RCAIDE.Library.Methods.Stability.Vortex_Lattice_Method.compute_neutral_point

compute_neutral_point#

compute_neutral_point(stability, vehicle)[source]#

Computes the neutral point of an aircraft using Vortex Lattice Method optimization.

Parameters:

stability (RCAIDE.Framework.Analyses.Stability) –

Stability analysis object containing:
  • vehicleRCAIDE.Library.Components.Vehicle

    Vehicle object with geometry and mass properties

  • settingsRCAIDE.Framework.Analyses.Stability.Settings

    Stability analysis settings

  • trainingData

    Training data for analysis - angle_of_attack : numpy.ndarray

    Array of angle of attack values [radians]

    • Machnumpy.ndarray

      Array of Mach numbers [unitless]

Returns:

The neutral point is stored in vehicle.neutral_point

Return type:

None

Notes

This function computes the neutral point of an aircraft by finding the center of gravity location where the pitching moment coefficient derivative with respect to angle of attack is zero. It uses an optimization approach with the Vortex Lattice Method to evaluate aerodynamic characteristics. It specifically uses the Scipy SLSQP solver.

Major Assumptions

  • Linear aerodynamics within the analysis range

  • Control surfaces are removed for clean configuration analysis

  • Vortex Lattice Method accurately represents the aerodynamics

  • Small angle approximations apply

Theory

The neutral point is defined as the center of gravity location where: \(\frac{\partial C_M}{\partial \alpha} = 0\)

Definitions

‘Neutral Point’

Center of gravity location where the aircraft has neutral static stability (i.e. Cm_alpha = 0).

neutral_point_objective(cg_location, conditions, settings, clean_wing_vehicle_np, Mach, AoA)[source]#

Objective function for neutral point optimization.

Parameters:

  • cg_location (list) – Center of gravity location [m]

  • conditions (RCAIDE.Framework.Mission.Common.Results) – Flight conditions for VLM analysis

  • settings (RCAIDE.Framework.Analyses.Stability.Settings) – Stability analysis settings

  • clean_wing_vehicle_np (RCAIDE.Library.Components.Vehicle) – Clean wing vehicle configuration (no control surfaces)

  • Mach (numpy.ndarray) – Array of Mach numbers [unitless]

  • AoA (numpy.ndarray) – Array of angle of attack values [radians]

Returns:

Absolute value of pitching moment coefficient derivative with respect to angle of attack

Return type:

float

Notes

This function serves as the objective function for the neutral point optimization. It updates the vehicle center of gravity, runs VLM analysis, and computes the pitching moment coefficient derivative to minimize.

Major Assumptions

  • VLM analysis is valid for the given conditions

  • Pitching moment coefficient varies linearly with angle of attack

  • Clean wing configuration represents the neutral point condition