A metamorphic vertical take-off and landing aircraft

Abstract

This invention provides a variable-configuration vertical takeoff and landing (VTOL) aircraft. The aircraft's wings include an inner wing fixed to the fuselage and an outer wing connected to the inner wing. The outer wing is divided into two parts, each connected to a power system, which in turn is connected to a propeller. Aerodynamic configuration changes are achieved by rotating, separating, or combining each outer wing part, allowing the aircraft to switch between VTOL and fixed-wing cruise modes. This invention avoids the shortcomings of traditional compound-wing VTOL aircraft, while simultaneously possessing the high hovering efficiency of multi-rotor aircraft and the high-speed cruise aerodynamic efficiency of fixed-wing aircraft.

Description

Technical Field

[0001] This invention belongs to the field of vertical takeoff and landing aircraft, and specifically relates to a variable configuration vertical takeoff and landing aircraft. Technical Background

[0002] Vertical takeoff and landing (VTOL) aircraft have seen rapid development in recent years due to their combination of vertical takeoff and landing (VTOL) and fixed-wing cruise advantages. Currently, common VTOL aircraft mainly include three types: compound wing aircraft, tilt-wing / powered aircraft, and tail-seat VTOL aircraft. Due to inherent drawbacks, the latter two types are currently most widely used, particularly compound wing aircraft. However, in their fixed-wing flight mode, the propulsion system used for VTOL is useless, only increasing drag. Therefore, researching a method to achieve switching between VTOL and fixed-wing cruise modes for aircraft is of great significance.

[0003] Currently, there are not many aircraft that can switch between vertical takeoff and landing (VTOL) and fixed-wing cruise modes. The few existing solutions often suffer from technical complexity or low efficiency. For example, the V-22 Osprey helicopter has the VTOL capability of a helicopter, as well as the advantages of fixed-wing propeller aircraft such as high speed, long range, and low fuel consumption. However, after many years of service, it still frequently crashes during mode switching. Summary of the Invention

[0004] The purpose of this invention is to provide a variable configuration vertical takeoff and landing (VTOL) aircraft with two flight modes: VTOL mode and fixed-wing cruise mode. It combines the advantages of VTOL functionality and the high-efficiency cruise of a fixed-wing aircraft, avoids the drag of a compound-wing aircraft's VTOL system, reduces cruise drag in fixed-wing mode, and has high air transport efficiency.

[0005] The technical solution to achieve the objective of this invention is as follows: a variable-configuration vertical takeoff and landing (VTOL) aircraft, possessing both VTOL multi-rotor and fixed-wing aircraft layouts, achieving fusion of the two layouts through configuration transformation; the wing consists of an inner wing and an outer wing, with the inner wing fixed to the fuselage and the outer wing connected to the power system, which is connected to a propeller; the outer wing is divided into two parts, and the two parts are rotated, spliced, and combined to achieve configuration transformation, thereby increasing the overall wing aspect ratio and improving the cruise flight efficiency in fixed-wing mode; both flight modes reuse a single power system, avoiding the drag of traditional compound-wing VTOL UAVs in fixed-wing cruise mode. Specifically, this is achieved through two schemes:

[0006] 1) Option 1: Thrust / pull is converted from vertical to horizontal by rotating the outer wing (around the spanwise axis, roughly parallel to the Y-axis). This can be achieved by power-driven rotation of the pivot or by forward tilting similar to a quadcopter (rotation achieved by the difference in power between the front and rear). It features three typical flight modes: vertical takeoff and landing, high-efficiency fixed-wing cruise, and high-speed cruise.

[0007] The outer wing is divided into two combined parts (which can be separated front and rear, top and bottom, or combined airfoil). Each part of the outer wing and the power system rotate around the span axis until the two parts of the outer wing are parallel to each other at a 180-degree angle in the Z-axis direction, realizing the conversion of thrust / pull from the vertical direction to the horizontal direction, i.e., high-speed cruise mode; then the two parts of the outer wing rotate symmetrically in opposite directions around the chord axis until the angle is 0 degrees, to the fixed-wing cruise mode. In the fixed-wing cruise mode, they are combined to form a complete outer wing, and the power system connected to the outer wing rotates synchronously in the thrust direction.

[0008] 2) Option 2: The thrust direction change adopts a tilt mode, which achieves the matching of thrust direction between vertical take-off and landing mode and fixed-wing mode by tilting the thrust direction;

[0009] The outer wing can be divided into two parts (which can be separated and combined into an airfoil pattern), and rotate in opposite directions around the root axis of the outer wing (lift direction, roughly parallel to the Z-axis). The power system tilts synchronously to achieve this. In fixed-wing cruise mode, the two parts are combined to form a complete outer wing. The power system connected to the outer wing rotates in coordination with the thrust direction.

[0010] Furthermore, the power system can be directly mounted on the wing, or the power source can be transmitted to the wingtip via a drive shaft.

[0011] Furthermore, if the power system uses propeller power and adopts a coaxial arrangement, it can improve high-speed aerodynamic efficiency and reduce the total thrust of the propeller system to meet the needs of high thrust during takeoff and landing and relatively low thrust during cruise. If the power system uses turbojet engines, their positions should be staggered and not supplied to the shaft to avoid mutual interference of the thrust systems.

[0012] Furthermore, the power system can be installed at the wingtip of the outer wing or at the middle section of the outer wing, which can further increase the wing aspect ratio and improve cruise efficiency.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] (1) This invention has two flight modes: vertical take-off and landing mode and fixed-wing cruise mode, which improves the wing aspect ratio and enhances cruise efficiency.

[0015] (2) The present invention has two sets of propellers on one side forming a coaxial reversing configuration, which improves the efficiency of the propulsion system during high-speed flight;

[0016] (3) This invention avoids drag in the vertical take-off and landing system of compound wing aircraft and reduces cruise drag in fixed wing mode;

[0017] (4) The power system of the take-off and landing mode and the fixed-wing cruise mode of the present invention is reused, which avoids unnecessary multiple power systems;

[0018] (5) The outer wing of the present invention can be rotated and folded to reduce the space occupied by the aircraft when it lands on the ground. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the vertical take-off and landing mode in Example 1.

[0020] Figure 2 This is a schematic diagram of the fixed-wing cruise mode in Example 1.

[0021] Figure 3 This is a schematic diagram of the intermediate transformation configuration state ① of Example 1.

[0022] Figure 4 This is a schematic diagram of the intermediate transformation configuration state ② high-speed cruise mode in Example 1.

[0023] Figure 5 This is a schematic diagram of intermediate configuration state ③ in Example 1.

[0024] Figure 6 This is a schematic diagram of the intermediate transformation shaft in Example 1.

[0025] Figure 7 This is a schematic diagram of the vertical take-off and landing mode in Example 2.

[0026] Figure 8 This is a schematic diagram of the fixed-wing cruise mode in Example 2.

[0027] Figure 9 This is a schematic diagram of the intermediate transformation configuration state ① in Example 2.

[0028] Figure 10 This is a schematic diagram of intermediate transformation configuration state ② in Example 2.

[0029] Figure 11 This is a schematic diagram of the rotating shaft in Example 2.

[0030] Figure 12 This is a schematic diagram of the airfoil combination method in the embodiment, wherein Figure 12 (a) is a schematic diagram of the front and rear planes of the airfoil. Figure 12 (b) Schematic diagram of the leading edge of the rear half of the airfoil, showing the segmentation of the airfoil arc. Figure 12 (c) is a schematic diagram of the upper and lower planes of the airfoil. Figure 12 (d) is a schematic diagram of two relatively complete airfoils formed by dividing the airfoil curve. Detailed Implementation

[0031] Example 1

[0032] This invention relates to a variable-configuration vertical takeoff and landing (VTOL) aircraft, consisting of a conventional fixed-wing aircraft fuselage, an inner wing section, and a variable-configuration outer wing section, a propulsion system, and a mode-changing mechanism. It enables the separation, rotation, and combination of the two wing sections of the outer wing, and the adjustment of the thrust direction of the propulsion system. The main components are as follows: Figure 1 As shown, the inner wing is 1, the fuselage is 2, the tail is 3, the left front outer wing is 4, the left rear outer wing is 5, the left front power system is 6, the left rear power system is 7, and the first mode conversion mechanism is 8. Since the fuselage is symmetrical, for the sake of simplifying the diagram, one component is only labeled on one side.

[0033] The inner wing 1, fuselage 2, and tail 3 constitute a traditional fixed-wing aircraft structure. The landing gear, ailerons, elevators, rudders, etc., in the aircraft structure are not illustrated as they are common knowledge in the field and do not affect the description of this invention; therefore, they will not be elaborated upon here. The inner wing is fixedly connected to the fuselage and has no relative movement with it.

[0034] The outer wing is divided into two parts: the left front outer wing 4 and the left rear outer wing 5. The right side is symmetrically divided into a right front outer wing and a right rear outer wing. The left front power system 6 and the left rear power system 7 also have symmetrical parts on the right side. The left front power system 6 and the left rear power system 7 are connected to the left front outer wing 4 and the left rear outer wing 5, respectively. A first mode-changing mechanism 8 connects the inner wing and the outer wing, driving the outer wing and the power system to perform aerodynamic configuration changes together. Figure 1 Vertical takeoff and landing modes and Figure 2 Switching between fixed-wing cruise modes.

[0035] To illustrate the mode transformation process, three intermediate process diagrams are drawn, such as... Figure 3-5 As shown, this is the vertical takeoff and landing mode from the ground. Figure 1 —> Figure 3 —> Figure 4 —> Figure 5 —> Figure 2 The process of switching between fixed-wing cruise modes, in reverse order, is the transition from fixed-wing cruise mode to vertical takeoff and landing mode, completing the process of cruise and landing from the air. This embodiment can achieve... Figure 1 The vertical takeoff and landing mode shown Figure 2 The fixed-wing high-efficiency cruise mode shown Figure 4 The high-speed cruise mode shown.

[0036] Figure 1 —> Figure 3 —> Figure 4In vertical takeoff and landing mode, the aircraft vertically ascends to the predetermined flight altitude for mode transition. The left front outer wing 4 and the left rear outer wing 5 maintain a constant parallel angle and, together with the left front power system 6 and the left rear power system 7, gradually rotate around the spanwise axis 10 of the wings (axis 10 is an auxiliary line for steering illustration, basically parallel to the Y-axis of the fuselage). During this process, due to the thrust components of the left front power system 6 and the left rear power system 7 along the fuselage, the aircraft gradually establishes forward flight speed, and the inner wing 1 generates gradually increasing aerodynamic lift. The demand for lift from the power system gradually decreases, eventually reaching... Figure 4 In the high-speed cruise mode, the aircraft reaches a high speed, and the lift is generated entirely by the inner wing. The thrust generated by the left front power system 6 and the left rear power system 7 is parallel to the rear of the fuselage X-axis.

[0037] Figure 4 —> Figure 5 —> Figure 2 ,Depend on Figure 4 In the initial state, the left front outer wing 4 and the left rear outer wing 5 rotate symmetrically in opposite directions around the chordal rotation axis 9 (the chordal rotation axis 9 is an auxiliary line for steering, parallel to the X-axis), gradually decreasing the 180-degree angle from the parallel state until... Figure 5 The angle is reduced from 90 degrees to 0 degrees. The left front outer wing 4 and the left rear outer wing 5 are spliced ​​together to form a complete outer wing, which, together with the inner wing, generates lift in fixed-wing mode. The left front power system 6 and the left rear power system 7 are coaxial, which can improve the propeller system's propulsion efficiency. If the power source is a turbojet engine or similar type, a coaxial arrangement is not suitable, and the two power sources need to be staggered, for example, one located on the upper wing and the other under the wing.

[0038] Figure 6 The two rotation axes of the outer wing are shown, both in the direction of the drawing auxiliary lines. The rotation of the outer wing around these two rotation axes can be achieved by the first mode-changing mechanism 8. The left front power system 6 and the left rear power system 7 can be rotating servo motors, etc. The first mode-changing mechanism 8, which enables the outer wing to rotate around the two rotation axes, can be implemented using conventional technology. For example, a rotating shaft can be provided at the connection between the inner wing and the outer wing. This rotating shaft can rotate around the spanwise axis. The outer wing is rotatably connected to the rotating shaft and can rotate around the chordwise axis. Therefore, the specific implementation of the first mode-changing mechanism 8 will not be described in detail here.

[0039] Example 2

[0040] This embodiment employs an in-plane rotation scheme for the outer wing, with the power system tilting synchronously. The difference from Embodiment 1 lies in the mode-changing mechanism; for example... Figure 7 , 8As shown, the mode conversion mechanism includes a second mode conversion mechanism 11, a third mode conversion mechanism 12 for the left front power system 6, and a fourth mode conversion mechanism 13 for the left rear power system 7. The second mode conversion mechanism 11 realizes the combination and separation of the outer wings in the horizontal plane, and the third mode conversion mechanism 12 and the fourth mode conversion mechanism 13 realize the rotation of the power system around the spanwise axis to achieve the change of thrust direction.

[0041] To illustrate the mode transformation process, two intermediate process diagrams are drawn, as follows: Figure 9-10 As shown, the vertical takeoff and landing mode from the ground. Figure 7 —> Figure 9 —> Figure 10 —> Figure 8 The process of changing fixed-wing cruise mode, when reversed, is the transition from fixed-wing cruise mode to vertical takeoff and landing mode, completing the process of cruise and landing from the air.

[0042] Figure 7 —> Figure 9 —> Figure 10 —> Figure 8 In vertical takeoff and landing mode, the aircraft vertically ascends to the predetermined mode-transition flight altitude. The left front outer wing 4 and the left rear outer wing 5 rotate synchronously in opposite directions around the first rotation axis 16 and the second rotation axis 17 (rotation axes in the horizontal plane of the outer wing, parallel to the Z-axis) respectively through the second mode-transition mechanism 11, with the included angle gradually decreasing until they are completely merged into an integrated outer wing. The left front power system 6 and the left rear power system 7 rotate around the third rotation axis 18 and the fourth rotation axis 19 (along the spanwise direction of the outer wing) respectively through the third mode-transition mechanism 12 and the fourth mode-transition mechanism 13, gradually converting the vertically downward thrust into a rearward thrust. During this process, as the rearward thrust components of the left front power system 6 and the left rear power system 7 along the fuselage continuously increase, the aircraft gradually establishes forward flight speed, and the inner wing 1 generates a gradually increasing aerodynamic lift. The demand for lift from the power system gradually decreases, eventually reaching the desired speed. Figure 8 Fixed-wing cruise mode. First pivot axis 16, second pivot axis 17, third pivot axis 18, fourth pivot axis 19 as shown. Figure 11 As shown.

[0043] The rotation of the second mode conversion mechanism 11, the third mode conversion mechanism 12 of the left front power system 6, and the fourth mode conversion mechanism 13 of the left rear power system 7 is a conventional technique in the art. For example, the inner wing end is equipped with a shaft parallel to the Z-axis direction, and the root of the outer wing is rotatably connected to the shaft. Therefore, its specific implementation will not be described here.

[0044] There are several ways to divide the outer wing into two parts, such as airfoil segmentation combinations. Figure 12As shown, this diagram illustrates four airfoil configurations. The centerline of the airfoil serves as a dividing line, which can be broadly categorized into two types based on its position: front-to-back split and top-to-bottom split. Front-to-back splits maintain the airfoil's thickness, while top-to-bottom splits result in a thinner airfoil with less drag in the downdraft compared to front-to-back splits. Figure 12 (a) shows the front and rear plane division of the airfoil. Figure 12 (b) The leading edge of the rear half of the airfoil is retained for the airfoil arc segmentation. Figure 12 (c) is the division of the upper and lower planes of the airfoil. Figure 12 (d) The airfoil curve is divided to form two relatively complete airfoils.

[0045] Note: The coordinate axes are defined as follows: X-axis forward along the aircraft axis, Y-axis to the right along the aircraft axis, Z-axis downward along the aircraft axis, and left and right are defined as looking from the tail of the aircraft towards the nose.

[0046] This invention proposes a variable configuration vertical takeoff and landing (VTOL) aircraft, which is a high-efficiency VTOL aircraft with two flight modes: VTOL and fixed-wing cruise. In VTOL mode, it is a quadcopter, while in cruise mode, it is a fixed-wing aircraft. Both flight modes share a single power system. The outer section of the wing is divided into two wings during VTOL, which are combined to form a complete wing in fixed-wing mode. Through the rotation, splicing, and combination of the wings, the aerodynamic configuration of the two modes can be changed in the air. This invention avoids the shortcomings of traditional compound VTOL aircraft and simultaneously possesses the high hovering efficiency of multi-rotor aircraft and the high-speed cruise flight aerodynamic efficiency of fixed-wing aircraft.

Claims

1. A variable-configuration vertical takeoff and landing aircraft, characterized in that, The aircraft's wings include an inner wing fixed to the fuselage and an outer wing connected to the inner wing. The outer wing is divided into two parts, each of which is connected to a power system. The power system is connected to a propeller. The aerodynamic configuration can be transformed by rotating, separating, or splicing and combining each part of the outer wing, so that the aircraft can switch between vertical take-off and landing mode and fixed-wing cruise mode. The transition between the vertical takeoff and landing mode and the fixed-wing cruise mode includes: rotating each part of the outer wing and the power system as a whole around the spanwise axis until the two parts of the outer wing are parallel to each other at a 180-degree angle in the Z-axis direction, realizing the conversion of thrust / pull from the vertical direction to the horizontal direction, i.e., high-speed cruise mode; then rotating the two parts of the outer wing symmetrically in opposite directions around the chord axis until the angle is 0 degrees, to the fixed-wing cruise mode.

2. The variable configuration vertical takeoff and landing aircraft according to claim 1, characterized in that, The inner wing and the outer wing are connected by a pivot, which can rotate about the spanwise axis. The outer wing is rotatably connected to the pivot and can rotate about the pivot in the chordwise direction.

3. A variable configuration vertical takeoff and landing aircraft, characterized in that, The aircraft's wings include an inner wing fixed to the fuselage and an outer wing connected to the inner wing. The outer wing is divided into two parts, each of which is connected to a power system. The power system is connected to a propeller. The aerodynamic configuration can be transformed by rotating, separating, or splicing and combining each part of the outer wing, so that the aircraft can switch between vertical take-off and landing mode and fixed-wing cruise mode. The switching between the vertical takeoff and landing mode and the fixed-wing cruise mode is achieved by rotating the outer wing in the horizontal plane and tilting the power system synchronously. The specific transition between the vertical takeoff and landing mode and the fixed-wing cruise mode includes: each part of the outer wing rotates in the opposite direction around the Z-axis until the included angle is 0 degrees, the power system rotates around the direction axis along the span of the outer wing, and gradually converts the vertical downward thrust to the rearward thrust, thus switching to the fixed-wing cruise mode.

4. The variable configuration vertical takeoff and landing aircraft according to claim 3, characterized in that, The inner wing end is equipped with a shaft parallel to the Z-axis direction, and the outer wing end is rotatably connected to this shaft.

5. The variable configuration vertical takeoff and landing aircraft according to any one of claims 1 to 4, characterized in that, The power system is either directly mounted on the outer wing or connected to the outer wing via a drive shaft.

6. The variable configuration vertical takeoff and landing aircraft according to any one of claims 1 to 4, characterized in that, The outer wing is divided into two parts as follows: the centerline of the airfoil is used as the dividing line, and the wing is divided into front and rear sections and upper and lower sections. The front and rear sections maintain the thickness of the airfoil, while the upper and lower sections have thinner airfoils, resulting in less drag from the airflow than the front and rear sections.

7. The variable configuration vertical takeoff and landing aircraft according to claim 6, characterized in that, The dividing line can be a straight line, an arc, or a curve.

8. The variable configuration vertical takeoff and landing aircraft according to any one of claims 1 to 4, characterized in that, The power system uses a turbojet engine. In fixed-wing cruise mode, the power systems connected to the two outer wings are not coaxial.

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