Vertical wind tunnel tail rotation test design method for multi-control-surface aircraft

Abstract

The invention belongs to the field of wind tunnel tests, and particularly relates to a vertical wind tunnel tail rotation test design method for a multi-control-surface aircraft, and the method comprises the steps: classifying control surfaces, dividing the control surfaces into single-function control surfaces and multifunctional control surfaces, then carrying out the re-classification of the functions of the single-function control surfaces, and carrying out the weighted distribution of the multifunctional control surfaces; then, single-function control surfaces and multifunctional control surfaces with the same function are combined into control surfaces of the same type to form multiple control surface combinations, the control surface combinations are combined with entering actions and changing actions, deflection control surfaces of the aircraft are arranged, and then a wind tunnel tail spin test is conducted through the arranged deflection control surfaces of the aircraft. And obtaining tail rotation characteristics, modified characteristic data and tail rotation modified characteristic data, and performing conversion to obtain real tail rotation related parameters. According to the invention, a test design reference is provided for carrying out a vertical wind tunnel tail spin test on an unconventional layout aircraft with multiple control surfaces.

Description

Technical Field

[0001] The present application belongs to the field of wind tunnel testing, and in particular relates to a vertical wind tunnel tailspin test design method for multi-control surface aircraft. Background Art

[0002] After an aircraft flies above the stall angle of attack, it often deviates, rotates, and gradually develops into a spin. A spin is one of the most dangerous uncontrolled movements of an aircraft. Historically, there have been countless flight accidents caused by spins. To this day, studying the spin characteristics of an aircraft is still an important part of aircraft design. For highly maneuverable aircraft such as fighter jets, it is particularly important to study the spin characteristics clearly. In order to study the spin characteristics of an aircraft, vertical wind tunnel spin tests and atmospheric model free flight tests are often used in the modern aircraft design process to study the spin characteristics of an aircraft, find reasonable and feasible spin recovery methods, resolve design risks, and ensure flight safety.

[0003] As one of the few means to study the spin characteristics of aircraft, vertical wind tunnel spin tests have been widely used in various types of aircraft and have been proven to be effective. Through this test, the spin characteristics of the real aircraft can be predicted and methods for correcting the spin can be studied. In addition, vertical wind tunnel tests are low-cost and short-term. A large number of studies can be conducted by presetting multiple schemes, and the test results can be analyzed in real time, and evaluation opinions can be given to achieve reasonable and satisfactory results. Therefore, the major countries in the world with aircraft design capabilities basically use vertical wind tunnels to conduct spin prediction tests when developing new aircraft.

[0004] At present, with the development of aviation technology and the update of mission requirements, there are more and more aircraft with multi-control surface layouts. When conducting vertical wind tunnel tailspin tests on conventionally configured aircraft, the three control actions of pushing / pulling the stick, left / right rudder pedaling, and forward / reverse pressure on the stick respectively control the elevator, rudder, and aileron to rotate in the expected direction and deflection. The physical meaning is clear, and the actions correspond to the control surfaces one by one, so that the aircraft can be controlled to enter / exit the tailspin by accurately changing the deflection of the control surfaces. However, for aircraft with multiple control surfaces, the control actions and the control surfaces are not a single corresponding relationship, and the control surfaces driven by three-axis control actions are complicated. Therefore, conducting vertical wind tunnel tailspin tests on multiple control surfaces is very different from that of conventional aircraft, and it is necessary to clarify the relationship between the logic of the use of the control surfaces and the control actions of the aircraft. Summary of the invention

[0005] The purpose of this application is to provide a vertical wind tunnel spin test design method for multi-control surface aircraft, so as to solve the problem that it is difficult to clarify the relationship between the control surface usage logic and the aircraft's control actions when conducting existing vertical wind tunnel spin tests.

[0006] The technical solution of the present application is: a vertical wind tunnel tailspin test design method for multi-control surface aircraft, comprising:

[0007] First, the rudder surfaces are divided into single-function rudder surfaces and multi-function rudder surfaces, and then the single-function rudder surfaces are reclassified by function, and the multi-function rudder surfaces are weightedly allocated; then, the single-function rudder surfaces and multi-function rudder surfaces with the same function are combined into the same type of rudder surfaces, forming a variety of rudder surface combinations;

[0008] Obtain all entry and recovery actions, match all entry and recovery actions with control surface combinations as preset spin actions; set the aircraft's deflection control surfaces according to the preset spin entry or recovery actions;

[0009] The test state of the model in the vertical wind tunnel is determined according to the aircraft's deflection control surfaces, the application scenarios of the real aircraft and the actual flight state; then, the influence of various characteristic parameters on the spin is considered, and each characteristic parameter of the test state is converted according to the dynamic similarity criterion to match the vertical wind tunnel test; a vertical wind tunnel spin test is carried out, and the spin characteristics and recovery characteristics data are recorded, and the spin recovery characteristics data are recorded, and then converted back to the real aircraft according to the dynamic similarity criterion to obtain the spin-related parameters of the real aircraft.

[0010] Preferably, the single-function control surfaces are divided into three types of control surfaces, namely pitch, yaw and roll, according to their functions, and the multi-function control surfaces are weightedly allocated according to the flight requirements of the aircraft.

[0011] Preferably, the control surface combination includes three types: a pitch control surface combination, a yaw control surface combination and a roll control surface combination.

[0012] Preferably, all entry actions include pulling the stick, pushing the rudder, pushing the stick against the ground, and a combination of the three.

[0013] Preferably, all recovery actions are push stick, back rudder and follow stick and a combination of the three.

[0014] Preferably, the specific method of matching all entry actions and recovery operations with the rudder surface combination is: matching the push / pull rod with the pitch rudder surface combination, matching the pedal / anti-pedal rudder with the yaw rudder surface combination, and matching the forward / reverse pressure rod with the roll rudder surface combination.

[0015] Preferably, the characteristic parameters include: forward / backward flight spin, configuration, weight, forward / rearward center of gravity, moment of inertia and flight altitude.

[0016] Preferably, the kinetic similarity criteria include:

[0017]

[0018] Where K is the scaling factor, and the atmospheric density ratio Δ=ρ f / ρ m , ρ f is the atmospheric density at the simulated altitude, ρm is the atmospheric density at the altitude of the wind tunnel; subscript f represents the aircraft, m represents the model, and cg represents the center of mass; m m is the model mass, m f is the aircraft mass; I f is the aircraft moment of inertia, I m is the model moment of inertia, X cg is the center of mass position, C A represents the average aerodynamic chord length of the aircraft; l f is the linear scale of the aircraft, l m is the model linear scale, t f is the aircraft time scale, t m is the model time scale, S f is the aircraft area scale, S m is the model area scale, V f is the linear velocity of the aircraft, V m is the model linear velocity, ω f is the angular velocity of the aircraft, ω m is the model angular velocity.

[0019] Preferably, the spin characteristics and recovery characteristics data include: three-axis angular velocity, angular acceleration, average angle of attack, average sideslip angle and single-lap descent height.

[0020] Preferably, the spin recovery characteristic data includes recovery height, recovery time and recovery number of circles.

[0021] The vertical wind tunnel tailspin test design method for multi-control surface aircraft of the present application is to obtain a rudder surface combination by classifying and combining the rudder surfaces, combining the rudder surface combination with the entry action and the recovery action, setting the deflection rudder surface of the aircraft, and then conducting a wind tunnel tailspin test with the set deflection rudder surface of the aircraft to obtain tailspin characteristics and recovery characteristics data as well as tailspin recovery characteristics data, and converting the data to obtain the real aircraft tailspin related parameters. The present application provides an experimental design reference for conducting vertical wind tunnel tailspin tests on aircraft with unconventional layouts with multiple control surfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution provided by the present application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present application.

[0023] Figure 1 This is a schematic diagram of the overall process of this application;

[0024] Figure 2 This is a schematic diagram of the rudder surface combination and classification for this application. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] A vertical wind tunnel spin test design method for aircraft with multiple control surfaces is used to carry out vertical wind tunnel spin tests on aircraft with multiple control surfaces.

[0027] like Figure 1 , including the following steps:

[0028] Step S100, rudder surface combination and classification: firstly, the rudder surfaces are divided into single-function rudder surfaces and multi-function rudder surfaces, such as Figure 2 , and then reclassify the single-function rudder surfaces by function, and perform weighted allocation on the multi-function rudder surfaces; then combine the single-function rudder surfaces and the multi-function rudder surfaces with the same function into the same type of rudder surfaces, forming a variety of rudder surface combinations.

[0029] Preferably, the single-function control surfaces are divided into three types of control surfaces, namely pitch, yaw and roll, according to their functions, and the multi-function control surfaces are weightedly allocated according to the flight requirements of the aircraft.

[0030] In this way, the control surface combination includes three types: pitch control surface combination, yaw control surface combination and roll control surface combination.

[0031] Step S200, designing a control surface deflection strategy for a tailspin: obtaining all entry actions and recovery actions, matching all entry actions and recovery actions with control surface combinations as preset tailspin actions; and setting the aircraft's deflection control surfaces according to the preset tailspin entry action or recovery action.

[0032] Preferably, all entry actions include pulling the stick, pushing the rudder, pushing the stick against the ground, and a combination of the three.

[0033] All recovery actions are push stick, reverse rudder and follow stick, as well as a combination of the three.

[0034] Preferably, the specific method of matching all entry actions and recovery operations with the rudder surface combination is: matching the push / pull rod with the pitch rudder surface combination, matching the pedal / anti-pedal rudder with the yaw rudder surface combination, and matching the forward / reverse pressure rod with the roll rudder surface combination.

[0035] Step S300, determine the wind tunnel tailspin test state. Determine the test state of the model in the vertical wind tunnel according to the deflection control surface of the aircraft, the application scenario of the real aircraft and the actual flight state; then consider the influence of each characteristic parameter on the tailspin, and convert each characteristic parameter of the test state according to the dynamic similarity criterion to match the vertical wind tunnel test.

[0036] Preferably, the characteristic parameters include: forward / backward flight spin, configuration, weight, front / rear center of gravity, moment of inertia, flight altitude, etc.

[0037] Preferably, the kinetic similarity criterion is as follows:

[0038] quality

[0039] Moment of Inertia

[0040] Center of mass location

[0041] Linear scale

[0042] Time scale

[0043] Area scale

[0044] Line speed

[0045] Angular velocity

[0046] Where K is the scaling factor, and the atmospheric density ratio Δ=ρ f / ρ m , ρ f is the atmospheric density at the simulated altitude, ρ m is the atmospheric density at the altitude of the wind tunnel. The subscript f represents the aircraft, m represents the model, and cg represents the center of mass; m m is the model mass, m f is the aircraft mass; I f is the aircraft moment of inertia, I m is the model moment of inertia, X cg is the center of mass position, C A represents the average aerodynamic chord length of the aircraft; l f is the linear scale of the aircraft, l m is the model linear scale, t f is the aircraft time scale, t m is the model time scale, S f is the aircraft area scale, S m is the model area scale, V f is the linear velocity of the aircraft, Vm is the model linear velocity, ω f is the angular velocity of the aircraft, ω m is the model angular velocity.

[0047] Step S400, conducting a vertical wind tunnel spin test, recording spin characteristics and recovery characteristics data, recording spin recovery characteristics data, and converting them back to a real aircraft according to a dynamic similarity criterion to obtain real aircraft spin-related parameters.

[0048] Preferably, the spin characteristics and recovery characteristics data include: three-axis angular velocity, angular acceleration, average angle of attack, average sideslip angle, single-turn descent height, etc. The spin recovery characteristics data include parameters such as recovery height, recovery time, and number of recovery turns.

[0049] Through the above design, the control surfaces are classified and combined to obtain the control surface combination, the control surface combination is combined with the entry action and the recovery action, the deflection control surface of the aircraft is set, and then the wind tunnel tail spin test is carried out through the set aircraft deflection control surface, the tail spin characteristics and recovery characteristics data and tail spin recovery characteristics data are obtained, and the real aircraft tail spin related parameters are obtained after conversion. It provides an experimental design reference for conducting vertical wind tunnel tail spin tests on modern aircraft with unconventional layouts with multiple control surfaces.

[0050] As a specific implementation method, a specific example is used to illustrate:

[0051] Step S100, the control surfaces of a certain multi-control surface aircraft are numbered 1#, 2#, 3#, 4#, and 5#, wherein the 1#, 2#, and 3# control surfaces are used for pitch control, 50% of the authority of the 4# control surface is used for pitch, and 50% of the authority is used for yaw; the 5# control surface is used for roll control, and after the control surfaces are recombined, the combination of the control surfaces for pitch function is: 1#+2#+3#+50%4#; the combination of the control surfaces for roll function is: 5#; and the combination of the control surfaces for yaw function is: 50%4#.

[0052] Step S200, design the methods for entering and exiting a tailspin, and associate them with the corresponding control surfaces. The deflection ranges of the aircraft control surfaces are: 1#, 2#, 3#, 4# deflection range: -30°~30°; 5# deflection range: -35°~35°; taking a right tailspin as an example, the corresponding methods for entering and exiting a tailspin and the deflection of the control surfaces are shown in the following table:

[0053] Spin Entry Method

[0054]

[0055] Spin recovery methods

[0056]

[0057] Step S300, the aircraft is divided into two configurations: take-off and landing, and cruise. The simulated typical weights are 500kg and 800kg respectively, and the front and rear centers of gravity are; the simulated altitude of the take-off and landing configuration is 500m, and the simulated altitude of the cruise configuration is 3000m. The test state of the aircraft is determined as shown in the following table, and the real aircraft parameters are transformed to match the size of the vertical wind tunnel according to the dynamic similarity criterion:

[0058]

[0059] Step S400, record the spin characteristics and recovery characteristics data, including: three-axis angular velocity, angular acceleration, average angle of attack, average sideslip angle, single-turn descent height, etc.; record the spin recovery characteristics data, including recovery height, recovery time, number of recovery turns, etc., and convert them to the real aircraft according to the dynamic similarity criterion. The details are shown in the following table:

[0060]

[0061]

[0062] Finally, it should be noted that: the drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0063] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A vertical wind tunnel spin test design method for a multi-control surface aircraft, characterized in that: include: First, the rudder surfaces are divided into single-function rudder surfaces and multi-function rudder surfaces, and then the single-function rudder surfaces are reclassified according to their functions, and the multi-function rudder surfaces are weighted and allocated; Subsequently, single-function rudder surfaces and multi-function rudder surfaces with the same function are combined into the same type of rudder surfaces, forming a variety of rudder surface combinations; Obtain all entry and recovery actions, match all entry and recovery actions with control surface combinations as preset spin actions; set the aircraft's deflection control surfaces according to the preset spin entry or recovery actions; The test state of the model in the vertical wind tunnel is determined according to the aircraft's deflection control surface, the application scenario of the real aircraft and the actual flight state; then, considering the influence of each characteristic parameter on the tailspin, each characteristic parameter of the test state is converted according to the dynamic similarity criterion to match the vertical wind tunnel test; Carry out vertical wind tunnel spin tests, record the spin characteristics and recovery characteristics data, record the spin recovery characteristics data, and convert them back to the real aircraft according to the dynamic similarity criterion to obtain the real aircraft spin-related parameters.

2. The vertical wind tunnel spin test design method for a multi-control surface aircraft according to claim 1, characterized in that: The single-function control surfaces are divided into three types of control surfaces: pitch, yaw and roll according to their functions, and the multi-function control surfaces are weightedly allocated according to the flight requirements of the aircraft.

3. The vertical wind tunnel spin test design method for a multi-control surface aircraft according to claim 1, characterized in that: The rudder surface combinations include three types: pitch rudder surface combination, yaw rudder surface combination and roll rudder surface combination.

4. The vertical wind tunnel spin test design method for a multi-control surface aircraft according to claim 1, characterized in that: All entry actions include pulling the stick, pushing the rudder, pushing the stick back, and a combination of the three.

5. The vertical wind tunnel spin test design method for a multi-control surface aircraft according to claim 4, characterized in that: All recovery actions are push stick, reverse rudder and follow stick, as well as a combination of the three.

6. The vertical wind tunnel spin test design method for a multi-control surface aircraft according to claim 5, characterized in that: The specific method for matching all entry and recovery operations with the control surface combinations is to match the push / pull stick with the pitch control surface combination, match the pedal / anti-pedal stick with the yaw control surface combination, and match the forward / backward pressure stick with the roll control surface combination.

7. The vertical wind tunnel spin test design method for a multi-control surface aircraft according to claim 1, characterized in that: Characteristic parameters include: forward / backward flight spin, configuration, weight, forward / backward center of gravity, moment of inertia and flight altitude.

8. The vertical wind tunnel spin test design method for a multi-control surface aircraft according to claim 1, characterized in that: The dynamic similarity criteria include: Where K is the scaling factor, and the atmospheric density ratio Δ=ρ f / ρ m , ρ f is the atmospheric density at the simulated altitude, ρ m is the atmospheric density at the altitude of the wind tunnel; subscript f represents the aircraft, m represents the model, and cg represents the center of mass; m m is the model mass, m f is the aircraft mass; I f is the aircraft moment of inertia, I m is the model moment of inertia, X cg is the center of mass position, C A represents the average aerodynamic chord length of the aircraft; l f is the linear scale of the aircraft, l m is the model linear scale, t f is the aircraft time scale, t m is the model time scale, S f is the aircraft area scale, S m is the model area scale, V f is the linear velocity of the aircraft, V m is the model linear velocity, ω f is the angular velocity of the aircraft, ω m is the model angular velocity.

9. The vertical wind tunnel spin test design method for a multi-control surface aircraft according to claim 1, characterized in that: The spin and recovery characteristics data include: three-axis angular velocity, angular acceleration, average angle of attack, average sideslip angle and single-lap descent height.

10. The vertical wind tunnel spin test design method for a multi-control surface aircraft according to claim 1, characterized in that: The spin recovery characteristic data include recovery altitude, recovery time and number of recovery turns.

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