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

compute_propulsion_system_weight#

compute_propulsion_system_weight(vehicle, ref_propulsor)[source]#

Computes the complete propulsion system weight using NASA FLOPS weight estimation method. Includes engines, nacelles, thrust reversers, and associated systems.

Parameters:
  • vehicle (Vehicle) –

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

        Engine data

      • fuel_lineslist

        Fuel system data with fuel tanks

    • design_mach_numberfloat

      Design cruise Mach number

    • mass_properties.max_zero_fuelfloat

      Maximum zero fuel weight [kg]

    • systems.accessoriesstr

      Aircraft type (‘short-range’, ‘commuter’, ‘medium-range’, ‘long-range’, ‘sst’, ‘cargo’)

  • ref_propulsor (Propulsor) –

    Reference engine containing:
    • sealevel_static_thrustfloat

      Sea level static thrust [N]

    • nacelleNacelle
      Nacelle geometry with:
      • diameterfloat

        Maximum diameter [m]

      • lengthfloat

        Total length [m]

Returns:

output

Container with propulsion weight breakdown:
  • W_propfloat

    Total propulsion system weight [kg]

  • W_enginefloat

    Dry engine weight [kg]

  • W_thrust_reverserfloat

    Thrust reverser weight [kg]

  • W_starterfloat

    Starter system weight [kg]

  • W_engine_controlsfloat

    Engine controls weight [kg]

  • W_fuel_systemfloat

    Fuel system weight [kg]

  • W_nacellefloat

    Nacelle weight [kg]

  • number_of_enginesint

    Total engine count

  • number_of_fuel_tanksint

    Total fuel tank count

Return type:

Data

Notes

Uses FLOPS correlations developed from transport aircraft database.

Major Assumptions
  • Engines have a thrust to weight ratio of 5.5

  • All nacelles are identical

  • Number of nacelles equals number of engines

  • Number of thrust reversers equals the number of engines unless there is an odd number of engines in which case it is N - 1

Theory Engine weight is computed using: .. math:

W_{eng} = THRUST/5.5

Nacelle weight is computed using: .. math:

W_{nac} = 0.25N_{nac}D_{nac}L_{nac}T^{0.36}

Thrust reverser weight is computed using: .. math:

W_{rev} = 0.034T N_{nac}
where:
  • W_base = baseline engine weight

  • T = sea level static thrust

  • N_nac = number of nacelles

  • D_nac = nacelle diameter

  • L_nac = nacelle length

References

[1] NASA Flight Optimization System (FLOPS)

compute_nacelle_weight(ref_propulsor, ref_nacelle, NENG)[source]#

Calculates the nacelle weight based on the FLOPS method

Assumptions:
  1. All nacelles are identical

  2. The number of nacelles is the same as the number of engines

Source:

The Flight Optimization System Weight Estimation Method

Inputs:
ref_propulsor - data dictionary for the specific network that is being estimated [dimensionless]

-.number_of_engines: number of engines -.engine_lenght: total length of engine [m] -.sealevel_static_thrust: sealevel static thrust of engine [N]

nacelle.

-.diameter: diameter of nacelle [m]

WENG - dry engine weight [kg]

Outputs:

WNAC: nacelle weight [kg]

Properties Used:

N/A

compute_thrust_reverser_weight(ref_propulsor, NENG)[source]#

Calculates the weight of the thrust reversers of the aircraft

Assumptions:

Source:

The Flight Optimization System Weight Estimation Method

Inputs:
ref_propulsor - data dictionary for the specific network that is being estimated [dimensionless]

-.number_of_engines: number of engines -.sealevel_static_thrust: sealevel static thrust of engine [N]

Outputs:

WTHR: Thrust reversers weight [kg]

Properties Used:

N/A

compute_misc_propulsion_system_weight(vehicle, ref_propulsor, ref_nacelle, NENG)[source]#

Calculates the miscellaneous engine weight based on the FLOPS method, electrical control system weight and starter engine weight

Assumptions:
  1. All nacelles are identical

  2. The number of nacelles is the same as the number of engines

Source:

The Flight Optimization System Weight Estimation Method

Inputs:
vehicle - data dictionary with vehicle properties [dimensionless]

-.design_mach_number: design mach number

ref_propulsor - data dictionary for the specific network that is being estimated [dimensionless]

-.number_of_engines: number of engines -.sealevel_static_thrust: sealevel static thrust of engine [N]

nacelle

-.diameter: diameter of nacelle [m]

Outputs:

WEC: electrical engine control system weight [kg] WSTART: starter engine weight [kg]

Properties Used:

N/A

compute_fuel_system_weight(vehicle, NENG)[source]#

Calculates the weight of the fuel system based on the FLOPS method Assumptions:

Source:

The Flight Optimization System Weight Estimation Method

Inputs:
vehicle - data dictionary with vehicle properties [dimensionless]

-.design_mach_number: design mach number - [kg]

Outputs:

WFSYS: Fuel system weight [kg]

Properties Used:

N/A

compute_engine_weight(vehicle, ref_propulsor)[source]#

Calculates the dry engine weight based on the FLOPS method Assumptions:

Rated thrust per scaled engine and rated thurst for baseline are the same Engine weight scaling parameter is 1.15 Enginge inlet weight scaling exponent is 1 Baseline inlet weight is 0 lbs as in example files FLOPS Baseline nozzle weight is 0 lbs as in example files FLOPS

Source:

The Flight Optimization System Weight Estimation Method

Inputs:
vehicle - data dictionary with vehicle properties [dimensionless]
-.systems.accessories: type of aircraft (short-range, commuter

medium-range, long-range, sst, cargo)

ref_propulsor - data dictionary for the specific network that is being estimated [dimensionless]

-.sealevel_static_thrust: sealevel static thrust of engine [N]

Outputs:

WENG: dry engine weight [kg]

Properties Used:

N/A