About the direction of acoustic radiation of propeller power plant

Abstract

The paper summarizes the experimental data on the acoustic radiation pattern piston power plants, used on aircraft such as airplane. Acoustic testing of light aircraft An-2, Yak-18T, MAI-223M, MAI-890, MAI-890U and F30 were performed at the aerodrome of the Moscow Aviation Institute. There have also been carried out acoustic testing small-size unmanned aircraft with piston engine in an anechoic chamber AK-2 TsAGI. It is shown that when the of the power plant on the takeoff in the rear hemisphere in the areas of 105-120 ° in the total noise of the power plant is dominated by radiation at a frequency of rotation of the first propeller noise harmonics. On the crankshaft axis is dominant acoustic radiation from the piston engine. Factors obtained the total directivity of acoustic radiation of power plant and its separate components, which will be used in the calculation of community noise of light aircraft and small-sized unmanned aerial vehicles.