"""
Estimation of empennage 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 EmpennageWeight(om.ExplicitComponent):
"""
Weight estimation for tail planes
Based on formulas in :cite:`supaero:2014`, mass contribution A3
"""
[docs] def setup(self):
self.add_input("data:geometry:has_T_tail", val=np.nan)
self.add_input("data:geometry:horizontal_tail:area", val=np.nan, units="m**2")
self.add_input("data:geometry:vertical_tail:area", val=np.nan, units="m**2")
self.add_input("data:geometry:propulsion:layout", val=np.nan)
self.add_input("tuning:weight:airframe:horizontal_tail:mass:k", val=1.0)
self.add_input("tuning:weight:airframe:horizontal_tail:mass:offset", val=0.0, units="kg")
self.add_input("tuning:weight:airframe:vertical_tail:mass:k", val=1.0)
self.add_input("tuning:weight:airframe:vertical_tail:mass:offset", val=0.0, units="kg")
self.add_output("data:weight:airframe:horizontal_tail:mass", units="kg")
self.add_output("data:weight:airframe:vertical_tail:mass", units="kg")
[docs] def setup_partials(self):
self.declare_partials("*", "*", method="fd")
# pylint: disable=too-many-locals
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
ht_area = inputs["data:geometry:horizontal_tail:area"]
vt_area = inputs["data:geometry:vertical_tail:area"]
k_a31 = inputs["tuning:weight:airframe:horizontal_tail:mass:k"]
offset_a31 = inputs["tuning:weight:airframe:horizontal_tail:mass:offset"]
k_a32 = inputs["tuning:weight:airframe:vertical_tail:mass:k"]
offset_a32 = inputs["tuning:weight:airframe:vertical_tail:mass:offset"]
propulsion_layout = np.round(inputs["data:geometry:propulsion:layout"])
tail_type = np.round(inputs["data:geometry:has_T_tail"])
k_tail = 1.3 if tail_type == 1 else 1.0
# Mass of the horizontal tail plane
temp_a31 = ht_area * (14.4 + 0.155 * ht_area) * k_tail
outputs["data:weight:airframe:horizontal_tail:mass"] = k_a31 * temp_a31 + offset_a31
# Mass of the vertical tail plane
k_engine = 1 if propulsion_layout == 1.0 else 1.5
temp_a32 = vt_area * (15.45 + 0.202 * vt_area) * k_engine * k_tail
outputs["data:weight:airframe:vertical_tail:mass"] = k_a32 * temp_a32 + offset_a32