01/01/10 T.Kreitler test implementation
01/10/11 T.Kreitler changed to single rotor model
03/06/11 T.Kreitler added brake, clutch, and experimental free-wheeling-unit
+02/05/12 T.Kreitler brake, clutch, and FWU now in FGTransmission class
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
SENTRY
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
#include "FGThruster.h"
+#include "FGTransmission.h"
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
DEFINITIONS
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-#define ID_ROTOR "$Id: FGRotor.h,v 1.12 2011/10/15 21:30:28 jentron Exp $"
+#define ID_ROTOR "$Id: FGRotor.h,v 1.14 2012/03/18 15:48:36 jentron Exp $"
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FORWARD DECLARATIONS
<groundeffectexp> {number} </groundeffectexp>
<groundeffectshift unit="{LENGTH}"> {number} </groundeffectshift>
- <freewheelthresh> {number} </freewheelthresh>
</rotor>
// LENGTH means any of the supported units, same for ANGLE and MOMENT.
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
+ 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.
+ \<groundeffectshift> - Further adjustment of ground effect, approx. hub height or slightly above
+ (This lessens the influence of the ground effect).
</pre>
-<h3>Notes:</h3>
+<h3>Notes:</h3>
<h4>- Controls -</h4>
The behavior of the rotor is controlled/influenced by following inputs.<ul>
<li> The power provided by the engine. This is handled by the regular engine controls.</li>
- <li> The collective control input. This is read from the <tt>fdm</tt> property
+ <li> The collective control input. This is read from the <tt>fdm</tt> property
<tt>propulsion/engine[x]/collective-ctrl-rad</tt>. See below for tail rotor</li>
<li> The lateral cyclic input. Read from
<tt>propulsion/engine[x]/lateral-ctrl-rad</tt>.</li>
<li> The longitudinal cyclic input. Read from
<tt>propulsion/engine[x]/longitudinal-ctrl-rad</tt>.</li>
- <li> The tail collective (aka antitorque, aka pedal) control input. Read from
- <tt>propulsion/engine[x]/antitorque-ctrl-rad</tt> or
+ <li> The tail rotor collective (aka antitorque, aka pedal) control input. Read from
+ <tt>propulsion/engine[x]/antitorque-ctrl-rad</tt> or
<tt>propulsion/engine[x]/tail-collective-ctrl-rad</tt>.</li>
</ul>
is linked to to the main (=first, =0) rotor, and specifing
<tt>\<controlmap\> TAIL \</controlmap\></tt> tells this rotor to read the
collective input from <tt>propulsion/engine[1]/antitorque-ctrl-rad</tt>
- (The TAIL-map ignores lateral and longitudinal input). The rotor needs to be
+ (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.
</ul>
+ <h4>- Scaling the ground effect -</h4>
+
+ The property <tt>propulsion/engine[x]/groundeffect-scale-norm</tt> 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.
+
<h4>- Development hints -</h4>
Setting <tt>\<ExternalRPM> -1 \</ExternalRPM></tt> the rotor's RPM is controlled by
when developing a FDM.
-<h3>References:</h3>
+<h3>References:</h3>
<dl>
<dt>/SH79/</dt><dd>Shaugnessy, J. D., Deaux, Thomas N., and Yenni, Kenneth R.,
- "Development and Validation of a Piloted Simulation of a
+ "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>
+ 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>
+ Aspects of Helicopter Stability", NACA TN-1982, 1949.</dd>
</dl>
@author Thomas Kreitler
- @version $Id: FGRotor.h,v 1.12 2011/10/15 21:30:28 jentron Exp $
+ @version $Id: FGRotor.h,v 1.14 2012/03/18 15:48:36 jentron Exp $
*/
CLASS DECLARATION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-class FGTransmission : public FGJSBBase {
-
-public:
- FGTransmission(FGFDMExec *exec, int num);
- ~FGTransmission();
-
- void Calculate(double EnginePower, double ThrusterTorque, double dt);
-
- void SetMaxBrakePower(double x) {MaxBrakePower=x;}
- double GetMaxBrakePower() const {return MaxBrakePower;}
- void SetEngineFriction(double x) {EngineFriction=x;}
- double GetEngineFriction() const {return EngineFriction;}
- void SetEngineMoment(double x) {EngineMoment=x;}
- double GetEngineMoment() const {return EngineMoment;}
- void SetThrusterMoment(double x) {ThrusterMoment=x;}
- double GetThrusterMoment() const {return ThrusterMoment;}
-
- double GetFreeWheelTransmission() const {return FreeWheelTransmission;}
- double GetEngineRPM() {return EngineRPM;}
- double GetThrusterRPM() {return ThrusterRPM;}
-
- double GetBrakeCtrl() const {return BrakeCtrlNorm;}
- void SetBrakeCtrl(double x) {BrakeCtrlNorm=x;}
- void SetClutchCtrlNorm(double x) {ClutchCtrlNorm=x;}
-
-private:
- bool BindModel(int num);
- // void Debug(int from);
-
- inline double omega_to_rpm(double w) {return w * 9.54929658551372014613302580235;} // omega/(2.0*PI) * 60.0
- inline double rpm_to_omega(double r) {return r * .104719755119659774615421446109;} // (rpm/60.0)*2.0*PI
-
- Filter FreeWheelLag;
- double FreeWheelTransmission; // state, 0: free, 1:locked
-
- double ThrusterMoment;
- double EngineMoment; // estimated MOI of gear and engine, influences acceleration
- double EngineFriction; // estimated friction in gear and possibly engine
-
- double ClutchCtrlNorm; // also in FGThruster.h
- double BrakeCtrlNorm;
- double MaxBrakePower;
-
- double EngineRPM;
- double ThrusterRPM;
- FGPropertyManager* PropertyManager;
-
-};
-
-//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
class FGRotor : public FGThruster {
enum eCtrlMapping {eMainCtrl=0, eTailCtrl, eTandemCtrl};
/// Destructor for FGRotor
~FGRotor();
- /** Returns the power required by the rotor. */
+ /// Returns the power required by the rotor.
double GetPowerRequired(void)const { return PowerRequired; }
- /** Returns the scalar thrust of the rotor, and adjusts the RPM value. */
+ /// Returns the scalar thrust of the rotor, and adjusts the RPM value.
double Calculate(double EnginePower);
/// Retrieves the torque
double GetTorque(void) const { return Torque; }
- /// Downwash angle - currently only valid for a rotor that spins horizontally
+ /// Downwash angle - positive values point forward (given a horizontal spinning rotor)
double GetThetaDW(void) const { return theta_downwash; }
- /// Downwash angle - currently only valid for a rotor that spins horizontally
+ /// Downwash angle - positive values point leftward (given a horizontal spinning rotor)
double GetPhiDW(void) const { return phi_downwash; }
+ /// Retrieves the ground effect scaling factor.
+ double GetGroundEffectScaleNorm(void) const { return GroundEffectScaleNorm; }
+ /// Sets the ground effect scaling factor.
+ void SetGroundEffectScaleNorm(double g) { GroundEffectScaleNorm = g; }
+
/// Retrieves the collective control input in radians.
double GetCollectiveCtrl(void) const { return CollectiveCtrl; }
/// Retrieves the lateral control input in radians.
void SetLongitudinalCtrl(double c) { LongitudinalCtrl = c; }
// Stubs. Only main rotor RPM is returned
- string GetThrusterLabels(int id, string delimeter);
- string GetThrusterValues(int id, string delimeter);
+ string GetThrusterLabels(int id, const string& delimeter);
+ string GetThrusterValues(int id, const string& delimeter);
private:
double ConfigValue( Element* e, const string& ename, double default_val=0.0,
bool tell=false);
- void Configure(Element* rotor_element);
+ double Configure(Element* rotor_element);
void CalcRotorState(void);
void calc_flapping_angles(double theta_0, const FGColumnVector3 &pqr_fus_w);
void calc_drag_and_side_forces(double theta_0);
void calc_torque(double theta_0);
+ void calc_downwash_angles();
// transformations
FGColumnVector3 hub_vel_body2ca( const FGColumnVector3 &uvw, const FGColumnVector3 &pqr,
FGPropertyManager* ExtRPMsource;
double SourceGearRatio;
+ // 'real' rotor parameters
double BladeChord;
double LiftCurveSlope;
double BladeTwist;
double InflowLag;
double TipLossB;
+ // groundeffect
double GroundEffectExp;
double GroundEffectShift;
+ double GroundEffectScaleNorm;
// derived parameters
double LockNumberByRho;
double lambda; // inflow ratio
double mu; // tip-speed ratio
double nu; // induced inflow ratio
- double v_induced; // induced velocity, always positive [ft/s]
+ double v_induced; // induced velocity, usually positive [ft/s]
double theta_downwash;
double phi_downwash;
projects / flightgear.git / blobdiff