Design method and structure suitable for secondary folding rudder of high-speed aircraft

Abstract

The invention relates to a design method and structure suitable for a secondary folding rudder of a high-speed aircraft, and belongs to the technical field of high-speed aircraft design. Through secondary folding of the control surface, the outer diameter of the aircraft and the outer contour size of the folded control surface can be effectively reduced, so that the size of an aircraft storage box is reduced, and the filling density is improved; the spanwise gap between the first-stage movable control surface and the second-stage movable control surface effectively prevents the influence of high-temperature airflow at the front edge on the control surface framework, and meanwhile, the problem that the thermal stress at the front edge is too high due to mismatching of thermal deformation can be solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-speed aircraft design, and particularly relates to a design method and structure of a secondary folding rudder suitable for a high-speed aircraft. BACKGROUND

[0002] High-speed aircrafts can cross long distances in a very short time, perform global rapid deployment and other tasks, and can significantly improve the national defense capability and scientific and technological progress, and have become an important development direction of national defense of various countries. In order to improve the combat performance and loading density, the shape size of the aircraft is increasingly strict for various types of storage platforms, and more aircrafts need to be loaded in a limited space, so it is necessary to reduce the profile size of the aircraft as much as possible. The folding rudder technology has become a key technology for solving the contradiction between the loading space and the control performance of the high-speed aircraft.

[0003] At present, the folding rudder suitable for high-speed aircrafts mostly adopts a single folding scheme, as shown in FIG. 1, which is limited by the outer diameter of the aircraft and the wing span of the rudder, and the outer profile size of the aircraft can be reduced to a certain extent after folding, but there is still a large gap between the storage box. Therefore, it is necessary to design a folding rudder capable of secondary folding for the high-density loading requirement of high-speed aircrafts, to further reduce the outer profile size of the aircraft after folding of the rudder surface, reduce the size of the storage box, and improve the loading density. Figure 1 SUMMARY

[0004] (I) Technical problem to be solved

[0005] The technical problem to be solved by the application is to provide a design method and structure of a secondary folding rudder suitable for a high-speed aircraft, so as to further reduce the outer profile size of the aircraft after folding of the rudder surface and improve the loading density.

[0006] (II) Technical scheme

[0007] In order to solve the above technical problem, the application provides a design method of a secondary folding rudder suitable for a high-speed aircraft, comprising the following steps:

[0008] Step 1: According to the overall design requirement, the design input is determined

[0009] According to the flight mission profile of the high-speed aircraft, the flight speed range, the flight height range and the flight attitude are determined; according to the aerodynamic requirement of the high-speed aircraft, the size, mass and moment of inertia of the rudder surface are determined; according to the structural space design requirement, the tail cabin outer diameter and the storage box inner diameter and other structural dimensions are determined; according to the control requirement of the high-speed aircraft, the deployment time of the rudder surface is determined;

[0010] Step 2: Design the folding seam according to the aerodynamic heat requirement

[0011] ​The structure of the secondary folding rudder 3 is designed to include two sets of unfolding and locking mechanisms inside the fixed rudder surface 4, the first level movable rudder surface 5, the second level movable rudder surface 6, the first level movable rudder surface leading edge 7, the second level movable rudder surface leading edge 8 and the internal two sets of unfolding and locking mechanisms; the fixed rudder surface 4 is connected with the servo cabin body and the rudder machine of the aircraft, and drives the first level movable rudder surface 5 to move through the unfolding and locking mechanism, and the first level movable rudder surface 5 drives the second level movable rudder surface 6 to move through another unfolding and locking mechanism; there are two groups of rotating matching surfaces between the fixed rudder surface 4 and the first level movable rudder surface 5 and between the first level movable rudder surface 5 and the second level movable rudder surface 6, and the connection between the two is realized through the rotating shaft 9;

[0012] The folding gap between the first level movable rudder surface leading edge 7 and the second level movable rudder surface leading edge 8 is designed along the length direction of the rudder surface, and a t2 gap is reserved between the two leading edges;

[0013] Step 3: geometric design: according to the tail cabin outer diameter and the storage box inner diameter, the length and folding angle of the two-level folding rudder are determined;

[0014] According to the storage box inner diameter R1 and the aircraft tail cabin outer diameter R2, the total length of the rudder wing is L, h is the thickness of the folding rudder, and the secondary folding rudder satisfies the shrinkage in the envelope size in the folded state, therefore, the maximum design length of each level movable rudder surface satisfies For the first level folding rudder, the maximum design length is L 1max =L1+a3+c1-c2, that is, the distance L1 from the rotating shaft of the first level folding rudder to the rotating shaft of the second level folding rudder, the folding gap length a3 of the second level folding rudder, the distance c1 between the rotating shaft of the first level folding rudder and the missile body and the distance c2 between the rotating shaft of the second level folding rudder and the first level folding rudder; the length of the first level folding rudder should be greater than 1 / 2 of the total length of the rudder wing; the maximum design folding angle of the first level folding rudder satisfies:

[0015] According to the folding gap length designed in step two, the rotating shaft position of the second level folding rudder is determined; the maximum design length of the second level folding rudder is L 2max =L-L1-c1+c2; the maximum folding angle of the second level folding rudder satisfies the calculation:

[0016]

[0017] Step 4: statics design: according to the inner wall constraint, the matching relationship between the two level torsion rods is determined, the first level torsion rod is located between the fixed rudder surface 4 and the first level movable rudder surface 5, and the second level torsion rod is located between the first level movable rudder surface 5 and the second level movable rudder surface 6, and is respectively used to provide initial driving for the corresponding rudder surface, that is, the first level movable rudder surface 5 and the second level movable rudder surface 6;

[0018] When the secondary folding rudder is retracted in the storage box, the end of the secondary folding rudder is constrained by the storage box, and the two folding rudder wings remain in the retracted shape under the bending moment of the torsion bar; the torsional moments of the two torsion bars are M1 and M2 respectively, and the torsional coefficients are k1 and k2 respectively, according to the force analysis of the rudder wing, the torsional moments of the two torsion bars are consistent, that is, M1 = M2; the torsional coefficients of the two torsion bars satisfy

[0019] Step 5: Dynamic design: according to the deployment time requirement, the stiffness of the two-stage torsion bar is determined;

[0020] After the rudder surface constraint is released, the deployment process of the secondary folding rudder is divided into two stages: the first stage, the first and second folding rudders are deployed simultaneously, when the secondary folding rudder is deployed to be in a straight line with the primary folding rudder, the deployment between the primary movable rudder surface 5 and the secondary movable rudder surface 6 is locked by the locking mechanism, at this time, the second stage is entered, the secondary folding rudder and the primary folding rudder form an integral body and rotate to deploy around the primary folding rudder rotating shaft;

[0021] The dynamic equation of the first stage is:

[0022]

[0023] wherein J1 and J2 are the moments of inertia of the primary folding rudder and the secondary folding rudder respectively, are the folding angles of the primary folding rudder and the secondary folding rudder respectively, and the two points above represent the second derivative;

[0024] In the first stage, the dynamic equation of the secondary folding rudder is arranged as:

[0025]

[0026] wherein the second term on the right side is a constant;

[0027] The deployment time of the secondary folding rudder is approximately calculated by the following formula:

[0028]

[0029] The dynamic equation of the second stage is:

[0030]

[0031] wherein m2 is the mass of the secondary folding rudder;

[0032] Therefore, in the second stage, the deployment time of the folding rudder is calculated by the following formula:

[0033]

[0034] The total deployment time of the secondary folding rudder is t总 = t1 + t2;

[0035] Suppose the rudder surface unfolding time of the designed secondary folding rudder is t 设计 , if t 总 < t 设计 , the rigidity of the torsion bar is determined according to t 总 , so that the secondary folding rudder meeting the design requirements is obtained.

[0036] The application also provides a working method of the secondary folding rudder with the structure.

[0037] The application also provides a high-speed aircraft comprising the secondary folding rudder with the structure.

[0038] The application also provides a working method of the high-speed aircraft.

[0039] (Three) beneficial effects

[0040] Compared with the prior art, the application can achieve the following beneficial effects through the above technical solutions:

[0041] 1. Through the secondary folding of the rudder surface, the outer diameter and the span length of the aircraft can effectively reduce the outer contour size of the folded rudder surface, thereby reducing the size of the storage box of the aircraft and improving the packing density.

[0042] 2. The spanwise gap between the primary movable rudder surface and the secondary movable rudder surface effectively prevents the influence of the high-temperature airflow at the leading edge on the rudder surface framework, and also alleviates the problem of excessive thermal stress caused by the mismatch of thermal deformation at the leading edge.

[0043] 3. The unfolding locking mechanism adopted by the application provides driving force by a torsion spring or a torsion bar, and uses a locking pin and a locking compression spring as the locking device after unfolding, and the structure is relatively simple, stable and has strong carrying capacity. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 is a schematic diagram of the outer contour size of the single folding rudder after folding in the prior art solution;

[0045] Figure 2 is a schematic diagram of the outer contour size of the secondary folding rudder after folding suitable for a high-speed aircraft;

[0046] Figure 3 is a design flowchart of the design method suitable for the secondary folding rudder of a high-speed aircraft;

[0047] Figure 4 is a schematic diagram of the unfolding state of the secondary folding rudder proposed by the application;

[0048] Figure 5 is a schematic diagram of the folded state of the secondary folding rudder proposed by the application;

[0049] Figure 6 is a schematic diagram of the geometric relationship between the folding state of the secondary folding rudder and the two side profiles;

[0050] Figure 7 is a schematic diagram of the statics analysis of the folding state of the secondary folding rudder;

[0051] Figure 8 is a sectional view of the unfolding and locking mechanism of the primary rudder.

[0052] In the figure, 1 is a tail cabin of a high-speed aircraft; 2 is a single folding rudder; 3 is a secondary folding rudder; 4 is a fixed rudder surface; 5 is a primary movable rudder surface; 6 is a secondary movable rudder surface; 7 is the leading edge of the primary movable rudder surface; 8 is the leading edge of the secondary movable rudder surface; 9 is a rotating shaft; 10 is an unfolding driving device; 11 is a locking pin compression spring; 12 is a locking pin.

[0053] L1 is the distance between the rotating shaft of the primary movable rudder surface and the rotating shaft of the secondary movable rudder surface; L2 is the distance between the rotating shaft of the secondary movable rudder surface and the tip of the secondary movable rudder surface; c1 is the distance between the rotating shaft of the primary movable rudder surface and the tail cabin; c2 is the distance between the rotating shaft of the secondary movable rudder surface and the primary rudder; d1 is the distance between the rotating shaft of the primary rudder and the locking pin; d2 is the distance between the rotating shaft of the secondary rudder and the locking pin. is the folding angle of the primary rudder; is the folding angle of the secondary rudder; a1 and a2 are shape parameters of the folding joint between the fixed rudder surface and the primary rudder, respectively; t1 is the gap size of the primary folding joint; a3-a7 are shape parameters of the folding joint between the primary rudder and the secondary rudder, respectively; t2 is the gap size of the secondary folding joint. DETAILED DESCRIPTION

[0054] In order to make the purpose, content and advantages of the present application clearer, the specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings and examples.

[0055] Referring to Figure 1 As shown in the figure, the single folding rudder 2 currently used on high-speed aircrafts determines the maximum folding angle of the rudder surface when the rudder surface is in the folded state, and the outer diameter of the tail cabin 1 of the aircraft determines the maximum folding angle of the rudder surface. When the rudder surface is folded to the maximum angle, the outer profile of the aircraft is limited by the rudder surface length. For the rudder surface shown in the figure, due to the large rudder surface length, the cross-sectional envelope size of the aircraft is large. Figure 1 As shown in the figure, the single folding rudder 2 currently used on high-speed aircrafts determines the maximum folding angle of the rudder surface when the rudder surface is in the folded state, and the outer diameter of the tail cabin 1 of the aircraft determines the maximum folding angle of the rudder surface. When the rudder surface is folded to the maximum angle, the outer profile of the aircraft is limited by the rudder surface length. For the rudder surface shown in the figure, due to the large rudder surface length, the cross-sectional envelope size of the aircraft is large.

[0056] Referring to Figure 2As shown in the single folding rudder 2, the application proposes a secondary folding rudder 3, which divides the original moving rudder surface into a first moving rudder surface and a second moving rudder surface, and adds a set of unfolding and locking mechanisms. When the first fixed rudder surface is folded to the maximum angle, the second moving rudder surface can also be folded to a certain angle relative to the first moving rudder surface, thereby reducing the outer contour size of the aircraft after the rudder surface is folded.

[0057] Referring to Figure 3 As shown in the figure, the application provides a secondary folding rudder design method for high-speed aircraft. The method mainly includes the following steps:

[0058] Step 1: According to the overall design requirements, the design input is determined.

[0059] According to the flight mission profile of the high-speed aircraft, the flight speed range, flight altitude range and flight attitude are determined. According to the aerodynamic requirements of the high-speed aircraft, the size, mass and moment of inertia of the rudder surface are determined. According to the structural space design requirements, the tail cabin outer diameter and storage box inner diameter are determined. According to the control requirements of the high-speed aircraft, the unfolding time of the rudder surface is determined.

[0060] Step 2: Design the folding joint according to the aerodynamic heating requirement.

[0061] According to the flight speed and altitude of the aircraft, the aerodynamic heating environment is analyzed to determine the heat insulation requirement of the folding joint. Referring to Figure 4 As shown in the figure, the secondary folding rudder 3 designed by the application mainly consists of a fixed rudder surface 4, a first moving rudder surface 5, a second moving rudder surface 6, a first moving rudder surface leading edge 7, a second moving rudder surface leading edge 8 and two sets of internal unfolding and locking mechanisms. The fixed rudder surface 4 is connected with the servo cabin body and the rudder of the aircraft, and drives the first moving rudder surface 5 to move through the unfolding and locking mechanism, and further, the first moving rudder surface 5 drives the second moving rudder surface 6 to move through another unfolding and locking mechanism (which has the same structure as the aforementioned unfolding and locking mechanism), so as to realize the deflection of the entire rudder surface according to the control command. There are front and rear two sets of rotating matching surfaces between the fixed rudder surface 4 and the first moving rudder surface 5, and between the first moving rudder surface 5 and the second moving rudder surface 6, and the connection between them is realized through the rotating shaft 9.

[0062] The folding division surface forms between the fixed rudder surface 4 and the first moving rudder surface 5, and between the first moving rudder surface 5 and the second moving rudder surface 6 are basically similar, the main difference is that the folding gap between the first moving rudder surface leading edge 7 and the second moving rudder surface leading edge 8 is designed along the length direction of the rudder surface, and a t2 gap is reserved between the two leading edges, which can ensure that the first moving rudder surface leading edge 7 can shield the high-temperature airflow at the leading edge, prevent the high-temperature airflow from entering the folding gap of the first moving rudder surface 5 and the second moving rudder surface 6, and cause the local temperature of the rudder surface skeleton to be too high. In addition, the gap between the two leading edges can effectively alleviate the problem of excessive local thermal stress caused by thermal deformation mismatch.

[0063] Step 3: Geometric design: according to the tail cabin outer diameter, storage box inner diameter, etc. to determine the length and folding angle of the two-stage folding rudder.

[0064] Referring to Figure 6 According to the storage box inner diameter R1 and the aircraft tail cabin outer diameter R2, the total length of the rudder wing is L, h is the thickness of the folding rudder, and the secondary folding rudder needs to meet the shrinkage in the envelope size in the folded state, so the maximum design length of each stage of the movable rudder surface should meet For the first stage of the folding rudder, the maximum design length is L 1max L1+a3+c1-c2, that is, the distance L1 from the rotation shaft of the first stage of the folding rudder to the rotation shaft of the second stage of the folding rudder, the folding seam length a3 of the second stage of the folding rudder, the distance c1 between the rotation shaft of the first stage of the folding rudder and the missile body, and the distance c2 between the rotation shaft of the second stage of the folding rudder and the first stage of the folding rudder. In addition, in order to ensure the stability of the rudder wing structure, the length of the first stage of the folding rudder should be greater than 1 / 2 of the total length of the rudder wing. If the total length of the rudder wing exceeds The secondary folding rudder design will no longer be applicable. The maximum design folding angle of the first stage of the folding rudder should meet:

[0065] According to the folding seam length designed in step two, the rotation shaft position of the second stage of the folding rudder is determined. The maximum design length of the second stage of the folding rudder is L 2max L-L1-c1+c2. The maximum folding angle of the second stage of the folding rudder should meet the calculation:

[0066] Step 4: Statics design: according to the inner wall constraint, determine the coordination between the two stages of the torsion bar (i.e. the following deployment driving device), the first stage of the torsion bar is located between the fixed rudder surface 4 and the first stage of the movable rudder surface 5, and the second stage of the torsion bar is located between the first stage of the movable rudder surface 5 and the second stage of the movable rudder surface 6, which are used to provide initial driving for the corresponding rudder surface, i.e. the first stage of the movable rudder surface 5 and the second stage of the movable rudder surface 6.

[0067] Referring to Figure 7 When the secondary folding rudder is shrunk in the storage box, the end of the second stage of the folding rudder is constrained by the storage box, and the two stages of the folding rudder wing (the first stage of the folding rudder and the second stage of the folding rudder) maintain the shrunk shape under the bending moment of the torsion bar. Let the torsional moments of the two torsion bars be M1 and M2, and the torsion coefficients be k1 and k2, respectively. According to the force analysis of the rudder wing, the torsional moments of the two torsion bars are consistent, i.e. M1=M2. Due to the different folding angles, the torsion coefficients of the two torsion bars should meet

[0068] Step 5: Dynamics design: according to the deployment time requirement, determine the stiffness of the two stages of the torsion bar.

[0069] After the rudder surface constraint is removed, the deployment process of the secondary folding rudder can be divided into two stages: in the first stage, the first and second folding rudders are deployed simultaneously, and because the second rudder has a small moment of inertia, the deployment time is shorter. When the second folding rudder is deployed to be in a straight line with the first folding rudder, the corresponding deployment and locking mechanism (the deployment and locking mechanism between the first movable rudder surface 5 and the second movable rudder surface 6) is locked, at which time the second stage is entered, the second folding rudder and the first folding rudder form an integral whole and are rotated and deployed around the rotation shaft of the first folding rudder.

[0070] The dynamic equation of the first stage is:

[0071]

[0072] wherein J1 and J2 are the moments of inertia of the first and second folding rudders respectively, m2 is the mass of the second folding rudder, are the folding angles of the first and second folding rudders respectively, and the two points above indicate the second derivative.

[0073] In the first stage, the dynamic equation of the second folding rudder can be arranged as:

[0074]

[0075] wherein because the deployment time of the first folding rudder is small, the second term on the right side can be regarded as a constant. This is a nonlinear differential equation, which usually needs to be solved by numerical methods. Because the stiffness of the torsion bar of the second folding rudder is much greater than that of the first folding rudder, it can be approximately considered that the first folding rudder does not deploy in the deployment process of the second folding rudder. Thus, the time calculated by this simplification is larger than the actual time, and therefore the structure calculated according to this simplification is reliable. Assuming that the aerodynamic resistance during the deployment process is small, the deployment time of the second folding rudder can be approximately calculated by the following formula:

[0076]

[0077] The dynamic equation of the second stage is:

[0078]

[0079] wherein m2 is the mass of the second folding rudder (i.e., the second rudder wing).

[0080] Therefore, in the second stage, the deployment time of the folding rudder is approximately calculated by the following formula:

[0081]

[0082] The total deployment time of the secondary folding rudder is t 总 = t1 + t2.

[0083] Assume the deployment time of the rudder surface of the designed double-folding rudder is t. 设计 If t 总 <t 设计 Then according to t 总 Determine the stiffness of the torsion bar.

[0084] If the existing torsion bar can guarantee that the rudder surface deployment time meets the design requirements, then a secondary folding rudder that meets the design requirements is obtained. Otherwise, the lengths of the two-stage folding rudders will be adjusted, and then the process will jump to step 3 to recalculate the lengths and folding angles of the two-stage folding rudders until the rudder surface deployment time t is met. 总 <t 设计 .

[0085] The deployment and locking mechanisms between the fixed control surface 4 and the primary moving control surface 5, and between the primary moving control surface 5 and the secondary moving control surface 6, are similar in form. (Refer to...) Figure 5 As shown, taking the unfolding and locking mechanism between the fixed control surface 4 and the primary moving control surface 5 as an example, the composition of the unfolding and locking mechanism is briefly described. The unfolding and locking mechanism mainly consists of a rotating shaft 9, an unfolding drive device 10, a locking pin 12, and a locking pin compression spring 11. The rotating shaft 9 is the reference for rotation when the control surface is folded and unfolded; the rotating shaft 9 passes through the fixed control surface 4 and is fixedly connected to the fixed control surface 4. The two ends of the rotating shaft 9 are engaged with the rotating shaft holes of the primary moving control surface 5, which is the reference for the folding and rotation of the primary moving control surface 5. The function of the unfolding drive device 10 is to provide initial drive for the unfolding of the control surface. The unfolding drive device 10 is installed inside the rotating shaft 9. In this embodiment, it is a torsion bar. Its front end is fixedly connected to the front end of the rotating shaft 9, and its rear end is fixedly connected to the primary fixed control surface 5. When the control surface is in the folded state, the unfolding drive device 10 is in an elastic torsional deformation state. After its elastic potential energy is released from the constraint on the outside (outer wall of the control surface), it drives the primary fixed control surface 5 to unfold. After the primary fixed rudder surface 5 is fully deployed, the locking pin 12, under the action of the locking pin spring 11, will quickly pop out and insert into the locking pin hole of the fixed rudder surface 4, thereby realizing the deployment and locking of the rudder surface. The deployment and locking mechanism between the primary moving rudder surface 5 and the secondary moving rudder surface 6 is basically similar to the deployment and locking mechanism between the fixed rudder surface 4 and the primary moving rudder surface 5 (for the deployment and locking mechanism between the primary moving rudder surface 5 and the secondary moving rudder surface 6, after the secondary moving rudder surface 6 is fully deployed, the locking pin, under the action of the locking pin spring, inserts into the primary moving rudder surface 5 to achieve locking after deployment). Since the thickness of the rudder surface near the tip chord is relatively small compared to the root chord, and the rotational inertia and aerodynamic load on the secondary moving rudder surface 6 are relatively small, the size of the rotating shaft, deployment drive device, locking pin, and other parts can be reasonably reduced.

[0086] The method will be further illustrated below with examples:

[0087] Step 1: Define the overall aerodynamic configuration parameters, including the rudder length of 400 mm, the root chord length of 630 mm, the tip chord length of 140 mm, the root thickness of 40 mm, the deployment time of less than 200 ms, the tail cabin radius of 380 mm, the missile barrel radius of 440 mm, and the flight speed of 5 Mach.

[0088] Step 2: Design the folding joint according to the aerodynamic heating requirements.

[0089] According to the analysis of the aerodynamic heating environment of the aircraft flight speed and altitude, the heat insulation requirements of the folding joint are determined. The folding joint between the rudder 4 and the primary movable rudder is designed along the rudder length direction, with a gap of t1 = 0.5 mm between the two front edges, a1 = 60 mm, a2 = 182 mm. The folding joint between the primary rudder front edge 7 and the secondary movable rudder front edge 8 is designed along the rudder length direction, with a gap of t2 = 0.5 mm between the two front edges, a3 = 74 mm, a4 = 40 mm, a5 = 96.5 mm, a6 = 60 mm, a7 = 90 mm.

[0090] Step 3: Geometric design: determine the length and folding angle of the two-stage rudder according to the tail cabin outer diameter, storage box inner diameter, etc.

[0091] Referring to Figure 6 Fig. 1, the maximum design length of the primary movable rudder should satisfy 200 mm < L max < 358 mm. Taking L 1max = 310 mm, c1 = 35 mm, and c2 = 10 mm, the distance between the primary movable rudder rotation axis and the secondary movable rudder rotation axis is L1 = 210 mm. The calculation result is Taking According to the total length of the rudder, the distance between the secondary movable rudder rotation axis and the secondary movable rudder tip is L2 = 155 mm, and L 2max = 165 mm.

[0092] The calculation result is Taking

[0093] Step 4: Statics design: determine the coordination relationship between the two-stage torsion rods according to the inner wall constraints.

[0094] Referring to Figure 7 Fig. 2, the torsional moments of the two torsion rods are consistent, i.e., M1 = M2. According to the design maximum folding angle, the torsion coefficients of the two torsion rods should satisfy k1 / k2 = 14 / 108.

[0095] Step 5: Dynamics design: determine the stiffness of the two-stage torsion rods according to the deployment time requirements.

[0096] The mass of the primary movable rudder is 12.3 kg, and the rotational inertia around the rotation axis is 0.253 kg·m2 The mass of the second rudder surface is 2.8 kg, and the moment of inertia of the rotation around the rotation axis is 0.018 kg·m 2 The pre-torsion angles of the first and second rudders are both 6°. According to the torsion angle t 总 < t 设计 The torsion stiffness of the first torsion bar is k1>0.3890 N·m / rad, and k2>3.0005 N·m / rad. According to the calculation results, appropriate torsion bars are selected.

[0097] Through simulation evaluation, the folding rudder meets the requirements of stiffness and strength, and the design is completed.

[0098] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled in the art, without departing from the technical principles of the present application, several improvements and modifications can be made, and these improvements and modifications should be considered as the protection scope of the present application.

Claims

1. A design method for a high speed aircraft secondary folding rudder, characterized in that, The method comprises the following steps: Step 1: According to the overall design requirements, the design input is determined According to the flight task profile of the high-speed aircraft, the flight speed range, the flight height range and the flight attitude are determined; according to the aerodynamic requirements of the high-speed aircraft, the size, mass and moment of inertia of the rudder are determined; according to the structural space design requirements, the tail cabin outer diameter and the storage tank inner diameter and other structural dimensions are determined; according to the control requirements of the high-speed aircraft, the deployment time of the rudder is determined; Step 2: Design the folding joint according to the aerodynamic heat demand The structure of the secondary folding rudder comprises a fixed rudder (4), a first-level movable rudder (5), a second-level movable rudder (6), a first-level movable rudder leading edge (7), a second-level movable rudder leading edge (8) and two sets of deployment and locking mechanisms inside, and each set of deployment and locking mechanism comprises a torsion bar; the fixed rudder (4) is connected with the servo cabin body and the rudder of the aircraft, and drives the first-level movable rudder (5) to move through the deployment and locking mechanism, and the first-level movable rudder (5) drives the second-level movable rudder (6) to move through the other deployment and locking mechanism; there are front and rear two sets of rotating matching surfaces between the fixed rudder (4) and the first-level movable rudder (5) and between the first-level movable rudder (5) and the second-level movable rudder (6), and the connection between the two is realized through the rotating shaft (9); The folding joint gap between the first-level movable rudder leading edge (7) and the second-level movable rudder leading edge (8) is designed along the length direction of the rudder, and a t2 gap is reserved between the two leading edges; Step 3: Geometric design: according to the tail cabin outer diameter and the storage tank inner diameter, the length and folding angle of the two-level folding rudder are determined; According to the inner diameter R1 of the storage box and the outer diameter R2 of the tail cabin of the aircraft, the total length of the rudder wing is L, and h is the thickness of the folding rudder, the secondary folding rudder satisfies being retracted in the envelope size in the folded state, therefore, the maximum design length of each level of the movable rudder surface satisfies For the first level of the folding rudder, the maximum design length is L 1max =L1+a3+c1-c2, that is, the distance L1 from the rotation shaft of the first level of the folding rudder to the rotation shaft of the second level of the folding rudder, the folding seam length a3 of the second level of the folding rudder, the distance c1 between the rotation shaft of the first level of the folding rudder and the body of the missile, and the distance c2 between the rotation shaft of the second level of the folding rudder and the first level of the folding rudder; the length of the first level of the folding rudder should be greater than 1 / 2 of the total length of the rudder wing; the maximum design folding angle of the first level of the folding rudder satisfies: According to the folding seam length designed in step two, the rotation shaft position of the secondary folding rudder is determined; the maximum design length of the secondary folding rudder is L 2max =L-L1-c1+c2; the maximum folding angle of the secondary folding rudder satisfies the calculation: Step 4: Statics design: according to the inner wall constraint, the matching relationship between the two-level torsion bars is determined, the first-level torsion bar is located between the fixed rudder (4) and the first-level movable rudder (5), the second-level torsion bar is located between the first-level movable rudder (5) and the second-level movable rudder (6), and is used to provide initial driving for the corresponding first-level movable rudder (5) and second-level movable rudder (6); When the two-stage folding rudder is retracted in the storage box, the end of the two-stage folding rudder is subjected to the constraint force of the storage box, and the two-stage folding rudder wing keeps the retracted shape under the bending moment of the torsion bar; the torsional moments of the two torsion bars are M1 and M2 respectively, and the torsional coefficients are k1 and k2 respectively; according to the force analysis of the rudder wing, the torsional moments of the two torsion bars are consistent, i.e. M1=M2; the torsional coefficients of the two torsion bars satisfy Step 5: Dynamics design: according to the deployment time requirement, the stiffness of the two-level torsion bars is determined; After the rudder constraint is released, the deployment process of the secondary folding rudder is divided into two stages: in the first stage, the first-level and second-level folding rudders are deployed at the same time, and when the second-level folding rudder is deployed to be in a straight line with the first-level folding rudder, the deployment and locking mechanism between the first-level movable rudder (5) and the second-level movable rudder (6) is locked, at this time, the second stage is entered, the second-level folding rudder and the first-level folding rudder form an integral, and rotate and deploy around the first-level folding rudder rotating shaft; The dynamics equation of the first stage is: Wherein, J1 and J2 are the moment of inertia of the first and second folding rudders respectively, are the folding angles of the first and second folding rudders respectively, and the two points above indicate the second derivative. In the first stage, the dynamics equation of the second-level folding rudder is arranged as: Wherein, the second term on the right side is a constant; The deployment time of the second-level folding rudder is approximately calculated by the following formula: The dynamics equation of the second stage is: In the formula, m2 is the mass of the second-level folding rudder; Therefore, in the second stage, the deployment time of the folding rudder is calculated by the following formula: The total deployment time of the secondary folding rudder is t 总 = t1 + t2; Suppose the designed secondary folding rudder has a rudder surface deployment time of t 设计 , if t 总 < t 设计 , the stiffness of the torsion bar is determined according to t 总 , so as to obtain the secondary folding rudder meeting the design requirements.

2. The method of claim 1, wherein, In step 2, the aerodynamic heat environment of the aircraft is analyzed according to the flight speed and height of the aircraft, and the heat insulation requirement of the folding joint is determined.

3. The method of claim 1, wherein, The length of the two-level folding rudder is adjustable.

4. A secondary folding rudder designed based on the method according to any one of claims 1 to 3.

5. The structure of claim 4, wherein The unfolding and locking mechanism between the rudder surface (4) and the primary movable rudder surface (5) and between the primary movable rudder surface (5) and the secondary movable rudder surface (6) is the same; for the unfolding and locking mechanism between the rudder surface (4) and the primary movable rudder surface (5), the unfolding and locking mechanism comprises a rotating shaft (9), an unfolding driving device (10), a locking pin (12) and a locking pin compression spring (11); the rotating shaft (9) is the reference for the folding and unfolding of the rudder surface; the rotating shaft (9) penetrates through the rudder surface (4) and is fixedly connected with the rudder surface (4), the two ends of the rotating shaft (9) are matched with the rotating shaft holes of the primary movable rudder surface (5) to form the reference for the folding and unfolding of the primary movable rudder surface (5); the unfolding driving device (10) provides initial driving for the unfolding of the rudder surface; the unfolding driving device (10) is installed inside the rotating shaft (9) and is a torsion bar, the front end of which is fixedly connected with the front end of the rotating shaft (9) and the rear end of which is fixedly connected with the primary movable rudder surface (5); when the rudder surface is in the folded state, the unfolding driving device (10) is in the elastic torsional deformation state, and the elastic potential energy thereof is released after the external constraint is removed to drive the primary movable rudder surface (5) to unfold; after the primary movable rudder surface (5) is unfolded to the position, the locking pin (12) is ejected and pinned into the locking pin hole of the rudder surface (4) under the action of the locking pin compression spring (11), so that the locking of the primary movable rudder surface (5) after unfolding is realized.

6. The structure of claim 5, wherein For the unfolding and locking mechanism between the primary movable rudder surface (5) and the secondary movable rudder surface (6), after the secondary movable rudder surface (6) is unfolded to the position, the locking pin is pinned into the primary movable rudder surface (5) under the action of the locking pin compression spring, so that the locking of the secondary movable rudder surface (6) after unfolding is realized.

7. The structure of claim 5, wherein When the primary movable rudder surface is folded to the maximum angle, the secondary movable rudder surface is also folded relative to the primary movable rudder surface by a certain angle.

8. A working method of the secondary folding rudder with the structure as claimed in any one of claims 4 to 7.

9. A high-speed aircraft comprising the secondary folding rudder with the structure as claimed in any one of claims 4 to 7.

10. A working method of the high-speed aircraft as claimed in claim 9.

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