1 /*******************************************************************************
3 Module: FGAuxiliary.cpp
6 Purpose: Calculates additional parameters needed by the visual system, etc.
9 ------------- Copyright (C) 1999 Jon S. Berndt (jsb@hal-pc.org) -------------
11 This program is free software; you can redistribute it and/or modify it under
12 the terms of the GNU General Public License as published by the Free Software
13 Foundation; either version 2 of the License, or (at your option) any later
16 This program is distributed in the hope that it will be useful, but WITHOUT
17 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
18 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
21 You should have received a copy of the GNU General Public License along with
22 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
23 Place - Suite 330, Boston, MA 02111-1307, USA.
25 Further information about the GNU General Public License can also be found on
26 the world wide web at http://www.gnu.org.
28 FUNCTIONAL DESCRIPTION
29 --------------------------------------------------------------------------------
30 This class calculates various auxiliary parameters, mostly used by the visual
34 Anderson, John D. "Introduction to Flight", 3rd Edition, McGraw-Hill, 1989
37 --------------------------------------------------------------------------------
40 ********************************************************************************
42 *******************************************************************************/
44 #include "FGAuxiliary.h"
45 #include "FGTranslation.h"
46 #include "FGRotation.h"
47 #include "FGAtmosphere.h"
49 #include "FGFDMExec.h"
51 #include "FGAircraft.h"
52 #include "FGPosition.h"
55 /*******************************************************************************
56 ************************************ CODE **************************************
57 *******************************************************************************/
59 FGAuxiliary::FGAuxiliary(FGFDMExec* fdmex) : FGModel(fdmex)
62 vcas=veas=mach=qbar=pt=0;
67 FGAuxiliary::~FGAuxiliary()
72 bool FGAuxiliary::Run()
75 if (!FGModel::Run()) {
78 //calculate total pressure assuming isentropic flow
79 pt=p*pow((1 + 0.2*mach*mach),3.5);
82 // shock in front of pitot tube, we'll assume its normal and use
83 // the Rayleigh Pitot Tube Formula, i.e. the ratio of total
84 // pressure behind the shock to the static pressure in front
85 B=5.76*mach*mach/(5.6*mach*mach - 0.8);
86 // The denominator above is zero for Mach ~ 0.38, for which
87 // we'll never be here, so we're safe
88 D=(2.8*mach*mach-0.4)*0.4167;
91 A=pow(((pt-p)/psl+1),0.28571);
92 vcas=sqrt(7*psl/rhosl*(A-1));
93 veas=sqrt(2*qbar/rhosl);
99 void FGAuxiliary::GetState(void)
101 qbar=State->Getqbar();
102 mach=State->GetMach();
103 p=Atmosphere->GetPressure();
104 rhosl=Atmosphere->GetDensity(0);
105 psl=Atmosphere->GetPressure(0);
108 void FGAuxiliary::PutState(void){}