Compound helicopter multi-rotor dynamic radar cross section response analysis

X-Band Radar Cross-Section of Tandem Helicopter Based on Dynamic Analysis Approach

“…The helicopter consists of two main rotors and a fuselage; thus, its initial model can be expressed as follows: where t is time, m h is the model of the tandem helicopter, m r1 is the model of rotor 1, m r2 is the model of rotor 2, m f is the model of the fuselage [ 3 , 15 ]. In the current coordinate system, when rotor 1 rotates, its dynamic model can be updated to: where M r1 is the grid coordinate matrix of rotor 1, superscript x represents the translation along the x -axis, superscript xz represents the rotation around the z -axis in the current operation, X r1 is the distance between the axis of rotor 1 and the z -axis in the initial state.…”

“…In order to analyze the dynamic RCS response of a compound helicopter, a multi-rotor, dynamic scattering calculation method is presented [ 15 ]. This processing approach can bring support and reference for the solution of the radar characteristics of the tandem helicopter [ 16 , 17 ].…”

“…A dynamic transformation method based on PO and PTD was established to calculate the electromagnetic scattering characteristics of coaxial helicopters [ 18 ]. When controlling the flight attitude, the tilt angle of the rotor disc will also change the RCS of the helicopter [ 15 , 19 , 20 ]. The difference in structure from conventional unmanned helicopters is that unmanned tandem helicopters have no slender tail boom, with two rotors of the same size arranged in the longitudinal direction, one in the front and one in the back, and the rotors have the same rotation speed and opposite rotation directions [ 21 , 22 , 23 ].…”

Keen Investigation of the Electromagnetic Scattering Characteristics of Tiltrotor Aircraft Based on Dynamic Calculation Method

“…where t c is the tilting time of the cabin, A ct is the final tilt angle of the cabin, ω c is the angular velocity of the cabin. For more information about dynamic scattering calculation methods, please refer to the literature [16,20]. For single or small sample calculations, PO + PTD is feasible and fast.…”

“…Being much larger than the existence of a bird or flying insect, the tiltrotor has a much larger adjustment angle of the rotor disc than a conventional/coaxial helicopter, which will cause its RCS to have a large magnitude and fluctuation at more azimuths [15][16][17]. The multi-rotor dynamic scattering method is presented to evaluate the RCS of the compound helicopter, which guides the calculation of the radar characteristics of the tilt-rotor aircraft [18][19][20]. It can be seen that the radar stealth characteristics of fixed-wing aircraft and helicopters [21][22][23][24] and the aerodynamics and control strategies of tilt-rotor aircraft have received rich research results [25][26][27][28][29], while there is very little work and investigation in the stealth research of tiltrotor aircraft.…”