Mathematical description of the interaction between a probing microwave signal and the helicopter main rotor blade

The paper deals with the non-contact method of monitoring the integrity of the main rotor blades of a helicopter. The available methods of monitoring the integrity of the main rotor blades of the helicopter are labor-intensive to implement, their reliability is low and they do not allow drawing a general picture of the state of rotor blades in flight. To solve this problem a method based on illumination of the blades by a probing microwave signal is proposed. Particular attention is given to the calculation of the power of the signal reflected from the helicopter main rotor blades. In deriving analytic equations it is assumed that a rotor blade is an undeformed flat metal surface. As a result, a spatial-temporal model of a probing SHF signal reflected from a helicopter’s main rotor blade has been obtained and the parameters of the model make it possible to assess the operational status of the main rotor of the helicopter.