"""
Estimation of center of gravity ratio with aft.
"""
# This file is part of FAST-OAD_CS23 : A framework for rapid Overall Aircraft Design
# Copyright (C) 2022 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 numpy as np
import openmdao.api as om
from ..cg_components.constants import (
SUBMODEL_WING_CG,
SUBMODEL_FUSELAGE_CG,
SUBMODEL_TAIL_CG,
SUBMODEL_FLIGHT_CONTROLS_CG,
SUBMODEL_LANDING_GEAR_CG,
SUBMODEL_PROPULSION_CG,
SUBMODEL_POWER_SYSTEMS_CG,
SUBMODEL_LIFE_SUPPORT_SYSTEMS_CG,
SUBMODEL_NAVIGATION_SYSTEMS_CG,
SUBMODEL_RECORDING_SYSTEMS_CG,
SUBMODEL_SEATS_CG,
SUBMODEL_AIRCRAFT_X_CG,
SUBMODEL_AIRCRAFT_X_CG_RATIO,
SUBMODEL_AIRCRAFT_Z_CG,
)
[docs]@oad.RegisterSubmodel(
SUBMODEL_AIRCRAFT_X_CG_RATIO, "fastga.submodel.weight.cg.aircraft_empty.x_ratio.legacy"
)
class ComputeCGRatioAircraftEmpty(om.Group):
[docs] def setup(self):
self.add_subsystem(
"wing_cg", oad.RegisterSubmodel.get_submodel(SUBMODEL_WING_CG), promotes=["*"]
)
self.add_subsystem(
"fuselage_cg", oad.RegisterSubmodel.get_submodel(SUBMODEL_FUSELAGE_CG), promotes=["*"]
)
self.add_subsystem(
"tail_cg", oad.RegisterSubmodel.get_submodel(SUBMODEL_TAIL_CG), promotes=["*"]
)
self.add_subsystem(
"flight_control_cg",
oad.RegisterSubmodel.get_submodel(SUBMODEL_FLIGHT_CONTROLS_CG),
promotes=["*"],
)
self.add_subsystem(
"landing_gear_cg",
oad.RegisterSubmodel.get_submodel(SUBMODEL_LANDING_GEAR_CG),
promotes=["*"],
)
self.add_subsystem(
"propulsion_cg",
oad.RegisterSubmodel.get_submodel(SUBMODEL_PROPULSION_CG),
promotes=["*"],
)
self.add_subsystem(
"power_systems_cg",
oad.RegisterSubmodel.get_submodel(SUBMODEL_POWER_SYSTEMS_CG),
promotes=["*"],
)
self.add_subsystem(
"life_support_cg",
oad.RegisterSubmodel.get_submodel(SUBMODEL_LIFE_SUPPORT_SYSTEMS_CG),
promotes=["*"],
)
self.add_subsystem(
"navigation_systems_cg",
oad.RegisterSubmodel.get_submodel(SUBMODEL_NAVIGATION_SYSTEMS_CG),
promotes=["*"],
)
self.add_subsystem(
"recording_systems_cg",
oad.RegisterSubmodel.get_submodel(SUBMODEL_RECORDING_SYSTEMS_CG),
promotes=["*"],
)
self.add_subsystem(
"passenger_seats_cg",
oad.RegisterSubmodel.get_submodel(SUBMODEL_SEATS_CG),
promotes=["*"],
)
self.add_subsystem(
"x_cg", oad.RegisterSubmodel.get_submodel(SUBMODEL_AIRCRAFT_X_CG), promotes=["*"]
)
self.add_subsystem(
"z_cg", oad.RegisterSubmodel.get_submodel(SUBMODEL_AIRCRAFT_Z_CG), promotes=["*"]
)
self.add_subsystem("cg_ratio", CGRatio(), promotes=["*"])
[docs]@oad.RegisterSubmodel(SUBMODEL_AIRCRAFT_X_CG, "fastga.submodel.weight.cg.aircraft_empty.x.legacy")
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:propulsion:engine:CG:x",
"data:weight:propulsion:fuel_lines:CG:x",
"data:weight:systems:power:electric_systems:CG:x",
"data:weight:systems:power:hydraulic_systems:CG:x",
"data:weight:systems:life_support:air_conditioning:CG:x",
"data:weight:systems:avionics:CG:x",
"data:weight:systems:recording:CG:x",
"data:weight:furniture:passenger_seats: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:propulsion:engine:mass",
"data:weight:propulsion:fuel_lines:mass",
"data:weight:systems:power:electric_systems:mass",
"data:weight:systems:power:hydraulic_systems:mass",
"data:weight:systems:life_support:air_conditioning:mass",
"data:weight:systems:avionics:mass",
"data:weight:systems:recording:mass",
"data:weight:furniture:passenger_seats: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")
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)
x_cg_empty_aircraft = weight_moment / outputs["data:weight:aircraft_empty:mass"]
outputs["data:weight:aircraft_empty:CG:x"] = x_cg_empty_aircraft
[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 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
[docs]@oad.RegisterSubmodel(SUBMODEL_AIRCRAFT_Z_CG, "fastga.submodel.weight.cg.aircraft_empty.z.legacy")
class ComputeZCG(om.ExplicitComponent):
[docs] def initialize(self):
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:propulsion:engine:mass",
"data:weight:propulsion:fuel_lines:mass",
"data:weight:systems:power:electric_systems:mass",
"data:weight:systems:power:hydraulic_systems:mass",
"data:weight:systems:life_support:air_conditioning:mass",
"data:weight:systems:avionics:mass",
"data:weight:furniture:passenger_seats:mass",
],
)
[docs] def setup(self):
for mass_name in self.options["mass_names"]:
self.add_input(mass_name, val=np.nan, units="kg")
self.add_input("data:geometry:fuselage:maximum_height", val=np.nan, units="m")
self.add_input("data:geometry:propeller:diameter", val=np.nan, units="m")
self.add_input("data:geometry:landing_gear:height", val=np.nan, units="m")
self.add_input("data:geometry:horizontal_tail:z:from_wingMAC25", val=np.nan, units="m")
self.add_input("data:geometry:vertical_tail:span", val=np.nan, units="m")
self.add_input("data:geometry:wing:MAC:length", val=np.nan, units="m")
self.add_input("data:geometry:wing:thickness_ratio", val=np.nan)
self.add_output("data:weight:aircraft_empty:CG:z", units="m")
self.add_output("data:weight:propulsion:engine:CG:z", units="m")
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
masses = [inputs[mass_name][0] for mass_name in self.options["mass_names"]]
height_max = inputs["data:geometry:fuselage:maximum_height"][0]
prop_dia = inputs["data:geometry:propeller:diameter"][0]
lg_height = inputs["data:geometry:landing_gear:height"][0]
ht_height = inputs["data:geometry:horizontal_tail:z:from_wingMAC25"][0]
vt_span = inputs["data:geometry:vertical_tail:span"][0]
l0_wing = inputs["data:geometry:wing:MAC:length"][0]
thickness_ratio = inputs["data:geometry:wing:thickness_ratio"][0]
# TODO : For now we assume low wings only, change later
cg_wing = lg_height + thickness_ratio * l0_wing / 2.0
cg_fuselage = lg_height + height_max / 2.0
cg_horizontal_tail = cg_wing + ht_height
cg_vertical_tail = cg_fuselage + vt_span / 2.0
# TODO : To be changed depending we want or not the case where LG are retractable
cg_landing_gear = lg_height / 2.0
# CS 23 gives a minimum ground clearance of 18 cm for nose wheel landing gear, but TB20,
# SR22, BE76 all use a 23 cm clearance as recommended for tail wheel landing gear
cg_engine = 0.23 + prop_dia / 2.0
cg_fuel_lines = (cg_engine + cg_wing) / 2.0
cgs = np.array(
[
cg_wing,
cg_fuselage,
cg_horizontal_tail,
cg_vertical_tail,
cg_fuselage,
cg_landing_gear,
cg_landing_gear,
cg_engine,
cg_fuel_lines,
cg_fuselage,
cg_fuselage,
cg_fuselage,
cg_fuselage,
cg_fuselage,
]
)
weight_moment = np.dot(cgs, masses)
z_cg_empty_aircraft = weight_moment / np.sum(masses)
outputs["data:weight:aircraft_empty:CG:z"] = z_cg_empty_aircraft
outputs["data:weight:propulsion:engine:CG:z"] = cg_engine