WO2004092009A1

WO2004092009A1 - A Wing ASSEMBLY CAPABLE OF INCREASIGN THE LIFT AND THE ANGLE OF STALL

Info

Publication number: WO2004092009A1
Application number: PCT/CN2003/001035
Authority: WO
Inventors: Shangxiang Zhu
Original assignee: Shangxiang Zhu
Priority date: 2003-01-17
Filing date: 2003-12-04
Publication date: 2004-10-28
Also published as: CN1517269A; AU2003289606A1; CN100513256C

Abstract

A wing assembly has a sheet structure for increasing the lift and the angle of stall. The sheet structure locates above the wing or slopes upwards. The upper sheet can pivot with the trailing edge of the wing. The anhedral of slant sheet also can vary. The sheet is capable of being released or retracted or changed its configuration as required. A duct is formed between the sheet and the upper surface of the wing, and the airflow in the said duct accelerates and has great kinetic energy, which significantly increases the maximum lift coefficient and the angle of stall. Before optimizing, the maximum lift coefficient can increase more than 70% and the angle of stall can increase over 18 degree. The principle of present invention is novel and the structure thereof is simple, so it can be widely used in civil aircraft military aircraft and other machinery which can move in the fluid.

Description

Canopy wing for increasing lift and stall angle of attack

The present invention relates to aeronautical technology, and more particularly, to a canopy wing that can be used in an aircraft to increase lift and stall angle of attack. Background technique

In order to obtain sufficient lift when the aircraft is flying at low speed, almost all aircraft are equipped with lifting devices. The prior art lifting devices are mainly as follows: The most common devices are various types of flaps, including slotted flaps in the early stages of aircraft development, and Fuller flaps and Kruger flaps, which were later invented in succession. Fuller flaps are flaps mounted on the trailing edge of the wing. Kruger flaps are flaps mounted on the leading edge of the wing. There are many types by structure, such as split flaps, simple flaps, slotted flaps. The main function of these flaps is to increase the camber of the airfoil, to delay the separation of the airflow above the wing, thereby increasing the lift coefficient, especially the stall angle of attack and the maximum lift coefficient. In addition, there are devices for jet flaps and devices for suction flaps, which are used to control the surface layer and further delay the separation of airflow. The above device has achieved good results, which has greatly increased the maximum lift coefficient and stall angle of attack of the aircraft. In order to further increase the lift, in order to shorten the take-off and run-off distance of the aircraft and have better stall characteristics, the jet flap technology is theoretically very effective, but the structure is complex, and it is necessary to draw the jet from the engine to the wing, which consumes With energy, high-temperature gas is introduced to the surface of the wing, which requires high materials and structures, so it has not been widely used so far. In terms of how to obtain a higher lift coefficient, many scientists at home and abroad have made great efforts in recent years. Among them, there are U.S. patents 563461, 5772155, 63186771, and 6302360 which are closest to the object of the present invention. These patents disclose a method of using vortices to change the airflow characteristics of the upper airfoil of the wing in an attempt to delay the separation of the airflow and increase the stall angle of attack and the maximum lift coefficient. Domestic patents 94226631, 98201185, and 89207887 have proposed methods of using vortex trapping wings, jet power, and ring wings to increase the lift. However, the effect of all the above efforts is small. Among them, the vortex generator device is used to change the laminar flow field to a turbulent flow field at the leading edge or upper airfoil of the wing, so that the airflow on the upper airfoil can obtain greater kinetic energy, realize delayed separation and maximize the lift coefficient. Increased desire. But in fact, it did not work as expected, because the result of this increase was to pay a lot of resistance for the price, and this effect

1

Confirm this Not significant. There is not much increase in lift, and the increase in stall angle of attack is also very limited. It can be said that this road is not working. A paper published in the February 1998 issue of the Journal of Beihang University: "Effect of Vortex Generators on Maximum Lift and Stall Angle of Attack of Wings" This article has commented in detail on the use of vortex generator lifting methods and points out the problems mentioned above. Therefore, we need to find other effective ways to increase. The fact that the vortex method has only a slight effect on the increase can be confirmed by a recent US patent 63186771 (November 2001). This document discloses the effect of using the "eagle-tip-nosed" vortex generator to raise the 172 wing. The data, curves and charts are given and compared. From the published results, it is obvious that the angle of attack and the lift coefficient of the stalled and unmounted garrule vortex generators have hardly changed. Only the stall characteristics have been slightly improved after the stall. Summary of the invention

The technical problem to be solved by the present invention is that the invention is to find a new way to address the shortcomings in the search for increasing methods, and proposes a new measure that is completely different from the currently used methods in order to obtain a large Good aerodynamic characteristics to improve lift and retard stall.

The technical solution adopted by the present invention to solve its technical problems is: The invention adopts a canopy wing, which adopts a sheet structure called a canopy wing, which is installed above the upper wing surface of the wing, and approaches without touching the upper wing. Face, as if a awning covered the upper surface of the wing. Because an airflow channel is formed between the wing and the upper surface of the wing, the airflow from the far front to the upper wing surface is restricted, so that the airflow above the faster wing surface is concentrated under the wing In the channel. Compared with the flow situation where no wing exists, the kinetic energy of the airflow flowing through the upper surface of the wing is greater, so that the airflow divergence point is moved to the rear greatly. As a result, the lift coefficient is increased (including the linear segment). On the other hand, the stall angle of attack is greatly increased, so that the maximum lift coefficient is increased, and the purpose of a substantial increase is achieved. It is worth noting that after the use of the wing, the original laminar flow was not converted into a turbulent surface layer, but the laminar flow was maintained. At the same time, the thickness of the canopy wing is small, so the resistance does not increase much, and the lift-drag ratio remains within a reasonable range. Because the canopy is just a thin wing with the same or similar curvature to the upper wing surface, the type resistance is very small, but the frictional resistance is increased. This is the only price, compared with a substantial increase in lift and stall angle of attack. This cost is worthwhile. The structure of the canopy wing requires great rigidity, and it is necessary to choose a suitable lightweight and rigid material. From the structural design, it can be considered that the canopy wing is made into an ultra-thin airfoil with a reinforcing rib and a streamlined shape. Fortunately, the force of the wing It is a force type of simply supported beam, which is beneficial to structural design and process manufacturing. In order to further increase the stall angle of attack, another oblique wing structure is proposed. This structure is aerodynamically different from the top-mounted monolithic canopy. However, it can also make the air flow separation point move backward greatly, and the increase of the stall angle of attack greatly exceeds the increase of the stall angle of attack of the combined wing of the top wing. BRIEF DESCRIPTION OF THE DRAWINGS

The working principle, structure and increasing effect of the present invention will be further described below with reference to the drawings.

FIG. 1 is a schematic diagram of an upper-mounted canopy wing installed on the wing.

Fig. 2 is a schematic diagram of an inclined canopy wing installed on the wing.

Figure 3 is a wind tunnel test curve using NACA23012 airfoil as the basic wing and fuselage combination. Fig. 4 is a schematic diagram of another embodiment in which the leading edge of the wing can be deflected downward.

Fig. 5 is a schematic diagram of the air flow along the wing section after the canopy wing is installed. Fig. 6 is a first embodiment of the present invention: an upper canopy aircraft. Fig. 7 is another embodiment of the present invention: an inclined canopy aircraft.

FIG. 8 is a schematic diagram of the relative positions of the canopy wing and the main wing of the present invention.

detailed description

As can be seen from FIG. 1: The canopy wing 1 is located above the upper wing surface 3 of the wing 2. The leading and trailing edges of the wing and the wing are parallel to each other along the wingspan, but along the chord direction, the distance between the lower surface of the wing and the upper surface of the wing is not necessarily equal. Is the relative height of the trailing edge of the wing and wing. ¾ is the relative height of the leading edge of the wing and the wing. When H _r =, the wing 1 and the upper surface 3 of the wing are parallel to each other. When ≠ ¾, the wing has a mounting angle Φ relative to the wing. The angle Φ is the angle between the line connecting the leading and trailing edges of the wing and the wing chord. The change in Φ (usually a positive value) is achieved by changing ¾ (fixed). The size of ¾ will affect the effect of increasing this device. Calculations, analysis and wind tunnel tests have shown that: The value must be carefully selected. It cannot be too small or too large. Too small, it may hinder the flow of air flow between the wing and the upper airfoil, and the lifting effect is not good. Too big will make the structure difficult. It will also reduce the efficiency fruit. It must be optimized experimentally to determine an optimal value. Preliminary wind tunnel tests have shown that the minimum value is approximately 10% of the wing aerodynamic chord length. Increasing the value, when the chord length is increased from 10% to 20%, the increase effect is obviously improved. It should be noted that the optimal value of the gap width is not fixed. The results obtained from wind tunnel tests are often larger because the scale effect and the thickness of the surface layer are related to the true dimensions of the aircraft. Better to be determined experimentally. As shown in FIG. 2, two pieces of canopy wings 5 and 6 are installed obliquely on the upper surface 3 of the wing 2. One end of each wing is connected to the upper surface of the wing. This connection can be a hinged connection or a fixed connection, depending on the situation. When the hinge connection is adopted, the curvature of the upper airfoil 3 must be taken into consideration, and the hinges 9 and 10 should ensure that the inclined wing 5 and 6 can be smoothly opened and retracted. One end of the inclined canopy wings 5 and 6 shown in FIG. 2 is connected to the upper wing surface of the wing 2, and the other end is separated from the upper wing surface by a certain distance. This distance determines the upper anti-angle Φ between the inclined wing and the wing. The size of Φ must also be optimized, too large and too small are not suitable. According to an embodiment of the present invention, wind tunnel tests have been performed in two cases: the upper inclination angle Φ = 10 ° and 20 °, and it is found that 20 ° is better than 10 °. When using the inclined wing, if it is used for low-speed aircraft, it can be fixed and not retracted. That is, the wing is opened during the entire flight. This approach greatly simplifies the structure. When used in supersonic aircraft, it should be designed as a retractable inclined wing. When it is not necessary to use the wing, the wing 5 and 6 should be retracted by using a hydraulic mechanism or other transmission device, and placed in the square grooves 7 and 8 in the wing, which fully fits the upper wing surface of the wing. Maintain a complete single wing profile.

FIG. 3 is a result of a wind tunnel test performed to compare the raising effect of the wing. It mainly shows the change of lift and stall angle of attack in three cases. The wind tunnel test model used is based on the NACA23012 airfoil, mounted on a cylindrical fuselage, and the fuselage head has an oval shape. The result given is the aerodynamic characteristics of a "wing-in-body" assembly. As can be seen from Figure 3, curve 12 is the change in the lift coefficient of the base structure 15 with the angle of attack, the stall angle of attack is about 12 °, and the maximum lift coefficient is about 0.94. Curve 13 is the lift characteristic curve of the "wing-one" combined body 16 after the upper-type canopy is installed. The stall angle of attack is approximately 20 °. The maximum lift coefficient is approximately 1.6. Curve 14 is the lift characteristic curve of the "wing-in-body" combination 17 after the inclined wing is installed. 4。 Stall angle of attack of 30 degrees or more (due to conditions, no test greater than 30 ° angle of attack.) The maximum lift coefficient is about 1.4. The interesting phenomenon is that in this form of inclined canopy wing, the lift characteristics are basically unchanged after installing the inclined canopy in a linear range smaller than the stall angle of attack. The above experimental results are limited to 1 / 2-2 Canopy wings on / 3 wingspan. (Note: Resistance and thrust moment characteristics Also unchanged. (Not shown in the figure) Compared with the existing lifting technology, the effect of increasing the maximum lift coefficient and the stall angle of attack of the present invention is greatly ahead. FIG. 4 shows another form of the upper wing: The front edge portion 18 of the wing can be deflected downward. This type of increase effect was tested in a wind tunnel test, and it was found that a downward deflection of 18 would increase the stall angle of attack to 25 °, but the maximum lift coefficient was slightly reduced. Figure 4 also shows that the trailing edge portion 23 of the wing flap can also be deflected downward. FIG. 5 shows a two-dimensional flow picture of the airfoil, with the airfoil 1 placed above the airfoil surface of the airfoil section 11. When the incoming flow V passes through the combination of the wing and the base wing, three flow fields are divided: Zone 1 is located below the lower airfoil of the basic airfoil, and its flow is basically the same as when the wing is not installed. Because the lower airfoil has less curvature and is flat, the air velocity is slower and the pressure is greater. Zone 3 is located between the upper surface of the base airfoil and the lower surface of the wing, forming a duct. Air flows into this area to be further accelerated. The accelerated airflow cannot pass through the wing to the outside, thus maintaining a relatively The large kinetic energy delays the separation of the airflow. Due to the high flow velocity, the pressure in zone 2 is lower than in zone 1. Zone 2 leads to the free flow field above the upper surface of the wing. Because the curvature of the wing is basically the same as the basic airfoil, but larger than the lower wing surface, the airflow is accelerated, and the pressure is relatively low. Because the wing is located between the two low-pressure zones 2 and 3, its force depends on The pressure difference between these two zones. We expect that the faster the flow speed in zone 3, the better and the pressure will become smaller. The airflow is also accelerated when it passes around the wing to Zone 2. It may be faster than Zone 3 and the pressure is very small. It can be inferred that the pressure difference between Zone 3 and Zone 2 is much smaller than Zone 1 and Zone 3. Therefore, the direct force of the wing will not be too great. This is good for structural design, and most of the increased lift actually acts on the base wing. Figure 6 is an embodiment of the upper canopy wing. The canopy wings 1 and 13 are placed above the upper wing surfaces of the left and right wings 2 and 14. 19 is the front support rod of the transmission device that pushes and retracts the wing. There can be several. Keep all front poles at the same height when pushing out. The height of the front support rod protruding from the upper airfoil is adjustable. 20 is similar to 19, it is the rear support. The installation angle of the canopy wing with respect to the wing can be achieved by adjusting the protruding height of the front support rod 19. Can be through the hydraulic mechanism or other means. 12 is any kind of aircraft, but also other transportation machinery in the atmosphere or water. Fig. 7 is an embodiment of the inclined wing. The canopy wings 5, 6, 15 and 16 are placed obliquely on the upper surface of the wing at an upside-down angle. The canopy wing can be stowed and stretched. The tilting canopy can be opened and retracted through a known transmission mechanism to push out or retract the actuator cylinder rod 21. It can also be used in current aircraft. The way of launching the hydraulic actuating mechanism of the spoiler is to realize the retracting of the inclined wing. When retracting, store the wing in the square grooves 7, 8, 17, and 22 on the surface of the wing, so that it fits perfectly with the upper surface of the wing, keeping the original First base airfoil profile.

The geometry of the wing and the relative position of the wing and the main wing are not limited to those shown in the implementation forces listed in the above description. In order to obtain the best aerodynamic effect, or to ensure the necessary strength and rigidity of the wing, or to reduce the weight, or due to the limitation caused by the deflection on the control surface of the main wing surface, in actual applications, the following situations will occur: From the perspective of a certain profile airfoil, the starting point of the leading edge of the canopy wing can be located at a position later than the leading edge of the aerodynamic chord of the main wing; . As shown in Figure 8. Among them, 23 is a wing on the wing. In addition, along the wingspan of the main engine, the wing of the larger aircraft can be divided into several shorter segments adjacent to each other. These fragments of the wing are coordinated and synchronized to be operated and retracted through electrical or mechanical connections between electrical, hydraulic, or mechanical mechanisms to replace the entire wing. This multi-structure form can be applied to parallel wing and inclined wing. The wing is not limited to the application on the main wing, but can also be applied to the normal or duck-type horizontal stabilizer or full-motion control surface.

The application of the canopy is not limited to the two embodiments described above. The invention may include many uses, not limited to various aircraft, may be a recovery device for spacecraft returning to the ground, may be a ground effect aircraft, or may be a machine moving in water or any other fluid. Utilizing the good high angle of attack characteristics of the inclined wing to design the anti-rotation device will greatly increase the safety of the aircraft.

Claims

Rights request

1. A canopy wing for increasing lift and stall angle of attack, comprising a wing, a laminar structure, and a retractable transmission mechanism, characterized in that the laminar structure called a canopy wing is located above the upper surface of the wing, The curvature of the wing and the curvature of the upper surface of the wing are the same or similar.

2. A canopy wing that increases lift and stall angle of attack according to claim 1, characterized in that-the sheet structure is placed above the upper surface of the wing to form an upper awning wing, which is driven by a hydraulic mechanism or any other transmission Mechanically connected to the wing.

3. The canopy wing for increasing lift and stall angle of attack according to claim 2, wherein the upper canopy wing can rotate around a trailing edge.

4. The canopy wing for increasing lift and stall angle of attack according to claim 2 or 3, characterized in that the distance from the rear edge of the upper canopy wing to the upper surface of the wing is fixed.

5. The canopy wing for increasing lift and stall angle of attack according to claim 2 or 3, characterized in that: the upper canopy wing can be retracted and placed in a square groove on the upper surface of the wing.

6. The canopy wing for increasing lift and stall angle of attack according to claim 1 or 2, characterized in that: the leading edge and the trailing edge of the wing are consistent with the positions of the leading edge and the trailing edge of the wing Or, the leading and trailing edges of the wing are sequentially arranged between the leading and trailing edges of the wing.

7. A canopy wing for increasing lift and stall angle of attack according to claim 1 or 2, characterized in that: an inclined angle between the inclined wing and the upper surface of the wing, and the inclined wing can Retract and place in a square groove on the upper surface of the wing.

8, according to claim one of the claims 1 to increase the lift and stall angle of attack of the wing canopy, _wherein: the upper wing surface of the sheet structure were connected to a mounting angle of the wing, the wing constituting the canted canopy The mounting angle is fixed during flight or can be adjusted.

9. A canopy wing for increasing lift and stall angle of attack according to claim 1 or 2 or 8, characterized in that: the leading edge portion and the trailing edge portion of the wing are deflected downward.

10. The canopy wing for increasing lift and stall angle of attack according to claim 1 or 2 or 8, characterized in that the canopy wing is composed of several segments, which are connected to each other through a hydraulic mechanism or other transmission mechanism to cooperate action.