"""
Estimation of static margin
"""
# This file is part of FAST : A framework for rapid Overall Aircraft Design
# Copyright (C) 2020 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 ComputeStaticMargin(om.ExplicitComponent):
"""
Computation of static margin i.e. difference between CG ratio and neutral
point.
"""
[docs] def initialize(self):
self.options.declare("target", types=float, allow_none=True, default=None)
[docs] def setup(self):
self.add_input("data:weight:aircraft:CG:aft:MAC_position", val=np.nan)
self.add_input("data:aerodynamics:cruise:neutral_point:x", val=np.nan)
self.add_output("data:handling_qualities:static_margin")
self.declare_partials("*", "*", method="fd")
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
cg_ratio = inputs["data:weight:aircraft:CG:aft:MAC_position"]
ac_ratio = inputs["data:aerodynamics:cruise:neutral_point:x"]
outputs["data:handling_qualities:static_margin"] = ac_ratio - cg_ratio