Make sure that all elapsed time gets passed to update when a subsystem

[flightgear.git] / src / Systems / pitot.cxx

diff --git a/src/Systems/pitot.cxx b/src/Systems/pitot.cxx
index 0a58805b53ca1ecd649044add09dc33d6e9268b0..daa20edec50d2fffd542c12d5a24f13cd630cffb 100644 (file)
--- a/src/Systems/pitot.cxx
+++ b/src/Systems/pitot.cxx
@@ -22,7 +22,7 @@ PitotSystem::init ()
     _serviceable_node = fgGetNode("/systems/pitot[0]/serviceable", true);
     _pressure_node = fgGetNode("/environment/pressure-inhg", true);
     _density_node = fgGetNode("/environment/density-slugft3", true);
-    _velocity_node = fgGetNode("/velocities/uBody-fps", true);
+    _velocity_node = fgGetNode("/velocities/airspeed-kt", true);
     _total_pressure_node =
         fgGetNode("/systems/pitot[0]/total-pressure-inhg", true);
 }
@@ -37,16 +37,25 @@ PitotSystem::unbind ()
 {
 }
 
+#ifndef INHGTOPSF
+# define INHGTOPSF (2116.217/29.9212)
+#endif
+
+#ifndef KTTOFPS
+# define KTTOFPS 1.68781
+#endif
+
+
 void
 PitotSystem::update (double dt)
 {
     if (_serviceable_node->getBoolValue()) {
                                 // The pitot tube sees the forward
                                 // velocity in the body axis.
-        double p = _pressure_node->getDoubleValue();
+        double p = _pressure_node->getDoubleValue(); // static
         double r = _density_node->getDoubleValue();
-        double v = _velocity_node->getDoubleValue();
-        double q = 0.5 * r * v * v; // dynamic pressure
+        double v = _velocity_node->getDoubleValue() * KTTOFPS;
+        double q = 0.5 * r * v * v / INHGTOPSF; // dynamic
         _total_pressure_node->setDoubleValue(p + q);
     }
 }