ENH: Adds GenericMotor.load_from_eng_file() method

CHANGELOG.md

@@ -32,17 +32,19 @@ Attention: The newest changes should be on top -->
 
 ### Added
 
+- ENH: Adds GenericMotor.load_from_eng_file() method [#676](https://github.com/RocketPy-Team/RocketPy/pull/676)
+- ENH: Introducing local sensitivity analysis [#575](https://github.com/RocketPy-Team/RocketPy/pull/575)
 - ENH: Add STFT function to Function class [#620](https://github.com/RocketPy-Team/RocketPy/pull/620) 
 - ENH: Rocket Axis Definition [#635](https://github.com/RocketPy-Team/RocketPy/pull/635)
 
 ### Changed
 
-- DOC: Fix documentation dependencies [#651](https://github.com/RocketPy-Team/RocketPy/pull/651)
-- DOC: Fix documentation warnings [#645](https://github.com/RocketPy-Team/RocketPy/pull/645)
 - DOC: New Environment class docs pages [#644](https://github.com/RocketPy-Team/RocketPy/pull/644)
 
 ### Fixed
 
+- DOC: Fix documentation dependencies [#651](https://github.com/RocketPy-Team/RocketPy/pull/651)
+- DOC: Fix documentation warnings [#645](https://github.com/RocketPy-Team/RocketPy/pull/645)
 - BUG: Rotational EOMs Not Relative To CDM [#674](https://github.com/RocketPy-Team/RocketPy/pull/674)
 - BUG: Pressure ISA Extrapolation as "linear" [#675](https://github.com/RocketPy-Team/RocketPy/pull/675)
 - BUG: fix the Frequency Response plot of Flight class [#653](https://github.com/RocketPy-Team/RocketPy/pull/653)

docs/user/motors/genericmotor.rst

@@ -0,0 +1,108 @@
+.. _genericmotor:
+
+GenericMotor Class Usage
+========================
+
+Here we explore different features of the GenericMotor class.
+
+Class that represents a simple motor defined mainly by its thrust curve.
+There is no distinction between the propellant types (e.g. Solid, Liquid).
+This class is meant for rough estimations of the motor performance,
+therefore for more accurate results, use the ``SolidMotor``, ``HybridMotor``
+or ``LiquidMotor`` classes.
+
+Creating a Generic Motor
+------------------------
+
+To define a generic motor, we will need a few information about our motor:
+
+- The thrust source file, which is a file containing the thrust curve of the motor. \
+  This file can be a .eng file, a .rse file, or a .csv file. See more details in \
+  :doc:`Thrust Source Details </user/motors/thrust>`
+- A few physical parameters, which the most important are:
+    - The burn time of the motor.
+    - The combustion chamber radius;
+    - The combustion chamber height;
+    - The combustion chamber position;
+    - The propellant initial mass;
+    - The nozzle radius;
+    - The motor dry mass.
+
+The usage of the GenericMotor class is very similar to the other motor classes.
+See more details in the
+:doc:`SolidMotor Class Usage </user/motors/solidmotor>`,
+:doc:`LiquidMotor Class Usage </user/motors/liquidmotor>`, and
+:doc:`HybridMotor Class Usage </user/motors/hybridmotor>` pages.
+
+
+.. jupyter-execute::
+
+    from rocketpy.motors import GenericMotor
+
+    # Define the motor parameters
+    motor = GenericMotor(
+      thrust_source = "../data/motors/Cesaroni_M1670.eng",
+      burn_time = 3.9,
+      chamber_radius = 33 / 100,
+      chamber_height = 600 / 1000,
+      chamber_position = 0,
+      propellant_initial_mass = 2.5,
+      nozzle_radius = 33 / 1000,
+      dry_mass = 1.815,
+      center_of_dry_mass_position = 0,
+      dry_inertia = (0.125, 0.125, 0.002),
+      nozzle_position = 0,
+      reshape_thrust_curve = False,
+      interpolation_method = "linear",
+      coordinate_system_orientation = "nozzle_to_combustion_chamber",
+    )
+
+    # Print the motor information
+    motor.info()
+
+.. note::
+
+    The GenericMotor is a simplified model of a rocket motor. If you need more \
+    accurate results, use the ``SolidMotor``, ``HybridMotor`` or ``LiquidMotor`` classes.
+
+
+The ``load_from_eng_file`` method
+---------------------------------
+
+The ``GenericMotor`` class has a method called ``load_from_eng_file`` that allows
+the user to build a GenericMotor object by providing just the path to an .eng file.
+
+The parameters available in the method are the same as the ones used in the
+constructor of the GenericMotor class. But the method will automatically read 
+the .eng file and extract the required information if the user does not 
+provide it. In this case, the following assumptions about the most 
+relevant parameters are made:
+
+- The ``chamber_radius`` is assumed to be the same as the motor diameter in the .eng file;
+- The ``chamber_height`` is assumed to be the same as the motor length in the .eng file;
+- The ``chamber_position`` is assumed to be 0;
+- The ``propellant_initial_mass`` is assumed to be the same as the propellant mass in the .eng file;
+- The ``nozzle_radius`` is assumed to be 85% of the ``chamber_radius``;
+- The ``dry_mass`` is assumed to be the total mass minus the propellant mass in the .eng file;
+
+As an example, we can demonstrate:
+
+.. jupyter-execute::
+
+    from rocketpy.motors import GenericMotor
+
+
+    # Load the motor from an .eng file
+    motor = GenericMotor.load_from_eng_file("../data/motors/Cesaroni_M1670.eng")
+
+    # Print the motor information
+    motor.info()
+
+Although the ``load_from_eng_file`` method is very useful, it is important to
+note that the user can still provide the parameters manually if needed.
+
+.. tip::
+
+  The ``load_from_eng_file`` method is a very useful tool for simulating motors \
+  when the user does not have all the information required to build a ``SolidMotor`` yet.
+

docs/user/motors/motors.rst

@@ -24,6 +24,12 @@ Motors Usage
     :caption: Liquid Motors
 
     Liquid Motor Usage <liquidmotor.rst>
+
+.. toctree::
+    :maxdepth: 3
+    :caption: Generic Motors
+
+    Generic Motor Usage <genericmotor.rst>
 
 .. toctree::
     :maxdepth: 3

rocketpy/motors/hybrid_motor.py

@@ -302,16 +302,16 @@ class Function. Thrust units are Newtons.
         None
         """
         super().__init__(
-            thrust_source,
-            dry_mass,
-            dry_inertia,
-            nozzle_radius,
-            center_of_dry_mass_position,
-            nozzle_position,
-            burn_time,
-            reshape_thrust_curve,
-            interpolation_method,
-            coordinate_system_orientation,
+            thrust_source=thrust_source,
+            dry_inertia=dry_inertia,
+            nozzle_radius=nozzle_radius,
+            center_of_dry_mass_position=center_of_dry_mass_position,
+            dry_mass=dry_mass,
+            nozzle_position=nozzle_position,
+            burn_time=burn_time,
+            reshape_thrust_curve=reshape_thrust_curve,
+            interpolation_method=interpolation_method,
+            coordinate_system_orientation=coordinate_system_orientation,
         )
         self.liquid = LiquidMotor(
             thrust_source,

rocketpy/motors/liquid_motor.py

@@ -230,16 +230,16 @@ class Function. Thrust units are Newtons.
             "nozzle_to_combustion_chamber".
         """
         super().__init__(
-            thrust_source,
-            dry_mass,
-            dry_inertia,
-            nozzle_radius,
-            center_of_dry_mass_position,
-            nozzle_position,
-            burn_time,
-            reshape_thrust_curve,
-            interpolation_method,
-            coordinate_system_orientation,
+            thrust_source=thrust_source,
+            dry_inertia=dry_inertia,
+            nozzle_radius=nozzle_radius,
+            center_of_dry_mass_position=center_of_dry_mass_position,
+            dry_mass=dry_mass,
+            nozzle_position=nozzle_position,
+            burn_time=burn_time,
+            reshape_thrust_curve=reshape_thrust_curve,
+            interpolation_method=interpolation_method,
+            coordinate_system_orientation=coordinate_system_orientation,
         )
 
         self.positioned_tanks = []