Attack on the Pentagon: the facade of the footprints

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New images of the footprints of the facade of the Pentagon are available here

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After a long time since my first article in which I tried to make a reconstruction of the impact of an aircraft into the Pentagon, I go back to talk about this topic because I think a few points that should be explored in the first article were only hinted at or even ignored.

The time is ripe to resume these issues and to formulate some hypotheses entirely personal that I believe may be of some public interest.

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A first point which I would like to mention is on the plane geometric configuration which impacted the Pentagon.

As said, the plane has impacted the facade of the building with an angle of inclination with respect to the normal to the façade of about 42 °, with the right wing higher than the left.

I also remember that the right engine would have impacted the generator, causing it to rotate on itself, to the effect of a violent collision, in a clockwise direction and leaving on it of damage dimensionally compatible with the engine and the profile of an actuator of the flaps.

An image of a passage at high speed and low altitude of a twin-engine line allows us to appreciate the magnitude of the elastic deformation phenomenon of the wings.

If instead we consider in the following, relating to a low altitude and high speed passage of an Airbus, the comparison of the yellow rectangle mask, it is possible to appreciate the dynamic behavior of the wings, in particular of the external portions: the inflection towards the 'brings the highest wingtip to a considerable height from the ground than the rest of the static position configuration.

Never as in this case a picture is worth a thousand words:

It 'is therefore clear that it is not possible regardless of this phenomenon in the analysis of the impact of AA77 at the Pentagon, since even minimal height differences may constitute the calibration elements of the type "go / no go" to validate or less hypothetical reconstruction .

I think it's really important to focus on the deformation upwards of the outer third of the wings.

Recall also that the wings of a scheduled are largely occupied by the wing-mounted fuel tanks, for which reason the deformation is even more interesting.

This is the configuration of the fuel tanks of a Boeing 757-200, the plane of Flight 77.

Of the three tanks, the central one is the first to be emptied, for which, at the moment of impact, the wing tanks were still practically full of fuel.

This is the reason why the Purdue University considered fundamental to study the role of the liquid (whose main characteristic is to be incompressible and transmit in all directions, with the same intensity, the force exerted at a point) in the analysis of damage the supporting structure of the Pentagon, advancing the hypothesis, then confirmed by modeling and empirical evidence, that the effect of actions by the wings breakthrough was mainly caused by the action of hydrodynamic fluid that, in addition to break through the front and produce the devastating effects inside the building, he would also have resulted in the disintegration of the wing and the right wing detached from the fuselage at the first impact.

This destructuring wing justify the absence of a continuous trace of damage on the facade of the building between the point of impact / input of the fuselage and the area to the right of it, where the effects of impact of the central portion are evident dell ' wing.

And 'my personal opinion that at impact the right engine against the generator, the engine has exploded, the rotor is broken and has generated a trail of debris made up of parts of stadiums equipped with high sectional density and living force by virtue the rapid rotation which animated and speed of the plane.

These scrap would then continued their run according to certain trajectories from vector composition of forces resulting from the impact and inertia, going to violently hit the outside of the Pentagon at higher altitudes than the point of impact of the fuselage.

From a strictly operative point of view, the right engine aircraft would then hit the front in an area in which it actually sees the break-through of a wall, but the extent of damage would have been lower than that caused by the left engine due to the damage already suffered by the right engine in the collision against the generator and its immediate explosion.

In particular, looking at the outside of the Pentagon on the right side of the point of impact:

I believe that the damage to the fourth floor (American name), can be explained as the effect of the impact of the right engine turbine rotor, detached from the rest of the engine.

Looking at the details of the damage close together, you can see how this "svirgolata" has shape and geometric and physical characteristics compatible with the impact of a piece of high density and resiliency, which hit the facade with a limited surface area (such as the edge of a plate) while it was in rapid rotation around an axis of symmetry.

The composition of the motion of rotation and the violent projection against facade would have generated the inverted U shape.

This profile, in my personal hypothesis, would be due to the contact dynamics: the top of the contact is produced the ascending portion of the curve to the right, all'impuntatura you create the most damage area (curved portion), which determines the change of inclination of the axis of rotation, and then, output from the contact, the descending of the left curved portion, most inclined.

To my knowledge, there are currently no other assumptions made by anyone on the generation of that damage from such a particular form, to explain adequately the specific conformation of the damage, with a composition field, a peak of corruption at the top and a path Release of an object that has not been destroyed against the same side, but still retains enough energy to leave traces of his passage as he walked away from the impact point.

And 'interesting to note that such damage is in fact also present on the first pillar to the right of the image, at the same altitude.

If one observes the image of the facade of the Pentagon, it is seen that similar traces are also present in the part to the left of the impact point. .

If we assume that the impact profile Bo757 is that indicated in the following figure, in accordance with the physical evidence at the scene of the crime, in green are shown the positions of the plane's engines in flight and in red the "svirgolate" on the facade Pentagon:

The conclusion that can be drawn is that this damage, similar in type, could then be traced back to the impact of multiple rotating parts which have become detached from the respective left and right engines for the impacts suffered by enginesbefore impact against the façade .

If the right engine has certainly had an impact against the generator, the left has driven onto the lower boundary wall of the access area on the ground and against the metal doors in the closing down of metal stairs to the underground rooms of the Pentagon . .

The image below shows the outside of the front rotor of a turbine, which may have been responsible for the subject of one of the famous "svirgolate".

This part of the engine, in this famous images, is in fact placed on the outside of the Pentagon facade and in proximity to it can be noticed scrap composite material (in the yellow circle), which recall the rear part, of smaller diameter, of the the engine nacelle.

The gondola of the Bo757 engine is in fact made ​​of composite material , an aluminum honeycomb and graphite reinforced with Kevlar.

The use of composite materials is particularly interesting for Bo757 and assess their importance in aircraft construction can help us understand why the visas wreckage at the Pentagon are small or may even seem absent an initial summary examination.

In fact the debris are present in large numbers, as you can see from close-up pictures of the heliport area.

In the pie chart below, Boeing source, like all the images published on the use of composite materials in Bo757, it shows the percentage of the different materials that make up the plane as it comes off the production line:

The use of these composite materials has enabled a considerable weight saving compared to the traditional construction techniques:

The distribution of the components in the composite material is as follows:

For some of these components are available dimensional detail, which I reproduce as additional information: .

• the cowling of the flaps, made of a Kevlar hybrid composite reinforced with graphite fibers;

• the rudder (the vertically movable part, called in English rudder ), entirely built with the use of epoxy resins reinforced with graphite;

The composite materials are characterized by lightness and good erosion resistance, while have no significant mechanical characteristics for shock resistance.

Clarified these aspects, which has long wanted organically exhibit, I believe the time has come to analyze an issue that is close to my heart.

This topic is now invoked by those who support the "alternative" theories as evidence that the Pentagon has not crashed a Boeing 757, and covers the footprint of the vertical stabilizer impact, what we normally call the aircraft rudder or drift.

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. Footprint impact of the vertical stabilizer of the Boeing 757

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The following image, found on the network, provides an idea footprint of the vertical stabilizer of the Boeing 757 in comparison to the size of the Pentagon's facade.

The upper point of the stabilizer is to be located at the height of the lower part of the windows of the fourth floor (American notation, in Italy would be the third floor).

As said, very often it is placed provocatively demand to show where is the damage produced by this part of the airplane, seen that the facade of the building, in the vertical portion overlying the inlet opening of the fuselage, has no apparent signs of impact.

The well-known conspiracy Killtown poses, me recently, the big question during a discussion on the Loose Change forum.

So I decided to address this issue and leave it to you to judge the validity of what I am going to exhibit.

To tackle the analysis of the impact traces, you must understand how it is that the vertical stabilizer and rudder of a Boeing 757.

As I mentioned, the rudder , that is the true and right rudder (vertical moving part), is made ​​entirely of composite material (graphite-epoxy materials ) and has no mechanical characteristics that can produce damage to impacting against a stone structure as the one forming the outer part of the facade of the Pentagon.

The vertical stabilizer (the fixed part) is instead formed by a supporting structure formed by a central girder and by connecting and stiffening elements, which support the outer coating consists of light alloy panels.

In the scheme below, which I colored to better show the components, the truss in question is that blue.

Wanting very simplified, the structure of the vertical stabilizer is similar to that of a wing, vertically placed, perfectly symmetrical on the two sides.

The vertical stabilizer of Bo757 is therefore an essentially hollow element, constituted by a small light alloy central structure covered in aluminum alloy panels.

This vertical fin is held in place by the force elements which, in their turn, are connected to points of resistance bound to the covering layer of dell'impennaggio horizontal stiffening of the tail.

In these photographs, in which they were removed some of outer covering panels, one can appreciate the interior of the vertical stabilizer of a Boeing 737, such as a structural construction to that of the largest Boeing 757.

In my opinion these are really interesting other images rather unusual and rare to come by, showing the work of destruction of a Boeing 757.

In the first we see the removal of the entire vertical stabilizer and the typical break that is created in the vicinity of the fuselage when the vertical fin is subjected to a collision or to a strong lateral bending stress.

In the second instead it is placed in evidence the hardening off complex of the horizontal stabilizer (fallen to the ground following the cutting of the fuselage), normally impossible to see each other because enclosed in the inner part of the tail of the fuselage.

Inside the vertical stabilizer are placed the three actuators which control the movement of the rudder (are the three colored red elements that you can see in the diagram above, positioned in the lower half of the vertical fin). These actuators are the only elements to be made of heavy metals and have a high sectional density: in case of high intensity impact, these elements tend to detach themselves and in their motion from the inside contribute to the demolition of the resistant structure. Having a better idea about how you did the vertical stabilizer, you must now assess the impact dynamics to understand where to go to look for the traces possibly left by the vertical stabilizer.

The aircraft hit the building coming from an inclined path, in the horizontal plane from right to left, and in the vertical plane with the right wing higher than the left.

In the vertical plane the stabilizer wheel so counterclockwise, while in the horizontal plane the composition of the motion of objects that impact in subsequent times entails a further small left shift.

For this reason it is entirely wrong search for damage on the vertical of the point of impact of the fuselage.

It 'important to highlight however that the contact takes place between the facade and the right wall of the vertical stabilizer, for which the vertical fin is hit in his area less resistant to impact and, at the same time, in a manner such as to cause an intolerable decline accompanied by progress towards the facade.

In practice, it creates a progressive rubbing, rather than a real impact, all in thousandths of a second.

This dynamic implies that the damage on the facade can not be that the surface friction, due to the disintegration of light alloy and composite parts, mixed with a very limited area of ​​greatest damage zones created by the impact of the actuators and of the elements of greatest resistance.

then we should not forget that the entry of the fuselage in the palace, with the creation of a forum in which the fuselage was completely stuck to the tail, has created a guide (a kind of funnel, to put in much more earth ground), in which the upper edge of the hole has practically destroyed all that, progressively with the penetration / destructuring of the fuselage, came to impact (also in virtue of the inclination of the plane trajectory in the vertical plane).

In this mechanism a fundamental role is due to the slab between the first and the second floor (American notation).

So the vertical drift has impacted so as to create a possible track which, with respect to the point of impact, must:

• originate at the point of impact of the fuselage;
• have trends straight or slightly curved, with a greater curvature to the farthest section from the point of origin;
• It is rotated counterclockwise on the facade.

Let us see the image of the façade before its collapse, which occurred about forty minutes after the impact.

On this picture we can identify two precise points of reference, which I identify in the windows marked with numbers 1 and 2. The window 1 is placed on the fourth floor of the Pentagon, the window 2 on the third floor (again using American notation).

The point of impact is hidden by the jet of the hydrant, and these windows, with respect to the point of impact, are to the left.

Observing magnification, you see that the area bounded by yellow lines, are damages which together meet the three conditions listed above, ie damages arranged on a substantially straight track, which originates at the point of impact and rotated with respect to it counterclockwise.

Moreover, the damages are present with such characteristics only in that area, since the outside of the yellow lines are not seen impact damage (the oblique fractures of the coating are not due to impacts, but the vertical movement of the facade, as easily verifiable observing the cornice of the facade zone in the vicinity of the joint of building expansion).

It 'my opinion that one identified is the trace of the vertical stabilizer and the observation of the particular impact of damages from the wall (do not consider transparent surfaces, which also could tell us something ...) of the two windows confirms me in the deduction.

The height of the window from the ground 1 places it in the affected area from the upper part of the scrap derives, structurally much less robust, while the intermediate zone and, above all, the window 2 fall within the area directly affected by impacts of greater importance.

The window 1 has the transparent surfaces intact, with damage caused by thermal effect, is obviously broken the left edge, while the right is completely free of damage.

The damage can not be highlighted that were produced by an impact from the outside towards the inside of the building.

The window 2 is damaged on the outside right edge, where a wide shoulder area is missing, transparent surfaces seem totally absent, and above all, the damage has clearly been inflicted from the outside in and from right to left.

In summary, it is not true that there is no damage reported to the presence of the vertical stabilizer, but these are present and have specific characteristics that make it very difficult to attribute to other types of their origin.

In my personal opinion, I think I have provided sufficient evidence to support the conclusion that has been demonstrated the inconsistency of another "pseudo-trial" conspiracy, that the Pentagon was not hit by a Bo757 because there are traces of ' impact of vertical stems.

In the image below, composed of three images taken from three different photographs of departure, which include the same area, I summarize my guess about this track.

The quality of the photographic material available does not allow to make other observations that have a sufficient degree of reliability, but the presence of a net chromatic variation of the surface of the façade in coincidence of the area identified is another factor to be deepened, in the case images become available of greater definition.

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Note:

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Thanks for your kind cooperation on Professor Leonardo Lecce , professor of Aeronautical Structures, Director since November 2000 the Department of Aeronautical Engineering of the University of Naples "Federico II", and the engineer Fabrizio Nicolosi , a researcher at the same Department .

Obviously, what I write is only my thinking and do not necessarily reflect the opinion of the persons named.