From: Erik Hofman <erik@ehofman.com>
Date: Fri, 17 Jun 2011 07:26:52 +0000 (+0200)
Subject: sync with JSBSim CVS
X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=ec454158fee605314172422bf0934263b5e1fe42;p=flightgear.git

sync with JSBSim CVS
---

diff --git a/src/FDM/JSBSim/FGFDMExec.cpp b/src/FDM/JSBSim/FGFDMExec.cpp
index a3b08a49e..bcfe557f1 100644
--- a/src/FDM/JSBSim/FGFDMExec.cpp
+++ b/src/FDM/JSBSim/FGFDMExec.cpp
@@ -71,7 +71,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGFDMExec.cpp,v 1.91 2011/04/05 20:20:21 andgi Exp $";
+static const char *IdSrc = "$Id: FGFDMExec.cpp,v 1.95 2011/05/20 10:35:25 jberndt Exp $";
 static const char *IdHdr = ID_FDMEXEC;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -228,19 +228,19 @@ bool FGFDMExec::Allocate(void)
   // Schedule a model. The second arg (the integer) is the pass number. For
   // instance, the atmosphere model could get executed every fifth pass it is called.
   
-  Schedule(Input,           1);
-  Schedule(Atmosphere,      1);
-  Schedule(FCS,             1);
-  Schedule(Propulsion,      1);
-  Schedule(MassBalance,     1);
-  Schedule(Aerodynamics,    1);
-  Schedule(Inertial,        1);
-  Schedule(GroundReactions, 1);
-  Schedule(ExternalReactions, 1);
-  Schedule(BuoyantForces,   1);
-  Schedule(Aircraft,        1);
-  Schedule(Propagate,       1);
-  Schedule(Auxiliary,       1);
+  Schedule(Input,           1);   // Input model is Models[0]
+  Schedule(Atmosphere,      1);   // Input model is Models[1]
+  Schedule(FCS,             1);   // Input model is Models[2]
+  Schedule(Propulsion,      1);   // Input model is Models[3]
+  Schedule(MassBalance,     1);   // Input model is Models[4]
+  Schedule(Aerodynamics,    1);   // Input model is Models[5]
+  Schedule(Inertial,        1);   // Input model is Models[6]
+  Schedule(GroundReactions, 1);   // Input model is Models[7]
+  Schedule(ExternalReactions, 1); // Input model is Models[8]
+  Schedule(BuoyantForces,   1);   // Input model is Models[9]
+  Schedule(Aircraft,        1);   // Input model is Models[10]
+  Schedule(Propagate,       1);   // Input model is Models[11]
+  Schedule(Auxiliary,       1);   // Input model is Models[12]
 
   // Initialize models so they can communicate with each other
 
@@ -329,10 +329,9 @@ bool FGFDMExec::Run(void)
   if (Script != 0 && !IntegrationSuspended()) success = Script->RunScript();
 
   vector <FGModel*>::iterator it;
-  for (it = Models.begin(); it != Models.end(); ++it) (*it)->Run();
+  for (it = Models.begin(); it != Models.end(); ++it) (*it)->Run(holding);
 
-  Frame++;
-  if (!Holding()) IncrTime();
+  IncrTime();
   if (Terminate) success = false;
 
   return (success);
@@ -359,36 +358,12 @@ void FGFDMExec::Initialize(FGInitialCondition *FGIC)
 
   Propagate->SetInitialState( FGIC );
 
-  Atmosphere->Run();
+  Atmosphere->Run(false);
   Atmosphere->SetWindNED( FGIC->GetWindNFpsIC(),
                           FGIC->GetWindEFpsIC(),
                           FGIC->GetWindDFpsIC() );
 
-  FGColumnVector3 vAeroUVW;
-
-  //ToDo: move this to the Auxiliary class !?
-
-  vAeroUVW = Propagate->GetUVW() + Propagate->GetTl2b()*Atmosphere->GetTotalWindNED();
-
-  double alpha, beta;
-  if (vAeroUVW(eW) != 0.0)
-    alpha = vAeroUVW(eU)*vAeroUVW(eU) > 0.0 ? atan2(vAeroUVW(eW), vAeroUVW(eU)) : 0.0;
-  else
-    alpha = 0.0;
-  if (vAeroUVW(eV) != 0.0)
-    beta = vAeroUVW(eU)*vAeroUVW(eU)+vAeroUVW(eW)*vAeroUVW(eW) > 0.0 ? atan2(vAeroUVW(eV), (fabs(vAeroUVW(eU))/vAeroUVW(eU))*sqrt(vAeroUVW(eU)*vAeroUVW(eU) + vAeroUVW(eW)*vAeroUVW(eW))) : 0.0;
-  else
-    beta = 0.0;
-
-  Auxiliary->SetAB(alpha, beta);
-
-  double Vt = vAeroUVW.Magnitude();
-  Auxiliary->SetVt(Vt);
-
-  Auxiliary->SetMach(Vt/Atmosphere->GetSoundSpeed());
-
-  double qbar = 0.5*Vt*Vt*Atmosphere->GetDensity();
-  Auxiliary->Setqbar(qbar);
+  Auxiliary->Run(false);
 }
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -675,7 +650,7 @@ bool FGFDMExec::LoadModel(const string& model, bool addModelToPath)
     modelLoaded = true;
 
     if (debug_lvl > 0) {
-      MassBalance->Run(); // Update all mass properties for the report.
+      MassBalance->Run(false); // Update all mass properties for the report.
       MassBalance->GetMassPropertiesReport();
 
       cout << endl << fgblue << highint
@@ -968,38 +943,6 @@ void FGFDMExec::DoTrim(int mode)
   sim_time = saved_time;
 }
 
-//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-/*
-void FGFDMExec::DoTrimAnalysis(int mode)
-{
-  double saved_time;
-  if (Constructing) return;
-
-  if (mode < 0 || mode > JSBSim::taNone) {
-    cerr << endl << "Illegal trimming mode!" << endl << endl;
-    return;
-  }
-  saved_time = sim_time;
-
-  FGTrimAnalysis trimAnalysis(this, (JSBSim::TrimAnalysisMode)mode);
-
-  if ( !trimAnalysis.Load(IC->GetInitFile(), false) ) {
-    cerr << "A problem occurred with trim configuration file " << trimAnalysis.Load(IC->GetInitFile()) << endl;
-    exit(-1);
-  }
-
-  bool result = trimAnalysis.DoTrim();
-
-  if ( !result ) cerr << endl << "Trim Failed" << endl << endl;
-
-  trimAnalysis.Report();
-  Setsim_time(saved_time);
-
-  EnableOutput();
-  cout << "\nOutput: " << GetOutputFileName() << endl;
-
-}
-*/
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 void FGFDMExec::UseAtmosphereMSIS(void)
@@ -1010,6 +953,8 @@ void FGFDMExec::UseAtmosphereMSIS(void)
     cerr << fgred << "MSIS Atmosphere model init failed" << fgdef << endl;
     Error+=1;
   }
+  Models[1] = Atmosphere; // Reassign the atmosphere model that has already been scheduled
+                          // to the new atmosphere.
   delete oldAtmosphere;
 }
 
@@ -1024,6 +969,8 @@ void FGFDMExec::UseAtmosphereMars(void)
     cerr << fgred << "Mars Atmosphere model init failed" << fgdef << endl;
     Error+=1;
   }
+  Models[1] = Atmosphere; // Reassign the atmosphere model that has already been scheduled
+                          // to the new atmosphere.
   delete oldAtmosphere;
 */
 }
diff --git a/src/FDM/JSBSim/FGFDMExec.h b/src/FDM/JSBSim/FGFDMExec.h
index 5f103fe15..e745b2224 100644
--- a/src/FDM/JSBSim/FGFDMExec.h
+++ b/src/FDM/JSBSim/FGFDMExec.h
@@ -58,7 +58,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_FDMEXEC "$Id: FGFDMExec.h,v 1.63 2011/02/19 16:44:41 jberndt Exp $"
+#define ID_FDMEXEC "$Id: FGFDMExec.h,v 1.64 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -181,7 +181,7 @@ CLASS DOCUMENTATION
                                 property actually maps toa function call of DoTrim().
 
     @author Jon S. Berndt
-    @version $Revision: 1.63 $
+    @version $Revision: 1.64 $
 */
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -432,7 +432,6 @@ public:
   * - tTurn
   * - tNone  */
   void DoTrim(int mode);
-//  void DoTrimAnalysis(int mode);
 
   /// Disables data logging to all outputs.
   void DisableOutput(void);
@@ -522,10 +521,12 @@ public:
       @return the string representing the root (base) JSBSim directory. */
   const string& GetRootDir(void) const {return RootDir;}
 
-  /** Increments the simulation time.
+  /** Increments the simulation time if not in Holding mode. The Frame counter
+      is also incremented.
       @return the new simulation time.     */
   double IncrTime(void) {
-    sim_time += dT;
+    if (!holding) sim_time += dT;
+    Frame++;
     return sim_time;
   }
 
diff --git a/src/FDM/JSBSim/FGJSBBase.cpp b/src/FDM/JSBSim/FGJSBBase.cpp
index a361a37d2..d34075e70 100644
--- a/src/FDM/JSBSim/FGJSBBase.cpp
+++ b/src/FDM/JSBSim/FGJSBBase.cpp
@@ -44,7 +44,7 @@ INCLUDES
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGJSBBase.cpp,v 1.29 2010/03/18 13:19:21 jberndt Exp $";
+static const char *IdSrc = "$Id: FGJSBBase.cpp,v 1.30 2011/06/13 11:47:04 jberndt Exp $";
 static const char *IdHdr = ID_JSBBASE;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -89,7 +89,9 @@ const double FGJSBBase::in3tom3 = 1.638706E-5;
 const double FGJSBBase::m3toft3 = 1.0/(fttom*fttom*fttom);
 const double FGJSBBase::inhgtopa = 3386.38;
 const double FGJSBBase::fttom = 0.3048;
-double FGJSBBase::Reng = 1716.0;
+double FGJSBBase::Reng = 1716.56;   // Gas constant for Air (ft-lb/slug-R)
+double FGJSBBase::Rstar = 1545.348; // Universal gas constant
+double FGJSBBase::Mair = 28.9645;   //
 const double FGJSBBase::SHRatio = 1.40;
 
 // Note that definition of lbtoslug by the inverse of slugtolb and not
diff --git a/src/FDM/JSBSim/FGJSBBase.h b/src/FDM/JSBSim/FGJSBBase.h
index 2049a3cad..69d9f9c09 100644
--- a/src/FDM/JSBSim/FGJSBBase.h
+++ b/src/FDM/JSBSim/FGJSBBase.h
@@ -63,7 +63,7 @@ namespace std
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_JSBBASE "$Id: FGJSBBase.h,v 1.30 2010/07/01 23:13:19 jberndt Exp $"
+#define ID_JSBBASE "$Id: FGJSBBase.h,v 1.32 2011/06/13 11:47:04 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -79,7 +79,7 @@ CLASS DOCUMENTATION
 *   This class provides universal constants, utility functions, messaging
 *   functions, and enumerated constants to JSBSim.
     @author Jon S. Berndt
-    @version $Id: FGJSBBase.h,v 1.30 2010/07/01 23:13:19 jberndt Exp $
+    @version $Id: FGJSBBase.h,v 1.32 2011/06/13 11:47:04 jberndt Exp $
 */
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -92,7 +92,7 @@ public:
   FGJSBBase() {};
 
   /// Destructor for FGJSBBase.
-  ~FGJSBBase() {};
+  virtual ~FGJSBBase() {};
 
   /// JSBSim Message structure
   class Message {
@@ -327,6 +327,8 @@ protected:
   static const double inhgtopa;
   static const double fttom;
   static double Reng;         // Specific Gas Constant,ft^2/(sec^2*R)
+  static double Rstar;
+  static double Mair;
   static const double SHRatio;
   static const double lbtoslug;
   static const double slugtolb;
diff --git a/src/FDM/JSBSim/JSBSim.cxx b/src/FDM/JSBSim/JSBSim.cxx
index 3e6cdf7bd..3b5199599 100644
--- a/src/FDM/JSBSim/JSBSim.cxx
+++ b/src/FDM/JSBSim/JSBSim.cxx
@@ -140,7 +140,7 @@ FGJSBsim::FGJSBsim( double dt )
     if( TURBULENCE_TYPE_NAMES.empty() ) {
         TURBULENCE_TYPE_NAMES["ttNone"]     = FGAtmosphere::ttNone;
         TURBULENCE_TYPE_NAMES["ttStandard"] = FGAtmosphere::ttStandard;
-        TURBULENCE_TYPE_NAMES["ttBerndt"]   = FGAtmosphere::ttBerndt;
+//      TURBULENCE_TYPE_NAMES["ttBerndt"]   = FGAtmosphere::ttBerndt;
         TURBULENCE_TYPE_NAMES["ttCulp"]     = FGAtmosphere::ttCulp;
         TURBULENCE_TYPE_NAMES["ttMilspec"]  = FGAtmosphere::ttMilspec;
         TURBULENCE_TYPE_NAMES["ttTustin"]   = FGAtmosphere::ttTustin;
@@ -672,9 +672,9 @@ bool FGJSBsim::copy_to_JSBsim()
 
     Atmosphere->SetTurbType((FGAtmosphere::tType)TURBULENCE_TYPE_NAMES[turbulence_model->getStringValue()]);
     switch( Atmosphere->GetTurbType() ) {
+//      case FGAtmosphere::ttBerndt:
         case FGAtmosphere::ttStandard:
-        case FGAtmosphere::ttCulp:
-        case FGAtmosphere::ttBerndt: {
+        case FGAtmosphere::ttCulp: {
             double tmp = turbulence_gain->getDoubleValue();
             Atmosphere->SetTurbGain(tmp * tmp * 100.0);
             Atmosphere->SetTurbRate(turbulence_rate->getDoubleValue());
diff --git a/src/FDM/JSBSim/initialization/FGInitialCondition.cpp b/src/FDM/JSBSim/initialization/FGInitialCondition.cpp
index 00a3840f1..d1b65f1bc 100644
--- a/src/FDM/JSBSim/initialization/FGInitialCondition.cpp
+++ b/src/FDM/JSBSim/initialization/FGInitialCondition.cpp
@@ -61,7 +61,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGInitialCondition.cpp,v 1.61 2011/05/20 00:47:03 bcoconni Exp $";
+static const char *IdSrc = "$Id: FGInitialCondition.cpp,v 1.63 2011/06/13 10:30:22 bcoconni Exp $";
 static const char *IdHdr = ID_INITIALCONDITION;
 
 //******************************************************************************
@@ -189,7 +189,7 @@ void FGInitialCondition::SetVequivalentKtsIC(double ve)
   double altitudeASL = position.GetRadius() - sea_level_radius;
   double rho = fdmex->GetAtmosphere()->GetDensity(altitudeASL);
   double rhoSL = fdmex->GetAtmosphere()->GetDensitySL();
-  SetVtrueFpsIC(ve*ktstofps/sqrt(rho/rhoSL));
+  SetVtrueFpsIC(ve*ktstofps*sqrt(rhoSL/rho));
   lastSpeedSet = setve;
 }
 
@@ -324,7 +324,7 @@ void FGInitialCondition::SetClimbRateFpsIC(double hdot)
   FGColumnVector3 _WIND_NED = _vt_NED - vUVW_NED;
   double hdot0 = -_vt_NED(eW);
 
-  if (fabs(hdot0) < vt) {
+  if (fabs(hdot0) < vt) { // Is this check really needed ?
     double scale = sqrt((vt*vt-hdot*hdot)/(vt*vt-hdot0*hdot0));
     _vt_NED(eU) *= scale;
     _vt_NED(eV) *= scale;
@@ -606,7 +606,7 @@ void FGInitialCondition::SetHeadWindKtsIC(double head)
   FGColumnVector3 _vWIND_NED = _vt_NED - vUVW_NED;
   FGColumnVector3 _vHEAD(cos(psi), sin(psi), 0.);
 
-  // Gram-Schmidt process is used to remove the existing cross wind component
+  // Gram-Schmidt process is used to remove the existing head wind component
   _vWIND_NED -= DotProduct(_vWIND_NED, _vHEAD) * _vHEAD;
   // which is now replaced by the new value.
   _vWIND_NED += head * _vHEAD;
@@ -707,7 +707,7 @@ void FGInitialCondition::SetAltitudeASLFtIC(double alt)
       SetVtrueFpsIC(mach0 * soundSpeed);
       break;
     case setve:
-      SetVtrueFpsIC(ve0 * sqrt(rho/rhoSL));
+      SetVtrueFpsIC(ve0 * sqrt(rhoSL/rho));
       break;
     default: // Make the compiler stop complaining about missing enums
       break;
@@ -1088,7 +1088,7 @@ bool FGInitialCondition::Load_v2(void)
   // the given orientation and knowledge of the Earth position angle.
   // This could be done using matrices (where in the subscript "b/a",
   // it is meant "b with respect to a", and where b=body frame,
-  // i=inertial frame, and e=ecef frame) as:
+  // i=inertial frame, l=local NED frame and e=ecef frame) as:
   //
   // C_b/l =  C_b/e * C_e/l
   //
diff --git a/src/FDM/JSBSim/math/FGTable.cpp b/src/FDM/JSBSim/math/FGTable.cpp
index 0780739c9..08396eaae 100644
--- a/src/FDM/JSBSim/math/FGTable.cpp
+++ b/src/FDM/JSBSim/math/FGTable.cpp
@@ -47,7 +47,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGTable.cpp,v 1.27 2010/10/21 11:09:56 jberndt Exp $";
+static const char *IdSrc = "$Id: FGTable.cpp,v 1.28 2011/06/13 12:07:10 jberndt Exp $";
 static const char *IdHdr = ID_TABLE;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -559,6 +559,8 @@ void FGTable::operator<<(istream& in_stream)
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
+// Put some error handling in here if trying to access out of range row, col.
+
 FGTable& FGTable::operator<<(const double n)
 {
   Data[rowCounter][colCounter] = n;
diff --git a/src/FDM/JSBSim/math/FGTable.h b/src/FDM/JSBSim/math/FGTable.h
index 3d2224981..1989de4c2 100644
--- a/src/FDM/JSBSim/math/FGTable.h
+++ b/src/FDM/JSBSim/math/FGTable.h
@@ -47,7 +47,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_TABLE "$Id: FGTable.h,v 1.13 2011/04/05 20:20:21 andgi Exp $"
+#define ID_TABLE "$Id: FGTable.h,v 1.14 2011/06/13 11:46:08 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -233,7 +233,7 @@ combustion_efficiency = Lookup_Combustion_Efficiency->GetValue(equivalence_ratio
 @endcode
 
 @author Jon S. Berndt
-@version $Id: FGTable.h,v 1.13 2011/04/05 20:20:21 andgi Exp $
+@version $Id: FGTable.h,v 1.14 2011/06/13 11:46:08 jberndt Exp $
 */
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -284,12 +284,17 @@ public:
   FGTable& operator<<(const double n);
   FGTable& operator<<(const int n);
 
-  inline double GetElement(int r, int c) {return Data[r][c];}
-  inline double GetElement(int r, int c, int t);
+  inline double GetElement(int r, int c) const {return Data[r][c];}
+//  inline double GetElement(int r, int c, int t);
+
+  double operator()(unsigned int r, unsigned int c) const {return GetElement(r, c);}
+//  double operator()(unsigned int r, unsigned int c, unsigned int t) {GetElement(r, c, t);}
 
   void SetRowIndexProperty(FGPropertyManager *node) {lookupProperty[eRow] = node;}
   void SetColumnIndexProperty(FGPropertyManager *node) {lookupProperty[eColumn] = node;}
 
+  unsigned int GetNumRows() const {return nRows;}
+
   void Print(void);
 
   std::string GetName(void) const {return Name;}
diff --git a/src/FDM/JSBSim/models/FGAerodynamics.cpp b/src/FDM/JSBSim/models/FGAerodynamics.cpp
index 0f08c0160..4208ef626 100644
--- a/src/FDM/JSBSim/models/FGAerodynamics.cpp
+++ b/src/FDM/JSBSim/models/FGAerodynamics.cpp
@@ -52,7 +52,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGAerodynamics.cpp,v 1.37 2011/03/11 13:02:26 jberndt Exp $";
+static const char *IdSrc = "$Id: FGAerodynamics.cpp,v 1.38 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_AERODYNAMICS;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -132,11 +132,11 @@ bool FGAerodynamics::InitModel(void)
 }
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-bool FGAerodynamics::Run(void)
+bool FGAerodynamics::Run(bool Holding)
 {
 
-  if (FGModel::Run()) return true;
-  if (FDMExec->Holding()) return false; // if paused don't execute
+  if (FGModel::Run(Holding)) return true;
+  if (Holding) return false; // if paused don't execute
 
   unsigned int axis_ctr, ctr;
   const double alpha=FDMExec->GetAuxiliary()->Getalpha();
diff --git a/src/FDM/JSBSim/models/FGAerodynamics.h b/src/FDM/JSBSim/models/FGAerodynamics.h
index c6638b411..87744e86e 100644
--- a/src/FDM/JSBSim/models/FGAerodynamics.h
+++ b/src/FDM/JSBSim/models/FGAerodynamics.h
@@ -52,7 +52,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_AERODYNAMICS "$Id: FGAerodynamics.h,v 1.22 2011/03/11 13:02:26 jberndt Exp $"
+#define ID_AERODYNAMICS "$Id: FGAerodynamics.h,v 1.23 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -109,7 +109,7 @@ CLASS DOCUMENTATION
     Systems may NOT be combined, or a load error will occur.
 
     @author Jon S. Berndt, Tony Peden
-    @version $Revision: 1.22 $
+    @version $Revision: 1.23 $
 */
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -129,8 +129,13 @@ public:
   bool InitModel(void);
 
   /** Runs the Aerodynamics model; called by the Executive
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
       @return false if no error */
-  bool Run(void);
+  bool Run(bool Holding);
 
   /** Loads the Aerodynamics model.
       The Load function for this class expects the XML parser to
diff --git a/src/FDM/JSBSim/models/FGAircraft.cpp b/src/FDM/JSBSim/models/FGAircraft.cpp
index e2adbe44c..7b0f3705a 100644
--- 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 1.30 2010/11/29 12:33:57 jberndt Exp $";
+static const char *IdSrc = "$Id: FGAircraft.cpp,v 1.31 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_AIRCRAFT;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -101,17 +101,15 @@ FGAircraft::~FGAircraft()
 
 bool FGAircraft::InitModel(void)
 {
-  if (!FGModel::InitModel()) return false;
-
   return true;
 }
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-bool FGAircraft::Run(void)
+bool FGAircraft::Run(bool Holding)
 {
-  if (FGModel::Run()) return true;
-  if (FDMExec->Holding()) return false;
+  if (FGModel::Run(Holding)) return true;
+  if (Holding) return false;
 
   RunPreFunctions();
 
diff --git a/src/FDM/JSBSim/models/FGAircraft.h b/src/FDM/JSBSim/models/FGAircraft.h
index c3060db37..684f1dd2e 100644
--- a/src/FDM/JSBSim/models/FGAircraft.h
+++ b/src/FDM/JSBSim/models/FGAircraft.h
@@ -49,7 +49,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_AIRCRAFT "$Id: FGAircraft.h,v 1.16 2010/11/18 12:38:06 jberndt Exp $"
+#define ID_AIRCRAFT "$Id: FGAircraft.h,v 1.17 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -90,7 +90,7 @@ CLASS DOCUMENTATION
 @endcode
 
     @author Jon S. Berndt
-    @version $Id: FGAircraft.h,v 1.16 2010/11/18 12:38:06 jberndt Exp $
+    @version $Id: FGAircraft.h,v 1.17 2011/05/20 03:18:36 jberndt Exp $
     @see Cooke, Zyda, Pratt, and McGhee, "NPSNET: Flight Simulation Dynamic Modeling
 	   Using Quaternions", Presence, Vol. 1, No. 4, pp. 404-420  Naval Postgraduate
 	   School, January 1994
@@ -118,9 +118,14 @@ public:
   ~FGAircraft();
 
   /** Runs the Aircraft model; called by the Executive
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
       @see JSBSim.cpp documentation
       @return false if no error */
-  bool Run(void);
+  bool Run(bool Holding);
 
   bool InitModel(void);
 
diff --git a/src/FDM/JSBSim/models/FGAtmosphere.cpp b/src/FDM/JSBSim/models/FGAtmosphere.cpp
index 992e7952e..990adb882 100644
--- 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 1.42 2011/02/18 12:44:16 jberndt Exp $";
+static const char *IdSrc = "$Id: FGAtmosphere.cpp,v 1.45 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_ATMOSPHERE;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -84,8 +84,7 @@ FGAtmosphere::FGAtmosphere(FGFDMExec* fdmex) : FGModel(fdmex)
   htab[7]=278385.0; //ft.
 
   MagnitudedAccelDt = MagnitudeAccel = Magnitude = 0.0;
-//  SetTurbType( ttCulp );
-  SetTurbType( ttNone );
+  SetTurbType( ttMilspec );
   TurbGain = 1.0;
   TurbRate = 10.0;
   Rhythmicity = 0.1;
@@ -132,8 +131,6 @@ FGAtmosphere::~FGAtmosphere()
 
 bool FGAtmosphere::InitModel(void)
 {
-  if (!FGModel::InitModel()) return false;
-
   UseInternal();  // this is the default
 
   Calculate(h);
@@ -151,10 +148,10 @@ bool FGAtmosphere::InitModel(void)
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-bool FGAtmosphere::Run(void)
+bool FGAtmosphere::Run(bool Holding)
 {
-  if (FGModel::Run()) return true;
-  if (FDMExec->Holding()) return false;
+  if (FGModel::Run(Holding)) return true;
+  if (Holding) return false;
 
   RunPreFunctions();
 
@@ -483,45 +480,7 @@ void FGAtmosphere::Turbulence(void)
 
     break;
   }
-  case ttBerndt: { // This is very experimental and incomplete at the moment.
-
-    vDirectiondAccelDt(eX) = GaussianRandomNumber();
-    vDirectiondAccelDt(eY) = GaussianRandomNumber();
-    vDirectiondAccelDt(eZ) = GaussianRandomNumber();
-/*
-    MagnitudedAccelDt = GaussianRandomNumber();
-    MagnitudeAccel    += MagnitudedAccelDt * DeltaT;
-    Magnitude         += MagnitudeAccel * DeltaT;
-*/
-    Magnitude         += GaussianRandomNumber() * DeltaT;
-
-    vDirectiondAccelDt.Normalize();
-    vDirectionAccel += TurbRate * vDirectiondAccelDt * DeltaT;
-    vDirectionAccel.Normalize();
-    vDirection      += vDirectionAccel*DeltaT;
-
-    // Diminish z-vector within two wingspans of the ground
-    if (HOverBMAC < 2.0) vDirection(eZ) *= HOverBMAC / 2.0;
-
-    vDirection.Normalize();
-
-    vTurbulenceNED = TurbGain*Magnitude * vDirection;
-    vTurbulenceGrad = TurbGain*MagnitudeAccel * vDirection;
-
-    vBodyTurbGrad = Tl2b * vTurbulenceGrad;
-    vTurbPQR(eP) = vBodyTurbGrad(eY) / wingspan;
-    if (HTailArm > 0)
-      vTurbPQR(eQ) = vBodyTurbGrad(eZ) / HTailArm;
-    else
-      vTurbPQR(eQ) = vBodyTurbGrad(eZ) / 10.0;
 
-    if (VTailArm > 0)
-      vTurbPQR(eR) = vBodyTurbGrad(eX) / VTailArm;
-    else
-      vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
-
-    break;
-  }
   case ttCulp: { 
 
     vTurbPQR(eP) = wind_from_clockwise;
diff --git a/src/FDM/JSBSim/models/FGAtmosphere.h b/src/FDM/JSBSim/models/FGAtmosphere.h
index 3dd6fa322..d2c8b5dbe 100644
--- a/src/FDM/JSBSim/models/FGAtmosphere.h
+++ b/src/FDM/JSBSim/models/FGAtmosphere.h
@@ -50,7 +50,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_ATMOSPHERE "$Id: FGAtmosphere.h,v 1.24 2010/11/18 12:38:06 jberndt Exp $"
+#define ID_ATMOSPHERE "$Id: FGAtmosphere.h,v 1.26 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -64,7 +64,7 @@ CLASS DOCUMENTATION
 
 /** Models the 1976 Standard Atmosphere.
     @author Tony Peden, Jon Berndt
-    @version $Id: FGAtmosphere.h,v 1.24 2010/11/18 12:38:06 jberndt Exp $
+    @version $Id: FGAtmosphere.h,v 1.26 2011/05/20 03:18:36 jberndt Exp $
     @see Anderson, John D. "Introduction to Flight, Third Edition", McGraw-Hill,
          1989, ISBN 0-07-001641-0
 
@@ -132,102 +132,107 @@ public:
   /// Destructor
   ~FGAtmosphere();
   /** Runs the Atmosphere model; called by the Executive
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
       @return false if no error */
-  bool Run(void);
+  bool Run(bool Holding);
   bool InitModel(void);
-  enum tType {ttNone, ttStandard, ttBerndt, ttCulp, ttMilspec, ttTustin} turbType;
+  enum tType {ttNone, ttStandard, ttCulp, ttMilspec, ttTustin} turbType;
 
   /// Returns the temperature in degrees Rankine.
-  double GetTemperature(void) const {return *temperature;}
+  virtual double GetTemperature(void) const {return *temperature;}
   /** Returns the density in slugs/ft^3.
       <i>This function may <b>only</b> be used if Run() is called first.</i> */
-  double GetDensity(void)  const {return *density;}
+  virtual double GetDensity(void)  const {return *density;}
   /// Returns the pressure in psf.
-  double GetPressure(void)  const {return *pressure;}
+  virtual double GetPressure(void)  const {return *pressure;}
   /// Returns the standard pressure at a specified altitude
-  double GetPressure(double altitude);
+  virtual double GetPressure(double altitude);
   /// Returns the standard temperature at a specified altitude
-  double GetTemperature(double altitude);
+  virtual double GetTemperature(double altitude);
   /// Returns the standard density at a specified altitude
-  double GetDensity(double altitude);
+  virtual double GetDensity(double altitude);
   /// Returns the speed of sound in ft/sec.
-  double GetSoundSpeed(void) const {return soundspeed;}
+  virtual double GetSoundSpeed(void) const {return soundspeed;}
   /// Returns the absolute viscosity.
-  double GetAbsoluteViscosity(void) const {return intViscosity;}
+  virtual double GetAbsoluteViscosity(void) const {return intViscosity;}
   /// Returns the kinematic viscosity.
-  double GetKinematicViscosity(void) const {return intKinematicViscosity;}
+  virtual double GetKinematicViscosity(void) const {return intKinematicViscosity;}
 
   /// Returns the sea level temperature in degrees Rankine.
-  double GetTemperatureSL(void) const { return SLtemperature; }
+  virtual double GetTemperatureSL(void) const { return SLtemperature; }
   /// Returns the sea level density in slugs/ft^3
-  double GetDensitySL(void)  const { return SLdensity; }
+  virtual double GetDensitySL(void)  const { return SLdensity; }
   /// Returns the sea level pressure in psf.
-  double GetPressureSL(void) const { return SLpressure; }
+  virtual double GetPressureSL(void) const { return SLpressure; }
   /// Returns the sea level speed of sound in ft/sec.
-  double GetSoundSpeedSL(void) const { return SLsoundspeed; }
+  virtual double GetSoundSpeedSL(void) const { return SLsoundspeed; }
 
   /// Returns the ratio of at-altitude temperature over the sea level value.
-  double GetTemperatureRatio(void) const { return (*temperature)*rSLtemperature; }
+  virtual double GetTemperatureRatio(void) const { return (*temperature)*rSLtemperature; }
   /// Returns the ratio of at-altitude density over the sea level value.
-  double GetDensityRatio(void) const { return (*density)*rSLdensity; }
+  virtual double GetDensityRatio(void) const { return (*density)*rSLdensity; }
   /// Returns the ratio of at-altitude pressure over the sea level value.
-  double GetPressureRatio(void) const { return (*pressure)*rSLpressure; }
+  virtual double GetPressureRatio(void) const { return (*pressure)*rSLpressure; }
   /// Returns the ratio of at-altitude sound speed over the sea level value.
-  double GetSoundSpeedRatio(void) const { return soundspeed*rSLsoundspeed; }
+  virtual double GetSoundSpeedRatio(void) const { return soundspeed*rSLsoundspeed; }
 
   /// Tells the simulator to use an externally calculated atmosphere model.
-  void UseExternal(void);
+  virtual void UseExternal(void);
   /// Tells the simulator to use the internal atmosphere model.
-  void UseInternal(void);  //this is the default
+  virtual void UseInternal(void);  //this is the default
   /// Gets the boolean that tells if the external atmosphere model is being used.
-  bool External(void) { return useExternal; }
+  virtual bool External(void) { return useExternal; }
 
   /// Provides the external atmosphere model with an interface to set the temperature.
-  void SetExTemperature(double t)  { exTemperature=t; }
+  virtual void SetExTemperature(double t)  { exTemperature=t; }
   /// Provides the external atmosphere model with an interface to set the density.
-  void SetExDensity(double d)      { exDensity=d; }
+  virtual void SetExDensity(double d)      { exDensity=d; }
   /// Provides the external atmosphere model with an interface to set the pressure.
-  void SetExPressure(double p)     { exPressure=p; }
+  virtual void SetExPressure(double p)     { exPressure=p; }
 
   /// Sets the temperature deviation at sea-level in degrees Fahrenheit
-  void SetSLTempDev(double d)  { T_dev_sl = d; }
+  virtual void SetSLTempDev(double d)  { T_dev_sl = d; }
   /// Gets the temperature deviation at sea-level in degrees Fahrenheit
-  double GetSLTempDev(void) const { return T_dev_sl; }
+  virtual double GetSLTempDev(void) const { return T_dev_sl; }
   /// Sets the current delta-T in degrees Fahrenheit
-  void SetDeltaT(double d)  { delta_T = d; }
+  virtual void SetDeltaT(double d)  { delta_T = d; }
   /// Gets the current delta-T in degrees Fahrenheit
-  double GetDeltaT(void) const  { return delta_T; }
+  virtual double GetDeltaT(void) const  { return delta_T; }
   /// Gets the at-altitude temperature deviation in degrees Fahrenheit
-  double GetTempDev(void) const { return T_dev; }
+  virtual double GetTempDev(void) const { return T_dev; }
   /// Gets the density altitude in feet
-  double GetDensityAltitude(void) const { return density_altitude; }
+  virtual double GetDensityAltitude(void) const { return density_altitude; }
 
   // TOTAL WIND access functions (wind + gust + turbulence)
 
   /// Retrieves the total wind components in NED frame.
-  const FGColumnVector3& GetTotalWindNED(void) const { return vTotalWindNED; }
+  virtual const FGColumnVector3& GetTotalWindNED(void) const { return vTotalWindNED; }
 
   /// Retrieves a total wind component in NED frame.
-  double GetTotalWindNED(int idx) const {return vTotalWindNED(idx);}
+  virtual double GetTotalWindNED(int idx) const {return vTotalWindNED(idx);}
 
   // WIND access functions
 
   /// Sets the wind components in NED frame.
-  void SetWindNED(double wN, double wE, double wD) { vWindNED(1)=wN; vWindNED(2)=wE; vWindNED(3)=wD;}
+  virtual void SetWindNED(double wN, double wE, double wD) { vWindNED(1)=wN; vWindNED(2)=wE; vWindNED(3)=wD;}
 
   /// Sets a wind component in NED frame.
-  void SetWindNED(int idx, double wind) { vWindNED(idx)=wind;}
+  virtual void SetWindNED(int idx, double wind) { vWindNED(idx)=wind;}
 
   /// Retrieves the wind components in NED frame.
-  FGColumnVector3& GetWindNED(void) { return vWindNED; }
+  virtual FGColumnVector3& GetWindNED(void) { return vWindNED; }
 
   /// Retrieves a wind component in NED frame.
-  double GetWindNED(int idx) const {return vWindNED(idx);}
+  virtual double GetWindNED(int idx) const {return vWindNED(idx);}
 
   /** Retrieves the direction that the wind is coming from.
       The direction is defined as north=0 and increases counterclockwise.
       The wind heading is returned in radians.*/
-  double GetWindPsi(void) const { return psiw; }
+  virtual double GetWindPsi(void) const { return psiw; }
 
   /** Sets the direction that the wind is coming from.
       The direction is defined as north=0 and increases counterclockwise to 2*pi (radians). The
@@ -235,56 +240,56 @@ public:
       sets the vWindNED vector components based on the supplied direction. The magnitude of
       the wind set in the vector is preserved (assuming the vertical component is non-zero).
       @param dir wind direction in the horizontal plane, in radians.*/
-  void SetWindPsi(double dir);
+  virtual void SetWindPsi(double dir);
 
-  void SetWindspeed(double speed);
+  virtual void SetWindspeed(double speed);
 
-  double GetWindspeed(void) const;
+  virtual double GetWindspeed(void) const;
 
   // GUST access functions
 
   /// Sets a gust component in NED frame.
-  void SetGustNED(int idx, double gust) { vGustNED(idx)=gust;}
+  virtual void SetGustNED(int idx, double gust) { vGustNED(idx)=gust;}
 
   /// Sets a turbulence component in NED frame.
-  void SetTurbNED(int idx, double turb) { vTurbulenceNED(idx)=turb;}
+  virtual void SetTurbNED(int idx, double turb) { vTurbulenceNED(idx)=turb;}
 
   /// Sets the gust components in NED frame.
-  void SetGustNED(double gN, double gE, double gD) { vGustNED(eNorth)=gN; vGustNED(eEast)=gE; vGustNED(eDown)=gD;}
+  virtual void SetGustNED(double gN, double gE, double gD) { vGustNED(eNorth)=gN; vGustNED(eEast)=gE; vGustNED(eDown)=gD;}
 
   /// Retrieves a gust component in NED frame.
-  double GetGustNED(int idx) const {return vGustNED(idx);}
+  virtual double GetGustNED(int idx) const {return vGustNED(idx);}
 
   /// Retrieves a turbulence component in NED frame.
-  double GetTurbNED(int idx) const {return vTurbulenceNED(idx);}
+  virtual double GetTurbNED(int idx) const {return vTurbulenceNED(idx);}
 
   /// Retrieves the gust components in NED frame.
-  FGColumnVector3& GetGustNED(void) {return vGustNED;}
+  virtual FGColumnVector3& GetGustNED(void) {return vGustNED;}
 
   /** Turbulence models available: ttNone, ttStandard, ttBerndt, ttCulp, ttMilspec, ttTustin */
-  void   SetTurbType(tType tt) {turbType = tt;}
-  tType  GetTurbType() const {return turbType;}
+  virtual void   SetTurbType(tType tt) {turbType = tt;}
+  virtual tType  GetTurbType() const {return turbType;}
 
-  void   SetTurbGain(double tg) {TurbGain = tg;}
-  double GetTurbGain() const {return TurbGain;}
+  virtual void   SetTurbGain(double tg) {TurbGain = tg;}
+  virtual double GetTurbGain() const {return TurbGain;}
 
-  void   SetTurbRate(double tr) {TurbRate = tr;}
-  double GetTurbRate() const {return TurbRate;}
+  virtual void   SetTurbRate(double tr) {TurbRate = tr;}
+  virtual double GetTurbRate() const {return TurbRate;}
 
-  void   SetRhythmicity(double r) {Rhythmicity=r;}
-  double GetRhythmicity() const {return Rhythmicity;}
+  virtual void   SetRhythmicity(double r) {Rhythmicity=r;}
+  virtual double GetRhythmicity() const {return Rhythmicity;}
 
-  double GetTurbPQR(int idx) const {return vTurbPQR(idx);}
-  double GetTurbMagnitude(void) const {return Magnitude;}
-  const FGColumnVector3& GetTurbDirection(void) const {return vDirection;}
-  const FGColumnVector3& GetTurbPQR(void) const {return vTurbPQR;}
+  virtual double GetTurbPQR(int idx) const {return vTurbPQR(idx);}
+  virtual double GetTurbMagnitude(void) const {return Magnitude;}
+  virtual const FGColumnVector3& GetTurbDirection(void) const {return vDirection;}
+  virtual const FGColumnVector3& GetTurbPQR(void) const {return vTurbPQR;}
 
-  void   SetWindspeed20ft(double ws) { windspeed_at_20ft = ws;}
-  double GetWindspeed20ft() const { return windspeed_at_20ft;}
+  virtual void   SetWindspeed20ft(double ws) { windspeed_at_20ft = ws;}
+  virtual double GetWindspeed20ft() const { return windspeed_at_20ft;}
 
   /// allowable range: 0-7, 3=light, 4=moderate, 6=severe turbulence
-  void   SetProbabilityOfExceedence( int idx) {probability_of_exceedence_index = idx;}
-  int    GetProbabilityOfExceedence() const { return probability_of_exceedence_index;}
+  virtual void   SetProbabilityOfExceedence( int idx) {probability_of_exceedence_index = idx;}
+  virtual int    GetProbabilityOfExceedence() const { return probability_of_exceedence_index;}
 
 protected:
   double rho;
@@ -338,7 +343,7 @@ protected:
   /// Get T, P and rho for a standard atmosphere at the given altitude.
   void GetStdAtmosphere(double altitude);
   void Turbulence(void);
-  void bind(void);
+  virtual void bind(void);
   void Debug(int from);
 };
 
diff --git a/src/FDM/JSBSim/models/FGAuxiliary.cpp b/src/FDM/JSBSim/models/FGAuxiliary.cpp
old mode 100644
new mode 100755
index 36c1e084a..0993bc757
--- a/src/FDM/JSBSim/models/FGAuxiliary.cpp
+++ b/src/FDM/JSBSim/models/FGAuxiliary.cpp
@@ -59,7 +59,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGAuxiliary.cpp,v 1.47 2011/03/29 11:49:27 jberndt Exp $";
+static const char *IdSrc = "$Id: FGAuxiliary.cpp,v 1.49 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_AUXILIARY;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -70,13 +70,14 @@ CLASS IMPLEMENTATION
 FGAuxiliary::FGAuxiliary(FGFDMExec* fdmex) : FGModel(fdmex)
 {
   Name = "FGAuxiliary";
-  vcas = veas = pt = tat = 0;
-  psl = rhosl = 1;
-  qbar = 0;
-  qbarUW = 0.0;
-  qbarUV = 0.0;
-  Re = 0.0;
-  Mach = 0.0;
+  pt = p = psl = 1.0;
+  rho = rhosl = 1.0;
+  tat = sat = 1.0;
+  tatc = RankineToCelsius(tat);
+
+  vcas = veas = 0.0;
+  qbar = qbarUW = qbarUV = 0.0;
+  Mach = MachU = 0.0;
   alpha = beta = 0.0;
   adot = bdot = 0.0;
   gamma = Vt = Vground = 0.0;
@@ -84,13 +85,19 @@ FGAuxiliary::FGAuxiliary(FGFDMExec* fdmex) : FGModel(fdmex)
   day_of_year = 1;
   seconds_in_day = 0.0;
   hoverbmac = hoverbcg = 0.0;
-  tatc = RankineToCelsius(tat);
+  Re = 0.0;
+  Nz = 0.0;
+  lon_relative_position = lat_relative_position = relative_position = 0.0;
 
   vPilotAccel.InitMatrix();
   vPilotAccelN.InitMatrix();
   vToEyePt.InitMatrix();
+  vAeroUVW.InitMatrix();
   vAeroPQR.InitMatrix();
+  vMachUVW.InitMatrix();
+  vEuler.InitMatrix();
   vEulerRates.InitMatrix();
+  vAircraftAccel.InitMatrix();
 
   bind();
 
@@ -101,14 +108,16 @@ FGAuxiliary::FGAuxiliary(FGFDMExec* fdmex) : FGModel(fdmex)
 
 bool FGAuxiliary::InitModel(void)
 {
-  if (!FGModel::InitModel()) return false;
-
-  vcas = veas = pt = tat = 0;
-  psl = rhosl = 1;
-  qbar = 0;
-  qbarUW = 0.0;
-  qbarUV = 0.0;
-  Mach = 0.0;
+  pt = p = FDMExec->GetAtmosphere()->GetPressure();
+  rho = FDMExec->GetAtmosphere()->GetDensity();
+  rhosl = FDMExec->GetAtmosphere()->GetDensitySL();
+  psl = FDMExec->GetAtmosphere()->GetPressureSL();
+  tat = sat = FDMExec->GetAtmosphere()->GetTemperature();
+  tatc = RankineToCelsius(tat);
+
+  vcas = veas = 0.0;
+  qbar = qbarUW = qbarUV = 0.0;
+  Mach = MachU = 0.0;
   alpha = beta = 0.0;
   adot = bdot = 0.0;
   gamma = Vt = Vground = 0.0;
@@ -116,12 +125,19 @@ bool FGAuxiliary::InitModel(void)
   day_of_year = 1;
   seconds_in_day = 0.0;
   hoverbmac = hoverbcg = 0.0;
+  Re = 0.0;
+  Nz = 0.0;
+  lon_relative_position = lat_relative_position = relative_position = 0.0;
 
   vPilotAccel.InitMatrix();
   vPilotAccelN.InitMatrix();
   vToEyePt.InitMatrix();
+  vAeroUVW.InitMatrix();
   vAeroPQR.InitMatrix();
+  vMachUVW.InitMatrix();
+  vEuler.InitMatrix();
   vEulerRates.InitMatrix();
+  vAircraftAccel.InitMatrix();
 
   return true;
 }
@@ -135,12 +151,12 @@ FGAuxiliary::~FGAuxiliary()
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-bool FGAuxiliary::Run()
+bool FGAuxiliary::Run(bool Holding)
 {
   double A,B,D;
 
-  if (FGModel::Run()) return true; // return true if error returned from base class
-  if (FDMExec->Holding()) return false;
+  if (FGModel::Run(Holding)) return true; // return true if error returned from base class
+  if (Holding) return false;
 
   RunPreFunctions();
 
diff --git a/src/FDM/JSBSim/models/FGAuxiliary.h b/src/FDM/JSBSim/models/FGAuxiliary.h
index 8f7821245..3061a8cd6 100644
--- a/src/FDM/JSBSim/models/FGAuxiliary.h
+++ b/src/FDM/JSBSim/models/FGAuxiliary.h
@@ -47,7 +47,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_AUXILIARY "$Id: FGAuxiliary.h,v 1.19 2010/11/18 12:38:06 jberndt Exp $"
+#define ID_AUXILIARY "$Id: FGAuxiliary.h,v 1.20 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -99,7 +99,7 @@ CLASS DOCUMENTATION
     The radius R is calculated below in the vector vToEyePt.
 
     @author Tony Peden, Jon Berndt
-    @version $Id: FGAuxiliary.h,v 1.19 2010/11/18 12:38:06 jberndt Exp $
+    @version $Id: FGAuxiliary.h,v 1.20 2011/05/20 03:18:36 jberndt Exp $
 */
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -118,8 +118,13 @@ public:
   bool InitModel(void);
 
   /** Runs the Auxiliary routines; called by the Executive
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
       @return false if no error */
-  bool Run(void);
+  bool Run(bool Holding);
 
 // GET functions
 
diff --git a/src/FDM/JSBSim/models/FGBuoyantForces.cpp b/src/FDM/JSBSim/models/FGBuoyantForces.cpp
index d12777478..96fd81d67 100644
--- a/src/FDM/JSBSim/models/FGBuoyantForces.cpp
+++ b/src/FDM/JSBSim/models/FGBuoyantForces.cpp
@@ -45,7 +45,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGBuoyantForces.cpp,v 1.16 2011/03/23 11:58:29 jberndt Exp $";
+static const char *IdSrc = "$Id: FGBuoyantForces.cpp,v 1.17 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_BUOYANTFORCES;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -80,17 +80,15 @@ FGBuoyantForces::~FGBuoyantForces()
 
 bool FGBuoyantForces::InitModel(void)
 {
-  if (!FGModel::InitModel()) return false;
-
   return true;
 }
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-bool FGBuoyantForces::Run(void)
+bool FGBuoyantForces::Run(bool Holding)
 {
-  if (FGModel::Run()) return true;
-  if (FDMExec->Holding()) return false; // if paused don't execute
+  if (FGModel::Run(Holding)) return true;
+  if (Holding) return false; // if paused don't execute
   if (NoneDefined) return true;
 
   RunPreFunctions();
diff --git a/src/FDM/JSBSim/models/FGBuoyantForces.h b/src/FDM/JSBSim/models/FGBuoyantForces.h
index c27566d37..e3baab137 100644
--- a/src/FDM/JSBSim/models/FGBuoyantForces.h
+++ b/src/FDM/JSBSim/models/FGBuoyantForces.h
@@ -51,7 +51,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_BUOYANTFORCES "$Id: FGBuoyantForces.h,v 1.11 2010/05/07 20:38:34 andgi Exp $"
+#define ID_BUOYANTFORCES "$Id: FGBuoyantForces.h,v 1.12 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -96,7 +96,7 @@ CLASS DOCUMENTATION
     See FGGasCell for the full configuration file format for gas cells.
 
     @author Anders Gidenstam, Jon S. Berndt
-    @version $Id: FGBuoyantForces.h,v 1.11 2010/05/07 20:38:34 andgi Exp $
+    @version $Id: FGBuoyantForces.h,v 1.12 2011/05/20 03:18:36 jberndt Exp $
 */
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -116,8 +116,13 @@ public:
   bool InitModel(void);
 
   /** Runs the Buoyant forces model; called by the Executive
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
       @return false if no error */
-  bool Run(void);
+  bool Run(bool Holding);
 
   /** Loads the Buoyant forces model.
       The Load function for this class expects the XML parser to
diff --git a/src/FDM/JSBSim/models/FGExternalReactions.cpp b/src/FDM/JSBSim/models/FGExternalReactions.cpp
old mode 100644
new mode 100755
index e39f8fb07..54a219bc4
--- a/src/FDM/JSBSim/models/FGExternalReactions.cpp
+++ b/src/FDM/JSBSim/models/FGExternalReactions.cpp
@@ -53,7 +53,7 @@ DEFINITIONS
 GLOBAL DATA
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-static const char *IdSrc = "$Id: FGExternalReactions.cpp,v 1.9 2010/09/07 00:40:03 jberndt Exp $";
+static const char *IdSrc = "$Id: FGExternalReactions.cpp,v 1.10 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_EXTERNALREACTIONS;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -104,17 +104,15 @@ FGExternalReactions::~FGExternalReactions()
 
 bool FGExternalReactions::InitModel(void)
 {
-  if (!FGModel::InitModel()) return false;
-
   return true;
 }
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-bool FGExternalReactions::Run()
+bool FGExternalReactions::Run(bool Holding)
 {
-  if (FGModel::Run()) return true;
-  if (FDMExec->Holding()) return false; // if paused don't execute
+  if (FGModel::Run(Holding)) return true;
+  if (Holding) return false; // if paused don't execute
   if (NoneDefined) return true;
 
   RunPreFunctions();
diff --git a/src/FDM/JSBSim/models/FGExternalReactions.h b/src/FDM/JSBSim/models/FGExternalReactions.h
old mode 100644
new mode 100755
index 4b7df2d85..36666697f
--- a/src/FDM/JSBSim/models/FGExternalReactions.h
+++ b/src/FDM/JSBSim/models/FGExternalReactions.h
@@ -46,7 +46,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_EXTERNALREACTIONS "$Id: FGExternalReactions.h,v 1.10 2010/11/18 12:38:06 jberndt Exp $"
+#define ID_EXTERNALREACTIONS "$Id: FGExternalReactions.h,v 1.11 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -132,9 +132,13 @@ public:
   bool InitModel(void);
 
   /** Sum all the constituent forces for this cycle.
-      @return true always.
-  */
-  bool Run(void);
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
+      @return true always.  */
+  bool Run(bool Holding);
   
   /** Loads the external forces from the XML configuration file.
       If the external_reactions section is encountered in the vehicle configuration
diff --git a/src/FDM/JSBSim/models/FGFCS.cpp b/src/FDM/JSBSim/models/FGFCS.cpp
index a3b7e91bc..67c02d698 100644
--- a/src/FDM/JSBSim/models/FGFCS.cpp
+++ b/src/FDM/JSBSim/models/FGFCS.cpp
@@ -63,7 +63,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGFCS.cpp,v 1.73 2011/04/05 20:20:21 andgi Exp $";
+static const char *IdSrc = "$Id: FGFCS.cpp,v 1.74 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_FCS;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -123,8 +123,6 @@ bool FGFCS::InitModel(void)
 {
   unsigned int i;
 
-  if (!FGModel::InitModel()) return false;
-
   for (i=0; i<ThrottlePos.size(); i++) ThrottlePos[i] = 0.0;
   for (i=0; i<MixturePos.size(); i++) MixturePos[i] = 0.0;
   for (i=0; i<ThrottleCmd.size(); i++) ThrottleCmd[i] = 0.0;
@@ -191,12 +189,12 @@ bool FGFCS::InitModel(void)
 // actually present in the flight_control or autopilot section will override
 // these simple assignments.
 
-bool FGFCS::Run(void)
+bool FGFCS::Run(bool Holding)
 {
   unsigned int i;
 
-  if (FGModel::Run()) return true; // fast exit if nothing to do
-  if (FDMExec->Holding()) return false;
+  if (FGModel::Run(Holding)) return true; // fast exit if nothing to do
+  if (Holding) return false;
 
   RunPreFunctions();
 
diff --git a/src/FDM/JSBSim/models/FGFCS.h b/src/FDM/JSBSim/models/FGFCS.h
index 6b97297d5..9e6736eed 100644
--- a/src/FDM/JSBSim/models/FGFCS.h
+++ b/src/FDM/JSBSim/models/FGFCS.h
@@ -51,7 +51,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_FCS "$Id: FGFCS.h,v 1.35 2011/04/05 20:20:21 andgi Exp $"
+#define ID_FCS "$Id: FGFCS.h,v 1.36 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -168,7 +168,7 @@ CLASS DOCUMENTATION
     @property gear/tailhook-pos-norm
 
     @author Jon S. Berndt
-    @version $Revision: 1.35 $
+    @version $Revision: 1.36 $
     @see FGActuator
     @see FGDeadBand
     @see FGFCSFunction
@@ -200,8 +200,13 @@ public:
   bool InitModel(void);
 
   /** Runs the Flight Controls model; called by the Executive
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
       @return false if no error */
-  bool Run(void);
+  bool Run(bool Holding);
 
   /// @name Pilot input command retrieval
   //@{
diff --git a/src/FDM/JSBSim/models/FGGroundReactions.cpp b/src/FDM/JSBSim/models/FGGroundReactions.cpp
index 9126c9f81..7f92cec41 100644
--- a/src/FDM/JSBSim/models/FGGroundReactions.cpp
+++ b/src/FDM/JSBSim/models/FGGroundReactions.cpp
@@ -46,7 +46,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGGroundReactions.cpp,v 1.31 2010/11/18 12:38:06 jberndt Exp $";
+static const char *IdSrc = "$Id: FGGroundReactions.cpp,v 1.32 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_GROUNDREACTIONS;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -116,17 +116,15 @@ FGGroundReactions::~FGGroundReactions(void)
 
 bool FGGroundReactions::InitModel(void)
 {
-  if (!FGModel::InitModel()) return false;
-
   return true;
 }
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-bool FGGroundReactions::Run(void)
+bool FGGroundReactions::Run(bool Holding)
 {
-  if (FGModel::Run()) return true;
-  if (FDMExec->Holding()) return false;
+  if (FGModel::Run(Holding)) return true;
+  if (Holding) return false;
 
   RunPreFunctions();
 
diff --git a/src/FDM/JSBSim/models/FGGroundReactions.h b/src/FDM/JSBSim/models/FGGroundReactions.h
index 30792225d..64bfafa1b 100644
--- a/src/FDM/JSBSim/models/FGGroundReactions.h
+++ b/src/FDM/JSBSim/models/FGGroundReactions.h
@@ -45,7 +45,7 @@ INCLUDES
 #include "math/FGColumnVector3.h"
 #include "input_output/FGXMLElement.h"
 
-#define ID_GROUNDREACTIONS "$Id: FGGroundReactions.h,v 1.19 2010/11/18 12:38:06 jberndt Exp $"
+#define ID_GROUNDREACTIONS "$Id: FGGroundReactions.h,v 1.20 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -98,7 +98,14 @@ public:
   ~FGGroundReactions(void);
 
   bool InitModel(void);
-  bool Run(void);
+  /** Runs the Ground Reactions model; called by the Executive
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
+      @return false if no error */
+  bool Run(bool Holding);
   bool Load(Element* el);
   const FGColumnVector3& GetForces(void) const {return vForces;}
   double GetForces(int idx) const {return vForces(idx);}
diff --git a/src/FDM/JSBSim/models/FGInertial.cpp b/src/FDM/JSBSim/models/FGInertial.cpp
index 94aa291c3..93874c120 100644
--- a/src/FDM/JSBSim/models/FGInertial.cpp
+++ b/src/FDM/JSBSim/models/FGInertial.cpp
@@ -45,7 +45,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGInertial.cpp,v 1.20 2010/11/18 12:38:06 jberndt Exp $";
+static const char *IdSrc = "$Id: FGInertial.cpp,v 1.21 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_INERTIAL;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -98,8 +98,6 @@ FGInertial::~FGInertial(void)
 
 bool FGInertial::InitModel(void)
 {
-  if (!FGModel::InitModel()) return false;
-
   earthPosAngle   = 0.0;
 
   return true;
@@ -107,11 +105,11 @@ bool FGInertial::InitModel(void)
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-bool FGInertial::Run(void)
+bool FGInertial::Run(bool Holding)
 {
   // Fast return if we have nothing to do ...
-  if (FGModel::Run()) return true;
-  if (FDMExec->Holding()) return false;
+  if (FGModel::Run(Holding)) return true;
+  if (Holding) return false;
 
   RunPreFunctions();
 
diff --git a/src/FDM/JSBSim/models/FGInertial.h b/src/FDM/JSBSim/models/FGInertial.h
index f4db378a2..5394d81b8 100644
--- a/src/FDM/JSBSim/models/FGInertial.h
+++ b/src/FDM/JSBSim/models/FGInertial.h
@@ -47,7 +47,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_INERTIAL "$Id: FGInertial.h,v 1.15 2010/01/27 04:01:09 jberndt Exp $"
+#define ID_INERTIAL "$Id: FGInertial.h,v 1.16 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -75,7 +75,14 @@ public:
 
   bool InitModel(void);
 
-  bool Run(void);
+  /** Runs the Inertial model; called by the Executive
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
+      @return false if no error */
+  bool Run(bool Holding);
   double SLgravity(void) const {return gAccelReference;}
   double gravity(void) const {return gAccel;}
   double omega(void) const {return RotationRate;}
diff --git a/src/FDM/JSBSim/models/FGInput.cpp b/src/FDM/JSBSim/models/FGInput.cpp
index 51b4a3984..c1ff0b8f2 100755
--- a/src/FDM/JSBSim/models/FGInput.cpp
+++ b/src/FDM/JSBSim/models/FGInput.cpp
@@ -53,7 +53,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGInput.cpp,v 1.20 2010/11/18 12:38:06 jberndt Exp $";
+static const char *IdSrc = "$Id: FGInput.cpp,v 1.21 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_INPUT;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -83,8 +83,6 @@ FGInput::~FGInput()
 
 bool FGInput::InitModel(void)
 {
-  if (!FGModel::InitModel()) return false;
-
   return true;
 }
 
@@ -93,14 +91,14 @@ bool FGInput::InitModel(void)
 // This function handles accepting input commands from the socket interface.
 //
 
-bool FGInput::Run(void)
+bool FGInput::Run(bool Holding)
 {
   string line, token;
   size_t start=0, string_start=0, string_end=0;
   double value=0;
   FGPropertyManager* node=0;
 
-  if (FGModel::Run()) return true; // fast exit if nothing to do
+  if (FGModel::Run(Holding)) return true; // fast exit if nothing to do
   if (port == 0) return false;      // Do nothing here if port not defined
                                     // return false if no error
   // This model DOES execute if "Exec->Holding"
@@ -157,7 +155,7 @@ bool FGInput::Run(void)
           break;
         }
         if (node == 0) {
-          if (FDMExec->Holding()) { // if holding can query property list
+          if (Holding) { // if holding can query property list
             string query = FDMExec->QueryPropertyCatalog(argument);
             socket->Reply(query);
           } else {
diff --git a/src/FDM/JSBSim/models/FGInput.h b/src/FDM/JSBSim/models/FGInput.h
old mode 100644
new mode 100755
index b86a428c6..68f0e0c4a
--- a/src/FDM/JSBSim/models/FGInput.h
+++ b/src/FDM/JSBSim/models/FGInput.h
@@ -46,7 +46,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_INPUT "$Id: FGInput.h,v 1.8 2009/10/24 22:59:30 jberndt Exp $"
+#define ID_INPUT "$Id: FGInput.h,v 1.9 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -76,7 +76,14 @@ public:
   ~FGInput();
 
   bool InitModel(void);
-  bool Run(void);
+  /** Runs the Input model; called by the Executive
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
+      @return false if no error */
+  bool Run(bool Holding);
 
   inline void Enable(void) { enabled = true; }
   inline void Disable(void) { enabled = false; }
diff --git a/src/FDM/JSBSim/models/FGMassBalance.cpp b/src/FDM/JSBSim/models/FGMassBalance.cpp
index fd067ab51..aee3cc3bb 100644
--- a/src/FDM/JSBSim/models/FGMassBalance.cpp
+++ b/src/FDM/JSBSim/models/FGMassBalance.cpp
@@ -51,7 +51,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGMassBalance.cpp,v 1.34 2010/11/18 12:38:06 jberndt Exp $";
+static const char *IdSrc = "$Id: FGMassBalance.cpp,v 1.35 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_MASSBALANCE;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -92,8 +92,6 @@ FGMassBalance::~FGMassBalance()
 
 bool FGMassBalance::InitModel(void)
 {
-  if (!FGModel::InitModel()) return false;
-
   vLastXYZcg.InitMatrix(0.0);
   vDeltaXYZcg.InitMatrix(0.0);
 
@@ -164,13 +162,13 @@ bool FGMassBalance::Load(Element* el)
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-bool FGMassBalance::Run(void)
+bool FGMassBalance::Run(bool Holding)
 {
   double denom, k1, k2, k3, k4, k5, k6;
   double Ixx, Iyy, Izz, Ixy, Ixz, Iyz;
 
-  if (FGModel::Run()) return true;
-  if (FDMExec->Holding()) return false;
+  if (FGModel::Run(Holding)) return true;
+  if (Holding) return false;
 
   RunPreFunctions();
 
diff --git a/src/FDM/JSBSim/models/FGMassBalance.h b/src/FDM/JSBSim/models/FGMassBalance.h
index c7468c5db..53279d39c 100644
--- a/src/FDM/JSBSim/models/FGMassBalance.h
+++ b/src/FDM/JSBSim/models/FGMassBalance.h
@@ -49,7 +49,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_MASSBALANCE "$Id: FGMassBalance.h,v 1.22 2010/11/18 12:38:06 jberndt Exp $"
+#define ID_MASSBALANCE "$Id: FGMassBalance.h,v 1.23 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONSS
@@ -116,7 +116,14 @@ public:
 
   bool Load(Element* el);
   bool InitModel(void);
-  bool Run(void);
+  /** Runs the Mass Balance model; called by the Executive
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
+      @return false if no error */
+  bool Run(bool Holding);
 
   double GetMass(void) const {return Mass;}
   double GetWeight(void) const {return Weight;}
diff --git a/src/FDM/JSBSim/models/FGModel.cpp b/src/FDM/JSBSim/models/FGModel.cpp
index df7ffbdd0..81961eb30 100644
--- a/src/FDM/JSBSim/models/FGModel.cpp
+++ b/src/FDM/JSBSim/models/FGModel.cpp
@@ -38,26 +38,15 @@ HISTORY
 INCLUDES
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
+#include <iostream>
 #include "FGModel.h"
 #include "FGFDMExec.h"
-#include "FGAtmosphere.h"
-#include "FGFCS.h"
-#include "FGPropulsion.h"
-#include "FGMassBalance.h"
-#include "FGAerodynamics.h"
-#include "FGInertial.h"
-#include "FGGroundReactions.h"
-#include "FGExternalReactions.h"
-#include "FGAircraft.h"
-#include "FGPropagate.h"
-#include "FGAuxiliary.h"
-#include <iostream>
 
 using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGModel.cpp,v 1.17 2011/02/16 12:30:53 jberndt Exp $";
+static const char *IdSrc = "$Id: FGModel.cpp,v 1.19 2011/05/22 12:44:30 jberndt Exp $";
 static const char *IdHdr = ID_MODEL;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -99,7 +88,7 @@ bool FGModel::InitModel(void)
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-bool FGModel::Run()
+bool FGModel::Run(bool Holding)
 {
   if (debug_lvl & 4) cout << "Entering Run() for model " << Name << endl;
 
diff --git a/src/FDM/JSBSim/models/FGModel.h b/src/FDM/JSBSim/models/FGModel.h
index 470dc731a..eae604668 100644
--- a/src/FDM/JSBSim/models/FGModel.h
+++ b/src/FDM/JSBSim/models/FGModel.h
@@ -48,7 +48,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_MODEL "$Id: FGModel.h,v 1.18 2010/11/18 12:38:06 jberndt Exp $"
+#define ID_MODEL "$Id: FGModel.h,v 1.19 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -83,10 +83,17 @@ public:
 
   std::string Name;
 
-  /** Runs the model; called by the Executive
+  /** Runs the model; called by the Executive.
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given. The Holding flag is not used in the base
+                     FGModel class.
       @see JSBSim.cpp documentation
       @return false if no error */
-  virtual bool Run(void);
+  virtual bool Run(bool Holding);
+
   virtual bool InitModel(void);
   virtual void SetRate(int tt) {rate = tt;}
   virtual int  GetRate(void)   {return rate;}
diff --git a/src/FDM/JSBSim/models/FGOutput.cpp b/src/FDM/JSBSim/models/FGOutput.cpp
index ab70cb2d2..3131cd6c0 100644
--- a/src/FDM/JSBSim/models/FGOutput.cpp
+++ b/src/FDM/JSBSim/models/FGOutput.cpp
@@ -74,7 +74,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGOutput.cpp,v 1.54 2011/03/11 13:02:26 jberndt Exp $";
+static const char *IdSrc = "$Id: FGOutput.cpp,v 1.55 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_OUTPUT;
 
 // (stolen from FGFS native_fdm.cxx)
@@ -157,8 +157,6 @@ FGOutput::~FGOutput()
 
 bool FGOutput::InitModel(void)
 {
-  if (!FGModel::InitModel()) return false;
-
   if (Filename.size() > 0 && StartNewFile) {
     ostringstream buf;
     string::size_type dot = BaseFilename.find_last_of('.');
@@ -178,11 +176,11 @@ bool FGOutput::InitModel(void)
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-bool FGOutput::Run(void)
+bool FGOutput::Run(bool Holding)
 {
-  if (FGModel::Run()) return true;
+  if (FGModel::Run(Holding)) return true;
 
-  if (enabled && !FDMExec->IntegrationSuspended() && !FDMExec->Holding()) {
+  if (enabled && !FDMExec->IntegrationSuspended() && !Holding) {
     RunPreFunctions();
     Print();
     RunPostFunctions();
diff --git a/src/FDM/JSBSim/models/FGOutput.h b/src/FDM/JSBSim/models/FGOutput.h
index e22dc1319..2640bbdcb 100644
--- a/src/FDM/JSBSim/models/FGOutput.h
+++ b/src/FDM/JSBSim/models/FGOutput.h
@@ -51,7 +51,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_OUTPUT "$Id: FGOutput.h,v 1.22 2011/03/11 13:02:26 jberndt Exp $"
+#define ID_OUTPUT "$Id: FGOutput.h,v 1.23 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -124,7 +124,7 @@ CLASS DOCUMENTATION
     propulsion       ON|OFF
 </pre>
     NOTE that Time is always output with the data.
-    @version $Id: FGOutput.h,v 1.22 2011/03/11 13:02:26 jberndt Exp $
+    @version $Id: FGOutput.h,v 1.23 2011/05/20 03:18:36 jberndt Exp $
  */
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -138,7 +138,14 @@ public:
   ~FGOutput();
 
   bool InitModel(void);
-  bool Run(void);
+  /** Runs the Output model; called by the Executive
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
+      @return false if no error */
+  bool Run(bool Holding);
 
   void Print(void);
   void DelimitedOutput(const std::string&);
diff --git a/src/FDM/JSBSim/models/FGPropagate.cpp b/src/FDM/JSBSim/models/FGPropagate.cpp
index 6202ccc1c..51bc472d2 100644
--- a/src/FDM/JSBSim/models/FGPropagate.cpp
+++ b/src/FDM/JSBSim/models/FGPropagate.cpp
@@ -71,7 +71,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGPropagate.cpp,v 1.86 2011/04/17 11:27:14 bcoconni Exp $";
+static const char *IdSrc = "$Id: FGPropagate.cpp,v 1.88 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_PROPAGATE;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -121,8 +121,6 @@ FGPropagate::~FGPropagate(void)
 
 bool FGPropagate::InitModel(void)
 {
-  if (!FGModel::InitModel()) return false;
-
   // For initialization ONLY:
   SeaLevelRadius = LocalTerrainRadius = FDMExec->GetInertial()->GetRefRadius();
 
@@ -140,10 +138,10 @@ bool FGPropagate::InitModel(void)
   VState.dqInertialVelocity.resize(4, FGColumnVector3(0.0,0.0,0.0));
   VState.dqQtrndot.resize(4, FGColumnVector3(0.0,0.0,0.0));
 
-  integrator_rotational_rate = eAdamsBashforth2;
-  integrator_translational_rate = eTrapezoidal;
-  integrator_rotational_position = eAdamsBashforth2;
-  integrator_translational_position = eTrapezoidal;
+  integrator_rotational_rate = eRectEuler;
+  integrator_translational_rate = eAdamsBashforth2;
+  integrator_rotational_position = eRectEuler;
+  integrator_translational_position = eAdamsBashforth3;
 
   return true;
 }
@@ -226,10 +224,10 @@ Inertial.
 
 */
 
-bool FGPropagate::Run(void)
+bool FGPropagate::Run(bool Holding)
 {
-  if (FGModel::Run()) return true;  // Fast return if we have nothing to do ...
-  if (FDMExec->Holding()) return false;
+  if (FGModel::Run(Holding)) return true;  // Fast return if we have nothing to do ...
+  if (Holding) return false;
 
   double dt = FDMExec->GetDeltaT()*rate;  // The 'stepsize'
 
diff --git a/src/FDM/JSBSim/models/FGPropagate.h b/src/FDM/JSBSim/models/FGPropagate.h
index 26b2ad73e..1afe7f641 100644
--- a/src/FDM/JSBSim/models/FGPropagate.h
+++ b/src/FDM/JSBSim/models/FGPropagate.h
@@ -49,7 +49,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_PROPAGATE "$Id: FGPropagate.h,v 1.58 2011/04/03 19:24:58 jberndt Exp $"
+#define ID_PROPAGATE "$Id: FGPropagate.h,v 1.59 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -102,7 +102,7 @@ CLASS DOCUMENTATION
     @endcode
 
     @author Jon S. Berndt, Mathias Froehlich
-    @version $Id: FGPropagate.h,v 1.58 2011/04/03 19:24:58 jberndt Exp $
+    @version $Id: FGPropagate.h,v 1.59 2011/05/20 03:18:36 jberndt Exp $
   */
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -177,9 +177,14 @@ public:
       other FGModel objects (and others).  */
   bool InitModel(void);
 
-  /** Runs the Propagate model; called by the Executive.
+  /** Runs the state propagation model; called by the Executive
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
       @return false if no error */
-  bool Run(void);
+  bool Run(bool Holding);
 
   const FGQuaternion& GetQuaterniondot(void) const {return vQtrndot;}
 
diff --git a/src/FDM/JSBSim/models/FGPropulsion.cpp b/src/FDM/JSBSim/models/FGPropulsion.cpp
index da82acf51..bb260f09b 100644
--- a/src/FDM/JSBSim/models/FGPropulsion.cpp
+++ b/src/FDM/JSBSim/models/FGPropulsion.cpp
@@ -65,7 +65,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGPropulsion.cpp,v 1.45 2011/02/13 00:42:45 jberndt Exp $";
+static const char *IdSrc = "$Id: FGPropulsion.cpp,v 1.46 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_PROPULSION;
 
 extern short debug_lvl;
@@ -117,8 +117,6 @@ bool FGPropulsion::InitModel(void)
 {
   bool result = true;
 
-  if (!FGModel::InitModel()) return false;
-
   for (unsigned int i=0; i<numTanks; i++) Tanks[i]->ResetToIC();
 
   for (unsigned int i=0; i<numEngines; i++) {
@@ -151,12 +149,12 @@ bool FGPropulsion::InitModel(void)
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-bool FGPropulsion::Run(void)
+bool FGPropulsion::Run(bool Holding)
 {
   unsigned int i;
 
-  if (FGModel::Run()) return true;
-  if (FDMExec->Holding()) return false;
+  if (FGModel::Run(Holding)) return true;
+  if (Holding) return false;
 
   RunPreFunctions();
 
@@ -199,7 +197,7 @@ bool FGPropulsion::GetSteadyState(void)
   vForces.InitMatrix();
   vMoments.InitMatrix();
 
-  if (!FGModel::Run()) {
+  if (!FGModel::Run(false)) {
     FDMExec->SetTrimStatus(true);
 
     for (unsigned int i=0; i<numEngines; i++) {
diff --git a/src/FDM/JSBSim/models/FGPropulsion.h b/src/FDM/JSBSim/models/FGPropulsion.h
index 50dd860cd..3dacfc4fd 100644
--- a/src/FDM/JSBSim/models/FGPropulsion.h
+++ b/src/FDM/JSBSim/models/FGPropulsion.h
@@ -49,7 +49,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_PROPULSION "$Id: FGPropulsion.h,v 1.26 2010/11/18 12:38:06 jberndt Exp $"
+#define ID_PROPULSION "$Id: FGPropulsion.h,v 1.27 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -91,7 +91,7 @@ CLASS DOCUMENTATION
   @endcode
 
     @author Jon S. Berndt
-    @version $Id: FGPropulsion.h,v 1.26 2010/11/18 12:38:06 jberndt Exp $
+    @version $Id: FGPropulsion.h,v 1.27 2011/05/20 03:18:36 jberndt Exp $
     @see
     FGEngine
     FGTank
@@ -112,9 +112,13 @@ public:
   /** Executes the propulsion model.
       The initial plan for the FGPropulsion class calls for Run() to be executed,
       calculating the power available from the engine.
-
-      [Note: Should we be checking the Starved flag here?] */
-  bool Run(void);
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
+      @return false if no error */
+  bool Run(bool Holding);
 
   bool InitModel(void);
 
diff --git a/src/FDM/JSBSim/models/atmosphere/FGMSIS.cpp b/src/FDM/JSBSim/models/atmosphere/FGMSIS.cpp
old mode 100644
new mode 100755
index 0afaa831a..23f185f12
--- a/src/FDM/JSBSim/models/atmosphere/FGMSIS.cpp
+++ b/src/FDM/JSBSim/models/atmosphere/FGMSIS.cpp
@@ -66,7 +66,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGMSIS.cpp,v 1.14 2010/11/18 12:38:06 jberndt Exp $";
+static const char *IdSrc = "$Id: FGMSIS.cpp,v 1.17 2011/05/20 03:18:36 jberndt Exp $";
 static const char *IdHdr = ID_MSIS;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -95,7 +95,19 @@ CLASS IMPLEMENTATION
 MSIS::MSIS(FGFDMExec* fdmex) : FGAtmosphere(fdmex)
 {
   Name = "MSIS";
-  bind();
+
+  for (int i=0; i<9; i++) output.d[i] = 0.0;
+  for (int i=0; i<2; i++) output.t[i] = 0.0;
+
+  dm04 = dm16 = dm28 = dm32 = dm40 = dm01 = dm14 = dfa = 0.0;
+
+  for (int i=0; i<5; i++) meso_tn1[i] = 0.0;
+  for (int i=0; i<4; i++) meso_tn2[i] = 0.0;
+  for (int i=0; i<5; i++) meso_tn3[i] = 0.0;
+  for (int i=0; i<2; i++) meso_tgn1[i] = 0.0;
+  for (int i=0; i<2; i++) meso_tgn2[i] = 0.0;
+  for (int i=0; i<2; i++) meso_tgn3[i] = 0.0;
+
   Debug(0);
 }
 
@@ -110,12 +122,16 @@ MSIS::~MSIS()
 
 bool MSIS::InitModel(void)
 {
-  FGModel::InitModel();
-
   unsigned int i;
 
   flags.switches[0] = 0;
-  for (i=1;i<24;i++) flags.switches[i] = 1;
+  flags.sw[0] = 0;
+  flags.swc[0] = 0;
+  for (i=1;i<24;i++) {
+    flags.switches[i] = 1;
+    flags.sw[i] = 1;
+    flags.swc[i] = 1;
+  }
 
   for (i=0;i<7;i++) aph.a[i] = 100.0;
 
@@ -124,6 +140,8 @@ bool MSIS::InitModel(void)
   input.f107 = 150.0;
   input.ap = 4.0;
 
+  UseInternal();
+
   SLtemperature = intTemperature = 518.0;
   SLpressure    = intPressure = 2116.7;
   SLdensity     = intDensity = 0.002378;
@@ -132,24 +150,21 @@ bool MSIS::InitModel(void)
   rSLpressure    = 1.0/intPressure;
   rSLdensity     = 1.0/intDensity;
   rSLsoundspeed  = 1.0/SLsoundspeed;
-  temperature = &intTemperature;
-  pressure = &intPressure;
-  density = &intDensity;
-
-  UseInternal();
 
   return true;
 }
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-bool MSIS::Run(void)
+bool MSIS::Run(bool Holding)
 {
-  if (FGModel::Run()) return true;
-  if (FDMExec->Holding()) return false;
+  if (FGModel::Run(Holding)) return true;
+  if (Holding) return false;
 
   RunPreFunctions();
 
+  h = FDMExec->GetPropagate()->GetAltitudeASL();
+
   //do temp, pressure, and density first
   if (!useExternal) {
     // get sea-level values
@@ -170,7 +185,7 @@ bool MSIS::Run(void)
     // get at-altitude values
     Calculate(FDMExec->GetAuxiliary()->GetDayOfYear(),
               FDMExec->GetAuxiliary()->GetSecondsInDay(),
-              FDMExec->GetPropagate()->GetAltitudeASL(),
+              h,
               FDMExec->GetPropagate()->GetLocation().GetLatitudeDeg(),
               FDMExec->GetPropagate()->GetLocation().GetLongitudeDeg());
     intTemperature = output.t[1] * 1.8;
@@ -357,7 +372,7 @@ void MSIS::splini (double *xa, double *ya, double *y2a, int n, double x, double
   double yi=0;
   int klo=0;
   int khi=1;
-  double xx, h, a, b, a2, b2;
+  double xx=0.0, h=0.0, a=0.0, b=0.0, a2=0.0, b2=0.0;
   while ((x>xa[klo]) && (khi<n)) {
     xx=x;
     if (khi<(n-1)) {
@@ -472,15 +487,17 @@ double MSIS::densm(double alt, double d0, double xm, double *tz, int mn3,
                      double *tn2, double *tgn2)
 {
 /*      Calculate Temperature and Density Profiles for lower atmos.  */
-  double xs[10], ys[10], y2out[10];
+  double xs[10] = {0,0,0,0,0,0,0,0,0,0};
+  double ys[10] = {0,0,0,0,0,0,0,0,0,0};
+  double y2out[10] = {0,0,0,0,0,0,0,0,0,0};
   double rgas = 831.4;
-  double z, z1, z2, t1, t2, zg, zgdif;
-  double yd1, yd2;
-  double x, y, yi;
-  double expl, gamm, glb;
-  double densm_tmp;
-  int mn;
-  int k;
+  double z=0, z1=0, z2=0, t1=0, t2=0, zg=0, zgdif=0;
+  double yd1=0, yd2=0;
+  double x=0, y=0, yi=0;
+  double expl=0, gamm=0, glb=0;
+  double densm_tmp=0;
+  int mn=0;
+  int k=0;
   densm_tmp=d0;
   if (alt>zn2[0]) {
     if (xm==0.0)
@@ -593,19 +610,19 @@ double MSIS::densu(double alt, double dlb, double tinf, double tlb, double xm,
 /*      Calculate Temperature and Density Profiles for MSIS models
  *      New lower thermo polynomial
  */
-  double yd2, yd1, x=0.0, y=0.0;
+  double yd2=0.0, yd1=0.0, x=0.0, y=0.0;
   double rgas=831.4;
   double densu_temp=1.0;
-  double za, z, zg2, tt, ta=0.0;
-  double dta, z1=0.0, z2, t1=0.0, t2, zg, zgdif=0.0;
+  double za=0.0, z=0.0, zg2=0.0, tt=0.0, ta=0.0;
+  double dta=0.0, z1=0.0, z2=0.0, t1=0.0, t2=0.0, zg=0.0, zgdif=0.0;
   int mn=0;
-  int k;
-  double glb;
-  double expl;
-  double yi;
-  double densa;
-  double gamma, gamm;
-  double xs[5], ys[5], y2out[5];
+  int k=0;
+  double glb=0.0;
+  double expl=0.0;
+  double yi=0.0;
+  double densa=0.0;
+  double gamma=0.0, gamm=0.0;
+  double xs[5]={0.0,0.0,0.0,0.0,0.0}, ys[5]={0.0,0.0,0.0,0.0,0.0}, y2out[5]={0.0,0.0,0.0,0.0,0.0};
   /* joining altitudes of Bates and spline */
   za=zn1[0];
   if (alt>za)
@@ -739,7 +756,7 @@ double MSIS::globe7(double *p, struct nrlmsise_input *input,
   double hr = 0.2618;
   double cd32, cd18, cd14, cd39;
   double p32, p18, p14, p39;
-  double df, dfa;
+  double df;
   double f1, f2;
   double tinf;
   struct ap_array *ap;
@@ -957,11 +974,11 @@ double MSIS::glob7s(double *p, struct nrlmsise_input *input,
 /*    VERSION OF GLOBE FOR LOWER ATMOSPHERE 10/26/99
  */
   double pset=2.0;
-  double t[14];
-  double tt;
-  double cd32, cd18, cd14, cd39;
-  double p32, p18, p14, p39;
-  int i,j;
+  double t[14] = {0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,};
+  double tt=0.0;
+  double cd32=0.0, cd18=0.0, cd14=0.0, cd39=0.0;
+  double p32=0.0, p18=0.0, p14=0.0, p39=0.0;
+  int i=0,j=0;
   double dr=1.72142E-2;
   double dgtr=1.74533E-2;
   /* confirm parameter set */
@@ -1053,23 +1070,26 @@ double MSIS::glob7s(double *p, struct nrlmsise_input *input,
 void MSIS::gtd7(struct nrlmsise_input *input, struct nrlmsise_flags *flags,
                   struct nrlmsise_output *output)
 {
-  double xlat;
-  double xmm;
+  double xlat=0.0;
+  double xmm=0.0;
   int mn3 = 5;
   double zn3[5]={32.5,20.0,15.0,10.0,0.0};
   int mn2 = 4;
   double zn2[4]={72.5,55.0,45.0,32.5};
-  double altt;
+  double altt=0.0;
   double zmix=62.5;
-  double tmp;
-  double dm28m;
-  double tz;
-  double dmc;
-  double dmr;
-  double dz28;
+  double tmp=0.0;
+  double dm28m=0.0;
+  double tz=0.0;
+  double dmc=0.0;
+  double dmr=0.0;
+  double dz28=0.0;
   struct nrlmsise_output soutput;
   int i;
 
+  for (int i=0; i<9; i++) soutput.d[i] = 0.0;
+  for (int i=0; i<2; i++) soutput.t[i] = 0.0;
+
   tselec(flags);
 
   /* Latitude variation of gravity (none for sw[2]=0) */
@@ -1186,6 +1206,8 @@ void MSIS::gtd7d(struct nrlmsise_input *input, struct nrlmsise_flags *flags,
   output->d[5] = 1.66E-24 * (4.0 * output->d[0] + 16.0 * output->d[1] +
                    28.0 * output->d[2] + 32.0 * output->d[3] + 40.0 * output->d[4]
                    + output->d[6] + 14.0 * output->d[7] + 16.0 * output->d[8]);
+  if (flags->sw[0])
+    output->d[5]=output->d[5]/1000;
 }
 
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -1277,36 +1299,36 @@ void MSIS::gts7(struct nrlmsise_input *input, struct nrlmsise_flags *flags,
  *     See GTD7 for more extensive comments
  *     alt > 72.5 km!
  */
-  double za;
+  double za=0.0;
   int i, j;
-  double ddum, z;
+  double ddum=0.0, z=0.0;
   double zn1[5] = {120.0, 110.0, 100.0, 90.0, 72.5};
-  double tinf;
+  double tinf=0.0;
   int mn1 = 5;
-  double g0;
-  double tlb;
-  double s, z0, t0, tr12;
-  double db01, db04, db14, db16, db28, db32, db40, db48;
-  double zh28, zh04, zh16, zh32, zh40, zh01, zh14;
-  double zhm28, zhm04, zhm16, zhm32, zhm40, zhm01, zhm14;
-  double xmd;
-  double b28, b04, b16, b32, b40, b01, b14;
-  double tz;
-  double g28, g4, g16, g32, g40, g1, g14;
-  double zhf, xmm;
-  double zc04, zc16, zc32, zc40, zc01, zc14;
-  double hc04, hc16, hc32, hc40, hc01, hc14;
-  double hcc16, hcc32, hcc01, hcc14;
-  double zcc16, zcc32, zcc01, zcc14;
-  double rc16, rc32, rc01, rc14;
-  double rl;
-  double g16h, db16h, tho, zsht, zmho, zsho;
+  double g0=0.0;
+  double tlb=0.0;
+  double s=0.0, z0=0.0, t0=0.0, tr12=0.0;
+  double db01=0.0, db04=0.0, db14=0.0, db16=0.0, db28=0.0, db32=0.0, db40=0.0, db48=0.0;
+  double zh28=0.0, zh04=0.0, zh16=0.0, zh32=0.0, zh40=0.0, zh01=0.0, zh14=0.0;
+  double zhm28=0.0, zhm04=0.0, zhm16=0.0, zhm32=0.0, zhm40=0.0, zhm01=0.0, zhm14=0.0;
+  double xmd=0.0;
+  double b28=0.0, b04=0.0, b16=0.0, b32=0.0, b40=0.0, b01=0.0, b14=0.0;
+  double tz=0.0;
+  double g28=0.0, g4=0.0, g16=0.0, g32=0.0, g40=0.0, g1=0.0, g14=0.0;
+  double zhf=0.0, xmm=0.0;
+  double zc04=0.0, zc16=0.0, zc32=0.0, zc40=0.0, zc01=0.0, zc14=0.0;
+  double hc04=0.0, hc16=0.0, hc32=0.0, hc40=0.0, hc01=0.0, hc14=0.0;
+  double hcc16=0.0, hcc32=0.0, hcc01=0.0, hcc14=0.0;
+  double zcc16=0.0, zcc32=0.0, zcc01=0.0, zcc14=0.0;
+  double rc16=0.0, rc32=0.0, rc01=0.0, rc14=0.0;
+  double rl=0.0;
+  double g16h=0.0, db16h=0.0, tho=0.0, zsht=0.0, zmho=0.0, zsho=0.0;
   double dgtr=1.74533E-2;
   double dr=1.72142E-2;
   double alpha[9]={-0.38, 0.0, 0.0, 0.0, 0.17, 0.0, -0.38, 0.0, 0.0};
   double altl[8]={200.0, 300.0, 160.0, 250.0, 240.0, 450.0, 320.0, 450.0};
-  double dd;
-  double hc216, hcc232;
+  double dd=0.0;
+  double hc216=0.0, hcc232=0.0;
   za = pdl[1][15];
   zn1[0] = za;
   for (j=0;j<9;j++)
@@ -1480,7 +1502,7 @@ void MSIS::gts7(struct nrlmsise_input *input, struct nrlmsise_flags *flags,
         /**** AR DENSITY ****/
 
         /*   Density variation factor at Zlb */
-  g40= flags->sw[20]*globe7(pd[5],input,flags);
+  g40= flags->sw[21]*globe7(pd[5],input,flags);
         /*  Diffusive density at Zlb */
   db40 = pdm[4][0]*exp(g40)*pd[5][0];
   /*   Diffusive density at Alt */
diff --git a/src/FDM/JSBSim/models/atmosphere/FGMSIS.h b/src/FDM/JSBSim/models/atmosphere/FGMSIS.h
old mode 100644
new mode 100755
index 5761b1921..345a65ad5
--- a/src/FDM/JSBSim/models/atmosphere/FGMSIS.h
+++ b/src/FDM/JSBSim/models/atmosphere/FGMSIS.h
@@ -47,7 +47,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_MSIS "$Id: FGMSIS.h,v 1.7 2010/02/25 05:21:36 jberndt Exp $"
+#define ID_MSIS "$Id: FGMSIS.h,v 1.9 2011/05/20 03:18:36 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -75,7 +75,7 @@ CLASS DOCUMENTATION
     and check http://www.brodo.de/english/pub/nrlmsise/index.html for
     updated releases of this package.
     @author David Culp
-    @version $Id: FGMSIS.h,v 1.7 2010/02/25 05:21:36 jberndt Exp $
+    @version $Id: FGMSIS.h,v 1.9 2011/05/20 03:18:36 jberndt Exp $
 */
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -87,10 +87,60 @@ struct nrlmsise_flags {
   double sw[24];
   double swc[24];
 };
+/*   
+ *   Switches: to turn on and off particular variations use these switches.
+ *   0 is off, 1 is on, and 2 is main effects off but cross terms on.
+ *
+ *   Standard values are 0 for switch 0 and 1 for switches 1 to 23. The 
+ *   array "switches" needs to be set accordingly by the calling program. 
+ *   The arrays sw and swc are set internally.
+ *
+ *   switches[i]:
+ *    i - explanation
+ *   -----------------
+ *    0 - output in centimeters instead of meters
+ *    1 - F10.7 effect on mean
+ *    2 - time independent
+ *    3 - symmetrical annual
+ *    4 - symmetrical semiannual
+ *    5 - asymmetrical annual
+ *    6 - asymmetrical semiannual
+ *    7 - diurnal
+ *    8 - semidiurnal
+ *    9 - daily ap [when this is set to -1 (!) the pointer
+ *                  ap_a in struct nrlmsise_input must
+ *                  point to a struct ap_array]
+ *   10 - all UT/long effects
+ *   11 - longitudinal
+ *   12 - UT and mixed UT/long
+ *   13 - mixed AP/UT/LONG
+ *   14 - terdiurnal
+ *   15 - departures from diffusive equilibrium
+ *   16 - all TINF var
+ *   17 - all TLB var
+ *   18 - all TN1 var
+ *   19 - all S var
+ *   20 - all TN2 var
+ *   21 - all NLB var
+ *   22 - all TN3 var
+ *   23 - turbo scale height var
+ */
 
 struct ap_array {
   double a[7];   
 };
+/* Array containing the following magnetic values:
+ *   0 : daily AP
+ *   1 : 3 hr AP index for current time
+ *   2 : 3 hr AP index for 3 hrs before current time
+ *   3 : 3 hr AP index for 6 hrs before current time
+ *   4 : 3 hr AP index for 9 hrs before current time
+ *   5 : Average of eight 3 hr AP indicies from 12 to 33 hrs 
+ *           prior to current time
+ *   6 : Average of eight 3 hr AP indicies from 36 to 57 hrs 
+ *           prior to current time 
+ */
+
 
 struct nrlmsise_input {
   int year;      /* year, currently ignored                           */
@@ -105,11 +155,71 @@ struct nrlmsise_input {
   double ap;     /* magnetic index(daily)                             */
   struct ap_array *ap_a; /* see above */
 };
+/*
+ *   NOTES ON INPUT VARIABLES: 
+ *      UT, Local Time, and Longitude are used independently in the
+ *      model and are not of equal importance for every situation.  
+ *      For the most physically realistic calculation these three
+ *      variables should be consistent (lst=sec/3600 + g_long/15).
+ *      The Equation of Time departures from the above formula
+ *      for apparent local time can be included if available but
+ *      are of minor importance.
+ *
+ *      f107 and f107A values used to generate the model correspond
+ *      to the 10.7 cm radio flux at the actual distance of the Earth
+ *      from the Sun rather than the radio flux at 1 AU. The following
+ *      site provides both classes of values:
+ *      ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SOLAR_RADIO/FLUX/
+ *
+ *      f107, f107A, and ap effects are neither large nor well
+ *      established below 80 km and these parameters should be set to
+ *      150., 150., and 4. respectively.
+ */
+
+
+
+/* ------------------------------------------------------------------- */
+/* ------------------------------ OUTPUT ----------------------------- */
+/* ------------------------------------------------------------------- */
 
 struct nrlmsise_output {
   double d[9];   /* densities    */
   double t[2];   /* temperatures */
 };
+/* 
+ *   OUTPUT VARIABLES:
+ *      d[0] - HE NUMBER DENSITY(CM-3)
+ *      d[1] - O NUMBER DENSITY(CM-3)
+ *      d[2] - N2 NUMBER DENSITY(CM-3)
+ *      d[3] - O2 NUMBER DENSITY(CM-3)
+ *      d[4] - AR NUMBER DENSITY(CM-3)                       
+ *      d[5] - TOTAL MASS DENSITY(GM/CM3) [includes d[8] in td7d]
+ *      d[6] - H NUMBER DENSITY(CM-3)
+ *      d[7] - N NUMBER DENSITY(CM-3)
+ *      d[8] - Anomalous oxygen NUMBER DENSITY(CM-3)
+ *      t[0] - EXOSPHERIC TEMPERATURE
+ *      t[1] - TEMPERATURE AT ALT
+ * 
+ *
+ *      O, H, and N are set to zero below 72.5 km
+ *
+ *      t[0], Exospheric temperature, is set to global average for
+ *      altitudes below 120 km. The 120 km gradient is left at global
+ *      average value for altitudes below 72 km.
+ *
+ *      d[5], TOTAL MASS DENSITY, is NOT the same for subroutines GTD7 
+ *      and GTD7D
+ *
+ *        SUBROUTINE GTD7 -- d[5] is the sum of the mass densities of the
+ *        species labeled by indices 0-4 and 6-7 in output variable d.
+ *        This includes He, O, N2, O2, Ar, H, and N but does NOT include
+ *        anomalous oxygen (species index 8).
+ *
+ *        SUBROUTINE GTD7D -- d[5] is the "effective total mass density
+ *        for drag" and is the sum of the mass densities of all species
+ *        in this model, INCLUDING anomalous oxygen.
+ */
+
 
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -125,8 +235,13 @@ public:
   /// Destructor
   ~MSIS();
   /** Runs the MSIS-00 atmosphere model; called by the Executive
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
       @return false if no error */
-  bool Run(void);
+  bool Run(bool Holding);
 
   bool InitModel(void);
 
@@ -196,9 +311,25 @@ private:
   double sg0(double ex, double *p, double *ap);
   double globe7(double *p, nrlmsise_input *input, nrlmsise_flags *flags);
   double glob7s(double *p, nrlmsise_input *input, nrlmsise_flags *flags);
+
+// GTD7
+// Neutral Atmosphere Empirical Model from the surface to lower exosphere.
   void gtd7(nrlmsise_input *input, nrlmsise_flags *flags, nrlmsise_output *output);
+
+// GTD7D 
+// This subroutine provides Effective Total Mass Density for output
+// d[5] which includes contributions from "anomalous oxygen" which can
+// affect satellite drag above 500 km. See the section "output" for
+// additional details.
   void gtd7d(nrlmsise_input *input, nrlmsise_flags *flags, nrlmsise_output *output); 
+
+// GHP7
+// To specify outputs at a pressure level (press) rather than at
+// an altitude.
   void ghp7(nrlmsise_input *input, nrlmsise_flags *flags, nrlmsise_output *output, double press);
+
+// GTS7
+// Thermospheric portion of NRLMSISE-00
   void gts7(nrlmsise_input *input, nrlmsise_flags *flags, nrlmsise_output *output); 
 
 };
diff --git a/src/FDM/JSBSim/models/atmosphere/FGStandardAtmosphere.cpp b/src/FDM/JSBSim/models/atmosphere/FGStandardAtmosphere.cpp
new file mode 100644
index 000000000..ab0011c7f
--- /dev/null
+++ b/src/FDM/JSBSim/models/atmosphere/FGStandardAtmosphere.cpp
@@ -0,0 +1,568 @@
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+ Module:       FGStandardAtmosphere.cpp
+ Author:       Jon Berndt, Tony Peden
+ Date started: 5/2011
+ Purpose:      Models the 1976 U.S. Standard Atmosphere
+ Called by:    FGFDMExec
+
+ ------------- Copyright (C) 2011  Jon S. Berndt (jon@jsbsim.org) -------------
+
+ This program is free software; you can redistribute it and/or modify it under
+ the terms of the GNU Lesser General Public License as published by the Free Software
+ Foundation; either version 2 of the License, or (at your option) any later
+ version.
+
+ This program is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+ details.
+
+ You should have received a copy of the GNU Lesser General Public License along with
+ this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ Place - Suite 330, Boston, MA  02111-1307, USA.
+
+ Further information about the GNU Lesser General Public License can also be found on
+ the world wide web at http://www.gnu.org.
+
+FUNCTIONAL DESCRIPTION
+--------------------------------------------------------------------------------
+
+
+HISTORY
+--------------------------------------------------------------------------------
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+COMMENTS, REFERENCES,  and NOTES
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+[1]   Anderson, John D. "Introduction to Flight, Third Edition", McGraw-Hill,
+      1989, ISBN 0-07-001641-0
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+INCLUDES
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
+
+#include <iostream>
+#include <iomanip>
+#include <cstdlib>
+#include "FGFDMExec.h"
+#include "FGStandardAtmosphere.h"
+
+namespace JSBSim {
+
+static const char *IdSrc = "$Id: FGStandardAtmosphere.cpp,v 1.9 2011/06/13 12:06:29 jberndt Exp $";
+static const char *IdHdr = ID_STANDARDATMOSPHERE;
+
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+CLASS IMPLEMENTATION
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
+
+FGStandardAtmosphere::FGStandardAtmosphere(FGFDMExec* fdmex) : FGModel(fdmex),
+                                                               TemperatureDeltaGradient(0.0),
+                                                               TemperatureBias(0.0),
+                                                               PressureAltitude(0.0),      // ft
+                                                               DensityAltitude(0.0),       // ft
+                                                               SutherlandConstant(198.72), // deg Rankine
+                                                               Beta(2.269690E-08)          // slug/(sec ft R^0.5)
+{
+  Name = "FGStandardAtmosphere";
+
+  StdAtmosTemperatureTable = new FGTable(9);
+
+  // This is the U.S. Standard Atmosphere table for temperature in degrees
+  // Rankine, based on geometric altitude. The table values are often given
+  // in literature relative to geopotential altitude. 
+  //
+  //                        GeoMet Alt    Temp      GeoPot Alt  GeoMet Alt
+  //                           (ft)      (deg R)      (km)        (km)
+  //                         --------   --------    ----------  ----------
+  *StdAtmosTemperatureTable <<      0.0 << 518.67 //    0.000       0.000
+                            <<  36151.6 << 390.0  //   11.000      11.019
+                            <<  65823.5 << 390.0  //   20.000      20.063
+                            << 105518.4 << 411.6  //   32.000      32.162
+                            << 155347.8 << 487.2  //   47.000      47.350
+                            << 168677.8 << 487.2  //   51.000      51.413
+                            << 235570.9 << 386.4  //   71.000      71.802
+                            << 282152.2 << 336.5  //   84.852      86.000
+                            << 298556.4 << 336.5; //               91.000 - First layer in high altitude regime 
+
+  LapseRateVector.resize(StdAtmosTemperatureTable->GetNumRows()-1);
+  PressureBreakpointVector.resize(StdAtmosTemperatureTable->GetNumRows());
+
+  // Assume the altitude to fade out the gradient at is at the highest
+  // altitude in the table. Above that, other functions are used to
+  // calculate temperature.
+  GradientFadeoutAltitude = (*StdAtmosTemperatureTable)(StdAtmosTemperatureTable->GetNumRows(),0);
+
+  bind();
+  Debug(0);
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+FGStandardAtmosphere::~FGStandardAtmosphere()
+{
+  LapseRateVector.clear();
+  Debug(1);
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+bool FGStandardAtmosphere::InitModel(void)
+{
+  PressureBreakpointVector[0] = StdSLpressure = 2116.22; // psf
+  TemperatureDeltaGradient = 0.0;
+  TemperatureBias = 0.0;
+  CalculateLapseRates();
+  CalculatePressureBreakpoints();
+  Calculate(0.0);
+  StdSLtemperature = SLtemperature = Temperature;
+  SLpressure = Pressure;
+  StdSLdensity     = SLdensity = Density;
+  StdSLsoundspeed  = SLsoundspeed = Soundspeed;
+
+  rSLtemperature = 1/SLtemperature ;
+  rSLpressure    = 1/SLpressure    ;
+  rSLdensity     = 1/SLdensity     ;
+  rSLsoundspeed  = 1/SLsoundspeed  ;
+
+//  PrintStandardAtmosphereTable();
+
+  return true;
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+bool FGStandardAtmosphere::Run(bool Holding)
+{
+  if (FGModel::Run(Holding)) return true;
+  if (Holding) return false;
+
+  RunPreFunctions();
+
+  double altitude = FDMExec->GetPropagate()->GetAltitudeASL();
+
+  Calculate(altitude);
+
+  RunPostFunctions();
+
+  Debug(2);
+  return false;
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+void FGStandardAtmosphere::Calculate(double altitude)
+{
+  Temperature = GetTemperature(altitude);
+  Pressure = GetPressure(altitude);
+  Density     = Pressure/(Reng*Temperature);
+  Soundspeed  = sqrt(SHRatio*Reng*(Temperature));
+
+  Viscosity = Beta * pow(Temperature, 1.5) / (SutherlandConstant + Temperature);
+  KinematicViscosity = Viscosity / Density;
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+// Get the actual pressure as modeled at a specified altitude
+// These calculations are from equations 33a and 33b in the U.S. Standard Atmosphere
+// document referenced in the documentation for this code.
+
+double FGStandardAtmosphere::GetPressure(double altitude) const
+{
+  unsigned int b=0;
+  double pressure = 0.0;
+  double Lmb, Exp, Tmb, deltaH, factor;
+
+  // Iterate through the altitudes to find the current Base Altitude
+  // in the table. That is, if the current altitude (the argument passed in)
+  // is 20000 ft, then the base altitude from the table is 0.0. If the
+  // passed-in altitude is 40000 ft, the base altitude is 36151.6 ft (and
+  // the index "b" is 2 - the second entry in the table).
+  double testAlt = (*StdAtmosTemperatureTable)(b+1,0);
+  while (altitude >= testAlt) {
+    b++;
+    if (b+1 > StdAtmosTemperatureTable->GetNumRows()) break;
+    testAlt = (*StdAtmosTemperatureTable)(b+1,0);
+  }
+  if (b>0) b--;
+
+  double BaseAlt = (*StdAtmosTemperatureTable)(b+1,0);
+  Tmb = GetTemperature(BaseAlt);
+  deltaH = altitude - BaseAlt;
+
+  if (LapseRateVector[b] != 0.00) {
+    Lmb = LapseRateVector[b];
+    Exp = Mair/(Rstar*Lmb);
+    factor = Tmb/(Tmb + Lmb*deltaH);
+    pressure = PressureBreakpointVector[b]*pow(factor, Exp);
+  } else {
+    pressure = PressureBreakpointVector[b]*exp(-Mair*deltaH/(Rstar*Tmb));
+  }
+
+  return pressure;
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+void FGStandardAtmosphere::SetSeaLevelPressure(double pressure, ePressure unit)
+{
+  double press = ConvertToPSF(pressure, unit);
+
+  PressureBreakpointVector[0] = press;
+  CalculatePressureBreakpoints();
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+// Get the modeled temperature at a specified altitude, including any bias or gradient
+// effects.
+
+double FGStandardAtmosphere::GetTemperature(double altitude) const
+{
+  double T = StdAtmosTemperatureTable->GetValue(altitude) + TemperatureBias;
+  if (altitude <= GradientFadeoutAltitude)
+    T += TemperatureDeltaGradient * (GradientFadeoutAltitude - altitude);
+
+  return T;
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+// Retrieves the standard temperature at a particular altitude.
+
+double FGStandardAtmosphere::GetStdTemperature(double altitude) const
+{
+  double Lk9 = 0.00658368; // deg R per foot
+  double Tinf = 1800.0; // Same as 1000 Kelvin
+  double temp = Tinf;
+
+  if (altitude < 298556.4) {                // 91 km - station 8
+
+    temp = StdAtmosTemperatureTable->GetValue(altitude);
+
+  } else if (altitude < 360892.4) {        // 110 km - station 9
+
+    temp = 473.7429 - 137.38176 * sqrt(1.0 - pow((altitude - 298556.4)/65429.462, 2.0));
+
+  } else if (altitude < 393700.8) {        // 120 km - station 10
+
+    temp = 432 + Lk9 * (altitude - 360892.4);
+
+  } else if (altitude < 3280839.9) {        // 1000 km station 12
+
+    double lambda = 0.00001870364;
+    double eps = (altitude - 393700.8) * (20855531.5 + 393700.8) / (20855531.5 + altitude);
+    temp = Tinf - (Tinf - 648.0) * exp(-lambda*eps);
+
+  }
+
+  return temp;
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+double FGStandardAtmosphere::GetStdPressure(double altitude) const
+{
+  double press=0;
+  if (TemperatureBias == 0.0 && TemperatureDeltaGradient == 0.0 && PressureBreakpointVector[0] == StdSLpressure) {
+    press = GetPressure(altitude);
+  } else if (altitude <= 100000.0) {
+    GetStdPressure100K(altitude);
+  } else {
+    // Cannot currently retrieve the standard pressure
+  }
+  return press;
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+// This function calculates an approximation of the standard atmospheric pressure
+// up to an altitude of about 100,000 ft. If the temperature and pressure are not
+// altered for local conditions, the GetPressure(h) function should be used,
+// as that is valid to a much higher altitude. This function is accurate to within
+// a couple of psf up to 100K ft. This polynomial fit was determined using Excel.
+
+double FGStandardAtmosphere::GetStdPressure100K(double altitude) const
+{
+  // Limit this equation to input altitudes of 100000 ft.
+  if (altitude > 100000.0) altitude = 100000.0;
+
+  double alt[6];
+  double coef[6] = { 2116.22,
+                    -7.583514352598E-02,
+                     1.045494405501E-06,
+                    -5.881341527124E-12,
+                     3.482031690718E-18,
+                     5.683922549284E-23 };
+
+  alt[0] = 1;
+  for (int pwr=1; pwr<=5; pwr++) alt[pwr] = alt[pwr-1]*altitude;
+
+  double press = 0.0;
+  for (int ctr=0; ctr<=5; ctr++) press += coef[ctr]*alt[ctr];
+  return press;
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+// Get the modeled density at a specified altitude
+
+double FGStandardAtmosphere::GetDensity(double altitude) const
+{
+  return GetPressure(altitude)/(Reng * GetTemperature(altitude));
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+// Get the standard density at a specified altitude
+
+double FGStandardAtmosphere::GetStdDensity(double altitude) const
+{
+  return GetStdPressure(altitude)/(Reng * GetStdTemperature(altitude));
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+void FGStandardAtmosphere::SetTemperatureBias(double t, eTemperature unit)
+{
+  TemperatureBias = ConvertToRankine(t, unit);
+  CalculatePressureBreakpoints();
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+// This function calculates a bias based on the supplied temperature for sea
+// level. The bias is applied to the entire temperature profile at all altitudes.
+// Internally, the Rankine scale is used for calculations, so any temperature
+// supplied must be converted to that unit.
+
+void FGStandardAtmosphere::SetSLTemperature(double t, eTemperature unit)
+{
+  double targetSLtemp = ConvertToRankine(t, unit);
+
+  TemperatureBias = targetSLtemp - GetStdTemperatureSL();
+  CalculatePressureBreakpoints();
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+// Sets a Sea Level temperature delta that is ramped out by 86 km (282,152 ft).
+
+void FGStandardAtmosphere::SetSLTemperatureGradedDelta(double deltemp, eTemperature unit)
+{
+  SetTemperatureGradedDelta(deltemp, 0.0, unit);
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+// Sets a temperature delta at the supplied altitude that is ramped out by 86 km.
+// After this calculation is performed, the lapse rates and pressure breakpoints
+// must be recalculated. Since we are calculating a delta here and not an actual
+// temperature, we only need to be concerned about a scale factor and not
+// the actual temperature itself.
+
+void FGStandardAtmosphere::SetTemperatureGradedDelta(double deltemp, double h, eTemperature unit)
+{
+  switch(unit) {
+  case eCelsius:
+  case eKelvin:
+    deltemp *= 9.0/5.0; // If temp delta is given in metric, scale up to English
+    break;
+  }
+  TemperatureDeltaGradient = deltemp/(GradientFadeoutAltitude - h);
+  CalculateLapseRates();
+  CalculatePressureBreakpoints();
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+  void FGStandardAtmosphere::PrintStandardAtmosphereTable()
+{
+  std::cout << "Altitude (ft)   Temp (F)   Pressure (psf)   Density (sl/ft3)" << std::endl;
+  std::cout << "-------------   --------   --------------   ----------------" << std::endl;
+  for (int i=0; i<280000; i+=1000) {
+    Calculate(i);
+    std::cout  << std::setw(12) << std::setprecision(2) << i
+       << "  " << std::setw(9)  << std::setprecision(2) << Temperature-459.67
+       << "  " << std::setw(13) << std::setprecision(4) << Pressure
+       << "  " << std::setw(18) << std::setprecision(8) << Density
+       << std::endl;
+  }
+
+  // Re-execute the Run() method to reset the calculated values
+  Run(false);
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+// This function calculates (or recalculates) the lapse rate over an altitude range
+// where the "bh" in this case refers to the index of the base height in the 
+// StdAtmosTemperatureTable table. This function should be called anytime the 
+// temperature table is altered, such as when a gradient is applied across the 
+// temperature table for a range of altitudes.
+
+void FGStandardAtmosphere::CalculateLapseRates()
+{
+  for (unsigned int bh=0; bh<LapseRateVector.size(); bh++)
+  {
+    double t0 = (*StdAtmosTemperatureTable)(bh+1,1);
+    double t1 = (*StdAtmosTemperatureTable)(bh+2,1);
+    double h0 = (*StdAtmosTemperatureTable)(bh+1,0);
+    double h1 = (*StdAtmosTemperatureTable)(bh+2,0);
+    LapseRateVector[bh] = (t1 - t0) / (h1 - h0) + TemperatureDeltaGradient;
+  }
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+void FGStandardAtmosphere::CalculatePressureBreakpoints()
+{
+  for (unsigned int b=0; b<PressureBreakpointVector.size()-1; b++) {
+    double BaseTemp = (*StdAtmosTemperatureTable)(b+1,1);
+    double BaseAlt = (*StdAtmosTemperatureTable)(b+1,0);
+    double UpperAlt = (*StdAtmosTemperatureTable)(b+2,0);
+    double deltaH = UpperAlt - BaseAlt;
+    double Tmb = BaseTemp
+                 + TemperatureBias 
+                 + (GradientFadeoutAltitude - BaseAlt)*TemperatureDeltaGradient;
+    if (LapseRateVector[b] != 0.00) {
+      double Lmb = LapseRateVector[b];
+      double Exp = Mair/(Rstar*Lmb);
+      double factor = Tmb/(Tmb + Lmb*deltaH);
+      PressureBreakpointVector[b+1] = PressureBreakpointVector[b]*pow(factor, Exp);
+    } else {
+      PressureBreakpointVector[b+1] = PressureBreakpointVector[b]*exp(-Mair*deltaH/(Rstar*Tmb));
+    }
+  }
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+void FGStandardAtmosphere::ResetSLTemperature()
+{
+  TemperatureBias = TemperatureDeltaGradient = 0.0;
+  CalculateLapseRates();
+  CalculatePressureBreakpoints();
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+void FGStandardAtmosphere::ResetSLPressure()
+{
+  PressureBreakpointVector[0] = StdSLpressure; // psf
+  CalculatePressureBreakpoints();
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+double FGStandardAtmosphere::ConvertToRankine(double t, eTemperature unit) const
+{
+  double targetTemp=0; // in degrees Rankine
+
+  switch(unit) {
+  case eFahrenheit:
+    targetTemp = t + 459.67;
+    break;
+  case eCelsius:
+    targetTemp = t*9.0/5.0 + 32.0 + 459.67;
+    break;
+  case eRankine:
+    targetTemp = t;
+    break;
+  case eKelvin:
+    targetTemp = t*9.0/5.0;
+  }
+
+  return targetTemp;
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+double FGStandardAtmosphere::ConvertToPSF(double p, ePressure unit) const
+{
+  double targetPressure=0; // Pressure in PSF
+
+  switch(unit) {
+  case ePSF:
+    targetPressure = p;
+    break;
+  case eMillibars:
+    targetPressure = p*2.08854342;
+    break;
+  case ePascals:
+    targetPressure = p*0.0208854342;
+    break;
+  case eInchesHg:
+    targetPressure = p*70.7180803;
+    break;
+  default:
+    throw("Undefined pressure unit given");
+  }
+
+  return targetPressure;
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+void FGStandardAtmosphere::bind(void)
+{
+  typedef double (FGStandardAtmosphere::*PMFi)(int) const;
+  typedef void (FGStandardAtmosphere::*PMF)(int, double);
+  PropertyManager->Tie("stdatmosphere/T-R", this, &FGStandardAtmosphere::GetTemperature);
+  PropertyManager->Tie("stdatmosphere/rho-slugs_ft3", this, &FGStandardAtmosphere::GetDensity);
+  PropertyManager->Tie("stdatmosphere/P-psf", this, &FGStandardAtmosphere::GetPressure);
+  PropertyManager->Tie("stdatmosphere/a-fps", this, &FGStandardAtmosphere::GetSoundSpeed);
+  PropertyManager->Tie("stdatmosphere/T-sl-R", this, &FGStandardAtmosphere::GetTemperatureSL);
+  PropertyManager->Tie("stdatmosphere/rho-sl-slugs_ft3", this, &FGStandardAtmosphere::GetDensitySL);
+  PropertyManager->Tie("stdatmosphere/P-sl-psf", this, &FGStandardAtmosphere::GetPressureSL);
+  PropertyManager->Tie("stdatmosphere/a-sl-fps", this, &FGStandardAtmosphere::GetSoundSpeedSL);
+  PropertyManager->Tie("stdatmosphere/theta", this, &FGStandardAtmosphere::GetTemperatureRatio);
+  PropertyManager->Tie("stdatmosphere/sigma", this, &FGStandardAtmosphere::GetDensityRatio);
+  PropertyManager->Tie("stdatmosphere/delta", this, &FGStandardAtmosphere::GetPressureRatio);
+  PropertyManager->Tie("stdatmosphere/a-ratio", this, &FGStandardAtmosphere::GetSoundSpeedRatio);
+  PropertyManager->Tie("stdatmosphere/delta-T", this, eRankine,
+                                    (PMFi)&FGStandardAtmosphere::GetTemperatureBias,
+                                    (PMF)&FGStandardAtmosphere::SetTemperatureBias);
+//  PropertyManager->Tie("atmosphere/density-altitude", this, &FGStandardAtmosphere::GetDensityAltitude);
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+//    The bitmasked value choices are as follows:
+//    unset: In this case (the default) JSBSim would only print
+//       out the normally expected messages, essentially echoing
+//       the config files as they are read. If the environment
+//       variable is not set, debug_lvl is set to 1 internally
+//    0: This requests JSBSim not to output any messages
+//       whatsoever.
+//    1: This value explicity requests the normal JSBSim
+//       startup messages
+//    2: This value asks for a message to be printed out when
+//       a class is instantiated
+//    4: When this value is set, a message is displayed when a
+//       FGModel object executes its Run() method
+//    8: When this value is set, various runtime state variables
+//       are printed out periodically
+//    16: When set various parameters are sanity checked and
+//       a message is printed out when they go out of bounds
+
+void FGStandardAtmosphere::Debug(int from)
+{
+  if (debug_lvl <= 0) return;
+
+  if (debug_lvl & 1) { // Standard console startup message output
+    if (from == 0) { // Constructor
+    }
+  }
+  if (debug_lvl & 2 ) { // Instantiation/Destruction notification
+    if (from == 0) std::cout << "Instantiated: FGStandardAtmosphere" << std::endl;
+    if (from == 1) std::cout << "Destroyed:    FGStandardAtmosphere" << std::endl;
+  }
+  if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
+  }
+  if (debug_lvl & 8 ) { // Runtime state variables
+  }
+  if (debug_lvl & 16) { // Sanity checking
+  }
+  if (debug_lvl & 128) { // 
+  }
+  if (debug_lvl & 64) {
+    if (from == 0) { // Constructor
+      std::cout << IdSrc << std::endl;
+      std::cout << IdHdr << std::endl;
+    }
+  }
+}
+
+} // namespace JSBSim
diff --git a/src/FDM/JSBSim/models/atmosphere/FGStandardAtmosphere.h b/src/FDM/JSBSim/models/atmosphere/FGStandardAtmosphere.h
new file mode 100644
index 000000000..07978941e
--- /dev/null
+++ b/src/FDM/JSBSim/models/atmosphere/FGStandardAtmosphere.h
@@ -0,0 +1,379 @@
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+ Header:       FGStandardAtmosphere.h
+ Author:       Jon Berndt
+ Date started: 5/2011
+
+ ------------- Copyright (C) 2011  Jon S. Berndt (jon@jsbsim.org) -------------
+
+ This program is free software; you can redistribute it and/or modify it under
+ the terms of the GNU Lesser General Public License as published by the Free Software
+ Foundation; either version 2 of the License, or (at your option) any later
+ version.
+
+ This program is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+ details.
+
+ You should have received a copy of the GNU Lesser General Public License along with
+ this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ Place - Suite 330, Boston, MA  02111-1307, USA.
+
+ Further information about the GNU Lesser General Public License can also be found on
+ the world wide web at http://www.gnu.org.
+
+HISTORY
+--------------------------------------------------------------------------------
+5/2011   JSB   Created
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+SENTRY
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
+
+#ifndef FGSTANDARDATMOSPHERE_H
+#define FGSTANDARDATMOSPHERE_H
+
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+INCLUDES
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
+
+#include <vector>
+#include "models/FGModel.h"
+#include "math/FGTable.h"
+
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+DEFINITIONS
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
+
+#define ID_STANDARDATMOSPHERE "$Id: FGStandardAtmosphere.h,v 1.9 2011/06/13 12:06:21 jberndt Exp $"
+
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+FORWARD DECLARATIONS
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
+
+namespace JSBSim {
+
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+CLASS DOCUMENTATION
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
+
+/** Models the 1976 U.S. Standard Atmosphere, with the ability to modify the 
+    temperature and pressure. A base feature of the model is the temperature 
+    profile that is stored as an FGTable object with this data:
+
+@code
+GeoMet Alt    Temp      GeoPot Alt  GeoMet Alt
+   (ft)      (deg R)      (km)        (km)
+ ---------  --------    ----------  ----------
+       0.0    518.67 //    0.000       0.000
+   36151.6    390.0  //   11.000      11.019
+   65823.5    390.0  //   20.000      20.063
+  105518.4    411.6  //   32.000      32.162
+  155347.8    487.2  //   47.000      47.350
+  168677.8    487.2  //   51.000      51.413
+  235570.9    386.4  //   71.000      71.802
+  282152.2    336.5; //   84.852      86.000
+@endcode
+
+The pressure is calculated at lower altitudes through the use of two equations
+that are presented in the U.S. Standard Atmosphere document (see references).
+Density, kinematic viscosity, speed of sound, etc., are all calculated based
+on various constants and temperature and pressure. At higher altitudes (above 
+86 km (282152 ft) a different and more complicated method of calculating
+pressure is used.
+The temperature may be modified through the use of several methods. Ultimately,
+these access methods allow the user to modify the sea level standard temperature,
+and/or the sea level standard pressure, so that the entire profile will be 
+consistently and accurately calculated.
+
+  <h2> Properties </h2>
+  @property atmosphere/T-R The current modeled temperature in degrees Rankine.
+  @property atmosphere/rho-slugs_ft3
+  @property atmosphere/P-psf
+  @property atmosphere/a-fps
+  @property atmosphere/T-sl-R
+  @property atmosphere/rho-sl-slugs_ft3
+  @property atmosphere/P-sl-psf
+  @property atmosphere/a-sl-fps
+  @property atmosphere/theta
+  @property atmosphere/sigma
+  @property atmosphere/delta
+  @property atmosphere/a-ratio
+  @property atmosphere/delta-T
+  @property atmosphere/T-sl-dev-F
+
+  @author Jon Berndt
+  @see "U.S. Standard Atmosphere, 1976", NASA TM-X-74335
+  @version $Id: FGStandardAtmosphere.h,v 1.9 2011/06/13 12:06:21 jberndt Exp $
+*/
+
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+CLASS DECLARATION
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
+
+class FGStandardAtmosphere : public FGModel {
+public:
+
+  /// Enums for specifying temperature units.
+  enum eTemperature {eNoTempUnit=0, eFahrenheit, eCelsius, eRankine, eKelvin};
+
+  /// Enums for specifying pressure units.
+  enum ePressure {eNoPressUnit=0, ePSF, eMillibars, ePascals, eInchesHg};
+
+  /// Constructor
+  FGStandardAtmosphere(FGFDMExec*);
+  /// Destructor
+  ~FGStandardAtmosphere();
+  /** Runs the standard atmosphere forces model; called by the Executive.
+      Can pass in a value indicating if the executive is directing the simulation to Hold.
+      @param Holding if true, the executive has been directed to hold the sim from 
+                     advancing time. Some models may ignore this flag, such as the Input
+                     model, which may need to be active to listen on a socket for the
+                     "Resume" command to be given.
+      @return false if no error */
+  bool Run(bool Holding);
+  bool InitModel(void);
+
+  //  *************************************************************************
+  /// @name Temperature access functions.
+  /// There are several ways to get the temperature, and several modeled temperature
+  /// values that can be retrieved. The U.S. Standard Atmosphere temperature either
+  /// at a specified altitude, or at sea level can be retrieved. These two temperatures
+  /// do NOT include the effects of any bias or delta gradient that may have been
+  /// supplied by the user. The modeled temperature and the modeled temperature
+  /// at sea level can also be retrieved. These two temperatures DO include the
+  /// effects of an optionally user-supplied bias or delta gradient.
+  // @{
+  /// Returns the actual, modeled temperature at the current altitude in degrees Rankine.
+  /// @return Modeled temperature in degrees Rankine.
+  virtual double GetTemperature() const {return Temperature;}
+
+  /// Returns the actual modeled temperature in degrees Rankine at a specified altitude.
+  /// @param altitude The altitude above sea level (ASL) in feet.
+  /// @return Modeled temperature in degrees Rankine at the specified altitude.
+  virtual double GetTemperature(double altitude) const;
+
+  /// Returns the actual, modeled sea level temperature in degrees Rankine.
+  /// @return The modeled temperature in degrees Rankine at sea level.
+  virtual double GetTemperatureSL() const { return GetTemperature(0.0); }
+
+  /// Returns the standard temperature in degrees Rankine at a specified altitude.
+  /// @param altitude The altitude in feet above sea level (ASL) to get the temperature at.
+  /// @return The STANDARD temperature in degrees Rankine at the specified altitude.
+  virtual double GetStdTemperature(double altitude) const;
+
+  /// Returns the standard sea level temperature in degrees Rankine.
+  /// @return The STANDARD temperature at sea level in degrees Rankine.
+  virtual double GetStdTemperatureSL() const { return GetStdTemperature(0.0); }
+
+  /// Returns the ratio of the at-current-altitude temperature as modeled
+  /// over the standard sea level value.
+  virtual double GetTemperatureRatio() const { return GetTemperature()*rSLtemperature; }
+
+  /// Returns the ratio of the temperature as modeled at the supplied altitude
+  /// over the standard sea level value.
+  virtual double GetTemperatureRatio(double h) const { return GetTemperature(h)*rSLtemperature; }
+
+  /// Returns the ratio of the standard temperature at the supplied altitude 
+  /// over the standard sea level temperature.
+  virtual double GetStdTemperatureRatio(double h) const { return GetStdTemperature(h)*rSLtemperature; }
+
+  /// Returns the temperature bias over the sea level value in degrees Rankine.
+  virtual double GetTemperatureBias(eTemperature to) const {return TemperatureBias;}
+
+  /// Returns the temperature gradient to be applied on top of the standard
+  /// temperature gradient.
+  virtual double GetTemperatureDeltaGradient() { return TemperatureDeltaGradient;}
+
+  /// Sets the Sea Level temperature, if it is to be different than the standard.
+  /// This function will calculate a bias - a difference - from the standard
+  /// atmosphere temperature and will apply that bias to the entire
+  /// temperature profile. This is one way to set the temperature bias. Using
+  /// the SetTemperatureBias function will replace the value calculated by
+  /// this function.
+  /// @param t the temperature value in the unit provided.
+  /// @param unit the unit of the temperature.
+  virtual void SetSLTemperature(double t, eTemperature unit=eFahrenheit);
+
+  /// Sets the temperature at the supplied altitude, if it is to be different
+  /// than the standard temperature.
+  /// This function will calculate a bias - a difference - from the standard
+  /// atmosphere temperature at the supplied altitude and will apply that
+  /// calculated bias to the entire temperature profile.
+  /// @param t The temperature value in the unit provided.
+  /// @param h The altitude in feet above sea level.
+  /// @param unit The unit of the temperature.
+  virtual void SetTemperature(double t, double h, eTemperature unit=eFahrenheit) {};
+
+  /// Sets the temperature bias to be added to the standard temperature at all altitudes.
+  /// This function sets the bias - the difference - from the standard
+  /// atmosphere temperature. This bias applies to the entire
+  /// temperature profile. Another way to set the temperature bias is to use the
+  /// SetSLTemperature function, which replaces the value calculated by
+  /// this function with a calculated bias.
+  /// @param t the temperature value in the unit provided.
+  /// @param unit the unit of the temperature.
+  virtual void SetTemperatureBias(double t, eTemperature unit=eFahrenheit);
+
+  /// Sets a Sea Level temperature delta that is ramped out by 86 km.
+  /// The value of the delta is used to calculate a delta gradient that is
+  /// applied to the temperature at all altitudes below 86 km (282152 ft). 
+  /// For instance, if a temperature of 20 degrees F is supplied, the delta
+  /// gradient would be 20/282152 - or, about 7.09E-5 degrees/ft. At sea level,
+  /// the full 20 degrees would be added to the standard temperature,
+  /// but that 20 degree delta would be reduced by 7.09E-5 degrees for every
+  /// foot of altitude above sea level, so that by 86 km, there would be no
+  /// further delta added to the standard temperature.
+  /// The graded delta can be used along with the a bias to tailor the
+  /// temperature profile as desired.
+  /// @param t the sea level temperature delta value in the unit provided.
+  /// @param unit the unit of the temperature.
+  virtual void SetSLTemperatureGradedDelta(double t, eTemperature unit=eFahrenheit);
+
+  /// Sets the temperature delta value at the supplied altitude/elevation above
+  /// sea level, to be added to the standard temperature and ramped out by
+  /// 86 km.
+  /// This function computes the sea level delta from the standard atmosphere
+  /// temperature at sea level.
+  /// @param t the temperature skew value in the unit provided.
+  /// @param unit the unit of the temperature.
+  virtual void SetTemperatureGradedDelta(double t, double h, eTemperature unit=eFahrenheit);
+
+  /// This function resets the model to apply no bias or delta gradient to the
+  /// temperature.
+  /// The delta gradient and bias values are reset to 0.0, and the standard
+  /// temperature is used for the entire temperature profile at all altitudes.
+  virtual void ResetSLTemperature();
+  //@}
+
+  //  *************************************************************************
+  /// @name Pressure access functions.
+  //@{
+  /// Returns the pressure in psf.
+  virtual double GetPressure(void)  const {return Pressure;}
+
+  /// Returns the pressure at a specified altitude in psf.
+  virtual double GetPressure(double altitude) const;
+
+  /// Returns the standard pressure at a specified altitude in psf
+  virtual double GetStdPressure100K(double altitude) const;
+
+  /// Returns the standard pressure at the specified altitude.
+  virtual double GetStdPressure(double altitude) const;
+
+  /// Returns the sea level pressure in psf.
+  virtual double GetPressureSL(void) const { return SLpressure; }
+
+  /// Returns the ratio of at-altitude pressure over the sea level value.
+  virtual double GetPressureRatio(void) const { return Pressure*rSLpressure; }
+
+  /** Sets the sea level pressure for modeling an off-standard pressure
+      profile. This could be useful in the case where the pressure at an
+      airfield is known or set for a particular simulation run.
+      @param pressure The pressure in the units specified (PSF by default).
+      @param unit the unit of measure that the specified pressure is
+                       supplied in.*/
+  virtual void SetSeaLevelPressure(double pressure, ePressure unit=ePSF);
+
+  /** Resets the sea level to the Standard sea level pressure, and recalculates
+      dependent parameters so that the pressure calculations are standard. */
+  virtual void ResetSLPressure();
+  //@}
+
+  //  *************************************************************************
+  /// @name Density access functions.
+  //@{
+  /** Returns the density in slugs/ft^3.
+      This function may only be used if Run() is called first. */
+  virtual double GetDensity(void)  const {return Density;}
+
+  /** Returns the density in slugs/ft^3 at a given altitude in ft. */
+  virtual double GetDensity(double altitude) const;
+
+  /// Returns the standard density at a specified altitude
+  virtual double GetStdDensity(double altitude) const;
+
+  /// Returns the sea level density in slugs/ft^3
+  virtual double GetDensitySL(void)  const { return SLdensity; }
+
+  /// Returns the ratio of at-altitude density over the sea level value.
+  virtual double GetDensityRatio(void) const { return Density*rSLdensity; }
+  //@}
+
+  //  *************************************************************************
+  /// @name Speed of sound access functions.
+  //@{
+  /// Returns the speed of sound in ft/sec.
+  virtual double GetSoundSpeed(void) const {return Soundspeed;}
+
+  /// Returns the sea level speed of sound in ft/sec.
+  virtual double GetSoundSpeedSL(void) const { return SLsoundspeed; }
+
+  /// Returns the ratio of at-altitude sound speed over the sea level value.
+  virtual double GetSoundSpeedRatio(void) const { return Soundspeed*rSLsoundspeed; }
+  //@}
+
+  //  *************************************************************************
+  /// @name Viscosity access functions.
+  //@{
+  /// Returns the absolute viscosity.
+  virtual double GetAbsoluteViscosity(void) const {return Viscosity;}
+
+  /// Returns the kinematic viscosity.
+  virtual double GetKinematicViscosity(void) const {return KinematicViscosity;}
+  //@}
+
+  /* /// Gets the density altitude in feet */
+//  virtual double GetDensityAltitude(void) const { return density_altitude; }
+
+  /// Prints the U.S. Standard Atmosphere table.
+  virtual void PrintStandardAtmosphereTable();
+
+protected:
+  double StdSLtemperature, StdSLdensity, StdSLpressure, StdSLsoundspeed; // Standard sea level conditions
+  double    SLtemperature,    SLdensity,    SLpressure,    SLsoundspeed; // Sea level conditions
+  double      Temperature,      Density,      Pressure,      Soundspeed; // Current actual conditions at altitude
+  double   rSLtemperature,   rSLdensity,   rSLpressure,   rSLsoundspeed; // Reciprocal of sea level conditions
+
+  double PressureAltitude;
+  double DensityAltitude;
+
+  double TemperatureBias;
+  double TemperatureDeltaGradient;
+  double GradientFadeoutAltitude;
+
+  FGTable* StdAtmosTemperatureTable;
+  std::vector<double> LapseRateVector;
+  std::vector<double> PressureBreakpointVector;
+
+  const double SutherlandConstant, Beta;
+  double Viscosity, KinematicViscosity;
+
+  /// Calculate the atmosphere for the given altitude, including effects of temperature deviation.
+  void Calculate(double altitude);
+
+  /// Recalculate the lapse rate vectors when the temperature profile is altered
+  /// in a way that would change the lapse rates, such as when a gradient is applied.
+  /// This function is also called to initialize the lapse rate vector.
+  void CalculateLapseRates();
+
+  /// Calculate (or recalculate) the atmospheric pressure breakpoints at the 
+  /// altitudes in the standard temperature table.
+  void CalculatePressureBreakpoints();
+
+  // Converts to Rankine from one of several unit systems.
+  virtual double ConvertToRankine(double t, eTemperature unit) const;
+  
+  // Converts to PSF (pounds per square foot) from one of several unit systems.
+  virtual double ConvertToPSF(double t, ePressure unit=ePSF) const;
+
+  virtual void bind(void);
+  void Debug(int from);
+};
+
+} // namespace JSBSim
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+#endif
+
diff --git a/src/FDM/JSBSim/models/flight_control/FGActuator.cpp b/src/FDM/JSBSim/models/flight_control/FGActuator.cpp
index bfbd25920..e7ab6aa65 100644
--- a/src/FDM/JSBSim/models/flight_control/FGActuator.cpp
+++ b/src/FDM/JSBSim/models/flight_control/FGActuator.cpp
@@ -43,7 +43,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGActuator.cpp,v 1.17 2011/02/13 00:42:45 jberndt Exp $";
+static const char *IdSrc = "$Id: FGActuator.cpp,v 1.18 2011/05/13 17:14:47 bcoconni Exp $";
 static const char *IdHdr = ID_ACTUATOR;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -125,6 +125,13 @@ bool FGActuator::Run(void )
   if (fail_stuck) Output = PreviousOutput;
   PreviousOutput = Output; // previous value needed for "stuck" malfunction
 
+  if (fcs->GetTrimStatus()) {
+    PreviousHystOutput = Output;
+    PreviousRateLimOutput = Output;
+    PreviousLagInput = Output;
+    PreviousLagOutput = Output;
+  }
+
   Clip();
   if (IsOutput) SetOutput();
 
diff --git a/src/FDM/JSBSim/models/flight_control/FGFCSComponent.cpp b/src/FDM/JSBSim/models/flight_control/FGFCSComponent.cpp
index 64a764927..2fc74bd96 100644
--- a/src/FDM/JSBSim/models/flight_control/FGFCSComponent.cpp
+++ b/src/FDM/JSBSim/models/flight_control/FGFCSComponent.cpp
@@ -48,7 +48,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGFCSComponent.cpp,v 1.30 2011/04/05 20:20:21 andgi Exp $";
+static const char *IdSrc = "$Id: FGFCSComponent.cpp,v 1.32 2011/06/16 03:39:38 jberndt Exp $";
 static const char *IdHdr = ID_FCSCOMPONENT;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -58,7 +58,7 @@ CLASS IMPLEMENTATION
 FGFCSComponent::FGFCSComponent(FGFCS* _fcs, Element* element) : fcs(_fcs)
 {
   Element *input_element, *clip_el;
-  Input = Output = clipmin = clipmax = 0.0;
+  Input = Output = clipmin = clipmax = delay_time = 0.0;
   treenode = 0;
   delay = index = 0;
   ClipMinPropertyNode = ClipMaxPropertyNode = 0;
@@ -149,18 +149,18 @@ FGFCSComponent::FGFCSComponent(FGFCS* _fcs, Element* element) : fcs(_fcs)
 
   Element* delay_elem = element->FindElement("delay");
   if ( delay_elem ) {
-    delay = (unsigned int)delay_elem->GetDataAsNumber();
+    delay_time = delay_elem->GetDataAsNumber();
     string delayType = delay_elem->GetAttributeValue("type");
     if (delayType.length() > 0) {
       if (delayType == "time") {
-        delay = (int)(delay / dt);
+        delay = (unsigned int)(delay_time / dt);
       } else if (delayType == "frames") {
-        // no op. the delay type of "frames" is assumed and is the default.
+        delay = (unsigned int)delay_time;
       } else {
         cerr << "Unallowed delay type" << endl;
       }
     } else {
-      delay = (int)(delay / dt);
+      delay = (unsigned int)(delay_time / dt);
     }
     output_array.resize(delay);
     for (int i=0; i<delay; i++) output_array[i] = 0.0;
diff --git a/src/FDM/JSBSim/models/flight_control/FGFCSComponent.h b/src/FDM/JSBSim/models/flight_control/FGFCSComponent.h
index 02bca98bd..d79a2e66c 100644
--- a/src/FDM/JSBSim/models/flight_control/FGFCSComponent.h
+++ b/src/FDM/JSBSim/models/flight_control/FGFCSComponent.h
@@ -46,7 +46,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_FCSCOMPONENT "$Id: FGFCSComponent.h,v 1.18 2011/04/05 20:20:21 andgi Exp $"
+#define ID_FCSCOMPONENT "$Id: FGFCSComponent.h,v 1.20 2011/06/16 03:39:38 jberndt Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -81,7 +81,7 @@ CLASS DOCUMENTATION
     - FGActuator
 
     @author Jon S. Berndt
-    @version $Id: FGFCSComponent.h,v 1.18 2011/04/05 20:20:21 andgi Exp $
+    @version $Id: FGFCSComponent.h,v 1.20 2011/06/16 03:39:38 jberndt Exp $
     @see Documentation for the FGFCS class, and for the configuration file class
 */
 
@@ -120,7 +120,8 @@ protected:
   double Input;
   double Output;
   double clipmax, clipmin;
-  int delay;
+  double delay_time;
+  unsigned int delay;
   int index;
   float clipMinSign, clipMaxSign;
   double dt;
diff --git a/src/FDM/JSBSim/models/flight_control/FGPID.cpp b/src/FDM/JSBSim/models/flight_control/FGPID.cpp
old mode 100644
new mode 100755
index 6556ecdb7..da6e6c16e
--- a/src/FDM/JSBSim/models/flight_control/FGPID.cpp
+++ b/src/FDM/JSBSim/models/flight_control/FGPID.cpp
@@ -44,7 +44,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGPID.cpp,v 1.16 2009/10/24 22:59:30 jberndt Exp $";
+static const char *IdSrc = "$Id: FGPID.cpp,v 1.19 2011/05/05 11:44:11 jberndt Exp $";
 static const char *IdHdr = ID_PID;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -144,10 +144,14 @@ bool FGPID::Run(void )
 
   if (Trigger != 0) {
     double test = Trigger->getDoubleValue();
-    if (fabs(test) < 0.000001) I_out_delta = Ki * dt * Input;  // Normal
+    if (fabs(test) < 0.000001) {
+      // I_out_delta = Ki * dt * Input;                         // Normal rectangular integrator
+      I_out_delta = Ki * dt * (1.5*Input - 0.5*Input_prev);  // 2nd order Adams Bashforth integrator
+    }
     if (test < 0.0)            I_out_total = 0.0;  // Reset integrator to 0.0
   } else { // no anti-wind-up trigger defined
-    I_out_delta = Ki * dt * Input;
+    // I_out_delta = Ki * dt * Input;
+    I_out_delta = Ki * dt * (1.5*Input - 0.5*Input_prev);  // 2nd order Adams Bashforth integrator
   }
   
   I_out_total += I_out_delta;
diff --git a/src/FDM/JSBSim/models/flight_control/FGSwitch.cpp b/src/FDM/JSBSim/models/flight_control/FGSwitch.cpp
index cea9f583e..9d56e512e 100644
--- a/src/FDM/JSBSim/models/flight_control/FGSwitch.cpp
+++ b/src/FDM/JSBSim/models/flight_control/FGSwitch.cpp
@@ -69,7 +69,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGSwitch.cpp,v 1.20 2011/04/05 20:20:21 andgi Exp $";
+static const char *IdSrc = "$Id: FGSwitch.cpp,v 1.21 2011/06/16 03:39:38 jberndt Exp $";
 static const char *IdHdr = ID_SWITCH;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -196,6 +196,7 @@ bool FGSwitch::Run(void )
   
   if (!pass) Output = default_output;
 
+  if (delay != 0) Delay();
   Clip();
   if (IsOutput) SetOutput();
 
diff --git a/src/FDM/JSBSim/models/propulsion/FGElectric.cpp b/src/FDM/JSBSim/models/propulsion/FGElectric.cpp
index cbcb9220a..341c02a39 100644
--- a/src/FDM/JSBSim/models/propulsion/FGElectric.cpp
+++ b/src/FDM/JSBSim/models/propulsion/FGElectric.cpp
@@ -42,6 +42,7 @@ INCLUDES
 #include "FGElectric.h"
 #include "models/FGPropulsion.h"
 #include "models/propulsion/FGThruster.h"
+#include "FGPropeller.h"
 
 #include <iostream>
 #include <sstream>
@@ -50,7 +51,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGElectric.cpp,v 1.10 2011/03/10 01:35:25 dpculp Exp $";
+static const char *IdSrc = "$Id: FGElectric.cpp,v 1.11 2011/06/06 22:35:08 jentron Exp $";
 static const char *IdHdr = ID_ELECTRIC;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -71,6 +72,11 @@ FGElectric::FGElectric(FGFDMExec* exec, Element *el, int engine_number)
   if (el->FindElement("power"))
     PowerWatts = el->FindElementValueAsNumberConvertTo("power","WATTS");
 
+  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);
+
   Debug(0); // Call Debug() routine from constructor if needed
 }
 
@@ -89,6 +95,11 @@ void FGElectric::Calculate(void)
 
   Throttle = FCS->GetThrottlePos(EngineNumber);
 
+  if (Thruster->GetType() == FGThruster::ttPropeller) {
+      ((FGPropeller*)Thruster)->SetAdvance(FCS->GetPropAdvance(EngineNumber));
+      ((FGPropeller*)Thruster)->SetFeather(FCS->GetPropFeather(EngineNumber));
+  } 
+
   RPM = Thruster->GetRPM() * Thruster->GetGearRatio();
 
   HP = PowerWatts * Throttle / hptowatts;
diff --git a/src/FDM/JSBSim/models/propulsion/FGPiston.cpp b/src/FDM/JSBSim/models/propulsion/FGPiston.cpp
index 7726306bf..c687b31e8 100644
--- 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 1.55 2011/03/10 01:35:25 dpculp Exp $";
+static const char *IdSrc = "$Id: FGPiston.cpp,v 1.58 2011/06/13 15:23:09 jentron Exp $";
 static const char *IdHdr = ID_PISTON;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -64,7 +64,7 @@ FGPiston::FGPiston(FGFDMExec* exec, Element* el, int engine_number)
   : FGEngine(exec, el, engine_number),
   R_air(287.3),                  // Gas constant for air J/Kg/K
   rho_fuel(800),                 // estimate
-  calorific_value_fuel(47.3e6),
+  calorific_value_fuel(47.3e6),  // J/Kg
   Cp_air(1005),                  // Specific heat (constant pressure) J/Kg/K
   Cp_fuel(1700),
   standard_pressure(101320.73)
@@ -100,6 +100,7 @@ FGPiston::FGPiston(FGFDMExec* exec, Element* el, int engine_number)
   FMEPDynamic= 18400;
   FMEPStatic = 46500;
   Cooling_Factor = 0.5144444;
+  StaticFriction_HP = 1.5;
 
   // These are internal program variables
 
@@ -177,6 +178,8 @@ FGPiston::FGPiston(FGFDMExec* exec, Element* el, int engine_number)
     Displacement = el->FindElementValueAsNumberConvertTo("displacement","IN3");
   if (el->FindElement("maxhp"))
     MaxHP = el->FindElementValueAsNumberConvertTo("maxhp","HP");
+  if (el->FindElement("static-friction"))
+    StaticFriction_HP = el->FindElementValueAsNumberConvertTo("static-friction","HP");
   if (el->FindElement("sparkfaildrop"))
     SparkFailDrop = Constrain(0, 1 - el->FindElementValueAsNumber("sparkfaildrop"), 1);
   if (el->FindElement("cycles"))
@@ -259,7 +262,7 @@ FGPiston::FGPiston(FGFDMExec* exec, Element* el, int engine_number)
       pmep *= inhgtopa  * volumetric_efficiency;
       double fmep = (FMEPDynamic * RatedMeanPistonSpeed_fps * fttom + FMEPStatic);
       double hp_loss = ((pmep + fmep) * displacement_SI * MaxRPM)/(Cycles*22371);
-      ISFC = ( 1.1*Displacement * MaxRPM * volumetric_efficiency *(MaxManifoldPressure_inHg / 29.92) ) / (9411 * (MaxHP+hp_loss));
+      ISFC = ( 1.1*Displacement * MaxRPM * volumetric_efficiency *(MaxManifoldPressure_inHg / 29.92) ) / (9411 * (MaxHP+hp_loss-StaticFriction_HP));
 // cout <<"FMEP: "<< fmep <<" PMEP: "<< pmep << " hp_loss: " <<hp_loss <<endl;
   }
   if ( MaxManifoldPressure_inHg > 29.9 ) {   // Don't allow boosting with a bogus number
@@ -314,6 +317,14 @@ FGPiston::FGPiston(FGFDMExec* exec, Element* el, int engine_number)
   PropertyManager->Tie(property_name, &BoostSpeed);
   property_name = base_property_name + "/cht-degF";
   PropertyManager->Tie(property_name, this, &FGPiston::getCylinderHeadTemp_degF);
+  property_name = base_property_name + "/engine-rpm";
+  PropertyManager->Tie(property_name, this, &FGPiston::getRPM);
+  property_name = base_property_name + "/oil-temperature-degF";
+  PropertyManager->Tie(property_name, this, &FGPiston::getOilTemp_degF);
+  property_name = base_property_name + "/oil-pressure-psi";
+  PropertyManager->Tie(property_name, this, &FGPiston::getOilPressure_psi);
+  property_name = base_property_name + "/egt-degF";
+  PropertyManager->Tie(property_name, this, &FGPiston::getExhaustGasTemp_degF);
 
   // Set up and sanity-check the turbo/supercharging configuration based on the input values.
   if (TakeoffBoost > RatedBoost[0]) bTakeoffBoost = true;
@@ -730,7 +741,7 @@ void FGPiston::doEnginePower(void)
   // (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
+  HP = IndicatedHorsePower + pumping_hp - StaticFriction_HP; //FIXME 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;
@@ -756,11 +767,10 @@ void FGPiston::doEGT(void)
   if ((Running) && (m_dot_air > 0.0)) {  // do the energy balance
     combustion_efficiency = Lookup_Combustion_Efficiency->GetValue(equivalence_ratio);
     enthalpy_exhaust = m_dot_fuel * calorific_value_fuel *
-                              combustion_efficiency * 0.33;
+                              combustion_efficiency * 0.30;
     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) * PctPower);
   } else {  // Drop towards ambient - guess an appropriate time constant for now
     combustion_efficiency = 0;
     dEGTdt = (RankineToKelvin(Atmosphere->GetTemperature()) - ExhaustGasTemp_degK) / 100.0;
diff --git a/src/FDM/JSBSim/models/propulsion/FGPiston.h b/src/FDM/JSBSim/models/propulsion/FGPiston.h
index a8019e5aa..4a536b5d0 100644
--- 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 1.26 2011/03/10 01:35:25 dpculp Exp $";
+#define ID_PISTON "$Id: FGPiston.h,v 1.29 2011/06/16 16:32:10 jentron Exp $";
 #define FG_MAX_BOOST_SPEEDS 3
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -59,7 +59,7 @@ namespace JSBSim {
 CLASS DOCUMENTATION
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-/** Models Dave Luff's Turbo/Supercharged Piston engine model.
+/** Models a Supercharged Piston engine. Based on Dave Luff's model.
 
 <h3>Configuration File Format:</h3>
 
@@ -67,19 +67,21 @@ CLASS DOCUMENTATION
 <piston_engine name="{string}">
   <minmp unit="{INHG | PA | ATM}"> {number} </minmp>
   <maxmp unit="{INHG | PA | ATM}"> {number} </maxmp>
+  <idlerpm> {number} </idlerpm>
+  <maxrpm> {number} </maxrpm>
+  <maxhp unit="{HP | WATTS}"> {number} </maxhp>
   <displacement unit="{IN3 | LTR | CC}"> {number} </displacement>
+  <cycles> {number} </cycles>
   <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>
-  <cycles> {number} </cycles>
-  <idlerpm> {number} </idlerpm>
-  <maxrpm> {number} </maxrpm>
-  <maxthrottle> {number} </maxthrottle>
-  <minthrottle> {number} </minthrottle>
+  <static-friction unit="{HP | WATTS}"> {number} </static-friction>
+  <air-intake-impedance-factor> {number} </air-intake-impedance-factor>
+  <ram-air-factor> {number} </ram-air-factor>
+  <cooling-factor> {number} </cooling-factor>
+  <cylinder-head-mass unit="{KG | LBS}"> {number} </cylinder-head-mass>
   <bsfc unit="{LBS/HP*HR | "KG/KW*HR"}"> {number} </bsfc>
   <volumetric-efficiency> {number} </volumetric-efficiency>
   <dynamic-fmep unit="{INHG | PA | ATM}"> {number} </dynamic-fmep>
@@ -100,89 +102,103 @@ CLASS DOCUMENTATION
   <ratedrpm3> {number} </ratedrpm3>
   <ratedaltitude3 unit="{FT | M}"> {number} </ratedaltitude3>
   <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
 
-<pre>
-    Additional elements are required for a supercharged engine.  These can be
-    left off a non-supercharged engine, ie. the changes are all backward
-    compatible at present.
-
-    - NUMBOOSTSPEEDS - zero (or not present) for a naturally-aspirated engine,
+<h3>Definition of the piston engine configuration file parameters:</h3>
+Basic parameters:
+- \b minmp - this value is the nominal idle manifold pressure at sea-level
+      without boost. Along with idlerpm, it determines throttle response slope.
+- \b maxmp - this value is the nominal maximum manifold pressure at sea-level
+      without boost. Along with maxrpm it determines the resistance of the
+      aircraft intake system. Overridden by air-intake-impedance-factor
+- \b idlerpm - this value affects the throttle fall off and the engine stops
+      running if it is slowed below 80% of this value. The engine starts
+      running when it reaches 80% of this value.
+- \b maxrpm - this value is used to calculate air-box resistance and BSFC. It 
+      also affects oil pressure among other things.
+- \b maxhp - this value is the nominal power the engine creates at maxrpm. It
+      will determine bsfc if that tag is not input. It also determines the
+      starter motor power.
+- \b displacement - this value is used to determine mass air and fuel flow
+      which impacts engine power and cooling.
+- \b cycles - Designate a 2 or 4 stroke engine. Currently only the 4 stroke
+      engine is supported.
+- \b bore - cylinder bore is currently unused.
+- \b stroke - piston stroke is used to determine the mean piston speed. Longer
+      strokes result in an engine that does not work as well at higher RPMs.
+- \b compression-ratio - the compression ratio affects the change in volumetric
+      efficiency with altitude.
+- \b sparkfaildrop - this is the percentage drop in horsepower for single
+      magneto operation.
+- \b static-friction - this value is the power required to turn an engine that 
+      is not running. Used to control and slow a windmilling propeller. Choose
+      a small percentage of maxhp.
+
+Advanced parameters
+- \b bsfc - Indicated Specific Fuel Consumption. The power produced per unit of
+      fuel. Higher numbers give worse fuel economy. This number may need to be
+      lowered slightly from actual BSFC numbers because some internal engine 
+      losses are modeled separately. Typically between 0.3 and 0.5
+- \b volumetric-efficiency - the nominal volumetric efficiency of the engine.
+      This is the primary way to control fuel flow  Boosted engines may require
+      values above 1. Typical engines are 0.80 to 0.82
+- \b air-intake-impedance-factor - this number is the pressure drop across the
+      intake system. Increasing it reduces available manifold pressure. Also a 
+      property for run-time adjustment.
+- \b ram-air-factor - this number creates increases manifold pressure with an
+      increase in dynamic pressure (aircraft speed).
+      Also a property for run-time adjustment.
+
+Cooling control:
+- \b cylinders  - number of cylinders scales the cylinder head mass.
+- \b cylinder-head-mass - the nominal mass of a cylinder head. A larger value
+      slows changes in engine temperature
+- \b cooling-factor - this number models the efficiency of the aircraft cooling
+      system. Also a property for run-time adjustment.
+
+Supercharge parameters:
+- \b numboostspeed -  zero (or not present) for a naturally-aspirated engine,
       either 1, 2 or 3 for a boosted engine.  This corresponds to the number of
       supercharger speeds.  Merlin XII had 1 speed, Merlin 61 had 2, a late
       Griffon engine apparently had 3.  No known engine more than 3, although
-      some German engines apparently had a continuously variable-speed
-      supercharger.
-
-    - BOOSTOVERRIDE - whether the boost pressure control system (either a boost
-      control valve for superchargers or wastegate for turbochargers) can be
-      overriden by the pilot.  During wartime this was commonly possible, and
-      known as "War Emergency Power" by the Brits.  1 or 0 in the config file.
-      This isn't implemented in the model yet though, there would need to be
-      some way of getting the boost control cutout lever position (on or off)
-      from FlightGear first.
-
-    - BOOSTMANUAL - whether a multispeed supercharger will manually or
-      automatically shift boost speeds.  On manual shifting the boost speeds
-      is accomplished by controling propulsion/engine/boostspeed
-
-    - The next items are all appended with either 1, 2 or 3 depending on which
-      boost speed they refer to, eg RATEDBOOST1.  The rated values seems to have
-      been a common convention at the time to express the maximum continuously
-      available power, and the conditions to attain that power.
-
-    - RATEDBOOST[123] - the absolute rated boost above sea level ambient for a
-      given boost speed, in psi.  Eg the Merlin XII had a rated boost of 9psi,
-      giving approximately 42inHg manifold pressure up to the rated altitude.
-
-    - RATEDALTITUDE[123] - The altitude up to which rated boost can be
-      maintained.  Up to this altitude the boost is maintained constant for a
-      given throttle position by the BCV or wastegate.  Beyond this altitude the
-      manifold pressure must drop, since the supercharger is now at maximum
-      unregulated output.  The actual pressure multiplier of the supercharger
-      system is calculated at initialisation from this value.
-
-    - RATEDPOWER[123] - The power developed at rated boost at rated altitude at
-      rated rpm.
-
-    - RATEDRPM[123] - The rpm at which rated power is developed.
-
-    - TAKEOFFBOOST - Takeoff boost in psi above ambient.  Many aircraft had an
-      extra boost setting beyond rated boost, but not totally uncontrolled as in
-      the already mentioned boost-control-cutout, typically attained by pushing
-      the throttle past a mechanical 'gate' preventing its inadvertant use. This
-      was typically used for takeoff, and emergency situations, generally for
-      not more than five minutes.  This is a change in the boost control
-      setting, not the actual supercharger speed, and so would only give extra
-      power below the rated altitude.  When TAKEOFFBOOST is specified in the
-      config file (and is above RATEDBOOST1), then the throttle position is
-      interpreted as:
-
-    - 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
-    with a rated boost of 9psi.
-
-    It is quite possible that other boost control settings could have been used
-    on some aircraft, or that takeoff/extra boost could have activated by other
-    means than pushing the throttle full forward through a gate, but this will
-    suffice for now.
-
-    Note that MAXMP is still the non-boosted max manifold pressure even for
-    boosted engines - effectively this is simply a measure of the pressure drop
-    through the fully open throttle.
-</pre>
+      some German engines had continuously variable-speed superchargers.
+- \b boostoverride - unused
+- \b boostmanual - whether a multispeed supercharger will manually or
+      automatically shift boost speeds. On manual shifting the boost speeds is
+      accomplished by controlling the property propulsion/engine/boostspeed.
+- \b takeoffboost - boost in psi above sea level ambient. Typically used for
+      takeoff, and emergency situations, generally for not more than five
+      minutes.  This is a change in the boost control setting, not the actual
+      supercharger speed, and so would only give extra power below the rated altitude.
+      A typical takeoff boost for an early Merlin was about 12psi, compared
+      with a rated boost of 9psi.
+
+      When TAKEOFFBOOST is specified in the config file (and is above RATEDBOOST1), 
+      the throttle position is interpreted as:
+     - 0 to 0.98 : idle manifold pressure to rated boost (where attainable)
+     - 0.99, 1.0 : takeoff boost (where attainable).
+
+The next items are all appended with either 1, 2 or 3 depending on which
+boostspeed they refer to:
+- \b ratedboost[123] - the absolute rated boost above sea level ambient
+      (14.7 PSI, 29.92 inHg) for a given boost speed.
+
+- \b ratedpower[123] - unused
+- \b ratedrpm[123] - The rpm at which rated boost is developed
+- \b ratedaltitude[123] - The altitude up to which the rated boost can be
+      maintained. Up to this altitude the boost is clipped to rated boost or
+      takeoffboost. Beyond this altitude the manifold pressure must drop,
+      since the supercharger is now at maximum unregulated output. The actual
+      pressure multiplier of the supercharger system is calculated at
+      initialization from this value.
 
     @author Jon S. Berndt (Engine framework code and framework-related mods)
     @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 1.26 2011/03/10 01:35:25 dpculp Exp $
+    @see Taylor, Charles Fayette, "The Internal Combustion Engine in Theory and Practice"
+    @version $Id: FGPiston.h,v 1.29 2011/06/16 16:32:10 jentron Exp $
   */
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -250,7 +266,7 @@ private:
 
   const double R_air;
   const double rho_fuel;    // kg/m^3
-  const double calorific_value_fuel;  // W/Kg (approximate)
+  const double calorific_value_fuel;  // J/Kg (approximate)
   const double Cp_air;      // J/KgK
   const double Cp_fuel;     // J/KgK
   const double standard_pressure; //Pa
@@ -268,6 +284,7 @@ private:
   double Displacement;             // cubic inches
   double displacement_SI;          // cubic meters
   double MaxHP;                    // horsepower
+  double StaticFriction_HP;        // horsepower: amount subtracted from final engine power
   double SparkFailDrop;            // drop of power due to spark failure
   double Cycles;                   // cycles/power stroke
   double IdleRPM;                  // revolutions per minute
@@ -284,29 +301,29 @@ private:
   double Ram_Air_Factor;           // 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).
-  bool Boosted;		// Set true for boosted engine.
-  int BoostManual;	// The raw value read in from the config file - should be 1 or 0 - see description below.
-  bool bBoostManual;	// Set true if pilot must manually control the boost speed.
-  int BoostOverride;	// The raw value read in from the config file - should be 1 or 0 - see description below.
-  bool bBoostOverride;	// Set true if pilot override of the boost regulator was fitted.
+  int BoostSpeeds;  // Number of super/turbocharger boost speeds - zero implies no turbo/supercharging.
+  int BoostSpeed;   // The current boost-speed (zero-based).
+  bool Boosted;     // Set true for boosted engine.
+  int BoostManual;  // The raw value read in from the config file - should be 1 or 0 - see description below.
+  bool bBoostManual;    // Set true if pilot must manually control the boost speed.
+  int BoostOverride;    // The raw value read in from the config file - should be 1 or 0 - see description below.
+  bool bBoostOverride;  // Set true if pilot override of the boost regulator was fitted.
               // (Typically called 'war emergency power').
-  bool bTakeoffBoost;	// Set true if extra takeoff / emergency boost above rated boost could be attained.
+  bool bTakeoffBoost;   // Set true if extra takeoff / emergency boost above rated boost could be attained.
               // (Typically by extra throttle movement past a mechanical 'gate').
-  double TakeoffBoost;	// Sea-level takeoff boost in psi. (if fitted).
-  double RatedBoost[FG_MAX_BOOST_SPEEDS];	// Sea-level rated boost in psi.
-  double RatedAltitude[FG_MAX_BOOST_SPEEDS];	// Altitude at which full boost is reached (boost regulation ends)
+  double TakeoffBoost;  // Sea-level takeoff boost in psi. (if fitted).
+  double RatedBoost[FG_MAX_BOOST_SPEEDS];   // Sea-level rated boost in psi.
+  double RatedAltitude[FG_MAX_BOOST_SPEEDS];    // Altitude at which full boost is reached (boost regulation ends)
                           // and at which power starts to fall with altitude [ft].
   double RatedRPM[FG_MAX_BOOST_SPEEDS]; // Engine speed at which the rated power for each boost speed is delivered [rpm].
-  double RatedPower[FG_MAX_BOOST_SPEEDS];	// Power at rated throttle position at rated altitude [HP].
-  double BoostSwitchAltitude[FG_MAX_BOOST_SPEEDS - 1];	// Altitude at which switchover (currently assumed automatic)
+  double RatedPower[FG_MAX_BOOST_SPEEDS];   // Power at rated throttle position at rated altitude [HP].
+  double BoostSwitchAltitude[FG_MAX_BOOST_SPEEDS - 1];  // Altitude at which switchover (currently assumed automatic)
                               // from one boost speed to next occurs [ft].
   double BoostSwitchPressure[FG_MAX_BOOST_SPEEDS - 1];  // Pressure at which boost speed switchover occurs [Pa]
-  double BoostMul[FG_MAX_BOOST_SPEEDS];	// Pressure multipier of unregulated supercharger
-  double RatedMAP[FG_MAX_BOOST_SPEEDS];	// Rated manifold absolute pressure [Pa] (BCV clamp)
-  double TakeoffMAP[FG_MAX_BOOST_SPEEDS];	// Takeoff setting manifold absolute pressure [Pa] (BCV clamp)
-  double BoostSwitchHysteresis;	// Pa.
+  double BoostMul[FG_MAX_BOOST_SPEEDS]; // Pressure multipier of unregulated supercharger
+  double RatedMAP[FG_MAX_BOOST_SPEEDS]; // Rated manifold absolute pressure [Pa] (BCV clamp)
+  double TakeoffMAP[FG_MAX_BOOST_SPEEDS];   // Takeoff setting manifold absolute pressure [Pa] (BCV clamp)
+  double BoostSwitchHysteresis; // Pa.
 
   double minMAP;  // Pa
   double maxMAP;  // Pa
diff --git a/src/FDM/JSBSim/models/propulsion/FGPropeller.cpp b/src/FDM/JSBSim/models/propulsion/FGPropeller.cpp
index d5ed3813d..64ae65574 100644
--- a/src/FDM/JSBSim/models/propulsion/FGPropeller.cpp
+++ b/src/FDM/JSBSim/models/propulsion/FGPropeller.cpp
@@ -48,7 +48,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGPropeller.cpp,v 1.33 2011/03/10 01:35:25 dpculp Exp $";
+static const char *IdSrc = "$Id: FGPropeller.cpp,v 1.34 2011/06/16 14:54:06 jentron Exp $";
 static const char *IdHdr = ID_PROPELLER;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -102,8 +102,7 @@ FGPropeller::FGPropeller(FGFDMExec* exec, Element* prop_element, int num)
     ConstantSpeed = (int)prop_element->FindElementValueAsNumber("constspeed");
   if (prop_element->FindElement("reversepitch"))
     ReversePitch = prop_element->FindElementValueAsNumber("reversepitch");
-  for (int i=0; i<2; i++) {
-    table_element = prop_element->FindNextElement("table");
+  while(table_element = prop_element->FindNextElement("table")) {
     name = table_element->GetAttributeValue("name");
     try {
       if (name == "C_THRUST") {
@@ -121,6 +120,9 @@ FGPropeller::FGPropeller(FGFDMExec* exec, Element* prop_element, int num)
       throw("Error loading propeller table:" + name + ". " + str);
     }
   }
+  if( (cPower == 0) || (cThrust == 0)){
+      cerr << "Propeller configuration must contain C_THRUST and C_POWER tables!" << endl;
+  }
 
   local_element = prop_element->GetParent()->FindElement("sense");
   if (local_element) {
@@ -132,7 +134,7 @@ FGPropeller::FGPropeller(FGFDMExec* exec, Element* prop_element, int num)
     P_Factor = local_element->GetDataAsNumber();
   }
   if (P_Factor < 0) {
-    cerr << "P-Factor value in config file must be greater than zero" << endl;
+    cerr << "P-Factor value in propeller configuration file must be greater than zero" << endl;
   }
   if (prop_element->FindElement("ct_factor"))
     SetCtFactor( prop_element->FindElementValueAsNumber("ct_factor") );
@@ -424,10 +426,25 @@ void FGPropeller::Debug(int from)
       cout << "      Maximum Pitch  = " << MaxPitch << endl;
       cout << "      Minimum RPM  = " << MinRPM << endl;
       cout << "      Maximum RPM  = " << MaxRPM << endl;
+// Tables are being printed elsewhere...
 //      cout << "      Thrust Coefficient: " <<  endl;
 //      cThrust->Print();
 //      cout << "      Power Coefficient: " <<  endl;
 //      cPower->Print();
+//      cout << "      Mach Thrust Coefficient: " <<  endl;
+//      if(CtMach)
+//      {
+//          CtMach->Print();
+//      } else {
+//          cout << "        NONE" <<  endl;
+//      }
+//      cout << "      Mach Power Coefficient: " <<  endl;
+//      if(CpMach)
+//      {
+//          CpMach->Print();
+//      } else {
+//          cout << "        NONE" <<  endl;
+//      }
     }
   }
   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
diff --git a/src/FDM/JSBSim/models/propulsion/FGPropeller.h b/src/FDM/JSBSim/models/propulsion/FGPropeller.h
index 3e9c3c259..94fb454ec 100644
--- a/src/FDM/JSBSim/models/propulsion/FGPropeller.h
+++ b/src/FDM/JSBSim/models/propulsion/FGPropeller.h
@@ -45,7 +45,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_PROPELLER "$Id: FGPropeller.h,v 1.17 2011/03/10 01:35:25 dpculp Exp $"
+#define ID_PROPELLER "$Id: FGPropeller.h,v 1.18 2011/06/06 22:39:52 jentron Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -62,6 +62,7 @@ CLASS DOCUMENTATION
 
 <h3>Configuration File Format:</h3>
 @code
+<sense> {1 | -1} </sense> 
 <propeller name="{string}">
   <ixx> {number} </ixx>
   <diameter unit="IN"> {number} </diameter>
@@ -73,7 +74,6 @@ CLASS DOCUMENTATION
   <maxrpm> {number} </maxrpm>
   <constspeed> {number} </constspeed>
   <reversepitch> {number} </reversepitch>
-  <sense> {1 | -1} </sense>
   <p_factor> {number} </p_factor>
   <ct_factor> {number} </ct_factor>
   <cp_factor> {number} </cp_factor>
@@ -119,7 +119,8 @@ CLASS DOCUMENTATION
     \<constspeed>    - 1 = constant speed mode, 0 = manual pitch mode. 
     \<reversepitch>  - Blade pitch angle for reverse.
     \<sense>         - Direction of rotation (1=clockwise as viewed from cockpit,
-                        -1=anti-clockwise as viewed from cockpit).
+                        -1=anti-clockwise as viewed from cockpit). Sense is
+                       specified in the parent tag of the propeller.
     \<p_factor>      - P factor.
     \<ct_factor>     - A multiplier for the coefficients of thrust.
     \<cp_factor>     - A multiplier for the coefficients of power.
@@ -141,7 +142,7 @@ CLASS DOCUMENTATION
     <li>Various NACA Technical Notes and Reports</li>
     </ul>
     @author Jon S. Berndt
-    @version $Id: FGPropeller.h,v 1.17 2011/03/10 01:35:25 dpculp Exp $
+    @version $Id: FGPropeller.h,v 1.18 2011/06/06 22:39:52 jentron Exp $
     @see FGEngine
     @see FGThruster
 */
diff --git a/src/FDM/JSBSim/models/propulsion/FGTank.cpp b/src/FDM/JSBSim/models/propulsion/FGTank.cpp
index c9d38dab8..dbb5b37d1 100644
--- a/src/FDM/JSBSim/models/propulsion/FGTank.cpp
+++ b/src/FDM/JSBSim/models/propulsion/FGTank.cpp
@@ -48,7 +48,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGTank.cpp,v 1.28 2010/01/24 19:26:04 jberndt Exp $";
+static const char *IdSrc = "$Id: FGTank.cpp,v 1.29 2011/06/06 22:39:52 jentron Exp $";
 static const char *IdHdr = ID_TANK;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -66,6 +66,7 @@ FGTank::FGTank(FGFDMExec* exec, Element* el, int tank_number)
   InitialTemperature = Temperature = -9999.0;
   Ixx = Iyy = Izz = 0.0;
   Radius = Contents = Standpipe = Length = InnerRadius = 0.0;
+  ExternalFlow = 0.0;
   InitialStandpipe = 0.0;
   Capacity = 0.00001;
   Priority = InitialPriority = 1;
@@ -162,6 +163,9 @@ FGTank::FGTank(FGFDMExec* exec, Element* el, int tank_number)
   property_name = base_property_name + "/priority";
   PropertyManager->Tie( property_name.c_str(), (FGTank*)this, &FGTank::GetPriority,
                                        &FGTank::SetPriority );
+  property_name = base_property_name + "/external-flow-rate-pps";
+  PropertyManager->Tie( property_name.c_str(), (FGTank*)this, &FGTank::GetExternalFlow,
+                                       &FGTank::SetExternalFlow );
 
   if (Temperature != -9999.0)  InitialTemperature = Temperature = FahrenheitToCelsius(Temperature);
   Area = 40.0 * pow(Capacity/1975, 0.666666667);
@@ -269,6 +273,9 @@ void FGTank::SetContentsGallons(double gallons)
 
 double FGTank::Calculate(double dt)
 {
+  if(ExternalFlow < 0.) Drain( -ExternalFlow *dt);
+  else Fill(ExternalFlow * dt);
+
   if (Temperature == -9999.0) return 0.0;
   double HeatCapacity = 900.0;        // Joules/lbm/C
   double TempFlowFactor = 1.115;      // Watts/sqft/C
@@ -278,6 +285,7 @@ double FGTank::Calculate(double dt)
   if (fabs(Tdiff) > 0.1) {
     dTemp = (TempFlowFactor * Area * Tdiff * dt) / (Contents * HeatCapacity);
   }
+
   return Temperature += (dTemp + dTemp);    // For now, assume upper/lower the same
 }
 
diff --git a/src/FDM/JSBSim/models/propulsion/FGTank.h b/src/FDM/JSBSim/models/propulsion/FGTank.h
index 12e7e5fc9..4bf420a38 100644
--- a/src/FDM/JSBSim/models/propulsion/FGTank.h
+++ b/src/FDM/JSBSim/models/propulsion/FGTank.h
@@ -52,7 +52,7 @@ INCLUDES
 DEFINITIONS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
-#define ID_TANK "$Id: FGTank.h,v 1.21 2010/02/05 05:53:00 jberndt Exp $"
+#define ID_TANK "$Id: FGTank.h,v 1.23 2011/06/13 15:23:09 jentron Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -100,7 +100,16 @@ CLASS DOCUMENTATION
     tree at <tt>propulsion/tank[i]/contents-lbs</tt>, where i is the tank number (Tanks
     are automatically numbered, starting at zero, in the order in which they are read in
     the aircraft configuration file).  The latter method allows one to use a system of FCS
-    components to control tank contents. 
+    components to control tank contents.
+
+    There is also a property <tt>propulsion/tank[i]/external-flow-rate-pps</tt>. Setting
+    this property to a positive value causes the tank to fill at the rate specified.
+    Setting a negative number causes the tank to drain. The value is the rate in pounds
+    of fuel per second. The tank will not fill past 100% full and will not drain below 0%.
+    Fuel may be transfered between two tanks by setting the source tank's external flow rate
+    to a negative value and the destination's external flow rate to the same positive value.
+    Care must be taken to stop fuel flow before the source tank becomes empty to prevent
+    phantom fuel being created.
 
 <h3>Configuration File Format:</h3>
 
@@ -275,6 +284,9 @@ public:
   double GetDensity(void) const {return Density;}
   void   SetDensity(double d) { Density = d; }
 
+  double GetExternalFlow(void) const {return ExternalFlow;}
+  void   SetExternalFlow(double f) { ExternalFlow = f; }
+
   const FGColumnVector3 GetXYZ(void);
   const double GetXYZ(int idx);
 
@@ -309,6 +321,7 @@ private:
   double Area;
   double Temperature, InitialTemperature;
   double Standpipe, InitialStandpipe;
+  double ExternalFlow;
   bool  Selected;
   int Priority, InitialPriority;
   FGFDMExec* Exec;
diff --git a/src/FDM/JSBSim/models/propulsion/FGTurbine.cpp b/src/FDM/JSBSim/models/propulsion/FGTurbine.cpp
index d7277ba87..c4cfc3033 100644
--- a/src/FDM/JSBSim/models/propulsion/FGTurbine.cpp
+++ b/src/FDM/JSBSim/models/propulsion/FGTurbine.cpp
@@ -51,7 +51,7 @@ using namespace std;
 
 namespace JSBSim {
 
-static const char *IdSrc = "$Id: FGTurbine.cpp,v 1.31 2011/03/03 12:16:26 jberndt Exp $";
+static const char *IdSrc = "$Id: FGTurbine.cpp,v 1.32 2011/06/07 00:28:03 jentron Exp $";
 static const char *IdHdr = ID_TURBINE;
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -360,7 +360,7 @@ double FGTurbine::Seize(void)
 
 double FGTurbine::Trim()
 {
-    double idlethrust, milthrust, thrust, tdiff;
+    double idlethrust, milthrust, thrust, tdiff, N2, N2norm;
     idlethrust = MilThrust * IdleThrustLookup->GetValue();
     milthrust = (MilThrust - idlethrust) * MilThrustLookup->GetValue();
     N2 = IdleN2 + ThrottlePos * N2_factor;
diff --git a/src/FDM/JSBSim/models/propulsion/FGTurbine.h b/src/FDM/JSBSim/models/propulsion/FGTurbine.h
index 62c6d321a..907d08dd2 100644
--- a/src/FDM/JSBSim/models/propulsion/FGTurbine.h
+++ b/src/FDM/JSBSim/models/propulsion/FGTurbine.h
@@ -42,7 +42,7 @@ INCLUDES
 
 #include "FGEngine.h"
 
-#define ID_TURBINE "$Id: FGTurbine.h,v 1.19 2010/08/21 18:08:46 jberndt Exp $"
+#define ID_TURBINE "$Id: FGTurbine.h,v 1.20 2011/06/07 00:28:03 jentron Exp $"
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 FORWARD DECLARATIONS
@@ -93,6 +93,8 @@ CLASS DOCUMENTATION
   <atsfc> {number} </atsfc>
   <idlen1> {number} </idlen1>
   <idlen2> {number} </idlen2>
+  <n1spinup> {number} </n1spinup>
+  <n2spinup> {number} </n2spinup>
   <maxn1> {number} </maxn1>
   <maxn2> {number} </maxn2>
   <augmented> {0 | 1} </augmented>
@@ -113,6 +115,8 @@ CLASS DOCUMENTATION
   atsfc       - Afterburning TSFC, lbm/hr/lbf
   idlen1      - Fan rotor rpm (% of max) at idle
   idlen2      - Core rotor rpm (% of max) at idle
+  n1spinup    - Fan rotor rpm starter acceleration (default 1.0)
+  n2spinup    - Core rotor rpm starter acceleration (default 3.0)
   maxn1       - Fan rotor rpm (% of max) at full throttle 
   maxn2       - Core rotor rpm (% of max) at full throttle
   augmented
@@ -146,7 +150,7 @@ CLASS DOCUMENTATION
     /engine/direct.xml
 </pre>
     @author David P. Culp
-    @version "$Id: FGTurbine.h,v 1.19 2010/08/21 18:08:46 jberndt Exp $"
+    @version "$Id: FGTurbine.h,v 1.20 2011/06/07 00:28:03 jentron Exp $"
 */
 
 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%