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gravity32
19th Mar 2011, 06:25
What is the maximum roll rate that can be achieved in a plane like a Boeing 757. I assume this is normally limited by the computer. Is the maximum roll rate affected by air speed? If there was no over-ride, what would be the maximum roll rate?

kenparry
19th Mar 2011, 12:56
On the B757 there is no computer that limits roll rate, it's not a fly-by wire system, simply mechanical powered controls with both ailerons and spoilers for roll control. Max roll rate is not relevant in normal operations, one never needs more than a gentle wheel input to achieve what is needed. I can't remember using in the air more than perhaps 20 degrees of the available 90 degrees of wheel movement. On the ground, for takeoff and especially landing with strong x-wind, much more will be used.

That's perhaps a long way of saying I can't answer the question directly, but I can tell you it is speed-dependent, with higher roll rates at higher speeds. TAS or IAS? There's a question!

Incidentally, the flight manual gives no figures and no limits.

Chris Scott
19th Mar 2011, 13:39
Forgive me for offering what amounts to off-topic trivia, but during my BAC111-200 conversion, our flight-controls groundschool instructor - who had worked at BAC - claimed that the roll-rate could equal that of the EE (BAC) Lightning in certain circumstances. As I recall, you needed to have the spoilers slightly extended (i.e., as medium airbrake) to achieve the best roll rate. (The spoilers on the upgoing wing would, of course, then retract.) Whether the speed was the higher the better, and whether that would be IAS or TAS related, I don't know.

Chris

main_dog
19th Mar 2011, 14:49
My guess would be IAS... and I would LOVE to see a BAC111 rolled like a Lightning... any clips?

:}

MD

A37575
19th Mar 2011, 15:06
In the simulator it takes six seconds to roll a 727-200 through 360 degrees as part of Jet Upset training.

barit1
19th Mar 2011, 16:38
Here's a lazy-er roll rate (10-11 sec.) in a plane that's not often rolled.
YouTube - Howard DGA 15 Barrell Roll

Chris Scott
19th Mar 2011, 16:57
main_dog,
Regret I cannot assist in that area. (And listen, we're talking about roll RATES, not rolling!) :ugh:

Unlike its big sister, the VC10, the One-Elevens all employ manual spring-servo-tab ailerons - not PCUs. Spoiler/Speedbrake surfaces are hydraulically powered, of course.

According to my hand-written course notes (in Doug Realff's lectures at the Bee Hive in 1977, re the 200 series): when speedbrakes (why don't we call them AIRbrakes?) are retracted, they do not lift as roll spoilers until 4deg of aileron, unlike the cruder system on the B707. This avoids spoilers cracking open in gentle turns or with aileron trim, and reduces initial roll rate. 4deg of aileron represents roughly 11 - 15deg of control-wheel movement.

However, with 10deg of speedbrake (half the maximum permitted in flight), the situation is slightly more volatile.
"...as soon as the (control wheel) is (fully) displaced, the spoilers will rise on the downgoing wing (to 43deg)......and the spoilers on the upgoing wing will retract. In this config, maximum roll rate is about 400deg per second."

Returning to the speed issue, the spoiler surfaces are designed to "blow back" at a certain air load. This would probably limit roll rate at high IAS, and presumably applies to all aircraft types. FBW types, no doubt, prevent that happening by limiting roll-rate (although blow-back of the surfaces can still occur in speedbrake mode).

Chris

fantom
19th Mar 2011, 18:13
RAF Gnats at Valley were stop-limited to 270*/sec. The Arrows had no stops and were 360*/sec..

gravity32
20th Mar 2011, 08:53
Well, that is a range of responses. Let's make the question more specific.

Say a B 757 was approaching the circuit area, still at high speed, and the pilot had a short blackout. He woke up to discover he had pushed the throttles fully forward and the plane was doing 460 knots, banked at an angle of 80 degrees. Knowing that the plane will be dropping fast, and scared that there might be a plane just below him, the pilot wants to level the wings as fast as possible. Bearing in mind that spoilers will not be involved, how long will it take to get the wings level?

It seems this is not just a question of maximum roll rate that can be achieved; some inertia must be overcome getting the roll started.

Loose rivets
20th Mar 2011, 09:39
... during my BAC111-200 conversion, our flight-controls groundschool instructor - who had worked at BAC - claimed that the roll-rate could equal that of the EE (BAC) Lightning in certain circumstances...

I just can't resist chipping in here, as nearly all my years on the 1-11 had me training on the real aircraft. We were also told the story of the roll rate from a man that had flown both types during testing. I was not sure if I believed it, but it gave a bit of street-cred.

At 20k feet or so, I was told to roll the aircraft this way and that - as hard as I liked. I think our speed would have been c 250k. It was quick, but unremarkable, the controls seeming rather heavy.

Several years went by.

I managed to get a very sick aircraft going in Seville, after desperate attempts by engineers had failed. We'd been stuck on the aircraft for 36 hours. When we came to leave, we had no crew oxygen, so headed back to the UK at low level. <10k. Plenty of fuel, 4 crew + 3 engineers.

Somewhere west of the French coast, and at cruising speed, I had a finger thrust under my nose, along with a loud cry of "Mind That!" My reaction must have been adrenalin fueled. Certainly, the ailerons were way past the angle needed to lift a spoiler, and the aircraft virtually snap-rolled. In disbelief, I stopped it with wings past the vertical, and rolled it back the long way. I know, total wimp.

It had rolled faster than anything I'd flown for aerobatics. Period.

(Fortunately, I'd spent quite a lot of time throwing small aircraft around, so managed to keep the huge toolbox stuck to the flightdeck floor during the recovery.)

I've often wondered about that tail. A lot of mass up there - hydraulic and electric motors and the like. A lot of stress in the roll.

Not a thing was ever mentioned about it, and come to think of it, I got no thanks for jerry-rigging the airplane.

gravity32
21st Mar 2011, 09:28
Wow. It seems some aircraft can roll fast.

I came across this at Aviation Week:
"Aircraft with very long wings, and in particular airplanes with engines distributed outboard along the wings, tend to have more formidable inertia than airplanes with engines located on the fuselage. The amount of fuel in the wings can also make a considerable difference in an aircraft's roll inertia, as an aircraft with fully loaded wings at the beginning of a long-range flight will have a much higher moment of inertia about the aircraft's longitudinal axis than when those tanks are empty. It takes a lot of force to begin rolling those transports. According to the FAA's Airplane Upset Recovery Training Aid, "This greater inertia must be overcome by the rolling moment to produce a roll acceleration and resulting roll angle, and the effect is a sluggish initial response."

So it seems there can be considerable variation. Specific questions:
Does the B757 deploy spoilers at high speed?
As its engines are some distance out from the body, would it be regarded as sluggish in initiating a roll?
Would the amount of fuel in the tanks make a perceptible difference to the initiation of roll?

Machinbird
21st Mar 2011, 14:43
One of the fastest rolling aircraft around is the A-4 Skyhawk at up to 720 degrees/sec. Enough roll acceleration to bang your head off the canopy if you aren't the one flying (2 seat versions). Enough roll rate to over-pressurize the wing fuel tank from centrifugal force effects and damage the wing (I've investigated some of the resulting incidents). Max roll rate only allowed for one 360 degree roll before stopping it due to roll-pitch coupling.

grounded27
22nd Mar 2011, 03:55
Lets not forget Tex Johnson and the B707. This may not have been about rate but certainly balls can be respected..

gravity32
25th Mar 2011, 14:35
Can anybody give me a figure for how long it would take in a standard Boeing757 to go from an 80 degree bank to wings level at a high speed?

sevenstrokeroll
25th Mar 2011, 15:18
27 seconds

but why?

Chris Scott
25th Mar 2011, 16:00
Strange that no 757 jockeys appear to have latched on to this thread. Never flew them myself.

But I am also curious to know why you are fixated with the 757, gravity32, and it seems I may not be the only one. :confused:

Fair question?

gravity32
25th Mar 2011, 16:38
I have been involved in arguments with people over some of the events of 9/11. They are arguing that the official account of the impact of AA77 on the Pentagon cannot be correct because they found a few witnesses who say the plane passed north of the former Citgo gas station. If it did, it could not line up with the damage trail, both outside and inside the Pentagon. They assert the damage was done using explosives, while the plane flew over the top of the Pentagon. No witnesses to the plane flying over the top have been found. These people do not seem to respond to the fact that far more people are on record that the plane hit the Pentagon.

We have radar data showing the plane aiming right at the impact damage at the Pentagon, but it does not go all the way as the plane gets too low for radar. I have done some calculations which show that if the plane curved round the Citgo gas station at the reported 530 mph, it would have to be steeply banked. It has to come out of the left bank then go into a right bank.

There is only one thing missing in my calculations: the time and distance it would take to switch bank from left to right, say 70 degrees each way, assuming maximum control wheel input was used?

bubbers44
25th Mar 2011, 16:46
My guess is 3 or 4 seconds unless you wanted to rip up the wings but what difference does it make? I always knew I could right the 757 with no problem but probably wouldn't have hacked a stopwatch. I'm sure it would do a great aileron roll. I wish I had done one in the sim. My home flight simulator does it very well but it also does a split S to a landing. I've flown in level flight inverted in the 737 real sim over LAX. It has a very good roll rate so assume the 757 is about the same.

bubbers44
25th Mar 2011, 23:16
G32, if you didn't care about tearing up the airplane a 70 left to right bank could be accomplished in around three seconds. Wonder where the airplane and all their passengers went after the event? AA587 and TWA800 investigations were both bogus in my opinion but not this one. Coverups are quite common throughout the world to get the public to believe certain things. Hiding a 757 with a bunch of passengers on board that disappeared after being in sight on descent heading for the pentagon at low altitude isn't. Blaming a copilot for aggressive rudder movements and center fuel tank explosions are easier to BS the public with. They were both BS but most of the public went along with it. Airbus and the US government were successful in pulling it off.

gravity32
26th Mar 2011, 02:38
Thanks B44. That is a good clear response. If 3 seconds is the quickest the roll could be done, this manoeuvre is out of the question as there are only about 4 seconds available for the whole thing, left turn, roll, right turn. With 3 seconds used up rolling, hardly any turn would occur.

Can anyone find a reason it could be done quicker?

bubbers44
26th Mar 2011, 12:11
The quickest would be to deploy a bit of spoilers so you have differential spoilers helping the roll rate and using full aileron but you could cause some damage to the aircraft.

gravity32
26th Mar 2011, 12:57
I didn't think spoilers could be deployed at such high speed, 460 knots. I thought they would not be needed at high speed as the ailerons would have all the authority anyone would need. I also thought they might be at risk of damage at high speed. Perhaps I am wrong about these things.

If spoilers could be used, and were used, what would be your estimate of roll rate?

bubbers44
26th Mar 2011, 14:03
Probably around 100 degrees per second with full deflection. Good luck on everything hanging together. I would expect the ailerons to take a lot more stress than the speed brakes would with full deflection.

bubbers44
26th Mar 2011, 14:25
According to a google search the flight test roll rate exceeded 60 degrees per second at what ever speed they tested it at.

gravity32
26th Mar 2011, 15:59
My Google searches have not been fruitful. Where did you find that?

barit1
26th Mar 2011, 16:40
gravity32:

The AA77 maneuvering problem is more basic than just roll rate. Why not chart the supposed course on a city map, using the greatest possible turn radii, then work it as a centrifugal force problem at 530 mph (kts I presume?). At 530 in a 2g turn, the nose just creeps around the horizon. Even if you totally neglect the time required to roll into/out of the required bank, I'll bet you need to make 4 or 5g turns to fly the required course.

gravity32
26th Mar 2011, 16:44
With half a second allowed for roll time the radius of turn is 1893 feet, the force is 9.97g, the bank angle 84.3 degrees.

It couldn't survive the g-force and if it did, nobody saw that bank!

bubbers44
26th Mar 2011, 16:59
B757 Upgrade To B767 — Tech Ops Forum | Airliners.net (http://www.airliners.net/aviation-forums/tech_ops/read.main/224945/)

I couldn't find any official reference to this post 20 and 22 info.

Jane-DoH
27th Mar 2011, 00:40
Chris Scott

"...as soon as the (control wheel) is (fully) displaced, the spoilers will rise on the downgoing wing (to 43deg)......and the spoilers on the upgoing wing will retract. In this config, maximum roll rate is about 400deg per second."

That's on par with some aerobatic aircraft...

Why would they have configured the control-system to produce such a heavy roll rate all the sudden at maximum control surface deflection? I thought the whole idea is so that it builds up in a predictable manner...

Loose Rivets

My reaction must have been adrenalin fueled. Certainly, the ailerons were way past the angle needed to lift a spoiler, and the aircraft virtually snap-rolled. In disbelief, I stopped it with wings past the vertical, and rolled it back the long way. I know, total wimp.

It had rolled faster than anything I'd flown for aerobatics. Period.

Impressive...

Machinbird

One of the fastest rolling aircraft around is the A-4 Skyhawk at up to 720 degrees/sec. Enough roll acceleration to bang your head off the canopy if you aren't the one flying (2 seat versions). Enough roll rate to over-pressurize the wing fuel tank from centrifugal force effects and damage the wing (I've investigated some of the resulting incidents).

I didn't know a plane could roll fast enough to damage itself...

Max roll rate only allowed for one 360 degree roll before stopping it due to roll-pitch coupling.

What's roll-pitch coupling?

Machinbird
27th Mar 2011, 02:31
What's roll-pitch coupling?
Envision an aircraft rolling at a high rate with some angle of attack.
The angle of attack displaces the nose above the roll axis and the tail below the roll axis. Centrifugal force from the roll tends to force these extremities away from the roll axis causing a potentially uncontrolled increase in angle of attack.

I didn't know a plane could roll fast enough to damage itself...

The A-4 wing fuel tank is a single tank spanning both wings, however if the correct conditions exist, pressure in one wing can exceed the structural strength of the rivets attaching the internal stringers to the wing skins and the stringers to the ribs. One squadron I was in had such an incident and the Blue Angels had one too. Normally it was the port wing experiencing damage. The starboard wing had the fuel dump/overpressure relief valve and was rarely damaged.
Each aircraft has different considerations, but under the right conditions you could overpressurize a wing or throw engines by generating a great enough roll rate.:uhoh:

Jane-DoH
27th Mar 2011, 02:40
Machinbird,

So you get a corkscrewing action going?

gravity32
27th Mar 2011, 02:45
It seems to me I have asked the wrong question. The term "roll rate" appears to relate to a stabilized process in which the initial inertia has been overcome.

In a plane like a B757 the wings are long, the engines are outboard and the fuel tanks go well out along the wings, so there would be a lot of inertia.

The proper question is not roll rate, but time for a roll of a specific number of degrees. Since flying at 2g is within the permitted range, which has a bank of 60 degrees, does anyone have a figure for the time to go from wings level to 60 degrees, with maximum control wheel input, in a B757?

bubbers44
27th Mar 2011, 03:10
Depending on speed probably less than a second to reach a 60 degree bank but nobody flies that way because the engines and pylons aren't built to take those forces so even test pilots don't do it. They may withstand it but nobody flies like that. Tell your conspiracy friends about the 9-11 Pentagon crash that it didn't make a 10G turn but vaporized. That is the only explanation for not seeing it depart at high speed. I wonder after the 10 G turn where they were going?

gravity32
27th Mar 2011, 04:43
There is of course no doubt the plane hit the Pentagon. There are many witnesses, including three of their star north-of-Citgo witnesses, Lagasse, Turcios and Brooks, who all said they saw the plane hit the Pentagon. Sean Boger from the Control tower at the Pentagon Heliport watched it all the way into the Pentagon. Albert Hemphill at the Navy Annex said it was to his right, and flew straight over the bridge into the Pentagon. There is not one witness to the plane flying over the Pentagon though there were hundreds of cars stuck in traffic around the area.

There is radar data from four installations all leading directly to the Pentagon impact site. Now there is also the FDR file, which has recently been fully decoded, showing the plane flying straight, at the same track angle as the radar, and descending. The last radio height is 4 feet. Add 6 feet for the offset and 16 feet for the height of the wings above the wheels and you get a height that matches the length of the chopped off light poles.

So all the evidence shows the plane hit the Pentagon. Its mass is sufficient to smash the wall. Most of it went inside. There is enough debris outside to account for the parts that were too light to penetrate. The claim the plane flew north-of-citgo is a claim based on no evidence other than a few who were mistaken about something that would not seem important to remember at the time.

The Science of 9/11| Pentagon (http://www.scienceof911.com.au/pentagon)

Machinbird
27th Mar 2011, 05:52
So you get a corkscrewing action going?

Worse than that. The aircraft could go completely belly into the wind and convert its roll momentum into yaw momentum (worst case).

gravity32
I wouldn't worry too much what a few borderline psychos have concocted. Reasoning, thinking, men can hear these stories and discard them. Those that embrace these strange theories have an emotional need. That is their problem. All you need to do is firmly state, "That is BullSh*t," to indicate you do not want to play their game.

Jane-DoH
28th Mar 2011, 02:55
Machinbird

Worse than that. The aircraft could go completely belly into the wind and convert its roll momentum into yaw momentum (worst case).

Okay... so as it would roll, centrifugal forces would rapidly drive up the AoA, which then arrests the roll and causes a gigantic sideslip?

gravity32
11th Apr 2011, 13:42
Machinbird, these guys are not psychos. They are smart operators who have figured out that they can sell DVDs by creating controversey. They do harm and should be opposed.

My revised calculations show that the plane would have to be banked at 77degrees to perform the proposed ridiculous turn with a g-force of 4.4.

This leads to an interesting question. What is the maximum bank angle that a B757 could fly at and maintain height?

The maximum legal bank is arrived at from the maximum legal load, 2.5g, about 66 degrees, but we don't want to apply this restriction. The question is really about power. At maximum power, what bank angle could it get to and maintain height, assuming it did not break up?

I presume it could be worked out knowing the max power, and the drag at various AoA, given that the AoA and bank angle must be related in a level turn.

Any takers?

Chris Scott
11th Apr 2011, 16:15
Quote from Jane-DoH:
"Quote from Chris Scott:
"...as soon as the (control wheel) is (fully) displaced, the spoilers will rise on the downgoing wing (to 43deg)......and the spoilers on the upgoing wing will retract. In this config, maximum roll rate is about 400deg per second."
"...as soon as the (control wheel) is (fully) displaced, the spoilers will rise on the downgoing wing (to 43deg)......and the spoilers on the upgoing wing will retract. In this config, maximum roll rate is about 400deg per second."
That's on par with some aerobatic aircraft...
Why would they have configured the control-system to produce such a heavy roll rate all the sudden at maximum control surface deflection? I thought the whole idea is so that it builds up in a predictable manner..."

Apologies, Jane: I completely missed your post. Did have some later misgivings re mine, though. Obviously, once the roll-spoilers on the upgoing wing have retracted, the situation is the same as if they had been retracted (as speedbrakes) in the first place.

However, I think the point my BAC 1-11 ground instructor was making may have been relating to the initial response. Due to the moment of inertia of a 30-ton aeroplane with a fairly large wingspan, the rate of increase of roll-rate is likely to be pedestrian in relation to lighter fast jets with small wingspans, like the contemporary English Electric (BAC) Lightning that he was comparing it with.

I think you have a point, except that it wouldn't happen all of a sudden on the One-Eleven. Mind you, the 200 series I first flew certainly was agile. If you look back to my post, you'll see reference to the roll-spoilers not "cracking" until a moderate amount of aileron displacement (unlike the B707). Being airline pilots, we tried not to pass that threshold if convenient, because of the slight aerodynamic rumble from the spoilers.

Regards,
Chris

barit1
12th Apr 2011, 20:15
What is the maximum bank angle that a B757 could fly at and maintain height?

It's related to specific excess power (http://www.aviation.org.uk/docs/flighttest.navair.navy.milunrestricted-FTM108/c5.pdf).

But the 757 didn't have to maintain height; it was undoubtedly using its potential energy in a shallow dive, aiding the specific excess power issue.

Nonetheless, good luck with the 4.4g. :}

gravity32
13th Apr 2011, 12:30
barit1, that is a very interesting article. Thanks.

It is clear that height and excess speed can provide power to maneuvre. Certainly the 757 had plenty of speed but very little height. The problem is it only had at the most 1 second to get its wings level from 77 degrees and pull out of the dive. It finished virtually level.

The FDR data shows it pulled up from a 5 degree descent to about 1 degree in 2 seconds and that the average force during these 2 seconds was 2g. If this absurd turn is to be believed, only 1 second would be available thus 4g lift would be required, all starting from a bank of 77 degrees. Could it do it?

gravity32
19th Sep 2011, 08:44
barit1, re your posts #26 and #39, and all those who have helped with this question,

You may be interested to see the path the plane would have flown, if it had passed north of the Citgo service station on the way to the Pentagon, as asserted by some websites. Calculation shows that the plane would be banked at 77 degrees to perform the turn at the known speed. Or it would if it could complete the roll from a left bank to a right bank in 0.5 seconds. If it needed longer than that, the bank would have been even steeper.

http://i1210.photobucket.com/albums/cc402/gravity980/Pentagon_bank_angle/70deg_achimspokstarboardwing2.png

The second image above shows a plane at about 70 degrees. Funny than none of the many witnesses mentioned this sort of bank angle. All witnesses either said the bank was slight or did not mention bank at all. Apparenly the bank angle was not thought worthy of comment. Do you think we can safely conclude the plane actually flew pretty well straight from its last radar position to the impact point?
http://s1210.photobucket.com/albums/cc402/gravity980/

skwinty
19th Sep 2011, 14:39
Hi gravity32,

What does the FDR reveal with respect to aircraft attitude?

Or is that in your opinion bogus ?

ETA: Reduce the size of the image to prevent page over run.

gravity32
19th Sep 2011, 17:55
skwinty,

I would like to show you a graph of roll and pitch for the last 30 seconds, during which full power was applied. There was a significant dive then a levelling off. Last pitch reading was -1.2 deg.

However I can't do it. I can copy the graph to the edit page but it disappears when I post.

skwinty
19th Sep 2011, 17:58
What format is the graph?

PDF?

Place the file on Photo bucket and post a link.

ChristiaanJ
19th Sep 2011, 18:02
Idem re the link to photobucket

CJ

gravity32
19th Sep 2011, 18:17
The file is in Excel. I can copy it to Word and then to a pdf. However photobucket is only interested in images like jpg.

Why do the posting rules say I can't post attachments?

So I printed it, scanned it, sent to photobucket. There must be a better way. You can see there was a significant dive during this 30 seconds, and a pull up to almost level at the end, -1.2 deg. Re your question about the FDR file, I can find no reason to suspect that it has been tampered with. Everything seems to correlate. It is clear that the control is rather erratic, suggestive of inexperienced pilot.

http://i1210.photobucket.com/albums/cc402/gravity980/Rollandpitch_last30s-1.jpg

skwinty
19th Sep 2011, 19:27
At first glance, it is clear that the roll was mostly positive and the pitch negative, heading towards level flight to impact the building.

Seems consistent with a large airliner flying at nearly 500 knots.
I am not an expert in this field so YMMV.:ok:

gravity32
20th Sep 2011, 05:27
Yes the bank was positve, but erratic, as the plane did its circling descent, until about 20 seconds from impact, when the plane then flew straight to impact.

The bump in the pitch graph at 5 seconds suggests the pilot had caught sight of the VDOT antenna tower and eased the control column to ensure he cleared it, then pushed forward again, overdoing it and having to pull back to avoid hitting the ground before impact.

The maximum bank of 6 degrees, very brief, during the last few seconds, rules out any possible deviation round the service station, if the FDR data is to be believed, and I see no reason to doubt it.

fdr
20th Sep 2011, 08:36
400degrees/sec? not even close. that has an extra "0" in it... and is still wrong for the B767 or B757.

at high speeds, exceeding VMo, the wing "such as" on the B757 can result in roll reversal occurring, (have seen 2 separate sets of data on similar configurations where this has occurred).

A4 roll rate is noted fairly accurately, it will mess with the side of your helmet.

For jet transports at high speed, the flightpath vector is not going to change substantially without pulling extreme g loads, and that will pretty much mess up the wreckage location.

A320Slave
21st Sep 2011, 05:10
For those who wish to learn more regarding this topic and "gravity32".....

Frank Legge Begging For Peer Reviewers For Pentagon Paper - Pilots For 9/11 Truth Forum (http://pilotsfor911truth.org/forum/index.php?s=&showtopic=21569&view=findpost&p=10800866)

and here....

Frank Legge Begging For Peer Reviewers For Pentagon Paper - Pilots For 9/11 Truth Forum (http://pilotsfor911truth.org/forum/index.php?s=&showtopic=21569&view=findpost&p=10801255)

And understand that "gravity32" hasn't a clue with anything related to aeronautical knowledge.

A320Slave
21st Sep 2011, 05:13
at high speeds, exceeding VMo, the wing "such as" on the B757 can result in roll reversal occurring, Exactly.

It is also covered here....

Full Film - 9/11: World Trade Center Attack - Pilots For 9/11 Truth Forum (http://pilotsfor911truth.org/forum/index.php?showtopic=19732)

Unfortunately, a chemist named Frank Legge is trying as hard as he can to discredit seasoned pilots. Unfortunately for Frank Legge, he will not be able to distort aerodynamics or the truth.

CJ, do you still think that a radalt can accurately measure Absolute Altitude at anything less that 330 fps descent rate?

gravity32
22nd Sep 2011, 08:53
This thread started with a discussion of roll rate for a 757. Various opinions were expressed. Eventually it became clear that roll rate was not the right question for the case at hand. Roll rate describes a continuous process. What we needed to know was the initial behaviour of the plane when a full control input was applied, taking into account the inertia of the heavy plane. It seemed this would be hard to discover.

The calculation at the beginning of this page showed that a bank of 77 degrees would be required if the plane passed north of the Citgo service station. That calculation was based on an assumption that the roll from left to right could be completed in 0.5 seconds.

The required information is apparently now available from the FDR of UA 93. We see that full application of the control wheel produces only about 30 degrees of roll in the first second.
Volo 93 - Animazione NTSB (sintesi) 4a parte - YouTube

Can we can conclude from this that the calculation shown at the beginning of this page, that a bank of 77 degrees would be required, with a wing loading between 4 and 5 g, is a gross underestimation? Is so, the plane simply could not have performed the maneuvre required to pass north of the Citgo service station and still arrive in the vicinity of the impact point.

A320Slave
22nd Sep 2011, 15:19
9/11: The North Flight Path (official Release), Aerodynamically Possible - Witness Compatible (http://pilotsfor911truth.org/forum/index.php?showtopic=15854)

_b9kbiN8SfE

The North Approach, Technical Supplement to "9/11: The North Flight Path" (http://pilotsfor911truth.org/forum/index.php?showtopic=15930)

"gravity32", you may also want to look up the definition of Maneuvering speed with respect to the full and abrupt control wheel movement as seen in the UA93 video you posted above.

gravity32
22nd Sep 2011, 16:44
A320,
Of course, if you slow the plane down and ignore the direction the plane was flying prior to the alleged deviation round the Citgo service station, you can get it to perform a viable curve. However even then the 300 knot curve has a bank of 45 degrees. No witness mentioned a bank anywhere near that large. And those witnesses that did mention a bank indicated the bank did not commence until the last second or two, greatly reducing its effect.

Here is an image showing the prior flight path as established by four independent radar facilities.

The track they show is heading straight for the Pentagon impact point. The last radar position is not far from the Sheraton Hotel. If you start your deviation there you need a left turn then a right turn. None of the diagrams in the above video show the left turn. Many witnesses spoke of the engines "spooling up" and "full throttle" so it is hard to see how the plane could have slowed down. The FDR file shows the plane accelerated and flew straight in this section. The radar positions confirm the speed shown in the FDR file.

Certainly you can draw a curve around the service station but do you not agree that you have to ignore a lot of evidence to do so?

A320Slave
22nd Sep 2011, 17:09
However even then the 300 knot curve has a bank of 45 degrees.You need to check it again.

http://i53.tinypic.com/9kzdya.jpg

These are the various paths based on returns from local radar.

http://i52.tinypic.com/28lrwn7.jpg

FlickCabin.com - AA77TNi1_img_extZoomOut.jpg (http://flickcabin.com/public/view/full/19148)

You have cherry picked data to suit your bias. When you average the above flight paths based on radar, it lends itself to a northern approach, which is incompatible with the physical damage.

Also, it appears you trust data provided by government agencies and turn a blind eye and ear to witnesses cherry picking those to suit your bias while also misrepresenting what those witnesses have said, at the same time you distrust the data provided by the NIST and you feel the WTC was destroyed by controlled demolition based on witnesses describing explosions and what some have described as paint chips which you feel are some super military grade nano-thermate.

gravity32
24th Sep 2011, 03:28
A320Slave, would you mind reducing the size of your image to avoid upsetting the text?

Regarding the course of the plane, let us see how it looks if we take into account the best evidence we have about bank angle. Hemphill says the plane was always on his right and went straight to impact with the Pentagon. See his line of sight in the image below. Morin says he stepped out from between the wings of the Navy Annex and watched the plane descending, going parallel with the Annex, and therefore straight. Darrell Stafford and Darius Prather show the plane was wings level going over the roof of the Annex. See their illustrations below.
http://i1210.photobucket.com/albums/cc402/gravity980/Pentagon_bank_angle/Stafford_flatonroof.jpg
Stafford: "Flat on top of the roof" [of the Navy Annex]

http://i1210.photobucket.com/albums/cc402/gravity980/Pentagon_bank_angle/Prather_flatonroof.jpg
Prather: "This is the Navy Annex.." [His left hand]

Clearly we cannot start the turn until the plane has cleared the Navy Annex. You say we should not trust the radar track, so let us move the track northward to ease the turn as much as possible. The plane was viewed through the southern windows of the Sheraton Hotel and Paik's workshop, so we cannot place the track further north than their positions. The long thin yellow line is the track as determined by radar. The green line is the track shifted north. The turn, shown in red, commences at the edge of the annex. Half a second is allowed for rolling from a left to a right bank, which is impossibly short, thus easing the turn further.

http://i1210.photobucket.com/albums/cc402/gravity980/Pentagon_bank_angle/Paik_Morin_70.jpg

What do we find? The radius of turn is 1599 feet. The average air speed according to the FDR for the last four seconds was 480 knots. This gives a bank angle of 85.5 degrees with a wing load of 12.8g.

Clearly that won't work for you. We will have to ignore a bit more evidence. We will ignore the speed and acceleration of the plane as determined by radar:

Witnesses say the plane was "spooling up", "full throttle", "powered descent" and " the noise was absolutely deafening". That seems to indicate the plane was speeding up, as shown by radar and in the FDR file, where we see the throttles pushed fully forward for the last 30 seconds. But let us ignore all that and see how slow the plane would have to go to achieve a bank of say 30 degrees. We find it is 102 knots.

But it is worse than that. Prather makes it clear the plane travelled some distance past the Annex and descended before the turn commenced.

http://i1210.photobucket.com/albums/cc402/gravity980/Pentagon_bank_angle/Prather_flatoffroof.jpg
Prather: "It dropped down a little bit."

http://i1210.photobucket.com/albums/cc402/gravity980/Pentagon_bank_angle/Prather_banked.jpg
Prather: "and then it started angling."

If we take the delayed turn into account, the g-force and bank, already impossible, will become astronomical. I think you would have preferred the previous more conservative analysis where we assumed the plane started to deviate at the last radar position. That gave a bank of 77 degrees and a load of 4.8g.

It is clear Stafford and Prather misjudged the position of the plane and thought it was closer than it was. They were not really in a good position to judge the distance, being near the cemetery, but the angle of bank near the Annex would have been very clear and easy to get right. Hemphill was the one who was in the best position to see the alignment of the track and he asserted that it was always on his right and that "it didn't turn left, it didn't turn right". He also mentioned ground effect, indicating he perceived the plane as very low and wings level. He made no mention of bank at all. Surely a bank of 77 degrees, as in the first calculation above, would have been very clear to him but he made no mention of bank.

Many witnesses described the approach of the plane to the Pentagon. None mentioned a steep bank. Few mentioned the bank at all and those that did said it was slight.

Is there any conclusion possible other than that the plane flew pretty well straight from somewhere near the Annex to the impact point?

A320Slave
24th Sep 2011, 05:26
These are the tracks as drawn by the witnesses.

http://i14.photobucket.com/albums/a327/lytetrip/Pentagon/witness%20flight%20paths/ancpathcomposite.jpg

These are the witnesses themselves.

http://i14.photobucket.com/albums/a327/lytetrip/Pentagon/gifs/ancgif2.gif

Here are more witnesses which have stated they "bet their life" on the flight path, which includes two pentagon police officers that you have said are either lying or mistaken.

http://i14.photobucket.com/albums/a327/lytetrip/Pentagon/gifs/citgoguys2.gif

More witnesses drew their flight paths as depicted here in orange.

http://i14.photobucket.com/albums/a327/lytetrip/Pentagon/flight%20path/AllGroupsMapV3.jpg

Here is another flight path animation which corresponds to the witness flight paths depicted above.

DQsyt_7c1H8&

All of the above are corroborated.

"gravity32", your flight path is cherry picked to suit your bias and is intellectually dishonest when taking into account all the information.. A bias which has an astonishing double standard considering you feel the WTC was destroyed by controlled demolition using some type of classified super duper military grade "nano-thermate".

The video I posted in post 53 (http://www.pprune.org/tech-log/446123-roll-rate-3.html#post6712740) is the type of analysis which is intellectually honest when taking into account all of the information. Many paths are aerodynamically possible and witness compatible. I suppose we will have to agree to disagree once again. Let us know when you will get one pilot to sign their name to your papers. So far, it appears you are 0 for 3. 0 for 11 if we count your revisions.

gravity32
24th Sep 2011, 06:38
A320Slave,

For the plane to pass near the Navy Annex with wings level it would have to get into a steep bank to deviate round the Citgo service station. Do you honestly think Stafford and Prather looked at the plane banking at about 80 degrees and didn't notice it was banking?

A320Slave
24th Sep 2011, 06:55
Forgot to add this.

For those interested in listening to the interviews filmed on location of the above witnesses, here is the video.

j5FhQc-LJ-o

gravity32
24th Sep 2011, 07:45
For those interested in what really constitutes corroboration and cherry picking, here is a list:

Over a hundred people are on record as saying they saw the plane hit the Pentagon.
About 13 people said they thought the plane flew north of the Citgo service station.
Of the 13 who said it flew north of Citgo, all those who were in a position to see the Pentagon said it hit the Pentagon.
Hundreds of people were in traffic jams around the Pentagon and would have seen a plane fly over but nobody has said they saw a plane fly over.

A320 and friends insist that because 13 corroborate one another it must be true. What about the 100 plus who corroborate impact?

So much for corroboration.

If you look at the full videos of the people interviewed who support the north path you will find some interesting things. For instance Sgt LaGasse demonstrates with his hands that the plane went in at an angle and says "When the plane hit it just kinda disappeared." He indicated that his memory for details might be flawed but his memory of impact was not. "There is only one thing that is irrefutable .... the fact is American Airlines plane went from here into the building. You can pick apart everything else."

And Turcios. He said the plane was to the north but when asked if he saw the plane fly over he looked surprised and said "Fly over? No the only thing I saw was .... on a direct line to the Pentagon. It collided."

And Chad Brooks said he watched the plane "awfully low .. just go nose dive into the Pentagon ... full throttle .. clip the lamp pole ... just the sheer impact ... it just literaly disintegrated the plane."

So they didn't just cherry pick the witnesses who were prepared to say the plane passed north of Citgo, and avoid interviewing all those who saw the impact, they also cherry picked the parts of the interview that suited their story.

So much for cherry picking.

Pugilistic Animus
26th Sep 2011, 20:34
An airliner with a MTOW of 255000lbs flying as fast as possible can't possibly do any damage:rolleyes:
even though a Cherokee can destroy a seven story steel building and a Cirrus can wipe out a whole floor of apartments:cool:Google Images (http://www.google.com/imgres?q=texas+tax+airplane+crash&um=1&hl=en&client=firefox-a&sa=N&rls=org.mozilla:en-US:official&biw=1360&bih=578&tbm=isch&tbnid=ExZE8b-Q1WY8EM:&imgrefurl=http://www.webtechgeek.com/wp/news/2010/02/20/texas-plane-crash-heres-an-explanation-of-the-tax-law.html&docid=GmaHwFlrc9K2HM&itg=1&w=399&h=266&ei=D9KATuGiCKHw0gGb3M0W&zoom=1&iact=hc&vpx=158&vpy=145&dur=14889&hovh=183&hovw=275&tx=95&ty=46&page=1&tbnh=114&tbnw=150&start=0&ndsp=21&ved=1t:429,r:0,s:0) Google Images (http://www.google.com/imgres?q=corey+lidel+crash&um=1&hl=en&client=firefox-a&sa=N&rls=org.mozilla:en-US:official&biw=1360&bih=578&tbm=isch&tbnid=Uqx1aauarwwiUM:&imgrefurl=http://articles.nydailynews.com/2011-02-12/local/28612057_1&docid=N-Og13J34YwFzM&w=450&h=339&ei=FNWATt7GHIba0QHhpJTnDw&zoom=1&iact=hc&vpx=592&vpy=265&dur=355&hovh=195&hovw=259&tx=103&ty=91&page=3&tbnh=164&tbnw=225&start=22&ndsp=10&ved=1t:429,r:7,s:22)
I have more patience with Ssg than I have with these 9-11 clowns at least I find Ssg amusing...these stupid theories are insulting to the relatives of those who died and absolutely ridiculous to propose nano-thermite/controlled demolitions/missiles what complete :mad:

:*

gravity32
27th Sep 2011, 02:42
They don't say there was no damage. They say the damage was done using explosives to create an illusion of plane impact. Two planes had already been flown into buildings, so why not a third? It makes no sense.

Why these people want to create a myth is a mystery.

Pugilistic Animus
27th Sep 2011, 23:44
I guess I'm mixing it up with what these idiots are saying about the WTC attacks
i.e that a plane hit-as it is undeniable- but that the damage done was a subsequent controlled demolition-my point is that these freaks should just be ignored:)

A320Slave
29th Sep 2011, 06:32
but that the damage done was a subsequent controlled demolition-my point is that these freaks should just be ignoredhttp://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/smile.gifFunny you should bring this up, PA.

"gravity32" did you say the following?"Regarding explosives, there are several lines of evidence that the buildings were brought down by controlled demolition.....

.....no-one is suggesting that only thermite was used in the demolition. It is reasonable to suggest that thermite would have been used to weaken the main structures then high explosives used to finish it off in precisely timed manner required." - gravity32, 911studies :: View topic - 9/11 - Evidence for Controlled Demolition, by Frank Legge (http://www.atfreeforum.com/911studies/viewtopic.php?p=104&mforum=911studies#104)

See more here (http://pilotsfor911truth.org/forum/index.php?s=&showtopic=21569&view=findpost&p=10801255) and here (http://pilotsfor911truth.org/forum/index.php?s=&showtopic=21569&view=findpost&p=10801474) with respect to this discussion and "gravity32".

.

gravity32
29th Sep 2011, 08:42
A320Slave,

You are clutching at straws. Can you prove the plane did not hit the Pentagon?

I don't think so.

A320Slave
29th Sep 2011, 08:47
Can you prove that the WTC did not collapse by gravity, fires and structural damage?

Your argument is a logical fallacy.. It is known as an Argument from Ignorance (http://en.wikipedia.org/wiki/Argument_from_ignorance).

What is harder, planting enough high explosives and thermite in 3 WTC buildings? Or manipulating data?

Why do you trust the data provided by government agencies with regard to the Pentagon, yet feel the WTC was destroyed by controlled demolition?

Again, your double standard is astounding.

gravity32
29th Sep 2011, 09:08
I trust the witnesses to impact, and the witnesses to the plane having only a slight bank, making the north path impossible. You must be joking, right? Do you get a kick out of this?

The radar and the FDR happen to agree with the witnesses, but, as you say, somebody might have fiddled with the records. Lucky we have so many witnesses to support the data, and not one witness to a flyover!

A320Slave
29th Sep 2011, 09:25
Don't you ever get tired of going in circles "gravity32"?

http://www.pprune.org/tech-log/446123-roll-rate-3.html#post6715949

http://www.pprune.org/tech-log/446123-roll-rate-3.html#post6715999

I enjoy this diagram as well. It reflects the data point you are so willing to support, yet fail to get the support of any real and verified pilot (http://pilotsfor911truth.org/forum/index.php?s=&showtopic=21569&view=findpost&p=10801474).

http://i47.photobucket.com/albums/f178/myphotos1960/Legge_V-G_Diagram.jpg

Apparently "gravity32", you are the only one getting a "kick out of this" as you continue to dig your hole deeper and deeper losing support along the way, while Pilots For 9/11 Truth continue to grow (http://pilotsfor911truth.org/forum/index.php?showtopic=21644).

gravity32
29th Sep 2011, 12:07
A graph with no numbers on the x axis does not do much.

Have you forgotten this image of an honest witness?

http://www.pprune.org/%5BIMG%5Dhttp://i1210.photobucket.com/albums/cc402/gravity980/Pentagon_bank_angle/Stafford_flatonroof.jpg%5B/IMG%5Dhttp://i1210.photobucket.com/albums/cc402/gravity980/Pentagon_bank_angle/Stafford_flatonroof.jpg

No bank over the Annex! Therefore the sharply curved north path is impossible - that idea has to be abandoned.

There is an abundance of witnesses to impact via a straight path so any logical person would accept that the plane did hit. Therefore we can conclude that the plane had enough safety margin to survive the very brief period after it went over its rated speed. Do you honestly believe the plane couldn't accelerate past its rated speed for 15 seconds without breaking up? It is called fatigue failure - it takes time.

A320Slave
29th Sep 2011, 12:15
A graph with no numbers on the x axis does not do much.

Numbers are on the x-axis. You just cannot determine those numbers because you don't understand V-speeds nor do you have any aeronautical knowledge.

Now look in the lower left hand corner of this graphic.

http://i14.photobucket.com/albums/a327/lytetrip/Pentagon/gifs/ancgif2.gif

Round and round we go "gravity32".

Again, instead of just arguing in circles, I will just agree to disagree. It's pointless to argue with you, especially considering the fact you have no training whatsoever in aviation nor any support from a verified pilot. This is like arguing with a 15 year old on how to drive a car.

Let us know when you will get one verified pilot to support your claims. So far, you fail. (http://pilotsfor911truth.org/forum/index.php?s=&showtopic=21569&view=findpost&p=10801474)

Matter of fact, pilots such as PA above think people like you are a "freak". Good luck!

By the way "gravity32", since you have considered and suggest highly classified military grade super duper nano-thermate planted in the publicly occupied WTC, have you considered the same standard for classified aircraft technology? Such as Vectored Thrust? What does that do to your calculations? Don't bother to answer as we already know you prefer the double standard.

gravity32
29th Sep 2011, 13:37
Does Stafford's bank angle look like 85 degrees? The plane can't make the turn without it. And it can't make the turn with it either, as it produces a load of 12g.

To get round the curve at Stafford's angle of about 30 degrees would require slowing the plane to about 100 knots. That won't fly either.

If you can't see that Stafford and Prather, with their very clear indication of the plane flying wings level till past the Annex, totally destroys your theory, then there is certainly no hope for this discussion. There are many other witnesses but none thought the bank sufficient to be worthy of particular comment. Perhaps it was only 6 degrees as in the FDR file. Many witnesses mentioned the plane spooling up, full throttle. Perhaps it was really going fast and accelerating as in the FDR file and as shown by radar.

As you are determined to go against so much evidence-based science it is clear that we must agree to disagree, as you said above.