Thrust vectoring propeller

Abstract

A two-dimensional gimbaled propeller produces a vector thrust. A directional propeller produces a two-dimensional propulsion thrust vector without producing adverse moments or translational forces. By directing the vector through the aerodynamic center of the propeller, the forces required to control the propulsion vector are minimized, decoupled from the power source that is delivered to the propeller through a drive shaft with a fixed orientation.

Description

[0001] Related applications This application relates to and claims priority to U.S. provisional patent applications filed November 9, 2023, No. 63 / 597,429, February 29, 2024, No. 63 / 559,318, May 3, 2024, No. 63 / 642,309, and June 22, 2024, No. 63 / 663,089, and U.S. non-provisional patent application filed August 8, 2024, No. 17 / 797,777, all of which are hereby incorporated herein by reference for all purposes and are deemed to be fully set forth herein. Technical Field

[0002] The embodiments of the present invention generally relate to ducted propellers, and more specifically to thrust vectoring ducted propellers. Background Technology

[0003] Thrust vectoring, or thrust vector control, refers to the ability to control an aircraft's attitude or angular velocity by manipulating the direction and magnitude of thruster thrust. Thrust vectoring is well known to enhance and / or replace control systems, thereby improving the performance and efficiency of aircraft utilizing this technology.

[0004] The development of thrust vectoring reaction engines in the 1930s spurred the development of rocket technology and rocket flight. Continued advancements in thrust vectoring and control technologies have recently enabled rockets to return to their launch sites and land tail-to-tail. Thrust vectoring in turbine engines gives modern fighter jets extremely high maneuverability and the ability to fly at high angles of attack after stall. However, turbine engines are inefficient at low altitudes and speeds, thus necessitating thrust vectoring generated by propellers.

[0005] Thrust vectoring for propeller-driven aircraft remains a challenge. Propeller-based thrust vectoring primarily relies on: 1) tilting the rotor plane through cyclically varying the blade pitch, 2) deflecting the outlet airflow, or 3) tilting the engine and propeller as a unit to adjust the direction of the thrust vector. None of these methods have yielded the revolutionary performance improvements seen in rockets and turbine aircraft.

[0006] Collectively variable pitch blades are most commonly used in open rotor systems where the blades are long enough to justify the increased complexity of the swashplate and the inertia of the pitch bearing at the hub. Collectively variable blades generate a consistent downward thrust as the aircraft moves forward (or backward or laterally) by changing their pitch in each cycle or rotation. The terms "rotor" and "propeller" are generally used interchangeably. For the purposes of this invention, the term "rotor" refers to an assembly with unshielded blades and a collective, periodically variable pitch similar to that of a conventional helicopter rotor. The term "propeller" as used herein can be shrouded or unshielded, with blades of fixed pitch or collectively adjustable pitch. Because of the rotor's length, its rotational speed is much lower than that of a propeller, to keep its tip speed below the speed of sound.

[0007] Rotor systems controlled by tilting rotor discs require a joint at the rotor hub to allow tilting relative to the mast. Various types of joints have been developed to accommodate this tilting, including constant velocity universal joints. Because these joints do not transmit axial loads, a complex arrangement is required to transfer thrust loads to the mast.

[0008] Generally, periodic control of pitch is not suitable for ducted propellers. The centrifugal force of a rotating propeller is much greater than that of a slower-rotating rotor. The added complexity and weight of pitch bearings and swashplates typically require blades that are long enough to benefit from the additional structure and maintenance. This is generally not possible with the limited diameter and high rotational speed of ducted propellers.

[0009] There are various forms of aerodynamic manipulation of propeller exit flow. These include peripheral control jets (see U.S. Patent 8,413,932, 2013, DeRoche), deflectors (see U.S. Patent 10,538,311, 2020, Halcom et al.), and sidewall treatments (see U.S. Patent 5,277,381, 1994, Piasecki). While these methods are effective for their application, the control forces that can be generated by slipstream manipulation are limited. These forces represent only a fraction of the total available thrust, and even these forces vary with external conditions.

[0010] Tilt the propeller and its engine as a whole to redirect thrust, which is common in tiltrotor aircraft for the transition between vertical and horizontal flight, but not so much for control. With the recent introduction of distributed electric propulsion, the application of tilt motor-propeller pairs in aircraft control is being explored more extensively.

[0011] While single-axis tilting of a motor-propeller pair is mechanically simple, dual-axis tilting can be quite complex (see U.S. Patent 10,737,778, 2020, Oldroyd et al.). One problem with motor-propeller tilting is that the position of the tilt axis leads to unbalanced control loads and unfavorable control torques. Furthermore, in this configuration, control coupling is exacerbated by the high inertia and gyroscopic precession of the motor's rotating core, thus limiting its use primarily to smaller unmanned aerial vehicles or slower-rotating rotors.

[0012] What is lacking is the ability to use propellers for thrust vectoring. More specifically, a thrust vectoring ducted propeller capable of two-dimensional thrust control is needed. One or more embodiments of the present invention address these and other shortcomings of the prior art.

[0013] Additional advantages and novel features of the invention will be set forth in part in the description which follows, will become apparent to those skilled in the art upon review of the following specification, or may be learned by practicing the invention. The advantages of the invention may be realized and obtained by means, combinations, compositions, and methods particularly pointed out in the appended claims. Summary of the Invention

[0014] This document discloses and describes a ducted propeller configured to generate and control two-dimensional vector thrust. According to one embodiment of the invention, the ducted propeller generates a thrust vector without producing adverse torque or translational forces. By pivoting at the propeller's thrust plane and thrust center, the forces required to control the thrust vector are minimized. Furthermore, the invention allows the engine (or motor) and drive shaft to be fixed to the aircraft fuselage while the thrust vector is independently guided.

[0015] One embodiment of the invention isolates the engine and powertrain from the propulsion and aerodynamic loads generated by the ducted propeller. The ducted propeller configuration described herein provides discrete load paths to the main aircraft, reducing wear on the powertrain, and is simpler to integrate compared to conventional propellers and rotors, where torque, thrust, and flight loads are borne by the mast or drive shaft.

[0016] A propeller assembly, a constant velocity (CV) gimbal, and an outer strut constitute a directional thrust propeller system. The propeller assembly includes an aerodynamic center with a pivot interface and a propeller pivot shaft extending through the aerodynamic center of the propeller assembly. The propeller assembly also includes propeller blades, each blade consisting of a blade root, a blade tip, a blade body, and a trailing edge assembly. In one embodiment, the propeller assembly is mounted within a propeller guide. The constant velocity (CV) gimbal is located within the aerodynamic center of the propeller assembly and attached to a drive shaft located within the aerodynamic center of the propeller assembly. Another embodiment of the invention includes a gimbal assembly having a gimbal pivot interface and a propeller gimbal pivot shaft extending through the aerodynamic center. In such an embodiment, the propeller assembly is independently directional in two dimensions. In both cases, the outer strut is located between the propeller assembly and the pivot interface and is configured to transfer loads generated by the propeller assembly to the pivot interface. In one embodiment, the CV gimbal is a tripod-type gimbal.

[0017] Another embodiment of the invention includes a main bearing located between the propeller assembly and the outer strut. The main bearing transmits the load generated by the propeller assembly to the outer strut. The outer strut may include movable blades that counteract gyro precession via a gyro precession controller. Between the propeller assembly and the drive shaft is an inner strut designed to transmit the radial load generated by the propeller assembly. Between the inner strut and the propeller assembly is an auxiliary bearing.

[0018] The features and advantages described in this disclosure and the following detailed description are not exhaustive. Many additional features and advantages will be apparent to those skilled in the art upon review of the accompanying drawings, specification, and claims. Furthermore, it should be noted that the language used in the specification has been chosen primarily for readability and edutainment purposes and may not have been selected to define or limit the subject matter of the invention; such subject matter should be determined with reference to the claims. Attached Figure Description

[0019] The features and objects of the present invention and their implementation will become more apparent from the following description of one or more embodiments in conjunction with the accompanying drawings, and the invention itself will be best understood.

[0020] Figure 1 This is an isometric view of a thrust vectoring duct propeller according to an embodiment of the present invention.

[0021] Figure 2A and Figure 2B This is a free-body force diagram of a thrust vector ducted propeller according to an embodiment of the present invention.

[0022] Figure 3An exploded view of a thrust vectoring duct propeller according to an embodiment of the present invention is shown.

[0023] Figure 4 This is an inner end view of a thrust vectoring duct propeller according to an embodiment of the present invention.

[0024] Figure 5 yes Figure 4 A cross-sectional view of a thrust vector ducted propeller.

[0025] Figure 6 This is a top perspective view of a propeller including a thrust vectoring duct at the trailing edge of the propeller blades, according to an embodiment of the present invention.

[0026] Figure 7A shows a cross-sectional view of a thrust vectoring duct propeller according to an embodiment of the present invention, including the central hub of the propeller assembly.

[0027] Figure 7B and Figure 7C This is an enlarged view of the central hub of the propeller assembly in Figure 7A.

[0028] Figure 8 This is a top view of a plurality of propeller blades in a propeller assembly of a thrust vectoring duct propeller according to an embodiment of the present invention.

[0029] Figure 9 This is a cross-sectional view of a thrust vectoring duct propeller with a hinged trailing edge according to an embodiment of the present invention.

[0030] Figure 10 This is a detailed side view of a thrust vectoring ducted propeller according to an embodiment of the present invention, including a propeller blade trailing edge collective changing mechanism and a CV universal joint.

[0031] Figures 11A to 11I A perspective view of a thrust vectoring ducted propeller under various directional thrust configurations is provided according to an embodiment of the present invention.

[0032] Figure 12 This is a perspective view of a shieldless (free tip) thrust vectoring propeller according to an embodiment of the present invention.

[0033] Figure 13A and Figure 13B A gyro precession control mechanism for a thrust vector duct propeller on the pitch axis is shown according to an embodiment of the present invention.

[0034] Figure 14A and Figure 14B A gyro precession control mechanism for a thrust vector duct propeller on the yaw axis is shown according to an embodiment of the present invention.

[0035] Figure 15 A flowchart of a gyro precession control method for a thrust vector ducted propeller according to an embodiment of the present invention is presented.

[0036] Figure 16 The main aircraft interface of a thrust vectoring ducted propeller according to an embodiment of the present invention is shown.

[0037] Figure 17 This is a cross-sectional view of the main aircraft interface of a thrust vectoring duct propeller according to an embodiment of the present invention.

[0038] Figure 18 A reconnaissance unmanned aerial vehicle (UAV) with a dual-spike structure integrated with a thrust vectoring duct propeller is shown according to an embodiment of the present invention.

[0039] Figure 19 A blended wing-body flying wing aircraft integrating a thrust vectoring duct propeller is shown according to an embodiment of the present invention.

[0040] Figure 20 A tail-sitting aircraft with an integrated thrust vectoring duct propeller is shown according to an embodiment of the present invention.

[0041] Figure 21 A rotorcraft with an integrated thrust vectoring duct propeller is presented according to an embodiment of the present invention.

[0042] Figure 22 A conventional pull-type general aviation aircraft with an integrated thrust vectoring duct propeller is shown according to an embodiment of the present invention.

[0043] Figure 23 A propulsion-type general aviation aircraft with an integrated thrust vectoring duct propeller is shown according to an embodiment of the present invention.

[0044] The accompanying drawings are for illustrative purposes only and depict embodiments of the invention. Throughout the drawings, the same numbers refer to the same elements. In the drawings, the dimensions of certain lines, layers, components, elements, or features may be enlarged for clarity. Those skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods shown herein may be employed without departing from the principles of the invention as described herein. Detailed Implementation

[0045] A fully gimbaled ducted propeller pivots around an aerodynamic center and directs its thrust through this center. In one embodiment of the invention, a drive shaft is connected to a constant velocity gimbal at the aerodynamic center of the propeller assembly. The load (thrust) generated by the propeller assembly is transmitted to the propeller duct via one or more struts, and then to the aircraft on which the assembly is mounted. The invention can be configured as a pusher or puller propeller, and can be a fixed-pitch propeller (where thrust can be varied by rotational speed) or a constant-speed configuration (where thrust is varied by modifying the pitch of the propeller assembly). Gyroscopic precession is compensated for by multiple guide vanes and a precession controller.

[0046] This invention aims to provide propeller propulsion for aerial or seaplane vehicles. For clarity, the aeronautical version will be described in detail, while it should be understood that the innovations presented herein also apply to both. For the sake of brevity in the following description, the "thrust vectoring ducted propeller" invention and its embodiments described herein will be simply referred to as the "propeller".

[0047] Embodiments of the present invention are described in detail below with reference to the accompanying drawings. While the invention has been described and illustrated with a degree of specificity, it should be understood that this disclosure is by way of example only, and those skilled in the art can make various changes to the combination and arrangement of parts without departing from the spirit and scope of the invention.

[0048] The following description, with reference to the accompanying drawings, is intended to aid in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to aid understanding, but these should be considered exemplary only. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. Furthermore, for clarity and brevity, descriptions of well-known functions and structures have been omitted.

[0049] The terms and words used in the following description and claims are not limited to their documentary meaning, but are used by the inventors only to provide a clear and consistent understanding of the invention. Therefore, it will be apparent to those skilled in the art that the following description of exemplary embodiments of the invention is provided for illustrative purposes only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

[0050] The term "approximately" means that the feature, parameter, or value does not need to be precisely achieved, but may have some deviations or variations, such as tolerances, measurement errors, measurement accuracy limitations, and other factors known to those skilled in the art, which may occur in a quantity that does not impede the effect that the feature is intended to provide.

[0051] The terminology used herein is for the purpose of describing embodiments only and is not intended to limit the invention. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” as used herein also include the plural forms. Thus, for example, a reference to “a component surface” also includes a reference to one or more such surfaces.

[0052] As used herein, any reference to "an embodiment" or "an embodiment" means that a particular element, feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. The phrase "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment.

[0053] As used herein, the terms “comprising,” “including,” “containing,” “containing,” “having,” “having,” or any other variation thereof are intended to cover non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such a process, method, article, or apparatus. Furthermore, unless expressly stated otherwise, “or” means inclusive “or,” not exclusive “or.” For example, condition A or B is satisfied by any of the following: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); and both A and B are true (or exist).

[0054] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms defined in common dictionaries should be interpreted as having the same meaning as they have in the context of the specification and the relevant field, and should not be interpreted in an idealized or overly formal sense unless explicitly defined herein. For the sake of brevity and / or clarity, well-known functions or structures may not be described in detail.

[0055] It should also be understood that when an element is referred to as being "on," "attached," "connected," "coupled," "contacting," "mounted," etc., to another element, it may be directly on, attached to, connected to, coupled to, or in contact with the other element, or there may be intermediate elements present. Conversely, when an element is referred to, for example, as being "directly on," "directly attached," "directly connected," "directly coupled to," or "directly in contact with" another element, there are no intermediate elements. Those skilled in the art will also understand that references to structures or features arranged "adjacent" to another feature may have portions that overlap with or are located below the adjacent feature.

[0056] Spatial relative terms, such as “below,” “bottom,” “lower,” “above,” “higher,” etc., are used herein to conveniently describe the relationship of one element or feature to another element(s), as illustrated in the accompanying figures. It should be understood that spatial relative terms are intended to cover different orientations of the device in use or operation, as well as the orientations shown in the accompanying figures. For example, if the device in the accompanying figures is flipped, an element described as “below” or “under” other elements or features would be oriented as “above” other elements or features. Thus, the exemplary term “below” can cover both “above” and “below” orientations. The device may be oriented in other ways (rotated 90 degrees or other orientations), and the spatial relative descriptive terms used herein should be interpreted accordingly. Similarly, the terms “up,” “down,” “vertical,” “horizontal,” etc., are used herein for illustrative purposes only unless otherwise specified.

[0057] The description includes flowcharts illustrating examples of methods that can be used to guide and control thrust generated by a fully gimbaled ducted propeller. In the following description, it should be understood that each block in the flowchart, as well as combinations of blocks in the flowchart, can be implemented by computer program instructions. These computer program instructions can be loaded onto a computer or other programmable device to produce a machine such that the instructions, which execute on the computer or other programmable device, create a mechanism for implementing the flowchart. Figure 1 The computer program instructions may also be stored in a computer-readable storage medium that can instruct a computer or other programmable device to operate in a particular manner, causing the instructions stored in the computer-readable storage medium to produce an implementation flow. Figure 1 Articles of manufacture of instruction means that specify functions in one or more boxes. Computer program instructions may also be loaded onto a computer or other programmable means to cause a series of operational steps to be performed on the computer or other programmable means to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable means, provide an implementation flow. Figure 1 The steps that specify the function in one or more boxes.

[0058] Therefore, the blocks of a flowchart support combinations of means for performing a specified function and combinations of steps for performing a specified function. It should also be understood that each block of a flowchart, and combinations of blocks in a flowchart, can be implemented by a dedicated hardware computer system or a combination of dedicated hardware and computer instructions that performs the specified function or step.

[0059] Certain portions of this specification are presented as algorithms or symbolic representations of operations on data bits or binary digital signals stored in machine memory (e.g., computer memory). These algorithms or symbolic representations are technical examples used by those skilled in the art of data processing to communicate the substance of their work to others skilled in the art. As used herein, an "algorithm" is a self-consistent sequence of operations or similar processing that leads to a desired result. In this context, algorithms and operations involve the manipulation of information elements. Typically, but not necessarily, such elements may take the form of electrical, magnetic, or optical signals that can be stored, accessed, transmitted, combined, compared, or otherwise manipulated by a machine. Sometimes, primarily for common reasons, it is convenient to use terms such as "data," "content," "bit," "value," "element," "symbol," "character," "item," "number," "digit," "word," etc., to refer to such signals. However, these specific terms are merely convenient labels and should be associated with the appropriate information element.

[0060] Unless otherwise specified, the use of terms such as “processing,” “computing,” “operation,” “determining,” “presenting,” and “displaying” in this document can refer to the actions or processes of a machine (e.g., a computer) that manipulate or transform data represented as physical (e.g., electronic, magnetic, or optical) quantities in one or more memories (e.g., volatile memory, non-volatile memory, or combinations thereof), registers, or other machine components that receive, store, transmit, or display information.

[0061] Upon reading this disclosure, those skilled in the art will recognize, through the principles disclosed herein, numerous alternative structural and functional designs for systems and processes used in universal joint ducted propellers. Therefore, while embodiments and applications have been illustrated and described, it should be understood that the disclosed embodiments are not limited to the precise constructions and components disclosed herein. Various modifications, alterations, and variations that will be apparent to those skilled in the art may be made to the arrangement, operation, and details of the methods and apparatus disclosed herein without departing from the spirit and scope defined in the appended claims.

[0062] Those skilled in the art will also understand that the present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. Similarly, the naming and division of modules, managers, functions, systems, engines, layers, features, attributes, methods, and other aspects are not mandatory or essential, and mechanisms for implementing the present invention or its features may have different names, divisions, and / or formats. Furthermore, as will be apparent to those skilled in the art, the modules, managers, functions, systems, engines, layers, features, attributes, methods, and other aspects of the present invention can be implemented as software, hardware, firmware, or any combination thereof. Of course, as long as a component of the present invention is implemented as software, that component can be implemented as a script, a standalone program, part of a larger program, multiple standalone scripts and / or programs, a static or dynamic link library, a kernel-loadable module, a device driver, and / or every and any other manner now or in the future known to those skilled in the art of computer programming. Moreover, the present invention is by no means limited to implementation in any particular programming language or any particular operating system or environment. Therefore, the disclosure of the present invention is intended to illustrate rather than limit the scope of the invention, the scope of which is set forth in the following claims.

[0063] In a preferred embodiment, one or more portions of the invention may be implemented in software. The software programming code embodying the invention is typically accessed by a microprocessor from some type of long-term persistent storage medium, such as a flash drive or hard disk drive. The software programming code can be embodied on any of the various known media used in data processing systems, such as floppy disks, hard disk drives, CD-ROMs, etc. The code can be distributed on such media or distributed from the memory or storage device of a computer system to other computer systems for use by such other systems via some type of network. Alternatively, the programming code can be embodied in the memory of a device and accessed by a microprocessor using an internal bus. Techniques and methods for embodying software programming code in memory, physical media, and / or distributing software code over a network are well known and will not be discussed further here.

[0064] Generally, program modules include routines, programs, objects, components, data structures, etc., that perform tasks or implement abstract data types. Furthermore, those skilled in the art will understand that this invention can be implemented using other computer system configurations, including handheld devices, multiprocessor systems, microprocessor-based or programmable consumer electronics, network PCs, microcomputers, mainframe computers, etc. This invention can also be implemented in a distributed computing environment, where tasks are performed by remote processing devices connected via a communication network. In a distributed computing environment, program modules can reside in both local and remote storage devices.

[0065] An exemplary system for implementing the present invention includes a general-purpose computing device, such as a conventional personal computer, personal communication device, etc., comprising a processing unit, system memory, and a system bus coupling various system components, including the system memory, to the processing unit. The system bus can be any of several types of bus architectures, including a memory bus or memory controller, a peripheral bus, and a local bus using various bus architectures. The system memory typically includes read-only memory (ROM) and random access memory (RAM). A basic input / output system (BIOS) containing basic routines is stored in the ROM, which facilitates the transfer of information between components within the personal computer, for example, during startup. The personal computer may also include a hard disk drive for reading from and writing to a hard disk, and a disk drive for reading from or writing to a removable disk. The hard disk drive and disk drive are connected to the system bus via a hard disk drive interface and a disk drive interface, respectively. The drive and its associated computer-readable medium provide non-volatile storage of computer-readable instructions, data structures, program modules, and other data of the personal computer. While the exemplary environment described herein employs hard disks and removable disks, those skilled in the art will understand that other types of computer-readable media capable of storing computer-accessible data may also be used in the exemplary operating environment.

[0066] thrusters Figure 1 A perspective view of a thruster according to an embodiment of the present invention is presented. The thruster 100, or herein also referred to as a fully gimbaled ducted propeller, includes a propeller assembly configured in this embodiment to rotate clockwise when viewed from an outside position. A coordinate system is superimposed on the thruster, with its origin located at the aerodynamic center of the propeller assembly. The thrust plane is defined by orthogonal X-axis 102 and Z-axis 104 on the propeller assembly, and the Y-axis 106 extends along the nominal thrust axis direction. In this figure, the coordinate system is fixed in space along with the engine (not shown), drive shaft 110, and aircraft fuselage (not shown), regardless of the thruster's orientation.

[0067] refer to Figure 2A and Figure 2B This helps to understand the importance of vectored forces around the thrust center. Figure 2A This is a free-body force diagram according to an embodiment of the present invention, showing that the thrust 210 (or load) generated by the propeller 100 is guided through the aerodynamic center 220 of the propeller assembly. Assuming for... Figure 2A and Figure 2B The objective is to generate a desired clockwise control torque 230 in the YZ plane at the aircraft's center of gravity 240. As shown in the figure, the aerodynamic center 220 of the propeller assembly coincides with the pivot point of the thruster. Figure 2AThis is a side view of the thruster in the YZ plane. The thruster deflects around the pivot point / aerodynamic center 220° about the X-axis.

[0068] As shown, the engine 250 and drive shaft 110 are fixed relative to the aircraft's center of gravity (CG) 240 and its position along the Y-axis. The thruster 100 is shown pivoting at an angle 270 about its pivot point located at the thrust / aerodynamic center 220. The thrust vector 210 is decomposed into two components: a lateral component, which generates the desired control torque 230 by an angular deflection 270 acting about CG 240; and a thrust component 290, which remains aligned along the aircraft's centerline passing through CG 240. This makes the thruster 100 effective for both propulsion and control; the direction of the thrust vector remains unchanged as the torque 230 generated for controlling the aircraft changes in any plane through the pivot angle.

[0069] Figure 2B A direct comparison diagram of the present invention and similar tilt motor-propeller pairs well known to those skilled in the art is provided. The diagram presents a UZ plan view directly facing the tilt axis X. The tilt axis X is located inside the rotating propeller, typically at the center of mass of the engine 235, drive shaft, and propeller assembly to maintain control load balance. The propeller generates a force 215 acting on the propeller's center of rotation 220 (thrust center). This force is decomposed into a lateral component 285 and a translational component 245. As shown, an offset 278 from the thrust center generates an unfavorable translational force 245 at the thrust center 220 that is offset 278 from the longitudinal Y-axis. This results in an unfavorable torque 234, opposite to the desired control torque 235 generated by the lateral force vector 285. Because the two torques vary disproportionately with angle, the tilt motor-propeller pair becomes increasingly ineffective at larger tilt angles, thus limiting its application in aircraft control.

[0070] Figure 3 This is an exploded view of the main components of a thruster 100 according to an embodiment of the present invention. Figure 4 An end view of the thruster 100 is presented. Figure 5 This is a cross-sectional view of the thruster along the MM line.

[0071] Reference Figure 3 According to one embodiment of the present invention, the propeller 100 includes a propeller assembly 310, a propeller duct 320, an outer support 330, an inner support 340, a universal joint assembly 350, and a drive shaft 110 connected to a constant velocity universal joint (not shown). Figure 6 Provided Figure 3 The perspective view shown.

[0072] The propeller duct 320 is fixedly attached to the outer support 330 and the inner support 340, which together place the propeller assembly 310 within the center of the duct 320. The propeller assembly 310 includes a plurality of propeller blades (four are shown in this embodiment) located axially at the center of mass of the propeller duct.

[0073] The outer strut 330 serves as the primary load path for generating thrust loads (translational loads) for the propeller assembly 310. The two strut assemblies transfer radial loads back to the duct. These assemblies are manufactured from a variety of aerospace materials, are lightweight and highly rigid, as are well known to those skilled in the art, and will not be discussed further here. The propeller assembly 310 is located at the center of mass of the propeller duct 320, providing good tracking between the duct and the propeller to maintain tight tip clearance during dynamic movement of the assembly to manipulate the thrust vector.

[0074] The duct 320 and support assemblies 330 and 340 serve as a protective cover and support for the propeller assembly 310. The propeller duct 320 is geometrically and structurally similar to any standard ducted fan structure, except that its outer surface is slightly shaped to nest with the gimbal assembly 350. The propeller duct 320 possesses the known advantages of ducted fans, including improved propeller efficiency and reduced noise.

[0075] The entire propeller duct 320, including the propeller assembly 310 and two struts 330 and 340, is enclosed by a gimbal assembly 350. The propeller duct 320 is rotatably connected within the gimbal assembly 350 at a pivot interface 360, allowing the propeller duct 320 assembly to pivot about a single axis of rotation known as the propeller pivot axis 370. The gimbal assembly 350 includes two connection points 380 (gimbal pivot interfaces) where the gimbal assembly 350 and the contained propeller duct 320 are connected to the aircraft and are rotatable about the propeller gimbal pivot axis 390. The propeller gimbal pivot axis 390 is independent of the propeller pivot axis 370. Figure 3-6 In the illustrated embodiment, the propeller pivot axis 370 and the propeller gimbal pivot axis 390 are perpendicular to each other. In other embodiments of the invention, additional gimbal assemblies with alternative orientations are possible and considered, and are believed to be within the scope of the invention.

[0076] The universal joint 380 and the universal joint 360 create a fully biaxial universal joint thrust vectoring duct propeller. Figure 3-6 The thruster shown also includes multiple guide vanes 395 and a guide vane controller (not shown), which is configured to compensate for gyro precession, as discussed below.

[0077] like Figure 3-6As shown, the gimbal assembly 350 is rotatably connected to the propeller duct 320 at two points along the Z-axis passing through the center of the propeller assembly 310. The gimbal assembly 350 is nested within the outer surface of the propeller duct 320 and has a similar shape and structure. The gimbal assembly 350 is the load path that transmits forces from the propeller assembly 310 and the propeller duct 320 to the fuselage for propulsion and maneuvering of the aircraft.

[0078] The thruster assembly 310 can be configured for either a pull-in or a push-out configuration by reversing the orientation of the propeller duct 320, gimbal assembly 350, and propeller. The outer strut 330 is held on the outer side of the aircraft to transfer thrust loads to the fuselage, while the inner strut assembly 340 is held on the inner drive side to accommodate gimbal movement around the drive shaft. The direction of rotation of the propeller blades within the propeller assembly is independent of the mounting method and can be in either direction.

[0079] Constant velocity universal joint The propeller of propeller assembly 310 rotates with drive shaft 110 and pivots in association with propeller guide 320 and gimbal assembly 350. In one embodiment, propeller assembly 310 consists of any number of propeller blades with a fixed pitch at the hub. (See Figure 7A and...) Figure 7B As shown, the receiver housing 710, located at the thrust center (aerodynamic center) 750 of the propeller assembly, allows the propeller to move angularly in two dimensions while maintaining / transmitting rotational loads via the constant velocity universal joint 720.

[0080] A constant velocity universal joint (CV universal joint) 720 is a mechanical coupling that allows two shafts to rotate freely (without significantly increasing friction or backlash) and compensates for the angle between the two shafts within a certain range to maintain the same speed. Front-wheel-drive aircraft use CV universal joints to transmit engine power to the wheel assembly, even if the angle of the drive shaft changes due to suspension operation. Figures 7A and 7B show a tripod-type universal joint 720 (a type of CV universal joint) connecting drive shaft 110 to the propeller assembly. Figure 7A shows... Figure 5 The thruster is shown in a side sectional view at an angle to the Z-axis. Although the thruster 100 (including the propeller assembly) is at a deflection angle, the drive shaft 110 remains aligned with the Y-axis of the aircraft. Figure 7B and 7C This is an enlarged view of the interaction between the tripod-type universal joint and the propeller assembly.

[0081] The tripod-type universal joints in Figures 7A, 7B, and 7C are a form of constant velocity universal joint, which transmits uniform torque and constant speed despite angular variations, achieving consistent power transmission. Tripod-type universal joints are stronger and more compact than ball-type constant velocity universal joints and offer noise and vibration advantages due to their lower axial sliding resistance. Their angular travel capability is less than that of ball-type constant velocity universal joints. In the embodiments shown in Figures 7A and 7B, the tripod-type universal joint 720 consists of three spherical rollers mounted on a spider fitting. The spider fitting is axially engaged with the drive shaft via splines, and the three arms extend perpendicularly to the axis in an axisymmetric distribution, spaced 120 degrees apart. The rollers ride on needle roller bearings, allowing them to rotate freely about the axis of each arm. An important property of the tripod-type universal joint is its axial free travel, while simultaneously transmitting torque to accommodate the dynamic structural deformation of the propeller and aircraft. Those skilled in the art will understand that other CV universal joints can also be used with this invention without departing from the scope and novelty of the propellers described herein.

[0082] like Figure 7B As shown, a tripod-type universal joint 720 is fitted into a receiver housing 710 associated with the propeller assembly 310 and completes the universal joint via three mating grooves. Rotational motion of the shaft is transmitted via rollers that abut against the grooves in the receiver housing. These grooves allow the universal joint to operate relative to the receiver housing at dynamically changing angles, while simultaneously transmitting torque at high speeds.

[0083] The axial degree of freedom of the tripod-type universal joint accommodates the dynamic motion of the propeller caused by aerodynamic and thrust loads. In one embodiment of the invention, the axial degree of freedom 730 of the drive shaft relative to the propeller assembly is ±15 degrees. In other embodiments, the angular axial degree of freedom 730 is as large as ±30 degrees. Other degrees of freedom of motion of the propeller are possible and are considered to be within the scope of the invention.

[0084] The receiver housing of the tripod-type (CV) universal joint is mounted at the aerodynamic center 750 of the propeller assembly 310, within the propeller hub. The propeller hub includes two hub plates 760 connecting multiple outwardly radially extending propeller blades 780. A main bearing 785 is inserted between the propeller assembly 310 and the outer strut 330, transferring the loads generated by the propeller assembly to the outer strut 330. The main bearing 785 transfers the primary thrust load and radial load of the rotating propeller (propeller assembly) 310 to the non-rotating outer strut, and then to the aircraft. Similarly, an auxiliary bearing 795, inserted between the propeller assembly 310 and the inner strut 340, transfers radial loads but does not bear thrust or translational loads.

[0085] Mounted on the inner plate of the propeller hub is a sliding fitting that rotates with the hub and is connected via an auxiliary bearing to a non-rotatable inner strut assembly, which transfers radial loads to the non-rotatable inner strut. The sliding fitting has an oversized bore to allow the tripod to pass through it during installation and to provide rotational and angular clearance for the drive shaft during operation. In one embodiment, the sliding fitting is oversized to accommodate the collective assembly moving along its length.

[0086] The tripod-type universal joint and its associated housing are mounted in the propeller assembly in free airflow, away from the engine's heat. Any heat generated by the tripod bearing (CV universal joint) is conducted through the hub to the exposed bearing housings at both ends, enabling it to operate at high speeds and medium angles without excessive wear or thermal stress.

[0087] Thrust amplitude control The existing technology for changing the thrust of a fixed-pitch propeller is to change its rotational speed, which is not excluded in this invention. Figure 8 A four-bladed propeller assembly 310 according to a preferred embodiment of the present invention is shown. According to one embodiment of the present invention, such as... Figure 8 and Figure 9 As shown, each blade 780 includes a blade body 810 and a modifiable trailing edge 820 extending from the blade root at the hub to approximately two-thirds of the blade's total length. The blade body 810 includes a trailing edge 820 appendage that allows for modification of thrust while maintaining a constant propeller speed, or in combination with speed variations. In one embodiment of the invention, each propeller blade 780 in the propeller assembly is non-twisted, enabling the inclusion of lightweight surface hinges. Each blade is non-tapered to create a wide chord at the blade tip, which is curved to minimize the clearance between the blade tip and the propeller duct. Airfoil sections and blade pitch are selected to achieve optimal performance within the propeller duct. In one embodiment, each propeller blade has a hollow core 830 and an integrated sparsity 840 to minimize its rotational inertia.

[0088] According to one embodiment of the present invention, such as Figure 9 As shown, the trailing edge 820 can be connected to the blade via a strip hinge 850 or a similar device. Figure 9 In the illustrated version of the invention, hinge 850 allows the trailing edge to move up to 15 degrees in the direction of the upper surface of the blade and up to 25 degrees in the direction of the lower surface. The actuation of the trailing edge alters the thrust generated by the blade by changing the camber and lift coefficient of the root and midsection of the propeller blade, without changing the pitch of the blade itself, and importantly, without changing its interaction with the propeller duct.

[0089] The movable trailing edge modifies the camber of the propeller blades 780 during flight to provide efficient vertical takeoff and landing and forward flight, and to compensate for engine lag, which is particularly useful during turbine-powered or vertical takeoff and landing landings.

[0090] According to one embodiment of the present invention, the collective actuator assembly 1010 (such as...) Figure 10 (As shown in the cross-section) the trailing edge 820 of the propeller blades moves uniformly (i.e., collectively) within its angular range. The collective actuator assembly 1010 is driven by two opposing servos to move linearly along the length of the sliding fitting. The collective actuator assembly 1010 is divided into two subassemblies sharing a common derotating ball bearing. The rotating portion of the collective actuator assembly rotates with the propeller and the sliding fitting. It interfaces on the sliding fitting via a linear bearing and a pin inserted into a slot on the sliding fitting to transmit rotational torque, ensuring they rotate together. The rotating portion of the collective actuator assembly includes a spider plate having a spherical rod end connecting to the trailing edge of each propeller blade.

[0091] The derotating section of the collective assembly does not rotate. It is fixed to the rotating section via a common derotating ball bearing. The derotating plate extends radially outward and connects to two opposing yoke fittings in the inner strut assembly hub, driven by individual servos. The interface between the yoke fittings and the fixed servos restricts the derotating section from rotating with the rotating section. Commands to the drive servos cause the entire collective assembly to move along the length axis of the sliding fittings, ultimately moving the moving airfoil of the propeller blades.

[0092] During operation, the thrust vector is directed by the aircraft via push rods to the propeller duct and gimbal assembly. Figures 11A to 11I Various deflection configurations of the present invention relative to the concept aircraft are presented. Figure 11A The diagram shows the gimbal assembly 350 rotatably connected to the fuselage 1110 of the concept aircraft at two points along the X-axis via gimbal pivot interfaces 380. In this example, the gimbal pivot interface 380 is coplanar and orthogonal to the pivot interface along the Z-axis. The line connecting the gimbal pivot interface points passes through the center of the propeller assembly 310. (The X-axis is chosen in this example for simplicity; it should be understood that the connection can be on any axis within the XZ plane.) Figure 11B yes Figure 11A The thruster is shown in a reverse isometric side view, with the thrust vector 1120 displayed at the nominal thrust position, directly through the Y-axis. Figure 11C The propeller duct 320 and the included propeller assembly 310 are shown tilted about the X-axis, with a correspondingly tilted thrust vector 1120. Note again that the thrust vector is guided through the aerodynamic center 750 of the propeller assembly 310. Figure 11DThe diagram shows the gimbal assembly 350 tilting about the Z-axis, which in turn tilts the propeller duct 320, propeller assembly 310, and thrust vector 1120. Figure 11E The propeller duct 320 and gimbal assembly 350 are shown to be tilted in coordination to point the thrust vector 1120 in any desired direction relative to the Y-axis. Figures 11F to 11I Various depictions are provided showing how the independent movement of the propeller duct 320 and the gimbal assembly 350 results in the control of the thrust vector 1120.

[0093] Figure 12 A perspective view of a directional thrust free-tip propeller 1210 according to another embodiment of the invention is shown. A main bearing 1240 is inserted between an outer strut 1220 and a propeller assembly 1230. When the propeller blades rotate 1210 and generate thrust, the axial load generated by the propeller assembly is guided through an aerodynamic center 1260 and transmitted to the aircraft via the outer strut 1220 / main bearing. The strut 1220, and thus the propeller assembly 1230, are rotatably coupled via a pivot interface 1260. The pivot interface 1260 defines a propeller pivot shaft 1270 extending through the aerodynamic center 1260 juxtaposed with a CV gimbal. In one embodiment of the invention, the pivot interface 1260 is inserted between the outer strut 1220 and the aircraft. In another embodiment of the invention, the pivot interface 1260 is inserted between the outer strut 1220 and a gimbal assembly (not shown). In other embodiments, the outer strut transmits the load to a duct, which then transmits the load to the pivot interface.

[0094] gyroscope precession When thrust is vectored via a tilting rotating body (in this case, the thruster of the present invention), inertial effects, also known as gyro precession, must be taken into account. As taught in U.S. Patent 6,719,244 (Gress, 2004), the torque generated by the tilting rotating body can be large enough to control the aircraft. However, if its generation is unintended, it must be mitigated or counteracted.

[0095] Gyroscopic precession is a phenomenon where, when an external torque is applied, the axis of a rotating object (such as a gyroscope) moves along a circular path. This is due to the angular momentum of the rotating mass and the torque acting on it. When the object rotates, it possesses angular momentum (L). The direction of L is along the axis of rotation and is determined by the right-hand rule. Torque (T) is the rotational equivalent of force. It is defined as the rate of change of angular momentum: Gyroscope precession is the result of the interaction between angular momentum and external torque. When a torque is applied perpendicular to the axis of the rotating mass, the change in angular momentum causes the axis of rotation to move along a circular path instead of tipping over. This is why a gyroscope can maintain its orientation and resist changes in its axis of rotation.

[0096] The main considerations regarding inertial effects (such as gyroscope precession) are the mass and inertia of the rotating body, the rotational speed of the rotating body, the tilt or pivoting rate of the rotating body, and the position of the pivot axis relative to the rotating body.

[0097] For propellers, the optimal rotational speed for thrust and efficiency is typically determined by the desired speed at the propeller blade tip. Generally, ducted propellers rotate at much higher speeds than unshrouded propellers. Because the diameter of a ducted propeller is typically smaller than that of an unshrouded propeller, it must rotate much faster to achieve equivalent tip speed and thrust.

[0098] Increasing the rotational speed increases the centrifugal acceleration and gyroscopic precession (GP) torque of the components on the propeller assembly. The high rotational speed of the propeller blades in a ducted propeller configuration results in a greater centrifugal force than typically seen in slower-rotating, larger-diameter rotors. As will be understood by one of reasonable skill in the art, the mass and inertia of a rotating body are proportional to the adverse GP torque that body will generate.

[0099] To keep unwanted centrifugal loads and gyro precession torque within reasonable limits, the inertia of the rotating components must be minimized. Therefore, the mass of the pitch bearings used to change the propeller blade angle of attack and thus the blade thrust—typical in rotors or slower-rotating propellers—is impractical in ducted propeller applications. In one embodiment of the invention, multiple fixed-pitch propeller blades are used to eliminate the weight and inertia of the pitch bearings required for variable-pitch blades. In other embodiments of the invention, lightweight trailing edge portions and surface hinges are included to vary the thrust generated by the propeller assembly at the same propeller speed.

[0100] The gyroscopic precession force generated by the motion of the rotating mass can be transmitted back to the aircraft via the control system (whether a pushrod or a cable), ultimately affecting the aircraft's flight characteristics. Some aircraft counteract such moments during operation using their wings and control surfaces. Other aircraft may not have external controls to counteract them. One embodiment of the invention includes a gyroscopic precession compensation system that works in conjunction with the thrusters to reduce or eliminate any GP caused by the thrusters' directional thrust.

[0101] Gyro precession compensation (GPC) In one embodiment of the invention, the outer struts carry aerodynamic guide vanes 395. The leading and trailing edge surfaces of each outer strut act in coordination and interact with the outlet airflow of the propeller to generate a force perpendicular to the outer struts.

[0102] Reference Figure 13A and Figure 13BThe guide vane 395 of this invention serves as an active component of the gyro precession compensation system (GPC). Unlike control surfaces in typical aircraft, GPC can be used as needed to counteract unfavorable precession torques before they reach or are transmitted to the aircraft. During operation, the guide vane 395 moves in a non-intuitive direction, different from that of control surfaces, and only during active thruster tilting. The guide vane 395 returns to its neutral state immediately after the tilting motion ceases. This differs from typical control surfaces, which must remain deployed throughout the maneuver to generate the required control torque, increasing drag and energy loss. The instantaneous movement of the guide vane 395 in this invention to counteract gyro precession is aerodynamically more efficient than control surfaces that maintain a certain angle of attack to generate a reaction force throughout the maneuver duration.

[0103] Figure 13A The direction of the gyroscopic precession torque generated when the thruster of the present invention rotates 1310 in the pitch direction (about the X-axis) is shown. When the propeller duct 320 and gimbal assembly 340 move as a whole about the X-axis, a counterclockwise GP force 1330 is generated about the Z-axis. To counteract the GP torque tilting the thruster about the X-axis in the pitch direction, the GPC drives the guide vanes 395 in the orthogonal vertical direction (Z-axis) to counteract the gyroscopic effect, such as... Figure 13B As shown. In this example, the guide vane 395 on the Z-axis deflects the thrust, generating a force opposite to the direction of the guide vane deflection. Since the guide vane is not located at the aerodynamic center of the propeller blades, the force generated by the guide vane produces a torque. The blade deflection is controlled to generate a torque opposite to the GP torque.

[0104] Figure 14A The direction of the gyro precession torque is shown. Note that the guide vane 395 on the X-axis is not deflected because no GP is generated when the thruster is moved around the Z-axis or in the yaw direction. Figure 14B The diagram shows the deflection of the guide vanes on the X-axis to generate a downward force, which in turn produces a GPC reaction force 1430 against yaw tilt.

[0105] GPC calculates and counteracts the GP and external aerodynamic forces acting on the thruster during flight in real time.

[0106] The GPC of this invention includes a microprocessor 1410 and sensor suites 1420 and 1425 to determine the deflector actuation rate and angle required to counteract the thruster rotation (GP). A servo 1440 and a linkage mechanism, common in the art, move the control deflector. In one embodiment of the invention, the GPC and associated components are located in the propeller tail cone and do not require interaction with the main aircraft. In another embodiment, the microprocessor is mounted within the main aircraft, while the servo remains in the tail cone. Sensors 1420 and encoders at the gimbal pivot interface between the gimbal assembly and the aircraft fuselage, and another sensor 1425 at the pivot interface between the gimbal assembly and the propeller duct, along with a tachometer measuring the propeller rotation speed, measure the velocity of the airflow near the deflector to determine the amount of deflector deflection required for each propeller rotation.

[0107] Figure 15 A flowchart of a GP compensation method according to an embodiment of the present invention is presented. Process 1505 begins with encoder measurements 1510 of the command motion of the gimbal assembly and propeller ducts, and uses an onboard clock to determine 1520 the rate and direction of tilting (angle / velocity = rate). A tachometer 1530 provides the controller with the rotational speed of the propeller assembly—which has a known moment of inertia—allowing the controller to calculate 1540 the rotational inertia. Combining the tilt rate and rotational inertia, the controller determines 1550 the synthetic gyro precession torque. Sensors such as pitot tubes supply the controller 1560 with the airflow velocity (thrust) generated by the thruster. The controller then calculates 1570 the required vane deflection angle and deflection rate, and instructs 1580 the servos coupled to each vane to perform vane movement, ending 1595 of the process.

[0108] As will be understood by one of reasonable skill in the art, deflectors can also be used as conventional control surfaces. They can all rotate uniformly to sense roll torque on the primary aircraft, providing it with propulsion and three-axis control. Deflectors and ducts also provide aerodynamic steering capability to the primary aircraft by generating corrective yaw torque during gliding as a ring tail when thrust is lost or during spin landing.

[0109] As previously described, in a preferred embodiment, the thruster assembly is rotatably connected in two dimensions to the fuselage of the aircraft. The thruster of the present invention is as follows: Figure 16 As shown, control interfaces 1610 and 1620 for thruster manipulation are identified. Figure 17 A cross-sectional view of the aircraft fuselage at thruster connection point 1710 is provided. Figure 16 The propeller assembly shown is rotary coupled to the aircraft fuselage at two connection points (e.g.) Figure 17As shown), the drive shaft ends at a CV universal joint (such as a tripod universal joint) that interfaces with the propeller assembly. An additional interface (not shown) between the aircraft and the propeller is a pushrod, which typically extends from the aircraft to drive the control surfaces. Pitch and yaw pushrods connect to the propeller at two locations. The pitch pushrod connects to the propeller at the pitch interface, allowing the gimbal assembly to rotate about the X-axis at the gimbal pivot interface. The yaw pushrod connects to the propeller at the yaw interface, allowing the propeller duct to rotate about the Y-axis at the pivot interface.

[0110] The pushrod points in the direction of the thrust vector in the pitch and yaw directions and any combination thereof. The GPC guide vanes can be further used for aircraft roll via an additional electrical interface (not shown) to command the GPC servo. Note that there are no lateral or axial loads on the drive shaft.

[0111] Figure 18-23 Various aircraft equipped with the thrusters of this invention are presented. Figure 18 A typical reconnaissance unmanned aerial vehicle (UAV) with a twin-spike tail fin integrated with the present invention is shown. The airframe of the aircraft presents an ideal existing structure for propeller integration, as disclosed in U.S. Patent 11,447,246 (Kunz et al., 2022). The propellers in this type of aircraft are in a propulsive configuration with dual-axis tilting and optional thrust control. The integration of the propellers immediately behind the wing likely increases lift, and the dual-axis tilting enhances control in all directions. Optional thrust control provides drive to the trailing edge, allowing adjustment of the propeller camber at takeoff for better power and better efficiency during cruise flight.

[0112] Figure 19 This illustration shows an embodiment of the invention integrated into a blended wing-body flying wing aircraft. In this figure, the propeller is mounted in a propulsion configuration behind the wing, featuring dual-axis tilting, variable thrust, and GP deflectors with roll function. In this configuration, the invention serves simultaneously as both the propeller and the control system, eliminating the need for a tail and ailerons. By eliminating control surfaces and enclosed propeller blades, the aircraft's detectability is minimized.

[0113] The propeller can also be integrated in a pull-in configuration forward of the wing, or in both locations. Mounting the propeller forward simplifies the wing folding mechanism, as is commonly done in tail-sitting aircraft disclosed in U.S. Patent 10,287,013 (Starace et al., 2019). This invention retains the advantages of this configuration but reduces its complexity by eliminating the rotor cyclic pitch control mechanism used only in vertical and hover flight modes.

[0114] The configuration of two thrusters, one forward of the wing for a pull-in configuration and the other aft of the wing for a thrust-out configuration, represents a significant improvement over U.S. Patent 9,731,820 (Godlasky et al., 2017). Thrust vectoring capability eliminates the need for external motors and propellers for control during both vertical and horizontal flight phases. The tandem tilting of the two thrusters allows for rapid transitions between the two flight modes.

[0115] Figure 20 This illustration demonstrates the integration of the invention into a tail-sitting unmanned aerial vehicle (UAV). Tail-sitting UAVs typically transition from vertical takeoff and landing (VTOL) to horizontal flight to gain speed and range. They are particularly sensitive to ground winds in vertical mode, therefore the exposed wing area is usually minimized. One example is taught in U.S. Patent 9,365,290 (Morris, 2015), which discloses a ducted fan with control surfaces in the ducted slipstream and ailerons on the wing for control. The control surface chord must be very short to maximize clearance with the ground and its length is limited by the duct radius. The constraints on the wing and control surface surface areas limit the aircraft's maneuverability.

[0116] like Figure 20 The thruster shown is a propulsion configuration with dual-axis tilt, variable thrust, and a GPC for precession correction and roll. Integrating the thruster into a tail-sitting aircraft allows vectored thrust to provide control torque, rather than aerodynamic control surfaces dependent on slipstream velocity. Vectored control torque is greater than that achievable by control surfaces, especially during low-speed vertical flight and hovering. This integration enables better takeoff and landing control, faster transitions, and extreme evasive maneuvers in high wind conditions.

[0117] In all tailspin aircraft integrations, variable thrust can be rapidly adjusted during landing to compensate for any engine lag. Particularly important for all tailspin aircraft is that, upon takeoff from a sloping surface or a rolling ship deck, the thrusters, under the control of the flight controller, continuously pivot before takeoff to ensure vertical ascent regardless of the aircraft's initial direction. For fixed propellers or ducted fans, corrections are required upon leaving the sloping surface, which adversely affects their ability to maintain position.

[0118] Figure 21The integration of the propeller of the present invention into a rotorcraft is illustrated, configured as a propulsive type with dual-axis tilting and GP deflectors to counteract precession. In typical rotorcraft, the tail and control surfaces are located outside the propeller, presenting certain structural challenges. This places them within the slipstream of the high-speed propeller to improve its effectiveness in low-speed flight. The structure connecting the tail and fuselage imposes constraints on the propeller diameter. The interaction between the open propeller and the blade tip vortices with the structure is a known source of noise. U.S. Patent 9,868,507 (Meier et al., 2018) discloses a method for locally mitigating the noise caused by this interaction.

[0119] The integration of this invention into a rotorcraft eliminates the need for a tail, control surfaces, and their structures. It also eliminates propeller noise caused by tip vortices. The thruster in this configuration provides yaw control and pitch correction. The low-speed yaw control problem taught in U.S. Patent 9,611,037 (Groen, 2017) is solved by directly targeting the thrust vector rather than aerodynamic control surfaces. The ability to vectorize thrust in the pitch direction solves one of the main control problems of such aircraft: the varying pitch moment resulting from changes in thrust and main rotor drag. In the event of power loss, the thruster, along with its ducts and deflectors, can maneuver the aircraft in both pitch and yaw directions during a spin landing.

[0120] For compound rotorcraft with propellers mounted off-center and on the outer side of the wing, U.S. Patent 11,174,016 (Carter, 2021) teaches four fixed and tilted propeller-motor pairs for yaw and roll control. An improved variant is the thruster presented herein, which integrates single-shaft tilt and differential throttle control to reduce engine number, weight, and complexity.

[0121] Figure 22 A pull-in version of the invention integrated into a general aviation aircraft is shown. In this configuration, the aircraft can be controlled using its own control surfaces, and the thrusters add the advantage of enhanced control for extreme maneuvers and flight outside its normal envelope.

[0122] The maneuverability exceeds that taught in U.S. Patent Application 2024 / 0076066 (Moore et al., 2024), where thrust vectoring is possible only around a single axis (pitch). By fully gimbaling the thrusters, tilting the thrust to achieve yaw results in increased airflow around the opposite wing, providing greater lift and a natural roll tendency in the desired direction.

[0123] Figure 23This invention is illustrated when integrated into a propulsion-driven general aviation aircraft. In this integration, the propeller is configured as a propulsion-driven aircraft with dual-axis tilting. Similar to pull-type aircraft, the propeller enhances existing control systems and enables advanced capabilities, such as continuous in-flight adjustments to the aircraft based on fuel consumption and CG offset for better efficiency. Propeller noise, which is often caused by the limited diameter and high rotational speed, is reduced.

[0124] In both of these existing fixed-wing integrations, the need for GPC is reduced or eliminated because the aircraft has appropriate control surfaces, as the aircraft itself is able to counteract the precession torque. Although not shown, additional integrations include the use of propulsion systems in seaplanes to provide better takeoff performance and water-based turning capabilities, and their use in hovercraft and hovercraft to improve maneuverability.

[0125] In addition to improving the performance and capabilities of existing aircraft, this invention also enables many new types of aircraft.

[0126] The thrust vectoring propeller of this invention generates and controls two-dimensional vector thrust. The directional ducted propeller generates a propulsive thrust vector without producing adverse torque or translational forces. By pivoting the propeller's thrust plane and thrust center (i.e., aerodynamic center), the forces required to control the propulsive vector are minimized. When the propulsive thrust vector is independently guided, this invention maintains a fixed drive shaft orientation.

[0127] In one embodiment of the present invention, the system for a directional thrust propeller includes: A propeller assembly, wherein the propeller assembly includes a pneumatic center; A constant velocity (CV) universal joint connects the drive shaft to the propeller assembly, wherein the CV universal joint is juxtaposed with the aerodynamic center of the propeller assembly; and An outer strut is inserted between the propeller assembly and the pivot port, wherein the outer strut is configured to transfer the load generated by the propeller assembly to the pivot port, and wherein the outer strut and thus the propeller assembly are rotatably connected at the pivot port, the pivot port defining a propeller pivot axis extending through the aerodynamic center.

[0128] According to various embodiments of the present invention, other features of the system for directional thrust propellers as described herein include: The propeller assembly is mounted inside a propeller duct, and the propeller duct includes the pivot port.

[0129] The gimbal assembly includes a gimbal pivot interface that defines a propeller gimbal pivot axis extending through the aerodynamic center.

[0130] The propeller duct is rotatably connected to the gimbal assembly at the pivot interface.

[0131] The gimbal assembly is rotatable about the propeller gimbal pivot axis, the rotation being independent of the rotation of the propeller duct about the propeller pivot axis.

[0132] The gimbal pivot axis and the propeller pivot axis are perpendicular to each other.

[0133] A main bearing, inserted between the propeller assembly and the outer strut, is configured to transfer the load generated by the propeller assembly to the outer strut.

[0134] The loads mentioned therein include thrust loads and radial loads.

[0135] An inner support column is inserted between the propeller assembly and the propeller duct, and the inner support column is configured to transfer the radial load generated by the propeller assembly to the propeller duct.

[0136] An auxiliary bearing is inserted between the propeller assembly and the inner support.

[0137] The propeller assembly includes a plurality of propeller blades, and each propeller blade includes a blade root, a blade tip, a blade body and a trailing edge assembly, and each trailing edge assembly extends from the propeller root to a position not far from the blade tip.

[0138] The trailing edge assembly of each propeller blade is configured to collectively modify the camber of each propeller blade, thereby changing the load on the propeller assembly independently of the propeller assembly rotation speed.

[0139] The CV universal joint mentioned therein is a tripod-type universal joint.

[0140] The outer support includes a movable guide vane configured to counteract gyro precession.

[0141] In another embodiment of the present invention, the method for directional thrust includes: An outer strut is inserted between the propeller assembly and the pivot interface, wherein the outer strut is configured to transfer the load generated by the propeller assembly to the interface, and wherein the propeller assembly includes a pneumatic center. The outer strut is rotatably coupled at the pivot interface, which defines a propeller pivot axis extending through the aerodynamic center; The propeller assembly is coupled to the drive shaft via a constant velocity (CV) universal joint, wherein the CV universal joint is juxtaposed with the aerodynamic center of the propeller assembly; and The propeller assembly rotates about the propeller pivot axis, and the load generated by the propeller assembly is guided by the aerodynamic center.

[0142] Additional features of the method for directional thrust according to various embodiments of the present invention include: The propeller assembly is housed within the propeller duct.

[0143] The propeller duct is rotatably coupled within the gimbal assembly at the pivot interface, wherein the gimbal assembly includes a gimbal pivot interface that defines a propeller gimbal pivot axis extending through the aerodynamic center.

[0144] The gimbal assembly is rotated about the propeller gimbal pivot axis, the rotation being independent of the rotation of the propeller duct about the propeller pivot axis.

[0145] The gimbal pivot axis and the propeller pivot axis are perpendicular to each other.

[0146] A main bearing is inserted between the propeller assembly and the outer support to transfer the load generated by the propeller assembly to the outer support.

[0147] An inner support is inserted between the propeller assembly and the propeller duct to transfer the radial load generated by the propeller assembly to the propeller duct.

[0148] An auxiliary bearing is inserted between the propeller assembly and the inner support.

[0149] A main bearing is inserted between the propeller assembly and the outer support to transfer the load generated by the propeller assembly to the outer support.

[0150] The propeller assembly includes a plurality of propeller blades, and each propeller blade includes a blade root, a blade tip, a blade body and a trailing edge assembly, and each trailing edge assembly extends from the propeller root to a position not far from the blade tip, and also includes a method for collectively extending the trailing edge assembly of each propeller blade to change the load on the propeller assembly independently of the rotational speed of the propeller assembly.

[0151] The outer support includes a movable guide vane, and also includes a mechanism for positioning the movable guide vane to counteract gyroscope precession.

[0152] While the principles of the invention have been described above in conjunction with a fully universal joint duct propeller, it should be clearly understood that the above description is by way of example only and not intended to limit the scope of the invention. In particular, it should be recognized that the teachings disclosed above will suggest other modifications to those skilled in the art. Such modifications may involve other features known per se, which may replace or be used outside of the features described herein. Although claims have been made in this application with respect to specific combinations of features, it should be understood that the scope of this disclosure also includes any novel feature or any novel combination of features explicitly or implicitly disclosed herein, or any generalization or modification thereof that would be obvious to those skilled in the art, whether or not it relates to the same invention as claimed in any current claim, and whether or not it alleviates any or all of the same technical problems faced by the invention. The applicant hereby reserves the right to file new claims for such features and / or combinations of such features during the examination of this application or any further applications derived therefrom.

Claims

1. A directional thrust propeller system, characterized in that, The system includes: Propeller assembly 310, wherein the propeller assembly 310 includes a pneumatic center 220; A constant velocity (CV) universal joint 720 connects the drive shaft 110 to the propeller assembly 310, wherein the CV universal joint 720 is juxtaposed with the aerodynamic center 220 of the propeller assembly 310; and An outer strut 330 is inserted between the propeller assembly 310 and the pivot interface 360, wherein the outer strut 330 is configured to transfer the load 210 generated by the propeller assembly 310 to the pivot interface 360, and wherein the outer strut 330 and the propeller assembly 310 are rotatably connected at the pivot interface 360, the pivot interface 360 ​​defining a propeller pivot shaft 370 extending through the aerodynamic center 220.

2. The directional thrust propeller system according to claim 1, characterized in that, The propeller assembly is mounted inside a propeller duct, and the propeller duct includes the pivot port.

3. The directional thrust propeller system according to claim 2, characterized in that, The propeller system also includes a gimbal assembly, wherein the gimbal assembly includes a gimbal pivot interface that defines a propeller gimbal pivot axis extending through the aerodynamic center, and wherein the propeller duct is rotatably connected within the gimbal assembly at the pivot interface.

4. The directional thrust propeller system according to claim 2, characterized in that, The propeller system also includes a main bearing, which is inserted between the propeller assembly and the outer strut and is configured to transfer the load generated by the propeller assembly to the outer strut.

5. The directional thrust propeller system according to claim 1, characterized in that, The loads include thrust loads and radial loads. The system also includes an inner strut inserted between the propeller assembly and the propeller duct. The inner strut is configured to transfer the radial loads generated by the propeller assembly to the propeller duct and does not bear thrust loads.

6. The directional thrust propeller system according to claim 2, characterized in that, The propeller assembly includes a plurality of propeller blades, and each propeller blade includes a blade root, a blade tip, a blade body, and a trailing edge assembly, and each trailing edge assembly extends from the propeller root to a position not far from the blade tip, and the trailing edge assembly of each propeller blade is configured to collectively modify the camber of each propeller blade, thereby changing the load on the propeller assembly independently of the rotational speed of the propeller assembly.

7. The directional thrust propeller system according to claim 1, characterized in that, The outer support includes a movable guide vane configured to counteract gyro precession.

8. A method for generating directional thrust, characterized in that, The method includes: An outer support 330 is inserted between the propeller assembly 310 and the pivot interface 360, wherein the outer support 330 is configured to transfer the load 210 generated by the propeller assembly 310 to the pivot interface 360, and wherein the propeller assembly 310 includes a pneumatic center 220. The outer support 330 is rotatably connected at the pivot interface 360, which defines a propeller pivot shaft 370 extending through the aerodynamic center 220. The propeller assembly 310 is connected to the drive shaft 110 via a constant velocity (CV) universal joint 720, wherein the CV universal joint 720 is juxtaposed with the aerodynamic center 220 of the propeller assembly 310; and The propeller assembly 310 rotates about the propeller pivot axis 370, and the load 210 generated by the propeller assembly 310 is guided by the aerodynamic center 220.

9. The method for generating directional thrust according to claim 8, characterized in that, The method also includes installing the propeller assembly inside the propeller duct.

10. The method for generating directional thrust according to claim 9, characterized in that, The method further includes rotatably connecting the propeller duct to the gimbal assembly at the pivot interface, wherein the gimbal assembly includes a gimbal pivot interface that defines a propeller gimbal pivot axis extending through the aerodynamic center.

11. The method for generating directional thrust according to claim 10, characterized in that, The method further includes rotating the gimbal assembly about the propeller gimbal pivot axis, the rotation being independent of the rotation of the propeller duct about the propeller pivot axis.

12. The method for generating directional thrust according to claim 8, characterized in that, The propeller assembly includes a plurality of propeller blades, and each propeller blade includes a blade root, a blade tip, a blade body, and a trailing edge assembly, and each trailing edge assembly extends from the propeller root to a position not far from the blade tip, and also includes causing the trailing edge assemblies of each propeller blade to extend collectively, thereby changing the load of the propeller assembly independently of the rotational speed of the propeller assembly.

13. The method for generating directional thrust according to claim 8, characterized in that, The outer support includes a movable guide vane and a mechanism for positioning the movable guide vane to counteract gyroscope precession.

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