aerosandbox.library.field_lengths ================================= .. py:module:: aerosandbox.library.field_lengths Attributes ---------- .. autoapisummary:: aerosandbox.library.field_lengths.results Functions --------- .. autoapisummary:: aerosandbox.library.field_lengths.field_length_analysis_torenbeek aerosandbox.library.field_lengths.field_length_analysis Module Contents --------------- .. py:function:: field_length_analysis_torenbeek(design_mass_TOGW, thrust_at_liftoff, lift_over_drag_climb, CL_max, s_ref, n_engines, atmosphere = None, CD_zero_lift = 0.03, obstacle_height = 35 * u.foot, friction_coefficient = 0.02, V_obstacle_over_V_stall = 1.3, minimum_V_liftoff_over_V_stall = 1.2, V_approach_over_V_stall = 1.3, maximum_braking_deceleration_g = 0.37, inertia_time = 4.5, approach_angle_deg = 3) Performs a field length analysis on an aircraft, returning a dictionary of field length parameters. Citations: * "Torenbeek": Egbert Torenbeek, "Synthesis of Subsonic Airplane Design", 1976. (Generally, section 5.4.5: Takeoff) :param design_mass_TOGW: The takeoff gross weight of the entire aircraft [kg]. :param thrust_at_liftoff: The thrust of the aircraft at the moment of liftoff [N]. :param lift_over_drag_climb: The lift-to-drag ratio of the aircraft during the climb phase of takeoff [dimensionless]. :param CL_max: The maximum lift coefficient of the aircraft [dimensionless]. Assumes any lift-augmentation devices ( :param e.g.: :param slats: :param flaps) are deployed.: :param s_ref: The reference area of the aircraft [m^2]. :param atmosphere: The atmosphere object to use for the analysis. Defaults to sea level. :param n_engines: The number of engines on the aircraft. Used during balanced field length calculation, :param which involves a single-engine-failure assumption.: :param CD_zero_lift: The zero-lift drag coefficient of the aircraft [dimensionless]. :param obstacle_height: The height of the obstacle clearance [m]. .. note:: * FAR 23 requires a 50 foot obstacle clearance height. * FAR 25 requires a 35 foot obstacle clearance height. :param friction_coefficient: The coefficient of friction between the wheels and the runway. * 0.02 is a good value for a dry concrete runway. * 0.045 is a good value for short grass. :param V_obstacle_over_V_stall: The ratio of the airspeed while flying over the obstacle to the stall airspeed. :param minimum_V_liftoff_over_V_stall: The minimum-allowable ratio of the liftoff airspeed to the stall airspeed. :param V_approach_over_V_stall: The ratio of the approach airspeed to the stall airspeed. :param maximum_braking_deceleration_g: The maximum deceleration of the aircraft during braking [G]. This is used when calculating the "brake" portion of the "accelerate-brake" balanced field length, as well as the braking during normal landing. * Standard brakes are around 0.37 G on dry concrete. * Advanced brakes with optimum brake pressure control, lift dumpers, and nosewheel braking can be as high as 0.5 G on dry concrete. :param inertia_time: The time it takes for the pilot and aircraft to collectively react to an engine failure during :param takeoff [seconds]. This is collectively the sum of: * The pilot's reaction time * The time it takes the other engines to spool down, in the event of a rejected takeoff and deceleration on the ground. :returns: * "takeoff_ground_roll_distance": The distance the aircraft will roll on the ground during a normal takeoff before liftoff [meters]. * "takeoff_airborne_distance": The distance the aircraft will travel in the air during a normal takeoff [ meters]. This is after liftoff, but before the aircraft has reached the obstacle clearance height. * "takeoff_total_distance": The total field length required during a normal takeoff [meters]. This includes both the ground roll itself, as well as the airborne distance before the obstacle clearance height is reached. * "balanced_field_length": The field length required for takeoff and obstacle clearance when one engine fails at "decision speed" [meters]. Decision speed is the speed during the ground roll at which, if an engine fails, the aircraft can either continue the takeoff or brake to a complete stop in the same total distance. * "landing_airborne_distance": The distance the aircraft will travel in the air during a normal landing before touchdown [meters]. Note that a normal landing involves passing the runway threshold at the specified obstacle clearance height. * "landing_ground_roll_distance": The distance the aircraft will roll on the ground after touchdown during a normal landing [meters]. * "landing_total_distance": The total field length required during a normal landing [meters]. This includes both the airborne distance beyond the threshold that is required for obstacle clearance, as well as the ground roll distance after touchdown. * "V_stall": The stall speed of the aircraft at its takeoff gross weight [m/s]. * "V_liftoff": The airspeed at the moment of liftoff during a normal takeoff [m/s]. * "V_obstacle": The airspeed when the aircraft reaches the obstacle clearance height during a normal takeoff [m/s]. * "V_approach": The airspeed when the aircraft reaches the runway threshold during a normal landing. * "V_touchdown": The airspeed when the aircraft touches down during a normal landing. * "flight_path_angle_climb": The flight path angle during a normal takeoff at the point when the airplane reaches the obstacle clearance height [radians]. * "flight_path_angle_climb_one_engine_out": The flight path angle during a critical-engine-out takeoff at the point when the airplane reaches the obstacle clearance height [radians]. If this number is negative, engine failure results in inability to climb. :rtype: A dictionary of field length parameters, including .. py:function:: field_length_analysis(design_mass_TOGW, thrust_at_liftoff, lift_over_drag_climb, CL_max, s_ref, n_engines, V_engine_failure_balanced_field_length, atmosphere = None, CD_zero_lift = 0.03, obstacle_height = 35 * u.foot, friction_coefficient = 0.02, minimum_V_liftoff_over_V_stall = 1.2, maximum_braking_deceleration_g = 0.37, inertia_time = 2, approach_angle_deg = 3) .. py:data:: results