A method for determining a sideslip angle correction amount of a pitch moment coefficient of a propeller aircraft

Abstract

The application belongs to the technical field of propeller aircraft control, and particularly relates to a method for determining a sideslip angle correction amount of a pitch moment coefficient of a propeller aircraft, comprising the following steps: step one, calculating a propeller parameter β0; step two, based on the propeller parameter β0, calculating a derivative C Yβ ' of a side force coefficient defined based on a propeller rotating speed and a diameter with respect to a sideslip angle; step three, based on the propeller parameter β0 and the derivative C Yβ ' of the side force coefficient defined based on the propeller rotating speed and the diameter with respect to the sideslip angle, calculating a pitch moment coefficient derivative based on an incoming flow speed pressure and a wing reference area; and step four, calculating the sideslip angle correction amount ΔC m of the pitch moment coefficient based on the pitch moment coefficient derivative based on the incoming flow speed pressure and the wing reference area.

Description

Technical Field

[0001] This application belongs to the field of propeller aircraft control technology, specifically relating to a method for determining the sideslip angle correction amount of the pitch moment coefficient of a propeller aircraft. Background Technology

[0002] The pitching moment of a propeller-driven aircraft is affected not only by the propeller slipstream and the normal force of the propeller disk, but also by the lateral force of the propeller.

[0003] When landing in strong crosswinds, the pitch moment of a propeller-driven aircraft will change significantly. In order to correctly control the pitch attitude angle of the aircraft and ensure landing safety, it is necessary to accurately determine the sideslip angle correction amount of the aircraft pitch moment coefficient.

[0004] Currently, there is a lack of a method to quickly and accurately determine the sideslip angle correction for the pitch moment coefficient of an aircraft, in order to support safe handling of propeller aircraft landing in strong crosswinds. Therefore, this application is made. Summary of the Invention

[0005] The purpose of this application is to provide a method for determining the sideslip angle correction of the pitch moment coefficient of a propeller aircraft, which is used to calculate the change of pitch moment when the propeller aircraft lands in a strong crosswind and goes around.

[0006] The technical solution of this application is:

[0007] A method for determining the sideslip angle correction amount for the pitching moment coefficient of a propeller aircraft, comprising:

[0008] Step 1: Calculate the propeller parameter β0;

[0009] Step 2: Based on the propeller parameter β0, calculate the derivative C of the lateral force coefficient with respect to the sideslip angle, defined by the propeller speed and diameter. Yβ ';

[0010] Step 3: The derivative C of the lateral force coefficient with respect to the sideslip angle, defined based on propeller parameters β0, propeller speed, and diameter. Yβ 'Calculate the derivative of the pitching moment coefficient based on the incoming flow velocity pressure and the wing reference area.'

[0011] Step 4: Calculate the derivative of the pitching moment coefficient based on the incoming flow velocity pressure and the wing reference area. Calculate the sideslip angle correction ΔC for the pitch moment coefficient. m .

[0012] According to at least one embodiment of this application, in the above-described method for determining the sideslip angle correction of the pitching moment coefficient of a propeller-driven aircraft, step one, calculating the propeller parameter β0, specifically involves:

[0013]

[0014] in,

[0015] C' T The propeller thrust coefficient is defined based on engine thrust, propeller speed, and propeller disk diameter;

[0016] σ e This is the inherent effective factor of the blade;

[0017] J is the forward ratio of a propeller-driven aircraft;

[0018] B represents the number of blades.

[0019] According to at least one embodiment of this application, in the above-described method for determining the sideslip angle correction amount of the pitch moment coefficient of a propeller aircraft, in step one,

[0020] in,

[0021] p e For the pulling force of the engine;

[0022] ρ is the air density;

[0023] n is the propeller speed;

[0024] d is the diameter of the propeller disk.

[0025] According to at least one embodiment of this application, in the above-described method for determining the sideslip angle correction amount of the pitch moment coefficient of a propeller aircraft, in step one,

[0026] in,

[0027] V0 represents the incoming flow velocity.

[0028] According to at least one embodiment of this application, in the above-described method for determining the sideslip angle correction of the pitching moment coefficient of a propeller aircraft, in step one, σ e =0.0003B×AF;

[0029] in,

[0030] AF is the active factor for the blade.

[0031] According to at least one embodiment of this application, in the above-described method for determining the sideslip angle correction amount of the pitch moment coefficient of a propeller aircraft, in step one,

[0032] in,

[0033] c b Let be the chord length of the blade spanwise section at the station;

[0034] r represents the spanwise position of the blade section;

[0035] R is the radius of the propeller disk.

[0036] According to at least one embodiment of this application, in the above-described method for determining the sideslip angle correction of the pitching moment coefficient of a propeller-driven aircraft, in step two, based on the propeller parameter β0, the derivative C of the lateral force coefficient defined by the propeller speed and diameter with respect to the sideslip angle is calculated. Yβ For propellers rotating in the same direction, we have:

[0037]

[0038] According to at least one embodiment of this application, in the above-described method for determining the sideslip angle correction of the pitching moment coefficient of a propeller-driven aircraft, in step two, based on the propeller parameter β0, the derivative C of the lateral force coefficient defined by the propeller speed and diameter with respect to the sideslip angle is calculated. Yβ For counter-rotating propellers, we have:

[0039]

[0040] According to at least one embodiment of this application, in the above-described method for determining the sideslip angle correction of the pitching moment coefficient of a propeller-driven aircraft, in step three, the derivative C of the lateral force coefficient with respect to the sideslip angle, defined based on propeller parameters β0, propeller speed, and diameter, is... Yβ 'Calculate the derivative of the pitching moment coefficient based on the incoming flow velocity pressure and the wing reference area.' For propellers rotating in the same direction, we have:

[0041]

[0042] in,

[0043] Let C be the derivative of the pitching moment coefficient with respect to the sideslip angle, defined based on propeller speed and diameter, and the derivative of the lateral force coefficient with respect to the sideslip angle, defined based on propeller parameter β0 and propeller speed and diameter. Yβ 'calculate;

[0044] S p The area of ​​the propeller disk;

[0045] S ref This refers to the wing reference area.

[0046] C a The average aerodynamic chord length is given.

[0047] According to at least one embodiment of this application, in the above-described method for determining the sideslip angle correction amount of the pitch moment coefficient of a propeller aircraft, in step three,

[0048]

[0049] According to at least one embodiment of this application, in the above-described method for determining the sideslip angle correction of the pitching moment coefficient of a propeller-driven aircraft, in step three, the derivative C of the lateral force coefficient with respect to the sideslip angle, defined based on propeller parameters β0, propeller speed, and diameter, is... Yβ 'Calculate the derivative of the pitching moment coefficient based on the incoming flow velocity pressure and the wing reference area.' For propellers rotating in opposite directions:

[0050]

[0051] According to at least one embodiment of this application, in the above-described method for determining the sideslip angle correction of the pitching moment coefficient of a propeller-driven aircraft, in step four, the derivative of the pitching moment coefficient based on the incoming flow velocity pressure and the wing reference area is used. Calculate the sideslip angle correction ΔC for the pitch moment coefficient. m Specifically:

[0052]

[0053] N is the number of engines;

[0054] △C mβ0 The correction amount for the pitching moment coefficient generated by zero sideslip angle;

[0055] β e This is the effective sideslip angle of the propeller.

[0056] According to at least one embodiment of this application, in the above-described method for determining the sideslip angle correction of the pitching moment coefficient of a propeller aircraft, in step four, β e =β-ψ pb ;

[0057] in,

[0058] β is the fuselage sideslip angle;

[0059] ψ pb The lateral mounting angle of the tension line to the fuselage.

[0060] This application has at least the following beneficial technical effects:

[0061] This paper provides a method for determining the sideslip angle correction of the pitch moment coefficient of a propeller aircraft. It reflects the influence of sideslip angle, speed, engine thrust, number of engines, propeller diameter and speed, and blade efficiency on the pitch moment. It can accurately calculate the sideslip angle correction of the pitch moment coefficient, providing technical support for the calculation of pitch moment characteristics of propeller aircraft and supporting safe handling of propeller aircraft. Attached Figure Description

[0062] Figure 1 This is a schematic diagram of the method for determining the sideslip angle correction of the pitch moment coefficient of a propeller aircraft provided in the embodiments of this application.

[0063] To better illustrate this embodiment, some content in the accompanying drawings may be omitted. They are for illustrative purposes only and should not be construed as limiting the scope of this application. Detailed Implementation

[0064] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, and other related parts can be referred to the general design.

[0065] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms indicating direction used in this application description are used only to indicate relative direction or positional relationship; when the absolute position of the described object changes, its relative positional relationship may also change accordingly. The word "comprising" as used in this application description indicates that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, but does not exclude other elements or objects.

[0066] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, terms such as "installation" and "connection" used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0067] A method for determining the sideslip angle correction for the pitching moment coefficient of a propeller-driven aircraft, such as... Figure 1 As shown.

[0068] Step 1: Calculate the propeller parameter β0.

[0069]

[0070] in,

[0071] C' T The propeller thrust coefficient is defined based on engine thrust, propeller speed, and propeller disk diameter;

[0072] p eFor the pulling force of the engine;

[0073] ρ is the air density;

[0074] n is the propeller speed;

[0075] d is the diameter of the propeller disk.

[0076]

[0077] in,

[0078] J is the forward ratio of a propeller-driven aircraft;

[0079] V0 represents the incoming flow velocity.

[0080]

[0081] in,

[0082] σ e This is the inherent effective factor of the blade;

[0083] B represents the number of blades.

[0084] σ e =0.0003B×AF…………2-1

[0085] in,

[0086] AF is the active factor for the blade.

[0087]

[0088] in,

[0089] c b Let be the chord length of the blade spanwise section at the station;

[0090] r represents the spanwise position of the blade section;

[0091] R is the radius of the propeller disk.

[0092] When calculating the propeller parameter β0, the propeller thrust coefficient C', defined based on engine thrust, propeller speed, and propeller disk diameter, can be calculated first. T Then, the propeller parameter β0 is discretized between [0, 90] to construct the propeller parameter β0 array, and the value of the propeller parameter β0 is solved by interpolation algorithm.

[0093] Step 2: Based on the propeller parameter β0, calculate the derivative C of the lateral force coefficient with respect to the sideslip angle, defined by the propeller speed and diameter. Yβ '.

[0094] For propellers rotating in the same direction, we have:

[0095]

[0096]

[0097] in,

[0098] C Yβ The derivative of the lateral force is based on the incoming flow velocity pressure and the wing reference area;

[0099] S p The area of ​​the propeller disk;

[0100] S ref This is the reference area for the wing.

[0101] S p =πd 2 / 4…………3-3

[0102] For propellers rotating in opposite directions:

[0103]

[0104]

[0105] Step 3: The derivative C of the lateral force coefficient with respect to the sideslip angle, defined based on propeller parameters β0, propeller speed, and diameter. Yβ 'Calculate the derivative of the pitching moment coefficient based on the incoming flow velocity pressure and the wing reference area.'

[0106] For propellers rotating in the same direction, we have:

[0107]

[0108] in,

[0109] This is the derivative of the pitching moment coefficient with respect to the sideslip angle, defined based on propeller speed and diameter.

[0110]

[0111] in,

[0112] C a The average aerodynamic chord length is given.

[0113] For propellers rotating in opposite directions:

[0114]

[0115] Step 4: Calculate the derivative of the pitching moment coefficient based on the incoming flow velocity pressure and the wing reference area. Calculate the sideslip angle correction ΔC for the pitch moment coefficient. m .

[0116] β e =β-ψ pb …………7-1

[0117] in,

[0118] β e The effective sideslip angle of the propeller;

[0119] β is the fuselage sideslip angle;

[0120] ψ pb The lateral mounting angle of the tension line to the fuselage.

[0121]

[0122] in,

[0123] N is the number of engines;

[0124] ΔC mβ0 This is the correction amount for the pitching moment coefficient generated by zero sideslip angle.

[0125] In a specific example, the propeller-driven aircraft has a wing area of ​​65 m², a mean aerodynamic chord length of 2.5 m, and two co-rotating turboprop engines mounted under the wing. The propeller disk diameter is 4.4 m, the number of blades is 6, the blade parameter AF is 188, and the lateral mounting angle of the engine thrust axis relative to the fuselage axis is 0°. The incoming flow velocity is 75 m / s, the engine speed is 23.6 rpm, the corresponding engine thrust is 33.56 kN, and the pitching moment coefficient at zero sideslip angle is 0.006. Using the method for determining the sideslip angle correction of the pitching moment coefficient of a propeller-driven aircraft disclosed in the above example, the correction amount of the pitching moment coefficient for a 10° sideslip angle is calculated as follows:

[0126] 1. Calculate β0, as shown in the table below:

[0127] parameter value Label <![CDATA[p e ]]> 33.56KN enter ρ 1.225 enter n 23.6 rpm enter d 4.4m enter <![CDATA[C T ]]> 0.131 Formula 1-1 <![CDATA[V0]]> 75m / s enter J 0.722 Formula 1-2 B 6 enter AF 188 enter σ 0.338 Equation 2-1 <![CDATA[β0]]> 23.25° Formula 1-3

[0128] II. Calculate C Yβ 'and C Yβ As shown in the table below:

[0129]

[0130]

[0131] III. Calculation as well as As shown in the table below:

[0132]

[0133] IV. Calculate △Cm As shown in the table below:

[0134]

[0135]

[0136] The technical solution of this application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A method for determining the sideslip angle correction amount for the pitching moment coefficient of a propeller-driven aircraft, characterized in that, include: Step 1: Calculate the propeller parameter β0; Step 2: Based on the propeller parameter β0, calculate the derivative C of the lateral force coefficient with respect to the sideslip angle, defined by the propeller speed and diameter. Yβ '; Step 3: The derivative C of the lateral force coefficient with respect to the sideslip angle, defined based on propeller parameters β0, propeller speed, and diameter. Yβ 'Calculate the derivative of the pitching moment coefficient based on the incoming flow velocity pressure and the wing reference area.' Step 4: Calculate the derivative of the pitching moment coefficient based on the incoming flow velocity pressure and the wing reference area. Calculate the sideslip angle correction ΔC for the pitch moment coefficient. m ; In step one, the propeller parameter β0 is calculated as follows: in, C' T The propeller thrust coefficient is defined based on engine thrust, propeller speed, and propeller disk diameter; σ e This is the inherent effective factor of the blade; J is the forward ratio of a propeller-driven aircraft; B represents the number of blades; In step two, based on the propeller parameter β0, the derivative C of the lateral force coefficient with respect to the sideslip angle, defined by the propeller speed and diameter, is calculated. Yβ For propellers rotating in the same direction, we have: In step three, the derivative C of the lateral force coefficient with respect to the sideslip angle, defined based on the propeller parameter β0, propeller speed, and diameter, is calculated. Yβ 'Calculate the derivative of the pitching moment coefficient based on the incoming flow velocity pressure and the wing reference area.' For propellers rotating in the same direction, we have: in, Let C be the derivative of the pitching moment coefficient with respect to the sideslip angle, defined based on propeller speed and diameter, and the derivative of the lateral force coefficient with respect to the sideslip angle, defined based on propeller parameter β0 and propeller speed and diameter. Yβ 'calculate; S p The area of ​​the propeller disk; S ref This refers to the wing reference area. C a The average aerodynamic chord length; In step four, the derivative of the pitching moment coefficient based on the incoming flow velocity pressure and the wing reference area is used. Calculate the sideslip angle correction ΔC for the pitch moment coefficient. m Specifically: N is the number of engines; ΔC mβ0 The correction amount for the pitching moment coefficient generated by zero sideslip angle; β e This is the effective sideslip angle of the propeller.

2. The method for determining the sideslip angle correction amount of the pitch moment coefficient of a propeller-driven aircraft according to claim 1, characterized in that, In step one, in, p e For the pulling force of the engine; ρ is the air density; n is the propeller speed; d is the diameter of the propeller disk.

3. The method for determining the sideslip angle correction amount of the pitching moment coefficient of a propeller-driven aircraft according to claim 2, characterized in that, In step one, in, V0 represents the incoming flow velocity.

4. The method for determining the sideslip angle correction amount of the pitching moment coefficient of a propeller-driven aircraft according to claim 3, characterized in that, In step one, σ e =0.0003B×AF; in, AF is the active factor for the blade.

5. The method for determining the sideslip angle correction amount of the pitching moment coefficient of a propeller-driven aircraft according to claim 4, characterized in that, In step one, in, c b Let be the chord length of the blade spanwise section at the station; r represents the spanwise position of the blade section; R is the radius of the propeller disk.

6. The method for determining the sideslip angle correction amount for the pitching moment coefficient of a propeller-driven aircraft according to claim 5, characterized in that, In step two, based on the propeller parameter β0, the derivative C of the lateral force coefficient with respect to the sideslip angle, defined by the propeller speed and diameter, is calculated. Yβ For counter-rotating propellers, we have:

7. The method for determining the sideslip angle correction amount of the pitch moment coefficient of a propeller-driven aircraft according to claim 6, characterized in that, In step three, 8. The method for determining the sideslip angle correction amount of the pitch moment coefficient of a propeller aircraft according to claim 7, characterized in that, In step three, the derivative C of the lateral force coefficient with respect to the sideslip angle, defined based on the propeller parameter β0, propeller speed, and diameter, is calculated. Yβ 'Calculate the derivative of the pitching moment coefficient based on the incoming flow velocity pressure and the wing reference area.' For propellers rotating in opposite directions:

9. The method for determining the sideslip angle correction amount of the pitch moment coefficient of a propeller-driven aircraft according to claim 8, characterized in that, In step four, β e =β-ψ pb ; in, β is the fuselage sideslip angle; ψ pb The lateral mounting angle of the tension line to the fuselage.

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