Jet engine sim for testing 9/11 planes

Originally posted by Pilgrum
With your extensive experience in law enforcement (and presumably the investigation/prosecution side of things), how often does the FBI release evidence before the investigation is complete?

Is the investagation still ongoing? I have not seen any information about new trails or any more on plane reconstuctions or other ongoing crime scene investigations.

What about FOIA request?

I'm very hopeful that the current 'space-beam' cases will eventually bring some more of the solid evidence out in the open.

Well the main thing is if the current cases proves that any of the defendents involved lied that would open things up for more cases.

I only read the first couple of pages so forgive me if this has been mentioned.

Ultima1,
I'm an ex USAF jet engine tech with flightline and testcell experience on large aircraft. Your reasoning was flawed in your original argument about thrust. First, airliners/large cargo type aircraft use high bypass turbofans, fighter type aircraft use low bypass turbofans usually with afterburner. These fighters only use AB when required for additional thrust for take-off or evasion or other urgent situations requiring faster response. High bypass = the fan produces most of the thrust = more fuel efficient. Low bypass = the core produces most of the thrust = more powerful for size = ideal for fighters. Aviation 101 teaches action-reaction. Thrust produced by the engine is the action. The aircraft moving forward is the reaction. In other words, the energy produced by the engine (thrust) in flight is propelling the aircraft forward therefore nothing behind the aircraft is affected as the spent energy disperses. On ground where the aircraft is stationary as in engine run-ups, the thrust is not propelling the aircraft so the energy works against what holds the aircraft. Inflight thrust exists but the engine exhaust has little effect behind the aircraft and disperses rapidly. If your reasoning was true, aircraft landing on carriers wouldn't be possible. As far as overtemp goes, Its hard to do in flight as the action of flying supplies cooler air to the fan which normally keeps the turbine section in check temperature wise unless there is something else wrong with the motor or it has been in overspeed for a time. I'm not sure what that is but was typically ~5 min on ground without the benefit of flight speed airflow into the motor. I seem to remember something mentioned about overspeed but can't recall the specifics, N1 or N2, duration, egt during the event. Incidently, I've been behind a C5 cargo plane with all 4 at Idle, it shook the truck a little but that's it(I wasn't driving).

[edit on 2-6-2008 by TheTraveler]

[edit on 2-6-2008 by TheTraveler]

Originally posted by ULTIMA1
Well the main thing is if the current cases proves that any of the defendents involved lied that would open things up for more cases.

Exactly

What's a ballpark figure for how long it will be before all litigation is complete and no avenues for legal challenges remain, making it reasonable to release all the evidence the FBI is holding - 20, 30 ,50 years or even longer?

Until that time is reached, they'd be doing themselves and the administration a disservice legally to release evidence prematurely.

We'll see bits and pieces of it as it becomes necessary to reveal it.

Originally posted by TheTraveler
Ultima1,
I'm an ex USAF jet engine tech with flightline and testcell experience on large aircraft. Your reasoning was flawed in your original argument about thrust.

So your stating everyone else is wrong when they state that JETWASH is main part of wake turbulence?

You are the only one thats right?

Originally posted by Pilgrum
What's a ballpark figure for how long it will be before all litigation is complete and no avenues for legal challenges remain, making it reasonable to release all the evidence the FBI is holding - 20, 30 ,50 years or even longer?.

Well if more people would file FOIA request and keep e-mailing companies maybe we could put some pressure on them to release evidence that should be releeased to the public.

reply to post by ULTIMA1


I don't know where you got your statement of everyone saying jet exhaust/wash makes up the majority of the wake turbulence. In fact, pretty much everyone other than you have been saying that it makes up the smaller portion of wake turbulence.

TheTraveler's assesment is entirely correct (using his action/reation energy explanation). The majority of it is the byproduct of the wings' lift and the fuselage cutting through the air.

Take this comparison: A 757-200 using RB211 engines produces 73,200 lbs of thrust total (36,600 per engine). A fully loaded 757-200 weighs 255,000 lbs. The wings would need to produce at least that much force in lift to keep the 757-200 flying.

Simple math. 255,000 lbs > 73,200 lbs
Thus the engine exhaust makes up the minority of the wake turbulence.

It's not whether or not TheTraveler's "the only one right", as you put it. He's just stating the facts of aerodynamics as it is.


As for the FOIA requests, the only way I can see it making a difference is if everyone in the US made a request. Because lets face it, (with all due respect) there are much more importatnt things to do in life for them (bills, school, jobs, kids, etc.). The majority of the population has already accepted the tragedy and decided to move on. I'm not saying it's bad to ask questions, just stating what's obviously true.

Right now, the people making the requests are a very small minority of the population and those FOIA requests can easily be funneled into the respective agency's "black hole" where they can be labeled as lost, on indefinite backlog, etc., etc..

[edit on 2-6-2008 by HLR53K]

reply to post by HLR53K


HLR....actually, 255,000 pounds would be a maximum, and would then qualify as 'Heavy' in ATC parlance.

AAL77 was far lighter....small payload, and almost an hour of fuel burned off....


The B757-300 is called 'Heavy'....as, of course is the B767 (all models).


[edit on 6/2/0808 by weedwhacker]

reply to post by weedwhacker


Ok, I stand corrected for not taking the fuel consumption into account. Lets go with your corrections.

The Boeing site says it can range from a low of 220,000 lbs to a maximum of 255,000 lbs. Lets take it even lower to compensate for the fuel consumption and make it 200,000 lbs (you'll have to correct me here too, since you know first-hand how much fuel an hour's travel at cruise would take).

The wings are still producing twice the lifting force than the total engine thrust force. That's all I'm getting at. The wake turbulence behind an airplane is mostly due to the lifting force of the wings, with the engines playing a minor (but not non-existant) part.

[edit on 2-6-2008 by HLR53K]

[edit on 2-6-2008 by HLR53K]

Originally posted by HLR53K
I don't know where you got your statement of everyone saying jet exhaust/wash makes up the majority of the wake turbulence.

How many sources do i need?

en.wikipedia.org...

Wake turbulence is turbulence that forms behind an aircraft as it passes through the air. This turbulence includes various components, the most important of which are wingtip vortices and jetwash. Jetwash refers simply to the rapidly moving gasses expelled from a jet engine; it is extremely turbulent, but of short duration

reply to post by ULTIMA1


At a -5 degree pitch the majority of that jet wash would be directed into the sky, not at the ground. The effects the cars felt are just about right and the witnesses plus the FDR report that -ve pitch.

It all makes sense whereas alternative ideas do not and need to deny all the evidence to have a chance of working.

Originally posted by ULTIMA1

How many sources do i need?

en.wikipedia.org...

Wake turbulence is turbulence that forms behind an aircraft as it passes through the air. This turbulence includes various components, the most important of which are wingtip vortices and jetwash. Jetwash refers simply to the rapidly moving gasses expelled from a jet engine; it is extremely turbulent, but of short duration

Plenty more if you want to argue on my level. I've shown you using numbers that your "jetwash" makes up the minority.

Do you argue that 73,200 lbs of thrust is less than the 200,000 lbs of lift the wings are producing at a minimum?

But it's nice to see you finally showed a quote in its full. Note the bolded text. No one's arguing that jetwash isn't turbulent, but it's very short-lived as your quote states, so it doesn't have a huge impact.

Originally posted by ULTIMA1

Originally posted by TheTraveler
Ultima1,
I'm an ex USAF jet engine tech with flightline and testcell experience on large aircraft. Your reasoning was flawed in your original argument about thrust.

So your stating everyone else is wrong when they state that JETWASH is main part of wake turbulence?

You are the only one thats right?

I wasn't addressing the issue of wake turbulence only the effects of a jet engine's exhaust.

Originally posted by HLR53K
Plenty more if you want to argue on my level. I've shown you using numbers that your "jetwash" makes up the minority.

You have to remember the words "mostly", "majority", and "no" don't mean the same thing in the Ultima-lexicon. The F-4 is "mostly" steel. The "majority" of fuel burned in the initial explosion, there is "no" evidence of the plane hitting the Pentagon, etc. So when he says most of "jet blast", we just have to assume it means "part" and not correct him or be drawn into a topic that we've already discussed quite thoroughly.

Originally posted by HLR53K

Plenty more if you want to argue on my level. I've shown you using numbers that your "jetwash" makes up the minority.

Do you argue that 73,200 lbs of thrust is less than the 200,000 lbs of lift the wings are producing at a minimum?

Not that i think that Ultima knows what he's talking about, but would a -5 angle at 500 mph result in some negative G and decrease the amount of lift being generated by the wings?

Just a weird technical issue that has me curious. Thx.

Originally posted by HLR53K
No one's arguing that jetwash isn't turbulent.

Well then why can't you agree that if the plane was low enough to hit an antenna it would rock the cars on the highway?

Originally posted by _Del_
The "majority" of fuel burned in the initial explosion, there is "no" evidence of the plane hitting the Pentagon,

1. I have posted several reports that state the MAJORITY of fuel burned off.

2. There is no actual evidence of AA77 hitting the Pentagon.

Originally posted by Seymour Butz

Not that i think that Ultima knows what he's talking about, but would a -5 angle at 500 mph result in some negative G and decrease the amount of lift being generated by the wings?

Just a weird technical issue that has me curious. Thx.

Without doing any number crunching, I would have to say that an AoA of -5 degrees might not result in any less lift than its +5 degree counterpart.

If you had a symmetrical airfoil, then it wouldn't matter what AoA you're at (between the + and - side). Since most, if not all, modern airplanes have some sort of camber in the airfoil, the camber would affect the airflow, but to any noticeable degree, I doubt.

It really matters on which direction the airflow is traveling relative to the airfoil. If you think about it, if it's a calm day, then the airfoil is still cutting through the same "block" of air, regardless of its AoA.

Originally posted by ULTIMA1

Well then why can't you agree that if the plane was low enough to hit an antenna it would rock the cars on the highway?

So you're saying there was a 757 at the Pentagon? If there wasn't one, then why are you using those witness statements? Wouldn't it be a moot point if there was no 757 as you claim?

Originally posted by HLR53K
So you're saying there was a 757 at the Pentagon? If there wasn't one, then why are you using those witness statements?

As stated, i said a plane not a 757. Do you have a problem reading or just trolling?

Originally posted by ULTIMA1

As stated, i said a plane not a 757. Do you have a problem reading or just trolling?

Ok, I missed that. I'm in the middle of building a concept design at work, so I read all the posts really quick. Thanks for the quick jump to insults though.

Anyway, I'm curious as to what you think hit it then. Since we can agree that it was an airplane, what size would be the question.

Originally posted by ULTIMA1
1. I have posted several reports that state the MAJORITY of fuel burned off.

2. There is no actual evidence of AA77 hitting the Pentagon.

1. You have not.

2. You have not chosen to acknowledge the evidence of AA77 hitting the Pentagon.