JP2002284099A - Rotor blades of rotary wing aircraft - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In a rotorcraft, the BVI noise generated at the time of landing and the like is sufficiently reduced, and the airspeed of the rotor blades reaches a transonic range during forward flight. Improve flight characteristics in case. SOLUTION: At the tip of a main wing 11 of a rotary wing blade 10,
A leading edge 12a continuous with the leading edge 11a of the main wing 11;
Sub wing 12 having a chord length c1 shorter than chord length c
Is provided, the tip vortex generated from the tip is divided into two, and they interfere with each other and are weakened and diffused, so that the tip derived from the tip of the preceding rotor blade 10 The interference between the vortex and the following rotor blade 10 is greatly reduced, and the BVI noise is reduced. Further, since the main wing 11 and the sub wing 12 each have a swept-back shape, the airspeed in a direction perpendicular to the blade edge of the rotary wing blade 10 is reduced, and as a result, transonic speed characteristics are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor blade of a rotary wing aircraft, and more particularly, to reducing noise generated when the rotary wing aircraft lands and improving transonic characteristics during forward flight. The present invention relates to a rotor blade of a rotating rotor aircraft.

[0002]

2. Description of the Related Art Rotary wing aircraft have been used in various fields such as transportation of goods, rescue of lives, and national defense. When this rotary wing aircraft lands, for example,
As shown in the figure, the tip vortex 101 generated from the tip of the preceding rotor blade 100a and the following rotor blade 100b
Noise is generated by interference between the two. This noise is called BVI (Blade Vortex Interaction) noise.

It is known that the strength of the tip vortex, which is one of the factors of the BVI noise, is affected by the tip shape of the rotor blade. Conventionally, the blade tip shape of the rotary blade is rectangular. However, in order to reduce the BVI noise, a helicopter rotor blade disclosed in Japanese Patent Application Laid-Open No. 4-262994 has been proposed (see FIG. 14). ). This is provided with a tip blade 112 having an average chord length and a span width greater than 50% of the chord length at the center of the base blade 111 at the tip of the base blade 111.

In the above-described helicopter rotor blade, two substantially equal strength tip vortices 111a and 112a are generated by being divided by the base wing 111 and the tip wing 112, and the leading wing vortex and the succeeding rotor wing are separated. To prevent interference.

However, in the above-described helicopter rotor blade, since the two divided wing vortices 111a and 112a do not positively interfere with each other, the two wing vortices hardly diffuse and sufficiently generate BVI noise. There was a disadvantage that it could not be reduced. Further, the tip blade 112 of the helicopter rotor blade has a relatively long blade width, so that it is necessary to particularly increase the strength of the blade root portion.

As a solution to the above-mentioned drawbacks of the helicopter rotor blade, there is a rotor blade disclosed in Japanese Patent Application Laid-Open No. 4-314693 (see FIG. 15). This rotating wing has a saw-shaped tooth 1 at the tip of the blade 121.
22, the tip vortex 123 is discharged along the teeth, and the tip vortex 123 is divided by the number of the teeth 122 and weakened.

[0007]

By the way, when the rotary wing aircraft flies forward, the flight speed is added to the rotation speed of the forward rotor blades. For this reason, a situation may occur in which the airspeed of the rotor blade enters the transonic range, that is, the airspeed exceeds the speed of sound on a part of the surface of the rotor blade. In such a case, a shock wave is generated on a part of the surface of the rotor blade and the resistance rapidly increases,
May adversely affect flight conditions. Accordingly, in a rotary wing aircraft, the aforementioned BVI noise is reduced,
In addition to the problem described above, it is necessary to solve the problem of improving flight characteristics under transonic conditions.

The blade 121 having the above-mentioned saw-shaped teeth 122 can reduce the tip vortex by the teeth 122, but it is not sufficient from the viewpoint of the above-mentioned flight characteristics in the transonic state. . That is, since the plane shape of the wing tip of the blade 121 has a rectangular shape as a whole, a shock wave is still generated under the above-described transonic state, and the improvement of the flight characteristics has not been improved.

An object of the present invention is to provide a rotary wing aircraft
It is an object of the present invention to sufficiently reduce BVI noise generated at the time of landing and the like, and to improve flight characteristics when the airspeed of the rotor blade reaches a transonic range during forward flight.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 is, for example, shown in FIG. 1, in which a rotary blade having a base end attached to a rotor head of a rotary drive unit. In the rotor blade 10 of the aircraft, the rotor blade 10 includes a main wing 11 whose base end is attached to a rotor head of a rotation drive unit, and a sub wing 12 provided at a tip end of the main wing 11. The main wing 11 and the sub wing 1
2 is a trailing edge 11b rather than a leading edge 11a (12a).
(12b) is extended to the outside of the wing tip.
Is characterized by having a leading edge 12a continuous with the leading edge 11a of the main wing 11, and a chord length c1 shorter than the chord length c of the main wing 11.

According to the first aspect of the present invention, by providing the sub wing 12 having a specific shape at the tip of the main wing 11, the sub wing 1
2 and a weak tip vortex generated from the wing tip of the main wing 11. Since these two tip vortices are close to each other, they positively interfere with each other and are weakened and diffused.

As a result, when a rotary wing aircraft lands, the tip vortex generated from the tip of the preceding rotor blade 10 is aggressively interfered with the following rotor blade 10 before it interferes with the following rotor blade 10. Can be weakened. Therefore, the BVI noise is significantly reduced.

According to the first aspect of the present invention, the rear edge 11b (12b) of each of the main wing 11 and the sub wing 12 is extended outward of the wing tip from the front edge 11a (12a). The leading edge of the leading edge 11a (12a) and the trailing edge 11b (12
The tip of b) is connected by a straight or curved wing tip edge to provide a sweepback angle. Therefore, FIG.
As shown in (1), the airspeed in the direction perpendicular to the blade edges of the main wing 11 and the sub wing 12 can be reduced, and the generation of a shock wave can be delayed as compared with the conventional rotary blade.
That is, the conventional rotor blades can maintain normal flight characteristics even when the speed reaches such a level that the resistance increases due to the generation of a shock wave.

According to a second aspect of the present invention, in the rotary wing blade of the rotary wing aircraft according to the first aspect, for example, as shown in FIGS. 1 and 9, the sub wing 12 has a wing width of the main wing. 11 is characterized in that it extends outwardly from the wing width of the main wing 11 by a length b1 of 0 to 50% of the chord length c of the wing 11.

According to the second aspect of the present invention, the wing width of the sub wing 12 is made to protrude outward by a specific length b1 from the wing width of the main wing 11 to the outside of the wing tip. And the tip vortex generated from the wing tip of the main wing 11 can be generated while being separated by a specific distance. As a result, these two tip vortices can more positively interfere with each other and be weakened.

According to a third aspect of the present invention, in the rotary wing blade of the rotary wing aircraft according to the first aspect, for example, as shown in FIG.
It is characterized by having a dihedral angle δ1, δ2 of 30 °.

According to the third aspect of the present invention, since the main wing 11 and the sub wing 12 have the dihedral angles δ1 and δ2, the tip vortex generated from the tip of the rotary blade 10 is discharged downward. Is done. For this reason, the preceding rotor blade 10
The tip vortex generated from the wing tip of the rotating blade 10
As a result, the BVI noise is more effectively reduced.

According to the third aspect of the present invention, the tip vortex generated from the tip of the rotor blade 10 is discharged downward, so that the subsequent rotor blade due to the flow induced by the tip vortex. The partial stall at the time can be suppressed. As a result, energy loss at the time of driving the rotor can be reduced, and hovering performance at the time of stopping the rotor aircraft in the air can be improved.

According to a fourth aspect of the present invention, in the rotary wing blade of the rotary wing aircraft according to the first aspect, for example, as shown in FIGS. 1 and 9, the sub wing 12 has a chord length of the main wing 11. It has a chord length c1 of 10 to 30% of c.

According to the fourth aspect of the invention, by setting the chord length c1 of the sub-wing 12 to a specific length, the strength of the tip vortex can be adjusted. The tip vortex generated from the wing tip and the wing tip vortex generated from the wing tip of the main wing 11 can be more effectively interfered with each other and weakened.

According to a fifth aspect of the present invention, in the rotary wing blade of the rotary wing aircraft according to the first aspect, for example, as shown in FIG.
It has a mounting angle θ of up to 5 °.

According to the fifth aspect of the present invention, the strength of the wing tip vortex can be adjusted by setting the attachment angle θ of the sub wing 12 to the main wing 11 to a specific value.
The tip vortex generated from the wing tip of the sub wing 12 and the wing vortex generated from the wing tip of the sub wing 12 can be more effectively interfered with each other and weakened.

According to a sixth aspect of the present invention, in the rotary wing blade of the rotary wing aircraft according to the first aspect, for example, as shown in FIGS. 10 and 11, the sub wing 12 is retracted with respect to the main wing 11. It is characterized by having.

According to the invention of claim 6, the sub wing 12
Is retracted with respect to the main wing 11, so that the sub wing 12
The tip vortex generated from the wing tip of the main wing 11 and the wing tip vortex generated from the wing tip of the main wing 11 can more effectively interfere with each other and be weakened. Further, since the airspeed of the sub wing 12 with respect to the blade edge is further reduced, the transonic characteristics can be further improved.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a rotor blade of a rotor aircraft according to the present invention will be described below in detail with reference to the drawings.

[First Embodiment] A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view showing a portion near a wing tip of a rotor blade 10 of a rotor aircraft according to the present embodiment. Rotor blade 10 shown in FIG.
Are attached to a rotor hub (not shown) to form a rotor.

The rotary wing blade 10 includes a main wing 11 and a sub wing 12. The main wing 11 and the sub wing 12 have trailing edges 11b and 12b respectively extended from the leading edges 11a and 12a toward the wing tip side. .

In this embodiment, as shown in FIG. 1, the main wing 11 has a substantially uniform chord length c up to the tip of its leading edge 11a. The tip of the edge 11a and the tip of the trailing edge 11b are connected by a smooth parabolic wing tip. The sub wing 12 also has a wing tip shape similar to that of the main wing 11.

The leading edge 12a of the sub wing 12 is continuous with the leading edge 11a of the main wing 11, and the chord length c1 of the sub wing 12 is
It is shorter than the chord length c of the main wing 11, and has a length of 10 to 30% of the chord length c of the main wing 11. In addition, sub wing 1
The rear edge 12b of the main wing 11 is extended further to the wing tip than the rear edge 11b of the main wing 11, and the extended length b1 is set to a length of 0 to 50% of the chord length c of the main wing 11. .

The chord length c1 of the sub wing 12 can be appropriately determined within the above-described range according to the size and the rotation speed of the rotor blade 10 and the flight speed of the rotor aircraft.

Similarly, the length b1 of extending the wing width of the sub wing 12 to the outside of the wing tip from the wing width of the main wing 11 is the same as that of the rotating wing 10
Can be appropriately determined according to the size, rotation speed, and flight speed of the rotary wing aircraft.

The rotor blade 1 according to the embodiment described above.
0 and a conventional rotor blade 100 having a rectangular shaped blade tip.
In FIG. 2, the situation of the tip vortex diffusion is shown in FIG. 2 and compared. In the conventional rotary blade 100 having a rectangular tip shown in FIG. 2A, one strong tip vortex 100a is generated from the tip, and the tip vortex 100a flows backward without being diffused. .

On the other hand, according to the rotary blade 10 of the present embodiment shown in FIG. 2B, the tip vortex generated from the wing tip The wings are divided into two relatively weak vortices: a main wing vortex 11c) and a tip vortex generated from the wing tip of the sub wing 12 (hereinafter, referred to as a "sub wing vortex 12c"). Here, since the wing width of the sub wing 12 is longer than the wing width of the main wing 11, the sub wing vortex 12 c flows backward while passing near the outside of the wing tip of the main wing 11, Main wing vortex 11c
Will actively interfere with each other.

That is, as shown in FIG. 2 (c), the right side portion of the main wing vortex 11c rotating in the counterclockwise direction shows the main wing vortex 11c and the sub wing vortex 12c viewed from the rear. The vortex 12c is offset with the left portion, and the vortex 12 is diffused as a whole in a weakened state.

As a result, the strength of the tip vortex generated from the preceding rotor blade 10 is greatly reduced, and this tip vortex and
BV generated by interference with the following rotor blade 10
I noise will be greatly reduced.

Next, referring to FIGS. 3 and 4, the conventional rotor blade 100 and the rotor blade 1 according to the present embodiment will be described.
The generation situation of the tip vortex with zero is compared with the wind tunnel experiment result.

FIGS. 3 and 4 show a conventional rotor blade 10.
0 and the rotor blade 10 according to the present embodiment,
The vorticity contour h and the wake velocity vector v are measured at three chords behind the trailing edge of each rotor blade. The condition at this time is that the wind speed is 40 m / s, the angle of attack is 10 °, the density of the vorticity contour h is low, and the shorter the wake velocity vector v, the better the vortex diffusion. Thus, the BVI noise can be reduced.

Comparing the results of the wind tunnel experiments shown in FIGS.
It is clear that the tip vortex of the conventional rotary blade 100 is a strong vortex from the density of the vorticity contour h and the length of the wake velocity vector v shown in FIG.

On the other hand, the tip vortex of the rotor blade 10 according to the present embodiment is divided into a main wing vortex 11c and a sub wing vortex 12c, as shown in FIG. And the length of the wake velocity vector v is also reduced by 30% as compared with the wake velocity vector shown in FIG. 3, so that the main wing vortex 11c and the sub wing vortex 12c positively interact with each other. It is clear that the interference has effectively weakened.

Next, referring to FIGS. 5 and 6, the transonic characteristics of the rotor blade 10 according to the present embodiment will be demonstrated.

FIG. 5 shows a rotor blade 1 according to the present embodiment.
FIG. 2 shows a portion near the wing tip of the sub wing 12 (main wing 11) of FIG. Assuming that the uniform flow velocity with respect to the rotor blade 10 is V∞, as is apparent from FIG.
The airspeed of the 2 (main wing 11) in the direction perpendicular to the wing tip is set to V {cos} due to the effect of the sweepback angle Λ.

In particular, the rotor blade 10 according to the present embodiment
Sub wing 12 (main wing 11) has a leading edge 12a (11a)
And the tip of the trailing edge 12b (11b) are connected by a parabolic wing tip in which the sweepback angle 増 大 gradually increases toward the trailing edge, so that the wing tip of the sub wing 12 (main wing 11) is connected. The airspeed in the direction perpendicular to the airplane becomes smaller toward the trailing edge.

Therefore, even when the uniform flow velocity V∞ approaches the sound velocity, the airspeed in the direction perpendicular to the blade edge of the sub wing 12 (main wing 11) of the rotor blade 10 is the uniform flow velocity. Since it is smaller than V∞, it is difficult to reach the speed of sound, and it is difficult to generate a shock wave. As a result, a rapid increase in resistance can be avoided.

FIG. 6 shows a rotor blade 1 according to this embodiment.
9 shows the results of a wind tunnel test demonstrating a transonic characteristic of 0.
In FIG. 6, C _D is the drag coefficient on the vertical axis, M of the horizontal axis is the Mach number, the dotted line, the C _D -M curve at the rotor blade 100 having a blade tip of a conventional rectangular shape, and the solid line ,
Shows the C _D -M curve in rotor blade 10 of the present embodiment.

The two C _D -M curve above a tangent is drawn (slope 0.1) was compared to seek the value of M _DD (Mach number whose resistance rapidly). As is apparent from FIG. 6, the rotor blade 10 according to the present embodiment has a value of M _DD about 0.01 compared to the conventional rotor blade 100 having a rectangular tip.
5 large, which proved to be excellent in transonic characteristics.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIG. In addition, FIG.
FIGS. 3A and 3B are a plan view (a) and a side view (b) of a portion near a blade tip of a rotor blade 10 corresponding to FIG. 1 according to the first embodiment. By attaching, the detailed description of that portion is omitted, and different portions will be mainly described.

In the rotor blade 10 according to the present embodiment, as shown in FIG. 7B, both the main wing 11 and the sub wing 12 have a dihedral angle. The dihedral angle δ1 of the main wing 11 and the dihedral angle δ2 of the sub wing 12 can both be set in the range of 0 ° to 30 °.

The dihedral angle δ1 of the main wing 11 and the dihedral angle δ2 of the sub wing 12 are within the above-mentioned ranges, depending on the size and rotation speed of the rotor blades and the flight speed of the rotor aircraft. It can be determined as appropriate.

According to the rotor blade 10 of the present embodiment thus formed, in addition to the first embodiment, the main wing 11 and the sub wing 12 have the dihedral angles δ1 and δ2, respectively. The tip vortex is discharged downward.
For this reason, the tip vortex generated from the tip of the preceding rotor blade 10 hardly interferes with the following rotor blade 10,
As a result, the BVI noise is reduced even more effectively.

According to the rotor blade 10 of the present embodiment, the tip vortex generated from the blade tip of the rotor blade 10 is discharged downward, so that the subsequent rotation by the flow induced by the blade vortex is performed. Partial stall in the blade can be suppressed. As a result, energy loss at the time of driving the rotor can be reduced, and hovering performance at the time of stopping the rotor aircraft in the air can be improved.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIG. In addition, FIG.
FIGS. 2A and 2B are a plan view (a) and a side view (b) of a vicinity of a blade tip of the rotary blade 10 corresponding to FIG. 1 in the first embodiment, and corresponding parts have the same reference numerals. , A detailed description of the portion will be omitted, and different portions will be mainly described.

The sub wing 12 of the rotary blade 10 according to the present embodiment has an attachment angle θ as shown in FIG. 8B. Can be set in the range of -5 ° to 5 °. The mounting angle θ can be appropriately determined in accordance with the size and rotation speed of the rotary wing blade 10 and the flight speed of the rotary wing aircraft within the above-described range.

According to the rotor blade 10 of the present embodiment formed in this way, in addition to the first embodiment, the sub-wing 12 sets the mounting angle θ to an optimum value, thereby achieving a tip vortex. Since the intensity of the vortex can be adjusted, the vortex can be more effectively diffused. As a result, the tip vortex generated from the tip of the preceding rotor blade 10 is less likely to interfere with the following rotor blade 10, and the BVI noise is further effectively reduced.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described with reference to FIG. In addition, FIG.
FIG. 2 is a plan view showing the vicinity of the blade tip of the rotor blade 10 corresponding to FIG. 1 in the first embodiment, and a detailed description of that portion is omitted by assigning the same reference numerals to corresponding portions, The different parts will be mainly described.

In this embodiment, as shown in FIG. 9, the wing tip shape of the main wing 11 (sub wing 12) is the leading edge 11a (12a).
And the tip of the trailing edge 11b (12b) are connected by a straight blade edge.

According to the present embodiment thus formed, since the main wing 11 and the sub wing 12 have the above-mentioned wing end edges, the rotary wing in the first embodiment shown in FIGS. As in the case of the blade 10, the BVI noise reduction effect due to the diffusion of the blade tip vortex is exhibited, and even when the uniform flow velocity V∞ approaches the sound speed, the sub wing 12 (the main wing 1) of the rotary blade 10
The airspeed in the direction perpendicular to the blade edge in 1) is a uniform flow velocity V
Because it is smaller than ∞, it is difficult to reach the speed of sound, and it is difficult for shock waves to be generated. As a result, a rapid increase in resistance can be avoided.

[Fifth Embodiment] Next, a fifth embodiment of the present invention will be described with reference to FIG. Note that FIG.
FIG. 3 is a plan view showing the vicinity of the blade tip of the rotor blade 10 corresponding to FIG. 1 in the first embodiment, and the corresponding portions are denoted by the same reference numerals, and detailed description of those portions is omitted. The different parts will be mainly described.

In this embodiment, as shown in FIG. 10, in the vicinity of the blade tip of the rotary blade 10, first, the leading edge 11
a is retracted at a constant retreat angle, and the trailing edge 11b is also retracted at a constant retreat angle so as to be parallel to the leading edge 11a.
1a and the tip of the trailing edge 11b are connected by a smooth parabolic wing tip. In addition, the sub wing 12
The main wing 11 has a leading edge 12a that is continuous with the recessed portion of the leading edge 11a.

According to the present embodiment thus formed, the leading edge and the trailing edge of the main wing 11 in the vicinity of the wing tip are retreated at a constant retreat angle, and the wing 11 shown in FIGS. Since it has a parabolic blade edge similar to the rotor blade 10 in the first embodiment, it exhibits transonic speed characteristics superior to those of the rotor blade 10 in the first embodiment.

According to the present embodiment thus formed, the chord at the root of the sub wing 12 is
The wing is inclined backward with respect to the chord at the root of the wing, so that the airspeed in the direction perpendicular to the wing tip of the sub wing can be further reduced, and the transonic characteristics are further improved. be able to.

[Sixth Embodiment] Next, a sixth embodiment of the present invention will be described with reference to FIG. Note that FIG.
FIG. 13 is a plan view showing the vicinity of the blade tip of the rotor blade 10 corresponding to FIG. 10 in the fifth embodiment, and a detailed description of the corresponding portion is omitted by attaching the same reference numeral to the corresponding portion. The different parts will be mainly described.

In this embodiment, as shown in FIG. 11, the sub wing 12 has a leading edge 12a which is continuous with the retreated portion of the leading edge 11a of the main wing 11, and the wing tip shape of the sub wing 12 Is
The leading edge of the leading edge 12a and the leading edge of the trailing edge 12b are shaped to be connected by a straight blade edge. That is, in the present embodiment, the sub wing 12 in the fourth embodiment is attached to the main wing 11 in the fifth embodiment.

According to the present embodiment thus formed, the leading edge and the trailing edge of the main wing 11 in the vicinity of the wing tip are retreated at a constant retreat angle, and the wing 11 shown in FIGS. Since it has a parabolic blade edge similar to that of the rotor blade 10 of the first embodiment, the rotor blade 10 of the first embodiment has a similar shape to the rotor blade 10 of the fifth embodiment. Demonstrates excellent transonic characteristics.

The present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention. For example, in the first to sixth embodiments, the wing tip shapes of the main wing 11 and the sub wing 12 viewed from the leading edge side (the trailing edge side) have upper and lower surfaces as shown in FIG. Can be not only a rectangular shape connected by a straight line, but also a shape (shape shape) in which the upper surface and the lower surface are connected by a curved line such as an arc or a parabola as shown in FIG. .

[0065]

According to the rotary wing blade of the rotary wing aircraft of the present invention described above, the base end is provided at the tip of the main wing of the rotary wing attached to the rotor head of the rotary drive unit, and at the leading edge of the main wing. Since the continuous wing and the sub wing having a chord length shorter than the main wing chord length are provided, the wing tip vortices generated from the wing tip of the main wing and the wing tip of the sub wing positively interact with each other. They interfere and are weakened and spread. As a result, it is possible to effectively reduce the BVI noise generated due to interference between the tip vortex generated from the tip of the preceding rotor blade and the subsequent rotor blade.

According to the rotor blade of the rotary wing aircraft of the present invention, the main wing and the sub wing each have a trailing edge extending beyond the leading edge to the outside of the wing tip. Are connected at a straight or curved wing edge to provide a sweepback angle, so that the airspeed in a direction perpendicular to the wing edge can be reduced. For this reason, even when the airspeed of the rotor blade reaches the transonic range, for example, during forward flight of the rotor blade aircraft, the generation of a shock wave can be delayed as compared with the conventional rotor blade. That is, transonic characteristics can be improved.

Further, by extending the wing width of the sub wing to the outside of the wing tip by an appropriate length from the wing width of the main wing, the wing tip vortex generated from the wing tip of the main wing and the wing tip of the sub wing The generated wing tip vortex can more effectively interfere with each other, and as a result, the above-mentioned BVI noise can be further effectively reduced.

Further, by providing the main wing and the sub wing with a dihedral angle, the tip vortex generated from the tip of the rotor blade is discharged downward, so that the preceding rotor The tip vortex generated from the tip of the blade is less likely to interfere with the following rotor blade, and as a result, BVI noise is more effectively reduced. In addition, since the tip vortex generated from the tip of the rotor blade is discharged downward, it is possible to suppress a partial stall at the subsequent rotor blade due to the flow induced by the tip vortex. As a result, energy loss at the time of driving the rotor can be reduced, and hovering performance at the time of stopping the rotor aircraft in the air can be improved.

By setting the chord length of the sub wing to an appropriate value, the strength of the wing tip vortex can be adjusted, so that the wing tip vortex generated from the wing tip of the main wing can be more effectively reduced. ,
It can interfere with the tip vortex generated from the tip of the sub wing. As a result, the above-described BVI noise can be further effectively reduced.

By setting the angle of attachment of the sub wing to the main wing at an appropriate value, the strength of the tip vortex can be adjusted, so that the tip vortex generated from the wing tip of the main wing can be more effectively used. And a tip vortex generated from the tip of the sub wing. As a result, the above-described BVI noise can be further effectively reduced.

By retracting the sub wing with respect to the main wing, the airspeed in the direction perpendicular to the blade edge of the sub wing can be further reduced. As a result, the transonic characteristics can be further improved.

[Brief description of the drawings]

FIG. 1 shows a first rotor blade of a rotary wing aircraft according to the invention.
FIG. 3 is a plan view illustrating a blade tip of a rotary blade, which describes an embodiment.

FIGS. 2A and 2B are explanatory diagrams of wing tip vortex diffusion, wherein FIG. 2A is an explanatory diagram of a wing tip vortex of a conventional rotary wing blade, and FIG. 2B is an explanatory diagram of a wing tip vortex of a rotary blade according to the present embodiment. (C) is an explanatory view showing the state of the wing tip vortex of (b) viewed from the rear.

FIG. 3 is a wind tunnel experiment result showing a state of generation of a tip vortex of a conventional rotary blade.

FIG. 4 is a wind tunnel experiment result showing a state of generation of a tip vortex of a rotor blade according to the present embodiment.

FIG. 5 is an explanatory diagram showing a swept-back effect in the rotor blade according to the present embodiment.

FIG. 6 is a wind tunnel experiment result showing a transonic effect in the rotor blade according to the present embodiment.

FIG. 7 shows a second rotor blade of a rotary wing aircraft according to the invention;
It is explanatory drawing which shows the wing tip of the rotary wing blade explaining embodiment, (a) is a top view and (b) is the figure seen from the trailing edge side.

FIG. 8 shows a third rotor blade of a rotary wing aircraft according to the invention;
It is explanatory drawing which shows the wing tip of the rotary wing blade explaining embodiment, (a) is a top view and (b) is the figure seen from the wing tip side.

FIG. 9 shows a fourth rotor blade of a rotary wing aircraft according to the invention;
FIG. 3 is a plan view illustrating a blade tip of a rotary blade, which describes an embodiment.

FIG. 10 is a plan view showing a wing tip of a rotor blade of a rotor blade of a rotor blade aircraft according to a fifth embodiment of the present invention.

FIG. 11 is a plan view showing a blade tip of a rotor blade for explaining a rotor blade of a rotor blade aircraft according to a sixth embodiment of the present invention.

FIGS. 12A and 12B are diagrams showing the wing tips of the rotor blades of the rotor blade of the rotor aircraft according to the present invention viewed from the leading edge side (the trailing edge side), where FIG. 12A is a rectangular shape, and FIG. is there.

FIG. 13 is an explanatory diagram showing an outline of a rotor blade of a conventional rotor aircraft.

FIG. 14 is an explanatory view showing an outline of a conventional rotor blade.

FIG. 15 is an explanatory view showing an outline of a conventional rotor blade.

[Explanation of symbols]

Reference Signs List 10 Rotor blade 11 Main wing 11a Leading edge of main wing 11b Trailing edge of main wing 11c Main wing vortex 12 Secondary wing 12a Leading edge of secondary wing 12b Trailing edge of secondary wing 12c Secondary wing vortex c Chord length of primary wing c1 Chord of secondary wing Length b1 Length where the wing width of the sub wing is extended beyond the wing width of the main wing to the outer side of the wing tip h Vorticity contour line v Wake velocity vector C _D resistance coefficient M Mach number M Mach number at which _DD resistance increases rapidly V∞ 1 Uniform flow velocity δ1 Deflection angle of main wing δ2 Deflection angle of sub wing 後 Sweep angle θ Mounting angle

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masahiro Okukata 1-7-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Inside Fuji Heavy Industries Ltd.

Claims (6)

[Claims] 1. A rotary wing blade of a rotary wing aircraft having a base end attached to a rotor head of a rotary drive unit, wherein the rotary wing blade includes a main wing having a base end attached to a rotor head of the rotary drive unit. A main wing and a sub wing provided at a tip end of the main wing, wherein the main wing and the sub wing each have a trailing edge extending outside the wing tip from a leading edge, and the sub wing is provided at a leading edge of the main wing. A rotor blade for a rotary wing aircraft having a continuous leading edge and a chord length shorter than a chord length of the main wing. 2. The sub wing is characterized in that its wingspan extends from the chord length of the main wing by 0 to 50% of the wingspan of the main wing to the outside of the wing tip. A rotor blade for a rotor aircraft according to claim 1. 3. The rotary wing blade of a rotary wing aircraft according to claim 1, wherein the main wing and the sub wing each have a dihedral angle of 0 to 30 °. 4. The rotary wing blade of a rotary wing aircraft according to claim 1, wherein the sub wing has a chord length of 10 to 30% of a chord length of the main wing. 5. The rotary wing blade of a rotary wing aircraft according to claim 1, wherein the sub wing has an attachment angle of −5 ° to 5 ° with respect to the main wing. 6. The rotary wing blade of a rotary wing aircraft according to claim 1, wherein the sub wing is retracted with respect to the main wing.