Install Jsbsim

Install JSBSim

JSBSim is an open-source flight dynamics model (FDM) library — real airspeed/lift/drag/stall aerodynamics, not a rigid-body approximation. It's used as a swappable "plant" behind INAV's MSP_SIMULATOR/HITL sensor-injection path (see jsbsim-sitl-testing skill) to give SITL tests full aerodynamic behavior instead of the built-in simple physics.

This skill is standalone: it only installs and verifies the JSBSim Python package. It doesn't assume any particular test harness — use it any time a test needs real aerodynamics, independent of inav-sitl-bench.

Quick Start

pip install jsbsim
python3 -c "import jsbsim; print(jsbsim.__version__)"

Expected output: a version string, e.g. 1.2.3. That's the whole install — no license, no GUI, no extra system packages needed.

What Gets Installed

pip install jsbsim pulls a self-contained wheel: a compiled extension module (jsbsim/_jsbsim.cpython-<ver>-<arch>.so) plus bundled aircraft/engine XML data under jsbsim/aircraft/ and jsbsim/engine/ in site-packages. It depends only on numpy. There is nothing else to configure — the extension does not dynamically link against or require a system-installed JSBSim.

Common Pitfall: Ignore the apt jsbsim/jsbsim-devel Packages

Some systems (including this one) also have jsbsim and jsbsim-devel available via apt/dpkg. These are unrelated to the Python workflow and installing them is not necessary. Verified empirically on this machine:

• The apt jsbsim package installs /usr/bin/JSBSim (a standalone C++ CLI) and /usr/bin/aeromatic.
• The apt jsbsim-devel package installs C++ headers under /usr/include/JSBSim/.
• The pip jsbsim Python package (pip show -f jsbsim) ships its own compiled _jsbsim*.so and does not reference /usr/include or /usr/bin — it's fully self-contained.

If you see both installed on a shared machine, that's most likely leftover from someone using the JSBSim CLI directly for something unrelated — don't treat it as a prerequisite for pip install jsbsim, and don't install the apt packages just because a install guide for the C++ library mentions them.

Verification Checklist

python3 -c "
import jsbsim
print('version:', jsbsim.__version__)
fdm = jsbsim.FGFDMExec(None)
fdm.load_model('c172p')   # bundled example aircraft
print('loaded c172p OK')
"

If this prints loaded c172p OK, the install is fully functional — model loading exercises the bundled aircraft-data path, not just the import.

Troubleshooting

Related Skills

• jsbsim-sitl-testing — using JSBSim as the physics plant for closed-loop INAV SITL testing (inav-sitl-bench)
• build-sitl — build INAV SITL firmware