FlightGear Forum
In the past few weeks/months I've developed a simple system to move gliders while they are on the ground. As they have no engines (obviously) gliders have to be carried around with external force, be it people or cars pulling them. This is also the base for my system. It consists of two major parts:
1. assisting gears: These are extra "gears" simulating a person standing next to your glider and holding its wings levelled. It is enabled when the menu entry is selected while the aircraft is on ground and not faster than 15kts (have you ever seen a person running faster than that?
)2. movement system: This also consists of another two parts:
2.1 turn system: These are forces added to the wingtips of the gliders for turning it right/left. It's connected to /controls/flight/rudder when the conditions (same as for asssting gears) are met
2.2 motion system: These are forces added similar to a pushback on the main wheel simulating pushing it back or forward. It's connected to the throttle and reversed by Del-key when the conditions mentioned are met.
The code
Here's the code to add it to any yasim glider you want:
FDM file
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<!--Added for easy ground handling-->
<!--Assiting gears for ground movement-->
<gear x="-2" y="3" z="-0.25" compression=".1" <!-- x/y coordinates: somewhere under your wing, about 3-5m from root--> <!--z coordinate: some centimeters above main wheel contact point-->
spring="0.8" damp="1.2" sfric="0.8" dfric="0.7" skid="true">
<control-input axis="/controls/gear/assist" control="EXTEND"/>
<control-output control="EXTEND" prop="/gear/gear[6]/position-norm"/>
</gear>
<gear x="-2" y="-3" z="-0.25" compression=".1" <!-- x/y coordinates: somewhere under your wing, about 3-5m from root--> <!--z coordinate: some centimeters above main wheel contact point-->
spring="0.8" damp="1.2" sfric="0.8" dfric="0.7" skid="true">
<control-input axis="/controls/gear/assist" control="EXTEND"/>
<control-output control="EXTEND" prop="/gear/gear[7]/position-norm"/>
</gear>
<!--Pushing/pulling the aircraft around:-->
<!--TURN, this is done by tearing the wings around-->
<thruster x="-2.615" y="8" z="0.1" vx="1" vy="-1" vz="0" thrust="100"> <!-- x/y/z coordinates: wingtip-->
<control-input axis="/controls/flight/rudder2" control="THROTTLE" src0="-1" src1="1" dst0="-1" dst1="1"/>
</thruster>
<thruster x="-2.615" y="-8" z="0.1" vx="-1" vy="1" vz="0" thrust="100"> <!-- x/y/z coordinates: wingtip-->
<control-input axis="/controls/flight/rudder2" control="THROTTLE" src0="-1" src1="1" dst0="-1" dst1="1"/>
</thruster>
<!--Push/pull forward-->
<thruster x="-2.615" y="0" z="-0.466" vx="1" vy="0" vz="0" thrust="200"> <!-- x/y/z coordinates: Main wheel contact point-->
<control-input axis="/controls/throttle-2" control="THROTTLE"/>
</thruster>
<!--Push/pull backward-->
<thruster x="-2.615" y="0" z="-0.466" vx="-1" vy="0" vz="0" thrust="200"> <!-- x/y/z coordinates: Main wheel contact point-->
<control-input axis="/controls/throttle-reverse" control="THROTTLE"/>
</thruster>
The nasal file
Put the following into a nasal file called ground-handling.nas (inside YOURAIRCRAFT/Nasal/)
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####ASK13 Ground handling system
setlistener("/sim/signals/fdm-initialized", func {
print("Ground handling system loaded");
settimer(update_systems, 2);
});
var update_systems = func {
#Assisting person
if(getprop("/velocities/groundspeed-kt")<15 & getprop("gear/gear[1]/wow")==1 & getprop("/controls/gear/assist-1")==1){
setprop("controls/gear/assist", 1);
}else{
setprop("controls/gear/assist", 0);
}
#Rudder
#Conditions: must be on ground, must have ground handling enabled (have people standing there) and people can only run up to 15kts (about)
if(getprop("/controls/ground-handling")==1 & getprop("/gear/gear[1]/wow")==1 & getprop("/velocities/groundspeed-kt")<15){
setprop("/controls/flight/rudder2", getprop("/controls/flight/rudder"));
setprop("/controls/flight/aileron2", getprop("/controls/flight/aileron"));
setprop("/controls/throttle-2", getprop("/controls/engines/engine/throttle"));
if(getprop("/controls/engines/engine/reverser")==1){
setprop("/controls/throttle-2", 0);
setprop("/controls/throttle-reverse", getprop("/controls/engines/engine/throttle"));
}else{
setprop("/controls/throttle-reverse", 0);
}
}else{
setprop("/controls/flight/aileron2", 0);
setprop("/controls/flight/rudder2", 0);
setprop("/controls/throttle-2", 0);
setprop("/controls/throttle-reverse", 0);
}
settimer(update_systems,0);
}
The -set.xml
Put these snippets into your -set.xml
1. Nasal file include: Add this into the <nasal> section under the <nameofyouraircraft>
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<file>Aircraft/ASK13/Nasal/systems.nas</file>
2. Keyboard binding - reverse: Add this into <input> <keyboard>:
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<key n="127">
<name>Delete</name>
<desc>Toggle Reversers</desc>
<binding>
<condition>
<less-than>
<property>controls/engines/engine[0]/throttle</property>
<value>0.1</value>
</less-than>
</condition>
<command>property-toggle</command>
<property>controls/engines/engine[0]/reverser</property>
</binding>
</key>
3. Property intialization: Add this into <controls>
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<ground-handling type="bool">false</ground-handling>
4. Menu bindings: Add this into your menu section <sim> <menubar> <default> <menu n="10">
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<item>
<label>Toggle ground handling</label>
<binding>
<command>property-toggle</command>
<property>/controls/ground-handling</property>
</binding>
</item>
<item>
<label>Toggle assiting gears</label>
<binding>
<command>property-toggle</command>
<property>/controls/gear/assist-1</property>
</binding>
</item>
5. Help (optional): Add this into <sim> <help> <text>
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=== Ground handling ===
This aircraft has some features to make ground handling easier/possible at all. When pressing "Toggle assiting gears" the aircraft gets levelled around the x-axes as if someone was holding your wing ;) When pressing "Toggle ground handling", two features are enanled to pull the aircraft around on the ground: 1. All rudder inputs are copied to a thruster, as if someone was pulling your wing so the aircraft turns and 2. all throttle inputs cause your aircraft to taxi, as if someone (or a car) was pulling/pushing it.
When there is somebody with a followme around, you can connect to it by pressing Ctrl+o (release: Ctrl+shift+o) so he can carry you around the airport or even tow you into the air! (also check the Aerotow Settings therefor).
Example:
You can take my ASK13 improved version as an example: https://github.com/D-ECHO/ASK13
What's left to say
Regards and happy gliding!
D-ECHO
