"""
Python module for horizontal tail mean aerodynamic chord calculation, part of the horizontal
tail geometry.
"""
# This file is part of FAST-OAD_CS23 : A framework for rapid Overall Aircraft Design
# Copyright (C) 2025 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 ComputeHTMAC(om.ExplicitComponent):
# TODO: Document equations. Cite sources
"""
Horizontal tail mean aerodynamic chord estimation.
"""
# pylint: disable=missing-function-docstring
# Overriding OpenMDAO setup
[docs] def setup(self):
self.add_input("data:geometry:horizontal_tail:root:chord", val=np.nan, units="m")
self.add_input("data:geometry:horizontal_tail:tip:chord", val=np.nan, units="m")
self.add_input("data:geometry:horizontal_tail:sweep_25", val=np.nan, units="rad")
self.add_input("data:geometry:horizontal_tail:span", val=np.nan, units="m")
self.add_output("data:geometry:horizontal_tail:MAC:length", units="m")
self.add_output("data:geometry:horizontal_tail:MAC:at25percent:x:local", units="m")
self.add_output("data:geometry:horizontal_tail:MAC:y", units="m")
self.declare_partials(
"data:geometry:horizontal_tail:MAC:length",
["data:geometry:horizontal_tail:root:chord", "data:geometry:horizontal_tail:tip:chord"],
method="exact",
)
self.declare_partials(
"data:geometry:horizontal_tail:MAC:at25percent:x:local",
[
"data:geometry:horizontal_tail:root:chord",
"data:geometry:horizontal_tail:tip:chord",
"data:geometry:horizontal_tail:sweep_25",
"data:geometry:horizontal_tail:span",
],
method="exact",
)
self.declare_partials(
"data:geometry:horizontal_tail:MAC:y",
[
"data:geometry:horizontal_tail:root:chord",
"data:geometry:horizontal_tail:tip:chord",
"data:geometry:horizontal_tail:span",
],
method="exact",
)
# pylint: disable=missing-function-docstring, unused-argument
# Overriding OpenMDAO compute, not all arguments are used
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
root_chord = inputs["data:geometry:horizontal_tail:root:chord"]
tip_chord = inputs["data:geometry:horizontal_tail:tip:chord"]
sweep_25_ht = inputs["data:geometry:horizontal_tail:sweep_25"]
b_h = inputs["data:geometry:horizontal_tail:span"]
chord_sum = root_chord + tip_chord
mac_ht = (chord_sum**2.0 - root_chord * tip_chord) / (1.5 * chord_sum)
x0_ht = (
(root_chord * 0.5 + b_h * np.tan(sweep_25_ht) - tip_chord * 0.5)
* (chord_sum + tip_chord)
/ (6.0 * chord_sum)
)
y0_ht = b_h * (chord_sum + tip_chord) / (6.0 * chord_sum)
outputs["data:geometry:horizontal_tail:MAC:length"] = mac_ht
outputs["data:geometry:horizontal_tail:MAC:at25percent:x:local"] = x0_ht
outputs["data:geometry:horizontal_tail:MAC:y"] = y0_ht
# pylint: disable=missing-function-docstring, unused-argument
# Overriding OpenMDAO compute_partials, not all arguments are used
[docs] def compute_partials(self, inputs, partials, discrete_inputs=None):
root_chord = inputs["data:geometry:horizontal_tail:root:chord"]
tip_chord = inputs["data:geometry:horizontal_tail:tip:chord"]
sweep_25_ht = inputs["data:geometry:horizontal_tail:sweep_25"]
b_h = inputs["data:geometry:horizontal_tail:span"]
chord_sum = root_chord + tip_chord
partials[
"data:geometry:horizontal_tail:MAC:length", "data:geometry:horizontal_tail:root:chord"
] = (1.0 - (tip_chord / chord_sum) ** 2.0) / 1.5
partials[
"data:geometry:horizontal_tail:MAC:length", "data:geometry:horizontal_tail:tip:chord"
] = (1.0 - (root_chord / chord_sum) ** 2.0) / 1.5
partials[
"data:geometry:horizontal_tail:MAC:at25percent:x:local",
"data:geometry:horizontal_tail:root:chord",
] = (chord_sum**2.0 + 2.0 * tip_chord * (tip_chord - b_h * np.tan(sweep_25_ht))) / (
12.0 * chord_sum**2.0
)
partials[
"data:geometry:horizontal_tail:MAC:at25percent:x:local",
"data:geometry:horizontal_tail:tip:chord",
] = (root_chord * (root_chord + b_h * np.tan(sweep_25_ht)) - chord_sum**2.0) / (
6.0 * chord_sum**2.0
)
partials[
"data:geometry:horizontal_tail:MAC:at25percent:x:local",
"data:geometry:horizontal_tail:sweep_25",
] = b_h * (chord_sum + tip_chord) / (6.0 * chord_sum * np.cos(sweep_25_ht) ** 2.0)
partials[
"data:geometry:horizontal_tail:MAC:at25percent:x:local",
"data:geometry:horizontal_tail:span",
] = (chord_sum + tip_chord) * np.tan(sweep_25_ht) / (6.0 * chord_sum)
partials["data:geometry:horizontal_tail:MAC:y", "data:geometry:horizontal_tail:span"] = (
chord_sum + tip_chord
) / (6.0 * chord_sum)
partials[
"data:geometry:horizontal_tail:MAC:y", "data:geometry:horizontal_tail:root:chord"
] = -b_h * tip_chord / (6.0 * chord_sum**2.0)
partials[
"data:geometry:horizontal_tail:MAC:y", "data:geometry:horizontal_tail:tip:chord"
] = b_h * root_chord / (6.0 * chord_sum**2.0)