Ground Resonance Inherent in a Coaxial Helicopter

This paper is devoted to analyzing ground resonance phenomenon inherent in a light helicopter of a pine-shaped design, characterized by two pairs of blades rotating in opposite directions around the same axis. A single-seat MICRON-type helicopter, developed by Russian designers, has been used as a basis. By using Bogolyubov’s averaging method, the potentialities of resonance onset have been demonstrated and instability regions have been found.