Patent Application
20210197955
Not applicable.
Not applicable.
Ducted-rotor aircraft have at least one ducted rotor for providing lift and propulsion forces. Each ducted rotor typically has internal structure that supports a motor of the aircraft and an aerodynamic exterior skin.
In this disclosure, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of this disclosure, the devices, members, apparatuses, etc. described herein may be positioned in any desired orientation. Thus, the use of terms such as “above,” “below,” “upper,” “lower,” or other like terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components, respectively, as the device described herein may be oriented in any desired direction.
It is desirable to minimize the number of separate components that make up the structure of a ducted-rotor aircraft, not only to limit the weight of the aircraft, but further to limit the number of joints that might be stressed during operation of the aircraft. Structural components are disclosed herein for use in aircraft such as ducted-rotor aircraft.
The position of ducts 107, and optionally the pitch of blades 111, can be selectively controlled to control direction, thrust, and lift of rotors 109. For example, ducts 107 are repositionable to convert aircraft 101 between a helicopter mode and an airplane mode. As shown in
In this embodiment, aircraft 101 is configured with four ducts 107, including two ducts 107a and 107b that form a forward pair of ducts and two ducts 107c and 107d that form an aft pair of ducts. Each duct 107 is rotatably coupled to fuselage 103 of aircraft 101 via a spindle. Ducts 107a and 107b are coupled directly to fuselage 103 by a first spindle 113. Ducts 107c and 107d are each independently coupled to a corresponding end of wing 105 via a respective spindle 115 (e.g., as seen in
Duct 107 further includes an inboard control vane 125a and an outboard control vane 125b, which are pivotally attached to inboard primary stator 121a and outboard primary stator 121b, respectively. Inboard control vane 125a and outboard control vane 125b are pivotable about a vane axis 127 that extends parallel to spindle axis 123. In this embodiment, inboard control vane 125a and outboard control vane 125b are configured to rotate together to facilitate yaw control, changes of direction, turning, etc. during flight of aircraft 101. It should be appreciated, however, that inboard control vane 125a and outboard control vane 125b may alternatively be configured to rotate independently from one another. It should further be appreciated that duct 107 is not limited to the illustrated configuration of inboard control vane 125a and outboard control vane 125b. For example, duct 107 may alternatively be configured with more or fewer control vanes, such as a single control vane that defines a continuous control surface. Duct 107 may include one or more sections of skin 129 that form an aerodynamic outer covering of duct 107, and that define an opening that extends through duct 107. As shown, hub 119 is located primarily aft of the opening.
Each rib 135 defines an upper end 141 and an opposed lower end 143. The upper end 141 of each rib 135 is configured to attach to forward spar 131, and the lower end 143 of each rib 135 is configured to attach to aft spar 133. As shown, ribs 135 may be configured with differing geometries relative to each other. For example, certain ones of ribs 135 may define one or more apertures that extend therethrough. It should be appreciated that duct 107 is not limited to the illustrated configuration of ribs 135. For example, duct 107 may be implemented with more or fewer ribs and/or with ribs having the same or different geometries as compared to ribs 135.
In this embodiment, duct 107 includes four fittings 137. Each fitting 137 is configured to couple to a second end of a corresponding stator 121. More specifically, duct 107 includes an inboard primary stator fitting 137a that is couplable to a second end of inboard primary stator 121a, an outboard primary stator fitting 137b that is couplable to a second end of outboard primary stator 121b, and two secondary stator fittings 137c that are couplable to respective second ends of secondary stators 121c. The opposed first end of each stator 121 is configured to be coupled to hub assembly 139.
In this embodiment, the structural members of duct 107 further include upper braces 145 and lower braces 147. Upper braces 145 are attached to forward spar 131 and are configured to support corresponding portions of skin 129. As shown, duct 107 includes eight upper braces 145 that are equally spaced apart around forward spar 131, attached to forward spar 131 at locations above every fitting 137 and at midpoints between adjacent fittings 137. Lower braces 147 are attached to aft spar 133 and are configured to support corresponding portions of skin 129. As shown, duct 107 includes four lower braces 147 that are spaced apart around aft spar 133, attached below corresponding upper braces 145. As shown, ribs 135 that are disposed between an upper brace 145 and a lower brace 147 may be wider than others of the plurality of ribs 135.
When assembled, as shown in
When ducts 107 of aircraft 101 are positioned as shown in
One or both of forward spar 131 and aft spar 133 may be constructed of composite material. In the instant disclosure, composite material preferably refers to plies of a fiber-reinforced plastic (FRP) composition that includes filament fibers, such as carbon fibers for example, embedded in a thermoset polymer matrix material such as a thermoplastic resin. Preferably the fibers within the plies are woven and the plies are pre-impregnated with resin. To illustrate, forward spar 131 and aft spar 133 may be constructed from one or more layered plies of carbon-fiber-reinforced plastic (CFRP). It should be appreciated that duct 107 is not limited to an implementation having two spars such as forward spar 131 and aft spar 133. For example, duct 107 may be alternatively implemented with more or fewer spars.
In this embodiment, duct 107 includes inboard primary stator fitting 137a, outboard primary stator fitting 137b, and a pair of secondary stator fittings 137c. Inboard primary stator fitting 137a, outboard primary stator fitting 137b, and secondary stator fittings 137c may be referred to as a system of fittings for installation in duct 107. Inboard primary stator fitting 137a and outboard primary stator fitting 137b may be referred to as first and second fittings of the system of fittings and secondary stator fittings 137c may be referred to as third and fourth fittings of the system of fittings.
As shown, each fitting 137 includes an attachment interface 159 that is configured to couple to structure of duct ring 149 and an attachment interface 161 that is configured to couple to a corresponding stator 121 of duct 107. For each fitting 137, attachment interface 159 is spaced from attachment interface 161 such that when fitting 137 is coupled to duct ring 149 and a corresponding stator 121, all or substantially all of stator 121 is located aft of trailing edge 155 of duct ring 149. It was observed that locating all or substantially all of stators 121 aft of trailing edge 155 of duct ring 149, thereby increasing a distance between blades 111 of rotor 109 and leading edges 157 of stators 121, decreases noise and increases vibrational stability of ducts 107.
For example, as shown in
Body 163 further defines a neck 175 that extends from attachment interface 159 to attachment interface 161. As shown, neck 175 is angled relative to attachment interface 159 and attachment interface 161. In this embodiment, attachment interface 159 is spaced apart from attachment interface 161 by neck 175.
Body 163 of inboard primary stator fitting 137a further defines an attachment interface 177 that is configured to at least partially receive a spindle of aircraft 101, such as spindle 113 or 115. As shown, attachment interface 177 comprises a tubular collar 179 that extends outward from body 163 along a second direction 181 that is opposite first direction 171. Collar 179 defines an aperture 183 that extends through body 163. As shown, aperture 183 opens to an interior of insert 173. Aperture 183 is configured to receive a portion of spindle 113 or 115. It follows that collar 179 is configured to receive a portion of spindle 113 or 115. Collar 179 may be configured to be mechanically fastened to spindle 113 and/or 115. For example, in this embodiment collar 179 has a plurality of apertures 185 that extend therethrough. Apertures 185 may be aligned with a complementary plurality of apertures of spindle 113 or 115 such that fasteners, for instance bolts, may be installed into the pluralities of apertures to removably secure duct 107 to spindle 113 and/or 115. It should be appreciated that collar 179 is not limited to the illustrated geometry, and more generally that attachment interface 177 is not limited to a collar.
Inboard primary stator 121a may include one or more structural members, in addition to inboard primary stator fitting 137a, that may be configured to facilitate coupling a spindle, such as spindle 113 or spindle 115, to inboard primary stator 121a, and thus to duct 107. For example, in this embodiment, inboard primary stator 121a includes a rib 191 that is spaced inward from inboard primary stator fitting 137a. In this regard, rib 191 is to central duct axis 151 than is inboard primary stator fitting 137a. Rib 191 defines an aperture 193 that extends therethrough and that aligns with aperture 183 when inboard primary stator fitting 137a is coupled to inboard primary stator 121a. Aperture 193 is configured to receive an end of a spindle, such as spindle 113 or spindle 115. It should be appreciated that inboard primary stator 121a is not limited to inboard primary stator fitting 137a and rib 191 to facilitate coupling a spindle to inboard primary stator 121a. For example, inboard primary stator 121a may be alternatively configured with one or more other structural members, in addition to or in lieu of one or both of inboard primary stator fitting 137a and rib 191, to facilitate coupling a spindle to inboard primary stator 121a.
Coupling duct 107 to a spindle that is coupled to fuselage 103 of aircraft 101, such as spindle 113 or spindle 115, establishes a primary load path from duct 107 to fuselage 103 via inboard primary stator 121a and the spindle. In this embodiment, coupling a spindle, such as spindle 113 or 115, to inboard primary stator 121a comprises disposing an end of the spindle into collar 179, and thus into aperture 183, of inboard primary stator fitting 137a and translating the spindle until the end thereof is received in aperture 193 of rib 191. When in an inserted position within apertures 183 and 193, the spindle may be secured to inboard primary stator 121a via fasteners, such as bolts, installed into apertures 185 of collar 179.
In this embodiment, outboard primary stator fitting 137b is configured similarly to inboard primary stator fitting 137a, omitting attachment interface 177. Additionally, secondary stator fittings 137c are configured similarly to outboard primary stator fitting 137b but have respective bodies that are narrower than that of outboard primary stator fitting 137b. Outboard primary stator fitting 137b and secondary stator fittings 137c define respective attachment interfaces (not shown) that are similar to attachment interfaces 159 and 161 of inboard primary stator fitting 137a.
At least one embodiment is disclosed, and variations, combinations, and/or modifications of the embodiment(s) and/or features of the embodiment(s) made by a person having ordinary skill in the art are within the scope of this disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of this disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, Rl, and an upper limit, Ru, is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=Rl+k*(Ru−Rl), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . 50 percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 95 percent, 98 percent, 99 percent, or 100 percent. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed.
Use of the term “optionally” with respect to any element of a claim means that the element is required, or alternatively, the element is not required, both alternatives being within the scope of the claim. Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Accordingly, the scope of protection is not limited by the description set out above but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present invention. Also, the phrases “at least one of A, B, and C” and “A and/or B and/or C” should each be interpreted to include only A, only B, only C, or any combination of A, B, and C.
