Fixes from Cameron Moore:

[flightgear.git] / src / FDM / JSBSim / FGPiston.cpp

diff --git a/src/FDM/JSBSim/FGPiston.cpp b/src/FDM/JSBSim/FGPiston.cpp
index d7f8d1c2bae3d6f4e6fe5e79e1f91e6ded946e7c..b8eb6a5efe40a08aa98e13dfaf85a54db880dcb2 100644 (file)
--- a/src/FDM/JSBSim/FGPiston.cpp
+++ b/src/FDM/JSBSim/FGPiston.cpp
@@ -78,7 +78,6 @@ FGPiston::FGPiston(FGFDMExec* exec, FGConfigFile* Eng_cfg) : FGEngine(exec),
     else if (token == "IDLERPM") *Eng_cfg >> IdleRPM;
     else if (token == "MAXTHROTTLE") *Eng_cfg >> MaxThrottle;
     else if (token == "MINTHROTTLE") *Eng_cfg >> MinThrottle;
-    else if (token == "SLFUELFLOWMAX") *Eng_cfg >> SLFuelFlowMax;
     else cerr << "Unhandled token in Engine config file: " << token << endl;
   }
 
@@ -137,7 +136,6 @@ FGPiston::~FGPiston()
 
 double FGPiston::Calculate(double PowerRequired)
 {
-  // FIXME: calculate from actual fuel flow
   ConsumeFuel();
 
   Throttle = FCS->GetThrottlePos(EngineNumber);
@@ -156,7 +154,7 @@ double FGPiston::Calculate(double PowerRequired)
     
   IAS = Auxiliary->GetVcalibratedKTS();
 
-  if (Mixture >= 0.5) {
+  if (Mixture >= 0.3) {
     doEngineStartup();
     doManifoldPressure();
     doAirFlow();
@@ -181,9 +179,6 @@ double FGPiston::Calculate(double PowerRequired)
 
 void FGPiston::doEngineStartup(void)
 {
-  // TODO: check magnetos, spark, starter, etc. and decide whether
-  // engine is running
-
   // Check parameters that may alter the operating state of the engine. 
   // (spark, fuel, starter motor etc)
   bool spark;
@@ -207,7 +202,7 @@ void FGPiston::doEngineStartup(void)
   if (Magnetos > 1)  Magneto_Right = true;
 
   // Assume we have fuel for now
-  fuel = true;
+  fuel = !Starved;
 
   // Check if we are turning the starter motor
   if (Cranking != Starter) {
@@ -299,6 +294,9 @@ void FGPiston::doManifoldPressure(void)
 /**
  * Calculate the air flow through the engine.
  *
+ * At this point, ManifoldPressure_inHg still represents the sea-level
+ * MP, not adjusted for altitude.
+ *
  * Inputs: p_amb, R_air, T_amb, ManifoldPressure_inHg, Displacement,
  *   RPM, volumetric_efficiency
  *
@@ -329,6 +327,10 @@ void FGPiston::doFuelFlow(void)
   double thi_sea_level = 1.3 * Mixture;
   equivalence_ratio = thi_sea_level * p_amb_sea_level / p_amb;
   m_dot_fuel = m_dot_air / 14.7 * equivalence_ratio;
+  FuelFlow_gph = m_dot_fuel
+    * 3600                     // seconds to hours
+    * 2.2046                   // kg to lb
+    / 6.6;                     // lb to gal_us of kerosene
 }
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -348,8 +350,8 @@ void FGPiston::doFuelFlow(void)
 
 void FGPiston::doEnginePower(void)
 {
-  double True_ManifoldPressure_inHg = ManifoldPressure_inHg * p_amb / p_amb_sea_level;
-  double ManXRPM = True_ManifoldPressure_inHg * RPM;
+  ManifoldPressure_inHg *= p_amb / p_amb_sea_level;
+  double ManXRPM = ManifoldPressure_inHg * RPM;
         // FIXME: this needs to be generalized
   Percentage_Power = (6e-9 * ManXRPM * ManXRPM) + (8e-4 * ManXRPM) - 1.0;
   double T_amb_degF = (T_amb * 1.8) - 459.67;
@@ -546,7 +548,6 @@ void FGPiston::Debug(int from)
       cout << "      IdleRPM: "             << IdleRPM                  << endl;
       cout << "      MaxThrottle: "         << MaxThrottle              << endl;
       cout << "      MinThrottle: "         << MinThrottle              << endl;
-      cout << "      SLFuelFlowMax: "       << SLFuelFlowMax            << endl;
 
       cout << endl;
       cout << "      Combustion Efficiency table:" << endl;
@@ -578,3 +579,8 @@ void FGPiston::Debug(int from)
   }
 }
 
+double
+FGPiston::CalcFuelNeed(void)
+{
+  return FuelFlow_gph / 3600 * State->Getdt() * Propulsion->GetRate();
+}