What hit the pentagon on 9/11/01?

reply to post by turbofan

Just plain incredible!

YES, you are.

The air is thinner up there... SURE YOU CAN FLY AT 462 KNOTS AT 35,000
feet!

The freakin' cruising speed for a 757/767 is 500+ knots at 35,000 FEET!

Well, I assume the first sentence in the above quote is sarcasm, eh? Because based on your second sentence you HAVE NO IDEA what you're talking about. Seriously. Stop. You're embarrassing yourself.

OH MY GOD. YOU ARE NOT A PILOT! YOU CANNOT BE A PILOT!

We've certainly established that YOU aren't a pilot. See above.

WEEDWACKER, if you fly 462 knots at sea level and 462 knots at 35,000 feet, WILL THE PLANE EXPERIENCE THE SAME DYNAMIC PRESSURE.

No. I've already stated that, numerous times. BUT, you began this on "Equivalent Airspeed", but now you've flipped the script and wish to talk about dynamic pressure? Fine. EAS is, as I've pointed out, irrelevant to the performance engineering of flight, it is only important to the structural engineering. It's in one of the sources I've cited.

BTW, please learn up on what TRUE AIRSPEED means, and how INDICATED/CALIBRATED AIRSPEED differs with altitude (and thus, air density and compressibilty efects).

These concepts aren't secret, they have definitions available to anyone online. BUT, to some who aren't pilots it seems a difficult concept to grasp.

IT CAN"T BECAUSE THE AIR IS LESS DENSE!

Correct. The air IS lense dense at 35,000 than at sea level. Everyone konwws that, I know that and have never stated otherwise. The fact is, the "dynamic pressure" that the airframe experiences at the very high airspeeds seen with AA 77 is higher than would normally be experienced in the life of the airframe....but it would NOT result in immediate disintegration.

The airspeeds would have to be sustained for a long time...AND/OR a severe and abrupt control input made that would cause an over-stress to the airframe (whether by an excessive g-force in pitch, or too much aileron...but if you want to break something faster, you do it with pitch).

After such an event (462 knots at sea level) were you to actually do that, (remember when I said the ONLY way to get up to that kind of speed, in that kind of jet, is by the use of engine thrust AND gravity...) and then return to land, and inspect you will find damage. Exactly how much, where and how it will affect the life of the airframe I don't know.

BUT...the primary components will be intact....wings, horizontal and vertical stabs...and engines, as well. Inspection panels, fairings and other types of components not important to structural integrity may come off, after a long enough time at those speeds.

OH, darn. I talked too much again...



[edit on 30 September 2009 by weedwhacker]

reply to post by weedwhacker

Originally posted by weedwhacker
reply to post by turbofan

 

The air is thinner up there... SURE YOU CAN FLY AT 462 KNOTS AT 35,000
feet!

The freakin' cruising speed for a 757/767 is 500+ knots at 35,000 FEET!

Well, I assume the first sentence in the above quote is sarcasm, eh? Because based on your second sentence you HAVE NO IDEA what you're talking about. Seriously. Stop. You're embarrassing yourself.

I've done some research and I think I can now explain what I think turbofan is missing...

1- Mach 1 varies according to altitude and, below the stratosphere, according to temperature as well. Cases in point:

a- Mac 1 at sea level= 340.3 m/s, 761.2 mph, 1,225 km/h

b- Mac 1 at 11,000 m (36,000 ft)= 295 m/s, 654.6 mph, 1,062 km/h, 86% of its speed at sea level.

2- The Boeing 757 is... [an] aircraft optimized for a cruising speed of Mach 0.8.

Therefore, the cruising speed for a Boeing 757 at 35,000 feet is 654.6 (35,000 feet is still in the stratosphere)/0.8= 523.68 mph

1 knot = 1.151 mph

So, converting the miles per hour to knots:
523.68/1.151= 455 knots.

So clearly, the cruising speed for a boeing at 35,000 feet is somewhat lower then 500+ knots at 35,000 feet.


But we're not really interested in the cruising speed of the plane at 35,000 feet, but rather what it was near sea level. So, working from the speed of Mach at sea level:
761.2 mph

Times by 0.8 to get the cruising speed of the boeing at that level:
761.2*0.8= 609 mph

Converted to knots:
609/1.151= 529 knots

So, while we haven't accounted for temperature, which is a factor below the stratosphere (I'm guessing it varies the air pressure), it would appear that the cruising speed for a Boeing 757 at sea level is, indeed, a bit over 500 knots.

I still maintain that the main issue is the one that Rob Balsamo mentioned in one of his videos; that is, that in order to both hit the light poles and then hit the pentagon low and level, the plane would have had to have pulled out of a dive of atleast 10 gs, something that a 757 simply can't do; and that G load would more than triple if we are to believe the NTSB data.

[edit on 30-9-2009 by scott3x]

Originally posted by scott3xSo, while we haven't accounted for temperature, which is a factor below the stratosphere (I'm guessing it varies the air pressure), it would appear that the cruising speed for a Boeing 757 at sea level is, indeed, a bit over 500 knots.

You had it right up until this paragraph.

The cruising speed of a 757/767 is not 500 knots at sea level.

The aircraft has been limited by the manufacturer at 360 knots VMo.

Look at this another way...it might help to understand:

IF...IF... a 767 could fly at 510 knots at sea level (without breaking apart,
or going out of control), it has enough power available to travel over
Mach 1 (the speed of sound) at 35,000 feet.

IF...IF... the engines were able to move the aircraft through more dense
air at 510 knots, it will be able to move the plane at an equivalent speed
[EAS] of over Mach 1 at higher altitudes in less dense air (less aero drag).

At this equivalent speed, the aircraft is experiencing the same forces from
air pressue as it would traveling at 510 knots at sea level.

Does this make sense now?

If you agree that the aircraft can move at 510 knots at sea level in control
and 'safe structural' flight, then you must agree that the same plane can
break the sound barrier at 35,000 feet.

Ask yourself if this is possible.

[edit on 30-9-2009 by turbofan]

reply to post by turbofan

Originally posted by turbofan

Originally posted by scott3x
So, while we haven't accounted for temperature, which is a factor below the stratosphere (I'm guessing it varies the air pressure), it would appear that the cruising speed for a Boeing 757 at sea level is, indeed, a bit over 500 knots.

You had it right up until this paragraph.

The cruising speed of a 757/767 is not 500 knots at sea level.

The aircraft has been limited by the manufacturer at 360 knots VMo.

I doubt it makes much of a difference, but according to this page, the VMo for the 757 and the 767 are actually slightly different; the 767 is the one with the 360 knots VMo; the 757 has it at 350 knots. 767 that has the VMo at 360 knots.

Originally posted by turbofan
Look at this another way...it might help to understand:

IF...IF... a 767 could fly at 510 knots at sea level (without breaking apart,
or going out of control), it has enough power available to travel over
Mach 1 (the speed of sound) at 35,000 feet.

I'm not sure how fast a 757 could travel at 35,000 feet, knots wise. However, I think it would probably be good to introduce the following link:
www.seattle911visibilityproject.org...

Quoting from it:

Here is how you figure out how fast a 767 can go at 700 ft (basically sea level)
We see that the "speed limit" is much lower at sea level than at 30k. 403 mph at sea level, and 581 mph at 30000 ft. But now the rubber to the road question is, how much beyond the "speed limit" can a Boeing 757 or 767 airplane be taken? To exceed Vmo/Mmo is not catastrophic. Boeing notes higher speeds can be authorized. To quote the Boeing Flight Ops review: "At speed in excess of Vmo/Mmo ... normal airplane handling characteristics are not assured." What they are saying is that an airplane can be taken somewhat beyond Vmo/Mmo by a skilled pilot. We would expect a safety factor of at least 10%, probably more like 20% or 30%, before structural damage may result.

How much beyond the "speed limit" can a Boeing 757 or 767 airplane be taken? Pilots For 9/11 Truth asked that question over a year ago, and still do not have an answer. It is fairly well established that Vmo is about 400 mph at sea level, but no solid numbers for Vne have been documented. While this question is still in the hopper, the assumption by Pilots For 9/11 Truth has been that all of the alleged manuvers of the airplanes on 9/11 were within the scope of a skilled pilot and the Boeing aircraft.

The "flight 175 Impossible speed" Thrust-Drag Argument has been mentioned on the internet.

The argument is basically this: thrust must increase 134-fold to maintain the same 542 mph it had at 35,000' altitude down at 1,000' altitude. I believe this is defintely wrong. First, the quantity given for air density in this "thrust/drag argument " is incorrect: The air density quoted is for 35000 meters, or 114829 ft, not 35000 ft. At 114829 ft, not only would you not be able to breathe, but you would also explode, so it looks like someone got meters and feet mixed up in thier calculations.

The 757 or 767 has enough engine thrust to go about as fast at sea level as at 30000 ft. Here is why I believe that: Thrust increases by about the needed amount to compensate for the difference in air density between the higher and lower elevation.

At lower altitudes and denser air structural damage may occur due to vibration or flutter, while at higher altitudes and thiner air, structural damage due to shock waves may occur. Thats what the "speed Limits" are all about. The key question is, by how much can a 767 (or 757) exceed Vmo without incuring structural damage , and at this point, we just do not know.

Originally posted by turbofan
IF...IF... the engines were able to move the aircraft through more dense
air at 510 knots, it will be able to move the plane at an equivalent speed
[EAS] of over Mach 1 at higher altitudes in less dense air (less aero drag).

But then there's the issue of increased thrust at lower altitudes; I'm guessing it has to do with the increased air density.

Originally posted by turbofan
At this equivalent speed, the aircraft is experiencing the same forces from
air pressure as it would traveling at 510 knots at sea level.

Does this make sense now?

It does, but after taking a look at the formula for equivalent air speed, I admit I'll have to take your word that 510 knots at sea level = Mach 1 + at 35,000 feet. What I'd like to know is, does weedwacker agree?

Originally posted by turbofan
If you agree that the aircraft can move at 510 knots at sea level in control
and 'safe structural' flight, then you must agree that the same plane can
break the sound barrier at 35,000 feet.

Ask yourself if this is possible.

Honestly, I don't know. Hopefully you'll respond to that link from seattle911; I note that he also says 30,000 feet instead of 35,000 feet; the author is using PFT as his back up though; since you haven't been banned from PFT, you can ask them directly if he's characterizing what they said right.

reply to post by scott3x


scott, applause for this post. Fortunately, I took a break after reading a post or two above, where I thought you needed some gentle corrective nudging, but it looks like you're learning quite well on your own.

Really, for non-pilots (and laymen) you aren't going to find as much info from the Internet as people like me who've actually flown the airplanes will be able to tell you.

Of course, since what I say about how to operate the airplanes isn't always available ON the internet for you to check, and since no one wants lessons from me ( ) then I'll stick to checking and clarifying what you're already learning.

I doubt it makes much of a difference, but according to this page, the VMo for the 757 and the 767 are actually slightly different; the 767 is the one with the 360 knots VMo; the 757 has it at 350 knots. 767 that has the VMo at 360 knots.

Note #1: You are following the style of "turbo" here...in all of my Flight Manuals and training materials, it is either "Vmo" or "VMO". Picky, but....

Note #2: I was teasing about being picky, because you have a sharp eye, and caught something that "turbo" obviously never noticed.

Originally posted by turbofan
Look at this another way...it might help to understand:

IF...IF... a 767 could fly at 510 knots at sea level (without breaking apart,
or going out of control), it has enough power available to travel over
Mach 1 (the speed of sound) at 35,000 feet.

Ermmmm...once again, in the Pentagon thread about AA 77, "turbo" goes off the rails here....but, this is his mantra, and it's wrong. He is forgetting about the effects of using gravity AND thrust to accelerate beyond a speed that would be achievable in level flight with thrust only.

---------------------------------------------

I'm not sure how fast a 757 could travel at 35,000 feet, knots wise. However, I think it would probably be good to introduce the following link:
www.seattle911visibilityproject.org...

Since MMO (or, if you prefer, "Mmo") is M.88, then simply solve for M.88 at FL350, standard temperature. You will then find the TAS that is equivalent. Hang on, I'll do it..... OK, I'm back:

When you reach M.88 at FL350, in standard temp for that altiude (-54.3C) your TAS is 507Kt, and the CAS is 303Kt. (CAS is what the airpeed indicator should read, +/- a few knots. It's important, here, to also point out that the 'barber pole' that I mentioned many posts back, while it is normally at the 350Kt or 360Kt position (depending on airplane) will move, as altitude increases into the Mach regime, to reflect MMO, instead of VMO...because MMO is more limiting, from a CAS standpoint, at thigher altitudes. Oops, surprise lesson....sorry.

Quoting from it:

Here is how you figure out how fast a 767 can go at 700 ft (basically sea level)
We see that the "speed limit" is much lower at sea level than at 30k. 403 mph at sea level, and 581 mph at 30000 ft. But now the rubber to the road question is, how much beyond the "speed limit" can a Boeing 757 or 767 airplane be taken? To exceed Vmo/Mmo is not catastrophic. Boeing notes higher speeds can be authorized. To quote the Boeing Flight Ops review: "At speed in excess of Vmo/Mmo ... normal airplane handling characteristics are not assured." What they are saying is that an airplane can be taken somewhat beyond Vmo/Mmo by a skilled pilot. We would expect a safety factor of at least 10%, probably more like 20% or 30%, before structural damage may result.

How much beyond the "speed limit" can a Boeing 757 or 767 airplane be taken? Pilots For 9/11 Truth asked that question over a year ago, and still do not have an answer. It is fairly well established that Vmo is about 400 mph at sea level, but no solid numbers for Vne have been documented. While this question is still in the hopper, the assumption by Pilots For 9/11 Truth has been that all of the alleged manuvers of the airplanes on 9/11 were within the scope of a skilled pilot and the Boeing aircraft.

The "flight 175 Impossible speed" Thrust-Drag Argument has been mentioned on the internet.

The argument is basically this: thrust must increase 134-fold to maintain the same 542 mph it had at 35,000' altitude down at 1,000' altitude. I believe this is defintely wrong. First, the quantity given for air density in this "thrust/drag argument " is incorrect: The air density quoted is for 35000 meters, or 114829 ft, not 35000 ft. At 114829 ft, not only would you not be able to breathe, but you would also explode, so it looks like someone got meters and feet mixed up in thier calculations.

The 757 or 767 has enough engine thrust to go about as fast at sea level as at 30000 ft. Here is why I believe that: Thrust increases by about the needed amount to compensate for the difference in air density between the higher and lower elevation.

At lower altitudes and denser air structural damage may occur due to vibration or flutter, while at higher altitudes and thiner air, structural damage due to shock waves may occur. Thats what the "speed Limits" are all about. The key question is, by how much can a 767 (or 757) exceed Vmo without incuring structural damage , and at this point, we just do not know.

Originally posted by turbofan
IF...IF... the engines were able to move the aircraft through more dense
air at 510 knots, it will be able to move the plane at an equivalent speed
[EAS] of over Mach 1 at higher altitudes in less dense air (less aero drag).

But then there's the issue of increased thrust at lower altitudes; I'm guessing it has to do with the increased air density.

Good guess, critical reasoning...BUT there is still that pesky issue of drag.

~Caution: Lesson approaching!~ We are interested, here, in two types of drag: Parasitic (sometimes called 'form') drag, and Induced drag.

Parasitic is obvious, and is a direct result of forcing a body (airplane) through a fluid (air). It is an inverse curve relationship to speed.

Induced drag is related to the creation of lift. THEREFORE it varies by speed AND angle of attack.

~lesson ending~

Originally posted by turbofan
At this equivalent speed, the aircraft is experiencing the same forces from
air pressure as it would traveling at 510 knots at sea level.

Does this make sense now?

It does, but after taking a look at the formula for equivalent air speed, I admit I'll have to take your word that 510 knots at sea level = Mach 1 + at 35,000 feet. What I'd like to know is, does weedwacker agree?

scott, you found that page from Wiki with the EAS formula...it's easier to use the one I linked before, from www.aerospaceweb.org...

Again, as I mentioned about, "turbo" just can't let go of one idea, and he's wrong.

As you can no doubt calculate by now, and realize, Mach 1 at sea level is well above 510Kt. (Yes, I'm using that one now, because it's worst case scenario...from the three that hit buildings).

Originally posted by turbofan
If you agree that the aircraft can move at 510 knots at sea level in control
and 'safe structural' flight, then you must agree that the same plane can
break the sound barrier at 35,000 feet.

Ask yourself if this is possible.

Sigh. Again, "turbo" is making an illogical assumption, and comparison. He is, still, completely misunderstanding the concepts of Indicated versus True airpeeds, and the Mach number relationships of air temperature and speed.

Honestly, I don't know. Hopefully you'll respond to that link from seattle911; I note that he also says 30,000 feet instead of 35,000 feet; the author is using PFT as his back up though; since you haven't been banned from PFT, you can ask them directly if he's characterizing what they said right.

Hopefully he will. We are all hoping he will.




[edit on 30 September 2009 by weedwhacker]

Originally posted by weedwhacker
Of course, since what I say about how to operate the airplanes isn't always available ON the internet for you to check, and since no one wants lessons from me

Because there are pilots that are confirmed as pilots that contradict this stranger on the internet. Who would you believe? A known pilot or a name on the internet claiming to be one? Honestly, if you were me and you had those two choices, which way would you go?

reply to post by Lillydale


If I were you....?????

I would find a pilot I knew, and have him/her read what I write.

I read what some of these P4T 'pilots' write, and others that I know look at it, and we laugh....not very gently, sometimes.

AND.....isn't it interesting that OTHER pilots have come out ON THE INTERNET to refute the P4T???? Ever wonder WHY the P4T has such a small membership??? When you consider the number of airline pilots, just in the U.S. ---



[edit on 30 September 2009 by weedwhacker]

reply to weedwhacker's post #345, part 1

Originally posted by weedwhacker
reply to post by scott3x

 

scott, applause for this post.

Thanks :-). I've decided to add you to my friends list. I find it ironic that you've treated me better then some of the people who are on my side of the pentagon debate in general, but that's life for you :-p.

Originally posted by weedwhacker
Fortunately, I took a break after reading a post or two above, where I thought you needed some gentle corrective nudging, but it looks like you're learning quite well on your own.

Really, for non-pilots (and laymen) you aren't going to find as much info from the Internet as people like me who've actually flown the airplanes will be able to tell you.

I agree, which is why I asked so many questions over at Pilots for 9/11 Truth, where they have some pretty seasoned pilots. Unfortunately, Rob Balsamo, a fairly seasoned pilot and the founder of the site, as well as being instrumental to creating various Pilots for 9/11 Truth videos, didn't hit it off so well with me; I imagine this is why he came to the false conclusion that I had "lied" about something, decided I was a "troll", and banned me until December, when in truth I'd simply made an innocent mistake.

Originally posted by weedwhacker
Of course, since what I say about how to operate the airplanes isn't always available ON the internet for you to check, and since no one wants lessons from me (

) then I'll stick to checking and clarifying what you're already learning.

I don't mind lessons, laugh ;-). I wish I could have gotten more over at PFT, instead of sometimes being sent to ponderous links to try to figure things out myself.

[edit on 30-9-2009 by scott3x]

Originally posted by weedwhacker
reply to post by Lillydale

 

If I were you....?????

I would find a pilot I knew, and have him/her read what I write.

What would you do when two of them laughed quite hard at your idea that basically all airplanes act and react the same no matter the type and no matter the climate or altitude?

Anyway, it really does not matter what I say or you say about what we are or have. All that matters is what you put down in words here and you summed up all flight as "up is still up." You trip over your own faulty logic and most people can read that pretty clearly. Keep saying you are a pilot and see if repetition forces belief.

reply to weedwhacker's post #245, part 2

Originally posted by weedwhacker

I doubt it makes much of a difference, but according to this page, the VMo for the 757 and the 767 are actually slightly different; the 767 is the one with the 360 knots VMo; the 757 has it at 350 knots. 767 that has the VMo at 360 knots.

Note #1: You are following the style of "turbo" here...in all of my Flight Manuals and training materials, it is either "Vmo" or "VMO". Picky, but....

Note #2: I was teasing about being picky, because you have a sharp eye, and caught something that "turbo" obviously never noticed.

Only a detail though, laugh :-). Anyway, wikipedia uses VMO, so I'll stick with that from now on I think ;-).

Originally posted by weedwhacker

Originally posted by turbofan
Look at this another way...it might help to understand:

IF...IF... a 767 could fly at 510 knots at sea level (without breaking apart,
or going out of control), it has enough power available to travel over
Mach 1 (the speed of sound) at 35,000 feet.

Ermmmm...once again, in the Pentagon thread about AA 77, "turbo" goes off the rails here....but, this is his mantra, and it's wrong. He is forgetting about the effects of using gravity AND thrust to accelerate beyond a speed that would be achievable in level flight with thrust only.

Mm. Based on the material below, I have doubts as to whether turbofan is right here. I have noted that turbofan did, in fact, ask about this issue over at PFT, but has yet to receive a response:
pilotsfor911truth.org...

So guess we'll have to manage without them for now...

Originally posted by weedwhacker

Originally posted by scott3x
I'm not sure how fast a 757 could travel at 35,000 feet, knots wise. However, I think it would probably be good to introduce the following link:
www.seattle911visibilityproject.org...

Since MMO (or, if you prefer, "Mmo") is M.88,

For those who may not know, MMO stands for Maximum Mach Number at which an aircraft has been certified to operate. (why they didn't call it MMN I don't know :-p). I assume that weedwacker means that the Boeing 757's MMO is Mach .88. I personally could only find its cruise speed on the Boeing 757 wiki page:
Mach 0.80 (530 mph, 458 knots, 850 km/h at cruise altitude, i.e. 35,000 ft or 10.66 km)

Originally posted by weedwhacker
then simply solve for M.88 at FL350, standard temperature.

Lost you here, laugh :-). Mach .88 I get. But what does FL350 mean? And how do you figure out what the standard temperature is at any given altitude? Also, I'm not sure what I'm trying to solve or how I should go about solving it ;-).

Originally posted by weedwhacker
You will then find the TAS that is equivalent. Hang on, I'll do it..... OK, I'm back:

When you reach M.88 at FL350, in standard temp for that altiude (-54.3C) your TAS is 507Kt, and the CAS is 303Kt. (CAS is what the airpeed indicator should read, +/- a few knots. It's important, here, to also point out that the 'barber pole' that I mentioned many posts back, while it is normally at the 350Kt or 360Kt position (depending on airplane) will move, as altitude increases into the Mach regime, to reflect MMO, instead of VMO...because MMO is more limiting, from a CAS standpoint, at thigher altitudes. Oops, surprise lesson….sorry.

Lol :-). All of this is just too much information right now; I wiki'd Indicated airspeed; quite a bit to absorb.

Originally posted by weedwhacker

Originally posted by scott3x

Originally posted by turbofan
IF...IF... the engines were able to move the aircraft through more dense air at 510 knots, it will be able to move the plane at an equivalent speed [EAS] of over Mach 1 at higher altitudes in less dense air (less aero drag).

But then there's the issue of increased thrust at lower altitudes; I'm guessing it has to do with the increased air density.

Good guess, critical reasoning...BUT there is still that pesky issue of drag.

~Caution: Lesson approaching!~ We are interested, here, in two types of drag: Parasitic (sometimes called 'form') drag, and Induced drag.

Parasitic is obvious, and is a direct result of forcing a body (airplane) through a fluid (air). It is an inverse curve relationship to speed.

Induced drag is related to the creation of lift. THEREFORE it varies by speed AND angle of attack.

~lesson ending~

Ok...

[edit on 30-9-2009 by scott3x]

Originally posted by turbofan
reply to post by weedwhacker

 

Well, go ahead and prove it then. Everyone is on the same page with
me...except for you it seems!

So, go ahead and prove that you understand what I have been asking for
5+ pages.

Show me that you understand that a plane moving 462 knots at sea level
must travel over mach 1 at 35,000 feet to experience the same dynamic
pressure due to the difference in air density.

Waiting...

Hey turbo, spinsters and spooks are just stupid. ignorant, nut job. wacko, liars.
And we all know it.
Anyone that does not understand what you say is a numbskull.
High speed over topography in a jet the size of the fantasy one alleged to have crashed into the pentagon would cause such buffeting as to make the craft close to impossible to control. Even with a pilot of above average credentials. I have seen no evidence of any here. I don't recall you saying you were one.

That is why low level high speed aircraft have the most sophisticated radar and the computers to fly the aircraft, not the pilots. Mostly fighters or fighter bombers. Anyone who is not mentally handicapped can understand this concept. Commercial pilots too.
I think most of the wack jobs on this thread have never flown anything but the simulation mock-up at the Areo Space Museum in D. C. "Holy crap I just put that baby down on the carrier deck. I must be an ATS pilot!!!" "Me and some aviation web site." "Holy crap I'm an ATS pilot."

reply to weedwhacker's post #245, part 3

Originally posted by weedwhacker

Originally posted by scott3x

Originally posted by turbofan
At this equivalent speed, the aircraft is experiencing the same forces from
air pressure as it would traveling at 510 knots at sea level.

Does this make sense now?

It does, but after taking a look at the formula for equivalent air speed, I admit I'll have to take your word that 510 knots at sea level = Mach 1 + at 35,000 feet. What I'd like to know is, does weedwacker agree?

scott, you found that page from Wiki with the EAS formula...it's easier to use the one I linked before, from www.aerospaceweb.org...

I assume you mean the Atmospheric Calculator, the Compressible Flow Calculator, or both. While they may be easier, they still don't seem to be all that easy :-p.

Originally posted by weedwhacker
Again, as I mentioned about, "turbo" just can't let go of one idea, and he's wrong.

As you can no doubt calculate by now, and realize, Mach 1 at sea level is well above 510Kt. (Yes, I'm using that one now, because it's worst case scenario...from the three that hit buildings).

As I think I've made clear in this post, I can't yet do that calculation. But what idea is it that turbo just can't let go of? Also, not sure what you mean concerning this 'worst case scenario' bit...

reply to weedwhacker's post #245, part 4 (last part)

Originally posted by weedwhacker

Originally posted by turbofan
If you agree that the aircraft can move at 510 knots at sea level in control
and 'safe structural' flight, then you must agree that the same plane can
break the sound barrier at 35,000 feet.

Ask yourself if this is possible.

Sigh. Again, "turbo" is making an illogical assumption, and comparison. He is, still, completely misunderstanding the concepts of Indicated versus True airpeeds, and the Mach number relationships of air temperature and speed.

I still can't follow you here weedwhacker...

Originally posted by weedwhacker

Originally posted by scott3x
Honestly, I don't know. Hopefully you'll respond to that link from seattle911; I note that he also says 30,000 feet instead of 35,000 feet; the author is using PFT as his back up though; since you haven't been banned from PFT, you can ask them directly if he's characterizing what they said right.

Hopefully he will. We are all hoping he will.

Well, as I indicated in a previous post, he has, but there were a lot of posts there recently because they were discussing Frank Legge's new revisions to his paper regarding the pentagon attack and apparently they missed responding to his question...

Are there any fellow pilots worth their salt whom could explain the lightpoles being hit and the 762 engines somehow, miraculously, not making lovely furrows on the pentalawn? Or the folding wings which didn't cause damage away from the urrr... 'hole' like the wtc1 and 2s cutout planes?

[edit on 30/9/09 by GhostR1der]

I was teasing about being picky, because you have a sharp eye, and caught something that "turbo" obviously never noticed.

never noticed? I guess you didn't notice the links to 757, and 767
manufacturer performance which I posted on page 11 when discussing
structural limits. VMo is stated for each aircraft there.

I guess you didn't bother watching the video I posted on the previous page which also outlines the differences between 757/767 through an
interview with Rusty Aimer. A veteran pilot who has flown both aircraft
inlcuding the alleged UA175 and UA 93.

Please don't assume I didn't know the max. operating for a 757 since
I grouped both planes together giving you the higher VMo.

Ermmmm...once again, in the Pentagon thread about AA 77, "turbo" goes off the rails here....but, this is his mantra, and it's wrong. He is forgetting about the effects of using gravity AND thrust to accelerate beyond a speed that would be achievable in level flight with thrust only.

Quick someone find the post where Weedwacker states that you wuold
have to nose down the plane to reach such speeds, and he even stated
that nosing down the aircraft would be doubtful to reach such speeds.

Too bad neither aircraft was pitched down much at all! Contradict yourself
much Weed?

After reading through this last bit of debate, I see that you are finally on
deck with dynamic pressure. Now you've turned your opinion to the argument
that a 757/767 moving at 462/510 knots at sea level wont break apart
right away.

Why should we believe you when Egypt Air broke apart at mach 0.99
and 22,000 feet?

why should we believe you when Boeing limits their 757/767 to 360 knots?

If you studied AA77 FDR you will note there is more than a few seconds
of flight at excessive speeds.

If you studied the UA175 information, you will also note there were more
than a few seconds of extreme speeds.

Soooo...

#1. The manufacturer limits these commercial airliners to 360 knots.

#2. We have video of wind tunnel flutter tests showing oscillations and stressing of components on the airframe.

#3. We have an example of a 767 via Egypt Air which breaks apart
at lower dynamic pressure in thinner air.

#4. We have a pilots encyclopedia warning of mach tuch, dutch roll,
and other "out of control" situations

#5. We have EXPERIENCED fighter pilots, check-air men, and 757/767
pilots who cannot hit towers in the simulators after several tries...and
can only do so once the speed has been reduced to near LANDING SPEEDS

but..."Weedwacker" says the planes should stay together and be fairly
easy to control hitting 3 out of 3 targets SPOT ON by a bunch of rookie
terrorists?

I rest my case. You should all watch the video I posted, and check out
real pilots talking about this impossibility in P4T's latest presentation.
Educate yourselves and understand that hand flying a commercial airliner
at speeds WELL over their design limits is not a "point and shoot" game.

[edit on 1-10-2009 by turbofan]

Well, that was a long read.

First of I’d like to say it’s a strange topic. There are a couple of people who don’t agree whit Weedwhacker and will never agree nomather what he says. Then there are a couple of fencesitters who agree whit Weedwhacker but do not want to take part in the discussion.

Well, you can call me a fencesitter and I’d like to thank Weedwhacker. Keep up the good work. I learned a lot from you.

reply to post by turbofan


That post looks persuasive turbofan. Now to see what weedwhacker says, laugh ;-).

[edit on 1-10-2009 by scott3x]

reply to post by scott3x


Sorry scott... used shorthand AND made a mistake RE: the MMO for a B757:

Lost you here, laugh :-). Mach .88 I get. But what does FL350 mean? And how do you figure out what the standard temperature is at any given altitude? Also, I'm not sure what I'm trying to solve or how I should go about solving it ;-).

Had another airplane in mind, and typed M.88 INSTEAD of M.86 which IS the actual published MMO Limitation for the Boeing 757.

But what does FL350 mean?

Sorry again, I forget that the shorthand won't make sense to everyone...."FL" means 'Flight Level'.

Term 'Flight Level' refers to a pressure altitude when the altimeters are set in the Kollsman window to 29.92 in. hg. (inches mercury) or 1016 mb (millibars) as is the reference in most of the World, other than the U.S.

This is the internationally accepted STANDARD Sea Level Pressure.

Flight Levels are used above certain altitudes (depending on nation) for simplicity, especially in high-speed flights. Altitmeter corrections due to prevailing local differences are not needed this way, and eveyone is on an equal footing, with reference to their respective altitudes.

In North America, the change/over altitude is 18,000 (FL180) because this comfortably clears the highest mountainous terrain.

(Internationl pilots who fly overseas will know, for instance, that the "transistion altitude" varies by country...in the UK, fo rinstance, it is 6,000 feet (FL60).

Hope this unsolicited lesson isn't too offensive. AND hope it clears up some terms...

ON TOPIC....this is a question raised RE: American 77.

DID the hijacker piloting the airplane reset any of the altimeters to the 'local' setting? (30.22 that morrning, reported at KDCA - National Airport) Or, did the guy leave them at where they would have been set by the real pilots during the climb -- 29.92???

FYI, the difference there is about 300 feet. 1,000 feet equals about ONE inch, as a rule of thumb, at lower altitudes (like below 10,000 feet)

reply to post by turbofan



Oh dear....once again, a few corrections:

Too bad neither aircraft was pitched down much at all! Contradict yourself much Weed?

"neither"? I refer you to some of the video shots of UAL 175...long shots from the proper angles that clearly show a descent and level off JUST prior to impact.

AND, even though there is no video footage of AAL 77, there IS the SSFDR. When I watch it, I see a definite pitch attitude BELOW 0 degrees.

One thing you should know, and would NOT know unless you've flown the airplane, is that in normal level cruise flight, at NORMAL speeds, normal pitch attitude is between 3 and 4 degrees NOSE UP.

In a normal descent, such as passing the Top Of Descent point from Cruise and flying the arrival profile (a STAR or just the three-to-one ration we use as a rule) to destination, we rarely see anything more than 5 degrees NOSE DOWN. Sometimes, if we need to increase V/S (vertical speed) to meet a crossing restriction...and we're using the speed brakes and nosing down a bit...where we're sneaking up to the barber pole, then the pitch is around 5-7 degrees...anything more is uncomfortable.

After reading through this last bit of debate, I see that you are finally on
deck with dynamic pressure.

I brought up dynamic pressure, to show YOU why the EAS was useless in your argument.

Now you've turned your opinion to the argument that a 757/767 moving at 462/510 knots at sea level wont break apart
right away.

Haven't "turned" anything. It's always been my 'opinion' -- based on an understanding of the airplanes.

Why should we believe you when Egypt Air broke apart at mach 0.99 and 22,000 feet?

Because your comparison to the Egypt Air crash is not relevant. TWO different scenarios. Even the altitudes are different!!! Also, I've pointed out that the Captain of Egypt Air, who had been back in the cabin, rushed forward and thought he was helping the First Officer pull out of a dive, when in fact the F/O was pushing FORWARD on the column.

What I read was this caused a split elevator condition...the twisting forces of one elevator commanding 'UP' and the other 'DN' twisted the horizontal stab off...and you know what happens then.

Also...you said it yourself! M.99!! Do the math, use a calculator or the E6-B manual computer....462/510 knots at near sea level is NOWHERE near Mach.99

If you studied AA77 FDR you will note there is more than a few seconds of flight at excessive speeds.

If you studied the UA175 information, you will also note there were more
than a few seconds of extreme speeds.

Yes. Define "few". I've said that as 'few' as thirty seconds, assuming no excessive g loads should NOT result in immediate structural failure of critical components. I have said this repeatedly. Other sources I have found think the same way.


You are trying to be a dutiful spokesman for these 'pilots' who are in the minority opinion.

To wit:

#2. We have video of wind tunnel flutter tests showing oscillations and stressing of components on the airframe.

You found one of an A-6 from...how many years ago??? Find one of a Boeing, please.

#3. We have an example of a 767 via Egypt Air which breaks apart at lower dynamic pressure in thinner air.

"thinner" air? Do you know you can actually breath, and survive (if in decent health, and not exerting yourself) at 22,000 feet??? Mt. Kilimanjaro is nearly 20,000 at the summit. People climb it, and live (well...with supplemental O2, of course...climbing is hard work).

#4. We have a pilots encyclopedia warning of mach tuch, dutch roll, and other "out of control" situations

More irrelevance. 'Mach tuck' applies at very close to Mach speed...NOT at .70 - not at .80 - and not at .96 (as we saw in YOUR A380 video). Also, it dpends a great deal on the specific airplane, as to the onset of Mach tuck. Modern jetliners are designed to minimize its "danger"...it was more of a concern in the early days, such as the B707 and B727.

...which brings me to...'Dutch Roll'. Again, it is NOT a concern AT ALL on the B737, nor the B757/767 NOR the B777 (and I assume the B787 as well). It was NOT a concern on the DC-9/MD80 either, which I've flown. Nor on the DC-10 nor the Airbus A300.

'Dutch Roll' is a phenomenom that is related to the amount of sweep in the wings...more sweep, more tendency to Pilot Induced Oscillations, which is the proper term. Look it up, it isn't a secret. At least, not to pilots.

#5. We have EXPERIENCED fighter pilots, check-air men, and 757/767 pilots who cannot hit towers in the simulators after several tries...and can only do so once the speed has been reduced to near LANDING SPEEDS

You have a few...very, very few. I sincerely question their motivations, here. And I question the circumstances of these "attempts" to hit the Towers. And just how hard they actually "tried" -- or did they wish to 'fail' on purpose?????



[edit on 1 October 2009 by weedwhacker]

reply to post by GhostR1der

engines somehow, miraculously, not making lovely furrows on the pentalawn?

This has been discussed already at length. The notion of the engines having struck or "dragged" accross the lawn or the ground is incorrect. Obviously, there would have beenmarks AND the engine debris would have possibly been seen there, instead of well along the trajectory of the impact, inside.

Or the folding wings which didn't cause damage away from the urrr... 'hole' like the wtc1 and 2s

Wings don't 'fold' back. This is another 'meme' that was started by someone on the "Truth movement" side.

It is simply that the fuselage had the majority of mass...next most massive single components are the engines.

However, the engines are not a solid piece, they are built of MANY separate (and sometimes fragile) pieces. Remember, that they were operating at very high power settings. The destructive forces involved would shred the blades from any turbines, leaving only the stronger central hubs.

The size of entry, given a different building type and structure, will be different where the engine pieces penetrated than seen in NYC. The Towers had more, and wider gaps between supporting columns.

Wing structures outboard of the engine mountings are just sheet aluminum, for the most part. Strong as a unit, when built, but will shatter in the type of impact seen. They were stronger vertically, than fore/aft.