The widespread use of unmanned aerial vehicles poses the task of ensuring their low noise. To solve the problem of designing low-noise unmanned aerial vehicles, it is necessary to have data on the structure of the sound field of various unmanned aerial vehicles and their main noise sources. The results of an acoustic characteristics study of an unmanned aerial vehicle are presented. Its power plant includes a two-stroke piston engine and 4-bladed shrouded pusher propeller. The tests were performed in a wind tunnel at different speeds of the incident flow and different power conditions of the power plant. The dominant source of drone noise is a two-stroke piston engine. The propeller contribution is observed in the second and fourth tones in the radiation spectrum.