JSBSim Flight Dynamics Model / News: Recent posts

The Thruster definition in the JSBSim config file format has been moved into the Engine definition. This provides a firmer link between a thruster (representing a propeller, nozzle, etc.) with its "parent" engine.

JSBSim now features planetary rotation
effects on flight path -- more commonly known as coriolis and centrifugal accelerations. This is most noticeable in FGPropagation - see the EOM in Run().
I think the equations are fairly easy to follow (as easy as the EOM can be, anyhow).
This enables us to do single-stage-to-orbit kinds of things, etc.

In order to communicate the growth and development of JSBSim (the OO-Open Source Flight Dynamics Model in C++) to a wider audience outside of the normal developer constituency, a quarterly newsletter has been launched. This will also allow for a printed analogue to the JSBSim web site to exist - you can take the news with you and share it with others.

The first issue covers some basic information about JSBSim, as well as some exciting news about upcoming events. You can read the inaugural issue of "Back of the Envelope" here:... read more

The "Links" page has been fleshed out considerably, with roughly 100 new links to technical papers dealing with simulation issues, and subjects discussing items of interest for aircraft modelers. Go to www.jsbsim.org, and select the "Links" link at left.

JSBSim developer David Culp found a new atmosphere model described here:

http://www.nrl.navy.mil/content.php?P=03REVIEW105

We have located the code and are experimenting with importing the model into JSBSim.

JSBSim (actually, a slightly modified version of it) is mentioned as having been used in the dissertation, "Robust Non-linear Control through Neuroevolution", by Faustino John Gomez:

http://www.cs.utexas.edu/ftp/pub/AI-Lab/tech-reports/UT-AI-TR-03-303.pdf

JSBSim is mentioned in an article about FlightGear by Howard Wen on the O'Reilly network:

http://linux.oreillynet.com/pub/a/linux/2003/12/11/flightgear.html

The JSBSim aircraft configuration files can be a little confusing for beginners - especially for those who are not terribly familiar with aircraft dynamics and control. In an effort at easing the process of creating an aircraft flight model to use with JSBSim and FlightGear (www.flightgear.org), David Culp has created a clever web application called Aeromatic. With a few quick clicks of the mouse, a usable boilerplate model can be created. For maximum accuracy, the file can be further edited after examination, and as more refined data is acquired. The code for Aeromatic is managed as part of the JSBSim project (www.jsbsim.org). To try it out, go to the JSBSim home page and select the Aeromatic link in the left panel.

I have added a new document to the JSBSim web site that deals with automatic flight and flight controls using JSBSim. It is a work in progress (aren't they all?). Please send any comments/criticisms/praise to jon@jsbsim.org

FlightGear (featuring JSBSim, YASim, and UIUC-LarcSim) is comparitively reviewed against MSFS and X-Plane (say that fast and it sounds like "explain") in the April 2003 issue of EAA's magazine, "Sport Aviation". JSBSim is mentioned explicitly a couple of times. The article was quite positive.

JSBSim 0.9.4 has been released in the form of a source gzipped tarball. It includes the new FCS switch and deadband components. See the release notes. It also includes a capability where a takeoff report is generated similar to the landing report.

The Deadband control has been "fleshed out" and is now functional. Complete testing is pending.

JSBSim now supports configurable switches in the flight control system. This allows switches - either panel on/off or conditional rotary switches - to be defined in the configuration file. The definition uses properties to define the conditions.

Tony has added a new feature to JSBSim, the ability to create variables (via the property tree) in the config file. These variables can be created and assigned values in the FCS (flight control system) then referenced anywhere else in the config file (such as in a coefficient). Every flight control system is unique, and we wanted to avoid having hard coded support for every permutation. The property tree gives us the opportunity to support almost any configuration without hard-coding.

A new page has been added to the JSBSim web site highlighting users. Go to http://jsbsim.sf.net/users.html

The JSBSim Cessna 310 model has been improved in code and in the model. No longer does the aircraft crash upon achieving a negative alpha.

JSBSim 0.9.1 sources have been tarred up and placed in the download section for those who don't want or can't use CVS.

David Megginson has finished the initial C-310 twin config file and JSBSim has implemented the requisite code changes/bug fixes. Reportedly it flies nicely.

Recently, David Luff's piston engine model was added to JSBSim, thanks to David Megginson's efforts.

David Megginson: "With this change, the various displays (such as EGT and MP) are live, as they are with LaRCSim, and you can lean the engine to get better performance; with only a little extra work, we can add support for magnetos, realistic startup sequence, and oil temperature (and get JSBSim to use the model's fuel-flow calculations).

JSBSim, a configurable flight dynamics model (FDM), has quietly been selected as the new default flight dynamics model for the open source, multi-platform FlightGear flight simulator. JSBSim replaces the NASA Langley "LaRCSim" FDM as the FlightGear default. However, any one of several FDMs including LaRCSim or JSBSim can be easily selected at runtime when running FlightGear. JSBSim continues to undergo rapid development, particularly in the area of aerodynamic modeling.

JSBSim v0.8.2 has been integrated into FlightGear. Recently, some fixes have been made to the engine/propeller model, the XLR99 rocket engine model for the X-15, as well as other changes. For standalone operation more scripting features have been added which essentially allows for a crude autopilot to be constructed for testing, validation, and debugging uses.

The latest version of JSBSim (0.8.2) has been integrated with FlightGear. There are still some issues to resolve, but it is an improvement over the previous version.

A JSBSim binary release for Linux has been placed in the Files section. This is identical to the release placed on the site for the Windows platform yesterday (3/19/2001).

JSBSim is in the process of moving to SourceForge from its current site.