aerosandbox.library.costs#

Module Contents#

Functions#

modified_DAPCA_IV_production_cost_analysis(...[, ...])

Computes the cost of an aircraft in present-day dollars, using the Modified DAPCA IV cost model.

electric_aircraft_direct_operating_cost_analysis(...)

Estimates the overall operating cost of an electric aircraft. Includes both direct and indirect operating costs.

Attributes#

res

aerosandbox.library.costs.modified_DAPCA_IV_production_cost_analysis(design_empty_weight, design_maximum_airspeed, n_airplanes_produced, n_engines_per_aircraft, cost_per_engine, cost_avionics_per_airplane, n_pax, cpi_relative_to_2012_dollars=1.275, n_flight_test_aircraft=4, is_cargo_airplane=False, primary_structure_material='aluminum', per_passenger_cost_model='general_aviation', engineering_wrap_rate_2012_dollars=115.0, tooling_wrap_rate_2012_dollars=118.0, quality_control_wrap_rate_2012_dollars=108.0, manufacturing_wrap_rate_2012_dollars=98.0)[source]#

Computes the cost of an aircraft in present-day dollars, using the Modified DAPCA IV cost model.

Be sure to adjust cpi_relative_to_2012_dollars to the current values in order to accurately model inflation.

The DAPCA IV cost model is a statistical regression of historical aircraft cost data. It provides reasonable results for most classes of aircraft, including transports, fighters, bombers, and even GA and UAV aircraft with suitable adjustments.

It was created by the RAND Corporation.

The Modified DAPCA IV cost model is a modification of the DAPCA IV cost model that includes additional cost estimates for engine cost (as the original DAPCA model assumes that this is known).

See Raymer, Aircraft Design: A Conceptual Approach, 5th Edition, Section 18.4.2 pg. 711 for more information.

Parameters:

  • design_empty_weight (float) – The design empty weight of the entire aircraft, in kg.

  • design_maximum_airspeed (float) – The design maximum airspeed of the aircraft, in m/s.

  • n_airplanes_produced (int) – The number of airplanes to be produced.

  • n_engines_per_aircraft (int) – The number of engines per aircraft.

  • cost_per_engine (float) – The cost of each engine, in present-day dollars.

  • cost_avionics_per_airplane (float) – The cost of avionics per airplane, in present-day dollars.

  • n_pax (int) – The number of passengers.

  • cpi_relative_to_2012_dollars (float) – The consumer price index at the present day divided by the consumer price index

  • 2012 (in) –

    To quickly find this, use data from the St. Louis Federal Reserve. Below is the CPI, normalized to 2012. https://fred.stlouisfed.org/graph/?g=10PU0

    For example, in 2022, one would use 1.275.

  • seasonally-adjusted. –

    To quickly find this, use data from the St. Louis Federal Reserve. Below is the CPI, normalized to 2012. https://fred.stlouisfed.org/graph/?g=10PU0

    For example, in 2022, one would use 1.275.

  • n_flight_test_aircraft (int) – The number of flight test aircraft. Typically 2 to 6.

  • is_cargo_airplane (bool) – Whether the airplane is a cargo airplane. If so, the quality control cost is lower.

  • primary_structure_material (str) – The primary structure material. Options are: - “aluminum” - “carbon_fiber” - “fiberglass” - “steel” - “titanium”

  • per_passenger_cost_model (str) – The per-passenger cost model. Options are: - “general_aviation”: General aviation aircraft, such as Cessna 172s. - “jet_transport”: Jet transport aircraft, such as Boeing 737s. - “regional_transport”: Regional transport aircraft, such as Embraer E175s.

  • engineering_wrap_rate_2012_dollars (float) – The engineering wrap rate in 2012 dollars.

  • tooling_wrap_rate_2012_dollars (float) – The tooling wrap rate in 2012 dollars.

  • quality_control_wrap_rate_2012_dollars (float) – The quality control wrap rate in 2012 dollars.

  • manufacturing_wrap_rate_2012_dollars (float) – The manufacturing wrap rate in 2012 dollars.

Returns:

A dictionary of costs required to produce all n_airplanes_produced airplanes, in present-day dollars.

Keys and values are as follows:

  • ”engineering_labor”: Engineering labor cost.

  • ”tooling_labor”: Tooling labor cost.

  • ”manufacturing_labor”: Manufacturing labor cost.

  • ”quality_control_labor”: Quality control labor cost.

  • ”development_support”: Development support cost. From Raymer: “Includes fabrication of mockups, iron-bird subsystem

simulators, structural test articles, and other test articles.”

  • ”flight_test”: Flight test cost. From Raymer: “Includes all costs incurred to demonstrate airworthiness

for civil certification or Mil-Spec compliance except for the costs of the flight-test aircraft themselves. Costs for the flight-test aircraft are included in the total production-run cost estimation. Includes planning, instrumentation, flight operations, data reduction, and engineering and manufacturing support of flight testing.”

  • ”manufacturing_materials”: Manufacturing materials cost. From Raymer: “Includes all raw materials and

purchased hardware and equipment.”

  • ”engines”: Engine cost.

  • ”avionics”: Avionics cost.

  • ”total”: Total cost. (Sum of all other costs above.)

Return type:

Dict[str, float]

aerosandbox.library.costs.electric_aircraft_direct_operating_cost_analysis(production_cost_per_airframe, nominal_cruise_airspeed, nominal_mission_range, battery_capacity, num_passengers_nominal, num_crew=1, battery_fraction_used_on_nominal_mission=0.8, typical_passenger_utilization=0.8, flight_hours_per_year=1200, airframe_lifetime_years=20, airframe_eol_resale_value_fraction=0.4, battery_cost_per_kWh_capacity=500.0, battery_cycle_life=1500, real_interest_rate=0.04, electricity_cost_per_kWh=0.145, annual_expenses_per_crew=100000 * 1.5, ascent_time=0.2 * u.hour, descent_time=0.2 * u.hour)[source]#

Estimates the overall operating cost of an electric aircraft. Includes both direct and indirect operating costs.

Here, direct operating costs (DOC) are taken to include the following costs:

  • Airframe depreciation

  • Airframe financing

  • Insurance

  • Maintenance

  • Battery replacement

  • Energy costs (here, electricity)

  • Cockpit and cabin crew costs

  • Airport landing, terminal, and handling fees

Any costs that are not included here are considered indirect costs. These indirect costs would include, but are not limited to: advertisement, administrative costs, depreciation of non-airframe assets, and taxes.

Airframe maintenance costs are estimated from:

Moore, et al., “Unlocking Low-Cost Regional Air Mobility through…”, AIAA Aviation 2023.

Airport fees estimated for the Phoenix-Mesa Gateway Airport, due to public availability of the fee schedule: https://www.gatewayairport.com/documents/documentlibrary/wgaa%20organizational%20documents/airport%20rates%20charges%20-%20effective%20march%201,%202017.pdf

Parameters:

  • production_cost_per_airframe (float) – The cost to produce a single airframe, in present-day dollars. May be estimated using the modified_DAPCA_IV_production_cost_analysis() function.

  • nominal_cruise_airspeed (float) – The nominal cruise airspeed of the aircraft, in m/s.

  • nominal_mission_range (float) – The nominal mission range of the aircraft, in meters.

  • battery_capacity (float) – The total capacity of the battery, in Joules.

  • num_passengers_nominal (int) – The number of passengers that the aircraft is designed to carry.

  • num_crew (int) – The number of crew members required to operate the aircraft.

  • battery_fraction_used_on_nominal_mission (float) – The fraction of the battery’s capacity that is used on the nominal mission.

  • typical_passenger_utilization (float) – The fraction of the aircraft’s passenger capacity that is typically utilized.

  • flight_hours_per_year (float) – The number of flight hours per year that the aircraft is expected to fly.

  • airframe_lifetime_years (float) – The number of years that the airframe is expected to last. After this time, the airframe is assumed to be sold at some lower reasle value.

  • airframe_eol_resale_value_fraction (float) – The expect resale value of the airframe at the end of its lifetime, expressed as a fraction of the airframe’s production cost.

  • battery_cost_per_kWh_capacity (float) – The replacement cost of the battery pack, per kWh of capacity, in present-day dollars. Note that this is a pack-level cost (as opposed to cell-level), so includes the cost of the battery management system, cooling system, fire-suppressing foam, etc. Should include the labor cost to replace the battery pack as well.

  • battery_cycle_life (float) – The number of charge/discharge cycles that the battery is expected to last before full replacement is required.

  • real_interest_rate (float) – The real interest rate per year. This is the interest rate minus the inflation rate. This is used to calculate the present-day value of future costs (e.g., airframe financing).

  • electricity_cost_per_kWh (float) – The cost of electricity, per kWh, in present-day dollars.

  • annual_expenses_per_crew (float) – The annual expenses per crew member, in present-day dollars. Should include the total burdened cost of the crew member, including salary, benefits, and other expenses.

  • ascent_time (float) – The time required to ascend to cruise altitude, in seconds.

  • descent_time (float) – The time required to descend from cruise altitude, in seconds.

Returns:

  • “airframe_depreciation”

    • ”airframe_financing”

    • ”insurance”

    • ”airframe_maintenance”

    • ”propulsion_maintenance”

    • ”battery_replacement”

    • ”energy”

    • ”crew”

    • ”airport_landing_fees”

    • ”airport_terminal_fees”

    • ”airport_parking_fees”

    • ”airport_passenger_facility_charge”

    • ”indirect”

One key, “total”, is also included, which is the sum of all of the above costs. Once again, this is

expressed in units of present-day dollars per passenger-mile.

Return type:

A dictionary of operating costs per passenger-mile, in present-day dollars, with the following keys

aerosandbox.library.costs.res[source]#