"""
Estimation of horizontal tail mean aerodynamic chords
"""
# 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 math
import numpy as np
from openmdao.core.explicitcomponent import ExplicitComponent
# TODO: it would be good to have a function to compute MAC for HT, VT and WING
[docs]class ComputeHTMAC(ExplicitComponent):
# TODO: Document equations. Cite sources
""" Horizontal tail mean aerodynamic chord estimation """
[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="deg")
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")
[docs] def setup_partials(self):
self.declare_partials(
"data:geometry:horizontal_tail:MAC:length",
["data:geometry:horizontal_tail:root:chord", "data:geometry:horizontal_tail:tip:chord"],
method="fd",
)
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="fd",
)
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="fd",
)
[docs] def compute(self, inputs, outputs):
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"]
tmp = (
root_chord * 0.25 + b_h / 2 * math.tan(sweep_25_ht / 180.0 * math.pi) - tip_chord * 0.25
)
mac_ht = (
(root_chord ** 2 + root_chord * tip_chord + tip_chord ** 2)
/ (tip_chord + root_chord)
* 2
/ 3
)
x0_ht = (tmp * (root_chord + 2 * tip_chord)) / (3 * (root_chord + tip_chord))
y0_ht = (b_h * (0.5 * root_chord + tip_chord)) / (3 * (root_chord + tip_chord))
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