httpd: don't spam the console with debug messages

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

diff --git a/src/Systems/pitot.cxx b/src/Systems/pitot.cxx
index 535caa09db89e5af9d2e40e0e9ccb7af8659f27f..cf3eb2590a03af3ac93ce0125af390f58c71ae4b 100644 (file)
--- a/src/Systems/pitot.cxx
+++ b/src/Systems/pitot.cxx
@@ -1,8 +1,13 @@
 // pitot.cxx - the pitot air system.
 // Written by David Megginson, started 2002.
 //
+// Last modified by Eric van den Berg, 01 Nov 2013
 // This file is in the Public Domain and comes with no warranty.
 
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
 #include <simgear/constants.h>
 
 #include <Main/fg_props.hxx>
@@ -14,7 +19,9 @@
 PitotSystem::PitotSystem ( SGPropertyNode *node )
     :
     _name(node->getStringValue("name", "pitot")),
-    _num(node->getIntValue("number", 0))
+    _num(node->getIntValue("number", 0)),
+    _stall_factor(cos(node->getDoubleValue("stall-deg", 60.0) * SGD_DEGREES_TO_RADIANS ))
+                       // this is the projection factor for the stall angle.
 {
 }
 
@@ -31,10 +38,14 @@ PitotSystem::init ()
     SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
     _serviceable_node = node->getChild("serviceable", 0, true);
     _pressure_node = fgGetNode("/environment/pressure-inhg", true);
-    _density_node = fgGetNode("/environment/density-slugft3", true);
-    _velocity_node = fgGetNode("/velocities/airspeed-kt", true);
-    _slip_angle = fgGetNode("/orientation/side-slip-rad", true);
+    _mach_node = fgGetNode("/velocities/mach", true);
+    _alpha_deg_node = fgGetNode("/orientation/alpha-deg", true);
+    _beta_deg_node = fgGetNode("/orientation/side-slip-deg", true);
     _total_pressure_node = node->getChild("total-pressure-inhg", 0, true);
+    _measured_total_pressure_node = node->getChild("measured-total-pressure-inhg", 0, true);
+    if ( _stall_factor < 0 ) { // |stall angle| > 90°
+               _stall_factor = cos(60 * SGD_DEGREES_TO_RADIANS);
+       }
 }
 
 void
@@ -47,29 +58,30 @@ PitotSystem::unbind ()
 {
 }
 
-#ifndef INHGTOPSF
-# define INHGTOPSF (2116.217/29.9212)
-#endif
-
-#ifndef PSFTOINHG
-# define PSFTOINHG (1/INHGTOPSF)
-#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() * INHGTOPSF;
-        double r = _density_node->getDoubleValue();
-        double v = _velocity_node->getDoubleValue() * SG_KT_TO_FPS;
-        v *= cos(_slip_angle->getDoubleValue());
-        if (v < 0.0)
-            v = 0.0;
-        double q = 0.5 * r * v * v; // dynamic
-        _total_pressure_node->setDoubleValue((p + q) * PSFTOINHG);
+        double p = _pressure_node->getDoubleValue();
+        double mach = _mach_node->getDoubleValue();
+        double alpha = _alpha_deg_node->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
+        double beta = _beta_deg_node->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
+           double x_proj_factor = cos(alpha) * fabs(cos(beta));  // the factor to project the total speed vector on the longitudinal body axis
+
+        double p_t = p;                                                                                // pitot tube stalled: total pressure = static pressure
+        double p_t_meas = p;
+
+        if ( x_proj_factor > _stall_factor ) {                         // NOTE: alpha: -180 - 180, beta: -90 - 90, pitot probe is stalled at more than 60 deg
+            p_t = p * pow(1 + 0.2 * mach*mach*x_proj_factor*x_proj_factor, 3.5 );              // total pressure in the pitot tube if not stalled
+            p_t_meas = p_t;
+
+            if (mach > 1) {
+                p_t_meas = p * pow( 1.2 * mach*mach, 3.5 ) * pow( 2.8/2.4*mach*mach - 0.4 / 2.4 , -2.5 );    // measured total pressure by pitot tube (Rayleigh formula, at Mach>1, normal shockwave in front of pitot tube)
+            }
+        }
+
+        _total_pressure_node->setDoubleValue(p_t);
+        _measured_total_pressure_node->setDoubleValue(p_t_meas);
     }
 }