Detailed Description

Encapsulates various uncategorized scheduled functions.

Pilot sensed accelerations are calculated here. This is used for the coordinated turn ball instrument. Motion base platforms sometimes use the derivative of pilot sensed accelerations as the driving parameter, rather than straight accelerations.

The theory behind pilot-sensed calculations is presented:

For purposes of discussion and calculation, assume for a minute that the pilot is in space and motionless in inertial space. She will feel no accelerations. If the aircraft begins to accelerate along any axis or axes (without rotating), the pilot will sense those accelerations. If any rotational moment is applied, the pilot will sense an acceleration due to that motion in the amount:

[wdot X R] + [w X (w X R)] Term I Term II

where:

wdot = omegadot, the rotational acceleration rate vector w = omega, the rotational rate vector R = the vector from the aircraft CG to the pilot eyepoint

The sum total of these two terms plus the acceleration of the aircraft body axis gives the acceleration the pilot senses in inertial space. In the presence of a large body such as a planet, a gravity field also provides an accelerating attraction. This acceleration can be transformed from the reference frame of the planet so as to be expressed in the frame of reference of the aircraft. This gravity field accelerating attraction is felt by the pilot as a force on her tushie as she sits in her aircraft on the runway awaiting takeoff clearance.

In JSBSim the acceleration of the body frame in inertial space is given by the F = ma relation. If the vForces vector is divided by the aircraft mass, the acceleration vector is calculated. The term wdot is equivalent to the JSBSim vPQRdot vector, and the w parameter is equivalent to vPQR.

Author: Tony Peden, Jon Berndt

Definition at line 100 of file FGAuxiliary.h.

#include <FGAuxiliary.h>

Inheritance diagram for FGAuxiliary:

Collaboration diagram for FGAuxiliary:

Classes
struct	Inputs

Public Member Functions
	FGAuxiliary (FGFDMExec *Executive)
	Constructor.

	~FGAuxiliary ()
	Destructor.

double	Getadot (int unit) const

double	Getadot (void) const

double	GetAeroPQR (int axis) const

const FGColumnVector3 &	GetAeroPQR (void) const

double	GetAeroUVW (int idx) const

const FGColumnVector3 &	GetAeroUVW (void) const

double	Getalpha (int unit) const

double	Getalpha (void) const

double	Getbdot (int unit) const

double	Getbdot (void) const

double	Getbeta (int unit) const

double	Getbeta (void) const

double	GetDistanceRelativePosition (void) const

double	GetEulerRates (int axis) const

const FGColumnVector3 &	GetEulerRates (void) const

double	GetGamma (int unit) const

double	GetGamma (void) const

double	GetGroundTrack (void) const

double	GetHOverBCG (void) const

double	GetHOverBMAC (void) const

double	GetLatitudeRelativePosition (void) const

const FGLocation &	GetLocationVRP (void) const

double	GetLongitudeRelativePosition (void) const

double	GetMach (void) const
	Gets the Mach number.

double	GetMachU (void) const
	The mach number calculated using the vehicle X axis velocity.

double	GetMagBeta (int unit) const

double	GetMagBeta (void) const

double	GetNcg (int idx) const

const FGColumnVector3 &	GetNcg (void) const

double	GetNlf (void) const

double	GetNpilot (int idx) const

const FGColumnVector3 &	GetNpilot (void) const

const FGColumnVector3 &	GetNwcg (void) const

double	GetNx (void) const
	The longitudinal acceleration in g's of the aircraft center of gravity.

double	GetNy (void) const
	The lateral acceleration in g's of the aircraft center of gravity.

double	GetNz (void) const
	The vertical acceleration in g's of the aircraft center of gravity.

double	GetPilotAccel (int idx) const

const FGColumnVector3 &	GetPilotAccel (void) const

double	Getqbar (void) const

double	GetqbarUV (void) const

double	GetqbarUW (void) const

double	GetReynoldsNumber (void) const

double	GetTAT_C (void) const

const FGMatrix33 &	GetTb2w (void) const
	Calculates and returns the body-to-wind axis transformation matrix.

double	GetTotalPressure (void) const
	Returns the total pressure.

double	GetTotalTemperature (void) const
	Returns the total temperature.

const FGMatrix33 &	GetTw2b (void) const
	Calculates and returns the wind-to-body axis transformation matrix.

double	GetVcalibratedFPS (void) const
	Returns Calibrated airspeed in feet/second.

double	GetVcalibratedKTS (void) const
	Returns Calibrated airspeed in knots.

double	GetVequivalentFPS (void) const
	Returns equivalent airspeed in feet/second.

double	GetVequivalentKTS (void) const
	Returns equivalent airspeed in knots.

double	GetVground (void) const
	Gets the ground speed in feet per second.

double	GetVt (void) const
	Gets the magnitude of total vehicle velocity including wind effects in feet per second.

double	GetVtrueFPS () const
	Returns the true airspeed in feet per second.

double	GetVtrueKTS () const
	Returns the true airspeed in knots.

bool	InitModel (void) override

double	MachFromImpactPressure (double qc, double p) const
	Compute the Mach number from the differential pressure (qc) and the static pressure.

double	MachFromVcalibrated (double vcas, double pressure) const
	Calculate the Mach number from the calibrated airspeed.Based on the formulas in the US Air Force Aircraft Performance Flight Testing Manual (AFFTC-TIH-99-01).

double	PitotTotalPressure (double mach, double pressure) const
	Compute the total pressure in front of the Pitot tube.

bool	Run (bool Holding) override
	Runs the Auxiliary routines; called by the Executive Can pass in a value indicating if the executive is directing the simulation to Hold.

void	SetAeroPQR (const FGColumnVector3 &tt)

double	VcalibratedFromMach (double mach, double pressure) const
	Calculate the calibrated airspeed from the Mach number.

Public Member Functions inherited from FGModel
	FGModel (FGFDMExec *)
	Constructor.

	~FGModel () override
	Destructor.

virtual SGPath	FindFullPathName (const SGPath &path) const

FGFDMExec *	GetExec (void)

const std::string &	GetName (void)

unsigned int	GetRate (void)
	Get the output rate for the model in frames.

bool	InitModel (void) override

virtual bool	Load (Element *el)

void	SetPropertyManager (std::shared_ptr< FGPropertyManager > fgpm)

void	SetRate (unsigned int tt)
	Set the ouput rate for the model in frames.

Public Member Functions inherited from FGModelFunctions
std::string	GetFunctionStrings (const std::string &delimeter) const
	Gets the strings for the current set of functions.

std::string	GetFunctionValues (const std::string &delimeter) const
	Gets the function values.

std::shared_ptr< FGFunction >	GetPreFunction (const std::string &name)
	Get one of the "pre" function.

bool	Load (Element el, FGFDMExec fdmex, std::string prefix="")

void	PostLoad (Element el, FGFDMExec fdmex, std::string prefix="")

void	PreLoad (Element el, FGFDMExec fdmex, std::string prefix="")

void	RunPostFunctions (void)

void	RunPreFunctions (void)

Public Member Functions inherited from FGJSBBase
	FGJSBBase ()
	Constructor for FGJSBBase.

virtual	~FGJSBBase ()
	Destructor for FGJSBBase.

void	disableHighLighting (void)
	Disables highlighting in the console output.

Public Attributes
struct JSBSim::FGAuxiliary::Inputs	in

Additional Inherited Members
Public Types inherited from FGJSBBase
enum	{ eL = 1 , eM , eN }
	Moments L, M, N. More...

enum	{ eP = 1 , eQ , eR }
	Rates P, Q, R. More...

enum	{ eU = 1 , eV , eW }
	Velocities U, V, W. More...

enum	{ eX = 1 , eY , eZ }
	Positions X, Y, Z. More...

enum	{ ePhi = 1 , eTht , ePsi }
	Euler angles Phi, Theta, Psi. More...

enum	{ eDrag = 1 , eSide , eLift }
	Stability axis forces, Drag, Side force, Lift. More...

enum	{ eRoll = 1 , ePitch , eYaw }
	Local frame orientation Roll, Pitch, Yaw. More...

enum	{ eNorth = 1 , eEast , eDown }
	Local frame position North, East, Down. More...

enum	{ eLat = 1 , eLong , eRad }
	Locations Radius, Latitude, Longitude. More...

enum	{ inNone = 0 , inDegrees , inRadians , inMeters , inFeet }
	Conversion specifiers. More...

Static Public Member Functions inherited from FGJSBBase
static const std::string &	GetVersion (void)
	Returns the version number of JSBSim.

static constexpr double	KelvinToFahrenheit (double kelvin)
	Converts from degrees Kelvin to degrees Fahrenheit.

static constexpr double	CelsiusToRankine (double celsius)
	Converts from degrees Celsius to degrees Rankine.

static constexpr double	RankineToCelsius (double rankine)
	Converts from degrees Rankine to degrees Celsius.

static constexpr double	KelvinToRankine (double kelvin)
	Converts from degrees Kelvin to degrees Rankine.

static constexpr double	RankineToKelvin (double rankine)
	Converts from degrees Rankine to degrees Kelvin.

static constexpr double	FahrenheitToCelsius (double fahrenheit)
	Converts from degrees Fahrenheit to degrees Celsius.

static constexpr double	CelsiusToFahrenheit (double celsius)
	Converts from degrees Celsius to degrees Fahrenheit.

static constexpr double	CelsiusToKelvin (double celsius)
	Converts from degrees Celsius to degrees Kelvin.

static constexpr double	KelvinToCelsius (double kelvin)
	Converts from degrees Kelvin to degrees Celsius.

static constexpr double	FeetToMeters (double measure)
	Converts from feet to meters.

static bool	EqualToRoundoff (double a, double b)
	Finite precision comparison.

static bool	EqualToRoundoff (float a, float b)
	Finite precision comparison.

static bool	EqualToRoundoff (float a, double b)
	Finite precision comparison.

static bool	EqualToRoundoff (double a, float b)
	Finite precision comparison.

static constexpr double	Constrain (double min, double value, double max)
	Constrain a value between a minimum and a maximum value.

static constexpr double	sign (double num)

Static Public Attributes inherited from FGJSBBase
static char	highint [5] = {27, '[', '1', 'm', '\0' }
	highlights text

static char	halfint [5] = {27, '[', '2', 'm', '\0' }
	low intensity text

static char	normint [6] = {27, '[', '2', '2', 'm', '\0' }
	normal intensity text

static char	reset [5] = {27, '[', '0', 'm', '\0' }
	resets text properties

static char	underon [5] = {27, '[', '4', 'm', '\0' }
	underlines text

static char	underoff [6] = {27, '[', '2', '4', 'm', '\0' }
	underline off

static char	fgblue [6] = {27, '[', '3', '4', 'm', '\0' }
	blue text

static char	fgcyan [6] = {27, '[', '3', '6', 'm', '\0' }
	cyan text

static char	fgred [6] = {27, '[', '3', '1', 'm', '\0' }
	red text

static char	fggreen [6] = {27, '[', '3', '2', 'm', '\0' }
	green text

static char	fgdef [6] = {27, '[', '3', '9', 'm', '\0' }
	default text

static short	debug_lvl = 1

Protected Member Functions inherited from FGModel
bool	Upload (Element *el, bool preLoad)
	Uploads this model in memory.

Static Protected Member Functions inherited from FGJSBBase
static std::string	CreateIndexedPropertyName (const std::string &Property, int index)

Protected Attributes inherited from FGModel
unsigned int	exe_ctr

FGFDMExec *	FDMExec

std::string	Name

std::shared_ptr< FGPropertyManager >	PropertyManager

unsigned int	rate

Protected Attributes inherited from FGModelFunctions
FGPropertyReader	LocalProperties

std::vector< std::shared_ptr< FGFunction > >	PostFunctions

std::vector< std::shared_ptr< FGFunction > >	PreFunctions

Static Protected Attributes inherited from FGJSBBase
static constexpr double	radtodeg = 180. / M_PI

static constexpr double	degtorad = M_PI / 180.

static constexpr double	hptoftlbssec = 550.0

static constexpr double	psftoinhg = 0.014138

static constexpr double	psftopa = 47.88

static constexpr double	fttom = 0.3048

static constexpr double	ktstofps = 1852./(3600*fttom)

static constexpr double	fpstokts = 1.0 / ktstofps

static constexpr double	inchtoft = 1.0/12.0

static constexpr double	m3toft3 = 1.0/(fttomfttomfttom)

static constexpr double	in3tom3 = inchtoftinchtoftinchtoft/m3toft3

static constexpr double	inhgtopa = 3386.38

static constexpr double	slugtolb = 32.174049
	Note that definition of lbtoslug by the inverse of slugtolb and not to a different constant you can also get from some tables will make lbtoslug*slugtolb == 1 up to the magnitude of roundoff.

static constexpr double	lbtoslug = 1.0/slugtolb

static constexpr double	kgtolb = 2.20462

static constexpr double	kgtoslug = 0.06852168

static const std::string	needed_cfg_version = "2.0"

static const std::string	JSBSim_version = JSBSIM_VERSION " " __DATE__ " " __TIME__

Constructor & Destructor Documentation

◆ FGAuxiliary()

FGAuxiliary ( FGFDMExec * Executive )

explicit

Constructor.

Parameters

Executive a pointer to the parent executive object

Definition at line 61 of file FGAuxiliary.cpp.

                                         : FGModel(fdmex)
{
  Name = "FGAuxiliary";
  pt = FGAtmosphere::StdDaySLpressure;     // ISA SL pressure
  tat = FGAtmosphere::StdDaySLtemperature; // ISA SL temperature
  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;
  psigt = 0.0;
  hoverbmac = hoverbcg = 0.0;
  Re = 0.0;
  Nx = Ny = Nz = 0.0;
 
  vPilotAccel.InitMatrix();
  vPilotAccelN.InitMatrix();
  vAeroUVW.InitMatrix();
  vAeroPQR.InitMatrix();
  vMachUVW.InitMatrix();
  vEulerRates.InitMatrix();
 
  bind();
 
  Debug(0);
}

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◆ ~FGAuxiliary()

~FGAuxiliary ( )

Destructor.

Definition at line 124 of file FGAuxiliary.cpp.

{
  Debug(1);
}

Member Function Documentation

◆ Getadot() [1/2]

double Getadot ( int unit ) const

inline

Definition at line 215 of file FGAuxiliary.h.

215 { if (unit == inDegrees) return adot*radtodeg;

216 else return BadUnits(); }

◆ Getadot() [2/2]

double Getadot ( void ) const

inline

Definition at line 207 of file FGAuxiliary.h.

207{ return adot; }

◆ GetAeroPQR() [1/2]

double GetAeroPQR ( int axis ) const

inline

Definition at line 191 of file FGAuxiliary.h.

191{ return vAeroPQR(axis); }

◆ GetAeroPQR() [2/2]

const FGColumnVector3 & GetAeroPQR ( void ) const

inline

Definition at line 199 of file FGAuxiliary.h.

199{ return vAeroPQR; }

◆ GetAeroUVW() [1/2]

double GetAeroUVW ( int idx ) const

inline

Definition at line 204 of file FGAuxiliary.h.

204{ return vAeroUVW(idx); }

◆ GetAeroUVW() [2/2]

const FGColumnVector3 & GetAeroUVW ( void ) const

inline

Definition at line 201 of file FGAuxiliary.h.

201{ return vAeroUVW; }

◆ Getalpha() [1/2]

double Getalpha ( int unit ) const

inline

Definition at line 211 of file FGAuxiliary.h.

211 { if (unit == inDegrees) return alpha*radtodeg;

212 else return BadUnits(); }

◆ Getalpha() [2/2]

double Getalpha ( void ) const

inline

Definition at line 205 of file FGAuxiliary.h.

205{ return alpha; }

◆ Getbdot() [1/2]

double Getbdot ( int unit ) const

inline

Definition at line 217 of file FGAuxiliary.h.

217 { if (unit == inDegrees) return bdot*radtodeg;

218 else return BadUnits(); }

◆ Getbdot() [2/2]

double Getbdot ( void ) const

inline

Definition at line 208 of file FGAuxiliary.h.

208{ return bdot; }

◆ Getbeta() [1/2]

double Getbeta ( int unit ) const

inline

Definition at line 213 of file FGAuxiliary.h.

213 { if (unit == inDegrees) return beta*radtodeg;

214 else return BadUnits(); }

◆ Getbeta() [2/2]

double Getbeta ( void ) const

inline

Definition at line 206 of file FGAuxiliary.h.

206{ return beta; }

◆ GetDistanceRelativePosition()

double GetDistanceRelativePosition ( void ) const

Definition at line 370 of file FGAuxiliary.cpp.

{
  auto ic = FDMExec->GetIC();
  return in.vLocation.GetDistanceTo(ic->GetLongitudeRadIC(),
                                    ic->GetGeodLatitudeRadIC())* fttom;
}

◆ GetEulerRates() [1/2]

double GetEulerRates ( int axis ) const

inline

Definition at line 192 of file FGAuxiliary.h.

192{ return vEulerRates(axis); }

◆ GetEulerRates() [2/2]

const FGColumnVector3 & GetEulerRates ( void ) const

inline

Definition at line 200 of file FGAuxiliary.h.

200{ return vEulerRates; }

◆ GetGamma() [1/2]

double GetGamma ( int unit ) const

inline

Definition at line 270 of file FGAuxiliary.h.

                                  {
    if (unit == inDegrees) return gamma*radtodeg;
    else return BadUnits();
  }

◆ GetGamma() [2/2]

double GetGamma ( void ) const

inline

Definition at line 267 of file FGAuxiliary.h.

267{ return gamma; }

◆ GetGroundTrack()

double GetGroundTrack ( void ) const

inline

Definition at line 268 of file FGAuxiliary.h.

268{ return psigt; }

◆ GetHOverBCG()

double GetHOverBCG ( void ) const

inline

Definition at line 264 of file FGAuxiliary.h.

264{ return hoverbcg; }

◆ GetHOverBMAC()

double GetHOverBMAC ( void ) const

inline

Definition at line 265 of file FGAuxiliary.h.

265{ return hoverbmac; }

◆ GetLatitudeRelativePosition()

double GetLatitudeRelativePosition ( void ) const

Definition at line 362 of file FGAuxiliary.cpp.

{
  return in.vLocation.GetDistanceTo(in.vLocation.GetLongitude(),
                                    FDMExec->GetIC()->GetGeodLatitudeRadIC())* fttom;
}

◆ GetLocationVRP()

const FGLocation & GetLocationVRP ( void ) const

inline

Definition at line 202 of file FGAuxiliary.h.

202{ return vLocationVRP; }

◆ GetLongitudeRelativePosition()

double GetLongitudeRelativePosition ( void ) const

Definition at line 354 of file FGAuxiliary.cpp.

{
  return in.vLocation.GetDistanceTo(FDMExec->GetIC()->GetLongitudeRadIC(),
                                    in.vLocation.GetGeodLatitudeRad())* fttom;
}

◆ GetMach()

double GetMach ( void ) const

inline

Gets the Mach number.

Definition at line 248 of file FGAuxiliary.h.

248{ return Mach; }

◆ GetMachU()

double GetMachU ( void ) const

inline

The mach number calculated using the vehicle X axis velocity.

Definition at line 251 of file FGAuxiliary.h.

251{ return MachU; }

◆ GetMagBeta() [1/2]

double GetMagBeta ( int unit ) const

inline

Definition at line 219 of file FGAuxiliary.h.

219 { if (unit == inDegrees) return fabs(beta)*radtodeg;

220 else return BadUnits(); }

◆ GetMagBeta() [2/2]

double GetMagBeta ( void ) const

inline

Definition at line 209 of file FGAuxiliary.h.

209{ return fabs(beta); }

◆ GetNcg() [1/2]

double GetNcg ( int idx ) const

inline

Definition at line 197 of file FGAuxiliary.h.

197{ return vNcg(idx); }

◆ GetNcg() [2/2]

const FGColumnVector3 & GetNcg ( void ) const

inline

Definition at line 196 of file FGAuxiliary.h.

196{ return vNcg; }

◆ GetNlf()

double GetNlf ( void ) const

Definition at line 344 of file FGAuxiliary.cpp.

{
  if (in.Mass != 0)
    return (in.vFw(3))/(in.Mass*slugtolb);
  else
    return 0.;
}

◆ GetNpilot() [1/2]

double GetNpilot ( int idx ) const

inline

Definition at line 190 of file FGAuxiliary.h.

190{ return vPilotAccelN(idx); }

◆ GetNpilot() [2/2]

const FGColumnVector3 & GetNpilot ( void ) const

inline

Definition at line 195 of file FGAuxiliary.h.

195{ return vPilotAccelN; }

◆ GetNwcg()

const FGColumnVector3 & GetNwcg ( void ) const

inline

Definition at line 262 of file FGAuxiliary.h.

262{ return vNwcg; }

◆ GetNx()

double GetNx ( void ) const

inline

The longitudinal acceleration in g's of the aircraft center of gravity.

Definition at line 254 of file FGAuxiliary.h.

254{ return Nx; }

◆ GetNy()

double GetNy ( void ) const

inline

The lateral acceleration in g's of the aircraft center of gravity.

Definition at line 257 of file FGAuxiliary.h.

257{ return Ny; }

◆ GetNz()

double GetNz ( void ) const

inline

The vertical acceleration in g's of the aircraft center of gravity.

Definition at line 260 of file FGAuxiliary.h.

260{ return Nz; }

◆ GetPilotAccel() [1/2]

double GetPilotAccel ( int idx ) const

inline

Definition at line 189 of file FGAuxiliary.h.

189{ return vPilotAccel(idx); }

◆ GetPilotAccel() [2/2]

const FGColumnVector3 & GetPilotAccel ( void ) const

inline

Definition at line 194 of file FGAuxiliary.h.

194{ return vPilotAccel; }

◆ Getqbar()

double Getqbar ( void ) const

inline

Definition at line 232 of file FGAuxiliary.h.

232{ return qbar; }

◆ GetqbarUV()

double GetqbarUV ( void ) const

inline

Definition at line 234 of file FGAuxiliary.h.

234{ return qbarUV; }

◆ GetqbarUW()

double GetqbarUW ( void ) const

inline

Definition at line 233 of file FGAuxiliary.h.

233{ return qbarUW; }

◆ GetReynoldsNumber()

double GetReynoldsNumber ( void ) const

inline

Definition at line 235 of file FGAuxiliary.h.

235{ return Re; }

◆ GetTAT_C()

double GetTAT_C ( void ) const

inline

Definition at line 187 of file FGAuxiliary.h.

187{ return tatc; }

◆ GetTb2w()

const FGMatrix33 & GetTb2w ( void ) const

inline

Calculates and returns the body-to-wind axis transformation matrix.

Returns: a reference to the wind-to-body transformation matrix.

Definition at line 230 of file FGAuxiliary.h.

230{ return mTb2w; }

◆ GetTotalPressure()

double GetTotalPressure ( void ) const

inline

Returns the total pressure.

Total pressure is freestream total pressure for subsonic only. For supersonic it is the 1D total pressure behind a normal shock.

Definition at line 176 of file FGAuxiliary.h.

176{ return pt; }

◆ GetTotalTemperature()

double GetTotalTemperature ( void ) const

inline

Returns the total temperature.

The total temperature ("tat", isentropic flow) is calculated:

tat = in.Temperature*(1 + 0.2*Mach*Mach)

(where "in.Temperature" is standard temperature calculated by the atmosphere model)

Definition at line 186 of file FGAuxiliary.h.

186{ return tat; }

◆ GetTw2b()

const FGMatrix33 & GetTw2b ( void ) const

inline

Calculates and returns the wind-to-body axis transformation matrix.

Returns: a reference to the wind-to-body transformation matrix.

Definition at line 225 of file FGAuxiliary.h.

225{ return mTw2b; }

◆ GetVcalibratedFPS()

double GetVcalibratedFPS ( void ) const

inline

Returns Calibrated airspeed in feet/second.

Definition at line 160 of file FGAuxiliary.h.

160{ return vcas; }

◆ GetVcalibratedKTS()

double GetVcalibratedKTS ( void ) const

inline

Returns Calibrated airspeed in knots.

Definition at line 162 of file FGAuxiliary.h.

162{ return vcas*fpstokts; }

◆ GetVequivalentFPS()

double GetVequivalentFPS ( void ) const

inline

Returns equivalent airspeed in feet/second.

Definition at line 164 of file FGAuxiliary.h.

164{ return veas; }

◆ GetVequivalentKTS()

double GetVequivalentKTS ( void ) const

inline

Returns equivalent airspeed in knots.

Definition at line 166 of file FGAuxiliary.h.

166{ return veas*fpstokts; }

◆ GetVground()

double GetVground ( void ) const

inline

Gets the ground speed in feet per second.

The magnitude is the square root of the sum of the squares (RSS) of the vehicle north and east velocity components.

Returns: The magnitude of the vehicle velocity in the horizontal plane.

Definition at line 245 of file FGAuxiliary.h.

245{ return Vground; }

◆ GetVt()

double GetVt ( void ) const

inline

Gets the magnitude of total vehicle velocity including wind effects in feet per second.

Definition at line 239 of file FGAuxiliary.h.

239{ return Vt; }

◆ GetVtrueFPS()

double GetVtrueFPS ( ) const

inline

Returns the true airspeed in feet per second.

Definition at line 168 of file FGAuxiliary.h.

168{ return Vt; }

◆ GetVtrueKTS()

double GetVtrueKTS ( ) const

inline

Returns the true airspeed in knots.

Definition at line 170 of file FGAuxiliary.h.

170{ return Vt * fpstokts; }

◆ InitModel()

bool InitModel ( void )

overridevirtual

Reimplemented from FGModelFunctions.

Definition at line 93 of file FGAuxiliary.cpp.

{
  if (!FGModel::InitModel()) return false;
 
  pt = in.Pressure;
  tat = in.Temperature;
  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;
  psigt = 0.0;
  hoverbmac = hoverbcg = 0.0;
  Re = 0.0;
  Nz = Ny = 0.0;
 
  vPilotAccel.InitMatrix();
  vPilotAccelN.InitMatrix();
  vAeroUVW.InitMatrix();
  vAeroPQR.InitMatrix();
  vMachUVW.InitMatrix();
  vEulerRates.InitMatrix();
 
  return true;
}

◆ MachFromImpactPressure()

double MachFromImpactPressure	(	double	qc,
		double	p
	)		const

Compute the Mach number from the differential pressure (qc) and the static pressure.

Based on the formulas in the US Air Force Aircraft Performance Flight Testing Manual (AFFTC-TIH-99-01).

Parameters

qc	The differential/impact pressure
pressure	Pressure in psf

Returns: The Mach number

Definition at line 267 of file FGAuxiliary.cpp.

{
  constexpr double SHRatio = FGAtmosphere::SHRatio;
  constexpr double a = 2.0/(SHRatio-1.0);
  constexpr double b = (SHRatio-1.0)/SHRatio;
  constexpr double c = 2.0/b;
  constexpr double d = 0.5*a;
  const double coeff = pow(0.5*(SHRatio+1.0), -0.25*c)
                     * pow(0.5*(SHRatio+1.0)/SHRatio, -0.5*d);
 
  double A = qc / pressure + 1;
  double M = sqrt(a*(pow(A, b) - 1.0));  // Equation (4.12)
 
  if (M > 1.0)
    for (unsigned int i = 0; i<10; i++)
      M = coeff*sqrt(A*pow(1 - 1.0 / (c*M*M), d));  // Equation (4.17)
 
  return M;
}

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◆ MachFromVcalibrated()

double MachFromVcalibrated	(	double	vcas,
		double	pressure
	)		const

Calculate the Mach number from the calibrated airspeed.Based on the formulas in the US Air Force Aircraft Performance Flight Testing Manual (AFFTC-TIH-99-01).

Parameters

vcas	The calibrated airspeed (CAS) in ft/s
pressure	Pressure in psf

Returns: The Mach number

Definition at line 297 of file FGAuxiliary.cpp.

{
  constexpr double StdDaySLpressure = FGAtmosphere::StdDaySLpressure;
  double qc = PitotTotalPressure(vcas / in.StdDaySLsoundspeed, StdDaySLpressure) - StdDaySLpressure;
  return MachFromImpactPressure(qc, pressure);
}

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◆ PitotTotalPressure()

double PitotTotalPressure	(	double	mach,
		double	pressure
	)		const

Compute the total pressure in front of the Pitot tube.

It uses the Rayleigh formula for supersonic speeds (See "Introduction to Aerodynamics of a Compressible Fluid - H.W. Liepmann, A.E. Puckett - Wiley & sons (1947)" §5.4 pp 75-80)

Parameters

mach	The Mach number
pressure	Pressure in psf

Returns: The total pressure in front of the Pitot tube in psf

Definition at line 230 of file FGAuxiliary.cpp.

{
  constexpr double SHRatio = FGAtmosphere::SHRatio;
  constexpr double a = (SHRatio-1.0) / 2.0;
  constexpr double b = SHRatio / (SHRatio-1.0);
  constexpr double c = 2.0*b;
  constexpr double d = 1.0 / (SHRatio-1.0);
  const double coeff = pow(0.5*(SHRatio+1.0), b)
                     * pow((SHRatio+1.0)/(SHRatio-1.0), d);
 
  if (mach < 0) return pressure;
  if (mach < 1)    //calculate total pressure assuming isentropic flow
    return pressure*pow((1.0 + a*mach*mach), b);
  else {
    // Shock in front of pitot tube, we'll assume its normal and use the
    // Rayleigh Pitot Tube Formula, i.e. the ratio of total pressure behind the
    // shock to the static pressure in front of the normal shock assumption
    // should not be a bad one -- most supersonic aircraft place the pitot probe
    // out front so that it is the forward most point on the aircraft.
    // The real shock would, of course, take on something like the shape of a
    // rounded-off cone but, here again, the assumption should be good since the
    // opening of the pitot probe is very small and, therefore, the effects of
    // the shock curvature should be small as well. AFAIK, this approach is
    // fairly well accepted within the aerospace community
 
    // The denominator below is zero for Mach ~ 0.38, for which
    // we'll never be here, so we're safe
 
    return pressure*coeff*pow(mach, c)/pow(c*mach*mach-1.0, d);
  }
}

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◆ Run()

bool Run ( bool Holding )

overridevirtual

Runs the Auxiliary routines; called by the Executive Can pass in a value indicating if the executive is directing the simulation to Hold.

Parameters

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.

Returns: false if no error

Reimplemented from FGModel.

Definition at line 131 of file FGAuxiliary.cpp.

{
  if (FGModel::Run(Holding)) return true; // return true if error returned from base class
  if (Holding) return false;
 
  // Rotation
 
  vEulerRates(eTht) = in.vPQR(eQ)*in.CosPhi - in.vPQR(eR)*in.SinPhi;
  if (in.CosTht != 0.0) {
    vEulerRates(ePsi) = (in.vPQR(eQ)*in.SinPhi + in.vPQR(eR)*in.CosPhi)/in.CosTht;
    vEulerRates(ePhi) = in.vPQR(eP) + vEulerRates(ePsi)*in.SinTht;
  }
 
  // Combine the wind speed with aircraft speed to obtain wind relative speed
  vAeroPQR = in.vPQR - in.TurbPQR;
  vAeroUVW = in.vUVW - in.Tl2b * in.TotalWindNED;
 
  alpha = beta = adot = bdot = 0;
  double AeroU2 = vAeroUVW(eU)*vAeroUVW(eU);
  double AeroV2 = vAeroUVW(eV)*vAeroUVW(eV);
  double AeroW2 = vAeroUVW(eW)*vAeroUVW(eW);
  double mUW = AeroU2 + AeroW2;
 
  double Vt2 = mUW + AeroV2;
  Vt = sqrt(Vt2);
 
  if ( Vt > 0.001 ) {
    beta = atan2(vAeroUVW(eV), sqrt(mUW));
 
    if ( mUW >= 1E-6 ) {
      alpha = atan2(vAeroUVW(eW), vAeroUVW(eU));
      double Vtdot = (vAeroUVW(eU)*in.vUVWdot(eU) + vAeroUVW(eV)*in.vUVWdot(eV) + vAeroUVW(eW)*in.vUVWdot(eW))/Vt;
      adot = (vAeroUVW(eU)*in.vUVWdot(eW) - vAeroUVW(eW)*in.vUVWdot(eU))/mUW;
      bdot = (in.vUVWdot(eV)*Vt - vAeroUVW(eV)*Vtdot)/(Vt*sqrt(mUW));
    }
  }
 
  UpdateWindMatrices();
 
  Re = Vt * in.Wingchord / in.KinematicViscosity;
 
  double densityD2 = 0.5*in.Density;
 
  qbar = densityD2 * Vt2;
  qbarUW = densityD2 * (mUW);
  qbarUV = densityD2 * (AeroU2 + AeroV2);
  Mach = Vt / in.SoundSpeed;
  MachU = vMachUVW(eU) = vAeroUVW(eU) / in.SoundSpeed;
  vMachUVW(eV) = vAeroUVW(eV) / in.SoundSpeed;
  vMachUVW(eW) = vAeroUVW(eW) / in.SoundSpeed;
 
  // Position
 
  Vground = sqrt( in.vVel(eNorth)*in.vVel(eNorth) + in.vVel(eEast)*in.vVel(eEast) );
 
  psigt = atan2(in.vVel(eEast), in.vVel(eNorth));
  if (psigt < 0.0) psigt += 2*M_PI;
  gamma = atan2(-in.vVel(eDown), Vground);
 
  tat = in.Temperature*(1 + 0.2*Mach*Mach); // Total Temperature, isentropic flow
  tatc = RankineToCelsius(tat);
 
  pt = PitotTotalPressure(Mach, in.Pressure);
 
  if (abs(Mach) > 0.0) {
    vcas = VcalibratedFromMach(Mach, in.Pressure);
    veas = sqrt(2 * qbar / FGAtmosphere::StdDaySLdensity);
  }
  else
    vcas = veas = 0.0;
 
  vPilotAccel.InitMatrix();
  vNcg = in.vBodyAccel/in.StandardGravity;
  // Nz is Acceleration in "g's", along normal axis (-Z body axis)
  Nz = -vNcg(eZ);
  Ny =  vNcg(eY);
  Nx =  vNcg(eX);
  vPilotAccel = in.vBodyAccel + in.vPQRidot * in.ToEyePt;
  vPilotAccel += in.vPQRi * (in.vPQRi * in.ToEyePt);
 
  vNwcg = mTb2w * vNcg;
  vNwcg(eZ) = 1.0 - vNwcg(eZ);
 
  vPilotAccelN = vPilotAccel / in.StandardGravity;
 
  // VRP computation
  vLocationVRP = in.vLocation.LocalToLocation( in.Tb2l * in.VRPBody );
 
  // Recompute some derived values now that we know the dependent parameters values ...
  hoverbcg = in.DistanceAGL / in.Wingspan;
 
  FGColumnVector3 vMac = in.Tb2l * in.RPBody;
  hoverbmac = (in.DistanceAGL - vMac(3)) / in.Wingspan;
 
  return false;
}

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◆ SetAeroPQR()

void SetAeroPQR ( const FGColumnVector3 & tt )

inline

Definition at line 279 of file FGAuxiliary.h.

279{ vAeroPQR = tt; }

◆ VcalibratedFromMach()

double VcalibratedFromMach	(	double	mach,
		double	pressure
	)		const

Calculate the calibrated airspeed from the Mach number.

Based on the formulas in the US Air Force Aircraft Performance Flight Testing Manual (AFFTC-TIH-99-01).

Parameters

mach	The Mach number
pressure	Pressure in psf

Returns: The calibrated airspeed (CAS) in ft/s

Definition at line 289 of file FGAuxiliary.cpp.

{
  double qc = PitotTotalPressure(mach, pressure) - pressure;
  return in.StdDaySLsoundspeed * MachFromImpactPressure(qc, FGAtmosphere::StdDaySLpressure);
}

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The documentation for this class was generated from the following files:

Detailed Description

Classes

Public Member Functions

Public Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ FGAuxiliary()

◆ ~FGAuxiliary()

Member Function Documentation

◆ Getadot() [1/2]

◆ Getadot() [2/2]

◆ GetAeroPQR() [1/2]

◆ GetAeroPQR() [2/2]

◆ GetAeroUVW() [1/2]

◆ GetAeroUVW() [2/2]

◆ Getalpha() [1/2]

◆ Getalpha() [2/2]

◆ Getbdot() [1/2]

◆ Getbdot() [2/2]

◆ Getbeta() [1/2]

◆ Getbeta() [2/2]

◆ GetDistanceRelativePosition()

◆ GetEulerRates() [1/2]

◆ GetEulerRates() [2/2]

◆ GetGamma() [1/2]

◆ GetGamma() [2/2]

◆ GetGroundTrack()

◆ GetHOverBCG()

◆ GetHOverBMAC()

◆ GetLatitudeRelativePosition()

◆ GetLocationVRP()

◆ GetLongitudeRelativePosition()

◆ GetMach()

◆ GetMachU()

◆ GetMagBeta() [1/2]

◆ GetMagBeta() [2/2]

◆ GetNcg() [1/2]

◆ GetNcg() [2/2]

◆ GetNlf()

◆ GetNpilot() [1/2]

◆ GetNpilot() [2/2]

◆ GetNwcg()

◆ GetNx()

◆ GetNy()

◆ GetNz()

◆ GetPilotAccel() [1/2]

◆ GetPilotAccel() [2/2]

◆ Getqbar()

◆ GetqbarUV()

◆ GetqbarUW()

◆ GetReynoldsNumber()

◆ GetTAT_C()

◆ GetTb2w()

◆ GetTotalPressure()

◆ GetTotalTemperature()

◆ GetTw2b()

◆ GetVcalibratedFPS()

◆ GetVcalibratedKTS()

◆ GetVequivalentFPS()

◆ GetVequivalentKTS()

◆ GetVground()

◆ GetVt()

◆ GetVtrueFPS()

◆ GetVtrueKTS()

◆ InitModel()

◆ MachFromImpactPressure()

◆ MachFromVcalibrated()

◆ PitotTotalPressure()

◆ Run()

◆ SetAeroPQR()

◆ VcalibratedFromMach()