Howto:Add instruments to a cockpit

Work in progress This article or section will be worked on in the upcoming hours or days. See history for the latest developments.

Many of the aircraft offerred for download on the FlightGear aircraft download page are detailled and complete. Some models, however lack instrumentation, and in many cases only basic instruments are available. Fortunately, adding new instruments is a relatively easy task. The biggest difficulty is actually placing the instrument accurately, not to get it working.

For aircraft that are licensed under the GNU GPL (all aircraft on the official download page are), instruments can be re-used in other aircraft when released under the same license.

Adding instruments to existing models

Adding instruments consists of a few major steps:

1. Locate an FG aircraft with a similar instrument.
2. Copy XML tags relevant to the instrument files into XML file of the aircraft you want to update.
3. Edit the updated aircraft file to place the instrument.

An example

Let's update the instruments of the Dash 8-300Q for a start.

The existing aircraft, version v20101217 from the version 2.6 aircraft download page has the following set of basic flight instruments.

• Air Speed Indicator (ASI)
• Altimeter
• Artificial Horizon

Cockpit of the Dash 8 with some instruments missing.

We can see that our aircraft is lacking the following:

• Vertical Speed Indicator (VSI)
• Electronic Flight Systems Information (EFSI)
• Electronic Horizontal Situation Indicator (EHSI)
• Radio Magnetic Indicator (RMI)
• VOR instrument

First let's add the VSI (Vertical Speed Indicator) . Locate the tags for the ASI in a similar aircraft config file, the Beech 1900D (B1900D). These appear in the B1900D.xml file as follows:

<model>

       <name>VSI 1 gauge</name>
       <path>Aircraft/b1900d/Models/Instruments/vsi.xml</path>
       <offsets>
           <x-m>-4.860</x-m>
           <y-m>-0.280</y-m>
           <z-m>-0.082</z-m>
           <pitch-deg>-10</pitch-deg>
       </offsets>
   </model>

Copy this set of tags as shown above into the Dash8 300Q xml file containing the instruments in the models folder. The file is named dhc8-300Q.xml

The instrument now has to be placed in position. This is done by changing the x, y and z coordinates as listed above.

We will use an existing instrument, the Air Speed Indicator of the DHC8 as a reference. The DHC 8 pilot ASI has the following settings.

  <model>
    	<name>Pilot asi</name>
   <path>Aircraft/dhc8/Models/Instruments/asi300-3d.xml</path>
       <offsets>
           <x-m>-8.927</x-m>
           <y-m>-0.702</y-m>
           <z-m>2.382</z-m>
           <pitch-deg>0</pitch-deg>
       </offsets>
   </model>

Copy the <offsets> ... </offsets> section and paste it into the offsets section of the VSI instrument, replacing the existing settings.

<model>

       <name>VSI 1 gauge</name>
       <path>Aircraft/b1900d/Models/Instruments/vsi.xml</path>
       <offsets>
           <x-m>-8.927</x-m>
           <y-m>-0.702</y-m>
           <z-m>2.382</z-m>
           <pitch-deg>0</pitch-deg>
       </offsets>
   </model>

You will find that the VSI, the new instrument, will appear on top of the existing one. This confirms that the instrument appears in the cockpit.

To place the instrument in a correct location, use the following adjustments:

           <x-m>-8.927</x-m>  distance of the instrument from the pilot (depth)
           <y-m>-0.702</y-m>  sideways location of the instrument
           <z-m>2.382</z-m>   vertical location of the instrument

Using the offsets for an existing instrument, the altimeter, ALT, the VSI can be placed directly on top of the ALT using the offsets for the Altimeter, which is <y-m>-0.44</y-m>. To move the VSI down, experiment with different values of the z value, 2.182, 2.282, 2.382 etc.

Finally, adjust the depth of the instrument (x - value)

A shortcut: multiple copies of an instrument

FlightGear allows the creation of the same instrument copies in different locations in the cockpit. We can use this to our advantage: placing copies of the same instrument in different locations in the cockpit and selecting the right one.

VSI in multiple locations. Choose the best.

More on placement

• X: specifies the depth, and in this case is a negative value. The increase in the value, say from -2.330 to -2.430 means the instrument will move away from you into the panel, towards the nose of the aircraft.
• Y: is the simplest, here, and simply specifies left/right values. The pilot ASI is listed with an Y value of -xxx. The value of zero means it is centre in the panel. You will notice the the co-pilot's ASI has a positive value of xxx.
• Z: gives the position of the instrument in the vertical direction. For example 2.223 will place the instrument higher than 2.123 in the panel.

Instrument path

The path can be left as follows, or the instrument xml files and image files can be copied to the DHC8 folder and the reference can be changed to that folder:

<path>Aircraft/b1900d/Models/Instruments/vsi.xml</path>

can be changed to

<path>Aircraft/dhc8/Models/Instruments/vsi.xml</path>

Several instruments added. Fine adjustment needed.

External link

• Flight instruments (Wikipedia)