// 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()
double alpha;
double de;
double eta_ref_wing = 0.08; // eta of iced data used for curve fit
- double eta_ref_tail = 0.12;
+ 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 KCm_de;
double KCh;
double CL_diff;
+ double CD_diff;
- alpha = Alpha*RAD_TO_DEG;
+ 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));
+ 4.0859e-5*pow(alpha,3));
}
else
{
}
KCL = -delta_CL/eta_ref_wing;
eta_wing = 0.5*(eta_wing_left + eta_wing_right);
- delta_CL = eta_wing*KCL;
+ 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));
+ -4.7511e-5*pow(alpha,3) + 2.3384e-6*pow(alpha,4));
KCD = -delta_CD/eta_ref_wing;
delta_CD = eta_wing*KCD;
- 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));
+ - 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;
// 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));
- }
+ {
+ 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_a = 0;
+ }
delta_Ch_e = -0.0011851 - 0.00049924*de;
delta_Ch = -(delta_Ch_a + delta_Ch_e);
KCh = -delta_Ch/eta_ref_tail;
// rolling moment
CL_diff = (eta_wing_left - eta_wing_right)*KCL;
- delta_Cl = CL_diff/4;
+ 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()
{
- CL_clean = -1*CZ*cos(Alpha) + CX*sin(Alpha); //Check later
- CD_clean = -1*CZ*sin(Alpha) - CX*cos(Alpha);
+ 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;
- CL_iced = CL_clean + delta_CL;
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;
- CL = CL_iced;
CD = CD_iced;
+ CY = CY_iced;
+ CL = CL_iced;
Cm = Cm_iced;
Cl = Cl_iced;
+ Cn = Cn_iced;
//Ch = Ch_iced;
- CZ = -1*CL*cos(Alpha) - CD*sin(Alpha);
- CX = CL*sin(Alpha) - CD*cos(Alpha);
+ 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;
}