WO2021238637A1

WO2021238637A1 - Sickle-winged vertical take-off and landing aircraft

Info

Publication number: WO2021238637A1
Application number: PCT/CN2021/092771
Authority: WO
Inventors: 高文; 赵轶; 何杨; 聂俊; 沈政
Original assignee: 高文
Priority date: 2020-05-27
Filing date: 2021-05-10
Publication date: 2021-12-02
Also published as: CN111591440A

Abstract

The present invention provides a sickle-winged vertical take-off and landing aircraft, which is of a high wing structure. The wing comprises a wing root part and a wing tip part; a leading edge of the wing root part is integrally straight, a trailing edge of the wing root part is in a convex triangle shape, and the leading edge part is provided with a separated tiltable wing plane; a power system and a rotor wing are mounted on the wing plane; the leading edge and the trailing edge of the wing tip part are both inclined and swept forward integrally compared with the wing root part. The present invention has the advantages of being high in hovering efficiency, good in stability and high in level flight efficiency.

Description

Sickle-wing vertical take-off and landing aircraft

Technical field

The invention relates to the technical field of aircraft, in particular to a sickle-wing vertical take-off and landing aircraft.

Background technique

In recent years, the requirements for environmental protection, low-carbon and low-noise vehicles have become higher and higher, and urban electric vertical take-off and landing aircraft have become more and more popular. In order to abolish the traditional way of pilots flying airplanes and realize the purpose of unmanned flight, many companies and scientific research institutes have done a lot of research on its flight control. Mobile phone connection start, satellite navigation, route planning, fund payment, etc. must be developed. A set of software systems, but in the vertical takeoff and landing layout of the aircraft itself, some relatively traditional layouts are still used in terms of structural optimization design, which have not played a positive role in improving flight efficiency.

At present, the world’s mainstream civil vertical takeoff and landing aircraft layouts are mainly divided into 7 categories, including wingtip power tilt layout, entire wing tilt layout, rotor and fixed wing combined layout, tailstock layout, rear three-point rotor layout, Front and rear multi-point power layout, pure rotor layout.

Among them, the main feature of the wingtip power tilting layout is that the power system is installed on the wingtips on both sides for tilting and vertical take-off and landing. The disadvantage of this layout is that a large amount of downwash is blown to the top of the wing when hovering, causing internal friction. And turbulence; and the entire wing tilting layout means that the entire wing is tilted. This aircraft has high level flight efficiency and hovering efficiency, but the disadvantage is that the huge erected wing in the hovering state is like a door panel, slightly A little crosswind will affect the attitude of the entire aircraft, which is difficult to control, and the aircraft with this layout requires a large tilting force, which is not good for the weight of the aircraft; the combined layout of rotor and fixed wing has become more popular in recent years, but It has the defect of high waste quality in level flight; the tailstock layout means that the tail is used as the landing gear to support the aircraft, and the aircraft always stays upright in the stopped state, like a rocket. The defect of this layout is that it is difficult for the pilot to get off the plane. , And the shutdown state is easily affected by crosswinds; the defect of the rear three-point rotor layout is that the tilt axis is too far from the aerodynamic pressure (lift) force line. At this time, the center of gravity of the aircraft is close to its aerodynamic center, so another rotor must be installed behind the fuselage. Balance the center of gravity, otherwise the center of gravity is too far from the tilt axis in the hovering state, which is very dangerous, so a fan must be installed at the tail to balance the pitch, but the excess fan at the tail is waste mass during level flight; front and rear multi-point power layout airplanes fly level When part or all of the power must be tilted forward, if part of the power is tilted, then other motors will become flat wind resistance. If all motors are tilted, there will be too large forward wind propeller surface, difficult to increase speed, excessive power consumption, excessive power, and tilt. Problems such as too many rotating drive mechanisms will inevitably affect the efficiency of level flight; the disadvantage of the pure rotary wing layout is that the efficiency of level flight is low.

Summary of the invention

Aiming at the problems existing in various layouts in the prior art, the present invention proposes a sickle-wing vertical take-off and landing aircraft with high level flight efficiency and good hovering state.

The present invention adopts the following technical solutions:

A sickle-wing vertical take-off and landing aircraft, which is an upper single-wing structure. Its wing includes a wing root part and a wing tip part. It is provided with a separate tiltable airfoil; a power system and a rotor are installed on the airfoil; the leading edge and the trailing edge of the wing tip part are both inclined, compared with the wing root part which is swept forward as a whole.

With the forward sweep of the wingtip position, the lift line of the wing will move forward, approaching the axis of rotation of the wing, and the closer the line of lift to the axis of rotation is, it is good for the plane's level flight and hovering. Control the lift line at the root of the wing. Part of the average chord line should be 10%-30% of the front to back direction. The more forward the axis of rotation is on the wing, the more beneficial it is to flight in theory, but it will affect the strength of the wing if it is too far forward. Consider that the position of the axis of rotation is also at 5%-35%, but the lift line can only approach or coincide with the axis of rotation, and cannot exceed the axis of rotation. The forward sweep angle of the wing tip determines the position of the lift line, and it is more appropriate to control the forward sweep angle at 5°--45°. The front and back mentioned in the technical solution are both the direction of the nose of the aircraft as the front and the rear part of the aircraft.

Further, the wing has a double-beam structure, the front beam is an ordinary straight spar, and the rear beam is a centrally curved spar; the front beam is the tilt axis of the separate tiltable airfoil .

Further, the tilt angle of the separable tiltable airfoil is in the range of 0-105°.

Further, the front beam and the rear beam on the left and right sides of the vertical take-off and landing aircraft pass through the upper part of the fuselage to form an inter-plug connection.

Further, a main landing wheel is fixed on the separate tiltable airfoil; the main landing wheel and the power system are respectively installed on different ends of the airfoil.

Further, the tail of the vertical take-off and landing aircraft is a V-shaped tail.

Further, the wing is bent forward from the root portion to the wing tip portion.

The beneficial effects of the present invention are:

(1) The wing root part of the present invention is provided with a separated semicircular tiltable wing surface, which can achieve 0-105° tilting. Therefore, when the aircraft is hovering, it can ensure that the rotor is in an unobstructed air-through state, and the propeller produces Most of the downwash flow is effective, so there is no internal friction and turbulence, and the hovering efficiency is high and stable. At the same time, when the plane is flying in level, the separated semi-circular tiltable wing surface can be integrated with the entire wing to make the plane It has the high efficiency of normal wing level flight.

(2) The overall forward sweep of the wing tip of the present invention can make the aerodynamic pressure (lift) force line of the entire wing move forward, thus reducing the distance between the pressure (lift) force line and the center of gravity. The flat tail slightly generates a downward deflection moment to enable the aircraft to cruise efficiently and improve flight stability. Compared with the existing aircraft, the lift line is set at about 40% of the wing root from the front to the back. The lift line in the present invention is closer Front, flying and hovering are more stable. At the same time, the forward sweep of the wing tip helps to widen the wing at the root of the wing, which is beneficial to install large-diameter blades, and it is beneficial to hover and cyclical moment change control pitch, and the trailing edge of the wing can retain a wider wing. The width provides sufficient strength and rigidity guarantee; and the forward-swept design brings a high lift-to-drag ratio, which will produce large aerodynamic lift at low speeds, has good stall controllability, and can increase the range to a certain extent; the forward-swept design also It can delay the stall time and reduce the stall speed, which is conducive to the progress of the tilting action.

(3) In the present invention, the main landing wheel is also designed on the separated semicircular tiltable wing surface, no additional landing gear is required, which reduces the weight of the whole aircraft, and uses the wing surface tilting to achieve the automatic retractable landing wheel. The purpose is to reduce the flight resistance during level flight; at the same time, the main landing wheel and the power system are installed on different ends of the wing surface, which can neutralize the unilateral gravity torque of the power system, and make the tilting driving force linear and stable. Angle of influence.

Description of the drawings

Figure 1 is a schematic diagram of the structure of the sickle-wing vertical take-off and landing aircraft of the present invention;

Figure 2 is a schematic diagram of the hovering state of the sickle-wing vertical take-off and landing aircraft of the present invention;

Fig. 3 is a schematic diagram of the horizontal flight state of the sickle-wing vertical take-off and landing aircraft of the present invention;

Figure 4 is a comparison diagram of the structure of a straight wing and a sickle wing;

Figure 5 is a schematic diagram of the front and rear beams inside the sickle wing;

Figure 6 is a schematic diagram of the sickle wing moment.

Detailed ways

The present invention will be further described below in conjunction with the drawings and embodiments. In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", " The orientation or positional relationship indicated by “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, “axial”, “radial”, etc. are based on the orientation or position shown in the drawings The relationship is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the pointed device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

As shown in Figures 1-6, the present invention proposes a sickle-wing vertical take-off and landing aircraft, which is an upper single-wing structure. , The rear edge is in the shape of a convex triangle, the front edge is provided with a separate tiltable wing surface 3, and the power system 4 and the rotor are installed on the wing surface; the front and rear edges of the wing tip part 2 are inclined, Compared with the wing root part 1 as a whole forward sweep; therefore, in a top view state, one side of the wing of the present invention is similar to a sickle, and is called a sickle wing; As shown in the figure, the wing is a double-beam structure, the front beam 5 is an ordinary straight spar, the rear beam 6 is a central curved spar, and the front beam 5 is a separate tiltable wing surface Tilting axis C, equipped with a separate tiltable wing surface for tilting pulley; the tilt angle range of the separated tiltable wing surface 3 is at least 0～105°, which can facilitate the plane's level flight and hovering state As shown in Figure 3, when the aircraft is in level flight, the separate tiltable wing surface 3 is integrated with the entire wing, so that the wing is the same as a conventional aircraft in normal level flight, which can ensure High level flight efficiency; as shown in Figure 2, when the aircraft is hovering, the rotor is in a horizontal state, and the underside of the rotor is in an unobstructed air-through state. Most of the downwash generated by the propeller is effective, so there is no Internal friction and turbulence, hovering efficiency is high and stable.

As shown in Fig. 4, compared with a straight wing, the sickle wing proposed in the present invention sweeps forward as a whole, so that the aerodynamic pressure (lift) line B1 of the entire wing moves forward, maximizing close to but not exceeding the tilt axis A1; In order to maximize the diameter of the partially separated semicircular tiltable airfoil with the wing root and improve the hovering efficiency, it is necessary to maximize the forward movement of the tilt axis. However, for a straight wing, the tilt axis A2 is too forward. The distance from the aerodynamic pressure (lift) force line B2 will be enlarged, which will cause many factors that are not conducive to flight.

Specifically, when the center of gravity of the aircraft is close to the tilt axis, for a straight-wing aircraft, the distance between the aerodynamic pressure (lift) force line B2 and the center of gravity becomes longer, and the flat tail is required to produce a large downward deflection balance during level flight. Torque is good. This will consume too much energy and cannot achieve the purpose of efficient cruise. For the sickle-wing aircraft proposed in this application, the aerodynamic pressure (lift) line of force B1 of the entire wing moves forward, which reduces it. In order to reduce the distance between the aerodynamic pressure (lift) force line B1 and the center of gravity, as long as the tail slightly generates a downward deflection moment during level flight, the aircraft can cruise efficiently.

When the center of gravity of the aircraft is close to the aerodynamic pressure (lift) force line, for a straight-wing aircraft, the distance between the tilt axis and the center of gravity becomes longer, which can meet the high efficiency in level flight, but it is seriously detrimental to hovering. The center of gravity is far away from the tilt axis. When hovering, the hanging pull force of the two propellers and the center of gravity cannot be balanced, and the fuselage will roll back. If you want to neutralize this imbalance through periodic torque change, you need to generate a large force difference between the front and rear of the propeller. It is neither safe nor economical, so only a device capable of controlling pitch and stability can be installed behind the fuselage, but this device is deadweight during level flight, that is, excess mass, which will reduce the efficiency of level flight; and the present invention proposes For the sickle-wing aircraft, because the distance between the tilt axis A1 and the aerodynamic pressure (lift) force line B1 is very narrow or collinear, no matter which line the center of gravity is close to between the two, it is both for level flight and hovering. No significant adverse effects, it is a solution that not only satisfies high-efficiency level flight, but also cancels or reduces the control pitch device at the tail of the fuselage while hovering. It only needs the forward and backward slight pitch caused by the synchronous periodic torque change of the two main rotors. The moment can control the pitch stability.

Therefore, in summary, the forward sweep of the wing tip of the sickle wing proposed by the present invention helps widen the wing at the wing root, facilitates the installation of large-diameter blades, improves hovering efficiency, and is effective for hovering and periodic torque change. , It is advantageous to control the pitch of the fuselage; in addition, the rear edge of the wing can retain a wider wing width to provide sufficient strength and rigidity; the forward sweep of the wing also brings a high lift-to-drag ratio, which will produce large The aerodynamic lift has low wave resistance, which can increase the range to a certain extent and reduce the stall speed, which is conducive to the progress of the tilting action.

In addition, as shown in Figures 5 and 6, the main landing wheels are fixed on the separate tiltable wing surface of the present invention, so there is no need to install additional landing gear, which can achieve the purpose of reducing the weight of the whole aircraft and utilize the wing surface tilt control The automatic retracting and unfolding of the main landing wheel can reduce the flight resistance during level flight; the main landing wheel and the power system are installed on different ends of the wing surface, so that the unilateral gravity torque of the power system can be neutralized, that is, the moment T1 and the moment T2 are mutually By offsetting, the tilting driving force is linear and stable without being affected by the angle; in addition, when the fuselage supports water landing, the buoyancy of the left and right tires can prevent the aircraft from being blown over by the side wind when the aircraft is parked on the water.

Obviously, the foregoing examples are merely examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the implementation of the present invention. For those of ordinary skill in the art, other changes or modifications in different forms can be made on the basis of the above description. It is unnecessary and impossible to list all the implementation methods here. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

A sickle-wing vertical take-off and landing aircraft includes a wing, the wing includes a wing root part and a wing tip part, wherein the wing root part is provided with a separate tiltable wing surface; The wing surface is equipped with a power system and a rotor; the wing tip part is swept forward as a whole compared to the wing root part, and the forward sweep angle is 5°--45°; the lift line of the wing is controlled at the wing root part 10%-30% of the average chord.
The sickle-wing vertical take-off and landing aircraft according to claim 1, wherein the wing is a double beam structure, the front beam is a straight spar with a tilting device, and the rear beam is a central curved wing Beam; The front beam is the tilting axis of the separate tiltable airfoil.
The sickle-wing vertical take-off and landing aircraft according to claim 1, wherein the position of the lift line is controlled behind the tilt axis of the tiltable wing surface.
The sickle-wing vertical take-off and landing aircraft according to claim 1, wherein the tilt angle of the separate tiltable wing surface ranges from 0° to 105°.
The sickle-wing vertical take-off and landing aircraft according to claim 2, wherein the front and rear beams on the left and right sides of the vertical take-off and landing aircraft pass through the upper part of the fuselage to form an inter-plug connection.
The sickle-wing vertical take-off and landing aircraft according to claim 1, wherein a main landing wheel is fixed on the separate tiltable wing surface; the main landing wheel and the power system are respectively installed on different ends of the wing surface .
The sickle-wing vertical take-off and landing aircraft according to claim 1, wherein the tail of the vertical take-off and landing aircraft is a V-shaped tail.
The sickle-wing vertical take-off and landing aircraft according to claim 1, wherein the leading edge of the wing root portion is linear, and the trailing edge is convex triangle; the separated tiltable wing surface is arranged on the wing root Part of the leading edge.
The sickle wing vertical take-off and landing aircraft according to claim 1, wherein the wing is bent forward from the root portion to the wing tip portion.
The sickle-wing vertical take-off and landing aircraft according to claim 1, wherein the wing root area accounts for 35%-70% of the wing area.