CN106927021A - Fan wing unmanned plane - Google Patents

Abstract

The invention relates to the field of unmanned aerial vehicles, and discloses a fan-wing unmanned aerial vehicle, which improves the flight efficiency and control performance of the fan-wing unmanned aerial vehicle. The invention comprises a wing, a cross-flow fan and a rectifying plate, the cross-flow fan is arranged at the rear of the wing and arranged along the span of the wing; the rectifying plate is arranged above the cross-flow fan, and the rectifying plate is controlled by a steering gear for adjusting the cross-flow fan The size of the airflow channel; the cross-flow fans on the left and right wings of the drone are controlled by different motors. The invention is applicable to fan-wing unmanned aerial vehicles.

Description

fan wing drone

technical field

The invention relates to the field of unmanned aerial vehicles, in particular to fan-wing unmanned aerial vehicles.

Background technique

Due to its unique flight principle and flight performance, fan-wing aircraft has attracted the attention of relevant research institutions in the United States, Britain, Iran, Israel and other countries. With the support of NASA in the United States and SMART in the United Kingdom, research institutions such as Imperial College, Kingston University, and FanWing Company in the United Kingdom, Syracuse University, NavalPostgraduate School, and Propulsive Wing Company in the United States, and Iran University of Science and Technology in Iran have developed fan-wing aircraft. The principle, configuration, aerodynamic characteristics, structural optimization and other aspects of theoretical and experimental research, and the principle prototype was manufactured.

my country's research on fan-wing aircraft is still in its infancy, mainly concentrated in universities and research institutes. Most of the research on fan-wing aircraft is in the stage of theoretical exploration. Niu Zhongguo and Jiang Jiali of the Chinese Academy of Aerodynamics studied the overall layout of the fan-wing aircraft, and the effects of rotor speed, blade deflection and flight speed on the aerodynamic characteristics of the fan-wing aircraft. influences. Di Nansi from East China University of Science and Technology studied the unsteady flow and static pressure distribution of the fan airfoil by using the CFD method, and proved that 80% of the lift of the fan blade comes from the eccentric vortex existing in the cross-flow fan. Nanjing University of Aeronautics and Astronautics, Air Force Engineering University, etc. have also done some exploratory work in the field of fan-wing aircraft, and have made a fan-wing UAV placed at the front end of the wing and successfully tested it, but it has not achieved differential speed control. , and there is still huge room for improvement in flight efficiency.

At present, the fan-wing aircraft mainly has the following problems:

1. The overall layout of the current fan-wing UAV is not perfect, and the pitch performance of the UAV is poor, and it is prone to stall at high angle of attack;

2. For the control of the fan blades, the differential motion cannot be realized, complex actions cannot be completed, and the operation efficiency is low;

3. The structure of the fuselage is complex, which increases the weight of the whole machine;

4. The flight efficiency is low, and the layout of various substructures is unreasonable.

Contents of the invention

The technical problem to be solved by the present invention is to provide a fan-wing UAV to improve the flight efficiency and control performance of the fan-wing UAV.

In order to solve the above problems, the technical solution adopted in the present invention is: fan-wing unmanned aerial vehicle, comprising wing, cross-flow fan and rectifying plate; The cross-flow fans on the wings are controlled by different motors; the rectification plate is set above the cross-flow fan and controlled by the steering gear, and the rectification plate is used to adjust the size of the airflow channel of the cross-flow fan.

Further, a wingtip end plate is provided at the end of the wingtip of the wing.

Further, the aileron is also included, and the aileron is located at the tail end of the wing; the aileron is controlled by the servo to provide pitch and roll moments.

Further, the fan-wing UAV can be divided into five parts as a whole: the left wing tip end plate, the left wing part, the middle fuselage part, the right wing part, and the right wing tip end plate; among them: the left wing part and the right wing Parts are distributed from front to back: front fairing, lithium battery, fan plus rectifier, aileron; the middle fuselage part is distributed from front to back are payload, communication device, flight control device, motor, rudder machine.

The present invention has the following beneficial effects:

1. Since the overall configuration of the present invention adopts the flying wing layout, the cross-flow fan is arranged at the rear of the wing, and the wingtip end plate is used to reduce the spanwise flow around the wing, which greatly improves the working efficiency of the cross-flow fan. Since the cross-flow fan is placed at the rear, the lift center of the aircraft is moved backward, which can greatly ensure the pitch stability of the fan-wing aircraft. Due to the short take-off and landing distance, the sliding take-off and landing is adopted, and the wing tip end plate is used as the supporting surface, which can save the extra weight and resistance caused by installing the landing gear. The rotation of the cross-flow fan can bring a large amount of airflow, and the boundary layer can be adjusted through the rectification plate, which can ensure that the aircraft can not stall at a high angle of attack.

2. Since the cross-flow fans on the left and right wings are controlled by different motors, the control channels are different, and the roll and yaw are controlled by adjusting the speed difference between the left and right fans to improve the control efficiency of the aircraft;

3. The fuselage mechanism is simple. The fan-wing aircraft can completely cancel the horizontal tail and vertical tail, but simply adjust the aileron linkage or differential to control the pitch and roll, reducing the weight and structural complexity of the aircraft.

4. High flight efficiency. With the movable rectifying plate above the cross-flow fan, the size of the flow channel can be adjusted. During take-off or low-speed level flight, increasing the flow path to inhale more air can obtain a larger lift increase. In the cruising stage, the flow path can be narrowed, the resistance can be reduced, the performance of both high and low speeds can be achieved, and the flight efficiency can be improved.

Description of drawings

Fig. 1 is the overall layout drawing of embodiment fan-wing aircraft;

Fig. 2 is a schematic diagram of traditional fan-wing aircraft flight;

Fig. 3 is the flight schematic diagram of the fan-wing aircraft of the embodiment;

Figure 4 is a GOE-383 airfoil diagram;

Figure 5 is a GOE-383 airfoil diagram with a cross-flow fan installed at the rear;

Figure 6 is a comparison diagram of the two-dimensional pressure distribution of the original airfoil and the airfoil with a cross-flow fan added.

Numbers in the picture: DB is the wing tip end plate, 1 is the front fairing, 2 is the lithium battery, 3 is the fan plus rectifier, 301 is the cross-flow fan, 302 is the rectifier, 4 is the aileron, 5 is the payload, 6 7 is the flight control device, 8 is the brushless motor, 9 is the steering gear, JL is the left wing part, JM is the middle fuselage part, and JR is the right wing part.

detailed description

The embodiment provides a fan-wing UAV, as shown in Figure 1, the fan-wing UAV can be divided into five parts as a whole, namely: the left wing tip end plate DB, the left wing part JL, and the middle fuselage part JM , the right wing part JR, the right wing tip end plate DB; wherein: the left wing part JL and the right wing part JB are distributed sequentially from front to back: front fairing 1, lithium battery 2, fan plus rectifying plate 3, Aileron 4; the middle fuselage part are distributed in sequence from front to back are payload 5, communication device 6, flight control device 7, brushless motor 8, steering gear 9.

Cross-flow fan 301: The cross-flow fan is set at the rear of the wing and arranged along the span of the wing. It is made of high-strength aluminum alloy and has a size of 30mm*290mm. A vortex low-pressure area is formed inside the fan 301, which causes a pressure difference between the upper and lower surfaces of the wing, so that the wing obtains lift. At the same time, the blades act on the air to push out the airflow backwards, forming a forward thrust. The intensity of the vortex low-pressure area can be controlled by controlling the speed of the cross-flow fan 301, the installation angle of the blades and other factors, so as to realize the control of the lift and thrust of the fan-wing aircraft. Moreover, the cross-flow fans on the left and right wings are controlled by different brushless motors with different control channels, and the roll and yaw can be controlled by adjusting the speed difference between the left and right cross-flow fans 301, thereby improving the control efficiency of the aircraft.

Wing tip end plate DB: set at the end of the wing tip of the wing, it is used to reduce the flow around the wing span and greatly improve the working efficiency of the cross-flow fan. Due to the short take-off and landing distance, the sliding take-off and landing is adopted, and the wing tip end plate DB is used as the supporting surface, which can save the extra weight and resistance caused by the installation of the landing gear.

Steering gear 9: controls the movement of rectifying plate 302 and aileron 4.

Aileron 4: The aileron is located at the tail end of the wing and is used to provide pitch and roll moments.

Rectification plate 302: the rectification plate is arranged above the cross-flow fan, and the size of the flow channel can be adjusted. During take-off or low-speed level flight, increasing the flow path to inhale more air can obtain a larger lift increase, and at this time the rectifying plate 302 is tilted backward. In the cruising stage, the rectifying plate 302 can be tilted forward to narrow the flow path, reduce resistance, and improve flight efficiency, thereby realizing the high and low speed functions of the aircraft.

Lithium battery 2: Provide the energy for the whole flight.

Payload 5: Increase the functions of the aircraft, such as photography, reconnaissance, and combat capabilities.

Leading edge fairing 1: Reduces air resistance.

Brushless motor 8: drives the cross-flow fan 301 to realize transmission.

Traditional fan-wing aircraft and embodiment fan-wing aircraft airfoil comparison As shown in Figure 2, 3, the cross-flow fan 301 of traditional fan-wing aircraft is installed on the leading edge of fixed-wing aircraft wing, and the wing rear of the fan-wing aircraft of embodiment The cross-flow fan 301 at the top of the fixed wing is made of a hollow structure, and the airfoil is slotted on the slope section to increase the flow capacity of the wing, thereby better guiding the airflow to flow close to the airfoil. The new fan-wing aircraft is also equipped with a movable rectifying plate 301 on the cross-flow fan, which absorbs and guides the airflow into the cross-flow fan, and can adjust the size of the airflow inlet and outlet through the steering gear to control the aerodynamic characteristics of the aircraft, so that it can Get more lift and less drag during cruise. It can be seen from the comparison that the new fan-wing aircraft has two main advantages compared with the traditional fan-wing aircraft airfoil: (1) By embedding the cross-flow fan in the trailing edge of the wing, it can better guide the airflow attachment and improve the lift. Reduce drag; (2) Increase the movable rectifying plate to improve the take-off and cruise characteristics.

As shown in Figure 3, the flight principle of the embodiment is: utilize the cross-flow fan 301 that is placed on the rear upper surface of the wing to accelerate the air and provide lift and thrust at the same time. A large payload aircraft. When the airflow flows through the cross-flow fan, it is divided into two parts. One part of the airflow flows through the upper edge of the rectifying plate 302 and flows out along the inclined surface of the rear edge of the wing. The suction of the fan 301 is divided into two parts: ① After being accelerated by the rotating blade, it flows out along the slope of the trailing edge, merges with the previous part of the airflow, and accelerates the air flow on the surface of the slope; ② flows in the opposite direction along the arc-shaped upper surface of the wing. A prominent low-pressure eccentric vortex forms to the right of the center of the blade. The eccentric vortex forms a low-pressure area inside, which causes a large pressure difference between the upper and lower surfaces of the wing, thereby generating a larger part of the lift force, which is the main source of the lift force of the fan-wing aircraft.

The thrust obtained by the fan-wing UAV is composed of two parts: one part of the thrust is that when the blades rotate, the blades push the airflow backward to discharge, according to Newton's third law, the airflow provides the forward thrust for the blades, thus forming the thrust; the other part The thrust is provided by the eccentric vortex. Since the low-pressure eccentric vortex is mostly formed in the right position inside the blade, this affects the pressure distribution in the horizontal direction of the cross-flow fan, thereby generating a forward thrust.

Considering that the embodiment needs to install a cross-flow fan inside the wing, the airfoil with a large thickness ratio is selected as a benchmark, such as the GOE-383 airfoil shown in Figure 4. Since the wing is a trapezoidal wing with a swept angle, In order to ensure that the normal direction of the rotation axis of the cross-flow fan 301 is consistent with the flight direction, the cross-flow fan should be at the trailing edge of the chord at the root of the wing, and at the leading edge of the chord at the tip of the wing. In the embodiment, a GOE-383 airfoil is equipped with a cross-flow fan 301, and the maximum thickness of the airfoil is 20% of the chord length.

In order to obtain the aerodynamic parameters of the wing after the cross-flow fan is installed more specifically, the airfoil section in the middle section of the wing span is intercepted here, as shown in Figure 5, and the two-dimensional CFD simulation of the airfoil is carried out using Fluent software , the simulation results are shown in Figure 6. Fig. 6 has shown the comparison of the two-dimensional pressure distribution of the original airfoil and the airfoil with the cross-flow fan added. It can be seen that due to the acceleration of the airfoil upper surface by the cross-flow fan 301, the pressure on the upper surface of the leading edge is lower than that of the corresponding airfoil. The original airfoil; the low-pressure vortex generated by the rotation of the cross-flow fan 301 also makes the pressure of the cross-flow fan on the upper surface of the airfoil much smaller than that of the original airfoil, thereby greatly increasing the lift of the wing. It can be seen from Figure 6 that when the chord length of the wing is 0.5m, the airflow on the upper surface can be accelerated to about 12m/s at the airspeed of 5m/s and the speed of the cross-flow fan at 6000rpm, and the lift is about 45% higher than that of the original airfoil. %.

Example shows through testing:

1. The flying wing layout is adopted, and the cross-flow fan 301 is arranged at the rear of the wing along the span direction, and the wing tip end plate DB is used to reduce the cross-flow in the span direction of the wing, which greatly improves the working efficiency of the cross-flow fan. Since the cross-flow fan 301 is placed at the rear, the center of lift of the aircraft moves backward, which can greatly ensure the pitch stability of the fan-wing aircraft. Due to the short take-off and landing distance, the sliding take-off and landing is adopted, and the wing tip end plate DB is used as the supporting surface, which can save the extra weight and resistance caused by the installation of the landing gear. The rotation of the cross-flow fan 301 can bring a large amount of airflow, and can adjust the boundary layer, so as to ensure that the aircraft can not stall at a high angle of attack. The wind tunnel experimental data shows that the fan-wing aircraft still has the characteristics of no stall at high angles of attack, which is consistent with the simulation results.

2. The outer rotor brushless motor 7 is used as the power device to drive the cross-flow fan 301 to realize high-efficiency transmission. Due to the flying wing layout, the horizontal tail and vertical tail can be eliminated, and the lift and roll can be controlled only through aileron linkage or differential, which greatly reduces the weight and structural complexity of the aircraft.

3. The control system adopts a tailless design, and ailerons are installed on both sides of the trailing edge of the wing to provide pitch and roll moments at the same time. The spanwise cross-flow fan 301 is arranged at the rear of the wing, and the wingtip end plate DB is used to reduce the spanwise cross-flow 301 . The fan-wing aircraft can also control the lift and thrust by controlling the speed of the fan, and can also control the roll and yaw by adjusting the speed difference between the left and right cross-flow fans, so as to improve the control efficiency of the aircraft.

4. With the movable rectifying plate 302 above the cross-flow fan 301, the size of the flow channel can be adjusted. During take-off or low-speed level flight, increasing the flow path to inhale more air can obtain a larger lift increase. In the cruising stage, the flow path can be narrowed, the resistance can be reduced, and the flight efficiency can be improved.

It should be pointed out that the above descriptions only illustrate some principles of the present invention, since it is easy for those of ordinary skill in the same technical field to make some modifications and changes on this basis. Therefore, this description is not intended to limit the present invention to the specific structure and scope of application shown and described, so all corresponding modifications and equivalents that may be used belong to the patent scope of the present invention.

Claims (4)

1. Fan-wing unmanned aerial vehicle, comprising wing, cross-flow fan and rectifying plate, it is characterized in that, cross-flow fan is arranged on the rear portion of wing and is arranged along the span of wing, and the cross-flow fan on left and right wing uses Controlled by different motors; the rectifying plate is set above the cross-flow fan and controlled by the steering gear, and the rectifying plate is used to adjust the size of the airflow channel of the cross-flow fan. 2. The fan-wing UAV according to claim 1, wherein a wing tip end plate is provided at the end of the wing tip of the wing. 3. The fan-wing unmanned aerial vehicle as claimed in claim 2, is characterized in that, also comprises aileron, and aileron is positioned at the tail end of wing; Aileron is controlled by servo, is used for providing pitching and rolling moment. 4. The fan-wing drone according to claim 3, wherein the fan-wing drone is divided into five parts as a whole: left wing tip end plate, left wing part, middle fuselage part, right wing part, The right wing tip end plate; the left wing part and the right wing part are distributed in sequence from front to back: front fairing, lithium battery, fan plus rectifying plate, aileron; the middle fuselage part is distributed in sequence from front to back Payload, communication device, flight control device, motor, steering gear.