Three-tandem-wing dual-mode tilting ducted vertical take-off and landing aircraft

Abstract

The invention relates to a three-tandem-wing dual-mode tilting ducted vertical take-off and landing aircraft which comprises an aircraft body, wings arranged at the front section, the middle section and the rear section of the aircraft body and arranged in a bilateral symmetry mode, ducted propellers arranged at the ends of the three sections of the wings and an empennage, and the ducted propellers at the ends of the wings at the front section and the rear section of the aircraft body are fixedly connected with the corresponding wings. The ducted propellers at the ends of the wings of the middle section of the fuselage are in transmission connection with the corresponding wings, and the ducted propellers arranged on the four wings of the front section and the rear section provide vertical take-off and landing lift force and pitching moment in the flight state for the aircraft. The ducted propellers arranged on the middle-section wings provide extra thrust for the aircraft in a flying state; the problems of low lift-drag ratio and high energy consumption caused by pneumatic interference or redundant layout of the current aircraft are solved; a distributed power system aggravates flow field disorder, and flight stability is influenced; when a conventional tilting aircraft is switched between a vertical take-off and landing mode and a level flight mode, power distribution is uneven, and pitching torque unbalance is prone to being caused.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation aircraft, and relates to a three-tandem-wing dual-mode tilt-ducted vertical take-off and landing aircraft. Background Art

[0002] With the rapid development of drone technology, vertical take-off and landing aircraft have gradually become an important application in many fields. In particular, in scenarios such as urban air traffic, emergency rescue and logistics distribution, aircraft with vertical take-off and landing, high maneuverability and efficient cruising capabilities have shown huge market potential. Traditional vertical take-off and landing aircraft usually adopt a rotorcraft or tilt-rotor structure. Although they can meet the requirements of vertical take-off and landing by optimizing aerodynamic layout and designing redundant power systems to improve performance, they still have deficiencies in flight mode switching, flight stability, aerodynamic efficiency and energy consumption.

[0003] At present, there are many design schemes for aircraft with vertical take-off and landing capabilities, such as using different tail configurations and six-rotor layouts to reduce the impact of wing wake and propeller slipstream and improve flight efficiency; improving safety redundancy and endurance performance through forward-inclined multi-duct design; using conventional tandem wing and tail layouts, and achieving vertical take-off and landing and level flight through tilting devices. However, the traditional layout has insufficient lift or large resistance during level flight, resulting in high energy consumption and short endurance; there are problems such as uneven power distribution and complex attitude control during flight state conversion, which affect safety and stability; and although multi-rotor or redundant power systems improve safety, they increase energy consumption and limit range and endurance. Summary of the invention

[0004] In view of this, the present invention provides a three-tandem-wing dual-mode tilt-ducted vertical take-off and landing aircraft to solve the problems of low lift-to-drag ratio and high energy consumption of current aircraft due to aerodynamic interference or redundant layout; distributed power systems aggravate flow field turbulence and affect flight stability; conventional tilt-rotor aircraft have uneven power distribution when switching between vertical take-off and landing and level flight modes, which easily causes pitch moment imbalance. The invention achieves a comprehensive improvement in vertical take-off and landing efficiency, endurance, aerodynamic efficiency and safety redundancy.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A three-tandem wing dual-mode tilting ducted vertical take-off and landing aircraft, comprising a fuselage, wings arranged at the front, middle and rear sections of the fuselage and arranged symmetrically, ducted propellers installed at the ends of the three wing sections, and a tail wing, wherein the ducted propellers at the ends of the wings of the front and rear sections of the fuselage are fixedly connected to the corresponding wings, and the ducted propellers at the ends of the wings of the middle section of the fuselage are transmission-connected to the corresponding wings, and the ducted propellers arranged at the four front and rear sections of the wings provide the aircraft with lift for vertical take-off and landing and pitch moment in flight; and the ducted propellers arranged at the middle section of the wing provide the aircraft with additional thrust in flight;

[0007] The fuselage is equipped with a control system for controlling the seamless switching of the aircraft between the flight state, the tilt transition state and the vertical take-off and landing state, as well as a power system for providing power for the aircraft; when the aircraft is in the flight state, the ducted propellers at the ends of the wings in the middle section of the fuselage rotate to a vertical horizontal plane state that exhausts air toward the rear of the aircraft, and the duct faces the front of the fuselage, providing the forward thrust required for the aircraft to cruise; when the aircraft is in the vertical take-off state, the ducted propellers at the ends of the wings in the middle section of the fuselage rotate to a parallel horizontal plane state that exhausts air in the vertical direction of the aircraft, providing partial vertical lift required for vertical take-off, and at the same time, the fixed ducted propellers of the front / rear wings exhaust air toward the bottom of the fuselage, and the main lift is provided by the ducted propellers configured on the front and rear wings.

[0008] Furthermore, the wings adopt a three-tandem wing layout, which are a front wing located at the nose of the fuselage, a middle wing located in the middle of the fuselage, and a rear wing located at the end of the fuselage near the tail. The ducted propellers at the ends of the three wing sections of the fuselage are: a front fixed duct located inside the two ends of the front wing at the nose of the aircraft and fixedly connected to the front wing, a tiltable duct located at the two ends of the middle wing in the middle of the aircraft and transmission connected to the middle wing, and a rear fixed duct located inside the two ends of the rear wing at the end of the fuselage of the aircraft and fixedly connected to the rear wing. The propeller power formed by the front fixed duct and the rear fixed duct provides most of the power required for vertical take-off for the aircraft, and the propeller power formed by the tiltable duct provides additional level flight power and a small amount of power required for vertical take-off for the aircraft during flight.

[0009] Furthermore, the linkage mode between the front fixed duct and the front wing, and between the rear fixed duct and the rear wing is the same. Wing main shafts are installed through the front and rear wings. A duct-fuselage connection assembly is installed on the wing main shaft in the fuselage. Both ends of the duct-fuselage connection assembly are fixedly connected to a fuselage structure reinforcement shaft whose ends are fixedly connected to the fuselage. The wing main shaft is rigidly connected to the fuselage through the duct-fuselage connection assembly and the fuselage structure reinforcement shaft, thereby ensuring that the lift generated by the duct can be efficiently and directly transmitted to the fuselage structure.

[0010] Furthermore, the front fixed duct and the rear fixed duct both include a power system and a system propeller. The power system is fixedly installed at both ends of the wing main shaft. The output end of the power system is connected to the system propeller through a transmission shaft. The power system drives the system propeller to rotate at high speed to generate lift for the aircraft to take off and land vertically.

[0011] Furthermore, a transmission system connected to the tiltable duct is integrated in the middle wing. The transmission system includes a tilt mechanism and a reduction system used in conjunction with the tilt mechanism. The reduction system is connected to the tilt mechanism to adjust the output speed of the power system to adapt it to the working requirements of the tilt duct, thereby ensuring efficient transmission of power.

[0012] Furthermore, the tilt mechanism includes bearing I, bearing II and a transmission shaft arranged in the middle wing and passing through bearing I and bearing II. One end of the transmission shaft is transmission-connected to the output end of the reduction system, and the other end is rigidly connected to the tiltable duct, so as to drive the transmission shaft to rotate through the power output of the reduction system and drive the tiltable duct to tilt around its axis.

[0013] Furthermore, the tilt mechanism also includes a limiter, which is arranged at the connection between the duct outer shell and the mid-section wing, and includes a mechanical locking device, which is used to fix the ducted propeller through the limiter when the tiltable duct is rotated to a preset horizontal position or vertical position, so as to limit its rotation range and prevent unexpected relative displacement between the ducted propeller and the fuselage.

[0014] Furthermore, the reduction system includes a driving servo and a driving gear, an intermediate gear, and a driven gear that mesh with each other in sequence. The output shaft of the driving servo is transmission-connected to the driving gear, and both ends of the transmission shaft are respectively connected to the output shaft of the driven gear and the tiltable duct.

[0015] Furthermore, the driving servo serves as a power source, and its output shaft is rigidly connected to the driving gear through a keyway or spline to ensure the synchronization and reliability of power transmission; the driving gear meshes with the intermediate gear to transmit the rotational power to the intermediate gear. The intermediate gear serves as an intermediate transmission component, and its number of teeth matches the number of teeth of the driving gear and the driven gear, and is used to adjust the transmission direction and speed ratio to ensure the smoothness and efficiency of power transmission. The intermediate gear meshes with the driven gear to further transmit the rotational power to the driven gear. The driven gear is fixedly connected to the transmission shaft, and the transmission shaft passes through the driven gear and is rigidly connected through a keyway or spline to ensure that the rotational movement of the driven gear can directly drive the transmission shaft to rotate synchronously. The other end of the transmission shaft is rigidly connected to the tiltable duct to transmit the rotational power to the tiltable duct.

[0016] Furthermore, the tiltable duct includes a duct housing, a brushless motor, a tilting propeller mounted on the output shaft of the brushless motor, a motor mounting seat for mounting the brushless motor, a support beam and a support beam fixing seat, wherein the motor mounting seat is used to be fixedly connected to the transmission shaft to ensure that the brushless motor can rotate synchronously with the transmission shaft. The support beam fixing seat is a support base for the motor mounting seat, and is used to disperse the load of the brushless motor and the tilting propeller. A plurality of support beams whose ends are fixedly connected to the duct housing are arranged on the circumference of the support beam fixing seat, and the transmission shaft passes through the duct housing and is fixedly connected to the motor mounting seat.

[0017] Furthermore, the tilt propeller is directly mounted on the output shaft of the brushless motor through the shaft hole and fixed by a locking nut to ensure the stability and safety of the tilt propeller when rotating at high speed; the brushless motor adopts a high power density design, which can provide sufficient power output for the tilt propeller. The brushless motor is fixedly mounted on the motor mounting seat by bolts. The center of the motor mounting seat is provided with a through hole for fixed connection with the transmission shaft to ensure that the brushless motor can rotate synchronously with the transmission shaft; the motor mounting seat is rigidly connected to the support beam fixing seat by bolts. The support beam fixing seat serves as the supporting base of the motor mounting seat and is used to disperse the load of the brushless motor and the tilt propeller. The support beam fixing seat is fixedly connected to the duct shell through the support beam. The support beam adopts a plurality of radially distributed beam structures to enhance the overall rigidity and torsion resistance of the duct.

[0018] The beneficial effects of the present invention are:

[0019] 1. The three-tandem-wing dual-mode tilt-ducted vertical take-off and landing aircraft disclosed in the present invention adopts a streamlined fuselage, and is provided with a control system and a power supply system for realizing the smooth switching of the aircraft between the flight state, the tilt transition state and the vertical state; the wings are arranged on both sides of the fuselage and are divided into three sections, which are respectively located at the head, middle section and tail section of the fuselage, forming a three-tandem-wing layout; each section of the wing is finely designed according to the aerodynamic characteristics of the aircraft, and the angle of attack configuration is differentiated to meet the lift and drag balance requirements in different flight modes; the fixed ducted propellers are installed on both sides of the front and rear wings of the fuselage to provide lift and pitch moment; the tiltable ducted propellers are installed on both sides of the middle section of the fuselage, which can be turned to a vertical state in the flight state to provide forward power for the aircraft, and turned to a parallel horizontal plane in the vertical state to provide vertical lift. In this aircraft, the fixed ducted propellers are integrated with the wings, reducing the negative impact on the aerodynamic effect of the wings, thereby optimizing the overall aerodynamic performance. The brushless motor is fixed to both ends of the rigid connecting rod through a mounting bracket. The connecting rod is rigidly connected to the fuselage structure to enhance the overall structural stability and deformation resistance of the aircraft. The brushless motor drives the propeller in the duct, which is directly connected to the motor output end through the transmission shaft to ensure the high efficiency and stability of power transmission, improve the accuracy and reliability of flight operations, and ensure the stability and efficiency of the aircraft in various flight conditions. The aircraft of this application has achieved high-efficiency vertical take-off and landing and flight mode switching through a unique structural design, and has stronger stability, flight efficiency and lower energy consumption.

[0020] 2. The three-tandem wing dual-mode tilt-ducted vertical take-off and landing aircraft disclosed in the present invention is provided with a control system for switching between a flight state, a hovering state and a tilt state, and a power supply system required by the power system. Three sections of wings are symmetrically arranged on both sides of the fuselage, among which the middle section wing has the largest wing area, and tilt-adjustable ducted propeller assemblies are installed at both ends to optimize lift and cruise performance. The transmission system is integrated inside the middle section wing, and its transmission assembly includes a ducted transmission shaft, a ducted housing, a propeller, and a brushless motor to form an integrated tilt-ducted structure. Among them, the driven gear on the transmission shaft is connected to the driving gear driven by the servo, which can accurately control the tilt angle of the duct and achieve precise control of the omnidirectional tilt angle from 0° to 90°. Compared with the redundant ducted structure, the integrated transmission system reduces mechanical components and reduces aerodynamic resistance, ensuring the stability and efficiency of the aircraft in different flight modes. The present invention significantly improves the vertical take-off and landing efficiency and the stability of flight mode switching through the three-tandem wing layout and dual-mode tilt-ducted design. The large wing area in the middle section and the tiltable ducted propeller work together to provide sufficient lift while increasing cruising speed; the integrated ducts in the front and rear sections optimize aerodynamic efficiency, reduce induced drag, and enhance overall flight performance. The control system dynamically coordinates flight, hovering, and tilting state switching to ensure safety in all operating conditions. The integrated ducted transmission structure simplifies mechanical complexity and reduces maintenance requirements. Through the independent and mixed operation of the fixed ducts in the front and rear wings and the tiltable ducts in the middle wing, a more reasonable power distribution is achieved, energy consumption requirements are reduced, and speed, range, and endurance are improved.

[0021] 3. The three-tandem-wing dual-mode tilt-ducted vertical take-off and landing aircraft disclosed in the present invention has a dual-mode control mechanism. The middle duct can switch between pure lift mode and lift-thrust mixed mode. Combined with the aerodynamic coupling optimization of the three-section tandem wing, it eliminates the wake interference problem of the traditional tilt-rotor; the fixed and tilt-ducted support independent or collaborative operation modes, dynamically allocate power output, and reduce system energy consumption. Through the unique three-tandem wing layout and dual-mode tilt-ducted design, not only the switching stability of the flight mode is improved, but also higher aerodynamic efficiency and lower energy consumption can be provided in vertical take-off and landing and cruising flight. The adjustable tilt-ducted propeller of the aircraft is combined with the three-section wing structure, which can work together effectively, while improving lift and enhancing cruising speed, and dynamically adjust the flight state through the intelligent control system to ensure the safety and efficiency of the entire flight.

[0022] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0024] Figure 1 It is an axonometric view of the three-tandem-wing dual-mode tilt-ducted vertical take-off and landing aircraft of the present invention;

[0025] Figure 2 For the present invention Figure 1 Schematic diagram of the installation structure of the mid-front fixed duct;

[0026] Figure 3 For the present invention Figure 1 Assembly drawing of the medium tilting ducted transmission system;

[0027] Figure 4 For the present invention Figure 1 Assembly drawing of the tilting mechanism in the tilting duct transmission system;

[0028] Figure 5 For the present invention Figure 1 Axonometric drawing of the tiltable duct;

[0029] Figure 6 For the present invention Figure 1 Schematic diagram of the internal structure of the tiltable duct;

[0030] Figure 7 For the present invention Figure 1 Front view of the aircraft.

[0031] Figure numerals: fuselage 1, front wing 2, wing main shaft 211, fuselage structure reinforcement shaft 212, duct-fuselage connection assembly 213, power system 215, system propeller 216, front fixed duct 3, mid-section wing 4, bearing I 410, driven gear 412, bearing II 413, drive servo 415, driving gear 416, intermediate gear 417, tiltable duct 5, tilt propeller 510, duct housing 511, brushless motor 512, support beam fixing seat 513, support beam 514, motor mounting seat 515, bolt fastener 516, transmission shaft 7, rear fixed duct 8, rear wing 9, tail 10, rear fixed duct support shaft 11, fuselage cover 13, front fixed duct support shaft 14. DETAILED DESCRIPTION

[0032] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0033] In the description of the present application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0034] Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] In the related art, there are many design schemes for aircraft with vertical take-off and landing capabilities, such as twin-rotor, quad-rotor and tilt-rotor. However, most of these aircraft are designed with a single power source or a single wing shape, and often face problems such as low aerodynamic efficiency, high energy consumption and unstable mode switching. For example, although some common tilt-rotor aircraft can switch between vertical take-off and landing and fixed-wing flight modes, during the switching process, there are often long transition times and unstable flight, which affects the overall efficiency and performance of the aircraft.

[0036] In order to solve or partially solve the problems existing in the related art, the present application provides Figure 1 , Figure 7 The three-tandem-wing dual-mode tilt-ducted vertical take-off and landing aircraft shown in the figure has a fuselage whose front-to-back direction is the direction indicated by the X-axis, the lateral direction is the direction indicated by the Y-axis, and the longitudinal direction is the direction indicated by the Z-axis for easy understanding.

[0037] The three-tandem-wing dual-mode tilt-ducted vertical take-off and landing aircraft has a streamlined fuselage 1 to reduce air resistance and improve flight efficiency. A fuselage cover 13 is provided on the upper side of the front end of the fuselage 1. The fuselage cover 13 includes a transparent window for sightseeing. A control system for controlling the aircraft to seamlessly switch between the flight state, the tilt transition state and the vertical take-off and landing state is provided in the fuselage 1, as well as a power supply system for providing power to the aircraft to ensure the stability of energy supply.

[0038] The aircraft includes a fuselage 1, wings arranged at the front, middle and rear sections of the fuselage 1 and arranged symmetrically on the left and right, ducted propellers installed at the ends of the three wing sections, and a tail 10. The wings adopt a three-tandem wing layout, which are a front wing 2 located at the nose of the fuselage 1, a middle wing 4 located in the middle of the fuselage 1, and a rear wing 9 located at the end of the fuselage 1 near the tail.

[0039] The ducted propellers at the ends of the three wing sections of the fuselage 1 are: the front fixed duct 3 located inside the two ends of the front wing 2 at the nose of the aircraft and fixedly connected to the front wing 2, the tiltable duct 5 located at the two ends of the middle wing 4 at the middle part of the aircraft and transmission-connected to the middle wing 4, and the rear fixed duct 8 located inside the two ends of the rear wing 9 at the end of the fuselage 1 of the aircraft and fixedly connected to the rear wing 9. The propeller power formed by the front fixed duct 3 and the rear fixed duct 8 provides the aircraft with most of the power required for vertical takeoff, and the propeller power formed by the tiltable duct 5 provides the aircraft with additional horizontal flight power and a small amount of power required for vertical takeoff during flight. The two front fixed ducts 3 are integrated with the front wing 2, and the two rear fixed ducts 8 are integrated with the rear wing 9. Fixed ducted propellers are arranged on the left and right sides of the front and rear wings. They are mainly used to provide lift support and pitch moment adjustment during vertical take-off and landing, ensuring the attitude stability of the aircraft in hovering and transition states. They work in coordination with the tiltable ducted propellers to achieve dynamic distribution of power output and optimization of energy consumption.

[0040] When the aircraft is in flight, the tiltable duct 5 in the mid-wing 4 gradually rotates to a vertical horizontal plane as its transmission shaft 7 rotates, thereby increasing the flight speed of the aircraft. Specifically, the two tiltable ducts 5 at the ends of the mid-wing 4 rotate smoothly to a vertical horizontal plane that exhausts air toward the rear of the aircraft, thereby providing forward momentum for the aircraft in flight.

[0041] When the aircraft is in a vertical take-off state, the tiltable duct 5 in the middle wing 4 gradually rotates to a parallel horizontal plane state under the rotation of its transmission shaft 7, providing a small part of the lift required for vertical take-off, and the main lift is provided by the front fixed duct 3 in the front wing 2 and the rear fixed duct 8 in the rear wing 9; specifically, the two tiltable ducts 5 at the ends of the middle wing 4 rotate to a parallel horizontal plane state to exhaust air in the vertical direction of the aircraft, and the two front fixed ducts 3 and the two rear fixed ducts 8 in the front and rear wings all exhaust air toward the bottom of the aircraft to provide lift for the aircraft when it is in a vertical take-off state.

[0042] The four fixed ducted propellers on the front and rear wings provide the aircraft with lift for vertical take-off and landing and pitch moment in flight; the tiltable duct 5 on the middle wing 4 provides the aircraft with additional thrust in flight, and the tilt mechanism can achieve 0°~90° omnidirectional angle adjustment, supporting the switching between vertical take-off and landing and level flight mode;

[0043] The wing body is symmetrical at the front, middle and rear sections of the fuselage 1, and is wing-shaped. The thickness of the body is distributed longitudinally, and the width extends transversely, optimizing the aerodynamic shape to reduce induced drag and improve the lift-to-drag ratio. When the aircraft is in flight, the pressure difference between the upper and lower surfaces of the wing is increased due to a certain installation angle, which is used to increase the lift of the aircraft in level flight. By precisely designing the installation position and aerodynamic parameters of the three-section wing, it is ensured that the aircraft can obtain stable aerodynamic support and efficient flight performance in vertical take-off and landing, hovering and cruising. The middle section wing has the largest area and is integrated with a tiltable ducted propeller. The front and rear sections of the wing adopt a fixed duct structure to synergistically optimize the lift-to-drag ratio and flight stability.

[0044] like Figure 2 As shown, the front fixed duct 3 and the front wing 2 are linked in the same manner as the rear fixed duct 8 and the rear wing 9. The front fixed duct 3 and the front wing 2 are connected via the front fixed duct support shaft 14, and the rear fixed duct 8 and the rear wing 9 are connected via the rear fixed duct support shaft 11. Taking the connection between the front fixed duct 3 and the front wing 2 as an example, a wing main shaft 211 is installed through the front wing 2, and a duct-fuselage connection assembly 213 is installed on the wing main shaft 211 in the fuselage 1. Both ends of the duct-fuselage connection assembly 213 are fixedly connected to a fuselage structure reinforcement shaft 212 whose ends are fixedly connected to the fuselage 1. The wing main shaft 211 is rigidly connected to the fuselage 1 through the duct-fuselage connection assembly 213 and the fuselage structure reinforcement shaft 212, thereby ensuring that the lift generated by the duct can be efficiently and directly transmitted to the fuselage structure. The fuselage 1 is integrally connected to the front wing 2 through the fuselage structure reinforcement shaft 212 and the duct-fuselage connection assembly 213, making the fuselage structure more integrated and rigid, thereby significantly improving the overall structural strength and anti-deformation ability of the aircraft. The front fixed duct 3 includes a power system 215 and a system propeller 216. The power system 215 is fixedly installed at both ends of the wing main shaft 211. The output end of the power system 215 is connected to the system propeller 216 through a transmission shaft. The power system 215 drives the system propeller 216 to rotate at high speed to generate lift for the vertical take-off and landing of the aircraft.

[0045] In this embodiment, the front fixed duct 3 on the same section of the front wing 2 is symmetrically installed on both sides of the front wing 2, and the rear fixed duct 8 on the same section of the rear wing 9 is symmetrically installed on both sides of the rear wing 9. The front fixed duct 3 and the rear fixed duct 8 are driven to rotate by the power system 215 to provide a stable upward thrust. When the aircraft performs vertical take-off and landing, the front fixed duct 3 and the rear fixed duct 8 rotate at high speed under the action of the power system 215, and the four fixed duct propellers operate synchronously to generate sufficient lift to support the stable vertical take-off and landing of the aircraft. In addition, during the pitch attitude adjustment process of the aircraft, the front fixed duct 3 of the front wing 2 and the rear fixed duct 8 of the rear wing 9 form a lift difference between the front and rear wings by accurately controlling the rotation speed, thereby achieving precise pitch angle adjustment.

[0046] like Figures 3 to 6 In the tilt transmission relationship between the middle section wing 4 and the tiltable duct 5 shown, a transmission system connected to the tiltable duct 5 is integrated in the middle section wing 4. The transmission system includes a tilt mechanism and a reduction system used in conjunction with the tilt mechanism. The reduction system is connected to the tilt mechanism to adjust the output speed of the power system to adapt it to the working requirements of the tiltable duct 5 and ensure efficient power transmission. The transmission shaft 7 in the tilt mechanism is further connected to the tiltable duct 5, so that the ducted propeller can smoothly complete the tilting action under the drive of the transmission system. The power system is directly connected to the ducted propeller 510, and drives the ducted propeller to rotate through the transmission shaft 7, thereby providing the necessary thrust to achieve the propulsion and attitude control of the aircraft.

[0047] In this embodiment, the tilt transmission system is composed of a transmission system and a ducted propeller. Among them, the ducted propeller is rigidly connected to the tilt mechanism through a bolt fastener 516 to ensure transmission stability. The power system is installed inside the duct housing and fixed on the transmission shaft 7. Since the duct housing 511 is fixedly connected to the power system and the transmission shaft, the three can rotate synchronously, so that under the drive of the reduction system, the duct and its internal power system are driven to complete the tilting process. In the horizontal flight mode, the central axis of the tiltable ducted propeller rotates to be parallel to the central axis of the aircraft, and operates under the drive of the power system to provide forward thrust to meet the cruising requirements. When the aircraft performs vertical take-off and landing, the tilt mechanism drives the transmission shaft 7 to rotate, so that the central axis of the ducted propeller rotates to be perpendicular to the central axis of the aircraft. At this time, the ducted propeller provides partial upward thrust under the action of the power system, and cooperates with the fixed ducted propeller to complete the vertical take-off and landing operation. This design ensures that the aircraft can smoothly switch between different flight modes.

[0048] The tilting mechanism includes a bearing I 410, a bearing II 413 and a transmission shaft 7 which is arranged in the middle wing 4 and passes through the bearing I 410 and the bearing II 413. One end of the transmission shaft 7 is transmission-connected to the output end of the reduction system, and the other end is rigidly connected to the tilting duct 5, so as to drive the transmission shaft 7 to rotate through the power output of the reduction system, thereby driving the tilting duct 5 to tilt around its axis.

[0049] In addition, the tilt mechanism may also include a limiter, which is arranged at the connection between the duct outer shell 511 and the mid-section wing 4, and includes a mechanical locking device for fixing the ducted propeller through the limiter when the tiltable duct 5 is rotated to a preset horizontal position or vertical position, so as to limit its rotation range and prevent unexpected relative displacement between the ducted propeller and the fuselage 1.

[0050] The reduction system includes a driving servo 415 and a driving gear 416, an intermediate gear 417, and a driven gear 412 that mesh with each other in sequence. The output shaft of the driving servo 415 is connected to the driving gear 416, and both ends of the transmission shaft 7 are connected to the output shaft of the driven gear 412 and the tiltable duct 5 respectively.

[0051] In this embodiment, the driving servo 415 is used as a power source, and its output shaft is rigidly connected to the driving gear 416 through a keyway or a spline to ensure the synchronization and reliability of power transmission; when the driving servo 415 receives the command from the control system, its output shaft starts to rotate, driving the driving gear 416 to rotate synchronously. The driving gear 416 is meshed with the intermediate gear 417 to transmit the rotational power to the intermediate gear 417. The intermediate gear 417 is an intermediate transmission component, and its number of teeth matches the number of teeth of the driving gear 416 and the driven gear 412, which is used to adjust the transmission direction and speed ratio to ensure the stability and efficiency of power transmission. The intermediate gear 417 is meshed with the driven gear 412 to further transmit the rotational power to the driven gear 412. The driven gear 412 is fixedly connected to the transmission shaft 7. The transmission shaft 7 passes through the driven gear 412 and is rigidly connected through a keyway or a spline to ensure that the rotational movement of the driven gear 412 can directly drive the transmission shaft 7 to rotate synchronously. The other end of the transmission shaft 7 is rigidly connected to the tiltable duct 5, thereby transmitting the rotational power to the tiltable duct 5. When the transmission shaft 7 rotates, the tiltable duct 5 realizes a tilting movement around its axis. In the vertical take-off and landing mode, the driving servo 415 drives the transmission shaft 7 to rotate, so that the tiltable duct 5 rotates to a vertical position to provide the lift required for vertical take-off and landing; in the level flight mode, the driving servo 415 drives the transmission shaft 7 to rotate in the reverse direction, so that the tiltable duct 5 rotates to a horizontal position to provide the thrust required for level flight. The driving servo 415 is equipped with a high-precision encoder, which can provide real-time feedback on the rotation angle and position information of the transmission shaft 7. The control system adjusts the output angle and rotation speed of the driving servo 415 in real time according to the flight status (such as flight mode, hovering mode or tilting mode) to ensure the accuracy and stability of the duct tilting; when the tiltable duct 5 rotates to a preset horizontal position or vertical position, the limiter fixes the duct position through a mechanical locking device to prevent it from excessive rotation or interference with the fuselage 1.

[0052] The tiltable duct 5 includes a duct housing 511, a brushless motor 512, a tilting propeller 510 mounted on the output shaft of the brushless motor 512, a motor mounting seat 515 for mounting the brushless motor 512, a support beam 514 and a support beam fixing seat 513. The motor mounting seat 515 is used to be fixedly connected with the transmission shaft 7 to ensure that the brushless motor 512 can rotate synchronously with the transmission shaft 7. The support beam fixing seat 513 is a support base of the motor mounting seat 515, and is used to disperse the load of the brushless motor 512 and the tilting propeller 510. A plurality of support beams 514 whose ends are fixedly connected to the duct housing 511 are arranged around the support beam fixing seat 513, and the transmission shaft 7 passes through the duct housing 511 and is fixedly connected to the motor mounting seat 515.

[0053] The tilt propeller 510 is directly mounted on the output shaft of the brushless motor 512 through the shaft hole, and is fixed by a locking nut to ensure the stability and safety of the tilt propeller 510 when rotating at high speed; the brushless motor 512 adopts a high power density design, which can provide sufficient power output for the tilt propeller 510. The brushless motor 512 is fixedly mounted on the motor mounting seat 515 by bolts. The center of the motor mounting seat 515 is provided with a through hole for fixed connection with the transmission shaft 7 to ensure that the brushless motor 512 can rotate synchronously with the transmission shaft 7. The motor mounting seat 515 is rigidly connected to the support beam fixing seat 513 by bolts. The support beam fixing seat 513 serves as a supporting base of the motor mounting seat 515 and is used to disperse the load of the brushless motor 512 and the tilt propeller 510. The support beam fixing seat 513 is fixedly connected to the duct housing 511 through the support beam 514. The support beam 514 adopts a plurality of radially distributed beam structures to enhance the rigidity and torsional resistance of the duct as a whole. The duct housing 511 is fixedly connected to the transmission shaft 7 by bolt fasteners 516, and adopts a streamlined design to reduce air resistance and optimize aerodynamic performance. At the same time, a flow guide structure is provided inside it to improve the aerodynamic efficiency of the tilt propeller 510. The tiltable duct 5 is formed into an integrated whole through the above structure, and realizes the tilting movement around its axis under the drive of the transmission shaft 7. When the transmission shaft 7 rotates, the motor mounting seat 515, the support beam fixing seat 513, the support beam 514 and the duct housing 511 rotate synchronously, driving the tilt propeller 510 and the brushless motor 512 to tilt as a whole, thereby realizing the switching of the aircraft between the vertical take-off and landing mode and the level flight mode. In the vertical take-off and landing mode, the tiltable duct 5 rotates to a vertical position, and the tilt propeller 510 provides vertical lift. In the level flight mode, the tiltable duct 5 rotates to a horizontal position, and the tilt propeller 510 provides horizontal thrust.

[0054] In this embodiment, the tilt-ducted vertical take-off and landing aircraft has two main flight modes: vertical take-off and landing mode and cruise mode. The switching between the two modes is achieved through the coordinated work of the control system and the power system. Vertical take-off and landing mode: During the take-off or landing phase, the front fixed duct 3 on the front wing 2 and the rear fixed duct 8 on the rear wing 9 change the rotation speed at the same time to accelerate or decelerate. The upward lift generated by the left and right groups of front fixed ducts 3 and rear fixed ducts 8 remains the same to ensure the balance of the aircraft; then the limiter fixes the transmission shaft 7 to keep the tilt-duct 5 in a vertical state. At this time, the tilt-duct 5 provides a small amount of lift, while the front and rear four fixed duct propellers (3, 8) provide most of the lift, which together cause the fuselage 1 to maintain a stable ascending or descending state; during the vertical take-off and landing process, the tail 10 is used to adjust the longitudinal balance of the aircraft to ensure the stability of the aircraft's attitude.

[0055] Cruise mode: When the aircraft enters the cruise stage, the limiter cancels the fixation of the transmission shaft 7, and the transmission system starts to drive the transmission shaft 7 to rotate, so that the tiltable duct 5 gradually rotates; during forward flight, the central axis of the tiltable duct 5 gradually rotates to be parallel to the central axis of the fuselage 1. At this time, the limiter limits the transmission shaft 7 to prevent it from rotating beyond the limit; at the same time, the rotation speed of the power system in the tiltable duct 5 gradually increases to increase the level flight speed, while the rotation speed of the four front and rear fixed duct propellers (3, 8) gradually decreases; in this process, the lift provided by the four fixed duct propellers (3, 8) and the wings is sufficient to balance the gravity of the entire aircraft in the level flight state; when the cruising speed reaches the speed corresponding to the required lift provided by the wings, the rotation speed of the four fixed duct propellers (3, 8) drops to the minimum, and only a certain rotation speed is maintained to adjust the pitch attitude of the aircraft. When the aircraft needs to perform a rolling operation, the rolling movement is achieved by changing the lift of the two groups of fixed ducted propellers (3, 8) on the left and right. For example, when performing a left rolling movement, the fixed ducted propeller (3, 8) on the left side of the front and rear wings (2, 9) provides a smaller lift, while the fixed ducted propeller (3, 8) on the right side generates a larger lift, so that the overall lift on the left side is smaller than that on the right side, and the aircraft will roll to the left. The precise control of the rolling operation is achieved by adjusting the rotation speed of the fixed ducted propellers (3, 8) to ensure the stability and controllability of the aircraft during the rolling process. The pitch operation is achieved by adjusting the front and rear lift distribution of the aircraft. During the flight, the rotation speed of the fixed ducted propellers (3, 8) on the front and rear wings (2, 9) can be adjusted independently to change the distribution of the front and rear lift.

[0056] Specifically, the nose-up operation (nose-up): increase the rotation speed of the rear fixed duct 8 on the rear wing 9, and reduce the rotation speed of the front fixed duct 3 on the front wing 2, so that the rear lift is greater than the front lift, and the aircraft nose is lifted up; the nose-down operation (nose-down): reduce the rotation speed of the front fixed duct 3 on the front wing 2, and increase the rotation speed of the rear fixed duct 8 on the rear wing 9, so that the front lift is less than the rear lift, and the aircraft nose dives down. When the pitch operation needs to be implemented, the control system adjusts the speed difference of the fixed duct propellers (3, 8) on the front wing 2 and the rear wing 9 according to the flight attitude requirements. The yaw operation is achieved by adjusting the left and right thrust distribution of the aircraft. In the cruise mode, the thrust direction of the tiltable duct 5 can be fine-tuned by the tilt angle of the transmission shaft 7 to achieve asymmetric distribution of the left and right thrusts; increase the thrust of the right tiltable duct 5 and reduce the thrust of the left tiltable duct 5 at the same time, so that the right thrust is greater than the left thrust, and the aircraft deflects to the left; increase the thrust of the left tiltable duct 5 and reduce the thrust of the right tiltable duct 5 at the same time, so that the left thrust is greater than the right thrust, and the aircraft deflects to the right.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A three-tandem-wing dual-mode tilt-ducted vertical take-off and landing aircraft, characterized in that: The invention comprises a fuselage (1), wings arranged at the front, middle and rear sections of the fuselage (1) and arranged symmetrically on the left and right, ducted propellers installed at the ends of the three wing sections, and a tail wing (10), wherein the ducted propellers at the ends of the front and rear wing sections of the fuselage (1) are fixedly connected to the corresponding wings, and the ducted propellers at the ends of the middle wing section of the fuselage (1) are transmission-connected to the corresponding wings, and the ducted propellers arranged at the ends of the front and rear wings provide the aircraft with lift for vertical take-off and landing and pitch moment in flight; and the ducted propellers arranged at the middle wing section (4) provide the aircraft with additional thrust in flight; A control system for controlling the seamless switching of the aircraft between a flight state, a tilt transition state and a vertical take-off and landing state, and a power supply system for providing power to the aircraft are provided in the fuselage (1); when the aircraft is in a flight state, the ducted propeller at the end of the wing in the middle section of the fuselage (1) rotates to a vertical horizontal plane state for exhausting air toward the rear of the aircraft, and the duct faces the front of the fuselage, providing the forward thrust required for the aircraft to cruise; when the aircraft is in a vertical take-off state, the ducted propeller at the end of the wing in the middle section of the fuselage (1) rotates to a parallel horizontal plane state for exhausting air in the vertical direction of the aircraft, providing part of the vertical lift required for vertical take-off, and at the same time, the fixed ducted propellers of the front / rear section wings exhaust air toward the bottom of the fuselage (1), and the main lift is provided by the ducted propellers arranged on the front and rear wings.

2. The tilt-ducted vertical take-off and landing aircraft according to claim 1, characterized in that: The wings adopt a three-tandem wing layout, which are respectively a front wing (2) located at the nose of the fuselage (1), a middle wing (4) located at the middle part of the fuselage (1), and a rear wing (9) located at the end of the fuselage (1) near the tail. The duct propellers at the ends of the three wing sections of the fuselage (1) are respectively: a front fixed duct (3) located inside the two ends of the front wing (2) at the nose of the aircraft and fixedly connected to the front wing (2), a tiltable duct (5) located at the two ends of the middle wing (4) at the middle part of the aircraft and transmission-connected to the middle wing (4), and a rear fixed duct (8) located inside the two ends of the rear wing (9) at the end of the fuselage (1) of the aircraft and fixedly connected to the rear wing (9). The propeller power generated by the front fixed duct (3) and the rear fixed duct (8) provides most of the power required for vertical take-off of the aircraft, and the propeller power generated by the tiltable duct (5) provides additional level flight power and a small amount of power required for vertical take-off of the aircraft during flight.

3. The tilt-ducted vertical take-off and landing aircraft according to claim 2, characterized in that: The front fixed duct (3) and the front wing (2) as well as the rear fixed duct (8) and the rear wing (9) are linked in the same manner; a wing main shaft (211) is installed through the front wing (2) and the rear wing (9); a duct-fuselage connection assembly (213) is installed on the wing main shaft (211) in the fuselage (1); both ends of the duct-fuselage connection assembly (213) are fixedly connected to a fuselage structure reinforcement shaft (212) whose end is fixedly connected to the fuselage (1); the wing main shaft (211) is rigidly connected to the fuselage (1) through the duct-fuselage connection assembly (213) and the fuselage structure reinforcement shaft (212), thereby ensuring that the lift generated by the duct can be efficiently and directly transmitted to the fuselage structure.

4. The tilt-ducted vertical take-off and landing aircraft according to claim 3, characterized in that: The front fixed duct (3) and the rear fixed duct (8) both include a power system (215) and a system propeller (216); the power system (215) is fixedly mounted at both ends of the wing main shaft (211); the output end of the power system (215) is connected to the system propeller (216) via a transmission shaft; the power system (215) drives the system propeller (216) to rotate at high speed to generate lift for the vertical take-off and landing of the aircraft.

5. The tilt-ducted vertical take-off and landing aircraft according to claim 2, characterized in that: The middle section wing (4) is integrated with a transmission system connected to the tiltable duct (5), the transmission system comprising a tilt mechanism and a reduction system used in conjunction with the tilt mechanism, the reduction system being connected to the tilt mechanism to adjust the output speed of the power system so that it is adapted to the working requirements of the tiltable duct (5) and ensure efficient transmission of power.

6. The tilt-ducted vertical take-off and landing aircraft according to claim 5, characterized in that: The tilting mechanism comprises a bearing I (410), a bearing II (413), and a transmission shaft (7) arranged in the middle section of the wing (4) and passing through the bearing I (410) and the bearing II (413); one end of the transmission shaft (7) is connected to the output end of the reduction system by transmission, and the other end is rigidly connected to the tilting duct (5); the transmission shaft (7) is driven to rotate by the power output of the reduction system, and the tilting duct (5) is driven to tilt around its axis.

7. The tilt-ducted vertical take-off and landing aircraft according to claim 6, characterized in that: The reduction system comprises a driving servo (415) and a driving gear (416), an intermediate gear (417), and a driven gear (412) which mesh with each other in sequence. The output shaft of the driving servo (415) is connected to the driving gear (416) in a transmission manner, and the two ends of the transmission shaft (7) are respectively connected to the output shaft of the driven gear (412) and the tiltable duct (5).

8. The tilt-ducted vertical take-off and landing aircraft according to claim 7, characterized in that: The driving servo (415) serves as a power source, and its output shaft is rigidly connected to the driving gear (416) via a keyway or a spline to ensure the synchronization and reliability of power transmission; the driving gear (416) meshes with the intermediate wheel (417) to transmit the rotational power to the intermediate wheel (417); the intermediate wheel (417) serves as an intermediate transmission component, and its number of teeth matches the number of teeth of the driving gear (416) and the driven gear (412) to adjust the transmission direction and speed ratio to ensure the stability and efficiency of power transmission. The wheel (417) meshes with the driven gear (412) to further transmit the rotational power to the driven gear (412). The driven gear (412) is fixedly connected to the transmission shaft (7). The transmission shaft (7) passes through the driven gear (412) and is rigidly connected via a keyway or a spline to ensure that the rotational movement of the driven gear (412) can directly drive the transmission shaft (7) to rotate synchronously. The other end of the transmission shaft (7) is rigidly connected to the tiltable duct (5) to transmit the rotational power to the tiltable duct (5).

9. The tilt-ducted vertical take-off and landing aircraft according to claim 8, characterized in that: The tiltable duct (5) comprises a duct housing (511), a brushless motor (512), a tilting propeller (510) mounted on an output shaft of the brushless motor (512), a motor mounting seat (515) for mounting the brushless motor (512), a support beam (514) and a support beam fixing seat (513); the motor mounting seat (515) is used to be fixedly connected to a transmission shaft (7) to ensure that the brushless motor (512) can rotate synchronously with the transmission shaft (7); the support beam fixing seat (513) is a support base of the motor mounting seat (515) and is used to disperse the load of the brushless motor (512) and the tilting propeller (510); a plurality of support beams (514) whose ends are fixedly connected to the duct housing (511) are arranged around the support beam fixing seat (513); the transmission shaft (7) passes through the duct housing (511) and is fixedly connected to the motor mounting seat (515).

10. The tilt-ducted vertical take-off and landing aircraft according to claim 9, characterized in that: The tilt propeller (510) is mounted on the output shaft of the brushless motor (512) through a shaft hole, and the brushless motor (512) is fixedly mounted on the motor mounting seat (515) through bolts. A through hole is provided at the center of the motor mounting seat (515) for fixed connection with the transmission shaft (7) to ensure that the brushless motor (512) can rotate synchronously with the transmission shaft (7); the motor mounting seat (515) is rigidly connected to the support beam fixing seat (513) through bolts, and the support beam fixing seat (513) is fixedly connected to the duct casing (511) through the support beam (514).

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