"""
Python module for engine weight calculation, part of the propulsion system mass computation.
"""
# This file is part of FAST-OAD_CS23 : A framework for rapid Overall Aircraft Design
# Copyright (C) 2025 ONERA & ISAE-SUPAERO
# FAST is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
import fastoad.api as oad
import openmdao.api as om
# noinspection PyProtectedMember
from fastoad.module_management._bundle_loader import BundleLoader
from .constants import (
SERVICE_INSTALLED_ENGINE_MASS,
SUBMODEL_INSTALLED_ENGINE_MASS_LEGACY,
SUBMODEL_INSTALLED_ENGINE_MASS_RAYMER,
)
oad.RegisterSubmodel.active_models[SERVICE_INSTALLED_ENGINE_MASS] = (
SUBMODEL_INSTALLED_ENGINE_MASS_LEGACY
)
[docs]@oad.RegisterSubmodel(SERVICE_INSTALLED_ENGINE_MASS, SUBMODEL_INSTALLED_ENGINE_MASS_LEGACY)
class ComputeEngineWeight(om.ExplicitComponent):
"""
Engine weight estimation calling wrapper
Based on a statistical analysis. See :cite:`raymer:2012`, Table 15.2.
"""
def __init__(self, **kwargs):
super().__init__(**kwargs)
self._engine_wrapper = None
# pylint: disable=missing-function-docstring
# Overriding OpenMDAO initialize
[docs] def initialize(self):
self.options.declare("propulsion_id", default="", types=str)
# pylint: disable=missing-function-docstring
# Overriding OpenMDAO setup
[docs] def setup(self):
self._engine_wrapper = BundleLoader().instantiate_component(self.options["propulsion_id"])
self._engine_wrapper.setup(self)
self.add_input("settings:weight:propulsion:engine:k_factor", val=1.0)
self.add_output("data:weight:propulsion:engine:mass", units="lb")
self.declare_partials(of="*", wrt="*", method="fd")
# Overwrites the derivatives because we know the exact value
self.declare_partials(
of="*", wrt="settings:weight:propulsion:engine:k_factor", method="exact"
)
# pylint: disable=missing-function-docstring, unused-argument
# Overriding OpenMDAO compute, not all arguments are used
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
propulsion_model = self._engine_wrapper.get_model(inputs)
# This should give the UNINSTALLED weight
uninstalled_engine_weight = propulsion_model.compute_weight()
k_b1 = inputs["settings:weight:propulsion:engine:k_factor"]
b_1 = 1.4 * uninstalled_engine_weight
outputs["data:weight:propulsion:engine:mass"] = b_1 * k_b1
# pylint: disable=missing-function-docstring, unused-argument
# Overriding OpenMDAO compute_partials, not all arguments are used
[docs] def compute_partials(self, inputs, partials, discrete_inputs=None):
propulsion_model = self._engine_wrapper.get_model(inputs)
# This should give the UNINSTALLED weight
uninstalled_engine_weight = propulsion_model.compute_weight()
b_1 = 1.4 * uninstalled_engine_weight
partials[
"data:weight:propulsion:engine:mass", "settings:weight:propulsion:engine:k_factor"
] = b_1
[docs]@oad.RegisterSubmodel(SERVICE_INSTALLED_ENGINE_MASS, SUBMODEL_INSTALLED_ENGINE_MASS_RAYMER)
class ComputeEngineWeightRaymer(om.ExplicitComponent):
"""
Engine weight estimation calling wrapper
Based on a statistical analysis. See :cite:`raymer:2012` Formula 15.52, can also be found in
:cite:`roskampart5:1985` USAF method.
"""
def __init__(self, **kwargs):
super().__init__(**kwargs)
self._engine_wrapper = None
# pylint: disable=missing-function-docstring
# Overriding OpenMDAO initialize
[docs] def initialize(self):
self.options.declare("propulsion_id", default="", types=str)
# pylint: disable=missing-function-docstring
# Overriding OpenMDAO setup
[docs] def setup(self):
self._engine_wrapper = BundleLoader().instantiate_component(self.options["propulsion_id"])
self._engine_wrapper.setup(self)
self.add_input("settings:weight:propulsion:engine:k_factor", val=1.0)
self.add_output("data:weight:propulsion:engine:mass", units="lb")
self.declare_partials(of="*", wrt="*", method="fd")
# Overwrites the derivatives because we know the exact value
self.declare_partials(
of="*", wrt="settings:weight:propulsion:engine:k_factor", method="exact"
)
# pylint: disable=missing-function-docstring, unused-argument
# Overriding OpenMDAO compute, not all arguments are used
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
propulsion_model = self._engine_wrapper.get_model(inputs)
k_b1 = inputs["settings:weight:propulsion:engine:k_factor"]
# This should give the UNINSTALLED weight in lbs !
uninstalled_engine_weight = propulsion_model.compute_weight()
b_1 = 2.575 * uninstalled_engine_weight**0.922
outputs["data:weight:propulsion:engine:mass"] = b_1 * k_b1
# pylint: disable=missing-function-docstring, unused-argument
# Overriding OpenMDAO compute_partials, not all arguments are used
[docs] def compute_partials(self, inputs, partials, discrete_inputs=None):
propulsion_model = self._engine_wrapper.get_model(inputs)
# This should give the UNINSTALLED weight in lbs !
uninstalled_engine_weight = propulsion_model.compute_weight()
b_1 = 2.575 * uninstalled_engine_weight**0.922
partials[
"data:weight:propulsion:engine:mass", "settings:weight:propulsion:engine:k_factor"
] = b_1