Default head-up display
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The Head-up display (HUD) is an important instrument in modern, mostly military, cockpits. FlightGear provides a XML-based system to relatively easily create HUDs for aircrafts such as the F-14 and F-16.
However, this article's focus is on FlightGear's default head-up displays. Those are available for any craft which does not include its own set. Have a look at #Further Information if you're planning to create a HUD.
Activate the HUD with the [h]-key. Pressing it repeatedly moves through the configured colours and turns it off again. To change the brightness, press [shift]+[h]. Press [shift]+[i] to go through the available HUD's. Press [i] to switch back to the first one at any time. Have in mind that some aircraft do assign one or more of those keys differently and therefore one or more function/s is/are missing on them.
Some of the head-up display's options can be altered in the menu: View --> Adjust HUD Properties
- Monitors the bearing of the control input on the aileron's axis. Attached along the upper side is the indicator for the trim input on that axis.
- Monitors the bearing of the control input on the elevator's axis. Attached to the left the trim on this axis.
- Monitors the bearing of the control input on the rudder's axis. Attached to the bottom the trim input.
- Monitors the throttle input axis.
- AMSL (Height above mean sea level)
- Current altitude relative to sea level in feet (ft) (1 ft = 30.48 cm).
- The g-force appealing to the pilot - to avoid black-/redout.
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- This is an ideal version of a gyrocompass without the drawbacks of a real one. It shows heading of the aircraft relative to the geographical North Pole (true north) in degree (360 degree scale).
- KIAS (Knots Indicated Airspeed)
- Current speed relating to the ambient air in knot/knots (kt/kts) (1 kt = 1.151 mph = 1.852 km/h).
- Latitude / Longitude
- Current location according to the geographic coordinate system.
- To change the format of the displayed coordinates, go to Autopilot --> Set Lat/Lon-format.
- Pitch ladder
- Displays the aircraft's pitch and roll relative to the ground's level/horizontal in degree. It's used as an artificial horizon (Attitude indicator).
- Radio altimeter
- Shows current altitude above ground level (AGL) in feet. Relating to the location of the aircraft's radio altimeter, it's not zero if the aircraft is on the ground.
- Turn Coordinator
The setup of the default HUD is defined at $FG_ROOT/Huds/default.xml.
Documentation can be found at $FG_ROOT/Docs/README.hud.
HUD's may be replaced or added by changing or adding their path(s) to preferences.xml (<hud> tag) or by setting the paths as command line options. To change the order of the existing ones the options would be:
- Designed to fly helicopters in Helicopter View it is also handy for any craft with a not yet finished cockpit. It also contains a minimalistic HUD only showing some navigation informations such as compass and GPS. The download contains instructions and specs.