A tilt-rotor vertical takeoff and landing aircraft and a rotor angle design method

Abstract

The present invention relates to the field of aircraft design, in particular to a tilt-rotor vertical takeoff and landing aircraft and a rotor angle design method. The tilt-rotor vertical takeoff and landing aircraft includes a fuselage unit, the fuselage unit includes a fuselage and landing gears, and a first angle α1 is formed between the minimum air resistance direction of the fuselage and the bottom plane of the landing gears; a rotor unit, the rotor unit includes a rotor assembly, the rotor assembly includes a bracket, blades and a driver, the blades are rotatably arranged on the bracket, the bracket is connected to the fuselage, the output end of the driver is connected to the blades, and a second angle α2 is formed between the rotation axis of the blades and the minimum air resistance direction, and the sum of the angles of the first angle α1 and the second angle α2 is 90 degrees; a wing unit, the wing unit includes a wing assembly and an attitude adjustment assembly, the attitude adjustment assembly is rotatably connected to the fuselage, and the wing assembly is arranged on the attitude adjustment assembly.

Description

Technical Field

[0001] The present invention relates to the field of aircraft design, and particularly to a tilt-wing vertical takeoff and landing aircraft and a rotor angle design method thereof. Background Art

[0002] Existing aircraft can generally be divided into two categories: heavier-than-air aircraft and lighter-than-air aircraft. Lighter-than-air aircraft, such as balloons, airships, etc., have been eliminated from mainstream aircraft due to many problems such as low safety, high cost, and low flight efficiency. The existing mainstream aircraft mainly achieve flight through fixed-wing, rotor, or a combination of fixed-wing and rotor flight methods.

[0003] In actual use, fixed-wing aircraft can have a relatively high flight speed and are suitable for long-distance high-speed flight. However, fixed-wing aircraft require a long runway for takeoff and landing, are not suitable for operating in narrow spaces, and do not have the functions of vertical takeoff and landing and hovering operations; rotorcraft can achieve vertical takeoff and landing and hovering, are suitable for operating in narrow spaces, but the flight speed of rotorcraft is usually relatively low, not suitable for long-distance high-speed flight, and the fuel efficiency is usually lower than that of fixed-wing aircraft, and the flight endurance is limited; there is also a tilt-rotor aircraft in existing aircraft. This type of aircraft combines the advantages of rotorcraft and fixed-wing aircraft, but the design, manufacturing, and control technologies are difficult, and it is difficult to achieve mass production. Summary of the Invention

[0004] In view of the problems in the above or existing technologies, the present invention is proposed.

[0005] Therefore, the object of the present invention is to provide a tilt-wing vertical takeoff and landing aircraft, which can more effectively utilize aerodynamic force, reduce energy consumption, and increase cruise time compared with traditional multi-rotor aircraft; reduce the volume and lower the requirements for takeoff and landing sites compared with traditional wing aircraft; and reduce the design, manufacturing, and control technology difficulties and costs compared with tilt-rotor aircraft.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: A tilt-rotor vertical takeoff and landing aircraft, which includes a fuselage unit. The fuselage unit includes a fuselage and landing gears. A first angle α1 is formed between the minimum air resistance direction of the fuselage and the bottom plane of the landing gears; a rotor unit, the rotor unit includes a rotor assembly. The rotor assembly includes a bracket, a blade and a driver. The blade is rotatably arranged on the bracket. The bracket is connected to the fuselage. The output end of the driver is connected to the blade. A second angle α2 is formed between the rotation axis of the blade and the minimum air resistance direction. The sum of the angles of the first angle α1 and the second angle α2 is 90 degrees; a wing unit, the wing unit includes a wing assembly and an attitude adjustment assembly. The attitude adjustment assembly is rotatably connected to the fuselage. The wing assembly is arranged on the attitude adjustment assembly.

[0007] As a preferred solution of the tilt-rotor vertical takeoff and landing aircraft of the present invention, wherein: The number of the wing assemblies is two groups. The wing assemblies are symmetrically arranged on both sides of the fuselage. An angle of attack α3 is formed between the axis of the wing assembly and the fuselage. The angle of attack α3 is actively adjusted by the attitude adjustment assembly.

[0008] As a preferred solution of the tilt-rotor vertical takeoff and landing aircraft of the present invention, wherein: The rotor assembly is not less than four groups. The rotor assemblies are circumferentially and uniformly arranged around the fuselage, and the heights can be the same or different.

[0009] As a preferred solution of the tilt-rotor vertical takeoff and landing aircraft of the present invention, wherein: The fuselage unit further includes an energy module and a control module. The energy module is used to provide energy. The control module is electrically connected to the rotor unit and the wing unit.

[0010] As a preferred solution of the tilt-rotor vertical takeoff and landing aircraft of the present invention, wherein: The control module includes a sensor and a navigator. The sensor can sense the external environment. The navigator can perform positioning and navigation.

[0011] As a preferred solution of the tilt-rotor vertical takeoff and landing aircraft of the present invention, wherein: The energy module includes a fuel cell and a storage battery.

[0012] Another object of the present invention is to provide a rotor angle design method, which can further improve the cruising time of the tilt-rotor vertical takeoff and landing aircraft.

[0013] To solve the above technical problems, the present invention provides the following technical solutions: A rotor angle design method, which includes determining a critical speed v at which the wing assembly is converted from the maximum lift coefficient state to the non-maximum lift coefficient state through the parameters of the wing assembly. convert; Distinguish the flight state of the tilt-rotor wing vertical takeoff and landing aircraft and the required power P during flight through the parameters of the wing assembly and the parameters of the rotor assembly prop ; Determine the forward tilt angle θ through the cruising speed v cruise and then determine the magnitudes of the first included angle α1 and the second included angle α2 through the forward tilt angle θ.

[0014] As a preferred scheme of the rotor angle design method described in the present invention, wherein: the critical speed v at which the wing assembly is converted from the maximum lift coefficient state to the non-maximum lift coefficient state convert The calculation formula is:

[0015]

[0016] Where v convert is the critical speed at which the wing assembly is converted from the maximum lift coefficient state to the non-maximum lift coefficient state, W is the weight of the tilt-rotor wing vertical takeoff and landing aircraft, g is the acceleration due to gravity, C L is the lift coefficient of the wing assembly, A wing is the projected area of the wing assembly in the XY plane of the body coordinate system, ρ air is the air density.

[0017] As a preferred scheme of the rotor angle design method described in the present invention, wherein: when the flight speed v ≤ v convert The force balance equation in the horizontal direction is

[0018]

[0019] The force balance equation in the vertical direction:

[0020]

[0021] From the above two equations, T prop (v) and θ(v) can be solved, and θ max = π / 2

[0022] Where C D is the overall drag coefficient of the aircraft, A body is the projected area of the overall aircraft in the YZ plane of the body coordinate system, v is the flight speed, T prop is the pulling force generated by the rotor assembly, and θ is the forward tilt angle of the overall aircraft;

[0023] This tilt-rotor wing VTOL mainly operates under the condition of v ≤ v convert because θ max needs to be less than π / 2 to ensure rideability;

[0024] At the cruising speed v cruise it is necessary to ensure that θ = the first included angle α1 to ensure the cruising speed vcruise The flight direction of the tilt-rotor wing vertical takeoff and landing aircraft is consistent with the direction of the minimum air resistance.

[0025] As a preferred embodiment of the rotor angle design method of the present invention, where: when the flight speed v > v convert :

[0026] θ = π / 2

[0027]

[0028] C D2 = C D - K2(C L - C L2 ) 2

[0029]

[0030] Finally, the power of the tilt-rotor wing vertical takeoff and landing aircraft is calculated:

[0031] P prop = k T2P T prop 3 / 2 .

[0032] The beneficial effects of the present invention are as follows: An tilt-rotor wing vertical takeoff and landing aircraft and a rotor angle design method thereof according to the present invention can effectively utilize aerodynamic force, reduce energy consumption, increase cruise time, reduce the volume compared with traditional wing aircraft, reduce the requirements for takeoff and landing sites, reduce the design, manufacturing and control technical difficulties compared with tilt-rotor aircraft, and reduce costs; The cruise time of the tilt-rotor wing vertical takeoff and landing aircraft can be further improved through the rotor angle design method. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. Among them:

[0034] Figure 1 is a schematic diagram of the overall structure of the tilt-rotor wing vertical takeoff and landing aircraft;

[0035] Figure 2 is the first side view of the tilt-rotor wing vertical takeoff and landing aircraft;

[0036] Figure 3 is the second side view of the tilt-rotor wing vertical takeoff and landing aircraft;

[0037] Figure 4 System diagram of a tilt-wing vertical takeoff and landing aircraft;

[0038] Figure 5 Flight efficiency comparison chart;

[0039] Figure 6 Angle selection chart for the first included angle. Detailed implementation manners

[0040] To make the above objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the specific implementation manners of the present invention will be given with reference to the accompanying drawings of the specification.

[0041] In the following description, many specific details are set forth to facilitate a thorough understanding of the present invention. However, the present invention may be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0042] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure or characteristic that may be included in at least one implementation manner of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is separate or selectively exclusive of other embodiments.

[0043] Embodiment 1

[0044] Referring to Figures 1 to 4 , this is the first embodiment of the present invention. This embodiment provides a tilt-wing vertical takeoff and landing aircraft, which specifically includes a fuselage unit 100. The fuselage unit 100 includes a fuselage 101 and landing gears 102. A first included angle α1 is formed between the minimum air resistance direction 101a of the fuselage 101 and the bottom plane of the landing gears 102; a rotor unit 200, the rotor unit 200 includes a rotor assembly 201. The rotor assembly 201 includes a bracket 201a, blades 201b and a driver 201c. The blades 201b are rotatably arranged on the bracket 201a. The bracket 201a is connected to the fuselage 101. The output end of the driver 201c is connected to the blades 201b. A second included angle α2 is formed between the rotation axis of the blades 201b and the minimum air resistance direction 101a. The sum of the angles of the first included angle α1 and the second included angle α2 is 90 degrees; a wing unit 300, the wing unit 300 includes a wing assembly 301 and an attitude adjustment assembly 302. The attitude adjustment assembly 302 is rotatably connected to the fuselage 101. The wing assembly 301 is arranged on the attitude adjustment assembly 302.

[0045] Furthermore, the number of wing assemblies 301 is two groups, and the wing assemblies 301 are symmetrically arranged on both sides of the fuselage 101. The angle of attack α3 formed by the wing assemblies 301 and the axis of the fuselage 101 is actively adjusted by the attitude adjustment assembly 302.

[0046] It should be noted that the value range of the angle of attack α3 is (-20° - 20°), and within this range, it is more in line with the C_L–alpha (lift coefficient - angle of attack) curve of the wing.

[0047] Furthermore, the number of rotor assemblies 201 is not less than four groups, and the rotor assemblies 201 are evenly distributed circumferentially around the fuselage 101, and the heights can be the same or different.

[0048] Preferably, the airframe unit 100 further includes an energy module 103 and a control module 104. The energy module 103 is used to provide energy, and the control module 104 is electrically connected to the rotor unit 200 and the wing unit 300; the control module 104 includes a sensor 104a and a navigator 104b. The sensor 104a can sense the external environment, and the navigator 104b can perform positioning and navigation; the energy module 103 includes a fuel cell 103a and a storage battery 103b.

[0049] In this embodiment, when the tilt-rotor vertical takeoff and landing aircraft takes off, the rotor assembly 201 provides lift away from the ground, and the angle of attack α3 can be appropriately adjusted to reduce the rising resistance, enabling vertical lift; after reaching a certain height, the fuselage 101 of the tilt-rotor vertical takeoff and landing aircraft rotates at a certain angle to meet the requirements of aerodynamic force in the flight direction (the forward direction of the airframe is the same as the designed minimum air resistance direction 101a), and the wing assembly 301 also makes a corresponding rotation to provide appropriate (neither too large nor too small) lift during cruising. After that, it enters the cruising mode. At this time, the forward direction of the airframe is the same as the designed minimum air resistance direction 101a, and the rotor assembly 201 provides the driving force for forward movement and a certain amount of lift;

[0050] It should be noted that when preparing to land at the end of the cruising mode, the tilt-rotor vertical takeoff and landing aircraft rotates again to make the landing gear 102 parallel to the ground, and lands under the adjustment of the rotor assembly 201. At this time, the wing assembly 301 can be appropriately rotated to change the angle of attack α3 to provide descending resistance and slow down the landing speed, and finally vertical landing can be achieved.

[0051] Embodiment 2

[0052] Refer to Figures 1 to 6 , for the second embodiment of the present invention, this embodiment provides a rotor angle design method, which includes determining the critical speed v at which the wing assembly 301 transitions from the maximum lift coefficient state to the non-maximum lift coefficient state based on the parameters of the wing assembly 301 convert ;

[0053] Distinguish the flight state of the tilt-rotor vertical takeoff and landing aircraft and the required power P during flight through the parameters of the wing assembly 301 and the parameters of the rotor assembly 201 prop ;

[0054] Determine the forward tilt angle θ through the cruise speed v cruise and then determine the magnitudes of the first included angle α1 and the second included angle α2 through the forward tilt angle θ.

[0055] Specifically, the critical speed v at which the wing assembly 301 transitions from the maximum lift coefficient state to the non-maximum lift coefficient state convert has the following calculation formula:

[0056]

[0057] where v convert is the critical speed at which the wing assembly 301 transitions from the maximum lift coefficient state to the non-maximum lift coefficient state, W is the weight of the tilt-rotor vertical takeoff and landing aircraft, g is the acceleration due to gravity, C L is the lift coefficient of the wing assembly 301, A wing is the projected area of the wing assembly 301 in the XY plane of the body coordinate system, and ρ air is the air density.

[0058] Furthermore, when the flight speed v ≤ v convert , the force balance equation in the horizontal direction is

[0059]

[0060] The force balance equation in the vertical direction:

[0061]

[0062] From the above two equations, T prop (v) and θ(v) can be solved, and θ max = π / 2

[0063] where C D is the overall drag coefficient of the aircraft, A body is the projected area of the overall aircraft in the YZ plane of the body coordinate system, v is the flight speed, T prop is the pulling force generated by the rotor assembly 201, and θ is the forward tilt angle of the overall aircraft;

[0064] This tilt-rotor VTOL mainly operates in the case of v ≤ v convert because θ max needs to be less than π / 2 to ensure rideability;

[0065] At the cruise speed v cruiseUnder this condition, it is necessary to ensure that the forward tilt angle θ of the whole machine is equal to the first included angle α1 to ensure the cruising speed v cruise The flight direction of the tilt-rotor wing vertical takeoff and landing aircraft is consistent with the minimum air resistance direction 101a.

[0066] Furthermore, when the flight speed v > v convert :

[0067] θ = π / 2

[0068]

[0069] C D2 = C D - K2(C L - C L2 ) 2

[0070]

[0071] Finally, the power of the tilt-rotor wing vertical takeoff and landing aircraft is calculated:

[0072] P prop = k T2P T prop 3 / 2

[0073] Finally, the P prop —v image ( Figure 5 the blue line in).

[0074] Preferably, the multi-rotor power calculation method:

[0075] Horizontal force balance:

[0076]

[0077] Vertical force balance:

[0078] T prop cosθ = Wg

[0079] Solve for T prop (v) and then perform power calculation:

[0080] P prop = K T2P T prop 3 / 2

[0081] The P prop —ν image ( Figure 5 the red line in).

[0082] From Figure 5It can be seen that the tilt-rotor vertical takeoff and landing aircraft saves about 70% of the power compared with the multi-rotor aircraft.

[0083] In addition, according to θ(ν) in the above formula, the curve as shown in Figure 6 is obtained. The first included angle α1 is determined according to the designed cruise speed v cruise (for example, when the designed cruise speed v cruise is 30.1003 m / s, the recommended designed angle of the first included angle α1 is 16.2055°).

[0084] It should be understood that during the development of any actual implementation, such as in any engineering or design project, a large number of specific implementation decisions can be made. Such development efforts may be complex and time-consuming, but for those of ordinary skill in the art who benefit from this disclosure, without undue experimentation, the development efforts will be routine work of design, manufacture, and production.

[0085] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A tilt-wing vertical takeoff and landing aircraft, characterized in that: including a body unit (100), the body unit (100) includes a fuselage (101) and landing gears (102), and a first included angle (α1) is formed between the minimum air resistance direction (101a) of the fuselage (101) and the bottom plane of the landing gears (102); Rotor unit (200), the rotor unit (200) includes a rotor assembly (201), the rotor assembly (201) includes a bracket (201a), a blade (201b) and a driver (201c), the blade (201b) is rotatably arranged on the bracket (201a), the bracket (201a) is connected to the fuselage (101), the output end of the driver (201c) is connected to the blade (201b), and a second angle (α2) is formed between the rotation axis of the blade (201b) and the minimum air resistance direction (101a). The sum of the angles of the first angle (α1) and the second angle (α2) is 90 degrees, wherein the magnitudes of the first angle (α1) and the second angle (α2) are determined by the forward tilt angle θ, and the forward tilt angle θ is determined by the cruising speed v cruise to determine; a wing unit (300), the wing unit (300) includes a wing assembly (301) and an attitude adjustment assembly (302), the attitude adjustment assembly (302) is rotatably connected to the fuselage (101), and the wing assembly (301) is arranged on the attitude adjustment assembly (302); Among them, the critical speed v at which the wing assembly (301) transitions from the maximum lift coefficient state to the non-maximum lift coefficient state convert is calculated by the formula: where v convert is the critical speed at which the wing assembly (301) transitions from the maximum lift coefficient state to a non-maximum lift coefficient, W is the weight of the tilt-rotor vertical takeoff and landing aircraft, g is the acceleration due to gravity, C L is the lift coefficient of the wing assembly (301), A wing is the projected area of the wing assembly (301) in the XY plane of the body coordinate system, ρ air is the air density; Flight states of a tilt-wing vertical takeoff and landing aircraft and power P required during flight prop Distinguished by the parameters of the wing assembly (301) and the parameters of the rotor assembly (201).

2. The tilt-rotor wing vertical takeoff and landing aircraft according to claim 1, wherein: the number of the wing assemblies (301) is two groups, the wing assemblies (301) are symmetrically arranged on both sides of the fuselage (101), and an angle of attack (α3) formed by the wing assemblies (301) and the axis of the fuselage (101) is actively adjusted by the attitude adjustment assembly (302).

3. The tilt-rotor wing vertical takeoff and landing aircraft according to claim 2, characterized in that: The rotor assembly (201) has no less than four groups, and the rotor assemblies (201) are circumferentially and evenly arranged around the fuselage (101), and their heights can be the same or different.

4. The tilt-rotor wing vertical takeoff and landing aircraft according to claim 3, characterized in that: The body unit (100) further includes an energy module (103) and a control module (104), the energy module (103) is used to provide energy, and the control module (104) is electrically connected to the rotor unit (200) and the wing unit (300).

5. The tilt-rotor wing vertical takeoff and landing aircraft according to claim 4, characterized in that: The control module (104) includes a sensor (104a) and a navigator (104b), the sensor (104a) can sense the external environment, and the navigator (104b) can perform positioning and navigation.

6. The tilt-rotor wing vertical takeoff and landing aircraft according to claim 5, characterized in that: The energy module (103) includes a fuel cell (103a) and a storage battery (103b).

7. A rotor angle design method, characterized in that: including the tilt-rotor vertical takeoff and landing aircraft according to any one of claims 1 to 6, which includes Determine the critical speed v at which the wing assembly (301) transitions from the maximum lift coefficient state to the non-maximum lift coefficient state based on the parameters of the wing assembly (301). convert ; Distinguish the flight state of the tilt-rotor vertical takeoff and landing aircraft and the required power P during flight based on the parameters of the wing assembly (301) and the parameters of the rotor assembly (201). prop ; Determine the forward tilt angle θ based on the cruising speed v cruise and then determine the magnitudes of the first included angle (α1) and the second included angle (α2) based on the forward tilt angle θ; The critical speed v at which the wing assembly (301) transitions from the maximum lift coefficient state to the non-maximum lift coefficient state convert is calculated by the formula: where v convert is the critical speed at which the wing assembly (301) transitions from the maximum lift coefficient state to a non-maximum lift coefficient, W is the weight of the tilt-rotor vertical takeoff and landing aircraft, g is the acceleration due to gravity, C L is the lift coefficient of the wing assembly (301), A wing is the projected area of the wing assembly (301) in the XY plane of the body coordinate system, ρ air is the air density.

8. The rotor angle design method according to claim 7, characterized in that: When the flight speed v ≤ v convert , the force balance equation in the horizontal direction is the vertical force balance equation: T can be solved from the above two equations prop (v) and θ(v), and θ max = π / 2 Among them, C D is the overall drag coefficient, A body is the projected area of the whole machine on the YZ plane of the body coordinate system, v is the flight speed, T prop is the pulling force generated by the rotor assembly (201), and θ is the forward tilt angle of the whole machine; This tilting-wing VTOL mainly operates when v ≤ v convert because θ max needs to be less than π / 2 (to ensure ride comfort; At the cruise speed v cruise it is necessary to ensure that θ = the first included angle (α1) to ensure that the flight direction of the tilt-rotor wing vertical take-off and landing aircraft is consistent with the minimum air resistance direction (101a) at the cruise speed v cruise ​ 9. The rotor angle design method according to claim 8, characterized in that: When the flight speed v > v convert : θ = π / 2 C D2 = C D - K2(C L - C L2 ) 2 Finally, the power of the tilt-rotor vertical takeoff and landing aircraft is calculated: P prop = k T2P T prop 3 / 2 .

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