-// SIS Twin Otter Iced aircraft Nonlinear model\r
-// Version 020409\r
-// read readme_020212.doc for information\r
-\r
-#include "uiuc_iced_nonlin.h"\r
-\r
-void Calc_Iced_Forces()\r
- {\r
- // alpha in deg\r
- double alpha;\r
- double de;\r
- double eta_ref_wing = 0.08; // eta of iced data used for curve fit\r
- double eta_ref_tail = 0.12;\r
- double eta_wing;\r
- //double delta_CL; // CL_clean - CL_iced;\r
- //double delta_CD; // CD_clean - CD_iced;\r
- //double delta_Cm; // CM_clean - CM_iced;\r
- double delta_Cm_a; // (Cm_clean - Cm_iced) as a function of AoA;\r
- double delta_Cm_de; // (Cm_clean - Cm_iced) as a function of de;\r
- double delta_Ch_a;\r
- double delta_Ch_e;\r
- double KCL;\r
- double KCD;\r
- double KCm_alpha;\r
- double KCm_de;\r
- double KCh;\r
- double CL_diff;\r
- \r
- \r
- \r
- alpha = Alpha*RAD_TO_DEG;\r
- de = elevator*RAD_TO_DEG;\r
- // lift fits\r
- if (alpha < 16)\r
- {\r
- delta_CL = (0.088449 + 0.004836*alpha - 0.0005459*alpha*alpha +\r
- 4.0859e-5*pow(alpha,3));\r
- }\r
- else\r
- {\r
- delta_CL = (-11.838 + 1.6861*alpha - 0.076707*alpha*alpha +\r
- 0.001142*pow(alpha,3));\r
- }\r
- KCL = -delta_CL/eta_ref_wing;\r
- eta_wing = 0.5*(eta_wing_left + eta_wing_right);\r
- delta_CL = eta_wing*KCL;\r
- \r
- \r
- // drag fit\r
- delta_CD = (-0.0089 + 0.001578*alpha - 0.00046253*pow(alpha,2) +\r
- -4.7511e-5*pow(alpha,3) + 2.3384e-6*pow(alpha,4));\r
- KCD = -delta_CD/eta_ref_wing;\r
- delta_CD = eta_wing*KCD;\r
- \r
- // pitching moment fit\r
- delta_Cm_a = (-0.01892 - 0.0056476*alpha + 1.0205e-5*pow(alpha,2)\r
- - 4.0692e-5*pow(alpha,3) + 1.7594e-6*pow(alpha,4));\r
- \r
- delta_Cm_de = (-0.014928 - 0.0037783*alpha + 0.00039086*pow(de,2)\r
- - 1.1304e-5*pow(de,3) - 1.8439e-6*pow(de,4));\r
- \r
- delta_Cm = delta_Cm_a + delta_Cm_de;\r
- KCm_alpha = delta_Cm_a/eta_ref_wing;\r
- KCm_de = delta_Cm_de/eta_ref_tail;\r
- delta_Cm = (0.75*eta_wing + 0.25*eta_tail)*KCm_alpha + (eta_tail)*KCm_de;\r
- \r
- // hinge moment\r
- if (alpha < 13)\r
- {\r
- delta_Ch_a = (-0.0012862 - 0.00022705*alpha + 1.5911e-5*pow(alpha,2)\r
- + 5.4536e-7*pow(alpha,3));\r
- }\r
- else\r
- {\r
- delta_Ch_a = 0;\r
- }\r
- delta_Ch_e = -0.0011851 - 0.00049924*de;\r
- delta_Ch = -(delta_Ch_a + delta_Ch_e);\r
- KCh = -delta_Ch/eta_ref_tail;\r
- delta_Ch = eta_tail*KCh;\r
- \r
- // rolling moment\r
- CL_diff = (eta_wing_left - eta_wing_right)*KCL;\r
- delta_Cl = CL_diff/4;\r
- \r
- }\r
-\r
-void add_ice_effects()\r
-{\r
- CL_clean = -1*CZ*cos(Alpha) + CX*sin(Alpha); //Check later\r
- CD_clean = -1*CZ*sin(Alpha) - CX*cos(Alpha);\r
- Cm_clean = Cm;\r
- Cl_clean = Cl;\r
- Ch_clean = Ch;\r
-\r
- CL_iced = CL_clean + delta_CL;\r
- CD_iced = CD_clean + delta_CD;\r
- Cm_iced = Cm_clean + delta_Cm;\r
- Cl_iced = Cl_clean + delta_Cl;\r
- //Ch_iced = Ch_clean + delta_Ch;\r
-\r
- CL = CL_iced;\r
- CD = CD_iced;\r
- Cm = Cm_iced;\r
- Cl = Cl_iced;\r
- //Ch = Ch_iced;\r
-\r
- CZ = -1*CL*cos(Alpha) - CD*sin(Alpha);\r
- CX = CL*sin(Alpha) - CD*cos(Alpha);\r
-\r
-}\r
+// SIS Twin Otter Iced aircraft Nonlinear model
+// Version 020409
+// read readme_020212.doc for information
+
+// 11-21-2002 (RD) Added e code from Kishwar to fix negative lift problem at
+// high etas
+
+#include "uiuc_iced_nonlin.h"
+
+void Calc_Iced_Forces()
+ {
+ // alpha in deg
+ double alpha;
+ double de;
+ double eta_ref_wing = 0.08; // eta of iced data used for curve fit
+ double eta_ref_tail = 0.20; //changed from 0.12 10-23-2002
+ double eta_wing;
+ double e;
+ //double delta_CL; // CL_clean - CL_iced;
+ //double delta_CD; // CD_clean - CD_iced;
+ //double delta_Cm; // CM_clean - CM_iced;
+ double delta_Cm_a; // (Cm_clean - Cm_iced) as a function of AoA;
+ double delta_Cm_de; // (Cm_clean - Cm_iced) as a function of de;
+ double delta_Ch_a;
+ double delta_Ch_e;
+ double KCL;
+ double KCD;
+ double KCm_alpha;
+ double KCm_de;
+ double KCh;
+ double CL_diff;
+ double CD_diff;
+
+
+
+ alpha = Std_Alpha*RAD_TO_DEG;
+ de = elevator*RAD_TO_DEG;
+ // lift fits
+ if (alpha < 16)
+ {
+ delta_CL = (0.088449 + 0.004836*alpha - 0.0005459*alpha*alpha +
+ 4.0859e-5*pow(alpha,3));
+ }
+ else
+ {
+ delta_CL = (-11.838 + 1.6861*alpha - 0.076707*alpha*alpha +
+ 0.001142*pow(alpha,3));
+ }
+ KCL = -delta_CL/eta_ref_wing;
+ eta_wing = 0.5*(eta_wing_left + eta_wing_right);
+ if (eta_wing <= 0.1)
+ {
+ e = eta_wing;
+ }
+ else
+ {
+ e = -0.3297*exp(-5*eta_wing)+0.3;
+ }
+ delta_CL = e*KCL;
+
+
+ // drag fit
+ delta_CD = (-0.0089 + 0.001578*alpha - 0.00046253*pow(alpha,2) +
+ -4.7511e-5*pow(alpha,3) + 2.3384e-6*pow(alpha,4));
+ KCD = -delta_CD/eta_ref_wing;
+ delta_CD = eta_wing*KCD;
+
+ // pitching moment fit
+ delta_Cm_a = (-0.01892 - 0.0056476*alpha + 1.0205e-5*pow(alpha,2)
+ - 4.0692e-5*pow(alpha,3) + 1.7594e-6*pow(alpha,4));
+
+ delta_Cm_de = (-0.014928 - 0.0037783*alpha + 0.00039086*pow(de,2)
+ - 1.1304e-5*pow(de,3) - 1.8439e-6*pow(de,4));
+
+ delta_Cm = delta_Cm_a + delta_Cm_de;
+ KCm_alpha = delta_Cm_a/eta_ref_wing;
+ KCm_de = delta_Cm_de/eta_ref_tail;
+ delta_Cm = (0.75*eta_wing + 0.25*eta_tail)*KCm_alpha + (eta_tail)*KCm_de;
+
+ // hinge moment
+ if (alpha < 13)
+ {
+ delta_Ch_a = (-0.0012862 - 0.00022705*alpha + 1.5911e-5*pow(alpha,2)
+ + 5.4536e-7*pow(alpha,3));
+ }
+ else
+ {
+ delta_Ch_a = 0;
+ }
+ delta_Ch_e = -0.0011851 - 0.00049924*de;
+ delta_Ch = -(delta_Ch_a + delta_Ch_e);
+ KCh = -delta_Ch/eta_ref_tail;
+ delta_Ch = eta_tail*KCh;
+
+ // rolling moment
+ CL_diff = (eta_wing_left - eta_wing_right)*KCL;
+ delta_Cl = CL_diff/8.; // 10-23-02 Previously 4
+
+ //yawing moment
+ CD_diff = (eta_wing_left - eta_wing_right)*KCD;
+ delta_Cn = CD_diff/8.;
+
+ }
+
+void add_ice_effects()
+{
+ CD_clean = -1*CX*Cos_alpha*Cos_beta - CY*Sin_beta - CZ*Sin_alpha*Cos_beta;
+ CY_clean = -1*CX*Cos_alpha*Sin_beta + CY*Cos_beta - CZ*Sin_alpha*Sin_beta;
+ CL_clean = CX*Sin_alpha - CZ*Cos_alpha;
+ Cm_clean = Cm;
+ Cl_clean = Cl;
+ Cn_clean = Cn;
+ Ch_clean = Ch;
+
+ CD_iced = CD_clean + delta_CD;
+ CY_iced = CY_clean;
+ CL_iced = CL_clean + delta_CL;
+ Cm_iced = Cm_clean + delta_Cm;
+ Cl_iced = Cl_clean + delta_Cl;
+ Cn_iced = Cn_clean + delta_Cn;
+ //Ch_iced = Ch_clean + delta_Ch;
+
+ CD = CD_iced;
+ CY = CY_iced;
+ CL = CL_iced;
+ Cm = Cm_iced;
+ Cl = Cl_iced;
+ Cn = Cn_iced;
+ //Ch = Ch_iced;
+
+ CX = -1*CD*Cos_alpha*Cos_beta - CY*Cos_alpha*Sin_beta + CL*Sin_alpha;
+ CY = -1*CD*Sin_beta + CY*Cos_beta;
+ CZ = -1*CD*Sin_alpha*Cos_beta - CY*Sin_alpha*Sin_beta - CL*Cos_alpha;
+
+}
projects / flightgear.git / blobdiff