with and inner core and an outer ring of steel columns, All steel was coated with a “fire proof” treatment that sort of looks like spray foam. But this stuff would have been “sand blasted” off from the shotgun effect of the aircraft impact, The Towers were designed at a time when the 707 was the largest aurcraft likly to impact the towers and this WAS considered as the designers were well aware of the medium bomber that had hit the Empire State Building after WW2.
The problem with an Aircraft impact is NOT the impact but the resulting fire, Steel takes a LOT of heat to ”melt” but not that much to lose a noticeable percentage if its strength, And while most fire wont be hot enough a jet fuel fire concentrated in the center if the building were outside air cant cool the structure is hit enough to weaken the steel. Picture how the center of a Bonfire is much hotter then the outer edges, The center contains the heat.
When designing the towers one if the concerns was that in a fire the building could tip over creating a domino effect of building in Manhattan that could be catastrophic, I personally always thought this was what the terrorists hoped would happen. In and effort to avoid this tipping and domino effect the designers designed the building in such a way that the center was more likely to experience higher heat as the out rung if columns was located much closer to the glass. And the glass would fail in a fire And the combination of being away from the center and near the windiws that were letting in the air that was being sucked in to feed the fire. This air flow if cooler air being sucked in would result in the outer columns retaining a but more strength a but lionger then the inner core. Thus the building should collapse from the inside and the outer ring if structure should contain and guide the fall in the so called “implosion”. This is more or less what happened. If you look at the videos at kleast one of them shows the antena on the roof stating to fall straight down. This indicates that the center structure has failed at some point. and as the center fell it pulled the outside in with it ”imploding” vs tipping over. Personally i dont think that the designers get enough credit. If mot for there hard work the tragedy of 9-11 could have bern orders or magnitude worse in terms of both property damage and lose of life.
BTW I had lunch with an Architect that worked on the towers less then a week after 9-11 and he drew all this out for me at that point. He did nit do much on the towers but his good friend was one of the leads on the project and they talked about it often in the office or at lunch or what have you and his friend ran ideas past him. So i am not just pulling this info out if thin air, I am intentionally being vague about what positions they had and who these gentlemen were as i never asked permission to repeat what they said to me so i don't want to put words in there mouths.

So depending on HOW much fuel is involved we could see a LOT less damage (odds are if only part of one wing impacts. As the lesser fuel source combined with less lost of fire retardant from the impact and the fire being located closer to the exterior of the building would combine to create a “survivable” fire. The variables however are extreme. If we get more fire and no no fire fighters then we could see a colapse still and that could tip the building resulting in an increased casulties in the surrounding area. Odds are less likly for this to happen but structurally sperking it is possible, But we would need to know a lot of variables. And even then i am not familiar enough with the calculations to determe how much fuel located at a guven point would result in a lose of structural integrity in enough columns to cause a colapse,

TLDR: The builders were designed for an aircraft hit but a smaller aircraft then what hit them. So a lesser hit concentrating the fire closer to the edge if the building has good odds of the building surviving, But we need more info on the impact as if enough fuel still hits then the building could tip vs implode creating a bigger nightmare the irl,

 

[DougM]

Just looked it up we are talking 707- 14000 gal of fuel vs a 767 - 24000 gal. Best estimate i have seen has a center tsnk of about 7000-8000 leaving wing tanks if about 8000-8500 each, If only one wing hits we are looking at probably 7000 gal. This is below the building design factir abd thus it is very possible that this tower would stand,

 

[Catsmate]

The buildngs were designed to take an Airplane inoact and the resulting fire. It was just that the modern aircraft we beyond the design limits as in the Mid 60s you dint have the same size aircraft.

No they were not, this is an utter nonsense.

When they were constructed Robertson made some 'back of an envelope' calculations that suggested the towers could withstand an aircraft impact, basing this on the concept of a smaller aircraft at landing speed that was "lost in fog". It did not factor in the effects of fuel and fire leading to weakening of the steel structure.

 

[DougM]

And you worked with the designers so you know this? I normally dont tell people on this forum that they are fufill it but YOU are 100% wrong. And while i was not there when they were designed. (not having been born yet). I have NO reason to belive that the poeple i knew who WERE there when they were designed and worked on the design would bother to lie to me about this,. I have actually met and talked with people that designed those structures have you?

And do you think a fire never entered the minds of the designers? Really? Or that fire weakening steel is unknown? What do you think engineers and architects do when they design buildings? Just say…. “oh that looks good enough”….

This type of comment is why this forum is becoming a joke. Anyone that knows something has to put up with this kind of bull comment.

Date: The Wednesday after 9-11. The location a Small Restaurant in a suburb of Detroit Mich. The time. was an Early(ish lunch) Participants were a Young Designer and and Old Semi retire Architect. They had encountered each other earlier in the day when the Architect had stopped by the Architectural Engineer company the designer worked at to consult on a problem. The older Man invited the designer to lunch to talk.
Durring lunch the Architect pulled op a pad of psper and a pen an drawer out the structure of the building. and started a combination of reminiscing about the time when he was young and his friend and mentor was one of the leading people on the design of the towers.
He schethed out one idea they had for the structure as well as the final design and explained some of the logic behind the one they went with. He explained that in a fire (airplane induced or not) the concern for steel failure. And that the building was rated for a fire if X duration and Y intensity. Which could result from sources such as major electrical, gas or Aircraft as the case may be, He also pointed out that the fireproofing was in many ways deemed to be worthless as it was known it could physically fail in many instances as it could be knocked off. At the time this conversation was both a chance to share knowledge with the younger generation and seamed to be the Architect re-examineing things as if he was wondering if he and the team could have done something differently. I imagine that he was feeling a bit guilty that a building that he helped design had failed and cost thousands of peoples lives, At the same time ge was proud that the building perform as intended and fell in on itself vs over on other buildings.

Ok I have. told you were i got my info…. Lets here where you got the info showing that me and my source are wrong…

I should truly know better then bothering to discuss topics i have knowledge of on this forum.
This has all the hallmarks of turning into another farce like the conversation about the Carbine use in Korea. Where the internet experts all say it sucked based on waching each others posts and comments despite the testimony of Korean vets who took them on patrol over Garands abd dispite tests that show a carbine bullet has at 200 yards the same energy as a 357 magnum has at the mouth of the barrel. The rumor is just more prevekent and seams to carry more weight then the eye witness account of a couple of people that shot people with them….

To the OP of this topic. Sorry for trying to have a practicle discusion on your topic. I will now leave you to continue this conversation with the “experts” that know more then I or members of the actual design team.

Note to self. Dont bother to discuss things i know on this forum.

 

[YYJ]

I have read quite a bit about the Twin Towers collapse including the NIST report. No one seems to be able to produce the claimed design specs that account for an airplane impact. It seems to be apocryphal. If you have this document, not reference to the document, but the actual document, please link.

 

[YYJ]

The sequence of collapse found by the NIST was:
1)the steel floor trusses on the affected floors were heated by the contents fire and expanded.
2)the (surviving) outer columns were still rigid in the early fire, so the only way for the expanding trusses to go was to kink, and they bent downward.
3) as the fire moved up through the building, floors above the point of impact suffered the same effects.
4) the outer columns and the floor trusses functioned as a single structural unit, so as multiple stories of floor trusses sagged, the outer columns were pulled inward.
5) eventually the outer columns were pulled out of plumb enough that gravity overcame the structure and one floor fell, which fell onto an already weakened floor below and proceeded into a rapid progressive collapse.
6) the collapse was delayed by a massive “hat truss” at the top of the building transferring load from weakened columns to stronger columns.
7) some of the both the outer and inner columns were cut by the planes on each building, so the structure was weakened at the moment of impact.
8) the impact severed sprinkler mains and stripped fire protection from the steel trusses as mentioned above.

If the plane struck just one edge of the building, the OP seems to be asking, would the building in question have fallen like a tree from the point of impact?

Perhaps, if something really solid like an engine was lined up perfectly down the line of columns.

But I think the effect of a glancing blow would be that less kinetic energy would be delivered to the structure. The planes had some solid parts that OTL passed all the way through the structure and out the other side. But most of the mass of the plane was small aluminum components, luggage, passengers, and fuel. This material, would have broken up into small pieces, but still, like an ocean wave hitting an object, would have delivered its full kinetic energy to the structure. This broke some columns and stripped out the drywall partitions, suspended ceilings, and the sprayed-on fire protection on the steel floor trusses on most of 4 stories. The fuel explosion way have done some explosive damage, but mostly deflagrated and lit the contents on fire.

The key damage, in my understanding, was cutting the sprinkler mains, removing the fire protection, and lighting the contents so vigorously on fire. Any plane impact that did that IMO would eventually result in a total collapse. A plane impact that failed to do that would probably leave a standing damaged building that would need to be torn down later.

There are all kinds of scenarios that might have left the buildings standing longer, and therefore would have allowed more people to escape.