In the article it is shown, that the basic sources of noise micro pilotless aircraft are the piston engine, the air screw. On the basis of the analysis of existing methods of definition of acoustic characteristics the conclusion is drawn, decision of problems of aviation acoustics is not obviously possible only by theoretical methods because of complexity of processes of formation of noise. It causes necessity of carrying out of experimental researches in laboratory and natural conditions. Results of measurement in natural conditions according to a standard technique of level of not muffled noise of release of the piston engine of micro pilotless aircraft "Strepet M" have well coincided with results of calculation by a semiempirical technique.
aerodynamic noise, the piston engine, the air screw, experimental researches, natural experiment