Abstract: A floor structure is assembled from a plurality of extruded aluminum planks that extend laterally across the bed of a truck floor positioned on an undercarriage of a center beam and cross beams. The planks each have one or more ribs on their underside to strengthen the floor structure and provide a mechanical means for connecting adjacent planks together. Each plank is configured with a female end rib and a male end rib that interlock to restrain movement relative the adjacent planks in all directions except the lateral direction. Side rails are attached to the floor structure at the edges of the plank bed to prevent movement of the planks in the lateral direction.

Abstract: A drain valve (10), such as for a vehicle body structure, having: at least one frame (12); and at least one flap (14) secured to the at least one frame (12); at least one drain opening (13); wherein the at least one drain valve (10) is located within the at least one drain opening (13); wherein the at least one drain valve (10) has at least two positions: a sealed position, in which the at least one flap (14) prevents airflow; and an open position, in which the at least one flap (14) allows liquid to flow through the at least one drain valve (10).

Abstract: A utility vehicle including a cab assembly, a roof assembly, a windshield assembly, a rear window assembly, and two or more couplers attached to one or more ROPS members. The couplers are each aligned with and are releasably connected with a buckle insert attached to one or more of the roof assembly, windshield assembly, rear window assembly and doors of the cab assembly.

Abstract: An operator station suspension system including isolators, a butterfly crossbar and station connection locations located on the butterfly crossbar. The butterfly crossbar includes a central crossbar that extends laterally with forward extending arms rigidly connected at the left and right ends, and rearward extending arms rigidly connected at the left and right ends of the central crossbar. The butterfly crossbar couples to the operator station at the station connection locations with one of the isolators located between the butterfly crossbar and the operator station at each of the station connection locations to reduce noise and vibration. Each connection location can have a connection post, and the isolators can be ring-shaped to fit over the connection posts. The suspension system can also include shock dampers for vertical movement, control linkages for pitch motion, and/or stabilizer linkages for roll motion of the subframe structure relative to the chassis.

Abstract: A cab mounting apparatus for a vehicle includes a front mount connecting between a front side of a cab and a chassis. A rear mount connects between a rear side of the cab and the chassis. The front mount includes a stabilizer link disposed on a front side of the vehicle, a pair of front brackets individually fixed to the front side of the cab, and a pair of connecting arms individually connecting between respective ends of the stabilizer link and the respective front brackets. Each connecting arm is pivotally connected to each front bracket by a hinge member and a bush. The bush has a pair of stopper members disposed on both ends thereof. The bush and the pair of stopper members are integrated into a single unitary body.

Abstract: A rear spoiler device (8) for a vehicle comprises an air-guiding element (9, 19), which can be moved between a retracted base position and a driving position and has a guiding surface (9d) for aerodynamically extending the contour of an exterior surface (4, 3) of the vehicle in the driving position. The air-guiding element (9) has a contact edge (9c) extending in a lateral direction (y) for contacting the exterior surface (4) of the vehicle (1) in the driving position, wherein the rear spoiler device (8) can be mounted completely on a rear door of the vehicle, the air-guiding element (9, 19) being designed in a multi-layer manner.

Abstract: A rear spoiler device for a vehicle having at least one rear door includes an air guide element and an adjustment device configured to adjust the air guide element between a retracted base position that allows the rear door to be opened and an extended travel position configured to extend contours and guide air aerodynamically. The adjustment device is mounted in an articulated fashion on both a door-side joint and on a spoiler-side joint. The adjustment device has an intermediate joint provided between the door-side joint and the spoiler-side joint. An adjustment of the adjustment device from the base position to the travel position changes an intermediate joint angle formed at the intermediate joint.

Abstract: A drag reducing device for a vehicle body having a top wall and a door pivotably mounted to the rear of the body to open toward a side wall of the body, includes a wing sized and configured to turn airflow across the top wall of the body, the wing having a trailing edge and a proximal edge; and an assembly mounted to the door and configured for pivoting the wing so that the trailing edge of the wing is pivoted upward to a position above the top wall of the vehicle body when the door is open and for pivoting the wing so that the trailing edge of the wing is pivoted downward to a position below the top wall of the vehicle body when the door is closed. A break-away feature is provided that allows the wing to pivot downward when the deployed wing is contacted.

Abstract: Car having: a passenger compartment; a front hood, which is arranged before the passenger compartment; a rear hood, which is arranged behind the passenger compartment and has an upper surface; and an aerodynamic appendage, which is arranged in the area of the rear hood and on the upper surface of the rear hood. The aerodynamic appendage is provided with at least one movable element that is movably mounted to move between a lowered position, in which the movable element rests on the upper surface of the rear hood allowing an air flow only over the movable element, and a raised position, in which the movable element is raised and separated from the upper surface of the rear hood allowing an air flow both over the movable element and under the movable element.

Abstract: The elastic crawler (1) according to this disclosure comprises: an endless belt-like main body (2) having elasticity; a plurality of cores (3) embedded in a circumferential direction of the main body (2); a plurality of lugs (5) each being arranged in a manner protruding from an outer circumferential surface of the main body (2) and extending between the plurality of cores (3) adjacent in the circumferential direction of the main body (2); and an inner circumferential concavity (G1) formed at a position on an inner circumferential surface of the main body (2) overlapping, in a thickness direction of the main body (2), an outer circumferential concavity (G2) of each of the lugs (5). The elastic crawler device comprises: the elastic crawler (1); and a drive wheel, an idle wheel and a rolling wheel.

Abstract: A track for traction of an off-road vehicle such as an agricultural vehicle, a construction vehicle, a snowmobile, or another vehicle operable off-road. The track is mountable around a track-engaging assembly that includes a drive wheel for driving the track. The track is elastomeric to be flexible around the track-engaging assembly. The track includes an inner surface for facing the track-engaging assembly, a ground-engaging outer surface for engaging the ground, and a plurality of traction projections projecting from the ground-engaging outer surface. The track may have various features to enhance its traction, its floatation, and/or other aspects relating to use and performance of a track system of the vehicle.

Abstract: The lug bar includes a base, having a bar shape and made of a first metal, and an overlay, extending along the longitudinal direction of the base to cover a covered region as a part of the outer peripheral surface of the base. In an overlay edge portion corresponding to a boundary between the covered region and an exposed region other than the covered region of the surface of the base, the exposed region and the surface of the overlay are flush with each other to form a forged surface.

Abstract: This disclosure relates to a walking mechanism comprising a walking unit and a control unit, wherein the walking unit comprises a load frame, a mandrel is fixedly arranged on the load frame in a penetrating manner, an inner shaft sleeve sleeves the mandrel, and the inner shaft sleeve can rotate around the mandrel; at least two walking and supporting components are arranged on two sides of the load frame respectively; each walking and supporting component comprises a big gear wheel, an outer shaft sleeve and a supporting seat shaft sleeve; each big gear wheel fixedly sleeves the inner shaft sleeve, and a plurality of lock pin holes are formed in each big gear wheel; each outer shaft sleeve and the corresponding big gear wheel are arranged side by side, and each outer shaft sleeve movably sleeves the inner shaft sleeve.

Abstract: A quick-release mechanism enables the saddle of a cycling apparatus to be removed and installed to and from the cycling apparatus without the use of tools. The upper portion of the quick-release mechanism couples directly to the rails of the saddle. The lower portion of the quick-release saddle adapter is pivotally coupled to a saddle mounting post or secured to the cycling apparatus in place of the saddle by using the mechanism intended for mounting the cycling saddle. The quick-release mechanism may also be integrated into a standard cycling apparatus mount post.

Abstract: A seat frame for a motorcycle includes a plurality of aluminum parts manufactured with different manufacturing methods. A seat frame includes front members, middle members, and a rear member, the front members, the middle members, and the rear member being formed of aluminum. The rear member is formed by integral molding based on a gravity casting method. The rear member includes a pair of left and right rail portions, a front cross portion, a rear cross portion, and a plurality of attachment bosses for attaching other parts. The left and right rail portions each have an attachment portion to be connected to a rear end portion of corresponding one of the middle members provided on an end portion thereof on the front side in the vehicle longitudinal direction.

Abstract: A vehicle includes a fender, a storage compartment, and a first retaining wall. The fender has an inner surface, an outer surface, and a through hole connecting the inner surface and the outer surface. The storage compartment has a bottom plate. The bottom plate of the storage compartment is located at a side of the outer surface of the fender and at least covers the through hole. The fender is located below the storage compartment in a top-bottom direction of the vehicle. The first retaining wall is disposed on the outer surface of the fender and surrounds at least a portion of the through. A portion of the first retaining wall is closer to a front of the vehicle than the through hole in a front-rear direction of the vehicle.

Abstract: A canister structure for a saddle riding vehicle, including a canister connected with a fuel tank using a connection line, the canister adsorbing fuel vapor generated in the fuel tank, and a purge valve disposed in a path through which the fuel vapor is returned from the canister to an air intake system of an engine, includes an annular canister rubber that fits over an outer cylinder of the canister; a canister stay disposed on a vehicle body side; and an engagement portion disposed on the purge valve. In the canister structure, the canister rubber has, formed on an outer periphery thereof, an anterior-side mounting portion and a posterior-side mounting portion each having an insertion hole in which the canister stay is inserted and a purge valve mounting portion having an engagement portion insertion hole in which the engagement portion of the purge valve is inserted.

Abstract: A resin-made tank includes a mouthpiece capable of covering an inner peripheral surface, a distal end surface and an outer peripheral surface of the cylindrical filling portion, wherein a fuel tank body has a mouthpiece fixing portion to which a mouthpiece fixing jig is fixed. The mouthpiece has an annular skirt portion that covers the outer peripheral surface. The skirt portion has a fitting portion that is fitted on an upper portion of the outer peripheral surface on an upper portion of the skirt portion, and has a large diameter portion having a larger diameter than the fitting portion on a lower portion of the skirt portion. The mouthpiece has a stay portion extending radially outward of the mouthpiece from the large diameter portion, and a fixing hole, through which the mouthpiece fixing jig passes, is provided in the stay portion.

Abstract: Method and apparatus directed to cushioned traction pads for self-balancing vehicles. The method and apparatus is comprised of a front cushioned traction pad that has a top surface and a bottom surface; attaching the bottom surface of the front cushioned traction pad to a first deck portion disposed at a first end of a frame, the top surface of the front cushioned traction pad configured to receive a left or right foot of a rider; selecting a rear cushioned traction pad that has a top surface and a bottom surface. The top surface of the rear cushioned traction pad further has a rear kicktail extending integrally upwardly and rearwardly. The method and apparatus further include attaching the bottom surface of the rear cushioned traction pad to a second deck portion disposed at a second end of the frame for receiving the left or right foot of a rider.

Abstract: A scooter comprising a collapsible frame pivotally connected to a head stock assembly. A leg support is mounted on the frame. The head stock assembly comprises a handle bar stem having a wheel assembly attached at its lower end. There is a second wheel assembly attached to the frame assembly. The frame is collapsible to allow the scooter to move from an expanded, use position to a folded or collapsed position for storage.

Abstract: A foldable vehicle includes a front wheel frame having a front wheel pivotably connected thereto, the front wheel frame having a front circular opening for receiving the front wheel. The vehicle also has a rear wheel frame having a rear wheel pivotably connected thereto, the rear wheel frame having a rear circular opening for receiving the rear wheel. A pivot joint connects the front wheel frame and the rear wheel frame, with the front wheel frame and the rear wheel frame being pivotable against each other via the pivot joint. A front vertical support extends from the front wheel frame and has a handlebar assembly pivotably secured to the front vertical support, and a rear vertical support extends from the rear wheel frame and has a seat assembly removably secured to the rear vertical support.

Abstract: A balancing transporter is provided to mitigate occurrence of undesired sudden turning and falling of a user by virtue of various mechanisms that control the source/cause of mistakes and implement post-mistake remedies. Two adjusting members are operated by the user for turning control in a manner that interference between operations on the adjusting members and on handles is prevented. Maximum allowance of difference between wheel speeds is introduced to prevent sudden turns due to inappropriate operation. A rotational interlock unit mechanically enables the adjusting members to rotate in opposite directions to prevent sudden turns. Shock absorption and balance compensation mechanisms are introduced to keep the balancing transporter from tilting.

Abstract: A bicycle magnetism generation device and a disc brake adapter are configured to allow a rotation state of a bicycle wheel to be detected in a suitable manner. The bicycle magnetism generation device includes a magnetism generator generating magnetism. In a state where the disc brake rotor is coupled to a hub of a bicycle, the bicycle magnetism generation device is at least partially arrangeable between the disc brake rotor and the hub.

Abstract: A bicycle sprocket comprises a sprocket body, a plurality of sprocket teeth, an axially outward protuberance, and an axially inward protuberance. The axially outward protuberance is disposed on an outward facing side of the sprocket body to overlap at least partly with a bicycle chain engaging with a neighboring bicycle sprocket when viewed along a rotational center axis. The axially inward protuberance is disposed on an inward facing side of the sprocket body to overlap at least partly with the axially outward protuberance when viewed along the rotational center axis.

Abstract: Electronic shifting systems, mechanisms and methods of using and/or controlling the systems to operate a bicycle that allows front and rear gear changer mechanisms to be controlled with only two switches. The switches can be arranged so that each hand is only required to operate one switch to shift the bicycle.

Abstract: An expandable pontoon boat includes a center section, a first side section, and a second side section. First and second telescoping assemblies connect the first side section to the center section, and third and fourth telescoping assemblies connect the second side section to the center section. The telescoping assemblies may be extended and retracted to extend and retract the first and second side sections from the center section, thereby widening and narrowing the boat, respectively.

Abstract: The invention relates to a trim stabilizer device comprising a foil being structurally independent from the transom of a boat to which it is to be mounted and being tiltable around its transversal axis; a first actuator associated with the foil for tilting thereof; a adjusting arm associated with the foil, at one end, for making a vertical motion thereof relative to the transom, and at the other end, associated with a connecting member provided on the transom. The trim stabilizer device for boats comprises a second actuator for making a vertical motion by a non-manual force of the adjusting arm.

Abstract: The sidewall-suspended boat cooler is a cooler comprising a container and a lid. The container has an asymmetric layout comprising a front compartment and a rear descending wall overhang where the front compartment and the rear descending wall overhang are separated by a U-shaped space that mates with a gunwale or sidewall of a vessel. The lid is hingedly coupled to the rear of the container and a seal provides an airtight barrier between the container and the lid. The container and the lid are insulated to maintain the temperature of items stored within the cooler. Handles on the side of the cooler allow it to be conveniently carried. The sidewall-suspended boat cooler may further comprise an organizer on the exterior front wall and a cargo net the hangs adjacent the front of the container.

Abstract: A pop up storage system for a boat having an opening formed in a deck includes a cabinet beneath the opening in the deck. A drawer is mounted for vertical sliding movement into and out of the cabinet and defines a storage compartment movable between an open position and a closed position. A motion assistance arrangement extends between the cabinet and the drawer, and is configured for assisting in movement of the drawer relative to the cabinet between a raised position and a lowered position.

Abstract: A camera mount for a personal watercraft includes an elongated member that couples to a base mounted on the rear of the personal watercraft, behind the seat of the personal watercraft. The coupling point at the base allows the elongated member to pivot so that the top of the elongated member can move forward or rearward. The elongated member can be height-adjustable to raise or lower the camera attachment at the top of the elongated member. An extension arm rigidly couples the elongated member to the seat handle behind the seat of the personal watercraft to prevent the elongated member from shifting position while operating the personal watercraft.

Abstract: Wakeboat hull control systems are provided that can include a first accelerometer operatively associated with the hull of the wakeboat to measure the acceleration of the hull along a first axis; a second accelerometer operatively associated with the hull of the wakeboat to measure the acceleration of the hull along a second axis, the first axis being non-parallel to the second axis; and processing circuitry calculating the rotation of the hull of the wakeboat about a third axis based on the acquired measurements. Wakeboat hull control methods are provided that can include using the processing circuitry to calculate the rotation of the hull of the wakeboat about a third axis based on the acquired measurements.

Abstract: Provided is a system for protecting submerged components of a watercraft from collision with a submerged object or a floor of a body of water. The system includes a depth sensor configured to measure a water depth beneath the watercraft, an actuated mechanism configured to adjust a depth of at least one of the submerged components, and a controller in communication with the depth sensor and the actuated mechanism. The controller is operable to receive the measured water depth and control the actuated mechanism to adjust the depth of the at least one submerged component as a function of the measured water depth to prevent the at least one submerged component from colliding with the submerged object or floor of the body of water.

Abstract: Disclosed is a shut-off valve installed in an accommodation chamber regulating entry/exit of air. The shut-off valve includes: a body removably disposed in the accommodation chamber and having multiple air passage holes; a valve stem adapted to be moved vertically along a valve stem insertion hole formed in the body; a disc mounted on a disc engagement portion formed at a lower end of the valve stem to open/close at least one of the multiple air passage holes; a rotor disposed on an upper side of the body to vertically move the valve stem, the rotor being provided with an opening/closing indicator to check opening/closing of the shut-off valve outside the accommodation chamber, wherein the accommodation chamber has an upper wall, a lower wall, and a side wall, the body disposed passing through the upper wall and lower wall of the accommodation chamber, and the disc is located outside the accommodation chamber.

Abstract: A system and process is provided to deplete or remove moisture from wood coring in boats by piercing 20 a fiberglass outer skin; forming 30 bores or holes 200 in wood coring to form an exposed portion; processing ambient air 35 to create processed air; pumping or displacing 40 processed air into the bores or holes 200; penetrating 50 an exposed portion 80; with a sealant 100; and filling 60 the exposed portion 80 with a sealant 100.

Abstract: The diving mask includes a rigid frame, one or two lenses, and a face mask made of soft and elastically yielding material, the face mask having a front hollow projection for housing the nose of the diver and a rear perimeter profile applicable in an airtight way to the face of the diver so as to delimit an internal space between the mask and the face of the diver, the internal surface of said face mask being equipped with obstructing means obstructing a direct flow towards lenses of the air released from the diver nose.

Abstract: A back pack cinch for a strap securing a breathing tank, and an associated buoyancy compensation device worn by a driver are provided. The back pack cinch includes a cinch body. A cover is rotatably mounted to the cinch body. The cover has an open position and a closed position. The cover in the closed position is configured to tension a strap. A tab is rotatably mounted to the cinch body. The tab has an open position and a closed position. In the closed position, a portion of the strap is pressed against the serrated bearing surface by the tab to hold the portion of the strap in a fixed position.

Abstract: Underwater robotic systems are disclosed. In some instances, a robotic system may include a body, a flexible fin, and a rotatable mass associated with the body such that angular acceleration of the rotatable mass causes a reaction torque that rotates the body to deform the flexible fin to create thrust in water.

Abstract: An example trolling motor assembly that includes a shaft with an attached trolling motor and a foot pedal is provided herein. Deflection of the foot pedal causes a corresponding rotation in a direction the trolling motor is oriented. A feedback device is coupled with the foot pedal and configured to provide at least one of haptic, audible, or visual feedback to indicate to a user that rotation of the direction of the trolling motor has stalled or is about to stall. In some cases, the feedback device may be present in a handheld remote control device. Example determination that rotation of the direction of the trolling motor has stalled or is about to stall may occur when the user directed rotation input and the actual orientation of the trolling motor are out of sync and/or when a current draw from a motor for rotating the trolling motor is too large.

Abstract: The technology relates to a telescoping support structure which can be suspended between two objects. The telescoping support structure uses projections between adjacent tubular sections in order to prevent the adjacent tubular sections from falling away from one another. Although the telescoping support structure may be utilized in various different environments and circumstances, it may be of particular usefulness in the field of high-altitude ballooning. For instance, when used in a balloon system, the telescoping support structure may be suspended between two objects such as an upper payload structure and a lower payload structure. As another example, the telescoping support structure may be suspended between a balloon envelope and a payload which, in some examples, may include an upper and a lower payload structure.

Abstract: An aircraft includes a wing and a wing box. The wing is joined to the wing box at a side of body joint. The wing and the wing box each includes lower skin and a plurality of stringers on the skin. Ends of at least some of the stringers at the side of body joint have a web cutout and a base that is spanwise tapered to a knife edge at the skin.

Abstract: A vehicle body may have an internal skeleton, and a skin fabricated in-situ over the internal skeleton. The internal skeleton may be fabricated via a first additive manufacturing system. The skin may be fabricated via a second additive manufacturing system that is different from the first additive manufacturing system.

Abstract: A rotary wing aircraft with a fuselage that is equipped with at least one rail, comprising at least one sliding element, in particular a sliding door or a sliding window, that is slidably supported by the at least one rail, wherein the at least one sliding element is at least slidable along the at least one rail by means of an opening sliding movement into an opening movement direction from a fully closed position into a fully opened position, wherein a dampening unit is provided that dampens the opening sliding movement of the at least one sliding element upon reaching of the fully opened position.

Abstract: An integrated drain mast structure for use in draining fluids emanating from aircraft components, such as turbine engines and fuselages, for facilitating the detection of fluids leaking from said components. A self-supporting tube section including a plurality of generally aligned fluid passages each having a peripheral wall, at least a portion of which is common with at least a portion of another aligned adjacent fluid passage is connected to one or more of these aircraft components. An aerodynamic fairing includes a plurality of fairing fluid passages each connected to a respective fluid passage of the tube section and having respective fluid outlets. The tube section and fairing section can comprise a single integral structure.

Abstract: A floor panel connection system for attaching a floor panel to an airframe is disclosed. The connection system includes an offset flange insert comprising a base portion, a flange portion, and an interconnect portion. The base portion of the insert is configured to be received in a hole in an edge region of the floor panel and includes an opening that is sized to receive a fastener. The interconnect portion extends laterally from the base portion such that when the edge portion of the floor panel is overlapping a lateral edge portion of the airframe, the flange portion of the insert is beyond the lateral edge portion. The flange portion is also configured to be bonded to a bottom surface of the floor panel beyond the lateral edge portion of the airframe.

Abstract: A support structure for a propulsor blade includes at least one sleeve configured to support a root portion of the propulsor blade, the at least one sleeve fixedly attached to a surface of the root portion. The support structure also includes a preloading component configured to apply a residual compressive force to the at least one sleeve and the root portion of the propulsor blade, the residual compressive force configured to maintain an attachment of the at least one sleeve to the root portion. The propulsor blade and root portion may incorporate composite structural materials. The support structure and/or the preloading component increases the high cycle fatigue strength and bending capacity of blade retention assemblies (including, e.g., composite-to-metal joints) when subjected to high cycle bending loads under reduced centrifugal load conditions, thereby making further reductions in the size and weight of blade retention assemblies feasible.

Abstract: Disclosed herein is a hydraulic actuator system comprising a servoactuator including a hydraulic actuator and a control valve, wherein the supply of hydraulic fluid to the servoactuator from a fluid supply is adjustable through a control system based on feedback information relating to the servoactuator. The hydraulic actuator system may e.g. be used for controlling blade pitch in a variable pitch propeller system such as may be found on a turboprop aircraft or a ship.

Abstract: An aviation actuator assembly for various aviation servo and/or autopilot applications can include an actuator having an output shaft and a mechanical fuse for joining to the output shaft and another rotating body. The mechanical fuse can include a fuse body having a first connection point for joining to the output shaft, a second connection point for joining to the rotating body, and at least one channel defined in the fuse body. The first connection point and the second connection point are configured to be disposed in a line generally parallel to a common axis of rotation of the output shaft and the rotating body. The fuse body has a generally flat cross-sectional profile along its length between the first connection point and the second connection point, and the channel extends generally perpendicular to the length of the fuse body and narrows the cross-sectional profile.

Abstract: Method and apparatus for controlling the aerodynamics of an aircraft using an active flow control system is disclosed herein. In one example, the active flow control system includes an airframe and a plurality of fluidic oscillators. The airframe includes an inlet configured for flight speeds ranging from subsonic to hypersonic. The plurality of fluidic oscillators is mounted about a curvature of the airframe. Each fluidic oscillator includes a body and an integral nozzle coupled to the body. The body has an inflow portion and a narrow nozzle inlet formed opposite the inflow portion. The integral nozzle is coupled to the body by the narrow nozzle inlet. The narrow nozzle inlet forms a single fluid flow path from the inflow portion to the narrow nozzle inlet.

Abstract: A shock strut may comprise a strut cylinder, a strut piston operatively coupled to the strut cylinder, a shrink piston disposed at least partially within the strut cylinder, and a shrink chamber at least partially defined by the shrink piston. The shrink piston may comprise a shrink piston head, a sleeve extending from the shrink piston head, and a mechanical stop. A hydraulic fluid may be moved into the shrink chamber to compress the shrink piston and the strut piston into the strut cylinder to reduce an overall length of the shock strut.

Abstract: An aircraft includes an airframe; an extending tail; a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly; and a translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe; wherein a ratio of (i) the hub separation between the hub of the upper rotor assembly and the hub of the lower rotor assembly to (ii) a radius of the upper rotor assembly is between about 0.1 and about 0.135.