Design of rotation inducing rocket fins and their analysis for aerodynamic stability

Abstract

The stability of a rocket during flight is the one of the most crucial factors from the perspective of a design engineer. Without stability, a rocket is equivalent to an uncontrolled and unpredictable, high-speed projectile. Passive control can stabilize flight in one of two ways: by shifting the center of pressure (CP) behind the center of gravity (CG); or by producing a spin along the axis of flight. This study aims to induce this spin or rotation through the design of fins. This study is a synergistic application of few of the many engineering practices and processes. It has generated airfoil profiles for rotation inducing fins using NACA database; developed a software model using SolidWorks to run analysis using commercial FEA, CFD and stability analysis software; and additively manufactured a prototype model for experimental testing in a subsonic wind tunnel. Pressure, which is responsible for spin, was measured experimentally at different locations across the length of the model and was found to have comparable values as those obtained for CFD study. The experiment also displayed a longitudinally stable spin of the model.