A tandem twin-ducted fan aircraft

Abstract

The application discloses a longitudinal double-ducted fan aircraft, which comprises a fuselage, a longitudinal double-ducted fan assembly, a single-shaft tilting mechanism, a vector control mechanism and a central stabilizer wing assembly, the longitudinal double-ducted fan assembly comprises front and rear main ducted fans arranged in the longitudinal direction of the fuselage, and the installation positions of the front and rear main ducted fans have a height difference; the single-shaft tilting mechanism is arranged in correspondence with the duct shell, and each single-shaft tilting mechanism comprises a tilting fixed support, a tilting shaft, a tilting driving motor and a locking mechanism; the tilting driving motor drives the tilting shaft to rotate and drives the main ducted fan to rotate with the tilting shaft; the vector control mechanism comprises multiple groups of guide vane assemblies arranged at the outlet positions of the front and rear main ducted fans respectively; and the central stabilizer wing assembly is arranged on the top of the fuselage and between the front and rear main ducts. The application has the advantages of simple structure, low cost, high lift efficiency and strong adaptability to narrow environments.

Description

Technical Field

[0001] This invention relates to the field of aircraft technology, and specifically to a tandem dual-ducted fan aircraft. Background Technology

[0002] In recent years, UAV technology has developed rapidly, and vertical takeoff and landing (VTOL) aircraft have been widely used in urban low-altitude transportation, aerial operations, reconnaissance and monitoring, and other fields. Among them, ducted fan UAVs have become a research hotspot in the industry due to their compact structure, high safety, and low noise. Traditional ducted fan UAVs mostly adopt a distributed duct layout, equipped with duct protection structures, and the wings are mostly fixed structures. However, the distributed layout directly reduces flight stability and wind resistance; at the same time, it lacks an autonomous and efficient ground movement structure, and operations rely on external auxiliary devices; the fixed wing design also makes the aircraft prone to interference with walls and obstacles when operating in confined spaces, resulting in insufficient maneuverability; in addition, it lacks an integrated airflow rectification design, resulting in high drag during the forward flight phase and low flight efficiency.

[0003] In the prior art, for example, the invention patent with announcement number CN106347650B discloses a tandem dual-ducted flying robot and its dynamic cooperative control method. This scheme adopts a coaxial counter-rotating propeller plus a periodic pitch-changing mechanism, and changes the propeller pitch through a pitch-changing servo to achieve attitude control of the flying robot. Its shortcomings are: the transmission and pitch-changing structure is complex, including a large number of mechanical components such as a bevel gearbox, drive shaft, pitch-changing rod, and swashplate, which increases the system weight and maintenance cost; the duct is fixed and cannot tilt, and the horizontal thrust during forward flight depends on the rotor differential speed and pitch change, which limits aerodynamic efficiency; there is no auxiliary lift / thrust device, resulting in poor passability in narrow environments. Another example is the patent document with announcement number CN2753673Y, which discloses a tandem dual-ducted four-nozzle single-person aircraft, which adopts a layout of front and rear lift ducts plus independent thrust ducts. However, the lift ducts and thrust ducts are separated, resulting in low overall integration; the wings and ducts are both fixed structures, which cannot be folded or tilted, and the lateral dimensions are large, making it unsuitable for narrow environments. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings of the prior art and provide a tandem twin-ducted fan aircraft that can simultaneously achieve structural simplification, improved forward flight efficiency, passability in narrow environments, and ground maneuverability.

[0005] To achieve the above objectives, the present invention provides a tandem dual-ducted fan aircraft, comprising:

[0006] The fuselage has two ducted outer shells arranged longitudinally, front and rear.

[0007] A tandem dual-duct fan assembly includes a front main duct fan and a rear main duct fan respectively disposed within the two duct housings, wherein the front main duct fan is mounted at a lower position than the rear main duct fan; both the front and rear main duct fans include fan impellers and fan drive motors for driving the fan impellers to rotate.

[0008] Two single-axis tilting mechanisms are arranged corresponding to the two duct housings, one for each. Each single-axis tilting mechanism includes a tilting fixing bracket, a tilting shaft, a tilting drive motor, and a locking mechanism. The tilting fixing bracket is located on the outside of the duct housing and is fixedly connected to the machine body. The tilting shaft is radially inserted through the duct housing, and its two ends are rotatably connected to the tilting fixing bracket. The tilting drive motor drives the tilting shaft to rotate, thereby causing the corresponding duct housing and the main duct fan installed therein to tilt with the tilting shaft. The locking mechanism is connected to the tilting shaft and is used to lock the angle of the main duct fan after it has tilted into position.

[0009] The vector control mechanism includes two guide vane devices respectively disposed at the outlet positions of the front main duct fan and the rear main duct fan. Each guide vane device includes a central hub and multiple guide vane assemblies. The guide vanes of each guide vane assembly can deflect independently.

[0010] The central stabilizer assembly is located on the top of the fuselage and between the front and rear ducted outer shells.

[0011] Furthermore, each of the aforementioned guide vane devices is connected to the corresponding duct housing and can tilt with the corresponding single-axis tilting mechanism; the central hub is coaxially arranged with the duct housing, and each guide vane assembly includes a first drive motor, a guide vane, and a pivot shaft. The first drive motor is fixedly mounted on the inner wall of the duct housing; the blades of the guide vane are chordally arranged along the axial direction of the duct housing, and the pivot shaft is arranged radially along the duct housing and passes through the guide vane, with one end connected to the output end of the first drive motor and the other end rotatably connected to the central hub. In this structural configuration, the guide vane is driven by the first drive motor, enabling three-degree-of-freedom fine-tuning of pitch, roll, and yaw; it coordinates with the main duct tilting action for composite control: tilting is responsible for large attitude adjustment, while the guide vane is responsible for high-precision attitude stabilization and crosswind resistance; stable hovering and precise control can be achieved without control surfaces, tail rotors, or pitch control mechanisms.

[0012] Furthermore, the guide vane adopts a segmented flap-type variable camber structure and is divided into two parts along its airfoil chord direction, including a fixed main airfoil section and a deflectable flap section. The fixed main airfoil section is rigidly connected to the pivot shaft and can deflect as a whole with the pivot shaft. One end of the deflectable flap section is pivotally connected to the trailing edge of the fixed main airfoil section. A second drive motor and a bevel gear set are arranged in the cavity of the fixed main airfoil section. The second drive motor is connected to the bevel gear set for transmission to drive the deflectable flap section to deflect independently, thereby continuously changing the airfoil camber.

[0013] Furthermore, the tilt angle range of the single-axis tilting mechanism is 0° to 90°; where 0° is the vertical hovering state and 90° is the horizontal forward thrust state.

[0014] Furthermore, the locking mechanism is either an electromagnetic brake or a mechanical ratchet.

[0015] Furthermore, the central stabilizer assembly includes a central stabilizer body, small ducted fans, and a retraction drive mechanism. The central stabilizer body is connected to the fuselage via a clamping mechanism, and each of the left and right ends of the central stabilizer body is connected to a small ducted fan via the retraction drive mechanism. In this structural configuration, the central stabilizer assembly, connected to the fuselage via the clamping mechanism, serves both airflow rectification and attitude fine-tuning functions. The two small ducted fans on the left and right sides act as auxiliary tilt fan assemblies and can be driven independently. They are compact in structure and respond quickly. During the forward flight phase, they tilt to the horizontal direction to provide auxiliary forward thrust and increase cruise speed. During the hovering phase, they tilt vertically downward to provide auxiliary lift or attitude adjustment.

[0016] Furthermore, the folding drive mechanism includes a servo drive motor and a foldable wing surface. This mechanism drives the small ducted fan to switch between an extended working state and a folded, obstacle-avoiding state. The folding drive mechanism employs a combination of a servo motor and a foldable wing surface, enabling the small ducted fan to switch between an extended working state and a folded, obstacle-avoiding state, reducing lateral space occupation and adapting to passage through confined spaces.

[0017] Furthermore, the small ducted fan adopts a six-blade micro ducted fan structure.

[0018] Furthermore, a three-wheeled landing gear assembly is provided at the bottom of the fuselage. The three-wheeled landing gear assembly includes a front universal wheel at the front and two rear follower support wheels at the rear. The front universal wheel is connected to the front of the fuselage through a front landing gear link. The two rear follower support wheels are symmetrically distributed on both sides of the rear of the fuselage through a rear landing gear link, forming a stable triangular support with the front universal wheel.

[0019] Furthermore, the front landing gear link and the rear landing gear link are foldable structures, which can be folded up to the groove at the bottom of the fuselage during flight.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The stability and wind resistance are greatly improved by adopting a combination of tilting mechanism and guide vane device: the main duct tilting mechanism realizes a wide range of attitude adjustment, and the guide vane device realizes high-precision fine adjustment and crosswind resistance. The two work together to effectively solve the problems of slow attitude response and weak wind resistance of traditional fixed duct aircraft; the independent tilting of the front and rear ducts can realize differential tilting to generate pitch moment, and the response speed is greatly improved; the independent deflection of the guide vane device realizes roll and yaw control, without the need for tail nozzle wind vanes and complex wing surfaces, making the structure simpler.

[0022] (2) Seamless transition from hovering to forward flight, improved aerodynamic efficiency: The longitudinal double duct and streamlined fuselage significantly reduce forward flight drag, and the duct structure improves fan lift efficiency; in addition, the main duct fans are arranged in a longitudinal, low-front-high layout, and the duct single-axis tilt allows the fuselage to maintain a horizontal position to achieve lift and thrust switching without pitch oscillation, and the forward flight drag is significantly reduced; the small duct fans on the left and right sides of the top central stabilizer assembly can provide additional auxiliary lift, and the control redundancy is higher.

[0023] (3) Strong adaptability to narrow environments: The small ducted fans on the left and right sides of the top central stabilizer wing assembly can be folded and retracted through the folding drive mechanism, which greatly reduces the lateral space occupied by the aircraft and can effectively avoid interference with obstacles in confined spaces. This allows the aircraft of the present invention to flexibly shuttle through narrow alleys, dense buildings and other confined environments, and expand the operating range.

[0024] (4) Simplified structure and reduced cost: The fan drive motor adopts a direct drive motor to replace the complex transmission system, reducing mechanical parts, improving reliability, and reducing manufacturing and maintenance costs.

[0025] (5) Safety and reliability: The fan blades are wrapped with ducts (including the main duct fan and the small duct fans on the top left and right) to avoid low-altitude collision damage and blade scraping in complex and restricted environments; the symmetrical layout naturally balances the anti-torque and improves flight stability.

[0026] (6) Convenient ground operation: The three-wheeled landing gear forms a stable triangular support, and the front swivel wheel enables flexible steering. No external traction equipment is required, making it suitable for take-off, landing and movement in narrow spaces.

[0027] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0028] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0029] Figure 1 This is a schematic diagram of the overall configuration structure of a tandem dual-ducted fan aircraft according to the present invention;

[0030] Figure 2 This is a schematic diagram of the combined structure of the longitudinal double-duct assembly and the single-axis tilting mechanism in this invention;

[0031] Figure 3 This is a schematic diagram of the direct drive of the dual-duct fan motor in this invention;

[0032] Figure 4 This is a schematic diagram of the structure of the single-axis tilting mechanism and the vector control mechanism in this invention.

[0033] Figure 5 This is a schematic diagram of the flow guide plate in this invention;

[0034] Figure 6 This is a schematic diagram of the rotation angle of the guide vane in this invention; wherein: (a) is a schematic diagram of the guide vane rotating synchronously around the pivot axis; (b) is a schematic diagram of the independently adjustable deflectable flap section;

[0035] Figure 7 This is a schematic diagram of the tilting structure of the dual-duct fan in this invention;

[0036] Figure 8 This is a schematic diagram of the central stabilizer assembly in this invention;

[0037] Figure 9 This is a schematic diagram of the central stabilizer assembly in the folded state in this invention;

[0038] Figure 10 This is a structural schematic diagram of the three-wheeled landing gear assembly in the deployed state of the present invention;

[0039] Figure 11 This is a schematic diagram of the three-wheeled landing gear assembly in its folded state according to the present invention;

[0040] In the diagram: 1-Fuselage; 1.1-Groove; 2-Ductwork shell; 2a-Front main ducted fan; 2b-Rear main ducted fan; 2.1-Fan impeller; 2.2-Fan drive motor; 3-Single-axis tilting mechanism; 3.1-Tilting fixing bracket; 3.2-Tilting shaft; 3.3-Tilting drive motor; 3.4-Locking mechanism; 4-Guide vane assembly; 4a-Center hub; 4b-Guide vane assembly; 4.1-First drive motor; 4.2-Guide vane; 4.2a-Fixed main wing section; 4 4.2b-Deflectable flap section; 4.2c-Second drive motor; 4.2d-Bevel gear set; 5-Central stabilizer assembly; 5.1-Central stabilizer body; 5.2-Small ducted fan; 5.3-Folding drive mechanism; 5.4-Clamping mechanism; 6-Three-wheel landing gear assembly; 6.1-Front caster wheel; 6.2-Rear follower support wheel; 6.3-Front landing gear link; 6.4-Rear landing gear link; 7-Motor power cable; 8-Motor control module; 9-Motor mounting bracket. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent transformations or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0042] Please see Figures 1 to 8 This embodiment provides a tandem dual-ducted fan aircraft, including a fuselage 1, a tandem dual-ducted fan assembly, a single-axis tilt mechanism 3, a vector control mechanism, a central stabilizer assembly 5, and a three-wheeled landing gear assembly 6. This aircraft adopts an overall configuration of direct motor drive, single-axis pitch and tilt control of the main duct, vector control with built-in guide vanes in the duct, and auxiliary tilt fans. This achieves a unified approach of simplified structure, reduced cost, efficient lift and stable control, and operation in confined spaces, effectively addressing various related shortcomings of existing aircraft. The specific structure is as follows:

[0043] like Figure 1 As shown, the aircraft has an integrated streamlined shape. The fuselage 1 is an integrated streamlined fuselage, approximately 6m long, 3m wide, and 3m high. The integrated streamlined fuselage 1 integrates the dual ducted fans, ducted tilt mechanism, electric drive system, vector control mechanism, auxiliary tilt fan, and retractable landing gear into one unit, with a smooth surface transition, effectively reducing aerodynamic drag during forward flight. Specifically, two main ducts (approximately 2m in diameter) are arranged longitudinally along the fuselage 1, each containing a duct shell 2 that encloses the rotor, reducing friction with obstacles.

[0044] Combination Figure 2 and Figure 3As shown, the tandem dual-ducted fan assembly includes a front main ducted fan 2a and a rear main ducted fan 2b, arranged longitudinally within two duct housings 2. The front main ducted fan 2a is positioned lower than the rear main ducted fan 2b, creating a tilted layout with the front lower than the rear. This design reduces drag during hovering and forward flight transitions, improves pitch stability, prevents airflow interference, and optimizes the aircraft's center of gravity. Both the front and rear main ducted fans include a fan impeller 2.1 and a fan drive motor 2.2. The fan impeller 2.1 is driven by the fan drive motor 2.2, providing the primary lift. Each fan drive motor is connected to a motor control module 8 via a motor power cable 7 and is fixed by a motor mounting bracket 9. In this structural setup, the motor mounting bracket 9 is fixedly connected to the duct housing 2; each main duct fan is driven by a fan drive motor, eliminating the traditional drive shaft and bevel gearbox, simplifying the structure, reducing weight, and improving reliability; the duct smoothly connects to the fuselage curved surface, and the impeller is built-in to prevent the blades from colliding with external obstacles; this tilted layout can optimize forward flight aerodynamic efficiency and improve pitch stability during hovering and forward flight transitions.

[0045] like Figure 2 and Figure 4 As shown, the front and rear ducts are each connected to the integrated streamlined body 1 via an independent single-axis tilting mechanism 3, which can tilt independently around a horizontal axis. Each single-axis tilting mechanism 3 includes a tilting fixing bracket 3.1, a tilting shaft 3.2, a tilting drive motor 3.3, and a locking mechanism 3.4. The tilting fixing bracket 3.1 is located on the outside of the duct shell 2 and is fixedly connected to the body 1. The tilting shaft 3.2 is radially inserted through the duct shell 2, and both ends of the tilting shaft 3.2 are rotatably connected to the tilting fixing bracket 3.1. The tilting drive motor 3.3 is connected to the tilting shaft 3.2 via a reducer, and the locking mechanism 3.4 is mounted on the tilting shaft 3.2. The locking mechanism 3.4 uses an electromagnetic brake or a mechanical ratchet. After starting the tilt drive motor 3.3, the tilt drive motor 3.3 drives the tilt shaft 3.2 to rotate via the reducer, causing the entire duct assembly to tilt in a single axis of pitch around the tilt shaft 3.2, thereby achieving continuous adjustment of the angle between the duct axis and the vertical direction. Figure 5 As shown, the tilt angle range of the single-axis tilt mechanism 3 is 0° to 90°, meaning the tilt angle is continuously adjustable from 0° to 90° (wherein, the aircraft is in a vertical hovering state when the tilt angle is 0°, and in a horizontal forward thrust state when the tilt angle is 90°), enabling a seamless transition from vertical takeoff and landing to high-speed forward flight. After tilting to the correct position, the locking mechanism 3.4 automatically locks to prevent accidental deflection during flight. In this structural configuration, the front and rear main ducted fans can tilt independently or simultaneously, forming two combined modes: synchronous tilting for efficient forward flight; and differential tilting for enhanced pitch mode.

[0046] like Figure 4 As shown, the vector control mechanism includes two guide vane devices 4 located at the outlet positions of the front main duct fan 2a and the rear main duct fan 2b, respectively. The two guide vane devices 4 are respectively installed inside the two duct housings 2 and can be tilted with the corresponding single-axis tilting mechanism 3. The guide vane device 4 includes a central hub 4a and a plurality of guide vane assemblies 4b evenly arranged circumferentially along the duct housing. The central hub 4a is coaxially arranged with the duct housing 2. Each guide vane assembly includes a first drive motor 4.1, a guide vane 4.2, and a pivot shaft (not shown in the figure). The first drive motor 4.1 is fixedly mounted on the inner wall of the duct housing 2. One end of the pivot shaft is drivenly connected to the output end of the first drive motor 4.1, and the other end of the pivot shaft is rotatably connected to the central hub 4a. The pivot shaft is arranged radially along the duct housing and passes through the guide vane 4.2. The blades of the guide vane 4.2 are chordally arranged along the duct axis. Each guide vane 4.2 can deflect independently under the drive of its corresponding first drive motor. In this structural configuration, the first drive motor 4.1 is a waterproof servo drive motor, and each guide vane assembly is equipped with an independent drive motor, capable of driving a single guide vane to achieve independent deflection within the range of -25° to +25°. As a vector control mechanism, the servo motor drives the guide vane deflection to optimize airflow rectification: when roll is required, the left and right guide vanes deflect differentially, generating a roll torque around the longitudinal axis; when yaw is required, the front and rear duct guide vanes deflect differentially, generating a yaw torque around the vertical axis; duct tilt provides the main pitch control, and the guide vanes can deflect synchronously to assist in fine-tuning, improving response accuracy. The guide vane vector control and duct tilt complement each other and work together to achieve full-attitude vector control of the aircraft, eliminating the need for complex control surfaces such as ailerons, rudders, and elevators found in traditional fixed-wing aircraft.

[0047] like Figure 5 and Figure 6As shown, the guide vane 4.2 adopts an aerospace-grade segmented flap-type variable camber structure, and is divided into two parts along its airfoil chord: a fixed main wing section 4.2a at the front and a deflectable flap section 4.2b. One end of the deflectable flap section 4.2b is pivotally connected to the trailing edge of the fixed main wing section 4.2a. The fixed main wing section 4.2a is rigidly connected to the pivot shaft and serves as the main load-bearing structure of the guide vane 4.2, and can deflect as a whole with the pivot shaft. When the first servo drive motor 1 drives the pivot shaft to rotate, the fixed main wing section 4.2a deflects with the pivot shaft, thereby realizing the angle of attack adjustment of the guide vane 4.2. Two miniature second drive motors 4.2c are integrated within the enclosed cavity of the fixed main wing section 4.2a. Each second drive motor 4.2c is connected to a bevel gear set 4.2d, which includes a meshing driving bevel gear and a driven bevel gear. The driving bevel gear is located on the output shaft of the second drive motor 4.2c, and the driven bevel gear is located on a rotating shaft that rotatably connects the deflectable flap section 4.2b to the fixed main wing section 4.2a. When the second drive motor 4.2c drives the driving bevel gear to rotate, the driving bevel gear rolls circumferentially along the tooth surface of the driven bevel gear, thereby driving the deflectable flap section 4.2b to independently deflect within the range of -20° to +20° around the rotating shaft. This continuously changes the airfoil camber, and, in conjunction with the overall deflection of the guide vanes, achieves dual aerodynamic control of angle of attack and camber. Based on the connection and drive method of the segmented flap type continuous variable camber adaptive airfoil, the deflectable flap section 4.2b can be hinged to the trailing edge of the fixed main airfoil section 4.2a through a miniature precision titanium alloy rotating shaft. The second drive motor 4.2c in the closed cavity of the fixed main airfoil section 4.2a drives the flap section to achieve independent deflection within the range of -20° to +20°; the second drive motor is also a servo drive motor.

[0048] like Figure 1 , Figure 8 and Figure 9As shown, the central stabilizer assembly 5 is located on the top of the fuselage 1 and between the two main ducts. It includes a central stabilizer body 5.1, small ducted fans 5.2, and a folding drive mechanism 5.3. The central stabilizer body 5.1 is connected to the integrated streamlined fuselage 1 via a clamping mechanism 5.4. The central stabilizer body 5.1 has a flat rectangular structure and a length of approximately 3.5m. A small ducted fan 5.2 is connected to each of the left and right ends of the central stabilizer body 5.1 via the folding drive mechanism 5.3. The folding drive mechanism 5.3 is located at the connection points between the central stabilizer body 5.1 and the left and right small ducted fans, employing a foldable wing surface and a servo motor structure to realize the folding and unfolding actions of the left and right small ducted fans. The left and right miniature ducted fans 5.2 adopt a six-bladed micro ducted fan structure, symmetrically arranged on both sides of the folding drive mechanism. As auxiliary tilt fans, they can be driven independently to provide auxiliary lift and forward thrust, while also assisting in adjusting the fuselage attitude and improving hovering stability. The folding drive mechanism can drive the left and right miniature ducted fans to fold and fit against the central stabilizer body, significantly reducing the aircraft's lateral width and adapting to narrow and complex environments. When unfolded, they remain horizontal with the central stabilizer body, fully utilizing the auxiliary lift and attitude adjustment functions.

[0049] like Figure 10 and Figure 11 As shown, the three-wheeled landing gear assembly 6 adopts a three-wheeled landing gear layout with one wheel in front and two wheels behind: the front part consists of a front universal wheel 6.1 with a diameter of approximately 690 mm, connected to the front of the fuselage via a front landing gear linkage 6.3, allowing for 360° turning and bearing the main ground loads; the rear part consists of two rear follower support wheels 6.2 with a diameter of approximately 240 mm, symmetrically distributed at the rear of the fuselage via a rear landing gear linkage 6.4, forming a stable triangular support with the front universal wheel 6.1; the follower support wheels serve both steering and support functions. This landing gear enables stable parking, free taxiing, and turning on the spot, meeting the ground maneuvering requirements of large-sized aircraft. The landing gear linkage is a foldable structure, controlled by a landing gear drive motor and coupling, and can be folded upwards into a groove 1.1 at the bottom of the fuselage during flight, further reducing aerodynamic drag.

[0050] The implementation of a tandem dual-ducted fan aircraft operating mode according to the present invention includes:

[0051] Ground movement mode: The three-wheeled landing gear assembly is fully deployed, and the aircraft glides flexibly to the take-off and landing point via the front omnidirectional wheels; the small ducted fans on the left and right sides of the top central stabilizer are deployed, ready for take-off.

[0052] Vertical takeoff and landing mode: The front and rear main ducted fans rotate at high speed to provide the main lift, both at a 0° tilt angle (vertically upward), with the guide vanes centered; the central stabilizer assembly remains horizontal to suppress the pitch and roll of the fuselage and ensure smooth takeoff and landing, while the small ducted fans on the top left and right deploy to assist in stabilization and improve takeoff and landing stability.

[0053] Forward cruise mode: The flight control system controls the front and rear main ducted fans to tilt synchronously to 20° to 30° to generate a horizontal thrust component. Under extreme conditions, the front and rear ducts can tilt up to 90° to provide maximum horizontal thrust; the deflectors finely adjust the attitude; the left and right small ducted fans tilt to the horizontal direction to provide auxiliary forward thrust and further improve cruise efficiency; the three-wheeled landing gear assembly is fully retracted into the groove 1.1 at the bottom of the fuselage to reduce flight drag.

[0054] Pitch maneuver mode: Differential tilting of the front and rear main ducts, such as 10° for the front duct and 30° for the rear duct, generates a strong pitching moment, enabling short-distance climbs or rapid deceleration.

[0055] Roll / Yaw Maneuvering Mode: Rapid roll and yaw response is achieved through differential deflection of guide vanes, without the need for additional control surfaces.

[0056] Narrow space operation mode: The overall size of the aircraft does not exceed 3m at most, and the size including the top central stabilizer does not exceed 7m in normal state, which is suitable for most restricted spaces; if encountering an ultra-narrow and complex environment, the folding drive mechanism is activated to fold the small ducted fans on the left and right sides of the central stabilizer towards the center and fit them against the central stabilizer body, reducing the lateral space occupied and enabling flexible passage and operation.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A tandem dual-ducted fan aircraft, characterized in that, include: The fuselage (1) has two ducted outer shells (2) arranged longitudinally in front and behind it; The tandem dual-duct fan assembly includes a front main duct fan (2a) and a rear main duct fan (2b) respectively disposed in the two duct housings (2), wherein the installation position of the front main duct fan (2a) is lower than that of the rear main duct fan (2b); Two single-axis tilting mechanisms (3) are arranged corresponding to the two duct housings (2) respectively. Each single-axis tilting mechanism (3) includes a tilting fixing bracket (3.1), a tilting shaft (3.2), a tilting drive motor (3.3), and a locking mechanism (3.4). The tilting fixing bracket (3.1) is located on the outside of the duct housing (2) and is fixedly connected to the body (1). The tilting shaft (3.2) is radially inserted through the duct housing (2), and both ends of the tilting shaft (3.2) are rotatably connected to the tilting fixing bracket (3.1) respectively. The tilting drive motor (3.3) is used to drive the tilting shaft (3.2) to rotate, thereby causing the corresponding duct housing (2) and the main duct fan installed therein to tilt with the tilting shaft (3.2). The locking mechanism (3.4) is connected to the tilting shaft (3.2) and is used to lock the angle of the main duct fan after it has tilted into place. The vector control mechanism includes two guide vane devices (4) respectively disposed at the outlet positions of the front main duct fan (2a) and the rear main duct fan (2b). Each guide vane device (4) includes a central hub (4a) and multiple guide vane assemblies (4b). The guide vanes (4.2) of each guide vane assembly (4b) can deflect independently. The central stabilizer assembly (5) is located on the top of the fuselage (1) and between the front and rear ducted shells (2).

2. The tandem dual-ducted fan aircraft according to claim 1, characterized in that, Each of the guide vane devices (4) is connected to the corresponding duct housing (2) and can tilt with the corresponding single-axis tilting mechanism (3); the central hub (4a) is coaxially arranged with the duct housing (2), and each guide vane assembly includes a first drive motor (4.1), a guide vane (4.2) and a pivot shaft. The first drive motor (4.1) is fixedly arranged on the inner wall of the duct housing (2); the blade chord of the guide vane (4.2) is arranged axially along the duct housing (2), and the pivot shaft is arranged radially along the duct housing (2) and passes through the guide vane (4.2). One end of the pivot shaft is connected to the output end of the first drive motor (4.1), and the other end is rotatably connected to the central hub (4a).

3. The tandem dual-ducted fan aircraft according to claim 2, characterized in that, The guide vane (4.2) adopts a segmented flap-type variable camber structure and is divided into two parts along its airfoil chord direction, including a fixed main airfoil section (4.2a) and a deflectable flap section (4.2b). The fixed main airfoil section (4.2a) is rigidly connected to the pivot shaft and can deflect as a whole with the pivot shaft. One end of the deflectable flap section (4.2b) is pivotally connected to the trailing edge of the fixed main airfoil section (4.2a). A second drive motor (4.2c) and a bevel gear set (4.2d) are arranged in the cavity of the fixed main airfoil section (4.2a). The second drive motor (4.2c) is connected to the bevel gear set (4.2d) to drive the deflectable flap section (4.2b) to deflect independently, thereby continuously changing the airfoil camber.

4. The tandem dual-ducted fan aircraft according to claim 1, characterized in that, The tilt angle range of the single-axis tilting mechanism (3) is 0° to 90°; where 0° is the vertical hovering state and 90° is the horizontal forward thrust state.

5. The tandem twin-ducted fan aircraft according to claim 1, characterized in that, The locking mechanism (3.4) is either an electromagnetic brake or a mechanical ratchet.

6. The tandem dual-ducted fan aircraft according to claim 1, characterized in that, The central stabilizer assembly (5) includes a central stabilizer body (5.1), a small ducted fan (5.2), and a folding drive mechanism (5.3). The central stabilizer body (5.1) is connected to the fuselage (1) through a clamping mechanism (5.4). The left and right ends of the central stabilizer body (5.1) are respectively connected to a small ducted fan (5.2) through the folding drive mechanism (5.3).

7. The tandem twin-ducted fan aircraft according to claim 6, characterized in that, The folding drive mechanism (5.3) includes a servo drive motor and a foldable wing surface. The folding drive mechanism (5.3) is used to drive a small ducted fan to switch between an unfolded working state and a folded avoidance state.

8. The tandem dual-ducted fan aircraft according to claim 6, characterized in that, The small ducted fan (5.2) adopts a six-bladed micro ducted fan structure.

9. The tandem dual-ducted fan aircraft according to claim 1, characterized in that, The fuselage (1) is provided with a three-wheeled landing gear assembly (6) at the bottom. The three-wheeled landing gear assembly includes a front universal wheel (6.1) at the front and two rear follower support wheels (6.2) at the rear. The front universal wheel (6.1) is connected to the front of the fuselage through a front landing gear link (6.3). The two rear follower support wheels (6.2) are symmetrically distributed on both sides of the rear of the fuselage through a rear landing gear link (6.4), forming a stable triangular support with the front universal wheel (6.1).

10. The tandem dual-ducted fan aircraft according to claim 9, characterized in that, The front landing gear link (6.3) and the rear landing gear link (6.4) are foldable structures, which are folded up to the groove (1.1) at the bottom of the fuselage during flight.

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