Patent ID: 12240600

DETAILED DESCRIPTION

The following disclosure describes various illustrative embodiments and examples for implementing the features and functionality of the present disclosure. While particular components, arrangements, and/or features are described below in connection with various example embodiments, these are merely examples used to simplify the present disclosure and are not intended to be limiting. It will of course be appreciated that in the development of any actual embodiment, numerous implementation-specific decisions must be made to achieve the developer's specific goals, including compliance with system, business, and/or legal constraints, which may vary from one implementation to another. Moreover, it will be appreciated that, while such a development effort might be complex and time-consuming; it would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

In the Specification, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the present disclosure, the devices, components, members, apparatuses, etc. described herein may be positioned in any desired orientation. Thus, the use of terms such as “above”, “below”, “upper”, “lower”, “top”, “bottom”, or other similar 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 components described herein may be oriented in any desired direction. When used to describe a range of dimensions or other characteristics (e.g., time, pressure, temperature, length, width, etc.) of an element, operations, and/or conditions, the phrase “between X and Y” represents a range that includes X and Y.

Additionally, as referred to herein in this Specification, the terms “forward”, “aft”, “inboard”, and “outboard” may be used to describe relative relationship(s) between components and/or spatial orientation of aspect(s) of a component or components. The term “forward” may refer to a spatial direction that is closer to a front of an aircraft relative to another component or component aspect(s). The term “aft” may refer to a spatial direction that is closer to a rear of an aircraft relative to another component or component aspect(s). The term “inboard” may refer to a location of a component that is within the fuselage of an aircraft and/or a spatial direction that is closer to or along a centerline of the aircraft (wherein the centerline runs between the front and the rear of the aircraft) or other point of reference relative to another component or component aspect. The term “outboard” may refer to a location of a component that is outside the fuselage of an aircraft and/or a spatial direction that farther from the centerline of the aircraft or other point of reference relative to another component or component aspect.

Further, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Example embodiments that may be used to implement the features and functionality of this disclosure will now be described with more particular reference to the accompanying FIGURES.

Electric tiltrotor aircraft configurations described herein are characterized by tilting of the rotors on a wing. In various embodiments, the tiltrotor aircraft configuration rotates the rotor pylon at the side pylon of body, wing station inboard on the wing, or incorporating tiltwing elements with wing rotation as a whole. The degree of wing rotation with the pylon and placement of the axis of rotation relative to the wing are unique elements of embodiments described herein. Rotating a greater portion of the wing with the pylon reduces download of the rotor on the wing but makes transition of the wing from hovering flight to airplane mode flight more difficult, as the rotated portion of the wing will be stalled through a lot of transition increasing rotor power required in transition beyond that required for hover. Variation of wing rotation includes rotating only the pylon and none of the wing which make transition benign but increase power required in a hover to the downwash on the horizontal wing surfaces, rotating an outboard wing extension with the pylon which is a good compromise of download reduction and benign transition, rotating an inboard section of the wing with the pylon which or rotating the whole wing with the pylon both of which increase transition power required from a conventional tiltrotor but reduce download in hover. Pylon rotation actuation is effected through linear or rotary actuators forward, aft, or under the pylon are described herein.

FIGS.1A and1Billustrate an example tiltrotor aircraft100that is convertible between a VTOL or hover (also commonly referred to as helicopter) mode (shown inFIG.1A), which allows for vertical takeoff and landing, hovering, and low speed directional movement, and a cruise (also commonly referred to as airplane) mode (shown inFIG.1B), which allows for forward flight as well as horizontal takeoff and landing. Aircraft100includes a fuselage102, wing104, and a tail assembly106. In accordance with features of embodiments described herein, aircraft further includes propulsion systems112a,112b, proximate outboard ends of wing104. Wing tips114a,114b, are fixedly connected to outboard sides of propulsion systems112a,112b, as will be described below.

In the illustrated embodiment, each propulsion system112a,112b, includes a drive system housing comprising a pylon130a,130b, and a rotatable open rotor assembly132a,132b, comprising a plurality of rotor blades134a,134b, connected to a rotor mast and configured to rotate about a rotor axis136a,136b. As shown inFIGS.1A and1B, each rotor assembly132a,132b, includes three (3) rotor blades; however, it should be recognized that more or fewer blades may be implemented without departing from the spirit and the scope of the embodiments described. Rotation of rotor blades134a,134b, about rotor axis136a,136b, generates lift while operating in helicopter mode and thrust while operating in airplane mode. Each pylon130a,130b, may house one or more electric motors therein configured to produce rotational energy that drives the rotation of rotor assembly132a,132b. Alternatively, each pylon130a,130b, may house a gearbox therein that drives the rotation of rotor assembly132a,132b, wherein the gearbox receives rotational energy from a driveshaft.

In accordance with features of embodiments described herein, and as illustrated inFIGS.1A and1B, wing tips114a,114b, are fixedly attached to outboard sides of pylons130a,130b. Inboard sides of pylons130a,130b, are tiltably connected to outboard ends of wing104. In operation, wing tips114a,114b, together with propulsion systems112a,112b, tilt relative to wing104between a first position (FIG.1A), in which propulsion systems112a,112b, and wing tips114a,114b, are configured in a hover mode, and a second position (FIG.1B), in which propulsion systems112a,112b, and wing tips114a,114b, are configured in a cruise mode.

The position of rotor assemblies132a,132b, as well as the pitch of individual rotor blades134a,134b, can be selectively controlled in order to selectively control direction, thrust, and lift of aircraft100. As previously noted, propulsion systems112a,112b, are each convertible, relative to fuselage102, between a vertical position, as shown inFIG.1A, and a horizontal position, as shown inFIG.1B. Propulsion systems112a,112b, are in the vertical position during vertical takeoff and landing mode. Vertical takeoff and landing mode may be considered to include hover operations of aircraft100. Propulsion systems112a,112b, are in the horizontal position during forward flight mode, in which aircraft100is in forward flight. In forward flight mode, propulsion systems112a,112b, direct their respective thrusts in the aft direction to propel aircraft100forward. Aircraft100is operable to fly in all directions during the vertical takeoff and landing mode configuration ofFIG.1A, although faster forward flight is achievable while in the forward flight mode configuration ofFIG.1B. Propulsion systems112a,112b, including wing tips114a,114b, may be tiltable between the vertical and horizontal positions by actuators (not shown) that are tiltable in response to commands originating from a pilot and/or a flight control system. Typically, linear actuators may be used, which attach to the wing tip via a spindle in the outboard tip ribs and attach to a clevis on the pylon support which forms the structure of the pylon. The dual or triply-redundant electric or hydraulic actuator extends pushing the pylon up greater than 90 degrees. A gimbal on the lower wing attach spindle allows the angle of the actuator to rotate as the pylon moves from horizontal to vertical. In a more compact installation, a rotary actuator could be used. The actuator would be installed at a radius about the pylon spindle such that movement of the rotary actuator about the radius would drive the pylon rotation. Each of the propulsion systems112a,112b, may utilize a drive system comprising one or more electric motors and gearbox unit disposed within a respective pylon130a,130bas a power source to rotate the respective rotor assembly132a,132babout rotor axis136a,136bvia a rotor mast.

FIGS.2A and2Billustrate an example tiltrotor aircraft200that is convertible between a VTOL or hover (also commonly referred to as helicopter) mode (shown inFIG.2A), which allows for vertical takeoff and landing, hovering, and low speed directional movement, and a cruise (also commonly referred to as airplane) mode (shown inFIG.2B), which allows for forward flight as well as horizontal takeoff and landing. Aircraft200includes a fuselage202, wing204comprising wing segments202a,202b, tiltably connected to fuselage202, and a tail assembly206. In accordance with features of embodiments described herein, aircraft further includes propulsion systems212a,212b, integrated into respective wing segments204a,204b. Wing tips214a,214b, are fixedly connected to outboard sides of propulsion systems212a,212b.

Similar to the propulsion systems of aircraft100, each of propulsion systems212a,212b, may include a drive system housing comprising a pylon, and a rotatable open rotor assembly comprising a plurality of rotor blades connected to a rotor mast and configured to rotate about a rotor axis. As shown inFIGS.2A and2B, the rotor assembly of each of propulsion systems212a,212b, includes three (3) rotor blades; however, it should be recognized that more or fewer blades may be implemented without departing from the spirit and the scope of the embodiments described. Rotation of rotor assemblies of propulsion systems212a,212b, generates lift while the aircraft200is operating in helicopter mode and thrust while the aircraft200is operating in airplane mode.

In accordance with features of embodiments described herein, and as illustrated inFIGS.2A and2B, propulsion systems212a,212b(including wing tips214a,214b), and wing segments204a,204b, which tilt relative to fuselage202between a first position (FIG.2A), in which wing segments204a,204b, and propulsion systems212a,212b, are configured in a hover mode, and a second position (FIG.2B), in which wing segments204a,204b, and propulsion systems212a,212b, are configured in a cruise mode.

The position of wing segments204a,204b, rotor assemblies of propulsion systems212a,212b, as well as the pitch of individual rotor blades of all of the propulsion systems212a,212b, can be selectively controlled in order to selectively control direction, thrust, and lift of aircraft200. As previously noted, propulsion systems212a,212b, are each convertible, relative to fuselage202, between a vertical position, as shown inFIG.2A, and a horizontal position, as shown inFIG.2B. Propulsion systems212a,212b, are in the vertical position during vertical takeoff and landing mode. Vertical takeoff and landing mode may be considered to include hover operations of aircraft200. Propulsion systems212a,212b, are in the horizontal position during forward flight mode, in which aircraft200is in forward flight. In forward flight mode, propulsion systems212a,212b, direct their respective thrusts in the aft direction to propel aircraft200forward. Aircraft200is operable to fly in all directions during the vertical takeoff and landing mode configuration ofFIG.2A, although faster forward flight is achievable while in the forward flight mode configuration ofFIG.2B. Propulsion systems212a,212b, may be tiltable between the vertical and horizontal positions by actuators that are tiltable in response to commands originating from a pilot and/or a flight control system. A linear actuator (or a group of two or more linear actuators for redundancy) attached to the aft spar as shown inFIGS.7A and7Bor a spindle connecting the two wing boxes as shown inFIGS.6A and6Band pushing the trailing edge of the wing down are possible implementations.

FIGS.3A and3Billustrate an example tiltrotor aircraft300that is convertible between a VTOL or hover (also commonly referred to as helicopter) mode (shown inFIG.3A), which allows for vertical takeoff and landing, hovering, and low speed directional movement, and a cruise (also commonly referred to as airplane) mode (shown inFIG.3B), which allows for forward flight as well as horizontal takeoff and landing. Aircraft300includes a fuselage302, wing304, and tail assembly306. In accordance with features of embodiments described herein, aircraft further includes propulsion systems312a,312b. In the illustrated embodiment, propulsion systems312a,312b, are integrated into wing304proximate outboard ends thereof. Wing tips314a,314b, are fixedly connected to outboard sides of propulsion systems312a,312b.

Similar to the propulsion systems of aircraft100, each of propulsion systems312a,312bmay include a drive system housing comprising a pylon, and a rotatable open rotor assembly comprising a plurality of rotor blades connected to a rotor mast and configured to rotate about a rotor axis. As shown inFIGS.3A and3B, the rotor assembly of each of propulsion systems312a,312b, includes three (3) rotor blades; however, it should be recognized that more or fewer blades may be implemented without departing from the spirit and the scope of the embodiments described. Rotation of rotor assemblies of propulsion systems312a,312b, generates lift while the aircraft300is operating in helicopter mode and thrust while the aircraft300is operating in airplane mode.

In accordance with features of embodiments described herein, and as illustrated inFIGS.3A and3B, wing304, including propulsion systems312a,312b, and wing tips314a,314b, is tiltably connected to the fuselage302, and tilts relative to the fuselage between a first position (FIG.3A), in which wing304and propulsion systems312a,312b, are configured in a hover mode, and a second position (FIG.3B), in which wing304and propulsion systems312a,312b, are configured in a cruise mode.

The position of wing304and propulsion systems312a,312b, (including wing tips314a,314b) as well as the pitch of individual rotor blades of the propulsion systems312a,312b, can be selectively controlled in order to selectively control direction, thrust, and lift of aircraft300. As previously noted, wing304, including propulsion assemblies312a,312b, is convertible, relative to fuselage302, between a vertical position, as shown inFIG.3A, and a horizontal position, as shown inFIG.3B. Wing304and propulsion systems312a,312b, are in the vertical position during vertical takeoff and landing mode. Vertical takeoff and landing mode may be considered to include hover operations of aircraft300. Wing304and propulsion systems312a,312b, are in the horizontal position during forward flight mode, in which aircraft300is in forward flight. In forward flight mode, propulsion systems312a,312b, direct their respective thrusts in the aft direction to propel aircraft300forward. Aircraft300is operable to fly in all directions during the vertical takeoff and landing mode configuration ofFIG.3A, although faster forward flight is achievable while in the forward flight mode configuration ofFIG.3B. Wing304and propulsion systems312a,312b, may be tiltable between the vertical and horizontal positions by actuators (not shown) that are tiltable in response to commands originating from a pilot and/or a flight control system.FIGS.7A and7Billustrate a possible actuator arrangement in which a linear actuator tilts the aft spar of the wing box down and forward up in a streamlined arrangement. Actuator attach points can be varied to tailor mechanical advantage.

FIGS.4A and4Billustrate an example tiltrotor aircraft400that is convertible between a VTOL or hover (also commonly referred to as helicopter) mode (shown inFIG.4A), which allows for vertical takeoff and landing, hovering, and low speed directional movement, and a cruise (also commonly referred to as airplane) mode (shown inFIG.4B), which allows for forward flight as well as horizontal takeoff and landing. Aircraft400includes a fuselage402, wings404a,404b, booms406a,406b, connected to opposite sides of the fuselage402, and a tail assembly407. In accordance with features of embodiments described herein, aircraft further includes three pairs of propulsion systems, including a forward pair of boom-mounted propulsion systems408a,408b, an aft pair of boom-mounted propulsion systems410a,410b, and a pair of propulsion systems412a,412b. In the illustrated embodiment, propulsion systems412a,412b, are integrated into wings404a,404b, which are tiltably connected to outboard sides of booms406a,406b. Wing tips414a,414b, are fixedly connected to outboard sides of propulsion systems412a,412b. Propulsion systems408a,408b, are tiltably connected to the forward ends of wing booms404a,404b. Propulsion systems410a,410b, are mounted to top surfaces of booms406a,406b, proximate the aft end of the fuselage402.

Similar to the propulsion systems of aircraft100, each of propulsion systems408a,408b,410a,410b,412a, and412bmay include a drive system housing comprising a pylon, and a rotatable open rotor assembly comprising a plurality of rotor blades connected to a rotor mast and configured to rotate about a rotor axis. As shown inFIGS.4A and4B, the rotor assembly of each of propulsion systems408a,408b,412a,412b, includes five (5) rotor blades; however, it should be recognized that more or fewer blades may be implemented without departing from the spirit and the scope of the embodiments described. It should also be recognized that rotor assemblies of propulsion systems408a,408b, may include a different number of rotor blades than rotor assemblies of propulsion systems412a,412b. Rotation of rotor assemblies of propulsion systems408a,408b,412a, and412bgenerates lift while the aircraft400is operating in helicopter mode and thrust while the aircraft400is operating in airplane mode.

In the illustrated embodiment, each boom-mounted propulsion system410a,410b, includes a drive system housing comprising a pylon and a rotatable open rotor assembly comprising a plurality of rotor blades connected to a rotor mast and configured to rotate about a rotor axis. As shown inFIGS.4A and4B, each rotor assembly of propulsion systems410a,410b, includes two (2) rotor blades; however, it should be recognized that more or fewer blades may be implemented without departing from the spirit and the scope of the embodiments described. Rotation of rotor assemblies of propulsion systems410a,410b, generates lift while the aircraft400is operating in helicopter mode. It will be recognized that while rotor assemblies of propulsion systems410a,410b, are illustrated as being disposed above (i.e., on top of) booms406a,406b, they may alternatively be disposed below (i.e., on the underside of) booms.

In accordance with features of embodiments described herein, and as illustrated inFIGS.4A and4B, propulsion systems412a,412b, are integrated into wings404a,404b. Wings404a,404b, together with wing-mounted propulsion systems412a,412b(including wing extensions414a,414b), tilt relative to booms406a,406b, and fuselage402between a first position (FIG.4A), in which wings404a,404b, and propulsion systems412a,412b, are configured in a hover mode, and a second position (FIG.4B), in which wings404a,404b, and propulsion systems412a,412b, are configured in a cruise mode.

Forward propulsion systems408a,408b, are tiltably connected to forward ends of booms and tiltable between a first position (FIG.4A), in which propulsion systems408a,408b, are configured in a hover mode, and a second position (FIG.4B), in which propulsion systems408a,408b, are configured in a cruise mode. In accordance with features of embodiments described herein, aft propulsion systems410a,410b, are fixedly attached to booms406a,406b, aft of the wing404in hover mode and do not convert between hover mode (FIG.4A) and cruise mode (FIG.4B).

The position of wings404a,404b, including propulsion systems412a,412b, and propulsion systems408a,408b, as well as the pitch of individual rotor blades of all of the propulsion systems408a,408b,410a,410b,412a,412b, can be selectively controlled in order to selectively control direction, thrust, and lift of aircraft400. As previously noted, propulsion systems408a,408b,412a,412b, are each convertible, relative to fuselage402, between a vertical position, as shown inFIG.4A, and a horizontal position, as shown inFIG.4B. Propulsion systems408a,408b,412a,412b, are in the vertical position during vertical takeoff and landing mode. Vertical takeoff and landing mode may be considered to include hover operations of aircraft400. Propulsion systems408a,408b,412a,412b, are in the horizontal position during forward flight mode, in which aircraft400is in forward flight. In forward flight mode, propulsion systems408a,408b,412a,412b, direct their respective thrusts in the aft direction to propel aircraft400forward. Aircraft400is operable to fly in all directions during the vertical takeoff and landing mode configuration ofFIG.4A, although faster forward flight is achievable while in the forward flight mode configuration ofFIG.4B. Wings404a,404b, including propulsion systems412a,412b, and propulsion systems408a,408b, may be tiltable between the vertical and horizontal positions by actuators (not shown) that are tiltable in response to commands originating from a pilot and/or a flight control system. Linear actuators which attach to the wing via a spindle in the wing common to the wing ribs attach to a clevis on the side of the boom. The dual or triply-redundant electric or hydraulic actuator extends rotating the wing.

It should be noted that, although propulsion systems408a,408b, are shown and described as being tiltable between cruise and hover positions, those propulsion systems may be fixed in the hover positions, similarly to propulsion systems410a,410b.

FIGS.5A and5Billustrate an example tiltrotor aircraft500that is convertible between a VTOL or hover (also commonly referred to as helicopter) mode (shown inFIG.5A), which allows for vertical takeoff and landing, hovering, and low speed directional movement, and a cruise (also commonly referred to as airplane) mode (shown inFIG.5B), which allows for forward flight as well as horizontal takeoff and landing. Aircraft500includes a fuselage502, wings504a,504b, and a tail assembly506. In accordance with features of embodiments described herein, aircraft further includes a plurality of propulsion systems508a-508fintegrated into wings504a,504b.

Similar to the propulsion systems of aircraft100, each of propulsion systems508a-508fmay include a drive system housing comprising a pylon, and a rotatable open rotor assembly comprising a plurality of rotor blades connected to a rotor mast and configured to rotate about a rotor axis. As shown inFIGS.5A and5B, the rotor assembly of each of propulsion systems508a-508fincludes five (5) rotor blades; however, it should be recognized that more or fewer blades may be implemented without departing from the spirit and the scope of the embodiments described. It should also be recognized that rotor assemblies of propulsion systems508a-508fmay include different numbers of rotor blades. Still further, although six propulsion systems are illustrated, it will be recognized that more or fewer propulsion assemblies may be integrated into wings504a,504b. Rotation of one or more rotor assemblies of propulsion systems508a-508flift while the aircraft500is operating in helicopter mode and thrust while the aircraft500is operating in airplane mode.

In accordance with features of embodiments described herein, and as illustrated inFIGS.5A and5B, wings504a,504b, including propulsion systems508a-508f, are tiltably connected to the fuselage502, and tilt relative to the fuselage between a first position (FIG.53A), in which wings504a,504b, and propulsion systems508a-508f, are configured in a hover mode, and a second position (FIG.5B), in which wings504a,504b, and propulsion systems508a-508fare configured in a cruise mode.

The position of wings504a,504b, and rotor assemblies of propulsion systems508a-508f, as the pitch of individual rotor blades of all of the propulsion systems, can be selectively controlled in order to selectively control direction, thrust, and lift of aircraft500. As previously noted, wings504a,504b, including propulsion systems508a-508f, are convertible, relative to fuselage502, between a vertical position, as shown inFIG.5A, and a horizontal position, as shown inFIG.5B. Wings504a,504b, including propulsion systems508a-508f, are in the vertical position during vertical takeoff and landing mode. Vertical takeoff and landing mode may be considered to include hover operations of aircraft500. Wings504a,504b, including propulsion systems508a-508f, are in the horizontal position during forward flight mode, in which aircraft500is in forward flight. In forward flight mode, propulsion systems508a-508f, direct their respective thrusts in the aft direction to propel aircraft500forward. Aircraft500is operable to fly in all directions during the vertical takeoff and landing mode configuration ofFIG.5A, although faster forward flight is achievable while in the forward flight mode configuration ofFIG.5B. Wings504a,504b, and propulsion systems508a-508f, may be tiltable between the vertical and horizontal positions by actuators (not shown) in response to commands originating from a pilot and/or a flight control system. Each wing or the complete wing may be actuated with a linear or rotary actuary. Examples of a possible mechanism are shown inFIGS.6and7. In this case several motor driving several rotors/props are arranged along the rotating wing.

FIGS.6A and6Billustrate in greater detail a mechanism for actuating a wing of a spindle wing configuration, such as illustrated inFIGS.2A and2B, in accordance with details of embodiments described herein. In particular,FIGS.6A and6Bshow a linear actuator600actuating a spindle602connecting the left and right wing boxes604a,604b. Two or more linear actuators could also be used for redundancy.FIG.6Ashows the wings/wing boxes604a,604b, in horizontal mode.FIG.6Bshows the wings/wing boxes604a,604bin vertical mode. It will be noted that, although as shown inFIGS.6A and6B, actuator600is a linear actuator, in various implementations, one or more rotary or other type of actuator may advantageously be employed.

FIGS.7A and7Billustrate in greater detail a mechanism for actuating a wing of a carry-through wing configuration, such as illustrated inFIGS.3A and3B, in accordance with details of embodiments described herein. InFIGS.7A and7B, a linear actuator700actuates a carry through torque box702of a continuous wing including left and right wing boxes704a,704b. Two or more linear actuators could also be used for redundancy.FIG.7Ashows the wings/wing boxes704a,704b, in horizontal mode.FIG.7Bshows the wings/wing boxes704a,704bin vertical mode. It will be noted that, although as shown inFIGS.7A and7B, actuator700is a linear actuator, in various implementations, one or more rotary or other type of actuator may advantageously be employed.

FIGS.8A and8Billustrate an example tiltrotor aircraft800that is convertible between a VTOL or hover (also commonly referred to as helicopter) mode (shown inFIG.8A), which allows for vertical takeoff and landing, hovering, and low speed directional movement, and a cruise (also commonly referred to as airplane) mode (shown inFIG.8B), which allows for forward flight as well as horizontal takeoff and landing. Aircraft800includes a fuselage802, wing804, and booms806a,806b, connected to the wing on opposite sides of the fuselage802. In accordance with features of embodiments described herein, aircraft further includes three pairs of propulsion systems, including a first pair of boom-mounted propulsion systems808a,808b, a second pair of boom-mounted propulsion systems810a,810b, and a pair of wing-mounted propulsion systems812a,812b. In the illustrated embodiment, propulsion systems812a,812b, are tiltably connected to the leading edge of wing804at outboard ends thereof, while propulsion systems808a,808b, are tiltably connected to the forward end of booms806a,806binboard of propulsion systems812a,812b. Alternatively, propulsion systems808a,808b, may be tiltably connected to the forward edge of wing804inboard of propulsion systems812a,812b. Propulsion systems810a,810b, are mounted to bottom surfaces of booms806a,806b, proximate the aft end or aft of the fuselage802. Aircraft800further includes a tail assembly813at an aft end thereof.

Similar to the propulsion systems of aircraft100, each of propulsion systems808a,808b,810a,810b,812a, and812bmay include a drive system housing comprising a pylon, and a rotatable open rotor assembly comprising a plurality of rotor blades connected to a rotor mast and configured to rotate about a rotor axis. As shown inFIGS.8A and8B, the rotor assembly of each of propulsion systems808a,808b,812a,812b, includes five (5) rotor blades; however, it should be recognized that more or fewer blades may be implemented without departing from the spirit and the scope of the embodiments described. It should also be recognized that rotor assemblies of propulsion systems808a,808b, may include a different number of rotor blades than rotor assemblies of propulsion systems812a,812b. Rotation of rotor assemblies of propulsion systems808a,808b,812a, and812bgenerates lift while the aircraft800is operating in helicopter mode and thrust while the aircraft800is operating in airplane mode.

In the illustrated embodiment, each boom-mounted propulsion system810a,810b, includes a drive system housing comprising a pylon and a rotatable open rotor assembly comprising a plurality of rotor blades connected to a rotor mast and configured to rotate about a rotor axis. As shown inFIGS.8A and8B, each rotor assembly of propulsion systems810a,810b, includes two (2) rotor blades; however, it should be recognized that more or fewer blades may be implemented without departing from the spirit and the scope of the embodiments described. Rotation of rotor assemblies of propulsion systems810a,810b, generates lift while the aircraft800is operating in helicopter mode. It will be recognized that while rotor assemblies of propulsion systems810a,810b, are illustrated as being disposed below (i.e., on the underside of) booms806a,806b, they may alternatively be disposed above (i.e., on top of) booms.

In accordance with features of embodiments described herein, and as illustrated inFIGS.8A and8B, propulsion systems808a,808b,812a,812b, are tiltably connected to the wing804and tilt relative to wing between a first position (FIG.8A), in which propulsion systems808a,808b,812a,812b, are configured in a hover mode, and a second position (FIG.8B), in which propulsion systems808a,808b,812a,812b, are configured in a cruise mode. In accordance with features of embodiments described herein, aft propulsion systems810a,810b, are fixedly attached to booms806a,806b, aft of the wing804in hover mode and do not convert between hover mode (FIG.8A) and cruise mode (FIG.8B).

The position of rotor assemblies of propulsion systems808a,808b,812a,812b, as well as the pitch of individual rotor blades of all of the propulsion systems808a,808b,810a,810b,812a,812b, can be selectively controlled in order to selectively control direction, thrust, and lift of aircraft800. As previously noted, propulsion systems808a,808b,812a,812b, are each convertible, relative to fuselage802, between a vertical position, as shown inFIG.8A, and a horizontal position, as shown inFIG.8B. Propulsion systems808a,808b,812a,812b, are in the vertical position during vertical takeoff and landing mode. Vertical takeoff and landing mode may be considered to include hover operations of aircraft800. Propulsion systems808a,808b,812a,812b, are in the horizontal position during forward flight mode, in which aircraft800is in forward flight. In forward flight mode, propulsion systems808a,808b,812a,812b, direct their respective thrusts in the aft direction to propel aircraft800forward. Aircraft800is operable to fly in all directions during the vertical takeoff and landing mode configuration ofFIG.8A, although faster forward flight is achievable while in the forward flight mode configuration ofFIG.8B. Propulsion systems808a,808b,812a,812b, may be tiltable between the vertical and horizontal positions by actuators (not shown) that are tiltable in response to commands originating from a pilot and/or a flight control system.

It should be noted that, although propulsion systems808a,808b, are shown and described as being tiltable between cruise and hover positions, those propulsion systems may be fixed in the hover positions, similarly to propulsion systems810a,810b.

In accordance with features of embodiments described herein, in certain embodiments, when aircraft800is in cruise mode, rotor assemblies of propulsion systems810a,810b, may cease rotation. In embodiments in which propulsion systems808a,808b, are also fixed (i.e., do not convert between hover and cruise modes), rotor assemblies thereof may also cease rotation when aircraft800is in cruise mode. For rotors fixed in a hover or horizontal position, stopping the rotor when in transition to cruise flight on the wing reduces power requirements not contributing to forward flight. Drag is reduced by stopping the rotor such that only the tip presents frontal area. Propulsive efficiency of the remaining rotors is increased as the remaining rotors blade loading increases in cruise in comparison to power lost as a function of rotating the blade.

FIG.8Cillustrates in greater detail connection of one of forward propulsion systems of aircraft800(e.g., propulsion system808a) to forward end of one of booms of aircraft800(e.g., boom806a). InFIG.8, pylon806aincludes two clevises840a,840b, that engage opposite sides of a pylon support spindle842in a manner that enables on a bearing surface between horizontal and vertical (as shown inFIG.8C.

FIG.9illustrates a pylon configuration in which a rotor pylon900and rotation axis902are elevated above the wing torque box904. A pylon support spindle906is engaged on opposite sides thereof by bearing surface of clevises908a,908b. A linear actuator (not shown inFIG.9) attached to a spindle (not shown inFIG.9) in the wing torque box904and to the pylon support906actuates the pylon900between horizontal (as shown inFIG.9) and vertical orientations.

FIG.10illustrates a drive system1000that may be deployed in any of the propulsion systems described hereinabove. As shown inFIG.10drive system1000includes multiple electric motors1002for providing rotational energy to a rotor assembly1004via a gearbox1006.

FIG.11illustrates a drive system1100that may be deployed in any of the propulsion systems described hereinabove. As shown inFIG.11, drive system1100includes a single electrical motor for providing rotational energy to a rotor assembly1102.

In accordance with features of embodiments described herein, the drive system (such as drive system1000or1100) for a rotor assembly may tilt with the rotor assembly (e.g., located in a rotating pylon or in a rotating portion of a pylon) or may be fixed (i.e., non-tilting). In embodiments in which the drive system is fixed, the drive system may be located in a fixed portion of a partially tilting pylon, in which case a gearbox is used to allow transmittal across the rotation, or in the fuselage with a driveshaft down the wing. In certain embodiments, there may be a drive assembly in the pylon and a drive shaft and a group of motors disposed within the fuselage to allow redundancy with a reduced number of motors.

The electric tiltrotor configurations described herein are characterized by tilting of the rotors on a wing. The tiltrotor configurations described herein rotate the rotor pylon at the side pylon of body, at a wing station inboard on the wing, or by incorporating tiltwing elements with wing rotation as a whole. The degree of wing rotation with the pylon and placement of the axis of rotation relative to the wing may be customized depending on the embodiment. Additionally, the number of motors and the manner in which the motors are arranged in a rotating or fixed pylon or inboard in the fuselage with a drive shaft extending through the wing to the rotor assembly may also be customized depending on the embodiment. Pylon rotation may be actuated using one or more linear and/or rotary actuators located forward of, behind, or beneath the pylon depending on the embodiment.

Various tilting rotor pylon embodiments include embodiments in which the entire pylon and outboard of the pylon rotates, the entire pylon (and outboard) and a portion of the inboard wing structure rotates, the entire pylon and the entire wing structure rotates (i.e., tiltwing), and a portion of the pylon rotates either in line with the pylon or above the wing structure. Additionally, the electric motor or motors may be located in the rotating pylon, in a rotating portion of the pylon or a fixed portion of the pylon with a gearbox to allow transmittal across the rotation, and/or in the fuselage with a drive shaft down the wing and appropriate gearboxes for driving the rotor assembly. Additionally, one or more motors could be located in the pylon and one or more motors could also be located in the fuselage with a down-wing drive shaft to allow redundancy with a reduced number of motors.

Embodiments described herein support both flapping rotor and rigid rotor/prop pylon rotation. The pylon rotates about an axis within the wing or above the wing. In various embodiments, none of the wing structure, a portion of the wing structure, or all of the wing structure may rotate with the pylon. One or more motors for driving a combining gearbox to drive rotors may be arrayed in the rotor pylon or in the fuselage with or without an interconnect between rotors. Linear or rotary actuators may be used to implement pylon rotation.

Tilting portions offer a tradeoff between stalled wing in transition and a download in hover. Rotating the wing or a portion of the wing with the pylon increases the area of the wing seeing a high angle of attack and encountering stall versus additional download of a non-rotated wing in hover. A wing extension beyond the pylon increase cruise performance.

It should be appreciated that aircraft illustrated herein, such as aircraft100, is merely illustrative of a variety of aircraft that can implement the embodiments disclosed herein. Indeed, the various embodiments of the electric drive system line replaceable unit described herein may be used on any aircraft that utilizes motors. Other aircraft implementations can include hybrid aircraft, tiltrotor aircraft, quad tiltrotor aircraft, unmanned aircraft, gyrocopters, airplanes, helicopters, commuter aircraft, electric aircraft, hybrid-electric aircraft, and the like. As such, those skilled in the art will recognize that the embodiments described herein for an electric drive system line replaceable unit can be integrated into a variety of aircraft configurations. It should be appreciated that even though aircraft are particularly well-suited to implement the embodiments of the present disclosure, non-aircraft vehicles and devices can also implement the embodiments.

The components of rotor assemblies described herein may comprise any materials suitable for use with an aircraft rotor. For example, rotor blades and other components may comprise carbon fiber, fiberglass, or aluminum; and rotor masts and other components may comprise steel or titanium.

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 the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the 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.

The diagrams in the FIGURES illustrate the architecture, functionality, and/or operation of possible implementations of various embodiments of the present disclosure. Although several embodiments have been illustrated and described in detail, numerous other changes, substitutions, variations, alterations, and/or modifications are possible without departing from the spirit and scope of the present disclosure, as defined by the appended claims. The particular embodiments described herein are illustrative only and may be modified and practiced in different but equivalent manners, as would be apparent to those of ordinary skill in the art having the benefit of the teachings herein. Those of ordinary skill in the art would appreciate that the present disclosure may be readily used as a basis for designing or modifying other embodiments for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. For example, certain embodiments may be implemented using more, less, and/or other components than those described herein. Moreover, in certain embodiments, some components may be implemented separately, consolidated into one or more integrated components, and/or omitted. Similarly, methods associated with certain embodiments may be implemented using more, less, and/or other steps than those described herein, and their steps may be performed in any suitable order.

Numerous other changes, substitutions, variations, alterations, and modifications may be ascertained to one of ordinary skill in the art and it is intended that the present disclosure encompass all such changes, substitutions, variations, alterations, and modifications as falling within the scope of the appended claims.

One or more advantages mentioned herein do not in any way suggest that any one of the embodiments described herein necessarily provides all the described advantages or that all the embodiments of the present disclosure necessarily provide any one of the described advantages. Note that in this Specification, references to various features included in “one embodiment”, “example embodiment”, “an embodiment”, “another embodiment”, “certain embodiments”, “some embodiments”, “various embodiments”, “other embodiments”, “alternative embodiment”, and the like are intended to mean that any such features are included in one or more embodiments of the present disclosure but may or may not necessarily be combined in the same embodiments.

As used herein, unless expressly stated to the contrary, use of the phrase “at least one of”, “one or more of” and “and/or” are open ended expressions that are both conjunctive and disjunctive in operation for any combination of named elements, conditions, or activities. For example, each of the expressions “at least one of X, Y and Z”, “at least one of X, Y or Z”, “one or more of X, Y and Z”, “one or more of X, Y or Z” and “A, B and/or C” can mean any of the following: 1) X, but not Y and not Z; 2) Y, but not X and not Z; 3) Z, but not X and not Y; 4) X and Y, but not Z; 5) X and Z, but not Y; 6) Y and Z, but not X; or 7) X, Y, and Z. Additionally, unless expressly stated to the contrary, the terms “first”, “second”, “third”, etc., are intended to distinguish the particular nouns (e.g., blade, rotor, element, device, condition, module, activity, operation, etc.) they modify. Unless expressly stated to the contrary, the use of these terms is not intended to indicate any type of order, rank, importance, temporal sequence, or hierarchy of the modified noun. For example, “first X” and “second X” are intended to designate two X elements that are not necessarily limited by any order, rank, importance, temporal sequence, or hierarchy of the two elements. As referred to herein, “at least one of”, “one or more of”, and the like can be represented using the “(s)” nomenclature (e.g., one or more element(s)).

In order to assist the United States Patent and Trademark Office (USPTO) and, additionally, any readers of any patent issued on this application in interpreting the claims appended hereto, Applicant wishes to note that the Applicant: (a) does not intend any of the appended claims to invoke paragraph (f) of 35 U.S.C. Section 112 as it exists on the date of the filing hereof unless the words “means for” or “step for” are specifically used in the particular claims; and (b) does not intend, by any statement in the Specification, to limit this disclosure in any way that is not otherwise reflected in the appended claims.