Patent Publication Number: US-2023159175-A1

Title: Aircraft propulsor and method for using said propulsor

Description:
BACKGROUND 
     1. Technical Field 
     This disclosure relates generally to electric and hybrid-electric aircraft, and more particularly to propulsion systems and methods for said aircraft. 
     2. Background Information 
     Electric and hybrid-electric propulsion systems for aircraft may be configured to convert electrical power into rotational energy to drive a propulsor, such as a propulsion fan or propeller (“prop”), to provide thrust for the aircraft. Aircraft including said propulsion systems may experience large disparities in thrust requirements during various flight conditions of the aircraft such as cruising, takeoff, landing, etc. Conventional steps to improve thrust capability to address all contemplated flight condition requirements have frequently been accompanied with reduced propulsive efficiency as well as increased weight and aerodynamic drag. Accordingly, there is a need for improved electric and hybrid-electric propulsion system architectures. 
     SUMMARY 
     It should be understood that any or all of the features or embodiments described herein can be used or combined in any combination with each and every other feature or embodiment described herein unless expressly noted otherwise. 
     According to an aspect of the present disclosure, a propulsor includes a propulsor body and a prop assembly in rotational communication with the propulsor body. The prop assembly includes a plurality of prop blades configured for rotation about an axial centerline of the propulsor. The plurality of prop blades are rotatable between a deployed position and a stowed position. The propulsor further includes at least one linkage having a first linkage end and a second linkage end. The first linkage end of the at least one linkage is rotatably mounted to the propulsor body and the second linkage end is configured to be rotatably mounted to an aircraft body. The propulsor further includes a first motor coupled to the at least one linkage and configured to rotate the at least one linkage relative to the propulsor body between a first rotational position and a second rotational position. 
     In any of the aspects or embodiments described above and herein, in the deployed position, the plurality of prop blades may extend in a first direction substantially radially outward from the axial centerline and, in the stowed position, the plurality of prop blades may extend in a second direction substantially axially with respect to the axial centerline. 
     In any of the aspects or embodiments described above and herein, the prop assembly may further include a hub configured for rotation about the axial centerline and each prop blade of the plurality of prop blades may be rotatably mounted to the hub. 
     In any of the aspects or embodiments described above and herein, the propulsor may further include a first shaft configured for rotation about the axial centerline and the first shaft may be mounted to the hub and configured to apply a rotational force to the hub. 
     In any of the aspects or embodiments described above and herein, the propulsor may further include a second shaft configured for rotation about the axial centerline and the second shaft may be configured to effect rotation of the plurality of prop blades between the deployed position and the stowed position. 
     In any of the aspects or embodiments described above and herein, each of the first shaft and the second shaft may be in rotational communication with the first motor and the first motor may be configured to selectively effect rotation of the first shaft and the second shaft about the axial centerline. 
     In any of the aspects or embodiments described above and herein, each of the first shaft and the second shaft may be in rotational communication with a second motor which is different than the first motor. The second motor may be configured to selectively effect rotation of the first shaft and the second shaft about the axial centerline. 
     According to another aspect of the present disclosure, an aircraft includes an aircraft body including an exterior surface and defining an interior cavity. The aircraft further includes at least one propulsor mounted to the aircraft body and moveable between a first propulsor position in which the at least one propulsor is located inside the interior cavity and a second propulsor position in which the at least one propulsor is at least partially disposed outside the interior cavity. The at least one propulsor includes a propulsor body and a prop assembly in rotational communication with the propulsor body. The prop assembly includes a plurality of prop blades configured for rotation about an axial centerline of the at least one propulsor. The plurality of prop blades are rotatable between a deployed position and a stowed position. The at least one propulsor further includes at least one linkage having a first linkage end and a second linkage end. The first linkage end of the at least one linkage is rotatably mounted to the propulsor body and the second linkage end is rotatably mounted to the aircraft body. The at least one propulsor further includes a first motor coupled to the at least one linkage and configured to rotate the at least one linkage relative to the propulsor body between a first rotational position corresponding with the first propulsor position and a second rotational position corresponding with the second propulsor position. 
     In any of the aspects or embodiments described above and herein, the aircraft may further include a gas turbine generator configured to provide electrical power for the at least one propulsor. 
     In any of the aspects or embodiments described above and herein, the aircraft may further include a main propulsor fixedly attached to the aircraft body. 
     In any of the aspects or embodiments described above and herein, the aircraft may further include an energy storage device configured to provide electrical power for the at least one propulsor. 
     In any of the aspects or embodiments described above and herein, the energy storage device may include one or both of a battery and a capacitor. 
     In any of the aspects or embodiments described above and herein, the aircraft may further include an energy storage device in electrical communication with the gas turbine generator. The energy storage device may be configured to provide electrical power for the at least one propulsor. 
     In any of the aspects or embodiments described above and herein, the at least one propulsor may be configured as a pusher prop. 
     According to another aspect of the present disclosure, a method for providing thrust for an aircraft includes deploying a propulsor from a propulsor stowed position within an interior cavity of an aircraft body to a propulsor deployed position in which at least a portion of the propulsor is disposed outside of the interior cavity. The method further includes rotating a plurality of prop blades of the propulsor from a blade stowed position to a blade deployed position in which the plurality of prop blades extend in a substantially radial direction relative to an axial centerline of the propulsor. The method further includes providing thrust for the aircraft by rotating the plurality of prop blades about the axial centerline. 
     In any of the aspects or embodiments described above and herein, the step of deploying the propulsor may be performed in response to a predetermined flight condition. 
     In any of the aspects or embodiments described above and herein, the predetermined flight condition may include one or both of a takeoff condition or a go-around condition. 
     In any of the aspects or embodiments described above and herein, the method may further include providing electrical power for the propulsor with an energy storage device. 
     In any of the aspects or embodiments described above and herein, the energy storage device may include one or both of a battery and a capacitor. 
     In any of the aspects or embodiments described above and herein, the propulsor may be configured as a pusher prop. 
     The present disclosure, and all its aspects, embodiments and advantages associated therewith will become more readily apparent in view of the detailed description provided below, including the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates a schematic plan view of an aircraft, in accordance with one or more embodiments of the present disclosure. 
         FIG.  2    illustrates perspective view of a propulsor including a plurality of prop blades in a stowed position, in accordance with one or more embodiments of the present disclosure. 
         FIG.  3    illustrates perspective view of the propulsor of  FIG.  2    including the plurality of prop blades in a deployed position, in accordance with one or more embodiments of the present disclosure. 
         FIG.  4    illustrates a side, cross-sectional view of the propulsor of  FIG.  2   , in accordance with one or more embodiments of the present disclosure. 
         FIG.  5    illustrates a side, cross-sectional view of a propulsor, in accordance with one or more embodiments of the present disclosure. 
         FIG.  6 A-C  illustrate side, cutaway views of an aircraft body having a propulsor mounted thereto, in accordance with one or more embodiments of the present disclosure. 
         FIG.  7    illustrates a flowchart depicting a method for providing thrust for an aircraft, in accordance with one or more embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    schematically illustrates an aircraft  20 . The aircraft  20  in the disclosed non-limiting embodiment is schematically illustrated having a “lifting body” configuration in which a fuselage  22  of the aircraft  20  produces lift. It should be appreciated, however, that any aircraft may benefit from aspects of the present disclosure and the configuration of the aircraft  20  should not be considered limiting. 
     The aircraft  20  generally includes the fuselage  22  and a propulsion system  24 . In some embodiments, the propulsion system  24  may be configured as a hybrid-electric propulsion system or as a fully electric propulsion system. As shown in  FIG.  1   , for example, the propulsion system  24  may include a generator  26  configured to generate electrical power for operation of the propulsion system  24 . In some embodiments, the generator  26  may be a gas turbine generator. However, the present disclosure is not limited to the use of a gas turbine generator and the propulsion system  24  according to the present disclosure may include other forms of electrical power generator such as, for example, by using a hydrogen fuel cell system or, in some embodiments, no form of electrical power generation for the propulsion system  24  at all. In some embodiments, the propulsion system  24  may additionally or alternatively include an energy storage device  28  for the storage of electrical energy for use by the propulsion system  24  and/or other electrical systems of the aircraft  20 . The energy storage device  28  may be configured, for example, as one or more batteries, capacitors, and/or other suitable energy storage devices. 
     As shown in  FIG.  1   , the propulsion system  24  further includes one or more propulsors, for example, at least one main propulsor  30  and at least one auxiliary propulsor  32 . As will be discussed in further detail, the main propulsor  30  may be fixedly mounted to the aircraft  20  and may be configured to provide all or the majority of the propulsive thrust throughout operation of the aircraft  20 . The main propulsor  30  may be an electric propulsor powered, for example, by the generator  26 . The auxiliary propulsor  32  may be movably mounted to the aircraft  20  and may be configured to provide additional propulsive thrust under certain predetermined flight conditions of the aircraft  20 .  FIG.  1    shows an exemplary arrangement of propulsion system  24  components including the generator  26 , the energy storage device  28 , main propulsors  30 , and auxiliary propulsors  32 , however, it should be understood that the propulsion system  24  of the present disclosure is not limited to the particular configuration, location, quantity, etc. of the propulsion system  24  components shown in  FIG.  1   . 
     Referring to  FIGS.  2 - 4   , an embodiment of the present disclosure auxiliary propulsor (hereinafter “propulsor”)  32  is illustrated. The propulsor  32  includes a propulsor body  34  forming an exterior housing the of propulsor  32  about an axial centerline  36  of the propulsor  32 . The propulsor body  34  extends between a forward end  38  and an aft end  40 . In some embodiments, the propulsor body  34  may include an aerodynamic fairing  42  located at the forward end  38  of the propulsor body  34 . The aerodynamic fairing  42  may be unitarily formed with the propulsor body  34  to define the forward end  38  of the propulsor body  34 . Alternatively, the aerodynamic fairing  42  may be detachably mounted to the downstream portions of the propulsor body  34  to allow access to internal components of the propulsor  32 . It should be understood that relative positional terms, such as “forward,” “aft,” “upper,” “lower,” “above,” “below,” “upstream,” downstream,” and the like are relative to the normal operational attitude of the propulsor  32  and should not be considered otherwise limiting. 
     The propulsor  32  includes a prop assembly  44  in rotational communication with the propulsor body  34 . The prop assembly  44  includes a hub  46 , configured for rotation about the axial centerline  36 , and a plurality of prop blades  48  mounted to the hub  46  and configured for rotation about the axial centerline  36  therewith. As shown in  FIGS.  2  and  3   , the plurality of prop blades  48  includes two prop blades  48 , however, the present disclosure is not limited to any particular number of prop blades and the plurality of prop blades  48  may include, for example, 2, 3, 4, 5, 6, etc. prop blades  48  mounted to the hub  46 . Each prop blade  48  of the plurality of prop blades  48  is rotatably mounted to the hub  46  and configured to rotate, relative to the hub  46 , between a stowed position and a deployed position. In the deployed position, the plurality of prop blades  48  extend in a direction substantially radially outward from the axial centerline  36  such that rotation of the hub  46  causes the plurality of prop blades  48  to generate thrust in an aftward direction. In the stowed position, the plurality of prop blades  48  extend in a direction substantially axially with respect to the axial centerline  36  such that the plurality of pro blades  48  extend in a generally forward direction from the hub  46 . Accordingly, the propulsor  32  may generally be configured as a “pusher prop” style propulsor. In the stowed position, the plurality of prop blades  48  may extend along and contact or otherwise be oriented proximate the propulsor body  34  so as to minimize the amount of stowage space required by the propulsor  32 . As used herein, the term “substantially” with respect to a direction or angular relationship refers to the stated direction or angular relationship +/−ten degrees. 
     The propulsor  32  includes a motor  50  mounted within the propulsor body  34 . The motor  50  may be configured as an electric motor configured to receive electrical power from the generator  26  and/or the energy storage device  28  of the propulsion system  24 , as previously described. The motor  50  may generally include a stator member  52  and a rotor member  54  retained within a motor housing  56 . The motor housing  56  may support one or more bearings  58  configured for rotational support of the rotor member  54 . 
     The propulsor  32  includes a first shaft  60  configured for rotation about the axial centerline  36 . The first shaft  60  is mounted to the hub  46  and configured to apply a rotational force from the motor  50  to the hub  46  to effect rotation of the plurality of prop blades  48  about the axial centerline  36 . In some embodiments, the first shaft  60  may be selectively coupled with the rotor member  54  of the motor  50  by a gearbox  62  and a clutch  64 . The gearbox  62  may include a planetary gearset, a star gearset, or the like. The clutch  64  may be configured as a centrifugal clutch, a hydraulicly actuated clutch, an electric-plate-based clutch, and the like, and the present disclosure is not limited to any particular clutch configuration. The clutch  64  may be selectively engaged with the rotor member  54  via the gearbox  62  to apply the rotational force from the motor  50  to the hub  46 . 
     The propulsor  32  includes a second shaft  66  configured for rotation about the axial centerline  36  of the propulsor  32  and extending along the axial centerline  36  between the prop assembly  44  and the motor  50 . The second shaft  66  may be coaxially oriented with the first shaft  60  about the axial centerline  36 . In some embodiments, the second shaft  66  may extend along the axial centerline  36  through the motor  50  and/or the first shaft  60  as shown, for example, in  FIG.  4   . The second shaft  66  is configured to translate axially along the axial centerline  36 , thereby effecting rotation of the plurality of prop blades  48  between the stowed position and deployed position. As shown in  FIG.  4   , the second shaft  66  may include a threaded portion  68  which may be selectively engaged by a clutch  70  to apply a rotational force from the motor  50  to the second shaft  66 , thereby translating the second shaft  66  along the axial centerline  36 . In some embodiments, the hub  46  may include one or more linear bearings positioned in contact with the second shaft  66  and configured to accommodate internal axial motion of the second shaft  66 . In some embodiments, the second shaft  66  may include a splined portion having one or more linear splines extending through the hub  46  such that the second shaft  66  may axially translate within the hub  46  but remain rotationally fixed relative to the hub  46 . 
     In some embodiments, the propulsor  32  may include a carrier  72  mounted to the aft end  40  of the propulsor body  34 . The carrier  72  may axially retain the hub  46  while allowing the hub  46  to rotate within the carrier  72  about the axial centerline  36 . Accordingly, the carrier  72  may include one or more bearings  74  configured to rotatably support the hub  46 . In some embodiments, the carrier  72  may be a unitary portion of the propulsor body  34 . 
     In some embodiments, the propulsor  32  may include one or more linkages  76 . As shown in  FIGS.  2 - 4   , the linkages  76  may be rotatably mounted to the propulsor body  34 , the carrier  72 , or one or more other components of the propulsor  32 . Each linkage  76  includes a first linkage end  78  rotatable mounted to the propulsor body  34 , for example, and a second linkage end  80  configured to be rotatably mounted to an aircraft body  82  (e.g., a fixed structure such as the fuselage  22 , a wing or nacelle of an aircraft, etc.). The linkages  76  are rotatable between a first rotational position and a second rotational position corresponding to a stowed position of the propulsor  32  and a deployed position of the propulsor  32 , respectively. Accordingly, the linkages  76  are configured to moveably mount the propulsor  32  to the aircraft body  82  and to allow the propulsor  32  to move, relative to the aircraft body  82 , between the stowed position and the deployed position. 
     In some embodiments, the propulsor  32  includes a motor  84 , independent of the motor  50 , configured to selectively effect rotation of the linkages  76  between the first linkage position and the second linkage position, and thereby selectively reposition the propulsor  32  between the stowed position and the deployed position. As shown in  FIG.  4   , the motor  84  may be configured as part of a ball screw linear actuator. The motor  84  may rotate a threaded shaft  86  having a ball screw nut  88  threadedly attached thereto. At least one drive linkage  90  may be connected to the ball screw nut  88  and a respective at least one linkage  76 , thereby cause the respective at least one linkage  76  to rotate between the first linkage position and the second linkage position in response to rotation of the threaded shaft  86  by the motor  84 . Each drive linkage  90  may be rotatably mounted to one or both of the ball screw nut  88  and a respective linkage  76 . However, it should be understood that the present disclosure is not limited to use of the above-described ball screw linear actuator to effect rotating of the linkages  76  and other mechanisms for positioning the propulsor  32  between the stowed position and the deployed position may be contemplated. 
     Referring to  FIG.  5   , in some embodiments, the propulsor  32  may include a gearbox  92 , instead of the motor  84 , to effect rotation of the linkages  76 . The gearbox  92  may be selectively engaged with the motor  50  using a clutch  94  which configured for selectively mechanical engagement with the motor  50  or the gearbox  62 . For example, with the clutch  94  engaged, the motor  50  may cause the threaded shaft  86  to rotate via the gearbox  92 , thereby rotating the linkages  76  as previously described. 
     Referring to  FIGS.  6 A-C  and  7 , aspects of the present disclosure include a method  700  for providing thrust for an aircraft, such as the aircraft  20 .  FIG.  6 A-C  illustrate side, cutaway views of the aircraft body  82  having the propulsor  32  mounted thereto in a stowed position (see  FIG.  6 A ), an intermediate position (see  FIG.  6 B ), and a deployed position (see  FIG.  6 C ). Initially, the propulsor  32  may be located within an interior cavity  96  defined by the aircraft body  82 . While the aircraft  20  is on the ground or during a flight condition of the aircraft  20  such as a cruising condition, the propulsor  32  may be stowed within the interior cavity  96 , for example, to reduce or eliminate any aerodynamic drag from the propulsor  32 . The aircraft body  82  includes an opening  98  extending between the interior cavity  96  and an exterior surface  100  of the aircraft body  82  to allow the propulsor  32  to be repositioned inside or outside of the interior cavity  96 . In some embodiments, the aircraft body  82  may include a cover device (not shown) which may cover the opening  98  when the propulsor  32  is in the stowed position inside the interior cavity  96 , thereby further reducing aerodynamic drag from the propulsor  32 . 
     In some flight conditions of the aircraft  20  including, but not limited to, a takeoff condition or a go-around condition prior to landing, it may be desirable for the aircraft  20  to have increased thrust above what may be provided by the main propulsor(s)  30 . Accordingly, Step  702  includes deploying the propulsor  32  by repositioning the propulsor  32  from the stowed position inside the interior cavity  96  to the deployed position, as discussed above. The propulsor  32  may be deployed in response to a predetermined flight condition in which it is known that additional thrust will be desired. Alternatively, the propulsor  32  may be selectively deployed during flight to increase available thrust. In the deployed position, all or at least a portion of the propulsor  32  (e.g., the plurality of prop blades  48 ) is located outside of the interior cavity  96  of the aircraft body  82 . As previously discussed, in some embodiments, the aircraft  20  may include a plurality of propulsors  32 . In some embodiments, all of the propulsors  32  of the aircraft  20  may be deployed during the flight condition to provide additional thrust for the aircraft  20 . In some embodiments, less than all of the propulsors  32  may be deployed, depending on how much additional thrust may be desired for the flight condition. 
     In Step  704 , the plurality of prop blades  48  are repositioned from the stowed position to the deployed position. In Step  706 , the motor  50  operates to effect rotation of the plurality of prop blades  48  about the axial centerline  36 , thereby providing additional thrust for the aircraft  20 . In some embodiments, Step  706  may include operating the motor  50  to effect reverse rotation of the prop blades  48  allowing the propulsor  32  to operate as a thrust reverser, for example, during a landing condition of the aircraft  20 . 
     In Step  708 , rotation of the prop blades  48  about the axial centerline  36  is secured once the additional thrust provided by the propulsor  32  is no longer desired. In Step  710 , the prop blades  48  are repositioned from the deployed position to the stowed position. In Step  712 , the propulsor  32  is repositioned from the deployed position to the stowed position within the interior cavity  96  defined by the aircraft body  82 . The Steps  708 ,  710 , and  712  may be performed for all deployed propulsors  32  or may be performed for a subset of the deployed propulsors  32 , as necessary to control the desired thrust for the aircraft  20 . 
     It is noted that various connections are set forth between elements in the preceding description and in the drawings. It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities. It is further noted that various method or process steps for embodiments of the present disclosure are described in the following description and drawings. The description may present the method and/or process steps as a particular sequence. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the description should not be construed as a limitation. 
     Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. 
     While various aspects of the present disclosure have been disclosed, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the present disclosure. For example, the present disclosure as described herein includes several aspects and embodiments that include particular features. Although these particular features may be described individually, it is within the scope of the present disclosure that some or all of these features may be combined with any one of the aspects and remain within the scope of the present disclosure. References to “various embodiments,” “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. Accordingly, the present disclosure is not to be restricted except in light of the attached claims and their equivalents.