Study of aircraft radial piston engines noise

The results of the study of acoustic characteristics of aircraft radial piston engines ASH-62IR and M-14P are presented. The tests were carried out during the race of the power plants of the AN-2 and Yak-18T light propeller-driven aircrafts under static conditions at the local aerodrome. It is shown that the method of organizing the exhaust of a multi-cylinder engine determines the main tone frequency. The influence of the engine power condition on the directivity of the tonal noise components is considered. The dependences of the sound power on the engine speed are obtained.