JPH09254894A - Helicopter blade having flap, and rotor control device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the noise and vibration of a helicopter by providing a helicopter blade having a flap capable of remarkably improving the aerodynamic characteristic of the blade even when the flap is small. SOLUTION: When the pitch angle of a flap 12 is reduced in the negative direction, the downward lift is generated on the flap 12, the torsional moment clockwise to the center CA of twist is applied to a blade 11 in which the torsional rigidity is reduced toward a tip part, and the blade 11 is twisted to increase the angle of attach of the blade. When a front edge side of the blade 11 is deformed in the wash-out direction, the pitch angle of the flap 12 is increased in the positive direction, the upward lift is generated on the flap 12, and the torsional moment counterclockwise to the center CA of twist is applied to the blade to reduce the angle of attach of the blade.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helicopter blade with flap and a rotor control device using the same.

[0002]

2. Description of the Related Art Since a helicopter generates various noises and body vibrations, reduction of the noises and body vibrations is a major problem, especially when used as a regular sea route in an urban area.
Noises include main rotor noise, tail rotor noise, BVI (b
lade vortex interaction) noise. Above all, BV
I-noise is caused by the next blade crossing the air vortex created by the preceding blade during rotor rotation, and is greatest when the helicopter descends forward. In addition, the interaction between the rotor and the air causes a large body vibration in the helicopter itself, which causes factors such as deterioration of riding comfort, misidentification of instruments, and metal fatigue.

As a countermeasure for this, a technique called harmonic control (HHC) for controlling the local lift distribution on the rotor rotation surface at a frequency three to six times the rotor rotation frequency is effective, and generally a blade is used. This is achieved by vibrating the pitch angle of itself in a fine cycle. In addition, an IBC (Indivisual Bld) installed on a rotor shaft that rotates an actuator for individually driving the blades.
A control method called ade Control) is also known.

On the other hand, normal helicopter operation is realized by controlling a pitch angle at a blade root of a main rotor via an actuator, a swash plate, a link mechanism and the like.

Since a helicopter rotor is a high-speed rotating object and has a considerably high vibration level, a high-precision mechanism for controlling the pitch angle of the blade is required. In addition, the aerodynamic moment and inertia moment generated around the feathering axis over the entire blade are large, and high-power actuators and hydraulic mechanisms are needed to overcome the mass of the rotor drive mechanism and change the blade pitch angle. Become. This is one reason that it is difficult to reduce the weight of the aircraft.

On the other hand, some prior arts have been proposed in which the torsional rigidity of the blade itself is lowered on the tip side to control the dynamic aerodynamic characteristics of the blade (JP-A-54-54).
20597, U.S. Pat. No. 4,028,003).

On the other hand, some types of so-called active flap systems have been proposed, in which a relatively small flap is attached near the blade tip where the dynamic pressure is sufficiently high, and the large aerodynamic force generated in this portion is used (Japanese Patent Laid-Open No. 6-58242). -10729
3, U.S. Pat. No. 3,077,934, U.S. Pat. No. 3,129.
769, US Pat. No. 3,589,831, US Pat. No. 4
461611, U.S. Pat. No. 5,224,826).
By providing the flap near the blade tip, control is possible with a small steering force, and the overall control mechanism is light and compact.

[0008]

In such a flap drive system, it is required to increase the aerodynamic force generated in the entire blade by a small flap displacement or flap drive force as much as possible.

For example, in JP-A-6-107293,
A wide flap is provided over the entire span on the trailing edge side of a blade having high torsional rigidity, and a high-rigidity blade system is described in which the lift generated in the flap is used as the lift of the blade as it is.

FIG. 8 shows an example of a conventional helicopter blade with flaps. FIG. 8 (a) is a perspective view and FIG. 8 (b) is A.
FIG. 4 is a cross-sectional view taken along a line A. The blade 1 is formed with high torsional rigidity, and the trailing edge of the blade 1 has a length of about 9 from the root portion in the span direction.
Notches for storing flaps are formed over 0%.
The flap 2 is attached to the cutout portion on the trailing edge side of the blade with a variable pitch angle by a hinge or the like. A link member 3 for converting an angular displacement into a linear displacement is provided at the base of the flap 2, and the link member 3 is driven by an actuator 4.

In such a high-rigidity blade system, when the trailing edge of the flap 2 is lowered, the angle of attack of the flap 2 increases and the lift force generated in the flap 2 increases. Blade 1
At the aerodynamic center CA of, the lift of the blade 1 and the lift of the flap 2 are added, and the flap 2 acts to increase the lift of the entire blade. Therefore, in order to increase the total lift, it is necessary to increase the lift of the flap 2, and for this reason, it is essential to increase the area of the flap 2 and increase the output of the flap driving actuator 4.

It is an object of the present invention to provide a helicopter blade with a flap which can significantly improve the aerodynamic characteristics of the blade even with a small flap.

Another object of the present invention is to provide a rotor control device which can reduce noise and vibration of a helicopter by using a helicopter blade with a flap.

[0014]

According to the present invention, there is provided a flap mounted on the trailing edge side of the blade so that the pitch angle is variable, and the torsional rigidity of the blade is formed such that the tip portion is smaller than the root portion. A helicopter blade with a flap, characterized in that the blade is configured to be twisted by the aerodynamic force of the flap. According to the present invention, the aerodynamic force generated in the flap imparts a twisting moment to the blade, and a force of twisting acts on the blade in a direction opposite to the angular displacement direction of the flap. Since the tip has a smaller torsional rigidity than the root, the blade has a larger twisting angle on the tip side of the blade having a higher airspeed, which increases the lift of the blade.
Further, since the aerodynamic force of the flaps is sufficient to sufficiently twist and deform the blade, the aerodynamic characteristics of the blades can be efficiently controlled even with a flap having a small area.
Therefore, the flap and its drive system can be made smaller and lighter, and the flap control can be speeded up.

Further, the present invention is characterized in that the torsional rigidity of the tip portion is formed within the range of 20% to 30% of the torsional rigidity of the root portion. According to the present invention, when a certain twisting moment acts on the blade, the twisting angle of the tip portion increases to about 3 to 5 times that of the root portion. It becomes possible to control the angle of attack that changes greatly toward the side, and as a result, the blade aerodynamic characteristics can be efficiently controlled.

Further, according to the present invention, the blade has a portion in which the torsional rigidity of the blade monotonously decreases from the root portion to the tip portion, and the natural frequency of the blade in the twisting direction is 2.3 to 3.7 cycles /
It is characterized by being within the range of rotation. According to the present invention, the flap pitch angle required when twisting the blade to a constant twist angle is ⅕ of that of the conventional blade (torque direction natural frequency 5.5 cycles / revolution).
It can be reduced to ~ 1 / 2.5. Therefore, the stroke of the flap driving actuator can be similarly reduced, or the flap area can be reduced. for that reason,
As a countermeasure against flap failure, it is easy to multiplex flaps with multiple flaps.

The present invention is also characterized in that the center of twist of the blade is formed so that the tip end is closer to the front edge side than the root part. According to the present invention, the twisting moment generated by the aerodynamic force of the flap is proportional to the distance between the twisting center of the blade and the aerodynamic center of the flap alone, so that the twisting moment increases as the twisting center becomes closer to the blade leading edge side. Therefore, the twisting moment due to the flap becomes larger toward the tip side of the blade, and the twist angle of the blade also becomes larger toward the tip side. As a result, the aerodynamic characteristics of the blade can be efficiently controlled. Further, since the center of torsion is located ahead of the center of aerodynamic force of the blade, the motion of the blade is stabilized, and resonance phenomena such as flutter can be prevented.

According to the present invention, the blade has a flap mounted on the trailing edge side so that the pitch angle is variable, and the torsional rigidity of the blade is formed so that the tip portion is smaller than the root portion. A rotor control device comprising: a helicopter blade configured to impart a torsional deformation to a blade; and a flap drive means for controlling a flap pitch angle. According to the present invention, with respect to the helicopter blade, the twist angle becomes larger toward the blade tip side having a higher airspeed, and the aerodynamic characteristics of the blade can be effectively utilized, as described above.
Further, since the aerodynamic force of the flaps is sufficient to sufficiently twist and deform the blade, the aerodynamic characteristics of the blades can be efficiently controlled even with a flap having a small area.
Therefore, the flap and its drive system can be made smaller and lighter, and the flap control can be speeded up. Further, since the flap driving means controls the pitch angle of the flaps in the stabilizing direction, it is possible to prevent an unstable vibration phenomenon such as flutter due to the low rigidity of the blade. Further, instead of the conventional blade harmonic control for controlling the pitch angle of the entire blade, harmonic control by the flap is performed, whereby the generation of noise and vibration of the helicopter can be efficiently suppressed.

Further, the present invention is characterized in that the flap drive means drives the flap at a frequency of 1 cycle / revolution in order to suppress stall of the backward blade during high speed flight. According to the present invention, during forward flight of the helicopter, the angle of attack at the blade root is small and the angle of attack at the blade tip is negative in the forward blade where the airspeed is maximum. Therefore, in order to reduce the drag force of the blade tip, flap control in the twisting direction is performed so that the angle of attack of the blade tip is as close to zero as possible. On the other hand, in the backward blade where the airspeed is the minimum,
The angle of attack at the root of the blade is greater and the angle of attack at the tip of the blade is greater. Therefore, in order to prevent stall of the blade tip, flap control in the twisting direction is performed so as to reduce the angle of attack of the blade tip. Thus including the forward and backward blades 1
By driving the flaps at a cycle / revolution frequency, the aerodynamic characteristics of the helicopter rotor in one revolution can be greatly improved.

The present invention is also characterized in that the flap driving means drives the flap at a frequency of 2 cycles / rotation in order to increase the lift of the rotor during high speed flight. According to the present invention, it is possible to increase the angle of attack of the blade tips at the front portion and the rear portion of the main rotor that most efficiently generate lift during high-speed flight of the helicopter, so there is concern about stall of the backward blade. It is possible to increase the lift force during high-speed flight without doing so. Further, according to the present invention, in the case of 4 blades, the flap is driven at a frequency of 3 cycles / revolution to 5 cycles / revolution, and in the case of 5 blades, the flap is driven at a frequency of 4 cycles / revolution to 6 cycles / revolution. Since it is driven, the vibration and noise generated by the main rotor can be significantly reduced.

Further, the present invention is characterized in that the helicopter blade is mounted with a variable pitch angle with respect to the rotor shaft, and is provided with blade driving means for controlling the pitch angle of the blade. According to the present invention, since the flap control and the pitch angle control of the blade can be performed independently, it becomes possible to control the twist angle distribution in the blade span direction by a combination of both, and the blade in the entire rotor surface can be controlled. The angle of attack distribution of can be optimized.

Further, the present invention is characterized in that the pitch angle of the root of the blade is constantly increased at the time of hovering, and at the same time, the blade is constantly twisted by flap drive. As a result, the blade can be twisted down by 10 degrees or more, the rotor efficiency at the time of hovering can be increased, and a high lift can be generated.

The present invention is also characterized in that the flap driving means is composed of a smart material that generates mechanical displacement based on an electric signal. According to the present invention, even if the amount of angular displacement of the flap is small, a large torsional moment is generated to control the blade attack angle, so that the actuator for driving the flap can have a small stroke. Therefore, it is possible to reduce the size and weight of the flap drive mechanism by using a smart material having a relatively small stroke, such as a piezoelectric element, a giant magnetostrictive element, or a shape memory alloy, as the flap drive actuator. .

Further, the present invention is characterized in that the flap driving means is multiply equipped on one blade. According to the present invention, since a small flap is driven by a smart material, it is easy to multiplex a flap in which a plurality of flaps are provided on one blade, and even if one flap drive means fails, It becomes possible to back up with the grid.

[0025]

1 shows a helicopter blade with flap which is an embodiment of the present invention. FIG. 1 (a) is a perspective view and FIG. 1 (b) is a sectional view taken along line BB. The blade 11 has an airfoil shape and is formed so that the torsional rigidity is smaller at the tip portion than at the root portion. Blade 11
About 80% of the length in the span direction from the root to the trailing edge
Notches for storing flaps are formed over 90%. The flap 12 has a wing shape, is attached to a notch portion on the blade trailing edge side with a variable pitch angle by a hinge or the like, and is connected to a link member 13 provided at the root of the blade 11 by a rod-shaped connecting member 15. . The link member 13 has a function of converting angular displacement into linear displacement, and when driven by the actuator 14, the flap 12 is angularly displaced via the connecting member 15.

As shown in FIG. 1B, when the actuator 14 raises the trailing edge of the flap 12 to decrease the pitch angle in the negative direction, a downward lift force is generated in the flap 12 to cause the blade 11 to move downward. Has a clockwise torsional moment with respect to the torsion center CA. Then, the blade 11 rises on the front edge side and is deformed in the twisting direction, and the blade attack angle increases.

On the contrary, when the front edge side of the blade 11 is deformed in the twisting direction, when the actuator 14 lowers the rear edge of the flap 12 to increase the pitch angle in the positive direction, the flap 12 is lifted upward. Occurs, a counterclockwise torsion moment acts on the blade 11 with respect to the torsion center CA, and the blade attack angle decreases.

As shown in FIG. 2A, when the torsional moment acting on the blade 11 is constant, the torsional rigidity G
And the torsion angle φ are in inverse proportion to each other, the larger the torsional rigidity G, the smaller the torsion angle φ. As shown in FIG. 2B, when the torsional rigidity of the blade 11 is constant,
Since the area or pitch angle of the flap 12 and the twist angle of the blade 11 are substantially proportional to each other, the larger the area or pitch angle of the flap 12, the larger the twist angle of the blade 11. Also, it can be seen that the smaller the torsional rigidity of the blade 11, the greater the rate of change of the torsion angle.

In the present invention, the torsional rigidity of the blade 11 is made smaller at the tip end portion than at the root portion. Therefore, as shown in FIG. The position in the span direction becomes larger toward the tip side. Since the tip of the blade is where the airspeed is the highest, the effects of the pitch angle and the twist angle are significant. Therefore, in order to greatly control the blade aerodynamic characteristics with a small flap, 1) reduce the torsional rigidity of the blade 11, 2) reduce the torsional rigidity toward the tip side of the blade 11, and 3) change the position of the flap 12 An important point is to bring the blade closer to the tip side.

FIG. 3 is a graph showing the relationship between the torsional natural frequency ratio of the blade and the torsional rigidity. In order to prevent an unstable vibration phenomenon such as flutter, many conventional blades have a torsional natural frequency ratio set in a relatively high region, which is a non-integer multiple of the rotor rotation frequency, for example, 5.5. . Further, conventionally, by forming the entire blade with large torsional rigidity, pitch angle control and harmonic control at the blade root portion can be easily transmitted to the entire blade.

In the present invention, the torsional rigidity of the blade 11 is reduced so that the natural frequency of the blade in the torsional direction is 2.5 to 2.5.
It is set within the range of 3.5 cycles / revolution. As a result, even if the flap 12 is small, the blade 11 is likely to be twisted and deformed, so that a small actuator 14 for driving the flap is sufficient.

FIG. 4 is a graph showing the distribution of the torsional rigidity of the blade 11. FIG. 4A shows an example in which the tip side is lowered to about 1/4 when the root side is set to 1 at the position of about half the position in the span direction of the blade 11. The solid line is an ideal type, and actually has a distribution like a broken line. Figure 4 (b)
Is an example in which the torsional rigidity of the blade 11 is monotonically reduced from the root portion toward the tip portion. FIG. 4 (c)
Is an example in which the torsional rigidity of the blade 11 monotonically decreases from the root portion to the tip portion, and is changed stepwise at about half the position in the span direction. Such a torsional rigidity distribution can be easily realized by appropriately adjusting the density and direction of the fibers when the blade 11 is formed of a composite material in which high-strength fibers such as carbon fibers are combined with a matrix.

By forming such a torsional rigidity distribution, it becomes easy to control the angle of attack of the blade 11, particularly the angle of attack at the tip of the blade 11, and it becomes possible to reduce the size and weight of the flap 12 and its drive system.

Although the unstable vibration phenomenon such as flutter may occur as the torsional rigidity of the blade 11 is reduced, the natural frequency of the blade in the torsional direction is a non-integer multiple of the rotor rotation frequency. Set to, and can be solved by the following method.

FIG. 5 is a sectional view showing the aerodynamic center CA and the torsion center CT of the blade 11. The aerodynamic force generated in the flap 12 is applied to the hinge portion of the flap 12 and the blade 1
The distance L from the torsion center CT of 1 serves as a moment arm, and a torsion moment around the torsion center CT is generated in the blade 11.

In the present invention, the torsion center CT of the blade 11 is used.
Is formed on the front edge side of the aerodynamic center CA, the movement of the blade 11 is also stabilized, and an unstable vibration phenomenon such as flutter can be prevented. The aerodynamic center CA of the blade 11
Is often formed at a position of about 25% from the front edge side with respect to the entire width of the blade 11, and therefore the twist center CT is preferably formed at a position of 15% to 20% from the front edge side. In this case, the twisting moment by the flap 12 is increased by 1.2 to 1.3 times as compared with a normal blade whose twist center is substantially coincident with the aerodynamic center.

FIG. 6 is a plan view showing the distribution of the twist center positions of the blade. In FIG. 6 (a), the position of the center of torsion CT is formed so that the tip portion is closer to the front edge side than the root portion of the blade 11, and particularly about 70% of the position in the span direction.
The distance between the torsion center CT and the aerodynamic center CA on the tip side suddenly increases. Also. The flap 12 is provided on the trailing edge side of the tip of the blade 11. With this arrangement, the twisting moment of the flap 12 increases toward the tip of the blade, and the twisting angle of the blade 11 increases toward the tip. As a result, the aerodynamic characteristics of the blade 11 can be efficiently controlled.

In FIG. 6B, the distance between the torsion center CT and the aerodynamic center CA monotonically increases so as to be substantially proportional to the position in the span direction. In FIG. 6C, the torsion center CT is advanced in the range of 50% to 80% of the position in the span direction, and is returned to the original position on the tip side from 80%. This is because the rotor balance weight 16 is housed at the tip of the blade 11 to increase the strength of the blade tip.

The position distribution of the torsion center CT can be easily adjusted by appropriately adjusting the fiber density and direction when the blade 11 is made of a composite material in which a high strength fiber such as carbon fiber is combined with a matrix. realizable.

FIG. 7 is a block diagram of a rotor control device according to another embodiment of the present invention. The blade 11 and the flap 12 have the same configuration as that of FIG. 1, and the blade 11 is provided with a torsion angle sensor 17 such as a strain gauge for detecting the torsion angle. Torsion angle sensor 17
The output from is transmitted through the wiring in the blade 11 and is taken into the control computer 18 such as a computer. The control computer 18 compares the twist angle of the blade 11 with a reference value, and controls the actuator 14 for driving the flap so that the twist angle of the blade 11 does not exceed the limit due to flutter or the like.

On the other hand, the blade 11 is a rotor shaft (not shown).
It is attached to the actuator 2 with a variable pitch angle.
Driven by 0. The control computer 18 individually drives the actuators 14 and 20 based on the rotor rotation angle signal from the rotor rotation angle sensor 19 to cause the flap 12 to rotate.
And the pitch angle of the blade 11 is controlled independently.

For example, in the forward flight of a helicopter,
In order to reduce the drag of the blade tip of the advancing blade having the maximum airspeed, flap control in the twisting direction is performed so that the angle of attack of the blade tip is as close to zero as possible.

On the other hand, in the retreat side blade having the minimum airspeed, in order to prevent the stall of the tip of the blade,
Flap control in the twisting direction is performed so as to reduce the angle of attack of the blade tip.

By driving the flap at a frequency of 1 cycle / revolution including the forward blade and the backward blade, the aerodynamic characteristics of the helicopter rotor in one revolution can be greatly improved.

FIG. 9 shows the angle of attack distribution of the main rotor when the helicopter is flying at high speed. The lift of the main rotor during forward flight is the front part (near 180) and the rear part (n = ψ).
It can be seen that this occurs at about = 0 °). Therefore, by controlling the flap of the blade at a cycle of 2 cycles / rotation and increasing the angle of attack at the front portion and the rear portion of the main rotor, the aerodynamic characteristics during high-speed flight can be greatly improved.

In addition to the blade attack angle control by the flap, it is also possible to perform the harmonic control or IBC by the flap, whereby the noise and vibration of the helicopter can be reduced.

FIG. 10 shows that the hovering main rotor efficiency is improved by adding blade twist down.

In the configuration of FIG. 7, it is possible to extend the actuator 20 to increase the pitch angle of the blade root, and to contract the actuator 14 to twist down the blade tip, which improves the main rotor efficiency during hovering. .

In the above description, as the flap drive mechanism, an example of the link mechanism of the connecting member 15, the link member 13 and the actuator 14 has been shown. It is also possible to incorporate a giant magnetostrictive element, a shape memory alloy, etc. in the blade 11 and drive the flap 12 directly, whereby the size and weight of the entire apparatus can be reduced.

FIG. 11 shows flaps 21 and 2 divided into three pieces.
It is a block diagram when actuators 2, 32 and 33 using smart materials and control computers 41, 42 and 43 respectively drive them independently. Since the three flaps are independently controlled, even if the flap driving means of one system fails, it is possible to back up the other flaps.

[0051]

As described above in detail, according to the present invention, even if the flap has a small area, the blade attack angle can be easily controlled and the blade aerodynamic characteristics can be efficiently controlled. The size and weight can be reduced, and the flap control speed can be increased.

Further, it becomes possible to control the angle of attack that changes greatly toward the tip of the blade while keeping the strength of the blade sufficiently high, and the blade aerodynamic characteristics can be efficiently controlled.

Further, the flap control can prevent an unstable vibration phenomenon such as flutter due to the reduction of the rigidity of the blade, and the harmonic control or IBC by the flap can be performed to reduce the noise of the helicopter. Vibration can be suppressed efficiently.

Further, by improving the efficiency of flap control,
It is possible to use a small and lightweight smart material as a flap drive mechanism. It is also possible to equip several small flaps with multiplex.

[Brief description of drawings]

FIG. 1 shows a helicopter blade with flap which is an embodiment of the present invention, FIG. 1 (a) is a perspective view, and FIG. 1 (b).
FIG. 4 is a sectional view taken along line BB.

FIG. 2 (a) is a graph showing the relationship between the torsional rigidity G and the torsional angle φ when the torsional moment is constant.
FIG. 2B is a graph showing the relationship between the flap area or pitch angle and the blade twist angle when the blade torsional rigidity is constant, and FIG. 2C shows the twist angle at the blade span position. It is a graph.

FIG. 3 is a graph showing a relationship between a torsional natural frequency ratio of a blade and a torsional rigidity.

FIG. 4 is a graph showing a distribution of torsional rigidity of the blade 11.

FIG. 5 is a cross-sectional view showing the relationship between the center of twist of the blade, the center of aerodynamic force, the lift due to the flap, the lift of the entire blade and the twisting moment generated in the blade.

FIG. 6 is a plan view showing a distribution of twist center positions of a blade.

FIG. 7 is a configuration diagram of a rotor control device according to another embodiment of the present invention, in which 17 is a torsion angle sensor, 20 is an actuator for changing the pitch angle of the blade, and 14 is a flap drive actuator.

8A and 8B are diagrams showing an example of a conventional helicopter blade with a flap, FIG. 8A being a perspective view and FIG. 8B being A-.
FIG. 3 is a sectional view taken along line A.

FIG. 9 is a diagram showing an attack angle distribution of the main rotor during high-speed flight.

FIG. 10 is a graph showing that rotor efficiency during hover is improved by increasing the blade twist angle.

FIG. 11 is a configuration diagram of a rotor control device according to another embodiment of the present invention, showing a triple-system multiplexed flap drive means.

[Explanation of symbols]

 11 Blade 12 Flap 13 Link Member 14, 20 Actuator 15 Connecting Member 16 Weight 17 Torsional Angle Sensor 18 Control Calculator 19 Rotor Rotation Angle Sensor

Claims (11)

[Claims] 1. A blade having a flap mounted on the trailing edge side of the blade with a variable pitch angle, wherein the torsional rigidity of the blade is formed such that the tip portion is smaller than the root portion, and the blade is twisted by the aerodynamic force of the flap. A helicopter blade with a flap, which is configured to be deformed. 2. The helicopter blade with flap according to claim 1, wherein the torsional rigidity of the tip portion is formed within the range of 20% to 30% of the torsional rigidity of the root portion. 3. The blade has a portion where the torsional rigidity monotonically decreases from the root portion toward the tip portion, and the natural frequency of the blade in the torsional direction is within a range of 2.3 to 3.7 cycles / revolution. The helicopter blade with flap according to claim 1 or 2. 4. The helicopter blade with flap according to claim 1, wherein the center of twist of the blade is formed so that the tip end portion is closer to the front edge side than the root portion. 5. A blade having a flap mounted on the trailing edge side of the blade with a variable pitch angle, the torsional rigidity of the blade being formed such that the tip portion is smaller than the root portion. A rotor control device comprising: a helicopter blade configured to impart a torsional deformation; and a flap drive means for controlling a flap pitch angle. 6. The rotor control device according to claim 5, wherein the flap drive means drives the flap at a frequency of 1 cycle / revolution in order to suppress stall of the backward blade during high speed flight. 7. The flap drive means drives the flap at a frequency of 2 cycles / revolution to increase lift of the main rotor during high speed flight, and 3 cycles / revolution to 6 to reduce vibration and noise. 6. The rotor control device according to claim 5, wherein the flap is driven at a cycle / rotation frequency. 8. The rotor control device according to claim 5, wherein the helicopter blade is attached to the rotor shaft in a variable pitch angle, and is provided with blade driving means for controlling the pitch angle of the blade. 9. The rotor control device according to claim 8, wherein a high lift is generated during hovering, so that the pitch angle of the root of the blade is increased in a steady state and at the same time, the blade tip is constantly twisted down by flap drive. . 10. The rotor control device according to claim 5, wherein the flap driving means is composed of a smart material that generates a mechanical displacement based on an electric signal. 11. The rotor control device according to claim 10, wherein the flap drive means is multiply mounted on one blade so that a failure of one system does not affect the other.