Rotary airfoil with spring damper system

Abstract

An airfoil structure includes an airfoil and a spring and damper system. The airfoil includes a longitudinal axis. The spring and damper system is connected to the airfoil to rotate the airfoil about the longitudinal axis to change an airfoil pitch angle in response to a load applied to the airfoil.

Description

Technical Field

[0001] This disclosure relates to a rotating airfoil assembly, and more specifically, to a rotating airfoil assembly, such as a fan or propeller, for an engine that generates thrust for an aircraft. Background Technology

[0002] The thrust used to move an aircraft in the air can be generated by multiple airfoil elements rotating around a central axis. For example, multiple airfoil elements such as fan blades for a fan in an unducted single-fan engine or a propeller driving a propeller on an aircraft. As the fan or propeller rotates, some blades travel in the downward direction, and others travel in the upward direction. Attached Figure Description

[0003] The features and advantages of this disclosure will become apparent from the following description of various exemplary embodiments as shown in the accompanying drawings, wherein similar reference numerals generally indicate the same, functionally similar and / or structurally similar elements.

[0004] Figure 1 This is a schematic perspective view of an aircraft having a ductless single-fan engine with a rotating airfoil according to an embodiment of the present disclosure.

[0005] Figure 2 yes Figure 1 One of the ductless single-fan engines of the aircraft shown is along Figure 1 The schematic cross-sectional view is taken from line 2-2 in the figure.

[0006] Figure 3 yes Figure 1 One of the ductless single-fan engines of the aircraft shown is along Figure 1 Another schematic cross-sectional view taken from line 2-2 shows the engine mounting system used to mount the engine to the wing of the aircraft.

[0007] Figure 4 yes Figure 3 A detailed cross-sectional view of the front mount of the engine mounting system shown in the figure illustrates... Figure 3 Detail 4 in the text.

[0008] Figure 5 yes Figure 3 A detailed cross-sectional view of the rear mount of the engine mounting system shown in the figure illustrates... Figure 3 Detail 5 in the text.

[0009] Figure 6 yes Figure 1 The image shows a view of the aircraft during horizontal flight.

[0010] Figure 7This refers to the operational status used when the aircraft pitches up. Figure 1 The view of the aircraft shown.

[0011] Figure 8 yes Figure 1 The front view of the fan (rotating airfoil assembly) of one of the ductless single-fan engines of the aircraft shown.

[0012] Figure 9 This describes the operational state of an aircraft when it pitches upward and the airfoil assembly rotates, according to embodiments of this disclosure. Figure 1 The view of the aircraft shown.

[0013] Figure 10 This is a top view of an engine support structure according to an embodiment of the present disclosure.

[0014] Figure 11 yes Figure 1 One of the ductless single-fan engines of the aircraft shown is along Figure 1 The schematic cross-sectional view taken from line 2-2 shows the folded-up position. Figure 10 Engine support structure.

[0015] Figure 12 yes Figure 1 One of the ductless single-fan engines of the aircraft shown is along Figure 1 The schematic cross-sectional view taken by line 2-2 shows the unfolded position. Figure 10 Engine support structure.

[0016] Figure 13 This is a side view of an engine support structure according to an embodiment of the present disclosure.

[0017] Figure 14 yes Figure 13 The top view of the engine support structure shown.

[0018] Figure 15 This is a side view of an engine support structure according to an embodiment of the present disclosure.

[0019] Figure 16 It is along Figure 15 The line 16-16 in the middle is cut off Figure 15 The image shows a cross-sectional view of the rear mounting component of the engine support structure.

[0020] Figure 17 It is along Figure 16 The line 17-17 in the middle is cut off Figure 15 The image shows a cross-sectional view of the rear mounting component of the engine support structure.

[0021] Figure 18 This is a side view of an engine support structure according to an embodiment of the present disclosure.

[0022] Figure 19 This is a side view of an engine support structure according to an embodiment of the present disclosure.

[0023] Figure 20 This is a schematic cross-sectional view of a ductless single-fan engine according to an embodiment of the present disclosure. The cross-sectional view is from... Figure 1 The line 2-2 is cut from a perspective view similar to the one in the middle.

[0024] Figure 21 Shown in Figure 20 The differential gearbox used in the engine shown.

[0025] Figure 22 This is a schematic cross-sectional view of a ductless single-fan engine according to an embodiment of the present disclosure. The cross-sectional view is from... Figure 1 The line 2-2 is cut from a perspective view similar to the one in the middle.

[0026] Figure 23 This is a detailed cross-sectional view of the spherical bearing that supports the fan shaft.

[0027] Figure 24 This is a detailed cross-sectional view of the spherical bearing supporting the fan shaft, in which the fan shaft pivots.

[0028] Figure 25 This is a schematic cross-sectional view of a ductless single-fan engine during level flight according to an embodiment of the present disclosure. The cross-sectional view is from... Figure 1 The line 2-2 is cut from a perspective view similar to the one in the middle.

[0029] Figure 26 yes Figure 25 The ductless single-fan engine shown in Figure 9 A schematic cross-sectional view during the state shown.

[0030] Figure 27 This is a detailed cross-sectional view of the fan hub according to another embodiment.

[0031] Figure 28 It is along Figure 27 The cross-sectional view of the root of the fan blade is taken from line 28-28.

[0032] Figure 29 This is a cross-sectional view of the root of a fan blade according to another embodiment.

[0033] Figure 30 This is while the fan blades are rotating. Figure 29The image shows a cross-sectional view of the root of the fan blade.

[0034] Figure 31 It is shown that it is used for Figure 30 A diagram showing the effect of the spring damping system for the fan blades. Detailed Implementation

[0035] The features, advantages, and embodiments of this disclosure are set forth or become apparent from the following detailed description, drawings, and claims. Furthermore, the following detailed description is exemplary and intended to provide further explanation, without limiting the scope of the claimed disclosure.

[0036] Various embodiments are discussed in detail below. Although specific embodiments are discussed, they are for illustrative purposes only. Those skilled in the art will recognize that other components and constructions can be used without departing from the spirit and scope of this disclosure.

[0037] The terms "front" and "rear" refer to relative positions within a gas turbine engine or vehicle, and specifically to the normal operating posture of the gas turbine engine or vehicle. For example, in the context of a gas turbine engine, "front" refers to the position closer to the engine inlet, and "rear" refers to the position closer to the engine nozzle or exhaust port.

[0038] The terms "upstream" and "downstream" refer to the relative directions of fluid flow within a fluid path. For example, "upstream" refers to the direction from which the fluid flows, and "downstream" refers to the direction from which the fluid flows.

[0039] The terms “connection,” “fixation,” “attachment,” “linkage,” etc., refer to both direct connection, fixation, attachment, or linking, and indirect connection, fixation, attachment, or linking through one or more intermediate components or features, unless otherwise specified herein.

[0040] The singular forms “a,” “a,” and “the” include plural references unless the context clearly indicates otherwise.

[0041] As described above, the thrust used to move an aircraft in the air can be generated by multiple airfoils rotating about a central axis. For example, multiple airfoils such as fan blades for a fan in a ductless single-fan engine or propellers driving a propeller on an aircraft, with some blades traveling downwards and others upwards. When the aircraft is flying horizontally, air flows into the fan or propeller in the axial direction, and the downward-traveling blades and the upward-traveling blades produce equal amounts of thrust. However, when the aircraft has an angle of attack, air flows into the fan or propeller with a non-axial component, and the downward-traveling blades and the upward-traveling blades produce different amounts of thrust. For example, when the aircraft pitches upwards, such as during takeoff, the downward-traveling blades produce a greater amount of thrust than the upward-traveling blades, resulting in asymmetrical loading of the fan blades or propeller. Therefore, in one rotation, the rotating airfoil (fan blade or propeller) experiences differential loads (1P loads), resulting in a cyclic loading state of the rotating airfoil. In addition, these cyclic loads subject the rotating airfoil to fatigue stress and strain.

[0042] Rotating airfoils, such as fan blades for a turbofan engine or propellers driving an aircraft, may experience differential loads (1P loads) during rotation when the axis of rotation of the rotating airfoil is angled (e.g., pitching up or down) relative to the airflow entering the fan or propeller. In other words, this 1P load may occur when the airflow entering the propeller is not perpendicular to the plane of rotation of the rotating airfoil. The embodiments discussed herein reduce the magnitude of the asymmetric loads generated by the rotating airfoil, or even eliminate the asymmetric loads. In some embodiments discussed herein, the axis of rotation of the rotating airfoil assembly is aligned with the airflow entering the rotating airfoil assembly, or at least the angle of attack is reduced when the aircraft has an angle of attack. In some embodiments discussed herein, when the aircraft has an angle of attack aligned with the engine, the entire engine rotates, thus aligning the rotating airfoil assembly with the airflow entering the rotating airfoil assembly; however, in other embodiments, the rotating airfoil assembly rotates while other parts of the engine remain fixed relative to their orientation to the aircraft. In other embodiments, the rotating airfoils themselves can change their orientation as they rotate about an axis of rotation, thereby altering the plane of rotation of the airfoils. In some embodiments discussed herein, the rotating airfoils are actively rotated by a controller and actuators. In further embodiments, the angle of the rotating airfoils (blades) can be changed to reduce asymmetric loads on the rotating airfoil assembly, and in the embodiments discussed below, this rotation is passively driven by a pressure differential on the rotating airfoils.

[0043] The rotating airfoil discussed in this article is suitable for use with rotating airfoil assemblies used to generate thrust for fixed-wing aircraft, particularly for open rotor engines such as propeller or ductless fan engines. Figure 1 This is a perspective view of an aircraft 10 that can be implemented in various preferred embodiments. The aircraft 10 includes a fuselage 12, a pair of wings 14 attached to the fuselage 12, and a tail 16. The fuselage 12 includes a nose 22 and a tail 24, with a centerline 26 extending from the nose 22 to the tail 24. In this embodiment, the centerline 26 of the fuselage 12 is also the centerline 26 of the aircraft 10. The aircraft 10 also includes a propulsion system that generates the thrust required to propel the aircraft 10 during flight, during taxiing operations, etc. Figure 1 The propulsion system of the aircraft 10 shown includes a pair of engines 100. In this embodiment, each engine 100 is attached to one of the wings 14 in an underwing configuration via a pylon 18. Although the engines 100 are in Figure 1 The engine 100 is shown attached to the wing 14 in an underwing configuration, but in other embodiments, the engine 100 may have an alternative configuration and be coupled to other parts of the aircraft 10. For example, the engine 100 may additionally or alternatively include one or more aspects coupled to other parts of the aircraft 10 (e.g., such as the tail 16 and fuselage 12).

[0044] Please refer to the following: Figure 2 Further description, Figure 1 The engine 100 shown is a ductless single-fan engine, each capable of selectively generating propulsive thrust for the aircraft 10. This thrust can be at least partially based via fuel system 130 (see fuel system 130). Figure 2 A certain amount of fuel is supplied to the ductless single-fan engine to control the amount of propulsive thrust. In the embodiments discussed herein, the aviation turbine fuel is a combustible hydrocarbon liquid fuel with the desired carbon number, such as kerosene-based fuel. The fuel is stored in fuel tank 131 of fuel system 130. Figure 1 As shown, at least a portion of the fuel tank 131 is located in each wing 14, and a portion of the fuel tank 131 is located in the fuselage 12 between the wings 14. However, the fuel tank 131 may be located in other suitable locations within the fuselage 12 or the wings 14. The fuel tank 131 may also be entirely located within the fuselage 12 or the wings 14. The fuel tank 131 may also be separate tanks instead of a single unit, such as two tanks each located within the respective wing 14.

[0045] Figure 2 Is Figure 1 A schematic cross-sectional view of one of the engines 100 used in the propulsion system of the aircraft 10 shown. Figure 2 Cross-sectional view along Figure 1Line 2-2 in the diagram is cut off. As described above, engine 100 is a ductless single-fan engine. The ductless single-fan engine 100 has an axial direction A (parallel to...) Figure 2 The longitudinal centerline 101 shown for reference extends in the center, along with the radial direction R and the circumferential direction. The circumferential direction ( Figure 2 (Not depicted) extends in a direction of rotation about the longitudinal centerline 101. The ductless single-fan engine 100 includes a fan section 102 and a turbine 104 disposed downstream of the fan section 102.

[0046] Figure 2 The turbine 104 depicted includes a tubular housing 106 (also referred to as a casing or nacelle) defining an inlet 108. In this embodiment, the inlet 108 is annular. The housing 106 encloses an engine core, which, in a series flow relationship, includes: a compressor section comprising a turbocharger or low-pressure (LP) compressor 110 and a high-pressure (HP) compressor 112; a combustion section 114; a turbine section comprising a high-pressure (HP) turbine 116 and a low-pressure (LP) turbine 118; and an exhaust nozzle section 120. The compressor section, combustion section 114, and turbine section together at least partially define a core airflow path 121 extending from the inlet 108 to the exhaust nozzle section 120. The turbine 104 further includes one or more drive shafts. More specifically, turbine 104 includes a high-pressure (HP) shaft or spool 122 that drives an HP turbine 116 to an HP compressor 112, and a low-pressure (LP) shaft or spool 124 that drives an LP turbine 118 to an LP compressor 110.

[0047] The ductless single-fan engine 100, more specifically, the turbine 104, is capable of operating in conjunction with the fuel system 130 and receives a fuel flow from the fuel system 130. The fuel system 130 includes a fuel delivery assembly 133 that supplies a fuel flow from a fuel tank 131 to the ductless single-fan engine 100, and more specifically, to a plurality of fuel nozzles 142 that inject fuel into the combustion chamber of the combustor 140 in the combustion section 114. The fuel delivery assembly 133 includes pipes, conduits, ducts, etc., to fluidly connect various components of the fuel system 130 to the ductless single-fan engine 100. The fuel tank 131 is configured to store hydrocarbon fuel, and hydrocarbon fuel is supplied from the fuel tank 131 to the fuel delivery assembly 133. The fuel delivery assembly 133 is configured to deliver hydrocarbon fuel between the fuel tank 131 and the ductless single-fan engine 100, thus providing a flow path (fluid path) for hydrocarbon fuel from the fuel tank 131 to the ductless single-fan engine 100.

[0048] Fuel system 130 includes at least one fuel pump fluidly connected to fuel delivery assembly 133 to direct fuel flow through fuel delivery assembly 133 to the ductless single-fan engine 100. One such pump is a main fuel pump 135. The main fuel pump 135 is a high-pressure pump and is the primary source of pressure increase in the fuel delivery assembly 133 between fuel tank 131 and the ductless single-fan engine 100. The main fuel pump 135 can be configured to increase the pressure in the fuel delivery assembly 133 to a pressure higher than the pressure inside the combustion chamber of burner 140.

[0049] Fuel system 130 also includes a fuel metering unit 137 in fluid communication with fuel delivery assembly 133. Any fuel metering unit 137 can be used, including, for example, a metering valve. Fuel metering unit 137 is positioned downstream of main fuel pump 135 and upstream of fuel manifold 139, which is configured to dispense fuel to fuel nozzles 142. Fuel system 130 is configured to supply fuel to fuel metering unit 137, and fuel metering unit 137 is configured to receive fuel from fuel tank 131. Fuel metering unit 137 is further configured to supply fuel flow to ductless single-fan engine 100 in a desired manner. More specifically, fuel metering unit 137 is configured to meter fuel and supply a desired amount of fuel to fuel manifold 139 of ductless single-fan engine 100 at, for example, a desired flow rate. Fuel manifold 139 is fluidly connected to fuel nozzles 142 and dispenses (provides) the received fuel to a plurality of fuel nozzles 142, where fuel is injected into a combustion chamber and burned. The regulating fuel metering unit 137 changes a certain amount of fuel supplied to the combustion chamber, thus changing the amount of propulsive thrust generated by the ductless single-fan engine 100 to propel the aircraft 10.

[0050] The ductless single-fan engine 100 also includes various auxiliary systems to assist in the operation of the ductless single-fan engine 100 and / or the aircraft 10. For example, the ductless single-fan engine 100 may include various auxiliary systems. Figure 2The diagram schematically depicts a main lubrication system 152, a compressor cooling air (CCA) system 154, an active thermal gap control (ATCC) system 156, and a generator lubrication system 158. The main lubrication system 152 is configured to provide lubricant to various bearings and gear meshes in, for example, the compressor section, turbine section, HP spool 122, and LP spool 124. The lubricant provided by the main lubrication system 152 can increase the service life of these components and can remove a certain amount of heat from these components by using one or more heat exchangers. The compressor cooling air (CCA) system 154 supplies air from one or both of the HP compressor 112 or the LP compressor 110 to one or both of the HP turbine 116 or the LP turbine 118. The active thermal gap control (ATCC) system 156 operates during flight missions as the casing temperature changes to minimize the clearance between the turbine blade tips and the casing wall. The generator lubrication system 158 provides lubrication to an electric generator (not shown) and provides cooling / heat dissipation for the electric generator. An electric generator can supply power to, for example, a starter motor for the ductless single-fan engine 100 and / or various other electronic components of the ductless single-fan engine 100 and / or the aircraft 10. The lubrication system for the ductless single-fan engine 100 (e.g., the main lubrication system 152 and the generator lubrication system 158) can use a hydrocarbon fluid such as oil for lubrication, wherein the oil circulates through the inner surface of an oil scavenge line.

[0051] The fan section 102 of the ductless single-fan engine 100 includes a plurality of fan blades 162 coupled to a fan hub 164 (or disc). The fan blades 162 and the fan hub 164 are circumferentially rotatable together about a rotation axis 161, which in this embodiment coincides with a longitudinal centerline (axis) 101. In this embodiment, a rotator 160 is connected to the fan hub 164 and rotates relative to the housing 106. Each fan blade 162 is an airfoil, more specifically, a rotating airfoil. In this embodiment, the fan blade 162, together with the fan hub 164, includes a rotating airfoil assembly.

[0052] The turbine 104 in this embodiment is a torque-generating system that generates torque to rotate the fan blades 162. The turbine 104 is configured to operate (e.g., rotate) the fan hub 164. The fan hub 164 may be coupled to a shaft of the turbine 104, more specifically, to an LP shaft 124 of the turbine 104, and the LP shaft 124 rotates the fan blades 162 and the fan hub 164. In some embodiments, the LP shaft 124 may be coupled to the fan hub 164 in a direct-drive configuration; however, in this embodiment, the LP shaft 124 is coupled to a reduction gearbox 126, which in turn transmits rotational (torsional) force to rotate the fan hub 164. The reduction gearbox 126 may be configured to reduce the input speed from the LP shaft 124 to a speed suitable for rotating the fan blades 162.

[0053] One or more outlet guide vanes 166 may be coupled to the housing 106. In this embodiment, the outlet guide vanes 166 are positioned behind the fan blades 162. In this embodiment, the housing 106 is stationary such that the one or more outlet guide vanes 166 do not rotate about the longitudinal centerline 101, and are therefore stationary relative to rotation about the longitudinal centerline 101. Although the outlet guide vanes 166 are stationary relative to the longitudinal centerline 101, the outlet guide vanes 166 are capable of rotation or movement relative to the housing 106.

[0054] During the operation of the ductless single-fan engine 100, air from... Figure 2 The left side flows towards Figure 2 On the right side. A portion of the airflow can flow over the fan blades 162 and the outlet guide vanes 166. A portion of the airflow can enter the housing 106 through the annular inlet 108, flow through the core airflow path 121 to mix with fuel for combustion in the combustor 140, and be discharged through the exhaust nozzle section 120. As described above, the outlet guide vanes 166 are movable relative to the housing 106 to guide the airflow in a specific direction. Each outlet guide vane 166 can be movable to adjust the tilt, pitch, sweep, or any combination thereof of the outlet guide vane 166.

[0055] exist Figure 1 and 2In the illustrated embodiment, the front end or front portion of the housing 106 includes one or more fan blades 162 and one or more outlet guide vanes 166. In other embodiments, the one or more fan blades 162 and one or more outlet guide vanes 166 may have different arrangements relative to the housing 106. For example, the one or more fan blades 162 and one or more outlet guide vanes 166 may be located at the rear end or rear portion of the housing 106, such as being coupled to the rear portion of the housing 106. More specifically, the one or more fan blades 162 and one or more outlet guide vanes 166 may be coupled to the rear portion of the housing 106.

[0056] In other embodiments, the engine according to this disclosure can be configured to have stationary blades positioned in front of the rotating fan blades 162 (therefore, blade 166 is an inlet guide blade). Although, as described above, the outlet guide blades 166 may be stationary and not rotate about the longitudinal centerline 101, one or more outlet guide blades 166 may rotate opposite to one or more fan blades 162, such that the one or more outlet guide blades 166 are counter-rotating rotors in a counter-rotating open rotor (CROR) engine. A propeller configuration in which the rotor is in front of the pylon 18 or an extender configuration in which the rotor is behind the pylon 18 is contemplated. In this case, the counter-rotating rotor may also be a rotating airfoil as part of a rotating airfoil assembly, as discussed further below.

[0057] Engine 100 also includes engine controller 170, which is configured to operate various systems of engine 100, such as, as discussed below, the rotation of engine 100, fan section 102, and / or fan blades 162. In this embodiment, engine controller 170 is a computing device having one or more processors 172 and one or more memories 174. Processor 172 can be any suitable processing device, including but not limited to microprocessors, microcontrollers, integrated circuits, logic devices, programmable logic controllers (PLCs), application-specific integrated circuits (ASICs), and / or field-programmable gate arrays (FPGAs). Memory 174 can include one or more computer-readable media, including but not limited to non-transient computer-readable media, computer-readable non-volatile media (e.g., flash memory), RAM, ROM, hard disk drives, flash drives, and / or other storage devices.

[0058] Memory 174 may store information accessible to processor 172, including computer-readable instructions executable by processor 172. Instructions may be any set or sequence of instructions that, when executed by processor 172, cause processor 172 and engine controller 170 to operate. In some embodiments, instructions may be executed by processor 172 to cause processor 172 to perform any operations and functions for which engine controller 170 is constructed, as will be further described below. Instructions may be software written in any suitable programming language or may be implemented in hardware. Additionally and / or alternatively, instructions may be executed in logically and / or virtually decoupled threads on processor 172. Memory 174 may further store data accessible by processor 172.

[0059] Engine controller 170 can be directly communicatively coupled to sensor 176 to receive various inputs, such as sensors monitoring the operation of engine 100 and / or aircraft 10. Engine controller 170 can also be indirectly coupled to such sensors and receive inputs from another source, such as the flight controller of aircraft 10. Engine controller 170 can be communicatively coupled to other controllers (such as the flight controller) and exchange data and commands with these other controllers. Therefore, engine controller 170 can receive various inputs, data, and commands from these other controllers.

[0060] The techniques discussed herein refer to computer-based systems and the actions taken by computer-based systems, as well as the information sent to and from computer-based systems. Those skilled in the art will recognize that the inherent flexibility of computer-based systems allows for a vast number of possible configurations, combinations, and divisions of tasks and functions between and within components. For example, the processes discussed herein can be implemented using a single computing device or multiple computing devices working in combination. Databases, memories, instructions, and applications can be implemented on a single system or distributed across multiple systems. Distributed components can operate sequentially or in parallel.

[0061] Figure 1 and 2The example of the rotating airfoil assembly shown is the fan blade 162 together with the fan hub 164, but the embodiments discussed herein can be applied to other rotating airfoil assemblies. Other rotating airfoil assemblies include, for example, propeller assemblies, such as those for turboprop engines. Such propeller assemblies may include multiple propeller blades coupled to and extending outward from a propeller shaft. The propeller assembly of a turboprop engine may be driven by a turbine (similar to turbine 104 discussed above) to rotate about the axis of rotation of the propeller shaft. The propeller blades are airfoils, more specifically, rotating airfoils, and the propeller assembly is another example of a rotating airfoil assembly. The propeller assembly is an open rotor system that may also be subjected to asymmetric loading on the propeller blades, wherein the longitudinal centerline of the turboprop engine is angled (e.g., pitched up or down) relative to the airflow entering the propeller assembly.

[0062] The above discussion is used for Figures 1 to 2 The torque generation system of the engine 100 shown is a turbine 104. However, other suitable torque generation systems can be used to rotate the rotating airfoil (e.g., fan blade 162) and the rotating airfoil assembly (e.g., fan hub 164 and fan blade 162). Other suitable torque generation systems include other engines, such as reciprocating engines. Although... Figure 1 The aircraft 10 shown is an airplane, but the embodiments described herein can also be applied to other aircraft 10, such as other fixed-wing unmanned aerial vehicles (UAVs).

[0063] Figure 3 An engine mounting system 200 is shown that can be used to mount engine 100 to aircraft 10. Figure 3 This is a cross-sectional view of the engine mounting system 200. The engine mounting system 200 includes an engine support structure 210. The engine support structure 210 may be a pylon 18 extending from the aircraft 10, such as from the fuselage 12, wing 14, or tail 16 of the aircraft 10 (see...). Figure 1 In this embodiment, the engine 100 is attached to one of the wings 14 in an underwing configuration via a pylon 18 (engine support structure 210), and the engine support structure 210 extends downward below the wing 14. The engine mounting system 200 includes a plurality of mounting members that connect the engine 100 to the engine support structure 210. In this embodiment, the engine mounting system 200 includes a front mounting member 220 and a rear mounting member 230. The engine 100 includes a plurality of frames, including a front frame 182 (see...). Figure 4 ) and rear frame 184 (see Figure 5The housing 106 may be connected to the front frame 182 and the rear frame 184. In some embodiments, the front frame 182 may be disposed generally around the compressor section of the turbine 104, and the rear frame 184 may be disposed generally around the turbine section of the turbine 104. The housing 106 may sometimes be referred to as the skeleton of the engine 100.

[0064] Figure 4 It is a display Figure 3 Detail 4 shows a cross-sectional detailed view of the front mount 220. While any suitable mount can be used, the front mount 220 of this embodiment includes a front mount beam 222 attached to the front section 212 of the engine support structure 210. The front mount beam 222 is attached to the engine support structure 210 using any suitable means, such as fasteners. In this embodiment, a plurality of bolts 224 are used to attach the front mount beam 222 to the engine support structure 210. The front mount beam 222 includes a spherical single-ball bearing 226 attached to the front end of the front mount beam 222. In this embodiment, a mounting lug 186 integrally formed with the front frame 182 is connected to and engages with the single-ball bearing 226 to connect the front frame 182, and thus the engine 100, to the front mount beam 222.

[0065] Figure 5 It is a display Figure 3 Detail 5 shows a cross-sectional detailed view of the rear mount 230. While any suitable mount can be used, the rear mount 230 of this embodiment includes a platform 232 attached to the rear section 214 of the engine support structure 210. The platform 232 is attached to the engine support structure 210 using any suitable means, such as fasteners. In this embodiment, a plurality of bolts 224 are used to attach the front mount beam 222 to the engine support structure 210. The platform 232 includes a platform clamp 234 attached to the platform 232. In this embodiment, the platform clamp 234 is integrally formed with the platform 232. The rear frame 184 also includes a clevis, here a frame clamp 188, which in this embodiment is integrally formed with the rear frame 184. The rear frame 184 is connected to the platform 232 via a mounting link 236. The mounting link 236 may be a rod or plate with holes formed therein. Bolt 224 is inserted through one of the holes formed in the frame clamp 188 and the mounting rod 236 to connect the mounting rod 236 to the rear frame 184, and another bolt 224 is inserted through one of the holes formed in the platform 232 and the mounting rod 236 to connect the mounting rod 236 to the platform 232.

[0066] The aircraft 10 changes its pitch angle throughout flight. The pitch angle of the aircraft 10 can be the angle between the horizontal line (horizontal plane) and the centerline 26 of the aircraft 10. The pitch angle of the aircraft 10 can be small for states such as cruise or idling, and large for takeoff, climb, and dive. Figure 6 The aircraft 10 is shown during level flight (such as during cruise). Fan blades 162 rotate about an axis of rotation 161 in a plane of rotation 168, and the airflow 32 entering fan section 102 is generally perpendicular to the plane of rotation 168 and parallel to the axis of rotation 161. In this embodiment, the axis of rotation 161 is also parallel to both the longitudinal centerline 101 of the engine 100 and the centerline 26 of the aircraft 10. Therefore, the airflow 32 is also parallel to both the longitudinal centerline 101 of the engine 100 and the centerline 26 of the aircraft 10.

[0067] Figure 7 The image shows an aircraft 10 pitching upwards, such as during takeoff or climb. When the aircraft 10 has a pitch angle, such as when the nose 22 pitches upwards during takeoff or climb, the aircraft 10 may have an angle of attack (angle α). Angle of attack (AOA) is the angle α between the oncoming air or relative wind (airflow 32) and a reference line on the aircraft 10. In some embodiments, the reference line is a line connecting the leading and trailing edges at an average point on the wing 14. In other embodiments, such as for commercial airliners, the centerline 26 may be the reference line. Without altering the plane of rotation 168 and / or the axis of rotation 161, the airflow 32 flows into the fan section 102 at an angle of inclination relative to both the axis of rotation 161 and the plane of rotation 168, causing the following... Figure 8 Further discussion on the 1P loading status.

[0068] Figure 8 The rotating airfoil assembly 190, including the rotating airfoil 194, is shown. Figure 3 The rotating airfoil assembly 190 depicted in the image is Figure 1 and 2 The fan blades 162 and fan hub 164 of the ductless single-fan engine 100, and Figure 8 This is a front view of the rotator 160. The rotator airfoil 194 (fan blade 162) of the rotator airfoil assembly 190 is... Figure 8 The rotating airfoil 194 rotates clockwise about the rotation axis 192 (rotation axis 161). For the convenience of the following discussion, the angular positions of the rotating airfoil 194 and the rotating airfoil assembly 190 are given relative to the rotation axis 192, as follows: Figure 8 As shown. Therefore, the rotating airfoil 194 rotates from zero degrees to 180 degrees in the downward direction and from 180 degrees to 360 degrees (zero degrees) in the upward direction.

[0069] Figure 8 The axis of rotation 192 (e.g., pitching up or down) is shown at an angle relative to the airflow 32 entering the rotating airfoil 194. More specifically, in Figure 8 In the middle, the axis of rotation 192, such as in Figure 7 During the state shown, the airflow 32 entering the rotating airfoil 194 is angled upwards. In this state, the rotating airfoil assembly 190 experiences a non-axial component of the airflow in the upward direction (as depicted by the upward arrow). Each rotating airfoil 194 generates similar lift at the top (zero degrees) and bottom (180 degrees) of rotation as it would when the rotating airfoil assembly 190 is not tilted. However, each rotating airfoil 194 generates less lift as it moves downwards from the top (zero degrees) to the bottom (180 degrees) and more lift as it moves upwards from the bottom (180 degrees) to the top (zero degrees). This variation in lift is caused by… Figure 8 The dashed lines in the diagram illustrate this. When the rotating airfoil 194 rotates one revolution, the minimum lift generated by the rotating airfoil 194 is at 90 degrees. As the rotating airfoil 194 continues to rotate, the lift steadily increases from that point to 270 degrees, and then steadily decreases. This can be referred to as a load per revolution or a 1P load.

[0070] Although, as described above, the rotating airfoil assembly 190 can be various suitable rotating airfoil assemblies 190, the embodiment depicted in the figures shows a ductless single-fan engine 100, where the rotating airfoil assembly 190 is the fan section 102, and more specifically, the fan blades 162 and the fan hub 164. Therefore, the discussion herein refers to the ductless single-fan engine 100, but this discussion is equally applicable to other rotating airfoil assemblies 190, and to rotating airfoils 194 other than the fan blades 162 and fan hub 164 specifically discussed herein.

[0071] Figure 9 An aircraft 10 with a fan section 102, according to an embodiment, is shown, exhibiting upward pitch (such as during takeoff or climb). To eliminate the 1P loading state, the aircraft 10 is configured to alter the plane of rotation 168, thereby eliminating or reducing the non-axial component of the airflow discussed above. Figure 9In the depicted embodiment, the engine 100 is rotated to change the plane of rotation 168 such that even when the aircraft 10 has an angle of attack (angle α), the airflow 32 is substantially perpendicular to the plane of rotation 168 and parallel to the axis of rotation 161. In some embodiments, such as when the aircraft 10 has a high angle of attack (angle α), the aircraft 10 may change the plane of rotation 168 to such an extent that the airflow 32 still has an angle of inclination with the plane of rotation 168, the axis of rotation 161, and / or the longitudinal centerline 101 of the engine 100, but the angle of inclination is reduced, thereby reducing the non-axial component of the airflow.

[0072] Engine controller 170 may be configured to receive inputs and determine from these inputs that the aircraft 10 has an angle of attack (angle α). In some embodiments, engine controller 170 is configured to receive inputs indicating the pitch angle of the aircraft 10 and determine the angle of attack (angle α) of the aircraft 10 based on the pitch angle of the aircraft 10. As discussed above, engine controller 170 may be directly or indirectly communicatively coupled to sensor 176, such as a gyroscope or other suitable sensor, to determine whether the aircraft 10 is pitching up or down, and engine controller 170 is configured to receive inputs from sensor 176 indicating the pitch angle of the aircraft 10. Sensor 176 may be located on engine 100 and / or on another part of aircraft 10, such as on fuselage 12, wing 14, and / or tail 16. Engine controller 170 may use additional inputs from other sensors, such as load cells, strain gauges, pressure sensors, etc. The aircraft 10, and more specifically, the engine 100, includes at least one actuator 202 operable to change the plane of rotation 168. An engine controller 170 is operatively coupled to the at least one actuator 202 and configured to operate the at least one actuator 202 to change the plane of rotation 168 based on the angle of attack (angle α). Specific mechanisms for changing the plane of rotation 168 will be further discussed below. In some embodiments, the at least one actuator 202 is configured to adjust (change) the angle of the axis of rotation 161. In some of these embodiments, the at least one actuator 202 rotates the entire engine 100 (e.g., rotates the fan section 102 together with the turbine 104), but in other embodiments, the at least one actuator 202 rotates only a portion of the engine 100 (such as the fan section 102). In a further embodiment, the at least one actuator 202 pivots each fan blade 162 as the fan blades 162 rotate about the axis of rotation 161. In the embodiments discussed herein, rotational movement is in the pitch direction of the aircraft 10.

[0073] Figure 10 , 11Figures 1 and 12 show the engine support structure 210 according to an embodiment. Figure 1 (Hanger 18). Figure 10 This is a top view of the engine support structure 210, and Figure 11 and 12 It is along Figure 1 The diagram shows a schematic cross-sectional view of the engine 100 and engine support structure 210, taken from line 2-2. In this embodiment, the engine support structure 210 is extendable between a retracted position and an extended position. Figure 10 and 11 The engine support structure 210 is shown in its retracted position, and Figure 12 The engine support structure 210 in the deployed position is shown. In this embodiment, the engine support structure 210 includes a front strut 241 and a rear strut 243. The front strut 241 is pivotable relative to the rear strut 243, and the rear strut 243 is stationary and remains connected to the wing 14 (see...). Figure 1 At least one actuator 202, and in this embodiment, two actuators 202 are connected to each of the front strut 241 and the rear strut 243. The actuators 202 extend in a forward direction and retract in a rearward direction. Extending the actuators 202 from the retracted position moves the front strut 241 away from the rear strut 243. The actuators 202 can be any suitable actuator, including, for example, linear actuators such as hydraulic cylinders.

[0074] The front strut 241 and rear strut 243 engage with each other such that when the actuator 202 extends, the front strut 241 also bends and rotates the engine 100, thereby rotating the longitudinal centerline 101 about the pitch direction. In this embodiment, the front portion 245 of the rear strut 243 bends in a downward direction and includes a bending groove 247. The front strut 241 includes an engaging strut 249 on the rear portion of the front strut 241. The engaging strut 249 engages with the bending groove 247 and guides the rotation of the front strut 241 when the actuator 202 extends or retracts. The front mount 220 and rear mount 230 can each be configured to allow rotation about the pitch axis of the aircraft 10, such as by changing the frame clamp 188 ( Figure 5 ) and platform fixture 234 ( Figure 5 The orientation of the front mount 220 allows for rotation. With the front mount 220 attached to the front strut 241 and the rear mount 230 attached to the rear strut 243, the engine support structure 210 extends to maintain a constant distance between the front mount 220 and the rear mount 230.

[0075] When the aircraft 10 pitches upwards, the fan blades 162 and the airflow 32 ( Figure 7When an angle of attack (angle α) is formed between the airflow 32 and the fan blades 162, the engine controller 170 is configured to extend the actuator 202, thereby pivoting the engine 100, and more specifically, pivoting the rotation axis 161 and the longitudinal centerline 101 of the engine 100 downwards relative to the centerline 26 of the aircraft 10. Preferably, the engine controller 170 will extend the actuator 202 such that the rotation axis 161 is parallel to the airflow 32 and the rotation plane 168 is perpendicular to the airflow 32. Therefore, the fan blades 162 will not be subjected to the non-axial component of the airflow 32, and the 1P load can be eliminated or reduced.

[0076] Figure 13 and 14 An engine support structure 210 according to another embodiment is shown. Figure 1 (Hanger 18). Figure 13 This is a side view of the engine support structure 210, and Figure 14 This is a top view of the engine support structure 210. (And...) Figures 10 to 12 The embodiment shown is similar, employing a two-piece engine support structure 210 with a front strut 241 and a rear strut 243. The front strut 241 pivots relative to the rear strut 243, thus enabling operation to move the engine 100, as described above relative to... Figures 10 to 12 The embodiments shown are discussed. However, in this embodiment, both the front mount 220 and the rear mount 230 are attached to the front strut 241.

[0077] The front strut 241 is attached to the rear strut 243 via at least one pivot 252. In this embodiment, multiple pivots 252 are used. The pivots 252 are located on the lower portion of each of the front strut 241 and the rear strut 243. At least one actuator 202 is connected to the upper portion of each of the front strut 241 and the rear strut 243. In this embodiment, multiple actuators 202 are used. Extending or retracting the actuator 202 causes the front strut 241 to pivot about the pivot 252 to change the angle of the engine 100. As discussed above, the actuator 202 can be any suitable actuator, and in this embodiment, the actuator 202 is preferably a drive screw.

[0078] Figure 15 , 16 17 shows an engine support structure 210 according to another embodiment. Figure 1 (Hanger 18). Figure 15 This is a side view of the engine support structure 210. Figure 16 It is along Figure 15 The cross-sectional view of the rear mount 230 taken from line 16-16 in the figure, and Figure 17 It is along Figure 16The image shows a cross-sectional view of the rear mount 230 taken along line 17-17. In the aforementioned embodiment, the engine support structure 210 is movable to pivot the engine 100 and change the plane of rotation 168 relative to the aircraft 10. In this embodiment, the engine support structure 210 is stationary, and at least one of the front mount 220 and the rear mount 230 is a movable mount that translates vertically to pivot the engine 100 and change the plane of rotation 168 relative to the aircraft 10, similar to the embodiments discussed above.

[0079] exist Figure 15 , 16 In the embodiment shown in Figure 17, the rear mount 230 is movable, and more specifically, the platform 232 is movable. In this embodiment, the platform 232 is a plate oriented in both the longitudinal and vertical directions, with the thickness direction oriented in the inner and outer directions of the aircraft 10. In this embodiment, the platform clamp 234 protrudes outward (or inward). The platform 232 may have other orientations. The platform 232 is movable vertically, and the platform 232 is positioned within a channel 254 to guide the platform 232 during vertical movement. The channel 254 includes an opening 256 for the platform clamp 234. A plurality of actuators 202 are used to move the platform 232 vertically. In this embodiment, two actuators 202 are located on the upper side of the platform 232, and two actuators 202 are located on the lower side of the platform 232. Although any suitable actuator 202 can be used as described above, the actuator 202 in this embodiment is preferably a drive screw. Raising the rear mount 230 (moving the rear mount 230 upwards), more specifically, raising the platform 232, raises the rear frame 184 and the rear portion of the engine 100, thereby causing the fan section 102 and the plane of rotation 168 to pivot downwards, as... Figure 9 As shown. The engine controller 170 can be configured to raise and lower the rear mount 230 in a manner similar to that discussed above.

[0080] Figure 18 An engine support structure 210 according to another embodiment is shown. Figure 1 (Hanger 18). Figure 18This is a side view of the engine support structure 210. In this embodiment, the front mount 220 is movable in the vertical direction. The front mount 220, more specifically, the front mount beam 222, is pivotally attached to the engine support structure 210 via a suitable pivot 262, such as a clamp and pin connection. At least one actuator 202 is connected to the front mount beam 222 in front of or behind the pivot 262 to pivot the front mount beam 222 about the pivot 262. In this embodiment, the actuator 202 is a linear actuator, such as a drive screw. The front portion of the front mount 220 is pivoted, and more specifically, the front mount beam 222 is pivoted downwards, causing the front frame 182 ( Figure 4 The front portion of the engine 100 moves downward, thereby pivoting the fan section 102 and the plane of rotation 168 downward, as shown. Figure 9 As shown. The engine controller 170 can be configured to pivot the front mount 220 in a manner similar to that discussed above.

[0081] Figure 19 An engine support structure 210 according to another embodiment is shown. Figure 1 (Hanger 18). Figure 19 This is a side view of the engine support structure 210. This embodiment is similar to the one mentioned above. Figure 18 The discussed embodiments are similar, but instead of the linear actuator 202, a rotatable cam 264, such as a rotatable eccentric cam, is used to pivot the front mount 220. The rotatable cam 264 can be positioned in front of or behind the pivot 262, and rotating the rotatable cam 264 rotates the front portion of the front mount beam 222. To bring the front mount beam 222 and the engine support structure 210 into contact with each other, a spring 266 is positioned in a balanced arrangement on the side of the pivot 262 opposite to the rotatable cam 264, and applies a biasing (balancing) force to the front mount beam 222. While the spring 266... Figure 19 The bias (balancing) force is shown in the figure, but other suitable devices can be used to apply the bias (balancing) force, such as spring / damper arrangements.

[0082] Figure 20 This is a schematic cross-sectional view of an engine 100 according to another embodiment. In the embodiment discussed above, the entire engine 100 is rotated to change the engine 100; however, in this embodiment, only a portion of the engine 100 is rotated, specifically, the fan section 102 is rotated. In this embodiment, actuator 202 is used to pivot the fan section 102, and more specifically, to pivot the fan blades 162 and the fan hub 164, so as to rotate the axis of rotation 161 and the plane of rotation 168. Engine controller 170 is configured to operate actuator 202 in a similar manner to that discussed above, and engine controller 170, together with actuator 202, is configured to change the pitch angle of fan section 102.

[0083] The fan section 102, including the rotator 160, fan blades 162, and fan hub 164, is pivotally connected to the outer casing 106 of the turbine 104. Any suitable pivotable connection can be used, such as a curved slot allowing pitch variation, or, as in this embodiment, a ball joint 272. As discussed above, the fan hub 164 is coupled to the LP shaft 124 of the turbine 104, and the LP shaft 124 rotates the fan blades 162 and the fan hub 164. The LP shaft 124 is an example of the output shaft of the turbine 104 (torque generation system). In this embodiment, the fan hub 164 is connected to the fan shaft 169, and the LP shaft 124 is connected to the fan hub 164 via a differential gearbox 274. The fan shaft 169 is an example of the input shaft of the rotating airfoil assembly 190. The differential gearbox 274 is centered within the ball joint 272 and allows the fan shaft 169 to be angled relative to the LP shaft 124 while still receiving rotational drive force from the LP shaft 124. The differential gearbox 274 is an example of a pivotable coupling between the LP shaft 124 and the fan shaft 169, allowing the LP shaft 124 to change its pitch angle relative to the fan shaft 169. The fan shaft 169 may be supported by a cylindrical bearing 276 to allow load transfer and also to allow pitch and rotation.

[0084] As mentioned above Figure 2 The aforementioned reduction gearbox 126 can be used to connect the LP shaft 124 to the fan hub 164 and fan blades 162. Figure 20 In some embodiments, a differential gearbox 274 can be used instead of a reduction gearbox 126 and is configured to reduce the input speed from the LP shaft 124 to a speed suitable for rotating the fan hub 164 and the fan blades 162. Alternatively, a differential gearbox 274 can be used in addition to the reduction gearbox 126, and in this case, the reduction gearbox 126 can be located in the drivetrain between the differential gearbox 274 and the LP shaft 124.

[0085] Figure 21 Showing Figure 20 The differential gearbox 274 includes an input gear 274a connected to the LP shaft 124 and an output gear 274b connected to the fan shaft 169. The input gear 274a and output gear 274b each engage with a pair of drive gears 274c to transmit torque from the input gear 274a to the output gear 274b. For clarity, other drive gears 274c have been removed. Figure 21Only one drive gear 274c is shown. Each drive gear 274c rotates about the same axis and both are positioned opposite each other on opposite sides of the input gear 274a and the output gear 274b. The differential gearbox 274 is configured to allow the fan shaft 169 and the output gear 274b to rotate and engage with the drive gear 274c at different radial positions, thereby allowing the fan section 102 to change angles, as described above.

[0086] Figure 22 This is a schematic cross-sectional view of an engine 100 according to another embodiment. (Refer to above) Figure 20 In the discussed embodiment, the LP shaft 124 is connected to the fan shaft 169 via a differential gearbox 274, but other suitable connections may be used. In this embodiment, for example, the LP shaft 124 and fan shaft 169 are connected via a constant velocity (CV) joint 278 instead of a differential gearbox 274. The constant velocity (CV) joint 278 is another example of a pivotable coupling between the LP shaft 124 and the fan shaft 169. The constant velocity (CV) joint 278 allows power to be transmitted from the LP shaft 124 to the fan shaft 169 and accommodates rotation in the pitch direction of the fan section 102. The constant velocity (CV) joint 278 allows for a high articulation angle, thus enabling movement of the fan hub 164 and fan blades 162 over a wide range of angles of attack. The fan shaft 169 may be supported by bearings such as spherical bearings 279, as will be discussed further below. In this embodiment, two actuators 202 are shown connected to a spherical bearing 279 to move the fan shaft 169, thereby moving the fan hub 164 and the fan blades 162.

[0087] Figure 23 and 24 This is a detailed cross-sectional view showing the spherical bearing 279 that supports the fan shaft 169. Figure 20 In the illustrated embodiment, the cylindrical bearing 276 is used to support the fan shaft 169, but other bearings can be used. For example, a bearing such as... Figure 23 and 24 The spherical bearing 279 shown is an example. Compared to conventional radial bearings, the spherical bearing 279 allows for additional degrees of freedom. For instance, when the fan shaft 169 is moved by the actuator 202, the spherical bearing 279 allows the fan shaft 169 to pivot axially within the spherical bearing 279, as shown. Figure 24 As shown.

[0088] Figure 25 and 26This is a schematic cross-sectional view of engine 100 according to another embodiment. In the embodiments discussed above, engine controller 170 is configured to operate at least one actuator 202 to rotate engine 100 as a whole, such that the angle of longitudinal centerline 101 relative to aircraft 10 is changed, or to rotate fan segment 102, such that the axis of rotation 161 is changed relative to aircraft 10 and longitudinal centerline 101. In this embodiment, engine controller 170 is configured to operate at least one actuator 202 to change plane of rotation 168 to have the orientation discussed above, without changing the angle of longitudinal centerline 101 or axis of rotation 161 relative to aircraft 10. Instead, as fan blades 162 rotate about axis of rotation 161, the pitch angle (as used herein, forward / backward direction) of each fan blade 162 is changed. Figure 25 This shows the effects during level flight (such as those mentioned above). Figure 6 Engine 100 (under the conditions discussed). Figure 26 This shows what happens when aircraft 10 has an angle of attack (as shown above regarding...). Figure 7 and 8 Engine 100 (under the conditions discussed).

[0089] In this embodiment, each fan blade 162 is connected to the fan hub 164 via a pivotable connection that allows the fan blade 162 to change its pitch angle. In this embodiment, the pivotable connection includes an arcuate recess 280, and the fan blade 162 is configured to move back and forth within the arcuate recess 280. In this embodiment, each fan blade 162 is connected to a corresponding arcuate recess 280, but other arrangements may be used. The arcuate recess 280 is oriented in the longitudinal direction of the engine 100. At least one actuator 202, and in this embodiment, two actuators 202, are connected to the fan blade 162 to move the fan blade 162 forward and backward within the arcuate recess 280.

[0090] exist Figure 25 During the state shown, when the fan blade 162 rotates about the rotation axis 161, the actuator 202 holds the fan blade 162 in a fixed position, but in Figure 26 In the state shown, the engine controller 170 is configured to operate the actuator 202 to cause the fan blades 162 to move independently between the front portion and the rear portion of the arcuate recess 280. Each fan blade 162 is in the twelve o'clock position ( Figure 8 At zero degrees, it is located on the front portion 282 of the arc-shaped groove 280, but each fan blade 162 is at the six o'clock position ( Figure 8The fan blade 162 is located on the rear portion 284 of the arc-shaped groove 280 at 180 degrees. When the fan blade 162 rotates from the 12 o'clock position to the 6 o'clock position, the actuator 202 moves each fan blade 162 from the front portion 282 to the rear portion 284, and when the fan blade 162 rotates from the 6 o'clock position to the 12 o'clock position, the actuator 202 moves each fan blade 162 from the rear portion 284 to the front portion 282. The engine controller 170 can control the degree of forward and backward movement of each fan blade 162 to maintain a rotation plane 168 perpendicular to the airflow 32.

[0091] Figure 27 This is a detailed cross-sectional view of the fan hub 164 according to another embodiment. Above regarding... Figure 25 and 26 In the discussed embodiment, each fan blade 162 utilizes a pivotable connection within the arcuate groove 280 to change the pitch angle. Other suitable pivotable connections can be used, such as Figure 27 The connector shown is shown. The fan blade 162 includes a root 302, which includes a ball portion 304. The ball portion 304 is connected to the fan hub 164 via a trunnion 310, and the trunnion 310 secures the ball portion 304.

[0092] The fan blade 162 includes a longitudinal axis 306 extending radially from the fan hub 164. A plurality of radial bearings 312 connect the trunnion 310 to the fan hub 164 and allow the fan blade 162 to rotate about the longitudinal axis 306. This angular rotation of the fan blade 162 is referred herein as the airfoil pitch or airfoil angle of attack to distinguish this movement from the movement of the fan blade 162 about an axis parallel to the pitch axis of the aircraft 10.

[0093] In this embodiment, a plurality of spherical bearings 314 connect the trunnion 310 to the ball portion 304 and allow the ball portion 304 to change its pitch angle (forward and backward direction of the aircraft 10) in response to movement of at least one actuator 202, thereby allowing the fan blades 162 to change their pitch angle (forward and backward direction of the aircraft 10) in response to movement of at least one actuator 202. The actuator 202 is connected to the root portion 302 and is configured to move the root portion 302 in the forward and backward direction. The engine controller 170 can be configured to operate the actuator 202 in a manner similar to that described above. Figure 26 The method discussed involves changing the pitch angle of the fan blades 162 (the forward and backward direction of the aircraft 10).

[0094] Figure 28 It is along Figure 27The image shows a cross-sectional view of the root 302 of the fan blade 162, taken along lines 28-28. In this embodiment, the inner portion 308 of the root 302 extends below the ball portion 304 and enters a groove 316 formed in the trunnion 310. The size of the inner portion 308 relative to the groove 316 is determined to restrict movement in one direction, but with a gap to allow movement in another direction (front-back direction).

[0095] Figure 29 This is a cross-sectional view of the root 302 of the fan blade 162 according to another embodiment. In the embodiment discussed above, the pitch angle of the fan blade 162 relative to the pitch axis of the aircraft 10 is actively controlled by the engine controller 170. These active controls can be used alone or in combination with other methods to alleviate IP loading. In this embodiment, the fan blade 162 is equipped with a spring and damper system 320 for passively adjusting the airfoil pitch angle based on the load applied to the fan blade 162. As described above, the airfoil pitch angle, as used herein, is the angle of the fan blade 162 about the longitudinal axis 306 (see...). Figure 27 The rotation or angle of ).

[0096] Its top view is Figure 29 The fan blade 162, shown in dashed lines, has a leading edge 331 and a trailing edge 333. The chord 335 of the fan blade 162 extends from the leading edge 331 to the trailing edge 333. The fan blade 162 also includes a suction side and a pressure side, and surfaces of the fan blade 162 are formed on each of the suction side and the pressure side between the leading edge 331 and the trailing edge 333. These surfaces are a suction surface 337 and a pressure surface 339. (As shown in...) Figure 29 As can be seen, the fan blade 162 is a curved airfoil with a suction surface 337 and a pressure surface 339. The suction surface 337 has a convex curvature, and the pressure surface 339 is generally flat. However, the fan blade 162 can have any suitable shape, including concave surfaces, and the fan blade 162 can be a symmetrical airfoil. The suction surface 337 and the pressure surface 339 are positioned on opposite sides of the fan blade 162 such that when the airflow rotates with the fan blade 162 about the axis of rotation 161 above the suction surface 337 and the pressure surface 339 of the fan blade 162, the fan blade 162 generates lift (thrust).

[0097] A spring and damper system 320 is connected to the root 302, and more specifically, to the inner portion 308 of the root 302. The spring and damper system 320 is configured to apply force to the root 302 to cause the root 302 and the fan blades 162 to rotate about the longitudinal axis 306, adjusting the airfoil pitch angle in certain states, such as those discussed above. Figure 27 and 28Similarly, in the embodiment, the trunnion 310 is configured to actively rotate the fan blades 162 and serves as a pitch angle control mechanism to change the airfoil's angle of attack (angle β, see Figure 30 This allows for simultaneous control of the pitch angle of all blades (e.g., up to 45 degrees on either side of the neutral position). Therefore, the trunnion 310 can be used to control the thrust generated by the fan section 102. Figure 27 and 28 In contrast to the embodiment, slot 316 includes bearing 318, which restricts the free rotation of the internal portion 308 applied by the spring and damper system 320. The amount of rotation caused by the spring and damper system 320 is limited to a small amount, such as ten degrees from the airfoil angle of attack (angle β) set by the trunnion 310.

[0098] The spring and damper system 320 includes multiple dampers, including a large damper 321 and a small damper 323. In this embodiment, the large damper 321 and the small damper 323 are hydraulic dampers, but any suitable damper can be used, for example, including pneumatic dampers. The large damper 321 and the small damper 323 are each configured to apply a rotational force to the inward portion 308 to rotate the fan blade 162 about the longitudinal axis 306. The large damper 321 and the small damper 323 each include a piston 325. The piston 325 of the small damper 323 has a smaller surface area than the piston 325 of the large damper 321. The large damper 321 and the small damper 323 are fluidly connected to each other via a conduit 327, so that the pressure of the hydraulic fluid in each of the large damper 321 and the small damper 323 is the same. By utilizing the difference in surface area of ​​piston 325, the smaller damper 323 applies a smaller pressure load (force) than the larger damper 321. Figure 29 In the embodiment shown, the piston 325 of the small damper 323 has half the area of ​​the piston 325 of the large damper 321. Therefore, if the large damper 321 applies a force (pressure load) P to the inner portion 308, the small damper 323 applies a force (pressure load) of half P to the inner portion 308.

[0099] Large damper 321 and small damper 323 are positioned on opposite sides of the chord 335, and in this embodiment, large damper 321 is positioned on the pressure side and small damper 323 is positioned on the suction side. An opposite arrangement can also be used, where large damper 321 is positioned on the suction side and small damper 323 is positioned on the pressure side. Large damper 321 and small damper 323 are also positioned on opposite ends of the fan blade 162 (opposite sides of the inner portion 308) on either side of the longitudinal axis 306. In this embodiment, large damper 321 is positioned at the front end closer to the leading edge 331 than the trailing edge 333, and small damper 323 is positioned at the rear end closer to the trailing edge 333 than the leading edge 331. Other arrangements can be used, such as small damper 323 at the front end and large damper 321 at the rear end. Using this arrangement, the large damper 321 and the small damper 323 each apply a rotational force to the fan blade 162 in the same direction to change the airfoil's pitch angle. In this embodiment, the rotational force is in the direction that increases the airfoil's angle of attack (angle β).

[0100] The spring and damper system 320 also includes a spring 329 configured to balance the rotational forces exerted by the large damper 321 and the small damper 323. The spring 329 can be located in any suitable position to balance the rotational forces exerted by the large damper 321 and the small damper 323; however, in this embodiment, the spring 329 is located opposite the small damper 323 on the pressure side of the fan blade 162 and on the rear end of the fan blade 162. The spring 329 is configured to exert a rotational force toward the fan shaft (not shown), more specifically, toward the inner portion 308. The direction of rotation of the force exerted by the spring 329 is opposite to the direction of rotation of the large dampers 321 and 323. The spring 329 in this embodiment is a compression spring, but other suitable springs and arrangements can be used.

[0101] exist Figure 29 In the middle, fan blade 162 is stationary (not rotating), and... Figure 29 In the example shown, the large damper 321 applies a force P to the inner portion 308, and the small damper 323 applies a force of half P to the inner portion 308 for a total rotational force of one and a half P. As a result, the spring 329 is compressed to a point where the spring force C is equal to one and a half P.

[0102] Figure 30This is a cross-sectional view of the root 302 of fan blade 162, showing the state of fan blade 162 rotating about axis of rotation 161. Fan blade 162 has an airfoil angle of attack (angle β) with airflow 32. When fan blade 162 rotates, it generates a thrust with a resultant force F. Pressure regulation in large damper 321 balances the force F from the thrust on fan blade 162. Therefore, small damper 323 applies half of the rotational force F to fan blade 162, and fan blade 162 rotates to an airfoil pitch angle where the spring force balances the force half of the F. This is in the state of horizontal flight of aircraft 10, as described above. Figure 6 In the state shown, the thrust and resultant force F are constant with one rotation of the fan blade 162.

[0103] In the like above Figure 7 As shown, in the state with a non-axial component of airflow, the thrust and resultant force F change with the rotation of the fan blade 162. When the fan blade 162 moves through the rotating portion where the resultant force F increases, the small damper 323 will also apply an additional force to the inner portion 308, causing the fan blade 162 to rotate in the direction that increases the airfoil angle of attack (angle β). When the airfoil angle of attack (angle β) increases, the thrust generated by the fan blade 162 decreases. When the fan blade 162 moves through the rotating portion where the resultant force F decreases, the small damper 323 will apply a smaller force to the inner portion 308, and the spring 329 will cause the fan blade 162 to rotate in the direction that decreases the airfoil angle of attack (angle β). When the airfoil angle of attack (angle β) decreases, the thrust generated by the fan blade 162 increases. Thus, it is possible to... Figure 31 As shown, this reduces the cyclic load on fan blade 162.

[0104] Figure 31 This shows when fan blade 162 is in Figure 8 The load on the fan blade 162 during one revolution in the illustrated state. The dashed line shows one rotation of the fan blade 162 without the spring and damper system 320, and the solid line shows one rotation of the fan blade 162 with the spring and damper system 320. Figure 31 As can be seen, the use of the spring and damper system 320 reduces the cyclic load on the fan blades 162.

[0105] The embodiments discussed herein reduce the magnitude of asymmetric loads generated by rotating airfoils, or even eliminate asymmetric loads when the aircraft has an angle of attack. Further aspects of this disclosure are provided in the subject matter of the following provisions.

[0106] An airfoil structure includes an airfoil and a spring and damper system. The airfoil includes a longitudinal axis, and the spring and damper system is connected to the airfoil to rotate the airfoil about the longitudinal axis, thereby changing the airfoil's pitch angle in response to a load applied to the airfoil.

[0107] According to the airfoil structure described in the foregoing clauses, the spring and damper system includes a plurality of dampers. Each of the plurality of dampers is fluidly connected to each other and is configured to apply a rotational force to the rotating airfoil in a first direction.

[0108] According to any one of the preceding clauses, in the airfoil structure, each of the plurality of dampers is a hydraulic damper.

[0109] According to any one of the foregoing clauses, the airfoil structure wherein the spring and damper system includes a spring configured to balance the rotational force applied by the plurality of dampers.

[0110] The airfoil structure according to any one of the foregoing clauses, wherein the airfoil further includes a root, and the plurality of dampers and the spring are connected to the root to apply the rotational force to the root.

[0111] The airfoil structure according to any one of the foregoing clauses further includes a trunnion, the trunnion comprising a bearing. The root includes a ball portion fixed in the trunnion by the bearing to allow the ball portion to rotate about the longitudinal axis.

[0112] According to any one of the foregoing clauses, in the airfoil structure, the root includes an inner portion extending below the ball portion and entering a groove formed in the trunnion. The plurality of dampers and the spring are connected to the inner portion of the root.

[0113] According to any one of the foregoing clauses, in the airfoil structure, each of the plurality of dampers includes a piston. The plurality of dampers includes a large damper and a small damper. The piston of the small damper has a smaller surface area than the piston of the large damper.

[0114] According to any one of the preceding clauses, the airfoil structure wherein the small damper applies a smaller pressure load to the airfoil than the large damper.

[0115] According to any one of the foregoing clauses, the airfoil structure further includes a leading edge, a trailing edge, and a chord extending from the leading edge to the trailing edge. The large damper and the small damper are positioned on opposite sides of the chord.

[0116] According to any one of the foregoing clauses, in the airfoil structure, the spring and damper system includes a spring configured to balance the rotational force applied by the plurality of dampers. The spring and the large damper are positioned on the same side of the airfoil chord.

[0117] The airfoil structure according to any one of the foregoing clauses, wherein the airfoil further comprises a pressure side and a suction side. The large damper is located on the pressure side, and the small damper is located on the suction side.

[0118] According to any one of the foregoing clauses, in the airfoil structure, the spring and damper system includes a spring configured to balance the rotational force applied by the plurality of dampers. The spring is positioned on the pressure side.

[0119] According to any one of the foregoing clauses, the airfoil structure wherein the large damper and the small damper are positioned on opposite sides of the longitudinal axis.

[0120] According to any one of the foregoing clauses, in the airfoil structure, the spring and damper system includes a spring configured to balance the rotational force applied by the plurality of dampers. The spring and the small damper are positioned on the same side of the longitudinal axis.

[0121] According to any one of the foregoing clauses, the airfoil structure further includes a leading edge and a trailing edge. The large damper is positioned at the front end of the leading edge, closer to the trailing edge than the trailing edge. The small damper is positioned at the rear end of the trailing edge, closer to the leading edge than the leading edge.

[0122] According to any one of the foregoing clauses, in the airfoil structure, the spring and damper system includes a spring configured to balance the rotational force applied by the plurality of dampers. The spring is positioned on the rear end.

[0123] A rotating airfoil assembly includes a plurality of airfoil structures according to any one of the preceding clauses, the plurality of airfoil structures being rotatable about a rotation axis of the rotating airfoil assembly.

[0124] According to the foregoing clauses, the rotating airfoil assembly, wherein the airfoil includes a leading edge, a trailing edge, a suction surface between the leading edge and the trailing edge, and a pressure surface between the leading edge and the trailing edge, the suction surface and the pressure surface being positioned on opposite sides of the airfoil such that when air flows over the suction surface and the pressure surface of the airfoil as the airfoil rotates about the axis of rotation, the airfoil generates lift, and the load applied to the airfoil is the generated lift.

[0125] An engine includes a rotating airfoil assembly according to any one of the preceding clauses and a torque generating system. The torque generating system is coupled to the rotating airfoil assembly and configured to rotate the rotating airfoil assembly about the rotation axis of the rotating airfoil assembly.

[0126] The engine according to any one of the foregoing clauses, wherein the engine is a ductless single-fan engine. The torque generation system is a turbine of a gas turbine engine. The rotating airfoil assembly is a fan. Each of the plurality of rotating airfoils is a fan blade.

[0127] An engine for an aircraft includes a rotating airfoil assembly, at least one actuator, a torque generation system, and a controller. The rotating airfoil assembly includes a rotation axis and a plurality of rotating airfoils configured to rotate about the rotation axis in a plane of rotation. The at least one actuator is operable to change the plane of rotation of the plurality of rotating airfoils. The torque generation system is coupled to the rotating airfoil assembly and configured to rotate the rotating airfoil assembly about the rotation axis of the rotating airfoil assembly. The controller is configured to determine that the aircraft has an angle of attack and operate the at least one actuator to change the plane of rotation of the plurality of rotating airfoils based on the angle of attack.

[0128] The engine according to any one of the foregoing clauses, wherein the controller is configured to receive an input indicating the pitch angle of the aircraft. The controller determines that the aircraft has an angle of attack based on the pitch angle of the aircraft.

[0129] The engine according to any one of the foregoing clauses, wherein the controller is communicatively coupled to a sensor to receive input from the sensor. The controller determines the angle of attack of the aircraft based on the pitch angle of the aircraft.

[0130] The engine according to any one of the foregoing clauses further includes the sensor.

[0131] The engine according to any one of the foregoing clauses, wherein the engine is a ductless single-fan engine. The torque generation system is a turbine of a gas turbine engine. The rotating airfoil assembly is a fan. Each of the plurality of rotating airfoils is a fan blade.

[0132] In any of the preceding clauses, the engine wherein the at least one actuator is a linear actuator.

[0133] In any of the preceding clauses, the engine wherein the at least one actuator is a hydraulic cylinder.

[0134] In any of the preceding clauses, the engine wherein the at least one actuator is a drive screw.

[0135] The engine according to any one of the foregoing clauses, wherein the at least one actuator alters the plane of rotation of the plurality of rotating airfoils by pivoting each rotating airfoil as the rotating airfoil rotates about the axis of rotation.

[0136] The engine according to any one of the foregoing clauses, wherein the rotating airfoil assembly includes a hub. Each rotating airfoil is pivotally connected to the hub via an arcuate groove. The at least one actuator is configured to change the plane of rotation of the plurality of rotating airfoils by moving each rotating airfoil within the arcuate groove.

[0137] The engine according to any one of the foregoing clauses, wherein the rotating airfoil assembly includes a hub. Each rotating airfoil is pivotally connected to the hub via a trunnion. Each rotating airfoil is fixed within the trunnion by a spherical bearing. The at least one actuator is configured to change the plane of rotation of the plurality of rotating airfoils by moving each rotating airfoil.

[0138] The engine according to any one of the foregoing clauses, wherein the at least one actuator alters the plane of rotation of the plurality of rotary airfoils by rotating the rotary airfoil assembly.

[0139] The engine according to any one of the foregoing clauses, wherein the torque generation system includes an output shaft. The rotating airfoil assembly includes a shaft coupled to the output shaft to receive torque from the output shaft and to rotate the rotating airfoil assembly.

[0140] In any of the preceding clauses, the shaft of the rotating airfoil assembly is supported by a spherical bearing.

[0141] In the engine according to any one of the foregoing clauses, the shaft of the rotating airfoil assembly is connected to the output shaft of the torque generation system via a differential gearbox. The differential gearbox is configured to allow the shaft of the rotating airfoil assembly to rotate relative to the output shaft.

[0142] In the engine according to any one of the foregoing clauses, the shaft of the rotating airfoil assembly is connected to the output shaft of the torque generation system via a constant velocity joint. The constant velocity joint is configured to allow the shaft of the rotating airfoil assembly to rotate relative to the output shaft.

[0143] The engine according to any one of the foregoing clauses, wherein the at least one actuator alters the plane of rotation of the plurality of rotating airfoils by rotating the rotating airfoil assembly together with the torque generating system.

[0144] The engine according to any one of the foregoing clauses further includes an engine support structure. The engine support structure is connected to the torque generating system via a plurality of mounting members. At least one of the plurality of mounting members is a movable mounting member. The at least one actuator is configured to move the movable mounting member to rotate the torque generating system.

[0145] The engine according to any one of the foregoing clauses, wherein the at least one actuator is configured to translate the movable mount.

[0146] In the engine according to any one of the foregoing clauses, the movable mount is pivotally connected to the engine support structure. The at least one actuator is configured to move the movable mount by rotating it about the pivot.

[0147] In the engine according to any one of the foregoing clauses, the at least one actuator is a cam. The cam is positioned on one side of the pivot. A spring is positioned on the other side of the pivot to balance the cam.

[0148] The engine according to any one of the foregoing clauses further includes an engine support structure. The engine support structure includes a front strut and a rear strut. The at least one actuator is configured to move the front strut relative to the rear strut to rotate the torque generating system.

[0149] The engine according to any one of the foregoing clauses, wherein the engine support structure is connected to the torque generating system via a plurality of mounting members. The plurality of mounting members are connected to the front strut.

[0150] The engine according to any one of the foregoing clauses, wherein the engine support structure is connected to the torque generating system via a front mount and a rear mount. The front mount is connected to the front strut. The rear mount is connected to the rear strut. The at least one actuator is configured to move the front strut away from the rear strut to rotate the torque generating system.

[0151] A mounting system for an aircraft engine includes an engine support structure, a plurality of mounting members, and at least one actuator. The plurality of mounting members are attached to the engine support structure to couple the aircraft engine to the engine support structure. At least one of the plurality of mounting members is a movable mounting member. The at least one actuator is operable to move the movable mounting member.

[0152] According to the mounting system described in the foregoing clauses, the engine support structure includes a channel. The movable mount is movable within the channel, and the channel guides the movement of the movable mount.

[0153] In the installation system according to any one of the foregoing clauses, the at least one actuator is configured to translate the movable mounting component.

[0154] The installation system according to any one of the foregoing clauses, wherein the movable mount is capable of translation in the vertical direction, and the at least one actuator is configured to cause the movable mount to translate in the vertical direction.

[0155] The installation system according to any one of the foregoing clauses, wherein the movable mount includes a platform. The at least one actuator is connected to the platform.

[0156] In the installation system according to any one of the foregoing clauses, the at least one actuator is a drive screw.

[0157] The installation system according to any one of the foregoing clauses, wherein the movable mounting component includes a platform clamp attached to the platform.

[0158] The installation system according to any one of the foregoing clauses further includes a plurality of the at least one actuator.

[0159] The installation system according to any one of the foregoing clauses, wherein the plurality of at least one actuator is located on the upper side of the platform.

[0160] The installation system according to any one of the foregoing clauses, wherein the plurality of at least one actuator is located on the underside of the platform.

[0161] The installation system according to any one of the foregoing clauses, wherein at least one of the plurality of at least one actuators is located on the upper side of the platform, and at least one of the plurality of at least one actuators is located on the lower side of the platform.

[0162] The mounting system according to any one of the foregoing clauses, wherein the movable mount includes a beam pivotally attached to the engine support structure via a pivot.

[0163] The mounting system according to any one of the foregoing clauses, wherein the beam includes a spherical single-ball bearing that enables mounting lugs to be attached thereto.

[0164] The installation system according to any one of the foregoing clauses, wherein the at least one actuator is connected to the beam to cause the beam to pivot about the pivot.

[0165] In the installation system according to any one of the foregoing clauses, the at least one actuator is a cam.

[0166] The mounting system according to any one of the foregoing clauses, wherein the cam is positioned on one side of the pivot and the spring is positioned on the other side of the pivot to balance the cam.

[0167] An engine for an aircraft includes a rotating airfoil assembly, a coupled torque generating system, and a mounting system according to any one of the preceding clauses. The rotating airfoil assembly includes a rotation axis and a plurality of rotating airfoils configured to rotate about the rotation axis in a plane of rotation. The torque generating system is coupled to the rotating airfoil assembly and configured to rotate the rotating airfoil assembly about the rotation axis of the rotating airfoil assembly. The torque generating system is connected to the engine support structure via the plurality of mounting elements.

[0168] The engine described in the foregoing clauses is a ductless single-fan engine, the torque generation system is a turbine of a gas turbine engine, and the rotating airfoil assembly is a fan, each of the plurality of rotating airfoils being a fan blade.

[0169] The engine according to any one of the foregoing clauses, wherein the at least one actuator is operable to change the plane of rotation of the plurality of rotating airfoils.

[0170] The engine according to any one of the foregoing clauses, wherein the plurality of mounting components includes a front mounting component and a rear mounting component, and one of the front mounting component or the rear mounting component is the movable mounting component.

[0171] The engine according to any one of the foregoing clauses further includes a controller configured to determine that the aircraft has an angle of attack, and to operate the at least one actuator to move the movable mount, and to change the plane of rotation of the plurality of rotating airfoils based on the angle of attack.

[0172] The engine according to any one of the foregoing clauses, wherein the controller is configured to receive an input indicating the pitch angle of the aircraft, the controller determining, based on the pitch angle of the aircraft, that the aircraft has an angle of attack.

[0173] An installation system for an aircraft engine includes an engine support structure, a plurality of mounting members, and at least one actuator. The engine support structure includes a front strut and a rear strut. The plurality of mounting members are attached to the engine support structure to couple the aircraft engine to the engine support structure. The at least one actuator is operable to cause relative movement of one of the front struts or the rear strut relative to the other of the front struts or the rear strut.

[0174] According to the installation system described in the foregoing clauses, the front strut is pivotable relative to the rear strut.

[0175] According to any one of the preceding clauses, in the installation system, one of the plurality of mounting components is a front mounting component connected to the front strut, and one of the plurality of mounting components is a rear mounting component connected to the rear strut.

[0176] The installation system according to any one of the foregoing clauses, wherein the at least one actuator is movable between a retracted position and an extended position, and moving the at least one actuator from the retracted position to the extended position causes the front strut to move away from the rear strut.

[0177] An installation system according to any one of the foregoing clauses, wherein moving the at least one actuator from the retracted position to the extended position causes the front strut to move downward from the rear strut.

[0178] The installation system according to any one of the foregoing clauses, wherein the rear strut includes a bending groove, and the front strut includes an engaging strut that engages with the bending groove, and guides rotation of the front strut as the at least one actuator moves between the retracted position and the extended position.

[0179] The installation system according to any one of the foregoing clauses, wherein the plurality of mounting components are connected to the front pillar.

[0180] The installation system according to any one of the foregoing clauses further includes at least one pivot that pivotally connects the front strut to the rear strut.

[0181] The installation system according to any one of the foregoing clauses, wherein the at least one actuator is positioned relative to the at least one pivot such that extending or retracting the at least one actuator causes the front strut to pivot about the at least one pivot.

[0182] The installation system according to any one of the foregoing clauses, wherein the at least one actuator is connected to the upper portion of the respective front strut and the rear strut, and the at least one pivot is located on the lower portion of the respective front strut and the rear strut.

[0183] An engine for an aircraft includes a rotating airfoil assembly, a torque generation system, and a mounting system according to any one of the preceding clauses. The rotating airfoil assembly includes a rotation axis and a plurality of rotating airfoils configured to rotate about the rotation axis in a plane of rotation. The torque generation system is coupled to the rotating airfoil assembly and configured to rotate the rotating airfoil assembly about the rotation axis. The torque generation system is connected to the engine support structure via the plurality of mounting elements.

[0184] According to the engine described in the foregoing clauses, the at least one actuator is operable to change the plane of rotation of the plurality of rotating airfoils.

[0185] The engine according to any one of the foregoing clauses, wherein the engine is a ductless single-fan engine, the torque generation system is a turbine of a gas turbine engine, and the rotating airfoil assembly is a fan, each of the plurality of rotating airfoils being a fan blade.

[0186] The engine according to any one of the foregoing clauses further includes a controller configured to determine that the aircraft has an angle of attack and to operate the at least one actuator to move one of the front strut or the rear strut relative to each other, and to change the plane of rotation of the plurality of rotating airfoils based on the angle of attack.

[0187] The engine according to any one of the foregoing clauses, wherein the controller is configured to receive an input indicating the pitch angle of the aircraft, the controller determining, based on the pitch angle of the aircraft, that the aircraft has an angle of attack.

[0188] An engine for an aircraft includes a torque generation system, a rotating airfoil assembly, and at least one actuator operable to change the pitch angle of the rotating airfoil assembly. The torque generation system includes an output shaft. The torque generation system outputs torque via the output shaft. The rotating airfoil assembly includes a rotation axis and a plurality of rotating airfoils configured to rotate about the rotation axis in a plane of rotation. The rotating airfoil assembly includes an input shaft coupled to the output shaft to receive torque from the output shaft and to rotate the rotating airfoil assembly. The input shaft is coupled to the output shaft via a pivotable coupling to allow rotation of the input shaft, thereby changing the pitch angle relative to the output shaft.

[0189] According to the engine described in the foregoing clauses, the input shaft of the rotating airfoil assembly is supported by a spherical bearing.

[0190] In any of the preceding clauses, the input shaft of the rotating airfoil assembly is supported by a cylindrical bearing.

[0191] In any of the preceding clauses, the pivotable coupling is a constant velocity joint.

[0192] In any of the preceding clauses, the pivotable coupling in the engine is a differential gearbox.

[0193] The engine according to any one of the foregoing clauses, wherein the differential gearbox includes an input gear connected to the output shaft of the torque generation system, an output gear connected to the rotating airfoil assembly, and a pair of drive gears. The input gear and the output gear each engage with the pair of drive gears to transmit the torque from the input gear to the output gear.

[0194] In any of the preceding clauses, the transmission gears are positioned opposite each other on opposite sides of the input gear and the output gear.

[0195] The engine according to any one of the foregoing clauses, wherein the torque generating system includes a housing, and the rotating airfoil assembly is pivotally connected to the housing.

[0196] The engine according to any one of the foregoing clauses, wherein the rotating airfoil assembly is pivotally connected to the housing via a ball joint.

[0197] The engine according to any one of the foregoing clauses, wherein the engine is a ductless single-fan engine, the torque generation system is a turbine of a gas turbine engine, and the rotating airfoil assembly is a fan, each of the plurality of rotating airfoils being a fan blade.

[0198] The engine according to any one of the foregoing clauses further includes a controller configured to determine that the aircraft has an angle of attack and to operate the at least one actuator to move the rotating airfoil assembly.

[0199] The engine according to any one of the foregoing clauses, wherein the controller is configured to receive an input indicating the pitch angle of the aircraft, the controller determining, based on the pitch angle of the aircraft, that the aircraft has an angle of attack.

[0200] An engine for an aircraft includes a rotating airfoil assembly, at least one actuator, and a torque generating system coupled to the rotating airfoil assembly. The rotating airfoil assembly includes a rotation axis and a plurality of rotating airfoils configured to rotate about the rotation axis in a plane of rotation. The at least one actuator is operable to change the plane of rotation of the plurality of rotating airfoils by pivoting each rotating airfoil as it rotates about the rotation axis. The torque generating system is configured to rotate the rotating airfoil assembly about the rotation axis of the rotating airfoil assembly.

[0201] The engine, as described in the foregoing clauses, further includes a plurality of the at least one actuator. One of the plurality of actuators is connected to a corresponding one of the plurality of rotating airfoils in front of the corresponding rotating airfoil, and another of the plurality of actuators is connected to the corresponding rotating airfoil behind the corresponding rotating airfoil to change the pitch angle of the corresponding rotating airfoil.

[0202] The engine according to any one of the foregoing clauses, wherein the engine is a ductless single-fan engine, the torque generation system is a turbine of a gas turbine engine, and the rotating airfoil assembly is a fan, each of the plurality of rotating airfoils being a fan blade.

[0203] The engine according to any one of the foregoing clauses further includes a plurality of the at least one actuator, at least one of the plurality of actuators being connected to a corresponding one of the plurality of rotating airfoils to change the pitch angle of the corresponding rotating airfoil.

[0204] The engine according to any one of the foregoing clauses, wherein the rotating airfoil assembly includes a hub, each rotating airfoil being pivotally connected to the hub via a pivotable connection that allows the rotating airfoil to change its pitch angle.

[0205] The engine according to any one of the foregoing clauses, wherein each rotating airfoil is pivotally connected to the hub via an arcuate groove.

[0206] In any of the preceding clauses, the arcuate groove is oriented in the forward and rearward directions of the engine.

[0207] The engine according to any one of the foregoing clauses further includes a controller configured to determine that the aircraft has an angle of attack and to operate the at least one actuator to pivot each of the rotating airfoils as the rotating airfoils rotate about the axis of rotation.

[0208] The engine according to any one of the foregoing clauses, wherein the controller is configured to receive an input indicating the pitch angle of the aircraft, the controller determining, based on the pitch angle of the aircraft, that the aircraft has an angle of attack.

[0209] The engine according to any one of the foregoing clauses, wherein the controller is configured to operate the at least one actuator to cause each rotating airfoil to move independently.

[0210] The engine according to any one of the foregoing clauses, wherein the rotating airfoil assembly includes a hub. Each rotating airfoil is pivotally connected to the hub via an arcuate groove. The arcuate groove is oriented in the forward and rearward directions of the engine. The controller is configured to operate the at least one actuator to move each rotating airfoil independently between a front portion and a rear portion of the arcuate groove.

[0211] The engine according to any one of the foregoing clauses, wherein the controller is configured to position the rotating airfoil in the front portion of the arcuate recess when the rotating airfoil is located at the twelve o'clock position of the rotating airfoil assembly. The controller is configured to position the rotating airfoil in the rear portion of the arcuate recess when the rotating airfoil is located at the six o'clock position of the rotating airfoil assembly.

[0212] The engine according to any one of the foregoing clauses, wherein the rotating airfoil assembly includes a hub. Each rotating airfoil is pivotally connected to the hub via a trunnion, and each rotating airfoil is fixed within the trunnion by a spherical bearing. The at least one actuator is configured to change the plane of rotation of the plurality of rotating airfoils by moving each rotating airfoil.

[0213] The engine according to any one of the foregoing clauses, wherein the rotating airfoil includes a root having a spherical portion, and the trunnion fixes the spherical portion.

[0214] In the engine according to any one of the foregoing clauses, the trunnion includes a groove, and the root includes an inner portion extending below the ball and entering the groove.

[0215] An engine according to any one of the foregoing clauses, wherein the size of the inner portion relative to the slot is determined to restrict movement in one direction, but has a clearance to allow movement in another direction.

[0216] An aircraft comprising an engine according to any one of the foregoing provisions.

[0217] The aircraft described in the foregoing clauses further includes a fuselage and wings attached to the fuselage.

[0218] An aircraft according to any one of the foregoing clauses, wherein the engine is mounted to the wing.

[0219] The aircraft according to any one of the foregoing clauses, wherein the engine is mounted to the wing in an underwing configuration via a pylon.

[0220] The aircraft according to any one of the foregoing clauses, wherein the pylon includes an engine support structure according to any one of the foregoing clauses.

[0221] The aircraft according to any one of the foregoing clauses further includes a flight controller, wherein the controller is communicatively coupled to the flight controller to receive input from the flight controller.

[0222] An aircraft according to any one of the foregoing clauses, wherein the input is one of the aircraft's angle of attack or the aircraft's pitch angle.

[0223] The aircraft according to any one of the foregoing clauses, wherein the aircraft includes the sensor.

[0224] While the foregoing description is directed toward preferred embodiments, other variations and modifications will be apparent to those skilled in the art and can be made without departing from the spirit or scope of this disclosure. Furthermore, features described in connection with one embodiment may be used in conjunction with other embodiments, even if not explicitly stated above.

Claims

1. An airfoil structure, characterized in that, include: An airfoil having a longitudinal axis; and A spring and damper system connected to the airfoil to rotate the airfoil about the longitudinal axis, thereby changing the pitch angle of the airfoil in response to a load applied to the airfoil. The spring and damper system includes a plurality of dampers operably engaged with the airfoil and arranged to apply a rotational force to the airfoil. Each of the plurality of dampers is a hydraulic damper and is fluidly connected to each other via a fluid conduit facilitating the flow of hydraulic fluid between the plurality of dampers.

2. The airfoil structure according to claim 1, characterized in that, The spring and damper system further includes a spring operably engaged with the airfoil and arranged to balance the rotational force applied by the plurality of dampers.

3. The airfoil structure according to claim 2, characterized in that, The airfoil further includes a root, and the plurality of dampers and the spring are connected to the root to apply the rotational force to the root.

4. The airfoil structure according to claim 3, characterized in that, The device further includes a trunnion, the trunnion including a bearing, wherein the root includes a ball portion fixed in the trunnion by the bearing to allow the ball portion to rotate about the longitudinal axis.

5. The airfoil structure according to claim 4, characterized in that, The root portion includes an inner portion extending below the ball portion and into a groove formed in the trunnion, wherein the plurality of dampers and the spring are connected to the inner portion of the root portion.

6. The airfoil structure according to claim 1, characterized in that, Each of the plurality of dampers includes a piston, and The plurality of dampers includes a large damper and a small damper, wherein the piston of the small damper has a smaller surface area than the piston of the large damper.

7. The airfoil structure according to claim 6, characterized in that, The large damper and the small damper are positioned on opposite sides of the longitudinal axis.

8. A rotating airfoil component assembly, characterized in that, It includes multiple airfoil structures according to claim 1, the multiple airfoil structures being rotatable about the rotation axis of the rotating airfoil assembly.

9. An engine, characterized in that, include: A rotating airfoil assembly, the rotating airfoil assembly comprising a plurality of airfoil structures rotatable about a rotation axis of the rotating airfoil assembly, each of the plurality of airfoil structures comprising: Airfoil, the airfoil having a longitudinal axis; and A spring and damper system connected to the airfoil to allow rotation of the airfoil about the longitudinal axis, thereby changing the pitch angle of the airfoil in response to a load applied to the airfoil. Each airfoil of the plurality of airfoil structures is rotatable about the longitudinal axis via the spring and damper system, independent of the airfoil elements of the other airfoil structures of the plurality of airfoil structures; and A torque generating system is coupled to the rotating airfoil assembly and arranged to rotate the rotating airfoil assembly about its axis of rotation.

10. The engine according to claim 9, characterized in that, The engine is a ductless single-fan engine, the torque generation system is a gas turbine engine turbine, the rotating airfoil assembly is a fan, and each airfoil is a fan blade.

11. An airfoil structure, characterized in that, include: An airfoil having a longitudinal axis; and A spring and damper system, connected to the airfoil to rotate the airfoil about the longitudinal axis, thereby changing the pitch angle of the airfoil in response to a load applied to the airfoil, the spring and damper system comprising a plurality of dampers operably engaged with the airfoil and arranged to apply a rotational force to the airfoil. Each of the plurality of dampers is fluidly connected to each other and includes a piston. The plurality of dampers includes a large damper and a small damper, wherein the piston of the small damper has a smaller surface area than the piston of the large damper.

12. The airfoil structure according to claim 11, characterized in that, The smaller damper applies a smaller pressure load to the airfoil than the larger damper.

13. The airfoil structure according to claim 11, characterized in that, The large damper and the small damper are positioned on opposite sides of the longitudinal axis.

14. The airfoil structure according to claim 13, characterized in that, The spring and damper system includes a spring operably engaged with the airfoil and arranged to balance the rotational force applied by the plurality of dampers, the spring and the small damper being positioned on the same side of the longitudinal axis.

15. The airfoil structure according to claim 13, characterized in that, The airfoil further includes a leading edge and a trailing edge, and The large damper is positioned at the front end, which is closer to the leading edge than the trailing edge, and the small damper is positioned at the rear end, which is closer to the trailing edge than the leading edge.

16. The airfoil structure according to claim 15, characterized in that, The spring and damper system includes a spring operably engaged with the airfoil and arranged to balance rotational forces applied by the plurality of dampers, the spring being positioned on the rear end.

17. The airfoil structure according to claim 11, characterized in that, The airfoil further includes a leading edge, a trailing edge, and a chord extending from the leading edge to the trailing edge, wherein the large damper and the small damper are positioned on opposite sides of the chord.

18. The airfoil structure according to claim 17, characterized in that, The spring and damper system includes a spring operably engaged with the airfoil and arranged to balance the rotational forces applied by the plurality of dampers, the spring and the large damper being positioned on the same side of the chord.

19. The airfoil structure according to claim 17, characterized in that, The airfoil further includes a pressure side and a suction side, and The large damper is located on the pressure side, and the small damper is located on the suction side.

20. The airfoil structure according to claim 19, characterized in that, The spring and damper system includes a spring operably engaged with the airfoil and arranged to balance the rotational force applied by the plurality of dampers, the spring being positioned on the pressure side.

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