"""
Estimation of engine 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
from openmdao.core.explicitcomponent import ExplicitComponent
# TODO: this is also provided by class RubberEngine
[docs]class EngineWeight(ExplicitComponent):
"""
Engine weight estimation
Uses model described in :cite:`roux:2005`, p.74
"""
[docs] def setup(self):
self.add_input("data:propulsion:MTO_thrust", val=np.nan, units="N")
self.add_input("data:geometry:propulsion:engine:count", val=np.nan)
self.add_input("tuning:weight:propulsion:engine:mass:k", val=1.0)
self.add_input("tuning:weight:propulsion:engine:mass:offset", val=0.0, units="kg")
self.add_output("data:weight:propulsion:engine: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):
sea_level_thrust = inputs["data:propulsion:MTO_thrust"]
n_engines = inputs["data:geometry:propulsion:engine:count"]
k_b1 = inputs["tuning:weight:propulsion:engine:mass:k"]
offset_b1 = inputs["tuning:weight:propulsion:engine:mass:offset"]
if sea_level_thrust < 80000:
temp_b1 = 22.2e-3 * sea_level_thrust
else:
temp_b1 = 14.1e-3 * sea_level_thrust + 648
temp_b1 *= n_engines * 1.55
outputs["data:weight:propulsion:engine:mass"] = k_b1 * temp_b1 + offset_b1