b9e4775a7a
- finish cleanup/optimization of instrumentation system (started by mfranz) - improve configuration of special properties by addressing them directly
76 lines
1.8 KiB
C++
76 lines
1.8 KiB
C++
// pitot.cxx - the pitot air system.
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// Written by David Megginson, started 2002.
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//
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// This file is in the Public Domain and comes with no warranty.
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#include <simgear/constants.h>
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#include <Main/fg_props.hxx>
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#include <Main/util.hxx>
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#include "pitot.hxx"
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PitotSystem::PitotSystem ( SGPropertyNode *node )
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:
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_name(node->getStringValue("name", "pitot")),
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_num(node->getIntValue("number", 0))
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{
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}
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PitotSystem::~PitotSystem ()
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{
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}
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void
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PitotSystem::init ()
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{
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string branch;
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branch = "/systems/" + _name;
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SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
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_serviceable_node = node->getChild("serviceable", 0, true);
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_pressure_node = fgGetNode("/environment/pressure-inhg", true);
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_density_node = fgGetNode("/environment/density-slugft3", true);
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_velocity_node = fgGetNode("/velocities/airspeed-kt", true);
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_slip_angle = fgGetNode("/orientation/side-slip-rad", true);
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_total_pressure_node = node->getChild("total-pressure-inhg", 0, true);
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}
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void
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PitotSystem::bind ()
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{
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}
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void
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PitotSystem::unbind ()
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{
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}
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#ifndef INHGTOPSF
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# define INHGTOPSF (2116.217/29.9212)
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#endif
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#ifndef PSFTOINHG
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# define PSFTOINHG (1/INHGTOPSF)
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#endif
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void
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PitotSystem::update (double dt)
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{
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if (_serviceable_node->getBoolValue()) {
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// The pitot tube sees the forward
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// velocity in the body axis.
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double p = _pressure_node->getDoubleValue() * INHGTOPSF;
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double r = _density_node->getDoubleValue();
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double v = _velocity_node->getDoubleValue() * SG_KT_TO_FPS;
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v *= cos(_slip_angle->getDoubleValue());
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if (v < 0.0)
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v = 0.0;
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double q = 0.5 * r * v * v; // dynamic
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_total_pressure_node->setDoubleValue((p + q) * PSFTOINHG);
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}
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}
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// end of pitot.cxx
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