// A higher number means more responsive.
#define RESPONSIVENESS 50.0
-
-AirspeedIndicator::AirspeedIndicator ()
+AirspeedIndicator::AirspeedIndicator ( SGPropertyNode *node )
+ :
+ _name(node->getStringValue("name", "airspeed-indicator")),
+ _num(node->getIntValue("number", 0)),
+ _total_pressure(node->getStringValue("total-pressure", "/systems/pitot/total-pressure-inhg")),
+ _static_pressure(node->getStringValue("static-pressure", "/systems/static/pressure-inhg")),
+ _has_overspeed(node->getBoolValue("has-overspeed-indicator",false)),
+ _pressure_alt_source(node->getStringValue("pressure-alt-source", "/instrumentation/altimeter/pressure-alt-ft")),
+ _ias_limit(node->getDoubleValue("ias-limit", 248.0)),
+ _mach_limit(node->getDoubleValue("mach-limit", 0.48)),
+ _alt_threshold(node->getDoubleValue("alt-threshold", 13200))
{
}
void
AirspeedIndicator::init ()
{
- _serviceable_node =
- fgGetNode("/instrumentation/airspeed-indicator/serviceable",
- true);
- _total_pressure_node =
- fgGetNode("/systems/pitot/total-pressure-inhg", true);
- _static_pressure_node =
- fgGetNode("/systems/static/pressure-inhg", true);
- _speed_node =
- fgGetNode("/instrumentation/airspeed-indicator/indicated-speed-kt",
- true);
+ string branch;
+ branch = "/instrumentation/" + _name;
+
+ SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
+ _serviceable_node = node->getChild("serviceable", 0, true);
+ _total_pressure_node = fgGetNode(_total_pressure.c_str(), true);
+ _static_pressure_node = fgGetNode(_static_pressure.c_str(), true);
+ _density_node = fgGetNode("/environment/density-slugft3", true);
+ _speed_node = node->getChild("indicated-speed-kt", 0, true);
+
+ // overspeed-indicator properties
+ if (_has_overspeed) {
+ _ias_limit_node = node->getNode("ias-limit",0, true);
+ _mach_limit_node = node->getNode("mach-limit",0, true);
+ _alt_threshold_node = node->getNode("alt-threshold",0, true);
+
+ if (!_ias_limit_node->hasValue()) {
+ _ias_limit_node->setDoubleValue(_ias_limit);
+ }
+
+ if (!_mach_limit_node->hasValue()) {
+ _mach_limit_node->setDoubleValue(_mach_limit);
+ }
+
+ if (!_alt_threshold_node->hasValue()) {
+ _alt_threshold_node->setDoubleValue(_alt_threshold);
+ }
+
+ _airspeed_limit = node->getChild("airspeed-limit-kt", 0, true);
+ _pressure_alt = fgGetNode(_pressure_alt_source.c_str(), true);
+ _mach = fgGetNode("/velocities/mach", true);
+ }
}
-#ifndef SEA_LEVEL_DENSITY_SLUGFG3
-# define SEA_LEVEL_DENSITY_SLUGFT3 0.002378
-#endif
-
#ifndef FPSTOKTS
# define FPSTOKTS 0.592484
#endif
void
AirspeedIndicator::update (double dt)
{
- if (_serviceable_node->getBoolValue()) {
- double pt = _total_pressure_node->getDoubleValue();
- double p = _static_pressure_node->getDoubleValue();
- double q = ( pt - p ) * INHGTOPSF; // dynamic pressure
-
- // Now, reverse the equation (normalize dynamic pressure to
- // avoid "nan" results from sqrt)
- if ( q < 0 ) { q = 0.0; }
- double v_fps = sqrt((2 * q) / SEA_LEVEL_DENSITY_SLUGFT3);
-
- // Publish the indicated airspeed
- double last_speed_kt = _speed_node->getDoubleValue();
- double current_speed_kt = v_fps * FPSTOKTS;
- _speed_node->setDoubleValue(fgGetLowPass(last_speed_kt,
- current_speed_kt,
- dt * RESPONSIVENESS));
+ if (!_serviceable_node->getBoolValue()) {
+ return;
+ }
+
+ double pt = _total_pressure_node->getDoubleValue() * INHGTOPSF;
+ double p = _static_pressure_node->getDoubleValue() * INHGTOPSF;
+ double r = _density_node->getDoubleValue();
+ double q = ( pt - p ); // dynamic pressure
+
+ // Now, reverse the equation (normalize dynamic pressure to
+ // avoid "nan" results from sqrt)
+ if ( q < 0 ) { q = 0.0; }
+ double v_fps = sqrt((2 * q) / r);
+
+ // Publish the indicated airspeed
+ double last_speed_kt = _speed_node->getDoubleValue();
+ double current_speed_kt = v_fps * FPSTOKTS;
+ double filtered_speed = fgGetLowPass(last_speed_kt,
+ current_speed_kt,
+ dt * RESPONSIVENESS);
+ _speed_node->setDoubleValue(filtered_speed);
+
+ if (!_has_overspeed) {
+ return;
+ }
+
+ double lmt = _ias_limit_node->getDoubleValue();
+ if (_pressure_alt->getDoubleValue() > _alt_threshold_node->getDoubleValue()) {
+ double mmo = _mach_limit_node->getDoubleValue();
+ lmt = (filtered_speed/_mach->getDoubleValue())* mmo;
}
+
+ _airspeed_limit->setDoubleValue(lmt);
}
// end of airspeed_indicator.cxx