"""
Estimation of landing gear weight
"""
# 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 LandingGearWeight(om.ExplicitComponent):
"""
Weight estimation for landing gears
Based on formulas in :cite:`supaero:2014`, mass contribution A5
"""
[docs] def setup(self):
self.add_input("data:weight:aircraft:MTOW", val=np.nan, units="kg")
self.add_input("tuning:weight:airframe:landing_gear:mass:k", val=1.0)
self.add_input("tuning:weight:airframe:landing_gear:mass:offset", val=0.0, units="kg")
self.add_output("data:weight:airframe:landing_gear:main:mass", units="kg")
self.add_output("data:weight:airframe:landing_gear:front:mass", units="kg")
[docs] def setup_partials(self):
self.declare_partials("*", "*", method="fd")
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
mtow = inputs["data:weight:aircraft:MTOW"]
k_a5 = inputs["tuning:weight:airframe:landing_gear:mass:k"]
offset_a5 = inputs["tuning:weight:airframe:landing_gear:mass:offset"]
temp_a51 = 18.1 + 0.131 * mtow ** 0.75 + 0.019 * mtow + 2.23e-5 * mtow ** 1.5
temp_a52 = 9.1 + 0.082 * mtow ** 0.75 + 2.97e-6 * mtow ** 1.5
a51 = k_a5 * temp_a51 + offset_a5
a52 = k_a5 * temp_a52 + offset_a5
outputs["data:weight:airframe:landing_gear:main:mass"] = a51
outputs["data:weight:airframe:landing_gear:front:mass"] = a52