Method for determining slipstream pressure center of propeller-driven aircraft

Abstract

The invention belongs to the technical field of propeller-driven aircraft control, and particularly relates to a propeller-driven aircraft slip flow pressure center determination method which comprises the following steps: step 1, calculating a propeller parameter beta0; step 2, calculating a normal force derivative CN alpha e of the propeller disc; 3, calculating a ratio # imgabs0 # of an included angle between a slip flow velocity vector and a thrust center line to an attack angle of airflow relative to a tension line, and calculating a ratio # imgabs1 # of a deflection angle of slip flow relative to a tension axis to a flight sideslip angle change; 4, calculating a parameter alpha z corresponding to the attack angle; 5, a flap parameter phi is calculated; step 6, calculating a ratio # imgabs2 of a lift coefficient of a wing attack angle corresponding parameter alpha z based on the thin wing theory to a lift coefficient of a wing flap deflection delta attack angle corresponding parameter alpha z based on the thin wing theory; step 7, calculating a wing flap related parameter # imgabs3; step 8, calculating a wing chord direction position of a propeller slip flow pressure center; and 9, calculating the position ys in the wing chord direction of the slipstream pressure center of the propeller.

Description

Technical Field

[0001] The present application belongs to the technical field of propeller aircraft control, and in particular relates to a method for determining the slipstream pressure center of a propeller aircraft. Background Art

[0002] Slipstream can effectively increase the lift of propeller aircraft in take-off and landing configurations, but large pull coefficients will significantly reduce the longitudinal and lateral static stability of the aircraft. The important reason for this is that the slipstream changes the position of the wing's center of pressure.

[0003] In order to correctly evaluate the longitudinal static stability and lateral static stability of propeller aircraft under large thrust coefficients, it is necessary to accurately determine the position of the slipstream pressure center. For this, there is currently a lack of efficient and simple technical means. In view of this, this application is proposed. Summary of the invention

[0004] The purpose of the present application is to provide a method for determining the slipstream pressure center of a propeller aircraft to overcome or alleviate at least one aspect of the technical deficiencies of the known technologies.

[0005] The technical solution of this application is:

[0006] A method for determining the slipstream pressure center of a propeller aircraft, comprising:

[0007] Step 1: Calculate propeller parameter β0;

[0008] Step 2: Calculate the normal force derivative C of the propeller disk based on the propeller parameter β0 Nαe ;

[0009] Step 3: Based on the normal force derivative C of the propeller disk Nαe , calculate the ratio of the angle between the slipstream velocity vector and the thrust centerline to the angle of attack of the airflow relative to the thrust line And calculate the ratio of the slipstream deflection angle relative to the pull axis to the change in the flight sideslip angle

[0010] Step 4: Based on the ratio of the angle between the slipstream velocity vector and the thrust centerline to the angle of attack of the airflow relative to the pull line Calculate the angle of attack corresponding parameter α z ;

[0011] Step 5: Calculate flap parameter φ;

[0012] Step 6: Based on the flap parameter φ, calculate the corresponding parameter α of the wing angle of attack based on the thin wing theory z The lift coefficient and the corresponding parameter α of the flap deflection δ angle of attack based on the thin wing theory z The ratio of the lift coefficient

[0013] Step 7: Calculate flap-related parameters using flap parameter φ

[0014] Step 8: Based on flap related parameters Corresponding parameter α of wing angle of attack based on thin wing theory z The lift coefficient and the corresponding parameter α of the flap deflection δ angle of attack based on the thin wing theory z The ratio of the lift coefficient Calculate the chord-wise position x of the propeller slipstream pressure center s , that is, the axial distance from the propeller slipstream pressure center to the local wing leading edge point;

[0015] Step 9: Based on the chord-wise position x of the propeller slipstream pressure center s , the ratio of the slipstream deflection angle relative to the pull axis to the change in the flight sideslip angle Calculate the chord-wise position y of the propeller slipstream pressure center s , which is the spanwise distance from the propeller slipstream pressure center to the fuselage centerline.

[0016] According to at least one embodiment of the present application, in the above-mentioned method for determining the slipstream pressure center of a propeller aircraft, step 1 is specifically as follows:

[0017]

[0018] in,

[0019] C' T is the propeller thrust coefficient defined based on the propeller speed and the propeller disk diameter;

[0020] σ e is the intrinsic effective factor of the blade;

[0021] B is the number of blades;

[0022] J is the advance ratio of the propeller aircraft.

[0023] According to at least one embodiment of the present application, in the above-mentioned method for determining the slipstream pressure center of a propeller aircraft, step 1 includes:

[0024]

[0025] in,

[0026] p e is the pulling force of the engine;

[0027] ρ is the air density;

[0028] n is the propeller speed;

[0029] D is the propeller disc diameter.

[0030] According to at least one embodiment of the present application, in the above-mentioned method for determining the slipstream pressure center of a propeller aircraft, step 1 includes:

[0031] σ e = = 0.0003B × AF;

[0032] in,

[0033] AF is the active factor of the blade.

[0034] According to at least one embodiment of the present application, in the above-mentioned method for determining the slipstream pressure center of a propeller aircraft, step 1 includes:

[0035]

[0036] in,

[0037] V0 is the incoming flow velocity.

[0038] According to at least one embodiment of the present application, in the above-mentioned method for determining the slipstream pressure center of a propeller aircraft, step 2 is specifically as follows:

[0039]

[0040] According to at least one embodiment of the present application, in the above-mentioned method for determining the slipstream pressure center of a propeller aircraft, step three is specifically as follows:

[0041]

[0042] in,

[0043] C T is the thrust coefficient of the engine defined based on the slipstream pressure and the propeller disk area;

[0044] is the lateral force derivative of the propeller disc;

[0045] S ref is the wing reference area;

[0046] S p is the paddle disc area;

[0047] is the ratio of the incoming flow velocity to the slipstream velocity;

[0048]

[0049] According to at least one embodiment of the present application, in the above-mentioned method for determining the slipstream pressure center of a propeller aircraft, step three includes:

[0050] S p =πD 2 / 4;

[0051]

[0052] in,

[0053] T C The aircraft drag coefficient is defined based on the aircraft drag, incoming flow pressure and wing reference area.

[0054] According to at least one embodiment of the present application, in the above-mentioned method for determining the slipstream pressure center of a propeller aircraft, step three includes:

[0055]

[0056] in,

[0057] q s is the slip velocity pressure;

[0058] or,

[0059]

[0060] in,

[0061] T C The aircraft drag coefficient is defined based on the aircraft drag, incoming flow pressure and wing reference area;

[0062] N is the number of engines;

[0063]

[0064] in,

[0065] q0 is the incoming flow velocity pressure;

[0066]

[0067] According to at least one embodiment of the present application, in the above-mentioned method for determining the slipstream pressure center of a propeller aircraft, step 4 is specifically as follows:

[0068] i w =θ wi +θ pb ;

[0069] in,

[0070] i w is the angle of attack of the engine pull line relative to the local wing chord line;

[0071] θ wi is the installation angle of the local wing;

[0072] θ pb is the angle of attack of the engine pulling force line relative to the fuselage centerline;

[0073] α w =α+θ wi ;

[0074] α w is the wing angle of attack;

[0075] α is the fuselage angle of attack;

[0076] θ wi Installing corners for local wings;

[0077]

[0078] in,

[0079] α p is the angle of attack of the incoming flow relative to the tension line;

[0080] α0 is the zero lift angle of attack when the aircraft flaps are fully retracted and the power is off;

[0081] α s is the angle between the slipstream velocity vector and the thrust centerline;

[0082] α p is the angle of attack of the airflow relative to the line of force.

[0083] According to at least one embodiment of the present application, in the above-mentioned method for determining the slipstream pressure center of a propeller aircraft, step five is specifically as follows:

[0084]

[0085] in,

[0086] dtbf is the intermediate calculation parameter;

[0087] δ t1 , δ t2 The double-slotted Fuller-type flap deflection angle of the rear wing;

[0088] f=interp1(dtbfsz,fsz,dtbf);

[0089] in,

[0090] f is the intermediate calculation parameter;

[0091] interp1 is a linear interpolation function;

[0092] dtbfsz and fsz are interpolation calculation arrays;

[0093] C t =fC t1 +(1-f)C t2 ;

[0094] in,

[0095] C t is the effective chord length of the two flaps of the double-slotted flap;

[0096] C t1 , C t2 is the chord length of the two flaps of the double-slotted flap;

[0097]

[0098] in,

[0099] E is the relative chord length of the engine installation position;

[0100] C is the chord length of the wing at the engine installation position;

[0101] C' is the chord length of the wing with the flaps extended;

[0102] φ=an cos(2E-1);

[0103] in,

[0104] an cos is the inverse cosine function.

[0105] According to at least one embodiment of the present application, in the above-mentioned method for determining the slipstream pressure center of a propeller aircraft, step six is ​​specifically as follows:

[0106]

[0107] According to at least one embodiment of the present application, in the above-mentioned method for determining the slipstream pressure center of a propeller aircraft, step seven is specifically as follows:

[0108]

[0109] According to at least one embodiment of the present application, in the above-mentioned method for determining the slipstream pressure center of a propeller aircraft, step eight is specifically as follows:

[0110]

[0111] According to at least one embodiment of the present application, in the above-mentioned method for determining the slipstream pressure center of a propeller aircraft, step nine is specifically as follows:

[0112]

[0113] in,

[0114] β s is the deflection angle of the slipstream relative to the tension axis;

[0115] β is the flight sideslip angle; ys =y p -(x le +x s )β s ;

[0117] in,

[0118] y p is the spanwise distance between the engine pulling axis and the fuselage centerline;

[0119] x le It is the axial distance behind the propeller disc of the wing leading edge at the engine installation position.

[0120] This application has at least the following beneficial technical effects:

[0121] Provided is a method for determining the slipstream pressure center of a propeller aircraft, which fully considers the influence of angle of attack, speed, engine thrust, number of engines, size and position of engine nacelle, angle of attack of thrust line, wing mounting angle, propeller diameter, flap deflection angle, flap chord length, normal force derivative and lateral force derivative of propeller disc on the position of the slipstream pressure center, calculates the position of the slipstream pressure center, has high accuracy, is efficient and simple, and can provide support for the correct evaluation of longitudinal static stability and lateral static stability of propeller aircraft under large thrust coefficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0122] Figure 1 It is a schematic diagram of a method for determining the slipstream pressure center of a propeller aircraft provided in an embodiment of the present application.

[0123] In order to better illustrate the present embodiment, some contents of the drawings may be omitted, which is only used for illustrative purposes and should not be construed as limiting the present application. DETAILED DESCRIPTION

[0124] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be described in further detail in detail and in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design.

[0125] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application shall have the usual meanings understood by those of ordinary skill in the art to which this application belongs. The words used in the description of this application to indicate orientation are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. The word "include" used in the description of this application indicates that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0126] In addition, it should be noted that, unless otherwise clearly specified and limited, the words "installation", "connection" and similar terms used in the description of this application should be understood in a broad sense. For example, the 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. Technical personnel in the field can understand its specific meaning in this application according to the specific circumstances.

[0127] The purpose of the present invention is to provide a calculation model for the position of the slipstream pressure center of a propeller powered aircraft, which is used for calculating the longitudinal static stability and the lateral static stability of the propeller powered aircraft.

[0128] Angle of attack, speed, engine thrust, engine size and mounting position, propeller disk diameter, propeller disk normal force derivative, and flap configuration will have a significant impact on the position of the slipstream pressure center.

[0129] The technical solution of the present invention is: firstly, the sensitive factors affecting the position of the slipstream pressure center of the propeller aircraft are theoretically analyzed, and then a calculation model of the propeller slipstream pressure center position is constructed based on the theoretical analysis and test data. The specific contents are as follows:

[0130] Theoretical analysis shows that the angle of attack, speed, engine thrust, engine size and installation position, propeller disk diameter, propeller disk normal force derivative, flap configuration, etc. will have a significant impact on the position of the slipstream pressure center. Based on this, the present application provides a method for determining the slipstream pressure center of a propeller aircraft, such as Figure 1 shown.

[0131] Step 1: Calculate propeller parameter β0.

[0132]

[0133] in,

[0134] C' T is the propeller thrust coefficient defined based on the propeller speed and the propeller disk diameter;

[0135] p e is the pulling force of the engine;

[0136] ρ is the air density;

[0137] n is the propeller speed;

[0138] D is the propeller disc diameter.

[0139]

[0140] in,

[0141] J is the advance ratio of the propeller aircraft;

[0142] V0 is the incoming flow velocity.

[0143] σ e = = 0.0003B × AF ………… 1-3

[0144] in,

[0145] σ e is the intrinsic effective factor of the blade;

[0146] B is the number of blades;

[0147] AF is the active factor of the blade.

[0148]

[0149] When solving the propeller parameter β0, the propeller thrust coefficient C' defined based on the propeller speed and the propeller disk diameter can be calculated first. T , then discretize the parameter β0 between [0,90], construct the β0 array, and use the interpolation algorithm to solve the numerical solution of β0.

[0150] Step 2: Calculate the normal force derivative C of the propeller disk based on the propeller parameter β0 Nαe .

[0151]

[0152] Step 3: Based on the normal force derivative C of the propeller disk Nαe , calculate the ratio of the angle between the slipstream velocity vector and the thrust centerline to the angle of attack of the airflow relative to the thrust line And calculate the ratio of the deflection angle of the slipstream relative to the axis of pull to the change in the flight sideslip angle

[0153] S p =πD 2 / 4…………3-1

[0154] in,

[0155] S p is the paddle disc area.

[0156]

[0157] in,

[0158] is the lateral force derivative of the propeller disc;

[0159] S ref is the reference area of ​​the wing.

[0160]

[0161] in,

[0162] q0 is the incoming flow rate pressure.

[0163]

[0164] in,

[0165] T C The aircraft drag coefficient is defined based on the aircraft drag, incoming flow pressure and wing reference area.

[0166] or,

[0167] in,

[0168] C T is the thrust coefficient of the engine defined based on the slipstream pressure and the propeller disk area;

[0169] q s is the slip velocity pressure;

[0170] N is the number of engines.

[0171]

[0172] in,

[0173] is the ratio of the incoming flow velocity to the slipstream velocity.

[0174]

[0175] Step 4: Based on the ratio of the angle between the slipstream velocity vector and the thrust centerline to the angle of attack of the airflow relative to the pull line Calculate the angle of attack corresponding parameter α z .

[0176] i w =θ wi +θ pb …………4-1

[0177] in,

[0178] iw is the angle of attack of the engine pull line relative to the local wing chord line;

[0179] θ wi is the installation angle of the local wing;

[0180] θ pb It is the angle of attack of the engine tension line relative to the center axis of the fuselage.

[0181] α w =α+θ wi …………4-2

[0182] α w is the wing angle of attack;

[0183] α is the fuselage angle of attack;

[0184] θ wi Install corners for local wings.

[0185]

[0186] in,

[0187] α p is the angle of attack of the incoming flow relative to the tension line;

[0188] α0 is the zero lift angle of attack when the aircraft flaps are fully retracted and the power is off;

[0189] α s is the angle between the slipstream velocity vector and the thrust centerline;

[0190] α p is the angle of attack of the airflow relative to the line of force.

[0191] Step 5: Calculate flap parameter φ.

[0192]

[0193] in,

[0194] dtbf is the intermediate calculation parameter;

[0195] δ t1 , δ t2 The deflection angle of the double-slotted Fuller flap on the rear wing.

[0196] f=interp1(dtbfsz,fsz,dtbf)…………5-2

[0197] in,

[0198] f is the intermediate calculation parameter;

[0199] interp1 is a linear interpolation function;

[0200] dtbfsz and fsz are interpolation calculation arrays, which can be referred to as follows: dtbfsz 0 0.2 0.4 0.6 0.8 1 plant 0 0.16 0.34 0.55 0.76 1

[0201] C t =fC t1 +(1-f)C t2 …………5-3

[0202] in,

[0203] C t is the effective chord length of the two flaps of the double-slotted flap;

[0204] C t1 , C t2 is the chord length of the two flaps of the double-slotted flap.

[0205]

[0206] in,

[0207] E is the relative chord length of the engine installation position;

[0208] C is the chord length of the wing at the engine installation position;

[0209] C' is the chord length of the wing with the flaps extended.

[0210] φ=an cos(2E-1)…………5-5

[0211] in,

[0212] an cos is the inverse cosine function.

[0213] Step 6: Based on the flap parameter φ, calculate the corresponding parameter α of the wing angle of attack based on the thin wing theory z The lift coefficient and the corresponding parameter α of the flap deflection δ angle of attack based on the thin wing theory z The ratio of the lift coefficient

[0214]

[0215] in,

[0216] C Lth (α z ,0) is the parameter α corresponding to the wing angle of attack based on the thin wing theory z The lift coefficient of

[0217] C Lth (α z ,δ) is the parameter α corresponding to the flap deflection δ angle of attack based on the thin wing theory z The lift coefficient.

[0218] Step 7: Calculate flap-related parameters using flap parameter φ

[0219]

[0220] Step 8: Based on flap related parameters Corresponding parameter α of wing angle of attack based on thin wing theory z The lift coefficient and the corresponding parameter α of the flap deflection δ angle of attack based on the thin wing theory z The ratio of the lift coefficient Calculate the chord-wise position x of the propeller slipstream pressure center s , that is, the axial distance from the propeller slipstream pressure center to the local wing leading edge point.

[0221]

[0222] Step 9: Based on the chord-wise position x of the propeller slipstream pressure center s , the ratio of the slipstream deflection angle relative to the pull axis to the change in the flight sideslip angle Calculate the chord-wise position y of the propeller slipstream pressure center s , which is the spanwise distance from the propeller slipstream pressure center to the fuselage centerline.

[0223]

[0224] in,

[0225] β s is the deflection angle of the slipstream relative to the tension axis;

[0226] β is the flight sideslip angle. y s =y p -(x le +x s )β s

[0227] …………9-2

[0228] in,

[0229] y p is the spanwise distance between the engine pulling axis and the fuselage centerline;

[0230] x le It is the axial distance behind the propeller disc of the wing leading edge at the engine installation position.

[0231] In a specific example, the aircraft has a wing area of ​​65m2, a wingspan of 26.2m, an aspect ratio of 10.56, and an average aerodynamic chord length of 2.5m. Two turboprop engines are suspended under the wing, with a propeller disk diameter of 4.4m, 6 blades, and a blade parameter AF of 188. The local wing chord length is 2.6m, the thrust axis has an angle of attack of 1° relative to the fuselage axis, and the local wing installation angle is 3°. Takeoff configuration: the trailing edge double-slotted Fuller flap has a deflection angle of 20°+8°, the relative chord length of the two flaps is 0.2+0.1, and the chord length of the wing after the flaps are released is 1.2 times the original chord length. The chord-wise distance from the leading edge of the wing to the propeller disk at the engine installation position is 1.36m, and the span-wise distance from the engine thrust axis to the fuselage centerline is 5.1m. The zero lift angle of attack of the aircraft with flaps retracted in the unpowered state is -2°.

[0232] According to the method for determining the slipstream pressure center of a propeller aircraft disclosed in the above embodiment, the flow velocity is calculated to be 75 m / s, the engine speed is 23.6 rpm, the corresponding engine thrust is 33.56 KN, the aircraft angle of attack is 13.5°, and the sideslip angle is 10°. The specific reference is as follows:

[0233] 1) Calculate β0 as shown in the following table:

[0234] 2) Calculate C Nαe , as shown in the following table:

[0235] 3) Calculation As shown in the following table:

[0236] 4) Calculate α z , as shown in the following table:

[0237] 5) Calculate φ as shown in the following table:

[0238] 6) Calculation As shown in the following table:

[0239] 7) Calculation As shown in the following table:

[0240] 8) Calculate x s , as shown in the following table:

[0241] 9) Calculate y s , as shown in the following table:

[0242] So far, the technical solution of the present 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 the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present 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 fall within the scope of protection of the present application.

Claims

1. A method for determining the slipstream pressure center of a propeller aircraft, characterized in that: include: Step 1: Calculate propeller parameter β0; Step 2: Calculate the normal force derivative C of the propeller disk based on the propeller parameter β0 Nαe ; Step 3: Based on the normal force derivative C of the propeller disk Nαe , calculate the ratio of the angle between the slipstream velocity vector and the thrust centerline to the angle of attack of the airflow relative to the thrust line And calculate the ratio of the slipstream deflection angle relative to the pull axis to the change in the flight sideslip angle Step 4: Based on the ratio of the angle between the slipstream velocity vector and the thrust centerline to the angle of attack of the airflow relative to the pull line Calculate the angle of attack corresponding parameter α z ; Step 5: Calculate flap parameter φ; Step 6: Based on the flap parameter φ, calculate the corresponding parameter α of the wing angle of attack based on the thin wing theory z The lift coefficient and the corresponding parameter α of the flap deflection δ angle of attack based on the thin wing theory z The ratio of the lift coefficient Step 7: Calculate flap-related parameters using flap parameter φ Step 8: Based on flap related parameters Parameter α corresponding to the wing angle of attack based on thin wing theory z The lift coefficient and the corresponding parameter α of the flap deflection δ angle of attack based on the thin wing theory z The ratio of the lift coefficient Calculate the chord-wise position x of the propeller slipstream pressure center s ; Step 9: Based on the chord-wise position x of the propeller slipstream pressure center s , the ratio of the slipstream deflection angle relative to the pull axis to the change in the flight sideslip angle Calculate the chord-wise position y of the propeller slipstream pressure center s .

2. The method for determining the slipstream pressure center of a propeller aircraft according to claim 1, characterized in that: Step 1 is as follows: in, C' T is the propeller thrust coefficient defined based on the propeller speed and the propeller disk diameter; σ e is the intrinsic effective factor of the blade; B is the number of blades; J is the advance ratio of the propeller aircraft.

3. The method for determining the slipstream pressure center of a propeller aircraft according to claim 2, characterized in that: In step one, there are: in, p e is the pulling force of the engine; ρ is the air density; n is the propeller speed; D is the propeller disc diameter.

4. The method for determining the slipstream pressure center of a propeller aircraft according to claim 3, characterized in that: In step one, there are: s e ==0.0003B×AF; in, AF is the active factor of the blade.

5. The method for determining the slipstream pressure center of a propeller aircraft according to claim 4, characterized in that: In step one, there are: in, V0 is the incoming flow velocity.

6. The method for determining the slipstream pressure center of a propeller aircraft according to claim 5, characterized in that: Step 2 is as follows:

7. The method for determining the slipstream pressure center of a propeller aircraft according to claim 6, characterized in that: Step three is as follows: in, C T is the thrust coefficient of the engine defined based on the slipstream pressure and the propeller disk area; is the lateral force derivative of the propeller disc; S ref is the wing reference area; S p is the paddle disc area; is the ratio of the incoming flow velocity to the slipstream velocity; 8. The method for determining the slipstream pressure center of a propeller aircraft according to claim 7, characterized in that: In step three, there are: S p =πD 2 / 4; in, T C The aircraft drag coefficient is defined based on the aircraft drag, incoming flow pressure and wing reference area.

9. The method for determining the slipstream pressure center of a propeller aircraft according to claim 8, characterized in that: In step three, there are: in, q s is the slip velocity pressure; or, in, T C The aircraft drag coefficient is defined based on the aircraft drag, incoming flow pressure and wing reference area; N is the number of engines; in, q0 is the incoming flow velocity pressure; q0=0.5ρV0 2 。 10. The method for determining the slipstream pressure center of a propeller aircraft according to claim 9, characterized in that: Step 4 is as follows: I w =θ wi +θ pb ; in, i w is the angle of attack of the engine pull line relative to the local wing chord line; θ wi is the installation angle of the local wing; θ pb is the angle of attack of the engine pulling force line relative to the fuselage centerline; a w =α+θ wi ; α w is the wing angle of attack; α is the fuselage angle of attack; θ wi Installing corners for local wings; in, α p is the angle of attack of the incoming flow relative to the tension line; α0 is the zero lift angle of attack when the aircraft flaps are fully retracted and the power is off; α s is the angle between the slipstream velocity vector and the thrust centerline; α p is the angle of attack of the airflow relative to the line of force.

11. The method for determining the slipstream pressure center of a propeller aircraft according to claim 10, characterized in that: Step 5 is as follows: in, dtbf is the intermediate calculation parameter; δ t1 , δ t2 The double-slotted Fuller-type flap deflection angle of the rear wing; f=interp1(dtbfsz,fsz,dtbf); in, f is the intermediate calculation parameter; interp1 is a linear interpolation function; dtbfsz and fsz are interpolation calculation arrays; C t =fC t1 +(1-f)C t2 ; in, C t is the effective chord length of the two flaps of the double-slotted flap; C t1 , C t2 is the chord length of the two flaps of the double-slotted flap; in, E is the relative chord length of the engine installation position; C is the chord length of the wing at the engine installation position; C' is the chord length of the wing with the flaps extended; φ=an cos(2E-1); in, an cos is the inverse cosine function.

12. The method for determining the slipstream pressure center of a propeller aircraft according to claim 10, characterized in that: Step 6 is as follows:

13. The method for determining the slipstream pressure center of a propeller aircraft according to claim 12, characterized in that: Step 7 is as follows:

14. The method for determining the slipstream pressure center of a propeller aircraft according to claim 13, characterized in that: Step 8 is as follows:

15. The method for determining the slipstream pressure center of a propeller aircraft according to claim 14, characterized in that: Step nine is as follows: in, β s is the deflection angle of the slipstream relative to the tension axis; β is the flight sideslip angle; and s =and p -(x le +x s )β s ; in, y p is the spanwise distance between the engine pulling axis and the fuselage centerline; x le It is the axial distance behind the propeller disc of the wing leading edge at the engine installation position.

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