JP2003220999A - Compound rotary-wing aircraft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize high speed and noise reduction of a compound rotary-wing aircraft by reducing BVI noise generated during predetermined descending flight. <P>SOLUTION: In a compound rotary-wing aircraft having a fixed wing 40 to generate lift and a propulsion means 60 provided on a body 10 besides a rotary wing 20 to generate an advance thrust, a resistance increasing means 50 to increase the resistance acting on the body and a control means 90 to control the resistance increase means 50 and the propulsion means 60 depending on an advancing speed and a sinking rate of the body are provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite rotorcraft, and more particularly to a composite rotorcraft capable of reducing BVI noise generated during a predetermined descent flight.

[0002]

2. Description of the Related Art Conventionally, rotary wing aircraft have been used in various fields such as transportation of goods, lifesaving and national defense. Since this rotary wing aircraft flies by generating lift and thrust by the rotary wing, it has a characteristic that the maximum speed is lower than that of a fixed wing aircraft.

Therefore, in order to increase the maximum speed of a rotary wing aircraft, a rotary wing aircraft equipped with fixed wing and a propulsion device, that is, a "compound" rotary wing aircraft has been proposed, and its flight is proposed. Has been realized. This composite rotary-wing aircraft has a maximum maximum speed as compared with a normal rotary-wing aircraft because the lift of the rotary blade can be partly loaded on the fixed wing and the propulsion force can be obtained by the propulsion device. In recent years, a composite rotary wing aircraft 100 having a configuration as shown in FIG. 15 has been proposed (US Pat. No. 5).
No. 738301).

On the other hand, when the rotary-wing aircraft lands, as shown in FIG. 16, the tip vortex V flowing out from the tip of the preceding rotary blade B1 interferes with the following rotary blade B2. This causes noise. This noise is
It is called "BVI (Blade Vortex Interaction) noise" and is one of the factors that prevent an increase in the operation of rotorcraft.

In order to suppress the generation of this BVI noise,
For example, a rotorcraft 200 described in US Pat. No. 5,437,419 has been proposed (see FIG. 17). In the rotary wing aircraft 200, under a flight condition in which BVI noise is generated, the resistance plate 220 provided on the side portion of the fuselage 210 is opened to incline the rotary wing surface and suppress the generation of BVI noise. .

[0006]

When the compound rotorcraft 100 as shown in FIG. 15 is adopted, the maximum speed becomes higher than that of a normal rotorcraft, but at the time of low speed flight such as landing. BVI noise is still generated.

On the other hand, the rotorcraft 200 shown in FIG.
BVI noise can be reduced by adopting, but since the resistance plate 220 is provided on the side portion of the fuselage 210, it may not be suitable for the structure of the composite rotorcraft, and the speedup should be achieved. Was difficult.

An object of the present invention is to achieve both high speed and low noise in a compound rotorcraft by reducing BVI noise generated during a predetermined descent flight.

[0009]

In order to solve the above problems, the invention according to claim 1 is, for example, as shown in FIG. 1, a fixed blade for generating lift and a rotary blade for generating forward thrust. In a composite rotary wing aircraft having a propulsion means provided separately from the fuselage, a resistance increasing means for increasing resistance acting on the airframe, and the resistance increasing means and the propulsion according to a forward speed and a descent rate of the airframe. Control means for controlling the means.

According to the first aspect of the present invention, the compound rotary wing aircraft has the fixed wing for generating the lift force and the propulsion means provided on the fuselage separately from the rotary wing for generating the forward thrust. It is possible to load a part of the lift of the rotary blade on the fixed blade and obtain the propulsion force by the propulsion means. Therefore, the maximum speed is significantly higher than that of a normal rotary-wing aircraft.

According to the first aspect of the present invention, the resistance increasing means for increasing the resistance acting on the airframe, and the control means for controlling the resistance increasing means and the propulsion means according to the forward speed and the descent rate of the airframe. To provide, for example, BVI
In a descent flight condition where noise is generated, the resistance acting on the aircraft is increased or decreased by the control means,
The rotor surface can be inclined forward or backward.
Therefore, it is possible to separate the blade tip vortex flowing out from the preceding rotary blade and the subsequent rotary blade, and it is possible to suppress the generation of BVI noise.

Therefore, the maximum speed is higher than that of an ordinary rotary wing aircraft, and high-speed flight can be realized.
It is possible to suppress the generation of BVI noise and achieve low noise. That is, high speed and low noise can be achieved at the same time.

According to a second aspect of the present invention, there is provided a composite rotorcraft according to the first aspect, for example, as shown in FIG.
The control means controls the forward speed and the descent rate of the airframe to be BVI.
When in the noise generation region, the rotor surface is inclined forward by increasing the resistance acting on the airframe by controlling the resistance increasing means in a slow descent flight region where the descent rate of the airframe is relatively small. In the steep descent flight region where the descent rate is relatively large, the propulsion means is controlled to increase the forward thrust force acting on the airframe, whereby the rotor blade surface is inclined rearward.

According to the second aspect of the present invention, when the forward speed and the descent rate of the airframe are in the BVI noise generation region, the control means operates the resistance increasing means in the slow descent flight region where the descent rate of the airframe is relatively small. The forward thrust that acts on the fuselage is controlled by controlling the propulsion means in the steep descent flight region where the descent rate of the fuselage is relatively large while controlling the resistance to increase the resistance acting on the fuselage and inclining the rotor surface forward. Since the rotor blade surface is increased and the rotor blade surface is inclined rearward, different control operations are performed in the slow descent flight region and the steep descent flight region, and the generation of BVI noise can be effectively suppressed.

That is, in the "slow descent flight area", the resistance increasing means is controlled by the control means to increase the resistance acting on the airframe and the rotor blade surface is inclined forward, so that Since the outflowing tip vortices will pass "below" the following rotor blades, interference between these blade vortices and the following rotor blades can be avoided, and the generation of BVI noise can be suppressed. it can. Further, in the "descent flight region", the control means controls the propulsion means to increase the forward thrust acting on the airframe to incline the rotor blade surface rearward, so that the blade tip flowing out from the preceding rotor blade is advanced. Since the vortex will pass “above” the following rotor blade, interference between these blade vortices and the following rotor blade can be avoided, and the generation of BVI noise can be suppressed.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the compound rotorcraft described, for example, as shown in FIG. 1, the fixed wing is provided with a movable wing on a trailing edge side thereof, and the resistance increasing means is the movable wing.

According to the third aspect of the present invention, the movable blade provided on the trailing edge side of the fixed blade can function not only as a flap or a spoiler but also as a resistance increasing means. Therefore, it is not necessary to separately provide resistance increasing means.

The invention according to claim 4 is the invention according to claim 1 or 2.
In the composite rotary wing aircraft described above, for example, as shown in FIG. 11, the fixed wing has a variable attachment angle, and the resistance increasing means is the fixed wing.

According to the fourth aspect of the invention, since the mounting angle of the fixed blade is variable, the fixed blade itself can function as the resistance increasing means. Therefore, it is not necessary to separately provide resistance increasing means.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, the structure of a composite rotary-wing aircraft according to the present invention and a BVI using this composite rotary-wing aircraft.
The noise suppression control operation will be described.

First, the structure of the composite rotorcraft according to the present embodiment will be described. The compound rotorcraft is shown in Figure 1.
As shown in (a), the body 10, the main rotor 20, the anti-torque control vane 30, the fixed blade 40, the flap 50, the auxiliary propulsion fan 60, the speedometer 70, the speedometer 80, and
A control computer 90 is provided, and in addition to the main rotor 20, a fixed wing 40 that generates lift and an auxiliary propulsion fan 60 that obtains thrust for forward movement are provided, so that a low-speed flight is performed normally. It can function as a rotary-wing aircraft and achieve a maximum speed close to that of a fixed-wing aircraft.

The main rotor 20 has a function of generating lift and thrust, and is driven by the engine 22 via the transmission 21. The structure of the main rotor 20 is not particularly limited as long as it is adopted in an ordinary single rotor type rotor aircraft. Further, the type and number of the engines 22 can be appropriately determined according to the scale of the composite rotorcraft.

The anti-torque control vane 30 is shown in FIG.
As shown in (3), it is composed of three airfoil members rotatably attached to the rear tip portion of the tail boom 11 behind the body 10. This anti-torque control vane 3
0 serves to change the direction of the high-speed gas flowing through the passage in the tail boom 11 to cancel the torque of the main rotor 20 to control yaw motion of the airframe.

The fixed blade 40 contributes to an increase in the maximum speed together with an auxiliary propulsion fan 60, which will be described later, by generating a lift and bearing a part of the lift of the main rotor 20. In the form, it is provided on the lower side of the body 10. The size of this fixed wing 40, airfoil,
The position and the like to be provided can be appropriately determined according to the scale and shape of the composite rotorcraft.

The flap 50 suppresses the reduction in the lift force during low speed flight and hovering, and also functions as a "resistance increasing means" used in the BVI noise suppression control operation described later. Flap 50
Is rotatably attached to the center of the fixed wing 40 via a rotation shaft, and as shown by the dotted line in FIG. 1A, up to 90 ° with respect to the chord line of the fixed wing 40. It is designed to rotate.

The auxiliary propulsion fan 60 is a propulsion means that contributes to an increase in the maximum speed together with the fixed blade 40 by generating thrust for forward movement, and includes a fan drive drive shaft 61 and a fan drive transmission 62. It is driven by the engine 22 via. An air intake 63 is provided in front of the auxiliary propulsion fan 60.

The speedometer 70 detects the forward speed of the machine body, and the lift 80 detects the rising rate or the descending rate of the machine body. In addition, the control computer 90
Is the flap 5 depending on the forward speed of the aircraft detected by the speedometer 70 and the descent rate of the aircraft detected by the elevator 80.
0 and the auxiliary propulsion fan 60 are controlled.

Next, the BVI noise suppression control operation using the compound rotorcraft according to the present embodiment will be described.

First, prior to the description of the specific control operation of the composite rotorcraft according to the present embodiment, FIGS.
The principle of generation of BVI noise will be described using.

The BVI noise is generally caused by a tip end vortex generated from the tip of the preceding rotor blade and the following rotor blade interfering with each other, resulting in a sudden pressure fluctuation on the surface of the following rotor blade. It occurs when it happens. FIG. 2 shows the locus of the tip vortex V generated from the tip of the preceding rotor blade, and the position where this tip vortex V interferes with the following rotor blade (hereinafter referred to as “tip vortex interference position”). ) 1 to 7 as seen from above the main rotor. The main noise source is Fig. 2
Generated at the tip vortex interference positions 2, 3 and 4 shown in Fig.
It is known to be I noise.

FIG. 3 shows the locus of the blade tip vortex V shown in FIG.
It is viewed from the side of the main rotor, (a) shows the trajectory of the tip vortex V during horizontal flight, and (b) shows the trajectory of the tip vortex V when descending at a predetermined descent rate. , (C) is the trajectory of the wing tip vortex V when descending at a descent rate higher than that of (b),
Shown respectively.

During horizontal flight, the rotor blade surface is inclined forward to generate thrust by the main rotor, whereas the direction of uniform flow is horizontal. Therefore, FIG.
As shown in (a), the blade tip vortex V generated from the tip of the preceding rotor blade B1 flows horizontally along with this uniform flow, and therefore passes below the following rotor blade B2.
As a result, the blade tip vortex V and the following rotor blade B2 do not interfere with each other, so that BVI noise is not generated.

On the other hand, during descent flight, in addition to the rotor blade surface being inclined forward in order to generate thrust by the main rotor blade, the uniform flow makes a constant angle with the horizontal direction. This is the case (see FIGS. 3B and 3C).

Therefore, when descending at a predetermined descent rate such that the angle formed by the rotor blade surface with the horizontal direction and the angle formed by the uniform flow with the horizontal direction are close to each other (see FIG. 3 (b)). B, the blade tip vortex V generated from the tip of the preceding rotor blade B1 interferes with the rotor blade B2 that follows, so that BVI noise is generated.

On the other hand, as shown in FIG.
When descending at a descent rate higher than that shown in (b), the angle formed by the uniform flow with the horizontal direction is larger than the angle formed by the rotor blade surface with the horizontal direction. Therefore, as shown in FIG.
The tip vortex V generated from the tip of No. 1 passes above the following rotary vane B2. As a result, the blade tip vortex V and the following rotor blade B2 do not interfere with each other, so that BVI noise is not generated.

In FIG. 4, the horizontal axis indicates the forward speed (kt) of the airframe.
Is a distribution diagram showing the region where BVI noise is generated, with the vertical axis representing the ascending / descending rate (ft / min). As shown in FIG. 4, at a forward speed of the airframe of about 40 to about 100 kt, a hoisting rate of about -600 to about 0 ft / min (that is, a descent rate of about 0).
It can be seen that relatively large BVI noise is generated in the flight region of about 600 ft / min).

As described above, the BVI noise suppression control operation using the composite rotary wing aircraft according to the present embodiment is performed as described above.
Noise is in a specific flight area (forward speed about 40 to about 100k
t, descent rate about 0 to about 600 ft / min flight area: This flight area is referred to as "BVI noise generation area").

That is, in the BVI noise generation region, the rotor blade surface of the main rotor 20 is positively inclined forward or backward, whereby the rotor blades following the blade tip vortex generated from the tip of the preceding rotor blade are followed. By passing below or above the blade, interference between the tip vortex and the following rotor blade is avoided, and the generation of BVI noise is suppressed.

Here, in the BVI noise suppression control operation using the composite rotorcraft according to the present embodiment, the rotor blade surface of the main rotor 20 is moved forward or backward by increasing or decreasing the resistance acting on the airframe. Although tilted backward, this principle will be described with reference to FIG.

This principle is derived from the equation of the balance of forces in the longitudinal direction of the machine body. FIG. 5 shows the forces acting on the airframe, where T is the thrust generated by the main rotor 20, W is the gravity acting on the airframe, and H is the main rotor 2.
The aerodynamic force acting in parallel to the rotor blade surface of 0 and Df the resistance acting on the airframe, respectively. In FIG. 5, γ is the angle that the uniform flow makes with the horizontal direction (hereinafter referred to as “flying direction angle”), and α _TPP is the angle that the rotor blade makes with the uniform flow (hereinafter, “rotor attack angle”). , Respectively) are shown. Here, the upward direction of both γ and α _TPP is “positive”. That is, γ shown in FIG. 5 is “positive”, α _TPP
Is "negative".

As shown in FIG. 5, when the X axis parallel to the uniform flow is taken, the balance of forces in the X axis direction is expressed by the following equation. In the following equation, the forward thrust force of the auxiliary propulsion fan 60 is included in the resistance “Df”.

[Equation 1]

Here, in order to simplify the equation, the following approximation is performed.

[Equation 2]

By using these approximate expressions of (2), the expression (1) is simplified as follows.

[Equation 3]

It is clear from the equation (3) that when the resistance Df acting on the airframe is increased, the rotor attack angle α _TPP is increased in the negative direction (downward), and the main rotor 20 is inclined forward. Becomes When the resistance Df acting on the airframe is reduced, the rotor attack angle α _{TP P} becomes positive (upward).
It becomes clear that the main rotor 20 tilts rearward.

Next, a specific control operation using the composite rotorcraft according to this embodiment will be described.

<Control Operation Related to Slow-Descent Flight Region> First,
Of the BVI noise generation area, the descent rate is about 0 to about 300 ft / m
The control operation related to the in flight area (above and below, referred to as “slow descent flight area”) will be described. In the control operation related to the slow descent flight region, the rotor blade surface is positively inclined forward so that the tip vortex generated from the tip of the preceding rotor blade passes “below” the rotor blade that follows. By positively creating such a state (see FIG. 3A), the generation of BVI noise is suppressed.

More specifically, the forward speed of the machine detected by the speedometer 70 is within the range of about 40 to about 100 kt, and the descent rate of the machine detected by the lift 80 is about 0. When it is within the range of about 300 ft / min, the control computer 90 rotates the flap 50 attached to the trailing edge side of the fixed blade 40 so that the angle of the flap 50 with respect to the chord line of the fixed blade 40. To set 90 ° (see FIG. 1) to increase the resistance Df acting on the airframe.

When the resistance Df acting on the airframe increases, the rotor attack angle α _TPP increases in the negative direction (downward) according to the above-described equation (2), and the main rotor 20 tilts forward. Therefore, the tip vortex generated from the tip of the preceding rotor blade passes below the following rotor blade. As a result, it is possible to avoid the interference between the blade tip vortex and the following rotary blade, so that it is possible to suppress the generation of BVI noise.

FIG. 6 shows the relationship between the angle of the flap 50 and the forward speed of the airframe in this slow descent flight region, and the thrust (weight ratio) of the auxiliary propulsion fan 60, which is a propulsion means, and the forward speed of the airframe. It shows the relationship. This Figure 6
As shown in Fig. 4, when the forward speed of the airframe is in the range of 0 to 40 kt, the flap 50 is set to 90 ° so as not to obstruct the flow of the downwind flow created by the main rotor 20. The efficiency can be improved.

Conventionally, as shown by the dotted line in FIG. 6, when the forward speed of the airframe exceeds 40 kt, the angle of the flap 50 is gradually returned from 90 ° to 0 °, but in the present embodiment, Flap 50 even if the forward speed of the vehicle exceeds 40 kt
Is maintained at 90 ° to function as a resistance increasing means. By maintaining the angle of the flap 50 at 90 ° in the BVI noise generation region where the forward speed of the airframe is 40 to 100 kt, the resistance Df acting on the airframe can be increased, and the main rotor 20 is inclined forward. , BVI noise can be suppressed.

On the other hand, as shown in FIG. 6, the forward speed of the machine body is increased as the thrust (weight ratio) by the auxiliary propulsion fan 60, which is the propulsion means, is increased.

Next, the BVI noise suppression control operation relating to the slow descent flight region will be described with reference to FIG. 7, which is a graph of the equation (2).

In the slow descent flight region, for example, when the forward speed of the airframe is 70 kt, the descent rate is 300 f.
The BVI noise becomes maximum at t / min. Below, the forward speed is 70 kt and the descent rate is 300 ft / m.
The case of in is called “maximum case”, and the flight direction angle in this maximum case is γ ^* .

In FIG. 7, the vertical axis represents the rotor attack angle α _TPP , and the horizontal axis represents the resistance Df acting on the airframe. In the descent flight state, the flight direction angle γ is “negative”, so “−γ” in the second term on the right-hand side has a “positive” value). As shown in FIG. 7, assuming that the resistance acting on the vehicle body before the control is Df ₀ , in the “maximum case”, the value of the rotor attack angle α _TPP is almost the same as shown at point A in FIG. It is zero, and BVI noise is generated.

Here, the control computer 90, which is the control means according to the present embodiment, rotates the flap 50, which is the resistance increasing means, to increase the resistance acting on the machine body. As a result, the resistance is Df ₁ . When it exceeds, the point A on the graph of the equation (2) in the “maximum case” moves to the point A ₁ and the value of the rotor attack angle α _TPP becomes “negative”. This means that the main rotor 20 is inclined forward. Therefore, in the "maximum case", the blade tip vortex generated from the tip of the preceding rotor blade passes under the following rotor blade, and the generation of BVI noise is suppressed.

As described above, in the slow descent flight region, if the resistance acting on the airframe is increased to exceed Df ₁ , the value of the rotor attack angle α _TPP will always be “negative” and uniform flow will occur. Therefore, the rotor blade surface is inclined forward. Therefore, the blade tip vortex generated from the tip of the preceding rotor blade always passes “below” the following rotor blade, and the generation of BVI noise is suppressed.

<Control operation relating to the descent flight area> Next,
Of the BVI noise generation area, the descent rate is about 300 to about 600 ft
The control operation related to the flight area of / min (above and below, referred to as “descent flight area”) will be described. The control operation related to the swooping flight region is such that the tip vortex generated from the tip of the preceding rotor blade passes "above" the following rotor blade (see FIG. 3 (c)).
By virtue of being positively generated, the generation of BVI noise is suppressed.

Specifically, the forward speed of the machine body detected by the speedometer 70 is in the range of about 40 to about 100 kt, and the rate of descent of the machine body detected by the lift 80 is about 3.
When it is in the range of 0 to about 600 ft / min, the control computer 90 increases the thrust acting on the airframe by the auxiliary propulsion fan 60 and decreases the resistance Df acting on the airframe.

When the resistance Df acting on the airframe decreases, the rotor attack angle α _TPP increases in the positive direction (upward) according to the equation (2), and the main rotor 20 tilts rearward. Therefore, the tip vortex generated from the tip of the preceding rotor blade passes "above" the following rotor blade. As a result, it is possible to avoid the interference between the blade tip vortex and the following rotary blade, so that it is possible to suppress the generation of BVI noise.

FIG. 8 shows the relationship between the angle of the flap 50 and the forward speed of the airframe in this descent flight region, and the relationship between the thrust (weight ratio) by the auxiliary propulsion fan 60, which is a propulsion means, and the forward speed of the airframe. Is shown. This Figure 8
As shown in Fig. 4, when the forward speed of the airframe is in the range of 0 to 40 kt, the flap 50 is set to 90 ° so as not to obstruct the flow of the downwind flow created by the main rotor 20. The efficiency can be improved. When the forward speed of the airframe exceeds 40 kt, the angle of the flap 50 is gradually returned from 90 ° to 0 ° to reduce the resistance acting on the airframe.

On the other hand, as shown in FIG. 8, when the forward speed of the airframe exceeds 40 kt, the thrust (weight ratio) by the auxiliary propulsion fan 60 is increased to reduce the resistance acting on the airframe. BVI with forward speed of about 40 to 100 kt
By increasing the thrust of the auxiliary propulsion fan 60 in the noise generation region, the resistance Df acting on the airframe can be reduced, and the main rotor 20 is tilted rearward,
Generation of BVI noise can be suppressed.

Next, the BVI noise suppression control operation relating to the descent flight region will be described with reference to FIG. 9 which is a graph of the equation (2).

Similar to FIG. 7, FIG. 9 shows a graph of the equation (2) in the above-mentioned "maximum case" in which the vertical axis represents the rotor attack angle α _TPP and the horizontal axis represents the resistance Df acting on the airframe. ing. As shown in FIG. 9, assuming that the resistance acting on the airframe before control is Df ₀ , in the “maximum case”, the value of the rotor attack angle α _TPP is almost as shown at point A in FIG. It is zero, and BVI noise is generated.

Here, the control computer 90, which is the control means according to the present embodiment, increases the thrust of the auxiliary propulsion fan 60, which is the propulsion means, to reduce the resistance acting on the airframe. Becomes smaller than Df _2, point A on the graph of the equation (2) in the “maximum case” moves to point A ₂ , and the value of the rotor attack angle α _TPP becomes “positive”. This means that the main rotor 20 is tilted rearward. Therefore, in the "maximum case", the blade tip vortex generated from the tip of the preceding rotor blade passes "above" the following rotor blade, and the generation of BVI noise is suppressed.

As described above, in the descent flight region, if the resistance acting on the airframe is reduced to be smaller than Df ₂ , the value of the rotor attack angle α _TPP will always be “positive”, and for a uniform flow. The rotor surface will be inclined rearward. Therefore, the blade tip vortex generated from the tip of the preceding rotor blade always passes "above" the following rotor blade, and the generation of BVI noise is suppressed.

Incidentally, due to the relative relationship between the forward speed of the airframe and the descent rate, a case such as the "maximum case" that belongs to both the slow descent flight area and the steep descent flight area occurs. In such a case, by adopting one of the control operation related to the “slow descent flight area” and the control operation related to the “deep descent flight area”, B
Generation of VI noise can be suppressed.

Next, the BVI noise suppression control operation using the composite rotorcraft according to the present embodiment will be described from the viewpoint of "movement of BVI noise generation area".

When BVI noise suppression control is not performed using the composite rotorcraft according to the present embodiment, the BVI noise generation area is shown by the area shown in FIG. 4 as described above. The "maximum noise area" L (a flight area with a forward flight speed of the aircraft of about 60 to about 80 kt and a descent rate of about 200 to about 400 ft / min) in the area shown in FIG. 4 is shown in FIG.
The solid line is shown at 0.

In the BVI noise suppression control operation using the composite rotorcraft according to the present embodiment, as described with reference to FIG. 7, the resistance acting on the airframe is increased in the "slow descent region" to increase the Df ₁ And the rotor attack angle α _TPP
By controlling that the value of is always "negative",
The blade tip vortex generated from the tip of the preceding rotary blade is passed "below" the subsequent rotary blade to suppress the generation of BVI noise.

That is, when the control operation relating to the "slow descent flight region" is performed using the composite rotorcraft according to the present embodiment, the control operation is performed from the "maximum noise region" L shown in FIG. BVI noise will be generated in the region L ₁ that has moved in the direction). However, in the area L ₁ that has moved downward from the “maximum noise area” L, the above-described “dive flight area” control operation is performed, so that BVI noise does not occur.

On the other hand, in the BVI noise suppression control operation using the composite rotorcraft according to the present embodiment, as explained in FIG. 9, the resistance acting on the airframe is reduced in the "descent flight region" to reduce the Df. Rotor attack angle α smaller than _{2
By controlling the TPP} value so that it is always "positive", the blade tip vortex generated from the tip of the preceding rotor blade is passed "above" the following rotor blade to suppress the generation of BVI noise. is doing.

That is, when the control operation related to the "deep descent flight range" is performed using the composite rotorcraft according to the present embodiment, the control operation is performed from the "maximum noise range" L shown in FIG. BVI noise will be generated in the area L ₂ that has moved to (1). However, in the area L ₂ that has moved upward from the “maximum noise area” L, the above-mentioned control operation of the “slow descent flight area” is performed, so that BVI noise is not generated.

The composite rotorcraft according to the present embodiment is
It has a fixed blade 40 for generating a lift force and an auxiliary propulsion fan 60 which is a propulsion means provided on the body 10 separately from the main rotor 20 for generating a forward thrust. Therefore,
Since a part of the lift of the main rotor 20 can be applied to the fixed blade 40 and the propulsion force can be obtained by the auxiliary propulsion fan 60, the speed can be increased.

Further, the composite rotorcraft according to the present embodiment is provided with a flap 50 which is a resistance increasing means for increasing the resistance acting on the airframe, and the flap 50 and the auxiliary propulsion unit depending on the forward speed and the descent rate of the airframe. And a control computer 80 which is a control means for controlling the fan 60. The control computer 80 controls the flap 50 in the slow descent flight region when the forward speed and the descent rate of the airframe are in the BVI noise generation region. To increase the resistance acting on the airframe to incline the rotor blade surface forward, and control the auxiliary propulsion fan 60 to increase the forward thrust acting on the airframe in a steep descent flight region where the descent rate of the airframe is relatively large. Since the rotor blade surface is inclined backward,
By performing different control operations in the slow descent flight area and the steep descent flight area, it is possible to effectively suppress the generation of BVI noise.

That is, in the "slow descent flight region", when the flap 50 is driven by the control computer 90 to increase the resistance Df acting on the airframe and the rotor blade surface is inclined forward, the preceding rotor blade is moved forward. The tip vortices flowing out of the blades pass "below" the following rotor blades, so that the interference between these tip vortices and the following rotor blades is avoided, and the generation of BVI noise is suppressed. You can Further, in the “descent flight region”, when the control computer 90 increases the forward thrust by the auxiliary propulsion fan 60 to reduce the resistance Df acting on the airframe and tilts the rotary blade surface backward, the preceding rotation is performed. The tip vortices flowing out from the blade vanes pass “above” the subsequent rotor blades, so that the interference between these tip vortices and the subsequent rotor blades is avoided, and the generation of BVI noise is suppressed. can do.

As a result, the maximum speed is higher than that of a normal rotary-wing aircraft, high-speed flight can be realized, and the generation of BVI noise can be suppressed to reduce the noise. That is, high speed and low noise can be achieved at the same time.

Furthermore, the composite rotary wing aircraft according to the present embodiment has a flap 50 provided on the trailing edge side of the fixed wing 40.
Can also function as a resistance increasing means,
There is no need to separately provide resistance increasing means.

[Second Embodiment] A composite rotorcraft according to the present embodiment is the same as the composite rotorcraft according to the first embodiment except that the resistance increasing means is changed. Are substantially the same, so
Descriptions of the overlapping configurations will be omitted.

In the present embodiment, as shown in FIG. 11, the fixed wing 42 is rotatable about the rotary shaft 52. That is, the fixed wing 42 has a variable attachment angle under the control of the control computer 90, and can be caused to function as a resistance increasing means by rotating 90 ° as shown in FIG. Can contribute to the suppression of the occurrence of.

[Third Embodiment] A composite rotorcraft according to the present embodiment is the same as the composite rotorcraft according to the first embodiment, except that only the resistance increasing means is changed. Are substantially the same, so
Descriptions of the overlapping configurations will be omitted.

In this embodiment, as shown in FIG. 12, the spoiler 53 is provided on the upper and lower surfaces of the fixed blade 43. The spoiler 53 is opened and closed under the control of the control computer 90, and serves as a resistance increasing means B.
It is possible to contribute to the suppression of the generation of VI noise.

[Fourth Embodiment] In the composite rotorcraft according to the present embodiment, the structure behind the tail boom and the propulsion means are changed in the composite rotorcraft according to the first embodiment. Since the other configurations are substantially the same, the description of the overlapping configurations will be omitted.

In this embodiment, as shown in FIG. 13, a tail rotor 34 is provided in place of the anti-torque control vane 30 in order to cancel the torque of the main rotor 10, and the horizontal tail 12 is attached to the tail boom 11. And a vertical tail 13 is provided. Further, a pusher propeller 64 is provided behind the tail rotor 34. The pusher propeller 64 is drive-controlled under the control of the control computer 90, and can contribute to suppressing the generation of BVI noise as a propulsion means.

[Fifth Embodiment] The composite rotorcraft according to the present embodiment is the same as the composite rotorcraft according to the first embodiment, except that the main rotor of the coaxial reversal type is adopted to counter torque. Since the control vane is not necessary and the propulsion means is changed, and the other constituents are substantially the same, the description of the overlapping construction will be omitted.

In the present embodiment, as shown in FIG. 14, a horizontal tail 12A and a vertical tail 13A are provided behind the tail boom 11, and the ducted fan 6 is used.
5 is provided. The ducted fan 65 is driven and controlled under the control of the control computer 90, and can contribute to the suppression of the generation of BVI noise as a propulsion means.

[0086]

According to the first aspect of the present invention, the maximum speed is higher than that of an ordinary rotary wing aircraft, high-speed flight can be realized, and the generation of BVI noise is suppressed to reduce the noise. be able to. That is, high speed and low noise can be achieved at the same time.

According to the second aspect of the present invention, different control operations are performed in the "slow descent flight region" and the "deep descent flight region", and the generation of BVI noise can be effectively suppressed.

That is, in the "slow descent flight region", the resistance increasing means is controlled by the control means to increase the resistance acting on the airframe to incline the rotor blade surface and flow out from the preceding rotor blade. Generation of BVI noise can be suppressed by allowing the tip vortex to pass "below" the following rotor blade to avoid interference between the tip vortex and the following rotor blade.

Further, in the "descent flight region", the control means controls the propulsion means to increase the forward thrust acting on the airframe to incline the rotary blade surface to the rear, and the blades flowing out from the preceding rotary blades. Generation of BVI noise can be suppressed by allowing the end vortex to pass "above" the trailing rotor blade to avoid interference between the tip vortex and the trailing rotor blade.

According to the third aspect of the present invention, the movable blade provided on the trailing edge side of the fixed blade can function as a flap or a spoiler and at the same time as a resistance increasing means.

According to the invention described in claim 4, since the mounting angle of the fixed blade is variable, the fixed blade itself can function as a resistance increasing means.

[Brief description of drawings]

FIG. 1 is a view for explaining a configuration of a composite rotorcraft according to a first embodiment of the present invention, (a) is a side view, and (b) is a plan view of a B portion of (a). (View from above)
Is.

FIG. 2 is a view for explaining the principle of generation of BVI noise, and is an explanatory view showing a state of a locus of a blade tip vortex and a blade tip vortex interference position as viewed from above a main rotor.

3A and 3B are diagrams for explaining the principle of generation of BVI noise. FIG. 3A is a trajectory of a blade tip vortex during horizontal flight, and FIG. 3B is a blade tip vortex when descending at a predetermined descent rate. The trajectory of
(C) is an explanatory view showing a trajectory of a wing tip vortex when descending at a descent rate larger than that in (b) as viewed from the side of the main rotor.

FIG. 4 is a distribution diagram showing a region where BVI noise is generated.

FIG. 5 is an explanatory diagram for explaining the principle of the BVI noise suppression control operation using the composite rotorcraft according to the first embodiment of the present invention.

FIG. 6 is a view for explaining a BVI noise suppression control operation in a slow descent flight region using the composite rotorcraft according to the first embodiment of the present invention, and (a) is resistance increasing means. It is a graph showing the relationship between the angle of the flap and the forward speed of the machine body, and (b) is a graph showing the relationship between the thrust force (weight ratio) of the auxiliary propulsion fan that is the propulsion means and the forward speed of the machine body.

FIG. 7 is a diagram showing a change in the rotor attack angle with an increase in resistance acting on the airframe in the BVI noise suppression control operation in the slow descent flight region using the composite rotorcraft according to the first embodiment of the present invention. It is a Df- (alpha) _TPP diagram for demonstrating.

FIG. 8 is a view for explaining a BVI noise suppression control operation in a steeply descending flight region using the composite rotorcraft according to the first embodiment of the present invention, and (a) is a flap that is a resistance increasing means. Is a graph showing the relationship between the angle of and the forward speed of the machine body, and (b) is a graph showing the relationship between the thrust (weight ratio) of the auxiliary propulsion fan that is the propulsion means and the forward speed of the machine body.

FIG. 9 shows a change in the rotor attack angle with a decrease in resistance acting on the airframe in the BVI noise suppression control operation in the descent flight region using the composite rotorcraft according to the first embodiment of the present invention. It is a Df- (alpha) _TPP diagram for demonstrating.

FIG. 10 is a distribution diagram for explaining a BVI noise suppression control operation using the composite rotorcraft according to the first embodiment of the present invention from the viewpoint of “movement of BVI noise generation region”.

FIG. 11 is a side view showing the resistance generating means (fixed wing) of the composite rotorcraft according to the second embodiment of the present invention.

FIG. 12 is a side view showing a resistance generating means (spoiler) of a composite rotorcraft according to a third embodiment of the present invention.

FIG. 13 is a perspective view showing a propulsion means (pusher-propeller) of a composite rotorcraft according to a fourth embodiment of the present invention.

FIG. 14 is a perspective view showing a propulsion means (ducted fan) of a composite rotary wing aircraft according to a fifth embodiment of the present invention.

FIG. 15 is a perspective view of a conventional composite rotorcraft.

FIG. 16 is an explanatory diagram for explaining the principle of generation of BVI noise.

FIG. 17 is a plan view of a conventional rotorcraft.

[Explanation of symbols]

10 torso 11 tail boom 12 Horizontal stabilizer 12A horizontal stabilizer 13 Vertical stabilizer 13A Vertical stabilizer 20 main rotor 21 Transmission 22 engine 30 Anti-torque control vanes 34 tail rotor 40 fixed wing 42 fixed blades (variable mounting angle) 43 fixed wing 50 flaps 52 rotation axis 53 Spoiler 60 Auxiliary propulsion fan 61 Drive Shaft for Fan 62 Fan drive transmission 64 pusher-propeller 65 Ducted Fan 70 Speedometer 80 lift 90 Control computer 100 Conventional compound rotorcraft 200 Conventional Rotorcraft 210 torso 220 resistance plate

Claims (4)

[Claims] 1. A composite rotary wing aircraft having fixed blades for generating lift force and propulsion means provided on the fuselage separately from the rotary blades for generating forward thrust, in order to increase resistance acting on the airframe. A composite rotorcraft comprising: an increasing means; and a control means for controlling the resistance increasing means and the propulsion means according to a forward speed and a descent rate of the airframe. 2. The control means controls the resistance increasing means in a slow descent flight region in which the descent rate of the airframe is relatively small, when the forward speed and the descent rate of the airframe are in the BVI noise generation region. The rotor blade surface is inclined forward by increasing the acting resistance, and the propulsion means is controlled to increase the forward thrust acting on the aircraft body in the descent flight region where the aircraft descent rate is relatively large. The compound rotorcraft according to claim 1, wherein the surface is inclined rearward. 3. The composite rotorcraft according to claim 1, wherein the fixed wing is provided with a movable wing on a trailing edge side thereof, and the resistance increasing means is the movable wing. 4. The composite rotorcraft according to claim 1, wherein the fixed wing has a variable attachment angle, and the resistance increasing means is the fixed wing.