Howto:Adding gun effects
There is no default key/button binding for a trigger in FlightGear, so you will have to make your own. An obvious choice of button would be the trigger on a joystick, but you can also make a keyboard binding by adding something like this to your $FG_ROOT/keyboard.xml file:
<key n="101"> <name>e</name> <desc>Gun Trigger</desc> <binding> <command>property-assign</command> <property>controls/armament/trigger</property> <value>true</value> </binding> <mod-up> <binding> <command>property-assign</command> <property>controls/armament/trigger</property> <value>false</value> </binding> </mod-up> </key>
In the code, we have used e as the trigger. You can change it to a choice of your own but e is the standard key binding used by most aircraft in FlightGear. Joystick bindings are a bit more complex, but are explained in the wiki article on Joysticks.
Adding guns and bullet effects to your Airplane
Once you have a key or button binding defined to active the trigger, you'll then need to add the needed AI_Systems#Submodels configuration file to your airplane's root directory, and ensure the file is activated in your *-set.xml file. The choice of tracer, smoke and impact visual models is up to you. You may also add a sound effect to your sound configuration file that activates with the trigger.
Aircraft already equipped with guns
Some aircraft have the needed submodel files included. All aircraft equipped with guns in Dave's hangar are capable bullet effects. Like:
- Embraer AT-29, A-29B Super Tucano
- McDonnell F-4D/E/F, FGR.2, Phantom II
- Republic F-105D Thunderchief
- North American F-100 Super Sabre
- North American FJ-3 Fury
- LTV A-7E Corsair II
- Dassault Mirage IIIC, F-103E
- MiG-21MF (Fortele Aeriene Române)
Other aircrafts (not from Dave's Hangar) include
- F-16 Fighting Falcon
- Sopwith Camel
- Spad VII
- A6M Zero - Armed version available here : 
- F-15C - Armed version available above----⤴
- Submodel information is not sent with the multiplayer protocol, so multiplayer users will not be effected by your bullets. The tracers, smoke and impact effects will only be seen by you.
- The impact cylinder for models is fairly large, so you will see impacts occur outside of the target model's boundaries.