"""
Estimation of yawing moment due to sideslip
"""
# 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: This belongs more to aerodynamics than geometry
[docs]class ComputeCnBetaFuselage(ExplicitComponent):
# TODO: Document equations. Cite sources
""" Yawing moment due to sideslip estimation """
[docs] def setup(self):
self.add_input("data:geometry:fuselage:maximum_width", val=np.nan, units="m")
self.add_input("data:geometry:fuselage:maximum_height", val=np.nan, units="m")
self.add_input("data:geometry:fuselage:length", val=np.nan, units="m")
self.add_input("data:geometry:fuselage:front_length", val=np.nan, units="m")
self.add_input("data:geometry:fuselage:rear_length", val=np.nan, units="m")
self.add_input("data:geometry:wing:area", val=np.nan, units="m**2")
self.add_input("data:geometry:wing:span", val=np.nan, units="m")
self.add_output("data:aerodynamics:fuselage:cruise:CnBeta")
[docs] def setup_partials(self):
self.declare_partials("data:aerodynamics:fuselage:cruise:CnBeta", "*", method="fd")
[docs] def compute(self, inputs, outputs):
fus_length = inputs["data:geometry:fuselage:length"]
lav = inputs["data:geometry:fuselage:front_length"]
lar = inputs["data:geometry:fuselage:rear_length"]
width_max = inputs["data:geometry:fuselage:maximum_width"]
height_max = inputs["data:geometry:fuselage:maximum_height"]
wing_area = inputs["data:geometry:wing:area"]
span = inputs["data:geometry:wing:span"]
l_f = math.sqrt(width_max * height_max)
l_cyc = fus_length - lav - lar
# estimation of fuselage volume
volume_fus = math.pi * l_f ** 2 / 4 * (0.7 * lav + 0.5 * lar + l_cyc)
# equation from raymer book eqn. 16.47
cn_beta_fus = -1.3 * volume_fus / wing_area / span * (l_f / width_max)
outputs["data:aerodynamics:fuselage:cruise:CnBeta"] = cn_beta_fus