Detailed Description

Models a helicopter rotor.

Configuration File Format

<rotor name="{string}">
  <diameter unit="{LENGTH}"> {number} </diameter>
  <numblades> {number} </numblades>
  <gearratio> {number} </gearratio>
  <nominalrpm> {number} </nominalrpm>
  <minrpm> {number} </minrpm>
  <maxrpm> {number} </maxrpm>
  <chord unit="{LENGTH}"> {number} </chord>
  <liftcurveslope Xunit="1/RAD"> {number} </liftcurveslope>
  <twist unit="{ANGLE}"> {number} </twist>
  <hingeoffset unit="{LENGTH}"> {number} </hingeoffset>
  <flappingmoment unit="{MOMENT}"> {number} </flappingmoment>
  <massmoment Xunit="SLUG*FT"> {number} </massmoment>
  <polarmoment unit="{MOMENT}"> {number} </polarmoment>
  <inflowlag> {number} </inflowlag>
  <tiplossfactor> {number} </tiplossfactor>
  <maxbrakepower unit="{POWER}"> {number} </maxbrakepower>
  <gearloss unit="{POWER}"> {number} </gearloss>
  <gearmoment unit="{MOMENT}"> {number} </gearmoment>
 
  <controlmap> {MAIN|TAIL|TANDEM} </controlmap>
  <ExternalRPM> {number} </ExternalRPM>
 
  <groundeffectexp> {number} </groundeffectexp>
  <groundeffectshift unit="{LENGTH}"> {number} </groundeffectshift>
 
</rotor>
 
//  LENGTH means any of the supported units, same for ANGLE and MOMENT.
//  Xunit-attributes are a hint for currently unsupported units, so
//  values must be provided accordingly.

Configuration Parameters:

Brief description and the symbol frequently found in the literature.

    <diameter>           - Rotor disk diameter (2x R).
    <numblades>          - Number of blades (b).
    <gearratio>          - Ratio of (engine rpm) / (rotor rpm), usually > 1.
    <nominalrpm>         - RPM at which the rotor usally operates.
    <minrpm>             - Lowest RPM used in the model, optional and defaults to 1.
    <maxrpm>             - Largest RPM used in the model, optional and defaults to 2 x nominalrpm.
    <chord>              - Blade chord, (c).
    <liftcurveslope>     - Slope of curve of section lift against section angle of attack,
                             per rad (a).
    <twist>              - Blade twist from root to tip, (theta_1).
    <hingeoffset>        - Rotor flapping-hinge offset (e).
    <flappingmoment>     - Flapping moment of inertia (I_b).
    <massmoment>         - Blade mass moment. Mass of a single blade times the blade's
                             cg-distance from the hub, optional.
    <polarmoment>        - Moment of inertia for the whole rotor disk, optional.
    <inflowlag>          - Rotor inflow time constant, sec. Smaller values yield to quicker
                              responses (typical values for main rotor: 0.1 - 0.2 s).
    <tiplossfactor>      - Tip-loss factor. The Blade fraction that produces lift.
                              Value usually ranges between 0.95 - 1.0, optional (B).

    <maxbrakepower>      - Rotor brake, 20-30 hp should work for a mid size helicopter.
    <gearloss>           - Friction in gear, 0.2% to 3% of the engine power, optional (see notes).
    <gearmoment>         - Approximation for the moment of inertia of the gear (and engine),
                              defaults to 0.1 * polarmoment, optional.

    <controlmap>         - Defines the control inputs used (see notes).

    <ExternalRPM>        - Links the rotor to another rotor, or an user controllable property.

    Experimental properties

    <groundeffectexp>    - Exponent for ground effect approximation. Values usually range from 0.04
                            for large rotors to 0.1 for smaller ones. As a rule of thumb the effect
                            vanishes at a height 2-3 times the rotor diameter.
                              formula used: exp ( - groundeffectexp * (height+groundeffectshift) )
                            Omitting or setting to 0.0 disables the effect calculation.
    <groundeffectshift>  - Further adjustment of ground effect, approx. hub height or slightly above
                            (This lessens the influence of the ground effect).

Notes:

- Controls -

The behavior of the rotor is controlled/influenced by following inputs.

The power provided by the engine. This is handled by the regular engine controls.
The collective control input. This is read from the fdm property propulsion/engine[x]/collective-ctrl-rad. See below for tail rotor
The lateral cyclic input. Read from propulsion/engine[x]/lateral-ctrl-rad.
The longitudinal cyclic input. Read from propulsion/engine[x]/longitudinal-ctrl-rad.
The tail rotor collective (aka antitorque, aka pedal) control input. Read from propulsion/engine[x]/antitorque-ctrl-rad or propulsion/engine[x]/tail-collective-ctrl-rad.

- Tail/tandem rotor -

Providing <ExternalRPM> 0 </ExternalRPM> the tail rotor's RPM is linked to to the main (=first, =0) rotor, and specifing <controlmap> TAIL </controlmap> tells this rotor to read the collective input from propulsion/engine[1]/antitorque-ctrl-rad (The TAIL-map ignores lateral and longitudinal input). The rotor needs to be attached to a dummy engine, e.g. an 1HP electrical engine. A tandem rotor is setup analogous.

- Sense -

The 'sense' parameter from the thruster is interpreted as follows, sense=1 means counter clockwise rotation of the main rotor, as viewed from above. This is as a far as I know more popular than clockwise rotation, which is defined by setting sense to -1. Concerning coaxial designs - by setting 'sense' to zero, a Kamov-style rotor is modeled (i.e. the rotor produces no torque).

- Engine issues -

In order to keep the rotor/engine speed constant, use of a RPM-Governor system is encouraged (see examples).

In case the model requires the manual use of a clutch the <gearloss> property might need attention.

Electrical: here the gear-loss should be rather large to keep the engine controllable when the clutch is open (although full throttle might still make it spin away).
Piston: this engine model already has some internal friction loss and also looses power if it spins too high. Here the gear-loss could be set to 0.25% of the engine power (which is also the approximated default).
Turboprop: Here the default value might be a bit too small. Also it's advisable to adjust the power table for rpm values that are far beyond the nominal value.

- Scaling the ground effect -

The property propulsion/engine[x]/groundeffect-scale-norm allows fdm based scaling of the ground effect influence. For instance the effect vanishes at speeds above approx. 50kts, or one likes to land on a 'perforated' helipad.

- Development hints -

Setting <ExternalRPM> -1 </ExternalRPM> the rotor's RPM is controlled by the propulsion/engine[x]/x-rpm-dict property. This feature can be useful when developing a FDM.

References:

<dl>    
<dt>/SH79/</dt><dd>Shaugnessy, J. D., Deaux, Thomas N., and Yenni, Kenneth R.,
          "Development and Validation of a Piloted Simulation of a
          Helicopter and External Sling Load",  NASA TP-1285, 1979.</dd>
<dt>/BA41/</dt><dd>Bailey,F.J.,Jr., "A Simplified Theoretical Method of Determining
          the Characteristics of a Lifting Rotor in Forward Flight", NACA Rep.716, 1941.</dd>
<dt>/AM50/</dt><dd>Amer, Kenneth B.,"Theory of Helicopter Damping in Pitch or Roll and a
          Comparison With Flight Measurements", NACA TN-2136, 1950.</dd>
<dt>/TA77/</dt><dd>Talbot, Peter D., Corliss, Lloyd D., "A Mathematical Force and Moment
          Model of a UH-1H Helicopter for Flight Dynamics Simulations", NASA TM-73,254, 1977.</dd>
<dt>/GE49/</dt><dd>Gessow, Alfred, Amer, Kenneth B. "An Introduction to the Physical 
          Aspects of Helicopter Stability", NACA TN-1982, 1949.</dd>
</dl>

@author Thomas Kreitler

Definition at line 235 of file FGRotor.h.

#include <FGRotor.h>

Inheritance diagram for FGRotor:

Collaboration diagram for FGRotor:

Public Member Functions
	FGRotor (FGFDMExec exec, Element rotor_element, int num)
	Constructor for FGRotor.

	~FGRotor ()
	Destructor for FGRotor.

double	Calculate (double EnginePower)
	Returns the scalar thrust of the rotor, and adjusts the RPM value.

double	GetA0 (void) const
	Retrieves the rotor's coning angle.

double	GetA1 (void) const
	Retrieves the longitudinal flapping angle with respect to the rotor shaft.

double	GetB1 (void) const
	Retrieves the lateral flapping angle with respect to the rotor shaft.

double	GetCollectiveCtrl (void) const
	Retrieves the collective control input in radians.

double	GetCT (void) const
	Retrieves the thrust coefficient.

double	GetEngineRPM (void) const
	Retrieves the RPMs of the Engine, as seen from this rotor.

double	GetGearRatio (void)
	Tells the rotor's gear ratio, usually the engine asks for this.

double	GetGroundEffectScaleNorm (void) const
	Retrieves the ground effect scaling factor.

double	GetLambda (void) const
	Retrieves the inflow ratio.

double	GetLateralCtrl (void) const
	Retrieves the lateral control input in radians.

double	GetLongitudinalCtrl (void) const
	Retrieves the longitudinal control input in radians.

double	GetMu (void) const
	Retrieves the tip-speed (aka advance) ratio.

double	GetNu (void) const
	Retrieves the induced inflow ratio.

double	GetPhiDW (void) const
	Downwash angle - positive values point leftward (given a horizontal spinning rotor)

double	GetPowerRequired (void) const
	Returns the power required by the rotor.

double	GetRPM (void) const
	Retrieves the RPMs of the rotor.

double	GetThetaDW (void) const
	Downwash angle - positive values point forward (given a horizontal spinning rotor)

double	GetThrust (void) const
	Retrieves the thrust of the rotor.

std::string	GetThrusterLabels (int id, const std::string &delimeter)

std::string	GetThrusterValues (int id, const std::string &delimeter)

double	GetTorque (void) const
	Retrieves the torque.

double	GetVi (void) const
	Retrieves the induced velocity.

void	SetCollectiveCtrl (double c)
	Sets the collective control input in radians.

void	SetEngineRPM (double rpm)

void	SetGroundEffectScaleNorm (double g)
	Sets the ground effect scaling factor.

void	SetLateralCtrl (double c)
	Sets the lateral control input in radians.

void	SetLongitudinalCtrl (double c)
	Sets the longitudinal control input in radians.

void	SetRPM (double rpm)

Public Member Functions inherited from FGThruster
	FGThruster (FGFDMExec FDMExec, Element el, int num)
	Constructor.

virtual	~FGThruster ()
	Destructor.

double	GetGearRatio (void)

std::string	GetName (void)

virtual double	GetPowerRequired (void)

double	GetReverserAngle (void) const

double	GetThrust (void) const

eType	GetType (void)

virtual void	ResetToIC (void)

void	SetName (std::string name)

void	SetReverserAngle (double angle)

Public Member Functions inherited from FGForce
	FGForce (FGFDMExec *FDMExec)
	Constructor.

virtual	~FGForce ()
	Destructor.

const FGColumnVector3 &	GetActingLocation (void) const

double	GetActingLocationX (void) const

double	GetActingLocationY (void) const

double	GetActingLocationZ (void) const

double	GetAnglesToBody (int axis) const

const FGColumnVector3 &	GetAnglesToBody (void) const

virtual const FGColumnVector3 &	GetBodyForces (void)

double	GetBodyXForce (void) const

double	GetBodyYForce (void) const

double	GetBodyZForce (void) const

const FGColumnVector3 &	GetLocation (void) const

double	GetLocationX (void) const

double	GetLocationY (void) const

double	GetLocationZ (void) const

const FGColumnVector3 &	GetMoments (void) const

double	GetPitch (void) const

TransformType	GetTransformType (void) const

double	GetYaw (void) const

void	SetActingLocation (const FGColumnVector3 &vv)

void	SetActingLocation (double x, double y, double z)
	Acting point of application.

void	SetActingLocationX (double x)

void	SetActingLocationY (double y)

void	SetActingLocationZ (double z)

void	SetAnglesToBody (const FGColumnVector3 &vv)

void	SetAnglesToBody (double broll, double bpitch, double byaw)

void	SetLocation (const FGColumnVector3 &vv)

void	SetLocation (double x, double y, double z)

void	SetLocationX (double x)

void	SetLocationY (double y)

void	SetLocationZ (double z)

void	SetPitch (double pitch)

void	SetTransformType (TransformType ii)

void	SetYaw (double yaw)

const FGMatrix33 &	Transform (void) const

void	UpdateCustomTransformMatrix (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.

Additional Inherited Members
Public Types inherited from FGThruster
enum	eType { ttNozzle , ttRotor , ttPropeller , ttDirect }

Public Types inherited from FGForce
enum	TransformType { tNone , tWindBody , tLocalBody , tInertialBody , tCustom }

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)

Public Attributes inherited from FGThruster
struct JSBSim::FGThruster::Inputs	in

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

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

Protected Attributes inherited from FGThruster
int	EngineNum

double	GearRatio

std::string	Name

double	PowerRequired

double	ReverserAngle

double	Thrust

double	ThrustCoeff

eType	Type

Protected Attributes inherited from FGForce
FGFDMExec *	fdmex

std::shared_ptr< FGMassBalance >	MassBalance

FGMatrix33	mT

TransformType	ttype

FGColumnVector3	vActingXYZn

FGColumnVector3	vFn

FGColumnVector3	vMn

FGColumnVector3	vOrient

FGColumnVector3	vXYZn

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

◆ FGRotor()

FGRotor	(	FGFDMExec *	exec,
		Element *	rotor_element,
		int	num
	)

Constructor for FGRotor.

Parameters

exec	a pointer to the main executive object
rotor_element	a pointer to the thruster config file XML element
num	the number of this rotor

Definition at line 75 of file FGRotor.cpp.

  : FGThruster(exec, rotor_element, num),
    rho(0.002356),                                  // environment
    Radius(0.0), BladeNum(0),                       // configuration parameters
    Sense(1.0), NominalRPM(0.0), MinimalRPM(0.0), MaximalRPM(0.0),
    ExternalRPM(0), RPMdefinition(0), ExtRPMsource(NULL), SourceGearRatio(1.0),
    BladeChord(0.0), LiftCurveSlope(0.0), BladeTwist(0.0), HingeOffset(0.0),
    BladeFlappingMoment(0.0), BladeMassMoment(0.0), PolarMoment(0.0),
    InflowLag(0.0), TipLossB(0.0),
    GroundEffectExp(0.0), GroundEffectShift(0.0), GroundEffectScaleNorm(1.0),
    LockNumberByRho(0.0), Solidity(0.0),            // derived parameters
    RPM(0.0), Omega(0.0),                           // dynamic values
    beta_orient(0.0),
    a0(0.0), a_1(0.0), b_1(0.0), a_dw(0.0),
    a1s(0.0), b1s(0.0),
    H_drag(0.0), J_side(0.0), Torque(0.0), C_T(0.0),
    lambda(-0.001), mu(0.0), nu(0.001), v_induced(0.0),
    theta_downwash(0.0), phi_downwash(0.0),
    ControlMap(eMainCtrl),                          // control
    CollectiveCtrl(0.0), LateralCtrl(0.0), LongitudinalCtrl(0.0),
    Transmission(NULL),                             // interaction with engine
    EngineRPM(0.0), MaxBrakePower(0.0), GearLoss(0.0), GearMoment(0.0)
{
  FGColumnVector3 location(0.0, 0.0, 0.0), orientation(0.0, 0.0, 0.0);
  Element *thruster_element;
  double engine_power_est = 0.0;
 
  // initialise/set remaining variables
  SetTransformType(FGForce::tCustom);
  Type = ttRotor;
  GearRatio = 1.0;
 
  dt = exec->GetDeltaT();
  for (int i=0; i<5; i++) R[i] = 0.0;
  for (int i=0; i<5; i++) B[i] = 0.0;
 
  // get positions
  thruster_element = rotor_element->GetParent()->FindElement("sense");
  if (thruster_element) {
    double s = thruster_element->GetDataAsNumber();
    if (s < -0.1) {
      Sense = -1.0; // 'CW' as seen from above
    } else if (s < 0.1) {
      Sense = 0.0;  // 'coaxial'
    } else {
      Sense = 1.0; // 'CCW' as seen from above
    }
  }
 
  thruster_element = rotor_element->GetParent()->FindElement("location");
  if (thruster_element) {
    location = thruster_element->FindElementTripletConvertTo("IN");
  } else {
    cerr << "No thruster location found." << endl;
  }
 
  thruster_element = rotor_element->GetParent()->FindElement("orient");
  if (thruster_element) {
    orientation = thruster_element->FindElementTripletConvertTo("RAD");
  } else {
    cerr << "No thruster orientation found." << endl;
  }
 
  SetLocation(location);
  SetAnglesToBody(orientation);
  InvTransform = Transform().Transposed(); // body to custom/native
 
  // wire controls
  ControlMap = eMainCtrl;
  if (rotor_element->FindElement("controlmap")) {
    string cm = rotor_element->FindElementValue("controlmap");
    cm = to_upper(cm);
    if (cm == "TAIL") {
      ControlMap = eTailCtrl;
    } else if (cm == "TANDEM") {
      ControlMap = eTandemCtrl;
    } else {
      cerr << "# found unknown controlmap: '" << cm << "' using main rotor config."  << endl;
    }
  }
 
  // ExternalRPM -- is the RPM dictated ?
  if (rotor_element->FindElement("ExternalRPM")) {
    ExternalRPM = 1;
    SourceGearRatio = 1.0;
    RPMdefinition = (int) rotor_element->FindElementValueAsNumber("ExternalRPM");
    int rdef = RPMdefinition;
    if (RPMdefinition>=0) {
      // avoid ourself and (still) unknown engines.
      if (!exec->GetPropulsion()->GetEngine(RPMdefinition) || RPMdefinition==num) {
        RPMdefinition = -1;
      } else {
        FGThruster *tr = exec->GetPropulsion()->GetEngine(RPMdefinition)->GetThruster();
        SourceGearRatio = tr->GetGearRatio();
        // cout << "# got sources' GearRatio: " << SourceGearRatio << endl;
      }
    }
    if (RPMdefinition != rdef) {
      cerr << "# discarded given RPM source (" << rdef << ") and switched to external control (-1)." << endl;
    }
  }
 
  // process rotor parameters
  engine_power_est = Configure(rotor_element);
 
  // setup transmission if needed
  if (!ExternalRPM) {
 
    Transmission = new FGTransmission(exec, num, dt);
 
    Transmission->SetThrusterMoment(PolarMoment);
 
    // The MOI sensed behind the gear ( MOI_engine*sqr(GearRatio) ).
    GearMoment = ConfigValueConv(rotor_element, "gearmoment", 0.1*PolarMoment, "SLUG*FT2");
    GearMoment = Constrain(1e-6, GearMoment, 1e9);
    Transmission->SetEngineMoment(GearMoment);
 
    Transmission->SetMaxBrakePower(MaxBrakePower);
 
    GearLoss = ConfigValueConv(rotor_element, "gearloss", 0.0025 * engine_power_est, "HP");
    GearLoss = Constrain(0.0, GearLoss, 1e9);
    GearLoss *= hptoftlbssec;
    Transmission->SetEngineFriction(GearLoss);
 
  }
 
  // shaft representation - a rather simple transform,
  // but using a matrix is safer.
  TboToHsr = { 0.0, 0.0, 1.0,
               0.0, 1.0, 0.0,
               -1.0, 0.0, 0.0 };
  HsrToTbo  =  TboToHsr.Transposed();
 
  // smooth out jumps in hagl reported, otherwise the ground effect
  // calculation would cause jumps too. 1Hz seems sufficient.
  damp_hagl = Filter(1.0, dt);
 
  // enable import-export
  bindmodel(exec->GetPropertyManager().get());
 
  Debug(0);
 
}  // Constructor

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◆ ~FGRotor()

~FGRotor ( )

Destructor for FGRotor.

Definition at line 221 of file FGRotor.cpp.

                 {
  if (Transmission) delete Transmission;
  Debug(1);
}

Member Function Documentation

◆ Calculate()

double Calculate ( double EnginePower )

virtual

Returns the scalar thrust of the rotor, and adjusts the RPM value.

Reimplemented from FGThruster.

Definition at line 671 of file FGRotor.cpp.

{
 
  CalcRotorState();
 
  if (! ExternalRPM) {
    // the RPM values are handled inside Transmission
    Transmission->Calculate(EnginePower, Torque, in.TotalDeltaT);
 
    EngineRPM = Transmission->GetEngineRPM() * GearRatio;
    RPM = Transmission->GetThrusterRPM();
  } else {
    EngineRPM = RPM * GearRatio;
  }
 
  RPM = Constrain(MinimalRPM, RPM, MaximalRPM); // trim again
 
  return Thrust;
}

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◆ GetA0()

double GetA0 ( void ) const

inline

Retrieves the rotor's coning angle.

Definition at line 270 of file FGRotor.h.

270{ return a0; }

◆ GetA1()

double GetA1 ( void ) const

inline

Retrieves the longitudinal flapping angle with respect to the rotor shaft.

Definition at line 272 of file FGRotor.h.

272{ return a1s; }

◆ GetB1()

double GetB1 ( void ) const

inline

Retrieves the lateral flapping angle with respect to the rotor shaft.

Definition at line 274 of file FGRotor.h.

274{ return b1s; }

◆ GetCollectiveCtrl()

double GetCollectiveCtrl ( void ) const

inline

Retrieves the collective control input in radians.

Definition at line 300 of file FGRotor.h.

300{ return CollectiveCtrl; }

◆ GetCT()

double GetCT ( void ) const

inline

Retrieves the thrust coefficient.

Definition at line 285 of file FGRotor.h.

285{ return C_T; }

◆ GetEngineRPM()

double GetEngineRPM ( void ) const

inlinevirtual

Retrieves the RPMs of the Engine, as seen from this rotor.

Reimplemented from FGThruster.

Definition at line 262 of file FGRotor.h.

262{return EngineRPM;} //{ return GearRatio*RPM; }

◆ GetGearRatio()

double GetGearRatio ( void )

inline

Tells the rotor's gear ratio, usually the engine asks for this.

Definition at line 265 of file FGRotor.h.

265{ return GearRatio; }

◆ GetGroundEffectScaleNorm()

double GetGroundEffectScaleNorm ( void ) const

inline

Retrieves the ground effect scaling factor.

Definition at line 295 of file FGRotor.h.

295{ return GroundEffectScaleNorm; }

◆ GetLambda()

double GetLambda ( void ) const

inline

Retrieves the inflow ratio.

Definition at line 277 of file FGRotor.h.

277{ return lambda; }

◆ GetLateralCtrl()

double GetLateralCtrl ( void ) const

inline

Retrieves the lateral control input in radians.

Definition at line 302 of file FGRotor.h.

302{ return LateralCtrl; }

◆ GetLongitudinalCtrl()

double GetLongitudinalCtrl ( void ) const

inline

Retrieves the longitudinal control input in radians.

Definition at line 304 of file FGRotor.h.

304{ return LongitudinalCtrl; }

◆ GetMu()

double GetMu ( void ) const

inline

Retrieves the tip-speed (aka advance) ratio.

Definition at line 279 of file FGRotor.h.

279{ return mu; }

◆ GetNu()

double GetNu ( void ) const

inline

Retrieves the induced inflow ratio.

Definition at line 281 of file FGRotor.h.

281{ return nu; }

◆ GetPhiDW()

double GetPhiDW ( void ) const

inline

Downwash angle - positive values point leftward (given a horizontal spinning rotor)

Definition at line 292 of file FGRotor.h.

292{ return phi_downwash; }

◆ GetPowerRequired()

double GetPowerRequired ( void ) const

inline

Returns the power required by the rotor.

Definition at line 251 of file FGRotor.h.

251{ return PowerRequired; }

◆ GetRPM()

double GetRPM ( void ) const

inlinevirtual

Retrieves the RPMs of the rotor.

Reimplemented from FGThruster.

Definition at line 258 of file FGRotor.h.

258{ return RPM; }

◆ GetThetaDW()

double GetThetaDW ( void ) const

inline

Downwash angle - positive values point forward (given a horizontal spinning rotor)

Definition at line 290 of file FGRotor.h.

290{ return theta_downwash; }

◆ GetThrust()

double GetThrust ( void ) const

inline

Retrieves the thrust of the rotor.

Definition at line 267 of file FGRotor.h.

267{ return Thrust; }

◆ GetThrusterLabels()

string GetThrusterLabels	(	int	id,
		const std::string &	delimeter
	)

virtual

Reimplemented from FGThruster.

Definition at line 789 of file FGRotor.cpp.

{
 
  ostringstream buf;
 
  buf << Name << " RPM (engine " << id << ")";
 
  return buf.str();
 
}

◆ GetThrusterValues()

string GetThrusterValues	(	int	id,
		const std::string &	delimeter
	)

virtual

Reimplemented from FGThruster.

Definition at line 802 of file FGRotor.cpp.

{
 
  ostringstream buf;
 
  buf << RPM;
 
  return buf.str();
 
}

◆ GetTorque()

double GetTorque ( void ) const

inline

Retrieves the torque.

Definition at line 287 of file FGRotor.h.

287{ return Torque; }

◆ GetVi()

double GetVi ( void ) const

inline

Retrieves the induced velocity.

Definition at line 283 of file FGRotor.h.

283{ return v_induced; }

◆ SetCollectiveCtrl()

void SetCollectiveCtrl ( double c )

inline

Sets the collective control input in radians.

Definition at line 307 of file FGRotor.h.

307{ CollectiveCtrl = c; }

◆ SetEngineRPM()

void SetEngineRPM ( double rpm )

inlinevirtual

Reimplemented from FGThruster.

Definition at line 263 of file FGRotor.h.

263{EngineRPM = rpm;} //{ RPM = rpm/GearRatio; }

◆ SetGroundEffectScaleNorm()

void SetGroundEffectScaleNorm ( double g )

inline

Sets the ground effect scaling factor.

Definition at line 297 of file FGRotor.h.

297{ GroundEffectScaleNorm = g; }

◆ SetLateralCtrl()

void SetLateralCtrl ( double c )

inline

Sets the lateral control input in radians.

Definition at line 309 of file FGRotor.h.

309{ LateralCtrl = c; }

◆ SetLongitudinalCtrl()

void SetLongitudinalCtrl ( double c )

inline

Sets the longitudinal control input in radians.

Definition at line 311 of file FGRotor.h.

311{ LongitudinalCtrl = c; }

◆ SetRPM()

void SetRPM ( double rpm )

inlinevirtual

Reimplemented from FGThruster.

Definition at line 259 of file FGRotor.h.

259{ RPM = rpm; }

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

Detailed Description

Configuration File Format

Configuration Parameters:

Notes:

- Controls -

- Tail/tandem rotor -

- Sense -

- Engine issues -

- Scaling the ground effect -

- Development hints -

References:

Public Member Functions

Additional Inherited Members

Constructor & Destructor Documentation

◆ FGRotor()

◆ ~FGRotor()

Member Function Documentation

◆ Calculate()

◆ GetA0()

◆ GetA1()

◆ GetB1()

◆ GetCollectiveCtrl()

◆ GetCT()

◆ GetEngineRPM()

◆ GetGearRatio()

◆ GetGroundEffectScaleNorm()

◆ GetLambda()

◆ GetLateralCtrl()

◆ GetLongitudinalCtrl()

◆ GetMu()

◆ GetNu()

◆ GetPhiDW()

◆ GetPowerRequired()

◆ GetRPM()

◆ GetThetaDW()

◆ GetThrust()

◆ GetThrusterLabels()

◆ GetThrusterValues()

◆ GetTorque()

◆ GetVi()

◆ SetCollectiveCtrl()

◆ SetEngineRPM()

◆ SetGroundEffectScaleNorm()

◆ SetLateralCtrl()

◆ SetLongitudinalCtrl()

◆ SetRPM()