Unmanned aerial vehicle foldable empennage with optimized aerodynamic performance
By designing an inverted U-shaped twin vertical tail structure and a foldable tail fin with the symmetrical airfoil of the NACA 9000, the problems of redundant and non-foldable tail fin structures of fixed-wing UAVs were solved, improving aerodynamic performance and portability, and ensuring flight stability and safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-27
- Publication Date
- 2026-03-06
AI Technical Summary
The redundant tail structure of existing fixed-wing UAVs results in poor aerodynamic performance, and the non-foldable design occupies a lot of space during transportation and storage, posing a risk of damage. Furthermore, the detachable solution suffers severe wear on the connecting parts, affecting the aerodynamic shape accuracy and safety.
The foldable tail fin adopts an inverted U-shaped twin vertical tail structure, combined with the NACA 9000 symmetrical airfoil and hexahedral frame structure. The tail fin can be quickly deployed and folded through connecting rods and folding components. Locking components ensure connection reliability, avoid turbulence interference, and improve aerodynamic efficiency and stability.
It achieves efficient folding and unfolding of the tail fin, reduces storage space requirements, improves aerodynamic performance and flight stability, reduces structural wear risk, and enhances portability and safety.
Smart Images
Figure CN223972760U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of unmanned aerial vehicle (UAV) technology, and more specifically to a foldable tail fin for UAVs with optimized aerodynamic performance. Background Technology
[0002] Unmanned aerial vehicles (UAVs), or drones for short, are unmanned aircraft controlled by radio remote control equipment and their own program control devices. Fixed-wing UAVs generate lift through the relative motion of their wings and the airflow, giving them an inherent advantage in aerodynamic efficiency. Therefore, they exhibit characteristics such as long range, high speed, and large payload in practical applications, making them widely used in fields such as inspection, positioning, and aerial photography. With the rapid development of UAV technology, the functions of fixed-wing UAVs are becoming increasingly sophisticated, and their functional completeness and mission adaptability are constantly improving. It is worth noting that in recent years, the application scenarios for UAVs have been rapidly evolving towards greater complexity and diversification, placing more stringent demands on the environmental adaptability of these aircraft.
[0003] From a structural design perspective, fixed-wing UAVs typically employ a rigid, blended-wing-body architecture to achieve both high strength and efficiency, but this inevitably leads to structural redundancy. UAVs are extremely sensitive to weight parameters; every 1% increase in structural weight results in a 3%-5% reduction in range. Despite this, existing fixed-wing UAVs generally suffer from a significant contradiction between payload capacity and weight specifications. Most fixed-wing UAVs use an integrated tail fin and fuselage design without a folding mechanism, resulting in an excessively large storage volume when not in operation and increasing the risk of wing damage during transport. Although some research has attempted to use detachable tail fin solutions, repeated disassembly and reassembly cause wear on the connecting parts, significantly reducing aerodynamic accuracy and posing a safety hazard of structural loosening during flight. Utility Model Content
[0004] This invention provides a foldable tail fin for UAVs with optimized aerodynamic performance, overcoming the problems of redundant tail fin structures and poor aerodynamics caused by detachable designs in existing fixed-wing UAVs. This tail fin can avoid interference from the downwash turbulence of the main wing, reduce vibration, and is foldable, which facilitates quick folding and efficient use of space, thereby enhancing the portability and efficiency of fixed-wing UAVs.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: a foldable tail fin for an unmanned aerial vehicle (UAV) with optimized aerodynamic performance, comprising a tail fin frame, wherein the tail fin frame is an inverted U-shaped double vertical tail structure, including a horizontal tail stabilizer and two vertical tail stabilizers on both sides, the vertical tail stabilizers being perpendicularly connected to the horizontal tail stabilizers, and elevators and rudders being respectively installed on the vertical tail stabilizers and the horizontal tail stabilizers, the tail fin frame being connected to a connecting rod, the end of the connecting rod being connected to a folding component that cooperates with the fuselage, the folding component being hinged to the fuselage and provided with a locking component, thereby realizing the flipping and folding of the tail fin.
[0006] Furthermore, the horizontal stabilizer includes a leading edge, a spar, and a trailing edge arranged in parallel to each other, and a number of ribs are provided inside the tail fin frame, with the ribs spaced apart and spanning between the leading edge, the spar, and the trailing edge.
[0007] Furthermore, the wing rib includes a first reinforcing wing rib and a second reinforcing wing rib, which are symmetrically installed in the middle of the tail wing frame. The first reinforcing wing rib has a servo mounting hole, in which a horizontal tail servo connected to the elevator is installed. The wing rib also includes two ordinary wing ribs, which are respectively installed on both sides of the first reinforcing wing rib and the second reinforcing wing rib.
[0008] Furthermore, the rib is a symmetrical airfoil with a hollow center. The ordinary rib adopts a NACA 9000 symmetrical airfoil with a thinner leading edge and a relative thickness of 9.00%, with a hollow center, passing through the wing spars, with the front end (fish mouth) fitting with the leading edge and the rear end fitting with the trailing edge.
[0009] Furthermore, a plurality of tail fin baffles are provided between the first reinforcing wing rib and the second reinforcing wing rib, and the connecting rod is connected to the tail fin baffles.
[0010] Furthermore, the tail fin mount also includes a servo housing, which is installed inside the vertical tail stabilizer and is used to install a servo for controlling the rudder. The upper surface of the servo housing is curved and has the same curvature as the airfoil.
[0011] Furthermore, the wing spars include symmetrically arranged upper and lower spars, with a web plate provided on the side between the upper and lower spars. The web plate bears and transmits the wing shear force, and both the wing plate and the web plate are symmetrically hollowed out.
[0012] Furthermore, the folding component adopts a hexahedral frame structure, including a lower plate and an upper plate. A side plate and a fixed baffle are disposed between the upper and lower plates. The fixed baffle has mounting holes for installing the connecting rod. The folding component is assembled from the upper plate, lower plate, side plate, and fixed baffle to form a hexahedral frame structure. The two fixed baffles are at a certain angle to the horizontal plane and connected to the side plate of the folding component. The connecting rod is fixed by adhesive bonding, thereby effectively raising the installation position of the tail fin.
[0013] Furthermore, the locking component adopts a latch, the upper plate of the folding component has a latch mounting hole for latch installation, and the lower plate of the folding component is hinged to the body with a hinge, and the lower plate has a hinge mounting hole for hinge installation. The foldable connection with the body is achieved through the hinge and latch.
[0014] Furthermore, the connecting rod is set at an angle to the horizontal direction. The fixing baffle of the folding component and the tail fin baffle on the tail fin frame are both set at a certain angle to the horizontal direction, raising the tail fin mounting position and avoiding turbulence interference.
[0015] In summary, compared with the prior art, this utility model has the following beneficial effects:
[0016] 1. High-efficiency airfoil design: This invention selects the NACA 9000 symmetrical airfoil with a thinner leading edge and a relative thickness of 9.00% as the tail airfoil. This provides good two-way maneuverability without increasing structural complexity, adapting to changes in lift in both positive and negative directions. Simultaneously, this airfoil has low pressure drag and friction drag, which helps improve the aerodynamic efficiency and control response speed of the tail fin.
[0017] 2. Foldable tail fin enhances portability and adaptability: The tail fin is connected to the folding mechanism via a connecting rod, enabling rapid deployment and folding. Before flight, the tail fin can be deployed from under the fuselage and reliably connected to the fuselage via a latch on the folding mechanism; after flight, simply unlatch the latch to fold the tail fin back under the fuselage. This design not only effectively saves storage and transportation space but also enhances the aerodynamic consistency and service life of the tail fin structure.
[0018] 3. Adopting an inverted U-shaped tail structure to optimize aerodynamic characteristics: This invention, combined with overall aircraft aerodynamic analysis, adopts an inverted U-shaped tail structure. This structure can significantly reduce airflow interference at the tail and increase the longitudinal lever arm length, thereby improving flight stability and control sensitivity. It also exhibits an endplate effect, further enhancing tail efficiency.
[0019] 4. Raise the tail fin installation position to avoid turbulence interference: By appropriately raising the tail fin, the horizontal tail fin avoids the turbulence area generated by the downwash of the main wing, significantly reducing tail fin flutter and improving the stability and control accuracy of the tail fin in various flight attitudes. Attached Figure Description
[0020] Figure 1 This is an isometric view of the overall structure of the tail fin of this utility model, specifically according to a particular embodiment.
[0021] Figure 2 This is a partial enlarged view of a specific embodiment of the present utility model;
[0022] Figure 3 , Figure 4This is a schematic diagram of the folding component structure according to a specific embodiment of the present utility model;
[0023] Figure 5 This is a schematic diagram showing the tail fin in different states according to a specific embodiment of this utility model.
[0024] Figure labels: 1. Tail wing frame; 104. Trailing edge; 105. Leading edge; 106. Spall; 107. First reinforcing rib; 108. Elevator; 109. Second reinforcing rib; 110. Wing wall; 111. Vertical tail stabilizer; 112. Common rib; 113. Rudder; 114. Servo box; 115. Web plate; 117. Second tail wing baffle; 118. First tail wing baffle; 2. Connecting rod; 3. Folding component; 301. First fixed baffle; 302. Upper plate; 303. Second fixed baffle; 304. Side plate; 305. Lower plate; 306. Hook and latch mounting hole; 307. Hinge mounting hole. Detailed Implementation
[0025] The following is in conjunction with the appendix Figures 1 to 5 The present invention provides a more detailed description of a specific implementation of a foldable tail fin for an unmanned aerial vehicle with optimized aerodynamic performance.
[0026] The tail fin is responsible for the pitch and yaw control of an aircraft, and its structure must have sufficient strength to meet the requirements of flight. At the same time, the weight of the tail fin affects the aircraft's center of gravity and the trim situation before takeoff and during flight. Therefore, when designing the tail fin structure, it is necessary not only to ensure its necessary strength but also to control its weight as much as possible to achieve good flight performance. This utility model provides a foldable tail fin for an unmanned aerial vehicle (UAV) with optimized aerodynamic performance, including a tail fin frame 1. The tail fin frame 1 is an inverted U-shaped double vertical tail structure, including a horizontal stabilizer and two vertical stabilizer surfaces 111 on both sides. The vertical stabilizer surfaces 111 are perpendicularly connected to the horizontal stabilizer surfaces. Elevators 108 and rudders 113 are respectively installed on the vertical stabilizer surfaces 111 and the horizontal stabilizer surfaces. The tail fin frame 1 is connected to a connecting rod 2, and the end of the connecting rod 2 is connected to a folding member 3 that cooperates with the fuselage. The folding member 3 is hinged to the fuselage and equipped with a locking member to realize the folding and flipping of the tail fin.
[0027] In this preferred embodiment, the horizontal stabilizer includes a leading edge 105, a spar 106, and a trailing edge 104 arranged in parallel with each other. The tail wing frame 1 is provided with a number of ribs, which are spaced apart and span between the leading edge 105, the spar 106, and the trailing edge 104.
[0028] In this preferred embodiment, the wing rib includes a first reinforcing wing rib 107 and a second reinforcing wing rib 109, which are symmetrically installed in the middle of the tail wing frame 1. The first reinforcing wing rib 107 has a servo mounting hole, in which a horizontal tail servo connected to the elevator 108 is installed. The wing rib also includes two ordinary wing ribs 112, which are respectively installed on both sides of the first reinforcing wing rib 107 and the second reinforcing wing rib 109.
[0029] In this preferred embodiment, the rib is a symmetrical airfoil with a hollow center. The ordinary rib 112 adopts a NACA 9000 symmetrical airfoil with a thinner leading edge 105 and a relative thickness of 9.00%, with a hollow center, passing through the spar 106, with the front end (fish mouth) attached to the leading edge 105 and the rear end attached to the trailing edge 104.
[0030] In this preferred embodiment, a plurality of tail wing baffles are provided between the first reinforcing wing rib 107 and the second reinforcing wing rib 109, and the connecting rod 2 is connected to the tail wing baffles.
[0031] In a preferred embodiment, the tail fin mount 1 further includes a servo box 114, which is installed inside the vertical tail stabilizer 111 and is used to install a servo for controlling the rudder 113. The upper surface of the servo box 114 is an arc surface with the same curvature as the airfoil.
[0032] In a preferred embodiment, the wing spars 106 include symmetrically arranged upper and lower spars, with a web 115 provided on the side between the upper and lower spars. The web 115 bears and transmits the wing shear force, and both the wing spars and the web 115 are symmetrically hollowed out.
[0033] In this preferred embodiment, the folding component 3 adopts a hexahedral frame structure, including a lower plate 305 and an upper plate 302. A side plate 304 and fixed baffles 301 / 303 are provided between the upper plate 302 and the lower plate 305. The fixed baffles 301 / 303 have baffle mounting holes for installing the connecting rod 2. The folding component 3 is assembled from the upper plate, lower plate, side plate, and fixed baffles to form a hexahedral frame structure. At the same time, the two fixed baffles are at a certain angle to the horizontal plane and connected to the side plate of the folding component 3. The connecting rod 2 is fixed by adhesive bonding, thereby effectively raising the installation position of the tail fin.
[0034] In this preferred embodiment, the locking component is a latch. The upper plate of the folding component 3 has a latch mounting hole for latch installation, and the lower plate of the folding component 3 is hinged to the fuselage using a hinge. The lower plate also has a hinge mounting hole for hinge installation. The foldable connection to the fuselage is achieved through the hinge and latch. Before flight, the tail fin can be deployed from under the fuselage and secured to the fuselage via the latch on the upper side of the folding component 3. After flight, simply open the latch and fold the tail fin under the fuselage using the lower hinge (e.g., ...). Figure 5 (As shown).
[0035] In this preferred embodiment, the connecting rod 2 is angled to the horizontal direction. The fixing baffle of the folding component 3 and the tail fin baffle on the tail fin bracket 1 are both angled to the horizontal direction to raise the tail fin mounting position and avoid turbulence interference. The connecting rod 2 is a 370mm long carbon fiber tube at a 25° angle to the fuselage axis, ensuring a stable connection between the tail fin and the folding component 3.
[0036] Detailed Description: The foldable tail fin of this UAV adopts a NACA 9000 symmetrical airfoil with a thinner leading edge and a relative thickness of 9.00%. To reduce structural weight, the tail fin horizontal stabilizer also adopts a ribbed hollow design, and the wing spars are box-type structures, with the upper and lower spars made of wood. To improve structural strength, the leading edge of the tail fin horizontal stabilizer is reinforced with wooden strips, and a wing wall is provided at the trailing edge for mounting the elevator control surfaces; the wing wall material is also wood.
[0037] A tail fin baffle made of wood is constructed between the central ordinary wing ribs, with round holes for mounting connecting rods made of carbon fiber tubing. The tail fin is connected to the folding component via a carbon fiber tubing. Because the wing ribs near the carbon fiber tubing bear greater stress, this section is made of wood to increase strength. One of the reinforcing wing ribs (the first reinforcing wing rib) has a rectangular servo mounting hole in the middle for mounting the horizontal stabilizer servo, enabling control of the elevator. A servo box is located inside the vertical stabilizer surface for mounting the servo controlling the rudder; the servo box is made of wood. Except for the central first and second reinforcing wing ribs, the remaining ordinary wing ribs mainly maintain the cross-sectional shape of the horizontal stabilizer and have lower strength requirements; all are made of wood. To simplify the manufacturing process and ensure precision, the elevator is 3D printed using PLA material.
[0038] To simplify the manufacturing process and reduce structural weight, the vertical stabilizer is made entirely of wood panels, and the rudder is made entirely of wood with a weight-reducing hole in the middle.
[0039] A foldable tail fin with optimized aerodynamics, obtained through the above method, includes a tail fin support, connecting rods, and folding components. The tail fin support 1 includes a horizontal stabilizer and a vertical stabilizer 111. The horizontal stabilizer adopts a box-beam structure, specifically including interconnected tail spars 106 and tail fin ribs. The tail spars 106 are positioned at the point of greatest structural height on the airfoil section, i.e., at the 30% chord of the tail fin, thereby improving the load-bearing efficiency of the tail spars and reducing its structural weight. The structure inside the tail fin used to maintain its cross-sectional shape is the tail fin rib. The tail fin rib includes a first reinforcing rib 107, a second reinforcing rib 109, and a common rib 112. The first reinforcing rib 107 has servo mounting holes for mounting elevator servos; the second reinforcing rib 109 is mainly used to transmit concentrated loads; and the common rib 112 is used to maintain the airfoil cross-sectional shape. In addition, the leading edge 105 and wing wall 110 bear the bending axial force, while the web 115 bears and transmits the wing shear force. Overall, the main load of the UAV is transmitted by the main spars. The tail wing 1 is foldably connected to the fuselage via connecting rod 2 and folding member 3.
[0040] The connecting rod 1 is made of carbon fiber tube, and its two ends are respectively connected to the first tail fin baffle 118 and the second tail fin baffle 117 by adhesive bonding to form a stable tail fin structure support.
[0041] The folding component 3 is a hexahedral frame structure made of aviation wood, specifically assembled from side panels 304, a lower panel 305, an upper panel 302, and fixing baffles 301 / 303. The upper panel 302 of the folding component has two pairs of latch mounting holes 306, and the lower panel 305 has hinge mounting holes 307 for mounting hinges. The foldable connection to the fuselage is achieved through hinges and latches. Simultaneously, the first fixing baffle 301 and the second fixing baffle 303 are at a certain angle to the horizontal plane, connected to the side panel 304 of the folding component, and fixed to the connecting rod 104 by adhesive bonding, thereby effectively raising the installation position of the tail fin.
[0042] The elevator 108 is connected to the horizontal stabilizer via a hinge structure, and the two rudders 113 are connected to the vertical stabilizer 111 via hinge structures. The servos corresponding to the rudders 113 are installed in a pre-set servo box 114. The output end of the servo is connected to the rudders 113 via rudder arms and connecting rods to realize the drive control of the rudders 113.
[0043] The above description is merely a preferred embodiment of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are protected. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within the protection scope of this utility model.
[0044] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Specifically, the terms "first position" and "second position" refer to two different positions.
[0045] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
Claims
1. An unmanned aerial vehicle foldable tail wing that optimizes aerodynamic performance, characterized by: The tail boom is a "inverted U" type double vertical tail structure, including a horizontal tail surface and two vertical tail surfaces on both sides, the vertical tail surfaces are connected perpendicularly to the horizontal tail surface, and the vertical tail surfaces and the horizontal tail surface are respectively provided with elevators and rudders, the tail boom is connected with a connecting rod, the end of the connecting rod is connected with a folding member matched with the fuselage, the folding member is hinged to the fuselage and is provided with a locking member, and the folding of the tail is realized.
2. The unmanned aerial vehicle foldable tail wing optimizing aerodynamic performance according to claim 1, characterized in that: The horizontal tail surface comprises a front edge, a spar and a rear edge arranged in parallel with each other, and a plurality of ribs are arranged in the tail boom, and the ribs are arranged at intervals and span between the front edge, the spar and the rear edge.
3. The aerodynamic performance optimized unmanned aerial vehicle foldable tail wing according to claim 2, characterized in that: The ribs comprise first and second reinforcing ribs symmetrically arranged in the middle of the tail boom, the first reinforcing rib is provided with a rudder box mounting hole, and a horizontal tail rudder box connected with the elevator is arranged in the rudder box mounting hole, and the ribs further comprise two ordinary ribs arranged on both sides of the first and second reinforcing ribs.
4. The aerodynamic performance optimized unmanned aerial vehicle foldable tail wing according to claim 3, characterized in that: The ribs are symmetric airfoils, and the middle part is hollow.
5. The aerodynamic performance optimized unmanned aerial vehicle foldable tail wing according to claim 3, characterized in that: A plurality of tail baffles are arranged between the first and second reinforcing ribs, and the connecting rod is connected with the tail baffles.
6. The aerodynamic performance optimized unmanned aerial vehicle foldable tail wing according to claim 1, characterized in that: The tail boom further comprises a rudder box arranged in the inner side of the vertical tail surface for mounting a rudder box for controlling the rudder, and the upper surface of the rudder box is an arc surface with the same curvature as the airfoil.
7. The aerodynamic performance optimized unmanned aerial vehicle foldable tail wing according to claim 2, characterized in that: The spar comprises upper and lower beams arranged symmetrically, and a web plate is arranged between the upper and lower beams, and the web plate bears and transmits the wing shear force.
8. The aerodynamic performance optimized unmanned aerial vehicle foldable tail wing according to claim 1, characterized in that: The folding member adopts a hexahedral frame structure, comprising a lower plate and an upper plate, and a side plate and a fixed baffle are arranged between the upper and lower plates, the fixed baffle is provided with a baffle mounting hole for mounting the connecting rod.
9. The aerodynamic performance optimized unmanned aerial vehicle foldable tail wing according to claim 8, characterized in that: The locking member adopts a buckle, the upper plate of the folding member is provided with a buckle mounting hole for mounting the buckle, the lower plate of the folding member is hinged to the fuselage by a hinge, and the lower plate is provided with a hinge mounting hole for mounting the hinge, and the hinge and the buckle are connected with the fuselage to realize the foldable connection.
10. The aerodynamic performance optimized unmanned aerial vehicle foldable tail wing according to claim 1, characterized in that: The connecting rod is arranged at an angle to the horizontal direction.