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

compute_propulsion_system_weight

compute_propulsion_system_weight(vehicle, network)

Calculate the weight of the complete propulsion system using FLOPS methodology.

Parameters:

• vehicle (RCAIDE.Vehicle()) –

  Vehicle data structure containing:

  • networkslist

    List of all propulsion networks

  • design_mach_numberfloat

    Design cruise Mach number

  • mass_properties.max_zero_fuelfloat

    Maximum zero fuel weight [kg]

• network (RCAIDE.Network()) – Network data structure

Returns:

output –

Data structure containing:

• W_propfloat

  Total propulsion system weight [kg]

• W_thrust_reverserfloat

  Thrust reverser weight [kg]

• W_starterfloat

  Starter engine weight [kg]

• W_engine_controlsfloat

  Engine controls weight [kg]

• W_fuel_systemfloat

  Fuel system weight [kg]

• W_nacellefloat

  Nacelle weight [kg]

• W_enginefloat

  Dry engine weight [kg]

• number_of_enginesint

  Total number of engines

• number_of_fuel_tanksint

  Total number of fuel tanks

Return type:

Data()

Notes

Calculates weights for all propulsion system components based on engine type and configuration.

Major Assumptions

• No mixed propulsion (either all piston or all turbine)

• Piston engines have no thrust reversers, engine controls, or starters

• All engines of same type are identical

• All nacelles are identical

compute_piston_engine_weight(ref_propulsor)

Calculate the dry engine weight for piston engines based on power.

Parameters:

ref_propulsor (RCAIDE.Component()) –

Propulsor data structure containing:

• engine.sea_level_powerfloat

  Sea level power of engine [kW]

Returns:

WENG – Dry engine weight [kg]

Return type:

float

Notes

Uses linear regression based on real engine data.

Major Assumptions

• Linear relationship between engine weight and power

• Valid for engines between 48 and 313 kW (64 to 420 hp)

Theory

\[W_{eng} = 0.8953 * P_{SL} + 19.121\]

Where:

• W_{eng} is engine weight [kg]

• P_{SL} is sea level power [kW]

References

[1] Based on 26 GA aircraft engines from Rotax, Lycoming, and Continental

compute_turbine_engine_weight(vehicle, ref_propulsor)

Calculate the dry engine weight for turbine engines using FLOPS methodology.

Parameters:

• vehicle (RCAIDE.Vehicle()) – Vehicle data structure

• ref_propulsor (RCAIDE.Component()) –

  Propulsor data structure containing:

  • sealevel_static_thrustfloat

    Sea level static thrust [N]

Returns:

WENG – Dry engine weight [kg]

Return type:

float

Notes

Uses FLOPS weight estimation method for turbine engines.

Major Assumptions

• Engine weight scaling parameter is 1.15

• Engine inlet weight scaling exponent is 1

• Baseline inlet and nozzle weights are 0 lbs

Theory

\[W_{eng} = \frac{T_{SLS}}{5.5} * (\frac{T}{T_{SLS}})^{1.15}\]

Where:

• W_{eng} is engine weight [lb]

• T_{SLS} is sea level static thrust [lb]

• T is rated thrust [lb]

compute_nacelle_weight(ref_propulsor, ref_nacelle, NENG)

Calculate the nacelle weight using FLOPS methodology.

Parameters:

• ref_propulsor (RCAIDE.Component()) –

  Propulsor data structure containing:

  • sealevel_static_thrustfloat

    Sea level static thrust [N]

• ref_nacelle (RCAIDE.Component()) –

  Nacelle data structure containing:

  • diameterfloat

    Nacelle diameter [m]

  • lengthfloat

    Nacelle length [m]

• NENG (int) – Number of engines

Returns:

WNAC – Nacelle weight [kg]

Return type:

float

Notes

Uses FLOPS weight estimation method for engine nacelles.

Major Assumptions

• All nacelles are identical

• Number of nacelles equals number of engines

Theory

\[W_{nac} = 0.25 * N * D * L * T^{0.36}\]

Where:

• W_{nac} is nacelle weight [lb]

• N is number of nacelles

• D is nacelle diameter [ft]

• L is nacelle length [ft]

• T is sea level static thrust [lb]

compute_thrust_reverser_weight(ref_propulsor, NENG)

Calculate the thrust reverser weight using FLOPS methodology.

Parameters:

• ref_propulsor (RCAIDE.Component()) –

  Propulsor data structure containing:

  • sealevel_static_thrustfloat

    Sea level static thrust [N]

• NENG (int) – Number of engines

Returns:

WTHR – Thrust reverser weight [kg]

Return type:

float

Notes

Uses FLOPS weight estimation method for thrust reversers.

Theory

\[W_{tr} = 0.034 * T * N\]

Where:

• W_{tr} is thrust reverser weight [lb]

• T is sea level static thrust [lb]

• N is number of engines

compute_misc_propulsion_system_weight(vehicle, ref_propulsor, ref_nacelle, NENG)

Calculate miscellaneous propulsion system weights using FLOPS methodology.

Parameters:

• vehicle (RCAIDE.Vehicle()) –

  Vehicle data structure containing:

  • design_mach_numberfloat

    Design cruise Mach number

• ref_propulsor (RCAIDE.Component()) –

  Propulsor data structure containing:

  • sealevel_static_thrustfloat

    Sea level static thrust [N]

• ref_nacelle (RCAIDE.Component()) –

  Nacelle data structure containing:

  • diameterfloat

    Nacelle diameter [m]

• NENG (int) – Number of engines

Returns:

• WEC (float) – Engine control system weight [kg]

• WSTART (float) – Starter engine weight [kg]

Notes

Calculates electrical control system and starter engine weights.

Theory

Engine controls: .. math:

W_{ec} = 0.26 * N * T^{0.5}

Starter: .. math:

W_{st} = 11.0 * N * M^{0.32} * D^{1.6}

Where:

• W_{ec} is engine controls weight [lb]

• W_{st} is starter weight [lb]

• N is number of engines

• T is sea level static thrust [lb]

• M is design Mach number

• D is nacelle diameter [ft]

compute_fuel_system_weight(vehicle, NENG)

Calculate the weight of the general aviation aircraft fuel system using FLOPS methodology.

Parameters:

• vehicle (RCAIDE.Vehicle()) –

  Vehicle data structure containing:

  • mass_properties.max_fuelfloat

    Maximum fuel capacity [kg]

• NENG (int) – Number of engines

Returns:

fuel_system_weight – Weight of the complete fuel system [kg]

Return type:

float

Notes

The function implements the FLOPS weight estimation method for aircraft fuel systems. The calculation accounts for total fuel capacity and number of engines.

Major Assumptions

• Conventional fuel tank and distribution system

• System includes tanks, plumbing, pumps, and associated hardware

• Weight scales with total fuel capacity and number of engines

Theory

The FLOPS fuel system weight estimation follows:

\[W_{fs} = 1.07 * W_{f}^{0.58} * N_{eng}^{0.43}\]

Where:

• W_{fs} is fuel system weight [lb]

• W_{f} is maximum fuel weight [lb]

• N_{eng} is number of engines

References

[1] NASA. (1979). The Flight Optimization System Weights Estimation Method.

NASA Technical Report.