From: Jon S. Berndt <jonsberndt@co...> - 2011-06-22 12:56:57
I'm working on modifying the interface between JSBSim and FlightGear to work
with the new JSBSim standard atmosphere model. There are two or three ways
that the atmosphere model can be modified by the calling application:
A temperature bias can be added to the entire temperature profile (from sea
level to high altitude) by using the SetTemperature() method:
SetTemperatureSL(double t, eTemperature unit=eFahrenheit)
SetTemperature(double t, double h, eTemperature unit=eFahrenheit)
Units supported are eFahrenheit, eCelsius, eRankine, eKelvin. Using one of
these will cause a bias to be calculated and used to modify the temperature
profile. Setting the temperature will cause the pressure calculations to be
A pressure can also be set using this methods:
SetPressureSL(double pressure, ePressure unit=ePSF)
Currently, only the sea level pressure can be modified. The available units
are: ePSF, eMillibars, ePascals, eInchesHg.
I may provide a way to set the pressure at an elevation.
Neither pressure altitude nor density altitude are currently being
calculated in the new standard atmosphere model - those will be added at
I should also add that with the new standard atmosphere model there is
another way to modify the standard atmosphere temperature profile, but that
would be done using properties and not through a standardized atmosphere API
For more information, see the JSBSim API documentation at
http://www.jsbsim.org/JSBSim/. The documentation has not been updated with the very
latest, but it is still very current.
Finally, note that the new standard atmosphere model has not quite yet been
integrated with FlightGear, but that should be possible in just a few days.
> I'm working on modifying the interface between JSBSim and FlightGear to
> work with the new JSBSim standard atmosphere model. There are two or three
> ways that the atmosphere model can be modified by the calling application:
since FlightGear has it's own atmosphere model, how will this cooperate with
the new JSBSim's atmosphere model? What we should try to avoid is to have two
competing models, one for the FDM and one for the other systems. Specially,
the altimetry springs to my mind, which caused some trouble in the past.
> Finally, note that the new standard atmosphere model has not quite yet been
> integrated with FlightGear, but that should be possible in just a few days.
May I ask to extend these "few days" until we created the release branch on
July, 17th? I'd really like to give your new model a try, but prefer to have
enough time for testing.