CN109703743B - A jet rudder surface for an aircraft with a wing-body fusion layout - Google Patents

Abstract

A jet flow control surface of an airplane with a wing body fusion layout is located at the rear part of an airplane body and is folded and unfolded through a driving mechanism, so that jet flow of an engine in front of the control surface is coupled, and the head raising moment of the airplane during taking off and landing is obviously improved. Compared with the traditional wing body fusion layout tail control surface, the wing body fusion layout tail control surface has higher control surface efficiency, and can obviously increase the provided head raising moment. Meanwhile, the force arm is long, so that the required head raising moment can be achieved with small lift loss, and the adverse effect on the lifting performance is small on the whole. The design of the driving mechanism which can be taken in the machine body does not influence the cruising performance.

Description

A jet rudder surface of an aircraft with a wing-body fusion layout

technical field

The invention relates to the design of a longitudinal control rudder surface of an aircraft with a wing-body fusion layout, in particular to a jet rudder surface located at the rear of the body.

Background technique

Compared with the conventional layout, the aircraft with wing-body fusion layout cancels the control surfaces such as the flat tail. Due to the flat lift body design, the smooth transition between the fuselage and the wing greatly reduces the overall wetted area and reduces the drag. It is one of the research hotspots of the future aircraft layout form.

One of the main challenges in the design of aircraft with a blended wing-body layout is the lack of longitudinal control capability caused by the cancellation of the horizontal tail, especially when taking off and landing at low speed, the trim pressure of the bowing moment is large, and it is often accompanied by a large loss of lift. The control surfaces of this layout are usually arranged on the wing and the trailing edge of the body. The position of the control surface on the trailing edge of the wing is close to the center of gravity, the control arm is short, and the efficiency of the control surface is low. However, the total amount of torque that can be provided is relatively limited. In the low-speed take-off and landing state, in order to generate enough head-up torque, it is often accompanied by a large lift loss, resulting in a change in the flight trajectory, and even a "sudden sinking" phenomenon. Requirements, in turn, the high-lift lift device also makes the demand for the head-up torque greater. Looking for a longitudinal control method that can minimize the loss of trim lift and meet the torque demand can not only reduce the length of the take-off and landing field, enhance the safety of take-off and landing, but also reduce the design pressure of the lifting device, which is conducive to maximizing the exploitation of the BWB layout. Advantage.

Aiming at the problem of insufficient head-up torque and large lift loss when the aircraft with wing-body fusion layout takes off and landing at low speed, some new control methods have also been proposed at home and abroad, such as: abdominal spoiler (Staelens, Y.D., Blackwelder, R.F., Page, M.A. ,Novel pitch control effectors for a blended wing body airplanes intakeoff and landing configuration.45th AIAA Aerospace Sciences Meeting AndExhibit,2007,Reno,Nevada);Aircraft with vertical stabilizers arranged on a central fuselage body and method,as well as control unit, for compensating a negative pitching moment. Patent No.: US8496203B2); Canard (Nasir, R.M., Kuntjoro, W., Wisnoe, W., Longitudinal Static Stability of a Blended-Wing-Body Unmanned Aircraft with Canard as Longitudinal Control Surface, J. Journal of Mechanical Engineering. 2012, 9(1), pp.99–121.) et al. Although the above control methods are helpful to increase the head-up moment during take-off and landing, there are also many problems: the abdominal spoiler is a kind of rudder surface arranged on the lower surface of the body. The lift decreases, and the overall lift increases at the same time as the lifting torque of the whole machine is increased. Under its working state, the resistance of the whole machine will increase significantly, which puts forward extremely high requirements on the thrust of the engine. At the same time, the torque that can be provided is relatively limited. The vertical tail stabilizer surface is arranged on the upper part of the vertical tail at both ends, and provides the head-up moment without affecting the lift through its symmetrical deflection, and does not introduce additional yaw moment, but its The head-up moment that can be provided is positively related to the resistance increment, and a large head-up moment will also bring a large resistance cost; the canard is arranged in front of the wing, playing a similar role as a flat tail, which can provide head-up torque while increasing lift, But at the same time, it increases the cruising resistance of the whole aircraft and deteriorates the static stability of the whole aircraft, especially the static stability margin of the wing-body fusion layout itself is not high or even statically unstable. Therefore, it is of great significance to obtain a longitudinal control method that can meet the head-up torque demand during low-speed take-off and landing at a small cost.

SUMMARY OF THE INVENTION

In order to overcome the problem of insufficient head-up moment at low speed take-off and landing, often accompanied by large lift loss, in the wing-body fusion layout aircraft using the back-supported engine, the present invention proposes a jet rudder surface for the wing-body fusion layout aircraft.

The jet rudder surface is located on the upper surface of the rear part of the body in the fusion layout of the wing body, and is slid along the arc-shaped slide rail under the drive of the push rod to realize the retraction and retraction of the rudder surface. The horizontal projection of the jet rudder surface in the retracted state is symmetrical with respect to the symmetry plane of the body, and is surrounded by four edge lines. The edge line at the rear of the jet rudder surface is an arc line and coincides with the rear edge of the body. The length L1=0.1L of the straight sides on both sides of the jet rudder surface, the L is the horizontal projection length of the outermost end face of the body in the spanwise direction, and the spanwise length D1 of the jet flow rudder surface is the same as the spanwise length of the body same.

The shape of any chord section of the jet rudder surface within its spanwise range is a symmetrical airfoil, the leading edge of the section is a circular arc BAD, and the leading edge radius is 0.1 times the chord length of the section airfoil; The upper wing surface BC of the fuselage is coincident with the body profile, and the upper wing surface BC is an arc surface. The lower airfoil DC of this section is symmetrical to the upper airfoil BC. After determining the shape and size of the jet rudder, the jet rudder is obtained from the tail of the fuselage by cutting. Connect the obtained jet rudder surface with the drive mechanism.

The jet rudder surface is close to the front edge line of the engine and the two edge lines on both sides of the symmetrical plane of the body are straight sides, and the two edge lines on both sides are parallel to each other.

The arc length of the arc-shaped slide rail is 1.5 cylinder L1, and the radius is 1.8 cylinder L1. L1 is the length of the straight sides on both sides of the jet rudder.

The jet rudder surface is obtained from the tail of the fuselage by cutting. Grooves are respectively machined on both sides of the jet rudder surface near the trailing edge, and the grooves are located within the range of 45% to 85% of the chord length of the side surfaces; a pulley block is installed in the grooves.

When connecting the jet rudder surface with the driving mechanism, one end of the two push rods in the driving mechanism is hinged with the two ends of the front edge of the jet rudder respectively. The two arc-shaped slide rails in the driving mechanism are respectively embedded in the grooves and cooperate with the pulley group, and the hydraulic actuator drives the jet rudder surface to slide along the arc-shaped slide rails through the push rod. Realize the retraction and release of the rudder surface.

When the jet rudder surface is open, the maximum backward amount L2 is 0.8L1, the maximum upward movement H2 is 1/2 of the height of the engine bracket, and the maximum deflection angle A1 is upwardly 30 degrees.

In the present invention, the jet rudder surface is obtained by cutting the body. In the open state of the jet rudder, the maximum backward amount L2 is 0.75L1, the maximum upward movement H2 is half the height of the engine bracket, and the maximum deflection angle A1 is 30o upward.

The jet rudder surface is retracted and retracted by a drive mechanism, and the drive mechanism includes the following main parts: a push rod, a circular arc slide rail, a rotating shaft, a hydraulic actuator, and a slide rail drive mechanism. Except for the rotating shaft, each of the above components is arranged symmetrically on each side of the rudder surface. Among the components, the rotating shaft is fixed inside the body, and the hydraulic actuator is connected with it and can rotate around it. One end of the push rod is hinged with the jet rudder surface, and can drive the jet rudder surface to slide along the arc-shaped slide rail under the action of the hydraulic actuator. The retraction of the slide rail.

When the jet rudder surface is retracted, the drive mechanism is located inside the body. In the take-off and landing state, the slide rail drive mechanism first extends the arc-shaped slide rail out of the body, and the hydraulic actuator drives the push rod to move, and then pushes and pushes the push rod. The hinged jet rudder slides to the corresponding position along the arc-shaped slide rail to work. After entering the flying state, the jet rudder surface is retracted, and the slide rail drive mechanism then retracts the arc-shaped slide rail into the fuselage.

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

1. Improve the control efficiency of the rear rudder surface of the body. The tail of the aircraft body with the existing wing-body fusion layout often adopts a simple rudder surface 1 as shown in Fig. 1, which can perform up and down deflection motion. Due to its longer lever arm, it is the rudder surface with the highest longitudinal control efficiency. The present invention further exploits the advantage of the long arm of the rudder surface at the rear of the body, so that it has a form similar to the Fuller flap, and produces the jet rudder surface 2 as shown in Figure 2. The backward and upward deviation of the rudder surface increases the negative camber of the rear of the body and the length of the arm of the rudder surface, which enhances the head-up moment and improves the control efficiency of the rudder surface.

2. The available deflection angle of the rudder surface has been improved. When the simple rudder surface 1 shown in FIG. 1 has a large up-declination angle, the flow separation at the rear of the rudder surface is easy to occur, which limits the control ability of the rudder surface. The jet rudder surface 2 can increase the energy of the additional surface layer through the flow of the slot under the rudder surface, delay the flow separation, and increase the available deflection angle of the rudder surface. Fig. 3 shows the surface flow shape of the simple rudder surface 1 with a large up angle. It can be seen that under the rudder surface, the streamline is in a spiral shape, and there is obvious flow separation. Figure 4 shows the flow pattern of the jet rudder surface 2 with the same size and the same declination angle. On the airfoil under the jet rudder surface, the streamlines are straight and maintain a good adhesion flow. Therefore, the jet rudder surface has a larger available deflection angle.

3. The coupling between the engine jet and the rudder surface is realized, and the head-up torque is significantly increased. As shown in Figure 1, the rudder surface at the rear of the body is difficult to use effectively even in the case of a large up-angle due to a certain distance from the jet flow of the engine. The jet rudder surface of the present invention can be moved up and deflected upward, so that the jet flow of the engine can have a significant impact on it, forming a high pressure area on the upper airfoil surface, increasing the pressure difference between the upper and lower surfaces of the rudder surface, and effectively providing a head-up moment. Figure 5 compares the pitching moment curve 3 when the simple rudder is retracted, the pitching moment curve 4 when the simple rudder is open, and the pitching moment curve 5 when the jet rudder is open. When the jet rudder surface is open, it will bring a more significant head-up moment than the simple rudder surface, and the amount of the head-up moment provided by the jet rudder surface is about twice that of the simple rudder surface. Figure 6 compares the pressure distribution 6 in the open state of the simple rudder, the pressure distribution 7 of the body in the open state of the jet rudder, and the pressure distribution 8 of the rudder in the open state of the jet rudder. It is worth noting that the pressure distribution of the rudder surface when the jet rudder surface is open8, due to the huge pressure difference between the upper and lower surfaces brought about by the engine jet, the rudder surface produces a significant negative lift. Along with the longer lever arm of the rudder surface, this negative lift brings a large amount of head-up moment, which is the reason why the jet rudder surface can provide more head-up moment more efficiently than the simple rudder surface.

4. The jet rudder has little adverse effect on the take-off and landing performance, and will not affect the cruising performance. When the rudder surface provides the head-up moment, it is often accompanied by a decrease in lift and an increase in drag, especially for the rudder surface with inefficient wing-body fusion layout, this problem is more prominent. Figure 7 compares the lift curve 9 with the simple rudder stowed, the lift curve 10 with the simple rudder open, and the lift curve 11 with the jet rudder open. It can be seen that the open state of the jet rudder will bring a larger lift loss than the simple rudder, but the increased loss is small, about 20%. Figure 8 compares the resistance curve 12 in the state where the simple rudder is retracted, the resistance curve 13 in the open state of the simple rudder, and the resistance curve 14 in the open state of the jet rudder. When the jet rudder surface is open, it will bring more resistance than the simple rudder surface, which is good for landing, but not good for take-off. In the take-off and landing state, more attention is paid to the change of aerodynamic performance at high angle of attack. With the increase of the angle of attack, the increased resistance is decreasing, and the increased resistance in the take-off state with a high angle of attack is already in a small order of magnitude. On the whole, considering that the control ability of the jet rudder surface is much stronger than that of the simple rudder surface, it will inevitably reduce the trim pressure of the inefficient wing trailing edge rudder surface, and the lift-drag loss caused by the trim will be reduced in general. . At the same time, since the jet rudder surface can be obtained by cutting the body, the rudder surface can be retracted to the original position in the non-working state, and the driving mechanism is hidden inside the body, which will not bring about the loss of aerodynamic performance during cruising.

Description of drawings

Figure 1 is a simple rudder surface commonly used in existing aircraft with wing-body fusion layout;

Fig. 2 is the jet rudder surface of the wing-body fusion layout aircraft proposed by the present invention;

Figure 3 is the surface flow pattern of a simple rudder surface under the condition of large up-angle;

Fig. 4 is the surface flow pattern of the jet rudder surface under the condition of large up angle;

Figure 5 shows the comparison of pitching moment characteristics in the state where the simple rudder surface is retracted, the simple rudder surface is open, and the jet rudder surface is open.

Figure 6 is a comparison of the pressure distribution in the open state of the simple rudder surface and the open state of the jet rudder surface.

Figure 7 is a comparison of the lift characteristics of the simple rudder surface in the retracted state, the simple rudder surface open state, and the jet rudder surface open state;

Figure 8 is a comparison of the resistance characteristics of the simple rudder surface in the retracted state, the simple rudder surface open state, and the jet rudder surface open state;

Fig. 9 is the structural representation of jet rudder surface;

Fig. 10 is the top view of the whole machine when the jet rudder surface is retracted;

Figure 11 is a schematic diagram of the chordwise section shape of the jet rudder;

Figure 12 is a schematic diagram of a jet rudder surface driving mechanism;

Fig. 13 is a side view of the jet rudder surface and its drive mechanism.

In the picture:

1. Simple rudder; 2. Jet rudder; 3. Pitching moment curve when simple rudder is retracted; 4. Pitching moment curve when simple rudder is open; 5. Jet rudder when open Pitching moment curve; 6. Pressure distribution under the open state of the simple rudder; 7. Pressure distribution of the body under the open state of the jet rudder; 8. Pressure distribution of the rudder under the open state of the jet rudder; 9. Simple rudder Lift curve in retracted state; 10. Lift curve in open state of simple rudder; 11. Lift curve in open state of jet rudder; 12. Resistance curve in retracted state of simple rudder; 13. Simple rudder 14. Resistance curve under the open state of the jet rudder; 15. The symmetry plane of the body; 16. The body; 17. The outermost end face of the body; 18. The engine; 19. The engine bracket; 20 .Push rod; 21. Arc-shaped slide rail; 22. Support; 23. Shaft; 24. Hydraulic actuator; 25. Slide rail drive mechanism; 26. Pulley block;

L: the horizontal projection length of the outermost end face of the body in the spanwise direction;

L1: the length of the straight sides on both sides of the horizontal projection of the jet rudder surface;

L2: jet rudder retreat amount;

H2: The displacement of the jet rudder surface;

A1: The deflection angle of the jet rudder surface.

Detailed ways

As shown in Figure 9, the jet rudder surface 2 provided by the present invention is located on the upper surface of the rear part of the wing body fusion layout body, and under the drive of the push rod 20, slides along the arc-shaped slide rail 21 to realize the retraction of the rudder surface.

The horizontal projection of the jet rudder surface 2 in the retracted state is symmetrical with respect to the body symmetry plane 15, and is surrounded by four edges, as shown in the shaded area in Figure 10, wherein the front edge line close to the engine 17 and the body symmetry plane 15 The two edges on both sides of the symmetry are straight, and the two edges on both sides are parallel to each other. The rear edge of the jet rudder is an arc and coincides with the rear edge of the fuselage. The length L1=0.1L of the straight sides on both sides of the jet rudder surface, the L is the horizontal projection length of the outermost end surface 17 of the body in the spanwise direction, and the spanwise length D1 of the jet rudder surface 2 is the same as that of the body 16. The spanning length is the same.

The shape of any chord-wise section of the jet rudder surface 2 in its span-wise range is a symmetrical airfoil. The chord-wise section at the symmetry plane 15 of the body is taken to describe the relevant features, and other positions are the same, as shown in Figure 11 shown. The leading edge of this section is a circular arc BAD, and the leading edge radius is 0.1 times the airfoil chord length of this section; the upper airfoil surface BC of this section is all coincident with the airframe surface, and the upper airfoil surface BC is an arc surface. The lower airfoil DC of this section is symmetrical to the upper airfoil BC.

After determining the shape and size of the jet rudder, the jet rudder is obtained from the tail of the fuselage by cutting.

The two sides of the jet rudder surface near the trailing edge are respectively machined with grooves, and the grooves are located within the range of 45% to 85% of the chord length of the side surfaces; a pulley block 26 is installed in the grooves.

The obtained jet rudder surface 2 is connected to the drive mechanism. Specifically, one end of the two push rods 20 in the driving mechanism is hinged to the two ends of the front edge of the jet rudder surface 2 respectively. The two arc-shaped slide rails 21 in the driving mechanism are respectively embedded in the grooves and cooperate with the pulley group 26. The hydraulic actuator 24 drives the jet rudder surface 2 along the arc-shaped through the push rod 20. The slide rail 21 slides to realize the retraction of the rudder surface. When the jet rudder surface 2 is open, the backward amount L2 is at most 0.8L1, the upward movement amount H2 is at most 1/2 of the height of the engine mount 19, and the deflection angle A1 is at most 30 degrees upward.

As shown in FIGS. 12 and 13 , the drive mechanism includes two push rods 20 , two arc-shaped slide rails 21 , two hydraulic cylinders 24 , two slide rail drive mechanisms 25 , a support 22 and a rotating shaft 23 . The rotating shaft 23 is located in the body, and is installed on the support 22; the support is located in the body and fixed on the upper surface of the body. Hydraulic cylinders 24 are mounted on the ends of the two ends of the rotating shaft, respectively. One end of the two push rods 20 is respectively hinged with the piston rod in the hydraulic actuator, and the other end is hinged with the front edge of the jet rudder respectively, and under the action of the hydraulic actuator 24, the jet rudder surface 2 is driven along a circle. The arc-shaped slide rail 21 slides to realize the retraction and release of the rudder surface.

One end of the arc-shaped slide rail 21 is loaded into the slide rail drive mechanism 25 inside the body, the other end passes through the jet rudder surface 2, and an end plate 27 is installed at the end. When the jet rudder surface moves to the open state , the surface of the jet rudder surface forms a complete smooth curved surface through the end plate, as shown in Figure 13. The arc length of the arc-shaped slide rail 21 is 1.5 cylinders L1, and the radius is 1.8 cylinders L1. L1 is the length of the straight sides on both sides of the jet rudder.

In this embodiment, when the jet rudder surface 2 is in the retracted state, the driving mechanism is located inside the body, and the end plate 27 of the slide rail is flush with the upper surface of the jet rudder surface 2 to ensure that the surface of the rudder surface is completely formed Smooth curved surface; in the take-off and landing state, the slide rail drive mechanism 25 first extends the arc-shaped slide rail 21 out of the body under the action of the internal motor, and the hydraulic actuator 24 drives the push rod 20 to move, and then pushes the push rod. The hinged jet rudder surface 2 slides along the arc-shaped slide rail 21 to the corresponding position for work. After entering the flying state, the push rod 20 retracts the jet rudder surface 2 to the original position, and the slide rail drive mechanism 22 then moves the arc-shaped rudder surface 2 to the original position. The sliding rail 21 is retracted into the body until the end plate 27 of the sliding rail is flush with the surface of the jet rudder surface.

Claims (6)

1. A jet flow control surface of a wing body fusion layout airplane is characterized in that the jet flow control surface is positioned on the upper surface of the rear part of the wing body fusion layout airplane body and slides along an arc-shaped slide rail under the driving of a push rod to realize the retraction and release of the control surface; the horizontal projection of the jet flow control surface in a retraction state is symmetrical about a symmetry plane of the engine body and is enclosed by four side lines; the sideline at the rear part of the jet flow control surface is an arc line and is superposed with the rear edge of the engine body; the length L1 of straight edges on two sides of the jet flow control surface is 0.1L, the L is the horizontal projection length of the outermost end surface of the engine body in the spanwise direction, and the spanwise length D1 of the jet flow control surface is the same as the spanwise length of the engine body;

the wing body fusion layout airplane adopts a back-support type engine;

the jet control surface can move upwards and deflect upwards, so that the jet flow of an engine can cause remarkable influence on the jet control surface, a high-pressure area is formed on the upper airfoil surface of the jet control surface, and the pressure difference between the upper surface and the lower surface of the control surface is increased;

the jet flow control surface can increase the energy of the boundary layer through the flow of a slot below the control surface, delay the flow separation and improve the available deflection angle of the control surface;

the shape of any chord-direction section of the jet flow control surface in the spanwise range is a symmetrical airfoil shape, the front edge of the section is an arc BAD, and the radius of the front edge is 0.1 time of the chord length of the airfoil shape of the section; the upper wing surface BC of the section is superposed with the profile of the machine body, and the upper wing surface BC is a cambered surface; the lower airfoil surface DC of the profile is symmetrical to the upper airfoil surface BC; after the shape and the size of the jet flow control surface are determined, the jet flow control surface is obtained from the tail of the engine body through cutting; and connecting the obtained jet flow control surface with a driving mechanism.

2. The jet control surface of an airplane with the fused wing and body layout as claimed in claim 1, wherein the jet control surface is close to the front side line of the engine, and two side lines of two sides symmetrical to the symmetrical plane of the airplane body are straight edges, and the two side lines of the two sides are parallel to each other.

3. The jet flow control surface of an airplane with the fused wing body layout as claimed in claim 1, wherein the two side surfaces of the jet flow control surface near the trailing edge are respectively provided with a groove, and the grooves are positioned in the chord length range of 45% -85% of the side surfaces; a pulley block is arranged in the groove.

4. The jet flow control surface of an airplane with the wing body fusion layout according to claim 1, wherein when the jet flow control surface is connected with a driving mechanism, one ends of two push rods in the driving mechanism are respectively hinged with two ends of the front edge of the jet flow control surface; two arc-shaped sliding rails in the driving mechanism are respectively embedded into each groove and matched with the pulley block, and the hydraulic actuator cylinder drives the jet flow control surface to slide along the arc-shaped sliding rails through the push rod, so that the control surface is folded and unfolded.

5. The jet rudder surface of an airplane with a fused wing-body layout as claimed in claim 1, wherein the retreating amount L2 in the open state of the jet rudder surface is 0.8L1 at most, the upward moving amount H2 is 1/2 at the maximum of the height of an engine bracket, and the deflection angle A1 is 30 degrees at most.

6. The jet rudder surface of an airplane with the fused wing body layout as claimed in claim 1, wherein the arc length of the arc-shaped slide rail is 1.5L1, and the radius of the arc-shaped slide rail is 1.8L 1; l1 is the length of the straight edge on both sides of the jet flow control surface.

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