Tandem wing-joint wing ground effect vehicle

Abstract

A tandem wing-coupled wing ground effect vehicle comprises a fuselage, a front wing, a rear wing, a coupled wing, an engine, a tail wing and a float; the height position relationship of the front wing and the rear wing satisfies that the ratio of the height of the front wing to the water surface to the average aerodynamic chord length of the front wing is equal to the ratio of the height of the rear wing to the water surface to the average aerodynamic chord length of the rear wing in the cruising state; the front-rear position relationship of the front wing and the rear wing satisfies that the ratio of the front-rear distance between the average aerodynamic chord focus point of the front wing and the center of gravity of the vehicle to the front-rear distance between the average aerodynamic chord focus point of the rear wing and the center of gravity of the vehicle is equal to the square of the ratio of the average aerodynamic chord length of the rear wing to the average aerodynamic chord length of the front wing. The height position relationship and the front-rear position relationship of the front wing and the rear wing are reasonably configured, the longitudinal control and stability characteristics of the whole vehicle are enhanced, the technical problem that the traditional layout ground effect vehicle is prone to losing control due to the additional pitch moment increment generated when the flight height changes is solved, the lateral and horizontal maneuverability of the whole vehicle is greatly enhanced, the carrying capacity is improved, and higher carrying efficiency is achieved.

Description

Technical Field

[0001] This invention belongs to the field of aerodynamic layout design technology for aircraft, and specifically relates to a tandem wing-connected wing ground effect vehicle. Background Technology

[0002] The phenomenon where an aircraft's lift-to-drag ratio increases and induced drag decreases when flying close to the ground or water surface is called the ground effect. The flight altitude at which the ground effect occurs is within a certain range, known as the ground effect zone. A ground effect vehicle (GEV) is a new type of transportation that utilizes the ground effect principle to fly within the ground effect zone, close to the ground or water surface, with performance falling between that of ships and conventional aircraft. With its high cruising speed, high lift-to-drag ratio, high carrying efficiency, and good economy, the GEV has broad application prospects in both military and civilian fields.

[0003] However, when a ground effect vehicle (GEV) flies in the ground effect zone, changes in flight altitude will cause changes in the aerodynamic forces of the entire aircraft. For GEVs with traditional layouts such as single main wings, there is a technical problem that changes in flight altitude can easily generate additional pitching moment increments, which can lead to loss of control of the aircraft and affect flight safety.

[0004] In addition, since the altitude range of the ground effect zone is relatively small, often equal to or less than the wing chord, for ground effect vehicles cruising in it, adopting traditional layouts such as single main wing will result in limited maneuverability due to the excessively long main wing span relative to the flight altitude. This makes it impossible to achieve lateral maneuverability in the ground effect zone through methods such as fuselage roll, resulting in poor lateral maneuverability. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of existing technologies and provide a tandem-wing-connected-wing ground effect vehicle. By rationally configuring the altitude and fore-aft position relationships of the front and rear wings, the longitudinal handling stability of the entire aircraft is enhanced, solving the technical problem that the additional pitch moment increase generated when the flight altitude changes in traditional ground effect vehicles easily leads to loss of control, thus ensuring flight safety. With the front wing below and the rear wing above, and the front wing short and the rear wing long, the aircraft can achieve lateral maneuvering through fuselage roll during cruise in the ground effect zone, greatly enhancing the lateral maneuverability of the entire aircraft. The tandem-wing-connected-wing layout achieves a closed wing configuration, further improving aerodynamic efficiency, while reducing empty weight, increasing carrying capacity, and achieving higher carrying efficiency.

[0006] The technical solution provided by this invention is as follows:

[0007] A tandem-wing-connected-wing ground effect vehicle includes: a fuselage, a canard, a rear wing, and a tandem wing;

[0008] The forewing is mounted on the lower front of the fuselage, and the rear wing is mounted on the upper rear of the fuselage; the forewing and rear wing have the same airfoil, the same tip-root ratio, and the same aspect ratio, but the span of the forewing is shorter than that of the rear wing.

[0009] The height relationship between the canard and the rear wing satisfies the following: In cruise mode, the ratio of the height h1 of the canard above the water surface to the average aerodynamic chord c1 of the canard is equal to the ratio of the height h2 of the rear wing above the water surface to the average aerodynamic chord c2 of the rear wing.

[0010] The fore-and-aft positional relationship between the canard and the rear wing satisfies the following: the axial distance between the average aerodynamic chord focus of the canard and the center of gravity of the aircraft is d1, the axial distance between the average aerodynamic chord focus of the rear wing and the center of gravity of the aircraft is d2, and the ratio of d1 to d2 is equal to the square of the ratio of c2 to c1.

[0011] The connecting wing connects the front wing and the rear wing, with its two ends fixedly connected to the wingtip of the front wing and the middle of the rear wing, respectively. The chord of any airfoil section of the connecting wing is parallel to the fuselage axis.

[0012] Furthermore, the aircraft also includes an engine, a tail fin, and floats;

[0013] The engine is located at the front of the fuselage, axially in front of the canard; the tail is located at the rear of the fuselage; and floats are located at both ends of the canard.

[0014] Furthermore, the fuselage has an integrated aircraft fuselage-ship hull layout, with the upper half of the fuselage being the aircraft fuselage and the lower half being the ship hull, and a step is provided in the middle of the ship hull;

[0015] Before the step, the hull chord line within the first distance L1 is parallel to the fuselage axis, and the bottom of the cross-section is V-shaped; after the step, the hull chord line within the second distance L2 forms an angle α with the fuselage axis, and the bottom of the cross-section gradually transitions from V-shaped to straight; the hull chord line at the stern forms an angle β with the fuselage axis, and the bottom of the cross-section is straight.

[0016] Furthermore, the first distance L1 is no less than 1.5 times the fuselage width; the second distance L2 is no more than 0.5 times the total length of the aircraft.

[0017] Furthermore, the included angle α ranges from 7° to 9°; the included angle β ranges from α ≤ β ≤ 45°.

[0018] Furthermore, the forewing is a trapezoidal wing with a tip-to-root ratio of 0.4 to 0.5, and forewing flaps are installed on the trailing edge of the forewing.

[0019] Furthermore, the rear wing is a trapezoidal wing with a tip-to-root ratio of 0.4 to 0.5.

[0020] Furthermore, the airfoil of the connected wings is a symmetrical airfoil.

[0021] Furthermore, the float is installed below the wingtip of the forewing; the tail fin is a V-shaped tail fin, installed above the tail of the fuselage, and the included angle between the tail fins does not exceed 90°.

[0022] Furthermore, the engine is installed at a height higher than the forewing and lower than the rearwing; the rear of the engine is provided with an airflow direction adjustment device, which can deflect the airflow direction after the engine nozzle so that it flows over the forewing or into the power air cushion cavity below the forewing.

[0023] The so-called powered air cushion cavity refers to the cavity composed of the lower fuselage, the lower surface of the canard, the downward-deflected canard flaps, the floats, and the water surface.

[0024] The tandem-wing-connected-wing ground effect vehicle provided by the present invention has the following beneficial effects:

[0025] (1) The present invention provides a tandem wing-connected wing ground effect vehicle, which, by reasonably configuring the height position relationship and front-rear position relationship of the front and rear wings, ensures that the ground effect vehicle does not generate additional pitch moment increment when the cruise flight altitude changes, thereby enhancing the longitudinal handling stability of the entire aircraft. It solves the technical problem that the additional pitch moment increment generated when the flight altitude of the traditional layout ground effect vehicle changes, which makes the aircraft prone to loss of control, and ensures flight safety.

[0026] (2) The present invention provides a tandem wing-connected wing ground effect vehicle, which, through the layout of the forewing below and the rear wing above, with the forewing being short and the rear wing being long, can achieve lateral maneuvering by the fuselage roll during cruise in the ground effect zone, greatly enhancing the lateral maneuverability of the entire aircraft.

[0027] (3) The tandem wing-connected wing ground effect vehicle provided by the present invention achieves a closed wing configuration through the tandem wing-connected wing layout, which further reduces induced drag, increases lift-to-drag ratio, and improves the aerodynamic efficiency of the ground effect vehicle; at the same time, the wing size is smaller, the structural weight is lighter, and the rigidity is greater, which further reduces the empty weight, improves the carrying capacity, and achieves higher carrying efficiency. Attached Figure Description

[0028] Figure 1 This is a top view schematic diagram of the tandem wing-connected wing ground effect vehicle of the present invention;

[0029] Figure 2 This is a side view schematic diagram of the tandem wing-connected wing ground effect vehicle of the present invention;

[0030] Figure 3 This is a front view schematic diagram of the tandem wing-connected wing ground effect vehicle of the present invention;

[0031] Figure 4 This is a schematic diagram showing the average aerodynamic chord length and height above the water surface of the fore wing and rear wing in this invention;

[0032] Figure 5 This is a schematic diagram showing the distance between the average aerodynamic chord focus of the forewing and the rear wing and the center of gravity of the aircraft, and the average aerodynamic chord length in this invention.

[0033] Figure 6 This is a schematic diagram of the cross-section of the fuselage within the first distance L1 before the step break, within the second distance L2 after the step break, and the tail section in this invention.

[0034] Explanation of icon numbers

[0035] 1-Fuselage; 1-1-Step; 2-Engine; 2-1-Airflow control device; 3-Canard; 3-1-Canard flap; 4-Connecting wing; 5-Rear wing; 6-Tail wing; 7-Float. Detailed Implementation

[0036] The features and advantages of the present invention will become clearer and more explicit from the following detailed description.

[0037] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0038] like Figures 1-6 As shown, this invention provides a tandem-wing ground effect vehicle, comprising a fuselage 1, a canard 3, a rear wing 5, a tandem wing 4, an engine 2, a tail fin 6, and floats 7. Specific components are detailed below. Figure 1 As shown.

[0039] The forewing 3 is mounted on the lower front of the fuselage 1, and the rear wing 5 is mounted on the upper rear of the fuselage 1. Figure 2 The fore wing 3 and the rear wing 5 have the same airfoil, the same tip-root ratio, and the same aspect ratio, but the span of the fore wing 3 is less than the span of the rear wing 5. The altitude relationship between the fore wing 3 and the rear wing 5 satisfies the following: In cruise mode, the ratio of the height h1 of the fore wing 3 above the water surface to the average aerodynamic chord length c1 of the fore wing 3 is equal to the ratio of the height h2 of the rear wing 5 above the water surface to the average aerodynamic chord length c2 of the rear wing 5. (See...) Figure 4 The fore-aft positional relationship between the canard 3 and the aft wing 5 satisfies the following: the ratio of the fore-aft distance d1 of the average aerodynamic chord focus of the canard 3 to the fore-aft distance d2 of the average aerodynamic chord focus of the aft wing 5 to the aft wing 5 to the center of gravity is equal to the square of the ratio of the average aerodynamic chord length c2 of the aft wing 5 to the average aerodynamic chord length c1 of the canard 3. (See...) Figure 5 ;

[0040] The connecting wing 4 is fixedly connected to the wingtip of the forewing 3 and the middle of the rear wing 5, and the chord of any airfoil section of the connecting wing 4 is parallel to the axis of the fuselage 1.

[0041] In a preferred embodiment, the fuselage 1 has an integrated aircraft fuselage-ship hull layout, with the upper part being the aircraft fuselage and the lower part being the ship hull. A step 1-1 is provided in the middle of the ship hull. Figure 2 The hull chord line within the first distance L1 (not less than 1.5 times the fuselage width) before step 1-1 is parallel to the fuselage 1 axis, and the bottom of the cross-section is V-shaped; the hull chord line within the second distance L2 (not greater than 0.5 times the total length of the aircraft) after step 1-1 forms an angle α (7°~9°) with the fuselage 1 axis, and the bottom of the cross-section gradually transitions from V-shaped to straight; the hull chord line at the stern forms an angle β (α≤β≤45°) with the fuselage 1 axis, and the bottom of the cross-section is straight, see... Figure 6 .

[0042] In a preferred embodiment, the forewing 3 is a trapezoidal wing with a tip-to-root ratio of 0.4 to 0.5, and a forewing flap 3-1 is installed on the trailing edge of the forewing 3. Figure 1 .

[0043] In a preferred embodiment, the rear wing 5 is a trapezoidal wing with a tip-to-root ratio of 0.4 to 0.5.

[0044] In a preferred embodiment, the airfoil of the connecting wing 4 is a symmetrical airfoil.

[0045] In a preferred embodiment, the float 7 is mounted below the wingtip of the forewing 3, see... Figure 1 .

[0046] In a preferred embodiment, the engine 2 is installed at the front of the fuselage 1, in front of the forewing 3, and the installation height of the engine 2 is higher than the forewing 3 and lower than the rear wing 5; the rear of the engine 2 is provided with an airflow direction adjustment device 2-1, which can deflect the airflow direction after the engine nozzle so that it flows over the forewing 3 or flows into the power air cushion cavity below the forewing 3.

[0047] The power air cushion cavity refers to the cavity composed of the lower part of the fuselage 1, the lower wing surface of the forewing 3, the downward-deflected forewing flap 3-1, the float 7, and the water surface.

[0048] In a preferred embodiment, the tail fin 6 is a V-shaped tail fin, installed above the tail of the fuselage 1, and the included angle between the tail fins does not exceed 90°.

[0049] The longitudinal handling stability principle of a tandem-wing ground effect vehicle is as follows:

[0050] By controlling the front and rear wings to use the same airfoil, same tip-root ratio, and same aspect ratio, the aerodynamic characteristics, such as lift coefficient, of the front and rear wings are ensured to be consistent under the same conditions. Furthermore, by designing the altitude position relationship, the ratio of the average aerodynamic chord length of the front and rear wings to the height above the water surface is made equal during cruise, ensuring consistent aerodynamic characteristics of the front and rear wings in the ground effect zone. Finally, by rationally configuring the fore-and-aft position relationship of the front and rear wings, the magnitude of the aerodynamic force increments generated by the front and rear wings about the center of gravity is equal and the direction is opposite, so they can cancel each other out. This ensures that no additional pitch moment increment is generated when the flight altitude of the ground effect vehicle changes, thereby enhancing longitudinal handling stability and ensuring flight safety.

[0051] The principle of the lateral maneuvering characteristics of a tandem-wing ground effect vehicle is as follows:

[0052] With a configuration where the forewing is below and the rear wing is above, and the forewing is short and the rear wing is long, the ground effect vehicle (GEV) can achieve fuselage roll within the ground effect zone. In this configuration, the aerodynamic forces acting on the GEV can be decomposed into a centripetal force in the lateral direction, thus enabling lateral maneuvering. Because the forewing is short, this configuration avoids the safety concerns associated with traditional configurations like single-wing designs where an excessively long main wing can cause water splashing during fuselage roll. Furthermore, this configuration allows for a larger fuselage roll angle, significantly enhancing lateral maneuverability.

[0053] In this embodiment, both the forewing 3 and the rear wing 5 adopt the same airfoil (preferably, an airfoil with a relatively flat lower surface, such as the NACA4412 airfoil), with a tip-root ratio of 0.5 and an aspect ratio of 7.5. The forewing 3 has a span of 18.75m and a mean aerodynamic chord of 2.5m. The rear wing 5 has a forward sweep angle of 30°, a span of 37.65m, and a mean aerodynamic chord of 5.01m. In cruise mode, the forewing 3 is 3.75m above the water surface, and the rear wing 5 is 7.52m above the water surface. The aircraft has an overall length of 41.2m, and its center of gravity is located at 50.9% of the total length. The distance from the mean aerodynamic chord focus of the forewing 3 to the front-to-back distance of the aircraft's center of gravity is 9.38m, and the distance from the mean aerodynamic chord focus of the rear wing 5 to the front-to-back distance of the aircraft's center of gravity is 2.33m. The connecting wing 4 adopts a symmetrical airfoil, specifically the NACA0009 airfoil. The fuselage width is 5m. The first distance L1 before step 1-1 is 12.1m, and the second distance L2 after step 1-1 is 9.31m. The included angle α is 9°, and the included angle β is 25°. The included angle between the tail fins is 60°.

[0054] The above parameters were obtained through detailed theoretical calculations and numerical analysis to achieve a reasonable design of the aircraft's aerodynamic parameters.

[0055] In this invention, "forward" refers to the direction along the fuselage axis from the tail of the aircraft to the nose of the aircraft, and correspondingly, "backward" refers to the direction along the fuselage axis from the nose of the aircraft to the tail of the aircraft.

[0056] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0057] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A tandem-wing-connected-wing ground effect vehicle, characterized in that, include: The fuselage (1), canard (3), rear wing (5), and wing-connecting (4); The forewing (3) is mounted on the lower front of the fuselage (1), and the rear wing (5) is mounted on the upper rear of the fuselage (1); the forewing (3) and the rear wing (5) have the same airfoil, the same tip-to-root ratio, and the same aspect ratio, and the span of the forewing (3) is less than the span of the rear wing (5). The height relationship between the front wing (3) and the rear wing (5) satisfies the following: the ratio of the height h1 of the front wing (3) above the water surface to the average aerodynamic chord length c1 of the front wing (3) in cruise mode is equal to the ratio of the height h2 of the rear wing (5) above the water surface to the average aerodynamic chord length c2 of the rear wing (5). The front-to-back positional relationship between the fore-wing (3) and the rear-wing (5) satisfies the following: the axial distance between the average aerodynamic chord focus of the fore-wing (3) and the center of gravity of the aircraft is d1, the axial distance between the average aerodynamic chord focus of the rear-wing (5) and the center of gravity of the aircraft is d2, and the ratio of d1 to d2 is equal to the square of the ratio of c2 to c1. The connecting wing (4) connects the front wing (3) and the rear wing (5), and its two ends are fixedly connected to the wingtip of the front wing (3) and the middle part of the rear wing (5) respectively. The chord of any airfoil section of the connecting wing (4) is parallel to the axis of the fuselage (1). The fuselage (1) is an aircraft fuselage-ship fusion layout. The upper part of the fuselage (1) is the aircraft fuselage, and the lower part is the ship hull. The middle part of the ship hull has a step (1-1). The hull chord line within the first distance L1 before the step (1-1) is parallel to the axis of the fuselage (1), and the bottom of the cross-section is V-shaped. The hull chord line within the second distance L2 after the step (1-1) forms an angle α with the axis of the fuselage (1), and the bottom of the cross-section gradually transitions from V-shaped to straight. The chord line at the tail of the ship forms an angle β with the axis of the fuselage (1), and the bottom of the cross-section is straight. The forewing (3) is a trapezoidal wing with a tip-to-root ratio of 0.4 to 0.5, and a forewing flap (3-1) is installed on the trailing edge of the forewing (3); the rear wing (5) is a trapezoidal wing with a tip-to-root ratio of 0.4 to 0.5; the connecting wing (4) has a symmetrical airfoil.

2. The tandem-wing-connected-wing ground effect vehicle according to claim 1, characterized in that: It also includes an engine (2), a tail fin (6), and floats (7); The engine (2) is located at the front of the fuselage (1) and is axially located in front of the forewing (3); the tail fin (6) is located at the rear of the fuselage (1); and floats (7) are also provided at both ends of the forewing (3).

3. A tandem-wing-connected-wing ground effect vehicle according to claim 1, characterized in that: The first distance L1 is no less than 1.5 times the fuselage width; the second distance L2 is no more than 0.5 times the total length of the aircraft.

4. A tandem-wing ground effect vehicle according to claim 1, characterized in that: The included angle α ranges from 7° to 9°; the included angle β ranges from α ≤ β ≤ 45°.

5. A tandem-wing-connected-wing ground effect vehicle according to claim 2, characterized in that: The float (7) is installed below the wingtip of the forewing (3); the tail fin (6) is a V-shaped tail fin, installed above the tail of the fuselage (1), and the included angle between the tail fins does not exceed 90°.

6. A tandem-wing-connected-wing ground effect vehicle according to claim 2, characterized in that: The engine (2) is installed at a height higher than the front wing (3) and lower than the rear wing (5); the engine (2) is provided with an airflow direction adjustment device (2-1) at the rear, which can deflect the airflow direction after the engine nozzle so that it flows over the front wing (3) or flows into the power air cushion cavity below the front wing (3). The power air cushion cavity refers to the cavity composed of the lower part of the fuselage (1), the lower wing surface of the forewing (3), the downward-deflected forewing flap (3-1), the float (7), and the water surface.

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