// basically P = Q*w and Q_Engine + (-Q_Rotor) = J * dw/dt, J = Moment
//
void FGTransmission::Calculate(double EnginePower, double ThrusterTorque, double dt) {
double coupling = 1.0, coupling_sq = 1.0;
double fw_mult = 1.0;
double d_omega = 0.0, engine_d_omega = 0.0, thruster_d_omega = 0.0; // relative changes
double engine_omega = rpm_to_omega(EngineRPM);
double safe_engine_omega = engine_omega < 1e-1 ? 1e-1 : engine_omega;
double engine_torque = EnginePower / safe_engine_omega;
double thruster_omega = rpm_to_omega(ThrusterRPM);
double safe_thruster_omega = thruster_omega < 1e-1 ? 1e-1 : thruster_omega;
engine_torque -= EngineFriction / safe_engine_omega;
ThrusterTorque += Constrain(0.0, BrakeCtrlNorm, 1.0) * MaxBrakePower / safe_thruster_omega;
// would the FWU release ?
engine_d_omega = engine_torque/EngineMoment * dt;
thruster_d_omega = - ThrusterTorque/ThrusterMoment * dt;
if ( thruster_omega+thruster_d_omega > engine_omega+engine_d_omega ) {
// don't drive the engine
FreeWheelTransmission = 0.0;
} else {
FreeWheelTransmission = 1.0;
}
fw_mult = FreeWheelLag.execute(FreeWheelTransmission);
coupling = fw_mult * Constrain(0.0, ClutchCtrlNorm, 1.0);
if (coupling < 0.999999) { // are the separate calculations needed ?
// assume linear transfer
engine_d_omega =
(engine_torque - ThrusterTorque*coupling)/(ThrusterMoment*coupling + EngineMoment) * dt;
thruster_d_omega =
(engine_torque*coupling - ThrusterTorque)/(ThrusterMoment + EngineMoment*coupling) * dt;
EngineRPM += omega_to_rpm(engine_d_omega);
ThrusterRPM += omega_to_rpm(thruster_d_omega);
// simulate transit to static friction
coupling_sq = coupling*coupling;
EngineRPM = (1.0-coupling_sq) * EngineRPM + coupling_sq * 0.02 * (49.0*EngineRPM + ThrusterRPM);
ThrusterRPM = (1.0-coupling_sq) * ThrusterRPM + coupling_sq * 0.02 * (EngineRPM + 49.0*ThrusterRPM);
// enforce equal rpm
if ( fabs(EngineRPM-ThrusterRPM) < 1e-3 ) {
EngineRPM = ThrusterRPM = 0.5 * (EngineRPM+ThrusterRPM);
}
} else {
d_omega = (engine_torque - ThrusterTorque)/(ThrusterMoment + EngineMoment) * dt;
EngineRPM = ThrusterRPM += omega_to_rpm(d_omega);
}
// nothing will turn backward
if (EngineRPM < 0.0 ) EngineRPM = 0.0;
if (ThrusterRPM < 0.0 ) ThrusterRPM = 0.0;
}
boolean VertexManip::Manipulating (Event& e) {
Rubberband* r = GetRubberband();
if (r == nil) {
return false;
}
if (e.eventType == MotionEvent) {
Constrain(e);
r->Track(e.x, e.y);
} else if (e.eventType == DownEvent) {
Constrain(e);
if (e.button == LEFTMOUSE) {
GetGrowingVertices()->AddVertex(e.x, e.y);
_origx = e.x;
_origy = e.y;
} else if (e.button == MIDDLEMOUSE) {
GetGrowingVertices()->AddVertex(e.x, e.y);
return false;
} else if (e.button == RIGHTMOUSE) {
GetGrowingVertices()->RemoveVertex();
if (GetGrowingVertices()->Count()==0) return false;
}
}
return true;
}
void pokef_in3(t_pokef *x, long n)
{
if (n)
x->l_chan = Constrain(n,1,4) - 1;
else
x->l_chan = 0;
}
void Slider::Slide (Event& e) {
IntCoord newleft, newbot, dummy;
boolean control = e.control;
Listen(allEvents);
SlidingRect r(output, canvas, left, bottom, right, top, e.x, e.y);
CalcLimits(e);
do {
switch (e.eventType) {
case MotionEvent:
e.target->GetRelative(e.x, e.y, this);
Constrain(e);
r.Track(e.x, e.y);
if ((syncScroll && !control) || (!syncScroll && control)) {
r.Erase();
r.GetCurrent(newleft, newbot, dummy, dummy);
Move(ViewX(newleft - left), ViewY(newbot - bottom));
interactor->Adjust(*shown);
}
break;
default:
break;
}
Read(e);
} while (e.eventType != UpEvent);
r.GetCurrent(newleft, newbot, dummy, dummy);
Move(ViewX(newleft - left), ViewY(newbot - bottom));
Listen(input);
}
void TNSpline::Smooth()
{
for (int i = 0; i < 3; ++i)
{
SNSpline::Smooth();
Constrain();
}
}
//////////////////
// User let go of mouse: leave size-drag mode
//
void CSizerBar::OnLButtonUp(UINT nFlags, CPoint pt)
{
if (m_bDragging) {
pt = Constrain(pt); // don't go outside constraints
pt = Rectify(pt); // clip x or y
CPoint ptDelta = pt-m_ptOriginal; // distance moved
CancelDrag(); // cancel drag mode
NotifyMoved(ptDelta); // notify parent
}
}
void DragManip::Grasp (Event& e) {
_grasp_e = e;
if (!_origPreset) {
_origx = e.x;
_origy = e.y;
}
Constrain(e);
if (_r != nil) _r->Track(e.x, e.y);
}
//////////////////
// User moved mouse: erase old bar and draw in new position. XOR makes this
// easy. Keep track of previous point.
//
void CSizerBar::OnMouseMove(UINT nFlags, CPoint pt)
{
if (m_bDragging) {
DrawBar(); // erase old bar
pt = Constrain(pt); // don't go outside constrained rect!
pt = Rectify(pt); // clip x or y depending if horizontal or vert
CPoint ptDelta = pt-m_ptPrevious;
m_rcBar += ptDelta; // move bar...
DrawBar(); // and draw
m_ptPrevious = pt; // remember for next mousemove
}
}
void DFS(int x, int y, int n, int m, int *step) {
matrix[y][x] = '#';
int nx, ny;
for (int i = 0; i < 4; ++i) {
nx = x + move[i][0];
ny = y + move[i][1];
if (Constrain(nx, ny, n, m) && matrix[ny][nx] == '.') {
matrix[ny][nx] = '#';
++(*step);
DFS(nx, ny, n, m, step);
}
}
}
boolean DragManip::Manipulating (Event& e) {
if (_r == nil) {
return false;
}
if (e.eventType == MotionEvent) {
Constrain(e);
_r->Track(e.x, e.y);
} else if (e.eventType == UpEvent) {
return false;
}
return true;
}
bool wxCompositeShape::Recompute()
{
int noIterations = 0;
bool changed = TRUE;
while (changed && (noIterations < 500))
{
changed = Constrain();
noIterations ++;
}
/*
#ifdef wx_x
if (changed)
cerr << "Warning: constraint algorithm failed after 500 iterations.\n";
#endif
*/
return (!changed);
}
hConstraint Constraint::ConstrainCoincident(hEntity ptA, hEntity ptB) {
return Constrain(Type::POINTS_COINCIDENT, ptA, ptB,
Entity::NO_ENTITY, Entity::NO_ENTITY, /*other=*/false, /*other2=*/false);
}
bool FGTurboProp::Load(FGFDMExec* exec, Element *el)
{
MaxStartingTime = 999999; //very big timeout -> infinite
Ielu_max_torque=-1;
// ToDo: Need to make sure units are properly accounted for below.
if (el->FindElement("milthrust"))
MilThrust = el->FindElementValueAsNumberConvertTo("milthrust","LBS");
if (el->FindElement("idlen1"))
IdleN1 = el->FindElementValueAsNumber("idlen1");
if (el->FindElement("idlen2"))
IdleN2 = el->FindElementValueAsNumber("idlen2");
if (el->FindElement("maxn1"))
MaxN1 = el->FindElementValueAsNumber("maxn1");
if (el->FindElement("maxn2"))
MaxN2 = el->FindElementValueAsNumber("maxn2");
if (el->FindElement("betarangeend"))
BetaRangeThrottleEnd = el->FindElementValueAsNumber("betarangeend")/100.0;
BetaRangeThrottleEnd = Constrain(0.0, BetaRangeThrottleEnd, 0.99999);
if (el->FindElement("reversemaxpower"))
ReverseMaxPower = el->FindElementValueAsNumber("reversemaxpower")/100.0;
if (el->FindElement("maxpower"))
MaxPower = el->FindElementValueAsNumber("maxpower");
if (el->FindElement("idlefuelflow")) {
cerr << el->ReadFrom() << "Note: 'idlefuelflow' is obsolete, "
<< "use the 'CombustionEfficiency_N1' table instead." << endl;
}
if (el->FindElement("psfc"))
PSFC = el->FindElementValueAsNumber("psfc");
if (el->FindElement("n1idle_max_delay"))
Idle_Max_Delay = el->FindElementValueAsNumber("n1idle_max_delay");
if (el->FindElement("maxstartingtime"))
MaxStartingTime = el->FindElementValueAsNumber("maxstartingtime");
if (el->FindElement("startern1"))
StarterN1 = el->FindElementValueAsNumber("startern1");
if (el->FindElement("ielumaxtorque"))
Ielu_max_torque = el->FindElementValueAsNumber("ielumaxtorque");
if (el->FindElement("itt_delay"))
ITT_Delay = el->FindElementValueAsNumber("itt_delay");
Element *table_element;
string name;
FGPropertyManager* PropertyManager = exec->GetPropertyManager();
while (true) {
table_element = el->FindNextElement("table");
if (!table_element) break;
name = table_element->GetAttributeValue("name");
if (name == "EnginePowerVC") {
EnginePowerVC = new FGTable(PropertyManager, table_element);
} else if (name == "EnginePowerRPM_N1") {
EnginePowerRPM_N1 = new FGTable(PropertyManager, table_element);
} else if (name == "ITT_N1") {
ITT_N1 = new FGTable(PropertyManager, table_element);
} else if (name == "CombustionEfficiency_N1") {
CombustionEfficiency_N1 = new FGTable(PropertyManager, table_element);
} else {
cerr << el->ReadFrom() << "Unknown table type: " << name
<< " in turboprop definition." << endl;
}
}
// Pre-calculations and initializations
delay=1;
N1_factor = MaxN1 - IdleN1;
N2_factor = MaxN2 - IdleN2;
OilTemp_degK = in.TAT_c + 273.0;
// default table based on '9.333 - (N1)/12.0' approximation
// gives 430%Fuel at 60%N1
if (! CombustionEfficiency_N1) {
CombustionEfficiency_N1 = new FGTable(6);
*CombustionEfficiency_N1 << 60.0 << 12.0/52.0;
*CombustionEfficiency_N1 << 82.0 << 12.0/30.0;
*CombustionEfficiency_N1 << 96.0 << 12.0/16.0;
*CombustionEfficiency_N1 << 100.0 << 1.0;
*CombustionEfficiency_N1 << 104.0 << 1.5;
*CombustionEfficiency_N1 << 110.0 << 6.0;
}
return true;
}
void FGAccelerations::CalculateFrictionForces(double dt)
{
vector<LagrangeMultiplier*>& multipliers = *in.MultipliersList;
size_t n = multipliers.size();
vFrictionForces.InitMatrix();
vFrictionMoments.InitMatrix();
// If no gears are in contact with the ground then return
if (!n) return;
vector<double> a(n*n); // Will contain Jac*M^-1*Jac^T
vector<double> rhs(n);
// Assemble the linear system of equations
for (unsigned int i=0; i < n; i++) {
FGColumnVector3 U = multipliers[i]->ForceJacobian;
FGColumnVector3 r = multipliers[i]->LeverArm;
FGColumnVector3 v1 = U / in.Mass;
FGColumnVector3 v2 = in.Jinv * (r*U); // Should be J^-T but J is symmetric and so is J^-1
for (unsigned int j=0; j < i; j++)
a[i*n+j] = a[j*n+i]; // Takes advantage of the symmetry of Jac^T*M^-1*Jac
for (unsigned int j=i; j < n; j++) {
U = multipliers[j]->ForceJacobian;
r = multipliers[j]->LeverArm;
a[i*n+j] = DotProduct(U, v1 + v2*r);
}
}
// Assemble the RHS member
// Translation
FGColumnVector3 vdot = vUVWdot;
if (dt > 0.) // Zeroes out the relative movement between the aircraft and the ground
vdot += (in.vUVW - in.Tec2b * in.TerrainVelocity) / dt;
// Rotation
FGColumnVector3 wdot = vPQRdot;
if (dt > 0.) // Zeroes out the relative movement between the aircraft and the ground
wdot += (in.vPQR - in.Tec2b * in.TerrainAngularVel) / dt;
// Prepare the linear system for the Gauss-Seidel algorithm :
// 1. Compute the right hand side member 'rhs'
// 2. Divide every line of 'a' and 'rhs' by a[i,i]. This is in order to save
// a division computation at each iteration of Gauss-Seidel.
for (unsigned int i=0; i < n; i++) {
double d = a[i*n+i];
FGColumnVector3 U = multipliers[i]->ForceJacobian;
FGColumnVector3 r = multipliers[i]->LeverArm;
rhs[i] = -DotProduct(U, vdot + wdot*r)/d;
for (unsigned int j=0; j < n; j++)
a[i*n+j] /= d;
}
// Resolve the Lagrange multipliers with the projected Gauss-Seidel method
for (int iter=0; iter < 50; iter++) {
double norm = 0.;
for (unsigned int i=0; i < n; i++) {
double lambda0 = multipliers[i]->value;
double dlambda = rhs[i];
for (unsigned int j=0; j < n; j++)
dlambda -= a[i*n+j]*multipliers[j]->value;
multipliers[i]->value = Constrain(multipliers[i]->Min, lambda0+dlambda, multipliers[i]->Max);
dlambda = multipliers[i]->value - lambda0;
norm += fabs(dlambda);
}
if (norm < 1E-5) break;
}
// Calculate the total friction forces and moments
for (unsigned int i=0; i< n; i++) {
double lambda = multipliers[i]->value;
FGColumnVector3 U = multipliers[i]->ForceJacobian;
FGColumnVector3 r = multipliers[i]->LeverArm;
FGColumnVector3 F = lambda * U;
vFrictionForces += F;
vFrictionMoments += r * F;
}
FGColumnVector3 accel = vFrictionForces / in.Mass;
FGColumnVector3 omegadot = in.Jinv * vFrictionMoments;
vBodyAccel += accel;
vUVWdot += accel;
vUVWidot += in.Tb2i * accel;
vPQRdot += omegadot;
vPQRidot += omegadot;
}
void Constraint::ConstrainCoincident(hEntity ptA, hEntity ptB) {
Constrain(POINTS_COINCIDENT, ptA, ptB,
Entity::NO_ENTITY, Entity::NO_ENTITY, false, false);
}
void Constraint::Constrain(int type, hEntity ptA, hEntity ptB, hEntity entityA){
Constrain(type, ptA, ptB, entityA, Entity::NO_ENTITY, false, false);
}
hConstraint Constraint::Constrain(Constraint::Type type, hEntity ptA, hEntity ptB, hEntity entityA){
return Constrain(type, ptA, ptB, entityA, Entity::NO_ENTITY, /*other=*/false, /*other2=*/false);
}
// 1. read configuration and try to fill holes, ymmv
// 2. calculate derived parameters and transforms
void FGRotor::rotor::configure(int f, const rotor *xmain)
{
double estimate;
const bool yell = true;
const bool silent = false;
flags = f;
estimate = (xmain) ? 2.0 * xmain->Radius * 0.2 : 42.0;
Radius = 0.5 * cnf_elem("diameter", estimate, "FT", yell);
estimate = (xmain) ? xmain->BladeNum : 2.0;
estimate = Constrain(1.0,estimate,4.0);
BladeNum = (int) cnf_elem("numblades", estimate, yell);
estimate = (xmain) ? - xmain->Radius * 1.05 - Radius : - 0.025 * Radius ;
RelDistance_xhub = cnf_elem("xhub", estimate, "FT", yell);
RelShift_yhub = cnf_elem("yhub", 0.0, "FT", silent);
estimate = - 0.1 * Radius - 4.0;
RelHeight_zhub = cnf_elem("zhub", estimate, "FT", yell);
// make sure that v_tip (omega*r) is below 0.7mach ~ 750ft/s
estimate = (750.0/Radius)/(2.0*M_PI) * 60.0; // 7160/Radius
NominalRPM = cnf_elem("nominalrpm", estimate, yell);
MinRPM = cnf_elem("minrpm", 1.0, silent);
MinRPM = Constrain(1.0, MinRPM, NominalRPM-1.0);
estimate = (xmain) ? 0.12 : 0.07; // guess solidity
estimate = estimate * M_PI*Radius/BladeNum;
BladeChord = cnf_elem("chord", estimate, "FT", yell);
LiftCurveSlope = cnf_elem("liftcurveslope", 6.0, yell); // "1/RAD"
estimate = sqr(BladeChord) * sqr(Radius) * 0.57;
BladeFlappingMoment = cnf_elem("flappingmoment", estimate, "SLUG*FT2", yell);
BladeFlappingMoment = Constrain(0.1, BladeFlappingMoment, 1e9);
BladeTwist = cnf_elem("twist", -0.17, "RAD", yell);
estimate = sqr(BladeChord) * BladeChord * 15.66; // might be really wrong!
BladeMassMoment = cnf_elem("massmoment", estimate, yell); // slug-ft
BladeMassMoment = Constrain(0.1, BladeMassMoment, 1e9);
TipLossB = cnf_elem("tiplossfactor", 0.98, silent);
estimate = 1.1 * BladeFlappingMoment * BladeNum;
PolarMoment = cnf_elem("polarmoment", estimate, "SLUG*FT2", silent);
PolarMoment = Constrain(0.1, PolarMoment, 1e9);
InflowLag = cnf_elem("inflowlag", 0.2, silent); // fixme, depends on size
estimate = (xmain) ? 0.0 : -0.06;
ShaftTilt = cnf_elem("shafttilt", estimate, "RAD", silent);
// ignore differences between teeter/hingeless/fully-articulated constructions
estimate = 0.05 * Radius;
HingeOffset = cnf_elem("hingeoffset", estimate, "FT", (xmain) ? silent : yell);
CantAngleD3 = cnf_elem("cantangle", 0.0, "RAD", silent);
// derived parameters
// precalc often used powers
R[0]=1.0; R[1]=Radius; R[2]=R[1]*R[1]; R[3]=R[2]*R[1]; R[4]=R[3]*R[1];
B[0]=1.0; B[1]=TipLossB; B[2]=B[1]*B[1]; B[3]=B[2]*B[1]; B[4]=B[3]*B[1]; B[5]=B[4]*B[1];
LockNumberByRho = LiftCurveSlope * BladeChord * R[4] / BladeFlappingMoment;
solidity = BladeNum * BladeChord / (M_PI * Radius);
// use simple orientations at the moment
if (flags & eTail) { // axis parallel to Y_body
theta_shaft = 0.0; // no tilt
phi_shaft = 0.5*M_PI;
// opposite direction if main rotor is spinning CW
if (xmain && (xmain->flags & eRotCW) ) {
phi_shaft = -phi_shaft;
}
} else { // more or less upright
theta_shaft = ShaftTilt;
phi_shaft = 0.0;
}
// setup Shaft-Body transforms, see /SH79/ eqn(17,18)
double st = sin(theta_shaft);
double ct = cos(theta_shaft);
double sp = sin(phi_shaft);
double cp = cos(phi_shaft);
ShaftToBody.InitMatrix( ct, st*sp, st*cp,
0.0, cp, -sp,
-st, ct*sp, ct*cp );
BodyToShaft = ShaftToBody.Inverse();
// misc defaults
nu = 0.001; // help the flow solver by providing some moving molecules
return;
}
FGPiston::FGPiston(FGFDMExec* exec, Element* el, int engine_number, struct Inputs& input)
: FGEngine(exec, el, engine_number, input),
R_air(287.3), // Gas constant for air J/Kg/K
rho_fuel(800), // estimate
calorific_value_fuel(47.3e6), // J/Kg
Cp_air(1005), // Specific heat (constant pressure) J/Kg/K
Cp_fuel(1700),
standard_pressure(101320.73)
{
Element *table_element;
string token;
string name="";
// Defaults and initializations
Type = etPiston;
// These items are read from the configuration file
// Defaults are from a Lycoming O-360, more or less
Cycles = 4;
IdleRPM = 600;
MaxRPM = 2800;
Displacement = 360;
SparkFailDrop = 1.0;
MaxHP = 200;
MinManifoldPressure_inHg = 6.5;
MaxManifoldPressure_inHg = 28.5;
ManifoldPressureLag=1.0;
ISFC = -1;
volumetric_efficiency = 0.85;
Bore = 5.125;
Stroke = 4.375;
Cylinders = 4;
CylinderHeadMass = 2; //kg
CompressionRatio = 8.5;
Z_airbox = -999;
Ram_Air_Factor = 1;
PeakMeanPistonSpeed_fps = 100;
FMEPDynamic= 18400;
FMEPStatic = 46500;
Cooling_Factor = 0.5144444;
StaticFriction_HP = 1.5;
StarterGain = 1.;
StarterTorque = -1.;
StarterRPM = -1.;
// These are internal program variables
Lookup_Combustion_Efficiency = 0;
Mixture_Efficiency_Correlation = 0;
crank_counter = 0;
Magnetos = 0;
minMAP = 21950;
maxMAP = 96250;
ResetToIC();
// Supercharging
BoostSpeeds = 0; // Default to no supercharging
BoostSpeed = 0;
Boosted = false;
BoostOverride = 0;
BoostManual = 0;
bBoostOverride = false;
bTakeoffBoost = false;
TakeoffBoost = 0.0; // Default to no extra takeoff-boost
int i;
for (i=0; i<FG_MAX_BOOST_SPEEDS; i++) {
RatedBoost[i] = 0.0;
RatedPower[i] = 0.0;
RatedAltitude[i] = 0.0;
BoostMul[i] = 1.0;
RatedMAP[i] = 100000;
RatedRPM[i] = 2500;
TakeoffMAP[i] = 100000;
}
for (i=0; i<FG_MAX_BOOST_SPEEDS-1; i++) {
BoostSwitchAltitude[i] = 0.0;
BoostSwitchPressure[i] = 0.0;
}
// Read inputs from engine data file where present.
if (el->FindElement("minmp"))
MinManifoldPressure_inHg = el->FindElementValueAsNumberConvertTo("minmp","INHG");
if (el->FindElement("maxmp"))
MaxManifoldPressure_inHg = el->FindElementValueAsNumberConvertTo("maxmp","INHG");
if (el->FindElement("man-press-lag"))
ManifoldPressureLag = el->FindElementValueAsNumber("man-press-lag");
if (el->FindElement("displacement"))
Displacement = el->FindElementValueAsNumberConvertTo("displacement","IN3");
if (el->FindElement("maxhp"))
MaxHP = el->FindElementValueAsNumberConvertTo("maxhp","HP");
if (el->FindElement("static-friction"))
StaticFriction_HP = el->FindElementValueAsNumberConvertTo("static-friction","HP");
if (el->FindElement("sparkfaildrop"))
SparkFailDrop = Constrain(0, 1 - el->FindElementValueAsNumber("sparkfaildrop"), 1);
if (el->FindElement("cycles"))
Cycles = el->FindElementValueAsNumber("cycles");
if (el->FindElement("idlerpm"))
IdleRPM = el->FindElementValueAsNumber("idlerpm");
if (el->FindElement("maxrpm"))
MaxRPM = el->FindElementValueAsNumber("maxrpm");
if (el->FindElement("maxthrottle"))
MaxThrottle = el->FindElementValueAsNumber("maxthrottle");
if (el->FindElement("minthrottle"))
MinThrottle = el->FindElementValueAsNumber("minthrottle");
if (el->FindElement("bsfc"))
ISFC = el->FindElementValueAsNumberConvertTo("bsfc", "LBS/HP*HR");
if (el->FindElement("volumetric-efficiency"))
volumetric_efficiency = el->FindElementValueAsNumber("volumetric-efficiency");
if (el->FindElement("compression-ratio"))
CompressionRatio = el->FindElementValueAsNumber("compression-ratio");
if (el->FindElement("bore"))
Bore = el->FindElementValueAsNumberConvertTo("bore","IN");
if (el->FindElement("stroke"))
Stroke = el->FindElementValueAsNumberConvertTo("stroke","IN");
if (el->FindElement("cylinders"))
Cylinders = el->FindElementValueAsNumber("cylinders");
if (el->FindElement("cylinder-head-mass"))
CylinderHeadMass = el->FindElementValueAsNumberConvertTo("cylinder-head-mass","KG");
if (el->FindElement("air-intake-impedance-factor"))
Z_airbox = el->FindElementValueAsNumber("air-intake-impedance-factor");
if (el->FindElement("ram-air-factor"))
Ram_Air_Factor = el->FindElementValueAsNumber("ram-air-factor");
if (el->FindElement("cooling-factor"))
Cooling_Factor = el->FindElementValueAsNumber("cooling-factor");
if (el->FindElement("starter-rpm"))
StarterRPM = el->FindElementValueAsNumber("starter-rpm");
if (el->FindElement("starter-torque"))
StarterTorque = el->FindElementValueAsNumber("starter-torque");
if (el->FindElement("dynamic-fmep"))
FMEPDynamic= el->FindElementValueAsNumberConvertTo("dynamic-fmep","PA");
if (el->FindElement("static-fmep"))
FMEPStatic = el->FindElementValueAsNumberConvertTo("static-fmep","PA");
if (el->FindElement("peak-piston-speed"))
PeakMeanPistonSpeed_fps = el->FindElementValueAsNumber("peak-piston-speed");
if (el->FindElement("numboostspeeds")) { // Turbo- and super-charging parameters
BoostSpeeds = (int)el->FindElementValueAsNumber("numboostspeeds");
if (el->FindElement("boostoverride"))
BoostOverride = (int)el->FindElementValueAsNumber("boostoverride");
if (el->FindElement("boostmanual"))
BoostManual = (int)el->FindElementValueAsNumber("boostmanual");
if (el->FindElement("takeoffboost"))
TakeoffBoost = el->FindElementValueAsNumberConvertTo("takeoffboost", "PSI");
if (el->FindElement("ratedboost1"))
RatedBoost[0] = el->FindElementValueAsNumberConvertTo("ratedboost1", "PSI");
if (el->FindElement("ratedboost2"))
RatedBoost[1] = el->FindElementValueAsNumberConvertTo("ratedboost2", "PSI");
if (el->FindElement("ratedboost3"))
RatedBoost[2] = el->FindElementValueAsNumberConvertTo("ratedboost3", "PSI");
if (el->FindElement("ratedpower1"))
RatedPower[0] = el->FindElementValueAsNumberConvertTo("ratedpower1", "HP");
if (el->FindElement("ratedpower2"))
RatedPower[1] = el->FindElementValueAsNumberConvertTo("ratedpower2", "HP");
if (el->FindElement("ratedpower3"))
RatedPower[2] = el->FindElementValueAsNumberConvertTo("ratedpower3", "HP");
if (el->FindElement("ratedrpm1"))
RatedRPM[0] = el->FindElementValueAsNumber("ratedrpm1");
if (el->FindElement("ratedrpm2"))
RatedRPM[1] = el->FindElementValueAsNumber("ratedrpm2");
if (el->FindElement("ratedrpm3"))
RatedRPM[2] = el->FindElementValueAsNumber("ratedrpm3");
if (el->FindElement("ratedaltitude1"))
RatedAltitude[0] = el->FindElementValueAsNumberConvertTo("ratedaltitude1", "FT");
if (el->FindElement("ratedaltitude2"))
RatedAltitude[1] = el->FindElementValueAsNumberConvertTo("ratedaltitude2", "FT");
if (el->FindElement("ratedaltitude3"))
RatedAltitude[2] = el->FindElementValueAsNumberConvertTo("ratedaltitude3", "FT");
}
while((table_element = el->FindNextElement("table")) != 0) {
name = table_element->GetAttributeValue("name");
try {
if (name == "COMBUSTION") {
Lookup_Combustion_Efficiency = new FGTable(PropertyManager, table_element);
} else if (name == "MIXTURE") {
Mixture_Efficiency_Correlation = new FGTable(PropertyManager, table_element);
} else {
cerr << "Unknown table type: " << name << " in piston engine definition." << endl;
}
} catch (std::string str) {
throw("Error loading piston engine table:" + name + ". " + str);
}
}
volumetric_efficiency_reduced = volumetric_efficiency;
if(StarterRPM < 0.) StarterRPM = 2*IdleRPM;
if(StarterTorque < 0)
StarterTorque = (MaxHP)*0.4; //just a wag.
displacement_SI = Displacement * in3tom3;
RatedMeanPistonSpeed_fps = ( MaxRPM * Stroke) / (360); // AKA 2 * (RPM/60) * ( Stroke / 12) or 2NS
// Create IFSC to match the engine if not provided
if (ISFC < 0) {
double pmep = 29.92 - MaxManifoldPressure_inHg;
pmep *= inhgtopa * volumetric_efficiency;
double fmep = (FMEPDynamic * RatedMeanPistonSpeed_fps * fttom + FMEPStatic);
double hp_loss = ((pmep + fmep) * displacement_SI * MaxRPM)/(Cycles*22371);
ISFC = ( 1.1*Displacement * MaxRPM * volumetric_efficiency *(MaxManifoldPressure_inHg / 29.92) ) / (9411 * (MaxHP+hp_loss-StaticFriction_HP));
// cout <<"FMEP: "<< fmep <<" PMEP: "<< pmep << " hp_loss: " <<hp_loss <<endl;
}
if ( MaxManifoldPressure_inHg > 29.9 ) { // Don't allow boosting with a bogus number
MaxManifoldPressure_inHg = 29.9;
}
minMAP = MinManifoldPressure_inHg * inhgtopa; // inHg to Pa
maxMAP = MaxManifoldPressure_inHg * inhgtopa;
// For throttle
/*
* Pm = ( Ze / ( Ze + Zi + Zt ) ) * Pa
* Where:
* Pm = Manifold Pressure
* Pa = Ambient Pressre
* Ze = engine impedance, Ze is effectively 1 / Mean Piston Speed
* Zi = airbox impedance
* Zt = throttle impedance
*
* For the calculation below throttle is fully open or Zt = 0
*
*
*
*/
if(Z_airbox < 0.0){
double Ze=PeakMeanPistonSpeed_fps/RatedMeanPistonSpeed_fps; // engine impedence
Z_airbox = (standard_pressure *Ze / maxMAP) - Ze; // impedence of airbox
}
// Constant for Throttle impedence
Z_throttle=(PeakMeanPistonSpeed_fps/((IdleRPM * Stroke) / 360))*(standard_pressure/minMAP - 1) - Z_airbox;
// Z_throttle=(MaxRPM/IdleRPM )*(standard_pressure/minMAP+2); // Constant for Throttle impedence
// Default tables if not provided in the configuration file
if(Lookup_Combustion_Efficiency == 0) {
// First column is thi, second is neta (combustion efficiency)
Lookup_Combustion_Efficiency = new FGTable(12);
*Lookup_Combustion_Efficiency << 0.00 << 0.980;
*Lookup_Combustion_Efficiency << 0.90 << 0.980;
*Lookup_Combustion_Efficiency << 1.00 << 0.970;
*Lookup_Combustion_Efficiency << 1.05 << 0.950;
*Lookup_Combustion_Efficiency << 1.10 << 0.900;
*Lookup_Combustion_Efficiency << 1.15 << 0.850;
*Lookup_Combustion_Efficiency << 1.20 << 0.790;
*Lookup_Combustion_Efficiency << 1.30 << 0.700;
*Lookup_Combustion_Efficiency << 1.40 << 0.630;
*Lookup_Combustion_Efficiency << 1.50 << 0.570;
*Lookup_Combustion_Efficiency << 1.60 << 0.525;
*Lookup_Combustion_Efficiency << 2.00 << 0.345;
}
// First column is Fuel/Air Ratio, second is neta (mixture efficiency)
if( Mixture_Efficiency_Correlation == 0) {
Mixture_Efficiency_Correlation = new FGTable(15);
*Mixture_Efficiency_Correlation << 0.05000 << 0.00000;
*Mixture_Efficiency_Correlation << 0.05137 << 0.00862;
*Mixture_Efficiency_Correlation << 0.05179 << 0.21552;
*Mixture_Efficiency_Correlation << 0.05430 << 0.48276;
*Mixture_Efficiency_Correlation << 0.05842 << 0.70690;
*Mixture_Efficiency_Correlation << 0.06312 << 0.83621;
*Mixture_Efficiency_Correlation << 0.06942 << 0.93103;
*Mixture_Efficiency_Correlation << 0.07786 << 1.00000;
*Mixture_Efficiency_Correlation << 0.08845 << 1.00000;
*Mixture_Efficiency_Correlation << 0.09270 << 0.98276;
*Mixture_Efficiency_Correlation << 0.10120 << 0.93103;
*Mixture_Efficiency_Correlation << 0.11455 << 0.72414;
*Mixture_Efficiency_Correlation << 0.12158 << 0.45690;
*Mixture_Efficiency_Correlation << 0.12435 << 0.23276;
*Mixture_Efficiency_Correlation << 0.12500 << 0.00000;
}
string property_name, base_property_name;
base_property_name = CreateIndexedPropertyName("propulsion/engine", EngineNumber);
property_name = base_property_name + "/power-hp";
PropertyManager->Tie(property_name, &HP);
property_name = base_property_name + "/bsfc-lbs_hphr";
PropertyManager->Tie(property_name, &ISFC);
property_name = base_property_name + "/starter-norm";
PropertyManager->Tie(property_name, &StarterGain);
property_name = base_property_name + "/volumetric-efficiency";
PropertyManager->Tie(property_name, &volumetric_efficiency);
property_name = base_property_name + "/map-pa";
PropertyManager->Tie(property_name, &MAP);
property_name = base_property_name + "/map-inhg";
PropertyManager->Tie(property_name, &ManifoldPressure_inHg);
property_name = base_property_name + "/air-intake-impedance-factor";
PropertyManager->Tie(property_name, &Z_airbox);
property_name = base_property_name + "/ram-air-factor";
PropertyManager->Tie(property_name, &Ram_Air_Factor);
property_name = base_property_name + "/cooling-factor";
PropertyManager->Tie(property_name, &Cooling_Factor);
property_name = base_property_name + "/boost-speed";
PropertyManager->Tie(property_name, &BoostSpeed);
property_name = base_property_name + "/cht-degF";
PropertyManager->Tie(property_name, this, &FGPiston::getCylinderHeadTemp_degF);
property_name = base_property_name + "/oil-temperature-degF";
PropertyManager->Tie(property_name, this, &FGPiston::getOilTemp_degF);
property_name = base_property_name + "/oil-pressure-psi";
PropertyManager->Tie(property_name, this, &FGPiston::getOilPressure_psi);
property_name = base_property_name + "/egt-degF";
PropertyManager->Tie(property_name, this, &FGPiston::getExhaustGasTemp_degF);
// Set up and sanity-check the turbo/supercharging configuration based on the input values.
if (TakeoffBoost > RatedBoost[0]) bTakeoffBoost = true;
for (i=0; i<BoostSpeeds; ++i) {
bool bad = false;
if (RatedBoost[i] <= 0.0) bad = true;
if (RatedPower[i] <= 0.0) bad = true;
if (RatedAltitude[i] < 0.0) bad = true; // 0.0 is deliberately allowed - this corresponds to unregulated supercharging.
if (i > 0 && RatedAltitude[i] < RatedAltitude[i - 1]) bad = true;
if (bad) {
// We can't recover from the above - don't use this supercharger speed.
BoostSpeeds--;
// TODO - put out a massive error message!
break;
}
// Now sanity-check stuff that is recoverable.
if (i < BoostSpeeds - 1) {
if (BoostSwitchAltitude[i] < RatedAltitude[i]) {
// TODO - put out an error message
// But we can also make a reasonable estimate, as below.
BoostSwitchAltitude[i] = RatedAltitude[i] + 1000;
}
BoostSwitchPressure[i] = GetStdPressure100K(BoostSwitchAltitude[i]) * psftopa;
//cout << "BoostSwitchAlt = " << BoostSwitchAltitude[i] << ", pressure = " << BoostSwitchPressure[i] << '\n';
// Assume there is some hysteresis on the supercharger gear switch, and guess the value for now
BoostSwitchHysteresis = 1000;
}
// Now work out the supercharger pressure multiplier of this speed from the rated boost and altitude.
RatedMAP[i] = standard_pressure + RatedBoost[i] * 6895; // psi*6895 = Pa.
// Sometimes a separate BCV setting for takeoff or extra power is fitted.
if (TakeoffBoost > RatedBoost[0]) {
// Assume that the effect on the BCV is the same whichever speed is in use.
TakeoffMAP[i] = RatedMAP[i] + ((TakeoffBoost - RatedBoost[0]) * 6895);
bTakeoffBoost = true;
} else {
TakeoffMAP[i] = RatedMAP[i];
bTakeoffBoost = false;
}
BoostMul[i] = RatedMAP[i] / (GetStdPressure100K(RatedAltitude[i]) * psftopa);
}
if (BoostSpeeds > 0) {
Boosted = true;
BoostSpeed = 0;
}
bBoostOverride = (BoostOverride == 1 ? true : false);
bBoostManual = (BoostManual == 1 ? true : false);
Debug(0); // Call Debug() routine from constructor if needed
}
main(int argc, char *argv[])
{
InitializeConstrainer(argc,argv);
Constrain();
exit(0);
}
