Reduction Of High Speed Impulsive Noise By Blade Planform Modification Of A Model Helicopter Rotor

Download or read book Reduction of High-speed Impulsive Noise by Blade Planform Modification of a Model Helicopter Rotor written by David Alan Conner and published by . This book was released on 1982 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experiment has been performed to investigate the reduction of high-speed impulsive noise for the UH-1H helicopter by using an advanced main rotor system. The advanced rotor system had a tapered blade planform compared with the rectangular planform of the standard rotor system. Models of both the advanced main rotor system and the UH-1H standard main rotor system were tested at 1/4 scale in the Langley 4- by 7-Meter Tunnel. In-plane acoustic measurements of the high-speed impulsive noise demonstrated that the advanced rotor system on the UH-1H helicopter reduced the high-speed impulsive noise by up to 20 dB, with a reduction in overall sound pressure level of up to 6 dB. (Author).