Ultra-low-speed rear three-point propeller aircraft full-motion horizontal tail design method and device

Abstract

The invention discloses a full-motion horizontal tail design method and device for an ultra-low-speed rear three-point propeller aircraft. The method comprises the following steps: S1, formulating a longitudinal operation stability characteristic judgment criterion; s2, selecting an initial design basic airfoil profile based on a low-speed symmetric airfoil profile and a trade-off factor; s3, designing a full-motion horizontal tail based on the initially designed basic airfoil profile; s4, the deflection angle range of the full-motion horizontal tail is determined, horizontal tail balancing angles under different cruise attack angles are calculated, whether enough control allowance is reserved or not after balancing is judged, if not, the step S2 is executed, and if yes, the step S5 is executed; and S5, calculating the longitudinal operation stability characteristic of the aircraft based on the full-motion horizontal tail, judging whether the longitudinal operation stability characteristic meets the longitudinal operation stability characteristic judgment criterion, if not, executing the step S2, and if yes, ending the design, and determining the parameters of the full-motion horizontal tail. The structural weight of the aircraft is reduced as much as possible on the basis of ensuring that the aircraft has good longitudinal maneuverability and stability.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft design, and more specifically, relates to a design method and device for a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft. Background Art

[0002] As a key aerodynamic control surface in aircraft design, the all-moving horizontal tail plays a vital role in the aircraft's maneuverability and stability. For propeller aircraft, the slipstream generated by the propeller will have a significant impact on the aircraft's aerodynamic characteristics. The propeller slipstream will change the aircraft's lift, drag and downwash characteristics, thereby affecting the aircraft's maneuverability, stability and control surface efficiency. The slipstream effect often reduces the aircraft's pitch static stability. During the design process, the influence of the propeller slipstream must be considered to ensure the aircraft's stability and maneuverability in full-profile flight. In addition, the design also needs to take into account the needs of aircraft weight reduction design, and carry out structural weight optimization and iterative design in accordance with the idea of ​​lightweight design. On the basis of ensuring that the aircraft has good longitudinal maneuverability and stability, the aircraft's structural weight is reduced as much as possible.

[0003] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to those skilled in the art. Summary of the invention

[0004] The purpose of the present invention is to provide a method and device for designing a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft, so as to reduce the structural weight of the aircraft as much as possible while ensuring that the aircraft has good longitudinal maneuverability and stability.

[0005] To achieve the above object, the present invention proposes a design method and device for a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft.

[0006] According to a first aspect of the present invention, a method for designing a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft is proposed, comprising:

[0007] S1. Formulate criteria for determining longitudinal handling stability characteristics;

[0008] S2, select the initial design basic airfoil based on the low-speed symmetric airfoil and trade-off factors;

[0009] S3. designing a fully movable horizontal tail based on the initial design basic airfoil;

[0010] S4, determining the deflection angle range of the all-movable horizontal tail, and calculating the horizontal tail trim angles at different cruise angles of attack, and judging whether there is sufficient control margin after trimming, if not, executing S2, and if yes, executing S5;

[0011] S5. Calculate the longitudinal control and stability characteristics of the aircraft based on the all-movable horizontal tail, and determine whether the longitudinal control and stability characteristics meet the longitudinal control and stability characteristics determination criteria. If not, execute S2. If yes, end the design and determine the parameters of the all-movable horizontal tail.

[0012] Optionally, the longitudinal handling stability characteristics determination criteria include:

[0013] Longitudinal static stability margin requirements, short-period and long-period motion modal response types and characteristic parameter requirements.

[0014] Optionally, the selecting of an initial design basic airfoil based on a low-speed symmetrical airfoil and trade-off factors comprises:

[0015] Calculate the lift, drag and stall characteristics of different low-speed symmetrical airfoils within a given Reynolds number range;

[0016] Based on the calculation results and the trade-off factors, a comparison and trade-off are performed to select the optimal airfoil of the all-moving horizontal tail.

[0017] Optionally, designing a fully movable horizontal tail based on the initial design basic airfoil includes:

[0018] Selecting the tailplane type of the full-moving tailplane based on weight factors;

[0019] Designing the longitudinal position of the all-movable horizontal tail on the fuselage based on the shared structural joint between the all-movable horizontal tail and the fuselage and the vertical tail;

[0020] Determine the reference value of the tail capacity of the all-moving horizontal tail and vertical tail based on engineering experience;

[0021] Determining the requirements for the horizontal and vertical tail areas and the rear fuselage length of the all-movable horizontal and vertical tail at different lateral positions of the fuselage based on the reference values ​​of the tail capacities of the all-movable horizontal and vertical tail;

[0022] estimating the total weight of the rear fuselage, the all-movable horizontal tail and the vertical tail at different lateral positions of the fuselage based on the weight coefficient;

[0023] determining a lateral position of the all-movable horizontal stabilizer on the fuselage based on the total weight;

[0024] The horizontal tail span, average chord length and tip-to-root ratio of the all-movable horizontal tail are determined based on the lateral position and longitudinal position of the all-movable horizontal tail on the fuselage, taking into account the stall characteristics of the horizontal tail, the control stability characteristics after the influence of propeller slipstream and the structural weight.

[0025] Optionally, the determining the horizontal tail span, mean chord length and tip-to-root ratio of the all-movable horizontal tail based on the lateral position and longitudinal position of the all-movable horizontal tail on the fuselage and taking into account the stall characteristics of the horizontal tail, the control stability characteristics after the influence of propeller slipstream and the structural weight comprises:

[0026] Based on the tail capacity of the all-moving horizontal tail, design the tail extension length and average chord length schemes under different aspect ratios;

[0027] Calculating the rear limit of the center of gravity under each of the schemes based on the longitudinal static stability margin requirement;

[0028] Select the solution that meets the set requirements based on the calculation results;

[0029] A reasonable range of tip-to-root ratio is selected, and the lift characteristics and structural weight of different tip-to-root ratio schemes are comprehensively considered to set the tip-to-root ratio of the all-moving horizontal tail.

[0030] Optionally, determining the deflection angle range of the full-moving horizontal stabilizer includes:

[0031] Taking the local angle of attack of the all-movable horizontal tail not exceeding the stall angle of attack of the horizontal tail when the all-movable horizontal tail is deflected during full-profile trim flight as a constraint condition, the deflection angle range of the all-movable horizontal tail is determined.

[0032] Optionally, the S5 specifically includes:

[0033] evaluating the lift characteristics, moment characteristics and stall characteristics of the all-moving horizontal tail based on the horizontal tail span, mean chord length and tip-to-root ratio of the all-moving horizontal tail;

[0034] Analyze the changes of the local speed and angle of attack of the all-moving horizontal tail under the influence of slipstream, and calculate the longitudinal static stability margin and motion modal characteristics of the aircraft;

[0035] It is determined whether the longitudinal static stability margin and motion modal characteristics of the aircraft meet the longitudinal control stability characteristics judgment criteria. If not, S2 is executed. If yes, the design is terminated and the parameters of the all-moving horizontal tail are determined.

[0036] Optionally, the setting requirements include:

[0037] Considering the influence of propeller slipstream on static stability, a margin for setting a time limit after calculating the center of gravity is reserved;

[0038] The calculation result exceeds the front limit of the center of gravity calculated according to the anti-rollover angle of the main landing gear, and retains a certain range of center of gravity variation;

[0039] The aspect ratio of the scheme is minimal.

[0040] Optionally, the weighing factors include:

[0041] The maximum lift coefficient, lift line slope, stall angle of attack, lift-to-drag ratio, whether the stall process is smooth and whether the lift line slope linearity is good.

[0042] According to a second aspect of the present invention, a fully movable horizontal tail design device for an ultra-low-speed tail-type propeller aircraft is provided, comprising:

[0043] A formulation module for formulating longitudinal handling stability characteristics determination criteria;

[0044] A selection module for selecting an initial design base airfoil based on low-speed symmetric airfoils and trade-off factors;

[0045] A design module, used for designing a fully movable horizontal tail based on the initial design basic airfoil;

[0046] a determination, calculation and judgment module, used to determine the deflection angle range of the all-moving horizontal tail, calculate the horizontal tail trim angle under different cruise angles of attack, and judge whether there is enough control margin after trimming. If not, return to the selection module; if yes, go to the judgment module;

[0047] A judgment module is used to calculate the longitudinal control and stability characteristics of the aircraft based on the all-movable horizontal tail, and judge whether the longitudinal control and stability characteristics meet the longitudinal control and stability characteristics judgment criteria. If not, return to the selection module. If yes, the design is terminated and the parameters of the all-movable horizontal tail are determined.

[0048] The beneficial effects of the present invention are as follows: the present invention formulates a longitudinal control and stability characteristic judgment criterion, designs a full-moving horizontal tail based on the longitudinal control and stability characteristic judgment criterion, ensures that the aircraft has good longitudinal maneuverability and stability, refines and clarifies the trade-off factors in the design process, makes the design process clearer, and comprehensively considers the influence of aerodynamics, control and stability, so that the weight of the aircraft tail is lighter.

[0049] The system of the present invention has other characteristics and advantages, which will be apparent from the drawings incorporated herein and the following detailed description, or will be described in detail in the drawings incorporated herein and the following detailed description, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, in which like reference numerals generally represent like components.

[0051] Figure 1 A flow chart showing the steps of a method for designing a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft according to the present invention is shown.

[0052] Figure 2 A flow chart showing the steps of a method for designing a fully moving horizontal tail of an ultra-low-speed tailwheel propeller aircraft according to a first embodiment of the present invention is shown. DETAILED DESCRIPTION

[0053] The present invention will be described in more detail below with reference to the accompanying drawings. Although preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0054] like Figure 1 As shown, a method for designing a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft according to the present invention comprises:

[0055] S1. Formulate criteria for determining longitudinal handling stability characteristics;

[0056] S2, select the initial design basic airfoil based on the low-speed symmetric airfoil and trade-off factors;

[0057] S3. Design a fully movable horizontal tail based on the initial design basic airfoil;

[0058] S4. Determine the deflection angle range of the all-moving horizontal tail, and calculate the horizontal tail trim angle at different cruise angles of attack, and judge whether there is sufficient control margin after trimming. If not, execute S2; if yes, execute S5;

[0059] S5. Calculate the longitudinal control and stability characteristics of the aircraft based on the all-movable horizontal tail, and determine whether the longitudinal control and stability characteristics meet the longitudinal control and stability characteristics judgment criteria. If not, execute S2. If yes, the design is terminated and the parameters of the all-movable horizontal tail are determined.

[0060] Specifically, the present invention formulates a longitudinal control stability characteristic judgment criterion, designs a fully movable horizontal tail based on the longitudinal control stability characteristic judgment criterion, and ensures that the aircraft has good longitudinal maneuverability and stability; selects an initial design basic airfoil from a low-speed symmetrical airfoil, and determines the optimal airfoil according to a trade-off factor; designs the basic plane size of the fully movable horizontal tail, and gives the full-moving horizontal tail up and down front and back position, span, average chord length, and tip-root ratio; determines the deflection angle limit range of the fully movable horizontal tail, and calculates the horizontal tail trim angle under different cruise angles of attack, and determines whether there is enough control margin left after trimming to preliminarily evaluate the controllability of the fully movable horizontal tail. If there is not enough control margin left, If the control margin is sufficient, the optimal airfoil is re-determined for design. If the control margin is sufficient, the longitudinal control and stability characteristics of the aircraft are calculated according to the designed full-movable horizontal tail, and it is judged whether the longitudinal control and stability characteristics meet the formulated longitudinal control and stability characteristics judgment criteria. If not, the optimal airfoil is re-determined for design until the longitudinal control and stability characteristics judgment criteria are met. If so, the design is completed and the parameters of the fully-movable horizontal tail designed this time are determined. On the basis of ensuring that the aircraft has good longitudinal controllability and stability, the present invention comprehensively considers the influence of aerodynamics, control and stability, so that the weight of the aircraft tail is lighter and the structural weight of the aircraft is reduced as much as possible.

[0061] In one example, the longitudinal handling stability characteristics determination criteria include:

[0062] Longitudinal static stability margin requirements, short-period and long-period motion modal response types and characteristic parameter requirements.

[0063] Specifically, the longitudinal static stability margin refers to the ratio of the distance between the center of gravity of the aircraft and the neutral point (the focus of the aircraft) and the average aerodynamic chord length. It is a key parameter for measuring the longitudinal static stability of the aircraft. When the aircraft has a positive longitudinal static stability margin, it means that after the aircraft is disturbed by external interference and the angle of attack changes, it can automatically generate a restoring torque to return the aircraft to its original equilibrium state. This is crucial for flight safety, especially in the cruise, take-off and landing phases, and can effectively prevent dangerous situations such as stalling of the aircraft. Short-period motion is a major mode of longitudinal motion of the aircraft, which is mainly manifested as rapid oscillation changes in the pitch angle and angle of attack of the aircraft. It is mainly determined by the pitch damping and pitch stiffness of the aircraft. Long-period motion is also called sinking and floating motion, which mainly involves the slow changes in the altitude and speed of the aircraft. It is caused by the imbalance between the gravity and lift of the aircraft, and is usually manifested as periodic changes in the altitude and speed of the aircraft, which are much slower than short-period motion.

[0064] In one example, selecting an initial design base airfoil based on a low-speed symmetric airfoil and trade-off factors includes:

[0065] Calculate the lift, drag and stall characteristics of different low-speed symmetrical airfoils within a given Reynolds number range;

[0066] Based on the calculation results and trade-off factors, the optimal airfoil of the full-moving horizontal tail is selected.

[0067] In one example, designing a full-moving horizontal tail based on an initial design base airfoil includes:

[0068] Based on weight factors, the horizontal tail type of the full-moving horizontal tail is selected;

[0069] The longitudinal position of the all-movable horizontal tail on the fuselage is designed based on the shared structural joints between the all-movable horizontal tail and the fuselage and vertical tail.

[0070] Determine the reference values ​​of the tail capacity of the all-moving horizontal and vertical tail based on engineering experience;

[0071] Based on the reference values ​​of the tail capacity of the all-movable horizontal tail and vertical tail, the requirements of the horizontal and vertical tail area and the length of the rear fuselage of the all-movable horizontal tail and vertical tail at different lateral positions of the fuselage are determined;

[0072] Estimate the total weight of the rear fuselage, the all-movable horizontal tail and the vertical tail at different lateral positions of the fuselage based on the weight coefficient;

[0073] Determine the lateral position of the all-movable horizontal stabilizer on the fuselage based on the gross weight;

[0074] Based on the lateral and longitudinal positions of the all-moving horizontal tail on the fuselage, the horizontal tail span, average chord length and tip-to-root ratio of the all-moving horizontal tail are determined taking into account the stall characteristics of the horizontal tail, the control stability characteristics after the influence of propeller slipstream and the structural weight.

[0075] In one example, based on the lateral and longitudinal positions of the all-movable horizontal tail on the fuselage, the horizontal tail stall characteristics, the control stability characteristics after the influence of the propeller slipstream, and the structural weight, the horizontal tail span, the average chord length, and the tip-to-root ratio of the all-movable horizontal tail are determined, including:

[0076] Based on the tail capacity of the all-moving horizontal tail, the horizontal tail span and average chord length schemes under different aspect ratios are designed;

[0077] Calculate the rear limit of the center of gravity under each scheme based on the longitudinal static stability margin requirements;

[0078] Select the solution that meets the set requirements based on the calculation results;

[0079] Select a reasonable range of tip-to-root ratio, comprehensively consider the lift characteristics and structural weight of different tip-to-root ratio schemes, and set the tip-to-root ratio of the full-moving horizontal tail.

[0080] In one example, determining the deflection angle range of the full-motion horizontal stabilizer includes:

[0081] The deflection angle range of the all-movable horizontal tail is determined by taking the local angle of attack not exceeding the stall angle of attack of the horizontal tail when the all-movable horizontal tail is deflected during full-profile balanced flight as a constraint condition.

[0082] In an example, S5 specifically includes:

[0083] The lift characteristics, moment characteristics and stall characteristics of the full-moving horizontal tail are evaluated based on its horizontal tail span, mean chord length and tip-to-root ratio;

[0084] Analyze the changes of local speed and angle of attack of the all-moving horizontal tail under the influence of slipstream, and calculate the longitudinal static stability margin and motion modal characteristics of the aircraft;

[0085] Determine whether the aircraft's longitudinal static stability margin and motion modal characteristics meet the longitudinal control stability characteristics judgment criteria. If not, execute S2. If yes, the design ends and the parameters of the all-moving horizontal tail are determined.

[0086] In one example, setting requirements includes:

[0087] Considering the effect of propeller slipstream on static stability, a time-limited margin is reserved after calculating the center of gravity;

[0088] The calculation result exceeds the front limit of the center of gravity calculated according to the anti-rollover angle of the main landing gear, and retains a certain range of center of gravity variation;

[0089] The aspect ratio of the scheme is the smallest.

[0090] In one example, the trade-offs include:

[0091] The maximum lift coefficient, lift line slope, stall angle of attack, lift-to-drag ratio, whether the stall process is smooth and whether the lift line slope linearity is good.

[0092] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but is not intended to be limiting of the present invention. It should be noted that the embodiments and features in the embodiments of the present invention may be combined with each other without conflict.

[0093] Embodiment 1

[0094] like Figure 2 As shown, this embodiment provides a method for designing a fully moving horizontal tail of an ultra-low-speed tail-wheel propeller aircraft, comprising:

[0095] Step 1: Formulate the criteria for determining longitudinal control stability characteristics. The criteria for determining longitudinal control stability characteristics should clearly define the requirements for longitudinal static stability margin. The longitudinal static stability margin at the rear limit of the center of gravity after the influence of the superimposed slipstream can be selected as a requirement of not less than 10%; clarify the requirements for the types and characteristic parameters of short-period and long-period motion modal responses, and refer to the first-level flight quality requirements of the manned aircraft flight quality specification as constraints.

[0096] Step 2: Select the initial design basic airfoil from the low-speed symmetrical airfoils. You can choose NACA series airfoils, such as NACA0009, NACA0012, etc., calculate the lift-drag characteristics and stall characteristics of different airfoils within a given Reynolds number range, compare and weigh the calculation results to select the optimal airfoil. The weighing factors include the maximum lift coefficient, lift line slope, stall angle of attack, lift-to-drag ratio, whether the stall process is gentle, and whether the lift line slope linearity is good.

[0097] Step 3: Design the basic plane dimensions of the all-moving horizontal tail, and give the up-down, fore-and-aft position, span, average chord length, and tip-to-root ratio of the all-moving horizontal tail.

[0098] Step 3-1, determine the up and down front and back positions of the all-moving horizontal tail by combining the tail capacity method and weight optimization results. First, consider the weight factor to select the horizontal tail form, avoid the cross tail and T-tail, and choose the form of sharing the structural joints with the fuselage and vertical tail to design the up and down positions of the horizontal tail. Secondly, set the reference value of the tail capacity of the horizontal tail and vertical tail according to engineering experience. The tail capacity should be determined based on the size of the aircraft wing area. 0.5 can be selected. Then, adjust it appropriately according to the static stability results to obtain the horizontal tail area and rear fuselage length requirements at different front and back positions of the horizontal vertical tail. Use the weight coefficient to estimate the weight of the rear fuselage and horizontal vertical tail at different front and back positions of the horizontal vertical tail. Compare the weight results at different front and back positions, and select the lightest weight solution to design the horizontal tail layout solution.

[0099] Step 3-2: Based on the horizontal tail position designed in step 3-1, the horizontal tail stall characteristics, the control characteristics after the influence of propeller slipstream, and the structural weight are comprehensively considered to determine the horizontal tail extension, average chord length, and tip-to-root ratio. Referring to the horizontal tail tail capacity in step 3-1, the horizontal tail extension and average chord length schemes under different aspect ratios are designed. The aspect ratio can be selected from 3 to 7. According to the static stability margin requirements in step 1, the rear limit of the center of gravity under different schemes is calculated. The influence of propeller slipstream on static stability should be considered in the calculation, and a certain margin can be reserved. A margin of 3% to 5% can be selected. The calculation result should exceed the front limit of the center of gravity calculated according to the anti-rollover angle of the main landing gear, and a certain range of center of gravity variation should be reserved. Among the schemes that meet the requirements, a scheme with a relatively smaller aspect ratio is selected. A reasonable tip-to-root ratio range can be selected, which can be 0.4 to 0.7. Considering the lift characteristics and structural weight of different tip-to-root ratio schemes comprehensively, the tip-to-root ratio of the horizontal tail is set.

[0100] Step 4: Determine the deflection angle limit range of the all-moving horizontal stabilizer and preliminarily evaluate the controllability of the all-moving horizontal stabilizer.

[0101] Step 4-1. According to the constraint condition that the local angle of attack of the fully movable horizontal tail does not exceed the horizontal tail stall angle of attack during the fully trimmed flight, the deflection angle range of the fully movable horizontal tail is determined;

[0102] Step 4-2, calculate the horizontal tail trim angle at different cruise angles of attack, and determine whether there is sufficient control margin after trimming. The control margin at the maximum / minimum angle of attack can be selected to be no less than 3°~5°. If not, return to step 2; if yes, proceed to step 5.

[0103] Step 5, aerodynamic and control stability characteristics verification and confirmation. Based on the fully movable horizontal tail determined in step 3-2, evaluate the lift characteristics, torque characteristics, and stall characteristics of the horizontal tail, analyze the changes in the local speed and angle of attack of the horizontal tail under the influence of slipstream, calculate the longitudinal static stability margin and motion modal characteristics of the aircraft, and determine whether the criteria requirements of step 1 are met. If so, the design is completed. If not, return to step 2.

[0104] Embodiment 2

[0105] This embodiment provides a fully movable horizontal tail design device for an ultra-low-speed tail-type propeller aircraft, comprising:

[0106] A formulation module for formulating longitudinal handling stability characteristics determination criteria;

[0107] A selection module for selecting an initial design base airfoil based on low-speed symmetric airfoils and trade-off factors;

[0108] Design module, used to design a fully movable horizontal tail based on the initial design basic airfoil;

[0109] The determination, calculation and judgment module is used to determine the deflection angle range of the full-moving horizontal tail, calculate the horizontal tail trim angle under different cruise angles of attack, and judge whether there is enough control margin after trimming. If not, return to the selection module, if yes, go to the judgment module;

[0110] The judgment module is used to calculate the longitudinal control and stability characteristics of the aircraft based on the full-moving horizontal tail, and judge whether the longitudinal control and stability characteristics meet the longitudinal control and stability characteristics judgment criteria. If not, it returns to the selection module. If so, the design ends and the parameters of the full-moving horizontal tail are determined.

[0111] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for designing a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft, characterized in that: include: S1. Formulate criteria for determining longitudinal handling characteristics; S2, select the initial design basic airfoil based on the low-speed symmetric airfoil and trade-off factors; S3. designing a fully movable horizontal tail based on the initial design basic airfoil; S4, determining the deflection angle range of the all-movable horizontal tail, and calculating the horizontal tail trim angles at different cruise angles of attack, and judging whether there is sufficient control margin after trimming, if not, executing S2, and if yes, executing S5; S5. Calculate the longitudinal control and stability characteristics of the aircraft based on the all-movable horizontal tail, and determine whether the longitudinal control and stability characteristics meet the longitudinal control and stability characteristics determination criteria. If not, execute S2. If yes, end the design and determine the parameters of the all-movable horizontal tail.

2. The method for designing a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft according to claim 1, characterized in that: The longitudinal handling stability characteristics determination criteria include: Longitudinal static stability margin requirements, short-period and long-period motion modal response types and characteristic parameter requirements.

3. The method for designing a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft according to claim 2, characterized in that: The selection of the initial design basic airfoil based on the low-speed symmetrical airfoil and trade-off factors includes: Calculate the lift, drag and stall characteristics of different low-speed symmetrical airfoils within a given Reynolds number range; Based on the calculation results and the trade-off factors, a comparison and trade-off are performed to select the optimal airfoil of the all-moving horizontal tail.

4. The method for designing a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft according to claim 3, characterized in that: The design of a fully movable horizontal tail based on the initial design basic airfoil comprises: Selecting the tailplane type of the full-moving tailplane based on weight factors; Designing the longitudinal position of the all-movable horizontal tail on the fuselage based on the shared structural joint between the all-movable horizontal tail and the fuselage and the vertical tail; Determine the reference value of the tail capacity of the all-moving horizontal tail and vertical tail based on engineering experience; Determining the requirements for the horizontal and vertical tail areas and the rear fuselage length of the all-movable horizontal and vertical tail at different lateral positions of the fuselage based on the reference values ​​of the tail capacities of the all-movable horizontal and vertical tail; estimating the total weight of the rear fuselage, the all-movable horizontal tail and the vertical tail at different lateral positions of the fuselage based on the weight coefficient; determining a lateral position of the all-movable horizontal stabilizer on the fuselage based on the total weight; The horizontal tail span, average chord length and tip-to-root ratio of the all-movable horizontal tail are determined based on the lateral position and longitudinal position of the all-movable horizontal tail on the fuselage, taking into account the stall characteristics of the horizontal tail, the control stability characteristics after the influence of propeller slipstream and the structural weight.

5. The method for designing a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft according to claim 4, characterized in that: Determining the horizontal tail span, average chord length and tip-to-root ratio of the all-movable horizontal tail based on the lateral position and longitudinal position of the all-movable horizontal tail on the fuselage and taking into account the stall characteristics of the horizontal tail, the control stability characteristics after the influence of the propeller slipstream and the structural weight includes: Based on the tail capacity of the all-moving horizontal tail, design the tail extension length and average chord length schemes under different aspect ratios; Calculating the rear limit of the center of gravity under each of the schemes based on the longitudinal static stability margin requirement; Select the solution that meets the set requirements based on the calculation results; A reasonable range of tip-to-root ratio is selected, and the lift characteristics and structural weight of different tip-to-root ratio schemes are comprehensively considered to set the tip-to-root ratio of the all-moving horizontal tail.

6. The method for designing a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft according to claim 1, characterized in that: Determining the deflection angle range of the full-moving horizontal tail comprises: Taking the local angle of attack of the all-movable horizontal tail not exceeding the stall angle of attack of the horizontal tail when the all-movable horizontal tail is deflected during full-profile trim flight as a constraint condition, the deflection angle range of the all-movable horizontal tail is determined.

7. The method for designing a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft according to claim 5, characterized in that: The S5 specifically includes: evaluating the lift characteristics, moment characteristics and stall characteristics of the all-moving horizontal tail based on the horizontal tail span, mean chord length and tip-to-root ratio of the all-moving horizontal tail; Analyze the changes of the local speed and angle of attack of the all-moving horizontal tail under the influence of slipstream, and calculate the longitudinal static stability margin and motion modal characteristics of the aircraft; It is determined whether the longitudinal static stability margin and motion modal characteristics of the aircraft meet the longitudinal control stability characteristics judgment criteria. If not, S2 is executed. If yes, the design is terminated and the parameters of the all-moving horizontal tail are determined.

8. The method for designing a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft according to claim 5, characterized in that: The setting requirements include: Considering the influence of propeller slipstream on static stability, a margin for setting a time limit after calculating the center of gravity is reserved; The calculation result exceeds the front limit of the center of gravity calculated according to the anti-rollover angle of the main landing gear, and retains a certain range of center of gravity variation; The aspect ratio of the scheme is minimal.

9. The method for designing a fully movable horizontal tail of an ultra-low-speed tail-wheel propeller aircraft according to claim 3, characterized in that: The trade-offs include: The maximum lift coefficient, lift line slope, stall angle of attack, lift-to-drag ratio, whether the stall process is smooth and whether the lift line slope linearity is good.

10. A fully movable horizontal tail design device for an ultra-low speed tail-wheel propeller aircraft, characterized in that: include: A formulation module for formulating longitudinal handling stability characteristics determination criteria; A selection module for selecting an initial design base airfoil based on low-speed symmetric airfoils and trade-off factors; A design module is used to design a full-moving horizontal tail based on the initial design basic airfoil; a determination, calculation and judgment module, used to determine the deflection angle range of the all-moving horizontal tail, calculate the horizontal tail trim angle under different cruise angles of attack, and judge whether there is enough control margin after trimming. If not, return to the selection module; if yes, go to the judgment module; A judgment module is used to calculate the longitudinal control and stability characteristics of the aircraft based on the all-movable horizontal tail, and judge whether the longitudinal control and stability characteristics meet the longitudinal control and stability characteristics judgment criteria. If not, return to the selection module. If yes, the design is terminated and the parameters of the all-movable horizontal tail are determined.

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