X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FFDM%2FUIUCModel%2Fuiuc_iced_nonlin.cpp;h=30ac008fa5637fb57fc9a96fe5579e1548abf82d;hb=70b4f38ebccbafea664ed2310eaf990bd2b9edd8;hp=6a215d1a4568660801dd5c7aa60daf5aa8638bc2;hpb=e9dba2caa19746d70bb3f2efc9d718902361ee16;p=flightgear.git

diff --git a/src/FDM/UIUCModel/uiuc_iced_nonlin.cpp b/src/FDM/UIUCModel/uiuc_iced_nonlin.cpp
index 6a215d1a4..30ac008fa 100644
--- a/src/FDM/UIUCModel/uiuc_iced_nonlin.cpp
+++ b/src/FDM/UIUCModel/uiuc_iced_nonlin.cpp
@@ -2,6 +2,9 @@
 //     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()
@@ -10,8 +13,9 @@ 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;
@@ -25,16 +29,17 @@ void Calc_Iced_Forces()
 	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
 		{
@@ -43,12 +48,20 @@ void Calc_Iced_Forces()
 		}
 	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;
 	
@@ -57,7 +70,7 @@ void Calc_Iced_Forces()
 		      - 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;
@@ -66,14 +79,14 @@ void Calc_Iced_Forces()
 	
 	// 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;
@@ -81,31 +94,42 @@ void Calc_Iced_Forces()
 	
 	// 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;
 
 }