217 lines
8.2 KiB
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217 lines
8.2 KiB
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**************************
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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 **Plot / Export** button on the **Flight simulations** window.
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.. figure:: /img/user_guide/advanced_flight_simulation/PlotExportButton.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 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 **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:
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- Time
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- Altitude
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- Vertical velocity
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- Vertical acceleration
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- Total velocity
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- Total acceleration
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- Lateral distance
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- Lateral direction
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- Lateral velocity
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- Lateral acceleration
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- Latitude
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- Longitude
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- Gravitational acceleration
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- Angle of attack
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- Roll rate
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- Pitch rate
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- Yaw rate
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- Mass
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- Propellant mass
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- Longitudinal moment of inertia
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- Rotational moment of inertia
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- CP location
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- CG location
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- Stability margin calibers
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- Mach number
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- Reynolds number
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- Thrust
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- Drag force
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- Drag coefficient
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- Axial drag coefficient
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- Friction drag coefficient
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- Pressure drag coefficient
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- Base drag coefficient
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- Normal force coefficient
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- Pitch moment coefficient
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- Yaw moment coefficient
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- Side force coefficient
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- Roll moment coefficient
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- Roll forcing coefficient
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- Roll damping coefficient
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- Pitch damping coefficient
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- Reference length
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- Reference area
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- Vertical orientation (zenith)
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- Lateral orientation (azimuth)
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- Wind velocity
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- Air temperature
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- Air pressure
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- Speed of sound
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- Simulation time step
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- Computation time
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- Position parallel to wind
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- Position upwind
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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 **New Y-axis plot type** button, or delete parameters from the plot
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with the **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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Launch Conditions and Simulation Options
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========================================
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From the **Plot data** window, you can click the **<< Edit** button to configure **Launch conditions**, and
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**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 **Simulation options** tab, the **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 (*and frankly, beyond this author's knowledge!*).
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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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Exporting Data
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==============
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Located on the Plot / export panel, the 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 **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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