Variable rotor duct system and tilt rotor aircraft

Abstract

The invention discloses a variable rotor duct system and a tilt rotor aircraft, and relates to the technical field of aircrafts, the variable rotor duct system comprises a transmission shaft, a rotor assembly and a duct assembly; the transmission shaft is in transmission connection with an aircraft body; the rotor assemblies are connected to the transmission shaft; the duct assembly comprises a deformation shell and a first driving mechanism, the first driving mechanism is connected to the transmission shaft, and the deformation shell is arranged outside the rotor wing assembly in a surrounding mode in the circumferential direction; the first driving mechanism is in transmission connection with the deformation shell, the first driving mechanism can drive the deformation shell to circumferentially expand in the direction away from the transmission shaft so as to form a duct configuration, and the first driving mechanism can further drive the deformation shell to circumferentially contract in the direction close to the transmission shaft so as to form a fairing configuration. According to the variable rotor duct system and the tilt rotor aircraft provided by the invention, the rotor duct system gives consideration to high hovering efficiency and low forward flight resistance, and the overall aerodynamic efficiency and engineering application value of the tilt rotor aircraft are improved.

Description

Variable rotor duct system and tiltrotor aircraft Technical Field

[0001] This invention relates to the field of aircraft technology, and in particular to a variable rotor duct system and a tiltrotor aircraft. Background Technology

[0002] Tiltrotor aircraft transition from helicopter mode to fixed-wing mode by tilting their rotors, achieving a balance between vertical takeoff and landing capabilities and high-speed cruise performance, and have received widespread attention in recent years. The rotor duct system, as its core component, directly determines the aircraft's efficiency, range, and energy consumption through its aerodynamic performance.

[0003] Rotor-driven ducted systems face drastically different, even contradictory, aerodynamic requirements under varying flight conditions. In helicopter / hover mode, high thrust efficiency and excellent induced flow control are necessary. However, in high-speed forward flight mode, the rotor and its associated structures exposed to the incoming airflow significantly increase drag and interference drag, severely limiting the aircraft's cruise efficiency and range. Existing tiltrotor aircraft mostly employ fixed-shape bare rotors or fixed ducted structures. While fixed ducts can improve aerodynamic efficiency during hovering, they significantly increase drag during forward flight due to their large frontal area and non-streamlined shape. Bare rotors also generate significant drag during forward flight, which is difficult to eliminate through structural means. Therefore, effectively reducing the aerodynamic drag of the rotor system in forward flight without sacrificing hovering performance has become a key technical challenge restricting the overall performance improvement of tiltrotor aircraft. Summary of the Invention

[0004] The purpose of this invention is to provide a variable rotor duct system and a tiltrotor aircraft to solve the problems existing in the prior art, so that the rotor duct system can achieve both high hovering efficiency and low forward drag, thereby improving the overall aerodynamic efficiency and engineering application value of the tiltrotor aircraft.

[0005] To achieve the above objectives, the present invention provides the following solution: The present invention provides a variable rotor duct system, including a drive shaft, a rotor assembly, and a duct assembly; the drive shaft is used for transmission connection to the aircraft body; the rotor assembly is connected to the drive shaft; the duct assembly includes a deformable shell and a first drive mechanism, the first drive mechanism is connected to the drive shaft, and the deformable shell is circumferentially surrounding the rotor assembly; the first drive mechanism is transmissionally connected to the deformable shell, and the first drive mechanism can drive the deformable shell to expand circumferentially in a direction away from the drive shaft to form a duct configuration, and the first drive mechanism can also drive the deformable shell to contract circumferentially in a direction close to the drive shaft to form a fairing configuration.

[0006] Preferably, the rotor assembly includes a blade assembly and a second drive mechanism. The second drive mechanism is fixedly connected to the drive shaft, the blade assembly is circumferentially disposed outside the drive shaft, and the second drive mechanism is drively connected to the blade assembly. The second drive mechanism can cause the blade assembly to rotate in a direction close to or away from the drive shaft. In the duct configuration, the second drive mechanism can drive the blade assembly to rotate in a direction away from the drive shaft to unfold. In the fairing configuration, the second drive mechanism can drive the blade assembly to rotate in a direction close to the drive shaft to fold, so that the blade assembly can be housed within the fairing configuration.

[0007] Preferably, the second drive mechanism includes a fixed part and a plurality of blade telescopic members; the fixed part is fixedly connected to the drive shaft, and the blade assembly is movably connected to the fixed part; the plurality of blade telescopic members are distributed circumferentially along the drive shaft, and each blade telescopic member is fixedly connected at one end to the drive shaft and at the other end to the blade assembly, and the blade telescopic members can extend and retract to drive the blade assembly to rotate vertically relative to the drive shaft.

[0008] Preferably, it also includes a hub cover, which is connected to the drive shaft; in the fairing configuration, the upper end of the deformed shell can circumferentially surround the hub cover.

[0009] Preferably, the outer wall of the propeller hub cover is configured as a convex curved surface.

[0010] Preferably, the deformed shell includes an upper shell assembly and a lower shell assembly. The first drive mechanism is connected to both the upper shell assembly and the lower shell assembly, and is rotatably connected to the drive shaft. The first drive mechanism can drive the upper shell assembly and the lower shell assembly to expand circumferentially away from the drive shaft and together form the duct configuration circumferentially around the drive shaft. The first drive mechanism can also drive the upper shell assembly and the lower shell assembly to contract circumferentially towards the drive shaft, so that the upper shell assembly and the lower shell assembly are circumferentially closed and surround the drive shaft. The upper shell assembly is placed on the upper side of the lower shell assembly and together with the lower shell assembly forms the fairing configuration.

[0011] Preferably, the upper shell assembly includes a plurality of circumferentially distributed upper shell plates, and the lower shell assembly includes a plurality of circumferentially distributed lower shell plates; the circumferential width of each upper shell plate gradually increases from top to bottom, and the circumferential width of each lower shell plate gradually decreases from top to bottom; in the duct configuration, the upper shell plates and the lower shell plates are sequentially staggered in the circumferential direction; in the fairing configuration, a plurality of upper shell plates are circumferentially joined and closed, and a plurality of lower shell plates are circumferentially joined and closed.

[0012] Preferably, the first driving mechanism includes an upper driving assembly and a lower driving assembly; the upper driving assembly includes a plurality of circumferentially distributed upper telescopic deflection driving members, and the lower driving assembly includes a plurality of circumferentially distributed lower telescopic deflection driving members; each of the upper shell plates is connected to the transmission shaft through one of the upper telescopic deflection driving members, and each of the upper shell plates is connected to the transmission shaft through one of the lower telescopic deflection driving members; both the upper telescopic deflection driving members and the lower telescopic deflection driving members can drive the corresponding upper shell plate and the lower shell plate to deflect vertically relative to the transmission shaft, and can move in a direction away from or close to the transmission shaft.

[0013] Preferably, the duct configuration is annular, and the fairing configuration is spindle-shaped.

[0014] The present invention also provides a tiltrotor aircraft, including an aircraft body and a variable rotor duct system as described in any of the preceding claims.

[0015] Compared with the prior art, the present invention achieves the following technical effects: The variable rotor duct system and tiltrotor aircraft provided by the present invention configure the duct component as a variable structure, and drive the variable shell to switch between the duct configuration and the fairing configuration through the first drive mechanism; During the hovering phase, the tiltrotor aircraft is dominated by rotor induced flow, and the duct configuration can effectively constrain the induced flow and reduce tip loss. Therefore, maintaining the duct configuration during hovering can improve rotor thrust efficiency and hovering aerodynamic performance; In high-speed forward flight, a fixed duct or exposed rotor structure will significantly increase the frontal area and drag. Therefore, the variable shell shrinks and transforms into a fairing configuration, while enclosing the rotor component. The fairing configuration has a highly streamlined shape, thereby effectively reducing forward flight drag and improving cruise efficiency; Therefore, the variable rotor duct system provided by the present invention can adaptively match the optimal aerodynamic configuration in different flight phases, taking into account both hovering efficiency and forward flight performance, which is beneficial to improving the range, energy utilization rate and engineering application adaptability of tiltrotor aircraft. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 is a schematic diagram of the external shape of the variable rotor duct system provided in this embodiment under the duct configuration; Figure 2 is a schematic diagram of the external shape of the variable rotor duct system provided in this embodiment under the fairing configuration; Figure 3 is an internal schematic diagram of the duct configuration of Figure 1 with the deformed shell removed; Figure 4 is a front view of Figure 3; Figure 5 is an internal schematic diagram of the fairing configuration of Figure 2 with the deformed shell removed; Figure 6 is a front view of Figure 5.

[0018] In the figure: 1-drive shaft; 2-rotor assembly; 21-blade assembly; 22-second drive mechanism; 221-fixed part; 222-blade telescopic component; 3-duct assembly; 31-deformed shell; 311-upper shell assembly; 312-lower shell assembly; 313-upper shell plate; 314-lower shell plate; 32-first drive mechanism; 321-upper drive assembly; 322-lower drive assembly; 323-upper telescopic deflection drive component; 324-lower telescopic deflection drive component; 4-hub cover; 5-upper rotating seat; 6-lower rotating seat. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The purpose of this invention is to provide a variable rotor duct system and a tiltrotor aircraft to solve the problems existing in the prior art, so that the rotor duct system can achieve both high hovering efficiency and low forward drag, thereby improving the overall aerodynamic efficiency and engineering application value of the tiltrotor aircraft.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] This embodiment provides a variable rotor duct system, as shown in Figures 1-6, including a drive shaft 1, a rotor assembly 2, and a duct assembly 3. The drive shaft 1 is used for transmission connection to the aircraft body. The rotor assembly 2 is connected to the drive shaft 1. The duct assembly 3 includes a deformable shell 31 and a first drive mechanism 32. The first drive mechanism 32 is connected to the drive shaft 1, and the deformable shell 31 is circumferentially surrounding the rotor assembly 2. The first drive mechanism 32 is transmissionally connected to the deformable shell 31. The first drive mechanism 32 can drive the deformable shell 31 to expand circumferentially in a direction away from the drive shaft 1 to form a duct configuration, and the first drive mechanism 32 can also drive the deformable shell 31 to contract circumferentially in a direction close to the drive shaft 1 to form a fairing configuration.

[0023] In this embodiment, the ducted assembly 3 is configured as a variable structure, and the first drive mechanism 32 drives the variable shell 31 to switch between the ducted configuration and the fairing configuration. During the hovering phase, the tiltrotor aircraft is dominated by rotor-induced flow, and the ducted configuration can effectively constrain the induced flow and reduce tip loss. Therefore, maintaining the ducted configuration during hovering can improve rotor thrust efficiency and hovering aerodynamic performance. In high-speed forward flight, a fixed duct or exposed rotor assembly 2 will significantly increase the frontal area and drag. Therefore, the variable shell 31 shrinks and transforms into a fairing configuration, while enclosing the rotor assembly 2. The fairing configuration has a highly streamlined shape, thereby effectively reducing forward flight drag and improving cruise efficiency. Therefore, the variable rotor duct system provided in this embodiment can adaptively match the optimal aerodynamic configuration in different flight phases, taking into account both hovering efficiency and forward flight performance, which is beneficial to improving the range, energy utilization rate and engineering application adaptability of the tiltrotor aircraft.

[0024] In the optional embodiments of this example, more preferably, the rotor assembly 2 includes a blade assembly 21 and a second drive mechanism 22. The second drive mechanism 22 is fixedly connected to the drive shaft 1, the blade assembly 21 is circumferentially disposed outside the drive shaft 1, and the second drive mechanism 22 is drively connected to the blade assembly 21. The second drive mechanism 22 can rotate the blade assembly 21 in a direction close to or away from the drive shaft 1. In the duct configuration, the second drive mechanism 22 can drive the blade assembly 21 to rotate in a direction away from the drive shaft 1 to unfold. In the fairing configuration, the second drive mechanism 22 can drive the blade assembly 21 to rotate in a direction close to the drive shaft 1 to fold, so that the blade assembly 21 can be stored in the fairing configuration.

[0025] To ensure that the rotor assembly 2 can rotate to provide lift and avoid spatial interference when the deformable shell 31 changes between the ducted and fairing configurations, in the ducted configuration, the second drive mechanism 22 can drive the blade assembly 21 to rotate away from the drive shaft 1 to unfold, and the drive shaft 1 can drive the blade assembly 21 to rotate to provide lift. In the fairing configuration, the second drive mechanism 22 can drive the blade assembly 21 to rotate closer to the drive shaft 1 to fold, so that the blade assembly 21 can be housed within the fairing configuration, avoiding interference between the blade assembly 21 and the housed deformable shell 31, allowing the deformable shell 31 to transform into the fairing configuration. This is achieved through the coordinated folding and rotating of the deformable duct assembly 31 and the rotor assembly 2. The same mechanism enables the rotor assembly 2 to adaptively match the optimal aerodynamic configuration at different flight stages, taking into account both hovering efficiency and forward flight performance, which is beneficial to improving the range, energy utilization rate and engineering application adaptability of the tiltrotor aircraft. In the optional scheme of this embodiment, more preferably, the second drive mechanism 22 includes a fixed part 221 and a plurality of blade telescopic members 222; the fixed part 221 is fixedly connected to the drive shaft 1, and the blade assembly 21 is movably connected to the fixed part 221; the plurality of blade telescopic members 222 are distributed circumferentially along the drive shaft 1, and each blade telescopic member 222 is fixedly connected at one end to the drive shaft 1 and at the other end to the blade assembly 21, and the blade telescopic members 222 can extend and retract to drive the blade assembly 21 to rotate vertically relative to the drive shaft 1.

[0026] The fixing part 211 can be configured as a fixing ring or a number of circumferentially distributed fixing hinges, which are fixedly installed on the transmission shaft 1 by welding or other means. The blade assembly 21 includes a number of circumferentially distributed blades, and the root of each blade is rotatably connected to the fixing ring or the corresponding fixing hinge. The blades can be vertically rotated relative to the fixing part 211. Each blade telescopic component 222 is configured as an electric or hydraulic telescopic rod, one end of which is fixedly connected to the transmission shaft 1 by welding or other means, and the other end is hinged to the corresponding blade by a pin. The corresponding blade is vertically rotated by telescopic drive.

[0027] In the optional scheme of this embodiment, more preferably, the variable rotor duct system provided in this embodiment also includes a hub cover 4, which is connected to the drive shaft 1; in the fairing configuration, the upper end of the variable shell 31 can circumferentially surround the hub cover 4.

[0028] The hub cover 4 can be used to seal the upper end of the deformed shell 31 in the retracted state, reducing the airflow entering the fairing during cruise and further reducing gas resistance. Specifically, the hub cover 4 can be rotatably connected to the drive shaft 1 via the upper rotating seat 5, and the upper rotating seat 5 can be rotatably connected to the drive shaft 1 via the bearing, and is relatively fixed in the axial direction. The hub cover 4 will not rotate synchronously with the drive shaft 1.

[0029] In the optional schemes of this embodiment, it is more preferred that the outer wall of the propeller hub cover 4 is set as a convex curved surface; specifically, the propeller hub cover 4 is set as a convex arc cover to further reduce gas resistance.

[0030] In the optional embodiment, more preferably, the deformed shell 31 includes an upper shell assembly 311 and a lower shell assembly 312. The first drive mechanism 32 is connected to both the upper shell assembly 311 and the lower shell assembly 312, and is rotatably connected to the drive shaft 1. The first drive mechanism 32 can drive the upper shell assembly 311 and the lower shell assembly 312 to expand circumferentially in a direction away from the drive shaft 1 and jointly form a duct configuration circumferentially around the drive shaft 1. The first drive mechanism 32 can also drive the upper shell assembly 311 and the lower shell assembly 312 to contract circumferentially in a direction close to the drive shaft 1, so that the upper shell assembly 311 and the lower shell assembly 312 are circumferentially closed and surround the drive shaft 1. The upper shell assembly 311 is placed on the upper side of the lower shell assembly 312 and forms a fairing configuration with the lower shell assembly 312.

[0031] In order to meet the conversion requirements of the modified shell 31 between the duct configuration and the fairing configuration, the modified shell 31 is set into two parts, namely the upper shell assembly 311 and the lower shell assembly 312. The upper shell assembly 311 and the lower shell assembly 312 can be unfolded under the action of the first drive mechanism 32 and spliced ​​together in the circumferential direction to form the duct configuration. In addition, in order to meet the upper and lower closure requirements of the fairing configuration, the upper shell assembly 311 and the lower shell assembly 312 can be retracted to the upper and lower sides respectively, so as to surround the folded rotor assembly 2 and form the fairing configuration to reduce aerodynamic drag.

[0032] In the optional embodiments of this example, more preferably, the upper shell assembly 311 includes a plurality of circumferentially distributed upper shell plates 313, and the lower shell assembly 312 includes a plurality of circumferentially distributed lower shell plates 314; the circumferential width of each upper shell plate 313 gradually increases from top to bottom, and the circumferential width of each lower shell plate 314 gradually decreases from top to bottom; in the duct configuration, the upper shell plates 313 and the lower shell plates 314 are sequentially staggered in the circumferential direction; in the fairing configuration, the plurality of upper shell plates 313 are circumferentially spliced ​​and closed, and the plurality of lower shell plates 314 are circumferentially spliced ​​and closed.

[0033] In order to enable the upper shell assembly 311 and the lower shell assembly 312 to be circumferentially docked and closed, and to achieve the conversion between the duct configuration and the fairing configuration, the upper shell assembly 311 is configured as a plurality of upper shell plates 313. Similarly, the lower shell assembly 313 is configured as a plurality of lower shell plates 314. The upper shell plates 313 are configured to gradually increase in circumferential width from top to bottom, and the lower shell plates 314 are configured to gradually decrease in circumferential width from top to bottom. This satisfies the docking dimensions of adjacent upper shell plates 313 and lower shell plates 314, as well as the circumferential docking closure between the plurality of upper shell plates 313 and the plurality of lower shell plates 314 in the fairing configuration.

[0034] In the optional embodiments of this example, more preferably, the first driving mechanism 32 includes an upper driving component 321 and a lower driving component 322; the upper driving component 321 includes a plurality of circumferentially distributed upper telescopic deflection driving members 323, and the lower driving component 322 includes a plurality of circumferentially distributed lower telescopic deflection driving members 324; each upper shell plate 313 is connected to the transmission shaft 1 through an upper telescopic deflection driving member 323, and each upper shell plate 313 is connected to the transmission shaft 1 through a lower telescopic deflection driving member 324; both the upper telescopic deflection driving member 323 and the lower telescopic deflection driving member 324 can drive the corresponding upper shell plate 313 and lower shell plate 314 to deflect vertically relative to the transmission shaft 1, and can move in a direction away from or close to the transmission shaft 1.

[0035] When the modified shell 31 is converted between the duct configuration and the fairing configuration, it involves the translation and deflection of the upper shell plate 313 and the lower shell plate 314. Therefore, the first drive mechanism 32 is set as an upper drive assembly 321 and a lower drive assembly 322 to drive the translation and deflection of the upper shell plate 313 and the lower shell plate 314 respectively. Specifically, the upper drive assembly 321 is equipped with a plurality of upper telescopic deflection drive members 323 to drive a plurality of upper shell plates 313 respectively, and the lower drive assembly 322 is equipped with a plurality of lower telescopic deflection drive members 324 to drive a plurality of lower shell plates 314 respectively.

[0036] Furthermore, a number of upper telescopic deflection drive components 323 are rotatably connected to the transmission shaft 1 via an upper rotating seat 5. The number of upper telescopic deflection drive components 323 are circumferentially fixedly distributed on the upper rotating seat 5. A number of lower telescopic deflection drive components 324 are rotatably connected to the transmission shaft 1 via a lower rotating seat 6. The number of lower telescopic deflection drive components 324 are circumferentially fixedly distributed on the lower rotating seat 6. The lower rotating seat 6 is rotatably connected to the transmission shaft 1 via a bearing and maintains axial relative fixation.

[0037] Specifically, the upper telescopic deflection drive 323 and the lower telescopic deflection drive 324 have the same structure and can be configured in multiple ways: Mode 1: Both include an electric or hydraulic telescopic rod and a deflection motor. The deflection motor is fixedly mounted on the upper rotating seat 5 or the lower rotating seat 6 by bolts. The drive end of the deflection motor is fixedly connected to the fixed end of the telescopic rod by bolts. The drive end of the telescopic rod is connected to the corresponding upper shell plate 313 or lower shell plate 314. The deflection motor can drive the telescopic rod and the corresponding upper shell plate 313 or lower shell plate 314 to deflect vertically. The telescopic rod can extend and retract to drive the corresponding upper shell plate 313 or lower shell plate 314 to translate to move closer to or away from the transmission shaft 1, as shown in Figures 4 and 6.

[0038] Method 2: Both include two electric or hydraulic telescopic rods. One end of the first telescopic rod is fixedly connected to the upper rotating seat 5 or the lower rotating seat 6 by bolts, and the other end is hinged to the corresponding upper shell plate 313 or lower shell plate 314. The two ends of the second telescopic rod are respectively hinged to the first telescopic rod and the corresponding upper shell plate 313 or lower shell plate 314. The first telescopic rod can extend and retract to drive the second telescopic rod and the corresponding upper shell plate 313 or lower shell plate 314 to translate. The second telescopic rod can extend and retract to drive the corresponding upper shell plate 313 or lower shell plate 314 to deflect vertically.

[0039] In the optional schemes of this embodiment, it is more preferred that the duct configuration is annular and the fairing configuration is spindle-shaped.

[0040] Specifically, the annular duct configuration can effectively constrain induced flow and reduce tip loss, thereby improving rotor thrust efficiency and hovering aerodynamic performance; the spindle-shaped fairing can enclose rotor assembly 2, with a highly streamlined shape, which can effectively reduce forward drag and improve cruise efficiency.

[0041] Example 2 This example provides a tiltrotor aircraft, including an aircraft body and a variable rotor duct system as in Example 1; the aircraft body can drive the drive shaft 1 of the variable rotor duct system to rotate and can provide the power and electricity requirements of the variable rotor duct system.

[0042] The duct component 3 of the variable rotor duct system is configured as a variable structure, and the first drive mechanism 32 drives the variable shell 31 to switch between the duct configuration and the fairing configuration. During the hovering phase, the tiltrotor aircraft is dominated by rotor-induced flow, and the duct configuration can effectively constrain the induced flow and reduce tip loss. Therefore, maintaining the duct configuration during hovering can improve rotor thrust efficiency and hovering aerodynamic performance. In high-speed forward flight, a fixed duct or exposed rotor component 2 will significantly increase the frontal area and drag. Therefore, the variable shell 31 shrinks and transforms into a fairing configuration, while enclosing the rotor component 2. The fairing configuration has a highly streamlined shape, thereby effectively reducing forward flight drag and improving cruise efficiency. Therefore, the variable rotor duct system provided in this embodiment can adaptively match the optimal aerodynamic configuration in different flight phases, taking into account both hovering efficiency and forward flight performance, which is beneficial to improving the range, energy utilization rate and engineering application adaptability of the tiltrotor aircraft.

[0043] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A variable rotor duct system, characterized in that: include: A drive shaft (1) is used for transmission connection to the aircraft body; a rotor assembly (2) is connected to the drive shaft (1); and a duct assembly (3) includes a deformable shell (31) and a first drive mechanism (32), the first drive mechanism (32) is connected to the drive shaft (1), the deformable shell (31) is circumferentially surrounding the rotor assembly (2); the first drive mechanism (32) is transmissionally connected to the deformable shell (31), the first drive mechanism (32) can drive the deformable shell (31) to expand circumferentially in a direction away from the drive shaft (1) to form a duct configuration, and the first drive mechanism (32) can also drive the deformable shell (31) to contract circumferentially in a direction close to the drive shaft (1) to form a fairing configuration.

2. The variable rotor duct system according to claim 1, characterized in that: The rotor assembly (2) includes a blade assembly (21) and a second drive mechanism (22). The second drive mechanism (22) is fixedly connected to the drive shaft (1). The blade assembly (21) is circumferentially disposed outside the drive shaft (1). The second drive mechanism (22) is drive-connected to the blade assembly (21). The second drive mechanism (22) can rotate the blade assembly (21) in a direction close to or away from the drive shaft (1). In the duct configuration, the second drive mechanism (22) can drive the blade assembly (21) to rotate in a direction away from the drive shaft (1) to unfold. In the fairing configuration, the second drive mechanism (22) can drive the blade assembly (21) to rotate in a direction close to the drive shaft (1) to fold, so that the blade assembly (21) can be housed in the fairing configuration.

3. The variable rotor duct system according to claim 2, characterized in that: The second drive mechanism (22) includes a fixed part (221) and a plurality of blade telescopic members (222); the fixed part (221) is fixedly connected to the drive shaft (1), and the blade assembly (21) is movably connected to the fixed part (221); the plurality of blade telescopic members (222) are distributed circumferentially along the drive shaft (1), and one end of each blade telescopic member (222) is fixedly connected to the drive shaft (1), and the other end is fixedly connected to the blade assembly (21). The blade telescopic members (222) can extend and retract to drive the blade assembly (21) to rotate vertically relative to the drive shaft (1).

4. The variable rotor duct system according to claim 1, characterized in that: It also includes a hub cover (4), which is connected to the drive shaft (1); in the fairing configuration, the upper end of the modified shell (31) can circumferentially surround the hub cover (4).

5. The variable rotor duct system according to claim 4, characterized in that: The outer wall of the propeller hub cover (4) is set as a convex curved surface.

6. The variable rotor duct system according to claim 1, characterized in that: The modified shell (31) includes an upper shell assembly (311) and a lower shell assembly (312). The first drive mechanism (32) is connected to both the upper shell assembly (311) and the lower shell assembly (312), and the first drive mechanism (32) is rotatably connected to the transmission shaft (1). The first drive mechanism (32) can drive the upper shell assembly (311) and the lower shell assembly (312) to expand circumferentially in a direction away from the transmission shaft (1) and circumferentially along the transmission shaft (1). Together they form the duct configuration; and the first drive mechanism (32) can also drive the upper housing assembly (311) and the lower housing assembly (312) to circumferentially contract in a direction close to the drive shaft (1), so that the upper housing assembly (311) and the lower housing assembly (312) are circumferentially closed and surrounded outside the drive shaft (1), and the upper housing assembly (311) is placed on the upper side of the lower housing assembly (312) and together with the lower housing assembly (312) form the fairing configuration.

7. The variable rotor duct system according to claim 6, characterized in that: The upper shell assembly (311) includes a plurality of upper shell plates (313) distributed circumferentially, and the lower shell assembly (312) includes a plurality of lower shell plates (314) distributed circumferentially; the circumferential width of each upper shell plate (313) gradually increases from top to bottom, and the circumferential width of each lower shell plate (314) gradually decreases from top to bottom; in the duct configuration, the upper shell plates (313) and the lower shell plates (314) are sequentially staggered in the circumferential direction; in the fairing configuration, a plurality of upper shell plates (313) are circumferentially joined and closed, and a plurality of lower shell plates (314) are circumferentially joined and closed.

8. The variable rotor duct system according to claim 7, characterized in that: The first drive mechanism (32) includes an upper drive assembly (321) and a lower drive assembly (322); the upper drive assembly (321) includes a plurality of circumferentially distributed upper telescopic deflection drive members (323), and the lower drive assembly (322) includes a plurality of circumferentially distributed lower telescopic deflection drive members (324); each of the upper shell plates (313) is connected to the transmission shaft (1) through one of the upper telescopic deflection drive members (323), and each of the upper shell plates (313) is connected to the transmission shaft (1) through one of the lower telescopic deflection drive members (324); both the upper telescopic deflection drive members (323) and the lower telescopic deflection drive members (324) can drive the corresponding upper shell plate (313) and the lower shell plate (314) to deflect vertically relative to the transmission shaft (1), and can move in a direction away from or close to the transmission shaft (1).

9. The variable rotor duct system according to claim 1, characterized in that: The duct has a ring-shaped configuration, and the fairing has a spindle-shaped configuration.

10. A tiltrotor aircraft, characterized in that: It includes the aircraft body and the variable rotor duct system as described in any one of claims 1-9.

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