Aircraft systems

Almost all aircraft needs systems of different kinds. Eg. fuel electric, vacuum, hydraulic.

By default an aircraft is supplied with generic systems defined in generic-systems.xml. The workings of these systems are hard-coded in c++. See the source code.

Flightgear also has standard implementations of different common aircraft instruments and avionics. These creates useful output properties, found under instrumentation in the property tree, that can be used either by directly adding the generic instruments available in Aircraft/Instruments-3d or as input to your own instruments. Many of these standard instrument implementations are dependent on system properties to work. A list of dependencies are found here.

Electric

The standard electric system implementation is considered deprecated but are still used in many aircrafts. A xml configuration file is used. The generic electrical system configuration is based on that of a small single engine aircraft. For information on configuration see README.electrical provided in the Doc folder. As an alternative you can build a Nasal based system.

Here are two engines for Nasal-based electric systems:

Buckaroo's: A Nasal-Based Electrical System for Flightgear

AndersM's: Howto:A system engine in Nasal

Fuel

For JSBSim based aircrafts you can make fuel systems integrated in the FDM. See Howto:Write a fuel system in JSBSim.

Hydraulic

No standard hydraulic system is available. For JSBSim based aircrafts you can make hydraulic systems integrated in the FDM.

Pitot

A simple system with two output properties, total-pressure-inhg and measured-total-pressure-inhg.

Static

A simple system with one output property, pressure-inhg.

Vacuum

Vacuum has one output propery: suction-inhg. This property is used to drive gyros needed in the standard instrument implementation. The generic implementation is based on a piston-engine and the vacuum depends on the engine's rpm:

    <rpm>/engines/engine[1]/rpm</rpm>
    <scale>1.0</scale>

You can set another property as source for the vacuum. If rpm times factor is greater than approx. 500 you will have fully functional gyros at all (resonable) altitudes. Eg using an electric output to drive the gyro vacuum:

    <rpm>systems/electrical/outputs/inst_ac</rpm>
    <scale>50.0</scale>