''' Title : Part 23 V-n Diagram Scope : This example computes and plots the V-n diagram for a Part-23 class aircraft Author : Matthew Clarke Date : Feb 18th, 2026 ''' # ---------------------------------------------------------------------------------------------------------------------- # IMPORT # ---------------------------------------------------------------------------------------------------------------------- import RCAIDE from RCAIDE.Framework.Core import Units from RCAIDE.Library.Methods.Powertrain.Propulsors.Internal_Combustion_Engine import design_internal_combustion_engine from RCAIDE.Library.Methods.Performance import generate_V_n_diagram from RCAIDE.Library.Plots import * # package imports import numpy as np import sys import os import numpy as np import matplotlib.pyplot as plt def main(): # Set up vehicle vehicle = vehicle_setup() # Set up vehicle configs configs = configs_setup(vehicle) # create analyses analyses = analyses_setup(configs) # Vn Diagram V_n_data = generate_V_n_diagram(analyses=analyses.cruise) plot_V_n_diagram(V_n_data, vehicle) return # ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------- # ############################################################################################################################################################################ # ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------- # ---------------------------------------------------------------------------------------------------------------------- # Build the Vehicle # ---------------------------------------------------------------------------------------------------------------------- def vehicle_setup(): # ------------------------------------------------------------------ # File Paths # ------------------------------------------------------------------ ospath = os.path.abspath(__file__) separator = os.path.sep local_path = os.path.dirname(ospath) + separator + '..' airfoil_file_path = local_path + separator + 'Airfoils_and_Polars' + separator polar_file_path = local_path + separator + 'Airfoils_and_Polars' + separator + 'Polars' + separator #------------------------------------------------------------------------------------------------------------------------------------ # ################################################# Vehicle-level Properties ######################################################## #------------------------------------------------------------------------------------------------------------------------------------ vehicle = RCAIDE.Vehicle() vehicle.tag = 'Cessna_172' vehicle.mass_properties.max_takeoff = 2550. * Units.pounds vehicle.mass_properties.takeoff = 2550. * Units.pounds vehicle.mass_properties.max_zero_fuel = 1680 * Units.pounds vehicle.mass_properties.max_fuel = 152.407 vehicle.mass_properties.max_payload = 910 * Units.pounds vehicle.mass_properties.cargo = 0. # envelope properties vehicle.flight_envelope.ultimate_load = 5.7 vehicle.flight_envelope.positive_limit_load = 3.8 vehicle.flight_envelope.design_range = 750 * Units.nmi vehicle.flight_envelope.design_dynamic_pressure = 2755 # max speed at 10 k feet vehicle.flight_envelope.design_mach_number = 0.18745866156304694 vehicle.flight_envelope.category = 'normal' vehicle.flight_envelope.FAR_part_number = '23' vehicle.flight_envelope.maximum_lift_coefficient = 3 vehicle.flight_envelope.minimum_lift_coefficient = -1.5 # basic parameters vehicle.reference_area = 174. * Units.feet**2 vehicle.number_of_passengers = 4 #------------------------------------------------------------------------------------------------------------------------------------ # ##################################################### Landing Gear ################################################################ #------------------------------------------------------------------------------------------------------------------------------------ main_gear = RCAIDE.Library.Components.Landing_Gear.Main_Landing_Gear() main_gear.tire_diameter = 6 * Units.inches main_gear.rim_diameter = 3 * Units.inches main_gear.tire_width = 6 * Units.inches main_gear.strut_length = 12 * Units.ft main_gear.wheels = 4 main_gear.number_of_gear_types_in_tandem = 1 main_gear.number_of_wheels_in_gear_type = 2 main_gear.fairing = True main_gear.xz_plane_symmetric = True main_gear.gear_extended = True vehicle.append_component(main_gear) nose_gear = RCAIDE.Library.Components.Landing_Gear.Nose_Landing_Gear() nose_gear.tire_diameter = 5 * Units.inches nose_gear.rim_diameter = 3 * Units.inches nose_gear.tire_width = 5 * Units.inches nose_gear.strut_length = 6.* Units.ft nose_gear.wheels = 2 nose_gear.fairing = True nose_gear.gear_extended = True nose_gear.number_of_gear_types_in_tandem = 1 nose_gear.number_of_wheels_in_gear_type = 2 vehicle.append_component(nose_gear) #------------------------------------------------------------------------------------------------------------------------------------ # ######################################################## Wings #################################################################### #------------------------------------------------------------------------------------------------------------------------------------ # ------------------------------------------------------------------ # Main Wing # ------------------------------------------------------------------ wing = RCAIDE.Library.Components.Wings.Main_Wing() wing.tag = 'main_wing' wing.sweeps.quarter_chord = 0.0 * Units.deg wing.thickness_to_chord = 0.12 wing.areas.reference = 174. * Units.feet**2 wing.spans.projected = 36. * Units.feet + 1. * Units.inches wing.chords.root = 66. * Units.inches wing.chords.tip = 45. * Units.inches wing.chords.mean_aerodynamic = 58. * Units.inches wing.taper = wing.chords.tip/wing.chords.root wing.aspect_ratio = wing.spans.projected**2. / wing.areas.reference wing.twists.root = 3.0 * Units.degrees wing.twists.tip = 1.5 * Units.degrees wing.origin = [[80.* Units.inches,0, 0.820]] wing.aerodynamic_center = [22.* Units.inches,0,0] wing.vertical = False wing.xz_plane_symmetric = True wing.dynamic_pressure_ratio = 1.0 # control surfaces ------------------------------------------- flap = RCAIDE.Library.Components.Wings.Control_Surfaces.Flap() flap.tag = 'flap' flap.span_fraction_start = 0.15 flap.span_fraction_end = 0.324 flap.deflection = 1.0 * Units.deg flap.chord_fraction = 0.19 wing.append_control_surface(flap) slat = RCAIDE.Library.Components.Wings.Control_Surfaces.Slat() slat.tag = 'slat' slat.span_fraction_start = 0.324 slat.span_fraction_end = 0.963 slat.deflection = 1.0 * Units.deg slat.chord_fraction = 0.1 wing.append_control_surface(slat) # add to vehicle vehicle.append_component(wing) # ------------------------------------------------------------------ # Horizontal Stabilizer # ------------------------------------------------------------------ wing = RCAIDE.Library.Components.Wings.Horizontal_Tail() wing.tag = 'horizontal_stabilizer' wing.sweeps.quarter_chord = 0.0 * Units.deg wing.thickness_to_chord = 0.12 wing.areas.reference = 5800. * Units.inches**2 wing.spans.projected = 136. * Units.inches wing.chords.root = 55. * Units.inches wing.chords.tip = 30. * Units.inches wing.chords.mean_aerodynamic = 43. * Units.inches wing.taper = wing.chords.tip/wing.chords.root wing.aspect_ratio = wing.spans.projected**2. / wing.areas.reference wing.twists.root = 0.0 * Units.degrees wing.twists.tip = 0.0 * Units.degrees wing.origin = [[246.* Units.inches,0,0]] wing.aerodynamic_center = [20.* Units.inches,0,0] wing.vertical = False wing.xz_plane_symmetric = True wing.dynamic_pressure_ratio = 0.9 wing_airfoil = RCAIDE.Library.Components.Airfoils.NACA_4_Series_Airfoil() wing.append_airfoil(wing_airfoil) elevator = RCAIDE.Library.Components.Wings.Control_Surfaces.Elevator() elevator.tag = 'elevator' elevator.span_fraction_start = 0.1 elevator.span_fraction_end = 0.9 elevator.deflection = 0.0 * Units.deg elevator.chord_fraction = 0.35 wing.append_control_surface(elevator) vehicle.append_component(wing) # ------------------------------------------------------------------ # Vertical Stabilizer # ------------------------------------------------------------------ wing = RCAIDE.Library.Components.Wings.Vertical_Tail() wing.tag = 'vertical_stabilizer' wing.sweeps.quarter_chord = 25. * Units.deg wing.thickness_to_chord = 0.12 wing.areas.reference = 3500. * Units.inches**2 wing.spans.projected = 73. * Units.inches wing.chords.root = 66. * Units.inches wing.chords.tip = 27. * Units.inches wing.chords.mean_aerodynamic = 48. * Units.inches wing.taper = wing.chords.tip/wing.chords.root wing.aspect_ratio = wing.spans.projected**2. / wing.areas.reference wing.twists.root = 0.0 * Units.degrees wing.twists.tip = 0.0 * Units.degrees wing.origin = [[237.* Units.inches,0,0]] wing.aerodynamic_center = [20.* Units.inches,0,0] wing.vertical = True wing.xz_plane_symmetric = False wing.t_tail = False wing.dynamic_pressure_ratio = 1.0 rudder = RCAIDE.Library.Components.Wings.Control_Surfaces.Rudder() rudder.tag = 'rudder' rudder.span_fraction_start = 0.1 rudder.span_fraction_end = 0.9 rudder.deflection = 0.0 * Units.deg rudder.chord_fraction = 0.4 wing.append_control_surface(rudder) # add to vehicle vehicle.append_component(wing) #------------------------------------------------------------------------------------------------------------------------------------ # ########################################################## Fuselage ############################################################### #------------------------------------------------------------------------------------------------------------------------------------ fuselage = RCAIDE.Library.Components.Fuselages.Fuselage() fuselage.differential_pressure = 8*Units.psi # Maximum differential pressure fuselage.width = 42. * Units.inches # Width of the fuselage fuselage.heights.maximum = 62. * Units.inches # Height of the fuselage fuselage.lengths.total = 326. * Units.inches # Length of the fuselage fuselage.lengths.tail = 161. * Units.inches fuselage.lengths.cabin = 105. * Units.inches fuselage.volume_properties.gross_volume = .4*fuselage.lengths.total*(np.pi/4.)*(fuselage.heights.maximum**2.) fuselage.areas.wetted = 30000. * Units.inches**2. fuselage.fineness.nose = 1.6 fuselage.fineness.tail = 2. fuselage.lengths.nose = 60. * Units.inches fuselage.heights.at_quarter_length = 62. * Units.inches fuselage.heights.at_three_quarters_length = 62. * Units.inches fuselage.heights.at_wing_root_quarter_chord = 23. * Units.inches fuselage.areas.front_projected = fuselage.width* fuselage.heights.maximum fuselage.effective_diameter = 50. * Units.inches cabin = RCAIDE.Library.Components.Fuselages.Cabins.Cabin() economy_class = RCAIDE.Library.Components.Fuselages.Cabins.Classes.Economy() cabin.origin = [[2, 0, 0]] economy_class.number_of_seats_abrest = 2 economy_class.number_of_rows = 2 economy_class.aisle_width = 0 economy_class.seat_arm_rest_width = 1 * Units.inches economy_class.number_of_seats = economy_class.number_of_rows * economy_class.number_of_seats_abrest cabin.append_cabin_class(economy_class) fuselage.append_cabin(cabin) # Segment segment = RCAIDE.Library.Components.Fuselages.Segments.Segment() segment.tag = 'segment_0' segment.percent_x_location = 0.0000 segment.percent_z_location = 0.0000 fuselage.segments.append(segment) # Segment segment = RCAIDE.Library.Components.Fuselages.Segments.Super_Ellipse_Segment() segment.tag = 'segment_1' segment.percent_x_location = 0.02077 segment.percent_z_location = 0.0 segment.height = 0.31619 segment.width = 0.33071 fuselage.segments.append(segment) # Segment segment = RCAIDE.Library.Components.Fuselages.Segments.Rounded_Rectangle_Segment() segment.tag = 'segment_2' segment.percent_x_location = 0.03852 segment.percent_z_location = -0.02000 segment.height = 0.73441 segment.width = 0.40654 fuselage.segments.append(segment) # Segment segment = RCAIDE.Library.Components.Fuselages.Segments.Rounded_Rectangle_Segment() segment.tag = 'segment_3' segment.percent_x_location = 0.16595 segment.percent_z_location = -0.01226 segment.height = 1.00366 segment.width = 0.90341 segment.radius = 0.29143 fuselage.segments.append(segment) # Segment segment = RCAIDE.Library.Components.Fuselages.Segments.Rounded_Rectangle_Segment() segment.tag = 'segment_4' segment.percent_x_location = 0.24391 segment.percent_z_location = 0.01016 segment.height = 1.52704 segment.width = 1.06680 segment.radius = 0.43714 fuselage.segments.append(segment) # Segment segment = RCAIDE.Library.Components.Fuselages.Segments.Rounded_Rectangle_Segment() segment.tag = 'segment_5' segment.percent_x_location = 0.43388 segment.percent_z_location = 0.0132 segment.height = 1.50557 segment.width = 1.06680 segment.radius = 0.4007 fuselage.segments.append(segment) # Segment segment = RCAIDE.Library.Components.Fuselages.Segments.Rounded_Rectangle_Segment() segment.tag = 'segment_6' segment.percent_x_location = 0.53122 segment.percent_z_location = -0.00895 segment.height = 0.97386 segment.width = 0.73776 segment.radius = 0.29143 fuselage.segments.append(segment) # Segment segment = RCAIDE.Library.Components.Fuselages.Segments.Ellipse_Segment() segment.tag = 'segment_7' segment.percent_x_location = 0.74233 segment.percent_z_location = 0 segment.height = 0.55067 segment.width = 0.4517 fuselage.segments.append(segment) # Segment segment = RCAIDE.Library.Components.Fuselages.Segments.Segment() segment.tag = 'segment_9' segment.percent_x_location = 0.98310 segment.percent_z_location = 0 segment.height = 0.17226 segment.width = 0.18068 fuselage.segments.append(segment) # Segment segment = RCAIDE.Library.Components.Fuselages.Segments.Segment() segment.tag = 'segment_9' segment.percent_x_location = 1.0 segment.percent_z_location = 0.00189 fuselage.segments.append(segment) # add to vehicle vehicle.append_component(fuselage) #------------------------------------------------------------------------------------------------------------------------------------ # ########################################################## Energy Network ######################################################### #------------------------------------------------------------------------------------------------------------------------------------ #initialize the fuel network net = RCAIDE.Framework.Networks.Fuel() # add the network to the vehicle vehicle.append_energy_network(net) #------------------------------------------------------------------------------------------------------------------------------------ # Bus #------------------------------------------------------------------------------------------------------------------------------------ fuel_line = RCAIDE.Library.Components.Powertrain.Distributors.Fuel_Line() #------------------------------------------------------------------------------------------------------------------------------------ # Fuel Tank & Fuel #------------------------------------------------------------------------------------------------------------------------------------ fuel_tank = RCAIDE.Library.Components.Powertrain.Sources.Fuel_Tanks.Fuel_Tank() fuel_tank.origin = vehicle.wings.main_wing.origin fuel_tank.fuel = RCAIDE.Library.Attributes.Propellants.Aviation_Gasoline() fuel_tank.fuel.mass_properties.mass = 319 *Units.lbs fuel_tank.mass_properties.center_of_gravity = wing.mass_properties.center_of_gravity fuel_line.fuel_tanks.append(fuel_tank) #------------------------------------------------------------------------------------------------------------------------------------ # Propulsor #------------------------------------------------------------------------------------------------------------------------------------ ice_prop = RCAIDE.Library.Components.Powertrain.Propulsors.Internal_Combustion_Engine() # Engine engine = RCAIDE.Library.Components.Powertrain.Converters.Engine() engine.sea_level_power = 180. * Units.horsepower engine.flat_rate_altitude = 0.0 engine.rated_speed = 2700. * Units.rpm engine.power_specific_fuel_consumption = 0.52 * Units['lb/hp/hr'] ice_prop.engine = engine # Propeller prop = RCAIDE.Library.Components.Powertrain.Converters.Propeller() prop.tag = 'propeller' prop.number_of_blades = 2.0 prop.tip_radius = 76./2. * Units.inches prop.hub_radius = 8. * Units.inches prop.cruise.design_freestream_velocity = 119. * Units.knots prop.cruise.design_angular_velocity = 2650. * Units.rpm prop.cruise.design_lift_coefficient = 0.8 prop.cruise.design_altitude = 12000. * Units.feet prop.cruise.design_power = .64 * 180. * Units.horsepower prop.variable_pitch = True airfoil = RCAIDE.Library.Components.Airfoils.Airfoil() airfoil.tag = 'NACA_4412' airfoil.coordinate_file = airfoil_file_path + 'NACA_4412.txt' # absolute path airfoil.polar_files =[ polar_file_path + 'NACA_4412_polar_Re_50000.txt', polar_file_path + 'NACA_4412_polar_Re_100000.txt', polar_file_path + 'NACA_4412_polar_Re_200000.txt', polar_file_path + 'NACA_4412_polar_Re_500000.txt', polar_file_path + 'NACA_4412_polar_Re_1000000.txt'] prop.append_airfoil(airfoil) prop.airfoil_polar_stations = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0] ice_prop.propeller = prop # design propeller ICE design_internal_combustion_engine(ice_prop) net.propulsors.append(ice_prop) #------------------------------------------------------------------------------------------------------------------------------------ # Assign propulsors to fuel line to network fuel_line.assigned_propulsors = [[ice_prop.tag]] #------------------------------------------------------------------------------------------------------------------------------------ # Append fuel line to fuel line to network net.fuel_lines.append(fuel_line) #------------------------------------------------------------------------------------------------------------------------------------ # Avionics #------------------------------------------------------------------------------------------------------------------------------------ Wuav = 2. * Units.lbs avionics = RCAIDE.Library.Components.Powertrain.Systems.Avionics() avionics.mass_properties.uninstalled = Wuav vehicle.avionics = avionics #------------------------------------------------------------------------------------------------------------------------------------ # Vehicle Definition Complete #------------------------------------------------------------------------------------------------------------------------------------ return vehicle def configs_setup(vehicle): # ------------------------------------------------------------------ # Initialize Configurations # ------------------------------------------------------------------ configs = RCAIDE.Library.Components.Configs.Config.Container() base_config = RCAIDE.Library.Components.Configs.Config(vehicle) base_config.tag = 'base' configs.append(base_config) # ------------------------------------------------------------------ # Cruise Configuration # ------------------------------------------------------------------ config = RCAIDE.Library.Components.Configs.Config(base_config) config.tag = 'cruise' configs.append(config) # ------------------------------------------------------------------ # Takeoff Configuration # ------------------------------------------------------------------ config = RCAIDE.Library.Components.Configs.Config(base_config) config.tag = 'takeoff' config.wings['main_wing'].control_surfaces.flap.deflection = 20. * Units.deg config.maximum_lift_coefficient = 2. configs.append(config) # ------------------------------------------------------------------ # Landing Configuration # ------------------------------------------------------------------ config = RCAIDE.Library.Components.Configs.Config(base_config) config.tag = 'landing' config.wings['main_wing'].control_surfaces.flap.deflection = 20. * Units.deg config.maximum_lift_coefficient = 2. configs.append(config) # done! return configs def analyses_setup(configs): analyses = RCAIDE.Framework.Analyses.Analysis.Container() # build a base analysis for each config for tag,config in configs.items(): analysis = base_analysis(config) analyses[tag] = analysis return analyses def base_analysis(vehicle): # ------------------------------------------------------------------ # Initialize the Analyses # ------------------------------------------------------------------ analyses = RCAIDE.Framework.Analyses.Vehicle() analyses.vehicle = vehicle # Geometry geometry = RCAIDE.Framework.Analyses.Geometry.Geometry() analyses.append(geometry) # ------------------------------------------------------------------ # Weights weights = RCAIDE.Framework.Analyses.Weights.Conventional_General_Aviation() analyses.append(weights) # ------------------------------------------------------------------ # Aerodynamics Analysis aerodynamics = RCAIDE.Framework.Analyses.Aerodynamics.Vortex_Lattice_Method() analyses.append(aerodynamics) # ------------------------------------------------------------------ # Energy energy = RCAIDE.Framework.Analyses.Energy.Energy() analyses.append(energy) # ------------------------------------------------------------------ # Planet Analysis planet = RCAIDE.Framework.Analyses.Planets.Earth() analyses.append(planet) # ------------------------------------------------------------------ # Atmosphere Analysis atmosphere = RCAIDE.Framework.Analyses.Atmospheric.US_Standard_1976() analyses.append(atmosphere) # done! return analyses # ---------------------------------------------------------------------- # Call Main # ---------------------------------------------------------------------- if __name__ == '__main__': main() plt.show()