Wing body fusion aircraft and control method thereof

Abstract

The invention discloses a wing body fusion aircraft and a control method thereof, the aircraft comprises an aircraft body, a left wing and a right wing, and the wing body fusion aircraft is characterized in that the total wingspan length of the aircraft is S; the length L of the machine body is larger than or equal to 0.4 S and smaller than or equal to 0.6 S; the chord length Lr of the wing roots of the ends, connected with the fuselage, of the left wing and the right wing meets the condition that Lr is larger than or equal to 0.2 S and smaller than or equal to 0.4 S; the wing tip chord length Lt of one end, far away from the fuselage, of each of the left wing and the right wing meets the condition that Lt is greater than or equal to 0.1 S and less than or equal to 0.2 S. Through collaborative innovation of pneumatic, power and structure, long-time and low-power-consumption continuous flight of the wing body fusion aircraft is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aircraft and power system design of aircraft, and particularly relates to a blended wing body aircraft and a control method thereof. BACKGROUND

[0002] In recent years, vertical take-off and landing aircraft have shown great application potential in large project fields such as crop monitoring, solar power plant inspection, etc. However, the existing mainstream vertical take-off (VTOL) solutions still have significant technical limitations in meeting long-time, high-efficiency and low-cost continuous monitoring tasks.

[0003] At present, the vertical take-off and landing aircraft on the market mainly follows the design path of mixing multi-rotor and fixed-wing, but both have inherent defects. Although the multi-rotor configuration has excellent hovering capability, its aerodynamic efficiency is low, the flight resistance is large, the speed is slow, the power consumption is high, the endurance time is short, and it is difficult to cover a large area. The fixed-wing configuration is more efficient in level flight, but to achieve vertical take-off, a complex tilting mechanism (such as tilting rotor or tilting wing) is usually introduced, which not only increases the weight, complexity and manufacturing cost of the system, but also brings higher failure rate and maintenance burden.

[0004] To optimize performance, various attempts have been made in the prior art. For example, US2020 / 0156785A1 discloses a modular vertical take-off and landing aircraft which adapts to different tasks through detachable wing components, but this modular design may lead to structural redundancy, complex connection mechanism, and does not fundamentally solve the problem of aerodynamic efficiency and power consumption. Chinese patent CN118004461A describes a composite unmanned aerial vehicle using counter-rotating ducted fans, which improves power efficiency, but its mechanical complexity is high, and the design focuses on cargo transportation, without optimizing the low-power consumption and high-endurance characteristics required for long-time monitoring tasks. In addition, traditional multi-rotor vertical take-off unmanned aerial vehicles represented by CN206598982U have great aerodynamic resistance due to their exposed rotors and support structures, which limits the flight speed (usually difficult to exceed Mach 0.5), and the control logic relies on multiple aerodynamic rudders, increasing the weight and control complexity. Another approach, as shown in CN107021208A, is a tail-sitter ducted unmanned aerial vehicle, which uses a duct design, but its double-fan configuration and rudder control method have deficiencies in control robustness and maneuverability.

[0005] In summary, the existing vertical take-off and landing aircraft in the prior art generally have the following key defects: 1. Limited flight time: limited by high-power flight modes (especially multi-rotor hovering and high-speed cruising), it is difficult to support long-time continuous monitoring of large projects.

[0006] 2. High power consumption: Multi-rotors are not very efficient when hovering and cruising, while fixed-wing aircraft with tilting mechanisms suffer significant energy loss during mode switching.

[0007] 3. Complex structure and high cost: The tilting mechanism, multi-rudder control system, and modular design adopted to enhance adaptability all greatly increase the complexity, weight and overall cost of the system.

[0008] 4. Insufficient flight speed: The design of traditional multi-rotor aircraft and poor aerodynamic shape makes them face huge air resistance during the cruise phase, which makes it impossible to achieve high-speed flight and limits mission efficiency.

[0009] Therefore, there is an urgent need in this field for an innovative vertical takeoff and landing (VTOL) aircraft solution that can integrate the flexibility of VTOL, the high efficiency of long endurance, the high-speed cruise capability, and the simplified, reliable, and low-cost design to truly meet the urgent needs of modern agriculture, energy, and other fields for large-scale, continuous, and autonomous monitoring. Summary of the Invention

[0010] This invention aims to overcome the technical deficiencies of existing vertical takeoff and landing (VTOL) aircraft in terms of endurance, efficiency, and cost, and to provide a high-performance VTOL aircraft and its control method that integrates long endurance, low power consumption, high-speed cruise, and low cost. Its core objective is to achieve efficient, sustained, and autonomous operation of the aircraft in large-scale project monitoring missions through synergistic innovation in aerodynamics, propulsion, and structure.

[0011] To address the aforementioned problems, a first aspect of the present invention provides a blended wing-body aircraft, the aircraft comprising a fuselage, a left wing, and a right wing, the total wingspan of the aircraft being S; the length L of the fuselage satisfying: 0.4S≤L≤0.6S; the root chord length Lr of the left and right wing at the end connected to the fuselage satisfying: 0.2S≤Lr≤0.4S; and the wingtip chord length Lt of the left and right wing at the end furthest from the fuselage satisfying: 0.1S≤Lt≤0.2S.

[0012] Furthermore, the total wingspan S of the aircraft ranges from 0.5 to 10 m; both the left and right wings have a sweep angle of 30° to 60°.

[0013] The blended wing-body aircraft with specific proportional parameters provided in this application is characterized by constraining the fuselage length, wing root width, and wingtip width within a fixed proportion to the total wingspan, coupled with a large sweep angle of 30° to 60°. This structural design effectively reduces interference drag through a smooth transition of the blended wing-body, optimizes lift distribution and weakens wingtip vortices by optimizing the trapezoidal configuration of the wide wing root and narrow wingtip, thereby reducing induced drag, while the large sweep angle enhances high-speed flight performance and delays shock wave generation.

[0014] Furthermore, the aircraft also includes: a main ducted fan propulsion device located above the tail of the fuselage; a left ducted fan propulsion device and a right ducted fan propulsion device, respectively symmetrically located below the left wing and the right wing; the three propulsion devices receive control commands from the ground control system or the onboard control system to coordinate the vertical takeoff and landing, pitch, yaw and cruise control of the aircraft.

[0015] Furthermore, the aircraft also includes an onboard control system, which is electrically connected to the main ducted fan propulsion device, the left ducted fan propulsion device, and the right ducted fan propulsion device, for controlling the thrust of the three propulsion devices to coordinate the vertical takeoff and landing, pitch and yaw control of the aircraft.

[0016] This aircraft employs a three-ducted propulsion layout—with the main ducted fan positioned above the tail and the left and right ducted fans symmetrically arranged below the wings—to work in conjunction with a blended wing-body structure. This creates a flight control system based on pure thrust vectoring: the main duct provides the primary lift and pitch control torque, while the left and right ducts achieve yaw control through differential thrust. This allows for simultaneous vertical takeoff and landing and agile all-attitude maneuverability without eliminating all traditional aerodynamic control surfaces. This innovative design not only significantly simplifies the mechanical structure and improves system reliability but also leverages the excellent aerodynamic characteristics of the blended wing-body structure to balance high-speed cruise capability and long-endurance performance, ultimately achieving a new aircraft design scheme that is structurally simplified, functionally comprehensive, and with optimized overall performance.

[0017] Furthermore, the aircraft also includes two winglets, which are respectively installed on the wingtips of the left and right wings and are symmetrical. The tips of the winglets extend upward and / or outward to suppress wingtip vortices and reduce the induced drag of the aircraft.

[0018] Furthermore, each ducted fan propulsion device includes: a ducted fan, a motor, and an electronic speed controller; the motor is electrically connected to the ducted fan to drive the ducted fan to rotate; the electronic speed controller is electrically connected to the motor and receives control commands from the ground control system to control the speed of the motor, thereby adjusting the thrust of the ducted fan.

[0019] Furthermore, the left and right wings are configured without wing control surfaces and without winglet control surfaces.

[0020] Furthermore, the aircraft also includes landing gear, which is respectively installed on the fuselage, left wing and right wing tail, for supporting and stabilizing the aircraft when it lands, so that it stands on the ground in a tail-seat take-off and landing configuration.

[0021] Furthermore, the body's skin is at least partially composed of solar photovoltaic materials.

[0022] According to another aspect of the present invention, the present invention also provides a control method for vertical takeoff of an aircraft, for flight control of the aircraft, the control method including a vertical takeoff phase, the vertical takeoff phase including: controlling the three ducted fan propulsion devices to provide vertical lift greater than or equal to the weight of the aircraft to maintain the hovering or vertical climb of the aircraft; and maintaining the attitude stability of the aircraft during the climb process by independently adjusting the thrust of the three ducted fan propulsion devices.

[0023] Furthermore, maintaining the attitude stability of the aircraft during the climb process includes: controlling the pitch attitude of the aircraft by adjusting the thrust of the main ducted fan propulsion device; controlling the yaw attitude of the aircraft by differentially adjusting the thrust of the left ducted fan propulsion device and the right ducted fan propulsion device; and controlling the roll attitude of the aircraft by coordinating the thrust of the left ducted fan propulsion device and the right ducted fan propulsion device.

[0024] Furthermore, the control method also includes a phase of transitioning from vertical takeoff to horizontal flight, which includes: by coordinating and regulating the thrust of the three ducted fan propulsion devices, the dominant direction of the resultant thrust is changed from vertically upward to horizontally forward; in this phase, the main lift source supporting the weight of the aircraft is switched from the thrust generated by the propellers of the three ducted fan propulsion devices to the aerodynamic lift generated by the blended wing-body structure at forward speed.

[0025] Furthermore, the transition from vertical takeoff to horizontal flight is achieved through the following steps: First, control the three ducted fan propulsion devices so that the resultant thrust they generate is vertically upward and greater than the aircraft's weight, in order to maintain the aircraft's vertical climb; Second, control the aircraft's attitude to tilt forward by increasing the thrust of the main ducted fan propulsion device and coordinating the reduction of the thrust of the left and right ducted fan propulsion devices, so that the direction of the resultant thrust is tilted forward, and its horizontal component serves as forward thrust to accelerate the aircraft, while its vertical component decreases accordingly; Third, when the aircraft's airspeed reaches a point where the aerodynamic lift generated by the blended wing-body structure is sufficient to support its weight, control the three ducted fan propulsion devices so that the resultant thrust they generate mainly contributes to the horizontal forward flight direction, in order to provide the forward thrust required for horizontal cruise.

[0026] According to another aspect of the present invention, the present invention also provides a control method for aircraft cruise, for flight control of the aircraft, the control method comprising a level flight cruise step: controlling the three ducted fan propulsion devices such that the resultant thrust generated by them is approximately horizontal and forward, and its magnitude is equal to the aerodynamic drag of the aircraft in cruise state; simultaneously, controlling the thrust of the left ducted fan propulsion device and the right ducted fan propulsion device to eliminate the unintended yaw and roll moments of the aircraft, and achieving pitch moment balance between the main ducted fan propulsion device, the left ducted fan propulsion device, and the right ducted fan propulsion device, thereby enabling the aircraft to maintain stable horizontal straight flight.

[0027] Furthermore, the control method also includes a yaw control step: when a change of course is required, the thrust of the left ducted fan propulsion device and the right ducted fan propulsion device is differentially adjusted to generate a yaw control torque around the vertical axis; wherein, when a left turn is required, the thrust of the right ducted fan propulsion device is controlled to be greater than the thrust of the left ducted fan propulsion device to generate a left yaw torque; when a right turn is required, the thrust of the left ducted fan propulsion device is controlled to be greater than the thrust of the right ducted fan propulsion device to generate a right yaw torque.

[0028] Furthermore, the control method also includes a pitch control step: when it is necessary to change the flight altitude, a pitch control torque around the lateral axis is generated by adjusting the thrust ratio of the main ducted fan propulsion device with the left and right ducted fan propulsion devices; wherein, when it is necessary to climb, the thrust of the left and right ducted fan propulsion devices is increased and / or the thrust of the main ducted fan propulsion device is decreased in a coordinated manner to generate a pitch torque that causes the nose to pitch up; when it is necessary to descend, the thrust of the main ducted fan propulsion device is increased and / or the thrust of the left and right ducted fan propulsion devices is decreased in a coordinated manner to generate a pitch torque that causes the nose to pitch down.

[0029] According to another aspect of the present invention, the present invention also provides a control method for vertical landing of an aircraft, for flight control of the aircraft, the control method including a transition phase from horizontal flight to vertical landing, the transition phase including: by coordinating and regulating the thrust of the three ducted fan propulsion devices and controlling the aircraft's attitude to pitch up, the effect of the resultant thrust on the aircraft changes from mainly providing horizontal forward thrust to mainly providing vertical lift; in this phase, the main lift source supporting the weight of the aircraft is switched from relying on the aerodynamic lift generated by the blended wing-body structure at forward speed to relying on the thruster lift generated by the three ducted fan propulsion devices.

[0030] Furthermore, the transition from horizontal flight to vertical landing is achieved through the following steps: First, the aircraft is controlled to transition from level flight to landing attitude. This is achieved by coordinating the increase in thrust of the main ducted fan propulsion unit and the decrease in thrust of the left and right ducted fan propulsion units, resulting in a positive pitch angle. The resultant thrust is tilted upwards and backwards, with its vertical component increasing to partially support the aircraft's weight, and its horizontal component shifting backwards to begin deceleration. Second, the thrust of the main ducted fan propulsion unit is continuously increased while the thrust of the left and right ducted fan propulsion units is decreased, causing the aircraft's pitch angle to continuously increase until it approaches vertical. The effect of the resultant thrust approaches vertical lift, and the forward velocity continuously decreases until it approaches zero. Third, when the aircraft enters a vertical hovering or slow descent state, the three ducted fan propulsion units are controlled so that their resultant thrust is directed vertically upwards. The descent rate is controlled by adjusting the thrust magnitude to achieve a smooth landing.

[0031] Furthermore, the control method also includes a vertical landing phase, which includes: controlling the three ducted fan propulsion devices to provide vertical lift less than the weight of the aircraft to achieve a controllable descent of the aircraft; and maintaining the attitude stability of the aircraft during descent and landing by independently adjusting the thrust of the three ducted fan propulsion devices.

[0032] Furthermore, maintaining the attitude stability of the aircraft during descent and landing includes: controlling the pitch attitude of the aircraft by adjusting the thrust of the main ducted fan propulsion device; controlling the yaw attitude of the aircraft by differentially adjusting the thrust of the left ducted fan propulsion device and the right ducted fan propulsion device; and controlling the roll attitude of the aircraft by coordinating the thrust of the left ducted fan propulsion device and the right ducted fan propulsion device.

[0033] The above-described technical solution of the present invention has the following beneficial technical effects: 1. Achieves a fusion of vertical takeoff and landing (VTOL) and high-efficiency cruise capabilities: This aircraft, with its three-ducted fan layout, combines the VTOL / STOVL capabilities of a multi-rotor aircraft with the high-speed, long-endurance cruise capabilities of a fixed-wing aircraft. Its unique blended wing-body design serves as the primary lifting body, providing extremely high aerodynamic efficiency during the cruise phase, making it particularly suitable for scenarios with long-term, high-efficiency requirements for wide-area monitoring (such as farmland and solar power plant inspections).

[0034] 2. Achieved structural simplification and improved reliability: By eliminating all mechanical control surfaces and adopting pure thrust vectoring for all-attitude control, the complexity, weight, and potential failure points associated with traditional control surfaces and their transmission mechanisms are fundamentally eliminated. This not only significantly reduces manufacturing costs and maintenance difficulty but also greatly improves the aircraft's reliability and survivability, providing assurance for sustained missions in complex or remote environments.

[0035] 3. The flight performance and energy efficiency of the entire mission profile have been optimized: (1) High-speed performance: Thanks to the low wind resistance of the ducted fan and the efficient aerodynamic shape of the whole aircraft, the aircraft has the ability to sprint at high speed for a short time when needed (such as a maximum Mach number of 0.7), which expands the mission flexibility; (2) Long-endurance performance: The low-drag aerodynamic layout and efficient thrust distribution strategy minimize the energy loss during flight, laying a solid foundation for achieving long-term, low-power continuous flight.

[0036] 4. Provides smooth and stable full-mode flight control: The accompanying control methods provide clear and coordinated control logic for the aircraft throughout the entire phase of vertical takeoff, transition, cruise, re-transition, and vertical landing. By precisely allocating the thrust of the three ducts, smooth and stable transitions between flight modes and stable attitude control throughout the entire flight are achieved, ensuring flight safety and mission reliability.

[0037] In summary, through systematic and innovative design, this invention successfully integrates and optimizes multiple previously contradictory or difficult-to-coordinate performance indicators on a single flight platform, ultimately achieving a new type of aircraft solution that is structurally simplified, fully functional, has a long flight time, high speed, and high reliability, greatly expanding its application potential in fields such as wide-area monitoring and emergency patrol. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the dimensions of a half-wing of an aircraft according to an embodiment of the present invention; Figure 2 This is a front view of an aircraft according to an embodiment of the present invention; Figure 3 This is a side view of an aircraft according to an embodiment of the present invention; Figure 4 This is a graph showing the relationship between the range of the aircraft and the number of different types of ducted fans in a specific embodiment of the present invention; Figure 5 This is a disassembly diagram of a ducted fan propulsion device in a specific embodiment of the present invention; Figure 6 This is a schematic diagram of an aircraft transitioning from a vertical takeoff state to a horizontal flight state in an embodiment of the present invention; Figure 7 This is a schematic diagram of multiple flight states of an aircraft in an embodiment of the present invention; Figure 8 This is a flight cross-sectional view of an aircraft according to a specific embodiment of the present invention; Figure 9 This is a lift-drag characteristic diagram of an aircraft in a specific embodiment of the present invention.

[0039] Figure label: 1: Right wing; 2: Main ducted fan propulsion system; 3: Left wing; 4: Left ducted fan propulsion system; 5: Right ducted fan propulsion system; 6: Landing rack; 7: Fuselage; 8: Winglets; 9: Symmetrical airfoil support; L1: Vertical distance from the longitudinal section of the main ducted fan center to the longitudinal section of the aircraft's center of gravity; L2: Vertical distance from the longitudinal section of the left or right ducted fan center to the longitudinal section of the aircraft's center of gravity; L3: Horizontal distance from the longitudinal section of the main ducted fan center to the longitudinal section of the aircraft's center of gravity; L4: Horizontal distance from the longitudinal section of the left or right ducted fan center to the longitudinal section of the aircraft's center of gravity; L5: Horizontal distance from the longitudinal section of the right ducted fan center to the longitudinal section of the aircraft's center of gravity; L6: Horizontal distance from the longitudinal section of the left ducted fan center to the longitudinal section of the aircraft's center of gravity. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0041] The following is combined with Figures 1 to 9 The present invention will describe the aircraft and its control method provided by the present invention.

[0042] Figure 1 This is a schematic diagram of the wing dimensions of an aircraft in a specific embodiment of the present invention.

[0043] The following is combined with Figure 1 The following further details the relevant dimensions of the blended wing-body aircraft provided by this invention: In some embodiments, a blended wing-body aircraft includes a fuselage, a left wing, and a right wing. The total wingspan of the aircraft is S. The lengths of the fuselage, wing root, and wingtip satisfy the following conditions with respect to the total wingspan: the fuselage length L satisfies: 0.4S≤L≤0.6S; the wing root chord length Lr at the end of the left and right wings connected to the fuselage satisfies: 0.2S≤Lr≤0.4S; the wingtip chord length Lt at the end of the left and right wings away from the fuselage satisfies: 0.1S≤Lt≤0.2S; the total wingspan S of the aircraft ranges from 0.5 to 10 m; and both the left and right wings have a sweep angle of 30° to 60°.

[0044] In a specific implementation, the aircraft is designed according to the given detailed dimensions, with the following core geometric parameters: wingspan S is 1.3m, and overall fuselage length L is 0.695m. The wing section adopts a swept-back design with a sweep angle of 45°. The root chord length Lr is 0.385m, and the wingtip chord length Lt is 0.12m, resulting in a total wing area of ​​0.45m². 2 For specific dimensions, please refer to Table 1 below.

[0045]

[0046] Table 1 Figure 2 This is a front view of an aircraft according to an embodiment of the present invention.

[0047] like Figure 2 As shown, in some embodiments, the blended wing-body aircraft provided by the present invention further includes: a main ducted fan propulsion device 2, located above the tail of the fuselage 7; a left ducted fan propulsion device 4 and a right ducted fan propulsion device 5, respectively symmetrically located below the left wing 3 and the right wing 1; the three propulsion devices receive control commands from the ground control system or the onboard control system to collaboratively complete the aircraft's vertical takeoff and landing, pitch, yaw, and cruise control; the onboard control system is electrically connected to the main ducted fan propulsion device 2, the left ducted fan propulsion device 4, and the right ducted fan propulsion device 5, and is used to control the thrust of the three propulsion devices to collaboratively complete the aircraft's vertical takeoff and landing, pitch, and yaw control. Based on this aircraft power layout, the aircraft can efficiently and stably achieve full attitude control under conditions such as vertical takeoff and landing and high-speed forward flight to complete complex flight missions, thereby demonstrating excellent mission execution capabilities.

[0048] In one specific embodiment, reference is made to Figure 2The aircraft includes a fuselage 7, three ducted fan propulsion units, an onboard control system, two winglets 8, and two symmetrical left and right wings 3 and 1. The left and right wings 3 and 1 provide aerodynamic lift during level flight. The three ducted fan propulsion units include a main ducted fan propulsion unit 2, a left ducted fan propulsion unit 4, and a right ducted fan propulsion unit 5. The control system is electrically connected to the three ducted fan propulsion units and controls them. The main ducted fan propulsion unit 2 is mounted on the upper part of the tail of the fuselage 7 via a bracket. It generates forward thrust and, under the control of the control system, completes the aircraft's vertical takeoff and landing and pitch adjustment. The left and right ducted fan propulsion units 4 and 5... The thrust device 5 is installed below the left wing 3 and the right wing 1 respectively via symmetrical airfoil brackets 9. It generates thrust and, under the control of the ground control system and / or the onboard control system, completes the vertical take-off and landing and the adjustment of the left and right yaw direction of the aircraft. The airfoil design of the symmetrical airfoil bracket 9 itself can generate small aerodynamic drag and may even generate a certain amount of lift, thereby minimizing the negative impact on flight performance. The two winglets 8 are installed on the wingtips of the left wing 3 and the right wing 1 respectively, and are symmetrical. The tips of the winglets 8 extend upward and / or outward, which can effectively suppress the generation of wingtip vortices, thereby significantly reducing induced drag, improving the aerodynamic efficiency of the UAV, and thus increasing its range and endurance.

[0049] In some embodiments, the aircraft adopts a controlless configuration (zero-control design). Specifically, the controlless configuration means that there are no mechanical control surfaces on the fuselage 7 for flight control, and the left wing 3 and right wing 1 are formed without wing control surfaces and winglet control surfaces. The pitch and yaw control of the aircraft is achieved entirely through thrust distribution by the control system. The controlless configuration makes the fuselage surface smooth and continuous, fundamentally eliminating parasitic drag caused by control surface gaps and deflection, and significantly improving aerodynamic efficiency. To achieve flight control in a controlless configuration, the control system is also used to achieve zero-control flight of the aircraft and serves as the sole execution source for pitch, roll, and yaw attitude control. It differentially controls the thrust output of the three ducted fan propulsion devices to directly generate and control all attitude control torques acting on the aircraft body. Through differential control of the aircraft's power system, direct, agile, and powerful control torques can be generated, especially at low speeds and in hovering states, where its control efficiency is far higher than that of aerodynamic control surfaces that rely on airflow.

[0050] In some embodiments, the fuselage 7 adopts an advanced blended wing-body configuration, eliminating the distinction between the intermediate fuselage and wings. The blended wing-body directly constitutes the aircraft's main lifting surface, maximizing lift generation, significantly improving the overall aerodynamic efficiency of the aircraft, and exhibiting a high lift-to-drag ratio. When the aircraft needs to perform high-speed missions, its low drag enables short-duration high-speed flight capability; simulation calculations show that the maximum speed can reach Mach 0.7.

[0051] In some embodiments, the skin of the aircraft is at least partially made of solar photovoltaic material, and the electrical energy generated therefrom is delivered to the onboard battery or power system, which can continuously convert abundant solar energy into the electrical energy required for the drone's flight, thereby effectively compensating for battery consumption and significantly extending the drone's endurance and operating radius.

[0052] Figure 3 This is a side view of an aircraft according to an embodiment of the present invention.

[0053] like Figure 3 As shown, in some embodiments, the aircraft also includes three landing supports 6, which are respectively installed at the tail of the fuselage 7, the left wing 3 and the right wing 1, to support and stabilize the aircraft during landing, so that it stands on the ground in a tail-seat take-off and landing configuration.

[0054] Combination Figure 2 and Figure 3 In one specific embodiment, the main ducted fan propulsion device 2 is located directly above the fuselage 7 and is mounted on the landing rack 6 at the tail of the fuselage 7. The left ducted fan propulsion device 4 and the right ducted fan propulsion device 5 are symmetrically distributed below the fuselage 7 or below the wings on both sides. The left ducted fan propulsion device 4 and the right ducted fan propulsion device 5 are fixed to the fuselage 7 by symmetrical airfoil brackets 9. There are three landing racks 6 at the tail of the fuselage 7. The three landing racks 6 are non-retractable fixed structures, and the rear ends of the three landing racks 6 are flush, so that the UAV can stand on the ground in a tail-sitting take-off and landing state.

[0055] Figure 4 This is a graph showing the relationship between the range of the aircraft and the number of different types of ducted fans in a specific embodiment of the present invention.

[0056] The aircraft power layout provided by this invention adopts a three-ducted fan propulsion device, which is derived through the formulas of aircraft weight and range. The three ducted fans are the optimal solution obtained under the joint constraints of the weight and range formulas.

[0057] Assuming the aircraft's cruising speed is V, then the range is:

[0058] Where n is the number of fans, Q is the battery capacity, D is the drag of the aircraft during constant-speed level flight, and S L S D For the characteristic area, C D C is the overall drag coefficient of the aircraft. LLet be the overall lift coefficient, and k1 and b1 be the thrust-current curve parameters of the ducted fan. Considering that the battery voltage will drop after a period of time, failing to meet the fan's operating requirements, it's impossible for the fan to operate continuously until the battery is depleted. Furthermore, the fan's thrust-current curve is not perfectly linear; therefore, a redundancy factor R is added to reflect its difference from actual conditions. The final formulas for flight time and range are:

[0059] After obtaining the range and flight time equations, the power layout of the aircraft can be selected and optimized based on these equations. Analysis of the range equations shows that when selecting the fan model, the slope of the operating current-fan thrust curve should be as large as possible, the fan weight should be as light as possible, and the fan thrust should also meet the thrust requirements of the vertical takeoff and landing aircraft.

[0060] Its objective function and constraint equations are as follows, where W is the gravity of the aircraft, and T... max T represents the maximum thrust of the culvert fan. min Indicates the minimum thrust of the culvert fan:

[0061] like Figure 4 As shown, in one specific embodiment, simulation calculations and comparisons of commonly available ducted fans reveal the relationship between different ducted fan models and their quantities, and thus the aircraft's range. From... Figure 4 The results show that when the number of fans is 3 and the fans are model QF2611 4000kv, the aircraft's range reaches its maximum of 40.8km.

[0062] See Figure 4 , combined Figure 2 and Figure 3To ensure control stability, the aircraft adopts a three-point configuration. In another specific embodiment, all three ducted fans are selected from the same model, namely QF2611 4000kV ducted fans. The main ducted fan propulsion unit 2 is located at the center of the upper half of the fuselage 7, generating thrust F2. The left ducted fan propulsion unit 4 and the right ducted fan propulsion unit 5 are located under the wing, generating thrust F4 and F5 respectively. The vertical distance L1 from the center longitudinal section of the main ducted fan to the longitudinal section of the aircraft's center of gravity is 132mm. The vertical distance L2 from the center longitudinal section of the left or right ducted fan to the longitudinal section of the aircraft's center of gravity is 80mm. The horizontal distance L3 from the center longitudinal section of the main ducted fan to the longitudinal section of the aircraft's center of gravity is 257mm. The horizontal distance L4 from the center longitudinal section of the left or right ducted fan to the longitudinal section of the aircraft's center of gravity is 50mm. The horizontal distance L5 from the center longitudinal section of the right ducted fan to the longitudinal section of the aircraft's center of gravity is equal to the horizontal distance L6 from the center longitudinal section of the left ducted fan to the longitudinal section of the aircraft's center of gravity, which is 300mm.

[0063] Figure 5 This is a disassembly diagram of a ducted fan propulsion device in a specific embodiment of the present invention.

[0064] like Figure 5 As shown, in some embodiments, each ducted fan propulsion device includes: a ducted fan, a motor, an electronic speed controller, a signal receiver, and a battery pack. The electronic speed controller communicates with the control system through the signal receiver to receive control commands. The motor is integrated with and electrically connected to the ducted fan to drive the ducted fan to rotate. The motor is located at the rear end of the ducted fan. The electronic speed controller is electrically connected to the motor and receives control commands from the ground control system to control the motor speed, thereby adjusting the thrust of the ducted fan. The battery pack is electrically connected to the electronic speed controller.

[0065] See Figure 5 In one specific embodiment, the three ducted fan propulsion units are all ducted fan engines of the same model, specifically the QF2611 4000kV, with a total maximum power of 1652.4W and a maximum thrust of 27.9N. The motors are connected to the electronic speed controller (ESC) via banana plug connectors to ensure efficient power management and control. The high thrust-to-weight ratio of the propulsion system enables the UAV to easily perform vertical takeoff and landing operations.

[0066] Figure 6 This is a schematic diagram illustrating the transition of an aircraft from a vertical takeoff state to a horizontal flight state according to an embodiment of the present invention. The following is in conjunction with... Figure 6 The control method for the aircraft provided by this invention will be further explained below: In some embodiments, the present invention also provides a control method for vertical takeoff of an aircraft, used to control the vertical takeoff process of an aircraft. This control method includes a vertical takeoff phase, which specifically includes the following: controlling three ducted fan propulsion devices to provide vertical lift greater than or equal to the weight of the aircraft to maintain hovering or vertical climb; and maintaining attitude stability of the aircraft during climb by independently adjusting the thrust of the three ducted fan propulsion devices. Maintaining attitude stability of the aircraft during climb includes: controlling the pitch attitude of the aircraft by adjusting the thrust of the main ducted fan propulsion device 2; controlling the yaw attitude of the aircraft by differentially adjusting the thrust of the left ducted fan propulsion device 4 and the right ducted fan propulsion device 5; and controlling the roll attitude of the aircraft by coordinating the thrust of the left ducted fan propulsion device 4 and the right ducted fan propulsion device 5.

[0067] In some embodiments, the control method for vertical takeoff of the aircraft further includes a phase of transitioning from vertical takeoff to horizontal flight, which specifically includes: by coordinating and regulating the thrust of the three ducted fan propulsion devices, changing the dominant direction of the resultant thrust from vertically upward to horizontally forward; in this phase, the main lift source supporting the weight of the aircraft is switched from the thrust generated by the three ducted fan propulsion devices to the aerodynamic lift generated by the blended wing-body structure at forward speed. The transition from vertical takeoff to horizontal flight is achieved through the following steps: First, control the three ducted fan propulsion devices so that the resultant thrust generated is vertically upward and greater than the aircraft's weight to maintain the aircraft's vertical climb; Second, control the aircraft's attitude to tilt forward by increasing the thrust of the main ducted fan propulsion device 2 and coordinating the reduction of the thrust of the left ducted fan propulsion device 4 and the right ducted fan propulsion device 5, so that the direction of the resultant thrust is tilted forward, and its horizontal component serves as forward thrust to accelerate the aircraft, while its vertical component decreases accordingly; Third, when the aircraft's airspeed reaches a point where the aerodynamic lift generated by the blended wing-body structure is sufficient to support its weight, control the three ducted fan propulsion devices so that the resultant thrust generated mainly contributes to the horizontal forward flight direction to provide the forward thrust required for horizontal cruise. In some embodiments, the control system is used to control the aircraft to transition from a vertical takeoff state to a horizontal flight state. During the transition, the control system performs the following operations: a. In the first stage, the three ducted fan propulsion devices are mainly controlled to provide vertical lift to maintain hovering or vertical climb; b. In the second stage, the aircraft is controlled to tilt forward and accelerate. During this process, the thrust of the three ducted fan propulsion devices is adjusted to coordinately increase the forward thrust of the aircraft and decrease the vertical lift, so that the pitch angle of the aircraft is continuously reduced to horizontal; c. In the third stage, when the airspeed of the aircraft reaches a predetermined value, the aerodynamic lift generated by the wings is sufficient to become the main lift source supporting the weight of the aircraft, and the three ducted fan propulsion devices are controlled to mainly provide horizontal forward thrust.

[0068] In some embodiments, the present invention also provides a control method for vertical landing of an aircraft, for controlling the vertical landing process of an aircraft. The control method includes a phase of transitioning from horizontal flight to vertical landing. This phase includes: coordinating and regulating the thrust of the three ducted fan propulsion devices and controlling the aircraft's attitude to pitch up, so that the effect of the resultant thrust on the aircraft changes from primarily providing horizontal forward thrust to primarily providing vertical lift. In this phase, the main lift source supporting the weight of the aircraft is switched from relying on the aerodynamic lift generated by the blended wing-body structure at forward speed to relying on the thruster lift generated by the three ducted fan propulsion devices. The transition from level flight to vertical landing is achieved through the following steps: First, the aircraft is controlled to transition from level flight to landing attitude. This is achieved by coordinating the increase in thrust of the main ducted fan propulsion unit 2 and the decrease in thrust of the left ducted fan propulsion unit 4 and the right ducted fan propulsion unit 5, resulting in a positive pitch angle. The resultant thrust is tilted upwards and backwards, with its vertical component increasing to partially support the aircraft's weight, and its horizontal component shifting backwards to begin deceleration. Second, the thrust of the main ducted fan propulsion unit 2 is continuously increased while the thrust of the left ducted fan propulsion unit 4 and the right ducted fan propulsion unit 5 is decreased, causing the aircraft's pitch angle to continuously increase until it approaches vertical. The effect of the resultant thrust approaches vertical lift, and the forward velocity continuously decreases until it approaches zero. Third, when the aircraft enters a vertical hovering or slow descent state, the three ducted fan propulsion units are controlled so that their resultant thrust is directed vertically upwards. The descent rate is controlled by adjusting the thrust magnitude to achieve a smooth landing.

[0069] In some embodiments, the control method for vertical landing of the aircraft further includes a vertical landing phase, which includes: controlling the three ducted fan propulsion units to provide vertical lift less than the weight of the aircraft to achieve a controllable descent; and maintaining the attitude stability of the aircraft during descent and landing by independently adjusting the thrust of the three ducted fan propulsion units. Maintaining the attitude stability of the aircraft during descent and landing includes: controlling the pitch attitude of the aircraft by adjusting the thrust of the main ducted fan propulsion unit 2; controlling the yaw attitude of the aircraft by differentially adjusting the thrust of the left ducted fan propulsion unit 4 and the right ducted fan propulsion unit 5; and controlling the roll attitude of the aircraft by coordinating the thrust of the left ducted fan propulsion unit 4 and the right ducted fan propulsion unit 5.

[0070] In some embodiments, the control system is used to control the aircraft to transition from a horizontal flight state to a vertical landing state (and...). Figure 6(The flight state changes shown are reversed). During the transition, the control system performs the following operations: a. In the first stage, it reduces forward thrust, controls the aircraft attitude to pitch up to increase the angle of attack and decelerate, and simultaneously activates one or more ducted fan propulsion units to provide some vertical lift; b. In the second stage, as the airspeed further decreases, it coordinately increases the output ratio of vertical lift to compensate for the wing lift lost due to the decrease in airspeed, and controls the aircraft attitude to gradually tend towards verticality; c. In the third stage, when the airspeed is below the effective control limit, it controls the three ducted fan propulsion units to provide full vertical lift for hovering or vertical landing.

[0071] In some embodiments, the present invention also provides a control method for aircraft cruise, used to control the cruise process of an aircraft. The control method includes a level flight cruise step: controlling three ducted fan propulsion devices so that the resultant thrust generated by them is approximately horizontal and forward, and its magnitude is equal to the aerodynamic drag of the aircraft in the cruise state; simultaneously, controlling the thrust of the left ducted fan propulsion device 4 and the right ducted fan propulsion device 5 to eliminate the unexpected yaw and roll moments of the aircraft, and achieving pitch moment balance between the main ducted fan propulsion device 2 and the left ducted fan propulsion device 4 and the right ducted fan propulsion device 5, thereby enabling the aircraft to maintain stable horizontal straight flight.

[0072] In some embodiments, the control method for aircraft cruise further includes a yaw control step: when a change in heading is required, the thrust of the left ducted fan propulsion device 4 and the right ducted fan propulsion device 5 is differentially adjusted to generate a yaw control torque about the vertical axis; wherein, when a left turn is required, the thrust of the right ducted fan propulsion device 5 is controlled to be greater than the thrust of the left ducted fan propulsion device 4 to generate a left yaw torque; when a right turn is required, the thrust of the left ducted fan propulsion device 4 is controlled to be greater than the thrust of the right ducted fan propulsion device 5 to generate a right yaw torque.

[0073] In some embodiments, the aircraft cruise control method further includes a pitch control step: when it is necessary to change the flight altitude, a pitch control torque about the horizontal axis is generated by adjusting the thrust ratio of the main ducted fan propulsion device 2 with the left ducted fan propulsion device 4 and the right ducted fan propulsion device 5; wherein, when it is necessary to climb, the thrust of the left ducted fan propulsion device 4 and the right ducted fan propulsion device 5 is increased in coordination and / or the thrust of the main ducted fan propulsion device 2 is decreased, generating a pitch torque that causes the nose to pitch up; when it is necessary to descend, the thrust of the main ducted fan propulsion device 2 is increased in coordination and / or the thrust of the left ducted fan propulsion device 4 and the right ducted fan propulsion device 5 is decreased, generating a pitch torque that causes the nose to pitch down.

[0074] See Figure 6 , combined Figure 3, in some specific embodiments, the thrust of the main duct fan is T2, the thrust of the left duct fan is T4, the thrust of the right duct fan is T5, the gravity of the aircraft is W, the vertical distance L1 from the central longitudinal section of the main duct fan to the central longitudinal section of the aircraft's center of gravity, and the vertical distance L2 from the central longitudinal section of the left or right duct fan to the central longitudinal section of the aircraft's center of gravity. The flight process of the aircraft can be divided into three stages: (1) The vertical takeoff and landing stage of the aircraft: T2 + T4 + T5 > W, and at the same time T4 = T5, T4 · L2+T5 · L2=T2 · L1, ensuring stable and balanced attitude during the vertical takeoff and landing stage.

[0075] (2) The stage of the aircraft transitioning from vertical takeoff to horizontal flight: Adjust the thrust T2 of the main duct fan to increase its thrust. Keep the thrusts T4 of the left duct fan and T5 of the right duct fan unchanged, and T4 = T5. During this stage, T4 · L2 + T5 · L2 < T2 · L1, causing the aircraft to generate a pitching moment and transition from the vertical takeoff state to a large angle of attack state. Next, gradually reduce the thrust T2 of the main duct fan while still keeping the thrusts T4 of the left duct fan and T5 of the right duct fan unchanged. The pitching moment causes the angle of attack of the aircraft to decrease and the angular acceleration to decrease to 0. While keeping the thrusts T4 of the left duct fan and T5 of the right duct fan unchanged, reduce the thrust T2 of the main duct fan on the back to make the aircraft generate a negative pitching moment, T4 · L2 + T5 · L2 > T2 · L1. During this process, the angle of attack decreases to 0 degrees and the angular acceleration is negative. After the flight attitude becomes horizontal, reduce the thrust T2 of the main duct fan on the back and reduce the thrusts T4 of the left duct fan and T5 of the right duct fan, such that: T4 · L2 + T5 · L2 = T2 · L1, maintaining the aircraft in level flight.

[0076] (3) The stage of the aircraft transitioning from level flight to vertical descent: Opposite to stage (2), the aircraft first increases the thrusts T4 of the left duct fan and T5 of the right duct fan while keeping T2 unchanged, causing the aircraft to generate a pitching moment, and then gradually increases T2 such that T4 · L2 + T5 · L2 < T2 · L1. When the flight attitude approaches vertical, appropriately reduce T2 such that T4 · L2 + T5 · L2 = T2 · L1, and at the same time T4 + T5 + T2 is slightly less than W, causing the aircraft to slowly descend vertically and finally land smoothly on the ground.

[0077] In addition, when a left turn is required, only the thrust T5 of the right ducted fan needs to be appropriately increased, i.e., T5 > T4, to generate a left yaw moment and achieve a left turn of the aircraft; when a right turn is required, only the thrust T4 of the left ducted fan needs to be appropriately increased, i.e., T4 > T5, to generate a right yaw moment and achieve a right turn of the aircraft. When a climb is required, the thrust T4 of the left ducted fan and the thrust T5 of the right ducted fan are increased simultaneously, such that T4·L2 + T5·L2 > T2·L1, to generate a positive pitch moment and the aircraft climbs. When a descent is required, the thrust T2 of the main ducted fan is increased, such that T4·L2 + T5·L2 < T2·L1, to generate a negative pitch moment and the aircraft descends.

[0078] Figure 7 It is a schematic diagram of various flight states of an aircraft in an embodiment of the present invention.

[0079] Refer to Figure 7 , in combination with Figure 6 , in a specific embodiment, three ducted fans of the aircraft are all selected as fans of model QF2611 4000kv, and the specific operation process of the aircraft can be divided into four states: State 1, vertical take-off stage: The aircraft starts to take off from a stationary position where the body is parked vertically, and the three ducted fan propulsion devices all reach the maximum thrust. The main ducted fan propulsion device 2, the left ducted fan propulsion device 4, and the right ducted fan propulsion device 5 all operate with a thrust of about 9.3 N. The total thrust of the three ducted fan propulsion devices is greater than the gravity of the aircraft, enabling the aircraft to take off vertically and stably. During the climb stage, the output of a single ducted fan propulsion device is continuously fine-tuned to compensate for atmospheric disturbances and maintain precise attitude control throughout the climb stage.

[0080] State 2, Transition from Vertical Takeoff to Horizontal Flight: When the aircraft reaches a sufficient altitude (e.g., 55m above the ground), it begins the transition to horizontal flight through coordinated thrust modulation. The main ducted fan propulsion unit 2 gradually increases its thrust output, while the lift ducted fan propulsion units (left ducted fan propulsion unit 4 and right ducted fan propulsion unit 5) symmetrically decrease their thrust, creating a controllable thrust differential that generates a pitching moment, causing the aircraft's attitude to change from vertical to horizontal, forming an upward arc-shaped flight path. During this process, the aircraft maintains a positive climb rate while maintaining a certain airspeed, allowing the wings (right wing 1 and left wing 3) to generate sufficient aerodynamic lift. Throughout the transition, the three ducted fan propulsion units remain active at different power levels, providing the necessary stabilizing thrust when the aircraft reorients itself to a horizontal flight attitude. When the thrust of the main ducted fan propulsion device 2 is 9.3N, and the thrust of the left ducted fan propulsion device 4 and the right ducted fan propulsion device 5 is 3.1N, the pitch moment of the aircraft is 0.43N·m, the moment of inertia of the aircraft along the horizontal axis is 0.021kg / m2, and the angular acceleration is 20.476rad / s, the pitch state of the aircraft changes.

[0081] State 3, Cruise and Direction Control: During level flight, all three ducted fan propulsion units are kept operational, and their thrust is adjusted. When turning right, the thrust of the left ducted fan propulsion unit 4 is increased, while the thrust output of the right ducted fan propulsion unit 5 is decreased, while the thrust of the main ducted fan propulsion unit 2 remains constant. This generates a controllable yaw moment, causing the aircraft to turn right. Correspondingly, the thrust output of the right ducted fan propulsion unit 5 is increased, while the thrust of the left ducted fan propulsion unit 4 is decreased, while the main ducted fan propulsion unit 2 maintains a power of 500W, achieving a left turn. Climb and descent maneuvers are achieved by simultaneously adjusting the symmetrical power of the left and right ducted fan propulsion units. During climb, the thrust of the left ducted fan propulsion unit 4 and the right ducted fan propulsion unit 5 is increased; during descent, the thrust of the left ducted fan propulsion unit 4 and the right ducted fan propulsion unit 5 is decreased.

[0082] State 4, Landing Approach and Vertical Descent: During the landing phase, the aircraft begins landing by gradually rebalancing the thrust of the ducted fan propulsion systems—increasing the thrust output of the left and right ducted fan propulsion systems (4 and 4) while reducing the power of the main ducted fan propulsion system (2) to transition back to vertical flight. As forward airspeed decreases, the power of the three ducted fan propulsion systems needs to be continuously adjusted to achieve stable hovering characteristics. During the final descent, the three ducted fan propulsion systems work together, with the total thrust less than the fuselage weight, descending slowly while fine-tuning the output power of the three ducted fan propulsion systems to maintain a controlled descent rate. At the end of the landing sequence, the landing support (6) contacts the landing surface, and the power is reduced to idle speed, achieving vertical recovery.

[0083] Figure 8 This is a flight cross-sectional view of an aircraft in a specific embodiment of the present invention.

[0084] like Figure 8 As shown, a typical mission of an aircraft includes five key stages: vertical takeoff, tilting the fuselage, horizontal flight, tilting the fuselage again, and vertical landing. Figure 8 Based on the specific data provided in Table 2, the basic workflow of an aircraft from takeoff to landing is clearly illustrated: (1) Vertical take-off phase: The aircraft rises vertically from the ground (0m) to a height of 50m, during which the horizontal speed remains at 0.

[0085] (2) First tilting phase: During the climb from 50 to 55 m, the aircraft begins to tilt in preparation for transitioning to level flight.

[0086] (3) Horizontal flight phase: At a cruising altitude of 55m, the aircraft first accelerates to a cruising speed of 20m / s, maintains this speed to perform the mission, and finally decelerates.

[0087] (4) Second tilting phase: During the descent from 55 to 50 meters, the aircraft tilts again to adjust its attitude and prepare for vertical landing.

[0088] (5) Vertical descent phase: descend from a height of 50m to the ground (0m) and ensure that the horizontal speed is zero to achieve a smooth landing.

[0089]

[0090] Table 2 Figure 9 This is a lift-drag characteristic diagram of an aircraft in a specific embodiment of the present invention.

[0091] like Figure 9As shown, the aircraft exhibits excellent aerodynamic efficiency, with a smooth lift-drag characteristic curve and good performance at different angles of attack.

[0092] In one specific embodiment, the aircraft uses the NACA M6 high-speed airfoil as its airfoil profile. This airfoil is renowned for its low drag and good lift characteristics across the transonic range. Based on this airfoil, precise aerodynamic simulation calculations were performed on the full-scale aircraft model to obtain... Figure 9 The curves showing the relationship between lift-to-drag ratio and key characteristics such as angle of attack are presented. These data not only confirm the high lift-to-drag ratio advantage of the blended wing-body airframe as the main lifting surface, but also provide crucial evidence for the performance matching and optimization of aircraft in various modes such as vertical takeoff and landing and high-speed cruise.

[0093] In some embodiments, the aircraft is a fixed-wing aircraft with vertical takeoff and landing (VTOL) capabilities. It achieves the VTOL characteristics of a multi-rotor aircraft through a three-ducted fan propulsion system, while relying entirely on its fixed wings to generate aerodynamic lift during horizontal flight. This design combines the high-efficiency cruise advantages of a fixed-wing configuration with the takeoff and landing flexibility of a multi-rotor configuration. This integrated design, through a zero-control-surface layout and thrust vectoring control, significantly improves aerodynamic efficiency and mission adaptability while maintaining the high-speed performance of a fixed-wing aircraft.

[0094] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects. For example, A and / or B indicates that there can be three relationships: A alone, A and B simultaneously, and B alone. Another example is A and / or B and / or C, which indicates that there can be eight relationships: A alone, B alone, C alone, A and B simultaneously, A and C simultaneously, B and C simultaneously, A, B, and C simultaneously, and A, B, and C simultaneously not existing. Furthermore, the character " / " in this article indicates that the preceding and following related objects have an "or" relationship.

[0095] In the embodiments of this application, "multiple" refers to two or more kinds, and "more than" refers to two or more kinds.

[0096] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A blended wing body aircraft comprising a fuselage, a left wing and a right wing, characterised in that : The total wingspan length of the aircraft is S; The length L of the fuselage satisfies: 0.4S≤L≤0.6S; The wing root chord length Lr of the left wing and the right wing at the end connected with the fuselage satisfies: 0.2S≤Lr≤0.4S; The wing tip chord length Lt of the left wing and the right wing at the end away from the fuselage satisfies: 0.1S≤Lt≤0.2S.

2. The aircraft of claim 1, wherein, The total wingspan length S of the aircraft ranges from 0.5m to 10m; the left wing and the right wing each have a back-sweep angle of 30° to 60°.

3. The aircraft of claim 1 or 2, wherein, Further comprising: A main ducted fan propulsion device arranged above the tail of the fuselage; A left ducted fan propulsion device and a right ducted fan propulsion device symmetrically arranged below the left wing and the right wing respectively; The three propulsion devices receive control instructions from a ground control system or an on-board control system to cooperatively complete the vertical take-off and landing, pitch, yaw and cruising control of the aircraft.

4. The aircraft of any one of claims 1-3, wherein, Further comprising: An on-board control system electrically connected with the main ducted fan propulsion device, the left ducted fan propulsion device and the right ducted fan propulsion device, for controlling the thrust of the three propulsion devices to cooperatively complete the vertical take-off and landing, pitch and yaw control of the aircraft.

5. The aircraft of any one of claims 1-4, wherein, Further comprising two wing tip winglets, which are respectively installed on the left wing tip and the right wing tip and are left-right symmetrical, with the end of the winglet extending upward and / or outward to suppress wing tip vortex and reduce the induced drag of the aircraft.

6. The aircraft of any one of claims 3-5, wherein, Each ducted fan propulsion device comprises a ducted fan, a motor and an electronic speed regulator; The motor is electrically connected with the ducted fan to drive the rotation of the ducted fan; The electronic speed regulator is electrically connected with the motor to receive control instructions from the ground control system to control the rotation speed of the motor, thereby adjusting the thrust of the ducted fan.

7. The aircraft of any one of claims 1 to 6, wherein, The left wing and the right wing are formed as ailerons without winglets.

8. The aircraft of any one of claims 1 to 7, wherein, Further comprising landing supports arranged at the tail of the fuselage, the left wing and the right wing respectively, for supporting and stabilizing the parked aircraft when the aircraft lands, thereby standing on the ground in a tail-sitting take-off and landing state.

9. The aircraft of any one of claims 1 to 8, wherein, The skin of the fuselage is at least partially composed of solar photovoltaic material.

10. A control method for vertical takeoff of an aircraft, for flight control of the aircraft according to claims 1-9, characterized by, The control method comprises a vertical take-off phase, which comprises: Controlling the three ducted fan propulsion devices to provide vertical lift greater than or equal to the weight of the aircraft to maintain hovering or vertical climb of the aircraft; By independently adjusting the thrust of the three ducted fan propulsion devices, the attitude stability of the aircraft during climbing is maintained.

11. The control method according to claim 10, wherein The maintaining of the attitude stability of the aircraft during climbing comprises: Controlling the pitch attitude of the aircraft by adjusting the thrust of the main ducted fan propulsion device; Controlling the yaw attitude of the aircraft by differentially adjusting the thrust of the left ducted fan propulsion device and the right ducted fan propulsion device; Controlling the roll attitude of the aircraft by cooperatively adjusting the thrust of the left ducted fan propulsion device and the right ducted fan propulsion device.

12. The control method according to claim 10, wherein The control method further comprises a phase of transitioning from vertical take-off to horizontal flight, which comprises: By coordinating the thrust of the three ducted fan propulsion units, the dominant direction of the resultant thrust is changed from vertical up to horizontal forward; In this phase, the main source of lift to support the weight of the aircraft is switched from the lift generated by the three ducted fan propulsion units to the aerodynamic lift generated by the blended wing body structure at forward speed.

13. The control method according to claim 12, wherein The phase of transition from vertical take-off to horizontal flight is achieved by the following steps: Step 1, control the three ducted fan propulsion units to generate a resultant thrust vertically upward and greater than the weight of the aircraft to maintain the vertical climb of the aircraft; Step 2, control the aircraft to pitch forward, by increasing the thrust of the main ducted fan propulsion unit and coordinating to decrease the thrust of the left and right ducted fan propulsion units, the direction of the resultant thrust is tilted forward, the horizontal component of which accelerates the aircraft as forward flight thrust, and the vertical component of which decreases accordingly; Step 3, when the airspeed of the aircraft reaches a value that the aerodynamic lift generated by the blended wing body structure is sufficient to support its weight, control the three ducted fan propulsion units to generate a resultant thrust that mainly contributes to the horizontal forward flight direction to provide the required forward flight thrust for horizontal cruising.

14. A control method for the cruising of an aircraft, for the flight control of an aircraft as claimed in claims 1 to 9, characterized in that The control method includes a step of cruising in level flight: Control the three ducted fan propulsion units to generate a resultant thrust approximately horizontally forward, and its magnitude is equal to the aerodynamic drag of the aircraft in cruising state; Control the thrust of the left and right ducted fan propulsion units to eliminate the unintended yaw and roll moments of the aircraft; The main ducted fan propulsion unit and the left and right ducted fan propulsion units achieve pitch moment balance, so that the aircraft maintains stable horizontal straight flight.

15. The control method according to claim 14, wherein The control method also includes a step of yaw control: When the heading needs to be changed, generate a yaw control moment around the vertical axis by differentially adjusting the thrust of the left and right ducted fan propulsion units; When left turn is needed, control the thrust of the right ducted fan propulsion unit to be greater than that of the left ducted fan propulsion unit to generate a left yaw moment; When right turn is needed, control the thrust of the left ducted fan propulsion unit to be greater than that of the right ducted fan propulsion unit to generate a right yaw moment.

16. The control method according to claim 14, wherein The control method also includes a step of pitch control: when the flight altitude needs to be changed, generate a pitch control moment around the horizontal axis by adjusting the thrust ratio of the main ducted fan propulsion unit and the left and right ducted fan propulsion units; when climbing is needed, coordinate to increase the thrust of the left and right ducted fan propulsion units and / or decrease the thrust of the main ducted fan propulsion unit to generate a pitch moment that tilts the nose upward; when descending is needed, coordinate to increase the thrust of the main ducted fan propulsion unit and / or decrease the thrust of the left and right ducted fan propulsion units to generate a pitch moment that tilts the nose downward.

17. A control method for vertical landing of an aircraft, for flight control of the aircraft according to claims 1-9, characterized by, The control method comprises a phase of transition from horizontal flight to vertical landing, which comprises: by coordinating the thrust of the three ducted fan propulsion devices and controlling the aircraft attitude to pitch up, the resultant thrust force changes its effect on the aircraft from mainly providing horizontal forward flight thrust to mainly providing vertical upward lift; in this phase, the main lift source supporting the weight of the aircraft is switched from relying on the aerodynamic lift generated by the wing-body structure at forward speed to relying on the propeller lift generated by the three ducted fan propulsion devices.

18. The control method according to claim 17, wherein The phase of transition from horizontal flight to vertical landing is achieved by the following steps: a first step, control the aircraft to enter a landing attitude from a level flight state, by coordinating to increase the thrust of the main ducted fan propulsion device and to decrease the thrust of the left and right ducted fan propulsion devices, the aircraft generates a positive pitch angle, the direction of the resultant thrust force tilts upward and backward, its vertical component starts to increase to partially support the weight of the aircraft, and its horizontal component starts to decrease backward to begin to decelerate; a second step, continue to increase the thrust of the main ducted fan propulsion device and to decrease the thrust of the left and right ducted fan propulsion devices, the pitch angle of the aircraft continues to increase to near vertical, the effect of the resultant thrust force tends to be vertical upward lift, and the forward flight speed continues to decrease to near zero; a third step, when the aircraft enters a vertical hovering or slow descending state, control the three ducted fan propulsion devices to generate a resultant thrust force vertically upward, and control the descent rate by adjusting the thrust size, to achieve a smooth landing.

19. The control method according to claim 17, wherein The control method further comprises a vertical landing phase, which comprises: controlling the three ducted fan propulsion devices to provide vertical lift smaller than the weight of the aircraft to achieve controllable descent of the aircraft; by independently regulating the thrust of the three ducted fan propulsion devices, maintaining the stability of the aircraft attitude during descent and landing.

20. The control method according to claim 19, wherein The maintaining the stability of the aircraft attitude during descent and landing comprises: controlling the pitch attitude of the aircraft by adjusting the thrust of the main ducted fan propulsion device; controlling the yaw attitude of the aircraft by differentially adjusting the thrust of the left and right ducted fan propulsion devices; controlling the roll attitude of the aircraft by cooperatively adjusting the thrust of the left and right ducted fan propulsion devices.

Images