"""
Estimation of main landing gear center of gravity
"""
# 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 UpdateMLG(om.ExplicitComponent):
# TODO: Document equations. Cite sources
""" Main landing gear center of gravity estimation """
[docs] def setup(self):
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_input("data:weight:aircraft:CG:aft:MAC_position", val=np.nan)
self.add_input("data:weight:airframe:landing_gear:front:CG:x", units="m")
self.add_input("settings:weight:airframe:landing_gear:front:weight_ratio", val=0.08)
self.add_output("data:weight:airframe:landing_gear:main:CG:x", units="m")
[docs] def setup_partials(self):
self.declare_partials("data:weight:airframe:landing_gear:main:CG:x", "*", method="fd")
[docs] def compute(self, inputs, outputs):
l0_wing = inputs["data:geometry:wing:MAC:length"]
fa_length = inputs["data:geometry:wing:MAC:at25percent:x"]
cg_ratio = inputs["data:weight:aircraft:CG:aft:MAC_position"]
cg_a52 = inputs["data:weight:airframe:landing_gear:front:CG:x"]
front_lg_weight_ratio = inputs["settings:weight:airframe:landing_gear:front:weight_ratio"]
x_cg = fa_length - 0.25 * l0_wing + cg_ratio * l0_wing
cg_a51 = (x_cg - front_lg_weight_ratio * cg_a52) / (1 - front_lg_weight_ratio)
outputs["data:weight:airframe:landing_gear:main:CG:x"] = cg_a51