A fixed-axle sub-wing adaptive spoiler blow-jet flap

Abstract

The present application belongs to the field of air flow, and relates to a blowing flap of a fixed-axle sub flap adaptive spoiler. The blowing flap comprises a fixed wing surface, a fixed rotating shaft, a main flap, a sub flap, a main flap blowing gap, a sub flap blowing gap, a spoiler rotating shaft and a spoiler. The main flap and the sub flap are downwardly deflected at a large angle, the spoiler is downwardly deflected to be attached to the upper surface of the sub flap, the blowing gaps on the sub flap and the main flap work in a certain blowing momentum coefficient matching relationship, the maximum lift coefficient of the aircraft is greatly improved, the lift-drag ratio is very high, and the super-circulation effect is realized.

Description

Technical Field

[0001] This invention relates to the field of influencing the airflow over the surface of an aircraft by affecting the boundary laminar flow, specifically to a blown flap of a fixed-axis fixed sub-flap adaptive spoiler. Background Technology

[0002] When operating and using aircraft, it is desirable to reduce takeoff and landing speeds and shorten takeoff and landing distances. This requires the design of lift-enhancing devices to increase the maximum lift coefficient of the aircraft at low altitudes and low speeds, thereby improving the aerodynamic characteristics of the aircraft at low altitudes and low speeds.

[0003] Traditional lift enhancement devices for aircraft typically employ simple, double-slit, multi-slit, or fullerer mechanical designs. To generate a higher lift coefficient and improve the aerodynamic characteristics of the aircraft, multi-element mechanical lift enhancement devices can be used. However, such systems generally involve complex deflection mechanisms and track structures, resulting in significant drawbacks such as large overall system weight, high manufacturing costs, and low operational reliability.

[0004] Designing efficient high-lift systems is a challenging task in the aerospace industry. Modern civil aircraft require complex, multi-element high-lift systems to increase the lift coefficient to compensate for the low-speed flight during takeoff and landing. Modern high-lift design has shifted towards reducing complexity, weight, and maintenance costs while maintaining acceptable lift levels, which benefits the overall cost of the aircraft. Two commonly used mechanical lift-enhancing flap mechanisms are the simple hinge and the Fuller flap mechanism.

[0005] Simple hinged mechanisms are commonly used in McDonnell Douglas aircraft. A simple hinged flap is characterized by a simple mechanism connected to a fixed hinge and purely rotational motion. It has a simple mechanical structure and is lightweight, but its rotational trajectory is very limited. To achieve greater flap retraction, the hinged flap's fulcrum must be far from the wing, resulting in a large flap pylon fairing and cruise drag loss. Furthermore, due to the kinematic constraints of the simple hinged mechanism, optimal landing and takeoff configurations may not be achievable on the same trajectory.

[0006] Fuller flaps are widely used trailing-edge lift enhancement devices on civil aircraft. They are characterized by an almost translational motion during takeoff to increase wing area and a rotational motion during landing to increase wing camber, providing optimal aerodynamic efficiency for both takeoff and landing. However, this mechanism is more complex than a simple hinged flap. Three types of mechanisms are typically used on Fuller flaps: linkage systems, track systems, and hybrid systems; however, all of these types of systems tend to be heavy, costly, and have lower reliability and maintainability.

[0007] Adaptive drooping hinged flaps have been used on multiple aircraft. They integrate a downward-deflecting spoiler with a simple hinged flap, which is a single piece deflecting around a fixed axis. Mechanically, adaptive drooping hinged flaps are simpler than traditional Fuller flaps, requiring fewer moving parts and thus significantly reducing weight. The multi-functional spoiler allows for rearward deflection as a speed brake during landing and can deflect downward during takeoff and landing to adjust the gap of the single-slotted flap; this gap is called the slot width. In takeoff configuration, the spoiler deflects downward, causing the wake and boundary layer to converge, primarily to improve the wing's lift-to-drag ratio and achieve a reasonable maximum lift coefficient. In landing configuration, the spoiler deflects downward and adjusts to a reasonable slot width, preventing the wake and boundary layer from converging, placing the flap in a high-lift mode. Its primary purpose is to improve the wing's maximum lift coefficient, but the lift-to-drag ratio is also significantly reduced. When the spoiler of this type of flap deflects downwards during landing, a reasonable gap size must be maintained between it and the flap; otherwise, the aerodynamic performance will be severely degraded, and it will fail to function properly. At the same time, this adaptive drooping hinge flap needs to be used in conjunction with devices such as leading-edge slats to increase the wing's stall angle of attack, thereby effectively increasing the maximum lift coefficient.

[0008] The aforementioned mechanical lift booster has the advantage of lower manufacturing and operating costs. However, the flap deflection of a mechanical lift booster is generally no greater than 45°. On the one hand, excessive deflection can cause airflow separation, and the amount of the lift booster's retreat is limited by structural strength and rigidity, thus restricting its lift-boosting effect. On the other hand, the deployment of the lift booster increases flight drag, significantly impacting the aircraft's go-around and climb performance.

[0009] Amphibious aircraft are short takeoff and landing (STOVL) aircraft. Besides taking off and landing on land, they must also be able to utilize water for takeoff and landing. Therefore, in addition to good flight performance, amphibious aircraft should also possess a certain degree of seaworthiness to ensure safe maneuverability on water under certain wind and wave conditions, as well as safe takeoff and landing. For amphibious aircraft, wave resistance is a crucial factor affecting sortie rate. Wave resistance is systematically studied from aerodynamic, hydrodynamic, and ocean wave environment perspectives. Improving the wave resistance and waterplane stability of amphibious aircraft can be achieved by reducing the aircraft's waterplane speed. Therefore, ensuring a low stall speed and high usable lift during waterplane takeoff and landing are two essential considerations. Thus, to enhance the wave resistance of amphibious aircraft and improve the performance of lift-enhancing devices, flap boundary layer control technology is commonly employed.

[0010] The blown flap scheme, employing boundary layer blowing for lift enhancement, overcomes the problems of traditional mechanical lift enhancement devices. This type of blown flap lift enhancement device is typically based on a simple flap structure without a duct, with a blowing slot at the head of the movable surface or the trailing edge of the fixed surface, sealing the movable surface or flap to the fixed surface. Airflow injects energy into the boundary layer through the blowing slot, thereby improving the flow field after the movable surface deflects and increasing the maximum lift coefficient. This traditional blown flap can be set to a maximum deflection of 80°, eliminating airflow separation on the flap through boundary layer control technology, thus achieving a high lift coefficient. However, if a traditional blown flap lift enhancement device malfunctions, the simple flap deflected at a large angle will rapidly experience airflow separation, causing a rapid and significant decrease in the aircraft's maximum lift coefficient. This leads to an imbalance between lift and gravity, a rapid decrease in flight altitude, and serious impacts on flight safety at low altitudes and low speeds. The drawbacks of the blown flap lift enhancement method make its design difficult to widely apply. Summary of the Invention

[0011] Purpose of the invention

[0012] To address the inherent problems of traditional blown flaps, expand their application range, broaden the types of lift-enhancing devices available for short takeoff and landing aircraft, and improve the adaptability of special aircraft in special and complex environments, this invention provides a safe, efficient, and practical blown flap with a fixed-axis fixed sub-flap and adaptive spoiler.

[0013] Technical solution

[0014] A fixed-axis, self-adaptive spoiler-equipped blowing flap includes a fixed airfoil 1, a fixed pivot 2, a main flap 3, a sub-flap 4, a main flap blowing slot 5, a sub-flap blowing slot 6, a spoiler pivot 8, and a spoiler 9. The sub-flap 4 is fixed to the leading edge of the main flap 3, and both the main flap 3 and the sub-flap 4 deflect around the fixed pivot 2 simultaneously. A spoiler pivot 8 is located at the trailing edge of the fixed airfoil 1, and the spoiler 9 deflects through the spoiler pivot 8. The main flap 3 has a main flap blowing slot 5, and the sub-flap 4 has a sub-flap blowing slot 6. When the main flap 3 and the sub-flap 4 deflect, the spoiler 9 deflects downwards and adheres to the upper surface of the sub-flap 4, forming a flap channel between the main flap 3 and the sub-flap 4. Air is blown through the main flap blowing slot 5 and the sub-flap blowing slot 6, creating supercirculation, increasing the lift of the blowing flap and reducing drag.

[0015] Furthermore, the deflection angle of the spoiler 9 is set according to functional requirements.

[0016] Furthermore, the flap air slit 5 and the sub-flap air slit 6 are located on the upper surface of the head of the main flap 3 and the upper surface of the sub-flap 4, respectively. The main flap air slit 5 is positioned at the outlet of the sub-slit channel formed by the sub-flap 4 and the main flap 3, achieving optimal aerodynamic effect and efficiency when the main flap 3 is in cruise mode and sealed against the spoiler 9. The sub-flap air slit 6 is positioned at the trailing edge of the sub-flap 4, achieving optimal aerodynamic effect and efficiency when the sub-flap 4 is in the high-lift mode of the air slit system operation and flap deflection and sealed against the spoiler 9.

[0017] Furthermore, the sum of the blowing momentum coefficients of the main flap blowing slot 5 and the sub-flap blowing slot 6 is the blowing momentum coefficient of the blowing flap. When the ratio of the blowing momentum coefficients of the main flap blowing slot 5 to the sub-flap blowing slot 6 is between 1:1.5 and 1:2.5, the aerodynamic effect and efficiency are optimal, and the blowing momentum coefficient of the blowing flap can be minimized.

[0018] Furthermore, both the main flap air slit 5 and the sub-flap air slit 6 are parallel channel sections that smoothly transition tangentially to the moving surface at the outlet, ensuring the directionality of the blown airflow.

[0019] Furthermore, the main flap 3, the sub-flaps 4, and the spoiler 9 are made of metal or composite materials.

[0020] Furthermore, the width of the flap slot is 0.5%-2.0% of the local wing chord length.

[0021] Furthermore, when the main flap 3 and the sub-flaps 4 are retracted to the cruise position, the spoiler 9 does not deflect, and the airfoils maintain an aerodynamic seal, thus meeting the requirements of the aircraft's cruise aerodynamic configuration.

[0022] Furthermore, when the blown flaps are in the mechanical lift enhancement mode where the blown system is not working and the flaps are deflected, the spoiler and the sub-flaps 4 form the main slot, and the sub-flaps 4 and the main flaps 3 form the flap sub-slots. After the main flap deflection is reduced relative to the high lift mode, the aircraft can obtain a certain high lift characteristics through a relatively simple lift enhancement device without activating the boundary layer lift enhancement system. This reduces the utilization rate of the blown system, reduces the extreme requirements for the safety and reliability of the blown system, and reduces the cost and weight of the aircraft.

[0023] The beneficial effects of this application are as follows:

[0024] When the blowing system is working, the blowing flap provided by this invention adopts a large downward deflection of the main flap and the sub-flaps, while the spoiler is deflected downward until it is in contact with the upper surface of the sub-flaps. The blowing slots on the sub-flaps and the main flaps work with a certain blowing momentum coefficient matching relationship, which greatly improves the maximum lift coefficient of the aircraft and has an extremely high lift-to-drag ratio, realizing the supercirculation effect.

[0025] Traditional flaps maintain a certain gap between the spoiler and the flap during high-lift modes such as landing to achieve high lift. The spoiler in the blown flap provided by this invention is specially designed so that, during the high-lift mode when the blowing system is working and the flap is deflected, the spoiler deflects downwards until it is in contact with the upper surface of the sub-flap.

[0026] The blowing flap mechanism provided by this invention is that, during the high lift mode of the blowing system operation and flap deflection, the turbulence is deflected downwards, the main flap slot is closed, and the sub-slots are retained. Through the arrangement of the flap slots and blowing slots, the pressure on the wing is redistributed, the separation flow on the wing surface is eliminated, the direction of the normal force is optimized, and supercirculation is achieved, thereby reducing flight drag.

[0027] When the blowing system is working, the blowing flap provided by this invention adopts reasonable and optimized blowing slot positions on the sub-flaps and main flaps, which improves the overall lift coefficient of the blowing flap and reduces its drag coefficient. Thus, under a certain blowing momentum coefficient and lift coefficient, a better lift-to-drag ratio is obtained, thereby achieving better aerodynamic performance and reducing the performance requirements of the aircraft's thrust system.

[0028] When the blowing system is working, the blowing flap provided by this invention operates with an optimized blowing momentum coefficient matching relationship between the sub-flaps and the main flaps. This reduces the total blowing momentum coefficient requirement while maintaining the same lift coefficient requirement, thereby reducing the energy demand of the blowing flap system on the power system and improving the overall efficiency of the aircraft.

[0029] When the blowing system is working, the blowing flap provided by this invention has blowing slots set on the sub-flaps and the main flap respectively, and the spoiler is biased to fit and seal the upper surface of the sub-flaps. This distributed blowing method makes the boundary layer control efficiency on the wing surface higher, thereby increasing the available flap deflection and obtaining a larger lift coefficient to meet the needs of the aircraft when flying at low altitude and low speed.

[0030] The blowing flap provided by this invention adopts a simple mechanical structure. The sub-flaps are fixed to the leading edge of the main flaps. The sub-flaps and the main flaps rotate around a fixed axis. The spoiler also adopts a fixed axis for rotation. The flap movement mechanism and structure are simple and can be applied to a variety of manufacturing materials.

[0031] The blown flap provided by this invention has higher efficiency, expands the application range of this flap, broadens the types of lift enhancement devices that can be selected for short takeoff and landing aircraft, and can improve the adaptability of special aircraft in special and complex environments.

[0032] When the blowing system malfunctions during critical flight phases such as takeoff and landing, the blowing flap provided by this invention can quickly deflect the spoiler to the mechanical lift-enhancing position, restoring the main and sub-slots of the flap to the ideal mechanical lift-enhancing configuration. This prevents a sudden and significant decrease in the aircraft's lift, reducing the safety risks associated with sudden and significant reductions in lift and drag.

[0033] This invention provides a useful, more adaptable, and more efficient blown flap with an innovative approach. The device involved in this invention has a simple structure and is lightweight, making it easily applicable to aircraft lift enhancement devices, thus possessing broader application prospects. It has strong lift enhancement capabilities and can significantly improve the lift-to-drag ratio of aircraft, reducing the aircraft's demand on the power plant. The device involved in this invention has wide applications and can be used in aerospace and other fluid dynamics-related fields. Attached Figure Description

[0034] Figure 1 The diagram shows the high-lift state of the blown flap in operation of the blown system and the flap deflection, as provided by the present invention.

[0035] Figure 2 This is a conventional blow-through flap design diagram in contrast to the present invention.

[0036] Figure 3 The diagram illustrates the mechanical high-lift mode of the blown flap provided by this invention when the blown system is not working and the flap deflects.

[0037] Figure 4 The diagram shows the cruise mode provided by the present invention with the blowing flap inactive and the flap not deflecting.

[0038] Figure 5 This is a visual illustration of the switching between different operating modes of the blow-off flap provided by the present invention.

[0039] Figure 6 The flow pattern of the blown flap provided by the present invention under high lift conditions of blown system operation and flap deflection.

[0040] Figure 7 A diagram showing the lift coefficient of the blown flap provided by the present invention under high lift conditions of blown system operation and flap deflection;

[0041] Figure 8 The diagram shows the lift-to-drag ratio of the blown flap provided by the present invention under high lift conditions when the blown system is working and the flap is deflected. Detailed Implementation

[0042] The present invention will be further described below with reference to embodiments. The following description represents only a portion of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0043] Figure 1 In the middle, (1) fixed wing surface, (2) fixed pivot, (3) main flap, (4) sub flap, (5) main flap air slit, (6) sub flap air slit, (7) air slit jet, (8) spoiler pivot, (9) spoiler.

[0044] Figure 1 In the middle, the main flap and the sub-flaps deflect downward at a large angle, while the spoiler deflects downward until it is in contact with the upper surface of the sub-flaps. The nozzle slots on the sub-flaps and the main flap operate with a certain blowing momentum coefficient matching relationship.

[0045] Figure 7 Compared with the lift coefficient of traditional blown flaps, the present invention can provide a greater lift coefficient with the same blown momentum coefficient. It should be noted that the momentum coefficient of the blown flap provided by the present invention is (5) the sum of the momentum coefficients of the main flap blown slot and (6) the sub-flap blown slot.

[0046] Figure 8 Compared with the lift coefficient of traditional blown flaps, the present invention can provide a greater lift-to-drag ratio with the same blown momentum coefficient. It should be noted that the momentum coefficient of the blown flap provided by the present invention is (5) the sum of the momentum coefficients of the main flap blown slot and (6) the sub-flap blown slot.

[0047] Example 1:

[0048] This embodiment provides a blowing flap with a fixed-axis sub-flap adaptive spoiler, such as... Figure 1 As shown, the blowing flaps are in a high-lift state with the blowing system operating and the flaps deflecting. When the blowing system is operating, the blowing slots on the sub-flaps and the blowing slots on the main flaps operate with a certain amount and a certain matching relationship of blowing momentum coefficients to achieve boundary layer control in this state.

[0049] In this operating state, the main flap and sub-flaps are deflected downward at a large angle, while the spoiler is deflected downward until it is in contact with the upper surface of the sub-flaps. The nozzles on the sub-flaps and the nozzles on the main flaps operate with a certain blowing momentum coefficient matching relationship.

[0050] The working principle of this invention is as follows: during the high-lift mode of the blowing system operation and flap deflection, the turbulence is deflected downwards, closing the main flap slots while retaining the sub-slots. Through the arrangement of the flap slots and distributed blowing slots, the pressure on the wing is redistributed, eliminating the separated flow on the wing surface, significantly increasing the maximum lift coefficient of the flaps, and achieving supercirculation. At the same time, the direction of the normal force is optimized, reducing flight drag and improving the lift-to-drag ratio.

[0051] The innovative design of this invention, which employs a downward-biased sealed spoiler, a distributed air duct arrangement, and optimized flap duct positions, results in higher boundary layer control efficiency on the wing surface and better aerodynamic performance.

[0052] Figure 2 This is a typical cross-sectional design of a traditional blown flap. This blown flap adopts a simple deflection design, and the blown slot is usually located on the trailing edge of the fixed airfoil or the upper surface of the flap head. This blown slot eliminates the separation flow on the upper surface of the flap during operation, thereby improving the lift coefficient of the flap. Figure 7 and Figure 8 The performance curves of the blown flaps are shown.

[0053] It should be noted that the momentum coefficient of the blowing flap provided by the present invention is the sum of the momentum coefficients of the blowing slot of the main flap and the blowing slot of the sub-flap.

[0054] Figure 7 The lift coefficient curves of the blown flap provided by the present invention under high lift conditions of blown system operation and flap deflection are shown. The horizontal axis is the blown momentum coefficient, and the vertical axis is the lift coefficient of the blown flap. The point where the curvature of the lift coefficient curve is the maximum corresponds to the critical blown momentum coefficient of this flap. Figure 7 The accompanying diagram provides a comparison between the blown flap of this invention and a conventional blown flap. The blown flap provided by this invention has a smaller critical blown momentum coefficient. Compared to conventional blown flaps, the blown flap provided by this invention can provide a larger lift coefficient near the critical blown momentum coefficient. The blown flap provided by this invention can provide a larger lift coefficient for the same blown momentum coefficient.

[0055] Figure 8 The lift-to-drag ratio curves of the blown flap provided by the present invention under high lift conditions of blown system operation and flap deflection are shown. The horizontal axis is the blown momentum coefficient and the vertical axis is the lift-to-drag ratio of the blown flap. Figure 8The accompanying text provides a comparison between the blown flap of this invention and a conventional blown flap. Throughout the entire range, the blown flap provided by this invention exhibits a high lift-to-drag ratio under the same blown momentum coefficient. When the blown momentum coefficient exceeds the critical blown momentum coefficient, the lift-to-drag ratio of both the conventional blown flap and the blown flap provided by this invention increases rapidly. With increasing blown momentum coefficient, the conventional blown flap no longer provides a lift-to-drag ratio, and may even slightly decrease. However, with increasing blown momentum coefficient, the lift-to-drag ratio of the blown flap provided by this invention continues to increase and is significantly higher than that of the conventional blown flap, demonstrating a clear advantage.

[0056] The blown flap provided by this invention employs several innovative designs. Under high lift conditions with both the blown system operating and the flap deflecting, its lift coefficient and lift-to-drag ratio are higher than those of conventional blown flaps at the same blown momentum coefficient. The blown flap provided by this invention has a smaller critical blown momentum coefficient, exhibiting a significant advantage in lift coefficient at low blown momentum coefficients and a significant advantage in lift-to-drag ratio at high blown momentum coefficients.

[0057] Example 2:

[0058] This embodiment provides a mode for converting the blown flap of a fixed-axis sub-flap adaptive spoiler into a high-efficiency mechanical lift-enhancing device, such as... Figure 3 As shown, the blowing flaps are in a high-lift state with the blowing system inactive and the flaps deflected. When the blowing system is inactive, the blowing slots on the sub-flaps and the blowing slots on the main flaps cease operation.

[0059] In this embodiment, when the blown flaps experience a blown system failure during critical flight phases such as takeoff and landing, the spoilers are quickly deflected to a mechanical lift-enhancing position or other required positions. This restores the main and sub-slots of the flaps to the ideal or required lift-enhancing configuration, preventing a sudden and significant drop in lift and mitigating the safety risks associated with such a sudden and significant decrease in lift and drag. Similarly, when the aircraft operates in an ideal environment and the blown system is not required, the aircraft can fly normally with high lift in a state where the blown system is not in operation and the flaps are deflected. This reduces the frequency of blown system usage, lowers the extreme requirements for the safety and reliability of the blown system, and reduces the cost and weight of the aircraft.

[0060] Example 3:

[0061] This embodiment provides a mode for the blowing flap of a fixed-axis fixed sub-flap adaptive spoiler to switch to cruise mode, such as... Figure 3As shown, the blown flaps are in a cruise state where the blown system is not active and the flaps are not deflected. When the blown system is not active, the blown slots on the sub-flaps and the main flaps cease operation. When the main flaps and sub-flaps retract to the cruise position, the spoilers do not deflect, thus maintaining an aerodynamic seal between the wing surfaces and meeting the requirements of the aircraft's cruise aerodynamic configuration. Similarly, based on this state, by slightly deflecting the main flaps and sub-flaps (e.g., ±4°), combined with a small adaptive deflection of the spoilers to maintain the aerodynamic seal between the spoilers and the main flaps, the aircraft can achieve trailing edge camber in cruise mode. Lift increase and drag reduction in cruise configuration are achieved through camber control along the wing's trailing edge extension.

[0062] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein. The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A blowing flap with a fixed-axis sub-flap adaptive spoiler, characterized in that, The system includes a fixed airfoil, a fixed pivot, a main flap, a sub-flaps, a main flap air slit, a sub-flaps air slit, a spoiler pivot, and a spoiler. The sub-flaps are fixed to the leading edge of the main flap, and both the main flap and the sub-flaps deflect around the fixed pivot simultaneously. A spoiler pivot is located at the trailing edge of the fixed airfoil, and the spoiler deflects through the spoiler pivot. The main flap has a main flap air slit, and the sub-flaps have sub-flaps air slits. When the main flap and the sub-flaps deflect, the spoiler deflects downward and comes into contact with the upper surface of the sub-flaps, forming a flap slit between the main flap and the sub-flaps, allowing air to flow from the main flap. The main flap and sub-flaps blow air through the air gaps to create supercirculation, increasing the lift of the blown flaps and reducing drag. The main flap blown air gap and sub-flaps blown air gap are located on the upper surface of the main flap tip and the upper surface of the sub-flaps, respectively. The main flap blown air gap is located at the outlet of the sub-gap formed by the sub-flaps and the main flap, achieving the best aerodynamic effect and efficiency when the main flap is in cruise mode and sealed against the spoiler. The sub-flaps blown air gap is located at the trailing edge of the sub-flaps, between the sub-flaps and the spoiler when the blown air system is working and the flaps are in high-lift mode of deflection.

2. The blown flap as described in claim 1, characterized in that, The deflection angle of the spoiler is set according to functional requirements.

3. The blown flap as described in claim 1, characterized in that, The sum of the blowing momentum coefficients of the main flap blowing slot and the sub-flap blowing slot is the blowing momentum coefficient of the blowing flap. When the ratio of the blowing momentum coefficients of the main flap blowing slot to the sub-flap blowing slot is between 1:1.5 and 1:2.5, the aerodynamic effect and efficiency are optimal, and the blowing momentum coefficient of the blowing flap can be minimized.

4. The blown flap as described in claim 1, characterized in that, The main flap air slit and the sub-flap air slit are both parallel channel sections that smoothly transition tangentially to the moving surface at the outlet to ensure the directionality of the blown airflow.

5. The blown flap as described in claim 1, characterized in that, The main flap, sub-flaps, and spoilers are made of metal or composite materials.

6. The blown flap as described in claim 1, characterized in that, The width of the flap slot is 0.5%-2.0% of the local wing chord length.

7. The blown flap as described in claim 1, characterized in that, When the main flaps and sub-flaps are retracted to the cruise position, the spoilers do not deflect, and the airfoils maintain an aerodynamic seal to meet the requirements of the aircraft's cruise aerodynamic configuration.

8. The blown flap as described in claim 1, characterized in that, When the blown flaps are in the mechanical lift enhancement mode where the blown system is not working and the flaps are deflected, the spoiler and the sub-flaps form the main slot, and the sub-flaps and the main flaps form the flap sub-slot. After the deflection of the main flaps is reduced relative to the high lift mode, the aircraft can obtain a certain high lift characteristics through a relatively simple lift enhancement device without activating the boundary layer lift enhancement system, thereby reducing the utilization rate of the blown system.

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