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Integrate Jet Propulsion data with an Aircraft Dynamics model

Modelon’s Jet Propulsion Library offers capabilities to compute and store on-design (sizing) data, like from Top Of Climb or Cruise, given an intended operating condition and performance.

These data-files can be stored, modified, and re-used in different models and then used as the sizing data when computing the performance in a dynamic simulation starting from an arbitrary operating point, for example when simulating take-off or landing.

In the following sections, this will be demonstrated by computing sizing data in a gas turbine rig-model from Jet Propulsion Library and then computing the performance in a system model representing a high performance aircraft from Aircraft Dynamics Library. But you can also choose to do it on your own model.

Generate OnDesign data🔗

Required libraries: Modelon Base 4.1, Jet Propulsion 2.4 build 3

If you already have a model from which you like to export on-design data from, proceed to step 2.

  1. Go to JetPropulsion.Experiments.MixedTurbofan.OnDesign. Right click and “Extend…” this model to your workspace. Name it e.g. MixedTurbofanOnDesign

  2. Go to the settings_JPL component (Note that the text says OnDesign) and set the following parameter:

    fileNameOut = "/home/jovyan/impact/workspaces/XML_JPL/model_libraries/editable/Workspace/Resources/MixedTurbofan.xml"


    Replace “XML_JPL” with the actual name of your workspace.

    This path decides where to store the on-design sizing data. For simplicity, we store the file in our workspace.

  3. Press the button to run the model. Depending on your IMPACT version, either a pop-up will appear, indicating that a new file has been created. Do NOT press reload until the simulation has finished fully. If no pop-up appears, just refresh your browser after simulation.

    You should now have the OnDesign simulation data.


    This file contains values for

    • Design point
    • Map scaling values
    • Start values for the numerical solver.

    The file can also be downloaded by hovering over the file and pressing the download button.

    <?xml version="1.0"?>

The OnDesign data file is now successfully generated!

Import to an off-design operating point🔗

Required Libraries: Modelon Base 4.1 , Jet Propulsion 2.4 build 3, Aircraft Dynamics, Electrification, Hydraulics, Pneumatics, Fuel System, Industry Examples


All of the libraries above are only needed in this particular model.

In this section we will import the previously generated on-design sizing data and run the gas turbine in a completely different operating point.

  1. Go to IndustryExamples.Aerospace.Aircraft.BalkedLanding. Right click and “Extend…” this model to your workspace. Name it e.g. BalkedLandingOffDesign

  2. The on-design sizing data is used to parameterize the full system model. To do this, we must locate the settings_JPL component and refer to the recently created XML-file. This model contains several hierarchical layers of components. To find the settings_JPL component (Note that the text says OffDesign), we need to dig deeper into the hierarchy. Inspect the aircraft component to aircraft.power.engine5 and set the following parameter in the settings_JPL component on the canvas:

    fileNameIn = "/home/jovyan/impact/workspaces/XML_JPL/model_libraries/editable/Workspace/Resources/MixedTurbofan.xml"


    Replace “XML_JPL” with the actual name of your workspace

    Alternatively, the user can drag the MixedTurbofan.xml file on top of the parameter field. This will autogenerate the following value:

    fileNameIn = Modelica.Utilities.Files.loadResource("modelica://Workspace/Resources/MixedTurbofan.xml")


    The parameter engineInstanceName and its value “aircraft.power.engine5.base” indicates the model path to the engine component. Ensure engineInstanceName is set to “aircraft.power.engine5.base”. In case you are using another model, this must be set to correctly use the value in the previously generated XML-file.

  3. Simulate the model. The design point is now taken from the XML created in the previous section. To verify that the BalkedLandingOffDesign model actually uses the recently created XML-file, you can search for “hpt.trb.NDes” and verify that the value is 14705.7 RPM. This value is the same as in the table on the previous section (<NDes>14705.7</NDes>).


In this tutorial we have shown how to compute the sizing in a gas turbine rig-model and then use this information in a dynamic simulation.

  • We have generated on-design sizing data from a single gas turbine model into an XML-file
  • We imported the sizing data into a full aircraft model
  • Ran the full system model with the on-design sizing data to calculate performance during a balked landing scenario