Non-orthogonal tilt-rotor aircraft and flight control method thereof

Abstract

The invention provides a non-orthogonal tilt-rotor aircraft and a flight control method thereof, a tilt shaft at the lower end of a tilt nacelle is obliquely arranged, and the tilt shaft is parallel to an XZ plane, forms an angle of 45 degrees with an X axis and a Z axis, and is not orthogonal to an XY plane and a YZ plane of a fuselage coordinate system; the positive direction of the X axis is backward along the course, the positive direction of the Y axis is rightward along the course, and the positive direction of the Z axis is upward along the vertical direction. According to the invention, the transverse stability augmentation effect can be provided, the transverse stability is improved, and the problem of unstable pitching of the fuselage caused by tilting of the rotor nacelles can be avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of tiltrotor aircraft, and in particular relates to a non-orthogonal tiltrotor aircraft and a flight control method thereof. Background Art

[0002] A tilt-rotor aircraft is a new type of aircraft that integrates a fixed-wing aircraft and a helicopter. It has the ability of vertical take-off and landing and hovering in the air like an ordinary helicopter, as well as the ability of high-speed cruising flight like a fixed-wing aircraft.

[0003] The existing tilt-rotor aircraft have poor lateral stability due to complex aerodynamic interference problems, and have repeatedly experienced rollover accidents, with a high crash rate. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that tiltrotor aircraft have poor lateral stability due to complex aerodynamic interference problems, and have suffered repeated rollover accidents and a high crash rate.

[0005] The technical solution of the present invention is to provide a tiltrotor aircraft in which the rotor tilt axis is not orthogonal to the body coordinate plane. First, a non-orthogonal tiltrotor aircraft is provided. The tilt axis 10 at the lower end of the tilt nacelle 4 is tilted. The tilt axis 10 is parallel to the XZ plane, at a 45° angle to the X and Z axes, and is not orthogonal to the XY and YZ planes of the fuselage coordinate system. The positive direction of the X axis is rearward along the heading, the positive direction of the Y axis is rightward along the heading, and the positive direction of the Z axis is vertically upward. This provides lateral stabilization, improving lateral stability and preventing fuselage pitch instability caused by the tilt of the rotor nacelle.

[0006] The aircraft consists of a fuselage 1, wings 2, a fixed nacelle 3, a tilting nacelle 4, a rotor power control assembly 5, a tail wing 6, and a ventral fin 7. The fixed nacelle 3 is provided with a tilting servo 8 and a driven gear 11. The tilting servo 8 is provided with a driving gear 9, which meshes with the driven gear 11. The tilt nacelle 4 is provided with a rotor power control assembly 5, and a tilt shaft 10 is provided at the lower end of the tilt nacelle 4; the tilt nacelle 4 is mounted on the fixed nacelle 3 via the tilt shaft 10, and the fixed nacelle 3 is provided with a shaft hole allowing the tilt shaft 10 to pass through. After passing through the shaft hole, the tilt shaft 10 is fixedly connected to the driven gear 11. The wing 2 is fixed to the middle of the fuselage 1, and the end of the wing 2 is provided with aileron control surfaces. The tail 6 is fixed above the tail of the fuselage 1, and the left and right sides of the tail 6 are provided with pitch and heading control surfaces. The ventral fin 7 is fixed below the tail of the fuselage 1. The fixed nacelles 3 are fixed on the wing tips of the wings 2, and the tilt shafts 10 are installed between the fixed nacelles 3 and the tilt nacelles 4, and the tilt shafts 10 can rotate smoothly in the central holes of the fixed nacelles 3. The tilt process is as follows: the tilt rudder 8 drives the driving gear 9 to rotate, the driving gear 9 drives the driven gear 11 to rotate, the driven gear 11 drives the tilt nacelle 4 to rotate around the tilt shaft 10 through the tilt shaft 10, and the tilt of the rotor power control assembly 5 is realized.

[0007] Because the tilt shaft 10 is arranged obliquely, the tilt nacelle 4 is tilted forward and outward, and presents an "outward eight" posture, and generates a positive dihedral angle and a negative toe angle. When one side of the rotor is in a vortex ring state and the tension is reduced, the aircraft rolls to one side, and the force arm of the rotor on the other side relative to the center of gravity of the aircraft body becomes larger, and a reverse righting moment in the opposite direction is generated, which helps the aircraft to restore to the horizontal state.

[0008] Furthermore, for a small-size tilt rotor aircraft, the total weight of the two tilt nacelles 4 may be comparable to the weight of the fuselage. During the tilt process, due to the law of conservation of angular momentum, it is likely that the nacelles are not tilted and the fuselage is tilted upward, which is very unfavorable for pitch control. The aircraft of the present application uses the obliquely arranged tilt shaft 10 to well offset the counter-torque of the two tilt nacelles 4 on the fuselage, avoiding the problem of unstable pitch control.

[0009] Among them, a small boss is arranged on the driven gear 11, and a top wire hole is arranged on the side surface of the boss, which is used to fix the tilt shaft 10.

[0010] Among them, a flange is arranged at the connection between the end of the tilt shaft 10 and the driven gear 11, which prevents the lift generated by the rotor power control assembly 5 from pulling the tilt nacelle 4 out of the fixed nacelle 3.

[0011] Among them, the rotor power control assembly 5 includes a rotor system, a control system and a power system, the motor of the power system directly drives the main shaft of the rotor system, the control rudder of the control system adopts a 120-degree compact ring embracing layout mode, and the rotor power control assembly 5 adopts a highly integrated design mode, so that the transmission system is cancelled, and the volume and weight are greatly reduced compared with a transmission helicopter.

[0012] Among them, the driving gear 9 and the driven gear 11 are made of high-strength aviation aluminum alloy, which can withstand greater load compared with plastic gears.

[0013] Among them, the fuselage 1 is provided with a through hole along the length direction, and adopts a through design mode, which allows air to directly enter from the nose during high-speed flight, and efficiently cools the avionics, flight control and power supply systems, and then discharges from the tail, which can dissipate heat for the avionics, flight control and power supply systems.

[0014] The tail wing 6 is a V-shaped tail wing, and the tail wing is designed in a V-shaped tail wing design manner, and both pitch and heading control are considered, and the V-shaped tail wing has a lighter weight compared with a traditional horizontal tail wing and vertical tail wing.

[0015] In a second aspect, a flight control method of the non-orthogonal tilt-rotor aircraft is provided, comprising: 1) When the aircraft takes off vertically, the two side tilt-rotor nacelles 4 are vertically upward, and the lift is provided by the rotor power control assembly 5 to maintain the attitude stability of the aircraft; 2) When the aircraft flies forward, the driving gear 9 is rotated by the tilt-rotor actuator 8, the driving gear 9 drives the driven gear 11 to rotate, the driven gear 11 drives the tilt-rotor nacelles 4 to rotate around the tilt-rotor shaft 10 through the tilt-rotor shaft 10, and then the tilt of the rotor power control assembly 5 is realized; 3) During the tilt process, as the speed of the aircraft increases, the wing 2 gradually generates lift and roll control effect, the lift of the aircraft is partly provided by the rotor power control assembly 5, and the wing 2 provides the control moment for the pitch and heading; 4) After the tilt is completed, the two side tilt-rotor nacelles 4 are completely horizontally forward, the forward flight tension of the aircraft is completely provided by the rotor power control assembly 5, the lift is completely provided by the wing 2, the roll control stability control is completely provided by the wing 2, and the pitch and heading control stability control is completely provided by the V-shaped tail wing 6; And the process of vertical landing is completely opposite to the process of 1) ~ 4).

[0016] The application has the following beneficial effects: Since the tilt shaft is arranged obliquely, the tilt-rotor nacelles are tilted forward and outward, and present an "eight" posture, and generate a positive dihedral angle and a negative toe angle. When one side rotor falls into a vortex ring state and the tension decreases, the aircraft rolls to one side, the force arm of the rotor on the other side relative to the center of gravity of the aircraft body becomes larger, and a reverse righting moment is generated to help the aircraft attitude to recover to the horizontal. In addition, for a small-size tilt-rotor aircraft, the total weight of the two side tilt-rotor nacelles may be comparable to the weight of the fuselage. During the tilt process, due to the conservation of angular momentum, it is likely that the nacelles are not tilted and the fuselage is tilted upward, which is very unfavorable for pitch control. The aircraft of the application uses the obliquely arranged tilt shaft to well offset the counter-torque of the two side tilt-rotor nacelles on the fuselage, and avoids the problem of unstable pitch control. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a whole schematic view of the non-orthogonal tilt-rotor aircraft of the application; Figure 2 It is an exploded schematic view of the non-orthogonal tilt-rotor aircraft of the application; Figure 3FIG. 6 is a rear view of a non-orthogonal tilt-rotor aircraft in a vertical take-off and landing state according to the present application; Figure 4 FIG. 7 is a front view of a non-orthogonal tilt-rotor aircraft in a vertical take-off and landing state according to the present application; Figure 5 FIG. 8 is a rear view of a non-orthogonal tilt-rotor aircraft in a tilt transition state according to the present application; Figure 6 FIG. 9 is a front view of a non-orthogonal tilt-rotor aircraft in a tilt transition state according to the present application; Figure 7 FIG. 10 is a rear view of a non-orthogonal tilt-rotor aircraft in a high speed flight state according to the present application; Figure 8 FIG. 11 is a front view of a non-orthogonal tilt-rotor aircraft in a high speed flight state according to the present application. DETAILED DESCRIPTION

[0018] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will describe the technical solutions in the embodiments of the present application with reference to the drawings. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall into the scope of the present application.

[0019] The features and illustrative embodiments of various aspects of the present application will be described below in detail. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one of ordinary skill in the art that the present application can be practiced without some or all of these specific details. The description of the embodiments is merely to provide a better understanding of the present application by showing examples of the present application. The present application is in no way limited to any particular set of details disclosed below, but covers any modifications, equivalents, and alternatives falling within the spirit of the present application. In the drawings and the following description, well-known structures and techniques are not shown in order to avoid unnecessary obscurity of the present application.

[0020] It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict, and each embodiment can be mutually referenced and quoted.

[0021] The present application will be described in detail below with reference to the drawings and specific embodiments.

[0022] The application provides a tilt-rotor aircraft with a non-orthogonal tilt-rotor axis and a tilt-rotor short cabin, the tilt-rotor axis of the tilt-rotor short cabin is arranged obliquely, and the body coordinate system is defined as follows: the positive direction of the X axis is rearward along the heading, the positive direction of the Y axis is rightward along the heading, and the positive direction of the Z axis is upward along the vertical direction; the tilt-rotor axis is parallel to the XZ plane and forms an angle of 45 degrees with the X axis and the Z axis, and is not orthogonal to the XY plane and the YZ plane of the body coordinate system, so it is called a non-orthogonal tilt-rotor axis.

[0023] Referring to Figure 1 and Figure 2 The aircraft is composed of a fuselage 1, a wing 2, a fixed nacelle 3, a tilt-rotor short cabin 4, a rotor power control assembly 5, a V-tail 6 and a ventral fin 7, the fixed nacelle 3 is provided with a tilt-rotor actuator 8 and a driven gear 11, the tilt-rotor actuator 8 is provided with a driving gear 9, the tilt-rotor short cabin 4 is internally provided with the rotor power control assembly 5, and the tilt-rotor short cabin 4 is provided with a tilt-rotor axis 10 at the lower end.

[0024] The wing 2 is fixed in the middle of the fuselage 1, the wing 2 is provided with aileron control surfaces at the ends, the V-tail 6 is fixed above the tail of the fuselage 1, the V-tail 6 is provided with pitch and heading control surfaces on the left and right sides, and the ventral fin 7 is fixed below the tail of the fuselage 1.

[0025] The fixed nacelle 3 is fixed on the wing tips of the wing 2, and there is one on each side, the tilt-rotor short cabin 4 is installed on the fixed nacelle 3 through the tilt-rotor axis 10, the tilt-rotor short cabin 4 is fixedly connected with the tilt-rotor axis 10, the tilt-rotor axis 10 is fixedly connected with the driven gear 11, bearings are installed between the tilt-rotor axis 10 and the fixed nacelle 3, and the tilt-rotor axis 10 can rotate smoothly in the center hole of the fixed nacelle 3.

[0026] The tilt-rotor process is that the tilt-rotor actuator 8 drives the driving gear 9 to rotate, the driving gear 9 drives the driven gear 11 to rotate, the driven gear 11 drives the tilt-rotor short cabin 4 to rotate around the tilt-rotor axis 10 through the tilt-rotor axis 10, and the tilt-rotor process realizes the tilt of the rotor power control assembly 5.

[0027] Since the tilt-rotor axis 10 is arranged obliquely, the tilt-rotor short cabin is tilted forward and outward, and presents an "eight" posture, thereby generating a positive dihedral angle and a negative toe angle. When one side of the rotor is in a vortex ring state and the tension is reduced, the aircraft rolls to one side, the force arm of the rotor on the other side relative to the body center of gravity becomes larger, and a reverse righting moment in the opposite direction is generated, thereby helping the aircraft to restore to the horizontal state.

[0028] Furthermore, for small size tilt-rotor aircraft, the total weight of the two side tilting nacelles can be comparable to the weight of the fuselage. During tilting, due to the conservation of angular momentum, it is likely that the nacelles are not tilted while the fuselage is tilted upward, which is very unfavorable for pitch control. The present aircraft uses an oblique tilting shaft to well offset the counter-torque of the two side tilting nacelles on the fuselage, avoiding the problem of unstable pitch control.

[0029] Further, a small boss is designed on the driven gear 11, and a top screw hole is arranged on the side of the boss, which is used for fixing the tilting shaft 10.

[0030] Further, a turn-up edge is designed at the end of the tilting shaft 10, which prevents the lift generated by the rotor power control assembly 5 from pulling the tilting nacelle 4 out of the fixed nacelle 3.

[0031] Further, the rotor power control assembly 5 adopts a highly integrated design, the motor directly drives the main shaft, and the transmission system is cancelled, and the steering gear adopts a 120-degree compact ring embracing layout, which greatly reduces the volume and weight compared with a transmission helicopter.

[0032] Further, the driving gear 9 and the driven gear 11 are both made of high-strength aviation aluminum alloy, which can withstand greater load compared with plastic gears.

[0033] Further, the fuselage 1 adopts a through design, which allows air to directly enter from the nose during high-speed flight, efficiently cools the avionics and flight control system, and then discharges from the tail.

[0034] Further, the tail wing adopts a V-tail design, which takes into account pitch and heading control, and has a lighter weight compared with traditional horizontal tail and vertical tail.

[0035] An embodiment of the present application also provides a flight control method of a non-orthogonal tilt-rotor aircraft, comprising: 1) When the aircraft takes off vertically, the two side tilting nacelles 4 are vertically upward, and the rotor power control assembly 5 provides lift and maintains the attitude stability of the aircraft; see Figure 3 and Figure 4 , 2) When the aircraft tilts forward, the driving gear 9 is driven to rotate by the tilting steering gear 8, the driving gear 9 drives the driven gear 11 to rotate, the driven gear 11 drives the tilting nacelle 4 to rotate around the tilting shaft 10 through the tilting shaft 10, thereby realizing the tilting of the rotor power control assembly 5; see Figure 5 and Figure 6 , 3) During tilting, as the speed of the aircraft increases, the wing 2 gradually generates lift and roll control effect, and the lift of the aircraft is partially provided by the rotor power control assembly 5 and partially provided by the wing 2, and the V-tail 6 provides stable control for pitch and heading control; 4) After tilting, the two tilting nacelles 4 are completely horizontal forward, the forward flight drag of the aircraft is completely provided by the rotor power steering assembly 5, the lift is completely provided by the wings 2, the roll steering stability control is completely provided by the wings 2, and the pitch and heading steering stability control is completely provided by the V-tail 6; see Figure 7 and Figure 8 , The process of vertical landing is completely opposite to the processes of 1) ~ 4).

[0036] The above only expresses the embodiments of the present application, the description is more specific and detailed, but it cannot be understood as the limitation of the patent scope. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. In addition, the parts of the present application not described in detail are all conventional technologies.

Claims

1. A non-orthogonal tiltrotor aircraft, characterized by, The tilt shaft (10) at the lower end of the tilting nacelle (4) is arranged obliquely, the tilt shaft (10) is parallel to the XZ plane, and is 45° with the X axis and the Z axis, and is not orthogonal to the XY plane and the YZ plane of the body coordinate system; wherein the positive direction of the X axis is along the heading direction to the rear, the positive direction of the Y axis is along the heading direction to the right, and the positive direction of the Z axis is along the vertical direction upward.

2. The non-orthogonal tiltrotor aircraft according to claim 1, characterized in that, The aircraft is composed of a fuselage (1), a wing (2), a fixed nacelle (3), a tilting nacelle (4), a rotor power control assembly (5), a tail (6), and a belly fin (7), The fixed nacelle (3) is provided with a tilting steering engine (8) and a driven gear (11), the tilting steering engine (8) is provided with a driving gear (9), and the driving gear (9) is engaged with the driven gear (11), The tilting nacelle (4) is internally provided with a rotor power control assembly (5), and the lower end of the tilting nacelle (4) is provided with a tilt shaft (10); the tilting nacelle (4) is installed on the fixed nacelle (3) through the tilt shaft (10), the fixed nacelle (3) is provided with a shaft hole allowing the tilt shaft (10) to pass through, and the tilt shaft (10) is fixedly connected with the driven gear (11) after passing through the shaft hole, The wing (2) is fixed in the middle of the fuselage (1), the end of the wing (2) is distributed with aileron control surfaces, the tail (6) is fixed above the tail of the fuselage (1), and the tail (6) is distributed with pitch and heading control surfaces on the left and right sides, and the belly fin (7) is fixed below the tail of the fuselage (1); The fixed nacelle (3) is fixed on the wing tip of the wing (2), one on the left and one on the right, a bearing is installed between the tilt shaft (10) and the fixed nacelle (3), and the tilt shaft (10) can rotate smoothly in the center hole of the fixed nacelle (3); The tilting process is: the tilting steering engine (8) drives the driving gear (9) to rotate, the driving gear (9) drives the driven gear (11) to rotate, the driven gear (11) drives the tilting nacelle (4) to rotate around the tilt shaft (10) through the tilt shaft (10), and the tilting of the rotor power control assembly (5) is realized.

3. The non-orthogonal tiltrotor aircraft according to claim 2, characterized in that, A boss is arranged on the driven gear (11), and a top wire hole is arranged on the side of the boss, which is used to be fixed with the tilt shaft (10).

4. The non-orthogonal tiltrotor aircraft of claim 2, wherein, A flange is arranged at the connection between the end of the tilt shaft (10) and the driven gear (11).

5. The non-orthogonal tiltrotor aircraft according to claim 2, characterized in that, The rotor power control assembly (5) includes a rotor system, a control system and a power system, wherein the motor of the power system directly drives the main shaft of the rotor system, and the control system adopts a 120-degree compact ring embracing layout mode.

6. The non-orthogonal tiltrotor aircraft according to claim 2, characterized in that, The driving gear (9) and the driven gear (11) are both made of high-strength aviation aluminum alloy.

7. The non-orthogonal tiltrotor aircraft according to claim 2, characterized in that, A through hole is arranged along the length direction of the fuselage (1).

8. The non-orthogonal tiltrotor aircraft according to claim 2, characterized in that, The tail (6) is a V-tail.

9. A flight control method of the non-orthogonal tilt-rotor aircraft according to any one of claims 1 to 8, characterized by, The aircraft is composed of a fuselage (1), a wing (2), a fixed nacelle (3), a tilting nacelle (4), a rotor power control assembly (5), a tail (6), and a belly fin (7), When the aircraft takes off vertically, the tilting nacelles on both sides are vertically upward, the rotor power control assembly provides lift and maintains the attitude stability of the aircraft; When the aircraft tilts forward, the tilting steering engine drives the driving gear to rotate, the driving gear drives the driven gear to rotate, the driven gear drives the tilting nacelle to rotate around the tilt shaft, and the tilting of the rotor power control assembly is realized. During the tilting process, as the speed of the aircraft increases, the wings gradually generate lift and roll control effect, the lift of the aircraft is partly provided by the rotor power steering assembly, and the wings, V-tail provide control stability control moment in pitch and heading; After tilting is completed, the two sides of the tilting nacelles are completely horizontal forward, the forward flight pull of the aircraft is completely provided by the rotor power steering assembly, the lift is completely provided by the wings, the roll control stability control is completely provided by the wings, and the pitch and heading control stability control is completely provided by the V-tail. And the process of vertical landing is completely opposite to the above process.

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