Move the calculations of Mach to the base class.

diff --git a/src/AIModel/AIBallistic.cxx b/src/AIModel/AIBallistic.cxx
index 5bfadf48b403cd9a11166d968b74740795c1060f..2a9f97e733993674164850c7e873cdb60c6ed249 100644 (file)
--- a/src/AIModel/AIBallistic.cxx
+++ b/src/AIModel/AIBallistic.cxx
@@ -36,7 +36,6 @@ FGAIBallistic::FGAIBallistic(FGAIManager* mgr) {
     gravity = 32;
 //  buoyancy = 64;
     no_roll = false;
-    Mach = 0.4;
 }
 
 FGAIBallistic::~FGAIBallistic() {

diff --git a/src/AIModel/AIBallistic.hxx b/src/AIModel/AIBallistic.hxx
index 83231bcf3e8b4300649bbdff1552964750f336b5..82309ea2b8bbb1ec62c613917c4f4cbbe6a720b9 100644 (file)
--- a/src/AIModel/AIBallistic.hxx
+++ b/src/AIModel/AIBallistic.hxx
@@ -67,7 +67,6 @@ private:
     bool wind;              // if true, local wind will be applied to object
     double Cd;              // drag coefficient
     double mass;            // slugs
-    double Mach;
 
     void Run(double dt);
 };

diff --git a/src/AIModel/AIBase.cxx b/src/AIModel/AIBase.cxx
index 935d5c660ac9ee3c0d310f70b69e435da6d53b9e..db566a1ef19bd17a71ddea692dd06f6dc53ff25c 100644 (file)
--- a/src/AIModel/AIBase.cxx
+++ b/src/AIModel/AIBase.cxx
@@ -98,9 +98,23 @@ void FGAIBase::update(double dt) {
     }
 
     rho = p / (1718 * (T + 459.7));
+       
+       // calculate the speed of sound at altitude
+       // a = sqrt ( g * R * (T + 459.7))
+       // where:
+       // a = speed of sound [ft/s]
+       // g = specific heat ratio, which is usually equal to 1.4  
+       // R = specific gas constant, which equals 1716 ft-lb/slug/°R 
+       
+       a = sqrt ( 1.4 * 1716 * (T + 459.7));
+       
+       // calculate Mach number
+       
+       Mach = speed/a;
+       
+//     cout  << "Speed(ft/s) "<< speed <<" Altitude(ft) "<< altitude << " Mach " << Mach;
 }
 
-
 void FGAIBase::Transform() {
     if (!invisible) {
       aip.setPosition(pos.lon(), pos.lat(), pos.elev() * SG_METER_TO_FEET);

diff --git a/src/AIModel/AIBase.hxx b/src/AIModel/AIBase.hxx
index f8728561d0b446d0582a0e5e472c938084656ccf..5cc92b5b4e8dff6358d85b8219d48b1f4b5d8c32 100644 (file)
--- a/src/AIModel/AIBase.hxx
+++ b/src/AIModel/AIBase.hxx
@@ -182,6 +182,9 @@ public:
     double rho;
     double T;                             // temperature, degs farenheit
     double p;                             // pressure lbs/sq ft
+       double a;                             // speed of sound at altitude (ft/s)
+       double Mach;                          // Mach number
+       
     static const double e;
     static const double lbs_to_slugs;