200 lines
8.9 KiB
ReStructuredText
200 lines
8.9 KiB
ReStructuredText
**************************
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Advanced Flight Simulation
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**************************
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OpenRocket offers more advanced options for simulating flight. You can plot your rocket's predicted acceleration, climb,
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eject and landing, make a prediction for how far downrange and in which direction your flight will land, and even
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experiment with different models of Earth's geometry, as it affects your flight. Once you're satisfied with a sim, you
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can export your data for analysis and charting in other packages.
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.. contents:: Table of Contents
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:depth: 2
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:local:
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:backlinks: none
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----
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Plotting your rocket's flight
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=============================
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To begin learning about OpenRocket's plotting features, first, click the :guilabel:`Plot / Export` button on the :guilabel:`Flight simulations` window.
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.. figure:: /img/user_guide/advanced_flight_simulation/PlotExportButton.png
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:width: 400 px
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:align: center
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:figclass: or-image-border
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:alt: The Plot / export Button.
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On the **Edit simulation** panel, you'll see tabs marked **Plot data** and **Export data**.
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Plotting data
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-------------
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The :guilabel:`Plot data` tab opens first. Here you can define many parameters that will determine what values are plotted, and
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what events are marked on the plot.
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.. figure:: /img/user_guide/advanced_flight_simulation/PlotExportWindow.png
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:width: 800 px
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:align: center
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:figclass: or-image-border
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:alt: The Plot / export window.
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Here you'll be able to quickly choose from a number of standard plots:
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.. figure:: /img/user_guide/advanced_flight_simulation/PlotConfigs.png
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:width: 806 px
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:align: center
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:figclass: or-image-border
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:alt: Standard plots
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You'll also be able to assign to the X and Y axes any one of over 50 parameters. If you click on the plot variable
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dropdown, you'll see a search box and a list of variable categories. You can either scroll through the categories
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to find the parameter you want, or type in the search box to filter the list:
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.. figure:: /img/user_guide/advanced_flight_simulation/ChoosePlotVariable.png
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:width: 806 px
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:align: center
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:figclass: or-image-border
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:alt: Select plot variable
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Select a plot variable from the variable groups (left), or search for the desired variable (right).
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The parameters are categorized in the
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following groups:
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- **Time**: Variables related to time
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- **Position and Motion**: Variables related to the position and motion of the rocket (e.g. altitude, position, velocity, acceleration)
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- **Orientation**: Variables related to the orientation of the rocket (e.g. pitch, yaw, roll)
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- **Mass and Inertia**: Variables related to the mass and inertia
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- **Stability**: Variables related to the stability of the rocket (e.g. CG, CP, stability margin)
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- **Thrust and Drag**: Variables related to the thrust and drag (e.g. thrust, TWR, drag)
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- **Coefficients**: Variables related to the calculation coefficients (e.g. normal force coefficient, roll moment coefficient)
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- **Atmospheric Conditions**: Variables related to the atmospheric conditions (e.g. air pressure, wind velocity)
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- **Characteristic Numbers**: Variables related to the characteristic numbers (e.g. Mach number, Reynolds number)
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- **Reference Values**: Variables related to the reference values (e.g. reference area, reference length)
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- **Simulation Information**: Variables related to the simulation information (e.g. simulation time step)
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- **Custom**: *(User-defined parameters)*
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You can assign multiple parameters to the Y-axis, and choose whether their scales appear on the left, or the right side
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of the plot. You can add Y-axis parameters with the :guilabel:`New Y-axis plot type` button, or delete parameters from the plot
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with the :guilabel:`X` buttons. (*The X-axis takes only a single plotted parameter, typically* **Time**).
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Additionally, you can choose from several flight events, any or all of which can be called out on your plot, in reference
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to the simulated time of occurrence.
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.. figure:: /img/user_guide/advanced_flight_simulation/YaxisTypes.png
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:width: 800 px
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:align: center
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:figclass: or-image-border
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:alt: Setting Y-axes and Events for plotting
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Plotted results
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---------------
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Below you can see a plot of *A simple model rocket*, simulation number 4, flying on a C6-5. Note that the five events
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checked in the above screen have been marked on the plot (*some very close to each other, or to the edge*):
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**Motor ignition**, **Motor burnout**, **Apogee**, **Recovery device deployment**, and **Ground hit**.
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You can also see that the three Y-axis parameters described above: **Altitude**, **Vertical velocity**, and
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**Vertical acceleration** appear as lines of three different colors.
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.. figure:: /img/user_guide/advanced_flight_simulation/PlotOfSimulation.png
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:width: 800 px
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:align: center
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:figclass: or-image-border
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:alt: A Plot of the simulation.
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As your rockets get more complex, with features like dual-deploy, air-start and multiple stages, your plots can grow in
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complexity to simulate their expected behavior. Below is a plot (*from the example rockets*) of a "High Power Airstart"
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rocket, modeled after a Patriot missile. The central motor starts on the launch pad, while the surrounding motors start
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while the rocket is in the air (*hence, an "airstart"*). The plot records the separate motor start events, and the
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deployment of both a drogue, and a main parachute.
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.. figure:: /img/user_guide/advanced_flight_simulation/ComplexPlot.png
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:width: 800 px
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:align: center
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:figclass: or-image-border
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:alt: A Plot of Sim #5 of the "High Power Airstart" example rocket.
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Notice what's happening in the plot above: The rocket is *losing velocity* - the blue line - before the airstart occurs.
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This is probably not what we want.
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However, simulation number 3 of the same rocket, below, has an earlier airstart, and looks like it should work as expected.
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Looking at the slight wiggle in the velocity curve, we could also try another simulation to provide a little bit more
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margin for error.
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.. figure:: /img/user_guide/advanced_flight_simulation/ComplexPlot2.png
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:width: 800 px
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:align: center
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:figclass: or-image-border
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:alt: A Plot of Sim #3 of the "High Power Airstart" example rocket.
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----
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Launch Conditions and Simulation Options
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========================================
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From the :guilabel:`Plot data` window, you can click the :guilabel:`<< Edit:guilabel:` button to configure :guilabel:`Launch conditions`, and
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:guilabel:`Simulation options` before you plot.
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Launch conditions
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-----------------
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OpenRocket can simulate conditions at the launch site, so you can estimate how winds will direct your flight, and how
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far downrange your rocket will drift.
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In the screen shown below, you can set parameters (and units) for wind, and for your **Launch site**, you can set the
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**Latitude**, **Longitude** and **Altitude**, as well as **Atmospheric conditions**. Note that Atmospheric conditions
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affect your rocket's ascent velocity, as well as the local `Speed of Sound <https://en.wikipedia.org/wiki/Speed_of_sound>`__.
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This is also the panel where you can set the length of your launch rod or rail. This length will affect whether your
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simulation *passes or fails*, when it's evaluated for minimum speed off the rod.
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.. figure:: /img/user_guide/advanced_flight_simulation/EditSimulationLaunchCond.png
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:width: 800 px
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:align: center
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:figclass: or-image-border
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:alt: The Edit simulation window: Launch conditions.
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Simulation options
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------------------
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In the :guilabel:`Simulation options` tab, the :guilabel:`Simulator options` let you choose the shape of the simulated Earth in your
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calculations (*doing so* **does not** *affect the Earth background in Photo Studio*), and you can choose the time-resolution
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of the simulation. This is also the place where you add and set up **Simulation extensions**, which are beyond this
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guide's purpose.
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.. figure:: /img/user_guide/advanced_flight_simulation/EditSimulationSimOpts.png
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:width: 800 px
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:align: center
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:figclass: or-image-border
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:alt: The Edit simulation window: Simulation options.
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The Simulation options in the simulation configuration window
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----
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Exporting Data
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==============
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Located on the :guilabel:`Plot / export panel`, the :guilabel:`Export Data tab` (shown below) helps you set up a Comma-Separated Value (.csv)
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formatted file to export data from your simulations. You can export any or all of over 50 values (generally speaking,
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the list of parameters above, plus **Coriolis acceleration**). Optional **Comments** sections list any flight events
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(**Apogee**, for example) you selected for your simulation, as well as description and field descriptions.
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You can choose separators other than comma, if you prefer semicolon, space, or TAB-delimited data. Once you have your
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data choices set up, clicking the :guilabel:`Export` button brings up a file dialog to choose a filename and location for your
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exported data.
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.. figure:: /img/user_guide/advanced_flight_simulation/ExportData.png
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:width: 800 px
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:align: center
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:figclass: or-image-border
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:alt: The Export data window.
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The Export data window.
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