Aerodynamic Study of Trapezoidal and Rectangular Fins Using Semi Empirical and Numerical Methods

Lift and drag are two major aerodynamic forces that are important to consider in designing a rocket. A valid calculation of these forces is needed to predict the desired performance. This paper aims to investigate the aerodynamic forces acting on trapezoidal and rectangular fins. Semi-empirical methods using Datcom and numerical analysis using CFD software are conducted to calculate the aerodynamic forces. The calculation is done at Mach numbers 1.25, 1.5, 2.0, 2.5, and 3.0 and at angles of attack 0, 3, 6, 9, 12, and 15 degrees. The study shows that the aerodynamic forces calculated using Datcom method are in good accordance with CFD results, especially at a small angle of attack. The result also indicates that the trapezoidal fin has a greater lift-to-drag ratio compared to the rectangular fin.