rocketPy package¶

Submodules¶

rocketPy.components module¶

Creates the components of a rocket. Base classes and the specific useful components are created. All components inherit from Component From here, it splits into InternalComponent or ExternalComponent where the difference is used to help the drag model, and plotting.

class rocketPy.components.BodyTube(name='Body Tube', mass=None, inertia=None, diameter=None, length=None, wall_thickness=<Quantity(2, 'millimeter')>, material=None)[source]¶

Bases: rocketPy.components.ExternalComponent

CNa(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3, K=1.1)[source]¶

estimate_inertia()[source]¶: Generic method to estimate the mass of the component - assume inertia is 0. This method should be overridden for each component specified

estimate_mass()[source]¶: Generic method to estimate the mass of the component - assume mass is 0. This method should be overridden for each component specified

plot_coords(rotation=<Quantity(0, 'degree')>)[source]¶

xcg()[source]¶

xcp(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶

class rocketPy.components.Component(name='Component', mass=None, inertia=None)[source]¶

Bases: object

Base class for all components

Parameters

name (str) – Name of component. Defaults to ‘Component’.
mass (function or None or Quantity) – Mass of component. Defaults to None. If None: calls the self.estimate_mass() method to assign mass. If function: calls the function and assigns mass If Pint.Quantity: assigns mass directly.
inertia (function or None or Quantity) – Assigns inertia of the rocket, in (I_xx, I_yy, I_zz). Rest of the components are assumed to be 0. Defaults to None. If None: calls the self.estimate_inertia() method to assign inertia. If function: calls the function to assign the inertia. The function must return a tuple of (I_xx, I_yy, I_zz) If tuple of Pint.Quantity: assigns the inertia direction. The tuple must be (I_xx, I_yy, I_zz) with each being a Pint.Quantity of the right units.

Examples: Examples should be written in doctest format, and should illustrate how to use the function/class. >>>

estimate_mass[source]¶

Description of parameter estimate_mass.

Type: type

I_xx¶

Description of parameter I_xx.

Type: type

I_yy¶

Description of parameter I_yy.

Type: type

I_zz¶

Description of parameter I_zz.

Type: type

estimate_inertia[source]¶

Description of parameter estimate_inertia.

Type: type

x_ref¶

Description of parameter x_ref.

Type: type

y_ref¶

Description of parameter y_ref.

Type: type

z_ref¶

Description of parameter z_ref.

Type: type

A_ref¶

Description of parameter A_ref.

Type: type

name¶

mass¶

describe()[source]¶

estimate_inertia()[source]: Generic method to estimate the mass of the component - assume inertia is 0. This method should be overridden for each component specified

estimate_mass()[source]: Generic method to estimate the mass of the component - assume mass is 0. This method should be overridden for each component specified

plot(ax=None, rotation=<Quantity(0, 'degree')>, unit=<Unit('meter')>)[source]¶

Plots the component.

Parameters

ax (type) – Description of parameter ax. Defaults to None.
rotation (type) – Description of parameter rotation. Defaults to 0*ureg.degree.
unit (type) – Description of parameter unit. Defaults to ureg.m.

Returns

Description of returned object.

Return type

type

Examples: Examples should be written in doctest format, and should illustrate how to use the function/class. >>>

plot_coords()[source]¶

set_position(start_of=None, end_of=None, middle_of=None, after=None, offset=<Quantity(0, 'meter')>)[source]¶

Defines the x_ref of this component relative to other components.

Parameters

start_of (Component) – If not None, aligns self with other. Defaults to None.
end_of (Component) – If not None, aligns end of self with other. Defaults to None.
middle_of (Component) – If not None, aligns midpoints of self and other. Defaults to None.
after (Component) – If not None, aligns start of self to end of other. Defaults to None.
offset (Pint.Quantity) – Follows rules as above, but adds offset to self.x_ref. Defaults to 0*ureg.m.

Examples: Examples should be written in doctest format, and should illustrate how to use the function/class. >>>

xcg(*args)[source]¶

xcp(*args)[source]¶

ycg(*args)[source]¶

zcg(*args)[source]¶

class rocketPy.components.Cylinder(name='Internal Cylinder', mass=None, inertia=None, diameter=<Quantity(6, 'inch')>, length=<Quantity(6, 'inch')>, density=None)[source]¶

Bases: rocketPy.components.InternalComponent

estimate_inertia()[source]¶: Generic method to estimate the mass of the component - assume inertia is 0. This method should be overridden for each component specified

estimate_mass()[source]¶: Generic method to estimate the mass of the component - assume mass is 0. This method should be overridden for each component specified

class rocketPy.components.ExternalComponent(name='External Component', mass=None, inertia=None, A_ref=<Quantity(28.274333882308138, 'inch ** 2')>)[source]¶

Bases: rocketPy.components.Component

CN(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶

CNa(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶

class rocketPy.components.FinSet(name='Fins', mass=None, inertia=None, n=None, span=None, root_chord=None, tip_chord=None, mid_sweep=None, tube_dia=None, thickness=None, material=None)[source]¶

Bases: rocketPy.components.ExternalComponent

CNa(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶

estimate_inertia()[source]¶: Generic method to estimate the mass of the component - assume inertia is 0. This method should be overridden for each component specified

estimate_mass()[source]¶: Generic method to estimate the mass of the component - assume mass is 0. This method should be overridden for each component specified

leading_sweep()[source]¶: Return the leading edge sweep of the fins

plot_coords(rotation=<Quantity(0, 'radian')>)[source]¶

xcg()[source]¶

xcp(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶

class rocketPy.components.InternalComponent(name='Internal Component', mass=None, inertia=None)[source]¶

Bases: rocketPy.components.Component

CN(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶

class rocketPy.components.NoseCone(name='Nose Cone', mass=None, inertia=None, shape='Conical', diameter=None, length=None, fineness=None, wall_thickness=<Quantity(2, 'millimeter')>, material=None)[source]¶

Bases: rocketPy.components.ExternalComponent

CNa(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶

estimate_inertia()[source]¶: Generic method to estimate the mass of the component - assume inertia is 0. This method should be overridden for each component specified

estimate_mass()[source]¶: Method to estimate the mass of the nose cone

plot_coords(rotation=<Quantity(0, 'degree')>)[source]¶

xcg()[source]¶

xcp(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶

class rocketPy.components.Transition(name='Transition', mass=None, inertia=None, fore_dia=None, aft_dia=None, length=None, wall_thickness=<Quantity(2, 'millimeter')>, material=None)[source]¶

Bases: rocketPy.components.ExternalComponent

CNa(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶

estimate_inertia()[source]¶: Generic method to estimate the mass of the component - assume inertia is 0. This method should be overridden for each component specified

estimate_mass()[source]¶: Generic method to estimate the mass of the component - assume mass is 0. This method should be overridden for each component specified

plot_coords(rotation=<Quantity(0, 'degree')>)[source]¶

xcg()[source]¶

xcp(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶

rocketPy.materials module¶

Defines all the materials and their material properties. Base class Material allows for users to define a material, while some specific commonly used materials are predefined to help speed up the design process. Users should check that the right material properties are assumed for their parts.

class rocketPy.materials.Acrylic(name='Acrylic')[source]¶: Bases: rocketPy.materials.Material

class rocketPy.materials.Aluminium(name='Al-6061-T6')[source]¶

Bases: rocketPy.materials.Material

Defines a basic aluminium.

Parameters: name (str) – Description of parameter name. Defaults to ‘Al-6061-T6’.

Examples: Examples should be written in doctest format, and should illustrate how to use the function/class. >>>

density¶

Description of parameter density.

Type: Pint.Quantity

tensile_modulus¶

Description of parameter tensile_modulus.

Type: Pint.Quantity

tensile_strength¶

Description of parameter tensile_strength.

Type: Pint.Quantity

max_temp¶

Description of parameter max_temp.

Type: Pint.Quantity

class rocketPy.materials.Material(name)[source]¶

Bases: object

Base class for defining material properties

Parameters: name (str) – Name of material.

Examples: Examples should be written in doctest format, and should illustrate how to use the function/class. >>>

density¶

Material Density.

Type: Pint.Quantity

name¶

name

Type: str

describe()[source]¶

class rocketPy.materials.PLA(name='PLA')[source]¶: Bases: rocketPy.materials.Material

class rocketPy.materials.Phenolic(name='Phenolic')[source]¶: Bases: rocketPy.materials.Material

class rocketPy.materials.Plywood(name='Plywood')[source]¶: Bases: rocketPy.materials.Material

class rocketPy.materials.Polycarbonate(name='Polycarbonate')[source]¶: Bases: rocketPy.materials.Material

rocketPy.rocket module¶

Module to describe the rocket

class rocketPy.rocket.Rocket(name='Rocket')[source]¶

Bases: object

CA(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶: Compute the axial drag force from the normal force and the axial force

CD(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶: Calculate the drag force at some angle of attack, including compressibility

CD0(Re=1000000.0)[source]¶: Calcualte the zero angle-of-attack incompressible drag of the rocket. Generally uses DATCOM method (as specified by Box [1]) Reynolds number refers to the reynolds number by the length of the rocket.

CD0_b(Re=1000000.0)[source]¶: Calcualte the zero-angle of attack drag due to base drag

CD0_f(Re=1000000.0)[source]¶: Calcualte the zero-angle of attack drag due to the fins, including the effect of the interference

CD0_fb(Re=1000000.0)[source]¶: Calcualte the zero-angle of attack drag due to forebody of the rocket

CD_body_alpha(alpha=<Quantity(0, 'radian')>)[source]¶

CD_fin_alpha(alpha)[source]¶

CN(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶

CNa(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶

Cf(Re=1000000.0)[source]¶: Return the viscous friction coefficient at a Reynolds number

add(component)[source]¶

describe(describe_components=False)[source]¶

inertia_matrix(mass=None, with_inverse=False)[source]¶

inertia_xx()[source]¶

inertia_yy()[source]¶

inertia_zz()[source]¶

length()[source]¶

mass()[source]¶

plot(ax=None, unit=<Unit('meter')>, rotation=<Quantity(0, 'degree')>, plot_component_cp=True, plot_component_cg=True, alpha=<Quantity(0, 'degree')>, Re=1000000.0, Mach=0.3)[source]¶

plot_cg(ax=None, unit=<Unit('meter')>)[source]¶

plot_cp(ax=None, unit=<Unit('meter')>, alpha=<Quantity(0, 'degree')>, Re=1000000.0, Mach=0.3)[source]¶

set_boat_tail(component)[source]¶: Set the boat tail component

set_body_tube(component)[source]¶: Set the body tube of the rocket

set_fins(component)[source]¶: Set the fin set of the rocket

set_nose_cone(component)[source]¶: Set the nose cone of the rocket

static_margin(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3, mass=None)[source]¶

xcg(mass=None)[source]¶

xcp(alpha=<Quantity(0, 'radian')>, Re=1000000.0, Mach=0.3)[source]¶

rocketPy.util module¶

Utility functions for rocketPy

rocketPy.util.angle_between(va, vb)[source]¶: Return the angle between two column vectors using the dot product

rocketPy.util.mach_correction(Ma=0.0, method='default')[source]¶

Performs the Prandtl-Glauert compressibility correction, extended for supersonic region.

Parameters

Ma (dimensionless float) – Mach Number. Defaults to 0.0.
method (str) – Choose the correction method (‘default’ or ‘Cambridge’). Defaults to ‘default’.

Returns

Mach correction multiplier (float)

Return type

dimensionless float

Examples: Examples should be written in doctest format, and should illustrate how to use the function/class. >>> mach_correction(0.5) 1.1547005383792517 >> mach_correction(1.5) 0.8944271909999159

rocketPy.util.si(v)[source]¶

Utility function to convert a Pint Quantity into a float in SI units.

Parameters: v (Pint.Quantity or list/numpy.Array of Pint.Quantity) – quantity or list of quantities to convert.
Returns: magnitudes in SI units.
Return type: float or list of floats

Examples: Examples should be written in doctest format, and should illustrate how to use the function/class. >>> si(5.0*ureg.meter) 5.0 >> si(6.0*ureg.inch) 0.1524

rocketPy.util.unit_vector(v)[source]¶: Return a unit vector in the direction of v.

rocketPy.solution module¶

class rocketPy.solution.Solution(sol, stage)[source]¶

Bases: object

DOF()[source]¶

Returns the number of degrees of freedom in the state vector

Returns

length of state vector

Return type

int

__add__(other)[source]¶

Overloading the + operator to allow solutions to be ‘added’ together, essentially chaining them.

Parameters

other (Solution) –

Returns

Solution object with both objects inside

Return type

Solution

__init__(sol, stage)[source]¶

Wrapper for np.ODEresult to store extra information. Most importantly, allows multiple ODEresults to be chained together, with potential for storing extra information in them, and making it easy to access properties from each.

Parameters

sol (ODEresult or List of ODEresult) – The ODEresult objects to be stored

stage (int or list of int) – Corresponding stage counters

Returns

Solution object

Return type

Solution

__repr__()[source]¶

Display string

sol(time, error='raise')[source]¶

Returns the state at requested times. Assumes that scipy.integrate was called with dense_output=True and thus uses scipy’s interpolation method

Parameters

time (float or np.array) – Float time to request the solution for, or list/array of times that the state is requested for.

error ('raise' or numeric) – if the requested time is outside the interpolations capabilities, if error=’raise’, will raise a warning, else will return error in the state. Maintains the shape of the state vector.

Returns

state vector. If time is float, returns simple array of the right length. if time is a list of length n and state has length m, returns a shape of size (n x m).

Return type

np.array

t_max()[source]¶

Maximim time of all the solutions in this object. Computes a simple maximum, gaps are not accounted for.

Returns

maximum time

Return type

float

t_min()[source]¶

Minimum time of all the solutions in this object. Computes a simple minimum, gaps are not accounted for.

Returns

minimum time

Return type

float

rocketPy.simulation module¶

class rocketPy.simulation.Simulation(object)[source]¶

Bases: object

full_solve(t_span, y0, starting_stage, **kwargs)[source]¶

Solves every single possible outcome.

#todo (low): add probability weighting

Parameters

t_span ([float, float]) – Timespan for the solve

y0 (np.array) – Initial state vector

starting_stage (int) – Initial stage to start from

Returns

list of possible outcomes

Return type

list of rocketPy.Solution

nominal_solve(t_span, y0, starting_stage, **kwargs)[source]¶

Solves for a nominal flight

Parameters

t_span ([float, float]) – Timespan to simulate over

y0 (np.array) – Initial state

starting_stage (int) – which stage to start in

Returns

Solution object

Return type

rocketPy.Solution

solve(t_span, y0, stage, user_events=[], **kwargs)[source]¶

Thin wrapper for scipy.solve_ivp to handle stages and events more intuitively. Arguments generally follow scipy.solve_ivp. The dynamics are picked up from object.dynamics, and dense_output=True to allow for solutions to be queried later Solve method uses scipy default, but can be specified using kwargs

Parameters

t_span ([float, float]) – Simulation start and stop time.

y0 (np.array) – Initial state vector

stage (float) – stage number to use for the solve

user_events (list of functions) – each function is an event function. Defaults to [].

Returns

solution object with the stage stored

Return type

rocketPy.Solution

Module contents¶

Top-level package for rocketPy.