//
// This file is in the Public Domain and comes with no warranty.
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
#include "vacuum.hxx"
+
+#include <cstring>
+
#include <Main/fg_props.hxx>
-VacuumSystem::VacuumSystem( int i )
+VacuumSystem::VacuumSystem ( SGPropertyNode *node )
+ :
+ _name(node->getStringValue("name", "vacuum")),
+ _num(node->getIntValue("number", 0)),
+ _scale(node->getDoubleValue("scale", 1.0))
{
- num = i;
+ for ( int i = 0; i < node->nChildren(); ++i ) {
+ SGPropertyNode *child = node->getChild(i);
+ if (!strcmp(child->getName(), "rpm"))
+ _rpms.push_back(child->getStringValue());
+ }
}
VacuumSystem::~VacuumSystem ()
void
VacuumSystem::init()
{
- // TODO: allow index of engine to be
- // configured.
- SGPropertyNode *node = fgGetNode("/systems/vacuum", num, true );
+ unsigned int i;
+ string branch;
+ branch = "/systems/" + _name;
+
+ SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
_serviceable_node = node->getChild("serviceable", 0, true);
- _rpm_node = fgGetNode("/engines/engine[0]/rpm", true);
+ for ( i = 0; i < _rpms.size(); i++ ) {
+ SGPropertyNode_ptr _rpm_node = fgGetNode(_rpms[i].c_str(), true);
+ _rpm_nodes.push_back( _rpm_node );
+ }
_pressure_node = fgGetNode("/environment/pressure-inhg", true);
_suction_node = node->getChild("suction-inhg", 0, true);
}
// Model taken from steam.cxx
double suction;
+ unsigned int i;
if (!_serviceable_node->getBoolValue()) {
suction = 0.0;
} else {
- double rpm = _rpm_node->getDoubleValue();
+ // select the source with the max rpm
+ double rpm = 0.0;
+ for ( i = 0; i < _rpm_nodes.size(); i++ ) {
+ double tmp = _rpm_nodes[i]->getDoubleValue() * _scale;
+ if ( tmp > rpm ) {
+ rpm = tmp;
+ }
+ }
double pressure = _pressure_node->getDoubleValue();
- // suction = pressure * rpm / (rpm + 5000.0);
- // This magic formula yields about 4.1 inhg at 700 rpm and
- // about 6.0 inhg at 2200 rpm (numbers by observation)
- suction = 5.39 - 1.0 / ( rpm * 0.00111 );
+ // This magic formula yields about 4 inhg at 700 rpm
+ suction = pressure * rpm / (rpm + 4875.0);
+
+ // simple regulator model that clamps smoothly to about 5 inhg
+ // over a normal rpm range
+ double max = (rpm > 0 ? 5.39 - 1.0 / ( rpm * 0.00111 ) : 0);
if ( suction < 0.0 ) suction = 0.0;
- if ( suction > 5.0 ) suction = 5.0;
+ if ( suction > max ) suction = max;
}
_suction_node->setDoubleValue(suction);
}