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only consider positive airspeed in longitudinal axis

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mfranz 2006-07-17 18:14:31 +00:00
parent a4265a3b0a
commit 98cd4a9086
2 changed files with 9 additions and 7 deletions
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14
src/Systems/pitot.cxx
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@ -3,10 +3,12 @@
// //
// This file is in the Public Domain and comes with no warranty. // This file is in the Public Domain and comes with no warranty.
#include "pitot.hxx" #include <simgear/constants.h>
#include <Main/fg_props.hxx> #include <Main/fg_props.hxx>
#include <Main/util.hxx> #include <Main/util.hxx>
#include "pitot.hxx"
PitotSystem::PitotSystem ( SGPropertyNode *node ) PitotSystem::PitotSystem ( SGPropertyNode *node )
@ -53,6 +55,7 @@ PitotSystem::init ()
_pressure_node = fgGetNode("/environment/pressure-inhg", true); _pressure_node = fgGetNode("/environment/pressure-inhg", true);
_density_node = fgGetNode("/environment/density-slugft3", true); _density_node = fgGetNode("/environment/density-slugft3", true);
_velocity_node = fgGetNode("/velocities/airspeed-kt", true); _velocity_node = fgGetNode("/velocities/airspeed-kt", true);
_slip_angle = fgGetNode("/orientation/side-slip-rad", true);
_total_pressure_node = node->getChild("total-pressure-inhg", 0, true); _total_pressure_node = node->getChild("total-pressure-inhg", 0, true);
} }
@ -74,10 +77,6 @@ PitotSystem::unbind ()
# define PSFTOINHG (1/INHGTOPSF) # define PSFTOINHG (1/INHGTOPSF)
#endif #endif
#ifndef KTTOFPS
# define KTTOFPS 1.68781
#endif
void void
PitotSystem::update (double dt) PitotSystem::update (double dt)
@ -87,7 +86,10 @@ PitotSystem::update (double dt)
// velocity in the body axis. // velocity in the body axis.
double p = _pressure_node->getDoubleValue() * INHGTOPSF; double p = _pressure_node->getDoubleValue() * INHGTOPSF;
double r = _density_node->getDoubleValue(); double r = _density_node->getDoubleValue();
double v = _velocity_node->getDoubleValue() * KTTOFPS; 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 double q = 0.5 * r * v * v; // dynamic
_total_pressure_node->setDoubleValue((p + q) * PSFTOINHG); _total_pressure_node->setDoubleValue((p + q) * PSFTOINHG);
} }

2
src/Systems/pitot.hxx
View file

@ -59,8 +59,8 @@ private:
SGPropertyNode_ptr _pressure_node; SGPropertyNode_ptr _pressure_node;
SGPropertyNode_ptr _density_node; SGPropertyNode_ptr _density_node;
SGPropertyNode_ptr _velocity_node; SGPropertyNode_ptr _velocity_node;
SGPropertyNode_ptr _slip_angle;
SGPropertyNode_ptr _total_pressure_node; SGPropertyNode_ptr _total_pressure_node;
}; };
#endif // __SYSTEMS_PITOT_HXX #endif // __SYSTEMS_PITOT_HXX