Blade pitch coupled to propulsion system tilt

Abstract

Embodiments provide a mechanism for coupling a rotor blade pitch to a propulsion system tilt angle in an aircraft and more particularly in an electric aircraft. A system may include a tiltable propulsion system configured to move between a first tilt angle and a second tilt angle, where the tiltable propulsion system includes a plurality of rotor blades each configured to move between a first pitch position and a second pitch position; a tilt mechanism coupled to the tiltable propulsion system and configured to move the tiltable propulsion system between a first tilt angle and a second tilt angle; a pitch mechanism coupled to one or more of the plurality of rotor blades and configured to move the one or more of the plurality of rotor blades between a first pitch position and a second pitch position; and an actuator configured to simultaneously operate both the tilt mechanism and the pitch mechanism.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 63 / 440,054, filed on January 19, 2023, and entitled “Blade Pitch Linked to Tilt,” the disclosure of which is incorporated herein by reference in its entirety for all purposes. Technical Field

[0002] The described embodiments generally relate to an aircraft having vertical takeoff and landing capabilities. In particular, the embodiments provide an electric aircraft having one or more tilt propulsion systems. Background Art

[0003] Aircraft with tiltable propulsion systems typically include a tilt mechanism for tilting the propulsion system between different tilt angles. Some aircraft may include additional mechanisms specifically for changing the pitch of rotor blades coupled to the tiltable propulsion system. While these mechanisms provide useful functionality, each involves adding additional actuators and control functions, thereby increasing the components, weight, and complexity of the aircraft.

[0004] Embodiments address these and other problems individually and collectively. Summary of the Invention

[0005] The technology disclosed herein generally relates to an aircraft that includes a tiltable propulsion system. More specifically, the technology disclosed herein provides a mechanism for coupling the pitch position of the rotor blades of the propulsion system to the tilt angle of the propulsion system. According to various embodiments, an electric aircraft may include an electric vertical take-off and landing (VTOL) aircraft having multiple propulsion systems. One or more of the propulsion systems may be tiltable to provide thrust in various directions, such as a horizontal direction for forward flight and a vertical direction for vertical flight. An embodiment provides a mechanism for automatically changing the pitch of the rotor blades in response to a change in the tilt angle of the propulsion system. The pitch position and the tilt angle can be linked in any suitable manner, and in some embodiments, a single actuator can be used to control both pitch and tilt. Various invention embodiments are described herein, including methods, processes, systems, devices, etc.

[0006] An embodiment provides a system comprising: a tiltable propulsion system configured to move between a first tilt angle and a second tilt angle, wherein the tiltable propulsion system comprises a plurality of rotor blades, each of the plurality of rotor blades configured to move between a first pitch position and a second pitch position; a tilt mechanism connected to the tiltable propulsion system and configured to move the tiltable propulsion system between the first tilt angle and the second tilt angle; a pitch mechanism connected to one or more of the plurality of rotor blades and configured to move one or more of the plurality of rotor blades between the first pitch position and the second pitch position; and an actuator configured to simultaneously operate both the tilt mechanism and the pitch mechanism.

[0007] According to further embodiments, the system further includes a coupling between the pitch mechanism and the tilt mechanism such that movement of the tiltable propulsion system by the tilt mechanism results in corresponding movement of one or more of the plurality of rotor blades by the pitch mechanism.

[0008] According to a further embodiment, the coupling between the pitch mechanism and the tilt mechanism is configured such that each tilt angle of the tiltable propulsion system results in a pitch position of one or more of the plurality of rotor blades.

[0009] According to a further embodiment, the first tilt angle results in a first pitch position and the second tilt angle results in a second pitch position.

[0010] According to further embodiments, the pitch mechanism moves one or more of the plurality of rotor blades between a first pitch position and a second pitch position as the tilt mechanism moves the tiltable propulsion system between a first tilt angle and a second tilt angle.

[0011] According to further embodiments, the coupling between the pitch mechanism and the tilt mechanism is configured to provide a non-linear relationship between a tilt angle of the tiltable propulsion system and a pitch position of one or more of the plurality of rotor blades.

[0012] According to further embodiments, when the tiltable propulsion system is set to a first tilt angle, the nonlinear relationship results in a relatively small change in the pitch position of one or more of the plurality of rotor blades in response to a change in the tilt angle, and wherein, when the tiltable propulsion system is set to a second tilt angle, the nonlinear relationship results in a relatively large change in the pitch position of one or more of the plurality of rotor blades in response to a change in the tilt angle.

[0013] According to a further embodiment, the system further comprises a coupling mechanism configured to provide a coupling between the pitch mechanism and the tilt mechanism, wherein the coupling mechanism is configured to convert a tilting motion caused by the tilt mechanism into a linear motion at the pitch mechanism, and wherein the pitch mechanism is configured to convert the linear motion into a rotational motion at one or more of the plurality of rotor blades.

[0014] According to a further embodiment, the system further comprises a support structure, the tiltable propulsion system being coupled to the support structure, wherein the coupling mechanism is connected to the support structure and the tiltable propulsion system.

[0015] According to a further embodiment, the coupling mechanism is not directly connected to the tilting mechanism.

[0016] According to a further embodiment, the coupling mechanism comprises a first pivot point offset from a second pivot point of the tilting mechanism.

[0017] According to a further embodiment, the coupling mechanism comprises a four-bar slider crank, and the pitch mechanism comprises a slider coupled to the four-bar slider crank.

[0018] According to a further embodiment, the actuator is a component of a tilt mechanism, and wherein the pitch mechanism is coupled to the tilt mechanism.

[0019] According to further embodiments, the pitch mechanism does not comprise a separate dedicated actuator.

[0020] According to a further embodiment, the first tilt angle corresponds to a vertical flight configuration and the second tilt angle corresponds to a forward flight configuration.

[0021] According to another embodiment, the system also includes an aircraft comprising: a fuselage; a pair of wings coupled to opposite sides of the fuselage; and a tiltable propulsion system, wherein the tiltable propulsion system is coupled to a first wing of the pair of wings.

[0022] According to another embodiment, the system also includes a control system configured to control the tilt mechanism and the pitch mechanism through an actuator, and configured to: operate the tilt mechanism to gradually move the tiltable propulsion system from the first tilt angle to a third tilt angle through a group of intermediate tilt angles; operate the tilt mechanism to pause the movement of the tiltable propulsion system when the third tilt angle is reached; and operate the tilt mechanism to move the tiltable propulsion system from the third tilt angle to the second tilt angle after the aircraft reaches a predetermined speed or a predetermined altitude.

[0023] According to a further embodiment, the first tilt angle corresponds to a vertical flight configuration, the second tilt angle corresponds to a forward flight configuration, and the third tilt angle is within 10 degrees of the second tilt angle.

[0024] According to a further embodiment, the system further comprises a connection between the pitch mechanism and the tilt mechanism, the connection being configured such that each tilt angle of the tiltable propulsion system results in a corresponding pitch position of one or more of the plurality of rotor blades, wherein a first tilt angle results in a first pitch position, a second tilt angle results in a second pitch position, and a third tilt angle results in a third pitch position, wherein the third pitch position is at least 3 degrees less than the second pitch position.

[0025] According to a further embodiment, the first pitch position corresponds to an acceleration pitch and the second pitch position corresponds to an efficiency pitch.

[0026] Additional details regarding embodiments of the invention can be found in the detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Various embodiments of the present invention are disclosed in the following detailed description and accompanying drawings. In the accompanying drawings, similar components or features may have the same reference numerals. In addition, various components of the same or similar type may be distinguished by following the reference numeral with a dash and a second reference numeral to distinguish between the similar components.

[0028] Figure 1A to Figure 1B Depicted are plan views of an exemplary aircraft having tilt fans in forward and vertical configurations, respectively, in accordance with an embodiment.

[0029] Figures 2A to 2B An example of a propulsion system having a pitch mechanism coupled to a tilt mechanism is shown in accordance with an embodiment.

[0030] Figures 3A to 3B Two different rotor blade pitch positions are illustrated in accordance with various embodiments.

[0031] Figures 4A to 4D Examples of movement of a pitch mechanism according to various embodiments are illustrated.

[0032] 5A to 5D Examples of movement of coupling mechanisms according to various embodiments are illustrated.

[0033] Figure 6 A graph illustrating an example of a non-linear relationship between tilt angle and pitch position according to an embodiment.

[0034] 7A to 7C An example of a biased pivot mechanism according to an embodiment is illustrated.

[0035] Figures 8A to 8B An example of a coupling mechanism in the form of an exemplary four-bar slider crank mechanism is illustrated in accordance with various embodiments.

[0036] 9A to 9D Illustration of a roller cam mechanism on a centerline according to various embodiments. DETAILED DESCRIPTION

[0037] The technology disclosed herein generally relates to an aircraft that includes a tiltable propulsion system. More specifically, the technology disclosed herein provides a mechanism for coupling the pitch position of the rotor blades of a propulsion system to the tilt angle of the propulsion system. According to various embodiments, an electric aircraft may include an electric vertical take-off and landing (VTOL) aircraft having multiple propulsion systems. One or more of the propulsion systems may be tiltable to provide thrust in various directions, such as a horizontal direction for forward flight and a vertical direction for vertical flight. An embodiment provides a mechanism for automatically changing the pitch of the rotor blades in response to a change in the tilt angle of the propulsion system. The pitch position and the tilt angle can be linked in any suitable manner, and in some embodiments, a single actuator can be used to control both pitch and tilt. Various invention embodiments are described herein, including methods, processes, systems, devices, etc.

[0038] Several illustrative embodiments will now be described with respect to the accompanying drawings, which form a part of this document. The subsequent description provides only (multiple) embodiments and is not intended to limit the scope, applicability or configuration of the present disclosure. On the contrary, the subsequent description of (multiple) embodiments will provide those skilled in the art with an enabling description for implementing one or more embodiments. It is understood that various changes can be made in the functions and arrangements of the elements without departing from the spirit and scope of the present disclosure. In the following description, for the purpose of explanation, specific details are set forth in order to provide a thorough understanding of certain inventive embodiments. However, it will be apparent that various embodiments can be practiced without these specific details. The drawings and description are not intended to be restrictive. The words "example" or "exemplary" are used herein to mean "used as an example, instance or illustration." Any embodiment or design described herein as "exemplary" or "example" is not necessarily to be interpreted as being preferred or advantageous over other embodiments or designs.

[0039] Figure 1A and Figure 1B A plan view of an exemplary aircraft 100 is depicted, according to an embodiment. Aircraft 100 may be any suitable type of aircraft, such as an airplane, helicopter, drone, or hybrid flying vehicle. In some embodiments, aircraft 100 may be capable of vertical takeoff and landing (VTOL). Aircraft 100 may be configured for human piloting, remote piloting, and / or autonomous flight.

[0040] In the example shown, the aircraft 100 includes a fuselage 104, which may include a cabin section (e.g., toward the nose) for carrying passengers and / or cargo. A pair of wings including a first wing 102 and a second wing 103 may be mounted on or otherwise attached to the fuselage 104. The pair of wings may be coupled to opposite sides of the fuselage and may take any suitable shape and configuration. For example, the pair of wings may be rectangular straight wings, tapered straight wings, circular or elliptical straight wings, swept wings, delta wings, or any other suitable type of wing. In some embodiments, the first wing 102 and the second wing 103 may be coupled to the fuselage 104 in a high wing configuration. That is, the first wing 102 and the second wing 103 may be mounted on an upper portion of the fuselage 104, such as Figure 1A to Figure 1B As shown in .

[0041] Aircraft 100 may also include support structures 106(A)-(F) that may be coupled to wings 102, 103. Figure 1A to Figure 1B As shown in , each of the support structures 106(A)-(F) may take the form of a boom, although embodiments include any other suitable structures. Figure 1A to Figure 1B Six support structures 106(A)-(F) are shown, with three support structures 106(A)-(F) disposed beneath each of the pair of wings 102, 103. The support structures 106(A)-(F) may be coupled to the undersides of the pair of wings and may include a forward portion extending forward beyond the wings and a rearward portion extending rearward of the wings.

[0042] In some embodiments, each of the support structures 106(A)-(F) is identical and, therefore, can be interchanged between locations on the wing. For example, a first support structure 106(A) closer to the fuselage can be interchanged with an adjacent second support structure 106(B) (e.g., the middle boom on the wing) or an additional third support structure 106(C) (e.g., the boom farthest from the fuselage). Propulsion system

[0043] Aircraft 100 may also include propulsion systems 101(A)-(L). Figure 1A to Figure 1B Twelve propulsion systems 101(A)-(L) are shown, but any suitable number of propulsion systems 101(A)-(L) may be included. The propulsion systems 101(A)-(L) may be coupled to the pair of wings 102, 103 and may be equally divided between the wings. In some embodiments, as Figure 1A to Figure 1BAs shown in FIG, one or more of the propulsion systems 101(A)-(L) may be mounted on support structures 106(A)-(F). For example, pairs of propulsion systems 101(A)-(L) may be mounted on opposite ends of respective support structures 106(A)-(F), with one propulsion system mounted forward of the wing and the other propulsion system mounted rearward of the wing. In other embodiments, one or more of the propulsion systems 101(A)-(L) may be directly coupled to the wing. The number of booms and / or propulsion systems may vary depending on the flight requirements and demands of the aircraft 100.

[0044] According to various embodiments, each of the propulsion systems 101(A)-(L) may be configured to provide thrust to the aircraft 100. Thrust from one or more of the propulsion systems 101(A)-(L) may be used to move, control, and / or stabilize the aircraft 100. The propulsion systems 101(A)-(L) may take the form of any suitable mechanism for providing thrust. In one example, the propulsion system may include a rotor (e.g., a fan). The propulsion system may also include a drive mechanism for the rotor, such as a dedicated electric motor (e.g., in the case of an electric vehicle).

[0045] The rotor may include any suitable number of rotor blades (e.g., 2 blades, 3 blades, 4 blades, 5 blades, 6 blades, 7 blades, or 8 blades). The rotor blades may have a predetermined pitch or a predetermined angle of attack. In some embodiments, all rotor blades may have the same pitch or the same angle of attack. In other embodiments, at least two rotor blades may have a pitch or angle of attack that is different from each other. The rotor blades may be equally or unequally spaced. The rotor may also include a hub. The rotor blades may be attached to the hub. In some embodiments, the rotor blades and the integral hub may be manufactured as a single piece. The hub provides a central structure to which the rotor blades are connected and, in some embodiments, is shaped to surround the motor.

[0046] In some embodiments, the motor portion is low-profile, allowing the entire motor to fit within the hub of the rotor, presenting low drag to the airflow during forward flight. The rotor can be attached to the rotating portion of the motor. The stationary portion of the motor can be attached to a support structure. In some embodiments, the motor can be a permanent magnet motor and can be controlled by an electronic motor controller. The electronic motor controller can send current to the motor in a precise sequence to allow the rotor to rotate at a desired speed or with a desired torque. Propulsion system orientation - vertical

[0047] According to various embodiments, one or more of the propulsion systems 101(A)-(L) may be positioned, oriented, and / or otherwise configured to provide thrust and / or movement to the aircraft 100 in a predefined direction. For example, one or more of the propulsion systems 101(A)-(L) may be configured to provide thrust upward in a vertical direction. Figure 1A As shown in FIG, these propulsion systems may include propulsion systems 101(D), 101(E), 101(F), 101(J), 101(K), and / or 101(L). A propulsion system configured to provide thrust in a vertical direction may also be referred to as a vertical fan or a lift fan, or may be referred to as a propulsion system having a lift orientation or a hover orientation. A vertical fan may be used to generate vertical thrust (e.g., lift) for takeoff, landing, hovering, stabilizing, and / or controlling aircraft 100.

[0048] The vertical direction may be defined relative to the body of aircraft 100. For example, the vertical direction may be the vertical axis or z-axis of the aircraft (e.g., a plumb line intersecting the zenith and perpendicular to the ground when aircraft 100 is stationary on the ground or hovering slightly above the ground). In some embodiments, the vertical direction may be perpendicular to the ground when aircraft 100 is stationary on the ground and / or hovering stably in a horizontal orientation slightly above the ground. If aircraft 100 tilts, the z-axis of the aircraft (and the vertical direction) may no longer be perpendicular to the ground. Vertical thrust may be thrust in the vertical direction (e.g., upward or downward).

[0049] Vertical thrust can be achieved by mounting the vertical fans and / or their corresponding support structures 106(A)-(F) such that the axis of rotation of each of the vertical fans is parallel to the vertical direction and / or orthogonal to the direction of forward flight. In other words, the vertical fans can be oriented such that their rotor blades rotate in a horizontal plane (e.g., a plane horizontal relative to the fuselage, or a plane defined by the x-axis and y-axis of the aircraft 100) and about a vertical axis (e.g., the z-axis of the aircraft 100). In some embodiments, the vertical fans can be configured such that each set of rotor blades rotates in the same plane. In other embodiments, the vertical fans can be configured such that one or more of the set of rotor blades rotate in different planes (e.g., parallel planes).

[0050] In other embodiments, some or all of the vertical fans are oriented at an angle so that on a single level, one or more vertical fans have rotor blades that do not rotate in a horizontal plane and, instead of providing pure vertical thrust, provide thrust in a direction angled relative to the vertical. However, in combination, the group of angled vertical fans can together provide a net thrust in the vertical direction. For example, a non-vertical thrust component provided by an angled vertical fan on the first wing 102 can be offset by an equal and opposite non-vertical thrust component provided by an oppositely angled vertical fan on the second wing 103.

[0051] In some embodiments, two adjacent vertical fans may have their blades mounted at opposite angles of attack so that their rotor blades spin in opposite directions. Adjacent vertical fans may refer to two vertical fans coupled to opposite ends of the same support structure 106(A) (e.g., 101A and 101D), or two vertical fans on different support structures (e.g., 101A and 101B), or two vertical fans on different wings (e.g., 101A and 101G).

[0052] According to various embodiments, a first subset of the vertical fans may spin in a first direction, and a second subset (e.g., the remaining portion) of the vertical fans may spin in a second direction opposite to the first direction. Configuring the vertical fans so that some spin in the first direction and others spin in the opposite second direction may advantageously cancel out any angular momentum generated by the spinning blades, allowing the aircraft 100 to hover in a stable manner without spinning.

[0053] Furthermore, when desired, a rotational movement (e.g., yaw) about the vertical axis of the aircraft 100 can be performed by temporarily reducing the spin rate of some or all of a first subset of vertical fans spinning in a first direction and / or by temporarily increasing the spin rate of a second subset of vertical fans spinning in a second direction, so that the total angular momentum generated by the spinning blades is not canceled. Thus, the aircraft 100 can rotate using the vertical fans without requiring another thrust source oriented in another direction. Propulsion System Orientation - Horizontal

[0054] According to various embodiments, one or more of the propulsion systems 101(A)-(L) may be configured to provide forward thrust in a horizontal direction. Figure 1AAs shown in FIG, these propulsion systems may include propulsion systems 101(A), 101(B), 101(C), 101(G), 101(H), and / or 101(I). A propulsion system configured to provide thrust in a horizontal direction may also be referred to as a horizontal fan or propeller, or may be referred to as a propulsion system with a forward flight orientation. A horizontal fan may be used to provide horizontal thrust for forward flight, climbing, descending, and / or cruising. Figure 1A to Figure 1B As shown in , two propulsion systems of the same type (eg, two vertical fans) or different types (eg, one vertical fan and one horizontal fan) may be mounted on each of the support structures 106 (A)-(F).

[0055] The horizontal direction may be defined relative to the body of aircraft 100. For example, the horizontal direction may be the forward axis or x-axis of the aircraft. In some embodiments, the horizontal direction may be parallel to the ground when aircraft 100 is stationary on the ground, hovering stably in a horizontal orientation slightly above the ground, and / or in forward flight. If aircraft 100 tilts, the x-axis (and the horizontal direction) of the aircraft may no longer be parallel to the ground. Horizontal thrust may be thrust in a horizontal direction (e.g., forward or backward).

[0056] Horizontal thrust (e.g., forward thrust) can be achieved by mounting the horizontal fans and / or their corresponding support structures 106(A)-(F) so that the axis of rotation of each of the horizontal fans is parallel to the horizontal direction and / or parallel to the direction of forward flight. In other words, the horizontal fans can be oriented so that their rotor blades rotate in a vertical plane (e.g., a plane defined by the z-axis and y-axis of the aircraft 100) and about a forward axis (e.g., the x-axis of the aircraft 100). In some embodiments, the horizontal fans can be configured so that each set of rotor blades rotates in the same plane. In other embodiments, the horizontal fans can be configured so that one or more of the set of rotor blades rotate in different parallel planes.

[0057] In some embodiments, the horizontal fan can be configured to have the ability to spin in either direction. As a result, the horizontal fan can be capable of providing reverse thrust. Reverse thrust can be used to move the aircraft 100 in a rearward direction (e.g., to exit a hangar area from a hovering position). In addition, reverse thrust can be used to reduce forward flight speed. For example, the reverse thrust from the horizontal fan can be used to replace flaps or as a supplement to flaps to slow down the aircraft 100 and / or bring the aircraft 100 into a stationary hover.

[0058] In some embodiments, the horizontal and vertical directions may be orthogonal to each other. Thus, the vertical fan and the horizontal fan may provide thrust in substantially orthogonal directions. In other embodiments, the vertical fan and the horizontal fan may provide thrust that is approximately orthogonal or nearly orthogonal, but not completely orthogonal. Separating the directional thrust into two independent types of components can advantageously simplify the control and design of the aircraft 100. In some embodiments, the horizontal and vertical fans may be operated, powered, and otherwise controlled independently of each other, thereby allowing thrust to be applied independently in orthogonal directions (e.g., thrust may be applied in different directions at the same time and at different times).

[0059] The combination of horizontal fans and wings 102, 103 can achieve both forward motion and lift. In some embodiments, it may be more efficient to utilize horizontal fans and wings 102, 103 rather than vertical fans to achieve vertical lift. Once aircraft 100 reaches a sufficient speed (e.g., a predetermined speed or cruising speed) such that the wings provide sufficient lift to aircraft 100, the vertical fans may no longer be needed to provide lift, and the vertical fans may temporarily cease operation. For example, the vertical fans may initially be active and generate vertical thrust to lift aircraft 100. Once aircraft 100 leaves the ground and / or is at a certain altitude, the horizontal fans may be activated and / or increase horizontal thrust so that aircraft 100 gains horizontal speed. The vertical fans may continue to provide vertical lift while the horizontal speed increases, because wings 102, 103 may not provide sufficient vertical lift until a predetermined speed (e.g., cruising speed) is reached. As the wings 102, 103 gradually provide more (e.g., an increasing amount) of vertical lift during increasing horizontal speeds, the vertical fans may eventually (or gradually) reduce their vertical thrust contribution. Later, as the aircraft 100 decelerates or returns to a hovering position, the vertical fans may reactivate and / or increase vertical thrust. Propulsion system orientation - fixed

[0060] According to various embodiments, one or more of the propulsion systems 101(A)-(L) may have a fixed orientation. For example, one or more of the propulsion systems 101(A)-(L) may be mounted in a fixed orientation relative to the corresponding wing 102 or 103, the corresponding support structure 106(A)-(F), and / or the aircraft 100. Although the rotor blades of the fixed propulsion system may rotate when activated, the orientation of the propulsion system housing and structure may not rotate relative to the aircraft 100. As a result, the fixed propulsion system may be configured to provide thrust in a constant direction relative to the aircraft 100. According to embodiments, the thrust direction and orientation of the fixed propulsion system relative to the aircraft 100 (e.g., the fuselage, wings, and / or support structure) may not change or move regardless of the current direction of activity and / or movement of the aircraft 100 (e.g., both forward flight and vertical flight).

[0061] In some embodiments, one or more vertical fans may have a fixed orientation. For example, one or more of propulsion systems 101(D), 101(E), 101(F), 101(J), 101(K), and / or 101(L) may have a fixed vertical orientation. These propulsion systems may be referred to as fixed vertical fans.

[0062] Furthermore, according to some embodiments, one or more of the horizontal fans may have a fixed orientation. For example, propulsion systems 101(A), 101(B), 101(C), 101(G), 101(H), and / or 101(I) may have a fixed horizontal orientation. These propulsion systems may be referred to as fixed horizontal fans.

[0063] In some embodiments, all of the propulsion systems 101 (A)-(L) may have a fixed orientation. As a result, the vertical and horizontal fans may be permanently configured to provide thrust in orthogonal (or substantially orthogonal) directions. Propulsion system orientation - tiltable

[0064] In other embodiments, one or more of the propulsion systems 101(A)-(L) may be configured to change orientation. For example, one or more of the propulsion systems 101(A)-(L) may be configured and / or mounted in a manner that allows the angle and orientation of the propulsion systems 101(A)-(L) to be tiltable relative to the corresponding wing 102 or 103, the corresponding support structure 106(A)-(F), and / or the aircraft 100. As a result, the tilting propulsion system (which may also be referred to as a tiltable propulsion system or a tilting fan) may be configured to provide thrust in more than one direction relative to the aircraft 100.

[0065] The tilt fans may be coupled to the respective support structures 106(A)-(F) via one or more tilt mechanisms comprising, for example, a motor and a coupling mechanism. The tilt mechanisms may comprise one or more components coupled to the tilt fans and the respective support structures 106(A)-(F), which may thereby enable a relative position and angle change between the tilt fans and the respective support structures 106(A)-(F). Depending on an embodiment, the tilt mechanisms may be controllable and / or configured to change or move the orientation and thrust direction of the tilt fans relative to the aircraft 100 (e.g., the fuselage, wings, and / or support structure) based on the current activity, demand, and / or direction of movement of the aircraft 100 (e.g., forward flight, vertical flight). The entire tilt fan assembly, including the hubcap and the group of rotor blades, may all tilt together.

[0066] As discussed above, propulsion systems 101(A), 101(B), 101(C), 101(G), 101(H), and / or 101(I) can take the form of fixed horizontal fans. However, in other embodiments, one or more of propulsion systems 101(A), 101(B), 101(C), 101(G), 101(H), and / or 101(I) can alternatively take the form of tilt fans. Such tilt fans can be configured to switch (e.g., rotate or tilt) between a horizontal orientation and a vertical orientation. The horizontal orientation can also be referred to as a horizontal direction, a forward flight configuration, a second tilt configuration, and / or a second tilt angle. The vertical orientation can also be referred to as a vertical direction, a vertical flight configuration, a first tilt configuration, and / or a first tilt angle. Figure 1A The tilt fan is shown currently set in a forward flight configuration (also called a second tilt configuration or a second tilt angle). Figure 1B The tilt fan is shown currently arranged in a vertical flight configuration (also referred to as a first tilt configuration or a first tilt angle).

[0067] like Figure 1B As shown in FIG, all propulsion systems 101(A)-(L) may have a vertical orientation. Some of these propulsion systems may be vertical fans with a fixed vertical orientation (e.g., the propulsion systems in the rear row positions at 101(D), 101(E), 101(F), 101(J), 101(K), and / or 101(L)), while others may be tilt fans that are currently and temporarily configured to have a vertical orientation or vertical flight configuration (e.g., the propulsion systems in the front row positions at 101(A), 101(B), 101(C), 101(G), 101(H), and / or 101(I)). The tilt fans may have an orientation that is the same as or similar to that of the vertical fans. Figure 1A The tilt fans are shown in a forward flight configuration (e.g., propulsion systems in a forward position at 101(A), 101(B), 101(C), 101(G), 101(H), and / or 101(I)).

[0068] Figures 2A to 2B A closer view of the propulsion system 101 configured to tilt is shown. The propulsion system 101 (also referred to as a tilt fan) can be configured to tilt through a predetermined range of tilt configurations, which may include, for example, Figure 2A The vertical flight structure 211 shown in FIG. Figure 2B , and / or any other suitable number of intermediate tilt angles between the vertical flight configuration 211 (eg, 90 degrees or approximately 90 degrees) and the forward flight configuration 212 (eg, 0 degrees or approximately 0 degrees).

[0069] The propulsion system 101 can be controlled to switch between tilt configurations to provide additional thrust in any appropriate direction depending on the current movement requirements of the aircraft. For example, during takeoff, landing, and / or hovering, the propulsion system 101 can be set to the vertical flight configuration 211 to provide additional vertical thrust. During forward cruise flight, the propulsion system 101 can be set to the forward flight configuration 212 to provide horizontal thrust. During phases of forward acceleration, deceleration, altitude gain, and / or altitude loss, the propulsion system 101 can be set to intermediate tilt angles and configurations to provide both horizontal and vertical thrust components.

[0070] Depending on the embodiment, the propulsion system 101 may be tilted gradually, iteratively, or otherwise through a plurality of different intermediate tilt angles based on the phase of flight and / or aircraft requirements. For example, during a forward acceleration and / or altitude gain phase of flight, the propulsion system 101 may be tilted gradually (e.g., 0.5 degrees at a time, 1 degree at a time, etc.) from vertical to horizontal as speed and / or altitude increase.

[0071] In some embodiments, the vertical flight configuration 211 may be the maximum tilt of the propulsion system 101, and the forward flight configuration 212 may be the minimum tilt of the propulsion system 101. In other embodiments, the propulsion system 101 may be capable of tilt angles and configurations exceeding the vertical flight configuration 211 (e.g., angled above vertical such that there is an opposing horizontal component) and / or below the forward flight configuration 212 (e.g., angled below horizontal such that there is a downward component).

[0072] Referring back to FIG1 , embodiments allow aircraft 100 to include any suitable combination and number of tilting fans, fixed horizontal fans, and / or fixed vertical fans. Furthermore, each type of fan may be located at any suitable location along wings 102, 103 and / or at any suitable support structure 106(A)-(F). The type of propulsion system at each location may be selected to enhance a number of flight characteristics, including forward thrust, vertical thrust, maneuverability, drag, and / or any suitable flight characteristic.

[0073] While tilt fans may provide the ability to increase thrust in a specific direction as needed, it may be beneficial to incorporate one or more propulsion systems with a fixed orientation in order to reduce weight, reduce moving parts, reduce possible failure points, and / or reduce maintenance issues. Propeller blade pitch

[0074] The rotor blades (also known as propeller blades) of the propulsion system 101 can be configured to have a certain blade pitch. The blade pitch of a rotor blade refers to the angle between the blade chord line and one of the rotational plane of the propeller hubcap, the aircraft body, or the propeller of the propulsion system. The blade pitch can be described as the ratio of the forward distance per revolution, assuming there is no slip. Typically, low pitch (also known as fine pitch) produces good low-speed acceleration and climb rate in an aircraft, while high pitch (also known as coarse pitch) optimizes high-speed performance and fuel economy.

[0075] According to an embodiment, one or more rotor blades of the propulsion system 101 may have an adjustable pitch setting (also known as a variable pitch position). Such a propulsion system may be referred to as a variable pitch propeller. In a variable pitch propeller, the blade pitch of one or more rotor blades can be adjusted during flight. Thus, the blade pitch can be adjusted based on the flight phase (such as takeoff, climb, or cruise) to optimize thrust and / or efficiency. For example, a small pitch setting that can provide greater thrust can be used during takeoff, acceleration, increasing altitude, and / or landing. A larger pitch that can provide better efficiency can be used for high-speed cruise flight. An example of a low pitch used during takeoff is approximately 15 degrees. An example of a high pitch used during cruise flight is approximately 40 degrees.

[0076] The amount of thrust generated by a rotor blade depends on the speed and angle of attack of the rotor blade. The effective angle of attack of a rotor blade decreases as airspeed increases. To maintain a constant effective angle of attack, or an optimal effective angle of attack, the blade pitch can be increased.

[0077] Any suitable mechanism may be included to enable pitch adjustment. For example, the rotor blades may be coupled to corresponding hubcaps via one or more pitch mechanisms including, for example, a motor and a coupling mechanism. Depending on the embodiment, the pitch mechanism may be controllable and / or configured to change or move the pitch position of the rotor blades relative to the hubcap (or other portion of the propulsion system) based on the current activity, demand, and / or direction of movement of the aircraft 100 (e.g., forward flight, vertical flight). As discussed in more detail below, in some embodiments, the pitch mechanism may be coupled to and / or combined with a tilt mechanism.

[0078] Figures 3A to 3B The propulsion system 101 is shown with rotor blades 250 having variable pitch positions. Rotor blades 250 may be configured to rotate through a predetermined range of pitch positions, which may include, for example, Figure 3A The first pitch position 380 shown in FIG. Figure 3B The second pitch position 390 is shown in FIG.

[0079] The first pitch position 380 can be used during the first phase of a flight such as vertical takeoff, landing, hovering, forward acceleration, increasing altitude, etc. (e.g., when the aircraft is in a vertical flight configuration). The first pitch position 380 can be referred to as a hovering pitch or an acceleration pitch. The first pitch position 380 can be any pitch suitable for hovering flight, takeoff, and / or acceleration. As an example, the first pitch position 380 can be any suitable pitch between approximately 5 degrees and approximately 25 degrees (e.g., 5 degrees, 10 degrees, 15 degrees, 18 degrees, 20 degrees, 23 degrees, 25 degrees).

[0080] The second pitch position 390 (e.g., 40 degrees) can be used during a second phase of flight, such as cruise flight (e.g., when the aircraft is in a forward flight configuration). This second pitch position 390 can be referred to as a cruise pitch or an efficiency pitch. The second pitch position 390 can be any pitch suitable for cruise forward flight (e.g., for efficient flight under cruise conditions). As an example, the second pitch position 390 can be any suitable pitch between about 30 degrees and about 50 degrees (e.g., 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees).

[0081] In some embodiments, first pitch position 380 may be a minimum pitch and second pitch position 390 may be a maximum pitch for example rotor blade 250, with other pitch positions existing between first pitch position 380 and second pitch position 390. In other embodiments, rotor blade 250 may be capable of achieving a pitch below first pitch position 380 and a pitch above second pitch position 390.

[0082] Referring back to FIG. 1 , as described above, one or more of the propulsion systems 101 (A)-(L) may be tilt fans that can be tilted between a forward flight configuration and a vertical flight configuration. Thus, in some embodiments, both the blade pitch of the rotor blades and the tilt angle of the tilt fans may be adjustable. Both the blade pitch and the tilt angle may be adjusted based on the aircraft's current flight phase or other mobility requirements. For example, during takeoff, one or more tilt fans may be configured to have a vertical flight configuration to provide vertical lift, and one or more sets of rotor blades may be configured to have low pitch. During cruise flight, one or more tilt fans may be configured to have a forward flight configuration to provide horizontal thrust, and one or more sets of rotor blades may be configured to have high pitch. There may be times when the configurations are paired differently. For example, before reaching cruise speed, one or more tilt fans may be configured to have a forward flight configuration or an intermediate tilt angle and configuration to provide horizontal thrust, while one or more sets of rotor blades may be configured to have low pitch to provide optimal acceleration. Once a certain predetermined speed and / or predetermined altitude is reached, the low pitch may be changed to a high pitch. Coupling rotor blade pitch to propulsion system tilt

[0083] According to various embodiments, the pitch mechanism may be coupled to and / or combined with the tilt mechanism. The pitch mechanism may be configured such that movement or change in the propulsion system tilt automatically results in a corresponding movement or change in the pitch of one or more rotor blades of the propulsion system.

[0084] Embodiments may couple the pitch mechanism to the tilt mechanism in any suitable manner. For example, a single actuator (e.g., a motor) may control both the tilt mechanism and the pitch mechanism. In some embodiments, the actuator of the tilt mechanism may be coupled to the pitch mechanism, and a separate, dedicated actuator for the pitch mechanism may be omitted, thereby reducing the number of actuators on the aircraft. The actuator may be directly linked to the pitch mechanism, or alternatively, the actuator may be indirectly coupled to the pitch mechanism through one or more other components (such as components of the tilt mechanism).

[0085] Figures 2A to 2B An example of a propulsion system 101 is shown having a pitch mechanism 230 coupled to a tilt mechanism 220. The propulsion system 101 may include a coupling mechanism 240 that may be configured to couple (e.g., directly or indirectly) the tilt mechanism 220 to the pitch mechanism 230. The tilt mechanism 220 may be referred to as a first mechanism, the pitch mechanism 230 may be referred to as a second mechanism, and the coupling mechanism 240 may be referred to as a third mechanism.

[0086] The angular motion caused by the tilt mechanism 220 can be converted into linear motion at the coupling mechanism 240 through the coupling of the tilt mechanism 220 and the coupling mechanism 240. Furthermore, the linear motion at the coupling mechanism 240 can be converted into torsional motion at the pitch mechanism 230 through the coupling of the pitch mechanism 230 and the coupling mechanism 240. As a result, the motion caused by the tilt mechanism 220 can be converted into torsional motion at the pitch mechanism 230 through the coupling mechanism 240. Thus, the actuator 221 of the tilt mechanism 220 can simultaneously actuate and / or control both the tilt mechanism 220 and the pitch mechanism 230 in a linked manner.

[0087] In some embodiments, coupling mechanism 240 may include one or more components directly coupled to pitch mechanism 230, such as Figures 2A to 2B. Additionally, coupling mechanism 240 can include one or more components that are indirectly coupled to tilt mechanism 220. For example, similar to tilt mechanism 220, coupling mechanism 240 can include one or more components that are coupled to support structure 106 and propulsion system 101. As a result, even if coupling mechanism 240 does not directly contact tilt mechanism 220, changes in the relative position and / or angle between support structure 106 and propulsion system 101 (e.g., as caused by tilt mechanism 220) can cause movement of one or more components of coupling mechanism 240. In other embodiments, coupling mechanism 240 can be directly coupled to one or more components of tilt mechanism 220. Tilt mechanism

[0088] More specifically, if Figures 2A to 2B As shown in FIG, in some embodiments, the tilt mechanism 220 may include an actuator 221, a load path including a rod 223, and a connection point 225. As examples, the actuator 221 may include a motor (e.g., an electric motor) or a hydraulic system. Embodiments allow the actuator 221 to include a local power source (e.g., a battery) and / or be connected to a separate aircraft power source (e.g., a battery). In addition, the actuator 221 may communicate with and be controlled by the aircraft's central control system.

[0089] The load path including rod 223 can be coupled to support structure 106 and propulsion system 101 at connection point 225. Connection point 225 can be a rotatable connection point, such as a ball screw, a pin, or any other suitable form of connection. Rod 223 can be extendable (e.g., a "slider" configured for telescopic movement) and can thereby provide an extendable or otherwise dynamic and adjustable connection between propulsion system 101 and support structure 106. As rod 223 extends and retracts, the tilt position of propulsion system 101 can change. Rod 223 can be coupled to actuator 221 and / or controllably extended and retracted by actuator 221. As a result, the tilt configuration of propulsion system 101 can be controlled by actuator 221 via rod 223. Actuator 221 and rod 223 can be collectively referred to as a linear actuator. Figures 2A to 2B The tilt mechanism 220 shown in FIG. 2 is for exemplary purposes, and embodiments allow for any other suitable tilt mechanism components and configurations. Pitch mechanism

[0090] The pitch mechanism 230 may include a transfer rod 231, a hub 232, one or more blade rods 233, and one or more rotatable base components 234. The transfer rod 231 (which may also be referred to as a slider) may be positioned along the centerline of the propulsion system 101. The transfer rod 231 may be coupled to a coupling mechanism 240 at one end and to a hub 232 (e.g., a central portion of the hub) at the other end. Movement of the coupling mechanism 240 (e.g., which may be caused by movement of the tilt mechanism 220) may cause the transfer rod 231 to move linearly forward and backward along the centerline of the propulsion system 101 (e.g., sliding piston movement), which in turn may cause similar linear movement of the hub 232. During the forward flight configuration 212, the centerline of the propulsion system 101 may be aligned with the x-axis (e.g., Figure 2B ) or close to the x-axis (e.g., angled up or down within a few degrees of the x-axis). During vertical flight configuration 211, the centerline of propulsion system 101 may be aligned with the z-axis (e.g., Figure 2A ) or near the z-axis (e.g., angled forward or rearward within a few degrees of the z-axis). The hub 232 (also known as a collective) can be coupled to one or more blade bars 233 (also known as pitch links and / or push rods), which can be positioned at or near points along the outer periphery of the hub 232. Movement of the hub 232 can result in similar forward and rearward movement of each of the one or more blade bars 233. Each of the blade bars 233 can be coupled to and / or combined with a corresponding rotatable base component 234, which can also be referred to as a blade cuff. The blade bars 233 and the corresponding rotatable base component 234 can be configured such that forward and rearward movement of the blade bars 233 can result in rotation of the rotatable base component 234. For example, rotatable base member 234 may be circular, and blade bar 233 may be coupled to an outer surface of the circular shape such that lateral movement of blade bar 233 may be converted into rotation at rotatable base member 234. A corresponding rotor blade 250 may be coupled to rotatable base member 234 such that rotation of rotatable base member 234 may cause rotor blade 250 to change pitch. Depending on the embodiment, each rotor blade 250 may be grouped with and coupled to a corresponding rotatable base member 234 and blade bar 233.

[0091] As shown, pitch mechanism 230 may be located entirely on propulsion system 101 and / or considered part of propulsion system 101. Additionally or alternatively, according to some embodiments, actuator 221 and any other suitable components of coupling mechanism 240 and tilt mechanism 220 may also be considered part of pitch mechanism 230, as they may participate in generating the pitch movement. Figures 2A to 2BThe pitch mechanism 230 shown in FIG. 2 is for exemplary purposes, and embodiments allow for any other suitable pitch mechanism components and configurations.

[0092] exist Figures 4A to 4D Another example of a pitch mechanism 230 is shown in isolation in FIG. FIG. Figure 4A mid) through the intermediate pitch position (e.g., between 4B and Figure 4C ) to a second pitch position (e.g., Figure 4D ), when the propulsion system 101 is in a vertical flight configuration (e.g., Figure 4A tilt or move to a forward flight configuration (e.g., Figure 4D Snapshot of the pitch mechanism 230 at (center). Figures 4A to 4D Each of includes a first cross-sectional image revealing components of pitch mechanism 230 within propulsion system 101 and a second image showing an exterior surface of propulsion system 101 with rotor blades 250. Figures 4A to 4D The progression illustrates how pitch mechanism 230 is actuated and, as a result, how rotor blades 250 rotate or twist through different pitch positions.

[0093] Another example of a pitch mechanism 930 is 9A to 9D is shown in near isolation (e.g., without the background of the propulsion system). 9A to 9D Pitch mechanism 930 in FIG. 1 is coupled to alternative coupling mechanism 906 , but the components of pitch mechanism 930 are otherwise similar. 9A to 9D The pitch mechanism 930 is shown in its position from a first pitch position (e.g., Figure 9A in) by the intermediate pitch position (e.g. Figures 9B to 9C ) and moves to a second pitch position (e.g., Figure 9D A snapshot of the time (in the middle). Described in more detail below 9A to 9D . Connecting mechanism

[0094] Return Reference Figures 2A to 2B , the coupling mechanism 240 may include any suitable components and structures for coupling the tilt mechanism 220 to the pitch mechanism 230. 5A to 5D, an example of a coupling mechanism 240 as shown by different snapshots of movement is illustrated in FIG. As shown, the coupling mechanism 240 may include a plurality of rigid structures 242, 244, and 247, which may include rods, bars, angle connectors, and / or any other structure suitable for translational motion. The first rigid structure 247 may be a pitch link, the second rigid structure 244 may be a rocker link, and the third rigid structure 242 may be a push rod link. In addition, the coupling mechanism 240 may include connection points 241, 243, 245, 246, and 248, which may take the form of pins or any other suitable rotational connection points. Connection point 248 may connect the coupling mechanism 240 to the support structure (e.g., a boom) of the aircraft. Connection point 241 may connect the coupling mechanism 240 to the transfer rod 231 of the pitch mechanism 230 on the propulsion system 101. The remaining connection points 243, 245, and 246 may connect the rigid structures 242, 244, and 247 and form one or more prismatic joints. The components can be sized and arranged so that when the propulsion system is tilted (e.g., as caused by actuator 221 of tilt mechanism 220), coupling mechanism 240 is set in relative motion (e.g., by changing the shape or position of the components), and so that this movement causes transfer rod 231 of pitch mechanism 230 to be set in motion. For example, the propulsion system 101 can tilt about a first pivot point (or center of rotation), and coupling mechanism 240 can have a second pivot point that is offset from the first pivot point. The offset between the two pivot points causes relative motion, and thereby causes movement of transfer rod 231.

[0095] 5A to 5D An example of the movement of coupling mechanism 240 is shown when propulsion system 101 tilts from a vertical flight configuration to a forward flight configuration (as caused by an actuator of tilt mechanism 220). Figure 5A Can represent vertical flight configuration, Figure 5D can represent a forward flight configuration, and Figures 5B to 5C Intermediate tilt angles and configurations may be represented. From the aircraft's reference frame, the propulsion system 101 tilts from vertical to horizontal, and the connection point 248 (and the aircraft and support structure, not shown) remains fixed. However, to illustrate the movement of the coupling mechanism 240, 5A to 5D, is in the reference frame of propulsion system 101. As a result, propulsion system 101 is depicted similarly and unchanged on the snapshot, and the movement of coupling mechanism 240 is easier to see. As shown, within this reference frame, the components of coupling mechanism 240 are displaced generally toward the left, rigid structure 247 is displaced downward and rotated from angled to approximately horizontal, and rigid structure 242 is displaced upward. As rigid structure 242 is displaced upward, transfer rod 231 of pitch mechanism 230 is also displaced upward, which in turn results in a change in pitch at the rotor blades. Thus, active tilting of propulsion system 101 can result in responsive (or passive) motion at coupling mechanism 240, and thereby also in responsive (or passive) motion at pitch mechanism 230. These movements can all be caused by and controlled by a single actuator, such as a Figure 2A The actuator 221 of the tilting mechanism 220 is shown in FIG. Nonlinear tilt-pitch relationship

[0096] Return Reference Figures 2A to 2B The coupling of tilt mechanism 220 to pitch mechanism 230 can be configured such that a change in the tilt angle can be translated into any suitable change in pitch position. In some embodiments, the change in the tilt angle can have a linear relationship with the responsive change in pitch. For example, a 1-degree change in the tilt angle can result in any suitable corresponding change in pitch (e.g., 0.1 degrees, 0.3 degrees, 0.5 degrees, 0.8 degrees, 1 degree, 2 degrees, etc.), regardless of the current pitch position and / or tilt angle.

[0097] In other embodiments, the change in tilt angle may have a non-linear relationship to the responsive change in pitch position.In addition to the amount of change in tilt angle, the amount of pitch change may also depend on the current tilt angle and / or pitch position.

[0098] The coupling between the tilt mechanism and the pitch mechanism may be configured to provide such a nonlinear relationship between the tilt angle and the pitch position. For example, according to an embodiment, the coupling mechanism 240 may be configured to provide a nonlinear relationship between the tilt angle and the pitch position. For example, referring back to 5A to 5D Any suitable non-linear relationship between the tilt angle and the pitch position may be achieved by corresponding configuration (e.g., shape, size, and / or location) of one or more of the rigid structures 242, 244, and / or 247 and / or one or more of the connection points 241, 243, 245, 246, and / or 248. The configuration of the rigid structures 242, 244, 247 and / or the connection points 241, 243, 245, 246, 248 may collectively influence the linear motion generated by the coupling mechanism 240 at the transfer rod 231 as the tilt angle changes, and may therefore be arranged such that certain blade pitch positions are achieved at corresponding predefined tilt angles as desired.

[0099] exist Figure 6 An example of a nonlinear relationship between tilt angle and pitch position is illustrated in graph 600 of FIG. In graph 600, the x-axis represents the tilt angle 620 of the propulsion system, where the tilt angle increases to the right. The y-axis represents the pitch position 630 of one or more rotor blades of the propulsion system, where the pitch position increases as the y-value increases.

[0100] Graph 600 includes a set of plotted points illustrating examples of pitch positions that may be linked to and / or result from corresponding tilt angles due to the configuration of the coupling between the tilt mechanism and the pitch mechanism. As shown, the pitch position generally increases as the tilt angle decreases.

[0101] Point 680 may represent a pitch angle associated with the vertical flight configuration (e.g., approximately 90 degrees), and a first pitch position used during the vertical flight configuration. The first pitch position may be any suitable pitch for vertical flight, such as a pitch position between approximately 5 degrees and approximately 25 degrees (e.g., 5 degrees, 10 degrees, 15 degrees, 18 degrees, 20 degrees, 23 degrees, 25 degrees).

[0102] Point 690 may represent a pitch angle associated with the forward flight configuration (e.g., approximately 0 degrees), and a second pitch position used during the forward flight configuration. The second pitch position may be any suitable pitch for forward cruise flight, such as a pitch position between approximately 30 degrees and approximately 50 degrees (e.g., 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees).

[0103] Graph 600 illustrates the nonlinear change in pitch position 630 as the pitch angle 620 is varied. It is noteworthy that at higher pitch angles (e.g., near point 680), the pitch position has a relatively small change (e.g., amount of change). At lower pitch angles (e.g., near point 690), the pitch position has a relatively large change (e.g., amount of change).

[0104] Compared to a linear relationship, this type of nonlinear relationship can advantageously allow lower pitch positions 630 to be used for a wider range of tilt angles 620. Lower pitch positions can provide greater thrust and, therefore, may be desirable for various flight phases that utilize intermediate tilt angles 620. For example, during forward acceleration and altitude gain, the propulsion system may tilt through a series of intermediate tilt angles to provide components of both forward acceleration and vertical lift. Greater thrust output may be desirable for these flight phases, so maintaining a lower pitch position may be beneficial even as the propulsion system continues to tilt.

[0105] Later, when the aircraft has increased in altitude and speed and is entering the forward cruise phase of flight, the propulsion system's tilt angle may approach a horizontal orientation. At this point, it may be advantageous to change the pitch position more quickly to a higher pitch position, as a higher pitch position may produce the desired efficiency during forward cruise flight.

[0106] 690 ).Chart 600 includes point 685, and its mark approaches the intermediate tilt angle of the horizontal (or approximately horizontal) angle of forward flight configuration.This intermediate tilt angle can be referred to as the 3rd tilt angle.The 3rd tilt angle at point 685 can be slightly higher than horizontal plane (for example, 3 degree, 5 degree, 8 degree, 10 degree, 15 degree or any other suitable angle).As shown, due to the steep curve in this area of ​​chart 600, the pitch position at point 685 (it can be referred to as the 3rd pitch position) is still lower meaningful amount than the second pitch position at point 690.The 3rd pitch position can be lower any suitable amount than the second pitch position, such as low 3 degree, low 5 degree, low 7 degree, low 10 degree, low 15 degree, low 20 degree etc.

[0107] In some embodiments, during the acceleration phase and the height increase phase of flight, the propulsion system can continuously or regularly tilt from the vertical flight configuration toward the forward flight configuration. However, the tilting can be suspended for any suitable amount of time at the third tilt angle of point 685. This allows the propulsion system to provide a main horizontal thrust (e.g., similar to the forward flight configuration) while also maintaining a third pitch position that is lower than the second pitch position, and thus providing a larger thrust output. Once sufficient speed and altitude are obtained, a final tilt from point 685 to point 690 can be performed to reach the forward cruise flight configuration. This final small tilt is not a large adjustment to the thrust direction, but the rotor blade pitch position can be functionally modified so that efficiency now takes precedence over the maximum thrust output for forward cruise flight.

[0108] In other words, the nonlinear relationship shown in graph 600 may effectively allow the pitch position to be controlled and modified in relative isolation when the current tilt angle approaches point 690, without requiring a significant change in the tilt angle, even though the tilt angle is coupled to the pitch position. Similarly, the nonlinear relationship shown in graph 600 may effectively allow the pitch angle to be controlled and modified in relative isolation when the current tilt angle approaches point 680, without requiring a significant change in the pitch position, even though the tilt angle is coupled to the pitch position. hydraulic lines

[0109] Embodiments provide various mechanisms integrated with the tilt mechanism of the tilt-lift fan for coordinating the tilt angle of the tilt-lift fan with the blade pitch angle of the rotor blades. Thus, embodiments reduce complexity and eliminate the need for additional actuators for pitch control.

[0110] In some embodiments, instead of coupling the pitch mechanism to the actuator through a coupling mechanism and / or a tilt mechanism (eg, in series), the pitch mechanism may be coupled directly to the actuator (eg, in parallel with the tilt mechanism).

[0111] For example, an exemplary mechanism may include a hydraulic system having a first line to a tilt mechanism and a second line to a pitch mechanism. The hydraulic system may include a master cylinder connected to the tilt mechanism and a slave cylinder connected to the pitch mechanism. A hydraulic line may couple the slave cylinder to a line connecting a pump to the first cylinder. When the pump moves the master cylinder, the hydraulic line from the master cylinder to the slave cylinder drives the slave cylinder. Thus, one pump drives two cylinders through a hydraulic linkage, thereby acting as a single actuator that drives both the tilt of the tiltable lift fan and the blade pitch of the tiltable lift fan's blades. Additional actuator for low pitch control

[0112] According to some embodiments, an additional actuator may be included for small controls of the pitch mechanism. The pitch mechanism may still be coupled to the tilt mechanism, but this second actuator may provide small adjustments to the total pitch position. For example, the second actuator may be able to adjust the pitch position by 0.5 degrees, 1 degree, 1.5 degrees, 2 degrees, 5 degrees, or any other suitable amount relative to the total pitch position resulting from the coupling to the tilt mechanism. The second actuator may be located entirely on the propulsion system, or some or all of the second actuator may be located on the support structure or elsewhere on the aircraft. Position Sensor

[0113] According to some embodiments, Figures 2A to 2B , position sensor 290 may be included as part of pitch mechanism 230 or otherwise included on propulsion system 101. Position sensor 290 may be positioned at and / or coupled to any suitable portion of pitch mechanism 230 and / or one or more rotor blades 250.

[0114] Position sensor 290 may be configured to monitor the current pitch position of one or more rotor blades. Position sensor 290 may also be configured to communicate with a control system and provide information about the current pitch position. Due to the coupling between tilt mechanism 220 and pitch mechanism 230, the control system may indirectly control pitch mechanism 230 (e.g., via tilt mechanism 220) and may not be able to determine via tilt mechanism 220 or actuator 221 whether pitch mechanism 230 is functioning according to predefined conditions or is positioned as intended. Thus, position sensor 290 may provide pitch position information that may otherwise be lost through the coupling arrangement. Offset pivot mechanism

[0115] According to various embodiments, an exemplary coupling mechanism may include a biased pivot mechanism. 7A to 7C An example of a propulsion system having a pitch mechanism coupled to a tilt mechanism via an offset pivot mechanism is shown in accordance with certain embodiments. According to various embodiments, offset pivot mechanism 750 is coupled to tiltable lift fan 701. Offset pivot mechanism 750 may include a first mechanism, a second mechanism, and a third mechanism.

[0116] The first mechanism may include a linear actuator 723 having a ball screw 727 coupled thereto. The first mechanism may enable the entire tiltable lift fan 701 to rotate in a manner such as Figure 7A The vertical flight configuration shown in FIG. Figure 7C Pivoting between the forward flight configurations shown in FIG.

[0117] The third mechanism may include a first element 738 (e.g., a connecting rod) and a second element 731 (e.g., a block) extending through the centerline of a motor (e.g., a motor of the tiltable lift fan 701). The third mechanism may convert the tilting motion into piston motion of the second element 731. Figure 7C In the forward flight configuration shown in , the second element 731 is pulled to the left out of the motor. Figure 7A In the vertical flight configuration shown in , the second element 731 is pushed to the right into the motor. The second element 731 has a linear motion in and out of the motor, which may not allow twisting.

[0118] The second mechanism converts the linear motion of the second element 731 into torsional motion of one or more rotor blades (e.g., via a torsional cuff coupled to the rotor blades). As a result, the pitch position of the rotor blades can be changed when the tiltable lift fan 701 pivots between different tilt configurations.

[0119] Depending on the embodiment, the first element 738 may have a second pivot point that is eccentric or otherwise not differently positioned relative to the first pivot axis of the tiltable lift fan 701. The different center of rotation results in linear movement (or a change in length) of the second element 731. The movement of the second element 731 results in a change in blade pitch.

[0120] According to various embodiments, one or more of the joints in the biased pivot mechanism 750 can be a rotational joint that provides surface contact between all moving elements. In some embodiments, the biased pivot mechanism 750 can include roller bearings or bushing-like surface contact on the joints.

[0121] According to various embodiments, offset pivot mechanism 750 may provide rotor blade pitch variation of approximately 40 to 70 degrees. Four-bar crank slider

[0122] According to various embodiments, an exemplary coupling mechanism may include a four-bar slider crank mechanism. Figures 8A to 8B Another example of a coupling mechanism according to various embodiments is shown in the form of an exemplary four-bar slider-crank mechanism 800. The four-bar slider-crank mechanism 800 includes a first bar 804, a second bar 810, a third bar 812, and a fourth bar 814. An inner bar 816 slides into and out of (e.g., telescopes) the fourth bar 814, forming a slider.

[0123] The four-bar slider crank 800 includes a first element 102 that slides linearly along a first rod 804, a second element 808 (e.g., a first joint) rigidly connected to a second rod 810, and a third element 806 (e.g., a second joint) connected between the second element 808 and the first element 802, thereby forming a four-bar slider crank. The second element 808 is a prismatic joint between the first element 802 and the first rod 804. The third element 806 is tethered to the second element 808 rather than to the ground.

[0124] According to various embodiments, a four-bar slider-crank mechanism 800 can be coupled to a tiltable lift fan. A first element 802 can be coupled to a pitch mechanism of the lift fan, which can change the pitch of the lift fan's rotor blades. A first rod 804 can be coupled to a motor of the lift fan, wherein a propeller is attached to the motor.

[0125] Figure 8A The system (eg, a four-bar slider-crank mechanism 800 coupled to a tiltable lift fan) is shown in a forward flight configuration. Figure 8B The system is shown in the vertical flight configuration.

[0126] In response to the lift fan tilting from the forward flight configuration to the vertical flight configuration, the first element 802 may slide upward, resulting in linear motion. The linear motion is then converted into rotational motion of the first rod 804 via the second element 808 and the third element 806. As the tiltable lift fan moves from the vertical flight configuration back to the forward flight configuration, the first element 802 slides relative to the first rod 804 because the axial sliding activates the blade pitch mechanism, thereby providing axial piston motion.

[0127] First element 802, second element 808, and third element 806 enable sliding movement of inner rod 816 into and out of fourth rod 814. Relative movement of first rod 804 and third rod 812 or second rod 810 actuates the blade pitch mechanism. Thus, depending on the embodiment, the blade pitch mechanism may not require an additional actuator dedicated to changing the blade pitch. Roller cam on centerline

[0128] Embodiments allow the coupling mechanism to take any other suitable form. As another example, the coupling mechanism may take the form of a roller cam coupled to a structure having a curved slot. The roller cam may be coupled to a transfer rod of the pitch mechanism, and the structure having the curved slot may be attached to a support structure (e.g., and not on the propulsion system). As a result, tilting of the propulsion system may cause the roller cam to roll within the curved slot. As the roller cam rolls, the curvature and / or tilting movement of the slot may cause the roller cam to press inward and / or pull outward relative to the pitch mechanism (e.g., depending on the direction of tilt), and thereby move the transfer rod of the pitch mechanism forward and backward.

[0129] 9A to 9D A centerline roller cam mechanism 900 is illustrated in accordance with various embodiments. The centerline roller cam mechanism 900 includes a static portion 906 (eg, a structure having a curved slot) and a pivoting portion 950 that may include a pitch mechanism 930 and a roller cam 904.

[0130] exist 9A to 9D In the embodiment, the static portion 906 (which may be a coupling mechanism, for example) corresponds to Figure 7A to the first element 738 illustrated in FIG. 7D , and the slider 931 corresponds to Figure 7A 7D . Pivoting portion 950 is coupled to static portion 906 and pivots relative to static portion 906 along a predetermined path 908. While one end of pivoting portion 950 is coupled to static portion 906, the opposite end includes a root sleeve 902 for each blade of the tiltable lift fan that can be coupled to roller cam mechanism 900 on the centerline.

[0131] When the pivoting portion 950 pivots relative to the static portion 906 (eg, due to pitching of the propulsion system), the shroud 902 coupled to the blade twists. 9A to 9D The illustration shows the twisting of the sleeve 902 in a left twisting motion as the pivoting portion 950 pivots in a counterclockwise motion relative to the static portion 906. The centerline roller cam mechanism 900 converts the tilt angle of the pivoting portion 950 into piston motion of the slider 931, which in turn changes the blade pitch by twisting the sleeve 902 coupled to the blade.

[0132] Pitch mechanism 930 converts the linear motion of slider 931 into torsional motion of the blade (e.g., by twisting a sleeve coupled to the blade). For example, pitch mechanism 930 may include a coupler 920 disposed around the distal end of slider 931. Coupler 920 may have a star shape as illustrated in FIG. Coupler 920 may move with slider 931 in linear motion.

[0133] The coupler 920 can be attached to a plurality of blades via an attachment device 922 (e.g., a cuff). For example, the coupler 920 can be coupled to the attachment device 922 via one or more links 924 extending parallel to the slider 931. Linear movement of the slider 931 and the coupler 920 causes the links 924 to move linearly, which then rotates the attachment device 922 and, thereby, the blades.

[0134] According to various embodiments, the geometry of the curved slot 908 of the static portion 906 can be modified (e.g., linear, parabolic, etc.) to change the blade pitch schedule. For example, a sharper curve in a first designated region along the curved slot 908 (e.g., corresponding to a first range of pitch angles) can produce faster pitch changes, while a sharper curve in a second designated region along the curved slot 908 (e.g., corresponding to a second range of pitch angles) can produce slower pitch changes. The curved slot 908 can be a sealed opening that is sealed to prevent foreign debris. control system

[0135] Re-reference Figure 1A to Figure 1B According to various embodiments, the aircraft 100 may be an electric aircraft or a hybrid electric aircraft. One or more battery cells may be included in the aircraft 100 (e.g., within the fuselage 104) and configured to provide power to various aircraft components (such as one or more electric motors and / or onboard computer systems). The propulsion systems 101(A)-(L) may be driven by electric motors that are powered by an electric power system including one or more battery cells. In some embodiments, each of the propulsion systems 101(A)-(L) may be coupled to a dedicated battery cell. Alternatively, there may be a one-to-many relationship between the one or more battery cells and the propulsion systems 101(A)-(L). In some cases, the one or more battery cells may be the sole power source for the aircraft 100. Each battery cell may include one or more battery cells.

[0136] According to various embodiments, the aircraft 100 may include a control system 107, such as a flight control system, configured to control the aircraft 100. The control system 107 may be configurable to control the aircraft 100 automatically and / or remotely (e.g., via control signals received from a remote entity such as a remote controller, a remote pilot, or a remote control tower). In various embodiments, the control system 107 may include a controller having Storage Index One or more computers containing one or more non-transitory computer-readable media containing instructions, and one or more processors configured to execute the instructions so as to perform the processing and control functions described herein.

[0137] For example, the control system 107 may control when the propulsion systems 101(A)-(L) should be operated and / or the amount of power provided to the propulsion systems 101(A)-(L). The control system 107 may be configurable to control the propulsion systems 101(A)-(L) independently of each other. According to various embodiments, the control system 107 may control the propulsion systems 101(A)-(L) based on input received from a remote controller (e.g., a remote pilot), input received from an autopilot, sensor data received from sensors (e.g., sensors measuring air temperature, electric motor temperature, aircraft airspeed, etc.), computers, and other input / output devices coupled to the aircraft, and / or flight data.

[0138] The flight control system 107 may also control one or more tilt mechanisms to switch the positioning of the one or more tilt fans from a forward flight configuration to a vertical flight configuration, from a vertical flight configuration to a forward flight configuration, to one or more intermediate tilt angles, and / or sweep through a range of tilt angles, according to the flight plan or as needed. According to various embodiments, a control system (e.g., a flight control system) may control the angles of the tilt fans based on sensor data and / or flight data received from sensors (e.g., sensors measuring air temperature, electric motor temperature, aircraft airspeed, etc.), computers, and other input / output devices coupled to the aircraft.

[0139] The flight control system 107 can also control one or more pitch mechanisms to switch the positioning of one or more rotor blades between two or more pitch positions. According to various embodiments, the flight control system 107 can control the rotor blade pitch position based on sensor data and / or flight data received from sensors (e.g., sensors measuring air temperature, electric motor temperature, the airspeed of the aircraft, etc.), computers, and other input / output devices connected to the aircraft. The pitch of the rotor blades can be set based on the current flight phase and / or flight demand. For example, during the time when the aircraft is accelerating (e.g., forward or upward), hovering, taking off and / or landing, a first pitch that can be a low pitch can be selected. When the aircraft has reached cruising flight (e.g., has reached a predefined forward speed), a second pitch that can be a high pitch can be selected.

[0140] As discussed above, in some embodiments, the pitch mechanism may be coupled to the tilt mechanism. In this case, the flight control system 107 may also use one or more shared actuators and control the tilt mechanism and the pitch mechanism together according to a predefined relationship between the tilt angle and the pitch position. The flight control system 107 may determine and adjust the tilt angle of the tilt fan and the pitch position of the rotor blades based on the current flight phase and / or flight requirements. The flight control system 107 may prioritize the tilt angle by selecting the most appropriate tilt angle and allowing the pitch mechanism to be passively adjusted. The relationship between the tilt angle and the pitch position may be preconfigured so that the corresponding pitch position will typically or always be appropriate for a given tilt angle. In some embodiments, the flight control system 107 may prioritize the pitch position when the tilt angle is close to horizontal. For example, the flight control system 107 may be configured to select a third tilt angle slightly above horizontal to allow a lower pitch position (e.g., the second pitch position as discussed above) than the predefined pitch position paired with the horizontal tilt angle (e.g., the third pitch position as discussed above).

[0141] Thus, the control system 107 may be configured to convert pilot or other operator inputs and / or corrections calculated by the onboard computer into forces and moments, and / or further convert such forces and moments into sets of actuators (e.g., vertical lift rotors; propellers; control surfaces, such as ailerons; etc.) and / or associated parameters (e.g., lift fan power, tilt angle, rotor blade pitch, speed, or torque) to provide the desired forces and moments. For example, the pilot or other operator input may indicate a desired change in the speed, direction, and / or orientation of the aircraft, and / or wind or other forces may be acting on the aircraft, requiring the use of the propulsion system and / or other actuators to maintain a desired aircraft attitude (roll / pitch / yaw), speed, and / or altitude.

[0142] According to various embodiments, the control system 107 may be configurable to receive a flight instruction, such as a takeoff, hover, cruise, or landing instruction. The control system 107 may then determine the current position and / or speed of the aircraft 100 and then control the operation of the propulsion systems 101 (A)-(L) based on the flight instruction. During operation of the aircraft 100, the control system 107 may be configurable to continuously monitor the operating status of the propulsion systems 101 (A)-(L) according to the flight instruction.

[0143] Aircraft 100 may also include landing gear 130. Landing gear 130 may include any suitable combination of one or more skids, wheels, slides, floats, shock absorbers, struts, and / or any other suitable components for supporting aircraft 100 during landing and / or landing on the ground. In some embodiments, landing gear 130 may be retractable into a compartment within fuselage 104.

[0144] Aircraft 100 may include any other suitable control structures and control surfaces. Any suitable number of ailerons, rudders, elevators, slats, flaps, spoilers, and / or stabilizers may be included. For example, a horizontal stabilizer 140 (e.g., a tailplane) may be coupled to the rear end or tail of fuselage 104. Horizontal stabilizer 140 may be of any suitable shape or form. For example, Figure 1A to Figure 1B As shown in , the horizontal stabilizer 140 may include two stabilizer surfaces projecting horizontally from the tail. In some embodiments, each of the stabilizer surfaces may also include an articulation control surface on the rear edge. In addition, as shown in Figure 1A to Figure 1B As shown in FIG, additional (e.g., third) vertical stabilizer surfaces may be mounted on the tail, extending vertically upward and / or downward. Introducing the horizontal stabilizer 140 may provide additional stability and control of the aircraft 100. This may be particularly useful when the vertical fans are disabled or otherwise not utilized or relied upon for control and stability (e.g., during cruise flight). Flight process

[0145] According to various embodiments, a control system may control flight of an aircraft configured for vertical takeoff and landing.

[0146] The aircraft may be in a stationary position on the ground. For example, the aircraft may be parked at a charging station for charging batteries. Alternatively, the aircraft may be parked in a location awaiting the receipt of cargo or passengers. The aircraft's flight control system may receive a flight plan (e.g., from an autopilot, a pilot, or a remote control pilot) to reach a predetermined destination. The flight plan may include instructions for takeoff from the ground. The flight control system may control one or more of the propulsion systems to activate. For example, the aircraft's thrust-generating components may be deactivated or placed in a standby mode. The flight control system may power the propulsion systems from the deactivated mode so that they are ready to generate vertical lift.

[0147] The control system is operably coupled to a first set of one or more propulsion systems of the aircraft. Each of the first set of one or more propulsion systems may have two or more rotor blades and a fixed vertical orientation or a tiltable orientation currently set in a vertical flight configuration.

[0148] For example, the flight control system may initiate a takeoff sequence to lift the aircraft off the ground. The flight control system may operate the first set of one or more propulsion systems to provide vertical thrust to lift the aircraft off the ground. The flight control system may continue to operate the first set of one or more propulsion systems in this manner until a certain time has passed or a certain altitude has been reached (e.g., a safe distance from a landing pad). The control system may continue to operate the first set of one or more propulsion systems to provide vertical thrust during liftoff, hovering, landing, or any other suitable phase of flight.

[0149] The control system may at certain times control one or more of the first set of one or more propulsion systems (such as fixed vertical fans) to cease operation during other flight phases (such as forward cruise flight), when vertical lift may be provided additionally and / or alternatively by the aircraft's wings. For example, after a certain amount of time has passed and / or after increasing altitude, the flight control system may receive a command to transition to forward flight. Before switching to forward flight mode, the control system may check one or more of the aircraft's altitude, speed, and orientation to ensure that the parameters are within predetermined desired ranges. In some embodiments, the control system may transmit the parameters to a remote entity (e.g., a remote control tower or a remote pilot).

[0150] The control system can operate a second set of one or more propulsion systems. Each of the second set of one or more propulsion systems can have a fixed horizontal orientation or a tiltable orientation configured for forward flight. Each of the second set of one or more propulsion systems can have two or more rotor blades. In some embodiments, one or more propulsion systems (such as tilt fans) can be included in both the first set of one or more propulsion systems and the second set of one or more propulsion systems.

[0151] For example, upon receiving a flight command to transition to forward flight, the control system may operate the second set of one or more propulsion systems to generate forward thrust for the aircraft. The flight control system may control forward acceleration in any suitable manner, such as by gradually increasing power supplied to the second set of one or more propulsion systems so that the aircraft gradually acquires forward speed.

[0152] In some embodiments, the second set of one or more propulsion systems can be activated and begin providing forward thrust while the aircraft is still in the process of gaining altitude from the vertical lift fans. As a result, forward travel can overlap with vertical lift. Additionally, the flight control system can adjust the power of the first set of one or more propulsion systems as needed to maintain stability and altitude while the second set of one or more propulsion systems causes the forward airspeed to increase.

[0153] In some embodiments, one or more of the first set of propulsion systems and / or the second set of one or more propulsion systems can be operated to tilt between a forward flight configuration and a vertical flight configuration. Such tilting propulsion systems can be operated during both the one or more steps of providing vertical thrust and the one or more steps of providing horizontal thrust.

[0154] In some embodiments, one or more tilt propulsion systems may be operated to gradually, iteratively and / or continuously tilt from a vertical flight configuration to a forward flight configuration. When the tilt propulsion system is set to one or more intermediate tilt angles, thrust can be provided at an angle having a partial vertical component and a partial horizontal component. As the tilt propulsion system tilts through one or more intermediate tilt angles, the horizontal thrust component increases and the vertical thrust component decreases. In some embodiments, the one or more tilt propulsion systems may be operated to pause movement and tilting at a predefined intermediate tilt angle (referred to as a third tilt angle, a critical tilt angle, or a threshold tilt angle) that may be close to horizontal but above horizontal, while continuing to operate the propulsion system to provide thrust. Once a predefined speed and / or altitude is achieved, the one or more tilt propulsion systems may be operated to resume the tilting process until the forward flight configuration is reached.

[0155] The control system may set and / or modify the pitch position setting of one or more rotor blades of one or more propulsion systems (e.g., from the first group and / or the second group). In some embodiments, one or more rotor blades may be initially set to a first pitch position. The first pitch position may be maintained during one or more flight phases (such as takeoff and / or forward acceleration). The control system may later adjust the one or more rotor blades to have a second pitch position. For example, once cruising flight is reached (e.g., after reaching a certain forward speed), the pitch setting may be changed to the second pitch position. In some embodiments, the pitch setting may be gradually and / or iteratively changed from the first pitch position to the second pitch position as the forward speed increases, and may be gradually changed from the second position to the first position as the forward speed decreases.

[0156] In some embodiments, a pitch mechanism for one or more rotor blades of a tilt propulsion system may be coupled to a tilt mechanism of the propulsion system. As the tilt angle changes (e.g., decreases), the pitch mechanism is configured to automatically change (e.g., increase) in response. In some embodiments, the control system may operate the propulsion system to pause the tilt movement at a predefined intermediate tilt angle (referred to as a third tilt angle) that may be close to horizontal but above horizontal, such that a certain predefined pitch position (referred to as the third pitch position) coupled to the third tilt angle may be maintained while the aircraft continues to increase speed and / or altitude. Once a predefined speed and / or predefined altitude is achieved, the one or more tilt propulsion systems may be operated to resume the tilting process until a forward flight configuration is reached such that the pitch position may be changed accordingly to a predefined pitch position (referred to as the second pitch position) coupled to the forward flight pitch configuration.

[0157] The control system may continue to operate the second set of one or more propulsion systems to provide horizontal thrust during forward cruise flight, forward acceleration, deceleration, or any other suitable flight phase. The control system may at certain times control the first set of one or more propulsion systems to cease operation during other flight phases, such as liftoff, hovering, and / or landing. At certain points in time, the control system may simultaneously operate both the first set of one or more propulsion systems and the second set of one or more propulsion systems.

[0158] Subsequently, the flight control system may deactivate one or more of the first set of one or more propulsion systems, or otherwise reduce the power provided to the first set of one or more propulsion systems. For example, once the second set of one or more propulsion systems has generated a predetermined speed such that the wing provides sufficient lift to maintain altitude, the first set of one or more propulsion systems may no longer be needed for vertical lift. Thus, during forward flight of the aircraft, one or more of the first set of one or more propulsion systems may be powered off, deactivated, placed in standby mode, or operated at a reduced power level.

[0159] The control system may continue to alternate between operating one or more of the first group of one or more propulsion systems and / or the second group of one or more propulsion systems, continue to tilt one or more tilt propulsion systems, and / or continue to adjust the pitch position of one or more rotor blades (e.g., by adjusting the coupled tilt angle of the propulsion system).

[0160] In the foregoing description, embodiments of the present disclosure have been described with reference to many specific details, which may vary depending on the implementation. Therefore, the description and drawings are to be considered illustrative rather than restrictive. The sole and exclusive indicator of the scope of the present disclosure, and the scope of the present disclosure as intended by the applicant, is the literal and equivalent scope of the set of claims issued from this application, in the specific form in which such claims are issued, including any subsequent amendments. The specific details of a particular embodiment may be combined in any suitable manner without departing from the spirit and scope of the embodiments of the present disclosure.

[0161] In addition, spatially relative terms such as "bottom" or "top" may be used to describe the relationship of an element and / or feature to another element(s) and / or feature(s), for example, as illustrated in the accompanying drawings. It will be understood that the spatially relative terms are intended to include different orientations of the device in use and / or operation in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as a "bottom" surface may be oriented "above" other elements or features. The device may be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein are interpreted accordingly.

[0162] The methods, systems, and devices discussed herein are examples. Various embodiments may appropriately omit, substitute, or add various procedures or components. For example, features described with respect to certain embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be combined in a similar manner. In addition, technology is evolving, and therefore, many elements are examples that do not limit the scope of this disclosure to those specific examples.

[0163] As used herein, the terms "and", "or" and "and / or" may include a variety of meanings, which are also expected to depend at least in part on the context in which such terms are used. Typically, if used in association with a list such as A, B, or C, "or" is intended to mean A, B, and C (used here in an inclusive sense) as well as A, B, or C (used here in an exclusive sense). In addition, as used herein, the term "one or more" may be used to describe any feature, structure, or characteristic in the singular, or may be used to describe some combination of features, structures, or characteristics. However, it should be noted that this is merely an illustrative example, and the claimed subject matter is not limited to this example. In addition, if used in association with a list such as A, B, or C, the term "at least one of..." may be interpreted to mean any combination of A, B, and / or C, such as A, B, C, AB, AC, BC, AA, AAB, ABC, AABBCCC, etc.

[0164] References throughout this specification to "one example," "an example," "some examples," or "example embodiments" mean that a particular feature, structure, or characteristic described in connection with a feature and / or example may be included in at least one feature and / or example of the claimed subject matter. Thus, the appearances of the phrases "in one example," "an example," "in some examples," "in some embodiments," or other similar phrases in various places throughout this specification are not necessarily all referring to the same feature, example, and / or limitation. Furthermore, particular features, structures, or characteristics may be combined in one or more examples and / or features.

[0165] In the foregoing detailed description, numerous specific details have been set forth in order to provide a thorough understanding of the claimed subject matter. However, those skilled in the art will appreciate that the claimed subject matter may be practiced without these specific details. In other instances, methods and apparatus known to those of ordinary skill in the art have not been described in detail so as not to obscure the claimed subject matter. Therefore, it is intended that the claimed subject matter is not limited to the specific examples disclosed, but that such claimed subject matter may also include all aspects falling within the scope of the appended claims and their equivalents.

Claims

1. A system comprising: a tiltable propulsion system configured to move between a first tilt angle and a second tilt angle, wherein the tiltable propulsion system comprises a plurality of rotor blades, each of the plurality of rotor blades configured to move between a first pitch position and a second pitch position; a tilt mechanism coupled to the tiltable propulsion system and configured to move the tiltable propulsion system between the first tilt angle and the second tilt angle; a pitch mechanism coupled to one or more of the plurality of rotor blades and configured to move one or more of the plurality of rotor blades between the first pitch position and the second pitch position; and An actuator is configured to simultaneously operate the tilt mechanism and the pitch mechanism.

2. The system according to claim 1, further comprising: The coupling between the pitch mechanism and the tilt mechanism is such that movement of the tiltable propulsion system by the tilt mechanism results in corresponding movement of one or more of the plurality of rotor blades by the pitch mechanism.

3. The system according to claim 2, wherein: The coupling between the pitch mechanism and the tilt mechanism is configured such that each tilt angle of the tiltable propulsion system results in a pitch position of one or more of the plurality of rotor blades.

4. The system according to claim 3, wherein: The first tilt angle results in the first pitch position, and the second tilt angle results in the second pitch position.

5. The system according to claim 1, wherein: As the tilt mechanism moves the tiltable propulsion system between the first tilt angle and the second tilt angle, the pitch mechanism moves one or more of the plurality of rotor blades between the first pitch position and the second pitch position.

6. The system according to claim 2, wherein: The coupling between the pitch mechanism and the tilt mechanism is configured to provide a non-linear relationship between a tilt angle of the tiltable propulsion system and a pitch position of one or more of the plurality of rotor blades.

7. The system according to claim 6, wherein: When the tiltable propulsion system is set to the first tilt angle, the nonlinear relationship causes a first change in the pitch position of one or more of the plurality of rotor blades in response to a change in the tilt angle, and wherein, when the tiltable propulsion system is set to the second tilt angle, the nonlinear relationship causes a second change in the pitch position of one or more of the plurality of rotor blades in response to a change in the tilt angle, wherein the second change is greater than the first change.

8. The system of claim 1 , further comprising: A coupling mechanism coupling the pitch mechanism and the tilt mechanism, wherein the coupling mechanism is configured to convert a tilting motion caused by the tilt mechanism into a linear motion at the pitch mechanism, and wherein the pitch mechanism is configured to convert the linear motion into a rotational motion at one or more of the plurality of rotor blades.

9. The system according to claim 8, further comprising: A support structure is provided to which the tiltable propulsion system is coupled, wherein the coupling mechanism is connected to the support structure and the tiltable propulsion system.

10. The system according to claim 9, wherein: The coupling mechanism is indirectly connected to the tilting mechanism.

11. The system according to claim 8, wherein The coupling mechanism includes a first pivot point offset from a second pivot point of the tilt mechanism.

12. The system according to claim 8, wherein: The coupling mechanism includes a four-bar crank slider, and the pitch mechanism includes a slider coupled to the four-bar crank slider.

13. The system of claim 1, wherein: The actuator is a component of the tilt mechanism, and wherein the pitch mechanism is coupled to the tilt mechanism, the pitch mechanism operates without a separate dedicated actuator, the first tilt angle corresponds to a vertical flight configuration, and the second tilt angle corresponds to a forward flight configuration.

14. The system of claim 1 , further comprising: An aircraft, the aircraft comprising: body; a pair of wings coupled to opposite sides of the fuselage; one or more booms coupled to each of the pair of wings; and The tiltable propulsion system, wherein the tiltable propulsion system is coupled to a first boom of the one or more booms.

15. The system of claim 14, further comprising: A control system configured to simultaneously control the tilt mechanism and the pitch mechanism through the actuator, and configured to: operating the tilt mechanism to gradually move the tiltable propulsion system from the first tilt angle through a set of intermediate tilt angles to a third tilt angle; operating the tilt mechanism to pause movement of the tiltable propulsion system upon reaching the third tilt angle; and After the aircraft reaches a predetermined speed or a predetermined altitude, the tilt mechanism is operated to move the tiltable propulsion system from the third tilt angle to the second tilt angle.

16. The system according to claim 15, wherein: The first tilt angle corresponds to a vertical flight configuration, the second tilt angle corresponds to a forward flight configuration, and the third tilt angle is within 10 degrees of the second tilt angle.

17. The system of claim 15, further comprising: The connection between the pitch mechanism and the tilt mechanism is configured such that each tilt angle of the tiltable propulsion system results in a corresponding pitch position of one or more of the plurality of rotor blades, wherein the first tilt angle results in the first pitch position, the second tilt angle results in the second pitch position, and the third tilt angle results in a third pitch position, wherein the third pitch position is at least 3 degrees less than the second pitch position.

18. The system according to claim 17, wherein: The control system is further configured to: The pitch mechanism is operated to move one or more of the plurality of rotor blades from the third pitch position to the second pitch position.

19. The system according to claim 18, wherein: Operating the pitch mechanism to move one or more of the plurality of rotor blades from the third pitch position to the second pitch position is indirectly performed by operating the tilt mechanism to move the tiltable propulsion system from the third tilt angle to the second tilt angle.

20. The system of claim 1, wherein: The first pitch position corresponds to an acceleration pitch, and the second pitch position corresponds to an efficiency pitch.

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