1 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
7 ------------- Copyright (C) 2000 Jon S. Berndt (jon@jsbsim.org) -------------
9 This program is free software; you can redistribute it and/or modify it under
10 the terms of the GNU Lesser General Public License as published by the Free Software
11 Foundation; either version 2 of the License, or (at your option) any later
14 This program is distributed in the hope that it will be useful, but WITHOUT
15 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
16 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
19 You should have received a copy of the GNU Lesser General Public License along with
20 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
21 Place - Suite 330, Boston, MA 02111-1307, USA.
23 Further information about the GNU Lesser General Public License can also be found on
24 the world wide web at http://www.gnu.org.
27 --------------------------------------------------------------------------------
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37 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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41 #include "FGThruster.h"
42 #include "math/FGTable.h"
44 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
46 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
48 #define ID_PROPELLER "$Id: FGPropeller.h,v 1.19 2011/09/24 14:26:46 jentron Exp $"
50 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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60 /** FGPropeller models a propeller given the tabular data for Ct and Cp,
61 indexed by the advance ratio "J".
63 <h3>Configuration File Format:</h3>
65 <sense> {1 | -1} </sense>
66 <propeller name="{string}">
68 <diameter unit="IN"> {number} </diameter>
69 <numblades> {number} </numblades>
70 <gearratio> {number} </gearratio>
71 <minpitch> {number} </minpitch>
72 <maxpitch> {number} </maxpitch>
73 <minrpm> {number} </minrpm>
74 <maxrpm> {number} </maxrpm>
75 <constspeed> {number} </constspeed>
76 <reversepitch> {number} </reversepitch>
77 <p_factor> {number} </p_factor>
78 <ct_factor> {number} </ct_factor>
79 <cp_factor> {number} </cp_factor>
81 <table name="C_THRUST" type="internal">
87 <table name="C_POWER" type="internal">
93 <table name="CT_MACH" type="internal">
99 <table name="CP_MACH" type="internal">
109 <h3>Configuration Parameters:</h3>
111 \<ixx> - Propeller rotational inertia.
112 \<diameter> - Propeller disk diameter.
113 \<numblades> - Number of blades.
114 \<gearratio> - Ratio of (engine rpm) / (prop rpm).
115 \<minpitch> - Minimum blade pitch angle.
116 \<maxpitch> - Maximum blade pitch angle.
117 \<minrpm> - Minimum rpm target for constant speed propeller.
118 \<maxrpm> - Maximum rpm target for constant speed propeller.
119 \<constspeed> - 1 = constant speed mode, 0 = manual pitch mode.
120 \<reversepitch> - Blade pitch angle for reverse.
121 \<sense> - Direction of rotation (1=clockwise as viewed from cockpit,
122 -1=anti-clockwise as viewed from cockpit). Sense is
123 specified in the parent tag of the propeller.
124 \<p_factor> - P factor.
125 \<ct_factor> - A multiplier for the coefficients of thrust.
126 \<cp_factor> - A multiplier for the coefficients of power.
129 Two tables are needed. One for coefficient of thrust (Ct) and one for
130 coefficient of power (Cp).
132 Two tables are optional. They apply a factor to Ct and Cp based on the
136 Several references were helpful, here:<ul>
137 <li>Barnes W. McCormick, "Aerodynamics, Aeronautics, and Flight Mechanics",
138 Wiley & Sons, 1979 ISBN 0-471-03032-5</li>
139 <li>Edwin Hartman, David Biermann, "The Aerodynamic Characteristics of
140 Full Scale Propellers Having 2, 3, and 4 Blades of Clark Y and R.A.F. 6
141 Airfoil Sections", NACA Report TN-640, 1938 (?)</li>
142 <li>Various NACA Technical Notes and Reports</li>
144 @author Jon S. Berndt
145 @version $Id: FGPropeller.h,v 1.19 2011/09/24 14:26:46 jentron Exp $
150 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
152 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
154 class FGPropeller : public FGThruster {
157 /** Constructor for FGPropeller.
158 @param exec a pointer to the main executive object
159 @param el a pointer to the thruster config file XML element
160 @param num the number of this propeller */
161 FGPropeller(FGFDMExec* exec, Element* el, int num = 0);
163 /// Destructor for FGPropeller - deletes the FGTable objects
166 /** Sets the Revolutions Per Minute for the propeller. Normally the propeller
167 instance will calculate its own rotational velocity, given the Torque
168 produced by the engine and integrating over time using the standard
169 equation for rotational acceleration "a": a = Q/I , where Q is Torque and
170 I is moment of inertia for the propeller.
171 @param rpm the rotational velocity of the propeller */
172 void SetRPM(double rpm) {RPM = rpm;}
174 /** Sets the Revolutions Per Minute for the propeller using the engine gear ratio **/
175 void SetEngineRPM(double rpm) {RPM = rpm/GearRatio;}
177 /// Returns true of this propeller is variable pitch
178 bool IsVPitch(void) {return MaxPitch != MinPitch;}
180 /** This commands the pitch of the blade to change to the value supplied.
181 This call is meant to be issued either from the cockpit or by the flight
182 control system (perhaps to maintain constant RPM for a constant-speed
183 propeller). This value will be limited to be within whatever is specified
184 in the config file for Max and Min pitch. It is also one of the lookup
185 indices to the power and thrust tables for variable-pitch propellers.
186 @param pitch the pitch of the blade in degrees. */
187 void SetPitch(double pitch) {Pitch = pitch;}
189 void SetAdvance(double advance) {Advance = advance;}
191 /// Sets the P-Factor constant
192 void SetPFactor(double pf) {P_Factor = pf;}
194 /// Sets propeller into constant speed mode, or manual pitch mode
195 void SetConstantSpeed(int mode) {ConstantSpeed = mode;}
197 /// Sets coefficient of thrust multiplier
198 void SetCtFactor(double ctf) {CtFactor = ctf;}
200 /// Sets coefficient of power multiplier
201 void SetCpFactor(double cpf) {CpFactor = cpf;}
203 /** Sets the rotation sense of the propeller.
204 @param s this value should be +/- 1 ONLY. +1 indicates clockwise rotation as
205 viewed by someone standing behind the engine looking forward into
206 the direction of flight. */
207 void SetSense(double s) { Sense = s;}
209 /// Retrieves the pitch of the propeller in degrees.
210 double GetPitch(void) { return Pitch; }
212 /// Retrieves the RPMs of the propeller
213 double GetRPM(void) const { return RPM; }
215 /// Calculates the RPMs of the engine based on gear ratio
216 double GetEngineRPM(void) const { return RPM * GearRatio; }
218 /// Retrieves the propeller moment of inertia
219 double GetIxx(void) { return Ixx; }
221 /// Retrieves the coefficient of thrust multiplier
222 double GetCtFactor(void) { return CtFactor; }
224 /// Retrieves the coefficient of power multiplier
225 double GetCpFactor(void) { return CpFactor; }
227 /// Retrieves the propeller diameter
228 double GetDiameter(void) { return Diameter; }
230 /// Retrieves propeller thrust table
231 FGTable* GetCThrustTable(void) const { return cThrust;}
232 /// Retrieves propeller power table
233 FGTable* GetCPowerTable(void) const { return cPower; }
235 /// Retrieves propeller thrust Mach effects factor
236 FGTable* GetCtMachTable(void) const { return CtMach; }
237 /// Retrieves propeller power Mach effects factor
238 FGTable* GetCpMachTable(void) const { return CpMach; }
240 /// Retrieves the Torque in foot-pounds (Don't you love the English system?)
241 double GetTorque(void) { return vTorque(eX); }
243 /** Retrieves the power required (or "absorbed") by the propeller -
244 i.e. the power required to keep spinning the propeller at the current
245 velocity, air density, and rotational rate. */
246 double GetPowerRequired(void);
248 /** Calculates and returns the thrust produced by this propeller.
249 Given the excess power available from the engine (in foot-pounds), the thrust is
250 calculated, as well as the current RPM. The RPM is calculated by integrating
251 the torque provided by the engine over what the propeller "absorbs"
252 (essentially the "drag" of the propeller).
253 @param PowerAvailable this is the excess power provided by the engine to
254 accelerate the prop. It could be negative, dictating that the propeller
256 @return the thrust in pounds */
257 double Calculate(double EnginePower);
258 FGColumnVector3 GetPFactor(void);
259 string GetThrusterLabels(int id, string delimeter);
260 string GetThrusterValues(int id, string delimeter);
262 void SetReverseCoef (double c) { Reverse_coef = c; }
263 double GetReverseCoef (void) { return Reverse_coef; }
264 void SetReverse (bool r) { Reversed = r; }
265 bool GetReverse (void) { return Reversed; }
266 void SetFeather (bool f) { Feathered = f; }
267 bool GetFeather (void) { return Feathered; }
268 double GetThrustCoefficient(void) const {return ThrustCoeff;}
269 double GetHelicalTipMach(void) const {return HelicalTipMach;}
270 int GetConstantSpeed(void) const {return ConstantSpeed;}
271 void SetInducedVelocity(double Vi) {Vinduced = Vi;}
272 double GetInducedVelocity(void) const {return Vinduced;}
291 double HelicalTipMach;
293 FGColumnVector3 vTorque;
301 void Debug(int from);
302 double ReversePitch; // Pitch, when fully reversed
303 bool Reversed; // true, when propeller is reversed
304 double Reverse_coef; // 0 - 1 defines AdvancePitch (0=MIN_PITCH 1=REVERSE_PITCH)
305 bool Feathered; // true, if feather command
308 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%