Jet engine sim for testing 9/11 planes

Originally posted by ULTIMA1

Yes i could figure out most of the warning lights, they are called IDIOT lights for a reason.

Not all of them are IDIOT lights anymore.

Oh, they probably couldn't read English as well as you or I. So to make the comparison fair, I'd have to stick you in an A380 flight deck that wasn't in English.

However, that's a rare flight deck.

[edit on 15-4-2008 by HLR53K]

reply to post by ULTIMA1


A standard light pole is up to 35 feet. For flight 77 to have taken the poles out with their engines, that would mean they were at an altitude of at least 40 feet, to allow for the engines hanging down below the fuselage. At 40 feet, I don't care what power setting you have set, you're not going to be blowing cars around from jet blast.

Ok, I'm going to start over, since we've pretty much went off course.

You want us to put the engine at 60 feet because that's the closest the simulation will allow (other than 0 feet).

I have three questions for everyone:

1. How much time did the engine spend at 60 feet?
2. How long does it take for a turbofan engine to actually critically fail?
3. Could the engine have completely stopped working in the time the airplane spent at 60 feet?

Now, a better way to use this simulation would be to set the airspeed at around 500 knots. Then lower the altitude to see at what altitude the engine would have produced the temperature warning.

Then go to see where the airplane would have been at that altitude along its flight path into the Pentagon. Factor in the time it would have taken the engine to completely stop working from overheating and then see if it would have made it.

Just saying "the engine overheated at 60 feet" doesn't directly prove that a 757 didn't hit the Pentagon. All it says is that in the last minute of its flight the engines might have overheated.

Originally posted by HLR53K
Ok, I'm going to start over, since we've pretty much went off course.

You want us to put the engine at 60 feet because that's the closest the simulation will allow (other than 0 feet).

I have three questions for everyone:

1. How much time did the engine spend at 60 feet?
2. How long does it take for a turbofan engine to actually critically fail?
3. Could the engine have completely stopped working in the time the airplane spent at 60 feet?
Just saying "the engine overheated at 60 feet" doesn't directly prove that a 757 didn't hit the Pentagon. All it says is that in the last minute of its flight the engines might have overheated.

Okay, did a little digging. First thing I did was calculate the speed of the airplane in Feet Per Second, which is about 733 feet per second. Seems pretty fast to me.

As far as how long does it take for a turbofan to fail? Well, I got this:
Engine Failures
I realize that its written for a 737 turbofan, but the principles should be the same. The document doesnt elaborate on the time it takes for an engine to fail, but it alludes to systematic abuse and neglect causes this. The answer is probably out there, but Pratt and Whitney probably dont release that for obvious reasons.

In any case, covering 60 feet would be nearly instantly. After flight 77 made its turn towards the Pentagon, the distance between where it started and where it ended was about a mile or 5280 feet. To cover that distance at 730 fps would be about 7 seconds. Maybe to account for acceleration, lets be conservative and say 20 seconds. 20 seconds of pounding for engines that were regularly serviced and inspected is completely possible. I really doubt that in 20 seconds that these engines were even close to failure. And even if they had failed halfway there, failure wouldnt have caused the plane to drop like a rock, as suggested by these debunkers.

reply to post by DisInfo


See, was that not simple enough to do? I seriously doubt that going 10 Kelvin over the burn chamber "maximum" for 20 seconds is going to cause the engine to just stop.

And yes, I know you'll do exactly what I did, ULTIMA1, and say that because he used a 737, it won't apply.

Different circumstances. Doing the calculations for each stage of a turbofan engine will differ (maybe greatly) depending on how many stages the compressors and turbines have, the bypass ratio, materials used in the combustion chamber, etc..

However, the engines failures that he found are quite general across the board for most turbofans.

reply to post by DisInfo


DisInfo, you were joking about the airplane 'dropping like a rock' in the event of an engine, failure, weren't you? Yeah, thought so....

Interesting link, especially as referred to 'compressor surge'....what we always called 'compressor stall'.... when encountered in the old JT-9D turbojets, for instance....it was loud (think of a car backfiring, though a bad analogy) but ulitmate harmless....except in a high-bypass turbo fan engine. NOW you get damage, it is serious, and the engine gets changed.

Here's a true story...we were departing Paris, still in the climb (a DC-10-30) passing through about 27000 feet enroute to the NYC area. We heard a boom-boom-boom, and saw engine number 1 spool down. (F/F goes to zero, but still have N1 and N2 rotation). Of course, the generator tripped off, but the other two were on the sync bus, and carried the load.

Anyway, fairly routine engine failure, and obviously we're not going across the Atlantic now, so, since we were A) close to London and B) knew we had good maintenance in London, we diverted to London.

Well, the mechanics in London were peeved, because they expected us to have recorded the windmilling parameters for the 45 minutes or so after the event, until landing.

We told them....it was loud, and an obvious failure, why bother with 'windmilling'.

See, what we didn't know is, the engine had just been overhauled, and had only been back in service for about 400 hours, so the MX thought it was a fuel control unit problem, easily fixed. They dismissed our reports, and insisted it would only be a few hours, and we'd be on our way.

What they didn't want to do, is the hard thing....actually boroscoping the engine.

They fussed, and fussed....and finally, after five hours, they did a boroscope....and guess what? Most of the 'hot section' was gone! The engine could be started, on the ground, and would idle....but would not produce power, because the turbine section was mostly gone, a blade separated, and destroyed all the other stages behind it, as it exitied, aft!

I have to say, GE builds good engines....as long as the titanium rings that make up the stages stay intact, you can lose a blade, and it doesn't burst through the nacelle.

Modern turbofans are not tolerant of compressor 'surges' either, just so you know....but, they are designed such that, unless there's a mechanical failure, a compressor stall is unlikely.

WW

reply to post by weedwhacker


So, I pretty much hope we are both agreeing that a 757 could and did crash into the Pentagon. Having never flown a real airplane myself, I can appriciate the difficulty in such a task, and I myself probably couldnt do what the terrorists did, but they did have extensive flight training and did their homework.

The kinetic energy a plane 100 feet off the ground going 500MPH is huge. My concern or question to you, as a pilot:

At such a velocity, how hard would it be to keep on target?

reply to post by DisInfo


DisInfo, I was shown a YouTube link that addressed that very question.

Sorry I don't understand ATS enough to know how to link these things, but you can find it on YT easily enough, I assume....I think it was a B737-800 sim that was used. (while there are differences, the B737-800 is almost as large as a B757-200)

The clip on YT is from a documentary from....sounds like German or Dutch, but there are English subtitles.

Good hunting!

WW

Originally posted by HLR53K
Oh, they probably couldn't read English as well as you or I.

But didn't they need to read english to go to flight school?

Originally posted by Zaphod58
A standard light pole is up to 35 feet.

Show me a report that states how high the plane was over the highway.

So what, the light poles just fell over all by themselves? One minute they were standing there just fine, the next just *wham* over they went.

[edit on 4/16/2008 by Zaphod58]

[edit on 4/16/2008 by Zaphod58]

Originally posted by Zaphod58
So what, the light poles just fell over all by thenmselves?

I did not say anything about the poles, i asked for evidence from a report of how high the plane was above the highway.

Can you post the evidence or not?

The poles prove how high they were. And right this second no I can't. It's currently almost 3am and I have to be up for work in a couple hours.

But the fact that the poles were knocked over is a damn good clue as to just how high it was over the highway.

reply to post by ULTIMA1


Dude, ULTIMA....light poles are 'frangible'....they are designed to collapse, they are light (no pun).

Besides, it's been pointed out (and I just drove by the Pentagon today, to have a mental image) the airplane's momentum would carry it through, regardless of silly frangible obstacles like a light pole or a 'generator' truck!

No, the 'generator truck' (trailer) wasn't frangible.....but it was a split-second away, given the speed of AA77, before complete impact into the building. Thus, it is irrelevant.

I admire your persistance, ULTIMA....but must ask why you continue to demean the deaths of these people, based on flimsy logic, even as many continue to show the flaws in that logic?

If the 9/11 attacks were planned by the 'bush' administration, then I will just have to call that nonsense.

'bush' can't find his arse with both hands...not now, not then.

His newly installed 'cabinet', which included Condi Rice as Nat'l Security Advisor (what a joke, that!) couldn't be bothered to accept, as an 'in-briefing' a valid 'out-briefing' from the former Administration's advisors.

[edit....not sure of the correct terms, but I'd think that any new administration would be briefed in, by the out-going staff...]

Their idiotic arrogance led directly to 9/11. Because, warnings were evident, but ignored, by the 'Shrub' group.

Arrogant bastards, they all deserve to be put on trial for war crimes...but that's another thread....

WW

[edit on 4/16/0808 by weedwhacker]

Originally posted by Zaphod58
The poles prove how high they were. And right this second no I can't.

Were the poles on the highway or after the highway ?

Originally posted by weedwhacker
Dude, ULTIMA....light poles are 'frangible'....they are designed to collapse, they are light (no pun)

I am not talking about the poles i am talking about evidence of the hieght the plane was voer the highway.Please read posts before posting.

But maybe you can explain why the Flight77 FDR shows a different flight path and the plane did not hit the poles?

Originally posted by ULTIMA1
Were the poles on the highway or after the highway ?

Depends on your definition of highway. The nearby expressway wasn't under the flight path (official or conjectured) and two roads were crossed immediately before the Pentagon - the one passing the Citgo station then the one passing the Pentagon site and the poles hit were on those 2 carriageways. From pics of the site with typical light poles still standing I'd estimate their height at 25-30' and they are 'short outreach' types meaning they'd be located just off the road in order to illuminate the surface at night.

As I explained earlier using your own numbers, jet blast at that height would not be a significant factor for objects on the ground like people and vehicles. Not that there wouldn't be a disturbance, just that it wouldn't blow any vehicles off the road or even off course. I can only think of one person who could have been subjected to the jet exhaust but he dived onto the ground and safely avoided the worst, if not all, of it.

I've seen the suggestion that the poles were planted but I just can't see how 'they' could secretly stop traffic, drag poles onto the roadway and smash the light fittings all over the place without a lot of witnesses to contend with.

Originally posted by Pilgrum Not that there wouldn't be a disturbance, just that it wouldn't blow any vehicles off the road or even off course.

Well i never stated the jet blast did blow the vehicles off the road, i stated they were rocked by the jet blast.

Please read before posting.

...or possibly rocked by the wake turbulence. Not necessarily from jet blast.

The FAA has some nice fact sheets regarding wake turbulence....good for research.

Originally posted by Disclosed
The FAA has some nice fact sheets regarding wake turbulence....good for research.

Too bad you do not have any education or experience to know what you are talking about.

All you know how to do is quote what you read or what you have been told.