抄録
The aircraft and mechanical systems division of Kawada Industries, Inc. has been experimentally researching two different techniques to reduce the BVI noise of helicopter. One is the jet rotor system and the other is the active spoiler system. Regarding the jet rotor system, BVI noise level reduction of 9 dB was achieved through the wind-tunnel test using a model rotor. On the active spoiler system, aerodynamically optimum configuration of the spoiler was determined for the 2D fixed wing with wind-tunnel test so far. This paper explains the concept of both systems and describes those wind-tunnel test results.
