CN103057695A - Combined control surface of tailless airplane - Google Patents

Abstract

The utility model relates to a combined rudder surface of a tailless aircraft, which comprises a parallelogram-shaped embedded rudder surface and an elevon. The two straight sides of the parallelogram shape forming the embedded rudder surface and the elevons are all parallel to the central axis of the fuselage; the two hypotenuses of the parallelogram shape of the embedded rudder surface and the elevons are all parallel to the The trailing edge of the wing is parallel. The embedded rudder surface and the elevon in the combined rudder surface are at the same spanwise position of the wing, and the embedded rudder surface is located close to the leading edge of the wing. The trailing edge of the elevon coincides with the trailing edge of the wing. The deflection angle of the embedded rudder surface is up to 90°, and the deflection angle of the elevon is ±30°. The invention can increase the lift force and make up for the loss of lift force caused by the opening of the embedded rudder surface; increase the longitudinal static stability of the tailless layout, thereby reducing or eliminating the coupling rolling moment, can increase the separation flow area, and obtain a larger resistance increment , which effectively reduces the burden of longitudinal trimming and improves the efficiency of heading control.

Description

Combined rudder surface of a tailless aircraft

technical field

The invention relates to the design of a heading control rudder surface of a tailless wing-body fusion aircraft, in particular to a combined rudder surface of a tailless aircraft.

Background technique

Compared with conventional aircraft, the tailless wing-body fusion aircraft cancels the horizontal tail, elevator, vertical tail, rudder and other components, and adopts a flat lifting body fuselage design, and the wings and fuselage are smoothly integrated, thereby greatly reducing the wetness The area reduces the overall machine resistance and has high aerodynamic efficiency. The tailless fuselage aircraft will become the ideal aerodynamic layout form of the new generation of large passenger aircraft in the future with low fuel consumption, low emissions, and low noise as the main design goals.

The biggest challenge in the design of tailless body-integrated aircraft lies in the problems of heading stability and heading control caused by the cancellation of the traditional vertical tail design. In order to realize the heading control of the aircraft, coordinate roll maneuvers, resist landing sidewinds and alleviate asymmetric loads, realize full flight envelope flight controllability, and achieve satisfactory flight quality, the tailless layout requires a new type of heading control surface to replace the traditional The function of the vertical tail rudder must ensure sufficient yaw control moment.

At present, the main means to realize the directional control of tailless aircraft is to arrange resistance-type rudder surfaces on the wings, such as split rudders, embedded rudder surfaces, and full-motion wingtips. Among them, the embedded rudder surface has the advantages of simple structure, quick response, convenient maintenance, high heading control efficiency, and being arranged on the upper wing surface to facilitate stealth. It is an ideal heading control rudder surface. However, when the embedded rudder surface is used for heading control, the coupling rolling moment is often very large under the large deflection of the rudder surface, which is not conducive to completing the turning action, especially it cannot meet the requirements of horizontal turning and small slope turning; The pitching moment increment coupled with the rudder surface further reduces the longitudinal static stability of the tailless aircraft and increases the burden of longitudinal trimming. In order to reduce or eliminate the adverse effects of coupled rolling moments and coupled pitching moments, many rudder surfaces such as elevons, flaperons, and embedded rudder surfaces are often deflected at the same time to achieve the required maneuverability, resulting in the control law of rudder surfaces. Complexity, low safety factor and other issues. Therefore, how to obtain high directional control efficiency, low coupling rolling moment, and favorable pitching moment characteristics with as few rudder surface configurations as possible has become one of the key technologies in the design of tailless fuselage fusion aircraft.

Contents of the invention

In order to overcome the shortcomings of large coupled rolling moment and unfavorable pitching moment when the embedded rudder surface is deflected for heading control, the invention proposes a combined rudder surface for a tailless aircraft.

The invention includes embedded rudder surfaces and elevons. The external dimension of described embedded rudder surface and elevon 4 is identical, is parallelogram. The two straight sides of the parallelogram shape forming the embedded rudder surface and the elevons are all parallel to the central axis of the fuselage; the two hypotenuses of the parallelogram shape of the embedded rudder surface and the elevons are all parallel to the parallel to the trailing edge of the wing.

The embedded rudder surface and the elevon in the combined rudder surface are at the same spanwise position of the wing, and the position of the embedded rudder surface is close to the leading edge of the wing; the position of the elevon is close to the rear of the wing edge. The trailing edge of the elevon coincides with the trailing edge of the wing.

The spanwise distance D1=0.83L between the outer straight edge of the embedded rudder surface in the combined rudder surface and the central axis of the fuselage = 0.83L; The spanwise distance D2=0.63L. The chordwise length D3 of the embedded rudder surface and the chordwise length D4 of the elevon are respectively 0.3C, and the spanwise length is 0.2L respectively. The distance D5 between the embedded control surface and the adjacent surface of the elevon is 0.1C. Said L is the half-span length of the aircraft, and said C is the wing chord length at the position m at the outer leading edge of the combined rudder surface.

Both ends of the front edge of the embedded rudder are hinged to a hinge shaft fixed on the wing, and can deflect around the hinge shaft, with a maximum deflection angle of 90°.

The rotating shaft of described elevon is installed in the wing, and the leading edge of elevon is installed on this rotating shaft through bearing, and can do ± 30 ° deflection around this rotating shaft. When the deflection angle of the elevon is 0°, there is a smooth transition between the elevon and the embedded control surface.

In the present invention, a group of combined rudder surfaces are respectively arranged on the wings on both sides of the fuselage, and the combined rudder surfaces on the wings on both sides are symmetrical to each other.

The two straight sides of the embedded rudder surface and the elevon are parallel to the central axis of the fuselage, and the two hypotenuses are parallel to the trailing edge of the wing where they are located. The leading edge of the elevon is rounded so that it can deflect up and down about its axis of rotation. The embedded rudder surface and the elevons in the combined rudder surface are at the same spanwise position of the wing. The embedded rudder surface is installed near the leading edge of the wing; the elevon is installed near the trailing edge of the wing, and the trailing edge of the elevon coincides with the trailing edge of the wing.

When performing heading control, yaw to the left to open the left combined rudder surface, and yaw to the right to open the right combined rudder surface. Among them, the embedded rudder in the combined rudder surface is deflected upward, and the elevon is deflected downward. The combined rudder surface scheme is used for heading control. On the one hand, the elevons in the combined rudder surface can be used to change the camber of the wing, increase the lift, and compensate for the lift loss caused by the opening of the embedded rudder surface, thereby reducing or eliminating the coupling rolling moment. . On the other hand, the deflection of the combined rudder surface causes the distribution of the aerodynamic load of the whole machine to change. The downward deflection of the elevon in the combined rudder surface increases the aerodynamic load on the rear of the wing, which will bring about an increase in the pitching moment of the nose down, thereby increasing the tailless layout. Longitudinal static stability, and greatly reduce the longitudinal trim burden. More importantly, the combined rudder surface scheme can effectively use the interference between its embedded rudder surface and the elevon to increase the separation flow area and obtain a larger resistance increment, thereby greatly improving the heading control efficiency.

Compared with the prior art, the present invention has the following outstanding effects:

1. By combining the embedded rudder surface and the elevon to form a combined rudder surface, the efficiency of heading control is obviously improved. Tests have proved that when the embedded rudder surface of the combined rudder surface is deflected by 30° and the elevon is deflected by 30°, the yaw moment generated by it is increased by 30% to 70% compared with that of the embedded rudder surface alone.

2. Effectively reduces the coupling rolling moment brought about by directional control, and reduces the difficulty of lateral decoupling. When the embedded rudder surface in the combined rudder surface is deflected by 30° and the elevon is deflected by 30°, the coupling rolling moment can be basically eliminated, and the pure directional control moment can be obtained, which has the ability of self-decoupling, that is, no other rudder is needed Lateral decoupling is performed by using surface deflection, which reduces the need for rudder surface configuration and simplifies the rudder surface control law.

3. Increased the longitudinal static stability of the tailless aircraft. Since the tailless layout aircraft usually adopts a statically unstable design, its nose-up moment needs to be trimmed during flight. The deflection of the elevons in the combined rudder surface will change the wing camber, increase the aerodynamic load on the rear of the wing, and generate an incremental pitching moment, which increases the longitudinal static stability and reduces the burden of longitudinal trimming. When the embedded rudder surface in the combined rudder surface is deflected by 30° and the elevon is deflected by 30°, the longitudinal moment trim of the main flight state can be realized, and no other rudder surface deflection is needed to participate in the longitudinal trim, thus reducing the rudder surface Configuration needs, simplifies the control law of the rudder surface.

4. The deflection angle of the embedded rudder surface and elevon in the combined rudder surface can be reasonably adjusted according to the different requirements of different flight stages for yaw moment and roll moment. If a large yaw moment and a small coupled rolling moment are required to complete the lateral heading maneuver, the deflection of the embedded rudder surface can be increased, and the deflection of the elevon can be appropriately reduced; if a horizontal turning maneuver is required, the Appropriately increase the deflection of the elevon and reduce the deflection of the embedded rudder surface to eliminate the coupled rolling moment.

5. The combined rudder surface scheme increases the redundancy of heading control and improves flight safety. If the embedded rudder surface or elevon in the combined rudder surface fails and cannot be used, the remaining rudder surface can be recombined with other rudder surfaces such as flaperon to participate in the vertical and horizontal heading and attitude control of the tailless aircraft.

6. The combined rudder surface has good multifunctional properties. The combined rudder surface can be opened on one side or on both sides. When opened on one side, it can complete heading control and anti-crosswind flight; Stability; in the take-off and landing phase, it can be used to adjust the lift-drag characteristics of the whole machine and improve the take-off and landing performance.

Description of drawings

Accompanying drawing 1 is the top view of the whole aircraft of tailless wing-body fusion aircraft;

Accompanying drawing 2 is the top view of one side of the tailless fuselage fusion aircraft;

Attached drawing 3 is a partial schematic diagram of the combined rudder surface;

Accompanying drawing 4 has the schematic diagram of the airfoil profile of combined rudder surface;

Attached drawing 5 is a schematic diagram of deflection of combined rudder surface;

Attached drawing 6 is a partial enlarged view of the deflection of the embedded rudder surface;

Figure 7 shows the comparison of the yaw moment between the combined rudder surface and the single embedded rudder surface;

Accompanying drawing 8 is the comparison of the rolling moment between the combined rudder surface and the single embedded rudder surface;

Attached drawing 9 is the comparison of the pitching moment between the combined rudder surface, the single embedded rudder surface and the common rudder surface without opening;

Accompanying drawing 10 is the flow form of the state that the common rudder surface is not opened;

Accompanying drawing 11 shows the flow form of a single embedded rudder surface;

Accompanying drawing 12 flow form of combined rudder surface;

Accompanying drawing 13 compares the pressure distribution of the combined rudder surface, the single embedded rudder surface and the non-open state of the common rudder surface. in:

1. Central axis of fuselage; 2. Combined rudder surface; 3. Embedded rudder surface; 4. Elevon; 5. Wing trailing edge; 6. Wing leading edge; 7. Outer straight edge of embedded rudder surface; 8. Inner straight edge of embedded rudder surface; 9. Elevon shaft; 10. Wing profile; 11. Wing skin; 12. Hinge shaft of embedded rudder surface; 13. Yaw of single embedded rudder surface Moment; 14. The yaw moment of the combined rudder surface; 15. The rolling moment of the single embedded rudder surface; 16. The rolling moment of the combined rudder surface; 17. The pitching moment when the ordinary rudder surface is not opened; 18. The single embedded rudder surface 19. The pitching moment of the combined rudder surface; 20. The pressure distribution when the ordinary rudder surface is not opened; 21. The pressure distribution of the single embedded rudder surface; 22. The pressure distribution of the combined rudder surface.

L: the half-span length of the tailless-body fusion aircraft;

m: Outer leading edge of combined rudder surface;

C: Wing chord length where the outer leading edge m of the combined rudder surface is located;

D1: the spanwise distance from the outer straight edge of the combined rudder surface to the central axis of the fuselage;

D2: the spanwise distance from the inner straight edge of the combined rudder surface to the central axis of the fuselage;

D3: chord length of embedded rudder surface;

D4: Elevon surface chord length;

D5: the distance between the embedded rudder surface and the adjacent surface of the elevon;

δ1: deflection angle of embedded rudder surface;

δ2: Elevon deflection angle;

t: Thickness of embedded rudder surface.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings.

Figure 1 shows the top view of the tailless body fusion aircraft. The wings on both sides of the fuselage are respectively arranged with a group of combined control surfaces 2, and the combined control surfaces 2 on both sides of the wings are symmetrical to each other. Since the whole machine is geometrically symmetrical and the rudder surfaces are arranged symmetrically, the present invention is only described on one side, as shown in Fig. 2 .

The combined rudder surface 2 includes an embedded rudder surface 3 and an elevon 4 . The external dimensions of the embedded rudder surface 3 and the elevon 4 are the same, and both are parallelograms. The two straight sides of the parallelogram profile that constitute the embedded control surface 3 and the elevon 4 are all parallel to the fuselage central axis 1; the two sides of the parallelogram profile of the embedded control surface 3 and the elevon 4 The hypotenuses are all parallel to the trailing edge 5 of the wing where they are located. The leading edge of elevon 4 is arc-shaped, and the wing place that cooperates with this elevon 4 leading edge is also arc-shaped, to facilitate the deflection of this elevon 4.

The embedded control surface 3 in the combined control surface 2 and the elevon 4 are in the same spanwise position of the wing, and the embedded control surface 3 is installed near the leading edge 6 of the wing; the elevon 4 is close to Wing trailing edge 5 is installed. The trailing edge of the elevon 4 coincides with the trailing edge of the wing.

The spanwise distance D1=0.83L between the outer straight side 7 of the embedded steering surface 3 in the combined steering surface 2 and the fuselage central axis 1 = 0.83L; the inner straight side of the embedded steering surface 3 in the combined steering surface 2 8 The spanwise distance D2 from the central axis 1 of the fuselage = 0.63L. The chordwise length D3 of the embedded control surface 3 and the chordwise length D4 of the elevon 4 are respectively 0.3C, and the spanwise lengths are 0.2L respectively. The distance D5 between the embedded control surface 3 and the adjacent surface of the elevon 4 is 0.1C. Said L is the half-span length of the aircraft, and said C is the wing chord length at the position m at the outer leading edge of the combined rudder surface 2 .

The profiles of the embedded rudder surface 3 and the elevon 4 are obtained by dividing the original airfoil profile 10 .

After the chordwise and spanwise positions of the embedded rudder surface 3 on the wing are determined, they are directly obtained by cutting the wing skin 11 . The thickness t of the embedded rudder surface is the thickness of the wing skin, so that the embedded rudder surface can be completely embedded in the wing without changing the shape of the original wing. The two ends of the leading edge of the embedded rudder surface 3 are hinged with the hinge shaft 12 fixed on the wing, and can deflect around the hinge shaft, and the deflection angle is at most 90°.

After the chordwise position and the spanwise position of the elevon 4 on the wing are determined, they are directly obtained by cutting the wing. The leading edge of the elevon 4 is arc-shaped.

The rotating shaft 9 of elevon 4 is installed in the wing, and the leading edge of elevon 4 is installed on this rotating shaft by bearing, and can do ± 30 ° deflection around this rotating shaft. When the deflection angle of the elevon 4 is 0°, there is a smooth transition between the elevon 4 and the embedded control surface 3 .

In this embodiment, during heading control, the embedded control surface 3 and the elevons 4 in the combined control surface 2 will deflect simultaneously. Among them, the embedded rudder surface 3 is tilted upward, and the elevon 4 is tilted downward, as shown in Fig. 5 . After the embedded rudder surface 3 and the elevon 4 form a combined rudder surface, due to the mutual interference between the two rudder surfaces, a favorable flow pattern change will be formed, the separated vortex area will be expanded, and the resistance will be increased, resulting in greater deflection. Navigating moment, improve the efficiency of directional control. The downward deflection of the elevon 4 in the combined rudder surface 2 will increase the camber of the wing to compensate for the lift loss of the wing caused by the opening of the embedded rudder 3 on this side, thereby fundamentally reducing or eliminating the coupling rolling moment. In addition, since the elevon 4 is located at the rear of the wing, the rear loading effect of the wing brought about by its downward deflection will generate an incremental pitching moment, thereby increasing the longitudinal static stability of the statically unstable tailless aircraft, and at the same time reducing the longitudinal Balance the burden. The deflection angle and opening method of the embedded rudder surface 3 and elevon 4 can be adjusted according to the specific requirements of parameters such as lift, drag, pitch moment, yaw moment, and roll moment according to different flight states, so as to complete horizontal turning, Various tasks such as small-slope turning, horizontal maneuvering, anti-crosswind flight, and improvement of take-off and landing performance.

Using computational fluid dynamics simulation software, it is verified that the combined rudder surface of the present invention has high directional control efficiency, low coupling rolling moment, good aerodynamic performance with increased longitudinal static stability, and the flight speed is Mach number 0.2.

From the comparison of yaw moment in Figure 7, it can be seen that when the deflection angle of the embedded rudder surface in the combined rudder surface is δ1=30°, and the deflection angle of the elevon is δ2=30°, the deflection angle of the combined rudder surface generated under each angle of attack is Compared with the yaw moment 13 using the embedded rudder surface alone, the yaw moment 14 is significantly improved, and the apparent angle of attack is respectively increased by 30% to 70%, thus significantly improving the efficiency of heading control. The comparison of rolling moments in Figure 8 shows that while the combined rudder surface improves the directional control efficiency, the rolling moment 16 of the coupled combined rudder surface is greatly reduced compared with the rolling moment 15 of the embedded rudder surface alone. When the embedded rudder surface deflection angle δ1=30° and the elevon deflection angle δ2=30°, the combined rudder surface deflection configuration already has the ability to completely eliminate the coupled rolling moment, and can obtain pure heading control moment, realizing Self-decoupling, which reduces the need for rudder configuration during yaw maneuvers, thus simplifying the rudder control law.

The comparison of pitching moments in Fig. 9 clearly shows that when the embedded rudder surface is used alone, the pitching moment 18 of the embedded rudder surface alone produces a pitching moment increment for raising the head compared to the pitching moment 17 when the common rudder surface is not opened, which will increase The longitudinal static instability of tailless aircraft also increases the burden of longitudinal trimming. When the combined rudder surface is used, the pitching moment 19 of the combined rudder surface is compared with the pitching moment 18 of the single embedded rudder surface, which brings an increase in the pitching moment of bowing, which is beneficial to increase the longitudinal static stability of the tailless aircraft, and at the same time reduce the Longitudinal trim burden. From the above analysis, it can be seen that the favorable changes in the three-axis moments in Figures 7 to 9 clearly show the outstanding advantages of the combined rudder surface: high directional control efficiency, low coupling rolling moment, and increased longitudinal static stability. Type rudder can not do.

Combining the comparison of the flow patterns in the three states of Fig. 10 with the common rudder surface not open, Fig. 11 with the single embedded rudder surface, and Fig. 12 with the combined rudder surface, and the comparison of the pressure distribution in Fig. 13, it is further revealed that the combined rudder surface produces high directional control efficiency , low coupling rolling moment, and the physical mechanism of increasing longitudinal static stability. It can be clearly seen from Figure 10 that when the ordinary rudder surface is not opened, the upper and lower surfaces of the wing are all attached flow without separation. After opening the embedded rudder surface, due to the change of wing geometry, there is an obvious separation flow at the rear of the embedded rudder surface, as shown in Figure 11.

In Fig. 13, the pressure distribution 20 of the common rudder surface when it is not opened, the pressure distribution 21 of the single embedded rudder surface and the pressure distribution of the combined rudder surface are shown respectively. Comparing the pressure distribution in Figure 13, it can also be found that because the airflow in front of the embedded rudder is suddenly compressed by the embedded rudder, the flow velocity decreases and the pressure rises rapidly, forming a strong reverse pressure gradient, resulting in the circulation in this area being higher than that of ordinary rudders. The face is not opened and the state is greatly reduced, resulting in a loss of lift.

It can also be seen from Figure 11 that after the embedded rudder surface is opened, the induction of the separated vortex will form an obvious upwash effect at the trailing edge of the wing, which further reduces the circulation and intensifies the loss of lift. It can be seen that the emergence of the strong coupling rolling moment is mainly caused by the large lift loss of the wing on this side after the embedded rudder surface is opened, and the strong coupling rolling moment is unfavorable or even dangerous to complete the turning action of the aircraft. After the elevon and the embedded rudder surface constitute the combined rudder surface, the pressure distribution in Figure 13 shows that under the combined rudder surface configuration, the strong reverse pressure gradient in front of the embedded rudder surface still exists, and the lift still loses. However, unlike using the embedded rudder surface alone, since the elevon changes the camber of the wing, when the airflow reaches the trailing edge of the wing, it produces a significant downwash effect, as shown in Figure 12, which makes the wing The air velocity on the upper surface increases, which is reflected in the pressure distribution in Figure 13. The circulation at the rear of the embedded rudder surface is significantly increased, which makes up for the lift loss caused by the embedded rudder surface, thus fundamentally preventing the generation of large coupling rolling moments . In addition, the pressure distribution in Figure 13 also shows that after the elevon is deflected downward, the aerodynamic load on the rear of the wing increases, forming a rear loading effect, which will bring about an increase in pitching moment when the nose is lowered, which is conducive to increasing the longitudinal static stability of the tailless aircraft . More importantly, Figure 12 reflects that the downwash effect brought by the elevons makes the separated stagnant vortex area at the rear of the embedded rudder surface larger than that of Figure 11 when the embedded rudder surface is used alone, thus significantly increasing the combined rudder The resistance on one side of the surface is also the source of the combined rudder surface of the present invention that can obtain greater yaw moment to improve the efficiency of heading control.

Claims (5)

1. a combined rudder surface of tailless aircraft, is characterized in that, comprises embedded rudder surface and elevon; The external dimension of described embedded rudder surface and elevon 4 is identical, is parallelogram; Described composition The two straight sides of the parallelogram shape of the embedded rudder surface and the elevons are all parallel to the central axis of the fuselage; The trailing edge is parallel; the embedded rudder surface and the elevon in the combined rudder surface are at the same spanwise position of the wing, and the position of the embedded rudder surface is close to the leading edge of the wing; the position of the elevon Close to the trailing edge of the wing; the trailing edge of the elevon coincides with the trailing edge of the wing; A group of combined rudder surfaces are respectively arranged on the wings on both sides of the fuselage, and the combined rudder surfaces on the wings on both sides are symmetrical to each other. 2. the combined rudder surface of tailless aircraft as claimed in claim 1, is characterized in that, the outside straight edge of the embedded rudder surface in the described combined rudder surface is apart from the spanwise distance D1=0.83L of fuselage central axis; The spanwise distance D2 between the inner straight edge of the embedded rudder surface and the central axis of the fuselage in the above combined rudder surface is D2 = 0.63L; the chord length D3 of the embedded rudder surface and the chord length D4 of the elevon are 0.3C respectively , the span length is 0.2L; the distance D5 between the embedded control surface and the adjacent surface of the elevon is 0.1C; the L is the half-span length of the aircraft, and the C is the outer side of the combined control surface The chord length of the wing at the position m at the leading edge. 3. the combined rudder surface of tailless aircraft as claimed in claim 1, is characterized in that, the two ends of described embedded rudder leading edge are hinged with the hinge shaft that is fixed on the wing, and can deflect around this hinge shaft, deflection The angle is up to 90°. 4. the combined rudder surface of tailless aircraft as claimed in claim 1, is characterized in that, the rotating shaft of described elevon is installed in the wing, and the leading edge of elevon is installed on this rotating shaft by bearing, and can rotate around The shaft makes a deflection of ±30°. 5. The combined rudder surface of a tailless aircraft as claimed in claim 4, wherein when the deflection angle of the elevon is 0°, the elevon and the embedded rudder surface are smoothly transitioned.

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