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Keywords

Roll stability, Aerodynamic dihedral, Lateral stability analysis, Vortex lattice method

Document Type

Article

Abstract

This study investigates the lateral stability of a fixed-wing aircraft through the roll-moment stability derivative (C_lβ ), treated as the primary indicator of dihedral effect and overall roll stability. A coupled DATCOM-based analytical formulation and lifting-line/VLM modeling framework has been used to quantify the influence of the key geometric and aerodynamic parameters on the roll-stability derivative. Specifically, the influences of dihedral angle, angle of attack, and sideslip have been explored separately, followed by geometric factors such as aspect ratio, taper ratio, and sweep angle in a systematic way. It is observed that there is an increase in the dihedral angle from 5° to 15°; hence, there is an improvement of about 230–260% in (C_lβ ), which underlines the great stabilization role of dihedral geometry. Variations in the angle of attack from 0° to 15° produce a 150–190% change in the same derivative, demonstrating significant nonlinear sensitivity under increased aerodynamic loading. Three-dimensional stability maps further confirm that (C_lβ ) increases monotonically with both dihedral angle ($\Gamma $) and angle of attack (α ), while sideslip angle (β ) primarily scales its magnitude principally without changing its trend. Focusing on (C_lβ ), as the primary stability determinant, provides a clear physical interpretation of lateral-stability trends and strengthens the link between wing geometry and roll-stability performance across the operating envelope.

DOI

10.65645/3105-9104.1032

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