Figure 1.
Schematic diagram of the effect of rotor rotation on the helicopter radar cross-section.
Figure 1.
Schematic diagram of the effect of rotor rotation on the helicopter radar cross-section.
Figure 2.
Method flow chart.
Figure 2.
Method flow chart.
Figure 3.
Schematic of the illuminated area change of the helicopter surface when the rotor is rotating.
Figure 3.
Schematic of the illuminated area change of the helicopter surface when the rotor is rotating.
Figure 4.
Validation of the radar cross-section (RCS) algorithm on the tail rotor, fR = 5 GHz, α = 0°~360°, β = 0°, t = 0 s.
Figure 4.
Validation of the radar cross-section (RCS) algorithm on the tail rotor, fR = 5 GHz, α = 0°~360°, β = 0°, t = 0 s.
Figure 5.
Validation of dynamic RCS on the tail rotor, fR = 5 GHz, α = 60°, β = 0°, nr2 = 1500 r/min.
Figure 5.
Validation of dynamic RCS on the tail rotor, fR = 5 GHz, α = 60°, β = 0°, nr2 = 1500 r/min.
Figure 6.
Helicopter model and its main dimensions.
Figure 6.
Helicopter model and its main dimensions.
Figure 7.
Main rotor and tail rotor size distribution.
Figure 7.
Main rotor and tail rotor size distribution.
Figure 8.
Meshing of helicopter and rotor model surfaces.
Figure 8.
Meshing of helicopter and rotor model surfaces.
Figure 9.
Dynamic RCS of the tail rotor at different fR values, α = 0°, β = 0°, nr2 = 1500 r/min.
Figure 9.
Dynamic RCS of the tail rotor at different fR values, α = 0°, β = 0°, nr2 = 1500 r/min.
Figure 10.
Dynamic RCS of the tail rotor at different nr2, fR = 5 GHz, α = 330°, β = 0°, γ = θ = 0°.
Figure 10.
Dynamic RCS of the tail rotor at different nr2, fR = 5 GHz, α = 330°, β = 0°, γ = θ = 0°.
Figure 11.
Dynamic RCS of the tail rotor at different nr1, fR = 5 GHz, α = 330°, β = 0°, γ = θ = 0°.
Figure 11.
Dynamic RCS of the tail rotor at different nr1, fR = 5 GHz, α = 330°, β = 0°, γ = θ = 0°.
Figure 12.
Effect of azimuth on rotor dynamic RCS, fR =5 GHz, β=0°, γ = θ = 0°.
Figure 12.
Effect of azimuth on rotor dynamic RCS, fR =5 GHz, β=0°, γ = θ = 0°.
Figure 13.
Effect of elevation angle on rotor dynamic RCS, fR = 5 GHz, α = 280°, γ = θ = 0°.
Figure 13.
Effect of elevation angle on rotor dynamic RCS, fR = 5 GHz, α = 280°, γ = θ = 0°.
Figure 14.
Effect of pitching angle on surface electromagnetic scattering of the helicopter, nr1 = 500 r/min, nr2 = 1500 r/min, fR = 5 GHz, α = 25°, γ = 0°.
Figure 14.
Effect of pitching angle on surface electromagnetic scattering of the helicopter, nr1 = 500 r/min, nr2 = 1500 r/min, fR = 5 GHz, α = 25°, γ = 0°.
Figure 15.
Effect of pitching angle on helicopter RCS, nr1 = 500 r/min, nr2 = 1500 r/min, fR = 5 GHz, γ = 0°.
Figure 15.
Effect of pitching angle on helicopter RCS, nr1 = 500 r/min, nr2 = 1500 r/min, fR = 5 GHz, γ = 0°.
Figure 16.
Effect of rolling angle on helicopter surface scattering, nr1 = 500 r/min, nr2 = 1500 r/min, fR =5 GHz, α = 30°, β = 0°, θ = −10°.
Figure 16.
Effect of rolling angle on helicopter surface scattering, nr1 = 500 r/min, nr2 = 1500 r/min, fR =5 GHz, α = 30°, β = 0°, θ = −10°.
Figure 17.
Effect of rolling angle on helicopter RCS, nr1 = 500 r/min, nr2 = 1500 r/min, fR = 5 GHz, β = 0°, θ = −10°.
Figure 17.
Effect of rolling angle on helicopter RCS, nr1 = 500 r/min, nr2 = 1500 r/min, fR = 5 GHz, β = 0°, θ = −10°.
Table 1.
The main dimensions of the helicopter model.
Table 1.
The main dimensions of the helicopter model.
Parameter | Lfus/m | Wfus/m | Hfus/m | Xn/m | Zr1/m |
---|
Value | 15.546 | 4.4 | 3.84 | 5.9 | 3.1 |
Parameter | Rr1/m | Rr2/m | Rr1h/m | Xr2/m | Zr2/m |
Value | 5.5 | 1.5 | 0.3 | 9.1 | 2.8 |
Table 2.
The main dimensions of the helicopter model.
Table 2.
The main dimensions of the helicopter model.
Main Rotor | At10/° | At11/° | At12/° | At13/° | Airfoil |
---|
Value | 13 | 5 | 4 | 3 | HD53 |
Tail rotor | At20/° | At21/° | Rr2h/m | Lr2a/m | Airfoil |
Value | 20 | 10 | 0.25 | 0.54 | Dormoy |
Table 3.
RCS mean of the tail rotor at different fR values, α = 0°, β = 0°, nr2 = 1500 r/min.
Table 3.
RCS mean of the tail rotor at different fR values, α = 0°, β = 0°, nr2 = 1500 r/min.
fR/GHz | 1 | 3 | 5 | 7 | 9 | 11 |
Mean RCS/dBm2 | −7.20 | −4.74 | −2.65 | −2.89 | −4.87 | −3.24 |
Table 4.
Effect of azimuth on rotor dynamic RCS mean, fR = 5 GHz, β = 0°, γ = θ = 0°.
Table 4.
Effect of azimuth on rotor dynamic RCS mean, fR = 5 GHz, β = 0°, γ = θ = 0°.
Azimuth/° | 80 | 90 | 100 | 110 | 120 |
Main Rotor/dBm2 | −1.28 | 17.10 | −0.42 | −4.23 | −1.21 |
Tail Rotor/dBm2 | 7.78 | 9.26 | 7.78 | 11.78 | 4.42 |
Table 5.
Effect of elevation angle on rotor dynamic RCS mean, fR = 5 GHz, α = 280°, γ = θ = 0°.
Table 5.
Effect of elevation angle on rotor dynamic RCS mean, fR = 5 GHz, α = 280°, γ = θ = 0°.
β/° | −10 | −5 | 0 | 5 | 10 |
Main Rotor/dBm2 | −9.25 | −4.96 | −1.20 | −0.85 | −4.64 |
Tail Rotor/dBm2 | 7.68 | 4.66 | 4.37 | 4.68 | 6.45 |
Table 6.
Effect of pitching angle on helicopter RCS mean, nr1 = 500 r/min, nr2 = 1500 r/min, fR = 5 GHz, α = 0~360°, γ = β = 0°, t = 0.0177 s.
Table 6.
Effect of pitching angle on helicopter RCS mean, nr1 = 500 r/min, nr2 = 1500 r/min, fR = 5 GHz, α = 0~360°, γ = β = 0°, t = 0.0177 s.
θ/° | −10 | −5 | 0 | 5 | 10 |
RCS Mean/dBm2 | 40.93 | 40.80 | 48.84 | 40.81 | 40.95 |
Table 7.
Effect of rolling angle on helicopter RCS mean, nr1 = 500 r/min, nr2 = 1500 r/min, fR =5 GHz, α = 0~360°, β = 0°, θ = −10°, t = 0.0207 s.
Table 7.
Effect of rolling angle on helicopter RCS mean, nr1 = 500 r/min, nr2 = 1500 r/min, fR =5 GHz, α = 0~360°, β = 0°, θ = −10°, t = 0.0207 s.
γ/° | −20 | −15 | −10 | 0 | 10 | 15 | 20 |
RCS Mean/dBm2 | 10.41 | 21.13 | 14.66 | 40.81 | 11.51 | 21.46 | 11.25 |