A low-speed longitudinal stability augmentation control surface for an aircraft without a horizontal tail and an aircraft having the same

Abstract

This application belongs to the field of aircraft control surface design, and particularly relates to a low-speed longitudinal stability control surface for a tailless aircraft and an aircraft having the same. The control surface includes a main wing (7), the main wing (7) having upper and lower wing surfaces supported by a rear spar of the main wing (8), and an arc-shaped groove for connecting the upper and lower wing surfaces is provided at the rear end of the main wing (7) for installing a flaperon (12); an upper cover plate (9), the rear end of which is lapped on the upper side of the front arc surface of the flaperon (12), and the front end of which is hinged to the upper wing surface of the main wing (7); a lower cover plate, including a front lower cover plate (10) hinged to the lower wing surface of the main wing (7) and a rear lower cover plate (11) fixed to the lower side of the front arc surface of the flaperon (12), and the other ends of the front lower cover plate (10) and the rear lower cover plate (11) are lapped with each other. This application effectively reduces the complexity of the flight control system design and improves the reliability and safety of aircraft flight.

Description

Technical Field

[0001] This application belongs to the field of aircraft control surface design, and particularly relates to a low-speed longitudinal stability-increasing control surface for a tailless aircraft and an aircraft having the same. Background Art

[0002] Tailless aircraft, especially those with a flying wing layout, have relatively common low-speed longitudinal moment characteristics. That is, before the aircraft reaches the stall angle of attack corresponding to the maximum lift coefficient (i.e., the "inflection point" of the lift coefficient), the derivative of the longitudinal moment coefficient with respect to the angle of attack gradually increases, changing from a negative value to a positive value. That is, the longitudinal moment coefficient first shows an "inflection point", and then continues to increase until the lift coefficient shows an inflection point. During this period, the longitudinal stability of the aircraft gradually decreases, changing from static stability to neutral stability and static instability. If an active flight control system is not used, the aircraft cannot fly normally and safely after the "inflection point" of the longitudinal moment coefficient and before the "inflection point" of the lift coefficient. Moreover, a considerable part of the lift coefficient and angle of attack of the aircraft cannot be used, and the flight performance of the aircraft is difficult to meet the expectations.

[0003] At present, the low-speed longitudinal stability increase of tailless aircraft mainly adopts the "soft" stability increase of the active flight control system. The "soft" stability increase of the active control system uses closed-loop state feedback to change the dynamic characteristics of the aircraft body and achieve the adjustment of the aircraft modal characteristics. The "soft" stability increase design of the active control system has improved the stability characteristics of tailless aircraft to a certain extent, making the relatively safe and reliable flight of tailless aircraft possible. However, the active control stability increase design often relies on subsystems such as sensors, flight control software, actuation systems, and control surfaces, which generally increases the complexity of the system and reduces the reliability. At the same time, the active control stability increase design is often restricted by conditions such as the deflection rate of the control surface, the control effect, and the deflection authority. Generally speaking, it is only a "repair" of the overall aerodynamic characteristics of the aircraft and does not allow a large range of changes in the stability characteristics of the aircraft to prevent the over-reduction of the control characteristics.

[0004] Compared with the "soft" stability increase using the active flight control system, the "hard" stability increase relying only on the aircraft body control surface has higher reliability and safety. When the "hard" stability increase cannot achieve the required stability, it is necessary to adopt a method combining "hard" and "soft" stability increases or a completely "soft" stability increase method. Since the emergence of tailless aircraft, people have been studying how to solve their stability problems. The related exploration and research on the "hard" stability increase of tailless aircraft have been carried out, but no implementation methods and approaches for the "hard" stability increase have been found. The main reason is that there are many constraints and great difficulties in the "hard" stability increase.

[0005] Since tailless aircraft do not have a horizontal tail, longitudinal trim mainly relies on simple flaps, ailerons, simple flaperons and other control surfaces at the trailing edge of the wing. Compared with conventional layout aircraft, these control surfaces are very close to the center of gravity of the aircraft, resulting in smaller longitudinal trim capability and larger lift loss caused by trimming. In order to achieve the comprehensive performance of tailless aircraft such as stealth, weight control, and simple structure, the "hard" stabilization measures required to be taken need to have small increment of nose-down moment, appropriate increment of longitudinal static stability, small lift loss, minimum or minimal increase in the number of mechanisms, simple mechanism control, small stealth impact, small weight increment, etc. Summary of the invention

[0006] In order to solve at least one of the above technical problems, the present application designs a low-speed longitudinal stabilization control surface for a tailless aircraft, which improves the low-speed longitudinal static stability of the aircraft through "hard" stabilization measures.

[0007] In a first aspect, the present application provides a low-speed longitudinal stabilization control surface for a tailless aircraft, mainly comprising:

[0008] A main wing, wherein the main wing has upper and lower wing surfaces supported by a rear wing spar of the main wing, and an arc-shaped groove connecting the upper and lower wing surfaces is provided at the rear end of the main wing;

[0009] A flaperon, the front end of which is arranged as a curved surface, and when the flaperon is controlled to deflect relative to the main wing, the curved surface rotates in the curved groove;

[0010] An upper cover plate, the rear end of which overlaps the upper side of the front end curved surface of the flaperon, and the front end of which is hinged to the upper wing surface of the main wing;

[0011] A lower cover plate, comprising a front lower cover plate hinged to the lower wing surface of the main wing, and a rear lower cover plate fixed to the lower side of the front end curved surface of the flaperon, the other ends of the front lower cover plate and the rear lower cover plate overlapping each other;

[0012] The actuating device is used to drive the upper cover plate to rotate upward around the hinge point between the upper cover plate and the main wing so as to form a first channel between the upper cover plate and the flaperon, and is also used to drive the front lower cover plate to rotate upward around the hinge point between the upper cover plate and the main wing so as to form a second channel between the front lower cover plate and the flaperon. The first channel and the second channel form a channel to guide the airflow on the lower surface of the main wing to flow to the upper surface of the flaperon.

[0013] Preferably, the flaperon is capable of rotating around a flaperon hinge point, and the flaperon hinge point of the flaperon is located at a first set distance behind the rear spar of the main wing, and the first set distance is 9% to 11% of the local chord length of the wing.

[0014] Preferably, the first set distance is 10% of the local chord length of the wing.

[0015] Preferably, the upper cover plate is hinged at a second set distance behind the rear spar of the main wing through an upper cover plate hinge point, and the second set distance is 3.5% - 4.5% of the local chord length of the wing. The front lower cover plate is hinged at a position of the main wing close to the rear spar of the main wing through a front lower cover plate hinge point, and the length ratio of the front lower cover plate to the rear lower cover plate is 8:2.

[0016] Preferably, when the upper cover plate rotates upward to the maximum angle around its hinge point with the main wing, the distance between the rear end of the upper cover plate and the upper end face of the flap aileron is 0.5% - 1.5% of the local chord length of the wing. The front lower cover plate rotates upward around its hinge point with the main wing until the rear end of the front lower cover plate touches the upper cover plate.

[0017] In the second aspect of the present application, an aircraft with a low-speed longitudinal stability augmentation control surface for a tailless aircraft is provided. The aircraft includes a left wing body and a right wing body. A left outer flap aileron and a left inner flap aileron are arranged at the rear end of the left wing body, and a right outer flap aileron and a right inner flap aileron are arranged at the rear end of the right wing body. Among them, at least one of the left outer flap aileron, the left inner flap aileron, the right outer flap aileron, and the right inner flap aileron is equipped with the low-speed longitudinal stability augmentation control surface for a tailless aircraft as described above.

[0018] Preferably, when the aircraft is in the takeoff or landing state, the upper cover plate and the front lower cover plate are controlled to deflect upward to open the first channel and the second channel. When the aircraft is in the cruise state, the upper cover plate and the front lower cover plate do not deflect.

[0019] The present application can change the static stability of the aircraft, achieve the improvement of the longitudinal static stability characteristics, effectively reduce the complexity of the flight control system design, reduce the aircraft rudder effectiveness requirements, increase the ability of the tailless aircraft to recover after stalling, and overall improve the reliability and safety of the aircraft flight. Description of the Drawings

[0020] Figure 1 It is a schematic diagram of the retracted state of the upper and lower cover plates of a preferred embodiment of the low-speed longitudinal stability augmentation control surface for a tailless aircraft in the present application.

[0021] Figure 2 It is a schematic diagram of the opened state of the upper and lower cover plates of a preferred embodiment of the low-speed longitudinal stability augmentation control surface for a tailless aircraft in the present application.

[0022] Figure 3 It is a schematic diagram of the structure of a tailless aircraft of a preferred embodiment in the present application.

[0023] Among them, 1 - tailless aircraft, 2 - air intake, 3 - exhaust port, 41 - left drag rudder, 42 - right drag rudder, 51 - left outer flap aileron, 52 - right outer flap aileron, 61 - left inner flap aileron, 62 - right inner flap aileron;

[0024] 7 - Main wing, 8 - Rear spar of the main wing, 9 - Upper cover plate, 91 - Hinge point of the upper cover plate, 10 - Front lower cover plate, 101 - Hinge point of the front lower cover plate, 11 - Rear lower cover plate, 12 - Flap - aileron, 121 - Hinge point of the flap - aileron. Detailed implementation mode

[0025] To make the purpose, technical solution and advantages of the implementation of this application clearer, the technical solution in the implementation mode of this application will be described in more detail below in conjunction with the accompanying drawings in the implementation mode of this application. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The described implementation mode is part of the implementation modes of this application, not all of the implementation modes. The implementation mode described below by referring to the accompanying drawings is exemplary and is intended to explain this application, and should not be construed as a limitation of this application. Based on the implementation modes in this application, all other implementation modes obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application. The implementation mode of this application will be described in detail below in conjunction with the accompanying drawings.

[0026] The first aspect of this application provides a low - speed longitudinal stability - enhancing control surface for an aircraft without a horizontal stabilizer, as Figure 1 and Figure 2 shown, mainly including:

[0027] The main wing 7, the main wing 7 has upper and lower wing surfaces supported by the rear spar 8 of the main wing, and an arc - shaped groove for connecting the upper and lower wing surfaces is arranged at the rear end of the main wing 7;

[0028] The flap - aileron 12, the front end of which is set as an arc - shaped surface. When the flap - aileron 12 is controlled to deflect relative to the main wing 7, this arc - shaped surface rotates in the arc - shaped groove;

[0029] The upper cover plate 9, the rear end of which overlaps on the upper side of the arc - shaped surface at the front end of the flap - aileron 12, and the front end is hinged to the upper wing surface of the main wing 7;

[0030] The lower cover plate includes the front lower cover plate 10 hinged to the lower wing surface of the main wing 7 and the rear lower cover plate 11 fixed to the lower side of the arc - shaped surface at the front end of the flap - aileron 12. The other ends of the front lower cover plate 10 and the rear lower cover plate 11 overlap each other;

[0031] An actuating device for driving the upper cover plate 9 to rotate upward around its hinge point with the main wing 7 so as to form a first channel between the upper cover plate 9 and the flap - aileron 12, and at the same time for driving the front lower cover plate 10 to rotate upward around its hinge point with the main wing 7 so as to form a second channel between the front lower cover plate 10 and the flap - aileron 12. The first channel and the second channel are used to guide the airflow on the lower surface of the main wing 7 to the upper surface of the flap - aileron 12.

[0032] The technical solution of this application adopts a combined design of a simple flaperon and its upper and lower front covers on a tailless aircraft. The combined upper and lower covers deflect upward at different angles. When the simple flaperon does not deflect, an air flow channel is formed between the simple flaperon and the upper cover. As Figure 2 shown, it increases the flow energy on the upper surface of the trailing edge of the wing, eliminates or slows down the flow separation on the upper surface of the trailing edge of the wing before the stall angle of attack, and improves the low-speed longitudinal static stability of the aircraft.

[0033] In some alternative embodiments, the flaperon 12 can rotate around the flaperon hinge point 121, and the flaperon hinge point 121 of the flaperon 12 is located at a first set distance behind the rear spar 8 of the main wing, and the first set distance is 9% - 11% of the local chord length of the wing.

[0034] In some alternative embodiments, the first set distance is 10% of the local chord length of the wing.

[0035] In some alternative embodiments, the upper cover 9 is hinged at a second set distance behind the rear spar 8 of the main wing through the upper cover hinge point 91. The second set distance is 3.5% - 4.5% of the local chord length of the wing. The front lower cover 10 is hinged at a position of the main wing 7 close to the rear spar 8 of the main wing through the front lower cover hinge point 101, and the length ratio of the front lower cover 10 to the rear lower cover 11 is 8:2.

[0036] In this embodiment, it can be considered that the flaperon 12 is designed at about 10% of the chord length behind the rear spar 8 of the wing. Between the rear spar 8 of the wing and the flaperon 12, an upper cover with a length of about 6% of the chord length and a front lower cover with a length of about 8% of the chord length and a rear lower cover with a length of about 2% of the chord length are designed on the side close to the flaperon 12.

[0037] In some alternative embodiments, when the upper cover 9 rotates upward to the maximum angle around its hinge point with the main wing 7, the distance between the rear end of the upper cover 9 and the upper end face of the flaperon 12 is 0.5% - 1.5% of the local chord length of the wing, and the front lower cover 10 rotates upward around its hinge point with the main wing 7 until the rear end of the front lower cover 10 touches the upper cover 9.

[0038] This application uses an actuating device. The upper cover can deflect upward around its front hinge point, and the front lower cover can deflect upward around its front hinge point until it contacts the upper cover. After the front lower cover and the upper cover deflect, an air flow channel can be formed with the flaperon. The rear lower cover is fixed on the rear wing beam of the wing through a support structure. Generally, the flaperon does not deflect. If there is a need for control and trimming, the flaperon can deflect upward or downward as needed.

[0039] The combined design of the simple flap aileron provided by this application and its upper and lower front covers can make full use of the original simple flap aileron and its upper and lower front cover mechanisms of the aircraft to achieve the synchronization of the longitudinal moment "inflection point" and the lift coefficient "inflection point" and the improvement of longitudinal static stability. Moreover, the mechanism control is simple and convenient, without affecting the original functions of the simple flap aileron, having little impact on the lift coefficient, weight and stealth performance of the aircraft, with a small increment of nose-down moment and an appropriate increment of longitudinal static stability, making full use of the lift coefficient and angle of attack of the aircraft, and expanding or enhancing the low-speed flight performance of the aircraft.

[0040] Compared with the "soft" stability augmentation using an active flight control system, the present invention, through the design of the control surface, does not require the active control of the control surface occupied by specific authorities and control effectiveness. Only by pre-setting the deflection of the control surface can the static stability of the aircraft be changed, achieving the improvement of the longitudinal static stability characteristics, effectively reducing the complexity of the flight control system design, reducing the aircraft control effectiveness requirements, increasing the ability of the tailless aircraft to recover after stalling, and overall improving the reliability and safety of aircraft flight.

[0041] The second aspect of this application provides an aircraft with a low-speed longitudinal stability augmentation control surface for a tailless aircraft, such as Figure 3 shown. This aircraft is a tailless aircraft 1, which has an air intake 2 at the front and an exhaust port 3 at the rear. The aircraft also includes a left wing main body and a right wing main body. At the rear end of the left wing main body, there are a left drag rudder 41, a left outer flap aileron 51 and a left inner flap aileron 61. At the rear end of the right wing main body, there are a right drag rudder 42, a right outer flap aileron 52 and a right inner flap aileron 62. It is characterized in that at least one of the left outer flap aileron 51, the left inner flap aileron 61, the right outer flap aileron 52 and the right inner flap aileron 62 is equipped with the low-speed longitudinal stability augmentation control surface for a tailless aircraft as described above.

[0042] In some alternative embodiments, when the aircraft is in the takeoff or landing state, the upper cover 9 and the front lower cover 10 are controlled to deflect upward, opening the first channel and the second channel in accordance with Figure 2 the way. When the aircraft is in the cruise state, the upper cover 9 and the front lower cover 10 do not deflect and are retracted in accordance with Figure 1 the way.

[0043] As described above, the above are only the specific embodiments of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in this application should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claimed rights.

Claims

1. A low-speed longitudinal stability augmentation control surface for a tailless aircraft, characterized in that, it includes: A main wing (7), the main wing (7) having upper and lower wing surfaces supported by a rear spar of the main wing (8), and an arc-shaped groove connecting the upper and lower wing surfaces is provided at the rear end of the main wing (7); A flap aileron (12), the front end of which is provided as an arc-shaped surface, and when the flap aileron (12) is controlled to deflect relative to the main wing (7), this arc-shaped surface rotates within the arc-shaped groove; An upper cover plate (9), the rear end of which is lapped on the upper side of the front arc-shaped surface of the flap aileron (12), and the front end is hinged to the upper wing surface of the main wing (7); A lower cover plate, including a front lower cover plate (10) hinged to the lower wing surface of the main wing (7), and a rear lower cover plate (11) fixed to the lower side of the front arc-shaped surface of the flap aileron (12), and the other ends of the front lower cover plate (10) and the rear lower cover plate (11) lap each other; An actuating device for driving the upper cover plate (9) to rotate upward around its hinge point with the main wing (7) so as to form a first channel between the upper cover plate (9) and the flap aileron (12), and at the same time for driving the front lower cover plate (10) to rotate upward around its hinge point with the main wing (7) so as to form a second channel between the front lower cover plate (10) and the flap aileron (12), and the first channel and the second channel form a flow of air current on the lower surface of the main wing (7) to flow to the upper surface of the flap aileron (12); The flap aileron (12) can rotate around a flap aileron hinge point (121), and the flap aileron hinge point (121) of the flap aileron (12) is located at a first set distance behind the rear spar of the main wing (8), and the first set distance is 9% - 11% of the local chord length of the wing; The upper cover plate (9) is hinged at a second set distance behind the rear spar of the main wing (8) through an upper cover plate hinge point (91), and the second set distance is 3.5% - 4.5% of the local chord length of the wing, and the front lower cover plate (10) is hinged at a position of the main wing (7) close to the rear spar of the main wing (8) through a front lower cover plate hinge point (101), and the length ratio of the front lower cover plate (10) to the rear lower cover plate (11) is 8:2; When the upper cover plate (9) rotates upward around its hinge point with the main wing (7) to the maximum angle, the distance between the rear end of the upper cover plate (9) and the upper end surface of the flap aileron (12) is 0.5% - 1.5% of the local chord length of the wing, and the front lower cover plate (10) rotates upward around its hinge point with the main wing (7) until the rear end of the front lower cover plate (10) touches the upper cover plate (9).

2. The low-speed longitudinal stability augmentation control surface for a tailless aircraft according to claim 1, characterized in that, the first set distance is 10% of the local chord length of the wing.

3. An aircraft having a low-speed longitudinal stability augmentation control surface for a tailless aircraft, the aircraft including a left wing main body and a right wing main body, a left outer flap aileron (51) and a left inner flap aileron (61) are provided at the rear end of the left wing main body, and a right outer flap aileron (52) and a right inner flap aileron (62) are provided at the rear end of the right wing main body, characterized in that, At least one of the left outer flap aileron (51), the left inner flap aileron (61), the right outer flap aileron (52), and the right inner flap aileron (62) is equipped with a low-speed longitudinal stability-enhancing control rudder surface of an aircraft without a horizontal tail as described in any one of claims 1-2.

4. An aircraft having a low-speed longitudinal stability-enhancing control rudder surface of an aircraft without a horizontal tail as described in claim 3, wherein, when the aircraft is in a takeoff or landing state, the upper cover plate (9) and the front lower cover plate (10) are controlled to deflect upward to open the first channel and the second channel, and when the aircraft is in a cruise state, the upper cover plate (9) and the front lower cover plate (10) do not deflect.

Images