"""
Estimation of center of gravity ratio with aft
"""
# This file is part of FAST-OAD : A framework for rapid Overall Aircraft Design
# Copyright (C) 2021 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 numpy as np
import openmdao.api as om
[docs]class ComputeCGRatioAft(om.Group):
[docs] def setup(self):
self.add_subsystem("cg_all", ComputeCG(), promotes=["*"])
self.add_subsystem("cg_ratio", CGRatio(), promotes=["*"])
[docs]class ComputeCG(om.ExplicitComponent):
[docs] def initialize(self):
self.options.declare(
"cg_names",
default=[
"data:weight:airframe:wing:CG:x",
"data:weight:airframe:fuselage:CG:x",
"data:weight:airframe:horizontal_tail:CG:x",
"data:weight:airframe:vertical_tail:CG:x",
"data:weight:airframe:flight_controls:CG:x",
"data:weight:airframe:landing_gear:main:CG:x",
"data:weight:airframe:landing_gear:front:CG:x",
"data:weight:airframe:pylon:CG:x",
"data:weight:airframe:paint:CG:x",
"data:weight:propulsion:engine:CG:x",
"data:weight:propulsion:fuel_lines:CG:x",
"data:weight:propulsion:unconsumables:CG:x",
"data:weight:systems:power:auxiliary_power_unit:CG:x",
"data:weight:systems:power:electric_systems:CG:x",
"data:weight:systems:power:hydraulic_systems:CG:x",
"data:weight:systems:life_support:insulation:CG:x",
"data:weight:systems:life_support:air_conditioning:CG:x",
"data:weight:systems:life_support:de-icing:CG:x",
"data:weight:systems:life_support:cabin_lighting:CG:x",
"data:weight:systems:life_support:seats_crew_accommodation:CG:x",
"data:weight:systems:life_support:oxygen:CG:x",
"data:weight:systems:life_support:safety_equipment:CG:x",
"data:weight:systems:navigation:CG:x",
"data:weight:systems:transmission:CG:x",
"data:weight:systems:operational:radar:CG:x",
"data:weight:systems:operational:cargo_hold:CG:x",
"data:weight:systems:flight_kit:CG:x",
"data:weight:furniture:passenger_seats:CG:x",
"data:weight:furniture:food_water:CG:x",
"data:weight:furniture:security_kit:CG:x",
"data:weight:furniture:toilets:CG:x",
],
)
self.options.declare(
"mass_names",
[
"data:weight:airframe:wing:mass",
"data:weight:airframe:fuselage:mass",
"data:weight:airframe:horizontal_tail:mass",
"data:weight:airframe:vertical_tail:mass",
"data:weight:airframe:flight_controls:mass",
"data:weight:airframe:landing_gear:main:mass",
"data:weight:airframe:landing_gear:front:mass",
"data:weight:airframe:pylon:mass",
"data:weight:airframe:paint:mass",
"data:weight:propulsion:engine:mass",
"data:weight:propulsion:fuel_lines:mass",
"data:weight:propulsion:unconsumables:mass",
"data:weight:systems:power:auxiliary_power_unit:mass",
"data:weight:systems:power:electric_systems:mass",
"data:weight:systems:power:hydraulic_systems:mass",
"data:weight:systems:life_support:insulation:mass",
"data:weight:systems:life_support:air_conditioning:mass",
"data:weight:systems:life_support:de-icing:mass",
"data:weight:systems:life_support:cabin_lighting:mass",
"data:weight:systems:life_support:seats_crew_accommodation:mass",
"data:weight:systems:life_support:oxygen:mass",
"data:weight:systems:life_support:safety_equipment:mass",
"data:weight:systems:navigation:mass",
"data:weight:systems:transmission:mass",
"data:weight:systems:operational:radar:mass",
"data:weight:systems:operational:cargo_hold:mass",
"data:weight:systems:flight_kit:mass",
"data:weight:furniture:passenger_seats:mass",
"data:weight:furniture:food_water:mass",
"data:weight:furniture:security_kit:mass",
"data:weight:furniture:toilets:mass",
],
)
[docs] def setup(self):
for cg_name in self.options["cg_names"]:
self.add_input(cg_name, val=np.nan, units="m")
for mass_name in self.options["mass_names"]:
self.add_input(mass_name, val=np.nan, units="kg")
self.add_output("data:weight:aircraft_empty:mass", units="kg")
self.add_output("data:weight:aircraft_empty:CG:x", units="m")
[docs] def setup_partials(self):
self.declare_partials("data:weight:aircraft_empty:mass", "*", method="fd")
self.declare_partials("data:weight:aircraft_empty:CG:x", "*", method="fd")
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
cgs = [inputs[cg_name][0] for cg_name in self.options["cg_names"]]
masses = [inputs[mass_name][0] for mass_name in self.options["mass_names"]]
weight_moment = np.dot(cgs, masses)
outputs["data:weight:aircraft_empty:mass"] = np.sum(masses)
outputs["data:weight:aircraft_empty:CG:x"] = (
weight_moment / outputs["data:weight:aircraft_empty:mass"]
)
[docs]class CGRatio(om.ExplicitComponent):
[docs] def setup(self):
self.add_input("data:weight:aircraft_empty:CG:x", val=np.nan, units="m")
self.add_input("data:geometry:wing:MAC:length", val=np.nan, units="m")
self.add_input("data:geometry:wing:MAC:at25percent:x", val=np.nan, units="m")
self.add_output("data:weight:aircraft:empty:CG:MAC_position")
[docs] def setup_partials(self):
self.declare_partials("*", "*", method="fd")
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
x_cg_all = inputs["data:weight:aircraft_empty:CG:x"]
wing_position = inputs["data:geometry:wing:MAC:at25percent:x"]
mac = inputs["data:geometry:wing:MAC:length"]
outputs["data:weight:aircraft:empty:CG:MAC_position"] = (
x_cg_all - wing_position + 0.25 * mac
) / mac