Patent ID: 12208909

DETAILED DESCRIPTION

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.

Referring now to Prior ArtFIG.1, an aircraft10is shown that comprises a single engine12, two air intakes14, and a plenum16configured to mix and homogenize air from the two air intakes before feeding air to the engine12. The plenum16feature shown decreases recovered dynamic pressure and results in decreased engine power and efficiency.

Referring now toFIG.2, a top view of an aircraft100is shown according to this disclosure. The aircraft ofFIG.2does away with the use of a plenum but retains use of a single engine tiltrotor. As compared to the aircraft10, recovered dynamic pressure, engine power, and engine efficiency can be significantly increased by substitution of the plenum16feature with a more aerodynamically blended converging section. Key features of the converging section include smooth flow surfaces without abrupt changes in duct area and direction along flow path, with symmetric sections aligned to direct flow evenly to engine inlet compressor. These features significantly reduce the noted pressure losses associated with plenum16, and provide more even flow velocity and pressure distributions at radial and circumferential locations at the engine compressor inlet, necessary for meeting allowable compressor inlet distortions common with high mass flow, axial flow turbine engines.

In the embodiment shown, aircraft100is a tiltrotor having a laterally centered plane101that, when viewed from above, divides the aircraft100into a left portion and a right portion (or a port side and starboard side). However, in other embodiments, aircraft100may be any other type of aircraft (e.g. fixed-wing aircraft, vertical takeoff and landing (VTOL) aircraft, “manned” or “unmanned” drone, etc.). Aircraft100generally comprises a fuselage102and a stowable wing assembly104comprising a selectively rotatable wing body105and a plurality of wings106extending therefrom. Each wing106comprises a pylon108comprising a rotor assembly110having a plurality of rotor blades112coupled thereto. Each pylon108is selectively pivotable between a horizontal orientation and a vertical orientation with respect to the fuselage102and associated wing106to adjust the thrust angle and transition the aircraft100between an airplane mode and a helicopter mode. Accordingly, the airplane mode is associated with a more horizontally-oriented thrust angle and propelling the aircraft100forward in flight, while the helicopter mode is associated with a more vertically-oriented thrust angle and propelling the aircraft100to and from a landing area.

Aircraft100also comprises a drive component carried in the fuselage102. In the embodiment shown, the drive component comprises an engine120coupled to an engine reduction gearbox (“ERGB”)122comprising a retractable driveshaft124. However, in other embodiments, the drive component may comprise a direct-drive electric motor, a direct-drive engine, a motor and gearbox combination, or an engine and a redirection gearbox, each comprising a retractable driveshaft124. In the embodiment shown, operation of the engine120causes the retractable driveshaft124to rotate about its rotation axis126. The retractable driveshaft124is selectively extended and retracted axially along rotation axis126to engage and disengage from an auxiliary or mid-wing gearbox130disposed within the selectively rotatable wing body105of the wing assembly104. The mid-wing gearbox130is operatively coupled to an interconnect driveshaft132extending therefrom through each wing106to a pylon gearbox134disposed in each pylon108. Each pylon gearbox134is coupled to the associated rotor assemblies110through a rotor mast136. Thus, when the retractable driveshaft124is engaged with the mid-wing gearbox130, rotation of the retractable driveshaft124imparted by the engine120is transmitted through the mid-wing gearbox130to the interconnect driveshafts132and the rotor masts to impart rotation to the counter-rotating rotor assemblies110. Conversely, when the retractable driveshaft124is disengaged from the mid-wing gearbox130, rotation of the retractable driveshaft124will not impart rotation to the rotor assemblies110. As such, the retractable driveshaft124allows the engine120to operate to run pre-flight checks, provide electrical power, and/or provide functions of an auxiliary power unit (APU) without engaging the rotor assemblies110.

In some embodiments, aircraft100may also comprise a wing assembly rotation system140configured to selectively rotate the wing assembly104with respect to the fuselage102about stow axis142. Most notably, the stow axis142is offset from the rotation axis126of the retractable driveshaft124. More specifically, the stow axis142is displaced longitudinally along a length of the fuselage102with respect to the rotation axis126of the retractable driveshaft124. In some embodiments, the offset between the stow axis142and rotation axis126may be about twelve inches. The location of the rotation axis126is generally set by the location of the interconnect driveshafts132and/or the mid-wing gearbox130. The stow axis142is generally selected to center the wing assembly104over the fuselage102, thereby reducing the overall footprint of the aircraft100when the wing assembly104is fully rotated. Further, in some embodiments, offsetting the stow axis142towards a more forward portion of the wing assembly104may provide structural benefits, such as allowing rotation of the wing assembly104in a thicker, more structurally rigid portion of the wing assembly104. Additionally, as will be discussed further herein, it will be appreciated that since the retractable driveshaft124extends at least partially into the wing body105of the wing assembly104when the retractable driveshaft124is engaged with the mid-wing gearbox130, the retractable driveshaft124is configured to accommodate the misalignment of the retractable driveshaft124and the stow axis142by selectively disengaging from the mid-wing gearbox130. Accordingly, it will be appreciated that the gearbox122comprising the retractable driveshaft124, the mid-wing gearbox130, and the wing assembly rotation system140may be referred to collectively as a stow system150.

Referring now toFIG.3, a side view of the aircraft100ofFIG.2is shown according to this disclosure. Aircraft100is shown with the retractable driveshaft124engaged with the mid-wing gearbox130and wing assembly104configured in a flight position. As shown, the retractable driveshaft124is selectively extended vertically to engage the mid-wing gearbox130when the wing assembly104is configured in the flight position. Thus, when the retractable driveshaft124is engaged with the mid-wing gearbox130, rotational motion of the retractable driveshaft124imparted by the engine120is transferred through the mid-wing gearbox130to the interconnect driveshafts132and the rotor masts to impart rotation to the counter-rotating rotor assemblies110to selectively propel the aircraft100.

Referring now toFIG.4, a side view of the aircraft100ofFIG.2is shown according to this disclosure. Aircraft100is shown with the retractable driveshaft124disengaged with the mid-wing gearbox130and wing assembly104configured in a stowed position. As shown, the retractable driveshaft124is selectively retracted vertically to disengage the mid-wing gearbox130. After the retractable driveshaft is disengaged from the mid-wing gearbox130, the wing assembly104may be selectively rotated relative to the fuselage102about the stow axis142in a clockwise direction as viewed from the top of the aircraft100until the wing assembly104reaches the stowed position. In the stowed position, it will be appreciated that the retractable driveshaft124is misaligned from the mid-wing gearbox130. In some embodiments, the stowed configuration of the wing assembly104may be reached after the wing assembly104is rotated about ninety degrees. Furthermore, in some embodiments, it will be appreciated that the wing assembly104may be rotated relative to the fuselage102about the stow axis142in a counter-clockwise direction.

Referring now toFIGS.5A-5C, detailed side views of the stow system150of the aircraft100ofFIGS.2-4are shown according to this disclosure. More specifically,FIG.5Ashows the retractable driveshaft124engaged with the mid-wing gearbox130and the wing assembly104configured in the flight position,FIG.5Bshows the retractable driveshaft124disengaged from the mid-wing gearbox130and the wing assembly104configured in the flight position, andFIG.5Ashows the retractable driveshaft124disengaged from the mid-wing gearbox130and the wing assembly104rotated about the stow axis142and configured in the stowed position. It will be appreciated that the retractable driveshaft124and the mid-wing gearbox130comprise an interface designed to properly align splines125of the retractable driveshaft124and the mid-wing gearbox130when the retractable driveshaft124is being selectively extended to engage the mid-wing gearbox130.

In operation, the retractable driveshaft124is selectively extended and retracted to engage and disengage from, respectively, the mid-wing gearbox130disposed in the wing body105of the wing assembly104. The retractable driveshaft124may be actuated electrically, electro-mechanically, hydraulically, and/or mechanically. For example, in some embodiments, the retractable driveshaft124may be extended and retracted by a rack and pinion. However, in other embodiments, the retractable driveshaft124may be extended and retracted by a machine screw type system. When the retractable driveshaft124is engaged with the mid-wing gearbox130as shown inFIG.5A, the retractable driveshaft124may be selectively retracted to a retracted position as shown inFIG.5B. After the retractable driveshaft124is retracted, the wing assembly104may be selectively rotated relative to the fuselage102about the stow axis142until the wing assembly104reaches the stowed position as shown inFIG.5C. Once the stow system150of aircraft100is configured as shown inFIGS.4and5C, the aircraft100may be parked, stowed, and/or driven into an entrance of a hangar while reducing the overall footprint of the aircraft100, thereby allowing for more compact storage of aircraft100and increased storage capacity of multiple aircrafts100. Furthermore, from the stowed position shown inFIG.5C, the wing assembly104may be selectively rotated relative to the fuselage102about the stow axis142until the wing assembly104reaches the flight position as shown inFIG.5B. Thereafter, the retractable driveshaft124may be selectively extended to engage the mid-wing gearbox130as shown inFIGS.3and5A, where the aircraft100is configured for flight.

Referring toFIGS.2-4, the aircraft100further comprises an air intake system (AIS)200. To minimize these losses, AIS200has air intakes disposed as close to the engine as possible, minimizes bends and transitions along the air flow path. This is accomplished by using a dual intake system, symmetrically mounted on sides of fuselage, ahead of the wing, or at other suitable locations providing optimal routing of air flow path.FIG.2shows an embodiment for a single engine tiltrotor application. A plenum feature shown decreases recovered dynamic pressure and results in decreased engine power and efficiency. These losses can be significantly reduced by substitution of the plenum feature with a more aerodynamically blended converging section, as shown inFIG.3andFIG.4. Key features of the converging section include smooth flow surfaces without abrupt changes in duct area and direction along flow path, with symmetric sections aligned to direct flow evenly to engine inlet compressor. These features significantly reduce the noted pressure losses associated with plenum arrangement, and provide more even flow velocity and pressure distributions at radial and circumferential locations at the engine compressor inlet, necessary for meeting allowable compressor inlet distortions common with high mass flow, axial flow turbine engines.

In the embodiment described inFIGS.2-5, the intakes are symmetrically located on the sides of the fuselage, although can be mounted in other locations such as forward of the wing as shown inFIG.8.

The AIS200comprises a plurality of air inlets202that serve as entrances to ducts204. The ducts204are disposed at least partially within the fuselage102and join with each other at a crotch206so that the ducts204feed air into a combining section208located generally downstream relative to crotch206(and generally aft of the crotch206). The combining section208is configured to receive streamline air flow from the ducts204. The combining section208is also configured to allow the air received from the ducts204to continue flowing in a streamline manner (as opposed to turbulent) from the crotch206to an output210of the combining section208. Air from the output210is subsequently fed to a compressor121of the engine120. The combining section208is sized and shaped so that the combining section208does not act like a plenum in any significant manner. In other words, the combining section208maintains the above-described streamline flow of air and outputs the streamline flow of air to the compressor121. By substantially maintaining the streamline flow of air, the AIS200can provide significant ram air benefits when the aircraft100is operated in a forward flight regime.

FIGS.6and7show more detailed views of the AIS200. In this embodiment, the ducts204begin at air inlets202which extend from and are offset from the fuselage102by a gap distance212. By providing the air inlets202in this offset manner, slower boundary layer air is not captured by the air inlets202during operation in the forward flight regime, thereby maximizing the ram air benefits provided by the AIS200. Additionally, and with additional reference toFIGS.2-4, it can be seen that a variety of components that do not form a portion of the AIS200are disposed laterally between the ducts204. For example, portions of the stow system150are disposed laterally between the ducts204. In this embodiment, the retractable driveshaft124is also disposed laterally between the ducts204. The ducts204generally follow paths that mirror each other about the laterally centered plane101, and the paths of the ducts204generally undulate primarily in a lateral manner without significant vertical changes. The air inlets202are generally disposed vertically so that they are at least partially at a same height as a portion of the engine120or the compressor121. In alternative embodiments, the air inlets can be provided substantially flush with the fuselage, thereby creating a lower pressure area that draws air into the ducts rather than scooping air from directly impinging air flows.

Referring now toFIGS.8-10, a tiltrotor aircraft300is shown that is substantially similar to aircraft100but does not comprise a stow system for rotation of the wings. The tiltrotor aircraft300comprises another embodiment of an AIS400. The AIS400is substantially similar to the AIS200insofar as it is substantially symmetrical about a laterally centered plane of the aircraft300and also provides streamline air flow output. The aircraft300comprises a fuselage302and an engine304disposed laterally centered and within the fuselage302. The AIS400comprises air inlets402, ducts404, a crotch406, a combining section408, and an outlet410that operate substantially similar to the similarly named components of AIS200. However, AIS400comprises ducts404that comprise a substantial variation in path both vertically and laterally. More specifically, the ducts404extend from a location well above the engine304and downward to the engine304. The air inlets402are located side by side at least partially above the fuselage302and at least partially above the wings306. This location of air inlets402can reduce visibility of the air inlets402from below which can be beneficial for preventing detection of the tiltrotor aircraft300in hostile environments.

Referring now toFIGS.11-19, an alternative embodiment of an AIS500is shown. The AIS500is configured to be disposed in an aircraft, such as aircraft100, in a manner substantially similar to the manner in which AIS200is disposed within aircraft100.FIG.11shows a front view of the MS500carried by an aircraft600. The aircraft600comprises a fuselage602, a wing604, and an engine606disposed in a substantially laterally centered location that is lower than the wing604. The engine606is configured to selectively rotate a shaft608. The AIS500is substantially similar to the AIS200, is substantially symmetrical about a laterally centered plane of the aircraft600, and similarly provides a streamline air flow output. The AIS500comprises air inlets502, ducts504, a crotch506, a combining section508, and an outlet510that operate substantially similar to the similarly named components of AIS200.

FIG.13shows the combining section508in greater detail and provides cross-sectional cutting lines B-B, C-C, D-D, E-E, and F-F, the associated cross-sectional views being provided asFIGS.14-18, respectively.FIG.13also includes generalized airflow streamlines512that indicate that air flows into the combining section508via two upstream unnotched leg portions514, which are denoted as being disposed along cutting line B-B and shown asFIG.14.FIG.14shows that the upstream unnotched leg portions514comprise a cross-sectional area having a substantially rectangular shape having rounded corners. The cross-sectional area of the upstream unnotched leg portions514comprise a length516, a width518shorter than the length516, and a cross-sectional area520substantially matched to an associated one of the ducts504.

FIG.13also shows that air flows from the upstream unnotched leg portions514to relatively downstream unnotched leg portions522, an example of which is denoted as being disposed along cutting line C-C and shown asFIG.15.FIG.15shows that the downstream unnotched leg portions522also comprise a substantially rectangular shape having rounded corners. The downstream unnotched leg portions can comprise a length524, a width526shorter than the length524, and a cross-sectional area528. Although the dimensions of the length524and width526and associated rounded corners may be different than the length516and width518and rounded corners of upstream unnotched leg portion514, respectively, the cross-sectional area528is substantially the same value as the cross-sectional area520.

FIG.13also shows that air flows from the downstream unnotched leg portions522to upstream notched leg portions530, an example of which is denoted as being disposed along cutting line D-D and shown asFIG.16.FIG.16shows that the upstream notched leg portions530comprise a relatively decreasingly rectangular shape as compared to upstream unnotched leg portion514and downstream unnotched leg portion522. In this embodiment, the upstream notched leg portions530can comprise a length532, a width534shorter than the length532, decreased radius corners536(relative to downstream unnotched portions522), increased radius corners538(relative to downstream unnotched portions522), a shallow notch540, and a cross-sectional area542. While the shape of the upstream notched leg portions530is different than both the upstream unnotched leg portions514shape and downstream unnotched leg portions522shape, the cross-sectional area542is substantially the same value as the cross-sectional areas520,528. The shallow notch540is present to accommodate the substantially cylindrical space544that extends generally forward from the engine606and which accommodates the shaft608and/or other components exterior to combining section508.

FIG.13also shows that air flows from the upstream notched leg portions530to downstream notched leg portions546, an example of which is denoted as being disposed along cutting line E-E and shown asFIG.17.FIG.17shows that the downstream notched leg portions546comprise a relatively increasingly partial annulus shape as compared to upstream notched leg portion530. In this embodiment, the downstream notched leg portions546comprise an at least partially C-shaped cross-sectional shape. The downstream notched leg portions546comprise a deep notch548that can accommodate a greater portion of the cylindrical space544(as compared to the shallow notch540). This increased accommodation of the cylindrical space544is necessary as the airflow is being increasingly laterally centrally directed as air flows toward the engine606. While the shape of the downstream notched leg portions546is different than the upstream unnotched leg portions514shape, the downstream unnotched leg portions522shape and the upstream notched leg portion530shape, the cross-sectional area550of the downstream notched leg portion is substantially the same value as the cross-sectional areas520,528,542.

As air moves downstream past the downstream notched leg portions546, the air of each of the mirrored lateral sides of the combining section508are combined into a single annular flow. Most generally, the airflow is transitioned from two separate but substantially equal flows of air into a single combined airflow about a fore-aft location associated with crotch506. In other words, airflow is generally provided in two streams forward of the crotch506and airflow is generally provided in a single combined annular stream aft of the crotch506.FIG.13shows that air flows from the downstream notched leg portions546to annular portions552, an example of which is denoted as being disposed along cutting line F-F and shown asFIG.18. While the annular portions552comprise different shapes relative to the portions514,522,530,546, the annular portions552generally comprise a cross-sectional area554substantially equal to two times the area520, two times the cross-sectional area528, two times the cross-sectional area542, and/or two times the cross-sectional area550. The annular portions552comprise form a central hole556sufficient to accommodate the cylindrical space544therethrough.

Referring now toFIG.19, a top cutaway view of the combining section508is shown.FIG.19is helpful in illustrating that the internal surfaces of the combining section508are aerodynamically shaped along the flow path to minimize variations in cross-sectional area to maintain smooth flow with minimal distortion and/or losses. In this embodiment, the cross-sectional area554is substantially the same area as an engine606air inlet and/or compressor of the engine606.

Referring now toFIGS.20and21, a top view and a side view, respectively, of a helicopter1000are shown. Helicopter1000has a rotor system1002with a plurality of rotor blades1004. The pitch of each rotor blade1004can be selectively controlled in order to selectively control direction, thrust, and lift of rotorcraft1000. Rotorcraft1000further includes a fuselage1006, and anti-torque system1008, and a tailboom1010. Rotorcraft1000further includes a landing gear system1012to provide ground support for the helicopter1000. The helicopter further comprises an engine1014connected to an air intake system1016. The air intake system1016is substantially similar to the AIS200at least insofar as it comprises air inlets1018, ducts1020, a crotch1022, a combining section1024, and an outlet1026that operate substantially similar to the similarly named components of AIS200. Portions of the rotor system1002are not shown inFIG.20so that the location of the AIS1016can be more clearly shown.

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, RI, 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.