"""Class for very simple transition in some flight phases."""
# 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/>.
from copy import deepcopy
from dataclasses import dataclass
from typing import List, Tuple
import pandas as pd
from fastoad.model_base import FlightPoint
from fastoad.model_base.propulsion import IPropulsion
from fastoad.models.performances.mission.polar import Polar
from fastoad.models.performances.mission.segments.base import FlightSegment
[docs]@dataclass
class DummyTransitionSegment(FlightSegment, mission_file_keyword="transition"):
"""
Computes a transient flight part in a very quick and dummy way.
:meth:`compute_from` will return only 2 or 3 flight points.
The second flight point is the end of transition and its mass is the start mass
multiplied by :attr:`mass_ratio`. Other parameters are equal to those provided in
:attr:`~fastoad.models.performances.mission.segments.base.FlightSegment.target`.
If :attr:`reserve_mass_ratio` is non-zero, a third flight point, with parameters equal
to flight_point(2), except for mass where:
mass(2) - reserve_mass_ratio * mass(3) = mass(3).
In different words, mass(3) would be the Zero Fuel Weight (ZFW) and reserve can be
expressed as a percentage of ZFW.
"""
#: The ratio (aircraft mass at END of segment)/(aircraft mass at START of segment)
mass_ratio: float = 1.0
#: The ratio (fuel mass)/(aircraft mass at END of segment) that will be consumed at end
#: of segment.
reserve_mass_ratio: float = 0.0
#: Unused
propulsion: IPropulsion = None
#: Unused
reference_area: float = 1.0
#: Unused
polar: Polar = None
[docs] def compute_from(self, start: FlightPoint) -> pd.DataFrame:
self.complete_flight_point(start)
end = deepcopy(start)
end.mass = start.mass * self.mass_ratio
end.altitude = self.target.altitude
end.ground_distance = start.ground_distance + self.target.ground_distance
end.mach = self.target.mach
end.true_airspeed = self.target.true_airspeed
end.equivalent_airspeed = self.target.equivalent_airspeed
end.name = self.name
self.complete_flight_point(end)
flight_points = [start, end]
if self.reserve_mass_ratio > 0.0:
reserve = deepcopy(end)
reserve.mass = end.mass / (1.0 + self.reserve_mass_ratio)
flight_points.append(reserve)
return pd.DataFrame(flight_points)
def _get_gamma_and_acceleration(self, mass, drag, thrust) -> Tuple[float, float]:
return 0.0, 0.0
# As we overloaded self.compute_from(), next abstract method are not used.
# We just need to implement them for Python to be happy.
def _get_distance_to_target(self, flight_points: List[FlightPoint]) -> float:
pass
def _compute_propulsion(self, flight_point: FlightPoint):
pass