40 lines
1.5 KiB
Text
40 lines
1.5 KiB
Text
# SPDX-License-Identifier: GPL-2.0-or-later
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#
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# NOTE! This copyright does *not* cover user models that use these Nasal
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# services by normal function calls - this is merely considered normal use
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# of the code, and does *not* fall under the heading of "derived work."
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#
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# Copyright (C) 2010 by Vivian Meazza
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# Copyright (C) 2013 by Philosopher
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# Copyright (C) 2020 by Henning Stahlke
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#########
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# contrail calculator. Based on an approxmation to the "Appleman Chart"
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# y = -0.077x2 + 2.7188x - 64.36
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########
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var pressure_Node = props.globals.initNode("environment/pressure-inhg", 1, "DOUBLE");
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var temperature_Node = props.globals.initNode("environment/temperature-degc", 1, "DOUBLE");
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var contrail_Node = props.globals.initNode("environment/contrail", 1, "BOOL");
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var contrail_temp_Node = props.globals.initNode("environment/contrail-temperature-degc", 1, "DOUBLE");
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var static_contrail_node = props.globals.getNode("sim/ai/aircraft/contrail", 1);
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var time_node = props.globals.getNode("sim/time/elapsed-sec", 1);
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updateContrail = func {
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var x = pressure_Node.getValue();
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var y = temperature_Node.getValue();
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var con_temp = -0.077 * x * x + 2.7188 * x - 64.36;
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contrail_temp_Node.setValue(con_temp);
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if (y < con_temp and y < -40) {
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contrail_Node.setValue(1);
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} else {
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contrail_Node.setValue(0);
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}
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}
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updateContrail(); # avoid 30 second delay on startup https://sourceforge.net/p/flightgear/codetickets/2077/
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contrailTimer = maketimer(30, updateContrail);
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contrailTimer.simulatedTime = 1;
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contrailTimer.restart(30);
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