Set the format default to float instead of int.

[flightgear.git] / src / AIModel / AIBase.cxx

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);