From 5a9c5d80c89f738ba1f94de765905b35f0d61409 Mon Sep 17 00:00:00 2001
From: andy <andy>
Date: Fri, 30 Jan 2004 23:21:26 +0000
Subject: [PATCH] Thrust reversers.  Very simple implementation.

---
 src/FDM/YASim/ControlMap.cpp | 7 ++++---
 src/FDM/YASim/ControlMap.hpp | 3 ++-
 src/FDM/YASim/FGFDM.cpp      | 2 ++
 src/FDM/YASim/Jet.cpp        | 4 ++++
 src/FDM/YASim/Jet.hpp        | 8 ++++++++
 5 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/FDM/YASim/ControlMap.cpp b/src/FDM/YASim/ControlMap.cpp
index fd4f99b7c..9854cac28 100644
--- a/src/FDM/YASim/ControlMap.cpp
+++ b/src/FDM/YASim/ControlMap.cpp
@@ -200,10 +200,11 @@ void ControlMap::applyControls(float dt)
 	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 COLLECTIVE:   ((Rotor*)obj)->setCollective(lval);        break;
-        case CYCLICAIL:    ((Rotor*)obj)->setCyclicail(lval,rval);         break;
-        case CYCLICELE:    ((Rotor*)obj)->setCyclicele(lval,rval);         break;
+        case COLLECTIVE:   ((Rotor*)obj)->setCollective(lval);     break;
+        case CYCLICAIL:    ((Rotor*)obj)->setCyclicail(lval,rval); break;
+        case CYCLICELE:    ((Rotor*)obj)->setCyclicele(lval,rval); break;
         case ROTORENGINEON: ((Rotor*)obj)->setEngineOn((int)lval); break;
+	case REVERSE_THRUST: ((Jet*)obj)->setReverse(lval != 0);   break;
 	case BOOST:
 	    ((Thruster*)obj)->getPistonEngine()->setBoost(lval);
 	    break;
diff --git a/src/FDM/YASim/ControlMap.hpp b/src/FDM/YASim/ControlMap.hpp
index c3dbda2ee..07d15f301 100644
--- a/src/FDM/YASim/ControlMap.hpp
+++ b/src/FDM/YASim/ControlMap.hpp
@@ -14,7 +14,8 @@ public:
 		      BRAKE, STEER, EXTEND,
 		      INCIDENCE, FLAP0, FLAP1, SLAT, SPOILER, VECTOR,
                       BOOST, CASTERING, PROPPITCH, 
-                      COLLECTIVE, CYCLICAIL, CYCLICELE, ROTORENGINEON};
+                      COLLECTIVE, CYCLICAIL, CYCLICELE, ROTORENGINEON,
+                      REVERSE_THRUST };
 
     enum { OPT_SPLIT  = 0x01,
            OPT_INVERT = 0x02,
diff --git a/src/FDM/YASim/FGFDM.cpp b/src/FDM/YASim/FGFDM.cpp
index ed0bd1504..7f3077fce 100644
--- a/src/FDM/YASim/FGFDM.cpp
+++ b/src/FDM/YASim/FGFDM.cpp
@@ -159,6 +159,7 @@ void FGFDM::startElement(const char* name, const XMLAttributes &atts)
 	j->setMaxThrust(attrf(a, "thrust") * LBS2N,
 			attrf(a, "afterburner", 0) * LBS2N);
 	j->setVectorAngle(attrf(a, "rotate", 0) * DEG2RAD);
+        j->setReverseThrust(attrf(a, "reverse", 0.2));
 
  	float n1min = attrf(a, "n1-idle", 55);
 	float n1max = attrf(a, "n1-max", 102);
@@ -680,6 +681,7 @@ int FGFDM::parseOutput(const char* name)
     if(eq(name, "CYCLICAIL")) return ControlMap::CYCLICAIL;
     if(eq(name, "CYCLICELE")) return ControlMap::CYCLICELE;
     if(eq(name, "ROTORENGINEON")) return ControlMap::ROTORENGINEON;
+    if(eq(name, "REVERSE_THRUST")) return ControlMap::REVERSE_THRUST;
     SG_LOG(SG_FLIGHT,SG_ALERT,"Unrecognized control type '"
            << name << "' in YASim aircraft description.");
     exit(1);
diff --git a/src/FDM/YASim/Jet.cpp b/src/FDM/YASim/Jet.cpp
index edd364bee..afbb669cd 100644
--- a/src/FDM/YASim/Jet.cpp
+++ b/src/FDM/YASim/Jet.cpp
@@ -10,6 +10,7 @@ Jet::Jet()
     _reheat = 0;
     _rotControl = 0;
     _maxRot = 0;
+    _reverseThrust = false;
 
     // Initialize parameters for an early-ish subsonic turbojet.  More
     // recent turbofans will typically have a lower vMax, epr0, and
@@ -193,6 +194,9 @@ void Jet::integrate(float dt)
 						  // 3.5 times as much
 						  // fuel per thrust unit
     _egt = T0 + beta*ibeta0 * (_egt0 - T0);
+
+    // Thrust reverse handling:
+    if(_reverseThrust) _thrust *= -_reverseEff;
 }
 
 bool Jet::isRunning()
diff --git a/src/FDM/YASim/Jet.hpp b/src/FDM/YASim/Jet.hpp
index b5d5f92f5..2376aa950 100644
--- a/src/FDM/YASim/Jet.hpp
+++ b/src/FDM/YASim/Jet.hpp
@@ -28,6 +28,12 @@ public:
     // Sets the thrust vector control (0-1)
     void setRotation(float rot);
 
+    // Thrust reverser control.
+    void setReverse(bool reverse) { _reverseThrust = reverse; }
+
+    // Thrust reverser effectiveness.
+    void setReverseThrust(float eff) { _reverseEff = eff; }
+
     float getN1();
     float getN2();
     float getEPR();
@@ -45,6 +51,7 @@ public:
 
 private:
     float _reheat;
+    bool _reverseThrust;
 
     float _maxThrust; // Max dry thrust at sea level
     float _abFactor;  // Afterburner thrust multiplier
@@ -61,6 +68,7 @@ private:
     float _n1Max;  // N1 at takeoff thrust
     float _n2Min;  // N2 at ground idle
     float _n2Max;  // N2 at takeoff thrust
+    float _reverseEff; // Thrust reverser effectiveness (fraction)
 
     bool _running;   // Is the engine running?
     bool _cranking;  // Is the engine cranking?
-- 
2.39.5