Abstract: The present disclosure relates to a steering stabilizer for a vehicle. The stabilizer has a damper having a housing, a piston rod extending telescopically from the housing, and a coil spring disposed over the damper. An inner adapter assembly secures a first end of the damper to one of a wheel component or a body component of the vehicle. An outer adapter assembly is coupled to a distal end of the piston rod and couples to the other one of the wheel or body component. A one-piece spring seat is fixedly coupled to the housing. The coil spring is supported at a first end by the spring seat and at a second end by the outer adapter assembly. The spring seat enables the single coil spring to return the steering stabilizer to a central position regardless of whether the single coil spring is under tension or compression.

Abstract: A rear wheel steering apparatus may include: a driving part housed in a housing part; a rotating part rotated by the driving part; a moving shaft part connected to tie rods, and screwed to the rotating part; a spline plate spline-coupled to the moving shaft part so as to restrict rotation of the moving shaft part; and a space maintaining part protruding from the moving shaft part or the spline plate, and maintaining a space between the moving shaft part and the spline plate.

Abstract: To provide a vehicle body structure for an autonomously traveling vehicle that is distinguished for maintainability. A vehicle body structure (1) for an autonomously traveling vehicle that travels on wheels (3) provided on a chassis (2) includes side frames (4R), (4L) that extend in a chassis longitudinal direction on both sides of the chassis with respect to a chassis width direction, first drive units (20) in each of which a drive motor (5) that is for driving the wheel (3), a reduction gear (6), and a drive shaft (7) that drives the wheel (3) are integrally configured, and second drive units (30) which each rotatably hold a drive shaft (7) that drives the wheel (3). The vehicle body structure (1) is characterized in that the first drive units (20) and the second drive units (30) are each provided so as to be integrally mountable in and dismountable from the same side frames.

Abstract: In a vehicle comprising a manoeuvring system for manoeuvring a predetermined part of the vehicle into a target position provided by a target object, wherein the manoeuvring system comprises a first optical sensor device, arranged at the vehicle, for capturing the target object and a calculating device for calculating a trajectory of the predetermined part of the vehicle into the target position with the aid of an image of the target object captured by the first optical sensor device, fast and safe manoeuvring should be facilitated by improved monitoring of the manoeuvring process and an improved calculation of the trajectory of the predetermined part of the vehicle into the target position, as a result of which accidents and damage to humans, vehicles and wares are avoided. This is achieved by virtue of the manoeuvring system comprising a second optical sensor device arranged at the vehicle in a manner offset relative to the first optical sensor device in the longitudinal direction of the vehicle.

Abstract: A front vehicle body reinforcing structure may include a dash panel, a front side member extending along a length direction of a vehicle for coupling to a lower part of the dash panel, a fender apron member extending along the length direction of the vehicle and coupled to an upper part of the dash panel, a front shock absorber housing having a lower part coupled to the front side member and an upper part coupled to the fender apron member, a cowl cross member extending along a width direction of the vehicle for coupling to the upper part of the dash panel and having both ends overlapping and coupled to the front shock absorber housing along the width direction, and a front shock absorber housing side member adhered to an inner surface of the front shock absorber housing, and having an upper part coupled to the cowl cross member.

Abstract: A motor vehicle rear parcel shelf configured to separate the passenger compartment from the luggage compartment of the vehicle, the motor vehicle rear parcel shelf including a first beam and a second beam, the first and second beams including composite material and configured to be rigidly connected to the two sides of the body of a motor vehicle, and a panel connecting the two beams together.

Abstract: An instrument carrier of a motor vehicle includes at least one hollow space lying in an end region transversely to the driving direction. The hollow space has an inner surface forming a slide-in contour. A housing is arranged in the hollow space, which contains a vehicle component.

Abstract: An automotive vehicle includes a body with a front portion and a rear portion. The vehicle additionally includes a spoiler coupled to the rear portion. The spoiler includes a first portion, a second portion, and a cap. The first portion includes a first plastic material, the second portion includes a second plastic material, and the cap includes a third plastic material. The second plastic material is distinct from the first plastic material. The second portion is disposed between the first portion and the cap. The second portion has a through hole extending therethrough. The cap has a diameter exceeding that of the through hole. The first portion and the cap are welded together via the through hole to mechanically secure the second portion to the first portion.

Abstract: A vehicular sensing system, a vehicle and a method of performing one or both of vehicular mapping and navigating operations using the sensing system. The sensing system is secured to a roof or other suitable location on the vehicle and includes one or more sensors configured to acquire at least one of vehicular mapping and navigational data, a retractable mounting structure to move the sensor or sensors between a deployed and stowed position, and an aerodynamic spoiler, air dam or deflector. The body of the spoiler acts as a housing with a recess formed in its upper surface such that upon placement of the spoiler on the roof, the recess provides a location within the spoiler to permit storage of the mounting structure and sensors when they are in their deployed (non data-acquisition) mode of operation. The size and placement of the mounting structure and sensors is such that they do not detract from the aerodynamic or aesthetic qualities of the spoiler.

Abstract: An aerodynamic resistance reduction system for a vehicle is provided and includes a pair of vertical panels pivotally attached to a rear end adjacent to rear vertical edges of a vehicle, a first horizontal panel assembly pivotally attached to a top end to each of the pair of vertical panels and pivotally attached to the rear end adjacent to a top horizontal edge of the vehicle, and a second horizontal panel assembly pivotally attached adjacent to an inside surface of each of the pair of side panels, the second horizontal panel assembly being disposed between the first horizontal panel assembly and a lower edge of the rear end of the vehicle.

Abstract: Disclosed herein are embodiments of a reinforcement or brace that can be installed on the tailgate of a vehicle. The reinforcement can provide structural support for heavier mounted objects, such as tires, as well as allowing for different attachment points. Advantageously, the tailgate hinge does not need to be removed or replaced.

Abstract: Related primary to transportation: the device being the Urbamobile Transport System carried out in such a manner that it consists of individual elements performing the functions of a transport mean, with possibility of motion and to be motionless of each element both separately and in contact; the method being the method of exploitation of the transport system, at which forming the transport system individual elements, performing the functions of a transport mean, are moved and placed motionless both separately and in contact. The task is provided, for the first time, to obtain the technical means performing the function of the Urbamobile Transport System, by what the engineering result is achieved that consist in the implementation of the Urbamobile Transport System.

Abstract: A main ballasting weight (10) straight from the foundry for a farming tractor, comprising upper faces and lower faces (11, 12), two faces (13, 14) oriented transversely to the direction of movement of the tractor, and two lateral faces (15, 16) to parallel to the direction of movement of the tractor, said lower face comprising dovetail type means of connection (121, 122) to provide an anchoring with a secondary weight, said upper face forming an upper plate comprising a means of pre-positioning and centring (110) of a box (20) designed to be mounted on said main weight, said lateral faces (15, 16) being able to cooperate with lateral flanges (22, 23) of said box which are is attached bearing against said lateral faces and having fixation orifices (150) able to receive fixation screws cooperating with said lateral flanges for the fixation of said box to said main weight.

Abstract: A track roller assembly may have a track roller, a roller shaft and collars press fit onto either end of the roller shaft to retain the track roller on the roller shaft with an axial clearance between the collars and the track roller. During assembly, the collars may be press fit onto the shaft ends and forced axially inwardly until further axial movement of the collars is prevented by engagement shoulders of the track roller. A compressive axial load may be applied to the roller shaft to reduce a shaft length of the roller shaft and to cause the roller shaft to slide inwardly relative to the collars. The compressive axial load is removed from the roller shaft so that the roller shaft extends back to the normal shaft length and the collars move axially farther apart as the roller shaft extends back to the normal shaft length.

Abstract: A method for manufacturing a vehicle frame is disclosed. An upper body of the vehicle frame is formed, the upper body configured to be joined with an underbody of the vehicle frame at a first component of the upper body. The underbody of the vehicle frame is formed, the underbody configured to be joined with the upper body at a first component of the underbody. After forming the upper body and the underbody, a point on the upper body is aligned with a desired position for the point, independent of an alignment between the first component of the upper body and the first component of the underbody. After aligning the point on the upper body with the desired position for the point, the first component of the upper body is joined to the first component of the underbody.

Abstract: The present invention relates to a bicycle training wheel assembly that uses uniquely, spherical wheel made of rubber or polyurethane substances of optimal consistency for this utility, as opposed to using the conventional cylindrical wheel. The foregoing properties of the said spherical wheel provide bounce and shock absorption. This invention allows the rider to obtain better balance and stability while learning to ride the bicycle. The assembly attaches to both sides of the rear wheel axle of the bicycle.

Abstract: The present invention relates to an assembly for storing bicycles in an upright orientation and suitably with both wheels of the bicycles off the ground. In addition, the present invention is adapted to suspend the bicycles from their front wheel by engaging the front tyre of the bicycles, and without needing to engage the rim of the front wheel, or the frame of the bicycle. Moreover, the assembly is adapted to allow the bicycles located in the upright orientation to be moved while on the assembly from side-to-side to allow bicycles storage to be clustered together and a bicycle to be retrieve from storage to be spaced further apart from adjacent bicycles.

Abstract: In a pannier mounting structure, a pannier is mounted on a side portion in a vehicle widthwise direction of a motorcycle through a pannier stay. The pannier stay includes a first retaining portion and a second retaining portion beneath the first retaining portion. The pannier has a rear surface provided with a first retaining bag that opens downwards and a second retaining bag that is positioned below the first retaining bag and opens upwards. While the first retaining portion is inserted into the first retaining bag through an opening in a lower portion thereof, the second retaining portion is inserted into the second retaining bag through an opening in an upper portion thereof and is engaged within the second retaining bag.

Abstract: A forward view mirror housing is coupled to an adjustable frame attachment which attached to the handle bar of a conventional bicycle allowing a user to view forward while riding in a forward leaning position.

Abstract: A scooter having at least two front wheels, a rear wheel, a deck, a steering assembly that includes a handlebar and a steering tube, an electric motor configured to provide power, and a transmission configured to transfer the power provided by the electric motor. The transmission can be configured to transfer the power provided by the electric motor only to the rear wheel. In some configurations, the scooter includes a battery, a power switch, and a controller coupled to the power switch, the battery, and the electric motor. In response to receiving a signal from the power switch, the controller ramps up the voltage provided to the electric motor over an interval of time.

Abstract: The present invention relates to a swing vehicle technical fields, and more particularly to a self-balance vehicle. It includes a main body of the self-balance vehicle, a first wheel and a second wheel, the first wheel and the second wheel is respectively installed at both sides of the main body of the self-balance vehicle, the outside of the first wheel is installed a folding first foot petal, the outside of the second wheel is installed a folding second foot petal. Compared with the prior art, in the self-balance vehicle of the present invention the first foot petal and the second foot petal can be overlapped, its volume is compact after folding, it is convenience for carry, its appearance is small and beautiful.

Abstract: A ride-height robust sensor measures shock absorber travel and monitors absolute ride-height in a front and rear shock absorber of a motorcycle regardless of varying cargo weights. Rather than modifying the frame, the sensor is mountable directly to a motorcycle rear shock absorber using a novel upper mount and lower mount. A second sensor is mountable to a front shock absorber using a novel ride-height upper fork bracket and ride-height lower fork bracket. A novel ride-height display module and attendant control module provide a visual display of shock height using a multicolored six LED array. User-customised ride-height and dismount height are activated upon motor ignition and cutoff using a solenoid control module. Components are electronically isolated from the motorcycle ignition system and shock solenoids for accuracy and reliability. The ride-height controller enters sleep mode when not in use and is installable by the user.

Abstract: A cable positioning structure for hydraulic brake of a bicycle is disclosed. The cable positioning structure comprises the caliper and the transmission member connected with each other, and is capable of connecting with original braking cable. It is not necessary to arrange an oil pipe to connect the handlebar and to drive the piston, and easy to be assembled or de-assembled and cost down.

Abstract: A drive train for a treadle scooter using a locking roller clutch on each side of a drive wheel substantially equalizes drive line pull at actuation pulleys operatively associated with the locking roller clutches as a user pivots a rocker board having its ends attached to ends of the drive line.

Abstract: A drive for a wheeled vehicle having a passive wheel and a driven wheel is described. The driven wheel is driven by a gear. The drive includes a support mounted an axle of the driven wheel and attached to a frame element of the vehicle. A motor is located at the driven wheel. This motor is mounted on the support. A second drive gear connected to the drive motor wherein said second drive gear is also mounted on the support. The second drive gear engages the gear fixed to the driven wheel.

Abstract: A catalytic converter for treatment of exhaust gases from a motorcycle engine includes a housing having an upstream end and a downstream end. A housing body extends between the upstream end and the downstream end. A catalyst mantle is positioned within the body of the housing such that a void is formed between the catalyst mantle and the housing body. A catalyst is positioned within the catalyst mantle. An insulator is positioned within the void between the housing body and the catalyst mantle.

Abstract: A first sprocket includes a first opening having a first diameter smaller than a radially outer diameter of a sprocket support portion of a bicycle rear hub assembly. A lock member includes a main body, a male thread portion, and a radial projection. The main body has a first axial end configured to pass through the first opening and a second axial end opposite to the first axial end in an axial direction. The male thread portion is provided to the first axial end and configured to engage with a female thread portion of the bicycle rear hub assembly in a state where a bicycle rear sprocket assembly is mounted to the bicycle rear hub assembly. The radial projection extends radially outwardly from the second axial end to restrict axial displacement of the first sprocket with respect to the sprocket support portion in the state.

Abstract: A bicycle bar end attachment includes a main body, a shoe, a compression member, a rotation member, a transmission structure and a fixing structure. The main body is insertable into a bicycle handlebar, and includes a first threaded portion. The shoe is located between an inner surface of the handlebar and the main body. The compression member includes a second threaded portion engaged with the first threaded portion and a first pressing surface contacting one end of the shoe. The rotation member includes an exposed portion accessible from outside the handlebar and a second pressing surface contacting the other end of the shoe. The transmission structure transmits rotation of the rotation member to the compression member. The fixing structure holds the shoe between the compression member and the rotation member, and moves the shoe in a radial direction of the handlebar to fix the main body to the handlebar.

Abstract: A watercraft can include a foil configured for movement between an undeployed position and a first deployed position in which the foil raises the relative position of the watercraft relative to the water line as the watercraft moves forward through the water, thereby facilitating planing of the watercraft. The foil can be configured for movement to a second deployed position in which the foil lowers the relative position of the stern end of the watercraft as the watercraft moves forward through the water, thereby modifying the wake produced by the watercraft.

Abstract: A system assists the driving of a ship and is configured to estimate the structural loads of the ship due to the direct wave excitation, and structural loads of the ship due to the whipping effect caused by the wave slamming. The system includes at least one reference sensor adapted to provide an indication of a motion or stress magnitude at a predetermined point of the ship structure, and is further configured to calculate an estimate of the magnitude at the predetermined point in the ship structure, compare the indication of magnitude with the estimate of the magnitude so as to determine an offset value, and correct the estimates of the structural loads and/or the estimate of the magnitude on the basis of the offset value.

Abstract: A bimini top for a boat. The bimini top includes a cover and a frame supporting the cover. The frame may include a first support pivotally connected to an inboard side of a first leg of a tower. The first support has a profile in a stowed position that, when viewed from the port side in the stowed position, is hidden behind the portion of the first leg with the first profile. The frame may also include a second support pivotally connected to an inboard side of a second leg of the tower. The second support has a profile in the stowed position that, when viewed from the starboard side in the stowed position, is hidden behind the portion of the second leg with the second profile. The bimini top may also include a line including a plurality of hangers is integrally formed in the line.

Abstract: A security device comprising: a plate (20) having an upper portion (21) and a lower portion (22), wherein the upper portion and the lower portion are parallel and off-set; a bulbous barrier (30), wherein the upper portion of the plate and the barrier form a slot (50) therebetween, and the barrier extends in a direction perpendicular to the upper portion of the plane of the plate and away from the slot.

Abstract: The present invention provides a device useful for transporting and/or handling equipment in an underwater environment for performing work, the device comprising at least the following components: a floating hydraulic unit (1) comprising a first enclosure (1a), preferably with a cylindrical wall, containing an electrical pump unit (6), a battery (8) suitable for electrically powering the pump unit, and a fluid tank (7), preferably containing oil, said first enclosure (1a) being suitable for being made submersible by first ballast (16); at least one hydraulic tool (3) connected or suitable for being connected to at least one hydraulic coupling (11, 12) of said hydraulic unit via at least one flexible hose (30); at least one independent float (4), preferably having a cylindrical wall, connected or suitable for being connected to said hydraulic tool (3) via a sling (5) of adjustable length, said float (4) being suitable for being made submersible by second ballast (43); and a wired remote control (2) for swit

Abstract: A motorized water sports equipment rack and method for motorized swiveling of a water sports equipment rack attached to a boat are disclosed. The motorized water sports equipment rack includes a mounting bracket for securing the mounting bracket to the boat and a water sports rack mounting bolt connected to the mounting bracket. A swivel bracket is connected to the water sports rack mounting bolt. A water sports equipment rack mount is connected to the swivel bracket. The water sports equipment rack mount supports a water sports equipment rack adapted for holding various types of water sporting equipment. A sealed actuator housing is connected to the swivel bracket and houses an actuator, such as an electric, pneumatic or hydraulic actuator. The actuator is configured to drive the swivel bracket to rotate the water sports equipment rack.

Abstract: An apparatus, system and method for removing and treating contaminated materials on a bottom of a body of water and introducing growth packets to revitalize the treated bottom of the body of water. The structure may comprise a vessel with an open face. The vessel may be lowered down to the bottom of the body of water with the face facing down. As a result, the vessel and the bottom form an isolated space. The structure may comprise at least one agitating device(s) for stirring up the materials inside the vessel so as to form a mixture containing the sediment materials which in turn contain the contaminants. Multiple at least one pipe(s) may be coupled to the vessel for transporting the mixture out of the vessel for processing (filtering, treating with chemicals, etc.) so as to neutralize or eliminate the contaminants in the mixture. Then, the treated mixture can be returned to the inside of the vessel via the at least one pipe(s).

Abstract: The present disclosure provides a system and a method for efficiently converting the structure of a drilling floating platform into a structure for a production floating platform. A riser support module can be coupled to a topsides of the drilling floating platform and suspended below a moonpool or other opening through the topsides to support risers and their respective riser pull tubes, if any. The riser support module can be prebuilt and installed as a unit for example at a quayside.

Abstract: An apparatus for towing a water sports performer including a first leg, a second leg, a header, and a tow-line-attachment structure. Each of the first leg and second leg is adapted for attachment to one of the port side of a centerline of a boat or the starboard side of a centerline of a boat. The header is capable of assuming a plurality of different header lengths, and includes a first header portion, a second header portion, a housing, and a locking mechanism. The housing connects the first header portion and the second header portion. The housing includes a first receiver configured to receive a second end of the first header portion at a plurality of different positions. The locking mechanism is configured to secure the second end of the first header portion to the housing in one of the plurality of different positions to set the header length.

Abstract: A watch device includes a processor, a display and a memory. The memory includes instructions for establishing a network connection between the watch device and an electronic GPS mapping computer of a watercraft for transmitting, receiving or displaying data.

Abstract: A catamaran lifting apparatus is disclosed for lifting objects in a marine environment. The apparatus includes first and second vessels that are spaced apart during use. A first frame spans between the vessels. A second frame spans between the vessels. The frames are spaced apart and connected to the vessels in a configuration that spaces the vessels apart. The first frame connects to the first vessel with a universal joint and to the second vessel with a hinged connection. The second frame connects to the second vessel with a universal joint and to the first vessel with a hinged or pinned connection. The catamaran hull arrangement provides longitudinal flexibility in a quartering sea state due to the unique universal joint and hinge placement between the frames or trusses and the hulls or barges. Each of the frames extends upwardly in an inverted u-shape, providing a space under the frame and in between the barges that enables a marine vessel to be positioned in between the barges and under the frames.

Abstract: An unmanned underwater vehicle having one, some, or all of an integrated communication control fin, a ballast and trim control, a reusable trigger mechanism for a drop weight, and a visual hull display. Furthermore, associated methods are also provided.

Abstract: Disclosed herein is an inventive dual propeller assembly that can be manually or automatively assembled and includes a leading propeller, a torsion bushing, a thrust washer, a drive sleeve, and a trailing propeller. The propellers were coupled with an alignment system that did not require welding of the two propellers. The leading propeller includes a cylindrical hub and a plurality of blades that extend from an outer surface of the cylindrical hub. The trailing propeller includes a first cylindrical hub having a plurality of grooves, a second cylindrical hub having a cylindrical mount ring, and a conical profile formed between the first cylindrical hub and the second cylindrical hub. The outer surface of the first cylindrical hub is designed to mate with the inner surface of the cylindrical hub of the leading propeller. The trailing propeller is secured and aligned coaxially with the leading propeller. The trailing propeller can be effectively and consistently used with existing propellers.

Abstract: One embodiment of a deployable reversible camber sail system, based on a deployable shell (58) contained within a mast-sail assembly (11, 12) and supported and controlled by additional assemblies (13-15), is disclosed. The embodiment may be easily and quickly configured into the furled, feathered, port tack and starboard tack sail forms. In addition, this embodiment represents a highly efficient sail module which may be controlled by a single human operator or automated computer-based control system. Additional embodiments, utilizing assemblages of the first embodiment sail system module, are described.

Abstract: A power steering system for a watercraft includes an electromechanical rotary actuator mounted within a cylindrical housing. The electromechanical rotary actuator includes a motor and a gearing system. The housing, along with a stern bracket and an output flange, are sized and arranged to permit steering movements and trim/tilt movements of an outboard motor. The power steering system may include one or more of a redundant linear actuator, a trim/tilt mechanism, and a control system.

Abstract: A kit is provided which can be installed on a sailboat and used to selectively control the position of the tiller of the sailboat to allow the helmsman to leave the tiller unattended for a limited period of time.

Abstract: A system for supplying hydrogen gas to a lighter-than-air (LTA) vehicle includes a manifold having multiple vessels. Each vessel has a first chamber that is separated from a second chamber by a barrier. A trigger assembly integrated with the barrier allows a liquid to be combined with a reactant and a catalyst in the second chamber to form a chemical reaction to generate hydrogen gas. A pressure relief valve located on each vessel opens to allow the hydrogen gas to exit when a predetermined pressure is reached, and the hydrogen gas is supplied to the LTA vehicle connected to the manifold.

Abstract: A multi-axis aircraft with a wind resistant unit includes a fuselage having an upper face and a lower face. The fuselage includes a central axis passing through the upper face and the lower face. A plurality of rotors is mounted to the fuselage. Each rotor includes a rotating axis parallel to the central axis. A wind resistant unit includes a plurality of wind barriers disposed in a radial direction perpendicular to a reference axis. Each wind barrier includes a plurality of rods fixed by at least one fixing member. Two adjacent rods have a passage therebetween. Each rod includes an axis proximal end facing the reference axis and an axis remote end remote to the reference axis. Each wind barrier includes a coupling end and an airflow diversion end. The coupling end is fixed by at least one coupling member to the upper face of the fuselage.

Abstract: Systems and methods are provided for enforcing contours onto parts of an aircraft. One embodiment is a method for enforcing a contour onto aircraft parts. The method includes removably attaching segmented ring details to aircraft skin details, attaching stringers to skin details to create skin assemblies, positioning skin assemblies at a support structure defining a contour, and fastening frames to the skin assemblies to create a panel. The method also includes removably installing a spreader section onto the panel to complete assembly of a brace prior to removal of the panel, transporting the panel while the brace enforces the contour, attaching the brace to braces for other panels to form a barrel section of a fuselage for an aircraft while the brace enforces the contour, and removing the brace from the barrel section after the barrel section has been formed.

Abstract: Disclosed is a panel for an aircraft structure, including a laminated skin of layers of metal of which in each case two are joined together by a fibre-reinforced adhesive layer, as well as a laminated doubler of layers of metal and at least one fibre-reinforced adhesive layer in each case between two layers of metal, wherein the doubler has a smaller size of perimeter than the skin and is bonded to an outermost layer of metal of the laminated skin by a fibre-reinforced supplementary adhesive layer, with the feature that at least one part of the perimeter of the fibre-reinforced supplementary adhesive layer is staggered inwards relative to the corresponding perimeter of the doubler and that that part of the inwards-staggered perimeter of the fibre-reinforced supplementary adhesive layer is delimited by a glued edge. Also disclosed is a method for manufacturing such a panel.

Abstract: An aircraft includes a clearance between an opening and a door. The clearance communicates with a cavity and is oriented in a direction intersecting a flow direction of an air flow to the outside of the aircraft in flight. The aircraft further includes an upstream edge and an upstream outer surface situated in front of the clearance joined by a sharp edge with a bend radius of less than or equal to 1 mm, in order to limit the incidence of aerodynamic noise.

Abstract: Sound absorbers and airframe components comprising such sound absorbers are disclosed. In one embodiment, an airframe component comprises an aerodynamic surface (48) and a sound absorber (38). The sound absorber (38) comprises a perforated panel (40) having a front side exposed to an ambient environment outside of the airframe component and an opposite back side. The panel (40) comprises perforations extending through a thickness of the panel for permitting passage of sound waves therethrough. The sound absorber (38) also comprises a boundary surface spaced apart from the perforated panel. The boundary surface and the back side of the perforated panel (40) at least partially define a cavity in the airframe component for attenuating some of the sound waves entering the cavity via the perforations in the perforated panel (40).