A vertical wind tunnel tail test design method for multi-control surface aircraft

Abstract

The application belongs to the field of wind tunnel test, and particularly relates to a vertical wind tunnel spin test design method for a multi-control surface aircraft. The control surfaces are classified into single-function control surfaces and multi-function control surfaces, the single-function control surfaces are classified again according to functions, and the multi-function control surfaces are weighted and distributed. Then, the single-function control surfaces and the multi-function control surfaces with the same function are combined into the same type of control surfaces to form various control surface combinations. The control surface combinations are combined with entry maneuvers and exit maneuvers to set the deflection control surfaces of the aircraft. Then, the wind tunnel spin test is performed through the set deflection control surfaces of the aircraft to obtain spin characteristics and exit characteristics data and spin exit characteristics data, and the true aircraft spin related parameters are obtained after conversion. The application provides a test design reference for the vertical wind tunnel spin test of the unconventional layout aircraft with multi-control surfaces.

Description

Technical Field

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

[0002] When 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 motions of an aircraft. Throughout history, there have been countless flight accidents caused by spins. To this day, studying the spin characteristics of an aircraft remains an important part of aircraft design. For highly maneuverable aircraft such as fighter jets, it is particularly important to clearly understand the spin characteristics. 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 the aircraft, find reasonable and feasible spin recovery methods, resolve design risks, and ensure flight safety.

[0003] As one of the few methods for studying aircraft spin characteristics, vertical wind tunnel spin testing has been widely used on various aircraft types and has proven to be highly effective. This testing allows for the prediction of actual aircraft spin characteristics and the development of spin mitigation strategies. Furthermore, vertical wind tunnel testing is low-cost and quick to conduct, enabling extensive research using a variety of pre-defined scenarios, real-time analysis of test results, and evaluation of feedback, ultimately achieving satisfactory results. Consequently, major aircraft design countries worldwide utilize vertical wind tunnel spin prediction testing when developing new aircraft.

[0004] Currently, 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 spin tests on conventional aircraft, the three control actions of pushing / pulling the stick, pedaling the rudder left / right, and pressing the stick forward / backward respectively control the elevator, rudder, and ailerons to rotate in the expected direction and deflection. The physical meaning is clear, and the actions correspond one-to-one with the control surfaces. Therefore, the aircraft can be controlled to enter / exit a spin by accurately changing the deflection of the control surfaces. However, for aircraft with multiple control surfaces, the control actions and the control surfaces do not have a single correspondence, and the control surfaces driven by three-axis control actions are complex. Therefore, conducting vertical wind tunnel spin tests on multiple control surfaces is very different from that on conventional aircraft, and it is necessary to clarify the relationship between the logic of control surface use and the aircraft's control actions. 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 this application is: a vertical wind tunnel spin test design method for multi-control surface aircraft, comprising:

[0007] First, the control surfaces are divided into single-function control surfaces and multi-function control surfaces. Then, the single-function control surfaces are further classified by function, and the multi-function control surfaces are weighted. Subsequently, the single-function control surfaces and multi-function control surfaces with the same function are combined into the same type of control surfaces to form multiple control surface combinations. All entry and recovery actions are obtained and matched with the control surface combinations as preset spin actions. According to the preset spin entry or recovery action, the aircraft's deflection control surfaces are set.

[0008] The test state of the model in the vertical wind tunnel is determined based on the aircraft's deflection surfaces, the actual aircraft's application scenarios, and the actual flight conditions. The impact of each characteristic parameter on spin is then considered, and the characteristic parameters of the test state are converted according to the dynamic similarity criterion to match the vertical wind tunnel test.

[0009] Carry out vertical wind tunnel spin tests, record spin characteristic data, record spin recovery characteristic data, and convert them back to the real aircraft according to the dynamic similarity criterion to obtain the real aircraft spin-related parameters.

[0010] Preferably, the single-function control surfaces are divided into three types of control surfaces according to their functions: pitch, yaw and roll, 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 back, and a combination of the three.

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

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

[0015] Preferably, the characteristic parameters include: forward / backward spin, configuration, weight, forward / backward 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 height, ρ mis 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 aircraft angular velocity, ω m is the model angular velocity.

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

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

[0021] This application describes a design method for vertical wind tunnel spin testing for aircraft with multiple control surfaces. This method involves classifying and combining control surfaces to obtain control surface combinations, combining these control surface combinations with entry and recovery maneuvers, and configuring the aircraft's deflected control surfaces. Wind tunnel spin testing is then conducted using these configured aircraft's deflected control surfaces to obtain spin characteristic data and spin recovery characteristic data, which are then converted to obtain real-aircraft spin-related parameters. This application provides a design reference for conducting vertical wind tunnel spin testing on aircraft with unconventional multi-control surface layouts. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions provided by this application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of this 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 clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts 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 provided, which 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: first divide the rudder surface into single function rudder surface and multi-function rudder surface, 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 according to their functions: pitch, yaw and roll, and the multi-function control surfaces are weightedly allocated according to the flight requirements of the aircraft.

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

[0031] Step S200, designing a control surface deflection strategy for a spin: obtaining all entry and exit actions, matching all entry and exit actions with control surface combinations as preset spin actions; and setting the aircraft's deflection control surfaces based on the preset spin entry or exit actions.

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

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

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

[0035] Step S300 determines the wind tunnel spin test state. The test state of the model in the vertical wind tunnel is determined based on the aircraft's deflection surfaces, the actual aircraft's application scenario, and the actual flight state. The impact of various characteristic parameters on the spin is then considered, and the characteristic parameters of the test state are converted 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 position

[0041] Linear scale

[0042] Time scale

[0043] Area scale

[0044] Linear 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 height, 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 aircraft angular velocity, ω m is the model angular velocity.

[0047] Step S400: Conduct a vertical wind tunnel spin test, record spin characteristic data, record spin recovery characteristic data, and convert them back to a real aircraft according to the dynamic similarity criterion to obtain real aircraft spin-related parameters.

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

[0049] The above design classifies and combines control surfaces to create control surface combinations. These control surface combinations are then combined with entry and recovery maneuvers to configure the aircraft's deflection control surfaces. Wind tunnel spin tests are then conducted using these deflection control surfaces to obtain spin characteristic data and spin recovery characteristic data. These data are then converted to actual aircraft spin-related parameters. This provides a design reference for conducting vertical wind tunnel spin tests on modern aircraft with unconventional control surface layouts.

[0050] As a specific implementation method, the following is described with a specific example:

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

[0052] Step S200: Design spin entry and exit methods and associate them with corresponding control surfaces. The deflection ranges for aircraft control surfaces are: 1#, 2#, 3#, and 4# deflection ranges: -30° to 30°; 5# deflection range: -35° to 35°. Taking a right spin as an example, the corresponding spin entry and exit methods and control surface deflections are shown in the following table:

[0053] Spin Entry Method

[0054]

[0055] Spin recovery methods

[0056]

[0057] In step S300, the aircraft is configured for takeoff and landing, and cruise. The simulated weights are 500kg and 800kg, respectively, with forward and aft centers of gravity. The simulated altitude for takeoff and landing is 500m, and for cruise is 3000m. The aircraft's test state is determined as shown in the table below. The actual aircraft parameters are transformed to match the dimensions of the vertical wind tunnel using the dynamic similarity criterion:

[0058]

[0059] Step S400 records spin characteristic data, including: triaxial angular velocity, angular acceleration, average angle of attack, average sideslip angle, single-turn descent height, etc.; records spin recovery characteristic data, including recovery height, recovery time, number of recovery turns, etc., and converts 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. Other structures can refer to common designs. In the absence of conflicts, 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 scope of protection 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 further classified by function, 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, and use them as preset spin actions; set the aircraft's deflection control surfaces based on the preset spin entry or recovery actions; The test state of the model in the vertical wind tunnel is determined based on the aircraft's deflection surfaces, the actual aircraft's application scenarios, and the actual flight conditions. The impact of each characteristic parameter on spin is then considered, and the characteristic parameters of the test state are converted according to the dynamic similarity criterion to match the vertical wind tunnel test. Carry out vertical wind tunnel spin tests, record spin characteristic data, record spin recovery characteristic 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 according to their functions: pitch, yaw and roll, 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: There are three types of rudder surface combinations: 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, follow stick and 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 maneuvers with 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 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: Kinetic 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 height, 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 aircraft angular velocity, 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 characteristic data include: three-axis angular velocity, angular acceleration, average angle of attack, average sideslip angle and single-circuit 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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