JSBSim JSBSim is an ongoing attempt at producing an OO Flight Dynamics Model (FDM) to replace LaRCsim as the default FDM for FlightGear. It can also be used standalone. JSBSim uses config files to represent aircraft, engines, propellers, etc. Also, the flight control system is described in the config file. Normally, for use with FlightGear, the config files are named this way [case is significant]: <FG_ROOT>/Aircraft/<aircraft name>/<aircraft name>.xml Engines are named like this: <FG_ROOT>/Engines/<engine name>.xml Aircraft and engine config files are present in the FGFS Base package which must be downloaded. See the FlightGear web site for more information. How to run FGFS using JSBSim All the various FDMs are currently compiled into FGFS. You can specify which FDM you want at run time. You can also specify which aircraft you want. Currently, for JSBSim only the X-15 and C-172 aircraft are available. Here is an example command line used to start up FlightGear using JSBSim as the FDM: fgfs --fdm=jsb --aircraft=X15 --units-feet --altitude=60000 --uBody=2000 --wBody=120 or, fgfs --fdm=jsb --aircraft=c172 [Note: uBody is the forward velocity of the aircraft, wBody is the downward velocity - from the aircraft point of view. This essentially means that the aircraft is going forward fast and has an angle of attack of about 4 degrees or so] The first command line sets up the initial velocity and altitude to allow the X15 to glide down. Note that if you fire up the engine, it will burn for only about two minutes and then run out of fuel - but you will go very, very fast! The second command line example will start up the C172 on the end of the runway. Check out the JSBSim home page at http://jsbsim.sf.net. Please report any bugs to email@example.com, or firstname.lastname@example.org, or post on the jsbsim web site using the SourceForge bug tracking system for the project. JSBSim is written by Jon S. Berndt and Tony Peden with contributions by other FlightGear programmers, as well.