Flight Test Noise Measurements Of A UH-1B Helicopter

A noise measurement test of a UH-1B helicopter has been conducted by USAAVLABS in conjunction with other noise research presently being studied. The. test was performed at Wallops Island with the cooperation of NASA-Langley Research Center. The original objective of the program was to study the noise characteristics of the UH-1B helicopter. Special emphasis, however, was placed on gaining some insight into and understanding of the various forms in which reduced data can be represented. To satisfy the objectives of this test program, several types of data reduction and analysis were investigated. Plots of sound pressure level ersus frequency (SPL plots) were obtained using oth constant bandwidth and constant percentage bandwidth analyzers. Both of these analyzers were useful in defining the shape of the noise spectrum in great detail. In addition, real time analysis was performed on the data as an out-of-house effort.