Sync. w. JSBSim CVS

src/FDM/JSBSim/FGFDMExec.cpp

@@ -514,56 +514,170 @@ bool FGFDMExec::LoadModel(string model, bool addModelToPath)
   document = LoadXMLDocument(aircraftCfgFileName); // "document" is a class member
   if (document) {
     ReadPrologue(document);
-    element = document->GetElement();
 
-    result = true;
+    // Process the fileheader element in the aircraft config file. This element is OPTIONAL.
-    while (element && result) {
+    element = document->FindElement("fileheader");
-      string element_name = element->GetName();
+    if (element) {
-      if (element_name == "fileheader" )           result = ReadFileHeader(element);
+      result = ReadFileHeader(element);
-      else if (element_name == "slave")            result = ReadSlave(element);
+      if (!result) {
-      else if (element_name == "metrics")          result = Aircraft->Load(element);
+        cerr << endl << "Aircraft fileheader element has problems in file " << aircraftCfgFileName << endl;
-      else if (element_name == "mass_balance")     result = MassBalance->Load(element);
+        return result;
-      else if (element_name == "ground_reactions") result = GroundReactions->Load(element);
+      }
-      else if (element_name == "external_reactions") result = ExternalReactions->Load(element);
+    }
-      else if (element_name == "buoyant_forces")   result = BuoyantForces->Load(element);
+
-      else if (element_name == "propulsion")       result = Propulsion->Load(element);
+    // Process the metrics element. This element is REQUIRED.
-      else if (element_name == "system")           result = FCS->Load(element,
+    element = document->FindElement("metrics");
-                                                            FGFCS::stSystem);
+    if (element) {
-      else if (element_name == "autopilot")        result = FCS->Load(element,
+      result = Aircraft->Load(element);
-                                                            FGFCS::stAutoPilot);
+      if (!result) {
-      else if (element_name == "flight_control")   result = FCS->Load(element,
+        cerr << endl << "Aircraft metrics element has problems in file " << aircraftCfgFileName << endl;
-                                                            FGFCS::stFCS);
+        return result;
-      else if (element_name == "aerodynamics")     result = Aerodynamics->Load(element);
+      }
-      else if (element_name == "input")            result = Input->Load(element);
+    } else {
-      else if (element_name == "output")           {
+      cerr << endl << "No metrics element was found in the aircraft config file." << endl;
+      return false;
+    }
+
+    // Process the mass_balance element. This element is REQUIRED.
+    element = document->FindElement("mass_balance");
+    if (element) {
+      result = MassBalance->Load(element);
+      if (!result) {
+        cerr << endl << "Aircraft mass_balance element has problems in file " << aircraftCfgFileName << endl;
+        return result;
+      }
+    } else {
+      cerr << endl << "No mass_balance element was found in the aircraft config file." << endl;
+      return false;
+    }
+
+    // Process the ground_reactions element. This element is REQUIRED.
+    element = document->FindElement("ground_reactions");
+    if (element) {
+      result = GroundReactions->Load(element);
+      if (!result) {
+        cerr << endl << "Aircraft ground_reactions element has problems in file " << aircraftCfgFileName << endl;
+        return result;
+      }
+    } else {
+      cerr << endl << "No ground_reactions element was found in the aircraft config file." << endl;
+      return false;
+    }
+
+    // Process the external_reactions element. This element is OPTIONAL.
+    element = document->FindElement("external_reactions");
+    if (element) {
+      result = ExternalReactions->Load(element);
+      if (!result) {
+        cerr << endl << "Aircraft external_reactions element has problems in file " << aircraftCfgFileName << endl;
+        return result;
+      }
+    }
+
+    // Process the buoyant_forces element. This element is OPTIONAL.
+    element = document->FindElement("buoyant_forces");
+    if (element) {
+      result = BuoyantForces->Load(element);
+      if (!result) {
+        cerr << endl << "Aircraft buoyant_forces element has problems in file " << aircraftCfgFileName << endl;
+        return result;
+      }
+    }
+
+    // Process the propulsion element. This element is OPTIONAL.
+    element = document->FindElement("propulsion");
+    if (element) {
+      result = Propulsion->Load(element);
+      if (!result) {
+        cerr << endl << "Aircraft propulsion element has problems in file " << aircraftCfgFileName << endl;
+        return result;
+      }
+    }
+
+    // Process the system element[s]. This element is OPTIONAL, and there may be more than one.
+    element = document->FindElement("system");
+    while (element) {
+      result = FCS->Load(element, FGFCS::stSystem);
+      if (!result) {
+        cerr << endl << "Aircraft system element has problems in file " << aircraftCfgFileName << endl;
+        return result;
+      }
+      element = document->FindNextElement("system");
+    }
+
+    // Process the autopilot element. This element is OPTIONAL.
+    element = document->FindElement("autopilot");
+    if (element) {
+      result = FCS->Load(element, FGFCS::stAutoPilot);
+      if (!result) {
+        cerr << endl << "Aircraft autopilot element has problems in file " << aircraftCfgFileName << endl;
+        return result;
+      }
+    }
+
+    // Process the flight_control element. This element is OPTIONAL.
+    element = document->FindElement("flight_control");
+    if (element) {
+      result = FCS->Load(element, FGFCS::stFCS);
+      if (!result) {
+        cerr << endl << "Aircraft flight_control element has problems in file " << aircraftCfgFileName << endl;
+        return result;
+      }
+    }
+
+    // Process the aerodynamics element. This element is OPTIONAL, but almost always expected.
+    element = document->FindElement("aerodynamics");
+    if (element) {
+      result = Aerodynamics->Load(element);
+      if (!result) {
+        cerr << endl << "Aircraft aerodynamics element has problems in file " << aircraftCfgFileName << endl;
+        return result;
+      }
+    } else {
+      cerr << endl << "No expected aerodynamics element was found in the aircraft config file." << endl;
+    }
+
+    // Process the input element. This element is OPTIONAL.
+    element = document->FindElement("input");
+    if (element) {
+      result = Input->Load(element);
+      if (!result) {
+        cerr << endl << "Aircraft input element has problems in file " << aircraftCfgFileName << endl;
+        return result;
+      }
+    }
+
+    // Process the output element[s]. This element is OPTIONAL, and there may be more than one.
+    element = document->FindElement("output");
+    while (element) {
       FGOutput* Output = new FGOutput(this);
       Output->InitModel();
       Schedule(Output, 1);
       result = Output->Load(element);
       Outputs.push_back(Output);
+      if (!result) {
+        cerr << endl << "Aircraft output element has problems in file " << aircraftCfgFileName << endl;
+        return result;
+      }
+      element = document->FindNextElement("output");
+    }
+
+    // Lastly, process the slave element. This element is OPTIONAL - and NOT YET SUPPORTED.
+    element = document->FindElement("slave");
+    if (element) {
+      result = ReadSlave(element);
+      if (!result) {
+        cerr << endl << "Aircraft slave element has problems in file " << aircraftCfgFileName << endl;
+        return result;
       }
-      else {
-        cerr << "Found unexpected subsystem: " << element_name << ", exiting." << endl;
-        result = false;
-        break;
-      }
-      element = document->GetNextElement();
-    }
-  } else {
-    cerr << fgred
-         << "  JSBSim failed to load aircraft model."
-         << fgdef << endl;
-    return false;
     }
 
-  if (result) {
     modelLoaded = true;
-    Debug(3);
+
   } else {
     cerr << fgred
-         << "  JSBSim failed to load properly."
+         << "  JSBSim failed to open the configuration file: " << aircraftCfgFileName
          << fgdef << endl;
-    return false;
   }
 
   struct PropertyCatalogStructure masterPCS;

src/FDM/JSBSim/JSBSim.cxx

@@ -150,9 +150,6 @@ FGJSBsim::FGJSBsim( double dt )
     // file on each FlightGear reset.
     fgGetNode("/fdm/jsbsim/simulation/write-state-file")->untie();
     fgGetNode("/fdm/jsbsim/simulation")->removeChild("write-state-file", false);
-    // Prevent nuking of the state on JSBSim recreation after FlightGear reset.
-    fgGetNode("/fdm/jsbsim/simulation/reset")->untie();
-    fgGetNode("/fdm/jsbsim/simulation")->removeChild("reset", false);
     // end ugly hack
 
     // Register ground callback.
@@ -328,9 +325,9 @@ void FGJSBsim::init()
       Atmosphere->UseInternal();
     }
 
-    fgic->SetVNorthFpsIC( wind_from_north->getDoubleValue() );
+    fgic->SetVNorthFpsIC( -wind_from_north->getDoubleValue() );
-    fgic->SetVEastFpsIC( wind_from_east->getDoubleValue() );
+    fgic->SetVEastFpsIC( -wind_from_east->getDoubleValue() );
-    fgic->SetVDownFpsIC( wind_from_down->getDoubleValue() );
+    fgic->SetVDownFpsIC( -wind_from_down->getDoubleValue() );
 
     //Atmosphere->SetExTemperature(get_Static_temperature());
     //Atmosphere->SetExPressure(get_Static_pressure());
@@ -625,9 +622,9 @@ bool FGJSBsim::copy_to_JSBsim()
     tmp = turbulence_rate->getDoubleValue();
     //Atmosphere->SetTurbRate(tmp);
 
-    Atmosphere->SetWindNED( wind_from_north->getDoubleValue(),
+    Atmosphere->SetWindNED( -wind_from_north->getDoubleValue(),
-                            wind_from_east->getDoubleValue(),
+                            -wind_from_east->getDoubleValue(),
-                            wind_from_down->getDoubleValue() );
+                            -wind_from_down->getDoubleValue() );
 //    SG_LOG(SG_FLIGHT,SG_INFO, "Wind NED: "
 //                  << get_V_north_airmass() << ", "
 //                  << get_V_east_airmass()  << ", "
@@ -1100,6 +1097,7 @@ void FGJSBsim::init_gear(void )
       node->setDoubleValue("yoffset-in", gear->GetBodyLocation()(2));
       node->setDoubleValue("zoffset-in", gear->GetBodyLocation()(3));
       node->setBoolValue("wow", gear->GetWOW());
+      node->setDoubleValue("rollspeed-ms", gear->GetWheelRollVel()*0.3043);
       node->setBoolValue("has-brake", gear->GetBrakeGroup() > 0);
       node->setDoubleValue("position-norm", gear->GetGearUnitPos());
       node->setDoubleValue("tire-pressure-norm", gear->GetTirePressure());
@@ -1118,6 +1116,7 @@ void FGJSBsim::update_gear(void)
       FGLGear *gear = gr->GetGearUnit(i);
       SGPropertyNode * node = fgGetNode("gear/gear", i, true);
       node->getChild("wow", 0, true)->setBoolValue( gear->GetWOW());
+      node->getChild("rollspeed-ms", 0, true)->setDoubleValue(gear->GetWheelRollVel()*0.3043);
       node->getChild("position-norm", 0, true)->setDoubleValue(gear->GetGearUnitPos());
       gear->SetTirePressure(node->getDoubleValue("tire-pressure-norm"));
       node->setDoubleValue("compression-norm", gear->GetCompLen());

src/FDM/JSBSim/initialization/FGInitialCondition.cpp

@@ -69,7 +69,9 @@ FGInitialCondition::FGInitialCondition(FGFDMExec *FDMExec) : fdmex(FDMExec)
     fdmex->GetPropagate()->Seth(altitude);
     fdmex->GetAtmosphere()->Run();
     PropertyManager=fdmex->GetPropertyManager();
+    Constructing = true;
     bind();
+    Constructing = false;
   } else {
     cout << "FGInitialCondition: This class requires a pointer to a valid FGFDMExec object" << endl;
   }
@@ -156,6 +158,8 @@ void FGInitialCondition::InitializeIC(void)
 
 void FGInitialCondition::WriteStateFile(int num)
 {
+  if (Constructing) return;
+
   string filename = fdmex->GetFullAircraftPath();
 
   if (filename.empty())

src/FDM/JSBSim/initialization/FGInitialCondition.h

@@ -644,6 +644,7 @@ private:
   FGFDMExec *fdmex;
   FGPropertyManager *PropertyManager;
 
+  bool Constructing;
   bool getAlpha(void);
   bool getTheta(void);
   bool getMachFromVcas(double *Mach,double vcas);

src/FDM/JSBSim/models/FGLGear.cpp

@@ -340,6 +340,9 @@ FGColumnVector3& FGLGear::Force(void)
       WOW = false;
       compressLength = 0.0;
 
+      // No wheel conditons
+      RollingWhlVel = SideWhlVel = WheelSlip = 0.0;
+
       // Return to neutral position between 1.0 and 0.8 gear pos.
       SteerAngle *= max(GetGearUnitPos()-0.8, 0.0)/0.2;
 

src/FDM/JSBSim/models/propulsion/FGPiston.cpp

@@ -71,8 +71,9 @@ FGPiston::FGPiston(FGFDMExec* exec, Element* el, int engine_number)
   dt = State->Getdt();
 
   // These items are read from the configuration file
+  // Defaults are from a Lycoming O-360, more or less
 
-  Cycles = 2;
+  Cycles = 4;
   IdleRPM = 600;
   MaxRPM = 2800;
   Displacement = 360;
@@ -80,10 +81,12 @@ FGPiston::FGPiston(FGFDMExec* exec, Element* el, int engine_number)
   MaxHP = 200;
   MinManifoldPressure_inHg = 6.5;
   MaxManifoldPressure_inHg = 28.5;
-  BSFC = -1;
+  ISFC = -1;
-
+  volumetric_efficiency = -0.1;
-  // Initialisation
+  Bore = 5.125;
-  volumetric_efficiency = 0.8;  // Actually f(speed, load) but this will get us running
+  Stroke = 4.375;
+  Cylinders = 4;
+  CompressionRatio = 8.5;
 
   // These are internal program variables
 
@@ -173,9 +176,17 @@ FGPiston::FGPiston(FGFDMExec* exec, Element* el, int engine_number)
   if (el->FindElement("minthrottle"))
     MinThrottle = el->FindElementValueAsNumber("minthrottle");
   if (el->FindElement("bsfc"))
-    BSFC = el->FindElementValueAsNumberConvertTo("bsfc", "LBS/HP*HR");
+    ISFC = el->FindElementValueAsNumberConvertTo("bsfc", "LBS/HP*HR");
   if (el->FindElement("volumetric-efficiency"))
     volumetric_efficiency = el->FindElementValueAsNumber("volumetric-efficiency");
+  if (el->FindElement("compression-ratio"))
+    CompressionRatio = el->FindElementValueAsNumber("compression-ratio");
+  if (el->FindElement("bore"))
+    Bore = el->FindElementValueAsNumberConvertTo("bore","IN");
+  if (el->FindElement("stroke"))
+    Stroke = el->FindElementValueAsNumberConvertTo("stroke","IN");
+  if (el->FindElement("stroke"))
+    Cylinders = el->FindElementValueAsNumber("cylinders");
   if (el->FindElement("numboostspeeds")) { // Turbo- and super-charging parameters
     BoostSpeeds = (int)el->FindElementValueAsNumber("numboostspeeds");
     if (el->FindElement("boostoverride"))
@@ -208,30 +219,42 @@ FGPiston::FGPiston(FGFDMExec* exec, Element* el, int engine_number)
       RatedAltitude[2] = el->FindElementValueAsNumberConvertTo("ratedaltitude3", "FT");
   }
 
-  MaxManifoldPressure_Percent = MaxManifoldPressure_inHg / 29.92;
+  StarterHP = sqrt(MaxHP) * 0.4;
-  // Create a BSFC to match the engine if not provided
+  displacement_SI = Displacement * in3tom3;
-  if (BSFC < 0) {
+
-      BSFC = ( Displacement * MaxRPM * volumetric_efficiency ) / (9411 * MaxHP);
+  // Create IFSC and VE to match the engine if not provided
-      BSFC *= (MaxManifoldPressure_Percent * MaxManifoldPressure_Percent * MaxManifoldPressure_Percent);
+  int calculated_ve=0;
+  if (volumetric_efficiency < 0) {
+      volumetric_efficiency = MaxManifoldPressure_inHg / 29.92;
+      calculated_ve=1;
+  }
+  if (ISFC < 0) {
+      double pmep = MaxManifoldPressure_inHg > 29.92 ? 0 : 29.92 - MaxManifoldPressure_inHg;
+      pmep *= inhgtopa;
+      double fmep = (18400 * (2*(Stroke/12)*(MaxRPM/60)) * fttom + 46500)/2;
+      double hp_loss = ((pmep + fmep) * displacement_SI * MaxRPM)/(Cycles*22371);
+      ISFC = ( Displacement * MaxRPM * volumetric_efficiency ) / (9411 * (MaxHP+hp_loss));
+// cout <<"FMEP: "<< fmep <<" PMEP: "<< pmep << " hp_loss: " <<hp_loss <<endl;
   }
   if ( MaxManifoldPressure_inHg > 29.9 ) {   // Don't allow boosting with a bogus number
       MaxManifoldPressure_inHg = 29.9;
-      MaxManifoldPressure_Percent = MaxManifoldPressure_inHg / 29.92;
+      if (calculated_ve) volumetric_efficiency = 1.0;
   }
+  minMAP = MinManifoldPressure_inHg * inhgtopa;  // inHg to Pa
+  maxMAP = MaxManifoldPressure_inHg * inhgtopa;
 
   string property_name, base_property_name;
   base_property_name = CreateIndexedPropertyName("propulsion/engine", EngineNumber);
   property_name = base_property_name + "/power-hp";
   PropertyManager->Tie(property_name, &HP);
   property_name = base_property_name + "/bsfc-lbs_hphr";
-  PropertyManager->Tie(property_name, &BSFC);
+  PropertyManager->Tie(property_name, &ISFC);
   property_name = base_property_name + "/volumetric-efficiency";
   PropertyManager->Tie(property_name, &volumetric_efficiency);
+  property_name = base_property_name + "/map-pa";
+  PropertyManager->Tie(property_name, &MAP);
   property_name = base_property_name + "/map-inhg";
   PropertyManager->Tie(property_name, &ManifoldPressure_inHg);
-  minMAP = MinManifoldPressure_inHg * inhgtopa;  // inHg to Pa
-  maxMAP = MaxManifoldPressure_inHg * inhgtopa;
-  StarterHP = sqrt(MaxHP) * 0.4;
 
   // Set up and sanity-check the turbo/supercharging configuration based on the input values.
   if (TakeoffBoost > RatedBoost[0]) bTakeoffBoost = true;
@@ -279,9 +302,6 @@ FGPiston::FGPiston(FGFDMExec* exec, Element* el, int engine_number)
     BoostSpeed = 0;
   }
   bBoostOverride = (BoostOverride == 1 ? true : false);
-  if (MinThrottle < 0.12) MinThrottle = 0.12;  //MinThrottle is limited to 0.12 to prevent the
-                                               // throttle area equation from going negative
-                                               // 0.12 is 1% of maximum area
   Debug(0); // Call Debug() routine from constructor if needed
 }
 
@@ -319,7 +339,7 @@ double FGPiston::Calculate(void)
   if (FuelFlow_gph > 0.0) ConsumeFuel();
 
   Throttle = FCS->GetThrottlePos(EngineNumber);
-  // calculate the throttle plate angle.  1 unit is pi/2 radians.
+  // calculate the throttle plate angle.  1 unit is approx pi/2 radians.
   ThrottleAngle = MinThrottle+((MaxThrottle-MinThrottle)*Throttle );
   Mixture = FCS->GetMixturePos(EngineNumber);
 
@@ -328,10 +348,10 @@ double FGPiston::Calculate(void)
   //
 
   p_amb = Atmosphere->GetPressure() * psftopa;
-  p_amb_sea_level = Atmosphere->GetPressureSL() * psftopa;
   T_amb = RankineToKelvin(Atmosphere->GetTemperature());
 
   RPM = Thruster->GetRPM() * Thruster->GetGearRatio();
+  MeanPistonSpeed_fps =  ( RPM * Stroke) / (360); // AKA 2 * (RPM/60) * ( Stroke / 12) or 2NS
 
   IAS = Auxiliary->GetVcalibratedKTS();
 
@@ -349,7 +369,7 @@ double FGPiston::Calculate(void)
 //    Running = false;
 
   doEnginePower();
-  if (HP < 0.1250) Running = false;
+  if (IndicatedHorsePower < 0.1250) Running = false;
 
   doEGT();
   doCHT();
@@ -489,20 +509,33 @@ void FGPiston::doBoostControl(void)
  * from the throttle position, turbo/supercharger boost control
  * system, engine speed and local ambient air density.
  *
- * Inputs: p_amb, Throttle, MaxManifoldPressure_Percent, ThrottleAngle
+ * Inputs: p_amb, Throttle, ThrottleAngle,
- *         RPM, MaxRPM
+ *         MeanPistonSpeed_fps, dt
  *
  * Outputs: MAP, ManifoldPressure_inHg
  */
 
 void FGPiston::doMAP(void)
 {
- // estimate throttle plate area.  This maps 0.2 -> 0.1 for historical performance reasons
+ // estimate throttle plate area.
-    double throttle_area = ThrottleAngle * 1.125 - 0.125;
+  double throttle_area = ThrottleAngle*ThrottleAngle;
-    map_coefficient = pow ((throttle_area * MaxManifoldPressure_Percent),RPM/MaxRPM);
+ // Internal Combustion Engine in Theory and Practice, Volume 2.  Charles Fayette Taylor.  Revised Edition, 1985 fig 6-13
-    MAP = p_amb * map_coefficient;
+  double map_coefficient = 1-((MeanPistonSpeed_fps*MeanPistonSpeed_fps)/(24978*throttle_area));
 
-    if(Boosted) {
+  if ( map_coefficient < 0.1 ) map_coefficient = 0.1;
+
+  // map_coefficient = pow ((throttle_area * MaxManifoldPressure_Percent),RPM/MaxRPM);
+  // Add a one second lag to manifold pressure changes
+  double dMAP = (MAP - p_amb * map_coefficient) * dt;
+  MAP -=dMAP;
+
+  // Find the mean effective pressure required to achieve this manifold pressure
+  // Doing this before boost so boost doesn't add horsepower to the engine.
+  // A better method would be deterimining the HP consumed by the supercharger
+
+  PMEP = MAP - p_amb; // Fixme: p_amb should be exhaust manifold pressure
+
+  if (Boosted) {
     // If takeoff boost is fitted, we currently assume the following throttle map:
     // (In throttle % - actual input is 0 -> 1)
     // 99 / 100 - Takeoff boost
@@ -510,19 +543,15 @@ void FGPiston::doMAP(void)
     // 0 - 95 - Idle to Rated boost (MinManifoldPressure to MaxManifoldPressure)
     // In real life, most planes would be fitted with a mechanical 'gate' between
     // the rated boost and takeoff boost positions.
-      double T = Throttle; // processed throttle value.
+
     bool bTakeoffPos = false;
-      if(bTakeoffBoost) {
+    if (bTakeoffBoost) {
-        if(Throttle > 0.98) {
+      if (Throttle > 0.98) {
-          //cout << "Takeoff Boost!!!!\n";
         bTakeoffPos = true;
       } else if(Throttle <= 0.95) {
         bTakeoffPos = false;
-          T *= 1.0 / 0.95;
       } else {
         bTakeoffPos = false;
-          //cout << "Rated Boost!!\n";
-          T = 1.0;
       }
     }
     // Boost the manifold pressure.
@@ -530,14 +559,10 @@ void FGPiston::doMAP(void)
     if (boost_factor < 1.0) boost_factor = 1.0;  // boost will never reduce the MAP
     MAP *= boost_factor;
     // Now clip the manifold pressure to BCV or Wastegate setting.
-      if(bTakeoffPos) {
+    if (bTakeoffPos) {
-        if(MAP > TakeoffMAP[BoostSpeed]) {
+      if (MAP > TakeoffMAP[BoostSpeed]) MAP = TakeoffMAP[BoostSpeed];
-          MAP = TakeoffMAP[BoostSpeed];
-        }
     } else {
-        if(MAP > RatedMAP[BoostSpeed]) {
+      if (MAP > RatedMAP[BoostSpeed]) MAP = RatedMAP[BoostSpeed];
-          MAP = RatedMAP[BoostSpeed];
-        }
     }
   }
 
@@ -561,20 +586,24 @@ void FGPiston::doMAP(void)
 
 void FGPiston::doAirFlow(void)
 {
+  double gamma = 1.4; // specific heat constants
+// loss of volumentric efficiency due to difference between MAP and exhaust pressure
+  double ve =((gamma-1)/gamma)+( CompressionRatio -(p_amb/MAP))/(gamma*( CompressionRatio - 1));
+
   rho_air = p_amb / (R_air * T_amb);
-  double displacement_SI = Displacement * in3tom3;
   double swept_volume = (displacement_SI * (RPM/60)) / 2;
-  double v_dot_air = swept_volume * volumetric_efficiency * map_coefficient;
+  double v_dot_air = swept_volume * volumetric_efficiency *ve;
 
   double rho_air_manifold = MAP / (R_air * T_amb);
   m_dot_air = v_dot_air * rho_air_manifold;
+
 }
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 /**
  * Calculate the fuel flow into the engine.
  *
- * Inputs: Mixture, thi_sea_level, p_amb_sea_level, p_amb, m_dot_air
+ * Inputs: Mixture, thi_sea_level, p_amb, m_dot_air
  *
  * Outputs: equivalence_ratio, m_dot_fuel
  */
@@ -601,49 +630,53 @@ void FGPiston::doFuelFlow(void)
  * 200HP.
  *
  * Inputs: ManifoldPressure_inHg, p_amb, RPM, T_amb,
- *   Mixture_Efficiency_Correlation, Cycles, MaxHP
+ *   Mixture_Efficiency_Correlation, Cycles, MaxHP, PMEP,
  *
- * Outputs: Percentage_Power, HP
+ * Outputs: PctPower, HP
  */
 
 void FGPiston::doEnginePower(void)
 {
+  IndicatedHorsePower = 0;
+  FMEP = 0;
   if (Running) {
     // FIXME: this needs to be generalized
-    double ME, friction, percent_RPM, power;  // Convienience term for use in the calculations
+    double ME, percent_RPM, power;  // Convienience term for use in the calculations
     ME = Mixture_Efficiency_Correlation->GetValue(m_dot_fuel/m_dot_air);
 
     percent_RPM = RPM/MaxRPM;
-    friction = 1 - (percent_RPM * percent_RPM * percent_RPM * percent_RPM/10);
+// Guestimate engine friction as a percentage of rated HP + a percentage of rpm + a percentage of Indicted HP
-    if (friction < 0 ) friction = 0;
+//    friction = 1 - (percent_RPM * percent_RPM * percent_RPM/10);
-    power = friction;
+    FMEP = (-18400 * MeanPistonSpeed_fps * fttom - 46500);
+
+    power = 1;
 
     if ( Magnetos != 3 ) power *= SparkFailDrop;
 
 
-    HP = (FuelFlow_gph * 6.0 / BSFC )* ME * map_coefficient * power;
+    IndicatedHorsePower = (FuelFlow_pph / ISFC )* ME * power;
 
   } else {
-
     // Power output when the engine is not running
     if (Cranking) {
       if (RPM < 10) {
-        HP = StarterHP;
+        IndicatedHorsePower = StarterHP;
       } else if (RPM < IdleRPM*0.8) {
-        HP = StarterHP + ((IdleRPM*0.8 - RPM) / 8.0);
+        IndicatedHorsePower = StarterHP + ((IdleRPM*0.8 - RPM) / 8.0);
         // This is a guess - would be nice to find a proper starter moter torque curve
       } else {
-        HP = StarterHP;
+        IndicatedHorsePower = StarterHP;
-      }
-    } else {
-      // Quick hack until we port the FMEP stuff
-      if (RPM > 0.0)
-        HP = -1.5;
-      else
-        HP = 0.0;
       }
     }
-  Percentage_Power = HP / MaxHP ;
+  }
+
+  // Constant is (1/2) * 60 * 745.7
+  // (1/2) convert cycles, 60 minutes to seconds, 745.7 watts to hp.
+  double pumping_hp = ((PMEP + FMEP) * displacement_SI * RPM)/(Cycles*22371);
+
+  HP = IndicatedHorsePower + pumping_hp - 1.5; //FIXME 1.5 static friction should depend on oil temp and configuration
+//  cout << "pumping_hp " <<pumping_hp << FMEP << PMEP <<endl;
+  PctPower = HP / MaxHP ;
 //  cout << "Power = " << HP << "  RPM = " << RPM << "  Running = " << Running << "  Cranking = " << Cranking << endl;
 }
 
@@ -652,7 +685,7 @@ void FGPiston::doEnginePower(void)
  * Calculate the exhaust gas temperature.
  *
  * Inputs: equivalence_ratio, m_dot_fuel, calorific_value_fuel,
- *   Cp_air, m_dot_air, Cp_fuel, m_dot_fuel, T_amb, Percentage_Power
+ *   Cp_air, m_dot_air, Cp_fuel, m_dot_fuel, T_amb, PctPower
  *
  * Outputs: combustion_efficiency, ExhaustGasTemp_degK
  */
@@ -671,7 +704,7 @@ void FGPiston::doEGT(void)
     heat_capacity_exhaust = (Cp_air * m_dot_air) + (Cp_fuel * m_dot_fuel);
     delta_T_exhaust = enthalpy_exhaust / heat_capacity_exhaust;
     ExhaustGasTemp_degK = T_amb + delta_T_exhaust;
-    ExhaustGasTemp_degK *= 0.444 + ((0.544 - 0.444) * Percentage_Power);
+    ExhaustGasTemp_degK *= 0.444 + ((0.544 - 0.444) * PctPower);
   } else {  // Drop towards ambient - guess an appropriate time constant for now
     combustion_efficiency = 0;
     dEGTdt = (RankineToKelvin(Atmosphere->GetTemperature()) - ExhaustGasTemp_degK) / 100.0;
@@ -837,12 +870,17 @@ void FGPiston::Debug(int from)
       cout << "      MinMaP (Pa):         " << minMAP << endl;
       cout << "      MaxMaP (Pa):         " << maxMAP << endl;
       cout << "      Displacement: "        << Displacement             << endl;
+      cout << "      Bore: "                << Bore                     << endl;
+      cout << "      Stroke: "              << Stroke                   << endl;
+      cout << "      Cylinders: "           << Cylinders                << endl;
+      cout << "      Compression Ratio: "   << CompressionRatio         << endl;
       cout << "      MaxHP: "               << MaxHP                    << endl;
       cout << "      Cycles: "              << Cycles                   << endl;
       cout << "      IdleRPM: "             << IdleRPM                  << endl;
       cout << "      MaxThrottle: "         << MaxThrottle              << endl;
       cout << "      MinThrottle: "         << MinThrottle              << endl;
-      cout << "      BSFC: "                << BSFC                     << endl;
+      cout << "      ISFC: "                << ISFC                     << endl;
+      cout << "      Volumentric Efficiency: " << volumetric_efficiency    << endl;
 
       cout << endl;
       cout << "      Combustion Efficiency table:" << endl;

src/FDM/JSBSim/models/propulsion/FGPiston.h

@@ -67,8 +67,12 @@ CLASS DOCUMENTATION
 @code
 <piston_engine name="{string}">
   <minmp unit="{INHG | PA | ATM}"> {number} </minmp> <!-- Depricated -->
-  <maxmp unit="{INHG | PA | ATM}"> {number} </maxmp> <!-- Depricated -->
+  <maxmp unit="{INHG | PA | ATM}"> {number} </maxmp>
   <displacement unit="{IN3 | LTR | CC}"> {number} </displacement>
+  <bore unit="{IN | M}"> {number} </bore>
+  <stroke unit="{IN | M}"> {number} </stroke>
+  <cylinders> {number} </cylinders>
+  <compression-ratio> {number} </compression-ratio>
   <sparkfaildrop> {number} </sparkfaildrop>
   <maxhp unit="{HP | WATTS}"> {number} </maxhp>
   <cycles> {number} </cycles>
@@ -76,9 +80,9 @@ CLASS DOCUMENTATION
   <maxrpm> {number} </maxrpm>
   <maxthrottle> {number} </maxthrottle>
   <minthrottle> {number} </minthrottle>
-  <numboostspeeds> {number} </numboostspeeds>
   <bsfc unit="{LBS/HP*HR | "KG/KW*HR"}"> {number} </bsft>
   <volumetric_efficiency> {number} </volumetric_efficiency>
+  <numboostspeeds> {number} </numboostspeeds>
   <boostoverride> {0 | 1} </boostoverride>
   <ratedboost1 unit="{INHG | PA | ATM}"> {number} </ratedboost1>
   <ratedpower1 unit="{HP | WATTS}"> {number} </ratedpower1>
@@ -210,7 +214,9 @@ protected:
 private:
   int crank_counter;
 
-  double BrakeHorsePower;
+  double IndicatedHorsePower;
+  double PMEP;
+  double FMEP;
   double SpeedSlope;
   double SpeedIntercept;
   double AltitudeSlope;
@@ -243,7 +249,6 @@ private:
   const double Cp_fuel;     // J/KgK
 
   FGTable *Lookup_Combustion_Efficiency;
-  FGTable *Power_Mixture_Correlation;
   FGTable *Mixture_Efficiency_Correlation;
 
   //
@@ -253,11 +258,17 @@ private:
   double MaxManifoldPressure_inHg; // Inches Hg
   double MaxManifoldPressure_Percent; // MaxManifoldPressure / 29.92
   double Displacement;             // cubic inches
+  double displacement_SI;          // cubic meters
   double MaxHP;                    // horsepower
   double SparkFailDrop;            // drop of power due to spark failure
   double Cycles;                   // cycles/power stroke
   double IdleRPM;                  // revolutions per minute
   double MaxRPM;                   // revolutions per minute
+  double Bore;                     // inches
+  double Stroke;                   // inches
+  double Cylinders;                // number
+  double CompressionRatio;        // number
+
   double StarterHP;                // initial horsepower of starter motor
   int BoostSpeeds;	// Number of super/turbocharger boost speeds - zero implies no turbo/supercharging.
   int BoostSpeed;	// The current boost-speed (zero-based).
@@ -284,13 +295,12 @@ private:
   double minMAP;  // Pa
   double maxMAP;  // Pa
   double MAP;     // Pa
-  double BSFC;    // brake specific fuel consumption [lbs/horsepower*hour
+  double ISFC;    // Indicated specific fuel consumption [lbs/horsepower*hour
 
   //
   // Inputs (in addition to those in FGEngine).
   //
   double p_amb;              // Pascals
-  double p_amb_sea_level;    // Pascals
   double T_amb;              // degrees Kelvin
   double RPM;                // revolutions per minute
   double IAS;                // knots
@@ -298,7 +308,6 @@ private:
   bool Magneto_Right;
   int Magnetos;
 
-
   //
   // Outputs (in addition to those in FGEngine).
   //
@@ -308,7 +317,6 @@ private:
   double m_dot_air;
   double equivalence_ratio;
   double m_dot_fuel;
-  double Percentage_Power;
   double HP;
   double combustion_efficiency;
   double ExhaustGasTemp_degK;
@@ -317,6 +325,7 @@ private:
   double CylinderHeadTemp_degK;
   double OilPressure_psi;
   double OilTemp_degK;
+  double MeanPistonSpeed_fps;
 
   void Debug(int from);
 };

src/FDM/JSBSim/models/propulsion/FGTank.cpp

@@ -37,6 +37,7 @@ INCLUDES
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
 #include "FGTank.h"
+#include <models/FGAuxiliary.h>
 
 using std::cerr;
 using std::endl;
@@ -52,7 +53,7 @@ CLASS IMPLEMENTATION
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
 FGTank::FGTank(FGFDMExec* exec, Element* el, int tank_number)
-                  : TankNumber(tank_number)
+                  : TankNumber(tank_number), Exec(exec)
 {
   string token;
   Element* element;
@@ -60,9 +61,8 @@ FGTank::FGTank(FGFDMExec* exec, Element* el, int tank_number)
   Area = 1.0;
   Temperature = -9999.0;
   Ixx = Iyy = Izz = 0.0;
-  Auxiliary = exec->GetAuxiliary();
   Radius = Capacity = Contents = Standpipe = Length = InnerRadius = 0.0;
-  PropertyManager = exec->GetPropertyManager();
+  PropertyManager = Exec->GetPropertyManager();
   vXYZ.InitMatrix();
   vXYZ_drain.InitMatrix();
 
@@ -245,7 +245,7 @@ double FGTank::Calculate(double dt)
   if (Temperature == -9999.0) return 0.0;
   double HeatCapacity = 900.0;        // Joules/lbm/C
   double TempFlowFactor = 1.115;      // Watts/sqft/C
-  double TAT = Auxiliary->GetTAT_C();
+  double TAT = Exec->GetAuxiliary()->GetTAT_C();
   double Tdiff = TAT - Temperature;
   double dTemp = 0.0;                 // Temp change due to one surface
   if (fabs(Tdiff) > 0.1) {

src/FDM/JSBSim/models/propulsion/FGTank.h

@@ -44,10 +44,10 @@ SENTRY
 INCLUDES
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
+#include "FGFDMExec.h"
 #include <FGJSBBase.h>
 #include <input_output/FGXMLElement.h>
 #include <math/FGColumnVector3.h>
-#include <models/FGAuxiliary.h>
 #include <string>
 
 using std::string;
@@ -281,7 +281,7 @@ private:
   double Temperature, InitialTemperature;
   double Standpipe, InitialStandpipe;
   bool  Selected;
-  FGAuxiliary* Auxiliary;
+  FGFDMExec* Exec;
   FGPropertyManager* PropertyManager;
   void CalculateInertias(void);
   void Debug(int from);