Computational fluid dynamics based winglet design and analysis of GL-1 glider

Winglet is one of the effective devices that installed in wing tip to reduce induced drag which is the second largest contribution of drag especially in low-speed aircraft. The largest contribution of induced drag is from wingtip vortices. On previous study, GL-1 was not employing by winglet and the aerodynamic efficiency LD was 27 or corresponding to 11.7 km maximum range. However, that value was below from conceptual design result which is 30 or equal to 13.7 km maximum range. The objective is to improve aerodynamic efficiency LD of GL-1 glider 30 by introducing the winglet. The problem is determining winglet geometry that could reach design target. So, study of parametric method is conducted including winglet height study, sweep angle study, and taper ratio study. To produce desired aerodynamic characteristic from winglet, computational fluid dynamics method with solving Reynold Averaged Shear Stress coupled with Shear Stress Transport and Gamma-Theta transition model is used. After utilizing winglet to GL-1, CL increased by 3.4106 percent, CD reduced by 3.2068 percent, and aerodynamic efficiency LD. increased by 6.8366 percent the maximum range has increased from 11.7 to 12.5 km.