JPH08239095A - Wing end vortex reducing device - Google Patents

Abstract

PURPOSE: To provide a wing end vortex reducing device for reducing the intensity of a wing end vortex generated from the end of a three-dimensional lift force face. CONSTITUTION: A wedge 3, where the rear end 5 is arranged rearward of the rear edge of a rotor wing 1 and the inner flank 4 is made into an incline whose rear is turned outward to the progress direction of a wing 1, is hung down from the bottom of the wing end part 2 of the wing 1, with its top fixed firmly to the bottom. Hereby, wing end vortex 7, which is generated at the end of the wing and flows rearward, becoming spiral vortex, hits against the inner flank 4 of the wedge 3, and the intensity is attenuated, and also in case that the wing 1 is a rotor wing, this gives the wing 1 torque, and rotor efficiency improves. Moreover, by the attenuation of the wing end vortex 7, the aerodynamic property of the rotor wing 1 improves, and also the drop of noise caused by the interference of wing end vortex with the rotor wing 1 and the improvement of hovering property can be accomplished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a helicopter rotor blade,
Also, the present invention relates to a wing tip vortex reducing device that is applied to a main wing of a fixed wing aircraft and reduces a wing tip vortex generated from a wing tip of these blades.

[0002]

2. Description of the Related Art When a wing having a finite length, such as a rotor of a helicopter or a main wing of a fixed wing machine, generates a lift force, a tip vortex is generated from the tip of the wing.

This wing tip vortex causes a reduction in the lift generated on the wing,
And causes an increase in the resistance that acts on the wings. In particular, when the blade is a helicopter rotary blade, deterioration of hovering performance and generation of noise due to interference between the blade tip vortex and the rotary blade become particularly serious problems. Therefore, reducing this blade tip vortex leads to improvement in blade performance, and particularly in the case of a helicopter rotor blade, it greatly contributes to improvement in helicopter performance.

The reduction device conventionally used for reducing the blade tip vortices, particularly for reducing the blade tip vortices of the helicopter rotor blades, will be described below. FIG. 5 is a diagram showing a rectangular blade in which reduction of the tip vortex is not considered at all. When such a rectangular blade 01 rotates around the rotor rotation axis and the angle of attack is given to the rectangular blade 01 by a pitch operation to generate a lift, the rectangular blade 01 generates a strong blade tip vortex 02 near the blade tip and the resistance is Therefore, the rotation torque of the rotor rotation shaft is increased.

Further, since the blade tip vortex 02 is wound inside the rectangular blade 01, the downward velocity is added to the flow of air flowing near the blade tip, so that the rectangular blade 01 near the blade tip is added.
The angle of attack of the aircraft will decrease, resulting in lower lift. Furthermore, the tip vortex 02 generated in the preceding rotating rectangular blade 01
However, since it interferes with the subsequent rectangular wing 01, it causes a local change in the angle of attack on the subsequent rectangular wing 01, which deteriorates the aerodynamic performance, deteriorates the hovering performance, and causes a large noise. Will be generated.

As described above, the taper blade 03 shown in FIG. 6 is an example conceived for reducing the blade tip vortex 02 which causes various problems. In this tapered blade 03, the strength of the blade tip vortex 02 is weakened by reducing the planar area as it goes to the blade tip.

However, in such a tapered blade 03, the strength of the blade tip vortex 02 is weakened. Therefore, if the area of the blade tip is reduced by tapering, the total lift of the tapered blade 03 is reduced, so that the weight of the airframe is reduced. In order to maintain the magnitude of the total lift for holding the taper blades, it is necessary to increase the pitch angle of the tapered blades 03, which results in an increase in resistance, and there is a problem that a sufficient effect cannot be obtained.

Further, in order to reduce the blade tip vortex 02, FIG.
In some cases, the blade end portion of the rotary blade 01 is made into the dihedral blade 04 as shown in FIG. That is, by forming the dihedral blade 04 in which the tip portion of the rotary blade 01 is lowered, the blade tip vortex 02 of the rotary blade 01 that rotates in advance can be separated from the subsequent rotary blade 01, This is intended to reduce the problems associated with the generation of the end vortex 02.

However, in the case of the rotary blade 01 provided with the dihedral blade 04, the interference between the tip vortex 02 and the rotary blade 01 including the dihedral blade 04 may increase depending on flight conditions. There is a problem that noise may increase.
Further, during forward flight, the dihedral blades 04 become a resistance, which causes a problem that the propulsive force is increased during forward flight.

Further, in order to reduce the blade tip vortex 02, there is a rotor blade 01 having a winglet blade as shown in FIG. That is, the winglet-equipped blade is configured such that the small blade 05 is provided at the blade end of the rotary blade 01, and the generated blade tip vortex 02 and the small blade 05 at the blade tip are damped.

However, although this winglet-equipped blade can reduce the strength of the tip vortex 02, it has been found that the same problem as in the rotary blade 01 provided with the dihedral blade 04 shown in FIG. 8 occurs. .

[0012]

SUMMARY OF THE INVENTION As described above, the present invention solves the problems of the conventional blade tip vortex reducing devices that have been variously performed to reduce the blade tip vortices, and eliminates the blade tip vortices. Effectively dampenes and suppresses blade efficiency reduction due to blade tip vortex interference with the blade.In addition, when the blade rotates, such as a rotary blade, its rotating torque can be reduced, and the resistance body during forward flight can be reduced. In addition, interference between the tip vortex generated in the leading rotor blade and the trailing rotor blade is reduced, the aerodynamic performance of the rotor blade is not deteriorated, hovering performance is improved, and noise is reduced. An object is to provide a blade tip vortex reduction device that can reduce the number of blade tips.

[0013]

Therefore, the blade tip vortex reducing device of the present invention has the following means. Provided with an inclined inner side surface that expands the rear side outward with respect to the traveling direction of the wing,
The upper edge of the wedge, which was arranged so that its rear end was located rearward of the rear edge of the blade, was fixed to the lower surface of the blade end portion of the blade and hung vertically.

[0014]

The blade tip vortex reducing device of the present invention performs the following actions by the above-mentioned means. The tip vortex generated from the blade tip is formed when the air on the lower surface side tries to flow into the upper surface due to the pressure difference between the upper surface and the lower surface of the blade, but because it is flown to the rear of the blade at the airspeed of the blade. , Becomes a spiral vortex. In the present invention, the wedge is arranged near the core of this spiral vortex,
By arranging the trailing edge of the wedge rearward of the trailing edge of the blade, the swirling flow of the spiral vortex efficiently hits the inner surface inclined to the outside and the spiral vortex can be significantly damped.

As a result, it is possible to suppress a decrease in lift due to the interference between the blade tip vortex and the blade and an increase in the resistance acting on the blade.

When the blade is a rotating blade that rotates around the rotor rotation axis, a rotational force is generated in the rotating blade as a reaction of the swirling flow of the spiral vortex that collides with the inner surface of the wedge and is damped. As a result, it is possible to reduce the rotational torque required to rotate the rotary blade. In addition, since the inner surface is mounted so as to be inclined, the resistance does not increase during forward flight unlike the dihedral blade or the winglet-equipped blade. Further, the local change in the attack angle of the rotor blade due to the interference between the tip vortex and the rotor blade is reduced, noise can be reduced, and the aerodynamic performance can be improved to significantly improve the hovering performance. .

[0017]

EXAMPLES Examples of the tip vortex reduction device of the present invention will be described below.
It will be described with reference to the drawings. FIG. 1 is a plan view of a helicopter rotary blade including an embodiment of the blade tip vortex reduction device of the present invention, showing one side with respect to the center of rotation of the rotary blade. Figure 2
Is an enlarged view of the wing tip of the helicopter rotor blade shown in FIG.
2A is a perspective view, FIG. 2B is a plan view, and FIG.
(C) is a front view.

As shown in the drawing, a wedge 3 is fixed to the lower surface of the blade end portion 2 of a rotary blade 1 as a blade. The wedge 3 is formed in a so-called wedge-shaped plane shape, and its upper end is fixed to the lower surface of the blade tip 2 and is provided so as to hang from the lower surface of the blade tip 2. Further, the rear end 5 of the wedge 3 is arranged at a position d from the rear edge of the rotary blade 1. The amount of protrusion d is generated at the blade tip portion 2 of the rotary blade 1 and becomes a spiral vortex, which is effective for stopping the rotational flow of the blade tip vortex 7 flowing backward, for example, a length. The length of the cord (chord) of the rotary blade 1 is about 0.5 to 1.5 times.

Further, the wedge 3 is formed such that the inner side surface 4 thereof forms an outwardly open inclined surface in which the rear side moves outward with respect to the rotating blade traveling direction V. Further, the outer side surface 6 is a problem in forward flight of the dihedral blade 04 or the winglet blade 05 described above, which is a problem in forward flight.
In order to reduce the resistance that increases in 5, the shape is rounded. The height h of the wedge 3 is
Similar to the amount of protrusion d from the trailing edge to the rear, the height is effective to stop the rotating flow of the blade tip vortex 7, for example, about 0.03 to 0.08 times the cord length of the rotor blade 1. ing.

Of course, both d and h are more effective in stopping the rotational flow of the blade tip vortex 7, but if they are too large, the aerodynamic performance is deteriorated due to an increase in resistance, or the operation of the rotor 1 is impaired. Since a new problem arises, it is preferable that the size is about the above.

Since the blade tip vortex reducing apparatus of the present embodiment has the above-described structure, as shown in FIG. 3A, the blade tip which rises from below the blade tip 2 and flows backward while descending. Vortex 7
The rotating flow is stopped at the inner surface 4 of the wedge 1, the strength of the vortex is attenuated, and a vortex diffusion flow 8 is formed, which moves backward. On the other hand, in the case of the rectangular blade 01 shown in FIG. 6 in which the wedge 3 is not provided, the blade tip vortex 02 is rearward with the strength of the vortex maintained as shown in FIG. 3 (B). Move to.

Further, a force 9 due to the blade tip vortex 3 hitting the inner surface 4 of the wedge 3 is generated on the wedge 3, and this generates a force 10 in the direction of rotating the rotor blade 2. The rotation torque is reduced, and the rotor efficiency is improved.

FIG. 4 shows the direction of the wind 11 flowing into the rotor 1 during forward flight. 4 (B) and FIG.
As shown in (C), the rotor blade 01 including the winglet blades 05 and the dihedral blades 04 stops the flow, which serves as a force for pushing the rotor blade 01 in the direction opposite to the forward direction, which increases the resistance. However, the resistance coefficient Cd is 1 or 2. However, in the case of the present embodiment shown in FIG. 4 (A), since the outer portion of the wedge 3 is rounded in the flow direction to have a smooth shape, the resistance coefficient Cd during forward flight is 0. The winglet vortex reducing device that has been conventionally used to reduce the wingtip vortex 7 such as the winglet wing 05 and the dihedral blade 04 during forward flight causes an increase in resistance. Can be avoided.

[0024]

As described above, according to the blade tip vortex reducing device of the present invention, the structure shown in the claims makes it possible to
The following effects are obtained.

(1) The swirling flow of the spiral vortex of the tip vortex can be significantly attenuated by efficiently hitting the inner surface of the wedge where the rear of the wedge is inclined to open outward. It is possible to suppress a decrease in lift due to the interference between the tip vortex and the blade and an increase in the resistance acting on the blade.

(2) When the blade is a rotor which rotates around the rotor rotation axis, (a) the swirling flow of the spiral vortex, which is damped by colliding with the inner surface of the wedge, reacts with the rotor blade. Generates rotational force,
As a result, the rotating torque of the rotor blades can be reduced and the rotor efficiency can be increased. (B) Further, since the inner side surface is mounted so as to be inclined, it is possible to eliminate an increase in resistance during forward flight such as the dihedral blade or the winglet blade. (C) Furthermore, it is possible to reduce noise due to the interference between the blade tip vortex and the rotating blade, and improve the aerodynamic performance to significantly improve the hovering performance.

[Brief description of drawings]

FIG. 1 is a plan view of a helicopter rotor equipped with an embodiment of a blade tip vortex reducer of the present invention.

2 is an enlarged view of a blade tip portion of the rotary blade shown in FIG.
2A is a perspective view, FIG. 2B is a plan view, and FIG.
Is a front view

FIG. 3 is a diagram showing a state of a tip vortex, and FIG.
FIG. 3B is a diagram showing a state of a blade tip vortex when the embodiment shown in FIG. 3 is provided, and FIG. 3B is a diagram showing a state of a blade tip vortex when only a rectangular blade is used.

FIG. 4 is a diagram showing a flow of wind flowing into a rotor blade during forward flight, FIG. 4 (A) is a diagram showing a flow when the embodiment is provided in FIG. 1, and FIG. 4 (B) is a winglet. FIG. 4 (C) is a diagram showing the flow when the wing is provided, and FIG. 4 (C) is a diagram showing the flow when the dihedral blade is provided.

5A and 5B are views showing a conventional rectangular wing, in which FIG. 5A is a plan view and FIG. 5B is a front view.

6A and 6B are views showing a conventional tapered blade, in which FIG. 6A is a plan view and FIG. 6B is a front view.

7A and 7B are views showing a rotary blade including a conventional dihedral blade, FIG. 7A being a plan view and FIG. 7B being a front view.

8 is a view showing a conventional winglet-equipped wing shown in FIG.
8A is a plan view and FIG. 8B is a front view.

[Explanation of symbols]

 1 Rotor blade as a blade 2 Blade tip 3 Wedge 4 Inner side surface 5 Rear end 6 Outer side surface 7 Blade tip vortex 8 Diffusive flow 9 Force acting on wedge 10 Rotational force 11 Wind

Claims (1)

[Claims] 1. A wedge having a rear end arranged rearward of a rear edge of a blade for generating lift and having an inclined inner side surface for expanding the rear outward with respect to a traveling direction of the blade, A blade tip vortex reducing device, which is vertically provided on a lower surface of a blade tip portion of the blade.