2c3fa12eea
This version handles a zero fuel load better. I found that if you try to consume fuel from an empty tank, with zero fuel flow, the FGEngine::Starved flag alternates
267 lines
8.1 KiB
C++
267 lines
8.1 KiB
C++
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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Module: FGSimTurbine.cpp
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Author: David Culp
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Date started: 03/11/2003
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Purpose: This module models a turbine engine.
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------------- Copyright (C) 2003 David Culp (davidculp2@attbi.com) -----------
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; either version 2 of the License, or (at your option) any later
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version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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Place - Suite 330, Boston, MA 02111-1307, USA.
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Further information about the GNU General Public License can also be found on
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the world wide web at http://www.gnu.org.
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FUNCTIONAL DESCRIPTION
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--------------------------------------------------------------------------------
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This class descends from the FGEngine class and models a Turbine engine based
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on parameters given in the engine config file for this class
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HISTORY
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--------------------------------------------------------------------------------
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03/11/2003 DPC Created
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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INCLUDES
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
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#include <vector>
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#include "FGSimTurbine.h"
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namespace JSBSim {
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static const char *IdSrc = "$Id$";
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static const char *IdHdr = ID_SIMTURBINE;
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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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CLASS IMPLEMENTATION
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
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FGSimTurbine::FGSimTurbine(FGFDMExec* exec, FGConfigFile* cfg) : FGEngine(exec)
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{
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SetDefaults();
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FGEngine::Type=etSimTurbine;
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Load(cfg);
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Debug(0);
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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FGSimTurbine::~FGSimTurbine()
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{
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Debug(1);
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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double FGSimTurbine::Calculate(double dummy)
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{
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double idlethrust, milthrust, thrust;
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double TAT = (Auxiliary->GetTotalTemperature() - 491.69) * 0.5555556;
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dt = State->Getdt() * Propulsion->GetRate();
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// calculate virtual throttle position (actual +/- lag) based on
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// FCS Throttle value (except when trimming)
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if (dt > 0.0) {
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Running = !Starved;
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ThrottleCmd = FCS->GetThrottleCmd(EngineNumber);
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if ( ThrottleCmd > throttle ) {
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throttle += (dt * delay);
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if (throttle > ThrottleCmd ) throttle = ThrottleCmd;
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}
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else {
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throttle -= (dt * delay * 3.0);
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if (throttle < ThrottleCmd ) throttle = ThrottleCmd;
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}
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}
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else {
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Starved = false;
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throttle = ThrottleCmd = FCS->GetThrottleCmd(EngineNumber);
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}
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idlethrust = MaxMilThrust * ThrustTables[0]->TotalValue();
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milthrust = MaxMilThrust * ThrustTables[1]->TotalValue();
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if (Running) {
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thrust = milthrust * throttle * throttle;
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if (thrust < idlethrust) thrust = idlethrust;
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FuelFlow_pph = thrust * TSFC;
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thrust = thrust * (1.0 - BleedDemand);
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IdleFF = pow(MaxMilThrust, 0.2) * 107.0;
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if (FuelFlow_pph < IdleFF) FuelFlow_pph = IdleFF;
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N1 = IdleN1 + throttle * N1_factor;
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N2 = IdleN2 + throttle * N2_factor;
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EGT_degC = TAT + 363.1 + ThrottleCmd * 357.1;
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OilPressure_psi = N2 * 0.62;
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OilTemp_degK += dt * 1.2;
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if (OilTemp_degK > 366.0) OilTemp_degK = 366.0;
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EPR = 1.0 + thrust/MaxMilThrust;
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NozzlePosition = 1.0 - throttle;
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if (Reversed) thrust = thrust * -0.2;
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}
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else {
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thrust = 0.0;
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FuelFlow_pph = 0.000001;
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N1 -= (dt * 3.0);
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if (N1 < (Translation->Getqbar()/10.0)) N1 = Translation->Getqbar()/10.0;
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N2 -= (dt * 3.5);
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if (N2 < (Translation->Getqbar()/15.0)) N2 = Translation->Getqbar()/15.0;
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EGT_degC -= (dt * 11.7);
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if (EGT_degC < TAT) EGT_degC = TAT;
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OilPressure_psi = N2 * 0.62;
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OilTemp_degK -= (dt * 0.2);
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if (OilTemp_degK < (TAT + 273.0)) OilTemp_degK = (TAT + 273.0);
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EPR = 1.0;
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}
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if (AugMethod == 1) {
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if (throttle > 0.99) {Augmentation = true;}
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else {Augmentation = false;}
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}
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if ((Augmented == 1) && Augmentation) {
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thrust = thrust * ThrustTables[2]->TotalValue();
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FuelFlow_pph = thrust * ATSFC;
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NozzlePosition = 1.0;
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}
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if ((Injected == 1) && Injection)
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thrust = thrust * ThrustTables[3]->TotalValue();
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ConsumeFuel();
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return Thrust = thrust;
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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double FGSimTurbine::CalcFuelNeed(void)
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{
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return FuelFlow_pph /3600 * State->Getdt() * Propulsion->GetRate();
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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void FGSimTurbine::SetDefaults(void)
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{
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Name = "None_Defined";
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MaxMilThrust = 10000.0;
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BypassRatio = 0.0;
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TSFC = 0.8;
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ATSFC = 1.7;
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IdleN1 = 30.0;
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IdleN2 = 60.0;
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MaxN1 = 100.0;
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MaxN2 = 100.0;
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Augmented = 0;
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AugMethod = 0;
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Injected = 0;
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BleedDemand = 0.0;
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throttle = 0.0;
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InletPosition = 1.0;
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NozzlePosition = 1.0;
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Augmentation = false;
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Injection = false;
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Reversed = false;
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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bool FGSimTurbine::Load(FGConfigFile *Eng_cfg)
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{
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int i;
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string token;
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Name = Eng_cfg->GetValue("NAME");
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cout << Name << endl;
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Eng_cfg->GetNextConfigLine();
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*Eng_cfg >> token >> MaxMilThrust;
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*Eng_cfg >> token >> BypassRatio;
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*Eng_cfg >> token >> TSFC;
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*Eng_cfg >> token >> ATSFC;
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*Eng_cfg >> token >> IdleN1;
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*Eng_cfg >> token >> IdleN2;
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*Eng_cfg >> token >> MaxN1;
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*Eng_cfg >> token >> MaxN2;
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*Eng_cfg >> token >> Augmented;
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*Eng_cfg >> token >> AugMethod;
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*Eng_cfg >> token >> Injected;
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i=0;
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while( Eng_cfg->GetValue() != string("/FG_SIMTURBINE") && i < 10){
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ThrustTables.push_back( new FGCoefficient(FDMExec) );
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ThrustTables.back()->Load(Eng_cfg);
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i++;
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}
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// pre-calculations and initializations
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delay= 1.0 / (BypassRatio + 3.0);
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N1_factor = MaxN1 - IdleN1;
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N2_factor = MaxN2 - IdleN2;
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OilTemp_degK = (Auxiliary->GetTotalTemperature() - 491.69) * 0.5555556 + 273.0;
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IdleFF = pow(MaxMilThrust, 0.2) * 107.0; // just an estimate
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AddFeedTank(EngineNumber); // engine[n] feeds from tank[n]
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return true;
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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// The bitmasked value choices are as follows:
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// unset: In this case (the default) JSBSim would only print
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// out the normally expected messages, essentially echoing
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// the config files as they are read. If the environment
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// variable is not set, debug_lvl is set to 1 internally
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// 0: This requests JSBSim not to output any messages
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// whatsoever.
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// 1: This value explicity requests the normal JSBSim
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// startup messages
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// 2: This value asks for a message to be printed out when
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// a class is instantiated
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// 4: When this value is set, a message is displayed when a
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// FGModel object executes its Run() method
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// 8: When this value is set, various runtime state variables
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// are printed out periodically
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// 16: When set various parameters are sanity checked and
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// a message is printed out when they go out of bounds
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void FGSimTurbine::Debug(int from)
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{
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if (debug_lvl <= 0) return;
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if (debug_lvl & 1) { // Standard console startup message output
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if (from == 0) { // Constructor
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}
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}
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if (debug_lvl & 2 ) { // Instantiation/Destruction notification
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if (from == 0) cout << "Instantiated: FGSimTurbine" << endl;
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if (from == 1) cout << "Destroyed: FGSimTurbine" << endl;
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}
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if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
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}
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if (debug_lvl & 8 ) { // Runtime state variables
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}
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if (debug_lvl & 16) { // Sanity checking
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}
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if (debug_lvl & 64) {
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if (from == 0) { // Constructor
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cout << IdSrc << endl;
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cout << IdHdr << endl;
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}
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}
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}
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}
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