RCAIDE.Library.Methods.Mass_Properties.Weight_Buildups.Conventional.Transport.FLOPS.compute_operating_items_weight

compute_operating_items_weight#

compute_operating_items_weight(vehicle)[source]#

Computes the weight of operating items using NASA FLOPS weight estimation method. Includes crew, baggage, unusable fuel, engine oil, passenger service items, weapons, and cargo containers.

Parameters:

vehicle (Vehicle) –

The vehicle instance containing:
  • networkslist
    Propulsion systems with:
    • propulsorslist

      Engine data for thrust and count

    • fuel_lineslist

      Fuel tank data

  • reference_areafloat

    Wing reference area [m²]

  • mass_properties.max_zero_fuelfloat

    Maximum zero fuel weight [kg]

  • flight_envelope.design_rangefloat

    Design range [nmi]

  • flight_envelope.design_mach_numberfloat

    Design cruise Mach number

  • mass_properties.cargofloat

    Cargo weight [kg]

  • passengersint

    Total passenger count

  • fuselageslist
    Fuselage data with optional:
    • number_coach_seatsint

      Number of economy seats

Returns:

output –

Container with weight breakdown:
  • miscfloat

    Weight of unusable fuel, engine oil, passenger service, cargo containers [kg]

  • flight_crewfloat

    Flight crew and baggage weight [kg]

  • flight_attendantsfloat

    Flight attendant and galley crew weight [kg]

  • totalfloat

    Total operating items weight [kg]

Return type:

Data

Notes

Uses FLOPS correlations developed from commercial transport aircraft data. For more details, please refer to the FLOPS documentation: https://ntrs.nasa.gov/citations/20170005851

Major Assumptions

  • If no tanks specified, assumes 5 fuel tanks

  • Default seat class distribution if not specified:

    • 5% first class

    • 10% business class

    • 85% economy class

  • If coach seats specified:

    • Remaining seats split 1/4 first class, 3/4 business

  • Crew requirements based on passenger count:

    • 2-3 flight crew (>150 pax = 3)

    • 1 attendant per 40 pax (min 1)

    • Additional galley crew for >250 pax

Theory Component weights computed using empirical correlations:

Unusable fuel weight: .. math:

W_{UF} = 11.5N_{eng}T_{SLS}^{0.2} + 0.07S_{ref} + 1.6N_{tank}W_{ZF}^{0.28}

Engine oil weight: .. math:

W_{oil} = 0.082N_{eng}T_{SLS}^{0.65}

Passenger service weight: .. math:

W_{srv} = (5.164N_{1st} + 3.846N_{bus} + 2.529N_{eco})(R/M)^{0.255}

Cargo container weight: .. math:

W_{con} = 175 \lceil \frac{W_{cargo}}{950} \rceil
where:

  • N_eng = number of engines

  • T_SLS = sea level static thrust

  • S_ref = wing reference area

  • N_tank = number of fuel tanks

  • W_ZF = zero fuel weight

  • N_1st/bus/eco = number of seats by class

  • R = design range

  • M = design Mach number

  • W_{cargo} = cargo weight

References

[1] NASA Flight Optimization System (FLOPS)