Short-distance takeoff method and system suitable for tilt-rotor aircraft

Abstract

The invention belongs to the technical field of flight control, and relates to a short-distance take-off method and system suitable for a tilt-rotor aircraft. The method comprises the following steps: S1, receiving a short-distance takeoff signal of the tilt-rotor aircraft; and S2, the front engine located at the nose is controlled to deflect, the front propeller is driven to deflect downwards till a set acute angle is formed between the tension shaft of the front propeller and the plane of the fuselage, and meanwhile the rear engine located at the tail is controlled to keep the tension shaft of the rear propeller perpendicular to the plane of the fuselage all the time. According to the invention, by adjusting the position of the engine, the aerodynamic interference of the rotor wing to the wing in the short-distance takeoff process of the tilt-rotor aircraft is reduced, the longitudinal control torque in the short-distance takeoff process of the tilt-rotor aircraft is increased, and the short-distance takeoff efficiency of the aircraft is improved.

Description

Technical Field

[0001] The present application belongs to the field of flight control technology, and in particular relates to a short-distance takeoff method and system suitable for a tilt-rotor aircraft. Background Art

[0002] As a high-speed, long-distance means of transportation, airplanes play an irreplaceable role in modern military and civilian fields. According to the flight mode of the aircraft, aircraft can usually be divided into fixed-wing aircraft and rotary-wing aircraft. Fixed-wing aircraft refers to aircraft whose wings are relatively fixed to the fuselage, such as the Boeing 737 and F-15. Rotary-wing aircraft refers to aircraft whose wing surfaces that generate lift rotate relative to the fuselage, such as the "Black Hawk" and "Apache".

[0003] Fixed-wing aircraft and rotary-wing aircraft have their own characteristics in terms of usage and mission capabilities. Fixed-wing aircraft require a longer runway for takeoff and landing, have a fast flying speed in the air, have a strong loading capacity, and have a long range. Rotary-wing aircraft only need a flat ground for takeoff and landing, have a relatively slow flying speed in the air, have a relatively weak loading capacity, and have a relatively short range.

[0004] Engineers and designers tried to combine the advantages of fixed-wing aircraft and rotary-wing aircraft until the CV-22 Osprey aircraft appeared, and finally equipped the military with this aircraft that can take off and land vertically and has strong mission capabilities on a large scale. After entering service, the Osprey aircraft showed high battlefield adaptability and combat value, and received high praise from the US Marine Corps.

[0005] The Osprey has a vertical takeoff mode and a short takeoff mode. In the vertical takeoff mode, the Osprey takes off directly through the pull of the rotor like a helicopter. In the short takeoff mode, the Osprey tilts the engine compartment slightly forward, pulls the aircraft forward, increases the speed of the aircraft, and generates a certain amount of pull from the wings, which then takes off in combination with the pull of the engine in the vertical direction.

[0006] In theory, short-distance takeoffs have certain performance advantages over vertical takeoffs. Because the wings generate lift, the takeoff weight of an aircraft for short-distance takeoffs is greater than that for vertical takeoffs. However, the Osprey's short-distance takeoff advantage is not obvious.

[0007] The first is the aerodynamic interference between the rotor and wing of the Osprey aircraft. The engine compartment of the Osprey aircraft is located at the wing tip. During short-distance takeoff, two huge propellers cover the front and upper part of the wing. The aerodynamic forces on the rotor and the fixed wing interfere with each other, increasing the difficulty of the aircraft's aerodynamic design and flight mechanics processing, and the lift generated by the aircraft's wing is very limited.

[0008] Secondly, the Osprey aircraft is very difficult to control during short-distance takeoff. The thrust of the engine propeller of the Osprey aircraft is huge during short-distance takeoff, and the thrust axis passes through the center of gravity of the aircraft. Therefore, the impact of the engine propeller of the Osprey aircraft on the longitudinal operation of the aircraft is relatively small. The aerodynamic force of the aircraft's aerodynamic operating surface during short-distance takeoff and landing is very small, and the longitudinal operation capability is limited. In summary, the Osprey aircraft is very difficult to control during short-distance takeoff. Summary of the invention

[0009] In order to solve the above problems, the present application provides a short-distance takeoff method and system applicable to a tilt-rotor aircraft, so as to reduce the aerodynamic interference between the rotor and wing of the aircraft, increase the longitudinal control capability, and reduce the control difficulty during the short-distance takeoff process.

[0010] The first aspect of the present application provides a short takeoff method applicable to a tilt-rotor aircraft, which mainly includes:

[0011] Step S1, receiving a short take-off signal of a tilt-rotor aircraft;

[0012] Step S2, controlling the front engine located at the nose to deflect, driving the front propeller to deflect downward until the thrust axis of the front propeller forms a set acute angle with the horizontal plane of the fuselage, and at the same time controlling the rear engine located at the tail to keep the thrust axis of the rear propeller always perpendicular to the horizontal plane of the fuselage.

[0013] Preferably, step S2 further comprises:

[0014] Control the output power of the front engine and the rear engine so that the power of the front propeller is greater than that of the rear propeller.

[0015] Preferably, the front engine is connected to the power distribution device via a front interactive transmission shaft, and the rear engine is connected to the power distribution device via a rear interactive transmission shaft, and power is redistributed to the front propeller and the rear propeller via the power distribution device.

[0016] Preferably, the positions of the front engine and the rear engine on the aircraft are configured so that, when the aircraft performs short takeoff and landing, the distance from the center of gravity of the aircraft to the thrust axis of the front propeller is smaller than the distance from the center of gravity of the aircraft to the thrust axis of the rear propeller.

[0017] The second aspect of the present application provides a short take-off system suitable for a tilt-rotor aircraft, mainly comprising:

[0018] A short take-off signal receiving module is used to receive a short take-off signal of a tilt-rotor aircraft;

[0019] The deflection control module is used to control the deflection of the front engine located at the nose of the aircraft, driving the front propeller to deflect downward until the thrust axis of the front propeller forms a set acute angle with the horizontal plane of the fuselage, and at the same time controls the rear engine located at the tail of the aircraft to keep the thrust axis of the rear propeller always perpendicular to the horizontal plane of the fuselage.

[0020] Preferably, the deflection control module comprises:

[0021] The power distribution unit is used to control the output power of the front engine and the rear engine so that the power of the front propeller is greater than the power of the rear propeller.

[0022] Preferably, the front engine is connected to the power distribution device via a front interactive transmission shaft, and the rear engine is connected to the power distribution device via a rear interactive transmission shaft, and power is redistributed to the front propeller and the rear propeller via the power distribution device.

[0023] Preferably, the positions of the front engine and the rear engine on the aircraft are configured so that when the aircraft performs short takeoff and landing, the distance from the center of gravity of the aircraft to the thrust axis of the front propeller is smaller than the distance from the center of gravity of the aircraft to the thrust axis of the rear propeller.

[0024] The present application reduces the aerodynamic interference of the rotor on the wing during the short-distance takeoff of the tilt-rotor aircraft by adjusting the position of the engine, increases the longitudinal control torque during the short-distance takeoff of the tilt-rotor aircraft, and improves the short-distance take-off efficiency of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flow chart of a preferred embodiment of the short take-off method applicable to a tilt-rotor aircraft of the present application.

[0026] Figure 2 This application Figure 1 A perspective view of the rotor deflection control structure of a tilt-rotor aircraft during short takeoff according to the illustrated embodiment.

[0027] Figure 3 for Figure 2 Top view of the illustrated embodiment.

[0028] Figure 4 This is a schematic diagram of the distance between each rotor axis and the center of gravity of a tilt-rotor aircraft in short takeoff state.

[0029] Among them, 1-fuselage, 2-wing, 3-tail, 4-front engine system, 5-rear engine system, 6-power distribution device, 7-front interactive transmission shaft; 8-rear interactive transmission shaft, 9-front engine, 10-front engine propeller, 11-rear engine, 12-rear engine propeller. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the implementation of this application will be described in more detail in combination with the drawings in the implementation of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described implementation is a part of the implementation of this application, not all of the implementations. The implementation described below with reference to the drawings is exemplary and is intended to be used to explain this application, and cannot be understood as a limitation on this application. Based on the implementation in this application, all other implementations obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The implementation of this application is described in detail below in combination with the drawings.

[0031] In a first aspect, the present application provides a short takeoff method applicable to a tilt-rotor aircraft, such as Figure 1 As shown, it mainly includes:

[0032] Step S1, receiving a short take-off signal of a tilt-rotor aircraft;

[0033] Step S2, controlling the front engine 9 located at the nose to deflect, driving the front propeller 10 to deflect downward until the tension axis of the front propeller 10 forms a set acute angle with the horizontal plane of the fuselage, and at the same time controlling the rear engine 11 located at the tail to keep the tension axis of the rear propeller 12 always perpendicular to the horizontal plane of the fuselage.

[0034] refer to Figure 2 and Figure 3 The aircraft is composed of a fuselage 1, wings 2, tail 3, landing gear and a power unit. The power unit refers to the two engines equipped on the aircraft, as well as the rotors driven by the engines and the interactive transmission shafts, which respectively constitute the front system 4 and the rear system 5. The two engines are located at the head and tail of the aircraft, respectively, and are called the front engine 9 and the rear engine 11. The two engines can be tilted within a certain angle range to drive the front propeller 10 and the rear propeller 12 to deflect respectively. During the short-distance takeoff process, the front engine 9 is deflected downward or forward while the rear engine 11 is deflected upward under the premise of ensuring the safety of the propeller. It can be understood that when the tilt-rotor aircraft is on the ground, the rotation planes of the two propellers are parallel to the ground. Therefore, after receiving the short-distance takeoff signal, the front propeller 10 is deflected downward, and the rear propeller 12 remains unchanged in its initial state. The aircraft is accelerated by the horizontal force of the front system 4, the takeoff speed is reduced by the vertical forces of the front system 4 and the rear system 5, and the longitudinal balance of the aircraft is controlled by the torque of the rear system 5. This enables short takeoff operations of the tilt-rotor aircraft.

[0035] During short takeoff and landing, the airflow of the front launch system 4 affects the aerodynamic force of the fuselage 1 and a portion of the wing 2, while the airflow through the rear launch system 5 does not affect the aerodynamic force of the wing. A comprehensive analysis shows that the aerodynamic interference of the rotor on the wing is greatly reduced compared to the design of the V-22 aircraft.

[0036] In some optional implementations, step S2 further includes:

[0037] The output power of the front engine 9 and the rear engine 11 is controlled so that the power of the front propeller 10 is greater than the power of the rear propeller 12 .

[0038] In some optional embodiments, the front engine 9 is connected to the power distribution device 6 via the front interactive transmission shaft 7, and the rear engine 11 is connected to the power distribution device 6 via the rear interactive transmission shaft 8, and the power is redistributed to the front propeller 10 and the rear propeller 12 through the power distribution device 6.

[0039] In some optional embodiments, the positions of the front engine 9 and the rear engine 11 on the aircraft are configured so that, when the aircraft performs short takeoff and landing, the distance from the center of gravity of the aircraft to the thrust axis of the front propeller 10 is smaller than the distance from the center of gravity of the aircraft to the thrust axis of the rear propeller 12.

[0040] like Figure 4 As shown, during short-distance takeoff and landing, the tension axis of the rear launch system 5 is farther from the moment arm of the center of gravity, that is, L2>L1. Therefore, the change of the tension of the rear launch system 5 will produce an obvious longitudinal control torque. Such a design greatly improves the controllability of short-distance takeoff and lays a foundation for increasing the take-off weight of the aircraft.

[0041] The second aspect of the present application provides a short take-off system for a tilt-rotor aircraft corresponding to the above method, mainly comprising:

[0042] A short take-off signal receiving module is used to receive a short take-off signal of a tilt-rotor aircraft;

[0043] The deflection control module is used to control the deflection of the front engine 9 located at the nose of the aircraft, driving the front propeller 10 to deflect downward until the thrust axis of the front propeller 10 forms a set acute angle with the horizontal plane of the fuselage, and at the same time controls the rear engine 11 located at the tail of the aircraft to keep the thrust axis of the rear propeller 12 always perpendicular to the horizontal plane of the fuselage.

[0044] The front engine 9 located at the nose of the aircraft is controlled to deflect, thereby driving the front propeller 10 to deflect, so that the tension axis of the front propeller 10 forms a set acute angle with the horizontal plane of the fuselage. At the same time, the rear engine 11 located at the tail of the aircraft is controlled to deflect, thereby driving the rear propeller 12 to deflect, so that the tension axis of the rear propeller 12 is perpendicular to the horizontal plane of the fuselage.

[0045] In some optional embodiments, the deflection control module includes:

[0046] The power distribution unit is used to control the output power of the front engine 9 and the rear engine 11 so that the power of the front propeller 10 is greater than the power of the rear propeller 12.

[0047] In some optional embodiments, the front engine 9 is connected to the power distribution device 6 via the front interactive transmission shaft 7, and the rear engine 11 is connected to the power distribution device 6 via the rear interactive transmission shaft 8, and the power is redistributed to the front propeller 10 and the rear propeller 12 through the power distribution device 6.

[0048] In some optional embodiments, the positions of the front engine 9 and the rear engine 11 on the aircraft are configured so that when the aircraft performs short takeoff and landing, the distance from the center of gravity of the aircraft to the thrust axis of the front propeller 10 is smaller than the distance from the center of gravity of the aircraft to the thrust axis of the rear propeller 12.

[0049] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A short takeoff method suitable for a tilt-rotor aircraft, characterized in that: include: Step S1, receiving a short take-off signal of a tilt-rotor aircraft; Step S2, controlling the front engine (9) located at the nose of the aircraft to deflect, driving the front propeller (10) to deflect downward until the tension axis of the front propeller (10) forms a set acute angle with the horizontal plane of the fuselage, and at the same time controlling the rear engine (11) located at the tail of the aircraft to keep the tension axis of the rear propeller (12) always perpendicular to the horizontal plane of the fuselage.

2. The short takeoff method for a tilt-rotor aircraft according to claim 1, characterized in that: Step S2 further comprises: The output power of the front engine (9) and the rear engine (11) is controlled so that the power of the front propeller (10) is greater than the power of the rear propeller (12).

3. The short takeoff method for a tilt-rotor aircraft according to claim 2, characterized in that: The front engine (9) is connected to the power distribution device (6) via the front interactive transmission shaft (7), and the rear engine (11) is connected to the power distribution device (6) via the rear interactive transmission shaft (8), and the power is redistributed to the front propeller (10) and the rear propeller (12) via the power distribution device (6).

4. The short takeoff method for a tilt-rotor aircraft according to claim 1, characterized in that: The positions of the front engine (9) and the rear engine (11) on the aircraft are configured such that, when the aircraft is performing short takeoff and landing, the distance from the center of gravity of the aircraft to the thrust axis of the front propeller (10) is smaller than the distance from the center of gravity of the aircraft to the thrust axis of the rear propeller (12).

5. A short take-off system suitable for a tilt-rotor aircraft, characterized in that: include: A short take-off signal receiving module is used to receive a short take-off signal of a tilt-rotor aircraft; The deflection control module is used to control the deflection of the front engine (9) located at the nose of the aircraft, driving the front propeller (10) to deflect downward until the tension axis of the front propeller (10) forms a set acute angle with the horizontal plane of the fuselage, and at the same time controls the rear engine (11) located at the tail of the aircraft to keep the tension axis of the rear propeller (12) always perpendicular to the horizontal plane of the fuselage.

6. The short take-off system for a tilt-rotor aircraft according to claim 1, characterized in that: The deflection control module comprises: The power distribution unit is used to control the output power of the front engine (9) and the rear engine (11) so that the power of the front propeller (10) is greater than the power of the rear propeller (12).

7. The short take-off system for a tilt-rotor aircraft according to claim 6, characterized in that: The front engine (9) is connected to the power distribution device (6) via the front interactive transmission shaft (7), and the rear engine (11) is connected to the power distribution device (6) via the rear interactive transmission shaft (8), and the power is redistributed to the front propeller (10) and the rear propeller (12) via the power distribution device (6).

8. The short take-off system for a tilt-rotor aircraft according to claim 5, characterized in that: The positions of the front engine (9) and the rear engine (11) on the aircraft are configured such that, when the aircraft is performing short takeoff and landing, the distance from the center of gravity of the aircraft to the thrust axis of the front propeller (10) is smaller than the distance from the center of gravity of the aircraft to the thrust axis of the rear propeller (12).

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