"""
Estimation of maximum center of gravity ratio
"""
# 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
from openmdao.core.explicitcomponent import ExplicitComponent
[docs]class ComputeMaxCGratio(ExplicitComponent):
# TODO: Document equations. Cite sources
""" Maximum center of gravity ratio estimation """
[docs] def setup(self):
self.add_input("data:weight:aircraft:empty:CG:MAC_position", val=np.nan)
self.add_input("data:weight:aircraft:load_case_1:CG:MAC_position", val=np.nan)
self.add_input("data:weight:aircraft:load_case_2:CG:MAC_position", val=np.nan)
self.add_input("data:weight:aircraft:load_case_3:CG:MAC_position", val=np.nan)
self.add_input("data:weight:aircraft:load_case_4:CG:MAC_position", val=np.nan)
self.add_input(
"settings:weight:aircraft:CG:aft:MAC_position:margin",
val=0.05,
desc="Added margin for getting most aft CG position, "
"as ratio of mean aerodynamic chord",
)
self.add_output("data:weight:aircraft:CG:aft:MAC_position")
[docs] def setup_partials(self):
self.declare_partials("*", "*", method="fd")
[docs] def compute(self, inputs, outputs):
outputs["data:weight:aircraft:CG:aft:MAC_position"] = inputs[
"settings:weight:aircraft:CG:aft:MAC_position:margin"
] + max(
inputs["data:weight:aircraft:empty:CG:MAC_position"],
inputs["data:weight:aircraft:load_case_1:CG:MAC_position"],
inputs["data:weight:aircraft:load_case_2:CG:MAC_position"],
inputs["data:weight:aircraft:load_case_3:CG:MAC_position"],
inputs["data:weight:aircraft:load_case_4:CG:MAC_position"],
)