Abstract: A flow control method is a flow control method of controlling flow around a blade of a rotary wing, a plasma actuator being disposed at the blade. The flow control method includes: determining a characteristic frequency ratio that is a characteristic value among frequency ratios, each of the frequency ratios being a ratio between an actuator driving frequency and an angle of attack changing frequency, the actuator driving frequency being a frequency of an applied voltage applied to the plasma actuator, the angle of attack changing frequency being a frequency at which an angle of attack of the blade changes in accordance with a rotation angle of the blade; setting the actuator driving frequency such that the frequency ratio becomes the characteristic frequency ratio; and applying a voltage of the set actuator driving frequency to the plasma actuator to control the flow around the blade.

Abstract: A flow control method is a flow control method of controlling flow around a blade of a rotary wing, a plasma actuator being disposed at the blade. The flow control method includes: determining a characteristic frequency ratio that is a characteristic value among frequency ratios, each of the frequency ratios being a ratio between an actuator driving frequency and an angle of attack changing frequency, the actuator driving frequency being a frequency of an applied voltage applied to the plasma actuator, the angle of attack changing frequency being a frequency at which an angle of attack of the blade changes in accordance with a rotation angle of the blade; setting the actuator driving frequency such that the frequency ratio becomes the characteristic frequency ratio; and applying a voltage of the set actuator driving frequency to the plasma actuator to control the flow around the blade.

Abstract: A flow control method is a flow control method of controlling flow around a blade of a rotary wing, a plasma actuator being disposed at the blade. The flow control method includes: determining a characteristic frequency ratio that is a characteristic value among frequency ratios, each of the frequency ratios being a ratio between an actuator driving frequency and an angle of attack changing frequency, the actuator driving frequency being a frequency of an applied voltage applied to the plasma actuator, the angle of attack changing frequency being a frequency at which an angle of attack of the blade changes in accordance with a rotation angle of the blade; setting the actuator driving frequency such that the frequency ratio becomes the characteristic frequency ratio; and applying a voltage of the set actuator driving frequency to the plasma actuator to control the flow around the blade.

Abstract: A rotary-wing aircraft blade airfoil for use with a rotary-wing aircraft such as a helicopter. The airfoil satisfies the following four conditions: a first condition in which a blade thickness has its maximum value at a position within a range from 30% chord to 40% chord; a second condition in which a camber has its maximum value at a position within a range from 15% chord to 25% chord, and that a slope of the camber changes from decreasing into increasing at a position within a range from 45% chord to 55% chord; a third condition in which the upper blade height has its maximum value at a position within a range from 25% chord to 35% chord; and a fourth condition in which the lower blade height has its maximum value at a position within a range from 35% chord to 45% chord.

Abstract: Image signals outputted from a CCD to an image signal processing circuit, which performs A/D conversion, YC signal processing to convert the image signals into video signals of NTSC or the like and outputs video signals after D/A conversion. A microcomputer receives the video signals from the image signal processing circuit and determines a brightness level of the video signals. An EEPROM stores a data table showing the relationship between a correction amount and the brightness level, and the microcomputer obtains the correction amount from the EEPROM. The microcomputer corrects the video signals according to the correction amount before the D/A conversion, and the image signal processing circuit outputs the corrected video signals to a displaying device controlling circuit, and a displaying device displays an image.

Abstract: Image signals outputted from a CCD to an image signal processing circuit, which performs A/D conversion, YC signal processing to convert the image signals into video signals of NTSC or the like and outputs video signals after D/A conversion. A microcomputer receives the video signals from the image signal processing circuit and determines a brightness level of the video signals. An EEPROM stores a data table showing the relationship between a correction amount and the brightness level, and the microcomputer obtains the correction amount from the EEPROM. The microcomputer corrects the video signals according to the correction amount before the D/A conversion, and the image signal processing circuit outputs the corrected video signals to a displaying device controlling circuit, and a displaying device displays an image.