Compare Flights

This example demonstrates how to use the rocketpy CompareFlights class. This class has many applications, including the comparison of different flight setups for a single rocket, the simulation of deployable systems, and the multi-stage rocket analysis.

Importing classes

We will start by importing the necessary classes and modules:

from rocketpy.plots.compare import CompareFlights
from rocketpy import Environment, Flight, Rocket, SolidMotor
from datetime import datetime, timedelta

Create Environment, Motor and Rocket

First, let’s create the environment, motor and rocket objects. This is done following the same steps as in the First Simulation with RocketPy example.

after_tomorrow = datetime.now() + timedelta(days=2)
env = Environment(latitude=-23, longitude=-49, date=after_tomorrow)
env.set_atmospheric_model(type="Forecast", file="GFS")

cesaroni_motor = SolidMotor(
    thrust_source="../data/motors/Cesaroni_M1670.eng",
    dry_mass=1.815,
    dry_inertia=(0.125, 0.125, 0.002),
    nozzle_radius=33 / 1000,
    grain_number=5,
    grain_density=1815,
    grain_outer_radius=33 / 1000,
    grain_initial_inner_radius=15 / 1000,
    grain_initial_height=120 / 1000,
    grain_separation=5 / 1000,
    grains_center_of_mass_position=0.397,
    center_of_dry_mass_position=0.317,
    nozzle_position=0,
    burn_time=3.9,
    throat_radius=11 / 1000,
    coordinate_system_orientation="nozzle_to_combustion_chamber",
)

calisto = Rocket(
    radius=127 / 2000,
    mass=14.426,
    inertia=(6.321, 6.321, 0.034),
    power_off_drag="../data/calisto/powerOffDragCurve.csv",
    power_on_drag="../data/calisto/powerOnDragCurve.csv",
    center_of_mass_without_motor=0,
    coordinate_system_orientation="tail_to_nose",
)

calisto.set_rail_buttons(
    upper_button_position=0.0818,
    lower_button_position=-0.618,
    angular_position=45,
)

calisto.add_motor(cesaroni_motor, position=-1.255)

nosecone = calisto.add_nose(length=0.55829, kind="vonKarman", position=1.278)

fin_set = calisto.add_trapezoidal_fins(
    n=4,
    root_chord=0.120,
    tip_chord=0.060,
    span=0.110,
    position=-1.04956,
    cant_angle=0.5,
    airfoil=("../data/calisto/NACA0012-radians.csv", "radians"),
)

tail = calisto.add_tail(
    top_radius=0.0635, bottom_radius=0.0435, length=0.060, position=-1.194656
)

main_chute = calisto.add_parachute(
    "Main",
    cd_s=10.0,
    trigger=800,
    sampling_rate=105,
    lag=1.5,
    noise=(0, 8.3, 0.5),
)

drogue_chute = calisto.add_parachute(
    "Drogue",
    cd_s=1.0,
    trigger="apogee",
    sampling_rate=105,
    lag=1.5,
    noise=(0, 8.3, 0.5),
)

Creating the Flight objects

Now we can create different flights varying the launch angle and the rail inclination:

inclinations = [85, 75]
headings = [90, 135]
flights = []

for heading in headings:
    for inclination in inclinations:
        flight = Flight(
            environment=env,
            rocket=calisto,
            rail_length=5.2,
            inclination=inclination,
            heading=heading,
            name=f"Incl {inclination} Head {heading}",
        )
        flights.append(flight)

We can easily visualize the number of flights created:

print("Number of flights: ", len(flights))

Number of flights:  4

Start the comparison

It is easy to initialize the CompareFlights object:

comparison = CompareFlights(flights)

After the initialization, we can use different methods to plot the results in a comparative way. To see a full description of the available methods, you can check the CompareFlights documentation.

Plotting results one by one

The flights results are divided into different methods, so we can plot them one by one. This is practical when we want to focus on a specific aspect of the flights.

comparison.trajectories_3d(legend=True)

comparison.positions()

comparison.trajectories_2d(plane="xy", legend=True)

comparison.velocities()

comparison.stream_velocities()

comparison.accelerations()

comparison.angular_velocities()

comparison.angular_accelerations()

comparison.attitude_angles()

comparison.euler_angles()

comparison.quaternions()

comparison.angles_of_attack()

comparison.aerodynamic_forces()

comparison.aerodynamic_moments()

comparison.fluid_mechanics()

comparison.energies()

comparison.powers()

Plotting using the all method

Alternatively, we can plot the results altogether by calling one simple method:

comparison.all()

This method is not implemented yet

This method is not implemented yet