latest updates from JSBSim

diff --git a/src/FDM/JSBSim/models/FGAircraft.cpp b/src/FDM/JSBSim/models/FGAircraft.cpp
index 30649c6a42337b638b27a150219328983b4a9ad1..e2adbe44cd2f83cba7493f22292211a9cb335a2a 100644 (file)
--- a/src/FDM/JSBSim/models/FGAircraft.cpp
+++ b/src/FDM/JSBSim/models/FGAircraft.cpp
@@ -67,7 +67,7 @@ DEFINITIONS
 GLOBAL DATA
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-static const char *IdSrc = "$Id: FGAircraft.cpp,v 1.29 2010/11/18 12:38:06 jberndt Exp $";
+static const char *IdSrc = "$Id: FGAircraft.cpp,v 1.30 2010/11/29 12:33:57 jberndt Exp $";
 static const char *IdHdr = ID_AIRCRAFT;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -153,7 +153,7 @@ bool FGAircraft::Run(void)
 double FGAircraft::GetNlf(void) const
 {
   if (FDMExec->GetMassBalance()->GetWeight() != 0)
-  return (-FDMExec->GetAerodynamics()->GetvFw(3))/FDMExec->GetMassBalance()->GetWeight();
+    return (-FDMExec->GetAerodynamics()->GetvFw(3))/FDMExec->GetMassBalance()->GetWeight();
   else
     return 0.;
 }

diff --git a/src/FDM/JSBSim/models/FGAtmosphere.cpp b/src/FDM/JSBSim/models/FGAtmosphere.cpp
index d2c6a3dac1adee4f3d40882e790c962da3c49388..f40fabcb5e00c77d85cbc5042bd013eb33ae5233 100644 (file)
--- a/src/FDM/JSBSim/models/FGAtmosphere.cpp
+++ b/src/FDM/JSBSim/models/FGAtmosphere.cpp
@@ -61,7 +61,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGAtmosphere.cpp,v 1.40 2010/11/18 12:38:06 jberndt Exp $";
+static const char *IdSrc = "$Id: FGAtmosphere.cpp,v 1.41 2010/11/30 12:19:57 jberndt Exp $";
 static const char *IdHdr = ID_ATMOSPHERE;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -572,8 +572,11 @@ void FGAtmosphere::Turbulence(void)
   }
   case ttMilspec:
   case ttTustin: {
+    double V = FDMExec->GetAuxiliary()->GetVt(); // true airspeed in ft/s
+
     // an index of zero means turbulence is disabled
-    if (probability_of_exceedence_index == 0) {
+    // airspeed occurs as divisor in the code below
+    if (probability_of_exceedence_index == 0 || V == 0) {
       vTurbulenceNED(1) = vTurbulenceNED(2) = vTurbulenceNED(3) = 0.0;
       vTurbPQR(1) = vTurbPQR(2) = vTurbPQR(3) = 0.0;
       return;
@@ -582,10 +585,11 @@ void FGAtmosphere::Turbulence(void)
     // Turbulence model according to MIL-F-8785C (Flying Qualities of Piloted Aircraft)
     double
       h = FDMExec->GetPropagate()->GetDistanceAGL(),
-      V = FDMExec->GetAuxiliary()->GetVt(), // true airspeed in ft/s
       b_w = wingspan,
       L_u, L_w, sig_u, sig_w;
 
+      if (b_w == 0.) b_w = 30.;
+
     // clip height functions at 10 ft
     if (h <= 10.) h = 10;
 
@@ -644,6 +648,10 @@ void FGAtmosphere::Turbulence(void)
         C_BLq = 1/tau_q/tan(T_V/2/tau_q), // eq. (24)
         C_BLr = 1/tau_r/tan(T_V/2/tau_r); // eq. (26)
 
+      // all values calculated so far are strictly positive, except for
+      // the random numbers nu_*. This means that in the code below, all
+      // divisors are strictly positive, too, and no floating point
+      // exception should occur.
       xi_u = -(1 - C_BL*tau_u)/(1 + C_BL*tau_u)*xi_u_km1
            + sig_u*sqrt(2*tau_u/T_V)/(1 + C_BL*tau_u)*(nu_u + nu_u_km1); // eq. (18)
       xi_v = -2*(sqr(omega_v) - sqr(C_BL))/sqr(omega_v + C_BL)*xi_v_km1

diff --git a/src/FDM/JSBSim/models/propulsion/FGPiston.cpp b/src/FDM/JSBSim/models/propulsion/FGPiston.cpp
index b225563c2e0a4516da20e9483e2afdd05eb3d193..522a0b2fea57b10e41b7345b1fb6833559cae5c4 100644 (file)
--- a/src/FDM/JSBSim/models/propulsion/FGPiston.cpp
+++ b/src/FDM/JSBSim/models/propulsion/FGPiston.cpp
@@ -53,7 +53,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGPiston.cpp,v 1.53 2010/08/21 17:13:48 jberndt Exp $";
+static const char *IdSrc = "$Id: FGPiston.cpp,v 1.54 2010/11/30 12:17:10 jberndt Exp $";
 static const char *IdHdr = ID_PISTON;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -92,13 +92,14 @@ FGPiston::FGPiston(FGFDMExec* exec, Element* el, int engine_number)
   Bore = 5.125;
   Stroke = 4.375;
   Cylinders = 4;
+  CylinderHeadMass = 2; //kg
   CompressionRatio = 8.5;
   Z_airbox = -999;
   Ram_Air_Factor = 1;
   PeakMeanPistonSpeed_fps = 100;
   FMEPDynamic= 18400;
   FMEPStatic = 46500;
-
+  Cooling_Factor = 0.5144444;
 
   // These are internal program variables
 
@@ -200,10 +201,14 @@ FGPiston::FGPiston(FGFDMExec* exec, Element* el, int engine_number)
     Stroke = el->FindElementValueAsNumberConvertTo("stroke","IN");
   if (el->FindElement("cylinders"))
     Cylinders = el->FindElementValueAsNumber("cylinders");
+  if (el->FindElement("cylinder-head-mass"))
+    CylinderHeadMass = el->FindElementValueAsNumberConvertTo("cylinder-head-mass","KG");
   if (el->FindElement("air-intake-impedance-factor"))
     Z_airbox = el->FindElementValueAsNumber("air-intake-impedance-factor");
   if (el->FindElement("ram-air-factor"))
     Ram_Air_Factor  = el->FindElementValueAsNumber("ram-air-factor");
+  if (el->FindElement("cooling-factor"))
+    Cooling_Factor  = el->FindElementValueAsNumber("cooling-factor");
   if (el->FindElement("dynamic-fmep"))
     FMEPDynamic= el->FindElementValueAsNumberConvertTo("dynamic-fmep","PA");
   if (el->FindElement("static-fmep"))
@@ -303,8 +308,12 @@ FGPiston::FGPiston(FGFDMExec* exec, Element* el, int engine_number)
   PropertyManager->Tie(property_name, &Z_airbox);
   property_name = base_property_name + "/ram-air-factor";
   PropertyManager->Tie(property_name, &Ram_Air_Factor);
+  property_name = base_property_name + "/cooling-factor";
+  PropertyManager->Tie(property_name, &Cooling_Factor);
   property_name = base_property_name + "/boost-speed";
   PropertyManager->Tie(property_name, &BoostSpeed);
+  property_name = base_property_name + "/cht-degF";
+  PropertyManager->Tie(property_name, this, &FGPiston::getCylinderHeadTemp_degF);
 
   // Set up and sanity-check the turbo/supercharging configuration based on the input values.
   if (TakeoffBoost > RatedBoost[0]) bTakeoffBoost = true;
@@ -642,7 +651,7 @@ void FGPiston::doAirFlow(void)
 // loss of volumentric efficiency due to difference between MAP and exhaust pressure
 // Eq 6-10 from The Internal Combustion Engine - Charles Taylor Vol 1
   double ve =((gamma-1)/gamma) +( CompressionRatio -(p_amb/MAP))/(gamma*( CompressionRatio - 1));
-
+// FGAtmosphere::GetDensity() * FGJSBBase::m3toft3 / FGJSBBase::kgtoslug;
   rho_air = p_amb / (R_air * T_amb);
   double swept_volume = (displacement_SI * (RPM/60)) / 2;
   double v_dot_air = swept_volume * volumetric_efficiency *ve;
@@ -766,7 +775,7 @@ void FGPiston::doEGT(void)
  * Calculate the cylinder head temperature.
  *
  * Inputs: T_amb, IAS, rho_air, m_dot_fuel, calorific_value_fuel,
- *   combustion_efficiency, RPM, MaxRPM, Displacement
+ *   combustion_efficiency, RPM, MaxRPM, Displacement, Cylinders
  *
  * Outputs: CylinderHeadTemp_degK
  */
@@ -779,17 +788,17 @@ void FGPiston::doCHT(void)
 
   double arbitary_area = Displacement/360.0;
   double CpCylinderHead = 800.0;
-  double MassCylinderHead = 8.0;
+  double MassCylinderHead = CylinderHeadMass * Cylinders;
 
   double temperature_difference = CylinderHeadTemp_degK - T_amb;
-  double v_apparent = IAS * 0.5144444;
+  double v_apparent = IAS * Cooling_Factor;
   double v_dot_cooling_air = arbitary_area * v_apparent;
   double m_dot_cooling_air = v_dot_cooling_air * rho_air;
   double dqdt_from_combustion =
     m_dot_fuel * calorific_value_fuel * combustion_efficiency * 0.33;
   double dqdt_forced = (h2 * m_dot_cooling_air * temperature_difference) +
     (h3 * RPM * temperature_difference / MaxRPM);
-  double dqdt_free = h1 * temperature_difference;
+  double dqdt_free = h1 * temperature_difference * arbitary_area;
   double dqdt_cylinder_head = dqdt_from_combustion + dqdt_forced + dqdt_free;
 
   double HeatCapacityCylinderHead = CpCylinderHead * MassCylinderHead;
@@ -921,6 +930,7 @@ void FGPiston::Debug(int from)
       cout << "      Bore: "                << Bore                     << endl;
       cout << "      Stroke: "              << Stroke                   << endl;
       cout << "      Cylinders: "           << Cylinders                << endl;
+      cout << "      Cylinders Head Mass: " <<CylinderHeadMass          << endl;
       cout << "      Compression Ratio: "   << CompressionRatio         << endl;
       cout << "      MaxHP: "               << MaxHP                    << endl;
       cout << "      Cycles: "              << Cycles                   << endl;

diff --git a/src/FDM/JSBSim/models/propulsion/FGPiston.h b/src/FDM/JSBSim/models/propulsion/FGPiston.h
index 13072afac2ef0883897f35aa79e9c9078de022f4..510c6e6f2c185a15a531221f5abfc645086256cf 100644 (file)
--- a/src/FDM/JSBSim/models/propulsion/FGPiston.h
+++ b/src/FDM/JSBSim/models/propulsion/FGPiston.h
@@ -46,7 +46,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_PISTON "$Id: FGPiston.h,v 1.24 2010/08/21 18:08:13 jberndt Exp $";
+#define ID_PISTON "$Id: FGPiston.h,v 1.25 2010/11/30 12:17:10 jberndt Exp $";
 #define FG_MAX_BOOST_SPEEDS 3
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -71,6 +71,7 @@ CLASS DOCUMENTATION
   <bore unit="{IN | M}"> {number} </bore>
   <stroke unit="{IN | M}"> {number} </stroke>
   <cylinders> {number} </cylinders>
+  <cylinder-head-mass unit="{KG | LBS}"> {number} </cylinder-head-mass>
   <compression-ratio> {number} </compression-ratio>
   <sparkfaildrop> {number} </sparkfaildrop>
   <maxhp unit="{HP | WATTS}"> {number} </maxhp>
@@ -101,6 +102,7 @@ CLASS DOCUMENTATION
   <takeoffboost unit="{INHG | PA | ATM}"> {number} </takeoffboost>
   <air-intake-impedance-factor> {number} </air-intake-impedance-factor>
   <ram-air-factor> {number} </ram-air-factor>
+  <cooling-factor> {number} </cooling-factor>
 </piston_engine>
 @endcode
 
@@ -160,8 +162,7 @@ CLASS DOCUMENTATION
       config file (and is above RATEDBOOST1), then the throttle position is
       interpreted as:
 
-    - 0 to 0.95 : idle manifold pressure to rated boost (where attainable)
-    - 0.96, 0.97, 0.98 : rated boost (where attainable).
+    - 0 to 0.98 : idle manifold pressure to rated boost (where attainable)
     - 0.99, 1.0 : takeoff boost (where attainable).
 
     A typical takeoff boost for an earlyish Merlin was about 12psi, compared
@@ -181,7 +182,7 @@ CLASS DOCUMENTATION
     @author Dave Luff (engine operational code)
     @author David Megginson (initial porting and additional code)
     @author Ron Jensen (additional engine code)
-    @version $Id: FGPiston.h,v 1.24 2010/08/21 18:08:13 jberndt Exp $
+    @version $Id: FGPiston.h,v 1.25 2010/11/30 12:17:10 jberndt Exp $
   */
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -200,21 +201,21 @@ public:
   std::string GetEngineValues(const std::string& delimiter);
 
   void Calculate(void);
-  double GetPowerAvailable(void) {return PowerAvailable;}
+  double GetPowerAvailable(void) const {return PowerAvailable;}
   double CalcFuelNeed(void);
 
   void ResetToIC(void);
   void SetMagnetos(int magnetos) {Magnetos = magnetos;}
 
-  double  GetEGT(void) { return EGT_degC; }
-  int     GetMagnetos(void) {return Magnetos;}
+  double  GetEGT(void) const { return EGT_degC; }
+  int     GetMagnetos(void) const {return Magnetos;}
 
-  double getExhaustGasTemp_degF(void) {return KelvinToFahrenheit(ExhaustGasTemp_degK);}
+  double getExhaustGasTemp_degF(void) const {return KelvinToFahrenheit(ExhaustGasTemp_degK);}
   double getManifoldPressure_inHg(void) const {return ManifoldPressure_inHg;}
-  double getCylinderHeadTemp_degF(void) {return KelvinToFahrenheit(CylinderHeadTemp_degK);}
+  double getCylinderHeadTemp_degF(void) const {return KelvinToFahrenheit(CylinderHeadTemp_degK);}
   double getOilPressure_psi(void) const {return OilPressure_psi;}
-  double getOilTemp_degF (void) {return KelvinToFahrenheit(OilTemp_degK);}
-  double getRPM(void) {return RPM;}
+  double getOilTemp_degF (void) const {return KelvinToFahrenheit(OilTemp_degK);}
+  double getRPM(void) const {return RPM;}
 
 protected:
 
@@ -275,6 +276,7 @@ private:
   double Bore;                     // inches
   double Stroke;                   // inches
   double Cylinders;                // number
+  double CylinderHeadMass;         // kilograms
   double CompressionRatio;         // number
   double Z_airbox; // number representing intake impediance before the throttle
   double Z_throttle; // number representing slope of throttle impediance
@@ -321,6 +323,7 @@ private:
   double T_amb;              // degrees Kelvin
   double RPM;                // revolutions per minute
   double IAS;                // knots
+  double Cooling_Factor;     // normal
   bool Magneto_Left;
   bool Magneto_Right;
   int Magnetos;