JSBSim releases

[bcoconni]

JSBSim Latest Release: 1.3.0

• Download binary files
• Python packages are available on PyPI and can be installed with pip
• Conda packages are available via conda-forge. To install with conda, run: conda install -c conda-forge jsbsim

Release 1.3.0

JSBSim version 1.3.0 is a feature release.
Release Date: April 9, 2026
Minimum Python Version: 3.10

Changelog

Major Feature: User Driven Logging Control

Version 1.3.0 introduces a major capability: JSBSim log output can now be redirected and handled directly from Python or C++ by passing a custom logger object with set_logger (Python) or SetLogger (C++).

In practical terms, this means your application can capture and route JSBSim messages to your own logging stack (structured logs, notebooks, GUI consoles, telemetry pipelines, CI diagnostics, etc.) instead of relying on default console output. This is the key functional expansion that justified the minor-version bump to 1.3.0.

Under the hood, JSBSim emits log records through the FGLogger lifecycle. You only need to implement the behavior you care about in a class inherited from FGLogger and register it with set_logger or SetLogger. For full API details, refer to the Python documentation of FGLogger or the C++ documentation of FGLogger.

Python example:

import jsbsim


class AppLogger(jsbsim.FGLogger):
    def __init__(self):
        self._parts = []

    def set_level(self, level: jsbsim.LogLevel) -> None:
        self.log_level = level
        self._parts.clear()

    def message(self, message: str) -> None:
        self._parts.append(message)

    def flush(self) -> None:
        text = "".join(self._parts).rstrip()
        if text:
            print(f"[JSBSim:{self.log_level.name}] {text}")
        self._parts.clear()


jsbsim.set_logger(AppLogger())

User

• New: Added ECEF velocity properties velocities/ecef-x-fps, velocities/ecef-y-fps, and velocities/ecef-z-fps (PR Add properties for ECEF velocities #1398).
• Improvement: Steady-turn trim rate computation now uses true airspeed consistently, improving trim behavior and code clarity in FGTrim rate updates (PR Clean-up variable initialization and calculate psidot using true air … #1404).
• Fix: The global debug_lvl value is no longer reset to 1 when the JSBSIM_DEBUG environment variable is not set, preserving user-selected logging behavior (PR Don't reset debug_lvl if environment variable isn't set #1421).

Unreal Engine Plugin

• Fix: Unreal Engine plugin flight orientation is now corrected for the Flat Planet mode in the GeoReferencing system, fixing reversed flight behavior (PR Unreal Plugin: Fix Flat Planet Bug #1383).

Python Module

• Improvement: Generated Python stub files now include docstrings, so IDEs can display inline API documentation from types (PR Copy the doc strings to the stub file .pyi [skip ci] #1393 and PR Some more fixes for the Python module type hinting. #1415).

Examples

• New: Added a Python notebook example showing JSBSim integration with PathSim for time-domain system simulation workflows (PR Added a Python example demonstrating the use of JSBSim with PathSim - time-domain system simulation framework #1389).

MATLAB S-Function

• Improvement: MATLAB interface logging is now routed through native MATLAB output APIs (mexPrintf and Simulink error/warning reporting), so messages appear in MATLAB/Simulink instead of terminal stdout/stderr (PR Use native Matlab functions to display log messages. #1409).

Developer

• Improvement: Upgraded bundled libexpat from 2.7.0 to 2.7.4, incorporating upstream bug and security fixes (PR Upgrade libexpat to 2.7.4 #1388).
• Fix: Stabilized TestInputSocket.py by replacing fragile newline splitting with splitlines(), preventing intermittent failures caused by platform-dependent line endings and extra blank lines (PR Fix the failure of TestInputSocket.py when extra lines are found. #1392).
• Fix: Removed a false-positive floating-point exception path caused by an uninitialized GeographicLib intermediate variable (s12x) in heading computations (PR Fix FPEs triggerred by uninitialized variable s12x #1399).
• Improvement: Python wheel builds now use scikit-build-core (CMake-native backend), replacing setuptools to simplify build logic and improve cross-platform maintainability (PR Replace setuptools by scikit-build-core to build wheels. #1400).
• Test: Added regression coverage for the debug_lvl behavior and Python logger lifecycle around the JSBSIM_DEBUG handling fix (PR Add a regression test for the debug_lvl bug. #1422).

[bcoconni]

Release 1.1.0

Release Date: Oct 17, 2020
JSBSim version 1.1.0 is the first stable official release from the JSBSim project.

[bcoconni]

Release 1.1.1

JSBSim version 1.1.1 is a bug fix release
Release Date: Oct 24, 2020

Changelog

• Fixed an issue with the <magnetometer> which started after 1000 iterations (issue Magnetometer Startup Sequence Causes ~5 Seconds of Erroneous Data #332).
• An installer is used to release Windows executables and aircraft data.

[bcoconni]

Release 1.1.2

JSBSim version 1.1.2 is a maintenance release.
Release Date: Nov 21, 2020

Changelog

• Fixed assertion failures when the ground callback instance does not set the ellipse parameters of the 'contact' location.
• Now issuing a warning when the clipping max is lower than the min (previously an exception was thrown).
• The socket code is now compatible with OpenBSD
• The minimum inertia allowed for propellers has been lowered from 1e-3 to 1e-6 (see issue Propeller, engine improvements to support quadcopters etc. #333)
• Packages are now provided for Python 3.9 under Windows and MacOSX

[bcoconni]

Release 1.1.3

JSBSim version 1.1.3 is a maintenance release.
Release Date: Jan 22, 2021

Changelog

User

• In <magnetometer>, the Earth magnetic field is now updated every 1000 steps starting at first step.
• The vehicle angular rates are now taken into account in the propellers local velocities (issue Propeller, engine improvements to support quadcopters etc. #333)
• The torque produced by the engines is now correctly accounted for in the vehicle rotational accelerations (issue Propeller, engine improvements to support quadcopters etc. #333)
• Elevator deflection in the example aircraft no longer produces negative drag (issue Negative drag due to elevator deflection #357)
• Fixed an assertion failure which could be incorrectly triggered when creating a new FGFDMExec instance with an existing property manager.
• FGCondition now returns better (more explicit) exception messages
• The debug_lvl variable can now be modified to set the amount of information logged in the console:

import jsbsim

jsbsim.FGJSBBase().debug_lvl = 0 # disable debug information in the console

Developer

• The example C++ file JSBSim_minimal.cpp has been updated to compile with the current API.
• Removed a compilation warning about a comparison between signed and unsigned
• FGMassBalance is no longer having a pointer to FGGroundReactions
• Documentation build is now disabled when -DBUILD_DOCS=OFF is passed to CMake
• Updated .gitignore with Clion project files and Python cache files
• FGMatrixException now inherits from std::runtime_error
• The minimal version of CMake is now 3.1
• Build Doxygen documentation even when Python is not available
• The generation of the Python API documentation has been fixed (issue JSBSim Python API documentation unavailable! #373)

[bcoconni]

Release 1.1.4

JSBSim version 1.1.4 is a bug fix release.
Release Date: Jan 24, 2021

Changelog

• Fixed the build of the documentation of JSBSim Python API (issue JSBSim Python API documentation unavailable! #373)
• Fixed the source package of JSBSim Python module. The source package in 1.1.3 could not build on Windows and MacOSX.

[bcoconni]

Release 1.1.5

JSBSim version 1.1.5 is a bug fix release.
Release Date: Feb 05, 2021

Changelog

• Fixed the source package of JSBSim Python module. The source package in 1.1.4 could not build on Windows/Python 3.9 (issue Building the Python package from source fails for Windows/Python 3.9 #391).

[bcoconni]

Release 1.1.6

JSBSim version 1.1.6 is a maintenance release.
Release Date: Apr 30, 2021

Changelog

User

• New properties propeller-power-ftlbps, propeller-torque-ftlb and propeller-sense for Propeller power, torque, and sense (PR Properties added for Propeller power, torque, and sense #394)
• Fixes segmentation faults, a delta-wing Lift_alpha and Drag_alpha problem in aeromatic++ (issue AeromatiC++ Segmentation fault #400)

Developer

• Always set useDefault to false when calling SGPropertyNode::tie() (issue Always set useDefault to false when calling SGPropertyNode::tie() #363)
• Fixes build with recent versions of MinGW64 (issue Failing to build with MinGW64 on Windows #397)
• Fix ws2tcpip.h casing for cross compilation.

[bcoconni]

Release 1.1.7

JSBSim version 1.1.7 is a maintenance release.
Release Date: Jul 14, 2021

Changelog

User

• Mass flows can now be specified using SI unit (kg/s)
• Fixes issues where propellers were reported:
  • to generate high torques while being motionless or,
  • to unexpectedly spin in mild wind conditions.
• [Python] The methods load_ic and load_script now raise a FileNotFoundError exception when called on non existing files. This avoids the Python interpreter being killed when specifying a wrong path (or filename) to these methods.
• Adds a new property propulsion/fuel_freeze to freeze fuel consumption (PR Add propulsion/fuel_freeze property #462). This can be used for simulations that require the aircraft mass to remain constant.
• Adds a new flag DONT_EXECUTE_RUN_IC that can be specified to FGFDMExec::ResetToInitialConditions (PR Provide mode flag to ResetToInitialConditions() to skip the execution of RunIC() #466). When specified, this flag avoid calling FGFDMExec::RunIC when FGFDMExec::ResetToInitialConditions is executed.
• Fixes an error in the F-15 model where the kinematic element was not connected to the elevator position (PR Kinematic element wasn't connected to elevator position #471)

Aeromatic++

• Fixes lift curves for delta wings (issue Aeromatic alpha value output #436 / PR Fix delta wings #450)
• Samples input files are now provided for aeromatic++ in the folder utils/aeromatic++/samples/ (PR New config files for AeromatiC++ #453)
  • These sample files are distributed with the Windows installer JSBSim-1.1.7-setup.exe
• Fixes a bug which avoided engine data to be generated (issue Aeromatic alpha value output #436 / PR Fix systems #458)

Developer

• [Python] Both signatures of FGFDMExec.load_ic are now tested.
• Improves the release message
• Uses GitHub default TOC (table of contents) for Markdown documentation rather than providing our own (ugly) one.
• Avoids building JSBSim with Python 3.10 since this new version of the language will not be released until October 2021.

[bcoconni]

Release 1.1.8

JSBSim version 1.1.8 is a maintenance release.
Release Date: Jul 24, 2021

Changelog

User

• Add an interface to Matlab (PR Simulink integration  #445)
• Fix a bug in <linear_actuator> that resulted in erroneous output values when oscillating around the zero value (issue Linear Actuator behaving strangely #485)
• Update the Windows installer to distribute the files needed to build the interface with Matlab

Developer

• Improve test coverage for FGQuaternion
• Restore automatic deployment of the wheels for Python 3.9
• Deployment now need the build for MinGW32 to succeed
• Add a unit test for FGPropertyValue and FGTable
• Add an assert that forbids to set the value of FGPropertyValue when the property was specified with a minus sign
• Add a regression test for issue Linear Actuator behaving strangely #485
• Expand the message of the exception that is raised when not providing a value or a property to FGParameterValue.

[bcoconni]

Release 1.1.9

JSBSim version 1.1.9 is a maintenance release.
Release Date: Nov 07, 2021
Python version: 3.6 or higher

Changelog

User

• Fixed an error which prevented the equatorial and polar radii from <planet> to be propagated to the initial conditions.
• The header files needed to build the Matlab S-Function are now included in the Windows installer (issue Setting up the JSBSim interface to Matlab on Windows #491).
• The planet radii in <planet> can now be specified by the tags <equatorial_radius> and <polar_radius> which are more self explanatory than <semimajor_axis> and <semiminor_axis> (which are still valid).
• The support of Ubuntu Xenial 16.04 has been dropped: JSBSim packages for this version of Ubuntu are no longer released.
• Improved the error messages returned by FGTable: the file name and line number where the error occurred are now printed.
• Check the number of <input> tags for flight controls such as <pure_gain> (issue <pure_gain>: no error messages #497). This avoids a crash when some or all <input> elements are missing.
• JSBSim now accepts 2 sign conventions for the cross product inertia (xy, xz, yz) in <mass_balance> (see PR Fixed inertia matrix error #502). The sign convention is specified by the parameter negated_crossproduct_inertia which defaults to true for backward compatibility.
• The attribute negated_crossproduct_inertia is now specified in the JSBSim models that are using non zero cross product inertia.
• Turbine engines can now windmill even before they start (issue FGTurbine don't start windmilling until powered up at least once #494 and PR Ensure non-zero acceleration of N1/N2 for windmilling when N1/N2 = 0 #509).
• Fixed a sign error in the computation of aero/h_b-mac-ft (PR Fixed property "aero/h_b-mac-ft" algorithm error #508 )
• Example scripts and aircraft data (as well as their engines and systems) are now included in the Python wheels (issue A/C data file #337). They can be accessed from the Python module using the new function jsbsim.get_default_root_dir().

Developer

• Added a regression test for the <planet> feature.
• Expanded the unit test of FGTable. It now checks:
  • Initialization from XML
  • Table names using the prefix #
  • 3D tables
  • Error handling.
• Fixed a bug where FGTable instances were not untied from the property manager during their destruction. This could lead to segmentation faults when the property manager was later destroyed.
• Exceptions raised by FGTable are now instances of the TableException class.
• A minimum Python version is now specified for the binary wheels (currently 3.6 or higher).
• The Python script setup.py is no longer changing the current directory.
• The flag INSTALL_PYTHON_MODULE has been renamed INSTALL_JSBSIM_PYTHON_MODULE. The former being too generic, this avois potential name clashes with other modules.
• Two new scripts have been added in the admin folder:
  • XML_mass_update.py which allows automatically updating selected XML files in the aircraft data. It has avoided manual updates for the aircraft models which have been updated with the new XML attribute negated_crossproduct_inertia.
  • prepare_test_release.sh which modifies JSBSim to dry run a test release 0.99.xx to be published to TestPyPI

[bcoconni]

Release 1.1.10

JSBSim version 1.1.10 is a bug fix release.
Release Date: Nov 12, 2021
Python version: 3.6 or higher

Changelog

User

• Added the Matlab example files (TestJSBSim.m and ex737cruise.slx) in the Windows installer JSBSim-1.1.10-setup.exe to allow the user testing the S-Function once it is built.
• Provide Python package for Python 3.10
• Fixed an error where JSBSim could not autodetect the location of the bundled aircraft data (issue A/C data file #337)

Developer

• The XML validation schema for scripts has been updated. All scripts are now validated against this schema when a GitHub Action is triggered.

[bcoconni]

Release 1.1.11

JSBSim version 1.1.11 is a maintenance release.
Release Date: Feb 13, 2022
Python version: 3.6 or higher

Changelog

User

This is the last release of JSBSim that supports Python 3.6.
Python 3.6 has reached its end of life and is no longer supported by the Python Foundation (see PEP494). Please upgrade to Python 3.7 or higher.

• Output files are now written in the current directory instead of being written in the aircraft folder (issue A/C data file #337)
• The uninstall of Python wheels now completely removes the directory structure that was created during the installation of the aircraft data.
• A new exception TrimFailureException is now thrown when trim fails. This eases the detection of the trim failure (previously the exception message needed to be checked).
• An exception is thrown when a latitude higher than 90 degrees is supplied to a <waypoint> control element (PR Added error handling in FGWaypoint in case a supplied or calculated l… #536)
• Fix the sign of the initial NED climb rate (property ic/gamma-deg) (PR Sign change for NED to climb rate #545)
• JSBSim now checks malformed data in <table> elements. Anything different than numbers and spaces/tabs will be rejected.
• Usage of <location> and <orientation> in engines is now officially dropped (PR Remove engine code that reads in position and orientation  #559, Remove output of engine location and orientation. Only thruster counts. #561 and Remove engine location and orientation elements #563). These elements were deprecated long ago in favor of the corresponding elements <location> and <orientation> in thrusters. Therefore the code removed is no-op.
• The computation of the initial rotation rates has been fixed (Issue Improper use of local frame rotation rate #553). Previously, the rotation rates could be initialized with extremely high values when the vehicle was spawned over the Poles. And for a given set of initial conditions, the initial rotation rates could have different values depending on the initial latitude at which the vehicle was initialized. This now fixed.
• [Windows] The script JSBSimSimulinkCompile.m that builds the MATLAB S-function is now set to be executed immediately after the installer JSBSim-setup.exe has been run and no longer need manual updates before being run.
• The precision with which values are transmitted thru a socket can now be set via the attribute precision such as <output precision="8"> (PR Allow output precision to be specified for socket output #579)

Developer

• Added 2 new methods to FGFDMExec: SetOutputPath and GetOutputPath to specify the path to which the output files will be written.
• Python method FGFDMExec.set_root_dir() no longer alters the aircraft, engine and system paths. This is now the same behavior than its C++ counterpart FGFDMExec::SetRootDir.
• All JSBSim exceptions now inherit from JSBSim::BaseException. There still exist std::string exceptions thrown by JSBSim. Cleanup is still in progress.
• JSBSim no longer calls exit() or abort(). Exceptions are thrown instead. This gives the calling application an opportunity to gracefully recover.
• The MATLAB S-Function is now tested on Windows and MacOSX in addition to Linux.
• As distutils will be deprecated for Python 3.11, the migration to setuptools has been started. There are still a number of distutils features which have no equivalent to setuptools so this is work in progress.
• Improved the ability of setup.py to be executed on multiple platforms (removed some hardcoded statements)
• SGPropertyNode:getName() is no longer used as it has been dropped from the official SimGear library. This allows remaining compatible with FlightGear.
• When <input> and <output> elements are read from a file, JSBSim now checks that the file can be read before reading it, otherwise an exception is thrown. This avoids SEGFAULTs.

[bcoconni]

Release 1.1.12

JSBSim version 1.1.12 is a maintenance release.
Release Date: Jun 26, 2022
Python version: 3.7 or higher

Changelog

User

• Improvements to the <table> element:
  • Better error handling and improved messages when an error is found.
  • <table> now accepts 1x1, 1xN and Nx1 shapes (issue Improvements to <table> #185).
• The XML schemas for scripts and systems have been updated to match the most recent JSBSim features.
• Accelerations with respect to the ECI frame (and expressed in the body frame) are now exported by the properties:
  • accelerations/uidot-ft_sec2
  • accelerations/vidot-ft_sec2
  • accelerations/widot-ft_sec2
• Rotational accelerations with respect to the ECI frame (and expressed in the body frame) are now exported by the properties:
  • accelerations/pidot-rad_sec2
  • accelerations/qidot-rad_sec2
  • accelerations/ridot-rad_sec2
• Clarified the legal notice as well as the license used by JSBSim and its dependencies.
• Temporary fix for issue Weather Balloon script crash #654: the balloon content can no longer reach 0.0 moles.
• The example script scripts/weather-balloon.xml now display the burst event.

Python module

• The minimum Python version is now 3.7
• The dependency of the Python module to setuptools has been removed.
• Fixed issue Cannot add extra arguments when inheriting FGFDMExec #611 - extra arguments can now be added to the constructor __init__ of a class inheriting from FGFDMExec.
• Fixed issue FGFDMExec.get_property_catalog() is supposed to take 0 arguments, but is says it needs exactly one #641 - the method FGFDMExec.get_property_catalog() no longer has arguments to match the signature of its C++ counterpart.

MATLAB S-function

• The documentation matlab/README.md for the MATLAB S-Function has been improved.
  • Added MacOS build instructions
  • Documented the version of MSVC used to compile the JSBSim library
• Added MacOS compile line for MATLAB S-Function in the script JSBSimSimulinkCompile.m
• Allow two engines
• Overrode script control through SFunction input
• Control input on scripts only when allowed
• Added XML script to config the I/O ports of s-function
• Added error handling and dynamic update of I/O ports
• Created optional second input for wind/turbulence
• Added read/write checks for nodes
• Weather input now loaded to JSBSim
• Updated simulink model ex737cruise.slx and ex737cruise_io.xml.

Aeromatic++

• Overhaul of the propeller code, the produced tables now matches published data quite close.
• Created a configuration file in metric units when the parameters are entered in metric units.
• Added the option to save the aerodynamics section and the external-force section into separate files.

Developer

• The Python module shall now be compiled with setuptools>=60.0.0
• Migrating the front-end of the Python module build process from setuptools to build (work in progress)
• The Python source package now includes the Cython source code jsbsim.pyx instead of the Cython output jsbsim.cxx. This allows having consistent input data if the local version of Cython is different than the one used by JSBSim while building the source package.
• Added an .editorconfig file to set coding conventions for editors.
• Progress has been made on the migration from distutils to setuptools (still work in progress).
• The JSBSim library can now be built as a DLL on Windows.
• JSBSim now builds and uses libexpat 2.4.8 (unless explicitely requested to use the system libexpat library).

[bcoconni]

Release 1.1.13

JSBSim version 1.1.13 is a maintenance release.
Release Date: Dec 03, 2022
Python version: 3.7 or higher

Changelog

User

• The license of libexpat is now included in the Windows installer and in the Python wheels.
• Input sockets that were broken on Windows have been fixed.

Python module

• The Python script JSBSim has been renamed JSBSim.py and now has the same features than the binary executable JSBSim.exe.
• Fixed the data folders that are installed along with the Python module: some aircraft sub-directories System and Engines were missing in the previous release (issue Aircraft's Systems sub-directories are missing in the wheel packages. #687)
• Python wheels for MacOSX are now provided as universal binaries for Python >=3.8 which allows using these binary wheels with Apple Silicon chips.
• Python wheels for Python 3.11 are now available.
• JSBSim Python module is now installed under a single folder including the licenses and the aircraft data. In the previous release, the files were scattered among several folders. This allows a cleaner installation and removal (PR Build a proper Python package #755).
• Type hints are now provided along with JSBSim Python module (as per PEP 561 and PR Add types hints to the Python module #756).
• Usage of uninitialized instances of JSBSim classes now throws an exception to avoid a crash of the Python interpreter.
• eTemperature and ePressure are now derived from the Python module enum.
• Some internal methods are no longer accessible. Their names were prepended by the double underscore __ which according to Python programming guidelines are meant to be private methods. So you were warned !

MATLAB S-Function

• By default, the S-Function is now compiled using the flag JSBSIM_STATIC_LINK since JSBSim is supplied as a static library in the Windows installer (PR MEX build issue on Windows #735).

Developer

• Removed the Messages feature as it was unused and was using a static member that could lead to a segmentation fault when using several instances of FGFDMExec (issue Support for run JSBSim instance in multi-thread environment #666)
• Restored the automatic rebuild of the Python module that should occur when the headers included in jsbsim.pyx are modified.
• Replaced CMAKE_SOURCE_DIR by PROJECT_SOURCE_DIR to allow JSBSim being built using CMAKE FetchContent (issue Prefer PROJECT_SOURCE_DIR over CMAKE_SOURCE_DIR #684)
• The dependency to the win32api module has been removed to build JSBSim Python module on Windows.
• Random number generation is now made using C++11 standard library. This allowed removing another static member (issue Support for run JSBSim instance in multi-thread environment #666)
• Fixed a bug that prevented building JSBSim as a DLL using the MinGW compiler (issue DLL linking fails with MinGW32 #719)
• Unit tests have been added for the following classes: FGRealValue, FGParameter, FGParameterValue, FGCondition.

[seanmcleod]

What's with the release date of 3 Dec 2022?

[bcoconni]

What's with the release date of 3 Dec 2022?

Nothing, I was just considering to write the changelog to prepare the release of version 1.2.1 but discovered in the process that the changelog of 1.1.14 had not been written. So I've written the changelog of 1.1.14 and updated this discussion accordingly (the first post always contains the last release and the previous release message is moved to the tail of the discussion thread, hence this new post about 1.1.13).

So the changelog of 1.2.1 remains to be written and I'll post a message to suggest the release of 1.2.1 to the community. I'll suggest to base version 1.2.1 on the commit b420d44 which is the last commit before the logging system revamp.

And before one asks, the changelog of 1.2.0 is not written either but this one will be more complex to prepare: the diff with respect to 1.1.14 need a more elaborate use of git (it is not a simple matter of reading the recent git history).

[seanmcleod]

Ah, I missed the latest 1.1.14 at the top. When I clicked on the Github link from the notification email it landed me at 1.1.13, and I scrolled briefly up to see 1.1.12 so assumed 1.1.13 was the latest, which made me question the old date. So all good 😉

[bcoconni]

Release 1.1.14

JSBSim version 1.1.14 is a maintenance release.
Release Date: Nov 04, 2023
Python version: 3.7 or higher

Changelog

User

• A planet XML definition file can now be loaded using FGFDMExec::LoadPlanet() or the argument --planet=<filename> of the JSBSim executable (PR Add a LoadPlanet method to FGFDMExec #913)
• The MSIS model of the Earth atmosphere can now be selected instead of the International Standard Atmosphere model (PR Enable the usage of the NRLMSIS00 atmospheric model. #941 and PR Update the FGMSIS class #916)
• Added the ability to specify external forces in the inertial frame (PR Adding capability to aim external forces in inertial frame; added exa… #962)
• Fixed a bug where the speed of sound could be used uninitialized in FGPropeller.
• Fixed a bug where number parsing silently failed due to the decimal separator being set to the comma , by the locale while the XML files are using the period . (PR Locale independent numbers parsing #799).
• Fixed a bug where the ambient pressure could reach 0.0 and make JSBSim crash (PR Avoid non physical values for the ambient pressure and temperature #836 and Clarify the code intent #839)
• Fixed a bug where the version of an initial conditions XML file could be reported as being infinite. As JSBSim behavior is to default the version to 1.0 when it is unspecified, the version is now set accordingly (PR Fix discovery of document version number #845)
• Fixed a bug where the initial value of the wind velocity in the down direction was not converted from knots to ft/sec (PR Fix wind initial conditions #855)
• Fixed a bug where the equivalent airspeed velocity (VEAS) was using the local air density instead of the standard sea level density (PR Correct VEAS to use standard day SL density #900 and PR Use standard day SL density for VEAS in FGInitialCondition. #909).
• Clarified the warning message issued for already defined properties (PR Avoid misleading messages about properties being already defined #864)
• The support of Ubuntu Bionic 18.04 has been dropped: JSBSim packages for this version of Ubuntu are no longer released.
• The Windows installer now installs JSBSim in the folder %LOCALAPPDATA% by default. In most cases %LOCALAPPDATA% resolves to C:\Users\<user name>\AppData\Local (see The python example has fdm.FGFDMExec twice, with different explanations #798 (comment) for details).

Distributed flight dynamics models

• New aircraft 787-8 and global5000 have been added to the models distributed with the Python module.
• The roll autopilot of c172x has been fixed

Python module

This is the last release of JSBSim that supports Python 3.7.
Python 3.7 has reached its end of life and is no longer supported by the Python Foundation (see PEP537). Please upgrade to Python 3.8 or higher.

• Python wheels for Python 3.12 are now available.

Aeromatic++

• Better handling of input errors or inconsistencies to avoid erroneous outputs such as negative point masses (PR Aeromatic fix inputs #860 and PR Fix a mistake in e1af7cea6ce6dfc35cad99a005df6cce66a0b328, no engines… #954)

Developer

• The year in copyright notices in files *.in that are distributed by the Python module are now automatically updated.
• The Python docs can now be generated even if the JSBSim module has been installed by pip rather than having been built locally.
• Fixed a debug message in FGActuator that reporting a pointer address rather than the name of the <lag> element.
• Removed the BASE flag from string_utilities.h (PR Remove the flag BASE from string_utilities.h #837)
• Fixed #include of expat.h (PR Better #include for expat.h #838) to avoid build failure for some compilers.
• Unit tests have been added for the following class: FGAtmosphere (PR Add a unit test for FGAtmosphere #857)
• Improved the build process of the Python module by avoiding mutual dependencies of the CMake process and the setup.py script (PR Updating the Python module build #866)
• Moved the Mach/VCAS conversion methods to FGAuxiliary (PR Move the Mach/VCAS conversion methods to FGAuxiliary #898).
• Simplified the class FGLGear by removing its inheritance from FGSurface (PR FGLGear doesn't need to inherit from FGSurface. #884) and removed dead code from FGSurface (PR Remove dead code from FGSurface #907) in the process.
• Python wheels are now uploaded to PyPI using a Trusted Publisher (i.e. our GitHub project) rather than the less reliable pair of password/username.
• FGAtmosphere properties can now be unbound to allow switching the atmospheric model (PR Unbind FGAtmosphere properties #902 and PR Do not store the result of FGFDMExec::GetAtmosphere(). #908)
• Some maintenance and minor changes (PR Maintenance / Minor changes #952)
• Fixed some bugs in the CMake files
  • C++ Source files were duplicated in the folder python/
  • Use choco install in replacement of cinst which is no longer recognized on recent Windows runners.

[bcoconni]

Release 1.2.1

JSBSim version 1.2.1 is a maintenance release.
Release Date: Aug 08, 2024
Python version: 3.8 or higher

Changelog

User

• Fixed a bug in the computation of orbital parameters where the perigee argument was valid only if the inclination and eccentricity were non-zero (PR Argument of perigee only valid if both inclination and eccentricity are non-zero #981)
• Restored the ability to use the linearization feature from the console and from XML scripts (PR Linearization from console executable and xml script  #991). As a result of this change, the script 737_cruise_steady_turn_simplex.xml no longer fails.
• Fixed an error in the computation of rotation rates in the body frame (aka vPQRdot) (regression test added by PR Wrong calculation of vPQRdot in FGAccelerations class #1034 and fixed by PR Fix a mistake in vPQRdot calculation #1036)
• The documentation has been updated regarding the values that the mixture of a piston engine can be set to (PR Documentation updates. #1048 and issue Fixing the mixture for JSBSim piston aircraft #1037).
• Fixed a bug where a telnet connection could not be reopened (PR Provide possibility to reopen telnet connection #1078)
• Added the ability to change the location of thrusters via properties (PR Added ability to dynamically change thruster location via property #1073)
• The error management in socket code has been improved to intercept and report more errors. This should help the user finding errors more easily when using this feature (PR Some improvements to the socket code. #1081)
• Added the ability to modify the property ic/vw-mag-fps i.e. the initial value of the wind velocity magnitude (PR Add support for setting ic/vw-mag-fps #1093)
• Reduced the console output when debug level is zero (PR Reduce console output when debug level is zero #1092)
• The thrust augmentation command is now clamped to the range [0.0 - 1.0] (PR AugmentCmd should be clamped to [0.0..1.0] for 'augmentation method two' #1090)
• Added properties AGL-ft to display the height above the ground of each contact (PR Create AGL property for contacts #1104)
• Clarified the document of <function> to state that it can contain a single <table> element (PR Update FGFunction documentation #1131)

Distributed flight dynamics models

• The model of the Short S23 Empire has been updated.
• Fixed the initial conditions of the script ball_orbit.xml so that its orbit gets circular (i.e. its eccentricity is zero). See discussion Ball script circular orbit setup #985 for more details.
• The model of the Zeppelin NT airship a.k.a ZLT-NT has been updated.
• The model of the Submarine Scout airship has been updated.
• The license of the following files have been changed from GPLv2+ to LGPLv2.1+
  • systems/airship-mooring.xml
  • systems/airship_added_mass.xml
  • systems/hydrodynamic-planing-floats.xml
  • systems/hydrodynamic-planing.xml
  • systems/hydrodynamics.xml
  • systems/visual-reference-point-extensions.xml

Python module

• Improved the caching of property nodes for faster lookups (PR Use cached PropertyNodes in python API for property reads #993)
• The reference counting of property nodes is now shared between the C++ code and the python module. This avoids crashes due to the inadvertent deletion of pointers by the C++ code of pointers that are also used by the Python module. (PR Make the Python binding of FGPropertyNode compatible with SGSharedPtr ref counting #1000)
• Fixed the documentation of the methods FGPropertyNode.get_double_value and FGPropertyNode.set_double_value (PR Documentation updates. #1048 and issue CMAKE Configure Error on MacOS (M1 aarch64) #922).
• Made the Python module compatible with NumPy 2.0 (PR Fix incompatibilities with NumPy 2.0 #1107)

Aeromatic++

• Fixed a typo in a message printed in the console by aeromatic++ (PR Fix typo in Aeromatic++ #1002)
• Fixed the headers so that aeromatic++ can also be compiled with VS2015 (PR fix: toupper is not a member of std #1020)

Developer

• The CMake target libJSBSim now includes the list of the headers it uses for cross reference in other CMake files (PR fix: target include directories #1022).
• Some maintenance / minor changes have been done (see PR Maintenance / Minor changes #1031 and PR Maintenance / Minor changes #1050 for details).
• Replaced hardcoded buffer lengths by a computation of the length using sizeof(). This avoids potential mismatches in future updates of the files (PR Ensure consistent buffer size for snprintf #1035).
• JSBSim is now compiled and tested on MacOS M1 runners (PR Run tests on M1 MacOS runners. #1030)
• libexpat has been updgraded to 2.6.2 (PR Upgrade libexpat to 2.6.2 #1080)
• The XML element of late bound properties is now released after successful binding for memory saving (PR Release XML element when property value node was bound #1096)

[bcoconni]

Release 1.2.2

JSBSim version 1.2.2 is a maintenance release.
Release Date: March 22, 2025
Minimum Python Version: 3.8

Changelog

User

• VT code-based highlighting is now supported on Windows (PR Enable VT code based highlighting on Windows if supported #1146), allowing JSBSim to display colored output in the terminal.
• Improved error handling to prevent uncaught C++ exceptions that could unexpectedly terminate the calling program (PR Fix exceptions thrown by FGFunction and caught by FGAerodynamics #1152 and PR Handle properly the exceptions returned by FGCondition #1244).
• Fixed a memory leak that occurred when JSBSim failed to load a model due to errors in the <distributor> component (PR Memory leak fix and general improvements of FGDistributor #1245).
• Added a new function <roundmultiple>, which rounds a number to the nearest multiple of a given value (PR Add roundmultiple function #1170).
• Fixed a bug that prevented real-time execution after a reset (PR Prevent time catch up in real time mode #1213).
• Fixed a bug where number parsing silently failed due to the locale using a comma , as the decimal separator, while XML files require a period . (PR Fix locale dependent number parsing #1229).
• Reverted the FlightGear network protocol to v24 (PR Revert the FlightGear network protocol to v24 #1234), resolving several issues that caused broken network connections between JSBSim and FlightGear.

Distributed Flight Dynamics Models

• Moved AH1S-specific rotor/thruster definitions to the helicopter's directory (PR Move AH1S specific rotor/thrusters to aircraft's directory #1167).

Python Module

This is the last JSBSim release to support Python 3.8.
Python 3.8 has reached end-of-life and is no longer supported by the Python Foundation (see [PEP 569](https://www.python.org/dev/peps/pep-0569/)). Please upgrade to Python 3.9 or newer.

• Python dependencies are now listed in the standard requirements.txt file located in the python folder (PR Manage Python dependencies in requirements.txt #1177), enabling installation with the command:
  pip install -r python/requirements.txt
• Fixed a bug where using the --planet argument would terminate the Python JSBSim script (PR fixing argparsing of planet file #1215).

Developer

• Fixed incorrect variable types used by some properties in FGFDMExec, which could cause JSBSim to crash when running on PowerPC systems (PR Consistency for some FGFDMExec properties #1166).
• Made the method FGInertial::GetGM const (PR Make FGInertial::GetGM const #1175).
• Fixed an uninitialized variable in GeographicLib that caused numerical overflows and intermittent CI workflow crashes (PR Fix an uninitialized variable in GeographicLib. #1173).
• Added bounds checking in FGFCS (PR fix some bounds checks in FGFCS #1191).
• Removed multiple using namespace std; statements from header files, in accordance with good coding practices (PR Fix: Don't polute global namespace with std. #1193).
• Fixed an error in string_utilities.h that prevented JSBSim from compiling with Cygwin (PR Cygwin build fix #1200).
• Updated GitHub runners to drop deprecated OS versions: macOS (PR Upgrade macos-12 runners to macos-13. #1197) and Ubuntu (PR Ubuntu update for CI workflows #1231).
• Updated the unit test TestInputSocket.py to use telnetlib3, replacing the now-deprecated standard library telnetlib (PR Replace the obsolete library telnetlib #1228).

[bcoconni]

This release note is for the record. The most up to date release notes are in the first message of this discussion thread.

Note: I took the opportunity to update the release notes of the GitHub files for v1.2.3.

[bcoconni]

Release 1.2.3

JSBSim version 1.2.3 is a maintenance release.
Release Date: June 7, 2025
Minimum Python Version: 3.9

Changelog

User

• Ubuntu packages are now built for Ubuntu Jammy 22.04 and Ubuntu Noble 24.04. Ubuntu packages for Focal 20.04 are no longer built.
• Fix: Turbulence wind velocities are now zeroed when turbulence is disabled. Previously, turbulence values retained their last computed (non-zero) values when turbulence was disabled (PR Reset turbulence vector when turbulence is disabled #1252).
• New: A separate random seed (property atmosphere/randomseed) can now be used for the random number generator used by turbulence. By default, turbulence uses the overall random seed simulation/randomseed unless a value is set for the property atmosphere/randomseed (PR Allow for a separate random seed for wind turbulence #1253).
• New: Sensors can now have their own random seed (property randomseed of a given sensor). By default, sensors use the overall random seed simulation/randomseed unless a value is set for their property randomseed (PR Sensor random seed #1254).
• Fix: Turbine engines were not updating some of their input values before computing their parameters. This could lead to unexpected behavior in certain situations (PR FGTurbine does not update the thruster inputs before calling FGThruster::Calculate #1259).
• Fix: Fixed the mixture and throttle settings to allow piston engines to start using the property propulsion/set-running (PR Ensure engine set-running works for piston engines #1266).
• Fix: Corrected some errors in the Python module documentation (PR Fix the docs generation for the Python module #1276).

Python Module

• Python 3.8 is no longer supported. The minimum supported version is now 3.9.
• New: Improvements to the Python classes (PR Improvements to the Python module #1275):
  • Added methods get_attribute() and set_attribute() to the class FGPropertyNode, allowing users to get/set the read/write attributes of properties.
  • Added the method get_aircraft_name() to the class FGAircraft, which retrieves the full aircraft name (the one specified in the XML element <fdm_config name="..."/>).
  • Added an equality operator between instances of FGPropertyNode to check if they point to the same property node.
• Fix: Type hinting has been corrected. IDEs that use type hinting to autocomplete classes and functions in the JSBSim Python module should now work properly (PR Fix type hinting for the Python module #1287).

Examples

• Following the bug fix for piston engines, Python examples now use the property propulsion/set-running to start the engines (PR Unify engine init logic; update TrimEnvelope limits #1267).
• Added an example demonstrating how to implement thrust vectoring with JSBSim (PR Add a thrust vectoring python script example #1280).

Developer

• JSBSim now uses C++17.
• JSBSim now builds and uses libexpat 2.7.0 (unless explicitly requested to use the system libexpat library) (PR Upgrade libexpat to 2.7.0 #1247).
• The class FGPropertyNode has been removed to prevent illegal type conversions (PR Remove the class FGPropertyNode #1270).
• Some maintenance and minor changes have been made (PR Maintenance / Minor changes #1272).
• The .vcxproj C++ toolset now uses MSVC 2022 (v143) (PR [skip ci] Upgrade .vcxproj C++ toolset to VS2022 (v143) to match CI pipeline #1293).
• Fixed a number of warnings issued by the most pedantic compilers (PR Fix warnings from new compilers #1291).

[bcoconni]

This release note is for the record. The most up to date release notes are in the first message of this discussion thread.

[bcoconni]

JSBSim Latest Release: 1.2.4

• Download binary files
• Python packages are available on PyPI and can be installed with pip
• Conda packages are available via conda-forge. To install with conda, run: conda install -c conda-forge jsbsim

Release 1.2.4

JSBSim version 1.2.4 is a maintenance release.
Release Date: February 7, 2026
Minimum Python Version: 3.9

Changelog

User

• New: A new set of properties position/from-start-neu-n-ft, position/from-start-neu-e-ft and position/from-start-neu-u-ft has been added that gives the aircraft position in the NEU (North-East-Up) frame. The NEU frame is fixed with respect to the ECEF and its origin is located at the initial condition's latitude and longitude and zero altitude relative to the geoid ellipse (PR Add NEU (North East Up) properties for distance from IC start #1321 and Improve NEU properties #1327)
• Improvement: Optimized calls to SGProperty in the atmosphere model for some small speed improvement (PR Optimize calls to SGPropertyNode::getNode in FGAtmosphere::Calculate #1382)
• Fix: The turbine engine throttle position ThrottlePos was uninitialized resulting in odd behavior until the throttle position was updated (PR fix uninitialized ThrottlePos in FGTurbine #1297)
• Fix: Output in the KML format now uses the geodetic altitude instead of the geocentric altitude.
• Fix: Removed hard coded references to /fdm/jsbsim which could result in some output errors when several instances of JSBSim were using the same instance of FGPropertyManager (PR Remove hard coded references to /fdm/jsbsim/ #1381)

Python Module

This is the last JSBSim release to support Python 3.9.
Python 3.9 has reached end-of-life and is no longer supported by the Python Foundation (see PEP 596). Please upgrade to Python 3.10 or newer.

Flight Dynamics Models

• Fix: The F450 UAV throttle command has been fixed so that it responds to standard commands such as fcs/throttle-cmd-norm. (PR Fixed f450 example: engine rpm is zero when low fps #1323)
• Fix: The J246 rocket is now using standard orbital parameters orbital/eccentricity, orbital/apoapsis-radius-ft and orbital/periapsis-radius-ft for better accuracy (PR Edit J246 aircraft guidance properties #1377)

Examples

• New: Python examples can now be run on Google Colab using a simple link. No installation needed. (PR Add a cell to enable running on Google Colab and related readme change (#1305) #1309, Add detailed comments for python example files (#1308) #1314 and [skip ci] Notebooks improvements #1331)
• Improvement: The example "AoA vs CAS" has been improved with a better introduction, new figures and improved plots. (PR Add a thrust vectoring python script example #1280 and Example AoA vs CAS, credits updated #1384).

Developer

• Fixed illegal function pointer conversion (PR Fix illegal function pointer conversions #1304, Update FGStandardAtmosphere bindings to avoid function pointer casts #1311 and Clean up the properties code and Tie methods. #1317)
• Fixed conversion of enum to raw values (PR Add raw values enumeration to fix segfaults #1312)
• Set editor's defaults to trimming trailing whitespaces (PR Add trim_trailing_whitespace to .editorconfig [skip ci] #1332)
• Set CMake minimum version to 3.15 (PR Synchronize CMake min version with the overall project. #1335)
• Aircaft XML definition are now validated by the CI workflow (PR Validation of aircraft XML definition file #1038)
• MacOS 13 GitHub runners have been sunset (PR Address the sunset of macOS 13 runners. #1355)
• Fixed the failure of TestActuator.py due to some API deprecation in SciPy (PR Fix the failure of TestActuator.py due to some deprecations in SciPy #1376)