Latest YASim changes.

src/FDM/YASim/Airplane.cpp

@@ -207,7 +207,8 @@ void Airplane::addVStab(Wing* vstab)
     _vstabs.add(vstab);
 }
 
-void Airplane::addFuselage(float* front, float* back, float width)
+void Airplane::addFuselage(float* front, float* back, float width,
+                           float taper, float mid)
 {
     Fuselage* f = new Fuselage();
     int i;
@@ -216,6 +217,8 @@ void Airplane::addFuselage(float* front, float* back, float width)
 	f->back[i]  = back[i];
     }
     f->width = width;
+    f->taper = taper;
+    f->mid = mid;
     _fuselages.add(f);
 }
 
@@ -358,12 +361,18 @@ float Airplane::compileWing(Wing* w)
     int i;
     for(i=0; i<w->numSurfaces(); i++) {
         Surface* s = (Surface*)w->getSurface(i);
+
+	float td = s->getTotalDrag();
+	s->setTotalDrag(td);
+
         _model.addSurface(s);
 
+        float mass = w->getSurfaceWeight(i);
+        mass = mass * Math::sqrt(mass);
         float pos[3];
         s->getPosition(pos);
-        _model.getBody()->addMass(w->getSurfaceWeight(i), pos);
+        _model.getBody()->addMass(mass, pos);
-        wgt += w->getSurfaceWeight(i);
+        wgt += mass;
     }
     return wgt;
 }
@@ -380,11 +389,22 @@ float Airplane::compileFuselage(Fuselage* f)
     int j;
     for(j=0; j<segs; j++) {
         float frac = (j+0.5) / segs;
+
+        float scale = 1;
+        if(frac < f->mid)
+            scale = f->taper+(1-f->taper) * (frac / f->mid);
+        else
+            scale = f->taper+(1-f->taper) * (frac - f->mid) / (1 - f->mid);
+
+        // Where are we?
         float pos[3];
         Math::mul3(frac, fwd, pos);
         Math::add3(f->back, pos, pos);
-        _model.getBody()->addMass(segWgt, pos);
+
-        wgt += segWgt;
+        // _Mass_ weighting goes as surface area^(3/2)
+        float mass = scale*segWgt * Math::sqrt(scale*segWgt);
+        _model.getBody()->addMass(mass, pos);
+        wgt += mass;
 
         // Make a Surface too
         Surface* s = new Surface();
@@ -392,7 +412,7 @@ float Airplane::compileFuselage(Fuselage* f)
 	float sideDrag = len/wid;
         s->setYDrag(sideDrag);
         s->setZDrag(sideDrag);
-        s->setTotalDrag(segWgt);
+        s->setTotalDrag(scale*segWgt);
 
         // FIXME: fails for fuselages aligned along the Y axis
         float o[9];

src/FDM/YASim/Airplane.hpp

@@ -32,7 +32,8 @@ public:
     void setTail(Wing* tail);
     void addVStab(Wing* vstab);
 
-    void addFuselage(float* front, float* back, float width);
+    void addFuselage(float* front, float* back, float width,
+                     float taper=1, float mid=0.5);
     int addTank(float* pos, float cap, float fuelDensity);
     void addGear(Gear* g, float transitionTime);
     void addThruster(Thruster* t, float mass, float* cg);
@@ -58,6 +59,7 @@ public:
     float getFuelDensity(int tank); // kg/m^3
 
     void compile(); // generate point masses & such, then solve
+    void stabilizeThrust();
 
     // Solution output values
     int getSolutionIterations();
@@ -70,7 +72,7 @@ public:
 private:
     struct Tank { float pos[3]; float cap; float fill;
 	          float density; int handle; };
-    struct Fuselage { float front[3], back[3], width; };
+    struct Fuselage { float front[3], back[3], width, taper, mid; };
     struct GearRec { Gear* gear; Surface* surf; float wgt; float time; };
     struct ThrustRec { Thruster* thruster;
 	               int handle; float cg[3]; float mass; };
@@ -85,7 +87,6 @@ private:
     float compileWing(Wing* w);
     float compileFuselage(Fuselage* f);
     void compileGear(GearRec* gr);
-    void stabilizeThrust();
     void applyDragFactor(float factor);
     void applyLiftRatio(float factor);
     float clamp(float val, float min, float max);

src/FDM/YASim/Atmosphere.cpp

@@ -35,6 +35,9 @@ float Atmosphere::data[][4] = {{ 0,     288.20, 101325, 1.22500 },
 // P in pascals (N/m^2), rho is kg/m^3, T in kelvin.
 const float R = 287.1;
 
+// Specific heat ratio for air, at "low" temperatures.  
+const float GAMMA = 1.4;
+
 float Atmosphere::getStdTemperature(float alt)
 {
     return getRecord(alt, 1);
@@ -95,7 +98,18 @@ float Atmosphere::calcDensity(float pressure, float temp)
 
 float Atmosphere::calcMach(float spd, float temp)
 {
-    return spd / Math::sqrt(1.4 * R * temp);
+    return spd / Math::sqrt(GAMMA * R * temp);
+}
+
+void Atmosphere::calcStaticAir(float p0, float t0, float d0, float v,
+                               float* pOut, float* tOut, float* dOut)
+{
+    const static float C0 = ((GAMMA-1)/(2*R*GAMMA));
+    const static float C1 = 1/(GAMMA-1);
+
+    *tOut = t0 + (v*v) * C0;
+    *dOut = d0 * Math::pow(*tOut / t0, C1);
+    *pOut = (*dOut) * R * (*tOut);
 }
 
 float Atmosphere::getRecord(float alt, int recNum)

src/FDM/YASim/Atmosphere.hpp

@@ -13,6 +13,13 @@ public:
     static float calcVEAS(float spd, float pressure, float temp);
     static float calcMach(float spd, float temp);
     static float calcDensity(float pressure, float temp);
+    
+    // Given ambient ("0") pressure/density/temperature values,
+    // calculate the properties of static air (air accelerated to the
+    // aircraft's speed) at a given velocity.  Includes
+    // compressibility, but not shock effects.
+    static void calcStaticAir(float p0, float t0, float d0, float v,
+                              float* pOut, float* tOut, float* dOut);
 
 private:
     static float getRecord(float alt, int idx);

src/FDM/YASim/ControlMap.cpp

@@ -1,6 +1,7 @@
 #include "Jet.hpp"
 #include "Thruster.hpp"
 #include "PropEngine.hpp"
+#include "PistonEngine.hpp"
 #include "Gear.hpp"
 #include "Wing.hpp"
 #include "Math.hpp"
@@ -19,11 +20,8 @@ ControlMap::~ControlMap()
 	delete v;
     }
 
-    for(i=0; i<_outputs.size(); i++) {
+    for(i=0; i<_outputs.size(); i++)
-	OutRec* o = (OutRec*)_outputs.get(i);
+	delete (OutRec*)_outputs.get(i);
-	delete[] o->values;
-	delete o;
-    }
 }
 
 int ControlMap::newInput()
@@ -32,6 +30,21 @@ int ControlMap::newInput()
     return _inputs.add(v);
 }
 
+void ControlMap::addMapping(int input, int type, void* object, int options,
+			    float src0, float src1, float dst0, float dst1)
+{
+    addMapping(input, type, object, options);
+
+    // The one we just added is last in the list (ugly, awful hack!)
+    Vector* maps = (Vector*)_inputs.get(input);
+    MapRec* m = (MapRec*)maps->get(maps->size() - 1);
+
+    m->src0 = src0;
+    m->src1 = src1;
+    m->dst0 = dst0;
+    m->dst1 = dst1;
+}
+
 void ControlMap::addMapping(int input, int type, void* object, int options)
 {
     // See if the output object already exists
@@ -50,25 +63,22 @@ void ControlMap::addMapping(int input, int type, void* object, int options)
 	out = new OutRec();
 	out->type = type;
 	out->object = object;
-	out->n = 0;
-	out->values = 0;
 	_outputs.add(out);
     }
-
+    
-    // Make space for the new input value
-    int idx = out->n++;
-    delete[] out->values;
-    out->values = new float[out->n];
-
-    // Add the new option tag
-    out->options.add((void*)options);
-
     // Make a new input record
     MapRec* map = new MapRec();
     map->out = out;
-    map->idx = idx;
+    map->opt = options;
+    map->idx = out->maps.add(map);
 
-    // And add it to the approproate vector.
+    // The default ranges differ depending on type!
+    map->src1 = map->dst1 = 1;
+    map->src0 = map->dst0 = 0;
+    if(type==FLAP0 || type==FLAP1 || type==STEER)
+	map->src0 = map->dst0 = -1;
+
+    // And add it to the approproate vectors.
     Vector* maps = (Vector*)_inputs.get(input);
     maps->add(map);
 }
@@ -76,22 +86,29 @@ void ControlMap::addMapping(int input, int type, void* object, int options)
 void ControlMap::reset()
 {
     // Set all the values to zero
-    int i;
+    for(int i=0; i<_outputs.size(); i++) {
-    for(i=0; i<_outputs.size(); i++) {
 	OutRec* o = (OutRec*)_outputs.get(i);
-	int j;
+	for(int j=0; j<o->maps.size(); j++)
-	for(j=0; j<o->n; j++)
+	    ((MapRec*)o->maps.get(j))->val = 0;
-	    o->values[j] = 0;
     }
 }
 
-void ControlMap::setInput(int input, float value)
+void ControlMap::setInput(int input, float val)
 {
     Vector* maps = (Vector*)_inputs.get(input);
-    int i;
+    for(int i=0; i<maps->size(); i++) {
-    for(i=0; i<maps->size(); i++) {
+	MapRec* m = (MapRec*)maps->get(i);
-	MapRec* map = (MapRec*)maps->get(i);
+
-	map->out->values[map->idx] = value;
+	float val2 = val;
+
+	// Do the scaling operation.  Clamp to [src0:src1], rescale to
+	// [0:1] within that range, then map to [dst0:dst1].
+	if(val2 < m->src0) val2 = m->src0;
+	if(val2 > m->src1) val2 = m->src1;
+	val2 = (val2 - m->src0) / (m->src1 - m->src0);
+	val2 = m->dst0 + val2 * (m->dst1 - m->dst0);
+
+	m->val = val2;
     }
 }
 
@@ -105,15 +122,16 @@ void ControlMap::applyControls()
 	// control axes like ailerons.
 	float lval = 0, rval = 0;
 	int i;
-	for(i=0; i<o->n; i++) {
+	for(i=0; i<o->maps.size(); i++) {
-	    float val = o->values[i];
+	    MapRec* m = (MapRec*)o->maps.get(i);
-	    int opt = (int)o->options.get(i);
+	    float val = m->val;
-	    if(opt & OPT_SQUARE)
+
+	    if(m->opt & OPT_SQUARE)
 		val = val * Math::abs(val);
- 	    if(opt & OPT_INVERT)
+ 	    if(m->opt & OPT_INVERT)
 		val = -val;
 	    lval += val;
-	    if(opt & OPT_SPLIT)
+	    if(m->opt & OPT_SPLIT)
 		rval -= val;
 	    else
 		rval += val;
@@ -125,6 +143,7 @@ void ControlMap::applyControls()
 	case MIXTURE:  ((Thruster*)obj)->setMixture(lval);     break;
 	case ADVANCE:  ((PropEngine*)obj)->setAdvance(lval);   break;
 	case REHEAT:   ((Jet*)obj)->setReheat(lval);           break;
+	case VECTOR:   ((Jet*)obj)->setRotation(lval);         break;
 	case BRAKE:    ((Gear*)obj)->setBrake(lval);           break;
 	case STEER:    ((Gear*)obj)->setRotation(lval);        break;
 	case EXTEND:   ((Gear*)obj)->setExtension(lval);       break;
@@ -132,6 +151,9 @@ void ControlMap::applyControls()
 	case FLAP0:    ((Wing*)obj)->setFlap0(lval, rval);     break;
 	case FLAP1:    ((Wing*)obj)->setFlap1(lval, rval);     break;
 	case SPOILER:  ((Wing*)obj)->setSpoiler(lval, rval);   break;
+	case BOOST:
+	    ((Thruster*)obj)->getPistonEngine()->setBoost(lval);
+	    break;
 	}
     }
 }

src/FDM/YASim/ControlMap.hpp

@@ -11,7 +11,8 @@ public:
 
     enum OutputType { THROTTLE, MIXTURE, ADVANCE, REHEAT, PROP,
 		      BRAKE, STEER, EXTEND,
-		      INCIDENCE, FLAP0, FLAP1, SLAT, SPOILER };
+		      INCIDENCE, FLAP0, FLAP1, SLAT, SPOILER, VECTOR,
+                      BOOST };
 
     enum { OPT_SPLIT  = 0x01,
            OPT_INVERT = 0x02,
@@ -26,6 +27,12 @@ public:
     // of object!
     void addMapping(int input, int output, void* object, int options=0);
 
+    // An additional form to specify a mapping range.  Input values
+    // outside of [src0:src1] are clamped, and are then mapped to
+    // [dst0:dst1] before being set on the object.
+    void addMapping(int input, int output, void* object, int options,
+		    float src0, float src1, float dst0, float dst1);
+
     // Resets our accumulated input values.  Call before any
     // setInput() invokations.
     void reset();
@@ -38,9 +45,9 @@ public:
     void applyControls();
 
 private:
-    struct OutRec { int type; void* object; int n;
+    struct OutRec { int type; void* object; Vector maps; };
-	            float* values; Vector options; };
+    struct MapRec  { OutRec* out; int idx; int opt; float val;
-    struct MapRec  { OutRec* out; int idx; };
+                     float src0; float src1; float dst0; float dst1; };
 
     // A list of (sub)Vectors containing a bunch of MapRec objects for
     // each input handle.

src/FDM/YASim/FGFDM.cpp

@@ -4,6 +4,7 @@
 #include <Main/fg_props.hxx>
 
 #include "Jet.hpp"
+#include "SimpleJet.hpp"
 #include "Gear.hpp"
 #include "Atmosphere.hpp"
 #include "PropEngine.hpp"
@@ -23,6 +24,8 @@ static const float LBS2KG = 0.45359237;
 static const float CM2GALS = 264.172037284;
 static const float HP2W = 745.700;
 static const float INHG2PA = 3386.389;
+static const float K2DEGF = 1.8;
+static const float CIN2CM = 1.6387064e-5;
 
 // Stubs, so that this can be compiled without the FlightGear
 // binary.  What's the best way to handle this?
@@ -43,16 +46,10 @@ FGFDM::~FGFDM()
 	delete[] a->name;
 	delete a;
     }
-    for(i=0; i<_pistons.size(); i++) {
+    for(i=0; i<_thrusters.size(); i++) {
-	EngRec* er = (EngRec*)_pistons.get(i);
+	EngRec* er = (EngRec*)_thrusters.get(i);
 	delete[] er->prefix;
-	delete (PropEngine*)er->eng;
+	delete er->eng;
-	delete er;
-    }
-    for(i=0; i<_jets.size(); i++) {
-	EngRec* er = (EngRec*)_pistons.get(i);
-	delete[] er->prefix;
-	delete (Jet*)er->eng;
 	delete er;
     }
     for(i=0; i<_weights.size(); i++) {
@@ -77,12 +74,8 @@ Airplane* FGFDM::getAirplane()
 
 void FGFDM::init()
 {
-    // We don't want to use these ties (we set the values ourselves)
-    fgUntie("/consumables/fuel/tank[0]/level-gal_us");
-    fgUntie("/consumables/fuel/tank[1]/level-gal_us");
-
     // Allows the user to start with something other than full fuel
-    _airplane.setFuelFraction(fgGetFloat("/yasim/fuel-fraction", 1));
+    _airplane.setFuelFraction(fgGetFloat("/sim/fuel-fraction", 1));
 
     // This has a nasty habit of being false at startup.  That's not
     // good.
@@ -122,6 +115,15 @@ void FGFDM::startElement(const char* name, const XMLAttributes &atts)
 	_airplane.addVStab(parseWing(a, name));
     } else if(eq(name, "propeller")) {
 	parsePropeller(a);
+    } else if(eq(name, "thruster")) {
+	SimpleJet* j = new SimpleJet();
+	_currObj = j;
+	v[0] = attrf(a, "x"); v[1] = attrf(a, "y"); v[2] = attrf(a, "z");
+	j->setPosition(v);
+	_airplane.addThruster(j, 0, v);
+	v[0] = attrf(a, "vx"); v[1] = attrf(a, "vy"); v[2] = attrf(a, "vz");
+	j->setDirection(v);
+	j->setThrust(attrf(a, "thrust") * LBS2N);
     } else if(eq(name, "jet")) {
 	Jet* j = new Jet();
 	_currObj = j;
@@ -129,15 +131,29 @@ void FGFDM::startElement(const char* name, const XMLAttributes &atts)
 	v[1] = attrf(a, "y");
 	v[2] = attrf(a, "z");
 	float mass = attrf(a, "mass") * LBS2KG;
-	j->setDryThrust(attrf(a, "thrust") * LBS2N);
+	j->setMaxThrust(attrf(a, "thrust") * LBS2N,
-	j->setReheatThrust(attrf(a, "afterburner", 0) * LBS2N);
+			attrf(a, "afterburner", 0) * LBS2N);
+	j->setVectorAngle(attrf(a, "rotate", 0) * DEG2RAD);
+
+ 	float n1min = attrf(a, "n1-idle", 55);
+	float n1max = attrf(a, "n1-max", 102);
+ 	float n2min = attrf(a, "n2-idle", 73);
+	float n2max = attrf(a, "n2-max", 103);
+	j->setRPMs(n1min, n1max, n2min, n2max);
+
+	if(a->hasAttribute("tsfc")) j->setTSFC(attrf(a, "tsfc"));
+	if(a->hasAttribute("egt"))  j->setEGT(attrf(a, "egt"));
+	if(a->hasAttribute("epr"))  j->setEPR(attrf(a, "epr"));
+	if(a->hasAttribute("exhaust-speed"))
+	    j->setVMax(attrf(a, "exhaust-speed") * KTS2MPS);
+	
 	j->setPosition(v);
 	_airplane.addThruster(j, mass, v);
 	sprintf(buf, "/engines/engine[%d]", _nextEngine++);
 	EngRec* er = new EngRec();
 	er->eng = j;
 	er->prefix = dup(buf);
-	_jets.add(er);
+	_thrusters.add(er);
     } else if(eq(name, "gear")) {
 	Gear* g = new Gear();
 	_currObj = g;
@@ -151,6 +167,8 @@ void FGFDM::startElement(const char* name, const XMLAttributes &atts)
 	g->setCompression(v);
 	g->setStaticFriction(attrf(a, "sfric", 0.8));
 	g->setDynamicFriction(attrf(a, "dfric", 0.7));
+	if(a->hasAttribute("castering"))
+	    g->setCastering(true);
         float transitionTime = attrf(a, "retract-time", 0);
 	_airplane.addGear(g, transitionTime);
     } else if(eq(name, "fuselage")) {
@@ -161,14 +179,16 @@ void FGFDM::startElement(const char* name, const XMLAttributes &atts)
 	b[0] = attrf(a, "bx");
 	b[1] = attrf(a, "by");
 	b[2] = attrf(a, "bz");
-	_airplane.addFuselage(v, b, attrf(a, "width"));
+        float taper = attrf(a, "taper", 1);
+        float mid = attrf(a, "midpoint", 0.5);
+	_airplane.addFuselage(v, b, attrf(a, "width"), taper, mid);
     } else if(eq(name, "tank")) {
 	v[0] = attrf(a, "x");
 	v[1] = attrf(a, "y");
 	v[2] = attrf(a, "z");
 	float density = 6.0; // gasoline, in lbs/gal
 	if(a->hasAttribute("jet")) density = 6.72; 
-	density *= LBS2KG/CM2GALS;
+	density *= LBS2KG*CM2GALS;
 	_airplane.addTank(v, attrf(a, "capacity") * LBS2KG, density);
     } else if(eq(name, "ballast")) {
 	v[0] = attrf(a, "x");
@@ -213,10 +233,17 @@ void FGFDM::startElement(const char* name, const XMLAttributes &atts)
 	    opt |= a->hasAttribute("split") ? ControlMap::OPT_SPLIT : 0;
 	    opt |= a->hasAttribute("invert") ? ControlMap::OPT_INVERT : 0;
 	    opt |= a->hasAttribute("square") ? ControlMap::OPT_SQUARE : 0;
-	    _airplane.getControlMap()->addMapping(parseAxis(axis),
+
-						  parseOutput(output),
+	    ControlMap* cm = _airplane.getControlMap();
-						  _currObj,
+	    if(a->hasAttribute("src0")) {
-						  opt);
+		cm->addMapping(parseAxis(axis), parseOutput(output),
+			       _currObj, opt,
+			       attrf(a, "src0"), attrf(a, "src1"), 
+			       attrf(a, "dst0"), attrf(a, "dst1"));
+	    } else {
+		cm->addMapping(parseAxis(axis), parseOutput(output),
+			       _currObj, opt);
+	    }
 	} else {
 	    // assert: must be under a "cruise" or "approach" tag
 	    float value = attrf(a, "value", 0);
@@ -257,29 +284,52 @@ void FGFDM::setOutputProperties()
 {
     char buf[256];
     int i;
+    float fuelDensity = 718.95; // default to gasoline: ~6 lb/gal
     for(i=0; i<_airplane.numTanks(); i++) {
+        fuelDensity = _airplane.getFuelDensity(i);
 	sprintf(buf, "/consumables/fuel/tank[%d]/level-gal_us", i);
-	fgSetFloat(buf,
+	fgSetFloat(buf, CM2GALS*_airplane.getFuel(i)/fuelDensity);
-		   CM2GALS*_airplane.getFuel(i)/_airplane.getFuelDensity(i));
     }
 
-    for(i=0; i<_pistons.size(); i++) {
+    for(i=0; i<_thrusters.size(); i++) {
-	EngRec* er = (EngRec*)_pistons.get(i);
+	EngRec* er = (EngRec*)_thrusters.get(i);
-	PropEngine* p = (PropEngine*)er->eng;
+        Thruster* t = er->eng;
-
-	sprintf(buf, "%s/rpm", er->prefix);
-	fgSetFloat(buf, p->getOmega() / RPM2RAD);
 
 	sprintf(buf, "%s/fuel-flow-gph", er->prefix);
-	fgSetFloat(buf, p->getFuelFlow() * (3600*2.2/5)); // FIXME, wrong
+	fgSetFloat(buf, (t->getFuelFlow()/fuelDensity) * 3600 * CM2GALS);
-    }
 
-    for(i=0; i<_jets.size(); i++) {
+	if(t->getPropEngine()) {
-	EngRec* er = (EngRec*)_jets.get(i);
+            PropEngine* p = t->getPropEngine();
-	Jet* j = (Jet*)er->eng;
+
-	
+            sprintf(buf, "%s/rpm", er->prefix);
-	sprintf(buf, "%s/fuel-flow-gph", er->prefix);
+            fgSetFloat(buf, p->getOmega() / RPM2RAD);
-	fgSetFloat(buf, j->getFuelFlow() * (3600*2.2/6)); // FIXME, wrong
+        }
+
+        if(t->getPistonEngine()) {
+            PistonEngine* p = t->getPistonEngine();
+	    
+            sprintf(buf, "%s/mp-osi", er->prefix);
+	    fgSetFloat(buf, p->getMP() * (1/INHG2PA));
+
+	    sprintf(buf, "%s/egt-degf", er->prefix);
+	    fgSetFloat(buf, p->getEGT() * K2DEGF + 459.4);
+        }
+
+        if(t->getJet()) {
+            Jet* j = t->getJet();
+
+            sprintf(buf, "%s/n1", er->prefix);
+            fgSetFloat(buf, j->getN1());
+
+            sprintf(buf, "%s/n2", er->prefix);
+            fgSetFloat(buf, j->getN2());
+
+            sprintf(buf, "%s/epr", er->prefix);
+            fgSetFloat(buf, j->getEPR());
+
+            sprintf(buf, "%s/egt-degf", er->prefix);
+            fgSetFloat(buf, j->getEGT() * K2DEGF + 459.4);
+        }
     }
 }
 
@@ -337,6 +387,12 @@ void FGFDM::parsePropeller(XMLAttributes* a)
     PropEngine* thruster = new PropEngine(prop, eng, moment);
     _airplane.addThruster(thruster, mass, cg);
 
+    if(a->hasAttribute("displacement"))
+        eng->setDisplacement(attrf(a, "displacement") * CIN2CM);
+
+    if(a->hasAttribute("compression"))
+        eng->setCompression(attrf(a, "compression"));        
+
     if(a->hasAttribute("turbo-mul")) {
         float mul = attrf(a, "turbo-mul");
         float mp = attrf(a, "wastegate-mp", 1e6) * INHG2PA;
@@ -360,7 +416,7 @@ void FGFDM::parsePropeller(XMLAttributes* a)
     EngRec* er = new EngRec();
     er->eng = thruster;
     er->prefix = dup(buf);
-    _pistons.add(er);
+    _thrusters.add(er);
 
     _currObj = thruster;
 }
@@ -391,6 +447,8 @@ int FGFDM::parseOutput(const char* name)
     if(eq(name, "MIXTURE"))   return ControlMap::MIXTURE;
     if(eq(name, "ADVANCE"))   return ControlMap::ADVANCE;
     if(eq(name, "REHEAT"))    return ControlMap::REHEAT;
+    if(eq(name, "BOOST"))     return ControlMap::BOOST;
+    if(eq(name, "VECTOR"))    return ControlMap::VECTOR;
     if(eq(name, "PROP"))      return ControlMap::PROP;
     if(eq(name, "BRAKE"))     return ControlMap::BRAKE;
     if(eq(name, "STEER"))     return ControlMap::STEER;
@@ -401,7 +459,7 @@ int FGFDM::parseOutput(const char* name)
     if(eq(name, "SLAT"))      return ControlMap::SLAT;
     if(eq(name, "SPOILER"))   return ControlMap::SPOILER;
     // error here...
-    return -1;
+    return *(int*)0;
 }
 
 void FGFDM::parseWeight(XMLAttributes* a)

src/FDM/YASim/FGFDM.hpp

@@ -19,6 +19,7 @@ public:
     ~FGFDM();
     void init();
     void iterate(float dt);
+    void getExternalInput(float dt=1e6);
 
     Airplane* getAirplane();
 
@@ -27,10 +28,9 @@ public:
 
 private:
     struct AxisRec { char* name; int handle; };
-    struct EngRec { char* prefix; void* eng; };
+    struct EngRec { char* prefix; Thruster* eng; };
     struct WeightRec { char* prop; float size; int handle; };
 
-    void getExternalInput(float dt);
     void setOutputProperties();
 
     Wing* parseWing(XMLAttributes* a, const char* name);
@@ -56,8 +56,7 @@ private:
     Vector _weights;
 
     // Engine types.  Contains an EngRec structure.
-    Vector _jets;
+    Vector _thrusters;
-    Vector _pistons;
 
     // Parsing temporaries
     void* _currObj;

src/FDM/YASim/Gear.cpp

@@ -16,6 +16,7 @@ Gear::Gear()
     _brake = 0;
     _rot = 0;
     _extension = 1;
+    _castering = false;
 }
 
 void Gear::setPosition(float* position)
@@ -65,6 +66,11 @@ void Gear::setExtension(float extension)
     _extension = Math::clamp(extension, 0, 1);
 }
 
+void Gear::setCastering(bool c)
+{
+    _castering = c;
+}
+
 void Gear::getPosition(float* out)
 {
     int i;
@@ -128,6 +134,11 @@ float Gear::getCompressFraction()
     return _frac;
 }
 
+bool Gear::getCastering()
+{
+    return _castering;
+}
+
 void Gear::calcForce(RigidBody* body, float* v, float* rot, float* ground)
 {
     // Init the return values
@@ -191,6 +202,10 @@ void Gear::calcForce(RigidBody* body, float* v, float* rot, float* ground)
     _wow = (fmag - damp) * -Math::dot3(cmpr, ground);
     Math::mul3(-_wow, ground, _force);
 
+    // Castering gear feel no force in the ground plane
+    if(_castering)
+	return;
+
     // Wheels are funky.  Split the velocity along the ground plane
     // into rolling and skidding components.  Assuming small angles,
     // we generate "forward" and "left" unit vectors (the compression
@@ -237,8 +252,8 @@ void Gear::calcForce(RigidBody* body, float* v, float* rot, float* ground)
 
 float Gear::calcFriction(float wgt, float v)
 {
-    // How slow is stopped?  50 cm/second?
+    // How slow is stopped?  10 cm/second?
-    const float STOP = 0.5;
+    const float STOP = 0.1;
     const float iSTOP = 1/STOP;
     v = Math::abs(v);
     if(v < STOP) return v*iSTOP * wgt * _sfric;

src/FDM/YASim/Gear.hpp

@@ -37,7 +37,8 @@ public:
     void setBrake(float brake);
     void setRotation(float rotation);
     void setExtension(float extension);
-    
+    void setCastering(bool castering);
+
     void getPosition(float* out);
     void getCompression(float* out);
     float getSpring();
@@ -47,6 +48,7 @@ public:
     float getBrake();
     float getRotation();
     float getExtension();
+    bool getCastering();
 
     // Takes a velocity of the aircraft relative to ground, a rotation
     // vector, and a ground plane (all specified in local coordinates)
@@ -63,6 +65,7 @@ public:
 private:
     float calcFriction(float wgt, float v);
 
+    bool _castering;
     float _pos[3];
     float _cmpr[3];
     float _spring;

src/FDM/YASim/Jet.cpp

@@ -5,25 +5,90 @@ namespace yasim {
 
 Jet::Jet()
 {
-    _rho0 = Atmosphere::getStdDensity(0);
+    _maxThrust = 0;
-    _thrust = 0;
+    _abFactor = 1;
-    _abThrust = 0;
     _reheat = 0;
+    _rotControl = 0;
+    _maxRot = 0;
+
+    // Initialize parameters for an early-ish subsonic turbojet.  More
+    // recent turbofans will typically have a lower vMax, epr0, and
+    // tsfc.
+    _vMax = 800;
+    _epr0 = 3.0;
+    _tsfc = 0.8;
+    _egt0 = 1050;
+    _n1Min = 55;
+    _n1Max = 102;
+    _n2Min = 73;
+    _n2Max = 103;
+    setSpooling(4); // 4 second spool time? s'bout right.
+
+    // And initialize to an engine that is idling
+    _n1 = _n1Min;
+    _n2 = _n2Min;
+
+    // And sanify the remaining junk, just in case.
+    _epr = 1;
+    _fuelFlow = 0;
+    _egt = 273;
+    _tempCorrect = 1;
+    _pressureCorrect = 1;
 }
 
 void Jet::stabilize()
 {
-    return; // no-op for now
+    // Just run it for an hour, there's no need to iterate given the
+    // algorithms used.
+    integrate(3600);
 }
 
-void Jet::setDryThrust(float thrust)
+void Jet::setMaxThrust(float thrust, float afterburner)
 {
-    _thrust = thrust;
+    _maxThrust = thrust;
+    if(afterburner == 0) _abFactor = 1;
+    else                 _abFactor = afterburner/thrust;
 }
 
-void Jet::setReheatThrust(float thrust)
+void Jet::setVMax(float spd)
 {
-    _abThrust = thrust;
+    _vMax = spd;
+}
+
+void Jet::setTSFC(float tsfc)
+{
+    _tsfc = tsfc;
+}
+
+void Jet::setRPMs(float idleN1, float maxN1, float idleN2, float maxN2)
+{
+    _n1Min = idleN1;
+    _n1Max = maxN1;
+    _n2Min = idleN2;
+    _n2Max = maxN2;
+}
+
+void Jet::setEGT(float takeoffEGT)
+{
+    _egt0 = takeoffEGT;
+}
+
+void Jet::setEPR(float takeoffEPR)
+{
+    _epr0 = takeoffEPR;
+}
+
+void Jet::setSpooling(float time)
+{
+    // 2.3 = -ln(0.1), i.e. x=2.3 is the 90% point we're defining
+    // The extra fudge factor is there because the N1 speed (which
+    // determines thrust) lags the N2 speed.
+    _decay = 1.5 * 2.3 / time;
+}
+
+void Jet::setVectorAngle(float angle)
+{
+    _maxRot = angle;
 }
 
 void Jet::setReheat(float reheat)
@@ -31,12 +96,108 @@ void Jet::setReheat(float reheat)
     _reheat = Math::clamp(reheat, 0, 1);
 }
 
+void Jet::setRotation(float rot)
+{
+    if(rot < 0) rot = 0;
+    if(rot > 1) rot = 1;
+    _rotControl = rot;
+}
+
+
+float Jet::getN1()
+{
+    return _n1 * _tempCorrect;
+}
+
+float Jet::getN2()
+{
+    return _n2 * _tempCorrect;
+}
+
+float Jet::getEPR()
+{
+    return _epr;
+}
+
+float Jet::getEGT()
+{
+    // Exactly zero means "off" -- return the ambient temperature
+    if(_egt == 0) return _temp;
+
+    return _egt * _tempCorrect * _tempCorrect;
+}
+
+float Jet::getFuelFlow()
+{
+    return _fuelFlow * _pressureCorrect;
+}
+
+void Jet::integrate(float dt)
+{
+    // Sea-level values
+    const static float P0 = Atmosphere::getStdPressure(0);
+    const static float T0 = Atmosphere::getStdTemperature(0);
+    const static float D0 = Atmosphere::getStdDensity(0);
+
+    float speed = -Math::dot3(_wind, _dir);
+
+    float statT, statP, statD;
+    Atmosphere::calcStaticAir(_pressure, _temp, _rho, speed,
+                              &statP, &statT, &statD);
+    _pressureCorrect = statP/P0;
+    _tempCorrect = Math::sqrt(statT/T0);
+
+    // Linearly taper maxThrust to zero at vMax
+    float vCorr = 1 - (speed/_vMax);
+
+    float maxThrust = _maxThrust * vCorr * (statD/D0);
+    _thrust = maxThrust * _throttle;
+
+    // Now get a "beta" (i.e. EPR - 1) value.  The output values are
+    // expressed as functions of beta.
+    float ibeta0 = 1/(_epr0 - 1);
+    float betaTarget = (_epr0 - 1) * (_thrust/_maxThrust) * (P0/_pressure)
+	* (_temp/statT);
+    float n2Target = _n2Min + (betaTarget*ibeta0) * (_n2Max - _n2Min);
+
+    // Note that this "first" beta value is used to compute a target
+    // for N2 only Integrate the N2 speed and back-calculate a beta1
+    // target.  The N1 speed will seek to this.
+    _n2 = (_n2 + dt*_decay * n2Target) / (1 + dt*_decay);
+
+    float betaN2 = (_epr0-1) * (_n2 - _n2Min) / (_n2Max - _n2Min);
+    float n1Target = _n1Min + betaN2*ibeta0 * (_n1Max - _n1Min);
+    _n1 = (_n1 + dt*_decay * n1Target) / (1 + dt*_decay);
+
+    // The actual thrust produced is keyed to the N1 speed.  Add the
+    // afterburners in at the end.
+    float betaN1 =  (_epr0-1) * (_n1 - _n1Min) / (_n1Max - _n1Min);
+    _thrust *= betaN1/(betaTarget+.00001); // blowup protection
+    _thrust *= 1 + _reheat*(_abFactor-1);
+
+    // Finally, calculate the output variables.   Use a 80/20 mix of
+    // the N2/N1 speeds as the key.
+    float beta = 0.8*betaN2 + 0.2*betaN1;
+    _epr = beta + 1;
+    float ff0 = _maxThrust*_tsfc*(1/(3600*9.8)); // takeoff fuel flow, kg/s
+    _fuelFlow = ff0 * beta*ibeta0;
+    _fuelFlow *= 1 + (3.5 * _reheat * _abFactor); // Afterburners take
+						  // 3.5 times as much
+						  // fuel per thrust unit
+    _egt = T0 + beta*ibeta0 * (_egt0 - T0);
+}
+
 void Jet::getThrust(float* out)
 {
-    float t = _thrust * _throttle;
+    Math::mul3(_thrust, _dir, out);
-    t += (_abThrust - _thrust) * _reheat;
+
-    t *= _rho / _rho0;
+    // Rotate about the Y axis for thrust vectoring
-    Math::mul3(t, _dir, out);
+    float angle = _rotControl * _maxRot;
+    float s = Math::sin(angle);
+    float c = Math::cos(angle);
+    float o0 = out[0];
+    out[0] =  c * o0 + s * out[2];
+    out[2] = -s * o0 + c * out[2];
 }
 
 void Jet::getTorque(float* out)
@@ -51,14 +212,4 @@ void Jet::getGyro(float* out)
     return;
 }
 
-float Jet::getFuelFlow()
-{
-    return 0;
-}
-
-void Jet::integrate(float dt)
-{
-    return;
-}
-
 }; // namespace yasim

src/FDM/YASim/Jet.hpp

@@ -5,18 +5,35 @@
 
 namespace yasim {
 
-// Incredibly dumb placeholder for a Jet implementation.  But it does
-// what's important, which is provide thrust.
 class Jet : public Thruster {
 public:
     Jet();
 
     virtual Jet* getJet() { return this; }
+    
+    void setMaxThrust(float thrust, float afterburner=0);
+    void setVMax(float spd);
+    void setTSFC(float tsfc);
+    void setRPMs(float idleN1, float maxN1, float idleN2, float maxN2);
+    void setEGT(float takeoffEGT);
+    void setEPR(float takeoffEPR);
+    void setVectorAngle(float angle);
 
-    void setDryThrust(float thrust);
+    // The time it takes the engine to reach 90% thrust from idle
-    void setReheatThrust(float thrust);
+    void setSpooling(float time);
+
+    // Sets the reheat control
     void setReheat(float reheat);
 
+    // Sets the thrust vector control (0-1)
+    void setRotation(float rot);
+
+    float getN1();
+    float getN2();
+    float getEPR();
+    float getEGT();
+
+    // From Thruster:
     virtual void getThrust(float* out);
     virtual void getTorque(float* out);
     virtual void getGyro(float* out);
@@ -25,10 +42,33 @@ public:
     virtual void stabilize();
 
 private:
-    float _thrust;
-    float _abThrust;
-    float _rho0;
     float _reheat;
+
+    float _maxThrust; // Max dry thrust at sea level
+    float _abFactor;  // Afterburner thrust multiplier
+
+    float _maxRot;
+    float _rotControl;
+
+    float _decay;  // time constant for the exponential integration
+    float _vMax;   // speed at which thrust is zero
+    float _epr0;   // EPR at takeoff thrust
+    float _tsfc;   // TSFC ((lb/hr)/lb) at takeoff thrust and zero airspeed
+    float _egt0;   // EGT at takeoff thrust
+    float _n1Min;  // N1 at ground idle
+    float _n1Max;  // N1 at takeoff thrust
+    float _n2Min;  // N2 at ground idle
+    float _n2Max;  // N2 at takeoff thrust
+
+    float _thrust;   // Current thrust
+    float _epr;      // Current EPR
+    float _n1;       // Current UNCORRECTED N1 (percent)
+    float _n2;       // Current UNCORRECTED N2 (percent)
+    float _fuelFlow; // Current UNCORRECTED fuel flow (kg/s)
+    float _egt;      // Current UNCORRECTED EGT (kelvin)
+
+    float _tempCorrect; // Intake temp / std temp (273 K)
+    float _pressureCorrect; // Intake pressure / std pressure
 };
 
 }; // namespace yasim

src/FDM/YASim/Makefile.am

@@ -4,6 +4,6 @@ libYASim_a_SOURCES = YASim.cxx Airplane.cpp Atmosphere.cpp ControlMap.cpp \
                      FGFDM.cpp Gear.cpp Glue.cpp Integrator.cpp Jet.cpp   \
                      Math.cpp Model.cpp PistonEngine.cpp Propeller.cpp    \
                      PropEngine.cpp RigidBody.cpp Surface.cpp             \
-                     Thruster.cpp Wing.cpp
+                     Thruster.cpp Wing.cpp SimpleJet.cpp
 
 INCLUDES += -I$(top_srcdir) -I$(top_srcdir)/src

src/FDM/YASim/PistonEngine.cpp

@@ -3,11 +3,16 @@
 #include "PistonEngine.hpp"
 namespace yasim {
 
+const static float HP2W = 745.7;
+const static float CIN2CM = 1.6387064e-5;
+
 PistonEngine::PistonEngine(float power, float speed)
 {
+    _boost = 1;
+
     // Presume a BSFC (in lb/hour per HP) of 0.45.  In SI that becomes
-    // (2.2 lb/kg, 745.7 W/hp, 3600 sec/hour) 3.69e-07 kg/Ws.
+    // (2.2 lb/kg, 745.7 W/hp, 3600 sec/hour) 7.62e-08 kg/Ws.
-    _f0 = power * 3.69e-07;
+    _f0 = power * 7.62e-08;
 
     _power0 = power;
     _omega0 = speed;
@@ -23,6 +28,12 @@ PistonEngine::PistonEngine(float power, float speed)
 
     _turbo = 1;
     _maxMP = 1e6; // No waste gate on non-turbo engines.
+
+    // Guess at reasonable values for these guys.  Displacements run
+    // at about 2 cubic inches per horsepower or so, at least for
+    // non-turbocharged engines.
+    _compression = 8;
+    _displacement = power * (2*CIN2CM/HP2W);
 }
 
 void PistonEngine::setTurboParams(float turbo, float maxMP)
@@ -32,13 +43,23 @@ void PistonEngine::setTurboParams(float turbo, float maxMP)
 
     // This changes the "sea level" manifold air density
     float P0 = Atmosphere::getStdPressure(0);
-    float P = P0 * _turbo;
+    float P = P0 * (1 + _boost * (_turbo - 1));
     if(P > _maxMP) P = _maxMP;
     float T = Atmosphere::getStdTemperature(0) * Math::pow(P/P0, 2./7.);
     _rho0 = P / (287.1 * T);
 }
 
-float PistonEngine::getPower()
+void PistonEngine::setDisplacement(float d)
+{
+    _displacement = d;
+}
+
+void PistonEngine::setCompression(float c)
+{
+    _compression = c;
+}
+
+float PistonEngine::getMaxPower()
 {
     return _power0;
 }
@@ -53,22 +74,52 @@ void PistonEngine::setMixture(float m)
     _mixture = m;
 }
 
-void PistonEngine::calc(float P, float T, float speed,
+void PistonEngine::setBoost(float boost)
-			float* torqueOut, float* fuelFlowOut)
 {
-    // The actual fuel flow
+    _boost = boost;
-    float fuel = _mixture * _mixCoeff * speed;
+}
 
-    // manifold air density
+float PistonEngine::getTorque()
-    if(_turbo != 1) {
+{
-        float P1 = P * _turbo;
+    return _torque;
-        if(P1 > _maxMP) P1 = _maxMP;
+}
-        T *= Math::pow(P1/P, 2./7.);
+
-        P = P1;
+float PistonEngine::getFuelFlow()
-    }
+{
-    float density = P / (287.1 * T);
+    return _fuelFlow;
-    
+}
-    float rho = density * _throttle;
+
+float PistonEngine::getMP()
+{
+    return _mp;
+}
+
+float PistonEngine::getEGT()
+{
+    return _egt;
+}
+
+void PistonEngine::calc(float pressure, float temp, float speed)
+{
+    // Calculate manifold pressure as ambient pressure modified for
+    // turbocharging and reduced by the throttle setting.  According
+    // to Dave Luff, minimum throttle at sea level corresponds to 6"
+    // manifold pressure.  Assume that this means that minimum MP is
+    // always 20% of ambient pressure.
+    _mp = pressure * (1 + _boost*(_turbo-1)); // turbocharger
+    _mp *= (0.2 + 0.8 * _throttle);            // throttle
+    if(_mp > _maxMP) _mp = _maxMP;             // wastegate
+
+    // Air entering the manifold does so rapidly, and thus the
+    // pressure change can be assumed to be adiabatic.  Calculate a
+    // temperature change, and use that to get the density.
+    float T = temp * Math::pow(_mp/pressure, 2.0/7.0);
+    float rho = _mp / (287.1 * T);
+
+    // The actual fuel flow is determined only by engine RPM and the
+    // mixture setting.  Not all of this will burn with the same
+    // efficiency.
+    _fuelFlow = _mixture * speed * _mixCoeff;
 
     // How much fuel could be burned with ideal (i.e. uncorrected!)
     // combustion.
@@ -81,18 +132,39 @@ void PistonEngine::calc(float P, float T, float speed,
     // interpolate.  This vaguely matches a curve I copied out of a
     // book for a single engine.  Shrug.
     float burned;
-    float r = fuel/burnable;
+    float r = _fuelFlow/burnable;
     if     (burnable == 0) burned = 0;
-    else if(r < .625)      burned = fuel;
+    else if(r < .625)      burned = _fuelFlow;
     else if(r > 1.375)     burned = burnable;
-    else                   burned = fuel + (burnable-fuel)*(r-.625)*(4.0/3.0);
+    else
+        burned = _fuelFlow + (burnable-_fuelFlow)*(r-.625)*(4.0/3.0);
 
     // And finally the power is just the reference power scaled by the
-    // amount of fuel burned.
+    // amount of fuel burned, and torque is that divided by RPM.
     float power = _power0 * burned/_f0;
+    _torque = power/speed;
 
-    *torqueOut = power/speed;
+    // Now EGT.  This one gets a little goofy.  We can calculate the
-    *fuelFlowOut = fuel;
+    // work done by an isentropically expanding exhaust gas as the
+    // mass of the gas times the specific heat times the change in
+    // temperature.  The mass is just the engine displacement times
+    // the manifold density, plus the mass of the fuel, which we know.
+    // The change in temperature can be calculated adiabatically as a
+    // function of the exhaust gas temperature and the compression
+    // ratio (which we know).  So just rearrange the equation to get
+    // EGT as a function of engine power.  Cool.  I'm using a value of
+    // 1300 J/(kg*K) for the exhaust gas specific heat.  I found this
+    // on a web page somewhere; no idea if it's accurate.  Also,
+    // remember that four stroke engines do one combustion cycle every
+    // TWO revolutions, so the displacement per revolution is half of
+    // what we'd expect.  And diddle the work done by the gas a bit to
+    // account for non-thermodynamic losses like internal friction;
+    // 10% should do it.
+
+    float massFlow = _fuelFlow + (rho * 0.5 * _displacement * speed);
+    float specHeat = 1300;
+    float corr = 1.0/(Math::pow(_compression, 0.4) - 1);
+    _egt = corr * (power * 1.1) / (massFlow * specHeat);
 }
 
 }; // namespace yasim

src/FDM/YASim/PistonEngine.hpp

@@ -8,33 +8,43 @@ public:
     // Initializes an engine from known "takeoff" parameters.
     PistonEngine(float power, float spd);
     void setTurboParams(float mul, float maxMP);
+    void setDisplacement(float d);
+    void setCompression(float c);
 
     void setThrottle(float throttle);
     void setMixture(float mixture);
+    void setBoost(float boost); // fraction of turbo-mul used
 
-    float getPower();
+    float getMaxPower(); // max sea-level power
 
-    // Calculates power output and fuel flow, based on a given
+    void calc(float pressure, float temp, float speed);
-    // throttle setting (0-1 corresponding to the fraction of
+    float getTorque();
-    // "available" manifold pressure), mixture (fuel flux per rpm,
+    float getFuelFlow();
-    // 0-1, where 1 is "max rich", or a little bit more than needed
+    float getMP();
-    // for rated power at sea level)
+    float getEGT();
-    void calc(float pressure, float temp, float speed,
-	      float* powerOut, float* fuelFlowOut);
 
 private:
+    // Static configuration:
     float _power0;   // reference power setting
     float _omega0;   //   "       engine speed
     float _rho0;     //   "       manifold air density
     float _f0;       // "ideal" fuel flow at P0/omega0
     float _mixCoeff; // fuel flow per omega at full mixture
+    float _turbo;    // (or super-)charger pressure multiplier
+    float _maxMP;    // wastegate setting
+    float _displacement; // piston stroke volume
+    float _compression;  // compression ratio (>1)
 
     // Runtime settables:
     float _throttle;
     float _mixture;
+    float _boost;
 
-    float _turbo;
+    // Runtime state/output:
-    float _maxMP;
+    float _mp;
+    float _torque;
+    float _fuelFlow;
+    float _egt;
 };
 
 }; // namespace yasim

src/FDM/YASim/PropEngine.cpp

@@ -79,9 +79,10 @@ void PropEngine::stabilize()
     bool goingUp = false;
     float step = 10;
     while(true) {
-	float etau, ptau, dummy;
+	float ptau, dummy;
 	_prop->calc(_rho, speed, _omega, &dummy, &ptau);
-	_eng->calc(_pressure, _temp, _omega, &etau, &dummy);
+	_eng->calc(_pressure, _temp, _omega);
+        float etau = _eng->getTorque();
 	float tdiff = etau - ptau;
 
 	if(Math::abs(tdiff/_moment) < 0.1)
@@ -110,9 +111,10 @@ void PropEngine::integrate(float dt)
     _eng->setThrottle(_throttle);
     _eng->setMixture(_mixture);
     
-    _prop->calc(_rho, speed, _omega,
+    _prop->calc(_rho, speed, _omega, &thrust, &propTorque);
-		&thrust, &propTorque);
+    _eng->calc(_pressure, _temp, _omega);
-    _eng->calc(_pressure, _temp, _omega, &engTorque, &_fuelFlow);
+    engTorque = _eng->getTorque();
+    _fuelFlow = _eng->getFuelFlow();
 
     // Turn the thrust into a vector and save it
     Math::mul3(thrust, _dir, _thrust);

src/FDM/YASim/SimpleJet.cpp

@@ -0,0 +1,46 @@
+#include "Math.hpp"
+#include "SimpleJet.hpp"
+
+namespace yasim {
+
+SimpleJet::SimpleJet()
+{
+    _thrust = 0;
+}
+
+void SimpleJet::setThrust(float thrust)
+{
+    _thrust = thrust;
+}
+
+void SimpleJet::getThrust(float* out)
+{
+    Math::mul3(_thrust * _throttle, _dir, out);
+}
+
+void SimpleJet::getTorque(float* out)
+{
+    out[0] = out[1] = out[2] = 0;
+}
+
+void SimpleJet::getGyro(float* out)
+{
+    out[0] = out[1] = out[2] = 0;
+}
+
+float SimpleJet::getFuelFlow()
+{
+    return 0;
+}
+
+void SimpleJet::integrate(float dt)
+{
+    return;
+}
+
+void SimpleJet::stabilize()
+{
+    return;
+}
+
+}; // namespace yasim

src/FDM/YASim/SimpleJet.hpp

@@ -0,0 +1,25 @@
+#ifndef _SIMPLEJET_HPP
+#define _SIMPLEJET_HPP
+
+#include "Thruster.hpp"
+
+namespace yasim {
+
+// As simple a Thruster subclass as you can find. It makes thrust.  Period.
+class SimpleJet : public Thruster
+{
+public:
+    SimpleJet();
+    void setThrust(float thrust);
+    virtual void getThrust(float* out);
+    virtual void getTorque(float* out);
+    virtual void getGyro(float* out);
+    virtual float getFuelFlow();
+    virtual void integrate(float dt);
+    virtual void stabilize();
+private:
+    float _thrust;
+};
+
+}; // namespace yasim
+#endif // _SIMPLEJET_HPP

src/FDM/YASim/YASim.cxx

@@ -39,9 +39,12 @@ void YASim::printDEBUG()
     if(debugCount >= 3) {
 	debugCount = 0;
 
-// 	printf("RPM %.1f FF %.1f\n",
+//  	printf("N1 %5.1f N2 %5.1f FF %7.1f EPR %4.2f EGT %6.1f\n",
-// 	       fgGetFloat("/engines/engine[0]/rpm"),
+//  	       fgGetFloat("/engines/engine[0]/n1"),
-// 	       fgGetFloat("/engines/engine[0]/fuel-flow-gph"));
+//  	       fgGetFloat("/engines/engine[0]/n2"),
+//  	       fgGetFloat("/engines/engine[0]/fuel-flow-gph"),
+//  	       fgGetFloat("/engines/engine[0]/epr"),
+//  	       fgGetFloat("/engines/engine[0]/egt"));
 
 // 	printf("gear: %f\n", fgGetFloat("/controls/gear-down"));
 
@@ -59,14 +62,9 @@ YASim::YASim(double dt)
     set_delta_t(dt);
     _fdm = new FGFDM();
 
-    // Because the integration method is via fourth-order Runge-Kutta,
+    _dt = dt;
-    // we only get an "output" state for every 4 times the internal
+
-    // forces are calculated.  So divide dt by four to account for
-    // this, and only run an iteration every fourth time through
-    // update.
-    _dt = dt * 4;
     _fdm->getAirplane()->getModel()->getIntegrator()->setInterval(_dt);
-    _updateCount = 0;
 }
 
 void YASim::report()
@@ -97,6 +95,25 @@ void YASim::report()
     }
 }
 
+void YASim::bind()
+{
+    // Run the superclass bind to set up a bunch of property ties
+    FGInterface::bind();
+
+    // Now UNtie the ones that we are going to set ourselves.
+    fgUntie("/consumables/fuel/tank[0]/level-gal_us");
+    fgUntie("/consumables/fuel/tank[1]/level-gal_us");
+
+    char buf[256];
+    for(int i=0; i<_fdm->getAirplane()->getModel()->numThrusters(); i++) {
+	sprintf(buf, "/engines/engine[%d]/fuel-flow-gph", i); fgUntie(buf);
+	sprintf(buf, "/engines/engine[%d]/rpm", i);           fgUntie(buf);
+	sprintf(buf, "/engines/engine[%d]/mp-osi", i);        fgUntie(buf);
+	sprintf(buf, "/engines/engine[%d]/egt-degf", i);      fgUntie(buf);
+    }
+
+}
+
 void YASim::init()
 {
     Airplane* a = _fdm->getAirplane();
@@ -141,7 +158,9 @@ void YASim::init()
 	sprintf(buf, "/controls/propeller-pitch[%d]", i); fgSetFloat(buf, 1);
 	sprintf(buf, "/controls/afterburner[%d]", i);     fgSetFloat(buf, 0);
     }
-    
+
+    fgSetFloat("/controls/slats", 0);
+    fgSetFloat("/controls/spoilers", 0);
 
     // Are we at ground level?  If so, lift the plane up so the gear
     // clear the ground
@@ -167,8 +186,11 @@ void YASim::init()
     // Blank the state, and copy in ours
     State s;
     m->setState(&s);
-
     copyToYASim(true);
+
+    _fdm->getExternalInput();
+    _fdm->getAirplane()->stabilizeThrust();
+
     set_inited(true);
 }
 
@@ -180,18 +202,11 @@ void YASim::update(int iterations)
 
     int i;
     for(i=0; i<iterations; i++) {
-        // Remember, update only every 4th call
-        _updateCount++;
-        if(_updateCount >= 4) {
-
 	    copyToYASim(false);
 	    _fdm->iterate(_dt);
 	    copyFromYASim();
 
 	    printDEBUG();
-
-            _updateCount = 0;
-        }
     }
 }
 
@@ -420,7 +435,7 @@ void YASim::copyFromYASim()
 
             pe->getTorque(tmp);
             float power = Math::mag3(tmp) * pe->getOmega();
-            float maxPower = pe->getPistonEngine()->getPower();
+            float maxPower = pe->getPistonEngine()->getMaxPower();
 
             fge->set_MaxHP(maxPower * W2HP);
             fge->set_Percentage_Power(100 * power/maxPower);

src/FDM/YASim/YASim.hxx

@@ -11,6 +11,7 @@ public:
 
     // Load externally set stuff into the FDM
     virtual void init();
+    virtual void bind();
 
     // Run an iteration
     virtual void update(int iterations);
@@ -23,7 +24,6 @@ public:
     void printDEBUG();
 
     yasim::FGFDM* _fdm;
-    int _updateCount;
     float _dt;
 };