Abstract: An experimental study and theoretical analysis on rotor induced sand and dust environment and its harmfulness to helicopter are briefly described in this paper. The experimental study has been made by using a helicopter model which consists of rotor and fuselage models. The induced sand and dust environment is established around the helicopter model hovering at different height near the ground and having different rotor disc loading. The real harm of sand and dust generated by rotor downwash to helicopter was observed and studied. The sand and dust concentration, forces and particle size distribution are measured at some designated locations on (or near) the helicopter. The flow field of the rotor downwash around the helicopter is theoretically analyzed and its velocity is calculated and tested. The law of induced sand and dust concentration, particle size distribution, arid the method of estimating the forces are given from the research results.

Key words: helicopter, rotor, sand and dust