Bvi noise reduction method and apparatus for helicopter

Abstract

The present method is characterized by providing the rotor blade with a tab 3, which can advance and retreat with respect to rear of rotating direction of the rotor blade between a position where the tab protrudes from a trailing edge of the rotor blade and a position where the tab does not, and providing an actuator 4, which advances and retreats the tab 3, and operating the actuator 4 so that the tab advances and retreats in response to rotating timing of the rotor blade 2, when reducing the BVI noise of the rotor blade of a helicopter. Thus, the BVI noise of a helicopter can be reduced effectively.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a method and an apparatus that can be used for reducing BVI (Blade Vortex Interaction) noise generated by rotor blades of a helicopter.BACKGROUND ART[0002]In recent years reduction of a noise of a helicopter is expected, and a method described in Japanese Patent Laid-Open No. 10-271852 bulletin, for example, is known as a measure for the noise reduction. In the technology as described in this bulletin, in order to reduce a noise by decreasing the rotational velocity of a rotor, the aerodynamic characteristic of the rotor blades is improved by providing the trailing edge of the rotor blade with a small flap, whose tilt angle to the rotor blade is controlled precisely by the twist actuator in the rotor blade using a piezoelectric element.[0003]However, the measure using a flap is in practice not so easy, since great control force and high response are required for changing the angle of the flap in the rapidly rotating rotor ...

AI Technical Summary

Benefits of technology

[0007]The present invention provides a BVI noise reduction method and apparatus that has solved a prior-art problem in view of the information described above and the BVI noise reduction method for a helicopter according to the present invention is characterized by, when reducing the BVI noise of the rotor blade of a helicopter, providing the rotor blade with a tab which can advance or retreat with respect to rear of rotating direction between a position where the tab protrudes from a trailing edge of the rotor blade and a position where the tab does not, and also by providing the rotor system including the rotor blade which rotates with respect to a body of the helicopter with an actuator which advances and retreats the tab and operating the actuator so that the tab can advance and retreat in response to the rotating timing of the rotor blade.

[0009]Moreover, since not so big control force is required for such advance and retreat of the tab with respect to rear of rotating direction from the trailing edge of the rotor blade, the actuator which activates the tab can be configured to be small enough to be set in the rotor system, and at the same time high response of the tab can be achieved easily.

Problems solved by technology

However, the measure using a flap is in practice not so easy, since great control force and high response are required for changing the angle of the flap in the rapidly rotating rotor blade.

This fluctuation of pressure distribution causes an impulsive noise which stands out among other noises.

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