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fgdata/Aircraft/Generic/limits.nas
ehofman 7f11bb92db Stuart Buchanan:
- Provide generic Nasal code to check if a pilot is abusing their aircraft
  by extending their gear/flaps above the maximum allowed speed, exceeding
  Vne, or pulling excessive G-forces.
- Implement limits within the C182.
2006-01-06 09:47:58 +00:00

150 lines
4.5 KiB
Text

# $Id$
#
# Nasal script to print errors to the screen when aircraft exceed design limits:
# - extending flaps above maximum flap extension speed
# - extending gear above maximum gear extension speed
# - exceeding Vna
# - exceeding structural G limits
#
#
# to use, define one or more of
# limits/max-flap-extension-speed
# limits/vne
# limits/max-gear-extension-speed
# limits/max-positive-g
# limits/max-negative-g (must be defined in max-positive-g defined)
#
# then include this .nas file in the aircraft XML. Note that .nas file must be
# included _after_ limits have been defined.
#
# ==================================== timer stuff ===========================================
# set the update period
UPDATE_PERIOD = 0.3;
# set the timer for the selected function
registerTimer = func {
settimer(arg[0], UPDATE_PERIOD);
} # end function
# =============================== end timer stuff ===========================================
# =============================== Pilot G stuff (taken from hurricane.nas) =================================
pilot_g = props.globals.getNode("fdm/jsbsim/accelerations/a-pilot-z-ft_sec2", 1);
timeratio = props.globals.getNode("accelerations/timeratio", 1);
pilot_g_damped = props.globals.getNode("fdm/jsbsim/accelerations/damped-a-pilot-z-ft_sec2", 1);
pilot_g.setDoubleValue(0);
pilot_g_damped.setDoubleValue(0);
timeratio.setDoubleValue(0.03);
g_damp = 0;
updatePilotG = func {
var n = timeratio.getValue();
var g = pilot_g.getValue() ;
#if (g == nil) { g = 0; }
g_damp = ( g * n) + (g_damp * (1 - n));
pilot_g_damped.setDoubleValue(g_damp);
settimer(updatePilotG, 0.1);
} #end updatePilotG()
updatePilotG();
# ======================= Load/Speed limits =========================
if ((getprop("limits/max-flap-extension-speed") != nil) or
(getprop("limits/vne") != nil) or
(getprop("limits/max-gear-extension-speed") != nil) or
(getprop("limits/max-positive-g") != nil))
{
setprop("/accelerations/pilot/z-accel-fps_sec",0);
checkLimits = func {
# Flaps extension speed check
if (getprop("limits/max-flap-extension-speed") != nil)
{
if ((getprop("surface-positions/flap-pos-norm") > 0) and
(getprop("velocities/airspeed-kt") > getprop("limits/max-flap-extension-speed")) and
(getprop("limits/flap-warning-displayed") != 1))
{
# display a warning once
screenPrint("Flaps extended above maximum flap extension speed!");
setprop("limits/flap-warning-displayed", 1);
}
if ((getprop("surface-positions/flap-pos-norm") == 0) or
(getprop("velocities/airspeed-kt") < getprop("limits/max-flap-extension-speed")))
{
#reset warning message
setprop("limits/flap-warning-displayed", 0);
}
}
# G-loads check - both limits must be defined
if (getprop("limits/max-positive-g") != nil)
{
# Convert the ft/sec^2 into Gs - allowing for gravity.
g = (- getprop("/fdm/jsbsim/accelerations/damped-a-pilot-z-ft_sec2")) / 32;
setprop("limits/current-g", g);
if (g < getprop("limits/max-negative-g"))
{
screenPrint("Airframe structural negative-g load limit exceeded!");
}
if (g > getprop("limits/max-positive-g"))
{
screenPrint("Airframe structural positive-g load limit exceeded!");
}
}
# Vne speed check
if (getprop("limits/vne") != nil)
{
# Simply check we haven't exceeded the maximum speed for the aircraft
if (getprop("velocities/airspeed-kt") > getprop("limits/vne"))
{
screenPrint("Airspeed exceeds Vne!");
}
}
# Gear extension speed check. We check whether the gear is being extended or retracted.
if (getprop("limits/max-gear-extension-speed") != nil)
{
if ((getprop("gear/gear[0]/position-norm") != getprop("/controls/gear/gear-down")) and
(getprop("velocities/airspeed-kt") > getprop("limits/max-gear-extension-speed")) and
(getprop("limits/gear-warning-displayed") != 1))
{
# display a warning once
screenPrint("Gear extended above maximum gear extension speed!");
setprop("limits/gear-warning-displayed", 1);
}
if ((getprop("gear/gear[0]/position-norm") == getprop("/controls/gear/gear-down")) or
(getprop("velocities/airspeed-kt") < getprop("limits/max-gear-extension-speed")))
{
#reset warning message
setprop("limits/gear-warning-displayed", 0);
}
}
registerTimer(checkLimits);
}
}
checkLimits();