130 lines
4.3 KiB
C++
130 lines
4.3 KiB
C++
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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Module: FGRocket.cpp
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Author: Jon S. Berndt
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Date started: 09/12/2000
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Purpose: This module models a rocket engine
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------------- Copyright (C) 2000 Jon S. Berndt (jsb@hal-pc.org) --------------
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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 rocket engine based on
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parameters given in the engine config file for this class
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HISTORY
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--------------------------------------------------------------------------------
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09/12/2000 JSB Created
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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INCLUDES
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
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#include "FGRocket.h"
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static const char *IdSrc = "$Id$";
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static const char *IdHdr = ID_ROCKET;
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extern short debug_lvl;
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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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CLASS IMPLEMENTATION
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
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FGRocket::FGRocket(FGFDMExec* exec, FGConfigFile* Eng_cfg) : FGEngine(exec)
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{
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string token;
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Name = Eng_cfg->GetValue("NAME");
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Eng_cfg->GetNextConfigLine();
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while (Eng_cfg->GetValue() != "/FG_ROCKET") {
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*Eng_cfg >> token;
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if (token == "SHR") *Eng_cfg >> SHR;
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else if (token == "MAX_PC") *Eng_cfg >> maxPC;
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else if (token == "PROP_EFF") *Eng_cfg >> propEff;
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else if (token == "MAXTHROTTLE") *Eng_cfg >> MaxThrottle;
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else if (token == "MINTHROTTLE") *Eng_cfg >> MinThrottle;
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else if (token == "SLFUELFLOWMAX") *Eng_cfg >> SLFuelFlowMax;
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else if (token == "SLOXIFLOWMAX") *Eng_cfg >> SLOxiFlowMax;
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else if (token == "VARIANCE") *Eng_cfg >> Variance;
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else cerr << "Unhandled token in Engine config file: " << token << endl;
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}
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if (debug_lvl > 0) {
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cout << " Engine Name: " << Name << endl;
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cout << " Specific Heat Ratio = " << SHR << endl;
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cout << " Maximum Chamber Pressure = " << maxPC << endl;
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cout << " Propulsive Efficiency = " << propEff << endl;
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cout << " MaxThrottle = " << MaxThrottle << endl;
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cout << " MinThrottle = " << MinThrottle << endl;
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cout << " FuelFlowMax = " << SLFuelFlowMax << endl;
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cout << " OxiFlowMax = " << SLOxiFlowMax << endl;
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cout << " Variance = " << Variance << endl;
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}
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EngineNumber = 0;
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Type = etRocket;
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PC = 0.0;
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kFactor = (2.0*SHR*SHR/(SHR-1.0))*pow(2.0/(SHR+1), (SHR+1)/(SHR-1));
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if (debug_lvl & 2) cout << "Instantiated: FGRocket" << endl;
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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FGRocket::~FGRocket()
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{
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if (debug_lvl & 2) cout << "Destroyed: FGRocket" << endl;
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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float FGRocket::Calculate(float pe)
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{
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float Cf;
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ConsumeFuel();
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Throttle = FCS->GetThrottlePos(EngineNumber);
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if (Throttle < MinThrottle || Starved) {
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PctPower = Thrust = 0.0; // desired thrust
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Flameout = true;
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PC = 0.0;
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} else {
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PctPower = Throttle / MaxThrottle;
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PC = maxPC*PctPower * (1.0 + Variance * ((float)rand()/(float)RAND_MAX - 0.5));
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Cf = sqrt(kFactor*(1 - pow(pe/(PC), (SHR-1)/SHR)));
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Flameout = false;
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}
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return Cf*maxPC*PctPower*propEff;
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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void FGRocket::Debug(void)
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{
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//TODO: Add your source code here
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}
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