CN115071939A - Follow-up symmetrical front wing sail - Google Patents

Abstract

The invention discloses a follow-up symmetrical flap sail, belonging to the field of ship and ocean engineering; the wing flap drive mechanism comprises a main sail assembly, wing flaps and a drive mechanism, wherein the two symmetrically arranged wing flaps are connected with the main sail assembly through the drive mechanism; the main sail assembly comprises a main sail and a main sail shaft, and the main sail is connected with the driving module in the ship body through the main sail shaft; the two planes of the chords of the main sail are symmetrical and are embedded in the grooves on the two sides of the main sail; the retraction and release actions of the two flaps are controlled through a transmission mechanism; when the corner of the main sail is 0, the two flaps are folded in the grooves on the two sides of the main sail to form an integral airfoil sail; when the main sail rotates, the flaps on one side are turned to the rear edge of the main sail in the same direction, and the flaps on the other side are retracted into the grooves of the main sail. The invention can push the flap backwards to increase the area of the sail, when the rotary flap of the main sail is pushed out, a gap is generated between the front edge of the flap and the main sail, so that a part of airflow can flow to the lee side of the sail through the gap on the windward side of the main sail to blow off the vortex on the rear edge, thereby greatly improving the lift force.

Description

A follow-up symmetrical flap sail

technical field

The invention belongs to the field of ships and marine engineering, and particularly relates to a follow-up symmetrical flap sail.

Background technique

Due to the rise in fuel prices in recent years and the strict requirements of the International Maritime Organization for ship energy conservation and emission reduction, major international shipping companies are actively looking for new methods for ship energy conservation and emission reduction, and have increased their efforts in new energy development. put in. Wind energy, as a clean natural energy, has been favored by people. Therefore, as an application of ship navigation aids, sail has become a research hotspot in the shipping industry all over the world. On the other hand, due to the characteristics of low energy consumption and ultra-long voyage, unmanned sailboats have also been favored in the field of maritime unmanned systems in various countries in recent years. The sail works by using the pressure difference created by the airflow around the sail to generate lift, which in turn generates power. As a result, the higher the efficiency of the sail for the same area, the lower the energy consumption of the ship and the lower the emissions.

Sails can be divided into soft sails and wing sails (ie rigid airfoil sails). Because wing sails are relatively simple to operate and can provide relatively large lift, they are widely used in unmanned sailboats and large ship navigation aids. The current focus of research in this field is to change the structure of the sail to increase the lift of the sail, one of which is to add flaps to the end of the sail. Most flap sails now use simple flaps or slotted flaps. Simple flap structure is simple, easy to install and operate, but this structure basically does not change the area of the sail, so the increase in lift is small; the slit flap has a more obvious increase in lift, but according to the current design, this kind of flap The asymmetry between the left and right when unfolding makes the aerodynamic performance of the sail inconsistent when turning to both sides, which is not conducive to control (such as a new type of high-lift sail with movable flaps proposed by Denmark's Rosander M and Bloch JOV in 2000). Furthermore, the design of the slotted flaps places a large number of flap slider mechanisms on the outside of the sail, and external disturbances will reduce the reliability of such mechanisms (see Patent Grant Publication No. CN104925241B).

SUMMARY OF THE INVENTION

Technical problem to be solved:

In order to avoid the deficiencies of the prior art, the present invention provides a follow-up symmetrical flap sail based on the structural characteristics of the Fuller flap. The mechanical non-power transmission mechanism realizes the retracting and retracting action of the flaps. When the wing sail is turned, the flap is released, which increases the surface area and profile camber of the sail, and greatly increases the lift of the sail; and since the Fuller flap is a retreating flap, the airflow blows away the trailing edge vortex through the gap, so that the lift effect is very high. obvious.

The technical scheme of the present invention is: a follow-up symmetrical flap sail, comprising a main sail assembly, a flap and a transmission mechanism, and the two symmetrically arranged flaps are connected with the main sail assembly through the transmission mechanism;

The mainsail assembly includes a mainsail and a mainsail shaft, the mainsail is connected to a driving module in the hull through the mainsail shaft, and the rotation of the mainsail is controlled by the driving module;

The two flaps are symmetrical to the plane where the chord of the main sail is located, and are embedded in the grooves on both sides of the main sail;

The retracting and retracting actions of the two flaps are controlled by the transmission mechanism; when the main sail angle is 0, the two flaps are retracted into the grooves on both sides of the main sail to form an integral airfoil sail; when the main sail rotates, a The side flaps are turned in the same direction at the trailing edge of the mainsail, and the other flaps are retracted into the mainsail grooves.

A further technical solution of the present invention is: the drive module is a motor, the output shaft of the motor is coaxially connected with the main sail shaft, and the motor controls the rotation of the main sail shaft.

A further technical solution of the present invention is: the transmission mechanism comprises a main sail shaft gear, a transmission shaft bottom gear, a transmission shaft main gear, a transmission shaft, a double gear, a rack, and a push rod assembly;

The main sail is provided with a through hole in the spanning direction, and the through hole is located near the leading edge of the main sail; the transmission shaft is arranged in the through hole and can rotate relatively due to clearance fit;

The transmission shaft bottom gear is fixed on the bottom end of the transmission shaft and meshes with the main sail shaft gear fixed on the main sail shaft; the power of the drive module is transmitted to the transmission shaft through gear transmission;

The main gear of the transmission shaft, the double gear and the rack are located in the main sail, the main gear of the transmission shaft is coaxially sleeved on the transmission shaft, the two racks are arranged side by side, and the tooth surfaces face both sides; the two double gears are mutually Upside down, the pinion ends are meshed with the main gear of the transmission shaft, and the large gear ends are meshed with two racks respectively;

Guide holes are respectively opened between the rack and the grooves on both sides of the main sail, and the flaps on both sides are respectively connected with the rack through push rod assemblies passing through the guide holes; The coupling gear rotates, which in turn drives the rack and push rod assembly to control the retraction and release of the flaps.

A further technical solution of the present invention is: the push rod assembly includes an intermediate push rod and a secondary power push rod, one end of the intermediate push rod is hinged with the rack, and the other end is hinged with the fixed end of the secondary power push rod; The free end of the secondary power push rod is hinged with the leading edge of the flap.

A further technical solution of the present invention is that: the secondary power push rod is a telescopic structure, and a spring limiting structure is arranged therein.

A further technical solution of the present invention is that the two ends of the transmission shaft are respectively installed with fixed plates to limit the axial displacement thereof.

A further technical solution of the present invention is that the section of the flap is a variable-curvature airfoil surface.

The further technical scheme of the present invention is: the groove profile of the main sail is consistent with the front end of the variable curvature airfoil profile of the flap, so as to ensure that the retracted flap is completely fitted in the groove of the main sail;

The front end of the groove of the main sail has a rounded structure, so that the airflow will not generate turbulent flow when passing through, and can smoothly flow to the flaps.

The further technical scheme of the present invention is: the upper and lower ends of the flaps are respectively connected to the upper and lower groove walls in the groove of the main sail through the mainsail fixed tertiary sliding rods respectively; the mainsail fixed tertiary sliding rods are telescopic rods, The fixed end is rotatably connected with the groove wall, and the free end is rotatably connected with the end face of the flap; when the flap is controlled and retracted by the transmission mechanism, the fixed three-stage sliding rod of the main sail located at the upper and lower ends of the flap ensures the movement of the flap through the telescopic movement. trajectory.

A further technical solution of the present invention is that the main gear of the transmission shaft of the transmission mechanism is located in the middle position of the main sail in the span direction, and the three-stage sliding rod is fixed in combination with the main sail at the upper and lower ends, so as to realize the smooth retractable and retractable action of the flap.

A further technical solution of the present invention is: the fixed end of the secondary power push rod is located in front of the fixed end of the mainsail fixed tertiary sliding rod, and is closer to the leading edge of the main sail and the chord;

The included angle between the extension line of the secondary power push rod and the chord of the main sail is θ ₁ , so that when the flap is pushed out, a gap is formed between its leading edge and the inner side of the other flap, and the airflow blows away the trailing edge vortex through the gap to increase. Lift effect; the angle between the mainsail fixed tertiary sliding rod and the main sail chord is θ ₂ , θ ₂ > θ ₁ , so that the lateral movement distance of the trailing edge of the flap is greater than that of the leading edge, and the longer the push-out distance, the higher the rotation angle. the larger the effect.

How it works: When the sail is turned, the larger the turning angle, the greater the lift generated, the flap will turn in the same direction towards the trailing edge of the sail, and the other flap will retract to a fixed position. The turning angle of the flaps on the turning side has a linear relationship with the sail position angle turned by the main sail. big. When the sail position angle is zero, the flaps on both sides are retracted, and the shape is a complete wing sail, and the lift generated at this time is the smallest. The angle and length of the flaps are the same when the wing sail is turned to both sides, which ensures that the lift generated when the sail is turned to both sides is the same under the same conditions, thereby solving the problem of the flap sail turning to both sides in the prior art. Inconsistent aerodynamics. The control part of the present invention is purely mechanical design, there is no motor and hydraulic device inside the sail, and the power of the mainsail and flaps only depends on the force of the hull to turn the mainsail. Except for the central shaft gear, there are no other exposed mechanical structures. When the sail angle is zero, all the mechanical structures are inside the main sail, which avoids the contact between the core transmission mechanism and the outside world, and reduces the interference of the environment on the mechanism.

beneficial effect

The beneficial effects of the present invention are:

1. The flap sail designed by the present invention can not only push the flaps backward to increase the area of the sail, but also install a transmission mechanism and a series of push rods with a predetermined angle in the main body of the existing wing sail. , When the flap is pushed out, due to the included angle between the power push rod and the main sail chord, while the flap is retreating and turning, a gap can be created between the leading edge of the flap and the main sail, so that part of the airflow can be The trailing edge vortex is blown away by the windward side of the mainsail passing through this gap to the leeward side of the sail, which can greatly improve the lift. This flapsail design, which combines the retracted flap and the slotted flap, achieves the effect of increasing the sail area, increasing the camber, and controlling the boundary layer, that is, the effect of the Fuller flap. Referring to Figure 1, under the same angle of rotation, the lift effect of the Fuller flap sail is better than that of the simple flap sail. Under the same energy conditions, this design can effectively increase the range of the aircraft.

2. Most of the slotted flap sails and the retreating flap sails are not symmetrical now, but the present invention can make the aerodynamic characteristics consistent when the sails are rotated to both sides, and it is easy to control when the main sail is rotated to the same angle to both sides. When the power push rods on both sides push out the flaps on both sides, the distance that the flaps deviate from the fore and aft lines of the main sail, and the angle that the flaps turn outward are all the same, resulting in the increased area of the sail, the increased camber of the profile and the opening of the seam are the same size. Obviously, under the same angle of attack and air conditions, the aerodynamic characteristics of such a design are the same when the sail turns the same angle on both sides, and the lift generated is also the same. This symmetrical feature is that both sides of the sail have the same and complete aerodynamic characteristics, which eliminates the turbulent flow generated when the asymmetrical flaps are turned to the side of the incomplete aerodynamic characteristics, improves the efficiency of the sail, and saves more energy. And compared with the design in which the asymmetric sail rotates and receives unbalanced forces on both sides, the present invention reduces the difficulty of controlling the sail. It improves the maneuverability of the ship, reduces the energy consumption of the asymmetric flap sail due to this part of the maneuver, and further saves energy. This also reduces the complexity of the control system, thereby increasing the robustness of the system.

3. The present invention can control the degree of flaps to be pushed out in direct proportion to the turning angle of the main sail. The larger the sail angle, the greater the lift provided. When the sail angle is zero, the two flaps are fully retracted, and no excess is generated. , Unwanted resistance. Compared with the traditional sail, the invention has higher lift coefficient and lift-drag ratio, and is easy to realize variable angle control. The flaps can be turned up to a maximum angle of 30°, making lift greater than drag.

4. In the present invention, the flap rotation angle and the push-out area can change with the angle that the sail turns, which solves the problem that in some designs, the flap only has two modes of unfolding and retracting. The lift coefficient and lift-drag ratio increase, and the thrust coefficient of the sailboat increases, which has a better impact on the performance of the sailboat.

5. The structure of the present invention is simple. The core transmission mechanism inside the main sail has only three gears, two racks and two sets of push rods, no additional motor or hydraulic device is needed to provide thrust, and the main mechanisms are all inside the main sail, making the system It is more simple and reliable, and it is not easy to be disturbed by external factors. When unfolded, the force-bearing area of the sail can be increased, which greatly improves the utilization rate of wind energy. It is beneficial to the stability of the ship, and at the same time, it is convenient for maintenance and repair. Using wind energy to sail, greatly extending its working time.

Description of drawings

Figure 1 is a comparison diagram of the lift coefficient curve;

FIG. 2 is an overall isometric view of a follow-up symmetrical flap sail based on the Fuller flap structure of the present invention when both flaps are retracted.

Figure 3 is the overall isometric view when the left flap is pushed out;

Figure 4 is a front view when the flaps on both sides of the flap sail are retracted;

Figure 5 is a front view when the left flap of the flap sail is pushed out;

Figure 6 is a top view when the flaps on both sides of the flap sail are retracted;

Figure 7 is a top view when the flaps on both sides of the flap sail are retracted;

Figure 8 is a schematic diagram of the connection between the internal transmission mechanism of the mainsail and the flaps. The transmission mechanism is connected to the flaps, and the mainsail fixed three-stage sliding rod is also connected to the flaps. This is the state when both flaps are retracted;

Figure 9 is a schematic diagram of the connection between the internal transmission mechanism of the mainsail and the flaps. The transmission mechanism is connected to the flaps, and the mainsail fixed three-stage sliding rod is also connected to the flaps. This is the state when the left flap is pushed out;

Fig. 10 is a partial enlarged view of Fig. 7, highlighting the meshing and connection of the main gear of the transmission shaft with the double gear, rack, intermediate push rod and power push rod;

Fig. 11 is a partial enlarged view of Fig. 8, which highlights the meshing and connection of the main gear of the transmission shaft with the double gear, rack, intermediate push rod, and power push rod;

Figure 12 is a schematic diagram of the appearance of the upper left side of the trailing edge of the sail when the flaps on both sides are retracted;

Figure 13 is a schematic perspective view of the connection between the fixed third-stage sliding rod and the flaps of the main sail above the left side of the trailing edge of the sail when the flaps on both sides are retracted;

Figure 14 is a schematic diagram of the appearance of the upper left side of the trailing edge of the sail when the left flap is pushed out;

Figure 15 is a schematic perspective view of the connection between the mainsail fixed tertiary sliding rod and the flap on the upper left side of the trailing edge of the sail when the left flap is pushed out;

Figure 16 is a partial enlarged schematic view of the connection between the power push rod and the left flap when the left flap is pushed out;

Description of reference numerals: 1-mainsail; 2-mainsail shaft; 3-mainsail shaft gear; 4-mainsail fixed three-stage sliding rod; 5-flaps; 6-flaps shaft 7-flaps leading edge fixed pin; 8- drive shaft bottom gear; 9- drive shaft main gear; 10- double gear; 11- rack; 12- rack track restraint; 13- intermediate push rod; 14- secondary power push rod; 15 -Fixed piece; 16-Transmission shaft.

Detailed ways

The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention and should not be construed as limiting the present invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " rear, left, right, vertical, horizontal, top, bottom, inside, outside, clockwise, counterclockwise, etc., or The positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, Therefore, it should not be construed as a limitation of the present invention.

Referring to Figure 2, Figure 3, Figure 4 and Figure 5, a follow-up symmetrical flap sail in this embodiment is composed of a main sail assembly, flaps and a transmission mechanism. The two symmetrically arranged flaps 5 are connected with the main sail assembly through a transmission mechanism; the main sail assembly includes a main sail 1 and a main sail shaft 3, and the main sail 1 is connected with the drive module in the hull through the main sail shaft 2, and the drive module Control the rotation of the main sail; the two described flaps are symmetrical with the plane where the chord of the main sail 1 is located, and are embedded in the grooves on both sides of the main sail 1;

The retracting and retracting actions of the two flaps are controlled by the transmission mechanism; when the main sail angle is 0, the two flaps are retracted into the grooves on both sides of the main sail to form an integral airfoil sail; when the main sail rotates, a The side flaps are turned in the same direction at the trailing edge of the mainsail, and the other flaps are retracted into the mainsail grooves.

The section of the main sail 1 is NACA0415 airfoil, which can ensure that the lift force is greater than the drag force under the conventional aerodynamic characteristics. The groove on the trailing edge of the main sail 1 is a variable curvature concave arc surface concave to the midline of the main sail, and the front side of the flap 5 is a variable curvature airfoil surface with the same curvature as the variable curvature concave arc surface on the main sail. In the retracted state, the flap 5 closely fits the variable curvature concave arc surface on the main sail 1 through its variable curvature airfoil surface. The front end of the slot is curved, so that the airflow will not generate turbulence when passing through, and it can flow smoothly to the flaps.

The transmission mechanism includes a main sail shaft gear 3, a transmission shaft bottom gear 8, a transmission shaft main gear 9, a transmission shaft 16, a double gear 10, a rack 11, and a push rod assembly; The through hole is located near the leading edge of the main sail 1; the transmission shaft 16 is arranged in the through hole, and can rotate relative to the clearance fit, and the upper and lower ends are respectively installed with fixed plates to limit its axial displacement. The transmission shaft bottom gear 8 is fixed on the bottom end of the transmission shaft 16 and meshes with the main sail shaft gear 3 fixed on the main sail shaft 2; the power of the drive module is transmitted to the transmission shaft 16 through gear transmission; the transmission shaft The main gear 9, the double gear 10, and the rack 11 are located in the main sail 1. The main gear 9 of the transmission shaft is coaxially sleeved on the transmission shaft 16. The two racks 11 are arranged side by side with the tooth surfaces facing both sides. The track restraint 12 limits its offset to ensure the movement track; the two double gears 10 are inverted to each other, the pinion ends of which are meshed with the main gear of the transmission shaft, and the large gear ends are respectively meshed with two racks; the racks 11 and Guide holes are respectively opened between the grooves on both sides of the main sail 1, and the flaps 5 on both sides are respectively connected with the rack 11 through the push rod assembly passing through the guide holes; the drive shaft 16 drives the drive shaft main gear 9, double The coupling gear 10 rotates, thereby driving the rack 11 and the push rod assembly to control the retraction and release of the flaps.

The middle part of the flap 5 is connected with the main sail 1 through a push rod assembly, the push rod assembly includes an intermediate push rod 13 and a secondary power push rod 14, and one end of the intermediate push rod 13 is hinged to the rack 11 , and the other end is hinged with the fixed end of the secondary power push rod 14 ; the free end of the secondary power push rod 14 is hinged with the front edge of the flap 5 . The movement of the flaps 5 is mainly powered by the secondary power push rod 14 .

The upper and lower ends of the flaps 5 are respectively slidably connected to the upper and lower groove walls in the groove of the main sail 1 through the main sail fixed three-stage slide rod 4; the main sail fixed three-stage slide rod 4 is a telescopic rod, and its fixed end is The groove wall is rotatably connected, and the free end is rotatably connected with the protruding shaft provided on the end face of the flap 5 through the bearing; when the flap 5 is controlled and retracted by the transmission mechanism, the main sail at the upper and lower ends of the flap 5 is fixed to the third-stage sliding rod 4 by telescopic The movement guarantees the trajectory of the movement of the flaps.

Referring to Fig. 6, Fig. 7, and Fig. 12-Fig. 16, when the flaps 5 on both sides are retracted to the main sail 1, the sectional view is a complete, ordinary airfoil sail, and the resistance of the entire sail is the smallest at this time. . When the main sail 1 turns a certain angle, the flaps 5 will be pushed out accordingly. Since the present embodiment is based on the structure of the retracted flap such as the Fuller flap, from the sectional view, when the flap 5 is pushed out backward, the main sail is fixed between the tertiary sliding rod 4 and the head and tail lines of the main sail 1. The angle is greater than the included angle between the secondary power push rod 14 and the head and tail lines of the main sail 1, and the connection point between the secondary power push rod 14 and the flap 5 is located in front of the main sail fixed tertiary sliding rod 4 and the flap 5. The trailing edge of the flap 5 will move away from the bow and tail lines of the main sail 1, which not only increases the air flow area, but also increases the camber of the profile, thereby increasing the area of the negative pressure area on the other side of the main sail 1. Moreover, a gap will be generated between the flap 5 that is pushed out and the flap 5 that is not pushed out on the other side, so that the airflow blows away the trailing edge vortex through the gap to increase the lift effect.

Referring to Figures 8 to 11, it shows the connection of the transmission mechanism with the flaps 5, when the two flaps retract the main sail 1, and the one side flaps 5 are pushed out. The driving mechanism includes a transmission shaft 16 , two double gears 10 , two racks 11 , two intermediate push rods 13 , and two secondary power push rods 14 . The center of the transmission shaft 16 is fixed with a main gear 9 of the transmission shaft, which meshes with a double gear 10 which is reversed to each other at the backward positions on both sides of the transmission shaft. The double gear 10 is that the pinion meshes with the main gear 9 of the transmission shaft, and the large gear meshes with the rack 11 . The large gears of the two double gears 10 are staggered and arranged one by one, leaving space for the rack 11 . A section of the rack track restraint 12 is sleeved on the transmission shaft 16, and a section is arranged with two bearings, which are used to constrain the rack 11 to only move horizontally back and forth. The end of the rack 11 pointing to the trailing edge of the main sail has a fixed pin with a bearing sleeve connected to the intermediate push rod 13, the intermediate push rod 13 is connected with the secondary power push rod 14, and the secondary power push rod 14 passes through the main sail. The fixing hole is connected with the flap 5. A spring is installed between the inner and outer layers of the secondary power pushrod 14 , and if it is pulled, it will be forced to fix the flap 5 in the slot at the rear end of the main sail 1 . When the main sail 1 rotates, for example, when the sail turns to the right, the main sail shaft gear 3 rotates clockwise, which drives the transmission shaft bottom gear 9 to rotate counterclockwise, so that the transmission shaft main gear 8 also moves counterclockwise, thereby driving the double gear 10 Rotate clockwise, so that the right rack 11 pushes out the right flap 5 backward, the greater the angle of sail rotation, the more the flap 5 is pushed out; the left rack 11 moves forward, due to the secondary power push rod 14 There is a spring in the middle, so that when the push rod moves forward of the main sail 1, the flap 5 can be pulled and fixed in the groove on the trailing edge of the main sail 1.

From the sectional view of the flaps, the fixed point of the secondary power push rod is in front of the mainsail fixed tertiary sliding rod, and it is closer to the fore and aft lines of the main sail. There is a small angle between the extension line of the secondary power push rod and the fore and aft lines of the main sail, so that when the flap is pushed out, a gap is created between the leading edge and the inner side of the other flap, and the airflow blows away the trailing edge vortex through the gap to increase the lift. Effect. The angle between the mainsail fixed pushrod and the main sail fore and aft line is slightly larger than the power pushrod, so that the lateral movement distance of the trailing edge of the flap is greater than that of the leading edge, and the longer the push-out distance, the larger the turning angle. For example, in the design of the present invention, the included angle of the power push rod is 5°, the included angle of the main sail fixed push rod is 10°, and the action points of the two sets of rods on the section of the flap form a moment. For example, when the left flap is pushed out, the two action points form a clockwise moment, and the flap will rotate outward at a certain angle with the action point of the push rod as the axis. This angle is linearly related to the distance that the power push rod is pushed out, and the final effect is that the greater the angle of the mainsail rotation, the greater the angle of the flap rotation. Since the resistance will be greater than the lift force when the flaps are turned out at an excessively large angle, the maximum out-turn angle of the flaps designed in the present invention during modeling is 30°.

Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and those of ordinary skill in the art will not depart from the principles and spirit of the present invention Variations, modifications, substitutions, and alterations to the above-described embodiments are possible within the scope of the present invention without departing from the scope of the present invention.

Claims (10)

1. A follow-up symmetrical flapped sail is characterized in that: the wing flap drive mechanism comprises a main sail assembly, wing flaps and a drive mechanism, wherein the two symmetrically arranged wing flaps are connected with the main sail assembly through the drive mechanism;

the main sail assembly comprises a main sail and a main sail shaft, the main sail is connected with a driving module in the ship body through the main sail shaft, and the driving module is used for controlling the rotation of the main sail;

the two flaps are symmetrical with the plane where the chord of the main sail is located and embedded in the grooves on the two sides of the main sail;

the retraction and release actions of the two flaps are controlled through the transmission mechanism; when the corner of the main sail is 0, the two flaps are folded in the grooves on the two sides of the main sail to form an integral airfoil sail; when the main sail rotates, the flaps on one side are turned to the rear edge of the main sail in the same direction, and the flaps on the other side are retracted into the grooves of the main sail.

2. The follow-up symmetric flap sail of claim 1, wherein: the transmission mechanism comprises a main sail shaft gear, a transmission shaft bottom gear, a transmission shaft main gear, a transmission shaft, a duplicate gear, a rack and a push rod assembly;

the main sail is provided with a through hole along the unfolding direction, and the through hole is positioned at the position, close to the front edge, of the main sail; the transmission shaft is arranged in the through hole and can rotate relatively in clearance fit;

the transmission shaft bottom gear is fixed at the bottom end of the transmission shaft and is meshed with a main sail shaft gear fixed on a main sail shaft; transmitting power of the driving module to the transmission shaft through gear transmission;

the transmission shaft main gear, the duplicate gear and the racks are positioned in the main sail, the transmission shaft main gear is coaxially sleeved on the transmission shaft, and the two racks are arranged in parallel and have tooth surfaces facing to two sides; the two duplicate gears are inverted, the small gear ends of the duplicate gears are meshed with the main gear of the transmission shaft, and the big gear ends of the duplicate gears are respectively meshed with the two racks;

guide holes are respectively formed between the rack and the grooves on the two sides of the main sail, and the flaps on the two sides are respectively connected with the rack through push rod assemblies penetrating through the guide holes; the transmission shaft drives the transmission shaft main gear and the duplicate gear to rotate, and further drives the rack and the push rod assembly to control the retraction of the flap.

3. The follow-up symmetric flap sail of claim 2, wherein: the push rod assembly comprises a middle push rod and a secondary power push rod, one end of the middle push rod is hinged with the rack, and the other end of the middle push rod is hinged with the fixed end of the secondary power push rod; the free end of the secondary power push rod is hinged with the flap leading edge.

4. The follow-up symmetric flap sail of claim 3, wherein: the secondary power push rod is of a telescopic structure, and a spring limiting structure is arranged in the secondary power push rod.

5. The follow-up symmetric flap sail of claim 2, wherein: the both ends of transmission shaft are installed the stationary blade respectively for limit its axial displacement.

6. The follow-up symmetric flap sail of claim 1, wherein: the cross section of the flap is a variable curvature airfoil surface.

7. The follow-up symmetric flap sail of claim 6, wherein: the groove profile of the main sail is consistent with the front end of the wing flap variable-curvature airfoil profile, so that the retracted wing flap is completely attached to the groove of the main sail;

the front end of the groove of the main sail is of a fillet structure, so that airflow can not generate turbulent flow when passing through and can smoothly flow to the flap.

8. The follow-up symmetric flapped sail according to any one of claims 1 to 7, wherein: the upper end and the lower end of the flap are respectively connected with the upper groove wall and the lower groove wall in the main sail groove in a sliding manner through a main sail fixing three-stage sliding rod; the three-stage sliding rod for fixing the main sail is a telescopic rod, the fixed end of the telescopic rod is rotatably connected with the wall of the slot, and the free end of the telescopic rod is rotatably connected with the end face of the flap; when the flap is controlled to be retracted and extended by the transmission mechanism, the three-level sliding rods fixed on the main sails at the upper end and the lower end of the flap ensure the motion track of the flap through telescopic motion.

9. The follow-up symmetric flap sail of claim 8, wherein: a main gear of a transmission shaft of the transmission mechanism is positioned in the middle of the main sail in the unfolding direction, and three-stage sliding rods are fixed in combination with the main sails at the upper end and the lower end, so that the stable folding and unfolding action of the flap is realized.

10. The follow-up symmetrical flap sail according to claim 8 or 9, wherein: the fixed end of the secondary power push rod is positioned in front of the fixed end of the fixed tertiary sliding rod of the main sail and is closer to the front edge and the chord of the main sail;

the included angle between the extension line of the secondary power push rod and the chord of the main sail is theta ₁ When the flap is pushed out, a gap is generated between the leading edge of the flap and the inner side of the flap on the other side, and airflow blows away vortex at the trailing edge through the gap to increase the lift effect; the included angle between the three-level sliding rod fixed to the main sail and the wing chord of the main sail is theta ₂ ，θ ₂ ＞θ ₁ And the transverse moving distance of the trailing edge of the flap is larger than that of the leading edge, so that the effect that the pushing-out distance is longer and the rotating angle is larger is achieved.

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