Abstract: A joint for connecting a center wing box to a bulkhead of an aircraft. The joint includes a flex angle member with a first section shaped to abut against and be connected to the center wing box, a second section shaped to abut against and be connected to a first side of the deck of the bulkhead, and an intermediate rounded corner positioned between the first and second sections. First support members are attached to the center wing box at first pins and support a first side of the second section of the flex angle member. Second support members are attached to the web of the bulkhead at second pins and support a second side of the second section of the flex angle member. The first support members are positioned on a first side of the deck of the bulkhead and the second support members are positioned on an opposing second side of the deck.

Abstract: An assembly integrates an aft wing spar root fitting to an aircraft fuselage when joining the aircraft wing to the aircraft body. The assembly provides structural strength to the connection between the aircraft wing and the aircraft body, provides corrosion prevention and provides improved inspection capabilities and repair capabilities to the aircraft wing and aircraft body connection.

Abstract: Provided is an inlet bulkhead for large diameter aircraft engines. The inlet bulkhead, in certain examples, includes an annular body having an outer flange, an inner flange, and a web having a first side and an opposing second side. The web extends from the outer flange to the inner flange. The bulkhead also includes at least one annular stiffener disposed on the first side, and multiple radial stiffeners disposed on the first side, each of which extend from the outer flange to the inner flange. The annular and radial stiffeners may be integrally formed with the web.

Abstract: Aspects related to aircraft for commercial air travel and methods of manufacture. An aircraft includes a blended wing body, a single deck located within the blended wing body, wherein the single deck additionally includes a passenger compartment located in a lateral middle portion of the blended wing body and at least a cargo store located laterally outside the passenger compartment, and a landing gear, wherein the landing gear includes at least a nose gear located substantially forward of the single deck and at least a main gear located substantially aft of the single deck, wherein one or more of the at least a nose gear and the at least a main gear occupies a gear housing that overlaps with a plane coincident with at least a portion of the single deck.

Abstract: Embodiments for hybrid pressure deck of an aircraft. One embodiment is a pressure deck disposed over a main gear wheel well of an aircraft. The pressure deck includes longitudinal beams extending in a forward and aft direction between an aft wheel well bulkhead and a rear spar of the aircraft. The pressure deck also includes a web attached to an underside of the longitudinal beams. The web includes a flat web portion supported by transverse stiffeners extending in an inboard and outboard direction, and a curved web portion including arches configured to flex laterally from load in the inboard and outboard direction. A transition between the flat web portion and the curved web portion extends at least partially in the forward and aft direction of the aircraft.

Abstract: The present disclosure is directed to a blended wing body aircraft including a blended wing body, wherein the blended wing body is characterized by having no clear dividing line between wings and a main body along a leading edge of the aircraft, at least a rib, wherein the at least a rib runs longitudinally from fore to aft of the main body, and a plurality of transparent panels located in the top surface of the main body, wherein the plurality of transparent panels are located in channels, wherein the channels are separated by the at least a rib.

Abstract: A trunk route aircraft has at least one wing for supporting the aircraft during flight, and at least one propulsor for forward propulsion of the aircraft. The trunk route aircraft further includes a pressurized trunk route fuselage having a double-bubble cross-sectional shape and a generally vertically-oriented longitudinal bulkhead dividing the trunk route fuselage interior into two side-by-side trunk route payload compartments. The longitudinal bulkhead is loaded in tension when the trunk route fuselage is pressurized. The trunk route payload compartments are each configured to receive a plurality of lightweight ISO (International Organization for Standardization) geometry containers arranged end-to-end, or a plurality of container inserts arranged end-to-end, each container insert also configured to be received within the lightweight ISO-geometry container, or a combination of one or more lightweight ISO-geometry containers and one or more container inserts arranged end-to-end.

Abstract: Coupler assemblies are described that removably couple sides of an auxiliary fuel tank in a cargo area of an aircraft. In one embodiment, a first coupler of the coupler assemblies includes a first attachment member that supports a body with a hollow channel having a centerline disposed longitudinally in the fuselage between a first end and a second end, and a slot between an outer surface of the body and the hollow channel. A second coupler of the coupler assemblies includes an engagement member, a second attachment member, and an arm extending between the engagement member and the second attachment member. The engagement member is slidably received within the hollow channel from the first end, and fits slidably within the hollow channel to engage with the body of the first coupler, with the arm extending through the slot.

Abstract: An aircraft pressurized cabin door (1) having an outer panel (2) and a door structure (3) including: two circumferential beams (4) fastened to the lateral edges of the door; a plurality of longitudinal beams (5a, 5b) which are arranged substantially perpendicularly between the circumferential beams (4) and are fastened to the outer panel (2), each longitudinal beam (5a, 5b) extending from one circumferential beam (4) to the other. At least one longitudinal beam (5b) is a beam that has a variable cross-section which increases from the ends (B, M) of the beam to the center (H, L) of the beam, with two bent support bars.

Abstract: An unmanned aerial vehicle may include a fuselage and an anchor structure coupled to the fuselage and including a wing retention structure and a power module retention structure. The unmanned aerial vehicle may also include a wing releasably coupled to the wing retention structure, thereby coupling the wing to the fuselage, and a power module releasably coupled to the power module retention structure, thereby coupling the power module to the fuselage.

Abstract: A system for a blended wing body aircraft with a combustion engine is illustrated. The aircraft comprises a blended wing body, at least a fuel source located within the blended wing body and configured to store a fuel, wherein the fuel includes liquid hydrogen, and at least a propulsor configured to propel the blended wing body aircraft. The at least a propulsor comprises a combustion engine configured to burn the fuel from the fuel source and produce mechanical work to power the at least a propulsor.

Abstract: An aircraft includes a fuselage that provides an aircraft passenger cell and a plastically deformable protective body secured on the fuselage. The plastically deformable protective body can be secured on the bottom of the fuselage and/or laterally on the fuselage. The plastically deformable protective body can be secured releasably on the fuselage, for example, via a screw connection.

Abstract: A polymer formed of at least one phenylphosphine oxide functional epoxide crosslinked with at least one phenylphosphine oxide amine such that the polymer has phosphorous concentrations of at least about 8 percent by weight, at least about 8.5 percent by weight, or any value or range of values therebetween.

Abstract: An emergency opening device of an aircraft door including a tubular actuating member (2); a resilient compression device; a retaining member for retaining the tubular actuating member (2), having a retaining wire (12) which, when the tubular actuating member (2) is in the retracted position, is held taut between a first attachment (14, 17) and a second attachment (16, 18); a release device which includes a cutting member (22) for transversely cutting the retaining wire (12).

Abstract: Embodiments are directed to a fuel cell protection system comprising an aircraft fuselage having an inner surface and an outer surface, an attachment point mounted on the outer surface, an aircraft fuel cell spaced apart from the inner surface, and a plate positioned between the inner surface and the aircraft fuel system, the plate spaced apart from the inner surface to create a void space. The attachment point may be a cargo hook. The void space is configured to receive all or a portion of the cargo hook after a crash. The plate creating the void space may be a rigid material or may be a ballistic fabric material.

Abstract: A cable management system includes a mounting bracket having a backing plate, two face mounts, and a panel, said face mounts each include an orifice and an aperture of different inner diameter, said panel includes a number of openings and a number of holes of different inner diameter, a extender bracket includes two walls and two end pieces secured together, said walls and said end pieces each include an eyelet and a piercing of different inner diameter, a fastening member includes a backing plate insert for engaging with said orifice of said face mounts and said eyelet of said walls and said end pieces of said extender brackets, a screw hole formed in said fastening member and formed through said backing plate insert, and an inner thread formed in said fastening member and spaced from said screw hole and said backing plate insert for engaging with bolts.

Abstract: Systems and methods are provided for fabricating a fuselage of an aircraft. The method includes: disposing arcuate sections of fuselage at a track of a factory such that concavities of the arcuate sections of the fuselage face a floor of the factory, and bearing edges of the arcuate sections of fuselage directly contact the track; advancing the arcuate sections of fuselage synchronously along the track in a process direction; and performing work within concavities of the arcuate sections of fuselage during pauses between pulses of the arcuate section of fuselage via stations that are disposed beneath the concavities and that are directly mounted to the floor of the factory.

Abstract: An ultrasonic airflow severing resistance reducing device for vehicles, including an airflow severing blade assembly, shock-absorbing installation assemblies, ultrasonic vibration components, and a rubber sealing ring assembly; a bottom portion of the airflow severing assembly is provided with an accommodating cavity; a top end of each shock-absorbing installation assembly is fixedly connected to an inner cavity wall of the accommodating cavity; a bottom end of each shock-absorbing installation assembly is formed with a fixed installation bottom portion; the ultrasonic vibration components are installed on the inner cavity wall; the rubber sealing ring assembly is arranged and installed on the airflow severing blade assembly. The ultrasonic vibration components drive the airflow severing blade assembly to generate high frequency ultrasonic vibration to sever airflow.

Abstract: An aircraft defining a longitudinal direction and a lateral direction is provided. The aircraft includes: a fuselage; an engine mounted at a location spaced from the fuselage of the aircraft, the engine comprising a plurality of rotor blades; and a fuselage shield attached to or formed integrally with the fuselage at a location in alignment with the plurality of rotor blades along the lateral direction, the fuselage shield comprising a first layer defining a first density and a second layer defining a second density, the first density being different than the second density.

Abstract: The present invention is directed to an apparatus for managing thermal energy of an electric aircraft energy source. Apparatus may include fins, which extend from a skin of electric aircraft. The energy source may bias or be adjacent to the fins so that heat energy may dissipate from the energy source and through the fins and, thus, the skin. A coolant may also be run through the apparatus, where the coolant may flow through channels that are disposed between the fins.

Abstract: A method for loading an Unmanned Aerial Vehicle with one or more items is disclosed. The method includes positioning one or more items in specific positions within one of the Unmanned Aerial Vehicle and a container configured to be carried by the Unmanned Aerial Vehicle based on a Center of Gravity of each of the one or more items. The method also includes securing the one or more items in the specific positions within the one of the Unmanned Aerial Vehicle and the container to prevent the one or more items from shifting and changing a combined Center of Gravity of the one or more items combined with the one of the Unmanned Aerial Vehicle and the container during a flight of the Unmanned Aerial Vehicle.

Abstract: Methods and systems for efficiently loading cargo transports, such as cargo aircraft, are described. The methods and systems rely upon payload profiles for various payloads where the payloads include repeatable payloads that have the same characteristics. Based on the payload profile, the payload is positioned at a designated location in an interior cargo bay of the cargo transport. The designated location is denoted by one or more pre-formed markings in the interior cargo bay that establish where a payload having the respective payload profile should be positioned in the bay. The payload can then be secured in the bay. Because the designated location accounts for centers of gravity, the payload can be loaded and secured in the bay without having to run various calculations each time a payload is loaded. Systems and methods related to how the payloads are packaged in an efficient, expeditious manner are also provided.

Abstract: A method for loading one of an Unmanned Aerial Vehicle (UAV) and a container for the Unmanned Aerial Vehicle with one or more items is disclosed. The method includes determining a Center of Gravity (COG) of the one or more items. The method also includes loading the one of the UAV and the container for the UAV with the one or more items based on the COG of the one or more items. The method further includes positioning one or more weights relative to the one or more items and relative to the one of the UAV and the container for the UAV such that a combined COG of the one or more items, the one of the UAV and the container for the UAV, and the one or more weights is positioned within a predetermined region relative to the one of the UAV and the container for the UAV.

Abstract: An aircraft fuselage portion extending in a general longitudinal direction and comprising a fuselage structure comprising annular frames and a flat floor. The fuselage portion also comprises struts perpendicular to the floor in a nominal position and extending from the floor to a frame. Each strut comprises, in the vicinity of at least one of the ends thereof, a detachable link so that the strut can be moved relative to the fuselage structure or separated from the fuselage structure to temporarily grant access to a triangle area located between the frames, the floor and the struts in the nominal position. This allows access to be granted to the area in which the ducts must be installed in the aircraft, in particular, in the form of sets of ducts assembled prior to their installation in the fuselage.

Abstract: A rotor system including a rotor hub, a plurality of rotor blades supported by the rotor hub, and a fairing mounted to the rotor hub. The fairing includes an external surface exposed to an external airflow and an internal surface defining an interior portion. A component system is mounted to the rotor hub in the interior portion. The component system includes a first heat generating component and a second heat generating component spaced from the first heat generating component. A cooling duct is arranged between the first heat generating component and the second heat generating component.

Abstract: A stringer runout configuration has a pair of fittings with each fitting having a fitting web that is configured for attachment to a stringer web of a stringer on opposite sides of a terminating end of the stringer. The stringer web has a terminating end with a curved configuration and base flanges with rounded terminating ends. Each fitting has a base flange that has a bottom surface with a first surface area and a second surface area positioned at different heights. The first surface area of each of the fittings is configured for attachment to a stringer base flange on opposite sides of a terminating end of the stringer. The second surface area of each of the fittings is configured for attachment to a composite panel surface adjacent the terminating end of the stringer. These and other detailed design features described herein enhance the capability of the runout configuration.

Abstract: An engine that may comprise a first rotatable shaft, a second rotatable shaft, and a turnbuckle shaft. The first shaft rotatable may be disposed about a centerline axis and have threads disposed thereon. The second shaft rotatable may be disposed about the centerline axis and have threads disposed thereon. The turnbuckle shaft may be axially disposed between the first and second shafts, rotatable about the centerline axis, and have threads disposed thereon for engaging the threads of the first and second shafts. The first and second shafts may be drawn together by a force acting on the threads of at least one of the first and second shafts created by a rotation of the turnbuckle shaft relative to the at least one of the first and second shafts. The turnbuckle shaft may rotationally connect the first shaft and second shaft.

Abstract: Embodiments are directed to an aircraft fuselage comprises two keel beams and two roof beams. Each keel beam is formed as a single component having no joints. Each keel beam comprises a first portion that is configured to define a floor of an aircraft and a second portion that is configured to define a tail section of an aircraft. The second portion is positioned at an angle relative to the first portion. Each roof beam is coupled to the second portion of a corresponding keel beam at a point remote from the first portion. Each roof beam and a corresponding keel beam are positioned along a single butt line relative to an aircraft fuselage centerline. Frame members are coupled to both keel beams and both roof beams.

Abstract: A telescoping tail assembly for use on an aircraft having a fore-aft length. The telescoping tail assembly includes a housing extending in an aftward direction, a tailboom slidable along the housing into various positions including an extended position and a retracted position and one or more control surfaces coupled to the tailboom. The tailboom increases the fore-aft length of the aircraft in the extended position and decreases the fore-aft length of the aircraft in the retracted position.

Abstract: Systems, apparatus, and methods are provided for retrieving data from remotely deployed sensor systems. Flight control systems are also provided for maintaining the orientation of a high gain antenna affixed to an aircraft relative to a stationary or nearly stationary transceiver.

Abstract: A flexible strengthening joint for a pressurized vessel includes an outer skin having a localized abrupt change in shape. The outer skin includes a first skin section and a second skin section, the localized abrupt change in shape being located at a junction between the first skin section and the second skin section. A reinforcing bulkhead is located in the interior of the pressurized vessel. The reinforcing bulkhead includes a first bulkhead section that is directly attached to the first section of the outer skin and a second bulkhead section that unattached directly to the first section. A kick frame is located in the interior, the kick frame spanning at least the second bulkhead section. At least one intercostal is secured to the second bulkhead section. The at least one intercostal is also secured to the kick frame.

Abstract: An unmanned aerial vehicle (UAV) for gas transport is disclosed. The UAV includes a fuselage enclosing a volume, and a gas reservoir enclosed within the fuselage, filling at least a majority of the volume. The gas reservoir is configured to receive and store a gas at a pressure no greater than 100 bar. The UAV also includes a propulsion system having at least one engine, each of the at least one engine coupled to a prop that is driven by the at least one engine using energy derived from the gas stored in the gas reservoir. The UAV also includes a control system communicatively coupled to the propulsion system and configured to operate the unmanned aerial vehicle to autonomously transport the gas. The UAV may have a footprint while on the ground, and the footprint of the UAV may be no larger than three standard parking spaces.

Abstract: The present vertical lift vehicle system can include a single internal combustion engine, a single propeller, and a plurality of small ducts. The small ducts can connect to a single main duct acting as a combustion chamber, wherein the combustion chamber combines air from the small ducts with propane, wherein when ignited the contents of the main duct produce added thrust to the vehicle as it exits the main duct.

Abstract: A pressure deck system for a fuselage of an aircraft. The pressure deck system comprises a first sloping outboard pressure panel, a first longitudinal stiffener connected to the first sloping outboard pressure panel, a second sloping outboard pressure panel opposite the first sloping outboard pressure panel, a second longitudinal stiffener connected to the second sloping outboard pressure panel, pressure panels between the first sloping outboard pressure panel and the second sloping outboard pressure panel and forming the an upper barrier of a wheel well, longitudinal beams connected to the pressure panels and supporting a cabin floor of the fuselage, and a sloping pressure deck connecting a number of these components to the rear spar of the center wing box. A waterline of the pressure deck system is de-coupled from a side-of-body waterline in the fuselage.

Abstract: In one aspect, there is a composite skin for a tiltrotor aircraft including a first skin having a periphery defined by a forward edge, an aft edge, and outboard ends; a second skin; and a honeycomb core disposed between the first skin and the second skin, the honeycomb core comprised of a plurality of honeycomb panels positioned along the longitudinal axis of the first skin, the plurality of honeycomb panels having an array of large cells, each cell having a width of at least 1 cm; wherein the second skin and the honeycomb core have an outer perimeter within the periphery of the first skin.

Abstract: A reinforced, foldable component for an aircraft is provided, configured to stabilize a high frequency aeroelastic fluttering movement. The reinforced component may include a frame structure defining at least one air chamber, and a plurality of sealed compartments. A shear thickening fluid is disposed in at least one of the sealed compartments, exhibiting a decreasing viscosity responsive to an impact force. The frame structure may define one of an inflatable wing structure, a fairing structure, an aileron structure, and a stabilizer structure, and the like. The foldable component may include an exterior layer with an exterior surface exposed to an external environment and an interior layer adjacent the at least one air chamber, wherein the plurality of sealed compartments are disposed between the exterior layer and the interior layer. The exterior layer or the interior layer may include an impact-resistant fabric layer including a shear thickening material.

Abstract: A method of fabricating a panel for a helicopter airframe configurable in a plurality of helicopter configurations comprises the following steps. Operational characteristics of the helicopter airframe are defined. A skin panel is provided, where the skin panel is configured according to the operational characteristics of the helicopter airframe. A brace region is defined relative to the skin panel based on the operational characteristics of the helicopter airframe and the plurality of helicopter configurations. A brace assembly is operatively connected to the skin panel within the brace region to form a blank panel assembly. Accessories are arranged relative to the blank panel assembly according on one of the helicopter configurations to obtain a configured panel assembly.

Abstract: A method for loading an Unmanned Aerial Vehicle with one or more items is disclosed. The method includes determining a Center of Gravity of each of the one or more items. The method also includes matching a combined Center of Gravity of the one or more items with a Center of Gravity of the Unmanned Aerial Vehicle.

Abstract: A method for loading an Unmanned Aerial Vehicle with multiple items is disclosed. The method includes determining a weight, size, and Center of Gravity of each of the multiple items. The method also includes positioning the multiple items relative to one another such that a combined Center of Gravity of the multiple items will be positioned within a predetermined region. The method further includes loading the multiple items onto the Unmanned Aerial Vehicle with the combined Center of Gravity of the multiple items positioned within the predetermined region.

Abstract: A seal for sealing an aircraft fuel tank, an aircraft wing rib and stringer sealing assembly, an aircraft wing fuel tank, an aircraft structural wing box, an aircraft wing, and a method of sealing an aperture are disclosed. The seal is for sealing a wing rib to a stringer passing through an aperture in the rib at a variable position in the aperture. The seal includes self-adjustment means to absorb any tolerance when forming the seal, upon the stringer being assembled into the aperture in the rib.

Abstract: Structural composite airfoils include a primary structural element and a secondary structural element defining the trailing edge of the structural composite airfoil. The primary structural element includes an upper skin panel, a lower skin panel, and a middle C-channel spar that is coupled to the upper skin panel and the lower skin panel. The upper skin panel extends from an upper leading edge end to an upper trailing edge end, and the lower skin panel extends from a lower leading edge end to a lower trailing edge end. The lower leading edge end of the lower skin panel is coupled to the upper leading edge end of the upper skin panel within the leading edge region of the primary structural element.

Abstract: A method for installing a fastener system. A position on a structure relative to an overhang on the structure is automatically sensed for installing a fastener system in a hole using an offset collar installer. The offset collar installer is moved about a rotation axis to the position such that a collar in the fastener system is held in the position over the hole. The offset collar installer is connected to a platform and rotatable about the rotation axis. The collar is fastened to an engagement feature for a bolt in the hole.

Abstract: Systems and methods for a caul plate for an irregular surface. One embodiment is a caul plate for co-curing or co-bonding a first composite part and a second composite part. A body of the caul plate includes a lower surface to face a top surface of the first composite part, a reference edge to locate the second composite part on the first composite part, and an upper surface that is opposite to the lower surface. The lower surface includes one or more bends to match one or more slopes in the top surface of the first composite part. The one or more bends correspond with ply changes in the first composite part.

Abstract: There is provided an air grille panel assembly for a vehicle. The assembly includes an air grille panel having air grille openings, a top end, and a bottom end. The top end is configured for coupling to a sidewall panel in a cabin of the vehicle. The bottom end is configured for coupling to a raceway assembly on a floor in the cabin. The assembly further includes a frame member disposed around a perimeter of each of the air grille openings, to define each of the air grille openings, an air grille coupled to the frame member and covering each of the air grille openings, and a cover member releasably attached to the air grille. The assembly is configured for coupling to the sidewall panel, via a float attachment, that allows for a vertical adjustment, to accommodate different installed positions of the assembly in the cabin of the vehicle.

Abstract: A moisture control system includes an anode coupled to an insulation blanket that is positioned between an inner wall and an outer wall of an aircraft fuselage, a cathode coupled to an interior surface of the outer wall, and a power control unit coupled to the anode and the cathode to apply voltage across the anode and the cathode. When the voltage is applied across the anode and the cathode, moisture is drawn away from the anode and toward the cathode on the interior surface of the outer wall and guided along a drainage path provided via structural members disposed between the inner wall and the outer wall toward a drainage port.

Abstract: An aircraft structure (11) for flow control including a perforated panel (13) having an inner surface (15) directed to a structure interior (17), an outer surface (19) in contact with an ambient flow (21), and a plurality of micro pores (23) connecting the inner and outer surfaces (15, 19). Elongate crack stopper elements (25) are attached to the inner surface (15) of the perforated panel (13). The crack stopper elements (25) are configured to inhibit crack propagation within the perforated panel (13).

Abstract: A stiffened structural component for an aircraft includes a first material sheet with a first surface, and at least one elongate bulge that bulges out in a direction transverse to the first surface in order to stiffen the structural component, wherein each of the at least one bulge comprises two edges that extend along the first surface, wherein a continuous bulging surface extends between the edges, and wherein the bulges are formed integrally into the first material sheet through pressing.

Abstract: Disclosed herein is a body of a mobile vehicle. The body includes skin, a stringer, and a frame. The skin comprises a first tab and a second tab, opposite the first tab. The first tab is fixed directly onto the skin and the second tab is fixed directly onto the skin. The frame comprises a cut-out, a first foot, and a second foot. The second foot is spaced apart from the first foot by the cut-out. The first foot is fixed directly onto the first tab of the stringer, such that the first tab of the stringer is immediately interposed between the first foot of the frame and the skin. The second foot is fixed directly onto the skin, such that no portion of the frame is fixed directly onto the second tab of the stringer.

Abstract: A method for designing the cross-sectional shape of the fuselage of a flying body having the fuselage extending in the roll axial direction, the section being taken on a plane perpendicular to the roll axial direction. This method is provided with: an initial setting step S12 for setting an initial cross-sectional shape, which is the initial cross-sectional shape of the fuselage having a cross-sectional shape that is not truly circular; load application steps S14, S21, S28 for analytically or experimentally preloading the fuselage having the initial cross-sectional shape; and a design shape setting step S17 for acquiring the cross-sectional shape of the preloaded fuselage as the design cross-sectional shape of the fuselage.

Abstract: A flooring system for enclosures or vehicles, such as an aircraft flooring architecture, includes a flooring panel with at least an upper layer, a core ply, and a bottom layer. The bottom layer of the flooring panel has a top face and a bottom face, an upper layer of the flooring panel has an upper face and a lower face, and a core ply of the flooring panel has an upper surface bonded to the lower face of the upper layer and a bottom surface bonded to the top face of the bottom layer. The bottom face of the bottom layer is located on a structural floor of an enclosure or vehicle, such as the aircraft, and the bottom layer of the flooring panel slides over the structural floor.