1JSBSim 2 3JSBSim is an ongoing attempt at producing an OO Flight Dynamics Model 4(FDM) to replace LaRCsim as the default FDM for FlightGear. It can 5also be used standalone. 6 7JSBSim uses config files to represent aircraft, engines, propellers, 8etc. Also, the flight control system is described in the config 9file. Normally, for use with FlightGear, the config files are named 10this way [case is significant]: 11 12<FG_ROOT>/Aircraft/<aircraft name>/<aircraft name>.xml 13 14Engines are named like this: 15 16<FG_ROOT>/Engines/<engine name>.xml 17 18Aircraft and engine config files are present in the FGFS Base package 19which must be downloaded. See the FlightGear web site for more 20information. 21 22How to run FGFS using JSBSim 23 24All the various FDMs are currently compiled into FGFS. You can specify 25which FDM you want at run time. You can also specify which aircraft 26you want. Currently, for JSBSim only the X-15 and C-172 aircraft are 27available. Here is an example command line used to start up FlightGear 28using JSBSim as the FDM: 29 30fgfs --fdm=jsb --aircraft=X15 --units-feet --altitude=60000 --uBody=2000 --wBody=120 31 32or, 33 34fgfs --fdm=jsb --aircraft=c172 35 36[Note: uBody is the forward velocity of the aircraft, wBody is the 37downward velocity - from the aircraft point of view. This essentially 38means that the aircraft is going forward fast and has an angle of 39attack of about 4 degrees or so] 40 41The first command line sets up the initial velocity and altitude to 42allow the X15 to glide down. Note that if you fire up the engine, it 43will burn for only about two minutes and then run out of fuel - but 44you will go very, very fast! The second command line example will 45start up the C172 on the end of the runway. 46 47Check out the JSBSim home page at http://jsbsim.sf.net. Please report 48any bugs to jsb@hal-pc.org, or apeden@earthlink.net, or post on the 49jsbsim web site using the SourceForge bug tracking system for the 50project. 51 52JSBSim is written by Jon S. Berndt and Tony Peden with contributions 53by other FlightGear programmers, as well. 54